US20080271339A1

US20080271339A1 - Extruded Cushioning Insole

Info

Publication number: US20080271339A1
Application number: US11/743,478
Authority: US
Inventors: James R. Fischer
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-05-02
Filing date: 2007-05-02
Publication date: 2008-11-06

Abstract

The invention is an extruded cushioning insole for footwear. The insole disperses the weight of an individual more evenly across the surface of their foot and reduces the impact forces on the feet when walking, running or jumping. The insole is integrally extruded in a one-piece construction. One insole embodiment includes a flexible upper pad with a plurality of downwardly extending tubes that each form a collapsible internal chamber. Another insole embodiment has a solid main body with a flat upper surface and a contoured lower surface formed by thinner and thicker regions of the insole. Another insole embodiment has a flat upper surface and a convex lower surface formed by a collapsible internal disc-shaped chamber. The convex surface is generally flat when compressed.

Description

TECHNICAL FIELD OF THE INVENTION

This invention relates to an extruded cushioning insole for footwear and a process of making the same, the insole having an integral construction, a crush resistance and resilience to provide effective cushioning for the useful life of the footwear.

BACKGROUND OF THE INVENTION

The human foot is a complicated structure with many bones, muscles and tendons. People that are on their feet for long periods of time recognize the benefit of a shoe or shoe insert that provides a degree of cushioning to absorb the constant weight and pounding experience by their feet throughout the day. This cushioning is particularly appreciated when a person is on a hard surface such as concrete floor, sidewalk or road. Yet, the bottom of the foot is not flat, and includes a heel, arch, ball and toes to form an undulating surface. This structure creates areas of high or concentrated pressure and forces and areas of lower pressure and forces. Areas of the foot that experience higher pressures can tire and become sore more quickly.
Shoe insoles and inserts are typically placed over the sole or mid sole of a shoe, and engage the bottom of the foot to provide two types of cushioning. First, the insert should dissipate the shock of any dynamic forces experienced by the foot when the shoe strikes the ground, such as when a person is walking, running or jumping. Instead of sudden jarring impacts by the foot against the sole of the shoe, the forces are more gradually transmitted as the insert compresses. Second, the insert should distribute forces and pressures more evenly across the bottom of the foot. Lower portions of the foot compress the insert more than higher areas of the foot so that the insert tends to engage the entire bottom surface of the foot, and distribute pressure more evenly across that surface. This cushioning takes place even when the person is standing still.
A problem with cushioning insoles and inserts is their short useful life. The useful life of the insert is typically shorter than that of the associated footwear in which they are placed so that the inserts need to be periodically inspected and replaced. While conventional inserts have a typical useful life of one to six months, tennis or jogging shoes have a typical or normal useful life of about six months to two years and dress shoes and boots have a typical or normal useful life of about one to five years depending on a variety of factors such as the quality, craftsmanship and materials used to make them, the frequency they are worn, the environment in which they are worn, the activity level and degree of ruggedness when worn, the care given them, and the weight and perspiration of the wearer. Yet, consumers either forget to inspect their inserts, or are ill-equipped to determine when they should be replaced. Many people simply put inserts in their shoes and forget about them. If they do think to inspect the inserts, they have difficulty determining their unloaded thickness and compression resistance when the inserts are inside the footwear. People do not take the time to regularly remove the inserts from their shoes, and properly inspect them. Moreover, even when the inserts are removed, the inspection is more a matter of guesswork than an informed decision. A person may not have a new insert to use as a reference for comparing the shape and thickness of the used insert. People simply guess if the insert looks like it is crushed too much. Even if there is an available reference, they have difficulty visually gauging the percentage of recovery remaining in the insert or the degree to which it has been permanently crushed. The sides of the insert can retain their original cushioning shape and thickness while middle areas that experience the higher pressures can be significantly crushed so that its cushioning effectiveness is significantly reduced or lost. In addition, even if the insert does return to its original thickness, the insert may have lost its compression resistance or load bearing capacity. For example, foam is typically measured in units of indentation load deflection (ILD) or indentation force deflection (IFD). Although many consumers are not even aware that this type of cushioning loss can occur, those that are still likely to rely on guesswork in evaluating the degree of this cushioning loss. Testing labs with expensive machines are typically used to measure compression resistance. As a result, consumers continue to wear their cushioning inserts well after they deteriorate and perform ineffectively. Even though people buying cushioning inserts believe they are taking measures to improve their health, they can still end up with and suffer from chronic foot, ankle, knee, hip and back problems.
Cushioning insoles and inserts come in a wide range of structural complexity and price. Less complex and expensive inserts include a single sheet of resilient foam. Initially, the foam sheets help dissipate impact forces from running, jumping and walking, and also help distribute forces more evenly across the bottom of the foot such as when the person is standing still. However, as these foam sheets are compressed by the weight of the person, and repeatedly cycled as the person shifts their weight from one foot to the other, the sheets quickly lose their cushioning effectiveness. The sheets experience a loss in unloaded thickness due to crushing, particularly in higher pressure areas. The sheets can also experience a loss in compression resistance as measured in ILD/IFD. Significant cushioning losses can occur within a few months. The rate at which the inserts lose their cushioning effectiveness increases with the weight and activity level of the person. Yet, the feet and joints of heavier and more active people benefit the most from a proper cushioning insert. Consequently, although these less complex cushioning inserts are generally affordable, they are ill-equipped for many, if not most, people.
More complex insoles or inserts typically include multiple pieces of material. Each piece is separately formed. Individual pieces may be made of different materials such as metal, rubber, plastic, cloth fabric, foam or gel, and are shaped for a specific purpose. Some pieces are for areas that experience higher pressures, such as the heel or ball of the foot. Some pieces are made to provide structural support or stability, such as an arch support. The various pieces are then matched, placed in their desired orientation, and glued or otherwise attached to each other. The manufacturing process for more complex inserts require more inventory, materials, labor, equipment and time. An example of such an insert is disclosed in U.S. Pat. No. 4,674,204, the disclosure of which is incorporated by reference. Accordingly, the cost of these inserts is significant. Many people do not see the value of the inserts, and avoid using them until they begin suffering from chronic foot, knee or back pain. Unfortunately, the time for the preventing these ongoing daily ailments has passed.
Some inserts include a gel in an elastic or stretchable material to provide cushioning. A problem with these inserts is leakage and cost. A gel leak can stain, gunk up or otherwise ruin the footwear. Contact with liquid gel can also cause skin irritation for some people. Yet, the insert is exposed to heat and sweaty acids that can break down the material containing the gel or cause the gel to tear or otherwise deteriorate. These insets must also endure prolonged cyclical loading and unloading without leaking or deteriorating. Trimming gel inserts is not typically suggested, and can result in a leak of a liquid gel insert. Thus, many people avoid these types of inserts because of possible leaks, gel deterioration, damage to the footwear and the cost of the insert.
A further problem with cushioning insoles and inserts is adaptability. The inserts should be easily adaptable for use in a wide variety of footwear, such as walking shoes, dress shoes, boots, or tennis shoes. This is particularly problematic for more complex or multi-piece inserts. These inserts can include metal or hard molded pieces that are not generally intended to be cut or trimmed. They can also include a cloth fabric that will unravel if cut or trimmed. Other inserts are contoured with a raised perimeter around the heel and arch regions sized for a specific foot having a specific width. The contoured perimeter is not intended to be trimmed, and restricts the movement of the foot in the footwear. As a result, the inserts have a defined “take-it-or leave-it” shape that is not adaptable to the shape of a specific shoe, boot or sneaker. Forcing an insert that is too wide or too long into footwear can kink the insert or shoe and result in discomfort, and damage the shoe insert. Inserts that are too narrow or short relative to the shoe can shift inside the shoe and result in similar problems.
A still further problem with cushioning inserts is that they do not accommodate a wide variety of people. While people come in all shaped and sizes, inserts are often designed for the “average” person. If the insert is contoured to the shape of a foot, the contouring is for the foot of the average person. The thickness and stiffness or rigidity of the insert is also intended for a person of average weight. The inserts are not intended for children or petit or larger adults. Heavier people will bottom out the insert, which reduces the effectiveness of the insert and can damage the insert and reduce its life. Lighter people do not compress the rigid material significantly, which reduces the cushioning effect of the insert.
A still further problem with insoles and inserts is that they inhibit the flexibility of the foot and shoe. Components that are intended to be stiff or rigid to provide an arch support or absorb shock tend to resist bending.
A still further problem with insoles and inserts for footwear is quick recovery. To perform properly, the insert must quickly return to its normal or unloaded position so that it is ready to provide cushioning for the next step or jump of the person. Yet, many materials have a recovery rate that is too slow for the pace of a person that is walking or running.
A still further problem with conventional insoles and inserts is odor absorption. Inserts with cloth of leather materials will absorb the sweat and odors of the feet. Some foam inserts also tend to absorb moisture and odor. These inserts will have to be disposed of for sanitary or hygiene reasons before the complete cushioning life of the insert.
A still further problem with cushioning insoles or inserts is heat and sweat resistance. The inserts should be made of materials that withstand prolonged exposure to body heat and sweat. The recovery rate and compression resistance of the material cannot deteriorate when exposed to the heat and sweat of the human body.
A still further problem with cushioning inserts is that they should not contribute to the growth of mold and bacteria in the shoe. The structure of the insert should not collect moister, so as to cultivate the growth of mold and bacteria. Yet, many inserts have a flat bottom surface that can trap moisture. The overall structure of the insert does not allow the materials below the insert to breath and dispel the moister that cultivates mold and bacteria.
The present invention is intended to solve these and other problems.

BRIEF DESCRIPTION OF THE INVENTION

The present invention pertains to an extruded cushioning insole or insert for footwear. The insole disperses the weight of an individual more evenly across the surface of their foot and reduces the impact forces on the feet when walking, running or jumping. The insole or insert is an integrally extruded, one-piece insert. One insole embodiment includes a flexible upper pad with a plurality of downwardly extending tubes that each form a collapsible chamber. Another insole embodiment has a solid main body with a flat upper surface and a contoured lower surface formed by thinner and thicker regions of the insert. Another insole embodiment has a flat upper surface and a convex lower surface formed by a collapsible internal disc-shaped chamber. The convex surface is generally flat when compressed.
An advantage of the present extruded plastic cushioning insole or insert is its long life. Its useful life is typically longer than that of the associated footwear. The FPVC plastic material retains its compression resistance and resiliency for a relatively long period of time, even when used by a relatively active or heavier person. The insole should not need to be periodically removed from their shoe, inspected and replaced. When consumers throw away their old shoes or boots, they simply remove the inserts, and insert them in a new pair of footwear. The replacement of the footwear triggers the inspection of the inserts. The consumer does not have to independently remember to inspect the inserts during the life of the footwear.
Another advantage of the present extruded cushioning inserts is ease of inspection. Prior to placing the inserts into a new pair of shoes, the inserts are visually inspected to determine if they have retained their proper shape. The extending tubes have a uniform structure when the insert is in good working condition. Non-uniformity caused by crushing of the tubes in the more central, high pressure areas is easily noticed. The inserts should be replaced when portions of the tubes lose their resilience, and fail to quickly return to their fully extended position and uniform configuration.
Another advantage of the extruded cushioning insole or insert is its ease of manufacture and economical price. The cushioning inserts are formed by a single extrusion process and a punch press. No separate pieces need to be matched and glued or otherwise secured together. Inventory, logistics, material costs, labor, equipment and time are kept to a minimum. The extruded inserts are made of solid materials and contain no substances that can leak or create a mess. By keeping the cushioning inserts economical, many people will begin using them before they start to suffer from chronic foot, knee or back pain.
A further advantage of the present extruded cushioning insole is its adaptability. The insoles or inserts are easily adapted to obtain a proper fit inside a variety of footwear, such as walking shoes, dress shoes, boots, or tennis shoes. Although feet and footwear come in all shaped and sizes, the uniform structure of the integrally extruded inserts and their use of soft FPVC plastic material allows them to be easily cut and trimmed to fit a wide variety of feet and footwear. The cushioning inserts can be pre-cut for specific foot sizes such as for adults or children, and trimmed by the consumer prior to inserting them into their specific pair of shoes or boots. Cut or trimmed areas do not fray, unravel or otherwise deteriorate. As a result, the inserts are easily shaped to snuggly fit inside a wide variety of footwear, without kinking. The inserts remain fixed in place inside the footwear and do not shift around during use. The inserts should not cause foot sores or damage the footwear.
A still further advantage of the present extruded cushioning insert is its adaptability for persons of different weights. By simply increasing the thickness of the flexible pad, height of the tubes, or thickness of the deformable wall of the tubes, the inserts can accommodate the forces associated with wide variety of weights. The thickness and compression resistance of the insert can be selected to accommodate people weighing 30 pounds or 300 pounds. The inserts can be used by children or petit or larger adults. Heavier people do not bottom out the inserts made for them. Lighter people properly compress their inserts and receive the benefit of a sufficient amount of cushioning.
A still further advantage of the present extruded cushioning insole is its flexibility. The insole or insert is made of soft flexible PVC plastic and is free of metal and rigid parts that resist the natural bending of the foot and shoe. The compressible tubes can be positioned laterally to further increase flexibility and help the insert conform to the natural bending motion of a foot or shoe.
A still further advantage of the present extruded cushioning insole and insert is its quick recovery. The inserts quickly or instantaneously return to their normal or unloaded position so that it is ready to provide cushioning for the next step or jump of the person. The recovery rate of the insert is believed to be less than ¼ second, which allows for full recovery between each step even when a person is walking, running or jumping at a fast pace.
A still further advantage of the present extruded cushioning insole is its resistance to odor absorption. The extruded plastic insole or insert does not absorb the sweat and odors of the feet. The insert can be used for its entire useful life without needing to be disposed of for sanitary or hygiene reasons.
A still further advantage of the extruded cushioning insole is that it retains its integrity in the presence of body heat and sweat. The FPVC plastic withstands prolonged exposure to heat and sweat. The recovery rate and compression resistance of the material do not deteriorate when exposed to human body heat or sweaty acids.
A still further advantage of the extruded cushioning insert is that it does not contribute to the growth of mold and bacteria in the shoe. The structure of the insert does not collect moister, so as to cultivate the growth of mold and bacteria. The overall structure and uneven bottom surface of the insert allows moister to escape and the shoe to breathe in a normal manner.
Other aspects and advantages of the invention will become apparent upon making reference to the specification, claims and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view of the present cushioning insole invention positioned inside a conventional shoe having a sole and an upper.

FIG. 2 is a side sectional view of the present cushioning insole invention inside a shoe and cushioningly supporting a foot, and showing the longitudinal higher and lower pressure areas of the foot compressing the shoe insert.

FIG. 3 is a front sectional view of FIG. 1 showing a first embodiment of the cushioning insole inside the shoe.

FIG. 4 is a side sectional view of FIG. 4 showing the lateral higher and lower pressure areas of the foot compressing the shoe insole.

FIG. 5 is a side view of the extruder, water bath, puller, punch press and take-off winder used in the process of forming the various shoe insole.

FIG. 6 is a perspective view of the present cushioning insole.

FIG. 7 is a side sectional view of the first embodiment of the cushioning insole with an upper layer and a plurality of spaced tubes.

FIG. 8 is a side sectional view of a second embodiment of the cushioning insole with a plurality of joined tubes.

FIG. 9 is a side sectional view of a third embodiment of the cushioning insole with a plurality of spaced semi-circular tubes.

FIG. 10 is a side sectional view of a fourth embodiment of the cushioning insole with a plurality of joined rectangular tubes that form a lower layer.

FIG. 11A is a side sectional view of a fifth embodiment of the cushioning insole with a plurality of spaced circular tubes.

FIG. 11B is a side sectional view of FIG. 12 showing the fifth embodiment of the cushioning insole joined to an extruded arch support.

FIG. 12 is a top view of the cushioning insole with portions of its heel and ball regions cut away, and an extruded arch support placed under the mid portion of the insert, such as an upside down portion of insole 170.

FIG. 13A is a top view of the fourth embodiment of the cushioning insole.

FIG. 13B is a side sectional view of FIG. 13A showing the rectangular shaped tubes of the cushioning insole.

FIG. 14 is a top view of the present cushioning insole showing its upper surface marked with size and width designations for trimming the insert to the desired size and width of the individual user.

FIG. 15A is a top view of a sixth profiled embodiment of the cushioning insole extruded from sheet extrusion die.

FIG. 15 B is a side sectional view of FIG. 15A showing its thicker heel and arch regions.

FIG. 16A is a top view of a seventh profiled embodiment of the cushioning insole.

FIG. 16 B is a side sectional view of FIG. 16A showing its thicker heel and arch regions.

FIG. 17A is a side sectional view of an eighth embodiment of the cushioning insole having a uniform thickness, solid interior and flat lower surface.

FIG. 17B is a side sectional view of a eighth embodiment of the cushioning insole having a uniform thickness, solid interior, flat lower surface and a hardened upper surface layer.

FIG. 17C is a side sectional view of a ninth embodiment of the cushioning insole having a solid interior and wavy lower surface.

FIG. 18 is a side sectional view of a tenth embodiment of the cushioning insole having a main body with a flat upper surface and a convex lower surface formed by several internal chamber located proximal to the lower surface.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

While this invention is susceptible of embodiments in many different forms, the drawings show and the specification describes in detail several preferred embodiments of the invention. It should be understood that the drawings and specification are to be considered an exemplification of the principles of the invention. They are not intended to limit the broad aspects of the invention to the embodiments illustrated.
As shown in FIGS. 1 and 2, a human foot 10 has a particular shape with a narrowing front 11 with toes 12, a forward ball 13 from which the toes flex, a middle arch 14 that distributes weight, and a heel 15 positioned below the ankle at the rear. The bottom surface 16 of the foot 10 also has a particular shape with a wider front or ball area 17, a narrowing arch area 18, and a rear heel area 19. Footwear such as a shoe 20 is designed to fit and support the foot 10. A conventional shoe has a closed front 22 that surrounds and supports the front 11 and middle 14 of the foot, and an open rear 23 that receives and supports the heel 15 of the foot. The shoe 20 has opposed sides 26 and 27 that provide lateral support and keep the foot 10 centered when in the shoe. The shoe 20 has a sole 31 that spans the length and width of the shoe. The sole 31 includes a heel 32 at its rear 25, which is frequently sized to raise the heel 15 of the shoe. The sole 31 of the shoe 20 can include a mid-sole that forms an arch support for the foot 10. The shoe 20 includes an upper 35 to secure the foot 10 to the shoe. The sole 31 and upper 35 combine to form the inside 40 of the shoe 20. The top of the sole 31 generally forms the upper surface 42 of the inside 40 of the shoe, against which the bottom surface 16 of the foot 10 rests.
The present invention pertains to an extruded cushioning insole or insert for footwear generally indicated by reference number 50 in FIGS. 1 and 2. The extruded plastic insole 50 has an integral, unibody construction. This integral or single piece insert 50 has a front 51 a rear 52, sides 53 and 54 and a perimeter 55. The perimeter 55 is shaped in general conformity with the shape of the bottom surface 16 of the foot 10 and inside surface 42 of the shoe 20. The insert 50 is cut and trimmed to lay generally flat against the inside surface 42 of the shoe 20. Similar to the shape of the foot 10 and shoe 20, each insert 50 has a narrowing front region 56, a wider ball of foot region 57, a narrower arch region 58 and a heel region 59 as shown in FIG. 6.
The insert 50 is formed by an extrusion and forming process including a conventional plastic extrusion machine 61 as in FIG. 5. The insole 50 is made of flexible vinyl compound (FPVC) plastic. Pellets of FPVC plastic are poured into the extruder 61 and heated to form a molten extrusion material. The barrel and screw of the extruder 61 continuously pushes and heats the molten extrusion material to about 370-380° F. The molten material is at about 380° F. at the gate of the extruder. The hot molten material passes through a die 62 having a desired extrusion profile. The die has a thickness of about 1¾ inches. The molten extrusion material exits the die 62 at a temperature of about 380° F. in the form of an integral molten web or sheet 63 having an untrimed width of about four inches. The molten web 63 enters a conventional water bath 64 that cools and solidifies the web 63 as it moves through the bath 64. The web 63 leaves the bath 64 in the form of a semi-solid, integrally extruded sheet 65 having a temperature of about 150° F. The sheet is pulled along a path of travel through the bath 64 by a conventional puller 66 at a continuous rate of speed of about 4 to 6 feet per minute. The partially cooled, semi-solid sheet leaves the puller 66, and enters a punch press 67 that cuts the sheet to form each of the individual insoles 50. The punch press 67 includes a reciprocating punch that moves both up and down, and back and forth so that the punch travels in unison with the sheet along its path of travel during its cutting engagement with the sheet 65. The punch 67 has a cutting edge with a desired cutting perimeter shape to cut blanks from the semi-cooled sheet 65. The wider ball region 57 is slightly less than the 4 inch wide extruded web 65. After punching out the individual inserts 50, the sheet 65 has a continuous outer web for winding around a takeoff winder 68. These blanks form the extruded, unibody, inserts 50 of the present invention. Each insole 50 has a continuous, integral layer 70. This layer 70 can have a plurality of integral, resilient tubes 80 extending from its lower surface. The tubes 80 can take on different shaped and configurations in different embodiments of the cushioning insole invention 50.
A first embodiment of the insole or insert 50 is shown in FIGS. 3, 4, 6 and 7. This insert 50 has a continuous upper layer 70 and a plurality of hollow, lower tubes 80. The upper layer or flexible pad 70 has a solid body with generally flat, parallel upper and lower surfaces 72 and 74. The layer 70 has a uniform thickness of about 0.06 inch. The upper surface 72 can have a number of upwardly extending, uniformly spaced, gripping ridges, about 10 per inch (not shown) to allow the bottom surface 16 of the foot 10 or a sock to better grip the insert 50. Each ridge has a height of about 0.007 inch. The upper layer 70 is preferably continuous from one end of the insert to the other, and from one side of the insert to the other. The insole 50 can include one or more cutout areas 78 to relieve or avoid pressure from the bottom 16 of the foot 10 in those areas as in FIGS. 6 and 12.
The tubes 80 project down from and are uniformly spaced across the lower surface 74 of the upper layer 70. Each tube 80 is formed by a continuous wall 82 having a uniform thickness of about 0.05 inch. The wall 82 is arcuate and forms opposed side portions 83 and a joining bottom portion 84. The upper layer 70 forms an upper portion or wall of the tube 80. The walls 83, 84 and 70 of the tube 80 surround a hollow interior that forms a longitudinal channel 90 with opposed vented ends 92 and 93. Although most tubes 80 and their channels 90 are continuous across the length of the insert 50, given the particular arcuate shape of the foot 10 and insert 50, some tubes 80 may be broken in the arch region 58, or cut open along the perimeter 53 of the insert. Each tube 80 has a height of about 0.25 inch, so the total uncompressed height of the insert 50 is about 0.3 inch. Each tube 80 has a width of about 0.38 inch, which is the distance between the outside surfaces of its opposed sidewalls 83. Each tube 80 is spaced a uniform distance apart of about 0.18 from its adjacent tube or tubes. This is the width of the spaced section 78 of the upper layer 70 between adjacent tubes 80. Each sidewall 83 forms a deformable wall that supports the upper layer 70. These tubes 80 and their deformable walls 83 are evenly spaced across the width of the insert 50.
This insole 50 is preferably made of FPVC plastic having a specific gravity of about 1.27 as per ASTM D792, and a hardness of about 75 durometers (instantaneous) and 66 durometers (15 seconds) as per ASTM D2240. The plastic has a tensile elongation at break of about 420%, a tensile stress of about 740 psi, and a tensile strength of about 1,800 psi as per ASTM D638, and a tear strength of about 270 lbs/in as per ASTM D624. The plastic has a Clash-Berg modulus or modulus of rigidity of about 18,000 psi as per ASTM D1043, and a compression set of about 23% as per ASTM D395. The plastic has a brittleness temperature of about −47° F. as per ASTM D746, an extrusion melting temperature of about 350° F., and a mold shrinkage of about 0.02 in/in as per ASTM D955. The FPVC plastic is available in pellet form from PolyOne Corporation of Avon Lake, Ohio under its “Geon” B7500 mark.
As shown in FIGS. 3 and 7, the shoe insert 50 has a relaxed position 100 with no weight being applied to its upper surface 72. In this relaxed position 100, the tubes 80 are fully extended to a uniform height of about 0.32 inch. The midpoint of the bottom portion 84 of each tube 80 rests on the upper surface 42 inside the shoe 20. The flexible pad 70 is flat and planar to the surface 42 inside the shoe. When the weight of a foot 10 is placed on the upper layer 80, the bottom 16 of the foot 10 pushes down on the insert 50 and forces it into a compressed position 105 as shown in FIG. 4. In this compressed position 105, the sidewalls 83 of the tubes 80 buckle, and the height of the tubes 80 decreases. The sidewalls 83 tend to buckle outwardly relative to the center of the insert 50 given that they are joined together by their outwardly curved or convex bottom portion 84. This curved portion has an outer radius of about 0.19 inch.
The stiffness or resistance to compression of the deformable walls 83 resist this buckling to create a cushioning effect. The greater the buckling, the greater the amount of upward force exerted on the upper layer 70. In areas of lower pressure 110, the sidewalls 83 of adjacent buckling tubes 80 remain separated and do not touch each other. However, as the height of the tubes 80 is greater than half the distance between adjacent tubes, in areas of high pressure 115, the sidewalls 83 of adjacent tubes do touch each other. A sudden compression of the insert 50 and its tubes 80 will also cause the air inside the channels 90 to be forced out their vent ends 92. Although various embodiments of the insert 50 have a flexible upper layer 70 with the same general top profile view such as that in FIG. 12 to securely fit inside a shoe, the bottom view and tubes 80 can vary to achieve a desired degree of cushioning. The height and width of the tubes 80 and the distance between them can change.
A second embodiment of the insole or insert 150 is shown in FIG. 8. This insert 150 also has a continuous, flexible pad 70 with a uniform thickness of about 0.06 inch, and several evenly spaced conjoined tubes 80. Each tube 80 is formed by a wall 82 having opposed side portions 83 and an arced bottom portion 84. The wall 82 has a uniform thickness of about 0.03 to 0.04 inch. Each tube 80 has a height of about 0.18 inch and a width of about 0.25 inch. The insert 150 has a total relaxed or uncompressed height of about 0.24 inch. Adjacent tubes 80 share a common side portion 83 so there are about 16 longitudinal tubes in a 4 inch wide insole 150. When in a relaxed or extended position 100, each tube 80 has a half circle or hemisphere shape. When in a compressed position, the deformable side walls 83 bend and the bottom wall 84 flattens and buckles.
A third embodiment of the insole 170 is shown in FIG. 9. This insert 170 has a continuous, flexible pad 70 with a uniform thickness of about 0.06 inch, and several evenly spaced tubes 80. The tubes 80 are similar to those of insole 150. Each tube 80 is formed by a wall 82 having opposed side portions 83 and an arcuate bottom portion 84. The wall 82 has a uniform thickness of about 0.03 to 0.04 inch. Each tube 80 has a height of about 0.18 inch and a width of about 0.36 inch. The insert 170 has a total uncompressed height of about 0.24 inch. Adjacent tubes 80 are relatively close together, but do not share a common side portion 83. There are about 11 longitudinal tubes in a 4 inch wide insole 170. When in a relaxed or extended position 100, each tube 80 has a half circle or hemisphere shape. When in a compressed position, the deformable side walls 83 bend outwardly and the bottom wall 84 flattens and buckles.
Insoles 150 and 170 are preferably made of FPVC plastic having a specific gravity of about 1.14 as per ASTM D792, and a hardness of about 55 durometers (instantaneous) and 50 durometers (15 seconds) as per ASTM D2240. The plastic has a tensile elongation at break of about 440%, a tensile stress of about 400 psi, and a tensile strength of about 1,100 psi as per ASTM D638, and a tear strength of about 180 lbs/in as per ASTM D624. The plastic has a Clash-Berg modulus or modulus of rigidity of about 1,000 psi as per ASTM D1043, and a compression set of about 20% as per ASTM D395. The plastic has a brittleness temperature of about −70° F. as per ASTM D746, an extrusion melting temperature of about 330° F., and a mold shrinkage of about 0.03 in/in as per ASTM D955. The FPVC plastic is available in pellet form from PolyOne Corporation of Avon Lake, Ohio under its “Geon” A5500 mark.
A fourth embodiment of the insole or insert 200 is shown in FIGS. 10, 13A and 13B. This insert 200 has a continuous, flexible pad 70 and several evenly spaced rectangular conjoined tubes 80. Each tube 80 is formed by a wall 82 having opposed vertical side portions 83 and a flat horizontal bottom portion 84. The wall 82 has a uniform thickness. Adjacent tubes 80 share a common side portion 83. The bottom portions 84 form a flat lower layer 204 that is parallel to the upper layer 70. When in a relaxed or extended position 100, each tube 80 has a rectangular shape. When in a compressed position, the deformable side walls 83 bend and the bottom layer 204 remains flat. This insole 200 is preferably made of FPVC plastic having characteristics similar to insole 50 or 150, and available in pellet form from PolyOne Corporation of Avon Lake, Ohio under its “Geon” A5500 or B7500 marks.
A fifth embodiment of the insert 300 is shown in FIG. 11A. This insert 300 has a continuous, flexible pad 70 with a uniform thickness, and several lower, evenly spaced circular tubes 80. Each tube 80 is formed by a wall 82 having a uniform thickness. Adjacent tubes 80 do not share a common portion. The upper end of each circular tube 80 is joined to lower surface 74 of the flexible layer 70. When in a relaxed or extended position 100, each tube 80 has a circular shape. When in a compressed position, the deformable side wall 82 bends into a generally oval shape. This insole 300 is preferably made of FPVC plastic having characteristics similar to insole 150, and available in pellet form from PolyOne Corporation of Avon Lake, Ohio under its “Geon” A5500 mark.
The inserts 50, 150, 170, 190, 200 and 300 can be customized to meet the specific needs of an individual. The high pressure areas 57′ and 59′ in the ball and heel regions 57 and 59 are marked and cut away to relieve pressure in those areas as shown in FIG. 12. An arch support is formed by taking the sixth embodiment 300 and adding a portion of the third embodiment 170 in the arch region 58 as shown in FIG. 11B. This combined structure builds up the arch region 58 to provide additional support to the arch 14 of the individual. The flat upper surface 72 of the inserts 50, 150, 190, 200 and 300 are preferably marked with lines for trimming the insert to fit the specific shoe sized of the individual as in FIG. 14.
Although the tubes 80, channels 90 and their deformable walls 82-84 are shown extending longitudinally or from front-to-rear of the insert 50 during the process of manufacturing the inserts 50, the punch press 68 can be rotated 90° so that the tubes, channels and walls ran laterally or from side-to-side. For example, the tubes 80 and channels 90 of the insert 200 run from sided-to-side or laterally in FIGS. 13A and 13B. This lateral arrangement also applies for inserts 150, 170, 190, 200 and 300. The laterally extending tubes 80 channels and walls 82-84 increase the flexibility of the inserts when walking, running and jumping because the insert is more easily bent to conform to the natural bending movement of the foot and shoe.
A sixth, solid profiled construction of the extruded cushioning insert 400 is shown in FIGS. 15A and 15B. The profiled insert 400 has a solid main body with a flat upper surface 472 and a contoured, lower surface 474. The insert 400 has a thickness of about 0.18 inch in its flat front and ball regions 456 and 457, about 0.28 inch in its flat raised arch region 458, and about 0.24 inch in its flat rear heel region 459. A sloped arch region 458′ joins the flat raised arch region 458 to the ball region 457. A flat recessed rearward region 459′ between the arch and heel regions 458 and 459 has a thickness of about 0.18 inch. The forward and rearward ends of this region 459′ are sloped to minimize any concentrations of pressure during use. The body of the insert 400 is continuous from one end of the insert to the other, and from one side of the insert to the other. A second, solid profiled insert 450 or seventh embodiment of the invention is shown in FIGS. 16A and 16B. This insert 450 eliminates the sloped arch region 458′. Instead, the forward end of the arch region 458 is sloped to minimize any concentrations in pressure during use. Insoles 400 and 4500 are preferably made of FPVC plastic having characteristics similar to insole 150, and available in pellet form from PolyOne Corporation of Avon Lake, Ohio under its “Geon” A5500 mark.
In a eighth embodiment, the extruded cushioning insert 500 has a solid main body having parallel upper and lower surfaces 572 and 574, and a constant uniform thickness of about 0.17 inch as shown in FIG. 17A. The insert 500 is preferably coextruded with a hardened upper layer 520 as in FIG. 17B. The upper layer 520 has a hardness of about 0.090 durometers. A ninth embodiment of the extruded cushioning insert 550 has solid main body having a flat upper surface 572 and a wavy lower surface 584 as in FIG. 17C. The insert 550 has a thickness of about 0.03 inch at the troughs of the waves, and about 0.13 inch at the crests of the waves. The insoles 500 and 550 are preferably made of FPVC plastic having characteristics similar to insole 150, and available in pellet form from PolyOne Corporation of Avon Lake, Ohio under its “Geon” A5500 mark.
In an tenth embodiment, the extruded cushioning insert 600 has a main body 610 with opposed upper and lower surfaces 672 and 674 as in FIG. 18. The insert 600 has a width of about 4 inch from side to side. The upper surface 672 is flat and the lower surface 674 is bowed or convex. The solid side portions 612 of the insert 600 have a thickness of about 0.16 inch, and an expanded or divided middle portion 615 has a thickness of about 0.28 inch. The divided middle portion 615 includes a thicker flexible pad 620 with a thickness of about 0.13 inch, and a thinner arcuate wall 630 with a thickness of about 0.03 inch. The pad 620 and arcuate wall 630 are separated by thin deformable walls 683 having a thickness of about 0.025-0.030 inch to from a collapsible chamber 690. The deformable walls 683 divide the chamber 690 into three compartments 691, 692 and 693. The chambers 691-693 are aligned in side-by-side relation so that their upper and lower surfaces 696 and 697, although slightly curved, are generally linearly aligned. The chambers 691-693 are shaped to so as to form a “disc” shape having a combined width of about 2.8 inch. The outer chambers 691 and 693 are “wedged” shaped, with each being a mirror image of the other. The middle chamber 692 has a generally rectangular shape and a width of about 0.78 inch. When compressed, the air in the chambers 691-693 is pushed out the vent ends of the insert 600 and the chambers collapse. The deformable walls 683 also collapse. When the insert 600 is in its compressed position, the upper and lower surfaces 696 and 697 come together and abut each other. The lower surface 674 is substantially flat and parallel to the upper surface 672 of the insert 600. Insole 600 is preferably made of FPVC plastic having characteristics similar to insole 50 or 150, and available in pellet form from PolyOne Corporation of Avon Lake, Ohio under its “Geon” A5500 or B7500 marks.
While the invention has been described with reference to several preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the broader aspects of the invention.

Claims

1. An extruded cushioning insole for footwear to provide cushioning for a human foot with a bottom surface when a placing weight on that foot, the footwear having a sole and an upper that forms the sidewalls of the footwear, said extruded cushioning insole comprising:

a flexible pad having substantially planar and parallel upper and lower surfaces and a perimeter, said pad having a substantially uniform thickness of about 0.06 inch, said perimeter being shaped to supportingly receive the entire bottom surface of the human foot;

a plurality of resilient tubes extending from said lower surface of said pad, said tubes being substantially parallel, uniformly spaced and extending continuously along said lower surface of said pad, each of said tubes having a deformable wall forming a channel with opposed ends;

said pad and tubes being integrally extruded from flexible PVC plastic to form a cushioning insole with a single piece construction, said cushioning insole having a perimeter adapted for placement inside the footwear, said tubes resting on the sole of the footwear and said perimeter of said insole engaging the sidewalls of the footwear to longitudinally and laterally align said insole within the footwear, said tubes and deformable wall being moveable between extended and compressed positions, said flexible pad substantially conforming to the shape of the bottom surface of the foot when in said compressed position; and,

wherein said cushioning insole distributes static forces more evenly across the bottom surface of the foot when in said compressed position, and reduces dynamic forces between the foot and the footwear when placing weight on the foot to move said insole from said extended position to said compressed position, said tubes being resiliently biased to return to said extended position within about 0.25 second when the weight is removed from the foot and insole, said insole resiliently and fully returning to said extended position from said compressed position during the normal life of the footwear.

2. The extruded cushioning insole of claim 1, and wherein each of said deformable walls extends directly from said lower surface of said flexible pad.

3. The extruded cushioning insole of claim 2, and wherein each of said channels is filled with ambient air.

4. The extruded cushioning insole of claim 3, and wherein said deformable wall of each of said tubes includes spaced side wall portions joined by a bottom wall portion, said bottom wall portion being spaced from said lower surface of said pad to form said open channel.

5. The extruded cushioning insole of claim 4, and wherein each of said tubes is spaced apart from its adjacent tube.

6. The extruded cushioning insole of claim 5, and wherein each of said tubes is spaced apart from its adjacent tubes about 0.18 inch, has a height of about 0.25 inch and a width of about 0.38 inch, and said deformable wall has a thickness of about 0.05 inch, and said flexible PVC plastic has a Clash-Berg modulus of rigidity of about 18,000 psi.

7. The extruded cushioning insole of claim 6, and wherein each of said tubes retains an air gap between its said bottom wall portion and said pad when in said compressed position and supporting a 300 pound person.

8. The extruded cushioning insole of claim 4, and wherein adjacent tubes share a common side wall portion.

9. The extruded cushioning insole of claim 8, and wherein said bottom wall portion is arcuate when said insole is in said extended position.

10. The extruded cushioning insole of claim 9, and wherein said pad has a thickness of 0.03 inch, and each of said tubes has a height of about 0.15 inch and a width of about 0.22 inch, and said deformable wall has a thickness of about 0.03 inch, and aid flexible PVC plastic has a Clash-Berg modulus of rigidity of about 1,000 psi.

11. The extruded cushioning insole of claim 8, and wherein said bottom wall portion is flat when said insole is in said extended position, and said flat bottom wall portions combine to form a flexible lower layer parallel to said flexible pad.

12. The extruded cushioning insole of claim 3, and wherein said deformable wall forms a substantially circular tube with a substantially circular cross-sectional shape.

13. The extruded cushioning insole of claim 1, and wherein said upper surface of said pad has a hardness of about 55 to 75 durometers.

14. The extruded cushioning insole of claim 1, and further comprising a separate arch support portion, said cushioning insole and said arch support having spaced apart tubes and matching cross-sectional shapes, said arch support being inverted with its tubes matingly receiving said tubes of said cushioning insole.

15. The extruded cushioning insole of claim 1, and wherein an interior area of said extruded cushioning insole is removed to reduce pressure on the foot in that said interior area.

16. The extruded cushioning insole of claim 1, and wherein said upper surface of said pad has upwardly extending gripping ridges, and is moisture and odor resistant.

17. The extruded cushioning insole of claim 1, and wherein said extruded cushioning insole has demarcations for trimming said perimeter to adapt said insole to fit snuggly inside the footwear.

18. An extruded cushioning insole for footwear to provide cushioning for a human foot with a bottom surface when a placing weight on that foot, the footwear having a sole and an upper that forms the sidewalls of the footwear, said extruded cushioning insole comprising:

a flexible pad having a main body, a planar upper surface, a contoured lower surface and a perimeter, said main body having toe, ball, arch, rearward, and heel regions, and said perimeter being shaped to supportingly receive the entire bottom surface of the human foot;

said toe and rearward regions being formed by said main body, and each having a substantially uniform thickness of about 0.18 inch;

said arch region having a first built up portion extending from said main body, said arch region having a substantially uniform thickness of about 0.28 inch;

said heel region having a second built up portion extending from said main body, said heel region having a substantially uniform thickness of about 0.24 inch;

said main body and said first and second built up portions being integrally extruded from flexible PVC plastic to form a cushioning insole with a single piece construction, said perimeter adapted for placement inside the footwear to engage the sidewalls of the footwear to longitudinally and laterally align said insole within the footwear, said insole being moveable between at rest and compressed positions, said flexible pad substantially conforming to the shape of the bottom surface of the foot when in said compressed position; and,

wherein said cushioning insole distributes static forces more evenly across the bottom surface of the foot when in said compressed position, and reduces dynamic forces between the foot and the footwear when placing weight on the foot to move said insole from said at rest position to said compressed position, said cushioning insole being resiliently biased to return to said at rest position within about 0.25 second when the weight of the foot is removed from the insole, said insole resiliently and fully returning to said extended position from said compressed position during the normal life of the footwear.

19. The extruded cushioning insole of claim 18, and wherein said FPVC plastic has a Clash-Berg modulus of rigidity of about 1,000 psi.

20. The extruded cushioning insole of claim 19, and wherein said ball of foot region has a third built up portion extending from said main body, said built up portion of said ball of foot region being sloped between said arch and toe regions.

21. The extruded cushioning insole of claim 19, and wherein said upper surface of said pad has a hardness of about 55 to 75 durometers.

22. The extruded cushioning insole of claim 21, and wherein said upper surface of said pad has upwardly extending gripping ridges.

23. The extruded cushioning insole of claim 18, and wherein said extruded cushioning insole has demarcations for trimming said perimeter to adapt said insole to fit snuggly inside the footwear.

24. The extruded cushioning insole of claim 18, and wherein an interior area of said extruded cushioning insole is removed to reduce pressure on the foot in that said interior area.

25. An insole extrusion and forming process for making an integral, plastic insole for placing within footwear for a human foot having a bottom surface, the footwear having a sole and an upper that forms the sidewalls of the footwear, said insole extrusion and forming process consisting of the following steps:

providing an extruder, cooling bath, puller, punch press and wind-up roller, said extruder having a material loading trough and a die;

loading FPVC plastic into said trough of said extruder;

heating said FPVC plastic to molten condition;

extruding said molten FPVC plastic through said die, said molten FPVC plastic having a die exit temperature of about 380° F., and said molten plastic forming an extruded web as it exits said die;

pulling said extruded web via said puller through said cooling bath to cool said extruded web to about 150° F. to form a semi-solid, integrally extruded sheet;

cutting integral plastic insoles from said semi-solid, integrally extruded sheet via a punch press, said punch press cutting said insoles from an interior portion of said integrally extruded sheet to leave excess trim in the form of a continuous sheet that maintains its pullable condition; and,

winding up said continuous sheet of excess trim material via a wind-up roller.

26. The insole extrusion and forming process of claim 25, and wherein said extruder includes a barrel and screw and a gate, said barrel and screw continuously pushing and heating the molten FPVC plastic to a temperature of about 370-380° F., and said molten FPVC plastic being heated to a temperature of about 380° F. at said gate.

27. The insole extrusion and forming process of claim 26, and wherein said extruded web is continuously extruded from said die at a speed of about 4 to 6 feet per minute, and continuously moves through said cooling bath and punch press, and around said wind-up roller.

28. The insole extrusion and forming process of claim 27, and wherein said die has a thickness of about 1¾ inch.