Patent GB-547943-A (GB)
Title: Improvements in and relating to apparatus for x-ray serial radiography
IPC: G03B42/02
Filed: 1940-12-16
Abstract: 547,943. Radiographic apparatus. GENERAL ELECTRIC CO., Ltd., and CALDWELL, J. T. Dec. 16, 1940, No. 17751. [Class 98 (i)] In an X-ray photographic apparatus a movable holder receives a casette from a magazine and carries it to the exposure position after which it delivers it to a magazine for exposed casettes. The apparatus shown, which is intended for use with casettes of the kind described in Specification 547,944, comprises a frame 11 pivotally mounted on a cranked supporting arm 17 carried from the ceiling by counterweighted cords passing round a pulley 18, so that the frame may be raised and lowered. Secured to the frame 11, and extending to the left of it, are members 21, 22, which with a tie rod 25 form a rectangular framework for the reception of a detachable fluorescent screen (not shown). A movable casette holder is mounted on a carriage consisting of a plate 27, end posts 28, 29, and a bar 30, the lower ends of the posts being hooked to engage in a channel section rail 24 on which the carriage slides. The casette holder comprises vertical frame members 31, 32, the former of which extends into an upper channel-section guide rail 23, and horizontal connecting bars 33, 34, forming a rectangular frame of slightly larger internal dimensions than the casette. By movement of the carriage, the casette holder may be brought opposite a magazine 47 from which it receives an unexposed casette, then into the taking position in the frame 21, 22, 25 from which the fluorescent screen has been removed, and finally opposite a magazine 57 into which the exposed casette passes. The magazines 47, 57 consist of rectangular frames carried by the frame 11 on opposite sides of the path of the casette holder and slightly off-set from one another in plan, Fig. 3. Inclined grooves 48, 44, 58, Fig. 2, respectively in the side walls of the magazine 47, the uprights 31, 32 of the casette holder, and the sides of the magazine 57, and forming virtually continuations of each other, receive pins 55 extending from the sides of the casettes, which are thus suspended, and tend to slide from the magazine 48 to the holder, and from the latter to the magazine 57. Movement of the casettes from the magazine 48 is normally prevented by vertically slidable gate members 49, 50 which cover the ends of the grooves 48. When the casette holder is opposite the magazine, pins 53 on the carriage engage cams 51, 52 at the bottom ends of the gate members which are thus raised to bring notches in them into registry with the grooves 48, 44, a casette then sliding into the holder from the magazine. The casette is retained in the holder by gate members 35, 36 on it, which are similar to the members 49, 50, and are raised to release the casette when the holder is opposite the magazine 57 by the engagement at this time of cams 39, 40 with fixed abutments. The carriage is moved by a knob 65, the spindle of which passes through a slot 69 in the wall of a lateral extension of the frame 11. To ensure that the movements are carried out in correct sequence, a pivoted latch 81 co-operates with the knob spindle, the co-operating parts of the latch and spindle being so formed that when the casette holder is moved from its extreme right-hand position, in registry with the magazine 57, it is arrested by the latch when opposite the magazine 58 and is locked against movement in either direction. On pulling the knob outwardly the holder may be moved only to the left, to the exposure position, and on the return movement the latch allows the holder to move to the end of its travel, into registry with the magazine 57, completing the cycle. To give warning that the magazine 47 is empty, the magazine 57 may be of such depth that the last casette to be discharged from the holder cannot fully enter it, thus locking the holder in the unloading position. A pair of switches operated by a cam 90 carried at the top of the casette holder control the tube circuits so that the tube is (a) de-energized when the casette holder is opposite the magazine 57, (b) energized suitably for screen examination when the holder is in loading position and (c) energized suitably for radiography as the holder moves to exposure position. The exposure is indicated by a switch closed by a bell-crank lever 102 when the latter is engaged by the spindle of the knob 65.