Citizen Watch Company, Ltd.

Takayasu Machida

Fumio Nakajima

Kenji Yamada

Takanori Nanya

Akira Nikaido

Shigeyuki Takahashi

Kazuo Suzuki

Takeaki Shimanouchi

Yasushi Nomura

Minoru Watanabe

Takashi Toida

Kazunari Kume

Mitsuo Onda

Yasuhisa Hirosawa

Shigeru Morokawa

Munetaka Tamaru

Seiichi Nakamura

Hideshi Ohno

Hisao Wakabayashi

Fumio Kanno

Yoshiyuki Ohishi

Kunio Suganuma

Hiroshi Mabuchi

Hiroshi Kurafuji

Churyo Seki

A stator ( ) is made up by bonding a first stator part ( ) made of a high-permeability material to a second stator part ( ) made of a high-permeability material respectively by welding through the intermediary of connections ( ) made of a low-permeability material or a nonmagnetic material, interposed therebetween. Paired recesses ( ) serving as holding torque setting means for holding a rotor ( ) by a magnetic action are formed on the inner periphery of a rotor hole ( ) defined inside the stator ( ) at the position forming an initial phase angle (&thgr; ). A field coil ( ) for excitation is magnetically bonded to opposite ends of the stator ( ), thereby forming a two-pole step motor for a timepiece.

Two-pole step motor for timepiece

A stator ( ) is made up by bonding a first stator part ( ) made of a high-permeability material to a second stator part ( ) made of a high-permeability material respectively by welding through the intermediary of connections ( ) made of a low-permeability material or a nonmagnetic material, interposed therebetween. Paired recesses ( ) serving as holding torque setting means for holding a rotor ( ) by a magnetic action are formed on the inner, periphery of a rotor hole ( ) defined inside the stator ( ) at the position forming an initial phase angle (&thgr; ). A field coil ( ) for excitation is magnetically bonded to opposite ends of the stator ( ), thereby forming a two-pole step motor for a timepiece

2-Pole stepper motor for timepiece

A pair of parallel rectangular windows are punched out in a thin sheet base material having the same thickness as that of a short hand part ( ) including a weight part ( ) of a second hand ( ) so as to form a hand forming part between the pair of windows and a part in the hand forming part forming a long hand part and a mounting part of a hand is pressed so as to form a thin wall part. Then, the second hand in a final shape is punched out from the base material so that a long hand part ( ) and a mounting part ( ) are formed with the thin wall part of the hand forming part and the short hand part ( ) is formed with an original thickness part. Consequently, the second hand for an analog electronic timepiece in which the weight part ( ) is provided on the short hand part ( ) can be easily and securely manufactured only by a press working.

Method of manufacturing hand for analog electronic timepiece

In an analog electronic timepiece in which the rotation of a rotor ( a) step motor ( ) is decelerated through train wheels before it is transmitted an hour hand ( ) and a minute hand ( ), the gravity center of a center wheel composed of a center wheel gear ( ), a center wheel pinion ( ), and a center wheel shaft ( ) to which the minute hand ( ) is mounted is displaced from the axis of the center wheel shaft ( ) to within an angle range of less than &plusmn;90&deg; with respect to the opposite direction to a direction in which a time indicating part ( a) of the minute hand ( ) extends so as to reduce a moment on the center wheel shaft ( ) caused by a combination of the minute hand ( ) and the center wheel. This makes it possible to prevent a hand-skip due to disturbance even if the value of holding energy of the step motor ( ) is reduced.

Analog electronic timepiece

The present invention provides a floppy disk drive which can removably receive a cartridge containing a floppy disk and which can travel a READ/WRITE head to the desired track on the floppy disk while rotating the floppy disk at a constant speed for effecting the desired read/write action under an electric-magnetic conversion. The drive is of a top-up type which includes a frame portion and a carrier which can be popped up from the frame portion. The frame portion includes a spindle motor for directly driving the floppy disk, a plurality of positioning pins for positioning the disk cartridge relative to the spindle motor, and a carriage carrying the READ/WRITE head for travelling the head to the desired track on the disk. The carrier is pivotably supported by the frame portion and adapted to receive the disk cartridge. The cartridge can be loaded into the lower portion of the carrier upon popping-up of the carrier. When the carrier is engaged by the frame, the cartridge is upwardly moved to a predetermined position within the carrier.

Floppy disk drive having a pivotally supporting cartridge carrier

A carriage device used for moving and positioning a magnetic head opposite prescribed tracks of a magnetic disk has the magnetic head mounted on a carriage which has linear motor mechanisms built integrally therein. The linear motor mechanisms incorporate coils secured to part of the carriage and permanent magnets secured aorund the coils. Guide rails serving to support the carriage within the range of the sliding motion of the coils are made of a magnetic substance.

Carriage device for moving and positioning magnetic head

The present invention provides a micro stepping motor for more accurately stepping and positioning a magnetic head in a magnetic disc system. The stepping motor has a permanent magnet type rotor and a stator encircling the rotor, the rotor having a plurality of pole teeth formed therein with a fine pitch and the stator also having a plurality of pole teeth formed therein with a fine pitch and disposed opposed to the pole teeth in the rotor, the stator pole teeth being divided into at least one pair of pole tooth groups which are out of phase relative to each other by an electrical angle of 180 degrees. A single common stator coil is provided to the pair of stator pole tooth groups. Thus, the stepping pitch of the rotor is determined by the pitch in the pole tooth groups, whereby the rotor can steppingly be driven with higher density even by the reduced number of stator coils. In addition, plural pairs of pole tooth groups can be formed such that at least two pairs of pole tooth groups and the corresponding two stator coils will be provided to determine the stepping angle of the rotor optionally under the multi-excitation.

Micro stepping motor

In a circuit for driving a pulse motor of an electronic timepiece, the initial part or entirety of each drive pulse is modulated to form a group of high frequency pulses thereby reducing an initial surge of current while rotor of motor is still stationary. Modulation can be controlled according to load placed on motor to provide increased drive energy for heavy loading.

Drive system for pulse motor

In an electronic timepiece having a stepping motor which drives time indicating means, a system is provided for detecting an increase in the load torque on the stepping motor above a predetermined level. When such an increase is detected, the conditions for detection of the load on the stepping motor are changed, and thereafter drive pulses of increased power are applied to the stepping motor. When the increased load is removed, this is detected under the new set of detection conditions, and a return to the original detection conditions is executed, with the drive pulse power being returned to the original level. Stability of control is thereby provided, together with immediate response to increased load on the stepping motor.

Drive control system for stepping motor

An electronic timepiece having a reversible stepping motor to actuate time-indicating hands to provide a time display, which comprises a driver circuit to produce driving current pulses composed of compound pulses appearing each time unit. A rotor of the stepping motor rotates a plurality of steps during each time unit to cause one of the time-indicating hands to advance through unequal intervals to provide a modulated display.

Electronic timepiece

An electronic timepiece including a battery, a drive motor, a drive, a display, and electronic circuits for driving said motor. The motor is a pulse motor and comprises a core, coil, yoke and rotor. The rotor includes a worm gear having worm teeth which engage with a gear wheel. The teeth on the worm gear are arranged and configured such that the initial and final portions of each tooth which engage with the gear wheel are parallel to the plane of rotation of the rotor thereby preventing torque applied to the gear wheel from being transmitted to the rotor.

Motor and drive for a timepiece

An electro-mechanical transducer driver circuit for an electronic timepiece characterized in that the pulse width of a driving pulse which drives an electro-mechanical transducer is controlled in a step-wise manner by the induced voltage of a driving coil.

Driver circuit for electro-mechanical transducer

An electronic timepiece includes a reversible stepping motor to drive rotatable hands to provide a time display. In a first preferred embodiment, the electronic timepiece includes a circuit means to generate alternating current pulses having an increased pulse width or an increased amplitude to drive the stepping motor with an increased driving current during high speed time correction when a manually operable external control member is actuated during time correction. In a second preferred embodiment, the electronic timepiece comprises a clockwise correction switch, a counter-clockwise correction switch and circuit means for generating first and second alternating current pulses of first and second pulse widths at a predetermined frequency higher than normal driving pulses to drive a stepping motor in clockwise and counter-clockwise directions, respectively, to perform clockwise and counter-clockwise corrections when the clockwise and counter-clockwise correction switches are actuated during time corrections, respectively. The pulse width of the second alternating current pulses is selected to be smaller than that of the normal driving pulses.

A pulse motor for clockworks and the like in which the rotor comprises two spaced-apart permanent magnetic disks mounted upon a common shaft and rotatable with respect to a stator. The stator comprises a respective pair of magnetic poles in the plane of each disk, the poles of the pair being interconnected by a shank and a coil wound upon the respective shanks, the coils lying on opposite sides of the rotor. The coils can be excited independently to cause the respective pair of poles to magnetically cooperate with the respective disk and rotate the motor in the forward or the reverse sense.

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Iruma, Japan

Takayasu Machida