An improved device for moving a flat object in its own plane to position it, especially in an optical projector

摘要

749,503. Optical - projection apparatus. NORTHERN ENGRAVING & MANUFACTURING CO. July 24, 1952 [May 3, 1952No. 18763/52. Class 97 (1). Positioning apparatus for moving a flat object in perpendicular directions in its own plane comprises a carriage to support the object movable in one direction and means on the carriage engaging both faces of the object and adapted to move the object in a perpendicular direction, the said means being released from engagement with the object, to allow it to be removed, when the carriage reaches the limit of its movement. In the optical projection apparatus shown in Fig. 1 a microphotograph C is held by a pressure member 32 against a transparent panel 22 and is illuminated, for episcopic projection by a lens in a mount 24, by a lamp 12 with reflector 14 and condenser elements 16, 18, 20. The microphotograph is movable in two perpendicular directions, to select part for projection by mechanism in a casing 34. Fig. 2 is an underside view of the mechanism, with the bottom of the casing removed, and Fig. 8 is a transverse section. The microphotograph is held between spring- loaded pressure rollers 122, 124 and rubbercovered rollers 116, 118 on shafts 72, 74 rotatable through gearing 80, 82, 84, 86 by a knob 94. The rollers are slidable on the shafts 72, 74 and the whole roller assembly is slidable by rotating, by a knob 71, a leadscrew 60 with which the roller assembly has driving connection through a spring-loaded ball 182 (Fig. 8) in a bore in a block 102 to which the remainder of the roller assembly is secured. The rollers 122, 124 are carried on plates 126, 128 carried on pivots 130, 132 round which are springs which urge the plates in the direction to engage the rollers 122, 124 with the rollers 116, 118. Abutments 196, 198 on the pivoted plates engage projections 192, 194 on a bridge member 186 pivoted at 188 to the block 102 to urge one end downwards to engage the ball 182 and provide the necessary pressure thereon. At the end of the travel of the roller assembly if rotation of the leadscrew is continued, the ball is driven out of the leadscrew to pivot the member 186 and lift the rollers 122 and 124. The pivoting of the member 186 causes a downward movement of the portion 210 and at the end of the movement of the roller assembly to the right, as shown in Figs. 1 and 2, this portion engages under the hooked end 208 of the spring blade 206 on which the pressure member 32 is carried. The microphotograph is thus freed for removal and replacement.