US Patent 7234679 Gate valve

A gate valve has a transfer chamber-side valve element and a process chamber-side valve element connected to a single shaft. A rotary latch pivotably supported on an inner surface of one of the valve element with the rotary latch having a latch surface at a forward end thereof, wherein when a rotational force is applied to the rotary latch in one direction, the latch surface is pressed against a joint surface of the single shaft, whereby the valve element is latched to said single shaft, and when a rotational force is applied to the rotary latch in the opposite direction, the latch surface is separated from the joint surface of the single shaft to unlatch the valve element.