Balance spring stud-holder

An assembly for holding or supporting a timepiece balance spring including a base provided with an upper surface and a lower surface on which a balance spring stud and a stud-holder are arranged. The stud-holder secures the stud to an escapement mechanism.

This application claims priority from European Patent application No. 14199755.1 filed Dec. 22, 2014, the entire disclosure of which is hereby incorporated herein by reference.

The present invention concerns an assembly for holding or supporting a timepiece balance spring including a balance spring stud and a stud-holder, wherein said stud-holder includes:a base comprising a first stop member extending along a longitudinal axis of said base;means of securing said stud-holder to an escapement mechanism.

PRIOR ART

In a mechanical watch, it is usual to use a regulating member comprising a sprung-balance device. Conventionally, the inner end of the balance spring is attached to a collet provided on the balance staff. In order to attach and position the inner end of the balance spring, it is known to use a stud-holder housing a balance spring stud, in association with a clamping screw to clamp the stud against the portion of the balance spring engaged in the stud-holder.

In such an assembly, the stud-holder is conventionally attached to a balance-cock also used for attaching one of the ends of the balance staff. In practice, during assembly and/or timing, the operations to be performed with these various elements are difficult, since access is restricted and the parts are of very small dimensions. Moreover, with such configurations, it is common for the balance spring clamping screw or the balance spring stud-holder to come loose, and/or be lost during an operation such as adjustment of the active length of the balance spring.

SUMMARY OF THE INVENTION

It is an object of the invention to overcome the drawbacks of the prior art by proposing to provide an assembly for holding or supporting a timepiece balance spring which allows simplified assembly or disassembly of the balance spring stud.

To this end, the invention concerns an assembly for holding or supporting a timepiece balance spring including a base provided with an upper surface and a lower surface on which a balance spring stud and a stud-holder are arranged, wherein the stud-holder includes:means for securing said stud to an escapement mechanism, characterized in that the means for securing said stud include an orifice traversing said base and provided with a peripheral rim to form a housing for insertion of the stud, said means for securing said stud also including attachment means for rotatable attachment of a rotating element inside the housing, said rotating element having an outer edge cooperating with the stud to lock it between the outer edge thereof and the peripheral rim of the housing when the rotating element is assembled in the housing.

In a first advantageous embodiment, the peripheral rim is provided with a through notch in order to place the stud therein.

In a second advantageous embodiment, said rotating element is provided with a through notch in order to place the stud therein.

In a third advantageous embodiment, said rotating element is a hub.

In a fourth advantageous embodiment, said rotating element is a ring.

In a fifth advantageous embodiment, the hub includes a shock absorber system.

The invention also concerns an assembly for holding or supporting a timepiece balance spring including a base provided with an upper surface and a lower surface on which a balance spring stud and a stud-holder are arranged, wherein said stud-holder includes:means for securing said stud to an escapement mechanism, characterized in that the means for securing said stud include a blind circular hollow formed by a bottom and a peripheral rim, arranged on the upper surface of the base forming a housing for insertion of the stud, said means for securing said stud also including attachment means for rotatable attachment of a rotating element inside the housing, said rotating element having an outer edge cooperating with the stud to lock it between the outer edge of the rotating element and the peripheral rim of the housing when the rotating element is assembled in the housing.

In a first advantageous embodiment, said rotating element is a hub.

In a second advantageous embodiment, said rotating element is a ring.

In a third advantageous embodiment, the peripheral rim is provided with a through notch in order to place the stud therein.

In a fourth advantageous embodiment, said rotating element is provided with a through notch cooperating with a hole located in the bottom of the housing in order to place the stud therein.

In a fifth advantageous embodiment, the housing is a circular hollow, formed of a peripheral rim, an inner rim and a bottom, in which the rotating element is inserted, the inner rim defining a central portion protruding from the bottom.

In another advantageous embodiment, the inner rim is provided with a through notch cooperating with a hole located in the bottom of the housing in order to place the stud therein.

In another advantageous embodiment, the bottom of the housing includes a shock absorber system.

The invention also concerns an assembly for holding or supporting a timepiece balance spring, comprising a base provided with an upper surface and a lower surface on which a stud and a stud-holder are arranged, wherein the stud-holder includes:means for securing said stud to an escapement mechanism, characterized in that the means for securing said stud include a blind circular hollow formed by a bottom and a peripheral rim, arranged on the upper surface of the base forming a housing for insertion of the stud, said means for securing said stud also including attachment means for rotatable attachment of a rotating element inside the housing, said rotating element having an outer edge cooperating with the stud to lock it between the outer edge of the rotating element and the peripheral rim of the housing when the rotating element is assembled in the housing.

In a first advantageous embodiment, said rotating element is a hub.

In a second advantageous embodiment, said rotating element is a ring.

In a third advantageous embodiment, the peripheral rim is provided with a notch in order to place the stud therein.

In a fourth advantageous embodiment, said rotating element is provided with a through notch in order to place the stud therein.

In a fifth advantageous embodiment, the housing is a circular hollow formed of a peripheral rim, an inner rim and a bottom, in which the rotating element is inserted, the inner rim defining a central portion protruding from the bottom.

In a sixth advantageous embodiment, the inner rim is provided with a notch cooperating in order to place the stud therein.

In another advantageous embodiment, the hub includes a shock absorber system.

In another advantageous embodiment, the bottom of the housing includes a shock absorber system, the balance staff passing through the ring acting as rotating element.

In another advantageous embodiment, the central portion includes a shock absorber system.

In another advantageous embodiment, the peripheral rim includes at least one cavity comprising a countersink perpendicular to the plane of the base and open relative to the upper surface, and secant with said countersink and opposite the upper surface, a blind slot used to lock a rotating element in a bayonet fitting, said rotating element including at least one protruding portion cooperating with at least one aforementioned cavity.

In another advantageous embodiment, the peripheral rim and the rotating element each include a screw pitch enabling them to cooperate with each other.

DETAILED DESCRIPTION

The present invention proceeds from the general inventive idea of providing an assembly for holding or supporting a timepiece balance spring allowing the stud to be more easily assembled/disassembled and allowing the stud to be placed very close to the balance staff in order to use balance springs with a small external diameter.

FIG. 1shows a schematic view of an assembly1for holding or supporting a timepiece balance spring according to a first embodiment. This holding assembly1includes a stud-holder3arranged to be attached to the balance-cock5by attachment means7. The holding assembly also includes a balance spring stud9attached to one coil of the balance spring11. Stud-holder3uses securing means6to secure stud9to cock5.

In a first embodiment, cock5, also called the base, is provided with a housing50. This housing50takes the form here of a through opening or orifice51in which stud-holder3is placed, said stud-holder3being maintained in its housing50via attachment means7, as seen inFIGS. 1 and 2. Opening51has a peripheral rim51aand is of circular shape. The stud-holder includes a rotating element used for securing the stud to the cock. Attachment means7include a male interface71arranged on outer edge33of the rotating element and a female interface72arranged on peripheral rim51a. These male and females interfaces71,72thus cooperate together to allow the rotating element to be mounted in housing51via a rotational motion of said rotating element relative to cock5. This assembly via a rotational motion is used to lock the stud in housing50. Assembly via a rotational motion causes the stud to press on the peripheral rim. The rotating element, the housing and the attachment means form securing means6. To achieve this, two solutions are envisaged.

In a preferred mode of this first embodiment seen inFIGS. 5, 6 and 7, the rotating element takes here the form of a central hub30, which includes an upper face31, a lower face32and an outer edge33. This central hub30is of similar shape to that of the opening, i.e. circular.

In a first solution seen inFIGS. 1 and 3, the peripheral rim51ais provided with a through notch52whose dimensions are similar to those of stud9so that the latter can be placed therein. During assembly, stud9is initially placed in notch52of peripheral rim51a. Then, hub30is fixed in its housing51, by engaging male interface71of hub30with female interface72of peripheral rim51a. Hub30is then secured by rotation, which causes a contact between its outer edge33and stud9. The stud is thus pressed onto peripheral rim51aand locked. This solution allows the stud to be placed in a fixed position.

In a variant of this first solution seen inFIG. 1, hub30has an irregular shape so that the outer edge33in contact with stud9is not perfectly circular. Thus, outer edge33in contact with stud9includes a substantially triangular set back portion and forms a gentle slope. When hub30is rotated and secured in housing50, this configuration makes it possible to even out the increase in stress applied to stud9in order to lock it.

In a second solution seen inFIG. 4, hub30is provided with a through notch35whose dimensions are similar to those of stud9so that the latter can be placed therein. During assembly, stud9is initially placed in notch35of hub30. Then, hub30is secured inside its housing51by engaging male interface71of hub30with female interface72of peripheral rim51a. Hub30is then secured by rotation which causes a contact between peripheral rim51aand stud9. The stud is thus pressed onto peripheral rim51aand locked. This solution makes it possible to obtain a stud9whose position is angularly adjustable about the balance staff and thus allows adjustment of the position of the stud9.

In a variant of this second solution, as seen inFIG. 4, peripheral rim51ahas an irregular shape so that it is not perfectly circular. Thus, peripheral rim51aincludes a substantially triangular set back portion and forms a gentle slope. When the rotating element, i.e. hub30, is rotated and secured in housing50, this configuration makes it possible to even out the increase in stress applied to the stud in order to lock it.

In another preferred mode, the rotating element takes the form here of a ring300. This ring300includes an upper face301, a lower face302, an outer edge303and an inner edge304.

Rotating element3is advantageously used as a multi-functional hub. Thus, central hub30is arranged to include a shock absorber system100, as seen inFIGS. 1, 5, 6 and 7. The central hub thus includes a through or blind recess101, which houses shock absorber system100. A through recess101allows said shock absorber system100to be visible and thus improves aesthetics.

In the case of a ring300as seen inFIG. 8, the central orifice may be used to place a shock absorber system100therein.

Shock absorber system100may take a conventional form, that is to say a setting in which a jewel hole and an endstone are arranged, or the form of a single jewel. This single jewel is provided with a recess for cooperating with the balance staff and may be pressed into the hub hole or mounted via an elastic ring. Shock absorber system100could also take the form of a disc provided with elastic arms. One advantage of this configuration is that it provides a centered system, since the position of the stud is centred relative to the balance staff cooperating with the shock absorber system. Further, this provides an easy-to-assemble, multifunctional system acting as stud-holder3and shock absorber100. Shock absorber system100may be pre-mounted on the hub prior to final assembly with stud9.

Of course, shock absorber system100might not incorporated in hub30, but arranged on cock5in an off-centre position relative to central hub30. This configuration allows the use of a sprung balance assembly of large diameter without necessarily having a large hub30.

In a second embodiment visible inFIG. 9, cock5includes a housing500. This housing500takes the form here of a circular hollow510formed of a peripheral rim511, an inner rim512and a bottom513. Inner rim512forms a central island or central circular portion514protruding from bottom513of housing500. Rotating element3takes the form here of a ring300. This ring comprises an upper face301, a lower face302, an outer edge303and an inner edge304. Rotating ring300will be placed in said circular hollow510.

In this embodiment, attachment means7comprise a male interface701arranged on an edge of ring300and a female interface702arranged on one of the rims of housing500. Male interface701could be arranged on outer edge303of ring300, whereas female interface702will be arranged on peripheral rim511of housing500. However, male interface701could be arranged on inner edge304of ring300, whereas female interface702will be arranged on inner rim512of housing500.

These male and females interfaces701,702thus cooperate together to allow ring300to be mounted via a rotational motion relative to housing500. This assembly via a rotational motion is used to lock stud9in housing500. Assembly via a rotational motion causes the stud to press on a rim of the housing.

In a third embodiment visible inFIG. 10, cock5includes housing500. Housing500takes the form here of a circular hollow520formed of a peripheral rim521and a bottom522. The rotating element may take the form here of a hub30as described in the first embodiment, or a ring300as described in the first embodiment.

In this third embodiment, attachment means7include a male interface701arranged on outer edge303of the rotating element and a female interface702arranged on peripheral rim521. These male and females interfaces701,702thus cooperate together to allow the rotating element to be mounted in housing500via a rotational motion of said rotating element relative to cock5. This assembly via a rotational motion is used to lock stud9in housing500. Assembly via a rotational motion causes stud9to press on the peripheral rim.

In the second and third embodiment, a notch for housing the stud is provided.

According to a first solution seen inFIGS. 11 to 13, stud9is mounted in a non-adjustable fixed position on the stud-holder. Thus, a through notch515,523is arranged on peripheral rim511,521or on inner rim512. Stud9is then initially placed in notch515,523, and then the rotating element is fixed in its housing510,520by engaging male interface701with female interface702. Rotating element3is then rotated which causes a contact between one of the edges of the rotating element and stud9. The stud is thus pressed into notch515,523and locked. This solution allows the stud to be placed in a fixed position.

In a variant of this first solution, the rotating element has an irregular shape so that the outer edge33,303in contact with stud9is not perfectly circular. Thus, the edge in contact with stud9includes a substantially triangular set back portion and forms a gentle slope. When the rotating element is rotated and secured in the housing, this configuration makes it possible to even out the increase in stress applied to stud9in order to lock it.

In a second solution seen inFIGS. 14 to 16, the stud is mounted in an adjustable position on the stud-holder. In this solution, the rotating element is thus provided with a notch35whose dimensions are similar to those of the stud so that the latter can be placed therein. Housing500further includes a through portion so that stud9can pass therethrough and emerge in housing500, so that the stud can be fixed to the balance spring and inserted in notch35. This notch35for stud9can be arranged on outer edge303of ring300or on inner edge304. This through portion will have the shape of a circular groove.

During assembly, stud9is initially placed in notch35of the rotating element. Then, the rotating element is fixed in its housing500, by engaging male interface701with female interface702. The rotating element is then rotated and causes a contact between peripheral rim511and stud9or between inner rim512and the stud. The stud is thus pressed and locked. The circular groove shape of the through portion of housing bottom513allows stud9to be placed in the notch of the rotating element and rotatable assembly of the latter.

Of course, it will be understood that the ring notch may or may not protrude so as to gain size.

In a variant of this second solution, the peripheral or inner rim has an irregular shape so that it is not perfectly circular. Thus, the peripheral or inner rim includes a substantially triangular set back portion and forms a gentle slope. When the rotating element is rotated and secured in the housing, this configuration makes it possible to even out the increase in stress applied to the stud in order to lock it.

In a first variant of the second embodiment or of the third embodiment seen inFIGS. 17 to 19, it is possible to envisage that housing500is arranged on the lower face of the cock. Indeed, cock5has an upper face, which is visible when cock5is assembled, and a lower face. This lower face is generally the face on which the balance staff is fixed. The housing of cock5is thus arranged on this lower face. In the second and third embodiments, this means that it is not necessary to have a partly through bottom in order for the stud to be fixed in the rotating element notch and fixed to the balance spring. A perfectly smooth visible face of the cock is thus obtained for forming decorations.

In a second variant of the second embodiment or of the third embodiment seen inFIGS. 20 to 23, there is provided a shock absorber system100. The latter may take a conventional form, that is to say a setting in which a jewel with a hole and an endstone are arranged, or the form of a single jewel. This single jewel is provided with a recess for cooperating with the balance staff and may be force-fitted into the hub hole or mounted via an elastic ring. Shock absorber system100could also take the form of a disc provided with elastic arms.

In the case where the housing is arranged on the visible face of the cock seen inFIG. 20, the underside of the housing bottom includes a recess in which said shock absorber system100is arranged. If the housing is provided with a protruding portion formed by the inner rim, the recess for shock absorber system100will be placed on this protruding portion or central island allowing for perfect centring.

In the case where the housing is arranged on the non-visible face of the cock, there are several possibilities.

In the case of a housing provided with an inner rim forming a protruding portion or central island as seen inFIG. 22, the recess for the shock absorber system will be created on this central island.

In the case where the housing is provided with a peripheral rim and a bottom and where the rotating element is a hub as seen inFIG. 21, the recess for shock absorber system100will be arranged on said hub.

In the case where the housing is provided with a peripheral rim511and a bottom513and where the rotating element is a ring300as seen inFIG. 23, the recess for shock absorber system100will be arranged on the bottom of said housing500, such that the balance staff bearing the balance spring passes through said ring300.

In a variant of the different embodiments in which the rotating element is a ring and as seen inFIG. 24, rotating ring300is a ring with several levels333. More specifically, the rotating ring includes2levels333a,333b. To achieve this, rotating ring300would be similar to a tube having a constant internal diameter and a variable external diameter. First level333ahaving the largest diameter would carry male interface702, whereas second level333bhaving the smallest diameter would be used for locking stud9. This variant allows the attachment portion of the stud and the attachment portion in the housing to be separated and to bring the stud closer to spinal.

For rotatable mounting of the rotating element in the different embodiments, male interfaces71,701and female interfaces72,702thus cooperate with each other in order to mount the central hub in the housing by a rotational motion of the hub relative to the housing.

According to a first alternative embodiment, the rotatable mounting is a bayonet fitting. To achieve this, female interface702is formed by at least one cavity comprised in the thickness of the peripheral rim. This cavity is formed by a countersink, which is parallel to said central hub axis and open on the upper surface, and a blind slot, which is secant with said first countersink and opposite to the upper surface. This slot is used to lock the rotating element in a bayonet fitting.

Male interface71,701, located on the rotating element, consists of at least one protruding portion. This protruding portion is located on the outer edge of the rotating element. The protruding portion is arranged to cooperate with the female interface.

The rotating element is mounted in the housing such that the protruding portions can be inserted in the countersink The rotating element can then be inserted in the housing. When the rotating element reaches an abutment position, the protruding portions must be facing the slots. Consequently, a movement of rotation is effected to insert the protruding portions into said slots and to fix said rotating element in the cock.

According to a second alternative, the rotatable mounting is a screw mounting. Thus, the female interface is formed by a screw pitch comprised in the peripheral rim. The male interface, located on the rotating element, also consists of a screw pitch. The screw pitch is arranged to cooperate with the female interface.

Of course, other types of assembly may be used, such as for example pressing-in or adhesive bonding, but they cannot be disassembled like the bayonet fitting or screws.

It will be clear that various alterations and/or improvements and/or combinations evident to those skilled in the art may be made to the various embodiments of the invention set out above without departing from the scope of the invention defined by the annexed claims.