Patent ID: 7150086

Claim:
A tool that connects plates or plate pieces placed on top of each other, or plates with connecting points comprising: a matrix having a working opening, a punch, powered in the direction of the working opening, a matrix base plate positioned across from the punch, at least three matrix sheathing pieces arranged radially around the working opening, said sheathing pieces adapted to move radially outward during a clinching procedure, said sheathing pieces being restricted in movement by displaced work pieces, and said sheathing pieces are mounted in the matrix base plate, said matrix base plate comprises: bar-shaped springs operating radially inward of sides that engage the sheathing pieces, at a first end the springs engage the sheathing pieces, at a second end the springs are one-piece connected with each other through a connecting section in a crank for each spring in the direction of the sheathing pieces, in a transition area between the connecting section and the springs said connecting section located at a dividing plane of the matrix which runs transverse to a driving direction, said sheathing pieces are mostly arranged axially symmetric around a centerline of the matrix and the connecting sections take the form of a cross, ring-shaped or star-shaped, wherein during the clinching procedure, the punch does not cut through the plate.