| 摘要 |
<p>A housing of the device has a first port for connection to a source of pressure fluid, a second port for connection to a reservoir, and internal passages which connect these ports. A pressure limiting valve is interposed in the passages for limiting the pressure that can prevail in the first port. A spring-loaded relief valve is also interposed in the passage intermediate the second port and the pressure limiting valve with which it is connected in series, and a switching valve is interposed in the passages connected in parallel with the pressure limiting valve and located intermediate the first port and the relief valve. The switching valve is thus controlled by the pressure which prevails ahead of the relief valve and the control device establishes communication between the ports in dependence upon the pressure which prevails in the first port.</p> |
