CONNECTING DEVICE BETWEEN THE CASE FRAME AND THE ARM OF A WRISTWATCH

Description

Technical Field

[0001] Of In general, the invention relates to a method for attaching a horn to a case middle of a watch, a case middle-horn connection device and a case middle-horn assembly. Technological background

[0002] THE Document CH 708815 relates to a covering element for a case middle of a wristwatch. The covering element is in the form of a separate cover plate fixed to the case middle of the wristwatch and which at least partially covers a connection area between a strand of a bracelet and the case middle of the watch.

[0003] THEDocument EP 0466655 relates to a watch case and device for attaching a bracelet to the watch case. The case middle has one or two recesses arranged to receive the end of each bracelet strand. The bracelet ends are held by attachment means, consisting of claws or hollows, corresponding to notches or protrusions arranged near the ends of the bracelet strands, and which are arranged on extensions of the case back or on intermediate parts secured to the case back or the case middle.

[0004] THEDocument EP 0197416 relates to an assembly consisting of a watch case element and a bracelet comprising at least one strand. The strand is made of a first thermoplastic plastic material. The case element is made of a second thermoplastic plastic material having a melting temperature higher than the melting temperature of the first plastic material. The case element comprises a part surrounding at least one end of the strand and being integral with this end. Also known from document GB 933969 is a reversible caseband-lug connection device for a watch. General description of the invention

[0005] Afirst aspect of the invention relates to a caseband-attachment (hereinafter caseband-lug) connection device for a watch, comprising an attachment to at least one lug having a first connector and a caseband having a second connector, the first connector being configured to cooperate with the second connector to fix the lug to the caseband, in which: ∘ the first connector comprises a tab with a recess; ∘ the second connector comprises a groove with an undercut portion, the undercut portion being configured to fit into the recess of the tab; and ∘ the middle and the horn are configured to be made integral when the undercut portion of the second connector is fitted into the recess of the tab of the first connector.

[0006] By "a groove with an undercut part" is meant a groove whose shape prevents direct demolding of solid material filling, even partially, the undercut part of it.

[0007] By "the case and the attachment are configured to be made integral" means that the attachment is configured to be irreversibly connected, by contact, to the case. "Irreversible connection" means any connection that requires the destruction of the structure of the connectors to separate the case from the attachment.

[0008] It will be appreciated that such a device makes it easy to connect a case middle and a fastener comprising at least one horn of a watch. Indeed, it is sufficient to apply compression between the case middle and the fastener so that the undercut portion of the second connector is housed in the recess of the tab of the first connector. In this way, and thanks to the undercut portion, removal by a force opposite to the compression is impossible: the fastener and the case middle are integral.

[0009] According to a preferred embodiment, the tongue is configured to elastically deform upon insertion into the groove, the tongue and the undercut portion being configured such that the tongue substantially returns to its rest position, preferably returns to its rest position, when the undercut portion is housed in the recess of the tongue.

[0010] Preferably, the groove extends over a length L. The length L may be in the range from 10% to 90%, preferably in the range from 40% to 80%, more preferably in the range from 50% to 70%, most preferably in the range from 60% to 70% of the length over which the tab is configured to elastically deform upon insertion into the groove 1< . It will be appreciated that in this way, the two connectors are firmly connected. In addition, this configuration mitigates the risk of detachment and / or damage to the connectors when applying a moment of force to one and / or the other of the two connectors. 1< It may be necessary to modify according to the applications.

[0011] Theregroove may include a recessed portion over which the tongue is configured to flex elastically upon insertion of the tongue into the groove. In this way the elastic deformation (i.e., elastic bending) of the tongue is forced and accompanied by the recessed portion until the undercut portion of the second connector seats in the recess of the tongue of the first connector.

[0012] Preferably, the recess is through.

[0013] According to one embodiment, the first connector comprises a tenon and the second connector comprises a mortise. The mortise is configured to guide the tenon when the first connector of the horn is brought into contact with the second connector of the middle part. According to a preferred embodiment, the first connector comprises two or more tenons and the second connector comprises two or more mortises. The mortises are configured to guide the tenons when the first connector of the horn is brought into contact with the second connector of the middle part. It will be appreciated that the presence of one or more tenons and one or more mortises makes it possible to guide the insertion of the first connector into the second connector. The presence of several tenons and mortises makes it possible to mitigate the risk of incorrect insertion when, e.g., a force torque is applied to the first and / or second connectors.

[0014] THEsecond connector preferably comprises one or more support portions for the tab of the first connector to limit elastic deformations of the tab when the undercut portion is seated in the recess of the tab. The one or more support portions may, e.g., sterically (i.e., geometrically) limit elastic deformations of the tab.

[0015] The tongue is preferably made of steel.

[0016] The remainder of the fastener (other than the tab) is preferably made of a different material than the tab. In one embodiment, the remainder of the fastener is molded around the tab, with the tab projecting from the fastener. The molding is preferably made from a plastic material. The edges of the tab may be trapped in the molding of the remainder of the fastener.

[0017] The second connector can be machined, preferably the case is machined. The case is preferably made of steel.

[0018] A second aspect of the invention relates to a fastening method comprising a caseband-lug connection device according to the first aspect of the invention. The method comprises inserting the first connector of the fastener into the second connector of the caseband in such a way that the undercut portion is housed in the recess of the tab.

[0019] A third aspect of the invention relates to a case-horn assembly obtained by the fixing method according to the second aspect of the invention. Brief description of the drawings

[0020] Other features and characteristics of the invention will emerge from the detailed description of certain advantageous embodiments presented below, by way of illustration, with reference to the appended drawings which show: Fig. 1 :a perspective view of a case-horn assembly according to one embodiment of the invention; Fig. 2 : a perspective view of a case and a fastener according to one embodiment of the invention; Fig. 3 : a perspective view of a case and a fastener according to one embodiment of the invention; Fig. 4 : a perspective view of a case and a fastener according to one embodiment of the invention; Fig. 5 : a cross-section of a case and a fastener according to one embodiment of the invention; Fig. 6 : a cross-section of a case middle and a fastener during insertion of the horn into the case middle according to an embodiment of the invention; and Fig. 7 : a cross-section of a case-horn assembly according to one embodiment of the invention.

[0021] The reader's attention is drawn to the fact that the drawings are not to scale. Furthermore, for reasons of clarity, the proportions between height, length and / or width may not be correctly represented. Last but not least, the spaces, recesses, between the connectors brought into contact may be larger or smaller than in an actual implementation of the invention. Detailed description of an embodiment of the invention

[0022] With reference to the Fig. 1, a caseband 2 - attachment to at least one horn 4 (hereinafter caseband-horn assembly) according to an embodiment of the invention is described. Caseband 2 is an element of a watch case (partially shown) serving to protect the watch movement e.g. from dust, humidity, shocks, etc. It is the middle part of the watch case which receives the watch movement. According to the embodiment described, caseband 2 is circular. However, other shapes are suitable, such as e.g. a square shape, a rectangular shape, an ellipsoidal shape, etc. Caseband 2 defines a main plane P located halfway up it.

[0023] The attachment to at least one horn 4 makes it possible to attach a bracelet to the middle 2. In the embodiment illustrated in Fig. 1, the attachment 4 comprises four horns 4a each provided with holes 6 aligned transversely to the longitudinal direction of a bracelet (not shown), the horns 4a being arranged to attach the bracelet using, for example, a bar passing through the holes 6. It is obvious that other means of fixing the bracelet to the attachment are suitable. Furthermore, the shape, length and width and number of horns 4a may vary depending on the type of watch.

[0024] THE Figs. 2-5 show the attachment 4 and the middle 2 when they are not secured, according to a preferred embodiment of the invention. The attachment 4 comprises a first connector 8 and the middle 2 comprises a second connector 10. The first connector 8 is configured to cooperate with the second connector 10 to fix the attachment 4 on the middle 2.

[0025] The first connector 8 comprises a circular inner surface 12, perpendicular to the main plane P, configured to be in direct contact with the middle 2 when the middle 2 and the horn 4 are secured. The first connector 8 comprises two tenons 14 and a tab 16, all projecting from the circular inner surface 10 inwards (i.e. towards the middle 2).

[0026] Generally, the length of an element (e.g. of the tongue, of the through recess) is defined as the (Euclidean) distance between the two most distant points of the element in a plane collinear with the plane P.

[0027] The tongue 16, made of steel, comprises a through recess 18 over a length L' of the tongue 16. The length L' is in the range from 70% to 95%, preferably from 70% to 90%, more preferably from 70% to 80% of the length of the tongue 16.

[0028] The remainder of the fastener 4 (i.e. other than the tab) is overmolded to the tab 16. In this way, the tab 16 is made integral with the remainder of the fastener 4. The remainder of the fastener 4 is made of plastic.

[0029] More particularly, the tab 16 comprises two curved edges meeting at their ends. The overmolding is carried out in such a way that the radially outermost edge is trapped in the molding and the radially innermost edge is free and projects inwardly. The space between the two edges remaining free after overmolding corresponds to the through recess 18. It will be appreciated that other techniques can be used to trap the tab 16 in the remainder of the fastener 4.

[0030] The radially innermost edge 38 of the fastener 4, projecting inwards, comprises a radially outer abutment planar surface 19. The planar surface 19 is perpendicular to the plane P and extends over a length L" in the range from 20% to 80%, preferably 30% to 70%, more preferably 25% to 40% of the length of the tab 16.

[0031] The state (and position) of tab 16 shown in Figs. 2-5 is its state (and position) of rest.

[0032] The tenons 14 are arranged symmetrically on either side of the attachment 4 and have a cylindrical shape, the base of the cylinder being perpendicular to the main plane P. According to other embodiments, the tenons 14 may have other shapes, e.g. parallelepiped, conical, etc.

[0033] The middle part 2 comprises a second connector 10 configured to cooperate with the first connector 8 of the attachment 4 to fix the attachment 4 on the middle part 2. In particular, the second connector comprises an oblong curved surface 20 radially set back relative to the radially outer surface of the middle part 2. The oblong curved surface 20 is configured to be placed in direct contact with the circular inner surface 12 of the attachment 4. The second connector 10 comprises a groove 22, two mortises 24 and two support parts 25 for the tongue, all forming a depression relative to the oblong curved surface 20.

[0034] The groove includes an undercut portion 26. The undercut portion 26 extends over a length L. The length L may be substantially equal to the length L" of the planar surface 19. The ratio of the length L to the length L" is in a range from 0.7 to 1.3, preferably in a range from 0.8 to 1.2 and more preferably in a range from 0.95 to 1.15.

[0035] The undercut portion 26 comprises a radially inner planar abutment surface 28, substantially perpendicular to the plane P, preferably with a re-entrant angle of the order of 5°. Furthermore, the undercut portion 26 also comprises a recess 30 delimited by the radially inner planar abutment surface 28 and a radially outer planar abutment surface 32. The radially outer planar abutment surface 32 is perpendicular to the plane P. The ratio between the height H of the radially outer surface 32 and the height H' of the tongue is between 0.3 and 1.5, preferably between 0.35 and 0.5.

[0036] On the other hand, the groove comprises a relief portion 34 having a relief planar surface 36. The relief planar surface makes an angle α with respect to the plane P. The angle α is in a range from 10° to 45°, preferably from 15° to 40°, more preferably from 20° to 35°.

[0037] The groove also comprises two support portions 25 for the tongue. The two support portions 25 are arranged laterally, symmetrically, at the edges of the groove. The ratio between the height H" of the support portions 25 and the height H' of the tongue is in the range from 0.8 to 1.5 and preferably from 1 to 1.15. In addition, the length L (4)< of each support portion 25 is in the range from 2.5% to 20%, preferably from 5% to 15%, more preferably from 7% to 13% of the length of the tongue.

[0038] The mortises 24 are arranged symmetrically on either side of the second connector 10 (laterally substantially at the edges of the second connector 10). The mortises 26 have a cylindrical shape whose base of the cylinder is perpendicular to the main plane P. According to other embodiments, the mortises 26 may have other shapes, e.g. parallelepiped, conical, etc.

[0039] There Fig. 6 is a sectional view showing the insertion of the fastener 4 into the caseband 2 as they begin to engage. The projecting edge 38 deforms elastically upon contact with the flat undercut surface 36. More particularly, the projecting edge 38 is flexed by the flat undercut surface 36. The remainder of the caseband and the ends of the edge 38 are held in place by the support portions 25 and the tenons 14 housed in the mortises 24 (not shown - see e.g. Figs. 1-5 ). In this context, it is noted that the tenons 14 and the tongue 16 (substantially) simultaneously contact the mortises 24 and the parts 25, 34, respectively. It follows that the mortises and the support parts guide the tenons and the ends of the projecting edge when the first connector of the horn is brought into contact with the second connector.

[0040] There Fig. 7is a sectional view showing the insertion of the attachment 4 into the middle 2 when they are securely engaged. The edge has returned to its rest position by insertion into the recess 30 of the undercut portion 26. This insertion has taken place when the edge has passed the undercut surface 36 (in particular when the radially outer flat stop surface 19 has passed the radially outer flat stop surface 32 of the undercut portion 26). According to another embodiment, the edge may only substantially return to its rest position. This may, for example, be the case when the recess is not through and the undercut portion does not allow the edge to return to its rest position.

[0041] The radially outer surface 32 of the undercut portion 26 is in direct contact with the radially outer flat stop surface 19 of the projecting edge 38. The middle 2 and the attachment 4 are thus made integral and form a middle-horn assembly. Indeed, the application of a force opposite to that applied for the insertion of the attachment 4 into the middle 2 does not allow the latter to be separated.

[0042] In addition, the circular inner surface 12 of the attachment and the oblong curved surface 20 of the middle 2 are in direct contact, where appropriate with a clearance of the order of 1 / 10 mm when the middle and the attachment are secured.

[0043] The ratio between the height H" of the support parts 25 and the height H' of the tongue being substantially the same, the possible elastic deformations of the projecting edge 38 are significantly reduced compared to the possible deformations when the projecting edge is not inserted into the connector 10 of the caseband 2. Indeed, the support parts 25 sterically limit the elastic deformation of the edge 38, in particular in the event of force applied to the attachment in a direction perpendicular to the dial. It is therefore much more difficult to separate the attachment from the caseband than to secure them.

[0044] While particular embodiments have just been described in detail, those skilled in the art will appreciate that various modifications and alternatives thereto may be developed in light of the overall teaching provided by the present disclosure of the invention. Accordingly, the specific arrangements and / or methods described herein are intended to be given solely by way of illustration, without the intention of limiting the scope of the invention as defined by the appended claims.

Claims

1. A case middle / attachment piece (hereinafter 'case middle / horn') connection device for a watch, comprising an attachment piece (4) including at least one horn and having a first connector (8), and a case middle (2) having a second connector (10), the first connector being configured to cooperate with the second connector to attach the attachment piece to the case middle (2), wherein: the first connector (8) comprises a tongue (16) with a recess (18); the second connector (10) comprises a groove (22) with an undercut portion (26), the undercut portion being configured to lodge inside the recess (18) of the tongue (16); and the case middle (2) and the attachment piece (4) are configured to be made integral when the undercut portion (26) of the second connector (10) is lodged inside the recess (18) of the tongue of the first connector, and wherein the case middle (2) and the attachment piece (4) are made inseparably integral with one another by a bond that requires the connectors (8, 10) to be destroyed in order to allow separation of the case middle from the attachment piece.

2. The case middle / horn connection device claimed in claim 1, wherein the tongue (16) has a rest position, and wherein the tongue (16) is configured to deform elastically when inserted into the groove (22), the tongue (16) and the undercut portion (26) being configured such that the tongue (16) returns substantially to its rest position when the undercut portion (26) lodges in the recess (18) of the tongue.

3. The case middle / horn connection device claimed in claim 2, wherein the groove (22) also comprises an undercut portion on which the tongue (16) is configured to bend elastically when the tongue is inserted into the groove (22).

4. The case middle / horn connection device according to any of claims 1 to 3, wherein the recess (18) is a through recess.

5. The case middle / horn connection device according to any of claims 1 to 4, wherein the first connector (8) comprises a tenon (14) and the second connector (10) comprises a mortise (24), the mortise being configured to guide the tenon when the first connector of the attachment piece is placed in contact with the second connector of the case middle.

6. The case middle / horn connection device according to claim 5, wherein the first connector (8) comprises two or more tenons (14) and the second connector (10) comprises two or more mortises, the mortises being configured to guide the tenons when the first connector of the attachment piece is placed in contact with the second connector of the case middle.

7. The case middle / horn connection device according to any of claims 1 to 6, wherein the second connector comprises one or more support parts (25) for the tongue of the first connector in order to limit the elastic deformations of the tongue when the undercut portion (26) is lodged in the recess (18) of the tongue (16).

8. The case middle / horn connection device according to any of claims 1 to 7, wherein the tongue (16) is made of steel.

9. The case middle / horn connection device according to any of claims 1 to 8, wherein the attachment piece is moulded around the tongue, the moulding preferably being made from a plastic material.

10. The case middle / horn connection device according to any of claims 1 to 9, wherein the case middle (2) is machined, preferably the second connector (10) is machined.

11. A method of attachment comprising a case middle / horn connection device according to any of claims 1 to 10, the method comprising the insertion of the first connector (8) of the attachment piece into the second connector (10) of the case middle such that the undercut portion (26) lodges inside the recess (18) of the tongue (16).

12. Case middle / horn assembly obtained by the attachment method according to claim 11.