| 摘要 |
A hydraulically operated tool comprises two working members which are intended to be moved towards one another during a working stroke so as to work a workpiece located therebetween. At least one of the working members is driven by a piston-cylinder device. The tool may have the form of a wood splitter comprising a fixed splitting wedge (2) and a pressure plate (4) which is driven by a piston-cylinder device (6, 7) such as to feed wood pieces (3) towards the wedge. Hydraulic fluid under pressure is delivered to the piston-cylinder device (6, 7) via an adjustable valve (10) prior to each working stroke, such as to move an associated working member (4) towards the other member (2). A return spring (23) is provided for returning the working member when the hydraulic pressure is lowered. The piston (7) is provided with a normally closed channel (25) between the high pressure and the low pressure sides of the channel, and also with means for opening the channel as the piston approaches its end position in the cylinder. This means has the form of a mechanical actuator which functions to move an element which will normally close the channel when coming into contact with a part of the cylinder housing. |
