Patent ID: 7775303

Claim:
An apparatus for a drilling tool, comprising: a pilot drilling bit; a reamer; and a pilot body which is disposed to support the reamer and the pilot drilling bit at the end of a casing tube, wherein the reamer includes a closed position in which the reamer is located radially inside the casing tube and displaceable through the casing tube, and an open position in which at least a part of the reamer is located radially outside the casing tube, wherein the pilot body comprises a male portion which extends through the reamer and is inserted into a recess in the pilot drilling bit, the male portion of the pilot body forming a cam surface for transferring rotation energy to the reamer and for switching the reamer between said closed and open positions, and wherein the male portion comprises a first portion having an oblong-shaped cross section and located radially inside an upper axial end of the reamer, and a second portion having a diameter which is less than a diameter of the first portion and located radially inside a lower axial end of the reamer which is adjacent the pilot drilling bit.