GB1022577A - A multiple piston distributive pump with hydraulic system for the synchronized operation of a plurality of working cylinders - Google Patents

Abstract

1,022,577. Hydraulic machines; reciprocating pumps. H. BIERI AND SOHN. May 14, 1963 [May 14, 1962], No. 19165/63. Headings F1A and FIP. The return stroke under load of each of a plurality of hydraulic piston and cylinder units 13, 12 Fig. 1 (not shown) arranged in pairs is effected synchronously by withdrawing measured quantities of hydraulic fluid e.g., oil from the cylinders by a pump having a piston and cylinder unit for each hydraulic unit and which ejects fluid against an elevated pressure. Each pump piston 4 Fig. 2 (not shown) is driven by a plunger 5 actuated by a common eccentric 2 driven by a motor 1 and the stroke is varied by a screw cap 22 bearing on a shoulder 25 of the plunger 5. Outward displacement of a piston 13 against load is effected by fluid forced by associated piston 4 past a non-return valve 7, a blocking valve 8, lines 9, 10 leading to chamber 11 and fluid from the other side of piston 13 is returned through lines 47, 39 a pressureretaining valve 40, a line 20 connected to the delivery side of a low pressure pump 19 and leading to a non-return inlet valve 21 of cylinder 3. A pressure relief valve 30 diverts high pressure fluid through a line 35 to an oil tank 18 and actuates a switch 37 to stop the motor 1. To avoid stopping the pump at high pressures valve 8 is closed and a valve 33 opened whereby pump delivery is diverted past a non- return valve 14 and a pressure-retaining valve 16 to tank 18 and line 10 is connected by valve 33 to a record inlet valve 34. Low pressure pump 19 not only feeds pump cylinder 3 but may extend piston 13 rapidly when under no load when low pressure fluid is directed by a valve 42 through a line 43 and a coupling 44 connected to line 10. To quickly retract piston 13 under no load, low pressure fluid is directed through valve 40 and lines 39, 47.