Pneumatic impact tool

US4074777A · kind A · utility

Assignee

• Atlas Copco Aktiebolag · SE

Inventors

• Sture Andersson · Nacka, SE
• Heino Elmessaar · Lidingö, SE

Key dates

• Filing date: Mar 11, 1977
• Grant date: Feb 21, 1978
• Expiry date: Mar 11, 1997

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B25D9/14
• WIPO field: Machine tools
• WIPO sector: Mechanical engineering

Abstract

A pneumatic impact tool comprising a housing, an open ended cylinder inserted therein and a hammer piston reciprocably guided within the cylinder. In the forward end of the cylinder there is received the shank of a chisel onto which the hammer piston imparts impacts. The piston is a differential piston having its big end facing the chisel and forming around its rear, small diameter neck a rear annular, constantly pressurized chamber which continuously communicates with the pressure air inlet through a pulsator chamber. The forward cylinder chamber, enclosed between the chisel shank and the piston front area, is intermittently pressurized through an internal passage of the piston, which passage is periodically connected to the pressure air inlet by means of valve openings in the piston neck.