Timepiece barrel with a twisted arbour

Abstract

A twisted arbour barrel (1), including a barrel drum (2) provided with a housing, a spring arranged in the housing of the barrel drum (2), an arbour (4) at least partially passing through the housing, the spring being compressed by rotation of the arbour in a first direction of rotation (12), the arbour (4) being provided with a protruding end (9) of the drum (2), a ratchet (3) arranged on the drum (2), the ratchet (3) being configured to allow the rotation of the arbour (4) in the first direction of rotation (12), the protruding end (9) passing through the ratchet (3) through an opening (14) cooperating by interlocking with the protruding end (9), the protruding end (9) of the arbour (4) having a twisted shape around its axis.

Claims

1. A twisted arbour barrel comprising: a barrel drum provided with a housing, a spring arranged in the housing of the barrel drum, an arbour at least partially passing through the housing, said spring being compressed by rotation of said arbour in a first direction of rotation, the arbour being provided with a protruding end, a ratchet arranged on the drum, the ratchet being configured to allow the rotation of the arbour in the first direction of rotation, the protruding end passing through the ratchet through an opening cooperating by interlocking with the protruding end, wherein said protruding end has a shape twisted around its axis.

2. The barrel according to claim 1, wherein the protruding end is twisted in the direction opposite to said first direction relative to the drum.

3. The barrel according to claim 1, wherein said protruding end is of polygonal section, the opening of the ratchet having a corresponding shape.

4. The barrel according to claim 3, wherein said protruding end is of square section.

5. The barrel according to claim 1, wherein edges of said protruding end are chamfered.

6. The barrel according to claim 1, wherein said protruding end comprises a distal face angularly offset relative to its base on the barrel.

7. The barrel according to claim 6, wherein the offset is at least 30 degrees.

8. The barrel according to claim 1, further comprising a core surrounding said arbour, the core being arranged in the housing.

9. The barrel according to claim 8, wherein the spring is held in the housing, on the one hand, at an internal peripheral face of the barrel, and on the other hand, at the core.

10. The barrel according to claim 1, wherein the arbour passes through the housing and is mounted rotationally free relative to said barrel drum.

11. The barrel according to claim 1, further comprising a pawl cooperating directly or indirectly with teeth arranged on an outer peripheral face of the drum, so as to prevent the drum from rotating in the direction opposite to the first direction.

12. A horological movement comprising the barrel according to claim 1.

13. A timepiece comprising the horological movement according to claim 12.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention will be described in more detail below using the appended drawings, given by way of non-limiting examples, wherein:

(2) FIG. 1 schematically shows a perspective view of a barrel according to one embodiment of the invention, the ratchet being in a first position;

(3) FIG. 2 schematically shows a perspective view of a barrel according to one embodiment of the invention, the ratchet being in a second position; and

(4) FIG. 3 schematically shows a perspective view of an arbour of a barrel according to one embodiment of the invention;

(5) FIG. 4 schematically shows a sectional view of part of an automatic winding horological movement provided with a barrel according to the invention;

(6) FIG. 5 shows schematically a perspective view of part of a manual winding horological movement provided with a barrel according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(7) The present invention relates to a barrel 1 with a twisted arbour 4, as shown in FIGS. 1 and 2.

(8) The barrel 1 comprises a cylindrical-shaped barrel drum 2. The drum 2 comprises an upper face 5 and a lower face 8 in the shape of discs, as well as a rounded peripheral face 6. The drum 2 is provided with a housing delimited by the upper 5, lower 8 and peripheral 6 faces.

(9) The peripheral face 6 of the drum 2 is provided with gear teeth 7 at the junction of the upper face 5. These teeth 7 allow the torque of the spring to be transmitted to the rest of the movement, in particular to actuate the movement of the hands.

(10) The barrel 1 includes an arbour 4 passing through the housing. The arbour 4 extends around a main longitudinal axis about which it can rotate. The arbour 4 is provided with a protruding end 9 of said drum 2.

(11) The barrel 1 comprises a spring, not shown in the figures, the spring being arranged in the housing of the barrel drum 2. The spring is spiral shaped. The spring is held in the housing, on the one hand, at the internal peripheral face 6 of the barrel, and on the other hand, at the arbour 4. The spring is compressed by rotation of said arbour 4 in a first direction of rotation 12.

(12) The barrel 1 is provided with a ratchet 3 arranged on the drum 2. In the operating position, as shown in FIG. 2, the ratchet 3 rests on the upper face 5 of the barrel drum 2. The major part of the protruding end 9 projects beyond the ratchet 3. The ratchet 3 is a flat disc provided with peripheral gear teeth 13. The ratchet 3 is configured to allow the rotation of the arbour 4 in the first direction of rotation 12. The ratchet 3 comprises an opening 14 cooperating by interlocking with the protruding end 9 of the arbour 4, the protruding end 9 passing through the ratchet 3. In one movement, the ratchet 3 is for example blocked in the other direction by a pawl, not shown in the figures. The pawl does not prevent the ratchet from rotating in the first direction 12. Thus, when the ratchet 3 is rotated, the arbour 4 rotates in the first direction 12 and compresses the spiral spring inside the drum housing 3. But the ratchet 3 is blocked in the other direction so that the spring remains compressed. Thus, the force exerted by the spring rotates the barrel 2 to actuate the mechanism of the horological movement, and not the arbour 4.

(13) According to the invention, said protruding end 9 of the arbour 4 has a shape twisted around its axis. The protruding end 9 is twisted in the direction opposite to said first direction 12 relative to the drum 2. Said protruding end 9 is of polygonal section, the opening 14 of the ratchet 3 having a corresponding shape. Said protruding end 9 is of square section in the figures. Preferably, the edges of said protruding end 9 are chamfered. Said protruding end 9 comprises a distal face 16 angularly offset relative to its base at the height of the barrel 1. The offset is preferably at least 30 degrees, or even 45 degrees.

(14) To remove the ratchet 3, for example during maintenance of the movement, the ratchet 3 is wound along the protruding end 9 by rotating it by an angle corresponding to that of the twist of the arbour 4. For this purpose, the ratchet 3 rotates in the direction 15 of the twist of the protruding end 9. Thus, the position of the opening 14 always corresponds to the shape of the section of the protruding end 9, the ratchet 3 being able to slide along the protruding end 9.

(15) FIG. 3 shows the arbour 4 provided with the protruding end 9 and the upper face 16. The arbour 4 further comprises a core 11 surrounding said arbour, the core 11 being arranged in the housing. The spring is held at the core 11 of the arbour 4.

(16) Thus, in the barrel 1, the spring applies a force to the arbour 4 through the core 11, the arbour 4 transmitting the force to the ratchet 3, which is blocked by the pawl. Thus, the ratchet 3 does not risk sliding along the protruding end, because the force is applied in the direction 12 opposite to the direction 15 of the twist.

(17) The present invention also relates to a horological movement 10 comprising a barrel as described above.

(18) FIG. 4 shows a part 10 of an automatic winding movement comprising the barrel 1 according to the invention. This part 10 comprises a plate 17 of the movement, an oscillating mass 18, a barrel bridge 19, a bridge 21 of the automatic winding system, gears 22 of the hand display system of the timepiece. The plate 17 and the two bridges 19, 21 are substantially parallel. From bottom to top, there is the plate 17, the barrel bridge 19, the bridge 21 of the automatic winding system and the oscillating mass 18. The gears 22 are disposed next to the barrel bridge 19, under the bridge 21 of the automatic winding system.

(19) The barrel 1 is mounted between the plate 17 and the barrel bridge 19. To this end, the protruding end 9 of the arbour 4 passes through the barrel bridge 19 and the ratchet 3, the ratchet 3 being arranged on the barrel bridge 19, below the bridge of the automatic winding system 21. The other free end 23 of the arbour is assembled to the plate 17 while being rotationally free about its axis relative to the latter.

(20) In the manual winding movement of FIG. 5, the movement 20 is similar, but does not have an automatic winding system. The ratchet 3 is engaged with a crown wheel 25, which can be actuated from the outer crown of the timepiece, the crown not being shown in the figures. Thus, by actuating the crown, the crown wheel 25 meshes with the ratchet 3, which rotates the arbour of the barrel 4 to constrain the spring inside the drum 2, and to wind the spring. In this embodiment, the ratchet blocking pawl 26 is arranged on the crown wheel 25 instead of the ratchet 3 directly. The pawl 26 allows the crown wheel 25 to be rotated in one direction only, the direction allowing the spring to be wound.

(21) The invention also relates to a timepiece, not shown in the figures, comprising such a horological movement.