Description:
This invention relates to a pin-setting device for resetting fallen pins on a playing surface, and more particularly to a device for setting pins used in a bowling game known as "five pins."
In five pin bowling, the pins are arranged in V formation with a central or head pin being nearest the bowler. Originally the pins were reset by hand either by placing each pin individually on the playing surface at one of five pin locations or by pulling strings which raise the pins up and then lower then back into the desired positions. In recent years however, automatic devices have become available for resetting the pins.
It is desirable that an automatic pin-setting device should be relatively inexpensive to install, be simple and reliable and require a minimum of maintenance. The device should preferably be light for moving it into position over a bowling surface and simple to inspect for proper operation.
There are three main types of pin-setting devices available. The first type has an elevator which moves along an upright track for elevating pins from behind the playing surface onto a belt which runs longitudinally forwards to transport the pins through a series of gates and chutes. The gates selectively deliver the pins into chutes which guide the pins into a setting mechanism. The device relies on the pins to trip switches for controlling the gates and includes complex machinery for driving moving parts. This type of device is relatively complex, expensive, heavy and difficult to maintain.
A second type of pin-setting device which is presently available uses a vertical elevator for moving the pins up to a horizontal transporter which moves the pins into a storage area. When there are five pins in the storage area a relay is tripped which ejects the pins forwardly into downwardly extending tracks, each track receiving one pin. The pins are stored in these tracks and then allowed to fall as required into a setting mechanism. There is a tendency for pins to become jammed in the tracks and also because of the height of the vertical transporter there is noticeable damage to the pins as they fall off the elevator and impact with other pins at the bottom of the elevator.
In both of the types described thus far, the setting mechanism which sets the pins on the playing surface or deck is also used for lifting the pins during a clearing sequence. Upright pins are first lifted so that fallen pins can be swept off the playing surface before placing the upright pins back on the playing surface. The mechanism associated with this sequence is relatively complex and expensive to manufacture.
A third type of pin-setting device includes cords attached to the pins for resetting the pins. After a pin has been knocked over the cords are pulled tightly to raise the pins upwardly into a recess for locating the pins and then the pins are allowed to air slowing downwardly into position on the playing surface. Some difficulty has been encountered with this type of machine due to cords attached to the pins. Players have agreed to play the game according to the machine rather than to the actual score. For instance, it is possible that one of the pins is left standing and yet the machine resets all of the pins indicating that all of the pins were knocked down. The players agree to score as if all of the pins had been knocked down. Although this machine has many advantages in that it is relatively light and inexpensive, there is nevertheless a player resistance to this type of machine because of the cords.
In general it is one of the objects of the present invention to provide a pin-setting device which is relatively light, comparatively inexpensive and which exerts a more positive control over the movement of the pins between the fallen position and a reset upright position on the playing surface.
Accordingly, in one of its aspects the present invention provides a pin-setting device having a distributor for receiving pins from a distributor feeding system and locating the pins in the desired V-arrangement used in five pin bowling, the pins being held in a positive upright position during distribution, and a setting mechanism which strips pins off the distributor and lowers them onto the playing surface.
In another of its aspects, the present invention provides a pin-setting device having a setting mechanism for placing the pins on the playing surface and a separate clearing mechanism for lifting pins off the playing surface while fallen pins are swept off the playing surface.
In another of its aspects, the present invention provides a setting mechanism for stripping pins off a distributor and placing the pins on the playing surface, the setting mechanism supporting the pins in V-arrangement.
In yet another of its aspects, the present invention provides a clearing mechanism for lifting up upright pins from the playing surface, including pins which have been displaced from their original position and then placing the pins back on the playing surface in the displaced position.
These and other aspects of the invention will be better understood with reference to the drawings wherein:
FIG. 1 is a perspective view, partly broken away to show the construction of a pin-setting device according to the invention;
FIG. 2 is a sectional side view of a system for feeding pins to an elevator;
FIG. 3 is a perspective view of the elevator feeding system and the elevator;
FIG. 4 is an exploded perspective view of a portion of the elevator;
FIG. 5 is a perspective view of a lower part of the elevator;
FIG. 6 is a sectional side view of an upper part of the elevator showing the transfer of pins from the elevator to a distributor feeding system;
FIGS. 7 and 8 are sectional side views of the distributor feeding system showing the operation of the system for transporting a pin to a distributor;
FIGS. 9 and 10 are perspective views of parts of the distributor to illustrate the distributor picking up a pin from the distributor feeding system;
FIGS. 11 and 12 also illustrate parts of the distributor shown in FIGS. 9 and 10;
FIG. 13 is a diagram showing the geometrical relationships between the positions of the pins when set on the playing surface;
FIG. 14 is a plan view, partly in section showing the distributor and an associated indexing mechanism;
FIG. 15 is a view similar to FIG. 14 showing the operation of the distributor;
FIG. 16 is a perspective view of a pin carrier forming part of a setting mechanism for stripping pins from the distributor and placing the pins on the playing surface;
FIGS. 17 and 18 are sectional side views of the pin-setting device illustrating the operation of the setting mechanism;
FIGS. 19 and 20 illustrate movements of a gate forming part of the setting mechanism;
FIG. 21 is a sectional side view of the pin-setting device illustrating a clearing mechanism for lifting upright pins while fallen pins are swept off the playing surface;
FIG. 22 is a top view, partly broken away, of part of the clearing mechanism for gripping the pins;
FIG. 23 is a sectional side view of a part of the device showing a sweeping mechanism for removing pins from the playing surface;
FIGS. 24 to 28 show the arrangements of some of the sensing devices used in controlling the sequential movements of the pin-setting device;
FIG. 29 is a perspective diagrammatic view of a drive system for use in driving the rotating moving parts of the pin setting device; and
FIGS. 30 (Part I) and 30 (Part II), taken together, constitue a diagrammatic illustration of a pneumatic circuit for controlling the device automatically and for responding to signals from a player.
In five pin bowling, each bowler is allowed three balls with which he can attempt to knock down the five pins set up by a pin-setting device. If he knocks down some of the pins with either of his first two balls there is a likelihood that these pins will remain on the playing surface between upright pins. The bowler then presses a button to clear the playing surface and the pin-setting device responds by lifting up the pins which are standing and sweeping the fallen pins rearwardly off the playing surface. The upright pins are then lowered onto the playing surface ready for the bowler to attempt to knock them down. Once the bowler has either knocked down all of the pins or used the three balls allowed he then presses a further button to set a further five pins and the device responds by sweeping thee playing surface to remove any pins which remain on the surface and then placing five new pins on the playing surface.
The essential mechanisms and systems of the pin-setting device will now be described with reference to FIG. 1, in which a pin setting device 50 is mounted over an end portion 52 of a playing surface and includes an elevator feeding system 54 for receiving pins from a rear end 56 of the playing surface and transporting the pins and balls to an elevator 58. The pins and balls are lifted by the elevator onto a distributor feeding system 60 which transports the pins forwardly and permits the balls to roll rearwardly and transversely down a track 62 and onto a ramp 64 which guides them forwardly to the bowler. Distributor feeding system 60 receives orientated pins from the elevator and carries the pins forwardly into an upright position before the pins are picked up by a distributor 66 which is indexed by a mechanism (not shown in this view) for arranging the pins in the desired V configuration. A setting mechanism 68 is adapted to strip pins off the distributor 66 and lower the pins in V configuration onto the playing surface 52. The device 50 also includes a clearing mechanism 70 which operates separately and distinctly from setting mecahnism 68 to lift up standing pins so that fallen pins can be removed rearwardly by a sweeping mechanism 72.
As each pin is transported from behind the playing surface and back on to the playing surface, a series of pneumatic sensing devices are opened and closed to ensure the proper logical sequence of events. These sensing devices also control parts of a drive system 74 for moving rotating parts of the pin-setting device 50 and are part of a logic circuit for ensuring proper operation of the device.
The device 50 will be described firstly with reference to the mechanisms and systems in the order in which they were introduced with reference to FIG. 1. After describing these various mechanisms and systems, the pneumatic sensing devices, drive system and logic circuit will then be described. For ready reference, a series of headings will be used according to the terminology already developed in describing FIG. 1.
A. elevator Feeding System, 54
As seen in FIG. 1, the elevator feeding system 54 transports pins from the rear end 56 of the playing surface 52 rearwardly to the elevator 58.
Reference is made to FIGS. 2 and 3 in which the feed system 54 includes a vibrator 76 mounted on a base frame 78 and including an inclined board 80. Pins falling off playing surface 52 onto the board 80 are made to move down the board by an eccentric drive 82 which is coupled by a tie rod 84 to a board support 86 attached to board 80. The board 80 moves longitudinally along a path controlled by respective long and short links 88, 90 pivotally coupled to the frame 78 and support 86. As a result the pins tend to move downwardly and rearwardly along the board 80 ending either on a transversely moving conveyor 92 or a relatively short longitudinally moving conveyor 94 (FIG. 3). Longitudinally extending guides 95 on the vibrator board 80 and stationary boards 96 ensure that pins do not fall off the vibrator board 80 and conveyors 92, 94, and a transversely extending board 98 guides the pins on the conveyor 92. The vibrator 76 is driven continuously whereas the conveyors 92, 94 are stopped when no further pins are required at the distributor.
B. elevator, 58
As seen in FIG. 1, the elevator 58 is positioned at the rear of the pin-setting device 50 and operated to pick up pins from the feeding system 54 and lift the pins onto the distributor feeding system 60. The elevator is driven intermittently and stopped only when there are sufficient pins to fill the distributor as will be described.
Reference is made to FIGS. 3 and 4 in which the elevator 58 includes an upright oval track 100 defined by rails 102, 104 for guiding carriages 106 on which respective trays 108 are mounted. Each carriage 106 and tray is adapted to elevate one pin at a time from the feeding mechanism 54 to the distributor feeding system 60. Each of the carriages 106 has wheels 110 adapted to roll relatively freely in respective channels 112, 114 formed in the rails 102, 104. Each tray 108 has a raised U-shaped rib 116 which combines with a back flange 118 to locate the pin as will be described. Carriages 106 are attached to a continuous flat belt 120 and a pulley belt 122 is engaged against the flat belt 120 for driving the carriages in the rails 102, 104. The arrangement of the pulley belt 122 will be described under the heading `Drive System` with reference to FIG. 29.
As seen in FIG. 5, the pins used in five pin bowling have a bulbous lower end, a neck and an enlarged head. A band of rubber or other resilient material is positioned about the bulbous portion to cushion the impact when a ball strikes the pin. The band makes movement of the pins relatively difficult because it tends to catch on parts of the device and trap the pin. Consequently the device must be designed so that there is little likelihood that the band could interfere with proper movement of the pins. For instance, the trays 108 are spaced apart and shaped so that a pin which attempts to find its way head first onto a tray engages against a back stop 124 and the distance from the top of the pin to the band is such that should the head of the pin be adjacent the underside of a preceding tray, the band cannot engage the rib 116 on the succeeding tray. This prevents a pin being picked up by a tray and remaining on the tray with the head of the pin towards the back of the tray. Normally if a pin engages a tray head first, the weight of the bulbous portion of the pin will be sufficient to cause the pin to fall off the tray once the tray starts to move upwardly. The pin then falls onto a curved surface 126 and back onto the conveyor 94.
A further possibility is that two pins engage on the same tray as shown in FIG. 5. In this event the upper of the pins is in the right position but the second pin is in the tray head first. The curved surface 126 provides some support for the pins initially. However, when the pins reach the upper extremity of the surface 126 pins then fall off the tray and back onto the transverse conveyor 92 where they are less likely to collide with other pins because the pins tend to accumulate on the longitudinal conveyor 94. The pins are then transported by the conveyors 92, 94 back into position for engagement with the trays 108.
Because of the shape of the bowling pins, each pin can be supported on trays 108 with its axis misaligned with respect to the longitudinal axis of the playing surface and of the device 50. (FIG. 1). As seen in FIG. 6 rails 128, 130 are provided to align the pins as the pins move vertically towards the distributor feeding system. The rails contact the neck of the pin to bring the axis of the pin generally into alignment with the axis of the device so that the pin is then ready for transfer to the distributor feeding system. The pins then roll off the trays 108 onto a relatively narrow conveyor 132 for moving the pins towards distributor 66 (FIG. 1).
As the pin passes between rails 128, 130 it strikes a pneumatic sensing device 134 and then as it is transported along conveyor 132 it strikes a second sensing device. The function of these sensing devices will be described under the heading "logic circuit."
The trays 108 are also shaped for receiving balls which are elevated onto the conveyor 132 in a similar fashion to the pins. However, the balls do not contact the sensing device 134 or the sensing device 136 and because the conveyor 132 is inclined downwardly and rearwardly, the balls roll onto the track 62 and then down the ramp 64 to the bowler.
C. distributor Feeding System, 60
As seen in FIG. 1, the distributor feeding system 60 receives pins from the elevator 58 and transports them forwardly for pick up by the distributor 66.
Reference is now made to FIGS. 6, 7 and 8. As seen in FIG. 6, the pin is guided by side walls 137, as it is transported forwardly by the conveyor 132. Conveyor 132 is driven continuously independently of the elevator whether or not the distributor requires more pins. The drive to elevator feeding system, elevator and distributor feeding system will be described in more detail with reference to the drive system.
As seen in FIG. 7, the pin is transported forwardly head first on the conveyor 132 until the head of the pin engages a curved plate 138 which guides the head of the pin upwardly as the conveyor 132 continues to transport the bottom of the pin forwardly. This pin movement continues until the pin falls into a U-shaped cup 140. The ring around the pin engages in the cup and the bottom of the pin opens a sensing device 142 which is also part of the logic circuit. Cup 140 is pivotally attached to respective first ends of a pair of links 144 and to a further link 146. The other ends of links 144 are attached to a common shaft 148 and a crank 150 is also attached to this shaft. The distal end of the crank 150 is pivotally coupled to a pneumatic actuator 152 for rotating the crank 150 and shaft 148 to elevate the cup 140 into the position shown in FIG. 8. The length of the links 144, 146 are chosen so that in the position shown in FIG. 7 the pin is inclined forwardly and in the position shown in FIG. 8 the pin is generally vertical. Once the pin is in the position shown in FIG. 8 it is ready to be received by the distributor 66 in the manner shown in chain-dotted outline in FIG. 8. The actuator then moves the cup 140 downwardly into the position shown in FIG. 7 for receiving a further pin.
D. distributor, 66
As seen in FIG. 1, the distributor 66 receives pins from the distributor feeding system 60 and arranges them in a V formation so that the setting mechanism 68 can strip the pins off the distributor 66 and place the pins on the playing surface 52. The distributor is driven by an indexing mechanism. However, for simplicity of description the distributor will be described first before describing the indexing mechanism.
Reference is made to FIGS. 9 and 10 which illustrate the operation of one of six pick-up mechanisms 154 adapted to receive pins from the distributor feeding system 60. Each of the mechanisms 154 includes a guide plate 156 to which is attached a pair of location pins 158, 159 guided in channels in the underside of a stationary distributor plate 160. The channels are not shown in these views and will be described in detail with reference to FIG. 14. A distributor rotor 162 has six arms 164 each of which is coupled to a respective one of six pick-up mechanisms 154 at its distal end.
Considering the mechanism 154 shown as typical of all six mechanisms, guide plate 156 is attached to a short axle 166 rotatably mounted in a boss 168 at the end of arm 164 and connected to a downwardly extending location element 170 so that the plate 156 and element 170 rotate with respect to the arm 164. The element 170 is curved downwardly and includes an upright portion 172 having a generally V-shaped cross-section for combining with a shoe 173 to grip a pin about the neck of the pin. The shoe is pivotally mounted on an extension 175 of element 170 and is spring-loaded and biased upwardly into the position shown in FIG. 9. The arms 164 are driven by the indexing mechanism towards a deflector 174 mounted on a bracket 176 on the plate 160 so that the shoe 173 meets an upwardly curved leading end 178 of the deflector 174 and is moved into the position shown in FIG. 10. At this point the rotor stops and the cup 140 is moved upwardly into the FIG. 8 position to push the head of the pin between the shoe 173 and upright portion 172 as seen in FIGS. 11 and 12. The deflector 174 is sufficiently resilient to permit the shoe 173 to rotate so that the head of the pin passes the shoe and then the deflector pushes the shoe back into the FIG. 10 position whereby the pin is locked in place supported by the pick-up mechanism 154. The weight of the pin is such that it retains the shoe 173 in the position shown in FIG. 10 so that the pin is effectively locked against downward movement and suspended from the mechanism 154. However, the pin is free to move upwardly and the shape of the shoe is such that upon moving the pin upwardly the shoe rotates back into the FIG. 9 position. The pin can then be withdrawn downwardly from the pick-up mechanism 154.
As the rotor continues to turn the distributor feeding system places another pin in position for engagement with the next mechanism 154 on the succeeding arm 164. As will be described, these movements continue until five pins are supported, one pin in each of five of the mechanisms 154.
Reference is next made to FIG. 13 which shows the geometrical relationships between thee positions of the pins when set for bowling. The pins are arranged in a standard V-formation with the arms of the V 60° apart and the mid-pin of each arm a distance of 18 inches from neighboring pins. As seen in FIG. 13, thee position of the pins are indicated as follows: head pin 180; middle pins 182 and 184; and end pins 186 and 188. The outer circle radius R2 is the path which a pin would follow from a position shown in FIG. 10 if it were free to move in a circle about the centre of the rotor 162 (FIG. 9) and the inner circle radius R1 is the path followed by the axis of boss 168 (FIG. 9) in completing one revolution about the axis of the rotor 162. The head pin 180 and end pins 186, 188 lie on the outer circle radius R2 on radial lines spaced 120° apart and the pins 182, 184 lie on the radial lines drawn to respective pins 188, 186 if these lines are projected past the centre of the circle. Radii R1 and R2 are related such that twice the difference between radii R1 and R2 is equal to the radial distance between pin position 184 and the circle radius R2.
If the radii are to satisfy this relationship, and the angle between the line joining pins 180 and 188 and the line between pins 180 and 186 is to be 60° with the distance between pins 180 and 182 equal to 18 inches, then the radius R2 is equal to 12√ 3 or 20.784 inches, the radius R1 equals 9√3 or 15.588 inches, and the pin positions 182, 184 are respectively 6√ 3 or 10.392 inches from the axis of the rotor. As a result the distance between the axis of boss 168 (on circle radius R1) and the pin 180 is 3√ 3 inches so that if mechanism 154 is rotated through 180 degrees while the arm 164 is rotating through 60°, the pin 180 moves from its position as drawn into position 182. This pin movement is controlled by the aforementioned channels in plate 160 (FIG. 9) as will be described.
Reference is now made to FIG. 14 in which pin positions are related by the numerals used for the pin positions of FIG. 13. In order to describe the movements of the distributor, first consider a bowling pin 190 which the distributor has just received from the distributor feeding system 60 (FIG. 1). The distributor moves clockwise as drawn and the location pins 158, 159 of the pick-up mechanism 154 are guided by the outer wall of a peripheral channel 192 formed in the underside of plate 160. As the rotor 162 rotates, the location pins 158, 159 move along a circular portion of the channel until leading location pin 158 meets a tangential portion 196 of the channel and follows this portion towards a radial slot 194. There is now a tendency for the guide plate 156 to rotate because pin 159 cannot follow pin 158 down the tangential portion 196. As the plate 156 rotates a leading end of the plate engages in radial slot 194 and a recess 195 in the plate locates about a stationary location pin 197 (as seen in FIG. 15). The pin 159 then passes arm 164 travelling in a clearance channel 198 and the guide plate disengages from the radial slot 194 before moving along a further tangential portion 200 of peripheral channel 192. The boss 168 and location pins 158, 159 move into alignment so that the location pin 159 is made to move down the tangential portion 200 and into the position of bowling pin 184 as indicated in FIG. 14. Upon further movement of the rotor 162, the location pin 159 moves down portion 200 and the end of plate 156 engages in a further radial slot 202 while the location pin 158 moves along a clearance channel 204 until the bowling pin takes up position 180 as indicated in FIG. 14. Further rotation of the rotor results in moving bowling pins into the positions indicated as 182 and 186 and at this point the rotor is supporting five pins, the first pin received by the rotor being at 186 and the last pin at 188. Once the five pins have been transferred to the setting mechanism 68 (FIG. 1), the distributor is ready to receive pin 190. In practice the distributor receives five pins and then no more pins are received until these five pins are stripped off the distributor by the setting mechanism 68 (FIG. 1).
E. indexing Mechanism
The indexing mechanism is not apparent in FIG. 1 although it will be evident from the foregoing description that the distributor 66 is driven by the indexing mechanism intermittently for picking up pins from the distributor feeding mechanism 60.
Reference is next made to FIG. 14 to describe an indexing mechanism 220. The mechanism includes a pulley wheel 222 driven by a belt 224 from a drive pulley 226. This drive will be more fully described with reference to the drive system. The wheel 222 drives a Geneva mechanism 228 consisting of a spider 230 and slotted wheel 232. The mechanism 228 is conventional in form and is arranged to give discrete movements of one-sixth of a revolution for each movement of the spider through one third of a revolution. A pneumatic actuator 234 can be operated against spring 236 to rotate a latch 238 out of engagement with spider 230 to permit the spider to rotate through 120°. The actuator 234 is operated by the logic circuit as will be described.
The prime purpose of the indexing mechanism is to position each of the arms in sequence for picking up a pin from the distributor feeding system. However, the indexing mechanism also ensures that once the distributor is carrying five pins, the arms are positioned for proper engagement of the pins in the setting mechanism 68 (FIG. 1).
F. setting Mechanism, 68
As seen in FIG. 1, the pin-setting device 50 is mounted on respective side walls 240, 242 or any other convenient support at the sides of the playing surface 52. The device includes a generally horizontal framework 244 supported by feet 246 which rest on the side walls, and respective front and rear support members 248, 250 which extend upwardly from the framework 244 to support longitudinally extending girders 252 which are inter-connected by transversely extending members 254. The distributor 66 is coupled to the girders 252 and members 254 and the clearing mechanism 70 is suspended from support members 248. Setting mechanism 68 is also coupled to support members 248 and as better seen in FIGS. 17 and 18 the setting mechanism is guided by tracks 256, 258 and 260 which combine to provide the necessary motion in stripping pins off the distributor and placing the pins in the desired V formation on the playing surface 52.
Reference is made to FIG. 16 which shows a pin carrier 262 of the setting mechanism 68. The carrier 262 consists of respective forward, intermediate and rear elements 264, 266 and 268 which are interconnected by forwardly extending members 270, 272. A C-shaped pin support 274 is attached to element 264 and similar supports 275, 276, 277, 278 and flanges 280, 282 are attached to respective elements 266 and 268. The pin supports are positioned in the relationship described with reference to FIG. 13 for receiving pins from the distributor 66 (FIG. 1). Each of the C-shaped pin supports opens forwardly so that once the pins are positioned on the playing surface 52 the support can be moved rearwardly out of engagement with the pins and then moved upwardly back into position for receiving further pins. The element 268 has respective upwardly extending flanges 280 and 282 attached to its ends for attachment of the pin carrier 262 to links which move the carrier vertically and maintain the carrier in a horizontal position.
Reference is now made to FIGS. 17 and 18. Pin carrier 262 is guided by structure associated with the tracks 256, 258 and 260 as will be described, and maintained in a horizontal position by first pairs of parallel links 284, 286 (one of each pair being shown in these figures) and second pairs of parallel links 288, 290. Considering one link from each pair, link 284 is pivotally mounted at a first end to a corresponding one of the support members 248 and at its other end to an end of a bell crank lever 292. The link 284 acts as a tie rod whereas link 286 provides the main strength to support the pin carrier and other links. Link 286 is attached by a first of its ends to a shaft 294 and at its other end is pivotally connected to the bell crank lever 292. The arrangement of the links 284, 286 is such that as the link 286 rotates about the axis of shaft 294 the bell crank lever 292 remains in the same position relative to the horizontal. Links 288, 290 are similar in length and attached pivotally at their upper ends to the bell crank lever 292 and at their lower ends to the flange 282 of pin carrier 262. The position and lengths of the links is such that rotation of link 286 about the axis of shaft 294 results in vertical movement of the pin carrier 262 while retaining the pin carrier in a horizontal position.
It will be noted from FIG. 16 that flange 280 differs in shape from flange 282. Although the flanges correspond in that a pair of holes 296 are provided in each flange for pivotally connecting respective pairs of the second links 288, 290, a further pair of holes 298 is provided in flange 280. An elongated arm 300 is attached to flange 280 by fasteners passing through holes 298 and the arm 300 has a roller 302 at its distal end for travelling in tracks 256, 258 to locate the pin carrier 262 horizontally. The arm 300 also has a roller 304 adjacent its lower end for engagement in track 260 when the roller 302 has moved upwardly beyond tracks 256, 258 as will be described.
The pin carrier 262 is movable between an upper position as shown in FIG. 17, an intermediate position shown in chain-dotted outline in FIG. 18, and a lower position shown in full outline in FIG. 18. The pin carrier strips five pins from the distributor by first engaging the pins and then continuing to move upwardly a short distance to take the weights of the pins off the respective shoes 173 of the pick-up mechanisms 154 (FIG. 9). The shoes then move upwardly under the influence of the associated springs thereby freeing the pins. The pins are then supported by the pin carrier 262 so that the pins can now be moved downwardly into contact with the playing surface 52. To this end a crank 306 is attached to shaft 294 and coupled at its distal end to a first pneumatic actuator 308 which is arranged in back-to-back relation with a second pneumatic actuator 310 which is in turn attached to an anchor 312 on one of the girders 252.
Pin carrier 262 is moved into the intermediate position by de-energizing the second pneumatic actuator 310 so that the crank 306 rotates in an anti-clockwise direction as shown in FIG. 17 resulting in downward rotational movement of links 284 and 286. Roller 304 is engaged in track 260 and remains in this track while the pin carrier 262 is moved downwardly into the intermediate position. As will be described with reference to the logic circuit, the pin carrier will remain in this position until a call is made for a new set of pins on the playing surface 52. During this interval the distributor 66 continues to receive pins from distributor feeding system 60.
Once a call is made for a new set of pins on the playing surface 52, the first pneumatic actuator 308 is de-energized and the crank 306 rotates as the pin carrier 262 moves downwardly from the intermediate position until the pins rest on the playing surface 52.
As better seen in FIG. 18 the pin carrier moves down until the pin supports 274 to 278 are out of contact with their respective pins. At this point roller 302 has left track 256 and entered a gate 314 which is better seen in FIGS. 19 and 20. The gate is pivotally mounted on an axle 316 for movement between a first position shown in FIG. 19 and a second position shown in FIG. 20. A small pneumatic actuator 318 is provided and coupled to a bell crank lever 320 having a pin 322 riding in a slot 324 in the gate 314. Bell crank lever 320 is arranged so that the gate 314 cannot be moved out of its preferred positions shown in FIGS. 19 and 20 unless the actuator 318 is energized. In moving the bell crank lever 320, the actuator engages a sensing device 326 which senses when the gate is in the second position shown in FIG. 20, and as will be described, begins the upward movement of the pin carrier 262. As soon as the pin carrier 262 has reached the position shown in full outline in FIG. 18, the gate 314 moves towards the FIG. 20 position thereby moving the pin carrier 262 horizontally and rearwardly so that the pin supports 274 to 278 are no longer positioned under their respective pins. The sensing device 326 is then open and the first pneumatic actuator 308 is energized to rotate the crank 306 and move the pin carrier 262 upwardly. During this upward travel the roller 302 is engaged in the track 258. If the distributor is fully loaded and ready to supply a further five pins to the pin carrier 262, the second pneumatic actuator 310 takes over from the intermediate position and continues to move the pin carrier 262 upwardly into its uppermost position. During this upward travel the roller 302 passes through a biased gate 327 which normally forms part of track 256. The gate permits upward movement of the roller 302 but in the downward path it guides the roller along the track 256. In order to reduce the overall height of the device 50, the track 260 is provided for receiving roller 304 just before roller 302 leaves the upper limit of track 258. Roller 304 then continues to guide the pin setter as it moves into its uppermost position as shown in FIG. 17.
It will now be evident that the tracks 256, 258 and 260 combine to guide both the horizontal and vertical movements of the pin carrier 262 while the links 284, 286, 288 and 290 maintain the carrier 262 in a horizontal position. It should be noted that the setting mechanism 68 (FIG. 1) includes pin carrier 262 but is not coupled directly to the clearing mechanism 70 (FIG. 1) which is operated separately. This permits a relatively simple structure to be employed where previous structures have combined these mechanisms resulting in complex devices which are relatively expensive and difficult to maintain.
In operation, the pin-setting device 50 places five pins on playing surface 52 using the setting mechanism 68. The bowler then attempts to knock down the pins and if he is successful in knocking down only some of the pins, he must clear the pins he has knocked down without disturbing those that he left standing. To this end, a clearing mechanism 70 is provided which is capable of picking up any of the pins that remain standing while the sweeping mechanism 72 removes fallen pins off the playing surface 52. The swept pins then find their way to the elevator 58 and eventually to the setting mechanism 68.
G. clearing Mechanism, 70
As seen in FIG. 1, the clearing mechanism 70 is suspended from the support members 248 and includes a housing 328 in which are mounted pin gripper assemblies 330. Housing 328 is rigidly attached to a pair of upright brackets 332 which are in turn pivotally connected to respective pairs of forwardly extending parallel links 334, 336. The links 334 are pivotally mounted on the support members 248 and links 336 are attached to a shaft 338 rotatably mounted between members 248.
Reference is next made to FIG. 21 to describe the clearing mechanism 70 in greater detail. The links 334, 336 are of equal length and arranged so that when the shaft 338 is rotated, the housing 328 moves vertically while remaining in a generally horizontal position. A crank 340 is attached to the shaft 338 and coupled at its distal end to an upwardly extending pneumatic actuator 342 anchored at 344 to the member 248.
The housing 328 is movable between an upper position shown in chain-dotted outline in FIG. 21 and a lower position shown in full outline. In the lower position the housing engages any pins which remain standing and in the upper position, the housing is sufficiently high that it does not interfere with play and also that it raises pins sufficiently to let the sweeping mechanism 72 pass under the pins for removing fallen pins.
As better seen in FIGS. 1 and 22, the housing 328 is generally V-shaped for engagement with pins placed on the surface by the setting mechanism 68. There are five gripper assemblies 330 attached to a bottom wall 346 of the housing 328. Associated openings 348 are provided in the bottom wall 346 and positioned to be concentric with corresponding pins placed on the playing surface 52 by the setting mechanism 68. The openings are relatively large compared with the neck of the pin to permit the housing 328 to pass over pins which have been moved slightly and not knocked over.
Referring to FIG. 22 and in particular to the gripper assembly associated withh the head pin, each gripper assembly consists of first and second cranked arms 350, 352 pivotally mounted on a common axle 354 attached to the bottom wall 346. Elongated portions of the arms extend over a corresponding opening 348 in the bottom wall and include respective pads 356, 358 for improving frictional engagement with the neck of a pin. When the arms are positioned about the neck of a pin the pads 356, 358 are in substantially parallel arrangement to minimize forces tending to move the pin away from its position on the surface 52. Arm 350 includes a short portion pivotally attached to a block 360 fixed to the body of a small pneumatic actuator 362, and the arm 352 includes a short portion pivotally attached at its distal end to the rod of the pneumatic actuator 362. When the actuator 362 is energized, the pads 356, 358 are drawn towards one another. However, because the whole assembly 330 is free to move about the axle 354, the assembly can pick up a pin from any position within the opening 348. Two positions are illustrated in FIG. 22.
The actuator 362 is double-acting so that it can be energized to move the pads 356, 358 apart until the arms 350, 352 engage respective stops 364, 366. This is the rest position for the gripper assembly 330 and the assembly remains in this position until actuator 362 is energized for picking up a pin as will be described.
As seen in FIGS. 21 and 22, a player has left two pins standing and wishes to clear those pins while the playing surface 52 is swept. As will be described, the player presses a clear button which results in the housing 328 being lowered onto the upright pins until a pad 368 attached to the underside of a top wall 370 of the housing 328 engages the pins to exert a holding force on the pins. The logic circuit then closes the gripper assemblies 330 and those assemblies associated with the upright pins grip the pins so that when the housing 328 is raised the pins go with the assemblies 330. The sweeping mechanism 72 is then energized to sweep the playing surface 52 as will be described.
It will be evident from the description thus far that the setting mechanism 68 and the clearing mechanism 70 are separate and distinct structures which are operable in logical order individually. In order to permit these individual movements, the pairs of parallel links 284, 286 supporting the setting mechanism, and the links 334, 336 supporting the clearing mechanism, are proportional and positioned to provide non-interferring movements of the setting mechanism and clearing mechanism. Also, the shape of the housing 328 permits relative movement between the pin carrier 262 (FIG. 16) and the housing 328 without interference. This arrangement tends to simplify construction and because of the open arrangement of the parts, maintenance is simplified.
H. sweeping Mechanism, 72
As seen in FIG. 1 sweeping mechanism 72 is suspended from framework 244 for sweeping fallen pins off the playing surface 52 and onto the elevator feeding system 54.
Reference is made to FIG. 23 which shows the mechanism 72 in greater detail. The mechanism includes sweeping board 372 coupled to distal ends of a pair of links 374. The links are pivotally connected to respective carriages 376 having rollers 378 adapted to guide the carriages 376 along respective longitudinal rails 380.
Each of the links 374 is pivotally connected intermediate its ends to a respective one of a pair of further links 382, each of which is pivotally connected at its other end to one end of a corresponding one of a pair of bell crank levers 384. Each lever 384 is pivotally mounted intermediate its ends to corresponding carriage 376 and has a roller 386 at its other end adapted to ride on one of a pair of camming surfaces 388 attached to the framework 244. The sweeping board 372 is movable between a forward raised position shown in chain-dotted outline towards the right of FIG. 23, through a guard position shown in full outline and to an end position shown in chain-dotted outline towards the left of FIG. 23. The movement from the raised position to the end position results in sweeping pins off the playing surface 52 and onto the distributor feeding system 54 (FIG. 1).
Each of the carriages 376 is attached to a respective one of a pair of toothed belts 390 which are endless and pass over respective forward and rear pulleys 392, 394 coupled to the framework 244. The shaft carrying pulleys 394 also carries a drive pulley 396 which is coupled by a belt 398 to a smaller pulley wheel 400. The pulleys 396, 400 and belt 398 will be further described under the heading `drive system.`
Carriages 376 are made to move by driving the toothed belts 390 first in one direction to move the board 372 rearwardly and then in the opposite direction to return the board to the forward raised position. The bell crank levers 384, links 382 and links 374 are arranged so that the board 372 is made to move between the guard position and the end position in close proximity to the playing surface 52 and without touching the surface. However, when the carriages 376 move forwardly beyond the guard position the rollers 386 engage the camming surfaces 388 and the bell crank levers 384 rotate in a clockwise direction as drawn in FIG. 23 resulting in the links 374 rotating upwardly about their pivotal connections with the carriage 376. The board 372 then terminates in the forward raised position shown in chain-dotted outline.
When the bowler wishes to sweep the playing surface 52 he presses the aforementioned set button. The board 372 then moves from the forward raised position through the guard position and on to the end position taking the pins with it. Once the board has reached the end position it automatically returns first to the guard position and then to the forward raised position controlled by the logic circuit as will be described. Similarly in response to pressing the aforementioned clear button, board 372 moves to the guard position; waits until the pins have been removed by the clearing mechanism; moves to the end position and returns to the guard position; waits until the pins are again placed on the playing surface; and then moves to the forward raised position. All these movements are controlled by the logic circuit as will be explained.
I. mechanical Operation of Sensing Devices
It is a purpose of this part of the description to introduce the mechanical parts and sensing devices used in the logic circuit and to describe how the pneumatic sensing devices are opened and closed. The functions of the sensing devices will be more positively described in the description of the logic circuit. All of the sensing devices are biased into a closed position in which air can exhaust from the circuit.
As pins are moved vertically by the elevator 58 they meet sensing device 134 (FIG. 6) which takes the form of a simple spring-loaded lever struck by each pin as the pins move vertically. The sensing device 134 therefore senses when a pin passes upwardly towards the distributor feeding system 60. As also seen in FIG. 6, when a pin is moved by the system 60 towards the distributor 66 it passes sensing device 136 which is also of the spring-loaded lever type. This sensing device senses movement of pins along the conveyor 132.
As seen in FIG. 7 a sensing device 142 is positioned so that when a pin is placed in the cup 140, the sensing device 142 is moved. This sensing device senses when a pin is in position in the cup 140.
The shaft 148 shown in FIG. 7 also carries a cam 402 which is better seen in FIG. 24 (adjacent FIG. 7). Upon energizing the actuator 152 the shaft 148 and cam 402 are rotated clockwise with respect to FIGS. 7 and 24. The cam 402 passes over first and second sensing devices 404, 406 as the cam moves upwardly. The striker on sensing device 404 allows the cam to pass without affecting sensing device 404, and the cam then opens spring-loaded sensing device 406. On its way down the cam opens sensing device 404 which is also spring-biased into a closed position.
Reference is next made to FIG. 9 which shows a sensing device 405 for engagement by bosses 168 on each arm as the arm comes into position for receiving a pin from the distributor feeding system 60 (FIG. 1). Pins are fed to the distributor until a sensing device 407 shown in FIG. 14 is struck by pin 186 in the end pin position. Both sensing devices 405 and 407 are spring-loaded for movement into a closed position. Device 407 senses when five pins are in the distributor ready for reception by the setting mechanism.
Reference is next made to FIGS. 17 and 25 (drawn adjacent FIG. 17). As the setting mechanism 68 places pins on the playing surface, the shaft 294 rotates and an arm 408 attached to the shaft engages sensing devices 410, 412, 414 and 416 in sequence. Sensing device 326 previously described with reference to FIG. 19 is spring-biased and is also associated with the setting mechanism. All of the sensing devices 410, 412, 414, 416 are spring-biased to be normally closed and are opened as the arm 408 engages them, with the exception of sensing device 414. This sensing device has a striker which allows the arm 408 to pass over it without actuating the sensing device when the arm moves anti-clockwise (as drawn) and which opens the sensing device when the arm 408 passes in a clockwise direction. A further sensing device 417 is in position for actuation by a cam 419 on shaft 294 for ensuring that the pins are placed gently on the playing surface as will be described.
As seen in FIGS. 21 and 26, shaft 338 of the clearing mechanism 70 has an arm which engages sensing devices 420, 422 as the arm rotates to raise and lower the clearing mechanism 70. However, sensing device 422 is opened only when the arm 418 is moving in a clockwise direction (as drawn) corresponding to the housing 328 being raised. Both sensing devices are spring-biased into a closed position.
As seen in FIGS. 1 and 27, which are adjacent FIG. 1, carriage 376 includes a striker plate 424 for contacting sensing devices 425, 426 and 427 suspended from the framework 244 to sense movements of the sweeping mechanism 72.
Reference is next made to FIG. 28 which shows an optional arrangement used to ensure that the setting mechanism and other mechanisms will not move under the influence of gravity when air pressure is not available. To this end a latch 428 is pivotally suspended from girder 252 and is connected to a spring 430 which biases the latch into engagement with a pin 432 on link 286 (see also FIG. 17). A second latch is suspended behind latch 428 from a common shaft 434 to engage with a pin 436 on one of the upright brackets 332 of the clearing mechanism 70 (FIG. 21). Thus when both the setting mechanism 68 and the clearing mechanism 70 are in their raised positions, the latches 428 can engage respective pins 432 and 436 to hold these mechanisms in the raised position. As soon as air pressure is restored a small pneumatic actuator 438 applies a force to a crank 440 attached to shaft 434 to disengage the latch 428. The crank 440 is moved around into engagement with an electrical switch 442 to supply electrical power to an electric motor which provides the motive power for the drive system.
J. drive System, 74
Reference is now made to FIG. 1. The elevator feeding system 54, elevator 58, distributor feeding system 60, distributor 66 and indexing mechanism, and sweeping mechanism 72 are driven by belts from a single power source. Power for all other movements comes from pneumatic sources which may be external to the device 50 or also driven from the power source. As seen in FIG. 29, a power source 444 in the form of an electric motor drives a main shaft 446 through reduction pulleys 448 and a belt 450. Drives to the various mechanisms and systems are taken off shaft 446.
Reference is next made to FIG. 29 in conjunction with FIG. 2 to describe the drive to the vibrator 76. A pulley 452 rotates in a transverse plane and drives a long belt 454 past a pair of idler pulleys 456, 458 arranged at right angles for tensioning the belt on the pulley 452 and on a pulley 460 rotating in a longitudinal plane. The pulley 460 is coupled to eccentric drive 82 through further pulleys 462, 464 associated with belt 466. The main shaft 446 is driven continuously so that the eccentric drive 82 also moves continuously while the pin setting device 50 is in use.
Reference is next made to FIGS. 3, 4 and 29 to describe the drive to the transverse conveyor 92, longitudinal conveyor 94 and elevator 58. As previously described with reference to FIG. 4, belt 122 drives the elevator and as seen in FIG. 29 this belt passes around a tensioning pulley 468 and drive pulley 470 attached to a shaft 472. Drive to shaft 472 is provided from the main shaft 446 by way of reduction pulleys 474 connected by a belt 476 to drive a secondary shaft 478. Thiss shiaft is driven continuously and has a pneumatic clutch 480 controlled by the logic circuit for coupling a pulley 482 to the shaft 478 as required. When the pulley 482 is connected to shaft 478, it drives a belt 484 which is engaged about a further pulley 486 on shaft 472 to drive shaft 472 and hence the elevator. Belt 484 is tensioned by an idler pulley 488.
Pulleys 490, 492 are also attached to the shaft 472, the former for driving belt 494 and pulley 496 and hence transverse conveyor 92, and the latter for driving the longitudinal conveyor 94 by way of pulley belt 498 and associated pulleys 500. The belt 498 is looped under the pulley 500 and an idler 501, and then up to an idler pulley 502 to transmit the drive through 90°. Because the transverse conveyor 92, longitudinal conveyor 94 and elevator 58 are driven from the same pulley 482 associated with clutch 480, these parts stop and start together and move at a substantially constant relative velocity.
Reference is next made to FIGS. 6 and 29. The pin transporting conveyor 132 associated with the distributor feeding system is driven from secondary shaft 478 by belt 504 passing about associated pulleys 506. As a result the conveyor 132 moves continuously but will not receive pins from the elevator when the elevator is stopped by the clutch 480 as will be described under the heading `logic circuit.`
As seen in FIGS. 14 and 29, the rotor 162 of the distributor is driven by Geneva mechanism 228 (FIG. 14) which is in turn driven from secondary shaft 478 through friction clutch 508, belt 510 and associated pulleys 512, and then by the belt 224 and associated pulleys 222 and 226. The arrangement is such that the clutch 508 exerts a driving force continuously to drive belts 510 and 224. However, the Geneva mechanism allows only periodic movement to ensure proper location of the arms for picking up pins from the distributor feeding system so that the clutch slips while the Geneva mechanism holds the arms stationary.
Reference is again made to the main shaft 478 of FIG. 29. The shaft 478 carries a pair of pneumatic clutches 518, 520 arranged back-to-back for controlling the direction of movement of a belt 522 which passes around an idler pulley 524 and a pulley 526 mounted on a shaft 528 at right angles to main shaft 446. The arrangement is such that when the pneumatic clutch 518 is energized the belt 522 moves in one direction and then when the other clutch 520 is energized in place of the clutch 518, the belt 522 moves in the opposite direction. As previously described with reference to FIG. 23 a toothed belt 398 combines with pulleys 400 and 396 to transmit torque from the shaft 528 to rear pulleys 394 associated with the sweeping mechanisms 72. A brake wheel and brake assembly 527 is coupled to the shaft 528 and operated pneumatically by the logic circuit to bring the sweeping mechanism to a positive stop.
It will now be evident that the arrangement of belts shown in FIG. 29 permits the pin-setting device 50 (FIG. 1) to be driven from a single power source 444.
K. logic Circuit and Operation of Pin Setting Device, 50
For the purposes of describing the logic circuit shown diagrammatically in FIG. 30, it will be assumed that initially the device has pins only in the elevator feeding system where there are a minimum of 10 pins. As will be described, the device is intended to function with at least 10 pins although preferably 12 or 13 pins are used. Assume also that initially the pin-setting device 50 is not switched on and that pneumatic pressure is not available.
For simplicity of description the pin-setting process will be described under a series of headings which assume that the device is first switched on and that air pressure applied. A player then sets five pins, clears some pins and then finally resets a further five pins.
K. (a) Sequence Requirements
The logic circuit ensures the proper order of events in receiving pins off the playing surface and eventually resetting the pins on the playing surface.
As seen in FIG. 1, pins are moved vertically by the elevator 58 from the elevator feeding system 54 and passed to the distributor feeding system 60. Because the distributor requires only five pins at a time, it is essential to ensure that the system 60 operates only when pins are required at the distributor 66. Consequently, the elevator and distributor feeding systems 60 must be controlled so that they operate only when pins are required at the distributor and stopped when pins are not required. Once the distributor has received five pins it is controlled by the logic circuit so that it stops and holds the pins until they are removed from the distributor by the setting mechanism 68.
Setting mechanism 68 is controlled with respect to a player's requirements in the sense that it will not place five pins on the playing surface unless required to do so by a player.
The pin-setting device 50 must also be capable of ignoring player requests either to operate the setting and clearing mechanism simultaneously or to ignore requests for activating one of the mechanisms when the other is already in operation. Also, the sweeping mechanism 72 must be controlled in relation to the clearing mechanism for removing fallen pins once the clearing mechanism picks up upright pins. Similarly, when five pins are being placed on the playing surface by the setting mechanism 68 the board of the sweeping mechanism 72 is placed in the guard position so that a player cannot send a ball down the playing surface to collide with the setting mechanism.
If all of the pins are on the elevator feeding system 54 initially, the first five pins to reach the distributor will be stored in the distributor whereupon the elevator must be stopped to prevent a blockage of pins on the distributor feeding system 60. The sixth and seventh pins open sensing devices resulting in the elevator and elelator feeding system stopping to prevent a build up of pins in the distributor feeding system. The setting mechanism 68 then strips five pins from the distributor. Next the sixth to 10th pins are fed into the distributor whereupon the 11th and 12th pins have the same effect as did the sixth and seventh pins.
When the player presses a set the requiring that five pins be placed on the playing surface, the setting mechanism lowers five pins onto the playing surface and returns upwardly either to the intermediate position, or if the distributor is full, to the upper position to strip a further five pins off the distributor. The distributor feeding system and elevator then begin to move again for feeding pins onto the distributor. Once the player has disposed of the pins on the playing surface they find their way up to the distributor again and while this is taking place the five pins stored in the setting mechanism are available for placing on the playing surface.
The pin-setting sequence will now be described in greater detail with reference primarily to FIG. 30.
K. (b) Swtich On
The pin-setting device relies for operation on a supply of compressed air which provides pressures of 60 pounds per square inch and 90 pounds per square inch. In general, the 60 pounds per square inch supply is used in the sensing devices and the 90 pounds per square inch is used in power valves which control air supply to the various pneumatic actuators. The power valves are of the spool type and are unbiased, i.e., have no preferred position. The power valves also include provision for a plurality of pilots each of which is responsive to a signal to move the spool. The logic circuit also uses a plurality of control valves which are also of the spool type. Some control valves are biased towards a preferred position and others are unbiased. The biased type includes a spring drawn diagrammatically in the valve.
The terminology "control valve" and "power valve" is used to aid in identifying the valves of FIG. 30. Headings at the top of this figure indicate where the various valves and sensing devices are positioned in the logic circuit.
Once air pressure is supplied to the device 50, the sensing devices and power valves will be in the positions shown in FIG. 30 ready for operation of the device. References to the left of FIG. 30 indicate where the pneumatic sensing devices appear in the pin-setting device 50.
Initially, the sensing devices in the distributor feeding system are closed so that air cannot pass through them. Similarly, sensing device 407 in the distributor is in a closed position and below that sensing device 405 is in an open position so that pressure passes through this device and then meets a closed sensing device 142 in the distributor feeding system.
The setting mechanism 68 is in the intermediate or storage position so that sensing device 412 is open permitting air to pass through the device before the air eventually meets closed sensing devices. The clearing mechanism sensing devices are also closed and in the sweeping mechanism the sensing device 425 is open indicating that the sweep board is in the forward raised position. Pressure available through this sensing device has no effect on the circuit at this time because of the position of the subsequent sensing devices. However, it should be noted that pressure from sensing device 425 is available at a pilot of power valve 529 which controls air to actuator 438 previously described with reference to FIG. 28.
Returning for the moment to the remainder of the pneumatic sensing devices associated with previously described parts of the pin-setting device, the sensing devices at the player controls are closed at this time. Consequently the pin-setting device will not operate if a player presses either a set button on sensing device 530 or a clear button on sensing device 532 because no pressure is available to these sensing devices until a pneumatic sensing device 534 is operated electrically from the management control position. Upon operating the sensing device 534 line pressure of 90 pounds per square inch is available at a pilot of power valve 529 resulting in a differential pressure of 30 pounds per square inch across the valve to open the valve. 90 p.s.i. air is then available at pneumatic actuator 438. Air from sensing device 534 is also available at a pilot of control valve 548 to switch this valve and allow 60 p.s.i. air from sweep sensing device 425 to reach the control sensing devices 530, 532.
As previously described with reference to FIG. 28, actuator 438 releases latch 428 and closes switch 442 to supply electrical power to motor 444 (FIG. 29).
It will be evident from an inspection of the 90 p.s.i. supply that as soon as the pressure is applied the pneumatic pressure is available at the clearing mechanism actuator 342 previously described with reference to FIG. 21. Pressurized air reaches the actuator 342 by way of a power valve 536 which is in the open position. The actuator 342 ensures that the clearing mechanism is in the raised position at this stage.
Following the 90 p.s.i. line further down FIG. 30, 90 p.s.i. air passes through a power valve 538 to reach the actuator 362 for holding the gripper assembly in an open position as described with reference to FIG. 22. As a result the clearing mechanism is ready to be lowered for engaging upright pins. The valve 538 is a four-way valve having a single spool.
Also connected to the 90 p.s.i. supply is a power valve 540 supplying compressed air to actuator 308 previously described with reference to FIGS. 17 and 18 for maintaining the setting mechanism in its intermediate position.
The last direct 90 p.s.i. air connections are to sensing device 416 and power valve 529 which are both closed so that no air passes.
Consider now direct 60 p.s.i. connections bypassing the sensing devices previously discussed. There are two such connections at the bottom left of FIG. 30 and one along the top of this figure. The upper of the bottom connections feeds air through a control valve 542 and the power valve 544 to actuator 152 (FIG. 7) for ensuring that cup 140 is in its lower position ready to receive a pin. Valve 544 is similar to valve 538.
The lower of the bottom 60 p.s.i. connections leads through a power valve 546 to pneumatic clutch 480 (FIG. 29) to complete a drive system from motor 444 to the elevator and elevator feeding system.
The top 60 p.s.i. connection leads directly through a power valve 547 to brake 527 previously described with reference to FIG. 27 so that the sweep mechanism is positioned positively. The valve 547 is similar to valve 538.
Summarizing the "switch on" sequence thus far, the device is positioned ready to begin setting pins and ins is in operation to move pins to the distributor. When the distributor and setting mechanism each contain five pins, the elevator and the conveyors of the elevator distributor feeding system will stop. However, the motor and eccentric drive 82 (FIG. 29) will continue to operate. The player cannot use the set and clear buttons effectively until the manager's control sensing device 534 is opened to energize actuator 438 thereby releasing the setting and clearing mechanisms as previously described.
Opening the manager's control sensing device 534 applies 90 p.s.i. air to a pilot of a control valve 548 to open this valve so that 60 p.s.i. air reaches the player controls by way of sweep sensing device 425 and control valve 548.
A manual switch 550 is provided for opening a pneumatic sensing device 552 for bypassing the management control sensing device 534. Device 552 permits a maintenance mechanic to operate the pin-setting device 50 without relying on management to operate sensing device 534. Unlike sensing device 534, air from sensing device 552 is not available at the player controls so that the mechanic has sole control over the pin-setting device.
It will now be evident that once the 60 p.s.i. and 90 p.s.i. air pressures are supplied to the pin-setting device 50, the actuators necessary for maintaining the mechanisms in the required positions are pressurized. Also upon opening the manager's control sensing device 534, the latch 428 described with reference to FIG. 28 permits movement of the clearing and setting mechanisms as required.
K. (c) First Pin
Consider now the situation in which all of the pins in the pin-setting device 50 are in the elevator feeding systen 54, and air and electrical power is supplied to the device. As a result pins begin to move through the elevator and distributor feeding system and onto the distributor.
The first pin to find its way onto the elevator 58 (as seen in FIG. 6) strikes sensing device 134 of the distributor feeding system thereby opening this device momentarily. As a result pressure is available at an unbiased control valve 554 which is in a closed position so that the pressure goes no further. As the pin continues in its path towards the distributor it strikes sensing device 136 and opens this device so that pressure is available at a pilot of control valve 554 thereby opening this valve. However, at this point the sensing device 134 is closed so that no pressure passes through control valve 554 which remains in the open position.
As the pin continues towards the distributor it is positioned in cup 140 (FIG. 7) where it strikes sensing device 142 and opens this device. If an arm of rotor 162 (FIG. 9) is in position to receive a pin, the sensing device 405 is opened and airr passes from sensing device 405 to device 142 and on to a pilot of a power valve 544. The air then moves the power valve allowing 60 p.s.i. air to move actuator 152 thereby raising the pin towards the distributor as previously described with reference to FIGS. 7 and 8.
As previously described with reference to FIGS. 7 and 24, as the pin is raised by actuator 152 cam 402 engages a striker on sensing device 404 which is not actuated because of the design of the striker. The cam then engages and opens sensing device 406 before returning to open sensing device 404 as the cam passes to its original position. The effects of opening and closing the sensing devices 404 and 406 will now be considered with reference to the logic circuit.
When the sensing device 406 is opened as the cam 402 moves upwardly, 60 p.s.i. air is made available at a pilot of power valve 544 to return the spool of this valve to its original position. Air then passes by way of valve 544 to actuator 152 to return the cup 140 to its lowermost position as shown in FIG. 7. The cam 402 (FIG. 24) then returns to its original position thereby momentarily opening sensing device 404 so that air is made available firstly at a pilot of power valve 544 to return the spool of this valve to its original position, then at a pilot of power valve 546 where it has no effect, and finally at actuator 234 (FIG. 14). Upon momentarily energizing the actuator 234, the Geneva mechanism 228 permits the drive system to rotate the rotor 162 through 60° to bring the next arm 164 into position for receiving a pin from the distributor feeding system. In doing so a boss 168 (FIG. 9) strikes sensing device 405 which has closed in the interval between the preceeding boss 168 striking the sensing device 405 and the boss 168 shown in FIG. 9 reaching the sensing device 405. Upon opening the sensing device, air is again available at sensing device 142 so that if a second pin were positioned in the cup 140 (FIG. 7) the actuator 152 would again be energized for delivering the second pin to the distributor. It will be evident that the actuator 152 will only deliver a pin if called upon to do so by opening sensing device 405. Also, if the actuator does not elevate the first pin, the valve 554 which was opened by the first pin will remain in this position so that when the next pin opens sensing device 134, air is available through control valve 554 to switch power valve 546 and allow air in clutch 480 to exhaust thereby stopping the elevator and distributor feeding system. However, as soon as the actuator 152 delivers a pin, the sensing device 404 will be opened and air will be applied both to the pilot of control valve 554 to reset this valve and also to the pilot of power valve 546 to open this valve for supplying air to the clutch 480.
The first pin is now in position in the distributor and the next arm of thee distributor awaits a pin. The process is repeated for each pin until sensing device 407 shown in FIG. 14 is struck by the first pin indicating that the distributor now contains five pins. Opening of sensing device 407 by the first pin results in 60 p.s.i. being applied to a pilot of control valve 558 to open this valve. As a result air available through sensing device 412 and a control valve 560 passes through valve 558 and on to open a power valve 562. 90 p.s.i. air is then available at actuator 310 previously described with reference to FIG. 17. Consequently pin carrier 262 of the setting mechanism (FIG. 16) is raised to its uppermost position for stripping the first five pins off the distributor rotor 162. This stripping movement affects sensing devices 410 and 412 (FIG. 25) as will be described.
Returning to the effect of opening sensing device 407, 60 p.s.i. air is also available from device 407 at the pilot of control valve 542 to close this valve. As a result 60 p.s.i. air is no longer available at power valve 544 for energizing actuator 152 (FIG. 7). Now the cup 140 is empty and there are five pins in the distributor. As a result the clutch 480 must be stopped to prevent a pileup of pins near the cup. Consider the next pin to come up the elevator. This pin strikes sensing device 134 and air passes through device 134 ending at control valve 554. Next, the pin strikes sensing device 136 which causes control valve 554 to open. As soon as a further pin strikes the sensing device 134, air passes through control valve 554 and on to a pilot of power valve 546 to close this valve and cut off air from pneumatic clutch 480. As a result the elevator and elevator feeding system stop. The 11th pin is now in the cup 140 and the 12th pin is in the elevator adjacent the distributor feeding system. No further pin movement will take place until the setting mechanism strips the pins off the distributor and allows sensing device 407 (FIG. 14) to close whereupon pressure is no longer applied to the control valve 542. However, before the distributor will again receive pins from the distributor feeding system, the setting mechanism must indicate to the logic circuit that it has received five pins from the distributor and has them in the intermediate position of the pin carrier as shown in chain-dotted outline in FIG. 18.
K. (d) Loading the Setting Mechanism With the First Five Pins
As previously described with reference to FIG. 25, the arm rotates for opening the sensing devices 410,412,414 and 416. Sensing device 410 is opened when the setting mechanism is in its uppermost position; sensing device 412 is opened when the setting mechanism is in its intermediate position; sensing device 414 is opened when the mechanism is travelling upwards towards the intermediate position; and the sensing device 416 is opened when the setting mechanism is at its lowermost position. In the position shown in FIG. 30, the arm 408 is in contact with sensing device 412 and holds it in an open position.
As previously described, when the sensing device 407 of the distributor is open, air is available at the actuator 310 so that the pin carrier 262 moves upwardly to strip pins from the distributor. In doing so, the arm 408 leaves sensing device 412 so that this device then closes thereeby cutting off air from beyond the device. Upon opening device 410, air is made available initially at a pilot of control valve 560 to switch this valve. However, because device 412 is closed no air passes through control valve 560. Air from sensing device 410 also reaches a pilot of power valve 562 to close this valve and allow air to exhaust from actuator 310. The weight of the setting mechanism and pins then causes the mechanism to move downwardly carrying the five pins with it until the mechanism reaches the intermediate position where all of the air is exhausted from actuator 310 and sensing device 412 is again opened.
K. (e) Fifth to Tenth Pins
The setting mechanism is now in the intermediate position and there is a pin in the cup 140 and a further pin in the elevator adjacent the distributor feeding system. The elevator is stationary and before further pins can be elevated to the distributor, the control valve 542 must be returned to the open position as shown in FIG. 30. This is done by air from sensing device 412 which was opened when the setting mechanism returned to the intermediate position. This air is fed both to a pilot of a control valve 564 to open the valve and also to an inlet of the valve so that once the valve is opened air from device 412 passes through valve 564 and to a pilot of control valve 542 to open this valve. Air fed to valve 564 is also available at a bleed valve 566 which allows air to build up a pressure at a second pilot of control valve 564 so that eventually the air pressures on each side of the spool of this valve are equalized and the spring in the valve returns the valve to the closed position. Control valve 542 is now open and air is available at actuator 152 for elevating pins. The sixth pin is then elevated to the distributor whereupon the sensing device 406 (FIG. 24) is again opened by elevation of the pin to the distributor and air from sensing device 406 switches the power valve 544 into position for moving actuator 152 to lower cup 140 (FIG. 7) downwardly for receiving a further pin. As the cup moves downwardly the sensing device 404 is opened so that air pressure closes control valve 554, then opens power valve 546 to supply air to the clutch 480 and finally supplies air to the actuator 234 of the Geneva mechanism. Once the clutch 480 is operated, the elevator and distributor feeding system are again powered for moving pins towards the distributor.
We now have a situation which the setting mechanism is in its intermediate position carrying five pins and a further five pins are being fed to the distributor. When the first five pins were ready in the distributor the setting mechanism automatically picked up the pins. However, because the setting mechanism already has five pins the logic circuit must ensure that the setting mechanism does not attempt to move a further five pins from the distributor before first placing pins one to five on the playing surface.
Returning to sensing device 410, when this device was opened by the setting mechanism removing the first five pins, the control valve 560 was switched into the dotted position shown in FIG. 30. The valve 560 remained in this position so that when the sixth pin opens sensing device 407 (FIG. 14) indicating that a further five pins are available in the distributor, air is not available from control valve 560 for passing through control valve 558 to energize actuator 310. The pin movements described have taken place because air and power have been applied to the device. Before a player has control the manager's sensing device must be opened. Then the setting mechanism which would otherwise remain in the intermediate position is ready to lower pins on to the playing surface in response to a signal from the sensing device 530 associated with the set button.
When pins five to ten have been placed in the distributor, pins 11 and 12 when elevated have the same effect on the setting device 50 as did the pins six and seven. As a result the elevator and elevator feeding system are stopped with pin number 12 near the top of the elevator.
K. (f) Effect of Set Button -- First Call
Consider now the effect of pressing the set button to open the sensing device 530 which receives 60 p.s.i. air by way of sweep sensing device 425 and control valve 548 after the manager's control sensing device 534 is opened. Once the set button has been pressed it is desirable that the sweep mechanism should operate firstly to sweep off the playing surface and then to return to the guard position while the setting mechanism places five pins on the playing surface. Once the pins are in place, the setting mechanism then moves upwardly either to the intermediate position or its uppermost position to receive a further five pins from the distributor and the sweeping mechanism moves to the forward raised position.
Consider now the logic circuit and the result of operating the set button to open device 530. Initially air is supplied to a pilot of power valve 547 to move the spool into the position shown in dotted outline. As a result air from the 60 p.s.i. supply which formerly was fed to the brake 527 is now fed to clutch 520 by way of a power valve 568. The brake 527 is now released and the sweep board 372 (FIG. 23) is driven rearwardly as the clutch 520 is engaged. (See also FIG. 29).
When the set button device 530 is opened, air is also supplied to a pilot of control valves 570 and 572 to switch these valves so that air which was formerly available at sweep sensing device 426 is now cut off. Also, as soon as the sweep mechanism begins to move, the sweep sensing device 425 closes and cuts off air from a shuttle valve 573. This valve is of a type having two inlets and one outlet for controlling flow from either inlet and through the outlet. Up to this point the valve has had no function in the logic circuit.
The sweep mechanism continues to move past the guard position corresponding to sensing device 426 until sensing device 427 is closed. At this point 60 p.s.i. air passes through sensing device 427 to a pilot of control valve 570 to switch this valve back to its original position and provide air at sweep sensing device 426 which is now again closed. Air from sensing device 427 also passes to a pilot of power valve 568 to switch this valve so that air which previously was intended for clutch 520 now finds its way to clutch 518 to reverse the direction of the sweeping mechanism. Air from sensing device 427 is also fed to a pilot of a control valve 574 to switch this valve.
The sweeping mechanism is now travelling forwards after having cleared the playing surface of fallen pins. It is desirable that the sweep board stops in the guard position while the setting mechanism is lowered to place pins on the playing surface.
As the sweep board travels towards the front of the device, it opens sweep sensing device 426. 60 p.s.i. air from control valve 570 then passes to sensing device 426 and on to shuttle valve 573 and control valve 572. However, the control valve 572 was switched to the dotted position when the set button was pressed so that the air from sensing device 426 passes to a further control valve 576 opening this valve.
Air pressure from sensing device 426 available at shuttle valve 573 switches the spring-loaded control valve 578 so that air from the same source momentarily passes through this valve for a predetermined time interval set by the time taken for air pressure to equalize in the control valve 578 by way of a bleed valve 580. Air pressure from control valve 578 is fed to a pilot of power valve 547 thereby returning this valve to its original position so that 60 p.s.i. air is again applied to the brake 527 to positively stop the sweep mechanism. At the same time power valve 547 cuts off air from the clutches 518 and allows the pressure in the system to exhaust so that the clutch is no longer engaged.
With the board of the sweeping mechanism in the guard position, the setting mechanism can now place pins on the playing surface. Returning now to control valve 576 (which was switched when the sweeping mechanism returned to the guard position and opened sensing device 426), air is available at valve 576 through valve 560 previously closed when the setting mechanism returned to the intermediate position with five pins in place. As a result air from sensing device 412 passes through control valves 560 and 576 before moving a pilot on power valve 540 to switch this valve and allow pressurized air from actuator 308 to exhaust to atmosphere through a device 549 which is held open until the setting mechanism has almost reached its lowermost position. At this point the biased device 549 is allowed to close so that air from actuator 308 must bleed relatively slowly through a restriction 551 to ensure that the pins are placed gently on the playing surface.
Reference is next made to FIGS. 25 and 30. When the setting mechanism is lowered, the sensing devices which are affected are the sensing device 414 between the intermediate and lower position and sensing device 416 corresponding to the lower position. Initially device 412 is open having been closed and opened again when the setting mechanism returned to the intermediate position after picking up pins from the distributor. As the setting mechanism is lowered sensing device 412 is first closed and then arm 408 passes over device 414 without affecting this device due to the type of striker used with the device. When the arm reaches sensing device 416 this device is opened so that 90 p.s.i. air originating with the 90 p.s.i. vertical line passes through sensing device 416 and on to actuator 318 previously described with reference to FIGS. 19 and 20 for moving gate 314. As the actuator 318 moves it opens sensing device 326 shown in FIGS. 19 and 20 so that 60 p.s.i air passes through this device and divides firstly to operate a pilot to return control valve 560 to its original position so that more pins can be stripped off the distributor and secondly to close switch 555 and to move a pilot of power valve 540 to return this valve to its original position. As a result 90 p.s.i. air is again available at actuator 308 to raise the setting mechanism back to its intermediate position. Switch 555 is included to give a signal at a counter which indicates to management how many times the device has set five pins.
As the setting mechanism begins to move upwardly, arm 408 (FIG. 25) releases sensing device 416 and air is no longer available at actuator 318 so that the spring in the actuator returns the gate to the position shown in FIG. 19 and the sensing device 326 is again closed. As the setting mechanism continues its upward path, the sensing device 414 is opened so that 60 p.s.i. air is available at a pilot of power valve 547 and air is again available at clutch 518 by way of power valve 568 which remains in the dotted position. The clutch then engages and the sweep board begins to move from the guard position to the forward raised position.
Ignoring the movement of the sweeping mechanism for the moment, the arm 408 (FIG. 25) then reaches sensing device 412 and upon opening this device, air again is available for operating the setting mechanism and associated valving as previously described when the setting mechanism moved upwardly for receiving pins from the distributor. If the distributor has a further five pins the sensing device 407 will be open and air available at control valve 560 previously returned to the original position when sensing device 326 was opened. As a result the setting mechanism will continue upwardly past the intermediate position to the upper position to strip pins off the distributor. However, if the distributor does not contain five pins the sensing device 407 will be closed and the setting mechanism will remain in the intermediate position until sensing device 407 is again opened indicating that five pins are available. These pins will then be stripped off the distributor by the setting mechanism and returned to the intermediate position ready for placing on the playing surface.
The board of the sweeping mechanism was described as beginning to move into its forward raised position and description of this movement will now be completed. As the board moves upwardly the sweep sensing device 425 is opened so that 60 p.s.i. air is again available at the player controls. This air supply was suspended so that a player could not actuate either the set button or the clear button during operation of the setting mechanism. Also, 60 p.s.i. air is available at a pilot of power valve 568 resulting in air being exhausted to de-activate clutch 518 and stop the sweep mechanism. To this end air also passes through shuttle valve 573 and as previously described provides a pulse through valve 578 for switching power valve 547 to its original position so that connections to both clutches 518 and 520 lead to exhaust ports. After each application of air to valve 578, the air exhausts quickly through a one-way valve 553.
The device has now placed five pins on the playing surface and the sweeping mechanism is in its forward raised position so that a player can roll a ball at the five pins. If the player knocks down all five pins he will press the set button and the previously described sequence will be set in motion resulting in a further five pins being placed on the playing surface. However, if the player knocks down some of the pins and leaves others standing, he will wish to clear the playing surface of the fallen pins. In this event he will press the clear button to open sensing device 532 and the resulting sequence will now be described.
K. (g) Clearing Mechanism and Clear Button
When a player presses the clear button to open sensing device 532, he connects 60 p.s.i. air to the pilot of power valve 547 so that the air is available at clutch 520 for driving the sweep mechanism rearwardly and the brake 527 is released. The clear button device also supplies 60 p.s.i. air to a pilot of control valve 572 to switch this valve back into its original position. Also, because the sweep board has begun to move from the forward raised position driven by clutch 520, air is no longer available through sweep sensing device 425 at shuttle valve 573 and control valve 578. As the sweep mechanism continues its movement towards the guards position it opens the sweep sensing device 426 so that air is available by way of control valve 570 and sensing device 426 at the shuttle valve 573 and hence at the control valve 578. As before, this results in a pulse of 60 p.s.i. air at the pilot of power valve 547 to move the spool of this valve resulting in the brake 527 being applied and the clutch 520 being disengaged. The sweep mechanism is then in the guard position where it will remain until the clearing mechanism has lifted up the upright pins.
Some of the air which passes through sensing device 426 passes to control valve 572 and hence through a spring-loaded control valve 582 and bleed valve 584 (which are similar to valve 578 and 580) to a pilot of power valve 536 to switch this valve and allow pressurized air in actuator 342 to exhaust to atmosphere. As previously described with reference to FIG. 21, the clearing mechanism then moves to a lowermost position for picking up pins fromm the playing surface. The control valve 582 and bleed valve 584 combine to provide a pulse of air at the pilot of power valve 536 sufficient to switch the valve.
As seen in FIGS. 21 and 26, as arm 418 moves upwardly (corresponding to a downward movement of the clearing mechanism) it first passes over sensing device 422 which because of the striker on this device is unaffected and then reaches sensing device 420 when the clearing mechanism is at its lower position. Upon opening sensing device 420, 60 p.s.i. air is applied by way of control valve 574 to a pilot of power valve 538 for switching valve 538 so that air is supplied to gripper actuator 362 which as seen in FIG. 22 results in picking up the upright pins.
60 p.s.i. air also passes from sensing device 420 through a bleed valve 586 which permits a gradual pressure build up at a pilot of valve 536 to supply air to actuator 342 for returning the clearing mechanism to its upper position. (The purpose of this delay will be described later.) As a result 90 p.s.i. air is again available at actuator 342 to raise the clearing mechanism containing the pins which the player failed to knock down.
As soon as the clearing mechanism begins to travel upwardly the sensing device 420 closes cutting off air from bleed valve 586. Air trapped between valve 586 and power valve 536 can exhaust quickly through a one-way valve 587. Eventually sensing device 422 is opened and air then passes through sensing device 422 to pilot of power valve 547 resulting in 60 p.s.i. air being applied to the clutch 520 and removed from the brake 527. The sweeping mechanism then continues its travel rearwardly to remove fallen pins while the clearing mechanism is in its upper position. The sweeping mechanism moves in a similar manner to that previously described when describing the setting mechanism. In this case however, when the sweeping mechanism is at its rearmost or end position and the sensing device 427 is closed, air is applied to control pilot of valve 574 to switch this valve into the dotted position. As a result when the sweeping mechanism returns to the guard position and air passes through control valve 570, sensing device 426, control valve 572 and pulse control valve 582, the power valve 536 is switched to allow pressurized air to bleed from the actuator 342 to atmosphere. The clearing mechanism then falls under its own weight back to the lower position.
As the clearing mechanism falls, the sensing device 420 is opened so that 60 p.s.i. air passes through the control valve 574 (which was previously switched) to a pilot of power valve 538 to switch this valve into the dotted position resulting in the actuators 362 moving to release the pins (see also FIG. 22). The pins which the player failed to knock down have now been returned to the playing surface.
Air from sensing device 420 also passes through bleed valve 586 which again gradually allows a pressure build up at a pilot of valve 536 to supply air to actuator 342 for returning the clearing mechanism to its upper position. The bleed valve 586 provides sufficient delay to ensure that the gripper mechanisms release the pins before the actuator 342 is energized. In moving upwardly, the clearing mechanism causes arm 418 to open sensing device 422 so that air is again applied to the clutch for returning the sweeping board to its forward raised position. The one-way valve 587 allows rapid exhaust of air.
This completes the clearing sequence for lifting and replacing pins which were not knocked down, and for sweeping fallen pins off the playing surface. Once the player has completed his turn by either knocking all of the pins or simply using three balls, he presses the set button and as previously described a new set of five pins is placed on the playing surface.
It will be evident from the foregoing description that when a player presses either the set button or the clear button the sweep mechanism is placed in the guard position so that if the player rolls a ball on the playing surface the mechanism is protected from impact witth the ball. Also, air for the set button and the clear button is provided through the sweep sensing device 425 which opens as soon as the sweep mechanism moves from the forward up position. As a result air is no longer available at the player controls so that the player cannot interfere with the sequence once he has initiated a particular movement.
This completes the description of the logic circuit and of the pin setting device 50. It will now be evident that the device is of relatively simple design having a single prime mover providing power to all rotating parts and that other parts of the device are moved by pneumatic actuators controlled by a logic circuit. The device is relatively safe to service because of the low power required and because of the impressibility of air. For instance, if a service mechanic were to have the setting mechanism or clearing mechanism move down trapping a part of his body he is unlikely to be injured seriously because these parts are moving under the influence of gravity. Also, when the mechanisms move upwardly air in the actuators moving the mechanisms is compressible so that the mechanic would probably be uninjured and able to free himself by applying a force to move the mechanism away from the trapped part of his body.
A further advantage of the present invention is that because the setting mechanism and clearing mechanism are separate and distinct parts linked only by the logic circuit, servicing of the mechanisms is simplified. A mechanic can operate each of the mechanisms individually and test them so that he is able to pinpoint faults more positively and quickly.