A retractable auger boring cutter head. The cutter head has fixed cutters and at least one pivoting cutter. The pivoting cutter is biased to a position that extends beyond a diameter of a casing being installed. When pulled back through the casing, a surface of the pivoting cutter contacts the casing, reducing the effective diameter of the cutter head and allowing it to be removed.

In a cutting tool (106) for a tunnel boring machine, a tool head (115) equipped with at least one wear sensor (315) is present that is detachably connectable to a tool holder (206, 321). A line arrangement having a wireless, connector-free coupling module (312) between the tool head (115) and the tool holder (206, 321) is provided for connecting the or each wear sensor (315) to an evaluation module (330). In this way, in the event of wear, a tool head (115) to be replaced may very easily be removed from the tool holder (206, 321) and a new tool head (115) may be connected to the tool holder (206, 321) very easily and in an electrically safe manner. A tunnel boring machine equipped with at least one cutting tool (106) of this type is thus operable in a very efficient manner.

A cutting tool for a tunnel boring machine, including a tool head equipped with a wear sensor detachably connectable to a tool holder. A line arrangement having a wireless, connector-free coupling module between the tool head and the tool holder is provided for connecting the wear sensors to an evaluation module. In the event of wear, a tool head to be replaced may be removed from the tool holder and a new tool head may be connected to the tool holder.

A retractable auger boring cutter head. The cutter head has fixed cutters and at least one pivoting cutter. The pivoting cutter is biased to a position that extends beyond a diameter of a casing being installed. When pulled back through the casing, a surface of the pivoting cutter contacts the casing, reducing the effective diameter of the cutter head and allowing it to be removed.

A method, an arrangement and a machine for powering holes in mountains through so-called full face reaming. According to the method according to the invention a plurality of cutterheads (20:1-20:n) independently of each other are displaceably moveably accommodated in a drill head (11) by operation of a linear drive arrangement (22:1-22:n) for each cutterhead (20:1-20:n), and which cutterheads from a condition retracted in the drill head (11) are conveyable to a projecting mountain-grinding condition from the front side (11) simultaneously with the drill head (11) rotating, whereby the hole front is gradually drilled along concentric rings drill rings that go from an inner smallest circle to an outer largest circle by new cutterheads (20:1-20:n) with gradually increasing radius from the centre of the drill head in successive steps are conveyed in mountain-grinding condition.

A method, an arrangement and a machine for powering holes in mountains through so-called full face reaming. According to the method according to the invention a plurality of cutterheads (20:1-20:n) independently of each other are displaceably moveably accommodated in a drill head (11) by operation of a linear drive arrangement (22:1-22:n) for each cutterhead (20:1-20:n), and which cutterheads from a condition retracted in the drill head (11) are conveyable to a projecting mountain-grinding condition from the front side (11) simultaneously with the drill head (11) rotating, whereby the hole front is gradually drilled along concentric rings drill rings that go from an inner smallest circle to an outer largest circle by new cutterheads (20:1-20:n) with gradually increasing radius from the centre of the drill head in successive steps are conveyed in mountain-grinding condition.