Patent GB-728490-A (GB)
Title: Improvements in or relating to sheet-feeding mechanism for photo-composing machines
Inventor: WILLIAMS JOSEPH HENRY
IPC: B41B21/32
Filed: 1953-09-24
Abstract: 728,490. Photographic type-composing; change boxes. MONOTYPE CORPORATION, Ltd. Sept. 24, 1953, No. 26298/53. Class 98 (1). A light-sensitive sheet feeding mechanism for a photo-composing machine comprises a rigid cylindrical support having sheet-registering devices and rotatably mounted within a light-excluding casing, a longitudinally adjustable measuring bar bearing a rack, a reduction gear between the rack and toothed gear rings on the sheet support, handoperated mechanism for initially setting the measuring bar on a fixed scale, mechanism for periodically moving the rack into engagement with the driving gear, and mechanism operated periodically to move the measuring bar and rack to rotate the sheet support through the reduction gear. As shown, a light-tight magazine B provided with locating pins engaging sockets on the machine houses a drum A on which a light-sensitive sheet is held by adhesive tape when located by a cross strip and a side flange and which has a pair of marginal gear rings secured to its hub and meshing with pinions secured on a common shaft A<SP>5</SP> which also bears a gear C. This gear is rotated by a rack C<SP>1</SP> engaging a vertical spline on a slide C<SP>5</SP> having a roller C<SP>19</SP> engaging an eccentric cam disc F on a shaft D<SP>1</SP> driven by a bevel gear from a bevel gear D<SP>3</SP> on a driven shaft of the machine. The extent of rotation of the gear C is determined by the length of stroke for which the rack C<SP>1</SP> is engaged, this being varied by means of a threaded rod C<SP>15</SP> rotatable by a knob C<SP>17</SP> and engaging in a nut C<SP>15</SP> fixed to the slide, the extent of the stroke being indicated on a fixed scale C<SP>10</SP> by an index C<SP>8</SP> on the slide. The rack is movable perpendicularly to the slide to bring it periodically into engagement with the gear C so as to rotate the drum clockwise only by a T- piece C<SP>2</SP> having its stem slidable in a guide C<SP>3</SP> and slotted at C<SP>4</SP> to receive the end of a lever C<SP>7</SP> pivotally mounted at c having a roller C<SP>20</SP> engaging in a concentric cam groove in the face of a disc D on the shaft D<SP>1</SP>, the gear being held meanwhile by a pawl carried on an arm E<SP>1</SP> pivoted to a lever E<SP>2</SP> at E<SP>4</SP> and clamped by a releasable screw E<SP>3</SP> having a pin entering a slot in the lever. From the position shown, continued anticlockwise rotation of the cam disc D causes a roller E<SP>5</SP> on the lever E<SP>2</SP> to fall into the cam groove and release the gear from the pawl. The rotation of the drum from its initial position is shown by a coarse scale G on the drum shaft and a fine scale G<SP>2</SP> on the gear. The magazine is loaded in a dark-room and the drum is rotated so that the exposure gate B<SP>4</SP> is closed by a pad A<SP>7</SP>. The pawl is then disengaged by slackening the screw E<SP>3</SP> and when the magazine is located on the machine the drum is rotated to bring the scales to zero, thus opening the exposure aperture and presenting the top of the light-sensitive sheet to it.