| 摘要 |
<p>A control circuit comprises a pressurized fluid source, a two-position directional control valve and an actuator, such as the pump of a hydrostatic transmission, connected to the fluid source and the control valve to be selectively actuated thereby. Relay valves are interconnected in the control circuit to sequentially (A) prevent communication of pressurized fluid from the source to the actuator upon activation of the source and when the control valve is maintained in its first position, (B) communicate pressurized fluid from the source to the actuator upon continued activation of the source and when the control valve is moved from its first position to a second position thereof, and (C) prevent communication of pressurized fluid from the source to the actuator when the source is deactivated and then reactivated with the control valve being maintained in its second position whereby the control valve must first be returned to its first position and then moved to its second position before pressurized fluid can be communicated to the actuator for actuation thereof.</p> |
