GB1060413A - Improvements in or relating to projectors for slide transparencies - Google Patents

Abstract

1,060,413. Slide projectors. T. GANZ and A. GANZ-KEYSER. April 16, 1964 [April 16, 1963], No. 15862/64. Heading G2J. A motor-driven slide projector has two magazines 10 on opposite sides of the optical axis, and a slider 15 accommodating two transparencies 2 which is movable between the two magazines whereby transparencies are moved in turn from each magazine for projection and back again. A shutter operates during the change. The magazines have partitions 12 forming slide compartments open at the top and inner side, and are Indexed on rails 11 relative to slider 15 by means of studs 32 entering sleeves 31 which are driven longitudinally by their spring-loaded engagement with screw-threaded shafts 30. These shafts are driven in one-revolution increments by reversible motors 36 whose control switches 38 are operated by cams 37 on each shaft 30. At the end of their motion on shafts 30, sleeves 31 operate switches 39 to stop motors 36. A pivoted sensing arm engages the inner edges of slides 2 and when no more remain in the magazine its resulting movement operates a reversing switch for motor 36. Slider 15 has a rod 20 sliding in brackets 19 and is driven through a rack and pinion 17 by a reversible motor, the two slides being held between arms 16. The slide in the projection position is pressed by spring-loaded pin 23 against centering blocks 27, the pin being operated by electromagnet 25 and arm 24. At each end of its motion, the slider operates a switch to index the magazine receiving one arm of the slider and so introduce a new slide which is transferred to the optical axis on the next movement of slider 15. Further operation of the master switch then starts this return movement.