Abstract
The present invention provides a protective headgear having a multi-layered shell to attenuate amplitude of incident mechanical waves of a blunt trauma to a human head by inducing destructive interference with the incident mechanical waves through phase reversal of reflected mechanical waves reflecting off a boundary between two adjacent layers of the protective headgear, and by coaxially converging the phase-reversed reflected mechanical waves with the incident mechanical waves. The multi-layered shell is configured to equally protect people having a similar size of head but with a range of body weight.
Claims
1. A mechanical-waves attenuating protective headgear, comprising: an at-least four-layer shell comprising a polygonal grid fixedly inserted in between an outermost layer and a second layer, and a third layer fixedly adhered to an innermost layer; the polygonal grid, provided as a plurality of polygons of a thermoplastic polymer in a configuration of hemispherical polyhedron, wherein the polygonal grid is configured to have a hardness value higher than that of the outermost layer but lower than that of the second layer; the outermost layer, provided as a closed-cell polymer foam in a configuration of hemispherical bowel shape, wherein an inner wall of the outermost layer is configured to fixedly adhere to the polygonal grid, and wherein the outermost layer is configured to have a hardness value less than that of the second layer; the second layer, provided as a solid polymer plate in a configuration of hemispherical bowel shape, wherein an outer surface of the second layer is configured to fixedly adhere to the polygonal grid, and wherein the second layer is configured to have a highest hardness value of all layers of the at-least four-layer shell; the third layer, provided as an open-cell polymer foam in a configuration of hemispherical bowel shape, wherein the third layer is configured to reversibly adhere to an inner surface of the second layer disposed thereof at a circumferential rim of the at-least four-layered shell, and wherein the third layer is configured to have a lower hardness value than that of the innermost layer; and the innermost layer, provided as a closed-cell polymer foam in a configuration of hemispherical bowel shape, wherein the innermost layer is configured to have a lower hardness value than that of human skull bone.
2. The mechanical-waves attenuating protective headgear according to claim 1, further comprising: a boundary between two adjacent polygons of the polygonal grid comprises a protruding ridge disposed in between the two adjacent polygons, wherein the protruding ridge is provided in a solid longitudinal bar configuration.
3. The mechanical-waves attenuating protective headgear according to claim 2, wherein the solid longitudinal bar configuration of the protruding ridge includes a cross-sectional configuration of an isosceles trapezoid having a longer lower base, a shorter upper base, and a pair of sides of same length with each side connecting the lower base to the upper base.
4. The mechanical-waves attenuating protective headgear according to claim 1, further comprising: the inner wall of the outermost layer, provided in a criss-cross tiled configuration having a plurality of closed-cell polymer foam tiles, wherein a boundary between two adjacent closed-cell polymer foam tiles of the outermost layer comprises a linear groove disposed in between the two adjacent closed-cell polymer foam tiles, and wherein the linear groove is configured to fixedly mate with the protruding ridge of the polygonal grid.
5. The mechanical-waves attenuating protective headgear according to claim 1, further comprising: the third layer, provided over a range of thickness and density of the third layer so as to accommodate a body weight of a person wearing the mechanical-waves attenuating protective headgear, wherein an inner surface of the third layer is fixedly adhered to an outer surface of the innermost layer.
6. The mechanical-waves attenuating protective headgear according to claim 1, further comprising: the innermost layer, provided over a range of thickness and density of the innermost layer so as to accommodate the body weight of the person wearing the mechanical-waves attenuating protective headgear, wherein the outer surface of the innermost layer is fixedly adhered to the inner surface of the third layer.
7. The mechanical-waves attenuating protective headgear according to claim 1, wherein the thermoplastic polymer of the polygonal grid has a Rockwell R hardness value ranging from 70 to 140.
8. The mechanical-waves attenuating protective headgear according to claim 1, wherein the closed-cell polymer foam of the outermost layer has a 25% indentation force deflection value of higher than 45, a foam support factor of higher than 3.0, and a Rockwell R hardness value ranging from 70 to 140.
9. The mechanical-waves attenuating protective headgear according to claim 1, wherein the solid polymer plate of the second layer has a Rockwell R hardness value of higher than 140.
10. The mechanical-waves attenuating protective headgear according to claim 1, wherein the open-cell polymer foam of the third layer has a 25% indentation force deflection value of higher than 45, a foam support factor of between 1.5 and 3.0, and a Shore D scale hardness value of at least 10 below a Shore D scale hardness value of the innermost layer.
11. The mechanical-waves attenuating protective headgear according to claim 1, wherein the closed-cell polymer foam of the innermost layer has a 25% indentation force deflection value of higher than 45, a foam support factor of higher than 3.0, and the Shore D scale hardness value of between 65 and 90.
12. The mechanical-waves attenuating protective headgear according to claim 3, further comprising: the protruding ridge of the polygonal grid, wherein the protruding ridge is configured to be fixedly inserted in the linear groove of the outermost layer, and wherein a lower base of the protruding ridge of the polygonal grid is configured to be fixedly attached to the outer surface of the second layer.
13. The mechanical-waves attenuating protective headgear according to claim 3, further comprising: the protruding ridge in the cross-sectional configuration of the isosceles trapezoid is provided over a range of a cross-sectional base angle of the isosceles trapezoid.
14. The mechanical-waves attenuating protective headgear according to claim 4, wherein the closed-cell polymer foam tiles of the inner wall of the outermost layer are fixedly adhered to the outer surface of the second layer.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 shows a schematic presentation of a mechanical-waves attenuating protective headgear.
[0017] FIG. 2A represents a schematic view of an outermost layer; FIG.2B shows a schematic see-through view of the outermost layer; FIG. 2C shows a schematic view of a polygonal grid.
[0018] FIG. 3A illustrates a schematic view of a second layer; FIG. 3B shows a schematic example of an inner layer comprising a third layer adhered to an innermost layer.
[0019] FIGS. 4A-4D depict schematic exploded views of an at-least four-layered shell of the mechanical-waves attenuating protective headgear: FIG. 4A illustrates a schematic example of the inner layer comprising the third layer and the innermost layer; FIG. 4B shows a schematic example of the second layer; FIG. 4C shows a schematic example of the polygonal grid; FIG. 4D shows a schematic example of the outermost layer.
[0020] FIG. 5 illustrates a schematic coronal view of stacked-up layers of the at-least four-layered shell of the mechanical-waves attenuating protective headgear, having the polygonal grid inserted in between the outermost layer and the second layer.
[0021] FIG. 6A illustrates a schematic depiction of a blunt trauma with an incident mechanical three-dimensional force having incident mechanical waves hitting the outermost layer and the second layer of the mechanical-waves attenuating protective headgear without the polygonal grid in between the outermost layer and the second layer; FIG. 6B shows a reflected mechanical three-dimensional force having reflected mechanical waves radially reflecting off the outermost layer and the second layer.
[0022] FIG. 7A shows a schematic illustration of a blunt trauma with an incident mechanical three-dimensional force having incident mechanical waves hitting the outermost layer and the second layer of the mechanical-waves attenuating protective headgear with the polygonal grid in between the outermost layer and the second layer; FIG. 7B shows a reflected mechanical three-dimensional force having reflected mechanical waves coaxially converging with the incident mechanical three-dimensional force having the incident mechanical waves after reflecting off the outermost layer and the second layer.
[0023] FIGS. 8A-8C show schematic examples of a cross-sectional configuration of protruding ridges of the polygonal grid and points of reflection of incident mechanical three-dimensional force.
[0024] FIGS. 9A-9C show schematic examples of variable thickness and density of the third layer and the innermost layer.
DETAILED DESCRIPTION OF THE DRAWINGS
[0025] As described below, the present invention provides a mechanical-waves attenuating protective headgear. It is to be understood that the descriptions are solely for the purposes of illustrating the present invention, and should not be understood in any way as restrictive or limited. Embodiments of the present invention are preferably depicted with reference to FIGS. 1 to 9, however, such reference is not intended to limit the present invention in any manner. The drawings do not represent actual dimension of devices, but illustrate the principles of the present invention.
[0026] FIG. 1 shows a schematic presentation of a mechanical-waves attenuating protective headgear which comprises a dome portion 1 covering the majority of a head including frontal, parietal, sphenoid, occipital and temporal regions of a human head, a lower circumferential rim 2 covering a portion of zygomatic arch and mastoid protuberance of the human head, and an inner layer 3. The dome portion is provided in a hemispherical bowel shape. The inner layer 3 is configured to be reversibly attachable to an inner surface of the dome 1.
[0027] FIG. 2A represents a schematic view of an outermost layer comprising an outer wall 4 and an inner wall 5. FIG.2B shows a schematic see-through view of the inner wall 5 comprising a plurality of planar tiles 6 arranged in a criss-cross configuration. In between two adjacent planar tiles 6 of the inner wall 5, a linear groove 7 is provided. FIG. 2C shows a polygonal grid comprising a plurality of polygons 9 in a configuration of a hemispherical polyhedron. A plurality of the polygons adjoin each other along a border between two adjacent polygons, wherein the border between the two adjacent polygons of the hemispherical polyhedron is configured to be raised to form an outwardly protruding ridge 8. Each planar tile 6 of the inner wall 5 of the outermost layer shown in FIG. 2B is configured to fill up a space of each polygon 9. The protruding ridge 8 of FIG. 2C is configured to fixedly mate with the linear groove 7 of the inner wall 5 of FIG. 2B. The outermost layer comprise a closed-cell polymer foam having a measurable thickness ranging from 0.2 inches to 2.0 inches, which is configured to be compressible and depressibly deformable by an impact of a blunt trauma at an angle to a planar surface of the outermost layer. The closed-cell polymer foam of the outermost layer has a 25% indentation force deflection value of higher than 45, a foam support factor of higher than 3.0, and a Rockwell R value ranging from 70 to 140.
[0028] FIG. 3A shows a schematic view of the second layer 10 in a hemispherical bowel shape. Referring to FIG. 4B, an outer surface 15 of the second layer 10 is adherently enclosed by a plurality of the planar tiles 6 of the inner wall 5 of FIG. 2B, and fixedly attached to the protruding ridge 8 of the polygonal grid of FIG. 2C. The second layer comprises a solid plate in the hemispherical bowel shape having a measurable thickness ranging from 0.1 inches to 1.0 inches, which is made of hard polymers having a Rockwell R value of higher than 140 and configured to be undeformable to the impact of the blunt trauma at an angle to a planar surface of the second layer over a gravitational force of up to 300 g+30 g (10% S.D.) and over a range of temperature from 0 F. to 175 F. without material failure.
[0029] FIG. 3B shows a schematic view of the inner layer 3 having a plurality of planar tiles 11 comprising a third layer 12 tightly adherent to an innermost layer 13. An outer circumferential portion of the inner layer 3 is configured to be reversibly attachable to a portion of the lower circumferential rim 2 of FIG. 1. The third layer 12 comprises an open-cell polymer foam having a measurable thickness ranging from 0.2 inches to 2.0 inches, which is configured to be compressible and depressibly deformable by the impact of the blunt trauma at an angle to a planar surface of the third layer. The open-cell polymer foam of the third layer has a 25% indentation force deflection value of higher than 45, a foam support factor of between 1.5 and 3.0, and a hardness of a Shore D scale value of at least 10 below the Shore D scale value of the innermost layer 13. The innermost layer comprises a closed-cell polymer foam having a measurable thickness ranging from 0.2 inches to 2.0 inches, which is configured to be compressible and depressibly deformable by the impact of the blunt trauma at an angle to a planar surface of the innermost layer. The closed-cell polymer foam of the innermost layer has a 25% indentation force deflection value of higher than 45, a foam support factor of higher than 3.0, and a hardness of a Shore D scale value of between 65 and 90. The inner surface 16 is configured to enclosably cover an area of the human head comprising a part of the frontal, the entire parietal, a majority of the temporal region and a majority of the occipital region.
[0030] FIGS. 4A-4D depict schematic exploded views of an at-least four-layered shell of the mechanical-waves attenuating protective headgear. Shown in FIG. 4A, the planar tile 11 comprises the third layer 12 tightly adherent to the innermost layer 13. A fenestration 14 can be provided for ventilation through the planar tile 11. FIG. 4B shows the second layer 10 having the outer surface 15 and an inner surface 16. A fenestration 17 can be provided for ventilation through the second layer 10, corresponding to the fenestration 14 of the planar tile 11 of the inner layer of FIG. 4A. FIG. 4C shows the polygonal grid comprising a plurality of the polygons 9, with each polygon surrounded by the protruding ridge 8. A fenestration portion 18 can be provided, corresponding to the fenestration 14 of the planar tile 11 of the inner layer of FIG. 4A and the fenestration 17 of the second layer of FIG. 4B. FIG. 4D shows the outermost layer comprising the outer wall 4 and the inner wall 5. An outer surface 19 of the outer wall is configured as a smooth convex hemispherical surface. An inner surface 20 of the planar tile 6 is configured to tightly adhere to the outer surface 15 of the second layer 10. The linear groove 7 disposed in between two adjacent planar tiles 6 is configured to fixedly mate with the protruding ridge 8 of FIG. 4C. A fenestration 21 can be provided for ventilation through the outermost layer, corresponding to the fenestration 14 of the planar tile 11 of the inner layer of FIG. 4A, the fenestration 17 of the second layer of FIG. 4B and the fenestration portion 18 of the polygonal grid of FIG. 4C.
[0031] FIG. 5 illustrates a schematic coronal view of stacked-up layers of the at-least four-layered shell of the mechanical-waves attenuating protective headgear. The outermost layer having the inner wall 5 and the outer wall 4 covered by the outer surface 19 in a configuration of the smooth convex hemispherical surface adheres tightly to the second layer 10 so as to facilitate reflection of incident mechanical waves off a boundary between the inner surface 20 of the outermost layer shown in FIG. 4D and the outer surface 15 of the second layer 10 shown in FIG. 4B. In between the outermost layer 4-5 and the second layer 10, the polygonal grid with protruding ridges 8 is fixedly inserted. The inner surface 16 of the second layer 10 shown in FIG. 4B is tightly placed in contact with an outer surface of the third layer 12. There is no adhesion between the second layer 10 and the third layer 11 except a portion of the lower circumferential rim 2 which is configured to be reversibly attachable to an outer circumferential portion of the third layer 12, which is to facilitate air movement in and out of open cells of the open-cell polymer foam of the third layer 12. The third layer 12 is adherently attached to the innermost layer 13 having an inner surface 22. The inner surface 22 is configured in a hemispherical bowel shape so as to accommodate a dome shaped human head.
[0032] FIG. 6A illustrates a schematic depiction of a blunt trauma with an incident mechanical three-dimensional force 23 having incident mechanical waves 24 centripetally hitting the outermost layer 4-5 and the second layer 10 of the mechanical-waves attenuating protective headgear without the polygonal grid in between the outermost layer 4-5 and the second layer 10. Shown in FIG. 6B, a part of the incident mechanical three-dimensional force 23 having the incident mechanical waves 24 is reflecting off a boundary between the outermost layer 4-5 and the second layer 10 as a reflected mechanical three-dimensional force 25 having reflected mechanical waves 26-28. The reflected mechanical waves 26-28 are out of phase with the incident mechanical waves 24 since hardness of the outermost layer 4-5 is less than that of the second layer 10, thereby reducing an amplitude of the incident mechanical three-dimensional force 23 having the incident mechanical waves 24. Around a center of a site of the blunt trauma by the incident mechanical three-dimensional force 23 having the incident mechanical waves 24, a part of the reflected mechanical three-dimensional force 25 having the reflected mechanical waves 26 coaxially spreads back along a longitudinal axis of the incident mechanical three-dimensional force 23 having the incident mechanical waves 24. Due to a spherical contour of the outermost layer 4-5 and the second layer 10 of the mechanical-waves attenuating protective headgear, other parts of the reflected mechanical three-dimensional force 25 reflecting off outside the center of the site of the blunt trauma spread in a widespread radially scattered pattern, producing the reflected mechanical waves 27 and 28. Consequently a force field of the reflected mechanical three-dimensional force 25 is more radially spread than coaxially concentrated, thus diminishing efficiency of the reduction of the incident mechanical three-dimensional force 23 by the reflected mechanical three-dimensional force 25.
[0033] FIG. 7A shows a schematic illustration of a blunt trauma with an incident mechanical three-dimensional force 29 having incident mechanical waves 30 centripetally hitting the outermost layer 4-5 and the second layer 10 of the mechanical-waves attenuating protective headgear with the polygonal grid having protruding ridges 8 in between the outermost layer 4-5 and the second layer 10. Shown in FIG. 7B, a part of the incident mechanical three-dimensional force 29 having the incident mechanical waves 30 is reflecting off a boundary between the outermost layer 4-5 and the second layer 10 and the protruding ridges 8 of the polygonal grid as a reflected mechanical three-dimensional force 31 having reflected mechanical waves 32-34. The reflected mechanical waves 32 is out of phase with the incident mechanical waves 30 since the hardness of the outermost layer 4-5 is less than that of the second layer 10. Similarly, the reflected mechanical waves 33-34 reflecting off the protruding ridges 8 arc out of phase with the incident mechanical waves 30 since the hardness of the protruding ridges 8 is higher than that of the outermost layer 4-5. These phase-reversed reflected mechanical waves 32-34 merge with the incident mechanical waves 30, thereby reducing an amplitude of the incident mechanical three-dimensional force 29 having the incident mechanical waves 30. Similar to a sequence of events shown in FIG. 6A-6B, around a polygonal center of a site of the blunt trauma by the incident mechanical three-dimensional force 29 having the incident mechanical waves 30, a part of the reflected mechanical three-dimensional force 31 having the reflected mechanical waves 32 coaxially spreads back along a longitudinal axis of the incident mechanical three-dimensional force 29 having the incident mechanical waves 30. Other parts of the reflected mechanical three-dimensional force 31 having the reflected mechanical waves 33-34 reflecting off edges of the protruding ridges 8 spread spherically in a centrifugal direction away from the edges of the protruding ridges 8. The reflected mechanical waves 33-34 reflecting off the edges of the protruding ridges 8 spherically cluster around the protruding ridges 8 of a polygon of the polygonal grid, while spreading in the centrifugal direction. Combination of the reflected mechanical waves 33-34 with the reflected mechanical waves 32 produces a narrow, coaxially converging field of the reflected mechanical three-dimensional force 31. The coaxial convergence of the reflected mechanical three-dimensional force 31 having the reflected mechanical waves 32-34 with the incident mechanical three-dimensional force 29 having the incident mechanical waves 30 enhances the efficiency of reduction of the incident mechanical three-dimensional force 29 having the incident mechanical waves 30.
[0034] FIG. 8A shows a schematic example of a rectangular cross-sectional configuration of a protruding ridge 8 having a base angle 39 of 90, a side 35 and an edge 36 as an example, embedded between the outermost layer 4-5 and the second layer 10. A first part of an incident mechanical three-dimensional force 37 to a boundary between the outermost layer 4-5 and the second layer 10 is reflected off coaxially as a reflected mechanical three-dimensional force 38. A second part of the incident mechanical three-dimensional force 37 to the edge 36 is reflected tangentially off as a reflected mechanical three-dimensional force 40, heading toward a longitudinal axis of the incident mechanical three-dimensional force 37. A third part of the incident mechanical three-dimensional force 37 to the side is reflected off as a reflected mechanical three-dimensional force 42 at a right angle to the side. If a pair of the protruding ridges of a polygon are arranged in a mirror image to each other, the reflected mechanical three-dimensional force 40 is mirrored as a reflected mechanical three-dimensional force 41; the reflected mechanical three-dimensional force 42 is mirrored as a reflected mechanical three-dimensional force 43.
[0035] FIG. 8B shows a schematic example of an isosceles trapezoid cross-sectional configuration of a protruding ridge 44 having an acute base angle 49, an obtuse side 45 and an edge 46 as an example, embedded between the outermost layer 4-5 and the second layer 10. A first part of an incident mechanical three-dimensional force 47 to a boundary between the outermost layer 4-5 and the second layer 10 is reflected off coaxially as a reflected mechanical three-dimensional force 48. A second part of the incident mechanical three-dimensional force 47 to the edge 46 is reflected tangentially off as a reflected mechanical three-dimensional force 50, heading toward a longitudinal axis of the incident mechanical three-dimensional force 47. A third part of the incident mechanical three-dimensional force 47 to the obtuse side is reflected off as a reflected mechanical three-dimensional force 42 at a right angle to the obtuse side, directing the reflected mechanical three-dimensional force 52 toward the longitudinal axis of the incident mechanical three-dimensional force 47 away from the boundary between the outermost layer 4-5 and the second layer 10. If a pair of the protruding ridges 45 of a polygon are arranged in a mirror image to each other, the reflected mechanical three-dimensional force 50 is mirrored as a reflected mechanical three-dimensional force 51; the reflected mechanical three-dimensional force 52 is mirrored as a reflected mechanical three-dimensional force 53.
[0036] FIG. 8C shows a schematic example of an isosceles trapezoid cross-sectional configuration of a protruding ridge 54 having an acute base angle 56, an obtuse side 55 and an edge 57 as an example, embedded between the outermost layer 4-5 and the second layer 10. The acute base angle 56 of FIG. 8C is more acute than the acute base angle 49 shown in FIG. 8B. A first part of an incident mechanical three-dimensional force 58 to a boundary between the outermost layer 4-5 and the second layer 10 is reflected off coaxially as a reflected mechanical three-dimensional force 59. A second part of the incident mechanical three-dimensional force 58 to the edge 57 is reflected tangentially off as a reflected mechanical three-dimensional force 60, heading toward a longitudinal axis of the incident mechanical three-dimensional force 58. A third part of the incident mechanical three-dimensional force 58 to the obtuse side is reflected off as a reflected mechanical three-dimensional force 62 at a right angle to the obtuse side, directing the reflected mechanical three-dimensional force 62 toward the longitudinal axis of the incident mechanical three-dimensional force 58 further away from the boundary between the outermost layer 4-5 and the second layer 10. If a pair of the protruding ridges 54 of a polygon are arranged in a mirror image to each other, the reflected mechanical three-dimensional force 60 is mirrored as a reflected mechanical three-dimensional force 61; the reflected mechanical three-dimensional force 62 is mirrored as a reflected mechanical three-dimensional force 63.
[0037] FIG. 9A represents a schematic example of a piece of the third layer 12 and the innermost layer 13 in a configuration of a planar tile 11 having a baseline thickness and density. FIG. 9B shows a schematic example of a thicker third layer 64 than the third layer 12 of FIG. 9A. FIG. 9C illustrates a schematic example of a thicker and denser third layer 66 and a thicker and denser innermost layer 65 than the third layer 12 and the innermost layer 13 of FIG. 9A, respectively.
[0038] It is to be understood that the aforementioned description of the apparatus is simple illustrative embodiments of the principles of the present invention. Various modifications and variations of the description of the present invention are expected to occur to those skilled in the art without departing from the spirit and scope of the present invention. Therefore the present invention is to be defined not by the aforementioned description but instead by the spirit and scope of the following claims.
