GB638905A - Improvements connected with sphygmometers - Google Patents

Abstract

638,905. Sphygmographs. DEPOIT, E. J. L. Aug. 29, 1946, No. 26011. Convention date, Aug. 22, 1944. [Class 81(ii)] [Also in Groups XVIII, XIX and XXXVIII] Arterial pulsations in a chamber 1a, Fig. 1, of a pneumatic cuff 1c, are detected by a pneumatic cell 2a, converted to voltage variations by a moving coil or selenium cell device 190 and passed to a recorder 6 through a thermionic amplifier 5. The cuff preferably has a separate constricting chamber 1b and the constrictive pressure is registered by a mercury manometer 7 provided with a series of electric contacts producing signals on passage of the mercury meniscus which actuate a type wheel 8, step by step, to record the pressure opposite the corresponding part of the pulsation graph on a moving strip M marked in time intervals. By means of a uni-directional rotary control switch a motor 3a driving the air compressor 3 and strip feed is started and valves and switches operated to produce a graph 126 of pulsations under constrictive pressure rising rapidly and further rotation of the switch produces a record 127-130 of pulsations under a slowly falling constrictive pressure, and the strip is dated and severed as the switch is turned to the " stop " position. Adjustment is provided for varying the sensitivity of the pulse recording mechanism, and the apparatus can be mounted on a stand for coin-freed actuation, the cuff 1c, Fig. 3, being secured to the top of the stand and .tightened or released by a spring-loaded pull rod 15. The Specification as open to inspection under Sect. 91 comprises alternative pulsation detecting means such as variable resistances, piezo-electric crystals, variable condensers, moving armatures and hot-wire devices, and alternative magnetomotive operating arrangements for the recording device. This subject-matter does not appear in the Specification as accepted.