PRINTED CIRCUIT PROTECTIVE CASE BASE PLATE PROVIDED WITH A RIVET BLANK BORNE BY A VENTILATION FILTER

Abstract

Disclosed is a base plate (1) and the protective case of a printed circuit. The plate includes a ventilation filter (4) and at least one rivet blank (5) projecting from the plate and intended to penetrate the printed circuit and to be deformed for rigidly connecting the printed circuit to the base plate by projecting from a face (1a) of the plate, the filter including at least one ventilation opening (6). The rivet blank is borne by the filter and includes an internal tube (7) passing right through the rivet blank in the projecting direction thereof, the internal tube opening, on one side, onto an end of the rivet blank that projects furthest from the plate while forming the ventilation opening and, on the other side, into the ventilation filter.

Claims

1. Base plate (1) for a protective case (2) of a printed circuit (3), the plate (1) including a ventilation filter (4) and at least one rivet blank (5) projecting from the plate (1), said at least one rivet blank (5) being intended to penetrate the printed circuit (3) and to be deformed for rigidly connecting the printed circuit (3) to the base plate (1) by projecting from a face (1a) of the plate (1), the ventilation filter (4) including at least one ventilation opening (6), wherein said at least one rivet blank (5) is borne by the ventilation filter (4) and includes an internal tube (7) passing right through said at least one rivet blank (5) in the projecting direction thereof, the internal tube (7) opening, on one side, onto an end of said at least one rivet blank (5) projecting furthest from the plate (1) while forming the ventilation opening (6) and, on the other side, into the ventilation filter (4).

2. Base plate (1) according to claim 1, wherein the internal tube (7) opens into a ventilation device (9, 11) internal to a pedestal (8) of the ventilation filter (4), the ventilation device (9, 11) comprising air flow channels (11).

3. Base plate (1) according to claim 2, wherein the pedestal (8) and said at least one rivet blank (5) have been formed as a single piece with the base plate (1), the pedestal (8) being rectangular and bearing at the middle thereof a central member (9) which is part of the ventilation device (9, 11), the air flow channels (11) starting from the central member (9) while being directed towards a respective portion of the contour of the pedestal (8), the pedestal (8) being elevated with respect to the rest of the base plate (1) on the face (1a) of the plate (1) through which said at least one rivet blank (5) projects, the central member (9) and the air flow channels (11) being elevated with respect to the pedestal (8) on the same face (1a) of the plate (1), the air flow channels (11) and the central member (9) forming the ventilation device (9, 11) defining a recessed shape in the pedestal (8) on the face (1b) of the plate (1) opposite the face (1a) through which said at least one rivet blank (5) projects.

4. Base plate (1) according to claim 1, which has at least two rivet blanks (5, 5a), the rivet blank or blanks (5a) other than said at least one rivet blank (5) borne by the ventilation filter (4) being either borne by the ventilation filter (4), or positioned on the base plate (1) outside the ventilation filter (4), or some of them being borne by the ventilation filter (4), the rest of the rivet blanks (5) being positioned on the base plate (1) outside the ventilation filter (4).

5. Base plate (1) according to claim 1, wherein said at least one rivet blank (5) has a cylindrical or conical base (12) extended by a lug (13) which ends by forming a free end of said at least one rivet blank (5).

6. Method of forming at least one rivet blank (5) borne by a ventilation filter (4) on a base plate (1) according to claim 5, wherein the base (12) and the lug (13) of said at least one rivet blank (5) are formed by at least two successive and respective stamping operations.

7. Formation method according to claim 6, wherein the ventilation filter (4) is formed on the base plate (1) by at least three successive stamping operations: a first stamping operation for the simultaneous formation of the central member (9) and of the air flow channels (11) followed by a second and a third stamping operation for the respective formation of the base (12) and then of the lug (13) of said at least one rivet blank (5).

8. Method of riveting a printed circuit (3) on a base plate (1) using at least one rivet blank (5) borne by a ventilation filter (4), said at least one rivet blank (5) being obtained in accordance with a formation method according to claim 6, in which the free end of the lug (13) of said at least one rivet blank (5) is flattened and widened, transforming it into a rivet by pressure exerted from the outside towards the base plate (1) on the free end of the lug (13) against an anvil tool (14) inserted via the internal tube (7) into the lug (13) starting from the base (12), wherein the free end of the lug (13) is bored through prior to or at the same time as the crushing and wherein, after riveting, a membrane (15) covering said at least one rivet is positioned on the face (1b) opposite the face (1a) of the base plate (1) from where said at least one rivet projects.

9. Assembly of a printed circuit (3) and of the protective case (2) thereof, the protective case (2) comprising a hollow housing (19) and a base plate (1), the hollow housing (19) receiving a printed circuit (3) in the interior thereof, the printed circuit (3) being rigidly connected to the base plate (1) of the case (2) by at least one rivet, a wall of the protective case (2) having a cutout receiving a connector (16) electrically linked to the printed circuit (3), wherein the base plate (1) of the assembly is in accordance with claim 1, said at least one rivet blank (5) borne by the ventilation filter (4) having been transformed into at least one rivet, a membrane (15) covering said at least one rivet on the face (1b) opposite the face (1a) from where said at least one rivet projects and wherein the printed circuit (3), in the form of a board bearing electronic components on a first face, has a second face, opposite the first face, applied against or held at a small distance from the base plate (1) with said at least one rivet borne by the ventilation filter (4) penetrating the printed circuit (3) via a portion of the board free of any electronic component on the first face thereof.

10. Assembly according to claim 9, wherein a portion (18) of the base plate (1) is covered locally with a thermal interface material inserted between the base plate (1) and the contour of the second face of the printed circuit (3), and when at least one rivet is positioned on the base plate (1) outside the ventilation filter (4), this rivet is located on a respective area of the portion (18) of the base plate (1) covered locally with the thermal interface material.

11. Base plate (1) according to claim 2, which has at least two rivet blanks (5, 5a), the rivet blank or blanks (5a) other than said at least one rivet blank (5) borne by the ventilation filter (4) being either borne by the ventilation filter (4), or positioned on the base plate (1) outside the ventilation filter (4), or some of them being borne by the ventilation filter (4), the rest of the rivet blanks (5) being positioned on the base plate (1) outside the ventilation filter (4).

12. Base plate (1) according to claim 3, which has at least two rivet blanks (5, 5a), the rivet blank or blanks (5a) other than said at least one rivet blank (5) borne by the ventilation filter (4) being either borne by the ventilation filter (4), or positioned on the base plate (1) outside the ventilation filter (4), or some of them being borne by the ventilation filter (4), the rest of the rivet blanks (5) being positioned on the base plate (1) outside the ventilation filter (4).

13. Base plate (1) according to claim 2, wherein said at least one rivet blank (5) has a cylindrical or conical base (12) extended by a lug (13) which ends by forming a free end of said at least one rivet blank (5).

14. Base plate (1) according to claim 3, wherein said at least one rivet blank (5) has a cylindrical or conical base (12) extended by a lug (13) which ends by forming a free end of said at least one rivet blank (5).

15. Base plate (1) according to claim 4, wherein said at least one rivet blank (5) has a cylindrical or conical base (12) extended by a lug (13) which ends by forming a free end of said at least one rivet blank (5).

16. Method of riveting a printed circuit (3) on a base plate (1) using at least one rivet blank (5) borne by a ventilation filter (4), said at least one rivet blank (5) being obtained in accordance with a formation method according to claim 7, in which the free end of the lug (13) of said at least one rivet blank (5) is flattened and widened, transforming it into a rivet by pressure exerted from the outside towards the base plate (1) on the free end of the lug (13) against an anvil tool (14) inserted via the internal tube (7) into the lug (13) starting from the base (12), wherein the free end of the lug (13) is bored through prior to or at the same time as the crushing and wherein, after riveting, a membrane (15) covering said at least one rivet is positioned on the face (1b) opposite the face (1a) of the base plate (1) from where said at least one rivet projects.

17. Assembly of a printed circuit (3) and of the protective case (2) thereof, the protective case (2) comprising a hollow housing (19) and a base plate (1), the hollow housing (19) receiving a printed circuit (3) in the interior thereof, the printed circuit (3) being rigidly connected to the base plate (1) of the case (2) by at least one rivet, a wall of the protective case (2) having a cutout receiving a connector (16) electrically linked to the printed circuit (3), wherein the base plate (1) of the assembly is in accordance with claim 2, said at least one rivet blank (5) borne by the ventilation filter (4) having been transformed into at least one rivet, a membrane (15) covering said at least one rivet on the face (1b) opposite the face (1a) from where said at least one rivet projects and wherein the printed circuit (3), in the form of a board bearing electronic components on a first face, has a second face, opposite the first face, applied against or held at a small distance from the base plate (1) with said at least one rivet borne by the ventilation filter (4) penetrating the printed circuit (3) via a portion of the board free of any electronic component on the first face thereof.

18. Assembly of a printed circuit (3) and of the protective case (2) thereof, the protective case (2) comprising a hollow housing (19) and a base plate (1), the hollow housing (19) receiving a printed circuit (3) in the interior thereof, the printed circuit (3) being rigidly connected to the base plate (1) of the case (2) by at least one rivet, a wall of the protective case (2) having a cutout receiving a connector (16) electrically linked to the printed circuit (3), wherein the base plate (1) of the assembly is in accordance with claim 3, said at least one rivet blank (5) borne by the ventilation filter (4) having been transformed into at least one rivet, a membrane (15) covering said at least one rivet on the face (1b) opposite the face (1a) from where said at least one rivet projects and wherein the printed circuit (3), in the form of a board bearing electronic components on a first face, has a second face, opposite the first face, applied against or held at a small distance from the base plate (1) with said at least one rivet borne by the ventilation filter (4) penetrating the printed circuit (3) via a portion of the board free of any electronic component on the first face thereof.

19. Assembly of a printed circuit (3) and of the protective case (2) thereof, the protective case (2) comprising a hollow housing (19) and a base plate (1), the hollow housing (19) receiving a printed circuit (3) in the interior thereof, the printed circuit (3) being rigidly connected to the base plate (1) of the case (2) by at least one rivet, a wall of the protective case (2) having a cutout receiving a connector (16) electrically linked to the printed circuit (3), wherein the base plate (1) of the assembly is in accordance with claim 4, said at least one rivet blank (5) borne by the ventilation filter (4) having been transformed into at least one rivet, a membrane (15) covering said at least one rivet on the face (1b) opposite the face (1a) from where said at least one rivet projects and wherein the printed circuit (3), in the form of a board bearing electronic components on a first face, has a second face, opposite the first face, applied against or held at a small distance from the base plate (1) with said at least one rivet borne by the ventilation filter (4) penetrating the printed circuit (3) via a portion of the board free of any electronic component on the first face thereof.

20. Base plate (1) according to claim 10, wherein said at least one rivet blank (5) has a cylindrical or conical base (12) extended by a lug (13) which ends by forming a free end of said at least one rivet blank (5).

Description

BRIEF DESCRIPTION OF THE INVENTION

[0035] Other features, aims and advantages of the present invention will emerge upon reading the following detailed description with reference to the appended drawings given as nonlimiting examples and wherein:

[0036] FIGS. 1 and 2 are schematic representations of respective views of opposite faces of a base plate intended for a protective case for a printed circuit, the face of the base plate of FIG. 1 being intended to be opposite the printed circuit while the face of FIG. 2 is intended to form a portion of the outer contour of the case, the base plate shown in these figures being in accordance with the prior art,

[0037] FIGS. 3 and 4 are schematic representations of respective top and bottom views of a portion of the base plate including a ventilation filter, a rivet blank being incorporated into the ventilation filter, the base plate including such a filter being in accordance with the present invention,

[0038] FIGS. 5 and 6 are schematic representations of a respective section view of two alternative embodiments of a method for riveting a rivet blank borne by a ventilation filter on a printed circuit, the free end of the rivet blank being bored through in these two embodiments in accordance with the present invention,

[0039] FIG. 7 is a schematic representation of a perspective view of a protective case incorporating a printed circuit in the form of an electronic board, the printed circuit being riveted to the base plate, this protective case being in accordance with the present invention when the base plate has a ventilation filter bearing a rivet obtained from a rivet blank shown in FIGS. 3 and 4.

DETAILED DESCRIPTION OF THE INVENTION

[0040] The figures are given as examples and do not limit the invention. They make up schematic representations of principle which are intended to facilitate the understanding of the invention and are not necessarily to the scale of the practical applications. In particular, the dimensions of the various elements illustrated cannot represent reality.

[0041] In the following description, reference is made to all of the figures taken in combination. When reference is made to one or more specific figures, these figures are to be taken in combination with the other figures in order to identify the designated numerical references.

[0042] Referring to all of the figures and particularly to FIGS. 1, 2 and 7, one aspect of the invention relates to a base plate 1 for a protective case 2 of a printed circuit 3, the case 2 and the printed circuit 3 being shown in FIG. 7. This base plate 1 can be removed from the protective case 2, in which instance the base plate 1 has elements for rigid connection with the rest of the case 2 or is an integral part of the protective case 2 or of part of the protective case 2.

[0043] The latter possibility is not preferred since it is more difficult then to mount the printed circuit 3 against the base plate 1. In the instance of a removable base plate 1, the elements for rigid connection of the base plate 1 and of the case 2 can be latching elements for rapid dismounting of the base plate 1 from the case 2.

[0044] Referring more particularly to FIGS. 1 and 2, a base plate 1 according to the prior art is shown. However, the features which will now be described are taken up for a base plate 1 in accordance with the present invention. The base plate 1 shown in these two figures is intended to be riveted to a printed circuit 3 but is shown in the configuration thereof prior to the riveting, only comprising rivet blanks 5a intended to be deformed to become rivets.

[0045] The rivet blank or blanks 5a project from a face 1a of the plate 1 shown in FIG. 1 that is intended to be opposite the printed circuit 3, in a projecting direction which can be perpendicular to the base plate 1. Each rivet blank 5a corresponds to a rivet not yet deformed and therefore in an initial state of the rivet prior to deformation. Each rivet blank 5a is visible on a base plate 1 that is not yet rigidly connected to the printed circuit, as shown in FIG. 1.

[0046] The base plate 1, shown in FIGS. 1 and 2, includes a ventilation filter 4 and three rivet blanks 5a projecting from the plate 1. The base plate 1 can, however, only include a single rivet blank 5a and two or more than three blanks 5a in other embodiments.

[0047] In FIGS. 1 and 2, the three rivet blanks 5a are arranged on a U-shaped elevated portion 18 of the base plate 1, in the middle of the portion 18 and at each end of the U-shaped portion 18, respectively. This elevated portion is intended to face a printed circuit 3 and is called a thermal platform 18 being covered with a thermal interface material inserted between the plate 1 and the printed circuit 3.

[0048] The rivet blanks 5a shown in FIGS. 1 and 2 will, hereafter, be referred to as outer blanks since they are different to a rivet blank 5 incorporated in a ventilation filter 4 as proposed by the invention, such a blank 5 being particularly shown in FIGS. 3 and 4.

[0049] The ventilation filter 4 of the base plate 1 includes at least one ventilation opening 6. If, in an embodiment, the ventilation filter 4 can contain several ventilation openings 6, in practice it is preferred to have a single ventilation opening 6 which is located in the center of a pedestal 8 of the ventilation filter 4. According to the invention, this ventilation opening 6 will be borne by a rivet blank passing through the ventilation filter at the end thereof projecting furthest from the base plate 1 as will be described in detail later.

[0050] The ventilation filter 4 also includes at least one air flow device 9, 11 connecting with the ventilation opening 6, this device comprising air flow channels 11, one of which is referenced in FIGS. 1 and 2. In a preferred embodiment, there are four air flow channels 11 which meet at the ventilation opening 6. The aim thereof is to direct the air from the inside of the computer, passing via the opening 6 then via the air flow device 9, 11 towards the outside of the computer in the prior art, which will no longer be the case in the present invention, the ventilation opening 6 being borne by the rivet blank at the end thereof which is furthest from the ventilation filter 4, as will be described later.

[0051] The ventilation filter 4 is used for the ventilation of the inside of the protective case 2, particularly for the evacuation of the heat given off by the printed circuit 3 during the operation thereof. In FIGS. 1 and 2, a single ventilation opening 6 which is central to the ventilation filter 4 is shown.

[0052] As can be seen in FIG. 2, a membrane 15 is intended to cover the central member 9. Then, a protective member 20, advantageously in the form of a label, covers the ventilation filter 4 and the membrane 15 on the face 1b of the base plate 1 opposite the face 1a from which the rivet blank or blanks 5a project. The membrane 15 and the protective member 20 are shown spaced from the base plate 1 in FIG. 2. This protective member 20 or label is certified to resist a high-pressure water jet. The high-pressure water jet test is standardized.

[0053] Referring more particularly to FIGS. 3 and 4, showing a ventilation filter 4 in accordance with the present invention, but also to FIGS. 5 and 6 for a better view of the internal tube 7 inside a rivet blank 5 borne by the ventilation filter 4, according to the present invention, at least one rivet blank 5 is borne by the ventilation filter 4.

[0054] The rivet blank 5 borne by the ventilation filter 4 includes an internal tube passing right through it in the projecting direction thereof from the base plate 1. The internal tube 7 opens, on one side, onto an end of the rivet blank 5 that projects furthest from the plate 1 while forming the ventilation opening 6 and, on the other side, into the ventilation filter 4. The internal tube 7 therefore extends over the entire length of the rivet blank 5 borne by the ventilation filter 4, the length of the rivet blank 5 being taken in the projecting direction, this projecting direction being advantageously perpendicular to the plane of the base plate 1.

[0055] Such an internal tube 7 is intended to link the inside of the case containing the printed circuit 3 to the ventilation filter 4 via the ventilation opening 6. It contributes to fully providing the ventilation function that the ventilation filter 4 must carry out, which gives a rivet blank 5 borne by the ventilation filter 4 a second function in addition to the riveting function once deformed.

[0056] The preferred configuration of the present invention is a ventilation filter 4 with an air flow device 9, 11 and a rivet blank 5 starting from a central portion of the ventilation filter 4 in order to project from the base plate 1 with an internal tube 7 extending in the projecting direction, substantially perpendicular to this base plate 1 and ending at the free end thereof furthest from the base plate 1 with the ventilation opening 6.

[0057] However, it is possible within the scope of the present invention to have a rivet blank 5 borne by the ventilation filter 4 that is moved off center with respect to the mid-portion of the ventilation filter 4, this rivet blank 5 having, over the length thereof, an internal tube 7 therethrough which opens out at the base plate 1 onto the ventilation device 9, 11 of the ventilation filter 4.

[0058] The presence of a rivet blank 5 borne by the ventilation filter 4 does not, however, exclude the presence of rivet blanks 5a borne by the base plate 1 outside the ventilation filter 4 as shown in FIGS. 1 and 2 but allows the removal of at least one of these rivet blanks 5a said to be outside the ventilation filter 4.

[0059] Several configurations are possible while being covered by the present invention. In all of the configurations covered by the invention, there is always at least one rivet blank 5 borne by the ventilation filter 4 including an internal tube 7 ending at one end with a ventilation opening 6 and connecting with the ventilation filter 4 at the other end thereof.

[0060] For example, the base plate 1 can include a single rivet blank 5, in which instance the rivet blank 5 is borne by the ventilation filter 4, without another outer rivet blank 5a located on the base plate 1.

[0061] Another configuration provides a base plate 1 provided with several rivet blanks 5, 5a, at least one of which is borne by the ventilation filter 4. In this configuration, there can be several rivet blanks 5 borne by the ventilation filter 4, which are optionally associated with one or more outer rivet blanks 5a located on the base plate 1 outside the ventilation filter 4.

[0062] Some of the rivet blanks 5, 5a can therefore be borne by the ventilation filter 4, wherein this can advantageously be the case when the ventilation filter 4 comprises several ventilation openings 6, the ventilation opening or openings 6 being borne by the free end projecting from the rivet blank or rivet blanks 5. The rest of the so-called outer rivet blanks 5a are then positioned on the base plate 1 outside the ventilation filter 4.

[0063] In the instance of a ventilation filter 4 having several ventilation openings 6, which is not the most frequent configuration, when at least two rivet blanks 5 are borne by the ventilation filter 4, the rivet blanks 5 have an internal tube 7 bearing a ventilation opening 6 at the free end thereof which projects from the plate 1, the other end thereof being linked to the ventilation device 9, 11 borne by the ventilation filter 4. In this instance, the rivet blanks 5 can be borne by the ventilation filter 4 such as to be off center with respect to the mid-portion of the ventilation filter 4.

[0064] An advantageous configuration of the present invention relates to a base plate 1 with a single rivet blank 5 borne by the ventilation filter 4. In this instance, the single rivet blank 5 is arranged in the center of the ventilation filter 4 and connects with the ventilation device 9, 11 which is central to the filter 4.

[0065] Another configuration relates to a base plate 1 comprising one or more outer rivet blanks 5a located on the plate 1 outside the ventilation filter 4 and a rivet blank 5 borne by the ventilation filter 4, which blank is advantageously borne by the mid-area of the ventilation filter 4.

[0066] In order for the respective internal tube 7 of the rivet blank or blanks 5 to have the ventilation opening 6 at the free end of each rivet blank 5 intended to be opposite the printed circuit 3, each free end can be bored through. The boring can be carried out prior to the riveting or during the riveting as will be described in detail later. The other side of the internal tube 7 opens into the ventilation device 9, 11 internal to the pedestal 8 of the ventilation filter 4 via the base 12 thereof.

[0067] Referring more particularly to FIGS. 1-4, the pedestal 8, of rectangular shape, and said at least one rivet blank 5 are formed as a single piece with the base plate 1, therefore in a single unit with the base plate 1. The base plate 1 can be produced by stamping, particularly by successive stamping operations in order to form the various elements present on the base plate 1.

[0068] The pedestal 8 can bear a central member 9 arranged in the middle of the pedestal 8, the central member 9 being advantageously circular. The central member 9 and air flow channels, one of which is referenced 11 in FIGS. 3 and 4, form the air flow device of the ventilation filter 4. The air flow channels 11 can start from the central member 9 while being directed towards a respective portion of the contour of the pedestal 8.

[0069] In a preferred embodiment, the pedestal 8 can be elevated with respect to the rest of the base plate 1 on the face 1a of the plate 1 through which said at least one rivet blank 5 projects.

[0070] Likewise, the central member 9 and the air flow channels 11 forming the ventilation device 9, 11 of the ventilation filter 4 can be elevated with respect to the pedestal 8 on the same face 1a of the plate 1. In this instance, the air flow channels 11 and the central member 9 define a recessed shape in the pedestal 8 on the face 1b of the plate 1 opposite the face 1a through which said at least one rivet blank 5 projects. This is particularly clearly visible in FIG. 4.

[0071] The base plate 1 can be produced by stamping an aluminum sheet for example, wherein the various protrusions on the base plate 1 can be produced by successive stamping operations. It is also possible for the base plate 1 to be manufactured by aluminum casting or plastic molding.

[0072] An advantageous embodiment of the rivet blank 5 borne by the ventilation filter 4 will now be described in detail. Such an embodiment of a rivet blank 5 can be used for a rivet blank 5a on the base plate 1 outside the ventilation filter 4.

[0073] At least one rivet blank 5 borne by the ventilation filter 4 of the base plate 1 can have a cylindrical or conical base 12 connected to the pedestal 8 of the ventilation filter 4. This cylindrical or conical base 12 is extended by a lug 13 which ends by forming a free end of the rivet blank 5 borne by the ventilation filter 4.

[0074] It is via the base 12 of said at least one rivet blank 5 that the internal tube 7 opens into the ventilation device 9, 11 of the ventilation filter 4 via an end, the other end thereof which projects furthest from the base plate 1 bearing the ventilation opening 6. It is also on the base 12 that a membrane 15 will be stuck after riveting.

[0075] The lug 13 points towards the printed circuit 3 at the start of the riveting method in order to be inserted and then deformed in a hollowing arranged in the printed circuit 3, advantageously then in the planar shape of a board bearing various electronic components.

[0076] A method of forming at least one rivet blank 5 borne by a ventilation filter 4 on a base plate 1 as described above will now be described, this method being in accordance with the present invention. In this method, the base 12 and the lug 13 of said at least one rivet blank 5 are formed by at least two successive and respective stamping operations. The first stamping operation forms the conical and cylindrical base 12 while the second stamping operation forms the lug 13.

[0077] The ventilation filter 4 can be formed on the base plate 1 by at least three successive stamping operations: a first stamping operation for the simultaneous formation of the central member 9 and of the air flow channels 11 followed by a second and a third stamping operation for the respective formation of the base 12 and then of the lug 13 of said at least one rivet blank 5. A prior stamping operation to form the pedestal 8 of the ventilation filter 4 can also be implemented.

[0078] With regard to FIGS. 5 and 6 in association with FIGS. 3 and 4, two embodiments of the method for riveting a printed circuit on a base plate 1 using at least one rivet blank 5 borne by a ventilation filter 4 will now be described. The rivet blank or blanks 5 borne by the ventilation filter 4, advantageously a single blank, are obtained in accordance with the formation method as described above with formation of a base and of a lug 13 for the blank 5 or each blank. This has been shown in FIGS. 3 and 4.

[0079] During the riveting, the free end of the lug 13 of said at least one rivet blank 5 is flattened and widened, transforming it into a rivet. The flattening and the widening of the free end of the lug 13 is carried out on the other face of the printed circuit 3 rather than the face orientated towards the base plate 1, the free end of the lug 13 widened in this manner forming an obstacle to the withdrawal of the rivet formed in this manner from the printed circuit 3.

[0080] In the two embodiments shown in FIGS. 5 and 6, the flattening and the widening of the free end of the lug 13 are obtained via pressure exerted from the outside towards the base plate 1 on the free end of the lug 13 against an anvil tool 14 inserted through the internal tube 7 into the lug 13 by starting from the base 12 thereof.

[0081] A tool which is outside the rivet blank 5, called a compression tool 21, presses from the outside on the free end of the lug 13 and crushes it against the anvil tool 14 inside the rivet blank 5. The compression tool 21 can have various profiles, for example a concave profile, a convex profile, an enveloping profile or a flat profile. A flat profile for the compression tool 21 is preferred.

[0082] As can be seen in FIGS. 5 and 6, the length of the anvil tool 14 which has penetrated the rivet blank 5 via the tube 7 is determined in order to correspond to the desired spacing between the base plate 1 and the printed circuit 3 by taking into account the thickness of these two elements.

[0083] At the start of crushing the rivet blank 5, the free end is pushed back towards the anvil tool 14 by the outer compression tool 21. The continuation of the movement of the compression tool 21 towards the base plate 1 causes the flattening and the widening of the free end of the rivet blank 5 pinched between the two tools 14, 21.

[0084] According to features of the invention, the free end of the lug 13 is bored through, advantageously from the inside of the lug 13, prior to or at the same time as the crushing. This allows the internal tube 7 of the rivet blank 5 to open at the free end of the blank 5 by forming the ventilation opening 6 of the ventilation filter 4.

[0085] This can be achieved using a drilling head independent of the anvil tool 14 which penetrates the boring forming the ventilation opening 6 of the rivet blank 5, in this instance prior to the crushing of the free end of the lug 13. Therefore, it is possible to have a base plate 1 with at least one rivet blank 5 passing via the ventilation internal tube 7 for the ventilation filter 4, this rivet blank 5 being already bored through before riveting as shown in FIGS. 3 and 4.

[0086] In FIGS. 5 and 6, the boring is carried out at the same time as the riveting therefore at the crushing of the free end of the rivet blank 5. In FIG. 5, the printed circuit at least partially surrounding the rivet blank 5 is not shown but a portion of the rivet blank 5 passes through this printed circuit before riveting.

[0087] In the embodiment shown in FIG. 5, this can be achieved by the anvil tool 14, the face of this tool 14 opposite the free end bearing a boring tip 14a. This boring tip 14a passes right through the free end of the rivet blank 5 and can be inserted into a housing 22 provided on the opposite face of the compression tool 21 moving from the outside towards the free end of the rivet blank 5 in the direction of the arrow in FIG. 5.

[0088] This housing 22 is optional, wherein the boring can be achieved by a forward movement of the anvil tool 14 inside the rivet blank 5 followed by a withdrawal such that the boring tip 14a is not damaged by the pressure of the compression tool 21.

[0089] In the embodiment shown in FIG. 6, the compression tool 21 has a bush 23 penetrating a hole previously bored in the free end of the rivet blank 5. During the deformation of the rivet blank 5 via crushing, the boring tip 14a of the anvil tool 14 penetrates inside the bush 23 and completes the boring, the bush 23 ensuring that the boring hole does not close over during crushing and protecting the boring tip 14a from the crushing.

[0090] After riveting and withdrawal of the anvil tool 14 from the rivet formed in this manner, still according to the invention, a membrane 15 is positioned on the base 12 of the rivet, this membrane 15 being shown in FIG. 7 spaced from the ventilation filter 4 and from the protective case 2 in order to be more visible. The membrane 15 then covers the rivet on the face 1b of the base plate 1 opposite the face 1a from where said at least one rivet projects.

[0091] FIG. 7 shows an assembly of a printed circuit 3 and of the protective case 2 thereof, wherein this protective case 2 can be in accordance with the present invention when the ventilation filter 4 bears at least one rivet blank 5 which has become a rivet by rigidly connecting the printed circuit 3 to the base plate 1.

[0092] The protective case 2 comprises a hollow housing 19 and a base plate 1. The hollow case 19 receives the printed circuit 3 in the interior thereof, the printed circuit 3 been rigidly connected to the base plate 1 of the case 2 by at least one rivet.

[0093] A wall of the protective case 2 has a cutout receiving a connector 16 electrically linked to the printed circuit 3. The base plate 1 of the assembly is as previously described with at least one rivet passing through the ventilation filter 4 of the base plate 1.

[0094] A membrane 15 covers the base 12 of the rivet of the ventilation filter 4 and said at least one rivet borne by the ventilation filter 4 on the face 1b opposite the face from where said at least one rivet projects. This membrane 15 is a breathable membrane as it allows the passage of air in order to provide the function of the ventilation filter 4. This membrane 15 can be stuck at the center of the ventilation filter 4 on the base of the rivet.

[0095] The printed circuit 3, in the form of a board bearing electronic components on a first face, has a second face opposite the first face applied against or held at a small distance from the base plate 1. During the riveting, said at least one rivet borne by the ventilation filter 4 has penetrated the printed circuit 3 via a portion of the board which is free of any electrical component on the first face thereof.

[0096] Referring in particular to FIGS. 1 and 7, a portion 18 of the base plate 1, previously mentioned as a thermal platform 18, can be covered locally with a thermal interface material inserted between the plate 1 and the printed circuit 3 inserted between the base plate 1 and the contour of the printed circuit 3 second face applied against or held at a small distance from the base plate 1.

[0097] At least one rivet can be positioned on the base plate 1 outside the ventilation filter 4, which is not always the case within the scope of the invention and is in addition to the rivet borne by the ventilation filter 4 which is an essential feature of the present invention.

[0098] The rivet or rivets outside the ventilation filter 4 can be located, as previously mentioned with respect to FIG. 1, on the platform 18 covered locally with the thermal interface material inserted between the plate 1 and the printed circuit 3. The first face of the printed circuit 3, advantageously in the form of a board, opposite the base plate 1, cannot bear electronic components on portions of the first face corresponding to portions of the second face opposite the base plate 1 and which are covered with the thermal interface material inserted between the plate 1 and the printed circuit 3. It is therefore possible for the rivets to pass through the base plate 1 on these portions.

[0099] The ventilation filter 4 can comprise a protective member 20 entirely covering the pedestal 8 of the filter 4 on a face 1b of the plate 1 opposite the face 1a through which said at least one rivet blank 5 projects. This protective member 20 is advantageously in the form of a label.

[0100] The case 2 can also have, on an outer face opposite that formed by the base plate 1, an element which has a pedestal with a central member and air flow channels 11 similar to the pedestal 8 of the ventilation filter 4, this element not being invisible in the figures. This element of the case 2 can also be covered with a protective member, also not visible in the figures, advantageously in the form of a label and is for the attention of the user of the case 2.

[0101] As another additional feature, the case 2 can have a sealing member between the housing thereof and the face of the connector 16 opposite the housing, this connector 16 being electrically linked to the printed circuit 3. The sealing element extends between the housing and the base plate 1 while resting against the base plate 1.

[0102] The edge of the connector 16 orientated towards the base plate 1 can have a sealing bar between the connector 16 and the base plate 1.

[0103] The present invention can be used for all of the electronic cases 2 provided with a ventilation filter 4 and with a base plate 1 including at least one rivet blank 5 intended to become a rivet for holding a printed circuit 3 with respect to the base plate 1. This protective case 2 and printed circuit 3 assembly can form a computer, advantageously, but not limited to, a computer on board a motor vehicle.