Patent GB-651746-A (GB)
Title: Improvements in or relating to photographic projection printers
IPC: G03B27/32
Filed: 1948-02-26
Abstract: 651,746. Photographic projection-printing apparatus. KODAK, Ltd. Feb. 26, 1948, No. 5865. Convention date, Feb. 28, 1947. [Class 98 (i)] In apparatus of the kind comprising a shaft connected to a platen for the light-sensitive printing paper and rotatable by means of an operating member, and actuating means for translating the rotation of the shaft in one direction into an opening movement of a gate for negative film and in the opposite direction into a closing movement of the gate in unison with the respective opening and closing movements of the platen, the actuating means is operable, in order to open the gate independently of the rotation of the shaft and the opening of the platen, by manually operable means connected to the actuating means by a lost-motion connection which renders the manually operable means inoperative during rotation of the shaft. As shown, the imagebearing area is held by a gate supported by a plate 11, illuminated by a lamp 12 and projected on to light-sensitive paper placed over an aperture 16 in a housing 15 and held in contact therewith by a platen, not shown, which is raised or lowered as by a parallel motion linkage on rotation of a shaft 17 journalled in the housing 15. An arm 42 with a handle 44 is pivoted to the side of the housing 15 and linked to a crank 38 on shaft 17 to raise and lower the.platen to change the paper after exposure. A cam 45 loosely mounted on shaft 17 has an arcuate slot 46 through which a screw 47 passes to engage an extension (not shown) of the crank 38 ; by tightening the screw the cam is made fast with shaft 17. The film gate consists of apertured plates 20, 21 hinged at 24. The upper plate 21 has pins 25 sliding into holes 26 in the lower plate 20. Lugs 32 on the top plate carry pins 31 engaged by the bifurcated ends of a yoke 29 fast with a shaft 28 rotatably mounted on the plate 11. The end of the shaft 28 carries a crank 33 pivoted at 34 to a vertically movable bar 35 spring-urged to bear at its upper end on the cam 45. When handle 44 is operated to raise the platen, rotating shaft 17 and cam 45, bar 35 is moved downward, rotating shaft 28 by means of crank 33, and raising the top plate 21. An image-bearing strip can then be moved through the gate, which closes to clamp the strip when the platen is lowered. This arrangement does not lift the pins 25 clear of the front holes 26 ; to remove or insert a strip the gate is opened to clear the pins from the holes. A strip 70, bent at right-angles at its ends, pivots on a shaft 66 supported by brackets on the plate 11, and carries a plate 65 at one end and an angle strip 58 at the other end. The tapered end of bar 35 extends through an aperture 57 in the strip 58 and terminates in a knob 59. Rotation of plate 65 to the right causes the end of strip 58 to bear on the knob and pull down bar 33, opening the gate. Plate 65 returns under spring action when released and the gate closes. When the images are separated, a part of the cam with a greater radius vector is brought into action by slackening screw 47, rotating the cam, and reclamping, so that the gate is opened at each operation sufficient to clear the pins 25 from their holes.