Patent GB-732057-A (GB)
Title: Improvements relating to spot lights
IPC: F21S8/02
Filed: 1952-06-30
Abstract: 732,057. Adjustable spot-light supports. EDISON SWAN ELECTRIC CO., Ltd., and ANSELL, K. W. Sept. 24, 1953 [June 30, 1952], No. 16403/52. Classes 75 (3) and 75 (4). An adjustable bracket assembly for supporting a spot-light comprises a bracket adapted to carry a light source and concentrating means and supported in a housing by first and second members guided in paths relative to the housing so that when the bracket is exposed movement of the first member along its path rotates the bracket about the second member to vary the inclination of the bracket relative to the housing axis until the bracket is parallel to said axis and continued movement of the first member along its path causes the second member to move along its path to retract the bracket into the housing and adjusting means are provided to maintain the first member at any selected point on its path. As shown in Fig. 2, a bracket 16 mounting a shade 2 accommodating a lamp 3 (embodying a reflector) in a lamp socket 1 is rotatable relative to the housing 4 by movement of a first pin 36 on the bracket in an arcuate slot 39 in a wall of the housing 4 and centred on a second pin 37 on the bracket located at the lower end of a straight slot 40 in the wall of the housing and when the bracket is parallel to the axis of the housing, it is retracted further into the housing, the pin 36 then being guided along a straight slot 38 in alignment with the slot 40 along which the pin 37 moves. The housing 4 is secured to a circular plate 41 retained on a mounting plate 5 by four grooved wheels 42 and rotated by turning one wheel provided with a knob 44. The bracket is retained at any angle of elevation as by a spring-pressed pair of friction washers on the pin 36 and sandwiching the wall of the housing. As shown in Fig. 1, the bracket 16 is pivotally mounted by the first member, in the form of a tube 20 passing through the bracket 16, on a carriage 15 moved rectilinearly up and down in the housing 4 by a lead screw 14 mounted in brackets 26, 27 in the housing and co-operating with a nut 17 on the carriage. Upward movement of the carriage 15 from the lowest position as shown causes a cam follower 22 consisting of a length of tube connected to the limbs of the bracket 16 to move in a cam slot 21a in a bracket 21 secured to the housing, thereby rotating the bracket until its axis is parallel to the housing axis ; and continued movement of the carriage retracts the bracket and lampshade into the housing. The carriage 15 is constituted by an M-shaped strip whose legs are bent first inwards and then parallel to the main portions of the legs to embrace the bracket 16 and receive the pivot tube 20. The nut 17 is secured in the re-entrant external angle of the M. The housing 4 is mounted on a plate 5 having a central aperture 9 and mounted e.g. over a hole in a ceiling 7, the plate 5 having a circular groove 34 of wide V-section engaged on its inner face by the flared mouth 28 of the housing held in place by angle pieces 35 spot welded to the outer groove face. When fitted horizontally, e.g. in a hole in a wall, the housing is clamped to the mounting plate. The housing is closed at one end by a flat disc 25 stood away from the end of the cylindrical wall by joggled angle members 31 and to increase the height of the housing a subsidiary portion 24 is added provided at one end with tabs 29 spot welded to the inner wall and adapted to engage frictionally the inner wall of the main housing portion 23. The housing may be pushed around by knobs 13 of the lead screw, or by means of frictionally engaged wheels or discs. The Provisional Specification describes a combined friction, pinion and clutch device for alternately rotating the lead screw and the housing about its axis, and the clutch may be dispensed with and a conical form of friction pinion used permanently in connection with the lead screw and axially movable to rotate the housing. The housing may also be rotated by a toothed or friction pinion disengageable from the bracket adjusting means to engage the periphery of the aperture of a plate mounting the housing.