Patent GB-709458-A (GB)
Title: Improvements in or relating to photographic roll film cameras
IPC: G03B17/30
Filed: 1952-02-07
Abstract: 709,458. Photographic roll-film cameras. KODAK, Ltd. Feb. 7, 1952 [Feb. 13, 1951], No. 3257/52. Class 98(1) In a camera in which a film spool inserted into a supply chamber is unwound by rotation of a winding shaft into a take-up chamber where it forms a loose coil exposure of the film being effected between intermittent rewinding of the film back on to the spool, a spring band for controlling rewinding movements of the film is uncoiled by operation of the winding shaft from a position adjacent the film supply chamber and coiled up in a take-up chamber and permits latching means to become operative to prevent unwinding movement of the winding shaft after a chosen unwinding movement of the band while it renders the latching means inoperative on rotating the winding shaft in the opposite (rewinding) direction. Preferably the rewinding movement is interrupted intermittently by a latching device adapted to engage spaced apertures provided in the spring band. As shown, the film feeding knob 19 is secured to an axially movable shaft 11 which is located in either of two positions by a latch spring 22 co-operating with grooves 16, 17 on the shaft. One end 37 of a spring metal band 35 passes through a slot 38 in a sleeve 36 on which it is wound surrounding the shaft and is secured to a flat 15 on said shaft, said band extending across the camera into a chamber 47 in which the end of the band is always retained even in its fully rewound position by a pin 56 thereon engaging a shoulder 57 in said chamber. When the camera is unloaded, the shaft is maintained in its inner position by a spring 29 in a gtoove 30 in a member secured to the body 1 engaging in a groove 13 in the shaft and in this inner position the shaft is locked against clockwise rotation by a coil spring brake 23 surrounding the shaft and having an arm 24 engaging in one of a number of recesses between teeth 25 on a removable top wall 45 of the camera body. On loading a spool of films into the camera through the bottom of the chamber 5 closed by a hinged door 8 so that the triangular slot C in the spool flange F engages with the triangular portion 12 on the shaft, the arm 28 of spring 29 is moved to bring the spring out of engagement with the slot 13. The shaft may then be withdrawn to the Fig. 2 position disengaging the brake 23 and rotated clockwise to feed the film and spring band into the receiving chambers 6, 47. When the requisite length of film has been fed into the chamber 6, the band 35 has unwound almost completely so that a spring 40 positioned in a groove 41 in the sleeve 36 and having a vertical arm 42 located in a slot 42a in the flange of the sleeve and is held in the position shown by the convolutions of the band on the sleeve, is freed so that it can engage in a notch 44 in the body to arrest the rotation of the shaft. The shaft is then pushed inwardly re-engaging the brake 23 and the film is then wound back on to the spool until the band is arrested, by movement of a slidable plate 70 having a tooth 79 engaging in the first aperture 52 in the band to bring the right-hand end of a slot 72 therein against a stop pin 71. After an exposure has been made, a push button 76 on the removable camera back 50 is depressed against a return spring 77 to engage a flange 75 on the plate 70 and pivot the latter about the pin 71, disengaging the tooth 79 from the aperture 52 so that a spring 73 returns the plate 70 to the initial position shown, the tooth 79 riding along the band. The film may then be wound on until the tooth 79 again engages in a further aperture 52 in the band and arrests it as before. When the last exposure has been made, the end of the film is wound on to the spool without interruption, no more apertures being provided in the band, until the pin 56 on the band engages the shoulder 57 in the chamber 47. Exposure numbers 48 on the band may be viewed through a window 49 in the camera back at each arrest of the film during the rewinding operation. To avoid missed and double exposures, the button 76 may be replaced by a lever 80 engaging the apertures 52 in the band 35 and interconnected with the shutter release as described and claimed in Specification 709,460.