US3896614A

US3896614A - Balance-cock-and-regulator assembly for a timepiece movement

Info

Publication number: US3896614A
Application number: US471989A
Authority: US
Inventors: Peter Bachmann
Original assignee: Ebauches Bettlach SA
Current assignee: Ebauches Bettlach SA
Priority date: 1973-06-08
Filing date: 1974-05-21
Publication date: 1975-07-29
Anticipated expiration: 1992-07-29
Also published as: DE2426631A1; JPS5033860A; CH838173A4; CH577194B5; JPS584790B2

Abstract

A balance-cock-and-regulator assembly for a timepiece movement comprising a balance cock with an opening for a bearing, an additional opening peripherally spaced from the bearing opening for rotatably mounting a regulator which cooperates with a hairspring.

Description

United States Patent Bachmann BALANCE-COCK-AND-REGULATOR ASSEMBLY FOR A TIMEPIECE MOVEMENT Peter Bachmann, Bettlach, Switzerland Ebauches Bettlach S.A., Bettlach, Switzerland Filed: May 21, 1974 Appl. No.: 471,989

Inventor:

Assignee:

Foreign Application Priority Data June 8, 1973 Switzerland 8381/73 U.S. Cl. 58/109 Int. Cl. G04b 17/14 Field of Search 58/109, 114, I15

[ July 29, 1975 [56] References Cited UNITED STATES PATENTS 2,524,902 lO/l950 Fengler 58/109 Primary Examiner-George H. Miller, Jr. Attorney, Agent, or Firm-Stevens, Davis, Miller & Mosher ABSTRACT A balance-cock-and-regulatori assembly for a timepiece movement comprising a balance cock with an opening for a bearing, an additional opening peripherally spaced from the bearing opening for rotatably mounting a regulator which cooperates with a hairspring.

8 Claims, 2 Drawing Figures PATENTEUJULZQWB 3,896,614

SHEET 1 FIG. I

1 BALA NCE-COCK-AND-REGULATOR ASSEMBLY FOR A TIMEPIECE MOVEMENT This invention relates to a balance-cock-andregulator assembly for a timepiece movement intended to be incorporated in a watch movement, and more particularly in a wrist-watch movement of simplified construction. Consequently, it is sought to produce the assembly using as few parts as possible, and using parts which can be manufactured quickly and efficiently while affording the necessary precision for performing the functions which this assembly is called upon to perform.

Attempts have already been made to produce simplified regulator assemblies. Thus regulators are known which consist of a blanked sheet-metal part having a bent arm, two adjacent portions of which form the legs of a U and act as the regulator key and pin. The outermost turn of the hairspring is guided between the two legs of the U. Balance-cocks are also known which have a lateral element bent in a direction parallel to that of the axis of the balance and serving as a hooking member for the end of the last outer turn of the hairspring.

However, the regulators of timepiece movements, and particularly of watch movements, are generally mounted rotatingly about the frustoconical lateral face of the cock endstone. This latter part is a disc-shaped plate to which is fastened an element of the bearing which supports the end of the balance-staff. It is attached to the balance-cock by means of two screws.

In other designs, where the bearing which receives the end of the balance-staff is a shock-absorbing bearing, the bearing-block is mounted on a bearing housing, part of which is driven into an opening in the balancecock. This bearing housing may also be held in place by a bolt. It generally has at its periphery a frustoconical bearing surface which extends above the surface of the balance-cock, and it is about this frustoconical bearing surface that the regulator pivots.

Timepiece movements are likewise known where the regulator pivots about a generally circular projection formed by stamping and turning in the balance-cock. Finally, the regulator may also pivot about the body of a cup-bearing screwed into the balance-cock and supporting one of the ends of the balance-staff.

All of the aforementioned regulator assemblies comprise at least one element, generally the balance-cock or the bearing housing, which must undergo numerous machining operations during their manufacture, and their fitting very often necessitates the setting of one or more screws.

I Thus it would be desirable to be able to produce not only the regulator, but also the balance-cock, starting from flat metal plates shaped solely by blanking and bending operations. As a matter of fact, with an arrangement of this type, not only is the manufacture of the regulator and of the balance-cock greatly simplified, but what is more, the fitting of the assembly requires only a minimum of different operations.

The object of this invention is therefore to provide these advantages.

To this end, in the assembly according to the present invention. the hairspring stud, the regulator key and pin, and the means for pivoting the regulator consist of blanked and bent elements of the balance-cock and of the regulator.

A preferred embodiment of the invention will now be described in detail with reference to the accompanying drawings, in which:

FIG. 1 is a top plan view and FIG. 2 is a section taken on the line ll-Il of FIG. 1.

The drawing shows a portion of a watch movement of simplified construction. A base plate 1 carries a balance-cock 2 by means of two pillars integral with base plate 1. Balance-cock 2 is fastened on these pillars by screws 3. ln coaxial openings, balance-cock 2 and base plate I carry bearings 4, between which a balance-staff 5 pivots. Driven onto balance-staff S is a blanked disc 6 which constitutes the rim, the arms, and the hub of the balance and which also carries a roller-pin 7. Balance-staff 5 also bears a collet 8 to which the inner end of a hairspring 9 is fastened. Roller-pin 7 and a groove 10, milled parallel to the axis in a cylindrical collar of balance-staff 5, cooperate with a pallet 11, the body of which, blanked in a fiat metal plate, is driven onto an arbor 12 which pivots between balance-cock 2 and base plate 1.

The general shape of balance-cock 2 may be seen in FIG. 1. As has already been mentioned, it ensures the pivoting of the balance and of the pallet, the radius of rim 6 of the balance being less than the distance between the axes of the balance and the pallet. Balancecock 2 has a first tongue 13 which is bent downward slightly and which serves to support a sliding crownwheel (not shown). A second tongue 14 is provided with a notch 15 serving to hold a stem-cock (not shown) in place.

The bearing 4 which enables the upper end of balance-staff 5 to pivot is fastened in a circular opening 16 blanked in balance-cock 2. Around this opening extends an annular zone 17 limited for a little more than by an arcuate portion 18 of the edge of balancecock 2 and for another portion covering an angle of about 60 by a likewise arcuate inner edge 19 of an opening 32 blanked in balance-cock 2. This opening 32 is defined by two radial edges and an outer edge 28, also in the form of an arc of a circle having its center on bearing 4.

Arcuate edges

18 and 19 cooperate with elements of a regulator 20 so that the latter may pivot. Regulator 20 is a metal plate, preferably of steel, formed entirely by blanking, like balance-cock 2. It is generally circular in shape and has a lateral projection 21 which extends radially, and the end of which, as may be seen in FIG. 2, is bent in the shape of a U in such a way that the two vertical legs of this U extend one on each side of the outermost turn of hairspring 9. Regulator 20 also has a profiled central opening, the outline of which defines three V-shaped

inner tongues

22, 23 and 24, and between these three tongues, three straight-sided

radial tongues

25, 26 and 27. As may be seen in FIG. 2, V-

shaped tongues

22, 23, and 24 extend in the plane of regulator 20, whereas

tongues

25, 26, and 27 are bent downward at an angle of about 60. They are engaged under balance-cock 2 opposite

arcuate portions

18 and 19, while

tongues

22, 23, and 24 rest on annular zone 17. In order to ensure the engagement of regulator 20, the thickness of the metal plate in which it is blanked and the angle at which

tongues

25, 26, and 27 are bent are such that the radius vectors of the inner ridges of the edges of these tongues are shorter than the radius of the arcs of a

circle

18 and 19, while the radius vectors of the outer ridges of the edges of the tongues are longer than the radius of the arcs of a

circle

18 and 19. Thus when regulator 20 is laid horizontally on balance-cock 2, the inclines of

tongues

25, 26, and 27 rest against the edges of

arcuate portions

18 and 19, and these tongues are slightly resiliently deformed outwardly, so that the inner ridges of their edges engage on the edges of arcuate portions 18 and I9, and

flat tongues

22, 23, and 24 can be brought into contact with the upper face of balance-cock 2. By means of resilient deformation,

tongues

25, 26 and 27, which are blanked symmetrically and with the same dimensions, keep regulator 20 centered. FIG. 1 shows the ends of

tongues

25, 26, and 27 to be rounded. This shape facilitates the engagement of regulator 20 on balance-cock 2. The periphery of regulator 20 is circular, and its radius is very slightly less than that of the arcs of a circle which define the outside of opening 32, made in balance-cock 2 for the engagement of tongue 26. Tongue 21, the U-bent end of which forms the elements which act as the regulator key and pin, has a widened base, as may be seen in FIG. 1; and this base makes it possible to rotate regulator 20 about the axis of the balance. Thus with a simple blanked and bent plate, a part is obtained which exhibits all the necessary elements for performing the functions of the regulator. The distance between the two legs of the U formed by tongue 21 after bending will be adjusted so that hairspring 9 will have the desired amount of play between these two legs. As may be seen in FIG. 1, the portion of the last turn of hairspring 9 which is engaged between the two arms of tongue 21 is a circular portion, coaxial to the balance, which is limited on the inside by a double bend 29 formed in the last turn of hairspring 9. The end of this last turn is fastened to an element which acts as a hairspring stud. This element is also integral with balance-cock 2. It is blanked with balancecock 2 in the form of an L-shaped tongue 30. This tongue 30 is bent about halfway up the upright leg of the L, so that the lower part of this upright leg and the horizontal leg of the L extend in a plane parallel to the axis of the balance. This plane is moreover oriented substantially radially with respect to the axis of the balance. The horizontal leg of the L is provided with a notch 31, visible in FIG. 1, in which the end of the outermost turn of hairspring 9 is engaged. This end of hairspring 9 is fastened to tongue 30 by gluing or soldering. As shown in FIG. 1, it rests against the edge of the upright leg of L-shaped tongue 30, and it is to this part of tongue 30 that it is glued or soldered.

As a variation, the width of tongue 30 where it is bent vertically could be reduced with respect to its width at its base, and this arrangement would make it possible to reduce the size of bend 29 and to bring the last portion of the outermost turn of hairspring 9 closer to the other turns.

Another variation which may be mentioned is that the bottom of notch 31 could be oblique instead of comprising a vertical wall and a horizontal wall.

Thus a balance-cock-and-regulator assembly has been described which is of extremely simple construction since it is entirely formed starting from two plates, one of which constitutes the balance-cock and will be made of brass or nickel silver, for instance, while the other constitutes the regulator, preferably made of steel. These two flat plates are blanked and bent in accordance with carefully designed outlines. It then suffices to fasten upper bearing 4 of the balance in opening 16 of balance-cock 2 and to engage the three obliquely bent tongues of regulator 20 on

arcuate edges

18 and 19 of balance-cock 2 in order for regulator 20 to be fitted in place. At the time of assembly, the last turn of hairspring 9 will be engaged between the legs of the U formed by tongue 21, and the end of hairspring 9 will be engaged in notch 31 of tongue 30. It will be fastened to the edge of the upright leg of tongue 30 by gluing or soldering, for example.

Thanks to the three

tongues

25, 26, and 27, regulator 20 is kept centered, and it can rotate about its axis through an angle which corresponds to the angle of opening 32, in the form of a sector of an annulus, in balance-cock 2. This is an angle of about which corresponds to the practical requirements. As may be seen in FIG. 1, it is not absolutely indispensable for the three

tongues

25, 26, and 27 to be positioned at from one another and for the three

tongues

22, 23, and 24 to be identical. In the embodiment illustrated in the drawing, tongue 24 is shorter than

tongues

22 and 23, and

tongues

25 and 27 are closer to one another than

tongues

25 and 26 or 26 and 27. Nonetheless, the arrangement described ensures the positioning and guidance of regulator 20, and this guidance is precise enough for the displacement of tongue 21 to ensure a gradual correction of the frequency of the oscillating assembly. Thus by displacing regulator 20 about its axis, the rate of the watch can be timed with the best possible precision.

What is claimed is:

1. A balance-cock-and-regulator assembly for a timepiece movement, comprising: a balance cock having an opening for receiving a bearing secured into said opening and arcuate edge portions concentric to said opening, said edge portions having a radius greater than that of said bearing; and a regulator cooperating with a hairspring and having a profiled opening defining several tongues, some of said tongues engaging said edge portions on one side of said cock whereas the other tongues engage said edge portions on the other side of said cock, thus constituting pivoting means for said regulator on said balance cock.

2. An assembly according to claim 1, wherein the regulator comprises a substantially flat member having a finger bent in a U-shape, thus forming two legs extending on each side of the outermost turn of the hairspring.

3. An assembly according to claim 1, wherein said balance cock comprises an L-shaped tongue blanked in the balance cock and bent so that the upright leg of the L is perpendicular to the plane of the balance cock, said leg constituting a hairspring stud.

4. An assembly according to claim 3, wherein the balance-cock comprises a substantially flat plate having a tongue bent at right angles to its plane and forming the hairspring stud.

5. An assembly according to claim 4, wherein one of said arcuate edge portions forms part of the outline of the balance-cock, and wherein another arcuate edge portion forms the inner edge of an elongated opening blanked in the balance-cock and serving to engage at least one bent tongue.

6. An assembly according to claim 1, wherein the cock comprises a plane annular zone limited on the outside by said edge portions and on the inside by said opening.

7. An assembly according to claim 6, wherein the regulator comprises three flat V-shaped tongues resting 6 tors of the inner and outer ridges of the edges of the straight-sided tongues are shorter and longer, respectively, than the radius of the outer edges of said annular zone.

Claims

7. An assembly according to claim 6, wherein the regulator comprises three flat V-shaped tongues resting upon said annular zone, and between said V-shaped tongues, three straight-sided tongues bent obliquely downward and engaged under said annular zone.

8. An assembly according to claim 7, wherein the thickness of the regulator and the angle of bending of said straight-sided tongues are such that the radius vectors of the inner and outer ridges of the edges of the straight-sided tongues are shorter and longer, respectively, than the radius of the outer edges of said annular zone.