What is claimed is
1. A pressing apparatus for the attachment of connector plates to a truss member comprising a frame for supporting a truss member with pairs of connector plates in aligned position on the upper and lower sides of the truss member, a roller press having a pair of transversely extending, vertically spaced upper and lower rollers, said press supporting said upper roller for direct engagement with the connector plates on the upper side of said truss member, means on said frame supporting a plurality of individual transversely extending reaction pads movable between a normal lowered position in underlying relation to the adjacent plates on the lower side of said truss member to a raised position in pressing engagement with said adjacent plates, said press supporting said lower roller for engagement with said pads to effect movement thereof from said lowered position into said raised position simultaneously with the engagement of the upper roller with the upper plates, and means for moving said press longitudinally relative to said frame to effect the joining of said connector plates with said truss in one pass of said press.
2. In a press for the assembly of connector plates with a truss in which pairs of said plates are positioned at opposite sides of the truss joints, comprising a frame for supporting a truss with said plate pairs positioned at desired locations at opposite sides of the truss joints, a roller press having a vertically spaced, transversely extending, upper and lower roller means, said upper roller means positioned on said press above a truss on said frame and said lower roller means being positioned on said press below such truss, means mounting said press for longitudinal movement with respect to said frame, said press supporting said upper roller means for direct engagement with the upper ones of said plates for forcing the teeth thereof into said truss, with longitudinal movement thereof, a series of transversely extending reaction pads supported on said frame between said lower roller means and the truss and serially engageable by said lower roller means with said longitudinal movement thereof for displacement from a lowered position to a raised position into engagement with the overlying lower plates for imbedding the lower plates into said truss at said joint simultaneously with the imbedding of the opposite truss plates so that the entire pressing force is carried by said roller press, and said plates are fully imbedded into the truss with a single pass of said roller press.
3. The press of claim 2 in which said reaction pads comprise a series of transversely elongated bars supported on said frame, and means guiding said bars for vertical movement between said lowered and raised positions.
4. The press of claim 3 further comprising a series of longitudinally spaced fixed supports on said frame defining groups of said bars therebetween having upper surfaces for supporting a truss member thereon in elevated relation to said bars and restraining said bars against longitudinal movement.
5. The press of claim 2 in which said roller press includes a carriage having a pair of vertical end frames rotatably supporting said rollers, track means extending longitudinally of said table, said carriage having wheels engaging said track means for movement thereon, and drive means on said carriage connected to drive said wheels to move said carriage along said track, said drive means also being connected to drive said rollers so that said carriage is self-feeding during the time that the rollers are in engagement with a truss on said frame.
6. The press of claim 5 in which said track means further comprises a pair of inverted V-shaped tracks, and said wheels are formed with a generally complimentary V-shaped groove received on said track.
7. The press of claim 5 in which said table is supported at its ends on fixed legs, a series of intermediate pivotally supported depending legs on said frame engaging the floor and means on said press engageable with said legs to pivot the same providing for the passage of said press thereby.
8. A press for the attachment of connector plates to a truss member, comprising a frame for supporting the truss member with pairs of the connector plates aligned at opposite sides of the truss member, a series of individual reaction pads on said frame positioned adjacent at one side of said truss member and movable into engagement with incremental portions of an adjacent connector plate, roller press means having one roller engageable serially with said pads to move said pads into pressing engagement with said plates and having a second roller in opposed relation to said first roller for engagement with the opposite side of the truss member, and means for moving said roller press means in a direction transverse to the pads to effect said serial movement of said pads to press the connector plates into the truss member.
9. The method of applying pairs of connector plates into opposite sides of a truss joint comprising the steps of passing a roller over one plate of said pairs forcing the same into the truss and simultaneously with the movement of said roller sequentially bringing a series of bars into pressing engagement with the opposite plate by moving said bars with a second and opposite roller, so that the distribution of pressing forces between said rollers is substantially confined at any one time to the width of one of said bars.
BACKGROUND OF THE INVENTION
Connector plates which have integral teeth formed therein have been known for many years for connecting the joints in pre-jigged wood structural components such as roof trusses, floor trusses, and other truss-like members such as wall panels, modular home components and the like. Typical examples of such plates are shown in U.S. Pat. Nos. 649,761; 1,806,522; 2,827,676; and 3,094,748.
It has been known to apply metal connector plates to truss members employing a roller, and in one instance, the truss is set up on a table and the roller applies the connector plates to one side. Then, the truss is turned over so that the plates can be applied to the back side. After the plates have been applied to both sides it is then common practice to pass the truss through a roller press again for final pressing.
In another known prior system, a single roller is used to partially imbed connector plates into the opposite sides of the joints of a pre-jigged truss. A partially finished structure is then ejected from the jig and carried by a conveyor to a second roller press for final pressing. These prior systems require considerable floor space and entail considerable handling of the truss member. This can be a distinct disadvantage since floor and roof trusses are formed in substantial lengths, up to 100 feet or more long in the case of roof trusses, and the requirements for extra handling and/or extra floor space for additional pressing operations becomes prohibitive.
SUMMARY OF THE INVENTION
The present invention is directed to a roller press for joining connector plates to truss members or the like in which the opposite pairs of plates are fully imbedded or attached in one pass of the roller press, thus eliminating the need for additional presses or additional handling of the truss member.
The principle of the invention is based on the use of a series of reaction pads which are movable by one of the press rollers, in incremental fashion, into pressing engagement with one of the connector plates, while the opposite roller is in direct engagement with the truss and the opposite connector plate. Since the reaction pads can be designed to press only a narrow increment at a time, the desired pressing force can be achieved so that the opposite connector plates can be fully imbedded in a single pass. The reaction pads concept, as applied in the present invention, permits the uses of conventional rollers in a press to join opposite pairs of connector plates, even though the rollers may extend 15 feet or more across the machine. A further advantage is that all of the pressing force is confined between the rollers; none of it is transmitted to the truss-supporting frame. This again is of advantage since the truss frame itself may exceed 15 feet in width and up to 100 feet or more in length. It thus can be designed to support merely its own weight and that of the applied pre-jigged truss member, which can be substantial.
The press of the present invention itself has important advantages over prior systems known to applicants, as identified above. The press requires less space, is flexible in its uses, permits fast setup and removal of the finished truss members, and thus contributes to faster production, and eliminates intermediate handling of the truss prior to its being fully joined by the truss plates.
It is accordingly an important object of the invention to provide apparatus and method for applying the connector plates to a truss member in one pass of a roller press.
A further object of the invention is the provision of pressing apparatus and method which employ a series of reaction pads or bars which are sequentially brought into pressing engagement with one, or a series of, opposite connector plates so that the distribution of pressing forces is limited at any one time substantially to the width of one of the bars.
Another object of the invention is the provision of a truss plate attaching machine which is simple in operation, which is easy to maintain, and which is rugged and dependable for use in an environment of saw dust, wood chips or the like.
These and other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a truss plate press according to this invention, with some of the parts being broken away or removed for the purpose of clarity;
FIG. 2 is a side elevation of a fragment of the machine of FIG. 1 showing the roller press with some of the parts removed for clarity;
FIG. 3 is a partially broken away front elevation of the machine of FIG. 2;
FIG. 4 is a partially broken away plan view of the machine of FIG. 2;
FIG. 5 is a fragmentary side elevation, partially broken away, showing the manner in which the rollers engage the truss member and the reaction bars;
FIG. 6A is a partial transverse view showing a bar in a lowered position and the manner in which it is supported on the frame; and FIG. 6B shows a reaction bar in its raised position.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1 and 2, a truss plate connector according to this invention is illustrated as including a frame 10 and a roller press 12. The frame 10 is formed with a plurality of longitudinally-extending table supports in the form of I-beams 14, 15, and 16, which are supported at their ends on permanent supports 18 in elevated relation to the floor 19. The machine which is illustrated for the purpose of this invention is a large one capable of forming and connecting roof trusses, such as shown by the truss 20 supported on the frame 10 in FIG. 1, and for this purpose, it is preferred to use three transversely spaced I-beams to provide structural support. However, in smaller machines, only the side I-beams 14 and 15 need be used for table support. The several joints of the truss 20 are to be connected by pairs of upper and lower connector plates 21 of the type described in the patents referred to in which protrusions are formed in one side thereof, which imbed into the wood to make a truss joint.
The frame 10 also includes a plurality of transversely extending and longitudinally spaced stationary bars 22. These bars which may be of metal or wood, are supported on and attached directly to the upper surfaces of the I-beams. Intermediate the stationary bars 22 there are received a plurality of individual transversely extending reaction pads 25. The structure of these pads, and the manner in which they are supported on the frame, may best be seen by reference to FIGS. 5 and 6. When a center I-beam is used, the pads 25 are split into transversely aligned pairs on either side of the center I-beam, as shown by the lowered pad 25A of FIG. 6A and the raised pad 25B of FIG. 6B. The pads 25 which may be formed of hardwood, plastic, metal, or the like, are formed with upper outwardly extending ledges 26 and 27 at the opposite ends for engagement with the upper surface of the I-beam. The ledges form an offset 32 so that, in the retracted position, the upper surfaces of the pads 25 normally rest below the upper surfaces 30 of the stationary bars 22, as illustrated by the pad 25A. The pad offsets 32 formed at the opposite ends of each pad 25, in combination with the sides of the I-beams, provide means for guiding the movement of the pads from the lowered position to the raised position. The depth of the offset 32 exceeds the amount by which the pads 25 are lifted or raised by the roller press and also exceeds the length of the truss plate projections, so that the pads are at all times restrained by the I-beams against transverse movement. The spaced stationary bars 22, which include a plurality of the pads 25 therebetween, support the truss 20 in somewhat elevated relation to the pads 25 and restrain the pads against longitudinal movement.
The upper surfaces 30 of the station bars 22 also provide the means by which the truss 20 may be pre-jigged onto the top of the frame 10, and for this purpose, a jigging fixture which includes adjustable angle braces 35 may be conveniently applied directly to the surfaces 30.
In the preferred embodiment of the invention the pads 25 simply rest by gravity on the I-beams 14, 15, and 16. If one of them becomes damaged it may be simply removed by a lifting bar and replaced.
The roller press 12 is formed with a lower carriage 40, and a pair of upright end frames 42 and 43 positioned on either side of the table 10. The carriage 40 is formed with side frame members 44 and cross frame members 45 to form a box-like carriage structure for supporting the drive motors and end frames. The carriage 40 is mounted for movement longitudinally of the frame 10 on floor-tracks 46 which are laid on the floor just outside of the fixed supports 18. The tracks are formed with an inverted V-shaped section 47, as shown in FIG. 3, and the carriage is provided with track engaging wheels 48 which are formed using generally complimentary V-shaped grooves. The track is thus self-cleaning of sawdust and wood shavings. The carriage 40 runs on the tracks 46 in a longitudinal direction from one end of the frame to the other.
The roller press 12 supports the pair of transversely extending, vertically spaced upper and lower rollers, including a first roller 50 between the end frames positioned in generally underlying relation to the frame 10 and an upper roller 52 which is adjustably carried between the end frames 42 and 43 in overlying relation to the frame 10. When the frame 10 is provided with a central I-beam 15, as shown, the lower roller 50 is divided into two transversely aligned sections 50A and 50B as shown in FIGS. 3 and 4. Each of these sections respectively are received between the longitudinal I-beams.
The upper roller 52 is adjusted for direct engagement with the connector plates 21 on the upper surface of the truss member 20 and effectively presses the truss plates into the wood, as shown in FIG. 5.
The lower roller 50, on the other hand, is supported by the end frames 42 and 43 for direct lifting engagement with the reaction pads 25, as shown also in FIG. 5. The reaction pads 25 are thus serially engageable by the lower roller 52 with longitudinal movement thereof and are linearly displaced from their lowered position (FIG. 6A) to the raised position (FIG. 6B) and into engagement with the overlying bottom truss plates 21 for imbedding the plates into the truss at its joints simultaneously with the imbedding of the opposite truss plates. The pads 25 are then returned to their lowered position with the passing of the roller 50. The (pressing) force thus applied through the reaction pads 25 primarily in increments defined by the width of one of the pads, and in this manner the distribution of pressing force between the rollers is confining at any one time to a region corresponding substantially to a width of one of the pads 25.
In a typical example, the rollers may be formed of a hollow steel skin of three-fourths inch thickness which is internally strengthened or supported by transversely spaced disks at about 3 feet spacing mounted on a 1 1/2 inch steel shaft, and may be, for example, 18 inches in diameter. The pads 25 may vary in width and depth and a typical example includes pads formed of one inch square steel bar structure, with the cutout portion 32 having a depth of five-sixteenths inch. This provides for imbedding plates having five-sixteenths inch prongs or teeth, and it is within the scope of the invention to provide rollers of differing diameters and pads of differing widths and retraction distances as required for imbedding the various kinds of connector plates which are available on the market.
It is within the scope of the invention to hold the press 12 in a fixed position and to move the table or frame longitudinally with respect to the press. However, this has the disadvantage of requiring additional floor space.
When the frame 10 is formed with substantial length, as shown in FIG. 1, it is desirable to provide intermediate temporary supports to eliminate any sag in the I-beams 14, 15, and 16. To this end a series of pendulum type legs 60 may be mounted in depending relation from the side beams 14 and 16. The carriage 40 may be provided with upper saddle-shaped rails 62 on each side, and as the carriage approaches one pair of the legs the rails 62 are proportioned to engage underlying rollers 64 on the I-beams which provide temporary support for the frame onto the carriage, thus permitting the pendulum legs 60 to be swung out of position so that the carriage can pass. The carriage, when contacting the legs 60, simply moves them out to a horizontal position until the carriage has passed.
Means for driving the carriage in the longitudinal direction includes a pair of drive motors 70 and 72 and reduction gears 74, as shown in FIGS. 3 and 4. The drive motor 70 drives a pair of chain sprockets 75. One of the chain sprockets 75 is connected to drive the forward wheel 48 through a torque limiting clutch 76. At the same time, the other sprocket 75 is connected to drive the lower roller 50 through a large chain sprocket 77. In this manner the lower roller is driven in the same direction but at a somewhat lower peripheral speed than the wheel. On the other hand, the upper roller 52, which must be driven in the opposite direction, is driven by the motor 72 through its sprocket 80 and a corresponding large sprocket 82. When the rollers 50 and 52 engage a truss on the frame 10 they become self-feeding and move under the drive of the motors 70 and 72. It is convenient to leave the drive wheels 48 engaged through the torque limiting clutch 76 during the pressing operation. When there is no truss on the frame, the carriage will be driven at a somewhat greater speed by the wheels.
The operation of the invention is largely self-evident from the foregoing description. Suitable jigging may be arranged on the stationary bars 22 according to the desired production run, and the truss members laid in place. The lower connector plates 21 may be placed by hand onto the wood and they will remain there as the teeth of these plates are sharp and stick to the wood with little manual pressure. The upper connector plates may be similarly laid in position and they will tend to stay in position without sliding or moving.
The roller press, which has been moved to one or the other end of the frame 10 is started by starting the motors 70 and 72, and it proceeds forward by driving the front wheels 48 until the upper and lower rollers come into engagement with the truss. At this time the press becomes self-feeding. As a pair of connector plates is approached the top plate is pressed down by the top roller and the bottom plate is pressed by the previously described serial movement of the reaction pads 25. All of the pressing force is confined between the rollers and none is transmitted to the frame 10. The use of reaction pads 25 permits sufficient force to be applied so that both the top and bottom connector plates are fully and completely imbedded with one pass of the press.
The pendulum legs may be spaced on approximately 15 feet intervals, and the yoke or rail 62 may be adjusted to provide about a one-eighth inch lifting movement of the table to release the pendulum legs 60 from engagement with the floor so that they can be swung out of position while the press is passing. Camber blocks may be fixed in the chord of the truss so that a finished truss is formed using a predetermined camber.
It is understood that where a smaller version of the roller press is desired the center I-beam 15 may be eliminated and the reaction bars and the lower roller may be made in one piece.
While the method herein described, and the form of apparatus for carrying this method into effect, constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to this precise method and form of apparatus, and that changes may be made in either without departing from the scope of the invention.