Stretching and fastening device for blankets and the like on printing

Abstract

A lock-up mechanism for a blanket cylinder in a printing press, the blanket having at each end a straight reinforcing bar formed of metal stock bent into 'U' cross section. An arm recessed in the cylinder provides a U-shaped receptacle for receiving the reinforcing bar; the receptacle has first and second supporting surfaces offset from one another for engaging the opposite faces of the bar. A hook is provided on the arm adjacent the second supporting surface for hooking the near edge of the bar, the projection of the hook beyond such supporting surface approximating the thickness of the bar material. The U-shaped receptacle is of such a size as to permit insertion of the bar in a temporarily angled position to clear the hook. The plane of support of the bar in the receptacle is so related to the plane of applicatiom of blanket tension that when the blanket is drawn taut, torque is applied to the bar tending to seat it securely on the supporting surfaces thereby insuring that the bar is engaged and held captive by the hook until the tension is intentionally released. In the preferred form of the invention the arm is pivoted to the cylinder for swinging movement and a manually operated screw is provided for holding the arm in a rocked position thereby to adjustably tension the blanket.