U.S. patent application number 14/347880 was filed with the patent office on 2014-08-21 for device for protecting the knee joint that is able to engage with a ski boot.
The applicant listed for this patent is ET DES RESEAUX, IFSTTAR (INSTITUT FRAN AIS DES SCIENCE ET TECHNOLOGIES DES TRANSPORT, DE L'AMENAGEMENT, UNIVERSITE D'AIX-MARSEILLE. Invention is credited to Michel Behr, Pierre Gouniot.
Application Number | 20140230828 14/347880 |
Document ID | / |
Family ID | 47221482 |
Filed Date | 2014-08-21 |
United States Patent
Application |
20140230828 |
Kind Code |
A1 |
Gouniot; Pierre ; et
al. |
August 21, 2014 |
DEVICE FOR PROTECTING THE KNEE JOINT THAT IS ABLE TO ENGAGE WITH A
SKI BOOT
Abstract
A device for protecting the knee joint of a skier, the device
being for installing on a ski boot having a footwear portion
surmounted by a collar, the device having first connector designed
to be fastened to the collar of the boot and a shell designed to
cover the front of the tibia of the skier, the shell extending
between a high portion for being situated level with the skier's
knee and a low portion covering a portion of the collar of the
boot, the shell supporting, on its high portion, lateral flanges
suitable for being put into contact with the knee on either side of
the knee being in contact at least with the condyles of the femur
of the skier.
Inventors: |
Gouniot; Pierre; (Nice,
FR) ; Behr; Michel; (Marseille, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
IFSTTAR (INSTITUT FRAN AIS DES SCIENCE ET TECHNOLOGIES DES
TRANSPORT, DE L'AMENAGEMENT
UNIVERSITE D'AIX-MARSEILLE
ET DES RESEAUX |
Marseile Cedex 07
Champs-sur-marne |
|
FR
FR |
|
|
Family ID: |
47221482 |
Appl. No.: |
14/347880 |
Filed: |
October 25, 2012 |
PCT Filed: |
October 25, 2012 |
PCT NO: |
PCT/FR2012/052448 |
371 Date: |
March 27, 2014 |
Current U.S.
Class: |
128/846 |
Current CPC
Class: |
A63B 71/1225 20130101;
A63B 69/18 20130101; A61F 5/0123 20130101; A63B 2071/1258 20130101;
A63B 2071/125 20130101; A61F 2005/0181 20130101 |
Class at
Publication: |
128/846 |
International
Class: |
A63B 71/12 20060101
A63B071/12 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 4, 2011 |
FR |
1160020 |
Claims
1. A device for protecting the knee joint of a skier, the device
being for installing on a ski boot having a footwear portion
surmounted by a collar, the device having first connection means
designed to be fastened to the collar of the boot and a rigid shell
designed to cover the front of the tibia of the skier, at least in
part, the shell extending between a high portion for being situated
level with the skier's knee and a low portion covering a portion of
the collar of the boot, the shell including or supporting, on its
high portion, rigid lateral flanges suitable for being put into
contact with the knee on either side of the knee, being in contact
at least with the condyles of the femur of the skier, the low
portion of the shell being designed to cover part of the collar of
the boot and including second connection means complementary to the
first connection means of the collar of the boot and suitable for
securing the shell to and above the collar of the boot in such a
manner that the association of the first and second connection
means provides a connection with limitation of movement in rotation
of the shell relative to the boot about an axis of rotation
substantially parallel to the axis of the collar of the boot.
2. The device according to claim 1, characterized in that the
connection between the low portion of the shell and the collar of
the boot provided by associating the first and second connection
means provides a connection giving the shell at least one degree of
freedom to move in rotation relative to the boot about an axis
substantially parallel to the axis of the collar of the boot, the
connection means being such that this movement in rotation of the
shell relative to the boot is limited to a predetermined angular
sector of less than 14.degree..
3. The device according to claim 2, characterized in that the
flanges cover the sides of the knee completely, each flange
presenting a surface area of at least 50 cm.sup.2.
4. The device according to claim 1, characterized in that, in
horizontal section, the shell presents a forwardly bulging rounded
profile shape in such a manner as to cover the front of the knee
and of the tibia and it extends over a portion only of the sides of
the tibia, and in its low portion over a portion of the sides of
the collar.
5. The device according to claim 1, characterized in that the first
connection means comprise at least one guide part for installing in
stationary manner on the collar of the boot, said guide part being
suitable for co-operating with the second connection means of the
shell that are complementary to said guide part so as to limit
movement in rotation to the predetermined angular sector.
6. The device according to claim 1, characterized in that the
connection between the low portion of the shell and the collar of
the boot provided by associating the first and second connection
means prevents the shell from moving in rotation relative to the
boot about an axis substantially parallel to the axis of the collar
of the boot.
7. The device according to claim 1, characterized in that the first
and/or second connection means comprise at least one strap fastened
firstly to the collar of the boot, and secondly to the shell in
order to secure the shell to the collar of the boot.
8. The device according to claim 6, characterized in that said
first and second connection means include non-elastic straps
comprising two first straps fastened or suitable for being fastened
in releasable manner on either side to the rear of the collar, and
two second straps fastened or suitable for being fastened in
releasable manner on either side of the shell, said first and
second straps including complementary reversible connection means
at their free ends suitable for reversibly securing the free ends
of the first strap with the free ends of the second strap.
9. The device according to claim 1, characterized in that each of
the flanges presents an outline that is substantially in the form
of a portion of an ellipse over the top portion and over the rear
portion of said outline of the flange, the major axis of the
ellipse being inclined at an angle lying in the range 45.degree. to
135.degree. relative to the main longitudinal axis of the shell
parallel to the rectilinear section of the front face of the shell
in section on a longitudinal midplane.
10. The device according to claim 9, characterized in that said
major axis of the ellipse is inclined at an angle lying in the
range 70.degree. to 110.degree. relative to said main longitudinal
axis of the shell, and the surface of the flange corresponds
substantially to the top lateral portion of the shell situated
above the bottom tangent of the ellipse parallel to the major axis
of the ellipse and behind an axis parallel to the minor axis of the
ellipse situated about halfway along the major radius of the
ellipse starting from the rectilinear section of the front face of
the shell in a longitudinal midplane of the shell.
11. The device according to claim 1, characterized in that the
shell supports at least one element for connection to the tibia in
its high portion, comprising a strap.
12. The device according to claim 1, characterized in that the
contact of the lateral flanges against the condyles of the femur
takes place via ergonomic spacers inserted against the inside faces
of the flanges.
13. The device according to claim 1, characterized in that the
flanges cooperate with or include said spacers that in part match
the shape of the morphology of the sides of the knee without
hindering frontal flexions of the knee.
14. The device according to claim 1, characterized in that said
flanges and/or spacers include linings of flexible material for
coming into contact with the knee of the skier.
15. The device according to claim 14, characterized in that each of
said spacers comprises a rigid support covered on its knee side
with a lining of flexible material for coming into contact with the
knee of the skier.
16. The device according to claim 3, wherein the surface area is at
least 100 cm.sup.2.
17. The device according to claim 10, wherein the angle is
90.degree..
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to the general field of
devices for protecting the knee joint and suitable for co-operating
with a ski boot, where such a boot conventionally comprises a
footwear portion surmounted by a collar.
[0002] Such a device is for use by a competitive and/or
recreational skier. Nowadays, every year in France, there are about
17,000 knee sprains with or without broken ligaments as a result of
falls while skiing. This gives rise to treatments that are lengthy
and to side effects that are often major. Direct and indirect costs
for society are very considerable, being evaluated at 300 million
euros (M) per year.
[0003] It is known that the knee can withstand relatively high
stress so long as it is of very short duration. In contrast,
lesions can appear in the ligaments at low levels of force if the
stress is maintained for a duration that is long enough.
[0004] Devices for protecting the knee joint seek to reduce the
risk of tearing a ligament in a skier's knee. Proper operation of
such devices requires them to protect the joint while it is being
very highly stressed, while also allowing freedom of movements
during normal skiing.
[0005] In general, the only safety element in existence for
protecting a skier's knee is the ski binding. The principle
consists in releasing the boot when the jaws of the binding are
subjected to torque exceeding a certain trigger threshold.
[0006] In practice, that situation leads to two main problems: a
competitive or an experienced skier will tend to set the trigger
threshold of the bindings very high. This avoids untimely
triggering when edging hard. In contrast, falling is much more
dangerous since the bindings will have greater difficulty in
releasing the boot.
[0007] A beginner skier might end up falling very slowly. The
trigger threshold is then never reached, even if it is set low
enough.
[0008] The invention seeks to limit the risks of knee injuries in
particular sprains and torn ligaments associated with excessive
relative axial rotation of the tibia or femur and/or excessive
shear in the X'Y' plane.
[0009] Movements in rotation and in translation between the tibia
and the femur are measured relative to three axes at the knee. For
this purpose, if a local frame of reference is defined tied to the
top end of the tibia: the substantially horizontal X'Y' plane is
the plane of the tibial plateau; with the axis Z' being the
longitudinal axis of the tibia perpendicular to the plane of the
tibial plateau, and thus substantially vertical.
[0010] In this frame of reference, the following movements in
rotation and in translation can take place as shown in FIG. 11:
[0011] axial rotation of the tibia at the knee: this rotation
corresponds to the angle between two transverse vectors of the
tibia and of the femur, one at the tibial plateau and the other
between the two condyles of the femur, this rotation being
projected onto the tibial plateau (plane X'Y') (FIG. 11A); [0012]
rotation in lateral flexing: this corresponds to the angle between
the two transverse vectors of the tibia and the femur, but in the
Y'Z' plane, also referred to as valgus-varus (FIG. 11C); [0013]
rotation in frontal flexing: this rotation corresponds to the angle
between two longitudinal vectors of the tibia and of the femur in
the X'Z' plane (FIG. 11B); [0014] shear of the knee corresponding
to movement in translation between the tibia and the femur along
the three axes X, Y, and Z, and in particular shear towards the
front of the femur along the axis X'; and [0015] internal or
external axial rotation of the tibia at the knee when the foot and
the ankle are held in a ski boot gives rise to internal or external
rotary movement through a given angle relative to the horizontal
longitudinal axis Y of the foot, of the boot, and of the ski (FIG.
12).
[0016] The natural mobility of the knee depends on its frontal
flexing angle in the X'Z' plane (FIG. 11B) in axial rotation about
Z'. Although the knee does not allow the tibia to rotate axially
relative to the femur while the knee is in full extension, the
amplitude of the external or internal axial rotation of the tibia
that is allowed by the knee increases with increasing frontal
flexing angle. Thus, with a frontal flexion angle of 90.degree.,
the internal axial rotation of the tibia is about 30.degree.,
correspondingly bringing the toe inwards, in combination with the
adduction or abduction movement of the foot. The external axial
rotation of the tibia is about 40.degree. in external rotation.
Although the locking of the ankle by the ski boot limits very
strongly this amplitude of axial rotation of the tibia, it can
still reach 20.degree. in internal rotation and 25.degree. in
external rotation, giving a total amplitude of 45.degree..
[0017] The invention seeks to provide a protection device that does
not impede the skier under normal skiing conditions, in particular
during frontal flexing of the knee.
[0018] Various documents including U.S. Pat. No. 4,136,404, GB 2
436 799, or U.S. Pat. No. 6,524,110 describe systems for attaching
to the boot. Those systems run along the lower limb, generally on
either side, and they serve to stiffen the knee joint laterally.
For that purpose, in all of those documents, a rigid top portion is
hinged on a likewise rigid bottom portion, with the hinge being
level with the knee. Those devices have generally not given rise to
any use, or they have given rise to very restricted use with very
particular sectors of the public, in particular with people
suffering from certain kinds of minor disability.
[0019] In FR 2 679 931, GB 2 436 799, and WO 2009/092452, devices
are described for fastening around the thigh, the tibia, and/or the
knee and to the boot. Those devices have pivot connection type
hinge systems at the knee since they seek to accompany frontal
flexing of the femur relative to the tibia in the (substantially
vertical) sagittal plane. However those devices do not prevent
axial rotations of the femur and the tibia; at best they slow down
axial rotations without controlling them and without preventing
them.
[0020] Furthermore, in FR 2 679 931 and WO 2009/092452, the devices
co-operate with a boot by means of pads that are inserted inside
the collar.
[0021] Those devices are also complex to fabricate and awkward to
install on the lower limb. Insofar as those devices include a hinge
that is to be aligned with the skier's knee joint, they also need
to be made to measure. It is thus observed that those products are
not commercially available and are not used by competitors.
[0022] It should also be observed that the tibia can be fractured
instead of spraining the knee or at the same time as spraining the
knee. Excessive twisting or flexing of the leg while the foot and
ankle are practically locked in the ski boot contributes to
providing conditions that lead to a fracture of the tibia.
[0023] The object of the present invention is to provide a simpler
device seeking essentially or mainly to limit shear in the plane of
the tibia, in particular forward shear of the femur along the axis
X', and also seeking to limit relative axial rotations of the femur
and tibia, but without interfering with frontal flexing at the knee
and in particular without having recourse to a pivot connection at
the knee and/or thus without having recourse to a device that needs
to be connected to the thigh.
OBJECT AND SUMMARY OF THE INVENTION
[0024] A main object of the present invention is thus to limit the
risk of injury to the ligaments and/or bones as a result of shear,
in particular of forward shear of the femur along the axis X', and
as a result of relative axial or lateral rotation of the tibia or
the femur while skiing, by means of a device that is simple and
fabricate and to put on the lower limb, and that can be useful to a
skier regardless of the pair of skis being used.
[0025] In the present invention, the device essentially comprises
no more than a rigid shell provided with lateral flanges in its
upper portion without any connection with the thigh and with means
for connecting the shell to the collar so as to enable controlled
limitation of rotation of the shell relative to the collar about
the Z axis.
[0026] To do this, invention provides a device for protecting the
knee joint of a skier, the device being for installing on a ski
boot having a footwear portion surmounted by a collar, the device
having first connection means designed to be fastened to the collar
of the boot and a rigid shell designed to cover the front of the
tibia of the skier, at least in part, the shell extending between a
high portion for being situated level with knee and a low portion
covering a portion of the collar of the boot, the shell including
or supporting, on its high portion, rigid lateral flanges suitable
for being put into contact with the knee on either side of the
knee, being in contact at least with the condyles of the femur, the
low portion of the shell being designed to cover part of the collar
of the boot and including second connection means complementary to
the first connection means of the collar of the boot and suitable
for securing the shell to and above the collar of the boot in such
a manner that the association of the first and second connection
means provides a connection with limitation of movement in rotation
of the shell relative to the boot about an axis of rotation
substantially parallel to the axis of the collar of the boot.
[0027] With fabrication that is particularly simple, the invention
makes it possible to limit the risk of injury associated with shear
in the tibial plane, in particular shear and axial or lateral
movements in rotation of the tibia or femur.
[0028] More particularly, the flanges completely cover the sides of
the knee and the contact surfaces of the flanges, which press
internally against the sides of the knee, cover at least the
lateral surfaces of the knee that are in register with the femoral
condyles.
[0029] More particularly, in horizontal section, the shell presents
a forwardly bulging rounded profile shape (i.e. face convex towards
the front) in such a manner as to cover the front of the knee and
of the tibia and it extends over a portion only of the sides of the
tibia, and in its low portion, over a portion of the sides of the
collar. In practice, the shell may extend over a height of 30
centimeters (cm) to 55 cm, depending on the size of the skier.
[0030] The essential main function of the rigid shell is to support
the flanges and to transfer the thrust forces of the knee against
the flanges down to the boot and thus down to the binding holding
the boot on the ski, since it is the bonding that determines the
acceptable level of force, with the binding releasing the boot
beyond a certain threshold.
[0031] The secondary function of the shell is to protect the front
of the tibia against possible impacts.
[0032] The surfaces of the flanges thus perform an essential role
because the transfer of force is maximized when the sides of the
knee are pressing against the flanges if the thrust surface of the
flange against the side of the knee is optimized.
[0033] Consequently, the thigh is held relative to the boot by
using simple flanges that press against the condyles of the femur
in association with a rigid tibia-protecting shell that is limited
in the movements it can perform relative to the ski boot. This
limitation very greatly reduces any risk of pathological movements
in axial or lateral rotation between the tibia and the femur at the
knee, and/or limits risks of shear, in particular forward shear of
the femur along the axis X'.
[0034] It can be understood that said means for connecting the
shell to the collar can allow the shell small degrees of freedom to
move in rotation relative to the collar about an axis of rotation
parallel to the longitudinal axis X of the ski and about an axis of
rotation parallel to the transverse axis Y perpendicular to the
longitudinal direction X of the ski, so as to avoid preventing and
so as to track any frontal and lateral flexion movements of the
tibia relative to the ankle in the boot and any frontal
hyper-flexion movements of the leg rewards, it nevertheless being
specified that the degree of freedom in rotation about the axis X
for forward frontal movement of the shell is limited by the
connection, if any, between the high portion of the shell and the
tibia, as described below, and the degree of freedom in rotation
about the axis X is limited by the overlap and the contact between
the shell and the lateral sides of the collar.
[0035] According to an advantageous characteristic, the connection
between the low portion of the shell and the collar of the boot
provided by associating the first and second connection means
provides a connection giving the shell at least one degree of
freedom to move in rotation relative to the boot about an axis
substantially parallel to the axis of the collar of the boot, the
connection means being such that this movement in rotation of the
shell relative to the boot is limited to a predetermined angular
sector, preferably of less than 14.degree..
[0036] With this characteristic, the connection means provide a
connection with at least one degree of freedom to move in rotation
about an axis parallel to the axis of the tibia. The skier thus
conserves a satisfactory amplitude of movement for skiing.
[0037] In contrast, axial movements in rotation between the tibia
and the femur and also forward shear of the femur are limited by
the presence of the shell.
[0038] According to a preferred characteristic, the device has
means for adjusting the predetermined angular sector over which
such movement in rotation is limited.
[0039] Connecting the device above the collar in accordance with
the present invention presents the following advantages: [0040] it
does not interfere with the necessary small natural freedom to move
of the tibia inside the collar; [0041] it enables the connection to
be adjusted easily, in particular concerning the amplitude of
rotation about the axis of the collar, thus making it easy to
control the limit on movement in rotation about the axis Z of the
device relative to the collar; and [0042] it makes it possible to
optimize the transfer of forces applied against the device down to
the binding of the boot on the ski.
[0043] This characteristic enables the skier to adapt the limit on
rotation provided by the device to the skier's manner of skiing.
This makes it possible to adjust the threshold beyond which axial
rotation is blocked or at least braked by the device.
[0044] According to a particular characteristic of the invention,
the device is such that the predetermined angular sector of
rotation of the shell relative to the collar about an axis parallel
to the Z axis of the collar is less than 14.degree., preferably
less than 10.degree., and more preferably less than 7.degree..
Thus, the amplitude of axial rotation between the tibia and the
femur is limited respectively to less than 45.degree.,
advantageously to less than 30.degree., and preferably to less than
14.degree..
[0045] An angular sector in the range 45.degree. to 30.degree.
serves to limit the risks of knee sprains in certain flexing
positions while preserving good skiability. An angular sector in
the range 30.degree. to 14.degree. makes it possible to obtain a
wider spectrum of knee protection with minor detriment to the level
of skiability. Such angular limitation makes it possible in
particular to avoid reaching the breaking limit of the tibia. This
provides increased protection for the tibia and for the knee joint,
while leaving appreciable latitude of movement in certain skiing
situations.
[0046] An angular limitation of 14.degree. corresponds on average
to the acceptable angular amplitude between the tibia and the
femur. Knee protection is then optimized, since it is ensured that
this limit is not reached whatever the behavior of the tibia. In
general, it should be observed that the foot/ankle/tibia unit in a
ski boot is constrained in such a manner that adduction and
abduction are very limited. Movement of the foot relative to the
tibia is thus very limited. In the event of an impact, the skier
thus cannot benefit from this angular margin.
[0047] Furthermore, as a general rule, since the breaking limit of
the femur is well above the limit for knee sprain, the risk of
breaking the femur is small. In the event of this breaking limit of
the femur being approached during an impact, the device of the
invention may include a mechanical fuse so as to transfer the load
to the knee even at the risk of that leading to a sprain.
[0048] In each of its embodiments, the device of the invention
prevents, or under the worst circumstances brakes, movement of the
thigh in rotation relative to the boot, i.e. the angle of the
longitudinal axis of the femur relative to the axis of the ski.
[0049] This provides a significant limit on the risk of damage to
the ligaments and/or the bones, which is achieved by the presence
of the lateral flanges in contact with the condyles and by the
limited movement of the shell relative to the boot, with this
limitation being adapted as a function of the maximum angular
amplitude allowed by the knee and as a function of the skiability
preferences of the user.
[0050] In an advantageous embodiment of the invention, the first
connection means comprise at least one guide part for installing in
stationary manner on the collar of the boot, said guide part being
suitable for co-operating with the second connection means of the
shell that are complementary to said guide part so as to limit
movement in rotation to the predetermined angular sector.
[0051] This embodiment involves installing at least one particular
element on each boot for enabling the shell connection means to
operate, and it makes it possible to achieve accurate control over
the behavior of the shell relative to the boot. It is envisaged
herein that these first connection means installed on the boot are
elements that are present on the boot by default, such as a
fastener or other element relative to which the shell takes up its
position in order to have its movement in rotation limited.
[0052] With this characteristic, it should be observed that it is
only ski boots that need to be provided beforehand with connection
means in order to make use of the complementary connection means of
the shell, without there being any need to modify the pair of skis
in any way. Furthermore, a single shell can perfectly well be used
by a given skier with any one of a plurality of pairs of boots,
providing they are fitted with at least one guide part of this
embodiment.
[0053] In a particular embodiment, the guide part comprises at
least one rail for fastening to the collar of the boot so as to be
substantially parallel to the axis of the boot, the second
connection means constituting a groove that is complementary to the
rail, the groove presenting a width that is greater than the width
of the rail, thus allowing limited rotation about the axis that is
substantially parallel to the collar of the boot.
[0054] Providing the groove is wider than the rail, the use of such
a guide part forming the rail along the axis of the collar of the
boot and co-operating with a groove carried by the connection means
of the shell makes it possible for them to be relatively movable in
rotation over an angle that is limited, and specifically over an
angular sector of less than 14.degree., or advantageously less than
10.degree., or preferably less than 5.degree..
[0055] The width of the groove and the width of the rail are then
determined as a function of the degree to which it is desired to
limit rotation of the shell on the collar of the boot.
[0056] In another embodiment, the guide part has at least one
groove for fastening on a lateral flank of the collar of the boot
so as to be substantially parallel to the axis of the collar, the
second connection means constituting a rail complementary to the
groove, the groove presenting a width that is greater than the
width of the rail, this width allowing limited rotation about the
axis that is substantially parallel to the collar of the boot.
[0057] In this embodiment, it is the collar of the boot that
carries the groove and the shell that carries a rail that can be
allowed to move in the groove by the groove being wider than the
rail.
[0058] In a particular characteristic, the difference between the
width of the groove and the width of the rail varies along those
structures, with this variable difference in width governing a
front/rear flexing angle between the shell and the boot.
[0059] A variable difference in width between the two structures,
the groove and the rail, serves to determine a front/rear flexing
angle between the shell and the boot. When the high path of the
groove is wider than the low path of the grove, while the rail is
of constant width, then the shell can tilt forwards in free
manner.
[0060] In another embodiment, the width of the groove and the width
of the rail are constant, and the length of the rail is determined
so as to determine a front/rear flexing angle between the shell and
the boot. This embodiment enables the groove to pivot about the
rail. The rail then acts as a pivot within the groove, which pivots
about the rail.
[0061] In a second embodiment of the invention, the first and/or
second connection means comprise at least one strap fastened
firstly to the collar of the boot, and secondly to the shell in
order to secure the shell to the collar of the boot.
[0062] This embodiment makes use either of the elasticity of the
strap adapted as a function of the desired limitation on movement
in rotation, or on a particular adjustment of the clamping of the
strap which should then be inextensible, so as to allow a limited
amount of movement in rotation of the shell relative to the boot.
Such a particular adjustment of the clamping of the strap allowing
a limited amount of movement in rotation over a predetermined
angular sector is achieved by means of a mechanical element
enabling the strap to be lengthened or shortened or enabling a
predetermined length of the strap to be maintained. This type of
device makes it easier to establish the connection between the
shell and the collar.
[0063] Advantageously, the strap presents a particular length or a
particular marking for adjustment purposes. For the guide part, the
limitation is obtained by adjusting the width of the rail, whereas
when a strap is used, the limitation is obtained by the ability of
the strap to be extended, either because it is initially slack or
because it is elastic.
[0064] Either the strap is suitable for limiting movement in
rotation in both directions, or else the strap is associated with
an abutment, or indeed two straps are used. Thus, in a particular
embodiment, the first and second connection means comprise two
straps, each of which has one end fastened to the collar and the
other end to the shell, with the extent to which the straps can be
extended limiting rotation in each of two opposite directions of
rotation.
[0065] The use of two straps makes it possible to adjust the
movement in rotation of the shell in both directions of rotation
and thus to limit this movement in both directions of rotation.
[0066] In a variant embodiment, the connection between the low
portion of the shell and the collar of the boot provided by
associating the first and second connection means prevents the
shell from moving in rotation relative to the boot about an axis
substantially parallel to the axis of the collar of the boot.
[0067] Under such circumstances, and more particularly, said first
and second connection means include non-elastic straps comprising
two first straps fastened or suitable for being fastened in
releasable manner on either side to the rear of the collar, and two
second straps fastened or suitable for being fastened in releasable
manner on either side of the shell, said first and second straps
including complementary reversible connection means at their free
ends suitable for reversibly securing the free ends of the first
strap with the free ends of the second strap.
[0068] In a particular embodiment, the device also includes at
least one abutment part for fastening to the collar of the boot,
the shell also including a collar abutment element complementary to
the abutment part of the collar and suitable for co-operating
therewith in order to position the shell vertically along the
tibia.
[0069] The abutment part serves to control proper vertical
positioning of the shell relative to the tibia, and thus relative
to the lower limb, in general manner.
[0070] In an embodiment, with the device in position at rest on the
lower limb, the flanges apply force against the condyles
substantially normally relative to the flanks of the thigh with a
magnitude lying in the range ]0, 100 newtons (N)].
[0071] It is advantageous for the flanges to exert a non-zero force
on the condyles of the femur so that any movement of the condyles
relative to the flanges of the shell is minimized. Under such
circumstances, only the degree of freedom to move in rotation about
the axis Z is made available by the connection means connecting the
shell to the collar of the boot and by the deformability of the
material of the shell and the deformability of the soft
tissues.
[0072] In the invention, in its broadest definition, the flange
presents an outline over its rear portion and its top portion that
is of arbitrary shape and the flange is of a size that is
sufficient to cover the surface of the condyles of the femur.
[0073] More particularly, each flange presents a surface area
suitable for covering the total surface area of the sides of the
knee, preferably an area of at least 50 square centimeters
(cm.sup.2), and preferably of at least 100 cm.sup.2.
[0074] In a preferred embodiment, the flanges present an outline
that is substantially in the form of a portion of an ellipse, in
particular in the top and rear portions of the flanges. More
particularly, the flanges present an outline that is substantially
in the shape of at least half an ellipse over its top portion and
over its rear portion.
[0075] Still more precisely, the major axis of the ellipse is
inclined at an angle lying in the range 45.degree. to 135.degree.
relative to the main longitudinal axis of the shell parallel to the
rectilinear section of the front face of the shell in section on a
longitudinal midplane of the shell.
[0076] Also preferably, the major axis of the portion of an ellipse
is inclined at an angle lying in the range 70.degree. to
110.degree. and preferably equal to about 90.degree. relative to
said main longitudinal axis of the shell.
[0077] The preferred use of flanges having an elliptical outline is
particularly suitable for providing lateral support to the lateral
flanks of the thigh, with the orientation of the flanges enabling
the skier's femur to be supported correctly in the skiing position
without hindering the skier.
[0078] More particularly, the surface of each flange corresponds
substantially to the surface of the top lateral portion of the
shell situated above the bottom tangent of the ellipse parallel to
the major axis of the ellipse and behind an axis parallel to the
minor axis of the ellipse (and thus perpendicular to the major axis
of the ellipse) situated about halfway along the major radius of
the ellipse starting from the rectilinear section of the front face
of the shell in a longitudinal midplane of the shell.
[0079] More particularly, the center of the ellipse is located
substantially facing the condyle to within .+-.20 millimeters (mm)
depending on the flexing at the knee. The bottom tangent to the
ellipse parallel to the major axis of the ellipse is situated
substantially facing the tibial plane when the major axis of the
ellipse is at substantially 90.degree. to said longitudinal axis of
the shell parallel to the rectilinear section of the front face of
the shell in section on a longitudinal midplane of the shell.
[0080] Still more particularly, the major axis of the ellipse is at
least 5 cm long, and preferably of a length lying in the range 6 cm
to 15 cm, and the minor radius of the ellipse is at least 2 cm
long, and more particularly lies in the range 3 cm to 10 cm.
[0081] Still more particularly, the major axis of the ellipse is
situated at 2 cm to 5 cm from the top end of the shell, and the
center of the ellipse is situated at 5 cm to 10 cm from the
rectilinear section of the front face of the shell in section on a
longitudinal midplane of the shell.
[0082] Such dimensions for the ellipse and such an angle of
inclination for the major axis of the ellipse lying in the range
70.degree. to 110.degree. enable the relationship between the
flanges and the end of the bottom femoral epiphysis to be
maintained in spite of the movement of the condyles during
flexion/extension movements of the knee. This angle of inclination
also corresponds to an intermediate angle of inclination between
the positions of the thigh in movement or at rest.
[0083] More particularly, the flanges present surface areas
suitable for covering the entire surface area of both sides of the
knees, each flange preferably having an area of at least 50
cm.sup.2, and more preferably of at least 100 cm.sup.2.
[0084] Such a size for the flanges makes it possible to ensure good
coverage of the femoral epiphysis, while ensuring that the device
of the invention does not hinder the skier.
[0085] Also advantageously, the shell supports at least one element
for connection to the tibia in its high portion, in particular a
third strap having a self-gripping tape for holding it around the
tibia.
[0086] Such a characteristic is the simplest way of holding the
shell relative to the skier's tibia, other than securing it to the
boot. It presents the advantage of being easy to implement and
simple for the skier to handle.
[0087] In a preferred embodiment, the contact of the lateral
flanges against the condyles of the femur takes place via ergonomic
spacers inserted against the inside faces of the flanges. More
particularly, the device has flanges that cooperate with or that
include ergonomic spacers against the inside spaces of the flanges.
This characteristic makes it possible to adapt a common shell to
condyles having a variety of dimensions by interposing a variety of
spacers. A common molded shell can thus be used for different sizes
of device and also for making devices that are personalized. Under
such circumstances, only the spacers need to be modified in order
to obtain a variety of sizes or in order to obtain a personalized
device.
[0088] The inside surfaces of the spacers may be made to measure so
as to match the shape of the lower limb of a particular skier
without hindering the flexion/extension movements of the knee.
[0089] Preferably, the flanges include ergonomic spacers on their
inside surfaces that match in part the shape of the morphology of
the sides of the knee without hindering frontal flexing of the
knee. The area defined by the outline of a spacer thus corresponds
to the area defined by the outline of the flange as described above
and thus presents a value of at least 50 cm.sup.2, and preferably
of least 100 cm.sup.2.
[0090] Advantageously, these ergonomic spacers may present a
surface that is the result of melding the surfaces observed at the
condyles of the skier for at least two preferred angular positions
of the skier's lower limbs.
[0091] This personalization characteristic enables the device to be
particularly agreeable to use in all skiing positions. Furthermore,
this personalization of the protection device of the invention is
most advantageous insofar as it serves to provide a very secure
connection between the lateral flanges and the knee. This avoids
any penalizing clearance being present at this point of the device,
where such clearance would involve the femur being free to turn
through an angle relative to the boot that is greater than the
maximum angle determined by the device of the invention.
[0092] Advantageously, said flanges and/or spacers include linings
of flexible material for coming into contact with the sides of the
knee of the skier (S).
[0093] Still more particularly, each of said spacers comprises a
rigid support covered in a lining of flexible material for coming
into contact with the skier's knee, i.e. the portion that is to
press against a side of the knee. The linings are arranged on the
inside faces of the flanges, or preferably on the inside faces of
the spacers, when spacers are used.
[0094] This characteristic increases skier comfort without
degrading the effectiveness of the invention in terms of lateral
movements in rotation.
[0095] More particularly, each of said spacers comprises a rigid
support covered on its knee side with a lining of flexible material
for coming into contact with the knee of the skier.
[0096] The lining may be made of a flexible material of the
cellular material type (foam etc.), or of the gel type (silicone,
etc.). The lining is thus advantageously made from at least one
elastomer or plastics material of the ethylene vinyl acetate (EVA)
type or of some other type that is optionally thermoformable and
that presents thickness and density that are sufficient to provide
comfort during movement of the lower limb while skiing. More
particularly, the material may be a silicone gel in the form of a
plate having thickness lying in the range 1 mm to 10 mm, and
preferably in the range 2 mm to 5 mm.
[0097] The shell and the spacers are advantageously made of a rigid
material that may be inorganic or organic, and it may be in a
single piece or it may be in composite form, using materials
selected from the following: magnesium, aluminum, titanium, metal
alloys, polymers that may optionally be filled and that may
optionally be reinforced, and resins that may optionally be
composite, that may optionally be filled, and that may optionally
be reinforced.
[0098] Advantageously, the composite is constituted by a matrix
based on a thermosetting type resin such as epoxy, polyester, etc.,
or on a thermoplastic resin of the polyamide (PA) type or of the
polycarbonate (PC) type or of some other type, together with at
least one reinforcing material. The reinforcing material may be
based on carbon fibers and/or on glass fibers and/or aramid fibers,
e.g. on Kevlar.RTM. (trademark of the supplier of Dupont de
Nemours) and/or on poly p-phenylene-2.6-benzobisoxazole (PBO)*
(trademark of the supplier Toyobo Japan), and/or on PIPD M5 from
the supplier Dupont de Nemours, and/or on ultra high molecular
weight polyethylene (UHMWPE) DYNEEMA (trademark of the supplier DSM
Holland). The reinforcing content in the composite lies in the
range 0% to 70%. The reinforcement may be woven or knitted or
braided, and it may be of the two-dimensional, or
three-dimensional, or uni-dimensional type, or it may be
constituted by cut fibers. Organic or inorganic fillers may be
added to the matrix depending on the desired specifications. It is
possible for the polymer material of the matrix and for the
reinforcing fibers to contain carbon nanotubes in order to improve
their mechanical characteristics. These materials generally serve
to provide the shell and the spacers with good stiffness while also
being light in weight and comfortable.
[0099] At least on a face of the lining that comes into contact
with the lower limb, it is possible to apply a film or a fabric of
the spandex or elastic type having a thickness of at least 10
micrometers (.mu.m), the film or fabric being attached by adhesive
to said surface in order to match the shape of the spacer.
[0100] The material of the film or fabric may present a low
coefficient of friction. By way of example, the material may be
made from polytetrafluoroethylene (PTFE) (e.g. of trademark Teflon
in the name of Dupont de Nemours, USA). The thickness of the film
or of the fabric is selected depending on the desired mechanical
characteristics.
[0101] When the flanges or the spacers include a flexible lining
over the portion that is to press against the sides of the knee,
said connection means need not authorize any degree of freedom of
the shell to move relative to the boot about an axis Z
substantially parallel to the axis of the collar of the boot, since
the condyles of the femur are held by the spacers positioned in the
flanges and the spacers allow for a small amount of relative axial
movement in rotation between the femurs and the tibias because the
soft tissues between the condyles and the spacers deform when
performing a movement in rotation. The angular sector is thus
limited sufficiently by the shape and the clearance of the spacer
in contact with the soft tissue over the condyles of the femur.
[0102] In general, the capacity of the device for adjustment and
adaptation by using spacers enables the device to be adapted to the
variability of skiers: age, sex, physical condition, muscle tone,
contraction levels, etc. . . . . The expected levels of stress
conditions are also corresponding parameters for adjusting the
device: shear, lateral section, speeds, skier position, vertical
acceleration, prestress between the device and the knee, etc.
BRIEF DESCRIPTION OF THE DRAWINGS
[0103] Other characteristics and advantages of the present
invention appear from the following description made with reference
to the accompanying drawings which show an embodiment having no
limiting character. In the figures:
[0104] FIG. 1 shows the principle of the invention;
[0105] FIGS. 2A to 2E show a first embodiment of the invention;
[0106] FIGS. 3A to 3E show a second embodiment of the
invention;
[0107] FIGS. 4A to 4E show a third embodiment of the invention;
[0108] FIGS. 5A to 5C are diagrams showing the principle of a
fourth embodiment of the invention;
[0109] FIGS. 6A and 6B show a preferred embodiment of the
invention;
[0110] FIGS. 7A to 7C show spacers as used in the preferred
embodiment of the invention;
[0111] FIG. 8 shows a device of the invention provided with spacers
in the preferred embodiment of the invention;
[0112] FIGS. 9A and 9B are perspective views of a preferred
embodiment without a boot (FIG. 9A) and fastened on a boot (FIG.
9B);
[0113] FIG. 10 shows a shell fitted with non-elastic straps;
[0114] FIGS. 11A to 11C show rotations between the femur and the
tibia, axial rotation about the axis of rotation Z' (FIG. 11A),
frontal rotation about Y' (FIG. 11B), and lateral rotation about X'
(FIG. 11C);
[0115] FIG. 12 shows the XYZ frame of reference relative to a boot;
and
[0116] FIG. 13 shows variations in the angle of the femur relative
to the longitudinal axis of the ski resulting from axial rotation
of the tibia with and without the device of the invention, thereby
showing the effectiveness of the invention.
DETAILED DESCRIPTION OF AN EMBODIMENT
[0117] FIG. 1 is a diagram of the invention. This figure shows the
bottom of the body of a skier S. The skier S has a ski boot 2,
which is fastened to a ski 1 by means of a binding 1a. The boot 2
has a footwear portion and a collar 21.
[0118] In FIG. 1, the foot P, the tibia T, and the femur F of the
skier S can be seen. The femur F has condyles CF at its distal end.
These condyles CF occupy a plurality of intermediate positions
between two extreme positions that are shown in FIG. 1, as a
function of the flexion position of the skier S.
[0119] In FIG. 1, the skier S is wearing a device of the invention.
The device comprises a rigid shell 10 with a high portion 11 and a
low portion 12. The low portion 12 has connection means for
securing the shell 10 to the collar 21 of the boot 2. The high
portion of the shell 10 has two lateral flanges that cover the
condyles CF of the femur F on either side of the leg of the skier
S, with this covering being provided by the lateral flanges in any
flexion position of the skier S.
[0120] The lateral flanges present an outline 11c forming a portion
of an ellipse with a major axis X1 being oriented at about
70.degree. relative to Z'. This orientation lies in the range
45.degree. to 135.degree. and serves to obtain satisfactory
pressure on the condyles of the femur and thus good retention of
the femur for axial and lateral rotations relative to the tibia.
The embodiments described below show preferred orientations for the
lateral flanges lying in the range 70.degree. (FIG. 1) to
90.degree. (FIG. 10).
[0121] In FIG. 10, the height H of the shell lies in the range 300
mm to 600 mm, and more particularly in the range 350 mm to 500 mm,
depending on the size of the skier.
[0122] In FIG. 10, the outline 11c of the top and rear portions of
the flange presents a shape including substantially an upper
half-ellipse and a lateral half-ellipse forming parts of the same
virtual ellipse of center C1 that is substantially in register with
the condyle CF. The major axis X1 of the ellipse is substantially
perpendicular to the longitudinal main axis of the shell and
perpendicular to the rectilinear section of the front face limit
10a of the shell in a section on a longitudinal midplane of the
shell. Each flange is defined by a bottom tangent X2 of said
ellipse that is substantially in register with the tibial plane
X'Y' parallel to the major axis X1 of the ellipse. The major radius
R of the ellipse is 65 mm and the minor radius r of the ellipse is
50 mm. The center C1 of the ellipse is situated at a distance d=68
mm from the front face limit 10a of the shell in a section on the
longitudinal midplane of the shell. The total area of each flange
11a, 11b as defined by the surface situated above the bottom
tangent line X2 to the ellipse that is parallel to X1 and behind an
axis Z2 parallel to the minor axis Z1 of the ellipse is situated at
about 1/2 R from the rectilinear section of the front face 10a of
the shell in section on the longitudinal midplane of the shell, and
said surface area is about 100 cm.sup.2.
[0123] Thus, the lateral flanges completely cover the distal
femoral epiphysis, each bearing on opposite sides of the end of the
femur, i.e. against the femur condyles CF on either side of the
knee. They serve to limit lateral rotation of the femur F relative
to the foot P of the skier S.
[0124] Advantageously, the force with which the flanges press
against the condyles is adjustable. The flanges apply a force on
the condyles substantially normal to the flanks of the thigh with a
magnitude lying in the range ]0, 100N].
[0125] FIGS. 2A and 2E show a first embodiment of the invention.
These figures are respectively a face view of the device 10, a side
view, a plan view, and after being put into place on a ski boot, a
side view and a perspective view.
[0126] The device 10 has two lateral flanges 11a and 11b for
placing on either side of the skier's knee so as to clamp onto the
femur condyles CF. The lateral flanges 11a and 11b may themselves
be in contact with the garment covering the condyles CF or it may
be in contact with the condyles CF via spacers, as described
below.
[0127] The bottom portion 12 of the device 11 has second connection
means 12a and 12b. The second connection means 12a and 12b of the
shell are complementary to the first connection means referenced
22a and 22b, forming guide parts on the collar 21 of the boot 2.
Such first connection means 22a and 22b are shown in FIGS. 2D and
2E.
[0128] In the embodiment shown in FIGS. 2B-2E, the first connection
means 22a and 22b constitute a guide part made up of two elements
referenced M1 and M2 and forming jaws. The second connection means
12a and 12b are constituted by two tongues referenced La and Lb,
each sliding between the two pairs of jaws M1 and M2 placed on
either side of the collar 21 of the boot 2.
[0129] It should be observed at this point that it is possible to
envisage using only a single pair of jaws M1, M2 placed on one of
the sides of the collar 21 of the boot 2, preferably the outside.
This pair of jaws associated with a tongue of the type shown in
FIG. 2B does indeed suffice to limit any rotation of the shell
relative to the boot providing the high portion of the shell is
also secured to the skier's tibia by means of a single
self-gripping tape 15 situated immediately beneath said high
portion 11 for the purpose of surrounding the tibia, as shown in
FIG. 9B. Nevertheless, the use of two pairs serves to make the
behavior of the shell more robust and in particular serves to
prevent it from pivoting as a whole about the tongue La.
[0130] Since the width of the open space between the two jaws M1
and M2 is greater than the width of the tongue La, the tongue can
move a little, and this movement causes a limited angular sector of
the shell 10 to move in rotation. Thus, the fastening of the shell
10 on the collar 21 of the boot 2 provides a degree of freedom in
rotation relative to the boot 2 over an angular sector that is
predetermined and limited. It may be observed at this point that
the jaws M1 and M2 may also be positioned so that the tongue is
prevented from moving in rotation. Under such circumstances, the
shell is maximally secured to the boot and knee protection is at
its best. In the event of relative axial rotation of the tibias
giving rise to angular displacement of the longitudinal axis of the
femur relative to the axis of the ski, the knee comes to abut
against the lateral flanges 11a and 11b and prevents the knee being
twisted. Nevertheless, this can reduce skiability.
[0131] It can thus be understood at this point that it is
advantageous to use embodiments of the invention that allow a
limited amplitude of rotation to be obtained. The use of a small
angular sector over which the shell 10 is free to move in rotation
is advantageous from a skiability point of view. Such a freedom to
move in rotation over a limited angular sector does not
significantly degrade the protection conferred by the invention,
since the joints in question have a certain tolerance margin before
being damaged.
[0132] In FIGS. 2D-2E, the jaw-forming elements M1 and M2 are
fastened relative to the boot 2. It should be observed in this
example that at least one of these elements M1 and M2 could be
slidably mounted in order to be able to adjust the lateral space in
which the second connection means 12a and 12b of the shell can
move. This thus makes it possible to adjust the angular sector over
which the tongues La and Lb of the second connection means 12a and
12b of the shell 10 can move in the first connection means 22a and
22b fastened to the collar 21 of the boot 2.
[0133] FIG. 3 show a second embodiment of the invention.
[0134] In this embodiment, the shell 10 has two lateral flanges 11a
and 11b on its high portion 11 that is comparable with the high
portion of the above-described embodiment. The shell 10 has second
connection means 12a and 12b that are different from those of the
above-described embodiment. These connection means 12a and 12b have
orifices for attaching a strap 13 shown in FIGS. 3D and 3E. The
strap 13 is typically riveted in the orifices 12a and 12b.
[0135] The strap 13 is also attached to a support referenced 23
that is mounted on the boots 2, this support 23 constituting first
connection means fastened to the collar 21 of the boot.
[0136] The slackness of the adjustment of the strap 13 or its
pre-calibrated elasticity make it possible to limit rotation of the
shell 10 relative to the boot 2 containing the foot of the skier
S.
[0137] FIG. 3 show a single lateral strap for reasons of simplicity
in drawing. It can be understood that it is necessary to use two
straps, one on either side of the boot 2, in order to limit
rotation in both directions. Nevertheless, it should be observed in
this example that a single strap fastened level with the second
connection means 12a and 12b of the shell as shown in FIG. 3 could
be used with first connection means fitted to the boot 2 in order
to adjust completely movement in rotation of the shell 10 relative
to the boot 2.
[0138] It should also be observed that it is possible to use a
strap for movement in rotation of the shell in one direction
relative to the boot 2 and other means of the type represented by
the guide part shown in the above-described embodiment for limiting
movement in rotation in the opposite direction. Under such
circumstances, a single guide part, e.g. having two jaws M1 and M2,
would be needed for performing the invention.
[0139] FIG. 4 shows a third embodiment that differs slightly from
the second embodiment. This embodiment uses a strap 13 to secure
the low portion 12 of the shell 10 to the boot. In this embodiment,
the strap is fastened in a slot 12a, however its function is
substantially identical to that performed by the strap 13 in FIG.
3.
[0140] Nevertheless, it can be understood that the strap 13 cannot
genuinely prevent upward movement of the shell 10. This movement
would interfere with operation of the invention and could be
troublesome for the skier.
[0141] Thus, an abutment part 24 is placed on the boot 2. This
abutment part 24 is complementary to an abutment element 14, in
this example an orifice in the shell 10. The abutment part 24
serves to position the shell 10 relative to the collar 21 of the
boot 2 in a vertical direction so as to prevent the shell moving
vertically along the skier's tibia.
[0142] Such an abutment part 24 is also used in the embodiment of
FIG. 5. These figures show a guide part 22a suitable for being
fastened directly on a lateral side of the collar 21 of the boot
2.
[0143] The guide part 22a has a rail referenced R that is
terminated by a second abutment part 25, complementary to the
abutment part 24. It can be understood that the abutment part 25
prevents any downward movement of the shell 10 having part of its
low portion 12 shown in FIGS. 5B and 5C. This low portion 12 of the
shell 10 includes a slideway or groove G that is positioned
relative to the rail R by sliding along the rail.
[0144] In the perspective view of FIG. 5C, it can be seen that the
rail R is of a width such that the slideway or groove G can move
forwards and rearwards through a greater or lesser angle. This
flexing angle depends on the clearance present between the rail R
and the slideway G. This enables satisfactory skiability to be
conserved.
[0145] The spacing between the rail R and the slideway G is thus
advantageously adjustable in order to provide control over a few
degrees of movement in rotation of the system about the axis of the
boot 2.
[0146] FIG. 6A shows the shell 10 associated with a single support
for a spacer 30 that is useful for positioning the shell 10
relative to the leg of the skier S. FIG. 6B shows the FIG. 6A
device installed on a skier's leg, which leg is shown in two
extreme positions of flexing.
[0147] FIGS. 7A to 7C are various perspective views of the
functional lateral portions of the spacer 30, which portions are
referenced 30a and 30b. It can be seen that the surfaces of the
functional portions of the spacer 30 are molded to have shapes that
are quite particular.
[0148] These shapes correspond to melding of the surfaces observed
over the condyles CF of the femur F between two preferred
positions, which may for example be the positions of extreme
flexing of the thigh of the skier S as shown in FIG. 6B.
[0149] These shapes correspond to melding of the surfaces observed
over the condyles CF of the femur F between two preferred
positions, which may for example be the positions of extreme
flexing of the thigh of the skier S as shown in FIG. 6B.
[0150] This maximizes comfort for the skier who, between the two
extreme positions, conserves lateral pressure that matches the
skier's morphology, i.e. that is personalized, against the condyles
of the femur. The functional portions 30a and 30b of the spacer 30
are thus not symmetrical, since the sides of the knee have shapes
and deformations that are quite distinct during their flexing
movements. In contrast, symmetry may exist between the
corresponding functional portions for the two knees.
[0151] FIG. 8 shows a preferred embodiment in which the shell 10 is
provided with two functional portions 30a and 30b. This is the
shell adapted for a right knee. The shell for the left knee is
advantageously symmetrical to the shell shown in FIG. 8.
[0152] In this figure, the shell 10 has a central abutment orifice
14 and grooves G, in this example oblong orifices. These grooves G
co-operate with an abutment or a rail as shown in FIG. 5 in order
to allow angularly limited movement in rotation.
[0153] The shell 10 of FIG. 8 also has through holes or orifices O
for receiving a mechanical element that fastens a strap 13. The
strap 13 is a strap of the type shown in FIGS. 3 and 4. Under such
circumstances, the two types of limitation on movement in rotation
of the shell of the invention coexist within a single article.
[0154] Nevertheless, a particularly simple and preferred version
uses only one strap 13 on either side attached permanently to the
shell or to the heel of the boot by means of a hook 23, as shown in
FIGS. 9. Under such circumstances, it is the adjustment of the
strap received in the orifices O that alone determines the angular
sector over which the shell can pivot relative to the boot.
[0155] In FIGS. 9A, 9B, and 10, there can be seen an embodiment of
the shell with said means for fastening the shell to the collar in
which said first and second connection means comprise non-elastic
straps, made up of two first straps 13a that are releasably
fastened or suitable for being releasably fastened to an element 23
on either side of the rear portion of the collar, and two second
straps 13b, 13b-1, 13b-2 that are releasably fastened or suitable
for being releasably fastened (in an orifice O) on either side of
the shell, said first and second straps 13a and 13b having
complementary connection elements 13c, 13d at their free ends that
are suitable for reversibly connecting the free ends of the first
strap 13a with the free ends of the second strap 13b.
[0156] FIG. 13 shows a model of the axial internal rotation of the
tibia leading to angular movement in the horizontal plane between
the femur and the axis of the tibia that is plotted in degrees
relative to time for a skier wearing a device of the invention
(curve AKG) and for a skier not wearing a device of the invention
(curve SKG).
[0157] It can be seen that the internal rotation is very greatly
reduced when the device of the invention is worn by the skier.
Although it is particularly simple to fabricate, and also to
install on a skier's leg, the device of the invention provides
significant improvements in terms of accidents leading to knee
sprain associated with this type of relative axial rotation between
the tibia and the femur.
[0158] Because of its simplicity and its low production cost, the
invention makes it possible to reach a large public. Models may
have standardized lateral flanges preferably associated with a
spacer having functional surfaces calculated on the basis of an
average of the femur condyle surfaces observed in the population
between the two extreme positions of flexing under skiing
conditions.
[0159] Nevertheless, for smaller markets, typically in the field of
competition, the invention also makes it very easy to personalize
the protection device of the invention. For this purpose it
suffices to use a shell of the same kind as is used for consumer
goods in association with functional spacer portions specifically
designed and shaped to correspond with the particular morphology of
a ski champion, for example.
[0160] Finally, it should be observed that various embodiments may
be provided on the principles of the invention as defined in the
claims below. In particular, the movement in rotation of the shell
relative to the boot may be limited to a limited angular sector by
various connection means performing the functions needed in the
invention.
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