Pressurized fluid actuation system for amplifying operator input force in a surgical instrument

摘要

A pressurized fluid actuation system as provided for a surgical instrument. The system includes a double-acting fluid pressure actuator with an extension chamber and a retraction chamber separated by a piston for engaging a component of the instrument. An operating lever is pivotally mounted to the piston. The operating lever is also pivotally connected to a servo valve that has a valve spool. The valve is connected to a source of pressurized fluid and has first and second return ports for venting the fluid. The actuator extension and retraction chambers are connected with the valve for each communicating with the pressurized fluid source and with one of the return ports in response to the position of the valve spool. The system includes a feedback line communicating between the extension chamber and the valve to apply a force to the valve spool in one direction when the extension chamber is pressurized. The system also includes a sensing line communicating between the retraction chamber and the valve to apply a force to the valve spool in the opposite direction when the retraction chamber is pressurized.