DE102020123049A1 - PART FOR A FASTENING SYSTEM AND FASTENING SYSTEM WITH THIS PART - Google Patents

Abstract

Part (1) intended to cooperate with a pin (4) to form a fastening system between two elements (2-3), comprising: - a body (6) having a flat underside (9) and a Having a cavity (7) for receiving the pin (4); - a holding member which comprises a plurality of holding tabs (8) which extend from the body (6) towards the interior of the cavity (7), having a flexible main part (19) ) which forms a spring which exerts a restoring force towards a central axis (X) on the distal part (20) of the tab when this is spaced from the axis; characterized in that the distal part (20) of each retaining tab (8) forms a cutting edge which is designed to penetrate a less hard material than the material of the retaining tab (8), and that a radially inner edge (21) of the cutting edge follows a helical section which winds around the central axis (X) with a given inclination with respect to a plane running parallel to the underside (9).

Description

Field of the Invention

The present invention relates to the implementation of a removable fastening system for assembling elements with one another, in particular at least partially panel-shaped elements, in particular vehicle body elements, and in particular a detachable part which cooperates with a pin to form such a system.

Technical background

The known fastening devices for fastening an element to a door panel, such as, for example, the upset riveting of a shaft or the attachment of a star washer (in English starlock) to a pin protruding from the panel, are easy to implement and inexpensive. In particular if the door panel is made of plastic, it is easy to place the fastening pins at the desired locations when the door panel is manufactured. During assembly, it is sufficient to push a suitable fastening tab of the element to be fastened around the fastening pin and then to carry out the upset riveting process or to attach a star washer.

Unfortunately, in this case, the element cannot simply be dismantled from the door panel without destroying or losing the device, which results in the entire panel being scrapped.

Incidentally, the control of the quality of the upset riveting is difficult and has an impact on the strength in the event of a side impact, etc. In the event of a repair, the upset rivet connection is replaced by a screw, which entails high costs.

The object of the present invention is to provide a device for the simple and reliable attachment of elements to pegs that protrude from a panel, for example a door panel of a vehicle, for example a motor vehicle, which allows simple and inexpensive dismantling and reassembly. The attachment should guarantee the connection of the element to the panel and guarantee the function under all stresses on the panel, for example when opening and closing the door or with the vibrations when driving the vehicle. It should be possible to dismantle the fastening device without destroying the pin and thus enable reassembly.

Summary of the invention

• - einen Körper, der eine ebene Unterseite und einen durch diese Unterseite hindurch mündenden Hohlraum aufweist, wobei der Hohlraum einen zylindrischen Durchgang um eine senkrecht zu der Seite verlaufende zentrale Achse lässt, so dass der Zapfen aufgenommen wird;
• - ein Halteorgan, das mehrere ähnliche Haltelaschen umfasst, mindestens zwei, die sich von dem Körper aus zum Inneren des Hohlraums hin erstrecken und rundum regelmäßig um die zentrale Achse verteilt sind, wobei die Haltelaschen einen flexiblen Hauptteil aufweisen, von dem ein radial äußeres Ende in Bezug auf den Körper feststeht und ein radial inneres Ende einen distalen Teil trägt, der dazu bestimmt ist, sich an den Zapfen anzulegen, wobei der Hauptteil radial in die zur Unterseite entgegengesetzte axiale Richtung geneigt ist und eine Feder bildet, die eine Rückstellkraft zur zentralen Achse hin auf den distalen Teil ausübt, wenn dieser von der Achse beabstandet ist.

The invention thus relates to a part intended to cooperate with a pin protruding from a substantially flat surface of a first element to form a system for fixing a second element, comprising:

• a body having a flat underside and a cavity opening through this underside, the cavity leaving a cylindrical passage around a central axis perpendicular to the side, so that the pin is received;
• - A holding member comprising a plurality of similar holding tabs, at least two which extend from the body to the interior of the cavity and are regularly distributed all around the central axis, the holding tabs having a flexible main part, of which a radially outer end in Relative to the body is fixed and a radially inner end carries a distal part which is intended to bear against the pin, the main part being inclined radially in the axial direction opposite to the underside and forming a spring which has a restoring force towards the central axis towards the distal part when it is spaced from the axis.

The part is characterized in that the distal part of each retaining tab forms a cutting edge which is designed to penetrate a less hard material than the material of the retaining tab, and that a radially inner edge of the cutting edge follows a helical section which extends with a given one Inclination with respect to a plane running parallel to the underside winds around the central axis, the characteristics of the helical line being the same for all retaining lugs.

The features of the main part of the retaining tabs of the retaining member make it possible, as in the case of a star washer, to slide a pin of suitable diameter from the underside of the body along the axis into the cavity, then to block sliding of the pin in the opposite direction by the The distal part is pressed more strongly against the pin, the more a force is exerted on the pin in this opposite direction. The second element can thus be attached to the first by placing a flat part of it around the pin and then pressing it against the surface of the first element by pressing on the part previously pushed around the pin.

Incidentally, the presence of the cutting edges at the end of the retaining tabs and their shape generate a groove that forms a thread when the part is rotated around the pin, since the material of the pin is softer than that of the retaining tabs. This thread allows the part to be removed by unscrewing it around the spigot. Once removed, the part leaves a thread on the tenon that does not prevent it from being reused with the same part, for example to attach a second element that had to be replaced. This is because the part can be pushed onto the pin again regardless of the position of the cutting edges in relation to the thread grooves. For example, a door panel with fastening pins that are integral with the panel can be used as the first element without having to scrap it when a second element attached to it is replaced.

In addition, the formation of a thread enables the part to be screwed onto the tenon after it has been pressed against the wall of the second element. This makes it possible to increase the pressure exerted by the connection system between the two elements. This has advantages in terms of the stability of the connection, the shock resistance and the reduction of spurious vibrations.

The winding angle of the helix around the axis is advantageously small, preferably between 5 degrees and 8 degrees with respect to the plane of the underside of the body. This corresponds to a thread that makes it possible to control the degree of unscrewing and to hold the part on the pin. The helical line advantageously rotates clockwise when the part is viewed from the underside, which corresponds to the usual screwing-on direction. At least two opposing retaining tabs are required to clamp the pin and ensure engagement. Advantageously, three or more regularly distributed retaining tabs allow a natural centering of the pin between the retaining tabs.

The cutting edge of the distal part is preferably formed by a thin metal sheet which is inclined radially towards the underside of the body, preferably at an angle of at least 5 degrees with a plane running parallel to the underside of the body.

The inclination of the cutting edge favors the holding of the pin by the radially inner edge against an extraction force along the axis.

More preferably, a thin sheet metal forms the main part of each retaining tab and is bent over at its free end by about 90 degrees in order to form the distal part. Advantageously, the radially inner edge of the cutting edge, which is intended to be in contact with the pin, is cut by a transverse surface formed in the thickness of the cutting edge which is inclined towards the underside of the body, preferably at an angle less than or equal to 45 degrees with a plane parallel to the bottom of the body.

The inclination of the transverse surface on the radially inner edge of the cutting edge enables the material of the pin to be notched in order to form the thread. In addition, the presence of a contact surface on the edge of the cutting edge makes it possible to draw an open groove which forms a thread with good holding surfaces in the axial direction. The smaller the difference in hardness between the material of the retaining tabs and that of the pin, the more preferable it is to increase the inclination in relation to the plane of the underside.

Advantageously, the inner walls of the body in the cavity form a stop at each retaining tab which limits the spacing of the distal part in the radial direction.

When the retaining tab is in the stop position on the wall, the cutting edge of the distal part is preferably not inclined in the direction opposite to the underside. This prevents unintentional tilting when inserting the part around the pin, which could impair the holding function or even destroy the part.

The retaining tabs are preferably metallic.

The metal ensures both greater hardness than most plastics that can be used for panels in a vehicle and good elasticity for the main part of the retaining tab.

Even more preferably, the retaining tabs are integral with a metal core that surrounds the cavity and is inserted into the body.

This gives the holding member a rigid core which ensures good stability of the part around the pin when the connection is formed.

The body is advantageously formed from a plastic.

This has at least two advantages. On the one hand, plastic dampens vibrations better than metal, for example; the attachment is therefore not a source of spurious vibrations. On the other hand, the production of a plastic part is inexpensive and can be done by injection molding.

If the retaining member has a core which forms a ring which carries the retaining tabs, the surfaces of the ring advantageously act with the Geometry of the body together to form means of positioning when rotating with respect to one another. This simplifies production by overmolding the body around the holding member and can also make it possible to exert a higher force when screwing the part around the pin.

The cavity advantageously traverses the body. This makes it possible to make a flat and compact part that can adapt to tenons of different heights.

Advantageously, the body has positioning stops of the pin, which are arranged in the cavity in such a way that the pin is arranged on the axis, the stops extending axially around the position of the distal parts of the retaining tabs.

Preferably, the body carries an annular row of compensating tabs on the circumference, which are inclined towards the underside so that their free ends are arranged at the level of the plane of the underside or below with respect to the body.

In fact, the free end of the compensation tabs is very slightly below the bottom. When the lower side is pressed against the surface of the second element, the free ends of the compensating tabs can shift due to the elasticity of the material in order to be arranged in the same plane as the lower side on the surface of the second element. This creates a repulsive force along the axis of the pin, which tensions the retaining tabs against the pin, which improves the quality of the connection between the two elements on the fastening system.

Advantageously, the body has at least two outer surfaces that are designed to provide an engagement that enables torque to be applied about the central axis.

Thus, a suitable tool can be used to easily screw the part onto or unscrew it from the spigot.

The invention also relates to a system for releasably connecting a first mechanical element to a second mechanical element, which are preferably vehicle body elements, comprising a part as described above, a cylindrical pin protruding from the first mechanical element, which has a circular cross-section with a suitable radius to pass between the retaining tabs and thereby spacing them from the central axis, and which is made of a less hard material than that of the retaining tabs, preferably from a plastic, and a panel of the second mechanical element with an opening which is designed for this to be penetrated by the pin, and at the same time forms an obstacle to the passage of the underside of the part when this is pushed around the pin. The panel of the second element can have a through hole which is designed to be penetrated by the tenon, or a groove which enables the panel to be pushed along the first element in order to arrange it around the tenon.

The pin is preferably integral with the first element.

Figure list

• [1] 1 eine perspektivische Ansicht eines erfindungsgemäßen Teils;
• [2] 2 eine Draufsicht, von der zur Unterseite entgegengesetzten Seite aus, des Teils aus 1;
• [3] 3 eine Ansicht von unten, von der Unterseite aus, des Teils aus 1;
• [4] 4 schematisch einen Axialschnitt einer Haltelasche des Teils aus 1;
• [5] 5 schematisch eine Seitenansicht eines Abschnitts des Halteorgans des Teils aus 1, die den Winkel zeigt, den das freie Ende einer Haltelasche mit einer Ebene senkrecht zur zentralen Achse bildet;
• [6] 6 eine perspektivische Ansicht, die schematisch das erste mechanische Element mit einem Zapfen und eine gegenüber angeordnete Lochung eines zweiten Elements im Hinblick auf sein Schieben um den Zapfen zeigt, wobei das Teil maßstabsgetreu über den beiden Elementen dargestellt ist;
• [7] 7 eine perspektivische Ansicht, die schematisch das zweite Element, das um den Zapfen gegen das erste Element positioniert ist, und das mit einem Handhabungswerkzeug dem Zapfen gegenüber angeordnete Teil darstellt;
• [8] 8 einen schematischen Axialschnitt der beiden Elemente und des Teils in der Position gemäß 7;
• [9] 9 eine perspektivische Ansicht, die schematisch das um den Zapfen aufgeschobene und mit einem Handhabungswerkzeug gegen die Fläche des zweiten Elements gepresste Teil nach dem in 7 dargestellten Schritt darstellt; [10] 10 einen schematischen Axialschnitt der beiden Elemente und des Teils in der Position gemäß 9;
• [11] 11 eine perspektivische Ansicht, die schematisch das um den Zapfen aufgeschobene und gerade vom Zapfen abgeschraubte Teil bei einer Demontage nach dem in 9 dargestellten Schritt darstellt;
• [12] 12 einen schematischen Axialschnitt der beiden Elemente und des vom zweiten Element beabstandeten Teils während des in 11 dargestellten Schritts;
• [13] 13 eine perspektivische Ansicht, die schematisch das vom Zapfen gelöste Teil und den aus dem zweiten Element herausragenden Zapfen nach dem Demontagevorgang darstellt;
• [14] 14 einen schematischen Axialschnitt der beiden Elemente und des Teils in der Position gemäß 13.

Further features and advantages of the invention are clarified by the following detailed description with reference to the accompanying drawings. Show it:

• [ 1 ] 1 a perspective view of a part according to the invention;
• [ 2 ] 2 a top view, from the side opposite to the underside, of the part 1 ;
• [ 3 ] 3 a view from below, from the bottom, of the part 1 ;
• [ 4th ] 4th schematically shows an axial section of a retaining tab of the part 1 ;
• [ 5 ] 5 schematically a side view of a portion of the holding member of the part 1 which shows the angle that the free end of a retaining tab makes with a plane perpendicular to the central axis;
• [ 6th ] 6th a perspective view schematically showing the first mechanical element with a pin and an oppositely arranged perforation of a second element in view of its sliding around the pin, the part being shown to scale over the two elements;
• [ 7th ] 7th Fig. 3 is a perspective view schematically showing the second member positioned around the post against the first member and the portion disposed opposite the post with a manipulation tool;
• [ 8th ] 8th a schematic Axial section of the two elements and of the part in the position according to 7th ;
• [ 9 ] 9 a perspective view schematically showing the part pushed onto the pin and pressed against the surface of the second element with a handling tool according to the part shown in FIG 7th represents step shown; [ 10 ] 10 a schematic axial section of the two elements and of the part in the position according to FIG 9 ;
• [ 11 ] 11 a perspective view schematically showing the part pushed onto the pin and just unscrewed from the pin during dismantling according to the FIG 9 represents step shown;
• [ 12th ] 12th a schematic axial section of the two elements and of the part spaced from the second element during the in 11 step shown;
• [ 13th ] 13th a perspective view schematically showing the part detached from the pin and the pin protruding from the second member after the dismantling process;
• [ 14th ] 14th a schematic axial section of the two elements and of the part in the position according to FIG 13th .

Detailed description of the invention

In the following description a part according to the invention is described 1 used ( 6th and 7th ) to provide a releasable fastening system between a first mechanical element 2 and a second mechanical element 3 execute, for example a door panel of a vehicle and a decorative element of the panel, an emblem, an insert or other vehicle body elements that are at least partially panel-shaped, ie have at least one panel-shaped connecting portion. The door panel 2 is made of plastic and has one or more pins 4th that are integral with the rest of the panel, while the second element 3 at least one panel-shaped section with a perforation 5 has, which makes it possible to this portion around one of the pins 4th of the first element 2 to put.

With reference to 1 to 3 has a part 1 according to a preferred embodiment of the invention a body 6th made of plastic, with a continuous cavity 7th is pierced, and a metallic retaining element, the retaining tabs 8th has, which are located inside this cavity 7th extend. The arrangement is around a central axis X rotationally symmetrical.

The body 6th made of plastic has an underside 9 inscribed in a plane perpendicular to the axis and the extent of the body of the part 1 in the direction of the central axis X limited.

In the figures, the central axis is from the bottom 9 out to the opposite side of the body 6th aligned. The adjectives above and below can also be used in the remainder of the text to denote what is in the direction of the axis X aligned, or what is in the opposite direction.

The outer shapes of the from the bottom 9 starting body 6th give it the basic shape of an on the axis X centered hex nut. In this example, the body points 6th six perpendicular to the bottom 9 running surfaces 10 on that around the central axis X are distributed. These six areas 10 can with a key-shaped tool 11 work together to get the part 1 around the central axis X to turn ( 7th , 9 and 11 ).

Two essentially triangular compensating tabs 12th go from each of these surfaces 10 about halfway up the body 6th along the axis X outwards. These retaining tabs 12th , here with a triangular basic shape, are inclined so that the bottom of their point, their free end 13th forms, at the level of the level of the underside 9 of the body 6th is, preferably slightly below this level. The compensation tabs 12th are integral with the rest of the body 6th . Their plastic gives them some flexibility as to the position of their tip 13th to shift slightly when the bottom 9 of the body 6th is placed on a surface so that on the part 1 a tension in the opposite direction along the central axis X is exercised.

The cavity 7th has a substantially cylindrical shape with a circular cross-section about the axis. With reference to 1 in the example show the walls of the body 6th in the cavity one with the bottom 9 connected first section 14th on, the cross section of which is circular, and one with that to the bottom 9 opposite side connected second section 15th , of which there are six radial protrusions 16 which are regularly distributed around the circumference. The radially inner end of these protrusions 16 is at a distance R1 from the central axis X that is the same for everyone. These protrusions 16 thus form centering stops for a pin 4th that is in the cavity 7th is introduced and has essentially the same radius R1 Has.

Incidentally, there are three grooves 17th with a semicircular cross-section along the axial direction in the walls of the two wall sections 14th and 15th Formed over the entire extent of the cavity. These grooves 17th are related to the presence of the holding member, and their function is explained in the description thereof.

The holding member, which is formed from a metallic material in a preferred embodiment, has a parallel to the plane of the bottom 9 of the body 6th trending ring 18th on the three retaining tabs here 8th carries, which is in the cavity 7th to the central axis X extend towards.

The ring 18th , part of which is in 3 can be seen is in the plastic body of the part around the cavity 7th at the junction between the first section 14th and the second section 15th the walls of the body 6th in the cavity 7th used. The ring 18th surrounds the cavity 7th and leaves an annular passage around the central axis X with a radius larger than the radius R1 of the space between attacks 16 is. In addition, its geometry can be designed to match that of the body 6th cooperates to get him around the central axis X secure against twisting in relation to the body.

The ring 18th has grooves with a semicircular cross-section that match those 17 of the walls of the body 6th made of plastic in the cavity 7th are matched. The presence of these grooves makes the part easier to manufacture 1 . Because the manufacture of the body 6th is preferably done by injection molding the plastic around the ring 18th of the holding element, which was previously made of metal. The three circular grooves 17th serve to hold the holding member during injection molding of the plastic body 6th to be arranged on the central spindle of the molding tool.

The ring 18th holding the retaining tabs 8th holds, forms a rigid core for the holding member, but also for the entire part 1 . It prevents deformation and enables stronger forces than the plastic body alone in the direction of the axis X to record.

The holding member has three with the ring 18th one-piece metallic retaining tabs 8th on that regularly around the central axis X are distributed and located within the cavity 7th within the axial extent of the second section 15th the walls of the body 6th and projections forming circumferentially between the stops 16 extend.

With reference to 4th and 5 become the retaining tabs 8th formed here by thin sheets of metal from the radially inner edging of the ring 18th go off. A main part 19th the retaining tab extends into the underside 9 of the body in the opposite direction, forming an angle α of slightly more than 90 °, preferably 95 degrees, with the surface of the ring, which is parallel to the underside 9 extending plane P lies. In other words, the main part 19th goes upwards, being radial to the central axis X is inclined, protruding from the walls of the body 6th that are parallel to the axis X extend at a relatively small angle, α - 90 degrees, spaced. At the end of this main part 19th is the thin sheet at essentially 90 degrees to the axis X bent over so that a distal part 20th that to the bottom 9 of the body is aligned and at an angle of essentially α - 90 degrees with one parallel to the bottom 9 extending plane P forms.

With reference to 5 it can be seen that the bending of the thin sheet between the main part 19th and the distal part 20th slightly by an angle β of preferably between 5 and 8 degrees with respect to a plane P parallel to the underside 9 is inclined, namely with all retaining tabs 8th according to the same direction of rotation around the central axis X . This causes the distal part 20th even by the same angle β in the direction perpendicular to the radial direction in the center of the retaining tab 8th is inclined.

The free end of the distal part 20th each retaining tab 8th is parallel to the central axis according to a X extending cylinder with a radius substantially equal to the distance R1 of the attacks 16 is cut. The free end thus forms a radially inner edge 21 of the distal part, which when essentially spaced R1 from the central axis X is arranged, follows a helical section which has substantially the same radius as one between the stops 16 centered pin 4th where the helix is here when looking at the part 1 from the bottom 9 winds off clockwise. The winding angle of the helix corresponds to the angle β and is between 5 and 8 degrees with respect to a parallel to the bottom 9 running level P.

With reference to 4th is the radially inner edge 21 essentially perpendicular to the flat sheet metal of the distal part 20th educated. It forms an angle of substantially equal to α with one parallel to the underside 9 trending plane to be in contact with the tenon 4th to get. The inner edge 21 is in the thickness of the thin sheet that covers the distal part 20th forms, by a transverse surface 22nd cut obliquely making an angle γ of about 130 degrees with the plane of the distal part 20th forms. This transverse surface 22nd is thus to the bottom 9 of the body 6th aligned towards and forms an angle δ of about 45 degrees with one parallel to the bottom 9 trending plane. This transverse surface 22nd makes it possible through the distal part 20th formed cutting edge, in the material of the tenon 4th penetrate and notch it to form the grooves when the part 1 around the tenon 4th is rotated.

The slope of the transverse surface 22nd of the example was defined for a metal retaining element that has a pin 4th plastic grips. The smaller the difference in hardness between the retaining tabs and the pin, the greater the interest in increasing the inclination of the transverse surface, thus the To reduce the angle δ that it forms with the plane of the underside.

With reference to 1 you can see that the distal part 20th each retaining tab 8th between the axial ends of the second section 15th the walls of the body 6th in the cavity, between two radial stops 16 , is arranged. The flexibility of the main part 19th the retaining tabs 8th allows the edges 21 the distal parts 20th to space out to the tenon 4th to let through. The minor value, α - 90 degrees, of the angle that the major part 19th forms with the axial direction, but results in a small spring deflection for the displacement of the distal parts 20th that quickly hit the walls of the body 6th in the cavity 7th if they are off the central axis X be spaced.

The use of the part 1 according to the embodiment described for fastening a second element 3 on a first element 2 such as a door panel is done, for example, in the manner described below.

With reference to 7th and 8th becomes a panel-like part of the second element 3 with a suitable perforation 5 , for example a fastening tab, opposite the pin 4th of the first element 2 to which it is to be attached and then against the wall of the first element 2 pushed, with the perforation 5 from the spigot 4th is penetrated. The first element 2 this example is here made of plastic, and the fastening pins integral with it, which it carries, are also made of plastic. The pin shown in the figures 4th is hollow, but could also be massive. The fastening part 1 turns into a tool 7th used, the one with the six axial outer surfaces 10 of the body 6th cooperates to get it around its central axis X to hold, and then opposite that from the second element 3 protruding cones 4th arranged. 8th shows in section that the radially inner edges 21 the distal parts 20th the retaining tabs 8th into one through the outer walls of the pin 4th defined cylinder occur when the central axis X of the part 1 with the axis of the journal 4th is brought into agreement.

With reference to 9 becomes the part 1 then against the wall of the second element 3 pressed, with the protruding part of the tenon 4th into the cavity 7th is inserted. The tool 7th can be used to apply a compressive force along the central axis X in the direction of the arrow A. in 9 apply to clamp the connection between the first 2 and the second 3 element.

It should be noted that during this process the projections forming the stops 16 of the body in contact with the peg 4th before it comes into contact with the free edges 21 the retaining tabs 8th so that the part 1 properly on the spigot 4th is centered. It is also noted that the wall of the body 6th in the second section 15th of the cavity 7th the radial outward displacement of the distal part 20th each retaining tab 8th limited to tilting the tab 8th outward when applying tensile force to the part 1 to prevent.

With reference to 10 at the end of this step has become the main part 19th the retaining tabs 8th bent to the tenon 4th let through, and squeezes the edges 21 against the outer wall of the pin 4th . Incidentally, the shape of the retaining tabs 8th and their connection with the ring 18th that movement that tends to the part 1 from the wall of the second element 3 to space out the inner edges 21 the distal parts 20th pushes back inward and that of the radially inner edges 21 Holding force exerted increased. The part 1 is thus in the direction of spacing from the two elements, 2 and 3, which are around the spigot 4th holds around, axially locked.

In addition, the in 9 compensating brackets shown 12th of the body 6th a tension in the direction of spacing. In this way, the device prevents the connection between the two elements from loosening due to vibrations which affect the radially inner edges during operation of the vehicle 21 the distal parts 20th due to small axial movements of the part 1 along the tenon 4th would slip off.

With reference to 9 it is also possible to increase the clamping of the connection after the axial pressing by removing the part 1 on the tenon 4th is screwed. If that part 1 using the tool 7th along the arrow B. is rotated, form the distal parts 20th Cutting whose edges 21 into the material of the tenon 4th penetrate and into it thanks to the helical shape of the edges 21 create a thread start that will allow the part to rotate 1 in an axial movement towards the underside of the pin 4th towards the second element 3 , will convert.

With reference to 11 the tool is used during dismantling 7th to the part 1 and rotates it around the axis X in the opposite direction as when mounting along arrow C. The radially inner edges 21 the distal parts 20th the retaining tabs 8th are against the wall of the tenon 4th tense and embedded in it. For the same reasons as before, they create a thread 23 on the tenon 4th . In this case the thread will 23 into the underside of the tenon 4th opposite direction and the rotation causes the part to be spaced apart 1 from the second element 3 , as in 12th is specified. At the end of the process, there is the part 1 , as in 13th and 14th indicated, completely from the spigot 4th separated, and a thread 23 is on the spigot 4th has been generated to its free end. Then the second element 3 from the spigot 4th of the first element 2 be removed.

If you then want to attach another second element to the first element, you can use the same part 1 on the same tenon 4th to take. As in 13th can be seen, the peg has 4th of the first element 3 now a thread 23 but that doesn't prevent you from using it again. Because in this case the part will 1 opposite the tenon 4th arranged and against the element 3 pressed to the connection regardless of the position of the thread 23 to tension.

The example of use shown for the invention is not restrictive. It is also possible to use them to attach second elements to a first element, the pins of which are made of metal, for example on a bonnet. Then a part must be taken in which the metal that forms the retaining element is harder than that of the pin.

The invention also relates to an embodiment variant with a part made of a single material, which is made of a material that has a sufficiently high hardness in relation to the pin to ensure the locking of the retaining tabs and dismantling by unscrewing.

Claims (10)

Part (1) intended to cooperate with a pin (4) protruding from a substantially flat surface of a first element (2) to form a system for fixing a second element (3), comprising: - a body (6) which has a flat underside (9) and a cavity (7) opening through this underside (9), the cavity (7) having a cylindrical passage around a central axis (9) perpendicular to the side (9). X) leaves, so that the pin (4) is received; - A holding member which comprises several similar holding tabs (8), at least two, which extend from the body (6) to the interior of the cavity (7) and are regularly distributed all around the central axis (X), the holding tabs ( 8) have a flexible main part (19) of which a radially outer end is fixed with respect to the body (6) and a radially inner end carries a distal part (20) which is intended to be attached to the pin (4) to apply, wherein the main part (19) is inclined radially in the opposite axial direction to the underside (9) and forms a spring which exerts a restoring force towards the central axis (X) on the distal part (20) when this from the axis is spaced; characterized in that the distal part (20) of each retaining tab (8) forms a cutting edge which is designed to penetrate a less hard material than the material of the retaining tab (8), and that a radially inner edge (21) of the cutting edge follows a helical section which winds around the central axis (X) with a given inclination with respect to a plane (P) running parallel to the underside (9), the characteristics of the helical line being the same for all retaining tabs (8). Part (1) according to Claim 1 , in which the cutting edge of the distal part (20) is formed by a thin sheet which is inclined radially to the underside (9) of the body (6), preferably at an angle of at least 5 degrees with a plane running parallel to the underside of the body (P). Part (1) according to one of the preceding claims, in which the radially inner edge (21) of the cutting edge, which is intended to be in contact with the pin (4), is supported by a transverse surface (22) formed in the thickness of the cutting edge. is cut, and which is inclined towards the underside (9) of the body (6), wherein it preferably forms an angle less than or equal to 45 degrees with a plane (P) running parallel to the underside of the body. Part (1) according to one of the preceding claims, in which the retaining tabs (8) are metallic. Part (1) according to the preceding claim, in which the retaining tabs (8) are integral with a metal core (18) which surrounds the cavity (7) and is inserted into the body (6). Part (1) according to one of the preceding claims, in which the body (6) is formed from a plastic. Part (1) according to one of the preceding claims, in which the cavity (7) penetrates the body (6). Part (1) according to one of the preceding claims, in which the body (6) carries on the circumference an annular row of compensating tabs (12) which are inclined towards the underside (9) so that their free ends (13) are level with the plane the underside (9) or below with respect to the body (6) are arranged. Part (1) according to one of the preceding claims, in which the body (6) has at least two outer surfaces (10) which are designed to provide an engagement which enables a torque to be applied about the central axis (X). A system for releasably connecting a first mechanical element (2) to a second mechanical element (3), which are preferably vehicle body elements, comprising a part (1) according to one of the preceding claims, a cylindrical pin (2) protruding from the first mechanical element (2). 4), which has a circular cross-section with a suitable radius to pass between the retaining tabs (8) and thereby spacing them from the central axis (X), and which is made of a less hard material than that of the retaining tabs (8) , preferably made of a plastic, and a panel of the second mechanical element (3) with an opening (5) which is designed to be penetrated by the pin (4) and at the same time an obstacle for the passage of the underside (9) of the part (1) forms when this is pushed around the pin.

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