EP2735919B1 - Watch movement comprising a fusee - Google Patents

Description

FIELD OF THE INVENTION

The present invention relates to a watch movement comprising a motor barrel, a rocket, movement winding means arranged to drive the rocket, a finishing gear train arranged to be driven by the rocket, and a chain, a rope or a wire of transmission stretched between the rocket and the barrel and arranged to unwind from the rocket and to wind on the barrel so that the barrel drives the finishing gear when the rocket rotates in a first direction, and arranged to unwind the barrel and to wind on the rocket so that the winding means arms the barrel when the rocket rotates in a second direction.

PRIOR ART

In the 15th century appeared clocks of relatively small dimensions that were actuated by a spring instead of the usual weight. These first spring clocks were significantly less accurate than the clocks driven by a weight suspended on a wire. Indeed, as is well known, the force exerted by a spring is not constant but decreases as the spring relaxes. However, the yard and foliage exhausts used at the time were extremely sensitive to variations in engine torque. The spring clocks therefore tended to slow down gradually as the power reserve ran out.

A very old solution to equalize the force provided by a barrel spring to the gear train is to use a rocket. The figures 1 and 2 annexed illustrate two traditional embodiments of a barrel coupled to a rocket. The figure 1 is a schematic sectional view of the entire wheel of a timepiece comprising a rocket. In this figure, the reference 2 generally indicates the barrel, 4 indicates the rocket, 6 is the chain stretched between the barrel and the rocket, 8 is the ferris wheel that a ratchet system (not shown) rotates in solidarity with the barrel. rocket in one direction, 10 is the axis of the rocket, and finally, 12 is a square formed on the axis of the rocket to allow reassembly. Referring now to the more detailed view of the figure 2 it can be seen that a rocket consists essentially of a conical shaped pulley whose throat winds in a spiral and which is connected to the engine cylinder by a chain. The chain is wound from the barrel on the rocket so that the smallest radius receives the greatest force. During the disarming of the mainspring, the chain winds progressively on the barrel by pulling on the rocket with a continuously increasing lever arm so as to compensate for the reduction of the spring force.

Referring again to the figure 1 it can be seen that the large wheel 8 is arranged to drive the center pinion 14 and then, in a conventional manner, the center wheel 16 meshes with the average pinion 18, that the average wheel 20 meshes with the second pinion 22, and finally, that the second wheel 24 meshes with the exhaust pinion 26. It can still be seen that the axis of the center wheel carries the roadway 28 and the gun of the hours 30. The roadway and the gun of the hours are connected to each other by the timer 32. We can also notice, as well on the figure 1 that the figure 2 , that the illustrated cylinder has no teeth. It will be understood that, the barrel being devoid of toothing, reassembly must be performed via the rocket. For this purpose, the known timepieces with rocket are usually equipped with a winding ratchet (not shown) which is integral with the axis of the rocket 4 via The pumping means are arranged to drive the rocket in rotation in the direction opposite to the direction of travel. As already mentioned, a ratchet system ensures disengagement of the large wheel 8 when the rocket rotates in the opposite direction of the direction of travel. Thus, the gear train is not driven in reverse during reassembly. On the other hand, the chain communicates the rotation of the rocket drum barrel, which has the effect of arming the spring.

The use of a rocket is a very effective solution to compensate for the variation of the spring force. In particular, the document CH 10599 describes a watch movement in which a rocket is provided between said movement and the barrel to compensate for the variation of the spring force. The gear ratio of the finishing gear is selected to maintain the operation of the movement by winding the spring only once a year. This mechanism, representing a certain size, is used in floor clocks or wall clocks. However, because of its conical shape, the rocket has a large footprint in the sense of height. It is therefore difficult to reconcile the use of a rocket with the requirements related to the design of a flat caliber. Efforts have been made to remedy this problem by producing lower rockets with a more compact shape. However, as shown in particular figure 2 , the direction from which the chain winds on the rocket must be perpendicular to the axis of rotation of the rocket. Under these conditions, it will be understood that the slope of the cone of the rocket can not be reduced below a certain threshold.

BRIEF SUMMARY OF THE INVENTION

An object of the present invention is therefore to overcome the disadvantages of the prior art which have just been described, and in particular to overcome the constraint of a minimum threshold for the slope of the cone of the rocket. The present invention achieves this goal by providing a watch movement comprising a motor barrel and a rocket and according to the appended claim 1.

According to the invention, a roller is slidably mounted on a fixed guide oriented in the direction of the axis of the rocket parallel to the main surface thereof. Due to the presence of the roller, the wire changes direction when approaching the rocket. So, instead of Wrap and unroll perpendicular to the axis of rotation of the rocket, the wire wraps and unrolls the rocket perpendicular to the orientation of the fixed guide.

According to an advantageous variant of the invention, the rocket does not have the shape of a cone, but that of a plate, the main surface of the rocket being flat. An advantage of this variant is to limit the height of the rocket as much as possible.

According to another advantageous variant of the invention, the roller comprises a pulley whose rim has a groove arranged to receive the wire, while the two side edges of the rim are arranged to roll on the bottom of the groove by enclosing the groove. thread.

BRIEF DESCRIPTION OF THE FIGURES

• la figure 1 est une vue schématique en coupe du rouage d'une pièce d'horlogerie de l'art antérieur comportant une fusée ;
• la figure 2 est une vue en perspective montrant la chaîne tendue entre le barillet lisse et la fusée d'une pièce d'horlogerie de l'art antérieur ;
• la figure 3 est une vue partielle en perspective montrant le barillet moteur et la fusée d'un mouvement de montre conforme à un premier mode de réalisation de l'invention;
• la figure 4 est une vue en plan de dessus montrant le barillet moteur et la fusée de la figure 3 ;
• la figure 5 est une vue en élévation du barillet moteur et de la fusée des figures 3 et 4 ;
• la figure 6 est une vue partielle en plan de dessus montrant le barillet moteur et la fusée d'un mouvement de montre conforme à un deuxième mode de réalisation de l'invention ;
• la figure 7 est une vue en coupe selon A-A de la figure 6.

Other features and advantages of the present invention will appear on reading the following description, given solely by way of non-limiting example, and with reference to the appended drawings in which:

• the figure 1 is a schematic sectional view of the wheel of a timepiece of the prior art comprising a rocket;
• the figure 2 is a perspective view showing the chain stretched between the smooth cylinder and the rocket of a timepiece of the prior art;
• the figure 3 is a partial perspective view showing the engine cylinder and the rocket of a watch movement according to a first embodiment of the invention;
• the figure 4 is a top plan view showing the engine cylinder and the rocket of the figure 3 ;
• the figure 5 is an elevational view of the engine cylinder and rocket figures 3 and 4 ;
• the figure 6 is a partial plan view showing the engine cylinder and the rocket of a watch movement according to a second embodiment of the invention;
• the figure 7 is a sectional view according to AA of the figure 6 .

DETAILED DESCRIPTION OF EMBODIMENTS

The figures 3 , 4 and 5 are three views, respectively in perspective and in plan from above and from the side, of a first embodiment of the invention. It is recognized in the figures a barrel 102, which is housed a barrel spring (not shown), and a rocket 104 which is connected to the barrel by a wire 106.

In a manner known per se, the barrel is formed of a barrel drum 142 which serves as a housing for the spring, a barrel cover 144 which closes the box formed by the drum, and a barrel shaft (not shown ) which passes through the barrel and which is fixed at its ends to the plate and a bridge. The barrel shaft acts as a pivot for the barrel. The spring is hooked by one end to the shaft, and the other to the drum. When armed, the spring is wound against the circumference of the shaft. By seeking to return to its original form, the spring is unwound by rotating the barrel. The cylinder 102 is kinematically connected to the rest of the movement by the wire 106. It therefore does not need toothing. This is called a smooth cylinder.

The wire 106 is stretched between the barrel 102 and the rocket 104 so as to transmit the rotational movement of the barrel to the rocket and vice versa. The rocket 104 is generally in the form of a plate with a planar upper surface in which is formed a spiral groove 148 concentric with the axis of the rocket. At the periphery of the rocket, the groove opens on a notch 150 inside which is formed a through hole (not shown). One end of the wire 106 is inserted and fixed in the through hole. The wire is wound in the groove from the notch 150 so that the distance between the wire and the axis of the rocket 104 decreases as one moves away from the end of the wire. When the spring relaxes by rotating the barrel 102, the wire wraps around the barrel by driving the rocket. As the wire is spirally wound on the rocket, it will be understood that the barrel pulls the rocket with a lever arm that increases as the wire unwinds. Thus, when the spring force is the smallest, the distance between the axis of the rocket and the point of application of the force is the largest. The reduction of the spring force can therefore be compensated.

As can be seen on the figure 5 and more in detail about the cut of the figure 7 a large wheel 180 whose teeth meshes with the center pinion of the watch (referenced 200) is arranged coaxially with the rocket 104. The big wheel and the rocket are mounted idle on both ends of the same referenced shaft 182. It can also be seen that a planetary gear is interposed between the ferris wheel and the rocket. The planet gear comprises a pinion 184 integral with the shaft 182, a ring gear 186 which is driven concentrically on the base of the rocket, and a satellite wheel consisting of a wheel 188 and a pinion 190 pivoted in an eccentric position on the board of the ferris wheel 180. A winding ratchet 192 is also driven on the lower end of the shaft 182. In a manner known per se, a pawl (not shown) is still provided to prevent the ratchet to turn in a first direction of rotation.

The operation of the planet gear is as follows. During disarming, the spring relaxes and rotates the barrel 102. The wire 106 is progressively transferred from the rocket to the barrel by driving the rocket 104 in the first direction of rotation. The sawtooth profile of the winding ratchet has the effect of retaining the shaft 182 which can not rotate with the rocket. The rocket drives the pinion 190 of the mobile satellite via the ring 186. The wheel 188 of the satellite mobile meshes with the pinion 184 in solidarity with the shaft 182. Under these conditions, when the rocket rotates in the first direction, the satellite mobile is driven by the ring 186. As the pinion 184 is prevented from rotating by the ratchet, the satellite revolves around the shaft 182 in the opposite direction of the rocket, and drives the big wheel 180 with him. The big wheel drives in turn the center pinion and through it all the finishing gear.

The watch movement which is the subject of the present description usually comprises means for winding the movement (not shown). These winding means are arranged to drive the winding ratchet 192 in the second direction of rotation. When the winding ratchet is actuated, it rotates the pinion 184 which it is secured. The pinion 184 engages with the wheel 188 of the satellite mobile and drives the latter in the first direction of rotation. The pinion 190 of the mobile satellite meshes with the ring gear 186 of the rocket. Note that the large wheel 180 can rotate in the second direction of rotation only. Indeed, in known manner, the finishing gear is associated with a second ratchet mechanism (not shown) which prevents any rotation of the train in the opposite direction to the direction of movement. Under these conditions, it will be understood that this blocking of the large wheel 180 prevents the satellite mobile from rotating around the shaft 182 in the first direction of rotation. It is therefore the rocket that is driven in the second direction of rotation by the satellite mobile via the ring 186. It will be understood that, when the rocket thus rotates in the second direction of rotation, the wire 106 is progressively transferred from the barrel 102 to the rocket 104 by driving the barrel in the direction of rotation corresponding to the winding of the spring.

A general characteristic of rockets is that the wire is wound on a surface of revolution that is not parallel to the axis of rotation of the rocket. This is why a spiral groove is almost always needed to guide the wire. In the case of a flat rocket like described in this example, the surface on which the wire is wound is even perpendicular to the axis of rotation of the rocket. Under these conditions, even the presence of a groove is not sufficient to guide the wire so that it winds regularly on the rocket. This is the reason why, according to the invention, the watch movement comprises, in addition to the rocket, a fixed guide (referenced 155) and a roller (referenced 157) provided for guided the wire 106 and which is mounted sliding on the fixed guide.

According to the invention, the guide for the roller retractor is oriented parallel to the main surface of the rocket and in the direction of the axis of the rocket. In other words, in the case where the shape of the rocket is substantially that of a cone of revolution as in the prior art, the guide according to the invention is oriented to allow the roller roller to slide parallel to a generator of the cone. On the other hand, if, as in the illustrated example, the shape of the rocket 104 and substantially that of a disk, then the guide 155 is oriented horizontally, parallel to a radius of the disk. With particular reference to the figure 4 it can be seen that, in the illustrated embodiment, the roller 157 has the shape of a thin pulley, and the guide 155 is constituted by a cylindrical shaft. The pulley is rotatably mounted on the shaft 157 and, as already mentioned, it is also arranged to slide transversely along the shaft. The diameter of the pulley is such that its rim penetrates into the spiral groove 148. When the rocket 104 rotates, the pulley 157 is guided by the edges of the groove, so that it traverses the groove by shifting laterally along the groove. of the tree 155.

When the wire 106 is wound on the barrel 102, it is released from the rocket 104. Conversely, when the wire is unwound from the barrel, it winds in the spiral groove 148. The introduction of the wire into the groove, as its extraction from it, is provided by the pulley 157. For this purpose, the pulley has a groove around its periphery. This throat is arranged to receive and guide the thread. The peripheral portion of the pulley is shaped to penetrate the spiral groove, so that through the pulley, the wire is passed under it, so as to be sandwiched between the bottom of the groove and the throat of the pulley.

As mentioned above, one of the aims of the present invention is to reduce the size associated with a rocket. It will therefore be understood that it is advantageous to use a wire whose thickness is as small as possible. Indeed, if the wire is thinner, the spiral groove can also be narrower. At present, there is on the market a choice of extremely fine son. The diameter of these new generation wires is between a few tens and a few hundred microns. Even finer threads, made for example with nanotubes already exist in the laboratory. According to the embodiment of the invention which is the subject of this example, the wire wound on the barrel and the rocket to be a wire of a thickness of about 100 microns marketed by Berkley® under the name Nanofil®. It will be understood that with such a fine wire, it is possible in particular to use a roller 157 very small roller. This roller can be made for example in sapphire in the manner of a stone with hole. In this case, the roller may take the form of a thin disk with a groove around its periphery and a hole arranged in its center for the guide 155.

The Figures 6 and 7 illustrate an engine cylinder and a rocket implemented in a second embodiment of the invention. As will be seen in more detail below, in this second embodiment, the reel roller also fulfills the function of power reserve indicator. Notwithstanding this difference, the second embodiment is very similar to the previous one. This is the reason why the elements of the figures which are identical in the two embodiments are designated by the same reference numerals in the figures.

With particular reference to the figure 6 it can be seen that the axis 102 of the rocket is pivoted in bearing 265 carried by a bridge 263. This bridge also carries the guide for the roller roller. This guide is constituted by a shaft 255 suspended by its two ends at the bridge 263. The bridge 263 still has a rectangular opening through which it is possible to see the guide 255 and the roller roller 257. In the example shown, the roller retractor is associated with a jumper 259 provided with an index 261. The jumper 259, which is integral in translation of the retractor roller, is visible through the rectangular opening in the bridge. The index 261 always indicates the position of the roller, and the bridge 263 still carries a graduated scale arranged opposite the rectangular opening. The end of the index is arranged to cooperate with the scale to indicate the power reserve.

It will be further understood that various modifications and / or improvements obvious to those skilled in the art can be made to the embodiments which are the subject of the present description without departing from the scope of the present invention defined by the appended claims. In particular, the roller pulley is not necessarily constituted by a pulley rotatably mounted on an axis. Indeed, the wire could very well be arranged to slide in the throat of the roller without the latter is to turn on itself.

Claims (4)

1. Watch movement comprising a barrel (102) having a barrel drum (142), a barrel arbor and a spring accommodated in the barrel drum, said spring being held between said arbor and said drum, wherein the movement additionally comprises a fusee (104) arranged to rotate in a first direction and in a second direction and having a main surface, which has a spiral groove (148) concentric to the axis of the fusee, a winding mechanism (192) arranged to rotate the fusee, a going train (200) arranged to be driven by the fusee and a transmission wire (106) extended between the fusee and the barrel, one of the ends of the wire being wound into the spiral groove, and the wire being arranged to unwind from the spiral groove of the fusee and to wind up onto the barrel so that the barrel drives the going train when the fusee rotates in the first direction and being arranged to unwind from the barrel and to wind onto the fusee guided by the spiral groove so that the winding mechanism winds the spring when the fusee rotates in the second direction, characterized in that the watch movement comprises a fixed guide (155; 255) and a winding roller (157; 257) mounted to slide on the fixed guide and arranged to guide the wire (106) between the barrel and the fusee, wherein the fixed guide is oriented in the direction of the axis of the fusee parallel to the main surface of the fusee, and the winding roller is arranged to slide on the guide transversely to the wire while being engaged in the spiral groove in order to pass through the groove, extracting the wire therefrom when the fusee rotates in the first direction and inserting the wire therein when the fusee rotates in the second direction.
2. Watch movement according to claim 1, characterized in that the winding roller (157; 257) comprises a pulley having an edge arranged to penetrate into the spiral groove (147) and having a peripheral groove arranged to guide the wire (106).
3. Watch movement according to claim 1 or 2, characterized in that the main surface of the fusee (104) is plane.
4. Watch movement according to one of claims 1, 2 or 3, characterized in that the winding roller (257) is fixed against translation movement to an index (261) arranged to cooperate with a fixed scale oriented parallel to the fixed guide (255) in order to indicate the power reserve.

Images