Patent ID: 7669667

Claim:
An aerator for punching a plurality of holes in the ground, which comprises: (a) a frame supported for movement over the ground by a plurality of wheels; (b) a coring head carried on the frame, the coring head having a plurality of side-by-side tine assemblies that are vertically reciprocal for punching holes in the ground, the tine assemblies being vertically reciprocated by a plurality of drive arms with one drive arm reciprocating one tine assembly; (c) a drive member that is rotatable about an axis of rotation and serves as an input power source for reciprocating the drive arms up and down; and (d) a crankshaft for converting the rotation of the drive member to reciprocating motion of the drive arms up and down, wherein the crankshaft has a plurality of crank members that are separate from the drive arms with each crank member being connected to an upper end of one drive arm, and wherein the crankshaft comprises: (i) a first crank member that is rotatable about the axis of rotation of the drive member, the first crank member being rotatably fixed to the drive member to be directly rotated by the drive member, the first crank member having a hub that is parallel to the axis of rotation of the drive member but is off the axis of rotation of the drive member with the upper end of a first drive arm being pivotally coupled to the off axis hub of the first crank member; (ii) a second crank member that is also rotatable about the axis of rotation of the drive member, the second crank member also having a hub that is parallel to the axis of rotation of the drive member but is off the axis of rotation of the drive member with the upper end of a second drive arm being pivotally coupled to the off axis hub of the second crank member; and (iii) a coupler to which the first and second crank members are removably secured by a plurality of fasteners such that the first and second crank members and the coupler all collectively rotate together about the axis of rotation of the drive member as at least part of a single crankshaft when the fasteners are tightened, wherein the coupler includes at least one compressible cushion interposed between the first and second crank members to take up and absorb misalignment between the first and second crank members as the first and second crank members are secured to the coupler and the fasteners are tightened.