Expanding gate valve with position responsive interlock

摘要

A gate valve (10) has an expanding gate assembly (34) mounted in the valve chamber (14) for movement between open and closed positions. The gate assembly (34) includes a gate (44) connected to a valve stem (28) and a segment (52) is carried by the gate (44). The gate (44) and segment (52) each have wedging surfaces (46 and 54) which permit a wedging action to provide lateral expansion therebetween at the open and closed positions. A rocker arm (80) is pivotally mounted to a side (49) of the gate (44). The rocker arm (80) has a slot (102) with a bearing block (104) slidably received therein. A bearing pin (110) extends from a side (57) of the segment (52) and is journaled in the bearing block (104). A seat skirt (60) is contained within the valve chamber (14) and engages the rocker arm (80) so as to control the ability of the rocker arm (80) to pivot about the gate (44) thereby allowing the gate (44) and segment (52) to expand from each other at a preselected position in the travel of the gate assembly (34). A modification of the structure provides a recess (120) in the sides (49A and 57A) of the gate (44A) and segment (52A). A shoulder (126) protrudes from one side of the rocker arm (80A) and is received within the recess (120) whereby the rocker arm (80A) continues to function as before.