| 摘要 |
In this device, it is possible to adjust by means of a scale consisting of at least two segments (2, 2a) a measurement carriage (6) which has phototransistors (I, II) for the photoelectric scanning of an incremental graduation (3) of the scale, which control display devices for the measured length, control devices for taking account of the adjustment direction of the carriage (6) for the counter sign being provided. In order to simplify the composition of the segments (2, 2a), and to ensure that the gap width (A) between two segments (2, 2a) of the scale does not influence the measurement accuracy, two groups (I, II) of phototransistors for scanning the scale are arranged on the measurement carriage (6) at a distance from one another that is kept larger than the gap width (A), provision being made of a changeover switch which in each case connects only one of these groups (I or II) to the counting mechanism and also the control device for the sign. The changeover switch can be operated by control devices (4, 5, 7, 8) assigned to the joint regions of the scale segments (2, 2a) when each joint region is crossed over by the carriage (6), and alternately switches from the scanning group (I or II) reaching and crossing the joint region to the respective other scanning group (II or I). <IMAGE>
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