Patent GB-1177332-A (GB)
Title: A Bulb Holder Assembly
Inventor: CIBIE PIERRE
IPC: F21V19/00
Filed: 1968-03-20
Abstract: 1,177,332. Lampholders. P. CIBIE. 20 March, 1968 [7 April, 1967], No. 13444/68. Heading H2E. [Also in Division F4] A bulb-holder assembly comprises a bulb L, supported in a central connector 20; a reflector 1; a hook-on ring 10, of J-shaped cross-section, arranged concentrically with the reflector opening; a case 30 surrounding said central connector and co-operating therewith to allow sliding movement in the axial but not the radial direction; and an outer sheath 50 surrounding said case, and enclosing a spring 40, so that rotation of the sheath 50 in one direction first causes axial retraction of the connector, and then entrains the connector and casing in said rotation. The bulb includes a double-fitting flange 3, having a centring peg 4 which engages in notches 1b and 11ain the reflector flange 1a and the hook-on ring 10 respectively, the flange 3 having a rim 5 carrying elements 5a which bear against the longitudinal edge of the flange 1a. The central connector 20 comprises a barrel 21 in which are terminals 6a; a central cylindrical part enclosed by walls 22; a radial shoulder 23; and peripheral area 24. The surrounding case 30 comprises a base 31, a hollow portion 32 and a front peripheral area 33. The peripheral areas 24 and 33 constitute interengaging projections and recesses allowing relative axial but not radial motion (Fig. 3, not shown). Outside the area 33, pegs 34 are provided for engagement with bayonet slots (13), (Fig. 4, not shown), in the hook-on ring 10. The case 30 is surrounded by a handling sheath 50, comprising a base 51, and first and second annular skirts 52 and 53, slidable on the part 32 of the case 30, there being a spring 40 in the space between the case 30 and sheath 50. The central connector 20 extends through openings in the bases 31 and 51 respectively of the case 30 and sheath 50. In the latter are three peripheral slots 54, through which extend three hooked pins 35 which engage a complementary raised area 52a of the skirt 52. Three radial pegs 25 prevent the spring 40 ejecting the connector 20 by bearing against three helical ramps or threads 55 on the rim of the opening in the base 51, said threads having a circumferential length at least equal to that of the slots 54. In the inoperative position the pegs 25 are positioned at the base of the ramps 55. If the sheath 50 is rotated in the direction f (Fig. 5a), it immediately entrains the connector 20 and case 30, by the pins 35 abutting against the edges of the slots 54. Rotation in the opposite direction causes the pegs 25 to traverse the ramps 55, so retracting the connector 20 before the pins 35 abut the other edge of the slots 54, after which entrainment occurs. In operation, the composite assembly L-20-30-40-50 is presented to the reflector 1 and ring 10, and the assembly is turned in direction f against the reflector, so that the pins 34 engage the bayonet slots (13). Further rotation aligns the peg 4 with the notches 1b and 11a the spring 40 then causing the connector 20 to move forward so that the peg 4 enters the notches. To separate the assembly, the sheath 50 is rotated in the opposite direction, so that the pegs 25 mount the ramps 55. The retraction so caused releases the peg 4 from said notches, and further rotation releases the bayonet engagement. The elements 20, 30 and 50 are preferably of a pliable plastics material, and the hook-on ring may be attached to the reflector flange 1a by clamping, crimping, or other means: