GB2125233A

GB2125233A - Electrical plug and socket connection

Info

Publication number: GB2125233A
Application number: GB08222222A
Authority: GB
Inventors: William Frederick Nagel
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-08-02
Filing date: 1982-08-02
Publication date: 1984-02-29

Abstract

An electrical plug (Figures 3 and 4) has connector pins 12, 13 separated from an earthing shield 14 by solid insulation 10. The plug connects to a socket (Figures 1 and 2) having contacts 2-4 which may be spring loaded. The shutter entry aperture may be closed by spring- biassed shutter 6 lockable by a latch and detent 7 and incorrect insertion of the plug prevent by grooves 16. Detent 7 also engages a groove 15 in the earth shield to form a plug lock. <IMAGE>

Description

SPECIFICATION Safety electrical power plugs and sockets Technical field of application Electrical power industry Background art a) Electrical plug and socket insulation It is common practice to use mainly air space as the main electrical insulation between connecting pins of electrical plugs and sockets, this has the disadvantage that the electrical strength of air is relatively low and this is reflected in the wide pin pitch constructions in use today.

b) Electrical power isolation Isolation of electrical plugs is normally performed by switches on the socket. This has the disadvantage that the socket pitch has to be enlarged for multi-socket installations.

c) Accidental plug removal Conventional plugs often work loose after some period in service, the result is that accidental plug removal can occur when the plug is used with moveable electrical apparatus.

d) Safety Although current electrical sockets include a shutter covering the live sockets, this is often flimsy, and can be easily broken leaving a potential dangerous situation.

Solution of the technical problems a) Plug and socket insulation The invention uses mainly solid insulation between conducting pins and earth shield to increase the Electrical strength of the arrangement of plugs and sockets. This configuration permits much closer pin spacings without sacrifice to the electrical insulation properties of the plug and socket. Obviously at the interface of the connections solid insulation cannot be installed and this factor limits the pin spacing useable in practice.

b) Electrical power isolation By adopting a switch mounted on the plug instead of the socket no increase in socket pitch is required on multi-plug installations.

c) Plug locking By adopting a spring loaded detent on the plug, accidental plug removal is made more likely.

d) Safety The invention includes substantial safety shutters which can be designed to resist forces in excess of human strength. An additional safety feature of the invention is the use of an earth shield which prevents access to the live electrical pins.

Drawings Figure 1General arrangement of socket The socket 1 comprises a flanged high Electrical Strength moulding with 3 electrical pins 2, 3 and 4 which can be moulded in. The socket 1 may be circular at the rear but any geometric form can be used and may comprise of more than one moulding. The pin terminals contain electrical cable connection facilities, the pins may include springs 5 to enhance the contact forces. Shutters 6 prevent entry by objects when the plug is not inserted. The shutters are locked by a latch and detent 7 which is forced upwards by the spring 8.

The shutters 6 are forced to close by torsion springs 9.

Figure 2-Section through socket The section shows the plug entry cavity to be rectangular, and the arrangement of pins 2, 3 and 4, many other geometric arrangements are possible.

Figure 3-General arrangement of plug The plug assembly comprises high Electrical Strength mouldings, the base moulding 10 has socket conforming pins 12 and 13 and an earth shield 14 which have provisions for connecting the electrical leads and fuse, if fitted. Base moulding 10 may comprise several mouldings.

The cap moulding 11 is shown attached to the base moulding 10 by a screw. The earth shield contains a groove 1 5 which engages with detent 7 to form a plug lock. The earth shield also includes grooves 16 which engage with conforming pips at the plug entry point of socket moulding 1, this arrangement prevents incorrect plug insertion.

Figure cross section through plug This section shows the conforming pin arrangement and the earth shield, many geometric forms are possible. Also shown are the grooves 1 6 preventing incorrect plug entry.

Figure 5-Detail of detent Detail of the detent 7 and 8.

Best mode The best mode of application envisaged is the use of the invention in industry and homes when it is required to disconnect/connect an electrical apparatus from/to a source of electrical power.

Exploitation and manufacture in industry The invention can be designed to: a) Reduce manufacturing costs of electrical plugs and sockets.

b) Reduce the cost of installing electrical sockets.

The method of manufacture envisaged is to construct plugs and sockets in insulating mouldings and the electrical conducting parts from metal.

Claims

1. An electrical plug and socket arrangement whereby the main insulation between connecting pins and earth shield is by means of substantially

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Safety electrical power plugs and sockets Technical field of application Electrical power industry Background art a) Electrical plug and socket insulation It is common practice to use mainly air space as the main electrical insulation between connecting pins of electrical plugs and sockets, this has the disadvantage that the electrical strength of air is relatively low and this is reflected in the wide pin pitch constructions in use today. b) Electrical power isolation Isolation of electrical plugs is normally performed by switches on the socket. This has the disadvantage that the socket pitch has to be enlarged for multi-socket installations. c) Accidental plug removal Conventional plugs often work loose after some period in service, the result is that accidental plug removal can occur when the plug is used with moveable electrical apparatus. d) Safety Although current electrical sockets include a shutter covering the live sockets, this is often flimsy, and can be easily broken leaving a potential dangerous situation. Solution of the technical problems a) Plug and socket insulation The invention uses mainly solid insulation between conducting pins and earth shield to increase the Electrical strength of the arrangement of plugs and sockets. This configuration permits much closer pin spacings without sacrifice to the electrical insulation properties of the plug and socket. Obviously at the interface of the connections solid insulation cannot be installed and this factor limits the pin spacing useable in practice. b) Electrical power isolation By adopting a switch mounted on the plug instead of the socket no increase in socket pitch is required on multi-plug installations. c) Plug locking By adopting a spring loaded detent on the plug, accidental plug removal is made more likely. d) Safety The invention includes substantial safety shutters which can be designed to resist forces in excess of human strength. An additional safety feature of the invention is the use of an earth shield which prevents access to the live electrical pins. Drawings Figure 1General arrangement of socket The socket 1 comprises a flanged high Electrical Strength moulding with 3 electrical pins 2, 3 and 4 which can be moulded in. The socket 1 may be circular at the rear but any geometric form can be used and may comprise of more than one moulding. The pin terminals contain electrical cable connection facilities, the pins may include springs 5 to enhance the contact forces. Shutters 6 prevent entry by objects when the plug is not inserted. The shutters are locked by a latch and detent 7 which is forced upwards by the spring 8. The shutters 6 are forced to close by torsion springs 9. Figure 2-Section through socket The section shows the plug entry cavity to be rectangular, and the arrangement of pins 2, 3 and 4, many other geometric arrangements are possible. Figure 3-General arrangement of plug The plug assembly comprises high Electrical Strength mouldings, the base moulding 10 has socket conforming pins 12 and 13 and an earth shield 14 which have provisions for connecting the electrical leads and fuse, if fitted. Base moulding 10 may comprise several mouldings. The cap moulding 11 is shown attached to the base moulding 10 by a screw. The earth shield contains a groove 1 5 which engages with detent 7 to form a plug lock. The earth shield also includes grooves 16 which engage with conforming pips at the plug entry point of socket moulding 1, this arrangement prevents incorrect plug insertion. Figure cross section through plug This section shows the conforming pin arrangement and the earth shield, many geometric forms are possible. Also shown are the grooves 1 6 preventing incorrect plug entry. Figure 5-Detail of detent Detail of the detent 7 and 8. Best mode The best mode of application envisaged is the use of the invention in industry and homes when it is required to disconnect/connect an electrical apparatus from/to a source of electrical power. Exploitation and manufacture in industry The invention can be designed to: a) Reduce manufacturing costs of electrical plugs and sockets. b) Reduce the cost of installing electrical sockets. The method of manufacture envisaged is to construct plugs and sockets in insulating mouldings and the electrical conducting parts from metal. Claims

1. An electrical plug and socket arrangement whereby the main insulation between connecting pins and earth shield is by means of substantially solid insulating material rather than mainly air space.

2. An electrical plug and socket as described in claim 1 containing.

a) Moulded in termination pins as generally shown in figures 1, 2, 3 and 4.

b) Sprung termination pins to increase contact pressure.

c) Spring loaded shutters preventing socket access, with locking devices, when the plug is removed.

d) A spring loaded detent preventing accidental plug removal.

e) An electrical plug cap which contains provision for attaching the connecting leads.

f) An electrical plug which incorporates an electrical isolating switch.

g) An interlocking device for preventing the plug being dismantled.

h) An electrical socket with a substantially circular rear portion to fit into a substantially circular cavity.

i) An electrical socket with any geometric form of socket rear portion.

j) A plug with facilities to prevent incorrect plug insertion.

3. A multi-socket arrangement of sockets as described in claim 1 mounted on a common moulding.

4. A multi-socket arrangement as described in claim 3 with moulded in connecting leads between the individual sockets.