GB1592243A

GB1592243A - Plug for a motor vehicle ignition system

Info

Publication number: GB1592243A
Application number: GB20450/78A
Authority: GB
Original assignee: KM Kabelmetal AG
Current assignee: KM Kabelmetal AG
Priority date: 1977-10-06
Filing date: 1978-05-18
Publication date: 1981-07-01
Also published as: FR2405567A1; NL7809067A; ES240178U; ES236748Y; DE2744949C3; IT1109417B; ES236748U; IT7850572A0; DE2744949B2; SE7810432L; ES240178Y; DE2744949A1

Description

(54) PLUG FOR A MOTOR VEHICLE IGNITION SYSTEM (71) We, KABEL- UND METALL WERKE GUTEHOFFNUNGSHUTTE AKTIENGESELLSCHAFT, a body corporate organised under the laws of Germany of 271, Vahrenwalder Strasse, Hannover, Germany, do hereby declare the invention for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a plug (i.e. an electrical connection plug) for a motor vehicle ignition system, of the type comprising a grippable body (as herein defined) composed of an insulating material surrounding one or more contact components, which body engages an end portion of a screened electrical lead, whose screen (or a conductive component connected thereto) passes out through the body, whereby contact may be made with it on the outside of the plug. By a "grippable body", we mean, in the present description and claims, any plug body portion whose configuration is such that it can be readily grasped in the hand.

Plugs of this type have been known for a long time in a wide variety of forms of construction. They and similar plugs engaging an end portion of an unscreened cable are employed to connect an ignition coil to an ignition distributor of a motor vehicle.

Plugs falling within the ambit of the invention thus comprise both ignition coil plugs and ignition distributor plugs. Scarcely any problems are encountered nowadays with the plugs for unscreened leads. In the case of screened leads, on the other hand, the satisfactory and simple contacting of the screen of the lead concerned still presents problems. The known solutions to these problems are all relatively complicated. For example, in one commercially available distributor plug, a check nut is provided on the grippable body, which nut is screwable on to a tubular projection on the housing of the ignition distributor. When this nut is screwed up, the screen, which is led directly out from the lead through the body, is anchored on the distributor housing by means of the said nut. This mode of contacting the screen, however, is not only complicated, but also entails a risk of damage to the screen. Moreover the lead is exposed at the point at which the screen is led out, unless it is sealed, at some expense, so as to ensure waterproofness.

It is an object of this invention to provide a plug, e.g. an ignition distributor plug, for a screened lead, which is of simple construction and is simple to instal, but nevertheless permits reliable contact to be made with the screen of its lead, and is itself waterproof, and also permits a waterproof engagement with a housing, e.g. an ignition distributor housing.

According to the present invention, we provide a plug for a motor vehicle ignition system, comprising a grippable body (as herein defined) composed of an insulating material surrounding one or more contact components, which body engages an end portion of a screened electrical lead, whose screen (or a conductive component connected thereto) passes out through the body, whereby contact may be made with it on the outside of the plug; wherein, around a middle region of the body, a metal ring is provided which is firmly embedded in the material of the body and which projects beyond the body all around its middle region, the screen of the lead within the body being connected conductively to the ring.

By virtue of the use of the abovementioned metal ring, which may be introduced as a mould insert into a mould employed for the production of the body by injection moulding, for example, a satisfactory and dimensionally accurate anchorage means is provided for the purpose of making contact with the screen of the lead. Because the screen itself is attached to the metal ring, moreover, it is possible for the full screening effect to extend even to the appliance into which the plug is plugged.

Insofar as the screen is accommodated within a watertight body and the ring is watertightly embedded in the material of the body, it is possible to arrange for the plug as a whole to be of waterproof construction. Furthermore, installation and extraction of the plug of the invention are normally extremely simple.

Two embodiments of the invention are shown in the accompanying drawings, in which: Figure I is a side view of a plug according to the invention, Figure 2 is a view in longitudinal section of the plug of Figure 1, and Figure 3 is a view in longitudinal section, on a somewhat smaller scale than Figures 1 and 2, showing a plug of a construction which is varied with respect to the case of Figures 1 and 2.

The Figures show at 1 a connection plug for a motor vehicle ignition system, which in principle may be either an ignition distributor plug or an ignition coil plug. This plug forms a termination for an electric lead 2 which has a screen around its conductors, so that a fully screened connecton is obtainable.

In the plug of Figures 1 and 2, a grippable body (as herein defined) 3 carries, around a middle region thereof, a metal ring 4, having been securely moulded to this ring.

However, the ring 4 projects beyond the body 3 all around its middle region. In the interior of the body 3, the screen 5 of the lead 2 is connected conductively to the ring 4; for this purpose use may be made of (e.g.) a pinch connector 6, as shown in Figure 2.

In the embodiment of Figures 1 and 2, the body 3 is composed entirely of only one material; this can be a rigid heat-resistant insulating material, e.g. a polyamide resin, which may be a glass-fibre-reinforced polyamide resin. The lead 2 has two conductors, but only one conductor 7 appears in Figure 2. This conductor 7 is attached to a contact component 8, which is also accommodated within the body 3. The second conductor and the associated second contact component lie just behind the conductor 7 and contact component 8.

To produce the plug of Figures 1 and 2, the following procedure may for example be adopted. After the preparation of the end portion of the lead 2, the screen 5 is connected to the ring 4. Next the two conductors are connected to the appropriate contact components, and the lead end assembly thus prepared is inserted into an injection mould. In this mould the body 3 is injection-moulded round the lead end and the contact components, in a shape as shown in Figures 1 and 2. In this process the internal metal components and the connections at the end of the lead are surrounded securely and watertightly by the material of the body 3.

The plug shown in Figures 1 and 2 is suitable more particularly for use as an ignition distributor plug. This plug is not resilient, because a rigid insulating material is used for the body 3. However, no resilience is necessary provided that one or more resilient seals of a rubbery material are present in the ignition distributor housing for which the plug is intended, the said seal(s) being compressed when, after introducing the plug into a socket therefor, the user tightens (e.g.) a cap nut or lock nut whereby the ring 4 is (e.g.) urged upwards against the housing. It is also possible to fit a metal housing over the body, and to employ (e.g.) a cap nut or a bayonet fastening only over the housing. This construction can be particularly significant if an unscreened section of the assembly would occur between the ring 4 and the undisturbed stretch of the screen, were that section not screened by the housing just mentioned.

The variant of the plug of Figures 1 and 2 which is shown, on a smaller scale, in Figure 3 is a plug which is suitable more particularly for use with an ignition coil. Here again the screen 5 of the lead is attached to a metal ring 4 which projects beyond the body of the plug all around its middle region. The lead 2 here has only one conductor 9, which is attached to a contact component 10. The body itself consists in this case of two distinct components 11 and 12 composed of insulating materials, the first component, 11, on the contact component side, being of a rigid heat-resistant material, and the second component, 12, on the lead side, being of a resilient material. For the first component, 11, a polyamide resin, e.g. a glass-fibre-reinforced polyamide resin, is suitable, as in the embodiment of Figures 1 and 2; the second component, 12, however, may comprise (e.g.) a polyurethane or silicone insulating material. The use of a component 12 of a resilient material makes possible a waterproof connection to the insulation of the lead 2.

To produce the embodiment of Figure 3, the following procedure may be adopted.

First the ring 4 together with the first tubular component 11 of the body, this component 11 having already been fabricated, is slid on to the end of the lead. The conductor 9 is next connected conductively to the contact component 10. Then the ring 4 and the first body component 11 are brought into the position shown in Figure 3, and the screen 5 is connected (e.g. welded or soldered) conductively to the ring 4. The lead end assembly thus prepared is inserted into an injection mould. In this mould the second component 12 of the body is injection-moulded so that all the cavities within the first body component 11 are filled, and also the connection between the screen 5 and ring 4 is surrounded by the insulation material in question.

In the embodiment of Figure 3, an encircling bead 13 composed of the resilient insulating material (i.e. that used to form the second body component) is present on that side of the ring 4 which is the nearer to the contact side, i.e. to the leading end of the plug. The provision of this bead 13 enables an effective seal to be made when the plug is installed. Here again it is possible to make use, for the purpose of anchoring the plug, of (e.g.) a cap nut which engages around the ring 4 and urges the latter against the housing of the ignition coil; the bead 13 can then act as a particularly effective seal element.

WHAT WE CLAIM IS: 1. Plug for a motor vehicle ignition system, comprising a grippable body (as herein defined) composed of an insulating material surrounding one or more contact components, which body engages an end portion of a screened electrical lead, whose screen (or a conductive component connected thereto) passes out through the body, whereby contact may be made with it on the outside of the plug; wherein, around a middle region of the body, a metal ring is provided which is firmly embedded in the material of the body and which projects beyond the body all around its middle region, the screen of the lead within the body being connected conductively to the ring.

2. Plug according to claim 1, wherein the body is composed entirely of a rigid heat-resistant insulating material which is in intimate contact with the ring and with the lead.

3. Plug according to claim 2, wherein the body is composed of a polyamide resin.

4. Plug according to claim 3, wherein the polyamide resin is a glass-fibrereinforced polyamide resin.

5. Plug according to claim 1, wherein the body comprises a first component, composed of a rigid heat-resistant insulating material, which affords a contactcomponent-accommodating portion of the body; and a second component, composed of a resilient insulating material, which affords a lead-accommodating portion of the body; the body also incorporating a structure composed of the resilient insulating material, taking the form of a bead encircling the first component of the body and disposed adjacent to the ring, on the side of the ring which is the nearer to the leading end of the plug.

6. Plug according to claim 5, wherein the rigid insulating material is a polyamide resin and the resilient insulating material comprises a polyurethane or silicone insulating material.

7. Plug according to claim 6, wherein the polyamide resin is a glass-fibrereinforced polyamide resin.

8. Plug according to claim 1, substantially as described with reference to Figures 1 and 2, or Figure 3, of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. brought into the position shown in Figure 3, and the screen 5 is connected (e.g. welded or soldered) conductively to the ring 4. The lead end assembly thus prepared is inserted into an injection mould. In this mould the second component 12 of the body is injection-moulded so that all the cavities within the first body component 11 are filled, and also the connection between the screen 5 and ring 4 is surrounded by the insulation material in question. In the embodiment of Figure 3, an encircling bead 13 composed of the resilient insulating material (i.e. that used to form the second body component) is present on that side of the ring 4 which is the nearer to the contact side, i.e. to the leading end of the plug. The provision of this bead 13 enables an effective seal to be made when the plug is installed. Here again it is possible to make use, for the purpose of anchoring the plug, of (e.g.) a cap nut which engages around the ring 4 and urges the latter against the housing of the ignition coil; the bead 13 can then act as a particularly effective seal element. WHAT WE CLAIM IS:

1. Plug for a motor vehicle ignition system, comprising a grippable body (as herein defined) composed of an insulating material surrounding one or more contact components, which body engages an end portion of a screened electrical lead, whose screen (or a conductive component connected thereto) passes out through the body, whereby contact may be made with it on the outside of the plug; wherein, around a middle region of the body, a metal ring is provided which is firmly embedded in the material of the body and which projects beyond the body all around its middle region, the screen of the lead within the body being connected conductively to the ring.