GB2261774A

GB2261774A - A connector/adaptor

Info

Publication number: GB2261774A
Application number: GB9202478A
Authority: GB
Inventors: Rex Bowers
Original assignee: National Power PLC
Current assignee: National Power PLC
Priority date: 1991-10-28
Filing date: 1992-02-05
Publication date: 1993-05-26
Anticipated expiration: 2012-02-05
Also published as: GB2261774B; GB9202478D0; GB9122823D0

Abstract

A connector comprises a body with pins (5, 7) for reception in a socket outlet. The body comprises front and back portions which are hinged together, the axis (20) of the hinge being spaced from a peripheral edge (16) of the connector and adjacent to the front face (25) thereof. The back portion (13) has a part (16) extending between the hinge (20) and the peripheral edge (16), whereby the part (16) protrudes beyond the front face (25) when the portions are opened. The protrusion may prevent electrical connection between the pins and the socket outlet. The connector body may clampingly receive a two-pin plug and thereby act as an adaptor (fig 10, not shown). The two parts of the body may be secured by a captive screw (73, figs 17, 18 not shown) held in a cavity of the connector. The screw has a relatively thin shank between a screw-threaded end and a head end. The cavity traps the screw end when the screw is not in use. A hole in the cavity is screw threaded so that the screw may operatively protrude from it. Another hole in the cavity receives the shank. <IMAGE>

Description

A CONNECTING DEVICE This invention relates generally to connecting devices which enable the terminals of an appliance to be connected with an electrical socket, where the device comprises a body with pins designed for reception in the socket and where the body of the device is adapted to enclose the terminals of the appliance. More particularly, the invention relates to electric plugs which are designed for connection with the cable of an appliance, and to electric plug adaptors which enable a plug of one standard to be connected to a socket of a different standard and where the body of the adaptor is designed to enclose the plug. An adaptor of this kind is described in EP-A-0342942.

One particular problem with designing such connecting devices is that they must meet all the safety standards required by certain regulatory bodies such as the Association of Short Circuit Testing Authorities (ASTA) and the British Standards Institution (BSI).

An object of the present invention is to provide a safer connecting device, which meets the required safety standards.

Another object of the present invention is to provide an electric plug adaptor which is compatible with plugs having bodies with a range of different shoulder geometries.

Accordingly, a first aspect of the present invention provides a connecting device enabling the power cable of an appliance to be connected with an electrical power receptacle by means of the device and comprising a body with pins designed for reception in said receptacle, the body of the device being adapted to enclose connection means for connecting the power cable as required to the pins of the device, wherein the body comprises front and back portions which are hinged together to permit the body to be opened for access to said connection means, the axis of the hinge being spaced from a peripheral edge of the device and adjacent to the front face thereof and the back portion having a part extending between the hinge and said peripheral edge, whereby said part protrudes beyond said front face when the portions are opened.

In one embodiment, the connecting device may comprise an electric plug, and the connection means enables an electric cable of the appliance to be connected with the pins of the device.

Another embodiment of the connecting device may comprise an electric plug adaptor enabling a plug one standard to be connected by means of the adaptor with the terminals of a receptacle of a different standard, wherein the body is adapted to enclose the plug with the pins of the plug connected as required to the pins of the adaptor.

Preferably the part protrudes sufficiently far beyond said front face, when the portions are opened, to prevent electrical connection between the pins of the device and the terminals of the receptacle.

In a preferred embodiment the hinge comprises a stub which is integrally formed with the front portion and extends along the hinge axis, and a complementary recess formed in said part for accommodating the stub.

Alternatively, the stub may be integrally formed with said part, the front portion having a recess for accommodating the stub. In the latter case, the stub may extend either side of the part.

In either case, the connecting device preferably includes means to urge, in a direction generally along the hinge axis, the part and the front portion together to retain the stub engaged in the recess. The means to urge preferably comprises an abutment which is spaced from the hinge axis and which slidably engages with a face of the part normal to said axis.

Preferably the part is formed as a plate such that the back and front portions of the body can be formed separately and connected together by forcing the plate between the front portion and the abutment, distorting the plate until the stub and recess snap into engagement.

In a preferred embodiment the back portion has two parts extending between the hinge and the peripheral edge, and the parts are spaced apart and parallel to one another. In this embodiment, preferably each part comprises a plate having or engaging respective oppositely directed stubs.

The two parts may be positioned either side of one of the pins of the connecting device.

In a preferred embodiment the peripheral edge is the upper edge of the connecting device. This is particularly convenient if the device is designed for reception in a British standard 13 Amp socket where the earth pin is positioned nearest to the upper edge of the device.

In a preferred embodiment of an electric plug adaptor the body includes an abutment surface to support a front face of the plug and a pair of opposed resilient flaps each secured at one end and arranged to bear on opposite side edges of the plug to urge the plug against the abutment surface.

Accordingly, a second aspect of the present invention provides an electric plug adaptor enabling a plug of one standard to be connected by means of the adaptor with the terminals of a receptacle of a different standard, and comprising a body with pins designed for reception in said receptacle, the body being adapted to enclose said plug with the pins of the plug connected as required to the pins of the adaptor, wherein the body comprises two cooperating portions which enable the body to be opened to insert the plug and the body includes an abutment surface to support a front face of the plug and a pair of opposed resilient flaps each secured at one end and arranged to bear on opposite side edges of the plug to urge the plug against said abutment surface.

In a preferred embodiment, a part of each of the flaps adjacent to said one end extends generally towards the lower side of the body with the remainder of each of said flaps pointing inwardly and upwardly away from the lower side.

The abutment surface and the flaps may comprise a separate unit which is removeable from the body of the adaptor.

Alternatively the abutment surface and the flaps may be formed in the front portion.

The resilience of the flaps may allow a degree of movement between the plug and the adaptor. In circumstances where this is undesirable, means may be provided to prevent the flaps from flexing beyond a pre-determined point when the body of the adaptor is closed. Such means preferably includes abutment means to limit the movement of the bent portions of the flaps, when flexed, towards the lower edge containing the entry port for the power cable. In addition, where a lateral edge of each of the flaps is spaced from an adjacent face of the front portion, a further abutment means is provided to engage the lateral edge to prevent movement of the flaps on insertion of a plug. The means may also include locking means to lock the flaps in the position the flaps adopt when bearing on opposite side edges of the plug.

Preferably, the locking means automatically locks the flaps in position when the body of the adaptor is closed.

In some circumstances it may be unnecessary or undesireable to lock the flaps in position and the locking means may be arranged to be operative only when the adaptor is used with plugs having a pre-selected range of shoulder geometries.

In a preferred embodiment the body of the adaptor comprises front and back portions. Conveniently, the locking means may comprise a pair of protrusions extending from an internal face of one of the portions, a respective protrusion arranged to engage a respective flap when the body of the adaptor is closed. Alternatively the locking means may comprise a plurality of protrusions extending from an internal face of one of the portions and arranged to sit either side of the flaps when the body of the adaptor is closed.

In a preferred embodiment the locking means is arranged on the back portion.

According to a third aspect of the present invention there is provided a connecting device enabling the power cable of an appliance to be connected with an electrical power receptacle by means of the device and comprising a body with pins designed for reception in said receptacle the body of the device being adapted to enclose connection means for connecting the power cable as required to the pins of the device, wherein the body comprises front and back portions which enable the body to be opened for access to said connection means, and a screw, the front portion having a channel to receive the screw, which screw can be screwed into the back portion for securing the two portions together to close the body, the screw having a head accessible in use, from a front face of the device and a threaded portion connected to the head by a shaft of diameter less than said threaded portion, wherein said channel includes a central chamber and a respective restricted portion on each side of the chamber whereby the threaded portion of the screw can be received freely in the central chamber when unscrewed to open the body so that the head of the screw extends beyond the front face of the device, the restricted portions then preventing substantial inwards or outwards movement of the screw without turning the screw.

In one embodiment, the device may comprise an electric plug, and the connection means enables an electric cable of the appliance to be connected to the pins of the device.

In another embodiment, the device may comprise an electric plug adaptor enabling a plug of one standard to be connected by means of the adaptor with the terminals of a receptacle of a different standard, wherein the body is adapted to enclose the plug with the pins of the plug connected as required to the pins of the adaptor.

In a preferred embodiment, the head of the screw protrudes sufficiently far beyond the front face of the adaptor when said threaded portion is completely located within said central chamber to prevent electrical connection between the pins of the device and the terminals of the receptacle.

Examples of embodiments of the present invention will now be described with reference to the drawings in which:- Figure 1 shows a side view of a connecting device according to an embodiment of the present invention; Figure 2 shows a view of the lower side of the connecting device shown in Figure 1; Figure 3 shows a side view of the connecting device shown in Figure 1 with the back portion in two stages of being opened; Figure 4 shows a view of the front face of the connecting device with the back portion fully opened; Figure 5 shows a plan view of a preferred embodiment of a hinge arrangement; Figure 6 shows a side view of the hinge arrangement shown in Figure 5; Figure 7 shows a cross-sectional view of the hinge arrangement shown in Figures 5 and 6, along the hinge axis AA;; Figure 8 shows a view of the inside of an embodiment of the connecting device with the back portion fully opened, adapted for use as an electric plug adaptor; Figure 9 shows a view of a separate removable unit for locating and holding the plug inside the adaptor shown in Figure 8; Figure 10 shows a view of the inside of the adaptor shown in Figure 8 as used with a two pin plug; Figure 11 shows an expanded view of the inside of the lower part of the front portion of the adaptor; Figure 12 shows a side view of the adaptor along AA; Figure 13 shows schematically a part cut away view of an embodiment of an adaptor when closed, and a section on BB; Figure 14 shows a cross-section of the embodiment shown in Figure 13 on AA; Figure 15 shows schematically a part cut away view of an embodiment of the adaptor when closed, and a section on DD;; Figure 16 shows a cross-section of the adaptor shown in Figure 15 on CC; Figure 17 shows schematically a part cut away view of an embodiment of an electric plug adaptor when closed; Figure 18 shows a cross sectional view of an arrangement for securing the front and back portions of the connecting device together, and Figure 19 shows a cross sectional view through part of the connecting device shown in Figure 13, with the body of the device open.

Referring to figures 1 and 2, a connecting device 1 is shown having a body 3 and three pins 5, 7 and 9 arranged for compatibility with a standard British 13 Amp socket. The body 3 comprises a front portion 11 and a back portion 13 which are hinged together to permit the body 3 to be opened for access to the connection means of an appliance. The connecting device may comprise an electric plug, in which case the connection means would be, for example, the bare ends of an electric power cable which would be connected to the pins of the connecting device as required, for example by screw clamping.

Alternatively, the connecting device may comprise an electric plug adaptor enabling a plug of one standard to be connected with the terminals of a receptacle of a different standard and where the body of the device is adapted to enclose the body of the plug. In this case the connection means are the pins of the plug which would be connected to the pins of the connecting device as required. An aperture 14 or 15, depending on whether the connecting device is an electric plug or electric plug adaptor, respectively, is formed in the lower side 17 of the body of the connecting device. Aperture 15 is preferably sized to accommodate plugs having shoulders of a range of different dimensions. In the example shown the device is conveniently in the shape of a standard British three pin plug.

Figure 3 shows the connecting device 1 in two stages of opening. The front and back portions open about a hinge 19 whose axis 20 is positioned away from the upper peripheral edge 16 and adjacent to the front face 25 of the device 1.

Referring to figure 4, the back portion 13 has two parts 21 and 23, which are generally in the form of tab-like projections or plates, and extend between the hinge 19 and the upper peripheral edge 16. Two slots 27 and 29 are formed in the front portion 11 either side of the earth pin 5 to accommodate parts 21 and 23. The slots extend from the upper peripheral edge 16 to below the hinge 19.

Figures 5 to 7 show in more detail the features of a preferred embodiment of the hinge 19. The hinge 19 comprises two oppositely directed stubs 115 and 117 integrally formed in the front portion 11 of the connecting device and extending along the hinge axis. A complementary recess 119 and 121, which can be a through hole, as shown, is formed in each of the plates 21 and 23 to accommodate a respective stub. Plates 21 and 23 are preferably made from a resilient material such as plastics. This facilitates fitting the plates 21 and 23 over their respective stubs 117 and 119. By necessity, the width of the gap 123 and 125 between the end of the stub and the front portion must be equal to or greater than the thickness of the plates 21 and 23. In this case it may be relatively easy to dislocate the hinge 19 and separate completely the back portion 13 from the front portion 11.Removal of the back portion from the front portion renders the connecting device potentially dangerous, since the connecting device could be plugged into a live socket in this condition.

In order to strengthen the hinge 19 i.e. to prevent the plates from being easily detachable from the front portion, an abutment 127 is provided which is spaced from the hinge axis 20 as shown in Figures 6 and 7. The abutment protudes beyond the inner face of each slot 27 and 29 and engages with the adjacent face of each of the plates 21 and 23. Thus the abutment 127 forces the plates 21 and 23 and the front portion 11 together to retain each of the stubs 115 and 117 in their respective recesses 119 and 121. The plates are sufficiently resilient so that the front and back portions of the body can be connected together by forcing each of the plates between the front portion and the abutment 127, distorting each of the plates until a respective stub and recess snap into engagement.

The abutment 127 can also be arranged to retain the earth pin 5 as shown. A plate 129 extending perpendicularly from the abutment 127 engages with an inner face of the back portion 13 when the connecting device is closed, in order to strengthen the abutment 127 when force is applied to the earth pin on inserting the connecting device into a socket.

When the front and back portions are closed, parts 21 and 23 are substantially flush with the front face 25 and the connecting device has the outward appearance shown in figures 1 and 2. However, when the front and back portions are opened, parts 21 and 23 protrude beyond the front face 25.

In the particular embodiment shown, when the connecting device is open, parts 21 and 23 protrude sufficiently far beyond the front face 25 to prevent the pins of the device making electrical contact with the terminals of the socket. Thus any exposed electrically conducting paths in the device will remain isolated from a mains or other power supply if an attempt is made to insert the device into a socket when the device is open.

If the connecting device is in a semi-open condition, inserting the device into a socket will tend close the back portion 13 by virtue of parts 21 and 23 acting against the face of the socket.

Conversely, if the connecting device, in the closed position, is already located in a socket, and sufficient force is applied so as to open the back portion 13, parts 21 and 23 will tend to prize the device out of the socket. This action will disconnect the pins of the device from the terminals of the socket.

The above safety measures ensure that the connecting device may only carry electricity when the body of the device is closed, reducing the risk of exposure to live parts, by a user, to an absolute minimum.

In the embodiment shown, the hinge axis 20 runs parallel to the top edge 16 of the front portion 11.

However, this need not necessarily be the case and any other orientation of the hinge axis 20 is contemplated which permits the body 3 of the device to be opened. For example, the hinge axis 20 may be parallel to one or other side 33, 35 of the device body 3, so that the back portion 13 is opened from a respective side.

Although the particular embodiment shown has two parts 21 and 23, it is contemplated that only one is necessary, but more than two may be required or desirable depending on the application. As shown in figures 3 and 4 parts 21 and 23 are in the form of tab-like projections.

However it is envisaged that parts having different shapes and sizes may be necessary or desirable depending on the application.

A screw 73 is provided to secure the front and back portions 11 and 13 together when the device 1 is closed.

The screw 73 and the connecting device may be arranged in such a way that the screw head remains protruding from the front face 25 of the device 1 when the front and back portions 11 and 13 are not secured.

The following is a description of a connecting device adapted for use as an electric plug adaptor.

Figure 8 shows a view of the inside of the body 3 of the adaptor 1 when the back portion 13 is fully open. A panel 37 provides an abutment surface 39 to support the front face of a plug. A pair of opposed resilient flaps 41 and 43, each secured at one end are arranged to bear on opposite side edges of a plug, so as to urge the plug against the abutment surface 39. In the particular embodiment shown, a part 42, 44 of each of the flaps, adjacent to the secured end, extends generally towards the lower side 17 of the body of the adaptor with the remainder 46, 48 of each of the flaps pointing inwardly and upwardly away from the lower side 17.

Flaps 41 and 43 are designed so that plugs having shoulders of various widths and shapes may be accommodated within the body of the adaptor.

Figure 9 shows the panel 37 providing abutment surface 39 and flaps 41 and 43 comprised in a separate unit 45 which may be completely withdrawn from the inside of the body 3 of the adaptor 1. Unit 45 may be moulded complete from any suitable material, the material preferably being an insulator such as plastics.

Alternatively, the abutment surface 39 and flaps 41 and 43 may be integrally moulded with the front portion 11 of the adaptor, as may be preferred.

Figure 10 shows an example of the adaptor designed for use with a continental-style two pin plug 47. The front face 49 of the plug is positioned against the abutment surface 39 of panel 37. Terminals 51 and 53 are provided within the body of the adaptor to receive the two electrically conducting pins 55 and 57 of the plug 47. Flaps 41 and 43 act against opposite side edges of the plug 59 and 61, urging the plug 47 against the abutment surface 39.

As mentioned above, the flaps 41 and 43 are flexible and have a geometry such that they can accept and grip a variety of plugs having different profiles. Figures 8 and 10 illustrate examples of how the flaps adjust so as to conform with these different profiles. The flexibility of the flaps may be such as to allow a degree of relative movement between the plug 47 and the adaptor 1. In particular, the degree of movement may be sufficient to enable the pins 55 and 57 of the plug 47 to be disconnected from the pins of the adaptor when the body of the adaptor is closed. The flexibility of the flaps may even make it possible to completely withdraw the plug from the body of the adaptor.In order to further limit the degree of relative movement permissable between the plug and the adaptor over and above that provided by the flaps 41 and 43, a further means may be provided to prevent the flaps from flexing beyond a pre-determined point when the body of the adaptor is closed.

A preferred embodiment of such means is shown in Figures 11 and 12. An abutment 131, in the form of an 'L'shaped fillet is formed on each side of the front portion 11 of the adaptor. Part 133 of the abutment 131 serves to limit movement of the bent portions 46 and 48 of the flaps 41 and 43, towards the lower edge 17 of the adaptor 1, when the flaps are flexed to receive a plug.

The flaps 41 and 43 are spaced from an adjacent face of the front portion 11, as shown in Figure 12. Part 135 of the abutment 131 is positioned between the lower lateral edge 45 of each flap and the inner face of the front portion 11. This part 135 of the abutment 131 prevents lateral movement of the flaps when a plug is inserted. Preferably each abutment 131 is integrally formed with the front portion 11.

Alternatively or additionally, the means may include locking means to lock the flaps in the position they adopt when bearing on opposite side edges 59 and 61 of the plug 47.

Figures 13 to 15 show an example of a locking arrangement consisting of a pair of protrusions 91 and 93 which are formed on and extend from the upper inner wall 95 of the back portion 13. Referring to Figures 13 and 14, flaps 41 and 43 are shown securing a plug 47a within the body of the adaptor. The protrusions 91 and 93 are arranged so as to engage the outside edges 97 and 99 of the flaps 41 and 43 when the body of the adaptor is closed. The flaps 41 and 43 are thus locked between a respective protrusion 91 and 93 and a respective side edge 59 and 61 of the plug 47a.

Referring to figure 15 and 16, the plug 47b has a broader shoulder geometry than that of plug 47a shown in figure 13, so that the flaps 41 and 43 are forced further apart. With the flaps in this position, the protrusions 91 and 93 are arranged to fall between a respective inside edge of the flaps 41 and 43 and a respective side edge 59 and 61 of the plug 47b. In this case, the protrusions are inoperative as locking means. However the shoulder geometry of the plug 47b shown in figure 15 is such that when the plug is in position within the body of the adaptor, the side edges 59 and 61 of the plug 47b are either positioned very close to, or abut at least part of an inner face of the aperture 15, thereby preventing any significant relative movement between the plug and the adaptor.The sides 101, 102 of protrusion 91 and 103 and 104 of protrusion 93 may be tapered as shown in figures 14 and 16, in order to help guide the protrusions into engagement with the flaps 41 and 43 on closing the back portion 13.

An alternative locking means may comprise a plurality of protrusions formed in a pair of arrays as shown in figure 17. Each array 67 and 69 is arranged such that the protrusions sit either side of a respective flap 41 and 43, irrespective of the position that the plug profile causes the flaps 41 and 43 to adopt. Hence when the body of the adaptor is closed, the protrusions will hold the flaps in a fixed position and prevent relative movement between the plug and the adaptor. Such an arrangement effectively stiffens the flaps. The protrusions may be of any suitable shape and arranged in any suitable array, and each array may comprise a one dimensional array of teeth, such as a rachet. Preferably, these flaps are effectively stiffened or locked in position when the body of the adaptor is closed.

The following is a description of an arrangement for securing the front and back portions of a connecting device, whether the connecting device is adapted for use as an electric plug or as an electric plug adaptor.

Figures 18 and 19 show a cross-sectional view of an arrangement for securing the front and back portions 11 and 13 of a connecting device together, in accordance with an embodiment of a third aspect of the present invention.

In the example shown, the front portion comprises a channel 71 to receive a screw 73 which can be screwed into the back portion 13 to secure the two portions together when the body 3 of the device 1 is closed. The screw 73 has a head 75 which in use is accessible from the front face 25 of the device 1, and a threaded portion 77 which is connected to the head 75 by means of a shaft 79. The diameter of the shaft 79 is less than the diameter of the threaded portion 77. The channel 71 has a central chamber 81, whose internal walls are smooth and unthreaded, and a respective restricted portion 83 and 85 on each side of the chamber 81. The restricted portions 83 and 85 may be for example, threaded or alternatively, sufficiently resilient to permit self-tapping by the screw 73.The threaded portion 77 of the screw 73 and the central chamber 81 of the channel 71 are sized so that the threaded portion 77 can be received freely in the central chamber 81 when the screw 73 is unscrewed to open the body. When the threaded portion 77 is completely located within the central chamber 81, the restricted portions 83 and 85 prevent substantial inwards or outwards movement of the screw 73 unless the screw is turned. In this position, as shown in Figure 15, the head of the screw 75 and part of the shaft 79 extend beyond the front face 25 of the front portion 11 of the device 1. Preferably, the head of the screw protrudes sufficiently far beyond the front face 25 of the device 1 to prevent electrical connection between the pins of the device and the terminals of the socket.Thus, the connecting device will be prevented from carrying electricity if an attempt is made to plug the device into a socket with the back portion 13 opened, unless the screw has been screwed back up inside the device.

To open the body of the device, the screw is unscrewed sufficiently to release the back portion 13 from the front portion 11. At the point of release, the head 75 of the screw 73 may extend sufficiently far beyond the front face 25 of the device 1 so as to prevent electrical connection between the pins of the device and the terminals of the socket. Continuing to unscrew the screw, the threaded portion of the screw will eventually be completely located within the central chamber 81. In this position the threaded portion will be completely disengaged from the restricted portions 83 and 85. Thus, the screw will be held captive in this position unless the threaded portion 77 of the screw 73 is forced to engage with either of the restrictions 83 or 85, and then subsequently turned. Thus, in normal use the screw will unscrew as far as the central chamber but once the threaded portion is within the central chamber, the screw will unscrew no further.

A recess 87 is provided in the front face of the connecting device to accommodate the head 75 of the screw when the screw is screwed up inside the body of the device.

In Figures 18 and 19, the front and back portions 11 and 13 of the body 3 of the device 1 are shown as being completely separable when the body of the device is opened. In an alternative embodiment the front and back portions may be hinged together as for example shown in Figures 3 and 4.

One possible location for a fuse 63 and fuse holder 65 is shown in figures 8 and 10. The fuse and fuse holder may be withdrawn from the front face 25 of the front portion of the body of the connecting device as required by certain regulatory bodies.

Although the connecting device as used as an electric plug adaptor has been described for use with a two pin continental-style plug, it is contemplated that the device may be used to enable a plug of any standard to be connected with the terminals of a receptacle of any standard.

Claims

1. A connecting device enabling the power cable of an appliance to be connected with an electrical power receptacle by means of the device and comprising a body with pins designed for reception in said receptacle, the body of the device being adapted to enclose connection means for connecting the power cable as required to the pins of the device, wherein the body comprises front and back portions which are hinged together to permit the body to be opened for access to said connection means, the axis of the hinge being spaced from a peripheral edge of the device and adjacent to the front face thereof and the back portion having a part extending between the hinge and said peripheral edge, whereby said part protrudes beyond said front face when the portions are opened.

2. A connecting device as claimed in Claim 1 wherein said part protrudes sufficiently far beyond said front face when the portions are opened to prevent electrical connection between the pins of the device and the terminals of said receptacle.

3. A connecting device as claimed in Claims 1 or 2 wherein said hinge comprises a stub integrally formed with said front portion and extending along said axis, and a complementary recess formed in said part for accommodating said stub.

4. A connecting device as claimed in Claims 1 or 2 wherein said hinge comprises a stub integrally formed with said part and extending along the hinge axis, and a complementary recess formed in said front portion for accommodating said stub.

5. A connecting device as claimed in Claim 3 or 4 including means to urge, in a direction generally along the hinge axis, said part and said front portion together to retain said stub engaged in said recess.

6. A connecting device as claimed in Claim 5 wherein said means to urge comprises an abutment slidably engaging a face of said part normal to said axis.

7. A connecting device as claimed in Claim 6 wherein said face engaged by the abutment is spaced from the hinge axis.

8. A connecting device as claimed in any of Claim 6 or 7 wherein the part is formed as plate, such that the back and front portions of the body can be formed separately and connected together by forcing the plate between the front portion and the abutment, distorting the plate until the stub and recess snap into engagement.

9. A connecting device as claimed in any of Claims 5 to 8 wherein said part comprises two spaced parallel plates having or engaging respective oppositely directed stubs.

10. A connecting device as claimed in any preceding claim wherein the peripheral edge is an upper edge of said device opposite to the lower edge containing an entry port for the power cable.

11. A connecting device as claimed in any preceding claim designed for reception in a British standard 13 Amp socket.

12. A connecting device as claimed in any preceding claim wherein the device comprises an electric plug and said connection means enables an electric cable of said appliance to be connected to the pins.

13. A connecting device as claimed in any of Claims 1 to 11 wherein the device comprises an electric plug adaptor enabling a plug of one standard to be connected by means of the adaptor with the terminals of a receptacle of a different standard, wherein the body is adapted to enclose said plug with the pins of the plug connected as required to the pins of the adaptor.

14. A connecting device as claimed in Claim 13 wherein said body includes an abutment surface to support a front face of the plug, and a pair of opposed resilient flaps each secured at one end and arranged to bear on opposite side edges of the plug to urge the plug against said abutment surface.

15. A connecting device as claimed in Claim 14 including means to prevent further flexing of said flaps when the body of the adaptor is closed.

16. A connecting device as claimed in Claim 15 wherein said means to prevent comprises a pair of protrusions extending from an internal face of one of said portions, a respective protrusion arranged to engage a respective said flap when the body of the adaptor is closed.

17. A connecting device as claimed in any of Claims 14 to 16 wherein the free end of each of said flaps extends from said one end generally towards a lower edge of said body containing an entry port for the power cable and then bends inwardly and upwardly to engage said plug.

18. A connecting device as claimed in Claim 17 including first abutment means to limit movement of the bent portion of said flaps, when flexed, toward said lower edge of said body.

19. A connecting device as claimed in any of Claims 14 to 18 wherein a lateral edge of each of said flaps is spaced from an adjacent face of said front portion and second abutment means is provided to engage said lateral edge to prevent lateral movement of the flap on insertion of a plug.

20. A connecting device as claimed in Claim 19 including first abutment means, wherein said first abutment means and said second abutment means are formed together as an L shaped fillet.

21. A connecting device as claimed in any preceding claim wherein the body of the device further comprises a screw, the front portion having a channel to receive the screw, which screw can be screwed into the back portion for securing the two portions together to close the body, the screw having a head accessible in use from a front face of the device, a threaded portion connected to the head by a shaft of diameter less than said threaded portion, wherein said channel includes a central chamber and a respective restricted portion on each side of the chamber whereby the threaded portion of the screw can be received freely in the central chamber when unscrewed to open the body so that the head of the screw extends beyond said front face of the device, the restricted portions then preventing substantial inwards or outwards movement of the screw without turning the screw.

22. A connecting device as claimed in Claim 21, wherein the head of the screw protrudes sufficiently far beyond said front face when the threaded portion of the screw is completely located within said central chamber to prevent electrical connection between the pins of the device and the terminals of said receptacle.

23. A connecting device as hereinbefore described with reference to and illustrated by any one of the drawings.

24. An electric plug adaptor enabling a plug of one standard to be connected by means of the adaptor with the terminals of a receptacle of a different standard, and comprising a body with pins designed for reception in said receptacle, the body being adapted to enclose said plug with the pins of the plug connected as required to the pins of the adaptor, and wherein the body comprises two cooperating portions which enable the body to be opened to insert the plug and the body includes an abutment surface to support a front face of the plug, and a pair of opposed resilient flaps each secured at one end and arranged to bear on opposite side edges of the plug to urge the plug against said abutment surface.

25. An electric plug adaptor as claimed in Claim 24 including means to prevent further flexing of said flaps when the body of the adaptor is closed.

26. An electric plug adaptor as claimed in claim 25 wherein the said means to prevent comprises a pair of protrusions extending from an internal face of one of said portions, a respective protrusion arranged to engage a respective said flap when the body of the adaptor is closed.

27. An electric plug adaptor as claimed in any of Claims 24 to 26 wherein the free end of each of said flaps extends from said one end generally towards a lower edge of said body containing an entry port for the power cable and then bends inwardly and upwardly to engage said plug.

28. An electric plug adaptor as claimed Claim 27 including first abutment means to limit movement of the bent portion of said flaps, when flexed, toward said lower edge of said body.

29. An electric plug adaptor as claimed in any of Claims 24 to 28 wherein a lateral edge of each of said flaps is spaced from an adjacent face of said front portion and second abutment means is provided to engage said lateral edge to prevent lateral movement of the flap on insertion of a plug.

30. An electrical plug adaptor as claimed in Claim 29 including first abutment means, wherein said first abutment means and said second abutment means are formed together as an L' shaped fillet.

31. An electric plug adaptor as claimed in any of Claims 24 to 30 wherein the body of the adaptor comprises a front portion and a back portion.

32. An electric plug adaptor as hereinbefore described with reference to and illustrated by any one of the drawings.

33. A connecting device enabling the power cable of an appliance to be connected with an electrical power receptacle by means of the device and comprising a body with pins designed for reception in said receptacle the body of the device being adapted to enclose connection means for connecting the power cable as required to the pins of the device, wherein the body comprises front and back portions which enable the body to be opened for access to said connection means, and a screw, the front portion having a channel to receive the screw, which screw can be screwed into the back portion for securing the two portions together to close the body, the screw having a head accessible in use, from a front face of the device and a threaded portion connected to the head by a shaft of diameter less than said threaded portion, wherein said channel includes a central chamber and a respective restricted portion on each side of the chamber whereby the threaded portion of the screw can be received freely in the central chamber when unscrewed to open the body so that the head of the screw extends beyond the front face of the device, the restricted portions then preventing substantial inwards or outwards movement of the screw without turning the screw.

34. A connecting device as claimed in claim 33 wherein the device comprises an electric plug and said connection means enables an electric cable of said appliance to be connected to the pins.

35. A connecting device as claimed in 33 wherein the device comprises an electric plug adaptor enabling a plug of one standard to be connected by means of the adaptor with the terminals of a receptacle of a different standard, wherein the body is adapted to enclose said plug with the pins of the plug connected as required to the pins of the adaptor.

36. A connecting device as claimed in any of Claims 33 to 35, wherein the head of the screw protrudes sufficiently far beyond said front face when the threaded portion of the screw is completely located within said central chamber to prevent electrical connection between the pins of the device and the terminals of said receptacle.

37. A connecting device as hereinbefore described with reference to, and illustrated by any one of the drawings.