FR2874070A1 - METHOD FOR MANUFACTURING A DAMPER ELEMENT, SHOCK ABSORBER ELEMENT OBTAINED BY THE METHOD, AND SHOCK ABSORBER DEVICE IMPLEMENTING SAID ELEMENT - Google Patents

Abstract

The method of manufacturing a damping element (4) having a given geometrical configuration consists of: a) forming, by molding, impression, cutting or any other suitable means, a compact block (5) of a gel having said geometric configuration andb) forming on all or part of the outer surface of said block (5) a polymer film (10) by spraying or spraying and cross-linking a crosslinkable dispersion of said polymer.For the manufacture of a damping device (1) serving for supporting an object (11) to be protected from shocks and vibrations, in which the damping element (4) is arranged between a supporting support element (2) of the object (11) to be protected and a support element (3), the spraying or spraying of the dispersion of the crosslinkable polymer takes place on the apparent surface of the block, after it has been put in place on the support element (3) or possibly between the support element (3) and the support member (2).

Description

2874070 1

  METHOD FOR MANUFACTURING A DAMPER ELEMENT, ELEMENT

  DAMPER OBTAINED BY THE METHOD AND DEVICE

  The present invention relates to the field of shock absorption and / or mechanical vibration. BACKGROUND OF THE INVENTION It relates more particularly to a damping element comprising a gel, its manufacturing method and a device implementing it.

  The problems of damping shocks and / or mechanical vibrations arise in many aspects of modern life. By way of example and in a non exclusive way, arises, in the field of aeronautics, the problem of the protection of electronic and computer equipment including the hard drive - boarded an aircraft because of the inherent mechanical effects the use of this aircraft, mechanical effects of the vibration type and also of the shock type, due to the impact during landing or acceleration during takeoff. These problems are all the more important that it is sophisticated electronic or computer equipment equipping including strategic aircraft.

  Among the different damping means that have been developed, cushion-type structures are known, which comprise an envelope inside which damping material is housed. In general, the envelope is made in the form of a thin film of a material with a high coefficient of elongation and high elasticity, while the damping material is chosen so that its creep varies with the pressure exerted. It is in particular known to use a thermoplastic polyurethane material as the casing and as a damping material a silicone gel or the like.

  In FR.A.2.741.683, it explains precisely the technique of manufacturing a cushion-type damping element. It is first of all to make the envelope in the desirable geometry leaving an opening then allowing to introduce into this envelope the mixture of two components under conditions allowing their crosslinking in the form of a gel. It is then a question of closing the envelope in order to seal it.

  In the example described and illustrated in the document FR.A.2.741.683, the damping element is in the form of a case inside which the object to be protected can be housed. This case has the overall shape of a rectangular parallelepiped. This embodiment requires the making, from a thin film, of a first outer envelope and a second inner envelope, the use of templates for maintaining the shape of these two envelopes during the introduction into space free between the two said envelopes of the two-component mixture, and then closing the opening between the two envelopes after crosslinking of the gel.

  In any case, this manufacturing technique which is already very difficult for a fairly simple geometric configuration, prohibits to consider much more complex geometric shapes for the damping element.

  This disadvantage does not exist in the foam-type damping elements which can be adjusted, by cutting, to the shapes of the object to be protected.

  In the document FR.2.831.235, it has already been sought to combine, in the same damping element, the advantage of the manufacturing technique using foam and the advantage of the cushion structure. According to this document, the damping element comprises a foam with open cavities and, injected into said cavities, a second material capable of elastically deforming in said open cavities during a mechanical impact and / or pressure exerted on said element. . It is also expected that this damping element may comprise an outer casing to increase its mechanical strength and prevent contact of the foam and the other material with the object to be protected. This envelope is not necessarily waterproof or perfectly adapted to the configuration of its contents.

  The first object of the present invention is to provide a simplified manufacturing technique for a cushion-type cushioning element, without the need to use a foam as in document FR.2.831.235.

  According to the present invention, the method of manufacturing a damping element having a given geometrical configuration consists of: a) forming by molding, impression, cutting or any other suitable means a compact block of a gel of polymer having said geometric configuration and b) forming on all or part of the outer surface of said block a polymer film by spraying, depositing or spraying and crosslinking a crosslinkable dispersion of said polymer.

  Thus, according to the particular arrangement of the present invention, the outer shell of the damping element is formed directly on the polymer gel, while the latter already has the desired geometrical configuration, homogeneous envelope and perfectly distributed on the outer surface on the dispersion has been sprayed, deposited or projected.

  Preferably the spraying or spraying of the crosslinkable dispersion occurs while the polymer constituting the compact block is not yet fully crosslinked. This gives a better adhesion between the film and the block, after crosslinking of the two polymers respectively of the block and the film.

  The formation of the film on all or part of the outer surface of the block can be done by spraying with nozzle or airIess type spray gun, or by the projection of the curtain type, or even by a simple deposit using a brush.

  The polymer of the crosslinkable dispersion is chosen so that the film obtained after crosslinking is smooth, with a feel that is neither greasy nor sticky, and can provide the gel block with improved mechanical strength.

  The compact block can take all kinds of geometric configuration, for example cubic, parallelepipedic, frustoconical, pyramidal, cylindrical. It may be a solid block or a block having an inner recess. This latter version has the advantage of obtaining, during compression of the block, a double creep of the gel, outwards and towards the inner recess.

  Advantageously, the spraying, depositing or spraying of the crosslinkable dispersion also occurs on the surface of the inner recess.

  This damping element can be implemented in particular in a damping device for supporting the object to be protected from shocks and vibrations.

  In such a damping device, the damping element may have an adhering upper face intended to support the object to be protected from shocks and an adhering lower face serving as a bearing face of the device on, for example, a table, a piece of furniture or generally a structural part. The adherent faces have a tack, that is to say an adhesive capacity, sufficient to ensure the stability of the object relative to the structural part, or the holding in position of the damping element between the object and the structural part. In a particular case of use, the damping element can be used for the protection of two glass plates during their transport, one of the plates acting as object to be protected and the other of structural part.

  In a damping device of another type, the damping element is arranged between a support element and a support element, the support element acting as support for the object to be protected and the support element enabling the support of the device on a structural part.

  In an alternative embodiment, the support element and / or the support element comprises an insert which is included in the compact block of polymer gel during the formation thereof, which makes it possible to obtain a mechanically resistant assembly. For example, the support element and / or the support element may consist of a fixing head, in particular a threaded rod, extending said insert out of the compact block. Of course the object to be protected also includes fastening means capable of cooperating with the fixing head, for example a tapped hole.

  In an alternative embodiment, the support element and / or the support element is a support plate and / or a support plate coming into contact with a flat face of the compact block.

  The spraying, depositing or spraying of the crosslinkable dispersion can be carried out over the entire surface of the block or, in the latter case, it can only be done on the apparent surface of the block, after this has been put in place between the support plate and the support plate.

  However it is desirable that the damping element is integral with the support plates and support. To do this it is possible to apply a layer of binder previously on the contact areas between said plates and the gel block.

  Optionally this binder layer may be constituted by the same crosslinkable dispersion as that used for the formation of the film on the apparent surface of the block. In this case, first of all, a layer of the crosslinkable dispersion is deposited on the backing plate, at least at the level of the contact zone, the block of gel is deposited on said zone, spraying, depositing or spraying the crosslinkable dispersion over the entire visible surface of the elastomer block, then applying the support plate to said block. It is then sufficient to wait until the polymer thus deposited reticle, which on the one hand creates a bond between the block polymer and each of the two plates and on the other hand forms, on the apparent surface of the gel block, a film acting as an envelope. Optionally, if necessary, it is possible to carry out one or more sprays, deposits or additional projections on the apparent surface of the block between the two plates depending on the desired mechanical strength for the film.

  In an alternative embodiment, the compact block of polymer gel has, in vertical section, the shape of an isosceles trapezium, each of the two elements, in particular plates, support and support, being in connection with one of two bases of said trapeze. This particular structural feature is intended to allow the gel block to deform under better conditions on the occasion of a mechanical effect comparable to a shock, in particular due to the acceleration on takeoff of an aircraft or to the impact when landing. If the cross section of the gel block was simply rectangular, the deformation of said block would result in a lateral bending whose vertex would be at the median plane of the gel block, with a risk of rupture of the film constituting the envelope of the block in case of excessive deformation. Because of the trapezoidal section 2874070, the deformation results in a filling of the volume surrounding the block near the small base of the trapezium, possibly with contact of the film on the adjacent plate, which minimizes the risk of tearing of said film .

  In its isosceles trapezoidal section shape, the compact block may have a configuration having a central axis of symmetry, for example frustoconical, pyramidal or regular, or a central plane of symmetry with a longitudinal structure. In a particular embodiment, the device damper comprises two longitudinal blocks of polymer gel, which are distant from each other and whose general direction is parallel.

  The present invention will be better understood on reading the description which will be made of exemplary embodiments of a damping device comprising a support element, a support element and, between said two elements at least one gel block of polymer, integral with said two elements and whose apparent surface is covered with a film obtained by spraying, deposition or spraying of a crosslinkable dispersion, illustrated by the appended drawing in which: FIG. 1 is a schematic representation in perspective of the mold FIG. 2 is a diagrammatic sectional representation of a first example of a damping device comprising two compact blocks of gel obtained with the mold of FIG. 1.

  Figure 3 is a sectional representation of a second example of a damping device comprising two support and support elements, with inserts included in the compact block.

  In the field of aeronautics, manufacturers are increasingly demanding in terms of the protection of electronic or computer equipment against vibrations and shocks that may occur in all phases of flight, particularly the phase of flight. landing where shocks during ground impact may be violent. It is indeed almost vital that the electronic or computer equipment including the hard disk that are embedded are not damaged during the flight. The damping device of the present invention aims particularly but not exclusively to meet these constraints required by the aeronautics.

  The device 1 according to the first example, as shown in Figure 2, comprises a support plate 2, a support plate 3 and, arranged between the two said plates 2, 3, two damping elements 4, 4 '.

  Each damping element 4 comprises on the one hand a compact block 5 of a polymer gel, in particular elastomer, and on the other hand an outer film 6 which covers the compact block 5 on at least the apparent surface of said block 5 when it is positioned between the two plates 2, 3 as illustrated in FIG. 2. In practice, the outer film may also cover the compact block over its entire surface, especially when the polymer of the crosslinkable dispersion is used, as a cohesive agent with the support and / or support plate.

  In the example shown, the compact block 5 has a longitudinal and pyramidal shape, whose cross section is an isosceles trapezium. The upper face 5a of the compact block 5 corresponds to the small base of the trapezium, while the lower face 5b corresponds to the large base of the trapezium.

  The preparation of the compact block 5 is done simply by means of a mold 7 having internally the exact geometrical configuration of the compact block 5, as illustrated in FIG. 1. It is introduced into this mold 7, after having them mixed and optionally degassed, the components for obtaining, after crosslinking, a compact gel of polymer, especially silicone.

  After crosslinking, the compact block 5 is demolded.

  It may be desirable to perform some preparation of the backing plate in order to obtain good adhesion with the compact block, either surface preparation of the sandblasting type or preparation using a binder or a binder. primer 8. The two compact blocks 5, 5 'are arranged on the plate 3 thus prepared so that their bottom faces 5b, 5b' are in contact with the contact zones 3a, 3'a on which deposited the binder layer 8 or primer.

  In this placement, the two compact blocks 5, 5 'are arranged so that they are parallel to each other.

  In the illustrated example, a dispersion of a crosslinkable polymer is then sprayed on the entire apparent surface of the two compact blocks 5, 5 ', namely the upper faces 5a, 5'a but also all the lateral faces. 9, 9 'so as to form, after crosslinking, a film 10 constituting the envelope of the damping element 4, 4'.

  After this spraying and before the crosslinking occurs, the two damping elements 4, 4 'are deposited on the support plate 2, the bottom face 2a of which has optionally been subjected to a sanding treatment.

  At the end of the crosslinking, an adhesion between the damping element 4, 4 and the support plate 2 is obtained.

  A damping device 1 has thus been obtained in which the damping elements 4, 4 'adhere to the two plates 2, 3 and are surrounded by a protective film 10, which acts as an envelope with reference to the known cushion-type structure.

  Depending on the desired mechanical strength for this film, it may be necessary to perform several successive sprays to obtain a film of greater thickness.

  The device 11 of the second example, illustrated in FIG. 3, comprises a support element 12 and a support element 13 which are partly inserted in the damping element 14. More specifically, the support element 13 consists of a threaded rod 12a which is extended by an insert 12b, included inside the compact block 15 of the damping element 14; likewise for the support element 13 with the threaded rod 13a and the insert 13b.

  The polymer gel of the compact block must of course have the desirable characteristics to act as a damping material. Spraying, depositing or spraying of the dispersion is preferably carried out while the crosslinking of the polymer gel is not yet fully achieved.

  The crosslinkable dispersion may be of the cold-crosslinkable type, for example as it is a spray in contact with ambient humidity, or it can be crosslinked with heat.

Claims (10)

  1.Procédé of manufacturing a damper element (4) having a given geometric configuration, characterized in that it consists: a) to form, by molding, impression, cutting or any other suitable means, a compact block (5) a gel having said geometrical configuration and b) forming on all or part of the outer surface of said block (5) a polymer film (10) by spraying or spraying and crosslinking a crosslinkable dispersion of said polymer.   2.Process of manufacturing a damping device (1) serving as support for an object (11) to protect against shocks and vibrations, wherein the damping element obtained by the method of claim 1 is disposed between an element of support acting as support (2) for the object (11) to be protected and a support element (3), characterized in that the spraying or spraying of the dispersion of the crosslinkable polymer takes place on the apparent surface of the block, after that it has been placed on the support element (3) or possibly between the support element (3) and the support element (2).   3.Procédé according to claim 2 characterized in that the support element and / or the lower support element comprises an insert, included in the compact block of polymer gel during the formation thereof.   4.Procédé according to claim 3 characterized in that the support element and / or the lower support element comprises an anchoring portion included in the compact block and a fixing portion protruding from the compact block, for example a rod threaded.   5.Procédé according to claim 4 characterized in that the support member and / or the support member is a plate in contact with a planar face of the damping element.   6.Procédé according to claim 5 characterized in that prior to the placement of the compact block (5) between the plates (2, 3) a layer of binder or primer is applied at least on the support plate 2874070 11 (3) and at least on the contact area between said plate and the compact block (5).   7.Procédé according to claim 6 characterized in that the layer of binder or primer is formed by the same crosslinkable dispersion primer that is used for the formation of the elastomer film (10) on the surface apparent compact block (5). 8. damping device obtained by the method of claim 1 characterized in that the compact block has a frustoconical, pyramidal, cylindrical, cubic or parallelepipedic configuration.   9.Dispositif according to claim 8 characterized in that the compact block comprises an inner recess.   1O.Device according to one of claims 8 or 9 characterized in that the compact block comprises two adherent faces, one support and the other support.   11.Damping device obtained by the method of one of claims 5 to 7 characterized in that the compact block (5) of polymer gel has, in vertical section, the shape of an isosceles trapezium, each of the two plates, support (3) and support (2), being in contact with one of the two bases (5b, 5a) of said trapezium.   12.Dispositif according to claim 11 characterized in that it comprises two longitudinal compact blocks (5,5 ') of elastomer gel, which are spaced apart from each other and whose general direction is parallel.