US Patent 7422057 Whipstock with curved ramp

The whipstock face below the mounting lug is initially curved with a fairly long radius to protect the whipstock body initially. After moving down the minimally sloping curved face a transition to a greater angle is presented to increase the lateral forces on the window mill and to force the mill laterally to exit the tubular through the window. The transition after the curved portion is preferably to a flat inclined surface to the ramp bottom.