Patent Publication Number: US-2010130042-A1

Title: Connector socket, a connector plug, and an appliance fitted with a connector

Description:
FIELD OF THE INVENTION 
     This invention relates to electrical connectors. 
     The invention is applicable to electrical socket and plug arrangements generally and to appliances including connectors. 
     BACKGROUND OF THE INVENTION 
     Electrical connectors usually include a socket member and a plug member. In many countries, power cable connectors have a three pin socket and plug to connect active, neutral and earth wires. However, special connectors may need to be designed to connect more than three wires. Generally the socket is wired to the building electrical supply, while the plug is attached to the appliance either directly or via a cable. 
     Most socket and plug arrangements are designed so that the connexion is made axially. The socket or plug may include contact blades having a major axis, and the socket and plug are adapted to mate in a direction parallel to the axis of the contact blades. 
     Connectors can also be bulky, and this can be a disadvantage where aesthetics is of concern as well as in, applications in which the appliance must be installed in a confined space. 
     Ceiling lights in office buildings are often installed in the false ceiling below an upper floor. These light fittings can have two or three power wires and one or more control wires connected to them. 
     Plug contacts usually have an elongate shape so a major axis is parallel to the longer dimension of the contact. This axial direction is the direction for plugging and unplugging the plug and socket. Where a plug is integrated into an appliance, the contacts of the plug are normally transverse to the wall of the appliance. This means that the plug extends for a distance transverse to the wall of the appliance so that it projects out from or into the appliance. This can cause problems, for example, where the internal space in the appliance is at a premium, or where it is desired to reduce the overall dimensions of the appliance. 
     SUMMARY OF THE INVENTION 
     According to an embodiment of the invention, there is provided a plug having a receptacle adapted to receive a socket contacts, the receptacle including contact blades being adapted to receive socket contacts inserted transverse to the axis of the contact blades. 
     The plug can include a two or more contact blades which protrude into the receptacle, or which traverse the receptacle. 
     The receptacle can include pairs of opposed slots along a pair of opposed walls through which blades pass. 
     The receptacle can include a mounting register arrangement to prevent incorrect orientation socket. 
     The mounting register can include profiled section to prevent incorrect orientation of socket. 
     The blades can be cantilevered or supported at both ends. 
     The plane of the blades can be transverse to the insertion direction of the socket into the receptacle. 
     The housing of the plug can include a slide attachment arrangement adapted to enable the plug to be attached to the edges of an aperture in the wall of its appliance. 
     Alternatively, the housing of the socket can include such an attachment arrangement. 
     The contact blades include a cable attachment to which a wire of a cable can be attached. 
     The contact blades are part of double-ended contact, the other contact being adapted for connexion with an appliance. 
     The socket includes a connexion protrusion adapted to mate with a receptacle of a plug, and socket contacts adapted to engage with the blades of a plug. 
     The socket includes contact slots which are adapted to receive plug contact blades. 
     The leading edges of the slots can be bevelled to facilitate engagement with the blades. 
     The connexion protrusion is shaped to conform to mounting register of plug receptacle to ensure correct orientation. 
     The connexion protrusion can have a mating profile to match profile of the receptacle. 
     The socket contacts can include wire connexion arrangement. 
     The socket contacts can include spring recess to engage plug blade edge on. 
     The spring can be formed of a pair of complementary folds. 
     The connexion protrusion can be transverse to cable orientation. 
     The socket can include a snap-lock arrangement. 
     A light fitting can be fitted with, a plug according to an embodiment of the invention. 
     The light fitting can include an aperture through which the receptacle can be accessed. 
     The aperture can include cut-outs in a pair of opposed walls, the plug including a slide arrangement adapted to pass through the cut-outs and to engage the edges of the aperture in a sliding manner. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An embodiment or embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective illustration of a socket and plug according to embodiments of the invention; 
         FIG. 2  is a side illustration of the plug of  FIG. 1 ; 
         FIG. 3  is an and illustration of the socket of  FIG. 1 ; 
         FIG. 4A  is an illustration of the socket and plug contacts according to an embodiment of the invention; 
         FIG. 4B  is a side view of a spring contact; 
         FIG. 4C  is a side view of a wire connector; 
         FIG. 5A  top view of the socket of  FIG. 1  with the cover removed; 
         FIG. 5   b  shows detail of the contact slot arrangement of  FIG. 5A ; 
         FIG. 6  is a cut away perspective view of a socket and plug (disconnected) with the plug mounted on a wall; and 
         FIG. 7  is a cut away perspective view of the socket and plug of  FIG. 6  (connected) with the plug mounted on a wall. 
         FIG. 8  illustrates a mounting aperture for a connector in, accordance with an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT OR EMBODIMENTS 
     The invention will be described with reference to a connector adapted for use with a multi-wire light fitting adapted to be mounted in a ceiling of a building. The embodiment relates to a five wire connector arrangement. However, it can be used in other applications. 
       FIG. 1  shows a socket  102  and plug  152  according to respective embodiments of the invention. 
     The socket  102  has a top cover  110 , and a lower housing  112  on which is a socket projection  104  adapted to mate with a receptacle  156  in the plug  152 . The socket projection  104  includes several slots  106  adapted to engage contact blades  158  which are partially exposed in the receptacle  156 . In this example, there are five plug contact blades  158  and five contact receiving slots  106 . A fastening screw or bolt  172  is provided on the plug to enable it to be mounted on an appliance or wall as discussed below. In some instances, there is a need to earth the housing of the appliance. In such cases, an earth tag  173  connected to the earth contact is brought out and fits around the bolt  172  so that, when the bolt is fastened to the housing wall of an appliance, the earth tag  173  is held in electrical contact with the appliance housing. 
     The socket includes a resiliently mounted releasable clip member  114  which has a catch at its lower end adapted to engage with the latch recess  162  on the plug to retain the socket and plug in engagement. 
     The socket projection  104  and the receptacle  156  are preferably shaped to permit these components to mate in only one orientation so that each spring contact in the socket connects with the collect blade in the plug. For example, the slots  106  can be off-set so that the blades can only enter the slots when the socket and plug are correctly oriented. 
     The plane of the plug contacts  158  is substantially upright or transverse to the major plane of the plug  152 . 
     Of course, terms such as upright, vertical, horizontal etc., are used herein in a relative sense using the drawing illustrations as the reference, rather than being referred to absolute references. 
     While the plane of the plug contacts is illustrated as being substantially vertical, the contact blades could be inclined to the vertical provided the receptacle and mating socket projection were designed to accommodate such a variation. That is, the mating direction of the socket projection  106  with the receptacle  156  is parallel to the plane of the plug contact blades. 
     Again, it is to be understood that the location of the  158  blades and the slots  106  could be interchanged between the members  102  and  152  without departing from the spirit of the invention. 
     As shown in  FIG. 4A , the socket  102  includes socket contacts  442  which are formed of a suitable conductive resilient material and which are formed to resiliently engage the contact blades  458 . The spring contacts in this case have a connexion portion  448  for connecting to a wire  440 . This connexion can be by crimping, soldering, welding or other suitable connexion means. To provide the contact pressure to engage the contact blade  458 , the spring contact has first and second bends  444 ,  446  formed in it. As shown in  FIG. 48 , the spring contact has a contact zone  439  where the free end of the spring contact is close to, or in contact with the main stem of the spring contact when the blade  458  is not inserted. The end of the spring can be formed to provide a diverging opening as shown in the region of the contact zone  447  to facilitate insertion of contact blades. 
       FIG. 4C  is a side view of the wire connector  447  of  FIG. 4A . The wire connector includes a triangular shaped arrangement  441 ,  443 ,  455 , with a wire aperture  451  in the base  443 . The side  455  extends beyond the apex  453 . The wire connector is made of resilient conductive material, such as phosphor bronze and can be formed integrally with the connector blade  455 . The wire  449  passes through the aperture  451  and its free end is captured at the apex  453  where the uninsulated wires are held in spring compression between side  455  and side  441 . 
     The plug blade is also illustrated in  FIG. 4A , and includes a substantially rectangular portion  445  adapted to span the receptacle  156  and to seat in slots in the opposed walls of the receptacle. This rectangular portion is also available to engage with the spring contact  442 . At one end, the contact blade  458  includes a connexion portion  447  adapted to be connected to a wire  449  by any suitable connexion method. Alternatively, the end  447  may include a further contact element which con engage with a further mating contact of the apparatus. 
     Either the socket or the plug can be designed to be built into an appliance such as alight fitting. In the example shown in  FIG. 1 , the plug  152  includes a slide mounting arrangement adapted to engage with the edges of a mounting aperture in an appliance. The mounting arrangement includes a projection  164  and a pair of engaging elements  162  on a pair of opposing sides of the plug. The engaging elements  162  are spaced above the projection  164  by a distance which enables the edge of the wall to fit between in a sliding fit. The projection  164  can be part of a projecting peripheral rim which projects beyond the main body of the plug  152 . This arrangement is more clearly illustrated in  FIG. 2 , in which the engaging elements  262  can be seen as spaced above the projection  264 . As shown in  FIG. 8 , an aperture  882  in a wall of an appliance has cut outs  884  along a pair of opposed sides. The aperture  882  is dimensioned so that the main body of the plug, shown in dashed outline, will pass therethrough, but the projecting rim will not pass through when applied “square” to the aperture  882 . The cut outs  884  are located so that the engaging elements  162 ,  162  can pass through the cutouts. Then the plug can be slid along the aperture in the direction of the arrow so that the engaging elements  262  are no longer aligned with the cut outs  882 . 
     The fixing screw  172  can be accommodated in the slot  886  at one end of the aperture  882  and the plug can be fixed in position in the aperture  882  using the screw  172 . 
       FIG. 2  also shows a side view of a connector  270  via which connexion can be made to the circuitry of the apparatus to which the plug is attached. 
       FIG. 3  is an illustration of the main features of the underside of the socket the socket projection  306  has a plurality of slots  322  adapted to receive the contact blades from a mating plug. Each slot passes through a contact isolation box  322  which is open ended at its distal end remote from the body of the socket. The resilient clip arrangement  314  can also be seen. 
       FIG. 5  is a top view of the socket with the cover  110  removed. Slots  506  are visible through upper isolation boxes which are separated form the lower isolation boxes  322  by a “party wall”, i.e., a common wall. Retaining slots  560  in opposed walls of the isolation boxes are adapted to receive the upper portion of the spring contacts (see  442  in  FIG. 4 ). These retaining slots are only of sufficient depth to hold the spring contacts and thus serve to prevent the spring contacts from being pulled through the socket when disengaging force is applied. Strain relief isolating the connexion between the contacts  542  and the wire  540  can also be provided by a “meander” path provided by one or more projections  590 . 
     A cable clamping aperture  520  is adapted to receive a cable and hold it under compression due to the fastening screws  116  ( FIG. 1 ) as they are tightened in the corresponding screw holes  515 . Preferable the aperture  520  includes a raised friction enhancing pattern on its surface. 
       FIGS. 6 &amp; 7  illustrate cutaway views of the socket and plug in the disconnected and connected state respectively, with the plug mounted on a wall  680  through aperture  682 . A spring contact  644  is shown on the socket  602 , and a blade contact  658  is shown on the plug  652 . In  FIG. 7 , the spring contact  744  and the blade contact,  758  are shown in engagement. 
     As seen in  FIG. 6 , the mounting arrangement and the design of the plug provide a low profile mounting arrangement, the minimum limit of which is the height of the engaging elements  262  or the mounting screw. 
     The connector arrangement provides a connector in which the insertion direction is substantially transverse to the main axial direction of the contact blades. In addition the insertion/removal direction is substantially transverse to the cable axis of the cable inserted into the socket. 
     Where ever it is used, the word “comprising” is to be understood in its “open” sense, that is, in the sense of “including”, and thus not limited to its “closed” sense, that is the sense of “consisting only of”. A corresponding meaning is to be attributed to the corresponding words “comprise”, “comprised” and “comprises” where they appear. 
     It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text. All of these different combinations constitute various alternative aspects of the invention. 
     While particular embodiments of this invention have been described, it will be, evident to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. The present embodiments and examples are therefore to be considered in all respects as illustrative and not restrictive, and all modifications which would be obvious to those skilled in the art are therefore intended to be embraced therein.