GB963223A - Timing device for the control of x-ray equipment - Google Patents

Abstract

963,223. Time switches. AMALGAMATED DENTAL CO. Ltd. Jan. 4, 1962 [Jan .5, 1961,] No. 550/61. Heading H2B. [Also in Divisions H3 and H5] A time switch operating a dental X-ray machine provides both a variable " on " period and a variable " delay " period between actuation of the mechanism and the commencement of the on period. The time switch has a spindle 4 rotatable by a knob 14 to wind a clock spring 13 and coupled by a pawl and ratchet drive 21, 22 to an escapement mechanism so as to return knob 14 slowly towards its rest position (pointer 15, as shown in Fig. 2). Spindle 4 also carries a cam 7 which operates contacts 12 when pointer 15 passes a zero position on the scale. A second knob 27 coaxial with the first adjusts the position of a cam surface 25 which disengages the drive 21, 22 by a roller 24 when the two pointers 15, 28 coincide. In use, pointer 28 on knob 27 is set to a position on the " X-ray " scale 17 and pointer 15 is set to a desired point on the " delay " scale 18. A latch 29 locks the escapement until a button 30 is depressed when the latch rotates and sets the clockwork in motion. Rotation of latch 29 also turns a cam 39 on the same spindle to close auxiliary contacts 40, the main contacts opening simultaneously. The clock moves the pointer 15 and as it reaches the zero cam 7 closes contacts 12 to energize the X-ray machine until the two pointers coincide when the drive 21, 22 is released, causing knob 14 to return to its rest position, a peg 23 resetting latch 29 and opening contacts 40. Further cams 5, 6 operate additional sets of contacts controlling indicating devices. In a second embodiment using an electronic time switch (Division H3), the indicator operates during the delay period up to a short fixed time before the X-ray discharge commences.