[0001] The present invention relates to a pre-assemblable and removable retaining device, for connecting, in a removable manner, in other words with the possibility of repeated assembly and dismantling without the risk of damage, two mechanical elements, in particular consisting of vehicle body elements, for example for securing an insulating pad or panel to the inside of the bonnet or the inside of a door of a vehicle.

[0002] In the motor vehicle sector, to secure vehicle body elements together, for example an internal finishing panel to the frame of a door or a side of the passenger compartment of a vehicle, or an insulating element (panel or pad) to the inside of the bonnet, the use is known of retaining devices of various types, with snap-engagement or bayonet fitting means, in general made by moulding a synthetic plastic, in one or more parts.

[0003] However, the solutions known to date often do not allow the retaining devices to be removed, for example for maintenance work, without at least the risk of damaging said devices. Moreover, retaining devices are generally assembled on a production line, one at a time, which takes a great amount of time and it is impossible to automate the assembly operation. Lastly, even in cases in which the retaining devices are successfully pre- assembled in the necessary positions on the covering element to be secured to the vehicle body, not only may the retaining devices accidentally come off during transport but, in particular, the covering element with the pre-assembled retaining device takes up a lot of room, making transport difficult and expensive.

[0004] It is an aim of the present invention to overcome the disadvantages of the prior art, providing a retaining device with a structure that is simple, reliable, compact and relatively inexpensive, for securing two elements together, in particular two vehicle body elements, quickly and such that it may be easily dismantled without the risk of damaging the elements secured using said device, and above all one which may be pre-assembled easily and securely, for example on a covering element to be secured to the vehicle body, without increasing the space taken up to an unacceptable degree. [0005] The present invention therefore relates to a retaining device and a system for removably connecting a first mechanical element to a second mechanical element, in particular vehicle body elements, as defined in the attached claims.

[0006] Further features and advantages of the present invention will become clear from the description below of one possible embodiment of the invention, provided purely by way of non-limiting example, with reference to the attached drawings, in which:

[0007] Figure 1 shows a perspective three-quarter view from below of a retaining device made according to the invention;

[0008] Figures 2 and 3 show, on a smaller scale, two orthogonal views in elevation, oriented with respect to one another by 90°, of the retaining device of Figure 1;

[0009] Figures 4 and 5 show, schematically in elevation, two different configurations that the retaining device of Figure 1 may have, and the steps for pre-assembly of the retaining device on a first mechanical element shown in section, in particular consisting of a vehicle covering element;

[0010] Figures 6, 7 and 8 show, schematically in elevation, the steps for securing, according to the system for connection according to the invention, using the retaining device of Figure 1, the first mechanical element on a second mechanical element, in particular consisting of a vehicle body sheet;

[0011] Figure 9 shows a perspective three-quarter view from above of two retaining devices of the invention secured to two different first mechanical elements, in a

configuration for transport and presented on the second mechanical element;

[0012] Figure 10 shows a perspective three-quarter view from above of two retaining devices of the invention coupled in the transport configuration but rotated by 90° with respect to Figure 9, presented on the second mechanical element, to better illustrate the connection system of the invention; [0013] Figures 11 and 12 show, schematically in elevation, the steps of dismantling the first mechanical element from the second mechanical element by means of the connection system and the retaining device of the invention;

[0014] Figures 13 and 14 show schematically a three-quarter front and rear perspective view of a different embodiment of the retaining device of the present invention; and

[0015] Figure 15 shows schematically and in an elevation view of the step of dismantling the first mechanical element from the second mechanical element by means of the connection system and the retaining device according to the embodiment of figures 13 and 14.

[0016] With reference to Figures 1 to 5, the reference sign 1 indicates, as a whole, a retaining device that may be connected to a first mechanical element 2 and to a second mechanical element 3, in particular consisting of vehicle body elements, shown only schematically and only partially, for simplicity.

[0017] Preferably, the mechanical element 2 consists of an insulating covering element in the form of a panel or pad, while the mechanical element 3 consists of a vehicle body part in the form of a sheet, for example a door or bonnet.

[0018] The retaining device 1, as will be seen below, may come pre-assembled on the mechanical element 2 so that it may then be used to secure the mechanical element 2 to the mechanical element 3, removably. To this end, the mechanical element 2 has at least one through-perforation 4 in a form suitable for receiving, passing through it, as will be seen below, a retaining device 1, and the mechanical element 3 has at least one through- perforation 5 in a form such that it may be snap-engaged, as will be seen below, by the retaining device 1.

[0019] Together, one or more retaining devices 1 and the through-perforations 4 and 5 of the mechanical elements 2 and 3 form a system 6 (Figures 6-8 and 11-12) for connecting together, removably, the mechanical elements 2 and 3 in a quick and automatable manner.

[0020] The retaining device 1 comprises a first plate body 7 delimited between a first, upper, face 8 and a second, lower, face 9, opposite to the first face 8; preferably, the faces 8 and 9 are flat. The plate body 7 is also passed through centrally, transversely to the faces 8,9, by a through-perforation 10, rectangular in the example shown.

[0021] The retaining device 1 further comprises a second plate body 11 delimited between a third, upper, face 12 and fourth, lower, face 13, opposite to the third face; the plate body 1 1 is formed as a rectangular frame so as to delimit internally a second through- perforation 14, which is rectangular, arranged transversely with respect to the faces 12,13.

[0022] The plate body 11 is arranged facing the plate body 7 and the second through- perforation 14 is facing the through-perforation 10 so that the first face 8 is directed away from the second plate body 11, the second face 9 is directed towards the second plate body

11, the third face 12 is directed towards the first plate body 7 and the fourth face 13 is directed away from the first plate body 7.

[0023] The retaining device 1 further comprises, according to a first aspect of the invention, at least one pair of opposite articulated arms 15 which connect the face 9 of the first plate body 7 to the second plate body 1 1 without interfering with the third face 12 and with respective opposite first sides 16, which are straight, of the plate body 11, said sides 16 facing the articulated arms 15.

[0024] To this end, the plate body 11 formed as a frame is provided, on the two opposite sides 16, with respective feet 17 which project out therefrom on the same side of the fourth face 13 and the arms 15 are articulated, as will be seen below, directly to the feet 17 and therefore below the sides 16, i.e. beyond the sides 16 in the direction coming from the face

12, towards the face 13.

[0025] Each articulated arm 15 is provided with opposite end hinges 18 (Figures 1 and 3), by means of which it is connected respectively to the face 9 of the plate body and to a foot 17 of the plate body 11 under each side 16, and with a central hinge 19 arranged between the end hinges 18 so that the articulated arms 15 are able to assume selectively an extended configuration (Figures 1,3,4), in which the plate bodies 7, 11 are located in a distal position, spaced apart from one another by substantially the whole length of the arms 15, and a folded-up configuration (Figures 5,8,10), in which the plate bodies 7, 11 are adjacent in a vicinal position. [0026] The retaining device 1 further comprises, according to one aspect of the invention, a pair of opposite, elastically deformable, first teeth 20 and respective engaging seats 22 (Figure 1) for the teeth 20; the teeth are provided integrally on the plate body 7 and project out from the face 9 towards the plate body 11, terminating in respective L-shaped engaging ends 21 (Figures 1 and 3) facing each other; the engaging seats 22 (Figure 1) for the teeth 20 are formed in the plate body 11 at the sides 16 and face towards the articulated arms 15, in this case they are formed on the outside of the feet 17 under the sides 16.

[0027] The teeth 20 are arranged between the articulated arms 15 and the first sides 16 of the second plate body 11 to snap-engage inside the engaging seats 22 with their engaging ends 21 when the plate bodies 7,11 are situated in the vicinal position, in which the plate bodies 7, 11 are apart by a distance substantially equal to the length by which the teeth 20 project; when the teeth 20 snap-engage inside the seats 22, moreover, the teeth 20 lock the articulated arms 15 in the folded-up configuration.

[0028] The second plate body 11 is smaller than the first plate body 7 and has a length measured between its opposite first sides 16 substantially equal to the distance between the elastically deformable opposite teeth 20; moreover, the articulated arms 15 are formed so that in the folded-up configuration they are arranged substantially parallel to the faces 8,9 of the plate body 7 and spaced from the face 9 on the side where the second plate body 11 is situated, so as to delimit between the folded-up arms 15 (Figure 5) and the face 9 a receiving space 23 for the mechanical element 2 (Figure 5).

[0029] Furthermore, in the folded-up configuration, the articulated arms 15 are arranged substantially flush with the second plate body 11 and with the central hinge 19 arranged substantially flush with the engaging ends 21 of the elastically deformable teeth 20.

[0030] The teeth 20, moreover, engage with the engaging seats 22 immediately underneath the first sides 16 of the plate body 11, such that the articulated arms 15 are attached to the feet 17 by means of respective end hinges 18 immediately below the engaging seats 22.

[0031] In the preferred embodiment shown, the articulated arms 15, the plate bodies 7,11 and the teeth 20 are made in one piece of a moulded, synthetic, plastic material; in particular, the articulated arms 15 are formed integrally with the plate bodies 7, 11 by means of a single moulding operation and the end hinges 18 and central hinge 19 are plastic hinges defined by respective thinned and elastically flexible portions 24 (Figures 1 and 3) of the articulated arms 15.

[0032] According to a further aspect of the invention, the first plate body 7 is provided integrally in one piece, between the teeth 20, with a pair of substantially rigid uprights 25 which are arranged substantially parallel to and facing each other and which extend projecting from the face 9, parallel to the teeth 20, and towards the face 12, inside a predetermined perimetral volume of the through-perforation 14; in particular, the uprights 25 are formed in a position immediately adjacent to opposite first sides 26 (Figures 9, 10) of the through-perforation 10 parallel to and facing the sides 16 of the plate body 11.

[0033] The uprights 25 each comprise a root portion 27 arranged towards the plate body 7 and an end portion 28 arranged towards the plate body 11 and are transversely connected together, at the end portions 28, by a pair of elastically deformable cross-bars 29 (Figures 1 and 9) arranged parallel and spaced relative to each other and perpendicular to the sides 16 so as to form with the uprights 25 a three-dimensional frame structure.

[0034] According to one aspect of the invention, each cross-bar 29 (Figures 1, 9 and 10) is provided in the middle with a tooth 30 which is arranged perpendicularly relative to the teeth 20 (in the sense that it lies in a plane perpendicular to that in which the teeth 20 lie) and which projects out from the cross-bar 29 towards the face 9 and between the uprights 25; each cross-bar 29 has a thinned rectangular cross section and is thus designed to form a plastic hinge which allows a relative rotation of the respective tooth 30 and the plate body 7 about an axis A (Figure 3) perpendicular to the uprights 25 and to the sides 16; the uprights 25, the respective cross-bars 29 and the respective teeth 30 are moreover configured so as to be received inside the through-perforation 14 when the articulated arms 15 are in the folded-up configuration (Figure 5).

[0035] Each tooth 30 comprises a free end 31 directed towards the face 9 and provided parallel to the cross-bars 29 with an L-shaped indentation 32 situated on the opposite side to the other tooth 30 and towards a perimetral edge 33 of the plate body 7. [0036] The L-shaped indentation 32 is delimited between a first surface 34 and a second surface 35, in the example shown flat and angled with respect to one another so as to form a slightly obtuse angle, hence slightly greater than 90°.

[0037] The surface 34 is directed towards the face 9 and is designed to snap-engage, during use, as will be seen below, underneath a perimetral edge 36 (Figure 10) of the through-perforation 5 of the second mechanical element 3, in such a way as to connect the latter to the mechanical element 2.

[0038] The surface 35 is angled with respect to the surface 34 and is directed towards the perimetral edge 33; it is also designed to cooperate, in the folded-up configuration of the articulated arms 15, with a respective second side 45 of the plate body 11 on the inside of the through-perforation 14 (Figure 9) so as to serve as an end-of-rotation stop for the respective tooth 30.

[0039] According to one essential feature of the invention, a stacking reception seat 40 for another identical retaining device 1 is provided between the first and second plate body 7, 11 at the first plate body 7 and integrally in one piece thereto.

[0040] In this manner, in the folded-up configuration of the articulated arms 15, the retaining device 1 described above is able to be stacked with one or more identical retaining devices 1, possibly each already secured, or pre-assembled, as will be seen below, to/on a mechanical element 2.

[0041] To this end, the root portion 27 of each upright 25 is internally hollow and defines on the side where the face 8 is situated a reception seat 37 (Figures 9 and 10) for the end portion 28 of an upright 25 of another identical retaining device 1; the seat 37 moreover faces, and communicates with, the through-perforation 10.

[0042] Furthermore, each tooth 30 is delimited, in a direction perpendicular to the sides 16, between a first flat surface 38 and a second flat surface 39 (Figures 7 and 9), both oblique with respect to the plate bodies 7, 11.

[0043] The flat oblique surface 38 of each tooth 30 is directed towards the inside of the through-perforation 10 and delimits, together with the perforation 10 and with the reception seat 37 of the root portion 27 of each upright 25, the stacking reception seat 40 (Figure 9), in the example shown in the shape of a cross, for another identical retaining device 1.

[0044] This seat 40 makes it possible to receive inside each device 1 all, or most, of the three-dimensional frame structure formed by the uprights 25 and by the cross-bars 29 with the teeth 30 of another device 1, thus making it possible to stack several devices 1 compactly, as long as the arms 15 are already in the folded-up configuration.

[0045] The second flat oblique surface 39 of each tooth 30, which is situated on the opposite side to the through-perforation 10 and towards the perimetral edge 33, is in fact designed to selectively mate with the first flat oblique surface 38 of a corresponding second tooth 30 of another identical retaining device 1, as clearly shown in Figures 9 and 10.

[0046] Moreover, the second flat oblique surface 39 of each tooth 30 is also designed to cooperate in use with the perimetral edge 36 of the through-perforation 5 of the mechanical element 3 to be connected to the first mechanical element 2 during insertion, as will be seen below, of the device 1 in the perforation 5, applying to the teeth 30 a flexing stress directed towards the inside of the through-perforation 10, and consequently, by means of the teeth 30, to apply to the cross-bars 29 a torsional stress able to elastically deform the cross-bars 29 to cause rotation of the teeth 30 towards the inside of the through-perforation 10.

[0047] Lastly, according to a final but no less important feature of this embodiment of the invention, each cross-bar 29 is provided, projecting on the opposite side to the respective tooth 30 and inside the through-perforation 10, with a third tooth 41 (Figures 9 and 10) arranged parallel to the sides 16 and provided towards the face 9 with an oblique surface 42 (i.e. forming an inclined plane) designed to cooperate in use with a tool 43 (Figures 11,12) which can be introduced through the through-perforation 10 so as to apply to the cross-bars 29 a torsional stress able, again, to cause rotation of the teeth 30 towards the inside of the through-perforation 10.

[0048] On the basis of the above description, it is clear that the invention also relates to the system 6 for removably connecting a mechanical element 2 to a second mechanical element 3, in particular consisting of vehicle body elements, comprising at least a retaining device 1, at least a through-perforation 4 formed through the first mechanical element 2 for each device 1 present, and at least a second through-perforation 5 formed through the second mechanical element 3 for each device 1 present and designed to be snap-engaged by the teeth 30.

[0049] According to the invention, the through-perforation 4 is smaller than the transverse dimensions of the first plate body 7 and designed to be passed through by the second plate body 11, by the uprights 25 with the cross-bars 29 and the teeth 30, and by the articulated arms 15 when the latter are in the extended configuration. The through- perforation 4 is also designed to be smaller than the transverse dimensions of the arms 15 when the latter are in the folded-up configuration, so that the arms 15 in the folded-up configuration interfere with the mechanical element 2, locking it in the reception space 23 between the plate body 7 and the folded-up arms 15; in this way, when the teeth 20 snap- engage with the respective engaging seats 22, the retaining device 1 remains preassembled, securely and permanently, on the first mechanical element 2.

[0050] Therefore, according to the invention, a plurality of retaining devices 1 are obtained by moulding with the arms 15 in the extended position and are then each inserted, still with the arms 15 in the extended position, into a through-perforation 4 of an element 2 to be assembled, until the face 9 is brought against the element 2. The arms 15 are then brought into the folded-up configuration, for example simply by pushing the plate body 11 towards the plate body 7, until they are locked by the teeth 20.

[0051] Next, a plurality of elements 2 provided with pre-assembled devices 1 may be stacked one on top of the other, taking up almost the same amount of space that they would take up if the devices 1 were not present. Indeed, as clearly shown in Figure 9, the devices 1 integral with each element 2 may be stacked one within the other thanks to the presence of the reception seats 40. Further space may be saved in the direction of stacking by giving each perforation 4 (Figure 4) a recess 44 formed on a face of the element 2 intended to face the element 3 and designed to house the arms 15 in the folded-up configuration (Figure 5).

[0052] After that, the elements 2 provided with the pre-assembled devices 1 are separated and are each coupled by snap-engagement, one at a time and in a single operation, to an element 3, simply by inserting the teeth 30, which project from the element 2 (whereas they were previously housed in the seats 40 when the elements 2 were stacked) into the perforations 5. The latter, to allow the arms 15 to also be housed in the folded-up configuration, must be buttonhole-shaped, as clearly shown in Figure 10, or have greater transverse dimensions in the direction of the axis A.

[0053] During the movement of insertion in the perforations 5, the teeth 30 come into contact with the edge 36 through the oblique surfaces 39 and the thrust of insertion causes elastic torsional deformation of the cross-bars 29, allowing the teeth 30 to get past the edge 36 so as to snap-engage it with the surfaces 34, thus locking the element 2 on the element 3 securely, by means of an operation that is simple and may thus be automated.

[0054] The teeth 30 are also designed in such a way that, after snap-engaging under the edge 36, they may be caused to rotate towards the inside of the perforation 10 of the plate body 7 by pressing on the oblique surface 42 of the teeth 41 from inside the perforation 10 using the tool 43, which may also simply be a screwdriver.

[0055] This thrust in the direction of insertion of the teeth 30 in the perforation 5 causes further elastic torsion of the cross-bars 29, which disengages the surfaces 34 of the teeth 30 from the edge 36 of the perforation 5, making it possible to remove the device 1 from said perforation 5, releasing the element 2.

[0056] It is thus clear from the above description that the retaining device 1 may be pre- assembled quickly, securely and permanently on a mechanical element to be attached, without increasing the size thereof substantially, and then said mechanical element may be secured to a second mechanical element duly equipped with perforations 5 of suitable shape simply by pushing the device 1 into the perforation 5. Thereafter, the element 2 may be attached to and dismantled from the element 3 simply by acting on the teeth 41, without any risk of damaging the device 1.

[0057] Referring now to figures 13 to 15, it is shown a second embodiment lb of the retaining device of the invention, configured to engage in a different manner a different mechanical element 3 to be connected with the mechanical element 2. The details similar or identical to those as already described are indicated with the same reference numbers for sake of simplicity.

[0058] The device lb is essentially identical to the device 1 already described, except for the engagement elements provided at the first plate body 7, which are configured to snap engage, instead with a through perforation, with a threaded stud 100 (figure 15) provided integral with the mechanical element 3, projecting in cantilever fashion therefrom.

[0059] At this end, the first plate body 7 is provided integrally in one piece, between the first teeth 20, with a pair of substantially rigid and flat uprights 250 having a wing-shape, which are arranged substantially parallel and facing to each other and which extend projecting at a first end portion 251 thereof from the second face 9 and towards the third face 12, inside a perimetral volume of the second through-perforation 14, and at a second end portion thereof 252, opposite the first end portion 251, from the first face 8 and in a position immediately adjacent to the opposite first sides 26 of the first through-perforation 10, parallel and at least partially facing to the first sides 16 of the second plate body 11.

[0060] Between the first and the second end portions 251 and 252 the uprights 250 are transversely connected together by a pair of elastically deformable cross-bars 290 arranged parallel and spaced relative to each other and perpendicular to the first sides 16 of the second plate body 11.

[0061] Each cross-bar 290 is provided in the middle with a second tooth 300 which is arranged perpendicularly relative to the first teeth 20 and which projects out from the crossbar 290 both towards the first and second end portions 251 and 252 of the uprights 250 and within a perimetral volume delimited by the uprights 250.

[0062] Each cross-bar 290 is designed to form a plastic hinge which allows a relative rotation of the respective second tooth 300 and the first plate body 7 about an axis A perpendicular to the uprights and to the first sides 16 of the second plate body 11, as seen for the embodiment represented by the device 1.

[0063] In the embodiment lb, however, the second teeth 300 are oriented obliquely to each other, having first ends 301 projecting towards the first end portions 251 of the uprights 250 and diverging from each other and second ends 302 projecting towards the second end portions 252 of the uprights 250 and converging towards each other.

[0064] The second ends 302 of the second teeth 300 are spaced apart from each other and are provided with a hook end portion 303; in fact, the second teeth 300 are configured to snap-engage the threaded stud 100 of a second mechanical element 3 to be connected to the first mechanical element 2.

[0065] The first end portion 251 of the uprights 250 and the respective first ends 301 of the second teeth 300 are configured so as to be received inside the second through- perforation 14 when the articulated arms 15 are in the folded-up configuration.

[0066] Moreover, the first ends 301 of the second teeth 300 are delimited, in a direction perpendicular to the first sides 16 of the second plate body 11, between a first flat surface 380 and a second flat surface 390, both oblique with respect to the first and second plate bodies 7, 11.

[0067] The first flat oblique surface 380 of each second tooth 300 is directed towards the inside of the first through-perforation 10 and in this embodiment delimits, together with the first end portions 251 of the uprights 250, the stacking reception seat 40 for another identical retaining device lb.

[0068] The second flat oblique surface 390 of each second tooth 300 is situated towards the perimetral edge 33 of the first plate body 7 and is designed to selectively mate with the first flat oblique surface 380 of a corresponding second tooth 300 of another identical retaining device lb.

[0069] Moreover, with reference to figure 15, the second flat oblique surface 390 of each second tooth 300 is designed to cooperate in use with a tool 43b shaped as a fork, to apply to the cross-bars 290 an elastic torsional stress able to cause rotation of the second teeth 300 towards the outside of the first through-perforation 10 to disengage from the threaded stud 100.

[0070] All the aims of the invention are thus achieved.