WO2013131146A1

WO2013131146A1 - Helmet undergarment

Info

Publication number: WO2013131146A1
Application number: PCT/AU2013/000233
Authority: WO
Inventors: Lachlan Thompson; Sinnappoo KANESALINGAM
Original assignee: Rmit University
Priority date: 2012-03-09
Filing date: 2013-03-12
Publication date: 2013-09-12

Abstract

The invention is a thin textile garment worn between the head and the motorcycle helmet. The garment forms an independent secondary liner between the helmet and the rider's head and looks in appearance like a balaclava. The garment is made of a material which has a central layer of water absorbent material with the inner surface in contact with the wearer's head being hydrophobic so that it is dry to the touch and the outer surface in contact with the air stream being hydrophilic to allow evaporative cooling from the water retention layer. The absorbency and thickness of the water retention layer may be selected to provide a predetermined period for cooling preferably an hour's cooling or more depending on conditions. The water absorbent liner is composed of microfibres.

Description

HELMET UNDERGARMENT

This invention relates to a head garment to be worn under a motorcycle helmet and particularly to a cooling device for helmets worn on open vehicles. Background to the invention

motorcycle helmets, particularly for motorcycles, are an essential safety item for riders. Helmets generally have the disadvantage of retaining heat. 20% of the bodies heat is lost through the head and in hot weather this can easily lead to overheating inside a helmet. The problem of dealing with cooling of helmets has been addressed.

USA patent 5557807 discloses a cap having pouches for a coolant.

USA patent 5839121 discloses a cycling cap having ventilation funnels to take air from the front of the cap over the scalp.

USA patent 6243876 discloses a cap having triangular vents at the front and sides and rectangular openings at the rear.

USA patent 7028344 discloses a liner for a helmet in which the liner contains pockets for a coolant.

USA patent 7114194 discloses a work helmet with a plenum for ventilation which includes a fan.

USA patent 7559094 discloses a cap with a complex cooling arrangement of pockets of coolant and ventilation openings.

USA patent application 20080276340 discloses a cooling cushion for military helmets.

It is an object of this invention to provide an inexpensive and convenient means for cooling helmets

Brief description of the invention.

To this end the present invention provides a head garment adapted to be worn under a helmet said garment being shaped to cover the top of the head and the ears as well as the nape of the neck of the wearer in which the garment is made of a material which has a central layer of water absorbent material with the inner surface in contact with the wearers head being hydrophobic and the outer surface in contact with the air stream being hydrophilic. This invention is predicated on the discovery that conventional motorcycle helmets have relatively poor sealing adjacent the ears and the nape of the neck (at the back of the head) and that there is a region of low pressure adjacent the ears and a region of high pressure adjacent the nape of the neck.

Heat stress caused by the wearing of bike helmets (particularly motorcycle helmets) is reduced in this invention by the provision of a balaclava like head garment that covers the top of the head and the ears as well as the nape of the neck of the wearer. Poor sealing between the head and the helmet at the ears and nape of the neck allows for air flow out of and into the helmet respectively, at these sites. This allows air flow inside the helmet between the inside of the helmet and the garment. The garment is made of a material which has a central layer of water absorbent material with the inner surface in contact with the wearer's head being hydrophobic so that it is dry to the touch and the outer surface in contact with the air stream being hydrophilic to allow evaporative cooling from the water retention layer. The absorbency and thickness of the water retention layer may be selected to provide a predetermined period for cooling preferably an hour's cooling or more depending on conditions.

In this invention a thin textile garment is worn between the head and the motorcycle helmet. The garment forms an independent secondary liner between the helmet and the rider's head and looks in appearance like a Balaclava. Preferably the water absorbent liner is composed of microfibres.

A range of textile designs are suitable for the hydrophilic layer. Synthetic yarns such as polyester or nylon are extruded in the form of a triangular cross section. The twisting of the fibres to form the yarn results in micro capillary tracks which facilitate the transfer of moisture. The fibre thickness, number of fibres and tightness of twist are optimised in this application for moisture transport.

Commercial yarns available for this purpose include Coolmax from Dupont.

For this application, the fabric woven from the yarns must be hydrophilic to move away moisture from the skin interface and spread the limit on the largest possible area to favour evaporation.

To increase the moisture transfer and evaporation the fabric preferably should be of a "brushed" fabric providing the maximum possible surface area thus enhancing the comfort level and cooling duration. Hydrophobic fibres have a "low surface energy" this results in the water molecules sitting on the surface of the fabric. The low molecular attraction between the water molecules and the molecules of the surface of fabric are such that the water tension of the droplet is not attracted to the fibre and so "rolls off' the fabric surface.

Polyester a fibre that is hydrophobic in nature is suitable for the invention.

Commercial examples include Sorona by Dupont others include Dacron also by Dupont.

The cooling system is based on a thermo-syphons process using the

water/moisture trapped within the micro fibre layers of the liner to transfer heat from inside the helmet around the rider's head to the outside air. This evaporative process lowers the rider's head temperature and can provide adequate cooling for over one hour. The novelty is that the liner can be reused when it stops cooling by immersion of the liner in water for a short time period to refill the microfibre structure then wringing out excess water entrapping air.

Detailed description of the invention

A preferred embodiment of the invention will now be described with reference to the drawings in which:

Figure 1.shows a cross sectional view of the liner of this invention inside a motorcycle helmet;

Figure 2 shows the liner surface inside the helmet;

Figure 3. shows the structural layers of the liner;

Figure 4 shows the internal airflow inside of a moving motorcycle helmet.

Referring to figures 1 and 2 the core feature of the invention is the wearing and enclosing of the liner between the rider's head and the helmet. The invention also depends on selection and application of the arrangement of the hydrophobic layer which is worn against the rider's head/skin which due to the water repellent nature of this layer the rider wearer feels as a dry layer, then the inner water/moisture retaining microfibre material and the liner in contact with the helmet which is a breathable (hydrophilic) material. The fabric holds water /moisture within the microfibre structure and despite wringing of the fabric the water retention remains high. The purpose of the wringing action is to manage the weight of the liner, the rider has the option to wring the liner tightly and have a shorter cooling time or leave the liner saturated (which the rider feels as a dry) and extend the cooling time. To improve evaporative cooling for the motorcyclist a section of the liner is styled to provide an area that is exposed to the outside air when worn. This section can be folded back into the helmet if the cooling rate is too high. Note that the liner may be styled to not cover the chin and face area of the rider and still be effective. As shown in figure 3 the liner is composed of three layers which consist of, a hydrophobic (water repellent) breathable layer against the wearers skin/hair; an inner layer of superabsorbent structure composed of hydrophilic (attract water) fibres and hydrophobic fibres (fibres that reject water) comingled into a fibrous core; and a moisture conductive layer in contact with the helmet giving a moisture vapour transmission lining on the helmet side of the liner.

Filaments are preferably extruded in a triangular cross section. Preferably the filaments are then cut and made into staple fibres. Preferably the fibres are then combined by twisting to make the yarn for the fabric. The size and twist is preferably optimised for water retention (tighter twist suits lower surface tension fluids).

The fabric may be coated with a water-resistant finish which further intensifies the hydrophobic nature. Other materials for the hydrophobic fabric include fibres from, fluorinated polymers or polyfluorotetraethylene (PTFE), fluoroalkylsilanes, and per- fluorinated polymer monofilaments. This includes the use of these fluorinated polymers as a coating on the polyester during the extrusion of the polyester filament resulting in an enhanced or ultra-hydrophobic fibre.

The inner layer uses a combination of comingled random hydrophilic and

hydrophobic fibres in a batting layer. The batting consists of a blend or mixture of hydrophilic and hydrophobic fibres in a non-woven batting (loosely mixed). The hydrophilic fibres hold the moisture inside the batting layer, without causing wetness on to the wearer. Materials used for the batting are preferably

polyacrylonitrile/polyacrylate hydrophilic fibres blended with polyester (the hydrophobic fibre).

Commercial examples include: polyacrylamide copolymer, ethylene maleic anhydride copolymer, cross-linked carboxymethylcellulose alcohol copolymers, cross-linked polyethylene oxide, starch grafted copolymer of polyacrylonitrile. Before wearing, the liner is immersed in water for a set time period. When immersed, water is absorbed into the inner layer of hydrophilic fibres of the layer which become saturated with moisture. At which time the liner is removed from the water and excess water removed by wringing. The hydrophobic fibres then distribute the water and surround the moistened fibres with air pockets, creating the mechanism for evaporation. As the liner absorbs heat from the wearer's head in contact with the liner, the entrapped moisture transitions into the vapour phase to provide uniform cooling over the wearers head. Additional cooling is facilitated by a section of the liner that is exposed below the helmet. The application of comingled hydrophilic and hydrophobic fibres ensures that the liner is thin, yet able to maximise the duration of water retention and hence duration of cooling.

This invention differs from the prior art in that cooling is provided as a layer between the wearer and the helmet.

As shown in figure 4 this invention utilises the natural airflow over the sealed helmet "D" i.e. visor can be closed. The rider moving forward creates an air flow "C" over the helmet. At the front of the helmet "C" and at the rear "B" there is a high pressure zone created by the airflow. All motorcycle helmets have an air cavity "F" around the face and importantly at the ears "A" the airflow "C: moves rapidly over the helmet and produces a low pressure zone (Bernoulli affect) around the ears "A". The pressure difference between the high pressure at "B" and the low pressure at "A", results in an internal airflow within the helmet. Outside air entering at "B" moving over the riders head "E" around their ears and exiting at "A".

A rider wearing the helmet liner of this invention will benefit from this cooling airflow. The shape of the liner is critical in the effectiveness of the cooling operation and must be shaped to ensure an enhancement of the airflow around the helmet. Due to the need for standards compliance, the uniformity of existing helmets facilitates a single design cooling liner.

This invention does not compromise compliance with helmet safety standards. This invention is compatible with all current standards compliant helmets for motorcycling and motorsport.

It is important to note that the saturated liner of this invention appears and feels dry when on the rider's head making the device comfortable to wear in high heat. The liner of this invention may be reused many times by immersion in water for a short time period to facilitate saturation of the liner material, when the cooling effect is exhausted.

Those skilled in the art will realise that this invention provides a unique and inexpensive solution to the problem of cooling a motorcycle rider's head wearing a motorcycle helmet. Those skilled in the art will also realise that this invention may be implemented in embodiments other than those described without departing from the core teachings of the invention.

Claims

1. A head garment adapted to be worn under a helmet said garment being

shaped to cover the top of the head and the ears as well as the nape of the neck of the wearer in which the garment is made of a material which has a central layer of water absorbent material with the inner surface in contact with the wearer's head being hydrophobic and the outer surface in contact with the air stream being hydrophilic.

2. A garment as claimed in claim 1 in which the inner layer uses a combination of randomly comingled hydrophilic and hydrophobic fibres.

3. A garment as claimed in claim 1 or 2 in which the hydrophobic material is selected from polyester, fluorinated polymers including PTFE, fluoro-alkyl- silanes, and per-fluorinated polymer monofilaments and mixtures thereof.

4. A garment as claimed in claim 1 or 2 in which the hydrophyllic material is selected from polyacrylonitrile, polyacrylate, polyacrylamide copolymer, ethylene maleic anhydride copolymer, cross-linked carboxymethylcellulose alcohol copolymers, cross-linked polyethylene oxide, starch grafted copolymers of polyacrylonitrile and mixtures thereof.