The tool further has a rotation prevention mechanism projecting from the housing outward in the band width direction and restricting the rotation of the housing (5) caused by tightening torque of the worm screw.

In one embodiment, the compression of the locking screw is achieved through a torquing action.

Tightening of the clamping screw within the clamping screw orifice removably joins the barrel to the barrel housing.

The rotation of the securing element or coupler applies a torque on the bone anchor screw thereby placing the screw into bone.

The latter comprises a tensioning screw (50), which is used to clamp the tensioning surface against the counter surface.

In an impact screw tightening device using an electric motor as the drive source for rotation, tightening torque accuracy is improved and time required for screw tightening is reduced.

When the tightener is loosened, the bolts (14) are supported by the flange (57) and act both as tightening and as loosening bolts.

Located in the clamping strip (8) are openings through which bolts can be passed.

The clamping ring comprises a clamping screw (18), by means of which the diameter of the clamping element (4) can be changed.

Instead of the clamping screw (15) an eccentric may also be provided.

The first end of the barrel housing is adapted to engage the receiver of the gun The second end of the barrel housing includes a clamp and a clamping screw orifice formed therein for receiving a clamping screw.

A metal cutting insert is clamped to the cutter support head by a clamp that is secured by a clamp screw being threaded into the clamp screw passage.

A tightening device with limited torque, provided with a screw whose maneuvering head has a cap and accommodates a disengaging element.

In the conventional practice of tightening a screw connection to a predetermined tightening torque, the invention enables the tolerance range of the pre-tensioning force corresponding to the tightening torque to be reduced.

The computing part (19) estimates tightening torque Tave based on the estimate value of the first tightening torque (T1) or the second tightening torque (T2).