| 摘要 |
A pressure operated valve actuator is disclosed. In the preferred embodiment, fluid under pressure is introduced at either end to actuate the device. The device includes a cylindrical body having top and bottom end caps which close the body. On the interior, there is a central shaft which is rotated. A piston traverses the internal cavity of the housing, the piston being urged by pressure introduced above or below the piston. The piston is prevented from rotation by specified guide posts. As the piston traverses the length of the apparatus, engagement is made by the piston and the central shaft with helical grooves receiving a ball bearing. This achieves rotational motion from the linear movement of the piston to the central shaft. This rotational movement is imparted to the shaft, and, dependent on scale factors, a specified amount of rotation, such as one-quarter turn, can be obtained. The apparatus functions bidirectionally.
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