Dr. Johannes Heidenhain Gmbh

Johannes Heidenhain Gmbh

Bizerba-werke Wilhelm Kraut K.g.

Horst Burkhardt

Alfons Ernst

Holmer Dangschat

Alfons Baumgartner

Gunther Nelle

Ernst Schwefel

Norbert Vollmayr

Hans-Rudolf Kober

Michael Rauth

Helmut Schlick

Josef Huber

Walter Berg

Jurgen Laubin

Anton Mayer

Horst Wogatzke

A position measuring arrangement for the measurement of the relative position of two objects shiftable with respect to one another wherein the measuring graduation is connected with the first object and is scanned by a scanning unit fastened to the second object. Four binary scanning signals are produced by the scanning unit with a predefined relative phase relationship. The signals are applied to a logic network for the generation of a linked binary signal. In the case of no errors, the linked binary signal is equal to a selected one of the four binary signals. In the event of an error, the linked binary signal is not equal to the selected one of the binary signals. The linked binary signal and the selected binary signal are applied to a comparator for a determination of equality and thereby a determination of the presence of errors.

Incremental position measuring instrument with error detection

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

An incremental measuring system is disclosed in which a reference position can be determined at any time. A rotating carrier body carries an additional incremental graduation for which scanning fields are arranged on a scanning plate. During a calibrating operation an additional marking on the rotating carrier body is used to determine coincidence with an associated scanning field. At this point a measuring value counter is started which counts graduation increments associated with rotation of the carrier body by means of associated scanning fields until the measuring value counter is stopped. This stopping of the counter is controlled by a signal generated on coincidence of an additional marking of the carrier body with the next reference mark on the graduated disc which carries the measuring graduation. Simultaneously, an additional marking of the carrier body reads a code mark associated with the reference mark. Each of the code marks contains in coded form the absolute position of the associated reference mark with respect to the zero point of the measuring graduation. The reference position is determined from the counting value of the increments which are superposed on the absolute position value of the overrun reference mark.

Incremental length or angle measuring system

A length measuring instrument includes a flexible measuring band which slides in a groove defined by a scale carrier body. The measuring band is fixed at one end to the carrier body. The second, free end of the measuring band is fastened in an oscillator which excites this free end into high frequency, low amplitude vibrations. These vibrations act virtually to eliminate harmful friction between the measuring band and the scale carrier body, and to reduce fouling of the measuring band markedly.

Length or angle measuring device

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 length or angle measuring system is provided in which for the purposes of error correction the graduation of the measuring scale is scanned on both sides of the graduation axis which runs along the measuring direction. The weighting given to the two sides of the measuring graduation is varied according to the desired error correction course. Several different approaches to varying this weighting are disclosed, including the mounting of a scanning unit so as to be shiftable transversely to the graduation axis of the graduation.

Error correction system for position measuring device

A length measuring system of the type having a division on a scale which is scanned by a scanning unit in order to measure the relative position of a slide with respect to a bed of a machine is disclosed. In order to correct division errors and/or machine errors between a follower fastened to the slide and the scanning unit, there is arranged an electromechanical adjusting element between the follower and the slide. In a first preferred embodiment, this adjusting element takes the form of a piezoelectric element, which, in accordance with electric correction signals applied thereto, varies in length and thereby corrects the relative position of the scanning unit and the follower in accordance with the desired error correction course. Alternate embodiments employ magnetostrictive cores and electromagnetic coil arrangements to accomplish the desired error correction.

Error correction arrangement for digital length or angle measuring device

A numerically controlled machine tool for producing tangential entry into a compensated contour and for the tangential leaving from a compensated contour. The numerically controlled machine tool also produces the interior or exterior rounding of intersections between two contours.

NC Machine for producing tangential entry to and exit from a compensated

An improvement is disclosed for an encapsulated measuring device used for measuring the relative position of two objects. The improvement comprises a pair of sealing lips, each secured at one edge to a housing for the measuring device, and together covering an opening in the housing. The lips each define regions of greater flexibility adjacent to regions of lesser flexibility. A follower passes through the opening between the sealing lips. The sealing lips operate to maintain a seal for the opening while permitting the follower to pass between them. The lips are constructed such that openings adjacent to the follower are minimized or eliminated, and little frictional force is exerted on the follower if it moves in the opening along a measuring direction. The result is that accurate measurement is possible while intrusion of debris into the housing is largely prevented due to the seal.

Sealing element for encapsulated measuring device

A photoelectric measuring apparatus includes a measuring scale and a scanning unit including at least one photosensitive element for generating a scanning signal in response to light incident on the scanned region of the scale. First and second light sources are included, as well as a mechanism for selecting either of the first and second light sources such that light from the selected light sources is directed at the scanned region of the scale. A slider mechanism, a turntable, a movable mirror, or a movable prism can be used to select either the first or second light sources. In addition, a circuit is disclosed which provides separate first and second balancing circuits for the respective light sources, such that rebalancing the measuring instrument is not required when the selecting mechanism is used to select a different light source.

Photoelectric digital measuring instrument having multiple light sources

An improved electronic counter for use with an incremental measuring device is disclosed. The counter includes two or more individual counters, a display unit, and a switch for selectively connecting any one of the individual counters with the display unit. Each of the individual counters may be individually set to a separate zero point so that each counter may be used to store a position value in a separate frame of reference. The position value stored in any one of the individual counters may be switched to the display unit without disturbing the contents of the other individual counters. In the preferred embodiment, the counter includes a circuit for automatically resetting a first individual counter to zero whenever the measuring device senses a predetermined reference mark, thereby automatically maintaining a calibrated zero point in that counter. The preferred embodiment also includes a power fail circuit which generates a warning signal when the measuring device is operated following an interruption in the line voltage used to power the device. This warning signal is maintained until the first individual counter is automatically reset, and the device is again calibrated for use.

Counter system for incremental measuring instrument

An improved counter for use with an incremental measuring device is disclosed which includes an up-down counter, a plurality of memory units, a computer, and means for designating any of the memory units. The computer is coupled to the counter and the memory units and is programmed to algebraically combine the value stored in the counter with the value stored in the designated memory unit to generate an output value for display. In the preferred embodiment, circuits are provided for setting the individual memory units to preselected values. The counter of this invention can be used to selectively display the measured position in any one of several measurement modes by designation of the appropriate memory unit.

Electronic counter for incremental measuring device

An encapsulated measuring device is described which includes a hollow body, a scale defining a measuring direction, and a sensing unit disposed to move along the scale within the hollow body. An entrainment member is pivotably secured to the sensing unit and extends out of the hollow body. Sealing members provide a seal between the movable entrainment member and the hollow body, and these sealing members protrude beyond the hollow body so that liquid in the hollow body can flow down onto the sealing members and out of the hollow body through openings between the sealing members and the entrainment member. Because the pivotable articulation allows the entrainment member to be adjusted with respect to the sensing unit, the angle at which the entrainment member protrudes from the hollow body may be adjusted according to the requirements of the individual installations. The configuration of the sealing members allows fluid to drain from the hollow body for a range of orientations of the entrainment member.

Encapsulated measuring device

An error preventing incremental measuring system utilizes a plurality of scanning elements associated to a relatively movable divided scale. But, instead of merely comparing the results of a plurality of independent channels originating at the scanning elements and terminating at separate counters, the system according to the invention combines the signals from the scanning elements by way of a logical network into a further signal similar resp. dissimilar to one or more of the scanning signals, thus avoiding the necessity of fault tolerances.

Growing community of inventors

Truchtlaching, Germany

Horst Burkhardt