Footwear heel spring device

Abstract

An apparatus configured to surround a portion of a foot receiving cavity (1839) in a heel region (13) of a footwear item includes a control bar having a central segment, a first side arm extending from the central segment, and a second side arm spaced from the first side arm and extending from the central segment. The control bar may include a series of slats. A base supports the control bar and is connected to the first side arm and the second side arm. The control bar is biased to a stress-free position in which the central segment is a first distance (D1, D2) from the base and elastically bends to a loaded position (10A, 910A, D2) under the action of an applied force in which the central segment is a second distance (D1, D2) from the base that is less than the first distance (D1, D2). The apparatus stores potential energy that causes the control bar to return to the unloaded position when the applied load is removed.

Description

[0001] This application is a divisional application of the patent application for invention titled "Heel Spring Device for Footwear" with the application date of October 25, 2017, application number 201780066079.X.

[0002] Cross - reference to related applications

[0003] This application claims the benefit of the priority of U.S. Provisional Application No. 62 / 413,062, filed on October 26, 2016, and also claims the benefit of the priority of U.S. Provisional Application No. 62 / 532,449, filed on July 14, 2017, both of which are incorporated herein by reference in their entirety. Technical field

[0004] This teaching generally includes a heel spring device for an article of footwear. Background art

[0005] Traditionally, placing footwear on the foot typically requires using one or both hands to stretch the ankle opening of the footwear upper and hold the rear portion during foot insertion, especially in cases where the upper is relatively soft and / or the upper does not have a heel counter with a flexible fabric fixed to the rearward - facing flexible fabric of the ankle opening. Brief description of the drawings

[0006] Figure 1 is a schematic perspective view of a heel spring device of an article of footwear in an unloaded position.

[0007] Figure 2 is Figure 1 a schematic plan view of the device of

[0008] Figure 3 is a schematic rear view of the device of Figure 1 fixed to the sole layer of the footwear, with the loaded position shown in dashed lines.

[0009] Figure 4 is a schematic partial cross - sectional view of the device of Figure 3 in Figure 3 and the sole layer of the footwear taken along line 4 - 4 in

[0010] Figure 5 is a schematic partial side view of the outer side of an article of footwear including the Figure 4 device, the footwear upper, and the sole layer of the footwear.

[0011] Figure 6 is Figure 5 a schematic partial side view of the inner side of the article of footwear of

[0012] Figure 7 Schematic of a partial side view of the inner side of an alternative embodiment of a footwear item including an optional heel spring device.

[0013] Figure 8 Is Figure 7 Schematic of a partial side view of the outer side of a footwear item.

[0014] Figure 9 Schematic of a perspective view of an alternative embodiment of a footwear item including an optional heel spring device.

[0015] Figure 10 Schematic of a side view of the inner side of an alternative embodiment of a footwear item including an optional heel spring device.

[0016] Figure 11 Schematic of a partial side view of the outer side of an alternative embodiment of a footwear item including an optional heel spring device.

[0017] Figure 12 Is Figure 11 Schematic of a rear view of a footwear item.

[0018] Figure 13 Is Figure 11 Schematic of a partial plan view of a footwear item.

[0019] Figure 14 Is Figure 13 Of Figure 13 Schematic of a partial cross-sectional view of a footwear item taken along line 14-14 in

[0020] Figure 15 Schematic of a partial side view of the outer side of an alternative embodiment of a footwear item including an optional heel spring device.

[0021] Figure 16 Schematic of a partial side view of the outer side of an alternative embodiment of a footwear item including an optional heel spring device.

[0022] Figure 17 Schematic of a partial side perspective view of the outer side of an alternative embodiment of a footwear item including an optional heel spring device.

[0023] Figure 18 Is Figure 17 Schematic of a rear perspective view of a footwear item.

[0024] Figure 19 Schematic of a partial perspective view of an alternative embodiment of a footwear item including an optional heel spring device.

[0025] Figure 20 Schematic diagram of a perspective view of an alternative embodiment of a footwear item including an optional heel spring device.

[0026] Figure 21 Is Figure 20 Schematic diagram of a perspective view of the heel spring device of

[0027] Figure 22 Is Figure 21 Schematic diagram of another perspective view of the heel spring device of , and the loading position is shown in dashed lines.

[0028] Figure 23 Shows a representative graph of force in Newtons versus displacement in millimeters during loading and unloading of the heel spring device within the scope of the present teachings.

[0029] Figure 24 Schematic diagram of a perspective view of an alternative embodiment of a footwear item including an optional heel spring device.

[0030] Figure 25 Is Figure 24 Schematic diagram of a perspective view of the heel spring device of

[0031] Figure 26 Schematic diagram of a perspective view of an alternative embodiment of a footwear item including an optional heel spring device.

[0032] Figure 27 Is Figure 26 Schematic diagram of a perspective view of the heel spring device of

[0033] Figure 28 Schematic diagram of a side view of the inner side of an alternative embodiment of a heel spring device for a footwear item.

[0034] Figure 29 Is Figure 28 Schematic diagram of a rear view of the heel spring device of

[0035] Figure 30 Schematic diagram of a perspective view of an alternative embodiment of a heel spring device for a footwear item.

[0036] Figure 31 Is Figure 30 Schematic diagram of a side view of the outer side of the heel spring device of

[0037] Figure 32 Schematic diagram of a partial side perspective view of the outer side of an alternative embodiment of a footwear item including an optional heel spring device.

[0038] Figure 33 Schematic diagram of a partial perspective view of an alternative embodiment of a footwear item including an optional heel spring device.

[0039] Figure 34 It is a schematic diagram of a perspective view of an alternative embodiment of a heel spring device for a footwear item.

[0040] Figure 35 It is Figure 34 a schematic diagram of a rear view of a heel spring device fixed to a shoe upper.

[0041] Figure 36 It is a schematic diagram of a perspective view of an alternative embodiment of a heel spring device for a footwear item.

[0042] Figure 37 a schematic diagram of a perspective view of a footwear item having a Figure 36 heel spring device in an unloaded position.

[0043] Figure 38 a schematic diagram of a perspective view of a footwear item having a heel spring device in a loaded position. Figure 37

[0044] Figure 39 It is a schematic diagram of a perspective view of an alternative embodiment of a footwear item having a heel spring device in an unloaded position.

[0045] Figure 40 a schematic diagram of a perspective view of a footwear item having a heel spring device in a loaded position. Figure 39

[0046] Figure 41 It is a schematic diagram of a perspective view of an alternative embodiment of a heel spring device for a footwear item.

[0047] Figure 42 a schematic diagram of a perspective view of a footwear item having a Figure 41 heel spring device in an unloaded position.

[0048] Figure 43 a schematic diagram of a perspective view of a footwear item having a heel spring device in a loaded position. Figure 42

[0049] Figure 44 It is a schematic diagram of a perspective view of an alternative embodiment of a heel spring device for a footwear item.

[0050] Figure 45 a schematic diagram of a partial perspective view of a footwear item having a Figure 44 heel spring device in an unloaded position.

[0051] Figure 46 a schematic diagram of a perspective view of a footwear item having a heel spring device in a loaded position. Figure 45 ​​​Schematic diagram of a partial perspective view of a footwear item.

[0052] Figure 47 Schematic diagram of a partial perspective view of an alternative embodiment of a heel spring device for a footwear item.

[0053] Figure 48 Is a footwear item having Figure 47 Schematic diagram of a partial perspective view of a heel spring device in an unloaded position.

[0054] Figure 49 Schematic diagram of a perspective view of a footwear item having an alternative embodiment of a heel spring device in an unloaded position and showing the loaded position in dashed lines.

[0055] Figure 50 Schematic diagram of a partial side view of a footwear item having an alternative embodiment of a heel spring device in an unloaded position.

[0056] Figure 51 Is a footwear item having a heel spring device in a loaded position Figure 50 Schematic diagram of a partial side view.

[0057] Figure 52 Schematic diagram of a perspective view of an alternative embodiment of a heel spring device in an unloaded position and showing the partial upper and sole structure in dashed lines.

[0058] Figure 53 Schematic diagram of a side view of a footwear item having an alternative embodiment of a heel spring device in an unloaded position and showing the loaded position in dashed lines.

[0059] Figure 54 Schematic diagram of a partial perspective view of a footwear item having an alternative embodiment of a heel spring device in an unloaded position.

[0060] Figure 55 Is Figure 54 Schematic diagram of a side perspective view of the outer side of a heel spring device in an unloaded position.

[0061] Figure 56 Is Figure 54 Schematic diagram of a perspective outer view of a heel spring device in a loaded position.

[0062] Figure 57 Is Figure 54 Schematic diagram of a front view of a heel spring device.

[0063] Figure 58 Is Figure 57 Along Figure 57 Schematic cross-sectional view of a heel spring device taken along line 58-58 in

[0064] Figure 59 is a schematic partial side view of a portion of a footwear item that includes a strap secured to an upper Figure 54 of the footwear item

[0065] Figure 60 is Figure 59 a schematic partial view of a portion of the strap

[0066] Figure 61 is a schematic perspective view of a footwear item of an alternative embodiment having a heel spring assembly in an unloaded position

[0067] Figure 62A is Figure 61 a schematic perspective side view of the heel spring assembly in the unloaded position

[0068] Figure 62B is Figure 62A a schematic perspective side view of the heel spring assembly in a loaded position

[0069] Figure 63 is Figure 61 a schematic perspective rear view of the heel spring assembly in the unloaded position with a compressible insert removed

[0070] Figure 64 is Figure 61 a schematic perspective inner view of the compressible insert of the heel spring assembly in the unloaded position

[0071] Figure 65 is along Figure 66 line 65-65 in Figure 66 a schematic cross-sectional view of the heel spring assembly

[0072] Figure 66 is Figure 61 a schematic front view of the heel spring assembly

[0073] Figure 67 is a schematic partial perspective view of a footwear item of an alternative embodiment having a heel spring in an unloaded position

[0074] Figure 68 is a schematic perspective view of a footwear item of an alternative embodiment having a heel spring assembly in an unloaded position

[0075] Figure 69 is Figure 68 a schematic perspective view of the heel spring assembly in the unloaded position, wherein the heel spring assembly

[0076] Figure 70 Is Figure 69 A schematic front view of the heel spring device.

[0077] Figure 71A Is Figure 70 Of the Figure 70 Schematic cross-sectional view of the heel spring device taken along line 71A-71A in

[0078] Figure 71B Is in the loaded position Figure 71A Schematic cross-sectional view of the heel spring device.

[0079] Figure 72 Is a schematic perspective rear view of an alternative embodiment of the heel spring device in the unloaded position.

[0080] Figure 73 Is a schematic perspective rear view of an alternative embodiment of the heel spring device in the unloaded position.

[0081] Figure 74 Is a schematic perspective view of a footwear item having an alternative embodiment of the heel spring device in the unloaded position.

[0082] Figure 75 Is Figure 74 Schematic perspective side view of the heel spring device in the unloaded position of

[0083] Figure 76 Is Figure 75 Of the Figure 75 Schematic cross-sectional view of the heel spring device taken along line 76-76 in

[0084] Figure 77 Is Figure 74 Schematic side view of the heel spring device in the unloaded position of

[0085] Figure 78 Is in the loaded position Figure 74 Schematic side view of the heel spring device.

[0086] Figure 79 Is a schematic perspective view of an alternative embodiment of the heel spring device in the unloaded position.

[0087] Figure 80 Is having Figure 79 Schematic view of the outer side of a footwear item with a heel spring device.

[0088] Figure 81 Is Figure 80 Schematic view of the inner side of a footwear item.

[0089] Figure 82 Is Figure 80 A schematic rear view of a footwear item.

[0090] Figure 83 Is Figure 80 A plan view of the midsole of a footwear item.

[0091] Figure 84 Is Figure 83 A plan view of the midsole, where Figure 79 The heel spring assembly is seated in a recess of the midsole.

[0092] Figure 85 A schematic perspective view of an alternative embodiment of the heel spring assembly in an unloaded position.

[0093] Figure 86 Is Figure 85 A schematic perspective view of another perspective of the heel spring assembly.

[0094] Figure 87 Is a schematic of a footwear item having Figure 85 The heel spring assembly and shows the upper in dashed lines.

[0095] Figure 88 Is Figure 85 A schematic partial plan view of the arm of the heel spring assembly connected to a component of the footwear upper.

[0096] Figure 89 Is Figure 87 A schematic plan view of the midsole of a footwear item.

[0097] Figure 90 Is Figure 85 Seated in Figure 89 A schematic plan view of the heel spring assembly seated in a recess of the midsole.

[0098] Figure 91 Is Figure 85 An exploded partial view of the heel spring assembly, where a tab of the upper extends through a hole in the heel spring assembly and a pin is shown.

[0099] Figure 92 Is Figure 85 A partial view of the heel spring assembly, where the heel spring assembly has a tab fixed in a loop and where a pin is inserted in the loop.

[0100] Figure 93 A schematic plan view of an alternative embodiment of the heel spring assembly.

[0101] Figure 94 Is including Figure 93Schematic rear view of a footwear item with a heel spring device. DETAILED DESCRIPTION

[0102] Disclosed herein are heel spring devices for facilitating foot entry into a footwear item. Each heel spring device can enable hands-free foot entry, such as by using the foot to load the heel spring device to enter the foot receiving cavity from a rear position and sliding the foot forward and downward into the foot receiving cavity.

[0103] Within the scope of the present disclosure, a device for facilitating foot entry into a foot receiving cavity of a footwear item is configured to surround a portion of the foot receiving cavity in a heel region of the footwear item and includes a control bar having a central segment, a first side arm extending from the central segment, and a second side arm spaced from the first side arm and extending from the central segment. A continuous base can support the control bar and can be connected to both the first side arm and the second side arm. The control bar is biased to an unloaded position where the central segment is a first distance from the base, and the control bar elastically deforms to a loaded position under the action of an applied force where the central segment is a second distance from the base that is less than the first distance. The device stores potential energy that returns the control bar to a stress-free position when the applied load is removed.

[0104] In one or more embodiments of the device, the base is connected to the first side arm at a first joint and the base is connected to the second side arm at a second joint. The joints may be referred to herein as hinge joints or hinge junctions.

[0105] The device including the control bar and the base can be a single, integral, one-piece component. For example, in one or more embodiments, the control bar has an arcuate shape and the base has an arcuate shape. Thus, the control bar and the base are configured as a full elliptical leaf spring.

[0106] In one or more embodiments of the device, the base has a central segment, a first base arm, and a second base arm all disposed in a common plane. The first base arm is spaced from the second base arm and both extend from the central segment of the base. The first base arm and the first side arm are connected at a first joint. The second base arm and the second side arm are connected at a second joint. When the control bar is in the unloaded position, the first side arm and the second side arm extend at an acute angle relative to the common plane of the base. When the control bar is depressed, the first side arm and the second side arm extend at a second acute angle relative to the common plane of the base. The second acute angle is less than the first acute angle.

[0107] In one or more embodiments of the device, when the control bar is in the loaded position, the first and second side arms bow apart from one another. In the case where a footwear upper is attached to the side arms, when the side arms bow apart, the foot receiving cavity of the footwear upper opens wider, thus further facilitating entry of the foot into the foot receiving cavity.

[0108] In one or more embodiments of the device, one of the control bar and the base has an extension extending towards the other of the control bar and the base. When the control bar is in the stress-free position, the extension is spaced apart from the other of the control bar and the base, and when the control bar is in the loaded position, the extension contacts the other of the control bar and the base, thereby restricting further downward pressing of the control bar. The extension thus limits the amount of deformation, such as by preventing the second angle from becoming too small, thereby preventing plastic deformation.

[0109] In one or more embodiments of the device, the central segment of the control bar has an extension extending towards the base, and the base has a recess. When the control bar is in the unloaded position, the extension is spaced apart from the base, and when the control bar is pressed down to the loaded position, the extension projects into the recess. Docking of the control bar and the base by the extension and the recess also restricts side to side movement of the control bar relative to the base.

[0110] In one or more embodiments of the device, the central segment of the control bar has a ramped surface that slopes towards the inner perimeter of the central segment between the first and second side arms. The ramped surface helps to guide the foot downward and forward into the foot receiving cavity during application of a downward force on the control bar.

[0111] In one or more embodiments of the device, the first and second side arms each twist outwardly from the base to the central segment of the control bar along their respective longitudinal axes. The outward twisting helps to promote downward and backward movement of the central segment during foot loading.

[0112] In one or more embodiments of the device, the first and second side arms are asymmetric about a longitudinal axis extending through the base between the first and second side arms. For example, the first side arm can be the medial arm, and the second side arm can be the lateral arm. Similar to the shape of a typical heel region of a foot, the medial arm can be shorter than the lateral arm and can have a greater outer curvature than the lateral arm.

[0113] In one or more embodiments of the device, the base has a flange that extends inwardly. For example, the flange can be seated in a recess and secured to a foot-receiving surface of a footwear sole structure in a heel region of the sole structure.

[0114] In one or more embodiments of the device, the footwear sole structure can have an outer wall with a recess in the heel region, and the base of the device can be at least partially seated in the recess and secured to the outer wall of the sole structure.

[0115] In one or more embodiments of the device, the base can be located below a control bar, where a first side arm is located at an inner side surface of a shoe upper that defines at least a portion of an ankle opening, a second side arm is located at an outer side surface of the shoe upper, and a central segment of the control bar is located behind the ankle opening of the shoe upper.

[0116] In one or more embodiments of the device, a foremost portion of an inner surface of the first side arm includes a medial recess such that the first side arm is thinner at the medial recess than behind the medial recess, and a foremost portion of an inner surface of the second side arm includes a lateral recess such that the second side arm is thinner at the lateral recess than behind the lateral recess. The shoe upper can be secured to the first side arm at the medial recess and to the second side arm at the lateral recess.

[0117] In one or more embodiments of the device, the central segment has a hole, and the footwear upper includes a tab that extends through the hole. The tab can be secured to a rear portion of the footwear upper. A pin can be secured to the tab behind the hole. The tab with the pin thereon can be wider than the hole such that the tab is anchored to the central segment by the pin.

[0118] In one or more embodiments of the device, a lever can extend outwardly from the control bar. The lever can assist in depressing the control bar.

[0119] In one or more embodiments, the heel device includes a bladder element that includes one or more fluid-filled internal cavities. The one or more fluid-filled internal cavities can include a cavity that extends along the central segment. The cavity that extends along the central segment can also extend along one or both of the first side arm or the second side arm and can be tubular in shape or other shape. The one or more fluid-filled internal cavities can further include one or more reservoirs that are disposed on one or both of the first side arm and the second side arm and are in fluid communication with the cavity that extends along the central segment. When the heel spring device resiliently deforms under an applied force, the one or more reservoirs expand as fluid is transferred from the cavity that extends along the central segment.

[0120] The base of the device can be fixed to a flexible footwear upper that defines at least a portion of an ankle opening such that the base is located below the control bar, where the first side arm is located at the inner side of the footwear upper, the second side arm is located at the outer side of the footwear upper, and the central segment of the control bar is located behind the ankle opening. The base can extend from the outer side to the inner side around the rearmost portion of the footwear upper. The control bar can be embedded within the footwear upper.

[0121] The flexible footwear upper can define a foot receiving space (also referred to as a foot receiving cavity), and the base can be located below the foot receiving space. The base can be coupled to the foremost portions of the first and second side arms. The base can extend rearwardly from the control bar, the base can extend forwardly from the control bar, or the base can extend both rearwardly and forwardly from the control bar.

[0122] In one or more embodiments, the base has a forwardly extending protrusion located below the foot receiving space adjacent to the inner side of the footwear upper, and a rearwardly extending protrusion located below the foot receiving space along the outer side of the footwear upper.

[0123] In one or more embodiments, a sole structure is fixed to the footwear upper and is located below the foot receiving space. The sole structure has a foot-facing surface with a recess, and the base has a main portion and a protrusion extending from the main portion, and the protrusion is configured to be located within the recess.

[0124] In one or more embodiments of the device, the central segment of the control bar has a hole. A heel pull tab of the upper can extend through the hole to further secure the footwear upper to the device. The device can have a thinned portion that enables the device to be stitched to the upper through the thinned portion.

[0125] In one or more embodiments of the device, the control bar is embedded within the footwear upper. For example, the device can be covered by layers of a flexible covering of the footwear upper and be sandwiched between those layers.

[0126] In one or more embodiments of the device, the base of the device is the sole structure of a footwear item. In another embodiment of the device, the base is a flexible footwear upper. In such an embodiment, the upper provides elastic flexure at the junction with the control bar.

[0127] In one or more embodiments of the device, the first side arm and the second side arm each have at least one slot extending therethrough. In one or more embodiments, at least one slot extending through the first side arm may extend through the first side arm along the length of the first side arm, and at least one slot extending through the second side arm may extend through the second side arm along the length of the second side arm. In alternative embodiments, at least one slot extending through the first side arm extends transversely to the length of the first side arm, and at least one slot extending through the second side arm extends transversely to the length of the second side arm.

[0128] Within the scope of the present disclosure, a heel spring device for facilitating foot entry into a footwear item is configured to surround a portion of a foot receiving cavity in a heel region of the footwear item and includes a control bar and a base located below the control bar. In one or more embodiments, the control bar includes a series of slats. Each slat has a central segment, an inner arm extending from the central segment to an inner end that is connected to an inner side of the base, and an outer arm extending from the central segment to an outer end that is connected to an outer side of the base. The control bar is biased to an unloaded position and elastically bends to a loaded position under the action of an applied force, in which at least one central segment is closer to the base than in the unloaded position, thereby storing potential energy that causes the control bar to return to the unloaded position when the applied load is removed. For example, the control bar and the base may be configured as a full elliptical leaf spring.

[0129] The device stores potential energy, such as elastic energy and / or spring energy, which causes the control bar to return to a stress-free position when the applied load is removed. As used herein, elastic bending may also be referred to as resilient bending and causes resilient deformation or elastic deformation. For example, the foot may press down on the control bar and slide into the foot receiving cavity of the attached footwear upper without the use of hands or any tools to adjust the upper to allow foot entry.

[0130] In one or more embodiments of the device, the control bar defines slots extending between the slats. When the control bar is in the unloaded position, the slats are spaced apart from each other by the slots. The slots may close between the slats such that one or more adjacent central segments contact each other in the loaded position. The slots may be parallel to each other, and the exterior sides of the slats may be flush with each other in the unloaded position.

[0131] In one or more embodiments of the device, the lowermost slat at the central segment closest to the base is shorter from the inner end to the outer end than the uppermost slat farthest from the central segment from the inner end to the outer end. In one or more embodiments, the lowermost slat is thinner than the uppermost slat. In one or more embodiments of the device, the lowermost slat has a tab extending from the lower edge of the central segment. The outer surface of the base may have a peripheral recess extending from the lower edge of the base. For example, the peripheral recess may receive a flange of the sole structure.

[0132] In one or more embodiments of the device, the elastic insert at least partially fills the groove. The elastic insert may include an elastically compressible material, such as at least one of rubber or thermoplastic polyurethane, and may be a foam, but is not limited to these materials. The elastic insert may include a sleeve extending along the inner side surface of the slat, and spaced protrusions extending from the sleeve into the groove. In one or more embodiments of the device, the elastic insert is configured as a pleated member that extends outward from the inner side of the slat between the slats.

[0133] Within the scope of the present disclosure, a heel spring device for facilitating foot entry into a footwear item is configured to surround a portion of a foot receiving cavity in the heel region of the footwear item and includes an elastic corrugated body that includes a central segment, an inner arm extending forward from the central segment, and an outer arm extending forward from the central segment. The corrugated body may include alternating ridges and grooves that extend in the longitudinal direction along the inner arm, the central segment, and the outer arm. The corrugated body is biased to an unloaded position and is compressed to a loaded position under the action of an applied force, with adjacent ridges in the alternating ridges being closer to each other in the loaded position than in the unloaded position, thereby storing elastic energy that causes the corrugated body to return to the unloaded position when the applied load is removed.

[0134] For example, the corrugated body may include a bellow. The ridges may be the pleats of the bellow, and the grooves may be the folds of the bellow. The corrugated body may be an elastically deformable material, such as at least one of rubber or thermoplastic polyurethane, and may be an elastic foam (e.g., a polymer foam material, etc.), but is not limited to these materials.

[0135] In one or more embodiments of the device, a first set of ridges and grooves extends from the inner arm to the outer arm, and a second set of ridges and grooves extends only along the central segment.

[0136] The device may include an upper flange extending along an upper edge of the corrugated body at a central segment and may also include a lower flange extending along a lower edge of the corrugated body at the inner arm, central segment, and outer arm.

[0137] Within the scope of the present teachings, an article of footwear includes an upper defining at least a portion of an ankle opening, a sole structure secured to the upper and positioned below the upper, and a heel spring assembly. The heel spring assembly may include a central segment secured to the upper rearward of the ankle opening, an inner arm extending downwardly and forwardly from the central segment, an inner arm extending downwardly and forwardly from the central segment, and a base connecting to both the inner arm and the outer arm. The base may be secured to the sole structure. The central segment is biased to an unloaded position and the heel spring assembly elastically deforms to a loaded position under an applied force, with the central segment being closer to the base in the loaded position than in the unloaded position. The heel spring assembly stores elastic energy that causes the central segment to return to the unloaded position when the applied load is removed, and the upper moves with the central segment such that the ankle opening is closer to the sole structure when the central segment is in the loaded position than when the central segment is in the unloaded position.

[0138] In one or more embodiments of the article of footwear, the sole structure includes a midsole and the base is partially recessed into the midsole.

[0139] In one or more embodiments of the article of footwear, the inner arm is secured to an inner side of the upper and the outer arm is secured to an outer side of the upper. When the central segment is in the loaded position, the inner arm and the outer arm may bend laterally outwardly and away from each other to widen the ankle opening.

[0140] In one or more embodiments of the article of footwear, in the unloaded position, the central segment is spaced from the base and the device is characterized in that there is no rigid heel stabilizer between the central segment and the base at a rear portion of the junction of the inner arm and the base and at a rear portion of the junction between the outer arm and the base.

[0141] In one or more embodiments of the article of footwear, the inner arm and the outer arm each twist outwardly from the base to the central segment along their respective longitudinal axes.

[0142] In one or more embodiments of the article of footwear, one of the central segment and the base has an extension extending at least partially toward the other of the central segment and the base. When the central segment is in the unloaded position, the extension is spaced from the other of the central segment and the base. The extension may extend at least partially from the central segment toward the base. The base may have a recess. When the central segment is in the unloaded position, the extension may be spaced from the base and when the central segment is in the loaded position, the extension may project into the recess.

[0143] In one or more embodiments of a footwear item, an extension extends at least partially from a central segment toward a base, and the footwear item further includes a strap having a proximal end secured to the upper and a pocket at the distal end. The extension is disposed within the pocket. The strap may be outside of the central segment.

[0144] In one or more embodiments of a footwear item, an outer surface of the base has a peripheral recess extending from a lower edge of the base. A sole structure has a flange disposed within the peripheral recess.

[0145] In one or more embodiments of a footwear item, a heel spring assembly includes a bladder element that includes one or more fluid-filled internal cavities. The one or more fluid-filled internal cavities may include a cavity extending along the central segment. The cavity extending along the central segment may also extend along one or both of an inner arm or an outer arm and may be tubular or other shape. The one or more fluid-filled internal cavities may further include one or more reservoirs disposed at or at both of an inner arm and an outer arm and in fluid communication with the cavity extending along the central segment. When the heel spring assembly rebounds and deforms under an applied force, the one or more reservoirs expand as fluid transfers from the cavity extending along the central segment.

[0146] In one or more embodiments of a footwear item, the central segment has a ramp surface that slopes toward an inner perimeter of the central segment between the inner arm and the outer arm. In one or more embodiments, the heel spring assembly is a single, integral, one-piece component.

[0147] In one or more embodiments, a footwear upper includes a flexible covering that defines at least a portion of an ankle opening. The footwear upper includes a heel spring assembly that includes a control bar having a central segment secured to the flexible covering behind the ankle opening, an inner arm extending from the central segment and secured to an inner side of the flexible covering, and an outer arm extending from the central segment and secured to an outer side of the flexible covering. The heel spring assembly may further include a continuous base that supports the control bar and is connected to both the inner arm and the outer arm. The control bar is biased to an unloaded position where the central segment is a first distance from the base, and the control bar elastically deforms to a loaded position under an applied force where the central segment is a second distance from the base that is less than the first distance, and the device stores potential energy that returns the control bar to the unloaded position when the applied load is removed.

[0148] In one or more embodiments of a footwear upper, the flexible covering is an elastically stretchable fabric, and the footwear upper further includes a collar that is secured to the flexible covering and defines a front portion of an ankle opening. The collar is stiffer than the elastically stretchable fabric.

[0149] In one or more embodiments, the footwear upper further includes a heel tab that is secured to the flexible covering. A central segment of the control bar has a hole, and the heel tab extends through the hole.

[0150] In one or more embodiments of a footwear upper, when the central segment is in a loaded position, the medial arm and the lateral arm bend laterally outwardly and away from each other, thereby widening the ankle opening of the flexible covering.

[0151] In one or more embodiments, the footwear upper is characterized in that at a rear portion of the junction between the control bar and the base, there is no rigid heel stabilizer between the control bar and the base.

[0152] In one or more embodiments of a footwear upper, the medial arm and the lateral arm each twist outwardly from the base to the central segment of the control bar along their respective longitudinal axes.

[0153] In one or more embodiments of a footwear upper, one of the control bar and the base has an extension that extends toward the other of the control bar and the base. When the control bar is in an unloaded position, the extension is spaced apart from the other of the control bar and the base, and when the control bar is in a loaded position, the extension contacts the other of the control bar and the base, thereby restricting further downward pressing of the control bar.

[0154] In one or more embodiments of a footwear upper, the central segment of the control bar has an extension that extends toward the base, and the base has a recess. When the control bar is in a stress-free position, the extension is spaced apart from the base, and when the control bar is in a loaded position, the extension projects into the recess.

[0155] In one or more embodiments, the footwear upper includes a bladder element that includes one or more fluid-filled internal cavities. The one or more fluid-filled internal cavities may include a cavity that extends along the central segment. The cavity that extends along the central segment may also extend along one or both of the medial arm or the lateral arm, and may be tubular or other shapes. The one or more fluid-filled internal cavities may further include one or more reservoirs disposed at one or both of the medial arm and the lateral arm and in fluid communication with the cavity that extends along the central segment. When the heel spring means rebounds and deforms under the applied force, the one or more reservoirs expand as fluid is transferred from the cavity that extends along the central segment.

[0156] In one or more embodiments of a footwear upper, a central segment of a control bar has a ramp surface that slopes toward an inner perimeter of the central segment between an inner arm and an outer arm.

[0157] In one or more embodiments of a footwear upper, a heel spring device is a single, integral, one-piece component.

[0158] In one or more embodiments, an article of footwear includes a footwear upper that includes a flexible covering that defines at least a portion of an ankle opening. The article of footwear also includes a sole structure and a heel spring device that is secured to the footwear upper and is located below the footwear upper. The heel spring device can include a control bar that has a central segment secured to the flexible covering behind the ankle opening, an inner arm that extends downwardly and forwardly from the central segment, and an outer arm that extends downwardly and forwardly from the central segment. The heel spring device can also include a continuous base that supports the control bar and is connected to both the inner arm and the outer arm. The base can be secured to the sole structure. The control bar is biased to an unloaded position where the central segment is a first distance from the base, and elastically bends to a loaded position under an applied force where the central segment is a second distance from the base that is less than the first distance, and the device stores elastic energy that causes the control bar to return to the unloaded position when the applied load is removed. The flexible covering moves with the control bar.

[0159] In one or more embodiments of an article of footwear, the sole structure includes a midsole, and the base is partially recessed into the midsole. In one or more embodiments of an article of footwear, the inner arm is secured to an inner side surface of the flexible covering, and the outer arm is secured to an outer side surface of the flexible covering. In one or more embodiments of an article of footwear, when the central segment is in the loaded position, the inner arm and the outer arm bend laterally outwardly and away from each other to widen the ankle opening of the flexible covering. In one or more embodiments of an article of footwear, the article of footwear is characterized in that there is no rigid heel stabilizer between the control bar and the base at a rear portion of the junction between the control bar and the base.

[0160] In one or more embodiments of an article of footwear, each of the inner arm and the outer arm is twisted outwardly from the base to the central segment of the control bar along their respective longitudinal axes. In one or more embodiments of an article of footwear, one of the control bar and the base has an extension that extends toward the other of the control bar and the base. When the control bar is in the unloaded position, the extension is spaced apart from the other of the control bar and the base, and when the control bar is in the loaded position, the extension contacts the other of the control bar and the base to limit further depression of the control bar.

[0161] In one or more embodiments of the footwear item, an extension extends from a central segment of a control bar toward a base, the base having a recess, and the extension is spaced from the base when the control bar is in an unloaded position and projects into the recess when the control bar is in a loaded position. In one or more embodiments of the footwear item, the central segment of the control bar has a ramp surface that slopes toward the inner perimeter of the central segment between the inner arm and the outer arm. In one or more embodiments of the footwear item, the device is a single, integral, one-piece component.

[0162] In one or more embodiments, a footwear item includes a footwear upper that includes a flexible covering that defines at least a portion of an ankle opening, a sole structure that is secured to and located beneath the footwear upper, and a heel spring device. The heel spring device can include a control bar having a central segment that is secured to the flexible covering behind the ankle opening, an inner arm that extends downwardly and forwardly from the central segment along an inner side of the footwear upper, and an outer arm that extends downwardly and forwardly from the central segment along an inner side of the footwear upper. The heel spring device can also include a mechanical spring that is operatively connected to the control bar and biases the control bar to an unloaded position. The control bar can pivot rearwardly to a loaded position under the application of a force, thereby storing potential energy in the spring that causes the control bar to return to the unloaded position when the applied load is removed, and the flexible covering moves with the control bar.

[0163] In one or more embodiments of the footwear item, a pin is connected to both the inner arm and the outer arm and extends through the sole structure. A spring is wound around the pin and has one end secured to pivot with the control bar and the other end secured relative to the control bar.

[0164] In one or more embodiments, an article of footwear includes a footwear upper and a sole structure. The footwear upper includes a flexible covering that defines at least a portion of an ankle opening. The sole structure is secured to the upper and is located below the footwear upper. The article of footwear may also include a heel spring assembly. The heel spring assembly may include a rear control bar having a central segment secured to the flexible covering behind the ankle opening, a medial arm extending downwardly and forwardly from the central segment along an inner side of the footwear upper, and a lateral arm extending downwardly and forwardly from the central segment along the inner side of the footwear upper. The heel spring assembly may also include a front bar having a central segment secured to the flexible covering in front of the ankle opening, a medial arm extending downwardly and rearwardly from the central segment along the inner side of the upper, and a lateral arm extending downwardly and rearwardly from the central segment along the inner side of the upper. The front bar and the rear control bar may cross and be secured to one another at an outer side of the upper and at an inner side of the upper. The rear control bar is pivotable rearwardly to a loaded position under the application of a force, thereby storing potential energy that causes the front bar to return to an unloaded position when the applied load is removed, with the flexible covering moving with the rear control bar.

[0165] Within the scope of the present teachings, an article of footwear includes a footwear upper that includes a flexible covering that defines at least a portion of an ankle opening, a sole structure secured to the footwear upper and located below the footwear upper, and a heel spring assembly. The heel spring assembly may include a control bar and a continuous base. The control bar may have a central segment secured to the flexible covering behind the ankle opening, a medial arm extending from the central segment and secured to an inner side of the flexible covering, and a lateral arm extending from the central segment and secured to an outer side of the flexible covering. The base may support the control bar and may be connected to both the medial arm and the lateral arm and secured to the sole structure. The control bar is biased to an unloaded position in which the central segment is a first distance from the base, and the control bar is elastically bent to a loaded position under the application of a force in which the central segment is a second distance from the base that is less than the first distance. The device stores potential energy, such as elastic energy and / or spring energy, that causes the control bar to return to the unloaded position when the applied load is removed, with the flexible covering moving with the control bar.

[0166] Referring to the drawings, wherein like reference numerals represent like components, Figure 1 illustrated for facilitating foot entry Figure 5 and Figure 6The device 10 of the footwear item 12 shown in [reference]. The shoes herein are described as leisure shoes and athletic shoes, but the teachings herein also include footwear items for dress shoes, work shoes, sandals, slippers, boots, or any other category of footwear.

[0167] As Figure 5 shown, the device 10 is configured to surround a portion of the foot receiving cavity 47 at the heel region 13 of the footwear item 12. When a person's foot is supported on the sole structure 32 within the foot receiving cavity 47 and is sized to correspond to the footwear item 12, the heel region 13 generally includes the portion of the footwear item 12 that corresponds to the rear portion of the person's foot, including the ankle bone. The forefoot region 15 of the footwear item 12 (best shown in Figure 10 , Figure 80 and Figure 87 with respect to the footwear items 312, 3212, and 3312) generally includes the portion of the footwear item 12 that corresponds to the toes and the joints that connect the metatarsals and phalanges of the human foot (interchangeably referred to herein as the "metatarsophalangeal joint" or "MPJ" joint). The midfoot region 17 of the footwear item 12 (best shown in Figure 10 , Figure 80 and Figure 87 with respect to the footwear items 312, 3212, and 3312) is disposed between the heel region 13 and the forefoot region 15 and generally includes the portion of the footwear item 12 that corresponds to the arch region of the human foot, including the navicular joint.

[0168] The device 10 includes a control bar 14 that has a central segment 16, a first side arm 18 that extends downward and forward from the central segment 16, and a second side arm 20 that is spaced apart from the first side arm 18 and also extends downward and forward from the central segment 16. The first side arm 18 is the medial arm and the second side arm 20 is the lateral arm.

[0169] The device 10 also includes a base 22 that supports the control bar 14 and is connected to the control bar 14 at resiliently bendable junctions 24A, 24B. The base 22 is continuous and extends between and is connected to the first side arm 18 and the second side arm 20. The base 22 is continuous in that it does not break or pass through a connection of other components as it extends from the first side arm 18 to the second side arm 20. The base 22 has a central segment 26, a first base arm 28, and a second base arm 30 that are all disposed in a common plane. When the base 22 of the device 10 is resting on a horizontal surface, the common plane P is parallel to the horizontal surface, and in Figure 3is best indicated by a dashed line P, which represents a plane perpendicular to the page of the drawing. The first base arm 28 is spaced apart from the second base arm 30, and both extend from the central segment 26 of the base 22. As Figure 2 shown, the base 22 is slightly positioned below the control bar 14, thereby providing stability to the device 10 during depression.

[0170] The joints 24A, 24B include: a first joint 24A at which the base 22 and the first side arm 18 are connected; and a second joint 24B at which the base 22 and the second side arm 20 are connected. The first joint 24A connects the first base arm 28 to the first side arm 18. The second joint 24B connects the second base arm 30 to the second side arm 20.

[0171] The control bar 14 has an arcuate shape from the first joint 24A to the second joint 24B. Similarly, the base 22 has an arcuate shape from the first joint 24A to the second joint 24B. With this arrangement, the control bar 14 and the base 22 are configured as a full elliptical leaf spring as described herein. The device may be referred to as a heel spring. Additionally, the device 10 is a single, integral, one-piece component. For example, the device 10 may be injection molded as a single, integral, one-piece component.

[0172] The control bar 14 is biased to Figure 1 、 Figure 2 and Figure 3 the unloaded position shown in. The unloaded position is also referred to herein as the stress-free position. The control bar 14 is inherently biased to the stress-free position by its material in its formed state. In other words, the material of the control bar 14 has sufficient rigidity such that it remains in the stress-free position in its natural state (with no external load applied thereto), and will return to the stress-free position after elastic bending due to its elasticity. In the stress-free position, the central segment 16 is a first distance D1 from the base 22, as Figure 3 shown by the distance D1 from the top of the central segment 16 to the bottom of the base 22. The stress-free position is the position where the device 10 is in a relaxed, unloaded state (i.e., no vertical force is applied to the control bar 14). The control bar 14 can be depressed under the applied force F shown in Figure 4 , which represents the force applied by the foot 46 during insertion of the foot 46 into the foot receiving cavity 47 of the footwear item 12 (see Figure 5 and Figure 6 ). When loaded in this manner, the control bar 14 elastically bends to the loaded position, in which the central segment 16 is a second distance D2 from the base 22. When the device 10 is in the loaded position, the device 10 is in Figure 3It is represented by a dashed line and reference numeral 10A in the middle. The second distance D2 is less than the first distance D1. The difference between the distances D1 and D2 is the deflection of the device 10, and this deflection can be, but is not limited to, a deflection of 30 mm. The device 10 is configured such that when it is pressed down to the loading position D2 under the action of a force, it elastically bends at the joints 24A and 24B, thereby storing elastic energy. When the force F is removed, the stored elastic energy causes the control bar 14 to return to the stress-free position. In Figure 3 only the device 10 and the sole structure 32 are shown. In order to clearly show the positions of the devices 10 and 10A, the upper shoe upper 38 described herein is removed.

[0173] As shown in Figure 5 and Figure 6 the footwear article 12 includes a sole structure 32 and an upper shoe upper 38 fixed to the sole structure 32. The sole structure 32 includes one or more sole components, and the one or more sole components can be a shoe bottom layer 34, such as an outsole, a midsole, or an integral combination of an outsole and a midsole (which can be referred to as a unisole). In Figure 5 and Figure 6 the shoe bottom layer 34 can be a midsole or a unisole. The shoe bottom layer 34 is located below the upper shoe upper 38. The lower part 40 of the footwear upper 38 is fixed to the shoe bottom layer 34, such as by an adhesive or other means. The base 22 is fixed to the shoe bottom layer 34, such as by adhesive bonding, thermal bonding, or other means. The shoe bottom layer 34 can be formed with minute recesses on its outer surface, and the outer surface is shaped to allow the base 22 and the joints 24A and 24B to partially seat in these recesses, thereby being further supported by the shoe bottom layer 34.

[0174] The flexible footwear upper 38 defines at least a part of the ankle opening 39. The base 22 is located below the control bar 14 and is fixed to the upper shoe upper 38, wherein the first side arm 18 is fixed to the inner side surface 41 of the footwear upper 38, and the second side arm 20 is fixed to the outer side surface 43 of the footwear upper 38. As best shown in Figure 5 and Figure 6 the base 22 extends from the outer side surface 43 to the inner side surface 41 around the rearmost part of the footwear upper. The central section 16 of the control bar 14 is fixed to the footwear upper 38 behind the ankle opening 39. The device 10 can have a thinned portion 45 (best shown in Figure 3 which enables the footwear upper 38 to be machine stitched to the device at the thinned portion 45.

[0175] The upper shoe upper 38 can include a flexible covering 42 (also referred to as a flexible covering layer) for receiving and covering the foot 46 supported on the shoe bottom layer 34 (in Figure 4(as shown). For example, the flexible covering 42 can be a stretchable fabric that provides a lightweight and breathable feel, such as a four-way stretch nylon fabric. The footwear item 12 is characterized in that at the rear of the joints 24A, 24B between the control bar 14 and the base 22, there is no rigid heel stabilizer located between the control bar 14 and the base 22. The device 10 functions as a heel stabilizer at least in some aspects because it helps to keep the wearer's heel in place on the heel portion of the sole structure, thereby preventing medial or lateral displacement during use. Since the device 10 is fixed to the flexible covering 42, the device 10 together with the flexible covering 42 of the upper 38 can be referred to as the footwear upper. In other words, the device 10 can be considered as a component of a multi-component footwear upper, which also includes the flexible covering 42 and other components of the footwear item. The multi-component footwear upper can also be referred to as a footwear upper assembly.

[0176] Traditionally, slipping the foot into the upper typically requires using one or both hands during foot insertion to stretch the ankle opening and hold the rear portion, especially in the case of a relatively soft upper and / or when the upper does not have a heel stabilizer of flexible fabric fixed to the rear of the ankle opening. The device 10 alleviates these problems and allows the foot 46 to enter the foot receiving cavity 47 formed by the upper 38 without using hands or other tools. Only the foot 46 is needed to enter. Specifically, as shown in Figure 4 (not shown), using the bottom of the foot 46, a force F is applied to press on the control bar 14, causing the device to elastically bend at the joints 24A, 24B, thereby moving the control bar 14 from the stress-free position to the loaded position, which is represented by the control bar in position 14A. The upper 38 is attached to the central segment 16 and moves downward together with the control bar 14. When the foot 46 is fully moved into the foot receiving cavity 47, the elastic energy stored due to the biasing of the device 10 automatically returns the device 10 to the stress-free position, causing the upper 38 to be automatically pulled up on the rear of the foot 46. Figure 5 (not shown) shows the position of the stretchable flexible covering 42 before the foot is inserted. When the device 10 returns to the stress-free position, the flexible covering 42 stretches over the rear of the heel of the foot 46 to Figure 5 the position 42A shown by the dashed line in (not shown).

[0177] To further facilitate the entry of the foot 46 into the foot receiving cavity 47 of the upper 38, as shown in Figure 2 and Figure 4As shown, the central segment 16 of the control bar 14 has a ramp surface 50 that slopes towards the inner perimeter 52 of the central segment 16. Between the upper portion 54 of the foot contact surface of the control bar 14 and the ramp surface 50, the slope of the central segment 16 changes at the transition line 51. The ramp surface 50 has a steeper slope than the upper portion 54, thus facilitating the downward and inward sliding of the foot 46.

[0178] Reference Figure 5 and Figure 6 , when the control bar 14 is in the stress-free position, the first side arm 18 and the second side arm 20 extend at a first acute angle A1 relative to the common plane P of the base 22. The angle A1 can be measured along the longitudinal axis of each side arm. Although shown at the same angle A1, each of the first side arm 18 and the second side arm 20 can have a first acute angle with a different value. When the control bar 14 is depressed such that the device 10 is in the Figure 3 position 10A, the first side arm 18 and the second side arm 20 extend at a second acute angle A2 relative to the common plane P of the base 22. The angle A2 can be measured along the longitudinal axis of each side arm. The second acute angle A2 is less than the first acute angle A1. Although shown at the same angle A2, each of the first side arm 18 and the second side arm 20 can have a second acute angle with a different value.

[0179] The material of the device 10 is selected to provide the ability to elastically deform through the described elastic bending and store potential energy, such as elastic energy, to return the device 10 to the stress-free position. Example materials include plastics (e.g., thermoplastics), composite materials, and nylon. Another example material is polyether block amide, such as that available from Arkema Inc. in King of Prussia, Pennsylvania, USA Another example material is glass fiber-reinforced polyamide. An example glass fiber-reinforced polyamide is available for purchase from Arkema Inc. in King of Prussia, Pennsylvania, USA BZM 70TL. This glass fiber-reinforced polyamide has a density of 1.07 grams per cubic centimeter under the ISO 1183 test method, an instantaneous hardness of 75 according to the Shore D standard under the ISO 868 test method, a tensile modulus of 1800 MPa under the ISO 527 test method (samples conditioned at 23 degrees Celsius and 50% relative humidity for 15 days), and a flexural modulus of 1500 MPa under the ISO 178 test method (samples conditioned at 23 degrees Celsius and 50% relative humidity for 15 days).

[0180] In addition, the relevant dimensions and shapes of the device at the joints and at the side arms 18, 20 contribute to the spring-biased properties of the device 10, as well as its ability to elastically deform under a desired load and return to its original stress-free position. The device 10 can be configured to elastically bend under the action of a force of up to 160 N. For example, referring to Figure 1 , each of the first side arm 18 and the second side arm 20 has a thickness T1 that is greater than the width W1 at the respective joints 24A, 24B. The thickness T1 is measured in the front-to-back (longitudinal) direction of the footwear 12. The width W1 is measured in the medial-to-lateral (transverse) direction of the footwear 12. The greater thickness T1 increases the force required to elastically bend the device 10 to the loaded position.

[0181] In addition, each of the side arms 18 and 20 is twisted outward along their respective longitudinal axes 23A, 23B from the joints 24A, 24B at the base to the central segment 16. In other words, as the ridge 64 along the side arm 18 or 20 turns from an upwardly extending ridge to a ridge that partially extends rearwardly at the rear of the central segment 16, the inward-facing surface 60 of the side arms 18, 20 continuously extends to a slightly upward-facing surface 62, as Figure 2 shown in. Similarly, the side surface 66 at the arm 18 or 20 extends into a slightly downward-facing surface 68 below the ridge 64 at the central segment 16, as Figure 1 best shown in. This twist in the side arms 18, 20 helps to facilitate the downward and rearward movement of the central segment 16 during loading by the foot 46.

[0182] The device 10 is also configured to widen when it moves from the stress-free position to the loaded position. When the control bar 14 is depressed, when the first side arm 18 and the second side arm 20 bend apart from each other, this helps to facilitate the insertion of the foot 46 into the flexible upper 38, thereby pulling the upper 38 attached to the inward-facing surface 60 outward. The bending of the device 10 in the loaded position 10A is shown in the Figure 2 plan view of.

[0183] Although the device 10 is thus configured to facilitate foot entry by virtue of its ability to elastically deform and store elastic energy, it is also configured to limit the amount of deformation to prevent plastic deformation. More specifically, the control bar 14 has an extension 70 that extends generally toward the base 22. When the control bar 14 is in the Figure 1 stress-free position in, the extension 70 is spaced apart from the base 22, and when the control bar 14 is depressed and the device is in the loaded position 10A, the extension 70 contacts the base 22. In Figure 3In [description], the extension portion 70 is shown as 70A, where the device 10 is in the loading position 10A. The contact between the extension portion 70 and the base 22 limits further depression of the control bar 14. Optionally, the base 22 may have an extension portion instead of or in addition to the control bar 14, and the extension portion on the base extends towards the control bar 14.

[0184] In Figures 1 to 6 In an embodiment, the control bar 14 and the base 22 have complementary features that dock during depression of the control bar 14 to limit movement of the device. For example, the extension portion 70 docks with the base 22, thereby limiting the depression of the control bar 14 and limiting the tilting of the control bar 14 towards the outer or inner side during loading. More specifically, the base 22 has a recess 72, and when the control bar 14 is depressed and the device 10 elastically deforms to the loading position 10A, the extension portion 70 projects into the recess 72 and contacts the base 22. When in the recess 72, the side protrusions 74 on either side of the recess 72 prevent lateral movement of the extension portion 70. Since the control bar 14 generally descends along an arc when the joints 24A, 24B bend, the extension portion 70 is positioned such that when it descends along such an arc, the extension portion 70 will dock with the base 22 in the recess 72.

[0185] Figure 7 and Figure 8 FIG. [figure number] shows another embodiment of a footwear item 112 having a heel spring device 110. The heel spring device 110 has functions and features similar to those of the heel spring device 10. The joints 124A, 124B have a thickness T2 that is greater than the thickness T1 of the joints 24A, 24B, and thus can provide greater resistance to the depression of the control bar 14, thereby reducing the need for the extension portion 70 to limit bending. The central segment 16 has a hole 145, and the upper 38 has a heel tab 149 that extends through the hole 145 to further secure the upper 38 to the heel of the device 110. After being inserted through the hole 145, the heel tab 149 may be wound around the device 110, may hang loosely, or may be stitched or fastened to the upper 38 or itself to secure the upper 38 to the device 10.

[0186] Figure 9 FIG. [figure number] shows another embodiment of a footwear item 212 having a heel spring device 210 that is secured to the shoe sole layer 234. The heel spring device 210 has functions and features similar to those of the heel spring device 10. The upper is not shown but would be secured to the shoe sole layer 234 and the device 210 as described with respect to the device 10.

[0187] Figure 10Another embodiment of a footwear item 312 is shown. The footwear item 312 has a heel spring device 310 that is secured to a sole structure 334 and an upper 338. The sole structure 334 is a midsole, and the upper 338 has a flexible covering layer with an elastically stretchable material in the heel region. The heel spring device 310 has functions and features similar to those of the heel spring device 10. The heel spring device 310 may include a base 322 similar to the base 22 but passing through the sole structure 334, or the base arm may terminate at the sole structure 334 and be sufficiently secured to the sole structure 334 such that the sole structure serves as the base. The device 310 is integrated into the fastening system of the upper 338 because the device has a loop 339 that is secured to a side arm and serves as an anchor for a fastening cable 343.

[0188] Figures 11 to 14 Another embodiment of a footwear item 412 is shown. The footwear item 412 has a heel spring device 410 that has functions and features similar to those of the heel spring device 10. The heel spring device 410 is secured to a shoe bottom layer 434 and an upper 438. The upper 438 has a flexible covering 442 with an elastically stretchable material in the heel region for receiving and covering a foot supported on the shoe bottom layer 434. For example, the flexible covering 442 can be an elastically stretchable fabric, such as a four-way stretch nylon fabric. A foam collar 435 is secured to the flexible covering 442 and defines a front portion of an ankle opening 439 in the upper 438. The foam collar is stiffer than the elastically stretchable fabric of the flexible covering 442. The collar 435 may include a foam padding 435A. The foam padding 435A in the rear portion of the collar may project inwardly into the ankle opening 439. Since the foam is compressible, this allows the size of the opening to be adjusted according to different ankle girths.

[0189] A central segment of a control bar 414 of the device 410 has a thinning portion 445 where the flexible covering 442 of the upper 438 is stitched to the device 410. As Figure 14 shown, the foam collar 435 is also stitched to the device 410 at the thinning portion 445. As Figure 12 shown, additional thin extensions 441 of the device 410 extend along side arms 418, 420 and are thin enough to allow the upper 438 to be stitched to the device 410 through the thin extensions 441. The stitches 437 passing through the thinning portion 445 and through the extensions 441 are in Figure 13 and Figure 14is shown. The upper 438 is characterized by the absence of a rigid heel stabilizer. The device 410 functions as a heel stabilizer at least in some respects because it helps to keep the wearer's heel properly positioned on top of the heel portion of the sole structure, thereby preventing medial or lateral displacement during use. Similar to the device 10, the device 410 has a ramp surface 450 for facilitating foot entry.

[0190] Figure 15 Another embodiment of a footwear item 512 is shown, which has a heel spring device 510 that has similar functions and features to the heel spring device 10. The heel spring device 510 is secured to the shoe sole layer 534 and the upper 538, and the upper 538 has a flexible covering 542 with an elastically stretchable material in the heel region for receiving and covering the foot supported on the shoe sole layer 534. When the foot is inserted, the covering 542 stretches to the position 542A. For example, the flexible covering 542 can be an elastically stretchable fabric, such as a four-way stretch nylon fabric. The device 510 includes a forwardly extending support 511. The joints of the device 510 are higher than those in other embodiments because they are located on the sides of the upper 538 above the shoe sole layer 534, as shown.

[0191] Figure 16 Another embodiment of a footwear item 612 is shown, which has a heel spring device 610 that has similar functions and features to the heel spring device 10. The heel spring device 610 is secured to the shoe sole layer 634 and the upper 638, and the upper 638 has a flexible covering with an elastically stretchable material in the heel region for receiving and covering the foot supported on the shoe sole layer 634. For example, the flexible covering can be an elastically stretchable fabric, such as a four-way stretch nylon fabric. The shoe sole layer 634 has molded recesses on its inner and outer sides, in which the base of the device 610 and joint portions such as the joint 624B are partially seated.

[0192] Figures 17 to 18 Another embodiment of a footwear item 712 is shown, which includes a heel spring device 710 that has similar functions and features to the heel spring device 10. The heel spring device 710 is embedded in the flexible covering of the upper 738 and is either secured to the shoe sole layer 734 at its base by an adhesive or other means, or simply sandwiched between the insole and the strobel or upper material to reduce the need for adhesive.

[0193] Figure 19Another embodiment of a footwear item 812 is shown, the footwear item 812 including a heel spring device 810 having similar functions and characteristics to the heel spring device 10. The heel spring device 810 is fixed to the shoe sole layer 834 at its base and is fixed to a flexible covering of the upper 838. A heel tab 849 fixed to the upper forms a loop through which the device 810 passes to the rear of the ankle opening, thereby helping to secure the upper 838 to move with the device 810.

[0194] Figures 20 to 22 Another embodiment of a footwear item 912 is shown, the footwear item 912 including a heel spring device 910 having similar functions and characteristics to the heel spring device 10. The heel spring device 910 is fixed to a shoe sole layer (not shown) at its base and is fixed to a flexible covering of the upper 938. The device 910 has a control bar 914 with side arms 918, 920 and has a base 922 connecting the side arms 918, 920 and located below the control bar 914. The base 922 extends rearward from the junctions 924A, 924B of the control bar 914 and the base 922 to serve as a support. The base 922 will be located below the foot receiving space in the upper to which the heel spring device 910 is fixed and may be located below the lasting in the footwear item 912. The base 922 can be fixed to the shoe sole layer by bonding or other means, or can simply be sandwiched between the shoe sole layer and the lasting or upper material to reduce the need for adhesive. When the control bar 914 is depressed, the device 910 widens laterally outward, as shown by the device 910 being in the loaded position 910A.

[0195] Figure 23 An example graph of the vertical force F in Newtons relative to the displacement D in millimeters on the vertical axis is shown, which schematically represents the elastic bending and energy return behavior of any heel spring device shown and described herein. The displacement D is, for example, Figure 3 the difference between the distances D1 and D2. The first example representation of the behavior of the heel spring device is shown by the loading curve 1003 ( Figure 4 placement of the force F on the control bar of the device, the vertical component of which is represented in the figure), followed by the unloaded curve 1002 (behavior when the force F is removed). The second example representation of the behavior of the heel spring device is shown by the loading curve 1005 and the unloaded curve 1004.

[0196] Figures 24 to 25Another embodiment of a footwear item 1012 is shown, which includes a heel spring device 1010 having similar functions and features to the heel spring device 10. The heel spring device 1010 is fixed at its base to a shoe sole layer (not shown) and is fixed to a flexible covering of the upper 1038. The device 1010 has a control bar 1014 with side arms 1018, 1020, and has a base 1022 connecting the side arms 1018, 1020 and located below the control bar 1014. The base 1022 extends rearwardly from the junction of the control bar 1014 and the base 1022 to serve as a support. The base 1022 can be located below the vamp in the footwear item 1012, can be fixed to the shoe sole layer by adhesive bonding or other means, or can simply be sandwiched between the shoe sole layer and the vamp or upper material to reduce the need for adhesive. The side arms 1018, 1020 of the device 1010 are similar to the side arms 918, 920 of the device 910, except that the side arms 918, 920 extend from the base 922 to the central section of the control bar 914 at a gradually decreasing slope, as Figure 21 best shown in, while the side arms 1018, 1020 extend from the base 1022 to the central section of the control bar 1014 at a gradually increasing slope, as Figure 25 best shown in.

[0197] Figures 26 to 27 Another embodiment of a footwear item 1112 is shown, which includes a heel spring device 1110 having similar functions and features to the heel spring device 10. The heel spring device 1110 is fixed at its base to a shoe sole layer (not shown) and is fixed to a flexible covering of the upper 1138. The base 1122 can be located below the vamp in the footwear item 1112, can be fixed to the shoe sole layer by adhesive bonding or other means, or can simply be sandwiched between the shoe sole layer and the vamp or upper material to reduce the need for adhesive. The device 1110 has a control bar 1114 with side arms 1118, 1120, and has a base 1122 connecting the side arms 1118, 1120 and located below the control bar 1114. The first side arm 1118 and the second side arm 1120 each have a Z-shaped configuration, as Figure 27As best shown in [FIG. 0], when they advance from the joints 1124A, 1124B to the central section of the control bar 1114, they first extend backward, then forward, and then backward again. The junction of the backward-extending portion with the forward-extending portions of the side arms 1118, 1120 can be used as an additional junction for elastic bending caused by a downward force acting on the central section of the control bar 1114 during loading of the device 1110. The base 1122 extends backward from the junction of the control bar 1114 and the base 1122 to serve as a support.

[0198] Figures 28 to 29 Another embodiment of a heel spring device 1210 for a footwear item is shown. The heel spring device 1210 has a control bar 1214 that includes an inner arm 1218 and an outer arm 1220. The control bar 1214 is attachable to a flexible footwear upper. A base 1222 extends from the control bar 1214 and supports the control bar 1214. Different from other embodiments of the heel spring devices disclosed herein, the base 1222 extends from the central section of the control bar 1214, and the junction is between a generally vertical portion and a generally horizontal portion of the base 1222.

[0199] Figures 30 to 31 Another embodiment of a heel spring device 1310 for a footwear item is shown. The device 1310 has a control bar 1314 that includes an inner arm 1318 and an outer arm 1320 extending from the central section of the control bar 1314. The control bar 1314 is attachable to a flexible footwear upper. The central section has a hole 1345 for receiving a heel tab of the flexible footwear upper or for stitching the control bar 1314 to the footwear upper. The ends of the side arms 1318, 1320 widen in the longitudinal direction and, together with the shoe sole layer to which they will be attached, serve as the base and junctions 1324A, 1324B of the device 1310.

[0200] Figure 32Another embodiment of a footwear item 1412 is shown, the footwear item 1412 including a heel spring device 1410 having similar functions and features to the heel spring device 10. The heel spring device 1410 has a control bar 1414 that is secured to a flexible covering of the footwear upper 1438. The control bar 1414 includes an inner arm and an outer arm (one side arm 1420 is shown). The device 1410 includes a base (not shown) that connects the side arms and extends through an opening 1436 in the shoe sole layer 1434 and is secured or embedded in the shoe sole layer 1434. The base may be located below the welt in the footwear item 1412, may be secured to the shoe sole layer 1434 by adhesive bonding or other means, or may simply be sandwiched between the shoe sole layer 1434 and the welt or upper material to reduce the need for adhesive. Thus, the shoe sole layer 1434 serves in part as a base and a junction with the control arm 1314.

[0201] Figure 33 Another embodiment of a footwear item 1512 is shown, the footwear item 1512 including a heel spring device 1510 having similar functions and features to the heel spring device 10. The heel spring device 1510 has a control bar 1514 that is stitched to a flexible covering of the footwear upper 1538. The control bar 1514 includes an inner arm and an outer arm (one side arm 1520 is shown). The device 1510 includes a base (not shown) that connects the side arms and extends through an opening in the shoe sole layer 1534 and is embedded in the shoe sole layer 1534 or otherwise secured to the shoe sole layer 1534. The base may be located below the welt in the footwear item 1512, may be secured to the shoe sole layer 1534 by adhesive bonding or other means, or may simply be sandwiched between the shoe sole layer 1534 and the welt or upper material to reduce the need for adhesive. Thus, the shoe sole layer 1534 serves in part as a base for the control arm and a junction 1524 with the control arm.

[0202] Figures 34 to 35 Another embodiment of a heel spring device 1610 for a footwear item is shown. The device 1610 has a control bar 1614 that includes an inner arm 1618 and an outer arm 1620 extending from a central segment 1616 of the control bar 1614. The control bar 1614 may be attached to a flexible footwear upper. The central segment 1616 and the side arms 1618, 1620 have holes 1645 for stitching the device 1610 to the flexible footwear upper behind the ankle opening (such as at the rear collar of the ankle opening) to prevent the heel tab from folding inward in this area during foot insertion. The device 1610 does not have a base. However, the side arms 1618, 1620 may be secured to portions of the upper 1638 near their distal ends, such as Figure 35As shown, a slightly stiffer but elastic flexible portion 1635 in front of the four-way stretch fabric 1642 in the heel region. In this way, the stiffer portion 1635 of the shoe upper effectively serves as the base of the device 1610 and forms joints with the side arms 1618, 1620 to provide an elastic return of the device 1610 to the stress-free position after a downward force is applied during foot insertion.

[0203] Figure 36 Another embodiment of a heel spring device 1710 for a footwear item 1712 as shown in Figures 37 to 38 is shown. The heel spring device 1710 has similar functions and features to the heel spring device 10. The device 1710 has a control bar 1714 which has a central segment 1716, an inner arm 1718 and an outer arm 1720. The device 1710 has a continuous base 1722 that connects the side arms 1718, 1720 and extends forward from the joint of the control bar 1714 with the base 1722.

[0204] As Figure 37 shown, the heel spring device 1710 is fixed to the sole structure 1732 at its base 1722 and is fixed to a flexible covering (shown in dashed lines) of the footwear upper 1738. The upper 1738 defines at least a part of the foot receiving space 1747 and the ankle opening 1739. The base 1722 is located below the foot receiving space 1747, may be located below the welt in the footwear item 1712, may be fixed to the sole structure 1732 by adhesive bonding or other means, or may simply be clamped between the sole structure 1732 and the welt or upper material to reduce the need for adhesive. The base 1722 extends slightly rearward from the joint of the control bar 1714 with the base 1722 and extends forward from the joint with the control bar 1714 to serve as a support. The base 1722 has a forward extending protrusion 1727 located below the foot receiving space adjacent to the inner side 1741 of the footwear upper and a rearward extending protrusion 1729 located below the foot receiving space along the outer side 1743 of the footwear upper.

[0205] Figure 37 The control bar 1714 biased to the stress-free position is shown. Figure 38 The control bar 1714 elastically bending to the loaded position under the applied force, thus widening the ankle opening 1739, is shown. The device 1710 stores elastic energy which causes the control bar 1714 to return to the stress-free position when the applied load is removed.

[0206] Figures 39 to 40An article of footwear 1812 is shown having a heel spring device 1810. The article of footwear 1812 and the heel spring device 1810 are similar in many respects to the article of footwear 1712 and the heel spring device 1710, and like reference numerals are used to refer to like components. The heel spring device 1810 is similar to the heel spring device 1710 in all respects, except that the heel spring device 1810 has a continuous base 1822, and the base 1822 has a main portion 1831 and a protrusion 1833 that extends downwardly from the main portion into a recess 1835 in the foot-facing surface 1837 of the sole structure 1732. The protrusion 1833 is configured to be seated in the recess 1835. The walls of the protrusion 1833 butt against the walls of the sole structure 1732 at the recess 1835, thereby providing stability for the base 1822. Additionally, the protrusion 1833 forms a cavity 1839 in the recess 1835, and the cavity can be used to house various footwear components or accessories, such as electronic accessories.

[0207] Figure 41 Another embodiment of a heel spring device 1910 for the article of footwear 1912 shown in Figures 42 to 43 is shown. The heel spring device 1910 has similar functions and features to the heel spring device 10. The device 1910 has a control bar 1914 with an inner arm 1918 and an outer arm 1920. The device 1910 has a continuous base 1922 that connects the side arms 1918, 1920 and extends forwardly and rearwardly from the junction of the control bar 1914 and the base 1922.

[0208] As Figure 42 shown, the heel spring device 1910 is fixed to the sole structure 1732 at its base 1922 and to a flexible covering (shown in dashed lines) of the footwear upper 1738, both of which are described with reference to Figure 37 The base 1922 is located below the foot receiving space 1747, may be located below the topline in the article of footwear 1912, may be fixed to the sole structure 1732 by adhesive bonding or other means, or may simply be sandwiched between the sole structure 1732 and the topline or upper material to reduce the need for adhesive.

[0209] The inner arm 1918 and the outer arm 1920 each have at least one slot 1980 extending therethrough and, in the illustrated embodiment, have a plurality of slots 1980. The slots 1980 extend through the first side arm 1918 and extend in the longitudinal direction along the longitudinal axis of the inner arm 1918 (i.e., along the length of the side arm 1918). Separate slots 1980 extend through the outer arm 1920 and extend in the longitudinal direction along the longitudinal axis of the outer arm 1920 (i.e., along the length of the side arm 1920). The slots 1980 reduce the thickness of the side arms 1918, 1920 and thus reduce the force required to bend the side arms 1918, 1920. More specifically, with the slots 1980, each side arm is divided into a plurality of slats 1981 at the slots. The slats 1981 act as a plurality of thinner side arms that bend along their lengths in the region of the slots 1980. Figure 42 The control bar 1914 is shown biased to the stress-free position. Figure 43 The control bar 1914 is shown elastically bending to the loaded position under the applied force, widening the ankle opening 1739 and tilting the ankle opening downward and backward as compared to the unloaded position. As Figure 43 shown, in the loaded position, the side arms 1918, 1920 can be configured such that at least a portion of the slots 1980 close, causing the slats 1981 to contact each other, thereby increasing stiffness and resistance to further bending. The device 1910 stores elastic energy that returns the control bar 1914 to the stress-free position when the applied load is removed.

[0210] Figure 44 Shown is another embodiment of the heel spring device 2010 for a footwear item 2012 as Figures 45 to 46 shown. The heel spring device 2010 has similar functions and features to the heel spring device 10. The device 2010 has a control bar 2014 with an inner arm 2018 and an outer arm 2020. The device 2010 has a continuous base 2022 that connects the side arms 2018, 2020 and extends forward and backward from the junction of the control bar 2014 and the base 2022.

[0211] As Figure 45 shown, the heel spring device 2010 is fixed to the sole structure 2032 at its base 2022 and is fixed to a flexible covering of the upper 1738 (shown in dashed lines), both of which are described with reference to Figure 37 this. The base 2022 is located below the foot receiving space 1747, can be located below the welt in the footwear item 2012, can be bonded to the sole structure 2032 by an adhesive or other means, or can simply be sandwiched between the sole structure 2032 and the welt or upper material to reduce the need for adhesive.

[0212] The inner arm 2018 and the outer arm 2020 each have at least one slot 2080 extending therethrough and, in the illustrated embodiment, a plurality of slots 2080. The slots 2080 extend through the inner arm 2018 and are transverse to the longitudinal axis 23A of the inner arm 2018 (i.e., transverse to the length of the side arm 2018). Separate slots 2080 extend through the outer arm 2020 and are transverse to the longitudinal axis 23B of the outer arm 2020 (i.e., transverse to the length of the side arm 2020). The slots 2080 reduce the thickness of the side arms 2018, 2020 and thus reduce the force required to bend the side arms 2018, 2020. More specifically, with the slots 2080, each side arm is divided into a plurality of fingers 2081 at the slots 2080. The fingers 2081 serve to reduce the thickness of the bent portion of the side arms 2018, 2020 to the thickness between the ends 2083 of each slot 2080 and the upper surface 2085 of each side arm 2018, 2020, rather than the entire thickness of the side arm from the upper surface 2085 to the lower surface 2087. The fingers 2081, ends 2083 and surfaces 2085, 2087 are Figure 44 labeled with respect to the outer arm 2020 and apply equally to similar features of the inner arm 2018. Figure 45 The control bar 2014 is shown biased to the stress-free position. Figure 46 The control bar 2014 is shown elastically bent to the loaded position under the applied force, with the ankle opening 1739 widened compared to the unloaded position. As Figure 46 shown, in the loaded position, the side arms 2018, 2020 can be configured such that at least a portion of the slots 2080 close, causing the fingers 2081 to contact each other, thereby increasing stiffness and resistance to further bending. The device 2010 stores elastic energy that returns the control bar 2014 to the stress-free position when the applied load is removed.

[0213] Figures 47 to 48 Another embodiment of a heel spring device 2110 is shown, which has similar functions and features to the heel spring devices of heel spring devices 10 and Figure 27 In Figure 48 the device 2110 is shown in a footwear article 2112 that is fixed to a sole structure 2132 and a flexible covering (shown in dashed lines) of a footwear upper 2138, both the sole structure 2132 and the flexible covering of the footwear upper 2138 being similar to the reference Figure 37The described content. The heel spring device 2110 is similar to the heel spring device 1110 in all respects, except that it has a base 2122 that extends forward and backward from the side arms 1118, 1120 of the control bar 1114, as opposed to the base 1122 that only extends backward.

[0214] Figure 49 An article of footwear 2212 having another embodiment of a heel spring device 2210 is shown. The heel spring device 2210 has similar functions and features to the heel spring device 10. The device 2210 has a control bar 2214 that has an inner arm 2218, an outer arm 2220, and a central segment 2216 that connects the side arms 2218, 2220, and the side arms extend generally downward and forward from the central segment 2216. Similar to that described with respect to device 10 and article of footwear 12, the device 2210 is secured to a flexible footwear upper 2238 and a sole structure 2232.

[0215] When the footwear 2212 is in Figure 49 the position of being rested on the sole structure, the pin 2290 is generally horizontally disposed. The pin 2290 extends laterally through the sole structure 2232 and serves as a continuous base and is connected to the side arms 2218, 2220 at a first joint and a second joint. The pin 2290 is connected to the inner arm 2218 and the outer arm 2220 at the docking of the inner arm 2218 and the outer arm 2220 with the sole structure 2232. The pin 2290 establishes a pivot axis along the length of the pin 2290 (transverse to the sole structure 2232) about which the control arm 2214 pivots between an unstressed position and a loaded position. A biasing element such as a torsion spring 2291 is wound around the pin 2290, one end of which is fixed to the pin 2290 and the other end of which is fixed to the sole structure 2232. For example, the pin 2290 has a first end 2292 that is fixed at the inner side surface of the sole structure and a second end 2294 that is fixed to the pin 2290. The control bar 2214 pivots to the loaded position to wind the torsion spring 2291, thereby storing potential energy.

[0216] The control bar 2214 is biased to the unstressed position shown by the solid line. When the device 2210 pivots to the loaded position under the action of an applied force, the control bar 1714 is shown as 2214A in dashed lines, and in this loaded position, the device is indicated as 2210A. The ankle opening 2739 widens in the loaded position and can tilt downward and backward relative to the unloaded position because the flexible covering 2442 (also referred to as the flexible covering layer) of the upper 2238 is fixed to the control bar 2214 and moves downward together with the control bar 2214. The spring 2291 stores spring energy that returns the control bar 2214 to the unstressed position when the applied load is removed.

[0217] Figures 50 to 51 FIG. 2312 shows a footwear item 2312 having a heel spring device 2310. The heel spring device 2310 has functions and features similar to those of the heel spring device 10. The device 2310 has a control bar 2314, and the control bar 2314 has an inner arm 2318 and an outer arm (not shown, but a mirror image of the inner arm 2318). The device 2310 has a continuous base 2322, and the continuous base 2322 connects the side arms and extends forward and backward from the junction of the control bar 2314 with the base 2322 similar to the base 22 in Figure 1 .

[0218] As Figures 50 to 51 shown, the heel spring device 2310 is fixed to the sole structure 32 at its base 2322 and to a flexible covering of the footwear upper 38, both of which are described with reference to Figures 5 to 6 .

[0219] The control bar 2314 has at least one slot 2380 that extends continuously from the first side arm 2318, across the central segment 2316, to the second side arm, and extends through the first side arm 2318, across the central segment 2316, and through the second side arm (a mirror image of the slot as shown). In the illustrated embodiment, there are a plurality of slots 2380. The same slot 2380 that extends through the first side arm 2318 and extends longitudinally along the longitudinal axis of the first side arm 2318 (i.e., along the length of the side arm 2318) also extends through the second side arm and extends longitudinally along the longitudinal axis of the second side arm (i.e., along the length of the second side arm). The slots 2380 reduce the thickness of the side arms and thus reduce the force required to bend the side arms. More specifically, by the slots 2380, each side arm is divided into a plurality of slats 2381 at the slots. The slats 2381 act as a plurality of thinner side arms that bend along their lengths in the region of the slots 2380.

[0220] Figure 50 FIG. 2314 shows the control bar 2314 biased to the stress-free position. Figure 51 FIG. 2315 shows the control bar 2314 elastically bent to the loaded position under the applied force, which widens the ankle opening 39 and tilts the ankle opening downward and backward compared to the unloaded position. As Figure 51As shown, in the loaded position, the side arm 2318 (while the second side arm is not shown) can be configured such that at least a portion of the slot 2380 is closed, causing the slats 2381 to contact each other, thereby increasing stiffness. However, when the slats 2381 come into contact due to the closing of the slot 2380, the slats 2381 can slide against each other. Compared to a control bar similar to the control bar 2314 but without slots, the sliding allows further bending to continue with reduced stiffness. Figure 51 Slight staggering is shown at the rear of the stacked slats 2381, indicating that they have slid relative to each other in the case of slot closure. The device 2310 stores elastic energy, which returns the control bar 2314 to the stress-free position when the applied load is removed.

[0221] Figure 52 An article of footwear 2412 is shown having a heel spring device 2410. The heel spring device 2410 has similar functions and features to the heel spring device 10. The device 2410 has a control bar 2414, the control bar 2414 having an inner arm 18 and an outer arm 20, and a central section 16 connecting the side arms 18, 20, and the side arms extending generally downward and forward from the central section 16. The device 2410 has a continuous base 22 as described Figure 1 and is fixed to the flexible footwear upper 2438 and the sole structure 2432, similar to as described with respect to the device 10.

[0222] The central section 16 has a hole 2445, and the upper 2438 has a heel tab 2449 that extends through the hole 2445 to further secure the upper 2438 to the device 2410. The central section 16 also has an extension 2470 that extends downward from the central section 16 and can limit the bending of the device 10 through interference with the base 22, similar to as described with respect to the extension 70. The extension 2470 has a fastener opening 2451 that receives a stud (not shown) and can be used to secure the heel tab 2449 to the extension 2470 using a fastener such as a stud, snap, or button. Optionally or additionally, the heel tab 2449 can be fixed to the mounting surface 2472 of the extension 2470 with an adhesive or other means.

[0223] Figure 53An article of footwear 2512 is shown having a heel spring device 2510. The heel spring device 2510 has a rear control bar 2514, the rear control bar 2514 having an inner arm 2518 fixed to the inner side of the footwear and an outer arm (not shown) that is a mirror image of the inner arm 2518 but fixed to the outer side of the footwear 2512. The rear control bar 2514 also has a central segment 2516 connecting the inner and outer arms, and the side arms extend generally downwardly and forwardly from the central segment. The device has a front bar 2515, the front bar 2515 also having inner and outer arms and a central segment 2516 connecting the inner and outer arms. A flexible footwear upper 2538 is secured to the central segment 2516 of the front bar 2515, is secured to the central segment 2416 of the rear control bar 2514, and is secured to the inner and outer arms of the rear control bar 2514 and the front bar 2515. Thus, the relative positions of the central segments 2416, 2516 determine the fore-aft expanse of the ankle opening 2539 formed by the upper 2538.

[0224] The bars 2514 and 2515 may be anchored at their ends to the sole structure 2532. The bars 2514, 2515 are positioned to cross each other on both the inner and outer sides, and are pivotally fixed to each other at a connection 2590 (one shown) on the outer and inner sides where they cross. The connection 2590 may be a pin joint. A torsion spring 2591 may be operatively fixed at the connection. The upper portions of the bars 2514, 2515 may be elastically bent such that when a force (such as the force of a foot entering the upper 2538) is applied to the central segment 2416, the central segments 2416 and 2516 may move in a direction spaced apart from each other. The positions of the central segments 2416, 2516 under a loading action are shown in phantom as 2416A, 2516A. The device 2510 stores potential energy, such as elastic energy and / or spring energy, that causes the rear control bar 2514 to return to a stress-free position when the applied force is removed (i.e., after the foot has slipped into the foot receiving cavity of the upper 2538).

[0225] Figure 54 An article of footwear 2612 is shown having another embodiment of a heel spring device 2610. The heel spring device 2610 has similar functions and characteristics to the heel spring device 2310. The device 2610 has a control bar 2614, the control bar 2614 having a series of slats 2681, and a plurality of slots 2680, as Figure 55 best shown in. Each slat 2681 has a central segment 2616, an inner arm 2618 (at Figure 57best shown) and outer arm 2620. In one or more embodiments, the outer arm 2620 and the inner arm 2618 may be configured to be mirror images of each other. The device 2610 has a continuous base 2622 that is located below the control bar 2614, and the continuous base 2622 connects the side arms 2618, 2620 and extends forward and backward from the junction of the control bar 2614 with a base 2622 similar to the base 22 of Figure 1 As can be seen from Figure 57 and Figure 58 The device 2610 has a concave inner surface 2611 that has a concavity in both the medial-lateral direction and the vertical direction.

[0226] The footwear item 2612 includes a sole structure 2632 and an upper 38 having a flexible covering (which is described with reference to Figures 5 The heel spring device 2610 is fixed to the flexible covering of the footwear upper 38 via a strap 2633 that has a chamber 2635, as described with reference to ​

[0227] As ​ shown, the heel spring device 2610 is also fixed to the sole structure 2632 at the base 2622 of the heel spring device 2610. As ​ shown, the outer surface of the base 2622 of the device 2610 has a peripheral recess 2622A that extends from the lower edge 2622B of the base 2622. The peripheral recess 2622A is shown in ​ , ​ on the outer side surface of the base 2622 and extends around the inner side surface of the base 2622 in a mirror image of the outer side surface. The shape and size of the peripheral recess 2622A shown in ​ are designed to receive a flange 2632A of the sole structure 2632. The flange 2632A may be adhered or heat bonded to the base 2622 in the peripheral recess 2622A. The sole structure 2632 thus provides lateral support for the base 2622.

[0228] The control bar 2614 is biased to the unloaded position shown in ​ and elastically bends under the action of the applied force F to ​ ​At the loading position shown, each central segment 2616 is closer to the base 2622 at this loading position than at the unloaded position, thus storing potential energy which, when the applied force F is removed, causes the control bar 2614 to return to the unloaded position. The control bar 2614 and the base 2622 are configured as full-elliptical leaf springs. The device 2610 can be elastically bendable nylon or another elastically bendable material. The central segment 2616 is spaced apart from the base 2622, and the device 2610 is characterized in that: at the rear of the joint 2624A( ​ as represented in and the mirror image of the joint 2624B) between the inner arm 2618 and the base 2622 and at the rear of the joint 2624B between the outer arm 2620 and the base 2622, there is no rigid heel stabilizer between the central segment 2616 and the base 2622. The device 2610 functions as a heel stabilizer at least in some respects because it helps to keep the wearer's heel in the proper position at the top of the heel portion of the sole structure, thus preventing medial or lateral displacement during use.

[0229] As ​ shown, the slot 2680 reduces the amount of material between the uppermost slat 2681B and the lowermost slat 2681A in the slats at the side arms, and thus reduces the force required to bend the side arms. More specifically, through the slot 2680, the slats 2681 function as a plurality of thinner side arms that bend along their lengths in the region of the slot 2680. The lowermost slat 2681A in the slats closest to the base 2622 at the central segment 2616 is shorter from its inner end 2682A to its outer end 2683A than the uppermost slat 2681B in the slats from its inner end 2682B to its outer end 2683B, where the uppermost slat 2681B is the farthest from the base 2622. The inner ends 2682A, 2682B are represented in ​ and are the mirror images of the outer ends 2683A, 2683B shown in ​ .

[0230] In one or more embodiments, the lowermost slat 2681A is thinner than the uppermost slat 2681B at any position along their lengths between the inner and outer ends, which is in ​This is evident in an exemplary embodiment by comparing the thickness T3 of the lowermost slat 2681A and the thickness T4 of the uppermost slat 2681B. In other words, although the thickness of slat 2681A can vary from its inner end to its outer end, and the thickness of slat 2681B can vary from its inner end to its outer end, at any given position between the inner and outer ends of slat 2681A, the thickness of slat 2681A will be less than the thickness of slat 2681B along a line perpendicular to the longitudinal axis of slat 2681A.

[0231] When the control strip 2614 is in ​ the unloaded position, the slats 2681 are spaced apart from each other by the slots 2680. The slots 2680 are closed between the slats 2681 at at least some portions of the slots 2680 such that adjacent central segments 2616 ​ contact each other in the loaded position. In the illustrated embodiment, the slots 2680 are closed at the central segments 2616 in the loaded position, but may remain open at the side arms 2618, 2620. The slots 2680 are parallel to each other, and the outer sides 2644 of the slats 2681 are ​ flush with each other in the unloaded position shown. Compared to the case where the control strip 2614 has the same total thickness as the plurality of slats 2681 from the uppermost slat 2681B to the lowermost slat 2681A, the slots 2680 enable the control strip 2614 to bend with less resistance (i.e., lower stiffness). In a typical embodiment corresponding to ​ , when the slats 2681 come into contact with each other due to the closing of the slots 2680, the slats 2681 can slide against each other (but not past). Compared to a control strip constructed in the manner of the control strip 2614 but without slots, the sliding enables further bending to continue with reduced stiffness. ​ A slight staggering of the rear portions of the stacked slats 2681 is shown to indicate their sliding relative to each other when the slots 2680 are closed.

[0232] ​ It is shown that the control strip 2614 is biased to the stress-free (i.e., unloaded) position. ​ It is shown that the control strip 2614 is elastically bent to the loaded position under the applied force F (e.g., due to the force of a foot slipping into a footwear item), and when the upper 38 moves with the control strip 2614 in the heel region, this loaded position will cause ​The ankle opening 39 of the shoe upper 38 widens. When a force F is applied, the heel region of the shoe upper 38 behind the ankle opening 39 moves with the central section 2616 of the control bar closer to the base 2622, causing the ankle opening 39 to expand or at least change the position of the ankle opening such that the ankle opening 39 can tilt downward and backward relative to the unloaded position, and the foot can enter from the rear downward and forward rather than just downward, as by ​ comparing the position of the ankle opening 39 in ​ with the position of the ankle opening 39 in

[0233] is best shown. ​ , the lowermost slat 2681A has an extension 2684 extending from the lower edge 2685 of the central section 2616. The extension 2684 extends at least partially downward from the central section 2616 and at least partially toward the base 2622. As ​ shown, when the control arm 2614 is in the unloaded position, the extension 2684 extends downward and backward. In ​ the loaded position, the extension points more straight downward than in the unloaded position. Additionally, the control bar 2614 and the extension 2684 are configured to move away from the base 2622 such that when the control arm 2614 is in the loaded position, the extension is behind the base 2622. In such an embodiment, no recess is required in the base 2622.

[0234] Referring to ​ , ​ and ​, the strap 2633 has a proximal end 2633A that is stitched, integrally formed, or otherwise connected to the upper 38 near the ankle opening 39 at the rear of the upper 38. The strap 2633 has a chamber 2635 at its distal end 2633B. The chamber 2635 can be formed, for example, by folding the strap 2633 over itself at the distal end 2633B and stitching the folded portion to the remainder of the strap 2633. The strap 2633 can extend downward from the upper 38. The strap 2633 is placed above and behind the control strap 2614, and then the extension 2684 is disposed in the chamber 2635, where the strap 2633 covers the central segment 2616. Thus, the extension 2684 and the strap 2633 are used to operably connect the upper 38 to the control strap 2614 such that the portion of the upper 38 behind the ankle opening 39 will move downward with the control strap 2614 to the loaded position, facilitating the foot to pass through the ankle opening 39 into the foot receiving cavity of the upper 38, and then when the force F is removed, move upward with the control strap back to the unloaded position, thereby placing the upper 38 around the rear of the foot that has been inserted into the foot receiving cavity.

[0235] ​ An article of footwear 2712 having a heel spring device 2710 is shown. Like reference numerals are used to refer to the same components as those described with respect to the article of footwear 2612 and the heel spring device 2610. The heel spring device 2710 has similar functions and features as the heel spring device 2610. The device 2710 has a control strap 2714 that has a series of slats 2781 and a plurality of slots 2780 best shown in ​ . Each slat 2781 has a central segment 2716, an inner arm 2718 (best shown in ​ ) and an outer arm 2720 best shown in ​ . The outer arm 2720 and the inner arm 2718 are mirror images of each other. The device 2710 has a continuous base 2622, as described with reference to ​ and ​ , that is located below the control strap 2714, connects the side arms, and extends rearward from the junction of the control strap 2714 and the base 2622. As can be clearly seen from ​ and ​ , the device 2710 has a concave inner surface 2711 that is concave in both the medial-lateral direction and the vertical direction.

[0236] The slot 2780 reduces the amount of material between the uppermost slat 2781B and the lowermost slat 2781A in the slats at the side arms, and thus reduces the amount of force required to bend the side arms via the force F applied to the central segment 2616. More specifically, due to the slot 2780, the slats 2781 act as multiple thinner side arms that bend along their lengths in the region of the slot 2780. As ​ and ​ shown, the lowermost slat 2781A in the slats 2781 closest to the base 2622 is shorter from its inner end 2782A to its outer end 2783A than the uppermost slat 2781B in the slats 2681 from its inner end 2782B to its outer end 2783B, where the uppermost slat 2781B is the farthest from the base 2622. The inner ends 2782A, 2782B are represented in ​ and are mirror images of the outer ends 2783A, 2783B.

[0237] At any point along the lowermost slat 2781A, the lowermost slat 2781A is thinner at the corresponding point (e.g., at the point directly above the point along the lowermost slat) than any of the other slats, as best shown in ​ . The thickness of the slat is measured along its longitudinal axis. Although the thickness of the slat 2781A may vary along its longitudinal axis from its inner end to its outer end, and the thickness of the slat 2781B may vary along its longitudinal axis from its inner end to its outer end, at any given point between the inner end and the outer end of the slat 2781A, the thickness of the slat 2781A will be less than the thickness of the slat 2781B at the point directly above the point along the slat 2781A.

[0238] When the control bar 2714 is in the ​ unloaded position, the slats 2781 are spaced apart from each other by the slot 2780. The heel spring device 2710 includes an elastic insert 2790 that at least partially fills the slot 2780. The elastic insert 2790 may include an elastically compressible material such as at least one of rubber or thermoplastic polyurethane, and may be a foam, but is not limited to these materials. In the illustrated embodiment, the elastic insert 2790 is a thermoplastic polyurethane foam that provides compressive stiffness and elastic resiliency. As best shown in ​ , the elastic insert 2790 includes a bushing 2791 having spaced-apart protrusions 2792 extending outwardly on the outer surface 2793 of the bushing 2791. As Figure 65As best shown in, the bushing 2791 is configured to extend along the inner side of the slats 2781 from the uppermost slat 2781B of the slats 2781 to the lower perimeter of the base 2622. The outer perimeter of the bushing 2791 coincides with the outer perimeters of the slats 2781 and the base 2622.

[0239] Spaced protrusions 2792 extend from the bushing 2791 into the slots 2780 between the slats 2781. When the device 2710 is in Figure 61 and Figure 62A the unloaded position, the spaced protrusions 2792 are shaped and sized to completely fill the slots 2780. In other embodiments, the spaced protrusions 2792 may be narrower than the slots 2780. The spaced protrusions 2792 may be flush with the outer surface of the slats 2781 or may extend outwardly beyond the outer surface of the slats 2781. The slats 2781 and the base 2622 may be referred to as a cage for holding the insert 2790.

[0240] When a downward force F is applied to the control bar 2714, the slots 2780 partially close between the slats 2781, thereby moving the control bar 2714 to Figure 62B the loaded position such that the adjacent central segments 2716 move closer to each other and the protrusions 2792 are partially compressed between the slats 2781. The bushing 2791 is also compressed as the control bar 2714 moves downward. Since the bushing 2791 and / or the slats 2781 are operatively fixed to the heel portion of the flexible covering of the shoe upper 38 behind the ankle opening 39, the shoe upper 38 moves downward with the bushing 2791 and the control bar 2714 to the loaded position. Thus, the amount of force required to move the device 2710 from the unloaded position to the loaded position depends on the bending stiffness of the control arm 2714 and the compression stiffness of the resilient insert 2790 in the slots 2780. The compression stiffness of the insert 2790 is less than the bending stiffness of the slats 2781, and thus the control bar 2714 can be bent with a smaller force F compared to having the same total thickness as the plurality of slats 2781 from the uppermost slat 2781B to the lowermost slat 2781A (i.e., if the control bar 2714 had no slats).

[0241] The footwear item 2712 includes a sole structure 2632 and a footwear upper 38 having a flexible covering. The heel spring device 2710 is secured to the flexible covering of the footwear upper 38 by adhesive, stitching, heat bonding, or other means such that the rear portion of the upper 38 behind the ankle opening 39 moves with the heel spring device 2710. The heel spring device 2710 is also secured to the sole structure 2632 at its base 2622 by a flange 2632A of the sole structure 2632 fixed in a peripheral recess 2622A.

[0242] The control bar 2714 is biased to Figure 62A the unloaded position shown in and elastically bent to the Figure 62B loaded position shown in under the action of the applied force F. In the loaded position, since the arms 2718, 2720 are bent and store potential energy, each central segment 2716 is closer to the base 2622 than in the unloaded position, and this potential energy returns the control bar 2714 to the unloaded position when the applied force F is removed. The control bar 2714 and the base 2622 are configured as full-elliptical leaf springs. The slat 2781 and the base 2622 can be made of nylon or other elastically bendable materials.

[0243] Figure 62A It is shown that the control bar 2714 is biased to the stress-free (i.e., unloaded) position. Figure 62B It is shown that the control bar 2714 is elastically bent to the loaded position under the action of the applied force F (such as the force when a foot slips into a footwear item), and when the upper 38 moves with the control bar 2714 in the heel region, this loaded position will cause Figure 61 the ankle opening 39 of the upper 38 to widen compared to the unloaded position. When the force F is applied, the heel region of the upper 38 behind the ankle opening 39 moves with the central segment 2716 of the slat 2781 closer to the base 2622, so that the ankle opening 39 is enlarged or at least repositioned by lowering the upper 38 behind the ankle opening 39, such that the ankle opening 39 can be tilted downward and backward relative to the unloaded position and can be used for a foot moving downward and forward from the rear to enter.

[0244] The slat 2781 and the base 2622 can be injection molded. Once molded, the slat 2781 and the base 2622 are a single, integral component. The material of the foam insert 2790 can then be injected into the mold cavity containing the molded slat 2781 and base 2622. Figure 66 It is shown the holes 2794 (only some of which are numbered), where pins hold the slat 2781 and the base 2622 against the surface of the mold while the material of the insert 2790 is being injected. The insert 2790 is molded around the rib 2795 of the base 2622 near the junction of the slat 2781 and the base 2622, as indicated by the slot 2796 in the Figure 64 insert 2790.

[0245] Figure 67FIG. 2712A shows another embodiment of a footwear item 2712A having a heel spring assembly 2710A. The heel spring assembly 2710A is similar to the heel spring assembly 2710 in all respects, except that the insert 2790 has a protrusion 2792A that is configured as a pleat that extends outwardly from the inner side of the slats 2781 and fills the slots between the slats 2781. The slats 2781 and the base 2622 may be formed of a semi-rigid or rigid thermoplastic polyurethane, while the insert 2790 having the protrusion 2792A may be formed of a thermoplastic polyurethane that is softer relative to the slats 2781 and the base 2622.

[0246] Figure 68 FIG. 2812 shows another embodiment of a footwear item 2812 having a heel spring assembly 2810. Like reference numerals are used to refer to components that are the same as those described with respect to the footwear item 2612 and the heel spring assembly 2610. The heel spring assembly 2810 has a similar function to the heel spring assembly 2710, but includes an elastomeric corrugated body 2815 that includes a central segment 2816, an inner arm 2818 that extends downwardly and forwardly from the central segment 2816 (best shown in Figure 69 ), and an outer arm 2820 that extends downwardly and forwardly from the central segment 2816 (best shown in Figure 68 ). The corrugated body 2815 includes alternating ridges 2881 and grooves 2880 that extend in the longitudinal direction along the inner arm 2818, the central segment 2816, and the outer arm 2820. As can be seen clearly from Figure 70 and Figure 71A , the device 2810 has a concave shape on the inner surface in both the medial-lateral direction and the vertical direction.

[0247] The corrugated body 2815 is biased to the unloaded position shown in Figure 68 , Figure 69 , Figure 70 and Figure 71A . The corrugated body 2815 is compressed to the loaded position shown in Figure 71B under the action of the applied force F. In the loaded position, the corrugated body 2815 compresses (e.g., by folding) such that adjacent ridges in the alternating ridges 2881 are closer to each other than in the unloaded position, particularly at the central segment 2816), thereby storing elastic energy that causes the corrugated body 2815 to return to the unloaded position when the applied force F is removed. The upper 38 moves with the central segment 2816 such that when the heel spring assembly 2810 is in the loaded position, the ankle opening 39 can tilt downwardly and rearwardly relative to the unloaded position.

[0248] AsFigure 68 As shown, the ridges 2881A and grooves 2880A of the first group extend from the inner arm 2818 to the outer arm 2820, while the ridges 2881B and grooves 2880B of the second group extend only along the central segment 2816. The first and second groups are configured such that the ridges and grooves can follow the contour of the upper 38 and extend along the entire portion of the upper 38 behind the ankle opening 39, while still allowing some of the grooves and ridges (i.e., the first group) to extend downward and forward.

[0249] Referring Figure 69 to, the device 2810 may include an upper flange 2823 extending along the upper edge 2825 of the corrugated body 2815 at the central segment 2816, and also include a lower flange 2822 extending along the lower edge 2827 of the corrugated body 2815 at the inner arm 2818, central segment 2816, and outer arm 2820.

[0250] The lower flange 2822 is also referred to as a base. The sole structure 2632 is fixed to the lower flange 2822 by adhesive, thermal bonding, or other means such that the sole structure 2632 is generally located below the upper 38 and the heel spring device 2810, as Figure 68 shown. As Figure 69 best shown in, the outer surface of the base 2822 has a peripheral recess 2822A extending from the lower edge 2822B of the base 2822. The sole structure 2632 has a flange 2632A configured to fit into the peripheral recess 2822A. The flange 2632A of the sole structure 2632 provides lateral support for the heel spring device 2810.

[0251] As shown by the stitches 2829 in Figure 68 , the upper flange 2823 is stitched to the upper 38 behind the ankle opening 39. The upper flange 2823 may alternatively be adhered or thermally bonded to the upper 38. The connection of the upper flange 2823 of the heel spring device 2810 to the upper 38 enables the upper 38 to move with the heel spring device 2810 between a loaded position and an unloaded position.

[0252] The ridges 2881 and grooves 2880 of the corrugated body 2815 may also be referred to as pleated members. The ridges 2881 are the convex pleats of the pleated members, while the grooves 2880 are the concave folds of the pleated members. The device 2810 is a single-piece, integral component including the corrugated body 2815 and flanges 2822, 2823. The device 2810 may be injection molded from an elastically deformable material (such as at least one of rubber or thermoplastic polyurethane), and may be an elastic foam (such as a polymer foam material, etc.), but is not limited to these materials.

[0253] Figure 72 Another embodiment of the heel spring device 2910 within the scope of the present teachings is shown. As described with respect to the heel spring device 2710, the heel spring device 2910 has spaced-apart slats 2781 and a base 2622 and is biased to Figure 72 the unloaded position shown therein, but elastically bends to a loaded position (not shown) in response to an applied load, which helps to open the ankle opening of the upper to facilitate foot entry as described with respect to the heel spring device 2710. The heel spring device 2910 includes a discrete elastic insert 2990 that is disposed in the slot 2780, but only along a portion of the central segment 2716 (e.g., not in the slots of the side arms). A strip 2991 adheres to or otherwise connects to the insert 2990 and the slat 2781 to hold the insert 2990 in place within the slot 2780. Optionally, the strip 2991 can be an integral part of the elastic insert 2990 such that the elastic insert 2990 is integrated as a single unitary component.

[0254] Figure 73 Another embodiment of the heel spring device 3010 is shown. As described with respect to the heel spring device 2710, the heel spring device 3010 has spaced-apart slats 2781 and a base 2622 and is biased to Figure 73 the unloaded position shown therein, but elastically bends to a loaded position (not shown), which helps to open the ankle opening of the upper to facilitate foot entry as described with respect to the heel spring device 2710. The heel spring device 3010 has a pair of intermediate slats 3083 that are arranged as an oval spring between the base 2622 and one of the intermediate slats of the slats 2781 and are respectively connected to the base 2622 and the intermediate slat 2781. The heel spring device 3010 also has a pair of intermediate slats 3085 that are arranged as an oval spring between the topmost slat of the slats 2781 and one of the intermediate slats and are respectively connected to the topmost slat and the intermediate slat. The pairs of intermediate slats 3083, 3085 provide additional resistance to bending and store elastic energy to return the heel spring device 3010 to the unloaded position when the applied load is removed. The arrangement of the slats 2781 and the intermediate slats 3083, 3085 can be referred to as a lattice.

[0255] Figure 74An article of footwear 3112 is shown with a heel spring device 3110. Like reference numbers are used to refer to like components as described with respect to the article of footwear 2612 and the heel spring device 2610. The heel spring device 3110 has a similar function to the heel spring device 2610, but includes a fluid-filled bladder 3115 that includes a central segment 3116, a medial arm 3118 that extends downwardly and forwardly from the central segment 3116 (shown in Figure 75 ), and a lateral arm 3120 that extends downwardly and forwardly from the central segment 3116. The sole structure 2632 is secured to the lower flange 3122 of the bladder element 3115 by adhesive, thermal bonding, or other means such that the sole structure 2632 is generally located below the upper 38 and the heel spring device 3110, as Figure 74 shown in.

[0256] Applying a downward force F on the central segment 3116 moves the bladder element 3115 from an unloaded position ( Figure 77 ) to a loaded position ( Figure 78 ). The unloaded position is also referred to as the extended position, while the loaded position is also referred to as the collapsed or compressed position. The central segment 3116 may be referred to as a control bar.

[0257] The bladder element 3115 may be thermoformed from a first polymer sheet 3117 and a second polymer sheet 3119 ( Figure 76 shown best in and also referred to as the inner sheet and the outer sheet, or the inner layer and the outer layer, respectively). Optionally, the bladder element 3115 may be blow molded from a preformed polymer material. The bladder element 3115 may be formed from any of a variety of polymer materials that hold a fluid at a predetermined pressure, including a fluid that is a gas (such as air, nitrogen, or other gas). As used herein, "fluid" includes a gas, which includes air, an inert gas such as nitrogen, or other gas. Thus, "fluid-filled" includes "gas-filled".

[0258] For example, the bladder element 3115 can be a TPU material, polyurethane, polycarbamate, polyester, polyester polycarbamate, and / or polyether polycarbamate. Additionally, in one embodiment, the bladder element 3115 can be formed from a sheet having different material layers. The sheets 3117, 3119 can be a laminated film formed from a film having one or more first layers, the one or more first layers including a thermoplastic polyurethane layer and alternating with one or more second layers, the one or more second layers also referred to herein as a barrier layer, gas barrier polymer, or gas barrier. The second layer can include a copolymer of ethylene and vinyl alcohol (EVOH), as disclosed in U.S. Patent No. 6,082,025 to Bonk et al., the copolymer of ethylene and vinyl alcohol being impermeable to the pressurized fluid contained therein, the entire contents of U.S. Patent No. 6,082,025 being incorporated herein by reference. The first layer can be arranged to form the outer surface of the polymer sheet. That is, the outermost first layer can be the outer surface of the bladder element 3115. As disclosed in U.S. Patents Nos. 5,713,141 and 5,952,065 to Mitchell et al., the bladder element 3115 can also be formed from a material including alternating layers of thermoplastic polyurethane and ethylene-vinyl alcohol copolymer. Optionally, the layer can include ethylene-vinyl alcohol copolymer, thermoplastic polyurethane, and regrind material of ethylene-vinyl alcohol copolymer and thermoplastic polyurethane. The sheets 3117, 3119 can have alternating layers of thermoplastic polyurethane (TPU) and gas barrier material. In the illustrated embodiment, the sheets 3117, 3119 are transparent.

[0259] The sheets 3117, 3119 are joined to each other at the perimeter of the bladder element 3115 (such as at the upper flange 3123 and the lower flange 3122, also referred to as the base). The lower flange 3122 is continuous and connects and supports the inner arms 3118, the central segment 3116, and the outer arms 3120. The sheets 3117, 3119 are also joined to each other at a variety of intermediate joining locations 3124 (referred to as webbing). As Figure 74 shown, the upper flange 3123 is thermally bonded, adhered, or otherwise fixed to the shoe upper 38 behind the ankle opening 39. The shoe upper 38 can also be fixed to the inner surface of the first polymer sheet 3117 between the upper flange 3123 and the lower flange 3122. The heel spring device 3110 enables the shoe upper 38 to move between a loaded position and an unloaded position together with the heel spring device 3110 via the connection of the upper flange 3123 to the shoe upper 38. More specifically, the shoe upper 38 moves with the central segment 3116 such that when the heel spring device 3110 is in the loaded position, the ankle opening 39 can tilt downward and backward relative to the unloaded position, enabling the foot to enter without the use of hands.

[0260] The bonding sheets 3117, 3119 form fluid-sealed and may be pressurized or non-pressurized multiple fluid-filled internal cavities 3181A, 3181B, 3181C, 3183A and 3183B. In the illustrated embodiment, the fluid-filled internal cavities 3181A, 3181B, 3181C, 3183A and 3183B are at the ambient pressure of the environment where the fluid-filled cavities are sealed. Optionally, the fluid-filled internal cavities 3181A, 3181B, 3181C, 3183A and 3183B can be pressurized by introducing fluid into the cavities through one or more inflation ports (not shown) that are subsequently sealed.

[0261] In the illustrated embodiment, each of the fluid-filled internal cavities 3181A, 3181B and 3181C is generally tubular and extends in the longitudinal direction along the inner arm 3118, the central segment 3116 and the outer arm 3120. In some embodiments, the cavities 3181A, 3181B, 3181C extend only along the central segment 3116. The cavities 3181A, 3181B, 3181C can be referred to as elongated cavities or tubular cavities. Optionally, fluid-filled cavities of other shapes can extend along the central segment 3116 and can also extend along one or both of the inner arm and the outer arm. For example, multiple discrete cavities are shaped as tubes shorter than the cavities 3181A, 3181B, 3181C or have other shapes, can extend along the central segment 3116, and can be fluidly interconnected with each other through channels formed by the sheets.

[0262] The tubular cavities 3181A, 3181B and 3181C are connected and in fluid communication with the fluid-filled internal cavities 3183A, 3183B, which can be referred to as an inner reservoir 3183A and an outer reservoir 3183B. In this way, the tubular cavities 3181A, 3181B and 3181C are indirectly in fluid communication with each other via the reservoirs 3183A, 3183B. In some embodiments, channels can also be provided that extend directly between adjacent tubular cavities 3181A, 3181B and 3181C such that the tubular cavities 3181A, 3181B, 3181C are in direct fluid communication with each other. In some embodiments, only one of the reservoirs 3183A, 3183B is provided, or no reservoir is provided, and the tubular cavities 3181A, 3181B and 3181C simply terminate at the side arms without a reservoir. In other embodiments, each tubular cavity can have its own separate reservoir on one or two side arms. The reservoirs 3183A, 3183B are formed by a first polymer sheet 3117 and a second polymer sheet 3119 at the inner and outer ends of the tubular cavities 3181A, 3181B and 3181C respectively. As can be seen from Figures 74 to 75As can be clearly seen, the device 3110 has a concave shape on the inner surface of the first polymer sheet in both the inner-outer direction and the vertical direction.

[0263] The formed sheets 3117, 3119 having internal cavities 3181A, 3181B, 3181C, 3183A, 3183B bias the heel spring device 3110 to the Figures 74 to 77 unloaded position shown in. The heel spring device 3110 is compressed to the Figure 78 loaded position shown in under the action of the applied force F, thereby storing elastic energy. For example, the applied force F can be the force of the foot when the foot is inserted into the ankle opening 39 of the footwear item 3112. In the loaded position, the bladder element 3115 rebounds and deforms because the force F is applied substantially above the central segment 3116 of the tubular cavities 3181A, 3181B, and 3181C, such that the top of the central segment 3116 is closer to the flange 3122 in the loaded position than in the unloaded position.

[0264] When the tubular cavities 3181A, 3181B, and 3181C are compressed, some of the fluid in the fluid-filled internal cavities 3181A, 3181B, and 3181C can be transferred to the reservoirs 3183A, 3183B, resulting in the expansion and outward bulging of the reservoirs, as Figure 78 represented at the reservoir 3183A in. When the applied force F is removed, as the transferred fluid returns from the reservoirs 3183A, 3183B to the tubular cavities 3181A, 3181B, and 3181C, the rebounded and deformed bladder element 3115 returns to the Figure 77 unloaded position, causing the tubular cavities 3181A, 3181B, 3181C to expand to their original shape and the dimensions of the reservoirs 3183A, 3183B to decrease to their original shape.

[0265] Figure 79 Shows another embodiment of the heel spring device 3210 for the Figures 80 to 82 footwear item 3212 shown in. The heel spring device 3210 has similar functions and features to the heel spring device 10. For example, the device 3210 has a control bar 14 with an inner arm 18 and an outer arm 20. The device 3210 has a continuous base 22 connecting the side arms 18, 20 and extending rearward from the junction of the control bar 14 and the base 22. The base 22 is located below the control bar 14, where the first side arm 18 is located on the inner side 41 of the footwear upper 38, the second side arm 20 is located on the outer side 43 of the footwear upper 38, and the central segment 16 of the control bar 14 is located behind the ankle opening 39 of the upper 38.

[0266] The base 22 supports the control bar 14 and is connected to the control bar 14 at the elastically bendable joints 3224A, 3224B. The base 22 is continuous and extends between and is connected to the first side arm 18 and the second side arm 20. The base 22 is continuous because it does not break or pass through a connection portion of other components when extending from the first side arm 18 to the second side arm 20. The base 22 has a central segment 26, a first base arm 28, and a second base arm 30, all of which are disposed in a common plane, as described for the device 10 in reference Figure 3 The first base arm 28 is spaced apart from the second base arm 30, and both extend from the central segment 26 of the base 22.

[0267] The joints 3224A, 3224B include a first joint 3224A and a second joint 3224B. The base 22 and the first side arm 18 are connected at the first joint 3224A, and the base 22 and the second side arm 20 are connected at the second joint 3224B. The first joint 3224A is a connecting member between the first base arm 28 and the first side arm 18. The second joint 3224B is a connecting member between the second base arm 30 and the second side arm 20. The joints 3224A, 3224B may be referred to herein as hinge joints or hinge joints.

[0268] The control bar 14 has an arcuate shape from the first joint 3224A to the second joint 3224B. Similarly, the base 22 has an arcuate shape from the first joint 3224A to the second joint 3224B. With this arrangement, the control bar 14 and the base 22 are configured as a full-elliptical leaf spring as described herein. The device 3210 may be referred to as a heel spring. Additionally, the device 3210 is a single, integral, one-piece component. For example, the device 3210 may be injection molded as a single, integral, one-piece component.

[0269] The central segment 16 of the control bar 14 has a ramp surface 50 that slopes towards the inner periphery of the central segment 16 between the first side arm 18 and the second side arm 20, and as described for the device 10, helps to guide the foot downward and forward into the foot receiving cavity 47 during the application of a downward force F on the control bar 16. In addition, the first side arm 18 and the second side arm 20 each twist outward along their respective longitudinal axes from the joints 3224A, 3224B near the base 22 to the central segment 16 of the control bar 14. The outward twist helps to promote the downward and backward movement of the central segment 16 during foot loading.

[0270] The footwear article 3212 includes a sole structure 3232, and the flexible footwear upper 38 has an inner side 41 and an outer side 43, and defines an ankle opening 39 and a foot receiving cavity 47, as described with respect to the footwear article 12. The sole structure 3232 includes one or more sole components, and the one or more sole components may be a sole layer, such as an outsole, a midsole, or a sole layer 3234, and the sole layer 3234 is an integral combination of the outsole and the midsole and may be referred to as a unisole. The sole layer 3234 is located below the upper 38 and the foot receiving cavity 47 defined by the upper 38. The lower portion 40 of the footwear upper 38 is fixed to the sole layer 3234, such as by an adhesive or other means. The base 22 is fixed to the sole layer 3234, such as by bonding using an adhesive, heat bonding, or other means.

[0271] As Figure 83 best shown in, the sole layer 3234 has minute recesses 3219 in the outer wall 3217 of the sole layer 3234 (i.e., in the outer wall and the rear wall in the heel region of the sole layer 3234). The recesses 3219 are shaped to allow the base 22 and the joints 3224A, 3224B to be partially seated in the recesses 3219. The portions of the base 22 and the joints 3224A, 3224B seated in the recesses 3219 are fixed to the outer wall 3217 of the sole layer 3234 in the recesses 3219. Accordingly, the device 3210 is supported by the sole layer 3234 in the recesses 3219.

[0272] The control bar 14 is biased to Figure 80 and Figure 82 the unloaded position shown in. The unloaded position is also referred to herein as the stress-free position. The control bar 14 is internally biased to the stress-free position due to its material in its formed state. In other words, the material of the control bar 14 has sufficient rigidity such that in the absence of an external load being applied to it, it remains in the stress-free position in its natural state and, due to its elasticity, will return to the stress-free position after elastic bending. In the stress-free position, the central segment 16 is a first distance D1 from the bottom of the central segment 26 of the base 22, as represented by the distance D1 from the top of the central segment 16 of the control bar 14 to the bottom of the central segment 26 of the base 22 in Figure 80 The stress-free position is the position where the device 3210 is in a relaxed, unloaded state (i.e., no vertical force is applied to the control bar 14). The control bar 14 can be depressed under the action of the force F shown in Figure 80 which the force F represents when the foot is inserted into the foot receiving cavity 47 of the footwear article 3212 (e.g., see Figure 5 and Figure 6) The force applied by the foot during that period. When loaded in this manner, the control bar 14 elastically bends to the loaded position, in which the top of the central segment 16 is a second distance D2 from the bottom of the central segment 26 of the base 22. The loaded position is shown in Figure 80 where the control bar 14 and the central segment 16 are shown in dashed lines, and the central segment is shown in Figure 80 with reference numeral 16A. The second distance D2 is greater than the first distance D1. The difference between the distances D1 and D2 is the deflection of the device 3210, which can be, but is not limited to, a deflection of 30 mm. The device 3210 is configured such that when it is depressed to the loaded position D2 under the action of the force F, it elastically bends at the joints 3224A, 3224B, thereby storing elastic energy. When the force F is removed, the stored elastic energy causes the control bar 14 to return to the stress-free position. Similar to the device 10, when the control bar 14 is in the unloaded position, the first side arm 18 and the second side arm 20 extend at a first acute angle A1 with respect to the common plane P of the base 22. When the control bar 14 is depressed, the first side arm 18 and the second side arm 20 extend at a second acute angle A2 with respect to the common plane P of the base 22. The second acute angle A2 is less than the first acute angle A1.

[0273] As Figure 82 best shown, the base 22 extends from the outer side 43 to the inner side 41 around the rearmost portion of the footwear upper 38. As Figure 82 shown, the device 3210 is not fixed to the upper 38 at the inner side 41 or the outer side 43. Instead, the device 3210 is fixed to the upper 38 only via the heel tab 3249, which extends through the hole 3245 in the central segment 16. Next, the tab 3249 is stitched to the rear portion 3247 of the upper 38 at the stitch 3241. The decorative buckle 3243 can be fixed to the tab 3249. However, in the illustrated embodiment, the decorative buckle 3243 is merely decorative as it does not buckle or otherwise fasten to the upper 38.

[0274] Figure 84 Best shown, the inner arm 18 and the outer arm 20 are asymmetric with respect to the longitudinal axis L passing through the base 22 and extending between the inner arm 18 and the outer arm 20. The inner arm 18 is also referred to herein as the first side arm, and the outer arm 20 is also referred to as the second side arm. The inner arm 18 can be shorter than the outer arm 20 and can have a greater outer (i.e., outward) curvature than the outer arm, similar to the shape of the typical heel region of the foot. Because the heel device 3210 is shaped asymmetrically in this way according to the typical shape of the foot, the pressure of the heel device 3210 against the side of the foot during wear is thus minimized.

[0275] Figures 85 to 86FIG. illustrates another embodiment of the heel spring device 3310, which has many of the same features as the heel spring devices 10, 3210, and these features are denoted by similar reference numerals. Additionally, the base 22 has an inwardly extending flange 3221 that continuously extends from the inner base side arm 28 around the central segment 26 to the outer base side arm 30, such that the flange 3221 is generally U-shaped.

[0276] Reference Figure 87 , the heel spring device 3310 is included in a footwear item 3312 having an upper 38 and a sole structure 3332. The upper 38 is as described herein with respect to the heel spring device 10 and is shown only in dashed lines in Figure 87 . The sole structure 3332 includes an outer sole layer 3334, which can serve as an integral outsole and midsole. The sole structure 3332 also includes an inner sole layer 3345 that covers the sole layer 3334 and is also referred to as an insole. Figure 89 The sole layer 3334 is shown separately with the inner sole layer 3345 removed. The sole layer 3334 has a recess 3349 in the upper surface 3347. The recess 3349 is shaped such that the flange 3221 is located in the recess 3349 and at least partially seated in the recess 3349 and is fixed to the upper surface 3347 in the heel region of the sole structure 3332. Figure 90 The flange 3221 located in the recess 3349 is shown. The heel spring device 3310 is fixed to the sole layer 3334 by thermally bonding, an adhesive, or other means to fix the flange 3221 to the upper surface 3347 of the sole layer 3334 in the recess 3349. Then the inner sole layer 3345 is inserted into the upper 38 to rest on the sole layer 3334 above the flange 3221 and at the upper surface 3347 of the sole layer 3334.

[0277] As Figure 90 best shown in, the heel spring device 3310 is asymmetric about the longitudinal axis L. More specifically, the inner arm 18 bends laterally outward more than the outer arm 20 and is also longer than the outer arm 20 in the anterior-posterior direction (along the longitudinal axis L). As discussed with respect to the heel spring device 3210, this is a more anatomical shape than a symmetric heel spring device and avoids undesired friction and pressure on the foot from the side arms 18, 20.

[0278] The heel spring device 3310 is configured to be fixed to the upper 38 at the foremost portions of the side arms 18, 20 and via a heel tab that extends through a hole 3245 in the central segment 16, as Figure 87as indicated by the shoe upper 38 shown in dashed lines. More specifically, the foremost portion 3371 of the inner surface 3373 of the first side arm 18 includes an inner recess 3374 such that the first side arm 18 is thinner at the inner recess 3374 than behind the inner recess 3374. The foremost portion 3375 of the inner surface 3377 of the second side arm 20 includes an outer recess 3376 such that the second side arm 20 is thinner at the outer recess 3376 than behind the outer recess 3376. The shoe upper 38 can be fixed to the first side arm 18 at the inner recess 3374 and to the second side arm 20 at the outer recess 3376. For example, the shoe upper 38 can be joined to the side arms 18, 20 at the recesses 3374, 3376. In some embodiments, as Figure 88 shown, the shoe upper can include an inner portion 38B and an outer portion 38A. In such an embodiment, the outer portion 38A can include a flange 38C that extends rearward and is thinner than a more forward portion of the outer portion 38A. The flange 38C mates with and is fixed to the inner surfaces 3373, 3377 of the side arms 18, 20 at the recesses 3374, 3376. The outer portion 38A can be less flexible than the inner portion 38B and can thus provide better anchoring support for the device 3310 at the arms 18, 20 than the inner portion 38B.

[0279] In addition to being attached to the shoe upper 38 (or the outer portion 38A) at the foremost portions 3371, 3375, the shoe upper 38 can also be fixed to the heel spring device 3310 via a heel tab 3249 (see Figure 87 and Figure 91 ). The heel tab 3249 extends through a hole 3245 in the central segment 16. After the tab 3249 extends through the hole 3245, the tab 3249 can be folded into a loop and stitched to itself at a stitch 3285 as shown in Figure 92 . Then, a pin 3283 can be inserted into an opening 3281 in the loop of the tab 3249. The pin 3283 can be fixed to the tab 3249 in the opening 3281 behind the hole 3245, such as by inserting an adhesive into the opening 3281. The tab 3249 with the pin 3283 therein can be wider than the hole 3245. For example, the pin 3283 has a width 3286 that is greater than the width 3287 of the hole 3245 (see Figure 91 ). As the pin 3283 is inserted into the looped tab 3249, after pulling the tab 3249 through the hole 3245, the pin 3283 helps to hold the tab 3249 in the position of extending through the hole 3245 and thus helps to fix the shoe upper 38 to the device 3310 via the tab 3249. The tab 3249 is thus anchored to the central segment 16 by the pin 3283.

[0280] Figures 93 to 94Shown is a heel spring device 3410, which has many of the same features as heel spring devices 10 and 3210. Like reference numerals are used to refer to these features. Device 3410 includes a lever 3489 that extends laterally outward from control bar 14. Lever 3489 may also be referred to as a ledge extension or a shelf. Lever 3489 is disposed partially along inner arm 18 and partially along central segment 16. Within the scope of the present disclosure, lever 3489 may be disposed anywhere along control bar 14. Lever 3489 has an upward-facing surface 3491, and this upward-facing surface 3491 can be pressed downward in a manner similar to that described for the force F acting on central segment 16 with respect to Figure 80 . Pressing down on lever 3489 helps to press control bar 14 from an unstressed position to a stressed position. Surface 3491 has a recessed groove 3493 such that surface 3491 is not smooth, thereby enhancing the ability to grip surface 3491 when pressing down on lever 3489. Figure 94 A rear view of a footwear item 3412 is shown, the footwear item 3412 including device 3410 that is secured to shoe sole layer 3434 and upper 38.

[0281] Various embodiments of the heel spring device disclosed herein enhance the convenience of foot entry, thereby allowing the foot to enter the footwear item without the use of the hands.

[0282] The following articles provide example configurations of the footwear item, device, and footwear upper disclosed herein.

[0283] Article 1: A device configured to surround a portion of a foot receiving cavity in a heel region of a footwear item, the device including a control bar having a central segment, a first side arm extending from the central segment, and a second side arm spaced from the first side arm and extending from the central segment; a continuous base that supports the control bar and is connected to both the first side arm and the second side arm; and wherein the control bar is biased to an unstressed position at which the central segment is a first distance from the base, the control bar elastically deforming to a loaded position under an applied force at which the central segment is a second distance from the base that is less than the first distance, and the device stores potential energy that causes the control bar to return to the unstressed position when the applied load is removed.

[0284] Article 2: The device according to Article 1, wherein the base is connected to the first side arm at a first joint and the base is connected to the second side arm at a second joint.

[0285] Clause 3: The device according to Clause 2, wherein: the control bar has an arcuate shape from the first joint to the second joint; the base has an arcuate shape from the first joint to the second joint; and the control bar and the base are configured as a full elliptical leaf spring.

[0286] Clause 4: The device according to any one of Clauses 2 to 3, wherein: the base has a central segment, a first base arm, and a second base arm all disposed in a common plane; the first base arm is spaced from the second base arm, and both extend from the central segment of the base; the first base arm and the first side arm are connected at the first joint; the second base arm and the second side arm are connected at the second joint; when the control bar is in the stress-free position, the first side arm and the second side arm extend at an acute angle relative to the common plane of the base; when the control bar is in the loaded position, the first side arm and the second side arm extend at a second acute angle relative to the common plane of the base; and the second acute angle is less than the first acute angle.

[0287] Clause 5: The device according to any one of Clauses 1 to 4, wherein the central segment of the control bar has a ramp surface that slopes toward the inner perimeter of the central segment between the first side arm and the second side arm.

[0288] Clause 6: The device according to any one of Clauses 1 to 5, wherein both the first side arm and the second side arm are twisted outward from the base to the central segment of the control bar along their respective longitudinal axes.

[0289] Clause 7: The device according to any one of Clauses 1 to 6, wherein the first side arm and the second side arm are asymmetric with respect to a longitudinal axis extending through the base between the first side arm and the second side arm.

[0290] Clause 8: The device according to any one of Clauses 1 to 7, wherein the base has a flange extending inward.

[0291] Clause 9: The device according to Clause 8, in combination with a sole structure having a foot receiving surface that has a recess in the heel region; and wherein the flange is seated in the recess and fixed to the foot receiving surface.

[0292] Clause 10: The device according to any one of Clauses 1 to 7, in combination with a sole structure having an outer wall that has a recess in the heel region; and wherein at least a portion of the base of the device is seated in the recess and fixed to the outer wall of the sole structure.

[0293] Clause 11: The device according to any one of Clauses 1 to 10, which is combined with a footwear upper that defines at least a part of an ankle opening, wherein the base is located below the control bar, the first side arm is located at the inner side surface of the upper, the second side arm is located at the outer side surface of the upper, and the central segment of the control bar is located behind the ankle opening.

[0294] Clause 12: The device according to Clause 11, wherein the foremost part of the inner surface of the first side arm includes an inner concave portion such that the first side arm is thinner at the inner concave portion than behind the inner concave portion, and the foremost part of the inner surface of the second side arm includes an outer concave portion such that the second side arm is thinner at the outer concave portion than behind the outer concave portion; and wherein the upper is fixed to the second side arm at the outer concave portion and to the first side arm at the inner concave portion.

[0295] Clause 13: The device according to any one of Clauses 1 to 12, wherein the central segment has a hole; and wherein the upper includes a tab that extends through the hole.

[0296] Clause 14: The device according to Clause 13, wherein the tab is fixed to the rear part of the footwear upper.

[0297] Clause 15: The device according to Clause 13, further comprising: a pin that is fixed to the tab behind the hole, wherein the tab with the pin thereon is wider than the hole such that the tab is anchored to the central segment by the pin.

[0298] Clause 16: The device according to any one of Clauses 1 to 15, further comprising: a lever that extends outward from the control bar.

[0299] Clause 17: The device according to any one of Clauses 1 to 16, wherein each of the first side arm and the second side arm has at least one slot extending therethrough.

[0300] Clause 18: The device according to Clause 17, wherein the control bar includes a series of slats, each slat extending along the first side arm, the central segment, and the second side arm, and wherein the at least one slot includes a series of slots, each slot extending along the first side arm, the central segment, and the second side arm and being disposed between corresponding adjacent slats in the slats.

[0301] Clause 19: The device according to any one of Clauses 1 to 16, wherein the device includes a bladder element that includes one or more fluid-filled internal cavities.

[0302] Clause 20: The device according to Clause 19, wherein: the one or more fluid-filled internal cavities include: a cavity extending along the central segment; and one or more reservoirs, the one or more reservoirs being provided at one or both of the first side arm and the second side arm and being in fluid communication with the cavity extending along the central segment; and when the heel spring means is elastically deformed under the applied force, the one or more reservoirs expand as fluid is transferred from the cavity extending along the central segment.

[0303] Clause 21: The device according to any one of Clauses 1 to 18, wherein when the control bar is in the loading position, the first side arm and the second side arm bend apart from each other.

[0304] Clause 22: The device according to any one of Clauses 1 to 18, wherein: one of the control bar and the base has an extension extending towards the other of the control bar and the base; and when the control bar is in the stress-free position, the extension is spaced apart from the other of the control bar and the base, and when the control bar is in the loading position, the extension contacts the other of the control bar and the base, thereby restricting further downward pressing of the control bar.

[0305] Clause 23: The device according to Clause 22, wherein: the extension extends from the central segment of the control bar towards the base; the base has a recess; and when the control bar is in the stress-free position, the extension is spaced apart from the base, and when the control bar is in the loading position, the extension projects into the recess.

[0306] Clause 24: The device according to Clause 11, wherein the control bar is embedded in the footwear upper.

[0307] Clause 25: The device according to Clause 11, wherein the base has a forward extension below the foot receiving space adjacent to the inner side of the upper and a rearward extension below the foot receiving space along the outer side of the upper.

[0308] Clause 26: The device according to Clause 1, wherein the base is coupled to the foremost portions of the first side arm and the second side arm.

[0309] Clause 27: The device according to Clause 1, wherein the base extends rearward from the control bar.

[0310] Clause 28: The device according to Clause 1, wherein the base extends forward from the control bar.

[0311] Clause 29: The device according to Clause 1, wherein the base is the sole structure of a footwear item.

[0312] Clause 30: The device according to Clause 1, wherein the base is a flexible footwear upper.

[0313] Clause 31: The device according to any one of Clauses 1 to 30, wherein the device is a single, integral, one-piece component.

[0314] Clause 32: A device for facilitating entry of a foot into a footwear item and configured to surround a portion of a foot receiving cavity in a heel region of the footwear item, the device comprising: a control bar and a base located below the control bar; wherein the control bar includes a series of slats, each slat having: a central segment; an inner arm extending from the central segment to an inner end connected to an inner side of the base; and an outer arm extending from the central segment to an outer end connected to an outer side of the base; and wherein the control bar is biased to an unloaded position and elastically bends to a loaded position under the action of an applied force, at least one central segment being closer to the base in the loaded position than in the unloaded position, thereby storing potential energy that causes the control bar to return to the unloaded position when the applied load is removed.

[0315] Clause 33: The device according to Clause 32, wherein the control bar and the base are configured as a full elliptical leaf spring.

[0316] Clause 34: The device according to any one of Clauses 32 and 33, wherein: the control bar defines a slot extending between the slats; the slats are spaced apart from each other by the slot when the control bar is in the unloaded position; and one or more of the slots close between the slats such that one or more adjacent central segments contact each other in the loaded position.

[0317] Clause 35: The device according to Clause 34, wherein: the slots are parallel to each other; and outer sides of the slats are flush with each other in the unloaded position.

[0318] Clause 36: The device according to any one of Clauses 32 to 35, wherein the lowermost slat closest to the base at the central segment is shorter from the inner end to the outer end than the uppermost slat furthest from the central segment among the slats; and wherein the lowermost slat is thinner than the uppermost slat.

[0319] Clause 37: The device according to any one of Clauses 32 to 36, wherein the lowermost one of the slats has a tab extending from the lower edge of the central segment.

[0320] Clause 38: The device according to any one of Clauses 32 to 37, wherein the outer surface of the base has a peripheral recess extending from the lower edge of the base.

[0321] Clause 39: The device according to any one of Clauses 32 to 38, further comprising: an elastic insert at least partially filling the slot.

[0322] Clause 40: The device according to Clause 39, wherein the elastic insert includes: a bushing extending along the inner side of the slat; and spaced protrusions extending from the bushing into the slot.

[0323] Clause 41: The device according to Clause 39, wherein the elastic insert is configured as a pleated member that extends outwardly between the slats from the inner side of the slat.

[0324] Clause 42: The device according to any one of Clauses 39 to 41, wherein the elastic insert includes at least one of rubber or thermoplastic polyurethane.

[0325] Clause 43: A device for facilitating entry of a foot into a footwear item and configured to surround a portion of a foot receiving cavity in a heel region of the footwear item, the device comprising: an elastic corrugated body including a central segment, an inner arm extending forward from the central segment, and an outer arm extending forward from the central segment; wherein the corrugated body includes alternating ridges and grooves that extend in a lengthwise direction along the inner arm, the central segment, and the outer arm; and wherein the corrugated body is biased to an unloaded position and compressed to a loaded position under the action of an applied force, with one or more adjacent ridges in the alternating ridges being closer to each other in the loaded position than in the unloaded position, thereby storing elastic energy that causes the corrugated body to return to the unloaded position when the applied load is removed.

[0326] Clause 44: The device according to Clause 43, wherein: the corrugated body includes a pleated member; and the ridges are the convex pleats of the pleated member, while the grooves are the concave folds of the pleated member.

[0327] Clause 45: The device according to Clause 44, wherein: a first set of ridges and grooves extends from the inner arm to the outer arm, and a second set of ridges and grooves extends only along the central segment.

[0328] Clause 46: The device according to any one of Clauses 43 to 45 further includes an upper flange extending along the upper edge of the corrugated body at the central segment.

[0329] Clause 47: The device according to any one of Clauses 43 to 46 further includes a lower flange extending along the lower edge of the corrugated body at the inner arm, the central segment, and the outer arm.

[0330] Clause 48: The device according to any one of Clauses 43 to 47, wherein the corrugated body is at least one of rubber or thermoplastic polyurethane.

[0331] Clause 49: A footwear item, comprising: an upper defining at least a portion of an ankle opening; a sole structure fixed to the upper and located below the upper; and a heel spring device including: a central segment fixed to the upper behind the ankle opening; an inner arm extending downward and forward from the central segment; an outer arm extending downward and forward from the central segment; and a base connected to both the inner arm and the outer arm; wherein the base is fixed to the sole structure; and wherein the central segment is biased to an unloaded position, the heel spring device elastically deforms to a loaded position under an applied force, the central segment is closer to the base in the loaded position than in the unloaded position, and the heel spring device stores elastic energy that returns the central segment to the unloaded position when the applied load is removed, and the upper moves with the central segment such that the ankle opening is closer to the sole structure when the central segment is in the loaded position than when the central segment is in the unloaded position.

[0332] Clause 50: The footwear item according to Clause 49, wherein: the sole structure includes a midsole; and the base is partially recessed into the midsole.

[0333] Clause 51: The footwear item according to any one of Clauses 49 to 50, wherein the inner arm is fixed to the inner side of the upper, and the outer arm is fixed to the outer side of the upper.

[0334] Clause 52. The footwear item according to Clause 51, wherein when the central segment is in the loaded position, the inner arm and the outer arm bend laterally outwardly and away from each other to widen the ankle opening.

[0335] Clause 53: A footwear article according to any one of Clauses 49 to 52, wherein, in the unloaded position, the central segment is spaced apart from the base, and the device is characterized in that: at the rear of the joint between the inner arm and the base and at the rear of the joint between the outer arm and the base, there is no rigid heel stabilizer located between the central segment and the base.

[0336] Clause 54: A footwear article according to any one of Clauses 49 to 53, wherein each of the inner arm and the outer arm is torsionally outward from the base to the central segment along their respective longitudinal axes.

[0337] Clause 55: A footwear article according to any one of Clauses 49 to 54, wherein: one of the central segment and the base has an extension that at least partially extends towards the other of the central segment and the base; and when the central segment is in the unloaded position, the extension is spaced apart from the other of the central segment and the base.

[0338] Clause 56: A footwear article according to Clause 55, wherein: the extension extends at least partially from the central segment towards the base; the base has a recess; and when the central segment is in the unloaded position, the extension is spaced apart from the base, and when the central segment is in the loaded position, the extension projects into the recess.

[0339] Clause 57: A footwear article according to Clause 55, wherein the extension extends at least partially from the central segment towards the base; and further includes: a strip having a proximal end fixed to the upper and a chamber at the distal end; and the extension is disposed in the chamber, wherein the strip covers the central segment.

[0340] Clause 58: A footwear article according to any one of Clauses 49 to 57, wherein: the outer surface of the base has a peripheral recess extending from the lower edge of the base; and the sole structure has a flange disposed in the peripheral recess.

[0341] Clause 59: A footwear article according to any one of Clauses 49 to 58, wherein the central segment has a ramp surface that slopes towards the inner perimeter of the central segment between the inner arm and the outer arm.

[0342] Clause 60: A footwear article according to any one of Clauses 49 to 59, wherein the heel spring device is a single, integral, one-piece component.

[0343] Clause 61: The footwear article according to Clause 49, wherein the heel spring device includes a bladder element, and the bladder element includes one or more fluid-filled internal cavities.

[0344] Clause 62: The footwear article according to Clause 61, wherein: the one or more fluid-filled internal cavities include: a cavity extending along the central segment; and one or more reservoirs disposed at one or both of the medial arm and the lateral arm and in fluid communication with the cavity extending along the central segment; and when the heel spring device elastically deforms under the applied force, the one or more reservoirs expand as fluid is transferred from the cavity extending along the central segment.

[0345] Clause 63: A footwear upper, comprising: a flexible covering that defines at least a portion of an ankle opening; a heel spring device including: a control bar having: a central segment fixed to the flexible covering behind the ankle opening; a medial arm extending from the central segment and fixed to the inner side of the flexible covering; and a lateral arm extending from the central segment and fixed to the outer side of the flexible covering; and a continuous base that supports the control bar and is connected to both the medial arm and the lateral arm; and wherein the control bar is biased to a stress-free position where the central segment is a first distance from the base, and the control bar elastically deforms to a loaded position under the applied force where the central segment is a second distance from the base that is less than the first distance, and the heel spring device stores potential energy that returns the control bar to the stress-free position when the applied load is removed.

[0346] Clause 64: The footwear upper according to Clause 63, wherein the flexible covering is an elastically stretchable fabric and further includes a collar fixed to the flexible covering and defining a front portion of the ankle opening; wherein the collar is stiffer than the elastically stretchable fabric.

[0347] Clause 65: The footwear upper according to any one of Clauses 63 to 64, further comprising: a heel tab fixed to the flexible covering; wherein the central segment of the control bar has a hole, and the heel tab extends through the hole.

[0348] Clause 66: The footwear upper according to any one of Clauses 63 to 65, wherein when the central segment is in the loaded position, the medial arm and the lateral arm bend laterally outwardly and away from each other, thereby widening the ankle opening of the flexible covering.

[0349] Clause 67: The footwear upper according to any one of Clauses 63 to 66, characterized in that at the rear of the joint between the control strip and the base, there is no rigid heel stabilizer located between the control strip and the base.

[0350] Clause 68: The footwear upper according to any one of Clauses 63 to 67, wherein each of the inner arm and the outer arm is twisted outward from the base to the central segment of the control strip along their respective longitudinal axes.

[0351] Clause 69: The footwear upper according to any one of Clauses 63 to 68, wherein: one of the control strip and the base has an extension extending towards the other of the control strip and the base; and when the control strip is in the stress-free position, the extension is spaced apart from the other of the control strip and the base, and when the control strip is in the loaded position, the extension contacts the other of the control strip and the base, thereby restricting further downward pressing of the control strip.

[0352] Clause 70: The footwear upper according to Clause 69, wherein: the central segment of the control strip has an extension extending towards the base; the base has a recess; and when the control strip is in the stress-free position, the extension is spaced apart from the base, and when the control strip is in the loaded position, the extension projects into the recess.

[0353] Clause 71: The footwear upper according to any one of Clauses 63 to 70, wherein the central segment of the control strip has a ramp surface that slopes towards the inner perimeter of the central segment between the inner arm and the outer arm.

[0354] Clause 72: The footwear upper according to any one of Clauses 63 to 71, wherein the heel spring device is a single, integral, one-piece component.

[0355] Clause 73: The footwear upper according to Clause 63, wherein the heel spring device includes a bladder element that includes one or more fluid-filled internal cavities.

[0356] Clause 74: The footwear upper according to Clause 73, wherein: the one or more fluid-filled internal cavities include: a cavity extending along the central segment; and one or more reservoirs disposed at one or both of the medial arm and the lateral arm and in fluid communication with the cavity extending along the central segment; and when the heel spring means is elastically deformed under the applied force, the one or more reservoirs expand as fluid is transferred from the cavity extending along the central segment.

[0357] Clause 75: A footwear item comprising: a footwear upper including a flexible covering defining at least a portion of an ankle opening; a sole structure secured to and located beneath the footwear upper; heel spring means including: a control bar having: a central segment fixed to the flexible covering behind the ankle opening; a medial arm extending downwardly and forwardly from the central segment along the inner side of the footwear upper; and a lateral arm extending downwardly and forwardly from the central segment along the outer side of the footwear upper; and a spring operatively connected to the control bar and biasing the control bar to a stress-free position; and wherein the control bar pivots rearwardly to a loaded position under the applied force, thereby storing potential energy in the spring, the potential energy causing the control bar to return to the stress-free position when the applied load is removed, the flexible covering moving with the control bar.

[0358] Article 76: The footwear item according to Clause 75, further comprising: a pin connected to both the medial arm and the lateral arm and extending through the sole structure; and wherein the spring is wound around the pin and has an end fixed to pivot with the control bar and another end fixed relative to the control bar.

[0359] Article 77: An article of footwear comprising: a footwear upper including a flexible covering that defines at least a portion of an ankle opening; a sole structure secured to the footwear upper and positioned below the footwear upper; a heel spring device including: a rear control bar having: a central segment secured to the flexible covering behind the ankle opening; an inner arm extending downwardly and forwardly from the central segment along an inner side of the footwear upper; and an outer arm extending downwardly and forwardly from the central segment along an outer side of the footwear upper; a front bar having: a central segment secured to the flexible covering in front of the ankle opening; an inner wall extending downwardly and rearwardly from the central segment along an inner side of the upper; and an outer arm extending downwardly and rearwardly from the central segment along an outer side of the upper; wherein the front bar and the rear control bar cross and are secured to one another at the outer side of the footwear upper and at the inner side of the footwear upper; and wherein the rear control bar pivots rearwardly to a loaded position under an applied force to store potential energy, the potential energy causing the rear control bar to return to a stress-free position when the applied load is removed, the flexible covering moving with the rear control bar.

[0360] The terms "a", "an", "the", "at least one", and "one or more" are used interchangeably to indicate the presence of at least one item. Unless the context clearly dictates otherwise, there may be more than one such item. All numerical values of parameters (e.g., amounts or conditions) in this specification (including the appended claims) should be understood to be modified in all instances by the term "about", whether or not the term "about" actually appears before the numerical value, unless the context clearly and unambiguously dictates otherwise. "About" means that the stated numerical value allows for some slight imprecision (some proximity to the exact value; approximately or moderately close to the value; nearly). If the imprecision provided by "about" is not otherwise understood in the art in this ordinary sense, then "about" as used herein means at least the variation that may be caused by the ordinary methods of measuring and using such parameters. Additionally, the disclosed ranges should be understood to specifically disclose all values and further divided ranges within that range. All references cited herein are hereby incorporated by reference in their entirety.

[0361] The terms "comprising", "including", and "having" are inclusive and thus specify the presence of the stated features, steps, operations, elements, or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, or components. The order of steps, processes, and operations may be changed where possible, and additional or alternative steps may be employed. As used in this specification, the term "or" includes any and all combinations of the associated listed items. The term "any" is understood to include any possible combination of the recited items, including "any one" of the recited items. The term "either" is understood to include any possible combination of the recited claims in the appended claims, including "any one" of the recited claims.

[0362] Those of ordinary skill in the art will recognize terms such as "above", "below", "upward", "downward", "top", "bottom", etc. These may be used descriptively with respect to the drawings and do not represent a limitation on the scope of the invention as defined by the claims.

[0363] Although several modes for implementing many aspects of the present teachings have been described in detail, those skilled in the art familiar with the fields involved in these teachings will recognize various alternative aspects of implementing the present teachings within the scope of the appended claims. Note that all of the content included in the above description or shown in the drawings should be construed as merely illustrative and not limiting.

Claims

1. An article of footwear, comprising: a footwear upper that defines at least a portion of an ankle opening and a foot receiving cavity; a sole structure that is secured to the footwear upper and is located below the footwear upper; a heel spring assembly for facilitating entry of a foot into the foot receiving cavity, configured to surround a portion of the foot receiving cavity in a heel region of the article of footwear, comprising: a control bar that is operably connected to the footwear upper and has: a central segment disposed rearward of the ankle opening; an inner side arm that extends downwardly and forwardly from the central segment on an inner side of the footwear upper; and an outer side arm that extends downwardly and forwardly from the central segment on an outer side of the footwear upper; and a base that is located below the control bar and below the foot receiving cavity; wherein the heel spring assembly is secured to a shoe bed layer of the sole structure at the base and is secured to a flexible covering of the footwear upper; wherein the base extends rearwardly from an inner engagement portion of the inner side arm with the base and an outer engagement portion of the outer side arm with the base to serve as a support, the inner engagement portion and the outer engagement portion being elastically bendable; wherein when the control bar is depressed, the heel spring assembly laterally widens outwardly.

2. The footwear article according to claim 1, wherein, The inner engagement portion is at a foremost portion of the inner side arm; the outer engagement portion is at a foremost portion of the outer side arm.

3. The footwear article according to claim 1, wherein, The base includes and extends laterally from a foremost portion of the inner side arm to a foremost portion of the outer side arm below the foot receiving cavity.

4. The footwear article according to claim 1, wherein, The base extends rearwardly from the inner engagement portion and the outer engagement portion, and the inner side arm and the outer side arm extend from the base to the central segment at a gradually decreasing slope.

5. The footwear article according to claim 1, wherein, The base extends rearwardly from the inner engagement portion and the outer engagement portion, and the inner side arm and the outer side arm extend from the base to the central segment at a gradually increasing slope.

6. The footwear article according to claim 1, wherein, The inner side arm and the outer side arm each have a Z-shaped configuration and extend first rearwardly, then forwardly, and then again rearwardly from the inner engagement portion and the outer engagement portion, respectively, to the central segment of the control bar; wherein a junction of the rearward extending portion and the forward extending portion of the inner side arm and the outer side arm serves as an additional engagement portion for elastic bending caused by a downward force acting on the central segment of the control bar during loading of the heel spring assembly.

7. The article of footwear according to claim 1, wherein: the sole structure has a foot-facing surface with a recess; the base has a main portion and a protrusion extending downwardly from the main portion; the protrusion is located in the recess; 8. The footwear article according to claim 7, wherein, the protrusion forms a cavity in the recess; 9. The footwear article according to claim 7, wherein, a wall of the protrusion abuts a wall of the sole structure at the recess; 10. The footwear item according to claim 1, further comprising: a welt; wherein the base is below the welt.

11. The article of footwear according to claim 1, wherein: the base extends through an opening in the shoe bed layer and is secured to or embedded in the shoe bed layer.

12. The footwear article according to claim 1, wherein, The material of the control bar is rigid such that the control bar remains in a stress - free position without an external load being applied to it, and due to the elasticity of the material of the control bar, it will return to the stress - free position after elastic bending.

13. The footwear article according to any one of claims 1-12, wherein, The heel spring device is a single, integral, one - piece component.

14. A heel spring device for facilitating entry of a foot into a foot - receiving cavity at a heel region of a footwear item, the heel spring device comprising: A control bar and a continuous base, the control bar having: A central segment; An inner side arm configured to extend downwardly and forwardly from the central segment along an inner side of a footwear upper of the footwear item; An outer side arm configured to extend downwardly and forwardly from the central segment along an outer side of a footwear upper of the footwear item and spaced apart from the inner side arm; Among them, The base is connected to the control bar at an inner joint at a foremost portion of the inner side arm and at an outer joint at a foremost portion of the outer side arm, the base extending forwardly and rearwardly from the inner joint and the outer joint below the control bar, the inner joint and the outer joint being elastically bendable; Wherein the heel spring device is configured to be fixed to a sole structure of the footwear item at the base and is configured to secure a flexible covering of the footwear upper of the footwear item; Wherein each of the inner side arm and the outer side arm has at least one slot extending therethrough.

15. The heel spring device according to claim 14, wherein, The slot extends through the inner side arm and extends in a lengthwise direction along a longitudinal axis of the inner side arm; separate slots extend through the outer side arm and extend in a lengthwise direction along a longitudinal axis of the outer side arm, Wherein the slot reduces the thickness of the inner side arm and the outer side arm.

16. The heel spring device according to claim 15, wherein, By means of the slot, each of the inner side arm and the outer side arm is divided into a plurality of slats at the slot.

17. The heel spring device according to claim 16, wherein, In a loaded position, the inner side arm and the outer side arm are configured such that at least a portion of the slot closes, causing the slats to contact each other, thereby increasing stiffness and resistance to further bending, and the heel spring device stores elastic energy that causes the control bar to return to the stress - free position when the applied load is removed.

18. The heel spring device according to claim 14, wherein, The slot extends through the inner side arm and is transverse to the longitudinal axis of the inner side arm; Separate slots extend through the outer side arm and are transverse to the longitudinal axis of the outer side arm; Wherein the slot reduces the thickness of the inner side arm and the outer side arm.

19. The heel spring device according to claim 18, wherein, By means of the slot, each of the inner side arm and the outer side arm is divided into a plurality of fingers.

20. The heel spring device according to claim 19, wherein, In a loaded position, the inner side arm and the outer side arm are configured such that at least a portion of the slot closes, causing the fingers to contact each other, thereby increasing stiffness and resistance to further bending, and the heel spring device stores elastic energy that causes the control bar to return to the stress - free position when the applied load is removed.

21. The heel spring device according to any one of claims 14-20, wherein The heel spring device is a single, integral, one - piece component.

22. A footwear item comprising: A flexible footwear upper that defines at least a portion of an ankle opening; A sole structure including a shoe sole layer fixed to and located beneath the footwear upper; Heel spring means embedded in a flexible covering of the footwear upper, the heel spring means comprising: A control bar having: A central segment rearward of the ankle opening; An inner side arm extending downwardly and forwardly from the central segment on an inner side surface of the footwear upper; and An outer side arm extending downwardly and forwardly from the central segment on an outer side surface of the footwear upper and spaced apart from the inner side arm; A base that supports the control bar and is connected to the control bar at an elastically bendable joint; Wherein the base is fixed to the flexible footwear upper such that the base is located beneath the control bar and the base extends from an outer side surface to an inner side surface around a rearmost portion of the footwear upper.

23. The footwear article according to claim 22, wherein, The control bar is biased to an unloaded position and elastically bends to a loaded position under the action of an applied force, the central segment being closer to the base in the loaded position than in the unloaded position, thereby storing potential energy that causes the control bar to return to the unloaded position when the applied force is removed.

24. The footwear item according to any one of claims 22-23, wherein, The heel spring means is a single, integral, one-piece component.

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