| 摘要 |
<p>A valve including a valve member having two different stable positions, and a valve operator for shifting the valve member between its two stable positions and holding the valve member in those positions. The valve operator includes a shuttle moveable between two extreme positions corresponding to the two stable positions, respectively, of the valve member. A first spring urges the shuttle toward one of its extreme positions and a second spring, stronger than the first spring, urges the shuttle toward the other of its extreme positions, these movements of the shuttle being transmitted to the valve member. A device, such as an electric solenoid, selectively renders the second spring ineffective with respect to the shuttle, so that when the second spring is ineffective the first spring causes the valve member to assume one of its stable positions, and when the second spring is not ineffective, the second spring causes the valve member to assume the other of its stable positions.</p> |
