CH712519A1 - Engine body for timepiece. - Google Patents

Abstract

Engine member (1) for a timepiece comprising: a mainspring (7); a drum (5) delimiting an outer wall of a housing housing said motor spring (7), an outer end of said motor spring (7) being bonded to said drum (5), said drum (5) being arranged to pivot about an axis of rotation; a toothed wheel (11) integral with a plug (9) to which an inner end of said motor spring (7) is connected; wherein an open face of said housing is intended to be closed by being positioned facing a fixed element (3) of the timepiece against which said drum (5) is intended to be mounted. According to the invention, said drum (5) has the shape of a toothed annular ring.

Description

Description TECHNICAL FIELD [0001] The present invention relates to the field of watchmaking. It relates, more particularly, a motor unit with reduced space.

State of the art [0002] Currently, the most commonly used motor member in mechanical timepieces is the barrel. Typically, a barrel comprises a hollow drum comprising a cylindrical wall closed on one side by a bottom integrally with it, and on the other side by a cover, to form a housing for a spiral spring. The outer end of the spiral spring is connected by a fixed or sliding flange to the cylindrical wall of the drum, and the inner end of the spring is connected to a bung associated with a barrel shaft. The outer wall of the drum is typically provided with a toothing to drive a finishing train, and the shaft is secured to a ratchet wheel, which is used for winding the spring. It is also known to drive the finishing gear through the shaft and refit the spring via the drum. On the other hand, smooth drums, with no teeth, are known which drive the finishing gear through a chain and a rocket system.

The conventional barrel mentioned above is mounted on the frame by its center, including directly or indirectly through the shaft. This arrangement is relatively bulky, and requires a certain height between the frame members located on either side of the barrel to ensure that the barrel does not come into contact with neighboring components.

[0004] Solutions to this problem have already been proposed in the prior art. By way of example, patent CH 26 510 omits the drum cover, the housing for the spring being delimited on one side by the bottom of the drum, and on the other side by a frame member of the movement, in particular the plate .

An even more compact solution has been proposed in document CH 46 863. The motor of this document proposes a drum also closed on one side by a frame member, wherein the shaft came from a piece with a wheel which is located totally in the thickness of this frame member, in a recess provided in the latter.

The drums of all embodiments mentioned above are supported by their center, which requires that the drum has a bottom integral with its side wall. The document CH 334 702 discloses several variants of barrels in which the drum consists of a ring guided to its peripheral wall by means of three pairs of rollers distributed around the periphery of the drum. This drum has neither cover nor bottom, and the housing for the mainspring is defined on its lower and upper faces by bridges of the movement frame.

Although the barrels disclosed in the latter document lead to a significant height reduction compared to a conventional barrel, the use of pairs of rollers located around the drum increases the diameter of the barrel, and increases the complexity of the organ engine. Moreover, the rollers are rotary, and therefore require axes of rotation. There are therefore four axes (the shaft and those of the three pairs of rollers) which must be aligned when mounting the barrel bridge on the plate, which causes some difficulty in its assembly.

An object of the invention is therefore to provide a motor member in which the aforementioned defects are at least partially overcome.

Disclosure of the invention [0009] More specifically, the invention relates to a motor unit for a timepiece which comprises a motor spring such as a spiral spring, and a drum defining an outer wall of a housing housing said housing. motor spring. The outer end of the motor spring is connected to the drum, which is arranged to pivot about an axis of rotation.

The motor member further comprises a toothed wheel, which can for example be used as a ratchet wheel, integral with a plug to which an inner end of said motor spring is connected.

A face of said housing is intended to be defined by a fixed element of said timepiece against which said drum is intended to be mounted, such as a frame member, a bottom, or an ice.

According to the invention, said drum has the shape of a toothed annular ring. This construction results in a significant reduction in size compared with the barrels of the prior art. The combination of a toothed wheel integral with the bung (and therefore compact) with a drum formed of a toothed annular ring and thus lacking not only cover but also bottom, allows a very thin construction.

Advantageously, said plug and said toothed wheel can be from a piece.

Advantageously, said drum and said motor member can be from a piece, which reduces the number of parts of the drive member and facilitates its mounting.

Advantageously, the other side of said housing, that is to say the one opposite to the fixed element, is defined by said toothed wheel, which minimizes the number of components and support elements necessary for the construction of the drive member, and thus increases its simplicity and compactness.

Advantageously, said drum is positioned and guided radially and axially by means of a barrel bridge. As such, the barrel bridge may comprise at least one guide member projecting from said barrel bridge in a direction substantially parallel to said axis of rotation, and therefore perpendicular to the plane of the motor member. At least one guide member is preferably fixed, but may also be movable. A compact guide system is thus proposed, which is easy to assemble because the guide elements are carried by the barrel bridge and therefore do not require any additional support. In order to cooperate with the guide member, the drum may comprise a shoulder arranged to abut against the latter in order to position it radially and axially relative to the bridge.

In order to make the motor member even more compact, particularly with regard to its diameter, said at least one guide member may be entirely within a geometric locus consisting of a cylinder of height infinite whose diameter is defined by the tops of the toothing of said drum. In other words, the guide member does not extend radially beyond the tops of the teeth of the drum.

Advantageously, said at least one guide member may comprise a plurality of studs, preferably stone. The use of studs, which are fixed single elements that do not rotate, requires no axis of rotation for the or the guide members, which makes the assembly simple and easy to implement. Alternatively, ball rollers or the like can be used, at the cost of increasing the complexity and the number of components.

Advantageously, said drum may comprise a plurality of stones or guide pads for abutting against said fixed element. A low friction drum stop system is thus proposed.

Advantageously, in another variant, said drum is supported by a ball bearing. The friction which is experienced by the drum during its rotations can be minimized, while maintaining the thickness of the motor member to a minimum. The ball bearing can be bidirectional, or unidirectional. This latter possibility allows the drum to function as a ratchet, without requiring any pawl, for the case where the drive member is raised by the drum.

Advantageously, said ball bearing comprises a first groove lying on the outer wall of said drum and a second groove facing said first groove, said second groove lying on the inner wall of an outer ring arranged to be fixed. said fixed element, the grooves thus defining an annular cavity. A plurality of balls are housed in this annular cavity. A compact construction is thus proposed.

Advantageously, the motor member as defined above is integrated with a clockwork movement that comprises said fixed element.

Advantageously, said toothed wheel can be pivotally mounted on a fixed shaft extending from the fixed element or the barrel bridge.

Advantageously, said fixed element may be a frame member of a watch movement of said timepiece such as a platinum or a bridge, or an ice cream that includes a timepiece side bottom or dial side, or a background that includes said timepiece.

In the case where the fixed element is an ice of the timepiece, said barrel bridge may be integrated with a frame member or a background that includes said timepiece.

BRIEF DESCRIPTION OF THE DRAWINGS [0026] Other details of the invention will appear more clearly on reading the description which follows, made with reference to the appended drawings in which: FIG. 1 is a sectional view of a first variant of a motor member according to the invention; fig. 2 is an enlarged view of the left half of FIG. 1; fig. 3 is a perspective view of the driving member of FIG. 1; fig. 4 represents the barrel bridge in perspective, seen from both sides; fig. 5 represents the drum in perspective, seen from both sides; fig. 6 shows a part of the frame member on which the driving member of FIG. 1 is mounted; fig. 7 shows the toothed wheel of the first variant in perspective, seen from both sides; fig. 8 is a sectional view of a second variant of a motor member according to the invention; fig. 9 is an enlarged view of the left half of FIG. 7; fig. 10 is an exploded view of said second variant of a motor member; fig. 11 is a perspective view of a variant of the drum and the mainspring; fig. 12 is a perspective cut view of yet another variant of a motor member according to the invention; fig. 13 is an enlarged view of a detail of FIG. 12; and FIG. 14 is a plan view of the variant of FIG. 12.

Embodiments of the Invention [0027] FIGS. 1 to 7 show a first variant of a motor unit 1 according to the invention. The motor member 1 is mounted on a fixed element 3 of a timepiece in which the motor member is implemented. This fixed element 3 may be a plate or a bridge, or a bottom on which the motor member 1 is directly or indirectly mounted.

The motor member comprises a drum 5 having a peripheral toothing 6. This drum 5 has no cover and bottom, and defines a cylindrical housing in which is disposed a motor spring 7. The latter is of conventional form, in spiral, and is connected at its outer end to the inner wall of the drum 5, and at its inner end to a bung 9. The latter came in one piece with a gear wheel 11 which serves as a ratchet wheel in the mode of illustrated embodiment, but which can also be used for driving the wheels, the drum 5 serving as a ratchet in such a case. The toothed wheel 11 extends in superposition of the spring 7, and serves as a barrel cover, but the plug may consist of a separate piece secured to the toothed wheel 11. The plug 9 is pivoted about a fixed shaft 13 and is held on the latter by means of a screw 15 or the like which bears against the toothed wheel 11. As best seen in FIG. 6, the bung 9 comprises a hook 9a for connection with the inner end of the motor spring 7 formed directly in the bung 9, for example by means of wire EDM or sinking. Alternatively, it can be done by broaching or traditional milling.

The toothed wheel 11 serves as a lid for the barrel, which is not integral in rotation with the drum 5, as known for example in the document CH 28 684.

On its opposite side to the toothed wheel 11, the barrel is closed by a surface of the fixed element 3. The drum 5 as such is devoid of bottom and lid, and is only a ring single toothed.

The drum 5 is positioned axially and radially by guide elements 17 distributed around the periphery of the drum 5. As best seen in FIGS. 3 and 4, these guide elements 17 are, in the variant shown, studs, here made in the form of stones, driven in a barrel bridge 19, and which abut against a shoulder 21 provided on the drum 5. A benefit of the use of stones, such as rubies, for studs is the low coefficient of friction of this material, but other materials are possible. For example, the pads 17 may be of hard metal, polymer or ceramic, and in the case of metal, may be integral with the barrel bridge 19. Alternatively, the pads may be replaced by a continuous or discontinuous surface of the barrel bridge 19, or by ball bearings. The studs 17 extend from the barrel bridge 19 in a direction parallel to the axis of rotation of the drum 5, and do not extend radially beyond the peripheral toothing 6 of the drum 5. In fact, the elements of FIG. 17 are inscribed in the diameter of the drum 5, which reduces the bulk in the plane of the drum 5 relative to the document CH 334 702 mentioned above.

In principle, the drum 5 can simply abut against the surface of the fixed element 3 and slide on the latter during its pivoting. However, in order to reduce friction, the drum 5 comprises guide stones 23 driven into corresponding housings and extending towards the fixed part 3. These guide stones reduce the contact surface between the drum 5 and the part fixed 3 as well as the coefficient of friction.

The barrel bridge 19 also comprises an armature pawl 25 which cooperates in a known manner with the toothing of the toothed wheel 11. Furthermore, the underside of the barrel bridge 19 comprises a recess 27 which serves to enable a mobile of the work train (not shown) to mesh with the peripheral toothing 6 of the drum 5.

The barrel bridge 19 is fixed on the fixed element 3 by means of screws 29 engaged in threaded tubes 31, which project from the upper face of the fixed element 3. These tubes 31 serve as centering studs for the barrel bridge 19, and ensure its positioning on the fixed element 3. Alternatively, the bridge can be fixed to the fixed element 3 by means of other fastening methods such as clipping, snapping or gluing.

Figs. 7 to 8 illustrate a second variant of a motor unit 1 according to the invention. This variant differs from that of FIGS. 1 to 7 mainly in that its construction is the opposite of that of the latter.

In this variant, the fixed element 3 is an ice, which can be located on the dial side or the bottom side, and defines the housing of the motor spring 7 on one of its sides. The barrel bridge 19 may be a separate element, secured to the plate or to the bottom, or may come from a room with one of these. The term "bridge" used rather means a functional part of the structure of the motor member 1 which may be part of another element such as a plate or a bottom. The barrel bridge 19 of this variant comprises a hollow in its bottom, in which is located the toothed wheel 11, which is pivoted about a fixed shaft 13 that includes said bridge 19. The axial positioning of the toothed wheel 11 is provided on one side by a stop 33, and on the other side by ice 3.

The drum 5 is superimposed on the toothed wheel 11, and is guided in rotation and axially by guide elements 17 similar to those of the first variant, and which also extend from the barrel bridge 19 in the direction of the fixed element 3 in a direction parallel to the axis of rotation of the drum 5. As for the other variant, the guide elements 17 cooperate with the shoulder 21 located on the drum 5 to ensure the positioning of the latest.

The guide elements 17 are located in blind holes 35 which are deeper than necessary to receive the guide elements 17 to allow the watchmaker to adjust the height of the latter according to his needs. Alternatively, the blind holes 35 may have a depth sufficient to receive the guide elements 17 to the bottom of the holes 35.

On the other side of the drum 5, the guide of the latter is simply provided by the fixed member 3 against which the drum 5 abuts. However, it is conceivable to provide guide stones 23 in the drum which extend in the direction of the ice 3 in a similar manner to the variant of FIGS. 1 to 7.

The mounting of this variant is carried out in the following order: - mounting of the toothed wheel 11 on the fixed axis 13; - Mounting the drum 5 in superposition of the toothed wheel 11; - Mounting the motor spring 7 in the drum 5 and hooks it on the bung 9 of the toothed wheel 11; - mounting the ice.

In a variant not shown, the axial positioning of the toothed wheel 11 can be provided not by the glass 3, but by the drum 5 which can serve as an axial stop.

FIG. 10 illustrates a variant of the drum 5 and the motor spring 7 which can be implemented in connection with all the aforementioned embodiments. The drum 5 and the motor spring 7 form a one-piece assembly, come from a room. The inner end of the mainspring 7 also comprises a ferrule 7a allowing a kinematic connection with the toothed wheel 11, but this ferrule 7a can of course be omitted. In the example illustrated, the ferrule comprises a polygonal opening, but other known shapes are also possible. A motor spring 7 of this type may be made of metal, or of silicon-based material (for example amorphous, monocrystalline or polycrystalline silicon, its oxide, carbide or monocrystalline or polycrystalline nitride), alumina or polymer. , a composite or the like.

Since the construction of the motor member 1 of the invention comprises many contact surfaces between moving parts, it could be advantageous to provide polishing or fine diamond contact surfaces, or perform a treatment surface such as a deposit of DLC (diamond-shaped carbon), nanostructuration, teflonnage, electroplating or ion implantation on one or more surfaces intended to be rubbed.

Figs. 12 to 14 further illustrate a variant of a motor unit 1 according to the invention. In this variant, the toothed wheel 11 is supported on a fixed shaft 13 in a manner similar to the variant of FIGS. 1 to 3, and the housing for the mainspring is defined on both sides by the toothed wheel 11 and a fixed element 3 of the timepiece, such as a frame member.

However, the drum 5 is held in its axial and radial positions by means of a ball bearing 37. This ball bearing 37 consists of a first groove 38a provided on the outer wall of the drum 5, and a second groove 38b formed in the inner face of an outer ring 39. The two grooves 38a, 38b are facing one another to define a cavity, and balls (not shown) take place in this cavity in a generally known manner.

In the illustrated variant, the first groove 38a is formed of a first beveled surface 5a provided on the outer face of the drum 5, which is adjacent to a second beveled surface 41a which is provided with an inner ring 41. The latter is driven, glued, welded or otherwise secured to the outer face of the drum 5, but it is also possible to form the first groove 38a directly in the body of the drum 5, which would therefore be monobloc.

The outer ring 39 is held in place by a bridge 19 and screws 43, which hold it against a shoulder 45 provided on the fixed member 3 which is thus fixed.

The drum 5 is thus suspended by the ball bearing 37, and does not come into contact with the fixed element 3 nor with the gear wheel 11. Therefore, and unlike the other variants described above no additional guide is needed. The friction experienced by the drum during its pivoting can thus be reduced to a minimum value. Moreover, this variant has an unusually thin thickness.

Figs. 12 to 14 also illustrate the arrangement of the gears with the toothed wheel 11 and with the drum 5. It is clearly seen a reference 47 which is in the same plane as the toothed wheel 11 which meshes with the latter,

Claims (18)

and another referral 49 which is in the same plane as the toothing 6 of the drum 5 and also meshes with it. The references 47, 49 consequently pass on either side of the outer ring 39. This arrangement also has other possibilities for other construction variants. In the first place, the same considerations with respect to the configuration of the mainspring 7 exposed above (one-piece spring with the drum 5, conventional spring, etc.) also apply here. It is also possible to remount the motor member by its drum 5 and use the toothed wheel 11 as a power take-off for the movement. In the latter case, if the ball bearing 37 is unidirectional type, the drive member can be raised by the drum 5 without requiring any pawl, thereby reducing the number of components used in the construction. Moreover, this arrangement eliminates the surge during the winding of the mainspring 7 by the dead angle of a unidirectional bearing. Although the invention has been described in connection with particular embodiments, it is obvious that it is not limited thereto and that it includes all the technical equivalents of the means described and their combinations if these fall within the scope of the invention as defined by the claims. claims Motor unit (1) for a timepiece comprising: - a mainspring (7); - a drum (5) defining an outer wall of a housing housing said motor spring (7), an outer end of said motor spring (7) being connected to said drum (5), said drum (5) being arranged to pivot about an axis of rotation; - A toothed wheel (11) integral with a plug (9) to which an inner end of said motor spring (7) is connected; wherein an open face of said housing is intended to be closed by being positioned facing a fixed element (3) of the timepiece against which said drum (5) is to be mounted, characterized in that said drum (5) has the shape of a toothed annular ring. 2. Engine member (1) according to claim 1, wherein said plug (9) and said toothed wheel (11) are integrally formed. 3. Engine member (1) according to one of claims 1 and 2, wherein said housing has a second open face opposite which is arranged said toothed wheel (11). 4. Engine member (1) according to one of claims 1 to 3, wherein said drum (5) and said motor member (7) came from a room. 5. Engine member (1) according to one of claims 1 to 4, wherein said drum (5) is positioned and guided radially-axially and via a barrel bridge (19) that includes said body motor (1). The engine member (1) according to claim 5, wherein said barrel bridge (19) comprises at least one guide member (17) projecting from said barrel bridge (19) in a direction substantially parallel to said axis. of rotation. 7. Motor member (1) according to claim 6, wherein said drum comprises a shoulder (21) arranged to abut against said at least one guide member (17). 8. Motor member (1) according to one of claims 6 and 7, wherein said at least one guide member (17) is entirely within a geometric locus consisting of a cylinder of infinite height whose diameter is defined by the tops of the toothing (6) of said drum (5). 9. Engine member (1) according to one of claims 6 and 7, wherein said at least one guide member (17) comprises a plurality of pads, preferably stone. 10. Engine member (1) according to one of claims 1 to 9, wherein said drum (5) comprises a plurality of guide stones (23) for abutting against said fixed member. 11. Engine member (1) according to one of claims 1 to 4, wherein said drum (5) is supported by a ball bearing (37). The drive member (1) according to claim 11, wherein said ball bearing comprises a first groove (38a) located on the outer wall of said drum and a second groove (38b) facing said first groove (38a), said second groove (38b) being located on the inner wall of an outer ring (39) arranged to be fixed to said fixed member (3), a plurality of balls being housed in the cavity formed by said grooves (38a, 38b). Clock movement comprising a motor unit (1) according to one of claims 1 to 12. Clock movement according to claim 13, wherein said toothed wheel (11) is pivotally mounted on a fixed shaft (13) extending from one of the fixed element (3) or the barrel bridge (19). . 15. Watch movement according to one of claims 13 to 13, wherein said fixed element (3) is a frame member of said movement. 16. Timepiece comprising a watch movement according to one of claims 13 to 15. 17. Timepiece according to claim 16 wherein said fixed element is an ice (3) that includes said timepiece or a background that includes said timepiece. 18. Timepiece according to claim 17, wherein the fixed element (3) is said ice, and wherein said barrel bridge (19) is integrated with a frame member or a bottom that includes said piece of housing. watchmaking.