Mass-market system with elastically deformable wheels

Description

TECHNICAL FIELD

[0001] The invention relates to the field of defense devices intended to protect a vehicle against dangers present in the ground, in particular explosive devices. The invention relates more particularly to a mass decoy system, that is to say a system intended to be coupled to a vehicle to be protected and adapted to exert pressure on the ground, at the front of the vehicle, in order to trigger any explosive devices present on the path of the vehicle to be protected.

[0002] Mass decoy systems generally consist of a chassis coupled to the front of a vehicle to be protected and equipped with a set of wheels to exert pressure on the ground. PRIOR ART

[0003] Anti-personnel and anti-tank mines, improvised explosive devices (IEDs), and generally any type of explosive device triggered by the passage of a vehicle, constitute a threat to vehicles traveling on routes where these explosive devices could be found.

[0004] Mass decoy systems are a means of protecting against this threat. Mass decoy systems are generally installed at the front of a follower vehicle to be protected, and are most often equipped with wheels whose passage over sensors triggers the explosive device.

[0005] The wheels of the mass decoy system are responsible for activating the explosive devices and must be placed as far forward as possible to keep the following vehicle as far away from the location where the decoy explosive device explodes.

[0006] This type of system appeared during the First World War and was developed further during the Second World War.

[0007] More recent developments have improved these systems by replacing metal rollers with juxtapositions of suspended wheels to improve ground tracking during vehicle movement. This has resulted in greater efficiency, at the cost of reduced longevity.

[0008] Prior art mass decoy systems are generally based on the arrangement of automotive or earthmoving wheel sets. Automotive wheel sets perform well during the rolling phases between high-risk areas, but are less effective during the decoying phases themselves. Conversely, earthmoving wheel sets perform better during the decoying phases, but are less effective during the rolling phases. The prior art suffers from the need to compromise between decoy performance, wheel set durability, and convoy mobility.

[0009] Suspensions are provided and dimensioned to make this compromise more acceptable. Patent application EP2672218 describes a mass decoy system which includes cylinders improving the consistency of ground support, even in the case of uneven ground. US 2013 / 327203 A1 and US 2011 / 048217 A1 describe mass decoy systems which include a chassis provided with at least one running gear adapted to exert pressure on the ground, the running gear including a suspension comprising at least two compressed gas spring elements, a device for equalizing the pressures of these spring elements and at least two wheels. US 2020 / 114687 A1 describes wheels which include a hub mounted on the chassis according to a pivot connection, an elastically deformable rim, elastically deformable spokes connecting the hub to the rim and a tread fixed on the periphery of the rim. STATEMENT OF THE INVENTION

[0010] The invention aims to improve the mass decoying means of the prior art.

[0011] To this end, the invention relates to a mass decoy system intended for the protection of a following vehicle, this mass decoy system comprising a chassis provided with at least one running gear adapted to exert pressure on the ground so as to define a safe path. In this mass decoy system: the running gear comprises a suspension comprising at least two compressed gas spring elements and a device for equalizing the pressures of these spring elements; and the running gear comprises at least two wheels which comprise: a hub mounted on the chassis by a pivot connection; an elastically deformable rim; elastically deformable spokes connecting the hub to the rim; a tread fixed on the periphery of the rim.

[0012] According to another object, the invention relates to a convoy comprising a follower vehicle to be protected, and a mass decoy system as described above, connected to the follower vehicle.

[0013] The mass decoy system according to the invention has significant resistance to various attacks (projectiles, sharp stones) likely to affect the running gear. Accidents related to punctures, loose tires, etc. are simply not possible.

[0014] Furthermore, the mass decoy system according to the invention has a ground contact area which is constant, unlike the wheels of the prior art of the automobile type, which suffer from a significant increase in their ground contact area when the load increases, which reduces the pressure actually exerted on the ground and therefore reduces the capacity to trigger explosive devices.

[0015] The mass decoy system according to the invention also has improved dynamic behavior during the decoy phases, thanks to the joint elastic behavior of the suspension, the rim, and the elastically deformable spokes, unlike civil engineering type wheels whose hardness and tendency to rebound are detrimental to the consistency of support on the ground.

[0016] During the rolling phases (when the vehicle protected by the mass decoy system moves at high speed on the road, between the risk zones), the wheels of the mass decoy system have excellent longevity, the tread being protected from damage by the elastic behavior of the rim and the elastically deformable spokes.

[0017] The design of the wheels of the mass decoy system according to the invention allows a wide choice in the diameter of the wheels, without harming the inertia of the running gear. Large diameter wheels can thus be provided for mass decoy systems intended for crossing sandy areas, for example. The increase in the diameter of the wheels is achieved with a small increase in mass given the connection architecture between the hub and the rim by large elastically deformable spokes. The tread can also include imprints or projecting elements, further facilitating crossing, without harming the decoy performance thanks to this wheel architecture. The connection architecture between the hub and the rim also makes it possible to follow a transverse slope of the ground and to maintain equal ground pressure, which is not possible with rigid wheels such as civil engineering rollers.

[0018] Such a mass decoy system benefits from a suspension architecture which works in synergy with the elastic behaviour of the wheels to provide a gain both during the decoy phases and during the rolling phases.

[0019] The elastic function of the suspension is provided jointly by the elastic behavior of the rim, by the elastically deformable spokes, and by the pressure-equalizing spring elements. The elastic function of the spring elements can be provided by simple means which, in comparison with the prior art, do away with the numerous seals between cylinder rods and cylinder bodies, and the seals between cylinder pistons and cylinder bodies. The pressure is further averaged between the spring elements without requiring complex sealing means.

[0020] The spring elements only slightly limit the diameter of the fluid connection orifices, and therefore of the junction conduits between the spring elements. A limited diameter (as is the case with cylinders) in fact leads to significant pressure losses and a significant delay for the chambers of the prior art cylinders to equalize their pressure during the upward or downward movement of one or more wheels, which is detrimental to the permanence of constant support.

[0021] The mass decoy system according to the invention thus benefits from good consistency in the support of the wheels on the ground, thanks to a high gas flow rate that can vary rapidly thanks to greatly minimized pressure losses, with large volumes of gas used so as to smooth out pressure fluctuations. Reactive equalization of pressures between the wheels is also obtained, thanks to robust means that require only a few sealed joints and that do not require mobile connectors or flexible pipes.

[0022] The mass decoying system according to the invention may include the following additional features, alone or in combination: the tread is made up of layers of solid material; the tread has sculptures; the rim is made from a cylinder of elastically deformable material; the spokes have a wavy profile in their path between the rim and the hub; the hub has reinforcing ribs; the hub, the spokes and the rim are made from a single molded part; the running gear comprises a body and a suspension arm articulated on the body for each wheel, the hub of the wheel being mounted according to a pivot connection on the suspension arm, and the spring elements each comprise an air cushion connecting the suspension arm and the body; the air cushion comprises a deformable enclosure filled with a pressurized gas; the air cushion comprises at least one constriction zone;the air cushion extends in a longitudinal direction between the suspension arm and the body, and the air cushion comprises a pressure equalization orifice opening in this longitudinal direction; the system comprises a plurality of air cushions each relating to a wheel, and these air cushions are fluidically connected to each other via a reservoir; the reservoir consists of a chamber internal to the body; the reservoir consists of a pipe mounted on the body. PRESENTATION OF FIGURES

[0023] Other characteristics and advantages of the invention will emerge from the non-limiting description which follows, with reference to the appended drawings in which: there figure 1 schematically illustrates a convoy comprising a mass decoy system according to the invention, seen from above; the figure 2 is a side view of a running gear of the mass decoy device of the figure 1 ; there figure 3 illustrates a wheel of the mass decoy device; the figure 4 represents in front view the running gear of the figure 2 ; there figure 5 illustrates a variant of the running gear of the figure 4 .

[0024] Elements similar and common to the various embodiments bear the same reference numbers in the figures. DETAILED DESCRIPTION

[0025] There figure 1 illustrates an example of the general structure of a convoy 1 with mass decoy.

[0026] This convoy 1 consists of a follower vehicle 2 comprising four wheels 3, the two front wheels of which are steered, in the present example. This follower vehicle 2 is intended to be protected from dangers hidden on the ground, within the framework of the application of the invention. For this purpose, the convoy 1 comprises a mass decoy system 4 coupled to the front of the follower vehicle 2.

[0027] The mass decoy system 4 comprises rolling means for exerting pressure on the ground in front of the follower vehicle 2 so as to trigger any explosive devices encountered, thus protecting the follower vehicle 2 from the explosion. The distance between the rolling means exerting pressure on the ground and the front of the follower vehicle 2 must therefore be large enough so that the follower vehicle 2 is sufficiently far away at the time of the explosion.

[0028] The mass decoying system 4 comprises a central beam 7 to which two running gears 5 are attached, each equipped with two wheels 6. The running gears 5 are articulated on the central beam 7 by a joint 8, allowing at least one yaw pivoting of the wheels 6 or of the running gears 5. The ball joint 8 can optionally allow pivoting of the running gear 5 relative to an axis parallel to the direction of movement of the convoy 1, to allow the running gear to follow, for example, a slope on the road while the central beam is kept horizontal.

[0029] Alternatively, any other known architecture may be provided for the mass decoy system 4 (for example, fixed running gear and a central beam that can be steered, relative to the following vehicle, using jacks).

[0030] The central beam 7 can be connected to the following vehicle 2 by an articulation 9, allowing pivoting of the central beam 7 in yaw, roll and pitch.

[0031] The wheels 6 have sufficient weight so that their pressure on the ground is compatible with the desired function of triggering an explosive device, and are mounted on suspensions with an elastic element with compressed gas, including pressure equalizers.

[0032] The mass decoy system 4 defines a safe lane 10 in which the wheels 3 of the following vehicle 2 can roll safely.

[0033] There figure 2 illustrates one of the running gears 5, seen from the side.

[0034] Each of the 6 wheels (on the profile view of the figure 2 , only one wheel 6 is visible) is attached to the running gear 5 by a suspension comprising a gas spring element whose pressure is equalized with the spring elements of the other wheels.

[0035] Each running gear 5 comprises a body 22. For each wheel 6 of the running gear 5, a suspension arm 11 is connected by a pivot link 12 to the body 22. The suspension arm 11 is movable relative to the rest of the chassis with a substantially vertical movement.

[0036] The spring element of the suspension here comprises an air cushion 13 which is interposed between the body 22 and the suspension arm 11. Any other complementary element can be associated with the air cushion 13 to complete its spring function or to add a damping function to the suspension.

[0037] Each of the wheels 6 is constituted at its periphery by a rim 14 connected by elastically deformable spokes 15 to a hub 16 which is rotatably mounted on the suspension arm 11. Any known means making it possible to create a pivot connection between the hub 16 and the suspension arm 11 can be used, for example a wheel bearing.

[0038] The wheel 6 further comprises a tread 17 fixed to the periphery of the rim 14.

[0039] The rim 14 and the spokes 15 are made of an elastically deformable material. The tread 17 is sufficiently flexible to follow the deformations of the rim 14 given its elastic nature.

[0040] The expression "elastically deformable" designates in the present application elastic deformation properties which go beyond the low range of elastic deformation that all materials, including metals, can undergo. Metals are notably excluded for constituting the rim 14 and the spokes 15 because a much higher range of elastic deformation is required here. In the present example, these elements are made of a highly deformable polymer or an elastic composite material.

[0041] The hub 16, the spokes 15 and the rim 14 can also be made in a single piece by molding a polymer having good elastic properties.

[0042] The mass decoy system thus comprises a chassis (here comprising the central beam 7, the running gear 5, the suspension arms 11, etc.) on which the wheels 6 are mounted by a pivot connection 20.

[0043] There figure 3 is a detailed view of a wheel 6. In this example, the hub 16 has sufficient thickness as well as reinforcing ribs 18 guaranteeing it a certain rigidity, because the hub 16 is not intended to provide elastic behavior. The hub 18 is here fixed by screws 19 on the pivot connection 20 which is here constituted by a wheel bearing connected to the suspension arm 11.

[0044] The spokes 15 have in this example a wavy profile in their path between the rim 14 and the hub 16, promoting their flexing, to follow the strong elastic deformations permitted to the rim 14. The tread 17, which is made of flexible materials suitable for contact with the ground and sufficiently durable, is sufficiently flexible to also follow the possible deformation of the rim 14, which is produced by a cylinder of elastically deformable material.

[0045] The tread 17 here consists of a strip of solid material (i.e. without an internal chamber) and here comprises sculptures 21 allowing grip on soft ground, as for conventional tires. Alternatively, the tread 17 may be a solid and smooth strip or may comprise several layers with different properties (in the same way as the tread of a conventional tire). In any case, the tread is not intended to contain pressurized air, this role being left to the pneumatic cushion 13.

[0046] The set of elasticities of the spokes 15, the rim 14, and the tread 17 is preferably sized to give the wheel stiffness and damping characteristics comparable to a tire intended for the same use.

[0047] The wheel 6 is thus in contact with the ground with an authorized radial deformation, so as to allow the profile of the tread 17 to remain in contact with the ground at all points.

[0048] There figure 4 illustrates one of the running gears 5, seen from the front. In this example with two wheels 6 per running gear 5, the two suspension arms 11, each corresponding to a wheel 6, are mounted on the body 22 of the running gear 5.

[0049] The air bags 13 are made of a flexible material capable of containing a compressed gas. The air bag 13 is formed of a deformable enclosure filled with a pressurized gas.

[0050] The air bags 13 here have a bellows shape thanks to constriction zones 23 (only one constriction zone 23 per air bag 13 is provided in this example). Each air bag 13 thus allows the suspension arm 11 to move. When the air bag 13 is compressed, the gas contained therein (for example air) is compressed and constitutes a spring.

[0051] The body 22 of the running gear 5 is hollow here and defines an internal reservoir 24 which is therefore made up of a chamber internal to the body 22. The pneumatic cushions 13 are mechanically connected to the body 22 and are also fluidically connected to the internal reservoir 24.

[0052] The fluidically sealed connection between each air cushion 13 and the internal reservoir 24 requires only a simple connector 25 (which is fixed and not sliding or rotating), guaranteeing an airtight seal between an upper orifice 26 and a conduit 27 leading to the internal reservoir 24.

[0053] The internal reservoir 24 is located within the body 22 of the running gear 5 and can therefore be provided with a large capacity without impacting the moving elements of the suspension. The sizing of the internal reservoir 24 must however be provided to obtain an average vertical stiffness of all the wheels 6 which is acceptable. The system thus comprises a plurality of pneumatic cushions 13 each relating to a wheel 6, and these pneumatic cushions 13 are fluidically connected to each other via the reservoir 24.

[0054] The duct 27 and the orifice 26 are not very limited in diameter given the shape of the pneumatic cushion 13, preferably chosen with a large diameter, and the ducts 27 and orifices 26 can thus be sized generously to avoid pressure losses. These elements contribute to good responsiveness in the distribution of pressures. For this, the pneumatic cushion 13 extends in a longitudinal direction (the vertical direction on the figures 4 et 5 ) between the suspension arm 11 and the body 22, and the orifice 26 opens in this longitudinal direction.

[0055] The pneumatic cushion 13 carries the vertical force and ensures the suspension stiffness, without requiring an end articulation as is the case for a cylinder.

[0056] The air bags 13 are preferably made of a robust material that is not very vulnerable to leaks; they do not include any parts subject to relative friction. They can also be advantageously protected by the embodiment of the mechanical part of the suspension arm 11 and the body 22.

[0057] There figure 5 illustrates a variant embodiment of the running gear of the figure 4 . According to this variant, the function of the internal reservoir 24 is replaced by a pipe 28 mounted on the body 22, and which is therefore not an integral part of the body 22.

[0058] The pipe 28 (illustrated in this schematic view by a single pipe) can be rigid and screwed or welded to the extent that this pipe 28 is fixed relative to the body 22, without relative movement. This assembly remains simple and well protected, and allows significant exchange flow rates by providing large sections of pipe.

[0059] Alternative embodiments of the mass decoy system according to the invention can be implemented. For example, the movement between the wheels 6 and the chassis can be provided by other known elements, for example by deformable parallelogram systems or other articulations, while comprising a spring element consisting of a pneumatic cushion.

Claims

1. Mass decoy system (4) intended for the protection of a follower vehicle (2), this mass decoy system (4) comprising a chassis provided with at least one running gear (5) adapted to exert pressure on the ground so as to define a secure path (10), the one or each running gear (5) comprises a suspension comprising at least two compressed gas spring elements and a device for equalizing the pressures of these spring elements; this mass decoy system (4) being characterized in that the one or each running gear (5) comprises at least two wheels (6) which comprise: - a hub (16) mounted on the chassis according to a pivot connection (20); - an elastically deformable rim (14) ; - elastically deformable spokes (15) connecting the hub (16) to the rim (14) ; - a tread (17) fixed on the periphery of the rim (14).

2. Mass decoy system according to claim 1, characterized in that the tread (17) is made of layers of solid material.

3. Mass decoy system according to one of the preceding claims, characterized in that the tread (17) comprises sculptures (21).

4. Mass decoy system according to one of the preceding claims, characterized in that the rim (14) is made of a cylinder of elastically deformable material.

5. Mass decoy system according to one of the preceding claims, characterized in that the spokes (15) have a wavy profile in their path between the rim (14) and the hub (16)6. Mass decoy system according to one of the preceding claims, characterized in that the hub (16) comprises reinforcing ribs (18).

7. Mass decoy system according to one of the preceding claims, characterized in that the hub (16), the spokes (15) and the rim (14) are made from a single molded part.

8. Mass decoy system according to one of the preceding claims, characterized in that: the running gear (5) comprises a body (22) and a suspension arm (11) articulated on the body (22) for each wheel (6), the hub (16) of the wheel (6) being mounted according to a pivot connection (20) on the suspension arm (11); and in that the spring elements each comprise a pneumatic cushion (13) connecting the suspension arm (11) and the body (22).

9. Mass decoying system according to claim 8, characterized in that the pneumatic cushion (13) comprises a deformable enclosure filled with a pressurized gas.

10. Mass decoy system according to one of claims 8 or 9, characterized in that the pneumatic cushion (13) comprises at least one constriction zone (23).

11. Mass decoy system according to one of claims 8 to 10, characterized in that the pneumatic cushion (13) extends in a longitudinal direction between the suspension arm (11) and the body (22), and in that the pneumatic cushion (13) comprises a pressure equalization orifice (26) opening in this longitudinal direction.

12. Mass decoying system according to one of claims 8 to 11, characterized in that it comprises a plurality of pneumatic cushions (13) each relating to a wheel (6), and in that these pneumatic cushions (13) are fluidically connected to each other via a reservoir (24).

13. Mass decoying system according to claim 12, characterized in that the reservoir (24) consists of a chamber internal to the body (22).

14. Mass decoying system according to claim 12, characterized in that the reservoir (24) is constituted by a piping (28) mounted on the body (22)15. Convoy (1) comprising a follower vehicle (2) to be protected, characterized in that it comprises a mass decoy system (4) according to one of claims 1 to 14, connected to the follower vehicle (2).