Patent GB-1325097-A (GB)
Title: Film transport devices
IPC: G03B27/58
Filed: 1971-06-17
Abstract: 1325097 Film transport in microfilm cameras PENTACON DRESDEN KAMERA-UND KINOWERKE VEB 17 June 1971 28513/71 Heading G2A A microfilm camera for taking a series of pictures arranged in horizontal lines and vertical columns has a picture window 52 across which a light-sensitive film sheet is carried by a line carriage 2 moving vertically, the carriage 2 itself being mounted in a column carriage 1 which moves horizontally. A plate 35 is fixed to carriage 1. Carriage 2 can be driven downwards, and carriage 1 to the right, by a driving weight 38 at one end of a cable 37, which is guided round a pulley 36 on plate 35 and has its other end attached to carriage 2 by a clamp 46. Secured to carriage 2 is a stepping rod 30, and a similar stepping rod 31 is secured to carriage 1. These rods have respective sets of ratchet teeth 32 and 33, and the step-by-step movement of the rods is controlled by an escapement-type mechanism of the type described in more detail in Specification 1322417: teeth 32 are engaged by pawls 41 and 42 actuated by a lever 40 controlled by an electromagnet 39, and teeth 33 are engaged by pawls 49 and 50 actuated by a lever 48 controlled by an electromagnet 47. The carriages are initially set in the cocked position by drawing column carriage 1 into its extreme left position Fig.3 (not shown), and line carriage 2 into its highest position, Fig.1, each of these movements being against the action of the weight 38. This cocking movement is effected by a winding motor 3 which drives a worm spindle 4. Motor 3 is mounted on a plate 23 which is slidably pivoted on a pin 11, so that the plate can be given a slight angular movement one way or the other by a plunger 58 operated by an electromagnet 10. This brings the spindle 4 into engagement with either wheel 8 on one side (winding position I) Fig.2 (not shown), or wheel 5 on the other side (winding position II), Fig.3 (not shown). Wheel 8 carries a cable drum 67 on which is wound a cable 9 attached to carriage 1 by means of a clamp 68. Thus in winding position I, carriage 1 is drawn to the left until it abuts against a stop 20. In winding position II wheel 5 is connected through gear 62 to a toothed segment 63 on a lever 6. Lever 6 is thus pivoted anti-clockwise against a spring 64, so that a pin 66 at one end engages under an arm 7 of rod 30, and lifts it, and hence carriage 2, upwards. After both carriages 1 and 2 have been cocked, the series of exposures is initiated by pressing release button 82, which closes a switch 79 and hence causes shutter blade 53 to make a single revolution the exposure being effected during the brief uncovering of window 52. A lug 55 on shutter 53 then closes a switch 56, which energizes the magnet 47 and so causes the pawls 49 and 50 to move the rod 31, and hence carriage 1, along the distance between one tooth 33 and the next. When carriage 1 has reached the right-hand end of its horizontal traverse, after thirteen step-and-repeat movements corresponding to the thirteen ratchet teeth 33, the stepping rod 30 has reached the position shown in broken lines, where it closes a switch 75. This energizes the magnet 39 which causes the lever 40 to pivot and close switch 70. Thus magnet 10 is energized, and the motor 3 and spindle 4 are pivoted into position I, so that carriage 1 is drawn to the left again. Continued pressing of release button 82 now causes the line carriage to be traversed downwards step by step under the action of the pawls 41, 42. In the modification of Figs.5 and 6 (not shown), the spindle 4 is in engagement with both wheels 5 and 8, driving connection with one or the other being made through a clutch arrangement.