GB922711A - Improvements in or relating to optical slide projectors - Google Patents

Abstract

922,711. Optical slide projectors. C. BRAUN, and W. BRAUN, [trading as CARL BRAUN CAMERAWERK. Jan. 26, 1959 [Aug. 7, 1958; Sept. 5, 1958], No. 2800/59. Addition to 912,366. Class 97 (1). The optical slide projector of the parent Specification in which a slide plunger is movable transversely to a slide magazine for effecting transfer of slides into the axis of projection and their return to the magazine and the slide plunger is manually operable and also can be connected by a coupling device to a drive member driven by an electric motor for powered transfer and return of the slides, is modified by the provision of a projector cooling fan driven by said motor and of means for drivecoupling the drive member for the slide plunger to the cooling fan motor shaft. As shown, a slide is located in the projection gate. When motor 74 is energized so that the fan 76 is operating and a generator coil in the motor is providing a voltage across lines 213, 231, operation of press button 209<SP>1</SP> energizes relay 106 to pull lever 88 anticlockwise against action of spring 86 and also to pivot lever 81 anticlockwise against a spring 115, thus moving the rim of a friction wheel 78 on the lever against the friction sleeve 77 on the motor shaft. The movement of lever 88 moves arm 89 past a leaf spring 112 which holds it against return. Rotation of the wheel 78 through gears 92, 93, 94, 96 rotates the drive gear-wheel 32 as shown. A crank 30 pivoted on the drive gear-wheel is connected by a link 73 to a reciprocable transport member 22 movable along guides 27 (Fig. la) and returns the slide to the magazine. After 180 degrees rotation of the wheel 32 the flange 57 of an eccentrically mounted cam 56 engages a toothed wheel 58 on a shaft 14 to rotate it one tooth thereby moving the magazine to present the next slide, which on continued rotation of the wheel 32 is fed into the projection gate. On return of the crank 30 into engagement with the lever arm 109, spring 112 releases the arm 89 so that levers 88, 81 return to the position shown until relay 106 is again operated. If the motor 74 fails the slide plunger can still be operated manually by raising a normally disengaged gear-wheel 98 into the position shown to engage gear 94, the gear-wheel 98 having a manually accessible casing 99. The operating button 209<SP>1</SP> and switch 209 for the relay are provided in a switch housing 210 which also contains a press button 208<SP>1</SP> and switch 208 for a motor 207 which through worm 218 and gears 343, 340 causes focusing movement of the projection lens 2. An alternative form of switching is also described in which a single 3-position pole can be caused to energize relay 106, motor 207 or neither. Specification 922,712 is referred to.