Patent Application
20060277786
This application is related to U.S. Patent Application No.______/______, attorney docket number TIMBER 3.0-021 I, filed concurrently herewith and entitled “CHIMNEY STRUCTURES FOR FOOTWEAR AND FOOT COVERINGS,” and U.S. Patent Application No.______/______, attorney docket number TIMBER 3.0-021 II, filed concurrently herewith and entitled “CHIMNEY STRUCTURES FOR FOOTWEAR,” the entire disclosures of which are hereby expressly incorporated by reference herein.
The present invention relates generally to footwear. More particularly, the present invention relates to methods and structures for removing heat, odors, and/or moisture from an article of footwear such as a shoe or a boot.
As is well known, feet generate heat like other body parts. When feet are enclosed in shoes, for example, the shoes tend to retain the heat, which causes the feet to sweat. Sweat or perspiration is a mechanism for the body to flush wastes, regulate body temperature, and help keep the skin clean and pliant. Sweating can be a response to hard working muscles, a hot environment, or over stimulated nerves. It is the evaporation of perspiration from the skin that is the means of heat transfer. Because evaporative heat loss is the major mechanism of cooling, the body is constantly sweating as heat is transferred away from the core to the skin's surface. This is also referred to as insensible water loss, and is so named because it usually goes unnoticed. Insensible water loss, occurring via respiration and the skin (trans-epithelial) cannot be prevented, is a major source of heat loss for the body, and is not controlled by the body's regulatory system.
Eccrine sweat glands are the most numerous type of sweat glands and are found all over the body. They are particularly concentrated in the palms of the hands, soles of the feet and the forehead. There are approximately 250,000 sweat glands in a pair of feet. This represents more sweat glands per square inch of skin than any other part of the body. On average, sweat glands in the feet excrete as much as a half-pint of moisture a day. Moisture (also referred to herein as moisture vapor) includes a liquid that is diffused or condensed in relatively small quantity and dispersed through a gas as invisible vapor. Although sweat's main function is to control body temperature by evaporation, it also serves to keep the skin moist. As such, the skin covering the foot can withstand the constant flexing and friction that happens with locomotion, preventing the skin from rapidly becoming dry, irritated, and uncomfortable.
In the footwear industry the ‘in shoe’ experience of the foot is often referred to as the microclimate of the foot-so called due to the environment that is created when a foot is covered, even partially, by footwear. This zone includes the air trapped by footwear underneath and around the foot. When the footwear substantially covers the foot or just covers the forefoot, and especially if the entire foot is covered in a traditional shoe, boot or like type of footwear, the foot microclimate is a factor in both foot comfort and foot health. The feet experience the highs and lows of temperature and humidity with greater variation than elsewhere on the surface of the body. In part, this is because the feet are further from the heart than any other part of the body. Consequently, by the time the blood arrives to the feet, there has already been considerable cooling.
The core temperature of the body varies only slightly with large changes in environmental temperature, but there is a much greater effect on the feet. For example, with an air temperature of sixty-eight degrees, the surface temp of the foot at rest, without covering (protection) is approximately seventy-two degrees while the core body temperature remains constant at approximately ninety-eight degrees. In this instance, it is necessary to provide thermal insulation to the foot in order to maintain a comfortable foot temperature. Providing a waterproof barrier can also be extremely important feature of footwear in a wet environment as cold water temperatures and the resulting evaporative heat loss can leave the feet very cold and uncomfortable. In extreme situations, this can lead to frostbite and other deleterious conditions.
In the opposite environment, requirements for protective and other footwear are quite different. During activity in hot environments, foot temperature becomes elevated and the humidity within the shoe increases sharply. Of course, materials used in the upper and in the sock will affect both the in-shoe temperature and humidity. Materials that form a barrier to air permeability and water vapor transmission quickly create moist, hot, uncomfortable environments as evaporation of sweat is severely limited, as is air movement within the shoe microclimate. This can also result in an undesirable, malodorous condition.
In warm environments, most protective footwear creates an uncomfortable micro environment, and only the most breathable footwear can provide reasonable comfort for the wearer. A major factor that influences the rate of evaporation is the relative humidity of the air around the foot. If the air is humid, then it already has water vapor in it, probably near saturation, and cannot take any more. Therefore, sweat does not evaporate and cool the body as efficiently as when the air is dry.
Moist, hot air commonly creates a very uncomfortable experience for the foot. This is generally regarded as a compromise in footwear between protection and comfort. An ideal shoe would provide all the needed protection without reducing air flow around the foot. More ideally, air flow should be limited when the foot is cool and increased as foot temperature increases.
Two dynamic factors heavily influence footwear comfort, namely the external environment and the internal environment or microclimate. Protection from the external environment is important for several reasons, including protection from ground level objects or surfaces, moving objects and external climate (temperature and weather conditions). Protection may be provided through design and/or use of materials having characteristics such as insulation, durability, waterproofing and breathability.
Typically, the type of footwear (sandal, work boot, hiker, casual, golf shoe, running shoe, sneaker, etc.) is chosen based on intended use and climate considerations. For example, a runner would likely choose an insulated, waterproof running shoe during cold, wet weather and a light, breathable shoe for use in warm weather. A hiking shoe is commonly chosen for protection from objects in the hiking environment and external climate. Regulation of the footwear's internal environment is extremely important in order to provide a consistently comfortable micro environment as external and internal conditions change during activity. The internal environment is heavily influenced by heat and sweat produced by the body, which, as discussed above, is a method of controlling body temperature.
It is well known that a critical problem with protective and/or enclosed footwear is that moisture vapor from perspiration is trapped and cannot escape the footwear. In order to provide increased comfort, wicking characteristics have been applied to sock and liner materials. At least some of the moisture is absorbed within the footwear, the sock and/or the liner materials. Once such materials become saturated they can loose their effectiveness and create an unpleasant environment for the foot.
Such materials can quickly reach a saturation point as the moisture within the shoe typically does not have an efficient method of evaporation. Skin also absorbs moisture when in a saturated environment. Skin is softened by the absorbed moisture, becomes more sensitive to pressure, and also becomes prone to abrasion and fungal infection. Thus, the reduction in airflow around the foot and within an article of footwear presents a significant number of challenges to creating a comfortable environment for the foot.
Another consideration is that although there have been advances in materials that claim a level of breathability or airflow through (stand alone) material, testing has proven that when such materials are combined with traditional constructions of protective footwear, the breathability is greatly reduced due to construction types and the necessity of the materials to be used in combination with additional ‘non-breathable’ materials and adhesives during the construction process. Therefore, a need exists for advanced footwear and foot covering materials and methods of manufacture that enhance air flow and convective cooling of the foot while providing comfort, support and other common features of footwear.
In accordance with one embodiment of the present invention, an article of footwear is provided. The article of footwear comprises an outsole, an upper, and a chimney structure. The upper is attached to the outsole and defines a cavity for receiving a wearer's foot. The chimney structure comprises a plurality of chimneys defining pathways for moving heat or moisture from within the cavity to outside the article of footwear.
In one alternative, the chimney structure is disposed along a side panel of the upper. In another alternative, the chimney structure comprises a plurality of channels arranged in a row along the upper.
In a further alternative, the chimney structure comprises two rows of chimneys adjacent to one another. Here, the pathways of a first one of the rows face the cavity and the pathways of a second one of the rows face away from the cavity. In this case, the first row is preferably adjacent to a wearer's foot and the second row is preferably adjacent to the outside of the article of footwear. Optionally, each of the chimneys of the first row shares a common wall with a corresponding one of the chimneys of the second row. In this case, the common wall preferably includes at least one opening therein to enable the heat or moisture to pass from one of the pathways in the first row to one of the pathways in the second row.
In yet another alternative, the upper includes a collar and a body connected to the collar. The body defines the cavity and the collar providing an opening to the cavity. Selected pathways of at least some of the chimneys each have a first end disposed along the upper below the collar and a second end disposed along the collar. In this case, the first end of each selected pathway is preferably positioned at or below ankle height. Here, the first end of each selected pathway is desirably located to be adjacent to the bottom of foot. In yet another alternative, the movement of heat or moisture occurs by convection.
In accordance with another embodiment of the present invention, a chimney structure for convection of heat or moisture out of the microclimate of an article of footwear is provided. The chimney structure comprises a plurality of chimneys. Each of the chimneys includes a first end open to receive the heat or moisture from an interior of the article of footwear and a second end open to move the heat or moisture from within the interior to outside the article of footwear.
In one example, the chimneys are removably insertable into the article of footwear. In another example, the chimneys are integrally formed in the article of footwear.
In one alternative, each of the chimneys includes first and second sidewalls and an endwall connecting the first and second sidewalls. The sidewalls and the endwall define a pathway between the first and second ends of the chimney. In another alternative, each of the chimneys has a cross-sectional area of at least 16 mm2. In a further alternative, the chimney structure comprises molded fabric with poured polyurethane. In yet another alternative, the chimneys have a hardness of at least 15 Asker C.
In accordance with a further embodiment of the present invention, an article of footwear is provided. The article of footwear comprises an outsole and an upper attached to the outsole. The upper includes an outer material defining a cavity for receiving a wearer's foot and a collar region for insertion of the wearer's foot into the cavity. The article of footwear also comprises a plurality of chimneys arranged in a row along an interior side of the outer material for moving heat or moisture from within the cavity to outside the article of footwear.
In one alternative, the article of footwear further comprises a plurality of elongated vents formed by overlapping sections of the outer material. The plurality of elongated vents intersect with the plurality of chimneys to promote movement of the heat or moisture from within the cavity to outside the article of footwear. In this case, at least one of plurality of the elongated vents preferably intersects the row of chimneys at an angle between 15° and 75°, whereby venting of the heat and moisture is enhanced. In another example, the article of footwear further includes a footbed having a porous chassis operable to permit airflow from underneath the wearer's foot into the row of chimneys.
In accordance with yet another embodiment of the present invention, an article of footwear is provided. The article of footwear comprises an outsole and an upper attached to the outsole. The upper defines a cavity for receiving a wearer's foot and includes a tongue. The article of footwear also includes a chimney structure comprising means for moving heat or moisture from within the cavity to outside the article of footwear. Desirably, moving the heat or moisture occurs by convection. Preferably the chimney structure is disposed along the tongue.
The tongue chimney structure desirably comprises a chimney having a pair of sidewalls and an endwall connecting the sidewalls. Here, the chimney may have a first opening at a toe region of the upper and a second opening along an upper portion of the tongue, whereby heat and moisture are vented out from the toe region. Alternatively, the chimney mayhave a first opening at an instep region of the upper and a second opening along an upper portion of the tongue, whereby heat and moisture are vented out from the instep region.
The tongue chimney structure preferably comprises a row of chimneys. Alternatively, the chimney structure comprises two rows of chimneys adjacent to one another. In this case, a first one of the rows faces the cavity and a second one of the rows faces away from the cavity. Here, at least some of the chimneys of the first row preferably share a common wall with corresponding chimneys of the second row. Preferably, the common wall includes at least one opening therein to enable the heat and/or moisture to pass from one of the chimneys in the first row to one of the chimneys in the second row. In another alternative, the chimney structure is removably insertable in the tongue.
In accordance with yet another embodiment of the present invention, an article of footwear is provided. The article of footwear comprises an outsole, an upper and a chimney. The upper is attached to the outsole and defines a cavity for receiving a wearer's foot and including a tongue. The chimney is disposed in the tongue to enable movement of heat and moisture from within the cavity to outside the article of footwear.
In one example, the chimney has a substantially semicircular cross-sectional shape. In another example, the chimney has a substantially rectangular cross-sectional shape. In a further example, the chimney comprises a flexible material, whereby the chimney flexes in response to movement by a wearer. In yet another example, the movement of the heat or moisture occurs by convection.
In accordance with another embodiment of the present invention, a chimney structure for ventilating the microclimate of article of footwear is provided. The article of footwear includes a tongue. The chimney structure comprises a chimney disposed in the tongue to move heat or moisture from within an interior region of the article of footwear to outside the article of footwear. The chimney includes a pair of sidewalls and an endwall disposed between the pair of sidewalls. The sidewalls and the endwall define a pathway therealong. The heat or moisture is moved through the pathway from the interior region to outside the article of footwear.
In one alternative, the chimney structure further comprises a wicking material covering at least a portion of the chimney. The wicking material draws the moisture away from the wearer's skin. In this alternative, the chimney structure desirably further comprises a waterproof membrane. The wicking material covers an interior surface of the chimney facing the interior region of the article of footwear and the waterproof membrane covers an exterior surface of the chimney. Here, the waterproof member may include one or more openings to promote venting of the heat or moisture out of the pathway.
In another alternative, the chimney structure further comprises a covering substantially enclosing the chimney. The covering includes a pocket for storing laces of the article of footwear. In yet another alternative, the chimney structure further comprises a cushioning material disposed at a top region of the chimney structure facing the interior region of the article of footwear.
In accordance with another embodiment of the present invention, a form fitting foot covering is provided. The foot covering includes a heel region, a toe region, and a sole region disposed between the heel region and the toe region. It also includes a collar region providing an opening for insertion of a wearer's foot into the heel, toe and sole regions of the foot covering, as well as a chimney structure comprising a chimney for moving heat or moisture from within the foot covering out of the collar.
In an alternative, the chimney structure comprises a plurality of chimneys. Each of the chimneys includes a pair of elongated supports and braces connecting the pair of elongated supports. In this case, the foot covering preferably further comprises a covering disposed on a first side of the pair of elongated supports. Here, the covering desirably includes a pair of coverings. The first covering is disposed on the first side of the pair of elongated supports and the second covering is disposed on a second side of the pair of elongated supports opposite the first side. Optionally, the first covering is positioned for direct contact with the wearer's foot and comprises a wicking material.
In another alternative, each of the chimneys is flexible and the braces are movable from an at-rest position to a stretched position or a compressed position as the foot moves. In this case, the braces are preferably positioned in the at-rest position at a predetermined angle relative to the elongated supports. Desirably the predetermined angle is at least 15 degrees. In a further alternative, moving the heat or moisture occurs by convection.
In accordance with yet another embodiment of the present invention, a foot covering adapted for covering a wearer's foot comprises a body, a collar, a plurality of chimneys and a skirt section. The body has a heel region, a toe region, and a sole region disposed between the heel region and the toe region. The collar region is connected to the body for insertion of a wearer's foot into body. The plurality of chimneys provide movement of heat or moisture from within the body out of the collar. The skirt section is formed at the connection of the body and the collar. The skirt section is adapted to prevent debris from entering a shoe when the foot covering is positioned therein.
In an example, the skirt section is positioned at ankle height. In another example, the skirt section includes a pocket to receive the laces of the shoe. In this case, the pocket may comprise a stretchable material.
In an alternative, the chimneys each include a first opening in the body and a second opening in the collar region, whereby heat or moisture enter the chimneys at the first opening and exit at the second opening. In one example, at least some of the first openings are disposed in the toe region. In another example, at least some of the first openings are disposed in the heel region. In a further example, at least some of the first openings are disposed in the sole region. Optionally, the plurality of chimneys comprises a chimney structure that at least partly surrounds the toes of the foot during wear.
In accordance with another embodiment of the present invention, a ventilated article of clothing is provided. The ventilated article of clothing comprises a covering for enclosing a portion of a wearer's body, and a chimney structure. The chimney structure includes a plurality of chimneys that vent heat or moisture by convection from a first region within the covering to a second region outside of the covering. In one example, the article of clothing comprises a sock. In another example, the article of clothing comprises a glove.
FIGS. 1(a)-(b) illustrate an exemplary shoe in accordance with aspects of the present invention.
FIGS. 2(a)-(h) illustrate chimney structures in accordance with aspects of the present invention.
FIGS. 3(a)-(d) illustrate alternative chimney structures in accordance with aspects of the present invention.
FIGS. 4(a)-(g) illustrate additional chimney structures in accordance with aspects of the present invention.
FIGS. 5(a)-(e) illustrate further chimney structures in accordance with aspects of the present invention.
FIGS. 7(a)-(g) illustrate an alternative boot utilizing chimneys in accordance with aspects of the present invention.
FIGS. 8(a)-(e) illustrate another boot utilizing chimneys in accordance with aspects of the present invention.
FIGS. 9(a)-(h) illustrate yet another boot utilizing chimneys in accordance with aspects of the present invention.
FIGS. 10(a)-(c) illustrate an alternative chimney structure in accordance with aspects of the present invention.
FIGS. 12(a)-(j) illustrate further chimney structures in accordance with aspects of the present invention.
FIGS. 13(a)-(e) illustrate a sock utilizing chimneys in accordance with aspects of the present invention.
FIGS. 14(a)-(e) illustrate exemplary chimney structures in accordance with an aspect of the present invention.
FIGS. 15(a)-(e) illustrate a footbed in accordance with aspects of the present invention.
In describing the preferred embodiments of the invention illustrated in the appended drawings, specific terminology will be used for the sake of clarity. However, the invention is not intended to be limited to the specific terms used, and it is to be understood that each specific term includes equivalents that operate in a similar manner to accomplish a similar purpose. By way of example only, the term “footwear” is used herein to include, without limitation, all manner of foot coverings such as boots, shoes, sandals, athletic sneakers, loafers etc.
Both experience and research illustrate the need to preferentially handle heat and moisture removal from footwear. The inventors of the present invention conducted live trials using volunteer subjects to evaluate how airflow in the shoe microclimate affects heat and moisture retention, and, ultimately, shoe comfort. A first testing phase focused on climate control and moisture management within a hiking shoe structure. Human subjects were asked to evaluate four different hiking shoes having different upper constructions.
The first hiking shoe included an all mesh upper designed for maximum breathability. The second hiking shoe included a mesh upper with a waterproof membrane capable of venting moisture designed for average breathability. The third hiking shoe was a conventional off-the-shelf hiking shoe including an integral waterproof membrane capable of venting moisture designed for average breathability. The fourth hiking shoe included a mesh upper having a polyurethane (“PU”) lining designed for minimum breathability. Table 1 provided below compares the four shoe structures.
Ten subjects tested each of the four shoes. For each test, the subject wore a pair of thin socks having the composition 42% cotton, 14.5% spandex, 21.5% nylon, and 22% polyester. Each test included a warm-up period, a test period, and a cool down period. During the warm-up period the subject wore his or her own shoes. After warm-up, the subject walked on a treadmill for a period of 15 minutes at a speed of 4mph. Shoe weight and sock weight were recorded before and after the 15 minute walking period. At the conclusion of the test the subject stepped off of the treadmill and was allowed a five minute cool down period. Each subject wore a fresh pair of socks for each shoe tested.
During the 15 minute walking period the temperature of the foot was monitored with a thermocouple mounted in the location of the in-step. While walking, the subjects were asked a series of questions pertaining to the microclimate of the shoes being worn. Subjects answered the questions by evaluating aspects of the microclimate on a scale of one through three, including temperature and humidity. A description of this rating scale can be found in Table 2.
Immediately after stepping off the treadmill, the left shoe was removed and internal shoe temperature and humidity measurements were taken. Shoe and sock weights were also measured (in grams) and recorded. The test results are in Table 3.
The test results presented in Table 3 demonstrate the wearers' perception of comfort as it relates to moisture retention around the foot. Wearers perceived the all mesh upper of shoe one as being the coolest and driest after the test. The production shoe was perceived as being the hottest and most damp shoe after the test. The column entitled “ΔT” pertains to the increase in temperature during the trial and supports the wearers' assessments as to heat retention by the shoes. The time in the ΔT column runs from when the wearer initially placed his or her foot in the shoe to the end of the test after the cool down period. Here, the smallest temperature increase occurred in the all mesh upper, and the largest temperature increase occurred in the production shoe. The columns entitled “Sock Weight Gain” and “Shoe Weight Gain Including Footbed” provide statistical data confirming the wearers' assessments as to how much moisture was retained within the sock and the shoe. The all mesh upper caused the least amount of moisture to be retained in the sock and in the shoe itself. The production shoe caused the most moisture to be retained in the sock and in the shoe.
Table 4 illustrates a ranking of the four shoe structures based upon the subjective ratings by the test subjects. The rankings ranged from 1 to 4, with 1 being the best performance among all of the shoes and 4 being the poorest performance among all of the shoes.
As seen by the results of Table 4, the all mesh upper of the first shoe had the highest performance ranking among all of the shoes in all of the categories, whereas the conventional production shoe had the worst, or a tie for the worst, ranking in each category. As seen in the mean foot temperature column, the mesh upper with the PU lining was ranked the same as the production shoe.
The inventors of the present invention also conducted laboratory tests separate from the human trials to evaluate how airflow in the shoe microclimate affects heat and moisture retention. The same four shoe structures used in the human trials were tested in the laboratory. Testing was conducted using standards developed by the SATRA Technology Centre.
Specifically, advanced moisture management testing using the SATRA Advanced Moisture Management (“AMM”) test was conducted using the four hiking shoe structures discussed above. Testing simulated the generation of heat and sweat by the foot in a shoe, quantifying the distribution of sweat output by absorption, evaporation loss, and energy usage, as will be explained below.
Testing was conducted under laboratory conditions of 20° C. and 65% relative humidity. A simulated foot was used to conduct the test. The simulated foot was covered in a simulated skin membrane. A sock was then placed on foot and inserted into one of the four test shoe structures. The sock had the same composition as in the human trials. The simulated foot was maintained at a temperature of 34° C. with a nominal sweat rate of 5 mL/hr.
The sweat rate was controlled in a closed loop such that the only means of egress was into the footwear being tested. A constant airspeed of 2 m/s was maintained across the shoe during the test. The mass of water input to the system in each test was approximately 13.5 g±0.3 g. Once the system was brought to equilibrium, the test lasted for a period of 180 minutes. The results of the test indicated the amount of moisture retained in the simulated skin, the sock, the footbed, and the shoe itself, as well as the evaporated mass of water and the amount of energy required to maintain the foot at 34° C. A low thermal energy input value would indicate a high degree of thermal insulation within the shoe. The laboratory test results are shown in Table 5.
As seen by the results in Table 5, the all mesh upper of the first shoe had the least amount of moisture gain in the simulated skin membrane of the foot, in the sock, in the footbed by itself, and in the shoe including the footbed. The shoe with the all mesh upper also had a much greater amount of evaporative moisture loss than any of the other shoes tested. The evaporation results correlate with the data for thermal energy input as shown in the rightmost column. Here, the all mesh upper required the most amount of input energy to maintain the simulated foot at a temperature of 34° C.
Table 6 illustrates a ranking of the four shoe structures based upon the objective test results from the laboratory experiments. As with the rankings of Table 4, the rankings in Table 6 range from 1 to 4, with 1 being the best performance among all of the shoes and 4 being the poorest performance among all of the shoes.
As seen by the results of Table 6, the all mesh upper of the first shoe had the highest performance ranking among all of the shoes in all of the categories, whereas the conventional production shoe had the worst ranking in most of the categories. While the production shoe had the second best ranking in the column labeled “Footbed Gain Only,” it ranked the lowest in four of the six total categories.
At the conclusion of the laboratory AMM testing, the laboratory results were compared with those obtained from the human trials to look for correlation. The assumption is that a high degree of correlation between the human and laboratory tests allows for the assessment of the moisture management properties of subsequent footwear designs using laboratory tests only, without the need for conducting many expensive and time consuming human trials.
The laboratory tests and human trials were compared for two criteria, moisture and heat. In a first comparison with regard to moisture, the average subjective humidity ratings in the human trials were compared to the average evaporated loss in the laboratory tests. In a second comparison with regard to heat, the average subjective temperature ratings in the human trials were compared to the average energy used in the laboratory tests.
The data were compared using a regression analysis technique involving the coefficient of determination (“R2”), which is a well known and often used statistical analysis tool. The coefficient of determination is a measure of the correlation between the two variables in the regression analysis. Here, the variables were either the average subjective humidity as compared to the averaged evaporated loss, or the average subjective temperature as compared to the average energy used. The R2 value ranges between 0 and 1. A 0 value indicates no correlation, and a 1 value indicates strong correlation. The R2 value in the moisture comparison was 0.9077. The R2 value in the heat comparison was 0.8899. Thus, it can be seen that the human and laboratory test results are highly correlated.
The analysis also involved a statistical examination as to the interdependence of the variables from the human and laboratory tests. This involved calculating a correlation coefficient (“r”), which is expresses as r=√R2. The correlation coefficient may range from −1 to 1. As with the coefficient of determination, it is desirable for the correlation coefficient to be as close to 1 as possible. The r value in the moisture comparison was 0.95. The r value in the heat comparison was 0.94. Thus, the correlation coefficients in both analyses confirm that the human and laboratory tests are highly correlated. Therefore, footwear that performs well in laboratory testing should be more than acceptable to actual wearers. In particular, footwear configurations that lower moisture absorption in the sock, in the shoe, and/or in the footbed or sockliner should have a perceptibly drier fee. Footwear configurations that have a higher thermal energy input should have a perceptibly cooler feel.
In addition to the human and laboratory testing discussed above, research demonstrates that the movement of air (airflow), as exemplified by convection, enhances the evaporation transfer of heat by the movement of air from a hot region to a cool region. By creating an environment around the foot that allows for airflow, such as by convective transport, of heat or moisture away from the skin and out of the shoe, the foot will be kept drier and more comfortable. Convention, or convective transport, is a passive process that does not require an active mechanical action. While the terms heat and moisture are referred to in the alternative, it should be understood that this also includes airflow of both heat and moisture together. Evaporation of moisture facilitates cooling, improves functional performance, and reduces the likelihood of a foot-related injury—especially those related directly to the skin such as abrasion, swelling, and blisters. Proper evaporation also reduces the chance of fungal and skin infections, and reduces malodorous conditions.
In accordance with aspects of the present invention, channel or chimney devices, hereinafter referred to as “chimneys,” can be employed with articles of footwear including shoes, foot coverings such as socks, etc., to provide cooling and to remove moisture away from the foot.
FIGS. 1(a)-(b) illustrate an exemplary shoe 10 suitable for use with chimneys and other ventilation structures in accordance with the present invention. The shoe 10 may be any type of conventional or specialty footwear, including, but not limited to dress shoes, loafers, athletic shoes such as sneakers, work boots, hiking boots, etc. Here, the exemplary shoe is shown having an outsole 12 and an upper 14. The outsole 12 may include a tread 16 on the bottom thereof. As shown, a region 18 connects the outsole 12 to the upper 14. The region 18 may be integral with the outsole 12, or may comprise a separate midsole, a lasting board, etc. Alternatively, the outsole 12 and the upper 14 may be integrally formed as a single piece. Additional features such as a shank piece, arch support, etc. (not shown), may be fixed as part of the shoe 10 or may be removable therefrom.
The upper 14 may include a body 20 as well as a collar or collar region 22, which defines an opening that enables a wearer to insert his or her foot into an interior cavity 24 of the body 20. The body includes sidewalls or side panels of the upper, which may be formed from multiple pieces or as an integral unit. The sidewalls/side panels may also include a heel region. The upper 14 may have a tongue 26, which may be part of the body 20 and which may be attached, at least in part, to the collar or collar region 22. The body 20 may also include fasteners 28, such as laces 28a, eyelets 28b, and/or other structures such as hook and loop fastening straps, snaps, clips, etc. to adjustably and comfortably secure the foot within the shoe 10.
As seen in the top view of
As best seen in FIGS. 2(b) and 2(e), the body chimneys 32 in this example are preferably positioned generally vertically along the body 20 and the collar 22 of the upper 14. Such a configuration promotes efficient migration of heat and/or moisture up from lower regions of the shoe 10. However, the pathways 42 may be arched, angled, curved, s-shaped, etc (see FIGS. 14(a)-(e)). Regardless of specific pathway alignment, the body chimneys 32 are desirably positioned so that some or all of the pathways 42 have a first end 42a disposed along the upper 14 below the collar 22 and a second end 42b at or near the top of the collar 22 to evacuate heat and/or moisture out of the microclimate of the shoe 10. The first end 42a is preferably positioned at or near the foot, more preferably at or below the ankle. While the ankle height differs for different people, the typical ankle height for an adult male is, for instance, less than about seven inches when measured relative the bottom or sole of the foot. Desirably, the first end 42a is placed as close to the footbed or the bottom/sole of the foot as possible. By way of example only, the first end 42a may be placed 1-2 inches or less from the bottom of the foot. More preferably, the opening at the first end 42a is less than one inch from the bottom of the foot. The opening 42a of the first end should be positioned above the insole, if any. However, if a ventilating insole is used, the opening 42a may be placed at the height of the ventilating insole. It is important that the second end 42b or other portion(s) of the pathway 42 higher than the first end 42a be exposed to the external climate to promote effective heat/moisture evacuation.
FIGS. 2(e)-(h) illustrate a set of tongue chimneys 34 in more detail. The tongue chimneys 34 may include structures that are substantially equivalent to the body chimneys 32. For example, as seen on
The central portion 52 of the tongue chimney 34 preferably includes one or more openings 62 and one or more braces 64 therebetween. While not required, the openings 62, if used, act as passageways between the opposing rows of tongue chimneys 34. As seen in FIGS. 2(e) and 2(h), the pathways 54 promote conduction of heat and/or moisture away from the bottom of the upper 14 near the toe and instep regions and toward the upper part of the tongue 26. The openings 62 permit the heat and/or moisture to move between pairs of the tongue chimneys 34. For instance, hot and/or moist air may migrate from the inner row of tongue chimneys 34 out to the exterior row of tongue chimneys 34 via the openings 62.
The tongue chimneys or tongue vents 34 are preferably positioned to promote efficient migration of heat and/or moisture upward away from the front/toe region of the shoe 10. The tongue chimneys 34 are desirably positioned so that each pathway 54 has a first end 68 disposed along the upper 14 in the front/toe region and a second end 70 at or near the top of the tongue 26 to evacuate heat and/or moisture out of the microclimate of the shoe 10. The first end 68 is preferably positioned at or near the toes or the front portion of the foot. It is important that the second end 70 or other portion(s) higher than the first end 68 of the pathway 54 be exposed to the external climate, for instance at or near the top of the tongue 14, to promote effective heat/moisture evacuation.
When a single row of one or more body chimneys or body vents 32 is employed, the opening 44 of each pathway 42 preferably faces inward towards the foot. Similarly, when a single row of one or more tongue chimneys 34 is employed, the opening 56 of each pathway 54 preferably faces inward towards the foot. When a second row of body and/or tongue chimneys 32, 34 is employed, the pathway openings 44, 56 help promote air exchange between the shoe microclimate and the external climate, as seen in FIGS. 2(d) and 2(h).
FIGS. 4(e)-(g) illustrate an alternative wherein one or both sides of the tongue chimney structure 60′ or 60 are covered by a material 80. The material 80 may be permanently or removably attached to the tongue chimney structure 60′ or 60. Preferably, the material 80 comprises a first lining 80a, which faces the wearer's leg during use and a second lining 80b, which faces away from the leg during use. The first lining 80a has one or more layers of material, preferably including at least one layer of wicking material in immediate exposure to the shoe microclimate. Examples of this type of lining include a chemically treated brushed polyester, rayon, nylon, cotton or combination of companion fibers or a specialty woven or knit material used in combination to maximize breathability by absorbing moisture next to the skin and wicking away moisture from the surface of skin to allow for evaporation. Wicking materials sold under the brand names COOLMAX, DRITEX, and POWER DRY are commonly known in the industry. The second lining 80b has one or more layers of material, preferably including at least one layer of non-wicking material, such as a mesh. The mesh could comprise one or more layers of coated nylon, polyester, and/or cotton. The second lining 80b may also include a pocket 82, which may be disposed at or near the top of the lining. The pocket 82 is preferably sized to permit the wearer to store at least a segment of the laces therein. The pocket 82 may be formed of a stretch mesh or other suitable material. For example, the pocket 82 may comprise nylon, synthetic leather, or, preferably, a non woven material with an elongation value of at least 150%.
FIGS. 5(a)-(e) illustrate cross sections of alternative chimney structures suitable for use in alternative embodiments of the present invention.
In
In each of the chimney configurations shown in FIGS. 5(a)-(d), the chimneys are partly or fully open along one side. However, in alternative embodiments for the chimney structures disclosed herein, some or all of the chimneys may be substantially or completely closed on all sides. By way of example only,
While enclosed on all sides, the chimneys 196 preferably include one or more openings 198 in one or both of the walls 192a,b. In body chimney structures such as the body chimney structure 36, the openings 198 are preferably formed at the first and second ends 42a, 42b of the pathways 42. Additional openings 198 may be positioned similar to the openings 46 shown in FIGS. 2(d), (e). Additional openings 198 are particularly suitable when two parallel rows of chimneys 196 are used, such as those described above with respect to FIGS. 2(c) and 3(d). If used, such additional openings 198 may act as passageways between the rows of chimneys 196.
While the chimney structures in the embodiments presented above illustrate multiple chimneys along the body 20 and collar 22 of the upper 14 or along the tongue 26, other embodiments of the present invention contemplate the use of a single chimney, which may be positioned anywhere within the upper 14. Alternatively, one chimney may be positioned adjacent to each side and/or the rear or front of the foot within the upper 14. Here, a first end of the chimney should be open at or near the foot bed region, for instance below ankle level or as close to the bottom of the foot as possible. A second end or portion of the chimney should be open to the external climate.
The chimneys of the present invention may be incorporated into footwear in different ways. For example, body chimneys and/or tongue chimneys may be integral with the upper 14, or may be removably coupled to the upper 14 as separate components. Chimneys can be molded or otherwise inserted into the interior walls of a shoe. While chimneys could be positioned in a number of layers of an article of footwear, it is most preferable to position at least some of the chimneys in one or more layers as close to the foot as possible in order to reduce the distance that heat and moisture generated from the foot have to travel before evacuation via the chimneys. Convective air movement facilitates evaporation and other forms of cooling.
In one example, the chimneys are formed by molding a foam layer and then covering the foam layer with a comfortable lining material. Additional examples of chimney materials are discussed below. Chimneys are desirably constructed of a geometry that provides a sufficient surface against the foot and ankle to prevent discomfort and pinching, for example, from sharp edges and high pressure areas through the reduction of surface area between the foot and shoe.
Because convection is the primary mechanism guiding air movement from inside the microclimate of the shoe to the outside environment, the evacuation of warm, moist air occurs without requiring user intervention or mechanical devices when employing chimneys in accordance with the present invention. Convective currents become more powerful as the relative temperature difference between two objects increases. During low activity, foot temperature and internal shoe temperature remain relatively low. As activity increases, foot temperature and in-shoe temperature can increase very rapidly. The increase in temperature creates a correspondingly increased thermal gradient between the in-shoe microclimate and the external environment, which creates stronger convection currents and greater heat and humidity evacuation from the shoe. Pumps or other mechanical apparatus are thus unnecessary.
The channels discussed above may be implemented in a wide variety of footwear. Several exemplary articles of footwear implementing chimneys are shown and described below. For instance,
The body 210 includes a body chimney structure 220 having multiple chimneys 222 having pathways 224 therein. The body chimney structure 220 is preferably same as the body chimney structure 36, although any chimneys and chimney structures in accordance with the present invention may be employed in the boot 200. The body chimney structure 220 is shown having openings 226 near the ends of the pathways 224 along the collar 212. The body chimney structure 220 may include opposing rows of body chimneys 222 (such as are body chimneys 32a,b of
The portion of the body chimney structure 220 along the collar 212 provides venting to the external climate. Other portions of the body chimney structure 220 are shown being covered by a layer of material 228. The material layer 228 is preferably leather or a leather/fabric combination. This material layer may be substantially non-permeable to heat and/or moisture. In this case, it is particularly desirable for the body chimney structure 220 to include the openings 226 positioned at or near the collar 212 above the material layer 228 to enhance ventilation.
The tongue 214 preferably includes a tongue chimney structure 230. The tongue chimney structure 230 is preferably same as the tongue chimney structure 60 or 60′, although any chimneys and chimney structures in accordance with the present invention may be employed in the boot 200. The exterior of the tongue chimney structure 230 is shown being covered by a material 232, which is preferably the same as the material 80 discussed above with regard to FIGS. 4(e)-(g). A pocket 234 may also be included is also shown as part of the material 232. The pocket 234 is designed to permit the wearer to store the laces 216 therein.
The body 310 includes a body chimney structure 320 having multiple chimneys 322 having pathways 324 therein. The body chimney structure 320 is preferably same as the body chimney structure 220, although any chimneys and chimney structures in accordance with the present invention may be employed with the boot 300. The body chimney structure 320 is shown having openings 326 near the ends of the pathways 324 along the collar 312. As will be described in more detail below, the body chimney structure desirably includes opposing rows of body chimneys 322 (such as the body chimneys 32a,b of
The portion of the body chimney structure 320 along the collar 312 provides venting to the external climate. Other portions of the body chimney structure 320 are shown being covered by a material 328. The material 328 is preferably leather or a leather/fabric combination or any other commonly used material within footwear. This material may be substantially non-permeable to heat and/or moisture. The material 328 desirably includes one or more openings 330. The openings may come in any shape desired, including, but not limited to the substantially triangular, trapezoidal, and oval shapes presented.
The material layer 328 may comprise multiple layers, including a material 334 that is a substantially waterproof membrane. More preferably, the material 334 comprises a substantially waterproof membrane capable of venting moisture from the shoe microclimate to the outside environment. By way of example only, the material 334 may comprise an expanded PTFE material, such as the materials shown and described in U.S. Pat. Nos. 6,108,819, 6,228,477, 6,410,084, 6,676,993, and 6,854,603, the entire disclosures of which are hereby expressly incorporated by reference herein. As seen in
The material layer 328 may also include an exterior structure 336, with the openings 330 therein. The exterior structure 336 may be formed, for example, of PE or any of the commonly used materials in footwear such as leather, synthetic leather or a waterproof version of the same. Overlying the exterior structure 336 there may be a covering 338, such as a highly porous material, e.g., mesh. The covering 338 preferably covers the openings 330 as well as the exterior structure 336.
The tongue 314 preferably includes a tongue chimney structure 340, as shown in the exterior view of
The first row 342a is desirably covered by a material 344, which may comprise a wicking material for removing or pulling moisture away from the wearer's skin and/or away from a sock. The second row 342b is desirably covered by a material 346, which may be a substantially waterproof membrane. More preferably, the material 346 comprises a substantially waterproof membrane capable of venting moisture from the shoe microclimate to the outside environment, such as the material 334 discussed above. The membrane of the material 346 may include a tricot material, such as a monofilament tricot.
Exterior structure 348 preferably overlies the material 346. As seen in
The body 410 includes a body chimney structure 420 having one or more chimneys 422 having pathways 424 therein. The body chimney structure 420 is preferably same as the body chimney structure 220, although any chimneys or chimney structures in accordance with the present invention may be employed with the body 400. The body chimney structure 420 is shown having openings 426 near the ends of the pathways 424 along the collar 412. As will be described in more detail below, the body chimney structure 420 desirably includes opposing rows of body chimneys 422, with one row facing inward towards the wearer's foot and the other row facing in the opposite direction. However, a single row can be used.
The portion of the body chimney structure 420 along the collar 412 provides venting to the external climate. Portions of the body chimney structure 420 are shown being covered by a material 428. The material 428 is preferably leather or a leather/fabric combination, although other materials may be used. The material 428 may be substantially waterproof. The material 428 desirably includes one or more vents 430, which each may include one or more vent holes 430′ thereon.
The material layer 428 may comprise multiple layers, including a material 434 that is a substantially waterproof membrane. More preferably, the material 434 comprises a substantially waterproof membrane capable of venting moisture from the shoe microclimate to the outside environment, as described above with respect to the material 334. By way of example only, the material 434 may comprise expanded polytetrafluroethylene. As seen in
The tongue 414 preferably includes a tongue chimney structure 438, as shown in the exterior view of
The first row 442a is desirably covered by a material 444, which may comprise a wicking material for removing or pulling moisture away from the wearer's skin and/or away from a sock. The second row 442b is desirably covered by a material 446, which may be a substantially waterproof membrane. More preferably, the material 446 comprises a substantially waterproof membrane capable of venting moisture from the shoe microclimate to the outside environment, such as the material 334 discussed above. The membrane of the material 446 may include a tricot material, such as a monofilament tricot.
A covering 448 may optionally overly the material 446. The covering 448 is preferably a non-wicking material that may be the same material as the covering 338 or the covering 354. The covering 448 preferably underlies the openings 440. An outermost material layer 450 overlies the covering 448, the material 446, and the tongue chimney structure 438. The openings 440 are formed in the outermost material layer 450. As can be seen in
A gusset 452 may be attached to the tongue 414 adjacent or near to the end of the tongue chimney structure 438. The gusset 452 may be sewn or otherwise connected at one end thereof to the outermost material layer 450. The other end of the gusset 452 connects the upper 404 to the tongue 414. The connection or attachment to the upper 404 may be at a height up to and including the collar. The gusset 452 may comprise any material, preferably a stretchable material. A lining 454 may be placed behind the gusset 452. The lining 454 preferably comprises a waterproof membrane, with or without a monofilament tricot. In a preferred embodiment, the lining 454 is a continuation of the material 446.
The body 510 includes a body chimney structure 520 having one or more chimneys 522 having pathways 524 therein. The body chimney structure 520 is preferably same as the body chimney structure 220 described above, although any chimneys and chimney structures in accordance with the present invention may be employed. The body chimney structure 520 is shown having openings 526 near the ends of the pathways 524 along the collar 512. As will be described in more detail below, the body chimney structure desirably includes opposing rows of body chimneys 522, with one row facing inward towards the wearer's foot and the other row facing in the opposite direction. A single chimney or row of chimneys can also be used.
The portion of the body chimney structure 520 along the collar 512 provides venting to the external climate. Portions of the body chimney structure 520 are shown being covered by a material 528. The material 528 preferably comprises PE, although other materials may be used. The material 528 desirably includes one or more openings 530. The openings may come in any shape desired, including, but not limited to the substantially triangular, trapezoidal, and oval shapes presented.
The material 528 may comprise multiple layers; however, unlike the material 328 of
The tongue 514 preferably includes a tongue chimney structure 536, as shown in the exterior view of
The first row 538a is desirably covered by a material 540, which may comprise a wicking material for removing or pulling moisture away from the wearer's skin and/or away from a sock. As with the body 510 of the upper 504, the tongue 514 need not covered by a waterproof membrane. Instead, an exterior structure 542 preferably overlies the tongue chimney structure 536. As seen in
FIGS. 9(e)-(h) illustrate alternative placement of the body chimneys 32 and tongue chimneys 34 in a shoe. The view of
While
The chimneys described in the embodiments above are generally applicable to all manner of footwear. However, foot coverings designed to snugly fit about the wearer's foot, such as socks, create special needs that should be addressed in order to effectively vent heat and moisture. One obvious issue with conformal or form-fitting foot coverings is the need for comfort. While the chimneys are structures described above may be used, if the chimney structure is too rigid or firm, it will likely be uncomfortable to the wearer. However, if the chimney structure is too soft or pliable, the pathways of the chimneys will collapse and prevent heat and moisture evacuation. Therefore, the chimney structure should be capable of retaining its venting abilities even after repeated cleanings.
Heat and/or moisture are vented along the chimneys 706 as seen by the arrows in
FIGS. 12(b) and 12(c) illustrate the elasticized chimney structure 700 in compressed and stretched positions, respectively. As seen in
In another alternative shown in
FIGS. 12(g) and 12(h) illustrate perspective and top views of the elasticized chimney structure 700 with the covers 708 and 710 omitted.
The collar 724 includes an opening 734 at a first end thereof for receiving the foot. The collar 724 is preferably formed of a breathable material which can be flexible and/or elastic. The height of the collar 724 and/or the height of the body 722 may vary depending on the type of sock or legging, e.g., crew sock, running sock, skiing sock, tube sock. By way of example only, the height of the collar 724 may be on the order of 40 mm and the height of the body may be on the order of 90 mm. The collar 724 typically is positioned at or above the ankle. The chimneys 706 of the chimney structure 700 desirably extend at least partly into the collar 724, and may extend all the way to the top of the collar 724.
Optionally, the sock 720 may include a scree skirt 736. The scree skirt 736 may be disposed at or near the wearer's ankle, and may delineate the transition between the sock body 722 and the collar 724. When worn in conjunction with a shoe, such as a climbing shoe, the scree skirt 736 helps prevent rocks, dust, and other debris from entering the shoe and causing discomfort to the wearer. The scree skirt 736 may include a pocket 738 to hold the laces of the shoe. The pocket is preferably a rubberized stretch pocket that can be formed using mesh or other suitable materials.
The chimney structure 700, inner lining 740 and/or outer lining 742 may be integral with or removable from the sock or legging 720. For example, in one embodiment, the chimney structure 700, the inner lining 740 and the outer lining 742 are all integrally formed as part of the sock 720. In another embodiment, the outer covering 732 comprises the outer lining 742, and the chimney structure 700 and the inner lining 740 are removably insertable into the outer covering 732. In this case, the chimney structure 700 and the inner lining 740 may be integrally formed or may comprise separate components.
Many different chimneys and chimney structures have been illustrated and described above. These structures should be designed so that the pathways therein provide efficient evacuation from the shoe microclimate. The effectiveness of the pathways is tied to their cross-sectional area. While it might be assumed that the larger the cross-sectional area the better, in reality one cannot design footwear having arbitrarily large chimneys, as this may impinge on the structural characteristics of the footwear.
In order to determine suitable chimney sizes, various laboratory tests were performed. Testing was conducted using SATRA standard tests. Specifically, the AMM testing discussed above was performed using SATRA Test Method 376 dV. The tests were conducted on footwear implementing chimneys in accordance with aspects of the invention. Testing compared the effects of the chimneys in various footwear structures against a control structure without chimneys. Testing simulated the generation of heat and sweat by the foot in a shoe, quantifying the distribution of sweat output by absorption (e.g., absorption by the skin, sock, footbed, shoe upper, etc.), evaporation, and energy usage.
Experiments were carried out to examine effect of chimneys on moisture management. These experiments were also used to characterize chimney geometry in an effort to optimize performance. Lastly, testing was designed to look at the performance of different fabrication techniques and the effect of chimney hardness on moisture management performance.
Moisture management testing was conducted under the same laboratory conditions discussed above with regard to Tables 5 and 6. The external environment was maintained at 20° C. and 65% relative humidity. A simulated foot was used to conduct the test. The simulated foot was covered in a simulated skin membrane. A sock having the composition 42% cotton, 14.5% spandex, 21.5% nylon, and 22% polyester was placed on simulated foot and inserted in shoe under test. The foot was maintained at a temperature of 34° C. with a nominal sweat rate of 5 mL/hr. A constant airspeed of 2 m/s was maintained across the shoe during the test.
The chimney moisture management test compared five different hiking shoes. One of the shoes was a commercial off the shelf hiking shoe. Another shoe was fabricated by taking the commercial hiking shoe and removing the lining package in the upper. An EVA foam insert without chimneys replaced the lining package. The other three shoes employed EVA foam inserts with the open-ended rectangular chimney structures discussed above with regard to
Data showed an increase in ventilation performance as chimney pathway cross section increased from 0 mm2 to 48 mm2. For example, as compared to the commercial shoe, the shoe having pathways 8 mm wide and 4 mm deep (32 mm2) was found to create approximately an 84.4% increase in the evaporative moisture loss. Similarly, compared to the commercial shoe, the shoe having pathways 12 mm wide and 4 mm deep (48 mm2) was found to create more a 108% increase in the evaporative moisture loss. Notably, in the commercial shoe the moisture was not absorbed by the synthetic skin or the sock to the degree found in the insert without chimneys or the insert having the 4 mm×4 mm structure. However, in the commercial shoe test a substantial amount of moisture was absorbed by the shoe and by the footbed itself. Furthermore, the control shoe having the EVA insert without chimneys performed slightly worse than the commercial shoe, with an evaporation loss on the order of 8% worse than the commercial shoe.
Overall, it is clearly seen that the larger area chimneys provided significant and substantial improvement in the microclimate of shoes when compared against the commercially available shoe. However, even the smallest chimney structure produced at least a 21% increase in evaporation loss as compared to the commercial shoe. Thus, the testing shows that small, medium and large size chimneys can greatly improve moisture evaporation
While the use of chimneys in footwear and foot coverings is important to regulate the microclimate, how the chimneys are made and what they are made from can impact their performance. It has been determined that common manufacturing techniques may be used for chimney construction.
Multiple potential fabrication techniques were analyzed to determine if there was a difference in performance. These fabrication techniques included molded fabric with poured PU, compression molded EVA with a sprayed flocking, and compression molded EVA with a fabric laminate. Boots fabricated using the aforementioned techniques were tested in accordance with the SATRA AMM test. Table 8 illustrates these test results.
All of the fabrication techniques demonstrated substantial improvement over a conventional production shoe without chimneys, as shown above with regard to Table 7. In particular, the molded fabric with poured PU demonstrated the greatest performance increase in evaporated moisture loss, approximately 69% increase over production footwear. The compression molded EVA with sprayed flocking had approximately a 33% increase in moisture loss, and the compression molded EVA with fabric laminate had nearly a 55% increase.
In addition to chimney materials, the effect of chimney hardness on moisture management performance was also examined in view of durability and comfort. Different footwear were created and tested with finished chimney hardness chosen as 10, 20, and 30 on the Asker C scale. Table 9 illustrates the chimney hardness moisture accumulation and evaporation test results.
Table 9:
In each test, the evaporative loss was substantially greater than in the commercial shoe of Table 7. Although not statistically significant in terms of evaporative moisture loss, chimneys with an Asker C hardness on the order of 20 offered an improvement over similar chimneys with different hardness. In one preferred example includes chimneys having a hardness of at least 15-20 Asker C. In another example, the chimneys desirably have a harness of between 25 and 35 Asker C.
As discussed earlier, chimneys in accordance with the present invention have proven to provide superior ventilation, allowing warm air to rise out of the boot and carry moisture away. In general, a variety of chimney widths can be used. Construction type, materials, footwear design and end use play a role in the optimal placement and dimensions of channels. Testing has proven that evaporation and the removal of moisture increases as chimney width increases. This results in dryer socks and skin and, in general terms, increased comfort. Chimneys may be incorporated into all types of footwear, including but not limited to protective footwear, in varying geometries and placements.
Channels incorporated into the tongue area of a boot or other shoe may be wider than channels incorporated into the heel area. One reason is that there are more sweat glands located on the top of the foot than in the heel. Another reason is that air circulation from the medial and lateral surface areas of the foot benefit greatly from placement of wider channels on the tongue to allow for enhanced overall evaporation of moisture.
A variety of materials can be used for construction of the chimneys such as PU and EVA foams as well as polymer gels. Additionally, a variety of liner materials can be used to enhance the moisture management, the heat transfer process and/or provide additional insulation, comfort or protection. Synthetic materials such as spandex, nylon, polyester, polypropylene or natural fibers such as wool can be used as lining material. In most cases, the traditional materials used for footwear manufacturing do not need to be altered in order to incorporate the current invention. The only requirement is that one of the layers includes a material that can be molded into a shape that forms a chimney. Moldable materials, such as moldable foams and plastics commonly used in contemporary footwear, may be utilized.
As discussed above, any type of footbed may be used in accordance with the chimneys of the present invention. However, it can be desirable in many situations to utilize specialty footbeds to enhance the convection and vent heat and moisture away from the foot. FIGS. 15(a)-(f) illustrate an exemplary footbed 800 that may be used in conjunction with the chimneys of the present invention. As seen in the top view of
As seen in the side view of
A heel cup 810 is preferably disposed over the bottom plate 808 at least along the heel region 806. The heel cup 810 may extend forward into the sole region 804. The heel cup 810 may comprise EVA foam or other material. The bottom plate 808 and the heel cup 810 may be cemented and compression molded together during fabrication.
Overlying the bottom plate 808 and the optional heel cup 810 is an airflow chassis 812. The airflow chassis 812 preferably comprises a mesh-like material such as nylon, plastic, polyester, etc. The porous structure of the airflow chassis 812 enables heat and moisture to vent away from the foot. The airflow chassis 812 may include a top liner 814, a bottom liner 816, or both. Preferably, the hardness of the material of the airflow chassis 812 is between 40-70 on the Asker C scale. More preferably, the hardness is between 50-55 on the Asker C scale. The airflow chassis 812 may be cemented or otherwise affixed to the bottom plate 808 and the heel cup 810.
As best seen in the bottom view of
The longitudinal opening 818, the transverse openings 820 and the lip 822 all help to promote movement of air away from the bottom of the foot. For example,
Returning to
It should be understood that while the footbed 800 is preferably used in combination with chimneys and chimney structures as disclosed herein, it is possible to utilize the footbed 800 without chimneys. In this case, the footbed 800 will provide the benefit of air circulation under and around the foot. The footbed 800 could be used with footwear that may not lend itself to the use of chimneys. By way of example only, open-toed sandals or similar structures may not derive substantial benefit from large chimney structures; however, the footbed 800 would still be quite suitable in this situation. It should also be understood that the footbed may be removable or permanently secured to an article of footwear.
The present invention was developed, in part, to enhance the natural processes of sweating and evaporation that the body uses to regulate temperature, thus breaking the traditional, unsuccessful compromise that exists today in conventional footwear. By incorporating chimneys in accordance with various embodiments of the invention in the sidewalls and tongue portions of the footwear, or in the foot covering worn with or without such footwear, these natural processes are effectively promoted to ensure a more consistent range of temperature, moisture and comfort. Testing of various embodiments of the invention has proven that chimneys are an effective means of temperature regulation without interfering with the integrity of the particular protective characteristics of the shoe, such as waterproofing, insulation, durability, support, etc. An air permeable footbed, for example a mesh footbed, can also be used in conjunction with the chimneys and structures discussed herein to further promote airflow around the foot.
It can be seen that chimneys of various geometries can effectively vent heat and moisture from footwear. The different geometries can be mixed and matched within a given shoe to optimize ventilation and to enhance comfort. By way of example only, the chimneys may be squared, rounded, rectangular or mixed. The chimneys may be open on one or both sides. They may be substantially vertical, or angled, arched, s-shaped, curved, etc. A covering, if used, can be a breathable, wicking material, such as mesh. Depending on construction type, footwear design, materials, and comfort requirements, an open channel may be suitable, or a covered channel may be preferred. Alternatively, there may be a combination of open and covered chimneys in the same article of footwear.
It is possible to replace a chimney or a chimney structure with another chimney or chimney structure. For instance, the chimney or chimney structure may be a removable insert, providing interchangeability depending on the type of activity, the external environment, etc. For example, the wearer may replace a chimney or chimney structure for cleaning. Alternatively, the in shoe chimney or chimney structure may be exchanged for another chimney or chimney structure having different characteristics or parameters. In this case, the wearer could select the chimney or chimney structure to have a particular cross-sectional area, shape, material, etc. based upon environmental conditions, a sport or activity, or a personal preference.
Footwear can be constructed in such a way as to provide an upper and bottom that can receive a variety of inserts depending on activity and climate requirements. By way of example only, a hiking boot with a leather or synthetic upper that has been combined with a breathable, waterproof membrane such as a hydrophobic PTFE may be purchased with two channel inserts. One insert can be used for warm weather and is made of low density foam with perforations for ventilation (e.g., holes or slits). The foam may be laminated with a lightweight breathable material (e.g., polyester, spandex, nylon, polypropylene or blend) that is appropriate given the climate requirements and promotes heat and moisture transfer/evaporation that is needed to assist in regulating the microclimate within the shoe. The second insert may be preferable in cold, wet weather conditions and can be made of foam having a higher density than the first insert. This foam insert can be laminated to an insulating material such as wool, fleece, and/or a non-woven batting material to provide insulation from the external climate while the chimneys regulate heat and moisture transfer/evaporation to provide a more constant and comfortable internal microclimate.
The chimneys and chimney structures disclosed herein may be incorporated into all manner of footwear, such as shoes, and foot coverings such as socks and leggings, and can also be incorporated into apparel such as gloves, pants, shirts, jackets, hats, helmets, etc. PU chimneys may be incorporated into the sock material, for example placed between two layers of a wicking breathable material such as polyester, which allows for the evaporative moisture loss enhanced by convection. In this case, the sock could be worn with conventional shoes, or could also be worn with shoes incorporating chimney structures themselves.
A wide variety of materials can be used to achieve the chimneys of the present invention. Materials such as reticulated foam may be used to form chimneys, and the porous structure can enhance ventilation. The materials can be molded and formed appropriately to the design of the footwear. For example, foam materials can be exposed in surface areas on the upper and/or the top opening of the shoe remains open or exposed to allow for ventilation of heat.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. By way of example only, while different embodiments described above illustrate specific features, it is within the scope of the present invention to combine or interchange different features among the various embodiments to create other variants. Any of the features in any of the embodiments can be combined or interchanged with any other features in any of the other embodiments. The invention can be used in combination with new or uncommon materials in addition to the materials specified above, as well as with new or uncommon manufacturing techniques.
