Note: Descriptions are shown in the official language in which they were submitted.
CA 02685885 2009-11-02
WO 2008/139019 PCT/F12007/000127
CONSTRUCTION FOR A SKI BINDING AND A SKI BOOT
FIELD OF THE INVENTION
The invention relates to the construction for
a ski binding and a ski boot for coupling the ski boot
to the ski as defined in the preamble of claim 1.
BACKGROUND OF THE INVENTION
Known in cross-country skiing is a wide vari-
ety of different ski binding and ski boot construc-
tions. What they all have in common is the coupling of
the foot to the ski such that the kick power cannot be
used to the maximum. Similarly, the natural function-
ing of the foot area has become almost impossible. An
anatomically correct motion for a human is a rolling
pace, such as during walking or running. In a natural
advancement, the last parts of the foot area which
touch the ground are thereby the toes, not the tips of
the toes. In known ski bindings, this rolling motion
has been prevented. Firstly, during the exertion
phase, the movement of the foot has been so limited
that the force which provides the grip to the exertion
begins to decrease a moment before the final stage of
the exertion, such that the ski may easily slip from
under the foot. Secondly, the rolling motion of the
foot area is prevented by a flexible element posi-
tioned in front of the boot, which limits the natural
movement of the foot area for continuing the rolling
pace.
A known technique in the field of the inven-
tion is disclosed for example in patent publication
US5228714 which describes a ski binding for classic
skiing style. The boot is coupled to the binding by
means of a transverse coupling shaft which is substan-
tially coupled to the tip of the boot. In different
known bindings, this may be positioned slightly under
CA 02685885 2009-11-02
WO 2008/139019 PCT/F12007/000127
2
the tip, just to the tip, or in front of the tip. The
coupling shaft forms a support point between the boot
and the ski right at the tip of the boot, such that
only the tips of the toes contact the binding as the
foot area rises. In practice, this causes the entire
foot area being raised such that the controllability
of the ski becomes unstable. Similarly, toward the fi-
nal stage of the kick, as the heel rises, the pressure
applied to the toes increases, causing pain and black-
ened toes. If instead one selects a larger boot, the
controllability becomes even worse.
When the boot is coupled at the front section
of the toes, the foot area rises during the final
stage of the kick almost entirely off the ski. In this
case, the kick force is transmitted almost entirely
forward, and the force directed downward and providing
the grip is left quite marginal. This results in the
need for using grip wax on a relatively long portion
along the length of the ski base.
Known from patent N0309845 is a ski binding
in which the rotation point has been shifted backward
under the toes. However, the construction comprises a
wedge-shaped space which opens up and forward, in
which space a flexible element is placed between the
ski and the tip of the boot. If the toes reach up to
the tip of the boot, they become bent upward in an un-
natural position for effective skiing. The flexible
element used in the wedge-shaped space limits the kick
and directs forces to a wrong direction. Although the
solution improves controllability, it has many defi-
ciencies as to the production of force, and at the
same time critically limits the natural movement of
the foot area and the toes.
Due to the instable controllability, the
binding constructions described above are not suitable
for skate style skiing; instead a binding application
has been developed therefore, manufactured by Salomon,
CA 02685885 2009-11-02
WO 2008/139019 PCT/F12007/000127
3
wherein, in addition to the coupling at the front sec-
tion of the toes, the boot is supported on the ski un-
der the ball of the foot by means of a mechanism which
limits the lifting of the boot from the ski to a spe-
cific angle. The application serves as a controlling
construction, but it does not provide any appreciable
improvement to correcting the direction of the kick.
The same problems emerge in another binding developed
for skate style skiing, manufactured by Rottefella,
which seeks to obtain rigidity by modifying the rigid-
ity of the flexible element positioned in front of the
boot, and by reinforcement of the sole of the boot.
According to what has been presented above,
the greatest problem of the ski bindings of the prior
art, regardless of the skiing style, is their inabil-
ity to provide an effective kick, which results from
the wrong direction, timing, and duration of the kick
forces. A further problem concerns movements which are
unnatural to the anatomy of the human foot and compli-
cate the control of the forces, prevent their effec-
tive use and cause injuries to skiers.
OBJECTIVE OF THE INVENTION
The objective of the invention is to elimi-
nate the drawbacks referred to above.
One specific objective of the invention is to
disclose a novel coupling of a ski boot to a ski bind-
ing, such that the kick force can be directed opti-
mally, the force maintained as long as possible, and
the movements of the foot with respect to the ski di-
rected as naturally for the human foot as possible.
SUNIIKARY OF THE INVENTION
The construction for a ski binding and a ski
boot in accordance with the invention is characterized
by what has been presented in claim 1.
CA 02685885 2009-11-02
WO 2008/139019 PCT/F12007/000127
4
The construction for a ski binding and a ski
boot in accordance with the invention is designed for
coupling a ski boot from its front section to a ski
and allowing the lifting of 'the heel section of the
ski boot from the ski. The ski binding comprises a
coupling mechanism for coupling the ski boot to the
binding. The ski boot comprises a transverse rotation
axis coupled to the sole thereof, the axis being per-
pendicular to the longitudinal direction of the sole,
for coupling the ski boot by means of the coupling
mechanism to an axial locking provided on the ski. The
sole of the ski boot comprises a toe section, a ball
section, an arched section, and a heel section. In ac-
cordance with the invention, the rotation axis is cou-
pled to the sole of the boot such that the toe section
of the sole of the boot is positioned in front of the
rotation axis. Also according to the invention, the
area under the toe section of the sole and in front of
the rotation axis and the axial locking, below the
horizontal plane defined by the rotation axis, com-
prises a substantially free space in which the toe
section of the sole of the ski boot is able to bend
down when the boot is bent about the rotation axis
when lifting the heel section from the ski.
It should be noted that in this application,
the rotation axis and the axial locking do not neces-
sarily mean a concrete, straight and rigid axle and a
corresponding groove; instead the terms should be un-
derstood as being used in the general sense. Therefore,
the substantial feature is an articulated, rotating
coupling between the sole of the boot and the soleplate
or between the sole of the boot and the ski, which al-
lows the rotation of the sole of the boot with respect
to the ski or to the soleplate in a hinge-like manner
about a specific, concrete or imagined, rotation axis.
In one embodiment of the invention, the sub-
stantially free space is formed by a recess formed in
CA 02685885 2009-11-02
WO 2008/139019 PCT/F12007/000127
the soleplate and, therefore, possibly in the ski as
well. In this case, the sole of the ski boot can be
substantially linear in the longitudinal direction.
In a second embodiment of the invention, the
5 substantially free space is formed partly by the shape
of the soleplate and partly by the shape of the toe
section in the sole of the boot.
In a third embodiment of the invention, the
substantially free space is formed by a recess in the
ski structure. In this case, it is, of course, also
possible that the space is partly formed by the shape
of the toe section of the sole.
The rotation axis may preferably be posi-
tioned 20-80mm backwards from the front tip of the ski
boot. In one embodiment, it is positioned at a dis-
tance of 30-60mm from the front tip of the ski boot,
the preferable distance being about 40-50mm. It is, of
course, natural that the above-mentioned distance can-
not be set as a specific number of millimeters; in-
stead it varies according to the skier's boot size,
i.e. substantially according to the length of the
skier's toes.
Therefore, the position of the rotation axis,
as well as the limit between the toe section and the
ball section, may be defined as being substantially
under the first joint of the hallux of the skier's
foot. Said limit may also be defined such that the toe
section is the front section of the sole of the boot,
to which the force applied downward by the toes is
substantially entirely directed, i.e. more specifi-
cally, the area on which the three biggest toes are
pressed as the heel is raised in the air.
In one embodiment of the invention, the rota-
tion axis which is straight and perpendicular to the
longitudinal direction of the ski and the sole of the
ski boot cuts the arched line between the toe section
and the ball section. Since the arched line, departing
CA 02685885 2009-11-02
WO 2008/139019 PCT/F12007/000127
6
from the root of the hallux, arches backward toward
the other edge, the areas covering the biggest toes in
the toe section of the sole of the ski boot are posi-
tioned in front of the rotation axis. The pressing
force of the skier's toes, i.e. the force applied from
the skier's foot to the toe section of the sole, is
thus directed downward mainly in front of the rotation
axis.
The space in front of the rotation axis may
be completely open, such that the toe section of the
sole of the ski boot is able to freely bend in that
area during a kick without any friction. In this case,
however, the movement of the ski boot easily becomes
insensitive and difficult to control. The space is,
therefore, preferably only substantially open, i.e.
free, i.e. a suitable elastic flexible element or
other suitable elastic construction is placed therein,
which element, when having a suitable contact to the
bottom of the space and to the toe section of the sole
of the ski boot, entirely prevents any frictionless or
free bending of the boot.
Although any spring construction, bellow con-
struction, air chamber, or other solution having suf-
ficient flexibility can be used as the flexible ele-
ment, it is preferably realized by means of a suitably
elastic rubber or plastic element which, compressing
for example for 50-80% and then reassuming its origi-
nal shape, allows the ski boot to establish a suffi-
ciently large rotation angle about its rotation axis.
The flexible element may fill the entire
space, or it may be so formed that it covers only a
portion of the space volume. It is also possible that
it protrudes out of the space, but the portion protrud-
ing out is not substantially significant for the func-
tioning of the flexible element. The protruding portion
may be used, for example, for coupling the element to
the ski binding.
CA 02685885 2009-11-02
WO 2008/139019 PCT/F12007/000127
7
One preferred embodiment of the invention
comprises several flexible elements which can be cou-
pled to the ski binding and differ from each other by
their elastic properties. This enables the use of the
same bindings in different skiing conditions and when
skiing in both classic style and skate style just by
changing a flexible element with different elastic
properties to the binding.
Because the rotation axis used for locking
the ski binding in accordance with the invention is
not positioned at the tip of the boot, but instead
clearly on the rear of the toe section, to some extent
even on the ball area, the locking provides a signifi-
cantly better and firmer horizontal torsional rigidity
to the boot with respect to the ski than the tradi-
tional locking mechanisms right at the tip of the
boot. Even so, one or more guiding ridges positioned
along the length of the ski and directed backward from
the axial locking can preferably be used on the sole-
plate. These ensure, especially in skate style skiing,
that the boot is held in place during the start phase
of the kick.
In the construction for a ski binding and a
ski boot in accordance with the invention, the sub-
stantial feature is that the front section of the
boot, i.e. the toe section of the sole, bends down and
moves substantially in a vertical direction in front
of the locking of the boot, i.e. the rotation axis.
The lever formed by the toe section in front of the
rotation axis can be pressed down by the toes during
normal, natural skiing to intensify the increase in
pressure caused by the bending of the boot. This re-
sults in achieving a significantly more effective
pressure between the ski and the snow than with the
known solutions, and at the same time obtaining a bet-
ter and easier grip than before. In this solution, the
entire grip zone of the ski is in contact with snow
CA 02685885 2009-11-02
WO 2008/139019 PCT/F12007/000127
8
also during the final phase of the kick, providing a
better grip than with the known constructions.
In the construction in accordance with the
invention, the free space formed under the front sec-
tion of the boot, i.e. the toe section, allows the
front section of the foot, i.e. the toes, to be
pressed below the rotation axis, enabling therefore
the establishment of a rolling pace for the first time
in the history of skiing. The movement of the foot in
this case is natural, and even when moving in a walk-
ing-like manner, the grip zone of the ski is effi-
ciently pressed against snow, improving even further
the grip of a grip-waxed ski. The movement of the foot
directs the force efficiently and correctly.
Compared to prior art, the binding construc-
tion in accordance with the invention has many sig-
nificant advantages: it is firmer and therefore safer;
it has a better controllability; it provides a better
and more precise grip, so that the grip zone of the
base can be shortened and the slide zone lengthened;
the improved sliding saves energy; due to better con-
trollability, the ankle joints do not become stressed;
a more effective use of the foot area and toes adds
power to the kicks and improves blood circulation in
the foot area; the increased force and more optimal
direction of the kick improve skiing efficiency; and
the same binding construction can also be used, only
by changing the elastic element, in boots of different
sizes, in cross-country skiing and skate style skiing,
as well as in touring and telemark skiing. The binding
construction in accordance with the invention provides
a natural way of moving on skis, and a more effective
and firmer kick, thus saving energy for the skier.
CA 02685885 2009-11-02
WO 2008/139019 PCT/F12007/000127
9
LIST OF FIGURES
In the following, the invention will be de-
scribed in detail by means of examples with reference
to the accompanying drawings, in which
Fig. 1 represents a schematic side view of
one ski binding and ski boot in accordance with the
invention,
Fig. 2 represents a more detailed top view of
the embodiment of Fig. 1,
Fig. 3 represents a more detailed side view
of the embodiment if Fig. 1,
Fig. 4 represents a schematic side view of
one embodiment of the invention,
Fig. 5 represents a schematic side view of a
second embodiment of the invention,
Fig. 6 represents a schematic side view of a
third embodiment of the invention,
Fig. 7 represents a schematic side view of
the fourth embodiment of the invention,
Fig. 8 represents a power curve indicating
the efficiency of the invention in skate style skiing,
and
Fig. 9 represents a power curve indicating
the efficiency of the invention in classic style ski-
ing.
DETAILED DESCRIPTION OF THE INVENTION
Fig. 1 represents a schematic side view of
the construction for a ski boot and a ski binding in
accordance with the invention. A soleplate 3 of the
ski binding is coupled to a ski 2, the front section
of which soleplate comprises a coupling mechanism 4,
such as a push button, a lever mechanism, a compres-
sion spring, or some other known construction, for
coupling a ski boot 1 to the binding. The ski boot 1
is coupled at the sole to the ski binding, the sole
CA 02685885 2009-11-02
WO 2008/139019 PCT/F12007/000127
being formed, in the order backwards from the tip, by
a toe section 7, a ball section 8, an arched section 9
and a heel section 10. An axis which is transverse
with respect to the longitudinal direction of the ski,
5 i.e. a rotation axis 5, is coupled substantially at
the junction of the toe section 7 and the ball section
8 to the sole of the ski boot for coupling the ski
boot to the soleplate 3. The corresponding position on
the soleplate 3 comprises an axial locking 6, a con-
10 struction known in the art per se, wherein a groove
which is shaped to correspond to the rotation axis
comprises locking shoulders which hold the axis in
place in the groove. The locking shoulders are con-
nected in a known manner to the coupling mechanism on
the front section of the ski binding, from which cou-
pling mechanism the locking can be opened for example
by pushing a button.
Figs. 2 and 3 comprise a more detailed de-
scription of the ski binding and the functioning
thereof in accordance with one embodiment of the in-
vention. The binding comprises a soleplate 3 for the
ski binding, which soleplate is coupled to a ski 2,
the front section of the soleplate comprising a cou-
pling mechanism 4 which is connected, via a coupling
18 indicated in dashed line, to an axial locking 6,
positioned farther back in the binding. The locking is
formed by a partially open-top groove in which a
straight axis stub of a suitable size can be pressed
to a locked-up position.
The area on the soleplate 3 between the axial
locking 6 and the coupling mechanism 4 is mainly
formed as a straight surface 19 which slopes down to-
ward the coupling mechanism, both edges of which sur-
face comprising on the soleplate even and horizontal
rims 20. On the straight sloping-down surface 19, a
wedge-shaped flexible element 15 of substantially the
size of the surface is placed, which element is made
CA 02685885 2009-11-02
WO 2008/139019 PCT/F12007/000127
11
from a suitable elastic material, for example rubber.
One edge of the flexible element 15 is positioned near
the axial locking 6, from which the element extends
forward towards the coupling mechanism 4, growing in
diameter as it extends, the growth being stronger than
the downward sloping of the surface 19. The upper sur-
face of the flexible element 15 is thereby formed to
slope upwards from the axial locking 6 toward the cou-
pling mechanism 4.
The front section of the sole of the boot 1
which is coupled to the ski binding comprises the toe
section 7 and the ball section 8. The toe section 7 of
the sole is bent somewhat upward, such that it is par-
allel to the upper surface of the flexible element 15
and rests against it, whereas the ball section 8 is
parallel to the soleplate 3 of the binding. A trans-
verse rotation axis 5 is coupled to the area between
the toe section and the ball section on the sole of
the ski boot, which axis can be pressed and locked in
the corresponding groove in the axial locking 6. The
locking can be released by means of a press or a
lever, not shown in the figure in any detail, provided
in the coupling mechanism 4.
The construction for a ski binding and a ski
boot in accordance with the invention increases, dur-
ing the kick phase, in both skate and classic styles,
the production of force to the rotation point, because
the leverage of the toe section directs the force to
the right direction, i.e. more downward. This improves
the production and direction of force, and the maneu-
verability and control of the ski, compared to the
prior art.
During skiing, the toe section 7 of the sole
in front of the rotation axis 5 reacts to the elastic-
ity of the flexible element 15, applying the moment of
force, which results from the distance between the ro-
tation axis and the tip of the boot, to the ski. A
CA 02685885 2009-11-02
WO 2008/139019 PCT/F12007/000127
12
kick. in classic skiing is thus applied downward,
pressing the central area of the ski to the ground and
resulting in a mechanical grip. The increased force
caused by the moment improves the ski grip and pro-
vides the grip to the kick at an earlier phase. In
skate style, the construction provides an advancing
kick, furthering the sliding of the ski for example on
the flat and during climbing. At the same time, the
increased contact surface area between the boot and
the binding provides a better control to different
phases of skiing in all horizontal and vertical direc-
tions.
Fig. 4 represents an embodiment of the inven-
tion in which the substantially free space under the
toe section of the ski boot is formed solely on the
soleplate 3 of the ski binding by shaping it to evenly
slope down and forward, from the axial locking 6 to
the coupling mechanism 4 of the binding. It this case,
the toe section and the ball section of the sole of
the boot are straight and parallel with each other.
Fig. 5 represents an embodiment of the inven-
tion in which the substantially free space under the
toe section of the ski boot is formed as in Fig. 4 on
the soleplate 3 of the ski binding by shaping it to
slope down and forward from the axial locking 6, but
here also the toe section of the sole of the boot is
shaped to slope slightly upward toward the tip of the
boot. However, the shape of the soleplate forms, in
this embodiment as well, the most significant space
for the movement of the tip of the boot.
Fig. 6 represents an embodiment of the inven-
tion in which the substantially free space 13 under
the toe section of the ski boot has a horizontal bot-
tom. In this case, the toe section of the sole of the
ski boot is straight and substantially parallel to the
other sections of the sole.
CA 02685885 2009-11-02
WO 2008/139019 PCT/F12007/000127
13
Fig. 7 represents an embodiment of the inven-
tion in which the substantially free space 21 is
formed on the ski 2. The wedge-shaped space 21 which
slopes down and forward on the ski, together with the
slight upward bending of the toe section of the sole
of the boot, form a space which opens and extends for-
ward from the coupling point of the sole of the boot,
in which space the tip of the boot, i.e. the toe sec-
tion, is able to bend during the kick phase when ski-
ing.. In this embodiment, the coupling mechanism 4 is
coupled to the ski and is part of the ski, so that the
axial locking at the back edge of the wedge-shaped
space 21 are connected to the coupling mechanism 4 via
the ski construction. Flexible elements of different
materials and different shapes can be used in this em-
bodiment as well to provide the desired bending prop-
erties to the boot.
Fig. 1 represents the embodiment in which the
wedge-shaped space is open and empty. In Fig. 3, the
wedge-shaped space is completely filled with the elas-
tic flexible element 15. In Fig. 4, the elastic flexi-
ble element 16 extends, as an evenly wide construc-
tion, laterally throughout the entire wedge-shaped
space 12, but along the length of the ski only to the
central area of the wedge-shaped space. In the embodi-
ment of Fig. 5, the flexible element 16 extends from
the tip of the wedge-shaped space 14, i.e. from the
rotation axis, approximately to the mid point of the
length of the wedge-shaped space along the length of
the ski. In the embodiment of Fig. 6, the flexible
element 16 is positioned in the center of the wedge-
shaped space 13 as in Fig. 4, but here the flexible
element tapers upwards so that the flexible properties
thereof can be adjusted as desired.
Figs. 8 and 9 represent measurement results
of a comparison between bindings in accordance with
the prior art and the binding in accordance with the
CA 02685885 2009-11-02
WO 2008/139019 PCT/F12007/000127
14 -
invention in skate style, Fig. 8, and in classic
style, Fig. 9. The curves indicate the force applied
to the grip zone of the ski during the kick phase,
i.e. when a grip is needed, as a function of time. The
lower curve, or the dark area, in the figures repre-
sents the traditional binding, and the upper curve
represents the solution in accordance with the inven-
tion.
As can be seen from Fig. 8, in free style
skiing, the force used for a kick, which lasts for
about one second, increases toward the end of the
kick. For the first half of the second, the forces are
nearly equal, but during the latter half of the kick,
the boot in the traditional binding begins to bend
just about its tip, so that it becomes difficult to
increase the force. However, in the binding in accor-
dance with the invention, the toe section bends in
front of and below the rotation axis during the final
phase of the kick, so that the kick force applied to
the ski increases significantly faster, becomes sig-
nificantly stronger and lasts significantly longer
than with traditional bindings.
According to Fig. 9, in classic skiing style
the kick forces applied to the ski are equal for only
about 1/3 of the total length of the kick. After this,
the flexible part in front of the boot in traditional
bindings unexpectedly causes, as the boot starts to
bend and the flexible part starts to compress, an in-
stantaneous decrease in the kick force, after which it
starts to rise again and reaches its maximum value at
about 0,7 seconds, descending steadily thereafter at
the end of the kick. The invention, however, does not
produce any kind of temporary decrease in the kick
force; instead the kick force increases relatively
linearly to reach the maximum level which is about 20%
greater than with the prior art, and descends rapidly
only after about 0,85 seconds.
CA 02685885 2009-11-02
WO 2008/139019 PCT/F12007/000127
The figures show clearly that with the bind-
ing construction in accordance with the invention, the
kick force is, at least for about half of the kick du-
ration, significantly greater, and for about 1/3 of
5 the kick duration at a higher level than the rela-
tively narrow peak that can be reached at the maximum
with the traditional binding. In addition, a relevant
and unexpected feature in the invention is that the
results described above can be obtained both in racing
10 and in relaxing recreational skiing, without any spe-
cific measures or any effort to learn anything, be-
cause the inventive binding construction and the func-
tioning thereof are based on the natural anatomy and
functioning of the foot.
15 The invention is not limited merely to the
examples of its embodiments referred to above; instead
many variations are possible within the scope defined
by the claims.
