US3781756A

US3781756A - Construction plug

Info

Publication number: US3781756A
Application number: US00286736A
Authority: US
Inventors: G Kyranakis
Original assignee: Lee Raymond Organization Inc
Current assignee: Lee Raymond Organization Inc
Priority date: 1972-09-06
Filing date: 1972-09-06
Publication date: 1973-12-25
Anticipated expiration: 1990-12-25

Abstract

A male electrical plug for use in connecting the supply line of portable electrical tools and appliances to a female socket, said plug being equipped with a retractable ground prong which may be folded out of the way when the plug is mated to a female socket which does not have a female ground receptacle. The ground prong of the plug is mounted to a hinge by a rotatable pin, and is electrically connected to a short attachment wire so that in the retracted state, the ground connection of the line cord may be made by fastening said attachment wire to an external ground connection.

Description

United States Patent [1 1 Kyranakis CONSTRUCTION PLUG [75] Inventor: Gus J. Kyranakis, Levittown, NY.

[73] Assignee: Raymond Lee Organization, Inc., New York, NY. a part interest 22 Filed: Sept. 6, 1972 21 Appl. No.: 286,736

[ Dec. 25, 1973 3,219,962 11/1965 Whalen 339/14 RP Primary ExaminerMarvin A. Champion Assistant E.mminerRobert A. Hafer Attorney-Howard l. Podell [57] ABSTRACT A male electrical plug for use in connecting the supply line of portable electrical tools and appliances to a female socket, said plug being equipped with a retractable ground prong which may be folded out of the way when the plug is mated to a female socket which does not have a female ground receptacle. The ground prong of the plug is mounted to a hinge by a rotatable pin, and is electrically connected to a short attachment wire so that in the retracted state, the ground connection of the line cord may be made by fastening said attachment wire to an external ground connection.

1 Claim, 8 Drawing Figures CONSTRUCTION PLUG SUMMARY OF THE INVENTION This invention relates to an electrical male plug with a grounding prong which may be utilized with female socket regardless of whether the female socket bears a female ground receptacle.

An advantage of this invention is that the subject electrical plug may be directly utilized without the requirement of an additional adaptor socket when it is necessary to connect said plug to a female socket which does not have the third female grounding receptacle.

A further advantage of this invention is that the electrical line cord connected to the subject electrical plug may be grounded when necessary by the use of a supplementary grounding wire attached to the electrical plug, which may be readily fastened to any grounded metal object.

The subject electrical plug is fitted with the two customary parallel male prongs which are joined in the plug to the customary white and black wires used to supply the electric power to the attahced appliance. The third ground prong is fitted in the plug to a hinged base to permit the rotation of attached ground prong to either the erect mode, for use with a three receptacle female socket, or the ground prong is rotated about the axis of the hinge pin so as to line parallel to the base of the plug, and parallel to the plane separating the male plug from the female socket, where the female socket does not contain the necessary third female receptacle.

BRIEF DESCRIPTION OF THE DRAWING The objects and features of the invention may be understood with reference to the following detailed description of an illustrative embodiment of the invention, taken together with the accompanying drawing in which:

FIG. 1 is a plan view of the electrical plug viewed from the external back of the plug;

FIG. 2 is a side view of the electrical plug;

FIG. 3 is a plan view of the electrical plug viewed from the prong connection face of theplug;

FIG. 4 is a cross-section of a side view of the plug;

FIG. 5A is an end view of the hinged ground prong of the plug;

FIG. 5B is a side view of the hinged ground prong of the plug;

FIG. 6 is a plan view of the insulator shield of the plug; and

FIG. 7 is a plan view of an outline of the pattern of the ground prong base, prior to formation of the hinge ears.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now descriptively to the drawing, in which similar reference characters denote similar elements throughout the several views, FIG. 1-4 illustrate the male electrical plug 10 of this invention which may be physically fastened to an electrical line cord by means of clamps 11 which are bolted together about the line cord by means of screws 12. The line cord passes through hole 26 to be electrically connected to the three prongs l8 and of the plug 10 by means of

screws

19 and 21. The two parallel prongs 18 are customarily connected to the white and black electrical wires of the line cord which carry the electrical power to the connected appliance or tool. The green wire of the line cord is connected to the housing of the appliance and is to be connected to the ground of the electrical system by means of ground prong 20 which mates with the ground receptacle of the mating female electrical socket or plug. Where the mating female socket or plug does not have a female receptacle into which the ground prong 20 may fit, the ground prong 20 is rotated about its fastening pin 22 which is rotatably mounted to ears 23 of the prong base 25. Prong base 25 is fastened to the plug body 13 by rivet 27.

As shown in FIG. 4, and in order to permit the rotated ground prong 20 to lie flush inside of the body 13 of the plug, shaped slot 42 is cut out of the plastic insulator strip 40 which fits about the prongs. Plastic insulator strip 40 is fitted with slots 41 to fit about parallel prongs 18. As shown in FIG. 3 and 4, a grooved space 28 is also cut out of plug body 13 to permit the prong 20 to lie in the rotated state below the common plane of intersection between the plug 10 and a mating electrical socket.

In order to electrically connect the green ground wire of the line cord to the system ground when the ground prong 20 is rotated into the flush position, ground attachment wire 15 is utilized. Ground attachment wire 15 is electrically joined to the ground base 25 of the plug l0 and it is connected by means of fastening lug 16 to a metal pipe, screw or other member which is electrically connected to the system ground.

FIG. 7 illustrates the pattern of fabrication of the base member 25 which supports the rotatable prong 20. The outline 30 is the form of the external shape of a sheet 35 of metal which is cut by. lines 37- to enable the folding of the base ears 23 by bending sections 33 about dotted lines 38. Holes 32 become the mounting points for hinge pin 22, with hole 31 being threaded to mate with screw 21 and hole 39 utilized by rivet 27 in fastening the base 25 to the body 13 of the plug 10.

Since obvious changes may be made in the specific embodiment of the invention described herein, it is indicated that all matter contained herein is intended as illustrative and not as limiting in scope.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. An electrical male plug which is used to connect an attached set of electrical wires to a source of electrical supply, said plug containing prongs which fit into female receptacles of an electrical socket or female plug, with one of said prongs being pivotably mounted to a fixed base by means of a pin so as to be capable of rotation with respect to said base with the body of the plug shaped to permit said prong to lie below the exterior surface plane of the electrical plug in the rotated mode, so that said electrical plug may be joined to an electrical socket which does not have a mating female receptacle for the rotated prong,

said rotatable prong, when it is rotated into the erect position being shaped and located so as to fit into the female ground receptacle of an electrical socket or female electrical plug, to which the male electrical plug is joined, with said fixed base being fabricated ofa section of sheet metal in which two ears are formed, each bent at right angles to the plane of the sheet metal, said ears being pierced, with a metal pin fitted through the two ears and the rotatable prong furnishing the tion extending out of the plug, which clamp section protrudes past the exterior of the plug adjacent a hole in the plug through which a cable of electrical wires attached to the plug are led, with means to fasten the clamp section to the exterior of such an attached cable so as to make mechanical contact with said cable and to make an electrical ground contact with a metal closure which may be wrapped about the exterior of said cable.

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Claims

1. An electrical male plug which is used to connect an attached set of electrical wires to a source of electrical supply, said plug containing prongs which fit into female receptacles of an electrical socket or female plug, with one of said prongs being pivotably mounted to a fixed base by means of a pin so as to be capable of rotation with respect to said base with the body of the plug shaped to permit said prong to lie below the exterior surface plane of the electrical plug in the rotated mode, so that said electrical plug may be joined to an electrical socket which does not have a mating female receptacle for the rotated prong, said rotatable prong, when it is rotated into the erect position being shaped and located so as to fit into the female ground receptacle of an electrical socket or female electrical plug, to which the male electrical plug is joined, with said fixed base being fabricated of a section of sheet metal in which two ears are formed, each bent at right angles to the plane of the sheet metal, said ears being pierced, with a metal pin fitted through the two ears and the rotatable prong furnishing the mechanical and electrical connection between the rotatable prong and the fixed base, said base incorporating a threaded hole in which a screw is fastened, adaptable for connection to the ground wire of a set of electrical wires attached to the plug, said fixed base being fastened to the plug by a metal rivet which is also fastened about the conductor of a length of insulated wire extending out of the plug, and said rivet also fastened to a metal clamp section extending out of the plug, which clamp section protrudes past the exterior of the plug adjacent a hole in the plug through which a cable of electrical wires attached to the plug are led, with means to fasten the clamp section to the exterior of such an attached cable so as to make mechanical contact with said cable and to make an electrical ground contact with a metal closure which may be wrapped about the exterior of said cable.