System for mounting display elements and measuring instruments

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 even 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 several hands. These hands are attached to their drive shaft by a forcibly driven mounting system (i.e., a hollow cylinder). This mounting system, in this case a pipe, is forcibly pressed onto a mandrel with a diameter slightly larger than the inner diameter of the cylinder. This system utilizes the elastic and plastic properties of the material used, typically metal, for this driving operation. As a result, only hollow cylinders can be driven onto conventional rotating shafts, such as those used in mechanical watchmaking, whose diameters differ by only a few microns. Alternatively, this hollow cylinder, preferably a right-circular cylinder, can also be driven onto a frusto-conical rotating shaft, limiting excessively large driving forces that could damage the movement during this operation.

[0004] Furthermore, the mounting of the hands must provide sufficient force to hold the hands in place during shocks: the force required to drive conventional clock hands 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 the pipe, which means that the width of the slots must be extremely narrow in order to avoid making the pipe too weak. It should also be noted that in order to obtain the finest possible slots while respecting the width and length necessary to obtain the desired driving force, the machining operations are complex, increasing the cost and time of production. Summary of the Invention

[0007] SUMMARY OF THE INVENTION 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 that 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 in a measuring instrument.

[0009] Another object of the present invention is to provide a mounting system with reduced mass and inertia of the display element and with 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 present 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 the 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 incorporated into the pipe by melting The patterned outer 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 softenable 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 the shaft hole of the pipe, respectively; the implantable distal portion is made from a material that has a softening point higher than the softening point of the material comprising 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 each other by melting, combining or associating, in particular by ultrasonic 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 display element mounted on the implantable distal end of a drive shaft using such a mounting system.

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

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

[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 attached to the display mechanism of the instrument. [Figure 2] 1 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. [Figure 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 this embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] With reference 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 an object moving, 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 measuring instruments may be portable objects.

[0018] Referring to Figure 1, the system 1 includes a display element 2, more specifically a mounting portion 6 of the element 2, and a drive shaft 3, more specifically 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 to mount the display element 2 on the drive shaft 3. More specifically, the portion 6 includes 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 to mount the display element 2 on the drive shaft 3.

[0019] Such a display element 2, also referred to as a "display indicator", comprises a body 8 provided with a mounting portion 6. This mounting portion 6 comprises an assembly area 7 which includes a pipe 14. Into or together with the pipe 14 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 the embodiment of the mounting system 1, this display element 2 is preferably a display hand 2. However, as will be clearly understood, this display element 2 is obviously not limited to a hand 2, but may be something completely different, 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 hand 2. However, in principle, the invention is also applicable to display elements 2 with a non-circular movement trajectory, such as, for example, a linear 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 display hand 2 comprises a body 8 formed by a plate 8 having a first end provided with a counterweight 9 and a second, opposite end including a tip 10 indicating information such as the time if the display mechanism is that of a watch. In this plate 8, such tip 10 is triangular in shape in this case, but may also have any other suitable shape to indicate a particular angular position on the watch dial. The counterweight 9 is preferably rectangular in shape; however, it may also have any other shape, for example, the counterweight 9 may be in 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 includes 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, includes a shaft bore 5, also called the "adjustment diameter," which is provided for the assembly of the implantable end portion 4a of the drive shaft 3. It should be noted that this shaft bore 5 has a surface area substantially smaller than the cross-section of the implantable end portion 4a. The term "substantially small" is understood to mean "strictly small" or "essentially small." This shaft bore 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 with softening properties, such as a plastic material, in particular a thermoplastic material. Preferably, such a material is a hard material with softening properties. Under such conditions, the material softens when heated sufficiently and becomes hard / rigid again when cooled. The plastic material consists of a linear or branched polymer that can be deformed and shaped under the influence of heat. The plastic material includes, for example, a thermoplastic polymer.

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

[0026] In the system 1, the drive shaft 3 including the rotation axis A1 is also referred to as the "rotation shaft" or the "drive shaft." Such shaft 3 includes an embeddable end portion 4a configured to be incorporated into, integrated into, or associated with a pipe 14 in an assembly area 7 of the mounting portion 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 this area 7.

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

[0028] The implantable distal end 4a is substantially cylindrical in shape. It is understood, of course, that other shapes are possible. The implantable distal end 4a is preferably made of a material having a softening point higher than that of the material comprising the mounting portion 6, and therefore the material comprising 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, the material may be a thermosetting material. It should be noted that the main shaft portion 4b is also preferably made of the same material as the distal end 4a. Alternatively, the main portion 4b may be made of a material different from that of the distal end 4a, provided that such a material has a softening point substantially similar to that of the material comprising the implantable distal end 4a.

[0029] 1 to 3, the distal end 4a includes a portion of the peripheral wall 13 of the shaft 3. The peripheral wall 13 is provided with an outer surface, in particular a patterned outer joining surface, for joining with the pipe 14 of the mounting portion 6 of the plate 8. Such a 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 in specific areas of the outer surface, which are configured to cooperate with the material constituting the pipe of the mounting portion 6 of the plate 8 of the needle 2. It should be noted that the 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 the three-dimensional shape is configured in particular to ensure a robust mechanical fixation of the distal end 4a on the pipe 14 of the assembly area 7 of the portion 6.

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

[0031] As already mentioned, this end portion 4 a of the shaft 3 is embedded in the pipe 14 of this mounting part 6 of the plate 8 by merging / associating or melting. In particular, this end portion 4 a is embedded in the pipe 14 of this mounting part 6 as a result of an operation that melts / merges / associates the materials that respectively constitute the end portion 4 a of the shaft 3 and the pipe 14 of this mounting part 6. By such an operation, the material that constitutes the part 6 including this pipe 14 is softened by the supply of energy that ensures that the end portion 4 a is inserted and fixed in this mounting part 6, in particular in the pipe 14 in the assembly area 7. In other words, in this assembly area 7 of the mounting part 6 having said end portion 4 a, the material that constitutes said end portion 4 a and said part 6 including the pipe 14 are respectively assembled to one another by melting, merging or associating 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] When ultrasound is used, this operation may be an ultrasonic melting / merging / associating operation. This operation involves softening the material of the part 6, including the pipe 14, by applying mechanical vibrations to the part 6, which are caused by ultrasound. In this context, these mechanical vibrations generate frictional heat in the part 6, which has softening properties, and excite its molecules, causing them to move. That is, as the material of the part 6, including the pipe 14, softens, it becomes more flexible, allowing the end portion 4a to be inserted / embedded into the part 6 and bonded to it. In particular, the end portion 4a is then embedded in the shaft hole 5 of the assembly area 7. In this context, the assembly area 7 serves to clamp the end portion 4a to the pipe 14 of the mounting part 6, thereby axially and rotationally holding the needle 2 on the drive shaft 3.

[0033] It should be noted that in this configuration, in which the end portion 4a is arranged in the plate 8 of the hand 2, the 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 the side wall of this hand 2. Such an arrangement of the end portion 4a in this portion 6 serves to stabilize the indicator hand 2 axially and rotationally.

[0034] In particular, the end portion 4a includes first and second portions 16a, 16b that protrude from two opposing openings 15a, 15b, respectively, of the shaft bore 5 of the pipe 14. These first and second portions 16a, 16b define the surface area of the end portion 4a at the peripheral wall 13 of the drive shaft 3. In this configuration, the first and second portions 16a, 16b of the end portion 4a have thicknesses E3, E4 that are preferably similar. Such thicknesses E3, E4 are - smaller than the thickness E1 of the end portion 4a, Pipe thickness 14 is smaller than E2.

[0035] This arrangement of the end portions 4a on the pipe 14 helps to stabilize the indicator hand 1 axially and rotationally. Furthermore, this arrangement helps to even out the distribution of stresses that the needle 2 may be subjected to not only when it is assembled to the drive shaft, but also after it has been assembled to this shaft. In other words, these stresses are distributed evenly across the thickness E2 of the body 8. This even distribution ensures that the body 8 of the needle 2 and the portion 6 including the pipe 14 remain flat, i.e., the body 8 of the needle 2 remains flat after assembly to the shaft 3.

[0036] It will be appreciated that such an arrangement of the distal end 4a on the body 8 of the needle 2 allows for a wider range of materials to be used, particularly as it reduces the 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 plane of symmetry P1 and / or a transverse plane of symmetry P2 of the indicator hand 2. It will be understood that these two planes P1, P2 are perpendicular to each other. Due to this 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 to the shaft 3 with either of its two opposing faces as the visible face.

[0038] The above description corresponds to a preferred embodiment and cannot be considered limiting in any way, 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] Furthermore, the present specification is not limited to the described forms of the various structural elements or their materials that make up the display element 2. A person skilled in the art would have no particular difficulty in selecting any other material, for example for the plate 8 of the needle 2, that has the mechanical properties necessary for the implementation of the present 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 part of drive shaft 5 Shaft hole of display element 6 Mounting part of display element 7. Display element assembly area 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. A system (1) for mounting a display element (2) on a drive shaft (3) attached to an analog display mechanism of a measuring instrument, comprising: a mounting portion (6) for mounting the display element (2), the mounting portion (6) being made of a material having softening properties; an implantable distal end (4a) of the drive shaft (3) configured to be incorporated into the mounting portion (6) by melting the mounting portion (6); Including, The implantable end portion (4a) includes a portion of the peripheral wall (13) of the drive shaft (3) provided with a patterned outer interface surface configured to mechanically secure the implantable end portion (4a) in the mounting portion (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. 3. The system (1) according to claim 2, wherein the implantable end portion (4a) is incorporated into the pipe (14) by melting.

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

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

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

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

8. 2. The system (1) according to claim 1, wherein said 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 comprising the mounting portion (6).

10. 3. The system (1) according to claim 2, comprising an area (7) for assembling the mounting portion (6) to the implantable end portion (4a), wherein the materials constituting the implantable end portion (4a) and the pipe (14), respectively, are combined with each other by melting and merging 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. 11. The system (1) according to claim 10, wherein the display element (2) is a display hand (2), the body (8) of which comprises a plate (8) provided with the area (7).

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

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

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