Motor-driven hand-held percussion tool

US4476941A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Manfred Buck · Jeffery Road, DE
• Frank Müller · Birkenfeld, DE
• Karl Wanner · Echterdingen, DE

Key dates

• Filing date: Sep 27, 1982
• Grant date: Oct 16, 1984
• Expiry date: Sep 27, 2002

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B25D2217/0065
• WIPO field: Machine tools
• WIPO sector: Mechanical engineering

Abstract

A hand-held motor-driven percussion tool comprises a piston driven over an air cushion and acting over an axially movable anvil on the inner end of a tool axially movable in a tool receiver provided at one end of a tool housing. The anvil has an annular collar located in the cavity of an impact body which is movable in the direction of the impact of the piston against a cushioning ring. The impact body has an abutment face adapted to be engaged by a collar of the anvil when the latter is driven by the piston. A face of the impact body facing away from the cushioning ring is directed toward a part fixedly connected with the tool housing. The mass of the impact body is for instance 10% greater than that of the anvil. If the tool during operation is withdrawn from a workpiece, then the flange of the anvil impinges upon the abutment face of the impact body and accelerates the latter towards the cushioning ring. The anvil reaches in a region adjacent the impinging location a rest position, so that the piston will not engage the anvil any longer, and further striking of the percussion tool will cease.