GB705285A - Improvements in or relating to x-ray apparatus - Google Patents

Abstract

705,285. X-ray apparatus. FRASER, F. April 25, 1952 [April 26, 1951], No. 9765/51. Class 98(1) An X-ray apparatus has attached thereto a pair of light beam projection devices which are mounted with their centre lines in a common plane which also contains the centre line of the X-ray beam, and the devices are spaced apart and so directed that the projected beams intersect at a point on the centre line of the X-ray beam at a desired distance from the X-ray tube. Preferably, the devices are on opposite sides of the X-ray tube. The devices may have means for moving them angularly and simultaneously in their common plane so that the position of intersection may move along the centre line of the X-ray beam. As shown, tubes 19, 20 are trunnioned in brackets 17, 18 at opposite sides of the casing 10 of an X-ray tube. Electric bulbs 27, 28 are mounted in tubes 23, 24 which are slidable telescopically on tubes 19, 20 and fixed thereon with the bulb at a distance from lenses carried by detachable rings 21, 22 just greater than the focal lengths. Rods 33, 34 have cranked ends threaded into collars 31 which fit tightly on tubes 19, 20 and locked by lock-nuts. The cranked ends are journaled in hollow nuts 40, 41 threaded in brackets 17, 18. At the other sides of the brackets stubs, threaded into collars 31, are similarly journaled in hollow nuts. Rods 33, 34 have bentover ends engaging a peripheral groove in a disc 45 fast with a screw 46 having a knurled head and threaded in a bracket 48 on casing 10. As the screw 46 is turned, rods 33, 34 and tubes 19, 22 are rocked simultaneously and to the same extent. The end of rod 34 engages a slot in a lever 52 pivoted at 53 to a plate 54 and fast with a pointer 55 moving over a scale of distances on plate 54. When the apparatus is properly adjusted, screw 46 is turned until pointer 55 indicates the required distance, and the beams from tubes 19, 20 then intersect at a point on the central axis of X-rays and at the distance from the X-ray tube indicated by pointer 55. Screw 46 may be replaced by an axially slidable member.