Dr. Johannes Heidenhain Gmbh

Johannes Heidenhain Gmbh

Holmer Dangschat

Alfons Ernst

Horst Burkhardt

Gerald Metz

Christian Spaeth

Horst Wogatzke

A device for determining the position of an object that is movable along at least one displacement direction, the or each displacement direction having assigned to it one length measuring device for measuring the position of the object along the respective spatial direction, includes: at least one scale extending along a displacement direction of the object to be measured as a first component of the respective length measuring device; a scanning head for scanning the scale as a second component of the respective length measuring device such that a change in the position of the scale with respect to the scanning head along the associated displacement direction of the object to be measured is measurable, one of the two components of the respective length measuring device being moved together with the object to be measured along the respective displacement direction when the latter is moved; and a device for determining the distance of the component of the respective length measuring device, which is movable together with the object to be measured, from the object to be measured along the measuring direction of the associated length measuring device. The device for determining the distance of the component of the respective length measuring device, which is movable together with the object to be measured, from the object to be measured includes a measuring graduation as a first module and an associated measuring head as a second module, one of the two modules being provided on the object to be measured and the other of the two modules being provided on the component of the length measuring device that is movable together with the object to be measured.

Device for determining the position of an object movable along at least one displacement direction

A position measuring system for measuring the relative position of two objects movable with respect to one another includes a housing which rotatably supports a shaft connected with the first object. A first graduation disk with a first incremental graduation and at least one absolutely positioned first reference mark is mounted to rotate with the shaft. A first scanning unit for the scanning of the first incremental graduation and the first reference mark is rotatably mounted on the shaft to rotate relative to the first graduation disk and the housing. A second graduation disk is firmly connected to the first scanning unit. The second graduation disk defines a second incremental graduation and at least one absolutely positioned second reference mark. A second scanning unit is fixedly mounted to the housing which is connected to the second object. In order to reproduce a reference position after an interrupted measurement operation and unknown movement of the relative position of the two objects, the first scanning unit is rotatable together with the second graduation disk for the scanning of the first reference mark of the first graduation disk and for the scanning of the second reference mark of the second graduation disk. The distance between the two reference marks is counted in a differential counter.

Position measuring system comprising at least two scanning units

A coupling device for connecting a standard incremental angular motion transducer with two objects to be measured wherein the transducer is of the type comprising a measuring scale with at least one reference mark and a scanning unit operative to scan the measuring scale. The coupling device enables the transducer to be calibrated while the two objects are stationary. The calibration process is performed using a motor which engages and rotates a gear wheel connected to the measuring scale. The rotation of the measuring scale is conducted against the force of a spiral spring until the reference mark is scanned by the scanning unit and a reference pulse generated. The measuring scale is then returned to its momentary position under the influence of the spiral spring and the motor disengaged.

Coupling device

A position measuring system includes for the determination of a reference position at least one additional reference scanning unit which is shiftable relative to the measuring scale, independently of the measuring scanning unit and the measuring scale, and accordingly of the machine components connected to the measuring scanning unit and the measuring scale. The measuring scale carries an incremental graduation and a reference mark, and the measuring scanning unit and the reference scanning unit carry indicator blocks which on coincidence form a zero indicator. In order to determine the reference position, the reference marks and the zero indicator are scanned successively, but in arbitrary sequence, and their differential spacing is determined with the aid of a graduation of the reference scanning unit.

Position measuring system

A calibration process and apparatus are disclosed for allowing a reference position to be determined at any time, independent of the momentary position of the two objects movable relative to one another to be measured. One of the two objects to be measured is decoupled from the measuring device and then either the scanning plate or the measuring graduation of the measuring device is moved until it comes into alignment with a reference mark. This scanning of a reference mark causes a counter included in the measuring system to be set at a predetermined value such as zero. From this point up to the point the scanning plate or measuring graduation is returned to the momentary starting position, the grid lines of the graduation on the graduated plate are counted. In this way, the absolute position of the momentary starting position is determined. After all components of the measuring device have been returned to the momentary starting position, the measuring position is re-established, and the working operation can be resumed.

Method and apparatus for reproducing a reference position in an

A play-free precision drive apparatus is disclosed which comprises a rotatable drive element (2, 20) for driving a driven element (8, 21), a biasing element (12, 26) for urging the driven element (8, 21) into engagement with the drive element (2, 20), and two rotatable support elements (11, 22) abutting the drive element (2, 20) along its periphery for holding the drive element (2, 20) against the driven element (8, 21). The support elements (11, 22) are positioned such that the centers of the support elements (11, 22) and the center of the drive element (2, 20) define an angle (A.sub.1, A.sub.21) of less than 180.degree. having its apex at the center of the drive element (2, 20) and such that the centers of the support elements (11, 22) define a line (L.sub.3, L.sub.23) parallel to a tangent to the drive element (2, 20) which passes through a contact point between the drive element (2, 20) and the driven element (8, 21). Although the drive element (2, 20) and the support elements (11, 22) are mounted on standard bearings which have play, the precision drive apparatus has substantially no play in the direction of drive.

Play-free precision drive apparatus

a precision measuring apparatus (0) defining a measuring interval sealed from environmental influences comprises a shielding housing (10) surrounding a measuring interval and defining within the housing wall a slit (10a) oriented along the measuring interval, a movable member (11) attachable to a measured object and movable along the measuring interval, a carrying member (1a) attached to the movable member (11) and extending through the slit (10a), fluid bearings (12b) interposed between the movable member and the shielding housing to form a bearing gap (12) therebetween and to movably support the movable member (11) on the shielding housing (10) substantially without friction, and sealing fluid (14c) positioned in the bearing gap (12) to seal the slit (10a). The apparatus further includes a fluid supply means (14) for supplying sealing fluid (14c) such as vacuum oil, to the bearing gap (12), and means (18) for evacuating the shielding housing (10). A channel (13b ) for distributing the sealing fluid (14c) from the supply means (14) through the bearing gap (12) is defined by the movable member (11). Channels (13a, 13c) for collecting sealing fluid (14c) in the bearing gap (12) are defined by the wall of the housing (10). The fluid bearings (12b) can be pneumatic, formed by injecting compressed air into the bearing gap (12).

Precision measuring apparatus having a measuring interval sealed from

An adjustable table is described having three support structures arranged symmetrically around the perimeter of the table. Each support structure is supported on a base by means of a two dimensional joint, such as a leaf spring, having an axis of rotation tangential to a circle centered at a central point of the table. Each support structure supports the table by means of a three dimensional joint such as a ball in socket joint. Each support structure includes a threaded spindle and a rotatable threaded bolt for adjusting the separation between the table and the base.

Precision adjustable table

A driving apparatus for rotating a rotary table is described including a drive mechanism and a guide apparatus. The drive mechanism includes a drive roller which contacts a peripheral surface of the rotary table to rotate the table, a support element and a press-on element which hold the drive roller against the table and apply compensating forces which prevent the drive mechanism from applying distorting forces to the support bearings of the table. The drive mechanism is guided at the periphery of the table by a pair of guides which permit substantially friction free translation of the drive mechanism in a plane perpendicular to the axis of rotation of the table while preventing rotation of the drive mechanism or translation out of the plane.

Growing community of inventors

Traunreut, Germany

Holmer Dangschat