| 摘要 |
A double-acting, pressure medium manoeuvred driving device for generating a repetitive, reciprocating movement and consisting of a cylinder 11 with a piston 18 movable therein, the latter having a hollow shape with a valve means 30 extending through it in the form of an elongate hollow body, closed at both ends but provided with openings 37, 34, 33. The valve means cooperate with a valve housing 22 contained in one end of the cylinder, and may be carried along in the movement of the cylinder in such a way that the pressure medium is introduced into the cylinder through said valve body when the piston makes its returning stroke, while the return medium leaves the cylinder through the valve body while the piston makes its forward stroke. In order to generate a movement which is fast in one direction and slow in the other direction, the valve body has an elongate slit 37 whereby means may be present in the cylinder for choking the flow of pressure medium. <IMAGE> |
