Patent Abstract:
The invention relates to an elastic hinge element ( 60 ) for a spectacle frame, comprising a body ( 10 ) consisting of a housing ( 11 ) comprising a guiding area ( 12 ) and at least one cavity comprising a retaining partition, a slide ( 20 ) fitted in the housing and comprising a guided part ( 22 ), a center part and a rod, a spring ( 40 ) for returning the slide to a rest position, mounted around the rod, and a bushing ( 30 ) forming a front stop for the spring. According to the invention, the cavity comprising the retaining partition is located in the guiding area ( 12 ) and opens out therein, and the guided part ( 22 ) of the slide comprises a recess into which an elastic tab ( 32 ) of the slide extends. Advantage: creation of a short-length hinge element.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of International Application No. PCT/FR2005/000820 filed Apr. 5, 2005, which was published in the French language on Dec. 22, 2005, under International Publication No. WO 2005/121873 A1 and claims priority to French Patent Application Nos. 0404911, filed May 6, 2004 and 0405711, filed May 27, 2004, the disclosures of which are incorporated herein by reference in their entirety. 

   The present invention relates to the field of spectacles and hinges for spectacle frame, and relates more particularly to an improvement of an elastic hinge element for spectacle frame of the type described by International Application No. WO 00/68730. 
   The present invention thus relates to an elastic hinge element for spectacle frame, comprising a housing comprising a hollow longitudinal portion comprising a guiding area and at least one cavity comprising a retaining wall, a slide arranged in the hollow portion according to a longitudinal translation axis, comprising a protruding part extending outside the hollow portion, a guided part cooperating with the guiding area, a central part and a rod, a spring for returning the slide to a rest position, a compression part of the spring, coupled with the rod and forming a rear stop for the spring, and a bushing forming a front stop for the spring, comprising a body mounted around the central part of the slide and at least one elastic tab turned towards the front of the hollow portion according to a determined angle, the end of which presses on the retaining wall. 
   As a reminder, such a classic hinge element is represented in  FIG. 1A . The hinge element comprises a housing  1  in which a hollow portion  2  is made, and a slide  3  arranged in the hollow portion  2 . The hollow portion  2  comprises a guiding area  2 - 1  for guiding the slide  3  according to a longitudinal translation axis T and opens onto the front of the hinge element to form a front orifice. The slide  3 , also represented in  FIG. 1B , comprises an end  3 - 1  forming a hinge knuckle, extending outside the hollow portion  2 , a guided part  3 - 2  cooperating with the guiding area  2 - 1 , a central part  3 - 3  and a rod  3 - 4 . A spring  4  is mounted around the rod  3 - 4 , between a bushing  5  and a compression part  3 - 5  that is coupled with the end of the rod  3 - 4 . The bushing  5  comprises a body  5 - 1  slidably mounted around the rod  3 - 4  and two elastic tabs  5 - 2 ,  5 - 3  facing forwards according to a determined angle in relation to the translation axis. In the rest position shown in  FIG. 1A , the end of each elastic tab  5 - 2 ,  5 - 3  enters a cavity  6 ,  7  to come and press on a retaining wall  6 - 1 ,  7 - 1  substantially perpendicular to the translation axis. As a result, when the slide is pulled forwards, the bushing  5  is translation blocked and the spring is compressed between the mobile compression part  3 - 5  and the fixed body  5 - 1  of the bushing  5 . 
   Such a hinge element is only a few millimeters in length and is frequently used in the spectacles industry. It is generally fixed by welding or gluing onto a spectacle frame arm  8  schematically represented in  FIG. 1A . The knuckle  3 - 1  is generally linked to a hinge element coupled with the frame, such as a tenon, to obtain an arm hinge. 
   Despite the small dimensions of this hinge element, it is desired to reduce its length so as to produce ultra-compact hinges that are even more aesthetically discreet. 
   Reducing the length of the hinge element involves reducing the length of the slide. This length depends on the lengths of the four useful parts of the slide, i.e. the part forming the knuckle  3 - 1 , the guided part  3 - 2 , the central part  3 - 3 , and the rod  3 - 4  that bears the spring and the body  5 - 1  of the bushing. 
   Now, a decrease in the length of the guided part  3 - 2  beyond a determined minimal length would excessively weaken the hinge element, as this part must viably withstand forces and stresses exerted in directions perpendicular to the translation axis. To guarantee a good resistance to the off-axis loads while reducing the length of the guided part, a two-point guiding could be considered, by adding a guiding element at the rear end of the slide, for example using the compression part as additional guiding element. However, using the rear end of the slide would weaken the axis of the slide as the latter would be subject to flexion. Moreover, the compression part is generally an inexpensive element the manufacturing of which is basic, obtained for example by striking the end of the rod  3 - 4  so as to make a blister appear that translation-blocks the spring. Providing a guiding element at the rear of the slide is therefore not desirable. 
   Secondly, the length of the central part  3 - 3  of the slide is imposed by the length of the bushing  5 , which is approximately equal to the sum of the length of the body  5 - 1  of the bushing and that of the elastic tabs  5 - 2 ,  5 - 3 . The central part  3 - 3  indeed enables the retraction of the elastic tabs when the slide equipped with the bushing and the spring is introduced into the hollow portion passing through the front orifice. Now, the length of the tabs of the bushing is also subject to certain technological stresses, and cannot be excessively reduced. 
   Finally, the length of the rod  3 - 4  cannot itself be reduced below a minimal spring length, corresponding to a targeted minimal backmoving force, to which the length of the body of the bushing is added. 
   BRIEF SUMMARY OF THE INVENTION 
   Thus, the present invention aims to reduce the length of the slide of a hinge element of the type described above without reducing the length or the size of the essential elements of the hinge, i.e. the length of the guided part, the length of the bushing, and the length of the spring. 
   According to the present invention, this object is achieved by providing an elastic hinge element for a spectacle frame, comprising a housing comprising a hollow longitudinal portion comprising a guiding area and at least one cavity comprising a retaining wall, a slide arranged in the hollow portion according to a longitudinal translation axis, comprising a protruding part extending outside the hollow portion, a guided part cooperating with the guiding area, a central part and a rod, a spring for returning the slide to a rest position, a compression part for compressing the spring, coupled with the rod, forming a rear stop for the spring, and a bushing forming a front stop for the spring, comprising a body mounted around the central part of the slide and at least one elastic tab turned towards the front of the hollow portion according to a determined angle, the end of which presses on the retaining wall, in which the cavity comprising the retaining wall is situated in the guiding area and opens into the latter, and the guided part of the slide comprises at least one guiding face that comprises firstly a recess into which a portion of the elastic tab extends when the slide is in rest position, and secondly guiding edges situated along the edge of the recess. 
   According to one embodiment, the guided part comprises a recess of a size sufficient to ensure the total retraction of the elastic tab when the bushing is introduced into the hollow portion passing through the guiding area. 
   According to one embodiment, the proximal part of the elastic tab extends entirely in the guiding area and the body of the bushing abuts against the guided part of the slide. 
   According to one embodiment, the cavity comprising the retaining wall opens onto the outside of the housing. 
   According to one embodiment, the bushing has two elastic tabs, the guided part of the slide has two first guiding faces and two second guiding faces comprising two recesses receiving the elastic tabs and guiding edges situated along the edge of the recesses. 
   According to one embodiment, the guided part of the slide has in its region comprising the recess, a section substantially in the form of an “H” with the central cross of the “H”. 
   According to one embodiment, the guided part of the slide has in its region comprising the recess, a section substantially in the form of an “H” without the central cross of the “H”. 
   According to one embodiment, the recesses are made in the two narrowest faces of the guided part of the slide. 
   According to one embodiment, the recesses are made in the two widest faces of the guided part of the slide. 
   According to one embodiment, the central part of the slide is a prolongation of a rod bearing the spring. 
   The present invention also relates to a spectacle frame, comprising an elastic hinge element according to the present invention. 
   The present invention also relates to a spectacle frame arm, comprising an elastic hinge element according to the present invention. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings: 
       FIG. 1A  is a cross-section of a classic or prior art elastic hinge element; 
       FIG. 1B  is a side elevational view of a slide present in the prior art hinge element shown in  FIG. 1A ; 
       FIG. 2  is a partial cross-sectional perspective view of a hinge element according to a first preferred embodiment of the present invention; 
       FIG. 3  is a cross-section of a housing of the hinge element shown in  FIG. 2 ; 
       FIG. 4  is a perspective view of a slide present in the hinge element shown in  FIG. 2 ; 
       FIG. 5  is a perspective view of a bushing present in the hinge element shown in  FIG. 2 ; and 
       FIG. 6  is a perspective view of a slide according to an alternative embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 2  is an overall view of an elastic hinge element  60  according to the present invention, represented in rest position. The element  60  classically comprises a housing  10 , represented in a cross-section, a slide  20 , a bushing  30 , a coil spring  40 , and a compression part  50  for compressing the spring, forming a rear stop for the spring. 
   The housing  10  is represented in greater detail in  FIG. 3 , the slide  20  is represented in greater detail in  FIG. 4 , and the bushing is represented in greater detail in  FIG. 5 . Certain references in  FIGS. 3 to 5  are not reproduced in  FIG. 2 , for the sake of readability of this figure. 
   The housing  10  comprises a hollow longitudinal portion  11  receiving the slide  20  that opens onto the front of the hinge element to form a front orifice. The shape of the hollow portion is designed to be able to introduce the assembly formed by the slide, the bushing, the spring and the compression part into the hollow portion  11 , passing through the front orifice. 
   The slide  20  comprises a protruding part  21  forming a knuckle, that extends from the front orifice to the outside of the hollow portion  11 , a guided part  22 , as well as a central part  23  and a rear rod  24 , the central part  23  and the rod  24  having a smaller section than the guided part  22 . Here, the central part  23  and the rod  24  are formed by one and the same rod, of rectangular, round or polygonal section, around which the bushing  30  and the spring  40  are threaded. The protruding part  21  comprises a pierce point intended to receive a pin for connecting with a tenon (not represented). It shall be noted that the compression part, although represented in the Figure as an element distinct from the rod, can be classically formed by a blister of the end of the rod. This part is in this case part of the rod itself. 
   The hollow portion  11  comprises a guiding area  12  having guiding walls cooperating with the guided part  22  of the slide, and cavities  13 ,  14  comprising two retaining walls  15 ,  16  substantially perpendicular to the translation axis and turned towards the rear of the hollow portion  11 . The guiding walls do not necessarily cover the entire guiding area  12 , as represented for example in  FIG. 3  where it can be seen that the guiding area is obtained by piercing a cylindrical orifice and then by machining flat guiding walls in the cylindrical orifice forming sorts of rails. 
   Furthermore, the cavities  13 ,  14  are for example obtained by transversally piercing the housing  10 , such that the cavity corresponding to the introduction of the piercing tool, here the cavity  14 , opens onto the outside of the housing. 
   The bushing  30  classically comprises a body  31 , that is threaded around the central part  23  of the slide, and two elastic tabs  32 ,  33  facing forwards forming an angle “A” in relation to the translation axis of the slide. Each elastic tab comprises a proximal part  320 ,  330  linked to the body  31 , and a distal part  321 ,  331 . 
   When the slide  20 , after being equipped with the bushing  30 , with the spring  40  and with the compression part  50 , is introduced into the hollow portion  11  passing through the front orifice, the elastic tabs  32 ,  33  fold up towards the slide when the latter passes through the guiding area  12 . Once the operation performed, the elastic tabs loosen and their ends lodge in the cavities  13 ,  14 . 
   According to the present invention, the cavities  13 ,  14  are made in the guiding area  12  itself, and open onto the guiding area  12  instead of opening onto a region of the hollow portion  11  corresponding to the central part  23  of the slide, as is the case in prior art (refer to  FIG. 1A ). Again according to the present invention, the guided part  22  of the slide has two recesses  220 ,  221  each provided for receiving the proximal part  320 ,  330  of one of the elastic tabs  32 ,  33 . Thus, the body  31  of the bushing is pushed by the spring  40  against the guided part  22  of the slide, the spring being preferably substantially compressed or bordering on compression when the slide is in rest position. 
   When the slide  20  is inserted into the hollow portion  11 , and more particularly when the bushing passes through the guiding area  12 , the elastic tabs  32 ,  33  of the bushing retract into the recesses  220 ,  221 . When the rest position represented in  FIG. 2  is reached, they extend in the guiding area  12  and not in the region of the hollow portion  11  corresponding to the central part  23  of the slide, as is the case in prior art. More particularly, the proximal parts  320 ,  330  of the elastic tabs extend in the recesses  220 ,  221 , the distal parts  321 ,  331  of the elastic tabs extend in the cavities  13 ,  14 , and the ends of the elastic tabs are opposite the retaining walls  15 ,  16 . 
   When the slide is pulled forwards, the spring  40 , as it compresses, pushes the elastic tabs against the retaining walls  15 ,  16 . The latter thus translation-block the bushing  30 , the spring  40  then being compressed between the compression part  50  and the bushing  30 , and ensuring the slide returns to rest position. 
   In the hinge element structure that has just been described, the longitudinal extension of the elastic tabs  32 ,  33 , which is mathematically equal to the length of the tabs multiplied by the cosine of the angle “A”, is not taken into account to determine the length of the central part  23  of the slide and as a result to determine the total length of the slide. The length of the central part  23  of the slide only depends on the length of the body  31  of the bushing. The latter, as represented in  FIG. 5 , is here a sort of square section ring formed for example by folding a metal strip cut in the shape of π having two perpendicular tabs that form the elastic tabs. 
   Furthermore, as it can be seen in  FIG. 4 , the guided part  22  of the slide has left  22 - 1  and right  22 - 2  lateral faces that provide the right and left lateral guiding, and upper  22 - 3  and lower  22 - 4  lateral faces that provide the upper and lower lateral guiding. The recesses  220 ,  221  are made here on the faces  22 - 3 ,  22 - 4  and extend here over approximately half the length of the guided part  22 . 
   According to the present invention, the elastic tabs  32 ,  33  and the recesses  220 ,  221  are here narrower than the faces  22 - 3 ,  22 - 4  and advantageously on the edge of the recesses  220 ,  221 , narrow bands ( FIG. 4 , face  22 - 3 , bands  22 - 5 ,  22 - 6 ) remain which form sorts of rails or glides that also provide the upper and lower lateral guiding of the slide, the rear part of the guided part  22  thus having a section substantially in the shape of an H. 
   Thus, the guided part  22  has a front part that is devoid of any recess and that supports the slide in four complementary directions perpendicular to the translation axis, and a rear part bearing the recesses  220 ,  221 , that also advantageously supports the slide in the four directions. 
   Various alternatives of the present invention can be provided by those skilled in the art. In an alternative embodiment represented in  FIG. 6 , the recesses  220 ′ are made in the left  22 - 1  and right  22 - 2  lateral faces of the guided part of the slide, the width of which, corresponding to the height of the slide, is greater than the width of the upper and lower faces of the guided part. 
   In other alternative embodiments, the guided part of the slide can have a round, oval or polygonal section. The recesses receiving the proximal parts of the elastic tabs can have various shapes, for example they can have an inclined bottom corresponding to an angle of retraction of the elastic tabs when assembling the hinge element. They can also be through-hole and meet, the rear part of the guided part of the slide having in this case the shape of an “H” without the central cross of the H. Furthermore, the bushing may comprise three, or even four elastic tabs, a corresponding number of recesses then being provided in the guided part of the slide. The bushing can also comprise only one elastic tab, although a symmetrical bushing structure is better suited to a good distribution of the spring retaining forces. Secondly, although it is advantageous for the proximal parts of the elastic tabs to extend entirely in the recesses, so that the body of the bushing is in contact with the guided part of the slide and the length of the central part of the slide is minimal, providing an intermediate embodiment between prior art and the embodiment that has just been described falls within the scope of the present invention. In this embodiment, the section of the central part  23  of the slide has an enlargement translation-blocking the body of the bushing before the latter abuts against the guided part (refer for example to  FIG. 1B ). The elastic tabs thus comprise a proximal part that extends along the central part of the slide, a central part that extends in the recesses according to the present invention, and a distal part that extends in the cavities comprising the retaining walls. Thus, irrespective of the embodiment of the present invention, the cavities  13 ,  14  comprising the retaining walls are arranged in the guiding area  12  and the ends of the elastic tabs  32 ,  33  extend up to the guiding area thanks to the recesses according to the present invention. The present invention thus enables the body of the bushing to be moved as close as desired to the guided part of the slide and the total length of the hinge element to be reduced accordingly, while respecting the minimal lengths of the spring and of the guiding part that are imposed by the technological stresses and the solidity requirements of the hinge element. 
   Finally, although it was stated above that the recesses according to the present invention are formed so as to enable the elastic tabs to fully retract when the slide is introduced into the hollow portion of the housing, this feature is only required if the slide is introduced into the housing in this manner. 
   Various arrangements of a hinge element according to the present invention may be made. Although it is generally fixed onto spectacle frame arms, such a hinge element can also be mounted onto the rim of the frame, or onto a fixed arm part coupled with the frame rim. 
   It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.

Technology Classification (CPC): 6