Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present invention relates to a binding and a ski
shoe for use with a cross.county ski and more particularly
to a ski binding, and its combination with the shoe, which
comprises a front jaw adapted to be affixed to the ski and
to hold in position a forwardly extending portion of the I `
sole of the ski shoe. ;
Known ski bindings of this type have a front jaw with a
plurality of upwardIy projecting pins adapted to engage in
bores in the shoe sole. The shoe is held in a resilient strap
10 which may be of varied structure. Ski bindings with snap
closures are also known. Published German Patent Application -~
No. 2,610,041 discloses a bindLng for use with a cross- ~ ;
country~ski, which comprises a st;rrup affixed to the ski
and~rsceiving an extension of ths ski shoe sole which must
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be held in position by a pin passing therethrough. The
pin may be the shaft of a screw which threadedly engages a
cylinder mounted on the stirrup and which may be rotated.
It i~ also possible for the pin to pas~ through the shoe sole
extension transversely and horizontally, in which case it
is formed and secured like a safety pin. This type of
attachment of the sole extension to the binding is time-con-
suming and requires many component part~ los~ of one o which
makes the entire binding useless.
In all of the ~nown multi-component bindings, any of the
components may wear out individually, Fur~hermore, engagement
and disengagement of the shoe is not without problem~ and
takes time. Also, since the underside of the ski shoe sole
is usually ribbed to increa~e the friction and prevent gliding
during a cross-country walk, the hard, ribbed underside of
the sole will soon roughen the ski surface. This will cause
snow and ice to settle in the crevices, which is highly
undesirable.
Conventionally, the soles of ski shoe~ for use with a s
cro3~-country ski are of synthetic resin, and it is desirable
to make these synthetic resin soles so that they do not
warp. However, if a sole i9 resistant to flexure so that
it does not tend to warp and if it extends in a flat plane,
it cannot be used for cross-country skiing because such a
stiff sole will rapidly tire the foot of the skier.
Extensive observations have shown that, even if the shoe
fits well and is held securely in the binding as well as in
the region of the heel, the lateral guidance of the ski is
not optimal since lateral displacements of the forward
portion of the foot and the upper3 surrounding it are
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possible with respect to the shoe sole. Displacements
up to about 10 mm have been observed. This results in
an imprecise guidance of the ski, particularly in curves.
It is a primary object of this invention to improve
bindings for use with cross-country skis and their com-
bination wiJth associated ski shoes by reducing the com-
ponent parts of the binding to a minimum and totally
avoiding any pivoted or loose parts which may wear out,
avoiding various disadvantages of known bindings and pro~
viding a binding which may be readily engaged and disengaged
without the use of the hands of the skier. -
It is another object of the invention to decrease the
stiffness of the forwardly extending sole portion and to
prevent rotation of the sole portion even when subjected
to maximum pressure.
It is also an object of the present invention to improve
a shoe for use in cross-country skiing by providing a lateral
guidance that remains effective even when the shoe sole is
worn.
The above and other objects are accomplished according
to one aspect of this invention with a binding for use
with a cross-country ski and adapted to hold in position
a forwardly extending portion of a ski shoe sole, which
comprises a front jaw adapted to be affixed to the ski,
the front jaw including a stirrup shaped to receive the
forwardly extending sole portion, to deform the forwardly
extending sole portion elastically in an end position of
the sole portion in the stirrup, and to anchor the farward-
ly extending ~ole portion to ~e bi~ding in the end position
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According to another aspect of the invention, there
is provided a combination of a bindiny for use with a
cross-countr~ ski and a ski shoe having an elastically
deformable, forwardly extending sole portion adapted to
be held in position by the binding. The binding comprises
a front jaw adapted to be affixed to the ski, the front
jaw including a stirrup shaped to receive the forwardly I ;-
extending sole portion, the forwardly extending sole portion
being elastically deformed in an end po~ition of the sole
portion received in the stirrup, and the forwardly extending
sole portion including an anchoring part engaging the stixrup
in the end position.
In accordance with yet another aspect of the present
invention, there is provided a ski shoe for use with a
cross-country ski and comprising a sole having an elastically
deformable, forwardly extending sole portion including an ~ :
anchoring part adapted to be deformed elastically and held
in an end position in a stirrup of a binding affixed to the
ski.
This invention also provides a ski shoe for use with a
cross-country ski, comprising a sole means of synthetic resin,
the sole means including a heel portion defining a recess of
V-shaped cros3 section and upwardly projecting lateral edges .
forwardly of the heel portion.
The above and othsr objects, advantages and features of
the invention will become more apparent from the following
detailed description of certain now preferred embodiments
thereof, taken in conjunction with the accompanying schematic :
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drawing wherein
FI~. 1 is a side view, partly in section, of one embodi-
ment of a binding and ski shoe according to the present
invention, -
FIG. 2 is a top view of FIG. l;
FIGS. 3 and 4 are views similar to FIG. 1 and showing
two further embodiments,
FIG. 5 i9 a side elevational view, on an enlarge scale,
showing various optional and preferred details of the so~le
and the forwardly extending sole portion, as well as of the
stirrup, .
FIG. 6 i3 a bottom plan view of the shoe of FIG. 5,
FIG. 7 is a view similar to that of FIG. 1, on an enlarged ;
scale, of another embodiment;
FIGS. 8 to 12 schematically show top view of the forward-
ly extending sole portion incorporating various optional
features,
FIG. 13 is a partial side elevational view, partly in ¦
section, of yet another embodiment;
FIGS. 14 to 17 schematically illustrate, in transverse ::
cross section, comparisons between conventional ski shoe -
soles and a preferred embodiment of the sole means according
to this;nvention,
FIG. 18 is a perspective top view of the sole of FIG. 17, :
FIG. 19 is a bottom plan view of the heel portion of a ~::
sole incorporating a preferred feature of the invention,
FIGS. 20 and 21 are end views of the heel portion, res-
pectively illustrating a conventional engagement o* the heel ~:
portion with ~he ki and the engagement according to FIG. 19:
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FIG. 22 is a transverse section showing a preferred
embodi~ent of the sole,
FIG. 23 illustrates a shoe with the sole of FIG. ~2 and
held on a ski, and
FIG. 2~ and 25 are respectively bottom plan and sectional
views illustrating transverse stiffening inserts for the
sole.
Throughout the drawing, like reference numerals designate
like parts functioning in a like manner.
Referring now to the drawing and first to FIGS~ 1 and 2,
there is shown the forward part of sole 1 of a ski boot, this ~ .
forward part being tapered not to exceed the width of a
cross-country ski and having a further tapered f~orwardly.
extending portion 2. The binding for use with this cross-
cou~ry ski and adapted to hold the forwardly extending sole
portion in position comprises front jaw 3' adapted to be
affixed to the ski, for instance by an adhesive and~or
fastening elements, such as screws or bolts, the illustrated
front jaw of the binding including depending side plates 3i" ' :-
which are screwed to the lateral edges 3" of the ski. ~ne
front jaw of the binding includes stirrup 3 which is a strap
shaped to receive forwardly extending sole portion 2 and to
deform this portion elastically in the illustrated end
position of sole portion 2 in stirrup 3. As shown in bro'.~en
lines in FIG. 1, in its untensioned condition, fon~ardly -
extending sole portion 2 rises substantially above the level
of -the stirrup but when inserted thereinto to subtend the
stirrup, it is depre9sed so that it is yieldingly and firmly
held in stirrup 3 of the bindin~ and is anchored thereto in
l~S~4
the illustrated ~nd position, the tensioning of sole
portion 2 by stirrup 3 assuring a firm grip thereon in
the binding. The forward anchoring part of sole portion
2 yieldingly engages stirrup 3 and has recessed abutment
4 which forms a hook engaging forward edge 6 of stirrup 3.
Front jaw 3' of the binding comprises base plate 29 sup-
porting stirrup 3 and protective edge S projecting upwardly
from the base plate frontward of the stirrup, the upwardly
projecting protective edge conforming generally to the ~ ¦
10 shape of the front part of forwardly extending sole portion 2, 1 ;
as best shown in FIG. 2. The ~tirrup is arranged between the
shoe and the anchoring part of sole portion 2 engaging the
stirrup. Forward edge 6 of the stirrup faces, but is spaced
from, protective edge S. Undercut abutment 4 of the anchoring
part conforms ~o inclined forward edge 6 of the transversely
extending strap constituting stirrup 3.
The forwardly extending sole portion rises from the sole
of the ski boot at an obtuse angle along a transverse line
extending between the forward edge 6 and the rear edge 5
of stirrup strap 3, this line being spaced a distance a
from rear edge 5, i.e. being closer thereto than to the
forward edge of the stirrup. In this manner, a more or
less parallel guide for forwardly extending sole portion
2 through the opening defined between base plate 29 and
stirrup 3 is assured. Since pivot b constituted by the
transverse line whence sole portion 2 rises at an obtuse
angle is offset from rear edge 5 of stirrup 3, the rear-
wardly inclined front edge 6 of the stirrup will be firmly
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anchored in the undercut abutment of anchoring part 4.
In a cross-country ski boot, pivot c about which for-
wardly extending sole portion 2 may be bent in relation
to sole l is spaced rearwardly from binding stirrup 3
so that raising of the heel during cross-country skiing
will not cau~e sole portion 2 to be flexed within the
binding.
The above-described combination has the advantage that,
with the heel ràised, forwardly extending sole portion 2
lO may be simply inserted into the binding until, in the end
position, the undercut abutment in its anchoring part 4 will
snap into engagement with inclined forward edge 6 of stirrup
3, thus fixing the boot in position on the ski. Distance a
wiil be selected in accordare with the elasticity of the sole
material to ma~e certain that no flexing forces will be
transmitted to forwardly extending sole portion 2 when the
heel is raised during cross-country skiing. With anchoring
part 4 at a substantially higher level in its unten~ioned
condition than the stirrup of the binding so that it i9
20 yieldingly depressed thereby when it subtends the stirrup
strap and with the hooking engagement of the anchoring part
and the stirrup strap in the end position, tensioning forces
will always be transmitted upwardly to the stirrup strap
even when the heel is raised to its highest position. P~ `
tective edge S prevents snow from lodging below forwardly
extending sole portion 2, which may form an ice wedge under
anchoring part 4 and make disengagement from the binding
difficult. The protective edge, as shown in FIG. l, is
p=eferably exte ded to the upper edge of sole portion 2,
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thus assisting in the prevention of an accidental dis-
engagement of the ski boot from the binding.
To enable the boot to be readily disengaged without the
use of the skier's hands and bending down, the tip of anchoring
part 4 of forwardly extending sole portion 2 defines a round
notch 7 adapted to receive a point of a ski pole whereby the
sole portion may be engaged and depressed by the ski pole
for disengaging the ski boot from the binding. Upon depress-
ing the anchoring part below the level of stirrup strap 3,
the sole portion 2 may simply be slipped out of the binding.
Affixing the front jaw of the binding to lateral edges
3" of the ski by means of side platQs has the advantage that
the rigidity of the ski is not reduced by tap holes for
screws affixing the base plate to the ski surface. However,
any suitable attachment, including a combination of adhesive
and mechanical fastening, may be used. Also, as shown in
FIG. 1, side pl~es 3"' may have webs 3"" wedging into lateral
edges 3" of the ski for a firmer grip.
As is shown in FIG. 2, front jaw 3' of the binding
may comprise conical guide piece 8 for facilitating the
guidance and insertion of forwardly extending sole portion , ~ ;
2 into the binding and also improving the lateral guidance
of the ski~ As shown in broken lines, the lateral walls
of st~rup 3 also may conically converge to improve the seating
of sole portion 2 in the stirrup.
The modification illu~trated in FIG. 3 differs from that
of FIGS. 1 and 2 by the fact that it omits guide piece 8,
thus 3hortening the binding.
In the embodim-nt oi FIG. 4, the binding has no base plate
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and stirrup 3 is mounted directly on the ski by side plates
3"'. In this embodiment, lodging of snow or ice between
the ski surface and the rising anchoring part of forwardly
extending sole portion 2 in front of the stirrup is prevented
by wedge 9 of an elastic foam material, which is affixed
to the ski frontward of stirrup 3 and is adapted to hold the
forwardly extending sole portion in the end position against
forward movement. The wedge is held in position by a pivotal
or slidable member 10 affixed to the ski.
The enlarged showing of FIG. 5 indicates configurations
of ~tirrup 3 and forwardly extending sole portion 2 which
assure optimal anchoring of these two parts to each other.
Thus~ as shown at 11, the underside of stirrup strap 3 may
be partially inclined with respect to the plane of the surface
of the ski, ie. it may rise in relation thereto in the
direction of the ski boot, or, as shown in broken lines at
11', the entire underside of the stirrup strap may be so
inclined. Furthermore, inclined plane mean~ constituted by
wedge~ 12 extending over part of the width of base plate '
29 are provided to project from the base plate into the opening I
defined between the ~ase plate and the stirrup, this inclined -¦
plane mean3 being adapted to engage corresponding groove
means in the underside of forwardly extending sole portion 2.
Depending on the rigidity or elasticity of the material
forming forwardly extending sole portion 2 and as shown in
broken line~ in FIG. S, transverse ledge 12' may be provided
on the underside of this sole portion and the sole portion
may have a reduced transverse cross section forwardly of the
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ledge. In this manner, the force required for insertion cf
sole portion 2 in the binding and its flexing capacity
may be adjusted within desired limits. The untensioned
condition of sole portion 2, when it does not subtend
stirrup strap 3, is also indicated in this figure, as in
FIG. 1. In the unten~ionad or rest position, the forwardly
extending sole portion must rise to a level sufficiently high
above that of the stirrup that, when this sole portion is
depres~ed and restrained by the stirrup, the upward pres~ure
of sole portion 2 against the underside of stirrup 3, which
it subtend , always assures a firm anchoring of the ski boot
in the front jaw of the binding, even when the heel i8
raised to its highest level during cross-country skiing.
- As shown in FIGS. 5 and 6, forwardly extending sole
portion 2 and sole 1 has laterally extending parts 13 having
a ribbed or corrugated underside and leaving therebetween
a longitudinally extending ~ole part for engagement with
the surface of the ski. The ribbed parts of the sole will
prevent sliding and this modification is particularly useful
with the embodiments of FIGS. 3 and 4.
In the embodiment of FIG. 7, the binding if substantially
of the form shown in FIG. 5, including front jaw 15 com-
prising base plate 29 supporting stirrup strap 16 which has
forward edge 20, the base plate being affixed to ski 14 and
defining an opening with strap 16 for receiving forwardly
extending portion 26 of sole 18 of ski boot 19. Sole
portion 26 has anchoring part 17 whose recessed abutment
21 is engaged by forward edge 20 of the stirrup in the illus-
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trated end position.
Forwardly extending sole portion 26 defines transverseslot 22 extending upwardly fxom the underside of the sole
portion and rearwardly from anchoring part 17 thereof. This
oblique slot in sole portion 26 is so wide and leaves at its
upper and inner end 23 such a thin layer of sole material
that a pivot is defined thereat for pivoting anchoring part
17 in relation to the rear part of sole portion 26. The
sole portion itself is pivotal in relation to sole 18
about pivot 25 rearwardly of stirrup 16.
To avoid extension of anchoring part 17 when subjected
to a tensile force in the direction of arrow 17, steel leaf
spring 28 is embedded in sole portion 26 and extends through~
out its kngth. As shown in FIG. 8, such inserts may take
the form of a loop 34 and other shapes of inserts, such as
bands or grids may be used to the same effect. Also, instead
of steel inserts, it is possible to use another hard material
of less extensibility than the sole material, and if the sole
is an injection-molded synthetic resin, it may simply be
injection molded about such inserts. The inserts may have
a gage of about 1 mm, for example.
If desired, forward edge 20 and conforming abutment
21 may be arcuate so that the corners of anchoring part 17
will be sufficiently depressed when a ski pole engages notch
7 and is pressed down to assure disengagement o-f the anchoring
part from the stirrup strap and enable the ski boot to be
slipped out of the binding. Such an arcuate formation will
also improve the hooking engagement between stirrup and
anchoring part as the ski is moved in various directions.
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In the embodiment of FIG. 7, base plate 29 of the
front jaw has webs 30 extending in the longitudinal
direction of ski 14 and the underside of forwardly ex-
tending sole portion 26 defines corresponding grooves
31 receiving the webs. This improves the guidance of the
ski boot in relation to the binding and also holds the boot
therein against lateral movement. One such web and meshing
groove along the longitudinal center line of the ski or a
plurality of such webs and grooves may be provided.
As shown in the drawing, lengthwise slipping of the ski
boot in the binding may be further prevented by providing ;
transverse webs 32 on the base plate to cooperate with
shoulder or groove 33 in the sole portion 26. These webs
and grooves need not extend over the entire width of
the binding and sole, and are so dimensioned that they do
not interfere with the engagement and disengagement of the
ski boot, being designed to absorb horiæontal forces and
thus relieving tension on anchoring part 17. At the same
time, groove 33 provides an advantageous flexing line in
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cooperation with notched pivot 25, which facilitates cross- ,
,::
country skiing. Generally, these transverse webs and
grooves do not extend to the lateral edges of the base plate
and sole portion 26 so as not to reduce the horizontal
stiffness. Groove 33 is preferably wider than web 32
so that tensile forces and resulting e~tensions of the
sole are distributed over a larger width.
As indicated in broken lines, the ski boot is manufactured
with forwardly extending sole portion 26 enclosing an angle
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with sole 18 of the boot so as to reduce any extension
of sole portion 26 when it is bent down into the binding
and held therein.
In the embodiment of FIG. 8, the forwardly extending
sole portion has a pair of lateral guide faces 35, 36
extending substantially parallel to each other in the
longitudinal direction of the ski for engaging contact
with corresponding extending guide faces of the stirrup.
As indicated hereinabove, the forwardly extending sole
portion tends to be extended by tensile forces transmitting
thereto during skiing. If the lateral engaging faces of
the binding stirrup are strongly conical, i.e. converge,
this leads to looseness impairing the safety of the
binding. Parallel guide faces of a length exceeding any -
possible extension of the forwardly extending sole portion
during skiing will a~sure proper guidance for the boot
in the binding.
The anchoring part 17 is subjected to flexing at the points
of hooking engagement with the stirrup. This is avoided by
providing, as shown in FIG. 9, lateral hooking recesses 37,
38 which retain the vertical hooking movement between anchoring
part 17 and stirrup 16, forces 39, 40 exerted upon the hooking ?-
points pressing against each other.
A similarly functioning anchoring of the forwardly ex-
tending sole portion to the ski binding is o~tained in the
embodiment of FIG. 10 by providing a cut-out 41 in this sole
portion forwardly of the stirrup in the anchoring part of
the sole portion and engaging this cut-out with a corres-
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ponding projection in the front jaw of the binding.
In the embodiment of FIG. 11, the forwardly extendingsole portion 46 has a pair of laterally recessed engaging
faces for hooked engagement with corresponding abutments
in the front jaw, which abutments constitute the binding
stirrup in this embodiment. In this embodiment, the an-
choring part of the forwardly extending sole portion defines
vertical slot 48 of V-shaped cross section extending between I ;
the laterally recessed engaging faces whereby the anchor~ng - 1 ,`
part is divided into two sections 42 and 43 horizontally
displaceable towards each other. In this manner, the for-
wardly extending soLe portion may be elastically defonmed I ~¦
when it is received between the lateral abutments provided ¦ -
by the stirrup of the binding and anchoring part sections
42, 43 are elastically pressed horizontally outwardly against
the stirrup abutments to anchor the forwardly extending
~ole portion to the binding in the end position.
In the modification of FIG. 12, forwardly extending
sole portion 47 define~ slot 49 of V-shaped cross section
dividing the anchoring part in two sections 44 and 45
similar in structure and function to the embodiment of FIG. 11, ~
the facing walls of the two sections defining therebetween , -
a cut-out for engagement with a corresponding projection
of the front jaw of the binding. Thus, the forwardly ex-
tending sole portion may be anchored to the binding by
lateral hooking.
In the embodiment of FIG. 13, forwardly extending
sole portion 50 has a transversely reces~ed groove in its , ;
under=ide, which i~ anchored to a transverse ledge of base
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plate 29 when sole portion 50 is in its end position and
is elastically deformed by stirr~p strap 3 to press t~e
r~cessed groove into engagem~nt with the ledge, thus hooking
sole portion 50 to the binding and anchoring it therein. A
pivot 51 is mounted on the base plate forwardly of the ledge
so that the anchoring part of sole portion 50 may be flexed
thereabout for unhooking the sole portion and enabling the
ski boot to be disengaged from the binding.
While the forwardly extending sole portion has been des- ;
cribed and illustrated as an integral portion of the boot
sole and being of the same material, this need not be so, and
such a forwardly extending portion may, in fact, be attached
to an existing sole in any suitable manner and may be comprised
of any suitable material, including metal.
. j ,
A preferred ski boot structure will be described here-
inbelow in connection with FIGS. 14 to 21. FIG. 14 shows a
transverse cross section taken in the region of the ball of
the foot of a conventional ski boot having a flat sole 52
supported on s~i 53. As is indicated in FIG. 15, in this
region of the largest width of the foot, portions 54 and 55
of the uppers may be readily displaced laterally to assume
positions 55, 56 indicated in broken lines. This interferes
with a secure lateral guidance and ~his disadvantage is overcome
in accordance with one aspect of the present invention in the
manner shown in FIGS. 16 and 17, the invention taking advant-
age of the manufacturing possibilities available by the use
of synthetic resin as a sole material, which enables the sole
to be injection molded.
~o prevent the lateral displacement of parts of the
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uppers, the synthetic resin sole means is provided with
upwardly projecting lateral edges forwardly of the heel ;
portion. In the modification of FIG. 16, the sole means
comprises an outer sole and inner sole 60 with lateral
edges 61 and 62 imparting a lateral stiffness to the
uppers and thereby holding them against lateral displacement.
In the modification of FIG. 17, the sole means is an outer
sole and lateral edges 58 and 59 extend over the uppers
of the shoe, with the same effect. The modification of
FIG. 16 has the advantage that boots of different widths
may ~e provided with different inner soles to adapt the boots
to various foot widths. If desired, the inserts may have
enhanced transverse stiffness in the region of the ball of
the foot so that the impact of the ball on the underlying
ski i8 reduced.
~ he upwardly projecting lateral sole edges must be
flexible in the longitudinal direction of the foot, for which
purpose they define a series of slots 63 to 68 extending
substantially vertically to the sole means and sub-dividing
20 the lateral edges into overlapping sections which cover the -
sides of the foot like the scales of a fish.
Another weak point in conventional boots for use in cross-
country skiing is the connection at the tip of the shoe
between the sole and the uppers. Again taking advantage of
the manufacturing capabilities afforded by the use of moldable
or extrudable synthetic resin, it is preferred to providP
the sole with flap 69 integral with the sole and arranged
to cover the tip of the shoe, as shown in FIG. 18. The flap
to be pulled over the shoe tip and bonded there~o by an adhesive.
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.
This provides an effective and secure connection of the
sole to the uppers at the forward portion of the shoe.
Because the lateral displacement forces exerted upon
the uppers are stronger on the outside than on the inside,
outer lateral edge 70 is proportioned to project to a
higher level than inner lateral edge 71, as shown in FIG. 18.
Since the overlapping edge sections interengage movably, they
do not increase the rigidity of shoe sole 72.
As shown in FIGS. 19, 20, 21, the preferred ski shoe
of the-invention has sole means including a heel portion de~
fining a reces~ of V-shaped cross section defined by diverging
walls 74 and 75, this V-shaped recess engaging a corresponding
web 73 projecting from the ski surface so that the heel may
be held on the ski against lateral displacement. Convention-
ally and as illustrated in FIG. 20, diverging walls 74, 75
extend down to the underside 76 of the heel. As the heel
is lifted and lowered during cross-country skiing, the I -~
corners at the recessed are worn and resultant splinters I ,11
rejecting from the ski surface impair the proper engagement
of the recess with the web. Accordingly and in accordance
with thi~ invention, beveled transition zones 77 and 78
are provided between the underside 76 of the sole and the
V-shaped recess defined between diverging walls 74, 75, as
shown in FIG. 21. In this manner, the zone of engagement
between web and recess is separated from the underside of the ~-~
sole which rests on the ski and any wear of the sole or ski
no longer causes a failure in the proper interengagement
between the recess and web. In addition, the small spaces
defined by the beveled transition zones will enable any snow
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lodge there to be cornpressed therein, rather than to
stay in the interface between the ski and shoe sole.
It is also important to provide a broad support for
the heel to reduce sidewise tilting in relation to the ski.
This is obtained in accordance with the embodiment illus-
trated in FI~. 19 by providing a three-armed web 79, the
V-shaped recess correspondingly comprising rectilinear
center recess portion 80 and two diverging rectilinear rQce~qs
portion~ 81 and 82 extending from an end of the center r~cess
10 portion. The diverging V-shaped recess portions 81, 82
enclose an angle between 90 and 270, preferably not ex-
ceeding 120. 1
The heat insulating qualities of synthetic resin ~ `~
soles may be increased by laminating the same with synthetic
resin films which do not transmit infrared radiation, thus
providing additional protection for the feet of the skier , -
against cold.
Boot~ for usein cross-country skiing must be light
and flexible, particularly below the balls of the feet. ;
20 Therefore, the soles of such boots are necessarily quite
resilient in a transverse direction, which make9 the lateral ~ ;
guidance of the ski very difficult.
Cross-country skisare narrow, in contrast to downhill
skis whose width is about 45 mm. Because of the narrowness ~ -` s
of cross-country ~kis, the feet of the skier, particularly
in the regions of the balls of the feet, overhang the ski
laterally and vertical pushing forc_s up to 150 kg have been
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measured. Under such forces, as indicated in FIG. 22,
the laterally over-hanging portion~ of sole 83 tend to
curve down. The skier, therefore, feels the pressure
of the narrow ski against the sole of his foot, particularly
in the center region. This causes undue fatigue and pain
during a long cross-country run. While it is possible to
reduce or avoid this difficulty by increasing the gauge
of the sole and, thus, its rigidity, this produces a corre~
ponding weight increase, which is undesirable.
As shown in FIG. 22, this difficulty is overcome if
the sole extends in an upwardly curvilinear plane, i.e.
it is concave in a transverse direction. Thus, a downward
force will bring the sole in a flat condition, rather than ¦
curving downwardly over the lateral edges of the ski. Thi9
will relieve the pressure of the narrow ski against the foot
sole and also will stretch the uppers when the overhanging
lateral portions of the sole are straightened so that the I ¦
uppers will be free of undesirable folds produced during
cross-country skiing. s
It has been found in the production of ski boots with ~-
curvilinear soles that it is difficult to mount the uppers -
on the insole. The transverse stif~ness of the sole means,
particularly below the region of the ball of the foot, may be
increased by making the insole of a transversely sculptured
sheet material which provides a strong moment of resistance in
a transverse direction for the overhanging lateral portions
of the sole without imparting any significant resisting to a
rolling motion in the longitudinal direction of the ski. Since
it i9 difficult to find a suitable material having the desired
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rigidity characteristics, the invention provides in the
embodiment shown in FIG. 24 an insole of a rigid but ~hin
sheet material, such as an aluminum sheet or a synthetic
resin sheet, which is bonded to the outer sole in transverse
strips. An aluminum sheet having a gauge of about 0.2 to
0.5 ~n is sufficient for this purpose. In the bottom plan
view of FIG. 24, the lateral edges of a ski are designated
by numerals 91 and 93 while the central axis of the ski
is designated 92. It will be noted that the width of th~e
strips extending beyond ski edges 91 and 93 are widest 1~ -
where the load of the foot e~erts the highest flexing forces
and is reduced gradually from the lateral ski edges towards
the ski axis. Thus, material is saved where it is not needed
to stiffen the sole and the weight of the sole is held as
low as possible. Other strip shapes are possible, of course,
but the illustrated configuration will produce maximu~i stiff-
ness with minimum weight. To form strips 94, transverse
slits 95 end in rounded loops 96 adjacent ski edge 91 and
leave a narrow rim interconnecting all strips to increase
the lateral stiffness of the sole. At this part of the sole,
the strongest pressure forces are transmitted from the foot ~,
to the sole. At the opposite side adjacent ski edge 93,
there is no connection between the insole strips, slots 95
extending to the ends of the strips and the edge of the sole.
As shown in the transiverse section of FIG. 25, which
shows the shoe sole in the region of a ski edge, outer sole
97 carries insole 98 and an upper layer consisting of trans-
verse strips 94. This produces a laminate consisting of
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outer sole, edge of uppers, insole and strips producing
maximum stiffness with a minimum of material and weight.
In most cases, an aluminum strip layer weighing about 2 to
3 grams will su~fice, the weight of the strip layer con- -
figurated according to FIG. 24 being about 2 g while parallel
strips will have a weight of about 3 g, with a sheet gauge
of 0.2 mm. Slits 95 between the strips 94 are very important
because, when the insole is flexed , the absence of such
slits would cause the insole to be compressed only to width ~ I
of the strips, which amounts to an increase in the rigidity
in a longitudinal direction in comparison to a sole without
transverse strips and which may be compressed uniformly
along its entire kngth. The slits separate the strips from
each other.
FIG. 23 shows preferred s~i boot 85 with sole 86
tran~versely curved in the manner indicated in FIG. 22 to
form a done-shaped support particularly for the ball region
of the foot. When the ski is pushed forward while the heel 1
is raised, an optimal angle is obtained between shoe 85 and
ski 87 if the shoe is cut and manufactured to fit the bent
foot so that no force is required to move the shoe into the
raised position shown in FIG. 23. When the ski is slid along
the snow as the shoe sole rests on the ski surface, the weight
of the skier will provide the required force and no muscle
force is needed. The weight of the skier will simply press
sole 86 flatly against the ski and the uppers will be ten-
sioned. Elastic inserts, such as steel strips 88, may be ~;
provided in the sole, particularlyin the region of the ball
.
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of the foot, to increase the transverse rigidity and
resistance to warping of the sole so that the ski may
be properly guided, particularly in curving paths and
in climbs up steep hills. Such reliable transverse
guidance has not been available with conventional cross-
country ski boots.
FIG. 23 also shows two tensile elements 89 and 90
extending along the length of shoe 85 and enhancing the return
of the shoe into its raised position.
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