Patent GB-665728-A (GB)
Title: Improvements in or relating to x-ray apparatus
IPC: A61B6/00
Filed: 1949-05-02
Abstract: 665,728. X - ray apparatus. WESTING- HOUSE ELECTRIC INTERNATIONAL CO. May 2, 1949 [May 29, 1948], No. 8285/51. Divided out of 665,692. Class 98 (i). The apparatus comprises a table 21, Fig. 1, pivoted on a base 31 and swingable through 180 degrees so as to lie horizontally while exposing one side or the other or to stand in a vertical plane, support means on the table for an X-ray tube 23 and an associated fluorescent screen 69, a screen counterbalancing assembly mounted on the support means and comprising a hollow column 72, a compression spring housed in the column, slotted members confining and adjusting the compression of the spring, a rod movable in the spring and carrying transverse pins, one of the spring-confining members carrying a guide for one of the pins, an arm carrying the fluorescent screen and pivoted to the column intermediate its ends, a collar rotatable on the rod, a knob and pointer assembly secured to the end of the rod beyond the collar, means pivotally connecting one end of the screen-carrying arm to the collar, the knob serving to turn the rod to adjust it with respect to the slotted spring-confining members, whereby the screen may be released from the spring and allowed to move freely in vertical fluoroscopy, balanced by the spring for horizontal fluoroscopy, or locked to prevent it dropping on the floor when the apparatus is used for horizontal radiography. The support means may consist of a carriage 26 movable on longitudinal tracks attached to the table, and a second carriage movable transversely in tracks on the carriage 26 and supporting column 72 and X-ray tube 23. The tube 72, Fig. 7, contains a spring 73 trapped between plates 74, 75. Plate 74 is fixed on threaded rods (not shown) fixed to an end-plate 79, by which the compression of spring 73 can be adjusted, while plate 75 rests on a spacer tube 76 fixed within the lower end of tube 72. An arm 87 supporting the screen is pivoted at 102 to lugs on tube 72 and has a forked end pivoted to a block 103 carrying a dial 92. A rod 86, with a knob 89 and pointer 88, passes freely through block 103, a slot 100 in the closed top of tube 72, and slots in plates 74, 75. A spring 104 presses block 103 against knob 89. Rod 86 has short cross-bars 93, 94 which pass freely through the slabs in plates 74, 75 in certain angular positions of the rod. When the apparatus is used for fluoroscopy with the table horizontal and the screen uppermost (as shown in Fig. 7) rod 86 is turned by knob 89 to a position indicated by pointer 88 such that bar 93 passes freely through a slot in plate 74, but bar 94 lifts plate 75 to compress spring 73 when the screen is moved downwards, thus counterbalancing the screen. Before turning the table to its second horizontal position, the screen is moved downwardly until bar 93 is above plate 74. Knob 89 is then turned to a second position, wherein neither bar can pass through a plate. When the table is turned to its second horizontal position for radiography, the screen is thus held in a fixed position clear of the floor. When the table is to be used in a vertical position, knob 89 is turned to a third position in which bar 93 passes through a second slot, at an angle to the first, in plate 74, and bar 94 passes through a slot in plate 75 to slide freely in a guide 98. In this position spring 73 has no effect. Specifications 665,692 and 665,729 are referred to.