Changeover valve
First Claim
1. A changeover valve having first to third ports and providing fluid communication between either the first and second ports, or the first and third ports, comprises a housing into which the three ports open, a valve member movable between a first position in which the second port is closed and the third port is open and a second position in which the third port is closed and the second port is open, first resilient means acting continuously on the valve member to urge the valve member away from a balance point in its travel intermediate its first and second positions, and an actuating member movable between first and second positions and having associated therewith second resilient means to urge the actuating member away from balance point in its travel intermediate its first and second positions, the actuating member and valve member including cooperating abutments engageable to transmit motion of the actuating member to the valve member, and the valve further including pressure responsive means to urge the actuating member from is first position to its second position and from its second position to its first position, the arrangement being such that when the pressure responsive means urges the actuating member out of its first position and past its balance point, the second resilient means propels the actuating member toward its second position and during this motion the abutments engage and the valve member is carried out of its first position and past its balance point by the actuating member, whereupon the first resilient means propels the valve member to its second position, and when the pressure responsive means urges the actuating member out of its second position and past its balance point, the second resilient means propels the actuating member towards its first position and during this part of the motion the abutments engage and the valve member is carried out of its second position and past its balance point by the actuating member, whereupon first resilient means propels the valve member to its first position.
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Accused Products
Abstract
There is described a valve having three ports (3,4,5) one of which (3 or 4) is selectively closed by a bistable toggle-action valve member (6). An actuating member (17) driven by a pressure sensor (23) operates the valve member via cooperating abutments (18,19,20), the actuating member also having a bistable toggle-action and engaging the valve member as it approaches the end of its travel in either direction, to carry the valve member (6) over its balance point and thus effect the changeover of the valve.
4 Citations
6 Claims
- 1. A changeover valve having first to third ports and providing fluid communication between either the first and second ports, or the first and third ports, comprises a housing into which the three ports open, a valve member movable between a first position in which the second port is closed and the third port is open and a second position in which the third port is closed and the second port is open, first resilient means acting continuously on the valve member to urge the valve member away from a balance point in its travel intermediate its first and second positions, and an actuating member movable between first and second positions and having associated therewith second resilient means to urge the actuating member away from balance point in its travel intermediate its first and second positions, the actuating member and valve member including cooperating abutments engageable to transmit motion of the actuating member to the valve member, and the valve further including pressure responsive means to urge the actuating member from is first position to its second position and from its second position to its first position, the arrangement being such that when the pressure responsive means urges the actuating member out of its first position and past its balance point, the second resilient means propels the actuating member toward its second position and during this motion the abutments engage and the valve member is carried out of its first position and past its balance point by the actuating member, whereupon the first resilient means propels the valve member to its second position, and when the pressure responsive means urges the actuating member out of its second position and past its balance point, the second resilient means propels the actuating member towards its first position and during this part of the motion the abutments engage and the valve member is carried out of its second position and past its balance point by the actuating member, whereupon first resilient means propels the valve member to its first position.
Specification