WO2025045439A1 - Sealing stopper of an opening of a casing protected against electromagnetic fields - Google Patents

Abstract

The invention relates to a stopper for closing, in a liquid-tight and unlockable manner, an opening of a casing, including: - a plug (1) defining an axial direction; - a locking member (2) comprising a body (20) and a threaded rod (21) screwed into the body, the body being secured to the threaded rod by translation in a direction parallel to the axial direction of the plug, the locking member making it possible to pass from an unlocked position, in which the threaded rod (21) is partially unscrewed, to a sealing locked position, in which the threaded rod (21) is screwed into the body (20); and - an electromagnetic protective cap (4) at least partially covering the plug (1) and configured to be in contact with the casing.

Description

Waterproof shutter of a housing orifice protected against electromagnetic fields

[0001] The invention relates to a shutter for closing, in a liquid-tight manner, an orifice of a housing protected against electromagnetic fields. In particular, the housing contains electrical and electronic components, in particular bus bars for connecting electronic circuits contained in the housing.

[0002] When assembling various electronic circuits in metal housings, the housings are assembled together to form a closed case containing all of the circuits, then bus bars are assembled for connecting these circuits. This last operation of assembling the bus bars is carried out using screwdrivers passing through at least one through hole made in a wall of the case. This hole must be reversibly closed to allow access to the inside of the case if necessary, and in a liquid-tight manner, particularly watertight, in order to protect the various elements contained in the case.

[0003] In addition, the housing is insulating from electromagnetic fields, for example it is metallic, the sealing of the orifice must maintain the continuity of this insulation. Indeed, the housing must include electromagnetic protection offering adequate electromagnetic compatibility (EMC) to allow correct operation of the electrical/electronic systems that the housing contains, and without causing harmful electromagnetic disturbances to other surrounding devices.

“Electromagnetic shielding” or “shielding against electromagnetic fields” or “protected against electromagnetic fields” means shielding/protecting against surrounding electromagnetic fields that may interfere with the operation of components in the enclosure or against electromagnetic fields that may be emitted from the contents of the enclosure.

[0004] There are plastic caps comprising a plurality of blades around their circumference which make it possible to close orifices of a container in a relatively sealed manner, however these caps may have insufficient support in the orifices of such a box containing electronic circuits and bus bars. Such a cap is not sufficiently secure against its removal. Furthermore, it is difficult to remove such a cap and to be able to reuse it subsequently. In addition, the plastic does not provide protection from electromagnetic fields.

[0005] An aim of the invention is to provide a shutter capable of closing, reversibly and in a liquid-tight manner, in particular water-tight, an orifice in a wall of a housing, in particular a metal housing, which may contain electrical and electronic components, and which is securely held in this orifice. Another aim is to provide a shutter secured against its manipulation and removal by an unauthorized person. Furthermore, the invention aims to provide a shutter guaranteeing protection against electromagnetic fields.

[0006] For this purpose, the invention provides a shutter for closing, in a liquid-tight, unlockable locked manner, an orifice of a housing, said shutter comprising:

- a plug defining an axial direction,

- a locking member comprising a body and a threaded rod screwing into said body, said body being integral with said threaded rod following a translation in a direction parallel to the axial direction of the plug, said locking member making it possible to move from an unlocked position in which the threaded rod is partially unscrewed to a sealed locked position in which the threaded rod is screwed into the body, and

- an electromagnetic protection cap at least partially covering said plug and configured to be in contact with the housing.

[0007] Advantageously, the electromagnetic protection cap is made of an electrically conductive material. In particular, it is metallic, for example aluminum or steel. Advantageously, said cap comprises at least two shaped lateral tabs, in particular curved, so as to come into contact with the housing, so that permanent contact is ensured between the cap and the housing when the shutter is mounted in a locked position in the orifice, providing permanent electromagnetic protection. In particular, said cap comprises a flange ending in a dropped edge covering the external part of the plug when the shutter is in the orifice to be sealed, said edge being able to come into contact with the external face of the wall of the housing enclosing the orifice. In particular, said tabs extend laterally from the dropped edge.

[0008] Preferably, said body of the locking member is housed in a sealed manner inside the cap. In particular, an internal seal is arranged between the body of the locking member and the inside of the cap.

Preferably, said stopper comprises a hollow interior housing in which houses the body of the locking member.

[0009] Preferably, said plug comprises a peripheral seal. In particular, said seal is positioned in a peripheral groove of the plug and proximal to the part of the plug which is external to the orifice when the shutter is mounted in the locked position in the orifice, the groove being circular, closed on itself, following the periphery of a part of the plug internal to the orifice.

[0010] According to an advantageous embodiment of the invention, the plug comprises a hollow wall portion, elastically deformable, the body of the locking member comprising a portion capable of being force-fitted inside said hollow wall portion in the locked position. The wall of the plug is thus pushed towards the walls of the orifice to retain the plug in the orifice.

Preferably, said elastically deformable hollow wall portion of the plug comprises locking stops capable of blocking the plug in the orifice in the locked position. In particular, said stops project from the outer surface of said elastically deformable hollow wall portion, and during locking, the threaded rod is screwed into the body of the locking member so that the part of said body translates by inserting itself by force and pressing said wall of the plug against the wall delimiting the orifice, the stops coming to grip in this wall delimiting the orifice or coming into abutment under and against the inner face of the housing wall surrounding the orifice, depending on the position of the stops.

[0011] According to a particular embodiment of the invention, the elastically deformable hollow wall portion of the plug comprises blades with a longitudinal direction parallel to the axial direction of the plug. These blades provide flexibility to the wall, making it elastically deformable. In addition, this flexibility can facilitate the insertion of the shutter into the orifice.

For example, the blades, in non-limiting number, are spaced two by two by a cutout in the wall of the cap. In addition, and in particular, blades may include a free edge in excess thickness on its exterior which constitutes a locking stop. [0012] Preferably, the threaded rod of the locking member is secured against unwanted unscrewing manipulation. In particular, the threaded rod comprises a secure head which is manipulated by a dedicated tool reserved for a professional, in particular a professional authorized to work on a housing containing electronic and electrical components.

[0013] Preferably, the stopper and said body of the locking member are made of plastic, for example polyamide (PA), in particular PA 6.6.

[0014] Preferably, the threaded rod is metallic, for example steel or aluminum.

[0015] Preferably, said body of the locking member comprises a central threaded recess receiving the threaded part of said threaded rod.

[0016] In particular, the head of said threaded rod rests on the external surface of the electromagnetic protection cap when the shutter is in the locked position. The threaded rod, in particular its head, contributes to protection against electromagnetic fields.

[0017] The invention also relates to a housing protected against electromagnetic fields, comprising at least one orifice, said orifice being sealed in a sealed, locked and unlockable manner by a shutter as described above.

[0018] Preferably, said housing comprises electronic and electrical components including bus bars, and said bus bars being accessible from said unobstructed orifice.

[0019] In particular, the electrical and electronic components comprise electronic circuits and bus bars for the connections of these electronic circuits.

[0020] Other features and advantages of the invention will emerge from reading the description given below of a particular embodiment of the invention, given for information purposes only but not as a limitation, with reference to the appended drawings in which:

[0021] [Fig. 1] is a perspective view, from below, of a shutter according to one embodiment of the invention.

[0022] [Fig. 2] shows a cross-sectional view of the shutter of Figure 1 in the unlocked position.

[0023] [Fig. 3A] is a top view of the shutter of Figure 1 or 2, positioned in a locked closure in an orifice of a housing.

[0024] [Fig. 3B] is a cross-section of Fig. 3A along plane AA. [0025] [Fig. 3C] is a cross-section of Fig. 3A along plane BB. [0026] In the present description, in order to facilitate understanding of the description of the embodiment of the example, the terms "upper" and "lower" refer to the directions of the shutter inserted into the orifice of a housing along the axis V shown in the figures, regardless of the position of the shutter relative to the housing, the shutter being able to be installed at different locations of the housing. The terms "internal" and "external" refer respectively to the parts of the shutter entering the orifice and to the parts of the shutter remaining outside the orifice, when the shutter is mounted in position locked in the orifice, according to the embodiment of the example. The V axis is oriented from the internal part to the external part of the shutter.

[0027] The axis XX’ of the plug shown in FIGS. 2, 3B, 3C, thus corresponds to the axial direction of the plug of the shutter, and also defines the axial direction of the shutter. The axis V is parallel to this axis XX’.

[0028] The figures will be commented on together.

[0029] According to this example, the shutter according to the invention is intended to reversibly close an orifice of a metal case, made of aluminum according to the example, comprising electronic circuits and bus bars, said orifice being used to pass a part of a screwdriver used to establish the connections of the bus bars.

[0030] Figure 1 shows a shutter according to the invention comprising a plug 1, a locking member 2 comprising a body 20 cooperating with a screw 21, a peripheral seal 3, an internal seal 5, and a protective cap 4 against electromagnetic fields.

[0031] The plug 1 has a cylindrical shape. It is made of plastic, polyamide 6.6 according to the example. It comprises a cylindrical part 10, called the external part, with dimensions greater than those of the orifice of the housing so that this external part 10 of the plug 1 can rest on the external face of the wall 7 of the housing surrounding the orifice (see Fig. 3A-3C). This external part 10 is extended by an internal cylindrical part 10', with dimensions just smaller than those of the orifice so that this internal part 10' of the plug can fit into the orifice. This internal cylindrical part 10' comprises a hollow lower wall part comprising cutouts 101, 102, 103 (the fourth cutout is not visible in the figures) so as to form blades 11, 12, 13, 14, spaced two by two by a cutout. The longitudinal direction of the blades is parallel to the axial direction XX’ of the stopper, and each blade has a free edge 111, 121, 131, 141 in excess thickness on its exterior and whose upper surface is flat. The lower part of the stopper thus has a certain flexibility which makes it elastically deformable. A reduced number of cutouts, therefore blades, are sufficient, thus presenting a certain flexibility.

[0032] The stopper 1 comprises an internal housing receiving the locking member 2. This housing consists of a first hollow part 151 surrounded by said blades 11, 12, 13, 14 and a second hollow part 152 of the stopper above the first. Said hollow parts 151, 152 open into one another.

[0033] A peripheral seal 3 is arranged in a circular groove made around the entire circumference of the plug of the internal part 10' of the stopper, at the limit with the external part 10 of the stopper, in order to ensure the seal against liquids, against water in particular, between the stopper and the inner face of the wall 7 of the housing adjoining it and which delimits the orifice. This seal is also capable of preventing the entry of dust.

[0034] The locking member 2 comprises a body 20 of a shape adapted to be inserted into said internal housing of the stopper from the opening at the base of the stopper.

Said body 20 comprises a truncated cylindrical base 201 with a diameter enabling it to be inserted partly by force inside the bladed wall of the stopper. This base 201 is surmounted by an intermediate cylindrical part 202 with a diameter smaller than that of said base 201. Said intermediate cylindrical part 202 is surmounted by a terminal cylindrical part 203 forming the upper end of said body 20, and with a diameter smaller than that of terminal cylindrical part 203.

Said body 20 comprises a central internal recess 200 which is threaded, extending along the common central axis XX’ of said body 20 and the plug, receiving the threaded part of a screw 21. Said body 20 is integral with said screw 21 following a translation oriented along the axial direction XX’ of the plug.

Said body 20 is made of plastic, polyamide 6.6 according to the example.

[0035] A seal 5 is arranged in a circular groove made around the entire circumference of the terminal cylindrical part 203 of the body of the locking member 2 in order to ensure sealing against liquids, particularly against water, between the inside of the plug 1 and said body 20. This sealing is also capable of preventing the entry of dust.

[0036] An electromagnetic protection cap 4 covers the external surface of the external part 10 of the plug 1. This cap 4 is made of an electrically conductive material, aluminum according to the example. It has the shape of a flange (circular plate) which has a flanged edge 40 coming into contact with the external surface of the metal wall 7 of the housing. However, in order to ensure permanent electrical contact between this cap 4 and the wall of the housing, at least two peripheral tabs 41, 42 are attached laterally to the flanged edge. These tabs 41, 42 are metal blades (made of aluminum according to the example), curved, with a curvature facing the plug 1, such that their free end is in permanent contact with the wall 7 of the housing when the shutter is locked in the orifice of the housing.

[0037] The screw 21 of the locking member 2 passes through this cap 4, in the center of the cap, and the head 210 of the screw 21 comes to bear on the outer surface of said cap 4 when the shutter is locked in the orifice, to hold this cap 4 firmly on the outer surface of the plug and to keep the tabs 41, 42 in contact with the wall of the housing.

[0038] The body 20 of the locking member 2 is held with the plug 1 and the cap 4 by means of the locking screw 21 which is screwed at least partially into the central internal recess 200 of said body 20. [0039] The shutter can occupy a sealed locked position in the orifice and an unlocked position allowing it to be removed from the orifice.

[0040] To close the orifice, the shutter must first be in the unlocked position, as illustrated in FIG. 2, for which the locking screw 21 is only partially screwed into the central inner recess 200 of the locking body 20, the truncated base 201 of the body 20 then being lowered, spacing out in the axial direction XX', slightly from the free edges 111, 121, 131, 141 of the blades 11, 12, 13, 14 of the plug. The entire internal part 10' of the plug 1 is then able to be inserted into the orifice, the blades having sufficient flexibility allowing it to be inserted into the orifice. Once the internal part 10’ of the plug 1 and the body 20 of the locking member are inserted into the orifice, the lower face of the external part 10 of the plug rests on the upper face of the wall of the housing surrounding the orifice.

To lock the plug 1 in a sealed manner in the orifice, the screw 21 is screwed into the body 20 of the locking member so that this body 20 translates upwards inside the plug. The truncated base 201 is positioned in contact with the inner faces of the blades 11, 12, 13, 14 of the plug, the inclined shape of the truncated base 10 is forcibly inserted partly into the hollow shape delimited by said blades by pushing on the edges of the blades, the upper face of the thickened edges 111, 121, 131, 141 which form locking stops coming to be applied under and against the lower face of the housing wall surrounding the orifice, so that the plug 1 is blocked in the orifice as illustrated in FIGS. 3B-3C.

[0041] Furthermore, the curved tabs 41, 42 of the electromagnetic protection cap 4 bear on the housing around the plug, which makes it possible to ground with the metal housing even in the event of irregularities in contact between the fallen edge of the cap and the surface of the housing, and thus ensures permanent protection against electromagnetic fields. The head 210 of the metal screw 21 bearing on the cap 4 also contributes to this electromagnetic protection. [0042] The two seals 3, 5 ensure the watertight closure of the orifice by the shutter.

[0043] To remove the cap 1, it is sufficient to put the shutter in the unlocked position by partially unscrewing the screw 21 to lower the body 20 of the locking member and move it away from between the blades 11, 12, 13, 14 of the cap 1 as explained previously.

[0044] To increase the security of the housing against unwanted opening of the hole, since the electronic and electrical components such as the bus bars must only be accessible to specialized, authorized persons, the screw will have a specific head that can only be handled with a specialized tool. Such a head is not shown in the figures.

[0045] The shutter is quickly mounted in the housing hole in the factory. The shutter is relatively light and economical since the cap and the body of the locking member are made of plastic. Since the shutter includes the sealing gaskets, it avoids having to machine a groove in the wall of the housing to receive a gasket with the risk of losing the gasket.

[0046] The shutter according to the invention makes it possible to close and reopen if necessary an orifice of a housing offering good electromagnetic compatibility, comprising electronic circuits and bus bars, said orifice being used to pass a part of a screwdriver used to establish the connections of the bus bars.

Claims

Claims [Claim 1] Shutter for closing, in a liquid-tight, unlockable locked manner, an orifice of a housing, comprising - a plug (1) defining an axial direction, - a locking member (2) comprising a body (20) and a threaded rod (21) screwing into said body, said body being integral with said threaded rod following a translation in a direction parallel to the axial direction of the plug, said locking member making it possible to move from an unlocked position in which the threaded rod (21) is partially unscrewed to a sealed locked position in which the threaded rod (21) is screwed into the body (20), and - an electromagnetic protection cap (4) at least partially covering said plug (1) and configured to be in contact with the housing. [Claim 2] Shutter according to claim 1, characterized in that said electromagnetic protection cap (4) is made of an electrically conductive material, and preferably said cap comprises at least two tabs (41, 42) shaped so as to come into contact with the housing. [Claim 3] Shutter according to any one of claims 1 to 2, characterized in that said body (20) of the locking member is housed in a sealed manner inside the cap (1). [Claim 4] Shutter according to any one of claims 1 to 3, characterized in that said plug comprises a peripheral seal (3). [Claim 5] A shutter according to any one of claims 1 to 4, characterized in that the plug (1) comprises a hollow wall portion, elastically deformable, the body (20) of the locking member comprising a portion capable of being force-fitted inside said hollow wall portion in the locked position. [Claim 6] Device according to claim 5, characterized in that said elastically deformable hollow wall portion of the plug comprises locking stops (111, 121, 131, 141) capable of blocking the plug (1) in the orifice in the locked position. [Claim 7] Shutter according to one of claims 5 to 6, characterized in that the elastically deformable hollow wall part of the plug comprises blades (11, 12, 13, 14) of longitudinal direction parallel to the axial direction of the plug. [Claim 8] Shutter according to any one of claims 1 to 7, characterized in that the threaded rod (21) of the locking member (2) is secured against unwanted unscrewing manipulation. [Claim 9] Shutter according to claim 8, characterized in that the threaded rod (21) of the locking member (2) comprises a secure head which is handled by a dedicated tool reserved for a professional. [Claim 10] Housing protected against electromagnetic fields, comprising at least one orifice, said orifice being sealed in a sealed, locked and unlockable manner by a shutter according to any one of claims 1 to 9. [Claim 11] A housing according to claim 10, comprising electronic and electrical components including bus bars, and said bus bars being accessible from said unobstructed orifice.