Air shutoff swing gate valve

Abstract

An air shutoff valve includes a passage for supplying air, a swing gate, a shaft attached to a reset handle, and a spring to urge the gate toward its closed position. A trigger assembly secures the shaft and gate in the open position and includes an actuator, a cam, and a rocker arm. A cam surface of the arm has a notch to receive a sear point of the cam. Movement of the handle against the spring causes the cam contact surface of the cam to follow the cam surface to cause the arm to rotate such that the sear point is received in the notch. Actuating the actuator causes the arm to pivot away from the cam such that the sear point is released from the notch, wherein the spring causes the shaft to move the gate to its closed position.

What is claimed is: 
     
         1 . An air shutoff swing gate valve, comprising:
 (a) a valve body having an air passage therein, the air passage for supplying air;   (b) a valve swing gate, pivotable on a swing arm that is pivotally disposed adjacent to the valve body, the swing gate pivotable within the air passage from an open position wherein the swing gate is positioned adjacent to the air passage to provide for free flow of air through the air passage, to a closed position wherein the swing gate is positioned within the air passage to substantially close off the air passage;   (c) an actuation assembly comprising an actuation housing and a trigger assembly, the actuation housing disposed on the valve body;   (d) a pivotable shaft having a longitudinal axis, the shaft extending from the actuation assembly at least to the swing arm, the swing arm disposed on the shaft such that rotation of the shaft about its longitudinal axis causes rotation of the swing arm, to move the swing gate between its open and closed positions;   (e) a reset handle disposed on the shaft, such that rotation of the reset handle to rotate the shaft causes the swing gate to move from its closed position to its open position;   (f) a spring to rotationally bias the shaft about its longitudinal axis to urge the swing gate toward its closed position;   (g) the trigger assembly for securing the shaft such that the swing gate is held in its open position and for triggering the shaft to rotate due to biasing from the spring to cause the swing gate to move from the open position to the closed position, the trigger assembly comprising:
 (i) an actuator disposed at a first end of the actuation housing, the actuator having an actuator shaft; 
 (ii) a pivotable cam disposed in the actuation housing adjacent to a second end of the actuation housing and disposed on the pivotable shaft such that rotation of the pivotable cam causes rotation of the pivotable shaft, the cam having a notch and a cam surface; and 
 (iii) a trigger rocker arm disposed in the actuation housing, the trigger rocker arm having a first end pivotally attached to actuator shaft of the actuator, a central portion pivotally attached to the actuation housing between the pivotable cam and the actuator, and a sear point and a cam contact surface at a second end of the trigger rocker arm, the sear point for receipt in the notch of the cam, the cam surface of the cam for contacting the cam contact surface of the trigger rocker arm such that rotational movement of the reset handle against the bias of the spring causes the cam contact surface of the trigger rocker arm to follow the cam surface of the cam to cause the rocker arm to rotate about its central portion to a position until the sear point is received in the notch; and 
   (h) wherein actuation of the actuator to cause linear movement of the actuator shaft causes the first end of the rocker arm to move such that the rocker arm pivots about the central portion of the rocker arm to cause the second end of the trigger rocker arm to rotate away from the notch such that the sear point of the trigger rocker arm is released from notch of the cam, wherein the spring causes the shaft to rotate about its longitudinal axis to move the swing gate to its closed position.   
     
     
         2 . The air shutoff swing gate valve of  claim 1 , wherein the actuator is of a type selected from the group consisting of mechanical, electro-mechanical, hydraulic, pneumatic, and piezo. 
     
     
         3 . The air shutoff swing gate valve of  claim 1 , wherein the actuator is a solenoid. 
     
     
         4 . The air shutoff swing gate valve of  claim 1 , further comprising a switch connected to a display that indicates when the swing gate is in its open and closed positions. 
     
     
         5 . The air shutoff swing gate valve of  claim 4 , wherein the switch is adjacent to the cam and wherein rotation of the cam activates and deactivates the switch. 
     
     
         6 . The air shutoff swing gate valve of  claim 1 , further including a manual override device to provide for manual tripping of the swing gate, comprising an override device shaft slidably disposed in an aperture in the actuator housing adjacent at least to the actuator, the override device shaft being coaxial with the actuator shaft, the override device shaft having a first end and a second end, the first end disposed outside the actuator housing and having a handle for manual movement of the override device shaft through the aperture, the second end disposed on the actuator shaft, such that manual movement of the override device shaft causes substantially identical movement of the rocker arm as the movement caused by the actuator shaft. 
     
     
         7 . The air shutoff swing gate valve of  claim 1 , further including a manual override device to provide for manual tripping of the swing gate, comprising an override device shaft slidably disposed in an aperture in the actuator housing adjacent to the actuator, the override device shaft being substantially parallel to an axis of movement of the actuator shaft, the override device shaft having a first end and a second end, the first end disposed outside the actuator housing and having a handle for manual movement of the override device shaft through the aperture, the second end disposed adjacent to the first end of the rocker arm, such that manual movement of the override device shaft causes substantially identical movement of the rocker arm as the movement caused by the actuator shaft. 
     
     
         8 . In an air shutoff swing gate valve having a valve swing gate pivotable from an open position to provide for free flow of air through the air passage to a closed position to substantially close off the air passage, an actuation assembly, a pivotable shaft extending from the actuation assembly to the swing arm, a reset handle to rotate the shaft to cause the swing gate to move from its closed position to its open position, a spring to rotationally bias the shaft about its longitudinal axis to urge the swing gate toward its closed position, a trigger assembly for securing the shaft such that the swing gate is held in its open position and for triggering the shaft to rotate due to biasing from the spring to cause the swing gate to move from the open position to the closed position, the trigger assembly comprising:
 (a) an actuator having an actuator shaft;   (b) a pivotable cam disposed on the pivotable shaft such that rotation of the pivotable cam causes rotation of the pivotable shaft, the cam having a notch and a cam surface; and   (c) a trigger rocker arm having a first end pivotally attached to actuator shaft of the actuator, a central portion free to pivot disposed between the pivotable cam and the actuator, and a sear point and a cam contact surface at a second end of the trigger rocker arm, the sear point for receipt in the notch of the cam, the cam surface of the cam for contacting the cam contact surface of the trigger rocker arm such that rotational movement of the reset handle against the bias of the spring causes the cam contact surface of the trigger rocker arm to follow the cam surface of the cam to cause the rocker arm to rotate about its central portion to a position until the sear point is received in the notch; and   wherein actuation of the actuator to cause linear movement of the actuator shaft causes the first end of the rocker arm to move such that the rocker arm pivots about the central portion of the rocker arm to cause the second end of the trigger rocker arm to rotate away from the notch such that the sear point of the trigger rocker arm is released from notch of the cam, wherein the spring causes the shaft to rotate about its longitudinal axis to move the swing gate to its closed position.   
     
     
         9 . The trigger assembly of  claim 8 , further including a manual override device to provide for manual tripping of the swing gate, comprising a slidably disposed override device shaft adjacent to the actuator, the override device shaft being coaxial with the actuator shaft, the override device shaft having a first end having a handle for manual movement of the override device shaft and a second end disposed on the actuator shaft, such that manual movement of the override device shaft causes substantially identical movement of the rocker arm as the movement caused by the actuator shaft. 
     
     
         10 . The trigger assembly of  claim 8 , further including a manual override device to provide for manual tripping of the swing gate, comprising a slidably disposed override device adjacent to the actuator, the override device shaft being substantially parallel to an axis of movement of an actuator shaft of the actuator, the override device shaft having a handle for manual movement of the override device shaft, the second end disposed adjacent to the first end of the rocker arm, such that manual movement of the override device shaft causes substantially identical movement of the rocker arm as the movement caused by the actuator shaft.