EP3218770B1 - Motor member for a clock movement - Google Patents

Description

Field of the invention

The invention relates to the field of timepieces, and more specifically a motor of a watch movement to accumulate and restore the energy necessary for the movement.

The invention also relates to a movement and a timepiece equipped with such a motor member.

Background of the invention

In a conventional manner, a driving member for a timepiece consists of a barrel formed by a circular toothed disc and a drum closed by a cover. The barrel rotates freely on a shaft and receives a spring, generally formed of a ribbon wound on itself in a spiral around the barrel shaft, to which it is hooked by an inner coil through a bung, the outer turn being secured to the barrel drum in a fixed manner or in the form of friction.

Some barrels are built without lids to gain thickness. However, in such barrels, the spring may tend to come out of the drum and come into contact with an element of the movement of the watch, such as a ratchet for example. This contact interferes with the proper functioning of the watch by creating friction and consequently variations and losses of torque.

To overcome this drawback, some constructions implement a drum with an inner face having a conical surface to constrain the spring towards the bottom of the barrel. It appears that this constraint is not sufficient in the case of barrels having large diameters or having high torques.

The document DE 19 05 046 discloses a barrel for a clockwork movement, the barrel comprising a drum closed by a lid, the drum receiving a spring provided with a sliding flange. The drum has on its inner circular wall a shoulder configured to receive the sliding flange.

The document US 2,880,570 also described a barrel comprising a drum closed by a cover and receiving a motor spring provided with a sliding flange. The drum also has on its inner circular wall a shoulder configured to receive the sliding flange.

In these documents of the prior art only the flange is housed in a shoulder, which does not allow a correct axial retention of the spring, especially when it is in motion. In addition, these two documents describe a drum with a lid, which increases their thickness and makes it difficult to use them in so-called compact movements.

Summary of the invention

An object of the present invention is to overcome all or part of the disadvantages mentioned above by providing a motor member for axially maintaining the spring in the barrel regardless of the type of barrel.

More specifically, an object of the invention is to provide a spring having good axial retention within the barrel.

The invention also aims, at least in a particular embodiment, to provide a drive member which is simple to implement and inexpensive.

Another object of the invention is to provide a compact drive member to maintain the spring in the barrel and also to reduce the thickness of the watch movement.

For this purpose, the invention relates to a motor unit for a watch movement provided with a barrel comprising a drum, and at least one spring, the spring being wound inside the barrel, the inner coil of the spring being coupled to a bung, and the outer coil of the spring being in contact with the circular wall of the drum.

According to the invention, the drum comprises on its inner circular wall axial retention means of the spring in the form of a peripheral groove, and the spring comprises complementary holding means configured to cooperate with the axial holding means so as to maintain the spring axially within the barrel.

Thanks to these characteristics, such a motor unit for a clockwork movement makes it possible to improve the stability of the torque provided by the barrel as well as the efficiency of the barrel, the axial retention of the spring in the barrel preventing the spring from coming out of the drum and of come into contact with an element of the drive member, typically the cover or the ratchet.

• les moyens de maintien axiaux comprennent au moins un ergot radial sur la face extérieure de la spire extérieure, l'ergot logeant au moins partiellement dans la rainure ;
• le ressort comprend plusieurs ergots radiaux répartis sur la face extérieure de la spire extérieure ;
• les ergots sont équidistants les uns des autres ;
• les ergots sont situés dans un plan transverse passant par le centre du ressort ;
• le ressort comprend sur la face interne de sa spire extérieure une bride glissante.

According to other advantageous variants of the invention:

• the axial holding means comprise at least one radial lug on the outer face of the outer turn, the lug housing at least partially in the groove;
• the spring comprises a plurality of radial lugs distributed on the outer face of the outer coil;
• the lugs are equidistant from each other;
• the lugs are located in a transverse plane passing through the center of the spring;
• the spring comprises on the inner face of its outer turn a sliding flange.

The invention also relates to a watch movement comprising at least one motor unit according to the invention.

Brief description of the drawings

• la figure 1 est une vue en perspective d'un ressort selon un premier mode de réalisation ne faisant pas partie de l'invention ;
• la figure 2 est une vue en coupe selon le plan médian vertical d'un organe selon un premier mode de réalisation ne faisant pas partie de l'invention ;
• la figure 3 est une vue en perspective d'un ressort conforme à l'invention selon un second mode de réalisation ;
• la figure 4 est une vue en coupe selon le plan médian vertical d'un organe moteur conforme à l'invention selon un second mode de réalisation.

Other features and advantages of the invention will appear more clearly on reading the following description of a particular embodiment of the invention, given as a simple illustrative and nonlimiting example, and the appended figures, among which: :

• the figure 1 is a perspective view of a spring according to a first embodiment not forming part of the invention;
• the figure 2 is a sectional view along the vertical median plane of a member according to a first embodiment not forming part of the invention;
• the figure 3 is a perspective view of a spring according to the invention according to a second embodiment;
• the figure 4 is a sectional view along the vertical median plane of a motor member according to the invention according to a second embodiment.

Detailed Description of the Preferred Embodiments

A motor unit according to the invention will now be described in the following with reference to Figures 1, 2 , 3 and 4 .

As illustrated in figures 2 and 4 , the motor unit 100 for a watch movement is provided with a barrel 1 comprising a bottom 10 integral with a drum 11. A spring 2 is wound inside the barrel 1, the inner coil 21 of the spring 2 being coupled to a bung 4 disposed around a shaft 5, and the outer coil 20 of the spring 2 being in contact with the circular wall of the drum 11.

According to the invention, the drum 11 comprises on its inner circular wall axial retention means of the spring 2, and the spring 2 comprises complementary holding means configured to cooperate with the axial holding means so as to maintain the spring 2 axially. within the barrel 1.

According to a first embodiment, not included in the invention, illustrated in FIGS. Figures 1 and 2 , the spring 2 has at its outer turn 20 a lowering so that the height h of the outer turn 20 is lower than the rest of the spring 2 which has a height H. The spring 2 can, for example, be lowered on a turn and 15 ° so that the outer turn 20 comes to be housed integrally in the shoulder 13 peripheral.

The drum 11 has a shoulder 13 on its inner circular wall, the shoulder 13 having a height substantially identical to the height h of the outer turn 20 so as to maintain axially the outer turn 20, and implicitly the spring 2.

The spring 2 can be equipped with a sliding flange 23 on the inner face of the outer turn 20, so as to hold the spring against the inner wall of the drum 11.

As can be seen at figure 2 , the motor member 100 has a barrel 1 without lid, a ratchet 3 being disposed above of the barrel 1 and drives the bung 4 disposed around the shaft 5. The outer turn 20 is disposed at the shoulder 13.

According to a second embodiment, illustrated in figure 3 and 4 , the spring 2 whose outer turn 20 has on its outer face a plurality of lugs 22 intended to cooperate with a peripheral groove 12 machined on the inner circular wall of the drum 11. Advantageously, the lugs 22 are arranged equidistant from each other on the outer face of the outer turn 20 to ensure a better axial retention of the spring 2.

The spring 2 can be equipped with a sliding flange 23 on the inner face of the outer turn 20, so as to hold the spring against the inner wall of the drum 11.

The spring 2 can be made in one piece and is in the form of a ribbon. The spring can thus be mounted on the bung 4 around the shaft of the barrel. The spring 2 may have a height of 1.30 mm, this height may be slightly greater than that of the barrel as shown in FIG. figure 2 .

The lugs 22 are located in a transverse plane passing through the center of the spring, and may have a diameter of between 0.4mm and 0.6m, and a depth of between 0.05mm and 0.1mm.

According to the invention, the drum 11 comprises on its inner circular wall a peripheral groove 12 configured to at least partially receive the lug 22 of the spring 2 so as to maintain the spring 2 axially within the barrel 1.

According to another embodiment of the invention, the inner circular wall of the drum 11 comprises a shoulder adapted to at least partially retain the lug 22 of the spring 2, the shoulder extending preferably from the bottom 10 of the barrel 1 until halfway up the inner circular wall of the drum 11.

As can be seen at figure 4 , the motor member 100 has a barrel 1 without a cover, a ratchet 3 being disposed above the barrel 1 and causes the plug 4 disposed around the shaft 5. Advantageously, in such an embodiment, the spring 2 can slightly exceed the barrel 1, thus limiting the size of the barrel 1.

The invention also relates to a watch movement and a timepiece equipped with a motor member 100 according to the invention.

Thanks to these different aspects of the invention, there is a compact motor member for maintaining the spring in the barrel and also to reduce the thickness of the watch movement.

Of course, the present invention is not limited to the illustrated example and is susceptible of various variations and modifications that will occur to those skilled in the art.

NOMENCLATURE

1.

barrel,

10.

Background,

11.

Drum,

12.

Groove,

13.

shoulder,

2.

Spring,

20.

Outdoor spire,

21.

Inner spire,

22.

ergot,

23.

Slippery flange,

3.

Ratchet,

4.

Crowded,

5.

Tree,

100.

Motor organ,

h.

Outside turn height,

H.

Spring height.

Claims (7)

1. Motor member (100) for a clock movement equipped with a barrel (1) comprising a drum (11), and at least one spring (2), the spring (2) being wound inside the barrel (1), the inner coil (21) of the spring (2) being coupled to a core (4), and the outer coil (20) of the spring (2) being in contact with the inner circular wall of the drum (11), the drum (11) comprising, on the inner circular wall thereof, axial means for retaining the spring (2) in the form of a peripheral groove, and the spring (2) comprising complementary retaining means configured to engage with the axial retaining means so as to axially maintain the spring (2) inside the barrel (1).
2. Motor member (100) for a clock movement according to claim 1, wherein the axial retaining means comprise at least one radial catch (22) on the outer face of the outer coil (20), the catch being housed at least partially inside the groove.
3. Motor member (100) for a clock movement according to either claim 1 or claim 2, wherein the spring (2) comprises a plurality of radial catches (22) distributed on the outer face of the outer coil (20).
4. Motor member (100) for a clock movement according to any of claims 1 to 3, wherein the catches (22) are equally spaced from one another.
5. Motor member (100) for a clock movement according to any of claims 1 to 4, wherein the catches (22) are located in a transverse plane passing through the centre of the spring (2).
6. Motor member (100) for a clock movement according to any of the preceding claims, wherein the spring (2) comprises a slipping bridle (23) on the inner face of the outer coil thereof.
7. Clock movement comprising at least one motor member (100) according to one of the preceding claims.

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