MXPA99008461A - Flexible lightweight protective pad with energy absorbing inserts - Google Patents

Abstract

Disclosed is an improved protective pad for protecting the human body against impact forces. The pad (10) is formed using layers of high density closed-cell polymer foam low density closed-cell polymer foam, and resilient or non-resilient energy absorbing inserts. The high density layer (16) absorbs and shunts impact forces, while the low density layer (18) acts as a cushion against the human body, and provides for comfort. The pad can be provided with a plurality of holes (12) through its thickness to provide for breathability and release of heat from the human body, the surface area of the holes being great enough to allow for adequate ventilation butnot so great as to significantly decrease the protection offered by the pad. The pad can also be provided with a plurality of score lines across its surface and partially through its thickness to provide for flexibility and conformability to the part of the human body being protected. According to the invention, the holes can be provided with at least one resilient energy absorbing insert.

Description

FLEXIBLE PROTECTIVE PAD WITH LIGHT WEIGHT WITH INSERTS THAT ABSORB ENERGY FIELD OF THE INVENTION The present invention relates to protective padding for the human body. The present invention further relates to said protective pads which are light in weight, impact absorbers, flexible, and with ventilation capacity.

BACKGROUND OF THE INVENTION Hip pads, and other protective padding, have been used to protect the human body from damage caused by impacts due to falls, accidents, sports, and other related events. In particular, the fracture of a bone as a result of an accidental fall is a common event in the elderly, in people who have osteoporosis and in people whose standing position is wobbly and have difficulty walking. In the elderly, especially those with osteoporosis, bone fractures are very difficult to treat and it is highly desirable in the first instance to prevent them from happening.

A wide variety of pads and protective garments have been available in the past, but all of them with some drawbacks. A typical garment of protective clothing is a pad that is permanently attached to a garment, or that slips in a pocket in the garment, or is held in place by means of tapes or an adhesive that does not affect the skin, so that the pad is placed over an area of the body prone to injury. This area prone to injury, especially in the elderly, is the area of the hip. Hip fracture, which occurs in 2% to 3% of cases, especially in elderly people who fall frequently, usually involves fracture of the proximal end of the femur. This part of the femur consists of a head, a neck, a greater trochanter and a lower trochanter. The greater trochanter projects outward toward the distant lateral area of the hip region and, because it is located in this way, is subject to an impact force on the hip arising from a fall, in particular from falls in the street. To protect the hip area, the pads are typically attached to the inside of the clothing in the area that covers the hips, or are placed in pockets made on clothing at the hip area. More specifically, the pads are typically placed in such a way as to cover the greater trochanter, or in the case of certain types of pads that deflect force or energy, they surround the greater trochanter without truly covering it.

The degree to which a pad needs to attenuate the impact force during a fall is subject to numerous debates. This is because the measures of the force needed to fracture the corpse femurs of elderly people in simulated load-bearing configurations vary widely. These measurements vary from 2110 Newtons (JC Lotz &WC Hayes, J. Bone Joint Surg. [Am], Vol. 72, pp 689-700, 1990) to 6020 Newtons (TG Weber, KH Yang, R. Woo, RH Fitzgerald, ASME Adv. Bioeng, BED22: pp 1 11-1 14, 1992) depending on the load ratio. In addition, the speed at which the torso of a human falling and hitting a hard surface such as a tile floor can vary between 2.0 to 4.5 meters / second. Researchers (S. Robinovitch, J. Biomech, Eng. Vol. 9, pp. 1391-1396, 1994, have cited average speeds of approximately 2.6 meters / second); They have measured the speed of human volunteers who drop on their hips. The estimated amounts of force applied to the greater trochanter not covered with pads during a fall also vary widely from 5700 Newtons to 10,400 Newtons (J. Parkkari et al., J. Bone and Mineral Res., Vol. 10, No. 10 , pp 1437-1442, 1995). The best evidence of the effectiveness of a pad is obtained from clinical studies conducted in living humans. This study has been carried out by Lauritzen and others, (Lancet, Vol. 341, pp 11-13 1993) using a rigid shell-type pad. It was found that this pad reduces the incidence of hip fractures by approximately 50% in the population studied. Due to these convincing clinical results, the Lauritzen pad has been shown to provide relatively low strength attenuation results when placed on an artificial hip and impacted with a heavy pendulum (35 kilograms) that moved at a speed of 2.6 m / sec. (S.N. Robinovitch, et al., J. Biomechanical Engineering, Vol. 1 17, pp 409-413, 1995). Under these in vitro test conditions, the Lauritzen pad reduced the maximum femoral force from about 5770 Newtons to about 4800 Newtons, to only about 17%. A protective hip product based on the Lauritzen pad has been marketed in Denmark by Sahvatex (a joint venture between Sahva A / S and Tytex A / S) under the trade name of SAFEHIP ™. The hip protectors, which are oval-shaped structures, contain rigid plastic shells and are sewn into cotton underwear. These clinical findings suggest two hypotheses. First, that the pendulum impact tests used by other researchers can not correlate well with the performance of the pad in vivo even though such tests may be useful for measuring the force reduction capabilities of several pad systems in relation to the pads. the rest. In such tests, the pad is placed on an artificial hip that is held in a fixed position and tapped laterally with an oscillating mass weighing approximately 35 kilograms or more. In a true fall, the dynamics are somehow different. In a fall, both the pad and the mass of the human body move down, and in fact they accelerate downward due to gravity, and hit a fixed object such as the ground or a rigid surface that does not have much movement in response . It could be assumed that if an artificial hip made with instruments fell on a hard surface, in order to better imitate the dynamics of a fall, the disposition category of several padding systems would probably be similar, but in some way different results would be obtained. percentage of force reduction. The second hypothesis assumes that the pendulum test does not correlate with the performance of the pillow? N vivo, and that even the pads that provide relatively low levels of maximal force reduction in vitro (approximately 20% or more) can be effective for reduce hip fractures on a population segment of elderly people prone to falls. In either case and without considering the test method, a pad that reduces maximum force more than the clinically proven Lauritzen / Sahvatex pad can be more effective in preventing hip fracture and protecting an even larger segment of the population. of elderly people. Obviously, the more force reduction obtained in a pad, the more likely it is to reduce the incidence to hip fracture. However, the study conducted to consumers has shown that, in addition to reducing the impact force exerted on the greater trochanter during a fall, the pads must also provide other benefits to reinforce the needs of the user. These relate to both appearance and comfort of the user and include attributes such as maximum thickness, thickness profile, weight, ventilation capacity, flexibility, and adaptability to the body. The previous pads have had many drawbacks in these aspects. Some cushions of previous techniques have been bulky and uncomfortable in an attempt to provide adequate protection against impact; Many pads typical of previous techniques attempted to provide effective impact strength greater than 25.4 mm (one inch) in thickness. The thin pads of the prior techniques typically provide low impact resistance, were characterized by providing less than a 30% reduction in maximum force as measured by artificial hips that were dropped or hit with heavy pendulums. Other pads have not counted on the ventilation capacity, which results in an accumulation of heat in the skin covered by the pad. Still, there are other cushions that have been hard and rigid, so they do not adapt to the covered parts of the body. In addition, hard shell-like pads tend to be uncomfortable when sitting or when sleeping. The soft foam pads require a greater thickness to absorb the forces of impacts, with a greater thickness it results in a more bulky, less comfortable pad and increases the heat accumulation under the pad. All have resulted in relative discomfort for users.

Research conducted with consumers has shown that potential users, regardless of age or physical condition, care about their appearance. Preferred hip pads should not be greater in thickness of 25.4 mm, and most preferred are those of 19 mm maximum in thickness or less. The thickness dimension is also important. Preferred pads are those that are tapered from the area of maximum thickness to perimeter such that neither the pad nor the edges of the pad can be displayed under normal clothing. A perimeter thickness scale around the pad of 12.77 mm or less is generally preferred. A perimeter thickness scale of 6.35 mm or less is further preferred. And a perimeter thickness scale of 3.18 mm or less is still more preferred. The weight of the pad is a matter of interest, since most of the potential users are elderly women with tendencies to the lean body and reduced muscle mass. The preferred pads consist of approximately 300 grams each (600 grams per pair). And even more preferred are the pads whose weight is less than 200 grams each (400 grams per pair). And even more preferred are pads weighing less than about 100 grams each (200 grams per pair). Unlike sports pads whose purpose is to be used for short periods, protective hip pads for the elderly are designed to be worn all day, whether inside or outside the home, in all climates and Be hot or cold and under any humidity condition. The typical foam pads are made of closed cell foams that do not pierce the body's moisture or perspiration. In addition, said pads are thermal insulators and do not effectively dissipate body heat. This leads to increased perspiration and moisture accumulation under the pad, which can damage the skin of elderly users. Therefore, the preferred pads have a substantially open area, preferably at least 5% or more, and most preferably about 10% or more, to allow the evaporation of perspiration and to ventilate body heat. A new improved protective padding is described herein, which provides increased impact resistance in a relatively thin and light weight pad. The increased resistance to impact is maintained while providing ventilation capacity to prevent heat buildup and associated discomfort. In addition, this new pad provides flexibility and adaptation to the part of the human body that is to be protected, without any adverse impact on its protective qualities.

BRIEF DESCRIPTION OF THE INVENTION In accordance with the present invention, a protective pad is provided to protect a previously defined area of the human body from impacts, the pad has a surface and a thickness, the pad consists of a layer of closed cell high density polymer foam the outer surface of the pad that is away from the wearer's body, and a layer of low density closed cell polymer foam on the inner surface of the pad, which remains in contact with the wearer's body. Typically, the high density foam has a density of about 128 to about 192 kg per cubic meter and preferably about 160 kg. per cubic meter. The high density foam typically has a Shore 00 durometer hardness of about 72 to about 95. The low density foam typically has a density of about 32 to about 80 kg. per cubic meter, and preferably 64 kg. per cubic meter. The low density foam typically has a Shore 00 durometer hardness of around 40 to about 70. The layers they are fixed together to provide a lightweight pad that provides relatively high resistance to impact forces and a relative comfort for the user. The pads of the present invention have one or more cavities to accept additional energy absorbing materials in the form of pins or inserts. These cavities can be cut inside the pad from the outside of the pad by extending a portion of the distance through the pad, or located inside the internal structure of the pad and covered by the inner and outer layers of foam. These cavities are generally located in or around the central area of the pad. The additional energy absorbing insert material or materials are selected to have a lower hardness, or lower stiffness, or lower compressive strength, or higher damping than high density foam. In this aspect, damping refers to the ability of the material to dissipate the energy of the impact internally, where most of the energy used to deform the material dissipates directly in heat. The additional energy-absorbing insertion material or materials are selected from those groups consisting of polyolefins or other polymeric foams, elastic rubber foams, high-damping elastomers, high-damping polyurethane compositions, polyurethane healing gels, plastisol gels of polyvinyl chloride, viscoelastic foams and related materials. By including said additional energy absorbing materials a pad is achieved which can generally be reused after multiple impacts. In accordance with the present invention, single-use disposable pads can also be constructed. In such cases the cavity or cavities are filled with a crushable, non-elastic material such as an expanded polystyrene foam or other plastic foam that is irreversibly crushable under the impact force of a fall. The pad may have a plurality of reference lines across the outer surface and partially through the thickness to provide substantial flexibility and adaptation to the area of the human body covered by the pad, without significantly affecting the resistance to impact forces. The reference lines may pass through the insertion material or materials or may be placed in such a manner that they do not traverse the insertion material or materials. The pad may also have a plurality of open areas on the surface and completely through the thickness to provide the ventilation and heat dissipation capacity of the human body area covered by the pad, while maintaining significant resistance to impact forces. In general, the pad weighs less than about 100 grams and has a preferred maximum thickness less than about 25.4 mm. The total size of the pad or area covered by the pad can vary from about 96.7 to about 387.0 square cm. The percentage of the open area can vary from about 5% to about 50% depending on the total size of the pad. In general, the percentage of the open area of the pad is selected such that it provides maximum ventilation while still providing approximately 40% or more of maximum force reduction as measured in a fall impact test on an artificial hip. The preferred pads of the present invention meet or exceed the goal of maximum force reduction of 40% at a pad weight of 100 grams or less; a minimum force reduction of 40% is key to the present invention. Therefore, the ratio of the maximum force reduction percentage, as measured in an artificial hip fall impact test, to the weight of the pad in grams is approximately 0.4 percent per gram. Very preferred are pads that meet or exceed 40% of the target at pad weights of 50 grams or less, thus providing at least 0.8% strength / gram reduction. And still very preferred are the pads that meet 40% of the target to the pad weights of 30 grams or less thus providing at least 1.33% strength / gram reduction. In general, the preferred scale of the percentage force reduction ratio per gram of pad weight is about 0.25 percent per gram to about 8.00 percent per gram. This ratio is most preferably about 0.40 percent per gram to about 6.00 percent per gram. Said pads can be fixed to a garment permanently or removably. The garments are preferably made of fabric that promotes by capillarity the accumulation of perspiration outside the human body.

BRIEF DESCRIPTION OF THE DRAWINGS Although the detailed description concludes with claims that particularly designate and distinctly claim the present invention, it is believed that it can be better understood from the following description along with the accompanying drawings, in which: Figure 1 is a plan view of a protective pad of the present invention. Figure 2 is a partial cross-sectional view through lines 2-2 of Figure 1. Figure 3 is a plan view of an alternative embodiment of a protective pad of the present invention. Figure 4 is a perspective view of the hip pad of Figure 1 showing the pad in a flexed position. Figure 5 is a plan view of another alternative embodiment of a protective pad of the present invention. Figure 6 is a partial cross-sectional view through lines 6-6 of Figure 5. Figure 7 is a plan view of another alternative embodiment of a protective pad of the present invention in which the insert is completely encapsulated by layers of high density and low density foam.

Figure 8 is a partial cross-sectional view through lines 8-8 of Figure 7.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the detailed drawings where the same element is indicated with numbers in the different perspectives, an embodiment of the present invention of the protective pad 10 is shown in Figure 1. The protective pad 10 is relatively light in weight and it is relatively thin (less than 25 mm in thickness, but most preferably 19 mm or less). It can also be relatively flexible and its contour as required depending on its specific use, as will be described in greater detail later herein. The pad 10 has a wide open area in its thickness for ventilation capacity, while maintaining significant impact resistance, as shown by the holes 12. The present pad 10 also effectively reduces the strength of the pad. an impact at least 40% compared to the impact force experienced without protection, as measured with an artificial hip drop tester made with instruments. Figure 1 further shows the placement of an energy absorbing insert, segmented by the reference lines 14 in the four sections A, B, C and D, forming a square-shaped insert located in the center of the pad. In addition to having a square shape, the shape of the insert can be circular, oval, rectangular, triangular, pentagonal, hexagonal or any other shape. The high density layer 16 forms the outer surface of the pad, and the low density layer 18 forms the inner surface of the pad. The pad 10 can be made in a variety of shapes based on the particular style desired and its application, such as rectangular (as shown in figure 3), square, round, oval and the like. The multiple inserts E, F, G and H are shown located near the center of the pad; those skilled in the art will be able to glimpse a variety of different positions and configurations for these inserts. In Figure 3, the holes 12 provide Sa ventilation capacity and the reference lines 14 provide flexibility and adaptation to the protected area of the human body. The holes 12, for the capacity of ventilation and heat dissipation of the body under the pad, can vary from about 3.18 mm to about 25.4 mm in diameter depending on the desired levels of ventilation and impact resistance. Other holes such as oval, square and the like can also be used. The area of the surface dedicated to the holes 12 should be wide enough to provide sufficient ventilation, but not so wide as to decrease the reduction of maximum force and the capacity of the pad 10 less than 40%; the area dedicated to the holes 12 can vary from 5 to 50 percent of the total surface area to maintain at the same time significant resistance to impact. The pad 10 can be divided into a lattice shape by partially splitting through its thickness, producing reference lines 14. The reference lines 14 are preferably cut from a depth of about 1/4 to 3/4 of the total thickness of the pad , and through the surface area, as shown in Figures 1 and 3. The reference lines 14 are cut or molded into the pad from the outer surface or from the high density foam side of the pad. This makes the pad very flexible and capable of adapting to a wide range of shapes and sizes. The flexibility for the reference lines 14 is shown in Figure 4. The pattern and spacing for applying the reference lines may vary. For illustrative purposes, Figures 1, 3 and 4 show the reference lines cut at + or - 45 ° from the straight edges of the pads and passing through the centers of the holes in the pads. The reference lines can also be cut 90 ° from the straight edges of the pad or at any angle between + and - 45 ° and 90 ° from the edges. The reference lines can pass through the holes, between the holes, or in combinations through and between the holes. The reference lines do not need to be cut in straight lines parallel and perpendicular to the others as shown in figures 1, 3 and 4. They can also be cut in a fan-shaped arrangement on one side of the pad. They can be cut in a curve, in a sinusoidal way, or in a zig-zag shape crossing the pad. The preferred separation between the reference lines is between 6.53 mm and about 50.8 mm. The most preferred spacing between the reference lines is between 12.77 mm and about 25.4 mm. Figure 5 shows still another embodiment of the present invention, in this case a pad containing a single circular insertion accessory "J" and without reference lines. The pad is made with at least two different types of foam materials plus one or more insert materials placed in the cavity or cavities of the pad. The outer impact layer 16 is a rigid high density material, preferably a closed cell polymer foam, for example Voltek L1000 polyethylene foam (Voltek, Lawrence, Massachusetts 01843). According to the manufacturer, this material has an approximate density of 160 kg / m3 (10 pounds / cubic foot), a hardness Shore 00 of about 75, a force at compression of about 4.49 kg / cm2 to a deformation of 25%, and a compressive strength of about 6.8 kg / cm2 at a 50% deformation. The inner layer 18 is a soft low density cushion material, also preferably a closed cell polymer foam, for example the Sentinel MC3800 polyethylene foam (Sentinel Products Corporation, Hyannis, Massachusetts 02601). According to the manufacturer, the MC3800 foam has a density of about 64 kg / m3, a Shore 00 durometer hardness of about 70.5, a compressive strength of about 1.75 kg / cm2 at a 25% strain, and a compressive strength of around 3.0 kg / cm2 at a 50% deformation. The outer layer 16 absorbs the force of the impact via compression and diverts the force of the impact to the perimeter of the pad and is rigid enough to prevent the pad from being crushed by impact, while the inner layer 18 provides the comfort and degree of flexibility needed to adapt to different parts of the human body. The final result is a combination of high strength, effectiveness and comfort reduction. The sheet of the pad 10 can be manufactured by dividing the two layers together into sheets and giving them shape by mechanically grinding, or using mold rollers and a profiled turning blade. Alternatively, the pad can be manufactured by heating the two layers and compressing them at the same time under heat and pressure. Such manufacturing methods are known to those skilled in the art. The foam layers are from closed cell foams, preferably closed cell polyolefin foams, but other materials having similar properties can also be used. Closed cell foams of suitable polyolefins are derived from low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), ethylene acetate copolymer- vinyl (EVA), ethylene methylacrylate (EMA) copolymers, ethylene ionomers, polypropylene and polypropylene copolymers. These polyolefin materials are preferred because they do not absorb water or sweat, nor maintain microbial growth and generally do not irritate and do not cause sensitization of human skin. Other suitable materials may include rubber foams derived from natural rubber, butyl rubber, polyisoprene, polybutadiene, polymorphone, styrene-butadiene, neoprene, acrylonitrile rubber, and other related rubber materials, polyurethane foams, and polyurethane foams. plasticized polyvinyl chloride (PVC). Although other materials, such as polyurethanes or rubber foams, can act at desirable levels of impact resistance, care must be taken to select such materials for the pads to be used in direct or indirect contact with human skin. Those skilled in the art can formulate special grades of each, to inhibit the absorbency of water or sweat, to prevent microbial growth and to prevent skin irritation and sensitization, characteristics that may cause discomfort of the user or may result to the detriment of the user's health. The outer layer 16 has a density of about 128 to about 192 kg / m 3 with about 160 kg / m 3 which is the preferred density; the inner layer 18 has a density of about 32 to about 80 kg / m 3 with about 64 kg / m 3 which is the preferred density. Preferred values result in a combination of significant comfort and impact resistance in a single pad. Additionally, providing a high or outer high density layer with a thickness of at least 50% of the total thickness of the pad maximizes the performance of the pad.

The additional energy absorbing material that is placed in the cavities in the pad structure can be selected from different materials, including (1) polyolefins or other plastic foams, (2) elastic rubber foams, (3) foams high damping, (4) high-buffered polyurethane compositions, (5) curative polyurethane gels, (6) high-cushion polyvinyl chloride plastisol gels, (7) viscoelastic foams, or (8) elastic thermoplastic laminates. (1) Preferred polyolefins or other plastic foams are closed cell foams, selected from the group including low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene. (HDPE), ethylene-vinyl acetate (EVA) copolymers, ethylene-methyl acrylate copolymers (EMA), ethylene, polypropylene and polypropylene copolymers. These polyolefin materials are preferred because they do not absorb water or sweat, do not maintain microbial growth, and generally do not cause irritation or sensitization on human skin. It is generally preferred that the hardness or compressive strength of polyolefins or other plastic foam inserts or inserts be less than those of the outer layer of high density foam of the pad, preferably less than about 72 as measured according to the Shore 00 durometer scale. (2) Elastic foamed rubber inserts may be derived from natural rubber, butyl rubber, polyisoprene, polybutadiene, polynomorbent, styrene-butadiene, neoprene, acrylonitrile rubber, and related rubber materials, such as polyurethane foams and chloride foams plasticized polyvinyl (PVC). If the elastic foamed rubber insert is exposed to the outside of the pad, it is generally preferred that a closed cell foam is selected to prevent absorption of water during the washing process. It is generally preferred that the hardness of the foamed rubber inserts be less than the hardness of the outer layer of high density foam pad, preferably less than about 72 as measured on the Shore 00 durometer scale. (3) High-cushion rubbers include those families of solid rubber materials characterized by including high fillers of oils, plasticizers and fillers such as carbon black. The rubber itself can be based on synthetic or natural polyisopropene, polybutadiene, butyl rubber, polynomorbent, ethylene-propylene diene monomer rubber (EPDM), styrene-butadiene rubber, and other rubber known to those skilled in the art of formulating rubber. The high damping properties are generally conferred through the incorporation of high levels of oils, plasticizers, and fillers such as carbon black. The formulation of high-buffering rubbers based on polynorbornene is described in "A New Synthetic Rubber Norsorex® Polynorbomene" presented by R.F. Ohm and T.M. Vial at the Hules Division conference, American Chemical Society, Cleveland, Ohio, October 4-7, 1977) and "Polynorbornene: The Porous Polymer" (RF Ohm, Chemtec, March, 1980) both incorporated herein by reference only . Those formulations that show high damping to the force of impact at room temperature and at deformation frequencies comparable to those experienced in the fall in the soil of a human, are preferred. Examples of such polyborbornne and butyl rubber derived materials can be obtained from Rubber Associates, Inc. (Barberton, Ohio 44203) in Shore A hardness scales from 70 to about 30. Preferred for the current invention are high cushion rubbers. which have a Shore A hardness of 50 or less. Even more preferred are high cushion rubbers having a Shore A hardness of about 40 or less. (4) High-buffered polyurethane compositions are formed by the reaction of substantially linear polyols, slightly branched, having final hydroxyl groups and a number of average molecular weights in the range of 600 to 1200 grams per mole with an aromatic diisocyanate in smaller amount than the stoichiometric amount. Compositions of this type are described in the patent of E.U.A. 4,346,205 incorporated herein by reference. Similar materials are commercially available under the trade name Sorbothane® at Sorbothane, Inc. (Kent, Ohio 44240). Although it is a solid, Sorbothane® offers almost liquid properties that allow to exhibit high energy absorption and high mechanical damping. It is available in a hardness that varies from 70 on the Durometer scale from Shore 00 to approximately 30. The Sorbothane® itself can function as an effective cushion to reduce the force of impact on the body, but its high density of around 1280 kilograms per cubic meter creates a very heavy pad that could be inconvenient to use. By using Sorbothane®, as well as high-buffered polyurethane compositions as an insert or insert within the lightweight foam laminate of the present invention, high mechanical damping can be obtained while maintaining a weight pad relatively light (5) The curative polyurethane gels are often used to duplicate the properties of human tissue and skin. They have excellent energy and elasticity damping properties. A family of curative polyurethane gels is derived from 3 component systems of liquid materials constituting an "A" component described as a solution of glycol terminated with aromatic diisocyanate, a component "B" described as a solution of polybutadiene polyol, and a component plasticizer "C" described as a mixture of dialkyl carboxylates and alkyl. A typical formulation is made from 50 parts by weight of component "A", 100 parts by weight of component "B" and from zero to 200% by weight of the total of mixture A / B. These gels are manufactured by BJB Enterprises, Inc. (Garden Grove, California 92643) under the trade name Flabbercast ™. Many families of curative polyurethane gels can be derived from 3 different systems of liquid components. An example is Skinflex lll ™, which is also available from BJB Enterprises. In Skinflex III ™, component "A" is described as a mixture of polyoxypropylene glycol terminated with aromatic diisocyanate, component "B" is described as a polyol diamine mixture, and plasticizer component "C" is described as a dialkylcarboxylate. The ratio of the mixture is 50 parts of "A" and 100 parts of "B" in weight while the plasticizer "C" can vary from zero to 50% of the total weight of "A" and "B". The curative polyurethane gels have relatively high densities and the pad inserts made therefrom can be weighed and add weight to the pad. It is possible to decrease the weight of the inserts by up to 50% or more by adding organic and inorganic hollow fillers, for example hollow glass microspheres, to the gel before it is cured. Scotchlite ™ glass beads (3M Co., St. Paul, Minnesota 55144) are examples of suitable light weight fillers. Since it is possible for the plasticizer to migrate to the curative polyurethane gel, it is generally preferred to completely encapsulate the gel insert between the low density and high density foam layers as shown in Figure 8. (6) Plastisol polyvinyl chloride (PVC) high buffer are prepared from a larger portion of plasticizer and a smaller portion of PVC resin. Said plastisols are dispersions of PVC resins of special fine particle size dispersed in plasticizing liquids. Additional components may also be included, such as thermal stabilizers, colorants and other additives known to those skilled in the art of plastisols. In general, a plastisol is liquid at room temperature. When heated to a suitably high temperature, melting occurs by converting the plastisol into a homogeneous viscous mass with excellent impact resistance. An example of said material and its application in a shock-resistant bicycle seat is described in the U.S. patent. 5,252,373 incorporated herein by reference. A suitable plastisol is the "Plastomeric Plastisol MI430 Clear base" and a suitable plasticizer is the "Plastomeric Type B Plasticizer". Both products are available from Plastomeric, Inc. Waukesha, Wisconsin according to which, the liquid base M1430 contains 53% PVC copolymer resin, 27% di-octyl terephthalate, 2.5% soybean oil epoxy, 3% calcium-zinc stabilizers, 7% thixotropic based on PVC, and 7.5% trixotrope based on adipate plasticizer. The melt temperature scale of said plastisols lies between 135 ° C and 204.4 ° C (which may be above the smoothing points of the preferred polyolefin foams used in the laminated pad of this invention.) Instead of fusing the plastisol liquid inside the cavity or cavities of the pad, it may be necessary to cast the liquid plastisol in a suitable metal or plastic mold, heat it to the melting temperature where it fuses into a gel and then insert the rigid rubber product into the cavity or cavities of the pad Since it is possible for the plasticizer to migrate to the fused gel, it is generally preferred to completely encapsulate the gel insert between the layers of low density and high density foam as shown in Fig. 8. PVC plastisol gels with relatively high densities and pad inserts made from them can be heavy and can add weight to the pad It is possible to reduce the weight of the inserts by up to 50% or more by adding organic and inorganic hollow fillers, for example hollow glass microspheres, to the gel before it is cured. Scotchlite ™ glass beads (3M Co., St. Paul, Minnesota) are examples of suitable light weight fillers. (7) Viscoelastic foams are open-cell polyurethane-based materials that offer high-shock and high-impact properties and the ability to absorb shock. The high damping produced in these materials makes the response of the foams to mechanical stress highly sensitive to the range of deformation. At reduced load ratios, the foams deform slowly acting very similarly as a highly viscous fluid. At high rates of deformation, as in the case of an impact, the foams act as much more rigid materials. Examples of such materials include the CONFOR ™ family of viscoelastic foams available from AeroE.A.R. Specialty Composites (Indianapolis, Indiana 46268). These foams have densities ranging from about 92.8 to about 102.4 kilograms per cubic meter and with a Shore 00 hardness at room temperature of about 20 or less. Although viscoelastic foams by themselves can act as absorbing pads effective blows, are open cell. This structure of open cells will cause them to absorb large amounts of water if they are washed, which makes it very difficult to dry them afterwards. For the pads of the present invention, it is preferable to completely encapsulate the viscoelastic foam insert between the low density and high density closed cell foam layers as shown in Figure 8. The preferred thickness scale of the viscoelastic foam insert is from about 6.35 mm to about 19.0 mm. (8) Elastic thermoplastic honeycomb laminates consist of a thermoplastic honeycomb material laminated between two plastic films through the use of heat, adhesives or both. Examples of such honeycomb materials are available from Hexcel Corporation (Pleasanton, California 94588) under the trademarks of Cecore ™ polypropylene and alveolar thermoplastic polyester, Cecore ™ Cush 'n alveolar thermoplastic polypropylene and thermoplastic polyurethane TPU ™ sandwich honeycomb thermoplastic polyurethane. The TPU ™ thermoplastic polyurethane honeycomb sandwich has a cell size of 6.35 mm and is available with film coatings ranging in thickness from about 0.27 mm to 0.508 mm. For the pads of the present invention, the honeycomb sandwich used as the energy absorbing insert may consist of a layer about 12.7 mm thick or two layers each 6.35 mm thick. The comfort of using hip pads can be improved with the design of the garment. The fabric of the garment can improve the ventilation capacity, particularly when combined with a pad with openings for air flow. Fabrics that promote by capillarity the passage of natural moisture outside the skin, promote the regulation of temperature and comfort. "Cottonwick", manufactured by Colville Inc. of Winston Salem, North Carolina, is a particularly effective fabric for this purpose. It has a single-point handle with a polymerized silicone coating that wicks away moisture into the fabric. The knitted handle forms cone-shaped capillaries and the silicone coating directs moisture away from the surface of the fabric towards the cones. The pads of the present invention can be fixed permanently to the garment, for example, by sewing them into the pockets in such a way that the pads can not be removed. The pads that are used in said garments therefore need to be at least hand washable together with the garment, and preferably machine washable. After washing, clothes and pads should be dried. Both procedures, both drying in line at room temperature and machine drying with hot air are facilitated by the open areas in the pads that promote air flow through the fabric of the garment and the pads. Alternatively, the garment may have pockets that can be opened and closed by means of closures, snaps, hook or wool fasteners and the like. This allows the pads to be removed from the garment so that the garment can be washed separately if desired. The following examples are illustrative of the invention but not limiting thereof: EXAMPLE 1 Foam laminate pad machined with cavity but without insert A multi-layer pad is constructed by first cutting a piece of polyethylene foam MC3800 (Sentinel Products Corporation, Hyannis, Mass., 02601) at a density of 64 kg per cubic meter of a sheet of 6.35 mm thick. such that the piece has two straight sides opposite one another and parallel to each other and two curved sides opposite each other as shown in figure 7. They are cut in cube shape at the same time 8 holes of 12.7 mm in diameter spaced around the piece. The distance between the straight sides is approximately 127 mm and the distance between the curved sides measured across the center of the piece is approximately 139.7 mm. This first piece is the side of the skin or the user's side on the pad. A second piece of foam, circular in shape and approximately 1 14.3 mm in diameter approximately 12.7 mm thick, is cut in cube form from the Minicell L1000 polyethylene foam (Voltek, Lawrence, Massachusetts 01843) with a density of approximately 72.64 kg per cubic meter. This piece also has 8 holes of 12.7 mm diameter cut into a cube shape at the same time and with the same space arrangement as the first piece of foam. A much larger, cube-shaped hole, approximately 76.2 mm in diameter and placed with its center coinciding with the center of the piece, is also cut at the same time. This second piece is the outer side of the pad away from the user's body. The two pieces of foam are laminated with adhesive tape on both sides 3M # 343 (3M Co., St. Paul Minnesota 55144) so that the eight 12.7mm holes of each piece are aligned with each other. Subsequently, the laminated assembly is mechanically turned using a cup-shaped lathe wheel to provide the sides slightly tapered to the pad in all directions and to give the laminate a curved or domed cross-section with the L1000 foam placed at most extreme or convex side of the pad. The finished pad weighs approximately 12 grams. This allows a laminated pad to have a cavity of approximately 76.4 mm in diameter and approximately 12.7 mm in depth located in the center of the pad. The high density foam completely surrounds the cavity while the low density foam forms the bottom of the cavity. The maximum thickness is approximately 19 mm in the areas of the pad immediately adjacent to the cavity approximately 3.18 mm or less around the perimeter of the pad. The cushion's ability to cushion against impact against a hard surface is measured on an artificial hip, constructed with polyolefin and closed cell neoprene foams as well as with other components and designed to mimic both the soft tissue response and the response pelvic from a hip of a human in a fall. The artificial hip is dropped at a distance of approximately 37.5 cm in such a way that its impact velocity with a horizontal steel plate is approximately 2.7 meters per second. The artificial hip weighs approximately 35 kg and has an artificial femur and an artificial greater trochanter. A load cell of 2270 kg (Product No. 8496-01, GRC Instruments, Santa Barbara, California) measures the force transmitted to the artificial greater trochanter when the artificial hip is dropped on the steel plate. The force measured in the artificial trochanter when the artificial hip without pad protection is dropped and struck against the steel plate is approximately 6000 Newtons.

For comparison with the pads of this invention, the hip protector of a SAFEHIP ™ product (Sahvatex, Denmark) is removed, and placed on the artificial hip and held in place over the area of the artificial greater trochanter by means of a elastic fabric that covers the outer skin of the hip. When the cushioned artificial hip is dropped and struck against the steel plate at 2.7 meters / second, the maximum force that is measured in the artificial trochanter is approximately 30% less than that measured with the unprotected artificial hip. The SAFEHIP ™ pad weighs approximately 31 grams, which makes the force reduction percentage per gram in weight of the pad approximately 1 percent / gram. However, this level of reduction • Strength is below the minimum of the 40% strength reduction objective of the pads of the present invention. The pad of this example is placed on the artificial hip and held in place over the area of the artificial greater trochanter by means of an elastic fabric covering the outer skin of the hip. The cavity of the pad is centered on the artificial greater trochanter. When the cushioned artificial hip is dropped and struck against the steel plate at 2.7 meters per second, the maximum force measured in the artificial trochanter is approximately 67% less than that measured with the artificial hip without cushioning. The reduction in force per gram of the weight of the pad is therefore approximately 5.58% / gram.

The pad in this example deflects most of the impact force to the areas surrounding the artificial trochanter. The high density rigid foam that surrounds the cavity prevents the pad from collapsing and also prevents artificial skin and artificial soft tissues covering the trochanter from contacting directly with the steel plate during impact. However, when a pad of this construction is placed in the pockets of an undergarment and worn by a person under normal clothing, the outline of the cavity is easily visible, which creates a strongly negative impression of the pad product. /garment EXAMPLE 2 Foam laminate pad with polyolefin foam insert A pad identical to that described in example 1 is constructed in the same way. In a cavity of 76.4 mm in diameter and approximately 12.7 mm in depth located in the center of the pad, a piece of low density polyethylene foam is attached. (6.08 kg / m3) Plastazote® LD60 (Zotefoams, Inc., Hackettstown, New Jersey 07840) in addition approximately 76.4 mm in diameter and approximately 12.7 mm in thickness, by means of the same tape with adhesive on both sides 3M # 343 ( 3M Co., St. Paul, Minnesota 55144) used to laminate the foam layers. The finished pad weighs approximately 14 grams. When evaluated in the artificial hip drop tester, with the insert centered on the artificial trochanter, the maximum force measured on the artificial trochanter is approximately 66% less than that measured on the non-cushioned artificial hip. Accordingly, the force reduction per gram of the pad is approximately 4.71% / gram.

EXAMPLE 3 Foam laminate pad with Sorbothane® insert A pad identical to that described in example 1 is constructed. In a cavity of 76.4 mm in diameter and approximately 12.7 mm in depth located in the center of the pad, a piece of Sorbothane® of hardness 50 of Shore 00 is attached ( from Sorbothane, Inc., Kent, Ohio 44240) of high-cushion polyurethane, in addition to approximately 76.4 mm in diameter and approximately 12.7 mm in thickness, by means of the same tape with adhesive on both sides 3M # 343 (3M Co., St. Paul, Minnesota 55144) used to laminate the foam layers. The finished pad weighs approximately 95 grams. When evaluated in the artificial hip fall tester, with the insert centered on the artificial trochanter, the maximum force measured in the artificial trochanter is approximately 57% lower than that measured in the artificial non-cushioned hip. The reduction in force per gram of the weight of the pad is therefore approximately 0.60% / gram.

EXAMPLE 4 Foam laminate pad with Flabbercast TM insert A pad identical to that described in example 1 is constructed. In a cavity of 76.4 mm in diameter and 12.7 mm in depth located in the center of the pad, a liquid Flabbercast ™ formulation is poured (Garden Grove, California 92643) which consists of 50 parts by weight of component "A", 100 parts by weight of the component "B", and sufficient plasticizer "C" to equal 100% by weight of the total mixture A / B. The pad is separated and the gel is allowed to cure and solidify. At the end of the healing cycle, the finished pad weighs approximately 59 grams. When evaluated in the artificial hip drop tester, with the insert centered on the artificial trochanter, the maximum force measured in the artificial trochanter is approximately 69% lower than that measured in the artificial hip not cushioned. The reduction in force per gram of the weight of the pad is therefore approximately 1.17% / gram.

EXAMPLE 5 Foam laminate pad with lightweight Flabbercast ™ insert A pad identical to that described in the example is constructed 1. In a cavity of 76.4 mm in diameter and 12.7 mm in depth located at the center of the pad, a liquid formulation Flabbercast ™ consisting of 50 parts by weight of component "A", 100 parts by weight of component "B", is poured, enough "C" plasticizer to equal 100% by weight of the total A / B blend, and approximately 15% of Scotchlite ™ glass beads (Product No. K15, 3M Co., St Paul, Minnesota 55144) of the total weight of the mixture A / B / C. The pad is separated and the gel is allowed to cure and solidify. At the end of the healing cycle, the finished pad weighs approximately 38 grams. When evaluated in the artificial hip fall tester, with the insert centered on the artificial trochanter, the maximum force measured in the artificial trochanter is approximately 66% less than that measured in the non-cushioned artificial hip. The reduction in force per gram of the weight of the pad is therefore approximately 1.74% / gram.

EXAMPLE 6 Foam laminate pad with high-cushioning polyorniornene rubber insert A pad identical to that described in the example is constructed 1. In a cavity of 76.4 mm in diameter and approximately 12.7 mm in depth located at the center of the pad, a piece of high-cushion polyurethane rubber with hardness of Shore A 40 is attached (Rubber Associates, Inc., Baberton, Ohio) , in addition to approximately 76.4 mm in diameter and approximately 12.7 mm in thickness, by means of the same tape with adhesive on both sides 3M # 343 (3M Co., St. Paul, Minnesota 55144) used to laminate the foam layers. The finished pad weighs approximately 80 grams. When evaluated in the artificial hip fall tester, with the insert centered on the artificial trochanter, the maximum force measured in the artificial trochanter is approximately 42% less than that measured in the non-cushioned artificial hip. The reduction in force per gram of the pad is therefore approximately 0.52% / gram.

EXAMPLE 7 Foam laminate pad with high cushion butyl rubber insert A pad identical to that described in the example is constructed 1. In a cavity of 76.4 mm in diameter and approximately 12.7 mm in depth located at the center of the pad, a piece of high-buffered butyl rubber of Shore A hardness 40 (Rubber Associates, Inc., Barberton, Ohio 44203) is attached. approximately 76.4 mm in diameter and approximately 12.7 mm in thickness, by means of the same tape with adhesive on both sides 3 M # 343 (3M Co., St. Paul, Minnesota 55144) used to laminate the foam layers. The finished pad weighs approximately 80 grams. When evaluated in the artificial hip fall tester, with the insert centered on the artificial trochanter, the maximum force measured in the artificial trochanter is approximately 40% less than that measured in the non-cushioned artificial hip. The reduction in force per gram of the weight of the pad is approximately 0.5% / gram.

EXAMPLE 8 Foam laminate pad with thermoplastic polyurethane sandwich insert in the shape of a sandwich A pad identical to that described in the example is constructed 1. In a 76.4 mm diameter cavity and approximately 12.7 mm depth located in the center of the pad, two pieces of approximately 6.35 mm thickness of thermoplastic polyurethane sandwich TPU ™ (Hexcel Corporation, Pleasanton, California 94588) each piece with a cell size of about 6.35 mm and a nominal density of about 12.81 kg / m3 and further about 76.4 mm in diameter and about 12.7 mm in thickness, they are stacked one on top of the other and attached to the pad by means of the same Tape with adhesive on both sides 3M # 343 (3M Co., St. Paul, Minnesota 55144) used to laminate the foam layers. The finished pad weighs approximately 26 grams. When evaluated in the artificial hip fall tester, with the insert centered on the artificial trochanter, the maximum force measured in the artificial trochanter is approximately 56% less than that measured in the non-cushioned artificial hip. The reduction in force per gram of the weight of the pad is therefore approximately 2.15% / gram.

EXAMPLE 9 Foam laminate pad with viscoelastic foam insert A pad identical to that described in the example is constructed 1. In a 76.4 mm diameter cavity and approximately 12.7 mm deep in the center of the pad, one piece of CONFOR ™ CF-47 polyurethane foam (AeroE.ARSpecialty Composites, Indianapolis, Indiana 46268) of approximately 92.91 g / l a Shore 00 durometer hardness of approximately 20, in addition to approximately 76.4 mm in diameter and approximately 12.7 mm in thickness, is bonded by means of the same tape with adhesive on both sides 3M # 343 (3M Co., St. Paul, Minnesota 55144) used to laminate the foam layers. The finished pad weighs approximately 16 grams. When evaluated in the artificial hip fall tester, with the insert centered on the artificial trochanter, the force measured in the artificial trochanter is approximately 66% less than that measured in the artificial non-cushioned hip. The reduction in force per gram of the weight of the pad is therefore approximately 3.88% / gram.

EXAMPLE 10 Foam laminate pad with PVC plastisol gel insert A pad identical to that described in the example is constructed 1. A sample of PVC plastisol gel is cut from a seat cushion model A10305 marked with the U.S. Patent. 5,252,373, from Sports Med (Birmingham, Alabama 35222). A pad insert is manufactured by first heating the gel to a temperature of about 176.6 degrees C in a laboratory beaker until it is liquefied, then pouring the hot liquid into a circular metal mold of approximately 76.4 mm in diameter and approximately 12.7 mm deep, and then allow the gel to cool to room temperature whereby it returns to its original soft gel state. The cooled gel, approximately 76.4 mm in diameter and approximately 12.7 mm in thickness, is removed from the mold and attached to the bottom of the cavity of 76.4 mm in diameter and 12.7 mm in depth located in the center of the pad by of the same tape with adhesive on both sides 3M # 343 (3M Co., St. Paul, Minnesota 55144) used to laminate the foam layers. The finished pad weighs approximately 61 grams. When evaluated in the artificial hip drop tester, with the insert centered on the artificial trochanter, the maximum force measured in the artificial trochanter is approximately 71% less than that measured in the artificial hip not cushioned. The reduction in force per gram of the weight of the pad is therefore approximately 1.6% / gram.

Claims (9)

NOVELTY OF THE INVENTION CLAIMS

1. - A protective pad to protect a previously defined area of the human body against impact forces, the pad has an inner surface, an outer surface and a thickness; the pad is constituted by a first layer of relatively high density closed cell polymer foam, a second layer of relatively low density closed cell polymer foam and characterized in that it includes at least one absorbent insert of elastic energy, the layers and The insert is joined to provide a relatively light weight pad, with a relatively high resistance to impact forces and a relative comfort when applied to the human body area. 2.- A protective pad, which has a thickness and a weight, to protect a previously defined area of the human body against impact forces and which provides a force reduction of at least 40 percent, the pad is less than 20 millimeters in thickness and less than 100 grams by weight, the pad has a strength reduction ratio in percent by weight in gram of the pad, as measured in a fall impact tester in an artificial hip, preferably around 0.25 per cent. percent per gram to 8.00 percent per gram, most preferably 0.40 percent per gram to 6.00 percent per gram, most preferably 0.50 percent per gram to 6.00 percent per gram. 3. The pad according to claim 1 or 2, further characterized in that said pad is constituted by one or more force damping inserts. 4. The pad according to any of the preceding claims, further characterized in that the insert is characterized by: a) polyolefin foam, plastic foam, elastic rubber foam, high-cushion rubber, high-cushion polyurethane, gel curative polyurethane, high-cushion polyvinyl chloride plastisol gel, visco-elastic foam, or elastic thermoplastic honeycomb laminate; b) low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymers, ethylene methylacrylate copolymers, ethylene, polypropylene ionomers, or polypropylene copolymers; c) a foam made of natural rubber, butyl rubber, synthetic polyisopropene, polybutadiene, polynorbornene, styrene-butadiene, neoprene, acrylonitrile rubber, polyurethane, or plasticized polyvinyl chloride; d) a high-cushioning material made of synthetic polyisopropene, natural polyisoprene, polybutadiene, butyl rubber, polinorbornene, ethylene-propylene diene monomer rubber, or styrene-butadiene rubber, combined with high levels of oils, plasticizers or fillers such as black of smoke; e) the high-buffered polyurethane composition formed by the reaction of substantially linear, slightly branched polyols, having hydroxyl end groups and having average molecular weights in the range of 600 grams per mole to 1200 grams per mole with aromatic diisocyanate in minor amount than the stoichiometric amount; f) Sorbothane®; g) a curative polyurethane gel derived from a three component liquid material having an aromatic diisocyanate terminated in a glycol solution component, a polybutadiene polyol solution component, and a plasticizer component constituted by a mixture of dialkyl and alkyl carboxylates; h) a plasticisol gel of high-polyvinyl chloride prepared from a dispersion of polyvinyl chloride resin of particularly fine particle size, dispersed in a plasticizer liquid and also constituted by a larger portion of plasticizer and a smaller portion of resin of polyvinyl chloride; i) a viscoelastic foam that is subsequently constituted by an open cell polyurethane base material; or j) a thermoplastic honeycomb core material laminated between two plastic films by the use of heat, adhesive, or both. 5. The pad according to any of the preceding claims, further characterized in that the first layer has a density of 128 to 192 kilometers per cubic meter, and the second layer has a density of about 32 to 80 kilometers per cubic meter. 6. The pad according to any of the preceding claims, further characterized in that it is constituted by a plurality of reference lines through the outer surface and partially through the thickness to provide a substantial flexibility and adaptation to the area of the body covered by the pad, while maintaining significant resistance to impact forces. 7. The pad according to any of the preceding claims, further characterized in that it is constituted by a plurality of open areas that extend through the thickness to provide the ventilation capacity and heat dissipation that arises from the area of the human body which is covered by the pad, while maintaining significant resistance to impact forces. 8. The pad according to any of the preceding claims, further characterized in that it is constituted by a garment attached to the pad, the garment consisting of a fabric that maintains by capillary perspiration away from the body. 9. The pad according to any of the preceding claims, further characterized in that the insert is constituted by a non-elastic cushioning material such as a ptyrene foam.