US3171703A - Power plug - Google Patents

Description

March 2, 1965 E. J. ALBERTS POWER PLUG Filed July 9, 1962 IN V EN TOR. EDWARD 4L BERKS ATTORNEYS electrically energized blade terminals.

United States Patent and This invention relates generally to a new and improved electrical connector, and more particularly to a unique and highly advantageous construction for a male electrical power plug of the type used with an electrical appliance or the like.

The usual electrical connector power plug of the subject type comprises a body of insulating material having a central aperture for receiving a conductor cord and two or more blade terminals connected to the cord conductors. The blade terminals normally are supported by and project outwardly from the plug body for engagement with the contacts of a receptacle or other power outlet with which the plug is to be used. Conventionally, the plug body may be formed of a relatively resilient, unbreakable material although a large number of power plugs are in use of the so-called hard body or breakable type.

It will be appreciated that much care is required in the use of such an electrical power plug to lessen the possibility of electrical shock when the plug is inserted into a power outlet. Instances are known wherein the fingers have moved or slipped on the power plug body as the latter is being inserted into an outlet with the result that the fingers are placed into accidental contact with the Also, it is possible that a power plug of the prior art may be grasped in such a way that the thumb and finger, or other parts of the hand, touch the blade members adjacent the blade end of the plug body with the result that an electrical shock hazard is present during insertion of the plug into the power outlet.

Accordingly, it is a general object of this invention to provide a new and improved electrical connector power plug construction which overcomes the shock hazard liabilities of prior art power plug constructions.

It is another object of this invention to provide a new and improved power plug construction having unique shock hazard safety means integrally formed therewith to protect the fingers from accidental contact with the energized blade members of the plug.

It is a more particular object of this invention to provide such an improved power plug construction having a plurality of transverse, co-planar flange means extending outwardly from the power plug body to provide an insulating barrier between the fingers and the terminal blades of the plug.

It is a further object of this invention to provide a new and improved power plug construction, as above, wherein the transverse, co-planar flange means are formed of resilient material so as to flex forwardly toward the blade members to protect the fingers from accidental contact with the energized blade members in the event the fingers slip forwardly on the plug during the insertion thereof into a power receptacle.

It is a still further object of this invention to provide a unique and highly advantageous power plug which is characterized by its novelty of construction and by the high degree of protection from electrical shock-hazard which it provides.

The novel features which are characteristic of the invention are set forth with particularlity in the appended claim. The invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, will best be underddllfihfi Patented Mar. 2, 1965 stood by reference to the following description taken in conjunction with the accompanying drawing in which:

FIGURE 1 is a pictorial view, partly in cross-section, illustrating the construction and operational advantages of a representative power plug embodying the present invention;

FEGURE 2 is a cross-sectional view taken substantially as shown along line 2-2 of FIGURE 1; and

FIGURE 3 is an end elevational view of the representative power plug shown in FIGURES l and 2.

Referring now to the drawing and more particularly to FIGURES l and 2 thereof, there is shown an electrical power plug and socket assembly illustrating the novel features of the present invention. The power plug 10 advantageously comprises a body portion 12 which may be formed of any suitable electrical insulation material of the type well-known in the art. Advantagcously, the plug body portion 1?. may be molded or otherwise formed of a resilient insulation material such as hard rubber, plastic, or the like. The body portion 12 is provided with an opening 14 at one end thereof for receiving an electric power cord 16 which is positioned therethrough. The electric power cord advantageously comprises a pair of electrical conductors 1.3 and 20 in the conventional fashion for extending an electrical circuit through the plug to the electrical appliance or the like which is attached to the remote end of the power cord 16.

The plug body portion 312 also is provided with a pair ofslots or openings 22 and 24, respectively, for receiving the metallic blade members 26 and 28 in rigidly supported postions within the body portion 12. Towards this end, each of the blade members 26 and 28 advantageously may comprise a terminal flange, such as the flange 3% on blade member 26 and the flange 32 on blade member 28, which is bent at right angles to the main axis of the blade member within the body portion 12 and to prevent its being displaced or pulled out therefrom.

In addition, each blade member is formed with a ferrule portion, such as the ferrule 34 of blade member 26 and the ferrule 3d of blade 28, adapted to receive an electrical conductor from the power cord 16. As known to those skilled in the art, good solid electrical contact is provided between each electrical conductor and its associated ferrule portion of the blade members as by crimping the ferrules therearound, or by soldering the ferrules thereto, or both.

As shown in FIGURES 1 and 2 of the drawing, the power plug lit is associated with a receptacle or socket member 38 formed in any desirable fashion and having a pair of spaced female slots it) and 42 formed therein for mating with and receiving the metallic blade members 26 and 28, respectively of the power plug 16?. The particular design, shape and construction, of the receptacle member 33 does not form a part of this invention and therefore need not be described in detail. It is important only that the receptacle 38 be provided with a pair of metallic contact members, such as the contact members 44 and 46 so that an electrical energizing circuit can be completed through the assembly when the blade members 26 and 28 of the power plug it are inserted within their respective slots 49 and 42. of the recep tacle.

It will be appreciated by those skilled in the art that the use of conventional and well-known power plugs involves the risk of possible electrical shock to the user when the power plug it) is inserted within the receptacle 3? an amount sufiicieut for the blade members 26 and 2% to come into energizing contact with the receptacle contact members 44 and M, respectively. Thus, in the act of pushing the plug member ltd towards the receptacle 33, as illustrated in FTGURE l for example, the fingers of the user may slip on the body portion 12 of the metallic blade members.

FIGURES 1 and 3 of the drawing, the body portion 12 thereon. should the plug 18 be picked up in a manner which otherwise would result in accidental contact between the the plug 18.

3 the power plug and accidentally touch the energized blade members 26 and 28. At other thnes, the power plug 18 may be grasped by the user in such a fashion that the fingers will overlap the front portion of the plug with the result that the fingers may be in energizing contact with the blade members thereof. This potential electrical shock hazard is particularly dangerous when the power plug is used by children who are too young or too careless to utilize proper safety precautions in the handling of the power plug. In accordance with a particular feature of the present invention, this potential shock hazard is eliminated by the provision of a unique barrier of electrical insulation material which is attached to the power plug intermediate the'finger gripping portion and As particularly shown in of power plug i=1? is advantageously provided with a plurality of co-planar flange members 26 and 28 which extend from opposite sides of the plug member 16 in a direction which is substantially perpendicular or transverse to the main axis of the plug and the metallic blade members thereof. a

As particularly shown in FIGURE 1, the transverse flanges 48 and form a barrier between the fingers and the metallic blade members so as to prevent accidental contact therebetween. Advantageously, the transverse 'flanges 48 and 58 are formed of an electrical insulation material and are made integral with the body portion 12 of plug 18, or if desired, may be formed separately and subsequently attached to the end of the plug 16.

Further, if desired, the body portion 12 of plug may be provided with suitable transverse serrations or grooves 52 at the finger receiving portions of the plug 10 to reduce accidental slippage or movement of the fingers Should the fingers slip on the plug It), or

fingers and the metallic blade members, the insulating barrier flanges 48 and 5t) serve to prevent any such ac- 4, sulating flanges 48 and 50 are shown in FIGURE 3 of the drawing as generally rectangular in shape, it will be appreciated by those skilled in the art that the manifest advantages of the insulating flanges are not limited to any particular shape or contour and that the flanges, if desired, may be made in different shapes such as semicircular or any other desirable configuration.

While there has been shown and described a specific embodiment of the present invention, it will, of course, be understood that various modifications and alternative constructions may be made without departing from the true spirit and scope of the invention. Therefore, it is intended by the appended claim to cover all such modifications and alternative constructions as fall within their true spirit and scope.

What is claimed as the invention is:

The improvement of an electrical shock-hazard proof power plug comprising the combination of a molded under pressure at the fingers on the body portion 12 of Thus, as illustrated by the dotted lines in FIGURE 1,, should the fingers move forward on the body portion 12 of plug 18, the transverse insulting flanges 48 and 58 will flex forwardly to cover the metallic blade members 26 and 28 and provide an additional safeguard in preventing accidental electrical contact between the fingers and the blade members. While the in power plug body ot'electrical insulation material, a power cord containing a pair of conductors extending through said body, and a pair of parallel, spaced-apart, metallic blade members rigidly secured to said body and extending outwardly therefrom, each of said blade members being connected to a respective one of said conductors within said body, said power plug body being formed 'with finger-receiving portions on its outer periphery to facilitate the insertion and removal of said power plug blade members into and out of the mating slots of a corresponding a power receptacle, and a pair of separate, spaced-apart co-planar, flexible, flange members of electrical insulation material extending outwardly from said power plug body transverse to said blade members, said flange members being positioned on opposite sides of said power plug body intermediate said finger receiving portions'and said blade members, said pair of flange members being formed of material sufliciently flexible to enable said flange members to flex forwardly under finger pressure for covering said blade members to provide an electrical- 1y insulating barrier for protecting the fingers from accidental electrical contact with the blade members when the latter are energized.

References @ited in the file of this patent UNITED STATES PATENTS 2,458,153 Festge Jan. 4, 1949 2,618,680 Cook Nov. 18, 1952 2,759,160 Kelley Aug. 14, 1956 2,866,172 Sapper cit al. Dec. 23, 1958 3,015,877 Francis Jan. 9, 1962 FOREIGN PATENTS 787,777 France July 16, 1935 480,619 Italy May 7, 1953

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