Binding for securing a boot or shoe on a touring or cross-country ski

A binding for the heel of a ski boot or shoe used with a cross-country or touring ski. The binding arrangment includes an axial rib on the ski which engages in a longitudinal groove in the bottom of the heel of the ski boot. The heel of the ski shoe has a transverse recess above the groove and a fastening element connected to the ski behind the region of the heel of the boot has a projection which can enter the transverse recess of the heel of the shoe to thus hold the heel against both vertical and transverse movement with respect to the ski. The front of the boot can be fastened to the ski in any desired manner and the shoe, when the heel binding is released, is then free to flex so that the skis can be used for "walking".

BACKGROUND OF THE INVENTION 
The present invention relates to a binding or device for fixing a boot or 
shoe on a touring or cross-country ski. 
Fixing a boot to a cross-country ski is accomplished by binding the front 
of the boot to the ski. Thus the boot is held to the ski by its front or 
toe portion and the heel may be raised considerably off the ski as the 
skier moves. In practice it is thus often difficult to keep the axis of 
the skier's foot aligned with the axis of the ski. 
In order to keep the boot from pivoting with respect to the ski when the 
skier rests his heel on the ski, particularly during descents, the 
assignee of applicant has already described in French Pat. application No. 
7601536 a fixing device in which the heel of the boot has at least one 
slot, in the form of a groove extending along the axis of the ski, while 
the ski has at least one rib disposed along its axis, this rib engaging in 
the groove in the heel of the boot when the skier presses his heels on his 
skis. 
SUMMARY OF THE INVENTION 
The present invention proposes to provide a device for binding a boot on a 
touring or cross-country ski which also improves the retention of the boot 
on the ski particularly during descents, notably with the advantage of 
obtaining better control and conduct of the skis during turns and 
permitting the skier to place his skis in the so-called snow-plow 
position, in which the tips of the skis are brought together, the skis 
forming a V with its point facing to the front. The present invention has 
as its object, as a new industrial product, a binding or fixing device for 
fixing a shoe or boot on a touring or cross-country ski comprising means 
for fixing the front of the boot on the ski and a rib placed along the 
axis of the ski and designed to engage a longitudinal groove in the base 
of the heel of the boot when the skier rests his heel on the ski, 
characterized by the fact that it comprises a fixing device including a 
fixed lower portion, secured to the ski, and having the said rib, and an 
upper portion, connected to the lower portion and able to rotate with 
respect to it between a first position in which a projecting flange 
integral with the upper portion engages a transverse groove in the rear 
face of the heel of the boot above its longitudinal groove, when the rib 
on the lower portion of the fixing device is engaged in the longitudinal 
groove of the boot, and at least one second position in which the flange 
is disengaged from the transverse groove, return means being provided to 
pull the upper portion of the fixing device back against its lower portion 
in each of the positions. 
In one preferred embodiment the heel binding of the device according to the 
invention includes an upper portion constituted of a hollow cap with a 
base which is essentially truncated in shape and ovoid in cross-section 
whose tapered portion is extended to constitute the projection to engage 
in the transverse groove in the heel of the boot, and an upper knob with 
flat transverse sides basically perpendicular to its base, and a lower 
portion comprising means for fixing on the ski, one front plate having the 
longitudinal rib on its upper face, and an enlarged rounded central zone 
in the shape of an upside down pot whose upper end wall has an opening 
traversed by a threaded bolt with its end screwed into a threaded bushing 
preferably truncated in section and fixed to the cap being preferably a 
force-fit in a central opening of the knob. A helical spring surrounds the 
bolt between its head and the upper end wall of the enlarged central zone. 
In one particular form of the embodiment, the end wall of the enlarged 
central zone in the shape of an upside down pot is inclined at an angle 
with respect to the horizontal of, for example, about 15.degree., so that 
the bolt and therefore the upper knob of the cap are tilted at a 
corresponding angle with respect to the vertical, the base of the said cap 
thus equally being tilted at a corresponding angle with respect to the 
horizontal. 
The head of the threaded bolt may advantageously be provided with a slot 
permitting the threaded shaft to be turned with respect to the 
corresponding screwed bushing, for example, with a screw-driver, thus 
adjusting the return force of the spring. 
Of course, with the embodiment of the device according to the invention, 
when the projection, formed by the tapered portion of the base of the cap 
which constitues the upper portion of the fixing device, engages the 
transverse groove of the boot, the effect of the spring holds the boot 
vertically with respect to the ski, combined with a lateral hold due to 
the engagement of the longitudinal groove of the boot with the rib which 
is integral with the lower portion of the binding. When the user wishes to 
disengage the boot all he need do is turn the knob of the upper portion of 
the fixing device with respect to the lower portion around the axis of 
rotation consisting of the threaded bolt and which can turn in the opening 
in the end wall of the enlarged central zone in the shape of an upside 
down pot of the lower portion. It may, for example, rotate through an 
angle of 180.degree., so as to disengage the projection from the 
transverse groove of the boot, this projection being then in the 
disengaged position and turned, for example, toward the back of the ski 
and the skier can then freely lift his heel, the latter still engaging the 
longitudinal groove when the boot is rested on the ski. 
The present invention also has as its object by way of a new industrial 
product, a touring or cross-country ski, characterized by the fact that it 
includes a binding as described above, this binding being mounted on the 
ski behind the area of support for the heel of the boot. 
The present invention also has as its object by way of a new industrial 
product, a boot to be used in touring or cross-country skiing which on the 
one hand has in its front portion any conventional means for fixing the 
boot to a ski, and which on the other hand has in its heel a groove placed 
along the axis of the boot in the base of the heel and a transverse groove 
in the rear face of the heel above the longitudinal groove. 
In order to make the invention more clearly understood, one embodiment will 
now be described by way of non-limiting example with reference to the 
attached drawings.

Referring to the drawing, it will be seen that the fixing device or binding 
according to the present invention includes a lower portion designated as 
a whole by 1 and an upper portion in the form of a hollow cap or knob 2. 
The lower portion 1 has a front plate 3 provided with means for fixing the 
plate to the upper face of the ski, for example, in the form of holes 4 
(FIG. 3) for the passage of screws or similar fastening means. 
This front plate 3 has a rib 5, which can have a triangular section with a 
peak angle of about 60.degree., this rib 5 being disposed axially in plate 
3 so as to extend along the axis of the ski when the binding is fastened 
on the ski. 
The lower portion 1 also has a rounded central boss 6 in the shape of an 
inverted pot whose upper end wall 7 has a central opening 8. 
As FIG. 4 shows more clearly, the end wall 7 of the boss 6 is tilted with 
respect to the horizontal by, for example, an angle of 15.degree., and its 
sidewall is tilted with respect to vertical by the same angle. 
The upper portion 2 of the fastening device or binding has a base 9 which 
is basically tapered and has an ovoid cross-section as FIG. 3 shows most 
clearly. The curved beveled flange portion 10 of base 9 engages, as FIG. 4 
shows, a transverse groove 11 in the upper portion of the rear face of the 
heel of the boot, the boot also having at the base of the heel a 
longitudinal groove 12 by which it can engage the axial rib 5 of the lower 
portion 1 of the fastening device. 
The upper portion 2 has an integral transversely elongated knob 13 
basically perpendicular to base 9 and constituting the gripping element by 
which the skier may grasp the upper portion of the fastening device to 
pivot it with respect to the lower portion 1. 
This pivoting is accomplished by means of a bolt 14 engaged in the orifice 
8 of the bottom wall 7 of the rounded central boss 6 of lower portion 1, 
the threaded end of bolt 14 being screwed into a truncated nut 15 secured 
to upper portion 2 and being a force-fit in a central well or opening 16 
of knob 13 of upper portion 2. 
A helical hold-down spring 17 is also interposed between the head 15 of the 
bolt 14 and the bottom wall 7. 
Surrounding the boss 6 of lower part 1 is a circular wall the top surface 
of which is engaged by the annular bottom surface of the upper part 2. 
Upper part 2 has a pair of diametrically opposed tongues 19 at its bottom 
edge which seat in recesses 20 of the circular wall of lower part 1 to 
prevent accidental rotation of upper part 2, and to hold the part 2 in the 
boot engaging as well as the boot released position. The sides of the 
tongues 19 and recesses 20 are beveled so that turning knob 13 lifts the 
upper portion against the force of spring 17, the spring pulling the upper 
part down when the tongues are aligned with the recesses. 
In the position shown in FIG. 4 which corresponds, for example, to a 
descent position of the skier, the boot is immobilized by its heel with 
respect to the ski both vertically, because of the engagement of 
projection 10 in groove 11 of the heel, and horizontally, because of the 
engagement of rib 5 in longitudinal groove 12 of the heel. 
When the skier wants to resume a normal advance, by walking the skis, after 
a descent, all he need do is turn knob 13 to disengage projection 10 from 
groove 11 of the heel of the boot by rotating the upper portion 2 of the 
fastening device with respect to the lower portion 1. The skier can thus, 
by a 180.degree. rotation, bring projection 10 to point toward the back in 
an opposite position from that shown in the drawing in FIGS. 1, 3 and 4. 
Of course, the hold-down spring 17 causes the upper portion 2 to be pulled 
against lower portion 1 in this position as well as in the position shown 
in FIG. 4 where the projection 10 is engaged in groove 11 of the heel of 
the boot, as in any other rotational position where projection 10 is 
either engaged or disengaged from groove 11 of the heel. The force of the 
hold-down spring 17 may be modified by screwing or unscrewing the threaded 
bolt 14 with respect to the bushing 15 by means of a screw-driver placed 
in a slot in the head 18 of the threaded bolt 14. The respective threads 
of the bolt and bushing are preferably self-locking to prevent accidental 
unthreading. 
As may be seen from the drawing, since the bottom wall 7 of the rounded 
central boss 6 of lower portion 2 is tilted with respect to the 
horizontal, bolt 14 constituting the pivoting axis is also tilted at a 
corresponding angle with respect to the vertical so that base 9 of upper 
portion 2 is tilted at a corresponding angle with respect to the 
horizontal, as knob 13 is with respect to the vertical. 
Although the invention has been described in connection with one preferred 
embodiment, it will be clear that it is in no way limited to this and that 
any desirable modifications may be made without departing in any way from 
the scope or the principles of the invention.