Classifications

• • A—HUMAN NECESSITIES
  • A42—HEADWEAR
  • A42B—HATS; HEAD COVERINGS
  • A42B3/00—Helmets; Helmet covers ; Other protective head coverings
  • A42B3/04—Parts, details or accessories of helmets
  • A42B3/06—Impact-absorbing shells, e.g. of crash helmets
  • A42B3/062—Impact-absorbing shells, e.g. of crash helmets with reinforcing means
  • A42B3/063—Impact-absorbing shells, e.g. of crash helmets with reinforcing means using layered structures
  • A42B3/064—Impact-absorbing shells, e.g. of crash helmets with reinforcing means using layered structures with relative movement between layers

Definitions

• the present disclosure details improvements to protective headgear and, more specifically, to a sheer release layer for integration or securement to headgear such as to the interior of a helmet.
• the sheer release reduces rotational acceleration felt by the brain during an impact to an outside surface of protective headgear.
• an impact diverting mechanism that includes a top layer attached to the shell of the helmet and a bottom layer attached to the liner of the helmet.
• the top layer is disposed adjacent to and mechanically connected to the bottom layer. Upon impact, the top layer shifts and stretches relative to the bottom layer. The sliding and stretching dissipates kinetic energy.
• Golnaraghi et. al. further describes embodiments that have an intermediate layer positioned between the top layer and the bottom layer.
• the intermediate layer may include a liquid-gel lubricant to facilitate relative slipping movement of the top layer and the bottom layer.
• U.S. Patent publication 20130040524 (Halldin et al) titled “Intermediate Layer of Friction Decreasing Material” proposes the use of fibers as friction decreasing material.
• a protective liner in a first embodiment of the invention includes a liner body having a padding layer and a low-friction layer.
• the padding layer faces the body of the user, such as the head, elbow, knee, or shoulder.
• the padding layer may also provide impact absorption, especially from normal forces.
• the padding layer provides comfort to the user interface, such as padding and breathability. It is preferably covered with a thin fabric.
• the low-friction layer is preferably positioned outwardly from the padding layer relative to the user’s body.
• This layer is either positioned under or outside a layer of fabric (or other material).
• a top fabric layer is positioned over the low-friction (i.e., slippery) layer in one preferred embodiment.
• the low-friction layer is an intermediate layer that overlies and is secured to the padding layer positioned on the bottom of the intermediate layer, such as with a helmet.
• the top fabric layer overlies the intermediate layer.
• the top fabric layer has a perimeter and a central portion. The top fabric layer is preferably secured on the perimeter leaving the central portion of the top fabric layer free to accommodate relative sliding movement of the intermediate layer.
• the top fabric layer embodiment provides some distinct advantages.
• the slippery intermediate layer slides freely on fabric. Even when the fabric is secured at the perimeter, the central portion of the fabric still accommodates sliding movement of the slippery intermediate layer. In one preferred embodiment, a limited movement of 5mm to 15mm is sufficient to dissipate a significant amount of the kinetic energy and reduce rotational acceleration of the head to much safer levels in many instances.
• the protective liner is a helmet liner attached to an interior surface of a helmet (such as a bicycle or motorcycle helmet) through the use of hoop-and-loop fasteners, commonly known by the trademark brand name VELCRO®.
• a helmet such as a bicycle or motorcycle helmet
• VELCRO® hoop-and-loop fasteners
• This attachment can be simplified when the top fabric layer can serve as a loop portion of a hook- and-loop fastener and mates with a hook portion of the hook-and-loop fastener secured to the top fabric layer.
• the use of hook-and-loop fasteners improves the sheer release performance of the helmet liner when the top fabric layer serves as the loop portion of the hook-and-loop fastener.
• the hook portion anchors the top fabric layer, which tends to localize the impact force (thus the sliding motion) and also ensures the sliding motion happens optimally in specific locations on the liner.
• the low-friction material is held on a body material with the low-friction layer facing the user.
• the low-friction layer in such embodiment preferably includes a low-friction coating or surface treatment.
• the low- friction layer is positioned beneath a liner material that interfaces with the body of the user.
• the liner material such as a liner having an open-cell foam covered in a thin fabric, bears against the user’s body on one side and bears directly or indirectly against the low-friction material on the other side.
• the low friction material is preferably positioned between such liner and an impact shell, such as a helmet shell or other impact shell such as an elbow, knee, or shoulder guard.
• a further impact layer such as a closed-cell foam layer (e.g., expanded polystyrene (EPS)) can be positioned between the low-friction layer and the shell.
• EPS expanded polystyrene
• a body with further padding or a support layer can be positioned between the low-friction layer and the shell and/or further impact layer.
• the low-friction layer reduces rotational acceleration during an impact to an outside surface of protective gear, such as headgear.
• the body having the low-friction layer is positioned between a head of a person and an inside surface of protective headgear.
• the body has a first face and a second face, with the first face providing a slippery exterior surface.
• the method involves positioning the second face of the body against one of the head or the inside surface of the protective headgear, with the slippery exterior surface on the first face engaging the other of the head or the inside top surface of the protective headgear.
• a sliding movement and material stretching along the slippery exterior surface takes place between the head of the user and the inside top surface of the protective headgear engaging along the slippery exterior surface.
• the rotational acceleration of the head of the user is reduced.
• the sheer-release body does not have a top layer and a bottom layer that slide relative to each other. There is no intermediate sliding layer to assist relative movement of the top layer and the bottom layer. Instead, the body has a slippery exterior surface and facilitates movement to dissipate kinetic energy using this slippery exterior surface.
• the low-friction layer slides under a layer of fabric secured about the low-friction layer.
• the body is secured to the inside surface of the protective headgear and the head of a person slides along the slippery exterior surface.
• the inside surface of the protective headgear slides along the slippery exterior surface.
• a helmet liner (with the head of a person positioned within it) slides along the slippery exterior surface.
• Figure 1 is a schematic diagram illustrating the forces involved in an impact on a protective headgear common to all disclosed embodiments
• Figure 2 is a top plan view of a helmet liner
• Figure 3 is a partial side-elevational view, in section, of a first embodiment illustrating sheer between the protective gear and the user;
• Figure 4 is a partial side-elevational view, in section, of another embodiment showing the basic common components
• Figure 5 is a partial side-elevational view showing a sheer-release body secured to protective gear
• Figure 6 is a partial side-elevational view, in section, of another embodiment using the body of Figure 4; and [0022]
• Figure 7 is a partial side-elevational view, in section, of another embodiment using the body of Figure 4.
• Figure 1 illustrates the force vectors acting upon protective gear when an impact occurs.
• the primary focus of the present invention is the tangential component of the force.
• Protective gear that has long been available having compressible layers, such as crushable EPS foam addresses the normal forces to some extent.
• the present invention principally addresses increased protection for the tangential component of impact forces while also adding some additional protection from normal forces in some embodiments.
• the tangential forces are addressed with various arrangements of a low-friction layer sandwiched with various other layers between the user and the shell of a piece of protective gear.
• a helmet liner identified by reference numeral 10 will now be described with reference to Figures 2 and 3.
• the liner may be formed to fit any particular piece of protective gear, such as a helmet.
• Liner fingers (or other shapes) can be arranged to follow the particulars gear, such as along the inner ridges of a vented bicycle helmet, for example.
• helmet liner 10 has a liner body 12 with multiple layers. When viewed in section, it can be seen that liner body 12 has an impact absorbing bottom layer 15, a low-friction (“slippery”) intermediate layer 17, and atop moveable layer 19.
• Moveable layer 19 is preferably fabric but could alternatively be another layer, such as a thin elastomer layer with properties that allow it slide freely on intermediate layer 17. Fabric of various materials has been found to provide the right properties to create a low-friction interface between low-friction interface with intermediate layer 17. In this preferred embodiment, slippery intermediate layer 17 overlies and is secured to bottom layer 15. Top fabric layer 19 overlies slippery intermediate layer 17.
• top fabric layer 19 has a perimeter 21 and a central portion 23. If secured at all, top fabric layer 19 is secured to either bottom layer 15, slippery intermediate layer 17, or both preferably only at locations along perimeter 21. The securement can be all along the perimeter or just at intermittent locations along the perimeter. This leaves central portion 23 of top fabric layer 19 free to accommodate relative sliding movement of slippery intermediate layer 17. In order to suit most applications, a sliding movement of at least 5mm should be achieved. Some fabrics are inherently more “slippery” and more readily accommodate sliding movement than other fabrics. The selection of the fabric material for top fabric layer 19 can, therefore, impact performance. Where increased sliding movement is desired, a stretchable fabric material may be selected for top fabric layer 19. This enables top fabric layer 19 to facilitate increased sliding movement of slippery intermediate layer 17 as top fabric layer 19 stretches.
• top fabric layer 19 be capable of serving as a loop portion of a hook-and-loop fastener.
• a hook portion 26 of the hook-and-loop fastener mates to the fabric for the purpose of connecting to an interior surface 32of a helmet 30.
• top layer 19 such as a fabric
• top layer 19 is slippery on the intermediate layer, provides the desired amount of movement, and is capable of serving as a loop portion of a hook-and-loop fastener.
• Nylon and spandex blended fabrics as well as polyester and spandex blended fabrics provide beneficial results.
• Various materials are suitable for impact absorbing bottom layer 15, such as a polymer foam and, more particularly, an open- celled polymer foam such as an EVA foam. Certain elastic materials and auxetic materials would also be suitable.
• Various materials are suitable for slippery intermediate layer 15.
• the preferred material is a polymer plastic and, more particularly, a thermoplastic.
• Second fabric layer 25 is adhered to bottom layer 15 for direct contact with a human head.
• Second fabric layer 25 is for the comfort of the wearer and increases the durability of the liner by protecting the open-cell foam of bottom layer 15. Otherwise, second fabric layer 25 does little to contribute to performance of helmet liner 10 in the event of an impact.
• helmet 30 represents atypical piece of protective gear. Helmet 30 is shown as a single layer in the schematic view of Figure 3. However, it will be a layered construction such as in known in the art and may include a hard outer shell with an inner layer of crushable foam such as a closed-cell polystyrene foam. The helmet 30 can have additional layer or layers such as fabric or other impact absorbing materials. For our purposes, all such layers are represented by helmet 30 of Figure 3.
• the exterior surface or shell will immediately accelerate opposite the direction of impact due to the frictional sheer forces applied to the shell.
• the interior surface 32 of helmet 30 will accelerate along with the shell in a direction indicated by arrow 27.
• An acceleration force will likewise be applied to a head 40 of a wearer in the direction indicated by arrow 27.
• helmet liner 10 helps to protect the head 40 of wearer by dissipating kinetic energy such that head 40 does not experience the same degree of acceleration (i.e., impact).
• Top fabric layer 19 is anchored to interior surface 32 of helmet 30 by hook portion 26 of a hook-and-loop fastener, which engages top fabric layer 19. As previously described, top fabric layer 19 serves as the loop portion of the hook-and-loop fastener. Impact absorbing bottom layer 15 with attached slippery intermediate layer 17 abut directly or indirectly against head 40 of the wearer. However, there is relative sliding movement between slippery intermediate layer 17 and top fabric layer 19.
• head 40 is less likely to be concussed or incur other damage due to the impact forces being spread over a longer time interval (i.e., lower acceleration).
• Helmet impact tests were performed using a guided free-fall oblique impact test rig dropping a helmet against an anvil at an impact angle of 45 degrees.
• the impact speed generated was 6.5 meters per second.
• a test was first conducted with a helmet having a standard helmet liner. This established a base line for comparing the performance of the helmet line described above. Tests were conducted in five impact locations and orientations: 1. front, 2. right side toward back, 3. left side toward back, 4. left side toward front, and 5. right side toward front.
• the rotational acceleration percentage reduction achieved by helmet liner 10 was as follows: 1. front an improvement of 22%, 2. right side toward back an improvement of 35%,
• Figure 4 illustrates a body 12.
• body 12 could consist only of polymer plastic portion 14 with low-friction coating or treatment 22 and would not require impact absorbing properties.
• body 12 include an open-celled polymer foam portion 16.
• the open-cell structure provides breathability and improved fit that can enhance comfort.
• Body 12 has a first face 18 and a second face 20.
• First face 18 provides body 12 with a slippery exterior surface. This can be accomplished by using a self-lubricating polymer plastic or, as illustrated here, by applying a coating 22 to a hard polymer plastic layer 14.
• body 12 is secured by mating hook-and-loop tape fasteners, having a hook tape fastener portion 26 and a loop tape fastener portion 28.
• a loop tape fastener portion 28 is secured to second face 20.
• Figure 5 illustrates body 12 positioned between the head 40 of a person and an inside surface 32 of the protective gear, in this instance headgear 30. Second face 20 of body
• the slippery exterior surface will allow up to 15mm of motion, which has proven to be enough to reduce the rotational acceleration of the head by up to 30%.
• open-cell polymer foam portion 16 is preferred, other materials that are known for their impact absorbing properties could be substituted such as closed-cell foams, memory-foams, or other types of shock-absorbing foams.
• hard polymer plastic layer 14 is preferred for slippery exterior surface, other materials could be substituted and coated to provide the desired slippery surface, such as conventional thermoplastic, thermoset elastomers, natural or synthetic rubber, plasticized foams, low-density polyethylene, or high-density polyethylene.
• Preferred coating materials include a matte acrylic coating and a Teflon® (PTFE) coating.
• hook-and-loop tape fasteners are preferred, other types of mechanical fasteners could be used such as buttons, snap fasteners, stitching, adhesives, etc.
• Body 12 is again positioned between the head 40 of a person and an inside top surface 32 of protective headgear 30.
• body 12 serves as a helmet liner and second face 20 of body 12 is positioned against, but not necessarily secured to, head 40.
• the slippery exterior surface on first face 18 engages inside top surface 32 of protective headgear 30.
• the tangential force creates a sliding movement of inside top surface 32 sliding relative to the slippery exterior surface on first face 18.
• body 12 is secured to inside top surface 32 of protective headgear 30 by mating hook tape fastener portion 26 secured to inside top surface 32 with loop tape fastener portion 28 secured to first face 18. The idea is to secure body 12 to a portion of inside top surface 32, such as an edge of a rib, which is not directly facing head 40 and allowing sliding to occur on that portion of inside top surface 32 that is directly facing head 40.
• body 12 is again positioned between the head 40 of a person and an inside top surface 32 of protective headgear 30.
• second face 20 of body 12 is secured to inside top surface 32 of protective headgear 30 by mating hook tape fastener portion 26 secured to inside top surface 32 with loop tape fastener portion 28 secured to second face 20.
• body 12 is secured to inside top surface 32 of protective headgear 30 by mating hook tape fastener portion 26 secured to inside top surface 32 with loop tape fastener portion 28.
• the slippery exterior surface on first face 18 faces head 40 and engages therewith indirectly, by engaging with helmet liner 50 that is secured to head 40. Upon impact, a sliding movement takes between head 40 (along with helmet liner 50) and first face 18 by sliding along the slippery exterior surface on first face 18.
• the embodiments described above share the feature of a low-friction surface sliding in a layered configuration relative to a portion of a human body to be protected from excessive sheer forces causing tangential acceleration.
• the acceleration of the helmet upon impact is greater than that of the body part (e.g., head) being protected.
• the likelihood of injury is reduced.

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• Helmets And Other Head Coverings (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 2021
  • 2021-05-28 CA CA3120169A patent/CA3120169A1/en active Pending
• 2022
  • 2022-05-18 EP EP22803508.5A patent/EP4340669A1/de active Pending
  • 2022-05-18 CN CN202280003285.7A patent/CN115643793A/zh active Pending
  • 2022-05-18 WO PCT/CA2022/050788 patent/WO2022241557A1/en active Application Filing

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