Patent ID: 7458430

Claim:
An attachment device for a ground drilling or cutting tool that enables cutting elements to be movably secured to said tool, said cutting elements having a cutter and an arm that has a longitudinal axis, a first surface defining a dowel hole, and an engagement surface that extends substantially parallel to the longitudinal axis, said attachment means including: a second surface on said tool upon which said first surface locates, defining a dowel hole aligned with the dowel hole in the first surface when said first and said second surfaces locate together, a dowel that locates in said first and said second dowel holes when the dowel holes are aligned with one another; said tool and said cutting element having engagement features that include a projection received in a channel so as to resist side loads applied to said cutting-element, a plurality of threaded fasteners having a preselected diameter, for securing said arm to said tool, threaded apertures defined in said second surface of said tool, on either side of said engagement features, that are threadingly engaged by said threaded fasteners, portions of said arm disposed on either side of said cutting element and on one side of said cutter, defining through holes extending through said arm, to receive and locate said threaded fasteners for threading engagement with said tool; and said through holes providing clearance between the arm and said threaded fasteners so that said threaded fasteners are substantially disengaged from loading applied through said arm to at least one of said dowel and said engagement features.