Impact ripper and control

Abstract

Impact rippers are useful in fracturing rocks, concrete, etc. which cannot be fractured by ripping alone. Operating the impactor of the impact ripper without sufficient loading applied to the ripper tip is detrimental to the life of the impact ripper. The subject control system includes a pilot operated selector valve which blocks pressurized fluid from the impactor in the absence of pilot fluid thereto and is shifted by pressurized pilot fluid to a position to direct pressurized fluid to the impactor. A pressure switch is rendered conductive when the fluid pressure generated in a hydraulic cylinder exceeds a predetermined value due to loading on the ripper tip. This actuates a solenoid valve to direct pressurized pilot fluid to the selector valve. Thus the impactor is activated only when the loading on the ripper tip is above a preselected threshold and is automatically deactivated when the loading on the ripper tip drops below the preselected threshold.

Dependencies are inferred from the claim text.