Patent Application
20130031805
This disclosure relates to articles of footwear.
In general, shoes, a type of footwear, include an upper portion and a sole. When the upper portion is secured to the sole, the upper portion and the sole together define a void that is configured to securely and comfortably hold a wearer's foot. Often, the upper portion and/or sole are/is formed from multiple layers that can be stitched or adhesively bonded together. For example, the upper portion can be made of a combination of leather and fabric, or foam and fabric, and the sole can be formed from at least one layer of natural rubber. Often materials are chosen for functional reasons, e.g., water-resistance, durability, abrasion-resistance, and breathability, while shape, texture, and color are used to promote the aesthetic qualities of the shoe.
In one aspect of the invention, an article of footwear includes a footwear upper and a sole assembly secured to the footwear upper. The sole assembly includes an outsole, a midsole disposed on the outsole and having a heel portion that defines a void, and first and second inserts disposed in the void. The first insert is attached to the outsole, and the second insert is disposed on top of the first insert in a manner such that the first and second inserts are movable relative to one another.
In another aspect of the invention, a sole assembly for an article of footwear includes an outsole, a midsole disposed on the outsole and having a heel portion that defines a void, and first and second inserts disposed in the void. The first insert is attached to the outsole, and the second insert is disposed on top of the first insert in a manner such that the first and second inserts are movable relative to one another.
Implementations can include one or more of the following features.
In some implementations, a portion of the second insert extends above (e.g., 1.0 mm to 3.0 mm above) top surfaces of the midsole that are adjacent to the void.
In certain implementations, the second insert is more compliant than the first insert.
In some implementations, the first insert is formed of a material having a durometer of 50 Asker C to 55 Asker C, and the second insert is formed of a material having a durometer of 40 Asker C to 45 Asker C.
In certain implementations, the first and second inserts are more compliant than the midsole.
In some implementations, the midsole includes at least one of a polyurethane and ethylene vinyl acetate.
In certain implementations, the first insert is formed of ethylene vinyl acetate having a durometer of 50 Asker C to 55 Asker C, the second insert is formed of ethylene vinyl acetate having a durometer of 40 Asker C to 45 Asker C, and the midsole is formed of ethylene vinyl acetate having a durometer of 50 Asker C to 55 Asker C.
In some implementations, the first insert is thermally bonded to the outsole.
In certain implementations, the void is sized to accommodate a heel of a wearer of the article of footwear.
In some implementations, the outsole defines a siped bottom surface.
In certain implementations, the outsole includes at least one of isobutylene rubber, butadiene rubber, styrene butadiene rubber and natural rubber.
In some implementations, the first and second inserts are formed of one or more high rebound materials (e.g., one or more materials having a resilience of 45-60 percent, as determined by the ASTM D2632 resilience test).
In certain implementations, the article of footwear further includes a footbed having a base that defines a cavity in a heel region of the footbed and an insert disposed in the cavity. The insert is formed of a material having a durometer of 30 Asker C to 35 Asker C (e.g., 33 Asker C).
In some implementations, the cavity is configured to receive a heel bone of a wearer of the article of footwear.
In certain implementations, the base is formed of a material having a durometer of 35 Asker C to 40 Asker C.
In some implementations, the base is formed of ethylene vinyl acetate.
In certain implementations, the insert is formed of thermoplastic elastomer.
In some implementations, the insert has a thickness of 2 mm to 10 mm (e.g., 4 mm).
Other aspects, features, and advantages will be apparent from the description and drawings, and from the claims.
Shock and vibrations experienced while boating, in particular power boating, can cause fatigue and even muscle soreness. A person can experience forces, translated from a power boat deck, several times that of running. A reduction in the shock and vibrations experienced while boating typically enhances the boating experience. The present disclosure describes a sole assembly, and, in some examples, a shoe that reduces the shock and vibrations experienced while boating, thereby likely reducing fatigue and enhancing enjoyment of boating. The sole assemblies and shoes described herein have been found to reduce shock and vibrations more effectively than various running shoes, which many people have chosen to wear in the past while boating.
Referring to
As shown in
As shown in
When shock and vibrations are applied to the heel portion 202 of the sole assembly 200, those forces and vibrations are in large part absorbed by the shock absorption inserts 122, 124. As a result, ground contact forces directly below the heel are substantially mitigated prior to be transmitted to the heel of the wearer. In this way, the shock absorption inserts 122, 124 reduce a wearer's exposure to shock and vibrations from a moving surface, such as the deck of a boat. Without wishing to be bound by theory, it is believed that the material selection of the shock absorption inserts 122, 124 and the ability of the shock absorption inserts 122, 124 to move slightly relative to one another enhances the ability of the heel portion 202 of the sole assembly 200 to mitigate forces and vibrations transmitted to the heel of the wearer during use.
Still referring to
The void 120 formed in the midsole 220, as noted above, is sized and shaped to accommodate a wearer's heel. In an average size adult shoe (e.g., a size 9D shoe), the void 120 has a width of about 40 mm to about 50 mm (e.g., about 45 mm) and a length of about 60 mm to about 70 mm (e.g., about 65 mm). The top and bottom shock absorption inserts 122, 124 are substantially the same size as the void 120 such that the shock absorption inserts 122, 124 can be securely positioned within the void 120 with limited front-to-back and side-to-side movement relative to the midsole 220.
The depth of the void and the thicknesses of the shock absorption inserts 122, 124 are dependent on the thickness of the sole assembly to be used for a particular style of shoe. In many implementations, the void 120 has a depth of about 8 mm to about 20 mm (e.g., about 15 mm to about 20 mm), the top shock absorption insert 122 has a thickness of about 2 mm to about 8 mm (e.g., about 4 mm to about 6 mm), and the bottom shock absorption insert 124 has a thickness of about 8 mm to about 16 mm (e.g., about 11 mm to about 13 mm).
As shown in
The outsole 210 is formed of a material that provides further dampening and shock absorption. The outsole 210 is typically formed of thermoset elastomeric material, such as natural rubber. In some implementations, the outsole 210 is formed of a rubber compound including isobutylene rubber, butadiene rubber, styrene butadiene rubber and/or natural rubber, which exhibits a balance of traction and shock absorbing characteristics. The outsole 210 can have a durometer of 40 Shore A to 70 Shore A (e.g., 50 Shore A). The outsole 210, as shown in
In some implementations, the shoe 100 includes a removable footbed (not shown). The footbed includes a base that is formed of EVA having a durometer of 35 Asker C to 40 Asker C and defines a cavity in its heel region. The cavity of the footbed, like the cavity 120 of the midsole 220 on which the footbed sits, is typically sized and shaped to accommodate or receive a wearer's heel bone. The insert is typically formed of thermoplastic elastomer (TPE) having a durometer of 30 Asker C to 35 Asker C (e.g., 33 Asker C) and a thickness of 2 mm to 10 mm (e.g., about 4 mm). It has been found that using a footbed of this type in combination with the sole assembly 200 enhances the shock absorbing capabilities of the shoe 100.
While standing on a moving surface (e.g. boat deck), a person's ability to press his/her toes downwardly against the surface affects that person's stability on the moving surface. In some implementations, the shoe 100 includes a toe box portion configured to allow a user to easily press one or more of his/her toes downwardly against a supporting surface. The shoe 100 defines a toe spring of 1 mm to 20 mm (e.g., 15 mm) to bring the toes of a user within close proximity of the supporting surface and prevent forward rocking exhibited by shoes with greater toe springs (e.g. as with typical running shoes). As a result, this toe spring is not a mere cosmetic design choice, but instead, is chosen to provide a specific level of shoe stability suitable for standing on moving surfaces, such as the deck of a boat. Generally, shoe designers select a toe spring that is considered aesthetically pleasing. However, this larger toe spring lends the shoe to forward rocking and increases the distance user must flex his/her toes downwardly to increase stability. An upper portion of the toe box portion is constructed of one or more flexible materials to allow easy flexion of the toe box portion upwardly and downwardly. Again, a user's ability to easily flex his/her toes downwardly increases stability and prevents rocking.
The shock and vibration absorption properties of individual materials and/or constructed shoes may be measured using the following testing procedure. Referring to
In the example shown, right and left sole assemblies 200 are placed on the base fixture plate 610. A heel block 630 (e.g., an aluminum block having a length of about 38 mm, a width of about 38 mm, and a thickness of about 26 mm high) is used to simulate the heel bone and is placed substantially centered on the heel portion 202 of each sole assembly 200 with a rearward edge located a distance D of about 15% an overall length L of the sole assembly 200. A weight 640 (e.g., steel bar having length of 465 mm, width of 100 mm, and height of 50.5 mm and weighing 42 lbs (19 kg)) is placed over the heel block 630 in the heel portion 202 of each sole assembly 200. The cross bar 620 secures the weight 640 in place. Nuts 627, 629 are tightened on the respective threaded cross bar rods 626, 628 to 1 in-lb for shock testing and 10 in-lb for vibration testing. A rubber pad 642 having a thickness of about ¼ inch (6.35 mm), a durometer of between about 50 Shore A and about 55 Shore A, a length of 100 mm, and a width of about 39 mm is inserted between cross bar 620 and the weight 640 to deaden any ringing generated there between. A monitor accelerometer 650 is disposed on the weight 640 (e.g., about 1 inch (25.4 mm)) from the cross bar 620, which is centered width-wise on the weight 640. The monitor accelerometer 650 measure shock and vibrations that a supposed user of the sole assembly 200 would experience. A control accelerometer 660 is disposed on the base fixture plate 610 for measuring the actual input shocks and vibrations (in g's) delivered by the shaker table 600.
A minimum of 5 test repetitions at least 2 hours apart and on at least 2 different days should be executed to acquire data. In addition, “control samples” should be the first and last samples tested each day. Control samples are a predetermined group of items, generally selected towards the beginning of the project (3-5 samples is reasonable). Often, these “controls” are the project benchmarks, most relevant items, or the best performing sample(s) (can be shoes, materials, or assembled parts). Check that “control” results are similar through the course of day and from one day to the next.
Shock testing includes performing sine shock pulses on the shaker table 600 as follows (all with 10 ms durations): 1 g pulse, then re-torque the nuts 627, 629; 3 g pulse, then re-torque the nuts 627, 629; and 5 g pulse, then re-torque the nuts 627, 629. Vibration testing includes performing a half-sine sweep 5-200 Hz at 0.5 g's at 1 octave per minute on the shaker table 600. Signals of the monitor accelerometer 650 and the control accelerometer 660 are recorded during execution of the testing.
Table 1 below provides summary of shock testing results across a number of shoes, including the shoe 100 (referred to as “ASV Production” in the table) and a number of shoes without the shock absorbing inserts described herein. While shock testing with a sine shock pulse at 1 g, the shoe 100 (ASV) provided a 27% reduction in the shock wave transmitted to a user's heel relative to wearing no shoe, while shoes without the shock absorbing inserts described herein provided between an 21% reduction and a 36% amplification of the shock wave. While shock testing with a sine shock pulse at 3 g's, the shoe 100 (ASV) provided a 41% reduction in the shock wave transmitted to a user's heel relative to wearing no shoe, while shoes without the shock absorbing inserts described herein provided between a 38% reduction and a 21% amplification of the shock wave. While shock testing with a sine shock pulse at 5 g's, the shoe 100 (ASV) provided a 45% reduction in the shock wave transmitted to a user's heel relative to wearing no shoe, while shoes without the shock absorbing inserts described herein provided between a 41% reduction and a 26% amplification of the shock wave.
Across all of the shoes tested the ASV shoe provided the greatest reduction in shock transmission to a user.
While certain implementations have been described, other implementations are possible.
While the shock absorption inserts 122, 124 have been described as being formed of EVA, other materials can alternatively or additionally be used to effectively dampen shock and vibrations acting on the heel region 202 of the shoe 100. Examples of other materials from which the shock absorption inserts 122, 124 can be formed include polyurethane foam and TPE foam.
It has been found that certain combinations of shock absorption insert materials are particularly effective at absorbing shock and vibrations acting on the heel portion 202 of the sole assembly 200 of the shoe 100. For example, using high rebound materials for the top and bottom inserts 122, 124 can provide desirable results. High rebound materials are materials having a resilience of 45-60 percent, as determined by the ASTM D2632 resilience test. In some implementations, the top shock absorption insert 122 is formed of TPE having a durometer of 30 Asker C to 35 Asker C (e.g., 33 Asker C) and the bottom shock absorption insert 124 is formed of EVA having a durometer of 50 Asker C to 55 Asker C.
It is believed that using high rebound materials to form the top insert 122 and high shock absorbing materials (e.g., materials having a resilience of 20 percent or less, as determined by the ASTM D2632 resilience test) to form the bottom insert 124 can also provide suitable shock and vibration absorption. In certain implementations, for example, the top shock absorption insert 122 is formed of EVA having a durometer of 40 Asker C to 45 Asker C and the bottom shock absorption insert 124 is formed of polyurethane foam having a durometer of 50 Asker C to 55 Asker C.
While the midsole 220 has been described as being formed of EVA in certain implementations discussed above, the midsole 220 can alternatively or additionally be constructed of one or more other shock absorbing materials, such as shock absorbing polyurethane. In some implementations, the midsole 220 has a durometer of 40 Asker C to 70 Asker C (e.g., 50 Asker C).
While the midsole 220 has been illustrated as directly contacting and resting on the outsole 210 in the forefoot portion of the sole assembly 200, in some implementations, the forefoot portion of the sole assembly 200 includes a forefoot cushion layer disposed between the outsole 210 and the midsole 220. The cushion layer can, for example, be disposed in a recess defined in a forefoot region of the midsole 220. The forefoot cushion layer provides additional shock absorption and cushioning for a user's foot. The forefoot cushion layer can be made of polyurethane (e.g. polyurethane foam) and can have a durometer of 40 Asker C to 70 Asker C (e.g., 50 Asker C).
While the sole assembly 200 has been described as including two inserts 122, 124 within the cavity 120 defined by the midsole 220, more than two inserts (e.g., three, four, five, or six inserts) can alternatively be used.
While the footbed has been described as being removable, in certain cases, the footbed may be permanently affixed within the shoe.
While the insert for the footbed has been described as being formed of TPE, in certain implementations, the footbed insert can be formed of other high rebound materials, such as EVA having a durometer of 40 Asker C to 45 Asker C.
Although the sole assembly 200 has been shown as being attached to a shoe, it may be used for other types of articles of footwear, including, but not limited to boots, sandals, flip-flops, etc.
While the footwear have been described as reduce shock and vibrations that are transmitted to the heel of the wearer from the deck of a boat, it should be understood that the footwear described herein can be used to reduce such shock and vibrations from a variety of other moving surfaces, such as construction vehicles, large machinery, etc.
Other implementations are within the scope of the following claims.
This application claims the benefit of U.S. Provisional Application Ser. No. 61/513,817, filed on Aug. 1, 2011, which is incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 61513817 | Aug 2011 | US |
