WO1992011781A1

WO1992011781A1 - Studs for footwear

Info

Publication number: WO1992011781A1
Application number: PCT/GB1991/002315
Authority: WO
Inventors: Paul Andrew Kelly
Original assignee: Trisport Ltd
Current assignee: Trisport Ltd
Priority date: 1991-01-04
Filing date: 1991-12-23
Publication date: 1992-07-23
Anticipated expiration: 1993-07-04
Also published as: GB9100112D0

Abstract

A stud comprises a ground-engaging portion (6) and a spigot (7) which is adapted to become permanently secured, upon insertion, in a plain cylindrical socket provided by a plastics member (3) incorporated into a shoe. The stud comprises a plurality of frusto-conical rings (8) which present sharp edges (21), there being notches (22) in the rings which divide them into discrete teeth or barbs (23). Upon axial insertion of the spigot into the socket the plastic of the socket wall deforms but relaxes sufficiently to occupy spaces between the rings, subsequent withdrawal of the stud so being prevented by the teeth or barbs (23). The stud is an assembly of components comprising a central steel spike (10), a flange disc (9) and a retaining collar (14), and upper end lip (16) of the spike being rolled over to secure the assembly.

Description

STUDS FOR FOOTWEAR

This invention relates to studs and their securement in footwear, and to footwear incorporating studs.

For convenience of description the term stud is used herein in a generic manner, therefore including both blunt projections and sharp or sharper projections of the kind sometimes referred to as spikes.

Also, for convenience of description, both studs and articles of footwear are described herein as if they are in the orientations they would normally assume when in use.

A widely used kind of stud comprises a ground-engaging portion and an upwardly projecting spigot which is externally screw-threaded. A stud of that kind is described and illustrated, for example, in GB-A-2 028 102. Studs of that kind are used with articles of footwear provided with downwardly opening sockets that are formed with internal screw-threads complementary to those on the spigots. Sockets for articles of footwear are described and illustrated in, for example, GB-A-1 564 903 and GB-A-2 115 683. Such studs are installed by screwing their spigots into the sockets. A variety of means has been proposed and used to prevent, as far as possible, the studs becoming partially or wholly unscrewed in use, while permitting worn or damaged studs to be unscrewed and replaced with new ones. While such studs and sockets have proved to be successful in practice, they are relatively difficult and costly to manufacture, particularly as they must be manufactured to high tolerances. An object of the present invention generally is to provide an improved stud-and-socket system for articles of footwear.

From a first aspect the present invention provides a socket-forming member for incorporation into an article of footwear and a complementary stud for permanent or semi-permanent retention in the socket, the stud comprising a downwardly-projecting ground-engaging portion and an upwardly-projecting spigot for insertion into the socket, and the spigot being provided externally with projecting formations which are arranged to bite into a deformable surrounding wall portion of the socket-forming member upon insertion into the member to achieve a tight interengagement between the spigot and the member which holds the stud firmly in place and prevents ready withdrawal of the spigot.

At least the deformable wall portion of the socket-forming member may be of a plastics material. The member may be one of a plurality of such members formed by a single moulded plastics unit to be incorporated into an article of footwear.

The invention is based on the principle that the socket wall is not conformed, or is not fully conformed, into a complementary shape with the stud spigot until the spigot is inserted into it, the projecting formations on the spigot forming or completing complementary formations in the boundary surface around the socket.

Use of the invention can lead to the advantage that the stud is still held firmly in place, owing to the frictional and other forces acting between the spigot and the socket, even if the spigot is not driven fully home during its installation or if the spigot becomes slightly displaced in use.

Another advantage that can result from the use of the present invention is that the tolerances to which the parts are manufactured need not be so stringent as was generally required in the manufacture of studs and sockets of previous designs.

The interior of the socket (prior to insertion of the spigot) is preferably bounded by a smooth and non-recessed boundary surface, which may be of substantially cylindrical shape.

The invention can also lead to the advantageous consequence that there is no need for the spigot and socket to be in any predetermined rotational relationship before the spigot is inserted into the socket.

At least the ground-engaging portion of the stud is preferably sufficiently wear-resistant to enable the stud to be usable throughout the life of the article of footwear. To that end, at least the ground-engaging portion may be of a sintered, wear-resistant material, for example a material comprising tungsten carbide and/or cobalt.

From a second aspect the present invention provides a method of permanently or semi-permanently securing a stud in a socket of a socket-forming member for incorporation into an article of footwear in which the stud comprises a spigot which is provided externally v/ith projecting formations which are arranged to bite into a deformable surrounding wall portion of the socket-forming member upon insertion into the socket, a tight interengagement between the spigot and the socket-forming member being achieved which holds the stud firmly in place and prevents ready withdrawal of the spigot.

The formations on the stud spigot preferably comprise a plurality of projecting teeth or barbs which are distributed about the spigot and are shaped to bite into the socket wall to resist withdrawal of the spigot from the socket. Preferably, the spigot is adapted to be inserted into the socket by application of an axially directed force, substantially without rotation of the stud.

From a third aspect the present invention provides a stud for permanent or semi-permanent engagement in a complementary socket of a socket-forming member incorporated into an article of footwear, the stud comprising a downwardly-projecting ground-engaging portion and an upwardly-projecting spigot for insertion into the complementary socket, and the spigot being provided externally with projecting formations comprising a plurality of teeth or barbs which are distributed about the spigot and are shaped to bite into a smooth and un-recessed deformable socket wall to resist withdrawal of the spigot from the socket.

There now follows a detailed description, to be read with reference to the accompanying drawings, of two embodiments which illustrate the invention by way of example.

In the accompanying drawings: Figure 1 is a vertical section through part of an article of footwear showing a first arrangement of stud and socket; and

Figure 2 shows a similar arrangement to Figure 1 but in which an alternative form of stud is employed.

The same reference numerals have been used in Figures 1 and 2 for corresponding features in the two arrangements.

As shown in both Figures 1 and 2, a shoe includes an outsole 1 made of leather. A plurality of holes 2 are formed through the outsole, one such hole being illustrated. The hole 2 houses a socket-forming member 3 which fits tightly within the hole. The member 3 is initially provided with a plain (smooth and un-recessed) cylindrical bore, open at its lower end, and forms part of a socket unit which provides a plurality of such sockets, and a plate 4 from which the sockets depend. The plate 4 may be imperforate or may be formed with openings, as desired. The socket unit is formed as a unitary moulding of a suitable plastics material such as an acetal resin. As the bores of the sockets are initially cylindrical the unit can readily be moulded in a simple two-part mould. When the unit is incorporated in a shoe during manufacture, each socket-forming member 3 fits tightly within a corresponding hole in the outsole. The outsole may not be of exactly uniform thickness throughout but the arrangement is preferably such that the lower ends of the socket-forming members are substantially flush with the lower ends cf the holes 2, or just accommodated within the holes. In the completed shoe, the assembled socket unit and outsole are covered by a thin insole (not shown) .

A stud 5 is illustrated as having been assembled with the socket. The stud has a downwardly-projecting ground-engaging portion 6 of tapered shape with a rounded tip. It also includes an upwardly-projecting spigot 7 of generally cylindrical shape but formed on its outer surface with projecting retaining formations 8. Between the ground-engaging portion 6 and the spigot 7 there is an outwardly directed flange disc 9 of dished shape.

In manufacture of the stud 5, a central spike 10 is formed which provides both the ground-engaging portion 6 and an upwardly-extending cylindrical pin 11. At the upper end of the ground-engaging portion, the spike is flared outwardly to form an upwardly-facing annular shoulder 12 extending around the lower end of the pin 11.

The flange disc 9 of the stud is provided by a separate element having a central bore 13 which enables it to be slid down the pin 11 to abut the shoulder 12. A tubular stud-retaining collar 14 is next assembled on to the pin to abut at its bottom end an upper surface 15 of the disc; the flange disc 9 and the collar 14 are both sliding fits with the pin 11. To secure the stud assembly together, an annular lip 16 around a hollowed upper end portion of the pin 11 is rolled over (radially outwards) to overlie a frusto-conical upper end face 17 of the collar 14, the flange disc 9 and the collar 14 so becoming secured axially between the shoulder 12 and the out-turned The spike can be made in any suitable manner and of any suitable material or combination of materials, bearing in mind a need to give the ground-engaging portion 6 a high degree of wear-resistance whilst the lip 16 must be rollable over to secure the spike assembly. [Composite spike constructions are known in the art, for example as described in GB-A-1277684 wherein a tungsten carbide ground-engaging tip is cemented on to a steel body.]

The flange disc 9 may be of metal or plastics, or any other suitable material.

The stud-retaining collar 14 is of metal, though it could be of any suitably hard material as compared with the plastics material of the socket-forming member 3. The collar shown in Figure 1 comprises externally a series of axially-equispaced circumferential rings of uniform over all diameter. Each ring is formed by an upwardly-convergent frusto-conical portion 18 of the collar, presenting a flat annular under-surface 19 and a conical outer surface 20, the two surfaces meeting at a sharp circular edge 21. Notches 22 are cut into the rings to interrupt the edges 21 at regular intervals about the axis, so in effect dividing peripheral portions of the rings into discrete teeth or barbs 23 which form the stud-retaining formations 8.

When the stud 5 of the construct ■on shown in Figure 1 is to be installed, the upper end of the spigot 7 is inserted into the lower end of the socket and the stud is pushed axially into the socket. The stud is preferably introduced into the socket by cold insertion (rather than, for example, necessitating generating heat by ultrasound to cause localised softening of the plastics wall to ease insertion) . The stud enters the socket substantially without rotation, no effort being made to cause rotation and the teeth or barbs 23 not be directed to induce rotation. The stud is driven in until the rim of the flange disc 9 presses into the outsole 1 or until an inner part of the flange disc abuts the lower end of the socket-forming member.

It is preferred to arrange for a narrow gap to remain between the top of the spigot and the closed upper end of the socket.

As the stud is driven into the socket, the rings of the teeth or barbs 23 bite into the material of the plastics wall bounding the socket. The material has some resilience and relaxes to fill (partially at least) the spaces behind the rings. The stud so becomes locked into the socket, there being a tight interengagement between the stud spigot and the socket-forming member 3 which holds the stud firmly in place. The teeth or barbs 23 are shaped to prevent withdrawal of the spigot and the stud is effectively permanently installed in the socket; if the stud were to be pulled out of the socket the teeth or barbs 23 would ordinarily do such damage to the socket wall as to render the socket non-reusable.

It is intended that once the stud has been installed it should remain permanently in place and should last until the entire shoe is discarded.

To achieve similar results, a stud comprising a different form of retaining collar 14 is shown in Figure 2. In this alternative construction, the collar comprises externally a single helical flight 24, instead of the series of rings of the first embodiment. To install this stud into the socket it is both pushed axially and encouraged to rotate. The flight 24 acts in a self-tapping manner, deforming the boundary wall around the socket to form a corresponding thread. The interengagement between the stud spigot and the socket member 3 is tight, and the stud is not provided with any formations which would ease removal by unscrewing. Further, to resist any tendency that there might be for the stud to rotate and work its way out of the socket, suitably shaped notches or barbs may be formed to interrupt the flight 24. Once again, it is intended that the stud should remain permanently in place and last for the life of the shoe.

Claims

1. A socket-forming member (3) for incorporation into an article of footwear and a complementary stud (5) for permanent or semi-permanent retention in the socket, the stud comprising a downwardly-projecting ground-engaging portion (6) and an upwardly-projecting spigot (7) for insertion into the socket, and the spigot being provided externally with projecting formations (8) which are arranged to bite into a deformable surrounding wall portion of the socket-forming member upon insertion into the member to achieve a tight interengagement between the spigot and the member which holds the stud firmly in place and prevents ready withdrawal of the spigot.

2. A socket and stud combination according to claim 1 in which at least the deformable wall portion of the socket-forming member (3) is of a plastics material.

3. A socket and stud combination according to either of claims 1 and 2 in which the wall portion of the socket-forming member provides a continuous boundary surface around the socket which is smooth and non-recessed prior to insertion of the stud spigot into the socket.

4. A socket and stud combination according to any one of claims 1, 2 and 3 in which the formations (8) on the stud spigot (7) comprise a plurality of projecting teeth or barbs (23) which are distributed about the spigot and are shaped to bite into the socket wall to resist withdrawal of the spigot from the socket.

5. A socket and stud combination according to any one of the preceding claims in which the formations (8) on the stud spigot (7) and the form of the socket are such that the spigot is adapted to be inserted into the socket by application of an axially directed force substantially without rotation of the stud.

6. A stud (5) for permanent or semi-permanent engagement in a complementary socket of a socket-forming member (3) incorporated into an article of footwear, the stud comprising a downwardly-projecting ground-engaging portion (6) and an upwardly-projecting spigot (7) for insertion into the complementary socket, and the spigot being provided externally with projecting formations (8) comprising a plurality of teeth or barbs (23) which are distributed about the spigot and are shaped to bite into a smooth and un-recessed deformable socket wall to resist withdrawal of the spigot from the socket.

7. A method of permanently or semi-permanently securing a stud (5) in a socket of a socket-forming member (3) for incorporation into an article of footwear in which the stud comprises a spigot (7) which is provided externally with projecting formations (8) which are arranged to bite into a deformable surrounding wall portion of the socket-forming member upon insertion into the socket, a tight interengagement between the spigot and the socket-forming member being achieved which holds the stud firmly in place and prevents ready withdrawal of the spigot.

8. A method according to claim 7 in which the stud is inserted by application of an axially directed force substantially without rotation of the stud. AMENDED CLAIMS

[received by the International Bureau on 14 May 1992 (14.05.92); original claims 1 and 7 amended; other claims unchanged (2 pages)]

1. A socket-forming member (3) for incorporation into an article of footwear and a complementary stud (5) for permanent or semi-permanent retention in the socket, the stud comprising a downwardly-projecting ground-engaging portion (6) and an upwardly-projecting spigot (7) for insertion into the socket, and the spigot being provided externally with projecting formations (8) which are arranged to bite into a deformable surrounding wall portion of the socket-forming member upon insertion into the member, a tight interengagement between the spigot and the member being achieved and the engagement of the projecting formations with the socket-forming member preventing ready withdrawal of the spigot.

6. A stud (5) for permanent or semi-permanent engagement in a complementary socket of a socket-forming member (3)incorporated into an article of footwear, the stud comprising a downwardly-projecting ground-engaging portion (6) and an upwardly-projecting spigot (7) for insertion into the complementary socket, and the spigot being provided externally with projecting formations (8) comprising a plurality of teeth or barbs (23) which are distributed about the spigot and are shaped to bite into a smooth and un-recessed deformable socket wall to resist withdrawal of the spigot from the socket.

7. A method of permanently or semi-permanently securing a stud (5) in a socket of a socket-forming member (3) for incorporation into an article of footwear in which the stud comprises a spigot (7) which is provided externally with projecting formations (8) which are arranged to bite into a deformable surrounding wall portion of the socket-forming member upon insertion into the socket, a tight interengagement between the spigot and the socket-forming member being achieved and the engagement of the projecting formations with the socket-forming member preventing ready withdrawal of the spigot.

8. A method according to claim 7 in which the stud is inserted by application of an axially directed force substantially without rotation of the stud.