GB2065992A - Self-sealing socket - Google Patents

Abstract

A socket (12), which is self- sealing, includes a bore (20) housing a spring (26) and a plunger (28), which are connected together. A flexible gasket (30) on the outer lip opening of the socket (12) includes a hole which receives a portion of the spring loaded plunger (28), thus sealing the socket against moisture penetration. When a pin (54, figure 2 not shown) is inserted into the socket (12), it forces the plunger (28) back into the bore (14), compressing the spring, and the pin (54) then acts with the gasket (30) to provide a seal, while it also makes electrical contact with the bore (14) of the socket. The plunger (28) may be made from insulating material to provide a safe front end and prevent potential shock hazard from the unmated connector. <IMAGE>

Description

SPECIFICATION Individual socket contact seal This invention relates to an electrical connector.

When using electrical connectors in places where moisture is present, such as aboard ships and other areas around the sea, it becomes imperative to prevent moisture from coming in contact with the metal electrical contact, particularly in the regions of the contacts where actual electrical connection between sockets and pins are to take place. This is particularly important for socket contacts because it is very difficult to see if moisture is present in the socket, and moisture is easily retained in the socket because the socket forms a well.

Of course, moisture is usually not such a problem while the connector halves are together and corresponding pins have been inserted in the sockets, simply because the socket-to-pin connection serves as a moisture seal itself.

However, when the connector halves have been removed from one another, and the receptacle contacts are exposed to the elements, moisture penetration into the sockets becomes a major problem.

Obviously, if moisture is allowed to penetrate within the contact portions of the sockets, corrosion, as well as electrical short-circuiting, could result, thus causing poor electrical continuity when corresponding pins are inserted into the sockets as well as a shock hazard.

One means of overcoming this moisture problem is to close the entry of the connector half which contains the sockets with a cap which normally screws onto the end of the connector half, thus sealing the moisture away from the sockets. However, this mechanism often requires that a dock worker or seaman remembers to put the cap on after the connector halves have been unmated. Furthermore, often the connector halves are unmated in heavy seas while moisture is all around, and thus moisture might enter the sockets before the cap can be placed over the connector nalf Another way to overcome this moisture problem has been attempted in automatically sealing the sockets from moisture when the connector half containing the pins have been withdrawn from the sockets. One such attempt to do this is disclosed in U.S.Patent No. 3,119,645 which shows a multi-pin electrical connector, which uses an insert made of a viscose silicone type grease. The grease is situated between a plastics insert and the connector housing which holds the sockets. Each socket contains a spring connected to a follower. The spring is compressed inwardly in the socket when a pin is inserted therein through the viscose grease. When the pin is retracted, the follower extends outside of the barrel of the socket and into the viscose grease layer, thus, allegedly, sealing the socket from moisture by the fact that the grease will flow about the follower. As can be seen, the sealing mechanism used in this patent is a layer of grease for all of the sockets rather than being individualized.One problem which may arise is that the grease may stay on the follower and be pulled into the socket itself when the pin is pressed against the follower, thus causing conductivity problems. Furthermore, it is uncertain as to what keeps the grease from leaving the connector through the hole in the plastic insert which receives the pin. Also, the system of the patent is very difficult to manufacture and very messy to use.

According to the invention there is provided an electrical socket comprising an elongate socket contact adapted to mate with a corresponding pin contact, said socket contact having an elongate bore therein; an elongate spring member received in the said bore and in contact with its rearward portion and a plunger also received in the said bore, which is adapted to protrude through its forward open portion, while said spring is elongated, said spring member being connected ta said plunger; and a gasket attached to the open end of said socket contact, said gasket having a hole therethrough for receiving said plunger when the pin is removed from the socket, and for receiving the pin when the pin. is inserted in the socket, said gasket and said plunger sealing the bore in said socket from moisture penetration therein.

The invention and embodiments thereof provide an electrical connector having an improved means for sealing its electrical contacts from moisture, and having a safe front to prevent shock hazard.

In the accompanying drawings: Figure 1 is a partial side view of an electrical connector housing showing a cross-section of a socket contact in accordance with the invention; Figure 2 shows the connector and socket contact of Figure 1 with a pin inserted into the socket; Figure 3 is a front view of the connector of Figure 1, showing four sockets; Figure 4 is a pictorial view of a socket contact of Figure 1, showing an associated pin contact aligned therewith; and Figure 5 is a pictorial view of the gasket seal used on the socket contact of Figure 1.

Figure 1 shows a portion of an electrical connector housing 10, receiving at least one electrical socket contact 12. The socket contact 12 is received in a bore hole 14 which extends through the housing 10. The housing 10 is normally made of an electrically insulating material such as a plastics material. The socket contact 12 is crimp-terminated to electrical conductor 1 5 at its rear end. The socket contact is retained within the bore hole 14 by the action of fingers 1 6 of a collet 1 7 pressing against a shoulder 1 8 of the socket contact.

The socket retention mechanism as shown herein may be better seen and understood by referring to U.S. Patent 3,335,396 which is incorporated herein by reference. The socket contact itself is normally a machined contact made of an electrically conductive material, such as a copper alloy. The socket contact includes longitudinal bore hole 20 which has a closed end portion 22 and an open end portion 24. A spring member 26 is received within the bore hole 20.

One end of the spring member 26 abuts against the closed end 22 of the bore hole. A plunger 28 is attached to the other end of the spring member 26. This plunger is normally made of an electrically insulating material, such as polytetrafluoroethylene. The open end of the socket has, in this embodiment, a flexible silicone rubber gasket 30 attached thereto. The shape of the gasket, which is generally toroidal, may be better seen in Figure 5, which is a pictorial view of the gasket 30.

As can be seen, the gasket 30 includes a rim portion 32 which is received over the outside end portion of the open end section of the socket. The silicone rubber gasket is not bonded to the socket, but is free-floating and centralized by the plunger or pin contact. As can be seen from Figure 5, the gasket 30 includes a hole 34 therethrough for receiving the end portion 36 of the plunger 28 when there is no pin contact in the socket as shown in Figure 1.

The gasket 30 is very flexible, and its rim is capable of axially expanding and also expanding forward. The diameter of the hole 34 in the unexpanded position (not shown) is slightly smaller than the diameter of the plunger 28 in the vicinity of circumference 38 where the plunger will make a sealing contact with the gasket. This causes gasket 30 to expand outwardly and axially along the periphery of the hole 34 as shown at position 40 in Figure 1 when the plunger makes contact with the gasket.

The spring member 26 applies spring pressure to this plunger, forcing it through the gasket hole 34, thus expanding it axially and forwardly, creating the seal about the circumference 38.

Furthermore, the collet 1 7 also applies forward pressure to the entire socket assembly, further enhancing this seal. The plunger 28 is retained within the socket bore by a pinion 42 which extends into bore hole 44 of the plunger. A portion of the pinion 42 projects above the plunger and abuts against a shoulder 46 as the plunger and thus the pinion move longitudinally within the socket. When the pin contact is inserted, the pinion 46 will ride along a siot 48, which is also indicated in Figure 4.

Again referring to Figure 1, a flat spring member 50 is provided within a slot 52 of the socket to provide spring pressure contact against a corresponding pin contact, which may be inserted into the socket. This may be better seen in Figure 2.

A more detailed description of the flat spring 50 may be found in U.S. Patent 3,384,866, which is incorporated herein by reference.

Referring now to Figure 2, there is shown the socket contact of the Figure 1 with a pin 54 inserted therein to make electrical contact with the socket 12 along the inside surface of the bore of the socket. As can be seen from Figure 4, the pin 54 is first aligned with the end 36 of plunger 28, making contact therewith, and the pin is pressed into the bore 20 of the socket, causing the spring member 26 to compress and moving the plunger in the rearward direction of the socket.

The corresponding connector body housing the pin (not shown) may lock the pin into the socket by suitable means, such as that shown in Patent Application No.801 5144, filed 7th May 1980 in the name of the present applicant.

As can be seen from Figure 2, the volume of displacement of the cut-out portion 58, which houses the gasket 30, is slightly larger in volume than the gasket, thus permitting the gasket to expand and to contract as the plunger 36 is inserted therein. Furthermore, it may be seen that the pin itself fits into the hole 34 in the gasket, also providing a seal to keep moisture from entering into the socket, even while the connector halves are mated. The forward section of the socket is retained by a shoulder 60 in the connector housing. The seal is retained within its housing also by means of the shoulder 60.

As can be seen, the plunger, together with the gasket 30, acts as a seal against moisture penetrating into the bore 20 af socket contact 12, thus preventing rust-out of the bore, as well as possible electrical shorts. Furthermore, the plunger also acts as an alignment guide for the corresponding pin 54 to enter into the socket bore.

Figure 3 shows an end portion 56 through the plunger 28 as well as the gasket 30. Furthermore, the plunger also centralizes the gasket about the open end of bore hole 20 so that the seal will not easily be damaged when the pin 54 is inserted through the hole 34 in the seal and into the bore of the socket. Also, since the seal and the plunger are made of electrically insulating material, a user would not be exposed to electrical shock since what he would come in contact with (referring to Figure 3), would be all insulaticn material, namely, the end 36 of the plunger, which is of polytetrafluoroethylene, and the seal 30, which is of silicone rubber. Thus, the associated sockets are not only protected against moisture, but they also protect any users against shock hazards by this combination of seal and plunger.

This seal is preferably made of a specialized lubricated silicone material which will also withstand arcing and moisture attack.

An electrical connector having one of its connector halves open, housing the sockets described above, was tested with water from a fire hose being sprayed directly against the end face 62 of the connector at 208 1/minute with 1 kg/sq.

cm pressure for 5 minutes from a distance of 3 to 3- m. After this test, the contacts were removed, and there was no preceivable moisture within the socket bores.

Claims (9)

1. An electrical socket comprising an elongate socket contact adapted to mate with a corresponding pin contact, said socket contact having an elongate bore therein; an elongate spring member received in the said bore and in contact with its rearward portion and a plunger, also received in the said bore, which is adapted to protrude through its forward open portion, while said spring is elongated, said spring member being connected to said plunger; and a gasket attached to the open end of said socket contact, said gasket having a hole therethrough for receiving said plunger when the pin is removed from the socket, and for receiving the pin when the pin is inserted in the socket, said gasket and said plunger sealing the bore in said socket from moisture penetration therein.

2. An electrical socket as claimed in Claim 1, wherein said gasket is made of a flexible material and is arranged to expand radially and outwardly when it receives said plunger.

3. An electrical socket as claimed in Claim 2, wherein the diameter of said plunger is larger than the unexpanded diameter of the hole in said gasket.

4. An electrical socket as claimed in any preceding claim, wherein said spring member places force on said plunger, thus forming a seal between the inner periphery surface of said gasket and the outer periphery surface of said plunger, flexing said gasket outwardly and expanding the diameter of the hole in said gasket.

5. An electrical socket as claimed in any preceding claim, wherein said gasket is substantially toroidal in shape said plunger centralizing said gasket on the opening in the bore of said socket and serving as a guide for the corresponding pin contact to enter the bore of said socket.

6. An electrical socket as claimed in Claim 5 wherein there is constant contact between the said gasket and said plunger or said gasket and the corresponding pin contact to provide a continuous moisture seal.

7. An electrical socket substantially as herein described with reference to the accompanying drawings.

8. An electrical connector comprising a socket according to any preceding claim mounted in a housing.

9. An electrical connector as claimed in Claim 8, wherein said gasket is mounted in a space between the ends of the socket contact and the inside of the housing, said space being larger than the gasket to permit radial and outward expansion of said gasket.