DOUBLE-ACTING TELESCOPIC HYDRAULIC CYLINDER Russian patent published in 2000 - IPC

FIELD: materials handling machinery; power positive-displacement hydraulic mechanisms. SUBSTANCE: hydraulic cylinder has coaxial set of piston stages, each with rod spaces, and piston space. One of hydraulic cylinder stages has double-side rod whose ends differ in section areas. Working areas of piston sides also differ in size. Piston space of hydraulic cylinder is formed by piston spaces of each stage installed for getting into opposite phases in extreme positions of hydraulic cylinder. Unlike spaces of hydraulic cylinder are hydraulically connected in pairs to form united spaces so that at maximum volumes of piston spaces united spaces of hydraulic cylinder are connected with pressure head and at maximum volume of piston space of one of stages, united space formed by corresponding space is connected with pressure head, and other united space is connected with drain. Cylinder of double-side rod stage can be made in form of rod-and-step sleeve mated with ends of different diameter rod for axial displacement. Its mated surfaces can be made in form of different diameter cylinders. Invention makes it possible to dispense with flexible lines for delivering working liquid owing to provision of hydraulic coupling of hydraulic cylinder spaces ensuring delivery of working liquid to any stationary part of hydraulic cylinder with guaranteed successive and independent action of hydraulic cylinder stages. EFFECT: enhanced operation reliability. 4 cl, 4 dwg