Intermediate compensation system to dampen the recoil of a firearm

Abstract

An intermediate compensation system for compensating and dampening the recoil of a firearm fitted with a stock, comprising a primary element (1) made of a flexible, deformable, and elastic material, and a secondary element (2) having a plurality of recesses (8) opening into and at the bottom of the primary element (1) to form a support surface for a user's shoulder, the recesses (8) of the secondary element having varying dimensions and / or densities. The intermediate compensation system is particularly intended to reduce the undesirable effects caused by the recoil of a firearm fitted with a stock on which it is installed. Abstract Figure: Figure 6

Description

Description Title of the invention: Intermediate compensation system for cushion the recoil of a firearm Technical field

[0001] — The present invention relates to an intermediate compensation system to compensate for and cushion the recoil of a firearm.

[0002] — The invention finds a preferred application for compensating and cushioning recoil of a rifle with a stock used as a reaction support on the shoulder of the user of the firearm. Prior art

[0003] — As is known, the recoil of a firearm is caused by reaction forces more or less violent when the ammunition is fired and the projectile, as by example a bullet, comes out of the barrel of the firearm under the effect of the chemical reaction and of the pyrotechnic effect of the powder contained in the ammunition case when said munition is struck, this pyrotechnic effect causing very strong pressure in the socket and therefore on the rear of the bullet crimped on the end of the cartridge case, said pressure allowing the projectile to be violently ejected from the cartridge case of the ammunition and the gun in the direction of a target.

[0004] The recoil of a firearm causes discomfort because of the reaction between the butt of the firearm and the shooter's shoulder. This reaction can cause shock, bruises and other trauma. Moreover, this discomfort is anticipated by the shooter which causes less accurate shooting. These injuries caused by the recoil and the reaction of the butt on the shooter's shoulder can be repeated during shooting exercises.

[0005] Large caliber weapons increase this discomfort and the trauma caused. Studies in the field of osteopathy have shown that shooting with firearms, and especially shooting with a rifle equipped with a stock, has an influence on the articulation sternoclavicular, on which the firearm rests, especially the stock. It is known that the collarbone serves as a bumper in case of a bad hit when firing a firearm. On the other hand, according to these studies, shooting-related pain is particularly pain in the shoulder, cervical, spine, upper limbs, including contractures of the levator scapula and scalene contractures. These pains can lead to to osteoarticular pathologies such as osteoarthritis.

[0006] — These studies have shown that among military personnel, shooting with firearms can induce lesions on the shoulder such as posterior shoulder instability, which can affect the sternoclavicular joint.

[0007] — There are systems to mitigate the effects of weapon recoil when firing. and these systems are based on the use of elastic materials. Soft elastomer materials can be used but have a limited duration of effectiveness and modify the interaction with the shooter's clothing at the shoulder level on which the stock of the firearm rests. With harder materials, called "stock extensions" but less effective, the shooter can more easily reposition the stock of his firearm on his shoulder. The adverse effects of firearm recoil depend on several factors, such as the shooter's morphology, his clothing and in particular the part located at the shooter's shoulders, the type of firearm and in particular the force of the recoil when fired, and the intensity of repeated shots. In certain conditions, a known device may reduce discomfort but will not be properly adapted to other shooting conditions, given the many influencing factors. According to US patent 8,904,692 B2, one solution consists of an assembly of parts including in particular a shock-absorbing pad made of elastomeric material such as natural rubber. Patent EP 3 067 654 B1 describes a recoil damping system comprising a pad made of elastomeric material, in contact with the shoulder of the user of the firearm such as a rifle, a movable element capable of sliding in a direction substantially aligned with the direction of fire, guide elements for this sliding element, structural dampers preferably made of elastomeric materials, positioned in a sandwich between the movable element and a base receiving the pad and the stock of the firearm. However, this device is very complex and the number of its components makes its manufacturing cost very expensive. It is also known from document US 2021 / 0025669 A | to propose a mass / spring / damper type device incorporated in the stock of a firearm, the mass of the device serving as the main absorber of recoil energy when firing the firearm. However, this relatively complex device is installed in the stock of the firearm, which limits its application. US Patent 10,663,252 B1 proposes a device comprising at least two shock absorber systems based on elastomer elements, sandwiched between the stock of the firearm and a pad. However, this device cannot adapt to every type of firearm stock and must be designed specifically in relation to the geometry of the stock receiving the device. The state of the art can also be illustrated by document US 2018 / 026 6787 A1 which proposes a device comprising at least one shock absorber of the two-stage spring cylinder type, aligned substantially in the direction of the barrel of the firearm. This shock absorber cooperates with a base forming a pad thanks to an actuating rod of said cylinder. This device is however complex and not very suitable for several stock geometries. Generally speaking, in the state of the art, shock absorbers are complex and expensive to produce, and often require specific adjustments to the stock of the firearm to accommodate them. It is particularly common for a large part of the stock to be an integral part of the shock absorbers. On the other hand, the known shock-absorbing devices of the state of the art do not allow the recoil reaction forces to be distributed over the shoulder of the user of the firearm in such a way as to limit the tilting movements of the firearm, to allow the user of the firearm to reposition himself quickly and stably in a shooting position adjusted to the target to be reached. In other words, the state of the prior art highlights numerous drawbacks in terms of adaptation to existing firearm stocks, or complex and expensive technological solutions, or solutions which do not allow the force of the recoil of the firearm to be distributed over the shooter's shoulder in such a way as to limit, on the one hand, the unwanted movements of the firearm during a shot, unwanted movements which reduce the shooter's effectiveness in quickly reaching his target during the next shot, and on the other hand to limit the effects of the shock caused by said recoil forces on the shoulder of the user of the firearm, effects resulting in trauma and in anticipation of these traumas which affect the ability to fire accurately towards the target during a sequence of repetitive shots. Summary of the invention The invention proposes to solve all or part of the aforementioned problems, in particular by providing a device called a "skirt" of a main element and a secondary honeycomb element to dampen and compensate for the recoil of the firearm, the design of which makes it possible to favorably distribute the reaction forces of the recoil of the firearm, with the advantage of no longer having to readjust the weapon in the direction of the target, which is favorable in particular for military and sensitive uses in the field of defense. The secondary element is inserted into the skirt of the main element. Another aim of the invention is to be able to adapt the system with different compensation hardnesses to a large number of existing weapons, without having to make modifications to the stock of the firearm. Finally, the invention is to be able to adapt the intermediate silicone system with different compensation hardnesses, depending on the shooter and his age (male or female), the weapon used, the caliber, the ammunition, the outfit (summer, winter) To this end, the invention proposes a compensation system for compensating and damping the recoil of a firearm fitted with a stock, comprising a main element made of flexible, deformable and elastic material and comprising a base provided for forming a support surface for a shoulder of a user of the firearm and an elastically deformable skirt extending around the periphery of the bottom, and a secondary element made of flexible, deformable and elastic material, arranged inside the main element against its bottom, said secondary element having an internal face intended to come into contact with said bottom and an external face opposite said internal face, said secondary element comprising a plurality of cells opening at least onto the external face and having respective dimensions and surface densities, in which the dimensions and / or the surface densities of the cells are variable on the external face of the secondary element. The main element, made of flexible material, thus forms a deformable "sock" outlet which can be adapted to a large majority of stocks, ending blindly on a solid part (in this case the bottom) whose thickness is delimited by an external surface designed to form a support surface for a shoulder of a user of the firearm. The secondary element, to be inserted into the main element, comprises a plurality of cells whose surface densities or dimensions are variable between different zones of its external face, for example between a right zone and a left zone, between the center and the periphery, between a low zone and a high zone. This specificity makes it possible to compensate for a possible change in direction of the barrel at the time of firing, and offers greater adaptability to the shooter depending on whether he is right-handed or left-handed. Furthermore, the fact that the secondary element is independent of the main element makes it possible to have several secondary elements which have distinct thicknesses and / or distinct dimples. These secondary elements thus allow adaptation to the shooter to provide a better distribution of the reaction forces on the shoulder of the user of the firearm, such as a rifle equipped with a stock, and consequently an attenuation of the reaction movements of the firearm during a shot, in particular the upward tilting movement of the barrel of the firearm. In addition, variations in density and / or dimensions of the cells depending on the zones advantageously provide variations in rigidity or flexibility within the secondary element, thus contributing to a measured and controlled distribution of recoil absorption. For the purposes of the invention, the surface density of the cells corresponds to a number of cells per surface unit, such as for example per cm2. In other words, it is possible to have an area with a high density of cells (contributing to greater flexibility of this area) and another area with a low density of cells (contributing to lower flexibility of this other area). It is also possible to play on the hardness (shore) of the material of the secondary element ({shore). Thus, with these two factors (geometric factor defined by the dimensions and surface densities of the cells, and material factor defined by the hardness), the invention allows the shooter (professional or not) to harmonize the recoil of the weapon and the movement of the barrel, and will therefore allow a faster and more precise return to the aiming position towards the target of the firearm. The primary and secondary elements therefore provide comfort and stability in the use of the firearm in the case of repetitive shots. This stability concerns in particular the undesirable phenomenon of the movement of the firearm caused by recoil during a shot, this movement being characterized by the sliding of the stock on the shooter's shoulder, and by the upward tilting movement of the barrel of the firearm. The invention will therefore allow controlled absorption of these parasitic and undesirable movements, thanks to the cells of variable dimensions and / or densities which provide variable behavior to crushing and deformation depending on the areas, and thus reduce the trauma caused in particular on the shooter's shoulder and on his cheek. The secondary element comprises a plurality of cells, for example in the form of a honeycomb. These cells extend in a direction substantially aligned with the firing axis of the firearm, and open freely onto the external face of the secondary element, in contact with the stock. The bottom of the main element (forming a solid part) may be of a constant thickness, or of a variable thickness so as to provide the compensation system with variable behavior in the face of crushing and deformation under the effect of recoil forces when firing the firearm. The external surface of the bottom of the main element can therefore advantageously be of different geometries so as to fit, under the best conditions of comfort and stability of the firearm during a shot, the shoulder of the user of the firearm, while deforming under the effect of recoil forces. This shape can be substantially rectilinear according to a view perpendicular to the plane of symmetry of the stock of the firearm, or be concave or convex. On the other hand, this external shape of the bottom of the main element can be rectilinear, concave or convex according to any cutting plane perpendicular to the plane of symmetry of the stock of the firearm. The parasitic movements are mainly the upward movement of the barrel of the firearm (in other words the barrel rises), the stock resting on the shooter's shoulder and this support forming a sort of pivot connection, this upward movement depending on the capacity of the device to absorb the energy of the recoil forces on the one hand, and on the other hand to distribute the recoil force and the deformation of the secondary element of the device according to the invention. On the other hand, each deformable cell contains air and, under the effect of the crushing caused by the recoil forces during a shot, also behaves like a pneumatic shock absorber because the external face on which the cells open is in more or less sealed contact with the external surface of the stock of the firearm. Thus, during the effect of the crushing and deformation of the cells of the secondary element, the air enclosed in each cell seeks to escape through said external face, this substantially turbulent gas flow causing an additional damping effect. According to one possibility, the main element and the secondary element are made from a single piece. In other words, the secondary element is associated with the main element whose skirt allows the main element to be fixed around the external profile of the end of the stock closest to the shoulder of the user of the firearm. This main element linked to the secondary element can be produced during the molding of the main element and the thickness of its flexible skirt allows rapid assembly and under elastic constraints to maintain said main element according to the invention. Alternatively, the primary element and the secondary element are independent. In other words, the primary element is independent of the secondary element. The secondary element is inserted inside the primary element. In other words, the secondary element is slid inside the primary element, which is advantageous for being able to replace the secondary element, while keeping the same primary element. This main element may, for example, comprise an annular-shaped stiffener, produced by molding over the entire periphery of this element, so as to reinforce the resistance to elastic deformation of said main element when it is mounted around the surface of the stock of the firearm and to allow better elastic retention of the main element on the stock of the firearm. Advantageously, the skirt comes in one piece with the bottom. The cells can be blind and only open into the external face of the secondary element, or alternatively the cells can be through and only open into both the external face and the internal face of the secondary element. In a particular embodiment, the dimensions of the cells of the secondary element relate to their depths and / or their sections. In other words, the depths and / or sections of the cells vary according to the zones of the secondary element, thus allowing the crushing behavior to vary. The notion of depth applies in the particular case of cells one-eyed. Reducing the cell sections in a zone amounts to reducing the size of the cells and thus increasing the compressive rigidity of the zone, and conversely increasing the cell sections in a zone amounts to reducing the compressive rigidity and therefore increasing the flexibility of the zone. Similarly, reducing the depths of the cells in a zone amounts to increasing the compressive stiffness of the zone, and conversely increasing the depths of the cells in a zone amounts to reducing the compressive stiffness and therefore increasing the flexibility of the zone. According to one possibility, the secondary element is elongated along a longitudinal axis and has along this longitudinal axis a lower zone and an upper zone, and the densities and / or the dimensions of the cells are different between the lower zone and the upper zone so that the upper zone is elastically less deformable in compression than the lower zone. Thus, the distribution of the cells on the secondary element and their dimensions will be carried out in such a way as to obtain greater crushing resistance on the upper zone of the secondary element than on its lower zone. Thus, the upper zone is less flexible (or more rigid) in compression than the lower zone, which is advantageous for limiting the lifting phenomena of the barrel of the firearm thanks to this variation in flexibility along the longitudinal axis. Thus, the densities and / or dimensions of the cells vary between these two lower and upper zones to address this problem of lifting the barrel during firing. Advantageously, the densities and / or sections and / or depths of the cells increase between the upper zone and the lower zone. Advantageously, the secondary element also has a central zone, interposed between the upper zone and the lower zone along the longitudinal axis, and the densities and / or dimensions of the cells vary between these three zones. Advantageously, the upper zone is elastically less deformable in compression than the central zone, and the central zone is elastically less deformable in compression than the lower zone; thus providing a gradation of flexibility in compression. Thus, the upper zone is less flexible than the central zone, itself less flexible than the lower zone, which is even more advantageous for limiting the lifting phenomena of the firearm barrel thanks to this finer variation in flexibility along the main axis. According to one possibility, the densities and / or sections and / or depths of the alveoli increase between the upper zone and the central zone and also between the central zone and the lower zone. According to one characteristic, the main element is elongated along a longitudinal axis and has two lateral zones, on either side of this longitudinal axis, which are a right lateral zone and a left lateral zone, and in which the densities and / or the dimensions of the cells are different between the right lateral zone and the left lateral zone so that the right lateral zone is elastically less deformable in compression than the left lateral zone, or conversely the left lateral zone is elastically less deformable in compression than the right lateral zone. Thus, the dimensions and / or densities of the alveoli vary between these two lateral zones. Such a right / left asymmetry can be interesting depending on whether the shooter is right-handed or left-handed, to control lateral parasitic movements when shooting. According to one characteristic, the flexible, deformable and elastic material constituting the main element is chosen from a rubber-based elastomer, a polyurethane elastomer, a silicone-based material. According to another characteristic, the flexible, deformable and elastic material constituting the secondary element is chosen from a rubber-based elastomer, a polyurethane elastomer, a silicone-based material. One possibility is that the soft, deformable, and elastic material that makes up the secondary element is a silicone-based material. Indeed, silicone has properties far superior to other elastomers. Silicone, unlike other elastomers, reacts very weakly to heat and cold. Therefore, whether the temperature is negative or positive, the properties of silicone will not affect the effectiveness of the secondary element. Alternatively, the flexible, deformable and elastic material constituting the main element or the secondary element has a Shore A hardness of between 10 and 70 Shore A, and for example between 15 and 50 Shore A. Advantageously, the flexible, deformable and elastic material constituting the main element or the secondary element is a silicone-based material which has a Shore A hardness which is between 10 and 60 Shore A, and for example between 15 and 35 Shore A. Indeed, the choice of this type of silicone-based material is particularly advantageous for the invention. Brief description of the drawings Other characteristics and advantages of the present invention will appear on reading the detailed description below, of non-limiting examples of implementation, made with reference to the appended figures in which: [Fig.1] represents a perspective view of the exterior side of the back of the main element according to the invention: [Fig.2] represents a perspective view of the interior side of a secondary element with cells; [Fig.3] represents a front view of another secondary element with different cells between the top and the bottom of the secondary element, and more precisely with different cells between the top, the center and the bottom, this specificity being adapted to reduce the lifting of the barrel at the time of the shot; [Fig.4] represents a front view of another secondary element with different cells between the left and the right of the secondary element, and more precisely wider cells on the right for greater flexibility in compression and narrower cells on the left for greater rigidity in compression, this specificity being adapted for right-handed shooters; [Fig.5] represents a front view of another secondary element with different cells between the left and the right of the secondary element, and more precisely wider cells on the left for greater flexibility in compression and narrower cells on the right for greater rigidity in compression, this specificity being adapted for left-handed shooters; [Fig.6] represents a sectional view of a compensation system. [Detailed description of several embodiments of the invention] With reference to the figures describing several embodiments of an intermediate compensation system according to the invention, such an intermediate compensation system comprises a main element (1) and a secondary element (2) which can be inserted into the main element (1). This main element (1) is in the form of a sleeve extending in a main insertion direction for insertion around a stock. This main element (1) has a bottom (5), or bottom wall, which is solid and which is elongated along a longitudinal axis, in other words it is longer than it is wide, as can be the free end of a firearm stock. This main element (1) has, along this longitudinal axis, an upper zone (3) corresponding to the upper part of the end of the stock of the firearm, and a lower zone (4) corresponding to the lower part of the end of said stock, this stock not being shown in [Fig.1]. The upper zone (3) is the vertically highest part, when the stock of the firearm equipped with the main element (1) according to the invention is resting on the shoulder of the user of the firearm. As visible in [Fig. 1], the main element (1) also comprises a skirt (6) arranged around the perimeter of the bottom (5) of the main element (1), this skirt (6) being intended to facilitate and maintain the fixing of the main element (1) around the end of the stock of the firearm. The skirt {6) is tubular in shape. The main element (1) is made in one piece from a flexible material, such as a rubber-based elastomer, or a polyurethane elastomer, or more advantageously a silicone-based elastomer. The main element (1) according to the invention being made from a flexible elastic material, it is advantageously deformable and its elastically deformable skirt (6) can easily adapt to the geometry of the end of a firearm stock when mounting the main element (1) on the firearm stock. The thickness and height (or length) of the skirt (6) gives said skirt (6) a certain elastic flexibility so as to facilitate the mounting of the main element (1) around the end of a firearm stock, while allowing the main element (1) to be held around said stock once installed in the manner of a sock, the skirt (6) covering the external surface of the end of the firearm stock, while adapting in a deformable and elastic manner to the covering surface of said stock, until the secondary element (2), in which cells (8) open out, comes into contact with the surface of the stock. As seen in [Fig.2], the secondary element (2) has an external face (7) which, once the secondary element (2) is inside the main element (1), forms the face on which the stock rests. The secondary element (2) also has an internal face, opposite the external face, which rests against the bottom (5) of the main element (1). The secondary element (2) also has a peripheral face which extends between the external face (7) and the internal face, this peripheral face being surrounded by the skirt (6). The secondary element (2) comprises a plurality of cells (8) which open into the external face (7) and which can either be blind and not open into the internal face, or be through and also open into the internal face. These cells (6) can for example form a honeycomb of the secondary element (2). The cell density (8) can be identical. The thickness of the secondary element (2) can vary between 0.5 cm and 5 cm. The height and width of the secondary element (2) are slightly less than the height and width of the skirt (6) of the main element (1). [Fig.3] represents a front view of a secondary element (2), highlighting the plurality of cells (8) forming a honeycomb, these cells (8) opening onto the external face (7) of the secondary element (2). [Fig.3] also indicates three zones identified (10), (11), (12), these zones separating the secondary element (2) into three parts, zone (10) corresponding to an upper zone of the secondary element (2), zone (12) a central zone, and zone (11) a lower zone, which are distributed along a longitudinal axis of the secondary element (in other words in the direction of its length). The limits of these three zones may correspond, in a non-limiting manner, substantially to one third each of the length of the secondary element (2). Each of these three zones (10), (11), (12) has a specific density of cells (8). This distribution of the three zones can also be chosen differently, depending on the distribution of the deformations of the secondary element (2) under the effect of the recoil forces of the firearm, the secondary element (2) being supported on the bottom (5) of the main element (1) is in reaction with the shoulder of the user of the firearm. This specificity of the three zones (10), (11), (12) with alveoli (8) of different densities, and more specifically the upper zone (10) has a more or less strong density, the central zone (12) has an average density and the lower zone (11) has a low density, allows to reduce the lifting of the barrel when the shot is fired. [Fig.4] represents a front view of another secondary element (2), highlighting the plurality of cells (8) forming a honeycomb, these cells (8) opening onto the external face (7) of the secondary element (2). [Fig.4] also indicates two zones identified (13), (14), these zones separating on either side of its longitudinal axis two lateral zones of the secondary element (2), zone (13) corresponding to the left lateral zone of the secondary element (2) seen from the front, zone (14) corresponding to the right lateral zone of the secondary element (2) seen from the front. The limits of these two lateral zones can correspond, in a non-limiting manner, substantially to one half each in the direction of the width of the secondary element (2). The left lateral zone (13) has firmer cells (8) than the right lateral zone (14). This specificity of [Fig.4] generally corresponds to a right-handed shooter. [Fig.5] represents a front view of a third secondary element (2), highlighting the plurality of cells (8) forming a honeycomb, these cells (8) opening onto the external face (7) of the secondary element (2). [Fig.5] also indicates two zones identified (15), (16), these zones on either side of its longitudinal axis two lateral zones of the secondary element (2), the zone (15) corresponding to the left lateral zone of the secondary element (2) seen from the front, the zone (16) corresponding to the right lateral zone of the secondary element (2) seen from the front. The limits of these two lateral zones can correspond, in a non-limiting manner, substantially to one half each in the direction of the width of the secondary element (2). The right lateral zone (16) has cells (8) firmer than the left lateral zone (15). This specificity of [Fig.5] corresponds as a general rule to a left-handed shooter. It is possible to propose several secondary elements (2) adapted to the needs of each. Thus, the invention also makes it possible to make secondary elements with honeycombs of different hardnesses, geometric shapes, spaces between cells (8). In this non-limiting embodiment, the cells (8) have a hexagonal section, and a variable depth depending on their position. Flexible material separates the cells (8) from each other. These cells (8) can be distributed equidistantly from each other. They can also be distributed unequidistantly. The section of the cells (8) can be of a shape other than hexagonal, such as circular, rectangular, oblong, or of any shape. Cells (8) may also be produced whose cross-section differs depending on the location in the main element (1). The flexible and elastic material constituting the main element (1) and the secondary elements (2), according to the invention, may be made of elastomer, such as, for example, rubber-based elastomers or polyurethane elastomers, and of more or less high Shore A hardness, depending on the desired crushing resistance of the secondary element (2). This Shore A hardness may advantageously be between 30 Shore A and 70 Shore A, and preferably between 10 Shore A and 50 Shore A. Advantageously, this material is mainly based on Silicone, with a hardness of between 10 Shore A and 60 Shore A, and preferably between 15 Shore A and 40 Shore A. The flexible silicone-based material has the advantage of increasing the coefficient of adhesion between the surface (5) of the main element (1) and the shoulder of the user of the firearm, compared to rubber-based elastomer materials, which reduces excessive sliding movements of the stock equipped with the device according to the invention relative to the shoulder of the user of the firearm, movements caused by the effect of recoil during a shot. Another advantage of flexible and elastic silicone-based materials is their low sensitivity to variations in temperature and humidity, so that the mechanical characteristics of these materials remain substantially invariant depending on the conditions of use of the device according to the invention.

Claims

Claims

1. Compensation system for compensating and cushioning the recoil of a firearm fitted with a stock, comprising a main element (1) made of flexible, deformable and elastic material and comprising a bottom (5) provided to form a support surface for a shoulder of a user of the firearm and an elastically deformable skirt (6) and extending around the periphery of the bottom (5), and a secondary element (2) made made of soft, deformable and elastic material, placed inside the main element (1) against its bottom (5), said secondary element (2) having an internal face designed to rest against said base (5) and an external face opposite said internal face, said element se- secondary (2) comprising a plurality of cells (8) opening into the less on the external face and having respective dimensions and respective surface densities, in which the dimensions and / or the surface densities of the cells (8) are variable on the external face of the secondary element (2).

2. A compensation system according to claim 1, wherein the main element (1) and the secondary element (2) are made of a single holding.

3. A compensation system according to claim 1, wherein the main element (1) and the secondary element (2) are independent.

4. Compensation system according to any one of the claims preceding, in which the skirt (6) is made of one material with the bottom (5).

5. Compensation system according to any one of the claims previous, in which the dimensions of the cells (8) of the element se- secondary (2) relate to their depths and / or their sections.

6. Compensation system according to any one of the claims previous, in which the secondary element (2) is elongated according to a longitudinal axis and presents along this longitudinal axis an in- lower (11) and an upper zone (10), and in which the densities and / or the dimensions of the cells (8) are different between the in- lower (10) and the upper zone (11) so that the upper zone (11) is elastically less deformable in compression than the in- lower (10).

7. A compensation system according to any one of the claims previous, in which the secondary element (2) is elongated according to a longitudinal axis and has two lateral zones, on either side of this longitudinal axis, which are a right lateral zone and a zone left lateral, and in which the densities and / or dimensions of the alveoli (8) are different between the right lateral zone and the zone left lateral so that the right lateral area is elastically less deformable in compression than the left lateral zone, or in- pouring the left lateral zone is elastically less deformable in compression than the right lateral zone.

8. A compensation system according to any one of the claims previous, in which the soft, deformable and elastic material constituting the main element (1) is chosen from an elastomer with rubber base, a polyurethane elastomer, a material based on silicone.

9. A compensation system according to any one of the claims previous, in which the soft, deformable and elastic material constituting the secondary element (2) is chosen from an elastomer with rubber base, a polyurethane elastomer, a material based on silicone.

10. A compensation system according to any one of the claims previous, in which the soft, deformable and elastic material constituting the secondary element (2) have a Shore hardness of which is between 10 and 70 Shore A, and for example between 15 and 50 Shore HAS.

11. | A compensation system according to claims 9 and 10, wherein the flexible, deformable and elastic material constituting the element se- condaire (2) is a silicone-based material that has a hardness Shore A which is between 10 and 60 Shore A, and for example between 15 and 35 Shore A.