摘要 |
A fluid operated shift actuator (11) is provided, and is especially suited for use in an X-Y shift mechanism for a change-gear mechanical transmission. The shift actuator includes a piston rod (47), a piston member (87), and a pair of auxiliary pistons (93 and 95), to define fluid pressure chambers (91 and 92). After the piston member (87) and the piston rod (47) have been displaced from neutral in either direction, into a gear engagement position, pressurizing both fluid pressure chambers (91 and 92) will cause the actuator to return to the neutral position (gear disengagement) with substantially less force than that exerted when the actuator moved into the gear engagement position. |