Abstract:
A fastening apparatus for fastening to a spherical stud affixed to a workpiece, the fastening apparatus removable from the stud with an unlatching tool, and the fastening apparatus comprises: an inner sleeve, which can splay out in the radial direction and can be slid over the stud; an outer sleeve axially slidable over the inner sleeve into a fastening position; and a latching device for releasably joining the outer sleeve to the inner sleeve in the fastening position, the latching device including a latching tongue which engages a latching shoulder in the fastening position, thus forming a latched connection; and wherein the fastening apparatus further comprises a tool access for insertion of the unlatching tool operable to disengage the latching tongue from the latching shoulder.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority from German Patent Application No. DE 102012003337.0, filed on Feb. 17, 2012, the disclosure of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to a fastening apparatus for fastening to a spherical stud, in particular a ball stud, having an inner sleeve, which can splay out in the radial direction and can be slid onto the stud, and having an outer sleeve, which can be slid over the inner sleeve in an axial direction into a fastening position, the outer sleeve being releasably fastenable to the inner sleeve in the fastening position by means of a latching device. 
         [0003]    A fastening apparatus of this type is known from document DE 32 32 926 C2 and can be used to fasten component parts. The spherical stud can be fixed to one of the component parts. At least one further component part can be fixed to the first component part by means of the fastening of the fastening apparatus to the spherical stud. 
         [0004]    In the known fastening apparatus described above, the inner sleeve is formed as a collet which is designed to engage, from behind, an end part of the stud, said end part being undercut in the direction of fitting. The outer sleeve is formed as a locking part which can be fitted onto the collet. At the front end parts of the locking part and of the collet, cooperating latching means are provided which are formed as circumferential latching ribs and latching grooves. In one variant, the latching means can be designed so as to be releasable. It is not possible to achieve high retaining forces in this variant. In a further variant, the latching means thus have flanks which are so steep that the latched connection to be achieved is unreleasable. In this case, high retaining forces can be achieved. However, fastening apparatuses in this variant can only be disassembled in a destructive manner. 
       BREIF DESCRIPTION OF THE INVENTION 
       [0005]    On this basis, the object of the invention is to provide an improved fastening apparatus with which high retaining forces of a fastening arrangement formed therewith can be achieved and which can still be disassembled without destruction. 
         [0006]    This object is achieved with the fastening apparatus described in the introduction in that the latching device has at least one latching tongue which engages, from behind, a latching shoulder in the fastening position, thus forming a latched connection which is secured against release, at least one tool access portion being provided on the outer sleeve and/or on the inner sleeve, a tool for releasing the latched connection being guidable through said tool access portion. 
         [0007]    The latched connection is consequently formed by the cooperation between at least one latching tongue and a corresponding latching shoulder. Due to the steepness of their flanks, the latching tongue and/or the latching shoulder are formed in such a way that it is possible to form a latched connection secured against release. The latching tongue and/or the latching shoulder preferably do not extend over the entire circumference of the fastening apparatus. The latching tongue and/or the latching shoulder should preferably extend over an angular range of less than 90°, in particular less than 60°, preferably less than 45°. 
         [0008]    The ability of the inner sleeve to splay out radially can preferably be implemented by introducing at least one axial slit into the inner sleeve, said axial slit preferably extending over at least 60% of the axial length of the inner sleeve. 
         [0009]    The inner sleeve and the outer sleeve can be provided as separate component parts. Furthermore, it may be possible to pre-assemble the inner sleeve and the outer sleeve, for example a further latching recess being provided for preassembly, in which the latching tongue can engage. 
         [0010]    The inner sleeve and outer sleeve are particularly preferably provided in one piece however, the inner sleeve and the outer sleeve being axially offset with respect to one another and being connected in an axially small region of overlap via a connecting portion which can be separated, in particular by applying an axial force between the inner sleeve and the outer sleeve. 
         [0011]    It is advantageous if the fastening apparatus is formed in one part or integrally in the pre-assembled state. 
         [0012]    High retaining forces can be achieved as a result of the latched connection, which is established in the fastening position between the latching tongue and the latching shoulder. It is still possible, via the tool access portion, to release the latched connection so as to disassemble the fastening apparatus, in particular to detach the outer sleeve from the inner sleeve, the inner sleeve and the outer sleeve not being damaged at all or substantially during this process. 
         [0013]    For example, a screwdriver or a similar tool may be used as a tool in this instance and is guided through the tool access portion and bends the latching tongue away radially so as to release the latched connection. 
         [0014]    The fastening apparatus preferably has two latching tongues which are diametrically opposed in the radial direction and two latching shoulders which are accordingly diametrically opposed. A tool for releasing the latched connection preferably has two tool tips which are preferably introduced at the same time into suitable tool access portions so as to simultaneously force the two latching tongues away and so as to simultaneously release the two latched connections formed thereby. 
         [0015]    The fastening apparatus is preferably formed in such a way that the extent to which the inner sleeve can be splayed out in the radial direction is restricted when the outer sleeve is slid over the inner sleeve so as to thus establish a positive connection in the axial direction between the spherical stud and the inner sleeve. A positive connection in the axial direction between the inner sleeve and the outer sleeve is also established by the latched connection, and therefore high retaining forces can be achieved. 
         [0016]    The inner sleeve and/or the outer sleeve are preferably formed of a plastics material and are preferably produced by an injection moulding method. In the case of a one-part fastening apparatus, the separable connecting portion between the outer sleeve and the inner sleeve may be formed by one or more thin webs between the inner sleeve and the outer sleeve. 
         [0017]    The object is thus achieved completely. 
         [0018]    According to a particularly preferred embodiment, the latching tongue is formed on the inner sleeve and/or the latching shoulder is formed on the outer sleeve. 
         [0019]    In this case it is advantageous if, in a relaxed position, the latching tongue can extend beyond the outer circumference of the inner sleeve so that it is relatively easy to slide the outer sleeve over the inner sleeve and to thus press the latching tongue radially inwardly until it ultimately engages, from behind, a latching shoulder on the inner circumference of the outer sleeve. In this embodiment a tool access portion can also be formed in a relatively simple manner, in particular by a central opening in the outer sleeve. 
         [0020]    According to a further preferred embodiment, the tool access portion has an axial recess on an inner circumference portion of the outer sleeve. 
         [0021]    A tool can thus be guided through the axial recess and into the region of the latched connection. 
         [0022]    According to a particularly preferred embodiment, the axial recess extends from one axial end of the outer sleeve (in particular an upper end) to the latching shoulder, which is preferably formed on the inner circumference of the outer sleeve. 
         [0023]    The outer sleeve and the fastening apparatus formed therewith can thus be formed in a structurally simple manner. 
         [0024]    According to a further preferred embodiment, the tool access portion has a radial recess on the outer circumference of the latching tongue. 
         [0025]    It is thus possible, in particular in combination with an axial recess on the inner circumference of the outer sleeve, to guide a tool towards the latched connection. Owing to a recess of this type, the latching tongue can also be grasped securely so as to be pressed back and so as to thus release the latched connection. 
         [0026]    According to a further embodiment, the latching tongue is formed on the outer sleeve and/or the latching shoulder is formed on the inner sleeve. 
         [0027]    In particular, it is advantageous in this variant if the tool access portion has an axial recess in the inner sleeve. 
         [0028]    The outer sleeve is preferably connected to a fastening portion. The fastening portion may have an annular collar portion extending radially outwardly with respect to the outer circumference of the outer sleeve in order to fix a planar second component part, such as a cladding part or a carpet portion, to a planar first component part, to which a spherical stud is fixed. 
         [0029]    According to a further preferred embodiment, the fastening portion has a lower part and an upper part, which are interconnected by a hinge. 
         [0030]    In this embodiment it is possible to provide receptacles for elongate objects between the lower part and the upper part. The outer sleeve is preferably a component part of the lower part. In this case, a recess may likewise be provided in the upper part so as to introduce therethrough a tool for releasing the latched connection. 
         [0031]    It is generally preferred to introduce a tool into the outer sleeve via an axial central opening. If necessary, the central opening may be closed by a removable plug or the like. 
         [0032]    According to a further embodiment, the tool access portion may also have a radial recess in the outer sleeve. This may be advantageous in terms of structure if the outer circumference of the outer sleeve is accessible, radially outwardly, in the fastening position. 
         [0033]    According to a further, all in all preferred, embodiment, the inner sleeve and the outer sleeve can be interconnected in a non-rotational manner by means of an anti-twist protection device. 
         [0034]    It can thus be ensured that the outer sleeve can only be slid axially onto the inner sleeve in one specific relative rotary position. In this one position, the latching tongue is oriented with the latching shoulder in the direction of rotation. In any case, the latched connection is consequently produced when the outer sleeve is slid on axially. 
         [0035]    The anti-twist protection device is preferably formed in such a way that the inner sleeve and outer sleeve cannot, under any circumstance, be inserted into one another in a rotary position other than the predetermined rotary position, so as to thus prevent incorrect assembly. 
         [0036]    The anti-twist protection device is preferably formed by a first anti-twist protection portion on the outer sleeve and by a second anti-twist portion on the inner sleeve, at least one of the two anti-twist protection portions extending in the axial direction. 
         [0037]    A fastening arrangement can be formed by means of the fastening apparatus, a first and second component part being fixed to one another in said fastening arrangement and the spherical stud being fixed to one of the component parts. 
         [0038]    A spherical stud is preferably to be understood to mean a rotationally symmetrical stud. This may be smooth at its outer circumference, or furrowed or the like. The spherical stud may be produced from a metal material so as to join the stud to a metal first component part, for example by means of stud welding. However, the stud may also be produced from a plastics material, in which case the first component part may likewise be produced from plastics material. Different joining methods, such as stud welding, bonding or thermowelding, are suitable for joining the stud to the first component part. 
         [0039]    In the present case, a spherical stud is also understood to mean any type of stud which has a greater diameter in a centre region compared to a region adjacent to a joining face, with which the stud is joined to a first component part, in such a way that a radial undercut is provided between the centre region and the first component part. The spherical stud may be spherical or partly spherical in longitudinal section, but may also be shaped elliptically in longitudinal section or have an angular shape, such as a T-stud, which has a narrow shaft portion and a head portion of greater diameter which is grasped by a receptacle in the inner sleeve. In the latter case, the spherical receptacle may also be angular in longitudinal section. 
         [0040]    The fastening apparatus is preferably used in the field of body construction of motor vehicles, for example to fasten cladding parts to bodywork portions or to fasten elongate second component parts to bodywork portions, the spherical stud preferably being joined to the bodywork portion. 
         [0041]    It is understood that the features described above and those yet to be explained hereinafter can not only be used in the respective combinations disclosed, but can also be used in other combinations or alone, without departing from the scope of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE VIEW OF THE DRAWINGS 
         [0042]    Exemplary embodiments of the invention are illustrated in the drawing and will be explained in greater detail in the description below. In the drawing: 
           [0043]      FIG. 1  shows a perspective view of a first embodiment of a fastening apparatus according to the invention in a pre-assembled position; 
           [0044]      FIG. 2  shows a longitudinal sectional view through a fastening arrangement with the fastening apparatus of  FIG. 1  in the pre-assembled position; 
           [0045]      FIG. 3  shows the fastening arrangement of  FIG. 2  in the fastening position; 
           [0046]      FIG. 4  shows a half sectional view of a further embodiment of a fastening apparatus according to the invention; and 
           [0047]      FIG. 5  shows a perspective view of a further embodiment of a fastening apparatus according to the invention in a pre-assembled position. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0048]    A first embodiment of a fastening apparatus according to the invention is illustrated in  FIG. 1  and is denoted generally by  10 . 
         [0049]    The fastening apparatus  10  has an inner sleeve  12  and an outer sleeve  14 , which are arranged concentrically with respect to a longitudinal axis  16 . 
         [0050]    At its axial end, the inner sleeve  12  comprises a spherical receptacle  18  for a spherical member, such as a spherical stud, in particular a ball stud. The spherical receptacle  18  is formed in such a way that the inner circumference of the inner sleeve  12  is smaller in the region of this axial end  19  than in a (centre) portion  21  spaced axially therefrom. The inner sleeve  12  further has at least one, in the present case two, slits  20 , which are diametrically opposed in the radial direction and which extend from the aforementioned axial end. The hollow semi-cylindrical portions  13  thus formed can be expanded resiliently with respect to one another in the radial direction owing to the longitudinal slits  20 . 
         [0051]    The inner sleeve  12  further comprises at least one, in the present case two, latching tongues  22 , which are radially diametrically opposed and protrude radially in the relaxed state with respect to an outer circumference  24  of the inner sleeve  12 . The latching tongues  22  can be deflected radially inwardly in such a way that the outer sleeve  14  can be slid over the inner sleeve  12 . For this purpose, the latching tongues  22  may each comprise a bevel  26  on their radial outer side so as to facilitate the sliding-on of the outer sleeve  14 . 
         [0052]    At an axial end remote from the inner sleeve  12 , the outer sleeve  14  has a fastening portion  30  for fastening a component part. In the present case, the fastening portion  30  is formed by an annular disc-like collar, which protrudes in the radial direction with respect to an outer circumference (not described in greater detail) of the outer sleeve  14 . 
         [0053]    The inner sleeve  12  and the outer sleeve  14  can be provided as separate component parts. However, the inner sleeve  12  and the outer sleeve  14  are preferably pre-assembled together so as to enable easier handling of the fastening apparatus  10 . In the present case, the inner sleeve  12  and the outer sleeve  14  are interconnected by a separable connecting portion  32 . The inner sleeve  12  and the outer sleeve  14  are preferably produced from plastics material in this instance, more specifically as a single element which is preferably produced in an injection moulding method. The connecting portion  32  can be formed by a circumferential, thin, separable web  33 , or by a single individual web  33  or a plurality of individual webs  33  distributed over the circumference and interconnecting the inner sleeve  12  and the outer sleeve  14 . 
         [0054]    One or more radial recesses  34  can also be provided at the outer circumference  15  of the outer sleeve  14  and, for example, may perform the function of an anti-twist protection and/or may be used for attachment of a tool. For example, the radial recesses  34  may be used for positioning in an automatic assembly machine, in particular if the outer part  14  and the inner part  12  are produced separately and are pre-assembled together retroactively in an automated manner. 
         [0055]      FIG. 1  also shows a first anti-twist protection portion denoted by  36  and is formed in the region of the inner circumference  17  of the outer sleeve  14  in the form of a protrusion  36  which is approximately trapezoid in cross-section in the present case. A second anti-twist protection portion  38  is also formed on the outer circumference  11  of the inner sleeve  12  and is formed in the present case as an elongate groove  38  in which the first anti-twist protection portion  36  engages. The elongate groove forming the second anti-twist protection portion  38  is preferably aligned with the slit  20 . It is generally possible for only one anti-twist protection device to be distributed over the circumference. However, two anti-twist protection devices of this type are preferably provided, each having first anti-twist protection portions  36 ,  38 , which are diametrically opposed. For example, in  FIG. 1  a further elongate groove  38 ′ is diametrically opposed with respect to the elongate groove  38  forming the second anti-twist protection portion and is aligned with the opposed slit  20 . 
         [0056]    The protrusion forming the first anti-twist protection portion  36  can preferably also perform the function of the separable connection  32  and web  33 . For example, the inner sleeve  12  and the outer sleeve  14  can be interconnected via one or two such protrusions, the protrusion being separated at its radially inward end when the outer sleeve  14  is slid onto the inner sleeve  12 . The protrusion can thus perform the function of the first anti-twist protection portion  36  when the outer sleeve  14  is subsequently slid onto the inner sleeve  12 . As a result of the anti-twist protection device thus established, the outer sleeve  14  can only be slid onto the inner sleeve  12  in one specific relative rotary position, thus ensuring that the respective latching tongues  22  are aligned with the latching shoulders  50 . 
         [0057]    The operating principle of the fastening apparatus  10  of  FIG. 1  and a method for producing a fastening arrangement will now be explained with reference to  FIGS. 2 and 3 .  FIG. 2  shows such a fastening arrangement  40  in a pre-assembled position A. 
         [0058]    The fastening arrangement  40  comprises a first component part  42  which is formed, for example, as a planar component part such as a bodywork sheet. A spherical stud in the form of a ball stud  44  is joined to a surface of the first component part  42 , for example by a stud welding method, by a bonding method or by another joining method. 
         [0059]    A second component part  46  is placed on the same side of the first component part  42  and may likewise be formed as a planar component part, for example in the form of a cladding element or the like. The second component part  46  has a through bore  47  which is continuous and is preferably circular in cross-section. The second component part  46  is placed on the first component part  42  in such a way that the stud  44  lies within the bore  47 , preferably concentrically therewith. A radially protruding portion (key)  48  may optionally be formed on the inner circumference of the recess  47  and, for example, may engage with the radial recess  34  so as to achieve anti-twist protection in a fastening position. 
         [0060]    In  FIG. 2 , which shows a longitudinal section through the fastening apparatus  10  of  FIG. 1 , it can be seen that at least one latching shoulder  50  is provided on the inner circumference  17  of the outer sleeve  14 , the number of latching shoulders  50  corresponding to the number of latching tongues  22 . In the preassembled position A shown in  FIG. 2 , the latching shoulders  50  are aligned with the latching tongues  22  in plan view. 
         [0061]    The outer sleeve  14  has an axially continuous central opening  52 . 
         [0062]    In order to establish the pre-assembled position A shown in  FIG. 2 , the fastening apparatus  10  is placed over the ball stud  44  and then an axial pressure is exerted onto the connecting apparatus  10  towards the first component part  42 . The inner sleeve  12  is thus splayed out radially in the region of the spherical receptacle  18  and then closes again resiliently around the ball stud  44  radially, as illustrated in  FIG. 2 . The end portion  19  of the spherical receptacle  18  engages (undersuts), from behind, a lower portion of the ball stud  44 . To produce a fastening position B, as illustrated in  FIG. 3 , pressure is further exerted into the outer sleeve  14 . The pre-assembled position A of the fastening apparatus  10  is thus released, and in particular the web  33  is broken and separable connecting portion  32  is separated so that the outer sleeve  14  is slid over the inner sleeve  12  in the axial direction, whilst the latching tongues  22  are deflected radially inwardly until they finally spring back resiliently and engage the latching shoulders  50  from behind, as illustrated in  FIG. 3 . A lower portion of the outer sleeve  14  engages around portion  19  of the inner sleeve  12 , in which the spherical receptacle  18  is formed. As a result of this circumferential engagement, the inner sleeve  12  is consequently prevented from splaying out in this region  19 . As a result of the undercut by portion  19  of the spherical receptacle  18  at the ball stud  44 , a positive and/or non-positive connection between the ball stud  44  and the inner sleeve  12  in the axial direction is consequently established. Owing to the latched connection  53 , which is established by the latching of the latching tongues  22  behind the latching shoulders  50 , a positive connection between the inner sleeve  12  and the outer sleeve  14  is also established, and therefore the fastening apparatus  10  is fitted to the ball stud  14  in the fastening position B shown in  FIG. 3  with a high retaining force. The second component part  46 , which is not illustrated in  FIG. 3  for reasons of clarity, is consequently fixed axially between the first component part  42  and the fastening portion  30  in the form of the annular disc-like collar, high retaining forces being provided by the fastening apparatus  10  as a result of the above-described connection between the stud pin  44 , inner sleeve  12  and outer sleeve  14 . 
         [0063]    In addition, as discussed below, the latched connection  53  can also be released again so as to thus disassemble the fastening apparatus  10  with no damage at all, or no considerable damage. 
         [0064]    In the present case, the outer sleeve  14  has at least one axial recess  54  on its inner circumference, it being possible to attach a tool via said recess so as to release the latched connection  53 . The axial recess  54  extends from the outer axial end of the outer sleeve  14 , down to the respective latching shoulder  50 . 
         [0065]    In addition or alternatively to this, the latching tongues  22  can be provided on their outer face with a radial recess  56 , as shown in  FIG. 3 . In both cases a tool access portion  58  is formed, it being possible to introduce a tool via the axial recess  54  and/or the radial recess  56  so as to deflect the latching tongues  22  radially so as to thus release the latched connection  53 . In the present case, a special tool for this could have two axial pin-like prolongations which are introduced simultaneously into the diametrically opposed tool access portions  58  so as to press together both latching tongues  22  at the same time and consequently release the latched connections  53 . 
         [0066]    As soon as the latched connection(s)  53  has/have been released, the outer sleeve  14  can be removed from the inner sleeve  12 . The inner sleeve can then also be removed from the ball stud  44  since the inner sleeve  12  can splay out again in the region of the receptacle  18 . 
         [0067]    With the parts disassembled in this manner, assembly can take place again, for example once the second component part  46  has been replaced, the inner sleeve  12  first being placed over the ball stud  44  and the outer sleeve  14  then being positioned over the inner sleeve  12  and then slid thereon axially, as in the above-described method, too. 
         [0068]    To release the latched connection  53  shown in  FIG. 3 , it is alternatively also possible to provide on the outer sleeve  14  a radial recess in the form of an opening  60  which lies at the height of the latched tongue  22  and is illustrated in FIG.  3  by dashed lines. An embodiment of this type is suitable if access to the outer circumference of the fastening apparatus  10  is possible in the fastening position B. 
         [0069]    Further embodiments of fastening apparatuses are described in  FIGS. 4 and 5  below and correspond generally to the fastening apparatus  10  of  FIGS. 1 to 3  in terms of structure and operating principle. Like elements are therefore denoted by like reference signs. The main differences will be explained hereinafter. 
         [0070]    In the case of the fastening apparatus  10 ′ shown in  FIG. 4 , the outer sleeve  14 ′ is provided at one axial end with at least one radially deflectable latching tongue  22 ′. A latching shoulder  50 ′ is formed accordingly at one axial end of the inner sleeve  12 ′, the latching tongue  22 ′ engaging in said latching shoulder in the fastening position B. It is understood that the latching tongue  22 ′ and the latching shoulder  50 ′ should be designed in such a way that sufficient circumferential forces can still be exerted by the outer sleeve  14 ′ so as to prevent the inner sleeve  12 ′ from splaying out in the fastening position. In this case, the inner sleeve  12 ′ may have an axial recess  62  for example, via which a tool can be introduced so as to release a latched connection produced by the latching tongue  22 ′ and the latching shoulder  50 ′. The corresponding tool access portion is denoted by  58 ′ in  FIG. 4 .  FIG. 4  further shows that, in this case, a further latching recess  50 ″ can be provided on the outer circumference of the inner sleeve  12 ′ so as to establish a pre-assembled position A between the outer sleeve  14 ′ and the inner sleeve  12 ′. It is understood that the inner sleeve  12 ′ and the outer sleeve  14 ′ can be interconnected by a separable connecting portion, as described above. 
         [0071]    The fastening apparatus  10 ″ shown in  FIG. 5  basically differs from the fastening apparatus  10  of  FIGS. 1 to 3  in that the outer sleeve  14  is connected to another fastening portion  30 ′. In the case of the fastening apparatus  10 ″, the fastening portion  30 ′ comprises a lower part, which extends transverse to the longitudinal axis and which may be right-angled for example in plan view, and a correspondingly shaped upper part  68 . The lower part  66  and the upper part  68  are interconnected at one of their ends via a hinge  70 , for example in the form of an integral hinge. The outer sleeve  14  is formed by the lower part  66  in this case. The upper part  68  has a central opening  52 , via which a tool can be introduced to release the latched connection. 
         [0072]    To achieve the fastening position, the lower part  66  and the upper part  68  are opened via the hinge  70 , and the lower part  66  is pressed onto the inner sleeve  12  by the outer sleeve  40  integrated in said lower part. The upper part  68  can then be folded down onto the lower part  66 , one or more receptacles for elongate objects being formed between the lower part  66  and the upper part  68 . In the present case, a first receptacle  72  is formed on one side of the longitudinal axis  16 , and a second receptacle  74  is formed on the other side of the longitudinal axis. The upper part  68  can be locked to the lower part  66  by means of a catch  76  (not described in greater detail). 
         [0073]    Although exemplary embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.