The invention relates to a system for fastening a component on a carrier component, comprising a first fastening element with a fastening reception, which defines an axial direction, and a second fastening element with a fastening section, wherein the second fastening element is designed to be inserted with its fastening section in the axial direction into the fastening reception and to lock releasably on at least one locking element provided in the fastening reception in a mounting position.

Trim parts are fastened to automobile body parts, for example, using these types of systems. To this end, the first fastening element is connected to the carrier component, for example to a body part of an automobile. The component to be fastened on the carrier component, for example a trim part, is then placed onto a suitable contact surface of the first fastening element in such a manner that a through-opening of the component is in alignment with the fastening reception of the first fastening element. The second fastening element with its fastening section is then inserted through the through-opening of the component into the fastening reception such that the component is held between the contact surface of the first fastening element and a suitable oppositely-located contact surface of the second fastening element. Fastening components without such types of through-openings to carrier components, in particular by means of so-called retainers, is also known using such types of systems.

Such types of plug-in connections are advantageous, in principle, to reduce mounting expenditure. Systems, for example, where the first fastening element comprises two elastic locking tongues and the fastening section of the second fastening element has a fastening projection are known from practice. The fastening projection is pressed into the locking tongues, said locking tongues being deformed elastically outward and in the axial direction and then locking behind the fastening projection. As a result of rotating the second fastening element, the locking tongues can be pressed apart again such that the fastening projection is able to be released for removal from its lock. Detachability of this type is frequently desirable. A disadvantage in the case of the known system is that to achieve high holding forces in operation the design of the system has to be such that also requires high mounting forces. If lower mounting forces are to be achieved, correspondingly only relatively low holding forces are able to be realized. It is also necessary as a result of the cross section of the fastening projection of the second fastening element to align the second fastening element for mounting in a suitable manner in the direction of rotation. Over and above this, the known system requires a large installation space.

Proceeding from the explained prior art, the object underlying the invention is to provide a system of the type mentioned in the introduction which makes mounting and removal possible with low forces for mounting or removal and with high holding forces in operation.

The invention achieves the object by the object of claim 1. Advantageous developments can be found in the dependent claims, the description and the figures.

For a system of the type named in the introduction, the invention achieves the object in that the first fastening element comprises several locking elements delimiting the fastening reception, wherein the locking elements in each case comprise a first section starting from a carrier section of the first fastening element and extending in the axial direction, wherein in each case a second section follows the first section and extends in circumferential direction around the fastening reception and/or tangentially to this circumferential direction, wherein between the second section and the carrier section of the first fastening element a free space is formed, wherein the second section of the locking elements comprises in each case in the area of its end an area extending in radial direction into the fastening reception, and wherein at least the second section is elastically moveable in the radial direction. The system according to the invention can include the carrier component and/or the component to be fastened on the carrier component. The carrier component and the component to be fastened thereon can be, in particular, components of an automobile. For example, the carrier component can be a vehicle body part and the component to be fastened thereon can be a trim part, such as an underbody trim, a sill board, foot mats, an interior trim, insulating mats, carpets, covers, etc. In a manner known per se, the first fastening element and the second fastening element can have suitable contact surfaces which are located opposite one another in the mounting position of the system and delimit between them a free space for the component to be fastened on the carrier component. The component can have a suitable through-opening for this purpose. The contact surfaces are then designed to abut against surfaces of the component which are opposite one another. The contact surface of the first fastening element can be formed, for example, by the carrier section. The carrier section of the first fastening element can be, for example, disk-shaped.

The mounting of the component on the carrier component can be effected in the manner explained above and known per se. Thus, the first fastening element can be connected to the carrier component and the component to be fastened on the carrier component can be placed onto the first fastening element in such a manner that a through-opening of the component is aligned with respect to the opening of the fastening reception. The second fastening element with its fastening section is then inserted through the through-opening of the component into the fastening reception such that the component is held securely between the contact surfaces of the first and second fastening element in the mounting position. However, it is also possible to fasten components without a through-opening, for example by means of so-called retainers which are known per se. The first fastening element and/or the second fastening element can consist integrally in each case of plastics material, produced for example using a plastics material injection molding method.

The fastening reception of the first fastening element according to the invention is delimited by several locking elements. The locking elements can delimit, for example, a fastening reception with a circular cross section. The delimiting, in this case, does not have to be continuous in the circumferential direction. The fastening reception defines an axial direction which, as a rule, corresponds to the insertion direction of the second fastening element into the fastening reception of the first fastening element. Insofar as specifications such as radially, tangentially, along the circumference, etc. are given in the present case, said specifications relate to the axial direction of the fastening reception of the first fastening element or to the insertion direction of the second fastening element into the fastening reception.

It is possible, for example, for two, three, four or more than four locking elements to be provided. They can be provided distributed in particular uniformly over the circumference of the fastening reception. The locking elements according to the invention have a first section and a second section. The first sections of the locking elements, starting from the carrier section of the first fastening element, extend in the axial direction, in opposition to the insertion direction of the second fastening element. Second sections, which extend in the circumferential direction around the fastening reception and/or tangentially to the circumference of the fastening reception, extend in each case from the first sections. In the region of their ends, the second sections have in each case a region which extends radially into the fastening reception. Said regions can be formed, for example, by projections or thickenings of the second sections. At least the second section of the locking elements is resiliently elastically moveable in the radial direction. Over and above this, it can also be elastic in other directions, for example in the axial direction. According to the invention, at least the second sections of the locking elements are deformed elastically outward at least in the radial direction when the fastening section of the second fastening element is inserted into the fastening reception. The fastening section of the second fastening element comprises a suitable locking section which, with the locking elements in the position deformed at least radially outward, is able to move past them, the locking elements, once the locking section has moved past, moving at least radially inward again and locking behind the locking section such that the second fastening element with its fastening section is held securely in the fastening reception as a result of positive locking. In a corresponding manner, when the fastening section moves out of the fastening reception for removal, the locking elements are pushed at least radially outward again initially by the locking section of the fastening section such that said fastening section is able to move past the locking elements. The locking elements are then moved at least radially inward again into their normal position.

The geometry according to the invention of the locking elements with their radial elasticity enables high holding forces in operation whilst at the same time having low forces for mounting and removal. Mounting and removal can be repeated as often as required in practice. At the same time, the first and second fastening elements can be produced, for example, in a simple manner using a plastics material injection molding method. Over and above this, a compact design of the system is achieved.

It is possible for the second sections of the locking elements to be essentially only elastically moveable in the radial direction. The first sections of the locking elements can also be elastic in the radial direction, in particular substantially only in the radial direction. However, it is also possible for the first sections not to be substantially elastic.

According to a development, the second section of the locking elements can in each case form a free end of the locking elements. In the case of said so-called open variant, the delimiting of the fastening reception, in particular of its opening, provided by the locking elements is interrupted in the circumferential direction. Said variant does result in lower holding forces in operation, but allows for particularly low mounting forces. This can be of interest, for example, in the case of components which are fastened in the interior of an automobile where, in principle, lower holding forces are necessary.

According to a further development, the locking elements can be connected to a ring delimiting an insertion opening of the fastening reception and being provided at a distance to the carrier section. In the case of said development, the ring therefore brings about a delimiting of the fastening reception, in particular of its opening, which is closed in the circumferential direction. The, for example circular, ring imparts additional stability and robustness to the fastening reception. In the case of said development, the second sections of the locking elements, in particular, are connected to the ring and consequently do not form any free ends. This does result in higher mounting and removal forces. However, higher holding forces in operation can also be realized in the case of said development. Said development can be selected, consequently, for example in the case of components which are fastened in the outside region of an automobile where, in principle, higher holding forces are necessary. In addition, a smaller installation requirement is achieved with the same holding forces.

The second section of the locking elements can be in each case L-shaped. According to a further development, the area of the second section of the locking elements which extends radially into the fastening reception, in each case can extend increasingly radially into the fastening reception, seen in the insertion direction of the fastening section into the fastening reception which extends along the axial direction. In particular, when the second fastening element is released out of the lock in the mounting position as a result of a rotation, said development results in the second fastening element being automatically pressed out of the fastening reception in the axial direction in the course of the rotation. No pulling force is necessary, therefore, for this purpose.

According to a further development, it can be provided that the second fastening element comprises a pin section as a fastening section, which extends for example starting from a basic section, with a fastening head provided on its free end and having an enlarged cross section compared to the pin section, wherein the fastening head is designed to lock in the free spaces between the carrier section of the first component and the second sections of the locking elements in the mounting position. The pin section with the fastening head can be rotationally symmetrical wherein the second fastening element is designed to be released from the mounting position purely through a pulling force in the axial direction. For mounting, the second fastening element in the case of said development can be pressed with the pin section and the fastening head in a simple manner in the axial direction into the fastening reception. In a corresponding manner, the second fastening element can be pulled out of the fastening reception in a simple manner again as a result of a pulling force in opposition to the insertion direction. Particularly simple mounting and removal is the result. Said development allows, over and above this, for particularly low mounting and removal forces of less than 50N. In this case, desired detachability through low forces of, for example, between 100N and 200N is possible, in particular in the case of components which are to be released as a result of exerting a pulling force. Said development is once again particularly suitable in the case of components which are to be fastened in the interior of an automobile.

Over and above this, said development is of interest for the fastening of components where there is no direct access available from outside. Thus, the second fastening element, in the case of said development, can be pre-mounted on the component, for example in a retainer reception of a trim part. For mounting and removal, the component together with the second fastening element mounted thereon is then pushed into the first fastening element or pulled out of the first fastening element in a simple manner and consequently is mounted on the carrier component or removed from the carrier component. A certain alignment of the second fastening element for the mounting is not necessary as a result of the rotationally symmetrical development. The rotationally symmetrical development, over and above this, can also compensate well for an axial offset of the pin section with respect to the axial direction of the fastening reception. To this end, the fastening head can be, for example, in the form of a ball or a flattened ball.

According to a further development, it can be provided that ribs are provided on the pin section which correspond in number and provision over the circumference of the fastening reception to the locking elements of the first fastening element, wherein the second fastening element is designed to be released from the mounting position through a rotation about the axis of the pin section, wherein the ribs come into contact with the areas of the second sections of the locking elements which extend radially into the fastening reception and push the second sections radially to the outside for a release from the mounting position. The ribs in the case of said development are therefore distributed over the circumference of the fastening reception in particular at identical angular distances as the locking elements. If, for example, four locking elements are provided distributed uniformly over the circumference of the fastening reception, four ribs are also provided distributed uniformly over the circumference of the pin section. The ribs provided on the pin

section of the second fastening element, in this case, can be developed such that, under tensile load, they block the second sections of the locking elements and consequently securely prevent a release of the second fastening element in the event of a tensile load and at the same time increase the holding force.

In the case of the aforementioned development, for removal the second fastening element has to be rotated about the axis of the pin section, for example by 45° or 90°. The rotation results in the second sections of the locking elements of the first fastening element being pressed radially outward by the ribs of the second fastening element pressing against the regions protruding radially into the fastening reception such that the fastening head is released from its lock in the free space between the second sections of the locking elements and the carrier section of the first fastening element. Releasing the second fastening element from the mounting position purely by a pulling force in the axial direction is only possible in this connection by applying extremely strong pulling forces and where applicable destroying the components involved. Depending on the rotational alignment, a rotation can also be carried out when inserting the fastening section into the fastening reception. This is effected automatically during mounting, however, as a result of the geometry of the second fastening element such that, once again, no previous alignment is necessary for mounting. Higher mounting and removal forces are certainly required in the case of said development and rotation of the second fastening element is necessary. For this, however, higher holding forces of, for example, in excess of 400N can be realized in operation. Said development is therefore, once again, particularly suitable in the case of components which are to be fastened in the outside region of an automobile. As mentioned above, by suitably developing the regions of the second sections of the locking sections which project radially into the fastening reception, the second fastening element can be pressed out of the fastening reception in the axial direction at the same time during the course of the rotation without any tensile force being necessary for this purpose. The ribs of the pin section of the second fastening element can extend in the axial direction between the basic section and the fastening head of the second fastening element. In addition, the ribs can have an increasing extension in the circumferential direction around the fastening reception, seen in a direction of the fastening head to the basic section. Said development of the ribs once again results in the second fastening element, when rotating about the axis of its pin, being moved out of the fastening reception in the axial direction at the same time for release from the mounting position.

According to a further development, the basic section of the second fastening element can form the bottom of a pot-shaped section, wherein the opening of the pot-shaped section facing away from the basic section is delimited by a surrounding elastic collar. The elastic collar forms a contact surface, against which the component to be fastened on the carrier component abuts by way of a side in the mounting position. In addition, several securing ribs can be provided on the inner wall of the pot-shaped section and extend in the axial direction. The securing ribs can abut against the locking elements of the first fastening element from the outside in the mounting position and thus provide for additional stability.

The first fastening element can be designed to be glued to the carrier component with a side of its carrier section facing away from the locking elements. As an alternative to this, it is possible for the first fastening element to comprise at least one locking section on a side of the carrier section facing away from the locking elements, with which locking section the first fastening element can be locked on the carrier component. The locking section can include, for example, one or several elastic locking legs which lock behind a suitable through-opening of the carrier component. The locking legs can have in each case several step-shaped locking stages, locking at different stages being effected in dependence on the thickness of the carrier component. The system can be adapted in a flexible manner to different component thicknesses in this way. The system can also include the carrier component, the first fastening element with its carrier section being connected in a positively bonded manner to the carrier component, for example using an injection molding method.

The invention provides a mountable and removable quick-fixing system in a simple manner. Whilst use in the automobile sector is preferred, use is also possible outside of the automobile sector. Low mounting forces of less than 5 ON can be realized. Very high holding forces of more than 400N can also be realized at the same time as a result of suitable development. The system has a large degree of flexibility with regard to the range of application.

Exemplary embodiments of the invention are explained in more detail below by way of figures, in which, in a schematic manner: fig. 1 shows a perspective view of a first fastening element of a system according to the invention according to a first exemplary embodiment, fig. 2 shows a perspective view of a second first fastening element of a system according to the invention according to a first exemplary embodiment, fig. 3 shows a perspective view of the first fastening element from figure 1 and the second fastening element from figure 2 in a pre-mounting position, fig. 4 shows a perspective view of the first fastening element from figure 1 and the second fastening element from figure 2 in the mounting position, fig. 5 shows a perspective sectioned view of the mounting position shown in figure 4, fig. 6 shows a further sectioned view of the mounting position shown in figure 4, fig. 7 a perspective view of a first fastening element of a system according to the invention according to a second exemplary embodiment, fig. 8 shows a further perspective view of the first fastening element from figure 7, fig. 9 shows a perspective view of a second fastening element of a system according to the invention according to a second exemplary embodiment, fig. 10 shows a perspective view of the first fastening element from figure 7 and the second fastening element from figure 9 in a mounting position, fig. 11 shows a perspective view of a first fastening element from figure 7 and the second fastening element from figure 9 in a further operating position, fig. 12 shows a perspective view of a first fastening element of a system according to the invention according to a third exemplary embodiment, fig. 13 shows a further perspective view of the first fastening element from figure 12, fig. 14 shows a view from above of the first fastening element from figure 12, fig. 15 shows a sectioned view of the first fastening element from figure 12 and fig. 16 shows a further sectioned view of the first fastening element from figure 12.

Insofar as nothing to the contrary is specified, the same references in the figures designate the same objects. The first fastening element shown in figure 1 has a, for example, circular disk- shaped carrier section 12 on which four locking elements are arranged in the example shown. The locking elements delimit between them a fastening reception 14, which defines an axial direction which, in the example shown, coincides with the surface normal extending through the center of the circular disk-shaped carrier section 12. The locking elements are distributed uniformly over the circumference of the fastening reception 14. First sections 16 of the locking elements, starting from the carrier section 12, extend in each case upward in the axial direction in figure 1. Second sections 18, which extend in each case in the circumferential direction around the fastening reception 14, follow the first sections 16, a region 20, in particular a projection, which protrudes radially into the fastening reception 14, is realized in each case on the free ends of said second sections in figure 1. The second sections 18 with their regions 20 which protrude radially into the fastening reception are resiliently elastic in the radial direction. It can also be seen in figure 1 that the second sections 18 with the regions 20 which protrude radially into the fastening reception are in each case realized in an reshaped manner. It can additionally be seen that the regions 20, which protrude radially into the fastening reception, extend in each case increasingly radially into the fastening reception 14, seen in the insertion direction of a fastening section into the fastening reception 14, in figure 1 in the axial direction from top to bottom. A free space 21 is formed in each case between the second sections 18 and the carrier section 12.

Figure 2 shows a second fastening element which has a pot-shaped section. A basic section 22 forms the bottom of the pot-shaped section. A pot-shaped wall 24, which extends in a circular ring-shaped manner and at the top end of which is provided a circumferential elastic collar 26, rises from the basic section 22. In the example shown, four security ribs 28, which are distributed uniformly over the circumference and extend in the axial direction, are arranged on the pot-shaped wall 24. A fastening section of the second fastening element extends centrally starting from the basic section 22. The fastening section comprises a pin section 30 which extends starting from the basic section 22 with a fastening head 32 which is provided on its free end and has an enlarged cross section compared to the pin section 30. In the example shown, four ribs 34 which are uniformly distributed over the circumference of the pin section 30 are realized on said pin section. The ribs extend in the axial direction of the pin section 30 between the basic section 22 and the fastening head 32. In addition, it can be seen in figure 2 that the ribs 34 have in each case an increasing extension in the circumferential direction around the pin section 30, seen in the direction of the fastening head 32 to the basic section 22. On one side of the ribs 34, the fastening head 32 has in each case a recess 36 directly adjacent the ribs 34.

As can be seen in figures 3 and 4, the second fastening element with its fastening section is inserted into the fastening reception 14 of the first fastening element in an insertion direction which corresponds to the axial direction of the fastening reception 14. It can be seen in figures 5 and 6, for example, that in the mounting position there is a free space 38 which extends in the manner of a circular ring between the surfaces of the carrier section 12 and of the elastic collar 26 facing one another. Said free space serves in a manner known per se for receiving a component comprising a through-opening. The side 40 of the carrier section 12 located opposite the locking elements and which can be seen in figure 3 serves for gluing the carrier section 12 to a carrier component. In this way, the component comprising a through- opening can be fastened on the carrier component in a manner known per se. It can be seen over and above this in figure 4 that the fastening element shown in figure 2 has a hexagonal form on its underside, by means of which it can be rotated using a suitable tool.

In the course of inserting the fastening section of the second fastening element into the fastening reception 14 of the first fastening element, the second sections 18 of the locking elements with their regions 20 protruding radially into the fastening reception are pressed radially outward by the fastening head 32 and the ribs 34 such that the fastening head 32 is able to move past the second sections 18 of the locking elements, the second sections 18 then moving radially inward again into their normal position and locking under the fastening head 32, as can be seen in figures 5 and 6. In said locked position, the second fastening element, and in particular the fastening head 32 is secured against a release out of the mounting position as a result of a pulling force along the axial direction 42 of the fastening reception shown in figure 6. To release the second fastening element out of the mounting position, said fastening element has rather to be rotated about 90° in the example shown. In this case, the second sections 18 of the locking elements are pressed radially outward by the ribs 34 of the fastening section such that the fastening head 32 is able to be released from the lock. The development of the regions 20 which protrude radially into the fastening reception, on the one hand, and of the ribs 34, on the other hand, ensures that the second fastening element is moved out of the fastening reception 14 in the axial direction at the same time in the course of the rotation without a separate pulling force being necessary for this purpose. In this way, mounting and removal is possible in a manner which can be repeated as often as required in practice. Low mounting forces are achieved with high holding forces.

Figures 7 and 8 show a first fastening element which corresponds to a great extent to the fastening element shown in figure 1. In contrast to the fastening element from figure 1 , the carrier section 12 is provided with a ring-shaped sealing lip 44 on its circumference. Over and above this, the carrier section 12 in the case of the exemplary embodiment in figures 7 and 8 is not provided to be glued onto a carrier component, but for locking on a suitable through- opening of the carrier component. To this end, the fastening element from figures 7 and 8 has on the side of the carrier section 12 facing away from the locking elements a locking section 44, by way of which the first fastening element can be inserted into a suitable through-opening of the carrier component. To this end, several, for example four elastic locking legs 46, 48 are provided on the locking section 44 distributed over the circumference. The locking legs 46, 48 comprise locking stages 50, 52 arranged in each case in the manner of steps in the region of their free ends. Said locking stages lock on the through-opening of the carrier component in dependence of the thickness of the carrier component. For the rest, the development and operation of the fastening element of figures 7 and 8 and in particular the development of the locking elements is identical to the development and operation of the fastening element shown in figure 1.

Fig. 9 shows a second fastening element according to a second exemplary embodiment. Said fastening element has a circular disk-shaped basic section 54, proceeding from which extends a pin section 56, on the free end of which is provided a fastening head 58 with a cross section which is enlarged compared to the pin section 56. The fastening head 58 is in the form of a flattened ball. The second fastening element shown in figure 9 is rotationally symmetrical. It can be inserted, for example, into the fastening reception 14 of the first fastening element shown in figures 7 and 8, as shown in figure 10. In contrast to the second fastening element shown in figure 2, the rotationally symmetrical second fastening element from figure 9 can be simply pressed in the axial direction into the fastening reception 14, the fastening head 58 once again locking in the free spaces 21 formed between the second sections 18 and the carrier section 12. In the same way, the second fastening element from figure 9 can be released from the fastening reception 14 in a simple manner by exerting an axial pulling force in the axial direction. As a result, particularly simple mounting and removal is produced, in particular in the case of restricted accessibility from the outside. As can be seen over and above this in figure 11, a retainer 60, which is known per se, of the component to be fastened on the carrier component can be fastened in a locking manner on the basic section 54 of the second fastening element.

Figures 12 to 16 show a further exemplary embodiment of a first fastening element according to the invention. As in the case of the exemplary embodiment shown in figure 1 , four locking elements distributed uniformly over the circumference of a fastening reception 64 extend from a, for example, circular disk- shaped carrier section 62. The locking elements have in each case first sections 66, which proceed from the carrier section 62 in the axial direction of the fastening reception 64, in figure 12 proceeding upward centrally from the carrier section 62 in the normal direction, followed by second sections 68 which extend in each case in the circumferential direction around the fastening reception 64 (see figures 13 and 15). On their ends, the second sections 68, once again, have in each case a region 70 which projects in the radial direction into the fastening reception 64. Over and above this, the locking elements and in particular their first and second sections 66, 68 are connected to a ring 72 which delimits an insertion opening of the fastening reception 64 in a circular manner and is arranged at a distance to the carrier section 62. The ring 72 is not shown in the sectioned view of figure 15.

The first fastening element shown in figures 12 to 16 can interact for example with the second fastening element shown in figure 2 or also with the second fastening element shown in figure 9. The operation is as explained for the previous exemplary embodiments. In particular, at least the second sections 68 with their regions 70 which protrude radially into the fastening reception are resiliently elastic in the radial direction such that the fastening head of the second fastening element can lock in the abovementioned manner in the free spaces 74 between the second sections 68 of the locking elements and the carrier section 62. The ring 72, as a circular delimitation of the opening, contributes additional stability and robustness to the fastening reception. Whilst the mounting and removal forces in the case of the exemplary embodiment of figures 12 to 16 are somewhat higher compared to the above- explained exemplary embodiments, even higher holding forces can be realized in the case of the exemplary embodiment of figures 12 to 16.

As in the case of the exemplary embodiment of figure 1, the carrier section 62 of the first fastening element of figures 12 to 16 can be glued by way of its underside 76 shown in figure 13 to a carrier component. It is naturally also possible in the case of the exemplary embodiment of figures 12 to 16 to provide a suitable locking section on the underside 76 of the carrier section 62, in a manner corresponding to the exemplary embodiment of figures 7 and 8, such that the first fastening element can lock on a suitable through-opening of the carrier component.

All the first and second fastening elements shown can be produced, for example, integrally using a plastics material injection molding method.