Hand position detecting device and apparatus including the device

Abstract

The invention provides a hand position detecting device which detects the rotational positions of seconds hands precisely and reliably. The detection unit (13) detects light passing through apertures (21, 28 and 29) provided in a seconds wheel (20), a center wheel (25) and an hour wheel (27), respectively, which rotate on the same axis. The apertures (21) in the seconds wheel (20) include a circular aperture (21a) provided at a reference position therein, and two apertures (21b) and (21c) provided separated by corresponding arcuate apertures (21d and 21e) of different lengths from the aperture (21a) on its opposite sides, respectively. By counting the number of light non-detection events the detection unit encounters due to the light blocking area (21e) covering the detection unit (13), the rotational position of the seconds wheel (20) is detected accurately and securely.

Description

technical field [0001] The present invention relates to a hand position detection device for detecting the pointer running positions of hands such as a second hand, a minute hand, and an hour hand. Background technique [0002] Conventionally, there is known a needle position detection device for an analog timepiece disclosed in JP-A-2000-162336. In this hand position detecting device of an analog timepiece, a first drive system is provided for moving the second hand by a second hand wheel rotated by the rotation of the first drive motor; The second drive system that rotates the minute wheel and the hour wheel separately for the minute hand and the hour hand; and the second wheel, the minute wheel, and the hour wheel of the first and second drive systems rotate in a state of overlapping on the same axis , the first to third light transmission holes respectively provided on the second wheel, the minute wheel, and the hour wheel are optically detected by a light-emitting elem...

AI Technical Summary

Problems solved by technology

Therefore, when rotating the second hand wheel to perform position detection, if the second hand wheel is rotated at a high speed, there is a danger that the 11 photodetection holes cannot be reliably detected, and there is a problem that the position detection speed during high-speed operation is limited.

[0007] In addition, in the latter first driving system, since it is equipped with: a light detection hole provided at the reference position of the second hand wheel; The structure of the pair of cutout holes increases the permissible amount of light transmitted through the pair of cutout holes, and can detect the position of the second hand wheel at high speed rotation. However, the light detection hole of the fifth wheel is configured to correspond to the detection part When passing through one notch hole of the second hand wheel so that the light-shielding portion of the second hand wheel corresponds to the light detection hole of the fifth wheel, and then a part of the other notch hole of the second hand wheel corresponds so that there is light detection through the detection portion, Since the second hand points to the hour, it is judged that the second hand is pointing to the hour no matter which part of the other notch hole corresponds to the detection unit, so there is a problem that the rotation position of the second hand wheel cannot be accurately specified.

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