| 摘要 |
In a forage harvester with a height adjustable cutting head having ground engaging means in the form of slide shoes, one of these or another machine member, caused to be deformed by the pressure of the slide shoe against the ground, mounts a strain gauge (21) which, in response to variation of the engagement pressure, applies an electric signal actuating via an amplifier (42) one or the other of two magnet valves (43 and 44), which controls the supply and discharge, respectively, of oil to and from a hydraulic cylinder (16), which thereby raises and lowers, respectively, the cutting head until the desired pressure between the slide shoe and the ground has been re-established. Thus, the cutting head is kept at a substantially constant height above the ground irrespective of irregularities in the surface of the ground, so that also the stubble height is kept substantially constant. |
