EP1443370A1

EP1443370A1 - Radio controllable clock

Info

Publication number: EP1443370A1
Application number: EP03400002A
Authority: EP
Inventors: Ivan W.K. c/o Highway Holdings Ltd. Shum; W.S. c/o Highway Holdings Ltd. Chan
Original assignee: Kienzle Time HK Ltd
Current assignee: Kienzle Time HK Ltd
Priority date: 2003-01-30
Filing date: 2003-01-30
Publication date: 2004-08-04

Abstract

The present invention relates to a radio controllable clock comprising an hour wheel associated to the hour hand of the clock and a minute wheel associated to the minute hand of the clock, the hour wheel being provided with means to interrupt or reflect an intersecting light beam, wherein the minute wheel is coupled to the hour wheel and wherein the hour and the minute wheels are driven by a single stepper motor. The present invention also relates to methods for detecting and adjusting the position of a radio controllable clock.

Description

The present invention relates to a radio controllable clock comprising an hour wheel associated to the hour hand of the clock and a minute wheel associated to the minute hand of the clock, the hour wheel being provided with means to interrupt or reflect an intersecting light beam. The invention also relates to methods for detecting and adjusting the position of a radio controllable clock.
Radio controllable clocks with the above mentioned features are well-known from the state of the art, e.g. from DE 35 13 961 A1. This Patent Application proposes the use of several stepper motors and/or different types of markings on transparent gear wheels and teaches that when coupling more than one hand to a single stepper motor various markings on each gear wheel that intersects with a light beam are necessary to ensure a well-defined detection of the position of the gear wheels. Thus a relative high number of different components is needed which makes the proposed clock and its assemblage expensive.
The object of this invention is to overcome the above mentioned drawbacks and to provide a clock that has a simple design. This object is achieved by coupling the minute wheel to the hour wheel and driving the hour and the minute wheels by a single stepper motor.
By providing a single stepper motor that drives the hour and the minute wheel and by coupling the minute wheel to the hour wheel while providing the hour wheel with means to interrupt or reflect an intersecting light beam, a very simple and inexpensive design is proposed. This design requires a minimum number of components and yet it is still possible to detect and adjust the positions of the hour and the minute hands of this clock.
Since the minute hand and the hour hand have pre-determined positions in relation to each other, there is no need to detect the positions of both hands i.e. their associated wheels for adjusting the time according to a received radio signal. When the light beam is interrupted or reflected by the corresponding means of the hour wheel, the hand associated to the hour wheel is at a particular position, for example at a 6 o'clock position. Then the position of the minute wheel which is coupled to the hour wheel (when directly engaging each other in a 12:1 gear ratio) is known, too. In the case of the example, when the hour hand is at the 6 o'clock position, the minute hand has to be at the 12 o'clock position. This information alone is sufficient to detect the position of both hands of the clock and from there adjust them according to a received radio signal.
The appropriate means to interrupt or reflect the intersecting light beam can be chosen according to the light beam arrangement. For example, if a light transmitting and a light receiving element are arranged on opposite sides of the hour wheel, the hour wheel can be non-transparent and be provided with an aperture. In this case the means to interrupt the light beam is the hour wheel itself and the aperture allows the passage of the light beam when it is in a corresponding position. This means that when the hour wheel is turned, the light beam is blocked until the aperture of the hour wheel is in a position to allow the passage of the light beam. If, for example, the corresponding position of the hour hand is at 6 o'clock, the minute hand has to be at the 12 o'clock position.
Another possibility is to arrange the light transmitting and the light receiving elements of the light beam on the same side with respect to the hour wheel. In this case the whole hour wheel can be provided with a reflecting layer except for an aperture that allows the passage of the light beam. The hour hand position would then be detected, when the light beam is not reflected by the hour wheel. It is also possible to provide a transparent gear wheel that is provided with a reflecting layer in one sector only. The hour hand position would then be detected, when the light beam is reflected by the reflecting sector of the hour wheel.
In a preferred embodiment, the hour wheel is transparent and is provided with a non-transparent zone to block the intersecting light beam. In this case, the light transmitting and the light receiving element of the light beam are arranged on opposite sides of the hour wheel. The non-transparent zone can be integrated into or attached to the hour wheel. It is preferred, that the non-transparent zone covers a sector of the hour wheel, so that the detection of the position in which the light beam is blocked is not dependent on precise alignment of the light beam and the hour wheel with respect to the distance of the center of the wheel in a radial direction.
The described embodiments allow a reliable and precise detection of the position of the hour and the minute hand.
However, there might be a need for a reliable detection of the various hands that is even more precise. Therefore, it is proposed that not only the hour wheel but also the minute wheel is transparent and provided with a non-transparent zone to interrupt the intersecting light beam and that a time measuring unit is provided that can measure the time periods in which the light beam is blocked by either one of the non-transparent zones, while the wheels are driven by the stepper motor, that a memory unit is provided in which reference blocking times can be stored and that a comparator unit is provided which can compare measured blocking times and reference blocking times.
This embodiment allows the detection of the position of a particular wheel when the corresponding non-transparent zone blocks the light beam for a particular time period. This measured blocking time can be compared to a reference blocking time. Since the hour and the minute wheels turn at different speeds, identically sized non-transparent zones will block the intersecting light beam a longer time period for the hour wheel and a shorter time period for the minute wheel. This information can be processed by providing a memory unit to store reference blocking times and a comparator to compare measured blocking times and reference blocking times.
The non-transparent zones provided on the hour and the minute wheel can but do not necessarily have to cover the same angular range. The reference blocking times can be determined by measuring blocking times at a reference speed of the stepper motor. These reference blocking times can then be stored in the memory unit. If the non-transparent zones are identical, the blocking time for the hour wheel will be 12 times greater than the blocking time for the minute wheel. If the non-transparent zones are not identical, the ratio of the blocking times will change accordingly.
When detecting the positions of the hour and the minute wheels, the wheels can be turned at the reference speed of the stepper motor to measure the various blocking times. It is possible to compare the measured and the reference blocking times to find matching values and thereby determine, which non-transparent zone has just blocked the light beam. However, it is also possible, that a delta of time is added to or deducted from each reference blocking time. In this case the measured blocking times and the reference blocking times will deviate from each other. In this case the comparison of the measured and the reference blocking times will lead to the result, that a particular measured blocking times is smaller than both reference times, greater than one of the reference times or greater than both reference times. From this comparison the information, which non-transparent zone has just blocked the light beam, can be derived.
For example, the reference blocking times at a reference speed of the stepper motor are 720 ms for the hour wheel and 60 ms for the minute wheel. A delta of 2 ms adds up to 722 ms for the hour wheel and 62 ms for the minute wheel. When the positions of the hour and the minute wheels are to be detected, the wheels are turned at the reference speed of the stepper motor until one of the non-transparent zones blocks the intersecting light beam. For example, a blocking time period of 60.5 ms is measured. This value is compared to 62 ms and to 722 ms and therefore smaller than both of these values. This means that the measured blocking time of 60.5 ms corresponds to the non-transparent zone of the minute wheel and therefore to a particular position of the minute hand associated to the minute wheel. If the blocking time that is measured next is 60.3 ms this value still corresponds to the minute wheel, which non-transparent zone has once again passed the light beam. (The chosen values of 60.5 and 60.3 ms show by way of example, that even if not precisely turning the wheels at the exact reference speed of the stepper motor, the position of the wheels can still be detected reliably.)
Still referring to the above mentioned example, a measuring time of 719.7 ms is measured and compared to 62 and 722 ms, respectively. The value of 719.7 ms is smaller than one of the reference values only. Therefore, the hour wheel must just have blocked the light beam.
It is also possible to provide a single reference value, for example 390 ms as a value between 60 ms and 720 ms. A measured blocking time will either be greater or smaller than this single reference value. A greater blocking time will refer to the blocking of the light beam by the non-transparent zone of the hour wheel and a shorter blocking time will refer to the blocking of the light beam by the non-transparent zone of the minute wheel.
In still another embodiment it is possible to provide reference blocking times by turning the wheels at a fixed speed of the stepper motor, storing the blocking time first measured as a reference blocking time in the memory unit and compare the blocking time measured next with the reference blocking time in the memory unit, that is the previously measured blocking time. If the just measured blocking time and the previously measured blocking time are exactly the same or deviate from each other by a small tolerance only, the same non-transparent zone has passed the light beam twice. Since the minute wheel turns faster than the hour wheel, this non-transparent zone will belong to the minute wheel. As soon as a comparison of a blocking time just measured with the blocking time previously measured (reference blocking time), shows a great deviation, this means that the non-transparent zone of the hour wheel has just passed the light beam.
In another embodiment, a transparent second wheel associated to the second hand of the clock is provided, the second wheel having a non-transparent zone to interrupt the intersecting light beam and being coupled to the minute wheel or the hour wheel, all wheels being driven by a single stepper motor.
The above mentioned principles in detecting the positions of the various hands all apply accordingly. This means, that for example three reference blocking times can be stored in the memory unit, that a delta of time can be added to or deducted from these reference blocking times and that the comparisons of measured and reference blocking times will show, which of the non-transparent zones has just blocked the light beam. By way of example, the three reference blocking times could be 720 ms for the hour wheel, 60 ms for the minute wheel and 1 ms for the second wheel. There could also be two reference blocking times provided only, that are preferably in between (not necessarily exactly in between) two proximate time periods to be measured, for example 390 ms and 30 ms for blocking times expected to be around 720, 60 and 1 ms for the non-transparent zones of the hour, minute and second wheel, respectively.
It is preferred, that the stepper motor is controlled by a micro-controlling unit so that the stepper motor can be controlled at repeatable precise speeds. This micro-controlling unit can also be used to integrate the time measuring unit, the memory unit and/or the comparator.
The invention also relates to a method for adjusting the position of a radio controllable clock comprising an hour wheel associated to the hour hand of the clock, a minute wheel associated to the minute hand of the clock and coupled to the hour wheel, the hour and the minute wheel being driven by a single stepper motor, the hour wheel being provided with means to interrupt or reflect an intersecting light beam, wherein the wheels are moved until the hour wheel blocks or reflects the intersecting light beam, and wherein the wheels are moved from the position in which the hour wheel blocks or reflects the intersecting light beam into a predetermined position or a position according to a received radio signal.
This method allows to adjust the position of the hour and the minute hand with few and simple steps. Basically the wheels are turned until the predominant state of the light beam changes. Upon this change, which indicates the position of the non-transparent zone of the hour wheel being at the position of the intersecting light beam, the hour and the minute wheels can be driven by the single stepper motor into a predetermined position (e.g. 12 o'clock for both hands) or a predetermined position according to a received radio signal.
It is of course possible to drive the hour and the minute wheels into a predetermined position and from there into a position according to a received radio signal. For example, if the light beam is at the 6 o'clock position of the clock and the light beam is blocked by the non-transparent zone of the hour wheel, the minute wheel can be turned 6 times 60 steps so that the hour and the minute hand are at the 12 o'clock position and from there the hour and the minute hand can be adjusted according to a received radio signal. If the received radio signal is 02:15h , the minute wheel will be turned 135 steps (2 times 60 steps plus 15 steps). Of course, alternatively it would have been possible to turn the minute wheel directly 395 steps after detection of the hour wheel being at the 6 o'clock position to move the hour and the minute hand into the 02:15h position.
A second wheel associated to the second hand of the clock can also be provided and be coupled to the minute wheel or the hour wheel, all wheels being driven by a single stepper motor for this method for adjusting the position of a radio controllable clock.
The invention also relates to a method for detecting the position of a radio controllable clock, the clock comprising an hour wheel associated to the hour hand of the clock, a minute wheel associated to the minute hand of the clock and coupled to the hour wheel, the hour and the minute wheel being driven by a single stepper motor, the hour and the minute wheels being transparent and provided with non-transparent zones to block the intersecting light beam, a time measuring unit, a memory unit and a comparator, wherein the wheels are moved until the intersecting light beam is blocked by one of the non-transparent zones, the time period in which the light beam is blocked by one of the non-transparent zones is measured, wherein the measured blocking time is compared to reference blocking times stored in a memory, and wherein the mentioned steps are carried out until the measured blocking time corresponds to the hour wheel.
This method allows to detect the position of the clock by detecting the position of the hour wheel only. However, the position of the minute wheel is known, too, if the non-transparent zone of the minute wheel has blocked the light beam at least once. It might be, that (by chance) the first time that the light beam is blocked, it is blocked by the non-transparent zone of the hour wheel. In this case it is possible to move the wheels until the intersecting light beam is blocked one more time by the minute wheel.
According to a method for adjusting the position of a radio controllable clock the wheels can be moved from the position in which the hour or minute wheel blocks the intersecting light beam into a predetermined position or a position according to a received radio signal or into a predetermined position and from there into a position according to a received radio signal.
Finally the invention relates to a method for detecting the position of a radio controllable clock, the clock comprising an hour wheel associated to the hour hand of the clock, a minute wheel associated to the minute hand of the clock and a second wheel associated to the second hand of the clock, all wheels being coupled to each other and being driven by a single stepper motor, all wheels being transparent and provided with non-transparent zones to block an intersecting light beam, a time measuring unit, a memory unit and a comparator, wherein the wheels are moved until the intersecting light beam is blocked by one of the non-transparent zones, the time period in which the light beam is blocked by one of the non-transparent zones is measured, wherein the measured blocking time is compared to reference blocking times stored in a memory, and wherein the mentioned steps are carried out until the measured blocking time corresponds to the hour wheel.
This method allows to detect the position of the clock by detecting the position of the hour wheel only. However, the position of the minute wheel and the second wheel are known, too, if each of the non-transparent zones of the minute and of the second wheel have blocked the light beam at least once. It might be, that (by chance) the first time that the light beam is blocked, it is blocked by the non-transparent zone of the hour wheel. In this case it is possible to move the wheels until the intersecting light beam is blocked one more time by the minute wheel and/or until the intersecting light beam is blocked one more time by the second wheel.
According to a method for adjusting the position of a radio controllable clock the wheels can be moved from the position in which the hour, minute or second wheel blocks the intersecting light beam into a predetermined position or a position according to a received radio signal or into a predetermined position and from there into a position according to a received radio signal.

Claims

Radio controllable clock comprising an hour wheel associated to the hour hand of the clock and a minute wheel associated to the minute hand of the clock, the hour wheel being provided with means to interrupt or reflect an intersecting light beam, characterized in that the minute wheel is coupled to the hour wheel and that the hour and the minute wheels are driven by a single stepper motor.
Radio controllable clock according to claim 1, characterized in that the hour wheel is transparent and provided with a non-transparent zone to block the intersecting light beam.
Radio controllable clock according to claim 2, characterized in that the minute wheel is transparent and provided with a non-transparent zone to interrupt the intersecting light beam and that a time measuring unit is provided that can measure the time periods in which the light beam is blocked by either one of the non-transparent zones, while the wheels are driven by the stepper motor, that a memory unit is provided in which reference blocking times can be stored and that a comparator unit is provided which can compare measured blocking times and reference blocking times.
Radio controllable clock according to claim 3, characterized in that the reference blocking times are determined by measuring blocking times at a reference speed of the stepper motor.
Radio controllable clock according to one of the claims 3 or 4, characterized in that a delta of time is added to or deducted from each reference blocking time.
Radio controllable clock according to one of the claims 3 to 5, characterized in that a transparent second wheel associated to the second hand of the clock is provided, the second wheel having a non-transparent zone to interrupt the intersecting light beam and being coupled to the minute wheel or the hour wheel, all wheels being driven by a single stepper motor.
Radio controllable clock according to any of the preceding claims, characterized in that the stepper motor is controlled by a micro-controlling unit.
Method for adjusting the position of a radio controllable clock comprising an hour wheel associated to the hour hand of the clock, a minute wheel associated to the minute hand of the clock and coupled to the hour wheel, the hour and the minute wheel being driven by a single stepper motor, the hour wheel being provided with means to interrupt or reflect an intersecting light beam, characterized in the steps of

moving the wheels until the hour wheel blocks or reflects the intersecting light beam, and

moving the wheels from the position in which the hour wheel blocks or reflects the intersecting light beam into a predetermined position or a position according to a received radio signal.
Method according to claim 8, characterized in that a second wheel associated to the second hand of the clock is provided and coupled to the minute wheel or the hour wheel, all wheels being driven by a single stepper motor.
Method according to claim 8 or 9, characterized in that the wheels are moved from the position in which the hour wheel blocks or reflects the intersecting light beam into a predetermined position and from there into a position according to a received radio signal.
Method for detecting the position of a radio controllable clock according to any of the claims 3 to 7, characterized in that the measured blocking times are compared to the reference blocking times.
Method for adjusting the position of a radio controllable clock according to any of the claims 3 to 7, characterized in that the measured blocking times are compared to the reference blocking times to detect the positions of the hands and that upon detection of these positions the clock is set according to a received radio time signal.
Method for detecting the position of a radio controllable clock, the clock comprising an hour wheel associated to the hour hand of the clock, a minute wheel associated to the minute hand of the clock and coupled to the hour wheel, the hour and the minute wheel being driven by a single stepper motor, the hour and the minute wheels being transparent and provided with non-transparent zones to block the intersecting light beam, a time measuring unit, a memory unit and a comparator, characterized in the steps of

moving the wheels until the intersecting light beam is blocked by one of the non-transparent zones,

measuring the time period in which the light beam is blocked by one of the non-transparent zones,

comparing the measured blocking time to reference blocking times stored in a memory, and

carrying out the above mentioned steps until the measured blocking time corresponds to the hour wheel.
Method according to claim 13, characterized in the step of moving the wheels until the intersecting light beam is blocked one more time by the minute wheel.
Method for adjusting the position of a radio controllable clock according to the method for detecting the position of a radio controllable clock according to claim 13 or 14, characterized in the step of moving the wheels from the position in which the hour or minute wheel blocks the intersecting light beam into a predetermined position or a position according to a received radio signal.
Method according to any of the claims 13 to 15, characterized in that the wheels are moved from the position in which the hour or minute wheel blocks the intersecting light beam to a reference position and from there into a position according to a received radio signal.
Method for detecting the position of a radio controllable clock, the clock comprising an hour wheel associated to the hour hand of the clock, a minute wheel associated to the minute hand of the clock and a second wheel associated to the second hand of the clock, all wheels being coupled to each other and being driven by a single stepper motor, all wheels being transparent and provided with non-transparent zones to block an intersecting light beam, a time measuring unit, a memory unit and a comparator, characterized in the steps of

moving the wheels until the intersecting light beam is blocked by one of the non-transparent zones,

measuring the time period in which the light beam is blocked by one of the non-transparent zones,

comparing the measured blocking time to reference blocking times stored in a memory,

carrying out the above mentioned steps until the measured blocking time corresponds to the hour wheel.
Method according to claim 17, characterized in the step of moving the wheels until the intersecting light beam is blocked one more time by the minute wheel.
Method according to claim 17 or 18, characterized in the step of moving the wheels until the intersecting light beam is blocked one more time by the second wheel.
Method for adjusting the position of a radio controllable clock according to the method for detecting the position of a radio controllable clock according to one of the claims 17 to 19, characterized in the step of moving the wheels from the position in which the hour, the minute or the second wheel blocks the intersecting light beam into a predetermined position or a position according to a received radio signal.
Method according to any of the claims 17 to 20, characterized in that the wheels are moved from the position in which the hour, the minute or the second wheel blocks the intersecting light beam to a reference position and from there into a position according to a received radio signal.