Shoe construction providing spring action

Abstract: A shoe for running, cross training and the like includes a base member (12) including a raised front portion and a rearwardly extending rear portion. A U-shaped spring (14) is disposed beneath the raised portion. The spring has transversely extending ends engaging the front portion at respective longitudinally spaced locations. The front end of the spring is preferably unconnected to the raised portion such that a projection on the latter cams against and flattens the spring when the user's weight is put on the raised portion. A sole spring element (16) is affixed to the front portion of base member and includes a flexible part (16b) overlying, and extending rearwardly beyond, the sole portion of the base member. The flexible part of the rear spring element (16b) is disposed at an acute, non-zero angle with respect to the sole portion (12b) of the base member.

Description: Field of the Invention The present invention relates to an improved shoe construction which is particularly useful as a running shoe, training shoe or the like. Background of the Invention In general, running or walking involves a specific pattern or sequence of events insofar as the foot is concerned. In particular, the heel impacts the ground first, the weight then shifts forward onto the ball of the foot and next the forefoot and toe region provide the last contact with the ground as the foot is lifted from the ground. The initial impact in the heel area is of special interest with runners because, in general, it is desirable to absorb as much impact energy as possible, consistent with providing a stable landing and without slowing down the runner. A further consideration in a shoe construction of this type is that of actually enhancing the performance of the wearer by, e.g., providing built-in spring force that facilitates the weight shift mentioned above and also assists in propelling the foot off the ground. A number of patents relate to shoe constructions which are variously designed to address one or more of the issues discussed above. For example, U.S. Patent Nos. 5,596,819 and 5,437,110 (Goldston, et al.) disclose an adjustable shoe heel spring and stabilizer device for a running shoe including a spring mechanism disposed in the midsole of the shoe and including a cantilevered spring member and an adjustable fulcrum therefore. U.S. Patent No. 4,492,046 (Kosova) discloses a running shoe which includes a spring wire located in a longitudinal slot in the shoe extending from the back edge thereof into the arch region. U.S. Patent No. 2,447,603 (Snyder) discloses a U-shaped spring plate disposed between the heel of the shoe and overlying a rear portion of the shoe sole. Other U.S. patents of possible interest include: 2,444,865 (Warrington); 3,882,490 (Murawaski); 4,592,153 (Jacinta); 5,343,636 (Sabol); 5,435,079 (Gallegos); 5,502,901 (Brown); 5,511,324 (Smith); 5,517,769 (Zhao); and 5,544,431 (Dixon). AT-B-387695 discloses a shoe in which the sole is defined by front and rear portions, with the front portion having a flap hinged to the front of the rest of the sole, and a spring between the flap and the part of the sole above the flap. The spring then biases the flap downwardly. FR-A-909691 discloses a shoe in which the sole has a curved part on which the foot rests and a flat part to rest on the ground. The flat part is privately attached to the curved part at an intermediate portion along the length thereof and connected to the curved part by springs at its ends. Summary of the Invention According to a first aspect of the invention there is provided a shoe construction comprising: a base member including a raised front portion and a rearwardly extending rear portion, at least said front portion including a rigid part; a spring member, formed by a flat elongate spring element, affixed to said base member and disposed beneath the front portion of said base member so as to extend longitudinally along said base member and a foot receiving portion affixed to said base member characterised in that: the spring member is substantially U-shaped such that opposite ends of said spring member abut against said rigid part of said front portion so that said spring member compresses and rolls forwardly in response to the application of downward pressure on said front portion exerted during use by a foot of a weaver, and the construction further comprises a spring element extending rearwardly from the base member above the rear portion of the base member the spring element being disposed at an acute non-zero angle with respect to the rear portion of the base member. Advantageously, the spring member further comprises a support shell which is secured to the front portion of said base member and in which the U-shaped spring is slidably received so as to permit removal of the spring. The support shell preferably includes first and second, longitudinally spaced, transversely extending rails against which the free ends of the U-shaped spring engage. The base member preferably includes a curved portion located between the front portion and the sole portion for enhancing shifting of the weight of a wearer to the ball of the foot. Advantageously, the sole portion of the base member is covered with a bottom sole. The bottom sole preferably comprises a perforated subsole having a plurality of spaced perforations therein and a porous underlayer covering the perforated subsole. Preferably, the rear portion of the spring element is of greater flexibility than the front portion of the spring element. The rear portion of said spring element is advantageously comprised of a flexible graphite material which resists side to side torsion, and the front portion of the spring element is comprises of a graphite composite. Advantageously, the acute angle between the flexible rear portion of said spring element and the sole portion of the base member is a value which lies between 20° and 25°. Preferably, the distal end of the rear portion of the spring element extends beyond the distal end of the rearwardly extending sole portion of the base member. In an advantageous implementation, the distal end of the rear portion of the spring element is located at a spacing of between 7,62 to 8,89 cm above the distal end of the rearwardly extending sole portion. Advantageously, a reinforcement member is disposed between the rear portion of the spring element and the rearwardly extending portion of the base member. A mounting means is preferably provided for removably mounting the reinforcement member on said rear portion of the spring element. The mounting means advantageously comprises a plurality of spaced support straps affixed to the rear portion of the spring element. A cushion element is preferably disposed at the distal end of said rear portion of said spring element. A retaining strap is advantageously affixed to said sole portion of said base member and extending around said rear portion of said spring element. The retaining strap preferably includes an openable fastener. In addition, the shoe construction advantageously further comprises a retaining strap means affixed to the front portion of the base member and extending above the front portion of the spring element for receiving the front part of the foot of a wearer. When the spring member has a rear end portion connected to the base member a front end portion in unconnected engagement with the front end portion of the base member, the base member preferably includes a downwardly projecting element and it is this element that is in unconnected engagement with the front end portion of the spring member. Advantageously, the base member includes a transitional portion between the front and rear portions thereof and the rear end portion of the spring member is embedded in the transitional portion. In the embodiment wherein the base member includes a transitional portion between the front and rear portions thereof, the spring element preferably includes a first end embedded in this transitional portion. Advantageously, the base member includes an upper surface including laterally spaced ridges and the foot receiving portion is affixed to the surface between the ridges. Preferably, the foot receiving portion is further affixed to spring element. Preferably, an elastomeric sole is affixed to a bottom surface of the rear portion of said base member. Other features and advantages of the invention will be set forth in, or apparent from, the following detailed description of preferred embodiments of the invention. Brief Description of the Drawings Figure 1 is a side elevational view of a shoe construction in accordance with one preferred embodiment of the invention; Figure 2(a) to 2(e) are schematic side elevations of basic elements of the shoe construction of the invention illustrating sequential stages in landing and lifting of the shoe and showing the spring action provided thereby; Figure 3 is a side elevational view, partially broken away, of a shoe construction in accordance with a further preferred embodiment of the invention; and Figure 4 and 5 are a schematic side elevational view and bottom plan view, respectively, of a yet another embodiment of the invention. Description of the Preferred Embodiments Referring to Figure 1, an exemplary embodiment of the shoe construction of the invention is shown. It should be understood that the illustrated embodiment is simply one example of a suitable overall shoe construction and the basic elements and principles of the invention, which are described more generally in connection with Figures 2(a) to 2(e), have general application. In this regard, the invention can, for example, be incorporated in a more conventional looking running shoe if desired. In the illustrated embodiment, the shoe construction or shoe, which is generally denoted 10, includes a base member 12 including a raised, rigid front or sole support portion 12a, and an integral rigid subsole portion 12b stepped down from the front portion 12a and extending rearwardly therefrom. Base member 12 is preferably made of a rigid carbon graphite with an aluminum rod support, or of a like material and construction. A bowed, flexible spring member 14 is disposed beneath, and secured to, front portion 12a of base member 12. In a preferred embodiment, a small lip 12c (e.g., of extent) is provided at the toe of base member 12. As illustrated, spring member 14 is disposed substantially directly under the ball of the foot and extends between the front of front portion 12a to a rear part of front portion 12a adjacent to a curved portion 12d of subsole 12b. The curvature of curved portion 12d is such as to enhance shifting of the weight of a wearer to the ball of the foot during running or walking as described in more detail below. The spring member 14 is preferably made of spring steel, flexible carbon graphite or the like. In a preferred embodiment shown in Figure 1, spring member 14 is of a two piece construction comprising a support shell or support housing 14a of an inverted, squared off U-shape and a spring 14b of a bowed or shallow generally U-shape. The ends of support shell 14a form two longitudinally spaced, transversely extending rails and support shell 14a is preferably constructed, e.g., of aluminum. As illustrated, the free ends of spring 14b engage against, but are not secured to, the respective rails formed by shell support 14a. With this construction, spring 14b can be slid in and out of shell 14a to enable replacement or substitution. Spring 14 preferably extends across the full width of the shoe 10 although the spring 14 can be more narrow if desired. Secured to the front portion 12a of base member 12 is a sole spring element 16. Sole spring element 16 includes a front portion 16a which is preferably comprises of a non-flexible graphite composite, which is affixed to the front portion 16a which is preferably comprises of a non-flexible graphite composite, which is affixed to the front portion at 12a of base member 12 and on which rest the toes and ball of the feet of a wearer. Sole spring element 16 further includes a rear portion 16b which is preferably comprised of a flexible graphite material that resists side to side torsion, and which extends rearwardly of front portion 16a at an acute, non-zero angle with respect to subsole 12b. In a specific, non-limiting example, rear portion 16b forms an angle between bout 20° and 25°, and preferably of about 22°, with subsole 12b, and the distal end of rear portion 16b is located about 7,62 to 8,89 cm above the plane of the ground. Although this height is advantageous, other heights can be used and, in general, a height of between about 1 and 6 inches could be workable. As illustrated, the distal end portion of sole spring element 16 extends a substantial distance beyond subsole 12b. A supplementary, and optional, reinforcement member 18 is located between sole spring element 16 and subsole 14b, and, in the illustrated embodiment, is supported beneath sole spring element 16 by a series of spaced support straps or loops 20 secured to the undersurface of element 16. Alternatively, reinforcement member 18 can be received and held in a longitudinal groove or channel (not shown) formed in the bottom surface of rear portion 12b or can be affixed, at the front end thereof, to the front portion 12a of base member 12, e.g., by being secured in place in a slot or recess in front end portion 12a in a cantilever fashion. Reinforcement member 18 is preferably made of spring steel, flexible carbon graphite or the like. Reinforcement member 18 is preferably removable and can be replaced with a similar member having different characteristics, e.g., one providing additional spring force or one providing variable spring action because of the shape or construction thereof. In the illustrated embodiment, an overlay, indicated 22 and made of rubber or the like, is provided on the upper surface of sole spring element 16, and a cushion element 24 of rubber or the like is provided at the distal end or heel portion of sole spring member 16. In a preferred embodiment indicated schematically in Figure 1, the subsole 26, which is made of a rigid, light material, is of a perforated or grate-like construction including a plurality of perforations or holes 26a therein and is covered by a porous rubber bottom member or underlayer 26b. This enables water, and air, to rise up through the underlayer 26b into the holes 26a when the wearer is running on a wet surface to thereby prevent hydroplaning and increase the aerodynamics of the shoe. In the embodiment shown in Figure 1, an open strap assembly 28, comprising a pair of transverse, U-shaped straps 28a interconnected by longitudinally extending connector straps 28b made of Nylon or the like, is affixed to the front portion 12a of base member 12 for gripping the front of the foot of a wearer. A further, single elongate strap 30, including a buckle fastener 30a, is adapted to fit around the wearer's foot just in front of the ankle. The spring action provided by shoe 10 can perhaps be best appreciated by reference to Figures 2(a) to 2(e) wherein the basic elements of the shoe construction, viz., base member 12, spring 14, sole spring element or member 16, and optional reinforcement member 18, are shown. Figure 2(a) illustrates the relative positions of these members when the foot F of a wearer is lifted above the ground G and, in this instance, is about to land on the ground (the movement of the foot F being indicated by arrow A). As shown in Figure 2(b), as the shoe 10 hits the ground and the full weight of the wearer is received by, i.e., is brought to bear on, the shoe 10, the weight is first received by curved portion 12d and subsole 12b. Further, the rear portion 16b of spring element 16 begins bending backward to form an arch as indicated in Figure 2(b). As a consequence, a whipping action is created as the weight of the wearer is shifted to the ball of the foot. Spring portion 16b thus accelerates lifting of the heel from the ground and propels the weight of the wearer forward to the ball of the foot where curved portion 12c acts as a pivot or fulcrum about which the weight is shifted to the front spring 14 and thus accelerates the movement of the foot in leaving the ground. In general, spring 14 is not involved until the weight of a wearer shifts or rolls forward. Spring 14 is designed and constructed such that compression thereof begins only when more than one half of the body weight of the wearer is transferred thereto. As shown in Figure 2(c), as the weight of wearer shifts forward to the ball of the foot as indicated by arrow F1, spring 14 is compressed and subsole 12b tips off of the ground G. As discussed above, as the force on the spring element 16 is released, the weight of the wearer is shifted to the front of the shoe 10 and the shoe 10 rolls forward on curved portion 12d and on spring member 14 until sufficient weight is transferred to cause spring member 14 to collapse or compress. At this point, both the heel of the foot and the subsole 12b are off of the ground because of the rolling or pivoting action around curved portion 12d. Before the wearer begins to lift his or her foot, the weight of the wearer compresses spring 14. As the foot is lifted and weight is removed from spring 14, this spring provides a lifting force, indicated by arrow S2, on the ball area of the foot. Finally, as shown in Figure 2(e), all spring forces return to the initial states thereof i.e., the states of Figure 2a, when the shoe 10 is fully lifted from the ground G. In a further alternative embodiment, a coil spring or another additional spring element (not shown) could be added in the space created within spring 14, i.e., between spring 14 and the lower surface of front portion 12a, to provide further spring force as needed. Referring to Figure 3, there is shown a shoe constructed in accordance with a further preferred embodiment of the invention. The shoe of this embodiment, which is generally 40, includes a base or frame member 42 including a raised, rigid front or sole support portion 42a and an integral rear or heel portion 42b which is stepped down from front portion 42a and extends rearwardly therefrom. Base member can be fabricated of a rigid plexiglass material or another suitable material. A spring 44 in the shape of a shallow U is affixed at one end to heel portion 42b of base member 42. In a preferred embodiment, the other end of spring 44 is biased into contact with, but not affixed to, a downwardly projecting element 42c of front portion 42a. In other words, spring 44 is in unconnected engagement with projecting element 42c. With this construction, projecting element 42c rides along and cams against the facing portion of this end of spring 44 as the weight of the user is placed on the front portion 42a. This construction enables an increased range of movement of spring 44 and provides an increase in effective return spring force as compared with a spring construction such as that shown in Figure 1 wherein both ends of the spring are fixed to the shoe. The size and length of spring 44 is increased as compared with spring 14 of Figure 1 and, in this regard, spring 44 extends from the front of shoe 40 to a location near, or even rearwardly of, the middle of the shoe 40. Spring 44 can be constructed of reinforced carbon graphite or other suitable materials. A sole member 46 preferably fabricated of rubber of the like is affixed to the flat bottom surface of rear portion 42b of base member 42. A further spring or spring element 48 is affixed at one thereof to base member 42 in the transitional area 42d between front portion 42a and rear portion 42b. Spring element 48 serves a function similar to spring element 16 of Figure 1. Spring element 48 is formed of a simple flat member but can alternatively be shaped to conform to the shape of the bottom surface of the shoe upper 50. Spring element 48 can be constructed of carbon graphite or another suitable spring material. Shoe upper 50 is affixed to the upper surface of spring element 48 and to the upper surface of front portion 42a of base member 42 between laterally spaced side rails, one of which denoted 42e, is shown in Figure 3. Shoe upper 50 can, of course, take a number of different, more or less conventional, forms, and the overall appearance of the shoe 40 can also be made to be more like a conventional shoe. Referring to Figures 4 and 5, there is shown, in a highly schematic manner, yet another embodiment of the invention. This embodiment is similar to that of Figure 3 and like elements have been given the same reference numerals. In the embodiment of Figures 4 and 5, a further spring 51 is included which is similar to spring 44 but is nested within the latter in spaced relation thereto, as shown in Figure 4. The forward end of spring 51 engages, but is not connected to, a downward projection 42f formed on base or frame member 42. Spring 51 includes a plurality of spikes or cleats 52 along the length thereof. Spring 44 includes a plurality of apertures of holes 54 therein which are arranged to register with spikes 52. Holes 54 are preferably covered by a thin elastomeric (e.g., rubber) membrane or covering 56 (see Figure 4). As bottom spring 44 is compressed, spikes 52 protrude through apertures 54 to provide additional gripping. The spikes 52 deform, but do not penetrate through, membrane 56. The embodiment of Figures 4 and 5 provides variable spring action and, in this regard, both springs 44 and 51 provide lift. It is noted that the retractable-extendable spike arrangement of Figures 4 and 5 could also be applied to a more conventional or traditional running shoe or like shoe. For example, a soft foam or rubber sole can be provided which compresses under the weight of the user (e.g., a runner) so that spikes or cleats are fully or partially exposed so as to grip the ground.

Claims: A shoe construction comprising: a base member (12, 42) including a raised front portion (12a, 42a) and a rearwardly extending rear portion (12b, 42b), at least said front portion (12a, 42a) including a rigid part; a spring member (14,44), formed by a flat elongate spring element, affixed to said base member (12, 42) and disposed beneath the front portion (12a, 42a) of said base member (12) so as to extend longitudinally along said base member and a foot receiving portion (16, 48) affixed to said base member characterised in that : the spring member (14, 44) is substantially U-shaped such that opposite ends of said spring member (14, 44) abut against said rigid part of said front portion (12a, 42a) so that said spring member (14, 44) compresses and rolls forwardly in response to the application of downward pressure on said front portion exerted during use by a foot of a wearer, and the construction further comprises a spring element (16b, 48) extending rearwardly from the base member above the rear portion of the base member (12,43), the spring element being disposed at an acute, non-zero angle with respect to the rear portion of the base member (12, 42). A shoe construction as claimed in claim 1 wherein said spring member (44) has a rear end portion connected to said base member (42) and a front end portion in unconnected engagement with the front end portion (42a) of the base member. A shoe construction as claimed in claim 2 wherein the front end portion (42a) of said base member includes a downwardly projecting element (42c) in unconnected engagement with the front end portion of said spring member (44). A shoe construction as claimed in claim 3 wherein said base member (12) includes a transitional portion (42d) between said front and rear portions thereof and said rear end portion of said spring member (44) is embedded in said transitional portion (42d). A shoe construction as claimed in any one of the previous claims wherein said base member (42) includes a transitional portion (42d) between said front and rear portions and said spring element includes a first end embedded in said transitional portion (42d). A shoe construction as claimed in claim 1 wherein said base member includes an upper surface including laterally spaced rails and said foot receiving portion (50) is affixed to said surface between said rails. A shoe construction as claimed in claim 6 wherein said foot receiving portion (50) is further affixed to said spring element. A shoe construction as claimed in claim 1 further comprising an elastomeric sole affixed to a bottom surface of the rear portion of said base member. A shoe construction as claimed in claim 1 further comprising a further spring member (51) located within said U-shaped spring member (44) and including a plurality of gripping spikes (52) extending downwardly therefrom, said U-shaped spring member (44) including a plurality of apertures (54) therein in registration with said spikes (52) such that said spikes (52) extend through respective apertures (54) when said U-shaped spring member (44) is compressed by the weight of a user.

Inventors: WALLERSTEIN ROBERT S, WALLERSTEIN, ROBERT S.
Applicants: WALLERSTEIN ROBERT S, WALLERSTEIN, ROBERT S.
Application year: 1998
Main classification: A43B13
IPC codes: A43B5, A63B25, A43B13, A43B1, A63B69