GB2232014A

GB2232014A - Electrical cable joint assembly

Info

Publication number: GB2232014A
Application number: GB9001262A
Authority: GB
Inventors: Reginald John Serpell
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-01-19
Filing date: 1990-01-19
Publication date: 1990-11-28
Also published as: GB9001262D0; GB8901191D0

Abstract

A method of manufacturing an electrical cable joint assembly comprises disposing a body 11 of electrically insulative material within body housing shells 33a, 33b, the body 11 enclosing electrical connections between cores of multi-core cables 13, 15. Shells 33a, 33b, the body 11 and the cables 13, 15 are then placed within the cavity 44 of injection moulding apparatus 41 (Figure 10), where mould material is injected into the apparatus so as to encapsulate the body 11 and parts of the cables 13, 15 within the shells 33a, 33b. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO ELECTRICAL CABLE ASSEMBLIES BACKGROUND TO THE INVENTION This invention relates to electrical cable assemblies and to components thereof.

The invention is particularly concerned with "T"-joint electrical cable assemblies.

SUMMARIES OF THE INVENTION According to one aspect of the present invention, a method of manufacturing an electrical cable assembly comprises disposing a body of electrically insulative material within body housing shells, the body electrically connecting first and second multi-core cables, placing the shells, the body and the cables within the cavity of injection moulding apparatus, and injecting mould material into the cavity of the apparatus so as to encapsulate at least the body.

Preferably, the exteriors of the shells are encapsulated as well as the interiors thereof.

According to another aspect of the present invention, an electrical cable assembly comprises a body of electrically insulative material interconnecting first and second multi-core cables, and a mass of material encapsulating the said body of electrically insulative material.

The body of electrically insulative material is preferably formed with a plurality of channels extending across a flat surface of the body and a plurality of passages extending between the said channels and a second surface of the body, the second surface being disposed opposite the first surface.

The invention also comprises the said body of electrically insulative material per se.

The invention further comprises an electric cable harness which has a multiplicity of cable assemblies as herein set forth, and still further comprises a kit formed by the said body of electrically insulative material and a pair of housing shells, which together with the body may be used to construct a cable assembly.

BRIEF DESCRIPTION OF THE DRAWINGS The various aspects of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein : Figure 1 illustrates a conventional method of forming a "T"-joint electrical cable assembly, Figures 2 to 5 are front, rear, top and bottom views, respectively, of a body of electrically insulative material forming part of the "T"-joint assembly of Figures 2 and 3, Figure 6 is a side view in cross-section through the body of Figures 2 to 5, Figure 7 is a rear view of the body, with a cable connected thereto, Figure 8 is a front view of the body, with the cables to be jointed in place, Figure 9 is an exploded view in perspective of the "T"-joint assembly, and Figure 10 is a side view in section, of the assembly disposed within the cavity of an injection moulding apparatus.

DETAILED DESCRIPTION OF CONVENTIONAL MANUFACTURE It is common practice during, for example, the construction of new buildings, to manufacture electrical cable harnesses to a prepared specification.

With reference to Figure 1, the procedure briefly entails: preparing, in situ, at predetermined positions along a cable run, "T"-joints by soldering at 2, connected bared conductor mid (3) and end (4) portions of multi-core cables 5 and 6, as illustrated in the figure, fitting a pair of cooperating housing shells (not shown) around the "T"-joints so formed, the shells being temporarily held in juxtaposition by winding a tape of plastics material around the shells, and then transporting the harness in the thus incomplete state to an injection moulding apparatus. Here, thermoplastic material is injected into the housing shells under heat and a pressure of perhaps 400 psi. The housing shells are held in position, against the effects of such pressure, by contact between the housing shells and adjacent walls of the cavity within which the thermoplastic injection process is conducted.The completed harness is subsequently returned to the building for installation therein during building construction.

The housing shells are of a material compatible with the investment of thermoplastic material. The temporary tape binding the housing shells together is eliminated under the heat and pressure of the process, during which the thermoplastic material is injected so as to conform to the housing interior configuration, bonding between the housing shells and the investment being achieved by the process.

The known process described above is not well suited to the economic fabrication of electric wiring harnesses.

The production of solder or other joints between cables at the "T"-joints is not always well controlled, and, by virtue of the configuration of the housing shells in relation to the cavity of the injection moulding apparatus, there is a tendency for distortion under pressure of the composite housing formed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT With particular reference to Figures 2 to 8, in accordance with the present invention, each "T"-joint electrical cable assembly 1 (Figure 8) of a cable harness 10 comprises a body 11 of electrically insulative material, a first multi-core cable 13, a second multi-core cable 15 and an investment (not shown) comprising a mass of thermoplastic material which encapsulates the body 11 and segments of the cores of the cable means 13, 15 leading to the "T"-joint therebetween.

The body 11, which is of a heat resistant plastic material, (so as to resist the heat of soldering), is in the form of a block having substantially parallel front (or first) and rear (or second) surfaces 17a, 17b respectively. The front of the block 11 is formed with three surficial channels 19a, 19b. 19c, respectively, extending in a common plane thereacross, substantially parallel to the front surface 17a. Three passages 21a, 21b. 21c respectively, extend between the channels 19a, 19b, 19c and the rear surface 17b of the block 11. The block is preferably of A.B.S. material. (See below).

More particularly, the passages 21a, 21b. 21c respectively communicate between the surficial channels 19a, 19b, 19c respectively, and a second plurality of surficial channels 23a, 23b, 23c respectively, which extend in a common plane substantially parallel to the rear surface 17b and, hence to the front surface 17a and a common plane containing the surficial channels 19a, 19b, 19c. The surficial channels 19a, 19b, 19c are substantially parallel to one another. The surficial channels 23a, 23b, 23c, on the other hand, are unitary and form a cavity serving as a manifold 25 (Figures 3 and 7) fanning out from a manifold entrance portion 27 in directions respectively intercepting the several said passages 21a, 21b, 21c , and thereby establishing communication between the channels 19a etc. and 23a etc.

The channels 23a, 23b, 23c are individual, but are are notionally integrated into the manifold 25. The channels 23a etc. are of different lengths as determined by the locations in the front surface of the surficial channels 19a, 19b, 19c, to which communication is established by way of the passages 21a, 21b, 21c respectively.

Segments 29a of the cores of one cable 31a of the first multi-core cable 13 extend, respectively, along the three channels 19a, 19b, 19c, from one direction.

Segments 29b of the cores of a second cable 31b of the first multi-core cable 13 extend, respectively, along the three channels 19a, 19b, 19c from the other direction.

Segments 29c of the cores of a third cable 31c, being a second multi-core cable 15, extend, respectively, along the three channels 23a, 23b, 23c.

Bared conductor ends of the core segments 29c extend through the passages 21a, 21b, 21c respectively, to join with bared conductor ends of the segments 29a, 29b of the two cables constituting the first multi-core cable 13.

The block 11 serves, inter alia, as a jig facilitating the soldering together of the bared conductor ends, thereby forming a "T"-joint electrically connecting the cables 13, 15, which "T"-joint is stably supported by the block 11.

The block 11 is disposed within a composite housing 32 comprising a pair of cooperating body housing shells 33a, 33b. The cables 31a, 31b, being the first multi-core cable 13, extend, in the completed composite housing, through first and second entrance portions 35a, 35b respectively, and the cable 31c extends through a third entrance portion 35c of the composite housing, the longitudinal direction of the said third entrance portion being perpendicular to that of the entrance portions 35a, 35b.

Portions of the housing shells 33a, 33b, which, in the complete composite housing, cooperate to define the entrance portions 35a, 35b. 35c, each have three internally projecting rib portions as 37a, 37b, 37c respectively, so disposed as in the complete housing to extend circumferentially aligned with corresponding rib portions of the entrance portions of the other halfhousing.

The housing shells 33a, 33b are formed with external, integral pressure pads 39. Apertures (not depicted) extend through the housing shells to allow ingress of thermoplastic material during injection moulding.

The housing shells 33a, 33b are of the high impact polystyrene Acrylonitrile-Butadiene-Styrene (A.B.S.).

After conductor connection soldering, indicated by solder joints 30a, 30b, 30c (Figure 9), with several "T"joint assemblies 1 made at intervals along the harness 10 and with the housing shells 33a, 33b held in place by cooperating moulded-in pins (not shown) carried by shells 33a which are located by tight-fitting holes 49 formed in shells 33b, the harness is transported to an injection moulding apparatus 41 (Figure 10). The apparatus 41 comprises cooperating mould halves 42a 42b with an injection material entry passage 43 in mould half 42a.

At the apparatus 41, an assembly 10 is introduced into the chamber of cavity 44 of the apparatus. The housing shells 33a, 33b are forced together within the cavity 44, contact between the pressure pads 39 of the half shells 33a, 33b (not shown in Figure 10), and the surrounding wall-of the cavity 44, restricting any tendency for the housing formed by the shells to distort when injection takes place.Under the clamping pressure created by the mould halves 42a, 42bthe rib portions 37a, 37b, 37c bite into the sheaths of the cables within the entrance portions of the housing formed by the shells 33a, 33b so as to form both a clamp and a seal. li Molten A.B.S. material is then injected through the passage 43 formed in the mould half 42a and into the housing shells, as indicated by arrow 45, so as to encapsulate the block 11 and associated parts of the cables within the shells. Outward flow of the A.B.S.

along the cables is restricted by the presence of the dams formed by the cooperating rib portions 37a etc.

The injected A.B.S. material entering the mould cavity 44 also covers the exteriors of the housing shells 33a, 33b to a thickness substantially that of the pressure pads 39, whereby the outer extremities of the pads are substantially flush with the A.B.S. material covering the shells. Thus encapsulation takes place both outside and inside the housing shells 33a, 33b.

The molten A.B.S. may be forced into the mould cavity 44 at a pressure of perhaps 400 psi and at a temperature such that firm bonding of the matrix of molten plastic, the body 11, cables connected thereto and the shells 33a, 33b occurs.

Whilst in the described embodiment the composite housings within which the "T"-joint electrical cable assemblies are located constitute parts of the finished harness, this need not be so. Instead, a mould formed of a multiplicity of cooperable mould parts could be employed, the mould parts being subsequently separable from the investment of encapsulating A.B.S. material.

Thermoplastics material other than A.B.S. may be employed.

For example, NYLON 66".

Claims

1. A method of manufacturing an electrical cable assembly, comprising disposing a body of electrically insulative material within body housing shells, the body electrically connecting first and second multi-core cables, placing the shells, the body and the cables within the cavity of injection moulding apparatus, and injecting mould material into the cavity of the apparatus so as to encapsulate at least the body.

2. The method claimed in Claim 1, wherein the exteriors of the shells are encapsulated as well as the interiors thereof.

3 The method claimed in Claim 1 or 2, wherein the body comprises electrically insulative material, with a plurality of channels extending across a first surface of the body and a plurality of passages extending between the channels and a second surface of the body, the second surface being disposed opposite the first surface.

4. The method claimed in Claim 3, wherein a plurality of channels are formed in said second surface of the body.

5. The method of Claim 4, wherein the first-mentioned channels are disposed substantially parallel to each other and the last-mentioned channels are unitary.

6. An electrical cable assembly, manufactured according to the method of any one of Claims 1 to 5.

7. An electrical cable assembly, comprising a body of electrically insulative material electrically interconnecting first and second multi-core cables, and a mass of material encapsulating the said body of electrically insulative material.

8. An assembly as claimed in Claim 7, wherein the body of electrically insulative material is formed with a plurality of channels extending across a first surface of the body and a plurality of passages extending between the channels and a second surface of the body, the second surface being disposed opposite the first surface.

9. An assembly as. claimed in Claim 8, wherein a plurality of channels are formed in said second surface of the body.

10. An assembly as claimed in Claim 9, wherein the firstmentioned channels are disposed substantially parallel to each other and the last-mentioned channels are unitary.

11. An assembly as claimed in any one of Claims 8, 9 or 10, wherein the first-mentioned channels are disposed substantially parallel to one another, the said passages communicate with the said first-mentioned channels at different distances therealong, and the last-mentioned channels form a cavity in the said second surface, being a cavity in the form of a manifold from which the several channels fan out from a manifold entrance portion in directions respectively intercepting the said passages, thereby establishing communication between the first and last mentioned channels.

12. An electrical harness comprising a plurality of assemblies, each as claimed in any one of Claims 7 to 11.

13. A method of manufacturing an electrical cable assembly, substantially as hereinbefore described, with reference to Figures 2 to 10 of the accompanying drawings.

14. An electrical cable assembly, substantially has hereinbefore described, with reference to Figures 2 to 10 of the accompanying drawings.

15. The body of electrically insulative material, per se, of any one of Claims 7 to 11.