This application claims priority from United Kingdom Patent Application No. 14 00 470.9, filed Jan. 10, 2014, the entire disclosure of which is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a body protection apparatus for absorbing the energy of an impact. The present invention also relates to a method of fabricating a body protection apparatus for absorbing the energy of an impact.
2. Description of the Related Art
Devices for protecting the human body against injury are known. For example, it is known to provide a back protector for motorcyclists such that, in the event of an accident or a fall, injuries to a rider's spine can be reduced or eliminated.
The requirements for a spine protector of this type may be identified as follows. The device should be resilient, in that it should retain its shape so as to remain at its required location and so as to retain its mechanical integrity. However, upon receiving an impact of sufficient energy, the device should absorb this energy. Furthermore, in order to be useable in most environments, the device should be breathable to facilitate heat transfer, to ensure that a user does not become too hot and uncomfortable.
There is provided a body protection apparatus for absorbing the energy of an impact, comprising: an internal planar structure constructed from a plurality of open cells configured to deform under load; and an outer layer of a flexible sheet material arranged to overlie a surface of the internal planar structure, wherein: the outer layer of flexible material is held in place relative to the internal planar structure such that the outer layer of flexible material increases the area of energy absorption under impact.
In an embodiment, the internal planar structure is a honeycomb material comprising a plurality of tubular open cells arranged normally to the surface to be impacted.
There is also provided a method of fabricating a body protection apparatus for absorbing the energy of an impact, comprising the steps of: constructing an internal planar structure from a plurality of open cells configured to deform under load; and arranging an outer layer of a flexible material to overlie a surface of said internal planar structure; wherein the outer layer of flexible material is held in place relative to the internal planar structure such that the outer layer of flexible material increases the area of energy absorption.
In an embodiment, the method includes the further step of forming holes in said flexible material.
A body protection apparatus 101 is shown in
An outer layer of a flexible sheet material 105 is provided having a shape defined by the internal planar structure. The internal planar structure 102 is itself made up from a plurality of cells. Cells at the position of an impact region deform to absorb kinetic energy. In addition, the outer layer of the flexible sheet material draws additional cells into the impact region. In this way, the outer layer extends the size of the impact region so as to increase the number of cells that absorb the kinetic energy. It is then possible for the apparatus to absorb a substantial degree of kinetic energy before the overall integrity of the apparatus breaks down.
Internal planar structure 102 is shown in
In this embodiment, each cell comprises a tube and the tubes are arranged in close packed arrays, such that the gap between adjacent tubes is minimised. Each tube may have a diameter of between two millimetre and nine millimetre (2 mm-9 mm) and a thickness of between zero point one millimetre and zero point seven five millimetre (0.10 mm-0.75 mm). A typical tube length is between ten millimetre and twenty five millimetre (10 mm-25 mm). In this configuration, a progressive buckling failure mode is achieved and a global fracture is avoided if a sufficient number of the tubes are included in the process of material deformation.
In previous applications of the material, it is known to encase the material within a solid outer shell, such as that provided by a motorcyclist's helmet. In this way, the integrity of the apparatus is maintained by the outer shell and the presence of the outer shell ensures that the impact region is extended over a substantially large number of collapsing cells. In the present embodiment, such a shell is not available and the rigidity and structure of the apparatus are provided by the cellular material itself.
Experiments have shown that when used alone, the material may fracture upon the application of a relatively modest impact; given that the progressive buckling property is not observed. However, further experiments have shown that by the inclusion of an outer layer of a flexible sheet material, it is possible to bring a sufficient number of collapsing cells within the influence of the impact, thereby dissipating impact energy without causing a catastrophic failure.
Thus, in an embodiment, the cells are tubes and each tube is welded to at least one other tube. However, in alternative embodiments, alternative structures could be deployed, such as a honey-comb structure, provided that progressive buckling occurs upon impact and the region of buckling is extended by the presence of the planar structure.
An example of an outer layer 301 of a flexible sheet material is shown in
In an embodiment, a layer of adhesive 302 is provided between the internal planar structure and the flexible material. Thus, in an embodiment, a sub-assembly of the apparatus will be constructed as a plurality of layers. A first layer 301 provides a rear flexible material face that is covered by a layer of adhesive 302. The internal planar structure 102 is then applied, followed by a further layer of adhesive and a front flexible material cover.
In an embodiment, a subassembly 404 (constructed from the plurality of layers previously described) is surrounded by an outer rim 402. In an embodiment, the outer rim 402 is constructed from a plastics material and is configured to hold the edges of the layers in place.
In an embodiment, an edge 402 is chamfered, as shown in
In an embodiment, the flexible material 301 is a breathable material, knitted or woven from a yarn. Thus, in this way, at modest expense, it is possible to produce an assembly that has the required mechanical properties, while at the same time presenting holes for breathability and heat transfer.
In an alternative embodiment, the outer layer 301 is a flexible plastic sheet material. To facilitate heat transfer, the flexible sheet material 301 is provided with a plurality of holes 403. In an embodiment, the holes are as large as possible, to enhance breathability, while maintaining sufficient material to retain the required mechanical characteristics.
In the example shown in
In an embodiment, the apparatus of
In an alternative configuration, the apparatus of
The example of
The configuration illustrated in
In response to this, the body protection apparatus absorbs kinetic energy by deforming cells at the position of a region of energy absorption. The apparatus is configured to draw-in additional cells into the region of energy absorption. Thus, in this way, the outer layer extends the size of the impact region so as to increase the number of cells that absorb kinetic energy.
The cells form a solid planar structure that defines the shape of the body protection apparatus. In addition, the planar structure has an impact surface in contact with an outer layer of flexible material having a shape defined by the solid structure to perform the step of extending the impact region, thereby drawing-in additional cells.
It should be appreciated that following an impact of the type shown in
As shown in
A method of fabricating a body protection assembly is shown in
To fabricate the assembly, an internal structure 801 is constructed from a plurality of cells, such that the structure is configured to deform in an area of energy absorption upon receiving an impact.
In an embodiment, the internal structure is constructed by extruding tubes with an internal circumference of a first material and an outer circumference of a second material, in which the second material has a lower melting point than the inner material. Predetermined lengths of the extruded tubes are then cut and arranged into the planar structure of
The tubes may have an outer diameter of between two millimetre and nine millimetre (2 mm-9 mm) and each tube may have a thickness of less than seven hundred and fifty micrometre (750 μm).
Having constructed the internal structure 802, an outer layer of a flexible material 901 is attached to the internal structure. The purpose of the outer layer of flexible material is to bring more of the cells into a region of energy absorption when an impact occurs, thereby increasing the area of energy absorption.
An assembly of layers, consisting of a first flexible material, a layer of adhesive, the internal structure, a further layer of adhesive and a second flexible material is surrounded by an outer rim 1001 of a plastics material. The outer rim holds the layers of the assembly in place and maintains the overall mechanical integrity of the apparatus.
The apparatus shown in
An alternative jacket 1101 is shown in
A glove 1201 is shown in
Number | Date | Country | Kind |
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14 00 470.9 | Jan 2014 | GB | national |