WO1997015206A1

WO1997015206A1 - Impact-cushioning device for sports footwear

Info

Publication number: WO1997015206A1
Application number: PCT/NO1996/000249
Authority: WO
Inventors: Karl-Willie Hoel
Original assignee: Hoel Karl Willie
Priority date: 1995-10-25
Filing date: 1996-10-23
Publication date: 1997-05-01
Also published as: NO954264D0; AU7345596A

Abstract

A sports footwear device, wherein a plurality of stud-shaped members (1; 18) preferably in the approximate form of an inverted, truncated cone, are incorporated into the wearing surface of the sole. Each member has a cavity (4; 21, 22) situated axially opposite to the wearing surface (3'; 18') of the member, designed to absorb volume changes in said member on application of impact/pressure loading thereagainst. Said members may either constitute an integrally moulded part of the footwear outsole (19), or be designed with a screw head (2') for insertion in the footwear sole.

Description

IMPACT-CUSHIONING DEVICE FOR SPORTS FOOTWEAR

The present invention relates to a shock-absorbing device for sports footwear, wherein a plurality of stud-shaped members, preferably in the approximate form of an inverted, truncated cone, are incoφorated into the wearing surface ofthe footwear sole, and wherein said members are formed of a uniformly moulded part ofthe footwear outsole, a means for inserting a shock-absorbing stud into a footwear sole, and a shock- absorbing stud for a sports footwear sole, preferably in the approximate form of an inverted, truncated cone, provided with a head for insertion into the sole ofthe footwear, e.g., by screwing, a retaining piece and a gripping piece surrounding the retaining piece, said gripping piece having a preferably beveled section intended to rest against the footwear sole.

It is known in connection with sports footwear to use interchangeable studs that are fixed with threads to a screw insert securely connected to the sole ofthe shoe. The screw insert may be moulded in place, pressed into the outsole or pressed through both the lining, or intermediate sole, and the outsole. Such screw inserts consist of a cylindrical internally threaded part and a flange having vertical lugs. The flange holds the screw insert in place axially and the vertical lugs prevent rotation. The usual thread size is M5, but other dimensions are also used. There are also solutions where the stud's retaining piece is attached directly to the outsole via a threaded portion moulded as a part ofthe outsole. The gripping members for the known studs are usually produced from plastics or metal. There are also gripping members of rubber or plastic for hard fields which have a relatively large diameter and have a material hardness that has minimal shock-absorbind effect. The screw inserts used today are permanently mounted in the shoe sole. The forces applied to the studs' gripping members on impact are conducted directly further due to the rigid connection. Because of this rigid connection between the gripping member and the screw insert, severe pressures at concentrated points are imposed on impact, causing discomfort for the footwear user.

In the known solutions where the studs are an integral part ofthe outsole, it is a known problem that the studs provide little or no impact cushioning due to their massive structure and high degree of material hardness. It is also known that integrated soles are produced with a small depression at each stud in order to reduce material consumption, decrease the weight ofthe sole and, for reasons pertaining to moulding technique, reduce material tensions as the material solidifies. Such solutions are known in particular from footwear for ball games, e.g., football or soccer. These solutions are especially disadvantageous for use on a hard surface.

Also previously known are complicated stud constructions which have proven to be poorly suited for mass production. Such studs also have had minimal cushioning capability, hold little possibility for volume change, and have been based on the special adaptation to a specific type of sole.

The present invention therefore aims to provide solutions that remedy the disadvantages ofthe hitherto known structures.

Said stud as introduced hereinabove, said means, and said device are characterized by the features disclosed in the respective patent claims attached hereto.

Additional features and advantages of the invention will be apparent from the following description, with reference to the attached drawings, while the embodiments that are shown serve merely to elucidate the inventive concept and may be regarded as embodiment examples.

Figure 1 is a cross-sectional view of a shock-absorbing stud, according to the invention.

Figure 2 is a plan view ofthe stud in Figure 1, seen from above.

Figures 3, 4 and 5 are modifications ofthe embodiment form in Figure 1.

Figure 6 is an illustration of a further modification of a shock-absorbing stud, and Figure 7 is a top view ofthe stud in Figure 6.

Figure 8 illustrates a modification ofthe stud in Figure 6.

Figure 9 is a cross-sectional view of still another modification of a shock-absorbing stud, according to the invention.

Figure 10 shows a variant ofthe embodiment in Figure 9.

Figure 1 1 shows a variant of the embodiment in Figure 1. Figure 12 shows a modification ofthe embodiment in Figure 10.

Figures 13 and 14 show variants ofthe embodiment in Figure 1 1.

Figure 15 shows a modification ofthe embodiment in Figure 12.

Figure 16 shows still another modification ofthe embodiment in Figure 12.

Figure 17 is a sectional view of a retaining piece indicated in Figure 18, taken along line XVII-XVII.

Figure 19 shows a modified retaining piece.

Figure 20 is a plan view ofthe embodiment in Figure 19, taken from the top, and Figure 21 is a side view ofthe embodiment in Figure 19.

Figure 22 is a view of a retaining piece as is typically used in connection with the embodiments in Figures 13, 14 and 15.

Figure 23 is a plan view ofthe embodiment in Figure 22, seen from above.

Figure 24 shows a possible insertion/attachment means for a shock-absorbing stud.

Figure 25 illustrates the typical insertion/attachment ofthe shock-absorbing stud, viewed from above, as indicated in Figure 24.

Figure 26 is a view of an alternative form of a sports footwear device wherein a plurality of uniformly shaped, stud-like members are incoφorated into the outsole ofthe footwear.

In Figures 1, 3-6 and 8 a device is shown, in cross section, wherein said member is designated by reference number 1 and consists of a retaining piece 2 having a helical head section 2' for insertion and attachment into the footwear sole. Although a screw attachment is shown and prescribed here, it is also conceivable to use a bayonet fitting or a releasable snap attachment. Member 1 also has a gripping piece 3 surrounding retaining piece 2, in such manner that they together form a cavity 4. Gripping piece 3 has, in addition, a section 3' which forms the wearing surface of member 1.

The embodiment form in Figures 1, 3-6 and 8 and 9 preferably has a cross section approximately like that of an inverted, truncated cone. As is shown for the embodiment form in Figures 1 -5 and 9, retaining piece 2 is formed with a cup-shaped recess 2" or, as shown in Figure 6, with a depression 2'". As is common to the embodiments in Figures 1 and 3-5, head section 2' is integrated with the bottom 2"" ofthe cup-shaped portion. Alternatively, as shown in Figure 6. the helical head section may be disposed on the opposite side of depression 2"'.

As shown in Figure 1 , cavity 4 may be nearly annular in form. Alternatively, as shown in Figures 3 and 5, the cavity may have the approximate form of an inverted bowl. In Figure 4 it is shown that the cavity may have an almost cylindrical form. According to the solution in Figure 6, it is possible for cavity 4 to have a nearly hemispherical or domed shape, seen in cross section. It is apparent from the embodiment forms in Figures 1, 3, 4 and 5 that gripping piece 3 partially fills recess 2" in the cup-shaped portion and together therewith forms said cavity 4. In the embodiment in Figure 6 it is the actual depression 2"' together with the flat surface 3' of gripping piece 3 which forms cavity 4.

In the embodiment in Figure 8 it has been chosen to give retaining piece 2 a flat bottom 5 which, together with a cutaway sector 6 in gripping piece 3, forms cavity 4. The cavities 4 as shown in the embodiment form in Figures 1-8 may be filled with air or with a compressible material, for example, rubber or various types of TPE. Figure 9 shows such a solution wherein the entire cup-shaped portion 2" of retaining piece 2 is filled with such a compressible material, such that gripping piece 3 in a uniform way thereby also fills in portion 2".

In any case, it is important that gripping piece 3 be resilient and has a low E-module in order to provide the desired absorbing effect. Further, it is important that retaining piece 2 has a high E-module so that the full member 1 is also provided with a good lateral stability.

Gripping piece 3 may advantageously be made of a material demonstrating high wear resistance and surface friction, for example, rubber. Howerer, the choice of other synthetic materials having comparable properties, e.g., thermoplastic polyurethane, is not excluded.

Experience has shown that gripping piece 3 and retaining piece 2 may advantageously be fastened together by gluing, vulcanization or use of a primer which ensures coherence. Coherence between gripping piece 3 and retaining piece 2 without use of glue, primer or vulcanization is also possible.

As is apparent from, for example, Figure 3, it is possible to provide a stepped-down edge portion 7 on retaining piece 2 and a correspondingly shaped catching edge portion 8 on gripping piece 3. This ensures stronger mechanical attachment when gripping piece 3 is snapped onto retaining piece 2.

It will be advantageous to design gripping piece 3 with an upwardly inclined outer edge 3" so that when gripping piece 3 is screwed into the footwear sole, the material therein is tensioned against the sole, thereby preventing penetration of water and particles between stud-shaped member 1 and the footwear outsole. The upwardly inclined edge 3" will also assist in preventing rotation of member 1 relative to the footwear outsole during application of pressure/impact, in addition to contributing toward increased energy absoφtion through change of shape.

A depressed, annular section or groove 9 is provided around head 2' on the retaining piece. The function ofthe groove is to allow space for a raised or skewly mounted insert (not shown) in the footwear sole. This insert normally should not project beyond the surface ofthe sole, but in practice this could happen. Without this groove in the retaining piece, the stud would abut with the slightly projecting threaded insert rather than with the sole. This could result in a slight gap of a few tenths of a millimeter. Such a gap could be sufficient to subject the head to a bending moment and, finally, to possible fatigue breakage. The distribution of forces is also reduced when retaining piece 2 bears against the insert instead of against the footwear sole.

Figures 10 and 11 are included merely to show that retaining piece 2 may have various widths with regard to the cup-shaped portion 2". In the embodiments in Figures 12, 13, 14 and 15, it will be seen that retaining piece 2 at the transition to head section 2' has a projecting contact shoulder 12, and that a portion 3'" of gripping piece 3 overlies this shoulder 12. This enhances engagement between the gripping piece and the retaining piece, not least in the axial direction of said gripping- and retaining pieces. In Figure 16 a variant ofthe projecting contact shoulder 12 is shown, namely a beveled contact surface 12'. This contact surface 12' may continue completely around head section 2, or the beveled sectors may be like those indicated by reference number 10 in Figures 17 and 18, viz. formed by cutaway sectors made in retaining piece 2.

Alternative cutaways sectors, such as those shown in Figures 19-21 and indicated by reference numeral 11, will be possible. These solutions will also have the effect of enhancing the axial adherence between retaining piece 2 and gripping piece 3. The section through line XIX-XIX is shown in Figure 19.

Figures 22 and 23 show a typical retaining piece 2 which does not have the cutaway sectors 10 or 11 and which is depicted as used in connection with the embodiments in Figures 13, 14 and 15, in particular.

The insertion, or attachment, into the footwear outsole may be done in several ways, e.g, by screwing, snapping, using a bayonet fitting, or a similar means. However, a currently favored embodiment is shown in Figures 24 and 25. The intermediate sole, or lining, ofthe footwear is designated by reference numeral 13, and the outsole ofthe footwear by reference numeral 14. Even though a specific type of shock-absorbing stud is shown, it will be understood that any one ofthe shock-absorbing studs shown in Figures 12-16 could be used, as well as optional modifications and variants thereof. When using a standard, permanent screw insert in the outsole, any one ofthe embodiments in Figures 1-16 could be employed.

Outsole 14 has a hole of a given diameter which passes into a cavity 15 having a larger diameter and, preferably, an oval shape. A loose insert 16 is designed to be mountable in the hole 14' before intermediate sole 13 is attached to outsole 14, e.g, by gluing. Insert 16 is, in other words, not moulded into outsole 14, but is axially movable relative thereto. It is provided with flange portions 16' which rest against the edge 15' of cavity 15, preventing the insert from sliding out of outsole 14. However, insert 16 will be axially movable relative to outsole 14 over a small axial portion of cavity 15. Preferably the flange-shaped portion 16' of insert 16 — similarly to a cross section of cavity 15 — will have an oval or non-circular form in order to counteract torsional moment when the shock-absorging stud is screwed in or attached. The internally threaded portion of insert 16 may also have an external configuration designed for maximum resistance to potential twisting moments and to the tendency to loosen. At the exterior of outsole 14 as an extension of insert 16 there optionally may be provided a fixed ring 17. This ring or washer 17 will ensure secure attachment ofthe shock-absorbing stud to insert 16.

When the shock-absorbing stud is subjected to axial pressure, the edge portion 3" will be compressed at the same time as retaining piece 2 secured to insert 16 will move slightly inwards, as far as the axial extent of cavity 15 permits.

With the embodiment shown in Figures 24 and 25 there is achieved a transfer and distribution ofthe forces of impact over outsole 14, instead of a spot-loading closely associated with the point of attachment ofthe shock-absorbing stud.

On attachment/insertion of gripping members made of a hard material which is ineffective as a shock-absorber, the screw insert 16 will function as a loose nut which becomes tensioned against an inside shoulder in the shoe outsole.

By designing the retaining pieces as shown in Figures 17, 18 and 19-21, for example, one attains improved attachment ofthe gripping piece and better lateral stability, at the same time as the adherence between the retaining piece and gripping piece will be enhanced. The internal cavity 2" will, as mentioned previously, ensure the mechanical blockage of horizontal forces and reduction of shear stresses at the interface between the retaining piece and the gripping piece, as well as maintaining a variable absorbing characteristic together with the gripping piece. Further, the cavity reduces the weight ofthe retaining piece. The grooves or cutaway sectors 10, 11 will, in addition to the effects mentioned earlier, contribute toward mechanical obstruction of tangential forces and reduction of shear stresses at the interface between the retaining piece and the gripping piece, and will provide channels filled with resilient material which further strengthen the adherence upon shrinkage. In addition, cutaway sectors or grooves 10 or 1 1 contribute toward reduction ofthe weight ofthe retaining piece.

As shown in the embodiment forms in Figures 1-16 and 24, the gripping piece is shaped approximately like an inverted, straight truncated cone. The gripping piece is preferably made of a resilient material, such as rubber or various types of thermoplastic elastomer (TPE). As shown on the drawings, the gripping piece essentially surrounds the retaining piece both inside and outside. The shock-absorbing properties of gripping piece 3 may be varied by changing its material hardness and by altering its internal profile, as is clearly indicated on Figures 1-16 and in Figure 24. The shock-absorbing properties of gripping piece 3 in the embodiments shown in Figures 12-16 are based on a two-stage effect. In the first stage, the lower part ofthe gripping member is deformed, partly by an exterior change in the shape ofthe resilient material extending outward beyond retaining piece 2, and partly by an internal change in the shape ofthe resilient material in cavity 2" of retaining piece 2. Impact cushioning occurs by the absoφtion ofthe energy of impact over time, whereby the retardation per time unit decreases. Then, the material at the interface between the outsole and the retaining piece is pressed together, and further shock-absorbing will be attained. This pertains particularly to the embodiments shown in Figures 12-16, and 24.

The solution shown in Figure 24 affords the advantage that insert 16 may optionally be replaced, in a basically simple manner, if there should occur any damage to the threads or if the threaded neck 2' of retaining piece 2 should break and become wedged inside insert 16. The replacement could be accomplished in a simple manner by lifting up the intermediate sole or the insole 13, whereupon screw insert 16 will fall out when the shoe is held upside down. A new screw insert may then be inserted in a simple fashion without any form of special tools. To summarize, the insertion/attachment solution shown in Figure 24 will result in gradual absorbing whereby, in the first stage, the lower part ofthe gripping member undergoes a change of shape on impact, enabling the energy to be absorbed over time. Then, on extreme impact or pressure, the forces imposed on the gripping member will alter the form ofthe resilient material located at the interface region between the outsole and the retaining piece. In Figures 1, 3, 4-6, and 8-11 this is indicated by reference number 3", whereas in Figures 12-16 and 24 it is indicated by reference number 3'". Here the shock-absorbing also occurs over time.

On medium to heavy impacts, screw insert 16 will move upwards, but due to its potential for free axial movement, the screw insert will be unable to transfer vertical forces to the outsole ofthe footwear. However, when screw insert 16 moves axially some tenths of a millimeter or more, vertical forces will be transferred from gripping piece 3 to footwear sole 14, where they are distributed over a large area due to the compression ofthe elastic material in gripping piece 3 between retaining piece 2 and the exterior surface of outsole 14. Concentrated impact loading via the threaded connection is thereby eliminated.

Figure 26 shows an embodiment ofthe device, according to the invention, where stud- shaped members 18 are an integral part ofthe footwear outsole 19. The stud-shaped members 18 have approximately the shape of an inverted, truncated cone. The intermediate sole, or lining, ofthe footwear is indicated by reference numeral 20. Said members 18 each have two cavities 21, 22 which are situated axially opposite to the wearing surface 18' of member 18. Cavity 22, extending laterally outward beyond the vertical extension ofthe exterior profile ofthe gripping member, contributes together with the exterior configuration to the shock-absorbing property. The puφose of cavity 21 is primarily the desire within foundry technology to reduce material tensions on skrinkage, as well as to reduce weight.

Reference numerals 21, 22 designate the common cavity between shock-absorbing stud 18 and intermediate sole 20. The shock-absorbing stud 18 is formed integrally with outsole 19 and has an outwardly oriented elastic, resilient transitional section 23 which imparts increased property of elasticity to the shock-absorbing stud 18. On impact loading there will occur a bending of sector 18 in the direction of intermediate sole 20, whereby cavity 22 decreases in size. Cavity 21, 22 and the external profile of transitional section 23 must be designed with an eye toward minimizing material tensions and thereby preventing material fracture or permanent deformation.

From the preceding description it will be understood that the elasticity characteristic for both interchangeable studs (Figures 1-25) and integrated studs (Figure 26) may be varied. Integrated studs may be modified by varying the geometry ofthe cavity or the external shape ofthe stud. Replaceable studs may be varied by modifying the configuration of retaining piece 2 and gripping piece 3, the size and shape of cavity 4, and the form of contact area 3" or 3"', at the same time as the elasticity characteristic may be varied by altering the hardness ofthe material.

Claims

P a t e n t C l a i m s

1.

An shock-absorbing stub (1) for a sports footwear sole, preferably in the approximate form of an inverted, truncated cone, provided with a head (2') for insertion into the footwear sole, e.g., by screwing, a retaining piece (2) and a gripping piece (3) surrounding the retaining piece (2), said gripping piece having a portion (3") which is beveled to rest against the footwear sole, characterized in that the retaining piece (2) and the gripping piece (3) together form a cavity (4), which is situated axially opposite to the wearing surface (3¹) ofthe stud, with its opening oriented in the direction of the wearing surface in order to absorb volume changes in the stud on application of impact/pressure loading against the wearing surface, that the cavity (4) is situated inside the circumference ofthe retaining piece (2), that the cavity is filled with air or with a compressible material, e.g., rubber or TPE, and that the gripping piece is resilient and has a low E-module in order to provide for an absorbing function, and that the retaining piece has a high E-module in order to provide said stud (1) with lateral stability.

2.

A shock-absorbing stud as disclosed in claim 1, characterized in that the retaining piece (23) is formed with a cup-shaped portion having a recess (2"), or is provided with a depression (2'"), in order to form, at least in part, said cavity (8).

3.

A shock-absorbing stud as disclosed in claim lor2, characterized in that the gripping piece (3) partially fills the recess or depression in the retaining piece (2) in order together with the retaining piece to form said cavity (4).

4.

A shock-absorbing stud as disclosed in one or more ofthe preceding claims, characterized in that the cavity (4) has approximately a hemispherical, annular, cylindrical or bowl-shaped form.

5.

A shock-absorbing stud as disclosed in one or more ofthe preceding claims, characterized in that the retaining piece is designed with cutaway sectors (10; 11 ) on its perimeter.

6.

A shock-absorbing stud as disclosed in one or more ofthe preceding claims, characterized in that the gripping piece (3) overlies with a portion (3'") thereof an upper contact-shoulder portion (2") on the retaining piece (2).

7.

A means for insertion of a shock-absorbing stud, as disclosed in one or more ofthe claims 1 -6, in a footwear sole, characterized by an internally threaded sleeve insert (16) which extends outward from a cavity (15) in the footwear outsole (14) via a hole (14') toward the outer surface ofthe outsole, said insert (16) being axially movable within the hole (14') and within the cavity (15), said insert (16) having a flange (16') situated in the cavity (15) and defining the movability ofthe insert toward said outer surface, and the threaded portion of said insert (10) being adapted to form threaded engagement with the threaded head (2') ofthe retaining piece (2).

8.

A sports footwear device, wherein a plurality of stud-shaped members (18) preferably in the approximate form of an inverted, truncated cone are incoφorated into the wearing surface ofthe sole, and wherein said members are formed as an integrally moulded part of the footwear outsole (19), characterized in that each of said members contains a prominent cavity (21; 22) situated axially opposite to the wearing surface (18') ofthe member with the opening thereof oriented toward the intermediate sole (20) ofthe footwear in order to absorb volume changes in the member (18) on application of impact/pressure loading against the wearing surface (18').

9.

A device as disclosed in claim 8, characterized in that the cavity (21 , 22) has a maximum diameter equal to or greater than the diameter ofthe stud (18), and that the stud (18) intergrally extends into the outsole (19) via an elastic, resilient transitional portion (23) curved in the direction outward from the intermediate sole (20).