WO2007031611A1

WO2007031611A1 - Damping device with adaptable friction

Info

Publication number: WO2007031611A1
Application number: PCT/FR2005/002290
Authority: WO
Inventors: Guy Valembois
Original assignee: Etienne Lacroix Tous Artifices S.A.
Priority date: 2005-09-15
Filing date: 2005-09-15
Publication date: 2007-03-22

Abstract

The invention concerns a damping device with adaptable friction comprising: at least a pair of assemblies (100; 200) capable of a guided relative movement, one of the two assemblies being connected to a reference, the other being mobile relative thereto, and connecting means (231) between said mobile assembly and the system to be cushioned. Said device is characterized in that it comprises: at least one elastic element (310) having an initial curvature, mounted integral with one of said two assemblies (100; 200) by being prestressed, so as to provide a buckling work and apply a friction force on the other assembly (200; 100) and actuating means (400) adapted to act on said elastic element (310) so as to modify its curvature, thereby modifying said friction force, said actuating means (400) operating under the action of control means (500).

Description

ADAPTABLE FRICTION SHOCK DEVICE

The present invention relates to the field of dampers for mechanical system in motion. The present invention applies in particular, but not exclusively, to the field of weapon systems equipped with a damper device.

It could also apply to the damping of movements and / or shocks between a reference element and a movable element with respect to this reference. Document FR-2 697 881 already discloses a damping device comprising two sets capable of guided relative displacement, one linked to a reference, the other movable with respect to this reference and capable of being connected to a system to be damped.

Such a device also comprises a pad adapted to rest on one of these sets and particularly elastic control means, such as washers, interposed between said pad and the other set. These elastic control means are adapted to exert a force on the shoe tending to apply against the first set during an active phase of biasing the damping device corresponding to a first direction of relative movement between the two sets and reduce the force exerted by the pad during a passive phase of biasing the damping device corresponding to a second direction of relative displacement between the two sets.

In such a device, a relative displacement of the friction surfaces is necessary for the implementation of the friction, which gives a loading response curve of the device in two stages, as illustrated in the attached FIG. damping force obtained E according to the displacement D of the moving assembly.

Phase A corresponds to the initial phase of implementation of the damper and phase B to that of its nominal operation. It can thus be seen that the first phase delays operation and that an initial stroke is necessary before any nominal operation.

In addition, the spring washers used in this device are arranged between a shaft and a bore and act by buckling. These washers, flat at rest, have radial slots opening alternately on the inner periphery. and on the outer periphery. When mounted in the device, they are biased to take a conical geometry.

The initial geometry of this rest position conditions the proper functioning of the damper. It therefore requires a very careful production, which generates very significant manufacturing costs.

Moreover, once the damping device is in phase B of nominal operation, it is found that the pad exerts on the set opposite, a contact pressure and therefore a friction force whose values are constant in time. One possibility to change the value of this friction force is to change the number of spring washers disposed between the pad and one of the sets. However, this supposes to disassemble the damping device.

However, for a given damping device, once in the nominal operating phase it is not possible to have two different damping values.

Finally, the damping obtained with a damping device such as that described in document FR-2 697 881 cited above is related to the direction of movement of one of the two sets.

The present invention aims to overcome these disadvantages. This object is achieved according to the present invention by means of a damping device comprising at least one pair of assemblies capable of guided relative displacement, one of the two sets being linked to a reference, the other being movable relative thereto , and connecting means between said moving assembly and the system to be damped. This device is remarkable in that it comprises elastic means comprising at least one elastic element of curved shape, mounted integral with one of said two assemblies by being prestressed, so as to work in buckling and to apply a friction force on the other together, and actuating means adapted to act on said elastic member to modify its curvature and thus modify said friction force, these actuating means acting under the action of control means.

Preferably, in the context of the invention, the actuating means are adapted to bias said elastic member to reverse its direction of curvature and thereby modify said friction force. According to other advantageous and non-limiting features of the invention, a first embodiment of the device of the invention is proposed:

one of the two sets is a tube and the other comprises an annular ring that is elastically deformable and slidable inside this tube and said elastic element is mounted inside said annular ring so as to exert an stress on its inner wall and to cause its radial deformation and the friction of at least a portion of this ring against the inner surface of said tube;

a friction segment, which takes the place of a friction pad, is interposed between the annular ring and the tube; said actuation means comprise at least one piston capable of moving between a first position called "inactive" in which it does not does not act on said elastic element and a second so-called "active" position in which it exerts a pressure on the convex side of said elastic element when the latter is in a first direction of curvature, so as to deform and if necessary to the bring in its second direction of curvature opposite to the first;

said annular ring is integral with a rod extending axially inside said tube and connected to the reference and / or the system to be damped, and said piston moves axially inside said rod;

said elastic element has the shape of an elongated beam working at buckling;

said control means are pyrotechnic means or electrical means; even mechanical, pneumatic, hydraulic or equivalent. .

- Said actuating means are reversible so as to be able to bias said elastic member to bring it in one direction of curvature or the other. According to other alternative, advantageous and non-limiting features of the invention, a second embodiment of the device of the invention is proposed:

the actuating means are adapted to act on the elastic element (351) so as to reduce said friction force, the device further comprises a third assembly capable of being movable and guided with respect to said reference, in that that said elastic element is also mounted integral with this third assembly, and in that this third assembly is able to be biased by said actuating means, the reference assembly is a tube and said third assembly comprises an annular ring capable of sliding inside this tube, in that said elastic element is mounted integral with said annular ring so as to exert said force on the wall; inside the ring so that it exerts a friction force against the inner surface of said tube,

said ring comprises an annular groove in which the elastic element is mounted,

the device comprises second elastic means in series with said first elastic means, and comprising at least one second elastic element having an initial curvature mounted integral with one of said two sets of the pair of assemblies being prestressed, so as to work buckling and applying a frictional force on the other whole couple,

the device further comprises a fourth assembly capable of being movable and guided with respect to said reference, and in that said second elastic element is also mounted integral with this fourth assembly,

said fourth assembly comprises an annular ring capable of sliding inside said tube, in that said elastic element is mounted on this annular ring so as to exert said force on the inner wall of the ring so that it exerts a frictional force against the inner surface of said tube, - said movable assembly of said pair of assemblies comprises a rod or a central piece of revolution about the axis of said tube, the part being arranged to be connected to the system to be damped, and two annular compartments extending radially from the central piece in the vicinity of the inner wall of the tube, the first and second compartments being arranged to respectively receive said first and second elastic members,

the first compartment has a height greater than the height of said third set, and the second compartment has a height greater than the height of said fourth set, the heights being taken in the direction of the axis of the tube,

the device further comprises an extension of the first compartment housing the first elastic element, to provide a housing for said actuating means,

According to other characteristics common to said two advantageous and nonlimiting embodiments of the invention, is proposed: said actuating means comprise a piston capable of moving between a first so-called "inactive" position and a second so-called "active" position in which, respectively, it does not act and it acts on the deformation of said elastic element; the piston is actuated by fluid pressure, said control means being able to send under pressure a fluid to actuate the piston,

said piston moves axially around said rod,

the rod is provided with a channel for bringing the fluid under pressure to the piston, said control means being electrical means,

said elastic elements have the shape of an elongated beam working at buckling,

- The elastic elements comprise at least one spring washer capable of working buckling, the washer being a star formed of a cone provided with radial cutouts opening alternately on its inner periphery and on its outer periphery.

Finally, the damping device may comprise several pairs of assemblies connected in series or, conversely, connected in parallel.

The invention also relates to an application of the abovementioned damping device to the damping of the force exerted by the recoil of the tube of a firearm.

Other features and advantages of the invention will emerge from the description which will now be made, with reference to the accompanying drawings which represent indicative but not limiting, possible embodiments.

In these drawings: FIG. 1 represents the effort diagram E as a function of the displacement

D, obtained using a damping device of the state of the art;

FIG. 2A represents an elastic element having a curved initial shape, intended to be used in the damping device according to the invention,

FIGS. 2B and 2C show a schematic view of the same elastic element as that of FIG. 2A, after the latter has undergone buckling, respectively in the direction of the initial curvature and against the direction of this initial curvature;

FIGS. 3 and 4 respectively represent the displacement diagram D as a function of time t and the stress diagram E as a function of time t, obtained at using the damping device according to the invention, without activation of the actuating means of this device;

FIGS. 5 and 6 respectively represent the same diagrams as those of FIGS. 3 and 4 but with activation of the actuating means; FIG. 7 represents a diagrammatic view in longitudinal axial section of a damping device according to a first embodiment of FIG. embodiment of the present invention, the actuating means being in the inactive position;

- Figure 8 shows a schematic enlarged view in partial longitudinal axial section of the same embodiment of the damping device, the actuating means being this time in the active position;

FIG. 9 represents a schematic view in longitudinal axial section of a variant of the damping device according to the first embodiment of the invention,

FIGS. 10 and 11 are respectively diagrammatic views in longitudinal axial section of damping devices according to other variants of damping assemblies comprising damping devices according to the first embodiment of the present invention,

FIG. 12 represents a schematic view in longitudinal axial section of a damping device according to a second embodiment of the present invention, the actuating means being in an inactive position and the elastic means being not or only slightly constrained,

FIG. 13 represents a diagrammatic view in longitudinal axial section of the same damping device according to the second embodiment, the actuating means being in the inactive position and the elastic means being constrained,

FIG. 14 represents a schematic view in longitudinal axial section of the same damping device according to the second embodiment, the actuating means being in the active position and elastic means being constrained,

FIG. 15 represents a more general schematic view, in longitudinal axial section, of a damping device according to the second embodiment of the present invention,

- Figure 16 shows a resilient type washer element able to be constrained by buckling.

All the dampers according to the present invention comprise: at least one pair of assemblies capable of guided relative displacement, one of the two sets being linked to a reference, the other being mobile with respect thereto, and

connecting means between said mobile assembly and a system to be damped.

With reference to FIGS. 2 to 11, a first embodiment of the invention will firstly be described.

With reference to FIGS. 12 to 16, a second embodiment of the invention will next be described. We will first describe the first embodiment of damper according to the present invention, illustrated in Figures 7 and 8.

This damping device comprises two sets 100, 200 capable of relative displacement guided in translation along an axis X-X ', elastic means 300 and actuating means 400 acting under the action of control means 500.

In the following description, it will be assumed that the assembly 100 constitutes a support piece, while the assembly 200 is movable and designed to be connected to the system to be damped.

However, this provision should not be considered as limiting. Indeed, other arrangements are possible, for example the reverse arrangement in which the element 100 is movable and connected to the system to be damped, while the assembly 200 is integral with the reference.

As will be seen later, in some provisions the reference can also be mobile with respect to a fixed reference. The assembly 100 is formed of a cylindrical tube centered on the axis X-X 'whose inner diameter is constant over its entire length.

This tube 100 is partially closed at at least one of its ends by a bottom 110 pierced with a central orifice 111 of axis X-X '. This orifice 111 serves as a guide means in translation of the assembly 200 as will be described later.

The tube 100 can also be closed at its opposite end by a wall 120.

The assembly 200 comprises a rod 230 of axis XX ', one of its ends referenced 232 protrudes out of the bottom 110 of the tube 100 and whose end opposite 233 supports a flange 220 generally flat, perpendicular to the axis X-X '. This flange 220 is extended in the opposite direction to the bottom 110 by a ring 210 centered on the axis XX ¹ .

The assembly 200 and more precisely the rod 230 may be attached to an element to be damped by any appropriate means, for example by means of a thread 231 provided on the outer surface of the end 232 of this rod.

In addition, the rod 230 is guided in translation relative to the assembly 100, by any suitable known means and in particular by the orifice 111 formed in the bottom 110 of the tube 100. For this purpose, the outer diameter of the rod 230 is complementary to the inside diameter of the orifice 111.

The ring 210 has two annular portions, namely a portion 211 called "back" integral with the flange 220 and a portion 212, called "before".

The rear portion 211 has been machined over the entire circumference of its outer surface so as to have a smaller diameter than the inside diameter of the tube 100.

In addition, in longitudinal section, this portion 211 has a relatively small thickness so that it is likely to deform elastically as will be explained later.

The front portion 212 is provided on its inner surface with an annular groove 213 whose function will be specified later.

The outer diameter of the front portion 212 of the ring 210 is complementary to the inner diameter of the tube 100, so that the ring 210 is guided in translation inside said tube.

When the elastic means 300 to be described later are mounted inside the annular groove 213, they have the effect of exerting a radial pressure on the portion 212 of the ring 210 which then constitutes a pad rubbing against the inner surface 101 of the tube 100.

The shoe 212 and the tube 100 are advantageously formed based on any suitable friction materials. If necessary, an additional friction pad may be inserted between the means 212 and the tube 100.

For this purpose, all pairs of materials having a high coefficient of friction can be used in the context of the present invention. By way of example, mention may be made of the following pairs: - steel and alumina,

- steel and composite friction materials,

- carbon on itself or on steel,

- graphite on itself or on steel, - steel on sintered friction materials,

- steel on the cast iron,

any other pair of materials that are of interest for friction, in particular ceramics or organic materials.

According to a first variant embodiment, the assembly 200 and the tube 100 consist entirely of the abovementioned friction materials.

In a second variant, only the outer surface of the pad 212 and the inner surface 101 of the tube 100 are covered with a layer of these friction materials.

The elastic means 300 comprise at least one elastic element 310 intended to work in buckling.

This element may be in the form of a slender beam whose length is significantly greater than its thickness, or a spring washer as illustrated in Figure 16 (and discussed below).

This element is advantageously made of steel, or any equivalent spring material, for example bronze or composite material.

The damping device according to the invention can thus rely on a particular property of the buckling of slender structures. This property is illustrated in FIGS. 2A to 2C.

As illustrated in FIG. 2A, a slender elastic element 310 such as one of those used in the damping device according to the invention has an initial curvature able to predefine its direction of deformation when it will be subjected to buckling by approaching its two opposite ends.

Such initial curvature reduces the buckling load with respect to the same initially straight slender element. Thus, and as it appears better in FIG. 2B, if the elastic element 310 is urged in the same direction of curvature as that of its initial curvature (shown in dotted lines), the buckling load will be lower than that of origin. On the other hand, as illustrated in FIG. 2C, if the elastic element 310 is forced to deform so as to adopt a direction of curvature opposite to its initial curvature, it can be seen that for the same approximation of its ends, the load buckling is significantly higher. The spring constituted by the elastic element 310 will therefore have two possible responses in force for the same distance between its ends, depending on the direction of its deformation.

It should also be noted that the difference in effort as a function of the deformation direction is directly related to the relative amplitude of the initial deformation. This difference is therefore adjustable by the initial curvature.

The elastic member 310 may in practice be any form compatible with the present invention.

The elastic means 300 generally comprise a stack of elastic elements 310 mounted in the ring 210 so that their ends rest inside the groove 213 and they are all prestressed in a first direction of curvature.

Preferably, this first direction of curvature is in the same direction as that of the initial curvature of the elastic element 310. The reverse is however possible.

The actuating means 400 for biasing the elastic elements 310 to bring them in the direction of reverse curvature are housed in the end 233 of the rod 230.

For this purpose, this end 233 has an axially preferably cylindrical bore of axis X-X 'opening facing elastic elements 310.

This axial bore comprises a central portion 234 called "chamber" which extends in the direction of the left in FIG. 7 by a hole 235 of smaller diameter opening at the end of the rod 230 facing the elements 310.

Furthermore, the chamber 234 extends to the right by a cavity 236 of smaller diameter.

The difference in diameter between the orifice 235 and the chamber 234 defines a shoulder 237.

The actuating means 400 comprise an actuator or piston of generally cylindrical shape of axis XX 'having a body 410 and a head 420 of greater diameter. The piston 400 is disposed inside the rod 230 so that its head 420 is housed in the chamber 234 and a portion of the body 410 protrudes therefrom.

For this purpose, the diameter of the body 410 corresponds to the inside diameter of the opening 235 and that of the head 420 to the inside diameter of the chamber 234.

The piston 400 is thus guided in translation along the axis X-X '.

It can slide between a first position called "inactive" shown in Figure 7, wherein the end of its body 410 is slightly protruding from the orifice 235 of the rod 230 and comes to rest against the convex side of the last elastic member 310 of the stack 300 and a position called "active", shown in Figure 8, wherein the greater part of its body 410 protrudes out of the orifice 235, the head 420 resting at the end of the race against the shoulder 237.

In this active position, the piston 400 exerts a pressure on the elastic elements 310, which has the effect of deforming them to reverse their direction of curvature.

Preferably, this piston acts on the central part of the elastic element 310.

The axial displacement of the piston 400 is activated by the control means 500. According to a first embodiment illustrated in FIGS. 7 and 8, these control means 500 consist of a housed pyrotechnic charge whose initiation is controlled by a device electric not shown in the figures. This pyrotechnic charge is housed in the cavity 236.

According to a second embodiment not shown in the figures, these control means 500 can also be electrical. In this case, for example, the piston 400 is made of a ferromagnetic material and the control means 500 are an electrical winding surrounding it. The electrical activation of this winding then causes the axial displacement of the piston 400.

According to a third embodiment not shown in the figures, these control means 500 can also be fluidic. In this case, a fluid supply channel is provided in the rod 230 to drive the fluid to the piston 400 (this embodiment will be presented in more detail later).

The operation of the damping device which has just been described is essentially as follows. At rest, the elastic elements 310 are mounted prestressed inside the ring 210 in a first direction of curvature, for example in the same direction as that of their initial curvature.

The buckling of the elements 310 generates a radial pressure which is exerted on the inner surface of the pad 212, which then deforms slightly towards the inner surface 101 of the tube 100, thanks to the elasticity of the portion 211. has the effect of generating a friction force on this inner surface 101.

When the assembly 200 connected to the system to be damped moves to the right according to the representation given in FIG. 7, the shoe 212 exerts a constant force on the inner wall 101 of the tube 100 and this, from the moment tO where the moving this assembly 200, as shown in Figures 3 and 4.

This frictional force tends to slow down the movement of the assembly 200 and makes it possible to dampen the displacement of the latter.

When moving the assembly 200 to the left, according to the representation given in FIG. 7, the various parts mentioned above exert the same constant damping force between t1 and t2, as represented in FIGS. 3 and 4.

Independently of the time and direction of movement of the element

200 relative to the tube 100, it is possible to act on the control means 500 so that they activate the piston 400 according to predetermined parameters. The activation of the piston 400 causes its sliding to the left, according to the representation given in Figures 7 and 8, which has the effect of causing the inversion of the direction of curvature of the elastic elements 310. As explained previously in connection with Figure 2C, the elastic elements 310 are then in a direction of curvature opposite their initial curvature so that the buckling load is higher and the frictional force exerted by the pad 212 on the tube 101 is higher than before the activation of the control means 500.

The braking of the stroke of the element 200 relative to the element 100 and therefore its damping is greater.

This effect is illustrated in FIGS. 5 and 6. The damping device can be designed so that the control means 500 activate the actuating means 400 before any displacement of the element 200 or as soon as the element 200 has traveled a part of its stroke, so as to achieve a modified damping, or even progressive during a complete race of the rod 230. A second embodiment of the present invention shown in FIG. 9 will now be described.

There are sets 100 and 200 capable of relative translation and resilient means 300. However, according to this embodiment, the actuating means of the elastic elements 300 are reversible.

For this purpose, the element 200 comprises a second flange 220 'parallel to the first, disposed opposite it on the other side of the elastic elements 300.

This second flange 220 'is made integral with the ring 210 by an annular portion 211' elastically deformable of the same diameter as the portion 211. This second flange 220 'also has in its central portion actuating means 400' housed in a chamber 234 'opening facing the elastic elements 310 by an orifice 235' and control means 500 ', for example a pyrotechnic charge housed in a cavity 236'. The structure and operation of the actuating means 400 'and the control means 500' are identical to what has been described for the actuating means 400 and the control means 500.

In this embodiment, the element 200 has, with the exception of the rod 230, a symmetrical structure with respect to a vertical plane represented by the axis Y-Y ¹ perpendicular to the axis X-X '.

When the elastic elements 310 have been brought into the position illustrated in FIGS. 8 and 9 in which they have a direction of curvature opposite to that of their initial curvature, the piston 400 'of such a reversible device can act on their face convex to bring them back to their original position. When the control means 500, 500 'can be activated repeatedly, for example if they are of electrical type, it thus becomes possible to modify alternately the direction of curvature of the elastic elements 310 and to change over time l damping force exerted by the device according to the invention. The control means 500, 500 'can be activated according to any appropriate parameter, for example for a need for dynamic control, shock or other phenomenon. They can be activated beforehand, as a preventive measure, or at the time of the event detected by any appropriate sensor, for example a force or speed sensor. Figure 10 illustrates an embodiment in which two pairs of assemblies 100, 200, 100a, 200a are connected in series.

The structure of each of these sets is identical to that shown in Figure 7 and its description will not be repeated. For purposes of clarification, the constituent elements of the pair of sets placed on the left in FIG. 10 bear the same numerical references plus the letter "a".

The rod 230a of the pair of front assemblies is connected to the wall 120 of the tube 100 by any appropriate fastening means, for example by screwing. For this purpose, this wall 120 is pierced with a threaded orifice 121 inside which is aimed the end of the rod 230a itself provided with a thread 23 la.

In such a device, when the assembly 200 biased by the damping system to which it is connected reaches the end of the stroke (on the left in FIG. 10), it abuts against the wall 120 of the first overall pair which then causes the displacement in axial translation of the tube 100 to the left in the representation of FIG. 10.

This tube 100 is guided in translation by any appropriate means not shown in the figures. It constitutes a mobile reference with respect to the tube 100a which is a fixed reference.

The displacement of the tube 100 then causes the axial displacement to the left of the assembly 200a.

Such series mounting increases the value of the damping obtained, if necessary to have successively different damping efforts.

Finally, FIG. 11 illustrates an embodiment in which two pairs of assemblies 100, 200, 100b, 200b are connected in parallel. The structure of each of these sets is identical to that shown in Figure 7 and its description will not be repeated. For purposes of clarification, the constituent elements of the pair of assemblies placed above in FIG. 11 bear the same numerical references plus the letter "b".

In such a device, the tubes 100 and 100b are secured by any appropriate means and the rods 230 and 230b are also secured, for example by a T-shaped element 600 whose free end is connected to the system to be damped.

Note that it would also be possible to mount series or parallel reversible damping devices such as that shown in Figure 9. The damping devices that have just been described can be the subject of numerous applications.

In particular, but without limitation, they can be used in a firearm to dampen the force exerted by the retreat of the tube of a firearm.

With reference to FIGS. 12 to 16, a second embodiment of a device according to the present invention is described below.

This damping device comprises two sets 100, 200 capable of relative displacement guided in translation along an axis X-X ', first elastic means 350, second elastic means 300, and actuating means 400 acting on the first elastic means 350 under the action of control means 500 and here via a third assembly 600.

However, this provision should not be considered as limiting. Indeed, other arrangements are possible, for example the reverse arrangement in which the element 100 is movable and connected to the system to be damped, while the assembly 200 is integral with the reference. As will be seen later, in some provisions the reference can also be mobile with respect to a fixed reference.

The assembly 100 is formed of a cylindrical tube centered on the axis X-X 'whose inner diameter is constant over its entire length.

The tube 100 may also be closed at its opposite end by a wall 120. The assembly 200 comprises a central part 230 of revolution about an axis X-X ', or rod 230, one of the ends referenced 232 is protruding out of the bottom 110 of the tube 100. The assembly 200 and more precisely the rod 230 may be attached to an element to be damped by any appropriate means, for example by means of a thread 231 provided on the outer surface of the end 232 of this rod.

In addition, the rod 230 is guided in translation relative to the assembly 100, by any suitable known means and in particular by the orifice 111 formed in the bottom 110 of the tube 100. For this purpose, the outer diameter of the end of the rod 230 is complementary to the inside diameter of the orifice 111.

The part of revolution or rod 230 has an opposite end supporting three flanges 220, 240, 250 successively spaced, generally flat and perpendicular to the axis X-X '. The respective facing surfaces 271 and 272 of the flanges 240 and 250 define, with the rod portion 230 separating them, a first annular compartment 270 of height U ₄ . The facing surfaces 261 and 262 respectively of the flanges 220 and 240 define, with the rod portion 230 separating them, a second annular compartment 260 of height h ₅ . These first and second compartments 270-260 are intended to receive respectively said first and second elastic means 350-300.

Each of the rod portions 230 located at each of the compartments 260-270 may have been machined to be able to maintain the resilient means 300-350 at their level regardless of the force of stress exerted on them. Thus, the rod 230 may be provided with an annular groove per compartment, the first being delimited by lateral stops 237-238 (for the first compartment 270) and the second by lateral stops 235-236 (for the second compartment 260 ) to prevent at their level any axial movement of the resilient means 350 and 300. The central flange 240 is extended in the opposite direction to the bottom 110 by a ring 241 centered on the axis X-X ', and outside diameter slightly less than internal diameter of the tube 100. The height of this ring 241 can be provided to define in the compartment 270 a housing for the actuating means 400 so that, once the actuating means 400 placed in this annular housing, the edge 242 of the ring 241 and the upper surface 450 of the actuating means 400 form a single substantially flat surface. The height between this surface and the surface 272 of the outer flange 260 is chosen to be equal to hi.

The device according to the second embodiment of the invention further comprises a first set 700 and a second set 600, generally annular, having respective heights h ₂ and h ₆ which are chosen lower than, respectively, hi and h ₅ .

They comprise, respectively, a first annular ring 710 and a second annular ring 610. The outer diameter of each of the annular rings 610 and 710 is complementary to the inside diameter of the tube 100, so that the rings 610 and 710 are guided in translation to inside of this said tube.

When these sets 700 and 600 are respectively placed in the compartments 270 and 260 around the axis X-X ', and the elastic means 350 and 300 which will be described later are respectively mounted integral within said compartments, the elastic means 350 and 300 then have the respective effects of exerting a radial pressure on the first and second rings 710 and 610, which then constitute pads rubbing against the inner surface 101 of the tube 100.

The pads 710 and 610 and the tube 100 are advantageously formed based on all friction materials such as materials with a high coefficient of friction.

(Such as those previously described in the first embodiment of the invention), with possible features (additional friction pads, assemblies 200, 600, 700 and tube 100 made entirely of friction materials or only outer surface of the rings 610 and 710 and inner surface 101 of the tube 100 covered with a layer of friction materials) such as those mentioned above in the first embodiment of the invention.

The assemblies 700 and 600 further comprise, respectively, stops 720-730 and 620-630 extending generally radially towards the axis XX 'from the respective edges of the rings 710 and 610, thus defining between them (and at the rings), respectively, annular grooves whose functions are substantially identical to the functions of the annular grooves provided in the rod 230 and discussed above.

In addition, the stops 720 and 730 can have inclined inner surfaces, converging away from the axis X-X 'so as to limit the curvature of the elastic means 350 and 300 during their buckling. It can be the same for the stops 620 and 630.

In addition, the stops 620, 630, 720, 730 each have an outer surface to the right of the tube 100 for respectively forming stops with said surfaces 261, 262, the ring 241 -means of actuation 400 and said surface 272, when these contacts are operated.

According to a variant of the second embodiment of the invention (not shown), the assemblies 600 and 700 comprise respective annular rings 610 and 710 which in this case have an internal diameter complementary to the outside diameter of the portion of the central part 230. on which they are intended to be radially constrained by, respectively, the elastic means 300 and 350 secured to the inner surface 101 of the tube 100. The possible abutments 620, 630, 720, 730 can then have in this case inclined inner surfaces, converging towards the axis X-X ', and outer surfaces to the right of the axis X-X'. In addition, in this configuration, the central piece 230 may be a simple tube and the assembly 100 advantageously has at its inner surfaces 101 located in each of the compartments 260 and 270, annular grooves for retaining the elastic means 300 and 350 during efforts, similarly to the annular grooves of the rod 230 illustrated in FIG. 12. This configuration is particularly adapted to the case where the assembly 100 is movable relative to the assembly 200.

Said first and second elastic means 350 and 300 comprise at least, respectively, a first elastic element 351 and a second elastic element 301 intended to work in buckling. With reference to FIG. 16, these elements advantageously each have the shape of a flat elastic washer at rest, having radial slots alternately opening on the inner periphery and on the outer periphery to form a set of radial beams stressed by buckling. These washers are advantageously made of steel. Alternatively, these elastic elements may also be in the form of a slender beam whose length is significantly greater than its thickness, as discussed above. The geometry of the device must then be adapted to its dimensions.

In general, the elastic member 301 or 351 may in practice be any form compatible with the present invention.

Each of the washers 301 and 351, once respectively mounted in the compartment 260 or 270, is then urged by the associated rod portion 230 and the assembly 600 or 700, on which their inner and outer peripheries respectively rest, and then take a generally conical geometric shape, being thus prestressed according to initial curvatures. Indeed, these washers can not leave the annular grooves delimited by stops 620-630 or 720-730. The top of the geometrical cone on which the washers 301-351 rest is directed in the direction opposite to the direction of a shock in order to cause the clamping of the pads 610-710 on the tube 100 in the event of impact and cause the loosening of the pad on the tube 100 in case of return to the initial position (return after the shock).

It should also be noted that the difference in effort as a function of the deformation direction is directly related to the relative amplitude of the initial deformation. This difference is therefore adjustable by the initial curvature. Adjustment of the initial curvature can be achieved by positioning the assemblies 600 and 700 in the compartment. Thus, with reference to FIG. 12, the assembly 600 is positioned so as to leave a space e ₄ with the bottom of the compartment 260 (ie said surface 261) and a space e ₃ with the ceiling of the compartment 260 (ie said surface 262); and the assembly 700 is positioned to leave a space e ₂ with the bottom of the compartment 270 (said surface 271) and a space e \ with the ceiling of the compartment 270 (said surface 272). An initial inclination of the respective elastic means 300 and 350 is thus determined.

The elastic means 300-350 generally comprise a stack of elastic elements 301-351 mounted in the compartments 260-270 so that their ends rest inside the grooves of the stem section 230 and the third set 700 or fourth together 700, and they are all prestressed according to a curvature.

The system is preferably removable to allow to change the 300-350 spring washers in case of deficiency thereof.

The actuating means 400 intended to act on the curvatures of the elastic elements 351 to modify them, via the assembly 700, are housed in the housing delimited by the ring 241 provided at the bottom of the compartment 270 and by the rod 230, as seen previously.

For this purpose, the actuating means 400 are of generally cylindrical shape with a diameter substantially close to the inside diameter of the ring 241 and comprise an axial inner recess for engaging the central rod 230 therein. The height of the actuating means 400 is advantageously equal to that of the ring

241.

The actuating means 400 may thus comprise an actuator or piston of the general shape of such a hollow cylinder of axis XX ¹ . The piston 400 is disposed in its housing so that its head 450 is at the same level as the edge 242 of the ring 241.

The piston 400 is thus guided in translation by the rod 230 and retained on the outside by the ring 241 and the tube 100. It can slide between a first position called "inactive" shown in Figures 12 and 13, in which the piston 400 remains in its housing, and an "active" position, shown in Figure 14, wherein it is activated to be guided axially out of its housing, and come into contact with the stop 720 of the assembly 700, in order to act on the deformation of the elastic means 350.

In this active position, the piston 400 exerts a pressure on the assembly 700 such that it forces the latter to move in the tube 100 in a direction substantially parallel to the axis XX 'so as to relieve the pressure exerted on the elastic means 350. In the case where the elastic means are conical washers 351, the force exerted by the piston 400 will be directed at the opposite of the direction of the apex of the geometric cone on which the washers 351 (which is opposite, remember, the direction of a shock in order to cause the clamping of the pad 710 on the tube 100 in case of impact).

In the case where the piston 400 is a fluid piston, such as a hydraulic or pneumatic piston, the rod 230 is provided axially with a channel 800 to bring the fluid under pressure to the piston 400. The axial displacement of the piston 400 is activated by the control means, therefore able to send under pressure a fluid in the channel 800 to actuate the piston 400.

According to an alternative embodiment (not shown in the figures), these control means are electrical. In this case, for example, the piston 400 is made of a ferromagnetic material and the control means are an electrical winding surrounding it. The electrical activation of this winding then causes the axial displacement of the piston 400.

The operation of the damping device which has just been described is essentially as follows.

At rest, with reference to FIG. 12, the actuating means 400 are in the "inactive" position and the elastic elements 351 and 301 are respectively mounted prestressed inside the compartments 270 and 260 respectively according to the first and second curvatures, for example, of the same meaning and of the same value.

This prestressing is chosen relatively low or even zero. The buckling of the elements 300-350 respectively generates a radial pressure exerted on the inner surface of the pads 610 and 710, each then being crushed slightly in the direction of the inner surface 101 of the tube 100. This has the effect of generating a force friction with this inner surface 101. Referring to Figures 13 and 14, is shown the operation of the damping system when the actuating means 400 are respectively in the "inactive" position and in the "active" position.

With reference to FIG. 13, when the assembly 200 connected to the system to be damped moves upwards according to the representation given in FIG. 13, the elastic elements 301 and 351 are stressed in buckling and deformed, the skids

610 and 710 then exert a constant force on the inner wall 101 of the tube 100, a much greater effort than in the "rest" position.

This frictional force tends to slow down the movement of the assembly 200 and makes it possible to dampen the displacement of the latter. The displacement of the assembly 200 may be such that the distances "e ₄ " and

"E _2" become zero, and the distances "e _3" and "Q _\" respectively become equal to or less than about ₍₅ -h h ₆₎ and (1I ₂ -Ii _1).

The displacement of the assembly 200 is thus damped by the elastic means 300 and 350, that is to say by all the elastic means in series of the device. The depreciation can thus be maximum.

With reference to FIG. 14, a first step consists in, of the static state represented by FIG. 12, implementing the actuating means 400 so as to urge the assembly 700 upwards to fill the space " e \ ".

In the case where the elastic means 350 were in a state of prestressing in the rest position, the actuating means can relieve this prestressing.

In the case where the elastic means 350 were in a prestressed state close to zero in the rest position, the actuating means 400 make it possible to reverse the direction of curvature of the elastic means. In all cases, the actuating means 400 act on said elastic member 351 in order to modify its curvature, and thus modify the friction force of the pad 710 on the tube 100: the pressure of the pad 710 against the inner surface 101 of the tube 100 is therefore diminished because of this movement of the assembly 700. In a second step, the assembly 200 connected to the system to be damped is moved upwards, the elastic elements 301 and 351 being then biased.

The second resilient means 300 are stressed in buckling mode and deform identically to the operating mode without activation of the actuating means (FIG. 13 and details above). The shoe 610 then exerts a constant force on the inner wall 101 of the tube 100, a much greater effort than in the "rest" position. This friction force tends to slow down the movement of the assembly 200 and makes it possible to realize T damping of the displacement thereof. The displacement of the assembly 200 may be such that the distance "e ₄ " becomes zero, and the distance "e ₃ " is equal to or less than (h ₅ -h ₆ ).

The first elastic means 350 being in an initial state of stress imposed by the actuating means 400 implemented during the first step, which made it possible to relieve the pressure of the pad 710 against the wall 101 of the tube 100, the displacement of the assembly 200 will allow to approach or even exceed the initial state of prestressing elastic means 350 (preload condition illustrated in Figure 12). To find or exceed the initial state of prestress, the displacement of the set 200 must then be equal to or greater than, respectively, "ei".

In all cases, the pressure of the first pad 710 against the wall 101 of the tube 100 is ultimately less than if said first step had not been implemented.

The damping of the assembly 200 by the elastic means 350 is therefore reduced because of the initial implementation of the actuating means 400, compared to the case where the latter would not have been implemented (compare the operation illustrated in Figure 14 with that shown in Figure 13). The overall damping of the assembly 200 (by elastic means

300 and 350) is therefore reduced because of the initial implementation of the actuating means 400, compared to the case where they were not implemented (compare the operation shown in Figure 14 with that illustrated). in Figure 13). The damping can thus be minimized or maximized depending on whether or not the actuation means 400 are previously implemented or not. It is thus possible to adapt the damping to the value of the force exerted by the system on the assembly. 200. One can also initially play on the space "ej" left between the assembly 700 and the ceiling of the compartment 270 (ie surface 272), to modify the influence of the actuating means 400 on the state of initial stress of the means elastics 350, and thus choose a damping "à la carte". The advantages provided by the actuating means 400 are obtained by a simple hydraulic, pneumatic, electrical or any other adaptable control means.

As a variant of the invention, it will be possible to implement the actuating means subsequent to or simultaneously with the movement of the assembly 200. According to another configuration of the invention, provision may also be made for only the second skate assembly. 600 which is controlled by actuating means 400, and not the first set of shoes 700, or that the two sets of shoes 600 and 700 are controlled by different actuating means 400 placed in each of the compartments 260 and 270, or by a single control means 400 placed in one of the two compartments 260 and 270. More generally, the invention also relates to the case where the device comprises three or more sets of pad 600-700, the number of two sets skate discussed above is of course not limiting. Among these shoe assemblies, one or more of these sets can be controlled by control means 400 according to the invention. Each shoe assembly, associated with at least one elastic element, can be placed within a compartment of its own.

For example, there may be provided a device comprising a set of pad 600 not controlled and three sets of pad 700 ordered, with the following characteristics: - Uncontrolled set: 8 JkN

- Ordered set # 1: 4 kN

- Ordered set # 2: 2 kN

- Ordered set # 3: 1 kN

The devices according to this second embodiment of the invention are reassuring because, in case of failure of the control, all the pad assemblies are in the operating position, the damper then delivering its maximum effort.

In particular, but without limitation, this device can be used in a firearm to dampen the force exerted by the recoil of the barrel of a firearm. fire, this recoil then being transmitted to the central part 230 for a "two-stage" damping according to the second embodiment of the invention.

Claims

An adaptable friction damping device comprising: at least one pair of assemblies (100, 100a, 100b; 200, 200a,

200b) capable of relative guided displacement, one of the two sets being linked to a reference, the other being movable relative thereto, and - connecting means (231, 231a) between said moving assembly and the system to dampen, characterized in that it comprises: resilient means (300, 350) comprising at least one elastic element (310, 310a, 310b, 301, 351) having an initial curvature, mounted integral with one of said two sets (100, 100a, 100b; 200, 200a, 200b) being prestressed, so as to work in buckling and to apply a friction force on the other assembly (200, 200a, 200b; 100, 100a, 100b), and actiomαement means (400, 400 ', 400a, 400b) adapted to act on said elastic element (310, 310a, 310b, 351) in order to modify its curvature and thus modify said friction force, these actuating means ( 400, 400 ', 400a, 400b) acting under the action of control means (500, 500' 500a, 500b).

2. damping device according to claim 1, characterized in that the actuating means (400, 400 ', 400a, 400b) are adapted to act on said elastic element (310, 310a, 310b) to reverse its direction of curvature and thus modify said friction force.

3. damping device according to one of claims 1 or 2, characterized in that one of the two sets is a tube (100, 100a, 100b) and the other comprises an annular ring (210, 210a, 210b) elastically deformable, able to slide inside this tube (100, 100a, 100b) and in that said elastic element (310, 310a, 310b) is mounted inside said annular ring (210, 210a, 210b) so as to exert a force on its inner wall and to cause its radial deformation and the friction of at least a portion (212, 212a, 212b) of this ring (210, 210a, 210b) against the inner surface (101, 101a 101b) of said tube (100, 100a, 100b).

4. damping device according to claim 1 to 3, characterized in that said actuating means (400, 400 ', 400a, 400b) comprise at least one piston capable of moving between a first position called "inactive" in it does not act on said elastic element (310, 310a, 310b) and a second so-called "active" position in which it exerts a pressure on the convex side of said elastic element (310, 310a, 310b) when the latter is in a first direction of curvature, so as to deform and modify its curvature, or to bring it into its second direction of curvature opposite the first.

5. damping device according to claim 3, characterized in that said annular ring (210, 210a, 210b) is integral with a rod (230, 230a, 230b) extending axially inside said tube (100, 100a). , 100b) and related to the reference and / or system to be damped, and in that said piston (400, 400a, 400b) moves axially within said rod (230, 230a, 230b).

6. damping device according to any one of the preceding claims, characterized in that said actuating means (400, 400 ', 400a, 400b) are reversible so as to be able to bias said elastic member (310, 310a, 310b) in a sense of curvature or in the other.

7. damping device according to any one of the preceding claims, characterized in that it comprises several pairs of assemblies (100, 100a, 100b, 200, 200a, 200b) connected in series.

8. damping device according to any one of the preceding claims, characterized in that it comprises several pairs of sets (100, 100a, 100b, 200, 200a, 200b) connected in parallel.

9. damping device according to claim 1, characterized in that the actuating means (400) are adapted to act on the elastic member (351) so as to reduce said frictional force.

10. damping device according to claim 1 or 9, characterized in that it further comprises a third assembly (700) adapted to be movable and guided relative to said reference, in that said elastic element (351) is also mounted integral with this third assembly (700), and in that this third assembly (700) is able to be biased by said actuating means (400).

11. damping device according to the preceding claim, characterized in that an assembly of said pair of assemblies (100, 200) is a tube (100) and said third set (700) comprises an annular ring (710) adapted to slide the along this tube (100), in that said elastic element (351) is mounted integral with said annular ring (710) so as to exert said force on a wall of the ring so that it exerts a friction force against (101) said tube (100).

12. damping device according to the preceding claim, characterized in that said ring comprises an annular groove in which is mounted the elastic member.

13. damping device according to one of claims 9 to 12, characterized in that it comprises second elastic means (300) in series with said first elastic means (350), and comprising at least one second elastic element (301). having an initial curvature integral with one of said two sets of the pair of assemblies (100, 200) being prestressed, so as to work to buckling and to apply a friction force on the other set of torque.

14. damping device according to the preceding claim, characterized in that it further comprises a fourth assembly (600) adapted to be movable and guided relative to said reference, and in that said second elastic element (301) is also mounted in solidarity with this fourth set (600).

15. Damper device according to the preceding claim combined with claim 11 or 12, characterized in that said fourth assembly (600) comprises an annular ring (610) slidable along said tube (100), in that said elastic element (301) is integrally mounted on the annular ring (610) so as to exert a force on a wall of the ring so that it exerts a friction force against (101) said tube (100).

16. damping device according to one of claims 11 to 12 combined with one of claims 14 to 15, characterized in that one set of said pair of sets (100, 200) comprises a rod (230) or a central piece (230) of revolution about the axis of said tube (100), the piece being arranged to be connected to the system to be damped, and two annular compartments (260, 270) extending radially from the central piece (230) in the vicinity of the inner wall (101) of the tube (100), the first and second compartments (270, 260) being arranged to receive respectively said first and second elastic members (351, 301).

17. damping device according to the preceding claim, characterized in that the first compartment (270) has a height greater than the height of said third set (700), and the second compartment (260) has a height greater than the height of said fourth set (600), the heights being taken in the direction of the axis of the tube (100).

18. damping device according to the preceding claim, characterized in that it further comprises an extension of the first compartment (270) housing the first resilient member (351) for providing a housing for said actuating means (400).

19. damping device according to one of the preceding claims, characterized in that said actuating means (400, 400 ', 400a, 400b) comprise a piston capable of moving between a first position called "inactive" and a second position said "active" in which, respectively, it does not act and it acts on the deformation of said elastic member (310, 351).

20. damping device according to the preceding claim combined with one of claims 16, 17 and 18, characterized in that said piston (400, 400a, 400b) moves axially around said central piece (230) in at least one of two compartments.

21. damping device according to one of the two preceding claims, characterized in that the piston is actuated by fluid pressure, said control means being adapted to send under pressure a fluid to actuate the piston.

22. damping device according to the two preceding claims, characterized in that the rod (230) is provided with a channel (800) for bringing the fluid under pressure to the piston (400, 400a, 400b).

23. damping device according to any one of claims 1 to 8, characterized in that said control means (500, 500a, 500b) are pyrotechnic means.

24. damping device according to any one of claims 1 to 20, characterized in that said control means (500, 500a, 500b) are electrical means.

25. damping device according to any one of the preceding claims, characterized in that said elastic elements (310, 310a, 310b, 301, 351) have the shape of an elongated beam working buckling.

26. damping device according to any one of claims 1 to 24, characterized in that the elastic elements (310, 310a, 310b, 301, 351) comprise at least one spring washer capable of working buckling.

27. Device according to the preceding claim, characterized in that the washer is star formed of a cone provided with radial cutouts opening alternately on its inner periphery and on its outer periphery.

28. Application of the damping device or according to any one of the preceding claims, the damping of the force exerted by the retreat of the tube of a firearm.