Patent GB-1016718-A (GB)
Title: Improvements in or relating to pumping equipment
Inventor: LIGHTOWLER LESLIE ERNEST
IPC: A61M16/00
Filed: 1963-05-29
Abstract: 1,016,718. Artificial respiration pumps. LAYCOCK ENGINEERING Ltd. July 30, 1964 [May 29, 1963], No. 21563/63. Heading AST. [Also in Division F1] An artificial respiration pump comprises an air cylinder 17 generated by a main piston 24 which is reciprocated by a motor piston 72 driven by compressed air supplied through a shuttle valve 51, and a pilot valve 81 operable by the motor piston to cause reversal of the shuttle valve and the motor piston, the rods of the main piston and the motor piston being interconnected by a link 27 pivotal on an fulcrum 30 which is adjustable so that the stroke of the main piston may be altered. The link 27 is mounted in a saddle 29 which is mounted on an adjusting bar 31 by means of a fulcrum pin 30. The adjusting bar is slidable in a slideway 32 fixed to the pump casing and is longitudinally threaded to receive a screw shaft 34. The position of the adjusting bar and the fulcrum is altered by a handwheel 44 connected by shafts and gears with the screw shaft 34. A slider block 46 on one 43 of the shafts carries a pointer which moves over a fixed scale calibrated in pump output as the handwheel is rotated. The pump cylinder 17 has at one end an outlet 21 for connection with the patient and exhaust holes 20 at the other end. The pilot valve 81 (Figures 6 and 7 not shown), which is located in a plug 86 closing one end of the motor cylinder 19, is reciprocable in a cylinder 84 and has a transfer groove 82 which, during the pressure stroke of the pump, permits compressed gas to flow via a conduit 103, pilot valve inlet 89 and outlet 93 to one side of the main shuttle valve via inlet 58, air from the other side of the shuttle valve being exhausted to atmosphere via outlet 62, a conduit 111, a record pilot valve transfer groove 83 and conduits 106, 107. Compressed air can then flow via a conduit 101, a transfer groove 52 in the main shuttle valve, a conduit 108 and a passage 98 in the motor cylinder plug 86 to one side of the motor piston. The resulting movement of the motor piston is transmitted by the pivotal link 27 to the pump piston to produce a pressure stroke. Air is exhausted to atmosphere from the other side of the motor piston through an outlet 97, a conduit 104 and an adjustable throttle valve 67. The rate of travel of the motor piston, and thus the pulse rate of the pump, is adjusted by regulation of the throttle valve. A rod 78, resiliently connected at one end to the motor piston, extends through the pilot valve and has a nut 90 (Figures 6 and 7 not shown) on the other end. As the motor piston reaches the limit of its movement producing the pressure stroke, the nut reverses the pilot valve. To produce an exhaust stroke, compressed air flows via another pilot valve transfer groove 83 to cause reversal of the shuttle valve 51. Compressed air then flows from the conduit 101 via another shuttle valve transfer groove 53 and a conduit 112 to the other side of the motor piston, which is thus reversed and causes reversal of the pump piston. At the limit of its movement producing the exhaust stroke, a bearing 79 on the motor piston engages a spring 87 to cause reversal of the pilot valve for initiating the next pressure stroke. Air vented from the motor cylinder during the exhaust stroke also passes through the throttle valve 67.