An extremely fast-acting valve operator including a piston slidable in a pneumatic cylinder and connected by means of a chain and sprocket with the rotatable actuating shaft of a valve so that rapid movement of the piston imparts a rapid rotation to the shaft to open the valve. The piston is subjected to a high pressure gas but is initially restrained against motion within its cylinder by means of a quick release mechanism whereby release of said mechanism results in the piston undergoing immediate and rapid movement responsive to the expanding gas to thereby rapidly open the valve. This abstract is not to be construed in any way to define or limit the invention set forth below.
