INTERVAL TIMER MECHANISM
United States Patent 3591956
An interval timer with an audible or electrical output has a springwound motor driving a control cam which governs the output mechanism, whereby to enable operation upon the completion of time intervals of irregular duration. A blocking member obstructs movement of the control cam follower to prevent any output if the mainspring is not fully wound.
US Patent References:
Alarm timing device
Lux - August 1942 - 2292576
Timer mechanism
Darnell - December 1951 - 2577004
Timer construction
Neumann - December 1953 - 2662595
Timer
Laviana - November 1959 - 2913048
Alarm timing device
Lux - August 1942 - 2292576
Timer mechanism
Darnell - December 1951 - 2577004
Timer construction
Neumann - December 1953 - 2662595
Timer
Laviana - November 1959 - 2913048
Application Number:
04/823291
Publication Date:
07/13/1971
Filing Date:
05/09/1969
View Patent Images:
Export Citation:
Assignee:
M. H. Rhodes Inc. (Hartford, CT)
Primary Class:
Other Classes:
968/811
International Classes:
G04F3/02; G04F3/00; G04F3/02
Field of Search:
58/21.13,16,21.15,21.155
Primary Examiner:
Wilkinson, Richard B.
Assistant Examiner:
Franklin, Lawrence R.
Claims:
The invention I claim is
1. In an interval timer having a spring motor, rotatable means for first winding the spring thereof to a condition for driving said timer during a predetermined full runout of said spring, output means, and a control mechanism responsive to said motor driving means for actuating said output means at one or more phases of said full runout; the improvement comprising:
2. The interval timer of claim 1; further comprising:
3. An interval timer as defined in claim 1, wherein said control mechanism includes a movable member, means for biasing said movable member to perform said output function, and a control element for controlling the movement of said movable member, whereby to perform said output function; said preventing means comprising:
4. The interval timer safety mechanism of claim 3; further comprising:
5. The interval timer safety mechanism of claim 3, wherein:
6. The interval timer safety mechanism of claim 5; wherein:
7. The interval timer safety mechanism of claim 6, wherein:
8. The interval timer safety mechanism of claim 7, wherein:
9. An interval timer comprising:
10. An interval timer as in claim 9 wherein:
11. An interval timer as in claim 9 wherein said output means comprises:
12. An interval timer as in claim 9 wherein said output means comprises:
1. In an interval timer having a spring motor, rotatable means for first winding the spring thereof to a condition for driving said timer during a predetermined full runout of said spring, output means, and a control mechanism responsive to said motor driving means for actuating said output means at one or more phases of said full runout; the improvement comprising:
2. The interval timer of claim 1; further comprising:
3. An interval timer as defined in claim 1, wherein said control mechanism includes a movable member, means for biasing said movable member to perform said output function, and a control element for controlling the movement of said movable member, whereby to perform said output function; said preventing means comprising:
4. The interval timer safety mechanism of claim 3; further comprising:
5. The interval timer safety mechanism of claim 3, wherein:
6. The interval timer safety mechanism of claim 5; wherein:
7. The interval timer safety mechanism of claim 6, wherein:
8. The interval timer safety mechanism of claim 7, wherein:
9. An interval timer comprising:
10. An interval timer as in claim 9 wherein:
11. An interval timer as in claim 9 wherein said output means comprises:
12. An interval timer as in claim 9 wherein said output means comprises:
Description:
FIELD OF THE INVENTION
This invention relates generally to an improved springwound interval timer, and is particularly concerned with an interval timer capable of operation after the passage of time intervals of irregular duration. The mechanism for this timer includes means which prevent the timer from operating during winding.
THE PRIOR ART
There are many types of interval timer mechanisms. Most interval timer mechanisms are adapted to give a single output, such as an audible sound or the closing of a pair of electrical contacts, at the expiration of a single predetermined time interval. Others have been devised to give a plurality of output indications during a timing cycle but at uniform subintervals.
THE INVENTION
The present invention provides an improved spring-wound timing device in which a control cam allows an output mechanism to operate one or more times during the course of a runout cycle, which times can be irregularly spaced apart, if desired, and the output mechanism remains inoperative unless the mainspring is first fully wound. As a result, first of all, the timer mechanism will not ring the bell during winding, and secondly, if it is wound fully, it will ring the bell accurately at the expected times during the runout cycle, even though these times are irregularly spaced; if not wound fully there will be no output indication whatsoever.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevational view of a spring-wound interval timer in accordance with the present invention;
FIG. 2 is a sectional view of the timer, taken along the lines 2-2 of FIG. 1;
FIG. 3 is a rear elevational view of the timer movement taken from the timer of the preceding figures with the movement in the completely unwound condition;
FIG. 4 is a side elevational view of the timer movement in a condition corresponding to that of FIG. 3;
FIG. 5 is a view similar to that of FIG. 3, but showing the timer movement in a partially wound condition;
FIG. 6 is a view similar to that of FIG. 4, but showing the timer in the condition of FIG. 5;
FIG. 7 is a view similar to that of FIG. 5 showing the timer movement almost fully wound;
FIG. 8 is a view similar to that of FIG. 7 showing the timer movement in its fully wound condition;
FIG. 9 is a view similar to that of FIG. 8 showing the timer movement during the runout or unwinding cycle;
FIG. 10 is a view similar to that of FIG. 9 showing the timer movement near the completion of the runout cycle;
FIG. 11 is a fragmentary sectional view taken along the lines 11-11 of the FIG. 10; and
FIG. 12 is a fragmentary view, similar to FIG. 10, showing an alternative embodiment in which the timer operates a pair of electrical contacts.
The same reference characters refer to the same elements throughout the several views of the drawing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a spring-wound timer 100 having a casing 102 and pedestal 104. At the front of the casing 102 is a dial 106 which indicates the time scale of the timer runout cycle, and this dial is traversed by an indicating pointer 110 upon a rotatable knob 108. The knob 108 also serves as a handle for manually winding the timer mainspring.
As best seen in FIG. 2, a bracket 112 floatingly mounts a bell gong 114 in the interior of the casing 102. A spring-wound timer movement 116 is in turn mounted within the interior of the gong 114 by a bracket 118. A main shaft 120 serves as the winding shaft as well as the output shaft of the spring-wound motor 116. In order to serve as the winding shaft, shaft 120 extends through an aperture in the center of the dial 106 and the winding knob 108 is secured thereto on the front side of the dial.
As best seen in FIGS. 3 and 4, the movement 116 comprises a pair of conventional movement plates, a rear plate 122 and a front plate 124, which are spaced apart by the usual spacer rods 126. In the space between the movement plates, the main shaft 120 has a spiral mainspring 128 wound thereabout. The mainspring is anchored at one end to the front plate 124 and at the other end to the winding shaft 120.
As the mainspring drives the shaft 120 during the runout cycle, the shaft turns a gearwheel 130 which is mounted on the shaft and frictionally clutched thereto. The gearwheel 130 in turn drives a pinion 132 secured to a shaft 134 which is journaled between the movement plates 122 and 124. The shaft 134 also has secured thereto a gearwheel 138 which drives a pinion 140 secured to another shaft 142 which is also journaled between the movement plates. The shaft 142 has secured thereto another gearwheel 144 which drives a pinion 146 secured to still another shaft 148 journaled between the movement plates. Finally, the shaft 148 has mounted thereon an escape wheel 150 formed with teeth 152 which cooperate with the pallets 154 of a verge member 156. The verge and pallets cooperate with the escape wheel teeth in the conventional way to time the runout of the timing movement 116.
A flexible wire spring 131 is anchored at one end to one of the spacers 126, and at the other end is bent to form a hook 133 which engages an opening 135 formed in the escape wheel 152, thus locking the movement 116 when the timer 100 is not in use. To unlock it, an operator 137 protruding through an elongated slit 143 formed in the dial 106 is manually pushed inwardly as shown by arrows 139 so that a shoulder 141 formed thereon dislodges the hook 133 to release the escape wheel 150. The unlocking operator 137 is biased back to its original position by a coil spring 147 engaging the shoulder 141 thereof, but it may be retained in position to unlock the timer movement by sliding it laterally in the dial slit 143 as shown by arrow 149 until a shoulder 145 engages the edges of the slit to restrain the operator 137.
As the timer movement 116 rotates its main shaft 120 at a timed rate during the mainspring runout cycle, it drives a control cam 160 which in turn activates an output mechanism 162 to strike the gong 114 at appropriate intervals to provide an audible timer output (or, as will be later described, an electrical output.) The control cam 160 is preferable formed of nylon, Delrin, or a similar material and is pressed onto a square driver nut 164 at the rear of the main shaft 120, behind the rear movement plate 122. As shown, the cam 160 performs one complete revolution as the knob 108 and shaft 120 are turned to wind the mainspring 128, and performs one full revolution during the runout cycle. The cam is formed with a plurality of rises 166 interspersed with notches 168 which control the output mechanism 162. Preferably the notches 168 are shaped so that the leading edges thereof are radial and the trailing edges are slanted away from the direction of rotation whereby to permit a cam follower to move abruptly into a notch 168 and be cammed or wedged out of the notch by the trailing edge.
The use of the cam 160 as the control element for the timer has a number of important advantages. Thus, for example, by using a cam, the multiplicity of outputs need not be uniformly spaced apart but can be irregularly spaced by virtue of the fact that the cam notches 168 can be irregularly spaced on the cam. Secondly, in production, timers having widely differing characteristics will all include substantially the same structural elements, the only difference being the shape of the cam. This will drastically reduce the cost of such devices by virtue of the reduction in the number of different parts required and in the number of different assembly steps required.
In the embodiment of FIGS. 1--11, the output mechanism comprises a lever 172 which is pivoted on the rear movement plate 122 by a pivot pin 174. Lever 172 has mounted thereon a cam follower here shown as an upstruck portion 180. The free end of lever 172 has secured thereto as on inturned free end 176 one end of a tension spring 178, the other end of which is anchored to one of the spacers 126. Spring 178 biases the lever 172 counterclockwise as viewed in FIGS. 3, 5, 7, 8 and 9, whereby to bias cam follower 180 toward engagement with the periphery of cam 160. Thus, with cam follower 180 riding on the periphery of cam 160, when a notch is encountered, i.e., registers with cam follower 180, the cam follower will drop abruptly into the notch to thereby permit lever 172 to pivot abruptly to the left or counterclockwise.
Disposed in the path of the free end of lever 172 is a striker element 170 which is pivoted on a spacer member 126 for movement from the position shown in FIG. 3 to the position shown in FIG. 9. Gravity normally biases the striker member 170 to the FIG. 3 position although a spring could be so employed. However, when lever 172 moves abruptly to the left under the influence of spring 178, it collides with striker 170 and knocks it clockwise or upward to strike bell 114 and thereby to ring the bell. Subsequent continued movement of the cam 160 will force cam follower out of the notch 168 to thereby restore lever 172 to its normal right-hand position and thereby permit the striker to drop down to its normal lowered position for the next operation.
To prevent operation of the output mechanism during the winding of the mainspring 128 and also to ensure that there will be no output unless the mainspring is substantially fully wound for a full-timed cycle, a blocking member 182 is provided which blocking member is rotatably mounted on the rear end of cam timer movement shaft 120 just is front of cam 160. The blocking member or element 182 has a portion which protrudes beyond the periphery of the cam 160 for engagement with the cam follower 180 to hold the cam follower away from the cam periphery and thereby prevent pivotal movement of lever 172 during rotation of the cam 160. Preferably, the portion of blocking member 182 that is engageable with cam follower 180 is provided with two protuberances 186 and 188 which flank an interposed depression 184 for receiving the cam follower 180 and holding it therein. As will be more fully described hereinafter, a reenabling driver element 196 is fixed to cam 160 and is engageable with blocking member 182 for moving the blocking member into and out of blocking relation with cam follower 180 upon the occurrence of certain events to be hereinafter described.
When the timer movement is completely unwound, as shown is FIGS. 3 and 4, the pointer 110 of the knob 108 points in the direction indicated by arrow 190, and the blocking element 182 is in its operative position in engagement with cam follower portion 180 to thereby hold the cam follower away from cam 160 and thus hold lever 172 in its rightmost position as viewed in FIG. 3. To start an operating cycle of the timer 100, the knob 108 is manually rotated to wind the mainspring 128, the control cam 160 thereby rotating with the mainshaft 120, the direction of rotation of the knob and control cam being shown by the arrows 192 and 194 respectively. During this winding operation, even though all the cam notches 168 are run past the cam follower tongue 180, the blocking element, which does not turn with the shaft 120 because it is freely rotatable thereon, remains in blocking engagement with the cam follower 180 to prevent lever 172 from ringing the bell during winding.
As the control cam 160 rotates in the mainspring-winding direction indicated by arrow 194, it carries with it a disabling and reenabling element 196 which is designed to drive the blocking element 182 into and out of its operative position relative to the tongue 180. Initially, however, the element 196 has no effect upon the blocking element 182.
FIGS. 5 and 6 show the timer mechanism partially wound. When the manual knob 108 has only been rotated as far as indicated by the arrow 190 in FIG. 5, the element 196 has not travelled far enough in the direction indicated by arrow 194 to engage the blocking element 182 and move it out of blocking relation with cam follower 180 to thus free lever 172. Subsequently, as seen in FIG. 7, when the manual winding knob 108 has been rotated a great deal further as shown by the position of the arrow 190, the element 196 is brought right up to the point of contact with the blocking element 182 but has not yet dislodged it from its blocking engagement with the cam follower tongue 180. In this view, the spring-wound timer movement 116 is almost but not quite fully wound, thus illustrating that even when the operator winds the mainspring almost all the way, if he inadvertently fails to wind it completely, the travel of the element 196 falls short of dislodging the blocking element 182, and as a result the blocking element continues to disable the output lever 172 and it will not be possible to strike a gong 114 during the following runout cycle.
On the other hand, if the manual knob 108 is turned somewhat further than the position of FIG. 7, the element 196 travelling with the control cam 160 in the direction indicated by arrows 194 will engage and dislodge the blocking element 182 as indicated by arrow 198. As this happens, the prominence 188 will ride under the cam follower tongue 180, stretching the biasing spring 178 somewhat until the tongue 180 is freed from its interlocking with the depression or low point 184.
FIG. 8 shows the position of the blocking element 182 after it has been dislodged from its engagement with the cam follower tongue 180 and is simply hanging loose on the main timer shaft 120. Once freed in this way of the blocking effect of the element 182, the output lever 172 is pivoted counterclockwise about its pivot 174 by the biasing spring 178, this motion carrying it at least far enough for the cam follower tongue 180 to engage the surface of the control cam 160 and be governed by the cam rises 166 and dwells 168 thereof.
At the moment depicted in FIG. 8 the timer movement 116 is fully wound, the blocking element 182 has been dislodged and disabled, the cam follower 180 and output lever 172 are under control of the cam 160, and the cam starts its timed return movement in the direction indicated by arrow 200 as the mainspring runout cycle begins.
In the view of FIG. 9 the runout cycle has been partially completed and the output lever 172 is seen pivoted counterclockwise as indicated by arrow 202 due to the fact that the cam follower tongue 180 thereof has now entered one of the cam notches 168 of the control cam 160. As this happens, the actuator lug 176 of the lever 172 impacts against the striker element 170 and drives it upwardly to strike the gong 114 as seen in FIG. 9, thus producing an audible ring of the bell. During the mainspring runout cycle this will occur once for each of the cam notches 168 formed on the profile of the control cam 160, the notches 168 each preferably having a radial leading edge to cause an abrupt leftward movement of lever 172 and a slanted trailing edge to wedge cam follower 180 out of the notch to rock lever 172 to the right.
In the view of FIG. 9 however, it is already apparent that as the runout cycle progresses and the knob 108 rotates to the position indicated by the arrow 190, the element 196 has once again engaged the blocking element 182 and is already in the process of returning it to its original operative position. In the view of FIG. 10 this process is well advanced as the timer movement 116 is seen entering the final stage of the runout cycle. As the manual knob 108 returns to the position indicated by the arrow 190, the continuing rotation of the control cam 160 in the direction indicated by arrow 200 causes the driver 196 to force the blocking element 182 angularly around to its operative position. Thus the cam follower tongue 180 is about to ride over the prominence 188 and reenter the retaining depression or low point 184 so that the output lever will again be engaged with the blocking element 182.
Thus the final event of each runout cycle is the repositioning of the blocking element 182 to disable the output lever 172 and thus make sure that the output lever will not function during the next winding and runout cycle of the timer unless the mainspring thereof is first fully wound. Full winding is the only way that the blocking element 182 can again be dislodged.
In FIG. 11 it is seen that the disabling and reenabling driver element 196 comprises a small metal roller 204 rotatably mounted upon a pin 206 which is received within an opening in the control cam 160. The latter is fixedly mounted upon the square nut 164 formed at the end of the main shaft 120 so that the cam rotates with the shaft, but the blocking element 182 is seen in the view of FIG. 11 to be loosely rotatable upon a cylindrical shoulder 208 which is integral with the nut 164 and surrounds the shaft 120.
In the alternative embodiment of FIG. 12 the operation is much the same as already described in that a cam 360 controls an output lever 372 by means of a cam follower tongue 380, and the lever is prevented from pivoting about a pin 374 on the movement plate 322 by a blocking element 382, except when the latter is dislodged by a driver element 396.
In this embodiment however the output is the closing of an electrical circuit comprising a first contact 500 which is fixed in place upon the movement plate 322, and a second contact 502 which moves with the output lever 372 to form a closed circuit with the first contact 500 when the blocking element 382 and the control cam 360 permit counterclockwise pivoting movement of the output lever 372. Obviously, if necessary, a quick-acting mechanism such as an overcentering toggle can be interposed between lever 372 and contact 502 to insure snap-action opening and closing of the contacts.
In either of its alternative forms, this invention provides an improved spring-wound timer mechanism in which the output function is governed by the control cam that will predetermine the sequence of operation. Accordingly, one mechanism can be produced for all sequences, the only part to be changed being the cam. Further, the output function is disabled by a blocking element during winding and also during runout unless the operator takes the precaution of fully winding the mainspring. If the user does not do this, the blocking element will not be dislodged from its operative position and the subsequent runout cycle will not produce any audible or other output. Thus, although the timing of a short runout cycle could be misleading, no damage will be done because no one will hear the bell or other output. If the mainspring is fully wound, the output function will be performed under control of the cam, but at the end of the runout cycle the blocking element will again be replaced in its operative position in case the next winding of the mainspring is not complete.
Since the foregoing description and drawings are merely illustrative, the scope of protection of the invention has been more broadly stated in the following claims; and these should be liberally interpreted so as to obtain the benefit of all equivalents to which the invention is fairly entitled.
This invention relates generally to an improved springwound interval timer, and is particularly concerned with an interval timer capable of operation after the passage of time intervals of irregular duration. The mechanism for this timer includes means which prevent the timer from operating during winding.
THE PRIOR ART
There are many types of interval timer mechanisms. Most interval timer mechanisms are adapted to give a single output, such as an audible sound or the closing of a pair of electrical contacts, at the expiration of a single predetermined time interval. Others have been devised to give a plurality of output indications during a timing cycle but at uniform subintervals.
THE INVENTION
The present invention provides an improved spring-wound timing device in which a control cam allows an output mechanism to operate one or more times during the course of a runout cycle, which times can be irregularly spaced apart, if desired, and the output mechanism remains inoperative unless the mainspring is first fully wound. As a result, first of all, the timer mechanism will not ring the bell during winding, and secondly, if it is wound fully, it will ring the bell accurately at the expected times during the runout cycle, even though these times are irregularly spaced; if not wound fully there will be no output indication whatsoever.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevational view of a spring-wound interval timer in accordance with the present invention;
FIG. 2 is a sectional view of the timer, taken along the lines 2-2 of FIG. 1;
FIG. 3 is a rear elevational view of the timer movement taken from the timer of the preceding figures with the movement in the completely unwound condition;
FIG. 4 is a side elevational view of the timer movement in a condition corresponding to that of FIG. 3;
FIG. 5 is a view similar to that of FIG. 3, but showing the timer movement in a partially wound condition;
FIG. 6 is a view similar to that of FIG. 4, but showing the timer in the condition of FIG. 5;
FIG. 7 is a view similar to that of FIG. 5 showing the timer movement almost fully wound;
FIG. 8 is a view similar to that of FIG. 7 showing the timer movement in its fully wound condition;
FIG. 9 is a view similar to that of FIG. 8 showing the timer movement during the runout or unwinding cycle;
FIG. 10 is a view similar to that of FIG. 9 showing the timer movement near the completion of the runout cycle;
FIG. 11 is a fragmentary sectional view taken along the lines 11-11 of the FIG. 10; and
FIG. 12 is a fragmentary view, similar to FIG. 10, showing an alternative embodiment in which the timer operates a pair of electrical contacts.
The same reference characters refer to the same elements throughout the several views of the drawing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a spring-wound timer 100 having a casing 102 and pedestal 104. At the front of the casing 102 is a dial 106 which indicates the time scale of the timer runout cycle, and this dial is traversed by an indicating pointer 110 upon a rotatable knob 108. The knob 108 also serves as a handle for manually winding the timer mainspring.
As best seen in FIG. 2, a bracket 112 floatingly mounts a bell gong 114 in the interior of the casing 102. A spring-wound timer movement 116 is in turn mounted within the interior of the gong 114 by a bracket 118. A main shaft 120 serves as the winding shaft as well as the output shaft of the spring-wound motor 116. In order to serve as the winding shaft, shaft 120 extends through an aperture in the center of the dial 106 and the winding knob 108 is secured thereto on the front side of the dial.
As best seen in FIGS. 3 and 4, the movement 116 comprises a pair of conventional movement plates, a rear plate 122 and a front plate 124, which are spaced apart by the usual spacer rods 126. In the space between the movement plates, the main shaft 120 has a spiral mainspring 128 wound thereabout. The mainspring is anchored at one end to the front plate 124 and at the other end to the winding shaft 120.
As the mainspring drives the shaft 120 during the runout cycle, the shaft turns a gearwheel 130 which is mounted on the shaft and frictionally clutched thereto. The gearwheel 130 in turn drives a pinion 132 secured to a shaft 134 which is journaled between the movement plates 122 and 124. The shaft 134 also has secured thereto a gearwheel 138 which drives a pinion 140 secured to another shaft 142 which is also journaled between the movement plates. The shaft 142 has secured thereto another gearwheel 144 which drives a pinion 146 secured to still another shaft 148 journaled between the movement plates. Finally, the shaft 148 has mounted thereon an escape wheel 150 formed with teeth 152 which cooperate with the pallets 154 of a verge member 156. The verge and pallets cooperate with the escape wheel teeth in the conventional way to time the runout of the timing movement 116.
A flexible wire spring 131 is anchored at one end to one of the spacers 126, and at the other end is bent to form a hook 133 which engages an opening 135 formed in the escape wheel 152, thus locking the movement 116 when the timer 100 is not in use. To unlock it, an operator 137 protruding through an elongated slit 143 formed in the dial 106 is manually pushed inwardly as shown by arrows 139 so that a shoulder 141 formed thereon dislodges the hook 133 to release the escape wheel 150. The unlocking operator 137 is biased back to its original position by a coil spring 147 engaging the shoulder 141 thereof, but it may be retained in position to unlock the timer movement by sliding it laterally in the dial slit 143 as shown by arrow 149 until a shoulder 145 engages the edges of the slit to restrain the operator 137.
As the timer movement 116 rotates its main shaft 120 at a timed rate during the mainspring runout cycle, it drives a control cam 160 which in turn activates an output mechanism 162 to strike the gong 114 at appropriate intervals to provide an audible timer output (or, as will be later described, an electrical output.) The control cam 160 is preferable formed of nylon, Delrin, or a similar material and is pressed onto a square driver nut 164 at the rear of the main shaft 120, behind the rear movement plate 122. As shown, the cam 160 performs one complete revolution as the knob 108 and shaft 120 are turned to wind the mainspring 128, and performs one full revolution during the runout cycle. The cam is formed with a plurality of rises 166 interspersed with notches 168 which control the output mechanism 162. Preferably the notches 168 are shaped so that the leading edges thereof are radial and the trailing edges are slanted away from the direction of rotation whereby to permit a cam follower to move abruptly into a notch 168 and be cammed or wedged out of the notch by the trailing edge.
The use of the cam 160 as the control element for the timer has a number of important advantages. Thus, for example, by using a cam, the multiplicity of outputs need not be uniformly spaced apart but can be irregularly spaced by virtue of the fact that the cam notches 168 can be irregularly spaced on the cam. Secondly, in production, timers having widely differing characteristics will all include substantially the same structural elements, the only difference being the shape of the cam. This will drastically reduce the cost of such devices by virtue of the reduction in the number of different parts required and in the number of different assembly steps required.
In the embodiment of FIGS. 1--11, the output mechanism comprises a lever 172 which is pivoted on the rear movement plate 122 by a pivot pin 174. Lever 172 has mounted thereon a cam follower here shown as an upstruck portion 180. The free end of lever 172 has secured thereto as on inturned free end 176 one end of a tension spring 178, the other end of which is anchored to one of the spacers 126. Spring 178 biases the lever 172 counterclockwise as viewed in FIGS. 3, 5, 7, 8 and 9, whereby to bias cam follower 180 toward engagement with the periphery of cam 160. Thus, with cam follower 180 riding on the periphery of cam 160, when a notch is encountered, i.e., registers with cam follower 180, the cam follower will drop abruptly into the notch to thereby permit lever 172 to pivot abruptly to the left or counterclockwise.
Disposed in the path of the free end of lever 172 is a striker element 170 which is pivoted on a spacer member 126 for movement from the position shown in FIG. 3 to the position shown in FIG. 9. Gravity normally biases the striker member 170 to the FIG. 3 position although a spring could be so employed. However, when lever 172 moves abruptly to the left under the influence of spring 178, it collides with striker 170 and knocks it clockwise or upward to strike bell 114 and thereby to ring the bell. Subsequent continued movement of the cam 160 will force cam follower out of the notch 168 to thereby restore lever 172 to its normal right-hand position and thereby permit the striker to drop down to its normal lowered position for the next operation.
To prevent operation of the output mechanism during the winding of the mainspring 128 and also to ensure that there will be no output unless the mainspring is substantially fully wound for a full-timed cycle, a blocking member 182 is provided which blocking member is rotatably mounted on the rear end of cam timer movement shaft 120 just is front of cam 160. The blocking member or element 182 has a portion which protrudes beyond the periphery of the cam 160 for engagement with the cam follower 180 to hold the cam follower away from the cam periphery and thereby prevent pivotal movement of lever 172 during rotation of the cam 160. Preferably, the portion of blocking member 182 that is engageable with cam follower 180 is provided with two protuberances 186 and 188 which flank an interposed depression 184 for receiving the cam follower 180 and holding it therein. As will be more fully described hereinafter, a reenabling driver element 196 is fixed to cam 160 and is engageable with blocking member 182 for moving the blocking member into and out of blocking relation with cam follower 180 upon the occurrence of certain events to be hereinafter described.
When the timer movement is completely unwound, as shown is FIGS. 3 and 4, the pointer 110 of the knob 108 points in the direction indicated by arrow 190, and the blocking element 182 is in its operative position in engagement with cam follower portion 180 to thereby hold the cam follower away from cam 160 and thus hold lever 172 in its rightmost position as viewed in FIG. 3. To start an operating cycle of the timer 100, the knob 108 is manually rotated to wind the mainspring 128, the control cam 160 thereby rotating with the mainshaft 120, the direction of rotation of the knob and control cam being shown by the arrows 192 and 194 respectively. During this winding operation, even though all the cam notches 168 are run past the cam follower tongue 180, the blocking element, which does not turn with the shaft 120 because it is freely rotatable thereon, remains in blocking engagement with the cam follower 180 to prevent lever 172 from ringing the bell during winding.
As the control cam 160 rotates in the mainspring-winding direction indicated by arrow 194, it carries with it a disabling and reenabling element 196 which is designed to drive the blocking element 182 into and out of its operative position relative to the tongue 180. Initially, however, the element 196 has no effect upon the blocking element 182.
FIGS. 5 and 6 show the timer mechanism partially wound. When the manual knob 108 has only been rotated as far as indicated by the arrow 190 in FIG. 5, the element 196 has not travelled far enough in the direction indicated by arrow 194 to engage the blocking element 182 and move it out of blocking relation with cam follower 180 to thus free lever 172. Subsequently, as seen in FIG. 7, when the manual winding knob 108 has been rotated a great deal further as shown by the position of the arrow 190, the element 196 is brought right up to the point of contact with the blocking element 182 but has not yet dislodged it from its blocking engagement with the cam follower tongue 180. In this view, the spring-wound timer movement 116 is almost but not quite fully wound, thus illustrating that even when the operator winds the mainspring almost all the way, if he inadvertently fails to wind it completely, the travel of the element 196 falls short of dislodging the blocking element 182, and as a result the blocking element continues to disable the output lever 172 and it will not be possible to strike a gong 114 during the following runout cycle.
On the other hand, if the manual knob 108 is turned somewhat further than the position of FIG. 7, the element 196 travelling with the control cam 160 in the direction indicated by arrows 194 will engage and dislodge the blocking element 182 as indicated by arrow 198. As this happens, the prominence 188 will ride under the cam follower tongue 180, stretching the biasing spring 178 somewhat until the tongue 180 is freed from its interlocking with the depression or low point 184.
FIG. 8 shows the position of the blocking element 182 after it has been dislodged from its engagement with the cam follower tongue 180 and is simply hanging loose on the main timer shaft 120. Once freed in this way of the blocking effect of the element 182, the output lever 172 is pivoted counterclockwise about its pivot 174 by the biasing spring 178, this motion carrying it at least far enough for the cam follower tongue 180 to engage the surface of the control cam 160 and be governed by the cam rises 166 and dwells 168 thereof.
At the moment depicted in FIG. 8 the timer movement 116 is fully wound, the blocking element 182 has been dislodged and disabled, the cam follower 180 and output lever 172 are under control of the cam 160, and the cam starts its timed return movement in the direction indicated by arrow 200 as the mainspring runout cycle begins.
In the view of FIG. 9 the runout cycle has been partially completed and the output lever 172 is seen pivoted counterclockwise as indicated by arrow 202 due to the fact that the cam follower tongue 180 thereof has now entered one of the cam notches 168 of the control cam 160. As this happens, the actuator lug 176 of the lever 172 impacts against the striker element 170 and drives it upwardly to strike the gong 114 as seen in FIG. 9, thus producing an audible ring of the bell. During the mainspring runout cycle this will occur once for each of the cam notches 168 formed on the profile of the control cam 160, the notches 168 each preferably having a radial leading edge to cause an abrupt leftward movement of lever 172 and a slanted trailing edge to wedge cam follower 180 out of the notch to rock lever 172 to the right.
In the view of FIG. 9 however, it is already apparent that as the runout cycle progresses and the knob 108 rotates to the position indicated by the arrow 190, the element 196 has once again engaged the blocking element 182 and is already in the process of returning it to its original operative position. In the view of FIG. 10 this process is well advanced as the timer movement 116 is seen entering the final stage of the runout cycle. As the manual knob 108 returns to the position indicated by the arrow 190, the continuing rotation of the control cam 160 in the direction indicated by arrow 200 causes the driver 196 to force the blocking element 182 angularly around to its operative position. Thus the cam follower tongue 180 is about to ride over the prominence 188 and reenter the retaining depression or low point 184 so that the output lever will again be engaged with the blocking element 182.
Thus the final event of each runout cycle is the repositioning of the blocking element 182 to disable the output lever 172 and thus make sure that the output lever will not function during the next winding and runout cycle of the timer unless the mainspring thereof is first fully wound. Full winding is the only way that the blocking element 182 can again be dislodged.
In FIG. 11 it is seen that the disabling and reenabling driver element 196 comprises a small metal roller 204 rotatably mounted upon a pin 206 which is received within an opening in the control cam 160. The latter is fixedly mounted upon the square nut 164 formed at the end of the main shaft 120 so that the cam rotates with the shaft, but the blocking element 182 is seen in the view of FIG. 11 to be loosely rotatable upon a cylindrical shoulder 208 which is integral with the nut 164 and surrounds the shaft 120.
In the alternative embodiment of FIG. 12 the operation is much the same as already described in that a cam 360 controls an output lever 372 by means of a cam follower tongue 380, and the lever is prevented from pivoting about a pin 374 on the movement plate 322 by a blocking element 382, except when the latter is dislodged by a driver element 396.
In this embodiment however the output is the closing of an electrical circuit comprising a first contact 500 which is fixed in place upon the movement plate 322, and a second contact 502 which moves with the output lever 372 to form a closed circuit with the first contact 500 when the blocking element 382 and the control cam 360 permit counterclockwise pivoting movement of the output lever 372. Obviously, if necessary, a quick-acting mechanism such as an overcentering toggle can be interposed between lever 372 and contact 502 to insure snap-action opening and closing of the contacts.
In either of its alternative forms, this invention provides an improved spring-wound timer mechanism in which the output function is governed by the control cam that will predetermine the sequence of operation. Accordingly, one mechanism can be produced for all sequences, the only part to be changed being the cam. Further, the output function is disabled by a blocking element during winding and also during runout unless the operator takes the precaution of fully winding the mainspring. If the user does not do this, the blocking element will not be dislodged from its operative position and the subsequent runout cycle will not produce any audible or other output. Thus, although the timing of a short runout cycle could be misleading, no damage will be done because no one will hear the bell or other output. If the mainspring is fully wound, the output function will be performed under control of the cam, but at the end of the runout cycle the blocking element will again be replaced in its operative position in case the next winding of the mainspring is not complete.
Since the foregoing description and drawings are merely illustrative, the scope of protection of the invention has been more broadly stated in the following claims; and these should be liberally interpreted so as to obtain the benefit of all equivalents to which the invention is fairly entitled.