Therapautic shock-absorbing shoes

Abstract: Women's high heel shoes and men's shoes are provided with unidirectionally compressible resilient heels and internal cushioning pads that absorb shock forces when the shoes are worn while walking, thereby reducing stress on the wearer's feet and legs and on the shoe heels themselves. The stiffness or compliance of the heels can be selected or adjusted to suit the wishes of the wearer.

Description: This invention relates to footwear. It relates more particularly to women's high-heel shoes, and men's shoes. The following general considerations should facilitate the understanding of the present invention. Women's shoes often have high heels or spike heels of various heights and thicknesses. It is estimated that as many as 59% of all women in the United States wear them regularly because they consider them preferable and more fashionable than flats or shoes with lower heels. However, a recent Gallop survey also shows that among these high-heel shoe wearers, 62% have foot pain, blisters, bunions, corns, calluses or other foot problems. Undoubtedly, as a result, the same survey shows that slightly more than half of those women wear high-heel shoes less often than they did five years ago. We believe that these foot problems are, to a large extent, due to the excessive omnidi-rectional shock forces that are routinely transmitted through the ball and heel portions of the wearer's feet into the spine when she walks wearing a pair of these shoes. More particularly, when one walks barefoot or in flats, the heel and ball of the foot are more or less in the same plane. With each stride, the heel strikes the floor first followed by the ball of the foot and then the toes in a progressive rolling motion. Also, there is relatively large-area contact between the foot and the floor at any given time and little possibility to twist an ankle because the heel bone serves effectively as the unidirectional "heel". As a result, there is a smaller impulse and shock force imparted to the foot each time the foot strikes the floor. A typical high heel shoe, on the other hand, has a heel that is 50 to 76mm long. This means that the heel portion of the wear's foot is supported 50 to 76mm above the ball and toe portions of the foot that rest on by the sole of the shoe. Accordingly, when a woman walks in a pair of high heels, although the heel of each shoe strikes the floor first, there is no progressive rolling motion of the foot as described above. Rather, the foot approaches the floor more vertically, with the heel and sole of the shoe striking the floor almost simultaneously. There is very little redirecting and dissipating of those impact forces as occurs when one wears low heel shoes or flats. At most, the heel may have a lift on top on its lower end that is somewhat resilient, but this lift frequently becomes worn away after a relatively short period of time. Resultantly, each time the wearer steps out, a very strong impulse is transmitted without any directional control via the heel and ball portions of the wearer's foot directly to her ankle and leg sending shock forces in any direction through the shoe structure, thus making foot injuries possible. Also, it is a fact that most high heel shoes, particularly the more fashionable ones, have heels whose ends are quite narrow, i.e. of small area. Consequently, all of the reaction forces developed as a result of the wearer's weight and momentum while walking are concentrated primarily in the narrow heel area of the shoe. Furthermore, the fixed incline of the shoe at the arch required to position the heel and ball portions of the wearer's foot at such different elevations mandates that the area of the shoe sole underlying the ball portion also have a relatively small area. Therefore, the shock forces produced by each football are concentrated also on that part of the wearer's foot and propagated from there into the spine where the shock energy is dissipated in the spinal discs. This stress on the ball of the foot is exacerbated because as soon as the sole of the shoe strikes the floor, the wearer's foot tends to slide down the inclined arch of the shoe so that the ball of the foot impacts the bottom of the shoe, while the toes are jammed against the toe and vamp of the shoe. All of these dynamic effects undoubtedly contribute to the spinal problems and foot problems mentioned at the outset, as well as to ankle pain and leg fatigue suffered by many women who have to walk long distances during the course of their day. Also, of course, the forces concentrated in the heel area of a woman's high heel shoe worn while walking also causes great stress on the heel itself, particularly at the narrow end thereof. Sometimes the heel becomes bent or deformed; in extreme cases, the end of the heel actually breaks off. Men's shoes, in contrast, are not as painful to wear as women's high-heeled shoes, but men's shoes with hard heels impart the same shock forces into the spine and the foot bone structure so as to cause similar medical problems for men. Some of the above dynamic effects are mitigated or avoided by a resilient heel construction disclosed in US-Patent 2 807 100. This known construction comprises, between an upper heel section and a lower heel section, telescopical guiding means and compressible resilient means, the latter means including a piston chamber forming an air cushion, a spring and a readily compressible ring shaped element e.g. from sponge rubber, the three just mentioned units participating in a shock absorbing effect. This known construction, however, is rather complicated and, while being resilient, does not have shock energy dissipating capability. Shock force absorbing or resilient heel constructions comprising guiding means between an upper heel section and a lower heel section and a resilient element, preferently in form of springs are moreover known from US-Patent 2 836 907, French Patent 1 227 004 and German Offenlegungsschrift 1 485 705. The last mentioned publication discloses, within the telescopical guiding means, a plug shaped rubber element as the resilient spring means. It is an object of the present invention to further develop a shoe heel with the features of the preamble of claim 1 in such manner that this heel is relatively easy to manufacture, has shock energy dissipating capabilities, can be easily adjusted to the weight and desire of the wearer and has a pleasent appearance. This object, in accordance with the present invention, is a achieved by the characterizing features of claim 1. Advantageous embodiments are characterized in the claims dependent from this claim. Again, in accordance with the present invention, a shoe is provided with a heel which, by a simple construction, controls the direction and magnitude of the shock forces imparted to the shoe when the heel contacts the ground during walking and which, in a unidirectional way, dissipates the shock energy within the shoe. While the invention has particular application to womens' high heel shoes, it may also be incorporated into the heel of mens' shoes. For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description, taken in connection with the accompanying drawings, in which: Fig. 1 is a sectional view with parts in elevation of one embodiment, of the invention; and Fig. 2 is a sectional view taken along line 7-7 of Fig. 1. Fig. 1 and 2 depict generally at 110 a heel embodiment that incorporates our invention. Heel 110 is mounted to the underside of the shoe upper 112 by means of rivets which project from the top of the heel through appropiate openings in the bottom of the shoe upper, with the rivet heads being flattened so that they do not hurt the wearer's foot. An innersole (not shown) may provided to physically isolate the rivet heads. Heel 110 comprises a rigid, suitably shaped heel block 116 having an axial passage 118 which extends from one end of the block to the other. Positioned at the lower end of passage 118 is the stem 120 a of a wear-resistant heel lift or tap 120. The lift 120 and its stem 120 a can be permanently secured in the passage by an appropriate cement or adhesive. Snugly, but slidably, received in the opposite end of passage 118, is a stem or shaft 122 which projects down from a heel plate 124. The rivets 114 described above originate at that heel plate and when the rivets are anchored to the shoe upper, they anchor the plate 124 flush against the underside of the shoe upper 112. Preferably plate 124 is provided with a jog 124 a at the point of connection to shaft 122 so that the weld bead or headed connection 122 a of the shaft to the plate can be a rightangle connection as shown in Fig. 2. Also as shown there, a notch 116 a can be provided at the upper end of block 116 to provide clearance for jog 124 a . Positioned between the undersurface of plate 124 and the upper surface 116 b of block 116 is a resilient compressive member 126 which has a central opening 126 a to provide clearance for shaft 122 and jog 124 a . That member is connected by a suitable bond 128 to the upper end 116 b of block 116 and, via a similar bond 130, to the undersurface of plate 124 so that the block is anchored to the shoe upper 112, yet is permitted to move elastically and unidirectionally parallel to the axis of block passage 118 so as to obtain all of the benefits described above. Preferably member 126 may be shaped and colored to blend in with the remainder of heel 110. Alternatively, it may be provided with a contrasting color coating so that a prospective customer can distinguish a shoe fitted with one of inventors' therapeutic heels from other shoes which do not possess the advantages enumerated above. To permit the customer to vary or to adjust the stiffness or compressive characteristics of member 126, the member 126 may be supplied with the remainder of heel 110 as a separate member with peel and stick adhesive layers on its upper and lower surfaces. This allows the customer to select a member 126 of the appropriate stiffness when purchasing shoes equipped with heels 110. Alternatively, a single member 126 may be provided which has holes or cutouts as shown in phantom at 134 in Fig. 2. In this event, the heel 118 or shoe would be sold with plugs shown in phantom at 136 in Fig. 2 which fit snugly in the holes 134. These plugs would have different stiffnesses or spring constants so that by inserting the appropriate plugs in holes 134, the pad as a whole can be designed to have compression characteristics suitable for the particular wearer. When the wearer is satisfied with the "feel" or compliance of the shoe equipped with a heel 110, she can strip away the backing strips from member 126 and position the member as shown in Fig. 1 so that when she steps on the heel, the member 126 will become firmly bonded to the heel block 116 and the heel plate 124. While such bonds anchor heel block 116 to the shoe upper 112, the heel block can still move unidirectionally and elastically as described above. If for any reason the wearer desires to change the stiffness characteristics of heel 110 at a later date, the heel block 116 can be pulled away from plate 124 (with some considerable effort), after which the heel block surface 116 b and the plate 124 can be cleaned so that a new compressive member 126 having a different stiffness characteristic can be incorporated into heel 110. Such a change might be desirable, for example, if the wearer gains or loses appreciable weight. It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained.

Claims: A shoe heel (110) comprising an upper heel section (88; 124), a lower heel section (94; 116), unidirectionally compressible connecting means (92, 94a, 96; 118, 122, 126) elastically connecting said heel sections so that the lower heel section (94; 116) can move between a stable extended position and an unstable compressed position, said connecting means (92, 94a, 96; 118, 122, 126) including a) a shaft (94a; 122) having one end mounted to one of the heel sections and extending telescopically into guiding means provided on the respective other of said heel sections and b) a compressible resilient structure (96; 126) located between said heel sections, and comprising a pad from elastically compressible material, surrounding said shaft (94a; 122) and being shaped to match the remainder of the heel; characterized in that said compressible resilient structure is said pad from elastically compressible material, said pad being positioned near the upper end of the heel, and that said shaft (122) is connected to the upper heel section (124) and extends downward through a bore of said pad. A shoe heel as defined in claim 1, characterized in that said shaft (122) is connected to a rigid plate (124) that forms the upper heel section and is provided with means (114) for anchoring said rigid plate to a shoe (10). A shoe heel as defined in claims 1 and 2, characterized in that said pad (126) from elastically compressible material has at least one opening (134) therein and a plug (136) received in said at least one opening (134), said plug (136) having a different stiffness from the remainder of said pad (126). A shoe heel as defined in one of the claims 1 to 3, characterized in that a wear-resistent heel surface (129) is mounted to the lower heel section (116) being spaced from said pad (126) from elastically compressible material. A shoe heel as defined in one of claims 1 to 4, characterized in that said pad (96; 126) is bonded with its upper surface to a lower surface of said upper heel section and is bonded with its lower surface to an upper surface of the lower heel section. A shoe heel as defined in claim 5, characterized in that the upper and the lower surface of said pad (96) from elastically compressible material are provided with peel-and-stick-adhesive layers.

Inventors: KUEHNLE MANFRED R, SENFTNER VIDALA J, KUEHNLE, MANFRED R., SENFTNER, VIDALA J.
Applicants: KUEHNLE MANFRED R, SENFTNER VIDALA J, KUEHNLE, MANFRED R., SENFTNER, VIDALA J.
Application year: 1988
Main classification: A43B21
IPC codes: A43B21