Rake angle control for shears and the like

Abstract

The invention relates to hydraulically powered shears for metal sheets and plates and particularly to an improvement in the means for adjusting and controlling the rake angle or slope of the movable shear knife in such machines. In the present disclosure a rod member is pivoted at one end and normally is disposed along a line parallel to the direction of reciprocation of the ram of the shear. The upright member has a cable connection with a servo valve which controls the fluid circuitry of the shear to adjust the relative positions of the hydraulic motor means at opposite sides of the ram to change the inclination of the ram. When the rod member is in normal position the servo valve is blocked and the rake angle is maintained but when the rod member is adjusted angularly in either direction it operates through the cable means to adjust the servo valve in one direction or the other to change the relative vertical positions of the motor means. This operation of the servo valve changes the rake angle of the ram and its associated shear knife and at the same time restores the rod member to its normal position wherein the servo valve is in a blocking position and the adjusted angle is maintained.