Patent GB-1390783-A (GB)
Title: Motion picture projector
IPC: G03B21/43
Filed: 1972-03-16
Abstract: 1390783 Cinematography EASTMAN KODAK CO 16 March 1972 [22 March 1971] 12277/72 Heading G2E A cine projector having at least forward projection, threading and reverse winding modes includes a gate 12 with feed claw 21, a drive sprocket 124 and a film path which ensures contact between the film f and sprocket in the forward projection mode (soundtracked films only) and at other times to by-pass the sprocket. A movable film guide is provided to direct the film f relative to the sprocket 124. As shown in Fig. 4A the film f passes over snubber 22, through gate 12, past loop former 40, sound reproducing head 48 between capstan 54 and roller 106, around sprocket 124 and then to a take up spool (not shown), in the forward projection mode. The position of these components in various modes are controlled by the movement of levers 46, 60. The lever 60 is urged anticlockwise by spring 64 about pin 62 and the lever 46 has a pin 87 engaging slot 88 on the lever 60. A pin 43 on loop former 40 is abutted by the end 45 of lever 46, pressure plate 82 has springs 84, 86 on a stud 80 passing through bracket 78 on the lever 60 and roller 106 is movable towards capstan 54 by bracket 108 against the action of spring 104. Further a film guide shoe 112 pivots about pin 114 and is held by leaf spring 118 close to the sprocket 124 against the action of spring 116. Also the lever 60 has a rack 74 which engages pinion 134 formed on film guide member 128. Movement of the lever 60 rotates the pinion 134 to rotate the filmguide member 128 which moves the film towards/away from the sprocket 124. The movement of the lever 60 is caused by follower 70 resting against cam surface 140. The cam member 136 is mounted on the same shaft 126 as the sprocket 124 and pinion 134 (looselymounted). A clutch mechanism 142 is also coaxially mounted and includes two members 150, 152 urged anti-clockwise by spring 156 about a pin 146 to engage teeth 160. As shown in Figs. 4A, 4B the projector is in the forward projection mode with the film engaging the sprocket 124. Film Threading Mode Film spool is fitted in the projector and button 216 closed by operator, this energizes solenoid 184 and draws plate 178 to the right so that end 176 of lever 166 is withdrawn from contacting member 150 and end 174 of lever 164 is placed in the path of the member 150. This permits the members 150, 152 to pivot about pin 146 causing end 158 of member 152 to engage teeth 160 and rotate the cam 136 thereby moving lever 60 from the position shown in Fig. 4A (film threading path closed) so as to assume the position shown in Fig. 5A (threading path open). The threading path is relatively open and the film f passes out to the take-up spool (not shown). During film threading the movement of the film guide member 128 closes switch 210, thereby keeping solenoid 184 energized. However the take-up reel drive mechanism, when the film has been attached thereto, will increase the film tension so that the film f bears against roller 132 and rocks the guide member 128 sufficiently to open switch 210. This de-energizes the solenoid 184 and returns it, the cam 136 and clutch mechanism 172 to the Fig. 4B position. This closes the threading path, the film guide member 128 pivoting so that the film f slowly contacts the sprocket 124. Still, Reverse and Manual Rewind Modes In addition to other movements of the projector to accomplish these modes of operation in each case button 214 is closed so as to open the film path between the gate 12 and the take-up reel. The projector then functions sprocketlessly. Automatic Rewind Increasing film tension at the end of the reel causes snubber 22 Fig. 4A to close switch 28 and open film path. Silent Projection As shown the film passes over head 48 and around sprocket 124 in all forward projection modes, however a further switch to energize the solenoid 184 may be provided which opens the film path so that the projector acts sprocketlessly in a forward direction.