Optics: image projectors – Lamp control
Patent
1977-01-18
1978-08-08
Stephan, Steven L.
Optics: image projectors
Lamp control
310 75B, 353110, G03B 2120, G03B 2310, H02K 710
Patent
active
041053141
ABSTRACT:
A hand crank generator-powered slide projector is provided in which the hand cranking both powers a projection lamp to illuminate a transparency and causes automatic film frame advance of the transparencies after a preset number of cranks to provide a stationery illuminated slide display. The generator comprises a stator coil capable of having a current induced therein and a magnetic rotor rotatable within the stator for producing a changing magnetic field across the stator coil due to such rotation for inducing the current therein. The stator coil is electrically connected to the illumination source for providing induced current thereto for enabling illumination of a positioned transparency. The crank is mechanically connected to the rotor for enabling rotation thereof and gear means are drivingly connected to the rotor for enabling simultaneous rotation therewith in response to rotation of the rotor by the crank. The gear means has a finger means mounted thereon for simultaneous rotation therewith with the finger means being mounted on the gear in mechanical alignment with a rotary slide film advance means which comprises a pocket for movably receiving a transparency carrying disc therein having perforations for cooperation with the frame advance mechanism. The finger means engages the frame advance mechanism as the gear is rotated and subsequently disengages from the frame advance means at a predetermined point in the rotation of the gear whereby the frame advance is resiliently returned to the initial position until subsequent advance of the next frame upon reengagement by the finger means. A limiting abutment may be mounted in the frame advance mechanism for selecting between single and double frame advance during each successive cycle of rotation of the gear. A predetermined gear ratio with respect to the rotatable rotor is provided for enabling a predetermined number of rotations of the rotor before the finger means engages the frame advance mechanism to change the positioned transparency so as to enable the positioned transparency to be illuminated for a predetermined interval for projecting the image before the image is changed.
REFERENCES:
patent: 422716 (1890-03-01), Calahan
patent: 1254746 (1918-01-01), Troxell
patent: 1412972 (1922-04-01), Schwarzmann
patent: 2390877 (1945-12-01), Fisher
patent: 2445651 (1948-07-01), Weavie
patent: 2916964 (1959-12-01), Pawlsohn
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