US2181050A

US2181050A - Lamp or plug and receptacle therefor

Info

Publication number: US2181050A
Application number: US130178A
Authority: US
Inventors: Earl R Evans
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-03-10
Filing date: 1937-03-10
Publication date: 1939-11-21
Anticipated expiration: 1956-11-21

Description

E. R. EVANS LAMP 0R PLUG AND RECEPTACLE THEREFOR Nom 21, 1939.

Filed March 10, 1957 Patented Nov. 21, 1939 UNITED srnrss LAMP on PLUG AND asoarraons rnennroa Earl R. Evans, Jackson Heights, N. Y. Application March. l0, 1937,Serial No. 130,178

3 Claims.

This invention relates to electric lamps and sockets or receptacles therefor, or in general to electric connectors of the plug and socket type.

An object of the invention is to provide a shockproof or safety socket and an improved lamp base or plug adapted to be readily inserted into said socket, the lamp base or plug and the socket being as simple and rugged in construction as the ordinary Edison screw plug or lamp base and socket. By shockproof is meant a socket in which the possibility of accidental shock from exposed live contacts when the lamp or plug is removed from the socket or receptacle, or from touching the contacts of the plug or lamp as it is inserted in or removed from the socket, is obviated or materially reduced.

Prior sockets or receptacles of this character have been oi a complicated construction or have not come into general use becai cfe they required a specially constructed plug or lamp base which could not be used'in connection with the standard sockets or receptacles already in general use to such a large extent that it would be impracticable to replace them. Li accordance with a further feature of the invention, the lamp base or plug of the connector embodying the .invention although incdiiied from the usual construction as required by the construction of the iinproved socket is also adapted for insertion in the ordinary Socket wherever the latter are alread installed.

Another object of the-invention is to provide lamp with a wedge-shaped contact of novel character.

Another object of the invention is to provide a socket or receptacle with movable insulating members adapted to be displaced by the :wedgeshaped contact of the cooperating lamp or plug.

A still further object of the invention is to provide, in a socket of the character described, a novel contact device or switch for connecting a contact or contacts of the socket to the supply conductors when the lamp or plug is inserted in the socket.

Other objects and advantages of the invention will be apparent from the following description oi thepreierred embodiments thereof shown on the accompanying drawing, wherein Fig. l is a longitudinal sectional View of a lamp base and socket or receptacle constructed in accordance with the invention;

Fig. 2 is a cross-section taken on the line 2 2 of Fig. 1;

Fig. 3 is a similar view taken on the line 3--3 of Fig. l;

. tached shell contact while obviating distortionof spring 22, a spring formed of a helix coiled into (o1. 17e-ass) Fig. 4 is a sectional detail taken on the line :iof Fig. 1; and Fig. 5 is a view similarto Fig. l of ya modified form of socket or receptacle, with the base of the lamp partly inserted in the socket.

Referring to Fig. 1 of the drawing, in accordance with the invention the lamp (or plug) I0 forming one element of the connector is provided with the conventional threaded shell contact il which in the case of a lamp is cemented to the lamp bulb in the usual manner, the end oi said shell contact being closed by a molded insert l2 carrying the center or tip` Contact i3. The contact I3 is shown as soldered at lf3 Vto one of the lamp terminal conductors it, the other of said conductors being connected to the shell contact Il.

Instead of the ordinary flat center contact, the contact i 3 projects from the-body of the lamp,- base and is preferably conical or'wedge-.Jhaped for a purpose to be described. As shown, the insert i2 which maybe of glass has a corresponding conical portion engaging and supporting' the contactmember i3, and capable of transmitting substantial inward Contact pressure to the at-v 5 the tip Contact. If desired, the contact member i3 may be shortened so that it does not cover all or any substantial part of the projecting portion of the insert i2, and the size, shape and arrangenient` of these parts of the base may be otherwise varied somewhat if the functions thereof .a pointed out hereinafter be borne in mind. The socket or receptacle forming the second'element of the connector comprises a casing orhous- 3- ing vi8 of any suitable character, preferably a one-piece molded shell of Bakelite, Textolite or bre, contact members i9 and 2@ adapted to cooperate with the contacts l l and i3 of the lamp base or plug, and movable or vseparable co-planar insulating members 2i arranged to shield the contact member 2i) from accidental contact with the fingers or a screw-driver, pencil or the like when the lamp or plug is removed from thesocket. In this modification of the invention, Ythe contact memberV i9 is intendedvtobe connected to the grounded side of the supply circuit so that there is no danger of shock or short-circuit al-v though it is exposed.

The insulating members 2l are made of any suitable insulating material and, in the preferred form of the invention, comprise two truncated parts engaging at the center of 'the socket andy held together by resilient means, ,such as a Wire circular shape With its ends fastened together or any equivalent means. Ihe two insulating members 2| are retained in the socket, as by the grooved end portion of an insulating block 23, the members being slidable in said block. The block 23 is also grooved to receive the spring 22 as shown in Figs. 3 and 4, and is so constructed as to prevent contact of the spring with the center contact member 20 in case the spring breaks after extended use and also to accurately center the members 2I t loosely in the transverse groove in the block 23 and, as clearly shown in Fig. 4, the tapered sides 24 of said members are at a greater angle with the base surface thereof than the sides of the groove in the block 23 in order to obviate wedging or binding of the same in said groove. As shown in Figs. 3 and 4, the groove in the members 2| or the block 23 is preferably discontinuous to prevent the spring 22 from turning in the groove.

The contact 253 is disposed in a central aperture in the insulating block 23 and opposite said contact, the ends of the insulating members 2l are cut away to form a tapered cavity 25 adapted to receive the end of the Wedge-shaped tip contact I3 of the lamp base whereby the shield members 2l will be spread apart as the lamp is inserted in the socket to expose the Contact member 23 (see Fig. 5). Thus the live contact of the socket is shielded when the lamp is removed from the socket but the lamp may be inserted in the socket and turned until contact is made with the tip of the lamp in the usual manner. While the specic form and mounting of the insulating members 2l shown have been chosen merely to illustrate a suitable construction which may be altered without departing from the scope of the invention, this construction has the advantages of ruggedness, durability and simplicity. In addition, it will be noted that in the event the spring 22 breaks, the socket will function as an ordinary unprotected socket.

The elements of the socket may be mounted in the casing I8 in any desired manner. As shown, the end of the contact member I9 is spun over the block 23 and also secured thereto by the terminal screw 29 extending through the shell contact into the block 23. The body portion ofl the casing I8 may be provided with internal ribs 3B (see Fig. 2) cooperating with the head of the screw 29 to prevent the shell from turning in the housing. The center contact 20 is preferably a round pin or stud urged toward the open end of the socket by a spring 3l and having its outer end drilled and tapped to receive the second terminal screw 32. There is thus, no possibility of a loose or high resistance joint between the terminal and the contact face, and since the spring 3l does not carry any current its resiliency will remain constant. The outer end of the contact member 2|] may be of substantially square cross-section, as shown in Fig. 2, so that it cannot turn in the supporting member 23. The block 23 with the elements of the socket carried thereby may be Withdrawn through the mouth of the casing I8 in order to attach the supply conductors 33 to the

terminals

32 and 29. If desired, means may be provided to lock the member 23 in the casing or the casing may be made of two interlocked sections according to usual practice.

If desired, the socket embodying the invention may be constructed to complete the circuit to the shell contact I9 upon the insertion of the lamp or plug in the socket so that accidental shock is avoided in the event that the shell terminal is not connected to the grounded side of the supply circuit. 'Ihis modification of the invention is shown in Fig. 5, which illustrates a construction similar to that shown in Figs. 1-4 except that the center contact member 23a, corresponding to the member 20 of Fig. 1, carries an insulating disc 35 supporting a circular contact ring 36 adapted to engage the end of the shell contact member I9a when the center contact member 23a is moved by engagement with the tip contact I3 of the lamp as it is inserted in the socket. The supply conductors 33 are connected to the terminals 32 and 31, the latter of which is connected to the contact ring 36. Thus the contact member 2Go is shielded and the contact member I9a is disconnected from the supply circuit until the lamp is inserted in the socket and turned until it firmly engages the contact member 2a. If desired, the contact ring 36 may be mounted on the block 28, corresponding to the block 23, and the contact shell lila may be movable to effect contact therewith as the lamp presses against the contact 20a. Various other modifications will occur to those skilled in the art and may be made without departing from the scope of the invention as dened in the appended claims.

I claim:

1. A connector having threaded plug and socket elements, said plug comprising a wedge-shaped center contact member projecting from the body portion of the plug and of substantial length, a contact member in said socket adapted to be engaged by said Erst-mentioned contact member and slidably mounted insulating elements covering said socket Contact member and constructed and arranged to be moved by the projecting wedge-shaped contact member of the plug to permit engagement thereof with said socket contact member as the elements of the connector are threaded together.

2. In a socket or receptacle, a center contact member, a grooved supporting member embracing the same, two insulating members disposed in the groove in said supporting member and movable to expose said contact member and resilient means engaging said insulating members to position the same with the inner ends thereof adja- Cent said contact member until spread apart to expose the latter.

3. In a socket or receptacle, a center Contact member, separable co-planar insulating members shielding the contact surface of said contact meinber and mounted for transverse opposed movement in said socket or receptacle, and resilient means engaging said insulating members and tending to hold them together.

EARL R. EVANS.