FR3148220A1 - Load parachute extender and load release system comprising such an extender - Google Patents

Abstract

This extension (20) for a cargo parachute (22) comprises a strap (24), a first connecting member (26) of the strap (24) to the cargo parachute, a second connecting member (28) of the strap (24) to a load (4), an elastic member (30) intended to tighten when the strap (24) is tensioned, the elastic member (30) comprising polyurethane with a hardness of between 70 and 90 Shore A. Figure for the abstract: Fig 3

Description

Load parachute extender and load release system comprising such an extender

The technical field of the invention is the delivery by air of loads dropped from an aircraft.

In particular, the present invention relates to a cargo parachute extender, a slowdown assembly and a release system comprising such an extender.

Generally speaking, the invention fits into the existing and future air delivery environment.

Previous techniques

Dropping a load, weighing several tons, is usually done by attaching a payload to a platform slung with one or more parachutes, then dropping the platform in flight from an aircraft. The platform equipped with the payload first performs a free fall before ending up suspended under the parachutes after they have deployed.

The load includes the platform, the payload secured to it, slings connecting the platform to a canopy releaser itself connected to load parachute extensions.

The cargo parachutes are folded into a deployment bag and each include a canopy with risers connected to the extension by a connecting twin. The extension, also folded into the deployment bag, is connected to the canopy releaser.

Finally, an extractor parachute, small in size compared to the load parachute and folded into an extractor parachute bag, is attached to the load and connected to the deployment bag by an extraction strap.

During the fall of the load, the extractor parachute will make a fixed point and will extract from the deployment bag the load parachute extensions then the sails, the sails then deploying at a distance from the platform.

The tensioning of the parachute extensions is particularly violent when the canopy deploys. This phenomenon is called opening shock. The platform launched at full speed is suddenly decelerated and the payload undergoing this shock then risks being torn off the platform or damaging elements of the load.

The platform's falling speed then decreases until it reaches a stabilized descent speed under sails.

The platform then continues its descent until it hits the ground at the stabilized speed, and then experiences a new shock, called a touchdown shock, which it also transmits to the payload, risking damaging it.

The present invention therefore aims to overcome all or part of the aforementioned drawbacks, to attenuate the deceleration of a heavy load in free fall during the deployment of the load parachutes and to attenuate the shock of the load on landing.

The present invention relates to an extension for a cargo parachute, the extension comprising a strap, a first member for connecting the strap to the cargo parachute, a second member for connecting the strap to a load, an elastic member intended to tighten when the strap is tensioned, the elastic member comprising polyurethane with a hardness of between 70 and 90 Shore A.

The strap is made of, for example, polyester.

The first connecting member directly connects the strap to the cargo parachute.

The second connecting member directly connects the strap to the load. Alternatively, the second connecting member connects the strap to the load by interposing an intermediate element, for example by interposing a sail releaser.

This polyurethane with a hardness between 70 and 90 Shore A is a material of high hardness but sufficiently elastic to add a damping effect to the extension. This polyurethane makes it possible to reduce the shock when opening a slowdown assembly comprising at least one load parachute connected to at least one extension described above.

This polyurethane also helps to reduce the shock when landing a load equipped with the slowdown assembly fitted with the extension by maintaining tension in the sling just after landing.

Preferably, the polyurethane used has sufficient elongation capacity before breaking so as not to break during the impact on opening, good mechanical strength allowing the elastic member to be reused and resistance to ultraviolet radiation facilitating the storage of the extension for the slowdown assembly.

Each cargo parachute consists of a sail, the set of sails of the cargo parachutes constituting the sail.

The extension of the deceleration assembly has a shock attenuation effect when the wing opens and a shock attenuation effect when landing. The extension of the deceleration assembly thus makes it possible to drop fragile equipment and/or a larger quantity of equipment than is possible using a strap known from the prior art.

The damping effect of the slowdown assembly extension allows rapid opening of the canopy, facilitating the packaging of the canopy, in particular by removing certain elements binding the canopy to slow down its deployment. The use of the slowdown assembly extension allows a low-altitude release, in particular by allowing rapid opening of the canopy.

The invention is also applicable with any type of elastomer, the choice of elastomer modifying the longevity of the extension for the slowing down assembly. Alternatively, it is possible to use a less elastic, lighter and more robust material for the elastic member.

In a particular embodiment, the elastic member comprises polyurethane with a hardness of between 75 and 85 Shore A.

Advantageously, the extension comprises a plurality of holding members sewn to the strap, the elastic member being connected between two holding members.

Optionally, each holding member is configured such that the elastic member is capable of sliding relative to the holding member.

Optionally, each holding member is configured to secure the elastic member.

The elastic member may comprise a plurality of elastic segments. Each elastic segment may be attached to two successive holding members in the longitudinal direction of the strap.

Advantageously, the elastic member comprises at least two elastic segments, for example at least five elastic segments. Thus, in the event of rupture of a portion of the elastic segments, the remaining elastic segments make it possible to maintain a shock-absorbing function of the extension.

Preferably, the elastic member comprises nine elastic segments. If an elastic segment breaks in the event of wear of the elastic member, the remaining eight elastic segments provide eight-ninths of the damping function, the impact on the quality of the damping then being minor.

In the event of failure of the entire elastic member, in particular of all the elastic segments, the extension would regain a holding function corresponding to the strap used.

Preferably, maintenance and/or inspection measures of the extension are carried out frequently in order to eliminate worn elements.

Advantageously, the extension comprises two holding members per elastic segment, the holding members being arranged so that two longitudinally successive elastic segments are arranged on either side of the strap in the transverse direction of the taut strap.

Advantageously, the resting length of each elastic segment fixed to two holding members is two to four times less than the length of the part of the strap between said two holding members.

Optionally, the strap is braided, the elastic member being arranged inside the braids of the strap.

The maximum elongation length before rupture of the elastic member can be between 5.5 times and 7.5 times the length of the elastic member at rest.

The present invention also relates to a system for releasing a load comprising a platform for a load, the system comprising a slowing assembly comprising at least one load parachute and at least one extension as defined above connecting the load to the load parachute, the first connecting member connecting the strap to the load parachute, the second connecting member connecting the strap to the load in particular by means of a canopy releaser.

Optionally, the slowdown assembly includes at least one deployment bag comprising the load parachute and the extension.

Optionally, the release system includes an extractor parachute configured to deploy the deceleration assembly and/or a canopy releaser for detaching at least one load parachute from the load after releasing the extender.

The present invention also relates to a deployment bag comprising a load parachute and at least one extension as defined above, the first connecting member connecting the strap to the load parachute.

The present invention also relates to a slowdown assembly comprising at least one deployment bag as defined above.

Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely as a non-limiting example and made with reference to the appended drawings in which:

schematically illustrates a system for releasing a load according to the invention;

illustrates an extension according to a first exemplary embodiment of the invention stored in a deployment bag;

schematically illustrates the extension of the deployed;

schematically illustrates a traction curve of a polyurethane with a hardness between 70 and 90 Shore A;

schematically illustrates the evolution of the acceleration over time of the aircraft-dropped release system;

schematically illustrates the evolution of the speed over time of the aircraft-dropped release system;

illustrates an extension according to a second exemplary embodiment of the invention stored in a deployment bag;

schematically illustrates the extension of the deployed; and

illustrates an extension according to a third exemplary embodiment of the invention stored in a deployment bag.

Detailed description

There schematically represents a system 2 for releasing a load 4 comprising a load 4 and a slowing assembly 6. The release system 2 is capable of being released from an aircraft.

Load 4 comprises a platform 8 and a load 10 secured to platform 8, in particular a load 10 of several tonnes.

Optionally, the burden 4 comprises a damping device 12 disposed between the platform 8 and the load 10 to dampen a relative movement of the load 10 and the platform 8 tending to bring the load 10 closer to the platform 8. The damping device 12 comprises, for example, a damping material placed between the platform 8 and the load 10.

The release system 2 also comprises a sail releaser 14. The load 4 comprises a plurality of slings 16 connecting the sail releaser 14 to the platform 8 and/or to the load 10 secured to the platform 8. The slings 16 comprise, for example, straps comprising polyurethane.

The slowing assembly 6 comprises a plurality of bags 18 (one of which is shown below in ) deployment each comprising an extension 20 and a load parachute 22.

Each extension 20 includes a strap 24 (shown below in ) in particular flat, a first connecting member 26, a second connecting member 28, and an elastic member 30 (shown below in ).

Preferably, the system 2 for releasing the load 4 comprises an extractor parachute (not shown) capable of deploying the load parachutes 22 from the deployment bags 18. The extractor parachute is fixed to the load 4. The extractor parachute is intended to be connected to the aircraft by an automatic opening strap. When the system 2 for releasing is released from the aircraft, the extractor parachute deploys so as to form a fixed point in the air above the load 4 and to extract the extensions 20 and the load parachutes 22 from the deployment bags 18.

The first connecting member 26 connects the strap 24 to the cargo parachute 22. For example, the strap 24 forms a loop for attaching the first connecting member 26. The first connecting member 26 comprises, for example, a ring and/or a hook and/or a carabiner for attaching the strap 24 to the cargo parachute 22.

The second connecting member 28 connects the strap 24 to the load 4, in particular by connecting the strap 24 to the sail releaser 14 to which the slings 16 of the load 4 are connected. For example, the strap 24 forms a loop for attaching the second connecting member 28. The second connecting member 28 comprises, for example, a ring and/or a hook and/or a carabiner for attaching the strap 24 to the load 4 and/or to the sail releaser 14.

The extensions 20 in particular allow the load parachutes 22 to have sufficient space to deploy at a distance from the load 4.

The canopy releaser 14 makes it possible to separate the load parachutes 22 and the extensions 20 from the load 4 after the extensions 20 have been released. The canopy releaser 14 makes it possible to separate the load parachutes 22 and the extensions 20 from the load 4 so as to prevent the load parachutes 22 from dragging the load 4 on the ground, particularly in windy conditions.

Alternatively, the system 2 for releasing the load 4 does not include the sail releaser 14, the extensions 20 being connected, for example, to the slings 16 with shackles.

Each strap 24 connected to a load parachute 22 is, for example, adapted to support a load 10 of 1500 kilograms. The slowing assembly 6 shown comprises a number of extensions 20 and load parachutes 22 adapted to the mass of the load 4.

The slowdown assembly 6 may comprise several extensions 20 per load parachute 22.

In the example shown, the deceleration assembly 6 comprises a plurality of deployment bags 18 each comprising an extension 20 and a load parachute 22. Alternatively, the deceleration assembly 6 may comprise a deployment bag 18 comprising an extension 20 and a load parachute 22.

There schematically represents a first example of embodiment of an extension 20 stored in a bag 18 for deploying the slowdown assembly 6.

The strap 24 is folded back on itself to adapt to the length of the deployment bag 18, the deployment bag 18 being for example one meter long.

The elastic member 30 of the extension 20 is intended to tighten when the strap 24 is tensioned. For example, when the load parachutes 22 of the slowdown assembly 6 are deployed, the strap 24 unfolds and the elastic member 30 gradually tightens, the stiffness of the elastic member 30 generating an elastic return force slowing down the deployment and tensioning of the strap 24.

Optionally, the slowing down assembly 6 comprises a plurality of strangulation halyards of the load parachutes 22 (not shown) adapted to increase the deployment time of the load parachutes 22, in particular a plurality of halyards breaking one by one during the deployment of the strap 24 in order to slow down the deployment of the load parachutes 22.

Advantageously, the strap 24 has a maximum elongation length before breaking less than the maximum elongation length before breaking of the elastic member 30. Thus, the elastic member 30 does not break during deployment of the slowing assembly 6 and is reusable.

The extension 20 comprises a plurality of holding members 32 sewn to the strap 24 and connected to the elastic member 30. Each holding member 32 comprises, for example, a piece of textile sewn to the strap 24 forming a loop as well as a connecting piece adapted for fixing the elastic member 30. The adapted connecting piece comprises, for example, a Dyneema® type material making it possible to lighten the extension 20 compared to the use of metal elements.

The elastic member 30 here comprises a plurality of successive elastic segments 34, each elastic segment 34 being fixed to two successive holding members 32 in the longitudinal direction of the strap 24.

The extension 20 shown comprises two holding members 32 per elastic segment 34.

Some holding members 32, in particular intermediate holding members 32 arranged longitudinally between end holding members 32 of the elastic member 30, are sewn at the same longitudinal positions of the strap 24 so as to form pairs of holding members 32 arranged transversely on either side of the strap 24 and longitudinally at the same position of the strap 24.

This particular configuration makes it easier to store the extension 20 in the deployment bag 18 as well as to deploy the extension 20.

Preferably, the holding members 32 and the elastic member 30 are less wide than the strap 24 in order to simplify the storage of the extension 20 in the deployment bag 18 of the slowdown assembly 6 as well as the deployment of the extension 20, the strap 24 measuring for example 4.5 centimeters wide.

There schematically represents the extension 20 of the deployed and tense.

The successive elastic segments 34, running longitudinally along the strap 24, are transversely alternated on either side of the taut strap 24. Thus, when the extension 20 is deployed, the risk of interference and/or a knot forming is reduced. Thus, the risk of damaging the extension 20 is reduced and installation in the deployment bag 18 is improved.

Preferably, the resting length of each elastic segment 34 fixed to two holding members 32 is two to four times less than the length of the part of the strap 24 taken between said two holding members 32. Thus, each elastic segment 34 lengthens by one to three times its resting length when the extension 20 is tensioned.

Alternatively, the extension 20 comprises a number of holding members 32 different from twice the number of elastic segments 34.

Alternatively, the extension 20 comprises a single elastic segment 34 fixed to the holding members 32.

The elastic member 30 comprises polyurethane with a hardness of between 70 and 90 Shore A. For example, each elastic segment 34 is composed of an elastic band or several parallel elastic bands.

Preferably, the polyurethane is resistant to light and air in order to facilitate the storage of the extension 20 and the service life of the elastic segments 34.

Advantageously, the maximum elongation length before rupture of the elastic member 30 is between 5.5 times and 7.5 times the length of the elastic member 30 at rest.

An example of polyurethane suitable for producing the elastic member 30 is Courbis Courbahpure 80R ® Polyurethane.

Courbahpure 80R ® is a material with a hardness of 80 Shore A, notably with a tolerance of plus or minus three Shore A.

The elongation value at break of Courbahpure 80R ® is 550%, particularly with a tolerance of twenty percent.

There represents the tensile curve of Courbahpure 80R ®, the curve corresponding to a stress in megapascals as a function of a percentage of elongation of Courbahpure 80R ®.

The curve of the allows in particular to select an effective section of the elastic member 30 formed from Courbahpure 80R ® adapted to the number of extensions 20 of the release system 2 and to the mass of the load 4, in particular in order to form an elastic band of circular section.

For example, we are looking for the constraint to be applied to the elastic member 30 in order to obtain an elongation of the elastic member 30 of 233% adapted to the needs of the release system 2.

The holding members 32 are, for example, arranged on the strap 24 so that each elastic segment 34 elongates by 233% when the strap 24 is tensioned, an elastic segment 34 of 30 centimeters at rest measuring one meter when the strap 24 is tensioned.

Thus, for an extension 20 suitable for supporting a load 10 of between 500 and 750 kilograms, an elastic member 30 of circular section with a diameter of 24 millimeters is selected.

For an extension 20 suitable for supporting a load 10 of between 750 and 1000 kilograms, an elastic member 30 with a circular section and a diameter of 28 millimeters is selected.

For an extension 20 suitable for supporting a load 10 of between 1000 and 1250 kilograms, an elastic member 30 with a circular section and a diameter of 32 millimeters is selected.

For an extension 20 suitable for supporting a load 10 of between 1250 and 1500 kilograms, an elastic member 30 with a circular section and a diameter of 36 millimeters is selected.

The effective section of the elastic member 30 comprising polyurethane with a hardness of between 70 and 90 shore A is adapted to the load 4 intended to be supported by the extension 20.

Advantageously, the elastic member 30 has a circular section and a diameter of between 24 and 36 millimeters.

There is a schematic comparison of the evolution of the acceleration as a function of time for a release system 2 comprising the extension 20 provided with the elastic member 30 and for a release system 2 provided with the extension 20 not comprising the elastic member 30.

There is a schematic comparison of the evolution of the speed as a function of time for a release system 2 comprising the extension 20 provided with the elastic member 30 and for a release system 2 provided with the extension 20 not comprising the elastic member 30.

The release system 2 comprising the elastic member 30 is shown in dotted lines. The release system 2 not comprising the elastic member 30 is shown in solid lines.

During a free fall phase P1, the acceleration is constant and identical for the release system 2 comprising the elastic member 30 and for the release system 2 not comprising the elastic member 30.

During the free fall phase P1, the speed increases in the same way for the release system 2 comprising the elastic member 30 and for the release system 2 not comprising the elastic member 30.

During a phase P2 of deployment of the slowdown assembly 6, the load parachutes 22 are deployed. The elastic member 30 then makes it possible to reduce in absolute value the acceleration of the release system 2, limiting the shock undergone by the load 4 during the deployment of the slowdown assembly 6. The elastic member 30 also makes it possible to soften the loss of speed of the release system 2 during the deployment of the slowdown assembly 6.

During a P3 descent phase under sail, the acceleration is zero for the release system 2 comprising the elastic member 30 and for the release system 2 not comprising the elastic member 30.

During the P3 descent phase under sail, the speed is constant and identical for the release system 2 comprising the elastic member 30 and for the release system 2 not comprising the elastic member 30, the constant speed being for example 7 meters per second.

During a P4 phase of landing of the load 10, the platform 8 of the release system 2 touches the ground. The elastic member 30 then makes it possible to reduce in absolute value the acceleration of the release system 2, limiting the shock suffered by the load 4 on landing. The elastic member 30 also makes it possible to soften the loss of speed of the release system 2 during the P4 phase of landing of the load 10. Indeed, when the platform 8 touches the ground, the elastic member 30 then stretched retracts progressively in order to return to its rest position and exerts a vertical force upwards on the platform 8.

The elastic member 30 has a damping effect during the phase P2 of deployment of the slowing down assembly 6 and during the phase P4 of placing the load 10.

There schematically represents a second example of embodiment of the extension 20.

The extension 20 differs from the first exemplary embodiment in that it comprises a single elastic member 30, i.e. a non-segmented elastic member 30, and a plurality of holding members 32 configured such that the single elastic member 30 is capable of sliding through each holding member 32. The holding members 32 comprise, for example, sheaths guiding the single elastic member 30 without longitudinally constraining the single elastic member 30.

The single elastic member 30 forms, for example, a loop or a knot at each of its ends, the first connecting member 26 also being adapted to connect the single elastic member 30 to the cargo parachute 22. The second connecting member 28 is also adapted to connect the single elastic member 30 to the canopy releaser 14 or to the burden 4.

There schematically represents the extension 20 of the deployed and tensioned, the single elastic member 30 extending parallel to the tensioned strap 24.

There schematically represents a third exemplary embodiment of the extension 20. The extension 20 differs from the first exemplary embodiment in that it comprises a braided strap 24, in particular a braided strap of the Dyneema® type or a braided strap 24 called high modulus polyethylene. Such a braided strap 24 is a strap 24 with a hollow core making it possible to arrange the elastic member 30 inside the braids of the strap 24, in particular in order to reduce the bulk of the extension 20.

The third exemplary embodiment may include a plurality of holding members 32 configured to secure the elastic member 30 and/or a plurality of holding members 32 configured such that the elastic member 30 slides through the holding member 32.

Claims (10)

Extension (20) of a load parachute (22), the extension (20) comprising a strap (24), a first connecting member (26) of the strap (24) to the load parachute (22), a second connecting member (28) of the strap (24) to a load (4), an elastic member (30) intended to tighten when the strap (24) is tensioned, characterized in that the elastic member (30) comprises polyurethane with a hardness of between 70 and 90 Shore A. An extender (20) according to claim 1, comprising a plurality of holding members (32) sewn to the strap (24), the elastic member (30) being connected between two holding members (32). The extension (20) of claim 2, wherein each holding member (32) is configured such that the resilient member (30) is capable of sliding relative to the holding member (32). Extension (20) according to one of claims 2 and 3, in which each holding member (32) is configured to fix the elastic member (30). Extension (20) according to any one of claims 2 to 4, in which the elastic member (30) comprises a plurality of elastic segments (34), each elastic segment (34) being fixed to two successive holding members (32) in the longitudinal direction of the strap (24). Extension (20) according to claim 5, in which the resting length of each elastic segment (34) fixed to two holding members (32) is two to four times less than the length of the portion of the strap (24) between said two holding members (32). Extension (20) according to one of claims 5 and 6, comprising two holding members (32) per elastic segment (34), the holding members (32) being arranged so that two longitudinally successive elastic segments (34) are arranged on either side of the strap (24) in the transverse direction of the stretched strap (24). An extender (20) according to any one of claims 1 to 6, wherein the strap (24) is braided, the elastic member (30) being disposed inside the braids of the strap (24). Extension (20) according to any one of claims 1 to 8, in which the maximum elongation length before rupture of the elastic member (30) is between 5.5 times and 7.5 times the length of the elastic member (30) at rest. A system (2) for releasing a load (4) comprising a platform (8) for a load (10), the system (2) comprising a slowing assembly (6) comprising at least one load parachute (22) and at least one extension (20) according to any one of claims 1 to 9 connecting the load (4) to the load parachute (22), the first connecting member (26) connecting the strap (24) to the load parachute (22), the second connecting member (28) connecting the strap (24) to the load (4) in particular by means of a sail releaser (14).