| 摘要 |
An apparatus selectively supplies a source of pressurized fluid to a load device and selectively exhausts pressurized fluid from the load device. The apparatus includes a first housing for defining a longitudinally extending aperture communicating through first, second, and third passages with spaced first, second and third external surface portions of the first housing. A valve spool is engageable within the first aperture for longitudinal movement between a first position communicating the second passage with the third passage and a second position communicating the first passage with the second passage. The valve spool is normally biased toward the first position. Modular port members are connectable to the first, second and third spaced external surface portions for connecting the first passage to a source of pressurized fluid, the second passage to the load device, and the third passage to an exhaust port. If desired, one or more parameters of operation of the valve spool can be monitored to determine if the valve spool has moved completely from the first position to the second position. Signals can be generated corresponding to the monitored parameters of operation, such as pressure and/or position. If desired, a speed control device is positionable on the second external surface portion interposed between the first housing and the modular port member for the second passage for controlling the speed of actuation of the load device.
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