Dunn James Thomas,Leverick Graham Michael,Lyons Russell George,Shearer Bruce Robert
申请号：
US201615188468
公开号：
US9968033(B2)
申请日:
2016.06.21
申请国别(地区):
美国
年份:
2018
代理人:
Battison Adrian D.`Ade & Company Inc `Dupuis Ryan W.
摘要：
In a crop harvesting machine there is provided a pair of hydraulic float cylinders for a header relative to a vehicle, where a float pressure to the cylinders is directly controlled by an electronic control supplying a variable control signal to a PPRR valve arrangement to maintain the float pressure at a predetermined value. At the set pressure a predetermined lifting force is provided to the header. A position sensor is used to generate an indication of movement and/or acceleration. The electronic control is arranged, in response to changes in the sensor signal, to temporarily change the control signal to vary the lifting force and thus change the dynamic response of the hydraulic float cylinder. In order to reduce static friction so that the system can react quickly, an arrangement is provided for causing relative reciprocating movement in an alternating wave pattern between the piston and cylinder.
