Patent Publication Number: US-5832629-A

Title: Shock-absorbing device for footwear

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to a footwear cushion, and more particularly to a footwear shock-absorbing device. 
     BACKGROUND OF THE INVENTION 
     The U.S. Pat. Nos. 2,668,374; 4,267,648; and 4,322,893 disclose respectively a shoe sole which is provided with a plurality of coil springs for absorbing impact. The coil springs are used to mitigate the shock in view of the fact that they can be easily made at a low cost, and that the coil springs of various specifications are always available. Nevertheless, a variety of problems often arise from the coil springs, which can not be easily located and must be provided with the rigid plates that are fastened with the free ends of the coil springs so as to prevent the stress from being concentrated on the free ends of the coil spring. Such a footwear shock-absorbing device as described above is limited in design in that it is not cost-effective, and that it can not be used in all kinds of footwear, and further that it makes a footwear uncomfortable to wear. 
     The U.S. Pat. No. 5,343,637 discloses a footwear shock-absorbing device capable of overcoming the drawbacks of the coil springs described above. However, this disclosure is rather complicated in construction and is therefore not cost-effective. 
     SUMMARY OF THE INVENTION 
     It is therefore the primary objective of the present invention to provide a footwear shock-absorbing device suitable for use in a variety of shoes which are available in the market place today. 
     It is another objective of the present invention to provide a footwear shock-absorbing device which makes use of the coil springs and is relatively simple in construction and cost-effective. 
     It is still another objective of the present invention to provide a footwear shock-absorbing device with a flat and smooth receiving surface for preventing the stress from being concentrated on the free ends of the coil springs. 
     In keeping with the principle of the present invention, the foregoing objectives of the present invention are attained by a footwear shock-absorbing device, which comprises a lower receiving member having a flat bottom mountable in the receiving cell of a footwear sole. The flat bottom is provided with a plurality of columnar projections. The device further comprises an upper receiving member having a flat top in contact with the pad of the footwear. A plurality of fastening members are disposed between the lower receiving member and the upper receiving member such that the fastening members are fastened respectively at one end thereof with the flat top of the upper receiving member, and at another end thereof with the columnar projection, and that the fastening members are respectively fitted into a coil spring. The coil spring has two ends urging respectively the flat bottom of the lower receiving member and the flat top of the upper receiving member so as to keep each of the fastening members to locate at an upper dead point at such time when the fastening members are not exerted on by an external force. 
     The foregoing objectives, structures, features, functions, and advantages of the present invention will be more readily understood upon a thoughtful deliberation of the following detailed description of the embodiments of the present invention in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a side elevational view of a first preferred embodiment of the present invention. 
     FIG. 2 shows a top plan view of the first preferred embodiment of the present invention. 
     FIG. 3 shows a sectional view of a portion taken along the direction as indicated by a line 3--3 shown in FIG. 2. 
     FIG. 4 shows a bottom plan view of the first preferred embodiment of the present invention. 
     FIG. 5 is a schematic view illustrating the structure of a footwear shock-absorbing device in combination according to the first preferred embodiment of the present invention. 
     FIG. 6 shows a sectional view of a second preferred embodiment of the present invention. 
     FIG. 7 shows a sectional view of a third preferred embodiment of the present invention. 
     FIG. 8 shows a sectional view of a fourth preferred embodiment of the present invention. 
     FIG. 9 shows a side elevational view of a fifth preferred embodiment of the present invention. 
     FIG. 10 shows a side elevational view of a sixth preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in FIGS. 1-4, a footwear shock-absorbing device embodied in the present invention is composed of a lower receiving member 10, an upper receiving member 20, a plurality of fastening members 30, and a plurality of coil springs 40. 
     The lower receiving member 10 has a flat bottom 12 capable of being located in an inner bottom 02 of the receiving cell of a footwear sole 00. The flat bottom 12 is provided with a plurality of columnar projections 14 extending upwards. Each of the columnar projections 14 has a large hole 141 extending from the bottom thereof towards the top thereof, and a small hole 143 extending from the top thereof towards the bottom thereof. Located at the junction of the large hole 141 and the small hole 143 is a flat circular face 145. 
     The upper receiving member 20 is located on the lower receiving member 10 and is provided with a flat top 22 on which a shoe pad 04 is mounted. The upper receiving member 20 is provided with a plurality of through holes 24 corresponding in number and location to the columnar projections 14. 
     The fastening members 30 are provided respectively with two stopping blocks 32 and 34, which are made integrally of a plastic material by injection molding and are inserted into the through holes 24 and the corresponding columnar projections 14 for enabling the stopping blocks 32 and 34 to be retained by the through hole 24 of the upper receiving member 20 and on the circular faces 145 of the columnar projections 10. The stopping block 34 is provided with two slots 341 and 343, which are normal to each other and arranged in a cruoiform shape. 
     The coil springs 40 have a free length equal to or longer than the length of the fastening members 30 and are fitted respectively over the fastening members 30 such that both ends thereof urge respectively the inner faces 16 and 26 of the two receiving members 10 and 20. 
     As shown in FIGS. 3 and 5, the stopping block 34 located at the tail end of each of the fastening members 30 is tapered along its outer circumferential edge and is provided with the slots 341 and 343 such that the stopping block 34 of the plastic material is resilient radially, and that the stopping block 34 is capable of recovering its original shape after being forced into the through hole 24 and the corresponding columnar projection 14. The stopping block 34 is forced by the spring 40 to engage securely the flat circular face 145, thereby enabling the upper receiving member 20 and the lower receiving member 10 to join together securely as a shock-absorbing unit. The shock-absorbing unit is embedded in the footwear sole such that the spring compression stroke h is capable of mitigating the impact on a foot wearing the footwear. The compression stroke h referred to above is smaller than or equal to the depth H of the large hole 141 of the columnar projections 14. Further the fastening members 30 can be provided with two fastening bolts 36 and 38 for holding the component members together, as shown in FIG. 6. 
     As illustrated in FIG. 7, the upper receiving member 20 and the fastening members 30 are made integrally, as designated by 90. It is also suggested that the through hole 24 of each of the upper receiving members 20 is provided with a pillow hole 28 for averting the concentration of stress on the stopping block 32 located at the top end of each of the fastening members 30, as shown in FIG. 8. 
     As shown in FIG. 9, the present invention may be embodied in such a manner that the lower receiving member 50 is provided with a plurality of columnar projections 52, and that the fastening member 30 is put through the columnar projections 52 so as to enable the stopping block 34 to engage the lower receiving member 50. Space 05 is provided below receiving member 50 to furnish room for stopping block 34 when a user compression springs 40 when walking 
     As shown in FIG. 10, a shoe midsole 08 of a soft and elastic material is provided with a rigid base 60 for supporting the shock-absorbing device of the present invention, which is located in a receiving cell 62 of the base 60. In addition, the upper receiving member 20 of the present invention may be provided with a plurality of columnar projections extending downwards for locating the coil springs. The embodiments of the present invention described above are to be regarded in all respects as being merely illustrative and not restrictive. The present invention is therefore to be limited only by the scopes of the following appended claims.