PATENT DOCUMENT

Publication Number: US-11758991-B1
Application Number: US-201916553951-A
Country: US
Kind Code: B1

Title: Stretchable strands for fabric items

Abstract:
A fabric strap may be configured to attach an electronic device to a user&#39;s body. Some of the strands in the fabric strap may be stretchable strands. A stretchable strand may include an elastic core covered by one or more layers of material. The elastic core may be formed from a single elastic strand or may be formed from multiple elastic strands. The first layer of material on the elastic core may be a strand that is twisted around the elastic core. The second layer of material on the elastic core may be a strand that is braided around the first layer of material and the elastic core. The first layer may have a thickness that is greater than that of the elastic core and the second layer of material. The first and second layers of material may be formed from non-stretchable or stretchable materials.

Claims:
What is claimed is: 
     
       1. A fabric strap for an electronic device configured to be worn by a user, comprising:
 weft strands; and 
 warp strands intertwined with the weft strands, wherein the warp strands comprise a stretchable strand having a core and wherein the stretchable strand comprises:
 an elastic strand at the core, 
 a first strand twisted around the elastic strand, and 
 a second strand braided around the elastic strand and the first strand, wherein the first strand forms a first layer having a first thickness and the second strand forms a second layer having a second thickness that is less than the first thickness, wherein the stretchable strand has a volume defined by the elastic strand, the first strand, and the second strand, and wherein the first strand consumes more of the volume than the elastic strand and more of the volume than the second strand. 
 
 
     
     
       2. The fabric strap defined in  claim 1 , wherein the first strand comprises a non-stretchable material. 
     
     
       3. The fabric strap defined in  claim 2  wherein the non-stretchable material comprises polyester. 
     
     
       4. The fabric strand defined in  claim 1  wherein the elastic strand has a diameter and wherein the first thickness is greater than the diameter. 
     
     
       5. The fabric strap defined in  claim 1  wherein the elastic strand is the only elastic strand in the stretchable strand. 
     
     
       6. The fabric strap defined in  claim 1  wherein the elastic strand is one of fewer than ten elastic strands in the stretchable strand. 
     
     
       7. The fabric strap defined in  claim 1  wherein the second strand comprises non-stretchable material. 
     
     
       8. The fabric strap defined in  claim 7  wherein the non-stretchable material comprises polyester. 
     
     
       9. The fabric strap defined in  claim 1  further comprising a hook-and-loop fastener. 
     
     
       10. A stretchable layer of fabric for attaching an electronic device to a user&#39;s body, comprising:
 a first set of strands; and 
 a second set of strands intertwined with the first set of strands, wherein at least one of the first and second sets of strands includes a stretchable strand comprising:
 an elastic core, 
 a first layer of material surrounding the elastic core, and 
 a second layer of material surrounding the first layer of material and the elastic core, wherein the first layer of material has a greater thickness than the elastic core, wherein the stretchable strand has a volume defined by the elastic core, the first layer of material, and the second layer of material, and wherein the first layer of material consumes more of the volume than the elastic core and more of the volume than the second layer of material. 
 
 
     
     
       11. The stretchable layer of fabric defined in  claim 10  wherein the first layer of material has a greater thickness than the second layer of material. 
     
     
       12. The stretchable layer of fabric defined in  claim 10  wherein the first and second layers of material comprise non-elastic material. 
     
     
       13. The stretchable layer of fabric defined in  claim 12  wherein the first layer of material comprises a first strand twisted around the elastic core and wherein the second layer of material comprises a second strand braided around the first strand. 
     
     
       14. The stretchable layer of fabric defined in  claim 10  further comprising a hook-and-loop fastener. 
     
     
       15. A strap configured to attach an electronic device to a user&#39;s body, comprising:
 stretchable fabric formed from stretchable intertwined strands, wherein the stretchable intertwined strands each comprise:
 a core formed from a single elastic strand, 
 a first strand twisted around the core, and 
 a second strand twisted around the first strand and the core, wherein the first and second strands form a covering having a thickness that is greater than a diameter of the core, wherein each of the stretchable intertwined strands has a volume defined by the core, the first strand, and the second strand, and wherein the first strand consumes more of the volume than the core and more of the volume than the second strand. 
 
 
     
     
       16. The strap defined in  claim 15  wherein the first strand comprises a non-stretchable material. 
     
     
       17. The strap defined in  claim 15  further comprising a third strand braided around the second strand, the first strand, and the core. 
     
     
       18. The strap defined in  claim 17  wherein the third strand comprises polyester.

Description:
This application claims the benefit of provisional patent application No. 62/730,784, filed Sep. 13, 2018, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to fabric items and, more particularly, to fabric items for electronic devices. 
     BACKGROUND 
     Items such as wristwatches have wrist straps. Straps may be formed from materials such as metal, plastic, and fabric. It can be challenging to obtain an appropriate amount of stretch in a fabric item. If care is not taken, fabrics may not have sufficient elasticity, and stretchable fabrics may not be comfortable against a user&#39;s skin. 
     SUMMARY 
     Items such as electronic devices with straps may include fabric. For example, a strap for a wristwatch may be formed from fabric. 
     Some of the strands in a fabric strap may be stretchable strands. A stretchable strand may include an elastic core covered by one or more layers of material. The elastic core may be formed from a single elastic strand or may be formed from multiple elastic strands. The first layer of material on the elastic core may be a strand that is twisted around the elastic core. The second layer of material on the elastic core may be a strand that is braided around the first layer of material and the elastic core. The first layer may have a thickness that is greater than that of the elastic core and the second layer of material. The first and second layers of material may be formed from non-stretchable or stretchable materials. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a top view of an illustrative electronic device with a fabric strap in accordance with an embodiment. 
         FIG.  2    is a schematic diagram of an illustrative electronic device in accordance with an embodiment. 
         FIG.  3    is a cross-sectional side view of an illustrative electronic device with a wrist strap in accordance with an embodiment. 
         FIG.  4    is a cross-sectional side view of the illustrative electronic device of  FIG.  3    in a configuration in which the wrist strap has been wrapped around a user&#39;s wrist in accordance with an embodiment. 
         FIG.  5 A  is a cross-sectional side view of an illustrative fabric layer in a strap in an unstretched configuration in accordance with an embodiment. 
         FIG.  5 B  is a cross-sectional side view of the fabric layer of  FIG.  5 A  in a stretched configuration in accordance with an embodiment. 
         FIG.  6    is a cross-sectional side view of an illustrative stretchable strand having an elastic core formed from a bundle of elastic strands in accordance with an embodiment. 
         FIG.  7    is a cross-sectional side view of an illustrative stretchable strand having an elastic core covered by a layer of material in accordance with an embodiment. 
         FIG.  8    is a cross-sectional side view of an illustrative stretchable strand having an elastic core covered by first and second layers of material in accordance with an embodiment. 
         FIG.  9    is a cross-sectional side view of an illustrative stretchable strand having an elastic core formed from multiple elastic strands that are covered by first and second layers of material in accordance with an embodiment. 
         FIG.  10    is a side view of an illustrative stretchable strand having an elastic core and a covering formed from a strand of material that is twisted around the elastic core in accordance with an embodiment. 
         FIG.  11    is a side view of an illustrative stretchable strand having an elastic core and first and second coverings formed from strands of material that are twisted around the elastic core in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with fabric. The fabric may be used to form straps or other fabric items for an electronic device. The fabric may be woven fabric or knit fabric or may be formed by intertwining strands of material using braiding techniques or other intertwining techniques. The electronic devices may be wristwatches, fitness bands, or other electronic devices. Illustrative configurations in which portable electronic devices such as wristwatch devices or other wrist-mounted portable electronic devices are provided with woven fabric straps may sometimes be described herein as an example. In general, any suitable portable electronic device may be provided with a strap and the strap may be formed from any suitable fabric material. The straps or other fabric structures may be used to attach the portable electronic device to an arm, leg, head, torso, wrist, or other portion of a user&#39;s body. 
     An illustrative electronic device is shown in  FIG.  1   . As shown in  FIG.  1   , device  10  may have a display such as display  14  and other electrical components mounted in a housing such as housing  12 . Device  10  may be a portable electronic device such as a device that is mounted on a user&#39;s wrist, arm, leg, head, torso, or other body part. Device  10  may, for example, be a wrist-mounted device such as a wristwatch, a health monitoring device, a media player, a wireless key, or other electronic device and/or equipment that includes the functions of two or more of these devices or other suitable devices. Housing  12  (e.g., a watch housing in scenarios in which device  10  is a wristwatch) may be formed from metal, ceramic, plastic, glass, sapphire or other crystalline materials, and/or other suitable materials. Housing  12  may have a rectangular outline, may have an oval or circular shape, or may have other suitable shapes. Display  14  may be a liquid crystal display, an organic light-emitting diode display, or other suitable display. 
     Strap  16  may have portions attached to opposing sides of housing  12 . Strap  16  may be coupled to pins or other structures that are attached to the exterior of housing  12  (as an example). A clasp formed from hook-and-loop fasteners or other suitable clasp may be used to secure strap  16  about the wrist or other body part of a user. 
     Strap  16  may include strands of material that are woven together. The strands of material that are woven to form strap  16  may be monofilaments and/or multifilament yarns. Strap  16  may contain insulating strands of material and/or conductive strands of material. 
     Insulating strands may be formed from dielectric materials such as polymers. Conductive strands may be formed from metal wires or may be formed from one more conductive layers of material such as metal layers on polymer cores or other polymer layers. Conductive strands may also be formed by mixing conductive filaments with insulating filaments. Conductive strands may have insulating coatings. 
     If desired, strap  16  may contain electrical components such as components  20 . Components  20  may include sensors, buttons, light-emitting diodes, batteries, antennas, integrated circuits, vibrators and other actuators, and/or other input-output devices. Conductive strands of material such as strands  18  may be used in routing power and data signals between components  20  within strap  16  and between components such as component  20  in strap  16  and circuitry in housing  12 . 
     A schematic diagram of an illustrative electronic device such as device  10  of  FIG.  1    is shown in  FIG.  2   . As shown in  FIG.  2   , device  10  may include control circuitry  22 . Control circuitry  22  may include processing circuitry such as microprocessors, digital signal processors, microcontrollers, baseband processors, image processors, application-specific integrated circuits with processing circuitry, and/or other processing circuitry and may include random-access memory, read-only memory, flash storage, hard disk storage, and/or other storage (e.g., a non-transitory storage media for storing computer instructions for software that runs on control circuitry  22 ). 
     Device  10  may include electrical components in housing  12  and/or in strap  16  that form input-output circuitry such as input-output devices  24 . Input-output devices  24  may be used to allow data to be supplied to device  10  from external devices and from a user and to allow data to be provided from device  10  to external devices and the user. Input-output devices  24  may include buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, speakers, tone generators, vibrators, haptic devices, cameras, light-emitting diodes and other status indicators, displays such as display  14 , data ports, etc. Sensors  26  of input-output devices  24  may include touch sensors, force sensors, accelerometers, compasses, magnetic sensors, gas sensors, pressure sensors, temperature sensors, capacitive proximity sensors, light-based proximity sensors, digital image sensors, ambient light sensors, heart rate sensors and blood oxygen sensors (e.g., sensors having a light emitter that emits light into a user&#39;s skin and the detects and processes reflected light), and other sensing circuits. 
     Device  10  may include wireless circuitry (e.g., wireless transceivers, antennas, etc.) for supporting wireless local area network communications, cellular telephone communications, near field communications, wireless power transmission and reception operations, and other wireless communications and power transfer operations. 
     A cross-sectional side view of an illustrative device such as device  10  of  FIG.  1    is shown in  FIG.  3   . As shown in  FIG.  3   , strap  16  may have an outer surface (front side) such as outer surface  28  and may have an opposing inner surface (rear side) such as inner surface  30 . A clasp for strap  16  may be formed using magnets, interlocking prongs and holes, snaps, or other clasp mechanisms. With one illustrative configuration, which is shown in  FIG.  3   , strap  16  has a clasp formed from mating hook-and-loop fasteners. Portion  30 H of inner surface  30  of strap  16  may have hooks  32  and at least portion  28 L on the outer surface of strap  16  may have mating loops. If desired, most or all of outer surface  28  of strap  16  may have loops (e.g., so that outer surface  28  has a uniform appearance). 
     As shown in  FIG.  4   , when strap  16  is wrapped around a user&#39;s wrist or other body part such as wrist  34 , hooks  32  engage the loops of portion  28 L and thereby close the hook-and-loop fastener formed from hooks  32  and the loops of portion  28 L. When it is desired to open the clasp formed from the hook-and-loop fastener of strap  16 , a user may pull outwardly on the end of strap  16  that is adjacent to hooks  32 , thereby pulling hooks  32  away from the mating loops on portion  28 L of strap  16 . 
     The loops that are formed in region  28 L of surface  28  may, if desired, be formed from portions of the strands of material that are woven to form strap  16  (i.e., the strands of material that are used in forming strap  16  may have portions that extend outwardly from the rest of the fabric forming strap  16  so that these loop portions may be engaged by hooks  32 ). Hooks  32  may be individually incorporated into strand  16  or may be mounted on a fabric strip or other support layer that is attached to strap  16  with adhesive, by sewing, by welding (e.g., laser welding), by intertwining the strands of material that form strap  16  with hooks  32 , by crimping hooks  32  to strap  16 , by molding hooks  32  to strap  16 , or by using other suitable attachment mechanisms. Hooks  32  may be formed from metal, from plastic, from portions of the strands of material in fabric  16 , or from other suitable materials. 
     The fabric that forms strap  16  may have one or more stretchable layers. Consider, as an example, the illustrative fabric of  FIG.  5 A . Fabric  36  has strands  38  such as weft strands  38 A and warp strands  38 B. Warp strands  38 B (and, if desired, some or all of weft strands  38 A) may be formed from stretchable material such as stretchable polyurethane, spandex, silicone, or other stretchable material. Due to the presence of stretchable warp strands  38 B, fabric  36  may stretch when pulled in directions  42 , as illustrated in  FIG.  5 B . Stretchable strands such as warp strands  38 B may be oriented to run around the user&#39;s wrist (i.e., the warp strands in straps  16  may be oriented so that they extend along the elongated longitudinal dimension of strap  16 ). This allows a user to stretch strap  16  tightly around wrist  34  or other body part (e.g., to ensure that a satisfactory heart rate monitor signal is picked up by a heart rate monitor in device  10 , etc.). If desired, the fabric forming strap  16  may contain non-stretchable strands of material (e.g., polyester, etc.). Non-stretchable strands of material may, for example, be used to provide strap  16  with strength and/or moisture management capabilities. 
     Illustrative examples of stretchable strands that may be used in fabric such as fabric  36  of strap  16  are shown in  FIGS.  6 ,  7 ,  8 ,  9 ,  10 , and  11   . 
     In the example of  FIG.  6   , stretchable strand  38  is formed from a bundle of elastic strands  50  covered in a non-elastic material such as non-elastic material  52 . Each elastic strand  50  may be formed from elastic material such as natural rubber, synthetic rubber, nitrile rubber, silicone rubber, urethane rubbers such as polyurethane, spandex, chloroprene rubber, ethylene-vinyl acetate, polyolefin elastomer, polytrimethylene terephthalate, thermoplastic elastomers such as polyester-polyether copolymers, polyamide-polyether copolymers, other elastomers, other rubbers, and/or a combination of any two or more of these materials. There may be five, ten, fifteen, twenty, more than twenty, or less than twenty elastic strands  50  bundled in strand  38  of  FIG.  6   . 
     Non-elastic material  52  may be polyester or other non-stretchable material. Non-elastic material  52  may include one or more strands of material that are braided around elastic strands  50 , twisted (e.g., wrapped) around elastic strands  50 , or otherwise covering or partially covering the bundle of elastic strands  50 . If desired, non-elastic material  52  may be a coating rather than a strand (e.g., a coating that is deposited onto strand  38 , a coating that strand  38  is dipped into, or other suitable coating). 
     It can be challenging to incorporate strands that are sufficiently stretchable into a fabric that is worn against a user&#39;s skin. If there are too many elastic strands  50  bundled together in strand  38 , strand  38  may not be sufficiently stretchable. The elastic modulus (Young&#39;s modulus) of strand  38  of  FIG.  6    can be reduced by using fewer elastic strands  50  in strand  38 . However, fewer elastic strands  50  within strand  38  may lead to a reduced diameter D of strand  38 . If the diameter D of strand  38  is too small, fabric  36  that incorporates strands  38  may be uncomfortable for users because of the reduced surface area of strands  38  that is in contact with the user&#39;s skin. 
     To increase the elasticity of strands  38  without reducing the diameter of strands  38 , strands  38  may have a configuration of the type shown in  FIG.  7   . In the example of  FIG.  7   , stretchable strand  38  has a single elastic strand  50  at its core. Elastic strand  50  is covered with material  54 . Material  54  may be elastic material (e.g., natural rubber, synthetic rubber, nitrile rubber, silicone rubber, urethane rubbers such as polyurethane, spandex, chloroprene rubber, ethylene-vinyl acetate, polyolefin elastomer, polytrimethylene terephthalate, thermoplastic elastomers such as polyester-polyether copolymers, polyamide-polyether copolymers, other elastomers, other rubbers, and/or a combination of any two or more of these materials), may be non-elastic material (e.g., polyester, etc.), or may be a combination of elastic and non-elastic materials. Material  54  may include one or more strands of material that are twisted around elastic strand  50 , braided around elastic strand  50 , or otherwise covering or partially covering elastic strand  50 . If desired, material  54  may be a coating rather than a strand (e.g., a coating that is deposited onto strand  38 , a coating that strand  38  is dipped into, or other suitable coating). 
     Material  54  is configured to fill a space around elastic strand  50  to achieve the desired diameter D (e.g., a diameter that is equal or close to the diameter D of strand  38  of  FIG.  6   ). In some arrangements, material  54  may be one or more strands of non-elastic material that is twisted around elastic strand  50 . A twisted type of covering may be more stretchable than a braided layer. In this way, material  54  can be sufficiently thick to achieve the appropriate diameter D without compromising the stretchiness of strand  38 . 
     Material  54  may, if desired, consume most of the volume of strand  38 . The appropriate thickness of material  54  may be achieved by using a thick, low density material (e.g., a fuzzy material), using multiple layers of twisted coverings (e.g., one, two, three, or more than three covering layers), and/or selecting strands with an appropriate denier value (e.g., between 1,800 denier and 2000 denier or other suitable denier value). The thickness T 2  of material  54  may be greater than the diameter T 1  of elastic core  50 . 
       FIG.  8    shows an arrangement in which strand  38  includes a single elastic strand  50  at its core, a middle layer of material  54 , and an outer layer of material  56 . 
     Middle layer of material  54  may be elastic material (e.g., natural rubber, synthetic rubber, nitrile rubber, silicone rubber, urethane rubbers such as polyurethane, spandex, chloroprene rubber, ethylene-vinyl acetate, polyolefin elastomer, polytrimethylene terephthalate, thermoplastic elastomers such as polyester-polyether copolymers, polyamide-polyether copolymers, other elastomers, other rubbers, and/or a combination of any two or more of these materials), may be non-elastic material (e.g., polyester, etc.), or may be a combination of elastic and non-elastic materials. Material  54  may include one or more strands of material that are twisted around elastic strand  50 , braided around elastic strand  50 , or otherwise covering or partially covering elastic strand  50 . If desired, material  54  may be a coating rather than a strand (e.g., a coating that is deposited onto strand  38 , a coating that strand  38  is dipped into, or other suitable coating). 
     Outer layer of material  56  may be elastic material (e.g., natural rubber, synthetic rubber, nitrile rubber, silicone rubber, urethane rubbers such as polyurethane, spandex, chloroprene rubber, ethylene-vinyl acetate, polyolefin elastomer, polytrimethylene terephthalate, thermoplastic elastomers such as polyester-polyether copolymers, polyamide-polyether copolymers, other elastomers, other rubbers, and/or a combination of any two or more of these materials), may be non-elastic material (e.g., polyester, etc.), or may be a combination of elastic and non-elastic materials. Material  56  may include one or more strands of material that are braided around elastic strand  50  and middle layer of material  54 , twisted around elastic strand  50  and middle layer of material  54 , or otherwise covering or partially covering elastic strand  50  and middle layer of material  54 . If desired, material  56  may be a coating rather than a strand (e.g., a coating that is deposited onto strand  38 , a coating that strand  38  is dipped into, or other suitable coating). 
     In one illustrative arrangement, middle layer of material  54  is formed from one or more strands that are twisted around elastic strand  50 , and outer layer of material  56  is formed from one or more strands that are braided around elastic strand  50  and middle layer  54 . With this type of arrangement, middle layer of material  54  may be used to achieve the desired diameter of strand  38  (e.g., by consuming the bulk of the volume in strand  38 ), but may remain sufficiently stretchable due to the fact that the strands of material  54  are twisted around elastic strand  50 . Outer layer  56  may be used to impart a desired texture to the outer surface of strand  38  (and thus the outer surface of fabric  36 ), may be used to provide moisture-wicking (e.g., by using strands with different denier values than that of middle layer  54 ), may be used to provide electrical insulation (e.g., in arrangements where strand  38  has conductive portions that convey electrical signals), may serve as a moisture barrier, and/or may serve other purposes. 
     As in the example of  FIG.  7   , material  54  of  FIG.  8    is configured to fill a space around elastic strand  50  to achieve the desired strand diameter (e.g., a diameter that is equal or close to the diameter D of strand  38  of  FIG.  6   ). Material  54  may be sufficiently thick to achieve the appropriate diameter D without compromising the stretchiness of strand  38 . The thickness T 2  of the middle layer of material  54  may be greater than the thickness T 3  of outer layer of material  56  and may also be greater than the diameter T 1  of elastic core  50 . The appropriate thickness of material  54  may be achieved by using a thick, low density material (e.g., a fuzzy material), using multiple layers of twisted coverings (e.g., one, two, three, or more than three covering layers, such as covering layers  54 A and  54 B of  FIG.  11   ), and/or selecting strands with an appropriate denier value (e.g., between 1,800 denier and 2000 denier or other suitable denier value). 
     The example of  FIGS.  7  and  8    in which strand  38  includes only a single elastic strand  50  at its core is merely illustrative. If desired, strand  38  may include one, two, three, four, five, ten, more than ten, or less than ten elastic strands  50  at its core.  FIG.  9    shows an illustrative arrangement with three elastic strands  50  at the core of strand  38 . The three elastic strands  50  are covered with middle layer of material  54  (e.g., a covering formed from strands of material  54  that are twisted around elastic strands  50 ) and outer layer of material  56  (e.g., strands of material  56  that are braided around elastic strands  50  and middle layer of material  54 ). This example is merely illustrative. In general, strand  38  may include any suitable number of elastic strands  38  at its core. 
       FIG.  10    is a side view of an illustrative strand  38  with high elasticity (low Young&#39;s modulus) and a sufficiently large strand diameter. As shown in  FIG.  10   , strand  38  may have one or more elastic strands  50  at its core. Strands of material  54  may be twisted around elastic strand  50  (e.g., in a Z-twist direction or an S-twist direction). Strands of material  54  may have any suitable number of turns per meter (e.g., 1000 turns per meter, 1500 turns per meter, 2000 turns per meter, 2500 turns per meter, 3000 turns per meter, greater than 3000 turns per meter, less than 300 turns per meter, etc.). Strands of material  54  may be covered with a braided layer (e.g., as in the example of  FIGS.  8  and  9   ) or may be left uncovered (e.g., as in the example of  FIG.  7   ). 
     In the example of  FIG.  11   , strands of material  54  are used to form first and second coverings such as inner covering  54 A and outer covering  54 B. Inner covering  54 A and outer covering  54 B may have the same characteristics or may have different characteristics (e.g., may have different numbers of turns per meter, may be formed from different materials, may be twisted in different twist directions, may have different denier values to achieve a moisture-wicking effect, etc.). For example, inner covering  54 A may have a first twist direction (e.g., a Z-twist direction) and a first number of turns per meter (e.g., 2000 turns per meter) and outer covering  54 B may have a second twist direction (e.g., an S-twist direction) and a second number of turns per meter (e.g., 2000 turns per meter). This is, however, merely illustrative. In general, the layers of material  54  such as layers  54 A and  54 B may have any suitable twist direction and any suitable number of turns per meter (e.g., 1000 turns per meter, 1500 turns per meter, 2000 turns per meter, 2500 turns per meter, 3000 turns per meter, greater than 3000 turns per meter, less than 300 turns per meter, etc.). 
     Strands of material  54  may be covered with a braided layer (e.g., as in the example of  FIGS.  8  and  9   ) or may be left uncovered (e.g., as in the example of  FIG.  7   ). 
     The example of  FIG.  11    in which material  54  forms two covering layers is merely illustrative. If desired, layers of material  54  may form three, four, more than four, or less than four layers of covering on elastic strand  50  at the core of strand  38 . 
     With fewer elastic strands  50  in strand  38  (e.g., strand  38  of  FIGS.  7 ,  8 ,  9 ,  10 , and  11   ), strand  38  may have a lower Young&#39;s modulus than strand  38  of  FIG.  6    while still maintaining a sufficiently large strand diameter. The elasticity of strand  38  can be modified by changing the number of elastic strands  50  at the core of strand  38 , changing the diameter of elastic strands  50  at the core of strand  38 , changing the number of layers of material  54 , changing the types of materials used for strands  50 ,  54 , and/or  56 , changing the denier value of strands  50 ,  54 , and/or  56 , etc. 
     The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20190828
Publication Date: 20230919
Grant Date: 20230919
Priority Date: 20180913
Inventors: HEGDE, SIDDHARTHA
BHATIA, RIMPLE
HAMADA, Yohji
WALKER, JOSEPH B.
Assignee: APPLE INC
CPC Classifications: [{"code": "A44C5/0053", "inventive": true, "first": true, "tree": "[]"}, {"code": "D10B2401/061", "inventive": false, "first": false, "tree": "[]"}, {"code": "D10B2331/04", "inventive": false, "first": false, "tree": "[]"}, {"code": "D02G3/32", "inventive": true, "first": false, "tree": "[]"}, {"code": "A44C5/0053", "inventive": true, "first": true, "tree": "[]"}, {"code": "D02G3/32", "inventive": true, "first": false, "tree": "[]"}, {"code": "D10B2331/04", "inventive": false, "first": false, "tree": "[]"}, {"code": "A44C5/0053", "inventive": true, "first": true, "tree": "[]"}, {"code": "D02G3/32", "inventive": true, "first": false, "tree": "[]"}, {"code": "D10B2331/04", "inventive": false, "first": false, "tree": "[]"}, {"code": "D10B2401/061", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 88067858