Patent GB-1019297-A (GB)
Title: Improvements in or relating to strip feed apparatus e.g. motion-picture projectors
IPC: G03B21/43
Filed: 1963-08-19
Abstract: 1,019,297. Cine projection apparatus. EASTMAN KODAK CO. Aug. 19, 1963 [Aug. 20, 1962], No. 32688/63. Heading G2E. A cine projector has drive means for selectively feeding film through a projection gate 36 in either a forward projection direction in which a take-up reel drive is operated to wind film on to this reel 30, or a reverse, re-wind direction in which a supply spool drive is operated to re-wind film on to the supply reel 28. Sensing means 34 are provided to sense the increase in film tension when the film end is pulled against an anchorage to the supply reel, the sensing means their operating on the drive means to cause automatic selection of reverse drive, by unlatching a spring-loaded re-wind control. The power drive is not reversed for re-winding and the film is rapidly returned to supply reel 28 until the leader passes film presence sensing device 72 which then returns the re-wind control mechanism to the latched position and the projection control handle 74 to the OFF position. In operation, a supply reel 28 is mounted on spindle 24 and the leader of filmstrip 32 is inserted in guideway 42 of tension sensing device 34 and thence threaded into the entrance of gate 36. Handle 74 is then depressed to start the projector whereby control bar 82 is displaced downwardly by its engagement with protruberances 78, 78<SP>1</SP>, and carries with it reset slide 98. Gear sector 146 is thus rotated about pin 208 by rack 206 to increase the tension in spring 138. Slide 98 is latched in the down position by ear 86 . engaging detent 212. Pin 90 on control bar 82 engages motor control switch 92, which closes contacts for an electrical circuit supplying power to the motor and projection lamp. Flexible belt 110 transmits the rotational power from drive shaft 100 and pulley 102 to pulleys 104, 106, which rotate gears 116,124 and hence rotate spindles 24, 26 through one-way clutches 112,122. In the FORWARD direction clutch 112 does not operate spindle 24, and the film is unwound from reel 24 by the pull-down mechanism 70 and by take-up spindle 26 whose clutch 112 transmits drive in this direction. REVERSE projection is obtained by reversing the drive to shaft 100 when clutch 112 then transmits drive to spindle 24 while clutch 122 is inoperative. The increase in tension when the end of film 32 is reached on reel 28 depresses spring tensioned snubber 44 to rotate bell crank 50 clockwise on its shaft 52 whereby latch lever 136 mounted on the same shaft is rotated to release gear carrier plate 108 for counterclockwise rotation about pin 130 by spring 138. Ear 238 then swings to the right so that it no longer blocks upward motion of cross-bar 220 on shut-off lever 200, but the arm 232 of film sensing device 72 is still in position to block such motion. The rotation of plate 108 tightens belt 118 between hub 114 of drive clutch 112 and pulley 120 of idler pulley 104 while gear 126 is disengaged from gear 124. Thus continued forward drive of shaft 100 results in reverse rotation of supply spindle 24 and the film is re-wound at high speed owing to the ratio of pulleys 114, 120. The rotation of plate 108 also downwardly displaces lug 168 of the bellcrank 162 which rotates clockwise about shaft 100 and engages lug 174 of the gate bracket 176. The bracket 176 is thus displaced laterally and its fingers 182 pull pressure pad 62 away from aperture plate 64. The film is thereby disengaged from pull-down claw 70 and is guided by the protruding ends of plate 64. When the end of film 32 passes film sensing device 72, shut-off lever 200 urged by spring 226 depresses arm 232 against the lighter spring 234 and arms 230, 232 take the dotted position of Fig. 4. Lever 200 continues to move counterclockwise until the end of its cross-arm 220 engages ratchet wheel 128 on idler pulley 106, which is rotating clockwise, and is displaced laterally, ear 222 of lever 200 sliding in slot 224 to permit this motion. Ear 240 of lever 200 then engages edge 242 of reset slide 98 and moves it laterally until detent 212 of slide 98 no longer engages ear 86 and the slide is released, whereupon spring-urged gear sector 146 will vertically displace reset slide 98 upwardly so that lug 216 will engage rubber-covered lug 218 of plate 108 which is thus rotated clockwise about pin 130 until lug 154 again latches to detent 150 of latch lever 136. Simultaneously, shoulder 248 on slide 98 carries ear 240 of lever 200 upwardly to rotate lever 200 clockwise about ear 222 and back to the Fig. 3 position. Cross arm 220 is therefore swung downwardly and out of engagement with ratchet wheel 128 while the rotation of plate 108 again couples pinion gear 121 of pulley 104 to gear 116, and pinion 126 of idler pulley 106 to gear 124. Bell crank 162 is simultaneously rotated clockwise about its axis to displace gate bracket 126 latbrally to reset pressure pad 62 relative to aperture plate 64. In moving upwards, reset slide 98 moves control bar 82 and starting handle 74 to the OFF position. The apparatus is then ready for a further cyle of operations.