BACKGROUND

[0001 ] Footwear tends to be mass produced with variance among a specific style or type of footwear typically being limited to size. Mass production of footwear is facilitated by industrial processes, such as injection molding, that are effective in keeping costs down when many of the same item are made.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] FIG. 1 is a perspective view of an example apparatus to injection mold a midsole of an article of footwear including adhesion surface situated between a sequence of adjacent materials positioned along the length of the midsole.

[0003] FIG. 2A is a cross-sectional view of the example apparatus of FIG. 1 with first and second inserts present in a midsole mold cavity.

[0004] FIG. 2B is a cross-sectional view of the example apparatus of FIG. 1 after injection of a first material.

[0005] FIG. 2C is a cross-sectional view of the example apparatus of FIG. 1 after removal of the first insert from the mold cavity.

[0006] FIG. 2D is a cross-sectional view of the example apparatus of FIG. 1 after injection of a second material.

[0007] FIG. 2E is a cross-sectional view of the example apparatus of FIG. 1 after removal of the second insert from the mold cavity. [0008] FIG. 2F is a cross-sectional view of the example apparatus of FIG. 1 after injection of a third material.

[0009] FIG. 2G is a cross-sectional view of the example apparatus of FIG. 1 after completion of the midsole having a sequence of adjacent materials positioned along its length.

[0010] FIG. 3A is a top perspective view of an example insert including a tongue to define an adhesion surface between injected materials.

[0011] FIG. 3B is a bottom perspective view of the example insert of FIG. 3A.

[0012] FIG. 4 is a bottom perspective view of an example insert including a protrusion in the vicinity of a tongue of the example insert to increase adhesion between injected materials.

[0013] FIG. 5 is a bottom perspective view of an example insert including an open channel to convey injected material to a volume in the vicinity of a tongue of the example insert

[0014] FIG. 6 is a bottom perspective view of an example inserts, where one insert is to be replaced by another insert during an injection molding process.

[0015] FIG. 7A is a side schematic view of an example tongue geometry for a sequence of inserts.

[0016] FIG. 7B is a side schematic view of example concave tongue geometry for a sequence of inserts.

[0017] FIG. 7C is a side schematic view of example planar tongue geometry for a sequence of inserts.

[0018] FIG. 7D is a side schematic view of example differing tongue geometry for a sequence of inserts.

[0019] FIG. 8 is a flowchart of an example method of molding a midsole of an article of footwear with a tongue of material to bond to another material. [0020] FIG. 9 is a flowchart of an example method of using inserts to progressively mold a midsole of an article of footwear specific to a wearer.

DETAILED DESCRIPTION

[0021 ] Footwear often lacks customizable features or features specific to a single wearer or small group of wearers. The mass production technologies that keep costs low also tend to inhibit wearer-specific features.

[0022] When molding an article of footwear, such as a shoe, a midsole may be customized by the sequenced use of inserts in the mold. An insert blocks the filling of injected material at the volume of the insert. That is, the insert acts as a dummy that creates a temporary void of material in the midsole. The unfilled volume may be filled by subsequently injected material after removal of the insert. The insert may define a tongue that increases adhesion surface area between adjacent injected materials. Any number of inserts may be used to provide a sequence of different midsole materials along the length of the article of footwear. The midsole may thus have a characteristic, such as material composition, density, color, stiffness, etc., that varies by length. The article of footwear may thereby be tailored to the wants or needs of the wearer.

[0023] FIG. 1 shows an example apparatus 100 to injection mold a midsole of an article of footwear, such as a shoe, including an adhesion surface situated between a sequence of adjacent materials positioned along the length of the midsole. The apparatus 100 may be used with an injection molding machine, such as a carousel-type machine that rotates a plurality of molds to different stations. The example apparatus 100 may be a mold or part of mold of such an injection molding machine. The apparatus includes a mold frame 102, a first insert 104, and a second insert 106.

[0024] The mold frame 102 defines a mold cavity 108. The mold frame 102 may include opposing side frames 110, 112 and a bottom frame 114. The mold frame 102 receives a last 1 16 that carries an upper 118 of an article of footwear that is under manufacture to enable the molding of a midsole onto the upper 118. The side frames 1 10, 112, bottom frame 114, and the last 116 may be movable with respect to each other to open and close the mold cavity 108. The opposing side frames 110, 1 12, bottom frame 114, and upper 118 as carried by the last 1 16 may be brought into mutual engagement to dose the cavity 108. Material, such as polyurethane (PU), thermoplastic polyurethane (TPU), rubber, or the like, may be injected into the dosed mold cavity 108 to form a midsole that is directly attached to the upper 118.

[0025] The first insert 104 is insertable into the mold cavity 108 to define a first midsole volume 120 within the mold cavity 108. The first midsole volume 120 may be injected with a first material.

[0026] The second insert 106 is insertable into the mold cavity 108 to define a second midsole volume within the mold cavity 108. The second midsole volume may be a volume that is filled after the first material has been injected into the first midsole volume 120, after the first insert 104 has been removed from the mold cavity 108, and when the second insert 106 is present in the mold cavity 108. That is, the second midsole volume may be the volume occupied by the first insert 104. The second midsole volume may be injected with a second material that has a characteristic (e.g., material composition, density, color, stiffness, etc.) different from the first material.

[0027] In some examples, the first and second inserts 104, 106 may be shaped to be inserted into the mold cavity 108 at the same time to define the first midsole volume 120. After injection of the first material into the first midsole volume 120, the first insert 104 may be removed to open the second midsole volume. After injection of the second material into the volume formerly occupied by the first insert 104, the second insert 106 may be removed to open a third midsole volume to receive injection of a third material.

[0028] In other examples, the first and second inserts 104, 106 are mutually exclusive. The first insert may be present in the mold cavity 108 and the second insert may be removed from the mold cavity 108, so as to define the first midsole volume 120. Then, the first insert 104 may be removed and the second insert may be inserted into the mold cavity 108 to define the second midsole volume. The differential volume between the first and second inserts 104, 106 may thereby define the second midsole volume.

[0029] The first and second inserts 104, 106 may be used to create three midsole volumes to allow the injection of three materials of different

characteristics to form the midsole. Any suitable quantity and shape of inserts may be used to position different midsole volumes at a sequence of adjacent positions along a length 122 of the last 1 16. Thus, a sequence of materials of different characteristics may be injected to make a midsole of specific characteristic. A characteristic, such as material composition, density, color, stiffness, and similar, may be varied along the length of the midsole. This may be used to create a unique appearance, density profile, or similar feature for the article of footwear. It is contemplated that, in many examples, between three to eight inserts may provide a like number of zones of different midsole materials that would provide sufficient resolution in a material characteristic being varied. Any number of material characteristics may be varied along the length of a given midsole.

[0030] The first insert 104 includes a first tongue 124 that shapes the first midsole volume 120 to promote adhesion of material injected into the first midsole volume 120 to subsequently injected material and/or to the upper 118. The tongue 124 may be shaped to increase contact between injected midsole materials and/or the upper 118. The tongue 124 may reduce the risk of detachment of different midsole materials and premature mechanical failure of the midsole.

[0031 ] FIGs. 2A-2G show an example method of manufacture of a midsole of an article of footwear with a progressive definition of the midsole as an arrangement of inserts in a mold cavity is changed. The method may be performed by the example apparatus 100 of FIG. 1 and is described in terms of the apparatus 100 for sake of convenience. Further detail of the apparatus 100 is shown. The method may be performed by other apparatuses. [0032] FIG. 2A shows first and second inserts 104, 106 inserted into a mold frame that is closed around a lasted upper 118. The first and second inserts 104, 106 do not completely fill the mold cavity and thereby define an empty first midsole volume 120.

[0033] The first insert 104 includes a first tongue 124 that extends lengthwise along the last 1 16 to provide a first adhesion surface 200 between first and second midsole volumes. The first adhesion surface 200 provides for adherence of a first material injected into the first midsole volume 120 to a second material injected into the second midsole volume (/.e., the space occupied by the first insert 104).

[0034] The first tongue 124 may be adjacent the upper 118 to provide an upper adhesion surface 202 between the second midsole volume (/ ^' .e., the space occupied by the first insert 104) and the upper 118 to adhere the second material injected into the second midsole volume to the upper 1 18.

[0035] The second insert 106 may include a second tongue 204 that extends lengthwise along the last 116 to provide a second adhesion surface 206 between the second midsole volume (/.e., the space occupied by the first insert 104) and a third midsole volume (/.e., the space occupied by the second insert 106) to adhere the second material injected into the second midsole volume to a third material injected into the third midsole volume.

[0036] As such, the inserts 104, 106 define a sequence of midsole volumes arranged along length 122 of the last 116. A midsole volume may be positioned to provide direct attachment of injected material to the upper 118. Further, a midsole volume may be partially defined by an insert tongue 124, 204, so that adjacent midsole volumes are provided with a large bonding surface.

[0037] A sprue channel 208 may be provided in a side frame 110 of the mold frame to deliver molding material to the mold cavity. Material may be injected at a heel. The first insert 104 may include a first material delivery channel 210 to provide a first material to the first midsole volume 120. The first material delivery channel 210 may be a through-channel that extends through the body of the first insert 104. The second insert 106 may include a second material delivery channel 212 to provide a second material to the second midsole volume ( i.e ., the space occupied by the first insert 104). The second material delivery channel 212 may be a through-channel that extends through the body of the second insert 106. The first and second material delivery channels 210, 212 may be positioned so that the channels 210, 212 are in communication when the first and second inserts 104, 106 are present together in the mold cavity. The sprue channel 208 may feed the second material delivery channel 212, which in turn may feed the first material delivery channel 210.

[0038] As shown in FIG. 2B, a first material may be injected through the sprue channel 208 and the channels 212, 210 of the inserts 106, 104 and into the first midsole volume 120. The first material may surround the first tongue 124 and conform to the shape of the first adhesion surface 200. The first material may adhere to the upper 1 18 if the first midsole volume 120 is shaped in that manner.

[0039] The first insert 104 may then be removed, as shown in FIG. 2C, to open the second midsole volume 214.

[0040] Then, as shown in FIG. 2D, a second material may be injected through the sprue channel 208 and the channel 212 of the second insert 106 and into the second midsole volume 214. The second material does not enter the first midsole volume 120 due to the presence of the previously injected first material. The injected second material may form a tongue 213 of second material in the volume previously occupied by the tongue 124 of first insert 104. At the first adhesion surface 200, the second material may adhere to the first material present in the first midsole volume 120. The second material may also surround the second tongue 204 and conform to the shape of the second adhesion surface 206. Further, the second material may adhere to the upper 118 at the upper adhesion surface 202. [0041] The second insert 106 may then be removed, as shown in FIG. 2E, to open a third midsole volume 216.

[0042] Subsequently, as shown in FIG. 2F, a third material may be injected through the sprue channel 208 and into third midsole volume 216. The third material is contained within the third midsole volume 216 due to the presence of the previously injected first and second materials. The injected third material may form a tongue 217 of third material in the volume previously occupied by the tongue 204 of the second insert 106. The third material may adhere to the second material at the second adhesion surface 206. The third material may also adhere to the upper 118 at an upper adhesion surface 218.

[0043] Then, as shown in FIG. 2G, an outsole 220 may be molded or otherwise attached to the completed midsole 222 formed of volumes of first, second, and third materials 224, 226, 228. As shown, the completed midsole 222 includes a sequence of adjacent volumes of injected midsole material 224, 226, 228 positioned along the length 122 of the midsole 222. A volume of injected midsole material 226, 228 includes a tongue 213, 217 that contacts an adjacent volume of injected midsole material 224, 226 at a respective adhesion surface that increases bonding surface area and strengthens the midsole 222.

[0044] The inserts and the materials used to fill the volumes defined by the inserts may be selected to provide a configurable midsole profile along the length 122 of the article of footwear. For example, a composition with relatively high stiffness may be used to fill a midsole volume at the heel, whereas a midsole volume positioned near the center of the article of footwear may be provided with a low stiffness material. In addition or alternatively, color or other characteristic may be varied. With regard to color, exposed portions of the midsole, such as at the side of the article of footwear, may be provided with a unique appearance by varying the color of material color injected into the midsole volumes.

[0045] FIG. 3A shows an example insert 104 viewed from above. A tongue 124 of the insert may extend in a lengthwise direction. The tongue 124 may have a lower surface 300 that defines a midsole adhesion surface 200, as shown in FIG. 2A, to facilitate bonding between adjacent injections of midsole material. The lower surface 300 may be textured or may have surface features to increase adhesion surface area to promote adhesion strength. The tongue 124 may have a top surface 302 that defines an upper adhesion surface 202, as shown in FIG. 2A, to facilitate bonding to a footwear upper. The top surface 302 may be textured or may have surface features to increase adhesion surface area to promote adhesion strength. The insert 104 may include a recess 304 to receive a tongue of another insert. The recess 304 may be shaped to engage with the tongue of the other insert. In other examples, such as with an insert 106 located at a heel, as shown in FIG. 2A, the recess 304 is omitted. Also shown in FIG. 3A is an opening 306 of a material delivery channel 210, as shown in FIG. 2A, that extends through the insert 104.

[0046] FIG. 3B shows the example insert 104 viewed from below. The insert may have a bottom surface 308 that defines a bottom surface of injected midsole material that is to adhere to an outsole. The bottom surface 206 may textured or may have surface features to increase adhesion surface area to promote adhesion strength. An opening 310 of a material delivery channel 210, as shown in FIG. 2A, may be located on the lower surface 300 of the tongue

124.

[0047] FIG. 4 shows an example insert 400 that includes an example surface feature to increase midsole material adhesion strength. A lower surface 300 of a tongue 124 of the insert 400 may indude a protrusion 402 that extends outwardly. Any number of protrusions may be provided. If the insert is to abut another insert during the molding process, then the other insert may have a suitable shaped recess to receive the protrusion. Material that is injected to the vidnity of the protrusions 402 may conform to the shape of the protrusions 402, thereby leaving recesses to be filled by subsequently injected material. Hence, the protrusions 402 may increase bonding surface area between adjacent injected materials. [0048] FIG. 5 shows another example insert 500. The insert 500 includes an open channel 502 on a bottom surface 308. The open channel 502 is to delivery injection molding material through the insert, similar to the enclosed material delivery channel 210 shown in FIG. 2A. The open channel 502 provide for simplified removal of molding material from the channel. If material remains adhered to the insert when the insert 500 is removed from a mold cavity, then such residual material is exposed and readily accessible for removable.

[0049] FIG. 6 shows additional example first and second inserts 600, 602, where the second insert 602 replaces the first insert 600 in a mold cavity after injection of material using the first insert 600. That is, the first and second inserts 600, 602 are not present in the mold cavity at the same time. The first insert 600 encompasses the volume of the second insert 602 as well as additional volume and define a first midsole volume. The second insert 602 is smaller than the first insert 600 and thereby opens a second midsole volume that is the differential volume between the inserts 602, 600. The first and second inserts 600, 602 may be used with the apparatuses and methods described elsewhere herein.

[0050] FIGs. 7A-7D show various examples of tongues that may be used to bond adjacent injected materials. FIG. 7A shows an example tongue 700 having inflected curvature. FIG. 7B shows an example convex tongue 702. FIG. 7B shows an example tongue 704 having planar surfaces. FIG. 7C shows different shaped of tongues used in the same set of inserts. As can be seen, various examples tongues have geometry that increases surface area for adhesion and allows for removal and insertion an insert with respect to injected material.

[0051] FIG. 8 shows an example method 800 of manufacture of a midsole of an article of footwear wherein a midsole is progressively defined by positioning inserts in a mold cavity. The method 800 may be performed by the example apparatus 100 of FIG. 1. The method may be performed by other apparatuses. FIGs. 2A-2G may be references for example structure. The method begins at block 802. [0052] At block 804, a first insert is used to define within a mold cavity a first midsole volume of a midsole of an article of footwear. An insert may be positioned in the cavity by a robot or human operator. A second insert may also be inserted into the mold cavity at this time, so that the first and second inserts are present in the mold cavity at the same time. An upper of the article of footwear may be provided to the mold cavity on, for example, a last. The mold cavity may then be closed.

[0053] At block 806, a first material is injected into the mold cavity to fill the first midsole volume with first material. The first material may be selected to have a specific characteristic, such as material composition, density, color, stiffness, or similar, that may be tailored to the specific article of footwear or the intended wearer. The first material may adhere to the upper as it is injected. The mold cavity may then be opened.

[0054] At block 808, a second insert is used to define within the mold cavity a second midsole volume of the article of footwear. The second midsole volume is adjacent to the first midsole volume along a length of the midsole under manufacture. In some examples, the second insert replaces the first insert to open the second midsole volume (e.g., see inserts 600, 602 of FIG. 6). In other examples, the first insert is removed from the mold cavity to open the second midsole volume (e.g. see FIGs. 2A-2G).

[0055] At block 810, a second material is injected into the mold cavity to fill the second midsole volume to form a tongue of second material to bond to the first material present in the first midsole volume. The second material may be selected to have a specific characteristic, such as material composition, density, color, stiffness, or similar, that is different from the first material and that may be tailored to the specific article of footwear or intended wearer. The second material may also adhere to the upper as it is injected.

[0056] The method 800 ends at block 812 with the formation of a midsole having a sequence of materials of different characteristics along the length of the midsole. [0057] FIG. 9 shows an example method 900 of manufacture of a midsole of an article of footwear wherein a midsole is progressively defined by positioning inserts in a mold cavity. The method 900 may be performed by the example apparatus 100 of FIG. 1. The method may be performed by other apparatuses. FIGs. 2A-2G may be references for example structure. The method begins at block 902.

[0058] At block 904, data of a wearer's foot is captured. This may be done by a three-dimensional (3D) scan or other measurement technique to capture the shape of the foot, pressure plate analysis, gait analysis, or similar biometric measurement techniques. Such captured data may be used to determine the structure and composition of the midsole to be manufactured.

[0059] At block 906, a plurality of inserts is selected based on the data captured for the wearer’s foot. The shapes and sizes of the inserts may be selected as specific to the wearer. The number of inserts, and therefore the number of zones of midsole material variance, may be selected as specific to the wearer. An insert may be selected from a library of stock inserts. An insert may be created on-demand, such as by 3D printing.

[0060] At block 908, a plurality of midsole materials. The midsole materials correspond to the plurality of inserts. The materials may be selected for characteristics such as material composition, density, color, stiffness, and so on. The materials may be selected based on the wearer's wants or needs regarding appearance, support, posture, intended use of the footwear, and similar.

[0061 ] Hence, the midsole of the footwear may be customized to the wearer. A part of such customization may be based on the selected inserts and their geometry. Another part of such customization may be based on the selected materials.

[0062] After the inserts and materials are selected, at block 910, a midsole volume may be defined within a mold cavity by using an insert or inserts in the mold cavity. Using an insert may include the insertion, removal, or replacement of an insert. As discussed elsewhere herein, inserts may cooperate to form a midsole volume, an insert may be removed to define a midsole volume, or an insert may be replaced to define a midsole volume.

[0063] After a midsole volume is defined in the mold cavity, the mold may be closed and prepared for injection. A selected material may then be injected into the midsole volume, at block 912.

[0064] A subsequent midsole volume may be defined within the mold cavity by using an insert or inserts, at block 910, and a corresponding material may be injected into such midsole volume, at block 912, until the midsole is complete, at block 914.

[0065] The method ends at block 916 with the formation of a midsole having a customized sequence of differing materials along its length specific to the wearer.

[0066] In view of the above, it should be apparent that the techniques described herein provide for readily customizable midsoles specific to a single wearer or group of wearers. Inserts may be used to define midsole volumes for materials of different characteristics. An insert may define a tongue that increases adhesion surface area between adjacent injected materials to increase the strength of the midsole, which may otherwise be weakened by use of different materials injected at different times.

[0067] It should be recognized that features and aspects of the various examples provided above can be combined into further examples that also fall within the scope of the present disclosure. In addition, the figures are not to scale and may have size and shape exaggerated for illustrative purposes.