| 摘要 |
<p>A towed implement 10 is mounted on a tractor three-point hitch 14 by means of a hitch structure 12 which is immobilised against lateral movement whether the hitch is lifted or lowered. The implement comprises a transfer beam or frame 18 which is attached to the hitch structure 12 by four parallel links 17, 72 arranged in two laterally spaced pairs with the links of each pair spaced vertically. A hydraulic actuator moves the beam 18 laterally while the links keep the beam perpendicular to the direction of travel. Ground followers 150 follow an existing furrow and operate switches controlling the hydraulic actuator to maintain the implement correctly positioned relative to crop rows being cultivated. The actuator holds the position of the beam 18 so that positional errors do not arise even on sideways sloping ground. In order to establish correct conditions at the start of each pass, when the three-point hitch 14 lifts the implement, the arms of the followers 150 drop into V-shaped recesses which reposition the followers centrally. Moreover, a switch actuated by the lift mechanism disables the control by way of the followers 150 and enables a centering switch which senses the position of the hydraulic actuator and returns the beam 18 to a centered position.</p> |
