Dual piston actuator

摘要

A pair of axially aligned and nested pistons are mounted in a pressure sealed arrangement within the bore of a pressure housing. A primary piston is moved in response to increasing pressure to provide an actuating output force while a secondary piston simultaneously moves to overcome a reverse bias on it by a tension spring and adds to the actuating force by engaging the primary piston only when the pressure exceeds a specific higher threshold. The primary and secondary pistons thereafter operate in conjunction under the influence of high pressure to provide the output actuating force.