System for attaching display elements

Abstract

One aspect of the invention relates to a system (1) for attaching a display element (2) to a drive shaft (3) fitted to an analog display mechanism of a measuring device, the system (1) comprising a portion (6) for mounting the display element (2), the portion being made of a material having softening properties, and an embeddable end piece (4a) of the drive shaft (3), and an embeddable end piece (4a) configured to be bonded by fusion into the portion (6), the end piece (4a) comprising a portion of the outer peripheral wall (13) of the drive shaft (3) provided with a patterned outer bonding surface configured to mechanically anchor the end piece (4a) in the portion (6).

Description

Technical Field

[0001] The invention relates to the field of measuring instruments, in particular watchmaking, and more particularly to the field of systems for attaching a display element, such as a display hand, to a drive shaft of a display mechanism.

[0002] The invention also relates to a measuring instrument, such as a timepiece, comprising such a display element mounted on the drive shaft using the attachment system. Background Art

[0003] In the prior art, a measuring instrument such as a timepiece comprises a hand attached to its drive shaft by means of a forced-driven attachment system, namely a hollow cylinder, in this case a tube, which is forced onto a spindle whose diameter is slightly greater than the internal diameter of the cylinder. In this system, the elastic and plastic properties of the material used, which is generally a metal, are used for this driving operation. As a result, the hollow cylinder can only be driven onto conventional rotating shafts, such as those used in mechanical watchmaking, whose diameters differ by a few micrometers. Alternatively, the hollow cylinder, which is preferably a straight circular cylinder, can also be driven onto a frustoconical rotating shaft in order to limit excessive driving forces that could damage the movement during this operation.

[0004] Furthermore, the attachment of the hands must provide sufficient force to hold the hands in place during impacts. For example, the force required to actuate a conventional watch hand is of the order of 30N.

[0005] To solve these problems, one solution is to make the pointer with a tube having one or more slots parallel to the axis of rotation and open at the opposite end of the pointer so that the tube deforms elastically.

[0006] However, a major drawback of this solution is that the slots in the tube weaken the tube, which means that the slots must be very narrow in order not to weaken the tube too much. It should also be noted that in order to obtain the finest possible slots while taking into account the width and length required to obtain the desired driving force, the machining operations are complicated, which increases production costs and time. Summary of the invention

[0007] The main purpose of the present invention is to overcome the various disadvantages of the prior art.

[0008] Another object of the invention is to provide an attachment system which improves the holding of a display element having a non-metallic body on a drive shaft of a display mechanism of a measuring instrument and which is therefore insensitive to magnetic fields.

[0009] Another object of the present invention is to provide an attachment system in which the display element has reduced mass and inertia and takes any desired shape.

[0010] Another object of the invention is to provide an attachment system in which the display element is robust over time and whose manufacturing costs are reduced.

[0011] According to the present invention, one aspect of the present invention relates to a system for attaching a display element to a drive shaft, wherein the drive shaft is assembled to an analog display mechanism of a measuring instrument, the system comprising a portion for mounting a display element made of a material having softening properties and an embeddable end piece of the drive shaft, the embeddable end piece being configured to be bonded to the portion by fusion, the end piece comprising a portion of an outer peripheral wall of the drive shaft, the portion being provided with a patterned outer bonding surface, the patterned outer bonding surface being configured to mechanically anchor the end piece in the portion.

[0012] In other embodiments:

[0013] - the mounting portion comprises a tube in which an axial hole is formed, and the axial hole is configured to mount the display element to the drive shaft;

[0014] - Integrating the embeddable end piece into the tube by fusion;

[0015] - the patterned outer surface comprises a plurality of raised patterns;

[0016] - said plurality of raised patterns extend over all or part of said patterned outer surface;

[0017] - a portion of the peripheral wall of the end piece protrudes on both sides of the opposite surface of the mounting portion of the display element;

[0018] - the easily softenable material consists entirely or partly of a plastic material having softening properties;

[0019] - the end piece comprises a first and a second portion protruding respectively from two opposite openings of the axial hole of the tube;

[0020] - the embeddable end piece is made of a material having a softening point higher than the softening point of the material constituting the mounting portion;

[0021] - a region for assembling the mounting portion with the end piece, wherein the materials constituting the end piece and the tube, respectively, are bonded to one another by fusion, integration or association, in particular by using ultrasound;

[0022] - the display element has a body that is symmetrical with respect to a longitudinal plane of symmetry and / or a transverse plane of symmetry;

[0023] - The display element is a display pointer, the body of which comprises a plate provided with the assembly area.

[0024] Another aspect of the invention relates to a measuring instrument comprising at least one such display element mounted on an embeddable end piece of a drive shaft using such an attachment system.

[0025] Advantageously, such an instrument is a timepiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Other characteristics and advantages of the invention will be better understood by reading the following description given by way of a non-limiting specific embodiment of the invention, said description being provided for descriptive purposes with reference to the accompanying drawings, in which:

[0027] Figure 1 is a view of a system for attaching a display element for mounting the element on an embeddable end piece of a drive shaft assembled to a display mechanism of a measuring instrument according to one embodiment of the present invention;

[0028] Figure 2 is a top view of an attachment system according to an embodiment of the present invention, wherein the end piece of the shaft is incorporated into or integrated into or combined with the tube of the display element; and

[0029] Figure 3 According to an embodiment of the present invention Figure 2 A longitudinal cross-sectional view along line III-III of the mounting portion of the display element is shown. DETAILED DESCRIPTION

[0030] refer to Figures 1 to 3 The present invention relates to a system 1 for attaching a display element 2 to a drive shaft 3 of an analog display mechanism of a mechanical, electronic or hybrid measuring instrument. The device can help to measure the speed of movement of an object by acting as a tachometer, by acting as a barometer to measure atmospheric pressure or even by acting as a timepiece such as a watch in a non-limiting and non-exhaustive manner. It should be noted that such a measuring instrument can be a portable object.

[0031] refer to Figure 1 , the system 1 comprises a display element 2 and in particular a mounting portion 6 of the element 2 and a drive shaft 3 and in particular an end piece 4a of the shaft 3. In the system 1, the end piece 4a and the portion 6 are configured to cooperate with each other so as to attach the display element 2 to the drive shaft 3. More specifically, the portion 6 comprises a tube 14 in which a shaft hole 5 is provided, which hole is configured to mount the display element 2 on the drive shaft 3. In other words, the tube 14 and the end piece 4a are configured to cooperate with each other so as to attach the display element 2 to the drive shaft 3.

[0032] Such a display element 2, also called a "display indicator", comprises a body 8 provided with a mounting portion 6, the mounting portion comprising an assembly area 7, the assembly area comprising a tube 14, in or with which a drive shaft 3 of a drive member of a display mechanism can be incorporated, integrated or combined. It should be noted that the invention is applicable to analog display mechanisms for mechanical, electronic or hybrid timepieces.

[0033] In the embodiment of the attachment system 1, the display element 2 is preferably a display pointer 2. However, it is clearly understood that the display element 2 is obviously not limited to the pointer 2, and it can be completely different from the pointer and can be a disk, for example. It should also be noted that the display element 2 is described here as a special but non-limiting case of a rotating element, such as a rotating pointer 2. However, in principle, the present invention can also be applied to display elements 2 with non-circular motion trajectories, such as linear cursors, etc.

[0034] It should also be noted that when the measuring instrument is a chronograph, this hand 2 may be included in the display mechanism as an hour, minute or second hand 2 of variable length or variable radial extension.

[0035] refer to Figure 1 , the display hand 2 comprises a body 8 formed by a plate 8, the plate comprising a first end provided with a weight 9 and an opposite second end, the second end comprising a tip 10 indicating information, for example the time when the display mechanism is a display mechanism of a timepiece. In the plate 8, this tip 10 takes the shape of a triangle in this case, but may take any other suitable shape in order to indicate a specific angular position on the dial of the timepiece. The weight 9 is preferably rectangular in shape. However, the weight may take any other shape, for example, the weight 9 may take the shape of a logo.

[0036] In this pointer 2, the plate 8 also has a head located between the counterweight 9 and the tip 10 of the pointer 2. The head comprises a mounting portion 6 in which the drive shaft 3 can be incorporated or integrated, in particular in a tube 14 in an assembly area 7 of this portion 6. This assembly area 7 and therefore the tube 14 comprise an axial hole 5, also referred to as an “adjustment diameter”, which is provided for incorporating an embeddable end piece 4a of the drive shaft 3. It should be noted that the axial hole 5 has a surface area that is substantially smaller than the cross-section of the embeddable end piece 4a. The term “substantially smaller” is understood to mean “strictly smaller” or “substantially smaller”. The axial hole 5 has a surface area that is substantially smaller than the cross-section of the embeddable end piece 4a. Figure 1 Two opposing openings 15a, 15b are visible in FIG.

[0037] In this context, the plate 8 is made in whole or in part of a material with softening properties, such as a plastic material, in particular a thermoplastic material. Preferably, this material is a rigid material with softening properties. In these cases, the material can be heated sufficiently to soften and become rigid / hard again when cooled. This plastic material consists of a linear or branched polymer that is deformable and shaped under the action of heat. The plastic material includes, for example, a thermoplastic polymer.

[0038] Therefore, it is understood that the plate 8 can be made of this material having this softening property alone or completely. Alternatively, this plate 8 can be made of this material in part, wherein at least the mounting portion 6 and therefore the tube 14 are made of this material.

[0039] In this system 1, a drive shaft 3 comprising an axis of rotation A1 is also referred to as a "rotation shaft" or "drive shaft". Such shaft 3 comprises an embeddable end piece 4a configured to be incorporated, integrated into or combined with a tube 14 of an assembly area 7 of the mounting portion 6 of the plate 8 of the pointer 2. It should be noted that this end piece 4a is particularly configured to be attached or anchored in this area 7.

[0040] exist Figure 1 and Figure 3 In the embodiment, the drive shaft 3 comprises: a main part 4b, which is connected to the drive member of the display mechanism; and a free end of the shaft 3, which forms an embeddable end piece 4a (also called "pivot"). This end piece 4a is preferably formed as a single piece with the main part 4b of the shaft. Alternatively, the end piece 4a can be a part that is fastened to the main part 4b by being assembled to the part 4b by driving, bonding or welding in a non-limiting and non-exhaustive manner.

[0041] The shape of this embeddable end piece 4a is basically cylindrical. Of course, it is understood that the embeddable end piece can adopt other shapes. This embeddable end piece 4a is preferably made of a material having a softening point, which is higher than the softening point of the material constituting the mounting portion 6 and therefore also higher than the softening point of the material of the tube 14 on which the embeddable end piece may be combined, integrated or combined. This material is preferably a metal, such as aluminum, brass, steel or titanium. Alternatively, the material can also be a thermosetting material. It should be noted that the main part 4b of the shaft is preferably also made of the same material as the end piece 4a. Alternatively, the main part 4b can be made of a material different from the material of the end piece 4a, although this material must have a softening point that is substantially similar to the softening point of the material made of the embeddable end piece 4a.

[0042] In addition, Figures 1 to 3In the embodiment, the end piece 4a includes a portion of the peripheral wall 13 of the shaft 3, which is provided with an outer surface for coupling with the tube 14 of the mounting portion 6 of the plate 8, in particular a patterned outer coupling surface. This patterned outer surface includes a plurality of raised patterns 12. The plurality of patterns 12 preferably extend over the entire outer surface of the portion of the peripheral wall 13. Alternatively, the plurality of patterns 12 may be distributed over a specific area of ​​the outer surface, which is configured to cooperate with the material of the tube of the mounting portion 6 of the plate 8 constituting the pointer 2. It should be noted that these patterns 12 may be identical, i.e., have a similar three-dimensional shape, such as Figure 2 It should be noted that this three-dimensional shape is specifically configured to ensure that the end piece 4 a is firmly mechanically anchored in the tube 14 of this assembly zone 7 of the portion 6 .

[0043] This patterned outer surface helps to increase the contact surface of the end piece 4a with the material used in the tube of the mounting portion 6 of the plate 8. In addition, in this configuration, material can be inserted on and between the raised patterns 12 on the surface to ensure that the plate 8 is firmly retained on the end piece 4a. Therefore, it can be understood that the retention of the end piece 4a in the tube 14 of the portion 6 is then improved and thus helps to ensure optimal mechanical anchoring of the end piece in the tube 14.

[0044] As already mentioned, this end piece 4a of the shaft 3 is embedded in the tube 14 of this mounting portion 6 of the plate 8 by integration / combination or fusion. More specifically, this end piece 4a is embedded in this tube 14 of this portion 6 as a result of an operation of fusing / integrating / combining the materials constituting the end piece 4a of the shaft 3 and the tube 14 of this mounting portion 6, respectively. This operation softens the material constituting the portion 6 including the tube 14 by supplying energy to ensure that the end piece 4a is inserted and anchored in this mounting portion 6, and in particular in the tube 14 of the assembly area 7. Thus, in this assembly area 7 of the mounting portion 6 with said end piece 4a, the materials constituting said end piece 4a and said portion 6 including the tube 14 are bonded to each other by fusion, integration or combination, respectively, as a result of this energy supply. It should be noted that this energy can be supplied in a non-limiting and non-exhaustive manner by ultrasound or by a heating element, by a laser or by a steam jet.

[0045] In the case of using ultrasound, such an operation can be an ultrasonic fusion / integration / combination operation. This operation softens the material constituting the portion 6 including the tube 14 by applying mechanical vibrations to the portion 6, the mechanical vibrations being generated by ultrasound. In this context, these mechanical vibrations will then generate frictional heat in the portion 6 of the material having softening properties and excite its molecules, which in turn will begin to move. As a result, the material of the portion 6 including the tube 14 becomes more flexible as it softens, thereby allowing the end piece 4a to be inserted / embedded into the portion 6 and bonded to the material. In particular, the end piece 4a is then embedded in the axial hole 5 of the assembly area 7. In this context, the assembly area 7 clamps the end piece 4a in the tube 14 of the mounting portion 6, and thus helps to axially and rotatably retain the pointer 2 on the drive shaft 3.

[0046] In this configuration, with the end piece 4a arranged in the plate 8 of the pointer 2, it should be noted that the peripheral wall 13 comprising the end piece 4a projects on both sides of the opposite faces of the portion 6 of said plate 8 displaying the pointer 2. These two opposite faces are joined together by the side walls of this pointer 2. This arrangement of the end piece 4a in this portion 6 contributes to stabilizing the display pointer 2 axially and rotationally.

[0047] More specifically, the end piece 4a comprises a first and a second portion 16a, 16b, which protrude from two opposite openings 15a, 15b of the axial hole 5 of the tube 14, respectively. These first and second portions 16a, 16b delimit the surface of the end piece 4a on the peripheral wall 13 of the drive shaft 3. In this configuration, these first and second portions 16a, 16b of the end piece 4a have preferably similar thicknesses E3, E4. This thickness E3, E4 is less than the following thicknesses:

[0048] - the thickness E1 of the end piece 4a;

[0049] - Thickness E2 of tube 14 .

[0050] This arrangement of the end piece 4a in the tube 14 helps to stabilize the display pointer 1 axially and rotationally. Moreover, this arrangement helps to even out the stresses to which the pointer 2 may be subjected when it is assembled on the drive shaft and after it has been assembled on the shaft. In other words, this stress is evenly distributed over the entire thickness E2 of the body 8. This even distribution ensures that the body 8 of the pointer 2 and the portion 6 comprising the tube 14 remain flat. Therefore, the body 8 of the pointer 2 remains flat after being assembled on the shaft 3.

[0051] It will be appreciated that such an arrangement of the end piece 4a in the body 8 of the pointer 2 allows a wider range of materials to be used, in particular by making it less necessary to use particularly reinforced materials to prevent deformation of the pointer that might result from such stresses.

[0052] It should also be noted that the display pointer 2 is symmetrical with respect to the longitudinal plane of symmetry P1 and / or the transverse plane of symmetry P2 of the pointer 2. It should be understood that these two planes P1, P2 are perpendicular to each other. Due to the symmetry, this display pointer 2 is flippable, which helps to simplify and reduce the time spent on assembling it in the display mechanism. In other words, this display pointer 2 can be assembled on the shaft 3, and its visible face can be either of its two opposite faces.

[0053] The above description corresponds to a preferred embodiment and cannot be considered limiting in any case, and more particularly with regard to the type of display element 2 used in this system 1. More particularly, other display elements such as discs, in particular date discs, are also part of the invention.

[0054] Furthermore, this description is not limited to the forms described for the various structural elements or their materials constituting display element 2. A person skilled in the art will have no particular difficulty in selecting any other material having the necessary mechanical properties for implementing the invention, for example for plate 8 of pointer 2.

[0055] Since the invention can be implemented in any type of object or device, in particular in a portable object or device comprising a display element 2, the possible applications of this system 1 for attaching a display element 2 are numerous.

[0056] Reference numerals

[0057] 1 System for attaching display elements

[0058] 2 Display components

[0059] 3 Drive shaft

[0060] 4a Insertable end piece for drive shaft

[0061] 4b Main part of the drive shaft

[0062] 5 Display component shaft hole

[0063] 6 Display component installation section

[0064] 7 Display component assembly area

[0065] 8 Pointer display element or body of the plate

[0066] 9. Plate weight

[0067] 10 Tip of the board

[0068] 12+ patterns

[0069] 13 Outer wall of drive shaft

[0070] 14 Display element tube

[0071] 15a, 15b: first opening and second opening of the shaft hole

[0072] 16a, 16b The first and second parts protruding from the shaft hole

[0073] A1 Axis of rotation of the drive shaft

[0074] P1 Longitudinal symmetry plane P1 of display element / pointer

[0075] P2 Lateral symmetry plane P2 of display element / pointer

Claims

1. A system (1) for attaching a display element (2) to a drive shaft (3), the drive shaft being assembled to an analog display mechanism of a measuring instrument, the system (1) comprising a portion (6) made of a material having softening properties for mounting the display element (2) and an embeddable end piece (4a) of the drive shaft (3) configured to be bonded to the portion (6) by fusion, the end piece (4a) comprising a portion of an outer peripheral wall (13) of the drive shaft (3), the portion being provided with a patterned outer bonding surface, the patterned outer bonding surface being configured to mechanically anchor the end piece (4a) in the portion (6).

2. System (1) according to the preceding claim, wherein: The mounting portion (6) includes a tube (14) in which a shaft hole (5) is formed and configured to mount the display element (2) to the drive shaft (3).

3. System (1) according to the preceding claim, wherein: The embeddable end piece (4a) is joined to the tube (14) by fusion.

4. System (1) according to any one of the preceding claims, wherein: The patterned outer surface includes a plurality of raised patterns (12).

5. System (1) according to the preceding claim, wherein: The plurality of raised patterns (12) extend over all or part of the patterned outer surface.

6. System (1) according to any one of the preceding claims, wherein: The portions of the peripheral wall (13) of the end piece (4a) protrude respectively on both sides of the opposite faces of the mounting portion (6) of the display element (2).

7. System (1) according to any one of the preceding claims, wherein: The end piece (4a) includes a first portion and a second portion (16a, 16b) protruding from two opposite openings (15a, 15b) of the axial hole (5) of the tube (14), respectively.

8. System (1) according to any one of the preceding claims, wherein: The easily softenable material comprises in whole or in part a plastic material having softening properties.

9. System (1) according to any one of the preceding claims, wherein: The embeddable end piece (4a) is made of a material having a softening point higher than the softening point of the material constituting the mounting portion (6).

10. System (1) according to any one of the preceding claims, comprising a zone (7) for assembling the mounting portion (6) with the end piece (4a), wherein The materials constituting the end piece (4a) and the tube (14), respectively, are bonded to each other by fusion, integration or combination, in particular by fusion, integration or combination using ultrasound.

11. System (1) according to any one of the preceding claims, wherein: The display element (2) has a body (8) that is symmetrical relative to a longitudinal symmetry plane (P1) and / or a transverse symmetry plane (P2).

12. System (1) according to any one of the preceding claims, wherein: The display element (2) is a display pointer (2), the body (8) of which comprises a plate (8) provided with the assembly area (7).

13. Measuring instrument comprising at least one display element (2) mounted on an embeddable end piece (4a) of a drive shaft (3) using an attachment system (1) according to any of the preceding claims.

14. Measuring instrument according to the preceding claim, which is a timepiece.

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