GB450874A - Improvements in and relating to shutters in or for x-ray tube installations - Google Patents

Abstract

450,874. R÷ntgen -ray apparatus. BANCROFT, F. E., 19, Delaine Road. Withing- ton, Manchester, and ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Crown House, Aldwych, London. Jan. 29, 1935, No. 2961. [Class 98 (i)] The opening and closing movements of an X-ray shutter are controlled by a flexible transmission member extending from the shutter to an electro-mechanical actuating means, the latter having electrical control means including a control member at a position outside the X-ray chamber. The applicator cylinder 1 has a box-like frame of brass or steel 3, and a pair of guide channels 4 secured thereto. The shutter, which comprises steel plates 5 with lead sheets 7 between, is secured to bars 6 which slide in the channels 4. A yoke 12 is secured to the ends of the bars 6, and to the inner cable 13 of the Bowden wire by means of an anchoring block 14. The outer sheath 15 of the Bowden wire is secured. to an anchoring bar 16. Helical springs 18 secured to the yoke 12 by pegs 20 actuate the shutter to its closed position. Indicating switches, e.g. 21, may be mounted on the guide frame 4 and may have their contact members actuated by engagement with the slide bars 6, a depression 24 in the latter closing the switches when the shutter is closed. The switches may also operate aural indicators. An electric motor 26 with reducing gear 27 rotates the output shaft 29 which has a crank 30 and block 32 secured to the end of the cable 13 operating the shutter. The outer sheath 15 of the cable is adjustably anchored to a block 34. A friction brake comprising friction discs 44, 45 and operated electromagnetically, is connected in the energizing circuit of the motor, springs 52, 54 applying the brake when the motor is unenergized. The shaft 29 carries an insulated cam 35 which co-operates with spring members 36, 37 carrying contacts co-operating with contacts on fixed members 39, 40. The contacts 36, 37 and 39, 40 under the action of the cam 35 constitute limit switches, which de-energize the motor and the coil 51 at the extreme positions of the shutter. Push buttons are connected across the contacts to short circuit the limit switches and start the motor. An electric or other time switch may control the period of operation of the shutter. Interlocks ensure proper closing of the shutter, the resetting of the time switch and its operation upon failure of the current. Specification 415,723 is referred to.