Ski boot

In a ski boot designed to be put on from the rear, the foot-retaining system, located within a rigid shell, on a level with the metatarsus, comprises securing means consisting of two straps. One end of each strap is secured to the shell in the vicinity of the sole of the boot. The foot-retaining system is also provided with an adjustable tension device consisting of a bolt accessible from outside the boot, and nuts. A boot according to the present invention assures satisfactory foot retention in the metatarsal area, distributes the necessary pressure over all or part of the metatarsus, and allows the skier to adjust the loads which he applies.

The invention relates to a ski boot, especially a boot designed to be 
fitted from the rear, and more particularly to a ski boot comprising a 
rigid shell and a foot-retaining system located within the shell on a 
level with the metatarsal bones. 
Ski boots consisting of a shell and a foot-retaining system within it are 
already known. 
According to French Pat. Nos. 1,587,643 (Kleinlagel), 2,075,412 (Lederer) 
and 2,045,321 (Head Ski), ski boots may be equipped with one or more 
straps located between the shell and the soft internal slipper on a level 
with the instep, for the purpose of altering satisfactory retention of the 
foot in the boot. 
The arrangement of the foot-retaining system on a level with the instep 
appears to be preferably for rear-entry ski boots (French Pat. No. 
1,587,642), since in this case the front part of the boot does not allow 
the shell to flex in order to adapt itself to the skier's foot. However, 
this retention of the foot may be considered inadequate by strong skiers 
or racing skiers, especially if it is on a level with the metatarsus. 
Furthermore, in the case of a rear-entry boot, no closure system provides 
satisfactory lateral and vertical retention of the skier's metatarsus. 
In order to overcome this problem, U.S. Pat. No. 3,883,964 (Olin) provides 
a rigid plate located between the shell and the internal slipper and 
secured more or less firmly to the skier's sock by means of two screws 
accessible from the outside. This improves the retention of the foot in 
the metatarsal area. 
However, this system has several disadvantages: 
(1) The direction of the loads applied to the rigid plate between the shell 
and the sock is entirely vertical. The result of this is either poor 
transverse retention of the foot, or excessive vertical pressure to 
provide adequate transverse retention. 
(2) The pressure screws are fitted to the rigid plate on the top of the 
boot on a level with the metatarsus. This relatively weak area must 
withstand the loads applied by the foot and transmitted by the plate, and 
may thus be deformed. 
(3) The loads applied to the rigid plate by the shell are transmitted by 
screws. These heavy local loads may deform the plate and create painful 
pressure points on the top of the metatarsus. 
(4) Since the screws bear upon the shell, the shell absorbs not only the 
loads required to retain the foot, but also all other loads applied 
thereto. For instance, when the skier is leaning forwards, the load and 
deformation applied to the shell are transmitted to the plate and are 
absorbed by the top surface of the metatarsus. 
It is an object of the present invention to provide a ski boot, especially 
a rear-entry ski boot, comprising a foot-retaining system which: 
(a) provides satisfactory vertical and transverse retention of the foot in 
the metatarsal region, while at the same time avoiding excessive vertical 
pressure upon the foot; 
(b) does not require the top of the boot (the weakest area) to absorb any 
load; 
(c) distributes the pressure required for satisfactory foot retention over 
all or part of the upper surface of the metatarsus; 
(d) prevents the loads and deformations of the shell of the boot from 
reaching the metatarsus; and 
(e) may be adjusted by the skier. 
In order to achieve these results the ski boot according to the invention 
comprises a foot-retaining system located within the rigid shell on a 
level with the metatarsal bones, the system comprising a support element 
located between the shell and the skier's foot and partially surrounding 
the latter, and an adjustable device for clamping the support element to 
the foot. 
Furthermore, and according to one basic characteristic of the present 
invention, the clamping device comprises means for securing the support 
element, and an adjustable element for tensioning the securing means which 
at least partly surround the skier's foot. 
This arrangement of the foot-retaining system in the metatarsal area 
eliminates painful pressure points on the joints. Moreover, since the 
securing means and the support element partly surround the skier's foot, 
and since the force providing the foot with satisfactory vertical and 
lateral retention is produced by a tensioning element, the loads are 
distributed over the periphery of the foot. 
Furthermore, the securing means at least partly surrounding the foot 
cooperate with the adjustable tensioning element, and with the support 
element, in providing satisfactory lateral retention of the foot, without, 
in so doing, requiring an additional vertical force, and therefore without 
producing the disadvantages associated with this vertical force, as in the 
case of the boot described in the Olin patent (U.S. Pat. No. 3,883,964). 
In order to eliminate certain defects inherent in the latter patent, the 
securing means are located in the area of the sole of the boot, which is 
rigid and is not deformed when the skier is leaning forward. 
Thus, since the securing means and the support element are completely 
independent of the top of the shell of the boot, they do not transmit the 
loads applied by the metatarsus. This arrangement of the securing means 
and support element therefore prevents deformation and deterioration of 
this relatively weak portion of the boot. 
Conversely, loads applied to the top of the shell, particularly when the 
skier is in forwardly flexed position, are not transmitted to the skier's 
metatarsus, as they are in the case of the above-mentioned patent. 
Since the device for clamping the support element to the foot is 
adjustable, the skier may adapt it to his needs. Preferably, and according 
to another characteristic of the invention, the adjustable device for 
tensioning the securing means comprises an actuating element accessible 
from outside the boot, an arrangement which facilitates adjustment of the 
retention of the foot in the boot. Sufficient play is provided between the 
shell and the actuating element to prevent deformation of the shell from 
being transmitted to the skier's foot. 
Various embodiments of the present invention are conceivable. 
In the first place, the components of the adjustable clamping device and 
support element may cooperate in different ways, for example: 
(a) The securing means may be in the form of two straps each secured by one 
end to one side of the shell, in the vicinity of the sole, the other ends 
of the straps being connected to the adjustable element for tensioning the 
securing means; in this case, the securing means and the tensioning device 
at least partly surround the skier's foot, and the tensioning device 
assumes a position substantially above the metatarsus. 
(b) The securing means may be in the form of a strap, one end of which is 
connected to the shell, near the sole, while the other end is connected to 
the tensioning device located on the other side of the shell, near the 
sole; in this case, the securing means at least partly surround the 
skier's foot. The tensioning device is preferably located on the outside 
of the boot, to prevent it from deteriorating. 
(c) The securing means may be in the form of a strap totally surrounding 
the top of the skier's foot, i.e. all but the sole of the foot. In this 
case, the tensioning device may assume a position wholly or partly within 
the sole of the boot. 
In the second place, the embodiments of the securing means may vary without 
departing from the scope of the present invention; for example, it is 
possible to use either flexible straps or a strip of flexible steel. 
It is also conceivable to use rivets for securing the straps. Furthermore, 
it is desirable to arrange the clamping device at a slight angle to the 
transverse axis of the boot, so that the device runs substantially 
parallel with the tarsal-metatarsal and the toe-metatarsal joints. 
In the third place, the adjustable device for tensioning the support 
element to the foot may be designed in various ways. For example: 
(a) The tensioning device may consist of an adjustable locking element in 
the form of a hook. According to another characteristic of the invention, 
this locking element may be in the form of a hinged hook comprising a 
plurality of notches and an actuating element. This allows the skier to 
adjust the tension of the securing means by operating the hinged hook by 
means of the actuating element. According to a subsidiary characteristic 
of the invention, the adjustable hook locking element may contain at least 
one screw for adjusting the tension of the securing means, in which case 
the screw comprises the actuating element. 
(b) The tensioning device may be in the form of a bolt-and-nut system, the 
rotation of one or the other of these parts altering the tension of the 
securing means. 
The screw preferably has an actuating element at one end. More 
particularly, the actuating element consists of a lever hinged to the end 
of the bolt, pivoting about an axis at right angles to the axis of the 
latter, thus enabling the skier to rotate the bolt by placing the lever 
substantially at right angles thereto, and thus modifying the tension of 
the clamping means. 
If, according to still another characteristic of the invention, the bolt is 
equipped with a locking element to prevent it from turning, this element 
is preferably integral with the shell; a lever such as that described 
above cooperates with the element to prevent the bolt from turning. 
Sufficient play is provided between the lever, in its folded position, and 
the element on the shell (the shape of which complements that of the 
lever), to assure that the loads absorbed by the shell, especially when 
the skier is leaning forward, are not transmitted to the tensioning 
device, and thus to the skier's metatarsus. 
In the fourth place, the actuating element and the tensioning device 
associated therewith may occupy various positions, namely at the side of 
the foot, on the top of the foot, or under the foot. 
In the fifth place, the bolt and nut system which, in various embodiments 
constitute the tensioning device (equipped or not with an actuating 
element), may be designed in various ways as a function of the structure 
of the securing means, for example: 
(a) If the securing means are in the form of two straps each secured by one 
end to one side of the shell, the tensioning bolt has a one left-hand 
thread and one right-hand thread. A nut secured to the free end of each 
strap is threaded onto the said bolt. 
Rotation of the bolt causes the nuts to move in opposite directions, thus 
altering the tension of the straps and the force with which the support 
element is applied to the foot. The left and right-hand threads on the 
bolt may have the same pitch. 
The foot is thus held symmetrically in the boot. However, this symmetry may 
be intentionally eliminated by providing left and right-hand threads of 
different pitches. 
According to a subsidiary characteristic of the invention, the second nut, 
and therefore one of the threads, may be dispensed with. In this case, one 
of the straps is connected to the tensioning device by means of a ring 
sliding on the unthreaded end of the bolt. The movement of this ring is 
controlled by a cam hinged to the unthreaded end of the bolt and pivoting 
at right angles thereto. It is easily understood that the pivoting 
movement of the cam causes, or allows, the ring to move along the bolt in 
relation to the nut, and this alters the tension of the straps. 
If, moreover, the tensioning device comprises an actuating element 
consisting of a lever integral with the cam, then the skier has two ways 
of adjusting the clamping device. He may set the lever at right angles to 
the axis of the bolt, rotate the bolt, and thus displace the nut, which 
provides fine adjustment of strap tension. Or he may displace the sliding 
ring, folding the lever into a position substantially parallel with the 
axis of the bolt; conversely, he may release the ring by lifting the 
lever. The skier may thus easily relax his foot while waiting or for 
walking, and then quickly restore the original pressure without 
readjusting the tension. 
(b) Where the tensioning device is located one one side of the shell of the 
boot and associated with a strap secured by one end to the other side of 
the shell, the bolt of the tensioning device may be threaded and may pivot 
freely in a housing provided for this purpose in the boot. A nut is 
screwed onto the thread and is secured to the free end of the strap, thus 
connecting the strap to the tensioning device. Rotation of the bolt moves 
the nut in relation to the side of the shell to which the tensioning 
device is attached. This alters the tension of the strap and thus the 
pressure applied by the support element to the foot. 
Where the securing means are in the form of a strap, each end of which is 
secured to a nut running upon a threaded rod, the bolt of the tensioning 
device is mounted in the sole of the boot and has a left-hand and a 
right-hand thread. Rotation of the bolt thus causes the nuts to move in 
opposite directions, thus altering the tension of the strap and the force 
with which the strap is applied. 
In the sixth place, the support element partly surrounding the skier's foot 
may be designed in various ways. Although it is not essential to arrange a 
sock between the foot and the support element, it is desirable to do so in 
order to avoid the pain that may be caused by failure to provide the sock. 
According to another characteristic of the invention, the support element 
comprises a rigid plate adapted to the part of the foot against which it 
is designed to bear. This adaptation of the plate to the part of the foot, 
or to the sock, to which it applies pressure, has the effect of 
distributing the pressure over a wide area. 
In this case, the securing means are as a rule in the form of straps 
surrounding the support element, the latter being located between the foot 
and the straps. It should be pointed out, however, that in certain 
variants, the support element may be constituted directly by the strip 
proper or, to be more precise, by the part of the strap in contact with 
the foot.

A detailed description will now be given of FIG. 5, which is a plan view of 
the bones of the foot, showing the area involved in the invention. In 
order to avoid applying pressure to the foot at the joints, it has been 
decided to apply the pressure in metatarsal area 35, defined by the 
tarsal-metatarsal joint 36-35 and the toe metatarsal joint 37-35 (the 
unhatched portion of the figure). This avoids the creation of painful 
pressure points at the joints. 
A description will now be given of FIG. 1 which is a perspective view of 
one embodiment of the invention, and of FIG. 2 which is a cross section 
through a detail of this embodiment. 
The boot, in this case, consists of a shell 3, possibly in several parts, 
equipped with an opening system not shown in FIG. 1, and of a sock 4 
within the shell. The securing means are in the form of two straps, or the 
like, 1 and 1', located between shell 3 and sock 4 on a level with the 
metatarsus. These straps are secured by one end to shell 3, in the 
vicinity of the sole of the boot, by means of a row of rivets 5,5', or the 
like. In this embodiment, the adjustable tension device is in the form of 
a bolt-and-nut system which will now be described. The two free ends of 
the straps are connected (in the central portion of the boot) to nuts 
6,6'. These nuts run upon a bolt 2 having a right and a left-hand thread. 
The bolt is free to rotate and is accessible from outside the boot. By 
rotating knurled knob 7, nuts 6,6' are moved towards or away from each 
other, as are the ends of straps 1,1', thus adjusting the retention of the 
foot in its housing. 
It will be observed in FIG. 2 that play is provided between shell 3 and 
bolt 2. This prevents the deformations of the shell (arising, for example, 
when the skier is leaning forward) from being transmitted to the skier's 
foot. A variation of this first embodiment could be obtained by using a 
single strap and a single nut, with the bolt still located in the central 
plane of the boot. In this case, the bolt is displaced in relation to the 
shell and the skier's foot is pressed against one side of the boot, which 
has the disadvantage of destroying the foot-boot symmetry. 
A description will now be given of FIG. 3, which is a perspective view of a 
second embodiment, and of FIG. 4 which is a cross section through a detail 
of this second embodiment. 
In this variant, the skier's foot is surrounded by a single strap secured 
to one side only of the boot, near the sole, by means of rivets 31. On the 
other side, this strap is tensioned by means of a bolt 32 tangential to 
shell 33 and actuated by a knurled knob 34. This adjustable tension device 
is preferably arranged on the outer side of the boot, in order to 
facilitate actuation and prevent deterioration of the adjustable tension 
device. 
A description will now be given of FIG. 7 which illustrates a third 
embodiment. 
In this case, shell 8 is equipped with a strap 9 surrounding the top and 
sides of the foot and located between shell 8 and sock 10. Each end of 
strap 9 is secured to nuts 11,11' running on the same right-hand and 
left-hand threaded rod 12. This rod has a slot 13, or the like, by means 
of which it may be rotated by the skier, in one direction or the other, in 
order to adjust the retention of his foot in shell 8. 
It should be noted that it is desirable to arrange straps 1,1', 30 and 9 at 
a slight angle to the transverse axis of the boot, so that the straps run 
substantially parallel with the tarsal-metatarsal and toe-metatarsal 
joints of the foot (as shown in FIG. 5). 
The foregoing embodiments all make use of a bolt-and-nut system for 
tensioning the straps. This system may, however, be replaced by a catch, 
hook, or the like, without departing from the scope of the invention. 
The pressure applied by the bolt-and-nut system in each of the foregoing 
embodiments may be transferred to the sock or foot through a 
load-distributing plate designed to reduce the loads applied to the foot. 
In the interests of clarity, this plate is not shown in FIGS. 1, 2, 3, 4 
and 7. 
It should be noted that this plate is not absolutely essential, since the 
support element transmitting the forces which hold the foot in place may 
consist directly of the straps proper or, to be more precise, of the parts 
of the straps in contact with the foot. 
A description will now be given of FIG. 6, which illustrates a plate of 
this kind. Plate 14 is introduced between the straps and the foot, or 
between the straps and the sock. The geometry of this plate must 
correspond to that of the part of the sock or foot with which it is in 
contact, the area of the plate being large enough to reduce the pressure 
upon the foot and eliminate painful pressure points. The plate may have a 
slot 45 across its entire width, through which the strap is passed, in 
order to prevent the plate from assuming a position incompatible with the 
comfort of the foot. 
A description will now be given of FIG. 8, which is a cross section through 
a special tension device, and of FIG. 9 which is a cross section through 
FIG. 8, as seen from the left. This tension device is an improvement to 
the device illustrated in FIGS. 2, 4 and 7. Bolt 15 has a right and a 
left-hand thread carrying nuts 16,16', each connected to one end of straps 
17,17' by split pins 18,18'. 
Bolt 15 is protected by a housing 19 secured to shell 20 and surrounds the 
entire bolt. One end of bolt 15 projects from housing 19, to allow the 
bolt to be actuated. A considerable amount of play is provided between 
shell 20 and bolt 15, to ensure that the retention of the foot is in no 
way altered by deformations in the shell. A lever 21 is hinged to the free 
end of bolt 15, by means of a split pin 22, at right angles to the axis 
thereof, to allow the bolt to be rotated. Since bolt 15 has left and 
right-hand threads, nuts 16,16' move along it in opposite directions when 
it is rotated, thus tightening or loosening straps 17,17'. Lever 21 allows 
the bolt to be rotated through 180.degree. at one time. If it is desired 
to continue to rotate the bolt, lever 21 may be pivoted about its axis 22 
to the opposite position, whereupon the bolt may again be rotated through 
180.degree.. Lever 21 is made of sheet metal bent into the shape of a U, 
the width of the U being sufficient to allow the lever to be folded onto 
housing 19 which then fits into the U. The strap tension is preferably 
adjusted in such a manner that, at the conclusion of the adjustment, lever 
21 is in the vertical position (FIG. 8). Folding the lever in the 
direction of the arrow in FIG. 8, onto housing 19, then locks the bolt, 
preventing it from rotating and makes the tensioning system more compact. 
A description will now be given of FIG. 10, which is a cross section 
through another tension device, and of FIG. 11, which is a cross section 
through FIG. 10 as seen from the left. This is an improvement of the 
special tension device shown in FIGS. 8 and 9. In this design, bolt 23 has 
a single thread upon which a nut 24 runs. One end of strap 25 is secured 
to nut 24 by means of a split pin 26. The second strap, 27, is secured to 
a ring 28 by means of a split pin 29. This ring is adapted to slide freely 
upon the smooth part of threaded rod 23. Straps 25,27 are adjusted, as 
before, by means of a lever 39 hinged, by means of a split pin 40, to the 
free end of bolt 23. It should be noted that, as before, a considerable 
amount of play is provided between ring 28 and housing 41, so that 
deformations of the shell of the boot do not affect the retention of the 
foot. 
Of special interest in this system is the additional tightening of the 
straps by means of an eccentric, or cam, 42 bearing against ring 28 when 
lever 39 is pivoted about its axis 30 in the direction indicated by the 
arrow in FIG. 10. Thus when he is waiting in line, or walking, the skier 
may easily remove pressure from his foot, merely by rotating lever 39 
about axis 40. As soon as the skier wishes to restore the original 
tension, he needs only fold down lever 39, without any further adjustment 
of the strap tension. 
The pressure release obtained merely by lifting lever 29 may be sufficient 
to allow the foot to be withdrawn from the boot. In this case, rotation of 
the bolt is merely a means for adjusting the retention of the foot and is 
not used for removing the boot.