Note: Descriptions are shown in the official language in which they were submitted.
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STUDDED FOOTWEAR
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.
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 several 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 moulded in, or otherwise secured to, the
shoe sole.
The screw-threaded connection must be designed to ensure that the stud
remains in place, even when high forces are applied, and in particular
that it does not unscrew accidentally. Known studs have either a single
start thread or a mufti-start thread. A single start thread is the simplest
thread form, and provides a greater resistance to unscrewing than a multi-
start thread. It also provides a strong connection over the several turns of
the thread on the spigot and socket. However, because of the number of
turns needed to attach and detach the stud, removal and replacement
becomes a time-consuming operation. A mufti-start thread has a steeper
helix angle, which enables a spigot of any given length to be inserted into
the socket with less rotation. Also, because a mufti-start thread is deeper
cut than a single start thread, the shear strength of the thread is greater,
so that a shorter spigot can be used.
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Whether a single start or mufti-start thread is used, the studs and sockets
also incorporate a locking ratchet to prevent accidental unscrewing of the
studs. Typically, the stud and socket each have a set of teeth, which
interengage as the stud is inserted into the socket. The arrangement of
the teeth allows the stud to be in any one of a number of positions relative
to the socket when it is fully inserted.
The screw threads and locking ratchets described are quite adequate
where the rotational orientation of the stud relative to the sole is not
significant. In fact, currently most studs are circular or otherwise
rotationally symmetrical, and their final orientation relative to the shoe
sole is 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. The known screw-threads
and locking ratchets are unable to provide this precise orientation. For
example, although a single start thread orients the stud at the start of its
insertion, the multiple turns and the locking ratchet mean that its final
position cannot be predicted. A mufti-start thread of course provides a
plurality of starting positions, and the locking ratchet a plurality of end
positions.
The invention aims to ensure that a stud can be oriented precisely
relatively to its socket and receptacle; orientation of the receptacle
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relative to the shoe sole is of course necessary, but does not form part of
this invention.
According to the present invention, in a combination of a shoe ~ stud arid
receptacle, the shoe stud includes a ground-engaging part and the two
components are adapted to be secured together by a multi-start threaded
connection comprising a screw-threaded spigot on one of the two
components adapted to be inserted with rotation into a screw-threaded
socket on the other component, and a locking means of the components
which is arranged to become interengaged at least when the spigot is fully
inserted into the socket to resist unscrewing of the components, the
locking means comprising at least one locking assembly, the arrangement
being such that the relative number and/or position of the threads of the
threaded connection and the locking assemblies determine the initial and
final positions of the stud relative to the receptacle.
As the initial and final orientation of the stud relative to the receptacle
are both determined, the stud can be specifically oriented relative to the
receptacle and hence to the shoe sole.
The multi-start threaded connection may have two, three or more starts,
to reduce the number of turns required to attach and detach the stud.
Both or all of the threads preferably have the same construction. The
initial position of the stud relative to the receptacle is then determined by
the number and/or positions of the locking assembly or assemblies. For
example, if the threaded connection is a two-start thread, there may be
three locking assemblies, positioned so as to allow the threaded
connection to engage when the stud is in one orientation, but to prevent
its engagement when the stud is in the opposite orientation, since the
locking assemblies are unable to start interengaging.
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A similar effect will be obtained if the threaded connection is a three-start
thread, and there are two or four locking assemblies. In general, the
threads and locking assemblies can easily be arranged to define the initial
position of the stud relative to the receptacle if the numbers of each are
relatively prime.
In an alternative construction, where there is more than one locking
assembly, one of the locking assemblies may have a different construction
from the other or others. This helps .to ensure that the initial position of
the stud relative to the receptacle is determined.
The locking means preferably comprises locking assemblies formed by
radially facing locking formations on the stud and receptacle operative to
interengage when the spigot has been screwed into the socket to a
predetermined axial position. One of the locking formations comprises at
least one radial projection, while the other comprises at least a radially-
facing lead-in ramp, recess and stop means. The projection rides over a
lead-in ramp before snapping into a recess, and then engages the stop
means to prevent the stud being screwed any further into the socket. The
locking assemblies allow the stud to be unscrewed on application of a
predetermined torque by resilient yielding of the locking formations. The
projections and lead-in ramps may be formed on axially-extending webs
surrounding the spigot or socket. The projection of one locking assembly
may have a greater axial extent than the other or others, with a
corresponding lead-in ramp of smaller axial extent. If this projection
engages with one of the other lead-in ramps, it will hold the threads on
the spigot and socket out of engagement, thus preventing insertion of the
threads at the wrong initial position.
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It is easy to arrange the locking assemblies circumferentially relative to
the threads to ensure the precise final orientation of the stud relative to
the receptacle. The stud may therefore be a specifically oriented stud,
and in particular a non-rotationally symmetrical stud.
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An embodiment of the invention is illustrated by way of example in the
accompanying drawings, in which
Figure 1 is a top plan view of a shoe stud;
Figure 2 is a perspective view of the stud of Figure 1;
Figure 3 is a side view of the stud of Figure 1;
Figure 4 is an underneath plan view of a receptacle for the stud of
Figures 1 to 3; and
Figure 5 is a perspective view of the receptacle of Figure 6.
Figures 1 to 3 show a stud 1 suitable for use on a sports shoe such as a
golf shoe (not shown) . The stud 1 is adapted to be inserted with rotation
and received in a receptacle 2, shown in Figures 4 and 5, which is
moulded into or otherwise attached to a sole or heel of the sports shoe.
The stud 1 is a unitary moulding of plastics material arid has a circular
flange 3 . Ground-engaging spikes 4 proj ect from the lower side of the
flange 3, while an externally screw-threaded spigot 5 projects from the
upper side. The spikes 4 are arranged to be non-rotationally symmetrical.
As the spikes 4 of the stud 1 are non-rotationally symmetrical, it requires
to be oriented in use relative to the shoe sole. Orientation of the stud 1 in
the receptacle 2 is the first stage of this.
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The external screw thread on the spigot 5 is a two-start thread 6 with a
relatively steep helix angle, so that the stud 1 can be inserted in the
receptacle 2 in approximately one-third of a turn. Because of the
relatively steep helix angle of the thread, the frictional resistance to
unscrewing of the stud 1 is relatively low. The stud 1 and receptacle 2
therefore have a locking means 7, which serves to secure the stud 1 in the
receptacle 2, as well as defining its initial and final position relative to
the receptacle 2.
The locking means 7 comprises three locking assemblies 8 having co
operating parts in the stud 1 and receptacle 2. The positions of the
locking assemblies 8 relative to the two threads 6 on the spigot 5 are
arranged to ensure that the stud 1 can only be inserted in one orientation,
thus defining the initial position.
The part of each looking assembly 8 provided on the stud 1 is a projection
9. Each projection comprises a part-cylindrical web 10 extending axially
from a ring 11 which itself projects axially from the flange 3, co-axial
with and radially spaced from the spigot 5. Each projection y has a
radially-outwardly extending locking projection as an axially-extending
rib 12 provided on the leading end (in the screwing-up direction) of the
web 10. The rib 12 is substantially rectangular in outline, projecting
perpendicularly from the cylindrical outer surface 13 of the web. The
trailing end 14 of the web is angled, so that the circumferential dimension
of the lower end of the web 10 where it j oins the ring 11 is greater than
the circumferential dimension at its upper end.
One of the projections 9' has a greater axial height than the other two,
extending for perhaps three-quarters of the axial height of the spigot 5.
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The axial height of the other two projections is about half that of the
spigot 5.
The receptacle 2 of Figures 4 and 5 is also a unitary moulding of plastics
material. It has a circular top plate 15 with a central boss 16 depending
from it. An annular anchoring flange 17 is formed by a portion of the
plate 15 projecting radially outward beyond the boss 16. The flange 17
has apertures 18 which assist in anchoring the flange 17 to the shoe sole
or heel, and an indentation 19 at one point in its periphery. The
indentation 19 is used to orient the receptacle 2 in the shoe sole or heel.
The boss 16 comprises a stout inner cylindrical wall 20 and a relatively
thin and slightly flexible outer wall 21. The walls 20, 21 are co-axial.
The inner wall 20 forms an internally screw-threaded socket 22 adapted to
receive the spigot 5. The socket 22 also has a two-start thread. The
radially outer surface 23 of the inner wall 20 and the radially inner
surface 24 of the outer wall 21 are spaced to define an annular space 25
between them, adapted to receive the webs 10 of the stud 1. The co
operating parts of the locking assemblies 8 are also accommodated in the
annular space 25.
The part of each locking assembly 8 provided on the receptacle comprises
a locking formation on the outer wall 21, formed on the inner surface 24
to face radially inwards. Each locking formation has a recess 26
bordered on one circumferential side by a lead-in ramp 27, and on the
other side by a stop 28. The ramps 27 extend round approximately one-
eighth of the circumference of the outer wall 21. Each stop 28 extends
from the inner surface 24 of the outer wall 21 to the outer surface 23 of
the inner wall 20. The maximum axial height of each ramp 27 is
approximately the same as that of its stop 28. Two of the ramps 27 and
stops 28 have an axial height of about three-quarters of that of the walls
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20, 21, while the third 27', 28' have a lesser axial height. This together
with the different axial heights of the projections 9, 9', assists in defining
the initial position of the stud 1 relative to the receptacle 2, as explained
in more detail below. The engagement of the projections 12 with the
stops 28 define its final position.
In use the receptacle 2 is incorporated in the sole or heel of a sports shoe.
Normally the receptacle 2 is moulded into the shoe sole or heel. Because
the stud 1 needs to be specifically-orientated, the receptacle 2 must also
be oriented precisely in the shoe sole or heel. The indentation 19 may be
used to orient the receptacle 2 in a mould.
The stud 1 is installed in the receptacle 2 by the insertion of the spigot 5
into the socket 22, with the projections 9 being received in the annular
space 25 at the same time. As the thread 6 on the spigot 5 is a two-start
thread, there are potentially two orientations in which it can engage with
the socket 22. The arrangement of the three locking assemblies 8
however force the stud 1 into one particular orientation, as in the other
orientation the projections 9 are prevented from entering the space 25 by
engagement with the axial faces of the stops 28. Further, if the
projection 9' engages with the stops 28 of greater axial height, the screw
threads on the spigot 5 and socket 22 will be held out of engagement; it is
only when the spigot 5 is in the correct initial position that the threads
can start to engage. Rotation of the stud 1 causes the spigot 5 to be
drawn into the socket 22, and the ribs 12 into the space 25. The
construction of the threads 6 is such that full insertion of the stud 1 takes
only about one-third of a turn. For the last part of the insertion
movement the locking projections 12 engage with the lead-in ramps 27,
and then snap into the recesses 26 between the ramps 27 and the stops 28.
Further rotation is therefore prevented by the engagement of the
projections 12 with the stops 28. The outer wall 21 deforms resiliently as
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the projections 12 ride over the ramps 2~, but returns to its original shape
when the projections 12 reach the recesses 26. As the projections 12 snap
into the recesses 26 they make a click, which can be felt and/or heard,
and signal that the insertion of the stud 1 is complete.
The final position of the stud 1 in the receptacle 2 is therefore determined
by the locking means 7.
It will be appreciated that the relative numbers and positions of the
threads 6 arid locking assemblies ~ can be changed, while still retaining
the ability to determine the initial and final positions of the stud 1 in the
receptacle 2. It would also be possible to employ a different type of
locking means (not shown) such as a ring of posts extending axially from
one of the components and a ring of radially projecting teeth on the other
component. As the spigot is screwed into the socket, engagement of the
teeth with the posts causes resilient deflection of the posts, and
engagement of the teeth between the posts causes interengagement of the
locking means. Of course, the posts and teeth must be arranged so that
they allow engagement if the threads in the socket and spigot in only one
orientation.
