Patent GB-1295967-A (GB)
IPC: G03B42/04
Filed: 1970-03-26
Abstract: 1295967 X-Ray film cassettes MINNESOTA MINING & MFG CO 26 March 1970 [29 March 1969] 14899/70 Heading H5R An X-ray cassette that may be automatically loaded and unloaded by cassette-handling apparatus housed in a lighted room includes a casing having top and bottom plates 11 and 12 and a slot in edge wall 16 closed by a spring- urged flap, the X-ray film being held in the casing between a pair of panels, and the casing including an opening for receiving an actuating pin 38 of the cassette-handling apparatus, such that cyclical movement of the pin moves the panels with the film, from an exposure position to a position in which the panels extend through the slot, and back again to the exposure position. When in the cassette, the film is held between panels 20 and 21 which are caused to move together by mating tabs 26 and notches 27, and which carry on their facing surfaces intensifying screens and a layer of lead foil (23 and 25, Fig. 3, not shown). The panels are spring-urged apart by interposed leaf springs 30, and spring-urged together, with greater force, by opposed sets of pressure pads 31 on the lower panel 21 and 32 on the lower casing plate 12, which register with one another when the panels 20 and 21 are in the fully inserted position. To withdraw an exposed film from the cassette, the latter is placed on an apertured table with its slotted end inserted through a flap of an unloading apparatus (Figs. 4 to 6, not shown) which includes a pair of nip rollers for gripping and withdrawing a film, an actuating pin 38, Fig. 7, projecting through apertures in the table, the casing lower plate 12, a slide member 43 that slides between a pair of guide rails on the plate 12, and a multi-armed lever 44 pivoted to the slide member 43 by stud 45. In the film expose position shown in Fig. 1, the lever 44 is urged clockwise by spring 50 such that arms 51 and 57 extend through respective openings 52 and 58 in the two guide rails, to lock the slide member in the cassette, while a further arm recessed to form parallel jaws 54 and 55 engages a pin 56 that is fixed to the lower panel 21. To unload the cassette, the actuating pin 38 is moved forward whereby, since it is located at the end of the slot 47 in lever 44, but spaced from the end of the corresponding slot 46 in the slide member 43, lever 44 is first rotated against the action of spring 55 to disengage arm 51 from the guide rail, and thereafter moves both the slide and the panels 20 and 21 towards the slotted end of the casing, causing pressure pads 31 and 32 to move out of registry with one another, whereupon the lower panel drops down under the action of leaf springs 30, the pin 56 being received within an aperture in slide 43. With continued movement arm 57 reaches the end of opening 58 in the guide rail, at which position the panels 20 and 21 extend through the slotted end of the cassette into the unloading apparatus, whereafter lever 44 is cammed by engagement of arm 57 with the guide rail to disengage jaws 54 and 55 from pin 56. At this position, panels 20 and 21 abut against a post which retains them in this position, while with further forward movement of pin 38, slide 43, and lever 44, a U-shaped flange 63 attached to the slide 43 engages the corners of the film exposed by the cut-out portions 64a, 64b and 65a, 65b of the panels 20 and 21, and advances it so that its forward end is caught between a pair of nip rollers in the unloading apparatus, and drawn out of the cassette. During reverse movement of the pin 38 to its original position, arm 57 engages opening 58, whereupon jaws 54, 55 engage pin 56, and the panels 20, 21 are returned to their original position within the cassette. The loading operation is similar. An indicator lever 70, pivoted to the bottom plate 12 and spring-urged against the edge of the film, if present, indicates whether the cassette is full or empty.