DE69409612T2 - Electronic analog chronograph with single-hand - Google Patents

Description

The present invention relates to an electronic analog chronograph comprising at least a first hand which makes one revolution per minute and indicates the seconds or fractions of a second and is controlled by a first control circuit, and a second hand which indicates and accumulates minutes and is controlled by a second control circuit, which second hand moves one minute when the first has passed sixty seconds, and pushers which can be operated by the user, by means of which the chronograph can be started, stopped, stopped and reset to zero.

The electronic analogue chronographs available on the market correspond to the definition above. Generally speaking, they have a first hand or central second hand that makes one revolution every minute and indicates the seconds or fractions of a second. A second hand, rotating on a smaller dial, advances by one step, namely one minute, when the first hand has made one revolution. This is the minute counter or totaliser, whose hand makes one revolution every thirty minutes, and this is the case in the most common models. Certain chronographs also have a third hand that makes one revolution every twelve hours. This is an hour counter or totaliser.

To start the chronograph, press a first button, generally located at two o'clock. To stop it, press the same button again, which allows you to read the stopped time. To reset the chronograph, press a second button, generally located at four o'clock. The hands then position themselves at twelve o'clock.

If the chronograph has a stopping or retrieving function - and this is the case for the chronograph which is the subject of the present invention - pressing the second pusher when the chronograph is in operation causes the hands to stop or retract at the position where they were when the second pusher was pressed.

In the stop function, the counters continue to increment so that when the chronograph is restarted by pressing the second pusher again, the hands then advance rapidly until they show the measured time they would have shown if the stop function had not been activated. This is the well-known catch-up function of mechanical chronographs.

The mode of operation of a state-of-the-art electronic analog chronograph with a single hand can be explained by means of the partial electrical diagram of Figure 3, where only the circuits used for this function are shown.

The system includes a fifth-of-a-second counter 1, which is incremented by a 5 Hz signal. Note that this could be a second counter with a 1 Hz supply. Counter 1 increments another minute totalizer counter 2 every minute.

One could stop here if it were a numerical chronograph with an LCD display. In fact, impulses are sent to the input of the fifth-of-a-second counter when the chronograph is started and are cancelled when it stops, with a reset being carried out during the zeroing process. During the shutdown process, the output of the counter to the decoder is blocked and then released during the retrieval process which immediately follows.

Returning to the analogue chronograph in question, it can be observed that counters 1 and 2 act as memories which are continuously incremented, the first by a 5 Hz time base signal, the second by a one-minute signal. The system also comprises two blocks 3 and 4, called the second hand control and the totalizer control respectively. Each of these blocks actually contains a control circuit which acts on the second hand 10 and the minute hand 20 respectively, and a counter which is only incremented when the rotors driving the second hand 10 and the hand 20 respectively are acted upon by an impulse to the coil or coils of the stepper motor or motors. The count of counter 1 and that of counter 3 are constantly checked by a comparator 5, the output of which takes the value 1 if these counts are identical, or the value 0 if not. The count of counter 2 and that of counter 4 are checked in the same way by a comparator 6. The output of comparator 5 controls a switch 7 which sends to the input of the second hand control 3 either the signal of 5 Hz if the output of comparator 5 is in the state 1, or a high frequency signal, 32 or 50 Hz, if this output is in the state 0. Likewise, the output of the comparator 6 controls a switch 8 which sends to the input of the totalizer control 4 either the output at one minute of the second hand control if the output of the comparator 6 is in the state 1, or a high frequency signal, 16 or 25 Hz, if this output is in the state 0.

The control circuits 3 and 4 can be blocked by a split or stop signal. When the stop function is set, the split signal is in the 0 state and the circuits 3 and 4 are blocked and remain so until this signal changes to 1 on command. At this moment, the control circuits 3 and 4 receive their fast signals through the switch 7, since the count of counter 1 is different from that of counter 3. It is then the catch-up function that operates until the comparators 5 and 6 themselves change to the 1 state, which occurs when the counts of counters 1 and 3, or 2 and 4, are equal. The pointers 10 and 20 then resume their normal operation.

In the electronic analog chronograph just described, the second and minute hands are therefore stopped, whether the chronograph is in the stop function or in the standstill function. It is therefore not possible for the user to know what state his instrument is in and to distinguish between the stop state, in which the internal counters continue to increment, and the standstill state, in which these counters are stopped. This can lead to incorrect operations being carried out.

Document GB-A-2 005 875 describes a chronograph equipped with a first second hand which advances in steps of one second and makes one revolution in one minute, and with a second minute hand which makes one revolution in thirty minutes and advances in steps of one minute. These two hands are driven by a single motor. The chronograph further comprises a third hundredth of a second hand which advances in steps of one hundredth and makes one revolution in one second. This third hand is driven by a second motor independent of the first. In this document indicated that the second hand (and consequently the minute hand) and the hundredths of a second hand are stopped when the chronograph is stopped. There is therefore nothing to suggest that when the chronograph is stopped only the hundredths hand continues to move while the other two hands are stopped. Even if this were the case, how would one have time to read an intermediate time when the hundredths hand continues to move?

To avoid these disadvantages, the electronic analog chronograph of the invention is characterized in that means are provided so that when the chronograph is stopped, at least the second minute-accumulating hand continues to indicate and accumulate the minutes in order to indicate to the user that the chronograph is in operation and is not stopped.

The invention will now be understood from the following description and by means of the drawing, which shows two embodiments by way of example, in which drawing:

- Figure 1 is a front view of the chronograph according to an embodiment of the invention,

- Figure 2 is an enlargement of Zone II of Figure 1 ,

- Figure 3 is a partial electrical diagram showing the structure of an electronic analogue chronograph of the state of the art, which diagram has been discussed in the preamble of this document,

- Figure 4 is a partial electrical diagram of a first embodiment of the invention, and

- Figure 5 is a partial electrical diagram of a second embodiment of the invention, which is also illustrated in Figure 1.

Figure 1 shows a front view of the dial and controls of the chronograph according to an embodiment of the invention. It essentially comprises a central second hand 10 rotating on a dial 53 with second divisions 31 and fractional second divisions 30, a minute totalizer consisting of a hand 20 rotating on a dial 55 with minute divisions 33, and first and second pushers 51 and 52. Of course, the chronograph could also comprise an hour totalizer, which has not been shown here.

The chronograph of Figure 1 is completed by a timepiece which has an hour hand 11, a minute hand 12, a small second hand 13 rotating on the dial 54 with the divisions 34 and a hand setting crown 50. This timepiece is driven by a conventional stepping motor and is not part of the subject of the present invention.

The central seconds hand or first hand 10 makes one revolution in one minute, while the minute totaliser or second hand 20 moves one minute when the first hand has completed sixty seconds. The first and second hands are driven independently, either by a stepping motor each or by a motor with a single stator but having two rotors which can be driven separately according to the pulse shapes supplied by the coil, as described in document CH-B-675 940.

The chronograph is started by pressing the button 51 for the first time. The first hand 10 advances by one hundredth of a second and the second hand 20 advances by one minute each time the first hand completes one revolution. The chronograph is stopped by pressing the button 51 again. The time stopped can then be read. The stop function also stops the incrementation of the internal counters. Pressing pusher 51 again restarts the time measurement from the time displayed when the stop was made. The chronograph is reset by pressing the second pusher 52 when the chronograph is stopped. Hands 10 and 20 return to twelve o'clock at an accelerated speed.

If, after having started the chronograph by pressing the first push-button 51, the second push-button 52 is pressed, the chronograph is stopped. The chronograph of the present invention uses means which will appear later in this description so that when the chronograph is stopped, at least the second hand 20 continues to indicate and add up the minutes, the first hand 10 either being stopped or indicating a unit other than the fifth of a second, according to the embodiment used and discussed below. It is therefore understandable that the fact that the second hand 20 continues to indicate and add up the minutes draws the user's attention to the fact that the chronograph is always in operation and not stopped.

After stopping the chronograph, the retrieval function is finally activated by pressing the second pusher 51 again. At this moment, the first hand 10 is driven at an accelerated speed to then indicate the time it would have indicated if the stop function had not been activated, immediately resuming normal operation.

A first embodiment of the invention provides that in the stop function the first hand or central second hand 10 is stopped and the second hand 20 continues to display and accumulate the minutes. In this embodiment, the first and second hands are each driven by a motor with a rotor, a stator and a coil. The two motors are therefore completely independent of each other and their rotor advances when the corresponding coil is acted upon by a pulse. This embodiment will now be explained with the aid of the electrical sub-diagram in Figure 4.

In this first embodiment, the chronograph comprises a first seconds counter 1 which is incremented by a time base signal of 5 Hz. In this case, the hand advances by steps of one fifth of a second. It will be noted that this signal could be a signal of 1 Hz, in which case the hand would advance by steps of 1 second. The chronograph also comprises a second counter 3 which is incremented at each step of the first hand 10, that is to say which is only incremented when the rotor feeding the hand is acted upon by a pulse. The hand 10 is driven by a first control circuit 3 belonging to the same block as that containing the second counter. The control circuit 3 is driven by the time base signal of 5 Hz or by a high frequency signal of, for example, 32 Hz, depending on whether a switch 7 is in a first position 60 for normal operation of the chronograph or in a second position 61. The diagram of Figure 4 also shows that the chronograph comprises a comparator 5 whose task is to compare the count of the first and second counters 1 and 3, in particular when the chronograph is in the stop function. The output signal of the comparator is equal to 1 when these counts are identical and equal to 0 in the opposite case. In the stop function, the control 3 of the hand 10 is blocked by a split signal which is in the 0 state. The hand 10 stops. When the When the stop function is cancelled, the split signal goes to state 1 and the control 3 receives a signal of 32 Hz because the comparator 5 has brought the switch 7 to the second position 61, the counts of the first and second counters being different and the output signal of the comparator 5 being in state 0. The first pointer is thus driven at an accelerated speed until the counts of the first and second counters 1 and 3 are equal, in which case the comparator 5 goes to state 1 and the switch 7 to position 60. The pointer 10 then indicates the time it would have indicated if the stop function had not been activated and then immediately resumes its normal operation at 5 Hz.

What has been said in the previous paragraph is in all respects similar to the chronograph of the prior art described in the preamble to the present invention. Since the invention consists in drawing the user's attention to the fact that his chronograph is stopped and not stopped by leaving the minute totalizer running, the diagram of Figure 4 shows that the minute counter 2, the comparator 6 and the switch 8 present in Figure 3 have been omitted, the block 4 only containing a second circuit 4 without a second counter 2, which is directly controlled by the first counter 1 each time the latter has counted sixty seconds. Thus, during the stop function, the control of the first hand or second hand 10 is blocked, while the totalizer control circuit 4 is incremented every minute by the fifth-of-a-second counter 1, the latter always being incremented by the 5 Hz signal.

A second embodiment of the invention provides that the first hand or central second hand 10 advances by steps of one fifth of a second when the chronograph is in normal operation and by steps of one minute when stopped to form an hour totalizer, the angular step of the first hand being the same for both functions and the second hand continuing to indicate and accumulate the minutes. In this embodiment, the first and second hands can be driven either by two completely independent motors or by a motor with two rotors but only a single stator and a single coil according to the above-mentioned document CH-B-675 940. This embodiment will now be explained with the help of the electrical sub-diagram of Figure 5.

This second embodiment comprises certain circuits equivalent to those appearing in the first embodiment. Thus, the chronograph comprises a first fifth-of-a-second counter 1 which is incremented by a time base signal of 5 Hz. The first hand thus advances by steps of a fifth of a second. It also comprises a second counter 3 which is incremented at each step of the first counter 10. The counter 10 is driven by a first control circuit 3 belonging to the same block 3 as that containing the second counter. The control circuit 3 is also driven by the time base signal of 5 Hz or by a high frequency signal of 32 Hz, depending on whether a first switch 7 is in a first position 60 for normal operation of the chronograph or in a second position 61. The diagram of Figure 5 also shows that the chronograph comprises a comparator 5 whose task is to compare the count of the first and second counters 1 and 3, in particular when the chronograph is in the stop function. The output signal of the comparator is equal to 1 when these counts are equal and equal to 0 in the opposite case. When the stop function is cancelled, the first switch 7 is in the second position 61 in order to accelerate the first hand 10. speed until the counts of the first and second counters are equal, the first hand then indicating the time it would have indicated if the stop function had not been activated, as explained with respect to the first embodiment.

The embodiment of Figure 5 differs from that of Figure 4 in that the circuit comprises a second switch 9 which can feed the control circuit 3 when the first switch 7 is in position 60, either by the 5 Hz time base signal when the second switch 9 is in the first position 70 (normal operation of the chronograph) or by a signal 54 when the second switch 9 is in the second position 71. Stopping the chronograph causes the switch 9 to flip over to position 71 and thus the feeding of the control circuit 3 by the signal 54 which is generated by the first counter 1 each time the latter has counted sixty seconds. It will therefore be understood that the first hand or central second hand 10 receives signals every minute when the chronograph is stopped and that, instead of being stopped as in the first embodiment, it moves by steps of one minute to form an hourly totalizer for a total of five hours.

As was already the case in the first embodiment, the diagram of Figure 5 shows that the minute counter 2, the comparator 6 and the switch 8 present in Figure 3 have been omitted, the block 4 containing only a second control circuit 4 without a second counter, which is directly controlled by the first counter 1 each time the latter has counted sixty seconds. In this version too, the minute totalizer (over thirty minutes) is normally activated when the chronograph is stopped.

Figure 1 and its enlarged part shown in Figure 2 show how the dials 53 and 55 of the chronograph are designed according to the second embodiment of the invention. The first hand or central second hand 10 rotates on the dial 53, which has second divisions 31 and fifth-second divisions 30 when the second hand is in normal operation. The seconds 31 are identified by inscriptions 15, 30, 45 and 60 carried towards the inside of the dial. When the chronograph is stopped, the second hand indicates 10 minutes. Thus, the division 41 (Figure 2) indicates a fifth of a second when the chronograph is in normal operation and a minute when it is stopped. Similarly, graduations 42, 43 and 44 indicate the second, third and fourth fifths of a second when the chronograph is in normal operation and the second, third and fourth minutes when it is stopped. Reference 31 (Figure 2) indicates one second and five minutes respectively. Reference 32 bears whole hour numbers: 1 to 5 hours, inscribed on the outside of dial 53. Second hand 20 rotates on a small dial 55 and indicates the minutes over thirty minutes, comprising thirty graduations 33, whether the chronograph is in normal operation or in the stop function.

When the chronograph of the second embodiment is stopped manually by means of the pusher 52, the first hand starts to strike the minute from any point and if this stop occurs at a time other than twelve o'clock, the hour divisions 32 do not correspond to reality. The hand 10 then only indicates that the chronograph is stopped and not stopped, with jumps occurring every minute. Since the stop function is already carried out by the second hand 20 is displayed, one can imagine stopping the first hand 10 if the stopping is done manually.

In order for the second hand 10 to be transformed into an hour totalizer corresponding to the 32 divisions of the dial, the chronograph must be equipped with an automatic stop system which is activated after a whole number of minutes, the first control circuit 3 being designed to make the second hand move a number of steps equal to this whole number from the automatic stop of the chronograph. For example, if the automatic stop is activated four minutes after the chronograph has started, the second hand, after completing four circuits around the dial to reach twelve o'clock, will advance four more divisions 30 to stop at division 44, from which the second hand advances by one step per minute. From that moment, the second hand will indicate the 32 hours inscribed on the dial.

Claims (6)

1. Electronic analog chronograph, comprising at least a first hand (10) which makes one revolution per minute and indicates seconds (31) or fractions of seconds (30) and is controlled by a first control circuit (3), and a second hand (20) which indicates and totals minutes (33) and is controlled by a second control circuit (4), which second hand moves one minute when the first has elapsed sixty seconds, and pushers (51, 52) which can be actuated by the user and by means of which the chronograph can be started, stopped, stopped and reset to zero, characterized in that means are provided for, when the chronograph is stopped, to allow at least the second hand (20) to continue to indicate and total the minutes (33) in order to indicate to the user that the chronograph is in operation and not stopped. 2. Chronograph according to claim 1, characterized in that the first hand (10) is stopped when the chronograph is stopped. 3. Chronograph according to claim 2, characterized in that it comprises: a first counter (1) for seconds, which is incremented by a time base signal (1 Hz, 5 Hz), a second counter (3) which is incremented at each step of the first hand (10), the latter being driven by a first control circuit (3) controlled by the time base signal or by a high frequency signal (32, 50 Hz), depending on whether a switch (7) is in a first position (60) for normal operation of the chronograph or in a second position (61), a comparator (5) which compares the count of the first (1) and second (3) counters when the chronograph is stopped, which comparator (5) sets the switch (7) in the second position (61) when the stop function is cancelled, to make the first hand (10) run at an accelerated speed until the counts of the first and second counters are equal, which first hand thus indicates the time it would have indicated if the stop function had not been switched on, and a second control circuit (4) for the second hand (20) which is controlled directly by the first counter (1) whenever the latter has counted sixty seconds. 4. Chronograph according to claim 1, characterized in that the first hand (10) moves by steps of a fifth of a second when the chronograph is functioning normally and by steps of a minute when it is stopped, in order to form an hour totalizer, the angular step of the first hand being the same for both functions. 5. Chronograph according to claim 4, characterized in that it comprises: a first counter (1) for fifths of a second, incremented by a time base signal (5 Hz), a second counter (3) which is incremented at each step of the first hand (10), the latter being driven by a first control circuit (3) controlled by the time base signal (5 Hz) or by a high frequency signal (32.50 Hz), depending on whether a first switch (7) is in a first position (60) for normal operation of the chronograph or in a second position (61), a comparator (5) which compares the count of the first (1) and second (3) counters when the chronograph is stopped, which comparator (5) brings the first switch (7) into the second position when the stop function is canceled in order to drive the first hand (10) at an accelerated speed; until the counts of the first and second counters are equal, which first hand thus indicates the time it would have indicated if the stop function had not been activated a second switch (9) enabling the first control circuit (3) to be fed either with the time base signal (5 Hz) during normal operation of the chronograph or with a signal (54) generated by the first counter (1) each time the latter has counted sixty seconds when the chronograph is stopped in order to make the first hand (10) the hour totalizer, and a second control circuit (4) of the second hand (20), directly controlled by the first counter (1) each time the latter has counted sixty seconds. 6. chronograph according to claim 5, characterized in that the chronograph is automatically stopped after a whole number of minutes after it is started, the first control circuit (3) being designed to make the first hand (10) run through a number of steps equal to this whole number from the time the chronograph is stopped.