EP0396622B1

EP0396622B1 - High heeled shoe design

Info

Publication number: EP0396622B1
Application number: EP89902140A
Authority: EP
Inventors: Howard J Dananberg
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-01-21
Filing date: 1989-01-20
Publication date: 1994-11-02
Anticipated expiration: 2009-01-20
Also published as: CA1340728C; DE68919212T2; EP0396622A1; WO1989006502A1; EP0396622A4; DE68919212D1; JPH03502415A

Abstract

A high heeled shoe having a heel seat (4) above about 1 3/4 inches and which is inclined upwardly and rearwardly at 1 1/2 degrees plus/minus 1 1/2, a toe support region (7) inclined upwardly and forwardly at 5 1/2 degrees plus/minus 1 degree and a shank (5), joining the heel seat (4) and the toe support region (7), permitting a downward and forward declination of a wearer's first metatarsal of 30 degrees plus/minus 3 degrees to provide a metatarsus to phalanges buttress effect to eliminate toe jamming.

Description

This invention relates to a new and improved design for high heeled pump or fashion shoes. The invention is particularly, though not exclusively, applicable to such shoes having heels in the height of at least one and three-quarter inches preferably in the range of one and three-quarters to two inches or more.
Prior art high heeled shoes in current use have a reputation of being extremely uncomfortable and there is survey information indicating that as many as 20% of the users of such shoes experience foot pain related to the shoes immediately and the majority of users experience such pain after as little as four hours of use. This discomfort results from the wearer's foot sliding forwards in the shoe with the consequence that the wearer's toes are jammed in the toe portion of the shoe.
One attempt at reducing the discomfort resulting from the wearing of high heeled shoes is found in U.S. Patent 2,465,817 in which, in the toe portion of the shoe, a concave depression 22 is arranged to receive the ball portion of the wearer's foot and a convex mound portion 24 is provided forward of that concave portion whereby the weight of the wearer is supported mainly, if not entirely, by the ball portion of the foot and by the heel of the foot with the wearer's weight mainly on the ball portion of the foot. Such an arrangement is said to permit very high heels, as high as four inches, without discomfort to the wearer as the ball portion of the foot is received in the concave depression of the shoe thereby preventing the foot from sliding forward in the shoe. As will be seen from this patent, the heel seat proposed in the construction disclosed is at a very substantial angle to the ground plane, that angle being of the order of 45 degrees. As a consequence, very little of the wearer's weight will actually be supported by the heel seat with the wearer's weight, as stated above, being carried mainly on the ball portion of the foot. This results in excessive weight being borne by the metatarsal with the likelihood that there will be excessive pressure on the head of the metatarsal resulting in metartarsalagia. In any event this design will result in substantial discomfort and a reduction in foot flexibility.
Other examples of prior art will be found in U.S. Patents 1,693,398, 2,254,353, 2,370,789, 2,641,066, 2,852,865, 4,631,841 and RE 18,237.
It is an object of the present invention to provide a comfortable high-heeled pump or fashion shoe capable of being used for extended periods without discomfort.
This object is achieved by a high heeled shoe as defined in the independent claims 1 and 6.
The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a diagrammatic cross sectional view of a high heeled shoe according to the present invention; and
Figure 2 is a diagrammatic representation showing a comparison of relevant angles to the ground plane of a shoe according to the present invention such as that shown in Figure 1 and current high heeled shoes having similar heel heights.

With reference to Figure 1 there is shown in ghost the bone structure of a foot. This structure comprises the tarsus 1, the metatarsus 2 and the phalanges 3. The tarsus 1 is supported by the heel seat 4 while the metatarsus extends over the shank 5 to the ball of the foot 6 where the metatarsus joins the base of the phalanges 3. The ball of the foot underlying the heads of the metatarsals, forming the metatarsus, and the phalanges are supported by the toe region 7 of the shoe.
The shoe illustrated in Figure 1 has a heel height of from approximately one and three-quarter inches to approximately two inches or more. The particular shoe illustrated is based on a U.S. standard ladies' shoe size 7. The shoe is shown on a ground plane 8 from which the heel height to the heel seat 4 is measured. The heel seat 4 may be parallel with the ground plane or inclined upwardly and rearwardly of the shoe at an angle of up to approximately 3 degrees relative to the ground plane and is preferably at an upward and rearward inclination of approximately 2 degrees. This angle is referenced X in Figures 1 and 2. The metatarsus is angled downwardly and forwardly of the shoe from the heel seat with the first metatarsal at an angle of approximately 30 degrees plus/minus 3 degrees relative to the ground plane, preferably at an angle of approximately 30 degrees plus/minus 1 1/2 degrees and more preferably at an angle of approximately 30 degrees. This angle is reference Y in Figures 1 and 2.
In the toe region of the shoe the great toe is inclined upwardly and forwardly by the upward and forward inclination of the toe region at an angle of approximately 5 1/2 degrees plus/minus 1 degree relative to the ground plane. This angle is reference Z in Figures 1 and 2.
In Figure 2 the line in ghost illustrates the heel seat 4 angle X, the inclination Y of the first metatarsal 2 and the great toe spring Z in the toe region 7 relative to the ground plane 8. Dimension U represents the heel height. The solid line in Figure 2 represent the corresponding set of angles and inclination for currently available high heeled shoes having similar heel heights to that proposed for the present invention. In these current shoes the inclination of the heel seat is upward and backwards towards the rear of the shoe at an angle L of approximately 8 degrees, the inclination of the first metatarsal downwardly and forward is at an angle M of less than 27 degrees and the great toe is inclined upwardly and forwardly at an angle N of approximately 1 1/2 degrees. These angles L, M and N are also relative to the ground plane 8 and relate to a shoe of similar size, namely U.S. standard ladies' size 7.
The ranges of angles specified above in the present inventive shoe result in an included angle between the toe support region 7 of the shoe and the center line of the first metatarsal of from approximately 140 1/2 degrees to approximately 148 1/2 degrees.
It is believed that a brief explanation of the mechanics of the foot is appropriate to facilitate an understanding of the function of the shoe of the present invention. The foot is capable of functioning in two separate mechanical fashions so as to support the body above. Primarily, the foot functions as a beam and supports the body by bending strain. This mechanism of support is effective when the force in acting on the arch (arch flattening force) is relatively low. This occurs at such times in the step when the center of body weight falls posterior (behind) the ankle joint. As the center of weight passes ahead of the ankle joint, as occurs in a normal step forward, the forces present begin to cause arch flattening. To counter this, the foot is capable of initiating a basic change in the mechanism of support to a truss form of support and is then capable of supporting via compression strain. Since the bones of the foot have been shown to be extremely strong in terms of compression strength, the greater the compression strain, the better the arch support ability. In order for the foot to achieve this change in support mechanism, the metatarsals must be buttressed by the bending of the toes. This buttress effect prevents the metatarsals from sliding forward and thus permits the switch from bending to compression support.
It is this effect which is taken advantage in the shoe design of the present invention. By creating a particular platform surface for the foot, a buttress effect is initiated in a more effective fashion preventing the forward sliding of the metatarsal bones and, as a result, eliminating the subsequent jamming of the toes into the pointed front of the shoes.
Increasing the angle of bending (extension) of the toes in the shoes can be accomplished in one of two ways, the tip of the shoes may be lifted upwards creating a "genie" type shoe. Although this would be effective, it would not be particularly stylish. A more effective mechanism entails increasing the angle at which the metatarsals themselves approach the sole of the shoe. This has the effect of increasing the bending of the toes without creating a "genie" type shoe. This increase in the angle of the metatarsals relative to the ground plane is accomplished by the change in the rear construction of the shoe (specifically the angle of the heal seat 4). Since the foot is jointed in a variety of locations, the plane that the heel bone (calcaneous) takes with the ground will be compensated for by the pitch of the metatarsals as they approach the ball of the foot. This angular relationship is inversely proportional. The closer the calcaneous comes to parallel with the ground (provided there is adequate heel height present), the closer the metatarsals approach a perpendicular attitude. Thus by providing a heel seat with a low slope to increase the descent angle of the metatarsal, the desired buttressing effect is achieved.
In the present invention, which is directed to shoes having a heel height above about 1 3/4 inches, the heel seat is maintained essentially level (up to 3^o) with respect to the ground irrespective of the heel height. In all previous shoe designs, the higher the heel of the shoe, the greater the inclination toward the ground. This inclination angle increase created an inclined platform of the foot toward the floor. This increased angle forced the foot to slide forward and be pinched in the toe portion of the shoes. The present invention creates a shoe with the relationship of the heel of the shoe parallel to the support surface. The metatarsal angle (corresponding to the shank of the shoe) increases porportionally to the heel height, e.g. the higher the heel, the greater the metatarsal angle to the floor. In a shoe with a heel height over 1 3/4 inches, the advantage is not of increased metatarsal inclination, but rather the resulting biomechanical change in metatarsal inclination due to the maintanance of heel parallel with the support surface.
This effect is emphasized when the toe region is angled as specified above in order to increase the spring angle of the toes. As a consequence of this particular design, the load distribution between the foot and the shoe is effected whereby when the wearer is at rest a greater proportion of the weight of the wearer is borne by the heel seat rather than being transferred by the sloping surface of the prior art shoes to the ball of the foot with consequent problems as referred to above. By the design of the present invention, toe jamming is prevented and comfort assured.
While the description above has been made with respect to a U.S. standard ladies' shoe size 7, the invention is applicable to the whole usual range of U.S. standard ladies' shoe sizes and particularly to those in the range from size 5 to size 10. With different shoe sizes the metatarsal inclination will vary within the range specified with this inclination being close to 33 degrees for a shoe size 5 and nearer to 27 degrees with a shoe size 10. The range of angles for the heel seat and the toe support region given with respect to a size 7 shoe are applicable to shoes in the sizes ranging from 5 to 10.

Claims

A high heeled shoe defining a ground plane (8) and having a heel seat (4) which is at least about 4.4 cm (1 3/4 inches) in height above the ground plane (8), said heel seat (4) being disposed at an angle (x) of from approximately 0 degrees relative to said ground plane (8) to an inclination upwardly and rearwardly of approximately 3 degrees relative to said ground plane (8), whereby to prevent jamming of wearer's toes into the toe portion of the shoe, said shoe also having a shank (5) extending forwardly and downwardly from said heel seat (4) to a toe support region (7) extending forward of the shank, the downward extension of the shank (5) permitting the first metatarsal (2) of a person wearing the shoe to be inclined downwardly and forwardly at an angle (m) of from approximately 27 degrees to approximately 33 degrees relative to the ground plane (8).
A high heeled shoe according to claim 1 wherein the toe support region (7) is inclined upwardly and forwardly at an angle of from approximately 4 1/2 degrees to approximately 6 1/2 degrees whereby the included angle between said first metatarsal (2) and the toe support region (7) is from approximately 140 1/2 degrees to approximately 148 1/2 degrees.
A high heeled shoe according to claim 2 wherein the heel height is from approximately 4.4cm (1 3/4 inches) to approximately 5cm (2 inches).
A high heeled shoe according to claim 3 wherein the heel seat (4) is inclined upwardly and rearwardly at an angle (x) of approximately 2 degrees relative to the ground plane (8).
A high heeled shoe according to claim 4 wherein said first metatarsal (2) is inclined downwardly and forwardly at an angle of approximately 30 degrees relative to the ground plane (8) and the toe support region is inclined upwardly and forwardly at an angle (y) of approximately 5 1/2 degrees relative to the ground plane.
A high heeled shoe having a heel of at least about 4.4cm (1 3/4 inches) high above a ground plane (8), a heel seat (4) topping said heel, a shank (5) extending forwardly and downwardly from the heel seat to a toe support region (7) extending forward of the shank (5), the heel seat (4) being disposed at an angle of between approximately 0 degrees relative to said ground plane (8) to an inclination upwardly and rearwardly of approximately 3 degrees relative to said ground plane (8) so as to prevent forward sliding of the foot of that person relative to the shoe, whereby to prevent jamming of the wearer's toes into the toe portion of the shoe, the downward extension of said shank (5) permitting the first metatarsal (2) to be inclined downwardly and forwardly at an angle of from approximately 27 to approximately 33 degrees relative to the ground plane (8).
A high heeled shoe according to claim 6 wherein the toe support region (7) has an inclination upwardly and forwardly to augment the amount by which the metatarsus (2) is buttressed by the phalanges (3).
A high heeled shoe according to claim (6) wherein said angle of the heel seat (4) is an upward rearward inclination of approximately 1 1/2 degrees plus/minus 1 1/2 degrees.
A high heeled shoe according to claim 8 wherein the declination (y) of the toe support region (7) is approximately 30 degrees plus/minus 3 degrees.
A high heeled shoe according to claim 7 wherein said inclination is approximately 5 1/2 degrees plus/minus 1 degree.
A high heeled shoe according to claim 10 wherein said angle (x) of the heel seat (4) is an upward rearward inclination of approximately 1 1/2 degrees plus/minus 1 1/2 degrees and wherein said declination (y) is approximately 30 degrees plus/minus 3 degrees.