US3496584A - Shoe and shoe last - Google Patents

Description

Feb. 24, 1970 v A; L. ll EATl -l snow AND SHOE LAST '4 Sheets-Sheet 1 Filed Nov. 22, 1968 FIG-2 INVENTOR. ARTHUR L- HEATH ATTORNE YS Feb. 24, 1970 A. L. HEATH SHOE AND SHOE LAST 4 Sheets-Sheet 2 Filed Nov. 22, 1968 INVENTOR. ARTHUR L- HEATH ATTORNEYS Feb. 24; 1970 A. 1.. HEATH 3,

SHOE AND SHOE LAST 4 Sheets-Sheet 5 Filed Nov. 22, 1968 Feb. 24, 1970 A. L. HEATH 3,496,534

' SHOE AND SHOE LAST Filed Nov. 22, 1968 4 Sheets-Sheet 4 INVENTOR. ARTHER L. HEATH F I W ATTORNEYS United States Patent US. Cl. 12-133 6 Claims ABSTRACT OF THE DISCLOSURE A shoe last and shoe are improved for better foot posture by asymmetrically curving the heel seat so the inner curve rises to a higher level than the outer and extends forward to a point just posterior to the inside ball point, tilting the heel portion outward at the top, and twisting the cone portion so that the top tilts outward at the rear and inward at the front to direct Weight supporting propulsive forces toward the inside ball region. The resulting top center line of the contours of the last is outside the vertical central reference plane at the heel, crosses the reference plane in the cone region, and angles inside the reference plane towards the inside ball region.

EVOLUTION OF THE INVENTION This invention is an improvement in a line of development shown in US. Patents #2,160,991 and #2,716,294. These teachings were based on a study of the bone and muscle structure of the ankle and foot together with precise recording and analysis of the' critical timing in the sequence of contraction and relaxation of the several muscles which control the function of the foot, and the resulting proposals made improvements in shoes and shoe lasts that have been valuable advances in the art. The #2,160,991 patent taught the curving of the undersurface of the heel and cone regions downward and outward to form an asymmetrically curved insole in the heel and shank regions of the shoe. This was also a successful improvement over ordinary, straight-up shoes.

The present invention proposes that instead of tilting the top of the cone area of the last outward, that the top of the heel region of the last he tilted outward and that the cone region be twisted from the outward tilt of the heel to an inward tilt leading toward the inside ball region. This departs from the suggestion of the #2,716,294 patent and builds upon the basic feature of the #2,160,991 patent. The result is a shoe that conforms more naturally to the foot, promotes better foot posture and growth, and conforms the shoe more accurately to the cuboid stream and scaphoid stream of the foot bones. The inventive modification was reached through continued study and experimentation with the prior art improve ments.

The objects of the invention include, without limitation, a shoe that is readily made on existing equipment and helps guide the foot in a natural walking posture for optimum distribution of supportive and propulsive forces during each step and for maximum comfort and freedom from excessive stress on the muscles, ligaments and tendons of the foot and leg. These and other objects of the invention will be apparent hereinafter from the specification which describes the invention, its use, operation, and preferred embodiments, from the drawings which constitute a part of the disclosure, and from the subject matter claimed.

SUMMARY OF THE INVENTION The inventive shoe last is describable relative to a vertical reference plane which contains the bisector of the last, a longitudinal axis on the reference plane, and nineteen evenly-spaced contours on planes normal to the 3,496,584 Patented Feb. 24, 1970 axis and to the reference plane and consecutively numbered from the toe to the heel of the last, and the inventive shoe has a shape complimentary to such last. The inventive last is configured so that the bottom surfaces of its heel and shank portions are asymmetrically curved, the inner portion of the curve rising higher than the outer portion and so that a line joining the top center of its contours lies outside the reference plane in the region of contours 18-13, crosses the reference plane in the regions of contours 1240, and angles inwardly away from the reference plane toward the region of the inner ball point. This is the most convenient way of defining the inventive tilting of the heel region and twisting of the cone or shank region.

The drawings:

FIG. 1 is a medial side elevation of the inventive shoe last for a right shoe;

FIG. 2 is a lateral side elevation of the inventive shoe last for a left shoe;

FIG. 3 is a plan view of the shoe last of FIGS. 1 and 2; and

FIGS. 4-8 are polar charts showing the contours of the inventive last of FIGS. 1-3.

DETAILED DESCRIPTION Some conventions are used in describing and defining the inventive shoe last and shoe, and these will be described before the specific shape of the inventive last is described. Of course, other conventions or descriptive techniques can be used, and the invention is embodied in lasts and complimentary shoes and not the particular descriptive convention used to explain the inventive shape. The lasts 30 and 30a of FIGS. 1 and 2 show right and left lasts respectively to illustrate both the medial and lateral sides of the last. The conventions used in defining the inventive last are the same for either a right or left last so the distinction can be ignored.

The inventive last 30 is positioned as shown in FIG. 1 on surface 31 with its heel elevated by pin 32 to the correct heel height, and verticals 33 are arranged tangent to the widest parts of the heel and forefoot portions of the last to project points 33 on surface 31 directly below the sides of the last. Two lines 34 and 35 (FIG. 3) are then drawn tangent to the last through the marked points 33 at the widest part of the forefoot and heel portions set by verticals 33. Tangent lines 34 and 35 diverge at an acute angle as shown in FIG. 3. A line 36 bisecting the angle between lines 34 and 35 is then constructed, and a vertical plane containing line 36 forms a vertical bisector reference plane for last 30.

The longitudinal axis of the last 30a in the reference plane is located with last 30a resting on surface 31 as shown in FIG. 2. The distance from toe point 37 to surface 31 is measured up the heel of last 30a to locate point 38. Points 37 and 38 are each in the reference plane above bisector line 36, and the last is supported between points 37 and 38 for turning to develop its contours.

By convention, 19 contours are numbered from the toe toward the heel of the last with the 0 countour tangent to the toe point and the 20 contour tangent to the heel. Each of the contours of the last is then perpendicular to the reference plane and to the longitudinal axis of the last extending between points 37 and 38. The contours are plotted on polar charts as shown in FIGS. 4-8 to define the cross-sectional shape of the last at each contour plane. The contour planes are numbered alongside line 35 in FIG. 3, and the contours are successively illustrated in FIGS. 468. Of course, different numbers or construction of contours can be used.

A new concept called a top center line helps define the inventive last simply and clearly. The top center line 3 40 for last 30 is shown in FIG. 3, and it is constructed this way. The contours in the cone and forefoot portion of the last from contour 13 forward to the inner ball region each have a top point located by the intersection between the contour line and a horizontal tangent line at the top of the contour. In the shank and forefoot portions of the last, the top center line extends through the top points of each contour, forward to the region of the inner ball point of the last in the area of contours 6-7. Forward of the ball region, the contours are relatively fiat on top, and the top center line is not significant. The tops of contours 13 to 19 have the flat shape conventional it the heel of the last so that a tangent line would not accurately establish the top center of the last. For such contours the top center is approximated by the center points of such fiat portions so that in the heel region, the

top center line connects the centers of the flat tops of each contour. Hence, the expression top center line is used to refer to the line connecting the centers of the flat portions of the heel contours 19-13 and the top points of cone contours from contour 12 forward to the ball reglon.

The inner or medial ball region of the last is generally inside the reference plane, near the forward end of top center line 40 in FIG. 3, and in the region of contours 6-7. The inner ball point is generally at the base of the great toe and is approximately 60% to 66% of the way forward from the heel to the toe of the last, depending on the styling of the toe portion of the last.

With the above-described conventions, the inventive last is fully defined in FIGS. 3-8. The contours of FIGS. 4-8 show successive cross-sectional shapes of the inventive last from the heel forward to contour as viewed from the heel. The toe of the last from this point forward is conventional in shape and styled as desired. Of course, the invention also includes shoes having a shape complimentary to the claimed iast.

Each contour has a respective inclination line identified by the number of the contour followed by the letter a to help illustrate the inclination of each contour relative to the vertical reference plane. The inclination lines extend between the longitudinal axis at the center of the polar chart and the top writer or top point of each respective contour. For example, superposed inclination lines 17a, 18a and 19a extend from the center of the polar chart of FIG. 4 to the top center of contours 17, 18 and 19 respectively.

The contour inclination lines show that the heel portion of the last in the region of contours 19-13 is inclined outward at its top by from two degrees to five degrees from the vertical reference plane. Also, the cone portion of the last starts with the outward inclination of the heel at contour 12 and twists inward to an inward inclination leading toward the inner ball region. Thus, the top of contour 12 is inclined outward, contour 11 approaches the vertical, contour is upright, and contours from contour 9 forward are inclined increasingly inwardly.

The same information is shown by top center line 40 in FIG. 3 which lies outside the vertical reference plane in the region of contours 19-13, revealing the outward inclination of the tops of such contours, and which turns inward to cross the vertical reference plane in the region of contours 11-12 and inclines inwardly toward the ball region of contours 5-7, revealing the twisting of the cone region. The included angle a between the forward portion of the top center line 40 and the vertical reference plane is from 17-23 degrees to conform to the weight-bearing bones extending from the ankle forward to the first metatarsal head. The angle or varies somewhat with heel height. The twisting of the Cone area of the last is shown by the .4 curve in top center line 40 which bends between contours 13 and 10 to turn inward and cross the vertical reference plane.

The asymmetrical curvature of the bottom surfaces of the heel and shank portions of the last from the inside downwardly to the outside is shown 'by the bottoms of contours 19-8 of FIGS. 4-7. Insoles of shoes made according to the inventive curve asymmetrically downward and outward under foot. Also, the inventive lasts and shoes generally appear to tilt outward at the top of the heel and then to turn inward with the top center ridge of the shoe and last running obliquely across the vertical reference plane inward to the ball point rather than generally straight forward as in conventional shoes.

Shoes made on the inventive last more effectively resist the normal tendency of the normal foot to pronate due to the lateral displacement of the os calcis relative to the talus. This is especially important in shoes for childrens growing feet. Persons wishing to practice the invention should remember that other embodiments and variations can be adapted to particular circumstances. Even though one point of view is necessarily chosen in describing and claiming the invention, this should not inhibit broader or related applications within the spirit of the invention. For example, other features and style elements can vary the lasts and shoes havng the inventive features.

I claim:

1. A shoe last describable relative to vertical reference plane on the bisector of said last, a longitudinal axis on said reference plane, and 19 evenly spaced contours on planes normal to said axis and said vertical reference plane and consecutively numbered from the toe to the heel of said last, said last being configured so that the bottom surfaces of the heel and shank portions of said last are asymmetrically curved from the inner side thereof downwardly toward the outer side thereof, and a line joining the top centers of said contours lies outside said reference plane in the region of contours 18-13, crosses said reference plane in the region of contours 12-10, and angles inwardly away from said reference plane from said crossing point to the region of the inner ball point of said last.

2. The last of claim 1 wherein said top center line from said crossing point to said ball region forms an included angle with said reference plane of from 17 degrees to 23 degrees.

3. The last of claim 2 wherein the included angle between said reference plane and lines joining said axis and said top center line in contours 18-13, is from 2 degrees to 5 degrees.

4. The last of claim 1 wherein the included angle between said reference plane and lines joining said axis and said top center line in contours 18-13, is from 2 degrees to 5 degrees.

5. The last of ciaim 1 wherein said top center line is curved in the region of said crossing point.

6. A shoe having a shape complimentary to the last of claims 1, 2, 3, 4, or 5, and wherein the insole of said shoe in the heel and shank regions of said shoe is asymmetrically curved from the inner side thereof downwardly toward the outer side thereof.

References Cited UNITED STATES PATENTS 1,952,685 3/1934 Sabeletal. "12-133 2,309,775 2/1943 Levitt 12- 133 2,733,463 2/1956 Mascioli 12 133 PATRICK D. LAWSON, Primary Examiner U.S. C1.X.R. 36-25

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