GB2269485A

GB2269485A - Sealed electrical connector

Info

Publication number: GB2269485A
Application number: GB9215373A
Authority: GB
Inventors: Philip Kenneth Roderic Bateman; Alan Christopher Penfield
Original assignee: MK Electric Ltd
Current assignee: Novar ED&S Ltd
Priority date: 1992-07-20
Filing date: 1992-07-20
Publication date: 1994-02-09
Anticipated expiration: 2012-07-20
Also published as: GB2269485B; GB9215373D0; HK95897A

Abstract

An electrical connector assembly comprises a front plate (3) provided with electrical contacts (4), and a moveable lid (5) for covering the front plate (3), the front plate (3) and lid (5) together forming (a) an enclosure accommodating a counterpart (not shown) mated with the contacts (4) and (b) an opening (12, 13) communicating with the enclosure, the opening receiving an electrical wire or cable. Sealing means (II, 14, 15) seals between the lid (5) and the front plate (3) and seal the opening (12, 13) when the lid (5) is closed. The seal round the cable may be formed from a gel. <IMAGE>

Description

CONNECTOR ASSENBLY This invention relates to electrical connector assemblies, and more particularly to an electrical connector assembly adapted to be sealed against the ingress of moisture.

Electrical accessories of the plug and socket type, intended for household or light industrial use, are in general not environmentally sealed, and more especially are not usually moisture-proof. For outdoor applications, socket assemblies are commercially available, in which a hinged lid or cover is provided to prevent the ingress of moisture, but even with these it is necessary to lift the lid or cover in order to obtain access to the socket, and when a plug is inserted in the socket the lid or cover is prevented from returning to its rest position by the body of the plug and/or the cable attached thereto. Such electrical accessories are thus not environmentally sealed when in use.

There are, of course a variety of specially-designed waterproof electrical connectors which have been proposed for specific purposes, for example those in which the plug body and the socket housing cooperate to form a seal therebetween, or in which a sealing member on the plug is screwed into sealing contact with a screw-threaded boss on the socket housing, but such electrical connectors require special components, and such components are not readily inter-engagable and interchangeable with standard plugs and sockets.

In many applications, the lack of an environmental seal around the conventional plug and socket connection is clearly a disadvantage, and in some circumstances can be positively dangerous. We have now invented an electrical connector assembly wherein the front plate or shroud can be environmentally sealed when not in use, and in which, when a cable, wire, plug, or connection device is inserted therein, the electrical connection can also be environmentally sealed.

According to one aspect of the present invention, there is provided an electrical connector assembly comprising: - a front plate provided with electrical contacts, - a lid or cover movable between an open position allowing access to the front plate and a closed position in which the front plate is covered by the lid or cover, - the front plate and the lid or cover cooperating to form an enclosure adapted to accommodate an electrical connection device and an opening communicable with the enclosure, the opening being adapted to receive an electrical wire or cable, - sealing means adapted to form a seal between the lid or cover and the front plate and to seal the opening, when the lid or cover is in its closed position, such that the enclosure is environmentally sealed, - the arrangement being such that the enclosure is also environmentally sealed by the sealing means when the lid or cover is in its closed position and a wire or cable is positioned such that it passes through the opening.

The invention provides a simple yet effective means of environmentally sealing the front plate or shroud of an electrical connector assembly for example against the ingress of water. It is particularly applicable to the environmental protection of electrical plug and socket assemblies and will henceforth be more particularly described with reference thereto. It is to be understood, however, that the invention is not limited to such assemblies and may find application in electrical connection assemblies generally.

Preferably the socket assembly comprises a sealed housing, and in such preferred embodiments it has been found possible to achieve a protection against moisture ingress in conformance with the standards of IP55.

Either the front plate or the lid or cover, or both, may be recessed in order to provide the enclosure to accommodate the electrical connection device, and in the case of a plug and socket assembly, such that the entire plug body can be accommodated within the enclosure. Preferably the enclosure between the front plate and the lid or cover is shaped so as to receive one or more types of conventional 2-pin or 3-pin plug body therein, of the type used in, for example, 5 amp, 13 amp, or 15 amp circuits.

The front plate is provided with electrical contacts; that is to say, the electrical contacts may, for example, be situated behind the face of the front plate and accessible through holes in the front plate. The holes and electrical contacts may be shaped to receive the typical round pin or square pin of a two-pin or three-pin plug. Other designs are also possible, however, for example the contacts may be flat contacts on the face of the front plate, or there may be contact pins extending from the face which cooperate with female contacts on the plug, or the front plate may be provided with any other means of making electrical connections, for example screw contacts.

The lid or cover may be separate from the housing and or the front plate, but preferably the lid or cover is pivotally mounted and most preferably is hingedly connected to the front plate. Preferably the lid or cover is resiliently biased towards its closed position. The hinge is preferably arranged along the top edge of the lid or cover so that access to the front plate is obtained by lifting the lid or cover, for example against the action of a bias spring and or the weight of the lid or cover itself.

Preferably the lid or cover and the front plate have cooperating cut out portions which are in register when the lid or cover is in its closed position, defining an opening communicating to the interior of the enclosure, adapted to receive an electrical wire or cable attached to the plug.

Alternatively, the cut-out portion can be wholly within the front plate, or wholly within the lid or cover.

According to the invention the enclosure is environmentally sealed by the sealing means whether or not a plug is inserted into the socket. Although it may be possible to use a single sealing means, preferably there is provided a first sealing means, which forms a seal between the lid or cover and the front plate when the lid or cover is in its closed position, and a second sealing means, which seals the opening formed between the lid or cover and the front plate.

Preferably the first sealing means extends around or within the periphery of the lid or cover, or the front plate, or both, and may for example comprise one or more resilient sealing strips of polymeric material extending around or within the periphery of the lid or cover or the front plate. A raised rib or a channel shaped so as to cooperate with the one or more sealing strips may be provided to enhance the sealing effect.

The second sealing means may take a variety of forms as will be more particularly described herein. The second sealing means needs to seal the opening when the socket is empty, that is to say when there is no wire or cable positioned such that it passes through the opening, and also to seal around the wire or cable when it is present.

Preferably the second sealing means is resiliently deformable, in order to accommodate and to seal around the wire or cable. Examples of deformable sealing means which can be used include brushes, fluid-filled bags, elastomeric blades, elastomeric split bushes, hollow deformable moulded or extruded elastomeric shapes, and elastomeric clam shell constructions. Preferably, however, the second sealing means comprises a gel sealing member which, in the closed position, is held under compression within the opening.

The use of a gel under compression for sealing purposes is described in British Patent Specification number 2168363, and European Patents numbers 0190938, 0196219, 0189240, 0174165, 086110 and 0108518, the entire disclosures of which are incorporated herein by reference. It is possible to use only one gel sealing member, but preferably a gel sealing member is carried on each of the lid or cover and the front plate, such that when the lid or cover is moved to its closed position the two gel sealing members are compressed against each other and effectively seal the opening formed by the lid or cover and the front plate.

The gel sealing members may be formed in situ in the required positions on the lid or cover and the front plate, but preferably they are each carried on a support member upon which they are formed, or within which they are moulded, in order to give a good adherence to the support member. By an appropriate surface treatment, for example roughening, abrasion, or perforation of the support member the gel sealing members can be arranged to adhere more strongly to their respective support members than to each other, thus allowing them to be parted when the lid or cover is opened. The support member can, for example, be a cassette, capsule or trough within which the gel sealing member is contained.

The gel sealing members preferably present a flat surface to each other, but they may also be stepped, or otherwise contoured, as desired.

Gel sealing members for use in the present invention should be capable of adhering to a substrate, in this case the cable attached to the plug body, but should part cleanly therefrom when separated, leaving little or none of the gel on the cable insulation. When the lid or cover of the socket assembly is brought to its closed position with the plug and cable inserted, the gel sealing members in the opening can deform and flow around the cable to form a seal. When the lid or cover is opened and the cable is removed, the gel members will tend to return to their original shape in order to seal the opening once more.

With the preferred gel sealing members of the present invention this operation may be repeated many thousands of time without destroying the sealing effect.

The gel composition used for the manufacture of the gel sealing members used in the present invention is one which has an adhesive strength to the wire or cable insulation which is less than its adhesive strength to its associated support member and less than its cohesive strength.

The preferred gel sealing member or members for use in the present invention have cone penetration values of greater than 50, measured using the method of ASTM D217-68 as described in British Patent Specification number 2168363.

In addition, the gel members preferably have an ultimate elongation of at least 200%, measured using the method ASTM D638-80 as described in British Patent Specification number 2168383. Preferred gel members have a cone penetration value of 100 to 350 and an ultimate elongation of at least 500%.

Other preferred physical parameters, including tensile strength and elastic modulus, can be ascertained by reference to the above mentioned patent specifications.

Suitable gel sealing members may be made by gelling components which are commercially available for the preparation of polyurethane gels, in the presence of a suitable amount of an appropriate plasticiser, or a mineral or vegetable oil, or by curing reactive silicones together with non-reactive extender silicones.

The gel sealing member or members are preferably electrically insulating, i.e. have a resistivity of at least 109 ohm centimetres.

Where the second sealing means comprises a gel sealing member, it is important that the gel be kept under compression in order for it to provide the appropriate sealing properties. In some circumstances this may be achieved simply by the weight of the lid or cover, or by a bias spring associated with the hinged mounting of the lid or cover. Preferably, however, the socket assembly is provided with a latching or locking mechanism adapted to exert a compressive force between the lid or cover and the front plate so as to compress the gel sealing member or members. This may also have the effect of compressing the first sealing means so as to give a tight seal around or within the periphery of the lid or cover and the front plate.Any suitable lock or latch mechanism may be provided, and for example a simple detente on the lid or cover cooperating with a lip on the front plate and or housing may be perfectly adequate. Other more complicated locking systems may be required if a greater compressive force is necessary to achieve the desired sealing effect.

The present invention provides an electrical socket assembly which, in preferred embodiments, is capable of receiving any conventional two-pin or three pin plug and providing a sealed connection thereto.

Certain embodiments of electrical socket assemblies according to the invention will now be described by way of example with reference to and as illustrated in the accompanying Drawings in which: - Figure 1 shows a perspective view of a front plate of an electrical socket assembly according to the invention, showing the lid or cover in the open position; - Figure 2 is a perspective view of an electrical socket assembly using the front plate of figure 1 with the lid or cover in the closed position and with a plug and associated cable inserted therein; - Figure 3 shows the electrical socket assembly of figure 2 in side elevation with the position of the gel sealing members indicated by broken lines; - Figure 4 shows a gel cassette suitable for use in the embodiment of figures 1 to 3;; - Figure 5 shows a fragmentary view of the cable sealing means of a second embodiment of a socket assembly according to the invention, showing moulded gel sealing members; -Figures 6A, 6B and 6C show a further design of moulded gel sealing means for use in the electrical socket assembly of the invention, illustrating the application of the sealing means to different sizes and shapes of electrical cable; -Figures 7A and 7B show another embodiment for a sealing means for use in a socket assembly according to the invention which employs resiliently deformable brushes;; -Figure 8A and 8B show a further embodiment of a cable sealing means suitable for use in an electrical socket assembly according to the invention which employees fluid filed flexible bags, figure 8A being a perspective view, partly in section, and figure 8B illustrating the sealing of a cable; -Figure 9 shows a still further embodiment of a cable sealing means suitable for use in an electrical socket assembly according to the invention, in perspective view and partly in section and employing resiliently deformable blades; - Figure 10 shows an embodiment similar to that of figure 9 except that a double blade is used in place of one of the single blades of figure 9;; - Figure 11 shows yet a further embodiment of a cable sealing means suitable for use in the socket assembly of the present invention, which comprises a split elastomeric bush; - Figure 12 shows another embodiment of a cable sealing means which comprises a pair of hollow elastomeric extruded profiles; - Figure 13 shows yet another embodiment of a cable sealing means which employs a clam shell construction; and - Figure 14 shows an alternative latching arrangement to that shown in figure 1.

Referring now to figures 1 to 4, the socket assembly (1) comprises a front plate 2 and a housing 2a, the front plate (2) having a recessed front face or shroud (3) within which are situated holes (4) for the reception of the pins of an electrical plug. Beneath the holes (4) are electrical contacts and terminals for the connection of electrical wires (not shown). The assembly has a lid or cover (5) which pivots about a spring-biased hinge (6) located at the top edge of the front plate (2). The front plate and the lid or cover are moulded from a suitable polymeric material, for example, a polycarbonate.

Latching means, comprising plastic moulded lugs (7) on the lid or cover which cooperate with spring sockets (8) at the opposed side edges of the front plate (2), is provided so that the lid or cover applies a compressive force to the peripheral regions of the front plate when in its closed position.

Located around the edge of the recess (9) in the front plate is a groove (10) within which an appropriately configured elastomeric sealing strip (11) is placed, which cooperates with a rib moulded on the lid or cover (5) to form a close fit.

A cable outlet is provided by cut-out portions (12) and (13) in the lid or cover and front plate respectively, which portions are sealed by rectangular cooperating gel sealing members (14) and (15).

Upon closing the lid or cover (5), a compressive force is applied to the sealing strip (11) and the gel sealing members (14) and (15) in order to give a tight seal against moisture ingress. When a cable is situated in the cable outlet formed by the cut out portions, (12), (13) the gel sealing members are deformed, as shown in figure 2 and flow to form a seal around the cable. This seal is maintained as long as the compressive force applied by the lid or cover is maintained.

Although it is possible to mould the gel sealing members in situ, as will be described later, it is preferred that each sealing member is separately moulded within a support or cassette (16) as shown in figure 4. The cassette has cut out portions (17) to accommodate the cable, and is of a generally rectangular construction. The gel sealing member is moulded, poured, or cast into the cassette which has its interior surfaces appropriately treated in order that the gel will adhere preferentially to the cassette. This treatment may include, for example, forming holes or depressions in the bottom of the cassette, or roughening the interior surface. As an alternative, it may be possible to secure a block of the gel within the cassette by means of double sided adhesive tape. The cassette is preferably moulded from nylon, or some similar polymeric material.

As can be seen from figure 4, the gel sealing member (15) is moulded so as to be slightly taller than the cassette (14) the additional thickness (18) of material ensuring that the compressive force of the lid or cover is applied directly to the interface between the gel sealing members.

In operation, the lid or cover is opened as shown in figure 1, a plug and cable inserted, and the lid or cover then closed as shown in figures 2 and 3. It is found that this operation may be repeated many thousands of times and the gel sealing members will continue to flow to seal the cable outlet both with and without the cable in Position.

Figures 5 to 13 illustrate alternative sealing members for sealing the cable outlet formed by the cut-out portions (12) and (13).

In figure 5 blocks of gel material (18) and (19) are formed by a two shot moulding into the lid or cover and front plate of the socket assembly. The gel sealing members have deformable teeth (2) which effect the sealing around the cable. Sealing member (19) has a rebated portion (21) which is integral therewith, and anchors the sealing member within the front plate. Figures 6A, 6B and 6C show a further alternative moulded set of sealing members (22) and (23) which have a stepped constructions and blades (24), (25) and (26) which cooperate to seal the cable. Figures 6B and 6C show the sealing members in cross section, with the lid or cover closed, and illustrate how the sealing members can accommodate the different sizes and cross sections of cable, at different exit heights from the plug.

Figures 7A and 7B show a different type of cable sealing member which comprises a pair of brushes, one of which is illustrated at (27) in Figure 7A. The brush comprises a plurality of resiliently deformable bristles, held in place by a moulded collar (28). As illustrated in figure 7B, on insertion of the cable, the bristles are deformed around the cable thereby forming a seal.

Figures 8A and 8B show a generally similar construction, in which the brushes are replaced by fluid-filled bags or sachets of flexible material. The bags may be filled, for example, with air or a silicone oil. Figure 8A illustrates such a bag (29), which is cut away partly to show a fixing means (30).

Figure 9 shows a further type of cable outlet sealing means in which a pair of blades (31) and (32) cooperate to seal the opening. The blades have a wiping contact as the lid or cover is closed, and the edge regions (33) and (34) are compressed together into sealing engagement by the closing of the lid or cover. The blades are deformable to accommodate the positioning of the cable within the cable outlet and may be made of a suitable elastomeric material.

Figure 10 shows a further design of sealing member, which uses a pair of upstanding blades, horizontally split blade (35) and vertically split blade (36), made from elastomeric material. The blades are deformed around the cable when it is inserted in the cable outlet.

In figure 11 the sealing members comprise a split elastomeric bush. Only a fragmentary portion of the bush is shown to illustrate its operation. The upper portion of the bush (37) is fixed in the lid or cover, and the lower portion (38) is carried by the front plate. Upper and lower portions of the bush have semi-circular cut out regions (39) and (40) to accommodate the cable, and the upper portion is a sliding fit within a recess (41) in the lower portion of the bush. Both portions of the bush are made from elastomeric material and are deformable to accommodate a cable situated in the cable outlet. When the cable is not present, the overlap between the two portions of the bush is sufficient to seal the cable outlet.

In figure 12 there is illustrated a pair of sealing members comprising hollow profiled extrusions (42) and (43) formed from a soft elastomeric material. The profiles are in sealing engagement along the line (44) and can deform in order to accommodate a cable pushed between them.

Figure 13A and 13B show yet another form of sealing member which comprises a clam shell arrangement. The sealing member comprises a moulded elastomeric member (45) having a V-shaped opening (46) therein, to accommodate a cable.

Rigid closure members (47) and (48) are integrally attached to the elastomeric member (45) and can be pivoted in a vertical plane about their base regions. Actuating means (49) and (50) shown diagrammatically in figure 13A, push the closure members towards the centre of the cable entry port opening. The actuating means may be operated by the closing of the lid or cover or independently thereof. As the closure members are pushed towards the centre of the cable outlet, they close the V-shaped opening in the elastomeric member (45) thereby sealing the cable outlet.

The elastomeric member can deform around a cable inserted in the V-shaped opening forming a seal therewith.

Figure 14 illustrates, in fragmentary cross-section, a further embodiment of a socket assembly according to the invention in which there is employed an alternative latching mechanism to that shown in figure 1. In figure 14, the latching mechanism, which is shown partly shaded, comprises an extension (51) to the lid or cover (5) which carries a detente (52), which cooperates with a rebate (53) on an upstanding wall (54) integral with the front plate (2). The latch is engaged by downward pressure on the lid or cover and maintains a compressive force on the sealing member (11) and the gel sealing members (14) and (15). The latch may be released by applying pressure to the side wall (55) of the lid or cover (5) which has sufficient resilience to allow the detente to become disengaged.

The reader's attention is directed to all papers and documents which are filed concurrently with this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

Claims

1. An electrical connector assembly comprising: a front plate provided with electrical contacts, a lid or cover moveable between an open position allowing access to the front plate and a closed position in which the front plate is covered by the lid or cover, the front plate and the lid or cover cooperating to form an enclosure adapted to accommodate an electrical connection device and an opening communicable with the enclosure, the opening being adapted to receive an electrical wire or cable, sealing means adapted to form a seal between the lid or cover and the front plate and to seal the opening, when the lid or cover is in its closed position, such that the enclosure is environmentally sealed, the arrangement being such that the enclosure is also environmentally sealed by the sealing means when the lid or cover is in its closed position and a wire or cable is positioned such that it passes through the opening.

2. An electrical connector assembly according to Claim 1, which comprises an electrical socket assembly adapted to receive an electrical plug therein.

3. An electrical connector assembly according to Claim 2, in which the socket assembly comprises a sealed housing.

4. An electrical connector assembly according to any of the preceding claims, in which the enclosure between the front plate and the lid or cover is shaped so as to receive a conventional two-pin or three-pin plug body therein.

5. An electrical connector assembly according to any of the preceding claims, in which the front plate is provided with electrical contacts which are situated behind the face of the front plate and accessible through holes in the front plate.

6. An electrical connector assembly according to any of the preceding claims in which the lid or cover is hingedly connected to the front plate.

7. An electrical connector assembly according to any of the preceding claims in which the lid or cover is resiliently biased towards its closed position.

8. An electrical connector assembly according to any of the preceding claims, in which the lid or cover and the front plate have cooperating cut-out portions which are in register when the lid or cover is in its closed position, defining an opening communicating to the interior of the enclosure, and adapted to receive an electrical wire or cable.

9. An electrical connector assembly according to any of the preceding claims in which the sealing means comprises a first sealing means which forms a seal between the lid or cover and the front plate when the lid or cover is in its closed position, and a second sealing means which seals the opening formed between the lid or cover and the front plate.

10. An electrical connector assembly according to any of the preceding claims, in which the first sealing means extends around or within the periphery of the lid or cover, or around or within the periphery of the front plate, or both.

11. An electrical connector assembly according to Claim 10, in which the first sealing means comprises one or more resilient sealing strips of polymeric material.

12. An electrical connector assembly according to any of the preceding claims, in which the second sealing means is resiliently deformable.

13. An electrical connector assembly according to any of the preceding claims, in which the second sealing means comprises a gel sealing member which, when the lid or cover is in its closed-position, is held under compression within the opening.

14. An electrical connector assembly according to Claim 13, in which a gel sealing member is carried on each of the lid or cover and the front plate, such that when the lid or cover is moved to its closed position the two gel sealing members are compressed against each other and seal the opening formed by the lid or cover and the front plate.

15. An electrical connector assembly according to Claim 13 and 14, in which the gel sealing member or members is carried on a support member.

16. An electrical connector assembly according to Claim 15, in which the gel sealing member has been formed upon, or moulded within, the support member.

17. An electrical connector assembly according to Claim 15 or 16, in which the surface of the support member has been treated such that the gel sealing members adhere more strongly to their respective support members than to each other.

18. An electrical connector assembly according to any of Claims 15 to 17, in which the support member is a cassette, capsule or trough within which the gel sealing member is contained.

19. An electrical connector assembly according to any of Claims 13 to 18, in which two gel sealing members present a flat surface to each other.

20. An electrical connector assembly according to any of Claims 13 to 18, in which two gel sealing members present stepped, or otherwise contoured surfaces to each other.

21. An electrical connector assembly according to any of Claims 15 to 20, in which the gel composition used for the manufacture of the gel sealing members is one which has an adhesive strength to the wire or cable insulation which is less than its adhesive strength to its associated support member and less than its cohesive strength.

22. An electrical socket assembly according to any of Claims 13 to 21, in which the gel sealing member or members have a cone penetration value of greater than 50 and an ultimate elongation of at least 200%.

23. An electrical connector assembly according to any of Claims 13 to 22 in which the gel sealing member or members are electrically insulating.

24. An electrical connector assembly according to any of Claims 13 to 23, which is provided with a latching or locking mechanism adapted to exert a compressive force between the lid or cover and the front plate so as to compress the gel sealing member or members.

25. An electrical connector assembly according to Claim 24, in which the lock or latch mechanism comprises a detente on the lid or cover cooperating with a lip on the front plate.

26. An electrical connector assembly according to any of the Claims 1 to 12, in which the second sealing means comprises brushes, fluid-filled bags, elastomeric blades, elastomeric split bushes, hollow deformable elastomeric shapes, or an elastomeric clam shell construction.

27. An electrical connector assembly according to any of the preceding claims substantially as hereinbefore described with reference to and as illustrated in the accompanying Drawings.

28. An electrical connector assembly substantially as hereinbefore described.