GB2076599A - Electrical Connector With Indexing Formations - Google Patents

Abstract

A connector assembly for a capacitive fuel-gauging probe 22 comprises sockets 2, 3, 4, mounted on the probe 22, and plugs 10 (only one shown). Co-operating surfaces of the plugs 10 and sockets 2, 3, 4 have differing formations relative to one another so that only the correct plug can be inserted in the correct socket, the plug 10 being insettable only in sockets 2, 3 in the illustrated case. A contact element 30 of each plug 10 may have a projection 40 that locks with an aperture 41 in a socket contact element 23. A housing 11 is movable relative to the contact 30 and pulling the housing 11 outwards engages a slope 18 with contact portion 35 to move the projection 40 out of the aperture 41 (see Figure 4, not shown). <IMAGE>

Description

SPECIFICATION Electrical Connector Assemblies This invention relates to electrical connector assemblies, and more particularly to plug and socket assemblies.

In many applications, such as in capacitive fuel-gauging systems, it is necessary to make several connections to a piece of electrical apparatus or equipment (such as, for example, a fuel-gauging probe) with a number of different electrical cables. In order to ensure that the correct cable is connected to the correct element on the electrical equipment, the cables and equipment are provided with co-operating connector elements which can only be engaged with the correct element on the other part. This has been done in the past by means of the bayonet type of connector in which the contact element on one part is in the form of one or more axial pins within a cylindrical outer sleeve; the contact element on the other part being in the form of mating female sockets similarly provided within an outer sleeve.The outer sleeve on one part is provided with a number of radiallyprojecting pegs that engage with co-operating recesses on the inner surface of the other sleeve.

The two parts are iocked by pushing together and rotating so that that the strain on the cable acts on the pegs and will not pull the two parts away from one another.

The above connectors have the disadvantage that they are relatively expensive to make and that, because they require to be locked by relative rotation, they can be difficult to use in inaccessible locations.

It is an object of the present invention to provide a connector assembly that substantially overcomes the above-mentioned disadvantages.

According to one aspect of the present invention there is provided an electrical plug and socket connector assembly for a capacitive fluidgauging probe, the assembly including a socket member having a first elongate electrical contact element extending axially of the socket member, and a plug member having an outer housing containing a second contact element that is arranged to engage with the first contact element, wherein said assembly includes a plurality of socket members and a plurality of plug members, the housings of said plug and socket members being provided with a configuration of axially extending surface formations which differ from one another on at least some of the plug and socket members so as thereby to prevent a said plug member being inserted in one of said socket members.

In this way, it is ensured that the correct plug is inserted in the correct socket.

The first and second contact elements may have co-operating locking means, thend contact element being mounted for limited displacement along its housing, and the housing having an inwardly directed surface formation that is arranged to engage the said second contact element on movement of the housing away from its respective socket member such as to urge the locking means out of engagement with one another and thereby permit withdrawal of said plug member from said socket member.

By providing locking means that are actuated by axial displacement of the plug within the socket, the need to cause relative rotation of the plug and socket is obviated, thereby facilitating mating of the two parts.

A connector assembly for a capacitive fuel gauging probe will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 illustrates schematically a crosssectional view across the assembly from one end; Figure 2 is a view to an enlarges scale from the other end of a part of the assembly shown in Figure 1; and Figures 3 and 4 are cross-sectional elevations of the assembly illustrating how the parts of the assembly are separated from one another.

The connector assembly comprises a first part or socket unit 1 provided with a number of sockets 2 to 4 (only three of which are shown), and a plurality of plugs 10 (only one of which is shown) which locate within respective sockets of the first part to thereby form an an electrical connection with the socket unit.

The socket unit 1 is formed from an inner plastics block 20 and an outer plastics sleeve 21 which extends around the block 20 and the probe 22 of a capacitive fuel gauging system. The block 20 and the sleeve 21 are suitably shaped to define the sockets 2 to 4 between them, which may be continuous, as with the sockets 2 and 3, or separate, as with the socket 4. Each socket 2 to 4 includes a metal contact element in the form of an elongate tongue 23 mounted on a ledge 24 within the socket. Electrical connection of each tongue 23 is made by electrical leads 25 which in turn make connection with an outer tube of the probe 22, via a metal stud (not shown) that protrudes through the block 20, and the various other components of the probe.

Each plug 10 comprises a semi-rigid outer plastics housing 11 within which is located an electrical contact element 30. The housing 11 is of generally rectangular shape being provided on its outer surface with a downwardly-projecting rail 13 that extends along the length of the housing at one side. The housing 11 has a forward portion 14 of reduced internal height that is provided, on its outer surface, with two upwardly-projecting rails 1 5 and 1 6 that extend rearwardly about half way along the housing. The rails 1 5 and 16 are both located inset from the sides of the housing 11 by equal distances. The forward portion 14 of the housing 11 is connected with its rear portion 1 7 via an inclined surface 18 that slopes upwardly from the forward to the rear portions.The housing 11 is open at its front and rear ends to permit entry respectively of the tongue 23 and a cable 26 that is connected with the rear end of the contact element 30. The inner surface of the housing 11 is also provided with a centrally located rail 1 9 that projects downwardly from the roof of the housing and extends forwardly of the inclined surface 18 to within a short distance of the forward end of the housing.

The contact element 30 in the second part 10 is formed from a unitary strip of brass or other metal, and may be plated, such as, with gold, to improve the contact. The element 30 has a substantially flat forward base portion 31 that is provided with an axial slot 32 that keys with a projection 33 on the bottom of the housing 11 so as to permit limited displacement along the housing but to prevent removal of the element.

The element 30 is bent back on itself in a loop at its forward end to produce a centrally-positioned spring portion 34 that is bent upwards at its rear end producing an inclined ramp portion 35. The sides of the element 30 at its forward end are bent upwards and across to form substantially Ushape side portions 36 that extend closely around the walls of the housing. The side portions 36 are also formed with down turned lips 37 that extend along the sides of the centrally-located internal rail 19. The rear part of the element 30 is raised a short distance and is formed with forward and rearward lugs 38 and 39 that are crimped respectively about the conducting wires 27 and the insulation 28 of the cable 26 so as thereby to secure it firmly with the contact element. The cable 26 could also be soldered or welded to the contact element 30 as appropriate.

When the plugs 10 of the connector assembly are mated in the socket 2, 3 or 4, the tongue 23 of each socket projects within the plug between the upper surface of the spring portion 34 and the lips 37. The resilience of the spring portion 34 and the separation between the spring portion and the lips 37, are such that the tongue 23 is clamped firmly between the lips and the spring portion, in good electrical contact with the contact element 30. The upper surface of the spring portion 34 is provided with a projection 40 that engages with a co-operating aperture 41 in the tongue 23 so as to lock the tongue with the contact element 30. The width of the tongue 23 is such that its edges also contact both the side portions 36 which further improves the electrical connection and helps correctly iocate the tongue with the contact element.The tip 42 of the tongue 23 is tapered across its width and thickness so as to facilitate insertion in the plug 10.

The engagement of the projection 40 in the aperture 41 is sufficiently firm, by virtue of the resilience of the spring portion 34, to prevent the plug 10 being separated from the socket 2 when tension is exerted on the cable 26. The plug 10 can only be separated from the socket 2 by pulling rearwardly on its housing 11. This causes the housing 11 to move rearwardly with respect to the contact element 30, as shown in Figure 4.

The inclined surface 18 of the housing 11 provides an inwardly directed portion that contacts the inclined portion 35 of the contact element 30 thereby forcing the spring portion 34 downwards against its resilience. This enlarges the gap between the spring portion 34 and the lips 37 thereby unlocking the tongue 23 from the projection 40 and allowing the plug 10 to be pulled clear of the socket 2.

The outer surface of the forward part 14 of the housing 11 is especially shaped so that it can only be inserted within the suitably shaped socket 2 in the socket unit 1, thereby ensuring that connection of the cable 26 is made with the correct part of the probe 22. In the arrangement shown, the housing 11 can only be inserted in the left-hand socket 2, the rail 13 projecting in a channel 50 in the block 20, since the downwardly projecting rail 13 will prevent insertion in the right-hand socket 4, whilst the upwardly projecting rail 1 6 will prevent insertion in the central socket 3. The rails 13, 1 5 and 16 thereby act as axially-extending key members that can engage only with co-operating channels or keyways in the first part.The housing 11 of the plug 10, and the sockets 2, 3 and 4 of the first part 1 could be arranged so that each plug will only fit in a respective one of the sockets or so that a socket can receive different ones of the plugs. For example, the connector assembly might have a socket unit with six sockets, and six plugs.

Three of the sockets might be so shaped that they will each only receive a particular one of the six plugs. The other three sockets might be shaped so that they will receive any one of the other three plugs. These other three plugs need not necessarily be identically shaped but could differ one from the other so that they could be withdrawn from the socket and inserted in another connector assembly in a unique way. The sockets and plugs may be coloured or marked with coloured tags to make identification of corresponding sockets and plugs more easy.

The plug and socket connector assembly described above has an advantage of reqviring only a push-in fit without relative rotation to lock the two parts together, thereby making secure assembly more easy.

Claims (14)

Claims

1. Electrical plug and socket connector assembly for a capacitive fluid-gauging probe, the -assembly including a socket member having a first elongate electrical contact element extending axially of the socket member, and a plug member having an outer housing containing a second contact element that is arranged to engage with the first contact element, wherein said assembly includes a plurality of socket members and a plurality of plug members, the housings of said plug and socket members being provided with a configuration of axially extending surface formations which differ from one another on at least some of the plug and socket members so as thereby to prevent a said plug member being inserted in one of said socket members.

2. Electrical assembly according to Claim 1, wherein said axially extending surface formations are rails and channels.

3. Electrical assembly according to Claim 1 or 2, wherein said first and second contact elements have co-operating locking means, wherein said second contact element is mounted for limited displacement along its housing, and wherein said housing has an inwardly directed surface fbrmation that is arranged to engage said second contact element on movement of the housing away from the socket members such as to urge said locking means out of engagement with one another thereby to permit withdrawal of the plug member from the socket member.

2. Electrical assembly according to any one of the preceding claims, wherein said plug members and said socket members extend parallel to the length of the probe.

5. Electrical assembly according to any one of the preceding claims, wherein the housing of said socket members is formed in two parts.

6. Electrical assembly according to any one of the preceding claims, wherein the housing of the socket members includes an outer sleeve which is arranged to extend around the probe.

7. Electrical assembly according to any one of the preceding claims, wherein the housing of the socket members, and the forward end only of the housing of the plug members are formed with a configuration of axially extending surface formations.

8. Electrical assembly according to any one of the preceding claims, wherein displacement of said second contact element along the housing is limited by engagement of a projection on the housing with a slot in the contact element.

9. Electrical assembly according to any one of the preceding claims, wherein the second contact element is formed in a resilient loop.

1 0. Electrical assembly according to Claim 3 or any one of Claims 4 to 9 dependent on Claim 3, wherein said locking means is provided by a projection on one of said contact elements that engages with a recess in the other of said contact elements.

11. Electrical assembly according to Claim 3 or any one of Claims 4 to 10 dependent on Claim 3, wherein the inwardly directed surface formation is provided by an inclined surface on the inner surface of the housing of said plug member.

1 2. An electrical assembly substantially as hereinbefore described with reference to the accompanying drawings.

13. A capacitive fluid-gauging probe assembly including an electrical assembly according to any one of the preceding claims.

14. A capacitive fluid-gauging probe assembly substantially as hereinbefore described with reference to the accompanying drawings.