Hydraulic tightening apparatus

US4997410A · kind A · utility

Assignee

• INA-WALZLAGER SCHAEFFLER KG · DE

Inventors

• Rudolf Polster · Baiersdorf, DE
• Werner Schmidt · Rengsdorf, DE

Key dates

• Filing date: Mar 14, 1990
• Grant date: Mar 5, 1991
• Expiry date: Mar 14, 2010

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16H2007/0891
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

A hydraulic actuating element particularly for a belt tightener having a pressure chamber arranged behind a piston guided in a cylinder, a reservoir separated from the pressure chamber by a check valve, the cylinder and the reservoir being completely oil filled, the outside of the reservoir being defined by a bellows, a leakage gap between the piston and the cylinder being open towards the reservoir and at its one side towards the pressure chamber, whereby a compression spring acts to urge apart the piston and cylinder, characterized in that the reservoir (13) surrounds the cylinder (2) and being limited by the bellows (12) at its outside, the bellows (12) being sealingly secured at one end to a base element (10) secured to the cylinder (2) and at its other end to a base element (11) secured to the piston (1), and that the leakage gap (3) at its other side (17) is externally shielded by the bellows (12) and open to the reservoir (13).