Abstract:
A truss jigging system has an elongated table forming a support plane and formed with a plurality of parallel slots extending between the two long edges. The table has a plurality of the following: locating pins, carriages, endless belts, idler wheels, and, drive wheels. Each endless belt is strung around a respective one of the idler wheels and a respective one of the drive wheels to form a pair of elongated runs, one run being an elongated return run and the other run having a respective one of the carriages affixed thereto and coursing through a respective slot such that, driving the drive wheel moves the locating pin back and forth along the front to back axis of the respective slot.

Description:
CROSS-REFERENCE TO PROVISIONAL APPLICATION(S) 
     This application claims the benefit of U.S. Provisional Application No. 61/888,570, filed Oct. 9, 2013, the disclosure of which is fully incorporated herein by this reference thereto. 
    
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
     The invention relates to work holders and, more particularly, to a truss jigging system with provisions for reducing the length of time between changing from one jig formation to another. 
     Home architects are always striving for new and fresh designs to appeal to the new home buyer and/or home renovator who wants something distinctive. One of the ways to provide fresh new designs is to design elaborate truss-supported structures where nearly every truss has a unique design. Hence there is pressure from the marketplace for truss jigging systems which have a very short times between changing from one jig formation to another. 
     It is an object of the invention to provide a fully automatic truss jigging system, wherein the time to change jig formation is as short as a minute to just a few minutes. This object of the invention is achieved by controllable drive systems that are driven from a controller and spin a belt. Albeit, it is expected that user will give the controller and manual signal to make the change of the jig formation. 
     It is an alternate object of the invention to provide a semi-automatic truss jigging system. This is not a backward step from the previous object of the invention. Instead, this allows for, among other things, a user to make a last second personal intervention to make fine, last-minute adjustments. 
     It is a further object of the invention to a truss jigging system with manual drives for changing the jig formation (eg., like a hand crank or a wrench put to service as a hand crank). And again, this object is also not a backward step from the previous two. When architects and/or builders are designing and constructing a distinctive and elaborate structure, the unexpected might happen. There might be a need to make a last truss based on measurements made by the builder in the field. The manual drive provisions might make the changeover time a lot slower than the fully automatic and semi-automatic provisions. However, when workers feel like they aren&#39;t getting exactly what they need, and to the point where they mistrust the computers, the manual speed-drive provisions restore the jig template formation fully back to humans. 
     These and other aspects and objects are provided according to the invention in a truss jigging system comprising the following. 
     There is a table forming a support plane on which work pieces are supported and extending between a front edge and a spaced-away back edge and being elongated side to side between a left side edge and a spaced-away right side edge. 
     The table is formed with a plurality of elongated, narrow surface slots through the support plane and extending on generally parallel axes to each other in the front to back direction, the surface slots being recessed down in the table to widen out into enlarged, tubular slideways that are spaced below the support plane and correspondingly are elongated and extend generally parallel with the same axis as the respective surface slot. 
     There are a plurality of locating pins, and, a plurality of carriages for not only inserting into the slideways for sliding transit therein but also for carrying one of the plurality of locating pins for sliding transit therewith while the locating pin extends through the surface slot and protrudes above the support plane. 
     There is furthermore a plurality of endless belts, one each for each carriage, and, a plurality of idler wheels, one each for each slideway, and each disposed proximate the front edge of table to service a respective one of the slideways, as well as, a plurality of drive wheels, one each for each slideway, and each disposed proximate the back edge of table to service a respective one of the slideways. 
     Wherein, each endless belt is strung around a respective one of the idler wheels and a respective one of the drive wheels to form a pair of elongated runs, one run being an elongated return run and the other run having a respective one of the carriages affixed thereto and coursing through the respective slideway that the respective two wheels service, such that, driving the drive wheel moves the locating pin back and forth along the front to back axis of the respective surface slot. 
     It is optional that the table defines a plurality of inverted-T shaped slots wherein the vertical parts correspond to the surface slots and horizontal parts correspond to the slideways. 
     The table might further comprises a pair of parallel jigging bars for each inverted-T shaped slot. 
     The table might moreover further comprises a support deck below the level of and for supporting the jigging bars, the support deck extending between a front edge and a spaced-away back edge and being elongated side to side between a left side edge and a spaced-away right side edge. 
     Preferably, the jigging bars have top surfaces level with the support plane. and 
     The table might correspondingly comprises a multiplicity of infill sections which are elongated between a front edge and spaced back edge and compact between spaced front and right edges, and sized for filling in between each of the plurality of pairs of jigging bars that define a respective one of the plurality of invert-T shaped slots and are supported by the support deck for presenting a work surface level with the tops of the jigging bars and level with the support plane. It is preferred then that, at least one adjacent pair of a jigging bar and infill section define a tubular conduit parallel to the horizontal part of the inverted-T shaped slot and providing a passageway for the return run of the endless belt. 
     It is a preferred aspect of the invention to further provide the following:— 
     a second plurality of plurality of locating pins; 
     a second plurality of carriages for not only inserting into the slideways for sliding transit therein but also for carrying one of the second plurality of locating pins for sliding transit therewith while the locating pin extends through the surface slot and protrudes above the support plane; 
     a second plurality of endless belts, one each for each of the second plurality of carriages; 
     a second plurality of idler wheels, one each for each slideway, and each disposed proximate the front edge of table to service a respective one of the slideways; 
     a second plurality of drive wheels, one each for each slideway, and each disposed proximate the back edge of table to service a respective one of the slideways; 
     wherein each of the second plurality of endless belts is strung around a respective one of the second plurality of idler wheels and a respective one of the second plurality of drive wheels to form a pair of elongated runs, one run being an elongated return run and the other run having a respective one of the second plurality of carriages affixed thereto and coursing through the respective slideway that the respective two wheels service such that, driving the drive wheel moves the locating pin back and forth along the front to back axis of the respective surface slot; and 
     wherein each slideway services two carriages, one of the first plurality and one of the second plurality, which cannot pass each other but can be driven independently. 
     The table might further defines a pair of tubular conduits flanking each slideway, one providing a passageway for the return run of the respective one of the first plurality of endless belts and the other providing a passageway for the return run of the respective one of the second plurality of endless belts. 
     It is preferred to provide a plurality of drive motors, one each for driving a respective one of the plurality of drive wheels, as well as, a control system for controlling the plurality of drive motors. 
     It is furthermore preferred if the idler wheels are mounted to the table flush below the support plane so that, other than the locating pins and work pieces, the airspace above support plane proximate the front edge of the table is otherwise clear. 
     The plurality of drive motors may be mounted to the table along the back edge such that the project above the support plane. 
     For maintenance and adjustment purposes, it is preferred to provide a plurality of belt tensioning systems, one each for a respective one of each of the plurality of belt. Each belt tensioning system might be implemented in the form of comprising a horizontally-adjustable mounting provision that is adjustable back and forth in the front to back direction and provides a mounting provision for one of the drive or idler wheels. 
     The endless belt can be reckoned as ‘endless’ in several different ways. One way includes the following. That is, each endless belt includes the respective carriage affixed thereto whereby the carriage forms a splice between opposed tag ends of the belt. 
     This application is commonly-invented, commonly-owned with U.S. Pat. No. 5,048,409, entitled Truss Fabrication Machine with Joystick Controls, and U.S. Pat. No. 6,318,251, entitled Automatic Control System for a Truss Fabricating Machine, the disclosures of which are incorporated herein by this reference thereto. 
     A number of additional features and objects will be apparent in connection with the following discussion of the preferred embodiments and examples with reference to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       There are shown in the drawings certain exemplary embodiments of the invention as presently preferred. It should be understood that the invention is not limited to the embodiments disclosed as examples, and is capable of variation within the scope of the skills of a person having ordinary skill in the art to which the invention pertains. In the drawings, 
         FIG. 1A  is a perspective view of a truss jigging system in accordance with the invention, with portions broken away; 
         FIG. 1B  is a perspective view comparable to  FIG. 1A , except on an enlarged scale with further portions token away; 
         FIG. 2A  is a top plan view of  FIG. 1A ; 
         FIG. 2B  is a top plan view of  FIG. 1B ; 
         FIG. 3A  is an enlarged scale perspective view of detail IIIA in  FIG. 2A , comprising a first embodiment of a drive system in accordance with the invention; 
         FIG. 3B  is a perspective view comparable to  FIG. 3A , except of a second embodiment of a drive system in accordance with the invention, comprising not only a drive system but also a tensioning system; 
         FIG. 4A  is a top plan view of  FIG. 3A ; 
         FIG. 4B  is a top plan view of  FIG. 3B ; 
         FIG. 5  is a right side elevational view of  FIG. 3A ; 
         FIG. 6  is an end elevational view  FIG. 3A  of the inboard edge; 
         FIG. 7A  is an enlarged scale perspective view of detail VIIA in  FIG. 2A , comprising an idler system and tensioning system; 
         FIG. 7B  is an enlarged scale perspective view comparable to  FIG. 7B  except showing a flush mount idler system, comprising an idler system alone, and for lining up opposite the combined drive system and tensioning system of  FIGS. 3B and 4B ; 
         FIG. 8  is a top plan view of  FIG. 7A ; 
         FIG. 9  is a left side elevational view of  FIG. 7A ; 
         FIG. 10  is an end elevational view of  FIG. 7A  of the outboard edge; 
         FIG. 11  is an enlarged scale perspective view of detail of a single jigging bar in  FIG. 1A or 1B , with central portions broken away; 
         FIG. 12  is an enlarged scale end elevational view thereof; 
         FIG. 13  is an enlarged scale perspective view of a single puck carriage for the truss jigging system in accordance with the invention, wherein an above-table puck as typical of the eight shown in  FIG. 1A  is removed from view; 
         FIG. 14  is a top plan view of  FIG. 13 ; 
         FIG. 15  is an end elevational view of  FIG. 13 ; 
         FIG. 16  is a left side elevational view  FIG. 13 ; and 
         FIG. 17  is an idler-side elevational view of either the  FIG. 1A or 1B  combined idler system and tensioning system, except:—
         that not only the idler system and tensioning system but also a cover therefor have been removed from view to reveal how the carriage and locating pin occupy an inverted-T shaped slot defined by a pair of the T-shaped jigging bars as better shown by  FIGS. 11 and 12 ,   showing better how the counter-wound endless drive belts are rigged as well,   showing better how locating puck is mounted on the locating pin above the plane of the top surfaces of the T-shaped jigging bars, and   additionally showing a pair of infill plates fastened or affixed to the table surface flanking the pair of T-shaped jigging bars, and creating a work surface flush with the elevation of the plane of the top surfaces of the T-shaped jigging bars.       

     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIGS. 1A through 2B  show a truss jigging system  20  in accordance with the invention. It comprises a table deck  22 , parallel pairs of jigging bars  24  defining a single slot  26  therebetween and in each slot  26  a pair of pucks  28  are confined to traverse independently of each other, back and forth over the same the slot. 
     Each of the pair of pucks  28  carried by carriage gear (see, eg., reference numeral  74  in any of  FIGS. 13 through 17 ) the same slot  26  can traverse that slot  26  independently of each other, but the carriages  74  (and hence the pucks  28 ) cannot pass one another. Accordingly, the pucks  28  can define a spacing between each other. The pucks  28  comprise the work contacting elements of the truss jigging system  20 . 
     Each parallel pair of jigging bars  24  terminates proximate an idler-side edge of the table deck  22  at an combined idler and tensioning system  30  in  FIGS. 1A-2B, 7A and 8-10 . In contrast,  FIG. 7  shows an idler system  31  comprising just simply an idler system alone. The opposite ends of each parallel pair of jigging bars  24  terminate proximate a drive-side edge of the table deck  22  at a drive system  32  in  FIGS. 1A-3A, 4A and 5-6 . In contrast,  FIGS. 3B and 4B  an alternate embodiment of a drive system  33  comprising a combined drive system and tensioning system for lining up on the opposite ends of the T-shaped jigging bars  24  as the FIGURE flush mount idler system  31 , comprising an idler system alone. 
     Typically, a line of the pucks  28  for each slot  26  that are closest the drive system  32  or  33  and coursing on a diagonal slant would contact a rafter (or, top chord, and not shown). Correspondingly, the line of pucks  28  for each slot  26  closest to the idler system  30  or  31  would contact a tie beam (or, bottom chord, and not shown). Often, this line of pucks  28  for each slot  26  that are closest to the idler system  30  or  31  are also typically parallel with the idler-side edge of the table deck  22 . 
     Optionally the table deck  22  comprises plate steel stock about a half inch thick. The extent between the idler-side and drive-side edges is preferably in the range of twelve to sixteen feet (˜3½m and ˜5 m). The extent between a right (near side in  FIGS. 1  and  2 ) and left edge is preferably anywhere from eighty to one-hundred feet (˜24 m to ˜30 m). The table deck  22  is greatly abbreviated in  FIGS. 1A through 2B  in order to allow better illustration of the jigging bars  24 , idler systems  30  or  31 , and drive systems  32  or  33 . 
     Preferably the distance between centers of two adjacent slots  26  is about two feet (or about ˜0.6 m). Hence each neighboring set of parallel jigging bars  24  leaves a swath on the table deck  22  that is about seventeen inches (˜0.4 m) or so wide. These swaths are in-filled with infill sections  96  (see  FIG. 17 ). These infill sections  96  typically comprise particle board covered by plastic to create more or less a uniform surface for truss components to be arranged upon (not shown), and which corresponds to top elevation of the jigging bars  24 . 
     It can be appreciated now that, a hundred-foot wide truss jigging system  20  is going to forty-nine slots  26 , and, ninety-eight drive systems  32  or  33 . 
       FIG. 7B  shows better that the idler system  31  is mounted on table deck  22  (not shown in  FIG. 7B ) by flush mounting bolts. This provides a flush mount for this idler system  31 . This clears the airspace above the front edge of the truss jigging system  20  in order to allow both truss stock and a completed truss to be slid smoothly on and off over the idler system  31 . 
       FIGS. 3A through 6  show better several aspects of the drive system  32  or  33 . Drive system  32  comprises a pair of stepping motors  34 , each driving a respective right angle gear  36 , the output of which is one or the other of a pair of drive pulleys  38  for driving toothed belts (see, eg., reference numerals  92  and/or  94  in  FIG. 17 ). These toothed belts correspond to or are at least comparable to timing belts. The drive systems  32  and/or  33  are supported off the table deck  22  by means of a C-shaped frame  42  and mounting plate  44  joined by fasteners  46 . 
       FIGS. 7A , and,  8  through  10  show better several aspects of an idler and tensioning system  30 . It comprises a pair of idler pulleys  52  counterpart to the pair of drive pulleys  38  in  FIG. 3A  for providing for the return of a driven toothed belt (see, eg., reference numerals  92  and/or  94  in  FIG. 17 ) driven by each drive pulley  38  in FIG.  3 A. The idler pulleys  52  are mounted underneath respective slide plates  54  by shaft nuts  56 . The slide plates  54  are pulled in tension relative fixed tabs  58  by respective (short and long) threaded drive rods  62  and  64 . Each slide plate  54  has its own set of locking nuts  66  which, when slack, permit the slide plate  54  to pulled in tension relative the respective fixed tab  58 . Tightening the locking nuts  66  fixes the slide plate  54  to a stationary position relative mounting plate  68 , which is fixed in common with the tabs  58  by C-shaped frame  72 . 
       FIGS. 3B and 4B  shows that a corresponding belt tensioning provisions comprising respective (short and long) threaded drive rods  62  and  64  is incorporated in the combined drive and tensioning system  33  in  FIGS. 1B, 2B, 3B and 4B . 
       FIGS. 11 and 12  show better several aspects of the jigging bars  24 . They are T-shaped in cross-section and when juxtaposed in pairs as shown better still in  FIG. 17 , the jigging bars  24  define the slot  26  (not indicated in  FIG. 17 or 18 ), and the slot  26  takes on an inverted-T shape.  FIG. 11  shows that the jigging bars  24  are rather slender, preferably about twelve to sixteen feet long (˜3½ m and ˜5 m).  FIG. 12  shows that the jigging bars  24  are substantial in cross-section, comprising in accordance with one preferred and non-limiting embodiment a block two and half inches (˜6 cm) wide by one and half inch (˜4 cm) high, with a stem one and half inch wide (˜4 cm) by one inch tall (2.54 cm). 
       FIGS. 13 through 17  show better aspects of the puck carriage  74 .  FIG. 17  shows better still that the carriage  74  traverses in the slot  26  defined between parallel jigging bars  24 . 
     In  FIG. 13 , the carriage  74  comprises a main block  78  that carries a puck-mounting pin  76  (again, puck  28  is not shown, but see, eg.,  FIG. 17 ). 
     As  FIG. 15  shows better, the main block  78  defines one and another C-shaped, opposite channels  82  and  84  respectively. Channel  82  is open all the through the axial extent thereof through the main block  78 . Channel  84  optionally differs in that it is a clamping channel  84  and is partitioned by slide abutment  88 . 
       FIGS. 13-17  taken together show better aspects of the manner of driving the carriage  74 . Each slot  26  that is defined between jigging bars  24  is occupied by two carriages  74 , but only one is shown in  FIGS. 13-17 . This one carriage  74  is driven by an involved belt  94  which has two ends. This carriage  74  also allows a non-involved belt  92  to pass without obstruction for driving another carriage  74  in the same slot (see, eg.,  FIG. 2A or 2B ). 
     To refer back briefly to  FIG. 2A or 2B , each of the pair of pucks  28  carried by its respective carriage  74  in the same slot  26  can traverse that slot  26  independently of each other, but the carriages  74  cannot pass one another. Nevertheless, the pucks  28  can define a spacing between each other. 
     Resuming again in  FIGS. 13-17 , the belt ends are not shown but are respectively clamped on one side and the other of the slide abutment  88  of the main block  78  by belt clamps  86 . These belt clamps  86  have tooth formations to better clamp the belt  94  and by meshing into the teeth of the belt  94 . These belts  92  and  94  are considered to be essentially endless, wherein the carriage  74  merely forms a splice between the opposed tag ends thereof. 
     Again, the involved belt  94  begins and terminates in channel  84  on opposite sides of the slide abutment  88 , the beginning end and the terminating end thereof being clamped to the carriage  74  by belt clamps  86 . 
     From its beginning to its termination, the involved belt  94  occupies one-half of slot  26  (the other half occupied by the non-involved belt  92 ) and extends from carriage  74  towards drive system  32  or  33  to loop around one drive pulley  38 , then extends towards idler system  30  or  31  to loop around one idler pulley  52 , and then ultimately returns to its termination about where its beginning is, again at carriage  74 . 
     The T-shaped jigging bars  24  not only form an inverted-T shaped slot which serves as the major slideway for the carriages  74  and locating pins (eg., carrying locating pucks  28 ). The pair of T-shaped jigging bars  24  also form an outboard pair of tubular conduits for the return runs of the belts  92  and  94  to return through. That is, each belt  92  or  94  comprises an elongated return run and an elongated other run to which one carriage  74  is affixed. 
     Given the foregoing, the drive pulley  38  that drives this belt  94  and results in moving the carriage  74  in the slot  26 . In contrast, turning the other drive pulley  38  that drives belt  92  does not move this carriage  74  in  FIGS. 13-17 . Belt  92  is free to pass through the carriage  74  by virtue of the open channel  82 . Belt  92  is, however, readily available in service of independently driving the other carriage  74  (this other carriage is not shown in  FIGS. 13-17 ) that occupies this slot  26  with the carriage  74  that is indeed shown in  FIGS. 13-17 . 
     Briefly, in connection with the clamping channel  84 ,  FIG. 17  shows better that it is served by the sliding abutment  88  sliding against the stem of the adjacent jigging bar  24  in order to avoid sliding contact by either the belt  94  or its clamps  86 . 
       FIG. 17  is an idler-side elevational view of either the  FIG. 1A or 1B  combined idler system and tensioning system  30 , except that here in  FIG. 17 , not only the idler system and tensioning system but also a cover therefor have been removed from view. This is done to reveal how the carriage  74  and locating pin for pucks  28  occupy the inverted-T shaped slot  26  defined by a pair of the T-shaped jigging bars  24  as better shown by  FIGS. 11 and 12 . 
       FIG. 17  shows better how the counter-wound endless drive belts  92  and  94  are rigged as well. The locating puck  28  is mounted on the the respective locating pin above the plane of the top surfaces of the T-shaped jigging bars  24 . The nut tightening the locating puck  28  to the locating pin can be tightened such that the puck  28  and carriage  74  can clamp on the shoulders of the bars  24  that define the vertical part (eg, upper narrow part) of the inverted-T shaped slot  26 . In others the puck  28  can be used as an upper jaw of a clamping feature to clamp it tight in place. 
       FIG. 17  further shows a pair of infill plates  96  fastened or affixed to the table deck surface  22  flanking the pair of T-shaped jigging bars  24 , and creating a table work surface (or work-piece support surface) flush with the elevation of the plane of the top surfaces of the T-shaped jigging bars  24 . 
     Pause can be taken to provide the following remarks, some which might be redundant but are included for better illumination of certain aspects of the invention. 
     If it is preferred to keep the airspace above the idler-side side edge of the table flush with the work-piece support surface, then preferably the tensioning provisions are moved to the drive-side side edge of the table. 
     The drive motors are preferably step motors. They can be either vertically mounted or horizontally mounted with a right-angle gear box. The horizontal mounting does provide for lower airspace interference, but if work pieces and completed trusses are always only going to be put on and taken off the table from the idler-side side edge, then this is not a worry. 
     Direct clamping by tightening nuts on the pucks  28  is desirable when some of the wooden lumber has bows in it. The bow in the lumber can put sufficient lateral pressure on the pucks to move them out of alignment. The pucks can force the belts to drive the motors a little bit. This is especially observed with the vertical mount motors. 
     While not shown, an alternative drive source for the drive wheels  38  might be a hand crank. In fact, in economic versions of the truss jigging system  20  in accordance with the invention, it might be preferred to provide it in a hand-crank version only. It would further be preferred to provide a digital read-out for the location of the locating pucks  28  (or locating pins). 
       FIGS. 2A and 2B  show the general layout of the original concept of the truss jigging system in accordance with the invention.  FIGS. 3A, 4A and 6  show the right angle drive system  32  on a fixed base.  FIGS. 3B and 4B  show a vertical drive system  33  on an adjustable base.  FIGS. 7A and 8-10  show the adjustable idler base  30 .  FIG. 7B  shows the fixed, and flush mount, idler base  31 . 
     The invention having been disclosed in connection with the foregoing variations and examples, additional variations will now be apparent to persons skilled in the art. The invention is not intended to be limited to the variations specifically mentioned, and accordingly reference should be made to the appended claims rather than the foregoing discussion of preferred examples, to assess the scope of the invention in which exclusive rights are claimed.