Patent GB-930549-A (GB)
Title: Improvements in or relating to x-ray diagnosis apparatus
IPC: H05G1/46
Filed: 1959-11-13
Abstract: 930,549. X-ray diagnosis apparatus. SIEMENS-REINIGER-WERKE A.G. Nov. 13, 1959 [Nov. 14, 1958], No. 38643/59. Class 98 (1). X-ray apparatus comprising means for protecting the tube from overloading is arranged for either " three-knob " control, in which case the applied voltage, the current, and the exposure time, are all adjustable independently, or for " two-knob " control, in which case the voltage is adjustable independently, the other control adjusting the product of current exposure: for " two-knob " control, a clutch is engageable between the voltageadjusting control and the currentadjusting control, said clutch being disengaged when " three-knob " control is required. In the form shown in Fig. 3, knob 21 on spindle 22 controls the exposure time of a time switch 27 via a series of contacts 25 and resistance 26. Knob 41 on spindle 42 controls the tube voltage via a tapping 43 on a potentiometer 44. Knob 55 on spindle 49, which is connected to spindle 25 through gearing 36, controls the heater current via tapping 53 on potentiometer 54. Rotation of spindle 42 is also transmitted via gear-wheel 45 and toothed segment 47 to a disc 46 carrying brake pins 48 which bear against a disc 50 fixed to spindle 49. Discs 46, 50 act as a clutch arrangement, so that rotation of spindle 42 is transmitted to spindle 49 and sun-wheel 37, and hence through the differential gearing 36 to spindle 52 and tapping 53. Spindle 22 carries a disc 29 having a slot 30, in which slot is guided one end of a lever 31 attached at its other end to the spindle 32 of the two planet wheels 34, 35 of the differential gearing. Thus in "two-knob" operation, rotation of knobs 21 and 41 also acts on the differential gearing so as to effect a resultant rotation of the tap 53. This tap can be adjusted directly by knob 55, frictional conditions being arranged so that such rotation is not transmitted back to spindles 42 and 22. The correlation is such that, with regard to the adjusted operating values of voltage and time, the maximum permissible tube current is obtained. If it is not desired that the limit load is to be always adhered to, the current can be reduced by adjustment from knob 55. A pointer 59 indicates on a scale 58 the percentage of maximum permissive load applied. A pin 56 fixed to disc 50 moves in a slot 57 in disc 46; its position along this slot is determined by the said percentage, and the limits of movement allowed by the slot prevents loading the tube beyond the limit. Spindle 49 ends in a head 60 having two slots at right-angles, one deeper than the other. A pin 63 fixed within knob 55 rests in one of these slots. When it rests in the deeper one, the action of a spring 64 causes the lower surface of knob 55 to press sufficiently hard against disc 46 to effect coupling with disc 50 in the clutch action already described, and the apparatus is set for " two-knob " operation. To change over to " three-knob " operation, the knob 55 is lifted and turned through 90 degrees so as to dispose pin 63 in the less deep slot. The effect of spring 64 is thus reduced in such manner that the coupling between discs 46 and 50 is eliminated. In this case, also, the lifting of disc 46 closes a switch 66 which energizes a coil 67 operating a brake disc 68 fixed to spindle 52; thus the latter is no longer affected by rotation of spindle 22. The three freely adjusted values are indicated by scale pointers operated by cord pulleys 70, 71, 72 respectively.