HK1056300B - Shoe sole cushion and shoe sole - Google Patents

Description

Shoe sole liner and shoe sole

This application is a continuation of application No.08/985999 filed on 5.12.1997.

Technical Field

The present invention relates to a cushion for placement in a shoe sole for cushioning and supporting the foot. More particularly, the present invention relates to a cushion having a U-shaped tubular portion disposed about a central portion of a foot-supporting region.

Background

Resilient athletic shoe soles are constructed with a variety of resilient cushioning members for storing and absorbing impact energy imparted to the foot of the wearer. Many well-known shoe soles include fluid bladders that contain pressurized air, or viscous liquids or gels to absorb impact and store energy.

For example, U.S. patent No.5406719 discloses a bladder with compressed air. The bladder includes a heel support with a variety of air chambers. Some of the air chambers are disposed around the heel support and others of the air chambers are located in the center of the heel support. The gas confined in the chamber provides cushioning to the foot as the gas pressure increases with the loading in the chamber. This patent shows a central chamber in communication with the transverse chambers so that the internal air pressure between the chambers is the same.

U.S. patent No.5353459 also shows a bladder for cushioning the heel. The bladder has a horseshoe-shaped chamber extending around the periphery of the bladder from the inside to the outside of the rear portion thereof. There is also a central chamber within the horseshoe shaped chamber. As disclosed in the' 719 patent, the stiffness of the chambers is controlled by varying the air pressure therein.

U.S. patent No.4183156 discloses an insole-shaped insert having interconnected chambers forming air springs. Two of the chambers are tubular, extending around both sides and the rear of the heel of the insole. An additional two tubular chambers are disposed between the chambers, extending around both sides of the heel.

Cushioning bladders that employ gas or other fluids to cushion the impact of a foot have a number of disadvantages. These bladders often leak over time, and gas devices are particularly prone to pressure loss as the bladder ages. Moreover, the bladder is susceptible to puncture by sharp objects. Once the bladders are punctured, their contents are free to spill and the bladders are no longer effectively cushioned. Moreover, fluid-filled bladders also tend to bulge and/or compress over time. Most functions differ significantly at different temperatures due to changes in the pressure or viscosity of the fluid contained. Furthermore, because the fluid in each bladder facilitates equalisation of the pressure in each chamber of the bladder, compression of one part of the chamber can only squeeze fluid to another part of the chamber, reducing control over local deformation of the bladder and thus cushioning.

Other known soles utilize resilient structures that rely on the structural walls, rather than the fluid contained therein, to cushion the impact of the wearer's foot. For example, U.S. patent 5255451 shows a sole with an insert formed of a plurality of waves. U.S. patent 4774774 shows a midsole formed of a honeycomb structure. U.S. patent No.4342158 also shows a shoe sole with a conical coil spring member provided at the heel.

Disclosure of Invention

The present invention provides a cushion for use in a shoe sole. The cushion includes first and second resiliently loaded hollow tubular walls shaped to support and cushion respective edges of a wearer's foot. The tubular wall forms first and second tubular portions, preferably extending along first and second portions of the boundaries of the sole region. At least one, and preferably all, of the tubular portions extend along a third portion of the area facing each other, for example together, the tubular portions forming a U-shape adjacent each edge of the area. The insert is preferably disposed between the midsole and the outsole of the sole.

The cushion also has a resilient load-bearing central wall disposed generally centrally across the width of the foot and configured to support and cushion the laterally central portion of the foot. The central wall defines a hollow central portion and is located between and preferably connected to the tubular portions and preferably forms a unitary structure with the tubular walls. These tubular portions are preferably vertically stiffer than the central portion to stabilize the support area of the foot toward the central portion.

One embodiment of the liner provides a joint wherein the central wall and the first tubular wall are joined together such that vertical deformation of one of the central wall and the first tubular wall is transmitted to the other. This connection may be provided at the heel strike area of the wearer's foot to withstand the concentrated loads that are first generated during running.

The preferred embodiment has a recess in the central wall at the location where it is not connected to the tubular walls, which connects the central portion to the first tubular portion. Because the portion is concave and preferably does not have any significant length of walls vertically spaced, vertical deformation between the central wall and the first tubular wall disposed adjacent the recess is substantially isolated from each other.

Since the support of the pad is preferably provided by the load-bearing central and tubular walls themselves, any air trapped within the pad is preferably not pressurized, but rather at atmospheric pressure. This reduces the problems associated with prior art bladders that are pressurized with fluids or gases.

In another embodiment, the first and second hollow tubular portions have resiliently loaded first and second hollow walls, respectively. The cushion preferably has a weakened section between the first and second tubular portions, the weakened section preferably being adjacent a bend in at least one of the tubular portions that bends around the periphery of the central portion. The thinned region is more flexible than the tubular portions and allows the cushion to bend along a line extending between the tubular portions.

The preferred location for the sole of this embodiment is in an area corresponding to the foot that includes at least one metatarsal end of the foot. Two inserts may be used in a sole, for example adjacent and opposite each other in the sole region to define together a larger sole metatarsal tip region which includes some or all of the metatarsal tips, preferably at least the largest metatarsal tip. In this configuration, the first and second tubular portions of each cushion are most preferably generally aligned with the first and second tubular portions of the other cushion.

In this embodiment the insert is provided in an increased flexibility portion of the sole. The channels preferably extend generally laterally along this increased flexibility portion, preferably near the thinned area of the pad, to increase its flexibility in the front and rear portions.

Brief Description of Drawings

FIG. 1 is a bottom side sectional view of a padded left shoe constructed in accordance with the present invention;

FIG. 2 is a top view of the liner;

FIG. 3 is a front cross-sectional view of the gasket taken along the plane III-III in FIG. 2;

FIG. 4 is a top view of the impact trajectory to the foot contours during running;

FIG. 5 is a side view of the pad;

FIG. 6 is a side view of another embodiment of the liner;

FIG. 7 is a top view of another embodiment of a sole constructed according to the present invention;

FIG. 8 is a bottom view of the above embodiment;

FIG. 9 is a cross-sectional view of the sole taken along line III-III of FIG. 8;

figures 10-12 are top, rear, and medial side views of the forefoot pad of the sole;

FIG. 13 is a cross-sectional view taken along line XII-XII in FIG. 7;

FIG. 14 is a top view of another embodiment of a forefoot pad constructed in accordance with the invention;

detailed description of the preferred embodiments

Fig. 1 shows a shoe sole with a heel 16 that employs the preferred embodiment of the insert 10 of the present invention. The sole includes a midsole 12 and an outsole 14. In this embodiment, the insert 10 is an integral part of the midsole 12, but its lower portion is exposed and may contact the ground, and thus also serves as an outsole.

Referring to fig. 2, the pad has an outer tubular portion 24 comprising an inner tubular portion 18 and an outer tubular portion 20 formed by a resilient load-bearing tubular wall 19. The tubular portions 18 and 20 extend along the medial and lateral sides of the foot shape of the sole. In the preferred embodiment, tubular portions 18 and 20 extend along the medial and lateral sides of the heel shape generally in the heel area of the sole, facing toward central portion 26. While tubular portions 18 and 20 also extend along the rear heel-shaped edge, they preferably together form a single, substantially continuous outer tubular portion 24. This resultant tubular portion 24 extends continuously in a U-shape substantially along the contour of the heel shape. The wall 19 forming the outer tubular portion 24 is preferably configured and dimensioned so that the wall 19, together with the main sole, supports the edges of the foot and cushions impacts thereto, for example caused by walking, running or jumping, without damage.

A hollow center portion 26 is disposed between and connected to the inboard and outboard portions 18 and 29. The central portion 26 is formed by a resiliently loaded central wall 28. Preferably, the central wall 28 is joined to the tubular wall 19 along a portion of its boundary 21, preferably along the entire boundary length of the central portion 26 adjacent the tubular portion 24, including the inner, outer and rear sides of the central portion 26, although in other embodiments the walls may be joined less than the entire boundary length or may be formed from separate pieces of material. The curved portions 23 of the tubular portions 18 and 20 are curved along their boundaries 21 and have ends facing each other, which in this embodiment are connected. The central wall 28 is preferably configured and dimensioned to cooperate with the main sole portion to support the central portion of the foot and cushion the pressure thereof without damage, in this case the heel portion of the foot.

The walls 28 and 19 themselves carry the majority of the load exerted on the gasket 10. It is therefore preferred that air or other material in the pad 10 is not relied upon to support or relieve pressure on the foot. The walls 28 and 19 of the liner provide the majority of the support by virtue of the liner. Although air or other material may be trapped in the pad, it is most preferred that no trapped material provide substantial support or cushioning.

The insert 10 also has a recess 30 extending between the central portion 26 and the tubular portion 24. The recesses 30 connect the central portion 26 and the tubular portion 24 while isolating vertical deformation between the tubular walls 19 and the central wall 28 adjacent the recesses 30.

As shown in FIG. 3, the tubular wall 19 has vertically spaced ridges 32, while the central wall has vertically spaced ridges 34. The term elevation in this context, including the upper and lower portions of the wall, does not relate only to the top of the liner. Because the ridge 32 of the tubular wall 19 is isolated from the ridge 34 of the central wall 28, substantially no vertical compression is transmitted between them through the valley 30.

Referring again to fig. 2, the gasket 10 also includes a connecting portion 36 having at least one wall that rises from the horizontal portion of the recess 30 and preferably from the isolated recess 30 of the gasket 10. The connecting wall 36 connects the central bulged section 34 with the tubular bulged section 32. The connection connects adjacent ridges 32 and 34 such that vertical deformation is transmitted between the tubular wall 19 and the central wall 28.

When the cushion 10 is impacted at the central portion 26 or the tubular portions 18 or 20 adjacent the connecting portion 36, the connecting portion 36 allows energy to be stored or absorbed and returned to the foot through the central wall 28 and the tubular walls 18 and 20. The location of the connecting portion 36 is preferably selected to be near the common impact area of the sole, so that cushioning is improved. When the insert is positioned in the heel of the sole, the connecting portion 36 is preferably positioned at the rear of the heel, generally in alignment with the heel strike area 52, as is known in the art and as will be described below.

As is well known in the art, when walking, and particularly when the wearer is running, the wearer's foot impacts the sole of the shoe generally along an impact path 66 as shown in FIG. 4. The impact path 66 along the sole is S-shaped and extends from the heel to the forefoot of the sole foot 82. This track 66 is the first to carry the maximum impact load to the sole. The heel strike area 52 is the area within the heel of the sole that is also known to be the strongest impact the wearer's foot first receives.

The insert is positioned in the sole as shown in fig. 2 such that the heel strike area 52 is located in the area defined behind lines 54 and 56. In a preferred insert 10 for a men's shoe size of 9.5 yards, the lines 54 and 56 intersect the centerline 38 of the insert 10 at about 23 to 31mm from the rear of the insert 10. This distance varies depending on the size of the shoe. The line 54 extends laterally outwardly at an angle 58 of about 25 forward from a horizontal line 60 perpendicular to the centerline 38. The angle 58 is preferably 12 ° to 36 °, for example between about 20 ° to 30 °, and the angle 58 is preferably 25.5 °. Line 56 extends medially behind line 60 at an angle 62 of about 5. Angle 62 is preferably between about 0 and 25, such as between 1 and 10, and angle 62 is preferably 4.5. Thus, the connecting portion 36, which is generally centrally disposed relative to the heel strike area 52, is located laterally of the centerline 38.

Because both the central portion 26 and the tubular portion 24 are hollow, the central portion 26 defines a central lumen 40, while the tubular portion 24 defines a tube lumen 42. The central lumen 40 and the tube lumen 42 communicate with each other inside thereof through the connecting portion 36. In the preferred embodiment, tubular wall 19 and central wall 28 communicate between internal chambers 40 and 42 at junction 36 to transfer vertical deformation therebetween. In another embodiment, however, the chambers 40 and 42 may be internally separable, if desired. Still, in another embodiment, the central wall 28 and the tubular wall 19 may be filled with a flexible material, such as foam rubber, gel or other material commonly used for shoe soles.

The central wall 28 and the tubular wall 19 also preferably include ribs 44 that extend transversely across the central portion 26 and the tubular portion 24. It should be noted that the ribs 44 are omitted from fig. 3 for clarity. Since the walls 19 and 28 of the insert 10 of the illustrated embodiment are substantially uniform in thickness, the ribs 44 form channels 46 on opposite sides of the walls 19 and 28. Each rib 44 increases the bending stiffness of the walls 19 and 28. As the ribs 44 are closer to each other, made thicker, and extend further from the rest of the surface of the walls 19 and 28, the walls 19 and 28 become stiffer. The ribs 44 are preferably between about 1-4mm wide and about 6-18mm apart.

Although the ribs may be oriented parallel to one another, it is generally preferred that the ribs extend in a direction perpendicular to the running impact trajectory 66 shown in FIG. 4. The ribs 44 of the illustrated embodiment are oriented at an angle 68 of less than about 40 deg., and more preferably at an angle of less than about 20 deg., from a line 70 normal to the impact path 66.

As shown in FIG. 1, the bottom central wall 28 preferably includes a setback 64 that is substantially as deep as the ribs 44. Therefore, the ribs 44 do not extend beyond the indented portion 64. In another embodiment, additional outsole material may be secured to the indentations 64, or the indentations 64 may be used to display decorative or commercial indicia. Fig. 2 illustrates that the indented portion 64 has a generally elliptical shape. In another embodiment, there is no indented edge printing, and instead there is an edge printing formed by the raised surface of the center wall.

Fig. 3 most clearly illustrates a preferred cross-sectional shape of the gasket 10 taken along the plane III-III of fig. 2 transversely and perpendicularly through the gasket 10. Both the central wall 28 and the tubular wall 19 have an arcuate shape. The central wall 28 preferably defines an oval cross-section, and most preferably an elliptical cross-section, although other shapes, such as angular, are also suitable. The oval shape may be circular, elliptical, or other elongated shape with generally rounded ends, which may also be comprised of a plurality of line segments forming generally rounded ends.

The preferred cross-sectional shape of the tubular wall 19 is generally circular compared to the cross-section of the central wall 28. Due to these shapes, the pad 10 stores energy and returns it to the wearer. The relatively wide horizontal raised portion 34 of the central wall 28 makes the central portion less stiff than the tubular portion 24. The central portion 26 reaches a maximum width 74 at the widest portion of the heel-like cushion 10, which is preferably greater than 50% of the maximum width 84 of the cushion 10 from the inner edge of the medial tubular portion 18 to the outer edge of the lateral tubular portion 20, and more preferably about 60% of the maximum width 84 of the cushion 10. One of the inner and outer tubular portions 18, 20 has a width that is at least about 15%, and more preferably about 20%, of the central portion 26 at the widest point of the cushion 10.

Additionally, in the preferred embodiment, the central portion 26 and the tubular portions 24 have substantially the same vertical height 72. The aspect ratio of each pad section 18 and 20 is defined as the ratio of the width 74 and 75 of each pad section 24 and 26 to its height 72. The aspect ratio of the tubular portions 18 and 20 is measured across their central axis. The maximum aspect ratio of the central portion 26 is between about 2 and 3, preferably about 2.6. The aspect ratio of the tubular portion 24 is between about 0.75 and 1.5, preferably about 1, along the inner and outer sides of the cushion 10. The presence of a higher stiffness of the tubular portion 24 compared to the central portion 26 is desirable because it allows the foot to remain stable toward the central portion 26 during impact. Since the central wall 28 deforms more vertically than the tubular walls 19 during an impact, the cushion 10 directs the foot toward the central portion 26 during each stride to reduce the chance of injury.

Referring to fig. 5, the front portion of the insert 10 includes the central wall 28 and the tubular wall 19, with a rounded front edge 76. The rounded edge 76 facilitates longitudinal bending of the central portion of the sole during walking. In addition, since the lower rear surface 78 of the gasket 10 is angled upward from the horizontal by an angle 80 of about 10 °, the rear end thereof becomes thinner in the vertical direction. This angle 80 allows the heel of the outsole to be raised upward to enhance comfort while the wearer is running.

The insert 10 of fig. 5 has a rib 156 at the horizontal periphery of the tubular wall. The liner 158 of fig. 6, on the other hand, has no ribs, and the grooves 46 extend completely around the exterior of the respective tubular portions.

The liner 10 is preferably blow molded as a unitary structural member. Polyester rubber HYTREL HTR5612 or HTX8382, designed for blow molding and sold by Dupont, is the preferred material for constructing the cushion 10. Other materials well suited for blow molding the gasket 10 have a relatively high melt viscosity. The most preferred gasket material preferably has a Poisson's ratio of about 0.45, a flexural modulus of about 124MPa, and a durometer D rating of 50. When subjected to a compression test for 48 hours, the material is compressed to 50% of its original thickness and then released, preferably with substantially complete decompression of the material. Preferred HYTREL materials have a recovery loss after compression testing of no more than 1% of the original thickness. The remaining portions of the midsole, outsole and insole secured to the midsole and disposed adjacent the foot are made of conventional materials. The primary sole portion 50 preferably has an EVA primary sole 12 and an outsole 14, the primary sole 12 being made of ethyl vinyl acetate and the outsole 14 being made of sponge rubber, transparent rubber and hard rubber.

With these preferred materials, the preferred thickness 152 of the heel pad wall is between about 1.4mm and 2.4mm to support and cushion the heel with the rest of the sole without damage. The thickness may be reduced or increased depending on the mobility of the shoe being manufactured. The thickness may vary depending on the local stiffness requirements within a single pad. The preferred height 160 of the insert is between about 60% and 95% of the height 162 at the sole insert, and most preferably between about 80% and 85%.

As a result of the blow molding process, the hollow stub 48 remains so that air is blown through it during the manufacturing process. The stub 48 is preferably sealed to prevent the cushion 10 from emitting a loud noise each step of the process due to air being drawn in and out through the stub. The sealing stub 48 also prevents water or other fluids that may be present on the road surface from entering the cushion 10. If the stub 48 itself is not closed, the stub opening can be closed with the adjacent material of the main sole portion 50 of the sole. As described above, once the stub 48 is closed, the cushion 10 traps air, but the walls 19 and 28 of the cushion 10 can provide the primary support and cushioning for the foot in place of the trapped air. Even with entrapped air, it is desirable not to impart too much pressure.

Referring to fig. 7-9, a right foot sole of another embodiment of the present invention is shown including medial and lateral cushions 86 and 88 disposed in a forefoot region 90 of a sole 92. Forefoot cushions 86 and 88 are disposed in main sole portion 94, main sole portion 94 including an outsole 96 and a midsole layer 98, outsole 96 including an impact pad 97, disposed beneath forefoot cushions 86 and 88, the midsole layer may be composed of one or more layers, preferably of foam rubber. Forefoot cushions 86 and 88 may also be located at different depths in main sole portion 94, such as entirely in midsole layer 98 or under outsole 96, but are most preferably disposed under midsole layer 98 and also adjacent to outsole 96. The preferred thickness 154 of the forefoot cushion wall is approximately 1-2mm as in the previous embodiments to prevent damage from running impacts or impacts to the footwear during manufacturing. In the case of soles without a cushion in the heel, the cavity in which the cushion would otherwise be located could be damaged during a stride, although in another embodiment, the midsole material is hard enough to prevent damage to the cavity, although no cushion is provided. The preferred height 125 of the forefoot pad wall is between about 30% and 80% of the main sole portion height 164 of the pad, and most preferably between about 40% and 50%.

As shown in figures 10-12, the forefoot cushions 86 and 88 are each preferably a unitary structural member having front and rear hollow elongated tubular portions 100 and 102. The tubular portions 100 and 102 preferably have resilient load-bearing walls 104 and 106 which, as best shown in figure 9, have an oval cross-section along the length or a plane running longitudinally through the shoe and sole. Each web 108 defines a recess, a central portion 110 connecting the tubular portions 100 and 102 therebetween, and also has a generally oval cross-section along a plane extending longitudinally through the sole 94. The tubular portions 100 and 102 extend toward each other on both sides of the central portion 110. The walls 112 of the central portion 110 are also preferably resilient, load-bearing. Also, the blow molded stub 48 shown in the embodiment of FIGS. 1-5 is preferably severed and closed in the forefoot and heel cushions 86, 88, 126 of the embodiment of FIGS. 7-13, although stubs may also be present in alternative embodiments.

The forefoot cushions 86 and 88 are shown disposed in preferred areas 144 and 146, which together form a larger sole area 148 that is at least a metatarsal region of the sole of the foot and that corresponds to and underlies the area of the wearer's foot, which is in place in the sole 94 and held in place by the sole 94 and upper 95 connected to the sole 94. The preferred foot region includes the distal ends of the metatarsals. The thickness, material and shape of the walls 104, 106 and 112 are preferably selected to provide sufficient strength to support and cushion, in conjunction with the main sole portion, both sides of the foot on the tubular walls 104, 106 and the central portion of the foot on the central wall 112, with the forefoot cushions 86 and 88 positioned under the foot. Although the described load bearing walls are preferred, the cushion in this embodiment may alternatively have a plurality of flexible walls that are capable of withstanding a sufficiently large pulling force to contain a fluid such as a liquid, gel or gas to provide the necessary cushioning. The front tubular portion 100 is preferably disposed under the phalanges of the foot.

At least one, and preferably both, of the tubular portions 100 and 102 have a bend 103 that curves around the boundary 105 of the central portion 110 toward its opposing tubular portion 100 and 102, and thus extends along the third side of the sole regions 144 and 146. Although reference is made to the sides of the area, which may be rounded in other embodiments, there may alternatively be corners between the sides. Each of the tubular portions 100 and 102 is preferably defined as at least forming a U-shape, and preferably has a constant height, or a height that varies in a streamline manner, preferably less than 80% of its length, although other tubular shapes, such as tubular portions having a longitudinal undulating cross-section, are also suitable. In other embodiments, the height and width may vary to a greater degree, but preferably the tubular portions 100 and 102 should have smooth, elongated outer surfaces. In the medial pad 86, the third side is preferably the medial side 114 of the distal metatarsal head. In the lateral pad 88, the third side is preferably the lateral side 116 of the distal metatarsal head. Most preferably, the front and rear tubular portions 100 and 102 extend along at least a portion of the third side. The central portion 110 of the medial pad 86 is preferably positioned below the distal most metatarsal at the ball of the thumb to cushion that portion of the foot during a stride, including storing energy and returning it to the foot.

The medial and lateral cushions 86 and 88 are disposed together in the larger sole area 148 as described above, preferably beneath all of the metatarsals. The third sides 144 and 146 are disposed outboard and inboard of the larger area 148. The larger area 148 is longer longitudinally anteroposteriorly near the medial side 114 than near the lateral side. The inner side preferably extends between 40% and 70%, more preferably about 50%. Accordingly, the medial pad 86 is preferably larger than the lateral pad 88 to better accommodate the large metatarsal ends in the medial pad 86. The front and rear edges of regions 144 and 146 are located at the front and rear edges of larger region 148. The anterior and posterior tubular portions 100 and 102 of the medial forefoot cushion 86 are generally aligned with the anterior and posterior tubular portions 100 and 102 of the lateral forefoot cushion 88. The tubes preferably have an axial direction that intersects the medial/lateral direction of the sole 94 at an angle of less than 50.

In a preferred embodiment, tubular portions 100 and 102 are vertically stiffer than central portion 110. The tubular walls 104, 106 are preferably provided with a profile that increases vertical stiffness. Thus, tubular walls 104, 106, like the walls of heel cushion 10, preferably have a higher curvature or have a smaller cross-sectional aspect ratio than central wall 112, although the aspect ratio of tubular portions 100 and 102 of forefoot cushions 86 and 88 is preferably higher than the aspect ratio of tubular portions 18 and 19 of heel cushion 126, resulting in the shape of the sole plate. Thus, the distal metatarsal ends compressed on one of the forefoot pads 86 or 88 are stabilized toward the central portion 110 and remain in the proper area of the sole 94.

Each lateral groove 118 extends through sole 94 in the medial/lateral direction above forefoot cushion 86 or 88 of main sole portion 98. Beneath forefoot cushion 86 or 88, a respective groove 117 is also defined, traversing outsole 96. These sipes 117 and 118 increase the flexibility of the front and rear portions of the sole 94 in the larger sole region 148, thereby forming increased flexibility 119 and decreased flexibility 121 of the sole 94. In a preferred embodiment, the plurality of outsole grooves 117 on the bottom of the outsole 96 converge into a recessed area 150, which also increases local flexibility.

In addition to increasing flexibility in the horizontal plane in which the cushions 86 and 88 lie, each forefoot cushion 86 or 88 also has a thinned region 120 on the third side, preferably between the front and rear tubular portions 100 and 102, for increasing vertical flexibility. The tubular portions 100 and 102 are preferably spaced apart at the thinned area 120 and are not connected to any component of the unitary construction of the cushions 86 and 88, but may be connected to a web or member having a greater resiliency, height or thickness that is substantially less than the tubular portions, preferably less than half of its height. The weakened section may also be formed by making a slit through a continuous U-shaped tubular portion as shown in the embodiment of fig. 1-5. This slit can thus separate the front and rear portions of the tubular portions 100 and 102. The thinned region can also include an elongated tubular portion connecting the tubular portions.

The web 108 between the tubular portions 100 and 102 and the central portion 110 has a height 123 that is much smaller than the height 125 of the tubular and central portions 100, 102 and 110, as shown in fig. 9. In a preferred embodiment, the thinned region 120 extends substantially the entire width 122 of the tubular portions 100 and 102 to intersect an extended centerline 124 of the groove 108 to facilitate bending of the pads 86 and 88 about the thinned region 120 and groove. This configuration enhances the ability of the sole 94 to flex about the distal metatarsal ends as the toes flex upward during walking or running.

The tubular portions 100 and 102 and the central portion 110 are hollow and enclose cavities 136 and 138. The chambers 136 and 138 are in fluid communication via a tube 140 to facilitate blow molding of the forefoot cushion 86 or 88. The height 142 of the tubes 140 is preferably substantially less than the height 125 of the tubular and central portions 100 and 102 and 110 to maintain the flexibility of the forefoot cushions 86 and 88 through the tubes 140 from the thinned region 120 to the web 108. In another embodiment tube 140 is absent.

The two forefoot cushions may be constructed together as a single piece that may be connected by a web or by respective tubular and central portions 100, 102 and 110 that are formed continuous with one another, such as the single cushion 127 shown in figure 14. The single insert 127 has a central portion 128 and front and rear tubular portions 130 and 132 that occupy substantially the entire larger area 148 of the sole. The gaskets 86 and 88 in the embodiment of fig. 10 are two separate components. Separating the forefoot cushions 86 and 88 by using smaller spaces 134 in smaller sized soles and larger spaces 134 in larger sized soles enables manufacturers to use a single size of forefoot cushion 86 and 88 in a range of shoe and sole sizes.

Many variations and modifications will be apparent to one of ordinary skill in the art. For example, in another embodiment, the tubular portion may be constructed as a separate component from the central portion and secured in place by the midsole, or may be placed in a different area of the sole, or in other orientations in a horizontal or other plane. In addition, the shape, size, location and stiffness of the pads and their components can be varied in the shoe being constructed to accommodate activities other than running, such as table tennis, basketball, striding training and walking. For example, because of the increased forefoot impact when playing basketball, the forefoot cushion is harder than the heel cushion of a footwear for basketball, as compared to a footwear for walking. The two forefoot cushions in the shoe also have different stiffness values compared to each other. For example, the lateral forefoot pad may be stiffer than the medial forefoot pad. All such modifications are contemplated as falling within the true spirit and scope of the following claims.

Claims (26)

1. A liner for a shoe sole, the liner comprising:

a center portion having a resilient load-bearing hollow wall comprising a thickness, material, center portion boundary and shape to provide sufficient strength to cushion the sole region; and

there are first and second tubular portions resiliently bearing first and second tubular walls of sufficient thickness, material and shape to cushion at least a portion of the sole region boundary, the first tubular portion being disposed along a first portion of the boundary of the central portion and the second tubular portion being disposed along a second portion of the boundary of the central portion opposite the first portion, wherein the first portion has a first bend portion bendable along the boundary of the central portion to withstand bending therethrough.

2. The cushion according to claim 1, wherein the second portion has a second bend portion bendable along the central portion boundary opposite the first bend portion to accommodate bending through the second bend portion.

3. The liner of claim 1, further comprising a thinned region between the first curved portion and the second tubular portion, the thinned region facilitating bending of the liner therethrough.

4. The cushion according to claim 1, wherein the first curved portion and the second tubular portion are spaced apart from each other at a thinned region.

5. The cushion according to claim 1, wherein at least one of the first and second tubular portions includes another curved portion that is bendable relative to the central portion about a periphery of the central portion substantially opposite the first curved portion.

6. The cushion according to claim 1, wherein each of the tubular portions is vertically stiffer than the central portion so as to stabilize a portion of a wearer's foot toward the central portion when the foot is supported on the cushion.

7. The liner of claim 1 wherein the tubular wall and the central wall are a unitary construction.

8. The cushion according to claim 1, wherein the cushion includes a web having a height lower than the tubular portion and the central portion and connecting the tubular portion and the central portion.

9. The cushion according to claim 1, wherein the tubular portion and the central portion are configured and dimensioned to cushion a sole region including at least one metatarsal tip region.

10. The cushion according to claim 1, wherein the first and second tubular walls include first and second ridges, respectively, and the central wall includes a central ridge, the ridges of the first and second tubular walls being substantially isolated from the central ridge of the central wall so as to not substantially transmit vertical compression therebetween.

11. The liner as set forth in claim 10 further comprising a recess disposed along a periphery of the central portion, wherein the central bulged portion of the central wall is substantially isolated from the first and second bulged portions of the first and second tubular walls by the recess to substantially isolate vertical compression of the first and second tubular walls from the central wall.

12. The cushion according to claim 1, wherein the central wall includes an upper wall and a lower wall, the upper and lower walls defining a hollow cavity therebetween extending substantially through the middle of the cushion.

13. The cushion according to claim 1, wherein the central portion and the first and second tubular portions are substantially curved.

14. The cushion according to claim 1, wherein the curved portion is curved substantially to its shape along the periphery of the central portion.

15. The insert of claim 1 further comprising a sole having a sole height, the insert being operatively connected to the sole and the insert having a height of between 60% and 95% of the sole height at the insert.

16. A sole for supporting a foot of a wearer, the sole comprising:

a main sole portion; and

at least one insert connected to the main shoe bottom, the insert comprising:

a central portion disposed in an area of the sole and having elastically load bearing hollow walls, the walls having a thickness, material, central portion boundary and shape to provide sufficient strength to cushion the sole area; and

first and second tubular portions having first and second resiliently loaded tubular walls of a thickness, material and shape to provide sufficient strength to cushion at least a portion of the sole region boundary, the first tubular portion being disposed along a first portion of the boundary of the central portion, and the second tubular portion being disposed along a second portion of the boundary of the central portion opposite the first portion, wherein the first portion has a first bend portion bendable along the boundary of the central portion to withstand bending therethrough.

17. The sole of claim 16, wherein the sole region includes a distal metatarsal head region of the sole.

18. The sole of claim 16, wherein the primary sole region includes an increased flexibility portion and a decreased flexibility portion, the decreased flexibility portion being less flexible than the increased flexibility portion, the insert being disposed at the increased flexibility portion.

19. The sole of claim 18, wherein the increased flexibility portion defines a generally laterally extending channel that increases the flexibility of the forward and rearward portions of the increased flexibility portion.

20. The sole of claim 18, wherein the cushion has a thinned region on the third side between the tubular portions, the thinned region being more flexible than the tubular portions and allowing the cushion to bend along a line extending between the tubular portions, the thinned region being disposed adjacent the groove.

21. The shoe sole of claim 16, wherein:

the at least one pad includes first and second pads;

the sole region comprising first and second sole regions adjacent one another and together defining a larger sole region; and

the two pads are arranged with their first bends opposite each other in the larger sole area.

22. The sole of claim 21, wherein the first and second tubular portions of each cushion are generally aligned with the first and second tubular portions, respectively, of the other cushion.

23. The sole of claim 21, wherein the larger sole region is a common distal metatarsal region of the sole, including all distal metatarsal regions of the sole.

24. The sole of claim 16, wherein the insert includes a thinned region between the first and second tubular portions, the thinned region being more flexible than the tubular portions and allowing the insert to flex along a line extending between the tubular portions.

25. The sole of claim 16, wherein:

the main sole portion includes a midsole layer and an outsole; and

the cushion is disposed between the midsole layer and the outsole.

26. A liner for a shoe sole, the liner comprising:

a resilient load-bearing central portion having a central portion boundary, said central portion being resilient and load-bearing to cushion the sole region; and

and first and second tubular portions resiliently bearing first and second tubular walls of a thickness, material and shape to provide sufficient strength to cushion at least a portion of the sole region boundary, the first tubular portion being disposed along a first portion of the boundary of the central portion and the second tubular portion being disposed along a second portion of the boundary of the central portion opposite the first portion, wherein the first portion has a first bend portion bendable along the boundary of the central portion to accommodate bending through the first bend portion and the respective tubular portions are vertically stiffer than the central portion to stabilize a portion of a wearer's foot toward the central portion when supported on the cushion.