US2024415A - Electrical plug - Google Patents

Description

' Dec. 17, 1935.

J. G. ALLEN, JR

ELECTRICAL PLUG Filed April 9, i954- Patented Dec. 17, 1935 UNITED STATES PATENT OFFlCE 4 Claims.

This invention relates to new and useful improvements in electrical plugs.

One object of the invention is to provide an improved plug which eliminates the usual metal fastenings for the lead wires.

Another object of the invention is to provide an improved plug which is easily and quickly assembled or dissembled, whereby the connection of the lead wires thereto is readily accomplished.

A further object of the invention is to provide an electrical plug which is so arranged as to provide a constant positive contact of the lead wires with the contact prongs of said plug.

Still another object of the invention is to provide an electrical plug which is constructed in two pieces, whereby manufacture is simplified and also a more efiicientplug is provided.

A particular object of the invention is to' provide'an improved electrical plug which has the lead wires secured thereto by bending the same around projections within the plug and is arranged in such a way that the exposed ends of the wires frictionally engage the contact prongs of the plug, thereby assuring a positive contact.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawing, in which an example of the invention is shown, and wherein:

Figure l is an elevation of a plug, constructed in accordance with the invention.

Figure 2 is a vertical sectional view of the same.

Figure 3 is a vertical sectional view, taken at right anglesto Figure 2.

Figure 4 is a view similar to Figure 2 showing the block partly removed from the shell of the plug.

Figure 5 is a view similar to Figure 4, and taken at right angles thereto.

Figure 6 is a horizontal cross sectional view, taken on the line 6-6 of Figure 4,

Figure 7 is an isometric view of the block, and

Figure 8 is an elevation of a modified form of contact prongs.

In the drawing, the numeral It designates the concave-convex shell of an electrical plug which is generally circular in cross section. The shell is constructed of suitable insulating material and has a depending annular fiange H at its lower end. A hollow tubular fiared extension I2 is provided at the upper end of the shell and said extension, shell and flange are all made integral, being of the same material and constituting the body of the plug.

Within the shell of the plug, a pair of diametrically opposite bosses i3 are positioned. 5 These bosses are of insulating material and are preferably made integral with the shell l0. Elongated fiat contact prongs I4 are provided with brackets I4 secured to the bosses l3 by screws I5 and extend outside the body a sub- 10 stantial distance from the flange H. Although I have shown the prongs secured by the screws l5,.it is obvious that any suitable means may be employed to'fasten said prongs to the bosses.

Further, prongs M (Fig. 8) could be substituted for the prongs I4. Each prong l4 comprises a flat piece of metal bent upon itself as shown to form a prong and fastening bracket of a single piece of metal.

As is .well known, the contact prongs conduct 20 the electrical current to or from the lead wires A and B which engage said prongs. The usual method is to secure the exposed ends of the Wires to the screws, thereby making electrical connection with the prongs. The connection 25 must be made with tools, and due to the necessary smallness of the plug, it is difficult and tedious to properly secure the wires to said screws. The connections when finally made are poor and insecure, because any strain on the 30 wires A and B is taken by the outer fastened ends of the wires, resulting in loosened contacts short circuiting and causing fuse blowouts, and other troubles.

For electrically connecting the lead wires A 35 and B to the contact prongs I4 to overcome the above disadvantages, a square block I6 is provided. This block is positioned centrally of a circular plate or disk I? which is made integral with or fastened to the lower end of the block. The block 40 and disk are constructed of any suitable insulating material, such as hard rubber, rubber compound, and the like. The block is arranged to be inserted into the shell Ii) of the plug, two of the sides [9 of the block lying contiguous to 45 the inner fiat sides .of the prongs I4 and the periphery of the disk engaging the inner rim of the flange I I (Figures 2 and 3). Slots l6 are provided in the disk adjacent the sides 19 of the block and the prongs I4 pass downwardly 50 through these slots when the block is in position within the shell In. It is noted that the disk has a close fit within the flange ll.

Both the lead wires A and-B are fastenedin I the block in the same way and it is believed that 55 a description of one will suflice. For securing the lead wire A to the block, said block is provided near its upper end with a diagonal duct I8 which extends horizontally through said block. One end of the duct terminates at one of the sides I9 of the block which lie contiguous to one of the prongs l4 when the block is in position within the shell H), the other end terminating at the adjacentside 20 thereof. A flange 2| extends outwardly from the side 20 near its lower end and this flange extends substantially the width of said side being made integral therewith. Each end of the flange is provided with a notch 22 and at the upper central portion of the side 20, a small recess 23 is formed.

In securing the wire A in the block, said wire is passed downwardly through the extension l2 and through the shell of the plug. The block I6 is not in position within said body at this time, being free therefrom. The wire A is laid in the recess 23 and passed under and around the flange 2| (Figure 7 engaging in the notches 22 to prevent its disengagement from the flange. The end of the wire is bent upwardly and is pushed into the duct |8 from the side 20, through the duct and out onto the side H). The end of the wire is then bent so as to lie along the flat side l9. It is pointed out that only that part of the wire lying along the side |9 is exposed, the remainder being suitably covered with insulation a. Due to the winding of the wire around the flange 2|, its engagement in the notches and duct and its bending, said wire is prevented from slipping, once it is in position.

A diagonal duct I8 is provided on the opposite side of the block l6 and another flange 2| is formed on the opposite side 2E The wire 13 is passed downwardly through the shell I of the plug, is wound around the corresponding flange 2| and is pushed through, the second duct I8, having its outer end exposed and lying along the second side N! of the block.

When the wires have been secured to the block, as above described, the block is slid upwardly within the shell |0, theprongs M entering the spots I6, whereby the block passes upwardly between the prongs, the inner sides of said prongs engaging the exposed ends of the wires A and B which lie along the sides IQ of the block. The contact prongs are placed sufliciently close to each other so that as the block slides upwardly therebetween, said prongs will frictionally engage the ends of the wires A and B. This frictional contact not only serves to hold the block securely within the shell, but also affords a perfect and positive electrical connection between the prongs and wires.

The wires A and B are secured in the block before the same is inserted into the shell of the plug. This permits plenty of room in which to make a fastening and also eliminates the necessity of using tools with which to secure the lead wire to said block. When the block is slid upwardly within the shell the wires A and B tightly engage the inner sides of the prongs l4 and frictionally hold said block within the shell. If any undue strain is placed on the wires A and B, it will be seen that said strain will be taken by a goodly portion of the inner end of the wires and not by a small portion of said Wires at their extreme inner ends, as is the case in the 'usual plug which depends on screw connections for its fastenings. It is obvious that the block is readily assembled and disassembled to attach and detach the lead wires A and B to the block. By eliminating the usual screw contacts, the danger of the electrical connection jarring loose, as well as the difficulty of making said connection, is eliminated.

The description which has been given recites more or less detail of a particular embodiment of the invention, which is set forth as new and useful; however, I desire it understood that the invention is not limited to such exact details of construction, because it is manifest that changes and modifications may be made, within the scope of the appended claims, without departing from the spirit of the invention. 15

What I claim and desire to secure by Letters Patent, is:

1. An electrical connection plug comprising, a hollow body, metallic contact prongs mounted in said body and extending outward from the front 0 face thereof, a block insertable in the body from the front face thereof between the prongs, and a disk at the lower end of the block and having slots through which said prongs project when the block and disk are inserted in said body, said block having means for engaging circuit wires and holding the ends thereof in frictional contact with said prongs, said frictional contact maintaining the connection plug assembled.

2. An electrical connection plug comprising, a hollow body, metallic contact prongs mounted in said body and extending outward from the front face thereof, a block insertable in the body from the front face thereof between the prongs, and a disk at the lower end of the block connected therewith and having slots therein for receiving the contact prongs when the block is within the body, projections on said block for receiving circuit wires and openings through the block through which bared ends of said circuit wires extend, said block holding the ends of said wires in frictional contact with the prongs when the block is positioned within the body, said frictional contact maintaining the connection plug assembled.

3. An electrical connection plug comprising a hollow body, metallic contact prongs mounted in said body and extending outward from the front face thereof, and a block having openings therein for receiving circuit wires with the ends of said circuit wires passing through said openings, said block inserted in the body from the front face thereof between the prongs and serving to' hold the extending ends of said wires in electrical contact with the prongs when the block is positioned therebetween, said frictional contact maintaining the connection plug assembled.

4. An electrical connection plug comprising, a hollow body, metallic contact prongs mounted in said body and extending outward from the front 50 face thereof, a block having openings therein for receiving circuit wires with the ends of said circuit wires passing through said openings, said block inserted in the body from the front face thereof between the prongs, and projections on 5 the member around which said wires are engaged before passing through said openings to more securely fasten the same to the block, said block serving to hold the extending ends of said Wires in electrical frictional contact with the prongs when the block is positioned therebetween, said frictional contact maintaining the. connection plug assembled.

JOHN G. ALLEN, JR.

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