Patent ID: 6474214
Filing Date: 2002-11-05
Classification: F01B,F15B

Abstract:
A three-position stop type swing actuator comprising:a casing having a first cylinder hole and a second cylinder hole therein, said first cylinder hole having a smaller diameter and a lager length in an axial direction of said casing than said second cylinder hole; a main piston disposed in said first cylinder hole to move in forward and backward directions in the axial direction; a sub piston having a large diameter portion configured to slide in an airtight manner within said second cylinder hole and a small diameter portion configured to slide in an airtight manner within said first cylinder hole, said sub piston being configured to move said main piston less than a full stroke of said main piston in the forward direction; an output shaft coaxially connected to said main piston in such a manner as to rotate around an axis of said output shaft; and a conversion and transmission mechanism configured to convert a forward and backward motion of said main piston into a rotating and swinging motion of said output shaft; wherein said casing provides a first pressure chamber on one end surface side of said main piston, a second pressure chamber between an opposite end surface of said main piston and the small diameter portion of said sub piston, and a third pressure chamber on a side of the large diameter portion of said sub piston.