Electricity: conductors and insulators – Conduits – cables or conductors – Combined
Reexamination Certificate
1999-11-23
2001-05-29
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Conduits, cables or conductors
Combined
C174S08800C, C174S1130AS
Reexamination Certificate
active
06239374
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to methods for producing flexible cable harnesses such as cable trees for motor vehicles, and to the resulting harnesses.
Cable harnesses having a treelike structure, known as cable trees, are made of a bundle of several electric cables and are used for the electrical connection of components, consuming devices and assemblies. The electric cables which are parallel to each other are bundled together with predetermined departures of cables from the bundle and preferably are fixed in a bundle by wrapping tape or by an insulating cover. The cable harness must be flexible and should be capable of being wrapped so that it is packable and readily transportable and, for placement and assembly in a motor vehicle, it should also be capable of being bent 90°. With the increasing number of consuming and control devices in modem motor vehicles, the number, and in some cases the cross-section, of the cables to be connected in such a cable tree also increases and hence its flexibility decreases. Thus, the cable harness becomes increasingly rigid.
In order to prevent damage to the cables, complete enclosure of the cable harness is required. Complete but loose wrapping of the bundle, i.e., wrapping with low tensile force to assure adequate flexibility, can be obtained only by hand wrapping and leads to subjectively variable results with regard to wrapping thickness and strength. Wrapping machines, on the other hand, wrap with a high minimum tensile force, which leads to a very firmly wrapped and hence rigid cable harness.
In order to be able to wrap a cable harness mechanically and yet make it flexible, it has been sought to introduce into the cable harness, prior to wrapping, a blind cable in the form, for example, of a single cable of sizeable diameter or in the form of a wire having a non-adhesive coating, in particular a Teflon-coated wire, and, after mechanical wrapping of the harness, to withdraw the blind cable from the bundle, in order thereby to loosen the firmly and uniformly wrapped bundle of cables enclosed by the wrapping and increase the flexibility of the wrapped cable harness. This method has been found to have drawbacks. On the one hand, sticking of the blind cable to the wrapping tape or, with a blind cable having an anti-adhesion coating, sticking to adjacent cables, may occur which, in the latter case, may lead to damage of the cable insulation upon withdrawal of the blind cable and, on the other hand, makes withdrawal of the blind cable increasingly difficult with increasing length.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide a method for producing a flexible cable harness, and a resulting harness, which overcome disadvantages of the prior art.
Another object of the invention is to provide a method for producing a flexible cable harness in which the cable harness, after firm wrapping, maintains an adequate degree of flexibility.
These and other objects of the invention are attained by enclosing a bundle of cables together with a long cable-like body having an adjustable cross-section and, after the bundle has been enclosed, reducing the cross-section of the cable-like body. Introduction of a cable-like body with an adjustable cross-section into the bundle of cables enlarges the cross-section of the bundle to be enclosed by the initial cross-section of the cable-like body. The bundle of cables is then firmly enclosed mechanically in a conventional fashion, for example, by wrapping with wrapping tape. After wrapping has been completed and a rigid and not very flexible cable harness has been obtained, the cross-section of the cable-like body is reduced and the flexibility of the cable harness thereby increased. The wrapping process may be discontinued after only a portion of the bundle containing the cable-like body which is adjustable in its cross-section has been enclosed so that the cross-section of that portion of the bundle may be reduced as required for a particular application. In this case, if the cable-like member with an adjustable cross-section is an air-filled hose, for example, the cross-section of the wrapped portion of the bundle may be reduced by piercing or cutting the air hose, and then wrapping of the bundle can be continued. The diameter of the adjustable cable-like member and hence its share of the cross-section of the bundle of cables can be varied, as a result of which the flexibility of the cable harness can also be varied in a predetermined manner.
To this end, the cable-like member having adjustable cross-section may be made of an elastic material which is elastically expanded when it is introduced into the bundle and is relaxed or contracted after wrapping.
A suitable cable-like member having an adjustable cross-section may be, for example, an inflated hose of a thin-walled synthetic material or of thin-walled rubber, which is introduced into the bundle of cables in the inflated state and from which the filling gas, for example air, is released after enclosure of the bundle by wrapping, for example, by piercing the hose. In order to facilitate such piercing and make it suit a particular application, the hose may project from one end of the cable harness or, alternatively, it may be provided with a lateral tab. After release of the gas, the hose relaxes and contracts so that the fixed cross-section of the bundle of cables within the enclosure is reduced. As a result, the arrangement of the cables in the bundle becomes looser and the cable harness as a whole becomes more flexible even though the contracted hose remains in the cable harness. Damage to the cable insulation, which could occur upon withdrawal of a blind cable from the cable harness, is thereby avoided, and any disadvantageous sticking that could occur is not encountered.
Instead of an inflatable hose, an expanded long cable-like tube of a thermoplastic material may be placed in the bundle. In this case, the cable harness need only be heated briefly after enclosure of the bundle in order to shrink the tube and effect relaxation of the arrangement of bundle of cables and provide the desired increase in flexibility.
In addition, it is also possible to introduce a cable-like body of adjustable cross-section, not into the entire cable harness, but only into regions of the bundle which must be flexible based on assembly conditions, so that a cable harness having regions of unlike flexibility is produced.
REFERENCES:
patent: 5286923 (1994-02-01), Prudhon et al.
patent: 2459596 (1976-06-01), None
patent: 0 305 058 (1989-03-01), None
patent: 9203832 (1992-03-01), None
Baker Bott L.L.P.
Mayo, III William H
Reichard Dean A.
Volkswagen AG
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