A method is described for determining a relative position of an axis of rotation of a rotary table of a coordinate measuring machine. The rotary table has or forms a reference element that is arranged eccentrically in relation to the axis of rotation. The method includes a measuring step including performing a rotary movement of the rotary table, and producing measuring points that encode a position of the reference element by a sensor of the coordinate measuring machine during the rotary movement. The method includes a determining step including determining the relative position of the axis of rotation of the rotary table based on the measuring points.

A method for positioning a body that has a surface extending along a circular arc, includes: attaching the body to a machine part that is capable of swiveling; attaching a stationary, first distance gauge; attaching a stationary, second distance gauge; determining three first distance values and three second distance values at three defined angular positions of the machine part different from each other; calculating a first offset value, based on the three first distance values and the corresponding angular positions, and a second offset value, based on the three second distance values and the corresponding angular positions; shifting the body relative to the machine part, until the first offset value is determined by the first distance gauge and the second offset value is determined by the second distance gauge within permissible tolerances.

A monitoring system (100) monitors displacement of a wind turbine tower and includes at least one plumb bob with an upper part and a lower part, each plumb bob being configured to be pivotally suspended at its upper part, via a suspension device, from a point above so as to attain a rest position in a rest situation, and each said plumb bob has one or more sensing surfaces (12, 12′). One or more suspension devices means (10) suspend the at least one plumb bob. Two or more sensors (14, 14′, 14″), each being configured to sense, in a specific sensing direction (16, 16′, 16″), a distance to a plumb bob, provide displacement data. At least two of the two or more sensors (14, 14′, 14″) are arranged in a sensing vicinity of a plumb bob, with at least two of the specific sensing directions (16, 16′, 16″) not being parallel to each other. The monitoring system includes a control unit (18) configured to receive the displacement data from two or more of the sensors, and a device for reporting, to an external unit (20), parameter(s) representing displacement of a wind turbine tower.

A method for mounting a sensor bearing unit providing a bearing and an impulse ring provided with a target holder and with a target mounted on an axial portion of the target holder. The method including measuring an eccentricity E.sub.1 between the target and the axial portion of the target holder, measuring an eccentricity E.sub.2 between a groove made in the bore of an inner ring of the bearing and the bore, introducing the target holder inside the groove, turning the target holder inside the groove to an angular position in which the eccentricity E.sub.total between the target and the bore of the inner ring is less than or equal to a predetermined value which is lower than the sum of the eccentricities E.sub.1 and E.sub.2, and securing the target holder inside the groove of the inner ring at the angular position.

A method for mounting a sensor bearing unit providing a bearing and an impulse ring provided with a target holder and with a target mounted on an axial portion of the target holder. The method including measuring an eccentricity E.sub.1 between the target and the axial portion of the target holder, measuring an eccentricity E.sub.2 between a groove made in the bore of an inner ring of the bearing and the bore, introducing the target holder inside the groove, turning the target holder inside the groove to an angular position in which the eccentricity E.sub.total between the target and the bore of the inner ring is less than or equal to a predetermined value which is lower than the sum of the eccentricities E.sub.1 and E.sub.2, and securing the target holder inside the groove of the inner ring at the angular position.

A method for positioning a body that has a surface extending along a circular arc, includes: attaching the body to a machine part that is capable of swiveling; attaching a stationary, first distance gauge; attaching a stationary, second distance gauge; determining three first distance values and three second distance values at three defined angular positions of the machine part different from each other; calculating a first offset value, based on the three first distance values and the corresponding angular positions, and a second offset value, based on the three second distance values and the corresponding angular positions; shifting the body relative to the machine part, until the first offset value is determined by the first distance gauge and the second offset value is determined by the second distance gauge within permissible tolerances.

Provided is a reference point indicating apparatus, which is comprises an equilateral parallelogram being formed with rotatable link points, contacts provided at tips of extending portions obtained by extending respective sides of the equilateral parallelogram, a link plate for linking between middle points of one set of opposing sides of the equilateral parallelogram, and an indicator provided on the link plate, wherein the contacts are capable of abutting on an object by expansion and contraction of the equilateral parallelogram, wherein the indicator is configured to indicate a reference point of the object in a state where the contacts abut on the object.

A radial force device for a contour measuring instrument for measuring a contour of a shaft-shaped workpiece which can be rotated about an axis of rotation. The radial force device has a clamping body, a force introduction roller, at least one counter-roller and a coupling device. The clamping body is shaped for fitting radially around a workpiece portion, received in the contour measuring instrument, of the workpiece. The force introduction roller is designed to apply a mechanical radial force to the workpiece in order to apply a load to the workpiece, wherein the force introduction roller is mounted in a radially movable manner on the clamping body. The counter-roller is mounted in the clamping body and designed to support the workpiece during the application of the force. The coupling device is shaped for coupling the clamping body to the contour measuring instrument.

A method for mounting a sensor bearing unit providing a bearing and an impulse ring provided with a target holder and with a target mounted on an axial portion of the target holder. The method including measuring an eccentricity E.sub.1 between the target and the axial portion of the target holder, measuring an eccentricity E.sub.2 between a groove made in the bore of an inner ring of the bearing and the bore, introducing the target holder inside the groove, turning the target holder inside the groove to an angular position in which the eccentricity E.sub.total between the target and the bore of the inner ring is less than or equal to a predetermined value which is lower than the sum of the eccentricities E.sub.1 and E.sub.2, and securing the target holder inside the groove of the inner ring at the angular position.

A method for mounting a sensor bearing unit providing a bearing and an impulse ring provided with a target holder and with a target mounted on an axial portion of the target holder. The method including measuring an eccentricity E.sub.1 between the target and the axial portion of the target holder, measuring an eccentricity E.sub.2 between a groove made in the bore of an inner ring of the bearing and the bore, introducing the target holder inside the groove, turning the target holder inside the groove to an angular position in which the eccentricity E.sub.total between the target and the bore of the inner ring is less than or equal to a predetermined value which is lower than the sum of the eccentricities E.sub.1 and E.sub.2, and securing the target holder inside the groove of the inner ring at the angular position.