GB891092A - Improvements in or relating to the alignment of lamps with reflectors - Google Patents

Abstract

891,092. Mounting lamps relative to reflectors. KODAK Ltd. June 27, 1960 [June 26, 1959], No. 22433/60. Class 75(4) [Also in Group XL(b)] An energized lamp is aligned accurately with a reflector by causing relative movement between the lamp and reflector from a first extreme position to a second, detecting photo-electrically at a predetermined locus the light transmitted and storing a signal representing the maximum intensity encountered, causing return relative movement of the lamp and reflector from said second to said first position, comparing the light transmitted during the return movement with said stored maximum and stopping the movement when the intensity equals said maximum. The procedure is carried out in three co-ordinate directions, after which the lamp is fastened to the reflector in the final relative position, for example, by soldering or welding as described in Specification 891,091. The relative movements are effected by the arrangement shown in Fig. 1 in which the lamp 34 is moved relative to reflector 40, back and forth in a first direction by rotation of shaft 10 carrying a cam 15 engaging a follower 36 bearing on the lamp (the lamp being supported in a spring-loaded holder), and the reflector is moved relative the lamp in a second direction by rocking frame 62 (to which the reflector is secured) about pivots 64 and in a third direction by rocking plate 58 about pivots 60 in frame 62. The last two movements are effected by rotation of two further shafts (not shown in Fig. 1) which together with shaft 10 are rotated by motor 20. The shafts each carry a magnetic brake, such as 27, on shaft 10, by means of which they are normally held in initial positions and then in succession released and finally stopped in accordance with the light intensity measurements made by photo-electric cell 42. In the control circuit associated with the cell, Fig. 6 (not shown), the cell output is applied to charge a capacitor through a diode so that during the forward part of a movement the capacitor charges to and remains at a potential representing the maximum intensity encountered. During the return movement the cell output is compared with the capacitor voltage and when equality is achieved a thyratron is fired to energize the magnetic brake on the associated shaft. Each operation transfers the circuit connection to the next brake so that the three movements and adjustments are effected automatically in succession.