Incremental length measuring system
First Claim
1. In an incremental length measuring system comprisingan elongate scale member provided with a measuring scale extending along said scale member and with a reference track, which extends along said scale and is provided with a plurality of longitudinally spaced apart reference marks defining respective reference points on said scale,a scanning unit, which is mounted to be movable along said scale member and comprises first scanning means for scanning said scale and for generating measured-value signals in response to the scanning of said scale and second scanning means, which are adapted to scan said reference track and to generate a reference pulse in response to the scanning of each of said reference marks,a protective housing, which contains said scale member and said scanning unit,analyzing means connected to receive said measured-value signals and said reference pulses from said scanning unit and adapted to derive data from said signals under the control of said reference pulses, andselecting means for arbitrarily selecting any of said reference marks and for permitting a delivery of a reference pulse to said analyzing means only in response to the scanning of a selected one of said reference marks by said second scanning means, which selecting means comprise a selector switch, which is arranged to move along said scale member in unison with said scanning unit along a predetermined path and is operable to permit the delivery of such a reference pulse to said analyzing means, and permanent magnet means, which are positioned in said housing in association with any selected one of said reference marks and arranged to operate said switch in conjunction with the scanning of said selected reference mark so as to permit the delivery of such reference pulse in response to such scanning,the improvement residing in thatsaid permanent magnet means comprise a plurality of permanent magnets, each of which is associated with one of said reference marks and is mounted in said hosung to be individually movable from the outside of said housing between an inactive position, in which said permanent magnet is unable to operate said switch in conjunction with the scanning of the associated reference mark, and an active position, in which said permanent magnet is arranged to operate said switch in conjunction with the scanning of the associated reference mark.
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Accused Products
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. The selector switch is operable to permit a generation or delivery of a reference pulse in response to the scanning of a reference mark by the scanning unit only when the reference mark has been selected. To facilitate the selection of a desired reference mark, a permanent magnet which is mounted within the protective housing is permanently associated with each selectable reference mark and each of the permanent magnets is selectively movable between an inactive position and an active position, in which the permanent magnet is arranged to actuate the selector switch.
37 Citations
22 Claims
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1. In an incremental length measuring system comprising
an elongate scale member provided with a measuring scale extending along said scale member and with a reference track, which extends along said scale and is provided with a plurality of longitudinally spaced apart reference marks defining respective reference points on said scale, a scanning unit, which is mounted to be movable along said scale member and comprises first scanning means for scanning said scale and for generating measured-value signals in response to the scanning of said scale and second scanning means, which are adapted to scan said reference track and to generate a reference pulse in response to the scanning of each of said reference marks, a protective housing, which contains said scale member and said scanning unit, analyzing means connected to receive said measured-value signals and said reference pulses from said scanning unit and adapted to derive data from said signals under the control of said reference pulses, and selecting means for arbitrarily selecting any of said reference marks and for permitting a delivery of a reference pulse to said analyzing means only in response to the scanning of a selected one of said reference marks by said second scanning means, which selecting means comprise a selector switch, which is arranged to move along said scale member in unison with said scanning unit along a predetermined path and is operable to permit the delivery of such a reference pulse to said analyzing means, and permanent magnet means, which are positioned in said housing in association with any selected one of said reference marks and arranged to operate said switch in conjunction with the scanning of said selected reference mark so as to permit the delivery of such reference pulse in response to such scanning, the improvement residing in that said permanent magnet means comprise a plurality of permanent magnets, each of which is associated with one of said reference marks and is mounted in said hosung to be individually movable from the outside of said housing between an inactive position, in which said permanent magnet is unable to operate said switch in conjunction with the scanning of the associated reference mark, and an active position, in which said permanent magnet is arranged to operate said switch in conjunction with the scanning of the associated reference mark.
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22. In an incremental length measuring system comprising
an elongate scale member provided with a measuring scale extending along said scale member and with a reference track, which extends along said scale and is provided with a plurality of longitudinally spaced apart reference marks defining respective reference points on said scale, a scanning unit, which is mounted to be movable along said scale member and comprises first scanning means for scanning said scale and for generating measured-value signals in response to the scanning of said scale and second scanning means, which are adapted to scan said reference track and to generate a reference pulse in response to the scanning of each of said reference marks, a protective housing, which contains said scale member and said scanning unit, analyzing means connected to receive said measured-value signals and said reference pulses from said scanning unit and adapted to derive data from said signals under the control of said reference pulses, and selecting means for arbitrarily selecting any of said reference marks and for permitting a delivery of a reference pulse to said analyzing means only in response to the scanning of a selected one of said reference marks by said second scanning means, which selecting means comprise selector switching means, which are operable to permit the delivery of such a reference pulse to said analyzing means in response to the scanning of one of said reference marks only when said reference mark has been selected, the improvement residing in that a plurality of first coupling elements are provided, which are fixed against a movement along said scale member and associated with respective ones of said reference marks, each of said first coupling elements is adapted to be independently selectively activated, a second coupling element is provided, which is coupled to said scanning unit to move in unison therewith and is adapted so to cooperate with each of said first coupling elements when it is activated that in conjunction with the scanning of a selected reference mark by said scanning unit said selector switching means are activated to permit the delivery of such reference pulse to said analyzing means in response to the scanning of said selected reference mark.
Specification