Patent GB-401814-A (GB)
Title: Improvements in automatically controlled cinematograph projectors
IPC: G03B21/42
Filed: 1932-07-15
Abstract: 401,814. Kinematograph projectors. COMMUNITY SERVICE, Ltd., 1, Montague Street, London.-(Foster, W. D. ; 4, Wilsey Square, Ridgewood, New Jersey, U.S.A.) July 15, 1932, No. 20057. [Class 97 (i).] A projector having means whereby the film, or part of it, is automatically rewound and reprojected after each projection, is so constructed that the film, when starting to move in the projecting direction, is moved by the take-up spool only, and without constraint by the usual intermittent-feeding member, driving connection thereto, and to the shutter, being effected subsequently ; during rewinding the intermittent feeding member may be covered by a stripper plate, the gate may be open, and a cut-off shutter may be operative, the stripper plate being removed and the gate being closed simultaneously with restoration of the driving connection to the intermittent feeding member, and the cut-off shutter being opened subsequently ; means for varying the length of the portion of the film projected and rewound, means for manually causing the direction of feed to be reversed when desired, and means for taking up film slack and braking the film spools, may also be provided. In the construction shown, the projector is driven by means of a motor through a pulley 58 on a shaft 54 carrying a worm 72 and a spur wheel 53 meshing with a spur wheel 52 which is loose on a shaft 49 and is secured to one disc 61 of a friction clutch ; the other disc 60 of the clutch is rotatable with, but slidable on, the shaft 49. and the drive of the shaft 49 is thus controlled by the clutch. The shutter and an intermittent sprocket are driven from a shaft 44 having a spur wheel 47 meshing with a spur wheel 48 on the shaft 49. The take-up and pay-out spools are alternatively driven from a cross shaft 19 carrying and continuously driven by, a worm wheel 73 in mesh with the worm 72, the shaft 19 being provided with a bevel gear 22 meshing with a bevel gear 74 at the bottom end of a shaft 75 connected, at its upper end, by bevel gears 76, 77 to a shaft 35 ; the gear ratios are such that the shaft 35 rotates faster than the shaft 19. The shafts 19, 35 are coaxial respectively with the spindles 6, 8 of the take-up and pay-out spools, and a friction clutch and a pin clutch are described by which they may be respectively connected to them. The film F in its passage to the gate passes over a yieldable guide 16 carried by a tension lever 14 carrying a spring 40 fitted with a brake shoe 39 capable of engaging a drum 38 on the spindle of the payout spool; it also passes under the loop 15 of a spring 13 exerting downward pressure on the film. In its passage from the intermittent sprocket 10 to the take-up spool, the film passes over a guide 12 carried by a lever 11 and urged upwardly to form the film loop. Braking means for the take-up spool carried by the lever 11, is described. A cam 109, carried by the shaft 75, and thus rotated constantly during projecting and rewinding, may be engaged by cam-follower projections on any of four arms 100, 101, 103, 104, rockably carried on shafts 31, 102 ; engagement of any of the projections with the cam 109 causes rotation of one of the two shafts 35, 102 in one direction or the other, and effects one or more operations in connection with the reversal of the direction of feed. Linkages are described by which the follower arms are rocked from a shaft 78, the shaft 78 being driven from the spindle 8 of the take-up reel by means of gears 96, 95, worm 93, worm wheel 92, worm 88, and worm wheel 87. The shaft 78 is hollow and has a shaft 83 fitting friction-tight within it ; each of these shafts carries a cam disc, 81, 85, fixed thereto and having a nose which engages, in one case, with a pin 112, and, in the other case, with a pin 204, both the pins being carried by a bell crank 97. The engagements of the noses and pins rock the bell crank 97 in one direction or the other and actuate the linkages. The shafts 78, 83 carrying the cam discs 85 are rotarily adjustable to vary the points in the film run at which the automatic changes occur, and a graduated disc 82 and pointer 84, Fig. 2, respectively carried by the two shafts, indicate the settings of the cam discs. A handle 203 is provided by which the bell crank 97 may be rocked by hand to produce changes non-automatically when desired. Fig. 1 shows the mechanism just after the cam disc 85 has rocked the arm 103 into position for its follower to be engaged by the cam 109 to initiate rewinding. The engagement turns the shaft 102, and, in turning, the shaft causes three actions to take place, viz. :-(1), by means of a pin 135, link 136, and other link-work described, it turns a hinged cut-off shutter into operative position, (2) by an arm carried by it and connected to a lever 67, Fig. 5, a link 66 and a lever 64, it opens the clutch in the drive to the sprocket and shutter, and (3) by means of a link 145, Fig. 1, and levers fixed on a rock shaft 140, it depresses a rod 138 to rock the arm 100 into position for its follower to engage the cam 109. After the time occupied by the further rotation of the shaft 75 through approximately three-quarters of a turn, the cam 109 comes into engagement with the follower on arm 100 and rotates the shaft 31. The shaft 31 in rotating effects five actions, viz. :-(1) through a plate 160, Fig. 1, and links 161, 162 it rocks a shaft 28, Fig. 5, carrying a fork 37, to engage the clutch in the drive to the pay-out spool, (2) through the plate 160 and links 163, 164, it rocks a tubular shaft 27, surrounding the shaft 28 and carrying a fork 25, to disengage the clutch in the drive to the take-up spool, (3) through link-work described, it rotates a shaft 168, Fig. 2, to move a rod 165 longitudinally and carry a gate member parallel to itself and away from the film, (4) through the rod 165 and an arm 192, carrying a toothed sector engaging a gear on the shaft of an arcuate stripper plate 188, it rotates the plate to separate the film from the intermittent sprocket, and (5) through link-work described, it raises a plate 150, Fig. 1, so that a finger 202 formed on it overhangs the follower arm 104. During the rewinding, the shafts 78, 83 are rotated from the reel which is normally the take-up reel, until the other cam disc thereon engages the pin 204 to rock the bell crank 97 into its other position. The rocking of the crank 97 causes a lever 152 pivoted at 153 to lift the arm 101 into position for its follower to engage the cam 109. The engagement rocks the shaft 31 back to its original position, thus producing reversal of the driving connections to the spools, and starting the movement of the film in the projecting direction ; the arm 104 is also raised into position for its follower to engage the cam 109. After a further three-quarters of a turn of the shaft 75, the shaft 102 is rotated through the cam 109 and follower arm 104 ; the stripper plate 188 is then withdrawn from between the sprocket and film, and the drive for the sprocket and the shutter is restored. The stripper plate may be replaced by means enabling the sprocket to be freed from its spindle. Arrangements of toggle levers and springs, provided to assist the movements of various shafts into their extreme positions, are described.