Patent GB-1009576-A (GB)
Title: Heart massage apparatus
IPC: A61H31/00
Filed: 1964-02-10
Abstract: 1,009,576. Heart massage apparatus. WESTINGHOUSE ELECTRIC CORPORATION. Feb. 10, 1964 [Feb. 21, 1963; March 19,1963; April 19, 1963], No. 5454/64. Heading A5R. Heart massage apparatus includes a frame comprising a base 2 and a column 3 projecting upwardly therefrom, the column supporting a heart massage cylinder 7 with a fluid-operated piston 30 having a massage member 9a for compressing the patient's chest, the cylinder extending axially in a direction perpendicular to the plane containing the base, and the shortest distance of the massage member from the plane, and the distance from the column of a point of projection of the massage member on the plane, being sufficient to accommodate at least one side of the patient's chest. Control means for reciprocating the heart massage piston 30 in the cylinder 7 includes three similar spool valves 150, 160, 170 each having a position in which a communication 20 between a supply port 21 and a delivery port 22 is established against a spring 190, and a position in which a communication 23 between the-delivery port 22 and an exhaust port 24 is established by the spring 190, one of these communications being interrupted when the other is established. Compressed gas is supplied from a source 108 through a regulator valve 11 and the first spool valve 170, under the control of means 80 for determining the mode of operation of the device, to the supply port of the second spool valve 160, the delivery port of which is connected to the cylinder 7. The compressed gas source is also directly connected to the third spool valve 150 the delivery port of which is connected to a control chamber 112 of the second spool valve. For pneumatic automatic operation of the device, the first spool valve 170 is held by a plunger 83 and push rod 85 so that its communication 20 is permanently established, the second spool valve 160 being reciprocated under the control of the third spool valve 150 which is supported by a lever 45. With the communication 20 of the third spool valve established, gas is supplied through a throttle and check valve 79, 78 to a cylinder 50 and moves a piston 55 and a head 57 carried thereby to pivot the lever 45 anticlockwise. When a toggle arm 37, which bears against a stem 38 of the valve 150 and is mounted in a housing 36 also carried by the lever, contacts a selected one of a series of stops 64a-64d of different lengths, it is tripped through its dead-centre position to release the spool stem 38 and permit the communication 23 to be established. Gas is then vented from the control chamber 112 of the second spool valve and the cylinder 50 through check and throttle valves 76, 77 and the second spool valve moves to establish its communication 23 venting the heart massage cylinder so that the plunger head 9a releases the patients' body. The piston 55 and the head 57 then reverse to permit the lever 45 to be pivotted clockwise by a spring 53. On engaging the stop 60, the lever 37 is again tripped and bears against the stem 38 of the third spool valve to establish its communication 20 so that gas under pressure is supplied to the control chamber of the second spool valve. The second spool valve then moves so that gas under pressure is supplied to the heart massage cylinder 7 and the plunger head 9a makes a compressive stroke against the patients' body. The frequency of the cycle of operation is determined by the distance between the stops 60 and 64a-64d. The ratio of the periods in which gas is supplied to and released from the heart massage cylinder is determined by the relative settings of the throttle valves 77, 79. For controlling the device electrically or manually, stops 64a-64d are replaced by a flat surface 73 which is never reached by the toggle arm 37, so that the second and third spool valves have their communications 20 permanently established. Gas supply to the heart massage cylinder is then controlled by reciprocation of the spool of the first spool valve 170 either manually through the push rod 85 or electrically by a solenoid 81 which is alternately energized and de-energized e.g. by the patient's electrocardiograph R-wave. The massage cylinder is slidable downwardly in the frame, upward movement normally being prevented by a tab pivotal downwardly by a spring and having a square aperture which bites into the cylinder if upward movement is attempted without depressing the tab.