GB1282595A - Projection reader - Google Patents

Abstract

1282595 Projection reader pacer CONSOLIDATED EDUCATIONAL PUBLISHING Inc 22 July 1969 36681/69 Heading G5G [Also in Division G2]. A projection reading pacer for use with film having lines of reading material comprises a film guide arranged to permit projection of at least one line of reading material, a film advance mechanism connected to a main drive and a reciprocating scanning mask operatively connected to the main drive and moving in scanning and return directions with respect to the lines of reading material, the return movement being independent of the main drive. As shown the film advance mechanism includes sprockets 60 operated intermittently through a pawl 46 (Fig. 3) by a continuously rotating drive shaft 20, 36, the pawl being mounted on the shaft so as to allow pivotal and limited longitudinal movement, being moved in one direction by a snail cam 42 and in the return film advancing direction by a spring 54. A projection gate 26 has a mask opening 102 which, by means of a mask adjusting lever 104, can be made to register with a line of reading material disposed transversely on the film (not shown). A scanning mask 24 with an opening 30 is made to reciprocate along the direction of the opening 102, the slow scanning movements being produced by a cam driven by the shaft 20 and the quick return movements by a helical spring 39. A felt bumper 37 or dashpot 237 (Fig. 7, not shown) stops the mask at the end of its return movement. The mask 28 may be moved down to a position in which the scanning mask 24 is blanked out and an alternative opening 108 registers with the projection gate 26 to permit projection without scanning. The shutter may be made of opaque material or coloured transparent or translucent material. The pawl 46 may be pivoted to a position where film may be advanced manually. In modifications, the mask 28 may be provided with only a single opening (Fig. 4, not shown), the opening may be slanted as at 304 (Fig. 12), film may be advanced continuously by a reduction gearing from the drive shaft 20 (Fig. 8, not shown) rollers instead of sprockets may be provided (Fig. 14, not shown) the shutter may be pivoted to a position where it is ineffective (Fig. 8, not shown) and a sliding plate may be provided on the scanning mask for blacking out the screen during return movements.