Classifications

• • A—HUMAN NECESSITIES
  • A43—FOOTWEAR
  • A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
  • A43B13/00—Soles; Sole-and-heel integral units
  • A43B13/14—Soles; Sole-and-heel integral units characterised by the constructive form
  • A43B13/18—Resilient soles
  • A43B13/20—Pneumatic soles filled with a compressible fluid, e.g. air, gas
  • A43B13/206—Pneumatic soles filled with a compressible fluid, e.g. air, gas provided with tubes or pipes or tubular shaped cushioning members
• • A—HUMAN NECESSITIES
  • A43—FOOTWEAR
  • A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
  • A43B13/00—Soles; Sole-and-heel integral units
  • A43B13/14—Soles; Sole-and-heel integral units characterised by the constructive form
  • A43B13/18—Resilient soles
  • A43B13/181—Resiliency achieved by the structure of the sole

Definitions

• This invention primarily relates to a midsole of an athletic shoe, particularly a running shoe. More specifically, it is directed to a lightweight molded, foamless, shock absorbing mid-sole that will adequately absorb a runner's impact forces and simultaneously provide durability, longitudinal stability and lateral support.
• our invention is a midsole for an athletic shoe. More particularly, it is a molded midsole formed of an elastomer whose ratio of plastic deformation to elastic deformation is greater than 1.5 to 1.
• the elastomer is a copolyester polymer elastomer such as that manufactured and sold by E.I. duPont de Nemoirs under the trademark Hytrel.®
• the midsole takes the shape of a flexible upper layer separated from a lower, ground engaging layer by cylindrical shaped springs that are integrally joined to the upper and lower layers.
• This midsole has a rear-foot section in which the springs are in the shape of a plurality of truncated right cylindrical springs that extend from outside the lateral and medial sides of the shoe to a position underneath the shoe.
• these individual cylindrical springs are not continuous, but are interrupted underneath the rear-foot section, and in conjunction with the lower layer, define a circumferential support surface that extends around the rear-foot section.
• the midsole of our invention also includes mid-foot section as well as a fore-foot section. As will be shown, the cylindrical springs incorporated into rear-foot and the fore ⁇ foot sections are unique and fully provide the desired energy absorption, longitudinal and lateral support.
• the objectives of this invention are to provide, inter alia,
• Figure 1 is a perspective view of a running shoe
• Figure 2 is a plan view of the preferred embodiment of the midsole of this invention.
• Figure 3 is a sectional side elevation view of the preferred embodiment of the invention, the view taken along the lines 3-3 of figure 2;
• Figure 4 is a perspective view of the preferred embodiment of the bottom of midsole of this invention.
• Figure 5 is an elevational view taken along the lines 5-5 of figure 8;
• Figure 6 is another side elevation view of a preferred embodiment depicting the invention in the flexed position
• Figure 7 is a side elevational view of the rear-foot section of a "preform" of our invention.
• Figure 8 is a side elevational view of the rear-foot section of the invention after it has been compressed to eliminate compression set of the plastic material.
• FIG. 1 Such includes a running shoe 10 with an upper 12 that completely covers the foot and has the usual eyelets and lacing 14 on the top with a multilayered sole 20.
• the multilayered sole 20 comprises the preferred embodiment of the midsole invention.
• this midsole is divided into three sections along its longitudinal axis. These sections include a rear-foot section 24, a mid-foot section 26 and a fore-foot section 28. These sections and the entire midsole are molded as one integral piece. Preferably, they are injection molded with an elastomer having tensile characteristics such that the ratio of plastic strain to elastic strain is greater than 1.5 to 1.
• One such elastomer is a copolyester polymer elastomer manufactured and sold by E.I. du Pont de Nemoirs under the trademark Hytrel.® It is reasonably inert and significantly, it is quite durable.
• this elastomer is not subject to tear propagation even when made in relatively thin cross sections.
• the midsole 20 of this invention includes a generally flat top ply or layer 32 of elastomeric material from which depends generally cylindrical springs 34 that are integrally joined to a flat ply or bottom layer 36 as shown in figures 3 and 4.
• the top layer 32 is also directly joined to the bottom layer 36 at the front 33 of the midsole 26, at the mid-foot section 26 and at the rear 35' of the midsole as shown in figure 3.
• the cylindrical springs 34 are preferably truncated, right cylinder sections. These springs 34 need not and do not extend completely across the rear-foot section 24. Instead, these springs 34 are positioned in a generally U-shaped configuration about the circumference of the rear-foot section, leaving a void or recess 40 in the center of the rear-foot. The void and the resulting elimination of material provides substantial weight reduction. Significantly, the recess 40 and the weight reduction is permitted by the selected material and the manufacturing process described herein.
• the illustrated interconnections of the upper layer 32 and the lower layer 36 provide excellent longitudinal stability.
• the outward extensions 35 of the cylindrical springs 34 beyond the circumference of the upper 12 provides a wider platform for the runner's foot.
• these design of these extensions 35, their length and the direction of the cylinder sections 34 is used, in part, to control the "roll" of the runner's foot.
• the wall thickness of the cylindrical springs 34 of the rear-foot section is thicker on the medial side of the shoe than on the lateral side. This increased thickness is also used to provide the desired control of the motion of the foot.
• the extension of the recess or void section 40 from the rear-foot section into the fore-foot section also provides torsional flexibility to the midsole and to the shoe.
• the forward extension of this recess is permitted since the strength of the material around the circumference of the shoe is more than adequate.
• Support for the fore-foot section of the midsole is also provided by cylindrical springs as shown in figures 3,4 and 6.
• These springs 42 have a construction that is slightly different from the cylindrical springs 34 of the rear-foot section.
• the springs 42 extend across the entire width of the midsole.
• they are slightly tapered from the medial to the lateral side of the shoe, i. e. . the cross sectional thickness of the cylinder walls is greater on the medial side.
• the cylinder springs of the fore ⁇ foot section are slit as at 44. As best illustrated in figure 6, this slit along the bottom surface of the cylinder spring and the midsole provides substantial, added flexibility to the fore-foot. Indeed, as the foot rolls farther forward, the cylinder sections 34 are permitted to open and enhance the flexibility of the shoe.
• the midsole 20 is preferably injection molded.
• the Hytrel® material will take a compression set.
• our invention is molded into a preform, and is subsequently compressed to take that set.
• compression of the Hytrel® material not only causes the material to take a set, the compression also results in orientation of the molecular structure and enhances the spring characteristics of the material.
• the information of that patent is incorporated herein by reference.
• Figure 7 illustrates this taller preform that has been molded but not compressed. After the preform has been removed from the mold and allowed to coil and stabilize for up to twenty-four hours, it is then compressed, preferably to a solid position. Upon release of the compressive force, the upper and lower layers 32 and 36 will partially spring back, leaving the cylindrical springs 34 in an oval configuration as shown in figure 8. The midsole takes a "set” in this position. Thereafter, these springs 34 may be partially compressed during use by the runner, but as his weight is removed, the springs will return to the "set" oval position shown in figure 8.

Landscapes

• Footwear And Its Accessory, Manufacturing Method And Apparatuses (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)

Priority Applications (1)

Applications Claiming Priority (3)

Related Child Applications (1)

Publications (3)

Family

ID=22687331

Family Applications (2)

Family Applications Before (1)

Country Status (5)

Cited By (6)

Families Citing this family (19)

Citations (3)

Family Cites Families (12)

• 1995
  • 1995-01-10 AT AT95907374T patent/ATE206885T1/de not_active IP Right Cessation
  • 1995-01-10 DE DE69523288T patent/DE69523288T2/de not_active Expired - Lifetime
  • 1995-01-10 AU AU15627/95A patent/AU1562795A/en not_active Abandoned
  • 1995-01-10 WO PCT/US1995/000334 patent/WO1995020333A1/en active IP Right Grant
  • 1995-01-10 EP EP98111671A patent/EP0877177A3/de not_active Withdrawn
  • 1995-01-10 EP EP95907374A patent/EP0741529B1/de not_active Expired - Lifetime

Patent Citations (3)

Non-Patent Citations (1)

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