Seiko Instruments Inc

Akihiko Inada

Shigeo Suzuki

Masayuki Kawata

Takayuki Satodate

Kenichi Nakajima

Mitsuru Ishii

Eriko Takakuwa

Yuko Sasaki

Akihiro Matouge

Yoshio Koyama

Electronic timepiece

An electronic timepiece has a wheel train mounted for undergoing rotation and a transmission wheel for undergoing rotation in accordance with rotation of the wheel train. A contact point spring is connected to the transmission wheel for rotation therewith. The contact point spring extends substantially linearly through a rotational center of the transmission wheel. First and second detection patterns contact the contact point spring during rotation of the transmission wheel to generate a rotational position detecting signal corresponding to a rotational position of the transmission wheel. The first and second detection patterns are disposed at an angle of substantially 180 degree relative to the rotational center of the transmission wheel.

Electronic timepiece having transmission wheel rotational position detecting apparatus

A calendar electronic timepiece comprises a signal generating circuit for generating a date signal, a driving circuit for outputting a driving signal in accordance with the date signal generated by the signal generating circuit, and an ultrasonic motor driven by the driving signal outputted by the driving circuit. The ultrasonic motor is comprised of a piezoelectric vibrator having an electrode pattern and being driven by the driving signal outputted from the driving circuit to undergo expansion and contraction movement, a vibrating member connected to the piezoelectric vibrator and vibrationally driven by expansion and contraction movement of the piezoelectric vibrator, and a date dial disposed on the vibrating member to be frictionally driven by expansion and contraction movement of the piezoelectric vibrator.

Calendar electronic timepiece

To provide an electronic timepiece enabling reliable detection of a state of rotation of an indication wheel such as a date dial. An ultrasonic motor 1130 has an ultrasonic rotor pinion 1134b. A date dial 1120 is disposed on a main plate 1102 in such a way as to rotate relative thereto. The ultrasonic rotor pinion 1134b is meshed with an intermediate date driving gear wheel 1142a. A date driving wheel 1150 is rotatably disposed on the main plate 1102. A date driving gear wheel 1150b is meshed with an intermediate date driving pinion 1142b. A date driving gear portion 1150b is meshed with a dial gear portion 1120a. A contact point spring 1160 is disposed on a spring guiding portion 1150d. The contact point spring 1160 rotates integrally with the date driving wheel 1150 through the rotation of the date driving wheel 1150. The state of rotation of the date driving wheel 1150 can be detected by contact of the contact point spring 1160 with the contact point pattern 1174.

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Chiba, Japan

Akihiko Inada