Universal wiring harness formboard
BACKGROUND OF THE INVENTION 
     With the increasing complexity of electrical wiring systems in a myriad of applications, especially airplanes and in the aerospace field, existing wiring harness making technology is advancing. The instant inventor, for example, has developed a computerized system for entraining the various types of wires used in a wiring harness around the pins of the wiring board substantially without human imput. This is not the only system for automatically threading the wires of a harness that has been developed, or is currently being developed. Because of the enormous complexity of these harnesses and their component harnesses, the expense of their creation is forcing manufacturers, and government purchasers of the manufactured equipment, to search for cheaper ways of creating the harnesses. Harness creation is an ideal area for the development of computer application, utilizing robot equipment which can be computer driven to any pre-set combination of locations, so that harnesses can be made by the computer directed robot, with the program being changeable at will for the creation of a different harness. 
     Such a system is particularly ideal for applications in which only a limited number of harnesses of any one type may be required, such as in the aircraft industry. The flexibility inherent in computer-operated harness making equipment is obvious. 
     However, whereas the computer data necessary to drive such a machine would be a simple matter, the mechanical interfacing required for the precise engagement and threading of numerous wires of different sizes and strengths, with different terminals, is naturally expensive and is in the developmental stage. 
     The other part of the harness making operation is the formboard on which these machines, or manual operators, actually create the harnesses. Currently, it is common practice for the manufacturer to have a permanent pegboard with the pegs at the appropriate positions with information indicating what types of wires are required and what type of terminals are needed. These boards are bulky when the enormous number that are needed in many manufacturing operations is considered. There is a storage problem, a problem of loss, breakage, and wear on the board surface. As a natural companion to the programmable wire threading machines used to create the actual harness, there is a need for a universal formboard which can be adapted to form any harness. 
     SUMMARY OF THE INVENTION 
     The instant invention provides the above-stated universal formboard, which can be changed in just a few minutes from any style harness pattern to any other style harness pattern. It is of modular construction, with one module comprising a panel having a work surface with a grid of bores therethrough through which extend the pins forming the pattern for the harness. The pins have heads so that they can never be pulled completely through the panel, and a back wall spaced rearwardly of the panel limits the rearward motion of the pins so that they cannot fall out of the bores completely, but they can be retracted beneath the working surface of the panel. 
     When the module is turned upside down, the pins will fall through the bores in the panel to extend as harness making pins. Inasmuch as only selected pins are desired to extend from the working surface, a pattern sheet, of Mylar or similar durable material, is fastened to the front of the panel. This sheet has holes punched where the selected pins are to extend, so that when the board is turned upside down only the selected pins protrude. While in this position, a locking mechanism comprising a sliding panel just behind the pin heads as they occur when in the extended position, slides to prevent return of these selected pins when the board is righted. 
     The modules are mounted singly, in pairs, or four at a time, or even more, to a clamp that engages a horizontal bar on a rack, which permits the selection of modules to be rotated upside down at will, and subsequently returned to an angle selected by the harness maker to be the most comfortable and convenient. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of the universal formboard; 
     FIG. 2 is a plan view of a typical pattern sheet; 
     FIG. 3 illustrates the wire retainer which holds the pattern sheet in place on the formboard; 
     FIG. 4 is a section taken along line 4--4 of FIG. 1; 
     FIG. 5 is a typical section showing the horizontal bar in phantom; 
     FIG. 6 is a detail illustrating the approximate relation of the lock sheet to extended and retracted forming pins; 
     FIG. 7 illustrates the module of FIG. 1 as it appears mounted on its horizontal bar and rotating back into the harness making position; 
     FIG. 8 is a perspective view of the rack showing the module thereon; 
     FIGS. 9-12 illustrate the various combinations of modules and their positioning on the horizontal bar; 
     FIG. 13 is a detail showing two adjacent modules mounted together; 
     FIG. 14 is a section through portions of the board illustrating the locking sheet drive eccentric in elevation; and 
     FIG. 15 is a plan view of fragments of the locking sheet illustrating the guide pins and the eccentric drive. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Overall construction of the formboard can thus be understood by reference to FIG. 4. The main panel is actually a sandwich 10 made of aluminum sheets 12 bonded to spacers 14 which extend the length of the board. The sheets 12 have holes 15 which align between the sheets to define the equivalent of a grid of bores best seen in FIG. 1, each bore defining a pin. Spaced to the rear of the front sheet of the panel 10 is a rear wall 16 which is spaced sufficiently to let the pins fall back on their heads clear of the work surface 18 of the panel. All of the pins shown in FIG. 4 are in the retracted mode, and are clear of the work surface. It should be noted that the rear wall is sufficiently close to the panel to prevent the pins from falling out of their bores. The panel 10 and the rear wall 16 are held together by frame structure 20, the details of which are not of importance to the invention as claimed. 
     Applied across the work surface of the panel 10 is a pattern sheet 22, which is shown in isolation in FIG. 2. The pattern sheet is designed to accommodate a particular harness pattern as indicated in phantom at 24 in FIG. 2. The pattern sheet is solid except for a very few holes 26 which are punched through the pattern where the pins should be to make the selected harness. 
     The Mylar pattern sheet is held in place by two wire frames 28 which are in turn held against the Mylar by clamping bar 30 and by bolts which engage the detents 32 in either end of the frame. This hold down means is not necessarily exclusive, and could be replaced for example by vacuum hold down, magnetic sheet retention, or any other suitable system. 
     When the pattern sheet is in place, the whole board is inverted on a horizontal bar 34 as shown in FIGS. 7 and 8. This bar is mounted on a rack or frame 36 and is preferably vertically adjustable as indicated in FIG. 8 so that it may be custom positioned by the operator. 
     When in the inverted position, as best shown in FIG. 5, the selected pins 38 which are permitted to pass through the holes 26 in the pattern sheet drop until their heads are stopped by the rear layer of the sandwich panel 10. The remaining pins 40 in FIG. 5 remain in the retracted position. It should be noted that although the extension of the pins into their erect position shown at 38 in FIG. 5 is accomplished by gravity through the inversion of the board in the preferred embodiment, any means of applying a releasible force to all of the pins, concommitantly or even consecutively sequentially, could be used. For example, a magnetic field could replace the gravitational field, either en masse or as individual cylinoid-like units at each pin station or, a mechanical actuation system, even hand drive, could be used. 
     Once in the inverted position with the selected pins extended, a means is needed to lock these pins in that position so that when the formboard is righted, the selected pins will not fall back into the retracted position. This is accomplished by the lock sheet 42 which is spaced behind the rear sheet of the panel 10 by spacers 44 and held in place by their engagement at the edges 46 and by L-beams 48 which span the unit. The locking sheet has holes 50 therein which align with the pin stations and are sized to permit the passage therethrough of the heads of the pins, which of course is necessary to achieve the configuration of the pins 38 in FIG. 5. Once in this position, however, a slight adjustment to one side to misalign this sheet with the pin stations results in the configuration of FIG. 6. Although the holes 50 may or may not lock the shafts of the pins 40 which are retracted (it probably does not matter), they do engage a portion of the pin head as shown in FIG. 6 to prevent its separation and return into the retracted position. 
     Although obviously there are a number of ways in which the movement of the lock plate can be accomplished, in the illustrated embodiment, best shown in FIG. 14, a rotating shaft 52 operated by a screw driver rotates the eccentric barrel 54 which rides in the slot 56 in the locking sheet, best shown in FIG. 15. Powered means remotely operated could also be used. Orthogonally oriented slots 58 guide the locking sheet on the guide pins 59, which are of construction similar to the eccentric shaft 52, but there is no eccentric. As the eccentric is rotated, it can be seen from FIG. 15 that, orientation taken from that figure, the locking sheet will move up and down, corresponding to movement from the position shown in FIG. 5 to that shown in FIG. 6. 
     After the locking sheet is locked, the board is righted, to the position shown in FIG. 6, as illustrated in FIG. 7. At this point the pattern sheet can be removed, if desired, or in some instances it may be desirable to leave it on the board, as necessary harness forming lines and notes may appear on the Mylar. 
     The units can be used singly as shown in FIG. 8, or, inasmuch as they are modular in nature, can be grouped in a number of ways as indicated in FIGS. 9-12. Like tiles, any side can be joined to any side of any other module. A pair of clamps 60 releasibly engage the bar 36 as shown in FIG. 4. Knobs 62 permit the release of pressure and rotation of the board. A bracket 64 connects the clamp to the sides of the modules as shown in FIG. 4. In the event two boards are used such that one is above the other, the bracket plate 64 spans the two. In case the panels are used alongside one another horizontally, a pair of brackets engages between the two as shown in FIG. 13. Construction is such that the spacing between adjacent pins is maintained the same across the gaps between two adjacent modules as shown in FIG. 13. In actual practice, this spacing has been set at one inch. 
     The formboard is truly universal, being adapted to any configuration wherein a planar work surface is required with periodic, spaced pegs for the actual entraining of the wire. The pattern sheets can be stored in a compact, easily cataloged manner, with new patterns being very simply made by special hole punch right on the working surface of the formboard. In current models, the board can be expanded from a single two-foot by three-foot module, to an array nine feet long and four feet tall. Because it is rotationally and vertically adjustable, harness makers do not have to conform to a pre-set height and orientation of formboard, but may adjust the board to their own liking. Although much discussion has involved a person as the actual harness maker, as stated above, the machine is equally adapted for use by automated harness makers, and provides a suitable complement to the programmable harness making machine. 
     While the preferred embodiment of the invention has been described, other modifications may be made thereto and other embodiments may be devised within the spirit of the invention and the scope of the appended claims.