Patent GB-480459-A (GB)
Abstract: 480,459. R÷ntgenray apparatus. WATSON, W. Oct. 22, 1936, No. 28684. [Class 98 (i)] Apparatus for the production of radiographs comprises a turnable table for the reception of the body to be investigated and a carrier for supporting a screen or cassette located so as to intercept X-rays passing through the body, the said carrier being turnable about an axis which is parallel to that about which the table may be turned, and there being a connection between carrier and table such that upon turning the table the plane of the cassette or screen remains parallel to a particular plane of the body located on the table, which latter plane includes the axis of rotation of the table. Only a section of the body corresponding to this plane will, for reasons explained in the Specification, be photographed if the turning movements are carried out during an exposure. Fig. 1 is a side elevation of one modification and Fig. 2 a horizontal section on the line II-II of Fig. 1. Figs. 9 and 10 are respectively a vertical section and plan of the device indicated generally at 93 in Fig. 2. The base 19 carries a turntable 17 with guides 53 for a table 50 on rollers 52. On the lugs 15 and 16 are pivotally mounted the bearing units 11 and 12, in which are slidably mounted, but clamped by handles 56, the horizontal members 5 and 6 of two vertical tubular frameworks with vertical members 1 and 3, 2 and 4. Horizontal straps 8 are pivotally attached to the members 1 and 2, and 3 and 4. That between 1 and 2 carries a spring box 10 which balances the weight of the vertically slidable carriage 30 carried between bearing units 28, 29 pivotally mounted on sleeves which may be clamped to the tubes 1 and 2 by handles 31A. A cross-strap 20 connecting the lower ends of the tubes 3 and 4 has a central bearing 21 seated on a spigot attached to the foot 23 slidable between rails 24. These connections constrain the vertical frameworks to move parallel to themselves as the table 50 is rotated. The motive power for rotation of the table 50 during an exposure is supplied by the springs 34 attached at one end to the link 33 and at the other to a block 35 sliding in guides 36. The block 35 is engaged under a catch 37 lifted for the purpose by a rod 39 and pedal 40. The table is rotated to tension the springs and then released. The movement is controlled by a plunger 45 connected to the lug 16 by the rod 43, and moving in an oil-filled cylinder 44. A byepass 46 with valve 47 controls the oil flow. The carriage 30 has lazy-tong levers (not shown) to accommodate the different thicknesses of a fluorescent screen and a cassette and carries a Bucky grid which is moved vertically during the rotation of the table 50 by a system of levers (not shown) actuated by the pivoted lever 67, 68 engaging a cam 65 attached to the sleeve clamped to the pillar I. The device shown in Figs. 9 and 10 comprises two semicircular plates 94, 95 attached to the cross-strap 20 and provided with a series of apertures 96 to receive two pegs 104, 105. The base 97 attached to the sliding foot 23 carries a switch 98 successively operated to switch the tube on and of by the action of the pegs 104, 105 on the star wheel 100. The pawl 103A on the pillar 103 coacts with the end of the peg 105 projecting below the plate 95 to retain the apparatus in the position with the springs 34 extended. The pillar 101 carries a shock absorber arm 102 which engages the end of the peg 104 projecting above the plate 94 to stop the movement of the apparatus. The range of the movement may be varied by choosing different apertures for the pegs 104, 105. Stereoscopic pairs of photographs may be obtained by making two exposures with the table 50 in different positions (without continuous rotation). Scales may be provided, to measure the movement of the members 5 and 6 in housings 11 and 12, for use in localizing work.