Patent ID: 7188690

Claim:
A drilling device for producing undercut holes, said drilling device comprising: a drilling tool comprising a drill shaft that defines an axis of rotation of said drilling tool and a cutter carried at an end region of said drill shaft such that, in use, it drills a hole having a longitudinal axis that is radially offset with respect to said axis of rotation; and a centering device operable to apply a lateral force to said drilling tool for moving said axis of rotation towards said longitudinal axis to cause said cutter to form an undercut in a said hole, said centering device including; a centering member that is movable from a non-operative position outside of said hole to an operative position inside said hole in which the member is positioned between said drill shaft and a wall defining said hole so as to provide said lateral force; an operating device connected with said centering member by which an operator can move said centering member from said non-operative position to said operative position; a depth stop device by which a drilling depth of said hole is set; and a control device for said operating device, said control device being configured to prevent movement of said operating device by which said centering member is moved from said non-operative position to said operative position until said drilling tool has drilled said hole to said drilling depth set by said depth stop device.