US2890435A - Electric lamp sockets - Google Patents

Description

Filed Aug. 11, 1955 INVENTOR:

CLARENCEWLLANS HEATH,

BY RAD-Z 46 PM A TTORNEY- United States Patent 2,89,435 Patented June a, 3959 fiice 2,890,435 I ELECTRIC LAMP SOCKETS Clarence Willans Heath, Bleasby, England, assignor to United-Carr Fastener Corporation, Cambridge, Mass, a corporation of Delaware Application August 11, 1 955, Serial No. 527,740

Claims priority, application Great Britain August 12, 1954 1 Claim. (Cl. 339-255) This invention relates to electric lamp sockets of the kind comprising a housing adapted to receive the base of the lamp and a spring loaded contact adapted to make electrical engagement with a base contact of the lamp.

It is an object of the invention to provide a socket having an improved form of spring loaded contact and improved means of attaching an electrical lead or leads thereto.

According to the present invention an electric lamp socket of the kind referred to is provided with a spring loaded contact including a metal shank portion slidable in a member of insulating material which closes one end of the housing, the shank extending inwardly of the housing and being provided at its free end with means for making electrical contact with the base contact of an inserted lamp, and means for locating one end of the spring which serves to urge the shank towards its inward position, the opposite end of the shank being formed with means limiting the inward movement of the shank and also serving for anchoring an electrical lead or leads.

The spring loaded contact may be formed of sheet metal bent into tubular form, the free end of the inner portion having an integral lug or flange which serves as an abutment for the adjacent end of the coil spring and also forms the contact means for engaging the base contact of an inserted electric lamp. The free end of the outer portion of the shank may have an integral extension which is bent to form a substantially cylindrical sleeve or socket having a bore extending transversely of the longitudinal axis of the shank and adapted to receive a plug like member for anchoring an electrical lead or leads.

To enable the invention to be fully understood it will now be described with reference to the accompanying drawing, in which:

Fig. 1 is a sectional side view of a socket according to one embodiment of the invention;

Fig. 2 is a view partly in section of a plug member for anchoring an electrical lead or leads to the socket;

Fig. 3 is a side view of the contact illustrated in Fig. 1 but taken at an angle of 90 and showing a lug or flange before it is bent downwardly to locate the spring;

Fig. 4 illustrates in developed form a blank from which the contact is formed, and

Fig. 5 is a fragmentary view of a modified form of contact.

As shown in the accompanying drawing an electrical lamp socket includes a sheet metal housing 1 shaped to receive the base of a lamp (not shown), the wall of the housing being formed in known manner with bayonet joint recesses 2 for engagement by laterally projecting pins on the lamp base, the inner end of the housing is closed by an end member 3 consisting of a plug of insulating material secured in position by indentations 4 and an inturned flange 5.

The end member 3 is formed with a central bore 6 in which a spring loaded contact 7 is slidably mounted. As shown the contact is formed of sheet metal bent to provide a tubular shank 8 extending through the bore 6 inwardly of the housing and formed at its inner end with an outwardly projecting integral lug or flange 9. The contact is urged inwardly of the housing by a coil spring 10 whose opposite ends abut the adjacent face of the end member 3 and the lug or flange 9.

The outer end of the contact which projects outwardly of the end end member 3 is bent to provide a substantially cylindrical sleeve 11 adapted to have an electrical lead or leads anchored thereto. The lead or leads may be anchored by means of a hollow plug like member 12 through which the bare ends of the lead or leads is or are threaded from the wider or hell mouthed end, the ends of the lead or leads being bent back to extend over the outer surface of the plug whereby when the plug is inserted into the sleeve 11, the bare ends of the lead or leads will be clamped between the outer face of the plug and the inner face of the sleeve.

In assembling the parts of the socket, the contact with the lug or flange 9 unbent, i.e. in the position indicated in full lines in Fig. 3, is inserted through the bore 6 in the end member. A coil spring 10 is then inserted over the inwardly extending portion of the shank 8 and the lug or flange bent downwardly to the position shown in Fig. 1 and as indicated in broken lines in Fig. 3. It will be noted that in its bent position the lug or flange 9, projects radially outwardly and forms an abutment for the adjacent end of the spring ltl whose opposite end abuts the inner face of the end member 3 whereby the spring tends to urge the contact inwardly of the housing and provides a resiliently mounted central contact for engagement with the base contact of an inserted lamp. The outer portion of the contact being of greater overall size than the shank 8 limits the inward movement of the contact.

The blank from which the contact 7 is formed is shown in Fig. 4. In forming the contact the blank is bent or curled about a longitudinal centre line to form a tubular shank 8, the longitudinal edges of which are pressed into close abutting relation and the ends of the blank remote from the lug 9 is bent or curled about a transverse centre to form the sleeve 11. The side portions of pins 9a of the lug 9 may be bent inwardly to underlie the central portion of the lug or flange, the free edge of which when bent downwardly then projects outwardly of the shank 8 and forms an abutment for the spring while the central portion of the lug or flange constitutes contact means for engagement with the base contact of an inserted lamp.

According to the modified form of contact illustrated in Fig. 5 the end of the shank 8a is formed with oppositely disposed lugs 8b which are adapted to be bent outwardly and downwardly over the adjacent end of the coil spring 10. In this case the upper rounded portions of the lugs constitute the contact means for engaging the base contact of an inserted lamp.

It will be understood that the lead or leads may be connected to the shank 8 by any means other than that described.

I claim:

A contact member for slidably extending through an apertured insulating base into an electric lamp socket and for being held in operative position within such socket by a coil spring, said contact being made from a single sheet metal blank and comprising a folded shank portion formed into a tubular cross section, a flange portion integrally connected at one end of the shank portion in hinged relation thereto and being adapted to be disposed substantially normal to the axis of the tubular shank portion and is provided with both a contact sur- 3 face for engaging a contact on a lamp base inserted into the socket and an oppositely directed surface for engaging a coil spring disposed around the shank for urging the contact surface into position in the lamp socket, and at the other end of the shank a portion normally formed to provide a tubular socket before assembly with a lamp socket and with its axis substantially normal to the axis of the shank and a diameter greater than the diameter of the shank portion providing shoulders adjaccnt the shank portion for engaging an outer face of the lamp socket base to cooperate with the flange portion to assemble the contact member with a lamp socket, said tubular socket also being adapted to receive an external connection and a cylindrical wedge for securing said connection therein,

References Cited in the file of this patent UNITED STATES PATENTS 399,465 B ainbridge Mar. 12, 1889 1,392,176 Koenig Sept. 27, 1921 1,803,709 Johnson May S, 1931 1,885,467 Neulner Nov. 1, 1932 2,303,836 Gordon Dec. 1, 1942 2,451,800 Buchanan et a1 Oct. 19, 1948 2,470,280 Ackerman May 17, 1949 2,559,174 Skony July 3, 1951

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