Optimized escapement

Patent metadata

Field	Value
Publication number	US-9292002-B2
Application number	US-201414560433-A
Country	US
Kind code	B2
Filing date	Dec 4, 2014
Priority date	Dec 23, 2013
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

A timepiece escapement mechanism includes a stopper between a resonator and an escape wheel set. The wheel set includes a magnetized track with an angular period of travel over which its magnetic characteristics are repeated. The stopper includes a magnetized or ferromagnetic pole shoe that is mobile in a transverse direction relative to the direction of travel of an element of a surface of the track. The pole shoe or the track creates a magnetic field in a pole gap between the pole shoe and the surface. The pole shoe is opposite a magnetic field barrier on the track just before each transverse motion of the stopper commanded by the periodic action of this resonator. The stopper is multistable and arranged to occupy at least two stable positions.

First claim

What is claimed is:

1. An escapement mechanism for a timepiece, comprising:
a stopper between a resonator and an escape wheel set,
wherein said escape wheel set includes at least one magnetized or ferromagnetic, or respectively, electrized or electrostatically conductive track with an angular period of travel over which the magnetic, or respectively, electrostatic characteristics thereof are repeated, said stopper including at least one magnetized or ferromagnetic, or respectively, electrized or electrostatically conductive pole shoe, said pole shoe being movable in a transverse direction relative to the direction of travel of at least one element of a surface of said track, and at least said pole shoe or said track creating a magnetic or electrostatic field in a pole gap between said at least one pole shoe and said at least one surface,
wherein said pole shoe is confronted with a magnetic or electrostatic field barrier on said track just before each transverse motion of said stopper actuated by the periodic action of said resonator,
wherein said stopper is multistable and arranged to occupy at least two stable positions, and
wherein said magnetic or electrostatic field, created by said pole shoe or said track, in a pole gap between said at least one pole shoe and said at least one surface, generates a torque or force which is applied to said at least one pole shoe and said at least one surface, and further wherein said torque or force is a periodic braking torque or force according to said angular period of travel, with, starting from a null value for said torque or force, a first half-period including a ramp of potential wherein said braking torque or force is substantially constant around a first value, and a second part of the period including a barrier of potential wherein said braking torque or force increases and reaches the maximum value thereof which is a second value at least three times said first value and of the same sign as said first value.

2. The escapement mechanism according to claim 1 , wherein each said track includes, before each said barrier, a ramp interacting in an increasing manner with a said pole shoe with a magnetic or respectively, electrostatic field whose intensity varies so as to produce increasing potential energy, said ramp taking energy from said escape wheel set and in that each said barrier of potential is steeper than each said ramp of potential.

3. The escapement mechanism according to claim 2 , wherein, between two said successive ramps of the same said track or two said neighbouring tracks in said direction of travel, said escape wheel set includes said magnetic, or respectively, electrostatic field barrier of potential, for triggering a momentary stop of escape wheel set prior to a tilting of said stopper under the periodic action of said oscillator.

4. The escapement mechanism according to claim 1 , wherein said torque or force is a periodic braking torque or force according to said angular period of travel, and in that, starting from a null value for said torque or force at the start of said period, said braking torque or force is of a positive intensity with an increasing value over a first angle until reaching a plateau and with a substantially constant first value over a second angle, the combination of said first angle and said second angle forming a ramp of potential, until a threshold is reached, after which the intensity then increases to a second maximum value higher than said first value over a third angle, at the end of said third angle corresponding to a peak at a maximum level of torque or force at said second value, after which the intensity of said torque or force falls over a fourth angle to reach a null value, which corresponds to a maximum energy level, and the combination of said third angle and said fourth angle constitutes a barrier of potential at which the braking torque or force is positive, then beyond which said braking torque or force continues to fall over a fifth angle until reaching a minimal negative intensity at a trough, before climbing once again, over a sixth angle to return to a positive value and start the next period, and wherein TD=T 1 +T 2 +T 3 +T 4 +T 5 +T 6 , and wherein T 1 +T 2 ≧TD/2.

5. The escapement mechanism according to claim 4 , wherein said barrier defines a discontinuity threshold by the sudden increase or reduction in said torque or force, over a travel corresponding to said third angle, and in that said third angle is less than a third of said second angle.

6. The escapement mechanism according to claim 1 , wherein said second maximum value is more than six times greater than said first value.

7. The escapement mechanism according to claim 1 , wherein said mechanism includes mechanical stopping means to prevent said stopper from changing to negative torque over a fifth angle or a sixth angle of said second half-period.

8. The escapement mechanism according to claim 1 , wherein said stopper is a pallet fork.

9. An escapement mechanism for a timepiece, comprising:
a stopper between a resonator and an escape wheel set,
wherein said escape wheel set includes at least one magnetized or ferromagnetic, or respectively, electrized or electrostatically conductive track with an angular period of travel over which the magnetic, or respectively, electrostatic characteristics thereof are repeated, said stopper including at least one magnetized or ferromagnetic, or respectively, electrized or electrostatically conductive pole shoe, said pole shoe being movable in a transverse direction relative to the direction of travel of at least one element of a surface of said track, and at least said pole shoe or said track creating a magnetic or electrostatic field in a pole gap between said at least one pole shoe and said at least one surface,
wherein said pole shoe is confronted with a magnetic or electrostatic field barrier on said track just before each transverse motion of said stopper actuated by the periodic action of said resonator,
wherein said stopper is multistable and arranged to occupy at least two stable positions,
wherein said escapement accumulates potential energy received from said wheel set during each half of said period, and returns energy to said resonator between said half-periods during said transverse motion of said stopper actuated by the periodic action of said resonator, wherein said pole shoe changes from a first relative transverse half-travel in relation to said escape wheel set to a second relative transverse half-travel in relation to said escape wheel set, or inversely, and
wherein at least said pole shoe or said track creates said magnetic or electrostatic field of a greater intensity in said first half-travel than in said second half-travel during a first half-period, and inversely during a second half-period.

10. An escapement mechanism for a timepiece, comprising:
a stopper between a resonator and an escape wheel set,
wherein said escape wheel set includes at least one magnetized or ferromagnetic, or respectively, electrized or electrostatically conductive track with an angular period of travel over which the magnetic, or respectively, electrostatic characteristics thereof are repeated, said stopper including at least one magnetized or ferromagnetic, or respectively, electrized or electrostatically conductive pole shoe, said pole shoe being movable in a transverse direction relative to the direction of travel of at least one element of a surface of said track, and at least said pole shoe or said track creating a magnetic or electrostatic field in a pole gap between said at least one pole shoe and said at least one surface,
wherein said pole shoe is confronted with a magnetic or electrostatic field barrier on said

Assignees

• Swatch Group Res & Dev Ltd

Inventors

• Di Domenico Gianni
• Favre Jerome

Classifications

• G04C5/005

  Magnetic or electromagnetic means · CPC title

• G04B17/06

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

• G04B15/14 Primary

  Component parts or constructional details, e.g. construction of the lever or the escape wheel {(assembly and manufacture of the spring G04B1/145; assembly and manufacture of components, e.g. pinions, spindles G04B13/02; lubrication of clockwork bearings G04B31/008; oils for clockwork bearings in general G04B31/08)} · CPC title

• G04B17/32

  Component parts or constructional details, e.g. collet, stud {, virole or piton} · CPC title

• G04C3/105 Primary

  pawl and ratchet wheel being magnetically coupled · CPC title