Abstract: An angle encoder having bovine an incremental section and an absolute section and serving to detect angular positions of an encoder disk and the number of revolutions performed by said disk comprises an incremental measuring scale and an absolutely coded measuring scale provided on said disk and associated reading and evaluation means. In conjunction with a high angular resolution it is desired to determine any absolute position of the disk without a previous rotation of the disk. This is accomplished in that the encoder disk comprises in addition to an incremental scale an absolutely coded scale consisting of a serial bar code, from which multidigit code words are readable, which are associated with respective absolute angular positions of the disk. The absolutely coded measuring scale extends on a track that is radially offset from the incremental scale and comprises code bars having side edges which are radially aligned with the radial boundaries of the increments of the incremental scale.

Abstract: In a system comprising a laser diode and means for stabilizing the wavelength of a primary beam of light emitted by said laser diode said means comprise a controller for controlling the current supplied to the laser diode under the control of sensor means, which are responsive to the instantaneous ambient conditions and operating parameters, a beam splitter, which is disposed in the path of said primary beam and arranged to divert from said primary beam a partial beam to measuring means, which comprise a diffraction grating and associated focusing optical means and are arranged to direct said partial beam onto photodetector means and to form on said photodetector means a light spot having a position and/or size depending on the instantaneous wavelength of said primary beam. The photodetector means serve to detect deviations of the light spot from a desired position, which is associated with the rated wavelength of said primary beam.

Abstract: A system for measuring lengths or angles comprises a scale member provided with absolutely coded scale elements and incremental scale elements, a movable scanning unit generating position-dependent signals in response to the reading of the scale elements, and an evaluating unit for determining the absolute position of the scanning unit relative to the scale member in response to the position-dependent signals. The coded scale elements consist of different code words arranged according to a serial code and are read by a multiline detector which, in any position of the scanning unit relative to the scale member, reads at least an entire code word.

Abstract: A length measuring system comprises an elongate scale member adapted to be scanned for generating measured-length signals, a tubular scale member carrier defining an internal cavity housing the scale member and including a mounting wall, a connection of the scale member to the scale member carrier, the connection permitting a longitudinal movement of the scale member relative to the scale member carrier, and end blocks rigidly connected to the scale member carrier at both ends thereof, the end blocks defining recesses and having opposite sides.

Abstract: A tubular protective carrier housing for a length measuring system encased in the carrier housing, the housing having a longitudinal axis and comprising two end parts extending from respective sides of a center part, and fastening devices at the center and end parts for affixing the carrier housing to an object, the housing and the object being subject to thermal expansion. To simplify the structure, the carrier housing itself comprises a length equalizing element at the center part for compensating for differences in the thermal expansion of the housing and object.

Abstract: In a photoelectric position detector a scanning movement of a scanning phase grating relative to a scale member which is provided with a reflective phase grating is detected, light emitted by at least one light source is diffracted by the scanning grating and as it is reflected by the scale member and then again by the scanning grating to form an interference pattern and only groups belonging to said interference pattern and being of a predetermined diffraction order are detected by respective photodetectors and are converted by them to phase-displaced photodetector signals, which are cyclically changed as the scanning grating is moved relative to the scale member.

Abstract: A length measuring apparatus comprises a measuring device for detecting the position of a marker along a measuring path. The measuring device and the marker are encapsulated in a hermetically sealed housing. A follow-up device is provided for moving the marker to a predetermined position of registration relative to a detectable point, which is disposed outside the housing and is movable along a path which is parallel to and laterally aligned with the measuring path. The follow-up device comprises a device for establishing a non-contacting link between the detectable point and the marker. To provide such an apparatus which has a relatively simple design and a low susceptibility to disturbance and can achieve a high accuracy of measurement. The apparatus comprises a strip that is trained around reversing end pulleys and has a course that extends along the measuring path. The marker is carried by the course.

Abstract: The angle encoder comprises a transmitter disk, which is provided with two circular measuring scales, preferably incremental measuring scales. A scanning unit is associated with each of said measuring scales and during a rotation of said disk relative to said scanning head is adapted to scan said scale with reflected light and to optoelectronically generate measured-value signals, such as control signals in response to said scanning. To minimize the effect of a radial runout on the accuracy of the measurement and to permit a providing of the measuring scales on the transmitter disk by a copying process, the transmitter disk has at least one frustoconical outside surface, which is centered on the axis of rotation and is provided with the measuring scales. A process of manufacturing the transmitter disk is also described.

Abstract: In an incremental measuring system a measuring scale provided on a scale member is scanned, periodic, basically sinusoidal analog measured-value signals are generated as a result of said scanning, and digital countable signals, which depend on the direction of the scanning movement, are derived from said analog measured-value signals and are delivered to evaluating means, such as indicating or control means. Electronic means are provided for correcting errors consisting at least of defects of the scale or of the positioning of the scale member in accordance with a stored or predetermined correction program.

Abstract: An incremental length measuring system comprises a scale member, which is provided with a measuring scale, a scanning unit having scanning elements for scanning the scale and for generating measured-value signals in response to the scanning of the scale, and an analyzing unit for analyzing the measured-value signals. The scale member comprises a reference track, which is parallel to the measuring scale and provided with a plurality of selectable reference marks associated with respective reference points. The scanning unit comprises a plurality of scanning elements associated with respective ones of the reference marks. A selector switch is provided, which is movable in unison with the scanning unit and is operable by permanent magnet devices, which are associated with any of the reference marks when it has been selected and are contained in a protective housing that contains the scale member and the scanning unit.

Abstract: A protective housing for accommodating a scale member and a longitudinally movable scanning unit of a length measuring system comprises a housing tube, which is adapted to support the scale member and preferably has a basically rectangular cross-section and in one narrow side wall is formed with a slot, which is adapted to receive an actuating member, which is adapted to be coupled to the scanning unit, and which housing tube is adapted to be closed at both ends by end closures, which are adapted to hold the housing in position and protrude beyond the ends of the housing tube.

Abstract: In the operation of an incremental measuring system, a measuring scale is scanned for generating periodic sinusoidal, analog measured-value signals. Digital countable signals are derived from the measured-value signals in conjunction with an electronic subdivision of the scale and are delivered to an electronic evaluating unit. Each countable signal is associated with a certain phase angle of the measured-value signals.

Abstract: A scale member is provided with a scale, which can be optoelectronically scanned. In association with that scale, a scanning unit is provided, which comprises scanning sets for generating measured-value signals, and an evaluating unit is provided for deriving digital countable signals from said measured-value signals. A reference track comprising a plurality of reference marks is provided on the scale member and is parallel to the scale and the scanning unit comprises scanning sets for scanning the reference track. A control circuit is provided, which permits a generation or delivery of reference pulses only in response to the scanning of selected ones of the reference marks. To permit such selection, the scale member is provided with a control track, which can be scanned by the same method as the scale and the reference marks and which has a signal-generating characteristic which varies along the scale so that a signals have different levels are generated by an associated scanning set.

Abstract: The incremental measuring system comprises a scale member with an incremental scale and a scanning unit comprising scanning sets for generating analog measured-value signals in response to the scanning of the scale. The system also comprises an evaluating unit for deriving digital countable signals from the analog measured-value signals and for generating a reference pulse. At least one pair of reference marks are spaced along the scale on a carrier releasably fixed to the scale member. The scanning unit comprises a reference mark scanning set to scan the reference marks and connected to the evaluating unit. A reference point which registers with a selected increment of the scale is disposed on the carrier between the reference marks of the pair and can be defined by the distances from the reference point to the reference marks, and these distances are stored in a memory.

Abstract: An incremental measuring system comprises a scale member provided in one track with a measuring scale, and an optoelectronic scanning unit for generating measured-valve signals in response to a scanning of the scale. The scale member is provided in an additional track with two or more reference marks and the scanning unit is operable to scan the reference marks and to generate reference signals in response to the scanning of the additional track at one or more selectable reference points provided with such reference marks. The scale member and the scanning unit are encapsulated in an enclosure, which is formed with a slot, which is covered by a seal. An actuating member for the scanning unit extends through the slot past the seal. Covers for covering at least part of the reference marks are provided and are adapted to be inserted and/or removed into and from the enclosure or shifted along the tracks by a positioning member, which extend through apertures formed in the enclosure.

Abstract: The length measuring system comprises a scale member provided with a scale and a scanning unit, which is movable along the scale and is guided by the scale member or by separate tracks, which are parallel to the scale and is coupled to an actuating member by a backlashless coupling. The two coupling elements of the coupling cross each other and are in point contact with each other and having engaging surfaces which are centered on axes which are normal to the longitudinal direction of the scale member. A backlash of the coupling is prevented by a permanent magnetic biasing set, which comprises parts which are respectively connected to the actuating member and to the scanning unit and consist of two permanent magnets or of a permanent magnet and an armature.

Abstract: A method of digitally measuring displacement increments in which, for the relative displacement of a scanner and a scale having regularly spaced graduations each defining an increment of displacement, correction values and the signals are stored at respective addresses corresponding to the relative displacement and respective locations on the scale, only where the correction exceeds a predetermined threshold value. During the measurement, the measured values, which can correspond to each graduation and to interpolation values between each graduation and the next graduation to be scanned, are corrected with the corrected value addressed as each location is reached.

Abstract: A scanning unit is movable relative to a scale member and is connected to a fiber optical system for illuminating a reading unit with light that has been emitted by at least one light source and transmitted by the fiber optical system to the scale member. The reading unit is connected by a fiber optical system to the scanning unit and comprises optoelectronic receivers for converting the optical signals to electric signals. It is desired to use basically the same reading and illuminating units with different scale members and to use fiber optical systems also with coding scales and high-accuracy incremental scales. At least the reading fiber optical system which connects the optoelectronic receivers to the scanning unit consists of an image-transmitting, directive fiber optical system, which has a receiving area facing the scale member. Reading aids are disposed between the opposite end of said reading fiber optical system and the optoelectronic receivers.

Abstract: A non-contacting measuring apparatus for measuring a displacement in dependence on the incidence of a laser beam on a laser beam detector, e.g., for determining dimensions, the position or the spacing of objects, comprises a scanning unit for moving a laser beam, which has been emitted by a laser and projected across a measuring area from one edge thereof, and a receiver, which is disposed on the other side of the measuring area and arranged to receive said laser beam. Said receiver comprises a detector for generating an output signal in response to the incidence and nonincidence of said laser beam on said detector. A measuring circuit is responsive to said output signal.

Abstract: The linear incremental measuring system comprises an incremental scale, a scanning unit for generating two analog signals, which are displaced in phase in a direction depending on the direction of the scanning movement, and a processor for generating digital signals from the analog signals and for delivering said digital signals to a bidirectional counter, which is used to control a display device and/or a control device. In order to detect in a simple manner the velocity of the scanning movement relative to the scale and to generate a voltage that is proportional to that velocity and can be used to control a machine, digital signals derived from the analog signals are delivered to a digital-to-analog conversion circuit, which delivers an analog voltage that is proportional to the velocity of the scanning movement and has a polarity that is dependent on the direction of that movement.