Horology: time measuring systems or devices – Chronological – With mechanical or electromechanical driven display
Reexamination Certificate
2000-08-21
2002-07-02
Roskoski, Bernard (Department: 2859)
Horology: time measuring systems or devices
Chronological
With mechanical or electromechanical driven display
C368S187000, C368S204000
Reexamination Certificate
active
06414908
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electronic clock and a pointer position detecting method, or more specifically to an electronic clock and a pointer position detecting method for obtaining a signal for making a specific action by detecting that a pointer has come to predetermined position.
2. Description of the prior Art
An electronic clock is arranged so as to make a specific action when a pointer comes to predetermined position. Examples of the specific action include sounding time, turning a calendar, adjusting the clock based on radio wave received from the outside, and so on. When time is to be sounded when a minute hand stands at twelve o'clock, the electronic clock outputs a time sounding signal to a circuit for sounding the time by detecting that the minute hand stands at twelve o'clock. That is, the position of the pointer must be detected in the electronic clock to make a specific action when the pointer comes to predetermined position.
As a prior art, there has been known a technology of detecting the pointer position by using a mechanical contact. In the technology of using the mechanical contact, a center wheel & pinion is provided with a projecting cam and a contact made of leaf spring facing to the center wheel & pinion. Because the contact is hooked by the cam every time when the center wheel & pinion makes a turn in a hour and oscillates between a pair of contact springs, it is judged that the minute hand has come to predetermined position (position indicating twelve o'clock for example) when the contact is hooked by the cam and a signal, e.g., a time sounding signal, for making a predetermined action is outputted.
Japanese Patent Laid-Open NoS. 55-82080 and 61-118483 and Japanese Utility Model Laid-Open No. 56-10883 have also disclosed technologies of optically detecting the pointer position. According to the technologies, gears in a wheel train is disposed so that at least a part thereof overlap each other, each gear is provided with a transparency which agrees at constant cycle, e.g., once in a hour, and a light emitting device and a light receiving device are disposed on an extension in the axial direction at the position where the respective transparencies agree. The respective transparencies agree when the light receiving device receives light from the light emitting device. Then, the clock judges that the pointer has come to predetermined position, e.g., position indicating twelve o'clock, and outputs a signal, e.g., a time sounding signal, for making a predetermined operation.
However, the method of detecting the pointer position by using the mechanical contact has had a problem that the precision of detection drops due to deterioration of the contact and the contact springs. It also has had a problem that torque of a motor must be increased because the contact becomes a rotational resistance of the wheel train, thus increasing power consumption.
Meanwhile, the method of optically detecting the pointer position has had problems that it is costly because it requires the light emitting device and the light receiving device and that it is difficult to compact the clock. It also has had a problem that its structure is complicated because the light emitting device and the light receiving device must be disposed within a narrow space. It has had another problem that its power consumption increases to operate the light emitting device and the light receiving device.
The present invention has been devised in view of the problems described above and its object is to provide an electronic clock and a pointer position detecting method for detecting the pointer position accurately without adding individual electric device.
SUMMARY OF THE INVENTION
In order to achieve the above-mentioned object, an inventive electronic clock comprises reference signal generating means for generating a reference signal; pulse control means for outputting a plurality of pulse signals whose strength is different based on the reference signal to a motor to drive the motor; a wheel train which is rotated by the motor; indicator means which is rotated by the wheel train; position detecting means for detecting predetermined position of the indicator means; and rotation judging means for outputting a rotation signal or a non-rotation signal by detecting whether or not the motor rotates. It is also provided with high load means for applying high load to the wheel train at constant cycle to rotate the motor only when the high load is applied to the wheel train and a pulse signal of predetermined strength or more is outputted to the motor; the pulse control means outputs a normal driving pulse, outputting a first auxiliary driving pulse whose strength is greater than that of the normal driving pulse when the rotation judging means outputs a non-rotation signal after outputting the normal driving pulse or outputting a second auxiliary driving pulse whose strength is greater than the first auxiliary driving pulse and the predetermined strength when the rotation judging means outputs the non-rotation signal after outputting the first auxiliary driving pulse; and the position detecting means judges that the indicator means is located at the predetermined position when the second auxiliary driving pulse is outputted.
An inventive pointer position detecting method for detecting that indicator means has come to predetermined position, comprises steps of: applying high load to a wheel train for rotating the indicator means at constant cycle so that a motor rotates only when the high load is applied and a pulse signal of predetermined strength or more is outputted to the motor for rotating the wheel train; judging whether or not the motor rotates by outputting a normal driving pulse to the motor; judging whether or not the motor rotates by outputting a first auxiliary driving pulse whose strength is greater than that of the normal driving pulse to the motor when the motor does not rotate by the normal driving pulse; outputting a second auxiliary driving pulse whose strength is greater than the first auxiliary driving pulse and the predetermined strength to the motor when the motor does not rotate by the first auxiliary driving pulse; and judging that the indicator means is located at the predetermined position when the second auxiliary driving pulse is outputted.
Japanese Patent Publication Nos. 63-18148, 63-18149 and 57-18440 have disclosed the technology of detecting that a motor rotates by outputting a relatively weak normal driving pulse to the motor for rotating a wheel train and of always rotating the motor by outputting a relatively strong auxiliary driving pulse when the motor does not rotate by the normal driving pulse. Normally, power consumption of a motor may be reduced by rotating by the normal driving pulse which consumes less power and by using the auxiliary driving pulse whose power consumption is large only when load is applied to the motor by some reason.
Then, the present invention is arranged so that high load is applied to the wheel train when the indicator means comes to predetermined position and the motor rotates only when the high load is applied and a pulse signal of predetermined strength or more is outputted to the motor. While the motor normally rotates by the normal driving pulse or a first auxiliary driving pulse, it does not rotate when high load is applied to the wheel train, so that it is rotated by applying a stronger second auxiliary driving pulse. Accordingly, it becomes possible to detect the predetermined position of the indicator means by the second auxiliary driving pulse because the second auxiliary driving pulse is outputted when the indicator means is located at the predetermined position. Still more, no light receiving device like those in the prior art is required.
For instance, when it is arranged so that high load is applied to the wheel train when the minute hand stands at twelve o'clock, the second auxiliary driving pulse for rotating the motor when the minute hand stand
Adams & Wilks
Roskoski Bernard
Seiko Instruments Inc.
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