Electronic watch

Details Electronic watch Electronic watch

2000-02-24

2003-02-04

Miska, Vit (Department: 2841)

Horology: time measuring systems or devices

With calendar indicator

C368S160000, C368S157000, C368S030000, C310S323170

Reexamination Certificate

active

06515941

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electronic watch and, more particularly, to an electronic watch which can be small-sized even with a calendar indicating function.
2. Related Art
FIG. 17
is a top plan view showing one example of the electronic watch of the prior art. This electronic watch
900
having an auto-calendar function, which is provided in addition to a time indicating stepping motor
901
with a stepping motor
902
for a calendar indicating mechanism so that it can be freed from the trouble of correcting the date at the end of a month by driving the calendar portion independently of the time indicating portion. The stepping motor
902
is composed of a coil
921
, a stator
922
and a rotor
923
, which is provided with a reduction gear mechanism
904
for transmitting a rotating torque to a date ring
903
. The rotor
923
is equipped with a pinion
924
for transmitting a rotating torque to the reduction gear mechanism (or a reduction gear train). This reduction gear mechanism
904
is composed of a first intermediate date ring
941
and a second intermediate date gear
942
.
The calendar indication mechanism is composed of the date ring
903
having an inner circumference toothed at
932
, and a date gear
931
engaging with the second intermediate date gear
942
for transmitting the rotating torque to the date ring
903
. This date ring
903
is rotatably arranged on the (not-shown) calendar back plate.
The stepping motor
902
is electrically connected with a circuit block attached to the back of a base plate
905
, so that it is rotated with drive pulses coming from an electronic circuit. The rotations of the stepping motor
902
are transmitted to the date gear
931
through the pinion
924
of the rotor
923
, the first intermediate date ring
941
and the second intermediate date ring
942
.
The date gear
931
engages with the teeth
932
so that the date ring
903
is rotated by the rotations of the date gear
931
.
Since the torque to be generated by the stepping motor
902
is seriously low, however, the multistage reduction gear mechanism
904
is necessary for rotating the date ring
903
. This has raised a problem that it is difficult to reduce the size of the electronic watch
900
which has multiple functions to indicate a variety of data in addition to the time information such as the auto calendar function.
Since the stepping motor
902
belongs to an electromagnetic conversion mechanism, on the other hand, it may exert an influence on the time indicating stepping motor
901
. This makes it necessary to retain a distance between the two stepping motors
901
and
902
. This necessity has made it impossible to reduce the size of the multi-function electronic watch
900
.
SUMMARY OF THE INVENTION
Thus, the invention has been conceived in view of the foregoing description and has an object to provide an electronic watch which can be small-sized even with an additional function such as the calendar mechanism.
In order to achieve the above-specified object, according to the invention, there is provided an electronic watch wherein a piezoelectric actuator to be displaced by applying a voltage thereto is arranged in the vicinity of a portion of a second indication member for indicating data other than the time and is brought into press contact with the second indication member to drive the same directly.
When an alternating voltage or a pulsating voltage is applied to the piezoelectric element composing the piezoelectric actuator, the piezoelectric element is elongated and contracted by the piezoelectric effect so that a displacement corresponding to the applied voltage is established in the piezoelectric actuator. With the construction in which the piezoelectric actuator is brought into press contact with the second indication member, the displacement of the piezoelectric actuator causes a driving force of the second indication member through a friction. As the second indication member, there can be enumerated a date ring for indicating the date information, a chronograph and a moon face, for example. The piezoelectric actuator generates a higher force per unit volume than that of the stepping motor so that it can be made smaller in volume than the stepping motor and can be confined in the vicinity of a portion of the second indication member. Moreover, the high force makes the reduction gear mechanism unnecessary so that the electronic watch can be small-sized. Without the electromagnetic conversion mechanism, on the other hand, the piezoelectric actuator is not adversely affected by the time indicating stepping motor. Since the piezoelectric actuator need not be arranged apart from the time indicating stepping motor, therefore, it is possible to obtain an effect that the degree of freedom for designing the electronic watch is drastically enhanced. Here, similar operations and effects can be achieved in the invention, as will be described in the following.
According to the invention, on the other hand, there is provided an electronic watch wherein a second indication member for indicating data other than the time is disposed to confront a base plate, and wherein a piezoelectric actuator for establishing a displacement when a voltage is applied thereto is arranged between the base plate and the second indication member and is brought into press contact with the second indication member to drive the same directly.
The piezoelectric actuator is arranged between the second indication member such as the date ring and the base plate and is directly driven with the laminated structure in which it is is brought into press contact with the second indication member. As a result, the planar space can be drastically reduced while eliminating the reduction gear train, so that the multi-function electronic watch can be remarkably small-sized.
According to the invention, on the other hand, there is provided an electronic watch wherein a second indication member for indicating data other than the time is disposed to confront a base plate, wherein the second indication member is provided with a beam portion on its face confronting the base plate, and wherein a piezoelectric actuator for establishing a displacement by applying an electric signal to a piezoelectric element is brought into press contact with the side face of the beam portion thereby to drive the second indication member directly.
The construction is made such that the second indication member such as the date ring is provided with the beam portion on its face confronting the base plate and such that the piezoelectric actuator is brought into press contact with the side face of the beam portion. As a result, the mechanism for forcing the piezoelectric actuator to contact with the side face of the beam portion can be planarly arranged so that the electronic watch can be small-sized and thinned. With this construction, on the other hand, the contacting state of the piezoelectric actuator and the second indication member can be stabilized to provide another effect that the drive of the second indication member can be excellently stabilized. The method of applying the piezoelectric actuator to the beam portion maybe exemplified by urging the piezoelectric actuator directly or by pushing the piezoelectric actuator from the face opposed to the contacting face. Another effect is that a high degree of freedom for the design can be achieved to reduce the size of the electronic watch effectively.
On the other hand, an electronic watch according to the invention is characterized in that the piezoelectric actuator is a rectangular piezoelectric oscillator including: a first rectangular piezoelectric element having on its surface four divided electrodes, two individuals of which are electrically shorted to construct two sets of electrode groups; and a second rectangular piezoelectric element having an electrode extending substantially all over the surface, and in that the rectangular piezoelectric oscillator is caused to generate bending oscillations and long

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