阅读说明：本技术 用于形成鞋类中底的方法 (Method for forming a footwear midsole ) 是由 胡安·曼努埃尔·卡列 于 2019-08-22 设计创作，主要内容包括：提供了用于形成鞋类制品的方法和系统。在一个实例中,形成鞋类制品包括在模制鞋类制品的中底间使用穿孔鞋楦。中底可以附接到鞋类制品的鞋面的接缝以将中底紧固到鞋面。(Methods and systems for forming an article of footwear are provided. In one example, forming the article of footwear includes using a perforated last between midsoles of the molded article of footwear. The midsole may be attached to a seam of an upper of the article of footwear to secure the midsole to the upper.)

1. A method for forming an article of footwear, comprising:

positioning a perforated last relative to a cavity of a mold; and

injecting a material configured to form a foam into the cavity to form a sole that is directly attached to an upper surrounding the perforated last.

2. The method of claim 1, wherein injecting the material into the cavity forms a midsole disposed between the upper and an outsole, and wherein the material is injected through an inlet port of the mold, the inlet providing a single source of entry of the material into the cavity.

3. The method of claim 2, wherein forming the midsole comprises: enclosing the material of the sole within a continuous, non-breathable surface of the mold that does not include an opening other than the inlet port, and sealing the material of the midsole within the surface of the cavity of the mold when a bottom piston of the mold is raised while allowing gas to flow from the midsole through perforations of the perforated last to an internal conduit of a last that forms an opening at the top of the last.

4. The method of claim 3, further comprising flowing a gas from the midsole through the perforations to a manifold that fluidly couples the perforations to the internal conduit, and wherein the internal conduit is coupled to a vacuum source.

5. The method of claim 2, further comprising mounting an upper of the article of footwear to the perforated last.

6. The method of claim 5, wherein mounting the upper onto the perforated last comprises: inserting the perforated last into the upper attached to a seam footbed, the seam footbed being coupled to the upper by a blind seam extending around a perimeter of the footbed.

7. The method of claim 6, wherein attaching the midsole to the upper comprises: curing the foamed material around a seam allowance of the blind seam, the seam allowance extending downward into the midsole.

8. The method of claim 5, wherein mounting the upper onto the perforated last comprises: positioning an insole between the upper and the perforated last and covering a bottom surface of the perforated last with a bottom area of the insole, the insole being formed of a breathable material.

9. The method of claim 8, wherein attaching the midsole to the upper comprises: joining the foamed material with the bottom region of the insole such that the foamed material is in direct contact with a seam extending around a perimeter of the bottom region of the insole.

10. The method of claim 9, wherein attaching the midsole to the upper comprises: penetrating the foamed material through gaps between strobel stitches forming the seam of the insole and through apertures of material of the upper into an interior of the article of footwear; and curing the foamed material, wherein a portion of the foamed material is disposed in the interior of the article of footwear and is coupled to the midsole through the gap via an extension of the foamed material.

11. A system for forming a shoe, comprising:

perforating a shoe tree;

a mold having a cavity shaped to receive a bottom region of the perforated last; and

an injection machine configured to couple to an inlet port in the mold and to inject a material configured to foam and form a sole.

12. The system according to claim 11, wherein the perforated last has a plurality of perforations extending through a thickness of a wall of the perforated last, the plurality of perforations fluidly coupling air inside an interior conduit of the perforated last to air outside the perforated last, and wherein the plurality of perforations are concentrated adjacent to an area of the midsole where an increase in the sole thickness is desired.

13. The system according to claim 12, wherein the plurality of perforations extend from an upper surface of the perforated last to a bottom surface of the perforated last.

14. The system according to claim 12, wherein the plurality of perforations extend a portion of a distance between upper and bottom surfaces of the perforated last, and wherein the plurality of perforations are fluidly coupled to air surrounding the perforated last through a plurality of internal passages of the perforated last when the perforated last is positioned in the cavity of the mold.

15. The system according to claim 12, wherein the internal conduit of the perforated last is adapted to be coupled to a vacuum source, and the internal conduit extends through an interior of the perforated last to an opening at a top of the perforated last, and wherein the internal conduit is a channel for drawing gas from the foamed material of the sole, wherein the internal conduit is positioned between the perforations of the perforated last and the vacuum source.

16. The system of claim 11, wherein a seam formed by strobel stitches spaced apart from each other connects the upper of the shoe to an insole, and wherein a portion of the foamed material is disposed inside the shoe along the seam of strobel stitches and is coupled to the sole by ligaments of foamed material extending through gaps between the strobel stitches.

17. The system of claim 11, wherein a blind seam connects the upper of the shoe to the footbed of the shoe with a seam allowance extending downward into the sole, and wherein the sole is bonded to the seam allowance and the foamed material of the sole is retained within the sole below the seam footbed.

18. A sole for an article of footwear, comprising:

a foamed material;

a seam positioned over and in direct contact with the foamed material, the foamed material curing around the seam and forming a mechanical coupling with the seam without the use of an adhesive; and

a surface that is impermeable to the foamed material and in coplanar contact with an upper surface of the foamed material, wherein the midsole is free of large bubbles, air pockets, and voids.

19. The sole of claim 18, wherein the foamed material is polyurethane.

20. The sole of claim 18, wherein connecting the foamed material with a perforated last during formation of the sole vents gases generated during curing of the foamed material.

Technical Field

The present specification relates generally to methods and systems for forming a footwear sole directly onto a lasting upper.

Background

A sole (e.g., midsole) is a component of a shoe and may be attached to an upper. The sole may provide cushioning and stability to the shoe, and particularly for athletic footwear, may absorb shock and control excessive foot motion, such as pronation and supination. The durability and aesthetic appearance of the midsole may be affected by the manufacturing process of the midsole.

Disclosure of Invention

A method for forming a sole (e.g., midsole) of a shoe may include perforating a last. The perforated last may allow gases generated during the chemical reaction that forms the midsole to be vented. The midsole may be attached to the upper of the shoe by adhering to the bottom edge of the upper or by penetrating through the stitching (stabbing) of the insole. The resulting shoe sole may include improved properties. A perforated last may also be provided.

It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. The above summary is not intended to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

Drawings

Fig. 1 illustrates an example of a shoe having an upper and a sole structure.

Fig. 2 shows an exploded view of an example of a shoe.

Fig. 3 shows a side view of a first example of a perforated last.

Fig. 4 shows a bottom view of the perforated last.

Fig. 5 shows an example of a first step in the manufacturing process of the shoe.

Fig. 6 shows an example of a second step in the manufacturing process of the shoe.

Fig. 7 shows an example of a third step in the shoe manufacturing process.

Fig. 8 shows a cross-section of a second example of a perforated last positioned over a mold during sole formation.

Fig. 9 shows a cross-section of a third example of a perforated last positioned over a mold during sole formation.

Fig. 10 shows a cross-sectional view of a first example of a method for attaching a sole to an upper of a shoe.

Fig. 11 shows a cross-sectional view of a second example of a method for attaching a sole to an upper of a shoe.

Fig. 12 shows an example of a method for manufacturing a shoe.

Fig. 13 shows a cross-section of a fourth example of a perforated last positioned over a mold during sole formation.

Fig. 1 to 11 and 13 are shown substantially to scale.

Detailed Description

The following description relates to systems and methods for manufacturing articles of footwear, and in one example, to systems and methods for manufacturing athletic footwear. One example of a shoe is shown in fig. 1. The footwear may include an upper attached to the sole structure. The sole structure includes one or more of an insole, a midsole, and an outsole. The components of the sole structure and the upper of the shoe are depicted in an exploded view in fig. 2 to illustrate the ordering and geometry of the shoe elements. The midsole may be formed via injection molding, including mounting the upper on a perforated last to attach the midsole to the upper. One example of a perforated last is shown in fig. 3-4, illustrating the positioning of the perforations along the surface of the last. The perforated last may be used in a process for forming a midsole and attaching the midsole to an upper of a shoe. The steps of this process are shown in fig. 5-7, illustrating the use of a mold into which the foamed material of the midsole may be injected or open cast, with the upper mounted on a perforated last, positioned above the midsole and the outsole disposed below the midsole. A cross-section of an embodiment of the perforated last is shown in fig. 8-9 and 13, depicting the positioning of the perforated last relative to the cavity of the mold and the geometry of the inner conduit of the perforated last during formation of the midsole. The foamed material of the midsole may be attached to a seam footbed of the insole or upper of the footwear when cured. A method of attaching a midsole to an upper by curing the midsole to an insole and a seam footbed is shown in the cross-sectional views of fig. 10-11 and 8, respectively illustrating a method of including a strobel seam of an insole and a method of including a blind seam of a seam footbed. One example of a method for manufacturing a shoe is provided in fig. 12, including using a perforated last and injection molding, open casting, or casting for forming the midsole.

Footwear, and particularly athletic footwear, may include an upper and a sole structure. When the upper covers the foot and securely positions the foot with respect to the sole structure, the sole structure is positioned beneath the foot and provides a barrier between the foot and the ground. The sole structure may attenuate ground reaction forces, provide traction and stability, and control foot motions. By attaching the upper to the sole structure to form a shoe, the foot may be surrounded and supported by the shoe such that the wearer may comfortably participate in recreational activities, such as walking and running.

The sole structure may be formed from one or more laminates that include an insole, a midsole, and an outsole. The insole may be the topmost layer positioned in the upper and configured to be adjacent to a plantar surface or pad of the foot and comfortably engage the foot. The midsole may be secured to the upper along a length of the upper and forms a middle layer of the sole structure between the insole and the outsole. Cushioning, stability, and motion control are imparted to the wearer's foot by the midsole. The outsole is the lowest layer of the sole structure and contacts the ground as it is positioned below the midsole. The outsole may be formed of a durable, rugged material that is textured to provide traction for the shoe. The exemplary layers are for illustration purposes, and one or more of them may comprise multiple components and/or layers, or may be divided into continuous and/or discontinuous sections. In addition, various layers may be omitted.

The performance of the footwear may be affected by the characteristics of the midsole. For example, a thicker midsole may be desirable for a highly comfortable wearer who needs to run long distances. A wearer with foot ailments such as plantar fasciitis may choose a shoe with a strong midsole, while off-road runners may use a shoe with a thin midsole to increase the stability of the foot with respect to changes in ground terrain. The secure and comfortable attachment of the midsole to the upper can have a significant impact on the durability of the footwear and the consumer appeal of the footwear. The attractiveness of the shoe may also be affected by the aesthetic characteristics of the shoe, such as a smooth, continuous joint between the unworn surface of the sole structure and a component of the shoe.

The midsole may be formed of a polymer foam material, such as Polyurethane (PU), Ethylene Vinyl Acetate (EVA), rubber, or silicone, and is constructed by compression molding, injection molding, open casting, or the like. For athletic footwear, in one example, the midsole may be formed via an injection molding process that includes injecting a foamed material, such as PU, into a mold and allowing the foamed or foamed material to cure and harden onto the upper. The midsole may be attached to the upper by applying an adhesive, and the outsole may be molded directly to a bottom surface of the midsole, or may be secured to the midsole by an adhesive. Alternatively, during injection of the foamed material, the midsole may be attached directly to the upper during the injection step by positioning the upper over the mold. A last may be inserted into the upper to provide a structural frame for the upper during the injection process. The last may be in a mechanical form having a structure similar to that of the foot and be constructed of a rigid material, such as wood, metal, or high density plastic, or the like, or a combination thereof. The foam material may penetrate through the fibers of the upper and the strobel or blind seam stitching that extends around the perimeter of the interior footbed, thus attaching the midsole to the upper through the gaps in the upper material as the foam material hardens.

The inventors herein have recognized several problems with the above approach. For example, during injection and curing of the foamed material, outgassing may occur which releases large bubbles, air pockets, and/or voids in the midsole material. The large bubbles, air pockets and voids may be air pockets of at least 2mm in diameter. The foamed material may be encapsulated by low porosity surfaces, such as mold surfaces and lasts, causing air bubbles, air pockets, and voids to be trapped within the midsole. The presence of large bubbles, air pockets, and voids in the midsole may present undesirable imperfections on the outer surface of the midsole.

One or more of the above-described problems may be addressed, at least in part, by a method for an article of footwear that includes positioning a perforated last relative to a mold cavity, and injecting a material configured to form a foam into the cavity to form a sole that is directly attached to an upper around the perforated last. In one example, the method includes using a perforated last. The perforations may extend through a thickness of the last to fluidly couple air surrounding the last to air within the interior conduit of the last. During injection molding, open casting, or casting, the perforations may form a fluid coupling between the interior of the mold cavity and the surrounding atmosphere through the last. In addition, the venting release may be assisted via perforations by applying a vacuum to one or more passageways formed in the last. Gas generated during injection molding can escape through the perforations, thereby reducing the likelihood of large bubbles, air pockets, and voids forming.

In addition, a perforated last may be used in conjunction with molding the midsole directly to the upper, with the attachment between the upper and midsole being accomplished by allowing the foam material to permeate through the upper material (e.g., fiber or fabric) or by joining the midsole with the seam footbed of the upper. In addition, even if there are fluid pathways that enable the escape of gases, the sole material is held in place by the footbed or other structure of the sock or upper. This eliminates or minimizes trimming of the sole material that penetrates beyond the desired boundary (e.g., outer shape) of the midsole, thereby further reducing costs associated with manual labor. Additional details and components of the method are set forth in more detail with respect to the description of fig. 1.

Turning now to fig. 1, footwear 100 may include an upper 102 and a sole structure 104. A set of reference axes 101 are provided, indicating the y-axis, x-axis and z-axis. Upper 102 may be disposed above sole structure 104 and adapted to allow a foot to be inserted into the void of footwear 100 through opening 106. The foot is held in place in footwear 100 by upper 102 and may directly contact the interior surface of upper 102. In order to provide a comfortable engagement of the foot with upper 102, upper 102 may be constructed of a flexible synthetic material such as polyester, nylon, synthetic leather, or a natural material such as leather. Footwear 100 may also include a sockliner disposed within the void of the footwear along the interior surface of upper 102 and attached to upper 102 by stitching.

Upper 102 may be fitted with a lacing system 108, where lacing system 108 includes a set of laces that pass through apertures in upper 102 along an area of upper 102 adjacent an instep of the foot when footwear 100 is worn. In other examples, upper 102 may have a velcro attachment without lacing system 108, or neither lacing system 108 nor a velcro attachment. The lacing system may be used to tighten the upper around the foot and enhance the securement of the foot inside footwear 100.

Upper 102 may be secured to sole structure 104 along bottom edge 110. The sole structure may include an insole, a midsole 112, and an outsole 114 positioned along a footbed of the footwear inside the cavity of the footwear 100. The midsole 112 is directly adjacent to and above the outsole 114 such that the midsole 112 and the outsole 114 are in coplanar contact, the common plane being coplanar with the x-z plane. The midsole 112 may be a compressible layer of foamed material, such as Ethylene Vinyl Acetate (EVA), Polyurethane (PU), or Thermoplastic Polyurethane (TPU), and, as discussed above, may be configured to attenuate ground forces and reduce impact transmitted to the foot due to contact of the shoe with the ground. In some examples, the thickness of midsole 112 defined along the y-axis may vary as needed to increase cushioning at certain areas relative to the foot. For example, if footwear 100 is adapted for long distance running, the area under the heel of the foot may be thicker than the area under the ball of the foot. Additionally, the stiffness (stiffness) of the midsole 112 may be non-uniform along the midsole 112 to provide stability or cushioning in desired areas of the midsole 112.

The outsole 114 may have an upper face 116, the upper face 116 being contoured to match a bottom surface 118 of the midsole 112. The bottom surface 120 of the outsole 114 may be textured to provide traction to the footwear 100. The outsole 114 may be formed from a less compressible and more durable material than the midsole 112, such as carbon rubber or blown rubber.

The components of the shoe 202 are shown in an exploded view 200 in fig. 2. The shoe 202 has a toe region 203 and a heel region 205, and includes an upper 204, the upper 204 having a lacing system 206 and an opening 208, and a sole structure 214, the sole structure 214 including a midsole 216 and an outsole 226. Upper 204 may have an attached sockliner (not shown in fig. 2) lining the interior of upper 204, or may be stitched directly to a seam footbed that provides a bottom surface for upper 204. In addition, in some examples, sole structure 214 may also include an insole positioned below upper 204 and above midsole 216 that is contoured to match the shape of the foot. The insole may be disposed over a footbed or seam footbed at the bottom of the interior cavity of the shoe 202, and may be formed of EVA.

Sole structure 214 may be shaped to match the exterior geometry of bottom edge 222 of upper 204. The midsole 216 may have a raised edge 218 around at least a portion of the perimeter of the midsole 216, the raised edge 218 extending above an upper surface 220 of the midsole. The width of the midsole 216, defined along the x-axis, may be wider than the width of the upper 204 and the insole 210, such that the bottom edge 222 of the upper 204 may fit within and be surrounded by the raised edge 218 of the midsole 216.

The portion of the outsole 226 in fig. 2 may have a similar shape as the midsole 216, but the outsole 226 may alternatively comprise multiple segments secured to regions of the bottom surface of the midsole 216. The outsole 226 may be adapted to provide traction in desired areas of the sole structure 214, such as under the ball of the foot. The outsole 226 may be thinner than the midsole 216, as defined along the y-axis. The outsole 226 may be contoured to match the shape of the midsole 216 and include a textured bottom surface 228.

The process of attaching the components of the shoe 202 shown in fig. 2 to form the unitary article of footwear may include using a last. The last may be a structure shaped like a foot and formed of a rigid material, such as wood, metal, or high density plastic. The upper and sole structure of the footwear may be formed around a last, and thus the overall shape of the interior of the footwear may depend on the geometry of the last.

During shoe formation, the upper may be tightly wrapped around the upper portion of the last. The last and upper may be positioned on top of the mold such that the last is in sealing engagement with the top edge of the mold. The foamed material may be injected, open cast, or cast into a cavity of the mold, which may be a sealed chamber as a result of positioning the last over the mold. When the foamed material cures, gas may be generated that remains sealed within the cavity of the mold and within the material of the midsole. The trapped gas may form large bubbles, air pockets, or voids that may be visible along the outer surface of the midsole after curing is complete, leaving undesirable cosmetic defects.

To address the problem of large air bubbles forming in the midsole, a perforated last may be used. A first example of a perforated last 302 is shown in a side view 300 in fig. 3 and a bottom view 400 in fig. 4. The perforated last 302 has an upper portion 304, as shown in fig. 3, which upper portion 304 is shaped to represent the upper area of the foot and the lower area of the ankle. The upper portion 304 of the perforated last 302 has a forefoot portion 303 and a heel portion 305, the forefoot portion 303 representing the instep and toe of the foot, and the heel portion 305 representing the heel of the foot. An upper, such as upper 102 of fig. 1 and upper 204 of fig. 2, and including a sockliner, may be fitted around upper portion 304 of perforated last 302 and fastened to secure the upper in place.

When the perforated last 302 is placed over the mold and the foamed material is injected into the mold to form a midsole, the midsole may conform to the shape of the footbed 306 of the perforated last 302, as shown in fig. 4. The footbed 306 may be a bottom surface of the perforated last 302 and coupled to the upper portion 304 via a curved surface such that the perforated last 302 has a smooth continuous form.

The perforated last 302 may include perforations 308 that extend through the thickness of the perforated last 302. In one example, the perforated last 302 may be substantially hollow, with an internal conduit 312 extending through the perforated last 302, such that the perforated last 302 is a shell having a thickness through which the perforations 308 may extend. In this manner, the air in interior conduit 312 is fluidly coupled to the air surrounding perforated last 302 through perforations 308. In another example, the perforated last 302 may be substantially solid, and the internal conduit 312 extends from an opening at the top of the perforated last 302 down through a portion of a height 330 of the perforated last 302, the height 330 being defined along the y-axis. A manifold disposed within the perforated last 302 may be coupled to the internal conduit 312, fluidly coupled to the internal conduit 312 and extending substantially horizontally (e.g., along the z-axis) through the perforated last 302. Perforations 308 may be fluidly coupled to the manifold, thereby fluidly coupling the air surrounding perforated last 302 to the air inside internal conduit 312.

The perforations 308 may be distributed in different areas of the perforated last 302, such as along the lower edge 310 of the upper portion 304 of the perforated last 302 shown in fig. 3. Perforations 308 may also be provided in footbed 306 of perforated last 302. Perforations 308 may be arranged in clusters or evenly spaced. The cluster of perforations 308 may be positioned in an area where the midsole is expected to be thicker, such as under the heel of the foot along the footbed 306 in the dashed area 314, under the arch of the foot in the dashed area 316, under the ball of the foot in the dashed area 318, or under the toe of the foot in the dashed area 320. The perforations 308 may also collect large air bubbles, air pockets, and/or voids in the midsole that may affect the area of coupling of the midsole with the upper, such as along the lower edge 310 of the upper portion 304 of the perforated last 302 or along the upper surface of the forefoot portion 303 of the perforated last 302, near the perimeter of the perforated last 302, as shown in fig. 3.

It will be appreciated that the perforated last 302 of fig. 3 and 4 is a non-limiting example. Some examples of the perforated last 302 may include perforations 308 arranged in a pattern, spacing, size, geometry, and location relative to the surface of the perforated last 302 that is different than that shown in the present disclosure. Other examples may include different combinations of perforated clusters. For example, the shoe may have clusters of perforations 308 below the toe (dashed area 320) and along the arch (dashed area 316) or below the ball of the foot (dashed area 318) and below the heel (dashed area 314) or just below the ball of the foot. A variety of variations of perforations 308 and aggregation of perforations 308 have been contemplated. Furthermore, some or all of the example passages, connectors, and/or manifolds illustrated in fig. 8-11 and 13 may be incorporated in the last of fig. 3-4.

As described above, perforated last 302 may include internal conduit 312 that extends through perforated last 302 such that perforated last 302 is substantially hollow, while the thickness of perforated last 302 is sufficient to maintain the structural integrity of perforated last 302. Alternatively, the perforated last 302 may be substantially solid, with a relatively short and narrow internal conduit 312, the internal conduit 312 extending through a portion of the perforated last 302 and coupled to the manifold. Perforations 308 extending through the thickness of perforated last 302 may fluidly couple air inside internal conduit 312 to air outside and around perforated last 302. Further details of the geometry of the perforations 308 are shown in fig. 8-9 and further set forth below. The fluid coupling of air inside and outside the perforated last 302 may allow gases formed during curing of the midsole to vent through the perforations 308. The pressure in the midsole due to the out-gassing may equalize over the perforations 308, thereby releasing the gas into the atmosphere. In some examples, the internal conduit of perforated last 302 may be coupled to a vacuum pump to further facilitate evacuation of gas from the bottom during injection of the foamed material.

Vacuum assisted venting of gases may be applied during the shoe manufacturing process. Additionally or alternatively, if desired, it may be vented to the atmosphere without the aid of a vacuum. Furthermore, the level of vacuum applied may be adjusted during the manufacturing process. In one example, the vacuum level may be increased, for example, in response to the formation of defects on the surface of the midsole (which may be automatically identified via a camera/inspection system based on image processing of the molded product).

The perspective views 500, 600, and 700 of fig. 5-7 illustrate a manufacturing process of an example of a method of forming a midsole of a shoe 402 using a perforated last 302 (e.g., the perforated last 302 of fig. 3) and a mold 404, respectively. For illustrative purposes, the mold 404 is shown in fig. 5 and 7 with a portion of the mold cut away. The perforated last 302 may be hollow and include an internal conduit 312, the internal conduit 312 being fluidly coupled to the perforations, such as perforations 308 of the perforated last 302 in fig. 3-4. The shoe upper 406 may fit snugly over the upper portion of the perforated last 302. A footbed may be disposed between the upper and the perforated last 302, the footbed being attached to the perforated last 302 by stitching, glue, or melting.

As illustrated in fig. 5, perforated last 302 may be positioned over cavity 408 in mold 404. The shape of the cavity 408 may be shaped like a footbed of the perforated last 302 at the top of the cavity 408 with respect to the y-axis, and the geometry may vary depending on the desired shape of the midsole as the cavity 408 extends down into the mold 404. For example, the cavities 408 may be configured to impart a curved side, a textured pattern, or widen the midsole in a downward direction away from the upper 406 of the shoe 402 along the x-z plane.

The cavity 408 may extend completely through the thickness of the first half 403 and the second half 405 of the mold 404 defined along the y-axis. The first half 403 may be stacked on top of the second half 405 such that the cavity 408 is aligned by the first half 403 and the second half 405. The second half 405 may include an inlet port 414, the inlet port 414 extending from an edge of the second half 405 of the mold 404 to the cavity 408, the cavity 408 fluidly coupling air surrounding the second half 405 of the mold 404 to air inside the cavity 408. A thin flash 416 may extend around the perimeter of the cavity 408 between the first half 403 and the second half 405 extending a short distance into the cavity 408 of the mold 404. When the material is injected, the flash 416 may seal the cavity 408 and retain the foamed material used to form the midsole so that the foamed material does not leak down over the sides of the outsole 410. Outsole 410 may be disposed in cavity 408 to form a bottom layer of footwear 402.

A vertically movable bottom piston 412, e.g., slidable along the y-axis, the bottom piston 412 being shaped similar to the cavity 408, may be positioned at the bottom of the cavity 408, and may sealingly engage the cavity 408 to form a floor of the cavity 408. Outsole 410 may be preformed and disposed at the bottom of cavity 408 on top of bottom piston 412 with bottom piston 412 in a lowered position, as shown in fig. 5. The upper surface of the outsole 410 may be prepared for attachment to the midsole by roughening the upper surface, priming, and coating the upper surface with an adhesive, such as cement. The bonding agent may be thermally activated prior to forming the midsole.

The perforated last 302 and upper 406 may be lowered to contact the mold 404, as shown in fig. 5. A mixer-injector 418 is inserted into the inlet port 414 and a measured amount of foamed material, such as polyurethane, is introduced through the inlet port 414. The foamed material may initially be a liquid or gel that foams when mixed with the chemical that initiates the foaming reaction, either before or after injection. Alternatively, the material may have been injected at a foam consistency. When the bottom piston 412 is in the lowered position, the amount of polyurethane does not fill the cavity 408 of the mold 404. Injection of the desired amount of polyurethane is achieved by timing the interval during which the gear pumps 422 and 420 are turned on to deliver components a and B to the mixer-injector 418, which in one example can be isocyanate and polyol resin to form polyurethane, the mixer-injector 418 rotates as shown by arrow 601 to mix components a and B. However, in other examples, additional component C, which may be a liquid or a gas, may be included to aid the foaming process.

Upon introduction of mixed components a and B into cavity 408, bottom piston 412 is raised upwardly along the y-axis such that the upper outside edge of outsole 410 engages flash 416, as shown in fig. 7. The inlet port 414 is thereby isolated from the cavity 408 containing polyurethane. The polyurethane foams and expands, filling the interior volume of cavity 408 with bottom piston 412 in the raised position to form midsole 424, and irreversibly couples with the lower edge of upper 406. Outgassing may occur as the polyurethane foams and expands, creating air pockets within the polyurethane in the cavity 408. The gas may be vented through the perforations of perforated last 302, and the venting of the gas may be further facilitated by connecting the internal conduit 312 of perforated last 302 to a vacuum source. Finished shoe 402 may be removed by separating first half 403 from second half 405 of mold 404.

As another example of a manufacturing process, the midsole may be formed by a casting process (e.g., open casting or casting). The bottom piston 412 may be in a raised position, engaged with the flash 416, and the mold 404 assembled such that the first half 403 is stacked on top of the second half 405 to form an open container for receiving polyurethane (or some other type of material configured to foam) as a molten phase. Polyurethane may be poured into cavity 408, and perforated last 302 and upper 406 placed over cavity 408, allowing the polyurethane to adhere to upper 406 as the material cures and hardens.

In this manner, perforated last 302 may provide structural guidance to form a midsole or sole of footwear 402, with a last to midsole and/or sole ratio of 1 to 1. The size of the perforated last 302 thus determines the final size of the midsole/sole of the shoe without adjustments to account for expansion or contraction of the midsole/sole material. Injection molding or open casting or casting of the midsole/sole in a 1:1 ratio allows the midsole/sole to be directly attached to the upper component of the shoe 402 during the forming process.

Although fig. 5-7 show the perforating last in an upright position and positioned above the mold relative to the y-axis, other examples may include different orientations of the perforating last and the mold. For example, the components of fig. 5-7 may be positioned upside down relative to the view shown or in a vertical orientation. Various alignments of the footbed in which the cavity of the mold receives the perforated last have been contemplated and are within the scope of the present disclosure.

A cross-section 800 of a second example of a perforated last 502 is depicted in fig. 8, the perforated last 502 being positioned over the cavity 504 of the mold 506. The mold may be similar to mold 404 of fig. 5-7. As shown, the perforated last 502 is free of an upper of a shoe, such as the upper 406 of fig. 5-7, that is installed. The perforated last 502 may include perforations 508, the perforations 508 being disposed along a footbed 510 of the perforated last 502 and along an upper surface of the perforated last 502. The portion of the perforation 508 proximate the toe region 503 of the perforated last 502 may extend through the material of the perforated last 502 and be fluidly coupled to a manifold 512 in the last, which manifold 512 is in turn fluidly coupled to an internal conduit 514 of the perforated last 502. Another portion of perforations 508 may extend from the exterior surface of perforated last 502 to internal conduit 514, such as perforations proximate heel region 505 of perforated last 502. The manifold 512 may be a channel extending from the toe region 503 of the perforated last to the internal conduit 514 substantially along and at an angle to the z-axis. The internal conduit may extend from an opening 516 at the top of the perforated last 502 down through a portion of the height of the perforated last 502, which is defined along the y-axis. As such, perforated last 502 may be substantially solid, e.g., not hollow.

A vacuum source 515, such as a vacuum pump, may be attached to opening 516 at the top of perforated last 502. When the vacuum source is activated, the vacuum source may create a low pressure area within the internal conduit 514 and manifold 512 of the perforating last 502. Thus, when injected through the foaming material in the direction indicated by arrow 520 through the inlet port 518 to form the midsole, gases generated during the midsole formation process may be forced to evacuate through the perforations 508. When the midsole material is injected in the cavity 504 and the bottom piston 522 is raised, the midsole material may experience outgassing as the volume of the cavity 504 decreases and the foamed material solidifies, similar to the process described in fig. 5-7.

The cavity 504 may be a fully enclosed chamber when the bottom piston 522 is raised so that the inlet port is blocked and air outside the mold 506 does not exchange with air inside the cavity 504. The cavity 504 may be surrounded by the footbed 510 of the perforated last 502, the side surface 524 of the mold 506, and the top surface 526 of the bottom piston 522. The side surface 524 of the mold 506 and the top surface 526 of the bottom piston 522 may be a continuous surface that blocks the flow of gas. While the footbed 510 of the perforated last 502 may be formed of a liquid impermeable material, the material may be breathable, and the perforations 508 provide a vent for the flow of gas. The gas may travel through the foamed material in cavity 504 and into perforations 508, as indicated by arrows 528, to equalize the pressure gradient between cavity 504 and inner conduit 514 of perforated last 502. Gas entering perforations 508 in toe region 503 of perforated last 502 may be directed into manifold 512 and then flow to internal conduit 514, while gas entering perforations 508 in heel region 505 of perforated last 502 may be evacuated directly into internal conduit 514. The gas may be pumped to the vacuum source 515, as indicated by arrows 530, thereby reducing the likelihood that large bubbles, air pockets, or voids remain enclosed within the midsole.

In another cross-section 900 of the third example of the perforated last 602, the perforated last 602 is similarly positioned over the mold 506. The perforated last 602 may have an external shape similar to the perforated last 502 of fig. 8. However, the perforated last 602 may be substantially hollow, with the perforated last 602 having an internal conduit 604, the internal conduit 604 having a larger volume than the internal conduit 514 of fig. 8, extending through the perforated last 602 such that the interior surface 606 of the perforated last 602 is spaced apart from the exterior surface 608 of the perforated last 602 by a relatively uniform thickness of the material of the perforated last 602. This thickness is the distance between interior surface 606 and exterior surface 608 of perforated last 602. In this example, the perforated last 602 is hollow and is configured as a shell.

The perforation 610 may extend through the thickness of the perforated last 602, be disposed in the footbed 612 and upper surface of the perforated last 602. The perforations 610 allow gases generated during the midsole forming process to vent from the cavity 504 of the mold 506 into the inner conduit 604 of the perforated last 602. Evacuation of air from the foamed material of the midsole may be further assisted by activating a vacuum source 515, which vacuum source 515 is coupled to an opening 614 of the internal conduit 604 at the top of the perforated last 602.

The gas in the midsole material contained in the cavity 504 may create pressure within the cavity 504 and may not flow through the side surface 524 of the mold 506 or the top surface 526 of the bottom piston 522, may be directed through the perforations 610, as indicated by arrows 616, and into the internal conduit 604 of the perforated last 602 to mitigate the pressure gradient. The pressure gradient between the cavity 504 of the mold 506 and the inner conduit 604 of the perforated last 602 may be exacerbated by activating a vacuum source to reduce the pressure of the inner conduit 604. The gas drawn into the inner conduit 604 of the perforated last 602 through the perforations 610 may flow to the vacuum source 515, as indicated by arrows 618.

A fourth example of a perforated last 1002 is shown in cross-section 1300 in fig. 13. The perforated last 1002 is shaped and positioned similarly to the perforated lasts 502 and 602 of fig. 8 and 9, respectively, with the perforated last 1002 positioned over the mold 506. However, the perforated last 1002 of fig. 10 may be substantially solid, e.g., without any hollow areas or internal chambers. The perforated last 1002 may include a last extension 1004 protruding upward from an upper region of the perforated last 1002. Last extension 1004 may be formed of metal or some other rigid material and may be secured to an upper region of perforated last 1002. In one example, a vacuum source, such as vacuum source 515 of fig. 5-6, may be coupled to last extension 1004.

The perforated last 1002 may include a first set of perforations, which are through holes 1006, extending from the upper surface 1008 of the perforated last 1002 to the bottom surface 1010 of the perforated last 1002. Air inside cavity 504 of mold 506 is fluidly coupled to air around perforated last 1002 outside cavity 504 via through holes 1006, as indicated by arrows 1005. Through-holes 1006 allow gases generated during formation of the midsole in mold cavity 504 to vent from cavity 504 to the surrounding atmosphere.

The perforated last 1002 may also be fitted with a second set of perforations, which are blind holes 1012, extending from the bottom surface 1010 up through a portion of the distance between the upper surface 1008 and the bottom surface 1010 of the perforated last 1002. Blind hole 1012 may be coupled to conduit 1014 extending through the material of perforated last 1002, which conduit 1014 fluidly couples blind hole 1012 to port 1016 in last extension 1004. The gases generated during formation of the midsole in cavity 504 of mold 506 may be vented to the surrounding atmosphere through blind hole 1012 (as indicated by arrow 1007) and conduit 1014. Removal of gas through blind holes 1012 may also be assisted by coupling a vacuum source to last extension 1004.

It will be appreciated that the positioning of the manifold, internal conduits and perforations shown in fig. 8, 9 and 13 are non-limiting examples of perforated lasts. Other configurations of the components of the perforating last may be varied in a number of ways, such as varying the alignment, size, shape, and number, without departing from the scope of the present disclosure.

Fig. 10 and 11 illustrate in detail an example of how a midsole may be irreversibly attached to a lower edge of an upper of a shoe. A first cross-sectional view 1000 of one example of a shoe 702 is shown in fig. 10, in which an upper region 706 of an insole 704 is connected to a bottom region 708 of the insole 704 using strobel stitching. The sockliner 704 may be an interior lining of an upper 710 of the footwear 702. The midsole 712 is disposed below the bottom region 708 of the sockliner 704, curving upward along the exterior surface of the upper 710 to match the contour of the lower edge 714 of the upper 710. The outsole 713 may be attached to a bottom surface of the midsole 712.

Insole 704 may be shaped similar to the interior cavity of footwear 702 and the shape of the perforated last. By disposing the sockliner 704 within the void of the footwear 702, the sockliner 704 may provide a comfortable interface between an upper region of the user's foot, such as the instep of the foot, and the footwear upper 710, and also couple the upper 710 to the midsole 712 of the footwear 702.

Insole 704 may be formed of a flexible, resilient knit material, such as polyester, that has sufficient porosity to allow air to flow through the material, but not sufficient porosity to allow high viscosity fluids to flow through. The upper region 706 of the insole 704 may be attached to the bottom region 708 by a continuous border of stitching, forming a seam. In one example, the seam may be a strobel seam including strobel stitching. The strobel seam may continue around the perimeter of the edge of the upper region 706 of the insole 704, forming a continuous border of strobel stitching. Strobel suture 716 is shown in fig. 10, and is illustrated in greater detail in enlarged view 718. The strobel stitch 716 may be a circular loop sewn by a strobel machine that joins the upper 710, the upper and bottom regions 706, 708 of the insole 704, to the intersection of the upper 710 of the shoe 702 and the upper and bottom regions 706, 708 of the insole 704. At strobel stitch 716, the bottom region 708 of the upper 710 and insole 704 may share contact at the edges, while the upper region 706 of the insole 704 may be stacked above the upper 710.

Each strobel stitch 716 of the strobel seam may be spaced apart from adjacent strobel stitches such that a gap exists between each strobel stitch 716 of the seam. During injection of the foamed material of the midsole 712, the foamed material, prior to curing, may have a sufficiently low viscosity to penetrate through the gaps between each strobel stitch 716 of the seam. However, the viscosity may be high enough to not penetrate through the material of bottom region 708 of insole 704. The penetration of the foamed material allows a quantity of the penetrated material 720 of the midsole 712 to be disposed over the bottom region 708 of the insole 704 and over the upper region 706 of the insole 704 proximate the strobel stitch 716. In some examples, the foamed material may also permeate through the material of upper 710 and sockliner 704 if the material has a sufficiently high porosity.

The foamed material permeates through the gaps of the strobel seam securing the midsole 712 to the upper 710 of the shoe 702. As the foamed material cures and hardens, the material of midsole 712 continuously extends through the interstices of the strobel seam, as well as through the apertures of the material of upper 710, thereby forming a plurality of ligaments between midsole 712 and permeable material 720. Thus, the midsole is securely held in place against the lower edge 714 of the upper 710 and the bottom region 708 of the sockliner 704 by anchoring the midsole 712 to the sockliner 704 and the upper 710 via ligaments of foamed material.

The midsole 712 may be formed in a mold, such as the mold 404 of fig. 5-7 and the mold 506 of fig. 8-9 and 13, that includes a single inlet port without additional ports or channels for exchange between air in the cavity of the mold and air surrounding the mold. In one example, referring to the first half 403 and the second half 405 of the mold 404 of fig. 5-7, the first half and the second half of the mold may not include any ports to vent gas or excess foamed material. The material of the midsole 712 is confined within the cavity while gas may pass through the gas permeable bottom region 708 of the insole 704. In contrast to conventional molds that include vent ports through which the foamed material may permeate, there is no longer a need to trim the cured midsole material that permeates through the vent ports. Thus, the amount of labor involved in the manufacturing process is reduced.

A second cross-sectional view 1100 of an example of a shoe 802 is shown in fig. 11, where a blind seam may be used to join an upper 810 of the shoe 802 to a footbed 808. Footbed 808 may be formed of a flexible material, such as nylon, that is porous so that air may flow through the material, but that is impermeable to viscous fluids. The blind seam may constrain bottom edge 806 of upper 810 to the edge of footbed 808 and continue around the perimeter of footbed 808. Midsole 812 is disposed below footbed 808 and may curve upward along the exterior surface of upper 810 to match the contour of lower portion 814 of upper 810. The outsole 813 may be attached to the bottom surface of the midsole 812.

The bottom edge 806 of the upper 810 and the edge of the footbed 808 may be stitched such that the bottom edge 806 of the upper 810 and the edge of the footbed 808 curve downward along the y-axis at the merge area and at an angle, extending away from the interior 817 of the shoe 802 and extending below the horizontal stitch line 818. The extension of the bottom edge 806 of the upper 810 and the edge of the footbed 808 away from the interior 817 of the shoe 802 may form a seam allowance 816.

The blind seam may include a plurality of horizontal stitches, represented in fig. 11 by a single horizontal stitch 818, and illustrated in greater detail in the enlarged view 820. Horizontal stitch 818 may be coaxial with the x-axis and may join bottom edge 806 of upper 810 to an edge of footbed 808 to form seam margin 816. Seam allowance 816 may terminate at a lower end having primary ends 822 and 824 of upper 810 and footbed 808, respectively.

The high density of horizontal stitches 818 and the horizontal stitches of the blind seam (e.g., small gaps therebetween), or in some examples, the overlapping horizontal stitches of the blind seam may block the penetration of the foamed material (used to form the midsole 812) through the blind seam. When the foam material cures, the material may irreversibly couple with the surfaces provided by the irregularly shaped virgin ends 822, 824 of the upper 810 and footbed 808 and to the surfaces of the seam allowance 816 and horizontal stitching 818. Thus, the midsole 812 is securely attached to the upper 810 of the shoe 802 by being cured and coupled to the seam allowance 816 that extends downward into the midsole 812.

The midsole of the shoe may be attached to the upper of the shoe by injecting the foamed material as shown in fig. 5-7, and allowing the foamed material to cure and attach (by infiltration through a strobel seam as shown in fig. 10, or by a seam allowance adhered to a blind seam as shown in fig. 11). While both of these methods may be similarly effective for securing the midsole to the upper, the use of blind seams may be more desirable with respect to aesthetic appearance. Penetration of the foamed material through strobel stitches of the strobel seam may appear as irregular patches of hardened material along the inner perimeter of the bottom region of the insole in the shoe. However, the blind seam retains the foamed material in the midsole, thereby giving the interior a cleaner appearance and a well-defined boundary between components of the footwear (e.g., between the upper and the footbed). Therefore, the blind seam method may be considered more desirable from a market perspective.

An example of a method 1200 for forming an article of footwear, such as a shoe, by an injection molding process is provided in fig. 12. Method 1200 includes using a perforated last, such as the perforated last of fig. 3-4, and using a mold having a cavity, such as mold 404 of fig. 5-7 or mold 506 of fig. 8-9 and 13. At 1202, the method includes preparing a component of a shoe. The preparing may include mounting the upper part of the shoe on a perforated last. The upper component may include a preformed upper and a footbed, or an upper with a seam footbed, or a single upper unit without a footbed or footbed. Preparing the component may also include inserting a perforated last into the footbed or the upper at 1204, where the upper wraps around an upper portion of the last. The upper may be tightened by adjusting the lacing system or by a velcro fastening system.

Preparing the shoe component can also include preparing a top surface of a preformed outsole by roughening and priming the surface at 1206. An adhesive, such as cement, can be applied to the upper surface of the outsole, and the outsole can be heated to activate the cement. Further, preparing the shoe component can include positioning the outsole at the bottom of the cavity of the mold at 1208 while a bottom piston of the mold, such as bottom piston 412 of fig. 5-7, is in a lowered position. The preparation of the shoe component also includes positioning a perforated last over the cavity of the mold at 1210 such that the cavity is a closed, sealed chamber.

At 1212, the method includes injecting a foamed material, such as polyurethane, through an inlet opening in a bottom half of the mold. The foamed material may fill a portion of the interior volume of the cavity. At 1214, the bottom piston is raised such that an outsole placed on the bottom piston is above the inlet opening in the bottom half of the mold, and air surrounding the mold is not fluidly coupled to air in the cavity through the inlet opening.

At 1216, the method includes evacuating gas generated during curing of the foamed material. The air may be evacuated by venting through the material of the bottom region of the insole (which is impermeable to the foamed material) and through the perforations of the perforated last. The perforation may be fluidly coupled to the inner conduit of the perforated last. The evacuated gas may be vented to the atmosphere via an internal conduit. The internal conduit may also be coupled to a vacuum source, such as a vacuum pump, to more effectively evacuate gas from the foamed material.

The evacuation of air from the foamed material of the midsole may be for a curing time of the foamed material, for example 5 to 8 minutes. When the foamed material hardens and cures, the material may permeate through the strobel stitches of the strobel seam and the material of the upper component, thereby joining the upper region of the sockliner to the bottom region of the sockliner and the upper, thereby securing the midsole to the upper. Alternatively, if a blind seam is present instead of a strobel seam, the foamed material may be irreversibly coupled to the seam margin of the blind seam of the upper and footbed, similarly attaching the midsole to the upper of the shoe. At 1218 of the method, the mold is opened by separating the top and bottom halves of the mold and the finished shoe is removed.

In this manner, the shoe may be manufactured by using a perforated last and forming a midsole by injection molding. The foamed material may be injected, open cast or cast into the mold, and the gases generated during curing of the foamed material may be evacuated through the perforations of the perforated last. The perforation may be fluidly coupled to an internal conduit of the perforated last, which may be coupled to a vacuum pump to assist in drawing air bubbles, air pockets, and voids from the bottom. Reducing the presence of air bubbles, air pockets, and voids in the midsole may improve the aesthetic qualities of the midsole. The effectiveness of the midsole in coupling to the shoe upper may be further enhanced by providing a surface of seam allowance for a blind seam that attaches the footbed to the upper for adhesion. Alternatively, the foamed material may permeate through the strobel stitched portion of the strobel seam of the insole and through the material of the upper to similarly attach the midsole to the upper of the shoe. The combination of the perforated last and the direct coupling of the midsole to the insole provides a simpler, faster manufacturing process than conventional methods and reduces the likelihood of forming an aesthetically degraded midsole, thereby reducing costs and improving production efficiency.

In one embodiment, a method comprises: positioning a perforated last relative to a cavity of a mold; and injecting a material configured to form a foam into the cavity to form a sole that is directly attached to the upper surrounding the perforated last. A first example of the method includes injecting a material into the cavity to form a midsole disposed between the upper and the outsole, and wherein the material is injected through an entry port of the mold that provides a single source of entry of the material into the cavity. A second example of the method optionally includes the first method, and further includes wherein forming the midsole includes: the material of the midsole is enclosed within continuous, air-impermeable surfaces of the mold that do not include openings other than the inlet ports, and the material of the midsole is enclosed within the surfaces of the cavity of the mold as the bottom piston of the mold is raised, while gas is allowed to flow from the midsole through the perforations of the perforated last to the internal conduits of the last that form openings at the top of the last. A third example of the method optionally includes one or more of the first and second methods, and further includes flowing gas through the perforations from the midsole to a manifold that fluidly couples the perforations to an internal conduit, and wherein the internal conduit is coupled to a vacuum source. A fourth example of the method optionally includes one or more of the first through third examples, and further includes mounting the upper of the article of footwear to a perforated last. A fifth example of the method optionally includes one or more of the first through fourth examples, and further comprising wherein mounting the upper onto a perforated last comprises: the perforated last is inserted into an upper attached to a seam footbed that is coupled to the upper by a blind seam extending around the perimeter of the footbed. A sixth example of the method optionally includes one or more of the first through fifth examples, and further comprising, wherein attaching the midsole to the upper comprises: the foamed material is cured around the seam allowance of the blind seam, which extends down into the midsole. A seventh example of the method optionally includes one or more of the first through sixth examples, and further comprising, wherein mounting the upper onto a perforated last comprises: an insole is positioned between the upper and the perforated last and covers a bottom surface of the perforated last with a bottom area of the insole, the insole being formed of a breathable material. An eighth example of the method optionally includes one or more of the first through seventh examples, and further comprising, wherein attaching the midsole to the upper comprises: the foamed material is joined with the bottom region of the insole such that the foamed material is in direct contact with a seam extending around a perimeter of the bottom region of the insole. A ninth example of the method optionally includes one or more of the first through eighth examples, and further comprising, wherein attaching the midsole to the upper comprises: allowing the foamed material to penetrate through the gaps between the strobel stitches forming the seams of the insole and through the pores of the material of the upper, into the interior of the article of footwear; and curing the foamed material, wherein a portion of the foamed material is disposed in an interior of the article of footwear and is coupled to the midsole through the gap via the extended portion of the foamed material.

In another embodiment, a system comprises: perforating a shoe tree; a mold having a cavity shaped to receive a bottom region of the perforated last; and an injection machine configured to be coupled to an inlet port in the mold and to inject a material configured to foam and form the sole. In a first example of the system, the perforated last has a plurality of perforations extending through a thickness of a wall of the perforated last that fluidly couple air inside an interior conduit of the perforated last to air outside the perforated last, and wherein the plurality of perforations are concentrated adjacent an area of the midsole where an increased sole thickness is desired. A second example of the system optionally includes the first example, and further comprising wherein the plurality of perforations extend from an upper surface of the perforated last to a bottom surface of the perforated last. A third example of the system optionally includes one or more of the first and second examples, and further comprising wherein the plurality of perforations extend a portion of a distance between the upper surface and the bottom surface of the perforated last, and wherein the plurality of perforations are fluidly coupled to air surrounding the perforated last through the plurality of internal passages of the perforated last when the perforated last is positioned in the cavity of the mold. A fourth example of the system optionally includes one or more of the first through third examples, and further comprising wherein the inner conduit of the perforated last is adapted to be coupled to a vacuum source, and the inner conduit extends through an interior of the perforated last to an opening at a top of the perforated last, and wherein the inner conduit is a channel for drawing gas from the foamed material of the sole, wherein the inner conduit is positioned between the perforations of the perforated last and the vacuum source. A fifth example of the system optionally includes one or more of the first through fourth examples, and further includes wherein the seam formed by strobel stitches spaced apart from each other connects the upper of the shoe to the sockliner, and wherein a portion of the foamed material is disposed inside the shoe along the seam of the strobel stitches and is coupled to the sole by ligaments of the foamed material extending through gaps between the strobel stitches. A sixth example of the system optionally includes one or more of the first through fifth examples, and further comprising wherein the blind seam connects the upper of the shoe to the footbed of the shoe with a seam allowance extending downward into the sole, and wherein the sole is bonded to the seam allowance and the foamed material of the sole is retained within the sole below the seam footbed.

In another embodiment, a sole for a shoe comprises: a foamed material; a seam positioned over and in direct contact with the foamed material, the foamed material curing around and forming a mechanical coupling with the seam without the use of an adhesive; and a surface that is impermeable to the foamed material and in coplanar contact with an upper surface of the foamed material, wherein the midsole is free of large bubbles, air pockets, and voids. In a first example of a sole, the foamed material is polyurethane. The second example of the sole optionally includes the first example, and further includes wherein connecting the foamed material with the perforated last during forming of the sole vents gas generated during curing of the foamed material.

The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. These claims may refer to "an" element or "a first" element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.