HK1210525B - Timepiece barrel - Google Patents

Description

Clock barrel

Technical Field

The invention concerns a timepiece barrel intended to be pivotally assembled between a bottom plate and a bridge and comprising at least one spring housed between a cover and a pivoting barrel and hooked between said barrel and a arbour at the outer and inner ends of said spring. Said arbour pivoting integrally with a ratchet about a pivot axis, said barrel comprising a single-piece subassembly coaxial with said pivot axis and containing said arbour and a hub provided with a flange for limiting the axial wobble of said barrel wheel, wherein said flange carries a pivoting drive mechanism for driving the pivoting of said ratchet, said ratchet being axially free in the direction of said pivot axis, wherein the axial wobble of said barrel wheel is limited by the lower abutment of the upper surface of said barrel wheel with respect to said single-piece subassembly, the upper surface of said barrel wheel is limited by the lower shoulder of said single-piece subassembly, the axial wobble of said ratchet is limited by the lower abutment of the upper surface of said ratchet with respect to said bridge, the upper surface of said ratchet is limited by a threaded portion or by the lower surface of said bridge or by the lower surface of a jewel bearing included in said bridge, wherein axial wobble of the ratchet is limited by a lower surface of the ratchet in an abutting manner with respect to the barrel wheel, a lower surface of the ratchet is limited by an upper surface of the barrel wheel, axial wobble of the cover is limited by a lower surface of the cover in an abutting manner with respect to the bottom plate, and a lower surface of the cover is limited by an upper surface of the bottom plate or an upper surface of a jewel bearing included in the bottom plate.

The invention also concerns a timepiece movement comprising at least a bottom plate, a bridge and a barrel of the above type.

The invention also relates to a watch comprising a movement of the above type.

The present invention relates to the field of horological mechanisms, and more particularly to a mainspring barrel, striking barrel or similar type of energy storage mechanism.

Background

In order to improve the power reserve by increasing the number of turns of the mainspring fixed at its inner end to a core formed by a generally cylindrical arbour or by a more solid hub, one solution consists in reducing the diameter of the barrel arbour and of the relative hub, so as to increase the space available for the mainspring inside said barrel wheel.

The ratio of the radius of the core to the thickness of the balance spring is generally between 10 and 20, and the invention proposes to reduce this ratio to below 10, and preferably to within a range between 5 and 10.

The size cannot be set according to the grass rate; if the diameter of the core is too small, there is a risk of damage.

In a traditional barrel construction, the ratchet is mounted axially on the barrel arbour or core by means of a square, wherein the ratchet is usually fixed by an axial screw. The dimensions of the screw and square thus define the minimum diameter of the pivot shoulder. The step connected to the pivot shoulder limits the axial play/clearance (shake) of the core or arbor relative to the base plate or splint carrying the gemstone or similar element.

In particular, merely reducing all dimensions is not sufficient, since the cross section of the material will not be sufficient to ensure fatigue resistance.

The problem is therefore to adjust the diameter as small as possible in order to allow the largest possible power reserve while maintaining the ratchet-driven rigidity.

U.S. patent application No. 804728A in the name of JOHNSON describes a barrel whose arbour carries a threaded hub which in turn carries a mainspring. Two parts are therefore necessary for the internal retention of the spring. The drum is guided by jewel bearings which are not integral with the mandrel. The winding ratchet wheel is positioned on the other side of the barrel clamp plate. The portion of the square carrying the drive ratchet is not formed by the flange, but by the end of the arbour projecting beyond said clamping plate on the opposite side of the drum.

Swiss patent application No. 83330a in the name of BEAULIEU WATCH CO describes a barrel wheel without a lid, comprising a core screwed onto a mandrel. The drum is loosely fitted onto the mandrel between the core and the shoulder of the mandrel. Here, two parts are also required for the internal retention of the spring.

Swiss patent application No. 295135a in the name of BRAC AG describes a drum whose bottom plate comprises a supporting threaded portion for a ratchet.

Disclosure of Invention

The invention proposes to improve the design of known barrels to achieve a large power reserve by achieving a high level of rigidity, in particular with respect to the ratchet, while maintaining a reduced number of components and acceptable manufacturing costs or costs that are preferably more economical than the known barrels

The invention therefore concerns a timepiece barrel for pivotal assembly between a base plate and a bridge and including at least one barrel spring housed between a cover and a pivotal barrel drum and hooked between the barrel drum and a arbour at the outer and inner ends of the barrel spring, the arbour pivoting integrally with a ratchet about a pivot axis, the barrel including a single-piece subassembly coaxial with the pivot axis and containing the arbour and a hub provided with a flange for limiting the axial oscillation of the barrel drum, wherein the flange carries a pivotal drive mechanism for driving the pivoting of the ratchet, the ratchet being axially free in the direction of the pivot axis, wherein the axial oscillation of the barrel drum is limited by the abutment of an upper surface of the barrel drum, relative to the barrel assembly, the upper surface of the barrel drum being limited by a lower shoulder of the single-piece subassembly, wherein the axial wobble of the ratchet is limited by the lower abutment of the upper surface of the ratchet with respect to the clamping plate, the upper surface of the ratchet is limited by the threaded portion or the lower surface of the clamping plate or the jewel bearing comprised in the clamping plate, and the axial wobble of the ratchet is limited by the upper abutment of the lower surface of the ratchet with respect to the barrel wheel, the lower surface of the ratchet is limited by the upper surface of the barrel wheel, and the upper abutment of the lower surface of the cover with respect to the bottom plate, the lower surface of the cover is limited by the upper surface of the bottom plate or the jewel bearing comprised in the bottom plate, characterized in that the balance spring is made of a multiphase cobalt nickel chromium-based alloy comprising 44% to 46% cobalt, 20% to 22% nickel, 17% to 19% chromium, 4% to 6% iron, 3% to 5% of tungsten, 3% to 5% of molybdenum, 0 to 2% of titanium, 0 to 1% of beryllium, and having a young's modulus between 200 and 240GPa and a shear modulus between 80 and 100GPa, the balance spring preferably having a width-to-thickness ratio between 3 and 23, and the ratio between the maximum radius of the bearing shoulders of the balance spring of the mandrel and the thickness of the balance spring being between 3 and 9.

According to one feature of the invention, said one-piece subassembly pivots in a hole of said clamping plate or a jewel bearing comprised in the clamping plate on an upper shoulder whose travel is limited by a lower surface of said clamping plate or said jewel bearing, said ratchet being comprised between said upper and lower shoulders comprised in said one-piece subassembly on said hub, said lower shoulder limiting the travel of an upper surface of said drum, said drum pivoting with a cylindrical shoulder of said hub in a hole comprised in the drum.

According to one feature of the invention, the lower shoulder is formed by a lower abutment surface of the flange.

According to one feature of the first variant of the invention, the flange separates the barrel wheel from the ratchet wheel and comprises an upper abutment surface for abutment of a lower surface of the ratchet wheel, and carries the pivoting drive mechanism beyond the upper abutment surface on the side opposite the lower abutment surface.

The invention also concerns a timepiece movement comprising at least a bottom plate, a bridge and a barrel of the above type.

The invention also relates to a watch comprising a movement of the above type.

Drawings

Other features and advantages of the present invention will become apparent from the following detailed description when read in conjunction with the accompanying drawings, in which:

fig. 1 shows a schematic section through its pivot axis of a barrel according to a first variant of the invention.

Fig. 2 shows a schematic sectional view through its pivot axis showing a barrel according to a second variant of the invention.

Fig. 3 shows a schematic block diagram of a timepiece comprising a movement, which in turn comprises a barrel according to the invention.

Detailed Description

The present invention relates to the field of horological mechanisms, and more particularly to a mainspring barrel, striking barrel or similar type of energy storage mechanism.

The invention therefore concerns a timepiece barrel 1, this barrel 1 being intended to be pivotally assembled between a bottom plate 9 and a plate 5 and comprising at least one spring 7. Said spring 7 is housed between the cover 8 and the pivoting drum 6 and is hooked between the drum 6 and the arbour 3 at the outer and inner ends of said spring. The spindle 3 is mounted to pivot integrally with the ratchet 2 about a pivot axis D.

According to the invention, barrel 1 comprises a single-piece subassembly 10 coaxial with arbour 3 and comprising arbour 3 and hub 4 provided with a flange 17 for limiting the axial oscillation of barrel wheel 6. This flange 17 carries a pivoting drive mechanism 42, such as a flat, square or similar structure, for driving the ratchet 2 to pivot on the complementary drive mechanism 23. This ratchet 2 is axially free in the direction of the pivot axis D.

This one-piece subassembly 10 pivots on the clamping plate 5 or on the upper shoulder 13 in the bore 51 of the jewel bearing 52 included in the clamping plate 5 and includes the upper shoulder 11, the travel of which upper shoulder 11 is limited by the lower surface 53 of the clamping plate 5 or jewel bearing 52. The ratchet 2 is comprised between an upper shoulder 11 and a lower shoulder 12, which upper and lower shoulders 11, 12 are comprised in a single piece subassembly 10 on the hub 4. Lower shoulder 12 limits the travel of upper surface 61 of drum 6. Drum 6 pivots with cylindrical shoulder 41 of hub 4 in a hole 62 contained in the drum. In the first variant of fig. 1, said lower shoulder 12 is formed by a lower abutment surface 16 of a flange 17. In this same variant, the flange 17 separates the barrel wheel 6 from the ratchet 2 and comprises an upper abutment surface 15 for supporting the lower surface 22 of the ratchet 2. The flange 17 carries the pivot drive 42 on the side opposite the lower bearing surface 16 and projects beyond the upper bearing surface 15 on the side of the clamping plate 5.

The spindle 3 comprises a preferably cylindrical shoulder 31, the diameter of which is preferably smaller than the diameter of the cylindrical shoulder 41 of the hub 4. Arbour 3 carries spring 7 on its shoulder 31 or on a hook 32 included in arbour 3 around this shoulder 31, spring 7 being fixed on this shoulder by friction or welding. The spindle 3 is pivotally mounted in a hole 91 of the base plate 9 or of a jewel bearing 92 included in the base plate 9. In a preferred embodiment, the shoulder 31 extends in said hole 91 or in said jewel bearing 92 and forms a pivot surface.

Drum 6 carries a cover 8 which is preferably, but not necessarily, pivoted integrally with drum 6, and whose hole 81 cooperates with shoulder 31 of arbour 3. The travel of the lower surface 82 of the cover 8 is limited by the upper surface 93 of the base plate 9 or of a jewel bearing 92 accommodated in the base plate 9, wherein the hole 91 of the base plate 9 or of the jewel bearing 92 acts as a pivot for the shoulder 31 of the spindle 3.

Axial play of barrel wheel 6 is limited by upper surface 61 of barrel wheel 6 relative to the upper portion of ratchet 2, and upper surface 61 of barrel wheel 6 is limited by lower shoulder 12 of one-piece subassembly 10.

The axial wobble of the ratchet 2 is limited by the above abutment of the upper surface 11 of the single-piece subassembly 10 with respect to the clamping plate 5, the upper surface 11 of the single-piece subassembly 10 being limited by the lower surface 53 of the clamping plate 5 or of a jewel bearing 52 comprised in the clamping plate 5.

Axial play of the cover 8 is limited by the above abutment of the lower surface 82 of the cover 8 with respect to the base plate 9, the lower surface 82 of the cover 8 being limited by the upper surface 93 of the base plate 9 or of a jewel bearing 91 included in the base plate 9.

Mainspring can be made of a variety of materials: carbon steel, stainless steel "(Nwaflex clockwork) ", silicon, DLC (diamond-like carbon), quartz, glass, or the like. In a particular application, balance spring 7 is made of a multiphase cobalt nickel chromium based alloy comprising 44% to 46% cobalt, 20% to 22% nickel17 to 19% chromium, 4 to 6% iron, 3 to 5% tungsten, 3 to 5% molybdenum, 0 to 2% titanium, 0 to 1% beryllium, and having a young's modulus between 200 and 240GPa and a shear modulus between 80 and 100 GPa. The spring 7 preferably has a width to thickness ratio of between 3 and 23, more particularly between 9 and 21.

Likewise, the maximum radius of shoulder 31 of arbour 3 relative to pivot axis D (without taking account of any additional thickness of hook 32) is less than nine times the maximum thickness of balance spring 7, said arbour being made of steel or stainless steel, for example 4C27A hardened steel (also known according to different standards as 1.4197, ASTM 420F or DIN X22CrMoNiS 131). In particular, with the embodiment shown, a ratio of the maximum radius of shoulder 31 of arbour 3 to the thickness of balance spring 7 of between 3 and 9 and preferably between 4 and 6, preferably close to 5, can be obtained.

Fig. 1 and 2 show two preferred but non-limiting variants, which are explained in detail below:

first variant of fig. 1:

axial play of drum 6 is limited by upper surface 61 of drum 6 abutting in relation to single-piece subassembly 10, and upper surface 61 of drum 6 is limited by lower surface 12 of single-piece subassembly 10.

The axial wobble of the ratchet 2 is limited by the lower abutment of the upper surface 21 of the ratchet 2 with respect to the clamping plate 5, the upper surface 21 of the ratchet 2 being limited by the threaded portion 54 or the clamping plate 5 or the lower surface 53 of the jewel bearing 52 comprised in the clamping plate 5.

Axial wobble of the ratchet 2 is limited by the lower surface 22 of the ratchet 2 in an upper abutment with respect to the one-piece subassembly 10, the lower surface 22 of the ratchet 2 being limited by the upper abutment surface 15 of the flange 17 of the one-piece subassembly 10.

Axial play of the cover 8 is limited by the lower surface 82 of the cover 8 in an upper abutment with respect to the base plate 9, the lower surface 82 of the cover 8 being limited by the upper surface 93 of the base plate 9 or of a jewel bearing 91 included in the base plate 9.

Second variant of fig. 2:

axial wobble of drum 6 is limited by upper surface 61 of drum 6 in lower abutment with respect to single-piece subassembly 10, and upper surface 61 of drum 6 is limited by lower surface 12 of single-piece subassembly 10.

The axial wobble of the ratchet 2 is limited by the lower abutment of the upper surface 21 of the ratchet 2 with respect to the clamping plate 5, the upper surface 21 of the barrel wheel 2 being limited by the threaded portion 54 or the clamping plate 5 or the lower surface 53 of the jewel bearing 52 comprised in the clamping plate 5.

The axial play of the ratchet 2 is limited by the lower surface 22 of the ratchet 2 abutting against the barrel wheel 6 in an upper abutment, and the lower surface 22 of the ratchet 2 is limited by the upper surface 61 of the barrel wheel 6.

Axial play of the cover 8 is limited by the lower surface 82 of the cover 8 in an upper abutment with respect to the base plate 9, the lower surface 82 of the cover 8 being limited by the base plate 9 or by the upper surface 93 of the jewel bearing 91 included in the base plate.

In summary, the first variant of fig. 1 is advantageous in that the ratchet is axially free and the flange on the mandrel facilitates assembly. This configuration has the advantage of no restriction on the core diameter.

The second variant of fig. 2 also comprises an axially free ratchet, with a double restriction on the drum. The core diameter is limited by the size of the drive mechanism 42, which is typically a square or the like.

The invention also concerns a timepiece movement 100 comprising at least one bottom plate 9, a bridge 5 and a barrel 1 of the type described. Advantageously, the plate 5 comprises at least one threaded portion 54, which threaded portion 54 is intended to cooperate in abutment with the upper surface 21 of the ratchet 2 with the smallest possible contact surface.

The invention also relates to a watch 200 comprising a movement 100 of the type described.

Claims (9)

1. Timepiece barrel (1) for pivotal assembly between a bottom plate (9) and a bridge (5) and comprising at least one spring (7) housed between a cover (8) and a pivoting barrel (6) and hooked between said barrel (6) and a arbour (3) at the outer and inner ends of said spring, said arbour (3) pivoting integrally with a ratchet (2) about a pivot axis (D), said barrel (1) comprising a single-piece subassembly (10) coaxial with said pivot axis (D) and comprising said arbour (3) and a hub (4) provided with a flange (17) for limiting the axial oscillation of said barrel (6), wherein said flange (17) carries a pivoting drive mechanism (42) for driving the pivoting of said ratchet (2), said ratchet being axially free in the direction of said pivot axis (D), wherein the axial wobble of the barrel wheel (6) is limited by the upper surface (61) of the barrel wheel (6) in an abutting manner with respect to the one-piece subassembly (10), the upper surface (61) of the barrel wheel (6) is limited by the lower shoulder (12) of the one-piece subassembly (10), the axial wobble of the ratchet wheel (2) is limited by the upper surface (21) of the ratchet wheel (2) in an abutting manner with respect to the clamping plate (5), the upper surface (21) of the ratchet wheel (2) is limited by the threaded portion (54) or by the lower surface of the clamping plate (5) or by the lower surface (53) of a jewel bearing (52) comprised in the clamping plate (5), wherein the axial wobble of the ratchet wheel (2) is limited by the lower surface (22) of the ratchet wheel (2) in an abutting manner with respect to the barrel wheel (6), the lower surface (22) of the ratchet wheel (2) is limited by the upper surface (61) of the barrel wheel (6), the axial oscillation of the cover (8) is limited by the lower surface (82) of the cover (8) in an abutment above the base plate (9), the lower surface (82) of the cover (8) is limited by the upper surface of the base plate (9) or the upper surface (93) of a jewel bearing (91) included in the base plate, characterized in that the balance spring is made of a multiphase cobalt nickel chromium based alloy comprising 44% to 46% cobalt, 20% to 22% nickel, 17% to 19% chromium, 4% to 6% iron, 3% to 5% tungsten, 3% to 5% molybdenum, 0 to 2% titanium, 0 to 1% beryllium, and has a young's modulus between 200 and 240GPa and a shear modulus between 80 and 100GPa, wherein the balance spring (7) has a width-to-thickness ratio of between 3 and 23, the ratio of the maximum radius of the bearing shoulder (31) of the balance spring at the arbour (3) to the thickness of the balance spring (7) being between 3 and 9.

2. Barrel (1) according to claim 1, characterized in that said single-piece subassembly (10) pivots on an upper support (13) and comprises an upper shoulder (11) in a hole (51) of said clamping plate (5) or of a jewel bearing (52) comprised in said clamping plate (5), the stroke of the upper shoulder (11) is limited by the lower surface of the clamping plate (5) or the lower surface (53) of the jewel bearing (52), said ratchet (2) being comprised between said upper shoulder (11) and lower shoulder (12), the lower shoulder (12) being included in the one-piece subassembly (10) and located on the hub (4), said lower shoulder (12) limiting the travel of the upper surface (61) of the drum (6), the drum (6) pivots with a cylindrical shoulder (41) of the hub (4) in a hole (62) included in the drum.

3. A barrel (1) according to claim 2, wherein said lower shoulder (12) is formed by a lower abutment surface (16) of said flange (17).

4. A barrel (1) according to claim 3, wherein said flange (17) separates the barrel wheel (6) from the ratchet wheel (2) and comprises an upper abutment surface (15) for abutment of a lower surface (22) of the ratchet wheel (2), wherein said flange carries said pivot drive mechanism (42) beyond said upper abutment surface (15) on a side opposite to said lower abutment surface (16).

5. A barrel (1) according to claim 2, wherein said arbour (3) comprises a shoulder (31) having a smaller diameter than a cylindrical shoulder (41) of said hub (4), said shoulder (31) carrying said spring (7) by: said spring (7) being fixed to said shoulder (31) by friction or welding, or said spring (7) being carried on a hook (32) surrounding said shoulder (31) comprised in said arbour (3), wherein said shoulder (31) pivots in a hole (91) of said sole plate (9) or of a jewel bearing (92) comprised in the sole plate (9).

6. Barrel (1) according to claim 1, characterized in that the barrel wheel (6) carries the cover (8) which pivots integrally with the barrel wheel (6), wherein the hole (81) of the cover (8) cooperates with the shoulder (31) of the arbour (3), the travel of the lower surface (82) of the cover (8) being limited by the upper surface of the bottom plate (9) or by the upper surface (93) of a jewel bearing (92) housed in the bottom plate (9), the hole (91) of the bottom plate (9) or of the jewel bearing (92) acting as a pivot for the shoulder (31) of the arbour (3).

7. Timepiece movement (100) comprising at least one bottom plate (9), a bridge (5) and a barrel (1) according to claim 1.

8. Timepiece movement (100) according to claim 7, wherein the plate (5) comprises at least one threaded portion (54) intended to cooperate in abutment with the upper surface (21) of the ratchet (2) with the smallest possible contact surface.

9. A watch (200) comprising a timepiece movement (100) according to claim 7 or 8.