Patent GB-568600-A (GB)
Title: Improvements in cinematograph projectors or like apparatus
IPC: G03B15/08
Filed: 1943-04-15
Abstract: 568,600. Kinematograph apparatus. CLARK, D. E. April 15, 1943, No. 6026. [Class 97 (i)] In a projector having two film tracks and co-operating parts which are simultaneously and oppositely movable between the projecting position and a re-loading position to one side of it, the film-feed being automatically transferred to the track moving into projection position, the arrangement is such that the tracks change places during transfer and are given relative movement to allow them to pass one another. In the projector shown two supply and two take-up spools (not shown) are mounted to the right and left of the optical axis on arms 7, 8 respectively. One film A passes from its supply spool round a feed sprocket 12a, through a gate 11a, over an intermittentlydriven sprocket 13a, a sound drum 14a and takeup sprocket 15a to the take-up spool. The other film B passes round a sprocket 12b through a gate 11b, over an intermittently-driven sprocket 13b, sound-drum 14b and take-up sprocket 15b to the second take-up spool. The gate 11a is carried by an arm 9 pivoted on a horizontal rod 21, and the sprocket 13a, arm 10a carrying the sound-drum 14a, and the sprocket 15a are respectively carried by a driving-spindle 18a, rod 24, and spindle 19a, all of which, together with the rod 21, are mounted at one end on a plate 36a by which they may be simultaneously slid to move the parts carried by them between the projection and re-loading positions. On a second plate 36b are mounted rods 20 carrying the gate 11b, the spindle 18b of the sprocket 13b, and a spindle 19b for the take-up sprocket 15b. On the spindle 19b is also pivotally mounted an arm 10b carrying the sound-drum 14b. The plates 36a, 36b are connected respectively by links 37a, 37b to the ends of a double lever 38 which is swung by arcuate movement of a hand lever 41 to produce movement of the plates towards or from each other, so causing the two sets of film track members carried by them to move oppositely between the projection and reloading positions. In moving film A from the loading to the projection position the lever 41 is pushed inwards against a spring, causing an arm 48, Fig. 4, to engage an arm 46 which rocks the arm 10b and so swings the sound-drum 14b to the position shown in Fig. 1, in which it can pass the drum 14a of the other track. When the lever 41 is released after the cross-over movement of the tracks an arm 47 engages an arm 45 on the shaft 21 which rocks the arm 9 to carry the gate 11a to the front, to take the position previously occupied by the gate 11b. On again interchanging the tracks the movements are reversed, the gate 11a first being moved to the rear to clear the gate 11b, the tracks then being moved past each other, and finally the sound-drum 14b moving to the rear to the position previously occupied by the drum 14a. The lever 41 also operates a shutter 49 to cut off the projection beam during the change over. The driven members of each film track are operated by gears on the corresponding one of a pair of vertical shafts, which are alternatively clutched to the driving shaft by the movement of the lever 41. Two flicker shutters are provided, one mounted on a tubular shaft around that of the other, each being driven from one of the vertical shafts. Clutches are provided by which the feed spool of the film not in projection position may be reversely driven for re-winding.