US 3864001 A
A lamp socket has a pair of diametrally opposed grooves leading to notches towards the open end thereof. Each groove receives a folded over contact strip adapted to receive the flat shank of a miniature lamp, the free ends of the strips protruding outwardly through the notches and serving as bayonets to grip and make contact with a circuit-carrying plate.
Claims available in
Description (OCR text may contain errors)
United States Patent 1191 Millet 51 Feb. 4, 1975 1 LAMP SOCKET  Inventor: Jean Joseph Millet, Besancon,
France  Assignee: S.O.C.O.P. S.A., Besancon, France  Filed: Oct. 18, 1973  Appl. No.: 407,673
 Foreign Application Priority Data Novv 3, 1972 France 72.39059  U.S. Cl 339/127, 339/217 S  Int. Cl H0lr 13/46  Field of Search 339/17 D, 59 13,127,144,
 References Cited UNITED STATES PATENTS 2,595,188 4/1952 DelCamp 339/17 D Loesch 339/17 D X Heath 339/17 D Primary Examiner-Richard E. Moore Attorney, Agent, or Firm-Robert E. Burns; Emmanuel J. Lobato; Bruce L. Adams  ABSTRACT A lamp socket has a pair of diametrally opposed grooves leading to notches towards the open end thereof. Each groove receives a folded over contact strip adapted to receive the flat shank of a miniature lamp, the free ends of the strips protruding outwardly through the notches and serving as bayonets to grip and make contact with a circuit-carrying plate.
4 Claims, 7 Drawing Figures PATENTED 41975 SHEET 10F 2 FIGA- PATENTEDFEB 4197s 3.864.001
SHEET 2 OF 2 K FIG-.6
LAMP SOCKET The invention relates to lamp holders and is particularly concerned with a socket for a miniature lamp having a flat stem.
There are numerous types of lamp sockets, in particular intended to be mounted on the instrument panels of motor vehicles or aircraft. The necessity of rapid visual control for achieving the correct operation of engines compels the designers to place several indicator lights in a restricted space, each indicator light having to be able to light up or go out according to various requirements.
The currently available types of lamp sockets have a certain number of drawbacks; most of them have only two points of electric contact with the circuit allowing only a positive or negative action. In addition, the reliability of this contact is subject to the quality of.resilience of the metal used without any additional force completing the spring action obtained at the time of shaping.
These difficulties are shared by a known arrangement, which comprises two pairs of electric contacts outside the lamp. The spring action of the metal contacts is solely directed towards the lamp by pressure exerted on the stem of the lamp in the vicinity of the contact points.
According to the invention the former difficulties are avoided. For this purpose there is provided a socket for mounting a miniature lamp having a flat stem, the socket being adapted to be mounted in an aperture of a thin plate having diametrally opposed electrical con ductors at the periphery of the aperture on at least one side of the plate, the socket being electrically connected to the conductors by contact means which detachably mount the lamp and electrically connect the conductors on the lamp stem to the plate conductors, said contact means comprising two pairs of resilient contacts each pair being formed by a spring strip folded into the general configuration of a flattened V having sides and free end parts, the sides of each V being located in a peripheral recess in the socket and the free end parts of each V being bent externally of the socket to form a bayonet for gripping the plate and making electrical connection with a plate conductor.
The main advantage achieved by the invention re sides in the gripping action on the plate, on either side of the latter, obtained by the bayonets formed by the two bent ends of each pair of electric contacts, thus, these bayonets ensure the electrical contact by either side of the plate carrying the circuits.
This gripping is effective to such an extent that the socket thus produced may be used on a flexible plate with complete reliability of the electrical connections.
Another advantage resides in the simplicity of manufacture of the electric contacts which may be obtained by a single cutting operation followed by several shaping and folding operations.
The mass manufacture of resilient contacts makes it possible to obtain a particularly advantageous cost price.
In addition, the mounting of the resilient contacts in the socket is extremely simple, since it is sufficient to push them into peripheral slots or grooves in the socket, and having a resilient tab of each contact bearing against the upper edge of the corresponding grooves to block the contact in the appropriate position.
Conversely it is sufficient to press on this resilient tab, disengaging it from the rim against which it bears, for easily removing the resilient contact from the socket.
Another advantage of the resilient contact resides in the presence, on the inner part, of the V, of two inwardly folded lateral tongues which bear against internal ribs on the socket and prevent any lateral displacement of the contact, particularly in the vicinity of the bent part forming the upper member of the bayonet ensuring the electrical contact with the plate supporting the circuits.
In addition, below these tongues, the same part of the V comprises two thin plates bent perpendicularly to the side, which elastically grip one of the flat sides of the stem of the lamp with its conductor, ensuring the electrical connection between the circuits and the lamp. Said connection is thus made independently of the fre quently irregular shape of the stems of miniature lamps, owing to the accentuated convexity of said tongues and to their great elasticity.
An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a diagrammatic sectional view of the lamp socket with a lamp engaged therein;
FIG. 2 is a sectional view ofthe socket with a resilient contact showing the bayonet gripping of the plate for supporting the electric circuits;
FIG. 3 is a side elevational view of the socket;
FIG. 4 is a top plan view of the socket showing the location of a resilient contact;
FIG. 5 shows a resilient contact before folding;
FIG. 6 is a side elevational view of a contact folded into a V-shape; and,
FIG. 7 is a plan view of the contact, looking from above FIG. 6.
FIGS. 1 to 4 show the socket fitted with only one of the two symmetrical contacts.
FIGS. 5 to 7 illustrate a resilient contact able to be mounted in either of the symmetrical diametrically opposed grooves in the socket.
Reference is made to all of FIGS. 1 to 7.
The socket 1 for a miniature'lamp is formed of an insulating material and is hollow. The socket 1 comprises a collar 2 extending outwardly from a substantically cylindrical part 3 between the ends of this part, and supports two identical resilient contacts 9, 10 arranged symmetrically inside the socket 1, intended to ensure the electrical connection between a lamp and circuits supported by a plate A.
Part 3 has two diametrally opposed notches or cutouts 4,5 extending from one end of this part to the collar 2. In cavity 6 of the socket l are two corresponding bayonet slots for'fixingsocket l by a turning movement.
Two lateral tongues 12,- symmetrical with respect to the longitudinal axis of the contact 9, are folded inwards so as to form lugs for locating the contact 9, 10 in the cavity 6 of the socket l, the tongues l2'bearing against an internal rib 17, 18 in the socket such that there is no corresponding movement of the lower part of the inner side of the contact 9, 10, when the bent part 11 is resiliently displaced.
Located under the tongues 12, on the same part of the contact 9, 10 which, folded over in V- configuration, forms the side located inside the cavity 6 of the socket l, are two thin plates 13, bent perpendicularly to the plane of said side and arcuately shaped such that inwardly bent convex points 13a, 13b located opposite each other on either side of the stem of the lamp, ensure an excellent contact when said thin plates 13 elastically grip the flat sides of the stem with their conductors.
A rib 14 stamped between these thin plates 13, serves to strengthen said inner side and of the contact and to guide the lamp stem.
The outer side 16 of the contact is folded such that the V it forms with the inner side 11 acts both to hold a lamp in the cavity 6 and to grip the plate A and the electric circuits thereon.
In other words, the bayonet ensuring the electrical contact with the circuits is formed by the superposition of the two bent ends 11, 16 of the two sides folded over onto each other.
A resilient lug 15 cut out and bent outwardly from the outer side of the contact ensures the positioning of the contact 9, 10 in the groove 7, 8 of the socket by abutting against the top of said groove. The bent end 16 of the contact rests in a notch in the collar 2, being retained in said notch by its curved shape and by the 4 gripping surfaces, without in any way compromising the efficiency of the socket. The simplicity of the resilient contacts and their reduced bulk make it possible to produce a socket for a lamp with a quadrangular stem having two different filaments.
What is claimed is:
l. Miniature lampholder, comprising a socket for mounting a miniature lamp having a stem. means on the socket for mounting it in an aperture ofa plate. and at least two contact means for detachably mounting the lamp in the aperture and electrically connecting conductors on the lamp stem to plate conductors. each contact means comprising a spring strip folded into the general configuration ofa flattened V having inner and outer sides and free end parts thereof, the sides of each V being located in a peripheral recess in the socket and the free end parts being bent externally of the recess to form a bayonet for gripping the plate and making electrical connection with a plate conductor.
2. Lampholder according to claim 1, wherein the socket has, at an upper, open part for receiving the stem of the lamp, a cylindrical part including two diametrically opposed cut-outs and a collar at which said cut-outs terminate, the outwardly bent end of each resilient strip extending through said cut-outs and the bent end of each outer side bearing against the collar such that the socket introduced into the aperture in the plate bears by the collar of the socket, through the end of the outer side, against one of the sides of the plate.
3. A device according to claim 2, in which each inner side of the resilient strip comprises, below the outwardly-bent end, two inwardly-folded lateral tongues, the socket having longitudinal grooves therein for guiding said tongues against the inner edges of said grooves to prevent movement of the lower part of inner sides of said contacts corresponding to resilient displacement of said bent ends.
4. A device according to claim 3, in which the inner side of each resilient strip includes two thin plates bent perpendicularly to the plane of the side to a convex shape adapted to resiliently grip one of the flat sides of the stern of a lamp with its conductor, and a rib between said thin plates reinforcing said side.