Patent GB-713465-A (GB)
Title: Improvements in or relating to electric lampholders
IPC: H01R33/08
Filed: 1951-12-13
Abstract: 713,465. Lamp caps and holders. PHILIPS ELECTRICAL INDUSTRIES, Ltd. Dec. 13, 1951, [Dec. 16, 1950.] No. 29190/51. Class 38 (1). A lampholder comprises a rotor and a stator each part being provided with lugs or cam surfaces which co-operate with those on the other part so that on rotation of the rotor by rotation of a lamp cap positioned in the holder, the rotor and/or the stator is/are moved in a direction parallel to the rotor axis. The axial movement is produced in a direction towards the lamp which is thereby retained in the holder. In the construction, Figs. 1-3, a stator 1 has a circular ridge 3 on its rear side provided with a pair of diametrically opposite recesses 4, whereby a pair of lugs 5 are formed. The rotor 6 has a larger diameter portion 8 formed with a pair of lugs 9 and is rotatable within an aperture 2 in the stator. In use, the lamp pins 12, e.g. at one end of a doubleended tubular lamp, are introduced through an entry 13 in the stator into a slot 7 in the rotor, and the rotor is turned through 90 degrees from the position shown whereby the lugs 9 move off the lugs 5 into the recesses 4 under the action of a spring 10 and the front of the rotor moves forwards to engage the lamp end. Since the other end of the lamp is fixed by another such holder, or otherwise, the forward movement of the rotor serves to clamp the lamp in position between its ends. In the clamped position the pins 12 engage the holder contacts 14. In another construction, Fig. 5, a cup-shaped stator 26 has three circularly arranged extensions 27 slidably extending through apertures in a fixed holder part 21. A pair of cavities 28 in the bottom of the stator receive a pair of lugs 25 on a rotor 23 whose front face is slotted at 24 and'is rotatable in an aperture 22 in the part 21. The lamp pins 31 are introduced into the slot 24 through an opening 33 in the part 21, and the extensions 27 do not then protrude beyond the front of the latter. On rotation of the lamp through 90 degrees, the lugs 25 enter the cavities 28 under the force of the spring 29 and the extensions 27 move forwards to embrace the lamp cap 32 as shown in Fig.  5  (the lamp actually being shown removed from the holder). In a construction Fig. 7 (not shown) embodying features of the two constructions described, both the rotor and stator move axially to clamp against and embrace, the lamp end, respectively. The extensions 27 may alternatively form resilient earthing contacts. According to the construction of Figs. 8, 9, 12, an insulating housing or stator 41 has a pair of lugs 48 on the edge of an aperture 42 which receives a rotor 45 having lugs 47. The lamp pins are inserted through an opening 60 in the front face of the housing 41 into the rotor slot 46, and initially the stator lugs 48 are on the higher parts 6I between the rotor lugs 47. On rotation of the lamp a slight resistance of the spring 49 must be overcome as the lugs 47 slide over the lugs 48 so that the rotor snaps into a position in which its lower parts 62 engage the lugs 48, the rotor thus also moving forwards to engage the lamp end. The rotor 45 includes a U-shaped earthing strap 6 3  having parts 6 4  which engage the lamp and a rear end which engages the spring 49, the rear end of the spring abutting a metal plate 6 5  connecting flanged tubes 44 through which fixing means pass. A holder for a lamp having a single central contact pin, Figs. 15, 16, 18, 20-22, comprises an insulating housing 71 with a lamp cap entry 75 leading to an aperture 72. A conical ridge 74 having two lugs 78 surrounds the aperture 72 and co-operates with a rotor 76 having a pair of recesses 79. The rotor has a cavity 90 extending from its rear face which receives a spring 77 and a pair of contacts 92 urged thereby through an insulating disc 96. The contacts 92 have half-moon shaped plates extending through a slot 91 in the forward end of the cavity 90 and strips 93 extending through the cavity and across the rear side of the rotor to form contacts 94 engageable by a holder contact 8 4 . The lamp cap comprises a hood 97 carrying a non-circular insulating block 100 slotted at 107 and secured by a flanged tube 103, serving as a lamp contact to which a lamp wire 105 is soldered. On introduction of the lamp to the holder the narrower part of the block 100 passes with small clearance through the entry 75 into the aperture 72 and the contacts 92 enter the slot 107. In this angular position of the rotor the recesses 79 do not receive the lugs 78, and the lamp is not connected in circuit since the holder contact 8 4  is not in a rotor groove 95 containing a contact 94. On rotation of the lamp through 90 degrees a contact 94 engages the contact 8 4  and the recesses 79 receive the lugs 78, the rotor thus moving forwards so that the full pressure of the spring 77 is exerted on the lamp through the contacts 92, 103. Figs. 23, 24 (not shown) illustrate diagrammatically a projection lamp having a contact cap only at one end, that end being held in a holder according to the invention, the other end abutting a fixed cup. Another construction for a single-ended lamp having a bayonet cap 122, Fig. 26, comprises a tubular rotor 123 carrying a pair of lamp engaging contacts I25 extending through a partition I24. The lower edge of the rotor has a pair of shallow recesses I33 and deep recesses I32 which alternatively co-operate with a pair of lugs 131 on a ridge 130 on a base I28. The base has a pair of spring plunger contacts I36 and is connected to the rotor by a cap I34 screwed to the ridge 130. On introduction of the bayonet lamp pins I27 into grooves I26 in the rotor the latter has a position (displaced 9o degrees from that shown) in which the deep recesses 132 receive the lugs 131, the other end of the lamp having first been positioned in the resilient support 138. The lamp is then turned through 9o degrees so that the lugs 131 are received by the shallow recesses 133 and the rotor is thereby raised. In this position contact is made with the lamp through the contacts 136, 125. Specifications 691,977 and 691,980 are referred to.