GB2276044A

GB2276044A - Coupling a flexible cord to a 3-pin plug

Info

Publication number: GB2276044A
Application number: GB9305108A
Authority: GB
Inventors: Hong An Lin
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-03-12
Filing date: 1993-03-12
Publication date: 1994-09-14
Also published as: GB9305108D0

Abstract

The present invention describes an improvement to the standard 3-pin plug where the free end of a flexible cord can be coupled to it quickly without using a wire stripper. A plurality of leads 54, 56, 58 are disposed within the interior of the plug base 42. Each of the leads has an edge terminating in a plurality of saw tooth blades for perforating through the insulation of wires. The blades are exposed within a plurality of channels, while the other edge of the lead is embedded in the plug base. The channels are formed by a plurality of ridges disposed in the plug base 42. Preferably, the ridges are parallel to each other such that straight and narrow channels can be formed when the cover and the base are closed. In use, a person places the wires of the free end of a flexible cord within the channels in the base of present invention, closes the cover and the base, and connects the plug to a socket. <IMAGE>

Description

A METHOD AND APPARATUS FOR COUPLING A FLEXIBLE CORD TO A 3 PIN PLUG The present invention pertains to the field of connectors, and in particular, the present invention concerns an improvement to the standard 3pin plug.

A 3-pin plug is a standard device for connecting an electrical equipment to a power source. By 3-pin plug, the present invention refers to British Standard BS 1363 covering 30-Amp 3-pin plugs and other similar connectors for coupling a free end of a flexible cord to a plug. With respect to 3-pin plug, the flexible cable consists of three insulated wires - Live (L), neutral (N) and earth (E). To connect the free end of a flexible cable to a 3pin plug, a person generally follows the following steps: (1) remove the cover from the base by unscrewing the plug screw, (2) strip one end of the cable such that the E wire is about 3 cm long and the L and N wires 2 cm long, (3) strip each wire to expose about 5 mm of the metal or copper wire, (4) unscrew the cord grip, (5) insert the free end of wire into the respective terminal of the pins and secure by tightening the respective screw attached to the terminal, (6) screw on the cord grip and (7) close the cover.

As one could see, connecting a flexible cable to a 3-pin plug is time consuming and fraught with difficulties. Stripping the wires to the correct length requires experience. Electricians and power professionals use a wire-stripper to overcome this problem. It can be appreciated that securing the wires to the terminals of the respective pins is a tedious process for the average person. As such, the reliability of the connection depends on the skill of the user.

The present invention describes an improvement to the standard 3-pin plug where the free end of a flexible cord can be coupled to it quickly without using a wire stripper. The present invention provides a connector for electrically coupling one end of a flexible cable having a plurality of individually insulated flexible conductors therein to an electrical supply socket, said connector having a plurality of substantially rigid pin members for insertion into said electrical supply socket and a plurality of lead members, there being at least one lead member for each pin member, each of said lead members being mounted in said connector and being connected at one end to one of said pin members and having one or more projections for piercing the insulation surrounding a conductor and for forming an electrical contact with the conductor within the insulation.

In a preferred embodiment a plurality of leads are disposed within the interior of the plug base. Each of the leads has an edge terminating in a plurality of saw tooth blades for perforating through the insulation wires. The blades are exposed within a plurality of channels, while the other edge of the lead is embedded in the plug base. The channels are formed by a plurality of ridges disposed on one hand in the plug base and on the other hand in the cover for guiding the wire of the free end of the flexible cord. Preferably, the ridges are parallel to each other such that straight and narrow channels can be formed when the cover and the base are closed. In the preferred embodiment of the present invention, a person places the wires of the free end of a flexible cord within the channels in the base of the present invention, closes the cover and the base, and connects the plug to a socket. There is no need for a wire-stripper and the reliability of connection is enhanced.

Fig. 1 illustrates a perspective elevational view of a 3-pin plug being coupled to a socket adaptor.

Fig. 2 shows a perspective elevational view of the interior of a base of a 3pin plug as illustrated in Fig. 1.

Fig.3 shows a preferred shearing of the wires of a flexible cord that is suitable for coupling to the base of a 3-pin plug as shown in Fig. 2.

Fig. 4 illustrates a top plan elevational view of the present invention.

Fig 5 is a perspective elevational view of the neutral lead of the present invention.

Fig 6 is a perspective elevational view of the earth lead of the present invention.

Fig 7 is a perspective elevational view of the live lead of the present invention.

Fig. 8 is a cross-sectional elevational view of the plug base of the present invention in accordance to Section X-X in Fig. 4.

Fig. 9 is a top plan elevational view of the plug cover and the plug base of the present invention.

Fig. 10 is a cross-sectional elevational view of the plug base and the cover of the present invention in accordance to Section Y-Y in Fig. 9.

Fig. 1 shows a perspective elevational view of a 3-pin plug 10 being coupled to a socket adaptor 20. The socket adaptor 20 provides a source of power to electrical equipment (not shown) over a flexible cord 15 which is coupled to the plug 10. It should be understood by one skilled in the art that the present invention is equally applicable to plug other than 3-pin plug.

Furthermore, the socket adaptor 20 can comply with standards other than British Standard BS 1363. Most importantly, the source of power could be either 110 AC, 220 AC or other sources.

Fig. 2 illustrates a perspective elevational view of the interior of a base 22 of a 3-pin plug 10 as illustrated in Fig. 1. The prior art plug 10 comprises an E pin 24, N pin 26 and L pin 28. Optionally, the plug 10 incorporates a fuse 30. Most plugs also feature a cord grip 32 which is used to prevent the flexible cord 15 from being yanked from the plug 10. The cord grip 32 requires the user to screw and unscrew bolts 33. Referring again to Fig. 2, the pins has a terminal 34, 36 and 38 respectively where the exposed metal wires 17, 19, and 21 is inserted into a traversing hole and subsequently secured by tightening a screw.

Fig. 3 shows a preferred shearing of the wires 17, 19 and 21 of a flexible cord 15 that is suitable for coupling to the base of a 3-pin plug as shown in Fig. 2. As described in sections above, the user has to strip the wires 17, 19 and 21 to a specific length before the reliability of the connection is ensured.

Fig. 4 illustrates a top plan elevational view of the present invention.

The new plug 40 has a plug base 42 incorporating a plurality of ridges 41.

The significance of the ridges shall be elaborated further below. Just as the prior art plug 10 in Fig. 1, the new plug 40 has E pin 44, N pin 46 and L pin 48. However, the pins does not terminated in a section incorporating a traversing hole and screw. Preferably, the pins 44, 46 and 48 comprise of solid metal blocks. This would lower the cost of manufacture as no further machining or processing of the pins is required. It should be understood by one skilled in the art that prior art pins may also be used. Optionally, a fuse 50 can be incorporated into the new plug 40. As a further option, the compartment for the cord grip may also be incorporated. Most importantly, there are now three leads 54, 56 and 58 connecting the wires with the pins 44, 46 and 48.

Fig. 5 is a perspective elevational view of the N lead of the present invention. Fig. 6 is a perspective elevational view of the E lead of the present invention. Fig. 7 is a perspective elevational view of the L lead of the present invention. Each lead has an U section for providing the interface between the pin and the lead. The U section is extended longitudinally. The longitudinal sectional has two edges. The top edge is exposed above the surface of the base 42 and the lower edge embedded in the base. The top edge terminates in a plurality of saw tooth blades 60 for perforating the wires without requiring the user to strip the insulation of the wires. The blades 60 serves a second function: they grip the wires within the channels 43 and hence obviating the need for the cord grip.

Fig. 8 is a cross-sectional elevational view of the plug base 40 of the present invention in accordance to Section X-X-- in Fig. 4. Shown in the figure are N lead 56, E lead 54 and L lead 58 being embedded in the base 40. The saw tooth blades section 60 of the leads are exposed in the lead channels 43. The height of the blades 60 corresponds approximately to the diameter of a wires 17, 19 and 21. The channels 43 are formed with the walls of ridges 41 which is incorporated in the base 40. The ridges 41 are substantially vertical and spaced such that they are at a distance which is approximately the same as the outer diameter of the wires 17, 19 and 21. It should be understood by one skilled in the art that the ridges are advantageously arranged in a parallel fashion such that the user can just lay the wires 17, 19 and 21 into the channels 43 without having to strip and expose the wires individually.

Fig. 9 is a top plan elevational view of the plug base 40 and plug cover 70 of the present invention. The cover 70 incorporates a plurality of ridges 71 which fit snugly over the channels 43 in the plug base 40. Fig. 10 is a cross-sectional elevational view of the plug base 40 and the plug cover 70 of the present invention in accordance with Section Y-Y in Fig. 9. The base 40 is shown closed with the cover 70. The ridges 72 of the cover 70 encase the wires 17, 19 and 21 into the channels 43. It follows the new plug 40 of the present invention allows the user to couple wires of a flexible cable to a plug by simply a place and snap approach.

While the present invention has been described particularly with reference to FIGS. 1 to 10 with emphasis on a method and apparatus for coupling a flexible cord to a 3-pin plug, it should be understood that the figures are for illustration only and should not be taken a limitation on the invention. In addition, it is clear that the method and apparatus of the present invention has utility in many applications where the coupling of one end of flexible cord to another is required. It is contemplated that many changes and modifications may be made by one of ordinary skill in the art without departing from the spirit and the scope of the invention as described.

Claims

1. A connector for electrically coupling one end of a flexible cable having a plurality of individually insulated flexible conductors therein to an electrical supply socket, said connector having a plurality of substantially rigid pin members for insertion into said electrical supply socket and a plurality of lead members, there being at least one lead member for each pin member, each of said lead members being mounted in said connector and being connected at one end to one of said pin members and having one or more projections for piercing the insulation surrounding a conductor and for forming an electrical contact with the conductor within the insulation.

2. The connector as claimed in claim 1, wherein said lead members are located within channels, said channels being formed by ridges disposed in the interior of the connector.

3. The connector as claimed in claim 2, wherein said ridges are substantially parallel to one another.

4. The connector as claimed in either of claims 2 or 3, wherein said channels have a cross-sectional area substantially the same as that of the individually insulated flexible conductors.

5. A method of electrically coupling one end of a flexible cable having a plurality of individually insulated flexible conductors therein to an electrical supply socket by means of a connector, the method comprising mounting the one end of the flexible cable in the connector by piercing the insulation surrounding each conductor by means of one or more projections provided on corresponding lead members mounted in the connector, each lead member being in turn connected at one end to one of a plurality of substantially rigid pin members and inserting the pin members of the connector into the electrical supply socket.

6. A method as claimed in claim 5, wherein said lead members are located within channels, said channels being formed by ridges disposed in the interior of the connector.

7. A method as claimed in claim 6, wherein said ridges are substantially parallel to one another.

8. A method as claimed in either of claims 6 or 7, wherein said channels have a cross-sectional area substantially the same as that of the individually insulated flexible conductors.

9. A connector for electrically coupling one end of a flexible cable to an electrical supply socket substantially as hereinbefore described with reference to and as shown in Figures 4 to 10.

10. A method for electrically coupling one end of a flexible cable to an electrical supply socket substantially as hereinbefore described with reference to and as shown in Figures 4 to 10.