Grapple skidder with self-centering grapple support mechanism
AssigneeClark Equipment Company
InventorStanislaus H. Koch
Life of this patent
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Abstract
A material handling vehicle, especially a log skidder, having articulated front and rear sections and a boom mounted on the rear section which pivotally supports a material handling member such as a grapple adapted to seize the ends of logs to be moved by the skidder. The grapple hangs from the end of the boom on a selfcentering mechanism which includes a plurality of first circular discs, a plurality of second circular discs interleaved therewith with the uppermost disc being fixed and interacting between discs, a plurality of spring elements which resist rotation of the grapple in either direction about the grapple turning axis tending to return it to a normally centered position relative to the centerline of the vehicle without operator assistance.
Claims5
In a grapple skidder vehicle having a front section including drive wheels, a rear section including drive wheels, means for driving the wheels, means interconnecting the front and rear sections for relative pivotal movement between the sections about a substantially vertical axis, the improvement comprising a grapple support boom, a grapple pivotally suspended from said grapple support boom, a grapple centering mechanism carried on the grapple support boom and pivotally supporting said grapple, said grapple centering mechanism including a housing fixed against rotation about the grapple turning axis, first torosional resistance means in said housing having its upper end secured thereto, second torsional resistance means in said housing having its lower end connected to the grapple for pivotal movement therewith, and a yieldable connection means between said first and second torsional resistance means establishing a neutral position of relative angular deflection between said first and second torsional resistance means when the grapple is disposed transversely to the centerline of the vehicle and progressively increasing torsional resistance forces acting on the grapple in either direction from said neutral position regardless of the load being carried by the grapple.
Dependencies are inferred from the claim text.