Kabushiki Kaisha Daini Seikosha

Hiromasa Nakanishi

Masataka Ikenishi

Shozo Kushida

Joichi Miyazaki

Makoto Ueda

Masaharu Shida

An electronic timepiece having a stepping motor and a drive circuit responsive to a control signal for applying electrical drive pulses having polarities determined by the control signal for rotating the rotor of the stepping motor. The control circuit normally operates in a mode for applying a control signal to the drive circuit effective to control the drive circuit to apply alternate polarity electrical drive pulses to rotate the stepping motor rotor in a normal direction. Resetting circuitry is operable for correcting the time kept by the timepiece. A detecting circuit detects whether the stepping motor rotor is in a position to be rotated by a forthcoming drive pulse after resetting. If the stepping motor rotor is not in a position for rotation a detection circuit signal is applied to the control circuit so that the control signal controls the drive circuit to apply an electrical pulse effective to rotate the stepping motor rotor after resetting. Consequently, after resetting the immediately forthcoming drive pulse will have a polarity effective to rotate the stepping motor rotor and no time will be lost.

Electronic watch

In an electronic watch a non-operation detecting circuit detects the non-operative condition of the stepping motor of the watch and produces a non-operation signal each time the stepping motor fails to operate in response to the standard pulse which drives the same. A counter counts the number of non-operation signals and stores the count for later use. A rotation detecting circuit detects the resumption of operation of the stepping motor in response to the standard pulse from the non-operative condition and a quick feed control circuit quickly advances the stepping motor in response to an input from the rotation detection circuit by thereafter supplying, instead of the standard pulses, the quick feed pulses to the drive circuit for the motor equal in number to the number of the non-operation signals counted in the counter. In this way the corrected time will be displayed by the watch even after being rendered inoperative as a result of an external condition such as low temperature or a high strength DC magnetic field.

An electronic watch movement including a base plate having a pair of opposite major surfaces. A calendar ring is disposed confronting a first of the major surfaces, and a circuit board is disposed confronting the second major surface. The calendar ring has a narrow central annular portion, a wide peripheral skirt portion circumscribing the narrow central annular portion and a circular step portion extending between the narrow central annular portion and the wide peripheral skirt portion. The skirt portion of the calendar ring is spaced further from the base plate then the central annular portion of the calendar ring. The base plate has openings therethrough opposite the skirt portion of the calendar ring, and electronic watch components are mounted on the major surface of the circuit board and extend through the openings through the base plate beyond the narrow central annular portion of the calendar ring toward the wide peripheral skirt portion of the calendar ring. The electronic watch components are oriented to minimize the thickness of the electronic watch movement.

A calender mechanism comprising a cannon wheel having a gear wheel portion and a cylindrical portion extending axially from the gear wheel portion, a day star wheel mounted for rotation on a cylindrical portion of the cannon wheel, and a positioning plate. The day star wheel has an outer diameter less than that of the gear wheel portion of the cannon wheel, and the positioning plate is positioned to partially overlie the outer peripheral portion of the gear wheel portion for preventing the cannon wheel from traveling axially toward the day star wheel. The portion of the positioning plate overlying the outer peripheral portion of the cannon wheel does not extend between the day star wheel and the gear wheel portion of the cannon wheel.

Growing community of inventors

Tokyo, Japan

Hiromasa Nakanishi