GB926739A - Therapeutic apparatus - Google Patents

Abstract

926,739. Electro-therapeutic apparatus. DIAPULSE MANUFACTURING CORPORATION OF AMERICA. Sept. 20, 1960 [Oct. 2, 1959], No. 32308/60. Class 81 (2). Therapeutic apparatus for administering pulsed high-frequency oscillations comprises a treatment head, movable to a position adjacent the desired part of the body and means for controlling the oscillation generator to determine the magnitude of the energy output. The apparatus is enclosed in a cabinet 5, Fig. 1, provided with controls 59, 36, 62 and having, at one side, an adjustable arm 7, at the free end of which the treatment head 9 is carried on a universal mounting. The main switch 15, Fig. 4, has " off," '' standby," and "operate" positions and when turned to the central position the supply mains, connected at L1, L2, cause energization of relay 16 which connects the supply to the power transformers 20, 21, 23, 22, supplying respectively heater current, grid bias voltage, H.T. for the oscillation valves and heater current for the rectifier valves 28, 29. After a delay dependent on a thermal switch 30, which actuates a relay 32, the 420 volt H.T. from transformer 21 is connected to the oscillation generator valves 74, 64 and mains are connected to the transformer 23 to supply 2100 volt H.T. to the output valves 88, 89, 90, 92. Moving the main switch to " operate " merely cuts-out a timing switch 34 which would otherwise switch-off the high tension supply after a predetermined interval. In the oscillation generator section 12 a crystal 70, energized through a valve 74 and tuned circuit 72, 73, oscillates at 6.78 mc/s. and its second harmonic is fed to a control valve 64, the purpose of which is to pass the oscillations in the form of pulsed bursts of oscillation, the pulse repetition frequency being determined by two valves 68, 78, connected as a cathode coupled multivibrator, through a coupling valve 83. Thereafter, the fourth harmonic, at 27.12 mc/s. is selected by a tuned circuit 85, 86, 87 and fed to power amplifier valves 88, 89, 90, 92, connected as two pairs in push-pull. The output is thence fed through a low-pass filter 97A to the tuned radiating coil 100 which is mounted in the treatment head. The period of operation of the multi-vibrator, and thus the ratio of pulse length to repetition frequency, is determined, by the voltage applied to the grid of valve 68 through a selector switch 60 while the amplitude of the oscillations passed to the output stage, and thereby the degree of penetration attainable by the output radiator, is controlled by the voltage applied to the screen grid of tube 64, through an adjustable switch 68.