User-specific shoe sole coil spring system and method of assembling the shoe

Abstract: A user-specific shoe sole coil spring system (10) provided as a customized layout of individual coil springs which are seated in a shoe sole cushion (12) having prefabricated circular depressions (14) on its surface. The coil spring system layout and stiffness characteristics may be customized to serve the needs of different users and different applications. A user's weight and particular comfort and/or orthopedic requirements are met in a given shoe size by fitting it with a greater or lesser quantity of springs with different levels of stiffness, or the layout may be a combination of levels. The result is a shock absorption distribution patterns and energy return system for the shoe sole cushion (12) to suit the requirements of a particular application. The sole cushion (12) has a cover strip (17) overlaying the coil spring system (10) which is openable and reclosable for allowing changes in the layout as required, or an entire sole cushion (12) may be replaced as a unit.

Description: The present invention relates to a two-part shoe construction, and to a method of assembling it. This invention relates more particularly to a novel coil spring system for a shoe featuring a user-specific, customized layout for various areas of the shoe sole, applicable to athletic, working and walking shoes, or to other activities associated with a particular group. The prior art includes various shoe constructions in which a spring is applied to a shoe sole for shock absorption and energy return during walking or running. Examples of these designs include that shown in U.S. Pat. No. 4,843,737 to Vorderer, in which two outwardly curved plates having a tensioning spring are placed in the heel of an athletic shoe, to store and return energy to a runner while providing shock absorption. U.S. Pat. No. 4,815,221 to Diaz discloses a shoe sole having an energy control system located in a cavity of the sole, which comprises a set of spring strips and an overlying energy absorbing member capable of absorbing impact energy. In U.S. Pat. 4,774,774 to Allen, a shoe sole structure is disclosed comprising a plurality of vertically stacked disc-springs spanning the width and length of the sole to form a honeycomb framework which applies energy to the base of the foot upon release after load compression. A spring boot for bouncing and exercise is disclosed in U.S. Patent No. 4,660,299 to Omilusik, wherein a set of four coil springs is attached to the underside of a boot. U.S. Patent 4,506,460 to Rudy describes a spring-type moderator in combination with an air-cushioned sole in an athletic shoe providing improved shock absorption and energy return. A hopping and dancing shoe is described in U.S. Patent 4,457,084 to Horibata, et. al., comprising a shoe sole and two coil springs attached on its underside by bolts and nuts. In a similar design, U.S. Pat. 4,196,903 to Illustrato discloses a pair of jog-springs attached to the underside of a shoe sole providing a soft, bouncing action in use. In U.S. Pat. 3,777,374 to Hendricks, a pleasure shoe is disclosed having a compression spring unit fitted into a shoe heel for providing shock absorption. A shoe having a sole element provided with bores for retaining resilient means such as spring elements is disclosed in U.S. Patent 2,710,460 to Stasinos. In U.S. Patent 2,437,227 to Hall, a cushioned shoe sole is disclosed comprising a cushioning layer composed of resilient material with coil springs molded therein, and placed between top and bottom facing sheets. EP-A-0 215 491 discloses a cushioning assembly located in the rear part of the shoe, the assembly comprising a plurality of coil springs positioned between the outer sole and the shoe upper, the springs being adjustable and/or replaceable by access to the outer sole which come into contact with the ground. In EP-A-0 299 669 there is described a two-part shoe construction composed of a shoe body and a shoe sole according to the preamble of claim 1. Specifically, the two-part shoe construction provides a system for absorbing shocks and returning energy in the shoe sole, the system comprising a flexible sole cushion having formed on an upper side thereof, a plurality of recesses, and a layout of resilient members over the area of said flexible sole cushion, the layout providing shock absorption and energy return upon compression in accordance with a predetermined distribution pattern, the shoe body having a sealed bottom surface. As is well known, the feet, and particularly the soles of the feet, carry the entire body weight. The many shoe sole constructions found in the market absorb only a small portion of the shock caused as the shoe contacts the floor, and shocks which are not absorbed cause damage to the body. This occurs in the soles of the feet, which have many bones and many jointed surfaces, and in the knees which have fine meniscuses stabilizing the joints and permitting smooth movement. The spinal cord is built from many vertebrae, with discs between them which are very sensitive to changes, and which permit bending and straightening of the body. Over a long period of walking, the beating and shocks imparted to the soles of the feet may cause stress fractures in the legs. Also, these shocks cause changes in the structure of the vertebrae, affecting the discs between them by making them thin and irregular due to friction, so that they lose their flexibility. This damage causes limited movement and flexibility for the entire length of the spinal cord, leading to neck and shoulder pain, poor blood circulation, and stability problems. The effects of the damage to the discs are felt frequently in back pain, along with a tendency for increased fatigue, and over time the growth of bone fibers is expected in the area around the vertebrae. Sometimes this brings about a split in the disc as it explodes under pressure to its soft center. Damage to the discs of the vertebrae can also cause distortion in straightness of the back which brings about pressure on nerves and may cause a neurological block leading to paralysis. In addition, problems including headaches, dizziness and deadening of the senses cause major day-to-day discomforts. In order to solve these and other related problems, and to address the needs of individual users whose requirements vary, there is a need to provide an improved system of shock absorption which is user-specific and preserves the maximum amount of energy accumulating during compression of the material from which the sole is constructed, reducing wastage by friction or heat, enabling maximum energy to be returned after compression. Accordingly, it is a principal object of the present invention to overcome the above mentioned disadvantages of prior art shoe constructions and provide a user-specific coil spring system for a shoe sole featuring a customized layout covering various areas of the sole in accordance with user requirements. To achieve this, the two-part shoe construction of the invention is characterized by the features claimed in the characterizing part of claim 1. According to the invention, the layout comprises a plurality of coil springs, each of the coil springs being seated within one of the recesses, the predetermined distribution pattern being established in relation to a stiffness characteristic associated with each of the coil springs. The shoe sole comprises a cover strip overlaying the said flexible sole cushion and the coil springs to form a sealed unit. The sealed unit is removably insertable into a hollow base compartment in the shoe body via an opening in the shoe body, enabling replacement of the sealed unit with another and allowing variation of the coil spring layout and the predetermined distribution pattern. Advantageous embodiments of the invention are claimed in the subclaims. The method of assembling the two-part shoe construction of the invention is characterized by the features claimed in claim 13. In the preferred embodiment, the shoe sole coil spring system is a customized layout of individual coil springs which are seated in a shoe sole cushion having prefabricated circular depressions on its surface. The coil spring system layout and stiffness characteristics may be customized to serve the needs of different users and different applications. For example, depending on the weight of the user, a given shoe size may be fitted with a greater or lesser quantity of springs with different levels of stiffness, or the layout may be a combination of levels. The result is a shock absorption distribution pattern and energy return system for the shoe sole cushion to suit the requirements of the particular application. By virtue of its customized layout, the inventive shoe sole cushion design enables various problems to be addressed, including posture and balance, weakness and paralysis in the lower extremities, distortion in the vertebrae, hunchback, lordosis, fallen arches, etc. Stress fractures in the legs can be reduced. The customized layout may be implemented originally during shoe assembly, or it may be achieved by opening the shoe sole cushion and establishing a particular coil spring system layout at the point of sale. The second approach is made possible by a novel shoe sole cushion construction which permits opening and reclosing of the sole cushion for purposes of changing the spring system layout. Variations in the shoe sole cushion construction enable it to be used in several ways, such as by attachment under the shoe base, inserted via a slot formed in the base, or as a shoe pad. This permits the development of various customized spring layouts in accordance with a prescription from an orthopedic specialist. Using the prescription, a shoe salesman at a local store can implement the spring system layout, and if the user feels the need for adjustments, these can be made at the same time. Thus, maximum comfort is also achieved in the layout. Another feature of the invention is the provision of rounded tip or flat plugs for placement into the coil springs at their upper ends to give a textured or smooth finish to the shoe sole cushion. The rounded tip plugs are useful in enabling the practice of non-conventional medical technologies, such as reflexology, in specific cases, to stimulate the soles of the feet. Other features and advantages of the invention will become apparent from the drawings and the description contained hereinbelow. BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the invention with regard to the embodiments thereof, reference is made to the accompanying drawings, in which like numerals designate corresponding elements or sections throughout, and in which: Fig. 1 is a perspective view of a preferred embodiment of a shoe sole coil spring system layout constructed in accordance with the principles of the present invention; Fig. 2 shows a typical coil spring arrangement for use in the coil spring layout of Fig. 1; Fig. 3 is a perspective view of an alternative embodiment of the coil spring system layout of FIg. 1, featuring a reclosable sole cushion construction attachable to the shoe base; Fig. 4 is a perspective view of another alternative embodiment of the coil spring system layout, showing a reclosable sole cushion construction insertable via a slot in the shoe base; and Fig. 5 is a perspective view of still another embodiment of the coil spring system layout, showing a removable shoe pad insertable via the shoe opening. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to Fig. 1, there is shown a preferred embodiment of a shoe sole coil spring system 10 constructed in accordance with the principles of the present invention. Shoe 11 has a sole cushion 12 which is typically made of a flexible material, such as rubber, and is provided with a set of circular depressions or recesses 14 over its length and width. Each of recesses 14 may be filled with a suitably shaped filler material such as a rubber disc, which can be removed by prying loose from a given recess 14. In accordance with the invention, a set of coil springs 16 (Fig. 2) is provided for placement in recesses 14, and a customized layout of coil springs 16 may be developed by use of appropriate ones of recesses 14. A cover layer 17 is attached at the upper edges of sole cushion 12 to enclose the coil spring system 10. In use, as body weight is applied via the foot to sole cushion 12, the user benefits from a shock absorption distribution pattern and energy return system provided in accordance with the customized coil spring system 10 layout. For example, based on the fact that the entire body weight is supported by the rear portion of foot, that is, the calcaneus, coil spring system 10 may use springs having a higher stiffness in this area, i.e. a greater spring constant, to aid a user in maintaining proper posture. This may be accomplished by providing the springs in this area with approximately 25% greater stiffness than those in the remaining areas of sole cushion 12. In Fig. 2, a typical coil spring arrangement is shown, in which a plug 18, typically made of plastic, is provided for seating within coil spring 16 itself at either end. The lengths of plugs 18 are designed such that their opposite ends do not contact one another when spring 16 is compressed. Plug 18 has a flat head, while another type plug 19 has a rounded tip. Each of plugs 18, 19 is shaped with a shoulder against which an end of spring 16 rests. As described further herein, while the flat head of plug 18 is normally used in system 10, rounded tip plug 19 may be used for specific requirements relating to foot stimulation. The inventive coil spring system 10 layout may be adapted for many applications, including walking, dancing, running or jumping in sports applications, for use in hiking shoes, in weight-bearing work shoes, or for use in a reflexology technique to apply pressure points for foot stimulation in specific areas. Each of these applications requires a particular solution since each creates different pressures on different areas of the foot, or no pressure at all. These differences must be expressed in relation to the body weight, that is, in order to provide a comfortable solution to different users, even though they may have the same size foot. Thus, for a body weight of between 60-80 kg., the springs 16 used may have a spring constant K, and for body weight of 80-100 kg, a spring constant K1 may be used, while for a body weight of 100-120 kg, a spring constant K2 may be used, wherein the spring constants follow the relation: K < K1 < K2. As stated above, different applications require different solutions which minimize the damaging effects of shocks to the feet. For example, while dancing, the feet experience shocks which are greater than those produced by walking, and much pressure is exerted on the toes. Thus, the stiffness of the springs placed in these areas should be higher, in order to minimize shocks to the body. In another application such as sports, where jumping and running are the main activities, especially high shocks are imparted to the feet. In order to minimize these shocks, and to utilize the energy absorbed by the coil spring system 10 with maximum efficiency, the spring constant of coil springs 16 in the area of the calcaneus and the metatarsus must be increased accordingly. The energy return function of springs 16 literally "pushes" the foot upwards after compression. Referring now to Fig. 3, there is shown a perspective view of an alternative embodiment of the coil spring system 10 layout of Fig. 1, featuring a reclosable sole construction enabling layout changes. In this embodiment, shoe sole cushion 12 is provided with a contoured rib 20 integrally formed therewith and extending around its circumference, which is fabricated of the same flexible material as sole cushion 12. Cover layer 17 is provided as the bottom surface of the upper portion of shoe 11, and has formed about its circumference a groove 22 shaped so as to engage contoured rib 20 when pressed therein, enabling coil spring system 10 to be closed by attaching cover layer 17 to sole cushion 12. By prying contoured rib 20 out of groove 22, shoe sole cushion 12 may be opened, so that the customized layout of coil spring system 10 may be changed. As a result of this novel construction technique, the shock distribution pattern and energy return system provided by shoe sole cushion 12 may be adjusted at the point of sale to suit the above-described user applications. That is, by opening of shoe sole cushion 12 and addition or removal of coil springs 16 or variation in their layout, the requirements of different applications can be addressed. Reclosing sole cushion 12 is easily achieved by pressing contoured rib 20 into groove 22 of shoe 11. In Fig. 4. another alternative embodiment of the coil spring system 10 layout of Figs. 1 and 3 is shown in perspective, featuring a reclosable sole cushion construction which is removable from shoe 11 for making layout changes. In this arrangement, sole cushion 12 is fitted within a hollow base compartment 24 of shoe 11, via a slotted opening 26 in shoe wall 27. A pair of contoured ribs 20 and grooves 22 are provided respectively on the outer edge 28 of sole cushion 12, and on the upper and lower edges of slotted opening 26. Once cover layer 17 is placed over sole cushion 12 and it is fitted within base compartment 24, ribs 20 and grooves 22 can be used to lock sole cushion 12 in position. A particular advantage of this embodiment is the possibility of having a plurality of pre-designed customized layouts of coil spring system 10 in individual sole cushions 12, each available for immediate use in a particular group of applications. Thus, a user could purchase a shoe and specify a particular application, i.e., walking, sports, or dancing, which is then matched with a pre-designed customized layout. The appropriate shoe sole cushion 12 is then selected and inserted into base compartment 24 of shoe 11, wherein it is locked in position. If adjustments are needed, the shoe sole cushion 12 can be removed through slotted opening 26, and cover layer 17 may be opened for making changes in the layout. Another possible approach is the provision of a prescription from an orthopedist or podiatrist which specifies the areas of the sole cushion 12 which are to be treated by the beneficial effects of the customized layout, including the necessary spring characteristics, etc. The user could present the prescription to the vendor of the inventive shoe sole cushion 12 design, who could then implement the appropriate customized layout. In Fig. 5. still another alternative embodiment is shown, in which sole cushion 12 is arranged as a shoe pad design, which can be removably inserted in shoe 11. In this arrangement, shoe 11 is manufactured with a sealed bottom surface such as rubber, but without a sole cushion 12, and hollow base compartment 24 is adapted to allow push-fit insertion of sole cushion 12 therein. Shoe 11 then completely encloses sole cushion 12 without need for further closure means, and shoe walls 27 maintain it fixed in position. A contoured pull strap (not shown) may be attached at the end of sole cushion 12, and tucked against the shoe heel wall, for easy removal. A particular advantage of this approach is that as the shoe pad design of sole cushion 12 is worn, it adjusts itself to the contour of the foot, becoming more comfortable. This comfort may be transferred by removing sole cushion 12 from one shoe 11 and inserting it in a new shoe body which replaces a worn-out one. This achieves a cost savings as well, since only a new shoe body must be purchased, and a used sole cushion 12 can be inserted therein. Alternatively, a user may choose to purchase several different sole cushions 12 for each of shoes 11, so that different customized layouts of coil spring system 10 may be applied in accordance with different intended applications, as described. In summary, by virtue of its customized layout, the inventive coil spring system and shoe sole cushion design minimizes various shock absorption problems of the feet and legs, including those leading to stress fractures and other damage related to specific user applications.

Claims: A two-part shoe construction composed of a shoe body (11) and a shoe sole, said two-part shoe construction providing a system (10) for absorbing shocks and returning energy in the shoe sole, said system comprising: a flexible sole cushion (12) having formed on an upper side thereof, a plurality of recesses (14), a layout of resilient members (16) over the area of said flexible sole cushion (12), said layout providing shock absorption and energy return upon compression in accordance with a predetermined distribution pattern, the shoe body (11) having a sealed bottom surface, characterized in that said layout comprises a plurality of coil springs (16), each of said coil springs (16) being seated within one of said recesses (14), said predetermined distribution pattern being established in relation to a stiffness characteristic associated with each of said coil springs (16), and in that said shoe sole comprises a cover strip (17) overlaying said flexible sole cushion (12) and said coil springs (16) to form a sealed unit (12, 17), said sealed unit (12, 17) being removably insertable into a hollow base compartment (24) in the shoe body (11) via an opening in the shoe body (11), enabling replacement of said sealed unit (12, 17) with another and allowing variation of said coil spring layout and said predetermined distribution pattern. The construction of claim 1, characterized in that said plurality of coil springs (16) have varying stiffness characteristics each in relation to its associated spring constant. The construction of claim 1, characterized in that said cover strip (17) is attached to said flexible sole cushion (12) in separable fashion so as to allow access to said coil spring layout for making changes therein in accordance with user-specific requirements. The construction of claim 3, characterized in that said cover strip (17) is provided with a rib (20) extending around its circumference and said flexible sole cushion (12) is provided with a groove (22) formed in its outer circumference, said rib (20) being removably insertable into said groove (22) for attaching said cover strip (17) to said flexible sole cushion (12). The construction of claim 1, characterized in that said sealed unit (12, 17) is removably insertable into said hollow base compartment (24) via a slotted opening (26) in said shoe body (11). The construction of claim 5, characterized in that said sealed unit (12, 17) has formed on an outer edge (28) thereof a set of grooves (22) into which ribs (20) provided on said slotted opening (26) are insertable, for locking said sealed unit (12, 17) into position. The construction of claim 1, characterized in that each of said coil springs (16) has mounted therein at an end thereof a substantially cylindrical plug (18) formed with a shoulder upon which said coil spring end rests. The construction of claim 7, characterized in that said plug (18) has a flat head. The construction of claim 7, characterized in that said plug (18) has a rounded tip (19) for providing stimulation of a particular area of the foot. The construction of claim 1, characterized in that said cover strip (17) is provided with a circumferential rib (20) extending around its circumference which is removably insertable into a groove (22) formed in the circumference of said flexible sole cushion (12) for attaching said cover strip (17) to said flexible sole cushion (12), thereby allowing access to said coil spring layout for making changes therein in accordance with user-specific requirements. The construction of claim 10, characterized in that said sealed unit (12, 17) is removably insertable into said hollow base compartment (24) via a slotted opening (26) in said shoe body (11). The construction of claim 10, characterized in that said sealed unit (12, 17) is removably insertable into said hollow base compartment (24) via the top opening of said shoe body (11). A method of assembling the two-part shoe construction of claim 1 to enable customizing the coil spring system layout designed to absorb shocks and return energy in the shoe sole in accordance with user-specific requirements, characterized in that said method comprises the steps of: removing the shoe sole cushion (12) from the hollow base compartment (24) of the shoe body (11), separating from the shoe sole cushion (12) the cover layer (17) overlaying and enclosing the coil spring system in the shoe sole cushion (12), adjusting at least one of the layout and stiffness of coil springs (16) in the opened shoe sole cushion (12) so as to customize it, replacing said cover layer (17) on said customized shoe sole cushion (12), and replacing said customized shoe sole cushion (12) in said shoe body (11). The method of claim 13, characterized in that said shoe sole cushion removal and replacement steps are performed by opening a slot (26) formed in said base compartment (24) of said shoe body (11), and sliding said shoe cushion (12) therethrough. The method of claim 13, characterized in that said shoe sole cushion removal and replacement steps are performed by respectively pulling and pushing said shoe sole cushion (12) through the top opening in said shoe body (11). The method of claim 13, characterized in that said cover layer separating step is performed by prying a rib (20) formed on the circumferential edge (28) of said shoe sole cushion (12) from a groove (22) formed in the circumference of said cover layer (17). The method of claim 13, characterized in that said cover layer replacing step is performed by pressing a rib (20) formed on the circumferential edge (28) of said shoe sole cushion (12) into a groove (22) formed in the circumference of said cover layer (17).

Inventors: RONEN SAMUEL, TALMOR SHOSHANA, RONEN, SAMUEL, TALMOR, SHOSHANA
Applicants: RONEN SAMUEL, TALMOR SHOSHANA, RONEN, SAMUEL, TALMOR, SHOSHANA
Application year: 1991
Main classification: A43B13
IPC codes: A43B13