WO2009061103A1

WO2009061103A1 - Masai walking footwear

Info

Publication number: WO2009061103A1
Application number: PCT/KR2008/006437
Authority: WO
Inventors: Ki Tae Kim
Original assignee: Ryn Korea. Co., Ltd.
Priority date: 2007-11-08
Filing date: 2008-10-31
Publication date: 2009-05-14

Abstract

A Masai walking footwear includes a midsole having a downwardly convex and circular arcuate shape from a front edge to a rear edge so as to realize heel contact during Masai walking; oval front and rear sensors disposed in the front and rear spaces of the midsole; a shank provided inside the midsole and on top portions of the front sensor and the rear sensor of the midsole, and having a plate or board-like shape that resembles a contour and a curved shape of a footwear sole; an insole attached to a top portion of the midsole, having a bottom coupling protrusion in a bottom thereof which couples with the top coupling recess of the midsole; and an outsole attached to a bottom of the midsole and having a convex and circular arcuate structure from a front edge to a rear edge.

Description

Description MASAI WALKING FOOTWEAR

Technical Field

[1] The present invention relates to Masai walking footwear, and more particularly, to a footwear sole including a midsole and an outsole. Background Art

[2] More modern people are developing obesity problems owing to irregular diet, increased intake of fast food and insufficient exercise. This phenomenon is gradually spreading throughout the world, thereby becoming a cause of a variety of cancers and adult diseases.

[3] In order to solve this obesity problem, balanced diet and regular exercise are necessary. While exercising to reduce fatness requires a great amount of time, many modern people have little time to steadily and regularly exercise due to busy lives.

[4] Recently, in order to solve this problem, proposed are a variety of functional shoes that provide exercise effects to a user when the user simply walks, wearing the shoes without particularly devoting time to exercise.

[5] Functional shoes currently distributed in the market are generally referred to as

Masai walking footwear or Masai Barefoot Technology (MBT) footwear. The Masai walking footwear can advantageously minimize an impact on joints by distributing walking load across the entire bottom thereof, prevent diseases of the musculoskeletal system, and maintain a correct posture of a reverse S-shape by supporting the waist. In this manner, the Masai walking footwear can correct the improper gait of modern people.

[6] Referring to Korean Patent No. 10-0377822, details of "FOOTWEAR FOR

DYNAMIC, ROLLING WALKING- ACTION" as Masai walking footwear are disclosed.

[7] Below, a brief description will be given of conventional Masai walking footwear with reference to FIGS. 1 through 3.

[8] FIG. 1 is a representation illustrating conventional Masai walking footwear. The conventional Masai walking footwear 100 includes an upper 110 and a sole 180, which includes an insole 120, a midsole 140 and an outsole 160.

[9] FIG. 2 is a representation illustrating a walking process of the conventional Masai walking footwear. In walking, a foot generally carries out a three-phase process on the ground, which includes heel contact 201, heel-to-toe center-of-mass movement phase 202, and taking-off 203, in which the toe pushes against the ground. Through the three phases, a wearer walks by continuously and repeatedly moving right and left feet. [10] When a person wearing the conventional Masai walking footwear walks according to the three-phase process, he/she can feel good when striking the ground and easily and smoothly walk since a sharp impact is not transferred to ankles or joints of the body or legs

[11] In the meantime, a high elasticity shank is provided inside the midsole of the conventional Masai walking footwear. The shank acts to efficiently restore the original shape of the sole, which is frequently deformed by bending and stretching while walking, improve safety in walking, and promote comfortable walking by adding a restoring force of the taking-off phase in walking.

[12] FIG. 3 is a plan view illustrating a conventional shank. The shank 130 has a plurality of slits 131 extending from predetermined points to the leading edge of a forward part to equally divide the forward part into several areas, bead-shaped ribs 132 longitudinally extending in a middle part to reinforce the central waist part and a plurality of through-holes 133 formed adjacent to the ribs 132.

[13] The Masai walking footwear as described above has a downwardly convex and circular arcuate shape without a heel. Since the Masai walking footwear does not transfer an abrupt impact to ankles as well as joints of the body or legs while walking, it can provide a better feeling to a user striking the ground than other types of footwear can do. Disclosure of Invention

Technical Problem

[14] The conventional Masai walking footwear can restore the original shape of the sole and the footwear using the shank inside the midsole, and particularly, restore the original shape of the sole, which is frequently deformed by bending and stretching while walking.

[15] However, since the conventional shank inside the midsole is designed to move forwards and backwards, it may be a cause of preventing the midsole from smoothly moving through the heel contact, center-of-mass movement and taking-off phases in the three-phase walking process. In addition, the three-phase walking process may feel unnatural since the midsole may create a bouncing feeling.

[16] Accordingly, the present invention provides Masai walking footwear having a shank that can ensure easy and smooth three-phase walking consisting of heel contact, center- of-mass movement and taking-off phases without any bouncing feeling from the midsole. Technical Solution

[17] The inventors have found that Masai walking footwear capable of improving walking stability, preventing hydrolysis and enabling three-phase walking without a bouncing feeling can be provided by arranging a front sensor, a rear sensor and waterproof pads in the bottom of a midsole, installing a shank including a front shank, a rear shank and a connecting plate inside the midsole, and thereby completed the present invention based on these findings.

Brief Description of Drawings

[18] FIG. 1 is a cross-sectional view illustrating conventional Masai walking footwear;

[19] FIG. 2 is a cross-sectional view illustrating a walking process of the conventional

Masai walking footwear; [20] FIG. 3 is a plan view illustrating a shank provided inside the conventional Masai walking footwear; [21] FIG. 4 is a cross-sectional view illustrating Masai walking footwear according to a first embodiment of the present invention; [22] FIG. 5 is a perspective view illustrating the Masai walking footwear according to the first embodiment of the present invention; [23] FIGS. 6 through 10 are cross-sectional views illustrating details of the Masai walking footwear according to the first embodiment of the present invention; [24] FIG. 11 is a cross-sectional view illustrating a Masai walking footwear according to a second embodiment of the present invention; [25] FIG. 12 is a perspective view illustrating the Masai walking footwear according to the second embodiment of the present invention; [26] FIGS. 13 through 17 are cross-sectional views illustrating details of the Masai walking footwear according to the second embodiment of the present invention; [27] FIG. 18 is a cross-sectional view illustrating a Masai walking footwear according to a third embodiment of the present invention; [28] FIG. 19 is a perspective view illustrating the Masai walking footwear according to the third embodiment of the present invention; and [29] FIGS. 20 through 24 are cross-sectional views illustrating details of the Masai walking footwear according to the third embodiment of the present invention.

Best Mode for Carrying out the Invention [30] The present invention provides a Masai walking footwear including a midsole, an insole and an outsole.

Mode for the Invention [31] The present invention relates to Masai walking footwear. The invention provides

Masai walking footwear that has a bottom central protrusion formed in the bottom central portion, a rear space formed in rear of the bottom central protrusion, a front sensor formed in a front space in front of the bottom central protrusion and a rear sensor formed in the rear space. [32] The invention also provides Masai walking footwear that has a bottom pad attached to the bottom portion of the rear sensor and waterproof pads attached to both side surfaces of the front sensor, the rear sensor and the bottom pad.

[33] The invention further provides Masai walking footwear that has a shank provided inside the midsole, wherein the shank includes a front shank, a rear shank and a connecting plate connecting the front shank with the rear shank.

[34] Hereinafter, the present invention will be described more fully with reference to the accompanying drawings, in which exemplary embodiments thereof are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[35] FIG. 4 is a cross-sectional view illustrating a Masai walking footwear according to a first embodiment of the present invention, and FIG. 5 is a perspective view illustrating the same Masai walking footwear.

[36] As illustrated in the drawings, the Masai walking footwear 400 includes a midsole

440, which has a downwardly convex and circular arcuate shape from the front edge to the rear edge so as to realize the heel contact of a Masai walking method. The midsole 440 also has a top coupling recess 440a in the top central portion, a bottom central protrusion 440b in the bottom central portion, a front space in front of the bottom central protrusion 440b and a rear space in rear of the bottom central protrusion 440b.

[37] The footwear also includes an oval front sensor 450a disposed in the front space, an oval rear sensor 450b disposed in the rear space and waterproof pads (not shown) attached to both surfaces of the front and rear sensors 450a and 460b.

[38] A shank 430 is provided inside the midsole 440. Preferably, the shank is provided on the top portions of the front sensor 450a and the rear sensor 450b inside the midsole, in the form of a plate or board that resembles the contour and curved shape of the footwear sole. The shank includes a front shank, a rear shank and a connecting plate connecting the front shank with the rear shank.

[39] The footwear also includes an insole 420 attached to the top portion of the midsole, with the bottom of the insole 420 forming a bottom coupling protrusion 420a that couples with the top coupling recess 440a of the midsole. The footwear also includes an outsole 460 attached to the bottom portion of the midsole 440. The outsole 460 has a convex and circular arcuate structure from the front edge to the rear edge.

[40] Referring to FIGS. 6 through 10, details of the Masai walking footwear according to the first embodiment of the present invention will be described in detail.

[41] FIG. 6 is a representation illustrating the midsole according to the first embodiment of the present invention. The midsole is made of polyester or polyurethane having a hardness of from 40 to 60, and has a downwardly convex and circular arcuate shape from the front edge to the rear edge, with the angle of inclination of the heel ranging from 10 to 60 degrees, so as to realize the heel contact of a Masai walking method. Describing the structural features, the top coupling recess 440a is formed in the top central portion, the bottom central protrusion 440b is formed in the bottom central portion, the front space 441a is formed in front of the bottom central protrusion 440b, and the rear space 441b is formed in rear of the bottom central protrusion 440b.

[42] At the hardness of the midsole not exceeding 40, the midsole is too soft to properly act as a support. In contrast, at the hardness of the midsole the same as or greater than 60, the midsole is too hard to properly act as an elastic body.

[43] FIG. 7 is a representation illustrating the front sensor 450a and the rear sensor 450b, which are attached to the front space 441a and the rear space 441b of the midsole, respectively. The front sensor 450a is oval and is made of soft polyester sponge or soft polyurethane sponge. Likewise, the rear sensor 450b is oval and is made of soft polyester sponge or soft polyurethane sponge. The soft sponge of the front and rear sensors has a hardness ranging from 15 to 30.

[44] The front and rear sensors 450a and 450b can be manufactured as being in tight contact with or being bonded via adhesive to the bottom portion of the midsole.

[45] At the hardness of the front and rear sensors not exceeding 15, the sensors are too soft to properly act as supports. In contrast, at the hardness of the front and rear sensors the same as or greater than 30, the sensors are too hard to properly act as elastic bodies.

[46] The rear sensor 450b is attached into the rear space 441b of the midsole 440 and the front sensor 450a is attached into the front space 441a of the midsole 440 so as to increase buffering efficiency due to contraction.

[47] FIG. 8 is a representation illustrating the waterproof pads 451 attached to both surfaces of the front and rear sensors 450a and 450b. The waterproof pads 451 are made up of one material selected from the group consisting of a polyol coating layer, a polyol fabric combined layer, a polyester pad and a polyurethane pad, with the hardness thereof ranging from 40 to 60.

[48] The waterproof pads prevent the front and rear sensors 450a and 450b and a bottom

450c from hydrolysis.

[49] FIG. 9 is a representation illustrating the shank 430 attached to the inside of the midsole 440, in the form of a plate or board that resembles the contour and curved shape of the footwear sole.

[50] The shank 430 has a plurality of slits 431 extending from predetermined points to the leading edge of a forward part to equally divide the forward part into several areas, bead-shaped reinforcing ribs 432 formed in a waist part to extend in the longitudinal direction and a plurality of through-holes 433 formed adjacent to the ribs 432.

[51] The shank 430 of the present invention includes a front shank 430a, a rear shank

430b and a connecting plate 430c. The front and rear shanks 430a and 430b are made of polyvinyl chloride, and the connecting plate 430c connecting the front shank 430a with the rear shank 430b is made of a material the hardness of which is smaller than that of the front and rear shanks 430a and 430b. Preferably, the connecting plate 430c is made of a thin flexible metal sheet or flexible thin synthetic resin.

[52] The shank 430 can be of a unitary structure in which the front and rear shanks 430a and 430b are integrally connected with each other by the connecting plate 430c, or a separate structure in which the front shank can be connected with the rear shank using a fixing member.

[53] With the shank 430 provided inside the midsole, a rolling movement in Masai walking can be naturally coordinated. The front and rear shanks bend in the vertical direction with respect to the connecting plate, which in turn acts as an elastic body in three-phase walking consisting of heel contact, center-of-mass movement and taking-o ff phases. Owing to the elastic function of the connecting plate, rolling in Masai walking is carried out easily and smoothly.

[54] In addition, the shank 430 ensures easy and smooth elastic rolling from the heel to the toe without a bouncy feeling of the sole and positively maintains the original shape of the sole and the footwear, thereby elastically and securely maintaining the shape of the sole.

[55] FIG. 10 is a representation illustrating the insole attached to the top portion of the midsole and the outsole attached to the bottom portion of the midsole. The insole 420 has a structural feature in that the bottom portion of the insole 420 forms the bottom coupling protrusion 420a that couples with the top coupling recess 440a of the midsole. The insole 420 is made of nonwoven cloth, with the hardness thereof ranging from 25 to 30.

[56] At the hardness of the insole not exceeding 25, the insole is too soft to properly act as a support. In contrast, at the hardness of the insole the same as or greater than 30, the insole is too hard to properly act as an elastic body.

[57] The outsole is attached to the bottom portion of the midsole and has a convex and circular arcuate structure from the front edge to the rear edge. The outsole 460 is made of polyester or polyurethane, with the hardness thereof ranging from 70 to 80.

[58] At the hardness of the outsole not exceeding 70, the outsole is too soft to properly act as a support. In contrast, at the hardness of the outsole the same as or greater than 80, the outsole is too hard to properly act as an elastic body.

[59] The outsole 460 has an inclined and curved arcuate structure, with the main angle of inclination of the heel with respect to the ground ranging from 10 to 60 degrees. At the main angle of inclination not exceeding 10 degrees, the rolling movement of the Masai walking footwear is not possible. In contrast, at the main angle of inclination the same as or greater than 60 degrees, the inclination is too steep for a user to have a stable posture when wearing the footwear or standing in the footwear.

[60] FIG. 11 is a cross-sectional view illustrating a Masai walking footwear according to a second embodiment of the present invention, and FIG. 12 is a perspective view illustrating the same Masai walking footwear.

[61] As shown in the drawings, the Masai walking footwear 600 includes a midsole 640, which has a downwardly convex and circular arcuate shape from the front edge to the rear edge, with the angle of inclination of the heel ranging from 10 to 60 degrees, so as to realize the heel contact of a Masai walking method. The midsole 640 has a bottom central protrusion 640b in the bottom central portion, a front space in front of the bottom central protrusion 640b and a rear space in rear of the bottom central protrusion 640b.

[62] The footwear also includes an oval front sensor 650a disposed in the front space, an oval rear sensor 650b disposed in the rear space and a bottom pad 650c attached to the bottom portion of the rear sensor 650b inside the rear space. The footwear also includes waterproof pads (not shown) attached to both surfaces of the front and rear sensors 650a and 660b and the bottom pad 650c.

[63] A shank 630 is provided inside the midsole. Preferably, the shank 630 is provided on the top portions of the front sensor 650a and the rear sensor 650b inside the midsole, in the form of a plate or board that resembles the contour and curved shape of the footwear sole.

[64] The footwear also includes an insole 620 attached to the top portion of the midsole and an outsole 660 attached to the bottom portion of the midsole 640. The outsole 660 has a convex and circular arcuate structure from the front edge to the rear edge.

[65] Referring to FIGS. 13 through 17, details of the Masai walking footwear according to the second embodiment of the present invention will be described in detail.

[66] FIG. 13 is a representation illustrating the midsole according to the second embodiment of the present invention. The midsole 640 is made of polyester or polyurethane having a hardness of from 40 to 60, and has a downward convex and circular arcuate shape from the front edge to the rear edge, with the angle of inclination of the heel ranging from 10 to 60 degrees, so as to realize the heel contact of a Masai walking method. Describing the structural features, the top coupling recess 640a is formed in the top central portion, the bottom central protrusion 640b is formed in the bottom central portion, the front space 641a is formed in front of the bottom central protrusion 640b, and the rear space 641b is formed in rear of the bottom central protrusion 640b.

[67] At the hardness of the midsole not exceeding 40, the midsole is too soft to properly act as a support. In contrast, at the hardness of the midsole the same as or greater than 60 degrees, the midsole is too hard to properly act as an elastic body. [68] FIG. 14 is a representation illustrating the front sensor 650a, the rear sensor 650b and the bottom pad 650c, which are attached to the front space 641a and the rear space 641b of the midsole. The front sensor 650a is oval and is made of soft polyester sponge or soft polyurethane sponge. Likewise, the rear sensor 650b is oval and is made of soft polyester sponge or soft polyurethane sponge. The front and rear sensors have a hardness ranging from 15 to 30.

[69] At the hardness of the front and rear sensors not exceeding 15, the sensors are too soft to properly act as supports. In contrast, at the hardness of the front and rear sensors the same as or greater than 30, the sensors are too hard to properly act as elastic bodies.

[70] The bottom pad 650c is attached to the bottom of the rear sensor 650b and is made of polyester or polyurethane, with the hardness thereof ranging from 40 to 60.

[71] The front and rear sensors 650a and 650b and the bottom pad 650c can be manufactured to be in tight contact with or be bonded via adhesive to the bottom portion of the midsole 640.

[72] The bottom pad 650c reinforces the weak supporting force of the rear sensor to prevent an ankle from being twisted, and thereby enables stable walking.

[73] FIG. 15 is a representation illustrating the waterproof pads 651 attached to both surfaces of the front and rear sensors 650a and 650b and the bottom pad 650c. The waterproof pads 651 are made up of one material selected from the group consisting of a polyol coating layer, a polyol fabric combined layer, a polyester pad and a polyurethane pad, with the hardness thereof ranging from 40 to 60.

[74] FIG. 16 is a representation illustrating the shank 630 attached to the inside of the midsole 640, in the form of a plate or board that resembles the contour and curved shape of the footwear sole. The shank 630 has a plurality of slits 631 extending from predetermined points to the leading edge of a forward part to equally divide the forward part into several areas, bead-shaped reinforcing ribs 632 formed in a waist part to extend in the longitudinal direction and a plurality of through-holes 633 formed adjacent to the ribs 632.

[75] FIG. 17 is a representation illustrating the insole attached to the top portion of the midsole and the outsole attached to the bottom portion of the midsole. The insole 620 is made of nonwoven cloth, with the hardness thereof ranging from 25 to 30.

[76] At the hardness of the insole not exceeding 25, the insole is too soft to properly act as a support. In contrast, at the hardness of the insole the same as or greater than 30, the insole is too hard to properly act as an elastic body.

[77] The outsole 660 is attached to the bottom portion of the midsole and has a convex and circular arcuate structure from the front edge to the rear edge. The outsole 660 is made of polyester or polyurethane, with the hardness thereof ranging from 70 to 80.

[78] At the hardness of the outsole not exceeding 70, the outsole is too soft to properly act as a support. In contrast, at the hardness of the outsole the same as or greater than 80, the outsole is too hard to properly act as an elastic body.

[79] The outsole 660 has an inclined and curved arcuate structure, with the main angle of inclination of the heel with respect to the ground ranging from 10 to 60 degrees. At the main angle of inclination not exceeding 10 degrees, the rolling movement of the Masai walking footwear is not possible. In contrast, at the main angle of inclination the same as or greater than 60 degrees, the inclination is too steep for a user to have a stable posture when wearing the footwear or standing in the footwear.

[80] FIG. 18 is a cross-sectional view illustrating a Masai walking footwear according to a third embodiment of the present invention, and FIG. 19 is a perspective view illustrating the same Masai walking footwear.

[81] As illustrated in the drawings, the Masai walking footwear 800 includes a midsole

840, which has a downwardly convex and circular arcuate shape from the front edge to the rear edge so as to realize the heel contact of a Masai walking method. The midsole 840 also has a top coupling recess 840a in the top central portion, a bottom central protrusion 840b in the bottom central portion, a front space in front of the bottom central protrusion 840b and a rear space in rear of the bottom central protrusion 840b.

[82] The footwear also includes an oval front sensor 850a disposed in the front space, an oval rear sensor 850b disposed in the rear space and a bottom pad 850c attached to the bottom portion of the rear sensor 850b inside the rear space. The footwear also includes waterproof pads (not shown) attached to both surfaces of the front and rear sensors 850a and 860b and the bottom pad 850c.

[83] A shank 830 is provided inside the midsole 840. Preferably, the shank 830 is provided on the top portions of the front sensor 850a and the rear sensor 850b inside the midsole, in the form of a plate or board that resembles the contour and curved shape of the footwear sole. The shank includes a front shank, a rear shank and a connecting plate connecting the front shank with the rear shank.

[84] The footwear also includes an insole 820 attached to the top portion of the midsole

840, with the bottom of the insole 820 forming a bottom coupling protrusion 820a that couples with the top coupling recess 840a of the midsole 840. The footwear also includes an outsole 860 attached to the bottom portion of the midsole 840. The outsole 860 has a convex and circular arcuate structure from the front edge to the rear edge.

[85] Referring to FIGS. 20 through 24, details of the Masai walking footwear according to the third embodiment of the present invention will be described in detail.

[86] FIG. 20 is a representation illustrating the midsole according to the third embodiment of the present invention. The midsole 840 is made of polyester or polyurethane having a hardness of from 40 to 60, and has a downwardly convex and circular arcuate shape from the front edge to the rear edge, with the angle of inclination of the heel ranging from 10 to 60 degrees, so as to realize the heel contact of a Masai walking method. Describing the structural features, the top coupling recess 840a is formed in the top central portion, the bottom central protrusion 840b is formed in the bottom central portion, the front space 841a is formed in front of the bottom central protrusion 840b, and the rear space 841b is formed in rear of the bottom central protrusion 840b.

[87] At the hardness of the midsole not exceeding 40, the midsole is too soft to properly act as a support. In contrast, at the hardness of the midsole the same as or greater than 60 degrees, the midsole is too hard to properly act as an elastic body.

[88] FIG. 21 is a representation illustrating the front sensor 850a, the rear sensor 850b and the bottom pad 850c, which are attached to the front space 841a and the rear space 841b of the midsole. The front sensor 850a is oval and is made of soft polyester sponge or soft polyurethane sponge. Likewise, the rear sensor 850b is oval and is made of soft polyester sponge or soft polyurethane sponge. The front and rear sensors have a hardness level ranging from 15 to 30.

[89] At the hardness of the front and rear sensors not exceeding 15, the sensors are too soft to properly act as supports. In contrast, at the hardness of the front and rear sensors the same as or greater than 30, the sensors are too hard to properly act as elastic bodies.

[90] The bottom pad 850c is attached to the bottom of the rear sensor 850b and is made of polyester or polyurethane, with the hardness thereof ranging from 40 to 60.

[91] The front and rear sensors 850a and 850b and the bottom pad 850c can be manufactured to be in tight contact with or be bonded via adhesive to the bottom portion of the midsole 840.

[92] FIG. 22 is a representation illustrating the waterproof pads 851 attached to both surfaces of the front and rear sensors 850a and 850b and the bottom pad 850c. The waterproof pads 851 are made up of one material selected from the group consisting of a polyol coating layer, a polyol fabric combined layer, a polyester pad and a polyurethane pad, with the hardness thereof ranging from 40 to 60.

[93] FIG. 23 is a representation illustrating the shank 830 attached to the inside of the midsole 840, in the form of a plate or board that resembles the contour and curved shape of the footwear sole. The shank 830 has a plurality of slits 831 extending from predetermined points to the leading edge of a forward part to equally divide the forward part into several areas, bead-shaped reinforcing ribs 832 formed in a waist part to extend in the longitudinal direction and a plurality of through-holes 833 formed adjacent to the ribs 832.

[94] The shank 830 of the present invention includes a front shank 830a, a rear shank

830b and a connecting plate 830c. The front and rear shanks 830a and 830b are made of polyvinyl chloride, and the connecting plate 830c connecting the front shank 830a with the rear shank 830b is made of a material the hardness of which is smaller than that of the front and rear shanks 830a and 830b. Preferably, the connecting plate 830c is made of a thin flexible metal sheet or flexible thin synthetic resin.

[95] The shank 830 can be of a unitary structure in which the front and rear shanks 830a and 830b are integrally connected with each other by the connecting plate 830c, or a separate structure in which the front shank can be connected with the rear shank using a fixing member.

[96] FIG. 24 is a representation illustrating the insole attached to the top portion of the midsole and the outsole attached to the bottom portion of the midsole. The insole 820 has a structural feature in that the bottom portion of the insole 820 forms the bottom coupling protrusion 820a that couples with the top coupling recess 840a of the midsole. The insole 820 is made of nonwoven cloth, with the hardness thereof ranging from 25 to 30.

[97] At the hardness of the insole not exceeding 25, the insole is too soft to properly act as a support. In contrast, at the hardness of the insole the same as or greater than 30, the insole is too hard to properly act as an elastic body.

[98] The outsole 860 is attached to the bottom portion of the midsole and has a convex and circular arcuate structure from the front edge to the rear edge. The outsole 860 is made of polyester or polyurethane, with the hardness thereof ranging from 70 to 80.

[99] At the hardness of the outsole not exceeding 70, the outsole is too soft to properly act as a support. In contrast, at the hardness of the outsole the same as or greater than 80, the outsole is too hard to properly act as an elastic body.

[100] The outsole 860 has an inclined and curved arcuate structure, with the main angle of inclination of the heel with respect to the ground ranging from 10 to 60 degrees. At the main angle of inclination not exceeding 10 degrees, the rolling movement of the Masai walking footwear is not possible. In contrast, at the main angle of inclination the same as or greater than 60 degrees, the inclination is too steep for a user to have a stable posture when wearing the footwear or standing in the footwear. Industrial Applicability

[101] The Masai walking footwear of the invention can improve elasticity and restoring force and prevent hydrolysis using waterproof pads and can be applied to the development of Masai walking footwear having excellent functionalities.

Claims

[1] A Masai walking footwear comprising: a midsole having a downwardly convex and circular arcuate shape from a front edge to a rear edge so as to realize heel contact during Masai walking, wherein the midsole includes a top coupling recess in a top central portion, a bottom central protrusion in a bottom central portion, a front space in front of the bottom central protrusion and a rear space in rear of the bottom central protrusion; oval front and rear sensors disposed in the front and rear spaces of the midsole; a shank provided inside the midsole and on top portions of the front sensor and the rear sensor of the midsole, and having a plate or board-like shape that resembles a contour and a curved shape of a footwear sole, wherein the shank includes a front shank, a rear shank and a connecting plate connecting the front shank with the rear shank; an insole attached to a top portion of the midsole, having a bottom coupling protrusion in a bottom thereof which couples with the top coupling recess of the midsole; and an outsole attached to a bottom of the midsole and having a convex and circular arcuate structure from a front edge to a rear edge. [2] The Masai walking footwear according to claim 1, wherein the midsole has a convex curved arcuate shape, with an angle of inclination of a heel ranging from

10 to 60 degrees. [3] The Masai walking footwear according to claim 1, wherein the midsole is made of polyester or polyurethane. [4] The Masai walking footwear according to claim 1, wherein the midsole has a hardness ranging from 40 to 60. [5] The Masai walking footwear according to claim 1, wherein the front sensor is made of soft polyester sponge or soft polyurethane sponge. [6] The Masai walking footwear according to claim 1, wherein the front sensor has a hardness ranging from 15 to 30. [7] The Masai walking footwear according to claim 1, wherein the rear sensor is made of soft polyester sponge or soft polyurethane sponge. [8] The Masai walking footwear according to claim 1, wherein the rear sensor has a hardness ranging from 15 to 30. [9] The Masai walking footwear according to claim 1, further comprising waterproof pads attached to both surfaces of the front and rear sensors. [10] The Masai walking footwear according to claim 9, wherein the waterproof pads are made up of one material selected from the group consisting of a polyol coating layer, a polyol fabric combined layer, a polyester pad and a polyurethane pad. [11] The Masai walking footwear according to claim 9, wherein the waterproof pads have a hardness ranging from 15 to 30. [12] The Masai walking footwear according to claim 1, wherein the front and rear shanks are made of polyvinyl chloride. [13] The Masai walking footwear according to claim 1, wherein the connecting plate of the shank is made of a thin flexible metal sheet or flexible thin synthetic resin. [14] The Masai walking footwear according to claim 1, wherein the insole is made of nonwoven cloth. [15] The Masai walking footwear according to claim 1, wherein the insole has a hardness ranging from 25 to 30. [16] The Masai walking footwear according to claim 1, wherein the outsole is made of polyester or polyurethane. [17] The Masai walking footwear according to claim 1, wherein the outsole has a hardness ranging from 70 to 80. [18] A Masai walking footwear comprising: a midsole having a downwardly convex and circular arcuate shape from a front edge to a rear edge so as to realize heel contact during Masai walking, wherein the midsole includes a bottom central protrusion in a bottom central portion, a front space in front of the bottom central protrusion and a rear space in rear of the bottom central protrusion; oval front and rear sensors disposed in the front and rear spaces of the midsole; a bottom pad attached to a bottom of the rear sensor inside the rear space; a shank provided inside the midsole and on top portions of the front sensor and the rear sensor of the midsole, and having a plate or board-like shape that resembles a contour and a curved shape of a footwear sole; an insole attached to a top portion of the midsole; and an outsole attached to a bottom of the midsole and having a convex and circular arcuate structure from a front edge to a rear edge. [19] The Masai walking footwear according to claim 18, wherein the midsole has a convex curved arcuate shape, with an angle of inclination of a heel ranging from

10 to 60 degrees. [20] The Masai walking footwear according to claim 18, wherein the midsole is made of polyester or polyurethane. [21] The Masai walking footwear according to claim 18, wherein the midsole has a hardness ranging from 40 to 60. [22] The Masai walking footwear according to claim 18, wherein the front sensor is made of soft polyester sponge or soft polyurethane sponge. [23] The Masai walking footwear according to claim 18, wherein the front sensor has a hardness ranging from 15 to 30. [24] The Masai walking footwear according to claim 18, wherein the rear sensor is made of soft polyester sponge or soft polyurethane sponge. [25] The Masai walking footwear according to claim 18, wherein the rear sensor has a hardness ranging from 15 to 30. [26] The Masai walking footwear according to claim 18, wherein the bottom pad is made of polyester or polyurethane. [27] The Masai walking footwear according to claim 18, wherein the bottom pad has a hardness ranging from 40 to 60. [28] The Masai walking footwear according to claim 18, further comprising waterproof pads attached to both surfaces of the front and rear sensors and the bottom pad. [29] The Masai walking footwear according to claim 28, wherein the waterproof pads are made up of one material selected from the group consisting of a polyol coating layer, a polyol fabric combined layer, a polyester pad and a polyurethane pad. [30] The Masai walking footwear according to claim 28, wherein the waterproof pads have a hardness ranging from 15 to 30. [31] The Masai walking footwear according to claim 18, wherein the insole is made of nonwoven cloth. [32] The Masai walking footwear according to claim 18, wherein the insole has a hardness ranging from 25 to 30. [33] The Masai walking footwear according to claim 18, wherein the outsole is made of polyester or polyurethane. [34] The Masai walking footwear according to claim 18, wherein the outsole has a hardness ranging from 70 to 80. [35] A Masai walking footwear comprising: a midsole having a downwardly convex and circular arcuate shape from a front edge to a rear edge so as to realize heel contact during Masai walking, wherein the midsole includes a top coupling recess in a top central portion, a bottom central protrusion in a bottom central portion, a front space in front of the bottom central protrusion and a rear space in rear of the bottom central protrusion; oval front and rear sensors disposed in the front and rear spaces of the midsole; a bottom pad attached to a bottom of the rear sensor inside the rear space; a shank provided inside the midsole and on top portions of the front sensor and the rear sensor of the midsole, and having a plate or board-like shape that resembles a contour and a curved shape of a footwear sole, wherein the shank includes a front shank, a rear shank and a connecting plate connecting the front shank with the rear shank; an insole attached to a top portion of the midsole, having a bottom coupling protrusion in a bottom thereof which couples with the top coupling recess of the midsole; and an outsole attached to a bottom of the midsole and having a convex and circular arcuate structure from a front edge to a rear edge. [36] The Masai walking footwear according to claim 35, wherein the midsole has a convex curved arcuate shape, with an angle of inclination of a heel ranging from

10 to 60 degrees. [37] The Masai walking footwear according to claim 35, wherein the midsole is made of polyester or polyurethane. [38] The Masai walking footwear according to claim 35, wherein the midsole has a hardness ranging from 40 to 60. [39] The Masai walking footwear according to claim 35, wherein the front sensor is made of soft polyester sponge or soft polyurethane sponge. [40] The Masai walking footwear according to claim 35, wherein the front sensor has a hardness ranging from 15 to 30. [41] The Masai walking footwear according to claim 35, wherein the rear sensor is made of soft polyester sponge or soft polyurethane sponge. [42] The Masai walking footwear according to claim 35, wherein the rear sensor has a hardness ranging from 15 to 30. [43] The Masai walking footwear according to claim 35, wherein the bottom pad is made of polyester or polyurethane. [44] The Masai walking footwear according to claim 35, wherein the bottom pad has a hardness ranging from 40 to 60. [45] The Masai walking footwear according to claim 35, further comprising waterproof pads attached to both surfaces of the front and rear sensors and the bottom pad. [46] The Masai walking footwear according to claim 45, wherein the waterproof pads are made up of one material selected from the group consisting of a polyol coating layer, a polyol fabric combined layer, a polyester pad and a polyurethane pad. [47] The Masai walking footwear according to claim 45, wherein the waterproof pads have a hardness ranging from 15 to 30. [48] The Masai walking footwear according to claim 35, wherein the front and rear shanks are made of polyvinyl chloride. [49] The Masai walking footwear according to claim 35, wherein the connecting plate of the shank is made of a thin flexible metal sheet or flexible thin synthetic resin. [50] The Masai walking footwear according to claim 35, wherein the insole is made of nonwoven cloth. [51] The Masai walking footwear according to claim 35, wherein the insole has a hardness ranging from 25 to 30. [52] The Masai walking footwear according to claim 35, wherein the outsole is made of polyester or polyurethane. [53] The Masai walking footwear according to claim 35, wherein the outsole has a hardness ranging from 70 to 80.