Patent ID: 7481011
Filing Date: 2009-01-27
Classification: E01H

Abstract:
1. A blade assembly comprising: (a) a main body including a first end, a second end, and a generally vertical blade portion; (b) a first wing operatively pivotally mounted adjacent the first end and a second wing operatively pivotally mounted adjacent the second end of the main body; (c) a first hydraulic cylinder operatively connecting the first wing to the main body and a second hydraulic cylinder operatively connecting the second wing to the main body, the first hydraulic cylinder extending from the main body to a first cylinder mounting location on the first wing, the second hydraulic cylinder extending from the main body to a second cylinder mounting location on the second wing, the first and second cylinders constructed for pivotally moving said wings relative to said main body, said cylinders being operatively connected in a series-type hydraulic circuit; (d) wherein the distance from the first end of the main body, where the first wing is pivotally mounted, to the first cylinder mounting location defining a first swing radius is longer than the distance from the second end of the main body, where the second wing is pivotally mounted, to the second cylinder mounting location defining a second swing radius, wherein each wing is configured to rotate through a range of rotation substantially equal that of the other wing, wherein the difference in the first and second swing radii provides varying rates of rotation between the first and second wings to compensate for fluid loss between the cylinders in the series-type hydraulic circuit.