Device for fastening a back cover on an intermediate piece of a timepiece

Abstract

The invention relates to a device for fastening a back cover on an intermediate piece of a watch, the back cover having a shoulder forming a cover plate arranged to cover completely or partially the intermediate piece, the shoulder being arranged to rest inside the intermediate piece, the device comprising at least one pin integral with the intermediate piece and a washer mounted between the back cover and the intermediate piece. According to the invention, the back cover comprises, near its periphery, at least one recess in which the pin is arranged to slide between a first position, called insertion position, in which the back cover is free, and a second position, called locking position, in which the back cover is locked and angularly positioned relative to the intermediate piece, the recess comprising at least one bump to create a hard point and increase the torque during passage of the pin through the bump.

Description

Technical Field

[0001] The present invention relates to a device for fastening the back cover to the middle part of a watch.

[0002] The present invention also relates to clocks and watches, particularly wristwatches, that include such a device. Background Technology

[0003] External parts of watches and similar devices are subject to many restrictions, particularly in terms of water resistance, robustness, and appearance, and must be manufactured in a manner that prevents any accidental disassembly that would irreparably lead to after-sales intervention for gasket replacement, cleaning, lubrication, or even repair.

[0004] Some external parts or control components must also be angularly indexed relative to each other for initial reference, rest, or actuation positioning, or to facilitate reading indications or scales, or to ensure the continuity of ramps and / or decorations. Such angular indexing is often difficult to perform well when combined with good component fastening and perfect waterproofing of gaskets. Summary of the Invention

[0005] This invention proposes the manufacture of a waterproof and reliable assembly with external components featuring easily achievable angular calibration.

[0006] Therefore, the present invention relates to a device for fastening a back cover to a watch center piece, the back cover having a shoulder and a body, the shoulder forming a cover plate arranged to completely or partially cover the center piece, the body being arranged to rest in the center piece, the device comprising a ring installed between the back cover and the center piece and integral with the center piece, and at least one pin integral with the back cover and arranged to cooperate with the ring and the center piece.

[0007] According to the invention, the ring includes at least one recess arranged to engage with the pin, the pin being slidable in the recess between a first position (referred to as the insertion position, where the back cover is free) and a second position (referred to as the locking position, where the back cover is locked and angularly positioned relative to the middle member), and the recess includes at least one bump to form a hard spot and increase torque during the pin's passage through the bump.

[0008] Other advantageous variations according to the invention:

[0009] - The pin is mounted on the rear cover, and the pin has a body, a head and a foot, the diameter of the body and the foot being smaller than the diameter of the head;

[0010] - The intermediate part includes a shoulder for receiving the ring, the shoulder having at least one hole for securing the ring to the intermediate part via fasteners;

[0011] - The intermediate component includes at least one hollow portion arranged to engage with the head of the pin, the head of the pin sliding within the hollow portion.

[0012] - The ring is made of an elastically deformable material, such as polyoxymethylene, polyurethane, polymer-based materials, or elastomeric materials;

[0013] - The pin is made of metal or a metal alloy;

[0014] - The recess extends according to a radius of the ring and is through so that the pin slides through the recess;

[0015] - The recess includes a first end and a second end, as well as two walls, the distance between which is equal to the diameter of the body of the pin, so as to guide the pin and axially retain the pin;

[0016] - The first end forms a space for inserting the pin, and the second end forms a stop to hold the pin in place;

[0017] - The dimensions of the first end are similar to those of the head of the pin, and the dimensions of the second end are similar to those of the body of the pin;

[0018] -The protrusion is formed on one of the two walls of the recess;

[0019] -The recess includes multiple protrusions, and the distance between each protrusion is the same;

[0020] -The recess includes multiple protrusions, and the distance between the protrusions gradually decreases;

[0021] - The device includes at least three pins that are angled and spaced regularly on the back cover.

[0022] The present invention also relates to a clock or watch that includes such a fastening device. Attached Figure Description

[0023] Other features and advantages of the invention will become more apparent after reading the following description of specific embodiments of the invention, given by way of simple illustrative and non-limiting examples, and in conjunction with the accompanying drawings, in which:

[0024] - Figure 1 This is an exploded perspective view of the fastening device according to the present invention;

[0025] - Figure 2a and 2b These are perspective views of the rear cover and the middle component of the fastening device according to the present invention;

[0026] - Figures 3a to 3b These are perspective views of the ring and pin of the fastening device according to the present invention;

[0027] - Figure 3c A cross-sectional view of the fastening device according to the present invention is shown. Detailed Implementation

[0028] The present invention proposes to manufacture a waterproof and reliable assembly of an external component, which has an angular calibration that is easy to perform and is in a guaranteed position, and this is achieved using a minimum number of components.

[0029] Figures 1 to 3c A non-limiting example of the mounting and angular alignment of the back cover relative to the watch's centerpiece is shown.

[0030] This invention relates to a fastening device 100 for securing a back cover 2 to a center piece 1 of a watch. The fastening device 100 includes a ring 3 installed within the center piece, at least one pin 4 integral with the back cover and arranged to engage with the ring 3, and a washer installed on the back cover 2. The reverse installation is obviously possible, whereby the pin 4 is installed on the center piece 1, and the ring 3 is installed on the back cover 2, which may be solid or transparent.

[0031] The rear cover 2 is arranged to switch from a first disassembly insertion position to a second assembly locking position. For example... Figure 2a As shown, the rear cover 2 has a shoulder 21 that is slightly raised relative to the cover plate and forms a groove 20 around the periphery of the rear cover. The rear cover 2 is arranged to completely or partially cover the intermediate member 1 and includes a body 22 arranged to rest in the empty space 14 of the intermediate member 1.

[0032] According to the invention, the fastening device includes at least one pin 4 arranged axially between the rear cover 2 and the intermediate piece 1, fastening it non-rotatably relative to one of them, and sliding in the recess 5 of the ring 3.

[0033] The pin 4 includes a head 40, a body 42, and a foot 43 equipped with a groove 41. The pin 4 is screwed into the rear cover 2 to make it integral with the rear cover. As shown, the body 42, head 40, and foot 43 are cylindrical, with the diameter of the head 40 being larger than the diameter of the body 42 and the foot 43. The pin 4 is screwed onto the rear cover 2, which includes at least one threaded hole for receiving the foot 43 of the pin 4. The pin 4 is preferably made of metal or a metal alloy such as steel. Of course, shapes other than grooves can be used to secure the pin, such as star-shaped or cross-shaped.

[0034] As in Figure 3aAs can be observed, ring 3 is formed by an arc-shaped / ring-shaped member 30 and includes at least one recess 5 arranged to engage with pin 4. Pin 4 is arranged to slide in recess 5 between a first position (referred to as the insertion position, where the back cover 2 is free) and a second position (referred to as the locking position, where the back cover 2 is locked and angularly positioned relative to the intermediate member 1). Recess 5 includes at least one protrusion 55 to form a hard point and increase torque as pin 4 passes through protrusion 55. This arrangement also ensures security against loosening and thus loss of waterproofness.

[0035] To make the ring portion of the receiving recess 5 more rigid, the width of this portion is greater than the rest of the ring, so that the ring is pressed between the back cover 2 and the intermediate piece 1 at the wider portion.

[0036] Ring 3 may be made of a material selected from: polyoxymethylene, polyurethane, polymer-based materials, or elastomers, such as those known to exist. or The choice of material, the interference geometry with the pin, and the pin material allow for the determination of the maximum tightening torque. The advantage of this ring 3, preferably made of a polymeric elastic material or similar material, is its ease of manufacture and replacement in case of breakage or wear.

[0037] Ring 3 is fastened to intermediate member 1 by screw 6, which passes through ring 31 and is screwed into hole 13 of intermediate member 1. Advantageously, the head of screw 6 rests in a countersunk hole formed at hole 31 on the surface of ring 3. Ring 3 rests against the back 12 and wall 11 of shoulder 10 of intermediate member 1, which has a similar size to the ring, such that the surface of ring 3 is flush with the edge of intermediate member 1. Advantageously, the back 12 of shoulder 10 has at least one hollow portion 15 extending according to a radius of intermediate member, the position of which, once ring is installed, corresponds to the position of recess 5 of ring. The width of hollow portion 15 is set to be greater than the width of recess 5, the width of which is equivalent to the size of body 42 of pin 4, and the width of hollow portion 15 is at least equivalent to the width of head 40 of pin 4, such that pin 4 can move in hollow portion 15 and be axially held in recess 5. It should be noted that the length of the hollow section 15 limits the stroke length of the pin 4.

[0038] In the first insertion / removal position, the middle piece 1 and the rear cover 2 have a first angular orientation relative to each other.

[0039] According to the invention, the rear cover 2 includes a radial waterproofing device at the interface between the intermediate member 1 and the rear cover 2, such as an O-ring gasket (not shown), which rests in a groove 20 of the cover plate and thus fills the space formed by the shoulder 21 at the periphery of the rear cover. The transition from the first insertion / disassembly position to the second assembly / locking position is performed under loads applied by the operator: an axial load to overcome the resistance of the O-ring gasket and assemble the rear cover 2 and the intermediate member 1, and a torque to bring them into the angularly calibrated position.

[0040] In the second assembled and locked position, the intermediate piece 1 and the rear cover 2 have a second angular orientation relative to each other, different from the first angular orientation. The rear cover 2 and the intermediate piece 1 are axially held together by means of a bayonet engagement.

[0041] Advantageously, the locking mechanism between the back cover 2 and the intermediate piece 1, particularly around the axial direction D, is reversible and allows for disassembly. In a manner characteristic of this invention, such disassembly requires a load on the operator's side similar to that applied during assembly, and preferably requires the use of special tools, for example, that engage with holes or peripheral recesses on the visible surface of the back cover 2. This assembly method prevents the wearer from removing the back cover, or from disassembly due to reckless actions or vibrations.

[0042] The body portion 42 of the pin is arranged to mate with at least one complementary protrusion, such as a protrusion 55, included in the recess 5 of the ring 3. Figure 3a As shown, the ring 3 includes at least one recess 5 extending according to a radius of the ring 3 and having a width dimension equivalent to the diameter of the body portion 42 of the pin 4, so that the pin 4 can slide within the recess 5. The recess 5 includes a first end 51 and a second end 52, as well as two walls 53.

[0043] Therefore, each time the pin 4 passes through the protrusion 55 in the recess 5, it generates a resistance torque that tends to resist the relative rotational movement between the intermediate piece 1 and the back cover 2.

[0044] According to a preferred embodiment, the recess 5 includes a plurality of protrusions 55 arranged to apply continuous resistance during the passage of the pin 4. According to the invention, in the same recess 5, the angular distance between successive protrusions 55 is reduced in such a way that an increased resistance is applied during rotation between the rear cover 2 and the intermediate member 1. The angular distance between successive protrusions 55 can also be kept constant to apply a constant resistance torque.

[0045] Various configurations of the protrusion arrangement can be achieved. According to a first embodiment, one or more protrusions 55 are present on a single sidewall of the recess 5. According to a second embodiment, one or more protrusions 55 are provided on both sidewalls of the recess 5, with the protrusions 55 on each wall positioned opposite to each other. According to a third embodiment, one or more protrusions 55 are provided on both sidewalls of the recess 5, with the protrusions 55 on each wall offset relative to each other. Similarly, the distance between the relatively positioned protrusions 55 can be varied to provide a gradually increasing drag torque.

[0046] The first end 51 of the recess 5 forms a space for inserting the head 40 of the pin 4, and the second end 52 forms a stop and holds the pin 4 in the proper position in the recess 5; for this purpose, the size of the first end 51 is slightly larger than the size of the head 40 of the pin 4, and the size of the second end 52 is similar to the body 42 of the pin 4 (considering the final manufacturing tolerances).

[0047] It should be understood that as the number of recesses 5 and protrusions 55, the size of the protrusions, and the size of the mating additional pins 4 increase, the drag torque becomes greater. Therefore, the number of consecutive protrusions 55, and / or the number of pins and recesses, can be varied. According to a preferred embodiment of the invention, the ring 3 includes three recesses 5 distributed angularly in a regular manner, and the rear cover 2 includes three complementary pins 4.

[0048] Of course, the configuration can be reversed, in which ring 3 is integrated with back cover 2 and pin 4 is integrated with intermediate part 1.

[0049] It is conceivable to remove the six fastening screws 6 and add three additional pins 4 fastened to the intermediate piece 1. This would add three additional grooves and would also provide disassembly resistance on axis D via this double bayonet.

[0050] It is also conceivable to have two pins on the middle part and two pins on the back cover, so that only four grooves need to be made.

[0051] During assembly, the operator places the back cover 2 on the intermediate piece 1, aligning the heads 40 of one or more pins 4 with the first ends 51 of one or more recesses 5. This allows the pins 4 to be positioned within the recesses 5 when the operator applies a translational movement along axis D on the back cover 2 to position the cover plate 20 of the back cover 2 close to the lower edge 16 of the intermediate piece 1. The pins abut against the back of the hollow portion 15, thus ensuring water resistance due to the gasket. The friction of the O-ring gasket provides initial resistance. The height of the pins 4 is slightly greater than the distance between the back of the hollow portion 15 and the back cover 2, preventing contact between the back cover 2 and the intermediate piece 1, and allowing a clearance of 0.02 mm to 0.04 mm between the back cover and the intermediate piece.

[0052] Subsequently, the operator applies an increasing torque to induce relative rotation between the intermediate piece 1 and the rear cover 2. During this rotation, the operator performing the assembly encounters a second resistance as the body 42 of the pin 4 engages with the first protrusion 55 of the recess 5. Therefore, the resistance torque gradually increases during the complete passage through the protrusion 55.

[0053] In the first case, the first protrusion 55 that mates with pin 4 is a single protrusion. In the second case, the recess 5 includes multiple protrusions 55, causing the operator to apply load in a jerky manner during rotation, with the accumulated resistance torque peaking increasing with each passage through a hard point to reach its maximum at the calibrated angle. The operator experiences increased resistance due to the protrusions and the stronger "pin-protrusion" interference when the case is closed by rotating the back cover.

[0054] like Figure 1 and Figure 3a As shown, ring 3 includes three recesses 5 distributed at 120° intervals, each recess 5 being arranged to engage with a pin 4, which is complementary to the recess 5. Therefore, the back cover 2 includes three pins 4 distributed at 120° intervals, and when the three pins 4 at 120° intervals pass through the protrusion 55 simultaneously, the operator will feel a single passage through a hard point.

[0055] Waterproofing is achieved once the back cover 2 is placed on the intermediate member 1, and the mechanism according to the invention is arranged such that, as with the case of the single front protrusion, waterproofing of the gasket is ensured once the back cover is inserted into the intermediate member, and thereafter it will not loosen without the intentional action of an operator.

[0056] In practice, using at least two, preferably three, or even four consecutive bumps yields very good results, thus providing sufficient basic angular travel through each bump.

[0057] During assembly, the invention requires traversing multiple bumps consecutively, creating increased resistance. The same applies during disassembly, because from the final calibration position, particularly on the mechanical stop, in the worst case, any sudden load application would translate into traversing a single bump 55 without complete disassembly, resulting in visual distortion, but most importantly, without loss of water resistance or risk of contaminating the watch's interior. In the illustrated example, water resistance is consistently ensured even when the operator traverses three optically visible thresholds consecutively due to distortion. To lose water resistance, the operator must partially remove the back cover 2 to prevent the gasket from being compressed further.

[0058] According to one embodiment, the distance between each bump 55 is the same, and their passage will generate the same drag torque.

[0059] In a favorable variation, the distance between the bumps gradually decreases, and the operator must apply a gradually increasing torque.

[0060] This invention is advantageous because it is perfectly compatible with watch sizes while providing high resistance of 1.2 Nm ± 0.2 Nm depending on the diameter of the watch.

[0061] Furthermore, when the watch is subject to a significant degree of specific constraints, the disassembly of the mechanism according to the invention requires maintaining the application of possible forces from unexpected sources during a significant angular travel (5 to 10° for crossing a single bump in the example shown), and safety is also guaranteed if the multiple bumps are consecutive.

[0062] According to the present invention, angular calibration is ensured by forming the second end 52 of the travel limit stop.

[0063] Therefore, the present invention can prevent any unintended and unintentional disassembly of the back cover of the intermediate component, for example, under the influence of vibration, under the influence of continuous expansion cycles, due to the wearer's misuse or other reasons.

[0064] Preferably, disassembly requires specialized tools that are not commercially available, to ensure that the repairs are performed by qualified after-sales personnel.

[0065] This invention is well suited for situations where the middle section and the case back are made of different materials with different coefficients of thermal expansion or of fragile or hard materials (ceramic, sapphire) that do not allow for standard fastening methods. Examples of conventional configurations include assembling the middle section into or together with the sapphire case back, or examples of cases made entirely of ceramic, metal-ceramic compositions, or similar materials.

[0066] One important advantage of this invention is that it eliminates any contact / friction between the back cover and the middle part, thereby preventing the presence of residues caused by friction, as is the case in the prior art, and the need to add grease to limit them.

[0067] Another important advantage of the invention is that it increases safety when opening because it involves passing through multiple notches in succession and requires at least partial removal of the back cover to prevent any loss of waterproofing.

[0068] The present invention also relates to a clock or watch that includes such a fastening device.

[0069] In summary, the present invention provides a fastening device that is compact in design, ensures the watch's water resistance, and prevents any accidental disassembly.

[0070] The present invention can also ensure that the perfect orientation of the component locked in its operating position is maintained.

[0071] This invention offers many advantages:

[0072] - From the first relative angular position between the back cover and the middle piece, where waterproofing is ensured, for example, once the seal is compressed, in the mechanism according to the invention, there is a wide range of relative angular values ​​between the back cover and the middle piece, where multiple degrees of waterproofing are guaranteed, for example, which is important compared to the standard screw-on back cover in the case of the middle piece-back cover assembly, where loosening by a few degrees results in a loss of waterproofing, requiring cleaning and replacement of the gasket. According to the invention, waterproofing is only possible if, during disassembly, after passing through the last notch, rotation continues and the back cover 2 begins to detach from the middle piece 1 (which corresponds to the separation snap);

[0073] - The back cover is closed by a series of notches with a wide range of closing torque, which is both sufficient and acceptable for this installation. This is especially true because the number of protrusions distributed in the notches is multiplied, giving the operator a sense of gradually tightening to increase the closing torque until the desired position, known as the closed position, is reached. This desired position is also quite easy to perceive.

[0074] - Opening safety is enhanced by two factors: the operator needs to provide significant active energy to pass through a notch, and to pass through multiple notches in succession, before any loss of waterproof performance occurs.

Claims

1. A fastening device (100) for fastening a back cover on an intermediate piece of a watch, the back cover (2) having a shoulder (20) forming a cover plate (21) arranged to cover completely or partially the intermediate piece (1) and a body (22) arranged to rest in the intermediate piece (1), the fastening device comprising a ring (3) mounted between the back cover (2) and the intermediate piece (1) and integral with the intermediate piece (1) and at least one pin (4) integral with the back cover and arranged to cooperate with the ring and the intermediate piece, characterized in that the ring (3) comprising at least one recess (5) arranged to cooperate with the pin (4), the pin (4) being able to slide in the recess (5) between a first position, called insertion position, in which the back cover (2) is free, and a second position, called locking position, in which the back cover (2) is locked and angularly positioned relative to the intermediate piece (1), the recess (5) comprising at least one tab (55) to create a hard point and increase the torque during passage of the pin (4) by the tab (55).

2. The fastening device (100) for fastening a back cover on an intermediate piece of a wristwatch according to claim 1, characterized in that, the pin (4) being mounted on the back cover (2), the pin (4) having a body (42), a head (41) and a foot (43), the diameter of the body and the foot of the pin (4) being smaller than the diameter of the head.

3. Fastening device (100) for fastening a rear cover on an intermediate piece of a watch according to claim 1 or 2, characterized in that the intermediate piece (1) comprising a shoulder (10) for receiving the ring (3), the shoulder (10) of the intermediate piece (1) having at least one hole (13) to fix the ring to the intermediate piece via a fastener.

4. Fastening device (100) for fastening a back cover on an intermediate piece of a watch according to claim 2 or 3, characterized in that, the intermediate piece (1) comprising at least one hollow (15) arranged to cooperate with the head (41) of the pin, the head (41) of the pin (4) sliding within the hollow (15).

5. Fastening device (100) for fastening a back cover on an intermediate piece of a watch according to any one of the preceding claims, characterized in that, the ring (3) being made of a resiliently deformable material, such as polyoxymethylene, polyurethane, polymer-based material or elastomer material.

6. The fastening device (100) for fastening a back cover on an intermediate piece of a watch according to any one of claims 1 to 5, characterized in that, the pin (4) being made of metal or metal alloy.

7. The fastening device (100) for fastening a back cover on an intermediate piece of a watch according to any one of claims 1 to 6, characterized in that, the recess (5) extending according to one radius of the ring (3) and being through so that the pin (4) slides through the recess (5).

8. The fastening device (100) according to any one of claims 1 to 7, characterized in that the recess (5) comprising a first end (51) and a second end (52) and two walls (53) whose distance is equal to the diameter of the body (42) of the pin so as to guide and axially retain the pin.

9. The fastening device (100) according to claim 8, characterized in that the first end (51) forming a space for inserting the pin (4), the second end (52) forming a stop and retaining the pin in place.

10. The fastening device (100) according to claim 8 or 9, characterized in that the first end (51) having similar dimensions to the head of the pin (4) and the second end (52) having similar dimensions to the body (42) of the pin.

11. The fastening device (100) according to any one of claims 8 to 10, characterized in that the tab (55) being formed on one of the two walls (53) of the recess (5).

12. The fastening device (100) according to any one of claims 1 to 11, characterized in that the recess (5) comprising a plurality of tabs (55), the distance between each tab (55) being equal.

13. The fastening device (100) according to any one of claims 1 to 11, characterized in that The recess (5) comprises a plurality of tabs (55), the distance between each tab (55) being gradually decreasing.

14. The fastening device (100) according to any one of claims 1 to 13, characterized in that The fastening device comprises at least three pins (4) angularly distributed on the back cover and arranged at regular intervals.

15. A timepiece, characterized in that, The timepiece comprises a fastening device (100) according to any one of claims 1 to 14.

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