Method and apparatus for protecting a fluid-operated percussion device against no-load strokes

US6672403B2 · kind B2 · utility

Assignee

• Krupp Berco Bautechnik GmbH · DE

Inventors

• Torsten Ahr · Essen, DE
• Thomas Deimel · Bad Hersfeld, DE
• Stefan Lohmann · Mülheim, DE

Key dates

• Filing date: Apr 30, 2002
• Grant date: Jan 6, 2004
• Expiry date: Apr 30, 2022

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B25D9/265
• WIPO field: Machine tools
• WIPO sector: Mechanical engineering

Abstract

Depending on the working and application conditions, it may be desirable to equip fluid-operated percussion devices with a mechanism that protects against no-load strokes, particularly in the interest of avoiding undesired stress. In the present case, this protection mechanism is configured such that the control unit that influences the movements of the percussion piston is blocked by a safety element in the form of a multiple-position valve, and the percussion device is halted if the percussion piston overshoots the extended position occurring in normal operation by a defined distance, thereby assuming a no-load-stroke position. The safety element (21) that acts on the control unit (5) of the percussion device (1) is automatically controlled, notably such that it is not switched to be active until some time after the startup of the percussion device (1) acted on by the working pressure. The percussion device (1) can therefore start up without being influenced by the safety element (21).