GB484604A - Improvements in apparatus for producing intermittent venous occlusion - Google Patents

Abstract

484,604. Massage appliances; tourniquets. U.M.A., Inc. Nov. 9, 1936, No. 30528. Convention date, Nov. 7, 1935. [Class 81 (ii)] [Also in Group XXVIII] An apparatus for increasing blood circulation through an extremity by intermittent occlusion of the venous circulation comprises a pneumatic cuff' for encircling the part, and means for inflating the cuff to a pressure intermediate between that of the venous and arterial circulation, said means being automatically controlled so that the cuff is repeatedly inflated, held at the given pressure for a short period, deflated to atmospheric pressure and so retained for another short period. A cuff 1 of usual design has a port 2 connected to an air compressor 6, driven by a motor 7 and to a release valve 21, 22 operated by an arm 30 of a relay armature 31, 32. The armature is moved into pressure-releasing position by an electromagnet 40 energized by a circuit including a switch 44, the actuating member 50 of which when moved to close the circuit acts through an extension 51 mechanically to open the release valve. The circuit of the electromagnet 40 is energized from a source of alternating current through leads 45, 61, the lead 61 having a contact 62 which bears on rotating metallic disc 63 on which is mounted a disc 65 of insulating material having spaced gaps. A contact 64 connected to the electromagnet bears on the gapped portion of the insulating disc so that as this rotates the circuit is alternately made and broken. The discs are rotated conveniently by a synchronous motor 67 or a clockwork motor. The circuit of the motor 7 is controlled by the rotating disc through a magnetic relay 81, 82 in the required relationship with the release valve and is further controlled by a mercury pressure gauge 92 into which dip contact wires 91, 93 connected to the circuit. The wire 91 is adjustable so as to vary the pressure in the tube 97 (and the cuff of the device) which is reached before the mercury column leaves the wire 91 and breaks the circuit of the motor 7 and stops the pump. Indicator lamps 103- 105 are provided in the circuit.