PATENT DOCUMENT

Publication Number: US-11530501-B1
Application Number: US-201815947679-A
Country: US
Kind Code: B1

Title: Tubular warp knit spacer fabric

Abstract:
A warp knitting system may knit a seamless tube of fabric. The fabric may have a spacer between outer and inner fabric layers. The knitting system may have first and second needle guide systems. The first and second needle guide systems may each have selectively linked needle bed sections that guide respective needles. A guide bar system may have guide bars that dispense strands of material during knitting. Each guide bar may be positioned using a respective guide bar positioner. The guide bar system may be shifted relative to the needles using a rotational positioner. The needle guide systems and guide bar system may be formed from selectively coupled links. The selectively coupled links may be configured to adjust the diameter of the tube of fabric to a desired value. The thickness of the tube may be adjusted by adjusting a gap between the first and second needle guide systems.

Claims:
What is claimed is: 
     
       1. A fabric-based item comprising:
 a housing having a sidewall surface and an upper surface; 
 a seamless tube of warp knit fabric having an inner warp knit layer and an outer warp knit layer and having a warp knit spacer layer between the inner and outer warp knit layers that is alternately coupled to inner stitch rows in the inner warp knit layer and outer stitch rows in the outer warp knit layer, wherein each inner stitch row and outer stitch row to which the spacer layer is coupled are separated by at least one row of stitches, and wherein the seamless tube of warp knit fabric covers the sidewall surface and a portion of the upper surface; and 
 electrical components mounted in the housing. 
 
     
     
       2. The fabric-based item defined in  claim 1  wherein the electrical components include a speaker and wherein the seamless tube of warp knit fabric forms a covering layer that is permeable to sound and that surrounds the speaker, wherein the warp knit spacer layer is formed from warp knit monofilaments, and wherein the inner and outer warp knit layers are formed from warp knit multifilament yarns. 
     
     
       3. The fabric-based item defined in  claim 2  wherein the seamless tube of warp knit fabric includes an array of openings. 
     
     
       4. The fabric-based item defined in  claim 3  further comprising a cylindrical support structure covered by the seamless tube of warp knit fabric. 
     
     
       5. The fabric-based item defined in  claim 1  wherein the warp knit spacer layer is formed from warp knit monofilaments. 
     
     
       6. The fabric-based item defined in  claim 1  wherein the inner and outer warp knit layers are formed from warp knit multifilament yarns and wherein the electrical components comprise wireless communications circuitry. 
     
     
       7. The fabric-based item defined in  claim 1  wherein the seamless tube of warp knit fabric has a circular cross-sectional profile. 
     
     
       8. The fabric-based item defined in  claim 7  wherein the inner warp knit layer has a first stitch size and wherein the outer warp knit layer has a second stitch size that is greater than the first stitch size. 
     
     
       9. The fabric-based item defined in  claim 1  wherein the seamless tube of warp knit fabric has a cross-sectional profile with a corner portion and a planar portion. 
     
     
       10. The fabric-based item defined in  claim 9  wherein the inner warp knit layer has a first stitch size at the planar portion and a second stitch size at the corner portion, wherein the outer warp knit layer has the first stitch size at the planar portion and a third stitch size at the corner portion, and wherein the first stitch size is greater than the second stitch size and the third stitch size is greater than the first stitch size. 
     
     
       11. The fabric-based item defined in  claim 1  wherein the inner and outer warp knit layers are formed from strands formed from a material selected from the group consisting of polymer, metal, glass, graphite, ceramic, cotton and bamboo. 
     
     
       12. The fabric-based item defined in  claim 1  wherein the inner and outer warp knit layers are formed from strands formed from non-conductive material coated with conductive material. 
     
     
       13. The fabric-based item defined in  claim 1  wherein the seamless tube of warp knit fabric is bent along a longitudinal axis to form a C-shaped cross section. 
     
     
       14. The fabric-based item defined in  claim 1  wherein the warp knit spacer layer is formed from multifilament strands coupled to loops. 
     
     
       15. A fabric-based item, comprising:
 a seamless tube of warp knit fabric, comprising:
 an inner warp knit layer with a first diameter formed from a first stitch size; 
 an outer warp knit layer with a second diameter formed from a second stitch size, wherein the second diameter is larger than the first diameter and the second stitch size is larger than the first stitch size; and 
 a warp knit spacer layer between the inner and outer warp knit layers that is alternately coupled to the inner warp knit layer and the outer warp knit layer; and 
 
 electrical circuitry. 
 
     
     
       16. The fabric-based item defined in  claim 15  further comprising a support structure covered by the seamless tube of warp knit fabric, wherein the electrical circuitry is mounted within the support structure. 
     
     
       17. The fabric-based item defined in  claim 16  wherein the electrical circuitry comprises wireless communications circuitry. 
     
     
       18. A fabric-based item comprising:
 a seamless tube of fabric having an inner warp knit layer and an outer warp knit layer and having a warp knit spacer layer between the inner and outer warp knit layers that is alternately coupled to loops in the inner warp knit layer and loops in the outer warp knit layer, wherein the seamless tube of fabric has an upper portion, a lower portion, and sidewall portions that extend from the upper portion to the lower portion, wherein the sidewall portions have first and second regions, wherein the inner warp knit layer has a first stitch size at the first region and a second stitch size at the second region, wherein the outer warp knit layer has the first stitch size at the first region and a third stitch size at the second region, and wherein the first stitch size is greater than the second stitch size and the third stitch size is greater than the first stitch size; and 
 a speaker interposed between the upper portion and the lower portion. 
 
     
     
       19. The fabric-based item defined in  claim 18  further comprising a plastic support structure covered by the seamless tube of warp knit fabric, wherein the speaker is mounted in the plastic support structure. 
     
     
       20. The fabric-based item defined in  claim 19  wherein the seamless tube of warp knit fabric is permeable to sound and has a circular cross-sectional profile.

Description:
This patent claims the benefit of provisional patent application No. 62/567,118, filed on Oct. 2, 2017, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to fabric and, more particularly, to systems for forming warp knit fabric and devices that include warp knit fabric. 
     BACKGROUND 
     It may be desirable to form voice-controlled assistant devices, bags, covers for electronic devices such as cellular telephones and tablet computers, and other equipment from fabric. Fabric-based items such as these may have an attractive appearance and may benefit from desirable attributes associated with fabric such as sound permeability, light weight, and durability. 
     In some arrangements, knit fabric may have an appearance and other attributes that are preferred over woven fabric. It may be easier and faster to produce warp knit fabric than weft knit fabric, so applications involving knit fabric often rely on warp knit fabric. 
     It can be challenging, however, to produce warp knit fabric with desired characteristics. 
     SUMMARY 
     A fabric-based item such as an electronic device having a housing covered with fabric may include a seamless tube of warp knit fabric. A warp knitting system may knit the seamless tube of fabric. The fabric may have a spacer between outer and inner fabric layers. The fabric may be used as a covering for an electronic device, may be used as part of a bag or enclosure, or may form a portion of other fabric-based items. 
     The knitting system may have first and second needle guide systems. The needle guide systems may each have needle bed sections that guide respective needles. Each needle may have a positioner that is individually adjustable. A guide bar system may have guide bars that dispense strands of material during knitting. Each guide bar may be positioned using a respective guide bar positioner. During knitting, the guide bar system may be shifted relative to the needles using a rotational positioner. 
     The needle guide systems and guide bar system may be formed from selectively coupled sections. The selectively coupled sections may be configured to adjust the diameters of the guide bar systems and the needle guide systems and thereby adjust the diameter of the tube of fabric to a desired value. The thickness of the tube may be adjusted by adjusting a gap between the first and second needle guide systems. Other aspects of the fabric tube such as the cross-sectional profile of the tube and bends in the tube along the tube&#39;s longitudinal axis may also be adjusted by controlling the warp knitting process. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of an illustrative fabric-based item such as a voice-controlled electronic device having a housing covered with a fabric layer in accordance with an embodiment. 
         FIG.  2    is a schematic diagram of an illustrative warp knitting system in accordance with an embodiment. 
         FIG.  3    is a diagram of a portion of an illustrative layer of warp knit fabric in accordance with an embodiment. 
         FIG.  4    shows how a layer of fabric may have openings such as diamond-shaped openings in accordance with an embodiment. 
         FIG.  5    is a perspective view of an illustrative warp knitting system in accordance with an embodiment. 
         FIG.  6    is a side view of an illustrative adjustable guide system for a warp knitting system in accordance with an embodiment. 
         FIG.  7    is a top view of an illustrative guide system and an associated needle system in a warp knitting system in accordance with an embodiment. 
         FIGS.  8  and  9    show illustrative needles and positioners for moving the needles in accordance with an embodiment. 
         FIG.  10    is a top view of a portion of a needle bed in an illustrative needle system in accordance with an embodiment. 
         FIG.  11    is a side view of the illustrative needle bed of  FIG.  10    in accordance with an embodiment. 
         FIG.  12    is an end view of an illustrative set of needles showing illustrative guide bar paths around the needles in accordance with an embodiment. 
         FIG.  13    is a perspective view of an illustrative knitting system in accordance with an embodiment. 
         FIG.  14    is a side view of an illustrative knitting system in accordance with an embodiment. 
         FIG.  15    is a top view of illustrative seamless tubular fabric having an internal spacer layer that separates inner and outer knit fabric layers from each other in accordance with an embodiment. 
         FIG.  16    is a top view of an illustrative knitting system configured to exhibit a circular outline in accordance with an embodiment. 
         FIG.  17    is a top view of the illustrative knitting system of  FIG.  16    that has been reconfigured to enhance its size (diameter) by incorporating additional sections in accordance with an embodiment. 
         FIG.  18    is a top view of a portion of a guide and a portion of a needle bed in accordance with an embodiment. 
         FIG.  19    is a side view of an illustrative tube of fabric in accordance with an embodiment. 
         FIGS.  20 ,  21 , and  22    are cross-sectional views of illustrative tubes of fabric in accordance with embodiments. 
         FIGS.  23 ,  24 ,  25 , and  26    are cross-sectional side views of illustrative tubes of fabric with fabric layers that have been configured to produce bends in the cross-sectional profiles of the tubes in accordance with embodiments. 
         FIG.  27    is a perspective view of an illustrative warp knitted fabric structure in accordance with an embodiment. 
         FIG.  28    is a cross-sectional side view of a tube of fabric of the type that may be configured to form a spiral tube in accordance with an embodiment. 
         FIG.  29    is an illustrative spiral tube of fabric in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Items such as item  10  of  FIG.  1    may be based on fabric. Item  10  may be an electronic device or an accessory for an electronic device such as a voice-controlled electronic device (sometimes referred to as a digital assistant or voice-controlled speaker), a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wristwatch device, a pendant device, a headphone or earpiece device, a device embedded in eyeglasses or other equipment worn on a user&#39;s head, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which fabric-based item  10  is mounted in a kiosk, in an automobile, airplane, or other vehicle, other electronic equipment, or equipment that implements the functionality of two or more of these devices. If desired, item  10  may be a removable external case for electronic equipment, may be a strap, may be a wrist band or head band, may be a removable cover for a device, may be a case or bag that has straps or that has other structures to receive and carry electronic equipment and other items, may be a necklace or arm band, may be a wallet, sleeve, pocket, or other structure into which electronic equipment or other items may be inserted, may be part of a chair, sofa, or other seating (e.g., cushions or other seating structures), may be part of an item of clothing or other wearable item (e.g., a hat, belt, wrist band, headband, shirt, pants, shoes, etc.), or may be any other suitable fabric-based item. In the illustrative configuration of  FIG.  1   , item  10  is a voice-controlled electronic device such as a voice-controlled speaker with internet access. Other types of device may incorporate fabric, if desired. 
     As shown in  FIG.  1   , item  10  may include a housing such as housing  12 . Housing  12  may have a cylindrical shape of the type shown in  FIG.  1    or other suitable shape (e.g., a pyramidal shape, a conical shape, a box shape such as a rectangular box shape, a spherical shape, etc.). Housing  12  may include support structures formed from metal, polymer, ceramic, glass, wood, other materials, and/or combinations of these materials. Item  10  may include fabric  14 . Fabric  14  may form all or part of a housing wall or other layer in an electronic device, may form internal structures in an electronic device, or may form other fabric-based structures. Item  10  may be soft (e.g., item  10  may have a fabric surface that yields to a light touch), may have a rigid feel (e.g., the surface of item  10  may be formed from a stiff fabric), may be coarse, may be smooth, may have ribs or other patterned textures, and/or may be formed as part of a device that has portions formed from non-fabric structures of plastic, metal, glass, crystalline materials, ceramics, or other materials. For example, some or all of the upper surface of housing  12 , the sidewall surfaces of housing  12 , surfaces associated with lower portions of housing  12 , and/or other portions of item  10  may be covered with fabric  14 . In some configurations, fabric  14  may serve as a cosmetic cover for item  10  that is permeable to sound. 
     Fabric  14  may include intertwined strands of material such as strands  16 . Fabric  14  may, for example, be warp knit fabric that is formed by warp knitting of strands  16 . Strands  16  may be single-filament strands (sometimes referred to as fibers or monofilaments) or may be strands of material formed by intertwining multiple monofilaments of material together (sometimes referred to as yarns). 
     Strands  16  may be formed from polymer, metal, glass, graphite, ceramic, natural materials such as cotton or bamboo, or other organic and/or inorganic materials and combinations of these materials. Conductive coatings such as metal coatings may be formed on non-conductive material. For example, plastic strands in fabric  14  may be coated with metal to make them conductive. Reflective coatings such as metal coatings may be applied to make strands reflective. Strands may be formed from bare metal wires or metal wire intertwined with insulating monofilaments (as examples). Bare metal strands and strands of polymer covered with conductive coatings may be provided with insulating polymer jackets. 
     Items such as item  10  may, if desired, include control circuitry  20 . Control circuitry  20  may include microprocessors, microcontrollers, application-specific integrated-circuits, digital signal processors, baseband processors, and/or other controllers and may include storage such as random-access memory, read-only memory, solid state drives, and/or other storage and processing circuitry. 
     Control circuitry  20  may gather information from sensors and other circuitry in input-output devices  18  and may use input-output devices  18  to supply output. Input-output devices  18  may, for example, include audio devices such as microphones and speakers. Microphones can gather audio input (e.g., sound that passes through fabric  14 ). Speakers can produce audio output (e.g., sound that passes through fabric  14 ). Sensors in input-output devices  18  may include touch sensors, force sensors, capacitive sensors, optical sensors, proximity sensors, strain gauges, temperature sensors, moisture sensors, gas sensors pressure sensors, magnetic sensors, position and orientation sensors (e.g., accelerometers, gyroscopes, and/or compasses), and/or other sensors. Light-emitting diodes, displays, and other visual output devices may be used in supply visual output to a user. Buttons, joysticks, haptic output components, and/or other input-output components may be provided in input-output devices  18  to gather input from a user and to provide a user with output. Wireless circuitry in circuitry  20  (e.g., wireless local area network circuitry, cellular telephone circuitry, etc.) may be used to support wireless communications with external equipment. 
     Integrated circuits and other electrical components forming circuitry  20  and/or input-output devices  18  may be mounted in housing  12 . Fabric  14  may cover the exterior of housing  12  (e.g., to hide electrical components in housing  12  from view). Fabric  14  may also be used in forming structural portions of housing  12  and/or other portions of item  10 , may be used in forming straps, covers, wearable items, and/or other structures for items  10 . 
     A warp knitting machine or other equipment may be used in forming fabric  14  from strands  16 .  FIG.  2    is a schematic diagram of an illustrative warp knitting system. As shown in  FIG.  2   , yarn source  32  in warp knitting system  30  may be used in supplying strands  16  to guide and needle structures  34 . Structures  34  may include strand guide structures (e.g., a system of movable guide bars with eyelets that guide strands  16 ) and needle systems (e.g., needle guide systems that guide sets of individually adjustable needles so that the needles may interact with the strands dispensed by the guide bars). During operations, a controller may control electrically adjustable positioners in system  30  to manipulate the positions of guide bars and needles in system  30  and thereby knit strands  16  into fabric  14 . Take down  36  (e.g., a pair of mating rollers or other equipment forming a take down system) may be used to gather fabric  14  that is produced during knitting. 
     A layer of illustrative warp knit fabric  14  is shown in  FIG.  3   . An illustrative strand  16 ′ among strands  16  has been highlighted to show the zig-zag path taken by each strand in fabric  14 . 
     During knitting, control circuitry in system  30  may direct electrically adjustable positioners in system  30  to knit fabric  16  with any suitable warp knit pattern. As an example, control circuitry in system  30  may use the electrically adjustable positioners to knit fabric  16  that includes diamond-shaped openings or openings of other suitable shapes, as illustrated by openings  38  in warp knit fabric  14  of  FIG.  4   . 
       FIG.  5    is a perspective view of an illustrative warp knitting system. As shown in  FIG.  5   , warp knitting system may have first portion  30 - 1  and second portion  30 - 2 . Portions  30 - 1  and  30 - 2  may have first and second support structures (first and second needle guide systems) for respectively supporting first and second sets of needles  42 . These support structures, which may sometimes be referred to as needle beds, needle guide structures, needle guides, or needle systems, may have conical shapes as shown in  FIG.  5    (e.g., to help avoid interference between opposing needles  42 ) or may have other suitable shapes, (e.g., cylindrical shapes, cylindrical shapes with planar inserted sections, etc.). Portion  30 - 1  may support any suitable numbers of needles  42  around its periphery (e.g., 10s of needles, 100s of needles, or more). As an example, portion  30 - 1  may support 100-400 needles, at least 50 needles, at least 200 needles, fewer than 500 needles, etc. Portion  30 - 2  may support the same number of needles  42  as portion  30 - 1  (as an example). Only a single needle  42  is shown on portion  30 - 1  and only a single needle  42  is shown on portion  30 - 2  to avoid over-complicating the diagram. 
     Guide bar system  40 , which may sometimes be referred to as a strand guide system, yarn guide system, guide bar system, or strand guiding system, may include a series of guide bars that are used in providing needles  42  with strands  16 . Needles  42  may be moved using electrically adjustable positioners  44 . The guide bars may be positioned using adjustable guide bar positioners. Guide bar system  40  may also be rotated about axis Z relative to portions  30 - 1  and/or  30 - 2  by an adjustable rotational angle A using a rotational positioner. The separation (gap G) between portions  30 - 1  and  30 - 2  can be adjusted by moving portions  30 - 1  and  30 - 2  relative to each other along axis Z (e.g., using a positioner such as electrically adjustable longitudinal axis positioner  48 , which can be used in adjusting the position of portion  30 - 2  along axis Z (e.g., the longitudinal axis of system  30 ). 
     The positioners in system  30  such as positioners  44  for positioning needles  42  and the guide bar positioners in guide bar system  40  may be controlled dynamically by control circuitry such as controller  46 . Each needle  42  may have a respective individually adjustable positioner  44  to provide system  30  with Jacquard capabilities and/or sets of two or more needles  42  may be adjusted together (e.g., to reduce the number of individually adjustable positioners that are used). In some configurations, for example, all of needles  42  on portion  30 - 1  may be adjusted together and all of needles  42  on portion  30 - 2  may be adjusted together. The ability of each of positioners  44  to be independently controlled by controller  46  allows each of needles  42  to be moved independently, thereby allowing fabrics with a variety of different designs to be formed. 
       FIG.  6    is a cross-sectional side view of a portion of guide bar system  40  taken at a particular location around the periphery of system  30  (e.g., in the X-Z plane of  FIG.  5   ). As shown in  FIG.  6   , at each angular position (e.g., each needle position) around the periphery of system  30 , guide bar system  40  may have a set of multiple guide bars  50  supported using guide bar support structure  52 . Each guide bar  50  may have an eyelet  59 . Strands  16  may pass through eyelets  59 . During operation, the position of eyelets  59  and therefore strands  16  may be adjusted dynamically (e.g., to wrap strands  16  about desired needles  42 , etc.). 
     There may be N pairs of needles  42  at N different angular locations (values of angle A) around the Z axis and N corresponding sets of guide bars  50 . There may be 2-16 guide bars  50  in each set of guide bars  50 , 4-12 guide bars  50  in each set, 8-16 guide bars  50  in each set, at least 4 guide bars  50  in each set, at least 8 guide bars  50  in each set, fewer than 16 guide bars  50  in each set, etc. Each guide bar  50  may be coupled to a respective electrically adjustable guide bar positioner  54 . By adjusting the guide bar positioner for a given guide bar, the angular orientation of that guide bar within its plane of rotation may be adjusted. For example, a guide bar may be moved upwards in direction  56  or downwards in direction  58 . Movement along the periphery of system  30  may be controlled by rotating guide bar system  40  around axis Z. 
     Consider, as an example, the top view of guide bar system  40  that is shown in  FIG.  7   . As shown in  FIG.  7   , guide bars  50  may be distributed around the interior of guide bar support  52  and may face inwardly towards the Z axis. Needles  42  may have tips with hooks located in ring-shaped region  42 R. Region  42 R may be overlapped by tips  50 ′ of guide bars  50 . As shown in  FIG.  7   , the angular position of each guide bar  50  around axis Z can be adjusted by adjusting the angular position of guide bar support  52  around axis Z (e.g., by rotating guide bar support  52  and therefore guide bars  50  using guide bar system rotational positioner  60 ). 
     Needles  42  may have any suitable configuration. Illustrative latch needles (needles having hooks with latches such as hooks  42 H) are shown in  FIGS.  8  and  9   . In the example of  FIG.  8   , needle positioner  44  includes cam  44 C and electrically adjustable positioner  44 A. Needle  42  of  FIG.  8    can be moved in direction  62  by moving cam  44 C against butt  42 B of needle  42  with positioner  44 A. In the example of  FIG.  9   , needle  42  has magnet  42 M. Needle positioner  44  includes electrically controlled electromagnet  44 E and electrically adjustable positioner  44 A. Needle  42  may be moved in direction  62  by activating electromagnet  44 E and moving electromagnet  44 E in direction  62  with positioner  44 A. 
     Coupling structures  45  may be used to couple positioner  44 A to latch needle positioning structures such as cam  44 C of  FIG.  8    and movable electromagnet  44 E. In general, any suitable coupling mechanism may be used in forming coupling structures  45  (e.g., pushrods, levers, moving wheels, gears with teeth, etc.). With one illustrative configuration, coupling structures  45  are formed from cables such as metal cables that slide in polymer sheaths, allowing actuators such as positioners  44 A to be located away from needles  42 . If desired, guiding structures such as pulleys can be used to help guide the cables. The cables can be any suitable length (e.g., at least 10 cm, at least 100 cm, at least 1000 cm, less than 500 cm, less than 40 cm, etc.). By using cables to form coupling structures  45 , the lengths of the needles may be shortened and the diameter of the system can be reduced. 
       FIG.  10    is an end view of an illustrative needle bed (sometimes referred to as a needle guide or needle guide structure). As shown in  FIG.  10   , needle bed  66  may have a series of needle guides  64  (sometimes referred to as needle guide grooves, needle guide slots, or needle tricks).  FIG.  11    is a front view of the illustrative needle bed  66  of  FIG.  10   , showing how needles  42  may each lie within a respective one of the needle guide grooves  66 . During operation (e.g., when needle positioner  44  is activated), the hooked ends of needles  42  may extend outwardly from needle bed  66  in direction  62  to engage strands  16  being provided by guide bars  50 . 
     Illustrative operations associated with dispensing a strand from a guide bar onto a needle is shown in  FIG.  12   . In a first scenario, strand  16  is moved around one of needles  42  following path  70 . In a second scenario, strand  16  is moved around multiple needles  42  following path  74 . 
     Consider, as an example, the first scenario. In this arrangement, the guide bar holding strand  16  initially has its eyelet  59  at start position  68 . The guide bar positioner  54  for that guide bar  50  is then used to move eyelet  59  of that guide bar  50  upwards in direction  56  (e.g., in the +Z direction). This is followed by movement of guide bar  50  and its eyelet  59  to the right (in the +Y direction) by rotating guide bar support  52  with guide bar system rotational positioner  60  (e.g., by increasing rotational angle A). Guide bar positioner  54  may then move eyelet  59  downwards in direction  58  (e.g., in the —Z direction). Guide bar system  40  may then be rotated in the reverse direction (by using positioner  60  to rotate support  52  to decrease rotational angle A). As shown in  FIG.  12   , this moves strand  16  to position  72  at the end of path  70 . Similar motions may be used in the second scenario to move strand  16  from position  68  to position  72  around three different needles  42  following path  74 . Other strand movements may be achieved by dynamically adjusting strand guide bar system  40  with controller  46 , if desired. The examples of  FIG.  12    are illustrative. 
       FIG.  13    is a perspective view of a portion of system  30 . As shown in  FIG.  13   , needles  42  may be guided by needle guide grooves  64  in needle beds  66 . Guide bars  50  may be selectively arranged to align with lines such as lines  50 L. During operation, a tube of knit fabric may pass through gap G between the needle guide system of portion  30 - 1  and the opposing needle guide system of portion  30 - 2  and be guided downwards through the center of system  30  (e.g., through an opening in the needle guide system of portion  30 - 2 ) using rollers such as roller  76 . 
     The side view of system  30  of  FIG.  14    shows how a seamless tubular fabric with a spacer layer may be warp knitted using system  30 . As shown in  FIG.  14   , fabric  14  may include outer fabric layer  14 - 2  formed by needles  42  associated with outer (first) portion  30 - 1  of system  30  and may include inner fabric layer  14 - 1  formed by needles  42  associated with inner (second) portion  30 - 2  of system  30 . Spacer strands  16 ″ may be formed from monofilament (e.g., polymer monofilament fibers) and/or other strands of material. Each spacer strand  16 ″ may be coupled alternately to one or more inner fabric layers such as inner fabric layer  14 - 1  and one or more outer fabric layers such as outer fabric layer  14 - 2 . 
     As an example, as fabric  14  is being knit, a given spacer strand  16 ″ may be coupled to a row of stiches in inner fabric layer  14 - 1 . After additional rows of stiches have been formed in the inner fabric layer  14 - 1  (without coupling spacer strand  16 ′ to those stitches), the spacer strand  16 ′ may be coupled to a row of stitches in outer fabric layer  14 - 2 . In this way, spacer strand  16 ′ may oscillate back and forth between inner fabric layer  14 - 1  and outer fabric layer  14 - 2  to form a cushioning interior spacer layer in fabric  14 . This provides fabric  14  with a soft cushioning feel when touched by the hand of a user (e.g., when a user picks up item  10  or otherwise interacts with item  10 ). At the same time, the circular symmetry of system  10  allows fabric  14  to be provided to take down system  36  as a continuous seamless tube of fabric. This tubular fabric, which may sometimes be referred to as a spacer fabric due to the presence of the spacer layer between outer layer(s)  14 - 2  and inner layer(s)  14 - 1 , may be used as a fixed or removable cylindrical sleeve for an item with a cylindrical housing such as illustrative item  10  of  FIG.  1    and/or may be incorporated into other fabric-based items. 
     A top view of seamless warp knit tubular spacer fabric  14  is shown in  FIG.  15   , which shows how each spacer strand  16 ″ alternated between being attached to a loop in outer fabric layer  14 - 2  and inner fabric layer  14 - 1 . The thickness of fabric  14  between layers  14 - 1  and  14 - 2  (e.g., spacer thickness) can be adjusted by adjusting the magnitude of gap G between the needle systems of portions  30 - 1  and  30 - 2  in system  30  (see, e.g.,  FIG.  5   ). If G is larger, fabric  14  will be thicker. If G is smaller, fabric  14  will be thinner. 
       FIGS.  16  and  17    show how selected sections of needle beds  66  and guide bar system  40  may be configured to form a knitting system of different sizes to produce fabric tubes of corresponding different diameters. In the example of  FIG.  16   , two circular half portions  30 L and  30 R of system  30  have been assembled along dividing line  80  to form a circular warp knitting system of the type shown in  FIG.  5   . In the example of  FIG.  17   , additional sections of system  30  have been added to enlarge the lateral dimensions of system  30  (e.g., to add more needles  42  and more corresponding guide bars  50  to enlarge system core diameter CD as shown in  FIG.  14   ) and thereby enlarge the lateral dimensions (e.g., the tube diameter) of fabric tube  14 . In general, any suitable number of additional sections may be added to system  30  (e.g., a first pair of sections  30 P 1  and  30 P 5  between lines  80 - 1  and  80 - 2 , a second pair of sections  30 P 2  and  30 P 6  between lines  80 - 2  and  80 - 3 , a third pair of sections  30 P 3  and  30 P 7  between lines  80 - 3  and  80 - 4 , and/or a fourth pair of sections  30 P 4  and  30 P 8  between lines  80 - 4  and  80 - 5 ). Added sections may be straight and/or may be curved. 
       FIG.  18    shows an illustrative configuration for accommodating additional sections of system  30 . In the example of  FIG.  18   , guide bars  50  are supported by a segmented guide bar support structures (guide bar support links  52 L) and needles  42  are supported by corresponding segmented needle bed structures (needle bed links  66 L). Each section of guide bar system  40  such as link  52 L may be coupled to multiple sets of guide bars  50 . Each needle guide section such as needle guide link  66 L may contain a corresponding set of needles  42 . Links  66 L may include a first set of links for supporting needles  42  in portion  30 - 1  and a second set of links for supporting needles  42  in portion  30 - 2 . Links  52 L and  66 L may be joined by respective couplers  82  (e.g., removable pins, screws, magnets, springs, or other configurable coupling structures). During system configuration, a user of system  30  may select a desired size (number of needles, number of guide bars, etc.) for system  30  and may use couplers  82  to create corresponding linked chains from links  52 L and  66 L. For example, guide bar support structure  52  may be formed by coupling a desired number of links  52 L together using couplers  82  and first and second needle bed chains may be formed by coupling desired numbers of links  66 L together using couplers  82 . 
     The shape of knitted fabric tubes that are produced by system  30  may be adjusted to exhibit bends along their length and to produce sidewalls with desired cross-sectional profiles.  FIG.  19    is a cross-sectional side view of an illustrative fabric tube with a longitudinal bend. As shown in  FIG.  19   , fabric  14  has the shape of a hollow tube having a hollow cylindrical interior  90  surrounded by a wall of fabric of thickness T. System  30  can be used to adjust the value of thickness T (e.g., by adjusting gap G, as described in connection with  FIG.  14   ). System  30  can also be used to adjust the diameter TD of the tube (e.g., the diameter of hollow interior  90 ). In the example of  FIG.  19   , the tube of fabric  14  has a longitudinal bend (a bend along its length that causes a bend in its longitudinal axis  102 ) with a longitudinal bend angle BA. The value of angle BA may be 0-90°, a non-zero angle of less than 10°, less than 40°, less than 120°, less than 180°, at least 5°, at least 45°, at least 80°, at least 160°, or other suitable bend angle value. To accommodate bend angle BA of the bend in the fabric tube, the outer portion of the fabric tube at the bend (see, e.g., portion  94  of  FIG.  19   ) may be provided with extra rows of loops relative to the inner portion of the fabric tube (see, e.g., portion  96 ). The inclusion of extra rows and/or selective removal of rows can be used to produce a tube with a desired centerline radius (e.g., a desired value of centerline radius CLR measured from point  94  to longitudinal axis  102  of the tube). 
     Stitch tightness (the size of stiches and therefore the density of stiches per length along a row of stiches) can also be adjusted selectively using system  30  along various portions of the walls of a fabric tube. For example, stitch tightness in a portion of a row of stiches can be loosened (reduced) in an outer layer of fabric  14  and stitch tightness can be tightened (increased) in a corresponding inner layer of fabric  14  when the fabric is being bent around the corner of a square tube (e.g., to accommodate corners such as the four right-angle corners  104  of the fabric tube shown in the cross-sectional profile of  FIG.  20   ).  FIGS.  21  and  22    show additional illustrative cross-sectional profiles that may be produced during knitting of the fabric tube by system  30 . In general, any suitable cross-sectional tube profile may be produced during knitting. The configurations of  FIGS.  20 ,  21 , and  22    are illustrative. 
     The use of selective adjustments to stitch tightness in fabric  14  to produce tubes of fabric  14  with desired cross-sectional profiles is illustrated further in  FIGS.  23 ,  24 ,  25 , and  26   . As shown in these diagrams, layers of fabric  14  (e.g., inner and/or outer layers) may be provided higher stitch tightness portions HLD, lower stitch tightness portions LLD, and/or intermediate stitch tightness portions ILD having stitch tightness values that lie between the high tightness values of portions HLD and the low tightness values of portions LLD. Portions HLD, LLD, and ILD may be distributed around the periphery of the fabric tube as needed to accommodate bends at corners and other curved and/or straight portions of the sidewalls of the tube of fabric. In this way, desired cross-sectional profiles with bends may be produced for the walls of fabric tubes produced by system  30 . 
     In the example of  FIG.  23   , inner fabric layer  14 - 1  of fabric  14  may have a higher stitch tightness (portion HLD) than outer fabric layer  14 - 2  (portion LLD) because inner fabric layer  14 - 1  has a smaller diameter than outer fabric layer  14 - 2 . In the example of  FIG.  24   , the inner and outer fabric layers of planar sidewall portions of the tube have intermediate tightness portions ILD, because these layers run parallel to each other. At corners  104 , inner layer  14 - 1  may have high tightness portion HLD and opposing outer layer  14 - 2  may have low tightness portion LLD. Similarly, varying stitch tightness values may be used along the rows of stiches (strand loops) in fabric  14  of  FIGS.  25  and  26    to accommodate lateral bends (bends perpendicular to longitudinal tube axis  102 ) in fabric  14 . 
     As shown in  FIG.  27   , a tube of fabric may be bent sufficiently along its longitudinal axis to form a C-shaped section of tubing (e.g., with sidewalls partially removed). This type of tubing may be used to form an enclosure (e.g., a case for headphones), a bag, a pair of head-mounted googles, and/or other suitable device structures (see, e.g., fabric  14  on housing  12  of item  10  of  FIG.  1   ). A spiral tube may also be formed by creating localized variations in stitch tightness around the periphery of the tube and along the length of the tube, as shown in the cross-sectional tube profile of  FIG.  28    and the perspective view of a corresponding tube with spiral structures of  FIG.  29   . 
     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: 20180406
Publication Date: 20221220
Grant Date: 20221220
Priority Date: 20171002
Inventors: PODHAJNY, DANIEL A.
HAMADA, Yohji
Assignee: APPLE INC
CPC Classifications: [{"code": "D10B2403/021", "inventive": false, "first": false, "tree": "[]"}, {"code": "D10B2401/18", "inventive": false, "first": false, "tree": "[]"}, {"code": "D04B37/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "D04B21/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "D04B23/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "D04B35/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "D04B21/202", "inventive": true, "first": false, "tree": "[]"}, {"code": "D04B21/205", "inventive": false, "first": false, "tree": "[]"}, {"code": "D04B1/225", "inventive": false, "first": false, "tree": "[]"}, {"code": "D04B27/08", "inventive": true, "first": true, "tree": "[]"}, {"code": "D04B21/205", "inventive": false, "first": false, "tree": "[]"}, {"code": "D04B37/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "D04B21/202", "inventive": true, "first": false, "tree": "[]"}, {"code": "D04B21/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "D04B1/225", "inventive": false, "first": false, "tree": "[]"}, {"code": "D04B35/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "D04B27/08", "inventive": true, "first": true, "tree": "[]"}, {"code": "D04B23/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "D04B27/26", "inventive": true, "first": false, "tree": "[]"}, {"code": "D04B27/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "D04B25/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "D04B21/20", "inventive": true, "first": true, "tree": "[]"}, {"code": "D10B2403/0333", "inventive": false, "first": false, "tree": "[]"}, {"code": "D04B25/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "D04B27/06", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 84492595