Patent GB-700433-A (GB)
Title: Improvements in and relating to electric lighting fittings
IPC: F21S2/00
Filed: 1952-01-30
Abstract: 700,433. Lighting fittings. BENJAMIN ELECTRIC, Ltd., and CAMPELL, H. G. (Benjamin Electric Manufacturing Co.). Jan. 30, 1952, No. 2502/52. Class 75 (4) [Also in Group XXV] An electric lighting fitting comprises a main elongated member 15, at least one further elongated parallel side member 16,17 and a cross member 18, 19 and holders 20, 21 carried by the members for supporting at least one lamp 22 transversely between the elongated members. The elongated members are formed by channels of equal length and of rectangular U-section joined end to end by readily connectible securing means and are secured to a flat surface with the base of the U in contact therewith. The readily connectible securing means comprises a lug 15e, Fig. 3, on the end of one channel which enters the end of the adjacent channel and a slot 15f for the passage of a screw into the corresponding lug on the adjacent channel. The two lugs do not occupy the whole width of the channel so that relative lateral movement of the channels is permitted. The ends of the elongated members are closed by box-shaped caps provided with lugs and slots. The elongated side channels 16, 17 are secured to the flat supporting surface by devices allowing initial lateral movement of the side channels to and from the main channel 15 and comprising a transverse slot 16a, Fig. 11, in the side channel covered by a plate 36 which has a hole 36a for a securing screw in line with the slot and which is slidably mounted on the channel by rivets 37 secured to the channel and passing through slots 36b in the plate. The lampholders 20 secured to the main channel 15 comprise cylindrical portions depressible against spring action into fixed portions. The lampholders 21 secured to the side channels 16, 17 do not have a depressible part and are of the type in which the insertion of the lamp causes a connection to be made between two terminals of the holder and also connects the lamp pin to the connected terminals. Each section of the main channel 15 carries housings 23 for the ballasts of the lamps mounted on that section, the housings being secured by clamping their end flanges by means of plates and bolts to inturned flanges at the mouth of the channel. The parts of the main channel 15 not covered by the ballast housings are covered by members 31, 32, 33 having upwardly flanged edges to embrace the edges of the channel and having rectangular openings to permit them to pass over the lampholders 20. Each section of the side channels is provided with a similar one-piece cover. The cross members 18, 19 are also of channel form and are detachably connected to the main and side channels by mechanical couplings comprising a rectangular member 38, Fig. 7, secured to the end of a cross member, its forwardly extending sides being bent back to form tongues 38a which enter slots 15c, Fig. 6, in the vertical wall of the side or main channel. Depressions 15d are formed in the channel adjacent the slots and serve to force the tongues 38a, through the slots on disconnecting the coupling. Some of these mechanical couplings are provided with electrical plug and socket connectors 39, 40, one being attached in an opening in the wall of the side or main channel, the other being secured in a rectangular opening in the member 38. In engaging a cross member with a main and side channel, the cross member is moved in a direction at right angles to the length of the main and side channels in the plane of the channels. The electrical wiring is housed in the side and main channels and in some of the cross members but does not extend directly between adjacent sections of the main channel, the electrical connection between adjacent main channel sections being effected indirectly by means of the electrical couplings associated with the cross members. Screens made of translucent or opaque, sound absorbent, light reflecting material in plane form or of open box-like grid construction may be suspended between and/or below the lamps. A translucent false ceiling may be supported above the screens. Specification 669,993 is referred to.