Rotary wheel set system of a horological movement

Patent metadata

Field	Value
Publication number	US-12259689-B2
Application number	US-202117338126-A
Country	US
Kind code	B2
Filing date	Jun 3, 2021
Priority date	Jun 26, 2020
Publication date	Mar 25, 2025
Grant date	Mar 25, 2025

Abstract

A rotary wheel set system of a horological movement with a rotary wheel set a first and a second bearing for a first and a second pivot of the arbor of the rotary wheel set, the wheel set including a mass center in a position of its arbor, the first bearing including an endstone including a main body equipped with a conical cavity configured to receive the first pivot of the arbor of the rotary wheel set, the first pivot being capable of cooperating with the cavity of the endstone to rotate in the cavity, at least one contact zone between the first pivot and the cavity being generated, the normals of the contact zone forming a minimum contact angle relating to the plane perpendicular to the arbor of the pivot, the minimum contact angle being less than or equal to 30°, preferably less than or equal to arctan (½).

First claim

The invention claimed is:

1. A rotary wheel set system of a horological movement, the system comprising:
a rotary wheel set; and
a first and a second bearing, for a first and a second pivot of the arbor of the rotary wheel set,
wherein the wheel set includes a mass center (G) in a position of its arbor,
wherein the first bearing includes an endstone comprising a main body equipped with a conical cavity configured to receive the first pivot of the arbor of the rotary wheel set,
wherein the first pivot being capable of cooperating with the cavity of the endstone in order to be able to rotate in the cavity, at least one contact zone between the first pivot and the cavity being generated, and
wherein normals of the contact zone form a minimum contact angle (α h ) relating to a plane perpendicular to the arbor of the first and second pivots, wherein the minimum contact angle (α h ) is less than or equal to 30°.

2. The wheel set system according to claim 1 , wherein the second bearing cooperates with the second pivot to enable the rotary wheel set to rotate about its arbor, the second bearing comprising a second cavity, the second pivot being capable of cooperating with the second cavity of the endstone in order to be able to rotate in the second cavity, at least one second contact zone between the second pivot and the second cavity being generated, the normals of the second contact zone forming a second minimum contact angle (α b ) in relation to the plane perpendicular to the arbor of the second pivot, wherein the minimum contact angles (α h ,α b ) of the two pivots and of the two bearings are defined by the following equation: cot α h +cot α b ≥2.5.

3. The wheel set system according to claim 1 , wherein the second minimum contact angle (α b ) is greater than or equal to arctan (½).

4. The wheel set system according to claim 1 , wherein the minimum contact angles (α h , α b ) are defined by the following equations:

tan
⁢
α

b

=

BH
_

4
⁢

GH
_

tan
⁢
α

h

=

BH
_

4
⁢

GB
_

R
h

R
b

=

μ
b

μ
h

⁢

GH
_

GB
_

where BH is the distance between the ends of the two pivots, GH is the distance between the end of the first pivot in contact with the first bearing and the mass centre (G) of the balance, and GB is the distance between the end of the second pivot in contact with the second bearing and the mass centre (G) of the balance 2 .

5. The wheel set system according to claim 1 , wherein the minimum contact angles α b , α h ) are defined by the following equations:
if GB<GH:

tan
⁢
α

b

=

1

2
⁢

GH
_

BH
_

⁢

(

1
+

2
⁢

GH
_

BH
_

)

⁢

(

1
+

2
⁢

GB
_

BH
_

)

tan
⁢
α

h

=

1

(

1
+

2
⁢

GH
_

BH
_

)

⁢

(

1
+

2
⁢

GB
_

BH
_

Assignees

• Eta Sa Mft Horlogere Suisse

Inventors

• Helfer Jean-Luc
• Lechot Dominique

Classifications

• G04B1/16

  Barrels; Arbors; Barrel axles (arrangements facilitating the removal of the mainspring G04B33/14) · CPC title

• G04B31/04 Primary

  with jewel hole and cap jewel {(jewel bearings with jewel hole and cap jewel G04B31/0082; tools for inserting jewel bearings G04D3/042)} · CPC title

• G04B33/00

  Calibers {(disposition of components of the automatic winding mechanism in relation to the clockwork G04B5/18)} · CPC title

• G04B17/06

  Oscillators with hairsprings, e.g. balance {(electrically driven balances G04C3/04; contacts actuated by a balance G04C13/065)} · CPC title

• G04B37/04

  Mounting the clockwork in the case; Shock absorbing mountings · CPC title