Actuator cylinder for lifting loads using pneumatic or hydraulic pressure has two concentric cylinders with pistons moving in opposite directions to extend piston rods

摘要

The inner cylinder (3) fits concentrically inside an outer cylinder (4). The inner cylinder contains a circular piston with a thin cylinder rod (1) extending through a sealed top plate (7). A first pressure connection (p1) in the piston rod admits fluid to move the piston and rod outwards. A second pressure connection (p2) in the top plate admits fluid to move the piston inwards. An annular piston with a thick hollow cylinder rod (2) extends through a slit in the bottom plate (5,6). A third pressure connection (p3) in the top plate admits fluid to push the annular piston outward and a fourth pressure connection (p4) at the bottom of the outer piston admits fluid to push the annular piston inward.