GB2219472A - Branching adaptors on electrical connectors - Google Patents

Abstract

A main electrical connector (15) consists of a domestic plug body (16), with a shroud (21) attached on its inner side and its pins (18, 19, 20) extending beyond the shroud. A branching adaptor (25) consists of a flat body (27, 28) having apertures (55, 56) which are seated in use over the pins of the main connector to supply electrical current to additional electrical appliances. This obviates the need for additional plugs and results in a less heavy and cumbersome apparatus. The thickness of an adaptor can correspond to its current rating. <IMAGE>

Description

ELECTRICAL CONNECTORS This invention relates to electrical connectors for attachment to electrical goods and equipment and by means of which the goods and equipment can be put into communication with the electrical mains supply.

The invention relates in particular to low wattage connector devices for attachment to appliances which typically require a low electrical current supply, e.g. of up to 2 or 3 amps. Aims of the invention are to provide, firstly, an improved low power electrical connector device in the form of a plug, which can be used on its own to connect an appliance to a conventional electrical supply outlet point, in the form of a standard socket, secondly a connector device, which can be used to connect one or more further appliances to the same socket or other outlet point and, thirdly, any desired combination of an improved electrical connector device of the first kind, according to the invention, and of one or more improved electrical connector devices of the second kind, according to the invention, as a kit or assembly of parts.

The invention can readily be explained and illustrated in conjunction with conventional outlet points and plug connectors of the 3-pin 13-amp kind, such as are used where a ring mains is installed in a house or other building. However, the principle underlying the inventive concept, in which connector devices attached to additional appliances are passed on to the pins of a plug attached to a first appliance, can be readily adapted for use with any of the large range of plug and socket electrical connector devices in use nowadays in many countries, especially in domestic use. It should be noted that the invention is applicable to electrical connectors having any number of contact pins.

Since many electrical appliances require a power supply very much lower than the normal rated power supply of 13 amps, it is common practice to use various kinds of adaptor, in order to connect two or more appliances to the same socket or other outlet point. For instance, the usual 13-amp adaptor provides the facility for plugging in up to three appliances, although this has the disadvantages that the adaptor itself is bulky and heavy and the assembly of an adaptor and up to three plugs is especially bulky and heavy. Thus, while it may readily be possible to connect up to four appliances in this way to a single outlet point, the mass of the plugs in the adaptor unit conventionally required is considerable and they require a space which is of considerable size.Other schemes for using one outlet for several appliances include trailing connector bars, having a plug on a short lead attached to a box or bar incorporating up to 4 sockets. These also are very heavy and cumbersome.

Thus it is an object of the invention to overcome excessive weight and bulk in electrical connectors.

According to one aspect of the invention there is provided an electrical connector comprising at least one supported electrical connection pin and a shroud around the at least one pin for accommodating at least one auxiliary connector slidably mounted on the at least one pin for taking electricity therefrom, the at least one pin protruding from the connector.

According to another aspect of the invention there is provided an electrical connector comprising a body having at least one through-aperture extending from a first to a second side of the body for slidably receiving from the first side a connection pin of an associated electrical connector so that the pin protrudes from the second side, electrical contact means in or adjacent the or each aperture for contacting such a connection pin, and electrical communication means for electrically communicating the or each contact means with an electrical appliance. Preferred features of the invention are given in the dependent claims. A kit or assembly of the electrical connectors is also provided according to further aspects of the invention.The invention removes the need for additional plugs for additional appliances and the resulting apparatus is considerably less heavy and cumbersome than the conventional apparatus.

A preferred embodiment of this invention sets out to remedy the above disadvantages, preferably without requiring any modification whatsoever of the conventional 3-pin 13-amp or other form of standard power supply outlet point or socket, by providing an improved form of plug connector, to which an electrical appliance can be connected, which consists of a body member from which line, neutral and (if required) earth pins project in the conventional disposition, where either or each of the pins has an increased length and the part of each pin adjacent the body member is at least substantially surrounded by an insulating shroud, which thus forms a housing capable of receiving one or more auxiliary connectors attached to other appliances and arranged for electrical communication with the line, neutral and earth pins.When one or more auxiliary connectors are mounted on the plug connector, each of the appliances can be put into communication with the mains supply when the plug, with one or more of the auxiliary connectors passed over its pins and located in its shroud or housing, is inserted into a socket or other form of matching outlet.

In a preferred embodiment, there is also provided an electrical connector device to which the lead from an electrical appliance can be connected, which consists preferably of a wafer-like or otherwise flat form of body member, having line, neutral and (if required) earth contacts located within it and accessible by way of through-going holes in the thickness of the body member, which has a shape such that it can be attached to a plug connector of the aforementioned kind, by having its contact holes passed over the line, neutral and (where provided) earth pins of the plug respectively and accommodated within the shroud.

The shroud of the first type of connector device preferably includes a slot disposed parallel to the direction of the pins and capable of receiving and housing the insulated electrical leads by which appliances are attached to the second kind of connector device. Preferably, the shroud also is arranged to be capable of receiving from one up to four (or even more) similar connectors of the second type, so that up to five appliances, say, having a suitable maximum amperage within the rated amperage value of the outlet point or socket, can be connected to a single outlet point.In accordance with an especially preferred feature of the invention, less than the designed maximum number of connector devices of the second kind can be appropriately accommodated in the shroud of the connector device of the first kind by reason of the strong spring force by which the line, neutral and earth contacts of the one grip the corresponding pins of the other.

In order that the first and second kinds of electrical connector devices according to the invention and the kit or assembly of parts made from them can be more readily understood, reference is made to the accompanying drawings, in which a preferred embodiment of each of the two kinds of connector device, for use together, is shown.For ease of description and in view of their different but related principles of construction, the first kind of device is called a "plug" and the second is called a "connector." In the accompanying drawings: Fig. 1 shows a preferred form of plug of the invention in an end elevational view; Fig. 2 shows the plug of Fig. 1 in side elevational view; Fig. 3 shows an inside elevational view of the front component of a body member or wafer unit of a connector according to the invention, for use with a plug as shown in Figs. 1 and 2; Fig. 4 shows a sectional view of the component of Fig. 3 taken on the line III-III; Fig. 5 shows an inside elevational view, similar to Fig. 3, of the back component of the body member or wafer of a connector according to the invention; Fig. 6 shows a sectional view of the component of Fig. 5 taken on the line V-V; ; Figs. 7a and 7b show respectively side and plan views of a contact member, two of which are incorporated in the wafer or connector comprising one of the front components according to Figs. 3 and 4 and one of the back components according to Figs. 5 and 6 coupled together, while Figs. 8a and 8b show corresponding side and plan views of a slightly different kind of contact member, one of which is also incorporated in the wafer or connector assembly shown in more detail in Figs. 3 to 6; Fig. 9 shows the form of plug according to the invention shown in Figs. 1 and 2, in diagrammatic perspective view; Fig. 10 shows the connector according to the invention, made by assembling the components shown in rigs. 3 to 6, Figs. 7a, 7b and Figs. 8a, 8b, also in diagrammatic perspective view;; Fig. 11 shows a diagrammatic perspective view similar to Figs. 9 and 10, illustrating how up to four of the connectors according to Fig. 10 can be accommodated in the shroud of a plug according to Fig.

9; Fig. 12 shows a modified connector according to the invention; Fig. 13 shows a modified plug according to the invention for use with the connector of Fig. 12 (with the connection pins omitted for clarity); and Fig. 14 shows connectors according to the invention having different thicknesses and received in a plug according to the invention.

An electrical connector in the form of a plug is shown diagrammatically in Figs. 1, 2 and 9 at 15.

The plug 15 represents a preferred embodiment of the first kind of connector or "plug" according to the invention. The plug 15 consists of a number of electrically-insulating plastics components assembled together in conventional fashion and, to a large extent, it resembles a conventional ring main otherwise known as a domestic plug, having a body member 16, with an electrical lead, such as a 3-core insulated cable 17, attached via its lower face and a neutral pin, a line pin and an earth pin, shown respectively at 18, 19 and 20, attached to and projecting from its inner face.

In the usual way, the earth pin 20 is somewhat longer than the line and the neutral pins 19, 18, so that the earth pin 20 first enters the corresponding recess (not shown) in an electrical outlet point or socket, thus opening the insulating shields which conventionally cover the entrances to the corresponding live and neutral recesses. In the plug 15 according to the invention, the pins 18, 19 and 20 are substantially longer than is conventionally the case and the parts of them nearer the body member 16 are surrounded by an integral wall or shroud 21, which projects from the inside face of the body member 16.The body member 16 is typically of square or rectangular shape, as best shown in Fig. 1 while the shroud 21 encloses a space of trapezoidal shape, also as best shown in Fig. 1, and preferably it completely surrounds this space, except for a slot 22, which can conveniently be provided along the top centre line of the plug 15 and which serves, as explained in more detail below, to allow electrical cables to emerge from the shroud 21. By making the shroud 21 of trapezoidal shape and accommodating it within the rectangular shape of the body member 16, two triangular upper shoulders 23 are formed, which facilitate gripping the plug 15 with the fingers, for instance when it is to be withdrawn from an electrical outlet point.

The plug 15 according to the invention, shown in elevation and side view in Figs. 1 and 2 and in diagrammatic perspective view in Fig. 9, although modified in order to accommodate one or more auxiliary connectors for operating two or more appliances from the same socket, is fully usable on its own in any conventional socket, in order to supply electrical power to whatever appliance is attached via the cable 17 to the plug 15. When inserted into a socket by means of the end parts of the pins 18, 19 and 20, the plug 15 can be pushed in to the socket until the face of the socket is contacted by the rim of the wall or shroud 21.

Referring to Figs. 3 to 6 inclusive, the back and front components of a second type of electrical component, in this case a "connector", , according to the invention, are shown, for use as described below with the first type of electrical connector. This connector is also illustrated in perspective view in Fig. 10 and takes the form of a flat housing or connector 25 to which a cable 26 can be attached, the other end of which is connected to an electrical appliance which is to be connected to the mains supply by means of the connector 25 and its associated plug 15.

The connector 25 comprises a generally flat wafer-like housing of about 1/2 cm thickness, consisting of a front part 27 and a co-operating rear part 28, which are fitted together and secured to one another, for instance by means of screws or screw-bolts and nuts (not shown). The front part 27 is illustrated in more detail in elevation in Fig. 3 and in sectional view on the line III-III in Fig. 4. It consists of a moulding 29, preferably a one-piece moulding of electrically-insulating plastics material, having a generally trapezoidal shape and formed from a flat body plate 30 having a peripheral wall 31. The wall 31 and therefore the overall shape of the front part 27 is designed to be a close fit within the similarly shaped shroud 21 of the plug 15.

At the centre top of the front part 27, the wall 31 is interrupted by means of an aperture 32 through which is led the cable 26 attached to the connector 25, as shown in Fig. 10. On its inside surface, the plate 30 includes four raised bosses, one 33a, located near the top on each side of the aperture 32 and one, 33b, located in each lower corner adjacent the wall 31. Between the bosses 33a at the top, an integral rib 34 is provided, forming part of a clamping arrangement for the cable 26 as will be explained further below. Each boss 33a includes a central aperture 35, by which self-tapping screws or set screws with associated nuts or other detachable connecting means are used to secure the front part 27 to the rear part 28 in order to form the connector 25.

Each lower boss 33b has a rectangular aperture 35' associated with it on the inboard side, for receiving the neutral pin 18 and the line pin 19 respectively of a plug 15, while a similar rectangular aperture 36 is provided centrally of the plate 30, for receiving the earth pin 20.

Referring to Figs. 7a, 7b and 8a, 8b, each lower boss 33b adjacent an aperture 35 forms the means for supporting an electrical contact member 37 (Figs.

7a, 7b), which comprises a tubular metal block 38 attached to the arcuate or curved part of a hairpinlike metal spring 39, typically made of phosphor bronze and having an opposed pair of spring legs 40, which as clearly shown in Fig. 3 overlie the associated aperture 35. Similarly, a central boss 41 is provided adjacent the earth pin aperture 36 and a similar contact unit 42 (Figs. 8a, 8b), comprising a metal block 43 and a hairpin-shaped spring 44, is provided, including an opposed pair of spring legs 45 which again, as shown in Fig. 3, overlie the associated aperture 36.

With reference now to Figs. 5 and 6, the rear part 28 of the connector 25 also consists of a preferably one-piece electrically-insulatLng plastics moulding, of the same trapezoidal shape as the front part and comprising a body plate 46 having R peripheral wall 47 which is rebated on the outside near its rim 48, so as to provide a wall part 49 of reduced thickness and a shoulder 50. It will be readily appreciated that when the front and rear parts 27 and 28 are fitted together, the wall 31 of the front part 27 fits outside the reduced thickness wall part 49 and abuts the shoulder 50 of the wall 47. The closed housing of the connector 25 is indicated by the illustration of the position of the front part 27 in association with the front part 28, the front part 27 being shown in broken lines in Fig. 6.At the corresponding position at the top of the rear part 28, the wall 47 is interrupted by means of an aperture 51 which co-operates with the aperture 32 in the front part 27 in order to allow the connector 25 to be attached to the cable 26. Each side of the aperture 51, a boss 52 is moulded into the plate 46, and cooperates with the corresponding boss 33 in the moulding 29. A pair of spaced ribs 53 also extend between the bosses 51 and form a chicane for clamping the cable 26. Another pair of bosses 54 is provided, each boss being located adjacent one of the lower corners of the plate 46. The bosses 52 and 54 cooperate with the respective bosses 33 in the other part 27 and enable the two parts to be coupled together, as indicated, for instance by counter-sunk self-tapping screws or set screws with associated nuts.

The plate 46 has a pair of apertures 55, one located adjacent each of the lower bosses 54 and serving to allow the neutral pin 18 and line pin 19 of the plug 15 to pass through the connector 25 and a centrally-located aperture 56, which similarly allows the earth pin 20 to pass through the connector 25. It will of course be appreciated that the apertures 55 and 56 register with the apertures 35 and 36 of the front part when the parts 27 and 28 are fitted together.

Ribs 57 are moulded integrally on the inside of the plate 46, as shown in Fig. 5, and can include a housing 58 for receiving a fuse link for the line conduit of the cable 26. Adjacent the central aperture 56, a fifth boss 59 is also provided, for co-operation with the corresponding boss 41 on the plate 30.

In order to connect the cable 26 of an appliance to the auxiliary connector 25, the three wires of the cable 26 are separately connected to the contact members 38 and 43 respectively and then the two parts 27,28 are secured together with the end of the cable 26 clamped in the chicane structure formed between the ribs 34 and 57.The opposed pairs of legs 40 and 45 of the springs 39 and 44 respectively thus are located between the opposed pairs of apertures 35, 55 and 36, 56 so that, when the connector 25 is threaded or passed over the end of the earth pin 20 and then over the ends of the neutral and line pins 18,19 of a plug, these pins will force open the respective pairs of legs 40 and 45, which are designed then to lie substantially flat against the major side surfaces of the pins 18, 19 and 20 and thus provide good electrical communication between the appliance attached to the cable and the pins 18, 19 and 20.When the plug 15, with one or more of the connectors 25 mounted upon its pins within the shroud 21, as shown in Fig. 11, is thus assembled, there is satisfactory electrical communication between each of the appliances attached to the cables 17 and 26 and the pins 18, 19 and 20, so that the appliances can communicate with the mains supply when the plug with the connectors 25 is inserted by means of its pins 18, 19 and 20 into a conventional 3-hole mains supply outlet or socket.

In the normal method of use of the connectors 25 which is envisaged, they would be designed to accommodate a 2-amp or 3-amp fuse or fuse link in the housing 58 and would thus serve to connect to the mains supply an appliance requiring such power supply.

However, any appliance having a rating up to 10 amps can be singly attached to a wafer or connector 25, without any risk of it over-heating in use. For safe operation, it is of course necessary to ensure that the total amperage likely to be drawn by all the appliances connected to one outlet shall not exceed the rated value of 13 amps, although it can be seen that up to five appliances, each requiring 2 or 3 amps for normal operation, can be satisfactorily attached to the same outlet or socket.

A modified connector 25', shown in Fig. 12, has a locating device, e.g. a recess, Sa, in its outer edge. In assembly, the connector is pushed into the shroud of a corresponding plug so as to fit with a coacting locating device, e.g. a complementary projection, 51, which extends along the whole length of the shroud 21. This ensures that the connector can only be inserted in the shroud in its correct orientation, i.e. with the contacts of the live aperture 55a inserted over the line pin 19, rather than incorrectly over the neutral pin 18.This could alternatively be achieved by means of co-operative locating devices on the one or more pins 18, 19, 20 and their apertures 55a, 55b, 56, or by having the cables 26 and the corresponding slot 22 in a position which is not symmetrical about a longitudinal vertical plane through the earth pin 20/central aperture 56, or by having connectors 25 with their sides inclined at different angles to the aforesaid longitudinal vertical plane and a shroud on the plug with its intention correspondingly shaped.

In a further modification of the invention, connectors of different thicknesses are employed, each thickness corresponding to a different amperage so that the depth of the shroud and hence the maximum thickness received determines that the amperage which can be loaded on the plug cannot exceed the maximum permissible amperage provided by the socket to which the plug is attached. Figure 14 shows such connectors of different thicknesses, the connector being indicated by the dashed lines. Two connectors 25a, 25b are of a first thickness x, signifying 2 amp loading and the other two connectors, 25c 25d are of a greater second thickness, y, signifying 3 amp loading. The possible combinations of connector thickness/amperage determine the different appliances which can be supplied with power at the same time by the assembly.

It will be appreciated that the invention enables a plurality of appliances to be supplied with power in a very much more compact and neat way than conventional adaptors allow.

Claims (20)

CLAIMS:

1. An electrical connector comprising at least one supported electrical connection pin and a shroud around the at least one pin for accommodating at least one auxiliary connector slidably mounted on the at least one pin for taking electricity therefrom, the at least one pin protruding from the connector.

2. A connector according to claim 1 including means for permanently electrically communicating the pin with a preselected electrical appliance and a housing for such means.

3. A connector according to claim 2, including a pair of spaced shoulders by means of which the connector can be gripped manually.

4. A connector according to claim 1, 2 or 3, wherein the shroud includes a slot for accommodating a cable extending from the or each auxiliary connector to its electrical appliance.

5. A connector according to any preceding claim, having a plurality of pins arranged symmetrically about a plane and including asymmetric means to ensure the correct orientation of the or each auxiliary connector in the shroud.

6. A connector according to claim 5, wherein the asymmetric means comprise one or more of cooperative locating means on the shroud and the or each auxiliary connector, co-operative locating means on the or each pin and the or each auxiliary connector, or an asymmetrically-shaped shroud interior for receiving a complementarily-shaped auxiliary connector.

7. A connector according to claim 5 when dependent on claim 4, wherein the asymmetric means comprises the slot being disposed asymmetrically about the plane.

8. A connector according to any preceding claim, wherein the shroud is of a depth predetermined in accordance with the thickness of the or each auxiliary connector which corresponds to the loading required by the respective electrical appliance so as to ensure that the amperage which can be loaded onto the connector cannot exceed a maximum permissible amperage.

9. An electrical connector comprising a body having at least one through-aperture extending from a first to a second side of the body for slidably receiving from the first side a connection pin of an associated electrical connection pin of an associated electrical connector so that the pin protrudes from the second side, electrical contact means in or adjacent the or each aperture for contacting such a connection pin, and electrical communications means for electrically communicating the or each contact means with an electrical appliance.

10. A connector according to claim 9, wherein the first and second sides of the body are parallel, planar major faces of the body.

11. A connector according to claim 10, wherein the first and second sides of the body are provided by respective first and second mating portions of the body.

12. A connector according to claim 9, 10 or 11, wherein the contact means comprises a resilient member disposed between the first and second electrically conductive sides of the body and across the aperture.

13. A connector according to claim 12, wherein the resilient member comprises a pair of spaced limbs biassed towards one another.

14. A connector according to claim 12 or 13, wherein the resilient member comprises a curved portion disposed around a support on the connector body, the curved portion being in electrical contact with an electrically-conductive element comprising means for connection with an electrical appliance.

15. A connector according to any of claims 9 to 14, including a cable grip comprising at least one rib on each portion of the connector body.

16. A connector according to claim 15, wherein the dable grip comprises a simple rib on one portion of the connector body disposed between a pair of spaced ribs on the other portion of the connector body.

17. A connector according to any of claims 9 to 16, wherein the connector is for use with a conventional domestic plug socket and includes a through-aperture, electrical contact means and electrical communication means corresponding to each aperture of the socket and in the same arrangement as the apertures of the socket.

18. A connector according to any preceding claim for use with an associated electrical connector according to any of claims 1 to 8.

19. An electrical connector constructed and arranged substantially as herein described with reference to Figures 1, 2, 9, 11, 13 and 14.

20. An electrical connector constructed and arranged substantially as herein described with reference to Figures 3 to 8, 10 and 12.

21 . A kit or assembly comprising an electrical connector according to any of claims 1 to 8 and an electrical connector according to any of claims 9 to 17.