US3041576A - Outlet - Google Patents

Description

F. G. BELLEK `lune 26, 1962 OUTLET 2 Sheets-Sheet 1 Filed Sept. l2, 1958 l iNvENToR: FRANK G. BELLEK BY ATT' June 26, 1962 F. G. BELLEK 3,041,576

OUTLET Filed sept. 12, 195s 2 sheets-sheet 2 FIG. 4

i" i l INVENTOR: FRANK G. BELLEK /I 29' B W I ATT'Y United States Patent O1 3,041,576 OUTLET Frank G. Bellek, Chicago, lll., assignor to Bell Electric Company, Chicago, Ill., a corporation of Illinois Filed Sept. 12, 1958, Ser. No. 760,596 6 Claims. (Cl. 339-192) This invention relates to a power outlet and more specifically to a heavy duty electrical outlet or receptacle particularly suitable for use in connection with appliances, tools and machines having relatively high electrical power requirements such as ranges, dryers, Welders, blowers and the like.

An important object of the present invention is to provide an outlet or receptacle equipped with shiftable or adjustable connecting means for securely connecting the electric wires or cable of the outlet and the prongs of a plug inserted therein. Another object is to provide a receptacle having a plurality of clips which are tightly xed to the electric cable and which are capable of lateral displacement when engaged by the prongs of a plug to insure proper frictional and electrical contact with those prongs. In this connection, it is a specific object to provide oating spring clips which cooperate both with the walls of the receptacle and with the prongs of a plug so that the force exerted by the wiper blades of each clip is distributed substantially equally against opposite surfaces of a prong received therebetween.

Another object of the present invention is to provide an electrical outlet having self-seating movable clips, each of the clips being provided with clamping means by which electrical cables or wires may be readily attached thereto and detached therefrom. A further object of this invention is to provide a secure interconnection between the electric cables or wires and the spring clips without restraining movement of those clips upon engagement with the prongs of a plug. A still further object is to provide a receptacle having a slidable and non-removable rear cover which may be readily moved or Withdrawn to expose the cable clamping means for the several prongengageable spring clips disposed m'thin the receptacle.

Other objects will appear from the specicaiton and drawings in which:

FIG. l is a top plan view of a receptacle embodying the present invention;

FIG. 2 is a bottom view of the receptacle taken along line 2-2 of FIG. 3 and showing the removable rear cover plate therefor;

FIG. 3 is a longitudinal section of the receptacle taken along line 3 3 of FIG. 1;

FIG. 4 is a side elevation of the receptacle showing a fragmentary portion of the mounting plate therefor;

FIG. 5 is a transverse sectional view of the receptacle as viewed when looking upwardly from line 5-5 of FIG. 3;

FIG. 6 is a perspective view of the clip shown in section in FIG. 3;

FIG. 7 is a side elevation of a modied clip, the view being taken across a section 0f cable (shown in phantom) secured to the clip; and

FIG. 8 is a perspective view of the modified clip illustrated in FIG. 7.

Referring to the drawings, the numeral 10 generally designates an electrical outlet or receptacle having a body 11 and a slidable rear cover plate 12. These parts may be molded or formed from a phenol formaldehyde resin or from any other suitable material having electrical insulating properties. Since a number of insulating plastic materials are commonly used in connection with electrical devices, a discussion of such materials is believed unnecessary herein.

In the illustration given, the receptacle body 11 has a circular or disc-shaped upper portion 13 and a vertically elongated lower portion 14 formed integrally therewith. A central bore 15 extends longitudinally through the body, the bore being restricted at its lower end to restrain the head of a rear cover mounting rivet 16. As shown in FIG. 3, rivet 16 is freely received within the bore 15 of the body and is upset and swaged at its lower end to form a retainer head 17. As rivet 16 is tightcned, thehead 17 of the rivet is preferably driven into contact with the outer surface of a washer 17a which engages the rear or bottom cover plate 12 to hold the body 11 and plate 12 tightly together in slidable relationship.

From FIGS. l and 5 it will be seen that the lower portion 14 of the body has a plurality of radially extending wings 18, 19 and 2li. Each of the uniformly-spaced wings is provided with a longitudinally elongated charnber 21, the chambers being of a rectangular cross-section and opening through the bottom of the bodys lower section 14. Referring to FIGS. l and 3, it will be seen that the upper section or portion 13 of the body is provided with three vertical openings 22 communicating with the chambers 21 of the three wings. Viewed from the upper face of the body, the openings 22 are rectangular in shape with one of the openings extending radially. The other two rectangular openings are transversely bisected by radii of the circular upper body section 13. Preferably, the upper edges of openings 22 are beveled or ilared outwardly to facilitate insertion of the prongs of a plug through those openings and into chambers 21.

Removably disposed within the chambers 21 of the receptacle are gripping means 23 in the form of spring metal clips for frictionally engaging the prongs of a plug and for making electrical contact therewith. In the structure illustrated in FIGS. 1e6, each of the three clips has an apertured base 24 and a pair of upstanding side walls or arms 25 formed integrally therewith. The upper portions 26 of these paired arms 25 slope inwardly and upwardly toward each other and then, at their free ends, turn inwardly and downwardly to provide opposing, reversely-turned wipers 27 for frictionally gripping and for making electrical Contact with the prong of a plug disposed therebetween.

Each clip may be stamped and formed from sheet material having the necessary properties of lexibility and electrical conductivity. While bronze has been found particularly effective, it will be understood that other metals having similar properties may be used.

A pair of ears 28 are cut from the side walls or arms 25 of each clip and extend inwardly and downwardly towards the base of the clip. In FIGS. 3 and 6 it will be seen that ears 28 terminate in vertically spaced relation above the base 24 to form stops and that the laterally projecting flanges 29' of an inverted U-shaped holder or strap 30 are disposed between the upper surface of the base and the lower ends of the ears. As a result, the depending ears 28 restrain upward movement of the holder 30 without preventing horizontal sliding movement of that holder along the upper surface of the base for initial assembly purposes. A bolt or set screw 31 is threadedly received within the central aperture of the base 24 and projects upwardly into the channel defined by the inverted U-shaped strap 30' for clamping the end of a cable or wire 32 within that channel.

Longitudinal movement of the clips within the chambers is limited by an insulating washer 24a above the rear or 4bottom cover plate 12 an-d in turn by the washer 17a carried by the rivet head 17. As shown in FIG. 3, upward movement is blocked by a pair of shoulders 33 formed integrally in the walls of the recess 21 and spaced apart slightly more than the width of the opening 22 di- 3 Y rectly thereabove to engage the upper ends of the clip without interfering with inward and outward movement of the prongs 34 of plug 3S. Y

The receptacle may be connected by screws 36 to a suitable mounting plate 37 (FIG. 4) which is in turn connected to a stud or Vother wall or floor member. When so mounted, portion 14 of the receptacle body will be disposed ywithin the stud space of Vthe Wall with portion 13 disposed within an opening in the wallboard or plaster. Thus, the face of the receptacle will be substantially ush with the surface ofthe wall.

Referring now to FIGS- 2 and 3, it will bevseen that the rear or bottom cover plate `12 is provided with a pair of spaced parallel slots 38 on opposite Vsides of and longitudinally offset from an elongated central recess 39 to prevent relative rotation of the plate 12. Slots 38Y slidably receive depending nubs or projections 40 of the receptacle, body while recess 39 receives a depending extension 41 of the bodys central core portion.

Cover 12 is slidable across the rear face of the receptacle body between a closed position'wherein all of the clips 23 are locked within their chambers and an open position wherein the bolt connections 31 for a pair of clips are exposed for adjustment. 'A pair of notches or cutouts 42 are provided inthe rear cover so that the bolts 31 will be fully uncovered when the cover is shifted into its open position (not shown).

Preferably, the rear cover is held tightly in place against the base of the receptacle body by the rivet 16. Also, the presence of projections 40 within slots 3S and the non-circular configuration of core extension 41 prevent relative rotation of the rear cover and receptacle body. Therefore, by sliding cover 12, all of the cableclamping bolts 31 may be exposed for adjustment.

It is believed apparent from the foregoing that complete removal of the cover is not required for wiring the receptacle. Instead, the ends of the cables 32 may be simply inserted through openings 43 (FIG. 4) into the channels of the hat-shaped or inverted U-shaped strapsY 30 and then, by sliding the cover, the screws or bolts 31 foreach of the clips may be exposed and turned to clamp the ends of the wires tightly in place.

It will be noted that screws 31 perform a dual function as they are tightened; they tightly clamp the ends of the cables 32 within the channels of the inverted U-shaped straps and they securely lock the straps in place by urging those straps upwardly into tight frictional contact with depending ears 28. As a result, clips 23 may be readily secured to the ends of the cables, the bolt Y31V cable 32. holder 30 and the ears and side walls of the clip all cooperating to insure a positive and efficient electrical connection between the parts.

. Since the width of each -clip 23 is less than the lateral i dimension of the chamber in which that clip ,is disposed,

each of the clips is capable of limited lateral `displacement for equalizing" the force exerted by wipers 25 against the contact prong of a plug. Therefore, should the inserted prong 34 be out Iof register with the vertical plane passing between the opposing wiper arms of a clip, that clip will be capable of self-adjustment into a 'laterally displaced or tipped position whereinV the inward forces exerted by the prong-clamping Wiper arms of each clip will be substantially the same.

Cable 32 will not interfere with tipping movement or self-adjustment of the clip 23 because the axis of the cable portion received by strap 130 extends along a vertical plane passing between the paired wiper arms and spaced equidistant therebetween. Consequently, the cable need only twist slightly along its axis to accommodate the full range of tipping or tilting movement of the clip. FIGURES 7 and 8 show a modification of the spring clip construction presented in FIGURES l through 6. In this second embodiment the upper'portions 26 of the wiper arms 2S diverge or turn outwardly rather than inwardly as in the iirst form of the invention. In addi- Vact as extensions of the wiper arms 2S'.

tion, clips 23 are each provided with a pair of upwardly and outwardly extending spring fingers 50. In the illustration given, these lateral fingers are formed integrally with the clip and are cut out of or punched from the wiper arms 26. Normally the spring fingers curve upwardly and outwardly so that the distance between their upper free ends is greater than the width of `base 24. In other respects the spring clip 23', as well as the elements of the receptacle with which that clip operates, are identical with the structure 'described in connection with FIGURES l through 6.

Referring to FIGURE 7, it will be noted that the width of each clip 23 exclusive of spring lingers 50 is less than the corresponding horizontal dimension of the chamber 21 in which that clipis supported and that therefore the 'side Walls or arms 25 of each clip are normally spaced from the side walls of the chamber. However, the distance between the chamber side walls is less than the normal spread of spring lingers 50 so that when each of the removable clips 23 is disposed within its respective chamber the spring fingers will be under tension and will press outwardly against the chamber side walls.

An important aspect of this second embodiment lies in the fact that the upwardly and outwardly extending fingers 50 of the clips are formed integrallywith and As a result, the opposing forces exerted by the wiper arms against the prong of a plug depends not only upon the spring tension of the arms but also upon the tension of ngers 50 imposed by the confining side walls of the chamber 21. The gripping force of the wiper arms may thus be increased or decreased by controlling the tension of the spring fingers, as by increasing or decreasing their spread prior to insertion of Vthe clip, or by varying the dimensions of the fingers, orV by modifying the temper or tiexibility of the material from which those fingers as well as the remaining portions of the clips are formed. i

While in the foregoing specification two embodiments of the present invention have been disclosed in considerable detail for purposes of illustration, it will be understood `by those skilled in theart that many of these details may be varied considerably without departing from the spirit and scope of the invention.

I claim:

1. In an electrical receptacle, a body having at least one chamber open at opposite ends thereof and of substantially uniform cross section from one of the open ends, a spring clip disposed Within said chamber, said clip having a pair of spaced opposing wiper arms adapted to receive therebetween the prong of a plug inserted into said one of the open ends of said body, said clip having a base with a threaded aperture therethrough, a bolt threadedly received within said aperture,.a U-shaped member having anges resting upon said base and defining with said base on opening for receiving the end portion of a cable extending along a plane passing the axis of said bolt and Y equdistant between said wiper arms, said arms being provided with inwardly projecting elements bearing against said tianges for holding said U-shaped member against the base, and means restricting the openness of the other of said ends of said body to hold said clip in place.

2. In an electrical receptacle, a body having at least one chamber open at Vopposite ends thereof and of substantially uniform cross section from one of the open ends, a removable spring clip disposed within said chamber, said clip having a pair of spaced opposing wiper arms adapted to receive therebetween the prong of a plug inserted into said one of the open ends of said body, said clip having a base with a threaded aperture therethrough, a bolt threadedlyrreceived within said aperture, a U-shaped member having flanges resting upon said base .and defining with said base anopening for receiving the end portion of a cable extending along a plane passing the axis of said bolt and equidistant between said wiper arms, said arms being provided with inwardly projecting elements bearing against said flanges for holding said U-shaped member against the base, said clip being laterally pivotal within said chamber and abou-t the axis of said cable for equalizing the force exerted by said arms against said prong, and means restricting the openness of the other of said ends of said body to hold said clip ends in place.

3. In an electrical receptacle, a body having at' least one chamber open at opposite ends .thereof `and of substantially uniform cross section from one of the open ends, a removable spring clip disposed within said chamber, said clip having a pair of spaced opposing wiper arms adapted to receive therebetween the prong of a plug inserted into said one of the open ends of said body, said clip having a base with a threaded aperture therethrough, a bolt threadedly received within said aperture, a U-shaped member having flanges resting upon said base and defining with said base an opening for receiving the end portion a cable extending along a plane passing the axis of said bolt n and equidistant between said wiper arms, said arms being provided with inwardly projecting elements bearing against said flanges for holding said U-shaped member against the base, a pair of spring ngers formed integrally with said arms and extend generally in lthe direction of said arms away from the base, said ngers bearing outwardly against the sides of said chamber for urging said wiper arms into a tight frictional engagement with the prong disposed therebetween, said clip being laterally pivotal within said chamber and about the axis of said cable for equalizing the yforce exerted by said arms against said prong and to cooperate 'with said spring iingers to maintain the clip in a central position within the chamber atall times.

4. In an electrical receptacle, a body having a plurality of chambers therein of substantially uniform cross section opening through an end Wall of the body, a removable spring clip disposed Within each of said chambers, said clips having a pair of spaced opposing wiper arms reversely bent towards one another for receiving therebetween the prongs of a plug inserted into said chambers through the open end of said body, each of said clips having a base with a threaded aperture therethrough, a bolt threadedly received within said aperture, a U-shaped member having flanges resting upon each of said bases and defining with said bases an opening for receiving the end portion of a cable extending along a plane passing the axis of said bolt and equidistant between said wiper arms, said arms being provided with inwardly projecting elements bearing against said flanges for holding said U-shaped member against the base, said clips being laterally pivotal within said chamber and about the axis of said cable for equalizing the force exerted by said arms against said prong, and means restricting the openness of the other of said ends of said body to hold said clip ends in place.

, ble outwardly for frictionally receiving therebetween the contact prong of a plug, said base having a threaded aper;

ture therethrough, a bolt threadedly received within said aperture, a U-shaped element defining a cable receiving channel extending along a plane passing equidistant between said spring arms, said element having a pair of lateral flanges in contact with said base, said arms of said clip being provided with inwardly and downwardly extending ears bearing against said flanges to hold said element against said base.

6. A clipfor an electric outlet having a base and a pair of upstanding spring arms, saidarms having upper portions sloping inwardly towards each other and being flexible outwardly for frictionally receiving therebetween the contact prong of `a plug, said clip providing a pair of laterally and upwardly extending spring ngers formed integrally with said arms and adapted to urge said arms inwardly when said iingers are flexed towards each other, said upwardly extending spring fingers having free end portions capable of iiexing in the same direction as the upper portions of said arms, said base having a threaded aperture therethrough, a bolt threadedly received within said aperture, a U-shaped element dening a cable receiving channel extending along a plane passing equidistant between said spring arms, said element having a pair of lateral flanges in contact with said base along opposite sides of said aperture, said arms of said clip being provided With inwardly and downwardly extending ears bearing against said anges to hold said element against said Germany Jan. 12, 1944

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