Electricity: conductors and insulators – Conduits – cables or conductors – Combined
Reexamination Certificate
1998-04-21
2002-03-19
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Conduits, cables or conductors
Combined
Reexamination Certificate
active
06359226
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to a device and method for protecting and sealing exposed wires, particularly wires which make up electrical harnesses used in automobile engines.
2. Brief Description of the Background Art
Dimensionally-recoverable tubing is commonly used to protect spliced wires within electrical harnesses in the automobile industry. One of the preferred splice configurations is a “stub splice”. In a stub splice, each wire to be spliced has its electrically insulative covering removed at one end, to expose bare electrically conductive wire, with all of the bare wires to be spliced arranged to run in the same direction. The exposed bare wires are essentially parallel to each other at one end of the configuration. The bare wires are then crimped, welded or soldered together to form a “nugget”. Subsequently, the nugget must be protected and sealed from the external environment. A preferred means for protecting the nugget and sealing out moisture and other contaminants is to encase the nugget in a dimensionally-recoverable tubing which has a sealant/adhesive coating interior to the tubing. Typically, heat is applied to cause the sealant/adhesive to flow, while simultaneously causing the tubing to heat-recover (shrink) about the nugget. The tubing shrinks around the end of the exposed wires and the adhesive/sealant flows within the tubing to cover the exposed wires. The adhesive/sealant also flows along the wires to contact and cover a portion of the unstripped, electrically insulative wire covering. This provides a seal over the entire length of the exposed wires up to and including the beginning of the insulative wire covering.
However, during installation, the adhesive/sealant used in combination with the dimensionally-recoverable tubing tends to act as a lubricant, causing the tubing to slide or back off of the inserted wires. Typically, the tubing does not completely slide off the wires, but this may happen on occasion. This phenomenon is known as “milk-off”. When milk-off results in a substantial back off of the tubing from the inserted wires, (for example, the tubing has backed off of the inserted wires by more than about one third of the recoverable tubing length), the stub splice may not be sealed properly, and moisture can reach the exposed wires, causing a short. Further, if the adhesive/sealant available for sealing becomes significantly reduced in quantity due to leakage from the closure end of the tubing or due to being left on wires which are no longer enclosed by the tubing as a result of milk off, there may be inadequate adhesive/sealant to protect the exposed portion of the wires enclosed by the tubing.
A short may also occur if a strand of wire which is part of the nugget is bent up and pokes through the wall of the heat-shrinkable tubing while it is being recovered (at this time the tubing is hot and softened).
As is readily apparent, an electrical short within the wiring harness of the engine compartment of an automobile or other motor vehicle is not only inconvenient when the vehicle stalls, but may be dangerous to the driver and passengers of the vehicle.
The prior art contains a number of devices which have been designed to provide protection of electrical wiring splices from the elements, and in particular from moisture penetration, which tends to be one of the worst problems. Some examples of these prior art devices are described below. U.S. Pat. No. 3,984,912, issued Oct. 12, 1976 to Johnston et al., discloses a method for splicing cable in which electrical wire conductors which project from two insulated cable end portions are received in tubular electrical connectors which have been electrostatically precoated with electrical insulating material. Each precoated connector end portion respectively abuts and is sealed in engagement with insulation on an associated cable end portion. The precoated connectors are crimped so that they grip the wire conductors to form a basic electrical splice. A tubular inner melt liner and a tubular outer sleeve of thermoplastic electrical insulating material surround the basic splice. Heat is applied to simultaneously melt the inner liner and shrink the outer sleeve to encapsulate the basic splice.
U.S. Pat. No. 4,528,419, issued Jul. 9, 1985 to Charlebois et al., discloses a method of forming an encapsulated splice region between two cable ends. After end portions of the core have been exposed beyond the jacket and sheath or shield, the conductors are splayed outwards and the cable end portions are brought close together. Splices are then formed between conductors of the two cables and the conductors are folded over either one cable jacket or the other to locate each splice upon and supported by the jacket.
Each splice is individually covered with sealing material, and end regions of the cables are encapsulated so as to encapsulate the splices and to seal them so that they are fluid-tight. Heat is provided during the encapsulation of the splices in order to soften the sealing material so that it will completely surround each splice.
U.S. Pat. No. 4,849,580, issued Jul. 18, 1989 to Reuter et al., discloses a closure/sealant combination for use in providing an “environmental seal” around a wire junction or splice. The preferred embodiment of the closure has a unitary construction comprising an outer, openable shell having an internal biasing mechanism. Viscous sealant material is positioned within the closure such that the biasing mechanism forces sealant material around a junction to be sealed and, in particular, between adjacent wires in such junctions.
U.S. Pat. No. 4,863,535, issued Sep. 5, 1989 to More, discloses a method and arrangement for generating an environmental seal around a connection such as an electrical junction. The arrangement comprises a pad arrangement which is in association with a substrate and a sealant pad. The sealant pad comprises a highly viscous sealant which, under pressure, can be forced into areas between adjacent wires to provide effective moisture seals. According to a preferred method of the invention, a substrate having sealant on it is folded around a junction to be sealed, such that the substrate retains the sealant against the electrical junction. Pressure is applied to the enclosed sealant pad, generating hydraulic forces in such a manner as to direct the sealant against the electrical junction.
U.S. Pat. No. 4,963,700, issued Oct. 16, 1990, to Olsen et al., discloses a closure for providing an environmental seal about a wire junction. The closure comprises a closable shell defining, when closed, an internal wire junction receiving chamber having first and second opposite open ends for receiving wires. The shell comprises first and second shell sections, and an interference fit locking arrangement is oriented between the shell sections. The shell sections may be unitary (ie., joined along a hinge line), or they may be independent of one another, but engageable in a nesting manner. The interference locking mechanism preferably comprises a plurality of elongate, continuous, interengageable ratchet teeth. In use, sealant material is positioned within the shell sections, and a junction to be sealed is placed within the shell.
U.S. Pat. No. 4,974,042, issued Nov. 20, 1990, to Seabourne et al., and assigned to the assignee of the present invention, discloses a blocking arrangement for suppressing fluid transmission in cables, particularly for use in harnesses for automotive applications. The arrangement comprises a generally flat blocking array that is formed from a fusible polymeric sealant (e.g., a hot-melt adhesive or a thermosetting adhesive). The blocking array has a number of passageways for receiving wires of the cable. The passageways extend from one end of the array to the other. The assembly includes a heat-shrinkable covering that can be positioned around the blocking array in its flat configuration and recovered about the array by application of heat. The sealant is capable of melting during recovery of the co
Biddell William
Chandler Daniel A.
Hansen Erling
Mayo III William H.
Reichard Dean A.
Tyco Electronics Corporation
LandOfFree
Device and method for protecting and sealing exposed wires does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device and method for protecting and sealing exposed wires, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device and method for protecting and sealing exposed wires will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2846750