Three-dimensional shoe

Abstract

A knitted upper for an article of footwear. The knitted upper is formed essentially as a single piece in a three-dimensional knitting process. The knitted upper includes at least one activated shrink yarn.

Claims

1. A three-dimensionally knitted upper for an article of footwear comprising: at least one activated shrink yarn; a first region comprising a first number of knitted layers, wherein the first region is a bottom portion of the knitted upper, and wherein the bottom portion is configured to attach to a sole of the article of footwear; and a second region comprising a second number of knitted layers, wherein the second region is an upper portion of the knitted upper, wherein the second number of knitted layers is greater than the first number of knitted layers, and wherein the knitted upper is a single piece.

2. The knitted upper according to claim 1, wherein the at least one activated shrink yarn comprises at least one air-tack yarn.

3. The knitted upper according to claim 1, wherein the at least one activated shrink yarn is arranged in at least one of a heel portion of the knitted upper, a toe portion of the knitted upper, and the heel portion and the toe portion of the knitted upper.

4. The knitted upper according to claim 1, further comprising: at least one melted fuse yarn.

5. The knitted upper according to claim 1, wherein the knitted upper is essentially seamless.

6. The knitted upper according to claim 1, wherein the knitted upper further comprises: at least a first yarn; and at least a second yarn, wherein a number of plies of the second yarn is greater than a number of plies of the first yarn.

7. The knitted upper according to claim 1, wherein the first region comprises one knitted layer and the second region comprises two knitted layers.

8. A shoe, comprising: a knitted upper according to claim 1; and a sole.

9. A method of producing a knitted upper for an article of footwear, the method comprising: knitting at least one activatable shrink yarn into at least one of a heel region and a toe region of the knitted upper; knitting a first region of the knitted upper comprising a first number of knitted layers; knitting a second region of the knitted upper comprising a second number of knitted layers, wherein the second number of knitted layers is greater than the first number of knitted layers; knitting the knitted upper essentially as a single piece in a three-dimensional knitting process; arranging the knitted upper on a shoe last; and activating the at least one activatable shrink yarn such that the knitted upper shrinks to take the form of the shoe last.

10. The method according to claim 9, wherein activating the at least one activatable shrink yarn comprises heating the knitted upper by applying to the knitted upper saturated steam at a pressure between 1 bar and 5 bar for a time interval between 10 seconds and 20 seconds.

11. The method according to claim 9, wherein an area comprising the at least one activatable shrink yarn has an area shrinkage of at least 15% under application of saturated water steam at a pressure of 2 bar for 20 seconds.

12. The method according to claim 9, further comprising: knitting at least one fuse yarn into the knitted upper.

13. The method according to claim 9, wherein the knitted upper is knitted on a flatbed knitting machine comprising at least two needle beds.

14. The method according to claim 13, wherein during the knitting, there is a transfer of the yarns from a first needle bed to a second needle bed when changing a knitting stroke direction, wherein the transfer defines, on the knitted upper, a parting line, and wherein the parting line is arranged between a bottom region and a top region of the knitted upper.

15. The method according to claim 9, wherein the first region and the second region are knitted substantially simultaneously.

16. The method according to claim 13, wherein the knitted upper is knitted on the at least two needle beds to form a tubular knitted structure to create an essentially seamless knitted upper.

17. The method according to claim 9, wherein the shoe last is at least partially based on a customized model of an athlete's foot.

18. The knitted upper according to claim 1, wherein the knitted layers of the second region are connected.

19. The method according to claim 9, further comprising: connecting the knitted layers of the second region.

20. The knitted upper according to claim 1, wherein the second region further comprises a Jacquard knit portion.

Description

SHORT DESCRIPTION OF THE FIGURES

(1) In the following, the invention will be described in more detail with reference to the following figures. These figures show:

(2) FIGS. 1A, B: an exemplary upper according to the invention.

(3) FIGS. 2A, B: another exemplary upper according to the invention.

(4) FIGS. 3A, B: another exemplary upper according to the invention.

(5) FIGS. 4A, B: another exemplary upper according to the invention.

(6) FIGS. 5A-C: an exemplary upper and shoe according to the invention.

(7) FIGS. 6A-C: an exemplary method of consolidating of the upper according to the invention.

(8) FIGS. 7A, B: an exemplary illustration of a shrink yarn before (7A) and after activation (7B).

(9) FIG. 8: an exemplary illustration of the shrinkage effected by shrinking yarns in a knitted textile according to the invention.

(10) FIG. 9: an exemplary illustration of a shrink yarn.

(11) FIG. 10: a transfer between a first and a second needle bed.

(12) FIG. 11: an exemplary knitting pattern.

(13) FIG. 12: an exemplary upper according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(14) In the following only some possible embodiments of the invention are described in detail. The person skilled in the art is aware that these possible embodiments can be modified in a number of ways and combined with each other whenever compatible and that certain features may be omitted in so far as they appear dispensable.

(15) FIG. 1A shows an exemplary upper 11b according to the invention. The knitted upper 11b is for an article of footwear and is formed essentially as a single piece in a three-dimensional knitting process and comprises at least one activated shrink yarn. The upper 11b comprises a first region R1 comprising one knitted layer and a second region R2 comprising two knitted layers.

(16) In region R2, the two layers of yarn, or thread, are knitted together and at the same time, as a double layer jacquard. Thus, incorporating more than one layer does not substantially increase the knitting time required. The shown upper is in particular produced by using a flatbed knitting machine comprising two needle beds. The three-dimensional tubular structure comprising the double layer region R2 and the single layer region R1 is obtainable on the two needle beds of the flat knitting machine by alternating the use of the needles. Therefore, on the needle beds each layer is knitted only using a fraction of the needles, for instance knitting each region every second or third needle. This requires yarns, or threads, with sufficient elasticity to ensure a smooth knitted fabric. The amount of elasticity required is dependent on the machine gauge, i.e. the number of needles per inch. For example, with a machine gauge of 14, as suitable choice of yarn could be an air tack yarn comprising 40 to 80 denier elastane, also known as Lycra® or Spandex®, and 150 to 300 denier polyester with between 3 and 5 plies in each thread. Air tack yarn has the usual meaning in this context, that has already been provided above.

(17) However, other types of thread as well as other types of air tack yarn outside of the above range could still be used and possibly yield good results.

(18) Since the second number of knitted layers in region R2 is larger than the first number of knitted layers in region R1, the second region R2 is less elastic, stiffer, stronger and more stable than the first region R1. Of course, the weight per unit area of the second region R2 is generally larger than for region R1, though the exact factor depends also on the choice of yarns.

(19) The first region R1 is preferably located in a bottom region of the upper and/or a heel region of the upper and the second region R2 is preferably located in a top region of the upper.

(20) The bottom region of the upper 11b is attached to a sole when an article of footwear is formed from the upper 11b. Therefore, the primary element that provides structural stability in the bottom region of the upper 11b is the sole. Hence, it is not necessary for the upper 11b alone to provide structural support in a bottom region of the upper 11b. In order to provide the shoe with a lower weight, while still ensuring the comfort and the performances of an upper which is fully enclosing the foot of the wearer, it is therefore possible to provide the minimum number of layers in a bottom region of the upper 11b. For shoes, where additional support of the heel region is required, the sole element may extend upwards into a heel region, or alternatively a heel counter could be provided. Therefore, the same arguments that apply for the bottom portion of the upper 11b also apply to the heel region of the upper 11b and thus in order to provide a lightweight upper 11b, the minimum number of knitted layers in the heel region can be provided.

(21) In the embodiment illustrated in FIG. 1A, the heel region of the knitted upper 11b is reinforced by a knitted protrusion that is folded over the heel region doubling the layers of the knitted fabric on the heel region, as better specified later on.

(22) The top portion region of the upper 11b does not always benefit from additional structural elements that reinforce the structural stability of an article of footwear comprising an upper 11b according to the invention. This is in contrast to the bottom region of the upper which is generally provided with additional stability by the sole. Therefore, the structural stability of the top region of the upper 11b needs to be higher than the structural stability of the bottom region of the upper 11b. Therefore a larger number of layers could be provided in the top region of the upper 11b than in the bottom region of the upper 11b. Additional structural elements may however be provided on the top region of the upper, such as for instance lace supports that can be attached to the upper or directly to the sole.

(23) However, either of the regions R1 or R2 may be located anywhere on the upper 11b in order to engineer regions of stiffness or flexibility in any part of the upper 11b.

(24) The upper 11b is formed essentially as a single piece in a three-dimensional knitting process. In this way, the production process is simplified as a single production step can yield a tubular upper capable of enclosing the foot of a wearer and no additional operations, such as for example sewing separate pieces together, are required.

(25) The first region R1 and the second region R2 preferably have a linear extent in all directions on the surface of the upper that is significantly larger than a separation of two adjacent loops along a weft direction. By “significantly larger” it is meant in this context, at least a factor of 3 larger, preferably a factor of 5 larger. In other words, the first region R1 and the second region R2 cover parts of the upper that are significantly larger than the mesh size of the knitted fabric. Therefore, regions of support can be engineered on a scale that is significantly larger than the mesh size of the knitted fabric. This is functional because anatomic features of the foot are significantly larger than a mesh size of the knitted fabric. In order for this to be possible, relatively elastic yarns, or threads, need to be used as disclosed herein.

(26) The knitted upper 11b is essentially seamless. The connection lines 12 connecting different regions, portions or parts of the upper 11b, that differs for the knit structures, the yarns or the number of layers, are all obtained during the knitting process. A connection line 12 in this context is therefore any linear interface between any two regions, portions or parts comprising different yarns, different numbers of plies and/or a different number of knitted layers and/or a different knitting structure. Various elements, such as for instance reinforcement elements such as pads, trademark elements, identification labels or care labels, may be sewn in and therefore result in a sewn seam. Connection lines 12 have the advantage that they could be formed within the same process step as the rest of the upper is being formed. A separate step in which two or more pieces are sewn together is not required. Furthermore, the wearing comfort is improved as connection lines 12 do not protrude from the fabric as the sewn seams, and no stitching yarn is required which has different, and often less comfortable properties than the fabric.

(27) In region R2, the two layers are preferably interconnected. The stability of the knitted fabric is improved by connecting the layers and the risk of the layers tearing apart is greatly reduced. The layers are preferably connected directly during the knitting process, which has the advantage of forming a very stable connection that does not require any adhesive, shrink yarn, or fuse yarn. However, it is also possible that the layers are connected after the knitting process is completed in a second consolidation step.

(28) The upper 11b further comprises at least one activated shrink yarn. A shrink yarn is incorporated in an inactive state into the knitted fabric. In the inactive state the knitted fabric including the shrink yarn has a certain area A1, when the shrink yarn is activated, the knitted fabric obtains a new area A2 which is smaller than A1, that is the knitted fabric reduces its area, i.e. shrinks, when the shrink yarn is activated. Preferably, the knitted fabric including the shrink yarn is capable of shrinking at least 15%, and more preferably at least 30%.

(29) Usually activation happens above a certain threshold temperature by exposing the shrink yarn to dry heat or wet heat. Hot steam is a preferred method of activating a shrink yarn as it penetrates deeply and uniformly into the fabric and the yarn fibers. It also prevents damage to the dyes in the fabric and hence the colors of fabric treated with hot steam have a more appealing visual appearance than the colors of the fabric that is exposed to dry heat at the same temperature. The shrink yarn remains in the activated state, that is the shrunk state, even after cooling down and when it is no longer exposed to heat or heated steam.

(30) The knitted unconsolidated upper is preferably arranged on a last and lasted. The knitted unconsolidated upper may be fixed to the last by any suitable means of fixing in order to prevent an unintended movement of the upper during the lasting operation. For example, the upper may be fixed on the last by means of a clamp or a tack. The upper is then exposed to dry or wet heat while it is arranged on the last. The shrink yarn is activated and thus shrinks and provides a close fit of the upper to the last, even in challenging regions. In case that hot steam is used to activate the shrink yarn, the upper may then be dried, preferably in the controlled environment of a drying oven. The upper is then cooled down and removed from the last. It is also possible to cool the upper on the last first, remove the upper from the last, and then dry the upper after it has been removed from the last. The resulting consolidated upper 11b is shown in FIG. 1A and has sufficient permanent rigidity to retain its shape, i.e. it can stand without additional support.

(31) The shrink yarn allows difficult geometric shapes, such as for instance the curvatures at the Achilles tendon or at the toe region, that would be difficult or impossible to obtain in a pure knitting operation, to be formed and consolidated, that is, fixed permanently. The activated shrink yarn also improves the structural strength of the upper in any region into which it has been incorporated.

(32) A shrink yarn also makes it possible to produce up to three adjacent sizes or half sizes of an upper from a single size of a knitted, unconsolidated upper. The sizes can be measured in a UK, US, or European unit system. This simplifies the production process, as a knitted upper and the corresponding knitting model do not have to be generated for every final size of the consolidated upper.

(33) The activated shrink yarn may be arranged at least in a heel and/or a toe portion of the upper 11b. The heel and/or toe portion of an upper are, usually, are in fact the most difficult regions to shape. Moreover, a foot requires increased levels of support in the heel and/or the toe region. The heel and/or the toe region are also critical regions that determine how well and comfortably an upper fits a wearer's foot.

(34) The upper 11b preferably further comprises at least one melted fuse yarn. A fuse yarn, otherwise known as melt yarn, is any yarn that comprises a meltable, generally thermoplastic, component.

(35) A fuse yarn is a useful means to permanently fix the shape of a shaped upper 11b. It also provides additional structural strength in regions where this is required. It is particularly useful to control or limit the shrinkage caused by activating a shrink yarn.

(36) The melted fuse yarn is preferably arranged in a heel and/or a toe portion of the upper. For instance, the fuse yarn may be incorporated in the upper 11b on the toe counter region Y8, on the metatarsal region Y3 and on the heel region Y1. The heel and/or toe portion of an upper are, usually, the most difficult regions to shape. Moreover, a foot requires increased levels of support in the heel and/or the toe region.

(37) The upper 11b shown in FIG. 1A comprises a third region R3. The third region is formed by knitting a collar in the heel region and extending the collar so that it extends beyond the final shape of the upper. The part of the collar that extends beyond the final shape of the upper is then folded back into the upper in the heel region of the upper. In the lasting and consolidation process described herein, these two parts of the collar are shaped together through the activation of the shrink yarn after folding. The two parts keep in this manner their shape and the relative position also when the upper is removed from the last. Optionally, the two parts can be permanently bonded together either by means of melting of the fuse yarn incorporated in the upper or by means of an adhesive or by sewing. A cushioning or a reinforcing material may also be inserted between the two parts. The heel region thus formed is very stable and provides a good level of support for a wearer's foot. This is also illustrated in FIG. 3A for a further example.

(38) FIG. 1B shows a bottom region of the upper 11b. Region R1 of the upper 11b comprises two portions, wherein the first portion P1 comprises a thread having a first number of plies and wherein the second portion P2 comprises the same thread having a second number of plies which differs from the first number of plies. This provides an additional way of tuning the properties, in particular the stability, strength, weight, and breathability of the upper 11b. Differently than the embodiment illustrated in FIG. 1B where the portions P1 and P2 incorporate the same yarns, the first portion P1 may comprise a thread of a first type and the second portion P2 may comprise a thread of a second type.

(39) The number of plies of the thread of the second portion P2 is greater than the number of plies of the thread of the first portion P1. The advantage is that basic properties of the thread such as its look, the feel, and the friction are the same but an additional level of stability is provided on the second portion P2 due to the larger number of plies. Portion P2 of the fabric knitted with the thread having a greater number of plies will be less elastic and stronger than portion P1 of the fabric knitted with the thread having a lower number of plies.

(40) In the embodiment illustrated in FIG. 1B, the first portion P1 extends along the longitudinal axis of the upper from the toe region to the heel region on a central area of the bottom region. The second portion P2 also extends along the longitudinal axis of the upper from the toe region to the heel region, at the sides of the first portion P1.

(41) The number of plies of the thread on the second portion P2 is preferably at least twice as large as the number of plies of the thread on the first portion P1, for example the thread in region P2 has 2 plies of yarn while the thread in region P1 has 1 ply of the same yarn. The inventors have discovered that this factor in the number of plies of the thread on the second portion P2 and the thread on the first portion P1, provides the thread on the second portion P2 with a preferred level of increased structural strength while at the same time the thread on the first portion P1 is still sufficiently strong, yet lightweight. This way, the rim region where portion P2 is located, which is subject to greater shear stresses and forces when the upper is being worn, is provided with a stronger thread. The central region, where portion P1 is located, which is subject to lower shear stresses and forces when the upper is being worn, is provided with a more lightweight construction.

(42) The upper 11b is knitted on a flatbed knitting machine comprising at least two needle beds. A flatbed knitting machine allows a great variety of complex knitting patterns to be incorporated into the knitted fabric. A flatbed knitting machine comprising at least two needle beds allows the upper to be manufactured as one unitary piece in a single knitting operation. Further processing steps, in which separate parts of the fabric have to be sewn together, can therefore be completely avoided. Furthermore, the upper 11b so obtained is substantially seamless, which improves the comfort of the upper 11b.

(43) When the three-dimensional upper 11b is knitted on a flatbed knitting machine comprising two needle beds, according to the tubular knitting technique, during the knitting there is a transfer of yarns from a first needle bed to a second needle bed when changing a knitting stroke direction and such transfer defines, on the finished upper, a parting line 13. In this example, the parting line 13 is arranged between a bottom and a top region of the upper.

(44) A longitudinal direction 14 of the upper is illustrated in FIG. 1B.

(45) FIGS. 2A, B show another exemplary upper 11b according to the invention. The knitted upper 11b is for an article of footwear and is formed essentially as a single piece in a three-dimensional knitting process and comprises at least one activated shrink yarn. FIG. 2A shows a top region of the upper 11b and FIG. 2B shows a bottom region of the upper 11b. The upper 11b comprises a first region R1 comprising one knitted layer and a second region R2 comprising two knitted layers.

(46) At least one of the regions preferably comprises two parts, wherein the first part comprises a first knitting structure and the second part comprises a second knitting structure. The terms knitting structure and knitting patterns are used interchangeably. A knitting structure is, for example, plain, interlock, jersey, purl, rib knit, Milanese, Raschel, or tricot. These terms have their usual meaning. For example, interlock is a stitch in which loops of a first course are situated on every other wale, e.g. wale 1, 3, 5, etc. Loops of the next course, the second course, are situated on the wales skipped in the first course, e.g. 2, 4, 6, etc. Front and back of the interlock fabric look identical. The surface is smooth and soft to touch and the resulting fabric is strong and wear resistant.

(47) The embodiment illustrated in FIG. 2A, for instance, comprises a first part P11 on the instep region having a rib structure for enhancing the stretchability, a second part P12 surrounding the instep region and having a plain fabric structure for enhancing the stability and a third part P13 on the forefoot region having an open structure provided with a plurality of apertures for enhancing the breathability.

(48) The first part P11 may further comprise a plurality of elastic inlays that are incorporated in the knitted structure to improve the fitting of the upper on the foot of a wearer.

(49) This is an additional way of tuning the properties, in particular the elasticity, stability, strength, weight, and breathability of the upper. It has the advantage that the same yarn and the same number of plies may be used for both of the two portions, which is important because the number of different types of yarn or plies is limited by the number of yarn carriers. However, it is also possible that different types of yarn or yarns with different number of plies are used for the two parts.

(50) The upper 11b preferably further comprises at least one melted fuse yarn. A fuse yarn, otherwise known as melt yarn, is any yarn that comprises a meltable component.

(51) A fuse yarn is a useful means to permanently fix the shape of a shaped upper 11b. It also provides additional structural strength in regions where this is required. It is particularly useful to control or limit the shrinkage caused by activating a shrink yarn. It is, for example, possible that no shrinkage is desired at all in certain portions of the upper, where fixation and additional structural support are nonetheless required.

(52) The melted fuse yarn is preferably arranged in a heel and/or a toe portion of the upper. The heel and/or toe portion of an upper are, usually, the most difficult regions to shape. Moreover, a foot requires increased levels of support in the heel and/or the toe region.

(53) A summary of the different knitting structures used for the upper 11b shown in FIGS. 2A, B is given in Table 1. The terms have their usual meaning unless mentioned otherwise.

(54) TABLE-US-00001 TABLE 1 Portion Description P11 Elastic inlay, double layer Jacquard P12 Double layer, plain structure P13 Double layer, open structure P14 Single layer plain structure P15 Single layer, plain structure P16 Single layer, 1 × 1 interlock P17 Single layer, 1 × 1 interlock P18 Single layer, mirrored collar, plain structure P19 Single layer, plain structure P20 Single layer, 1 × 1 interlock

(55) FIGS. 3A, B show another exemplary upper 11b according to the invention. The knitted upper 11b is for an article of footwear and is formed essentially as a single piece in a three-dimensional knitting process and comprises at least one activated shrink yarn. FIG. 3A shows a top region of the upper 11b and FIG. 3B shows a bottom region of the upper 11b. The upper 11b comprises a first region R1 comprising one knitted layer and a second region R2 comprising two knitted layers.

(56) The upper 11b shown in FIGS. 3A, B comprises a folded collar 23 in the heel region. The collar is produced by knitting and extending the collar so that it extends beyond the final shape of the upper. The part 22 of the collar that extends beyond the final shape of the upper is then folded back into the upper in the heel region of the upper. In the lasting and consolidation process described herein, the two parts of the collar are shaped through the activation of the shrink yarn after folding. The two parts of the collar can moreover be bonded in the same lasting and consolidation process through the activation of the fuse yarn or, in a subsequent process step, through gluing or stitching. The heel region thus formed is very stable and provides a good level of support for a wearer's foot.

(57) A summary of the different knitting structures and yarns used for the upper 11b shown in FIGS. 3A, B is given in Table 2. The notation is the same as used for the other tables herein.

(58) TABLE-US-00002 TABLE 2 Portion Description P21 Double layer Jacquard, rib structure with inlay P22 Double layer Jacquard, plain structure P23 Double layer Jacquard, open structure P24 Single-layer, plain structure P25 Single-layer, plain structure P26 Single-layer, 1 × 1 interlock P27 Single-layer, 1 × 1 interlock P28 Mirrored and folded collar, single layer, plain structure P29 Single layer, plain structure P30 Single layer, 1 × 1 interlock

(59) FIGS. 4A, B show another exemplary upper 11b according to the invention. FIG. 4A shows a top region of the upper 11b and FIG. 4B shows a bottom region of the upper 11b. The upper 11b comprises a first region R1 comprising one knitted layer and a second region R2 comprising two knitted layers. In particular, the first region R1 comprises a central area P41, incorporating a first yarn and extending centrally from the toe region to the heel region, and a side areas, incorporating a second yarn and extending longitudinally at the sides of the central area P41. The second yarn has a greater number of plies than the first yarn.

(60) The upper 11b shown in FIGS. 4A, B comprises a folded collar P36 in the heel region.

(61) FIGS. 5A-C show a further embodiment of a knitted upper 11a and shoe according to the present invention. FIG. 5A shows a top view and FIG. 5B shows a lateral view of the knitted upper 11a in a flat state immediately after knitting. The upper 11a is knitted on a flatbed knitting machine comprising at least two needle beds.

(62) The upper 11a shown in FIGS. 5A and 5B comprises a third region R3 that is formed by knitting a collar in the heel region and extending the collar so that it extends beyond the final shape of the upper. The part of the collar that extends beyond the final shape of the upper is then folded back into the upper in the heel region of the upper, as described above for the upper of FIG. 1A.

(63) The knitted unconsolidated upper 11a is then arranged on a last and lasted (step not shown). The upper is then exposed to heat or heated steam while it is arranged on the last. The shrink yarn is activated and thus shrinks and provides a close fit of the upper to the last, even in challenging regions. The fuse yarn is melted. In this example, steam is used to activate the shrink yarn and the upper may be dried in the controlled environment of a drying oven. The upper is then cooled down and removed from the last. The resulting upper has a set shape and form that provides an excellent fit to a foot.

(64) In a further process step, a sole 52 is attached to the consolidated upper 11b, resulting in the shoe 51 shown in FIG. 5C.

(65) The upper according to the invention may comprise holes for shoe laces. The holes can be integrally formed within a single knitting process. No additional sewing or re-enforcement of the region around the holes is required.

(66) FIG. 6A shows an exemplary unconsolidated upper 11a arranged on a shoe last 61. The upper 11a is preferably fixed to the last 61 with a means of fixing. The knitted unconsolidated upper 11a may be fixed to the last by any suitable means of fixing in order to prevent an unintended movement of the upper during the lasting operation and/or during the subsequent heat treatment. For example, the upper may be fixed on the last by means of a clamp or a tack.

(67) FIG. 6B shows how the upper 11a arranged on the last 61 is inserted into a chamber 62. The chamber is then closed as shown in FIG. 6C and the upper 11a is heated. The shrink yarn is activated and thus shrinks while the upper is on the last and therefore facilitates a close fit of the upper to the last, even in challenging regions. The fuse yarn is melted. The upper 11a is then cooled down to consolidate the lasted shape and then removed from the last 61. The fuse yarn is preferably melted in the same process step as the shrink yarn is activated to reduce the number of process steps. However, it is possible that the operations of melting the fuse yarn and activating the shrink yarn are performed separately, for example, if the activation temperature of the shrink yarn is different to the melting temperature of the fuse yarn. This may be beneficial to allow a partial consolidation of the upper 11a and further processing steps.

(68) Heating the upper 11a on the last 61 is preferably performed using hot steam in a steaming chamber 62. In this case, an additional step of drying the upper 11b may be performed, preferably in the controlled environment of a drying oven. It is also possible to cool the upper 11a on the last 61 first, remove the upper 11b from the last 61, and then dry the upper 11b after it has been removed from the last 61. It is also possible that the upper 11b is dried while it is still on the last, either before a first cool down or after it has cooled down once or several times already. Hot steam is a preferred method of activating a shrink yarn as it penetrates deeply and uniformly into the fabric. It also prevents damage to the dyes in the fabric and hence the colors of fabric treated with hot steam have a more appealing visual appearance than the colors of the fabric that is exposed to dry heat at the same temperature.

(69) FIGS. 7A, B illustrate the behavior of a shrink yarn 72. FIG. 7A shows an inactive shrink yarn 72a before it is activated. The shrink yarn is held fixed at both ends by a suitable construction 71. FIG. 7B shows the activated shrink yarn 72b after it has been activated as described herein. The shrink yarn has shrunk and is now under tension.

(70) The use of a shrink yarn, especially in combination with a lasting operation, allows even difficult geometric shapes, that would be difficult or impossible to obtain in a pure knitting operation, to be formed and consolidated, that is, fixed permanently. The activated shrink yarn and the melted and solidified fuse yarn also improves the structural strength of the upper in any region into which it has been incorporated.

(71) A shrink yarn also makes it possible to produce up to three adjacent sizes or half sizes of an upper from a single size of a knitted, unconsolidated upper. This simplifies the production process, as a knitted upper and the corresponding knitting model do not have to be generated for every final size of the consolidated upper.

(72) FIG. 8 shows an exemplary knitted textile for an upper according to the present invention. The knitted textile is shown prior 80a to activating the shrinking yarn and after 80b activating the shrinking yarn. Prior 80a to activating the shrinking yarn the knitted textile has a width 81a of 150 mm and a height 82a of 155 mm and therefore an area of 23,250 square millimeters. After 80b activating the shrinking yarn the knitted textile has a width 81b of 125 mm and a height 82b of 130 mm and therefore an area of 16,250 square millimeters. The area of the knitted textile is therefore shrunk by 30% by activating the shrinking yarn.

(73) The knitted textile has a width of 150 needles per course and a length of 160 wales. The yarn used comprises air tack yarn comprising four plies of 150 denier polyester yarn and 40 denier elastane yarn. Moreover, a filament single ply 600 denier polyester yarn is used.

(74) FIG. 9 illustrates an exemplary air tack yarn 72a suitable for an upper and a method for production thereof according to the present invention. The exemplary air tack yarn 72a comprises a filament yarn 92 comprising polyester and having a plurality of filament fibers 96 and an elastane strand 91. A tacking width 93 is given by the separation of adjacent tacking point 94. A strong air tack yarn results from a tacking width 93 of between 3 and 20 mm, preferably between 5 and 15 mm, measured when the elastane strand is relaxed. A yarn crimp is illustrated with reference numeral 95. Yarn crimp in %=(straightened yarn length−relaxed yarn length)/(straightened yarn length)×100. Preferably, yarn crimp is in the range between 20% and 100% in order to provide advantageous shrinking properties and sufficient stability. In this example, the denier ratio between polyester yarn and elastane yarn is 3.75:1. There are between 24 and 1152 filament fibers per polyester yarn.

(75) FIG. 10 illustrates the transfer 104 of yarn between a first needle bed 102 and a second needle bed 103 during a knitting operation on a flat knitting machine. When the three-dimensional upper is knitted on a flatbed knitting machine comprising two needle beds, according to the tubular knitting technique, during the knitting there is a transfer 104 of yarns from a first needle bed to a second needle bed when changing a knitting stroke direction and such transfer 104 defines, on the finished upper, a parting line. The top indicates the stitches created on the first needle bed 102 with a first stroke, from right to left, and the bottom indicates the stitches created on the second needle bed 103 with a second stroke from left to right. Reference numeral 105 indicates needles knitting.

(76) FIG. 11 illustrates an exemplary simplified knitting sequence for knitting a part or a portion of an upper according to the present invention, in particular comprising a double layer jacquard on the top and/or on the bottom layer. The exemplary knitting sequence is for knitting on a flatbed knitting machine comprising a first 102 and a second 103 needle bed. Reference numeral 105 generally indicates needles knitting, reference numeral 104 indicates a spacer structure.

(77) At the bottom 108, the sequence illustrates how a top layer is knitted. The top layer is knitted using needles of both needle beds. The spacer sequence 104 is added to tighten the knitting structure of the top or bottom layer that is being knitted.

(78) Reference numeral 111 indicates a tuck stitch.

(79) At the top, an inlay portion is illustrated. The needles 106 on the first 102 and the second 103 needle bed are not knitting. Reference numeral 107 indicates the inlaid yarn.

(80) In order to further knit the bottom layer, part of the needles on the front and back needle beds that have been used to knit the top layer need to be freed. This is realized by means of transfers (not illustrated) of part of the knitted stitches from the back to the front needle bed or vice versa before proceeding knitting the bottom layer.

(81) FIG. 12 shows another exemplary upper 11b according to the present invention. In particular, the exemplary upper 11b comprises two knitted layers 123 all over the upper 11b. Moreover, the exemplary upper 11b comprises a Jacquard knit portion 122 and an engineered amount of stretch in a metatarsal region 121. The exemplary upper 11b also comprises a parting line 13, as described herein. Knitted portion 125 provides an interesting perceived transparency, while silhouette portion 124 allows a good level of breathability.

(82) Some embodiments described herein relate to a knitted upper for an article of footwear formed essentially as a single piece in a three-dimensional knitting process and including at least one activated shrink yarn.

(83) In any of various embodiments described herein, the knitted upper may further include at least one melted fuse yarn. In some embodiments, the melted fuse yarn may be arranged in a heel and/or toe portion of the upper.

(84) In any of various embodiments described herein, the upper may be produced on a flatbed knitting machine comprising at least two needle beds.

(85) In any of various embodiments described herein, the knitted upper includes a first region having a first number of knitted layers, and a second region having a second number of knitted layers, wherein the second number of knitted layers is larger than the first number of knitted layers. In some embodiments, the first region and/or the second region have a linear extent in all directions on the surface of the upper that is significantly larger than a separation of two adjacent loops along a course direction. In some embodiments, in any region having a number of layers greater than one, the layers may be interconnected. In some embodiments, at least one of the first region and the second region has at least two portions, wherein a first portion includes a yarn of a first type and the second portion includes a yarn of a second type.

(86) In any of various embodiments described herein, the knitted upper may include at least a first yarn and a second yarn, and a number of plies of the second yarn is greater than a number of plies of the first yarn. In some embodiments, the number of plies of the second yarn is at least twice as large as the number of plies of the first yarn.

(87) In any of various embodiments described herein, at least one of the first region and the second region includes at least two parts, wherein a first part includes a first knitting structure and a second part includes a second knitting structure.

(88) In any of various embodiments described herein, the activated shrink yarn may be arranged at least in the first region.

(89) Some embodiments described herein relate to a method of producing a knitted upper for an article of footwear that includes knitting at least one activable shrink yarn into the upper, knitting the upper essentially as a single piece in a three-dimensional knitting process, arranging the knitted upper on a shoe last, and activating the shrink yarn.

(90) In any of various embodiments described herein, the activable shrink yarn may include at least one air-tack yarn.

(91) In any of various embodiments described herein, the activable shrink yarn may be arranged in a heel and/or a toe portion of the upper.

(92) In any of various embodiments described herein, at least one fuse yarn may be arranged in a heel and/or a toe portion of the upper.

(93) In any of various embodiments described herein, the method of producing a knitted upper may further include knitting a first region comprising a first number of knitted layers, and knitting a second region comprising a second number of knitted layers, wherein the second number of knitted layers is larger than the first number of knitted layers. In some embodiments, the first region and/or the second region have a linear extent in all directions on the surface of the upper that is significantly larger than a separation of two adjacent loops along a course direction.

(94) In any of various embodiments described herein, the method of producing a knitted upper may further include interconnecting the layers in any region comprising a number of layers greater than one.

(95) In any of various embodiments described herein, the first region may be at least partially located in a bottom region of the upper and/or a heel region of the upper and the second region may be located in a top region of the upper.

(96) In any of various embodiments described herein, at least one of the first region and the second region may include at least two portions, wherein a first portion includes a yarn of a first type, and wherein a second portion includes a yarn of a second type.

(97) In any of various embodiments described herein, at least a first yarn and a second yarn may be knitted into the upper, wherein a number of plies of the second yarn is greater than a number of plies of the first yarn. In some embodiments, the number of plies of the second yarn may be at least twice as large as the number of plies of the first yarn.

(98) In any of various embodiments described herein, at least one of the first region and the second region includes at least two parts, wherein the first part includes a first knitting structure and the second part includes a second knitting structure.

(99) In any of various embodiments described herein, the first region includes one knitted layer and the second region includes two knitted layers.

(100) In any of various embodiments described herein, the method of producing a knitted upper includes knitting at least two uppers simultaneously on the same knitting machine.