Clamping tool for non-positive and high-precision clamping of workpieces

US5197720A · kind A · utility

Assignee

• Daimler-Benz AG · DE

Inventors

• Rainer Renz · Stuttgart, DE
• Johann Kramer · Leonberg, DE

Key dates

• Filing date: Mar 22, 1990
• Grant date: Mar 30, 1993
• Expiry date: Mar 22, 2010

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B23B2228/16
• WIPO field: Machine tools
• WIPO sector: Mechanical engineering

Abstract

The invention concerns a clamping tool for non-positive and high-precision clamping of workpieces by means of an expansion element, which is held inside the clamping tool and, in the unclamped state, is matched to the workpiece with little play but movably, and to which force may be applied radially over a large area. When force is applied, the expansion element expands reversibly, and bears non-positively against the workpiece, and holds it in place with high rotational accuracy and high clamping force. In order to be able to permit a high expansion rate of the expansion element in conjunction with a closed configuration of the latter, the invention proposes for the expansion element a so-called shape memory alloy, which is operated in the austenitic state with reversible stress-inducible possibility of change of the microstructure into the martensitic state. For this reason, the workpiece can also be matched to the clamping tools with substantially coarser tolerances, and this has a favorable influence on the production costs.