| 摘要 |
<p>TRACTOR-IMPLEMENT CONTROL SYSTEM A mobile agricultural machine pulled by a tractor has first and second hydraulically actuated functional units powered through a single pair of outlets of a hydraulic system on the tractor. A spool-type direction control valve mounted on the machine has its inlet side connected to the outlets of the tractor hydraulic system and outlets connected to the respective hydraulic actuators. The valve spool is selectively positioned by means of a cam to direct oil to actuate either the first or second functional units. The cam is rotated by a bell crank through a sprag clutch so that the cam is driven in one direction only. The throw of the bell crank is limited by a stop and it is provided with a spring return so that an operator on the tractor may, by successive pulls on a single control rope attached to the bell crank, progressively index the cam and hence selectively actuate either the first or second functional units on the machine.</p> |
