Patent ID: 11920696
Assignee: SMC CORPORATION
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F | IPC F

Claim 0:
1. A gate valve disposed between a first chamber and a second chamber adjacent to each other, the gate valve being usable for causing a first opening communicating with the first chamber and a second opening communicating with the second chamber to communicate with each other and for opening and closing the first opening and the second opening separately, the gate valve comprising:
a bonnet partitioning off an upper side and a lower side;
a valve shaft passing through the bonnet in a direction along an axis extending in an up-down direction, the valve shaft having a tip end portion disposed above the bonnet and a base end portion disposed below the bonnet;
a valve assembly formed by attaching a first valve plate and a second valve plate back to back to the tip end portion of the valve shaft; and
a valve drive mechanism connected to the base end portion of the valve shaft, the valve drive mechanism being configured to move the valve assembly by operation of the valve shaft, wherein
the valve drive mechanism includes an air cylinder including a first drive rod and a second drive rod capable of being driven separately, the air cylinder being fixedly provided to the bonnet, and a power transmission mechanism connecting the valve shaft and both the first drive rod and the second drive rod, the power transmission mechanism being configured to transmit driving force of the air cylinder to the valve shaft and is thus capable of moving the valve assembly in the direction along the axis and a thickness direction orthogonal to the axis to move the valve assembly to a first closed position for closing the first opening with the first valve plate, a second closed position for closing the second opening with the second valve plate, and a retracted position for causing the openings to communicate with each other,
the power transmission mechanism includes a first cam frame connected to the first drive rod to operate together with the first drive rod, a second cam frame connected to the second drive rod to operate together with the second drive rod, a lever member attached to the base end portion of the valve shaft, and a first opening and closing mechanism and a second opening and closing mechanism configured to separately cause the valve assembly to reciprocate in the thickness direction,
the first opening and closing mechanism includes a first cam groove provided in one of the first cam frame and the lever member, and a first cam roller provided on another of the first cam frame and the lever member, the first cam roller being slidably fitted into the first cam groove, and the second opening and closing mechanism includes a second cam groove provided in one of the second cam frame and the lever member, and a second cam roller provided on another of the second cam frame and the lever member, the second cam roller being slidably fitted into the second cam groove,
the first cam roller reciprocates together with reciprocation of the first drive rod so as to follow the first cam groove, thus causing the valve assembly to reciprocate between a position occupied by the retracted position and a position occupied by the first closed position in the thickness direction, and the second cam roller reciprocates together with reciprocation of the second drive rod so as to follow the second cam groove, thus causing the valve assembly to reciprocate between the position occupied by the retracted position and a position occupied by the second closed position in the thickness direction,
the gate valve has a width direction orthogonal to both the direction along the axis and the thickness direction, and
at the first opening and closing mechanism and the second opening and closing mechanism, the first and second cam frames are disposed on both sides of the lever member in the width direction and are provided on both the sides of the lever member so as to be adjacent to each other in the thickness direction.