Hammer drill

US3955628A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Dieter Grozinger
• Heribert Schramm · Stuttgart, DE
• Steffen Wunsch · Waldenbuch, DE
• Erich Hubert Vogel · Oakland, US

Key dates

• Filing date: Apr 18, 1974
• Grant date: May 11, 1976
• Expiry date: Apr 18, 1994

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B25D2216/0046
• WIPO field: Machine tools
• WIPO sector: Mechanical engineering

Abstract

A driven output shaft is mounted in a housing and has freedom of limited axial displacement between a first and a second position. A biasing spring permanently biases the output shaft to the first position. An impact member surrounds the output shaft and has a plurality of angularly spaced first axial projections which interdigitate with angularly spaced second axial projections provided on a disk member axially fixed on and turnably surrounding the output shaft. A retaining arrangement is provided in the housing and is engageable with the disk member to prevent rotation of the same when an axial force is exerted upon the output shaft counter to the action of the biasing spring, causing axial displacement of the output shaft to the second position thereof, and engagement of the disk member with the retaining arrangement.