Patent Publication Number: US-2023161293-A1

Title: Method for manufacturing gasket seals from this assembly

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to European Patent Application No. 21210354.3 filed Nov. 25, 2021, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD OF THE INVENTION 
     The invention falls within the field of microengineering, and is particularly advantageously applied in the field of horology. 
     More specifically, the invention relates to a method for manufacturing gasket seals from this assembly. 
     TECHNOLOGICAL BACKGROUND 
     Gasket seals intended to be arranged in watch cases are produced from cutting, generally by machining with cutting tools, for example by milling or by turning, an assembly of tubes joined together in a collinear manner. 
     The tubes have a cylindrical shape and include a transverse section defining the shape of the gasket obtained after machining. 
     In order to be fixed without degree of freedom in relation to one another, the tubes may be soldered at their opposite ends. For example, to this end, two tubes are bearingly arranged by one of their ends against a hot plate until their melting temperature is reached, and said ends are subsequently held against one another until cooled. 
     It is also possible, alternatively to soldering, to glue two adjoining tubes at their interface by spreading a glue layer on their respective ends and by holding them in position on a template until the glue has dried. 
     However, such solutions, in addition to having the drawback of posing difficulties of respecting collinearity tolerances, generate a bead, respectively of solder or of glue, forming a burr on the inner and outer surfaces of the assembly. 
     Alternatively, the tubes may be connected together by means of dedicated parts, such as connection sleeves, for example to be screwed, well known by the person skilled in the art. 
     Such a solution is generally long and tedious to implement, in addition to generating an additional cost by adding additional parts in the assembly. 
     SUMMARY OF THE INVENTION 
     The invention resolves the aforementioned drawbacks by proposing a solution making it possible to guarantee the collinearity of the tubes joined together, control the appearance of the outer surface of the assembly and not requiring assembly templates or additional parts other than the tubes for producing the assembly. 
     To this end, the present invention relates to a method for manufacturing gasket seals consisting in producing, through machining operations, a plurality of cuts in an assembly produced by at least two identical joined tubes, each tube extending along a longitudinal axis between two ends, the end of one tube, referred to as “first end”, having a shape complementary to the shape of the end of the other tube, referred to as “second end”, so that said first and second ends cooperate by complementarity of shape. 
     Advantageously, the assembly makes it possible to guarantee the collinearity of the tubes with one another, and thus eliminate any risk of unbalance that could be detrimental during the machining of said assembly. 
     Moreover, these features make it possible to avoid any burrs on the outer surface of the assembly. 
     Another advantage of the invention resides in the fact that it makes it possible to control the dimensions of the tubes, and thus of the assembly. 
     In particular implementations, the invention may further include one or more of the following features, taken alone or according to any technically possible combinations. 
     In particular implementations, the manufacturing method includes, before carrying out the machining operations, a preliminary step of producing the assembly wherein the tubes are obtained by moulding then joined together, so as to obtain said assembly. 
     In particular implementations, the manufacturing method includes, before carrying out the machining operations, a preliminary step wherein, for each tube, a cylindrical body is produced by extrusion and a first end is produced by moulding, then said first end is fixed to said cylindrical body, and finally the tubes thus formed are joined together so as to obtain said assembly. 
     In particular implementations, during the preliminary step, the first end is overmoulded on the cylindrical body. 
     In particular implementations, when the tubes are joined, they are screwed together, at their first and second respective opposite ends. 
     In particular implementations, when the tubes are joined, they are glued or driven together, at their first and second respective opposite ends. 
     According to another aspect, the present invention relates to a watch comprising a gasket seal obtained by implementing the method as described above, and comprising a case formed by a middle, a crystal and a back. The gasket is arranged against the middle, so as to be interposed between a back and the middle, between the crystal and the middle, or between the bezel and the middle. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Other features and advantages of the invention will become apparent upon reading the following detailed description given by way of non-limiting example, with reference to the appended drawings wherein: 
         FIG.  1    shows a sectional view of an assembly intended to be machined to produce gasket seals, said assembly comprising four joined tubes; 
         FIG.  2    shows a sectional view of a tube of the assembly of  FIG.  1   ; 
         FIG.  3    shows a sectional view of a tube according to another alternative embodiment of the invention; 
     
    
    
     It should be noted that the figures are not to scale. 
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG.  1    shows an assembly  10 , intended to be machined to produce gasket seals according to the present invention. 
     The assembly  10  includes a plurality of tubes  20 , preferably identical, joined so as to form a bar extending along a longitudinal axis combined with that of each tube  20 . 
     As illustrated in  FIGS.  2  and  3    in various alternative embodiments of tubes  20 , each tube  20  extends between a first and a second end  21  and  22  having complementary shapes, so that the first end  21  of one tube  20  cooperates by complementarity of shape with the second end  22  of another tube  20 . 
     Thus, the assembly  10  consists of a plurality of tubes  20  successively joined together by each of their first and second ends  21  and  22 , with the exception of the tubes  20  arranged at the ends of the assembly 
     The tubes  20  are fixed together without degree of freedom, for example by driving and/or by gluing at their interface. 
     The first end  21  of each tube  20  advantageously includes a post  210  extending along a longitudinal axis of the tubes  20 , from a radial surface  211  with which it forms an annular shoulder. 
     The second end  22  is formed by an axial opening  220  opening on an end surface  221  and wherein the post  210  of an adjacent tube  20  is engaged, as shown in  FIG.  1   , so that the radial surface  211  from which said post  210  extends is bearingly arranged against said end surface  221 , this contact defining the axial positioning of the two tubes  20  adjacent to one another. 
     The radial positioning of the two adjacent tubes  20  is defined by the engagement of the post  210  in the opening  220 . 
     More specifically, in the embodiment of the invention shown in  FIGS.  1  to  3   , between its first and second ends  21  and  22 , each tube  20  includes a hollow cylindrical body  23  defined between an outer surface  230  and an inner surface  231 , the opening  220  being materialised by the inner surface  231  of the second end  22 . 
     The inner surface  231  of the second end  22  may advantageously receive the possible glue layer mentioned above in the text, to increase the fixing between the two tubes  20 , so that the glue does not project beyond the outer surface  230 . 
     Alternatively, the glue layer may be applied on the outer surface of the post  210 . 
     In the preferred embodiment of the invention shown in the figures, each tube  20  is monobloc in that it is formed in one piece. 
     The cylindrical body  23  may or may not have a shape of revolution. 
     In  FIGS.  1  and  2   , the tubes  20  are blind insofar as the opening  220  only opens on their second end  22 , whereas in the alternative embodiment shown in  FIG.  3   , the tubes  20  have a through opening  220  also opening on the first end  21 . 
     Advantageously, the second end  22  may include a chamfer or a neck-moulding  222  defined between the end surface  221  and the inner surface  231  in order to facilitate the engagement of the post  210  of a tube  20  in the opening  220  of another tube  20  and thus, to facilitate the production of the assembly  10 . 
     In order to perfect the cooperation of shape between the first and the second end  21  and  22 , the first end  21  may include a chamfer or neck-moulding  212  defined between the radial surface  211  and the post  210 . The neck-moulding  212  of the first end  21  of each tube  20  is then opposite the chamfer or neck-moulding  222  of the second end  22  of the adjacent tube  20  with which said first end  21  cooperates, except for a tube  20  constituting one end of the assembly  10 ; for example the end tube  20  to the right of the assembly  10  that can be seen in  FIG.  1   . 
     In this same objective, the post  210  may comprise a chamfer or a neck-moulding  213  at its free end, as illustrated in  FIG.  3   . 
     Advantageously, the complementary shapes of the first and second ends  21  and  22  are not shapes of revolution, in order to prohibit any possible rotation between the tubes  20 . Thus, the assembly  10  is more resistant to the torsional forces particularly endured during the machining of the assembly  10 . This feature makes it possible to significantly reduce the risks of rupture of the assembly  10 , that is to say the separation of two adjacent tubes  20 , during the machining of the gaskets. 
     More specifically, the transverse sections of the posts  210  and of the openings  220  may be of polygonal shape, for example square, triangular, etc., or of curved shape, for example oval, poly-lobed, etc. 
     Alternatively, the respective first and the second ends  21  and  22  of two adjacent tubes  20  may cooperate with one another by means of a helical connection. More specifically, the posts  210  may be threaded so as to be engaged by screwing into the openings  220  that are then tapped. 
     In another embodiment of the invention not shown in the figures, for each tube  20 , the cylindrical body  23  and the post  210  may be formed independently from one another, so that the tube  20  results from the securing of a cylindrical body  23  and of a post  210 . 
     In this case, the cylindrical body  23  and the post  210  may be of different materials and may be driven and/or glued. 
     Only the portions of the tubes  20  of the assembly  10  that are outside of the interfaces between the first and second ends  21  and  22  are usable, insofar as they are intended to form, after successive transverse cutting operations of the assembly  10  by machining, the gasket seals. In other words, the portions of the assembly  10  consisting of the interfaces between the first and second ends  21  and  22  of the tubes  20  are not used and constitute rejects. 
     By way of example, each tube  20  may have a length between 20 and 80 centimetres, preferably 30 centimetres. 
     These length values of the tubes  20  are advantageous because they constitute a good compromise between a length of the tubes  20  that is too difficult to produce by moulding operation, and a length that is too short minimising the usable portions of each tube  20 . 
     As mentioned above, the method for manufacturing gasket seals consists in producing a plurality of transverse cuts in an assembly  10  by machining operations with cutting tools, particularly turning, and in particular profile-turning. The cuts may be followed by complementary machining operations, such as milling operations, in order to true the section of the gaskets obtained. 
     The length of the assembly  10  may be of a plurality of metres and is in practice only limited by machining machine constraints. 
     The manufacturing method includes, before carrying out machining operations, a preliminary step of producing the assembly  10 , wherein the tubes  20  are obtained by moulding, then joined together. 
     Alternatively, during the preliminary step, for each tube  20 , the cylindrical body  23  is produced by extrusion and the first end  21  is produced by moulding, then each first end  21  is fixed to a cylindrical body  23 , and finally, the tubes  20  thus formed are joined together. 
     More specifically, during the preliminary step, the first end  21  may be overmoulded on the cylindrical body  23 . 
     The present invention is particularly adapted to obtain gasket seals intended to be arranged against a middle of a watch case, for example interposed between a back and the middle, a crystal and the middle or a bezel and the middle. 
     By way of example, the material of the tubes  20  is a polymer, particularly a polyurethane, preferably that of the type known by the person skilled in the art under the trade name “Asutane”. 
     More generally, it should be noted that the implementations and embodiments considered above have been described by way of non-limiting examples, and that other variants are consequently possible.