Horology: time measuring systems or devices – With calendar indicator
Reexamination Certificate
2000-05-30
2003-06-24
Miska, Vit (Department: 2841)
Horology: time measuring systems or devices
With calendar indicator
C368S184000, C368S037000, C368S038000
Reexamination Certificate
active
06584040
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electronic timepiece having a transmission wheel rotation position detecting unit which detects the position in the rotation direction of a transmission wheel of the electronic timepiece contained in a wheel train thereof such as an obverse wheel train or calendar wheel train.
2. Description of the Prior Art
In a conventional electronic timepiece, as illustrated in
FIG. 38
, a part of an obverse wheel train
930
, e.g., a 24-hour contact point
932
for detecting a rotational position of the obverse wheel train
930
is provided on an hour wheel. When the 24-hour contact point
932
detects the position corresponding to the time of twelve o'clock at night, according to a detection signal output from the 24-hour contact point
932
a circuit block
934
rotates a date driving motor
936
. Due to the rotation of the date driving motor
936
, a date dial
912
is rotated through a reduction wheel train
938
. This makes it possible to change the display of the date.
In the above-described conventional electronic timepiece, in a region near to an outer-peripheral portion of a gear portion of the hour wheel there was provided a conduction pin. And, it was arranged that when the hour wheel rotated, the conduction pin moved a contact point spring so as to cause this contact point to contact with a contact point pattern of the circuit block, and that, when the hour wheel further rotated, the conduction pin was moved away from the contact point spring with the result that the contact point spring was moved away from the contact point pattern of the circuit block. Namely, the contact point spring corresponds to the 24-hour contact point
932
and it was arranged that when the contact point spring contacted with the contact point pattern of the circuit block, the position corresponding to the time of twelve o'clock at night was detected.
Also, in a structure wherein the date driving wheel was rotated through the rotation of the intermediate date driving wheel by the rotation of the date driving motor and the date dial was rotated by the rotation of the date driving wheel, the tooth configuration of the respective gears of the intermediate date driving wheel, date driving wheel and date dial was constituted by a circular arc tooth configuration that includes one or more circular arc portions.
Accordingly, when an external force such as an impact had been applied to the date dial, the rotation of the date dial was stopped by only the index torque of the date driving motor.
However, in the conventional electronic timepiece, there were the problems which follow.
(1) Since the contact point spring was formed of material which was easy to flex, the portion of the contact point spring which contacted with the contact point pattern was difficult to position.
(2) In order to dispose the contact point spring having a sufficient spring length, a significantly large space was needed in the electronic timepiece.
(3) When the portion of the contact point spring which contacts with the contact point pattern is disposed at a position which is farther away from the contact point pattern than necessary, even when the hour wheel rotates, the contact point spring cannot be contacted with the contact point pattern of the circuit block by the conduction pin, with the result that time display or calendar display becomes unable to be accurately made.
(4) When the portion of the contact point spring which contacts with the contact point pattern is disposed at a position which is nearer to the contact point pattern than necessary, when the hour wheel has rotated, the pressure of the contact point spring applied to the conduction pin becomes high, with the result that there is the likelihood that any inconvenience will occur in the operation of the electronic timepiece or the electronic timepiece will inconveniently stop.
(5) The structure of the hour wheel becomes complicated with the result that it becomes necessary to use the contact point spring having a sufficient spring length.
(6) In the conventional calendar equipped electronic timepiece provided at a part of the obverse wheel train with the 24-hour contact point for detecting the rotation position of the obverse wheel train, since a number of wheel trains were disposed between the obverse wheel train and the date dial, it was difficult to achieve an accurate positional coincidence of the date dial due to the backlashes between two adjacent ones of the respective wheel trains.
(7) It was difficult to enhance the precision with which the position in the rotation direction of the hour wheel was detected.
(8) There was the possibility that when an external force such as an impact had been applied to the electronic timepiece, the indication wheel or date dial would rotate. In order to prevent the resulting positional displacement of the date dial, it was needed to increase the index torque of the motor (the stationary force: the torque that resists the rotation when at rest). However, when increasing the index torque of the motor, it resulted that the electric power needed when driving the motor also became increased and as a result the battery life of the electronic timepiece was decreased.
SUMMARY OF THE INVENTION
In view of the above, an object of the present invention is to provide an electronic timepiece having a transmission wheel rotation position detecting unit which, in order to solve the above-described conventional problems, detects accurately the position in the rotation direction of the transmission wheel.
Also, another object of the present invention is to provide a small sized electronic timepiece having a transmission wheel rotation position detecting unit.
Further, still another object of the present invention is to provide a small sized and thin type electronic timepiece having a transmission wheel rotation position detecting unit. And,
Further, a further object of the present invention is to provide an electronic timepiece having a transmission wheel rotation position detecting unit whose contact point has a high durability performance.
Also, a yet further object of the present invention is to provide an electronic timepiece which is equipped with a small-sized simplified date driving mechanism and indication wheel detecting mechanism.
Also, a yet further object of the present invention is to provide an electronic timepiece in which even when an external force such as an impact has been applied to the electronic timepiece there is no possibility that the indication wheel or date dial will rotate.
In order to solve the problems, the present invention has been constructed such that an electronic timepiece according thereto comprises a transmission wheel rotating according to the rotation of a wheel train contained in the electronic timepiece, a contact point spring fixed to the transmission wheel and rotating integrally with the transmission wheel and having a conductivity, a detection pattern which is provided on a printed circuit board and, when the contact point spring rotates, can contact with the contact point spring, and a control circuit which inputs a rotational position detection signal for detecting a circumferential position of the rotation of the transmission wheel which, when the contact point spring has contacted with the detection pattern, is output from the detection pattern.
By this construction, the transmission wheel rotation position can be detected using small-sized and simple parts.
Also, in the electronic timepiece according to the present invention, preferably, the detection pattern includes two detection patterns which, when the contact point spring rotates, can simultaneously contact with the contact point spring, and the control circuit which is a control circuit which inputs rotational position detection signals each for detecting the circumferential position of the rotation of the transmission wheel which, when the two detection patterns have been conducted to each other by the contact point spring, are respectivel
Inada Akihiko
Ishii Mitsuru
Kawata Masayuki
Koyama Yoshio
Matouge Akihiro
Goodwin Jeanne-Marguerite
Miska Vit
Seiko Instruments Inc.
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