US3488428A

US3488428A - Electrical receptacle

Info

Publication number: US3488428A
Application number: US653973A
Authority: US
Inventors: Charles E Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-07-17
Filing date: 1967-07-17
Publication date: 1970-01-06
Anticipated expiration: 1987-01-06

Description

Jan. 6, 1970 c. E. SMITH 3,488,428

ELECTRICAL RECEPTACLE Filed July 17, 1967 2 Sheets-Sheet 1 Jan. 6, mm c. E. 561m 3,488,428

I ELECTRICAL RECEPTACLE Filed July l7, 1967 2 Sheets-Shes t 2 wail/5 4* United States Patent 3,488,428 ELECTRICAL RECEPTACLE Charles E. Smith, Covina, Calif.,.assignor of one-third each to Vincent J. Cassone, Pasadena, Calif., and

Robert W. Seeger, Arcadia, Calif. Continuation-impart of application Ser. No. 494,534, Oct. 11, 1965. This application July 17, 1967, Ser.

- Int. Cl. H05k 5/02 US. Cl. 174-51 7 Claims ABSTRACT OF THE DISCLOSURE engaging the receptacle box and securing the electrical receptacle thereto. Lead wires are permanently secured to the electrical conductors and extend from the conductors disposed in the body to outside the body. The wall plate is provided with slots which are aligned with the conductors to receive prongs of an electrical plug. Alternatively, the wall plate can be provided with a slot to receive a lever of an electrical switch disposed within the body.

RELATED APPLICATIONS This is a contin-uation-in-part application of my copending patent application bearing Ser. No. 494,534 and filed on Oct. 11, 1965, now abandoned.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to electrical receptacles and more particularly to receptacles that are wall mounted and which are automatically secured to a receptacle box disposed in the wall when inserted therein and which are further provided with permanently attached lead wires for connecting the receptacle to electric wiring in the wall.

State of the prior art Presently available electrical receptacles and switches are provided with a yoke protruding past ends of the receptacle which includes apertures for receiving a pair of screws that engage matching threaded holes in a receptacle box and secure the receptacle to the box. They further include exposed connection terminals which are provided with screws to secure an electrical conductor to the terminal and to subject the terminal to an electric potential. The appearance of the thus mounted receptacle or switch and the receptacle box is unattractive and unsafe since the terminals are exposed and can be unintentionally touched. A wall plate is therefore secured to the receptacle by one or more screws which extend through the wall plate and engage threaded holes in the receptacle. The wall plate is of a size sufficient to cover all of the receptacle and the box. Only the wall plate is then visible from the outside and the external terminals of the receptacle are shielded from the outside.

More recently, receptacles have been constructed which include two or more apertures in their rear wall for connecting the receptacles to insulated conductor cables disposed in the wall. These receptacles have knife-edged connecting members which are biased toward the lead of the conductor cable by means of a spring or of a screw disposed adjacent the connecting member.

Although electrical receptacles an dswitches are widely and extensively used, they possess certain disadvantages. The principal problems center around high manufacturing and installation costs and certain safety hazards, particularly in conjunction with children tampering with the receptacles.

High manufacturing costs of modern receptacles principally are due to the relatively large number of parts, up to twenty or more individual parts in each receptacle for example, all of which must be individually manufactured and then assembled. With the exception of the terminals for connecting the receptacle to wall mounted wires, the exterior of the receptacle must be constructed of an insulating material such as Bakelite or other plastic material. To permit imbedding of all components in the insulating material, expensive dies are required to mold the often intricate shapes which, of course, further contributes to the cost of each receptacle.

Prior art receptacles are not only expensive to manufacture, but are also expensive to install. Each receptacle must be installed separately and independently by skilled personnel. A presently available receptacle requires the person installing it in a receptacle box in the wall to first loosen a pair of screws to permit the lead wires disposed in the wall at the receptacle box to be secured thereto. The wire must be bent, which is difficult because the wires are relatively heavy, placed around the screw and the screw must be tightened against the terminal. Frequently, the movement between the screw head and shaft, the terminal, and the lead wire causes the lead wire to move between the screw head and the terminal. The wire can become totally or partially disengaged. To insure a proper connection, the screw must be backed-off and the lead wire reinserted between the screw head and the terminal. Moreover, ends of the generally solid lead wires must be bent before they can be secured to the terminals of the receptacle. The wires are relatively heavy and become workhardened from a single bend. If they were inadvertently bent in the wrong direction they must be re-bent which, by virtue of their prior work hardening, frequently causes the ends to break off.

Proper installation, therefore, not only requires a substantial amount of time, which is costly, but also considerable skill on the part of the person installing it. A poor connection, which might become loose, is dangerous to human life as well as the building in which the receptacle is installed since it can result in a short.

Receptacles provided with rearwardly extending apertures are capable of receiving straight ends of the lead wires. The above mentioned danger of breaking the ends is thereby substantially eliminated. However, the knife edge constraining the wires to the receptacles givesa poor electrical connection resulting in high electrical resistance, a build-up of heat when the receptacle is exposed to high electrical loads, and a fire hazard. The knife edge makes it diflicult to remove the lead from the receptacle where the connecting member is spring biased. Frequently the lead must be severed to disconnect it from the receptacle. Alternatively, if the knifeedged connecting member does not engage the lead in a manner which makes it difiicult to disconnect the lead from the member, there is a danger that the two become inadvertently disengaged when the receptacle is installed in the receptacle box. Either alternative is undesirable and makes the receptacle somewhat unsatisfactory.

After the wall mounted lead wires are secured to the receptacle, the receptacle must be secured to the receptacle box, usually with the help of a pair of screws. To

enhance the appearance of the electrical outlet and to prevent the danger of a person unintentionally touching the exposed terminals of the receptacle, a wall plate is secured to the receptacle with the help of screws. The amount of time the operator spends in installing all parts is substantial. The operation must be repeated every time a receptacle or a switch is installed in a receptacle box in the wall. Thus, the actual costs of installing the receptacle are frequently higher than the already relatively high manufacturing costs.

The grounding of the receptacle frequently requires a third ground wire to be secured to a ground terminal of the receptacle. If the wall mounted wires do not provide for a ground wire, a separate ground connection must be made between the ground terminal and the receptacle box. This operation consumes a substantial amount of time.

Even after the receptacles have been installed and the wall plate secured thereto, they pose a danger to children which have a tendency to play with receptacle boxes and for whom it is relatively easy to remove the wall plate by undoing the screws securing it to the receptacle. As soon as the wall plate is removed, the terminals of the receptacle are exposed. The relatively small hands of children can easily reach them and the child, coming into contact with the hot terminals, receives an electric shock which can endanger his life. Moreover, prior art receptacles have several parts protruding past the wall plate which not only makes the receptacle unsightly, but also collects dust and dirt which is difficult to clean.

SUMMARY OF THE INVENTION Briefly, an electrical receptacle constructed in accordance with the present invention is adapted to be mounted in a cavity defined by a receptacle box disposed in a wall. The receptacle comprises a wall plate having an outline greater than an outline of the receptacle box and is provided with a pair of laterally spaced substantially parallel slots extending through the plate. The body has an out line capable of projecting into the cavity of the box and extends transversely away from a side of the wall plate. A cover is disposed adjacent an end of the body remote from the wall plate. A locking spring extends from the cover to adjacent the wall plate, is biased away from the body, and includes a plurality of teeth facing in the direction in which the spring is biased. The teeth engage the wall plate when the body projects into the cavity and secures the receptacle to the receptacle box. Means are further provided for the securing of the spring and the cover to the body and the wall plate. A pair of electrical conductors are disposed in the body, electrically insulated from each other and positioned adjacent the slots such that a portion of each conductor protrudes into an axial projection of a slot.

Preferably, a first lead wire has one end secured to one of the electric conductors and a second lead wire has an end secured to the other electric conductor. The lead wires extend from the conductors to the outside of the body and the cover. Other ends of the lead wires are accessible and can be secured to lead wires disposed in the wall and terminating in the cavity of the receptacle box.

In a preferred embodiment of this invention, the wall plate and the body are integrally constructed of a plastic material and are injection-molded. This receptacle, which now includes the wall plate as an integral part thereof, comprises no more than eight parts all of which are of a simple construction. All parts of the receptacle are manufactured and assembled at a cost which is substantially less than was heretofore possible.

Moreover, the installation procedure is simplified to such an extent that a receptacle can be fully wired and installed in a receptacle box in a fraction of the time in which presently available receptacles are installed. To install this receptacle, the operator simply twists the ends of the lead wires to the ends of the wall lead wires disposed in the receptacle box and secures the two together with the help of conventional wire nuts. No tools are required for this operation and the electrical connection between the ends of the respective wires is substantially better than when a wire is secured to a terminal by a screw head since a substantially greater contact surface between the wire surfaces is assured. Thereafter, the receptacle is pushed into the receptacle box such that the body of the receptacle protrudes into the cavity of the box. Simultaneously therewith, the teeth disposed on the locking spring engage an edge of the receptacle box and secure the receptacle thereto. No further operations are necessary. The insertion of the body of the receptacle into the cavity is the same operation as was necessary heretofore to install a"conventionalreceptacle. But while it was necessary in the past to secure the receptacle to the box with a plurality of screws, this operation of inserting the body into the cavity now simultaneously secures the receptacle to the box.

Once secured to the receptacle box, the receptacle can only be removed therefrom with a specially adapted removal tool. This removal tool is not readily avail-able. Children tampering with a receptacle, which have usually a screw driver at hand or can procure a make-shift screw driver, such as a conventional knife for example, are thereby prevented from demounting the receptacle and exposing themselves to the danger of receiving an electric shock. Moreover, when the receptacle is removed from the box, no energized conductors are exposed as, for example, the heretofore exposed terminals of the receptacle. The safety hazard of unintentionally coming into contact with the terminals, which might be subjected to an electric potential, is thereby also eliminated.

Preferably, the locking spring is constructed of metal and includes a prong extending into the body adjacent an aperture in the wall plate which receives a grounding prong of the plug to provide an automatic ground connection. The grounding of the receptacle therefore requires no independent operation and is performed simultaneously with the insertion of the receptacle in the receptacle box.

Prior art receptacles can be provided with flexible lead wires permanently secured to the electric conductors disposed within the receptacle to obtain the advantages of this invention. These lead wires are preferably of the stranded type to facilitate their quick connection to the solid lead wires disposed in the wall. Perhaps the most time consuming installation step, namely connecting the receptacle to the wall lead wires, is thereby greatly facilitated since it is no longer necessary to bend solid wires, secure them to terminals of the receptacle and ascertain that the connection is satisfactory. Instead, the leads from the receptacle are quickly twisted to the wall leads, which assures the best electrical connection between the two, and the joint is protected by a wire nut slipped over the joined ends of the wires.

The features of this invention, namely the simple construction of the wall plate and the body, the locking spring for mounting the receptacle in the receptacle box, and the lead wires secured to the electric conductors and extending outside of the body of the receptacle can additionally be utilized in conjunction with other electrical devices such as electrical switches, for example. Generally prior art wallmounted switches had no grounding provisions. A switch provided with a locking spring similar to the locking spring employed in conjunction with the, receptacles however includes the automatic grounding feature described above. A lever of the electric switch then projects past the wall plate and a switching mechanism is disposed in the body. In all other respects the electric device is identical to the just described receptacle. Its safety features as well as the-quick and low cost installation are thereby obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational view, with parts broken away, of a receptacle constructed in accordance with the present invention;

FIG. 2 is a rear elevational view of the receptacle;

FIG. 3 is a side elevational view, in section, taken along line 3--3 of FIG. 2;

FIG. 4 is an end view of the receptacle shown in FIG. 1;.

FIG. 5 is a fragmentary side elevational view, in section and with parts broken away, of an electrical switch constructed in accordance with the present invention and installed in a receptacle box'disposed in a wall;

FIG. 6 is a fragmentary front elevational view, with parts broken away, of the electric switch shown in FIG. 5;

FIG. 7 is a plan view of a tool adapted to remove the receptacle from the receptacle box;

"FIG. 8 is a plan view of an electric conductor constructed according to this invention and having a flexible lead wire welded thereto; and

1 FIG. 9 is a side 'elevational view of the conductor shown in FIG. 8.

" DESCRIPTION OF THE PREFERRED EMBODIMENT Initially, in referring to FIGS. 5 and 6, there is shown a wall 10 mounting a conventional receptacle box 12 which defines an outwardly-opening cavity 14. The box includes a plurality of push-out discs 16, at least one of which is removed when the box is installed to permit a metal conduit or insulated cable (not shown) carrying the wall le'ad wires 17 to be secured to the box. The box has a substantially rectangular configuration, best seen in FIG. 6, and includes flanges 18 extending from the sides of the box towards its center and defining a rectangular opening 20. A pair of laterally spaced grooves 22 are disposed in a pair of parallel flanges and are aligned with each other. The flanges can be constructed integrally with the sides of the receptacle box, or they can be defined by an adapter plate 23 secured to the receptacle box by means of a pair of screws 24 which engage threaded holes (not shown) disposed in a pair of lugs 26 projecting from the sides of a conventional box toward the cavity 14. Preferably, the adapter plate includes arcuately shaped slots 25 to provide for its adjustability relative to the box and to enable it to be vertically oriented. The adapter plate can further include a cover (not shown) such as a plastic skin over the opening 20 to prevent dirt and other foreign particles from collecting in the box prior to the installation of a receptacle or switch. The box 12 is adapted to receive an electrical switch as shown in FIGS. 5 and 6 or a receptacle as shown in FIGS. 1-4 and they are installed in the box after the cover or plastic film has been removed from the opening.

FIGS. l-4 show an electrical wall outlet or receptacle 28 adapted to receive a pair of plugs (not shown). The receptacle can, of course, be adapted to receive only one plug or to receive more than two plugs without altering its essential features. It can further be adapted for use in conjunction with plugs having three or more conductor prongs depending on the particular application.

The receptacle includes a substantially rectangular wall 'plate 30, which has a'periphery which is greater than the periphery of the receptacle box 12 shown in FIG. 6, enabling the receptacle box to be completely hidden when the wall plate is secured to the box. A rectangular body 32 has an outline which is less than the outline of the rectangular'opening 20 of the receptacle box 12 (best seen in FIG. 6), and extends transversely away from a side 34 ofthe Wall plate. A cover 36 disposed adjacent an end of the body remote from the wall plate and a substantially U-shaped locking spring 38, are secured to the wall plate and the body by a suitable fastener such as a rivet 40 or a screw (not shown). A pair of laterally spaced conductors 42 and 44 (best seen in FIGS. 8 and 9) are insulated from each other and are disposed within the body 32 of the receptacle 28.

The wall plate 30, a front side 46 of which is preferably flat but can be provided with an ornamental design, includes pairs of laterally spaced slots 48 which are spaced apart to receive spaced apart prongs (not shown) of an electrical plug (not shown). The wall plate has no projecting parts, covers, etc. which can collect dust and dirt and can therefore be easily wiped clean. The slots are substantially parallel in a direction transverse to said 34 of the wall plate to permit the axial insertion and removal of the prongs of the electrical plug. The number of pairs of slots corresponds to the number of electrical plugs the outlet can receive. One electric conductor is arranged in the body such that its prong-engaging portions 50 protrude into an axial projection of one of the slots of each pair of slots. When the prong of the plug is inserted into the slots of the wall plate, it engages the prong-engaging portion 50 of the conductor and makes electric contact therewith. Similarly, prong-engaging portions 50 of the other conductor protrudes into the axial projection of the other of the pair of slots. The conductors are of a onepiece construction, whether they are provided with one or more portions 50. A center portion 51 of the conductors is flat and the prong-engaging portions are formed from the same piece of material as is the center portion.

As best seen in FIGS. 1 and 3, the wall plate 30 includes a raised center portion 52 which protrudes into body 32 and defines a pair of substantially parallel and straight grooves 54 intermediate the center portion and side walls 56 of the body. The grooves have a width about equal to a thickness of the

conductors

42 and 44 and together with cover 36 position and hold the conductors in the receptacle. The center portion adjacent slots 48 in the wall plate defines recesses 57 to receive the prong-engaging portions 50 of the conductors. Rivet 40 is imbedded in the center portion 52 and extends away from the body towards cover 36 as best seen in FIG. 3. Alternatively, the center portion may be provided with a threaded hole (not shown) to receive the threaded shaft of a screw (not shown) which secures the locking spring 38 and cover 36 to the body and the wall plate.

Preferably, an end of a first lead wire 58 is secured to the electric conductor 42 and an end of a second lead wire 60 to the electric conductor 44. The lead wires, which are insulated and stranded, extend through a pair of laterally spaced holes (not shown) in the cover 36. The other ends of the lead wires are disposed outside the body and the cover of the receptacle. Preferably, the ends of the lead wires are stripped of the insulating material to facilitate their later installation. In the preferred embodiment of this invention, the ends of the lead wires secured to the conductors are welded thereto which assures lowest manufacturing costs and prevents the removal of the lead wires after they have been installed.

The U-shaped locking spring 38 includes a pair of legs 62 joined to and extending from a center portion 64 of the spring adjacent the cover 36 towards and adjacent to side 34 of wall plate 30. The legs are angularly inclined with respect to side 34 of the wall plate such that the ends of the legs adjacent the wall plate are further apart than the ends of the legs adjacent the center portion 64. When the ends of the legs adjacent the wall plate are compressed in opposing directions towards each other, a spring force biases the legs outwardly of the body 32. Each leg further includes a laterally spaced flange 66 which is integrally constructed with the legs and provided with a plurality of teeth 68 (best seen in FIG. 4) extending away from the legs in the same direction as the spring force biases the legs when they are compressed. Preferably, the teeth are sloped downwardly, as seen in FIG. 4, such that when they engage an edge, the receptacle can move in one but not in the, other opposite direction.

The receptacle includes an aperture 70 adjacent each pair of slots 48 which extends from face 46 of the Wall plate to the end of center portion 52, as best seen in FIG.

3, for receiving the grounding prong of a plug. The locking spring 38 is provided with an elongated prong 72 arranged substantially transverse to the center portion 64 of the spring and projecting through an aperture 74 in the cover 36 towards aperture 70 in the wall plate and the center portion 52. If the receptacle is a double outlet, the center portion of the spring is constructed such that it has a width approximately equal to the spacing of adjacent apertures 70 in the wall plate. A pair of substantially parallel prongs 72 then extends into each aperture. Prong 72 is flexible and protrudes into aperture 70 such that a prong (not shown) of the grounding plug engages prong 72 of the spring and is electrically connected therewith. Since the flanges 66 of the locking spring engage the flanges 18 of the receptacle box 12, the spring, as well as the prong of the grounding plug, are grounded. In this instance, the locking spring is constructed of metal such as copper, brass, or spring steel.

In a preferred embodiment of this invention the wall plate 30, the body 32, and the center portion 52, are integrally constructed of an insulating material such as Bakelite, and are preferably injection-molded to assure low manufacturing costs. Most conveniently, the rivet 40 is molded into the center portion 52.

The receptacle 28 is installed in the receptacle box 12 by first twisting the stripped ends of each of the

lead wires

58 and 60 to corresponding stripped ends of the wall lead wires 17. After the ends have been so twisted about each other, a conventional wire nut 76, shown in FIG. 5, is placed over the twisted ends of the wires. The ends are now insulated and prevented from becoming untwisted. Next, the flanges 66 of the locking spring 38 are aligned with the grooves 22 in flanges 18 of the receptacle box 12, which grooves are laterally spaced an amount equal to the lateral spacing of the flanges 66. Ends of the flanges adjacent center portion 64 are closer to each other than the spacing of the bottom of the grooves 22. The ends of the legs adjacent the wall plate 30, however, are spaced apart an amount further than the spacing between the bottoms of the grooves. The spring is therefore compressed such that legs 62 are substantially parallel to each other and the receptacle is axially pushed into the receptacle box until side 34 of the wall plate 30 is substantially flush with wall 10. At this point, the body projects into cavity 14 and the teeth 68 of the locking spring 38 engage the bottom of the grooves 22. Since the teeth are sloped in the direction in which the receptacle has been inserted into the receptacle box, the receptacle is effectively locked to the box and cannot be removed therefrom. Installation of the receptacle is now complete and it is ready for use. At the same time the receptacle has been automatically grounded since an electric connection is established between the receptacle box and the locking spring.

If the receptacle is to be removed from the box, an especially adapted removal tool 78, shown in FIG. 7, must be used. Unauthorized removal, especially by playing children, is thereby made substantially more difficult because they must first be in the possession of the special removal tool which can be hidden or made otherwise inaccessible to them. The removal tool 78 is preferably constructed in the form of a pair of pliers having arms provided with inwardly extending flat blades 80 which are movable towards and away from each other by pivoting the arms of the pliers. The distance between the pivot point of the arms of the pliers and the flat blades is relatively long to'enable the ends of the fiat blades to be removed from each other a distance which is greater than the width of wall plate 30.

The wall plate includes a pair of grooves 82 in side 34 which extend from the periphery of the wall plate to the side walls 56 of the body such that the legs 62 of the locking springs are disposed in an area of the cross section of the groove. The grooves define a reces between the wall and the wall plate 28 into which the flat blades can be inserted. By compressing the handles of the removal tool 78, the free ends of the blades contact the ends of the legs adjacent wall plate 28 and compress them. When the legs are compressed, i.e., when they are substantially adjacent and parallel to side walls 56 of the body 32, the teeth 68 are disengaged from the bottom of grooves 22 and the receptacle can be freely removed from the receptacle box 12.

To assure proper engagement of the legs 62 by the blades 80 of the removal tool, enlarged recessed portions 84 (shown in FIG. 2) ar provided in the wall plate adjacent the legs and body 32 to enable the ends of the legs to project past the side 34 of the wall plate as shown in FIG. 4. The receptacle is reinserted into the receptacle box as described above.

Shown in FIGS. 5 and 6 is a wall mounted electric switch 86 provided with an actuating lever 88 projecting past a substantially rectangular aperture 90 in a Wall plate 92 which is otherwise identical with wall plate 30 of receptacle 28.

A body 94 has a configuration similar to that of body 32 and is secured to a side 96 of wall plate 92 and includes a pair of electrical conductors (not shown) which are selectively electrically connected by actuating the lever 88 of the switch. A pair of

lead wires

58 and 60 are secured to the conductors in the manner described in conjunction with conductors 42 and 43 of the receptacle 28 and protrude through the body and have preferably stripped ends which are positioned outside the body. A U-shaped locking spring 98, identical to locking spring 38 of receptacle 28, is secured to the body by means of rivet 40 and includes center portion 64, the pair of legs 62, the laterally spaced flanges 66, and teeth 68 identically to spring 38. The side 96 of the wall plate also includes a groove 82 to permit insertion of the removal tool 78.

Switch 86 is installed into the receptacle box 12 in a manner identical to that described in conjunction with the description of the installation of receptacle 28. The

lead wires

58 and 60 of the switch are first connected with the wall lead wires 17, a wire nut 76 is secured to each connection to insulate and protect the connection, and the body of the switch is inserted into the rectangular opening 20 defined by flanges 18 of the receptacle box 12. The switch is moved towards the receptacle box such that the body 94 projects into the cavity 14 until side 96 of the wall plate 92 is substantially flush with wall 10. The switch is now installed and ready for use. Simultaneously with its installation it is automatically grounded by the locking spring which engages the receptacle box. It is removed from the receptacle box with the help of the removal tool 78 as described above.

This switch incorporates the same advantages as the receptacle 28 constructed in accordance with this invention. More particularly, it permits a quick connection of the lead wires with the wall lead wires and substantially instantaneous installation of the switch in the receptacle box without having to attach either the switch or the wall plate to the box with a plurality of screws. In addition, the above referred to safety features are obtained by making it practically impossible for somebody not in the possession of the special removal tool to remove the switch from the receptacle box, and by having no externally accessible terminals on the switch or the receptacle.

I claim:

1. An electric receptacle for receiving a multiconductor plug and adapted to be mounted in a cavity defined by a receptacle box disposed in a wall, the receptacle comprising:

(a) a plate having an outline greater than an outline of the receptacle box and provided with at least a pair of laterally spaced, parallel slots extending through the cover,

(b) a body having an outline capable of projecting into the cavity of the box and extending transversely away from a side of the plate,

(c) a cover adjacent an end of the body remote from the plate,

(d) a U-shaped locking spring constructed of metal including a center portion disposed adjacent and parallel to the cover and apair of legs extending in the direction of the plateand biased away from the body, the legs including a -plurality of teeth facing in a direction away from the cbody, the spring further including a prong extending from the center portion toward the plate through an aperture in the cover into a projection of an aperture extending through the plate adjacent the pair of slots,

(e) means for securing the spring, cover and body to the plate,

(f) a pair of electric conductors disposed in the body, electrically insulated from each other and positioned adjacent the slots such that a portion of one conductor protrudes into an axial projection of one slot and a portion of the other conductor protrudes into an axial projection of the other-slot, and

(g) a first lead wire having an end secured to one of the electric conductors and a second lead wire having an end secured to the other electric conductor, the lead wires extending from the conductors to outside the body and cover.

2. Apparatus according to claim 1 wherein the plate and the body are integrally constructed and wherein the plate includes a groove intermediate "the body and a periphery of the plate and adjacent the locking spring.

3. An electrical receptacle for receiving multiconductor plug and adapted to be mounted in the cavity defined by a receptacle box disposed in a Wall the receiptacle comprising:

(a) a plate having an outline greater than an outline of a receptacle box and provided with at least a pair of laterally spaced parallel slots extending through the cover,

(b) a body formed integrally with the plate and having an outlet capable of projecting into the cavity of the box and extending transversely away from the side of the plate,

(c) a cover adjacent an end of the body remote from the plate,

((1) a U-shaped locking spring having a center portion disposed adjacent and parallel to: the cover and a pair of legs biased away from the body and extending to adjacent the plate, each'leg including a pair of laterally spaced flanges provided with teeth,

(e) means for securing the spring and cover to the body,

(f) a pair of electric conductors disposed in the body, electrically insulated from each other and positioned adjacent the slots such that a portion of one conductor protrudes into an axial projection of one slot and a portion of the other conductor protrudes into an axial projection of the other slot,

(g) a first lead wire having an end secured to one of the electric conductors and 'a second lead wire having an end secured to the other electric conductor, the lead wires extending from the conductors to outside the body and cover, and

(h) an adapter plate connected to the receptacle box, the adapter plate having a cutout for receiving the body and pairs of laterally spaced grooves extending from the cutout toward a periphery of the plate for engaging the teeth on the flanges, the body being inserted into the cutout in the adapter plate with the teeth on the flanges of the locking spring engaging the grooves in the adapter plate.

4. In an electrical receptacle or switch for connection to electrical wiring in the wall of a building and adapted to be mounted in a cavity defined by a receptacle box disposed within the wall, the box including a pair of parallel flanges which define two sides of the opening into the cavity, the combination which comprises:

(a) a plate having an outline greater than an out line of the receptacle box,

(b) a body secured to the plate and having an outline capable of projecting into the cavity of the box and extending transversely away from a side of the plate,

(c) a U-shaped locking spring having a center portion secured to the body remote from the plate and a pair of legs extending toward the plate and away from the body beyond the distance between the receptacle box flanges, the legs having a plurality of teeth facing away from the body, the ends of the legs being compressible toward each other adjacent the plate, whereby the teeth will engage the flanges when the body is inserted into the receptacle box to prevent removal of the body until the spring legs are compressed toward each other,

((1) a pair of electrical conductor disposed within the body, and

(e) a pair of insulated lead wires electrically connected at one end to the electrical conductors and extending outside of the body for connection to the electric wiring in the Wall.

5, The combination as defined in claim 4 wherein the body completely encloses the electrical conductors, whereby the receptacle or switch may be safely handled after the lead Wires are energized.

6. The combination as defined in claim 5 wherein each of the legs of the locking spring include a pair of spaced flanges extending at right angle to the body, each of the flanges having a plurality of teeth adapted to engage the receptacle box flanges.

7. The combination as defined in claim 6 wherein the plate includes a pair of grooves intermediate the body and extending from the periphery to the ends of the legs of the locking spring.

References Cited UNITED STATES PATENTS 1,835,554 12/1931 Both 17455 X 1,927,245 9/1933 Russell 174-51 X 1,999,194 4/1935 Hubbell 17457 2,437,802 3/1948 Adler 174-55 X 3,219,966 11/1965 Murakami 20051.17 X 3,272,978 9/1966 Jackson.

OTHER REFERENCES The Radio-Electronic Master, 1958, 22nd edition, United Catalog Publishers Inc., Hempstead, N.Y., p. L-735.

LEWIS H. MYERS, Primary Examiner D. A. TONE, Assistant Examiner US. Cl. X.R. 17455, 57