Abstract:
The female attachment, which is made of plastics material, has a recess and at least two lugs projecting into the recess for clipping it to a stud. It includes connecting members extending between a first body and a second body and delimiting the recess, the connecting members comprising at least one rigid arm and at least two flexible strips separated from each other. The obturator includes a female attachment of the above kind and a skirt.

Description:
RELATED APPLICATIONS 
   The present application is based on, and claims priority from, French Application Number 0408468, filed Jul. 30, 2004, the disclosure of which is hereby incorporated by reference herein in its entirety. 
   FIELD OF THE INVENTION 
   The invention relates generally to female attachments of plastics material. 
   BACKGROUND OF THE INVENTION 
   There are prior art female attachments of plastics material featuring a recess and at least two lugs projecting into said recess for attaching said attachment to a stud engaged in said recess. 
   In particular, the document U.S. Pat. No. 5,098,242 discloses an attachment of the above kind that includes a body having a central opening through which the recess opens. The attachment has three projecting lugs rooted in the vicinity of the opening. 
   The end of the lugs can be deformed elastically so that the attachments can be fitted over the stud. 
   The free end of each lug is wedge-shaped and locates in the hollow of the thread on the stud. 
   In addition to the lugs, studs situated above the lugs are provided for screwing and unscrewing the stud. 
   SUMMARY OF THE INVENTION 
   The invention aims to provide a female attachment of plastics material of the above type offering the possibility of cooperating with a plurality of types of studs each having a different diameter, whilst being particularly simple and convenient to manufacture and to use. 
   To this end the invention proposes a female attachment of plastics material having a recess and at least two lugs projecting into said recess for clipping said attachment to a stud engaged in said recess, which attachment is characterized in that it comprises: 
   at a first end, a first body having a central opening, 
   at a second end, opposite said first end, a second body, and 
   connecting members extending between said first body and said second body and delimiting said recess, which is open at said first end via said central opening of said first body, said connecting members comprising at least one rigid arm and at least two flexible strips that are separated from each other, each of said strips being disposed facing one of said clipping lugs, opposite said recess, each of said lugs being connected to said first body and comprising a rigid portion having teeth adapted to engage with the thread of said stud and a toe opposite said teeth facing a respective one of said strips. 
   Accordingly, upon engaging a stud in the recess of the attachment, the lugs move apart by a distance corresponding to the diameter of the stud without being impeded by the flexible strips, with the result that the force needed to press it in may be moderate. If traction is applied to the attachment to pull it out, at least one of the strips is stretched firmly and the respective lug is held against the stud, which provides a particularly high resistance to pulling out. 
   According to features of the invention that are particularly simple and convenient to manufacture and to use: 
   the teeth comprise two adjacent wedge members adapted to engage with said thread; and/or 
   each of said lugs has a free end opposite said first body, at least one lug having its free end axially offset relative to the free end of another lug; and/or 
   each of said lugs comprises a portion forming a hinge between said rigid portion and said first body; and/or 
   said attachment comprises exactly two arms and two lugs, said arms and said lugs being disposed in a regularly alternating manner; and/or 
   said first body has a beveled rim facing said recess along said opening; and/or 
   a flange of arcuate shape connected to said second body extends from each of said arms in the direction of the opposite arm, each of said strips being connected to a respective one of said flanges. 
   The invention also proposes an obturator adapted to be fixed to a stud, characterized in that it comprises an attachment according to any preceding claim and a skirt, said attachment and said skirt comprising mutual nesting means, and, optionally: 
   said second body has a rim disposed radially relative to the connecting members and said skirt has a central orifice flanked by a projecting circular rib, said rib being abutted against said rim; and/or 
   said skirt is made of plastics material that is more flexible than that of said attachment. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     Features and advantages of the invention will emerge from the following description, which is given by way of preferred but non-limiting example and with reference to the appended drawings, in which: 
       FIG. 1  is a view in elevation of a female attachment of the invention; 
       FIG. 2  is a view of it in section taken along the line II-II in  FIG. 1 ; 
       FIG. 3  is a view of it in section taken along the line III-III in  FIG. 1 ; 
       FIG. 4  is a view of it in section taken along the line IV-IV in  FIG. 3 ; 
       FIG. 5  is a perspective view of the attachment provided with a skirt to form an obturator of the invention; 
       FIG. 6  is a view of the skirt in section in a plane passing through its axis; 
       FIG. 7  is a view in elevation of the  FIG. 5  obturator; and 
       FIGS. 8 and 9  are views in section taken along the line IV-IV in  FIG. 3  showing studs of large and small diameter, respectively. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The attachment  1  is molded in one piece from plastics material. It has a generally cylindrical structure extending between a first body, here a ring  2 , and a second body  3 . The attachment  1  includes a recess. 
   The ring  2  includes a circular central opening  4  through which a stud can pass towards the recess. 
   The ring  2  has an exterior surface  5  extending around the opening  4 . Starting from this exterior surface  5 , the ring  2  has two beveled edges, one leading to the opening  4  and facilitating the passage of the stud and the other leading to the outside and facilitating the insertion of the attachment  1  into another member such as a skirt. 
   The ring  2  includes two parallel and diametrally opposed lateral flats  7 . 
   There are two upstanding transverse rigid arms  10  of substantially parallelepiped shape on an annular interior surface  8  opposite the exterior surface  5 , half way between the two flats  7 . The two arms  10  extend between the ring  2  and the second body  3 . The arms  10  divide the ring  2  into two portions, one of which is thicker than the other ( FIG. 1 ). The interior surface  8  has two separate levels whereas the exterior surface  5  is flat. 
   There are two facing lugs  20  on the surface  8 , at the level of the center of the flats  7 . Each of the lugs  20  is rooted on the interior surface  8  at the border with a flat  7 . The two lugs  20  are the same shape and the same size. 
   Each lug  20  has a constant profile and is attached to the interior surface  8  by a root  21  ( FIG. 1 ). The root  21  is thin, the lug  20  widening after the root  21 . 
   The section of the lug  20  has four sides. 
   The surface from which the root  21  projects is flat and faces the interior surface  8  of the ring  2 . The root  21  is in the vicinity of the edge shared with a second surface. 
   The second surface lies on the exterior, opposite the recess. It is oblique and converges towards the axis of the attachment  1  from the above edge. 
   A toe  22  extends over this second surface. The toe  22  extends over a length less than the lug  20 . Its section is generally triangular, the projecting edge  23  being rounded. Seen in elevation ( FIG. 1 ), the projecting edge  23  is offset outward relative to the remainder of the lug  20 . 
   The flat third surface is opposite the root  21  and aligned with one of the surfaces of the toe  22 . 
   Finally, the fourth surface is oblique and generally parallel to the second surface. The fourth surface includes two adjacent triangular wedge members  24  in the vicinity of the edge shared with the third surface. 
   The portion of the lug  20  that includes the toe  22  and the wedge members  24  is rigid. 
   The lugs  20  are offset axially because the ring  2  is thicker under one lug  20  than under the other. 
   The second body  3  includes a thick disk  30 . The corner between its exterior surface  31  and its lateral surface is rounded whereas the corner between its interior surface  32  and its lateral surface is right-angled. 
   The exterior surface  31  features an oblong opening opening into a shallow imprint  33  for inserting a tool for screwing in the attachment  1 . 
   The second body  3  further includes two flanges  34 . Each flange  34  is connected to the second body  3  and to a portion of an arm  10  adjoining the second body  3 . The two flanges  34  are symmetrical with respect to the axis of the attachment  1 . 
   Each flange  34  is arcuate in shape and extends almost as far as the opposite arm  10 . 
   At the junction with the arm  10 , the flange  34  extends over approximately half the height of the arm  10 . The height of the flange  34  decreases over a distance away from this junction and then remains constant. 
   The edge of the flange  34  facing the opposite arm  10  is pointed. 
   On its outside, facing a lug  20 , the flange  34  has an increased thickness portion  35  that extends its whole height. On the side opposite the second body  3 , the increased thickness portion  35  has a beveled edge over which extends a longitudinal enlargement  36  parallel to the edge. At the same level, the arm  10  corresponding also includes the same enlargement  36 . 
   Between the beveled edge of the increased thickness portion  35  and the flat  7 , which face each other, is a flexible strip  40  having two parallel edge surfaces. The strip  40  is flexible because it is relatively thin. The width of the strip  40  is equal to that of the toe  22 . It is on the outside, opposite the recess of the attachment  1 . 
   The disk  30  is offset with respect to the arms  10 , the flanges  34  and the strips  40 . 
   In the present example a skirt  51  is nested over the attachment  1  to form an obturator  50 . The skirt  51  is of molded plastics material and includes a flange  52  with a rounded profile extending from a nesting cylinder  53 . The skirt  51  is more flexible than the attachment  1 . 
   The height of the cylinder  53  corresponds to the distance between the interior surface  32  of the disk  30  and the enlargement  36 . In the present example the height of the skirt  51  is less than the height of the attachment  1 . 
   When the skirt  51  is nested over the attachment  1 , the cylinder  53  abuts against the rim of the disk  30  and the enlargement  36  assumes a position just under the junction of the flange  52  with the cylinder  53 . 
   When the attachment  1  is threaded over a stud  60  ( FIG. 8  or  9 ), the force on the first body  2  is transmitted by the rigid arms. The wedge members  24  of a first lug  20  come into contact with the stud  60 . By pivoting, the lug  20  moves away so that the wedge members  24  can climb a flank of the thread of the stud  60 . The second lug  20  rapidly reaches the stud  60  and also moves away. 
   With the insertion of the stud  60 , the lugs  20  are farther apart than in the rest state and the toes  22  come into contact with the flexible strips  40 . 
   When the wedge members  24  reach and pass the apex of the thread, because of the effect of the nesting force and the tension of the flexible strips, the attachment  1  moves a little further onto the stud  60 . The flexible strips push the lugs  20  towards the bottom of the thread, which makes a sharp sound. When the attachment  1  is fitted, the above events occur in quick succession and a succession of clicks is heard. 
   Because of the flexibility of the lugs  20  at the level of their root  21 , the attachment  1  is suitable for a plurality of diameters of the stud  60 , as shown in  FIGS. 8 and 9 . 
   The lugs each include two wedge members and the stud is gripped on each side between two wedge members  24 . Unscrewing is possible directly on the lugs, despite their flexibility. 
   With the attachment  1  threaded over a stud  60 , the flexible strips  40  are tensioned and hold the lugs  20  against the stud  60 . If removal of the member  1  is attempted and tension is exerted along the axis of the attachment  1 , the lugs  2  are braced and the strips  40  are tensioned further. Thus the lugs are retained even more firmly on the stud  60 . 
   If greater traction is applied from one side, the first body  2  pivots slightly relative to the arms  10  and the flexible strip  40  on this side stretches further. The pressure of the strip  40  on the corresponding lug  20  is greater, whereas the other lug  20  is still retained by the cooperation of the wedge member  24  and the thread and by the strip  40 , which remains tight. 
   To separate the attachment  1  from the stud  60 , it is sufficient for the user to unscrew the attachment  1 , for example using a tool inserted in the imprint  33 . 
   When the stud  60  is used facing a hole in a panel, the attachment  1  is capped by the skirt  51  to form the obturator  50  that is then fixed to the stud  60  and conceals the hole in the panel. 
   Alternatively, the component  1  is used with no skirt or in cooperation with another part. 
   In variants that are not shown, the shape and the dimensions of the various parts constituting the attachment  1  are different, for example, there are provided three lugs and only one rigid arm, and/or the lug portion including the teeth and the toe is connected to the remainder of the first body by a flexible and elongate portion. 
   The present invention is not limited to the embodiment described and shown and encompasses any variant execution thereof.