Patent GB-747570-A (GB)
Title: Improvements relating to x-ray diagnostic equipment
Inventor: FLEURY GEORGE ROBERT
IPC: G03B42/02
Filed: 1953-07-17
Abstract: 747,570. X-ray apparatus. METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. July 19, 1954 [July 17, 1953], No. 19932/53. Class 98 (1). X-ray apparatus consists of a rectangular main frame carrying a fluorescent screen at one end, a sub-frame adapted to receive a cassette of a maximum size movable along the main frame between positions under and clear of the screen, an adaptor for supporting a cassette of less than maximum size in the sub-frame so as to be centralized with respect to the screen when in position under the screen and a " serial " adaptor with a selectivelyoperable stop or stops for permitting serial radiography with a cassette of less than the maximum size supported in the sub-frame by means of the adaptor, the stops operating to centralize two or more adjacent areas of the cassette sequentially with respect to the screen. As shown in Fig. 1, a rectangular main frame has side members 1 and end members 2, 3. A thin sheet 4 of X-ray transparent insulating material is mounted at the underside of the frame, and a fluorescent screen 5 is hingedly mounted at one end of the frame. A sub-frame 5, carrying an X-ray cassette, is slidable in guides between a position under the screen 5 and a position clear of the screen by means of a handle 56 on a rod 55 attached to the sub-frame. A Bucky grid is removably mounted in a carriage 8 slidable in guides in the frame to and from a position under the cassette when the latter is under the screen. A further set of tracks under the sheet 4 carries a masking plate movable into or out of register with the screen. A pressure cone may be mounted on the masking plate. Adjustable shutters (not shown) may be mounted below the screen, just above the sheet 4. The sub-frame 5, Fig. 3, has side members 12 and end members 13, 14. Corner pieces 17 support plates 15, which support a cassette inserted in the sub-frame from below, and top plates 16 formed with retaining lips 161, 16<SP>11</SP>. A cassette may be placed in the sub-frame either with its longer sides perpendicular to sides 12 and engaging the lips 16<SP>1</SP>, or with its longer sides parallel to sides 12 and engaging the lips 1611. The cassette is held in place in either position by spring-loaded fingers 18 which bear on one of its longer sides. The sub-frame may receive instead an adaptor in which a cassette of smaller size is mounted. The adaptor, Fig. 4, consists of parallel spaced bars 26, with perpendicular bars 21 slidable thereon. Bars 21 are located by spring catches, releasable by knobs 23, which engage holes or notches 24 in bars 26. Bars 21 are of L-section and carry slidable angle pieces 22, similarly located by spring catches, to engage the cassette, which is held in place as by pivoted arms 28. As an alternative, a number of adaptors may be provided, each receiving one of the smaller sizes of cassette. Another adaptor enabling the apparatus to be used for serial radiography is shown in Fig. 5, and consists of a frame 29, 30, 31, 32 into which a cassette may be inserted and held between plates 33, 34, 36, 38 by bow springs 35. A unit 39 attached to the frame carries runners 43, which, together with other runners 43 on the frame, enable the adaptor to be mounted in sub-frame 5. Stops 41 are adjustably mounted on unit 29 by screws 40, and have a snap action movement between an operative position and an inoperative position, respectively perpendicular and parallel to the plane of the cassette. When the adaptor and sub-frame are moved to the left in Fig. 1, the leading stop 41 engages a fixed stop (not shown), on the main frame and, in co-operation with a back stop 42, arrests the sub-frame in proper position for the first exposure. Stop 41 also engages a latch (not shown) on the main frame and is thereby retracted on return movement of the sub-frame. The second stop 41 similarly locates the sub-frame for the second exposure, and the full movement of the frame to the left with both stops inoperative provides proper positioning for the third exposure. The serial radiography adaptor may be arranged to receive cassettes of various sizes, and to expose areas extending over only a part of the transverse dimension of the cassette. The main frame may be supported by a linkage enabling it to be moved to a vertical position on a support adjustably mounted an X-ray table; an X-ray tube may also be mounted below the table on the support. Movement of the parts may be locked by electromagnetically-operated brakes. Hand-grips 49 (Fig. 1), on the main frame may incorporate switches which, when the grips are pressed to move the unit, release the brakes and actuate motors which assist the movement. The main frame may also carry levers 53 controlling the adjustable shutter, push-button switches 54 for energizing the X-ray tube, and a switch (not shown) for determining the X-ray intensity. This switch may alter the intensity as appropriate for fluoroscopy or radiography on movement of sub-frame 5.