US2665341A - Shockproof locking electrical plug and receptacle - Google Patents

Description

Jan. 5, 1954 w. H. wlLsoN 2,665,341

SHOCKPROOF' LOCKING ELECTRICAL PLUG AND RECEPTACLE 2 shees-sheer 1 Filed Feb. 26, 1955 e .l .ma

BYU

ECEPTACLE Jan. 5, 1954 w. H. WILSON SHOCKPROOF LOCKING ELECTRICAL PLUG AND R 2 Sheets-Sheet 2 Filed Feb. 26, 1955 IN VENTOR met Harvey Vl/Lvon ATTORNEY Patented Jan. 5, 1954 SHOCKPROOF LOCKING ELECTRICAL PLUG AND RECEPTACLE Walter H. Wilson, Mansfield, Ohio Application February 26, 1953, Serial No. 339,020

8 Claims. (Cl. 20G- 50) This invention relates to a shock-proof locking electrical plug and receptacle, and has for an object to provide an improved electrical plug and receptacle so cooperating with each other that the plug is first locked in the receptacle as it moves into circuit completing position, and cannot be unlocked from the receptacle until after it has been moved away from the circuit completing position.

A further object of this invention is to provide an electrical plug and receptacle wherein it is very diiiicult to insert a foreign object in such a manner as to complete a circuit through the receptacle, but wherein if the foreign object happens to be shaped sufficiently close to the shape of the plug, it cannot act to shock the person using the foreign object, but instead, will ground the circuit through the receptacle and probably blow out the fuse.

A further object of this invention is to provide an electrical plug and receptacle wherein when the plug is in circuit completing position, it is locked therein and cannot accidently or intentionally be removed therefrom until after the circuit has first been broken.

Still a further object of this invention is to provide an electrical receptacle which will either resist the entrance of a foreign object therein, or will short circuit and ground, should the foreign object be successfully manipulated to reach and complete the circuit thereto.

Still a further object of this invention is to provide a shock-proof receptacle for a male electrical plug wherein a foreign object will have difficulty in completing a circuit, but if it does succeed in completing the circuit, then the circuit will be completed only by grounding it through the receptacle, and thus, blowing any fuse on the line, and in any case, preventing any shock from reaching the person using the foreign object in the receptacle. In this way, a small child inserting a foreign object in the receptacle, such as a nail, hair pin, or darning needle, or the like, could probably not succeed in operating the receptacle to complete the circuit, or if a child did succeed in completing the circuit, the circuit when completed would ground through the receptacle, and would not shock the child.

Still a further object of this invention is to provide a shock-proof locking electrical plug and receptacle wherein the receptacle is usually so placed in a wall that the plug must be inserted in a horizontal direction, and then, after completely inserted must be moved downwardly somewhat, first causing the plug to be locked in the receptacle, and then, after it is so locked, completing the circuit from the receptacle to the plug, making it impossible to remove the plug while the circuit is complete, but necessitating that the plug be first lifted to interrupt the circuit, and then, lift it further to the horizontal position to unlock the plug before it can be removed. Thus, the weight of the plug with the assistance of the toggle spring tends to hold the receptacle in the locked circuit completing position and prevents its accidental removal therefrom without first deliberately lifting the plug up to the horizontal position.

Still a further object of this invention is to provide a plug receiving receptacle which has a rotatable disc having the plug socket therein, which extends slightly beyond the surface of the remainder of the receptacle, and thus, of a wall in which it may be mounted, thus, it making it easy to find the receptacle and insert it by feel even in the dark.

Still a further object of this invention is to provide a shock-proof locking receptacle whose external parts can lend themselves to any durable decorative material without diminishing the serviceability thereof.

With the foregoing and other objects in View, this invention comprises the combination, construction and arrangement of parts hereinafter set forth, claimed and disclosed in the accompanying drawings, wherein:

Fig. 1 is a side elevational view of the receptacle as mounted on a wall joist, with the receptacle still in closed position, although the plug has been partially inserted.

Fig. 2 is a top edge elevational view of Fig. 1.

Fig. 3 is a bottom edge elevational view of Fig. 1.

Fig. 4 is a sectional view on line 4 4 of Fig. 1.

Fig. 5 is a sectional view similar to Fig. 4, but with the plug fully depressed, but not yet rotated.

Fig. 6 is a side elevational view, omitting the near side frame plate of the receptacle, with the plug rotated to locked and to circuit completing position.

Fig. 7 is an exploded perspective view of the receptacle and of the plug.

Fig. 8 is a perspective view of the receptacle and plug mounted in a wall in operative position.

There is shown at I0 the shock-proof receptacle arranged to receive and lock therewithin the one prong electrical plug l l when the plug is in circuit completing position.

The electrical plug I I of this invention comprises an axially extending contact rod l2 inapertures sulatably supported concentrically within a contact sleeve it, contact sleeve |65 having an enlarged portion I5 through which electrical conductors I6 extend, the enlarged portion I5 being out away so that one of the conductors it may be secured as at il to the axially extendingrod I2, and the other conductor I6 is secured as at I8 to the enlarged portion i5 of the sleeve i4.

As a result of the cutaways 2li in the enlarged contact sleeve portion I5, the securing screws i1 and I8 are countersunk below the surface of the enlarged portion of the sleeve I5, and an insulating jacket 2|, of ceramic or other suitable insulating material, is slid over the enlarged sleeve portion i5 and secured thereto, as by a screw 22. The insulating jacket 2|, thus, provides a handle for manipulating the plug Il. The external end of the contact sleeve proper I3 is provided with a circumferential groove 23, and beyond the groove 23, there is provided a conically shaped end 23 on the contact sleeve I4, the sleeve Id having the axial contact rod I2 provided with a contact end 25 extending therebeyond and insulated from the sleeve |13 by the same insulating material that extends concentrically between the rod I2 and the sleeve I4, and maintains in insulated concentric relation.

The receptacle Il) comprises a pair of side frame members 30 and 3| of metal or other `conductive material secured together by means of stud bolts 32 passing through appropriate 33 in plate 3!) and threaded into suitably threaded apertures 35, in the other plate 3|, although obviously nuts could be provided instead of the threads in the apertures 33. The plates 30 and 3| are held in proper spaced parallel relationship to each other by means of sleeves 35 and a sleeve portion 3E, which act to space the plates in proper relationship to each other. Both plates 3G and 3| are provided with out-turned nanges 3l and 38, having suitable apertures 43 through which wood screws 4| may be inserted for mounting the receptacle I3 on a suitable support, such as, a joist, or the like 42, within a wall 55.

Journalled between conductor plates 30 and 3| is a socket disc 43 having a socket opening 44 of uniform diameter to receive the sleeve proper I4 therethrough, the diameter of the disc 33 being substantially equal to the length of the sleeve proper lll between the shoulder joining it to the sleeve enlargement I5 at one end, and a circumferential groove 23 at the other end, so that when the plug is inserted within the socket opening lili of the disc 43, the circumferential groove 23 will extend just beyond the inner end of socket opening 44. Radially aligned with the socket opening Mi at the inner end thereof is a transverse slot 45. The disc 43 has axle ends 43 extending therefrom and journalled in bearing openings 4l in the plates 30 and 3|.

The disc 43 has a link 3 integrally secured thereto at one end, and its other end is pivoted by a screw 43 between a bifurcated end 53 of a spring plunger 5| about which there extends a compression coil spring 52 biased within a U- shaped well 53 which is journalled by means of pins 55 in apertures 3|, resists the initial rotation of the disc, and then assists its final rotation. As one limit of rotation, the socket opening it extends in a horizontal position with the plug II in horizontal 55 in the side plates 30 and providing a toggle member which yieldably position when the device is mounted in a wall, as shown at 53 in Fig. 8. In this position, as also shown in Fig. l, a portion of the toggle member abuts against an inturned tongue 5l at one end of side frame plate 3|, this inturned tongue 5l having an extending tab 53 apertured as at and threaded to receive a stud screw 6| and hold a wall plate 52 in position thereon, a similar tab 57 and tongue 58 being provided at the other outer end of plate 3|.

Cooperating with the radial slot 45 of the disc 43 is the latch member 63 having 'bifurcated prongs 64 which are guided in guide slots 39 in the side frame plate members 3G and 3|, and a latch member E3 being provided with a compression spring 65 extending about the latch member plunger 65, and biased between the prongs 64 and an apertured sleeve 3'! secured by pins 68 extending through apertures l in the side frame plates 3B and 3|. In order to permit the plunger B5 to retract and compress the spring 55, a well l'I is provided in the supporting joist 42, although obviously the side frame plates 3|! and 3| could be made sufciently longer so as to avoid the necessity for the well 1|. Also, the well 1| could be omitted by either shortening the end of plunger 56, or reducing the depth of the disc slot 45, or both, thus shortening the length of the plunger travel so as not to exceed the length of the receptacle proper.

Extending inwardly from the prongs or bifurcated fingers Sli are projecting edges bevelled as at l2 and complementary to the conical end 24 of the contact sleeve |13, so that when the sleeve I4 is inserted through the socket opening i4 in disc 43, the conical end 2li will abut against the bevelled edges T2 to expel the fingers or prongs Eli from the radial slot 5 against the resistance of the spring B5. To prevent the prongs or fingers Bd from being spread apart by the action of the conical end 2li of sleeve I4, guide reinforcing plates 13 are secured on the outer surfaces of the side frame plates 3@ and 3| over the outer ends of the guide slot 69, and of a size so that the outer` edges of iingers or prongs 64 will still be in contact therewith when the latch member 63 has moved inwardly the maximum distance against the spring 65. The slots 69 and plates 13 thus act to guide the fingers or prongs 64 in their travel.

Between the lower portions of the lingers or prongs 64 and beyond the bevelled edges l2, as viewed from the outside of the receptacle, there is provided a bevelled deector plate ld having a deector of bevelled surface in axial alignment with the socket opening @t when the fmgers or prongs Bil are engaged and latched in the regular slot 45. If a small object such as a hair pin is inserted through the socket opening 44 and slips between the bevelled edges 12, it will be deflected by this deflector plate lli, rather than press thereagainst, and thus, serve to minimize the possibility that a foreign object would operate the same.

Extending from the sleeve portion 33 are a pair of prongs 'i5 spaced apart the proper distance so that they may fit into a circumferential groove 23 of a Contact sleeve I3 and prevent the contact sleeve Iii, and thus, the plug II from being withdrawn so long as they are in cooperative positionI These prongs i3 are contoured to the periphery of the disc e3 and lie closely thereagainst, a tab le extending on the other side of the sleeve portion 3S, tending to contact the periphery of disc 43, and thus, preventing any' pivoted movement or the plug locking prongs 15.

As will be apparent, insertion of the plug II into the receptacle I Will cause the sleeve I4 to slide through the socket opening 44, its conical end 24 abutting the bevelled edges 12 of ngers or prongs 64, will expel the latch member 63 from the radial slotl 45 permitting the disc 43 to be rotated by means of the plugv from the position shown in dotted line in Fig. 8 to the position shown in full line in Fig. 8. As this happens, the conical end 24 will move out from between the bevelled edges 12, and the latch member 63 will be held in retracted position by means of the ends 11 of prongs 64 abutting against the periphery of disc 43. The circumferential groove 23 will then enter between the plug locking prongs as the toggle member spring 52 is first compressed and then expands beyond itsl dead center to urge the disc to complete its rotation. The contact end 25 of the center contact rod I2 extends between and beyond the locking prongs 15, and comes into mechanical and electrical contact with a positive contact terminal 88 having a terminal tongue 8'I suitably supported in the path of the contact rod contact end 25, thus providing a limit for the rotation ofthe disc 43 in this direction.

This contact terminal 88 is supported on the outside of a pair of insulating plates 82 and B3, which are supported and secured by means of bolts or screws, 84 to apertures in the tab 51, already described on the plate 3l, andl a similar tab 85 at the other end of the same plate 3 I. The plate 83 is placed inside of the two tabs 5".' and 85 between the plates 38 and 3|, and the other insulating plate 82 is secured on the outside of these same two tabs 51 and 85. Both insulating plates 82 and 83, made of any suitable rigid insulating material, are provided with longitudinal slots 86 and 81. The contact terminal 8U is secured on the outer plate 82 by bolts and nuts 88 and 90, with its contact tongue 8| bent inwardly so as to point approximately toward the center of the disc 43, while the contact rod I2, when inserted through the socket opening 44 and rotated, will just extend through the slot 8B in the inner insulating plate 83 and come into abutting mechanical and electrical contact with the contact. tongue 8|, as clearly illustrated in Fig. 6. An electrical conductor 9| is suitably secured between the nuts 90 for providing the positive side of the circuit, and a second or negative electrical conductor 92 is secured by a nut and bolt 93 to the conductive side frame plate 3 I as by being secured on its flange 38.

In operation,A the receptacle I 0 will be mounted in awall 56, as shown in Fig. 8., with a portion of the disc 43 beyond the wall plate 62 extending beyond the surface of the wall 56, thus, making it easy to locate the socket opening therein. The plug Il will be inserted into the socket opening in the disc 43 in a horizontal direction, and then, rotated downwardly to the 'limit of its rotation, as shown in dotted lines in Fig. 8, thus, both locking the plug II in the socket opening and completing the circuit from the positive electric conductor 3| to the plug conductors I5, and back to the negative conductor 33.

As the plug II is inserted, the conical end 24 of the contact sleeve I4 abuts the bevelled inner edges 12 of the fingers or prongs 64 expelling the latch member 53 therefrom, and permitting the disc 43 to commence its rotation, the circumferential groove then entering between and locking contact end 25 of the Vmakes an electrical' within thelocking prongs 15, and 'finally the contact end 25 abutting against the contact tongue 8| to complete the circuit.

inasmuch as the contact sleeve I4 is in contact with the socket opening 44 of disc 43, it connection through the disc 43 and the conductive side plate to the negative conductor 92. Thus, contact is made with the negati-ve side of the circuit as soon as the sleeve enters the socket opening, and is not completed to the positive side of the circuit until after the disc has been unlatched, partly rotated to lock the plug in position, and then, completely rotated to make the positive contact. Before the plug I I can be withdrawn intentionally or accidentally, it must first be moved to rotate the disc 43 in the opposite direction, thus, first breaking the positive side of the circuit by moving the contact end 25 away from the contact tongue 8 I, then releasing the circumferential groove 23 of contact sleeve I4 from between the locking prongs 15, and then, finally withdrawing the same in the horizontal position of Fig. 8, and the latch 63 is simultaneously moved into latching position by its spring 65 as its fingers or prongs 64 re-enter the radial slot 45 to hold the disc 43 against accidental rotation.

Should a foreign object be inserted through the socket opening 44, as by a child, for instance, its entry will be resisted by the bevelled edges 12 of the lingers 64. If the object is too large to pass between these fingers, then, of course, it can never reach in far enough to reach the positive contact tongue, even though it may be strong enough to press and expel the latch member 63. If small enough to lit between the bevelled edges, it may also be weak enough to be deflected by the deiiector plate 14, and thus, prevent any accidental operation. Should the foreign object be of conductive material and happen to be of proper size and shape to actually unlatch the latching fingers 64 and rotate the disc, and iit between the locking prongs 15, such as when the foreign object may be a strong, thin darning needle, then if the foreign object should finally reach the internal contact or its contact finger 8I then the most that would happen would be that the circuit from the positive conductor 9| going through the end of the foreign object would be grounded through the disc 43 to the side plate 3l and the negative conductor 92, probably blowing the fuse, but in any case, avoiding any shock to the child inserting the foreign object.

Applicants receptacle is thus shock-proof against the insertion of any foreign object, and in addition, serves to lock the plug II in circuit completing position against accidental removal while the circuit is complete, necessitating the breaking of the circuit prior to the removal of the plug from the receptacle.

While the device has been shown and the structure described in detail, it is obvious that this invention is not to be considered as being limited exact form disclosed, and that changes may be made therein within the scope of what is claimed, without departing from the spirit of this invention.

Having thus set forth and disclosed the nature of this invention, what is claimed is:

1. In combination, a shock-proof locking electrical plug and receptacle comprising an axially extending contact rod, a contact sleeve insulatably supported on said contact rod having one end thereof spaced from an extending contact end of said contact rod, said contact sleeve having a circumferential groove thereabout adjacent said contact sleeve end, means for securing a separate electrical conductor to each of said contact rod and said contact sleeve, an insulating jacket providing a plug handle secured about said conductor securing means, and a conductive receptacle for said plug, a conductive socket disc journaled in said receptacle having a diametrically extending socket opening therethrough to receive said plug contact sleeve therein with its end extending beyond the inner end of said socket opening, a yieldable toggle member journaled in said receptacle and secured to said disc and yieldably urging it toward each limit of its rotation, means for locking said disc against rotation in the absence of said plug and operable by said plug for releasing said disc for rotation, plug locking means secured in said receptacle in the path of rotation of said end of said plug contact sleeve to t into said sleeve circumferential groove, a plug contact rod cooperating contact terminal insulatably supported in said receptacle in the path of said plug contact rod contact end to abut said plug contact rod contact end when said plug is locked in said socket and be yieldably urged against said contact terminal by said toggle means, said insulatably mounted contact terminal providing a positive terminal, and a negative terminal grounded to said receptacle and thus through said disc to said plug contact sleeve, whereby insertion of said plug into said disc socket opening expels said disc latch member permitting said disc and plug to rotate into plug lock cooperating position and then to contact completing position, and be held in contact completing position by said toggle means, said plug being thus locked against removal while in contact completing position, and to be rotated away from contact completing'position to plug releasing position and then to disc latching position as said plug is Withdrawn, and whereby a foreign object of suciently dissimilar shape will be noncooperative with said locking means, and a foreign conductive object of sufficiently similar shape to expel said disc latch member and rotate said disc to contact completing position will ground the circuit through said receptacle.

2. In combination, a shock-proof locking electrical plug and receptacle comprising an axially extending contact rod, a contact sleeve insulatably supported on said contact rod having one end thereof spaced from an extending contact end of said contact rod, said contact sleeve having a circumferential groove thereabout adjacent said contact sleeve end, means for securing a separate electrical conductor to each of said contact rod and said contact sleeve, an insulating jacket providing a plug handle secured about said conductor securing means, and a conductive receptacle for said plug, a conductive socket disc journaled in said receptacle having a diametrically extending socket opening therethrough to receive said plug contact sleeve therein with its end extending beyond the inner end of said socket opening, a yieldable toggle member journaled in said receptacle and secured to said disc and yieldably urging it toward each limit of its rotation, means for locking said disc against rotation in the absence of said plug and operable by said plug for releasing said disc for rotation, said disc locking means comprising a transverse slot in said disc radially aligned with said inner end of said socket opening, a latch member, and yieldable means urging said latch member into said disc slot, said latch member being expellable by said plug, plug locking means secured in said receptacle in the path of rotation of said end of said plug contact sleeve to fit into said sleeve circumferential groove, a plug contact rod cooperating contact terminal insulatably supported in said receptacle in the path of said plug contact rod contact end to abut said plug contact rod contactv end when said plug is locked in said socket and be yieldably urged against said contact terminal by said toggle means, said insulatably mounted contact terminal providing a positive terminal, and a negative terminal grounded to said receptacle and thus through said disc to said plug contact sleeve, whereby insertion of said plug into said disc socket opening expells said disc latch member permitting said disc and plug to rotate into plug lock cooperating position and then to contact completing position, to be held in contact completing position by said toggle means, said plug being thus locked against removal while in contact completing position, and to be rotated away from contact completing position to plug releasing position and then to disc latching position as said plug is withdrawn, and whereby a foreign object of sufciently dissimilar shape will be non-cooperative with said locking means, and a foreign conductive object of suciently similar shape to expell said disc latch member and rotate said disc to contact completing position will ground the circuit through said receptacle.

3. In combination, a shock-proof locking electrical plug and receptacle comprising an axially extending contact rod, a contact sleeve insulatably supported on said contact rod having one end thereof spaced from an extending contact end of said contact rod, said one end of said contact sleeve being conical in shape, said contact sleeve having a circumferential groove thereabout adjacent said conical contact sleeve end, means for securing a separate electrical conductor to each of said contact rod and said contact sleeve, an insulating jacket providing a plug handle secured about said conductor securing means, and a conductive receptacle for said plug, a conductive socket disc journaled in said receptacle having a diametrically extending socket opening therethrough toV receive said plug ccntact sleeve therein with its conical end extending beyond the irmer end of said socket opening, a yieldable toggle member journaled in said receptacle and secured to said disc and yieldably urging it toward each limit of its rotation, means for locking said disc against rotation in the absence of said plug and operable by said plug for releasing said disc for rotation, said disc locking means comprising a transverse slot in said disc radially aligned with said inner end of said socket opening, a latch member, and yieldable means urging said latch member into said disc slot, said latch member being expellable by said plug, the disc slot entering portion of said latch member having bifurcated fingers Whose adjacent edges are complementary to said conical end of said contact sleeve, plug locking means secured in said receptacle in the path of rotation of said conical end of said plug contact sleeve comprising a pair of contoured prongs adjacent the disc periphery spaced apart to :lit into said sleeve circumferential groove, a plug contact rod cooperating contact terminal insulatably supported in said receptacle in the path of said plug contact rod contact end to abut said plug contact rod contact end when said plug is locked in said socket and be yieldably urged against said contact terminal by said toggle means, said insulatably mounted lcontact terminal providing a positive terminal, and a negative terminal grounded to said receptacle and thus through said disc to said plug contact sleeve, whereby insertion of said plug into said disc socket opening expells said disc latch member permitting said disc and plug to rotate into plug lock cooperating position and then to contact completing position, and be held in contact completing position by said toggle means, said plug being thus locked against removal while in contact completing position, and to be rotated away from contact completing position to plug releasing position and then to disc latching position as said plug is withdrawn, and whereby a foreign object of suiiiciently dissimilar shape will be non-cooperative with said locking means, and a foreign conductive object of suiciently similar shape to expell said disc latch member and rotate said disc to contact completing position will ground the circuit through said receptacle.

4. In combination, a shock-proof locking electrical plug and receptacle comprising an axially extending contact rod, a contact sleeve insulat- -r ably supported on said contact rod having one end thereof spaced from an extending contact end of said contact rod, said contact sleeve having a circumferential groove thereabout adjacent said contact sleeve end, means for securing a separate electrical conductor to each of said contact rod and said contact sleeve, an insulating jacket providing a plug handle secured said plug into sai-d disc socket opening expells said disc latch member permitting said disc and plug to rotate into plug lock cooperating position and then to contact completing position, and be held in contact completing position by said toggle means, said plug being thus locked against removal while in contact completing position, and to be rotated away from contact completing position to plug releasing position and then to disc latching position as said plug is withdrawn, and whereby a foreign object of sufliciently dissimilar shape will be non-cooperative with said locking means, and a foreign conductive object of sufficiently similar shape to expell said disc latch member and rotate said disc to contact completing position will ground the circuit through said receptacle.

5.. In combination, a shock-proof locking electrical plug and a receptacle comprising an axially extending contact rod, a contact sleeve insulattact sleeve having a circumferential groove thereabout adjacent said conical contact sleeve end, means for securing a separate electrical conductoggle member journaled between said plates and secured to said disc and yieldably urging it toward each limit of its rotation, means for locking said disc against rotation in the absence means comprising a transverse slot in said disc radially aligned with said inner end of said socket openlng, a latch member, and yieldable means urging said latch member into said disc slot, said latch member being expellable by said plug, the disc slot entering portion of said latch to abut said plug contact rod when said plug is locked in said socket and be yieldably urged against said Contact terminal by said toggle means, said insulatably mounted contact terminal providing a positive terminal, and

1l tate said disc to contact completing rposition will ground the circuit through said receptacle.

6. In combination, a shock-proof locking electrical plug and receptacle comprising an axially extending contact rod, a contact sleeve insulatably supported on said contact rod having one end thereof spaced from an extending contact end of said contact rod, said one end of said contact sleeve being conical in shape, said contact sleeve having a circumferential groove thereabout adjacent said conical contact sleeve end, means for securing a separate electrical conductor to each of said contact rod and said contact sleeve, an insulating jacket providing a plug handle secured about said conductor securing means, and a receptacle for said plug comprising a pair of side frame conductive plates secured together in spaced parallel relation, outturned flanges on said plates providing receptacle mounting means, a conductive socket disc journaled between said plates having a diametrically extending socket opening therethrough to receive said plug contact sleeve therein with its conical end extending beyond the inner end of said socket opening, a yieldable toggle member journaled between said plates and secured to said disc and yieldably urging it toward limit of its rotation, means for locking said disc against rotation in the absence of said plug and operable by said plug for releasing said disc for rotation, said disc locking means comprising a transverse slot in said disc radially aligned with said inner end of said socket opening, a latch member, and yieldable means urging said latch member into said disc slot, said latch member being expellable by said plug, the disc slot entering portion of said latch member having biiurcated fingers whose adjacent edges are complementary to said conical end of said contact sleeve, and a foreign object deiiector plate mounted between said latch member fingers, plug locking means secured between said frame plates in the path of rotation of said conical end of said plug contact sleeve comprising a pair of contoured prongs adjacent the disc periphery spaced apart to fit into said sleeve circumferential groove, a plug contact rod cooperating contact terminal insulatably supported between said frame plates in the path of said plug contact rod contact end to abut said plug contact rod contact end when said plug is locked in said socket and be yieldably urged against said contact terminal by said toggle means, said insulatably mounted contact terminal providing a positive terminal, and a negative terminal grounded to said frame plates and thus through said disc to said plug contact sleeve, whereby insertion of said plug into said disc socket opening expells said disc latch member permitting said disc and plug to rotate into plug lock cooperating position and then to contact completing position, and be held in contact completing position by said toggle means, said plug being thus locked against removal while in contact completing position, and to be rotated away from contact completing position to .plug releasing position and then to disc latching position as said plug is withdrawn, and whereby a foreign object of sufficiently dissimilar shape will be non-cooperative with said locking means latch member iingers and will be deected from said latch member by said deflector plates, and a foreign conductive object of suiciently similar shape to expell said disc latch member and rotate said disc to contact completing position will ground the circuit through said receptacle.

'7. For use with a one prong electrical plug, a shockproof receptacle for the plug comprising a pair of side frame conductive plates secured'together, a conductive socket disc journalledV between said plates having a diametrically extending socket opening therethrough to receive a plug therein with its end extending beyond the inner end of the socket opening, a yieldable toggle member journaled between said plates and secured to said disc and yieldably urging it toward each limit of its rotation, means for locking said disc against rotation in the absence of the plug and operable by the plug for releasing said disc for rotation, said disc locking means comprising a transverse slot in said disc radially aligned with said inner end of said socket opening, a latch member, and yieldable means urging said latch member into said disc slot, said latch member being expellab-le by the plug, the disc slot entering portion or said latch member having bifurcated fingers, plug locking means secured between said frame plates in the path of rotation of said end of said plug contact sleeve, a plug contact cooperating contact terminal insulatably supported between said frame plates in the path of the plug contact end to abut said plug contact end when the plug is locked in said socket and be yieldably urged against said contact terminal by said toggle means, said insulatably mounted contact terminal providing a positive terminal, and a negative terminal grounded to said frame plates and thus through said disc to said plug contact sleeve.

8. For use with a one prong electrical plug, a shockproci receptacle for the plug comprising a pair of side frame conductive plates secured together, a conductive socket disc journaled between said plates having a diametrically extending socket opening therethrough to receive a plug therein with its end extending therebeyond the inner end of the socket opening, a yieldable toggle member journaled between said plates and secured to said disc and yieldably urging it toward each limit of its rotation, means for locking said disc against rotation in the absence of the plug and operable by the plug for releasing said disc for rotation, said disc locking means comprising a transverse slot in said disc radially aligned with said inner end of said socket opening, a latch member, and yieldable means urging said latch member into said disc slot, said latch member being expellable by the plug, the disc slot entering portion of said latch member having bifurcated ngers, plug locking means secured between said frame plates in the path of rotation of said end of said plug contact sleeve comprising a pair of contoured prongs adjacent the disc periphery spaced apart to nt into a plug circumferential groove, a plug Contact cooperating contact terminal insulatably supported between said frame plates in the path oi the plug contact end to abut said plug contact end when the plug is locked in said socket and be yieldably urged against said contact terminal by said toggle means, said insulatably mounted contact terminal providing a positive terminal, and a negative terminal grounded to said frame plates and thus through said disc to said plug contact sleeve.

WALTER H. WILSON.

Country Date Switzerland Oct. 14, 1912 Number

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