EP3859449A1 - Hairspring driving cord - Google Patents

Abstract

The present invention relates to a method for depositing (500) an electrically conductive layer electrically connecting at least one outer coil (105) and a peak (102) and representing at least 1%, in particular 5%, preferably 10% and / or at most 90%, in particular at most 75%, preferably at most 50% of at least one dimension of a watch balance spring (101).

Description

Technical area

The present invention relates to an oscillating system for a clockwork movement. The present invention relates in particular to an oscillating system comprising a clock hairspring from which electrostatic charges can be eliminated.

Technological background

It is known in the field of watchmaking the balance springs which constitute with the balance the time base of mechanical timepieces. These spirals are schematically in the form of a very fine spring wound in concentric turns and a first end of which is connected to a ferrule and a second end of which is connected to a stud.

The material used for making the balance springs is usually an alloy based on iron, cobalt, nickel and chromium. Ductile, such an alloy must resist corrosion. Recent developments suggest making the balance springs out of silicon. Due to their very small dimensions and the friction with the air and between the turns, the spirals tend to become charged with static electricity, so that the turns stick to each other. The balance springs are then unusable as they are.

Furthermore, the current methods aiming to discharge the electrostatic charges in the movement via the eyebolt involve an electrically conductive adhesive binding the eyebolt and balance spring. It is generally the mixture of a photo- or UV-curable adhesive and conductive particles. But these particles interfere with the crosslinking of the whole. This can lead to partial crosslinking and therefore piton-hairspring separation, which is detrimental to the operation of the oscillator. Another solution is to increase the crosslinking time significantly, but this goes against industrial production rates.

Finally, in certain cases, the electrostatic charges can be located elsewhere than on the hairspring but in the environment close to the latter, for example a component made of insulating material initially charged during assembly or charged during movement. These loads, generally linked to an element significantly more massive than the balance spring, will therefore attract the balance spring and lead to malfunctions by introducing stresses within it and therefore a modification of its natural frequency.

To overcome these problems, more or less complex solutions suggesting for example to carry out on all or part of the surface of the balance-springs a weak deposit of a material, preferably stainless and non-magnetic, such as gold, platinum. , rhodium or silicon have been proposed. However, such techniques require additional manufacturing steps which have the particular drawback of being expensive. In addition, these techniques tend to slow down production rates. To remedy these drawbacks, the present invention provides an oscillating system for a clockwork movement comprising a clockwork balance spring from which electrostatic charges can be eliminated.

Summary of the invention

• Fourniture dudit système oscillant ; et/ou
• Dépôt d'au moins une première couche électroconductrice reliant électriquement ladite au moins une spire extérieure et ledit piton et représentant au moins 1%, notamment 5%, de préférence 10% et/ou au plus 90%, notamment au plus 75%, de préférence au plus 50% d'au moins une dimension dudit spiral horloger.

To remedy these drawbacks, the present invention proposes a method for depositing an electrically conductive layer on an oscillating system of a watch movement comprising a watch balance spring with at least one turn fixed by a stud; said deposition process comprising a step of:

• Provision of said oscillating system; and or
• Deposit of at least a first electrically conductive layer electrically connecting said at least one outer turn and said peak and representing at least 1%, in particular 5%, preferably 10% and / or at most 90%, in particular at most 75%, preferably at most 50% of at least one dimension of said watch balance spring.

Thanks to this arrangement, an oscillating system for a clockwork movement comprising a clockwork balance spring from which electrostatic charges can be eliminated.

According to one embodiment, said watch hairspring comprises at least one inner coil fixed by a ferrule and at least one outer coil fixed by said eyebolt.

According to one embodiment, said at least one first electrically conductive layer is deposited on the outside of said peak.

Thanks to this arrangement, said at least one first electrically conductive layer can be easily deposited.

According to one embodiment, the deposition of said first electrically conductive layer is carried out by an atomizer.

According to one embodiment, said atomizer comprises said at least one first electroconductive layer in liquid form surrounded by a sheathing gas so as to be unidirectional.

According to one embodiment, said atomizer is unidirectional.

According to one embodiment, said first electrically conductive layer comprises a continuous electrically conductive layer and / or a plurality of discrete electrically conductive layers so as to form a continuous electrically conductive layer.

By virtue of one or the other of these preceding arrangements, it can be deposited a continuous electrically conductive layer and / or a plurality of discrete electrically conductive layers in a targeted or unidirectional manner.
According to one embodiment, said at least one dimension is the length of said watch hairspring.

Thanks to this arrangement, an oscillating system for a clockwork movement comprising a clockwork balance spring from which electrostatic charges can be eliminated.

Brief description of the figure

The invention will be described below in more detail with the aid of the appended drawing, given by way of non-limiting example, which represents a method of depositing (500) an electrically conductive layer on an oscillating system (100). of a watch movement.

Detailed description of the invention

The figure 1 illustrates a method of depositing 500 of an electrically conductive layer on an oscillating system 100 of a watch movement comprising a watch balance spring 101 with at least one inner coil fixed by a ferrule and at least one outer coil 105 fixed by a stud 102.

One of the steps of said deposition process 500 is the supply 510 of said oscillating system 100. This is followed by the deposition of at least one first electrically conductive layer 110 by an atomizer 900 electrically connecting said at least one outer coil 105 and said pin 102. . preferably, said first electrically conductive layer 110 includes a continuous electrically conductive layer 111 and / or a plurality of discrete electrically conductive layers 115 so as to form a continuous electrically conductive layer 111.

Said at least one first electrically conductive layer 110, more particularly, said continuous electrically conductive layer 111 is deposited and / or said plurality of discrete electrically conductive layers 115 are deposited on the outside of said peak 102, more exactly on the part of said peak 102 being on the outside. of said watch hairspring 101 because it is easier to reach than the part which faces the turns of said watch hairspring 101.

Said atomizer 900 is configured to deposit said at least one first electroconductive layer 110 in liquid form surrounded by a sheath gas 119 so as to be unidirectional and therefore deposit said first electroconductive layer 110 on said at least one dimension, preferably the length of said watch balance spring 101, and representing at least 1%, in particular 5%, preferably 10% and / or at most 90%, in particular at most 75%, preferably at most 50% of at least one dimension of said watch balance spring 101. Furthermore, said atomizer 900 being unidirectional, the deposition of said at least one first electroconductive layer 110 may only partially cover the width of said watch hairspring 101 but perhaps not the whole of the width of said watch hairspring 101 which makes it possible to avoid a change in characteristic of said watch balance spring 101 such as for example its inertia or its frequency, or a modification of its elastic response.

Thus, by virtue of this arrangement, the conduction of electric charges is made possible by the deposition of said at least one first electrically conductive layer 110 on its surface.

Moreover, the deposition process is economical by virtue of its simplicity, and the little material deposited. In addition, unlike a glue loaded with silver or carbon nanoparticles, for example, this deposition process does not expose employees to potentially dangerous particles during said preparation of these glues or during deposition due to their inhalation. because the spraying is rarely directional or even unidirectional. Another disadvantage to conventional spraying is that this can pollute nearby moving components such as the escapement or the balance axle and therefore disrupt their tribological functions.

Claims (7)

A method of depositing (500) an electrically conductive layer on an oscillating system (100) of a watch movement comprising a watch balance spring (101) with at least one turn (105) fixed by a stud (102); said deposition process (500) comprising a step of: - Supply (510) of said oscillating system (100); and or - Deposit of at least a first electrically conductive layer (110) electrically connecting said at least one outer turn (105) and said peak (102) and representing at least 1%, in particular 5%, preferably 10% and / or at most 90%, in particular at most 75%, preferably at most 50% of at least one dimension of said watch balance spring (101). A deposition method (500) according to claim 1, wherein said at least one first electrically conductive layer (110) is deposited on the exterior of said peak (102). A deposition method (500) according to claim 1 or 2, wherein the deposition of said first electroconductive layer (110) is performed by an atomizer (900). A deposition method (500) according to claim 3, wherein said atomizer (900) comprises said at least one first electrically conductive layer (110) in liquid form surrounded by a sheath gas (119) so as to be unidirectional. A deposition method (500) according to claim 4, wherein said atomizer (900) is unidirectional. A deposition method (500) according to any one of claims 3 to 5, wherein said first electrically conductive layer (110) comprises a continuous electrically conductive layer (111) and / or a plurality of discrete electrically conductive layers (115) so as to form a continuous electrically conductive layer (111). A deposition method (500) according to any preceding claim, wherein said at least one dimension is the length of said clock hairspring (101).

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