Technical Field The present invention relates generally to electrical connectors, and in particular, although not exclusively, to plugs and jacks for use with electrical equipment, such as headsets.

Background

Jack and plug connectors are known to enable a user equipment, such as headphones, to be connected to a host equipment, such as a passenger entertainment system. Whilst the plug is inserted in the jack it is possible that the user will move the headphones relative to the point of connection between the plug and the jack. If the user attempts to move the headphones beyond the length of the cable (which connects the plug to the headphones) a force will be applied to the plug and the jack by the cable. This means that cable, the jack and/or the plug could be damaged as a result of the force applied. We have realised that it would be advantageous to provide an improved electrical connector.

Summary According to a first aspect of the invention there is provided a plug for electrical equipment, the plug comprising a forward space for receiving a counterpart socket therein, the plug further comprises an electrical contact provided on a wall surface, which wall surface at least in part surrounds said space, the plug further comprises a plug projection extending from a base of the space into said space.

Preferably the wall surface is provided on a wall which completely surrounds the space.

The wall surface extends substantially perpendicularly of the base. The electrical contact is preferably at the marginal periphery of the space .

The electrical contact is preferably contained within the space . Preferably a plurality of electrical contacts are provided. Preferably the electrical contacts are located at respective regions of the wall surface. Preferably at each region a plurality of electrical contacts are provided. Preferably the electrical contacts are provided at two respective regions. Preferably the plug projection is non-current carrying. Preferably the plug projection is of electrically insulative material.

Preferably a plurality of plug projections are provided. The plug may be viewed as being of cap form, wherein the wall surface forms a depending skirt from the base. The plug is preferably capable of fitting over the socket with which the plug is arranged to interface .

The space preferably has rounded vertices.

According to a second aspect of the invention there is provided a socket for electrical equipment comprising a front end portion and a side portion, and an electrical contact is provided on the side portion to face externally of the side portion and the end portion is provided with an aperture arranged to receive a plug projection.

The electrical contact is preferably laterally outer of the front end portion.

The side portion preferably defines an outer peripheral surface of the socket. The electrical contact is preferably resiliently deformable laterally of the socket. The electrical contact preferably outwardly curved/bowed of the side portion.

The side portion preferably defines an inclined/bevel surface .

The aperture is preferably capable of receiving an electrical pin having a diameter in the range 2mm to 7mm. The socket preferably comprises an electrical terminal associated with the aperture to allow use of a pin provided with an electrical contact to electrically connect with the terminal of the aperture. The socket is preferably arranged to be secured to a bulkhead panel or other supporting structure .

According to a third aspect of the invention there is provided a plug and socket assembly comprising the plug of the first aspect of the invention and the socket of the second aspect of the invention.

The plug is preferably a manual push fit onto the socket.

Brief description of the Drawings

One embodiment of the invention will now be described, by way of example only, with reference to the following drawings in which:

Figure 1 is a perspective view of a plug,

Figure 2 is a perspective view of a plug and a socket, and

Figure 3 is a cross-sectional perspective view of the plug and socket of Figure in an interfaced condition.

Detailed Description

With reference initially to Figure 1 there is shown a plug 1 , suitable for attachment to a user equipment, such as an audio headset. As will be described below, the plug 1 is advantageously arranged to interface with a counterpart socket, or jack, such that in the event that the user (for example the headset wearer) moves beyond the length of the cable connecting the equipment to the plug, the plug can easily break away from its mating, in a quick-release manner, with the socket without damage to the plug or the socket. The plug 1 comprises a housing which comprises a side wall 2. The (inner surface of) side wall 2, together with a base 3 define a space 4. The wall 2 extends substantially perpendicularly forwardly of the base 3. The wall 2 defines an inwardly facing surface 2a. The surface 2a surrounds the space 4. At two respective locations on the surface 2a there are each provided electrical contacts 5a and 5b. The electrical contacts 5a and 5b each comprise three spaced-apart electrical contact portions. The electrical contacts allow electrical signals (containing data and/or power and/or signalling) to and from the user equipment by way of the cable 30. The cable 30 extends from the housing of the plug by way of a cable entry region 7. Each of the electrical contacts comprises a substantially semi-cylindrical portion and a respective headed portion at one distal end thereof. Also provided on the inner surface 2a there are provided three formations 5c, of substantially the same shape as the electrical contacts 5a and 5b, but unlike contacts 5a and 5 are non-current carrying. As will be described below, the formations 5c serve to locate the plug to the socket when in the mated condition. Extending from the base 3 there provided plug projections 6a, 6b and 6c. The plug projections 6a and 6b are of substantially the same size, whereas the plug projection 6c is of smaller diameter as compared to the plug projections 6a and 6b. The plug projections are arranged in triangular formation so as to allow them to be inserted into a standard 3 -pin socket arrangement, for the purpose of aiding the correct alignment.

Reference is now made to Figure 2 which shows a socket 10 which is interfaceable with the plug 1. The socket 10 is arranged to be secured to a suitable supporting structure, such as a bulkhead panel in an aircraft, by way of suitable fixings (not illustrated). The socket 1 comprises an end portion 1 1 and a side portion 12. The side portion 12 presents a bevel or sloping surface. The side portion 12 is provided with two groups of electrical contacts 15a and 15b. The groups of electrical contacts 15a and 15b each comprise three electrical contact portions. The electrical contacts face outwardly of the socket 1 , and as will now be described are arranged to mechanically and electrically interface with counterpart electrical contacts of the plug 1. A location protrusion 15c is also provided on the socket 10 and is arranged to achieve locating engagement with the formations 5c to assist in locating the plug on the socket in the attached condition. The end portion 1 1 is provided with three apertures 13a, 13b and 13c. Internally of the apertures there are provided respective electrical terminals which are connected or connectable to corresponding electrical circuitry which is connected to the electrical contacts 15a and 15b. When used with the plug 1 , the plug projections 6a, 6b and 6c advantageously are received in the respective apertures and serve as a locating function when the plug is attached to the socket. However, the plug projections are of such a length that in the event that the plug is caused to detached from the socket the plug projections easily exit from the apertures and do not in any impede the detachment process. The interaction between the plug and the socket in the mated condition is now described, with reference to Figure 3. The contact portions, here those of contacts 15b, are bowed laterally outwardly of the side portion 12. The contact portions are arranged to be resiliently deformable laterally of the socket 10. As can be seen, when the plug 1 is pushed onto the socket 10, the respect electrical contacts of each of the plug 1 and the socket 10 are forced into engagement with each other and in so doing cause the electrical contact portions of the socket to deflect inwardly of the socket. This frictional engagement between the respective electrical contacts not only ensures good electrical connection but also a detachable mechanical attachment between the plug and socket which is sufficient to maintain the plug attached to the socket, but is nevertheless allows for the plug to become detached in a quick-release fashion from the socket in the event that the user attempts to move the user equipment to a point which exceeds the length of the cable 30. Advantageously, the quick- release detachment is brought about regardless of which angle the cable 30 is pulled at.

It should be appreciated that in the event that the plug is caused to become released from attachment with the socket, this process is facilitated by virtue of the (rigid or semi-rigid) cable entry portion of the 7 of the plug providing leverage resulting from the pulling force applied by the cable 30. Advantageously, the socket 10 is backwards compatible in that it is capable of also allowing a known plugs (with electrical pins) to be used therewith, for example of the type which comprise a pin in which the various terminals are spaced along the length of the pin (and electrically isolated from each other). On insertion of such a known plug type, the, or each, of the terminals of the (known) pin will contact a respective terminal contact located internally of the apertures. The socket 10 therefore has the versatility to accept the plug 1 , or a known plug type, and so is not restricted to use of the former. Although the above embodiment finds particular application in the field of headphones (and is of particular advantage in the field of (inflight or otherwise) passenger entertainment), modified embodiments also find application in relation to plug and socket arrangements for transmission of data generally, or indeed any electrical signal, and not solely audio signals and/or power.