GB1265902A - - Google Patents

Abstract

1,265,902. Mechanical switches; electric motor controllers. G.A.F. CORP. 18 June, 1969 [24 June, 1968], No. 30775/69. Heading H1N. [Also in Divisions G2-G3] A slide projector 14 has a random selection system comprising detachable slide indexing unit 12 remotely controlled by unit 10 to bring any one of the slides in rotary tray 198 to the projection position, the tray being rotated in a direction giving the least rotational displacement. The system may also be used with linear slide trays. Rotation of selector knob 18 on unit 10 locates a selected slide number on scale 30 beneath mask 26, the scale being carried on a disc 28, Fig. 6, which is thereby rotated on shaft 56, Fig. 7. The underside of disc 28 carries arcuate contacts 49, 50 of opposite polarity with insulating spacers 51, 52. Detent teeth 46, 47 are selectively engaged by springs 140, (141) or 150, 151 for forward or reverse indexing. "Initiate" button 22 closing contacts 42, 44, Fig. 20, is then pressed to energize a motor 162 driving a commutator device on shaft 173 in unit 12 which provides pulses to a D.C. stepping motor 97 in the remote unit 10. Motor 97 then incrementally rotates gears 62 or 74 coaxial on shaft 56 in a direction determined by which of the contacts 49, 50 is wiped by a seeking contact 71 fixed on gear 62 or a contact 82 fixed on gear 74. Rotation continues until contact 71 reaches a spacer 51 or 52, when the circuit of motor 162 is broken. Motor 162 also drives indexing gear 196 engaging rack teeth 197 on slide tray 198 which is thereby rotated until contact 71 reaches the selected slide position. A selector switch 24 is set for a "100 slide" or "80 slide" tray and engages the drive from motor 97 to gears 62 or 74 through pinions 95 or 94, the gears having corresponding numbers of teeth. Movement of switch 24 also moves a mask to expose the "80 slide" or "100 slide" scales 30 in window 25, and sets a switch 101 to connect either of contacts 71 or 82. Single step forward or reverse indexing is possible using buttons 21 or 22 which also close contacts 146, 155, Fig. 20. When "initiate" button 20 is pressed, solenoid 214, Fig. 16, is energized to release pawls 201, through arm 209, from locking engagement with indexing gear 196. A further solenoid is energized to close "load" switch 264 to operate a half cycle of the slide changing operation in which a slide is removed from the gate. Tray 198 is then rotated until the selected slide is at the projection position when the solenoid is de-energized together with motor 162; the changing cycle is then completed to move the new slide into the gate.