A lock open device for use with a valve in a hydraulic fracturing system, which maintains the valve in an open position. The lock open device includes a plate with beveled edges and spring loaded ball bearings strategically disposed to contact the edges and interfere with axial movement of the plate. The plate couples to a gate member in the valve, so that the interference between the plate and the ball bearings maintains the valve in a designated open or closed position. The angle of the bevel regulates how much force is required to urge the plate past the ball bearings to thereby open/close the valve.