Patent GB-916459-A (GB)
Title: Improvements in or relating to film strip apparatus
IPC: G03B21/32
Filed: 1959-04-23
Abstract: 916,459. Film strip apparatus. KODAK Ltd. April 23, 1959 [April 25, 1958], No. 13960/59. Classes 97 (1) and 98 (1).  A film strip apparatus of the kind in which a light-sensitive film strip or a film strip bearing images is contained in a magazine adapted to be inserted in a cavity in the apparatus, comprises film-feeding mechanism for withdrawing from a magazine located in the magazine receiving cavity, a film strip carrying on its leading end switch-controlling means, locking-means which is normally held in a position for preventing the withdrawal of the magazine from the cavity, electromagnetically-operated actuating means for moving the locking means to an inoperative position, and a switch disposed in the path of movement of, and operated by the switch controlling means, so as to open the circuit of the electromagnetically-operated actuating means, thereby permitting the locking means to return to the operative position, when a predetermined length of the film strip has been withdrawn from the magazine. Figs. 1 and 3 show respectively a plan and side elevation of a magazine interlock mechanism, for use in a microfilm reader, camera, or film-strip projector, such apparatus having a magazine M insertable into a magazinereceiving cavity formed by walls 11, 13, 17 and 18. As the magazine is inserted into the cavity, it closes a micro-switch 41, thereby lighting a signal lamp and energizing a solenoid 45 which attracts a plunger 47. Movement of the plunger is transmitted through an arm 85 to a pivoted locking-bar 83 which moves from the full line to the dotted line position of Fig. 3, thereby allowing the magazine to be inserted further into the cavity. Movement of an arm 77 with the plunger 47 is transmitted through a lever 79 to close a micro-switch 81 and to move a shoe 80 out of engagement with a switch-controlling- stop S. This stop is fixed to the leading end of the film and is arranged to prevent complete return of the film into the magazine. Movement of the plunger is also arranged to move a contact roller 55 out of engagement with the stop S, said roller 55 being carried by a pivoted crank lever 51 connected to the plunger by an arm 49. Due to the engagement of an extension 163 (Fig. 4, not shown) of a spring-urged member 59 by a tab 61 on the bell-crank lever 51, a detent 71 carried by the member 59 is aligned with an entrance slot 73 in the magazine. When the magazine has been fully inserted, detents 27, 29 engage in notches 31, 33 and allow the magazine to rest on the base 18, thereby closing a switch 111. The apparatus is provided with a manual control switch (cf. Fig. 9, not shown) and a switching arrangement such that on setting said control switch to an " advance " position, a film drive motor (not shown) connected to roller 57 is energized and solenoid 45 is de-energized, whereupon under the action of spring 75 and by way of member 59, the roller 55 is pivoted towards the driven roller 57 to begin feeding film out of the magazine. Movement of the member 59 adjusts its detent 71 in the slot 73 to lock the magazine in its cavity. Also at the same time, the locking-bar 83 pivots downwards to prevent raising of the magazine and microswitch 81 returns to its open position after stop S has been removed from the shoe 80. The magazine remains thus locked as long as film is payed out therefrom. The above referred-to film feed is effected against the opposing torque of a second (tendency drive) motor (not shown) applied to the core of the magazine through an opening (not shown) in the wall 18. With the manual control switch in a " neutral " position, the film drive motor is de-energized, and although the said second motor is still energized, its torque is insufficient to overcome the frictional resistance to motion of the payed-out film strip. On setting the manual control switch to a " reverse " position, the film drive motor is energized for rotation in the reverse direction, and the torque of the tendency drive motor is increased to return the film into the magazine. When the film is fully returned, stop S engages shoe 80 and closes switch 87, thereby energizing solenoid 45. Consequent attraction of plunger 47 moves members 55, 83 and 71 into positions such that the magazine may again be removed. A full description of the electric control circuit for the above operations is given in the Specification with reference to Fig. 8 (not shown).