GB336953A - - Google Patents

Abstract

336,953. British Thomson-Houston Co., Ltd., (Victor X-Ray Corporation). July 18, 1929. R÷ntgen-ray apparatus.-Apparatus for stereoscopic work comprises power-driven means for moving the tube from one position to another with an automatic declutching of the drive and brake application at the end of the pre-set movement, so as to obtain a steady and smooth movement. As shown, the tube 14, Fig. 1, and power-drive (e.g. an electric motor 41) are carried by a block 40 on a counterbalanced sleeve 11, which is fitted with anti-friction rollers 12 and moves on a vertical pillar 10. The movement is obtained by a pinion 55, Fig. 2, which is driven by a retractable spring clutch 48, 49, Fig. 6, and engages a graduated rack bar 33 mounted at one end on a collar 27 which is adjustable on the tube 10. The bar 33 carries an adjustable declutching arm 36, and its lower end, which extends through bearings 56 on the block 40, has a pin limiting the movement relatively to the block 40. The lower end of the bar also carries an insulated finger 59 which closes the normally-separated contacts 60, 61, on the block 40 when the apparatus is preliminarily set. An electromagnetic trigger 64 for effecting the position change of the sensitive plate carrier 19 is arranged in series with the contacts 60, 61, and in parallel with the motor 41. For operating, the film carrier 19 is centered relatively to the patient, the distance from a reference point (e.g. the ground) being indicated by a scale 70 and pointer 71. The sleeve 11 is set for the first exposure by a scale 72 on the tube 10 and a sliding link 73 on the sleeve 11. The rack bar 33 is adjusted and clamped by the collar 27 in intial position, thereby closing the contacts 60, 61. The arm 36 is set by the scale on the side of the bar 33 for the required tube shift. On starting the motor by the hand switch 62 after the first exposure, the plate shift mechanism is actuated by the electromagnet trigger 64, this circuit however being immediately broken by the separation of the contacts 60, 61 as the sleeve 11 rises. At the end of the pre-set shift, the arm 36 engages a lever 52 which is pivoted on the block 40 and has a fork extension 54 operating to slide a washer 65, Fig. 6, to declutch the plates 48, 49 and apply a friction brake 65, 66 to stop the tube movement.