(19)
(11)EP 3 115 019 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
06.05.2020 Bulletin 2020/19

(21)Application number: 15759038.1

(22)Date of filing:  02.02.2015
(51)Int. Cl.: 
A61C 13/263  (2006.01)
A61C 8/00  (2006.01)
A61C 13/267  (2006.01)
(86)International application number:
PCT/KR2015/001053
(87)International publication number:
WO 2015/133733 (11.09.2015 Gazette  2015/36)

(54)

DENTURE FIXING ATTACHMENT

ZAHNERSATZBEFESTIGUNG

ATTACHE DE FIXATION DE PROTHÈSE DENTAIRE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 06.03.2014 KR 20140026568

(43)Date of publication of application:
11.01.2017 Bulletin 2017/02

(73)Proprietor: Wang, Je Won
Daejeon 305-510 (KR)

(72)Inventor:
  • Wang, Je Won
    Daejeon 305-510 (KR)

(74)Representative: Lavoix 
Bayerstrasse 83
80335 München
80335 München (DE)


(56)References cited: : 
JP-A- H11 244 308
JP-B2- 2 557 047
US-A- 5 194 000
US-A- 5 890 902
US-A1- 2010 075 277
JP-A- 2005 528 164
KR-Y1- 200 471 489
US-A- 5 417 570
US-A- 6 102 702
US-A1- 2010 105 005
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    [Technical Field]



    [0001] The present invention relates to a denture-fixing attachment used to fix a denture after a dental implant treatment and, more particularly, to a denture-fixing attachment, which has an economic effect due to a simple structure and consequent improvement in productivity, highly efficient workability due to a simplified assembly process, and increased stability in use due to the secure maintenance of engagement force for a long time period and consequent prevention of unexpected release of engagement.

    [Background Art]



    [0002] Conventionally, when a tooth is pulled out, a false tooth is positioned in place of the pulled-out tooth, or a dental bridge treatment, in which surrounding teeth are employed as pillars and a crown is positioned in place of the pulled-out tooth, is performed, thereby maintaining a patient's oral health.

    [0003] However, this treatment causes problems in which false teeth or artificial teeth resulting from the bridge treatment are weak in chewing foods, exert a bad influence on surrounding teeth, and may even damage other teeth.

    [0004] Accordingly, implant treatment has been recently introduced and is being widely administered, and is characterized in that an artificial tooth root is formed, and an artificial tooth, produced so as to appear highly similar to a real tooth, is coupled to the artificial tooth root, so that a patient obtains an effect of using the real tooth.

    [0005] Such an implant treatment is one dental medical treatment for securely fastening an attachment, to which a false tooth (an artificial tooth) is coupled, to an alveolar bone, and is typically carried out according to the following procedures: an implant recess having female threads formed in an inner peripheral surface thereof, to which a fixture having male threads formed in an outer peripheral surface thereof is screwed, is formed for implantation of the fixture in an alveolar bone having no tooth, the fixture is screwed to the implant recess, an abutment having a joint coupled thereto, to which a false tooth (an artificial tooth) is secured, is engaged with female threads formed in the fixture, a neighboring gum is sutured, and a false tooth (an artificial tooth) is coupled to the top portion of the joint.

    [0006] In the above implant treatment process, the fixture implanted in the alveolar bone serves as a tooth root, and the attachment including the abutment and the joint is a connection component for integrating the fixture with the false tooth (the artificial tooth).

    [0007] That is, as described above, the fixture and the attachment constitute an implant structure for securely fixing the false tooth (the artificial tooth) at the correct position, and are preferably formed of a metal material such as, particularly, titanium, having superior physical/chemical strength.

    [0008] Although a typical prosthetic appliance or a typical false tooth damages surrounding teeth or bones over time, a false tooth (an artificial tooth) fixed by an implant treatment performs the function of the original tooth and has the same shape as the original tooth, and does not decay, so the implanted false tooth can be semi-permanently used.

    [0009] Korean Patent Registration No. 10-0925766 discloses an attachment for use in implant treatment, which is applied to a dental implant and is milled or prepped into a shape suitable for accepting a dental prosthetic, and in which a recess extends axially upwardly from an axial bottom end of a metallic appendage and is shaped to fit over an O-ball or an O-ring receiver abutment of a dental implant, an abutment including a coupling protrusion is provided, the coupling protrusion is repositioned in a coupling recess formed in an upper portion of a fixture, the abutment is fastened to the fixture using a screw, a prosthesis including a screw hole is provided, and dental cement is put between the abutment and the prosthesis to bond the prosthesis to the abutment.

    [0010] In addition, Korean Patent Registration No. 10-1042372 discloses an integral-type implant, which includes a screw portion provided at a lower portion of the implant and having threads formed in the outer surface of the screw portion so as to be rotated about one axis and implanted into a dentary bone, and an abutment provided at an upper portion of the implant, the abutment being integrally formed with the screw portion and being capable of being embedded in a gum covering the dentary bone and of being covered with a cap. The abutment includes a gingival level portion, which is brought into contact with the gum, and a protrusion portion, which is provided at an upper portion of the gingival level portion and to which the cap is removably attached. The protrusion portion has a coupling recess extending downward from the top surface thereof in an axial direction, and the coupling recess has a sectional shape that may engage with a driver used to rotate the implant.

    [0011] In addition, Korean Patent Publication No. 10-2007-0112075 discloses a separable-type abutment for a dental implant, which is fixed to a fixture implanted into an alveolar bone to support a dental prosthesis. The abutment includes a lower member fixed to the fixture, an upper member fixed to the dental prosthesis, and a coupling structure for removably coupling the upper member to the lower member.

    [0012] However, the above-described conventional attachments have a problem in that a denture cannot be coupled to a denture-fixing attachment when several fixtures implanted into a patient are not arranged parallel to each other, thereby requiring another operation for implanting the fixtures parallel to each other or connection work using additional parts.

    [0013] To solve this problem, Korean Utility Model Publication No. 20-2013-0005969 (entitled: DENTURE-FIXING ATTACHMENT FREELY ADJUSTABLE IN ANGLE AND POSITION) has been recently devised.

    [0014] The attachment, as disclosed in the above document, is configured such that, when a denture is connected to a fixture implanted in a slanted direction, the denture can be connected to the fixture without additional parts, thereby enabling a doctor to comfortably and easily perform an implant treatment for a patient. Documents US 2010/075277 A1 and US 5 417 570 A disclose additional devices belonging to the closest prior art.

    [Disclosure]


    [Technical Problem]



    [0015] However, although the conventional denture-fixing attachment, as described above, is capable of fixing a denture to a fixture implanted in a slanted direction, it has a problem of being uneconomical in that productivity and workability are deteriorated due to the complicated structure and the inconvenient assembly process, and a problem of being unstable due to possibility of release of the assembly when used for a long time period.

    [0016] The present invention is devised to solve the above problems, and an object of the present invention is to provide a denture-fixing attachment, which has an economic benefit due to its simple structure and consequent improvement in productivity, highly efficient workability due to a simplified assembly process, and increased stability in use due to the secure maintenance of engagement force for a long time period and consequent prevention of unexpected release of engagement.

    [Technical Solution]



    [0017] The object of the present invention can be achieved by providing a denture-fixing attachment for freely connecting a denture to a fixture implanted into an alveolar bone in a slanted direction by adjusting the fixing angle of the denture with respect to the fixture, the denture-fixing attachment including a rod-shaped joint member having an upper end for supporting the denture fixed thereto, and an abutment having a coupling portion formed in the outer surface of the lower portion thereof so as to be coupled to a fixture recess formed in the fixture, and a receiving portion formed in the upper portion thereof so as to receive the lower portion of the joint member therein, the receiving portion of the abutment including a receiving recess for receiving the lower end of the joint member inserted thereinto, and a stop protruding portion provided in the receiving portion above the receiving recess and having a guide groove for guiding the coupling movement of a locking protruding portion, protruding outward from the lower end of the joint member, fitted thereinto, characterized in that the guide groove (9) is formed to have a L shape in an inner peripheral surface of the stop protruding portion (10) and the locking protruding portion (8) is configured so as to be fitted into the guide groove in a push-turn-push engagement manner.

    [0018] The upper end and the lower end of the joint member may have hemispherical-shaped surfaces, and the joint member may further include a connection portion between the upper end and the lower end, the connection portion being formed to have a rod shape having a smaller diameter than the diameter of the upper end.

    [Advantageous Effects]



    [0019] The denture-fixing attachment according to the present invention constituted as above has an economic effect due to a simple structure and consequent improvement of productivity because the joint member, to which a denture is fixed, and the abutment, to which the joint member is pivotably coupled, have a structure capable of being assembled in a fitting manner, highly efficient workability due to a simplified assembly process, which can be achieved merely by fitting work, and increased stability in use due to structural stability in that the receiving portion for receiving the joint member is formed to have an integral structure and due to the consequent prevention of unexpected release of engagement of a denture for a long time period.

    [Description of Drawings]



    [0020] 

    FIG. 1 is a schematic exemplary sectional view showing a denture-fixing attachment not forming part of the invention.

    FIG. 2 is a schematic exemplary sectional view showing the assembly state of the denture-fixing attachment according to the embodiment.

    FIG. 3 is an exemplary partially enlarged sectional view showing the operational state of the denture-fixing attachment according to the embodiment.

    FIG. 4 is a schematic exemplary sectional view showing the in-use state of the denture-fixing attachment according to the embodiment.

    FIG. 5 is an exemplary partially enlarged sectional view showing the denture-fixing attachment according to one embodiment not forming part of the present invention.

    FIG. 6 is an exemplary partially enlarged sectional view showing an abutment applied to a denture-fixing attachment according to the embodiment of the present invention.

    1: Attachment 2: Alveolar Bone

    3: Fixture 4: Denture

    5: Joint Member 6: Abutment

    7: Receiving Recess 8: Locking Protruding Portion

    9: Guide Groove 10: Stop Protruding Portion

    11: Lower End of Joint Member 12: Upper End of Joint Member

    13: Connection Portion of Joint Member


    [Best Mode]



    [0021] Hereinafter, a denture-fixing attachment according to a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

    [0022] The present invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. In the drawings, the shapes of components are exaggerated for clarity of illustration. In the drawings, the same or similar elements are denoted by the same reference numerals even though they are depicted in different drawings. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

    [0023] FIGS. 2 to 4 are views showing a denture-fixing attachment according to one embodiment forming part of the present invention. A denture-fixing attachment 1 according to the embodiment is configured to adjust the angle at which a denture 4 is fixed to a fixture 3 implanted into an alveolar bone 2, thereby freely connecting the denture 4 to the fixture 3 implanted in a slanted direction.

    [0024] That is, an implant recess used to implant the fixture 3 is formed in the alveolar bone 2 using a tool such as, for example, a drill, the fixture 3 is implanted into the implant recess, and the attachment is fixed to the fixture 3 and serves as a connection component for connecting the denture 4 to the fixture 3.

    [0025] The implant recess has female threads formed therein, and the fixture 3 has male threads formed in the outer peripheral surface thereof to mesh with the female threads, so that the fixture 3 is screwed to the implant recess.

    [0026] The denture-fixing attachment 1 according to the embodiment includes a rod-shaped joint member 5, to an upper end of which the denture 4 is fixed, and an abutment 6 having a coupling portion formed in the outer surface of a lower portion thereof, which is coupled to a fixture recess formed in the fixture 3, and a receiving portion formed in an upper portion thereof, in which a lower portion of the joint member 5 is received.

    [0027] That is, the denture-fixing attachment includes the abutment 6, which is coupled to the fixture 3, and the joint member 5, which is pivotably and rotatably jointed to the abutment 6 and is connected with the denture 4, so that the denture 3 is fixed to the alveolar bone 2.

    [0028] Preferably, the aforementioned fixture recess is embodied as a spiral nut recess, and the coupling portion of the abutment 6 is embodied as male threads, which mesh with the fixture recess, so that the abutment 6 is screwed to the fixture 3.

    [0029] In the above-described denture-fixing attachment 1 according to the embodiment, the receiving portion of the abutment 6 includes a receiving recess 7, into which the lower end 11 of the joint member 5 is inserted, and a stop protruding portion 10, which is provided in the receiving portion above the receiving recess 7 and has a guide groove 9, into which a locking protruding portion 8, protruding outward from the lower end 11 of the joint member 5, is fitted and which guides the coupling movement of the locking protruding portion 8.

    [0030] That is, the locking protruding portion 8 of the joint member 5 is inserted into the guide groove 9 in the stop protruding portion 10 and is guided thereby, and the lower end 11 of the joint member 5 is received in the receiving recess 7, so that the lower end 11 of the joint member 5 freely pivots and rotates with respect to the inner peripheral surfaces of the receiving recess 7 and the stop protruding portion 10, thereby adjusting the angle formed by the upper end 12 of the joint member 5 and the abutment 6.

    [0031] Therefore, even when the fixture 3 is implanted into the alveolar bone 2 in a slanted direction, the denture 4 is capable of being stably connected and fixed to the fixture 3.

    [0032] In addition, the lower end 11 of the joint member 5 received in the receiving recess 7 is in contact with the stop protruding portion 10 provided above the receiving recess 7 so as to be prevented from being unexpectedly separated from the receiving recess 7, thereby enhancing stability without concern as to the release of the engagement of the denture 4 for a long time period.

    [0033] That is, since the stop protruding portion 10, which functions to prevent the lower end 11 of the joint member 5 from being separated from the receiving recess 7, is integrally formed with the receiving recess 7, not only additional parts but also additional fastening elements are unnecessary, which enhances structural strength and enables stable long-term use.

    [0034] In the above-described denture-fixing attachment 1 according to the embodiment, at least a predetermined portion of the guide groove 9 is preferably formed to extend in a horizontal direction in the inner peripheral surface of the stop protruding portion 10.

    [0035] Accordingly, in the state in which the lower end 11 of the joint member 5 is guided along the inner peripheral surface of the stop protruding portion 10 and is received in the receiving recess 7, the locking protruding portion 8 is in contact with the horizontally extending portion of the guide groove 9 and is prevented from being separated from the receiving recess 7.

    [0036] That is, the guide groove 9 is formed to have an "L" shape or, as illustrated in FIG. 6, to have a "

    " shape in the inner peripheral surface of the stop protruding portion 10, and in this case, the locking protruding portion 8 protrudes from the outer peripheral surface of the lower end of the joint member 5, and is fitted into the guide groove (for example, in a push-turn-push engagement manner).

    [0037] In an alternative not forming part of the invention, the locking protruding portion 8 may be preferably formed to have an annular shape around the outer peripheral surface of the lower end of the joint member 5, so that the locking protruding portion 8 is screwed to the spiral guide groove 9.

    [0038] Therefore, the annular-shaped locking protruding portion 8 provided at the lower end 11 of the joint member 5 is moved from the opening of the receiving portion to the receiving recess 7 through the screw-engagement with the spiral guide groove 9, and is prevented from being unexpectedly separated from the receiving recess 7.

    [0039] Preferably, the bottom surface of the receiving recess 7 has a hemispherical shape, and the lower end 11 of the joint member 5 also has a hemispherical shape corresponding to the hemispherical-shaped receiving recess 7 so as to come into close contact with the bottom surface of the receiving recess 7, so that the lower end 11 of the joint member 5 easily pivots and rotates with respect to the bottom surface of the receiving recess 7.

    [0040] More preferably, in the denture-fixing attachment 1 according to the embodiment constituted as above, both the upper end 12 and the lower end 11 of the joint member 5 have curved surfaces, more precisely hemispherical-shaped surfaces, and a connection portion 13 between the upper end 12 and the lower end 11 is formed to have a rod shape, which has a smaller diameter than the diameter of the upper end 12.

    [0041] Accordingly, even when the upper end 12 of the joint member 5 is coupled to a portion of the denture 4 at a certain inclination angle, the maximum possible area for close contact between the upper end 12 of the joint member 5 and the denture 4 can be secured.

    [0042] Further, since the angle at which the joint member 5 can pivot with respect to the receiving portion is decided depending on the diameter of the connection portion 13, a user may select a connection portion having a suitable shape, and may use the same.

    [0043] That is, as illustrated in FIGS. 3 and 5, the smaller the diameter H or h of the connection portion 13, the larger the pivot range, and accordingly a user may simply select a joint member having a suitable shape for the dental treatment, and assemble and use the same.

    [0044] The operational effects of the denture-fixing attachment according to the embodiment constituted as above will now be explained in detail.

    [0045] When a dental treatment of fixing the denture 4 is performed using the denture-fixing attachment 1 according to the embodiment, as illustrated in FIG. 4, the fixture 3 is first implanted into the alveolar bone 2 as described above.

    [0046] Subsequently, the joint member 5 is fastened to the receiving portion of the abutment 6 in a screw-engagement manner so that the lower end 11 of the joint member 5 is inserted and received in the receiving recess 7, and the attachment 1, formed through the assembly of the abutment 6 and the joint member 5, is fastened to the fixture recess of the fixture 3.

    [0047] As such, when the attachment 1 is coupled to the fixture 3, a fixing portion of the denture 4 is fixedly coupled to the upper end 12 of the joint member 5, thereby completing the denture-fixing treatment.

    [0048] Depending on the treatment conditions, for example, in the case in which the denture 4 is connected to the fixture 3 implanted into the alveolar bone 2 in a slanted direction, the treatment can be carried out after the angle of the joint member 5 with respect to the receiving recess 7 is adjusted by pivoting the joint member 5.

    [0049] As described above, the denture-fixing attachment according to the embodiment has an economic effect due to the simple structure of the abutment to which the joint member is pivotably coupled, highly efficient workability due to a simplified assembly process, and increased stability in long-term use due to structural stability in that the receiving recess and the stop protruding portion, which constitute the receiving portion, are integrally formed.

    [0050] The embodiment of the present invention as described above is only illustrative, and it will be understood by those skilled in the art that various modifications and other equivalent exemplary embodiments may be made. Therefore, it will be understood that the present invention is not limited only to the forms mentioned in the detailed description. Accordingly, the true technical scope of the present invention should be defined by the appended claims. In addition, it is to be understood that the present invention includes all modifications, equivalents, and substitutions which fall within the scope of the present invention as defined by the appended claims.

    [Industrial Applicability]



    [0051] The present invention relates to a denture-fixing attachment used to fix a denture after a dental implant treatment and, more particularly, to a denture-fixing attachment, which has an economic effect due to a simple structure and consequent improvement of productivity, highly efficient workability due to a simplified assembly process, and increased stability in use due to the secure maintenance of engagement force for a long time period and the consequent prevention of unexpected release of engagement, and therefore, the present invention has industrial applicability.


    Claims

    1. A denture-fixing attachment (1) for freely connecting a denture (4) to a fixture (3) implanted into an alveolar bone in a slanted direction by adjusting a fixing angle of the denture with respect to the fixture, the denture-fixing attachment comprising:

    a rod-shaped joint member (5) having an upper end for supporting the denture fixed thereto; and

    an abutment (6) having a coupling portion formed in an outer surface of a lower portion thereof so as to be coupled to a fixture recess formed in the fixture, and a receiving portion formed in an upper portion thereof so as to receive a lower portion of the joint member therein,

    wherein the receiving portion of the abutment includes a receiving recess (7) for receiving a lower end (11) of the joint member inserted thereinto, and a stop protruding portion (10) provided in the receiving portion above the receiving recess and having a guide groove (9) for guiding coupling movement of a locking protruding portion (8), protruding outwardly from the lower end of the joint member, fitted thereinto,

    characterized in that the guide groove (9) is formed to have a L shape in an inner peripheral surface of the stop protruding portion (10) and the locking protruding portion (8) is configured so as to be fitted into the guide groove in a push-turn-push engagement manner.


     
    2. The denture-fixing attachment according to claim 1, wherein the upper end (12) and the lower end (11) of the joint member (5) have hemispherical-shaped surfaces, and
    the joint member further includes a connection portion (13) between the upper end and the lower end, the connection portion being formed to have a rod shape having a smaller diameter than a diameter of the upper end.
     


    Ansprüche

    1. Ein Prothesenfixierteil (1) zur freien Verbindung einer Zahnprothese (4) mit einem in einem Alveolarknochen implantierten Befestigungsteil (3) in schräger Richtung durch Anpassen eines Befestigungswinkels der Zahnprothese in Bezug auf das Befestigungsteil, wobei das Prothesenfixierteil umfasst:

    ein stangenförmiges Gelenkelement (5) mit einem oberen Ende zur Unterstützung der darauf befestigten Zahnprothese; und

    eine Stütze (6) mit einem Kopplungsabschnitt, der in einer Außenfläche eines unteren Abschnitts davon derart ausgebildet ist, dass er mit einer im Befestigungsteil ausgebildeten Aussparung gekoppelt werden kann, und einem in einem oberen Abschnitt davon ausgebildeten Aufnahmeabschnitt zur Aufnahme eines unteren Abschnitts des Gelenkelements,

    wobei der Aufnahmeabschnitt der Stütze umfasst: eine Aufnahmeaussparung (7) zur Aufnahme eines unteren Endes (11) des darin aufgenommenen Gelenkelements, und einen Anschlagvorsprung (10), der im Aufnahmeabschnitt oberhalb der Aufnahmeaussparung ausgebildet ist und eine Führungsrille (9) zur Führung der Kopplungsbewegung eines vom unteren Ende des Gelenkelements nach außen hin hervorstehenden, darauf befestigten Verriegelungsvorsprungs (8) aufweist,

    dadurch gekennzeichnet, dass die Führungsrille (9) derart ausgebildet ist, dass sie in einer Innenumfangsfläche des Anschlagvorsprungs (10) L-förmig ist, und der Verriegelungsvorsprung (8) derart eingerichtet ist, dass er durch einen Druck-Dreh-Druck-Eingriffsmechanismus in die Führungsrille eingeführt wird.


     
    2. Das Prothesenfixierteil nach Anspruch 1, wobei das obere Ende (12) und das untere Ende (11) des Gelenkelements (5) halbkugelförmige Oberflächen aufweisen, und
    das Gelenkelement ferner einen Verbindungsabschnitt (13) zwischen dem oberen Ende und dem unteren Ende umfasst, wobei der Verbindungsabschnitt die Form einer Stange aufweist, welche einen kleineren Durchmesser aufweist als das obere Ende.
     


    Revendications

    1. Attache de fixation de prothèse dentaire (1) pour raccorder librement une prothèse dentaire (4) à une fixation (3) implantée dans un os alvéolaire dans une direction inclinée en ajustant un angle de fixation de la prothèse dentaire par rapport à la fixation, l'attache de fixation de prothèse dentaire comprenant :

    un élément de joint en forme de tige (5) ayant une extrémité supérieure pour supporter la prothèse dentaire fixée à ce dernier ; et

    une butée (6) ayant une partie de couplage formée dans une surface externe de sa partie inférieure afin d'être couplée à un évidement de fixation formé dans la fixation, et une partie de réception formée dans sa partie supérieure afin de recevoir une partie inférieure de l'élément de joint à l'intérieur de cette dernière,

    dans laquelle la partie de réception de la butée comprend un évidement de réception (7) pour recevoir une extrémité inférieure (11) de l'élément de joint inséré à l'intérieur de cette dernière, et une partie en saillie de butée (10) prévue dans la partie de réception au-dessus de l'évidement de réception et ayant une rainure de guidage (9) pour guider le mouvement de couplage de la partie en saillie de verrouillage (8), faisant saillie vers l'extérieur à partir de l'extrémité inférieure de l'élément de joint, monté dans cette dernière,

    caractérisée en ce que la rainure de guidage (9) est formée pour avoir une forme de L dans une surface périphérique interne de la partie en saillie de butée (10) et la partie en saillie de verrouillage (8) est configurée pour être montée dans la rainure de guidage par mise en prise par poussée - rotation - poussée.


     
    2. Attache de fixation de prothèse dentaire selon la revendication 1, dans laquelle l'extrémité supérieure (12) et l'extrémité inférieure (11) de l'élément de joint (5) ont des surfaces de forme hémisphérique, et
    l'élément de joint comprend en outre une partie de raccordement (13) entre l'extrémité supérieure et l'extrémité inférieure, la partie de raccordement étant formée pour avoir une forme de tige ayant un diamètre inférieur à un diamètre de l'extrémité supérieure.
     




    Drawing












    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description