System for attaching display element, and measuring instrument

Abstract

To provide a system for attaching a display element to a drive shaft fitted to an analog display mechanism of a measurement apparatus.SOLUTION: A system 1 disclosed herein comprises a portion 6 for mounting a display element 2 made of a material having a property of softening, and an embeddable end piece 4a of a drive shaft configured to be incorporated into a mounting portion by melting, the end piece including a part of a peripheral wall 13 of the drive shaft provided with a patterned outer bonding surface configured to mechanically anchor the end piece in the mounting portion.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to the field of measuring instruments, in particular to the field of watchmaking, and more particularly to the technical field of systems for mounting display elements, such as display hands, on the drive shaft of a display mechanism.

[0002] The invention further relates to a measuring instrument, such as a watch, including said display element mounted on said drive shaft using said mounting system. [Background technology]

[0003] In the prior art, a measuring instrument such as a clock includes a number of hands. These hands are attached to their drive shaft by a forcibly driven mounting system (i.e. a hollow cylinder). This mounting system is in this case a pipe, which is forcibly pressed into a mandrel with a diameter slightly larger than the inner diameter of the cylinder. In this system, the elastic and plastic properties of the material used, typically a metal, are used for the purpose of this drive operation. As a result, only hollow cylinders can be driven into conventional rotating shafts, the diameter of which differs by only a few microns, as used in mechanical watchmaking. Alternatively, this hollow cylinder, preferably a right circular cylinder, can also be driven into a frusto-conical rotating shaft, so as to limit excessively large driving forces that could damage the movement during this operation.

[0004] Furthermore, the mounting of the hand must provide sufficient force to hold the hand in place during shocks: the force required to drive a conventional clock hand is of the order of 30N.

[0005] One solution to these problems is to make the needle with a pipe that has one or more slots parallel to the axis of rotation and that open to the opposite end of the needle so that the pipe can deform elastically.

[0006] However, one major drawback of this solution is that the slots in the pipe weaken it. This means that the width of the slots must be extremely narrow in order not to make the pipe too weak. It should also be noted that in order to obtain the finest possible slots while respecting the width and length required to obtain the desired driving force, the machining operations are complex, increasing the costs and time of manufacture. Summary of the Invention

[0007] SUMMARY OF THE PRESENT EMBODIMENT It is an object of the present invention to overcome various drawbacks of the prior art.

[0008] Another object of the present invention is to provide a mounting system which improves the retention of a display element, which has a non-metallic body and is therefore insensitive to magnetic fields, to the drive shaft of a display mechanism of a measuring instrument.

[0009] Another object of the present invention is to provide a mounting system with reduced mass and inertia of a display element having any desired shape.

[0010] Another object of the present invention is to provide a mounting system in which the display element is robust over time and has reduced manufacturing costs.

[0011] Accordingly, one aspect of the invention relates to a system for mounting a display element on a drive shaft attached to an analog display mechanism of a measuring instrument, the system including a portion for mounting a display element made from a material having softening properties, and an embeddable distal end of the drive shaft configured to be incorporated into the portion by melting, the distal end including a portion of a peripheral wall of the drive shaft, the peripheral wall being provided with a patterned outer mating surface configured to mechanically secure the distal end to the portion.

[0012] In another embodiment, the mounting portion includes a pipe having a shaft hole formed therein and configured to mount the display element to the drive shaft; The embeddable end is integrated into the pipe by melting The patterned exterior surface includes a plurality of raised patterns; the plurality of raised patterns extend across all or a portion of the patterned exterior surface; a portion of the peripheral wall of the end portion protrudes on each side of the opposing surface of the mounting portion of the display element; The softening material includes a plastic material that has softening properties in whole or in part, the end portion includes a first portion and a second portion protruding from two opposing openings of a shaft hole of the pipe, the implantable distal portion is made from a material that has a softening point higher than the softening point of the material that comprises the mounting portion; an area for assembling a mounting part to the end part, in which the materials constituting the end part and the pipe, respectively, are joined to one another by melting, combining or associating, in particular by ultrasonically melting, combining or associating, the display element has a body that is symmetrical with respect to a longitudinal and / or transverse plane of symmetry, The display element is a display hand, the body of which comprises a plate provided with an assembly area.

[0013] Another aspect of the invention relates to a metrology instrument including at least one such indicating element mounted to an implantable distal end of a drive shaft using such a mounting system.

[0014] Advantageously, such an instrument is a clock. [Brief description of the drawings]

[0015] Other characteristics and advantages of the present invention will be better understood on reading the given following description of specific non-limiting embodiments of the invention, given by way of illustration and with reference to the accompanying drawings, in which:

[0016] [Figure 1]1 is a diagram of a system for mounting a display element, according to one embodiment of the present invention, mounted on an implantable distal end of a drive shaft that is attached to the display mechanism of the instrument. [Diagram 2] FIG. 2 is a top view of a mounting system in which the distal end of the shaft is incorporated into, integrated with, or associated with the pipe of the display element, according to one embodiment of the present invention. [Diagram 3] 3 is a longitudinal cross-sectional view of the mounting portion of the display element shown in FIG. 2 along line III-III according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Please refer to Figures 1 to 3. The present invention relates to a system 1 for mounting a display element 2 on the drive shaft 3 of an analog display mechanism of a mechanical, electronic or hybrid measuring instrument. This device serves in a non-limiting and non-exhaustive manner to measure the speed of movement of an object, in the case of a tachometer, the air pressure, in the case of a barometer, or the time, in the case of a clock such as a wristwatch. It should be noted that such a measuring instrument may be a portable object.

[0018] With reference to Figure 1, the system 1 comprises a display element 2, more particularly a mounting portion 6 of the element 2, and a drive shaft 3, more particularly an end portion 4a of the shaft 3. In the system 1, the end portion 4a and the portion 6 are configured to cooperate with each other in order to mount the display element 2 on the drive shaft 3. In particular, the portion 6 comprises a pipe 14 provided with a shaft hole 5. The shaft hole is configured to mount the display element 2 on the drive shaft 3. In other words, the pipe 14 and the end portion 4a are configured to cooperate with each other in order to mount the display element 2 on the drive shaft 3.

[0019] Such a display element 2, also called "display indicator", comprises a body 8 provided with a mounting part 6. This mounting part 6 comprises an assembly area 7 including a pipe 14 in which or together with which is incorporated, integrated or associated a drive shaft 3 of a drive member of the display mechanism. It should be noted that the invention is applicable to analog display mechanisms of mechanical, electronic or hybrid timepieces.

[0020] In an embodiment of the mounting system 1, this display element 2 is preferably a display needle 2. However, as will be clearly understood, this display element 2 is obviously not limited to a needle 2 but can be something completely different therefrom, for example a disk. It should also be noted that this display element 2 is described here in the specific but non-limiting case of a rotating element such as a rotating needle 2. However, in principle the invention is also applicable to display elements 2 with a non-circular movement trajectory, such as for example a straight line cursor.

[0021] It should also be noted that, if the measuring instrument is a clock, this hand 2 may be included in the display mechanism as an hour, minute or second hand 2 having a variable length or variable radial extension.

[0022] With reference to figure 1, this indicator hand 2 comprises a body 8 formed by a plate 8 comprising a first end provided with a counterweight 9 and a second opposite end comprising a tip 10 indicating information, such as the time, if the indicator mechanism is that of a watch. In this plate 8, such tip 10 presents in this case a triangular shape, but may present any other suitable shape so as to indicate a particular angular position on the dial of the watch. The counterweight 9 is preferably rectangular in shape. However, it may present any other shape, for example the counterweight 9 may present the shape of a logo.

[0023] In this needle 2, the plate 8 also has a head located between the counterweight 9 and the tip 10 of the needle 2. Such a head comprises a mounting part 6, in which the drive shaft 3 can be assembled or integrated, in particular in a pipe 14 in an assembly area 7 of this part 6. Such assembly area 7, and thus the pipe 14, comprises a shaft hole 5, also called "adjustment diameter", which is provided for accommodating the implantable end part 4a of the drive shaft 3. It should be noted that this shaft hole 5 has a surface area substantially smaller than the cross section of the implantable end part 4a. The term "substantially small" is understood to mean "strictly small" or "essentially small". This shaft hole 5 has two opposing openings 15a, 15b visible in FIG. 1.

[0024] In this context, the plate 8 is made entirely or partly from a material having softening properties, such as a plastic material, in particular a thermoplastic material. Preferably, such a material is a hard material having softening properties. Under such conditions, the material is heated sufficiently to soften it and becomes hard / rigid again when cooled. The plastic material consists of linear or branched polymers that can be deformed and shaped under the effect of heat. The plastic material includes, for example, thermoplastic polymers.

[0025] It will therefore be understood that this plate 8 can be made exclusively or entirely from this material having this softening property, or alternatively such a plate 8 is made partially from this material, with at least the mounting part 6 and thus the pipe 14 being made from this material.

[0026] In the system 1, a drive shaft 3 including a rotation axis A1, also referred to as a "rotation shaft" or a "drive shaft", includes an embeddable end portion 4a configured to be embedded, integrated or associated with a pipe 14 in an assembly area 7 of the mounting part 6 of the plate 8 of the needle 2. It should be noted that the end portion 4a is specifically configured to be attached or fixed to the area 7.

[0027] 1 and 3, the drive shaft 3 comprises a main part 4b connected to the drive member of the indicator mechanism and a free end forming an embeddable end part 4a, also called the "pivot" of said shaft 3. Such end part 4a is preferably integrally formed with said main part 4b of the shaft. Alternatively, said end part 4a may be a part fastened to said main part 4b and assembled to said part 4b in a non-limiting and non-exhaustive manner by driving, joining or welding.

[0028] The shape of such an implantable end portion 4a is substantially cylindrical. Of course, it is understood that it may assume other shapes. Such an implantable end portion 4a is preferably made of a material having a softening point higher than that of the material constituting the mounting portion 6 and thus of the pipe 14 with which it is likely to be incorporated, integrated or associated. Such a material is preferably a metal such as aluminum, brass, steel or titanium. Alternatively, this material may be a thermosetting material. It should be noted that the main portion 4b of the shaft is also preferably made of the same material as this end portion 4a. Alternatively, this main portion 4b may be made of a material different from that of the end portion 4a. However, such a material must have a substantially similar softening point as the material constituting this implantable end portion 4a.

[0029] 1 to 3, this end portion 4a comprises a part of the peripheral wall 13 of the shaft 3. This peripheral wall 13 is provided with an outer surface, in particular a patterned outer joining surface, for joining with the pipe 14 of this mounting part 6 of the plate 8. Such a patterned outer surface comprises a plurality of raised patterns 12. This plurality of patterns 12 preferably extends over the entire outer surface of this part of the peripheral wall 13. Alternatively, this plurality of patterns 12 may be distributed in a specific area of ​​this outer surface, which is configured to cooperate with the material constituting the pipe of this mounting part 6 of the plate 8 of the needle 2. It should be noted that these patterns 12 may be identical, i.e. have a similar three-dimensional shape, as can be seen in FIG. 2. It should be noted that this three-dimensional shape is configured in particular to ensure a robust mechanical fixation of the end portion 4a on the pipe 14 of this assembly area 7 of this part 6.

[0030] Such a patterned outer surface serves to increase the contact surface of the end portion 4a with the material used for the pipe of the mounting portion 6 of the plate 8. Furthermore, in this configuration, material may be inserted on and between the raised patterns 12 of the surface to ensure that the plate 8 is securely held on the end portion 4a. It will thus be appreciated that the retention of the end portion 4a of the portion 6 on the pipe 14 is improved in this case, thus helping to ensure an optimal mechanical fixation thereof on the pipe 14.

[0031] As already mentioned, this end 4a of the shaft 3 is embedded in the pipe 14 of this mounting part 6 of the plate 8 by integration / association or melting. In particular, this end 4a is embedded in the pipe 14 of this mounting part 6 as a result of an operation that melts / integrates / associates the materials constituting the end 4a of the shaft 3 and the pipe 14 of this mounting part 6, respectively. By such an operation, the material constituting the part 6 including this pipe 14 is softened by the supply of energy that ensures that the end 4a is inserted and fixed in this mounting part 6, in particular in the pipe 14 in the assembly area 7. That is to say, in this assembly area 7 of the mounting part 6 with said end 4a, the material constituting said end 4a and said part 6 including the pipe 14 are respectively incorporated into one another by melting, integration or association due to the supply of energy. It should be noted that this energy may be supplied by ultrasound or a heating element, a laser or a steam jet, in a non-limiting and non-exhaustive manner.

[0032] In the case of using ultrasound, such an operation may be an ultrasonic melting / merging / associating operation. This operation consists in softening the material of the part 6 including the pipe 14 by applying mechanical vibrations to said part 6, said mechanical vibrations being due to ultrasound. In this context, these mechanical vibrations generate frictional heat in the part 6 of the material that in this case has the property of softening, exciting its molecules, which then start to move. That is to say, as the material of this part 6 including the pipe 14 softens, it becomes more flexible, allowing the insertion / embedding of the end part 4a into this part 6 and allowing its joining to this material. In particular, this end part 4a is then embedded in the shaft hole 5 of the assembly area 7. In this context, the assembly area 7 serves to clamp this end part 4a to the pipe 14 of this mounting part 6, and thus to hold the needle 2 axially and rotationally to the drive shaft 3.

[0033] It should be noted that in this configuration, in which the end portion 4a is arranged on the plate 8 of the hand 2, a peripheral wall 13 including the end portion 4a projects on both sides of the opposing faces of the portion 6 of said plate 8 of the indicator hand 2. These two opposing faces are joined together by a side wall of this hand 2. Such an arrangement of the end portion 4a on this portion 6 serves to stabilize the indicator hand 2 axially and rotationally.

[0034] In detail, said end part 4a comprises a first part 16a, 16b protruding from two opposing openings 15a, 15b, respectively, of the shaft bore 5 of the pipe 14. These first and second parts 16a, 16b define the surface area of ​​the end part 4a at the peripheral wall 13 of the drive shaft 3. In this configuration, these first and second parts 16a, 16b of the end part 4a have thicknesses E3, E4, which are preferably similar. Such thicknesses E3, E4 are: - smaller than the thickness E1 of the end portion 4a, · The thickness of pipe 14 is smaller than E2.

[0035] Such an arrangement of the ends 4a on the pipe 14 serves to stabilize the indicator needle 1 axially and rotationally. Moreover, this arrangement serves to even out the distribution of stresses that the needle 2 may be subjected to, not only when it is assembled on the drive shaft, but also after it has been assembled on this shaft. In other words, such stresses are distributed evenly over the entire thickness E2 of the body 8. This even distribution ensures that the body 8 of the needle 2 and the part 6 including the pipe 14 remain flat, i.e. the body 8 of the needle 2 remains flat after assembly on the shaft 3.

[0036] It will be appreciated that such an arrangement of the distal ends 4a on the body 8 of the needle 2 allows for a wider range of materials to be used, particularly as there is less need to use materials that are explicitly reinforced to prevent needle deformation that may result from such stresses.

[0037] It should also be noted that the indicator hand 2 is symmetrical with respect to a longitudinal symmetry plane P1 and / or a transverse symmetry plane P2 of said hand 2. It will be understood that these two planes P1, P2 are perpendicular to each other. Due to the symmetry, such an indicator hand 2 can be inverted, which helps to simplify and reduce the time required for assembly in the display mechanism. In other words, such an indicator hand 2 can be assembled on the shaft 3 with either one of its two opposing faces as the visible face.

[0038] The above description corresponds to a preferred embodiment and cannot in any way be considered limiting, in particular with regard to the type of display element 2 used in this system 1. In particular, other display elements such as discs, in particular date discs, are also part of the invention.

[0039] Moreover, the present specification is not limited to the described forms of the various structural elements or their materials constituting the display element 2. A person skilled in the art will have no particular difficulty in selecting, for example for the plate 8 of the needle 2, any other material having the mechanical properties necessary for the implementation of the invention.

[0040] The possible applications of this system 1 for mounting a display element 2 are very numerous, since the invention can be implemented in any type of object or device, in particular a portable object or device that includes a display element 2. [Explanation of symbols]

[0041] 1. System for mounting display elements 2 Display elements 3 Drive shaft 4a. Implantable end of drive shaft 4b Main parts of the drive shaft 5 Shaft hole of display element 6 Mounting part of display element 7. Mounting area for display elements 8 Body of display element or hand plate 9 Plate counterweight 10 Plate tip 12 Multiple Patterns 13 Drive shaft peripheral wall 14 Display Component Pipes 15a, 15b First and second openings of the shaft hole 16a, 16b: First and second portions protruding from the shaft hole A1 Drive shaft rotation axis P1 Longitudinal symmetry plane of display element / hand P1 P2 Short-side symmetry plane of display element / hand P2

Claims

1. 1. A system (1) for mounting a display element (2) on a drive shaft (3) attached to an analog display mechanism of a measuring instrument, the system (1) comprising: a part (6) for mounting the display element (2) made from a material having softening properties; and an embeddable end portion (4a) of the drive shaft (3) configured to be incorporated into the part (4a) by melting, the end portion (4a) comprising a portion of a peripheral wall (13) of the drive shaft (3) provided with a patterned outer mating surface configured to mechanically fix the end portion (4a) in the part (6).

2. 2. The system (1) according to claim 1, wherein the mounting portion (6) comprises a pipe (14) in which a shaft hole (5) is made and configured to mount the display element (2) on the drive shaft (3).

3. 2. The system (1) according to claim 1, wherein the embeddable end portion (4a) is incorporated into the pipe (4) by melting.

4. The system (1) of claim 1, wherein the patterned exterior surface comprises a plurality of raised patterns (12).

5. The system (1) of claim 1, wherein the patterned exterior surface includes a plurality of raised patterns (12) extending across all or a portion of the patterned exterior surface.

6. 2. The system (1) according to claim 1, wherein the portion of the peripheral wall (13) of the end portion (4a) projects on each side of the opposing face of the mounting portion (6) of the display element (2).

7. 2. The system (1) according to claim 1, wherein the end portion (4a) comprises a first portion (16a, 16b) protruding from each of the two opposing openings (15a, 15b) of the shaft hole (5) of the pipe (14).

8. The system (1) according to claim 1, wherein the material prone to softening comprises, in whole or in part, a plastic material having softening properties.

9. 2. The system (1) according to claim 1, wherein the implantable distal portion (4a) is made from a material having a softening point higher than the softening point of the material constituting the mounting portion (6).

10. 2. The system (1) according to claim 1, comprising an area (7) for assembling the mounting part (6) to the end part (4a), the materials constituting the end part (4a) and the pipe (14) respectively being integrated into one another, in particular by melting, merging or associating using ultrasound.

11. 2. The system (1) according to claim 1, wherein the display element (2) has a body (8) that is symmetrical with respect to a longitudinal plane of symmetry (P1) and / or a transverse plane of symmetry (P2).

12. 2. The system (1) according to claim 1, wherein the display element (2) is a display hand (2), the body (8) of which comprises a plate (8) provided with the mounting area (7).

13. A measuring instrument including at least one display element (2) mounted on an embeddable end portion (4a) of a drive shaft (3) using a mounting system (1) according to claim 1.

14. The device of claim 13, wherein the device is a watch.

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