A hydraulic cylinder is provided. The hydraulic cylinder includes a casing with a longitudinal axis defined therethrough, a first fluid inlet defined in the casing, a second fluid inlet defined in the casing, a first fluid outlet defined in the casing, a second fluid outlet defined in the casing, a shaft extending along the longitudinal axis, a first switching valve mounted to the shaft, a second switching valve mounted to the shaft, and a piston mounted to the shaft between the first switching valve and the second switching valve, wherein the hydraulic cylinder is configured such that when a fluid is supplied to the first and second fluid inlets, the shaft, the first and second switching valves, and the piston oscillate back and forth along the longitudinal axis.