Patent Application
20050050617
1. Field of the Invention
The invention relates to a method of making a custom fitted helmet. More particularly, it relates to a method for making a custom fitted helmet having an impact energy absorbing liner having an inner surface that substantially conforms to the shape of the wearer's head.
2. Description of Related Art
Helmets having an impact energy absorbing liner are known for all sorts of applications, including cycling, football and other contact sports, medical intervention for persons prone to seizures, industrial protection such as for manufacturing and construction workers, military and other aircraft pilot protection, etc. In all of these applications, the impact energy absorbing liner is designed to absorb and/or dissipate energy from an impact at the outer shell of the helmet before it is transmitted to the wearer's head. In this manner the wearer's head is at least partially shielded or protected from what otherwise would be the full impact force resulting from the impact.
Conventionally, helmets are supplied in a plurality of standard sizes, e.g., large, medium, small. Sometimes the standard sizes are based on average head circumference, e.g. 14, 14.5, 15, 15.5, 16, inches, etc. A problem with this method of sizing helmets is that the helmets are sized based on universal standards that are not specific to any individual who will actually wear and depend on the helmet for head protection. While a standard sized helmet may provide adequate protection in some instances, it is not fitted to the unique shape and contour of the particular wearer's head, and therefore is prone to fit too tightly in certain aspects or along certain locations of the head while fitting too loosely in others. A too loosely fitting helmet can be as or nearly as catastrophic during an impact as wearing no helmet at all, because the initial impact against the outer helmet shell can be transferred to the head during a second impact between the head and the loosely fitting interior surface of the helmet. Whereas a too tightly fitting helmet is uncomfortable to the wearer and can actually cause traumatic injury.
Currently, “off-the-shelf” helmets are fitted so that they fit snugly in the tightest dimension of the head—this could be from front to back, Or it could be from side to side. The other dimension (front to back or side to side) is then looser—often with a gap of ½ inch or more on each side. This gap is often filled with non-energy-absorbing foam. As an example, a high performance ski helmet typically has approximately 1 inch of energy-absorbing polymer. The ½ inch of unused space on each side of the helmet comes at a high price from an energy absorbing standpoint, because even at moderate impact speeds (e.g. 6 m/s) that extra ½ inch of energy-absorbing foam would result in about a 30% improvement in g-force attenuation prior to reaching the wearer's head. At higher speed impacts the improvement would generally be higher due to the fact that thinner foam will ‘bottom out’ sooner as impact speed increases.
For these reasons, it is important and desirable that the inner surface of the helmet fit as uniformly and snugly as possible about the shape and contour of the individual wearer's head, without being so tight as to result in discomfort or injury. Conventional methods of making a custom fitted helmet include providing a preformed elastomer sack on the inner surface of a helmet shell, and then placing this assembly over a wearer's head with a shell cap placed in between the head and the elastomer sack. The purpose of the shell cap is to approximate the thickness of a subsequently-applied impact absorbing liner and to ensure there is sufficient space for such a liner between the elastomer sack (once rigidized) and the wearer's head within the helmet shell. In this method, the part of the helmet that actually will contact the wearer's head is not custom fitted to the head, therefore this helmet is subject to similar loosely and tightly fitting regions as described above. Other methods are known where an expandable foam is provided to expand in a pouch adjacent the wearer's forehead, but the remainder of the head-contacting regions are not custom fitted to the wearer's head. Further, in this method foaming is actually performed adjacent the wearer's head which is cumbersome to perform, and uncomfortable for the wearer.
Conventionally, helmets have been fit to a wearer's head either by shimming the inside of the helmet using energy-absorbing or comfort fitting foam pieces of varying thickness until the proper fit is achieved, or by installing a series of foam pieces of different thickness to provide a proper fit. There are two disadvantages of these methods: 1. It is difficult when fitting a helmet to know when you have achieved the proper fit. It is a trial and error process that requires more training than is typically available in retail stores. An improperly fitted helmet can lead to serious consequences. 2. Energy-absorbing foam is more effective if it is in one piece. The reason for this is that a significant amount of energy is absorbed in the foam by pumping air through foam—the larger the piece of foam, the longer the path the air must take, and the better the energy-absorption If the foam is in several layers or discrete pieces, it is easier for the air to escape and the energy-absorption properties are reduced.
Some manufacturers attempt to fit their helmets to wearer's heads using “fitting pads” of highly compressible foam that has no appreciable energy-absorbing capability. These fitting pads help keep the helmet tight on the head rather than provide an additional layer of energy-absorptive material. As will be apparent from the above discussion, the use of any more than a minimum of fitting-foam is a waste of critical space in a helmet that could be used to absorb additional energy which could save a life or eliminate a debilitating brain injury.
Still another approach is to use inflatable air bladders that when inflated properly can provide enough pressure to hold the helmet firmly on the head, yet not so much pressure that the helmet fit is uncomfortable. The air bladders, however, are not energy absorbing in the traditional sense, and again, the extra space that they take could be used for energy-absorption
There is a need in the art for a method of making a custom fitted helmet that is economical and comfortable to the wearer, where the energy absorbing liner that actually contacts the wearer's head is snugly and uniformly fitted to the shape and contour of the head.
As used herein, when a range such as 5 to 25 (or 5-25) is given, this means preferably at least 5 and, separately and independently, preferably not more than 25.
The method of the present invention includes first making a headform that conforms to the shape of the wearer's head. The headform is made by positioning or wrapping an appropriate shape-forming means over and against the wearer's head. When the shape-forming means is applied to the head, it is in a softened or flexible state such that it can bend or flex or stretch to conform to the unique contour of the individual head to which it is being applied. Once the shape-forming means has been applied and conformed snugly to the shape and contour of the individual's head, it is hardened or rigidized such that it is no longer soft or flexible, thereby yielding a hardened headform 60 that conforms or substantially conforms to the shape and contour of the wearer's head.
Once hardened, the headform is carefully removed from the wearer's head so as not to break or deform the hardened headform, except for a scissor cut which may be employed to aid removal of the headform as described below. (It is noted the headform may undergo additional hardening or curing after it is removed from the wearer's head). The headform is then used, in a manner described below, to mold (or to prepare a mold for) an impact energy absorbing liner for a helmet that has an inner surface conforming or substantially conforming to the unique shape and contour of the head from which the hardened headform was made. Alternatively, in a further preferred embodiment described more filly below, the hardened headform, which is representative of the contour of the head from which it was made, can be scanned by suitable scanning/digitizing equipment to generate a computer-readable data file of a surface map of the headform, corresponding to the wearer's head. This data file is then used to direct CNC machinery, or other computer controlled milling device or tool, to machine a pre-made energy absorbing liner “blank” so as to provide an inner surface thereof having a complementary contour to the wearer's head
As used herein, the shape-forming means can be a stretchable beanie cap that is coated or impregnated with a curable polymeric material, a heat-softenable plastic sheet, or a strip or plurality of strips of curable tape that are wrapped about the wearer's head to provide a headwrap. Each of these is now described in detail.
Referring to
The beanie cap 10 can be made from an elastic polymeric fabric, such as the conventional Spandex™ or Lycra™ fabrics known in the art, alternatively glass fibers and fabrics can be used. In a preferred embodiment, the fabric used in beanie cap 10 is a knitted polyester fabric. Typically it is either knitted or assembled with fabric cut on the bias so the fabric has an elastic property and can stretch so as to conform tightly to the head and accommodate variations in head shapes. The beanie cap 10 is coated, preferably impregnated or saturated with a curable polymeric material, such as a curable polymer resin, that cures to a hardened state. In a preferred embodiment, the curable material is a moisture or water curable polymer that cures to a hardened state on exposure to moisture. U.S. Pat. No. 5,228,164, incorporated herein by reference, describes a knitted fabric material impregnated with a water curable polymer resin that is suitable for use in making the beanie cap 10 of the present invention. Alternatively, a suitable knitted polyester fabric material for making the beanie cap 10 is available by Carolina Narrow Fabric Company (Winston Salem, N.C.). The fabric is impregnated with a water-curing urethane polymer. The water curable polymer cures slowly when exposed to moisture in the air, or rapidly if water is applied directly to it. Additionally, other suitable curable polymeric materials can be used in the beanie cap 10 according to the invention, and such materials can be selected by a person having ordinary skill in the art without undue experimentation For example, other light or heat curing polymer resins can be used.
As supplied, the beanie cap 10 has a generally tubular structure that is open at one end and terminates at the other end in a closed, substantially dome shape portion 12 as evident from
Alternatively, the beanie cap 10 is provided having no such roll 14, such that its tubular length is not rolled up. In this embodiment, the beanie cap 10 is stretched over the wearer's head, and after it is tightly fitted, a terminal portion of the tubular length of the cap may be folded up or back on itself or cut away so as not to cover the wearer's eyes and to facilitate removal of the hardened headform once it is complete.
Once the beanie cap 10 is stretched snugly over the contour of the wearer's head 20, the coated or impregnated polymeric material of the beanie cap 10 is cured or allowed to cure to yield a hardened headform 60 from the beanie cap, in the shape and contour of the wearer's head 20. When the preferred water curable resin is used, the beanie cap 10 preferably is submerged or dipped once into warm water to initiate the curing process prior to applying the beanie cap to the wearer's head. Additionally, hot water can be sprayed onto the beanie cap 10 once it is applied to the head to further accelerate curing. Water vapor or ambient moisture also can be used but will result in a slower-rate cure, which may be desirable in some applications, e.g. if minor adjustments are to be made to the beanie cap against the wearer's head as the cap is cured.
After the headform 60 has hardened, it is carefully removed from the head and used in subsequent molding or scanning operations described below. To remove the hardened headform it is sometimes necessary to cut the headform (e.g. with scissors) adjacent the back of the head to facilitate removal. If desired, apiece of flexible tubing 15 such as polyethylene tubing can be placed along the centerline of the rear of the person's head as a scissor guide prior to fitting the beanie cap 10 over the head. (
Because the beanie cap 10 is coated or saturated with a polymeric resin, it is desirable to place a barrier over the wearer's head 20 prior to fitting the beanie cap 10 thereover. Such a barrier 30 is shown schematically in
Preferably, the barrier 30 has an elastic or stretchy property so it can be snugly and tightly fit against the wearer's head in order to minimize or prevent spacing defects between the finished headform 60 and the wearer's head. Once the barrier 30 is in place, the beanie cap 10 is placed over the head 20 (and over barrier 30) and the process is completed as described above. To protect the person being fitted from water, a smock or protective covering should be worn. Gloves should be used when fitting the beanie since the resin will stick to hands and can cause irritation.
Initially, the heat-softenable plastic sheet 40 is heated above its softening temperature, typically to 65-70° C. Once softened, the heated plastic sheet 40 is draped over the head as described above and shown in
The tape 50 is wrapped around the head 20 as shown in
Because the resin will cure (and consequently the tape will rigidize) quickly after being immersed in water, a skilled technician will be required to apply the tape properly before it has rigidized. In this embodiment, a certain level of practice is anticipated on the part of the technician to develop a sufficiently rapid wrapping technique.
Irrespective of which of the above shape-forming means is used to provide the hardened headform, care must be taken to cover the proper amount of the head so that the subsequently made energy absorbing liner (molded from the headform, whose mold is made using the headform, or made using CNC machinery as described below) complies with the proper coverage standards and suitably covers the appropriate portions of the head. For example, for motorcycle helmets, the highest coverage standard is Snell M2000 or DOT FMVSS 218, for football helmets it is ASTM F429-01 or NOCSAE Doc. 002-96 m98, and for bicycle helmets it is ASTM F1447-99a or CPSC Prt 1203.
Also irrespective of which of the above shape-forming means is used to provide the hardened headform, preferably a clearance is provided to position a thin layer of comfort foam spacer or spacer(s) to provide for wearer comfort and allow for air circulation, as well as to accommodate the aesthetic lining or upholstering material that will cover all or part of the inside surface of the helmet. This clearance can be provided by placing a tight fitting elastic hood 65 as seen in
Once the hardened headform has been made using any of the shape-forming means described above, it can itself be used as the “male” member, together with a suitable “female” member, of a mold for molding the impact energy absorbing liner for the helmet. Alternatively, the hardened headform can be used as a mold cavity (previously occupied by the wearer's head) into which plaster or some other molding compound is poured, which will itself harden and then will be used as the “male” member of the mold for making the energy absorbing liner. Each of these methods is now described with respect to
In the first method, where the headform is itself used as the “male” member 102 of the mold, the headform is positioned adjacent and spaced a distance from the concave inner surface 104 of a “female” mold member 103 such that the exterior surface 105 of the headform and the inner surface 104 of the “female” mold member define a molding space 108 therebetween for molding the energy absorbing liner. The molding space 108 will have very close to the same dimensions as the finished impact energy absorbing liner as will become evident. When using the hardened headform 60 as the “male” member 102 of the mold, the exterior surface of the headform is sanded to eliminate defects such as exterior bumps, ridges, and wrinkles. Any holes in the headform also should be tightly taped both inside and out so that the expanding foam will not cause them to depress. Typically, the headform is then filled with a hardening material and a pipe or other handle is suspended in the hardening material until it is hardened. The pipe/handle allows the headform to be held and articulated. A layer of stretchable plastic or rubber maybe stretched over the headform to create clearance for inserting foam spacers for air circulation if the wearer's head was not previously provided with an elastic hood 65 to provide such clearance as described above.
In the second method, Plaster of Paris (preferred) or other suitable plaster or curable/hardening material is poured or provided in its uncured state into the cavity defined by the hardened headform, and is then cured to provide a male fixture in the shape of the wearer's head from which the headform was made. In order to prepare the headform to cast the male fixture from plaster or other suitable material, it is important first to seal the headform with an appropriate sealant to make it water tight. If desired, a pipe or other handle structure can be inserted into the yet-uncured Plaster of Paris material and suspended in place until the plaster dries to facilitate handling and fixturing. When the plaster has cured, the hardened plaster fixture is removed from the headform and is lightly sanded to smooth and to remove ridges and irregularities. If the headform was hardened over the wearer's head without the elastic {fraction (1/8)} inch to {fraction (1/4)} inch thick hood 65 in place (see above and
The “female” mold member 103 can be a conventional female mold member having a cavity 110 for molding foam or other resinous energy absorbing materials, e.g. as shown in
Returning to
To make the energy absorbing liner, the “male” member 102 is positioned such that its exterior surface 105 is located adjacent and spaced apart a distance from the concave inner surface 104 of the “female” mold member 103, such that the exterior surface 105 of the “male” member 102 and the inner surface 104 of the “female” member 103 define a molding space 108 therebetween having a substantially spheroid shape. To ensure uniformity of the spheroid molding space, the “male” member 102 and mold cavity 110 can be assembled to a press 150 as shown in
Next, a curable compound is provided or injected into the spheroid molding space 108 to substantially fill that space, and is cured or allowed to cure to form the desired impact energy absorbing liner. Most preferably, the curable compound is a liquid foam precursor composition that cures and expands to form an energy absorbing foam.
The most preferred foam is a semi-rigid viscoelastic foam made from a two-part foaming composition, preferably, one part being isocyanate and the other part being a polyol or mixture of polyols. Most preferably, the foam is Zorbium™ foam available from Team Wendy, LLC in Cleveland, Ohio. Zorbium™ is an energy-absorbing foam that, unlike expanded polystyrene (EPS), exhibits substantially 100% crush recovery following an impact, yet it is still effective to absorb low to high energy impact forces (i.e. 2 to 4 as well as 4 to 7 m/sec, or anywhere in between) and dissipate much of the impact energy away from the head at the localized region of impact. Zorbium™ crushes more than EPS under low speed impacts, and yet has approximately the same crush as EPS under high speed impacts—it thus provides greater impact protection over a wider range of impact velocities. Less preferably, other known or conventional impact energy absorbing foams or resins can be used, such as EPS or expanded polypropylene (EPP), vinyl nitrile, etc. Generally, when molding EPS or EPP steam is used to heat the precursor polystyrene/polypropylene beads. As the beads soften the soluble hydrocarbons expand to generate the foam. Therefore With EPS or EPP, the mold should be provided with a number of vent holes to permit venting of the steam.
The thickness and density of the impact energy absorbing liner (preferably made from foam, preferably Zorbium™ foam) depend on a variety of factors, perhaps most importantly the anticipated or probable impact velocities, the composition of the outer helmet shell and the site and vector of probable impacts. Arriving at the precise foam composition and thickness for the impact energy absorbing liner involves matching the stiffness and strength of the outer shell with the stiffness of the foam taking into account the most critical impact velocities and vectors.
It is preferred to utilize the plaster fixture made from the hardened headform as the “male” mold member 102 because this fixture more accurately conforms to the shape and size of the wearer's head 20 because it is cast in the same cavity once occupied by the head. Using the headform 60 directly as the “male” member 102 of the liner mold is faster (omits a step) than making and using a plaster fixture, but is less precise and can result in greater irregularity in the finished foam liner. But even if this technique is used it maybe necessary in some cases to stretch an elastic material over the headform as described to allow for more clearance for the foam spacers for air circulation in the helmet.
In a preferred configuration the “female” mold member 103 splits into four sections as shown in
It is important to pre-measure the volume to be foamed to fill the molding space 108. Most preferably, this is achieved by first measuring the volume of the female cavity 110, and then subtracting that portion of the “male” member 102 that is inserted into the cavity 110, whose volume can be determined by water displacement. Once the precise volume of the molding space 108 for the energy absorbing liner is known, the correct amount of the foaming compound can be mixed to achieve the proper density of the finished foam liner that will yield the proper energy-absorbing characteristics.
As shown in
This liner is then fitted into an outer helmet shell and is upholstered with fabric and leather as may be desired to provide a custom fitted helmet for the wearer. A thin layer of soft open cell comfort foam spacer or spacers (conforming to the clearance thickness described above) is typically placed between the upholstery and the impact absorbing foam to provide a space for air circulation, and holes are drilled in the foam to facilitate ventilation Alternatively, if the helmet shell is used as the “female” mold member 103, it will be understood the liner formed therein is not removed.
An alternative, further preferred method for making the custom fitted helmet using the hardened headform also is provided. This method involves scanning the headform to generate a computer-readable data file containing a digitized map of the headform (and therefore of the wearer's head), and using the digitized map to control CNC machinery to provide the corresponding surface contour on the inner surface of a pre-made energy absorbing liner “blank.” This method now will be described in detail.
In conjunction with the following description, reference is made to
Then the headform is delivered to a digitizer or other suitable machine (such as a coordinate measuring machine) capable of scanning the headform using known or conventional methods, most preferably using lasers, to measure the surface dimensions and contour of the headform. The above-noted contour lines and other notation marked on the headform provide suitable reference points for the digitizer to generate a corresponding electronic solid form model of the headform as known in the art. The digitizer is equipped with or coupled to a processor that is capable of generating electronic computer-readable data comprising a digitized surface map of the headform, corresponding to the wearer's head. This computer-readable data is then fed into or used by a computer controller that is coupled to suitable CNC machinery to control the operation of the machinery. The CNC machinery can be, e.g., a CNC router or any other known or conventional type of milling machine or tool that is amenable to CNC control so as to produce, via routing, milling or other machining operation of the machine or tool, an inner surface of a “blank” liner that conforms to the digitized surface map of the headform in the computer-readable data file. Such suitable CNC machinery, including CNC routers, are well known and conventional in the art and their operation will not be further described here.
To produce a custom fitted energy absorbing liner using the suitable CNC machinery described above, an energy absorbing liner blank is supplied and retained in a suitable fixture so that the CNC machinery can operate on the blank based on the information in the computer-readable data file. According to the invention, an energy absorbing liner blank is made, e.g. via molding or other suitable means, whose outer convex surface conforms to the helmet shell in which the liner will be mounted, and whose inner concave surface is generally dome- or hemispherically-shaped The inner concave surface is provided having a relatively small diameter compared to a typical human head. In this manner, the CNC machinery or router can produce a desired inner surface contour based on the digitized headform data map by milling, grinding away or otherwise machining liner material from the inner surface of the blank until the appropriate headform dimensions are achieved Once the desired final inner concave surface has been achieved, the surface is or can be coated with a suitable coating to make it impermeable to moisture.
Alternatively, the energy absorbing liner blank can be provided as a solid hemispherical form having a convex hemispherical surface and a flat, circular surface with substantially no initial concavity. The operation of the CNC machinery or router to produce the desired inner concave surface of appropriate dimensions based on the digitized headform map proceeds substantially as described in the preceding paragraph, except now the CNC machinery has to grind away a greater volume of material. This embodiment has the advantage that it can be used to accommodate a larger range of head sizes because there is no initial concave inner surface and hence no head that will be too small to use the blank However, this embodiment also results in a substantial waste of liner material due to the additional wasted material that must be removed to produce the desired inner concave surface for a particular wearer.
Alternatively, and most preferably, blanks can be provided in a number of predetermined stock sizes, such as small, medium, large, extra-large, etc., where the size notation refers to the initial dimensions of the inner concave surface in the blank. For example, a small blank may have an inner concave surface whose hemispherical circumference is 15 inches. This size may be suitable, e.g., for persons whose mean head circumference is in the range of 16-17 inches. A medium blank may have an inner concave surface whose hemispherical circumference is 16 inches, and maybe suitable, e.g., for persons having a mean head circumference in the range of 17-18 inches, and so on. (The numerical values used in this paragraph are for illustrative purposes only).
The present method has the further advantage that no hood 65 (see
It is contemplated that a kit for making the hardened headforms 60 can be supplied to retail locations where persons may wish to purchase a custom fitted helmet, and that the other more expensive equipment, digitizer, computer equipment, CNC control equipment, CNC machinery, etc., will be maintained at a fixed location to which hardened headforms can be sent by the retail locations once they have been made. Generally, a person seeking a custom fitted helmet would patronize one of the retail locations, and a technician employed by the retail store would be trained to prepare the headform from the person's head using the kit (one exemplary such kit is described below). Having completed the headform, the technician would permitit to harden or cure, and then send it back to the fixed location where the other equipment is located, for example in a specialized shipping container which may be supplied with the kit. Then, the headform would be used at the fixed location to produce the corresponding custom fitted energy absorbing liner 90. This liner either could be shipped back to the retail location, where the person then could select from a variety of helmet shells into which the liner can be installed, or otherwise the liner can be installed into a desirable helmet shell according to the person's specifications based on, e.g., a catalog selection.
The present invention, including methods and means for producing a precisely fit custom fit helmet has a number of significant advantages. The custom fit feature allows the retailer to reduce his inventory of helmets and yet achieve a perfect fit for his customers. If a retailer has five different styles with five sizes in each and five different colors, and if he keeps two of each in stock, that is an inventory of 250 helmets. With a custom fit helmet according to the invention the retailer could display the same five styles, and have a color chip for perhaps as many as ten or more colors. Because there is precise clearance between the inner surface of the energy absorbing liner and the wearer's head, it is possible to provide a cooling and refreshing flow of air between the helmet and the head. Conventional helmets require thick padding that inhibits the flow of air. There is less padding in a custom fit helmet according to the present invention for a given exterior helmet shell dimension, and more energy-absorbing foam (the energy absorbing liner) than is possible with a conventional helmet by virtue of the fact that there is less comfort foam. This thicker energy absorbing liner leads to a safer helmet. Because the helmet fits snugly, it has less tendency to roll back at high speeds because it is more stable on the head. Also, even with a perfect fit conventional helmet, due to the standardization of the helmet liner typically there is one spot on the head that rubs harder for a particular wearer, where contact between the liner and the head is more intimate, than the rest of the head Over prolonged use, for example during a long motorcycle ride, this is irritating to the wearer. With a custom fit helmet according to the invention, there are no such over-tight spots because the liner is fit precisely to the contour of the particular wearer's head.
The present invention can be used to make an impact energy absorbing liner having an inner surface substantially conforming to the shape and contour of a particular wearer's head for a variety of different helmets used in different applications. In a preferred embodiment, the helmet for which the liner is made as described herein is a motorcycle helmet. Alternatively, the helmet can be a bicycle helmet, football helmet, hockey helmet, skiing helmet, skydiving helmet, equestrian helmet, kayaking helmet, or other sports helmet, a helmet for medical intervention for persons prone to seizures or unconsciousness (narcolepsy), industrial protection helmet (e.g. for manufacturing and construction workers), aircraft helmet including military airplane and helicopter pilot helmets, etc.
The invention includes a kit comprising all of the materials needed to make a hardened headform as described herein using the beanie cap 10. Preferably, the kit includes the resin-impregnated beanie cap 10, a protective barrier 30 (preferably latex or silicone), protective gloves, waterproof apron and cape to shield the wearer's body, serrated scissors for cutting the hardened headform, a scissor guide (preferably plastic tube or plastic strip), scissor cut resealing means (preferably super glue or stapler), adhesive tape, a level, a ruler, printed casting instructions and optionally an instructional video.
Although the hereinabove described embodiments of the invention constitute the preferred embodiments, it will be understood that modifications can be made thereto without departing from the spirit and cope of the invention as set forth in the appended claims.
This application is a continuation-in-part of U.S. patent application Ser. No. 10/727,725 filed Dec. 4, 2003, which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/432,193 filed on Dec. 6, 2002, which provisional patent application is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60432193 | Dec 2002 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10727725 | Dec 2003 | US |
| Child | 10933580 | Sep 2004 | US |
