HK1199115B - Timepiece barrel - Google Patents

Description

Barrel for a timepiece

Technical Field

The invention relates to a timepiece barrel for pivotal assembly between a bottom plate and a bridge and including at least one spring which is interposed between a cover and a pivotal barrel and is hooked between said barrel and a arbour at its outer end and at its inner end, said arbour pivoting integrally with a ratchet about a pivot axis, said barrel including a single-piece subassembly coaxial with and carrying said ratchet and including, on either side of said ratchet, a hub for pivotally guiding said barrel in said bottom plate, said hub forming one end of said arbour.

The invention also concerns a timepiece movement including 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, while the ratchet is usually fixed by means of 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 clearance of the core or spindle relative to the baseplate or bridge carrying the jewel 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.

US patent No.1561673A to Ulery, published in 1925, discloses a barrel with a mandrel comprising a collar acting as a geared support for driving a barrel wheel. The spindle comprises at its opposite ends two housings, one of which receives a pin for guiding the spindle in a bearing housed in the bottom plate and for holding the end of said spindle in said bearing, the other housing receives a pinned conical bolt having a similar shoulder for upper guiding in the bridge and a ratchet drive square at its distal end.

CH patent No.15286A to Danasino, published in 1898, discloses a barrel with a smooth arbor carrying a hollow fusee comprising a ratchet. The hollow fusee has two shoulders for receiving the barrel wheel and the cover. The section of the mainspring becomes gradually larger from the outer end toward the inner end thereof.

US patent No.168581A to Potter, published 1875, discloses a barrel with a substantially smooth mandrel which pivots at both ends between two plates located on either side of a bottom plate in which the barrel is embedded and which forms a cover for the barrel wheel. The mandrel carries a hollow fusee which carries a wheel and to which the inner end of the spring is hooked. On the abutting part of the uniform force conical wheel, the mandrel bears the barrel wheel, and the outer end of the clockwork spring is hooked on the barrel wheel. The mandrel then carries a ratchet wheel which rests on a small step of the mandrel and is constrained under one of the cross plates.

Disclosure of Invention

The present 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 preferably more economical costs than the known barrels.

The invention therefore concerns a barrel for a timepiece, intended to be pivotally assembled between a bottom plate and a bridge and comprising at least one spring, the spring being arranged between the ratchet and the pivoting drum and being hooked between said drum and a arbour at its outer end and at its inner end, said arbour pivoting integrally with said ratchet about a pivot axis, characterized in that said barrel comprises a one-piece subassembly coaxial with said arbour and combining said arbour and said ratchet immediately adjacent to said base plate around a hub, said barrel comprising a single-piece subassembly coaxial with said arbour and carrying said ratchet and comprising, on either side of said ratchet, a hub for pivotally guiding said barrel in said bottom plate, said hub forming one end of said arbour, characterized in that said ratchet forms a closing cover of said drum and is placed between said drum and said bottom plate; the one-piece subassembly pivots at an upper shoulder in a hole included in the barrel wheel on an end tube, the outer shoulder of which pivots in a hole of the bridge or a gemstone included in the bridge.

According to a feature of the invention, said barrel wheel has an upper surface, the travel of which is limited by the lower surface of said bridge or of a jewel included in said bridge; the barrel wheel pivots in a hole included in the barrel wheel at an upper shoulder of the spindle of the single-piece subassembly; the ratchet is located between a lower end surface of the barrel wheel, which is located on the opposite side of the upper surface with respect to the spring confined within the barrel wheel, and a lower step on the hub included in the single-piece subassembly, which limits the travel of the single-piece subassembly relative to the sole plate or a gemstone included in the sole plate, the lower shoulder of the single-piece subassembly being pivoted in the bore.

According to another feature of the invention, the one-piece subassembly pivots at an upper shoulder in a hole in the bridge or a jewel included in the bridge.

According to another feature of the invention, the one-piece subassembly comprises a receiving shoulder on the arbour for receiving the spring, the receiving shoulder having a diameter greater than the diameter of the upper shoulder, the upper shoulder extending the receiving shoulder on the side opposite the ratchet; said arbour comprises, between said receiving shoulder and said upper shoulder, a step arranged to cooperate in abutment with an inner surface of said drum, close to an upper surface of said drum, on the opposite side of the same flange of said drum, the travel of said upper surface being limited by the lower surface of said bridge or of a jewel comprised in said bridge.

According to another characteristic of the invention, the arbour comprises a shoulder of diameter less than that of the hub, which carries the spring by: the spring is friction fitted or welded to the shoulder or carried on a hook included in the mandrel around the shoulder; the hub includes a shoulder near the ratchet that pivots in the base plate or a hole of a gemstone included in the base plate.

According to a further feature of the invention, the drum axial play (shake) is limited with respect to the bridge plate by an upper surface of the drum in a lower abutment (in lower abutment) limited by the bridge plate or by a lower surface of a gemstone included in the bridge plate; the axial clearance of the drum is limited in an abutting manner with respect to the ratchet by a lower end surface of the drum, which is located on the opposite side of the upper surface with respect to the spring confined within the drum, being limited by an upper surface of the ratchet of the one-piece subassembly; the axial clearance of the ratchet is limited in an abutting manner with respect to the base plate by a lower surface of the one-piece subassembly, which is limited by the base plate or an upper surface of a gemstone included in the base plate.

According to a further feature of the present invention, the balance spring is made of a multiphase cobalt-nickel-chromium based alloy comprising 44-46% cobalt, 20-22% nickel, 17-19% chromium, 4-6% iron, 3-5% tungsten, 3-5% molybdenum, 0-2% titanium, 0-1% beryllium and having a Young's modulus between 200GPa and 240GPa and a shear modulus between 80GPa and 100 GPa; said balance spring having a width to thickness ratio of between 3 and 23; the ratio between the maximum radius of the spring receiving shoulder of the arbour and the thickness of the spring is between 3 and 9.

The invention also concerns a timepiece movement including 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 upon reading the following detailed description and upon reference to the drawings in which:

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

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

Fig. 3 shows a block diagram of a timepiece including a movement having a barrel according to the invention.

Detailed Description

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

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

Barrel 1 comprises a single-piece subassembly 10 coaxial with said arbour 3 and combining at least ratchet 2 and arbour 3 together around hub 4. This single-piece subassembly 10 carries the ratchet 2 and comprises, on both sides of the ratchet 2, said hubs 4 which pivotally guide the barrel 1 in the bottom plate 9. The hub 4 forms one end of the spindle 3.

According to the invention, ratchet 2 forms a closure for drum 6 and is placed between drum 6 and bottom plate 9; ratchet 2 is in close proximity to bottom plate 9 and closes the chamber defined by barrel 6 around spring 7.

The single-piece subassembly 10 pivots at the upper shoulder 13 in a hole 51 in the bridge 5 or a jewel 52 included in the bridge 5.

In the first variant of fig. 1, the single subassembly 10 has no upper step.

In a second variant of fig. 2, the single-piece subassembly 10 has an upper step 15, the travel of the upper step 15 being limited by the bottom surface 65 of the drum 6.

Ratchet 2 is located between shoulder 31 of arbour 3 on the one hand and lower step 22 on hub 4 comprised in single-piece subassembly 10 on the other hand, wherein spring 7 is fixed to arbour 3 at shoulder 31. The lower step 22 limits the travel of the one-piece subassembly 10 by abutting against the bottom plate 9 or the upper surface 93 of a jewel 92 included in the bottom plate 9.

Barrel wheel 6 has an upper surface 61, the travel of which (61) is limited by bridge 5 or by lower surface 53 of jewel 52 included in bridge 5.

Drum 6 pivots in hole 62 included in drum 6 at upper shoulder 13 of mandrel 3 of single-piece subassembly 10.

The ratchet 2 is arranged between, on the one hand, a lower end surface 63 of the drum 6, said lower end surface 63 being located on the opposite side of said upper surface 61 with respect to the spring 7 constrained within said drum 6, and, on the other hand, said lower step 22 on the hub 4 comprised in the single-piece sub-assembly 10.

The base plate 9 or a jewel 92 included in the base plate 9 includes a hole 91 in which the lower shoulder 41 of the one-piece subassembly 10 pivots.

In the second variant of fig. 2, single-piece subassembly 10 is pivoted at upper shoulder 13 on an end tube in hole 62 comprised in drum 6, whose outer shoulder 64 is pivoted in hole 51 of bridge 5 or of jewel 52 comprised in bridge 5.

In a second variant, shown in fig. 2, single-piece subassembly 10 comprises a receiving shoulder 31 on arbour 3 for receiving spring 7, said receiving shoulder 31 having a diameter greater than the diameter of upper shoulder 13, said upper shoulder 13 extending said receiving shoulder 31 on the side opposite ratchet 2. The mandrel 3 comprises, between the receiving shoulder 31 and the upper shoulder 13, a step 15, which step 15 is arranged to cooperate against the inner surface 65 of the drum 6. This inner surface 65 is close to the upper surface 61 on the opposite side of the same flange of drum 6, the travel of the upper surface 61 being limited by bridge 5 or by the lower surface 53 of jewel 52 comprised in bridge 5.

Mandrel 3 has a shoulder 31 of diameter preferably smaller than the diameter of hub 4 at lower shoulder 41 of single-piece subassembly 10, this shoulder 31 carrying spring 7 by: spring 7 is friction fitted or welded to said shoulder 31, or spring 7 is carried on a hook 32 surrounding shoulder 31 included in arbour 3.

The hub 4 comprises, close to the ratchet 2, a shoulder 41, which shoulder 41 pivots in a hole 91 in the bottom plate 9 or in a jewel 92 comprised in the bottom plate 9.

The axial clearance of barrel wheel 6 is limited in an upper abutment with respect to bridge 5 by an upper surface 61 of barrel wheel 6, which upper surface 61 is limited by bridge 5 or by a lower surface 53 of jewel 52 comprised in bridge 5.

The axial play of drum 6 is limited in an abutting manner with respect to ratchet 2 by a lower end surface 63 of drum 6, lower end surface 63 being on the opposite side of upper surface 61 with respect to spring 7 constrained within drum 6. The lower end surface 63 is bounded by the upper surface 21 of the ratchet 2 of the one-piece subassembly 10.

The axial clearance of the ratchet 2 is limited in an abutting manner with respect to the bottom plate 9 by a lower step 22 of the one-piece subassembly 10, which lower step 22 is limited by the bottom plate 9 or by an upper surface 93 of a jewel 92 comprised in the bottom plate 9.

In short, the first variant of fig. 1 is advantageous because the one-piece subassembly 10 combines the functions of cover, ratchet, arbour and hub, without the complexity of machining, except for the hook 32 of the spring 7. There are three axial clearance corrections. The upper surface 21 of the ratchet 2, intended to cooperate with the lower surface 63 of the barrel wheel 6, may advantageously have a teflon profile,Or similar coating, to reduce the friction torque between drum 6 and ratchet 2. The advantages of this structure are: there is no limitation on the diameter of the hub. In a second variant, shown in fig. 2, the diameter of the hub is limited by the diameter of the pivot shoulder in the bridge 5.

The mainspring can be made of various materials: carbon steel, stainless steel,Silicon, diamond-like, quartz, glass, or similar materials. In a particular application, the balance spring 7 is made of a multiphase cobalt-nickel-chromium based alloy comprising 44-46% cobalt, 20-22% nickel, 17-19% chromium, 4-6% iron, 3-5% tungsten, 3-5% molybdenum, 0-2% titanium and 0-1% beryllium and having a Young's modulus between 200GPa and 240GPa and a shear modulus between 80GPa and 100 GPa. Said balance spring 7 preferably has a width-to-thickness ratio comprised between 3 and 23, and more preferably between 9 and 21.

Also, the maximum radius of the shoulder 31 of the arbour 3 with respect to the pivot axis D (without taking into account any excess thickness of the hook 32) made of steel or stainless steel, for example 4C27A hardenable steel (also known according to different standards as 1.4197, ASTM420F or DIN X22CRMoNiS 131) is less than 9 times the maximum thickness of the balance spring 7. In particular, for the embodiment shown, it is possible to obtain a ratio of the maximum radius of shoulder 31 of arbour 3 to the thickness of balance spring 7 of between 3 and 9, preferably between 4 and 6, preferably close to 5.

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 above.

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

Claims (8)

1. A barrel (1) for a timepiece, the barrel (1) being intended to be pivotally assembled between a bottom plate (9) and a bridge (5) and comprising at least one spring (7), the spring (7) being interposed between a ratchet (2) and a pivoting barrel wheel (6) and being hooked between the barrel wheel (6) and a arbour (3) at its outer end and at its inner end, the arbour (3) pivoting integrally with the ratchet (2) about a pivot axis (D), the barrel (1) comprising a single-piece subassembly (10), the single-piece subassembly (10) being coaxial with the arbour (3) and carrying the ratchet (2) and comprising, on either side of the ratchet (2), a hub (4) for pivotally guiding the barrel (1) in the bottom plate (9), the hub (4) forming one end of the arbour (3), characterized in that said single-piece subassembly (10) comprises a lower shoulder (41) surrounding said hub (4) arranged to pivot in said bottom plate (9), said arbour (3) extending to one side of said bridge (5), and said ratchet (2) being arranged in front of said bottom plate (9), wherein said ratchet (2) forms a closing cover of said barrel wheel (6) and is placed between said barrel wheel (6) and said bottom plate (9); the single-piece subassembly (10) pivots on an end tube in a hole (62) included in the barrel wheel (6) at an upper shoulder (13), the outer shoulder (64) of the end tube pivoting in a hole (51) of the bridge plate (5) or a jewel (52) included in the bridge plate (5).

2. Barrel (1) for a timepiece according to claim 1, wherein said barrel wheel (6) has an upper surface (61), the travel of which upper surface (61) is limited by a lower surface (53) of said bridge (5) or of a jewel (52) included in said bridge (5); the barrel wheel (6) is pivoted in a hole (62) comprised in the barrel wheel (6) at an upper shoulder (13) of the mandrel (3); the ratchet wheel (2) is located between a lower end surface (63) of the drum (6) and a lower step (22) comprised on the hub (4), the lower end surface (63) of the drum (6) being located on the opposite side of the upper surface (61) with respect to the spring (7) confined within the drum (6), the lower step (22) limiting the travel of the one-piece subassembly (10) with respect to the sole plate (9) or a jewel (92) comprised in the sole plate (9) at a hole (91) of the sole plate (9) or of the jewel (92) comprised in the sole plate (9), the lower shoulder (41) pivoting in the hole (91).

3. Barrel (1) for a timepiece according to claim 1, wherein said single-piece subassembly (10) comprises a spring receiving shoulder (31) on said arbour (3) for receiving said spring (7), said spring receiving shoulder (31) having a diameter greater than the diameter of said upper shoulder (13), said upper shoulder (13) extending said spring receiving shoulder (31) on the opposite side to said ratchet (2); said mandrel (3) comprising, between said receiving shoulder (31) and said upper shoulder (13), a step (15), said step (15) being arranged in abutting cooperation with an inner surface (65) of said barrel wheel (6), said inner surface (65) being close to an upper surface (61) of said barrel wheel (6) on the opposite side of the same flange of said barrel wheel (6), the travel of said upper surface (61) being limited by a lower surface (53) of said bridge plate (5) or of a jewel (52) comprised in said bridge plate (5).

4. Barrel (1) for a timepiece according to claim 1, wherein said lower shoulder (41) pivots in a hole (91) of said bottom plate (9) or in a hole (91) of a jewel (92) included in said bottom plate (9), said arbour (3) comprising a spring receiving shoulder (31) of smaller diameter than the diameter at said lower shoulder (41), this spring receiving shoulder (31) carrying said spring (7) by: the spring (7) is friction-fitted or welded to the spring receiving shoulder (31), or the spring (7) is carried on a hook (32) included in the arbour (3) around the spring receiving shoulder (31).

5. Barrel (1) for a timepiece according to claim 1, wherein the axial clearance of the barrel wheel (6) is limited by an upper surface (61) of the barrel wheel (6) in a below abutment with respect to the bridge (5), said upper surface (61) being limited by the bridge (5) or by a lower surface (53) of a jewel (52) comprised in the bridge (5); the axial clearance of the drum (6) is limited in an abutting manner with respect to the ratchet (2) by a lower end surface (63) of the drum (6), said lower end surface (63) being located on the opposite side of the upper surface (61) with respect to the spring (7) confined within the drum (6), said lower end surface (63) being limited by the upper surface (21) of the ratchet (2) of the one-piece subassembly (10); the axial clearance of the ratchet (2) is limited in an abutting manner with respect to the base plate (9) by a lower step (22) of the single-piece subassembly (10), the lower step (22) being limited by the base plate (9) or by an upper surface (93) of a jewel (92) comprised in the base plate (9).

6. Barrel (1) for a timepiece according to claim 1, wherein the spring (7) is made of a multiphase cobalt-nickel-chromium based alloy comprising 44-46% cobalt, 20-22% nickel, 17-19% chromium, 4-6% iron, 3-5% tungsten, 3-5% molybdenum, 0-2% titanium, 0-1% beryllium and has a young's modulus between 200GPa and 240GPa and a shear modulus between 80GPa and 100 GPa; said balance spring (7) having a width to thickness ratio between 3 and 23; the ratio between the maximum radius of the spring receiving shoulder (31) of the arbour (3) and the thickness of the spring (7) is between 3 and 9.

7. Timepiece movement (100), characterized in that the timepiece movement (100) comprises at least one bottom plate (9), a bridge (5) and a barrel (1) for a timepiece according to claim 1.

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