Patent ID: 7934568

Claim:
A core removal apparatus for removing the core from a substrate, comprising: a drill tube having a driving end and an attachment end, the driving end being adapted to accept an external driving means, a drill bit coaxially attached to the attachment end of the drill tube and being capable of drilling a core of the substrate and having an inner lip at a drilling end, a ground tube disposed coaxially within the drill tube and drill bit and having a driving end and a collecting end, the driving end of the ground tube having at least one notch, the collecting end of the ground tube being adapted to fit within the inner lip of the drill bit and having a conical feature, a collet tube disposed coaxially within and being rotationally coupled but not axially coupled to the ground tube and having a driving end and a collecting end, the driving end of the collet tube extending beyond the driving end of the ground tube and having an outwardly threaded region, the collecting end of the collet tube being adapted to fit within the inner lip of the drill bit and having a plurality of fingers capable of flexing radially inwards when an external force is applied thereon, the conical feature at the collecting end of the ground tube and the fingers being adapted to cause the fingers to flex radially inwards when the collet tube is displaced axially with respect to the ground tube, an ejection rod located coaxially within the collet tube adapted to move axially within the collet tube, and a driving system engaging the ground tube and collet tube, comprising: an axial framework, the driving end of the ground tube being held axially fixed with respect to the axial framework, a collet nut threadedly disposed around the outwardly threaded region of the driving end of the collet tube and being held axially fixed and rotationally free with respect to the axial framework, and a rotational lock held rotationally fixed relative to the axial framework and containing at least one locking tab capable of engaging the notch on the driving end of the ground tube in order to rotationally couple the ground tube to the axial framework.