U.S. patent number 3,889,460 [Application Number 05/371,084] was granted by the patent office on 1975-06-17 for method and apparatus for correcting time in an electronic wristwatch.
This patent grant is currently assigned to Kabushiki Kaisha Suwa Seikosha. Invention is credited to Okito Naito, Hideaki Yasukawa.
United States Patent |
3,889,460 |
Yasukawa , et al. |
June 17, 1975 |
Method and apparatus for correcting time in an electronic
wristwatch
Abstract
An electronic timepiece having a pulse generator producing a
high frequency time standard signal, a divider circuit formed from
a plurality of series-connected divider stages for producing low
frequency timing signals in response to said time standard signal
and a device for displaying time in response to said timing
signals, is provided with a correction circuit disposed in said
divider circuit. The correction circuit enables the use of a new
method and apparatus for providing a correction signal to the
divider stages counting seconds to reset the divider stages to zero
seconds during use of the watch, to thereby correct the accuracy of
the second display.
Inventors: |
Yasukawa; Hideaki (Suwa,
JA), Naito; Okito (Suwa, JA) |
Assignee: |
Kabushiki Kaisha Suwa Seikosha
(Tokyo, JA)
|
Family
ID: |
13161345 |
Appl.
No.: |
05/371,084 |
Filed: |
June 18, 1973 |
Foreign Application Priority Data
|
|
|
|
|
Jun 19, 1972 [JA] |
|
|
47-61101 |
|
Current U.S.
Class: |
368/217; 368/185;
368/223; 968/915 |
Current CPC
Class: |
G04G
5/041 (20130101) |
Current International
Class: |
G04G
5/00 (20060101); G04G 5/04 (20060101); G04c
003/00 (); G04b 019/38 (); G04b 027/00 () |
Field of
Search: |
;58/23,5R,85.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Jackmon; Edith Simmons
Attorney, Agent or Firm: Blum Moscovitz Friedman &
Kaplan
Claims
What is claimed is:
1. An electronic timepiece comprising oscillator means for
producing a high frequency time standard signal, divider means for
producing low frequency timing signals from said high frequency
time standard signals including a plurality of series-connected
divider stages, certain of said divider stages corresponding to
seconds display, means for the digital display of time in response
to said timing signals, said digital display means displaying at
least seconds and minutes, said seconds divider stages providing a
substantially square-wave output signal having a period of 1 minute
to the next divider stage, and correction means for applying a
reset signal to said certain divider stages which correspond to the
incorrect time displayed, said correction means being adapted to
set the second digital display to zero without affecting the minute
digital display when said reset signal is applied to said certain
dividers during the first half cycle of said output signal when the
seconds digital display means is 30 or less and to set the second
digital display to zero and increase the minute digital display by
one when said reset signal is applied to said certain dividers
during the second half cycle of said output signal when said
seconds digital display read more than 30.
2. An electronic timepiece as claimed in claim 1, wherein said
certain divider stages are a 1/6 divider stage corresponding to a
1-second display and 1/3 and 1/2 divider stages corresponding to a
10-second display.
3. An electronic timepiece as claimed in claim 2, wherein said
correction means includes a wave shaping means for supplying said
reset signal to said certain divider stages in the form of a
pulse.
4. An electronic timepiece as claimed in claim 3, wherein said
correction means includes a manually operated switch means coupled
to said wave shaping means, for selectively causing the application
of said pulse reset signal to said certain divider stages.
5. An electronic timepiece as claimed in claim 4, wherein a second
manually operated switch means is coupled to said next divider
stage to effect correction of the minutes display.
6. A method for correcting errors of minus 30 seconds or less in an
electronic timepiece having oscillator means for producing a high
frequency time standard signal, divider means for producing low
frequency timing signals from said high frequency time standard
signal including a plurality of series-connected divider stages,
certain of said divider stages producing a square wave timing
signal to the next divider stage and means for the digital display
of time including at least a seconds and a minutes display in
response to said timing signals, the method comprising the steps
of, at the nearest correct minute indication, in response to the
second half cycle of the square wave timing signal resetting the
divider stages producing the timing signals associated with the
digital display of seconds to zero and increasing the count of the
next divider stages producing timing signals associated with the
digital display of minutes by one.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to electronic timepieces
incorporating digital displays, and in particular, to a method and
apparatus for correcting the time displayed by electronic
timepieces such as wristwatches. Electronic timepieces such as
wristwatches have become known for their high accuracy and it is
very common for such wristwatches to sustain an accuracy rate
within plus and minus 30 seconds per month. Such accuracy rates
will cause watches which include the display of seconds, a feature
incorporated into very accurate timepieces, to display the wrong
time. Normal time setting, such as during insertion of a new
battery, in the timepiece, is generally limited to setting the hour
and minute. Heretofore, the method of seconds correction during
normal use entailed the holding of the second hand in a waiting
position until the correct time was reached and then releasing the
hand. Such a method required operating a switch two times and
considerable waiting which renders such method less than completely
satisfactory. Moreover, because wristwatches are limited in the
space provided for electronic circuitry, correction circuitry which
has been heretofore suggested, has not provided the accuracy and
the minimal space displacement which is necessary in such watches.
Accordingly, it is desirable to produce a small sized digital
electronic timepiece, particularly a wristwatch which can be
corrected by a simple method and apparatus which includes the
addition of a correction signal to the counting circuit of the
watch.
SUMMARY OF THE INVENTION
Generally speaking, in accordance with the invention, an electronic
timepiece is provided including pulse generator means for
generating a high frequency time standard signal, divider means
formed from a plurality of series-connected divider stages for
producing low frequency timing signals in response to said high
frequency time standard signal and representative of present time,
and digital display means for the digital display of time in
response to said timing signals. A correction circuit is coupled to
certain of said divider stages to apply a reset signal thereto.
A method for correcting the seconds display during normal use of
the timepiece is provided when the seconds display is incorrect
within a time period of plus and minus 30 seconds. Upon observing
that the actual time is exactly at a minute indication, an operator
provides a correction signal to certain of the divider stages which
correspond to the display of seconds, the correction signal
effecting the reset of such certain divider stages to zero seconds
and the restarting thereof. Where the time displayed is slow by 1
to 30 seconds, application of the correction signal further effects
an advancement of the minute display.
Accordingly, it is an object of this invention to provide a
small-sized electronic timepiece provided with a digital display
and having an improved correction circuit.
Still another object of this invention is to provide an improved
small-sized electronic timepiece provided with an improved
correction circuit and method for utilizing the same.
Still another object of the invention is to provide an improved
method for correcting small-sized electronic timepieces.
The invention accordingly comprises several steps and the relation
of one or more of such steps with respect to each of the others,
and the apparatus embodying features of the construction,
combination of elements and arrangements of parts which are adapted
to effect such steps, all as exemplified in the following detailed
disclosure, and the scope of the invention will be indicated in the
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the invention, reference is had to
the following description taken in connection with the accompanying
drawings, in which:
FIG. 1 is a perspective view of an electronic wristwatch
constructed in accordance with the preferred embodiment of the
instant invention;
FIG. 2 is a block diagram of the circuitry of the electronic
wristwatch illustrated in FIG. 1;
FIG. 3 is a perspective view of the digital display of the
electronic timepiece of FIG. 1 illustrating a first mode of
correction;
FIG. 4 is a perspective view of the digital display of the
electronic timepiece of FIG. 1 illustrating a second mode of
correction;
FIG. 5 is a circuit diagram including the correction circuit of the
electronic timepiece of FIG. 1; and
FIG. 6 is a wave diagram corresponding to the circuit of FIG.
5.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, an electronic timepiece is illustrated therein
and includes a digital display 5, for displaying the present time
in terms of minutes, hours and seconds. The front of the watch
further includes time setting switches 6 and 7 which enable setting
and correction of the hours and the minutes digits respectively of
display 5. Switch 8 is a time correcting switch used in the method
and apparatus of the instant invention.
Referring now to FIGS. 2 and 5, the circuitry of the electronic
timepiece of FIG. 1 is illustrated, including a pulse generator 1,
which may take the form of a quartz crystal oscillator or the like.
A high frequency time standard signal output of pulse generator 1
is applied to divider and distributor circuit 2 which includes a
divider chain which divides the time standard signal into time
keeping signals such as hours, minute, and second signals. The
dividers of the divider chain producing the time keeping signals
may be selectively corrected by means of correction circuit 4
including switches 6, 7 and 8. The instantaneous time-keeping
signals are applied to distributor circuits which place them in a
form for driving the respective digits of digital display 3.
As shown in FIG. 5, the divider chain of divider and distributor
circuit 2 includes divider circuits 9 through 15 each of which
produces instantaneous timing signals counted therein for
application to distributor circuits 16, 17 and 18 as will
hereinafter be discussed. In the divider circuit depicted in FIG.
5, divider circuit 9 receives a high frequency signal such as would
be supplied by the crystal oscillator and produces a 1-second
signal having a period of 1 second. The 1-second signal from
divider circuit 9 is then applied to a series chain of divider
circuits 10 through 15 which produce timing signals for display.
Thus, divider circuit 10 is a 1/10 divider circuit for producing a
10-second signal; divider circuit 11 is a 1/3 divider for producing
a 1/2 minute signal; divider circuit 12 is a 1/2 divider for
producing a 1-minute signal; divider circuit 13 is a 1/10 divider
for producing a 10-minute signal; divider circuit 14 is a 1/6
divider circuit for producing a 1-hour signal; and divider circuit
15 is a 1/12 divider circuit for producing a 12 hour signal.
Divider circuits 10 through 15 supply instantaneous timing signals
counted therein to distributors 16, 17 and 18 which correspond
respectively to the second, minute and hour digits of the digital
display, divider circuits 10, 11 and 12 being connected to
distributor 16, divider circuits 13 and 14 being connected to
distributor 17 and divider circuit 15 being connected to
distributor 18.
The time correcting circuit 4 includes conventional time setting
switches 23 and 24 which correspond to time setting switches 6 and
7 respectively of FIG. 1, and time correcting switch 22 which
corresponds to switch 8 of FIG. 1. The time correcting switch 22 is
coupled to a waveform shaping circuit 19 which in turn is coupled
to divider stages 9 through 12. By application of a correction
signal to divider circuit stages 9 through 12 by actuation of
switch 22, a reset signal is supplied by the wave shaping circuit
19 to the divider stages to thereby reset the divider stages. Time
setting switches 23 and 24 are coupled to control circuits 20 and
21 which control circuits shape the waveform of the time setting
signal from switches 23 and 24 and the output or carry signal from
the next previous divider stage and supply corrected carry signal
to the next subsequent divider stage in response to the respective
signals supplied thereto. Thus, control circuit 20 receives the
carry signal from divider 12 and the correction signal from switch
23 and insures that the count of the signal applied to divider 13
is increased by one for each operation of switch 23 to effect
correction of the minutes digits of the digital display. Correction
of the hours digits is effected in a like manner by switch 24 and
control circuit 21. Control circuits 20 and 21 are each adapted to
produce a positive pulse of short duration for each positive
excursion of the signals applied thereto.
Reference is now made to FIG. 6 in which waveform 25 corresponds to
the correction signal supplied from wave shaping circuit 19 to the
divider stages 9 through 12; waveform 26 corresponds to the
1-minute signal supplied from divider circuit 12 to control circuit
20; and, waveform 27 corresponds to the output of control circuit
20 in the absence of any signals supplied from time setting switch
23.
Where the error is plus or minus 30 seconds or less, there are two
possible modes of correction using time correction switch 22,
depending on whether the watch is running fast or slow. The first
mode where the watch is fast is illustrated in FIG. 3, where the
time before correction is 10 hours, 59 minutes and 25 seconds. An
operator will use a standard reference source for telling time such
as a radio, T.V. or telephone operator to aid in correcting the
time. When the standard reference time is 10 hours, 59 minutes and
0 second, switch 22 is closed and a reset pulse is generated in
wave shaping circuit 19 which is then supplied to divider stages 9
through 12, thus resetting each of said divider stages to zero. In
this case, the reset signal 25 depicted in FIG. 6, is applied to
divider stage 12 during a period (0-30 seconds) that the output is
already positive so that resetting has no immediate effect on the
output signal 26 of divider circuit 12. The width of the positive
pulse of output signal 26 during which switch 22 is operated is
increased since the count of seconds starts again from zero
seconds. Thereafter, signal 26 resumes its normal 1-minute period.
The next pulse of signal 27 from central circuit 20 is thus
retarded by an amount sufficient to permit correction. The
application of the reset signal at the proper time thus corrects
the time from 10 hours 59 minutes and 25 seconds to 10 hours and 59
minutes and 0 seconds, and immediately restarts the timing signals
so as to then provide normal use of the wristwatch.
The second mode of operation for use when the watch is running slow
by 30 seconds or less is illustrated with reference to FIG. 4. In
this mode correction is effected when the seconds display reads
above 30 seconds, at which time output signal 26 from divider stage
12 is negative. If a correction pulse 25 from wave-form shaping
circuit 19 is applied to divider stages 9 through 12 to reset the
divider stages during this period, the resetting stage 12 to zero
makes the output signal 26 positive. The earlier than normal
positive excursion of signal 26 produces a pulse out of control
circuit 20 (in signal 27) to advance the minute display by one.
Thus, the watch display as depicted in FIG. 4 shows a time of 10
hours 59 minutes and 37 seconds, and upon application of a
correction signal by an operator corresponding to an 11 o'clock
standards reference time, the time on the watch will be corrected
to 11 o'clock and the watch will continue to operate in a normal
mode.
It is understood that time correction of a wristwatch in normal use
is performed, and that electronic circuits can be easily produced
which will consume a minimum of power, yet be miniature enought to
be used in the small space displacement required in an electronic
wristwatch. The use of C-MOS integrated circuitry will provide low
power consumption and the requisite small size to such wristwatch
components.
It will thus be seen that the objects set forth above, among those
made apparent from the preceeding description, are efficiently
attained and, since certain changes may be made in carrying out the
above method, and in the construction set forth without departing
from the spirit and scope of the invention, it is intended that all
matter contained in the above description and shown in the
accompanying drawings shall be interpreted as illustrative and not
in a limiting sense.
It is also to be understood that the following claims are intended
to cover all of the generic and specific features of the invention
herein described, and all statements of the scope of the invention
which, as a matter of language, might be said to fall
therebetween.
* * * * *