There are instances wherein air or hydraulic cylinders of considerable length are used to control various mechanisms. In some of these instances while rapid extension or retraction of a fluid motor is desired retraction or extension of the same fluid motor in the opposite direction at a slower rate may be desired. Accordingly, various different forms of multi-speed control valves heretofore have been operatively associated with fluid cylinders. However, many of these multi-speed control valves are extremely complex in nature and "over engineered" in order to accomplish a relatively simple task. Accordingly, a need exists for a more simplified and reliable multi-speed control valve operative to allow extension and retraction of associated fluid cylinders at different speeds. Examples of various forms of previously known multi-speed control valves as well as other similar structures are disclosed in U.S. Pat. Nos. 2,749,937, 3,117,591, 3,122,162, 3,460,569, 3,561,471 and 4,147,179.
USPTO Backgrounds
USPTO Backgrounds