| 摘要 |
<p>The hydraulic motor is for use in irrigation systems where the water-distributing appts. is moved across the field by coiling up its supply hoses. A cylinder (1) contains a piston (7) whose rod (8) is hollow for a certain distance, then solid. The bottom of the cylinder is closed by a sprung valve (29, 32) whose control rod (18) extends through the piston into the hollow piston rod. Water drives the piston (7) up the cylinder (1), the valve (32) then being closed. At a certain point, the moving piston picks up the valve control rod to open the valve and remove the piston drive.</p> |
