GB1090382A - Piston machine - Google Patents

Abstract

1,090,382. Reciprocating motors pumps and compressors. M. GLAS. Jan. 29, 1965 [Jan. 30, 1964], No.4048/65. Headings F1A, F1N and F1P. An hydraulic or pneumatic apparatus having a piston slidable in an open ended cylinder, axially movable into engagement with one or other of two spaced apart cover members to form a closed cylinder may be constructed to function as a single stroke motor, pump or compressor. The construction of Fig. 1 is a hydraulic single stroke motor. The motor comprises a piston 8 in a cylinder 4 axially movable by thrust pistons 35 into engagement with covers 2, 3 which form the end closure members of a cylinder jacket 1 radially spaced from the cylinder 4 to define an annular flow channel 1'. A pistod rod 7 secured to piston 8 is provided with two shoulders 21, 22 forming quick-traverse pistons disposed in respective cylinders 17, 18 provided in the covers 2, 3. Each cover 2, 3 is provided with two closed bores, in one of which is slidable a control piston 42 and in the other is slidable one of the thrust pistons 35. To cause the piston 8 to move to the left a distributing valve 27 is operated to direct pressure liquid from a source 27a to a port 25 in the cover 3 while connecting a port 28 in the cover 2 to a sump 276. Pressure liquid entering the port 25 flows through a throttle bore 38 to cause the thrust piston 35 to move steadily towards the cylinder 4. Liquid entering the port 25 also flows through a radial bore 41 to pressurize the quick traverse cylinder 18, and flows therefrom through a further radial bore 52 and passages 47, 51, 53 in the control piston 42 to a closed space 55 behind the piston 42. Pressurization of the cylinder 18 causes rapid movement of the piston 8 to the left, the resistance to such movement being negligible since liquid ahead of the piston 8 can flow freely through the annular channel 1' tothe space behind the piston. The pressurization of the space 55 causes the control piston 42 to move to a position in which ports 45 therein register with a port 44 leading to the quicktraverse cylinder 18, and hence the main cylinder 4 is pressurized therefrom. Before registration of the ports 44, 45, or soon after, the thrust piston 35 causes the cylinder 4 to engage the cover 2 to initiate the power stroke of the piston 8. Liquid trapped by the engagement of the cylinder 4 with the cover 2 flows to the sump 27 via a non-return valve 49, the cylinder 17 and the port 28. Reversal of the valve 27 causes an identical stroke in the opposite direction. The motor may be modified for pneumatic operation Fig. 2 (not shown) by replacing the control pistons 42 by check valve (73, 73') which control the flow to the cylinder 4 and which may be operated manually, by engagement with a workpiece, electromagnetically or hydraulically. The motor may also be modified for alternative hydraulic or pneumatic actuation Fig. 3 (not shown) in which construction liquid is sealed in the jacket (1) and is pressurized by fluid admitted by the control piston (142) to a subsidiary cylinder (185) having a piston provided with plungers which act to pressurize the sealed liquid. The thrust pistons which move the cylinder 4 may be omitted, Figs. 4 and 5 (not shown) and instead the cylinder may be moved directly by the action of fluid acting on the ends thereof which are disposed in annular chambers formed in the cover. The construction of Figs. 6 and 7 (not shown) is pump or compressor. The pump or compressor comprises a crank-shaft 692 arranged to reciprocate a piston 608 in a cylinder 604 having apertured end walls 609 and being slidable into engagement with a cover 603 or a cover 602 by thrust pistons 635. The crank-shaft 692 carries two identical camplates 695a, 695b disposed at 180‹ to each other and arranged to reciprocate a pair of control pistons 697a, 697b. During idling periods the cylinder 604 is maintained in a central position by a pair of spring-loaded plungers 691, and a slide-valve 699 is in a position in which fluid pumped by the pistons 697a, 697b flows to and fro between their respective cylinders 698a, 698b. The slide-valve 699 is controlled by an electromagnet 720 having a circuit which includes a master switch and switches 717, 718, 719 actuated by cam-members 716 and 719' on the cam-plate 695b, adjustable to vary the effective stroke of the piston 608. If the master switch is operated the switches 717, 718, 719 cause alternate energization and de-energization of the electromagnet 720. Energization of the electromagnet 720 moves the slide-valve 699 to its lower position and hence the control pistons 697a, 697b cause alternate operation of the thrust pistons 635 which thereby causes the cylinder to alternately abut the covers 602, 603 so that fluid trapped by movement of the cylinder 604 is pumped by the piston 608 past non-return valves 803, Fig. 7 (not shown) in the covers. Fluid is admitted to the space behind the piston 803 through inlets in the covers or through apertures (802) in a jacket 601 surrounding the cylinder.