Abstract:
An outsole for an article of studded footwear in which said outsole includes receptacles for specifically-oriented studs. The outsole also includes traction elements formed integrally with the outsole. The studs and traction elements being so constructed and arranged to interact in use of the footwear. The traction elements are designed to complement the spike configuration of the stud.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. patent application Ser. No. 10/409,185, filed 9 Apr. 2003 now U.S. Pat. No. 7,559,160 and entitled “Studded Footwear,” which claims priority under 35 U.S.C. §119 to U.S. Provisional Application No. 60/393,655, filed 5 Jul. 2002 and entitled “Studded Footwear,” as well as under 35 U.S.C. §119 to Application No. GB0208144.6, filed on 9 Apr. 2002 and entitled “Studded Footwear.” The disclosures of the aforementioned applications are hereby incorporated by reference in their entireties. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to studded footwear such as sports shoes, for example football boots and golf shoes. The term “football” is intended to encompass all sports known as football, such as soccer, rugby and American and Australian football. 
     BACKGROUND OF THE INVENTION 
     The studs are intended to provide traction, having a ground-engaging part of a type suited to the sport involved. Thus, studs for football tend to have relatively sharp ground-piercing spikes, while those for golf shoes currently have relatively soft and blunt ground-gripping spikes. The studs are detachably fastened to the sole of the article of footwear by a screw-threaded spigot on the stud engaging in a correspondingly threaded socket in a receptacle molded in, or otherwise secured to the shoe sole. The screw thread may be single start or multi-start, and the stud and socket may also incorporate a locking ratchet to prevent accidental unscrewing of the stud. 
     The studs provide most, if not all, of the traction for the footwear and may be of different kinds, even for one sport. Thus, golf studs may have dynamic spikes which flex when pressure is applied to them, or static spikes, which do not flex. A dynamic spike may not always flex in the manner intended, depending on the surface or the way the pressure is applied. 
     Previously, rotational orientation of the studs relative to the shoe sole was not necessary, as most studs are circular or otherwise rotationally symmetrical. Their final orientation relative to the shoe sole is therefore not relevant. 
     However, in some sports where the forces on the studs are relatively high and of a particular type, such as lateral forces or forces due to rapid forward acceleration of the wearer of the shoe, studs which are specifically-oriented can be more effective. The term “specifically-oriented stud” will be used to include studs which are non-rotationally symmetrical, or studs which are rotationally symmetrical, but whose orientation relative to the shoe sole is significant. A specifically-oriented stud must be oriented very precisely relative to the shoe sole to ensure that it operates in the desired manner. Most known screw threads and locking ratchets are unable to provide this precise orientation. We have devised a system of ensuring the precise orientation of the stud relative to the receptacle. Orientation of the receptacle in the sole then provides the precise orientation of the stud relative to the sole. 
     SUMMARY OF THE INVENTION 
     According to the present invention, an outsole for an article of studded footwear includes receptacles for specifically-oriented studs and traction elements formed integrally with the outsole, the studs and traction elements being so constructed and arranged to interact in use of the footwear. 
     The ability to provide precise orientation of the stud relative to the outsole means that the outsole can be designed with traction elements that work with the studs to improve the overall traction of the outsole. 
     Thus, where the studs for golf shoes include dynamic spikes, the traction elements may be formed on one or both circumferential sides of at least one spike. The traction elements can then guide the spikes as they flex, and also act as static or dynamic traction elements. The traction elements may extend at any appropriate angle from the outsole. They may be V-shaped or triangular in profile. 
     The traction elements will be designed to complement the spike configuration of a stud, which depends on the positioning of the stud in the outsole and the forces on the outsole in use. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An embodiment of the invention is illustrated by way of example in the accompanying drawings, in which: 
         FIG. 1  is an underneath plan view of an outsole for a golf shoe with one stud attached; 
         FIG. 2  is a side view of the stud of  FIG. 1 ; 
         FIG. 3  is a top plan view of a stud; 
         FIG. 4  is an underneath plan view of a receptacle; and 
         FIG. 5  is a scrap section along the line  5 - 5  of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The outsole  1  of  FIG. 1  is for a studded golf shoe. The outsole  1  is molded from rubber, and incorporates several receptacles  2 , which are molded into the outsole  1  in the appropriate arrangement on the sole  3  and heel  4 . Each receptacle  2  is adapted to receive a specifically-oriented stud  5  (only one of which is shown). The stud  5  has ground-engaging spikes  6  and the outsole  1  has integrally-formed traction elements  7 , which in use interact with the spikes  6 . 
     Each stud  5  is a unitary molding of plastics material, having a flange  8  with a screw-threaded spigot  9  projecting from a tipper side of the flange  8 , while the spikes  6  project from the lower side. There are three dynamic spikes  6   a , which flex when pressure is applied to them, and five static spikes  6   b , which do not. 
     The spigot  9  has a multi-start external screw thread  10 , with a relatively steep helix angle so that the stud  5  can be inserted in the receptacle  2  in half a turn. In order to define the initial position of the stud  5  relative to the receptacle  2 , one of the threads on the spigot  9  is different from the others so that the screw thread  10  can only be engaged in one position of the stud  5  relative to the receptacle  2 . 
     Because of the relatively steep helix angle of the thread, the frictional resistance to unscrewing of the stud  5  is relatively low. The stud  5  and receptacle  2  therefore have a locking means  11 , which comprises a ring of resilient posts  12  on the stud  5  co-operating with a ring of teeth  25  in the receptacle  2 , arranged so that engagement of the teeth with the posts causes resilient deflection of the posts, and engagement of the teeth between the posts inter-engages the locking means. This serves to secure the stud  5  in the receptacle  2  and to define its final position relative to the receptacle  2 . The stud  5  is then precisely oriented in the receptacle  2  when it is fully engaged. 
     The resilient posts  12  extend axially from the upper side of the flange  8 . They surround the spigot  9  and form a ring concentric with the spigot  9 . There are six posts  12  distributed uniformly about the axis of the stud. The axial extent of each post  12  is about half the axial height of the spigot  9 , and each post is radially resilient. The radially outer surface of each post  12  has a lower part-cylindrical portion  13  and an upper part-conical portion  14 . The top surface  15  of each post  12  is angled up towards the spigot  9 , so that the radially inner surface  16  of each post  12  has the greatest axial height. The radially inner surface  16  is generally convex towards the spigot  9 , with a central convex region  17 , a first circumferential end  18  having a concave profile towards the spigot  9 , and a second circumferential end  19  having a convex profile towards the spigot  9 . The first end  18  is the leading end and the second end  19  the trailing end on insertion of the stud  5 , and vice versa when it is removed. The concave profile of the first end  18  presents less resistance on insertion of the stud, while the convex profile of the second end  29  presents greater resistance on removal. 
     The receptacle  2  is also a unitary molding of plastics material. It has a circular top plate  20  with a central boss  21  depending from it. The receptacle  2  is anchored in the outsole  1  by the top plate  20 , which may include means (not shown) for ensuring that the receptacle  2  is precisely oriented relative to the outsole  1 . 
     The boss  21  has a stout cylindrical wall  22 , whose inside forms an internally screw-threaded socket  23  adapted to receive the spigot  9 . The socket  23  also has a multi-start thread, with one of the grooves being different from the others, to complement the different thread  10  in the spigot  9 . The radially outer surface  24  of the boss  21  is formed with the other part of the locking means  11 , as the ring of axially-extending teeth  25 , projecting radially outwards from the surface  24 . In cross-section, the teeth  25  are generally triangular, but with a rounded apex. 
     The distance of radial projection of the teeth  25  from the socket axis is substantially equal to that of the inner surfaces of the posts  12  at the first end  19 . There is therefore radial interference between the teeth  25  and posts  12 , which causes frictional resistance to relative rotation of the stud  5  and receptacle  2 . 
     The stud  5  is installed by the insertion of the spigot  9  into the socket  23 . Because of the different thread  10  and groove, there is only one position in which the screw-threaded connection can engage. As the spigot  9  is rotated it is drawn into the socket  23 , and the teeth  25  engage with the posts  12 . The posts  12  deflect radially in a resilient manner to allow the teeth  25  to move past the posts  12 . Once the spigot  9  has rotated through 180°, the stud  5  is fully inserted in the receptacle  2 , and is secured by the inter-engagement of the teeth  25  and posts  12 . 
     Thus, the position of the stud  5  in the receptacle  2  is precisely determined by the screw thread and the locking means  11 . As the position of the receptacle  2  relative to the outsole  1  is also precisely determined, the spikes  6   a ,  6   b  of the stud  5  will be in a precisely determined position relative to the outsole  1 , so that in use they can interact with the traction elements  7  on the outsole  1 . 
     As shown in the Figures, four traction elements  7  are provided, so that there is one on each circumferential side of each dynamic spike  6   a . Each traction element  7  is of substantially triangular form and projects from the outsole  1 . The axial height of each traction element  7  is less than the axial extent of the dynamic spikes  6   a . The elements  7  shown project substantially at right angles to the outsole  1 , but may be at any suitable angle. 
     In use, when the shoe is worn, the weight of the wearer in the shoe causes the dynamic spikes  6   a  to flex radially outwards. Their movement is guided by the traction elements  7 , which then also come into engagement with the ground to provide extra traction, as static spikes. 
     It will be appreciated that the construction and arrangement of the traction elements  7  will be designed to complement the studs  5  which are used. The traction elements  7  may therefore have different forms, and act dynamically or statically. It will also be appreciated that different thread forms and locking means may be used on the stud and receptacle, as required.