Patent Publication Number: US-11019885-B2

Title: Manufacturing systems and processes for constructing articles of footwear using sacrificial straps

Description:
CLAIM OF PRIORITY AND CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of and priority to U.S. Provisional Patent Application No. 62/676,572, which was filed on May 25, 2018, and is incorporated herein by reference in its entirety and for all purposes. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to methods for manufacturing articles of footwear. More specifically, aspects of this disclosure relate to mechanical features for retaining segments of an article of footwear on a last during assembly of the footwear. 
     BACKGROUND 
     Articles of footwear, such as shoes, boots, slippers, sandals, and the like, are generally composed of two primary elements: an upper for securing the footwear to a user&#39;s foot; and a sole for providing subjacent support to the foot. Uppers may be fabricated from a variety of materials, including textiles, foams, polymers, natural and synthetic leathers, etc., that are stitched or bonded together to form a shell or harness for securely receiving a foot. For sandals and slippers, the upper may have an open toe or open heel construction, or may be generally limited to a series of straps extending over the instep and, in some designs, around the user&#39;s ankle. Conversely, boot and shoe applications typically employ a full upper with a closed toe and heel construction that encases the foot. An ankle opening through a rear quarter portion of the upper provides access to the footwear&#39;s interior, facilitating entry and removal of the foot into and from the upper. A lace or strap may be utilized to secure the foot within the upper. 
     A sole structure is generally attached to the underside of the upper, positioned between the user&#39;s foot and the ground. In many articles of footwear, including athletic shoes and boots, the sole structure is a layered construction that generally incorporates a comfort-enhancing insole, an impact-mitigating midsole, and a surface-contacting outsole. The insole, which may be located partially or entirely within the upper, is a thin and compressible member that provides a contact surface for the underside “plantar” region of the user&#39;s foot. By comparison, the midsole is mounted underneath the insole, forming a middle layer of the sole structure. In addition to attenuating ground reaction forces, the midsole may help to control foot motion and impart enhanced stability. Secured to the underside of the midsole is an outsole that forms the ground-contacting portion of the footwear. The outsole is usually fashioned from a durable, wearproof material that includes tread patterns engineered to improve traction. 
     Available techniques for fabricating an article of footwear may begin with interconnecting the individual pieces of material that form a forward “vamp” portion of the footwear&#39;s upper. An optional inner liner may then be joined to the interior surfaces of one or more exterior panels of the vamp. For designs where the vamp is formed separate from the toe box, a matching toe cap is stitched or bonded to the foreword end of the vamp. This pre-constructed assembly is then seated on a complementary fixture—more commonly known as a “last”—that has the general shape of a human foot. Historically, a pin, clip, shim, or spring-biased tang is used to temporarily fasten the assembly to the last. An assortment of processes may then be utilized to tighten the upper around the last, thereby imparting the foot-shaped contour of the last to the interior of the upper. In order to conform the upper of an athletic shoe around a last, for example, a strobel material may be secured to a lower perimeter of the upper and stretched across an area of the last corresponding to the plantar surface of the foot. A heel counter is affixed to a rearward end of the vamp, and the sole structure is secured to the underside of the upper to generally enclose the strobel between the upper and sole structure. 
     SUMMARY 
     Presented herein are methods for constructing articles of footwear using sacrificial straps to secure segments of the footwear to a manufacturing fixture, shoe structure segments prefabricated with such sacrificial straps, systems for manufacturing articles of footwear using sacrificial straps, and methods for operating such systems. By way of example, there is presented a manufacturing process workflow for fabricating an athletic shoe using a sacrificial heel strap to temporarily secure the forward vamp and attached strobel to a last. Upon completing the manufacturing procedure or procedures associated with the last, such as attachment of the heel counter and sole structure to the vamp, the sacrificial heel strap is permanently removed. In this example, the sacrificial heel strap may generally consist of a thin, elongated strip of material that is removably attached at opposing ends thereof proximal the welt line of the vamp. This sacrificial heel strap may be formed from a material that is different from and structurally inferior to that of the other segments of the shoe. The material may be frangible, easily cut, or fabricated with features to facilitate removal of the strap, such as a tear seam or micro-slots. In addition, the heel strap may be configured to fit inside the upper, e.g., adjacent a heel cap/rear quarter of the shoe structure, yet be readily accessible for ease of removal of the strap once the shoe is pulled from the last. 
     Aspects of this disclosure are directed to manufacturing processes for constructing footwear. In an example, a method is presented for manufacturing an article of footwear for a foot of a user. This representative method includes, in any order and in any combination with any of the above or below disclosed features and options: providing a first segment of an upper, wherein the upper is configured to attach to the user&#39;s foot and includes a sacrificial strap that is attached at opposing ends thereof to the first segment; placing the first segment of the upper on a manufacturing fixture; attaching the first segment to the manufacturing fixture by positioning the sacrificial strap against the manufacturing fixture; attaching a second segment of the upper to the first segment; removing the first and second segments from the fixture; and disconnecting the sacrificial strap from the upper. 
     In another example, a method is presented for assembling an athletic shoe. This representative method includes, in any order and in any combination with any of the above or below disclosed features and options: providing a foot-shaped last with a forefoot region, a heel region, and a midfoot region interposed between and adjoining the heel and forefoot regions; placing a vamp segment of the athletic shoe&#39;s upper, e.g., with an attached strobel, on at least the forefoot region of the last, the upper including a sacrificial strap that is removably attached at opposing ends thereof proximate a rear edge of the vamp; temporarily attaching the vamp to the last by positioning the sacrificial strap around and against at least the heel region of the last; attaching a heel counter to the vamp, e.g., via stitching, bonding, or other suitable means; attaching a sole structure of the athletic shoe to the vamp and heel counter, e.g., via welting, foxing, or other suitable means; after attaching the heel counter and sole structure to the vamp, removing the vamp, heel counter and sole structure from the last; and, after removing the assembled athletic shoe from the last, tearing or cutting the sacrificial strap from the upper. 
     Further aspects of the disclosure are directed to pre-assembled segments of an article of footwear with sacrificial straps. For instance, an article of footwear includes an upper that receives and attaches to a foot of a user. The upper is fabricated with a vamp, a heel counter that rigidly attaches to the vamp, and a sacrificial strap that nests inside the heel counter and removably attaches at opposing ends thereof proximate a rear edge of the vamp. The article of footwear also includes a sole structure that attaches to a lower portion of the upper and supports thereon the user&#39;s foot. The sole structure includes an outsole that defines the ground-engaging portion of the footwear. After assembling the footwear, the sacrificial strap is configured to be permanently disconnected from upper. 
     Other aspects of the present disclosure are directed to manufacturing systems for constructing an article of footwear. In an example, a footwear manufacturing system includes a flat machine that constructs a first segment of an upper with a sacrificial strap that is attached at opposing ends thereof to the first segment. The manufacturing system also includes a last with a foot-shaped section that seats thereon the various segments of the upper. One or more of these segments may be mechanically attached to the last by positioning the sacrificial strap against the last. After being securely attached to the last, the segments of the upper are rigidly attached to each other. A finishing bench receives the attached segments of the upper such that the sacrificial strap can be permanently removed from the upper. 
     For any of the disclosed systems, methods, and devices, disconnecting the sacrificial strap from the upper may include cutting the sacrificial strap off of the first segment. To facilitate removal, the sacrificial strap may be fabricated from a polymeric material and/or textile material, both of which are configured to be readily cut, e.g., by a pair of manually operated scissors. Optionally, the sacrificial strap may be fabricated with a reduced-thickness section and/or a slotted section, both of which facilitate cutting the strap. Alternatively, disconnecting the sacrificial strap from the upper may include tearing the sacrificial strap off of the first segment. To facilitate removal by tearing, the sacrificial strap may be fabricated from a frangible material that is configured to be readily torn. Optionally, the sacrificial strap may be fabricated with a tear seam that includes a series of apertures and/or micro-slots that facilitate tearing of the strap. 
     For any of the disclosed systems, methods, and devices, the first segment may be fabricated with a first material while the sacrificial strap is fabricated with a second material that is distinct from the first material of the first segment. As another option, the sacrificial strap may consist essentially of an elongated, single-piece sling that is bonded or stitched to the first segment. In other words, the sacrificial strap may be characterized by a lack of a buckle, buckle through holes, surface finishing, interior lining, and other features characteristic of permanent straps used for sandals, high-heeled shoes, etc. As indicated above, the first segment of the upper to which the sacrificial strap is attached may be a vamp segment of the upper; however, it is envisioned that sacrificial straps may be attached to other segments of the shoe structure to facilitate assembly of the footwear. For instance, the first and second segments discussed above may include a vamp segment, a strobel segment attached to the vamp segment, and/or a heel counter segment. 
     The above summary is not intended to represent every embodiment or every aspect of the present disclosure. Rather, the foregoing summary merely provides an exemplification of some of the novel concepts and features set forth herein. The above features and advantages, and other features and attendant advantages of this disclosure, will be readily apparent from the following detailed description of illustrated examples and representative modes for carrying out the present disclosure when taken in connection with the accompanying drawings and the appended claims. Moreover, this disclosure expressly includes any and all combinations and subcombinations of the elements and features presented above and below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A and 1B  are workflow diagrams schematically illustrating a representative system and process for manufacturing an article of footwear using a sacrificial strap in accordance with aspects of the present disclosure. 
     
    
    
     The present disclosure is amenable to various modifications and alternative forms, and some representative embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the novel aspects of this disclosure are not limited to the particular forms illustrated in the above-enumerated drawing. Rather, the disclosure is to cover all modifications, equivalents, combinations, subcombinations, permutations, groupings, and alternatives falling within the scope of this disclosure as encompassed by the appended claims. 
     DETAILED DESCRIPTION 
     This disclosure is susceptible of embodiment in many different forms. There are shown in the drawings and will herein be described in detail representative embodiments of the disclosure with the understanding that these illustrated examples are provided as an exemplification of the disclosed principles, not limitations of the broad aspects of the disclosure. To that extent, elements and limitations that are described, for example, in the Abstract, Technical Field, Background, Summary, and Detailed Description sections, but not explicitly set forth in the claims, should not be incorporated into the claims, singly or collectively, by implication, inference or otherwise. 
     For purposes of the present detailed description, unless specifically disclaimed: the singular includes the plural and vice versa; the words “and” and “or” shall be both conjunctive and disjunctive; the words “any” and “all” shall both mean “any and all”; and the words “including” and “comprising” and “having” shall each mean “including without limitation.” Moreover, words of approximation, such as “about,” “almost,” “substantially,” “generally,” “approximately,” and the like, may be used herein in the sense of “at, near, or nearly at,” or “within 0-5% of,” or “within acceptable manufacturing tolerances,” or any logical combination thereof, for example. Lastly, directional adjectives and adverbs, such as fore, aft, medial, lateral, proximal, distal, vertical, horizontal, front, back, left, right, etc., may be with respect to an article of footwear when worn on a user&#39;s foot and operatively oriented with the base of the sole structure seated on a flat surface, for example. 
     Referring now to the drawings, wherein like reference numbers refer to like features throughout the several views,  FIGS. 1A and 1B  illustrate a representative manufacturing system and attendant manufacturing process, collectively designated at  10  in the Figures, for constructing an article of footwear, which is designated generally at  12  in  FIG. 1B  and portrayed herein for purposes of discussion as an athletic shoe or “sneaker.” The illustrated footwear  12 —also referred to herein as “shoe” for brevity—is merely an exemplary application with which novel aspects and features of this disclosure may be practiced. In the same vein, implementation of the present concepts into the illustrated manufacturing system architecture should be appreciated as a representative application of the disclosed concepts. It should therefore be understood that aspects and features of this disclosure may be incorporated into other manufacturing systems and processes, and may be implemented to construct any logically relevant type of footwear. As used herein, the terms “shoe” and “footwear,” including permutations thereof, may be used interchangeably and synonymously to reference any relevant type of garment worn on a human foot. Lastly, the features presented in the drawings are not necessarily to scale and are provided purely for instructional purposes. Thus, the specific and relative dimensions shown in the drawings are not to be construed as limiting. 
     The representative article of footwear  12  is depicted in  FIGS. 1A and 1B  as a bipartite construction that is generally composed of a foot-receiving upper  14  mounted on top of a subjacent sole structure  16 . For ease of reference, footwear  12  may be divided into three anatomical regions: a forefoot region R FF , a midfoot region R MF , and a hindfoot (heel) region R HF , as shown in  FIG. 1B . Footwear  12  may also be divided into a lateral side, which is portrayed at the bottom of  FIG. 1B , and a medial side (not visible in the views provided) opposite the lateral side. In accordance with recognized anatomical classifications, the forefoot region R FF  is located at the front of the footwear  12  and generally corresponds with the phalanges (toes), metatarsals, and any interconnecting joints. Interposed between the forefoot and hindfoot regions R FF  and R HF  is the midfoot region R MF , which generally corresponds with the cuneiform, navicular and cuboid bones (i.e., the arch area of the foot). Heel region R HF , in contrast, is located at the rear of the footwear  12  and generally corresponds with the talus and calcaneus bone. Both lateral and medial sides of the footwear  12  extend through all three anatomical regions R FF , R MF , R HF , and each corresponds with a respective lateral segment of the footwear  12 . While only a single shoe  12  for a right foot of a user is shown in the drawings, a mirrored, substantially identical counterpart for a left foot of a user may be produced in accordance with the disclosed techniques. Recognizably, the shape, size, material composition, and method of manufacture of the shoe  12  may be varied, singly or collectively, to accommodate any conventional and nonconventional applications. 
     With continuing reference to  FIG. 1B , the upper  14  is depicted as having a closed heel and toe configuration that is generally defined by a forward vamp  18  and a rearward heel counter  20 . According to the illustrated example, the vamp  18  segment of the upper  14  is located in the forefoot and midfoot regions R FF  and R MF  of the footwear  12 , and includes an integral toe box  22 . With this design, the vamp  18  of  FIGS. 1A and 1B  effectively defines the front and center parts of the shoe&#39;s upper  14 , covering and protecting the foot from the toes to the ankle. Heel counter  20  is located aft of the vamp  18  and includes the rear and rear sides of the upper  14  that cover the foot from the ankle to the heel. Closing off the undersides of the vamp  18  and heel counter  20  is a strobel  24  sheet material that is sewn or otherwise affixed to the lower perimeter of the upper  14 , e.g., to facilitate lasting and other fabrication processes. While portrayed in the drawings as comprising three primary segments, namely the vamp  18 , heel counter  20 , and strobel  24 , the upper  14  may be fabricated as a single-piece construction or may be composed of any number of segments, including a toe cap, heel cap, ankle cuff, interior liner, etc. 
     The upper  14  portion of the footwear  12  may be fabricated from any one or combination of a variety of materials, such as textiles, engineered foams, polymers, natural and synthetic leathers, etc. Individual segments of the upper  14 , once cut to shape and size, are stitched, adhesively bonded, welded, or otherwise joined together to form an interior void for comfortably receiving a foot. The individual material elements of the upper  14  may be selected and located with respect to the footwear  12  in order to impart properties of durability, air-permeability, wear-resistance, flexibility, and comfort, for example. An ankle opening  11  ( FIG. 1B ) in the rear quarter of the upper  14  provides access to the interior of the assembled shoe  12 . A shoelace  26 , strap, buckle, or other conventional mechanism may be utilized to modify the girth of the upper  14  to more securely retain the foot within the interior of the shoe  12  as well as to facilitate entry and removal of the foot into and from the upper  14 . Lace  26  may be threaded through a series of eyelets in the upper  14 ; a tongue  28  may extend between the lace  26  and the interior void of the upper  14 . 
     Sole structure  16  is rigidly secured to the upper  14  such that the sole structure  16  extends between the upper  14  and a support surface upon which a user stands, for example. In effect, the sole structure  16  functions as an intermediate support platform that separates the user&#39;s foot from the ground. In addition to attenuating ground reaction forces and providing cushioning for the foot, sole structure  16  of  FIG. 1  may provide traction, impart stability, and help to limit various foot motions, such as inadvertent foot inversion and eversion. While portrayed in the drawings as a multi-layered “sandwich” assembly, the shoe&#39;s sole structure  16  may be fabricated as a single-piece construction or may be composed of any number of additional segments. 
     In accordance with the illustrated example, the sole structure  16  is fabricated as a sandwich structure with a top-most insole  30 , an intermediate midsole  32 , and a bottom-most outsole  34 . Insole  30  is shown located partially within the interior void of the footwear  12 , firmly secured to a lower portion of the upper  14 , such that the insole  30  is located adjacent a plantar surface of the foot. Underneath the insole  30  is a midsole  32  that incorporates one or more materials or embedded elements that enhance the comfort, performance, and/or ground-reaction-force attenuation properties of footwear  12 . These elements and materials may include, individually or in any combination, a polymer foam material, such as polyurethane or ethylene-vinyl acetate (EVA), filler materials, moderators, air-filled bladders, plates, lasting elements, or motion control members. Outsole  34 , which may be absent in some configurations of footwear  12 , is secured to a lower surface of the midsole  32 . The outsole  34  may be formed from a rubber material that provides a durable and wear-resistant surface for engaging the ground. In addition, outsole  34  may also be textured to enhance the traction (i.e., friction) properties between footwear  12  and the underlying support surface. 
     A variety of techniques, elective processes, and system architectures may be utilized to manufacture the athletic shoe  12 . An example of a footwear manufacturing system  10  and attendant workflow process that incorporates the use of one or more sacrificial straps  40  to fabricate an article of footwear  12  are set forth in  FIGS. 1A and 1B . Only select components of the manufacturing system  10  have been shown by way of example in the drawings and will be described in detail hereinbelow. Nevertheless, the manufacturing system  10  of  FIGS. 1A and 1B  can include numerous additional and alternative fabrication procedures, as well as other available work cells and equipment, without departing from the intended scope of this disclosure. It should also be recognized that the order of execution of the illustrated operations may be changed, additional operations may be added, and some of the operations described may be modified, combined, or eliminated. 
     Initial stages of the manufacturing process may comprise supplying, accessing, and/or utilizing (collectively “providing”) the various materials, tools and machines needed to manufacture the athletic shoe  12 . By way of non-limiting example, the representative footwear manufacturing system  10  of  FIG. 1A  employs a flat machine  42  at step S 1  for cutting discrete segments of the upper  14  and, for some system architectures, closing sections of the upper  14  via sewing or other suitable joining technique. At step S 2 , a molding machine  44  forms a single-layer sole or a multi-layered sole structure  14  through an apposite methodology, such as injection, compression, or vacuum molding, extrusion and cutting, stamping, etc. Step S 3  utilizes a manufacturing fixture, portrayed in the drawings as a shoe last  46 , to provide a working mold surface for shaping the upper  14  and joining the various shoe structure segments to provide an assembled, substantially finished shoe  12 . Each of the aforementioned operations may be automated, e.g., through a central system controller or distributed network of machine controllers, or may be carried out manually, e.g., through conventional methods of clicking, cutting, sewing, surface treating, hand lasting, foxing, welting, etc. 
     Shoe last  46  of  FIG. 1A  takes on the general shape of a human foot as well as portions of the adjoining ankle. Although depicted as having a solid, one-piece construction, last  46  may also be hollow, may be formed from multiple interconnected elements, and may comprise movable features that vary the overall shape and size of the lasting surface. In the same vein, the shape, size and/or material composition of the last  46  may be modified from those shown in the drawings to accommodate different shoe sizes, types, or other intended application. Flat machine  42  of  FIG. 1A  produces multiple segments of the upper  14 , including the forward vamp  18  (representative of a “first segment”) and the rearward heel counter  20  (representative of a “second segment”), for assembly on the last  46 . An impermanent strap or sling may be incorporated into one or more of all of the shoe structure segments to temporarily secure those segments to the last  46  during assembly of the shoe  12 . According to the illustrated example, opposing longitudinal ends of a sacrificial heel strap  40  are attached proximate respective rear edges of the vamp  14 . Sacrificial strap  40  of  FIGS. 1A and 1B  is limited to an elongated and flexible single-piece strip of material that is bonded or stitched to the vamp  14  just above the welt line. It is envisioned, however, that the sacrificial strap  40  may comprise multiple interconnected pieces and, optionally, may originate or terminate at other locations on the vamp  14 . To reduce material costs without undermining the functional integrity of the sacrificial heel strap  40 , the strap  40  may be formed from a durable and elastic material that is less expensive, structurally inferior to, and less aesthetically appealing than the materials used to form the other segments of the upper  14 . 
     During assembly of the athletic shoe  12 , the vamp  18  segment of the upper  14  is loosely placed on a complementary forward section of the last  46  (e.g., that section associated with the forefoot and midfoot regions R FF  and R MF  and extending over the extensor hallucis and extensor digitorum ligaments of the foot), as indicated at step S 4 . Strobel  24  is concomitantly stretched across the underside surface of the last  46 , which may generally correspond to the plantar surface of the foot, as seen in  FIG. 1A . Prior to placing the heel counter  20  segment of the upper  14  on the last  46 , the vamp  18  and strobel  24  are temporarily secured in place by pulling the sacrificial strap  40  aft towards the rear of the last  46 , and positioning the sacrificial strap  40  around and against the Achilles tendon section of the last  46 . In so doing, the vamp  18  and strobel  24  are securely retained in place without the need for adhesives or two-sided tape or a pin, clip, shim, or other mechanical device. After securely attaching the vamp  18  and strobel  24  to the last  46 , the heel counter  20  is placed on a complementary rearward section of the last  46  (e.g., that section associated with the hindfoot region R HF  and extending around the calcaneus bone and Achilles tendon), as indicated at step S 5 . At this time, heel counter  20  is rigidly attached to the vamp  18  and strobel  24  by any suitable means available. The sole structure  16  is secured to both the vamp  18  and heel counter  20  segments of the upper  14 . Once the upper  14  is assembled, mounted on the sole structure  16 , and lasted on the last  46 , the shoe  12  is removed from the last, as indicated at step S 6 . 
     Turning next to  FIG. 1B , the sacrificial strap  40  may be permanently detached from the shoe  12  upon completion of the assorted manufacturing processes associated with the last  46  and upon removal of the shoe  12  from the last  46 . In accord with the illustrated example, step S 7  of  FIG. 1B  may include securing the unfinished shoe  12  to a work bench or transfer fixture (collectively designated  48 ). The sacrificial heel strap  40  is then severed from the upper  14  by cutting the longitudinal ends of the strap  40  off of the vamp  18 , as indicated at step S 8 . To facilitate this operation, the sacrificial strap  40  may be fabricated from a polymeric material (e.g., low-density polyethylene) and/or a textile material (e.g., nonwoven cotton) that is constructed to be manually cut with a pair of scissors  50 . As another option, the sacrificial strap  40  may be fabricated with a reduced-thickness section  52  and/or a slotted section  54  that is designed to be readily cut. Alternatively, disconnecting the sacrificial heel strap  40  from the upper  14  may merely involve tearing the longitudinal ends of the strap  40  from the aft end of the vamp  18 . To facilitate this operation, the sacrificial strap  40  may be fabricated from a frangible material (e.g., loose-knit, low-thread-count cotton) that is easy to tear by hand. As another option, the sacrificial strap  40  may be fabricated with a tear seam  56  with a series of apertures and/or micro-slots configured to be readily torn. The severed strap  40 A is thereafter discarded, recycled, or reused for fabricating another article of footwear. 
     Aspects of the present disclosure have been described in detail with reference to the illustrated embodiments; those skilled in the art will recognize, however, that many modifications may be made thereto without departing from the scope of the present disclosure. The present disclosure is not limited to the precise construction and compositions disclosed herein; any and all modifications, changes, and variations apparent from the foregoing descriptions are within the scope of the disclosure as defined by the appended claims. Moreover, the present concepts expressly include any and all combinations and subcombinations of the preceding elements and features.