| 摘要 |
<p>HYDRAULIC DRAFT CONTROL The lower draft link of a tractor three-point hitch includes a sensor to sense draft loads imposed on the draft link by an earth-working implement. Variations in the draft load cause variations in the pressure of the fluid in the sensor from a preselected pressure. A pilot-operated, load control valve is connected to the sensor and is shiftable in response to pressure above and below the preselected pressure to actuate a control mechanism. The control mechanism actuates a direction control valve for directing fluid to and from a hydraulic lift cylinder for respectively raising and lowering the draft link to adjust the implement so as to maintain the preselected pressure and thus maintain the desired draft load.</p> |
