Workpiece-deforming tool and die for use in a punch press

A self-locking workpiece-deforming tool comprising:

• an elongated punch guide having an interior surface defining a chamber extending therethrough, the chamber having an upper portion and a lower portion;
• a punch body having an upper segment positioned at least partially within the upper portion of the chamber and a separate lower segment positioned at least partially within the lower portion of the chamber, the upper and lower segments being reciprocally axially moveable with respect to the guide between a raised position and a workpiece-deforming depressed position, the body being lockable in the depressed position and releasable to the raised position;
• a punch holder carried by the lower segment, the punch holder being reciprocally axially moveable with respect to the guide;
• a rotatable workpiece-deforming roller carried by the punch holder for movement between the raised position and the depressed position as the body and holder are reciprocated;
• positioning means for sustaining the body and rotatable workpiece-deforming roller in the depressed position without continuous pressure being exerted against the body by the ram, the positioning means locking the body and the rotatable workpiece-deforming roller in the depressed position upon a momentary strike by the ram and releasing the body in the rotatable workpiece-deforming roller to the raised position upon a subsequent momentary strike by the ram;
• and
• biasing means for transmitting force from the driver to the body and for urging the body and the rotatable workpiece-deforming roller into the raised position after the positioning means is released;
• the biasing means including a first spring operatively positioned between the upper segment and the lower segment for transmitting pressure therebetween and a second spring operatively positioned between the lower segment and the guide for urging the lower segment and the upper segment into the raised position after the locking means is released.