HK1108944B - Reset mechanism for a timepiece - Google Patents

Description

The present invention relates to a reset device for a watch part, particularly for a chronograph.

In conventional chronographs, the reset of the hands of the seconds, minutes and hours is done by means of a push button, the actuation of which sets in motion a single-block piece with hammers which strike the heart-shaped reset cams mounted on the axes of the hands.

These reset devices have several drawbacks: they are relatively bulky because the stroke of the single-block workpiece must be large enough to allow the hammers to be out of the way of the cams in the rest position and to lean on the cams during reset; and due to manufacturing tolerances, the reset of minute and/or hour hands is generally not accurate, as the hammers cannot hit all three cams perfectly accurately; and hammers exert pressure on the reset cams which can be very strong, which can damage or even damage the axes of the wings.

CH 249 420 describes a reset device comprising a pusher that drives a lever that drives a hammer acting on two heart-shaped reset cams.

The present invention is intended to remedy at least part of the aforementioned disadvantages.

To this end, a reset device is provided for a watch part as defined in claim 1, a device for starting, stopping and resetting a chronograph as defined in claim 9 and a chronograph as defined in claim 13.

Further features and advantages of the present invention will be apparent from the following detailed description made by reference to the figure in the Appendix which represents a reset device according to a particular embodiment of the invention.

As shown in Figure 1, a chronograph reset device 1 according to the invention comprises a push button, schematically represented as 2, operated by a user, a lever 3 controlled by the push button 2, a sliding control 4 controlled by the lever 3, swivel hammers 5 controlled by the sliding organ 4 and heart-shaped reset cams 6 operated by the hammers 5 respectively.

Depending on the position of the push button 2, lever 3 can take a rest position shown in dotted lines and a reset position shown in full lines. Lever 3 is subjected to the action of a spring 7 booster which opposes the action of the push button 2. Lever 3 has, at one end, two pins 8, 9 between which is interposed with a certain play a 10 end of the sliding organ 4. In the rest position of lever 3, the pin 9 is in a butto against the 10 end of the sliding organ 4.

The sliding organ 4 has oblong openings 11 that cooperate with fixed guide pins 12 to allow organ 4 to slide in translation in the direction of the oblong openings 11 between a rest position shown in dotted lines and a reset position shown in full lines. Sliding organ 4 is subject to the action of an all-or-nothing spring 13, called reset jumper. The 14 end of this reset jumper 13 is aimed at a 15 angle defined by the slice of organ 4 when the latter is in the rest position, and rests against an inclined plane 16 of this slice when the slice of organ 4 is in its position of reset. This could, however, be removed in its variation 13.

Conventional reset cams 6 are heart shaped and mounted on the axes of chronograph hands, namely a seconds hand, a minute hand and a hour hand (not shown).

The axes or pivots 17 of hammer 5 such as the pivot 18 of lever 3 and the pins 12 are mounted on a fixed part of the chronograph such as the barrel bridge. The pivots 17 of hammer 5 are thus independent of the sliding organ 4, i.e. they remain fixed in translation when the sliding organ 4 is moved in one direction or the other. Each hammer 5 has, on one side of its pivot 17, a first arm 18, and on the other side of its pivot 17, the second and third arms 19, 20.

The first arm 18 is articulated by its end to the sliding organ 4 by means of a pin 21 cast into that end and which cooperates with a larger hole formed in the sliding organ 4. The reverse is of course also possible, namely that the pin 21 could be cast into the sliding organ 4 and cooperate with a larger hole formed in the arm 18. This articulation between the first arm 18 and the sliding organ 4 allows the sliding organ 4 to rotate the hammer 5 around its pivot 17 between a rest position where the hammer 5 is in the way of the corresponding cam 6 and a zero-back position where the percussion face of the hammer, referred to in shoulder 22, is resting on the cam 23 6.

The 22nd percussion face of each hammer 5 intended to cooperate with the corresponding cam 6 is defined by the stiff end of the second arm 19. This 22nd face is known to be inclined relative to the line passing through the respective pivots 17, 24 of hammer 5 and cam 6 when hammer 5 and cam 6 are in their reset position where face 22 is supporting the 23rd shoulder of cam 6.

The end 25 of the third arm 20 is free, and this end serves as a support against which the face 26 of the end of the second arm 19 opposite the percussion face 22 can be supported to limit the bending of the second arm 19, especially in cases where, during the reset movement of the hammer 5, the percussion face 22 comes into contact with the tip 27 of the cam 6.

Preferably, for each hammer 5, the distance or lever arm d1 between pivot 17 and the joint point to sliding organ 4, more precisely between the center of pivot 17 and the center of the joint pin 21, is shorter than the distance or lever arm d2 between pivot 17 and the percussion face 22, more precisely between the center of pivot 17 and the center of the percussion face 22.

The reset device 1 of the invention also cooperates with a vertical clutch 30 of the chronograph, which clutch allows, in a manner known in itself, the chronograph to start or stop by the action of a second push button (not shown) separate from the push button 2. This clutch 30 comprises a column wheel 31 actuated by the second push button, two clutches 32, 33 of which one 32 controls the other 33 and cooperates with the column wheel 31 by a nozzle 34, and two overlapping wheels, the lower 35 and upper 36 separated by a cone (not shown) on which the clutches 32 act.33 the lower wheel 35 being continuously driven by the clock movement of the chronograph, more precisely by the second wheel of the clock movement, the upper wheel 36 being driven by a chronograph wheel connected to the hands of the seconds, minutes and hours counter.In the closed position of the calipers 32, 33, the cone is in a high position which dissolidates the upper wheel 36 from the lower wheel 35 and the chronograph is therefore stopped.

In the present invention, the clamp 32 with the 34 pin may be controlled not only by the column wheel 31 but also by the lever 3. To this end, a third pin 37 is fitted at one end of the lever 3 other than the one carrying the two pins 8, 9 and the clamp 32 has a 38 pin and a 39 pin. In the resting position of the lever 3, the pin 37 is placed in the gap 38, near the wall of the lever, and does not interfere with the possible movements of the pins 32, 33 controlled by the column wheel 31. When the button 2 is actuated, the pin 37 pushes successively with a portion of the pin 40 from the 38 pin and with the 39 pin to close the pins 32, 33 and 39 directly, or cooperates with the pin 32 to maintain the function of the 33 pin in relation to the 34 pin, in the closed position of the column 31.

The reset by the device according to the invention is carried out as follows: when the user presses the push button 2, the user rotates the lever 3 from its rest position (dotted lines) to its reset position (full lines). During the first part of the stroke of the lever 3, the sliding organ 4 remains in the rest position due to the play between the pin 8 and the end 10 of the sliding organ 4, while the pin 37 of the lever 3 comes to slide over the portion of wall 40 of the gap 38 of the gripper 32 to gradually close the grippers 32.33 if they are not already closed by the cooperation of the beak 34 with the column wheel 31, and thus stop the chronograph. From the moment the pin 8 comes into contact with the end 10 of the sliding organ 4 begins a second part of the stroke of the lever 3 where the pin 8 pushes the sliding organ 4 in a direction that makes the hammers 5 rotate towards the cams 6 from their rest position, shown in dotted lines. However, this second part of the stroke of the lever 3 is only performed from a certain force on the push button 2 sufficient to defeat the action of the reset jumper 13,Once the action of this jumper 13 is defeated, hammers 5 come to strike the cams 6 in a frank manner and rotate them until the percussion face 22 of hammers 5 is supported against the shoulder 23 of cams 6, as depicted in full strokes. At the same time, pin 37 holds the pin 32, 33 closed by continuing its slide on the wall of the gap 38 until it reaches the beak 39.When the push button 2 is released, the lever 3 is brought back by its booster spring 7 into its resting position. During this movement, the pin 37 returns to its original position in clearance 38, which automatically restarts the chronograph or allows it to be restarted via the second push button depending on the position of the beak 34 relative to the column wheel 31, and the pin 9 of the lever 3 pushes the 10th end of the sliding organ 4 to bring the sliding organ 4 and hammers 5 back into their resting position.

It should be noted that, thanks to its sliding control 4 which rotates the hammers 5 around their pivots 17, the reset device according to the invention offers great flexibility in the choice of arrangement of the various elements, especially the hammers 5, which facilitates its integration into an additional movement or mechanism and reduces overall congestion. More specifically, the congestion of the reset device according to the invention can be significantly reduced by playing on the lever arms of the hammers 5, i.e. as in the illustrated example, by choosing a d1 lever arm that is smaller than the d2 lever arm.

The elasticity of the 19 arms of the hammer 5 is compensated for by the elasticity of the 19 arms of the hammer 5 which allows the three hands to be reset precisely, and this elasticity of the 19 arms reduces the stresses on the 24 pins of the hands during reset.

Finally, by stopping the movement of the chronograph hands before resetting them, the device according to the invention allows precise restarting of the chronograph hands after resetting and prevents the clockwork second wheel from going backwards by catching up the gears under the effect of clutch 30 friction during resetting, which would cause the chronograph hand to jump forward after resetting.

Although the present invention has a particular application in the reset of chronograph hands, it is not limited to such an application, as the present invention can be applied to any watch part in which one or more hands are desired to be reset.

Claims (14)

1. Zero-resetting device for a timepiece comprising a manual control organ (2), a second control organ (4) which is mobile in translation and may be actuated by the manual control organ (2), one or several zero-resetting cams (6) and one or several hammers (5) which may be actuated by the second control organ (4) so as to cooperate with the zero-resetting cam or cams (6), respectively, characterised in that the hammer or hammers (5) are pivoting about a respective pivot or pivots (17) that are independent of the second control organ (4), and are hinged to the second control organ (4) so that they may be pivoted about said pivot or pivots (17) by a translational movement of the second control organ (4).
2. Zero-resetting device according to claim 1, characterised in that it comprises several zero-resetting cams (6) and several respective hammers (5).
3. Zero-resetting device according to claim 1 or 2, characterised in that the cam or cams (6) are heart-shaped.
4. Zero-resetting device according to any one of claims 1 to 3, characterised in that the manual control organ (2) is a push-button.
5. Zero-resetting device according to any one of claims 1 to 4, characterised in that for the hammer or each hammer (5), the distance (d1) between the point (21) of hinging to the second control organ (4) and the pivot (17) is shorter than the distance (d2) between the face (22) that is intended to cooperate with the corresponding cam (6) and the pivot (17).
6. Zero-resetting device according to any one of claims 1 to 5, characterised in that the hammer or each hammer (5) comprises an elastic arm (19) one end of which defines the face (22) of the hammer (5) that is intended to cooperate with the corresponding cam (6).
7. Zero-resetting device according to claim 6, characterised in that the hammer or each hammer (5) comprises another arm (20) that is rigid, said end (22, 26) of the elastic arm (19) being able to rest against the end (25) of said other arm (20) in order to limit the deformation of the elastic arm (19) while the hammer (5) cooperates with the corresponding cam (6).
8. Zero-resetting device according to any one of claims 1 to 7, characterised in that it further comprises a control organ (3) intermediate between the manual control organ (2) and the second control organ (4).
9. Device for starting, stopping, and zero resetting of a chronograph, comprising a coupling device (30) and a zero-resetting device (1) according to claim 8, the intermediate control organ (3) of the zero-resetting device (1) being adapted to control the coupling device (30) so as to stop the chronograph, over a first segment of its excursion, and to control a translational displacement of the second control organ (4) for actuating the hammer or hammers (5), over a second segment of its excursion that follows the first segment.
10. Device according to claim 9, characterised in that the coupling device (30) is a vertical coupling device comprising clamps (32, 33), and in that the intermediate control organ (3) is adapted to control closing of the clamps (32, 33) over the first segment of its excursion.
11. Device according to claim 10, characterised in that the intermediate control organ (3) comprises, at a first end, first and second pins (8, 9) between which one end (10) of the second control organ (4) is inserted with play, and, at a second end, a third pin (37) cooperating with one (32) of the clamps (32, 33) that controls the other (33).
12. Device according to any one of claims 8 to 11, characterised in that the intermediate control organ (3) is a lever.
13. Chronograph comprising a device according to any one of claims 1 to 12.
14. Chronograph according to claim 13, characterised in that the zero-resetting cam or cams (6) comprise cams for zero-resetting a seconds counter hand, a minutes counter hand, and an hours counter hand.