Patent ID: 6206353
Filing Date: 2001-03-27
Classification: B25B

Abstract:
A clamping device comprising a clamping rod configured to be displaced by pneumatic, hydraulic or electrical energy, a clamping arm mounted so as to be pivotable between a clamping position and a ready position, a rigid lever rigidly connected through a pivot shaft to the clamping arm, a rigid bracket rotatably coupled to the lever in a first coupling joint and to an end of the clamping rod in a second coupling joint, the rigid bracket having a length between the first and second coupling joints which is greater than a distance between the first coupling joint and a longitudinal axis of the clamping rod in the ready position, at least one roller for supporting the second coupling joint, the at least one roller being configured to roll on a forced guide means, the forced guide means having a length portion corresponding to a pivoting angle of the clamping arm between the ready position and the clamping position, wherein the length portion extends in a straight line parallel to the longitudinal axis of the clamping rod in the ready position, the forced guide means further having an end portion, the end portion being concave toward the first coupling joint in a dead center position thereof, wherein the concave end portion is positioned relative to a plane, extending through the first coupling joint when the first coupling joint is in the dead center position thereof and perpendicularly of the longitudinal axis of the clamping rod in the ready position, such that the concave end portion begins at a side of the plane facing the ready position and ends in an upper end at a side of the plane facing away from the ready position, wherein the concave end portion has a radius corresponding to the distance between the first and second coupling joints plus the radius of the roller, and wherein the at least one roller is configured to pass through the plane in a direction toward the upper end and to provide a self-locking action when positioned at the upper end.