Timekeeper with a mechanism for measuring settable predetermined periods

This timekeeper comprises a first timer (4), means (12) for connecting it selectively to the train of the timekeeper (T), a second timer (5), a synchronous coupling between the first (4) and second (5) timers, and fly-back means (13, 13′, 9, 11) for said timers (4, 5). An auxiliary motive source (10′) is in a driving relationship with the second timer (5) and a one-way coupling (6a, 7a) is situated between the first (4) and second (5) timers to regulate the speed of movement of the latter at a predetermined ratio with the speed of movement of the first timer (4) while allowing one-way relative movement of the first timer (4) relative to the second (5) when the latter is in the stop position and one-way relative movement in the opposite sense of the second timer (5) when the first timer (4) is in the stop position.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority of European Application No. 05405596.7 filed Oct. 21, 2005, which is incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a timekeeper with a mechanism for measuring settable predetermined periods, comprising a first timer, means for connecting it selectively to the train of the timekeeper, a second timer, a synchronous coupling between the first and second timers, and fly-back means for said timers.

2. Description of the Related Art

Timers of this kind are used particularly for controlling the starts of regattas where the competitors are warned a few minutes in advance of the start time by a gun. A second gun is also fired halfway through the period between the first gun and the third gun which will give the start. This second gun gives competitors the chance to check whether they are synchronized with the official time. This period is usually ten or six minutes so the second gun is fired at exactly the halfway mark, at five or three minutes, respectively.

A timer of this kind has already been proposed in CH 692 523. It has apertures in the dial and a disk having sectors of different colors which appear under the apertures and move as the period is measured. Such a device gives no indication of seconds and cannot be corrected if the timer was not started at the right instant, nor can the countdown time be programmed.

Another proposal, given in WO 02/077725, is a chronograph mechanism capable of operating either in the conventional direct sense, or in the retrograde sense for a countdown. Such a mechanism does not however offer a way of resetting the timer, specifically at the second gun fired before the start of a regatta. In the event of a false start it offers no way of storing the previously programmed period, and after each measurement of a predetermined period has to be reset for the next period to be measured, even if the latter is identical to the previous period.

What is more, with this timer, at the end of the measured predetermined period, the minutes timer does not stop at zero but continues its retrograde movement until stopped.

As can be seen, the systems proposed hitherto all have a number of drawbacks.

BRIEF SUMMARY OF THE INVENTION

It is an object of the present invention at least partly to remedy these drawbacks.

To this end, the subject of the present invention is a timekeeper with a mechanism for measuring a settable predetermined period as claimed in claim1.

By virtue of its design, the timekeeper according to the invention allows the measured period to be programmed and the programmed period to be stored at each fly-back as long as this program has not been modified. The timing mechanism can be resynchronized by a user action, from an external time base at any time during the measurement of the predetermined period. This facility is important because it means that any error made when starting to measure the predetermined period can be corrected, whether to correct a delay or an anticipation. This resynchronizing facility has the advantage that the timer can be resynchronized exactly on the second gun preceding the start of a regatta.

Advantageously, the second timer, which is preferably the minutes timer, is stopped at the end of the measured predetermined period, while the first timer, which is preferably the seconds timer, continues moving until stopped. This makes it possible for example to measure how much time has passed since the start of the regatta.

Other features and advantages will become apparent in the course of the following description of two embodiments of the timekeeper illustrated schematically and by way of example in the attached drawings.

DETAILED DESCRIPTION OF THE INVENTION

Upon examination, the second embodiment will be seen to be relatively complex since its mechanism is divided between the two sides of the timekeeper. It was therefore felt advisable to begin by describing the invention with the aid of a simplified version which will facilitate an understanding of the inventive concept.

The mechanism shown inFIG. 1comprises a control stem1fixed to an actuating crown1′ which rotates, much like a winding stem, and two pushers2and3. The pusher2is able to engage with the ratchet teeth of a column wheel8through an intermediate click lever14and is used to start and stop the timer mechanism. The pusher3is for resetting and resynchronizing the wheels and pinions of the timers4and5on which the seconds hand4′ and minutes hand5′ are mounted, respectively. The action of the pusher3is transmitted to two fly-back cams11,9by two fly-back levers13,13′, respectively. The lever13′ is pivoted to the lever13and is in engagement with a sliding member13apressed against the column wheel8by a spring13b, for a purpose which will be explained later. It should be observed that the fly-back cam9must be shaped in such a way that the pressure exerted by the lever13′ during resetting always causes it to turn in the sense S1for a reason which will be explained later.

The wheel and pinion4of the first or seconds timer4′ meshes on the one hand with a wheel and pinion11′ fixed to the fly-back cam11and on the other hand with a wheel and pinion16whose pinion meshes with a wheel7mounted freely on the arbor6′ of a wheel6and of a snail cam6″ which are both fixed to this arbor6′, which is in turn fixed to a one-way coupling element6aconcentric with a one-way coupling element7afixed to the wheel7. Balls7′ are arranged between these one-way coupling elements6a,7awhich are so shaped that, in the rotational sense S1of the arbor6′ and of the one-way coupling element6a, this arbor6′ is coupled in rotation to the wheel7. On the other hand, when the wheel7turns in the sense S2, it is the wheel7which drives the arbor6′. The utility of this one-way drive will be explained later. When the arbor6′ and the one-way coupling element6aare turning in the sense of rotation S2, they are uncoupled from the wheel7, and the latter can turn freely in the sense S1relative to the arbor6′.

The wheel and pinion5of the second or minutes counter, which is a hand5′ and a graduation (not shown), is in engagement with the toothed sector of a rack lever10pressed against the snail cam6″ by a spring10′, via a roller10″ that transmits the pressure of the spring10′ to this snail cam64″, creating a torque tending to turn both it and the wheel6which is also fixed to the arbor6′, in the sense S1. This wheel6meshes with a setting wheel9″ that is connected to the fly-back cam9fixed to a star wheel9apositioned by a click9′, allowing the angular position of the setting wheel9″ to be modified relative to that of the fly-back cam9, in increments of one step of the star wheel9a, when the latter is immobilized by the lever13′. For this purpose, this setting wheel9″ meshes with a connecting wheel15through an intermediate reverser pinion15′ which is pivoted freely on a rocker and makes it possible to transmit the rotation of the connecting wheel15to the wheel9″ only when this reverser pinion15′ is turning in the sense S2. This rotation is controlled by the hand-controlled stem1through a pinion (not shown) coaxial with and fixed to this stem1and having end-on teeth like those of a clutch pinion. The pitch of the teeth of the star wheel9afor setting the period to be measured corresponds preferably to one minute of the minutes timer5.

Angular movement of this setting wheel9″ in the sense S1relative to the fly-back cam9is transmitted to the snail cam6″ which turns in the sense S2and transmits this movement to the hand5′ of the minutes timer5which is driven in the sense S2by the rack lever10which, when raised by the snail cam6″, turns in the sense S1. It should be observed that this setting can only be done by turning the wheels and pinions of the setting mechanism of the minutes timer5in the sense indicated above, because of the one-way drive device between the wheels6and7. This is due to the fact that, since the actions of the two levers13,13′ are simultaneous, the train of the first or seconds timer4is immobilized, so that the wheel7is also immobilized, allowing the one-way coupling element6afixed to the wheel6and snail cam6″ to move only in the sense S2.

For the same reason, the minutes timer5can only be made to fly back by turning the snail cam6″ in the sense S2. To achieve this objective, the setting wheel9″ has a larger diameter than the wheel6, in order to optimize, in energy terms, the design of the fly-back cam9.

The selective connection between the timer mechanism and the train (not shown) of the timekeeper T which is used to drive this timer is made possible by a known type of clutch device12formed by two axially mobile circular elements and a spring12′ that tends constantly to get them to bite together. This clutch device is controlled partly by a lever26applied by a spring26′ against the columns of the column wheel8and partly by a protrusion13con the lever13. The lever26and the protrusion13cboth act against the force of the clutch spring12′ to separate the circular elements of the clutch12from each other.

Although the essential object of the timer mechanism according to the invention is to time predetermined settable periods, particularly for measuring the time running up to the start of an event, more particularly the start of a regatta, it is perfectly possible for this mechanism to continue measuring time after the start of the regatta.

For this purpose, the wheel11′ connected selectively to the train of the timekeeper T by the clutch12is fixed to a disk having a drive protrusion25. In addition, the arbor6′ fixed to the wheel6and to the snail cam6″ is fixed to a disk20containing a recess20′ whose angular position is adjusted to coincide with the stop position of the second timer5. One end21″ of a lever21is pushed by a spring21′ against the edge of the disk20. This lever21pivots on the arbor of a wheel22of an auxiliary minutes timer and carries a pinion24meshing with the wheel22. A jumper23serves to position this wheel22. When the recess20′ of the disk20arrives in front of the end21″ of the lever21, the latter pivots in the sense S1, allowing the protrusion on the disk25to drive the pinion24and the wheel22of the minutes timer one step in every revolution, i.e. every 60 seconds, given that the wheel11′ has a ratio of 1:1 with the wheel4of the seconds timer.

During programming, the timer mechanism described above requires that the pusher3be kept depressed as will be seen later. Advantageously, in order to avoid having to use both hands simultaneously which would mean having to remove the watch from one's wrist, a device for temporarily locking the pusher3is provided. This device is illustrated inFIGS. 8 and 9. As can be seen in these figures, the pusher3is held normally in the position illustrated inFIG. 8by a spring3a. It will also be seen that a piston27slides inside a ring28attached to a rotating bezel29of known type mounted on the watch middle30. This piston27is pressed against the pusher3by a spring31. The pusher3has a gap3b, so that when it is pushed towards the interior of the case and the rotating bezel29has first been moved into the angular position illustrated inFIGS. 8 and 9where the axis of the piston27intersects the axis of the pusher3, the piston27is pushed into the gap3bby the spring31. To remove it, the bezel29is simply returned to its initial angular piston, whereupon the piston27releases the pusher3.

When the bezel29is in the angular position shown inFIG. 10, allowing the pusher3to be locked, it simultaneously allows the pusher2to be disabled, which saves the user from pressing the wrong pusher and starting the timer instead of setting the period he or she wishes to measure. For this purpose the ring28fixed to the rotating bezel27has a semi-annular projection28awhich, when the rotating bezel27is turned to lock the pusher3in the depressed position, enters a gap2ain the pusher2, preventing it from being actuated.

As will have been seen in the course of the above description, because the measuring mechanism measures a settable predetermined time period, the minutes hand indicates the total period to be measured and, once started, at all times therefore indicates how much time is remaining to the end of the measured period.

Operating the mechanism described above involves a number of steps, namely: setting the period to be measured, starting the mechanism, resetting or resynchronizing during operation, stopping the mechanism, and causing the timers4and5to fly back.

In order to set the period to be measured, the user must first turn the rotating bezel29of the case to the position shown inFIGS. 8,9and10, in which the start/stop control pusher2is disabled. He then depresses the resetting and resynchronizing pusher3to get it into the position shown inFIGS. 1 and 10, in which it is retained by the piston27and in which the levers13and13′ prevent the fly-back cams11and9from turning. He must then rotate the control stem1by means of the crown1′ in the sense S3to bring about a relative movement of the setting wheel9″ in the sense S1relative to the fly-back cam9. Since, as explained above, the period can only be set by turning the snail cam6″ in the sense S2, then if it is wished to reduce the period to be measured from 10 to 6 minutes, for example, assuming 10 minutes to be the maximum settable predetermined period, the roller10″ of the rack lever10must be moved from 10 minutes to 0 minutes and then incremented until the hand5′ is pointing at the division corresponding to 6 minutes. The reverse is not possible because of the snail shape of the cam6″ and because the one-way drive wheel7is locked by the lever13engaging with the fly-back cam11fixed to the wheel11′ in a positively controlled relationship with the wheel7, which does not allow the one-way coupling element6afixed to the snail cam6″ and to the wheel6to rotate in any sense except the sense S2.

The timer having thus been set, it is started by returning the rotating bezel29of the case to its inactive position. This has the effect of releasing the pushers2and3and the fly-back cams9and11. The pusher2is depressed, which turns the column wheel8one step through the click lever14. The column wheel8releases the lever26which allows the clutch device12to connect the train of the timer to that of the timekeeper T. The freewheel7synchronizes the timer5under the force of the spring10′ with the speed of rotation of the train of the timer in a kinematic coupling with the timekeeper train. For its part, the force exerted by the spring10′ on the wheel6and on the one-way coupling element6asimultaneously keeps the timer train under tension and prevents floating of the hands resulting from the clearance of a gear that is not under tension. Moreover, the force necessary to tension this spring10′ is not taken from the barrel spring of the timekeeper: instead, this spring is tensioned by hand every time the timers4,5are caused to fly back.

Consequently the mechanism which measures the predetermined period is driven by the relaxing of the spring10′ which returns the stored energy without using the energy of the barrel spring of the timekeeper.

In the countdown to the start of a regatta, the first gun is usually fired 10 minutes and in some cases 6 minutes before the start and the second gun is fired halfway through the countdown, i.e. at 5 minutes or 3 minutes, respectively, before the third gun which indicates the start. It is often difficult to start the timer exactly on the first gun because the user does not know exactly when it will be fired. However, the competitor can much more easily anticipate the moment when the second gun is to be fired because he knows that it is five minutes, or three minutes, respectively, after the first gun. At this time he can read the difference between the start of his timer and the second gun to work out how many seconds before or after the gun he started his timer.

The measuring mechanism of the timekeeper according to the present invention solves this problem by making it possible to resynchronize the timer while measuring. This new function is explained with reference toFIG. 4. When the timer is started, the column wheel8rises and disables the lever13′ as illustrated in thisFIG. 4. When the pusher3is depressed, the lever13causes the hand4′ of the first or seconds timer to fly back, causing the hand5′ of the second or minutes timer to return to the nearest whole minute. As long as the pusher3is kept depressed, the countdown is put on hold, and starts again when the pusher3is released. This means that the pusher can be depressed a matter of tens of seconds before the second gun and released at the precise instant the second gun goes off. In the example illustrated, with a symmetrical heart-shaped cam11, the instant when the pusher3is actuated should not however be more than 30 seconds before the minutes timer5arrives at the whole minute at which the second gun is due to be fired, otherwise it will be returned to the minute preceding that at which the second gun is due, with the result that, when the pusher3is released on the gun, the minutes timer5would be one minute behind. The user can also briefly depress the pusher3at the precise instant of the second gun. Since the lever13′ is disabled, only the lever13strikes the cam11fixed to the wheel11′. At the same time, the protrusion13copens the clutch device12and thus allows the seconds timer4to be reset. The user releases the pressure on the pusher3to allow the timers4,5to resume their countdown.

If the fly-back of the seconds timer4involves a virtually instantaneous movement of the wheel11′ in the sense S2, the wheel7is moved virtually instantaneously in the sense S1through an angle proportional to the gear ratio. Because of the one-way coupling between the wheel7and the wheel6and because of the torque exerted on the wheel6in the sense S1by the spring10′, the wheel6follows the virtually instantaneous movement of the wheel7and thus corrects the position of the minutes hand5′. If the seconds counter is corrected by a virtually instantaneous movement of the wheel11′ in the sense S1, the wheel7is moved in the sense S2, i.e. it reverses compared with its normal direction of movement. Because of the one-way drive between this wheel7and the wheel6, the wheel6is also driven in the sense S2against the torque exerted by the spring10′ so that the rack lever10is caused to rise around the cam6″ and turn the minutes hand5′ in the sense S2.

When the minutes hand5′ reaches the end of the measured period, the roller10″ of the rack lever10is stopped by the radial face of the snail cam6″, asFIG. 3shows; but the seconds hand4′ can continue its normal course because of the one-way coupling between the wheels6and7. At the precise instant at which the snail cam6″ stops, the end21″ of the lever21drops into the recess20′ of the disk20, engaging the connecting wheel24with the drive protrusion25fixed to the wheel11′, allowing the auxiliary minutes timer22and the seconds timer4to measure the time that elapses after the end of the selected predetermined period, which was measured by the first or minutes timer5.

The timer is stopped by pushing the start/stop pusher2which turns the column wheel8, opens the clutch device12, and stops the timers4and22. The timers4,5and22are made to fly back by means of the pusher3and levers13,13′. The fly-back lever for the auxiliary minutes timer22has not been shown, but consists of a third arm connected to the other two fly-back levers. It should be pointed out that the selected period to be measured is retrieved automatically by fly-back. If this period is to be changed, the user simply performs the corresponding operation mentioned above.

The embodiment shown inFIGS. 5-7is a practical realization of the principle illustrated inFIGS. 1-4. To simplify the reading, all parts in this embodiment (FIGS. 5-7) that have the same functions as in the previous embodiment have the same reference symbols. Notice that this second embodiment has no auxiliary minutes timer.

As can be seen in the cross section inFIG. 7, the mechanism for timing a selected period is designed so that its parts can be arranged on the bridge side and on the dial side, with the watch movement T between them.

Some parts, notably the clutch12and the wheels11,4,16and7, are situated on the bridge side, while the rack lever10, the wheel6, the snail cam6″ and the pinion of the minutes timer5are situated on the dial side. The column wheel8and the levers13,13′ are on both sides of the movement. The arbor6′ connecting the wheel6to the one-way coupling element6aworking with the wheel7also extends through the movement. It will also be seen that the arbor of the pinion of the seconds timer4is coaxial with the pinion of the minutes timer5, which makes it possible to read the minutes and the seconds on the same dial.

The one-way coupling device between the wheels6and7of this embodiment differs from that of the first embodiment essentially in that it comprises a ratchet-toothed pinion7afixed to the wheel7and engaging with a click6bpivoting on a disk6afixed to the arbor6′ and to the wheel6. Although realized slightly differently from the first embodiment, the principle of the one-way coupling is identical.