PATENT DOCUMENT

Publication Number: US-10829878-B2
Application Number: US-201815913653-A
Country: US
Kind Code: B2

Title: Warp knit fabrics with variable path weft strands

Abstract:
An item may include fabric or other materials formed from intertwined strands of material. The strands of material may include non-conductive strands and conductive strands. The strands may be intertwined by a warp knitting machine to produce a warp knit fabric. The warp knit fabric may include intertwined warp strands and weft insertion strands that are inserted amongst the warp strands. The weft insertion strands may extend across less than all of the warp strands. The weft insertion strands may include parallel segments that each extend across a different portion of the warp strands. The segments of weft insertion strands may have different widths relative to one another and relative to the width of the fabric. The weft insertion strands may be inserted into the warp knitting machine across the warp strands using a weft insertion device that is positioned by a computer-controlled positioner.

Claims:
What is claimed is: 
     
       1. A warp knit fabric, comprising:
 a plurality of warp strands intertwined with one another, wherein the warp strands include a first warp strand that forms a first edge of the fabric and a second warp strand that forms a second edge of the fabric and wherein a width of the warp knit fabric extends from the first edge to the second edge; and 
 a weft strand inserted across the warp strands between the first and second edges of the fabric, wherein the weft strand extends across less than all of the warp strands, wherein the weft strand is interposed between first and second consecutive rows of stitches in the warp knit fabric, and wherein the weft strand comprises a conductive strand that conveys electrical signals. 
 
     
     
       2. The warp knit fabric defined in  claim 1  wherein the weft strand has a plurality of parallel weft strand segments and wherein each weft strand segment extends across at least some of the warp strands. 
     
     
       3. The warp knit fabric defined in  claim 2  wherein the weft strand segments include at least first weft strand segment that extends across a first set of warp strands in the plurality of warp strands and a second weft strand segment that extends across a second set of warp strands in the plurality of warp strands that is different than the first set of warp strands. 
     
     
       4. The warp knit fabric defined in  claim 2  wherein a spacing between the weft strand segments is uniform. 
     
     
       5. The warp knit fabric defined in  claim 2  wherein a spacing between the weft strand segments of the weft strand is non-uniform. 
     
     
       6. The warp knit fabric defined in  claim 1  further comprising:
 an additional weft strand inserted across the warp strands between the first and second edges of the fabric, wherein the additional weft strand extends across less than all of the warp strands. 
 
     
     
       7. The warp knit fabric defined in  claim 6  wherein the weft strand follows a first pattern in the warp knit fabric, wherein the additional weft strand follows a second pattern in the warp knit fabric, and wherein the first pattern is different than the second pattern. 
     
     
       8. The warp knit fabric defined in  claim 6  wherein the weft strand extends across a first set of warp strands in the plurality of warp strands, wherein the additional weft strand extends across a second set of warp strands in the plurality of warp strands, and wherein the first set of warp strands is different than the second set of warp strands. 
     
     
       9. A warp knit textile, comprising:
 a first layer comprising a first plurality of warp strands and a weft insertion strand that extends across less than all of the warp strands in the first plurality of warp strands, wherein the weft insertion strand is interposed between first and second consecutive rows of stitches in the first layer; 
 a second layer comprising a second plurality of warp strands; and 
 a spacer layer interposed between the first and second layers and comprising a third plurality of warp strands that couple the first layer to the second layer. 
 
     
     
       10. The warp knit textile defined in  claim 9  wherein the second layer comprises an additional weft insertion strand that extends across less than all of the warp strands in the second plurality of warp strands. 
     
     
       11. The warp knit textile defined in  claim 10  wherein the weft insertion strand and the additional weft insertion strand comprise conductive strands. 
     
     
       12. The warp knit textile defined in  claim 11  wherein the third plurality of warp strands comprise insulating strands. 
     
     
       13. The warp knit textile defined in  claim 12  wherein the insertion strand in the first layer overlaps the additional weft insertion strand in the second layer.

Description:
This application claims priority to U.S. patent application Ser. No. 15/738,096, filed Dec. 19, 2017, which is a 35 U.S.C. 371 national stage application of international application No. PCT/US2016/038678, filed Jun. 22, 2016, which claims the benefit of provisional patent application No. 62/186,285, filed Jun. 29, 2015, all of which are hereby incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     This relates generally to items formed from strands of material and, more particularly, to items formed from intertwined conductive and non-conductive strands of material. 
     It may be desirable to form items such a bags, clothing, and other items from intertwined strands of material. For example, woven or knitted fabric or braided strands may be used in forming portions of an item. 
     In some situations, it may be desirable to form items using warp knit fabric. Warp knit fabrics allow for a variety of fabric constructions and can be knitted into three-dimensional structures with multiple layers. 
     Warp knit fabrics sometimes include inserted weft and/or warp threads. The inserted weft and warp threads lie flat in the knitted fabric and can provide strength and rigidity to the fabric. 
     In conventional warp knitting machines, weft threads are inserted using a weft thread carrier that holds each weft thread across the entire width of the knitting machine. Weft threads that are inserted in the fabric with this type of equipment have a fixed path, typically spanning the entire width of the fabric. 
     Having weft threads restricted to one width and one pattern in a warp knit fabric can place undesirable limitations on the layout and design of the warp knit fabric. These limitations are especially cumbersome when forming fabrics with conductive signal paths and conductive regions. For example, fixed-pattern weft threads in a warp knit fabric cannot be used to form conductive regions of different shapes, sizes, and patterns in the fabric. 
     It would therefore be desirable to be able to form improved fabric constructions for warp knit fabrics. 
     SUMMARY 
     An item may include fabric or other materials formed from intertwined strands of material. The strands of material may include non-conductive strands and conductive strands. The strands may be intertwined by a warp knitting machine to produce a warp knit fabric. The warp knit fabric may include intertwined warp strands and weft insertion strands that are inserted amongst the warp strands. 
     The weft insertion strands may extend across less than all of the warp strands in the warp knit fabric. The weft insertion strands may include parallel segments in the fabric that each extend across a different portion of the warp strands. The segments of weft insertion strands may have different widths relative to one another and relative to the width of the fabric. For example, some weft insertion strands may extend across the entire width of the fabric whereas other weft insertion strands may extend across only a portion of the width of the fabric. 
     To form a warp knit fabric having weft insertion strands of variable width, weft insertion strands may be inserted into a warp knitting machine using a weft insertion device that is positioned by a computer-controlled positioner. The computer-controlled positioner may move the weft insertion device across a desired width of the fabric corresponding to the desired width of the weft strand in the fabric. The weft insertion device may feed a weft strand into the warp knitting machine as the weft insertion device moves the desired distance across the warp knitting machine. If desired, multiple weft insertion devices may be used in parallel to insert multiple weft strands into the fabric during knitting. The weft insertion devices may be independently controlled and, if desired, may produce different weft strand patterns in the fabric. 
     In other arrangements, the weft insertion strands may be preloaded onto a conveyor surface in a pattern corresponding to the pattern to be created in the warp knit fabric. For example, the weft insertion strands may be wrapped around a series of posts on the conveyor surface to create parallel segments having different widths. They conveyor may feed each segment into the warp knitting machine to thereby embed weft insertion strands of variable widths in the warp knit fabric. 
     The warp knitting machine may be a tricot knitting machine, a single needle bar Raschel knitting machine, a double needle bar knitting machine, or other suitable knitting machine. In a double needle bar Raschel knitting machine, a multi-layer fabric may be produced. For example, a warp knit textile having first and second layers and a spacer layer joining the first and second layers may be produced. If desired, any one or more of the layers in a multi-layer warp knit textile may include weft insertion fibers having variable paths. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative item that may include strands of material in accordance with an embodiment. 
         FIG. 2  is a top view of a portion of a warp knit fabric that may include conductive strands in accordance with an embodiment. 
         FIG. 3  is a top view of a portion of a warp knit fabric having weft insertion strands with different widths in accordance with an embodiment. 
         FIG. 4  is a diagram of illustrative equipment for forming warp knit fabrics having weft insertion strands with different patterns in accordance with an embodiment. 
         FIG. 5  is a perspective view of illustrative warp knitting equipment that may be used to form warp knit fabrics in accordance with an embodiment. 
         FIG. 6  is a side view of illustrative warp knitting equipment in a first position during loop formation in accordance with an embodiment. 
         FIG. 7  is a side view of illustrative warp knitting equipment in a second position during loop formation in accordance with an embodiment. 
         FIG. 8  is a side view of illustrative warp knitting equipment in a third position during loop formation in accordance with an embodiment. 
         FIG. 9  is a cross-sectional side view of an illustrative warp knit fabric showing how weft insertion strands may be inserted during knitting in accordance with an embodiment. 
         FIG. 10  is a perspective view of illustrative equipment including a weft insertion device on which weft insertion strands with variable widths are placed in a predetermined pattern in accordance with an embodiment. 
         FIG. 11  is a perspective view of illustrative knitting equipment for knitting a multi-layer fabric including a weft insertion device that is positioned by a computer-controlled positioner in accordance with an embodiment. 
         FIG. 12  is a perspective view of illustrative knitting equipment for knitting a fabric including multiple weft insertion devices that are positioned by computer-controlled positioners in accordance with an embodiment. 
         FIG. 13  is a top view of an illustrative warp knit fabric having a weft insertion strand with parallel segments of variable width in accordance with an embodiment. 
         FIG. 14  is a top view of an illustrative warp knit fabric having a weft insertion strand with parallel segments of variable width and different patterns in accordance with an embodiment. 
         FIG. 15  is a top view of an illustrative warp knit fabric having a weft insertion strand with parallel segments of variable width and variable spacing in accordance with an embodiment. 
         FIG. 16  is a top view of an illustrative warp knit fabric having weft insertion strands and warp insertion strands with variable spacing to produce regions with different resolutions in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Strands of material may be incorporated into strand-based items such as strand-based item  10  of  FIG. 1 . Item  10  may be an electronic device or an accessory for an electronic device such as 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 wrist-watch 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, etc.), or may be any other suitable strand-based item. 
     Strands in strand-based item  10  may form all or part of a housing wall for an electronic device, may form internal structures in an electronic device, or may form other strand-based structures. Strand-based 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. 
     Item  10  may include intertwined strands  12 . The strands may be intertwined using strand intertwining equipment such as weaving equipment, knitting equipment, braiding equipment, or equipment that intertwines strands by entangling the strands with each other in other ways (e.g., to form felt). Intertwined strands  12  may, for example, form woven or knitted fabric or other fabric (i.e., item  10  may be a fabric-based item), a braided cord, etc. 
     Strands  12  may be single-filament strands or may be threads, yarns, or other strands that have been formed by intertwining multiple filaments of material together. Strands  12  may be formed from polymer, metal, glass, graphite, ceramic, natural fibers such as cotton, bamboo, wool, or other organic and/or inorganic materials and combinations of these materials. Strands  12  may be insulating or conductive. 
     Conductive coatings such as metal coatings may be formed on non-conductive strands (e.g., plastic cores) to make them conductive and strands such as these may be coated with insulation or left bare. Reflective coatings such as metal coatings may be applied to strands  12  to make them reflective. Strands  12  may also be formed from single-filament metal wire, multifilament wire, or combinations of different materials. 
     Strands  12  may be conductive along their entire length or may have conductive segments (e.g., metal portions that are exposed by locally removing insulation or that are formed by adding a conductive layer to a portion of a non-conductive strand.). Threads and other multifilament yarns that have been formed from intertwined filaments may contain mixtures of conductive fibers and insulating fibers (e.g., metal strands or metal coated strands with or without exterior insulating layers may be used in combination with solid plastic fibers or natural fibers that are insulating). 
     Item  10  may include additional mechanical structures  14  such as polymer binder to hold strands  12  together, support structures such as frame members, housing structures (e.g., an electronic device housing), and other mechanical structures. 
     Circuitry  16  may be included in item  10 . Circuitry  16  may include components that are coupled to strands  12 , components that are housed within an enclosure formed by strands  12 , components that are attached to strands  12  using welds, solder joints, adhesive bonds (e.g., conductive adhesive bonds), crimped connections, or other electrical and/or mechanical bonds. Circuitry  16  may include metal structures for carrying current, integrated circuits, discrete electrical components such as resistors, capacitors, and inductors, switches, connectors, light-emitting components such as light-emitting diodes, audio components such as microphones and speakers, vibrators, solenoids, piezoelectric devices, and other electromechanical devices, connectors, microelectromechanical systems (MEMs) devices, pressure sensors, light detectors, proximity sensors, force sensors, moisture sensors, temperature sensors, accelerometers, gyroscopes, compasses, magnetic sensors, touch sensors, and other sensors, components that form displays, touch sensors arrays (e.g., arrays of capacitive touch sensor electrodes to form a touch sensor that detects touch events in two dimensions), and other input-output devices. Circuitry  16  may also include control circuitry such as non-volatile and volatile memory, microprocessors, application-specific integrated circuits, system-on-chip devices, baseband processors, wired and wireless communications circuitry, and other integrated circuits. 
     Item  10  may interact with electronic equipment or other additional items  18 . Items  18  may be attached to item  10  or item  10  and item  18  may be separate items that are configured to operate with each other (e.g., when one item is a case and the other is a device that fits within the case, etc.). Circuitry  16  may include antennas and other structures for supporting wireless communications with item  18 . Item  18  may also interact with strand-based item  10  using a wired communications link or other connection that allows information to be exchanged. 
     In some situations, item  18  may be an electronic device such as a cellular telephone, computer, or other portable electronic device and strand-based item  10  may form a case or other structure that receives the electronic device in a pocket, an interior cavity, or other portion of item  10 . In other situations, item  18  may be a wrist-watch device or other electronic device and item  10  may be a strap or other strand-based item that is attached to item  18 . In still other situations, item  10  may be an electronic device, strands  12  may be used in forming the electronic device, and additional items  18  may include accessories or other devices that interact with item  10 . 
     If desired, magnets and other structures in items  10  and/or  18  may allow items  10  and  18  to interact wirelessly. One item may, for example, include a magnet that produces a magnetic field and the other item may include a magnetic switch or magnetic sensor that responds in the presence of the magnetic field. Items  10  and  18  may also interact with themselves or each other using pressure-sensitive switches, pressure sensors, force sensors, proximity sensors, light-based sensors, interlocking electrical connectors, etc. 
     The strands that make up item  10  may be intertwined using any suitable strand intertwining equipment. For example, strands  12  may be woven together to form a fabric. The fabric may have a plain weave, a satin weave, a twill weave, or variations of these weaves, may be a three-dimensional woven fabric, or may be other suitable woven fabric. If desired, the strands that make up item  10  may be intertwined using knitting equipment, braiding equipment, or other strand intertwining equipment. Item  10  may also incorporate more than one type of fabric or intertwined strand-based material (e.g., item  10  may include both woven and knitted portions). 
     The strands that make up item  10  may be intertwined to form a fabric such as illustrative fabric  20  of  FIG. 2 . Fabric  20  may include strands  12 . Strands  12  may be formed from conductive and/or insulating materials. As an example, fabric may be formed from insulating strands interspersed with conductive strands. In the illustrative configuration of  FIG. 2 , fabric  20  is a warp knit fabric having columns of warp strands  12 - 1  that zigzag along the length L of fabric  20 . Each warp strand  12 - 1  has a number of loops, with each loop securing a loop of an adjacent strand from a previous row. For example, the loops of row  22 B in fabric  20  secure the loops of row  22 A in fabric  20 . 
     If desired, additional strands may be inserted into a warp knit fabric. For example, as shown in  FIG. 3 , fabric  20  may include weft strands  12 - 2  and warp strands  12 - 3  that are inserted into the intertwined warp strands  12 - 1 . Weft strands  12 - 2  that are inserted across the width W of fabric  20  may sometimes be referred to as weft insertion strands. Warp strands  12 - 3  that are inserted along the length L of fabric  20  may sometimes be referred to as warp insertion strands. 
     In contrast to woven fabrics in which weft threads have a wave-like shape due to the over-under weaving pattern, weft insertion strands  12 - 2  are able to lie flat in fabric  20  because the strands are inserted into fabric  20  between rows of stitching. For example, as shown in  FIG. 3 , weft insertion strand  12 - 2  is inserted into fabric  20  between row A of stitches and row B of stiches. 
     Weft insertion strands  12 - 2  and warp insertion strands  12 - 3  may be formed from the same material as warp strands  12 - 1  or may be formed from a different material. For example, warp strands  12 - 1  may be insulating strands while weft insertion strands  12 - 2  and/or warp insertion strands  12 - 3  may be conductive strands. If desired, warp strands  12 - 1  may be conductive strands while weft insertion strands  12 - 2  and/or warp insertion strands  12 - 3  may be insulating strands. 
     The distance spanned by a weft insertion strand across a fabric may be referred to herein as the “width” of the weft insertion strand. Because a single weft strand may form multiple rows in a fabric, the width of a weft insertion strand may sometimes refer to the width of a given row formed by a segment of a weft insertion strand. For example, weft strand  12 - 2 ′ and weft-strand  12 - 2 ″ may be formed from two separate weft strands or may be formed from a single weft strand that extends back and forth across the fabric. In other words, a single weft strand may have multiple widths, with each width corresponding to a respective row formed by a segment of the weft strand. 
     To accommodate different fabric patterns and designs, fabric  20  may include weft insertion strands  12 - 2  that follow a variable pattern in fabric  20 . For example, weft insertion strands  12 - 2  may span various distances across the width of fabric  20 . Some weft insertion strands  12 - 2  span the width W of fabric  20  (e.g., extending across all of warp fibers  12 - 1 ), while other weft insertion strands such as strand  12 - 2 ′ and  12 - 2 ″ do not span the entire width W of fabric  20  (e.g., extending across less than all of warp fibers  12 - 1 ). In the illustrative example of  FIG. 3 , strand  12 - 2 ′ has a width W 1  that is less than width W of fabric  20  and strand  12 - 2 ″ has a width W 2  that is less than width W of fabric  20  and width W 1  of strand  12 - 1 . Varying the width of weft insertion strands  12 - 2  may allow patterns that would otherwise not be possible in a warp knit fabric. 
     Illustrative equipment and operations of the type that may be involved in forming fabric-based items that include weft insertion strands of variable patterns are shown in  FIG. 4 . 
     As shown in  FIG. 4 , the equipment of  FIG. 4  may be provided with strands from strand source  24 . The strands provided by strand source  24  may be single-strand filaments or may be threads, yarns, fibers, or other strands that have been formed by intertwining single-strand filaments. Strands 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 strand cores. Strands may also be formed from single filament metal wire or stranded wire. Strands may be insulating or conductive. Strands may be conductive along their entire length or may have conductive segments (e.g., metal portions that are exposed by locally removing polymer insulation from an insulated conductive fiber). Threads and other multi-strand bundles that have been formed from intertwined filaments may contain mixtures of conductive strands and insulating strands (e.g., metal strands or metal coated strands with or without exterior insulating layers may be used in combination with solid plastic strands or natural strands that are insulating). 
     Strand source  24  may provide warp strands (e.g., warp strands  12 - 1  of  FIG. 3 ) to intertwining equipment  28  and weft strands (e.g., weft insertion strands  12 - 2  of  FIG. 3 ) to weft strand insertion equipment  26 . Weft strand insertion equipment  26  may feed weft strands  12 - 2  into intertwining equipment  28 . 
     Warp strands  12 - 1  ( FIG. 3 ) from strand source  24  and weft strands  12 - 2  from weft strand insertion equipment  26  may be intertwined using intertwining equipment  28  to produce fabric  20 . Equipment  28  may include knitting equipment such as tricot knitting equipment, Raschel knitting equipment (e.g., single needle bar or double needle bar Raschel knitting equipment), Milanese knitting equipment, or other suitable equipment for intertwining strands from strand source  24 . Equipment  28  may be automated. For example, equipment  28  may include computer-controlled actuators that manipulate and intertwine fibers from source  24 . Intertwining equipment  28  may be configured to produce three-dimensional fabric structures (e.g., fabrics with potentially complex multi-layer structures). For example, intertwining equipment  28  may include knitting equipment that produces three-dimensional structures, a three-dimensional weaving machine, tools for producing three-dimensional braided fabrics, etc. 
     Weft strand insertion equipment  26  may include one or more feeders that feed weft strands  12 - 2  into warp knitting machine  28  during knitting. If desired, weft strand insertion equipment  26  may be automated. For example, equipment  26  may include computer-controlled actuators that control when weft strands  12 - 2  are inserted into knitting machine  28  and that controls the width spanned by each weft strand  12 - 2  in fabric  20 . The widths spanned by weft strands  12 - 2  may be predetermined prior to knitting or may be determined and adjusted during the knitting process. Weft strand insertion equipment  26  may produce rows of weft strands  12 - 2  with variable widths in fabric  20 . 
     As shown in  FIG. 4 , fabric  20  that includes inserted weft strands  12 - 2  may be processed using additional tools and assembly equipment  32 . Equipment  32  may be used in processing strands  12 . Equipment  32  may be used in forming electrical connections between strands  12  and attaching electronic components such as electronic components in circuitry  16  of  FIG. 1  to strands such as conductive strands  12 . For example, equipment  32  may be used to attach electrical components to strands  12  using solder joints, crimped metal connections, welds, conductive adhesive, or other conductive attachment structures. The electrical components that are attached to strands in this way may include light-emitting components, integrated circuits, light-emitting diodes, light-emitting diodes that are packaged with transistor-based circuitry such as communications circuitry and/or light-emitting diode driver circuitry that allows each component to operate as a pixel in a display, discrete components such as resistors, capacitors, and inductors, audio components such as microphones and/or speakers, sensors such as touch sensors (with or without co-located touch sensor processing circuitry), accelerometers, temperature sensors, force sensors, microelectromechanical systems (MEMS) devices, transducers, solenoids, electromagnets, pressure sensors, light-sensors, proximity sensors, buttons, switches, two-terminal devices, three-terminal devices, devices with four or more contacts, etc. Electrical connections for attaching electrical components to strands  12  using equipment  32  may be formed using solder, conductive adhesive, welds, molded package parts, mechanical fasteners, wrapped strand connections, press-fit connections, crimped connections (e.g., bend metal prong connections), and other mechanical connections, portions of liquid coatings (e.g., metallic paint, conductive adhesive, etc.) that are selectively applied to strands  12  using equipment  32 , or using any other suitable arrangement for forming an electrical short between conductive structures. 
     Equipment  32  may be used to attach fabric  20  to housing structures formed from plastic, metal, glass, or other materials. Fabric  20  may be sewn, cut, and otherwise incorporated into fabric-based items to form a finished fabric-based item (e.g., electronic device  10 ). 
       FIG. 5  is a perspective view of illustrative knitting equipment that may be used to knit fabric  20 . As shown in  FIG. 5 , knitting equipment  20  may include guide bar  34  having a number of guides  36 . Each warp thread  12 - 1  may be threaded through a respective one of guides  36 . Needle bar  40  may include a number of needles  38 . All of the needles  38  in needle bar  40  may move in unison. Needles  38  may be bearded needles having beards  38 B or may be any other suitable type of knitting needle (e.g., latch needle, compound needle, carbine needle, etc.). 
     Loops are made between adjacent warp strands  12 - 1  by moving various components of knitting machine  28 . Guide bar  34  is configured to move back and forth between needles  38  along direction  42 . This movement is sometimes referred to as a swing. Guide bar  34  is also configured to move laterally in direction  44 , either in front of or behind needles  38 . This movement is sometimes referred to as a shog.  FIGS. 6, 7, and 8  show how loops are formed in a warp knit fabric using knitting equipment of the type shown in  FIG. 5 . 
     As shown in  FIG. 6 , loop formation begins with guide  36  swinging in direction  66  from the front of machine  28  (e.g., opposite the open side of needles  38 ) to the back of machine  28  (e.g., on the open side of needles  38 ) to bring warp thread  12 - 1  between adjacent needles  38  to the back of machine  28 . At this stage, closing structure  46  is down such that beard  38 B of needle  38  is open. 
     In  FIG. 7 , guide  36  is shogged laterally behind needle  38  in direction  50  to overlap warp strand  12 - 1  behind needle  38 . Following this lateral shog, guide  36  swings from back to front in direction  52 , bringing warp thread  12 - 1  back between needles  38  (e.g., on the opposite side of needle  38  as the front-to-back swing of  FIG. 6 ). 
     In  FIG. 8 , closing structure  46  has moved upwards in direction  62  to trap newly made loop  56  (e.g., the loop around needle  38  formed from the overlap step of  FIG. 7 ) in needle  38 . Closed needle  38  then moves downward in direction  58  to pull new loop  56  in direction  60  through a previously made loop such as old loop  54 , which is wrapped around a lower portion of needle  38 . After new loop  56  has been pulled through old loop  54 , sinkers such as sinker  48  may be moved backwards in direction  64  to release old loop  54  (a process sometimes referred to as knock-over). After disengaging the old loops from needle  38 , sinker  46  may move forward in direction  68  to secure fabric  20  prior to needles  38  rising for the next cycle of loop formation. 
     The knitting equipment of  FIGS. 5, 6, 7, and 8  is merely illustrative. Similar movements may apply with various types of knitting machines (e.g., tricot machines, Raschel machines, machines with compound needles, bearded needles, or other suitable type of needle, etc.). 
       FIG. 9  is a cross-sectional side view of a warp knit fabric  20  having inserted weft strands. As shown in  FIG. 9 , weft insertion strands  12 - 2  may be inserted into fabric  20  between previously formed loops  54  of fabric  20  prior to pulling a new loop (e.g., a new loop such as loop  56  of  FIG. 8 ) through previously formed loop  54 . Once the new loops are pulled through the old loops, warp insertion strands  12 - 2  may be integrated into fabric  20 . 
       FIG. 10  is a perspective view of illustrative equipment that may be used to insert weft strands  12 - 2  into fabric  20  during knitting. As shown in  FIG. 10 , weft strand insertion equipment  26  may include a conveyor belt structure such as conveyor  74  having a number of structures  70  (e.g., hooks, pins, posts, etc.) around which weft strands  12 - 2  are wrapped. Hooks  70  hold each weft strand segment  12 S parallel to the width W of fabric  20 . To insert weft strand segments  12 S into fabric  20 , rollers  80  rotate in direction  72  which in turn moves conveyor surface  76  in direction  78 . Weft segments  12 S are released from conveyor  74  and placed cross-wise into fabric  20  (see, e.g.,  FIG. 9 ). 
     A shown in  FIG. 10 , the width of weft strand segments  12 S is determined by the spacing between posts  70 . If desired, equipment  26  may have a uniform spacing between posts  70  to form weft segments of uniform width, or equipment  26  may have variable spacing between posts  70  to form weft segments with variable width, as shown in  FIG. 10 . For example, a distance D 1  may separate one pair of opposing posts  70 , while a distance D 2  (e.g., a distance less than D 1 ) may separate another pair of opposing posts. 
     If desired, the positions of posts  70  on conveyor surface  76  may be fixed or the positions may be adjustable. In either case, the weft insertion strand  12 - 2  may be pre-loaded onto conveyor surface  76  in a particular pattern. The pattern in which weft strand  12 - 2  is placed on conveyor surface  76  may correspond to the pattern to be created in fabric  20  with weft strand  12 - 2 . For example, the distances D 1  and D 2  between neighboring pairs of posts  70  on conveyor surface  76  may create first and second weft insertion segments  12 S in fabric  20  having widths D 1  and D 2 . 
     The example of  FIG. 10  in which weft insertion equipment  26  includes a conveyor system on which the pattern of weft insertion strands  12 - 2  is pre-loaded prior to inserting the weft strands  12 - 2  in fabric  20  is merely illustrative. If desired, weft insertion equipment  26  may include computer-controlled weft strand positioning equipment that precisely moves and positions weft strands in fabric  20 . This type of arrangement is shown in  FIG. 11 . 
     In the illustrative example of  FIG. 11 , fabric  20  is a multi-layer fabric having a spacer layer  82 S interposed between first and second outer layers  82 A and  82 B. Multi-layer fabrics of this type may, for example, be formed using Raschel double-needle bar machine in which threaded guide bars form outer layers  82 A and  82 B and an additional threaded guide bar is used to attach outer layer  82 A and  82 B with spacer layer  82 S. 
     In some embodiments, the spacer construction of  FIG. 11  may be used to form a touch-sensitive textile. Each outer layer  82 A and  82 B may include a set of conductive strands. The spacer layer may compress or deform in response to a touch on the textile, which, in some cases, causes the distance between conductive strands in layer  82 A to come closer to the conductive strands in layer  82 B. The change in distance between the conductive strands may cause a change in capacitance between the conductive strands, which may be monitored by a sensing circuit. If desired, a force associated with the touch may be determined based on the change in capacitance. 
     As shown in  FIG. 11 , weft strand positioning equipment  26  may include a feeder  84  (sometimes referred to as a carrier, a weft insertion device, or weft strand positioner) that feeds weft strands  12 - 2  into fabric  20  during weaving. The location at which weft strands  12 - 2  are inserted into fabric  20  may be similar to that of  FIGS. 9 and 10  (e.g., between previously formed loops and newly wrapped strands to be looped with previously formed loops). In contrast to  FIG. 10  where the pattern of weft strands  12 - 2  is formed on equipment  26  prior to insertion, equipment  26  of  FIG. 11  produces the pattern of weft strands  12 - 2  as the weft strands are inserted into fabric  20 . For example, rather than feeding knitting machine  28  a stretched weft strand that is stretched between two hooks, feeder  84  may move across knitting machine  28  along direction  108  while feeding weft strand  12 - 2  into fabric  20  as knitting machine  28  knits fabric  20 . 
     Feeder  84  may be controlled by computer-controlled positioner  86 . If desired, computer-controlled positioner  86  may synchronize the movement and placement of feeder  84  with the operation of knitting machine  28  such that the pattern of weft insertion strands  12 - 2  can be customized and adjusted during knitting without requiring any change in operation of knitting machine  28 . 
     Computer-controlled positioner  86  manipulates feeder  84  to insert segments  12 S of weft strands  12 - 2  in fabric  20 . As shown in  FIG. 11 , weft segments  12 S may have different widths and may span different portions of fabric  20 . The width  110  of a given segment  12 S in fabric  20  may be determined by the movement of weft insertion equipment  26 . For example, to produce a segment of width  110  in fabric  20 , computer-controlled positioner  86  may move insertion device  84  across width  110  while placing weft segment  12 S into knitting machine  28 . The weft segment is integrated into fabric  20  as knitting machine  28  forms loops with warp strands  12 - 1 . 
     The example of  FIG. 11  in which weft strand positioning equipment  26  includes one feeder  84  is merely illustrative. If desired, weft strand positioning equipment  26  may include multiple feeders  84 . For example, one feeder  84  may feed weft strands  12 - 2  to layer  82 A while another feeder  84  feeds weft strands  12 - 2  to layer  82 B. If desired, weft strands  12 - 2  of layer  82 A and weft strands  12 - 2  of layer  82 B may be conductive and may overlap one another. The overlapping regions of conductive weft strands may, for example, form sensor electrodes as part of a touch sensor and/or force sensor in fabric  20 . 
     If desired, multiple feeders  84  may be used for any one or more of layers  82 A,  82 B, and  82 C. This type of arrangement is shown in  FIG. 12 . As shown in  FIG. 12 , weft insertion equipment  26  may include multiple feeders such as feeder  84 A controlled by positioner  86 A and feeder  84 B controlled by positioner  86 B. Feeders  84 A and  84 B may operate independently of one another to create multiple regions  90  of weft segments  12 S in fabric  20 . Because regions  90  of weft segments  12 S are created independently of one another, each region  90  may have a different pattern of weft segments. The widths of segments  12 S within a given region  90  may be fixed or may be variable. 
     The example of  FIG. 12  in which two feeders  84  are used to independently insert different weft strands  12 - 2  in fabric  20  is merely illustrative. If desired, one, two, three, four, or more than four feeders  84  may be used to insert and control the width of weft segments  12 S in fabric  20 . The ability to insert weft segments  12 S with variable widths and patterns allows for the creation of regions  90  having different shapes, sizes, and functions in fabric  20 . Regions  90  may create an aesthetically pleasing design in fabric  20  and/or may be used for functional purposes (e.g., to create different patterns, shapes, and sizes of touch-sensitive and/or force-sensitive regions in fabric  20 ). 
       FIGS. 13, 14, 15, and 16  show various patterns that can be made with a weft insertion strand using the equipment and methods described in  FIGS. 4-12 . 
     In the example of  FIG. 13 , weft strand  12 - 2  forms a number of parallel weft segments  12 S in fabric  20 . Weft segments  12 S may have different widths W. For example, weft segments  12 S in region  92  may have a greater width than weft segments  12 S in region  94 . In this example, the spacing S between adjacent segments  12 S is uniform in fabric  20 . However, if desired, segments  12 S may have a non-uniform spacing. 
     In the example of  FIG. 14 , weft strand  12 - 2  has segments of variable width and has different patterns in different regions of fabric  20 . In the example of  FIG. 15 , weft strand  12 - 2  has segments  12 S with variable width and a variable spacing S between neighboring segments. For example, one pair of segments  12 S may have be spaced apart by a distance  51 , whereas another pair of segments  12 S may be spaced apart by a distance S 2  that is less than  51 . 
     In the example of  FIG. 16 , fabric  20  includes both weft insertion strands  12 - 2  and warp insertion strands  12 - 3 . If desired, the spacing between weft strands  12 - 2  and the spacing between warp strands  12 - 3  may be adjusted to create regions of different resolutions. For example, as shown in  FIG. 16 , warp strands  12 - 3  in region  96  may be spaced closer together than warp strands  12 - 3  in other regions of fabric  20 . Weft strands  12 - 2  in region  98  may be spaced closer together than weft strands  12 - 2  in other regions of fabric  20 . This creates region  100  of closely spaced warp strands  12 - 3  and closely spaced weft strands  12 - 2 . In arrangements where warp strands  12 - 3  and weft strands  12 - 2  are conductive, region  100  may create a discrete touch-sensitive and/or force-sensitive region in fabric  20 . 
     In accordance with an embodiment, a warp knit fabric is provided that includes a plurality of warp strands intertwined with one another, the warp strands include a first warp strand that forms a first edge of the fabric and a second warp strand that forms a second edge of the fabric and a width of the warp knit fabric extends from the first edge to the second edge, and a weft strand inserted across the warp strands between the first and second edges of the fabric, the weft strand extends across less than all of the warp strands. 
     In accordance with another embodiment, the weft strand includes a conductive strand that conveys electrical signals. 
     In accordance with another embodiment, the weft strand has a plurality of parallel weft strand segments and each weft strand segment extends across at least some of the warp strands. 
     In accordance with another embodiment, the weft strand segments include at least first weft strand segment that extends across a first set of warp strands in the plurality of warp strands and a second weft strand segment that extends across a second set of warp strands in the plurality of warp strands that is different than the first set of warp strands. 
     In accordance with another embodiment, a spacing between the weft strand segments is uniform. 
     In accordance with another embodiment, a spacing between the weft strand segments of the weft strand is non-uniform. 
     In accordance with another embodiment, the warp knit fabric includes an additional weft strand inserted across the warp strands between the first and second edges of the fabric, the additional weft strand extends across less than all of the warp strands. 
     In accordance with another embodiment, the weft strand follows a first pattern in the warp knit fabric, the additional weft strand follows a second pattern in the warp knit fabric, and the first pattern is different than the second pattern. 
     In accordance with another embodiment, the weft strand extends across a first set of warp strands in the plurality of warp strands, the additional weft strand extends across a second set of warp strands in the plurality of warp strands, and the first set of warp strands is different than the second set of warp strands. 
     In accordance with an embodiment, a warp knit textile is provided that includes a first layer including a first plurality of warp strands and a first weft insertion strand that extends across less than all of the warp strands in the first plurality of warp strands, a second layer including a second plurality of warp strands, and a spacer layer interposed between the first and second layers and including a third plurality of warp strands that couple the first layer to the second layer. 
     In accordance with another embodiment, the second layer includes a second weft insertion strand that extends across less than all of the warp strands in the second plurality of warp strands. 
     In accordance with another embodiment, the first and second weft insertions strands include conductive strands. 
     In accordance with another embodiment, the third plurality of warp strands include insulating strands. 
     In accordance with another embodiment, the first weft insertion strand in the first layer overlaps the second weft insertion strand in the second layer. 
     In accordance with an embodiment, equipment for forming a warp knit textile is provided that includes a warp knitting machine that intertwines a plurality of warp strands, a weft insertion device that feeds weft insertion strands into the warp knitting machine across the warp strands, and a computer-controlled positioner that positions the weft insertion device relative to the warp knitting machine such that the weft insertion strands have different widths across the plurality of warp strands. 
     In accordance with another embodiment, the warp knitting machine includes a warp knitting machine selected from the group consisting of a tricot knitting machine, a single needle bar Raschel knitting machine, and a double needle bar Raschel knitting machine. 
     In accordance with another embodiment, the warp knitting machine has a width and the computer-controlled positioner moves the weft insertion device across less than all of the width of the warp knitting machine when the weft insertion device inserts a weft insertion strand. 
     In accordance with another embodiment, the warp knitting machine has a width, the computer-controlled positioner moves the weft insertion device across a first portion of the width of the warp knitting machine when the weft insertion device inserts a first weft insertion strand and across a second portion of the width of the warp knitting machine when the weft insertion device inserts a second weft insertion strand, and the first portion is different than the second portion. 
     In accordance with another embodiment, the equipment includes an additional weft insertion device that feeds additional weft insertion strands into the warp knitting machine across the warp strands, and an additional computer-controlled positioner that positions the additional weft insertion device relative to the warp knitting machine. 
     In accordance with another embodiment, the weft insertion device feeds the weft insertion strands into the warp knitting machine in a first pattern while the additional weft insertion device feeds the additional weft insertion strands into the warp knitting machine in a second pattern that is different than the first pattern. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20180306
Publication Date: 20201110
Grant Date: 20201110
Priority Date: 20150629
Inventors: HAMADA, Yohji
PODHAJNY, DANIEL A.
SUNSHINE, Daniel D.
CREWS, KATHRYN P.
WALKER, JOSEPH B.
Assignee: APPLE INC
CPC Classifications: [{"code": "D04B21/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "D04B23/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "D10B2403/021", "inventive": false, "first": false, "tree": "[]"}, {"code": "D04B21/14", "inventive": true, "first": true, "tree": "[]"}, {"code": "D10B2401/18", "inventive": false, "first": false, "tree": "[]"}, {"code": "D04B27/32", "inventive": true, "first": false, "tree": "[]"}, {"code": "D10B2401/16", "inventive": false, "first": false, "tree": "[]"}, {"code": "D04B21/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "D10B2401/18", "inventive": false, "first": false, "tree": "[]"}, {"code": "D10B2403/021", "inventive": false, "first": false, "tree": "[]"}, {"code": "D04B21/08", "inventive": true, "first": true, "tree": "[]"}, {"code": "D10B2401/16", "inventive": false, "first": false, "tree": "[]"}, {"code": "D04B23/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "D10B2403/02431", "inventive": false, "first": false, "tree": "[]"}, {"code": "D04B21/08", "inventive": true, "first": true, "tree": "[]"}, {"code": "D04B21/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "D04B23/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "D10B2401/16", "inventive": false, "first": false, "tree": "[]"}, {"code": "D10B2403/021", "inventive": false, "first": false, "tree": "[]"}, {"code": "D04B21/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "D10B2401/18", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 56409684