Patent ID: 6283488
Filing Date: 2001-09-04
Classification: A01B

Abstract:
A control device in combination with two lower steering arms of a tractor, a hydraulic power lift for lifting or lowering the two lower steering arms, each lower steering arm actuable by one side strut, each side strut having a hydraulic cylinder, said hydraulic power lift connected to a first pressure source and said control device comprising:a second pressure source;a switchable pre-selection valve; anda switchable control valve;said pre-selection valve having a first port connected to the first pressure source, a second port connected to the second pressure source and an outlet port connected to an inlet port of the control valve, and said pre-selection valve switchable to connect either the first pressure source or the second pressure source to the inlet port of the control valve;said control valve switchable to a first position jointly connecting the two hydraulic cylinders to the inlet port and to a second position jointly connecting the two cylinders to a return flow means wherein said two hydraulic cylinders enable the two lower steering arms of the tractor to float sideways.