Lifting arrangement for agricultural implement frame

Claim 1

In an agricultural implement having a frame, a pair of lever members each mounted from said frame for oscillation relative thereto about a pivot axis, and a pair of ground engaging wheels each mounted on a corresponding one of said lever members for rotation about a rotational axis spaced a predetermined distance from said pivot axis, the combination therewith of means for elevating the frame relative to land traversed and for minimizing tilting of said frame during elevation, said means comprising: first and second pressure fluid actuator means for moving said lever members in oscillation and thereby for raising said frame upwardly, said first and second actuator means including first and second cylinders of common inside diameter, first and second pistons movable within corresponding ones of said cylinders, and first and second piston rods operatively connected to corresponding pistons and extensible relative to corresponding cylinders, and pressure fluid circulating means for supplying fluid under pressure to said actuator means, said circulating means including conduit means connecting said second actuator means in series with said first actuator means for displacement of fluid from the piston rod end of said first actuator means to the cylinder end of said second actuator means on extension of said piston rods whereby the stroke of said second piston rod is less than the stroke of said first piston rod, said first and second actuator means each being connected between said frame and a corresponding one of said lever members for pivoting said lever members on extension and retraction of said piston rods and with the connection of said second actuator means to said corresponding lever member being spaced from said corresponding pivot axis a distance less than the distance between the connection of said first actuator means to said corresponding lever member and said corresponding pivot axis whereby the movement of said wheels relative to said frame is equalized notwithstanding the inequality in strokes of said actuators means.