Field of the invention This application relates to an aerial delivery container for release from an aircraft and, in particular, an aerial delivery container for release from an aircraft comprising an impact absorbing structure.

Background of the invention

Conventional aerial delivery systems have been developed to allow goods and personnel to be delivered to inaccessible or hard-to-reach locations. For example, emergency relief can quickly be delivered to regions which are cut off from usual delivery routes and supplies can be safely delivered to bases in hostile environments. Aerial delivery is advantageous because it allows these deliveries to be made with the minimum of risk and aerial delivery is often the fastest way of delivering goods to these areas.

Conventional aerial delivery systems generally comprise a platform, onto which the goods are secured, or a container, which is coupled to a parachute. The container or platform will then be dropped at a height from an aeroplane or helicopter above a target location, with the parachute slowing the descent of the package. The goods can subsequently be recovered at the target location.

Alternatively, due to high costs associated with the use of parachutes and difficulties in recovering parachutes, goods may be dropped without a parachute, using free drop methods. There are inevitable risks that the goods being delivered will be damaged or persons at the point of impact will be injured or killed.

These aerial delivery systems will often comprise a form of impact absorbing structure to further reduce the risk of damage to the contents of the delivery system. Examples include the use of cardboard boxes underneath a pallet to absorb some of the impact upon descent, the use of metal honeycomb structures and the use of honeycomb cardboard.

However, these prior art impact absorbing structures have relatively rigid structures extending in the direction of impact, which means that when the aerial delivery assembly initially impacts the ground, there is no instantaneous deformation of the impact absorbing structure. Instead, the impact absorbing structure remains intact until a peak force is reached, at which point the impact absorbing structure immediately deforms. Thus, once the resistance provided by the impact absorbing structure is overcome, there is very little, or no resistance, provided by the impact absorbing structure for the remainder of the impact. This sudden deformation can cause the goods contained within the hold to rapidly move within the hold (i.e. as a result in the rapid change in speed), thereby risking damage to the goods.

Furthermore, the existing assemblies are often expensive to implement and difficult to construct and therefore do not lend themselves to delivery of low cost goods by cheap parachute assemblies, nor to mass production of aerial delivery systems.

Summary of the invention According to a first aspect of the invention, there is provided an aerial delivery container for release from an aircraft, the aerial delivery container comprising a housing defining a hold for containing a payload and an impact absorbing structure provided to the housing for absorbing the force of an impact. The impact absorbing structure comprises a tubular body extending in a longitudinal direction, the tubular body being defined at least partially by a deformable longitudinal wall and wherein the wall is configured such that, in use, an impact force applied to the impact absorbing structure in the longitudinal direction causes the deformation of the tubular body. Further, the deformable side wall comprises a plurality of deformable cells distributed along the longitudinal direction such that a force applied to the impact absorbing structure in the longitudinal direction causes the progressive longitudinal deformation of the impact absorbing structure.

Embodiments therefore provide a container or enclosure that can be used to deliver a payload by aerial delivery - e.g. by release from an aircraft - the enclosure having sidewalls, an internal hollow defined by the sidewalls into which the goods can be received and a collapsible or compressible base for reducing or preventing damage to the remainder of the enclosure and the contents of the enclosure. The compressible base in this embodiment comprises a hollow tubular body having a sidewall or sidewalls provided with a plurality of or individual collapsible bodies or compartments positioned along the sidewalls in an arrangement extending away from the base of the enclosure. In this way, when the base of the container impacts the ground or a surface onto which it lands, the compressible base is crushed and each of the compartments is deformed as the base is crushed. The compartments or cells provide an additional resistance against an impact as well as serving to normalise the force by increasing the duration for which the impact absorbing structure can resist an impact, as compared to existing impact absorbing structures which do not employ cells.

The use of such a deformable tubular body in a container for aerial delivery provides a significant improvement in impact reduction. The use of the tubular body having a deformable wall comprising deformable cells distributed in the longitudinal direction provides an impact absorbing material which deforms progressively as a force is applied co-linear with the longitudinal central axis of the tubular body. In particular, an impact against the container (e.g. when the container hits the ground) causes the deformation of the walls of the tubular body, which in itself absorbs some of the impact of the force applied to the aerial delivery container, and also causes deformation of each cell in the deformable wall, which also further absorbs some of the force caused by the impact. The deformation of each cell will provide a cushioning effect and, since there a plurality of cells distributed along the longitudinal axis, this provides a series of regions along the longitudinal direction in which there is an additional impact absorbing effect. If, as in some embodiments, the sidewalls of the tubular body are all walls comprising deformable cells, then this effect is magnified. In other words, in all embodiments, the cells provide additional resistance against deformation and, due to their arrangement along the wall of the tubular body in the direction that is most likely to be impacted when the aerial delivery container is in use, the resistance provided by each cell will only be overcome once the wall has deformed sufficiently to apply to force to the cell in question. Thus, the cells will not all deform simultaneously but instead will deform one after the other. As a result, the arrangement of the cells has the effect of normalising the deformation of the impact absorbing structure and also increasing the duration for which the impact absorbing structure acts to absorb an impact. This in turn reduces the risk of damage to the remainder of the aerial delivery box and its contents by providing a smoother impact resistance, together with overall increased resistance.

By "cell" (e.g. deformable cell) it is meant a body having a single continuous side wall or multiple sidewalls enclosing or defining a hollow. In an embodiment, the body of the cell can completely enclose the hollow (a "closed" cell), or, in another embodiment, the body can have an opening (an "open" cell). In some embodiments, the plurality of cells may comprise a mixture of open and closed cells or the impact absorbing structure may comprise a plurality of tubular bodies with at least one tubular body having open cells and at least one tubular body having closed cells. Where an opening is present, in an embodiment restrictions may also be provided across the opening so as to impede the flow of air in and out of the opening, and where the cell is a closed cell, embodiments may include cells with weakened or frangible portions so as to assist in deformation of the cell or provide a more controlled deformation. The cells can be any shape, for example a regular shape, such as a sphere, a cylinder or rectangle, or can be irregular shapes.

As will be appreciated, the resistance should not be too high so as to resist any deformation on impact. Thus, the impact absorbing structure should be adapted so as to deform before the housing and hold deforms so as to prevent damage to the hold and the contents of the hold.

The use of cells, open and/or closed, also has the advantage that the air provided within the cells must be displaced as the walls of the cell and the walls of the tubular body are deformed. Particularly in the embodiments using closed cells or embodiments in which open cells are provided with a form of airflow resistance, but also to an extent for open cells at the opening which inevitably provides some resistance to airflow, the cells provide a further resistance which must be overcome by the force applied to the impact absorbing structure and thus increases the force that can be absorbed by the impact absorbing structure. This also provides a normalising effect because the air will typically not be displaced from the entire structure immediately. The shape of the cell can also be modified to reduce or increase the speed at which airflow can exit the cell, thereby modifying the resistance provided by the cell.

An additional benefit of the use of cells is that embodiments provide an arrangement in which the cells interrupt the deformation of an otherwise continuous wall. In arrangements where impact absorbing structures have a tubular body having walls without cells positioned along the direction of impact, the walls tend to deform at a single point of failure. If this single point of failure (e.g. the point at which the wall collapses) is spaced apart from the end of the impact absorbing structure nearest the hold, then the hold and its contents may travel some distance before it comes to a halt. This travel can lead to damage. Where cells are provided along the walls and are spaced apart from one another, particularly where cells are integral in the walls, this can cause the wall to act as a series of individual wall sections extending in the impact direction. This has the effect of creating a number of smaller sections that deform (i.e. the wall portions between each sequential cell) and thereby reduce the negative effects of a single point of failure in the tubular body. This also reduces the chance of unwanted deformation, such as the movement of the wall in a lateral direction, rather than deformation in a longitudinal direction, for example, which can occur in tubular bodies without cells positioned along the direction.

By tubular body it is meant a body formed of a plurality of sidewalls or a single continuous extending sidewall around a longitudinal axis and defining a hollow region within the sidewalls. The sidewall(s) thus define a pipe or cylinder/prism-like structure, optionally with flat end faces defined by the ends of the sidewalls. In some configurations, the tubular body may have an end wall or end walls at either end of the sidewalls which extend between the sidewall(s) to enclose the hollow, or alternatively the tubular body may be open at either end of the sidewalls. The tubular structure may be, but does not have to be, elongate. In particular, the length of the tubular structure in the longitudinal direction may be greater than its width in a transverse or lateral direction. The sidewall or sidewalls of the tubular structure may extend entirely around the longitudinal axis to form a continuous wall or, alternatively, there may be discontinuity in the sidewall(s). The tubular structure can be any suitable shape, such as a polyhedron, e.g. a self-supporting polygonal cell, or the tubular structure may have a cylindrical shape. For example, the tubular structure may be in the shape of a cylinder, a prism (such as a rectangular prism (cuboid), a pentagonal prism, a hexagonal prism, a heptagonal prism, an octagon prism or a triangular prism). Cross-sections taken at points along the longitudinal axis (i.e. forming a lateral or transverse plane) of the tubular body do not necessarily have to have the same shape and/or size along but, in a preferred embodiment, the cross-section shape and size of the tubular body along the longitudinal axis is same along its entire length. In some embodiments in which there are multiple tubular bodies, a tubular body may share a sidewall with an adjacent tubular body. For example, a sidewall of one tubular body may also form the sidewall of a second, adjacent tubular body. In this way, a reduced amount of material may be required and the tubular bodies serve to structurally support one another.

By container it is meant a body that is capable of holding or containing an object, such as an enclosure or a housing in which an object can be received. A container can include a box, a vessel, a canister, a case and/or a bag.

In an embodiment, the tubular body is a polyhedron; for example, a rectangular prism (cuboid), a pentagonal prism, a hexagonal prism, a heptagonal prism, a octagon prism or, preferably, a triangular prism. The use of a polyhedron shape provides improved protection for a payload contained within the container as it provides a uniform shape the benefit provided by having the superior strength of a self-supporting polygonal cell, which provides resistance to deformation and a more uniform deformation thereby further improving the linearity of the deformation and thus providing a more cushioned landing for the aerial delivery container. Furthermore, the use of polyhedrons over other shapes enables the close packing of the tubular bodies in the impact absorbing structure thereby allowing more tubular bodies per unit of area and thereby increasing the impact absorbing properties of the impact absorbing structure. Preferably, the polyhedron is a rectangular prism or, even more preferably a triangular prism. Reducing number of corners (i.e. joins between the flat longitudinal faces of the polygons) further improves the uniformity of deformation as it reduces the opportunity for failure along an edge.

In an embodiment, in a longitudinal cross section of the wall, the deformable cells are closed cells. In this embodiment, the impact absorbing structure provides additional resistance, as the air contained within each of the deformation of the cells must be displaced in the impact and, moreover, the air is displaced in a direction substantially perpendicular to the direction in which the force is applied and therefore it provides a cushioning effect without the risk of interfering with the deformation or causing the cell and/or tubular body to deform in an unintended manner (e.g. if air is trapped in the cell). This, combined with the resistance already provided by the presence of a plurality of cells distributed along the longitudinal direction provides a further improved normalisation of the deformation of the impact absorbing structure. It will be appreciated that the deformable cells in this embodiment may be closed or open in another cross-sectional plane, for example in a lateral plane perpendicular to the longitudinal plane. Thus, in an embodiment, in a transverse cross section of the cell, each cell is an open cell. In this way, when the cells are deformed and air is forced out of the cell, air will be directed in a predetermined direction - i.e. in a direction substantially perpendicular to the direction in which the force is applied and therefore it provides a cushioning effect without the risk of interfering with the deformation or causing the cell and/or tubular body deform in an unintended manner.

In one embodiment, the deformable cells are closed cells - in other words closed in all cross-sections. In some embodiments of this closed cell arrangement, parts of the sidewalls of the cell may be provided with a preformed weakness adapted to perforate when the cell is deformed by an impact. In this way, when the cells are deformed and air is forced out of the cell, the weakness will rupture and air will be directed in a predetermined direction. In one embodiment of this arrangement, the preformed weakness is provided to direct air perpendicular to the longitudinal direction (i.e. the direction of the force of the impact). For example, the preformed weakness may be a weakness resulting in an opening having a central axis perpendicular to the longitudinal direction. Alternatively, or in addition, each deformable cell may comprise an air flow restriction for restricting of airflow within the deformable cell.

In an embodiment, the deformable cells are elongate cells and each deformable cell extends at least partially across the width of the longitudinal wall (sidewall) of the tubular body in a transverse direction. In an embodiment, each deformable cell is a tubular shape having a central axis extending in the transverse direction. In this embodiment, tubular shape has the same meaning as tubular body, defined above.

In an embodiment, the deformable cells extend across the entire width of the longitudinal wall of the tubular body in the transverse direction. In this embodiment, the arrangement of the deformable cells across the sidewalls of the tubular body in a direction perpendicular to the longitudinal axis ensures that any deformation of the longitudinal wall in the same plane as a deformable cell improves the application of the force to the deformable cell. In an embodiment, the longitudinal wall extends circumferentially about the entire circumference of the tubular body; or wherein the tubular body comprises a plurality of deformable longitudinal walls, the plurality of deformable walls extending circumferentially about the entire circumference of the tubular body. This provides a stable and uniform structure.

In an embodiment, the longitudinal wall comprises a continuous backing layer extending the length of the tubular body in the longitudinal direction and wherein the deformable cells are provided on the backing layer and/or are at least partially defined by the backing layer. The use of a backing layer provides a backbone running the entire length of the tubular body and therefore provides a degree of structural integrity. Moreover, the use of a backing layer can improve the simplicity of manufacture of these tubular bodies. Where the cells are provided on the backing layer or the backing layer at least partially defines the cells, this further improves the ease of manufacture as the cells, or the remaining parts of the cells, can be manufactured separately and adhered to the backing sheet. In a further embodiment, the plurality of deformable cells are at least partially defined by a cell layer provided on the backing layer. Thus, the cells can be defined by a cell layer or sheet (such as a sheet of material) and adhered to the backing layer. This can make manufacture of the tubular body easier. The sheet can be a single sheet for multiple cells, or a single sheet per cell, for example.

In a further embodiment, the deformable cells are corrugations provided in the cell layer and/or backing layer. For example, the tubular body may be a sheet of corrugated cardboard arranged such that the corrugations run perpendicular to the longitudinal direction.

In another embodiment, the longitudinal wall comprises a continuous wall layer extending along the length of the tubular body in the longitudinal direction and wherein the deformable cells are integrally formed in the wall layer.

In an embodiment, the impact absorbing structure comprises a plurality of the tubular bodies, each of the bodies extending in a longitudinal direction. In some embodiments, the tubular bodies are arranged in the same lateral plane, such that the tubular bodies are parallel to one another. In a further embodiment of this parallel arrangement, at least two tubular bodies are attached to one another so as to form an array of tubular bodies, each of the bodies. This has the advantage that the tubular bodies are held in a fixed position to onte another, which can assist in assembly and in use. In some embodiments of an array, a tubular body may share a sidewall with an adjacent tubular body. For example, a sidewall of one tubular body may also form the sidewall of a second, adjacent tubular body. In this way, a reduced amount of material may be required. In a further embodiment, the outer housing comprises, consists of or consists essentially of a biodegradable material. In addition to or instead of the outer housing, each tubular body may comprise, consist of or consist essentially of a biodegradable material. For example, the biodegradable material may be paper, cardboard or any other woodpulp material; cotton; biodegradable plastic (e.g. Polylactic acid or cellulose); or any other biodegradable material. By biodegradable, it is meant that materials can be decomposed by microorganisms, in particular by bacteria. The invention in these embodiments provides an inexpensive and lightweight box providing means for containing and protecting a package for aerial delivery. Moreover, the impact absorbing structure is suitable for protecting the contents of the hold from impact, while still having a low environmental impact. Accordingly, failure to recover the aerial delivery box will not damage the environment, nor will it be an unnecessary waste of resources, as the box can be designed to be single-use. In an embodiment, the packaging can be manufactured from recycled materials thereby reducing the impact further.

In an embodiment, the housing, the impact absorbing structure and/or each tubular body is formed of cardboard, paper or woodpulp. The invention in this embodiment provides an inexpensive and lightweight box providing means for containing and protecting a package for aerial delivery. The lightweight nature and the structure of the aerial delivery box, as well as the inexpensive nature of the materials, reduces the cost of manufacture compared to existing aerial delivery systems and reduces the environmental impact.

In an embodiment, the housing comprises a plurality of outer walls which define the hold for receiving a payload; and wherein the impact absorbing structure is provided on at least one of the outer walls. The impact absorbing structure may be provided on an internal or external part of the outer wall.

In another embodiment the impact absorbing structure comprises at least two layers, each layer comprising at least one tubular body, optionally a plurality of tubular bodies. In some embodiments, the layers may be spaced apart so as to form a gap. By having a gap between the layers of honeycomb-structured material, the impact absorbing zone is able to deform and crumple to a greater extent. This reduces the likelihood that the force of the impact will travel through the impact absorbing zone and damage the contents of the hold.

In an embodiment, the housing defines the hold such that the walls of the housing form the walls of the hold.

In a second aspect, there is provided an aerial delivery assembly comprising an aerial delivery container as defined in any of the above embodiments, a parachute; and a plurality of shroud lines connecting the parachute to the aerial delivery container. In a third aspect of the invention, the aerial delivery assembly disclosed above can be used to deliver a package.

Brief description of the drawings

Specific embodiments of the invention will now be discussed in detail with reference to the accompanying drawings, in which:

Fig. 1 shows an embodiment of the present invention;

Fig. 2 shows a cross-sectional side view of an impact absorbing structure of an embodiment of the present invention;

Fig. 3 shows a cross-sectional side view of a tubular body according to the present invention;

Fig. 4 shows a cross-sectional top view of an impact absorbing structure of the present invention;

Fig. 5 shows a perspective view of a single tubular body according to the present invention;

Figs. 6a-c show a cross-sectional side view along a longitudinal plane of the deformation of a comparative example of a tubular body without cells;

Figs. 7a-c show a cross-sectional side view along a longitudinal plane of the deformation of a tubular body according to the present invention

Figs. 8a-d show a cross-sectional side views along a longitudinal plane of a plurality of embodiments of a sidewall of a tubular body according to the present invention; and

Fig. 9 shows a cross-sectional top view of an array of tubular bodies according to the present invention.

In the accompanying drawings, like reference numerals refer to like elements. For example, reference numerals 40, 140 and 640 refer to like elements.

Detailed description

Embodiments provide a container or box that can be used to deliver a payload by aerial delivery - e.g. by release from an aircraft, the box having sidewalls, an internal hollow defined by the sidewalls into which the goods can be received and a collapsible or compressible base for reducing or preventing damage to the remainder of the box and the contents of the box. The collapsible or compressible base is provided on a lower face of the box and comprises at least one impact absorbing member or element having sidewalls extending perpendicular to the base, the sidewalls defining a hollow internal region. The impact absorbing member (or where there are plural impact absorbing members, each impact absorbing member) comprises

A first embodiment of the invention is shown in Fig. 1. The air drop system 10 comprises an air drop container 30 having an outer housing 31 and an impact absorbing structure 32. Within the outer housing 31 is an inner hold 34 in which the goods for delivery can be stored. The outer housing 31 of the air drop container 30 consists essentially of corrugated cardboard. The use of corrugated cardboard means that the container is both lightweight and structurally strong. A reduced weight means that the container can be delivered using a smaller parachute and uses fewer resources in manufacture. In the first embodiment the container is a rectangular cuboid and is oriented such that the lower face of the container (i.e. the face most likely to impact the ground first) is a square face. However, alternative embodiments include the container oriented such that a rectangular face is the lower face (see Figure 3), for example, if the load was a particularly heavy load. This orientation increases the size of the impact absorbing structure 32 and therefore provides more protection for the goods. In additional embodiments, the container can be formed of multiple layers of corrugated cardboard and/or can be covered in a clean-burning natural wax or a polymer coating having a nano-scale thickness to provide waterproofing.

In this embodiment, the impact absorbing structure 32 is provided in the lower portion of the air drop container 30 and comprises a cardboard lower housing 33 which is secured to the lower face of the outer housing 31 (i.e. the face of the housing intended to impact the target area). The impact absorbing structure 32 acts as a landing buffer to absorb the shock caused when the container impacts a surface, preferably the target location, thereby reducing damage to the air drop container 30 and the goods inside the container 30. As shown in Figs. 2 to 4, the impact absorbing structure 32 comprises an array of individual tubular bodies 40 provided in the cardboard lower housing 33. Each tubular body 40 is an elongate hollow body having the shape of a triangular prism (see Fig. 5) with an inner hollow section 46 defined by the prism walls. Each tubular body 40 is arranged upright in the lower housing 33 such that the elongate axis (i.e. the longitudinal axis) extends parallel to the longitudinal axis of the container 30 and thus extends in the direction of intended impact (from the lower face of the lower container 33). As can be seen from the top view shown in Fig. 4, the tubular bodies 40 are arranged in a tightly packed arrangement next to each other so as to provide an array of tubular bodies 40. The use of a regular shape, such as a triangular prism, allows the close packing of the tubular bodies 40, which maximises the number of tubular bodies 40 that can be fit into the lower housing 33. This, in turn, increases the amount of resistance to an impact the impact absorbing structure 32 can provide and also reduces the likelihood of failure of the impact absorbing structure 32, which could be caused by misalignment of the tubular bodies 40 if they were not held such that their longitudinal axis was not coaxial with the intended direction of impact.

As can be seen most clearly in Fig. 3, each tubular body 40 is formed of corrugated cardboard with each of the three sides of the triangular prism having an inner paper layer 43 facing inwardly towards the hollow 46, an outer paper layer 43 spaced apart from the inner layer 43 and facing outwardly from the hollow 46, and a corrugated paper layer 44 located between the inner and outer layers 42, 43. The corrugated layer 44 comprises a paper sheet with a plurality of laterally extending corrugations, which corrugations extend horizontally across the width of each side of the triangular prism (i.e. in along an axis perpendicular to the direction of impact/longitudinal axis). The troughs of the corrugations of the corrugated layer 44 relative to the outer layer 43 is then bonded to the outer layer 43. The corrugations of the corrugated layer 44 together with the outer layer 45 thus form a plurality of elongate cells 45 extending in a direction perpendicular to the direction of impact (i.e. the cells 45 extend laterally). As mentioned above, the cells 45 extend across the entire width of each face of each side of the prism shape and, while not shown, they are closed at both ends in the lateral direction by the crimping to seal the corrugated layer 44 to the outer layer. This seals the hollow within each of the cells 45 and thus forms closed cells.

This impact absorbing arrangement provides an efficient and effect means by which the force of the container hitting a surface can be absorbed and mitigated. In fact, this arrangement provides a significant improvement in impact reduction compared to previously employed impact absorbing structures. This is understood to be as a result of the use of the tubular body comprising deformable cells distributed in the longitudinal direction. These cells provide an impact absorbing material which deforms progressively as a force is applied co-linear with longitudinal central axis of the tubular body. In particular, an impact against the container (e.g. when the container hits the ground) causes the deformation of the walls of the tubular body, which in itself absorbs some of the impact of the force applied to the aerial delivery container, and also causes deformation of each cell in the deformable wall, which also further absorbs some of the force caused by the impact. The deformation of each cell will provide a cushioning effect and, since there a plurality of cells distributed along the longitudinal axis, this provides a series of regions along the longitudinal direction in which there is an additional impact absorbing effect. There is also a benefit to using a polygonal or cylindrical tubular body, since the body is strong in the longitudinal direction. Together, these effects increase the time the impact absorbing structure 30 can resist the impact for, as well as reduces the sudden changes in force experienced when the container hits the ground, as compared to existing impact absorbing structures. Moreover, the use of polygonal tubular bodies provides a relatively lightweight and efficient means of providing this impact reduction effect, due to the relatively small amount of material required to produce a high impact resistance. This advantage is amplified by the use corrugated cardboard, which itself is a lightweight material.

As can be further seen from Fig. 1 , the air drop container 30 in this embodiment is connected to a square canopy parachute 20 by shroud lines 21 , the parachute 20 and shroud lines 21 consisting essentially of a tear-resistant wood pulp derivative material, namely air-laid paper. The size of the canopy of the parachute 20 required for the aerial delivery container 30 will primarily depend on the weight, size and fragility of the goods being delivered. A larger parachute 20 will reduce the speed of descent of the system 10. In this embodiment, the system 10 is released from a launch vehicle using parachute extraction as this significantly reduces the forces exerted on the parachute canopy and shroud lines 21. The use of parachute extraction enables the initial snatch force when the parachute 20 catches the air to be controlled by the airspeed of the launch vehicle. Therefore, by reducing airspeed during delivery, the initial snatch force can be substantially reduced. Using parachute extraction also means that the snatch force is separated from the deceleration load, in that the snatch force occurs well before the force experienced when the parachute 20 slows the initial falling speed of the container 30, thereby reducing the total force exerted at the initial drop. In addition, the deceleration load is applied over a longer period of time than would otherwise be experienced with standard drop methods, as the shroud lines 21 are already under tension when the container 30 moves from being in the same horizontal plane as the parachute 20, to being in the same vertical plane as the parachute 20. Additionally, as the parachute 20 is already open when it takes the weight of the container 30, it reduces the distance the load has to fall and accelerate before the parachute takes the full weight, thereby reducing the initial velocity of the system. This allows for the use of a parachute with less reinforcement than might otherwise be required in a system using a standard air drop release method. However, other embodiments of the invention include delivering the aerial delivery system 10 of the first embodiment by other methods of aerial delivery release.

The main components of the air drop system 10 of Figs. 1 to 5 are therefore formed of biodegradable and low-cost materials. This system 10 therefore provides an inexpensive and lightweight means for containing and protecting a package for aerial delivery. The impact absorbing zone is suitable for protecting the contents of the hold from impact while still having a low environmental impact. As a result of this structure, failure to recover the aerial delivery box will not damage the environment, nor will it be an unnecessary waste of resources, as the system can be designed to be single-use. Moreover, in an embodiment, the packaging can be manufactured from recycled materials thereby reducing the impact further. In addition, in another embodiment the materials involved can be inexpensive and delivery can be achieved for significantly less. The typical low cost nature of this embodiment reduces reliance on aerial delivery methods that would cause significant damage upon impact to the landing zone and objects within the landing zone, for example, aerial delivery methods that do not use a parachute (e.g. due to cost). Another advantage of the use of the tubular bodies 40 of this structure is the ease of manufacture and assembly. In some embodiments, the tubular bodies 40 can be manufactured from flat pieces of corrugated cardboard and assembled at the point of loading the goods for delivery into the air drop system 10. This allows large volumes of the tubular bodies to be transported in a flat form, taking up less space than prior art impact absorbing structures (such as honeycomb cardboard). This also allows for much larger tubular bodies to be transported and used without increasing the amount of storage space required relative to prior art systems. The assembly of these components is also relatively easy.

In use of the above air drop system 10, the system 10 will be released from an aircraft, as discussed above. The parachute 20 will be deployed and the system 10 will descend to the target location with the lower housing 33 facing towards the ground. As the container 30 reaches the ground, the lower housing 33 will contact the ground first - the direction of the force of impact will thus be along the longitudinal axis of the container 30 and the tubular bodies 40. On impact, there will be an initial resistance to deformation of the impact absorbing structure 30 until an initial threshold is overcome - i.e. a force sufficient to cause deformation of the lower housing 33 and initial deformation of the tubular bodies 40. One advantage of the present invention is that this force will be lower than for the equivalent design not incorporating cells 45 and so deformation will begin earlier in the impact. As deformation of the impact absorbing structure 32 begins, the sidewalls of the tubular body 40 (formed by outer layer 42 and inner layer 43) begin to deform, followed by the deformation of cells 45. In this embodiment, the lowermost cells 45 will initially deform (i.e. the cells 45 nearest the lower face of the impact absorbing structure 32) and absorb some of the force of the impact. As these cells 45 are deformed, each tubular body 40 will collapse, applying force to cells 45 further away from the lowermost face of the impact absorbing structure 32 and therefore causing these cells 45 to deform. The impact absorbing structure 32 thus continues to absorb the force of the impact until the force has been completely absorbed. While it is possible that cells 45 away from the lowermost face of the impact absorbing structure 32 may deform before those closer to the lowermost face of the impact absorbing structure 32 (e.g. in a non-sequential fashion), for example the uppermost cells 45 (those nearest the hold) may deform before cells 45 equidistance between the upper and lower ends of each tubular body 40, these cells 45 will still provide resistance and this will still be a non-instantaneous collapse of the impact absorbing structure 30 as the cells will deform at different times during the impact. Thus, this will still provide the advantages discussed above and prevent damage to the goods contained within the hold of the housing 31. This may also serve to provide a secondary cushioning effect, by cushioning any force caused by the momentum of goods in the hold of the housing 31 , as will be discussed further below. A more detailed explanation of the deformation of a tubular body is provided below with reference to Figs. 6a-c and 7a-c.

The tubular bodies 40 of Figs. 1 to 5 can be produced by a number of methods. One such method is the construction of the tubular bodies 40 by folding a flat sheet of corrugated cardboard. The folds are formed across the corrugations such that the corrugations form laterally extending cells 45. The ends of the cardboard can then be secured to one another to form the prism shape. In some embodiments, the folds may be pre-formed by machine to assist in accuracy and speed up construction. These methods have the advantage that they provide a simple means by which the effective impact absorbing structure 32 can be formed, using low-cost and environmentally friendly materials.

The mechanism by which deformation of impact absorbing structures can occur will be discussed with reference to Figs. 6a-c, which illustrate the deformation of a tubular body not comprising cells, and Figs. 7a-c which illustrate the deformation of a tubular body of an impact absorbing structure according to the present invention.

Fig. 6a shows a cross sectional view of a tubular body 80 comprising two side walls 82 which are joined (not shown) to form a prism having a hollow 86 therein. The direction of the force of the impact of a landing is depicted by arrow F. As can be seen in Figs. 6b and 6c, as the force F is applied to the tubular body in the longitudinal direction, the sidewalls 82 deform. This is not an immediate, smooth deformation. Instead, the sidewalls 82 will initially resist deformation until a peak force is overcome - i.e. until a certain amount of force is applied that causes the sidewalls 82 to buckle suddenly. This buckling will usually occur at only a small number (or even one) failure points 82' and at this point the tubular body 80 will absorb some of the force of the impact, this protecting any goods in an associated hold. However, once this buckling has occurred, the tubular body 80 will quickly crumple and offer a relatively small amount of resistance since there is little residual strength and impact resistance remaining in the tubular body 80.

This sudden failure mode means that there can be sudden lurching of goods within an associated hold firstly as the tubular body 80 resists the initial deformation, and suddenly afterwards once it has buckled, particularly where the failures 82' are spaced apart from the hold, since there is still a distance the goods must travel before coming to a halt. This can damage the contents therein, particularly where the goods are fragile.

Fig. 7a shows a cross sectional view of a tubular body 140 in accordance with the present invention. Although the complete shape is not shown, the tubular body 140 is a rectangular prism (cuboid) comprising two opposing side walls 141 which have a hollow 146 therebetween. Each of the sidewalls 141 comprises an outer wall 142, an inner wall 143 spaced apart from the outer wall and located on the side of the sidewall 141 facing the hollow 146 and a plurality of cells 145 located therebetween. In this embodiment, the cells 145 are elongate closed cells 145 extending in the lateral direction and which are distributed in the longitudinal direction. The cells 145 in this embodiment are in contact with the adjacent cells in the longitudinal direction such that the entire length of the tubular body 140 in the longitudinal direction comprises an uninterrupted array of cells 145. The direction of the force of the impact of a landing is depicted in Figs. 7a-c by arrow F.

As a force F is applied to the lower end of the tubular body 140, the sidewalls 140 and the lowermost cells 145 are deformed (see deformed cells 145'). The deformation of the cells requires expulsion of the air within them, which in this case requires the rupture of the cell walls 144, which thus provides resistance to the deformation and absorbs some of the impact. In some embodiments, the expulsion of the air from deformed cells 145' causes further resistance where the hollow 146 is sealed, as the air must subsequently be expelled from the hollow 146. As the lowermost cells 45 are deformed, each tubular body 140 will collapse, applying force to cells 145 further away from the source of the force F. This chain of deformation/rupturing of cells 145 causes a cushioning effect which provides an impact absorbing effect over a longer period of time than the sidewalls 82 of the tubular body 80 in Figs. 6a-c. This brings an associated container and goods to a more controlled halt, thus reducing damage.

The arrangement of cells 145 along the longitudinal direction can also provide a secondary cushioning effect. In particular, as a container comes to a halt as it contacts the ground, the momentum of the fall can cause the goods to continue moving, particularly where the impact absorbing structure does not absorb the initial force of the impact quickly enough. This can cause damage to the goods. However, by providing cells along the longitudinal direction, the rearmost cells 145 (i.e. those furthest from the point of impact and closest to an associated hold) can serve to absorb the force caused by the momentum of the goods in the direction opposite force F. In other words, the rearmost cells 145 can deform to prevent damage to the goods caused by movement of the goods relative to the remainder of the container. This will still be effective even in the tubular body 140 has begun deformation at the lowermost end, which would not occur to such an extent in a tubular body without cells (e.g. tubular body 80).

The provision of a number of cells 145 abutting one another in the longitudinal direction or with only a small spacing of less than the height of a cell also serves to improve the stability of the structure of the tubular body, particularly during an impact. This reduces the risk of incomplete deformation by collapse of the tubular bodies, for example caused by lateral movement of the bodies.

While the above embodiments have been described using closed cells located between an inner sheet and an outer sheet, many variations of the arrangement of cells in the tubular bodies are possible while still providing an advantageous arrangement. For example, in one embodiment depicted in Fig. 8a, a sidewall 241 of a tubular body comprises a plurality of spaced apart open cells 245 provided on a backing layer 242. The cells in this embodiment are laterally extending elongate cells 245 in the form of tubular bodies with open ends.

In another embodiment shown in Fig. 8b, a sidewall 341 comprises a plurality of cells

345 formed on a backing layer 342. Each of the cells 345 is individually formed on the backing layer 342 and is spaced apart from the adjacent cells 345.

In another embodiment shown in Fig. 8c, a cross section of a sidewall 441 of a tubular body comprises a plurality of closed cells 445 formed in a layer 442. The cells 445 are thus integral with the layer 442. This can have the advantage of lowering the initial force required to begin deformation of the impact absorbing structure, since there are no cell-free layers in the sidewall 441 which extend the elongate length of the tubular body. Instead, the sidewall 441 comprises a number of deformable lengths of sidewall between two sequential cells. In yet another embodiment, shown in Fig. 8d, a sidewall 541 may comprise a plurality of layers 542, 543 comprising integral cells 545.

A further embodiment is shown in Fig. 9. In this embodiment, a cross-section through an array 600 of tubular bodies 640 is shown. The array 600 is formed of a number of pieces of corrugated cardboard extending in different directions so as to form a series of tubular bodies 640 in a triangular prism shape. Thus, each piece of corrugated cardboard forms a sidewall 641 a, 641 b, 641 c of at least one tubular body 640. In this embodiment, the corrugations of the cardboard pieces form the laterally extending cells (not shown) and the pieces of cardboard are arranged with slots (not shown) so as interlock with one another to form the array. In other embodiments, the cardboard pieces can be secured to one another by another means, such as an adhesive. Arrays, such as that shown in Fig. 9, advantageously allow for easy assembly of impact absorbing structures, particularly large impact absorbing structures, since they can be provided preformed, or in flat pack form, for example.

In addition to different variations of cells, it is also possible to vary the structure and configuration of the impact absorbing structure. For example, as mentioned above, any shape of tubular body can be used, such as a polyhedron, e.g. a self-supporting polygonal cell, or a cylinder. Preferably, the polyhedron is a rectangular prism or, even more preferably a triangular prism. Reducing number of corners (i.e. joins between the flat longitudinal faces of the polygons) further improves the uniformity of deformation as it reduces the opportunity for failure along an edge.

In some embodiments, the arrangement of the tubular bodies can also be modified. For example, where polygonal prism-shaped tubular bodies are used and there are a plurality of tubular bodies in the same lateral plane, the tubular bodies can be arranged such that they abut one another - i.e. in a close packed arrangement. Alternatively, the tubular bodies may be spaced apart from one another.

In the embodiments shown above, the tubular bodies are provided in a lower housing. In other embodiments, a tubular body or tubular bodies may be located within a main housing, e.g. within the hold, or, alternatively or in addition, the tubular bodies may be provided directly on the housing, for example, on the outside of the housing.

In some embodiments, the impact absorbing structure comprises a nested arrangement. In particular, an impact absorbing structure may comprise a plurality of tubular bodies, each of which comprises an additional, narrow tubular body located within the hollow region. This can provide addition impact resistance, for example in the case of heavier loads.

In the embodiment of Fig. 1 , further modifications could be made to the air drop system 10 to make it suitable for different loads. For example, peak stress on the parachute 20 and shroud lines 21 could be reduced by using a smaller parachute. The use of a smaller parachute will depend on the mass of the package, the goods being delivered and the impact absorbing structure as use of a smaller parachute will inevitably result in an increase in the velocity at which the system 10 falls. Therefore, it can only be used if the package will be successfully delivered without being damaged on impact. Reinforcement of the canopy and shroud lines may be required, depending on the force to be applied to the load. The higher the force, the higher the strain along the edges of the canopy and the point at which the canopy attaches to the shroud lines 21 will be. It is along these high stress points that the parachute 20 may require reinforcement. In addition to reinforcing the parachute 20 and shroud lines 21 with additional wood-pulp material, other materials such as cotton or clean- burning or recyclable high-tensile polymers may be used. The parachute 20 may also include a vent (not shown) to increase stability. In this embodiment, reinforcing lines across the parachute 20 from the shroud lines 21 to the centre of the parachute may be used to reduce shear forces.

In another embodiment, the aerial delivery system can comprise a container manufactured consisting essentially of corrugated cardboard with an impact absorbing structure formed of cardboard, in the same manner as that of Fig. 1. However, the parachute 20 consists essentially of an inexpensive biodegradable and recyclable plastic, for example a Polylactic acid (PLA). PLA has the advantages of being relatively cheap, strong and produced using environmentally friendly resources, while being clean burning. Furthermore, PLA can be woven into textile form to strengthen the parachute. This allows the aerial delivery system 10 to be recycled and thus reduces wastage and environmental impact. Furthermore, the use of inexpensive cardboard and plastic components means that the system is a low cost option for the delivery of goods compared to other aerial delivery methods and while having a low environmental impact. In this embodiment, the container can be burned, recycled or left to biodegrade and the plastic parachute can be recycled, burned or left to biodegrade. This has a significantly lower environmental impact than the aerial delivery systems of the prior art. The plastic parachute may also require reinforcement, depending on the goods being delivered. This can be achieved in a similar way to the paper parachute of the first embodiment. In this embodiment, the container 30 is wrapped in a recyclable plastic film (not shown) prior to delivery to provide waterproofing.

In additional embodiments, the impact absorbing structure may be arranged in different configurations to that of the first embodiment. For example, there may be three or more layers of a plurality of tubular bodies, with each layer being located out of alignment with the adjacent layers. By increasing the layers of tubular bodies, additional resistance is provided against the impact and therefore the impact absorbing structure can absorb more damage. In each of these embodiments there may also be hollows formed between the layers giving each impact absorbing layer regions in which to compress onto itself. This allows the impact absorbing structure to absorb the impact of the drop without transferring a significant amount of energy to the hold of the container or the goods within the hold. In one embodiment, the impact absorbing structure is formed with an outside wall formed of corrugated cardboard.

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.