Binding for cross country skis

A binding for cross-country skis, for use with a skiing boot which has a projection that protrudes in front of the toe of the boot and is engageable with a toe iron, which is connected to the ski, wherein a pin connected to the toe iron extends through the extension when the binding is in position for use.

This invention relates to a binding for cross-country skis, for use with a 
skiing boot which has a projection that protrudes in front of the toe of 
the boot and is engageable with a toe iron, which is connected to the ski, 
wherein a pin connected to the toe iron extends through the extension when 
the binding is in position for use. In the known bindings of this kind for 
cross-country skis, the extension consists of an extension of the sole and 
the toe iron connected to the ski constitutes a pocket, which corresponds 
to that extension in width and height. The extension of the ski boot is 
pushed into the toe iron from the rear. The toe iron and the extension 
have a transverse bore, through which a pin is inserted. A disadvantage of 
such known bindings for cross-country skis resides in that the pin is a 
separate member, which is easily lost, and that the extension is immovably 
held in the pocket and for this reason must be deflected during each step 
of the skier. The deflecting of the extension requires a certain effort 
and also increases the wear. 
It is an object of the invention to eliminate these disadvantages. The 
invention resides essentially in that the toe iron comprises two checks, 
which engage opposite sides of the extension, which is insertable between 
the cheeks from above, the pin is held in the toe iron captively, the 
extension has at least one downwardly open groove, which extends 
transversely to the longitudinal direction of the boot and is adapted to 
receive the pin from below, and locking means are provided which oppose or 
prevent a movement of the extension out of the toe iron. Because the 
extension has a downwardly open transverse groove which is adapted to 
receive the pin from below and because the toe iron consists only of two 
cheeks, which engage opposite sides of the extension, the boot can be 
connected to the ski in a simple manner in that the cross-country skier 
places the boot from above onto the pin, which is held in the toe iron. 
The locking means will then hold the extension in position. The joint 
between the boot and ski is stressed in such a manner that only small 
upwardly directed forces are exerted. For this reason it will be 
sufficient for the locking means to oppose the movement of the extension 
out of the toe iron. The pin cannot be lost because it is captively held 
in the toe iron. The groove flares downwardly to a width which exceeds the 
diameter of the pin so that the placing of the boot into the toe iron can 
easily be accomplished and does not require a high precision. 
In accordance with the invention the design is suitably such that the width 
of the top portion of the groove is at least as large as the thickness of 
the pin, the groove is constricted between its top portion and its bottom 
opening to a width which is smaller than the thickness of the pin, and the 
top portion of the groove is preferably formed as a cylindrical bore in 
which the pin is disposed when the binding is in position for use. Owing 
to this constriction of the groove the pin will snap into the top portion 
of the groove. This constriction in itself tends to hold the extension in 
the toe iron. In a preferred embodiment of the invention, the extension 
has on the underside a bevelled or curved surface in front of the groove, 
so that when the binding is in position for use the extension can be 
pivotally moved forwardly about the axis of the pin. In this case the pin 
constitutes a hinge about which the skiing boot and the extension can be 
pivotally moved so that the extension need not be deflected during each 
step of the skier. In the binding according to the invention the 
confronting inside surfaces of the cheek are preferably at right angles to 
the surfaces of the ski and parallel to each other and to the longitudinal 
direction of the ski so that these cheeks constitute a laterally disposed 
guide for the extension and the boot and the extension can be pivotally 
moved forwardly about the axis of the pin but is held against lateral 
movement as firmly as is required for cross-country skiing. In accordance 
with the invention, the height of the extension suitably exceeds the 
thickness of the sole so that the extension is properly guided between the 
checks of the toe iron and can take up substantial lateral forces. 
In another preferred embodiment of the invention the pin is angled to form 
a U-shaped member, which has a free limb that is pivotally movable to a 
position over the extension. That free limb will then hold down the 
extension and act as locking means which prevent a lifting of the 
extension upwardly out of the toe iron even under considerable forces. The 
extension is suitably provided at its top with a recess and the free limb 
of the U-shaped member formed by the angled pin is adapted to snap into 
said recess in position for use. The top of the extension may comprise a 
ramp, which extends as far as to the recess, so that the free limb can 
easily be raised over said ramp and caused to snap into the recess. The 
pin may be angled to form an S-shaped member, in which an oppositely 
angled portion extends from the free limb of the U-shaped member. Such 
double-angled member can be engaged by a ski pole so that the free limb of 
the U-shaped member can be swung into the recess when it is desired to 
close the binding and can be lifted out of the recess when it is desired 
to open the binding. 
In accordance with the invention, the arrangement may be such that the pin 
comprises a wire core and a sleeve, which surrounds the core and extends 
from one cheek to the other and is rotatable relative to the core. This 
arrangement affords two advantages. The wire core may be thinner because 
the pin is stiffened by the sleeve. Such core is bent in U-shape or 
S-shape and owing to its smaller thickness can be elastically deformed 
more easily so that the free limb of the U-shaped member can be more 
easily caused to snap into the groove. 
Another advantage resides in that the rotation resulting from the pivotal 
movement of the extension and skiing boot now takes place between the 
sleeve and the core. A lubricant may be provided between the sleeve and 
core so that the top portion of the groove in the extension will not be 
worn out. 
In accordance with the invention the binding may be so designed that the 
transverse groove in the extension extends only for part of the width of 
the extension and consists of two sections, which extend from the two 
longitudinal sides of the extension. In a particularly advantageous 
arrangement, each section of the groove has a downwardly flaring portion, 
which is defined on the inside, adjacent to the longitudinal center plane 
of the boot, by an inclined surface, which extends in a plane that 
intersects the longitudinal center plane of the boot below the sole. When 
such extension is inserted into a toe iron in which the retaining pin 
consists of a rod or wire that has been bent substantially in C shape and 
the free ends of the pin enter the groove, an obstruction against a 
movement of the extension out of the toe iron will be provided as soon as 
the extension has been forced down. The inner ends of the retaining pin 
are forced outwardly by the bevelled surfaces and as soon as the axis of 
the inner ends of the pin coincides with the axis of the groove the 
retaining pin will elastically snap into the groove. Additional locking 
means are not required in such case. To enable an opening of such binding, 
the outer edges of the cheeks of the toe iron are preferably provided with 
projections, which extend outwardly and force the inwardly protruding ends 
of the retaining pin outwardly when the retaining pin is pivotally moved. 
A mere pivotal movement of the retaining pin then causes the ends of the 
pin to move out of the groove so that the extension is released. 
In numerous cases it is desired to enable an adjustment of the limit of the 
angular movement of the boot in dependence on individual requirements. The 
angular movement is limited by stop surfaces of the toe iron. To enable an 
adjustment of said limit, the arrangement is preferably such that the toe 
iron comprises a plate, which is slidable in the longitudinal direction of 
the ski and adapted to be fixed in position and said plate has a tapering 
surface which cooperates with a stop surface of the extension. 
The extension is preferably provided on the underside with an elastically 
deformable lug, which covers the opening of the groove. This design 
affords the advantage that dust cannot reach the top portion of the groove 
and the wear is thus decreased.

FIGS. 1 and 2 show cheeks 1 of a toe iron 3, which is connected to a ski 2. 
A pin 4 extends through the cheeks 1. That limb of the pin which faces the 
surface of the ski has an end portion which extends through the cheeks and 
which has been squeezed at 5 so that it cannot be pulled out. The limb of 
the pin 4 faces the surface of the ski and defines an axis 6. In the 
arrangement shown in FIGS. 1 and 2, an extension 7 has been caused to snap 
onto the lower limb of the pin 4 and is thus pivoted on the axis 6. The 
pin 4 is angled to form a U-shaped member and has been pivotally moved 
over a ramp 8 of the extension and caused to snap into the latter. In the 
embodiment shown, the toe iron 3 is fixed to the ski 2 by screws 9. 
The toe iron secured to the ski is separately shown in FIGS. 3,4 and 5. The 
cheeks 1 of the toe iron 3 have apertures 10 for receiving the pin 4. On 
its side facing the ski, the toe iron has apertures 11 for receiving the 
screws 9. Alternatively, the toe iron 3 may be adhesively joined to the 
ski or embedded in the material of the ski. 
FIG. 6 shows a pin 4 which is angled to form an S-shaped member, which has 
a lower limb 12, which defines a pivotal axis 6 for the extension 
protruding in front of the toe of the boot. In FIG. 2, the free end 
portion 13 of the limb 12 has been inserted through the apertures 10 in 
the cheeks 1 of the toe iron 3 and has been deformed so that the free limb 
12 cannot be pulled out of the apertures 10 in the cheeks 1. The S-shaped 
member 4 has a limb 14, which is parallel to the lower limb 12 and has 
been reversely bent therefrom to form a U-shaped member. As is apparent 
from FIG. 1, the limb 14 can be pivotally moved over the ramp 8 of the 
extension 7 to prevent an unintended separation of the extension from the 
pivotal axis 6 when the binding is in position for use. The pin is further 
reversely bent beyond the limb 14 that has been reversely bent to form a 
U-shaped member. As a result, the pin constitutes an S-shaped member and 
has an upper portion 15, which can be engaged in a simple manner by a 
properly shaped ski pole so that the skier while standing can pivotally 
move the limb 14 of the pin 4 over the ramp 8 of the extension which 
protrudes in front of the toe of the boot. 
FIG. 7 is a transverse sectional view showing an embodiment of the lower 
limb 12 of a pin which is similar to the pin 4 shown in FIG. 6. The pin 
consists of a wire core 16 and a sleeve 17 fitted over said core and 
extending from one cheek to the other when the pin has been inserted into 
the toe iron 3. Such pin may comprise an elastic wire of spring steel. The 
sleeve 17 can rotate about the axis 6 in unison with the extension 7 so 
that there will be no friction and no wear in the extension 7. 
The extension which protrudes in front of the sole is shown more in detail 
in FIGS. 8 and 9. The extension 7 shown in FIG. 8 protrudes in front of a 
sole 18 of the boot and has a downwardly open groove 19, which extends 
transversely to the longitudinal direction of the boot. That groove flares 
downwardly to a width a, which exceeds the thickness of the limb 12 of the 
pin 4 or the outside diameter of the sleeve 17 so that the extension can 
be inserted in a simple manner into the toe iron 3, which is provided with 
the pin. The top portion 20 of the groove consists of a cylindrical bore, 
which has a diameter that is substantially as large as the diameter of the 
limb 12 of the pin 4 or the outside diameter of the sleeve 17. In position 
for use, the limb 12 of the pin 4 or the sleeve 17 extends in that 
cylindrical bore 20. Between its bottom opening 21 and its top portion 
formed by the cylindrical bore 20, the groove is constricted at 22 to a 
width b which is smaller than the thickness of the limb 12 of the pin 4 or 
the outside diameter of the sleeve 17. The extension consists preferably 
of a plastic material which has such a resilience that it permits the limb 
12 of the pin 4 or the sleeve 17 to snap into the cylindrical bore 20 but 
substantially opposes an unintended movement of the extension out of the 
toe iron. 
The extension 7 has on the underside a curved surface 23, which is disposed 
in front of the groove 19 and enables a pivotal movement of the extension 
7 about the axis 6, which coincides with the axis of the cylindrical bore 
20. The curvature is such that the extension 7 adjoins the plane of the 
sole after a predetermined angular movement and then opposes a further 
angular movement. The extension 7 is provided on the top with the ramp 8 
which has already been described with reference to FIG. 1 and over which 
the limb 14 of the pin can be pivotally moved to hold the extension 7 more 
firmly in the position for the use of the binding. In that position the 
cylindrical bore 20 which constitutes the top portion of the groove 
engages the limb 12 of the pin or the sleeve 17. As is shown in FIG. 9, 
the ramp 8 does not extend throughout the width of the extension. The axis 
24 of the transverse bore 20, which constitutes the top portion of the 
groove, coincides in the position for use with the axis 6 of the limb 12 
or with the axis of the sleeve 17 and is spaced from the toe edge of the 
sole 18 by a distance c which corresponds to the distance c indicated in 
FIG. 3 between the axis of the bore and that end 25 of the cheeks 1 which 
is near the sole. 
In the extension shown in FIG. 8, the groove tapers from its bottom opening 
21 at an angle .alpha. of about 30.degree. to the constriction 22 between 
the transverse bore 20 and the bottom opening 21 of the groove 19. With 
such an angle of about 30.degree., the extension 7 can be quickly snapped 
onto the limb 12 of the pin 4 or onto the sleeve 17. As has been mentioned 
hereinbefore, the limb 14 of the pin 4 is pivotally moved over the ramp 8 
to snap into the recess 26 on the top of the extension 7 when the binding 
is in position for use. The distance between that recess and the axis of 
the cylindrical transverse bore 20 exceeds the inside distance d between 
the limbs 12 and 14 of the pin 4, which is thus stressed when it has 
snapped into the recess 26. 
In the embodiment shown in FIG. 10 the extension 28 of the boot has a stop 
surface 29. A retaining pin 31 extends through the toe iron 30 and, as is 
clearly apparent from FIG. 11, has been bent to form a substantially 
C-shaped member and has inwardly projecting end portions 32. The groove 33 
does not extend throughout the width of the extension 28 but consists of 
two sections which extend from the two longitudinal sides 34 of the 
extension. Each of said sections of the groove 33 has a portion which 
flares downwardly to the plane 35 of the underside of the boot and which 
is defined adjacent to the longitudinal center plane 37 by an inclined 
surface 36, which extends in a plane that intersects the longitudinal 
center plane 37 at an acute angle. When the extension 28 has been inserted 
into the toe iron 30, the inwardly projecting end portions 32 of the 
retaining pin 31 can be forced outwardly as they engage the inclined 
surfaces 36 of the extension 28 until said end portions 32 snap into that 
portion of the groove 33 which is disposed above the inclined surfaces 36. 
In that case an additional offset portion 38 of the retaining pin 31 is 
not required because the extension 28 cannot move out of the groove in use 
in any case so that such additional locking means are not required. For 
this reason the additional offset portion 38 serves only to relieve the 
inner portion of the groove 33. The toe iron 30 is provided on its outside 
with projections 39, which have been formed by a reverse bending of the 
forward edge of the toe iron. During a forward pivotal movement of the 
retaining pin 31 out of the plane of the drawing, the inwardly projecting 
ends 32 will be forced outwardly in the direction of the arrow 40 and thus 
release the extension 28. These conditions are shown in FIG. 12, in which 
the retaining pin 31 is shown after a forward pivotal movement, during 
which the inwardly protruding ends 32 of the retaining pin have been moved 
out of the groove 33 by the projections 39. 
FIG. 13 shows a deformable projection 42, which covers the groove 41 on the 
underside and prevents an ingress of dust into the groove 41. In this 
case, too, the extension 43 has a stop surface 44, which cooperates with a 
member 47, which is mounted to be slidable in the longitudinal direction 
45 of the ski 46. That member 47 has a portion 48, which cooperates with 
the stop surface 44 and which is provided with a tapering surface. The 
member 47 has slots 49, which enable the member 47 to be shifted and to be 
fixed in the selected position. In this way the pivotal movement of the 
boot in the direction of the arrow 50 can be limited at desired angular 
positions.