CLOCK HANDLE

Description

[0001] The present invention relates to a watch hand barrel.

[0002] The barrel of a watch hand is a hollow part or component to which the hand is attached and by means of which the hand is fixed to its shaft. The barrel may be a separate piece or may be a single unit with the hand. It is pressed onto the shaft.

[0003] When a watch needs to be disassembled for maintenance or repair, one of the first steps after opening the watch case is to remove the hands. This can be done by lifting the shank of each hand using levers that rest against the dial. During this operation, the lifting end of the levers acts on the underside of a ring-shaped projection on the shank to separate the shank from the shaft. However, there is a risk that the lifting end may slip past the ring-shaped projection and come into contact with the hand, causing scratches, chips, deformation, etc. The risk of damaging the hand is particularly high if it is made of a fragile material.

[0004] Document JPS63195284U reveals a needle barrel with a lower groove ending in a wedge. 1

[0005] The present invention aims to remedy this drawback or at least mitigate it and proposes for this purpose a barrel according to claim 1, a barrel-needle assembly according to claim 9 and a method of dislodging according to claim 12.

[0006] Other features and advantages of the present invention will become apparent from the following detailed description, made with reference to the accompanying drawings, in which: there figure 1 is a profile view of a barrel-needle assembly according to the invention; the figure 2 is a partial longitudinal cross-sectional view of the barrel-needle assembly of the figure 1 ; there figure 3 A cross-sectional view shows the barrel-needle assembly according to the invention being detached from a shaft on which it was mounted; figure 4 is a detailed cross-sectional view showing in particular the profile (radial section) of a groove made in a projection of the barrel.

[0007] The watch assembly illustrated in figures 1 et 2 consists of a barrel 10 and a hand 11 fixed to the barrel 10. The hand 11 can be an indicator hand for hours, minutes, date, etc. It comprises a head 12 and a body 13. The barrel 10 is intended to be driven onto the drive shaft 14 of the hand 11.

[0008] The barrel 10 has an axis of revolution A and comprises, around this axis A, a generally cylindrical wall 15 and a projection 16 protruding from the outside of the wall 15. The upper surface 17 of the projection 16 forms, with an upper portion 18 of the wall 15, a shoulder that receives the head 12 of the needle 11. The head 12 is fixed to the upper surface 17 of the projection 16 by gluing or brazing, for example. A lower portion 19 of the wall 15 may be slightly frustoconical, as shown, to facilitate mounting the barrel 10 on the shaft 14.

[0009] Typically, the barrel 10 is made of metal or alloy, and the hand 11 is made of a fragile material such as silicon, glass, or sapphire—that is, a material that does not have a plastic deformation range at room temperature (25°C). In the case of a transparent material such as glass, sapphire, or similar, the hand 11 is colored, at least at its free end, for example, by means of paint, to ensure its display function. The metal or alloy constituting the barrel 10 may be, in particular, brass, possibly coated with a protective or decorative layer such as a layer of gold.

[0010] The lower surface 20 of the projection 16 is the surface through which the watchmaker can act, when he wishes to access the inside of the watch movement, to detach the hand 11 from the shaft 14 and remove it. In the present invention, this lower surface 20, of annular shape, has a groove 21 with which the lifting end 22 of levers 23 can cooperate (cf. figure 3 ). These levers 23 can be placed against the dial 24 of the watch, preferably previously protected, with their lifting end 22 against the bottom of the groove 21, and can be operated manually to lift the barrel 10 relative to the shaft 14. Thanks to the groove 21, the lifting end 22 is prevented from sliding beyond the projection 16 and from striking the head 12 of the hand 11, which protrudes from the projection 16, or even the body 13 of the hand 11.

[0011] As shown by figure 4, the profile of the throat 21 defines a wedge 25 in which the lifting end 22 can lock after the barrel 10 has been raised to a certain height.

[0012] Advantageously, the profile of the groove 21 is asymmetrical, without a corner on the part 26 of the groove 21 opposite the corner 25, in order to facilitate the manufacture of the barrel 10, in particular if it is made by turning.

[0013] The width L1 of the groove 21 is preferably at least 40% or even at least 50% or even at least 60% of the width L2 of the projection 16, and is preferably at least 150 µm, or even at least 170 µm, or even at least 190 µm.

[0014] The depth P of the groove 21 is preferably at least 10%, or even at least 15%, or even at least 20%, or even at least 25% of the thickness E of the projection 16, and is preferably at least 15 µm, or even at least 25 µm, or even at least 35 µm, or even at least 45 µm, or even at least 55 µm.

[0015] Instead of being cut into the projection 16, as shown in the figures, the groove 21 could be created by adding a bead (for example deposited, glued, brazed or welded) on the lower surface 20 of the projection 16 or by mounting a ring (for example pressed, glued, brazed or welded) on the edge of the projection 16.

[0016] The invention also applies to barrels that are one piece with their needle and to metallic needles.

Claims

1. Pipe (10) for a timepiece hand and intended to be driven onto an arbor (14), the pipe (10) having an axis of revolution (A) and comprising, around the axis (A), a cylindrical wall (15) and a protrusion (16) forming a relief on the outside of the wall (15), an inner surface (20) of the protrusion (16) which has an annular shape (20) and on which the lifting end (22) of at least one lever (23) can act to drive out the pipe (10), having a groove (21) able to cooperate with the lifting end (22), the profile of the groove (21) having a corner (25), the corner (25) being able to retain the lifting end (22) as the pipe (10) is driven out after the lifting end (22) has raised the pipe (10) by a certain height, the pipe being characterised in that the profile of the groove (21) is configured to allow the lifting end (22) to slide along the profile of the groove (21) before being locked in the corner (25).

2. Pipe (10) as claimed in claim 1, characterised in that the upper surface (17) of the protrusion (16) is intended to be used as an abutment against a head (12) of the hand (11).

3. Pipe (10) as claimed in claim 2, characterised in that the width (L1) of the groove (21) is at least 40%, preferably at least 50%, preferably at least 60%, of the width (L2) of the protrusion (16).

4. Pipe (10) as claimed in claim 2 or 3, characterised in that the depth (P) of the groove (21) is at least 10%, preferably at least 15%, preferably at least 20%, preferably at least 25% of the thickness (E) of the protrusion (16).

5. Pipe (10) as claimed in any one of claims 1 to 4, characterised in that the width (L1) of the groove (21) is at least 150 µm, preferably at least 170 µm, preferably at least 190 µm.

6. Pipe (10) as claimed in any one of claims 1 to 5, characterised in that the depth (P) of the groove (21) is at least 15 µm, preferably at least 25 µm, preferably at least 35 µm, preferably at least 45 µm, preferably at least 55 µm.

7. Pipe (10) as claimed in any one of claims 1 to 6, characterised in that the profile of the groove (21) is asymmetrical.

8. Pipe (10) as claimed in any one of claims 1 to 7, characterised in that it is made of metal or an alloy.

9. Timepiece assembly comprising a pipe (10) as claimed in any one of claims 1 to 8 and a hand (11) fixed to the pipe (10).

10. Timepiece assembly as claimed in claim 9, characterised in that the hand (11) is made of a fragile material.

11. Timepiece assembly as claimed in claim 9 or 10, characterised in that the hand (11) is fixed to the pipe (10) by gluing or brazing.

12. Method for driving out a pipe (10) for a timepiece hand as claimed in any one of claims 1 to 8, characterised in that the pipe (10) is raised with respect to the arbor (14) onto which it was driven using at least one lever (23), the lifting end (22) of which cooperates with the groove (21).