Patent ID: 7726109

Claim:
A method of suspending a header from a towed implement to permit the header to float, the towed implement comprising a main frame, a sub-frame, and a four-bar linkage system comprising an upper link and a lower link, the method comprising: (a) operatively, pivotally attaching a first end of the lower link to the main frame of the towed implement using a first spherical bearing; (b) operatively, pivotally attaching a second end of the lower link to the sub-frame using a second spherical bearing; (c) operatively, pivotally attaching a first end of the upper link to the main frame using a first cylindrical bearing; (d) operatively, pivotally attaching a second end of the upper link to the sub-frame using a third spherical bearing; and (e) operatively attaching the header of the towed implement to the sub-frame; (f) operatively, pivotally affixing an actuator to the sub-frame above the upper link; (g) applying a force to the sub frame with the actuator in a direction toward the main frame; (h) placing the lower link in tension due to the force; (i) raising the sub-frame due to the force; and (j) permitting the sub-frame to self-level due to the tension in the lower link.