| 摘要 |
A hydraulic power press has a box-shaped frame whose top defines a work space with a bedplate received in that frame, the frame bottom being rigid with a hydraulic cylinder whose piston carries the bedplate. Frame and cylinder are interconnected by columns guiding the bedplate within the frame. The piston has a downwardly projecting rod terminating in an annular flange forming a shoulder which coacts with a set of plungers within the cylinder adapted to be pressurized for moving the piston with the bedplate downwardly. The upper limit of the working stroke of the piston is defined by a rotatable ring threadedly engaging the lower end of the cylinder to form an adjustable abutment for the piston flange. The lower limit of the return stroke is determined by a stud, projecting downwardly from the piston, which on descending coacts with the body of a slide valve whose mounting is fixedly suspended from the cylinder and which, besides cutting off the flow of pressure fluid to the downwardly acting plungers, also cushions the descent of the piston. The stud is threadedly lodged in the piston and can be rotated by a bevel-gear transmission inside the bedplate and the piston for adjusting the lower end of the piston stroke.
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