Wire harness assembly fixture retainer holder and detector

An apparatus for ensuring the proper existence and location of wire harness retainers along the length of a wire harness is provided. The apparatus is adapted to receive a wire harness retainer and, once the retainer is inserted, to generate a signal indicating the retainer has been inserted.

BACKGROUND OF THE INVENTION 
1. Technical Field 
This invention relates generally to an apparatus for providing positive 
recognition that a device to be retained is properly seated in its 
retainer, and, more, particularly to an apparatus for ensuring the wire 
harness has the proper number of retainers, and further for ensuring that 
these retainers are located at the proper intervals along the length of 
the harness. 
2. Discussion of the Related Art 
Wire harnesses, while appearing to be a relatively simply item, are often 
difficult to assemble. The number of wires involved, the manner in which 
the wires are bundled and branched from the main harness, the types of 
terminals that must be attached to the wires, and the number of harness 
retainers that must be secured to the harness greatly increase the 
complexity of the assembly task. As used throughout this discussion, a 
"wire harness" is a bundle of wires that is taped, sheathed or otherwise 
bundled together for routing between multiple points on a vehicle, such as 
an automobile; a "terminal" is a metal connection point between a wire and 
a connector housing; a "connector" is an interconnecting device attached 
to a terminal or group of terminals to facilitate the connecting of 
wire(s) to components or to other wires; "bundles" and "branches" within a 
wire harness are subgroupings of wires that are segregated from the main 
grouping of wires of the wire harness, usually to allow routing to 
separate areas, or to allow connection to terminals; and "retainers" are 
retention devices usually affixed to the wire harness at predetermined 
intervals along the length of the wire harness, where the retainers 
facilitate securing the wire harness along its routing path through the 
vehicle. 
While many complex assembly tasks are now being handled by automated 
machinery and robots, the task of assembling wire harnesses often proves 
too complex to easily automate. Therefore, wire harnesses are largely 
manufactured by hand. However, the complexity of assembling a wire harness 
can often be a difficult task for the non-skilled and semi-skilled workers 
who frequently work on the assembly line. For these workers, the monotony 
of the task and the small size of the wires and terminals increases the 
likelihood that they may make an inadvertent error while assembling the 
wire harness. To aid the worker in properly assembling wire harnesses, a 
variety of fixtures and test devices have been fashioned. 
There are several critical measurements of wire harness integrity, some of 
these being harness continuity, retainer presence and retainer 
positioning. Harness continuity is checked by determining if there is 
electrical continuity between each end of the harness. Usually this is 
done by connecting the connectors found along the wire harness to test 
connectors. An electrical current is then passed through the harness and 
is checked to see if it reaches the other end of the harness. Generally, 
the continuity check interrogates not only end-to-end wire circuit 
integrity, but also ensures that each wire-to-terminal connector 
connection is in the proper position. It is important to check continuity 
to ensure that the harness completes the proper electrical connections 
when mounted in the vehicle. Ensuring all of the retainers are present 
helps ensure that the wire harness is capable of being properly attached 
to the vehicle. Finally, retainer positioning along the wire harness is 
checked to ensure that all the required retainers are present, and that 
the retainers are also located at the proper intervals along the harness. 
It is important that all of the retainers be located at their proper 
intervals along the wire harness to ensure that they will mate with their 
corresponding receptacles on the vehicle to properly secure the wire 
harness to the vehicle when installed. 
Ideally, it would be most efficient to be able to check for wire harness 
continuity, retainer presence and the interval positioning of the 
retainers in the same operation. Many different types of fixtures exist 
for checking wire harness continuity, but few currently exist for checking 
for retainer presence and retainer position intervals. 
SUMMARY OF THE INVENTION 
It is therefore an object of the present invention to provide an apparatus 
for checking for the presence of wire harness retainers and for checking 
retainer interval location in a single operation. This apparatus of the 
present invention is suitable for integration with existing wire harness 
continuity checking fixtures, or can be used by itself. This apparatus 
includes at least one retainer holding and detection device into which the 
retainer is inserted. The insertion of the retainer into the holder causes 
a detection signal to be generated by the detector. Ideally, there is one 
holder and detector for each retainer, and each holder and detector is 
located to coincide with the proper location of a retainer. When detection 
signals are generated by every detector, that means that all of the 
retainers are present and in their proper position. When combined with a 
wire harness continuity test fixture, the receipt of detection signals 
from every detector can be made to be a precondition to the generation of 
a satisfactory continuity check signal. One feature of the present 
invention is that the holder and detector is readily adapted to receive a 
variety of retainers without requiring significant modification. That 
allows the holder and detector to be used with many different types of 
wire harness retainers. One advantage of the present invention is that the 
integration of the holder and detector with a wire harness continuity test 
fixture can be accomplished with little added circuitry. Another advantage 
of the present invention is that the holder and detector can be made from 
inexpensive materials.

DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENT 
As shown in FIG. 1, the present invention is adapted for the testing of 
wire harnesses during and after the assembly process. The wire harness 10 
includes many different wires 13, 15, 17 bundled together in one or more 
grouping. The wires 13, 15, 17 are grouped to facilitate routing the wires 
within a vehicle, such as a car. As shown in this exemplar wire harness 
10, there are some main trunks 20, 22 and several major branches 30, 33, 
35, 38, 40, 45, 48, 50 in this harness 10, with several different 
connectors 60, 63, 65, 68, 70, 73, 75, 78, 80 that interconnect various 
electrical components and wire segments (not shown) to the harness 10. As 
shown here, there are several semi-rigid sections 20, 22 with flexible 
elbows 82, 85, 88, and several other semi-flexible sections 30, 33, 35, 
38, 40, 45, 48, 50 sheathing the harness. While not critical to the 
understanding of this invention, the semi-rigid sections 20, 22 are formed 
from plastic tubing with a longitudinal slit extending the length of the 
section. The slit allows wires to be placed inside the tube sheathing. The 
semi-rigid sections 20, 22 may also have take-out holes 90, 93 at various 
places along the length of the tube sheathing. The take-out holes 90, 93 
allow smaller sections of wire 95, 98 to branch out of the tubing. The 
semi-flexible sheathing sections 30, 33, 35, 38, 40, 45, 48, 50 are formed 
by wrapped adhesive tape around the wire harness 10. This task is usually 
accomplished manually by factory workers. The sheathing of wire harnesses 
in semi-rigid and semi-flexible casings is well known in the art, and need 
not be discussed in any greater detail to understand the invention at 
hand. 
The wire harness sheathing. (i.e. the semi-rigid sections 20, 22 and the 
semi-flexible sections 30, 33, 35, 38, 40, 45, 48, 50 serves several 
purposes. One primary purpose of the sheathing is for facilitate the 
routing of the wire harness 10 through the vehicle. If the wires 13, 15, 
17 were left loose, it would be difficult to route the harness 10 through 
the vehicle because the loose wires would tangle with each other and with 
other items found on vehicles. Another purpose of the sheathing is that it 
facilitates the segregation of wires for attachment to the connectors 60, 
63, 65, 68, 70, 73, 75, 78, 80. By its nature, the sheathing presents for 
attachment only those wires which extend out from the sheathing, either at 
take-out holes 90, 93 or at the ends of the sheathing sections 100, 103, 
105, 108, 113, 115, 118, 120, 122, 125, 128, 130, 133, 135, 138, 140. For 
example, as shown in this exemplar, the wires from take-out hole 90 are 
wrapped by the adhesive tape to form a semi-flexible sheathing section 43; 
the wires enter the sheathing at one end 95 and emerge from the other end 
100 for attachment to the terminals in connector 65. Another purpose of 
the sheathing is to protect the wires of the wire harness 10 from 
abrasion. Because wire harnesses must often be routed through small access 
holes in thin metal walls, the risk of scraping or cutting the wires as 
they pass through the vehicle access holes is reduced by encasing the 
wires in a protective sheathing. Also, the sheathing reduces the 
likelihood that wires will kink or be bent sharply as the wire harness is 
routed along the vehicle. Another purpose of the sheathing, and the 
purpose directly related to the present invention, is to facilitate the 
attachment of the wire harness 10 to the vehicle along its routing path. 
This is accomplished by providing retainers, or attachment points, at 
various points along the length of the wire harness. 
As shown in FIG. 1, the wire harness 10 has various retainers 200, 203, 
205, 208, 210, 213, 215, 218, 220, 223, 225, 228, 230, 233, 235, 238, 240, 
243, 245, 248, 250, 253, 255, 258, 260 located at various points along the 
length of the semi-rigid 20, 22 and semi-flexible 30, 33, 35, 38, 40, 45, 
48, 50 sheathing sections. As can be better seen in FIGS. 2 and 3, the 
retainers can take a variety of forms. Here, as shown in FIG. 2, there is 
a "christmas tree" type retainer 300 attached to a semi-flexible section 
310 of sheathing by being wrapped 313 in the adhesive tape along with the 
wires 315; and, as shown in FIG. 3, a channel-type retainer 320 is formed 
along the sidewall of a section of semi-rigid sheathing 330. The christmas 
tree retainer 300 is a common type of wire harness retainer used to mate 
with a mounting hole formed in the vehicle body. Likewise, the channel 
retainer 320 is a common type of retainer used to slide over the heads of 
body panel screws and bolts to mount the wire harness to the body. Many 
other types of retainers are commonly used in the industry, and need not 
be specifically cataloged here to understand the invention. One common 
feature underlying all retainers, regardless of their form, is the purpose 
they serve: to provide an attachment point between the wire harness and 
the vehicle body for supporting and positioning the wire harness along its 
routing path. 
As shown in FIG. 1, the retainers 200, 203, 205, 208, 210, 213, 215, 218, 
220, 223, 225, 228, 230, 233, 235, 238, 240, 243, 245, 248, 250, 253, 255, 
258, 260 can be used not only to secure the wire harness when it is 
installed in the vehicle but also to secure the wire harness in position 
during assembly and testing. To accomplish holding the harness during 
assembly and testing, holders are provided 350, 353, 355, 358, 360, 363. 
These holders are adapted to receive the retainers 200, 203, 205, 208, 
210, 213, 215, 218, 220, 223, 225, 228, 230, 233, 235, 238, 240, 243, 245, 
248, 250, 253, 255, 258, 260, and are located along the surface of the 
assembly work table in positions to coincide with the desired locations of 
the retainers. It should be appreciated that, as shown in the exemplar in 
FIG. 1, there may be holders for each of the retainers, or, as shown here, 
there may be holders for only a select number of retainers. Also, it 
should be appreciated that holders may be provided simply for the purpose 
of securing the harness during assembly, or simply for the purpose of 
testing the harness during assembly, and need not serve the dual purpose 
of securing the harness during assembly and during testing. The driving 
factor behind whether or not holders need be provided for each retainer is 
whether the holders are being used to secure the harness for assembly, 
whether it is determined to be necessary to secure the harness at each and 
every retainer during the assembly procedure, whether the holders are 
being used to assist in testing the harness, and whether it is determined 
to be necessary to ensure the location of each retainer as part of the 
testing procedure. Thus, one of ordinary skill in the art can appreciate 
that the generalized discussion presented here is for the purposes of 
illustrating the concepts of the invention, and should not be construed as 
being the only manner in which the invention can be practiced. 
As set forth in this preferred embodiment, the holders 350, 353, 355, 358, 
360, 363 serve to determine whether certain key retainers 200, 203, 205, 
208, 210, 213, 215, 218, 220, 223, 225, 228, 230, 233, 235, 238, 240, 243, 
245, 248, 250, 253, 255, 258, 260 are in their proper locations, and also 
serves to integrate the checking of retainer location with the wire 
continuity test performed on the harness at the end of the assembly task. 
Specifically, at the end of the assembly task, the wire harness 10 is 
secured by its retainers to the holders, and the various connectors are 
connected to the test connectors 400, 410. Although, in this exemplar, not 
all of the test connectors necessary to conduct a complete end-to-end wire 
harness continuity test are shown, one of ordinary skill in the art can 
appreciate that it would be necessary to have a mating test connector for 
each wire harness connector to conduct a full end-to-end wire harness 
continuity test. In order for the end-to-end continuity test to generate a 
"passing" or "satisfactory" signal result, there must be continuity along 
each wire between every connector terminal. For example, if a particular 
wire is supposed to be connected to the fifteenth pin terminal of 
connector 68 at one end and to the fourth pin terminal of connector 78, a 
signal sent from terminal pin fifteen of the test connector attached to 
connector 68 should reach terminal pin four of the test connector attached 
to connector 78. This type of electrical continuity check would be 
conducted for each wire in the harness. If all the wires had proper 
continuity, the continuity test result would be "passing" or 
"satisfactory". 
The holders 350, 353, 355, 358, 360, 363 in this embodiment, as can be 
better seen in FIGS. 4, 5, 6 and 7, include a holding element 500 and a 
detecting element 510 mounted to a base 520. The holder 500 is secured to 
the base 520 by screws 525, 527. As shown in these figures, the holding 
element 500 is adapted to receive a christmas tree retainer 300, like that 
shown earlier in FIG. 2. The holding element 500 has a channel 530 that 
allows the shank 540 of the christmas tree retainer 300 to clear the 
holder, while the flange lip 550 extending around the periphery of the 
channel 530 allows the base 560 of the christmas tree retainer 300 to 
slide underneath the holding element 500. The detecting element 510 in 
this embodiment is a slightly obtuse L-shaped strip of conductive metal. 
At rest, the detecting element is biased toward the holding element 500. 
When the retainer 300 is inserted into the holding element 500, the base 
560 of the retainer 300 causes the detecting element 510 to be deflected 
downward. The retainer 300 is thus sandwiched between the flange lip 550 
and the detecting element 510. 
As shown in FIGS. 4, 5, 6, and 7, the base 520 of the holder and detector 
is a block of plastic, in this case Celcon. The base 520 is approximately 
21/4" tall, 11/2" wide and 3/4" thick. The base 520 is machined to have a 
detecting element mounting channel 600 near the top along one side. The 
detecting element 510 is mounted to the base 520 by screwing 610 the base 
leg 620 in the mounting channel 600, which allows the deflectable leg 630 
to move freely toward the holding element 500. When deflected downward by 
the inserted retainer, the deflectable leg 630 contacts a contact pin 660 
mounted in the base 520. There is a 1/4" diameter vertical passageway 670 
drilled upward from the bottom of the base toward the top, and a contact 
pin mounting hole 680 is countersunk at the top end of that passageway 
into which the contact pin 660 is inserted. The pin 660 may be glued to 
help secure it in position. The terminal portion 700 of the contact pin 
660 extends downward into the vertical passageway 670, and has a wire 710 
attached to it. Another wire 720 is attached to the detecting element 510 
by sandwiching it between the base leg 620 and the detector base 520. 
Since the detecting element 510 is conductive material, in this case 
copper, deflecting the deflectable leg 630 downward onto the contact pin 
660 completes an electrical circuit between the two wires 710, 720. Thus, 
the detecting element 510 completes an electrical circuit when the 
retainer 300 is inserted into the holder 500. 
There are additional features of the holder and detector that will now be 
described. Besides having a vertical passageway 670, the base 520 also has 
a cross-wise passageway 800 and an oval access passageway 810. These 
passageways allow the wires 710, 720 to be routed toward the bottom, the 
front or back, or the sides, depending upon the manner in which the base 
520 is mounted. Recalling the earlier discussion, the retainers are 
designed to hold the wire harness along its routing path through the 
vehicle. It can therefore be appreciated that the retainers may be 
oriented in any number of ways. Some retainers may be aligned vertically, 
some horizontally, and so on. Recalling FIG. 1, the various holders must 
be capable of being aligned in a number of different ways to match the 
alignment of their respective retainers. Referring again to FIGS. 4, 5, 6 
and 7, it can be seen that a mounting base 820 is adapted to be screwed 
830 to the holder base 520. There are seven sets of mounting holes 850, 
860--two sets each on the front and back, one set on each side, and one 
set on the bottom--that are provided for receiving the screws 830. As 
provided here, the holder base 520 may be mounted to the mounting base 820 
in many different ways, as will be described in greater detail later. The 
mounting base 820 has a boss 870 through which the fixture post 900 
extends. The fixture post 900 is secured to the work table or surface to 
which the holder is desired to be secured. The fixture post 900 is secured 
within the boss 870 by a set screw 910. The fixture post 900 may include a 
wire retention collar 920 to secure the wires 710, 720 and help prevent 
the detector wires from being accidentally pulled or damaged. 
As shown in the functional diagram in FIG. 8, the holder and detector 
circuit can be integrated into the wire harness continuity test circuit 
earlier described. Specifically, for each holder and detector, a "retainer 
present" signal is generated every time the deflectable leg 630 is 
deflected downward onto the contact pin 660 to complete the electrical 
circuit between the two wires 710, 720. This can be functionally 
represented as signals D1 through Dn. When all of the retainers are 
inserted into all of their respective holders, each detector will generate 
a "retainer present" signal, and the electrical summing 1000 of each 
detection signal D1-Dn would generate an "all retainers present" signal at 
the output 1010 of the summer 1000. Likewise, when all of the connectors 
are connected to their respective test connectors, the end-to-end 
continuity test would return "electrical continuity OK" signals for each 
wire which satisfactorily passes the continuity test. This can be 
functionally represented as signals E1-En. If all of the wires have 
continuity, the electrical sum 1020 of these signals would result in an 
"all wires have continuity" signal 1030 at the output of the summer 1020. 
Here, since the retainer presence test and wire continuity tests are 
integrated, the "all retainers present" signal 1010 would be electrically 
summed 1040 with the "all wires have continuity" signal 1030 to produce a 
"wire harness is OK to ship" signal 1050. One of ordinary skill can 
appreciate that any number of variations of such a testing procedure could 
be implemented using these concepts. As will now be described in greater 
detail, the manner in which the holder and detector can be mounted with 
respect to the test table or work surface can be easily adapted to suit 
the alignment of the retainers of the harness being tested. 
As shown in FIGS. 9 through 17, the holder base 520 can be secured to the 
mounting base 820, and the mounting base 820 secured to the fixture post 
900, in a variety of different manners to accommodate the alignment of the 
retainers 950. For example, referring jointly to FIG. 4 and sequentially 
to FIGS. 9 through 17, the base 820 may be secured to the holder base 520 
using the mounting holes 850, 860 along one of the sides, and secured to 
the fixture post 900 to receive a retainer 950 oriented horizontally as 
shown in FIG. 9. Or the base 820 may be rotated 180.degree. and secured to 
the fixture post 900 to receive a horizontally aligned retainer 900 that 
is much closer to the work table surface, as shown in FIG. 10. Or the base 
may be aligned as in FIG. 9 but rotated about the fixture post 180.degree. 
to produce the alignment shown in FIG. 11. Or the mounting base 820 may be 
secured to the mounting holes 850, 860 located along the bottom of the 
holder base 520 to provide for receiving retainers aligned vertically, 
such as shown in FIGS. 12 and 13. Or the mounting base 820 may be secured 
to mounting holes along the front or back face of the holder base 520. 
This provides for the types of alignments shown in FIGS. 14, 15, 16, and 
17. The difference between the alignment shown in FIGS. 14 and 16 from 
that of FIGS. 15 and 17 is that the mounting base 820 is aligned along the 
vertical axis of the holder base 520 in FIGS. 14 and 16 and along the 
horizontal axis in FIGS. 15 and 17. 
Finally, as shown in FIGS. 18 through 34, the holder 500 can be formed to 
suit a variety of retainers. For example, the holder 500 shown in FIG. 18 
accepts a christmas tree type retainer as earlier described, while the 
holder of FIGS. 19, 20, 21 accept christmas tree type retainers having 
different shapes. To attach any of the different holders 500 to the base 
520, the screws 525, 527 are simply removed and the old holder is detached 
from the base 520. A new holder 500 may then be secured to the base 520 by 
the screws 527--the detector 510 need not be realigned or replaced. By 
providing for the variety of base alignments shown in FIGS. 9 through 17 
and by providing for the variety of holding elements 500 shown in FIGS. 18 
through 34, it can be appreciated that the holder and detector of the 
present invention can be readily adapted to suit whatever types of wire 
harness and retainers are present. Also, since the detector generates a 
"retainer present" signal whenever a retainer has been inserted into the 
holder, the holder and detector of the present invention provides a 
convenient means of testing to ensure all the required retainers are 
present on the wire harness. Also, because the holder and detector can be 
readily moved from fixture post to fixture post and can be aligned in any 
number of alignments with respect to the fixture post, the wire harness 
can also be readily checked to ensure that the proper spacing between 
retainers exists. When the holders are placed on the work table, such as 
in FIG. 1, in a pattern that mimics the attachment points along the 
routing path of the wire harness within the vehicle, inserting the 
retainers into the holders ensures the retainers will mate with their 
respective attachment points when the wire harness is routed in the 
vehicle. 
It can be appreciated that there may be other advantages of the present 
invention not enumerated in this description. Rather, the foregoing 
description of the presently preferred embodiment was provided for the 
purposes of illustration, and should not be construed to limit the 
invention. One of ordinary skill in the art can appreciate that a variety 
of modifications not described herein may be effected to the invention 
without departing from the spirit or scope of this invention.