| 摘要 |
1,224,117. Hydraulic reciprocating pumps. CHALLENGE-COOK BROS Inc. May 2, 1969 [May 3, 1968], No.22644/69. Heading F1A. [Also in Division F2] A pump comprises an engine 16 alternatively driving rams 18, 20 to force concrete through an outlet 12 under the control of valves 30, 32 the concrete passing to the rams from a hopper 10 past valves 26 and 28. Each valve 26, 28, 30, 32 comprises a closure member 52, reciprocated in a cylinder 48 by a hydraulic motor 54, and having a tapering projection 56 to press a seal 58 into sealing engagement with the cylinder wall. |
