Patent GB-1301870-A (GB)
IPC: G03B21/32
Filed: 1970-10-22
Abstract: 1301870 CinÚ projectors; film cartridges ELMO CO Ltd 22 Oct 1970 [22 Oct 1969] 50345/70 Heading G2E A film cartridge 1 is formed of two detachable units 2, 3 which, when not in use, are held together by resilient means 4, 5. The unit 2 contains a film wound on a rotatable reel 15 with one end  secured thereto, while the other end is attached to a core 16 contained in the unit 3. The film is threaded through the film track of a projector Figs.7-9 (not shown) by mounting the cartridge on a spindle (17) which engages the reel 15 and moving a lens (24), holder (19) and pressure plate (20) away from aperture plate (21) so that the whole unit 3 may be moved through the film gate after being detached from the unit 2. Eventually a friction roller (22) on take-up spindle (18) is driven by the driving system of the projector. The film gate is then closed. The unit 3 may be dispensed with Figs.10a, 10b, (not shown), and the core (16') only moved through the film gate. Two other forms of two unit cartridges are described Figs.11a, 12b (not shown). The projector is provided with a stationary support plate 27 (Fig.14) and a movable support plate 29. A cartridge is inserted when the two plates are in contact, such insertion causing the cartridge to be held by grips 37, 38 and also pivoting assemblies 41, 42 to move hinged plates 60, 61 to the left, as seen. To separate the cartridge units, a rod 28 is rotated, thereby initially allowing arm 34 to move downwards (as seen) alone. This causes grips 45, 47, 50 and 51 to turn inwards and grip the sides of the cartridge. Further rotation of the rod 28 also moves the plate 29, and hence the grip 38, downwards. Movement of the grip 38 allows a plate 59 to descend, and consequently both the plates 60, 61 return to positions of alignment with the plate 59. The projection of the film can be effected. The plate 29 is raised, when the rod 28 is rotated in the opposite direction, by the arm 34, which is able to move upwards after the support plates 27, 29 abut so as to release grips 45, 47, 50 and 51. The upward movement of the plate 29 causes the grip 38 to be tilted down as a part 42 thereof is pushed by the plate 61. Similarly the plate 60 lifts the grip 37 thus the cartridge is ready for removal when the plates 27, 29 abut. The driving mechanism (Fig.17). Insertion of a cartridge 1 depresses a switch 94 to connect a power source thereby starting motor (71) Fig.18, (not shown), to rotate the supply spindle 17 and switching on a lamp (97). Simultaneously, an electromagnet 88 is operated to start rotating the rod 28. When the unit 3 reaches its lowest position (shown in chain-dot lines), in which the friction roller 23 is connected to the driving roller, a switch 93 is held open thereby de-energizing the electromagnet 88 and stopping a motor (84) started by depressing the switch 94, which motor has  returned the lens to its projection position. Upon completion of projection, the tension in the film increases, since the trailing end is fixed to the supply reel 15, so a lever 80 is operated by a tension roller 80' to close switches 77 and 96, thereby reversing the motors (71, 84) to rewind the film and open the film gate, as well as switching off the lamp (97). Simultaneously the rod 28 is rotated to raise the support plate 29. The switch 94 is opened when the cartridge is pushed away from the plates 27, 29.