Dr. Johannes Heidenhain Gmbh

Alfred Affa

Johannes Haunreiter

Alfons Ernst

Michael Hermann

A length measuring device for measuring a relative position of two objects, the length measuring device including a scale in a housing and a scanning unit displaceable in a measuring direction X relative to the scale and the housing, wherein the scanning unit is disposed inside the housing and including a heat-generating electrical component. The length measuring device further including a thermal conduction path designed for transferring heat generated at the heat-generating electrical component to the housing.

Length measuring device

An arrangement for fastening a support of a scale of a linear measuring device on a mounting surface of an object to be measured. The arrangement includes a clamping jaw and a force-exerting element urging the clamping jaw against the support. The clamping jaw acts together with the support in such a way that the clamping jaw urges said support with a clamping force that includes 1) a first force component against the mounting surface by the force-exerting element and 2) a second force component that urges the support against an attachment face extending transversely to the mounting surface. The attachment face is directly constituted by an attachment body, which can be fixed positively and free of play in a receptacle on the object to be measured.

Arrangement for fastening a support of a scale and method for fastening the support, as well as a linear measuring device

A linear measuring arrangement for measuring a relative position of two objects, the linear measuring arrangement including guide surfaces, a scale having a measuring graduation and a scanning carriage for scanning the measuring graduation, wherein the scanning carriage is linearly guided in a measuring direction on the guide surfaces. The linear measuring arrangement further including a carrier device which can be fastened to one of the two objects and a coupling, by which the scanning carriage is coupled to the carrier device rigidly in the measuring direction and transversely thereto resiliently. The coupling includes a first coupling element, having a first coupling face, arranged on the scanning carriage and a second coupling element, having a second coupling face, arranged on the carrier device, wherein the second coupling face contacts the first coupling face and wherein at least one of the first and second coupling elements is made of a ceramic material at least in an area of a contact.

Linear measuring arrangement

A linear measuring arrangement for measuring a relative position of two objects. The linear measuring arrangement includes a unit having a housing and a scale in the housing and a scanning unit, which can be shifted relative to the unit in a measuring direction, wherein the scanning unit is arranged inside the housing and includes a heat-generating electrical component. The arrangement further includes a mounting piece, which is fastened to the scanning unit by a coupling, which is rigid in the measuring direction and resilient transversely thereto, and which extends to a mounting area arranged outside of the housing. The arrangement further includes a heat-conducting element, which is designed for transferring heat generated by the heat generating electrical component to the mounting piece and permits relative movements between the mounting piece and the scanning unit at least transversely to the measuring direction.

Length measuring arrangement

A graduated element attachment system in a position measuring system, the graduated element attachment system including a graduated element having a circumferential face and a holder. The holder includes a plurality of resilient elements, wherein each one of the plurality of resilient elements engages the circimferential face in such a manner so that the graduated element is clasped in several directions and wherein each of the plurality of resilient elements exerts a force on the graduated element wherein the exerted forces are directed in such a manner so that the plurality of resilient elements maintain the graduated element in equilibrium.

Holder for a graduated element

A position measuring device for measuring the relative position of a first object and a second object. The position measuring device having a support body having a measuring representation, wherein the support body is attached to the first object by a translatory seating. A scanning device that scans the measuring representation along a measuring direction X, wherein the scanning device is attached to the second object. The translatory seating having an elastic adhesive layer extending in the measuring direction (X) and positioned between the support body and the first object so that a translatory distance compensation between the support body and the first object is made possible.

Position measuring device

A position measuring system in which a scale has a reference mark track with two different sequences of reference marks are provided adjacent to an incremental division track. A first sequence of reference marks are disposed at successively different intervals and a second sequence of reference marks are disposed at equal intervals. Two modes of operation are available where either the absolute position is determined by scanning either the first sequence of reference marks or the second sequence of reference marks.

In the position-measuring arrangement having a groove formed in a housing for the fastening of a measurement embodiment. So that different expansion coefficients of the housing and of the measurement embodiment will cause no measurement errors, the measurement embodiment is fastened longitudinally slidable with respect to the housing in the groove. This is achieved by providing in the zone in which the measurement embodiment is held in the groove a sealing compound. A separating layer is provided between measurement embodiment and sealing compound to provide longitudinal movement.

Low vibration fastening of a scale to a carrier of a position measuring

The housing of a position measuring arrangement is fastened over length balancing elements to a first object such as a slide of a machine tool. A measurement embodiment is mounted over a highly elastic adhesive layer on an inner surface of the housing and is scanned by a scanning arrangement. In order to achieve a low-vibration fastening of the housing, it is supported in supporting zones formed between side surfaces of the housing and the exterior surface of the slide. The free length expansion between the housing and the slide is ensured by providing an elastic adhesive layer in the supporting zone.

Low-vibration fastening for the housing of a position measuring

A position measuring apparatus of the type that includes a measuring scale and a scanning unit is provided. The measuring scale includes a measuring graduation track and a reference mark track associated with the measuring graduation track. The reference mark track includes a plurality of reference marks, a predetermined number of which are further designated as marked or unmarked. The scanning unit provides for scanning the measuring scale and evaluating the signal produced by such scanning. The apparatus also includes an operating switch associated with the scanning unit. The operating switch provides for selection of at least two modes of operation of the scanning unit: a first mode in which all the reference marks on the reference mark track are evaluated, and a second mode in which marked or unmarked reference marks on the reference track are evaluated.

Position measuring apparatus with reference marks

A longitudinal position measuring device for measuring the relative positions of two objects comprising a housing, a measuring scale, and a scanning unit for scanning the measuring scale. The housing is attached to one of the objects and a scanning unit is attached to the other of the objects by means of a fastening member and a connecting element. The scanning unit comprises a light source and four photosensitive elements. The measuring signal produced by the scanning unit and power to the light source are conducted by means of a cable through the connecting element and into the fastening member. The fastening member is rotatably mounted to the connecting rod so that the fastening member may be readily attached to the other object such as a machine cradle. The cable extends through a chamber located in the fastening member and is connected to an electrical box from which the scanning signals may be taken for conduction to either a display or an evaluation unit. The chamber is dimensioned to allow a sufficient length of cable to be stored so that undesirable stresses on the cable are not exerted during rotation of the fastening member about the connecting rod.

Position measuring instrument

An encased position measuring instrument for measuring the relative position of two objects comprises a housing, a measuring scale and a scanning unit. The measuring scale is scanned by the scanning unit which is connected to a fastening member by means of a connecting rod. The connecting rod moves through a frontal opening in the housing which is hermetically sealed by a sealing unit. To avoid undesirable constraining forces exerted on the connecting rod when the housing changes position, the sealing unit is fastened to the housing by means of rods or wires. These rods run parallel to the connecting rod and are rigid in the measuring direction but allow movement of the sealing unit at right angles to the measuring direction.

Encased position measuring instrument

A measuring system for measuring the relative position of two machine parts of a processing machine includes a scale fastened at one end by means of screws to the slide of the machine. The other end of the scale is joined by means of an adhesive layer with one end of an expansion element. The other end of the expansion element is fastened in a similar manner by means of screws to the slide. For the compensation of thermally induced length changes of the scale, the expansion element is provided with a coefficient of thermal expansion substantially greater than that of the slide piece. Thermal expansion of the expansion element is dimensioned in such a way that the measuring length of the scale is preserved in an unaltered length in the event of temperature fluctuations by means of increased compressive forces applied by the expansion element to the scale.

Measuring system

A measuring system for measuring the relative position of tool machine parts compensates for thermally-induced length changes of a spindle stock by means of a scale carrier which acts as an expansion element for a scale. This scale carrier is fastened at one end directly via a fastening element to the spindle stock and at the other end is connected with an adjacent end of the scale, which is mounted on the scale carrier so as to be shiftable in the measuring direction. If the plane of the tool connected to the spindle stock shifts by an amount .DELTA.c in the measuring direction X as a result of temperature rises of the spindle stock, the scale carrier, operating as an expansion element, acts to pivot a rotatable element having an adjustable lever ratio in order to shift the scale in the same direction. In this way, the entire thermally-conditioned displacement of the scale is also made to equal the amount .DELTA.c.

An incremental measuring instrument having a series of reference marks extending alongside a division of a scale is provided with a selector element which is slideable along the length of the scale and can be aligned with a selected one of the reference marks in order to bring the selected reference mark into operation. The position of the selector element with respect to the selected reference mark is fixed by a plurality of filler elements which cooperate with a selector element to form a column of elements arranged end to end within a guide. Holding elements at the ends of the guides preclude undesired longitudinal movement of the column of elements.

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Stein/Traun, Germany

Alfred Affa