Centrifugal clutch

US4819779A · kind A · utility

Assignee

• Andreas Stihl AG & Co. KG · DE

Inventors

• Hans Nickel · Cottenweiler, DE
• Michael Wissmann · Markgröningen, DE
• Horst Scholz · Warstein, DE

Key dates

• Filing date: Apr 8, 1987
• Grant date: Apr 11, 1989
• Expiry date: Apr 8, 2007

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B27B17/10
• WIPO field: Machine tools
• WIPO sector: Mechanical engineering

Abstract

A centrifugal clutch for use especially in a motor-driven chain saw. The clutch includes a carrier which is provided for attachment to a drive shaft and on which radially moveable centrifugal weights are mounted. The weights can move radially outwardly under centrifugal force and counter to spring force and come into contact engagement with the drum which is the output end of the clutch. A restraining device is provided between each centrifugal weight 2 and carrier 1 so that the engagement of the clutch does not occur until after an elevated speed has been reached. Disengagement of the clutch occurs as in known clutches somewhat above the idling speed. The restraining device is configured so that it does not clear the outward path of the centrifugal weight until a certain minimum centrifugal force has been exceeded. This has the effect that the clutch engages suddenly at mid range speeds and can transmit a very high initial torque to the output tool driven through the clutch.