| 摘要 |
<p>A soil aerating apparatus comprising a towing vehicle, a soil aerating device comprising a drum, tines extending radially from the drum, and a frame for supporting the drum for rotation about a horizontal axis. The frame includes a forward end with a draw arm, and the forward end is pivotally attached to the towing vehicle so that the frame is raised and lowered by moving the draw arm. The apparatus also includes a mechanism for moving the draw arm comprising a hydraulic cylinder including a piston rod and connected between the draw arm and the towing vehicle, and a valve operably connected to the cylinder for extending and retracting said piston rod. The valve includes a valve member movable between a position wherein the valve extends the piston rod, a position wherein the valve holds the piston rod in a fixed position, a position wherein the valve retracts the piston rod, and a position wherein the valve permits the piston rod to extend or retract in response to movement of the draw arm. The apparatus also includes a mechanism for moving the valve member. The mechansim includes a lever pivotally connected to the valve member and pivotally mounted for movement between four positions corresponding to the valve member positions. The mechanism for moving the draw arm also includes a mechanism for releasably securing the lever in the position where the piston rod is free to move.</p> |
