Method and device for dampening the shock felt by a payload during landing

Abstract

This device relates in particular to a damping assembly (125) for a payload (110), said assembly comprising a damping element (135) extending along a plane and configured to dampen a shock along an axis essentially perpendicular to said plane, and a lifting device (140) comprising a lifting airbag (165) provided with a filling (170), closure, and deflation element, the lifting device being configured to bear on said payload and on said drop platform, along an axis perpendicular to the plane and through said damping element. Figure 2

Description

Title of the invention: Method and device for dampening the shock felt by a payload during landing technical field

[0001] The invention relates to the protection of a payload such as wheeled or tracked vehicles or machines during their transport, but especially during their dropping, packaged in bundles, from an aircraft. Previous techniques

[0002] For many reasons, it may be necessary to drop payloads from aircraft, for example vehicles. To protect these payloads during landing, it is necessary to provide damping devices.

[0003] In particular, there are shock-absorbing systems based on honeycomb cardboard. Setting up such a system for shock-absorbing a vehicle to be dropped involves assembling stacks of honeycomb cardboard sized to meet a desired crushing rate, then arranging these stacks on the drop platform according to a precise plan described in user documentation that varies depending on the type of payload. After gluing the cardboard stacks and allowing them to dry, the payload to be dropped must be slung, lifted, the pre-equipped platform placed under the vehicle, and then the payload lowered onto the cardboard stacks before being secured to the platform. Upon impact, at landing, it is the crushing of the cardboard, by vertical buckling, that absorbs the kinetic energy and dampens the shock. Once on the ground, it is necessary to remove the securing system and then the cardboard blocks to release the vehicle.

[0004] Although this solution proves effective, it has many drawbacks. In particular, setting up such a system requires several hours of preparation and drying, and the arrangement of the cardboard stacks varies depending on the payload to be loaded, necessitating careful review of the user documentation. This solution also requires significant handling equipment such as hoists or gantries. Furthermore, it is rare for the platform to land at a perfectly perpendicular speed to the ground during a landing impact. In fact, the platform generally lands at a low horizontal speed, which often necessitates oversizing the cardboard stacks, at the risk of them not compressing sufficiently and the payload not making contact with the platform after landing, thus complicating its recovery.

[0005] Finally, vehicle recovery is often laborious and time-consuming because it is necessary in particular to extract the cardboard placed under the vehicle before it can be extracted from the platform.

[0006] Solutions also exist based on a pneumatic system attached to an airdrop platform. This system includes lifting cushions that provide the system with two positions: an uninflated position allowing a vehicle to be driven onto the platform to position its wheels on the system, and an inflated position in which the vehicle is raised at all four wheels. The lifting cushions also act as shock absorbers by deformation. Hydraulic cylinders are further used to dampen vehicle oscillations and control its movement relative to the platform. Such a system is described in particular in patent application WO 2012 / 003285.

[0007] These systems also have drawbacks. In particular, they present a risk of damage to the vehicle's suspension. Description of the invention

[0008] The object of the invention is to propose a damping system for a payload, which is effective, simple to put in place and to remove, reusable and which preserves the various elements of the payload, in particular the suspensions when the payload is a vehicle.

[0009] According to one aspect, the invention relates to a damping assembly for a payload transported on a drop platform, said assembly comprising

[0010] - a damping element extending along a plane and configured to dampen a impact along an axis essentially perpendicular to said plane and

[0011] - a lifting device, separate from the damping element, comprising a inflatable lifting cushion equipped with a filling, closing and emptying element,

[0012] the lifting device being configured to bear on said payload and on said release platform, along an axis perpendicular to the plane and through said damping element.

[0013] The damping assembly according to the invention is easy to store, handle, deploy, and remove. It protects a payload against vertical impacts and also against vertical impacts including a horizontal component. The damping assembly according to the invention allows the damping of a payload such as a vehicle during an impact, in particular an impact upon landing following a drop, for example, from an aircraft. It allows for simple and economical deployment and retrieval, for example, using a single operator and a simple Compressed air compressor (for installation). It takes up little space, does not require special handling equipment and can be reused.

[0014] According to one feature, the lifting device further comprises

[0015] - a guide element provided with a cylindrical cavity extending along an axis longitudinal perpendicular to said plane and having at least one end partially closed along a plane parallel to said plane and

[0016] - a sliding element in the cylindrical cavity along a longitudinal axis of the cylindrical cavity and extending outside the cylindrical cavity, opposite said end,

[0017] said lifting airbag being arranged in the cylindrical cavity, between said end and the sliding element, and

[0018] one of the guide element and the sliding element being configured to bear on said payload and the other of the guide element and the sliding element being configured to bear on said drop platform, along an axis perpendicular to the plane and through said damping element.

[0019] According to one feature, the lifting airbag is a pneumatic lifting airbag, particularly easy to implement, for example using a simple air compressor for inflation.

[0020] According to one feature, the assembly further includes a distributing base to distribute a force from the lifting device onto said damping element and thus provide better damping.

[0021] According to one feature, the assembly further includes an interface element between the lifting device and said payload, thus limiting the risks of damage to the payload and offering better cushioning.

[0022] According to one characteristic, said damping element is a viscoelastic damping element.

[0023] According to one feature, said guide element includes an oblong access opening to said filling element, facilitating access to said filling element regardless of the filling state of said lifting airbag.

[0024] According to another aspect, the invention relates to a method for protecting a payload, the method comprising:

[0025] - the installation of said payload on a drop platform;

[0026] - the establishment, between said payload and said platform, of at least one damping system as described above;

[0027] - the at least partial filling of said lifting airbag; and

[0028] - the securing of said payload to said platform.

[0029] The method according to the invention thus allows the damping of a payload such as a vehicle during an impact, in particular an impact upon landing following a drop, for example by aircraft. It allows for simple and economical setup of the payload, for example using a single operator and a simple compressed air compressor, without the need for special handling equipment.

[0030] According to another feature, the method includes, after filling said lifting airbag, closing a filling valve.

[0031] According to another aspect, the invention relates to a method for recovering a payload from a drop platform, said payload resting on at least one damping assembly as described above, the method comprising:

[0032] - the at least partial emptying of the lifting airbag of said at least one depreciation set;

[0033] - the removal of said at least one set of damping; and

[0034] - the extraction of said payload from said platform.

[0035] The method according to the invention allows for the cushioning of a payload such as a vehicle during an impact, particularly an impact upon landing following a drop, for example from an aircraft. It allows for simple and economical recovery of the payload, for example with the help of a single operator.

[0036] According to one feature, said emptying of said lifting airbag includes the opening of a filling valve. Brief description of the drawings

[0037] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example, and made with reference to the accompanying drawings in which:

[0038] [Fig.1] schematically represents a vehicle mounted on a drop platform for the purpose of being dropped from an aircraft, according to embodiments of the invention;

[0039] [Fig.2] illustrates a cross-sectional view of an example of a damping system, in a configuration allowing the movement of a payload to be protected, according to embodiments of the invention;

[0040] [Fig.3] illustrates a cross-sectional view of an example of a damping system, in a configuration allowing the protection of a payload in case of impact, according to embodiments of the invention;

[0041] [Fig.4] illustrates an exploded view of an example of a lifting device as illustrated in Figures 2 and 3;

[0042] [Fig. 5] illustrates an example of the steps involved in preparing a vehicle for release by an aircraft, according to embodiments of the invention; and

[0043] [Fig.6] illustrates an example of unconditioning steps of a vehicle dropped by an aircraft, according to embodiments of the invention. Detailed description of at least one embodiment

[0044] A detailed description of particular embodiments of the invention will be given below, with reference to the drawings in which the same references identify the same structural elements in each of the figures.

[0045] Fig. 1 schematically represents a vehicle mounted on a drop platform for drop from an aircraft, according to embodiments of the invention.

[0046] As illustrated, the assembly 100 here comprises a drop platform 105, also called an airdrop platform when used to drop a payload such as a vehicle from an aircraft, and a vehicle 110. The assembly 100 further comprises a structure 115, attached to the drop platform 105, on which one or more descent control and deceleration systems 120 are mounted, for example, one or more parachutes. In some embodiments, the descent control and deceleration system(s) are attached to the drop platform 105 in order to slow the descent of the drop platform 105.

[0047] The assembly 100 also includes damping assemblies 125-1 and 125-2, generically referenced as 125, as well as lashing elements 130, for example straps, for securing the payload, here the vehicle 110, to the drop platform 105.

[0048] It is observed here that the number of damping assemblies depends on the characteristics of these assemblies and the characteristics of the payload, in particular its weight and weight distribution. To ensure payload stability, at least three damping assemblies are used. For a vehicle, four damping assemblies can be used to support the front and rear, on each side. Additional damping assemblies can be used, for example, at the front or rear, depending on the overhang and weight distribution.

[0049] Examples of damping assemblies are described with reference to Figures 2, 3 and 4.

[0050] Figure 2 illustrates a cross-sectional view of an example of a damping system 125, in a configuration allowing the movement of a payload to be protected, according to embodiments of the invention. Figure 3 illustrates a similar cross-sectional view, in a configuration allowing the protection of the payload.

[0051] As illustrated, the damping system 125 is positioned between a drop platform 105 and a payload such as the vehicle 110. It includes a damping element 135 and a lifting device 140.

[0052] The damping element 135 is, for example, a foam such as a viscoelastic foam. Its purpose is to absorb the kinetic energy transmitted by the payload. According to the illustrated example, the damping element extends over the release platform 105, between the release platform 105 and the lifting device 140. In some embodiments, a distribution plate 145 is used between the damping element and the lifting device to distribute the kinetic energy transmitted by the payload over a large area of ​​the damping element. In other embodiments, the damping element is arranged between the lifting device and the payload.

[0053] By way of illustration, the damping element 135 is a viscoelastic foam made from polyurethane.

[0054] In particular embodiments, an interface element 150 is interposed between the lifting device 140 (or, where applicable, the damping element) and the payload, for example, the vehicle 110. This interface element distributes the forces transmitted by the payload onto the lifting device, the upper surface of which is, in particular embodiments, flat. Thus, the interface element may comprise a flat lower face and an upper face conforming to the shape of the payload. In particular embodiments, the interface element comprises a deformable material, such as foam, to conform to the shape of the payload at the point where it bears against it. Again, this may be polyurethane foam.

[0055] According to the example illustrated in Figures 2, 3, and 4, the lifting device comprises a guide element 155 having a cylindrical cavity extending along a longitudinal axis substantially perpendicular to the plane of the release platform 105. This cylindrical cavity is at least partially closed at one end, here in its upper part, along a plane substantially parallel to the plane of the release platform 105. The lifting device also comprises a sliding element 160, configured to slide within the cylindrical cavity of the guide element 155, along a longitudinal axis of the cylindrical cavity. The sliding element 160 extends outside the cylindrical cavity, opposite the closed end of the cylindrical cavity. Furthermore, the lifting device comprises an inflatable lifting cushion 165 disposed within the cylindrical cavity, between the closed end of the cylindrical cavity and the sliding element.As described with reference to [Fig.4], the lifting airbag includes a filling, closing and emptying element 170.

[0056] When the lifting airbag is in an empty or partially empty state, the guide element 155 is in a low position due to its mass, as illustrated in [Fig. 2], preferably without contact with the payload. The payload can then be handled freely, in particular to be installed on the drop platform or extracted from this platform.

[0057] When the lifting airbag is inflated or partially inflated, the increase in its volume moves the sliding element away from the closed end of the cylindrical cavity, driving the guide element into a raised position and lifting the payload if it is placed on the lifting device, as illustrated in [Fig. 3]. The payload is then protected, in the event of a vertical or essentially vertical impact, by the combined effect of overpressure in the lifting airbag and the damping element, which is exerted at the point of support of the lifting device (or the damping element, as applicable) on the payload. This point of support is chosen according to the characteristics of the payload. It is generally supplied by the payload manufacturer.

[0058] Figure 4 illustrates an exploded view of an example of a lifting device as shown. on figures 2 and 3.

[0059] According to this example, the guide element 155 comprises a ring or body 155-1 and an upper plate or closing piece 155-2 which is attached to the ring, for example by screwing. The ring 155-1 comprises a cylindrical cavity, which here has a square base. The upper plate corresponds here to the closed end of the cylindrical cavity referred to above.

[0060] The crown further comprises, in its lower part, an opening 155-3, preferably central, allowing passage of the sliding element 160, as well as an oblong opening 155-4, here at an angle, for accessing the filling, closing, and emptying element 170 of the lifting airbag 165, whether the guide element is in its lower or upper position. The inner sides of the crown 155-1 measure, for example, between 100 mm and 1,500 mm, for example, 200 mm. Its height is, for example, between 50 mm and 300 mm, for example, 130 mm. Other crown shapes may be used.

[0061] The crown 155-1 and the top plate 155-2 can for example be made of aluminium, for example of aluminium 6082 with a thickness between 5 and 20 mm.

[0062] According to the illustrated example, the sliding element 160 comprises two parts: a lifting airbag support including a body 160-1, a support piece 160-2, and a lower plate 160-3. The body 160-1 is formed of a cylinder whose shape and base dimensions correspond substantially to the opening 155-3 of the ring 155-1 of the guide element 155, such that the body 160-1 slides freely within the opening 155-3. The shape and dimensions of the support piece 160-2 correspond substantially to the base of the cylindrical cavity of the guide element 155, such that the support piece 160-2 slides freely in the cylindrical cavity of the guide element 155. The lower plate 160-3 is fixed to the body 160-1, for example by screwing, after mounting the sliding element 160 in the guide element 155. By way of illustration, the height of the body 160-1 can be substantially equal to the height of the crown 155-1.

[0063] Like the parts of the guide element 155, the parts of the sliding element 160 can for example be made of aluminium, for example of aluminium 6082.

[0064] The lifting airbag 165 can, for example, support a load of less than 5 tonnes, for example a load of 3 tonnes, can withstand a maximum pressure of 12 bar, can have a vertical travel capacity of less than 250 mm, for example 115 mm, can have a thickness between 5 and 30 mm, for example 20 mm, and / or can be square in shape with, for example, sides of length between 100 mm and 1,500 mm, for example 200 mm. The shape and size of the lifting airbag preferably correspond, in a horizontal plane, to those of the base of the cylinder corresponding to the cavity formed by the ring 155-1 such that the lifting airbag occupies the entire space between the upper plate 155-2 and the support piece 160-2. The inflatable lifting cushion, for example, is made from a reinforced aramid sheet coated with hot-vulcanized elastomer.

[0065] As described previously, the lifting airbag 165 includes a filling, closing, and emptying element 170. This element is positioned in a corner of the lifting airbag. It may include a valve, for example, a brass valve capable of operating at a maximum pressure of 20 bar and providing a maximum flow rate of 1.4 m³ / h. Inside the lifting airbag, this valve may be extended by a tubular section for injecting a fluid, for example, air, into the lifting airbag. Outside the lifting airbag, this valve may be extended by a connector or a valve provided with a nozzle, preferably a standard one, for connection, for example, to a compressor.

[0066] According to other embodiments, the lifting device 140 essentially consists of an inflatable lifting cushion, for example similar to the inflatable lifting cushion 165.

[0067] Figure 5 illustrates an example of the steps involved in preparing a vehicle for release by an aircraft, according to embodiments of the invention.

[0068] As illustrated, a first step (a) here aims to bring the vehicle 110 onto the drop platform 105, to the location it is to be transported to.

[0069] In a second step (b), damping assemblies are positioned under the vehicle. By way of illustration, four damping assemblies can be positioned: one at the front left, referenced 125-1; one at the rear left, referenced 125-2; one at the front right (not visible); and one at the rear right (not visible). These Damping assemblies can be similar to those described with reference to Figures 2, 3, and 4. A different number of damping assemblies can be used. This number can be determined, in particular, according to the characteristics of the assemblies, especially their lifting capacity, and those of the payload, especially its weight.

[0070] It is observed here that one or more damping assemblies according to the invention can be used in combination with known systems, for example one or more stacks of cardboard.

[0071] In a subsequent step (c), the lifting airbag of each damping assembly is inflated, for example with air and using a compressor 500. The filling, closing, and deflation element of the lifting airbag is then actuated to close it. The inflation pressure is determined according to the characteristics of the damping assemblies and the mass of the vehicle 110.

[0072] According to particular embodiments, several damping assemblies are linked together, at the level of the filling, closing and emptying elements, to allow the lifting airbags to be inflated simultaneously.

[0073] The vehicle is then secured (step (d)) to the drop platform, for example using straps 130.

[0074] Figure 6 illustrates an example of unpacking steps for a vehicle dropped by an aircraft, according to embodiments of the invention.

[0075] When the assembly, including the drop platform 105 and the vehicle 110, lands after being dropped (step (a)), the vehicle is untied, for example by removing the straps 130 (step (b)). It is noted here that the shock absorption during landing is achieved by a combination of overpressure in the lifting cushions and by the damping elements, for example made of viscoelastic foams, which allow deformation in all directions.

[0076] In a subsequent step (step (c)), the lifting airbag of each cushioning assembly is deflated, for example by actuating the filling, closing and emptying element of the lifting airbag to open it, for example by turning a fill / empty valve.

[0077] Again, according to particular embodiments, several damping assemblies are interconnected at the filling, closing, and emptying elements to allow the lifting airbags to be deflated simultaneously. For example, the filling, closing, and emptying elements may be connected to a common valve.

[0078] The damping assemblies are then removed (step (d)) and the vehicle is extracted from the drop platform (step (e)), for example from the front, while rolling.

Claims

Demands

1. Damping assembly (125) for a payload (110) carried on a drop platform, said assembly comprising - a damping element (135) extending along a plane and configured to dampen a shock along an axis substantially perpendicular to said plane and - a lifting device (140), separate from the damping element, comprising a lifting airbag (165) provided with a filling (170), closing and emptying element, the lifting device being configured to bear on said payload and on said drop platform, along an axis perpendicular to the plane and through said damping element.

2. Assembly according to claim 1, wherein said lifting device (140) further comprises - a guide element (155) having a cylindrical cavity extending along a longitudinal axis perpendicular to said plane and having an end at least partially closed along a plane parallel to said plane and - a sliding element (160) in the cylindrical cavity along a longitudinal axis of the cylindrical cavity and extending outside the cylindrical cavity, opposite said end, said lifting airbag (165) being arranged in the cylindrical cavity, between said end and the sliding element, and one of the guide element and the sliding element being configured to bear on said payload and the other of the guide element and the sliding element being configured to bear on said drop platform, along an axis perpendicular to the plane and through said damping element.

3. Assembly according to claim 1 or claim 2, wherein the lifting airbag is a pneumatic lifting airbag.

4. Assembly according to any one of claims 1 to 3, further comprising a distributing base (145) for distributing a force from the lifting device (140) onto said damping element (135).

5. Assembly according to any one of claims 1 to 4, further comprising an interface element (150) between the lifting device (140) and said payload (110).

6. Assembly according to any one of claims 1 to 5, wherein said damping element (135) is a viscoelastic damping element.

7. Assembly according to any one of claims 2 and 3 to 6, directly or indirectly dependent on claim 2, wherein said guide element (155) comprises an oblong opening (155-4) for accessing said filling element (170).

8. A method for protecting a payload (110), the method comprising: - installing said payload on a drop platform (105); - placing, between said payload and said platform, at least one damping assembly according to any one of claims 1 to 7; - at least partial filling of said lifting airbag; and - fixing said payload to said platform.

9. Method according to claim 8, comprising, after filling said lifting airbag, closing a filling valve.

10. Method of removing a payload from a drop platform, said payload resting on at least one damping assembly according to any one of claims 1 to 7, the method comprising: - at least partial emptying of the lifting airbag of said at least one damping assembly; - removal of said at least one damping assembly; and - removal of said payload from said platform.

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