Ground-working apparatus

Claim 1

IN A SELF-ADJUSTING GROUND-WORKING APPARATUS ADAPTED TO BE ATTACHED TO A SUPPORT MEMBER, THE COMBINATION COMPRISING A FRAME MEANS, A THRUST BAR MEANS FIXED TO AND EXTENDING BELOW SAID FRAME MEANS, ARM MEANS, MEANS FOR COUPLING SAID ARM MEANS TO THE MEMBER FOR VERTICAL PIVOTAL MOVEMENT WITH RESPECT THERETO; MEANS FOR PIVOTALLY COUPLING SAID ARM MEANS TO SAID FRAME MEANS FOR VERTICAL PIVOTAL MOVEMENT WITH RESPECT THERETO; SAID THRUST BAR MEANS BEING DISPOSED BETWEEN THE MEMBER AND THE PIVOTAL CONNECTION OF SAID ARM MEANS WITH SAID FRAME MEANS WHEREBY SAID FRAME MEANS AND SAID THRUST BAR MEANS ARE RECIPROCAL WITH RESPECT TO THE MEMBER; A GROUND-ENGAGING WHEEL; AND SUPPORT MEANS PIVOTALLY COUPLED TO SAID THRUST BAR MEANS AND SUPPORTING SAID GROUNDENGAGING WHEEL FORWARD OF THE THRUST BAR WHEREBY SAID SUPPORT MEANS PIVOTS ABOUT SAID THRUST BAR MEANS, AND MOVES VERTICALLY WITH SAID FRAME MEANS IN RESPONSE TO MOVEMENT OF SAID GROUND-ENGAGING WHEEL OVER SURFACE IRREGULARITIES, SAID SUPPORT MEANS HAVING MEANS ADAPTED TO SUPPORT A GROUND-CUTTING TOOL FOR MOVEMENT THEREWITH IN RESPONSE TO MOVEMENT OF SAID GROUND-ENGAGING WHEEL AND MEANS COOPERATING BETWEEN SAID FRAME AND SAID SUPPORT MEANS FOR URGING SAID SUPPORT MEANS TO PIVOT ABOUT SAID THRUST BAR MEANS IN A DIRECTION TO MAINTAIN SAID GROUND ENGAGING WHEEL IN ENGAGEMENT WITH A SURFACE BEING TRAVERSED.