Hydraulically controlled scarifier

Claim 1

A SCARIFIER EMBODIED IN AN EARTH SCRAPING TOOL DRAWN BY A POWERED TRACTOR, SAID SCARIFIER COMPRISING: A DRAFT BEAM ADAPTED TO BE SUPPORTED RIGIDLY AT ITS OPPOSITE THEREON SAID TOOL; A SCARIFIER BAR HAVING TEETH ATTACHED THERETO, SAID BAR BEING ARRANGED PARALLEL WITH AND GENERALLY REARWARDLY FROM SAID BEAM; PIVOTALLY CONNECTED LUGS FIXED ON SAID BEAM AND SAID BAR AT SYMMETRICALLY SPACED POINTS THEREON FOR PIVOTALLY MOUNTING SAID BAR AND SAID BEAM TRANSVERSE AXIS DISPOSED BETWEEN SAID BAR AND SAID BEAM WHEREBY SAID BAR IS SWINGABLE ABOUT SAID AXIS BETWEEN A DOWNWARD TEETH EXTENDING POSITION AND AN UPWARD TEETH RETRACTING POSITION; STRIKER PLATE MEANS PROVIDED UPON A FORWARD LOWER EDGE OF SAID BEAM; HOOK MEANS DISPOSED SYMMETRICALLY WITH THE CENTRAL VERTICAL FORE-AND-AFT AXIAL PLANE OF SAID BEAM AND PIVOTALLY MOUNTED ON SAID BAR ON A TRANSVERSE AXIS, SAID HOOK MEANS BEING ADAPTED TO HOOK UPWARDLY OVER SAID STRIKER PLATE MEANS AFTER SAID BAR HAS BEEN SWUNG INTO ITS DOWNWARD POSITION; A STOP MOUNTED ON SAID BAR; MEANS FOR YIELDABLY HOLDING SAID HOOK MEANS IN NON-LOCKING POSITION AND IN AN ENGGEMENT WITH SAID STOP; AND REVERSIBLE HYDRAULICALLY OPERABLE POWER MEANS MOUNTED ON SAID BEAM AND BEING CONNECTED BY A RIGID LINK TO SAID HOOK MEANS, SAID POWER MEANS, WHEN POSITIVELY POWER ACTUATED, HOLDING SAD BAR, THROUGH SAID HOOK MEANS, IN UPWARD POSITION, SAID POWER MEANS, WHEN RE-