A wiring harness shroud

Abstract: A wiring harness shroud comprising a tubular section (102) for enshrouding a wiring harness (106) to be inserted through an opening of a structural member during a manufacturing operation for producing a product including the structural member, said tubular section (102) having two ends, at least one of which is open to receive said wiring harness (106).

Description: The present invention relates generally to the installation of a wiring harness used for interconnecting electrical equipment and/or circuits and, more particularly, to a method and apparatus for dressing or enshrouding such a wiring harness for installation of the harness through an opening of a structural member during manufacture of a product including the structural member. The present invention is particularly applicable to the manufacture of motor vehicles and accordingly will be described with reference to that application. Wiring harnesses used for motor vehicle electrical circuits are normally preformed as a central bundle of electrical conductors. Projecting from the bundle at varying locations along its length are pigtails, takeouts, connectors, harness hold-downs and the like which may be referred to herein as extensions. The extensions serve to make connections from electrical circuits or equipment to or through the electrical conductors of the wiring harness to associated electrical circuits or equipment or to hold the harness in place in the motor vehicle. Oftentimes, preformed wiring harnesses must be routed through openings in structural members, for example through the firewall of a motor vehicle, to make the required connections. When a wiring harness is to be passed through an opening, the extensions tend to catch on the opening and interfere with quick and easy installation of the harness. Prior to this time, extensions from a wiring harness typically have been taped against the central bundle or trunk of the wiring harness to facilitate installation. Unfortunately, the application of tape to the individual extensions is a time consuming operation. An alternate wiring harness dressing arrangement involves the use of tubular "heat shrink" material. The extensions from the wiring harness are held against the harness trunk and a length of tubular heat shrink material is slid over the harness. Heat is then applied to the heat shrink material causing it to shrink or reduce in size and trap the extensions down to substantially the size of the wiring harness trunk. The dressed wiring harness is then inserted through an opening in a motor vehicle firewall or other structural element. Once fully inserted, the shrink wrap material is ripped from the wiring harness to release the extensions for the remainder of the installation of the wiring harness. Unfortunately, the application of heat shrink material to wiring harnesses requires substantial floor space, the application process is difficult to control, the application requires at least as much labour as taping and the heat shrink material is more expensive than tape. Further, there have been problems in removing the heat shrink material. Perforations have been formed in the heat shrink material to attempt to overcome the removal problem. However, even if perforations are provided, problems may persist since excessive heat can bond the perforated sections together. Of course, there is also the possibility that excessive heat will damage the wiring harnesses. US-A-4 891 256 discloses a device for wrapping round and bundling cables or the like after they have been installed which comprises an axially compressible, radially expansible tubular member made from a fabric of engineering plastic and axially split to define mating edges which are provided with means such as the two parts of a zip fastener by which they can be fastened together to secure the tubular member around the bundle of cables. There is still a need for an improved method and apparatus for dressing wiring harnesses for installation through openings in firewalls or other structural elements of motor vehicles and other products. Preferably the improved wiring harness installation/dressing method and apparatus would utilise inexpensive materials, be readily applied to and removed from wiring harnesses, and permit recycling or re-use of at least some of the apparatus to further reduce the expenses involved in wiring harness installation operations. This need is met in accordance with the invention by a wiring harness shroud comprising a tubular section of stretchable material for enshrouding a wiring harness, open at one end and having releasable closure means extending along at least part of its length, the tubular section comprising a generally rectangular piece of the stretchable material having its two long sides joined to one another by a closure means, wherein said closure means comprises a single thread chain stitch, the chain stitch being secured at one end of the tubular section by tab means which is forcibly removable to release the chain stitch and thereby open the tubular section. Such a shroud forms the subject matter of claim 1. The shroud serves to hold the pigtails, takeouts, connectors, harness hold-downs and the like which otherwise extend from the harness against the trunk of the harness. Thus dressed or enshrouded, the wiring harness can be extended through an opening in a firewall or other structural member of a motor vehicle or other product for installation of the harness. Once inserted through the opening, the shroud is removed by releasing the chain stitch which initially maintains the shroud as a tubular structure but can be removed to open at least a portion of the tubular structure to facilitate shroud removal. Thus the invention also provides a method of inserting a wiring harness including loose extensions projecting therealong through an opening of a structural member during a manufacturing operation to produce a product including the structural member which comprises the steps of enshrouding the harness by inserting it from one end into a tubular shroud member to contain the extensions within the shroud member, passing the enshrouded harness through the opening, and then removing the tubular shroud member from the harness, wherein the harness is inserted into a shroud as claimed in claim 1 and the chain stitch is released after the harness has passed through the opening so as to rapidly open the tubular shroud member. The shroud of the invention is made of a "stretchable material", which is intended to include without limitation stretchable cloth, elasticised cloth, a rubber product, cloth interwoven with elastic thread or other appropriately stretchable or stretchably reinforced material. Thus the tubular section of stretchable material may comprise cloth made of a two-way stretch blend including spandex. To facilitate installation of the shroud onto a wiring harness, the tubular shroud member may be expanded by positioning a tubular applicator therein, and then applied to the wiring harness by advancing the applicator and the wiring harness relatively to one another to transfer the tubular shroud member from the applicator to the wiring harness. Thus the shroud is initially stretched over a tubular applicator to expand the shroud. A wiring harness is then inserted into the tubular applicator and the shroud is slid off the tubular applicator onto the wiring harness as the wiring harness is passed through and beyond the applicator to apply the tubular shroud to the harness. The applicator is then returned for re-use. The invention will now be described further, by way of example, with reference to the accompanying drawings, in which : Fig. 1 is a perspective view of a wiring harness shroud assembly in accordance with the present invention showing a shroud partially removed from a tubular applicator; Fig. 2 is a plan view showing application of the shroud of Fig. 1 to a wiring harness; Fig. 3 is a rectangular piece of stretchable cloth from which the shroud of Fig. 1 is preferably made; Fig. 4 is a perspective view of a tubular applicator forming a part of the wiring harness shroud assembly of Fig. 1 and used to apply the shroud as shown in Fig. 2; Fig. 5 shows a wiring harness shroud assembly ready for application of the shroud to a wiring harness; and, Fig. 6 is a perspective view on an expanded scale of the preferred shroud closure means or single thread chain stitch and tab means for removing the closure means after a shrouded or dressed wiring harness has been installed. While the present invention was conceived and is being utilised in the automotive industry for the manufacture of motor vehicles, it will be appreciated that it is generally applicable to the installation of a wiring harness into any product including a wiring harness which must extend through an opening in a structural member of the product. Accordingly, the invention is directed to a method and apparatus for dressing or enshrouding a wiring harness to restrain pigtails, takeouts, connectors, harness hold-downs and the like, which may be referred to herein as extensions, for installation of the wiring harness. Reference will now be made to the drawing figures wherein a wiring harness shroud assembly 100 in accordance with the present invention is shown in perspective in Figs. 1 and 5. In Fig. 5, tubular shroud means comprising a shroud 102 formed of stretchable material is fully expanded and supported upon tubular applicator means while the shroud 102 is shown as being partially removed from the applicator means in Fig. 1. As shown in Fig. 2, the tubular applicator means preferably comprises an applicator tube 104 of a first diameter which is sized to receive and stretch or expand the shroud 102 for application to a wiring harness 106. A collar 108 surrounds and is secured to the application end 104A of the tube 104, i.e. the end of the applicator tube 104 which is moved along the wiring harness 106 to peel the shroud 102 from the tube 104 and apply it to the harness 106. The wiring harness 106, which can be used for electrical circuits of a motor vehicle or for other applications, is preformed as a central trunk or bundle 106A of electrical conductors. Projecting from the bundle 106A at varying locations along its length are pigtails 106B, takeouts 106C, connectors 106D, harness hold-downs 106E and the like which are collectively referred to herein as extensions. The extensions serve to make connections from electrical circuits or equipment to or through the electrical conductors of the wiring harness 106 to associated electrical circuits or equipment or to hold the harness 106 in place. In the illustrated embodiment, the wiring harness 106 is terminated by a grommet 106F which serves to seal the opening through which the harness 106 is inserted. The tube 104 and collar 108 are preferably formed of a stiff cardboard material for a low cost structure yet one which can be repeatedly used for a substantial number of shroud applications; however, a variety of materials can be used. For example, the tube 104 and collar 108 can be constructed of plastic, fibre glass, or other appropriate material. The collar 108 serves as a convenient hand-hold for application of the shroud 102 and also defines the limits of the applicator tube 104 for initial installation of the shroud 102 to the tube 104 prior to application of the shroud 102 to the wiring harness 106. The shroud 102 is formed of a stretchable material such as a two-way stretch blend cloth including spandex, a rubber or rubberised material, material reinforced by elastic thread or the like. As shown in Fig. 3, an elongated generally rectangular piece of cloth 110 having two opposed short sides 112, 114 and two opposed long sides 116, 118 is used to form the shroud 102. The long sides 116, 118 of the piece of cloth 110 are joined to one another by closure means to define the tubular shroud 102. The closure means preferably comprises a single thread chain stitch 120 best shown in Figs. 1 and 6, and tab means for securing the chain stitch 120 at one end of the shroud 102. While removable closure means is shown as extending substantially the entire length of the shroud 102 in the illustrated embodiments, in some applications the shroud 102 may include removable closure means only along a portion of its length. The tab means is forcibly removed to open the shroud 102 by freeing or releasing the chain stitch 120. Typically, the chain stitch 120 will then unravel. In the presently preferred embodiment, the tab means comprises a polymeric shaft 122 having an integral tab 124 at one end and an integral terminating bar 126 at the other end (see Fig. 4). A removal tag 128 includes an aperture 130 through which the shaft 122 extends. The tag 128 can be formed of cardboard, polymeric, or other appropriate material as preferred for a given application. The tab means as illustrated is essentially the same as the ubiquitous price tags which are inserted through material of clothing or other items constructed of easily penetrable material such as cloth. For this application, the shaft 122 of the tab means is inserted through one of the last stitches 120A of the single thread chain stitch 120 where it helps to perform the closure operation for the shroud 102 by stabilising the chain stitch 120 and preventing its unravelling. Thus, the tab means serves to hold the chain stitch 120 together during installation of the shroud 102 to the applicator tube 104, application of the shroud 102 to the wiring harness 106 and installation of the wiring harness 106 through an opening (not shown) in a structural member of a product being manufactured. Once the wiring harness 106 has been dressed or enshrouded and installed, the shroud 102 is opened by grasping the tag 128 and forcibly removing the tab to open the shroud 102 by releasing the chain stitch 120. The opened shroud 102 is then removed and may be discarded or retained for re-use as desired. The use of the tubular applicator in the method of the present invention is best illustrated in Fig. 2 wherein the shroud 102 is being applied to the wiring harness 106 by moving the applicator tube 104 to the right as shown by the arrow 132 relative to the wiring harness 106 while the shroud 102 is slid off the applicator tube 104 onto the wiring harness 106. Of course, the shroud 102 can be applied by moving the applicator tube 104 and the wiring harness 106 relative to one another. Accordingly, the shroud 102 can be applied by pulling the wiring harness through the applicator tube 104 or by mutual movement of the two.

Claims: A wiring harness shroud comprising a tubular section (102) of stretchable material for enshrouding a wiring harness (106), open at at least one end and having releasable closure means (120) extending along at least part of its length, the tubular section comprising a generally rectangular piece (110) of the stretchable material having its two long sides (116, 118) joined to one another by a closure means, CHARACTERISED IN THAT said closure means comprises a single thread chain-stitch (120), the chain stitch being secured at one end of the tubular section by tab means (122,124) which is forcibly removable to release the chain stitch and thereby open the tubular section. A wiring harness shroud according to claim 1, wherein the stretchable material is cloth. A wiring harness shroud according to claim 2, wherein the cloth is a two-way stretch blend including spandex. A wiring harness shroud according to any preceding claim, wherein the tubular section is expanded and supported on a tubular applicator (104) positioned therein. A method for inserting a wiring harness (106) including loose extensions (106B-106E) projecting therealong through an opening of a structural member during a manufacturing operation to produce a product including the structural member, comprising the steps of enshrouding the harness by inserting it from one end into a tubular shroud member (102) to contain the extensions within the shroud member, passing the enshrouded harness through the opening, and then removing the tubular shroud member from the harness, characterised in that the harness is inserted into a tubular shroud member as claimed in any of claims 1 to 3 and the chain stitch (120) is released after the harness has passed through the opening to rapidly open the tubular shroud member. A method according to claim 5, wherein the tubular shroud member is expanded by positioning a tubular applicator (104) therein and the expanded shroud member is applied to the wiring harness (106) by advancing the applicator and the wiring harness relative to one another to transfer the tubular shroud member from the applicator to the wiring harness.

Inventors: BENNETT KELVIN J, DEMOTT MARK E, BENNETT, KELVIN J, DEMOTT, MARK E.
Applicants: FORD FRANCE, FORD MOTOR CO, FORD WERKE AG, FORD FRANCE S. A., FORD MOTOR COMPANY, FORD MOTOR COMPANY LIMITED, FORD-WERKE AKTIENGESELLSCHAFT
Application year: 1991
Main classification: H02G3
IPC codes: H02G3, B60R16, H01B13