초록 ▼

The windrower or other harvester has a hydraulic lift circuit for its header that includes a pair of double-acting cylinders which operate in concert to raise the header and provide a solid, lower limit for downward swinging of the header. The two cylinders are connected to one another in a master-s

The windrower or other harvester has a hydraulic lift circuit for its header that includes a pair of double-acting cylinders which operate in concert to raise the header and provide a solid, lower limit for downward swinging of the header. The two cylinders are connected to one another in a master-slave relationship, and the slave cylinder has its return line normally blocked by a one-way check valve so that a body of fluid is trapped against the piston of the slave cylinder during field operations. This stabilizes the two cylinders to reduce header bounce.

대표청구항 ▼

[ We claim:] [1.] In a farm implement having a mobile frame to which a crop header may be attached, height control apparatus for the header comprising:a charging circuit containing hydraulic fluid under pressure;a lifting circuit including a master cylinder and a slave cylinder for exerting a pair o

[ We claim:] [1.] In a farm implement having a mobile frame to which a crop header may be attached, height control apparatus for the header comprising:a charging circuit containing hydraulic fluid under pressure;a lifting circuit including a master cylinder and a slave cylinder for exerting a pair of lifting forces at spaced locations on the header; anda control system between the charging circuit and the lifting circuit and selectively placeable in alternative lift, hold, or lower modes for either communicating the charging circuit with the lifting circuit in a manner to lift the header, blocking communication between the charging circuit and the lifting circuit to maintain the header at a selected height, or communicating the charging circuit with the lifting circuit in a manner to lower the header,said lifting circuit including a master cylinder flow path between the master cylinder and the control system, a connecting flow path between the master cylinder and the slave cylinder, and a slave flow path between the slave cylinder and the control system,said control system being operable to prevent flow from the master cylinder along the master cylinder flow path and to prevent flow from the slave cylinder along the slave flow path, when the control system is in the hold mode.