US20140311187A1

US20140311187A1 - Performance dress sock

Info

Publication number: US20140311187A1
Application number: US14/215,932
Authority: US
Inventors: Gihan S. Amarasiriwardena; Aman Advani; Claudia Richardson; Caitlin Hickey
Original assignee: Ministry of Supply
Current assignee: Ministry of Supply
Priority date: 2013-03-15
Filing date: 2014-03-17
Publication date: 2014-10-23

Abstract

A sock having a low pressure area made of a first knit density and at least one high pressure area made of a variable knit density portion. The variable knit density has portions that are made of a second knit density greater than the first knit density. The at least one variable knit density portion is arranged transverse to an orientation of major strain. A sock may also have hydrophobic fibers located substantially across a surface of the sock adapted to be adjacent to skin when worn and hydrophilic fibers located substantially across the hydrophobic fibers and extending therefrom to form loop structures adapted for wicking moisture away from the hydrophobic fibers.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent Application No. 61/791,208, filed on Mar. 15, 2013, which is incorporated herein by reference as if set forth in its entirety.

FIELD OF THE INVENTION

This invention relates generally to performance apparel and, particularly, to performance dress socks.

BACKGROUND

Socks pose a particularly difficult problem with respect to performance as they experience significant strain during walking due to movement of the foot throughout a gait cycle. Further, stresses in socks are amplified as a significant portion of a wearer's weight is placed on each foot while walking Often, compromises are made to provide either a sock that is durable but inappropriate for office wear (e.g., athletic socks) or a sock that is designed for appearance and wear with office attire (e.g., dress socks) that tends not to be as durable. Also, many socks are manufactured with a substantially constant knit density, which tends to provide either cushioning (in the case of a higher knit density) or dynamic stretch properties (in the case of a lower knit density). Therefore, there is a need for durable, comfortable socks that are considered appropriate for wear in professional environments, and that also provide a combination of cushioning and dynamic stretch abilities.

SUMMARY OF THE INVENTION

Embodiments of a performance dress sock incorporate select materials and construction to improve wearer comfort and durability of the wares while maintaining a professional appearance (e.g., in an office setting). The performance dress sock can have a half-calf or mid-calf arrangement with the upper part of the sock largely driven by aesthetic considerations, as opposed to typical socks which maintain a relatively
In one aspect, the invention relates to a sock having a low pressure area made of a first knit density and at least one high pressure area made of a variable knit density portion. The variable knit density has portions that are made of a second knit density greater than the first knit density. The at least one variable knit density portion is arranged transverse to an orientation of major strain.
In one embodiment of the above aspect, the variable density portion is located in a portion corresponding to a metatarsal region of a foot when the sock is worn. The variable density portion may be arranged transverse to a line connecting a first metatarsophalangeal joint region to a fifth metatarsophalangeal joint region. The variable density portion may be a pattern. The pattern may be a plurality of polygons, and the pattern may be a grid. In some embodiments, the sock has a frictional surface adapted to be aligned along an orientation of minor strain. The frictional surface may be located in a rear portion of the sock, and the frictional surface may be one or more strips. In certain embodiments, the frictional surface is made of at least one of urethane and silicone.
In some embodiments, the sock has a third knit density portion (with a knit density greater than the first knit density) near an area corresponding to an arch of a foot when the sock is worn. The third knit density portion may extend around the sock to surround the arch area when the sock is worn. In certain embodiments, the sock is a dress sock. The sock may be made of synthetic polyester comprising activated charcoal, such as coffee grounds.
In another aspect, the invention relates to a sock having hydrophobic fibers located substantially across a surface of the sock adapted to be adjacent to skin when the sock is worn. The sock also has hydrophilic fibers located substantially across the hydrophobic fibers and extending therefrom to form loop structures adapted for wicking moisture away from the hydrophobic fibers.
In one embodiment, the sock has a greater amount of hydrophilic fibers than hydrophobic fibers. The sock may have about a 75/25 ratio of hydrophilic fibers to hydrophobic fibers.
In another aspect, the invention relates to a method of manufacturing a performance dress sock. The method includes the steps of robotically knitting a low pressure area of the sock at a first knit density and robotically knitting a high pressure area of the sock at a variable knit density. The variable knit density has portions having a second knit density greater the first knit density. The at least one variable knit density portion is arranged transverse to an orientation of major strain.

BRIEF DESCRIPTION OF THE FIGURES

Other features and advantages of the present invention, as well as the invention itself, can be more fully understood from the following description of the various embodiments, when read together with the accompanying drawings, in which:

FIG. 1A is a depiction of a strain profile obtained through experimentation with orientations of strain and an outline of a foot superimposed thereon;

FIG. 1B is a schematic bottom view of a sock designed taking into consideration the strain profile of FIG. 1A and the pressure profile of FIG. 2, in accordance with one embodiment of the invention;

FIG. 2 is a depiction of a pressure profile obtained through experimentation with an outline of a foot superimposed thereon;

FIG. 3 is a schematic, side, cross-sectional view of the sock of FIG. 1 with arrows indicating thermal escape paths, in accordance with one embodiment of the invention;

FIG. 4 is a schematic depiction of one arrangement of hydrophobic and hydrophilic fibers in relation to a skin surface, in accordance with one embodiment of the invention;

FIG. 5A is a schematic depiction of polyester fiber infused with coffee charcoal and a structure of the coffee charcoal, in accordance with one embodiment of the invention;

FIG. 5B is a magnified view of the polyester fiber infused with coffee charcoal of FIG. 5A;

FIG. 5C is a magnified view of the structure of the coffee charcoal of FIG. 5A;

FIG. 6A is an isometric view of loafer socks, in accordance with one embodiment of the invention;

FIG. 6B is a schematic, isometric view of the loafers socks of FIG. 6A with a frictional surface;

FIG. 7A is an isometric view of a performance dress sock, in accordance with one embodiment of the invention; and

FIG. 7B is a partial bottom view of the sock of FIG. 7A.

DETAILED DESCRIPTION

A performance dress sock may have several features that contribute to its performance and functioning as a second skin, beginning with an understanding of how the strain, pressure, and temperature of the foot affect various regions of the sock, as determined through body mapping. These analyses are described in detail below with respect to creating a dress sock that provides cushioning venting, and dynamic stretch properties in desired locations.
To understand skin strain dynamics on the medial, posterior, and plantar surfaces of the foot, such as where soft tissue needs support (e.g., through tension) and where skin is stretching the most, the GOM ARAMIS Optical measurement system (Braunschweig, Germany) with stereo high-speed video cameras was used to create a digital image correlation of a stochastic pattern. Six subjects with varying foot types were monitored for deformation of the foot during the walking gait cycle, with the subjects both bare foot and wearing a shoe sawn in half to understand dynamics within the shoe. Plantar strain was monitored via an optical arrangement through a transparent force plate. An exemplary result 100 (including superimposed lines 102 depicting the direction of major strain and a foot outline 104) is depicted in FIG. 1A. Based on this testing, it was determined that during midstance the arch of the foot collapses, causing major strain in a transverse direction across the arch, as depicted with the transverse arch line 106. In the metatarsal region, the orientation of major strain is angled from the first metatarsophalangeal joint (MPJ) to the fifth MPJ, as depicted with the metatarsal strain line 108. In the Achilles heel region, major strain is oriented in a substantially vertical direction.
The performance dress sock is configured to address certain issues identified in the strain analysis, and to repeatably withstand wear and support a wearer throughout various movements. For example, as depicted in an embodiment of a performance sock 110 in FIG. 1B, a compression band 112 a (e.g., an area of higher knit density) may be used in an area of the sock 110 corresponding with the arch of the foot to provide additional support. The compression band 112 a (e.g., the area of higher knit density) can apply greater tension along the direction of major strain than lower knit density areas, and can extend all the way around the foot in the arch region. The compression band 112 a may also have a higher elastane content (e.g., between about 20 and 40% by mass of the knit in the compression band 112 a) than other portions to support the arch. To reduce friction on the plantar surface (i.e., the sole of the foot), and to reduce potential for blistering, the sock 110 may allow for stretching along the direction/orientation of major strain in high pressure areas, as described in greater detail below. One way to achieve this selective stretchability is through a varied pattern (e.g., of stripes or polygons) in relatively higher 114 a and lower knit density 114 b (a variable density portion 116), which provides preference of stretch in a certain direction (e.g., along a direction of major strain as determined by the strain analysis) while still providing cushioning. The variable knit density portion 116 covered by the pattern and/or the pattern itself may be arranged substantially transverse to the direction/orientation of major strain to better maintain its characteristics even while being stretched. By allowing the sock 110 to stretch with and in the same manner as a wearer's skin, the user experiences less blistering and more comfort, while avoiding many of the problems associated with traditional socks, such as bunching and sagging.
These variable knit density portions 116 and the associated pattern may be manufactured through various techniques, including robotic knitting. The higher knit density portions 114 a (or “cushions”) may be formed on an elastic base, allowing them to move independently and with the skin. For example, the sock 110 may be made substantially of a base layer having a lower knit density (e.g., a mass ratio of approximately 80% elastane to approximately 20% hydrophobic fibers) throughout, creating a sock with good ventilation and stretching properties. To increase support, tension, and cushioning in certain areas (such as those areas determined by body mapping), additional fibers (particularly hydrophilic and/or hydrophobic fibers) may be added to increase the density and create a ratio of approximately 20% elastane, 40% hydrophobic fibers, and 40% hydrophilic materials. These are only exemplary ratios, and others are contemplated, including for lower density vented areas to be made with 100% elastane and for higher density areas to be made of approximately 80% hydrophilic material (e.g., cotton) and 20% elastane. Additionally, instead of forming a base layer and adding to it to create higher density areas, higher density and lower density areas may be formed separately through the manufacturing process (e.g., through robotic knitting). The use and arrangement of hydrophobic and hydrophilic materials is described in greater detail below.
The performance dress sock is also designed to address issues associated with the pressure profiles developed during pressure mapping, which also impacts the comfort and wear of the sock during walking To understand the pressure profiles and the correlation between stress and strain, and where feet need the most cushioning, six subjects were monitored using a Tekscan mat (South Boston, Mass.). An exemplary pressure profile 200 is depicted in FIG. 2. The pressure profile 200 illustrates that pressure is highest in the metatarsal region 202 and the calcaneal region 204, with some pressure beneath the hallux 206. The areas with high stress (or pressure) and strain are expected to experience higher friction while walking, which could very likely develop into blisters on the feet of the wearer. However, by designing a performance dress sock to allow stretching in these high pressure regions as described above (e.g., with variable knit density areas 116 and/or high knit density areas 112 b, 112 c), the risk of blisters can be greatly reduced. To preserve some of the breathability that may be lost in the high pressure regions when using high density knit cushions 114 a (which may provide cushioning and increase comfort and overall durability), areas with minimal pressure can have a lower knit density, such as on the upper side of the sock 110.
While stress and strain are important considerations in the design of the sock 110 to make it feel like a second skin, it is also important to consider the thermal effects on the wearer of such a sock. Thermal imaging may be used to identify the areas of the foot that experience the highest temperature during wear (called “hot spots”), and thus the areas that need the most ventilation. Temperature buildup may be alleviated at these hot spots by providing a path for the heat to escape outside of the sock 110, as depicted in FIG. 3. When the cushions 114 a and the lower density portions 114 b are arranged in a pattern, excess heat may more easily escape a foot through the lower density portions 114 b, even when the sock 110 is under compression. Because of the difference in thickness between the cushions 114 a and the lower density portions 114 b, channels are formed between the cushions 114 a to allow this escape. Balancing these temperature considerations with the strain and pressure considerations can lead to a much better performing and more comfortable dress sock for a wearer.
In addition to allowing for the removal of heat, the sock 110 may also be designed to remove moisture from a wearer's foot. When moisture builds up and remains against a wearer's foot, the wearer can experience an uncomfortable, clammy feeling. This feeling may remain even immediately after the moisture is removed, so it is desirable to provide a mechanism for removing moisture on an ongoing basis. Blends of hydrophobic and hydrophilic yarns (e.g., the hydrophobic synthetic polyester and the hydrophilic cotton described above) can provide higher moisture transport rates from a skin surface than a layer made of 100% hydrophobic fibers. Various ratios between the amounts of hydrophobic and the hydrophilic materials may be used, including a 60/40, a 75/25, an 80/20, and other mass ratios between and beyond these values. As arranged in FIG. 3, hydrophilic fibers 320 a can work to pull moisture away from the skin surface 322, while hydrophobic fibers 320 b spread moisture horizontally across a surface, thereby increasing surface area and accelerating evaporation of the moisture. The hydrophilic fibers 320 a and/or the hydrophobic fibers 320 b may be untreated, relying on intrinsic known material properties to provide the desired wicking and evaporation. One embodiment of a joint hydrophilic/hydrophobic arrangement is depicted in FIG. 4. Such a construction may be found in a higher knit density area 114 a, for which FIG. 4 would provide a representative schematic cross-sectional view. The hydrophobic fibers 320 b are close to the skin, distributing moisture from certain areas across a much larger surface area of the foot. The hydrophilic fibers 320 a extend away from the hydrophobic fibers 320 b, forming “reservoirs” (or loops) in which moisture may accumulate following wicking from the skin 322 and the hydrophobic fibers 320 b. The loops may be formed individually, allowing each to act as a separate reservoir, and a length of fiber forming each loop may be exposed to the environment (as opposed to trapping moisture within a layer of fabric and relying on pores for moisture to escape). The hydrophilic fibers 320 a may be woven through a base layer closest to the skin (e.g., a layer made of elastane and/or particular hydrophobic fibers) in a variety of densities, including, for example, 100 loops per square inch. In certain embodiments, additional hydrophobic fibers 320 b may be included with the hydrophilic fibers 320 a and woven together. The arrangement of hydrophilic fibers 320 a looping away from the hydrophobic fibers 320 b removes moisture from the skin 322 and provides a preferential wicking direction toward the exterior of the sock 110, allowing the wearer to feel dry even while moisture cannot be immediately removed from the environment (e.g., when wearing shoes). In this manner, the performance dress sock can provide high performance characteristics through moisture management and comfort not experienced with other dress socks.
A wearer's experience may further be improved based on the materials used, as fabric composition is a factor in both comfort and durability. The performance dress sock can include a combination of synthetic and natural products, such as a combination of synthetic polyester and long-staple cotton. Various compositions are contemplated, including an approximately 60% synthetic polyester and an approximately 40% long-staple cotton composition. The synthetic polyester can contain activated charcoal, such as that may be created through the partial combustion of used coffee grounds, as depicted in FIG. 5A. The carbon matter (coffee charcoal) 530 may be blended into the polyester 532 prior to extrusion or otherwise infused into strands of polyester 532. FIG. 5A also depicts schematically how the activated coffee charcoal 530 attracts and absorbs aromatic organic compounds and phenols 534 that commonly cause odor. FIGS. 5B depicts a greatly magnified view of the coffee charcoal 530 blended with the polyester 532, illustrating how the coffee 530 may be embedded within the polyester 532 but still exposed to the environment. FIG. 5C depicts a greatly magnified view of the coffee charcoal 530 with sponge-like pores 536 for absorbing the odor causing particles 534. Such a composition has proven to be up to three times more effective at absorbing odor as compared to regular cotton, and up over twice as effective as polyester, based on test results using ASTM Standard D 5742. While the coffee charcoal 530 absorbs odor particles 534 during wear, the odor particles 534 may be released when the socks 110 are laundered, allowing for further odor capture when worn again. The materials used in the blend may come from many sources, including recycled sources for polyester and coffee previously ground at coffee roasters and similar shops. The coffee 530 may be pharmaceutically processed prior to use in the blend to remove coffee oils to substantially remove its own scent.
FIG. 6A depicts an embodiment of the invention directed to a sock 610 in a loafer configuration. The sock 610 is largely similar to the sock 110, including a higher knit density in a metatarsal region 612 b and a sole region 612 c, a variable knit density portion 616, and a lesser knit density on a top portion 630. One difference between the sock 610 and the sock 110 is the absence of a compression band in the mid-section of the foot, though this may be included. Additionally, frictional surfaces 632 may be applied to help prevent slipping of the sock 610 on the foot, as depicted in FIG. 6B. For example, the rear portion of loafer socks 610 tend to slip below the foot when the sock 610 is stretched. By providing frictional surfaces 632 (e.g., printed strips of urethane or silicone) along the transverse lines of non-extension or minor strain along an interior heel region of the sock 610, friction can be increased in contact areas while the fabric can stretch with the skin. Typically, in traditional construction, if a frictional surface is on the rear of a sock (which often is not the case), it is applied over a relatively large, continuous surface area. This traditional frictional surface area tends to suffer from some of the same stretching issues as other areas of traditional socks, particularly down the foot in the direction of major strain at the Achilles heel. Over time, the singular large surface area tends to migrate down the foot. Using separate spaced strips 632, as depicted in FIG. 6B, allows for the sock 610 to stretch in between the strips 632 and does not substantially stretch the strips 632 themselves, such that the strips 632 remain connected to the same area of skin for the duration of wearing. This provides a consistent wear experience without the need for constant adjustments, which is particularly useful for loafers socks 610 that are cut very low so as to be non-visible when worn with loafer shoes. A low friction fabric may be used at or near the top of the loafer sock to reduce irritation.
FIGS. 7A and 7B depict a performance dress sock 710 incorporating many of the elements described above. For example, the sock 710 has areas of relatively low knit density (e.g., approximately 100 GSM) on top (dorsal) portions 730, separated by a compression band 712 a of higher knit density (e.g., approximately 200 GSM +/−15 GSM) to provide arch support. The top portions 730 are not expected to experience significant changes in pressure, so use of the light vented knit may be appropriate. Other areas that are not expected to experience changes in pressure may have the same or a similar light vented knit. In contrast, areas experiencing the greatest pressure changes, (e.g., the metatarsal and sole regions 712 b, 712 c) may have higher knit densities to increase durability. An upper part 732 of the sock 710 (i.e., the part that surrounds the calf) may have a substantially uniform medium knit density (e.g., approximately 150 GSM) to give a professional appearance, and may include a flat seam at the top to reduce irritation. An interior of the upper part 732 of the sock may also have friction surfaces (e.g., urethane strips or dots) to help prevent the socks from falling down the leg during wear. The plantar surface of the sock 710 depicted in FIG. 7B may have a padded surface 716 to provide cushioning in high pressure regions. In some embodiments, the padded surface 716 may be a grid, featuring an alternating pattern of thicker, higher knit density portions 714 a (e.g., terry knitting), and lower density knit portions 714 b. The small channels formed in such an arrangement facilitate vapor transfer even when the sock 710 is compressed against a sole of a shoe, as the variance in thickness between the higher knit density portions 714 a and the lower knit density portions 714 b is adapted to create an offset in thickness.
While the principles laid out above have been described with respect to a performance dress sock, it is easily understood that such a design process is easily applicable to other apparel, particularly apparel that touches a wearer's skin. For example, it is contemplated that shirts and underwear may be developed in the same manner as the socks described herein, e.g., by understanding the strain and pressure profiles in the areas of the body associated with the skin contacting garment and creating a design that allows for stretching with the skin of the wearer to provide comfort. This may be achieved by varying knit density across different portions of the garment, as described herein with respect to socks.
Various embodiments and features of the present invention have been described in detail with particularity. The utilities thereof can be appreciated by those skilled in the art. It should be emphasized that the above-described embodiments of the present invention merely describe certain examples implementing the invention, including the best mode, in order to set forth a clear understanding of the principles of the invention. Numerous changes, variations, and modifications can be made to the embodiments described herein and the underlying concepts, without departing from the spirit and scope of the principles of the invention. All such variations and modifications are intended to be included within the scope of the present invention, as set forth herein. The scope of the present invention is to be defined by the claims and all equivalents, rather than limited by the forgoing description of various preferred and alternative embodiments.

Claims

What is claimed is:

1. A sock comprising:

a low pressure area comprising a first knit density; and

at least one high pressure area comprising a variable knit density portion, the variable knit density comprising portions having a second knit density greater than the first knit density,

wherein the at least one variable knit density portion is arranged transverse to an orientation of major strain.

2. The sock of claim 1, wherein the at least one variable density portion is disposed in a portion corresponding to a metatarsal region of a foot when worn.

3. The sock of claim 2, wherein the variable density portion is arranged transverse to a line connecting a first metatarsophalangeal joint region to a fifth metatarsophalangeal joint region.

4. The sock of claim 1, wherein the variable density portion comprises a pattern.

5. The sock of claim 4, wherein the pattern comprises a plurality of polygons.

6. The sock of claim 1 further comprising a frictional surface adapted to be aligned along an orientation of minor strain.

7. The sock of claim 6, wherein the frictional surface is disposed in a rear portion of the sock.

8. The sock of claim 6, wherein the frictional surface comprises a plurality of strips.

9. The sock of claim 6, wherein the frictional surface comprises at least one of urethane and silicone.

10. The sock of claim 1 further comprising a third knit density portion disposed proximate an area corresponding to an arch of a foot when worn, wherein the third knit density is greater than the first knit density.

11. The sock of claim 10, wherein the third knit density portion extends around the sock and is configured to surround the arch area when the sock is worn.

12. The sock of claim 1, wherein the sock comprises a dress sock.

13. The sock of claim 1 further comprising synthetic polyester comprising activated charcoal.

14. The sock of claim 13, wherein the activated charcoal comprises coffee grounds.

15. A sock comprising:

hydrophobic fibers disposed substantially across a surface of the sock adapted to be adjacent to skin when worn; and

hydrophilic fibers disposed substantially across the hydrophobic fibers and extending therefrom to form loop structures adapted for wicking moisture away from the hydrophobic fibers.

16. The sock of claim 15, wherein the sock comprises a greater amount of hydrophilic fibers than hydrophobic fibers.

17. The sock of claim 16, wherein the sock comprises about a 75/25 ratio of hydrophilic fibers to hydrophobic fibers.

18. A method of manufacturing a performance dress sock, the method comprising the steps of:

robotically knitting a low pressure area of the sock at a first knit density; and

robotically knitting a high pressure area of the sock at a variable knit density, wherein the variable knit density comprises portions having a second knit density greater the first knit density, and wherein the at least one variable knit density portion is arranged transverse to an orientation of major strain.