Classifications

• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B31/00—Bearings; Point suspensions or counter-point suspensions; Pivot bearings; Single parts therefor
  • G04B31/004—Bearings; Point suspensions or counter-point suspensions; Pivot bearings; Single parts therefor characterised by the material used
  • G04B31/016—Plastic bearings
• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B31/00—Bearings; Point suspensions or counter-point suspensions; Pivot bearings; Single parts therefor
  • G04B31/004—Bearings; Point suspensions or counter-point suspensions; Pivot bearings; Single parts therefor characterised by the material used
• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B31/00—Bearings; Point suspensions or counter-point suspensions; Pivot bearings; Single parts therefor
  • G04B31/004—Bearings; Point suspensions or counter-point suspensions; Pivot bearings; Single parts therefor characterised by the material used
  • G04B31/008—Jewel bearings
• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B31/00—Bearings; Point suspensions or counter-point suspensions; Pivot bearings; Single parts therefor
  • G04B31/004—Bearings; Point suspensions or counter-point suspensions; Pivot bearings; Single parts therefor characterised by the material used
  • G04B31/008—Jewel bearings
  • G04B31/0082—Jewel bearings with jewel hole and cap jewel
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49826—Assembling or joining

Definitions

• the present invention relates to the pivoting devices of a shaft in a timepiece, which comprises two pivots each forming one end of the shaft and two bearings for receiving the two pivots, each of the two pivots comprising, close to the end, a substantially cylindrical portion and a convex rounded portion extending the substantially cylindrical portion and decreasing towards the end, each of the two bearings having a pivot structure resiliently held in place, the pivotal structure comprising a substantially cylindrical passage traversed by the substantially cylindrical portion of one of the pivots and a bearing surface against which the end of said pivot is provided to come to rest.
• FIGs 13-51 and 13-52 on page 291 of the book "Theory of Watchmaking” shows a half of a rocking arm swing device corresponding to the above definition.
• the pivot shown which forms one of the ends of a balance shaft, has an appointie shape and ends with a cylindrical portion slightly rounded tip.
• the pivoting is provided by a hole stone and a counter-pivot which are held in a kitten so as to form a pivot structure.
• the hole of the hole stone is a substantially cylindrical passage that surrounds the cylindrical portion of the pivot so as to radially retain the balance shaft.
• the counter-pivot is a bearing surface against which the rounded tip of the pivot is provided to come to rest. The kitten is elastically fixed in place.
• the exemplary pivoting device shown in FIG. 5 of CH 324'263 also corresponds to the above definition.
• the pivot shown in Figure 5 ends with a cylindrical portion slightly rounded tip.
• the pivoting is ensured by a single stone pierced with a blind hole with cylindrical wall. This stone is mounted in a kitten and forms with it a pivoting structure.
• the cylindrical portion of the pivot is engaged in the cylindrical wall hole, and the rounded end of the pivot can thus bear against the bearing surface formed by the flat bottom of the blind hole.
• the pivot structure is resiliently fixed in place in a conical seat housing of a bearing body, itself attached to the plate.
• An object of the present invention is therefore to provide a pivoting device of a balance shaft in which the amplitude difference between the different positions of the watch is reduced to a minimum. It achieves this goal by providing a device according to claim 1.
• each pivot bears against the inclined inner wall of the trapezoidal profile portion (By the profile of an opening is meant the shape that the contour of this opening presents when the latter is seen in section along a plane which contains the axis of the opening or, which amounts to substantially the same, according to a plane which contains the axis of rotation of the balance).
• the end of a pivot can not penetrate to the bottom of the opening.
• the support of the pivot against the bearing surface is never frontal.
• the diameter of the portion of the rounded portion whose flanks bear against the flared edge of an opening is preferably between about 0.05 and 0.10 mm.
• the wall of the inverted trapezoidal or triangular profile portion preferably has an inclination relative to the axis of the balance between about 40 ° and 60 °.
• the pivoting structure of each of the two bearings comprises an axial abutment element (15, 15 ') in which is arranged said opening (16, 16') of circular or polygonal section, and a radial guide member (21, 21 ') traversed by the substantially cylindrical passage.
• This first embodiment is similar to the pivoting of the prior art combining stones with holes and against pivots.
• the axial abutment element according to the invention differs from known counter-pivots, in particular in that it comprises an opening for receiving the rounded convex portion of a pivot. - AT -
• each of the abutment elements in which the opening is formed is constituted by a monocrystal, the opening itself being produced by wet anisotropic etching of the single crystal.
• the substantially cylindrical passage of the pivoting structure is constituted by a cylindrical wall portion of the opening of circular or polygonal section, the cylindrical wall portion being located between the profile portion. trapezoidal or triangular inverted and a mouth of the opening.
• This second embodiment is called monoblock because the substantially cylindrical passage and the bearing surface are made in the same opening of the pivot structure.
• This embodiment of the present invention somewhat recalls the pivoting device described in patent document CH 324 263 and already mentioned. However, it differs from this prior art in that the bottom of the opening is not flat but has an inclined wall.
• FIG. 1 is a schematic sectional view showing a pivot inserted into a radial guide member and an axial abutment member according to the present invention
• FIG. 2 is a partial sectional view schematically showing a pivoting structure of a pivoting device according to a first embodiment of the present invention
• - Figure 3 is a schematic sectional view showing the same elements as Figure 3, but in which the axis of the balance shaft is inclined relative to the vertical;
• FIG. 4 is a partial sectional view schematically showing a pivoting structure of a pivoting device according to a second embodiment of the present invention.
• FIG. 5 is a perspective view of an axial bearing element according to the invention, which can be obtained from a silicon wafer;
• FIG. 6 is a sectional view of the silicon wafer from which the axial bearing member of Figure 7 can be obtained.
• FIG 3 schematically shows a balance shaft 1 1 with its pivoting device.
• the ends of the shaft 1 1 form two pivots with rounded tip (referenced respectively 12 and 12 '). It can also be seen that the balance shaft 1 1 is held radially by two radial guide elements (21, 21 ') and axially by two axial abutment elements 15, 15' against which the pivots 12, 12 'can rest. .
• Figure 1 shows a half of the same pivot device vertically oriented.
• FIGS. 1 and 3 show that, in the example shown, the tip of the pivot 12 terminates in a rounded portion 13 forming substantially a half-sphere.
• the diameter of the sphere may advantageously be between 0.05 and 0.10 mm, for example about 0.07 mm.
• the end 13 of the pivot 12 is provided to abut against the inner wall 17 of a trapezoidal profile opening (referenced 16 in Figure 1) formed in an axial abutment member 15. It is seen that the opening 16 has the shape of a cone substantially coaxial with the axis of the balance shaft 1 1.
• the opening of the cone 16 is preferably between about 80 ° and 120 ° or, in other words, the inclination the wall 17 relative to the axis of the balance 1 1 is preferably between 40 ° and 60 °.
• FIGS. 1 and 3 show again that the rounded portion 13 and the opening 16 are dimensioned so that the lateral surface of the rounded portion 13 is entirely supported by the inclined wall 17.
• two arrows represent the direction perpendicular to the contact surface between the pivot 12 and the axial abutment element 15.
• the two arrows N have their origin at the location of a point-of-contact. It should be noted that the surfaces in contact are not uneven, which allows a "normal" support. In other words, at a point of support of the pivot 12 on the wall of the opening 16, the direction of the arrow N corresponds both to the direction normal to the surface of the pivot and in the normal direction to the inclined wall of the opening.
• the pivot 12 does not bear against the bottom of the opening 16, but against its inclined inner wall.
• the axis of the opening 16 being substantially parallel to the axis of the pivot 12, the contact of the pivot 12 with the interior of the opening 16 is by the flanks of the pivot, in an area of the surface of the latter whose inclination is the same as that of the walls of the cone; that is, about 50 ° in the present example.
• Figures 1 and 3 it can be seen that it is approximately the same area of the surface of the pivot that ensures contact when the balance shaft is horizontal and when the shaft is inclined.
• Figures 1 and 3 show that the pivots 12, 12 'comprise an elongated cylindrical portion 19, 19' which precedes the rounded end 13, 13 '.
• the elongate cylindrical portion passes into the olive or cylindrical hole of a radial guide member 21, 21 '.
• the function of the radial guide element corresponds to the function of a hole stone in a usual pivoting device.
• the radial guide element 21, 21 ' prevents the rounded end 13, 13' of the pivot from being completely released from the opening 16, 16 '. Indeed, with particular reference to Figure 3, we see that there is some clearance, both radial and axial, between the balance shaft 1 1 and the axial abutment members 15 and 15 '.
• This elastic suspension of the pivot structure is, in a manner known per se, provided to prevent the cylindrical portion 19 from breaking in the event of impact.
• the balance shaft 1 1 still has a tigeron (referenced 23 in Figure 1) substantially thicker than the cylindrical portion 19. Because of its dimensions, the tigeron 23 is much stronger than the end of a pivot 12, 12 ', and is provided to abut against a not shown portion of the device so as to absorb most of the energy associated with impact.
• FIG. 2 is a partial sectional view schematically showing a pivoting structure of a pivoting device according to a first embodiment of the present invention (the elements of Figure 2 also shown in Figures 1 and 3 retain the same reference numbers). It can be seen in the figure that the two stones respectively constituting the axial abutment element 15 and the radial guide element 21 are both mounted in a kitten (shown schematically) with which they form the pivot structure 25.
• the realization of the pivot structure 25 may present some difficulties. Indeed, it is easy to understand that it is important that the axis of the opening 16 and that of the substantially cylindrical passage of the radial guide element 21 are perfectly aligned. Indeed, as the diameter of the pivot is of the order of 0.1 mm., An offset of less than one hundredth of a millimeter between the axes of the two openings is sufficient to substantially affect the quality of pivoting.
• the axial abutment element 15 is housed in a cylindrical cavity 27.
• the diameter of the cavity 27 is slightly greater than that of the axial abutment element. The latter therefore enjoys some lateral play.
• the balance shaft is in a vertical position, as shown in FIG. 2, the rounded portion 13 of the point of the pivot bears against the inclined side of the opening 16 of the element 15. If, for a reason or a other, the opening 16 is not quite in the axis of the balance, the support of the tip of the pivot on the inclined edge is only one side of the opening.
• the thrust of the pivot on the edge of the opening is exerted asymmetrically, and the horizontal component of this thrust is sufficient to bring the axial abutment member 15 in the axis of the balance shaft . It will thus be understood that, the inclined wall of the opening 16 allows self-centering of the axial abutment element 15.
• the axial abutment element may be rigidly fixed in the pivot structure.
• the solution just described to the problems of alignment can be adapted to this case. Indeed, it is possible to precisely adjust the centering of the axial abutment element 15 at the assembly stage of the Pivot structure 25. To do this, a "false axis" is first inserted into the pivot structure 25 in the place provided for the balance shaft. The thrust of this "false axis" makes it possible to center the axial abutment element 15 according to a principle identical to that explained in the preceding paragraph.
• FIG 4 is a partial sectional view schematically showing a pivotal structure of a pivoting device according to a second embodiment of the present invention.
• the half device shown comprises a pivot 32 similar to the pivot 12 of Figures 1, 2 and 3. It has a tip having an elongate cylindrical portion 39 and ending with a rounded portion 33.
• the tip of the pivot 32 is inserted into an opening 36 of a pivot structure 35. It can be seen in the figure that the profile of the opening 36 has a first portion with a cylindrical wall 37 followed by a trapezoidal profile portion 38.
• the rounded tip 33 of the pivot is dimensioned so as to its rounded surface can bear against the inclined wall of the trapezoidal profile portion 38.
• a one-piece pivoting structure 35 fulfills both the functions of axial abutment element and radial guide element for the pivot 32.
• the embodiment of Figure 4 combines the elements 15 and 21 in a single piece.
• the monoblock element 35 is suitable for being made by example in a metal or an alloy or, still, plastic.
• the openings 16, 16 'and 36 are not necessarily circular in section. Indeed, as will be seen in the example which is shown in Figures 5 and 6 and which will now be described, the section of an opening may also be of polygonal section (by section of an opening, we mean the shape that presents the contour of this opening when the latter is seen in section transverse to the axis of the opening or, which is substantially the same, transversely to the axis of rotation of the balance).
• the axial abutment elements shown in FIGS. 1 to 3 may be made from a wafer of monocrystalline material such as silicon, for example.
• the known method of anisotropic etching in a liquid medium (or wet) is an advantageous way of digging polygonal openings of triangular or trapezoidal profile in monocrystalline wafers. Engraving or, more precisely, etching of a monocrystal is said to be anisotropic if the etch rate is higher in some crystallographic directions than in others.
• the anisotropy of chemical attack depends on many parameters. Firstly, it depends on the interaction between the chemical properties of the substance of which the single crystal is made and those of the attack reagent used.
• etch rates in the various crystallographic directions depend, of course, on the symmetry of the crystal structure.
• concentration of the reagent, the temperature, etc. it is therefore possible to make polygonal openings of relatively complex profile in a single crystal.
• a known example of wet anisotropic etching relates to silicon. Indeed, it is possible to form openings in the form of inverted pyramids in a silicon wafer of ⁇ 100> orientation by wet etching.
• Patent document US 2004/0195209 which is incorporated herein by reference, discloses one of a number of methods that can be implemented to provide such inverted pyramid shaped openings.
• Fig. 5 shows the axial abutment member 15 of a bearing for a pivoting device made from a monocrystalline silicon wafer 40 of ⁇ 100> orientation.
• the wafer is shown covered by a mask 43.
• This mask must be formed on the surface of the wafer before etching, so as to protect the silicon from the etching reagent.
• the mask has an opening 45 formed at the location where the opening 46 is to be etched in the silicon.
• the etching reagent digs a pyramid-shaped opening.
• the inclined faces of the pyramid may be either ⁇ 1 10> planes or ⁇ 1 1 1> planes. Whether the faces of the pyramid are ⁇ 1 10> planes or ⁇ 1 1 1> planes, the formed pyramid is of square section. Indeed, the directions ⁇ 1 1 1> and ⁇ 1 10> both have a rotation symmetry of order 4.
• the inverted pyramid constituting the opening 46 is slightly truncated (FIG. 6).
• the inclination of the planes ⁇ 1 10> is about 45 °, that of the planes ⁇ 1 1 1> of about 55 °.
• the edges of the trapezoidal portion of an opening has an inclination of between 40 ° and 60 °. Wet anisotropic etching is therefore particularly well suited to the present invention.
• the present invention is not limited to a pivoting device for a balance shaft.
• the pivoting device of the present invention may be used for any axis or shaft of the timepiece and, in particular, for the pivoting of the escapement or the anchor.
• the pivoting device according to the present invention may be made from other materials than traditional materials or silicon. Indeed, the invention can be made from any material that the skilled person deems fit to use.
• openings by wet anisotropic etching in monocrystals of galium arsenide or indium phosphide. It is useful to specify that these openings are distinguished from those described in the previous example in that they may have the form of inverted tetrahedrons (of triangular section) instead of inverted pyramids.
• the section of the openings may be circular or polygonal, and if the section is polygonal, the number of sides of the polygon may be arbitrary.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Pivots And Pivotal Connections (AREA)
• Holders For Apparel And Elements Relating To Apparel (AREA)
• Automotive Seat Belt Assembly (AREA)
• Rotary Switch, Piano Key Switch, And Lever Switch (AREA)
• Transmitters (AREA)
• Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
• Hinges (AREA)
• Support Of The Bearing (AREA)
• Sliding-Contact Bearings (AREA)

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Cited By (4)

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• 2007
  • 2007-04-26 EP EP07106986A patent/EP1986059A1/de not_active Withdrawn
• 2008
  • 2008-04-24 DE DE602008003429T patent/DE602008003429D1/de active Active
  • 2008-04-24 US US12/596,947 patent/US8317391B2/en active Active
  • 2008-04-24 WO PCT/EP2008/055009 patent/WO2008132135A2/fr not_active Ceased
  • 2008-04-24 EP EP08736544.1A patent/EP2142965B2/de active Active
  • 2008-04-24 JP JP2010504690A patent/JP5524827B2/ja active Active
  • 2008-04-24 AT AT08736544T patent/ATE487965T1/de not_active IP Right Cessation
  • 2008-04-24 CN CN2008800136752A patent/CN101669075B/zh active Active

Non-Patent Citations (1)

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