GB2363915A

GB2363915A - Cable termination grommet

Info

Publication number: GB2363915A
Application number: GB0015241A
Authority: GB
Inventors: Peter Sahlstrom; Niclas Ostman; Erik Andersson; Stefan Hedlund
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 2000-06-21
Filing date: 2000-06-21
Publication date: 2002-01-09
Anticipated expiration: 2020-06-21
Also published as: GB2363915B; GB0015241D0

Abstract

A cable 1 has an insulating covering sleeve 6 and two conductive cores 2,3 which are each provided with an insulating sheath 4,5. The cable 1 terminates at a moulded grommet 7 so that the fully insulated cable 1 emerges at one side of the grommet 7 and the uninsulated exposed cores 2,3 emerge from the other side. Within the grommet 7 the cores 2,3 are held so that when they emerge they are separated from each other by a greater distance than when the entered as the covered cable 1. A groove 8 can be provided in the grommet 7 to engage with a rib 16 of a housing 10 for a printed circuit board (PCB) 11 carrying electric components 12. The cores 2,3 can engage with contact pads 13,14 on the PCB 11. Once assembled the housing 10 can be filled with epoxy resin.

Description

2363915 PATENTS ACT 1977 P 14387 GB-NF/jsd DESCRIPTION OF INVENTION

"IMPROVEMENTS IN OR RELATING TO A CABLE TERMINATION" THE PRESENT INVENTION relates to a cable termination.

It is often necessary to secure an electrical connection between one or more cores of a wire or cable, and electronic circuitry within a case or housing.

Many electrical connector arrangements have been proposed for use in such circumstances, but most are relatively complex or, alternatively, require the cores of wires or cables to be secured using screws or the like.

The present invention seeks to provide an improved cable termination.

According to this invention there is provided an electrical cable termination, the termination being provided on a cable having at least two cores, the cable having insulation provided on the exterior of each core, and a further outer insulating sleeve, the termination comprising a grommet moulded on to an end part of the cable and being located between a region in which the insulating sleeve of the cable is present, and a region in which the insulating sleeve is absent, the grommet having the cable with the insulating sleeve 2 emerging from one side thereof, and having the conducting cores emerging from the other side thereof without the insulating sleeve with the cores in predetermined positions relative to the grommet and relative to each other, with the relative distance between the cores being greater than the distance between the cores within the insulating sleeve, the terminal part of each conducting core being un-insulated.

Preferably the grommet is provided with at least one groove in the outer surface thereof adapted to receive a rib.

The invention also relates to a combination of the cable termination as described above, and a housing containing electronic circuitry, the grommet being mounted at a predetermined position on the housing, the electric circuitry presenting a respective contact pad in contact with each of the conductive cores.

Preferably the grommet is provided with at least one groove in the outer surface thereof and the housing defines a passage to receive the grommet, the passage having an inwardly directed rib which is received within the groove formed in the grommet to position the grommet in a predetermined position.

Advantageously each conductive core is soldered to the contact pad that it is in contact with.

Conveniently the grommet substantially seals the housing.

Preferably the housing is filled with an epoxy resin.

3 In a preferred embodiment the housing contains a proximity switch to be responsive to a buckle of a vehicle seat-belt.

According to a further aspect of this invention there is provided a method of assembling an electrical connector comprising the steps of taking a cable having a cable termination to the type described above, and locating the grommet in a passage in a housing that contains electronic circuitry having two or more contact pads and thus locating each conducting core adjacent a respective contact pad.

Preferably the method includes the subsequent step of soldering each core to the respective adjacent contact pad.

Advantageously the method includes the further step of filling the housing with an epoxy resin.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIGURE 1 is a diagrammatic top view, with parts shown in phantom, of a cable termination in accordance with the invention, FIGURE 2 is a side view of the cable termination of Figure 1, and FIGURE 3 is a schematic view illustrating the cable termination in conjunction with electronic circuitry within a housing.

4 Referring initially to Figure 1 of the accompanying drawings, an cable termination is illustrated which is provided at the end of a cable 1 The cable 1 comprises two metallic cores 2, 3, each of which is provided with a respective insulating sheath 4, 5, the insulating cores being contained within an outer covering or sleeve 6 The sleeve 6 may simply surround the insulated inner cores, or the insulated inner cores may be embedded in and separated by the sleeve Such a cable is of conventional construction.

As shown in Figure 1, the outer sheath or sleeve has been cut back by a predetermined length, and part of the insulating sheaths 4, 5 on each of the inner cores 2, 3, have also been cut-away by a lesser length so that the end regions of the cores 2 and 3 are exposed.

A grommet 7 resilient of insulating material, such as a resilient polymer,

has been moulded on to the cable, with the grommet spanning a region of the cable between the part of the cable having the sheath 6 and the part of the cable where the exposed cores 2, 3 are present The grommet 7 defines a peripheral groove 8 which is provided on three sides of the grommet The groove lies in a plane perpendicular to the axis of the cable 1.

It can be seen, therefore, that the fully insulated cable 6 with the sleeve 6 enters the grommet at one side of the grommet, and two spaced-apart cores 2, 3, without the sleeve 6 emerge from the other side of the grommet As the grommet is moulded the cores 2, 3 that emerge from the grommet are held in predetermined positions The cores 2, 3 that emerge from the grommet are held apart by a distance that is greater than the distance between the cores when they are within the sleeve 6 The terminal parts of the cores 2, 3 that emerge from the grommet are un-insulated.

In the illustrated embodiment of the invention, the cores 2, 3, may be integral cores, or may comprise multi-cores which have been solder-dipped so that the protruding un-insulated terminal parts of the cores 2, 3, are substantially rigid.

It is to be appreciated that the peripheral groove 8 provided in the grommet 7 is dimensioned to receive an inwardly directed web forming part of a housing so that the grommet may be secured at a predetermined position within the housing The predetermined position is such that the extending cores 2,3, which project from the grommet are brought into contact with appropriate contact pads of circuitry with which electrical contact is to be established.

Referring now to Figure 3 of the accompanying drawings, a housing 10 is provided which is shown as being of a complex shape, although any shape of housing could be utilised with the invention Contained within the housing 10 is a printed circuit board 11 carrying electronic components 12 The printed circuit board also carries two contact pads 13, 14.

A passage 15 formed in the housing leads from the region of the printed circuit board 11 provided with the contact pads 13, 14 to the exterior of the housing, and this passage is provided with an inwardly directed web 16 dimensioned to be received within the groove 8 formed in the grommet 7.

The grommet 7 may thus be inserted into the passage 15 with the groove 8 receiving the web 16, so that the grommet 7 has a predetermined position The protruding cores 2, 3 of the cable are then automatically brought into alignment with, and into contact with the contact pads 13, 14 provided on the printed circuit board 11 within the housing.

The cores 2, 3 may then be soldered (or crimped or screwed) to the contact pads 13, 14 Because the cores 2, 3 are in alignment with the contact pads 13, 14, an automatic soldering (or crimping or screwing) process may be used.

It is to be understood that in utilising an electrical connector in accordance with the invention, it is possible to utilise straightforward manufacturing techniques to physically and electrically connect the cable 1 to a housing containing electronic circuitry.

In the illustrated embodiment the grommet 7, when inserted into the passage 15, essentially seals the housing 10 which contains the printed circuit board 11 Thus the grommet, together with upstanding side walls formed in the housing, forms a sealed chamber which contains the printed circuit board 11.

This chamber may be filled with an epoxy resin material which will serve to retain all of the components in a fixed position within the housing.

The housing 10 illustrated in Figure 3, is a housing formed of a plastics material which is to form part of a buckle for receiving a tongue provided on a safety-belt in a motor vehicle The housing 10 contains a proximity switch, in the form of a haul sensor 17, which is adapted to respond to the presence of the tongue provided on the safety-belt A magnet 18 is provided located adjacent the haul sensor 17 The electronic components 12 mounted on the printed circuit board are provided to process signals from the haul sensor.

In the described embodiment the grommet is of a resilient nature, and the resilient properties of the grommet are such as to facilitate insertion of the grommet 7 into the passage 15 within the housing, and also to ensure that the 7 grommet does form a seal within the passage 15 to prevent any epoxy resin leaking out of the housing after the housing has been filled with the epoxy resin and before the epoxy resin has set It is to be appreciate that whilst, in Figure 3, the housing has been illustrated in an "open-topped" condition, the housing may be provided with a lid or closure which is mounted on the housing as a final manufacturing step.

Whist the invention has been described with reference to an example in which a two-core cable has been utilised, it is to be appreciated that the invention may be equally applicable to a cable having three or more cores.

In the present specification "comprise" means "includes or consists of' and "comprising" means "including or consisting of'.

The features disclosed in the foregoing description, or the following

Claims

Claims, or the accompanying drawings, expressed in their specific forms or in tenms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof. 8 CLAIMS:

1 An electrical cable termination, the termination being provided on a cable having at least two cores, the cable having insulation provided on the exterior of each core, and a further outer insulating sleeve, the termination comprising a grommet moulded on to an end part of the cable and being located between a region in which the insulating sleeve of the cable is present, and a region in which the insulating sleeve is absent, the grommet having the cable with the insulating sleeve emerging from one side thereof, and having the conducting cores emerging from the other side thereof without the insulating sleeve with the cores in predetermined positions relative to the grommet and relative to each other, with the relative distance between the cores being greater than the distance between the cores within the insulating sleeve, the terminal part of each conducting core being un-insulated.

2 A cable termination according to Claim 1 wherein the grommet is provided with at least one groove in the outer surface thereof adapted to receive a rib.

3 A combination of a cable termination according to Claim 1, and a housing containing electronic circuitry, the grommet being mounted at a predetermined position on the housing, the electric circuitry presenting a respective contact pad in contact with each of the conductive cores.

4 A combination according to Claim 3 wherein the grommet is provided with at least one groove in the outer surface thereof, and wherein the housing defines a passage to receive the grommet, the passage having an inwardly 9 directed rib which is received within the groove formed in the grommet to position the grommet in a predetermined position.

A combination according to Claim 3 or 4 wherein each conductive core is soldered to the contact pad that it is in contact with.

6 A combination according to any one of Claims 3 to 6 wherein the grommet substantially seals the housing.

7 A combination according to Claim 6 wherein the housing is filled with an epoxy resin.

8 A combination according to any one of Claims 3 to 7 wherein the housing contains a proximity switch to be responsive to a buckle of a vehicle seat-belt.

9 A method of assembling an electrical connection comprising the steps of taking a cable having a cable termination according to Claim 1 or 2, locating the grommet in a passage in a housing that contains electronic circuitry having two or more contact pads and thus locating each conducting core adjacent a respective contact pad.

A method according to Claim 9 including the subsequent step of soldering each core to the respective adjacent contact pad.

11 A method according to Claim 9 or 10 including the further step of filling the housing with an epoxy resin.

12 An electrical cable termination substantially as herein described with reference to and as shown in Figures 1 and 2 of the accompanying drawings.

13 An electrical cable termination in combination with a housing containing electronic circuitry substantially as herein described with reference to and as shown in Figures 1 to 3 of the accompanying drawings.

14 A method of assembling an electrical connection substantially as herein described with reference to the accompanying drawings.

Any novel feature or combination of features disclosed herein.