Patent ID: 6318477
Filing Date: 2001-11-20
Classification: A01B,A01C

Abstract:
An agricultural implement configured to be towed by an agricultural vehicle comprising:a first frame having a first plurality of spaced-apart ground engaging tools;a second frame having a second plurality of spaced-apart ground engaging tools and pivotally coupled to the first frame;a hydraulic cylinder coupled between the first frame and the second frame to pivot the first frame with respect to the second frame about a substantially horizontal axis; anda hydraulic control circuit fluidly coupled to the hydraulic cylinder, the hydraulic control circuit 1) including a pressure regulating valve configured to provide a supply of hydraulic fluid under substantially constant pressure from a first source of hydraulic pressure to a first port of the hydraulic cylinder over a range of pivotal positions of the first frame with respect to the second frame in order to apply a down pressure on the first frame relative to the second frame, and 2) being configured to selectively couple a second port of the hydraulic cylinder to a second source of hydraulic pressure to lift the first frame relative to the ground.