Hydraulic device for controlling a hydraulic-fluid flow

US6065386A · kind A · utility

Assignee

• Mannesmann Rexroth AG · DE

Inventors

• Winfried Rüb · Waldshut-Tiengen, DE
• Heinz Schulte · Paderborn, DE

Key dates

• Filing date: Jul 10, 1998
• Grant date: May 23, 2000
• Expiry date: Jul 10, 2018

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F15B2211/7052
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

The invention concerns a hydraulic device for controlling the hydraulic-fluid flow to and from a single-acting cylinder (3) on which a load (4) acts. Located between a pump (1) and the cylinder (3) is a controlled valve array (5) which, together with a controlled on-off valve (9) which in one position allows hydraulic fluid to pass back into the reservoir (2), controls the flow of hydraulic fluid to and from the cylinder (3). In order to be able to lift the piston slowly and at constant speed in the cylinder (3), independently of the load (4) acting on the piston, the invention calls for a throttle (6) and a non-return valve (7) to be connected in series, by-passing the valve array (5). A pressure regulator (10) maintains the pressure difference through the throttle (6) constant and feeds the fluid not required to maintain the pressure difference through the throttle (6) back to the reservoir (2). When the load (4) is lifted slowly, the valve array (5) is switched into a position in which the flow of hydraulic fluid to the cylinder (3) is blocked, and the cut-off valve (9) blocks the connection between the throttle (6) and the reservoir (2). The invention is particularly suitable f…