NZ502867A - Foam layers and a garment comprising polypropylene foam layers of different densities - Google Patents

Abstract

Described is a body protector, preferably a vest. The vest (1) has two arm cut-away portions (2) and a neck aperture (3) and a crotch strap (4). The vest has a cloth outer layer (7) covering a foam construct beneath. The foam construct has two layers of different densities.

Description

02867 BODY PROTECTOR AND GARMENT FIELD OF INVENTION This invention relates to body protectors for use in protecting the human body from impact damage. One form of the invention is protective vest 5 for use in sports, particularly equestrian activities such as horse racing or harness racing.

BACKGROUND OF THE INVENTION A number of devices have been suggested and developed for use in protecting the human body from impact damage. One of the earliest devices 10 was the classical suit of armour designed to protect the wearer from blows. Typically such a suit of armour would have rigid outer plates and an inner layer of a cushioning material, such as cloth.

In more recent times body protectors in various forms have been used in contact and non-contact sports to protect against impact related injuries. 15 Furthermore, body protectors in the form energy absorbing pads have been used to protect elderly people against bone fracture injuries resulting from falls.

Some modern body protectors generally use the same fundamental principle as that of the suit of armour.

These protectors for use by players in contact sports such as football or hockey, or for other types of sports with a risk of impact injury baseball will use a rigid outer layer that deflects and absorbs impact forces and inner layer which cushions and provides comfort for the wearer. Examples of such body protectors can found in AU 41918/89 (Sports Protection Limited); AU 25 29095/92 (Marion); AU 58510/94 (685770) (West); AU 72947/87 (590078); EP 564,249 (Sports Protection Limited); US 5,769,688 (Holliday); US 5,245,706 (Moschetti et al); US 4,783,853 (Zuber); US 4,373,211 (Goudreau et al); US 5,020,156 (Neuhalfen); US 5,669,080 (Culton); US 5,325,537 (Marion); US 4,486,901 (Donzis) and US 4,425,667 (Harrison).

Australian patent application no. AU 41918/89 (Sports Protection Limited), as a specific example describes a product which uses a laminate having an outer layer of a high impact strength low or high density polyethylene or polypropylene sheet or skin, a middle layer of high density polyethylene foam and an inner layer of a cross-linked closed cell low density 35 polyethylene or EVA foam. The laminate is said to be useful for body protection for a variety of sporting activities.

However, these types of body protectors typically have the same disadvantages as the classical suit of armour. The protector is relatively heavy <* 2 and often not flexible. This can result in a body protector that has an adverse affect on the performance of the sports person using the protector.

An alternative type of body protector omits the outer layer of a hard sheet or skin, and instead uses other methods to reduce the affects of impact.

These types of body protectors may be particularly appropriate for use in equestrian sports or in protecting the elderly against falling injuries. A number of patent references disclose protectors of this type, and some of these are discussed below.

US 5,465,425 (Cudney et al) discloses a protective vest for use in 10 equestrian sports. The vest utilizes individual ribs of a composite material, said ribs being fitted into skeletal array of pockets. The composite material used is a cross-linked limited high density polyurethane foam laminate having an outer layer of closed cell foam of number 2 denier, an open cell foam core of number 9 denier, an interior layer of closed cell foam of number 11 denier and 15 an innermost layer of a grid or waffling of number 2 denier.

US 5,701,611 (Rector et al) discloses an athletic protective pad comprising a foam composite having an outer layer of closed cell foam, a core layer of open cell foam and an inner layer of closed cell foam. The outer and inner layers are each secured to the middle layer. The outer and inner layers 20 are a polymer foam having major amount of a nitrile rubber, formed from copolymers of butadiene and acrylonitrile, and a minor amount of PVC. The core layer is composed of polyester. The density of the outer foam layer is 6.9 Ib./cubic foot (110 kg/m3), the middle foam layer is 2.5 Ib./cubic foot and inner layer is 6.2 Ib./cubic foot (100 kg/m3).

EP 275,727 (Caoutehoue MFR & Plastiques SA) discloses a composite material for use in protective covers by sportsmen. The material has at least two layers, the external layer being a firm rubber preferably having a hardness of not less than 60 IRMD and a underlying layer of a softer rubber, having a hardness of not more than 50 IRMD. The rubbers used in the composite are 30 processed natural rubbers.

US 5,465,423 (Taylor-Varney) discloses a body-protective vest for use in equestrian sports. It discloses an improved arrangement of impact absorbing foam inserts in a riding vest. The inserts are placed in diagonal orientated pockets in order to allow the vest to fold along stitched crease lines. 35 This arrangement increases wearer comfort as it reduces the likelihood of the vest riding-up the wearer.

DE 3,433,005 (Amer Yhtymae OY) discloses a composite material for use as a protective vest, the composite having at least two layers of foamed / 3 material laminated together.. The patent is focused on reducing the weight of the body protector and reducing production costs. These problems are addressed by forming the body protector in one continuous piece from a laminate of at least two continuous layers of foamed material having different 5 densities. The lighter pillow foam being in the range of 30 to 50 kg/m3 and the heavier pillow foam being in the range of 90 to 180 kg/m3. Pillow foam is typically a latex, polyester or polyurethane foam.

US 4,989,265 (Nipper et al) discloses improvements in the arrangement of foam padding in articles of protective equipment for contact 10 sports. One of the problems faced in using closed cell elastomeric foams is that the foams are not porous and they typically have a smooth outer surface. When such a foam layer is placed in contact with a wearer the layer acts to prevent natural evaporation and traps body heat that results in discomfort for the wearer.

The patent addresses the problem by using a foam layer having a regularly bi-directionally convoluted surface on the side intend to come into contact with the wearer. The convoluted surface enhances circulation of cool air and thus permits evaporation. The document suggests the use of two layers of polymer, wherein the inner layer has a convoluted surface on the 20 wearer facing side and preferably has a slightly lower density than that of an outer, non-convoluted layer. The layers are secured together via fasteners or other means. The foams suggested for use include polypropylene foam of a non-specified density.

AU 19781/97 and AU 67586/98 (The Procter & Gamble Company) 25 each disclose pads for use in protecting the body against impact forces. The pads are primarily for use in protecting elderly people from damage in the hip region caused by falls. The disclosed pads have two layers of foam fixed together. The outer layer is a high density closed cell polyethylene foam and the inner layer is a low density closed cell polyethylene foam. 30 The density of the outer layer is from 128 to 192 kg/m3 and the density of the lower layer is from 48 to 80 kg/m3 for AU 19781/97 and from 32 to 80 kg/m3 for AU 67586/98. The documents suggests that other types of polymers may be used in the foam layers including closed cell polypropylene.

US 4,993,076 (Dierickx) discloses a lightweight, shock absorbing chest 35 protector. The protector is manufactured from two layers of closed cell foam, the outer layer preferably being denser than the inner layer. The protector has a plurality of diamond shaped holes which allows air to circulate. The foam used is a vinylnitrile foam. t 4 US 4,100,620 (Pecoraro) discloses a vest having a semi-rigid closed foamed polyethylene liner in conjunction with a layer of fibrous padding to reduce the impact shock. The layers are located in a cotton or nylon shell.

EP 729,714 (Foam Engineers Limited) discloses a body protection 5 device comprising a outer layer of polyolefin foam and an inner layer of PVC/nitrile foam rubber. The protection device is incorporated into an article of clothing for use motorcycle clothing. The polyolefin layer has a density of from 100 to 300 kg/m3 and the PVC/nitrile layer has a density of from 100 to 250 kg/m3. Polypropylene foam is suggested as being suitable for use as the 10 polyolefin layer.

As can been seen above there have been numerous attempts to provide a body protector which gives sufficient impact resistance whilst being light weight and maintaining flexibility. The protector should not hinder or be cumbersome to the wearer. Other desirable traits include ease of 15 manufacture, use of relatively low cost components and durability in service.

Finally, it is also desirable that the body protector will meet any regulatory requirements setting out required characteristics pertaining to body protector in a particular field. For example, body protectors for use in horse racing activities in Australia.should meet the relevant Australian Racing Board 20 Standard that has minimum impact protection levels.

OBJECTIVES OF INVENTION It is the objective of the present invention to provide a foam construct that will protect against impact damage. It is a further objective of the present invention to provide a lightweight body protector incorporating the foam 25 construct for use in protecting against impact damage.

Preferably the body protector will be more flexible and comfortable to wear than existing protectors and should reduce the hindrance or encumbrance to the wearer.

The protector should also be easy to manufacture, use relatively low 30 cost components and be durable in service.

When the body protector is for use in horse racing activities in Australia the protector should preferably meet the ARB Standard 1 (1998). Likewise when the protector is for use in harness racing activities in Australia the protector should preferably meet the Australian Harness Racing Council 35 Requirements for Drivers Protective Vest, Issue I 1999.

SUMMARY OF INVENTION The present invention relates to a foam construct that will act to protect against impact damage. The invention includes a foam construct that includes * at least a first and a second layer of polypropylene foam in juxtaposition, the density of the first layer being in the range from 55 to 90 kg/m3 and the density of the second layer being in the range from 40 to 65 kg/m3 and wherein the density of the second layer is less than the density of the first layer. Preferably 5 the first layer has a density of about 67 kg/ m3 and the second layer has a density of about 55 kg/ m3.

Preferably the first and second layer are a closed cell polypropylene foam. The construct may also include additional layers of foam. Preferably all of the layers of foam in the construct are also a polypropylene foam, more 10 preferably a closed cell polypropylene foam, and most preferably each of the additional foam layers are have the same characteristics as either of the first or second layers.

It is preferable for the first layer to have a thickness in the range of from 2 to 5.5 mm, more preferably a thickness of about 3.7 mm. It is preferably for 15 the second layer to have a thickness in the range of 2 to 4 mm, and more preferably of about 3 mm.

Another aspect of the invention relates to a body protector in the form of a garment incorporating the above construct. Such a garment would include an inner cloth layer and an outer cloth layer and the construct of the present 20 invention placed between the cloth layers. The inner and outer cloth layers do not need to be made from the same material.

A further aspect of the invention is new positioning arrangement of the construct within the cloth layers of a garment. The new positioning arrangement involves having at least one slit through all of the juxtapositioned 25 foam layers in the construct. The construct is positioned between the cloth inner and outer layers of a garment shell. The construct may be restrained into position by stitching the cloth layers together between the slits, or by other suitable connecting or joining means between the cloth layers. Preferably there are a plurality of transverse slits in the foam layers arranged in a rib-like 30 arrangement.

This arrangement allows the positioning of the foam layers in the garment without the necessity of affixing the individual layers of polypropylene together or to the cloth layers or by the use of pockets in the garment. There are flexibility and cost advantages with this method.

According to a further aspect of the invention is there is provided a * 6 protective garment for use by jockeys engaged in equestrian racing activities. Preferably the protective garment will have a total weight less than 1000 grams, more preferably less than 600 grams. For racing activities it is preferred to use a construct having at least several thin layers of 5 polypropylene foam in juxtaposition, more preferably there are five such thin layers. The use of multiple thin layers of polypropylene foam in the construct is preferred as it provides a more flexible protective garment when the layers are located in a cloth shell by the positioning arrangement described above.

The two innermost layers preferably have the same density and width 10 as each other. The three outermost layers preferably have the same density and width as each other.

Preferably the density of the inner layers is in the range from 40 to 65 kg/m3, and more preferably about 55 kg/m3. The width of each of the inner layers should each be in the range of from about 2 to 4 mm, and more 15 preferably about 3 mm. The density of outer layers should be preferably in the range from about 55 to 90 kg/m3 and more preferably about 67 kg/m3. The width of each the outer layers preferably should be in the range from about 2 to 5.5 mm, and more preferably about 3.7 mm. The density of the outer layers should be greater than the density of the inner layers.

BRIEF DESCRIPTION OF DRAWINGS Fig. 1 is a front perspective view of a garment incorporating the body protector according to an embodiment of the invention.

Fig. 2 is a cross section taken along of the line A-A of Fig. 1.

Fig. 3a is an enlargement of a portion of the cross section shown in Fig. 2.

Fig. 3b is an enlargement of a portion of the cross section shown in Fig. 2. showing a stitched cloth surface layers.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT As shown in figure 1, a impact protecting garment is shown in the form 30 of a vest (1). The garment may of course be made in a variety of shapes depending on the intended field of use.

The vest (1) has two arm cut-away portions (2) and a neck aperture (3). The vest (1) is shown with a crotch strap (4). The crotch strap (4) has an attachment means (not shown) for attaching it to the other side of the vest by 35 any known releasable fastening means, such as Velcro fasteners. The crotch strap is used to prevent the vest from riding up when worn. The crotch strap is merely one form of a retention device and it may be omitted or replaced with leg straps depending on the intended field of use of the garment and on the I 7 garments shape.

The vest (1) has a cloth outer layer (7) covering the foam layer construct beneath. The cloth used may be cotton, nylon or polyester cloth or any other suitable cloth. Preferably the cloth outer layer will be formed from a 5 long wearing fabric in order to form a durable vest. The vest (1) may contain ventilation holes (not shown) in order to vent body heat and improve the wearers comfort.

Figure 2 shows a cut away section of the vest (1) taken along the line A-A, when viewed from the direction of the arrows. An enlargement of the area 10 marked by the circle is shown in Figures 3a and 3b.

Figure 3a shows the cross section of the foam layer construct (5) without the cloth inner and outer layers. Figure 3b shows the cross section of the foam construct (5) with the cloth inner layer (6) and outer layer (7).

The foam layer construct (5) has five layers of closed cell polypropylene 15 foam in juxtaposition. The three outer layers of foam (8), (9) and (10) have the same density and width as each other. The foam layers (8), (9) and (10) have a density and width of 67 kg/m3 and 3.0 mm respectively.

The two inner layers of foam (11) and (12) have the same density and width as each other. The foam layers (11) and (12) have a density and width 20 of 55 kg/m3 and 3.7 mm respectively.

The number of layers, their density and thickness described above is preferred for use in a protective vest for use in equestrian activities. However other arrangements, numbers of layers, their densities and thickness may be used, so long as there are at least two layers of foam having different 25 densities. For example, in this instance the foam layer construct (5) had the same general shape as the vest (1) itself extending into the arm cut-away portions (2) and crotch strap (4) in order to provide a maximum level of protection. In an alternative vest the crotch strap (4) omits the foam construct (5).

It is important to use closed cell polypropylene foam is used in the foam construct as it gives effective impact protection without significantly increasing the weight of the vest. It is also important that the outermost layer of the foam construct has a higher density than that of the innermost layer. During an impact the higher density foam will deform and disperse the energy of the 35 blow over a wider area than that of the contact area of the blow. This results in the inner less dense layers absorbing the energy over a greater area and as such provides a greater cushioning effect.

The use of closed cell foam means that the polypropylene foam will not '4 8 absorb water. If an open, cell foam is used the foam will absorb water becoming wet. After a period of use this will be uncomfortable for the wearer. Furthermore, it may significantly increase the weight of vest and it may have an adverse affect on the impact absorbing capabilities of the vest.

It was also found that it was important to use of polypropylene foam in order for the effective impact protection over a selected temperate range. Surprisingly it was found that other polyolefins, particularly polyethylene foam did not met the required temperature performance criteria. The use of polypropylene foam was also required in order to provide a lightweight foam 10 construct and thus a lightweight garment.

The foam construct (5) has transverse slits (13) therein. The relative location of these slits in the vest are shown by the dashed lines (14) in Figure 1.

These slits are used in conjunction with a cloth fastening means to 15 restrain the foam layers in the vest. The cloth inner layer (6) is fastened to the cloth outer layer (7) across the transverse slit by any suitable means such as stitching or heat welding to form a join (14). The foam layers (8), (9), (10), (11) and (12) are themselves not directly fastened together nor are they are directly fastened to the cloth layers in this embodiment of the invention. The join (14) 20 acts to restrict the movement of the foam layers in the vest.

This arrangement allows the foam layers to move to a limited extent in respect to each other and the clothing layers. As a consequence the vest is more flexible and less encumbering.

However, it is not necessary to always use the above arrangement to 25 restrain the foam layers. Known restraining methods such as forming a multilayer foam laminate, fixing the foam layers to the cloth layers or using pockets in a cloth garment may be used for body protectors which do not need to be as flexible.

This vest was tested to determine its suitability for use in horse racing 30 activities. Same test requirements were used for harness drivers. The Standard used was that set down by the Australian Racing Board -Requirements for riders protective vests, Standard 1 (1998) and Harness Racing Council Standard I 1999.

A test portion of the vest was placed over a domed anvil. A guided flat 35 impactor was dropped onto the test portion. The peak force transmitted through the test portion to the anvil was measured by a piezo electric load cell. * 9 The drop velocity was monitored at the point of impact to within an accuracy of 2.5%. The impactor had a circular flat face 80 mm in diameter and a total mass including the carriage of 5.0 kg. The anvil is 100 mm in diameter with a 150 mm radius of curvature domed top. The test instrumentation 5 complied with the SAE J211 b - Instrumentation for Impact Tests requirements.

Ten tests were carried out with a drop energy of not less than 25J. The tests were carried out on the vest test portion after the vest has been conditioned. The vest was subjected to three different types of conditioning methods Ambient Conditions - the vest was exposed to an air temperature of 20 ±2 jC for at least 4 hours.

High Temperature - the vest was exposed to an air temperature of 40 ±2 jC for at least 4 hours.

Water Immersion - the vest was immersed in water at a temperature from 10 to 30 jC for at least 4 hours.

After each type of conditioning the vest was tested. The average peak transmitted force did not exceed 4.0 kN, with no single test exceeding 6.0 kN. Accordingly the vest passed the impact performance requirements of the Standard.

Claims (21)

WHAT WE CLAIM IS:

1. A foam construct which includes at least a. first and a second layer of polypropylene foam in juxtaposition, the density of-the first layer being in the range from 55 to 90 kg/m3 and the density of the second layer being in the range from 40 to 65 kg/m3 wherein the density of the second layer is less than the density of the first layer.

2. A foam construct as defined in claim 1 wherein the first layer has a density of about 67 kg/ m3 and the second layer has a density of about 55 kg/ m3.

3. A foam construct as defined in claim 1 or 2 wherein the first layer has a thickness in the range of from 2 to 5.5 mm.

4. A foam construct as defined in claim 3 wherein the first layer has a thickness of about 3.7 mm.

5. A foam construct as defined in any one of claims 1 to 4 wherein the second layer has a thickness in the range of 2 to 4 mm.

6. A foam construct as defined in claim 5 wherein the second layer has a thickness of about 3 mm.

7. A foam construct as defined in any one of claims 1 to 6 wherein the polypropylene foam is closed cell polypropylene foam.

8. A foam construct as defined in any one of claims 1 to 7 wherein the construct includes additional layers of foam. 11

A foam construct as defined in claim 8 wherein all layers of foam in the construct are closed cell polypropylene foam.

10. A foam construct as defined in claim 9 wherein each of the additional layers of foam have the density and width of either first or second layer.

11. A foam construct as defined in any one of claims 8 to 10 wherein the construct has five layers of foam in juxtaposition to each other, with each layer in a first group of three layers has a density in the range from 55 to 90 kg/m3 and are disposed together and each layer in a second group of two layers has a density in the range from 40 to 65 kg/m3 and are disposed together, with the first group being disposed adjacent to the second group of layers.

12. A foam construct substantially as hereinbefore described with reference to the figures.

13. A body protector which" incorporates at least one foam construct as defined in any one of claims 1 to 12, the foam construct being so located that the second layer of the construct will be positioned closer to the body to be protected than the first layer of the construct

14. A body protector as defined in claim 13 which further includes two cloth layers, and the construct is located between the cloth layers.

15. A body protector as defined in claim 14 in the form of a garment.

16. A body protector as defined in claim 15 wherein the garment is a protective vest.

17. A body protector substantially as hereinbefore described with reference to the figures. 502867 12

18. A method for positioning and restraining foam constructs, the method including:- providing a foam construct as defined in any one of claims 1 to 11, having at least one slit in the construct, providing a cloth shell including a first and second layer of cloth, locating the construct within the cloth shell between the first and the second layer of cloth, and joining the cloth shelljhrpugh the slit or slits of the foam construct.

19. A method as defined in claim 18 wherein the foam construct includes a plurality of slits.

20. A method as defined in claim 19 wherein the first and second layers of cloth forms part of a vest and the plurality of slits are located in a rib-like arrangement.

21. A method as defined in any one of claims 18 to 20 wherein the foam construct is as defined in any one of claims 1 to 12.