WO2003031094A1

WO2003031094A1 - Projection wire harness routing table system

Info

Publication number: WO2003031094A1
Application number: PCT/US2002/032517
Authority: WO
Inventors: Steven P. Kaufman; Arkady Savikovsky
Original assignee: Laser Projection Technologies, Inc.
Priority date: 2001-10-11
Filing date: 2002-10-11
Publication date: 2003-04-17
Also published as: AU2002332110A1; WO2003031094A8

Abstract

A reusable table and method for laying out wiring harnesses and associated connectors for use in aircraft and the like uses a sheet of a structural material as a routing table (12'). A projector (14) is positioned to project a desired wiring pattern (16') onto the table that is visible from the top side. The table has formed over its upper face a set of holes adapted receive pins (22) that extend above the upper face of the table to position and /or secure one or more wires and associated hardware on the board. The projected pattern guides the population of the table with pins for each different wiring harness. In a rear-projecting form, the sheet is light-transmitting and the projector is disposed to project the pattern onto the lower face of the sheet.

Description

PROJECTION WIRE HARNESS ROUTING TABLE

SYSTEM

Background of the Invention

This invention relates in general to assembly jigs and methods, and more particularly to a reusable routing table and assembly method for wire harnesses used in transport vehicles, particularly aircraft.

In the manufacture of aircraft and the like, electrical wiring and associated "features", such as connectors, mounting brackets and other hardware, are assembled on a plywood routing board, typically 4 feet by 8 feet, or a side-by-side array of such boards for larger harnesses. Each wiring harness is unique to one aircraft, and can even be unique to one version of that aircraft. Often, it must fit perfectly into a matching space in the aircraft. The pattern of the harness is depicted on the board by a pattern of colored tapes adhered to its upper face. Assemblers also have written instructions telling them, for example, the number, type (e.g. coaxial for high frequency signal transmission, or fiber optic vs. metallic wire), and gauge of "wires" that run from a certain type of connector at a certain point to some other point or piece of hardware. Wires are guided along a selected, usually tape-marked path, by nails, pegs, or equivalent members secured to the board at appropriate points, e.g. where a wire bundle changes direction, is wrapped to secure it, or is terminated in a connector. In production, if a board is not in use, it is usually stored on the shop floor. Where multiple aircraft are in production, the boards not presently in use take up significant shop floor space.

For safety reasons, the U.S. Federal Aviation Agency (FAA) requires that all such wiring harness boards for all aircraft be kept for twenty years after the cessation of production of aircraft using that particular wiring harness. As a result, acres of warehouse space are now devoted to the storage, and possible later use, of thousands of 4 x 8 boards with projecting nails and taped wiring patterns. The cost of this warehousing over decades is substantial. There has therefore been a long felt need for a universal jig that can be used to manufacture wiring harnesses to the close tolerances required to assemble the completed harness into the constricted space aboard an aircraft. Such a universal jig must be reusable, while at the same time allowing any given harness to be accurately reproduced.

Some known harnesses are back-wired with mating connectors on the back or underside of the board, e.g. mating connectors for testing. Present boards can have dedicated test connectors. The assembled wiring harness is tested in place on the board, either on line, after assembly, or off-line at some later time.

To date, all aircraft manufacturers continue to assemble wiring for aircraft on wooden boards permanently marked with one wiring pattern for one specific harness. Warehousing costs continue to increase daily.

It is therefore a principal object of this invention to provide a universal, reusable routing table system and method for the assembly of wiring harnesses. Another principal object is to obviate the need to warehouse actual plywood routing boards for each unique harness.

Another principal object of this invention is to provide the foregoing advantages while not restricting the activity of workers assembling a wiring harness. Another object is to render these advantages while also accommodating back- wiring and testing of the wiring harness assembly in place on the board.

Summary of the Invention

A re-usable system and method for assembling a variety of wiring harnesses according to a predetermined pattern, storing the pattern, and selectively recalling and re-using the pattern of any given wiring harness uses a routing table. In one form, this table is a light-transmitting, preferably translucent, sheet. A light projector operates to project a light pattern onto the table so that the desired wiring pattern is visible on the upper surface of the table. This light pattern guides the population of the upper surface of the table with multiple pins that in turn guide and/or secure components, that is, features, such as connectors and mounting brackets secured to the board with locking or friction-fit pins, and wires. The system and method can project the entire pattern at once, or it can project the pattern in sequential parts, e.g. first sharing the location of the features, and then the wiring held, guided by, or connected to the features. In a rear-projection embodiment, the table is translucent and the projector is disposed under the table. In an overhead projector form, the table is not necessarily translucent or transparent. The board is formed of a flat sheet of a suitable structural material with pin- receiving holes covering the upper face of the board at regular intervals. In one form, the board can be opaque. In a rear projection form, it is a sheet of light- transmitting material, e.g., a plastic. The plastic can be a two-piece laminate of the same material. A thicker, e.g. one-quarter inch, board, has the array of holes drilled through it, and a thinner board, e.g. one-sixteenth inch, is sold and bonded to the underside with an adhesive of a matched index of refraction, or simply clamped together. The lower laminate sheet supports pins dropped into selected holes, where they are replaceably held at their lower ends. The light projector can be a raster scan or LCD projector, but preferably is at least one laser projector, e.g., one with a 60° optical projection angle.

Wires and features can be mounted to or fixed in standardized L-shaped mounting brackets that are secured to holes in the upper face of the board by locking or friction fit pins. An octopus harness can also be located to one side of the board for testing connections and to circumvent back- wiring where it would otherwise be used. The octopus harness has multiple wire and connectors interconnected through it to connectors and wires assembled on the board and outside components such as a power source, test circuitry, etc.

The pins are replaceable and relocatable on the board to accommodate different wiring harness manufacture under the guidance of different projected light patterns. To retain a harness routing "board" to meet FAA requirements, one retains the stored program used to control the projector display of a given pattern. These and other features and objects of the invention will be more readily understood from the following detailed description of the invention which should be read in light of the accompanying drawings.

Brief Description of the Drawings

Fig. 1 is a view in perspective of an overhead projector wiring harness routing table;

Fig. 2 is a view in perspective of a rear projection wiring harness routing table and method according to the present invention; and Fig. 3 is a detailed view in perspective, with portions broken away, of a replaceable mounting bracket for use in the system and method of the present invention.

Detailed Description of the Invention Fig. 1 shows a wiring harness routing table system 10 of the present invention that includes a table 12', an overhead projector 14', a projected laser light pattern 16 projected onto an upper face 12a' of the table 12', and a monitor and associated computer 18. The projector 14' is preferably a laser projector. The monitor displays the projected pattern 16' as controlled by software being run on the computer. The software in turn controls elements of the projector that direct the light beam output of the projector 14' to trace out the pattern 16. The board in this arrangement can be an opaque sheet of plywood or the like, or a translucent plastic sheet, or the like.. The pattern 16' shown is a highly simplified form, shows connectors Jl ... J4 and paths along which bundles of wire are laid out to create an assembled wiring harness according to this pattern. As noted above, as the table 12' is typically four feet by eight feet and the pattern is often detailed and dense, the projector is spaced from the upper face 12a of the table a sufficient distance, given the projector, the board size, and the nature of the pattern, to produce a clear, and accurately sized pattern to produce the harness. While Fig. 1 shows multiple rays 20 of projected light, it will be understood that with a laser projector this projection is actually one narrow beam that is traced out over the board at a very high speed. The overhead projector 14' can project at an angle, more from a side than directly overhead, in order to control the problem of workers blocking the projection.

Fig. 2 illustrates a wire harness routing board system 10 and method of the present invention in another, rear-projecting, form. (Like parts in Figs. 1 and 2 use the same reference numbers, but those in the overhead projection embodiment are primed.) This embodiment follows the standard approach of using a table 12, but it is light-transmitting, not opaque. Further, the projector 14 is an optical projector, and as presently preferred, a wide projection angle laser projector, but it is located beneath the table 12 for rear projection onto the lower face 12b of the table 12. As in Fig. 1, the projected rays 20 create the light pattern 16 on the table. (Depending on the thickness of the table, the software controlling the projection may need to compensate slightly for parallax effects that occur, particularly at the larger projection angles, as the light traverses the table with varying degrees of incidence and varying lengths of travel through the material of the table.) A worker standing next to the table 12 can look down onto it and see the pattern 16 displayed thereon. In working on the table to place and assemble components in accordance with and guided by the pattern, the worker, wires, features, or tools do not block the projection to any extent greater than conventional colored tape path markings would be blocked or obscured.

While a single wide angle projection laser projector 14, 14' is presently preferred, other optical projection techniques such as raster and LCD projectors can be used. In addition, it is possible to use multiple projectors, each projecting a portion of the pattern 16, or to used auxiliary optical systems such as ones using fixed and scanning reflective or refractive elements to direct or to scan the projected pattern 16. The exact pattern used for any given application is software controlled as with any known laser projection system 14, 18. The projector 14 for use in the present invention is preferably one or more high speed laser projectors sold by Laser Projection Technologies, Inc. of Londonderry, New Hampshire under the trade designations "LPT" and "LPT-2" (a smaller, more compact, and more portable version of the LPT projector). The software preferably gives the operator the option of projecting the entire pattern 16 projected by the associated projector 14, or selected portions thereof. In particular, it is often desirable to first project the pattern of the features, and then the pattern of the wires.

In the system and method of the present invention, the projected light pattern 16 guides a worker in populating the table 12 with pins 22 and features — such as mounting bracket 30 (Fig. 3) and known connectors and other equipment that can be secured in place on the table 12 by the brackets 30. Only two pins 22 are shown, but it will be understood that the board will typically have numerous pins 12 positioned as dictated by the pattern 16, typically at pivot points where a wire or bundle of wires 24 changes direction, or such wire or bundles of wire is wrapped, as shown, or connected to a connector, mounting bracket, or other feature. It will be understood that as used herein, "wire" is defined broadly to include a single wire, bundles of wires, metallic wires, co-axial transmission lines, and all varieties of optical fibers. The upper face of the table 12 has formed therein an array of holes 26. The holes are preferably uniformly mutually spaced, e.g. 1 inch center-to-center measured lengthwise or across the width of the table 12. The spacing of the holes 26 is selected so that when any one of the multiple patterns 16 used to make wiring harnesses is projected, pins can be placed at appropriate points to execute the wiring design. (As illustrated, there would usually be a pin 22 (not shown) at each right angle turn of the wire 24, and therefore an associated hole 26.) The pins are preferably held in the holes by gravity and/or a slight friction fit.

The holes 26 are also, therefore, preferably closed-bottom with the pin resting on the bottom, but, of course, a wide variety of alternative arrangements are possible. For example, the holes can be drilled through the table 12 and the pins can have an axially projecting boss at at least one end that seats on an associated hole with a shoulder engaging the upper face 12a of the table. While the hole 26 and pins 22 are shown in Fig. 2, it will be understood that they are also used in the overhead projection form of Fig. 1.

Fig. 3 shows the mounting bracket 30 suitable for use in the present invention. Instead of pins 22, locking or "tight" friction-fit pins 23, 23, are inserted through openings in a base portion 30a and into underlying ones ofthe holes 26. The mutual spacing ofthe pins 23 is set to match that ofthe same integral number of hole-to-hole spacings ofthe associated table 12 in the system. An upright plate 30b has a U-shaped central opening 30c that can receive and cradle a wire 24 (including a bundle of wires). Holes 30d are designed to receive screws, pins, or other known fasteners that connect to, and secure in a light-guided location on the table 12, some features such as a standard connector, whether electrical or optical.

The table 12 is shown as a single solid piece of material. In the Fig. 2 rear- projection form, it can be a single sheet of a plastic such as a Plexiglas® brand acrylic sheet. It can also be formed of a laminate of two such sheets, an upper one carrying the array of holes 26 and a lower one that is solid and provides a floor to hold the pins 22 when they are inserted in the holes 26 as guided by the projected light pattern 16. By way of illustration, but not of limitation, the upper laminate sheet can have a thickness of 1/4 inch, and the lower laminate sheet can have a thickness of 1/16 inch. The sheets can be simply clamped together, but to control the loss of light and refraction at internal plastic-air interfaces, they are preferably bonded with a suitable adhesive, e.g. one that is light- transmissive when cured and having an index of refraction selected to generally match that ofthe material forming the table 12.

While the invention has been described with respect to a pins-in-hole array system for translating the light pattern into guides for manufacture ofthe actual wires and features into a wiring harness assembly, it will be understood that other arrangements are possible and will occur to those skilled in the art, e.g. replaceably adhering guide members to the upper face 12. In each instance, however, placement of such members and the wire harness fabrication are guided by the projected light pattern 16. These and various other modifications and alterations will occur to those skilled in the art. Such modifications and alterations are intended to fall under the scope ofthe appended claims. What is claimed is:

Claims

1. A reusable wiring harness table comprising a sheet of a structural material having upper and lower faces, a projector disposed to project a light pattern onto said sheet that is visible when viewed at said upper face, a plurality of guide members adapted to be held in positions on said upper face at positions selected in combination with said hght pattern to guide the assembly ofthe wiring harness on said upper face, and means for replaceably holding said guide member and said upper face.

2. The reusable wiring harness table of claim 1 wherein said means for holding comprises a plurality of holes formed in said upper face of said sheet and said guide members are pins each having a portion adapted to be received in one of said holes.

3. The reusable wiring harness table of claims 1 or 2 wherein said sheet material is light-transmitting and said projector is disposed to direct said projected light pattern onto said lower face.

4. A method of fabricating a wiring harness comprising, providing a board with upper and lower faces, populating the board on said upper face with guide members in locations indicated by said wiring harness light pattern, projecting a wiring harness pattern onto the board that is visible at said upper face, and locating wires and associated features ofthe wiring harness on said board upper faces guided by said hght pattern.

5. The method of claim 4 wherein said board is formed of a light-transmitting material and said projection is onto said lower face.