Boot with upper flexion control

The invention relates to a ski boot including a first element or shell base overlaid by a second element or upper provided with a flexion control device having a shock absorbing element cooperating between the upper and the shell base. A transmission arm connects the top portion of the upper to the shell base via a shock absorbing element inserted between at least one of its ends and the opposing wall of the constituent element of the boot. The transmission arm transmits all of the pivoting forces of the boot with respect to the shell base directly to the shock absorbing element due to its attachment by its two ends to these elements of the boot, and forces the shock absorbing element, sandwiched between the arm of the element, to operate in shearing.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to rigid shell ski boots including a shell 
base overlaid by an upper that is at least partially pivotal. The 
invention also relates to a flexion control device adapted to elastically 
absorb the forces applied by the lower portion of the skier's leg that are 
applied on the upper and force it to pivot with respect to the shell base 
and to ensure its elastic return to the initial position as soon as the 
forces cease. 
2. Description of Background and Relevant Information 
Known boots of the aforementioned type, as described in U.S. Pat. No. 
4,078,322, for example, are generally provided with flexion control 
devices capable of absorbing forces applied by the lower part of the 
skier's leg on the latter over a certain amplitude of pivotal movement of 
the upper. These flexion control devices generally use deformable elastic 
means working in compression and/or flexion and which, when released, 
restore sufficient energy to bring the boot back to its initial position. 
In light of the amplitude of pivotal movement of the upper with respect to 
the shell base that is necessary for obtaining a progressive and flexible, 
therefore comfortable, shock absorption, the most commonly used elastic 
means are springs made of metal, such as steel. Indeed, steel can 
withstand substantial deformation and reassume its initial form quite 
accurately, whether it had been bent, stretched, compressed or twisted a 
number of times. On the contrary, steel springs are oxidation sensitive. 
Therefore, they require protection or treatment and they present risks of 
an ill-timed fracture, particularly following shocks or in the case where 
their maximum permissible compression is exceeded. 
Moreover, conventional metal springs are difficult to integrate into boots 
without encumbering the volume and/or cost thereof. It is particularly the 
case when they are designed in specific shapes to be inserted in the 
general volume of the boot shell as described, for example, in French 
Patent Publication No. 2 498 431. 
For issues related to cost, volume, ease of use and insensitivity to 
oxidation, elastic means made of elastically compressible materials of the 
elastomer type are also used as springs. For example, German Patent 
Document No. 80 20 898 and French Patent Publication No. 2 498 061 
disclose ski boots in which the flexion control devices utilize elements 
made out of elastically compressible material such as elastomer, i.e., a 
viscoelastic material. These elements are inserted with some play between 
the walls of the upper and the shell base, and are they maintained in 
translation between two abutments located in the heel zone, at a distance 
from the journal axis and the upper on the shell base. Thus, when the 
upper pivots on the shell base under the effect of the forces exerted by 
the lower part of the skier's leg and/or the ski, the elastic element is 
compressed between the two abutments and increases in volume in the 
transverse direction by filling more or less the entire space in which it 
is confined. As soon as the pivoting forces cease, the elastic element 
relaxes and brings the upper back to its initial position with respect to 
the shell base, thus ensuring the "elastic return" function. 
These flexion control devices are relatively satisfactory. However, they 
have the disadvantage of necessitating, on the one hand, a special 
protection to avoid infiltration of water, snow, etc., in the housings of 
their elastically compressible elements and, on the other hand, of 
providing reinforcements on the portions that are contiguous thereto. 
Indeed, these elastic elements, when compressed, ensure the retention of 
the upper of the boot in forward pivoting. In so doing, they completely 
fill the space where they are confined and thus tend to deform the walls 
of the upper and of the shell base that are contiguous thereto. 
Furthermore, if water and/or snow infiltrates into their housings, the 
possible pivoting of the upper is disturbed because the elastic elements 
can no longer be compressed completely since a portion of the available 
space is occupied by the water and/or snow. 
Another disadvantage, due to the structure of all the flexion control 
devices whose shock absorbing element is located in the heel zone, is 
related to the poor transmission of forces and/or supports of the lower 
part of the skier's leg from the top of the upper to the shock absorbing 
element. Indeed, since the shock absorbing element is located at a 
significant distance from the top of the upper and the journal axis 
thereof, a large portion of the forces and supports coming from the lower 
part of the skier's leg is diffused in the wall of the upper, from its 
upper edge to its journal axis, then up to the heel zone before biasing 
the shock absorbing element. As a result, this structure of the flexion 
control devices does not make it possible to transmit the biases directly 
and instantaneously but rather delays them, causing a fairly long response 
time, which is disturbing for the skier. 
Boots are also known which comprise rubber-like and thin elastic shock 
absorbing elements that are sandwiched between the walls of the upper and 
of the shell base to absorb vibrations, shocks, etc., i.e., all of the 
displacements of very low amplitude. These shock absorbing elements 
notably reduce the brief forces but do not enable a progressive pivoting 
with an amplitude at least sufficient to allow for a flexion that can be 
perceived by the skier. In fact, such elements do not control the 
flexibility of the upper. 
Other ski boots are provided with elements that have a certain viscosity 
and are inserted between the upper and the shell base to absorb the shocks 
and vibrations. Unlike the elastic shock absorbing elements, these viscous 
elements, that likewise absorb shocks and vibrations of low amplitude, 
enable the pivoting of, the upper by constituting what is referred to as a 
viscous friction. On the contrary, they are incapable of bringing the boot 
upper back to the initial position as soon as the forces and/or the forces 
cease. In fact, these devices only manage a sliding friction from one 
surface to another. 
SUMMARY OF THE INVENTION 
The present invention proposes to overcome the disadvantages of the 
aforementioned flexion control devices in a simple and efficient manner 
guaranteeing both a low amplitude absorption for the brief shocks and 
vibrations, and a progressive absorption of large amplitude for the biases 
and forces maintained with return to initial position as soon as the 
latter cease. The invention also proposes a very perceptible device that 
is capable of transmitting the forces applied on the upper portion of the 
upper immediately and directly to the shock absorbing element. 
An object of the invention is achieved by providing a shock absorbing 
element made of a very thick viscoelastic material that is inserted 
between the upper and the shell base and caused to work in shearing rather 
than in compression, by means of a transmission arm that cooperates 
directly between the top of the boot upper and the shell base via the 
shock absorbing element, the periphery thereof being provided to be 
totally cleared to enable its transverse deformation. 
The ski boot includes a first element or shell base overlaid by a second 
element or upper provided with a flexion control device adapted to absorb 
the supports of the lower part of the skier's leg over a certain pivoting 
amplitude of the upper with respect to the shell base. The flexion control 
device has an elastically deformable shock absorbing means that cooperates 
between the upper and the shell base. The flexion control device is 
constituted by a transmission arm and a shock absorbing element that is 
obtained in a viscoelastic material having the form of a very thick block 
with two approximately parallel surfaces, the transmission arm extending 
from the top of the upper to the shell base which it connects between them 
by means of the shock absorbing element sandwiched by its surfaces between 
at least one of its ends and the opposing boot constituent element. 
Due to this structure, the forces applied on the top of the upper are 
transmitted directly to the shock absorbing element which, sandwiched 
between the end of the transmission arm and the shell base or the upper, 
is forced to work in shearing. Its substantial thickness and elastic 
characteristics determine the shock absorbing conditions, especially in 
amplitude and in progressiveness, as well as the force of elastic return 
to the initial position as soon as the forces cease. 
The boot upper is thus suspended elastically around its pivoting axis on 
the shell base in forward and rearward flexion, its movement amplitude 
being essentially a function of the shearing elastic deformability of the 
shock absorbing element. 
Preferably, the shock absorbing element is located in the lower portion of 
the upper in the heel zone, and the transmission arm, which is elongated, 
extends substantially parallel to the wall of the shell base, one of its 
ends being rigidly fixed to the upper portion of the upper whereas the 
other end, which is free and spaced from the wall of the shell base, is 
connected thereto by means of the viscoelastic shock absorbing element. 
According to a preferred construction mode, the transmission arm is 
generally shaped like a "T" whose upper end, constituted by the horizontal 
bar, is fixed on both sides of the dorsal zone and center of the upper, 
whereas the lower end, ending the vertical bar, is connected to the shock 
absorbing element. 
An improvement to this construction mode comprises providing, on the lower 
portion of the upper in the heel zone where the lower end of the traction 
arm extends, an enveloping edge adapted to mask the shock absorbing 
element, and under which the end of the traction arm slides through an 
opening. 
According to an embodiment, the movement amplitude of the flexion control 
device is limited in the direction of a rearward pivoting from a 
predetermined angular position by means of one abutment interacting 
between the upper and the shell base. 
According to another embodiment, the amplitude of movement of the flexion 
control device is limited in rearward and forward pivoting by means of at 
least one abutment interacting between the upper and the shell base.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The ski boot includes a first element, such as a shell base 1, provided 
with a sole 31 overlaid by a second element, such as an upper 2, mounted 
at least partially pivotal on axes 3, the boot having a flexion control 
device 5 in the dorsal zone 4 of the upper 2. This device 5 is constituted 
by a transmission arm 6 affixed to the top portion 8 of the upper 2, and 
by a shock absorbing element 7 made of a visco-elastic material 
interacting between the upper 2 and the shell base 1 through the inserted 
transmission arm 6. The latter, which is elongated and comparable to a 
"T", for example, as is visible in FIG. 2, is fixed by its upper end 11 on 
both sides of the dorsal zone 4 of the upper 2, at reference numeral 9, 
and by its center 10. It extends substantially parallel to the wall 1' of 
the shell base 1, and its other end 12, which is free and spaced from wall 
1', is connected thereto by means of the shock absorbing element 7. 
The shock absorbing element 7 has the shape of a very thick block that is 
fixed by two opposing surfaces 17 preferably substantially parallel on 
corresponding binding zones 17', one of which is located on end 12 of the 
transmission arm 6, and the other on the wall 1' of the shell base 1. 
In light of the substantial thickness of the shock absorbing element 7, the 
upper 2 is advantageously provided with a transverse edge 13 in its rear 
lower portion 14. This edge 13 is adapted to ensure the sealing between 
the wall of upper 2 and the wall 1' of shell base 1 which is covered in 
the corresponding zone. 
To enable shearing deformations of the shock absorbing element 7, 
transversely to its binding zones 17', its periphery 15 is totally cleared 
or exposed from attachment to other structural elements of the boot, and 
the transverse edge 13 is sufficiently spaced from the binding zone 17' 
located on the wall 1' of shell base 1 to allow for a rearward rocking of 
the upper 2, at least within the elastic limits of the shock absorbing 
element 7. This arrangement makes it possible to avoid any accumulation or 
infiltration of water, snow, etc., between the shock absorbing element 7 
and any one of the constituent portions of the boot which carries it, the 
upper 2 or the shell base 1. Moreover, as the shock absorbing element 7 
operates in shearing, the clearance obtained on its periphery 15 prevents 
the element 7 from being confined and/or constrained against one of the 
walls of the upper 2 and/or of the shell base 1 or between abutments, and 
does not thus require reinforcements to be provided. 
As a result of this construction, upper 2 is elastically suspended around 
its pivoting axes 3, any frontward and/or rearward movement causing the 
simultaneous and direct deformation of the shock absorbing element 7. 
Indeed, since the arm is fixed to the top portion of the upper 2, any bias 
applied thereon is transmitted instantaneously, and practically without 
any loss, to the shock absorbing element 7, which considerably reduces the 
response time. The skier thus benefits from a flexion control device 5 
that is progressive, shock absorbing over a large amplitude, insensitive 
to infiltration of water, snow, etc., capable of returning the upper 2 to 
the initial position as soon as the biases cease, and very perceptible by 
the skier. 
In the embodiment shown in FIGS. 3, 4, 5 and 6, the boot includes a flexion 
control device 5 that is associated with an upper 22 with limited 
clearance in the direction of a rearward pivoting from a predetermined 
angular position by means of an abutment 26-27. This abutment is 
constituted by an edge 26 provided on the wall of the shell base 1, above 
the binding zone of the shock absorbing element 7, and by a complementary 
edge 27 provided on the wall of the upper 2. This abutment 26-27 blocks 
the upper 22 in rearward pivoting in a predetermined angular position, 
with an angle a, with respect to the plane of the sole 31 of shell base 1. 
In this way, the skier can take a rearward support on upper 22 with the 
lower portion of his or her leg while being maintained along a constant 
angle of inclination a commonly referred to as an "advance angle", without 
biasing the shock absorbing element 7 which, in this case, does not 
operate in shearing but in flexion toward the front 28 of the upper 22. 
As shown in FIG. 4, in particular, one can see that flexion in the 
direction of arrow 28 by pivoting about its axes 3 causes, simultaneously 
and in the same direction 28, the displacement of the attachment points 9 
and 10 of the transmission arm 6. (Since the latter is connected to the 
shock absorbing element 7 by its lower end 12) the pivoting movement along 
in the direction results in a longitudinal displacement 29 of the end 12 
which forces element 7 to operate transversely to its binding zones. 
Advantageously, the upper 22 is provided with an enveloping edge 23 in its 
rear lower portion 14. This edge 23 advantageously covers the entire shock 
absorbing element 7 while leaving its periphery free and is provided with 
an opening 24 through which the free end 12 of the transmission arm 6 
passes. The upper 22 thus provided has a relatively continuous outer 
surface into which the flexion control device 5 is perfectly integrated. 
To perfect the continuity, a transverse projection 25 with a progressive 
profile is obtained on the shell base 1 opposite the edge 23 and spaced 
therefrom to allow for the possible evacuation of water and/or snow which 
would have infiltrated between the upper 22 and the shell base 1. 
According to another embodiment, not shown, of the upper 22, an abutment 
limits the amplitude of its frontward pivoting 28 in addition to the 
abutment 26-27 which intervenes in rearward pivoting. In this example of 
construction, it is the abutments that determine the maximum amplitude of 
the possible pivoting of the upper 22. It is understood that this pivoting 
amplitude is advantageously limited to that of the elastic deformation 
acceptable by the shock absorbing element 7. 
The description presented above with reference to FIGS. 1-6 shows the 
implementation of a flexion control device 5 whose viscoelastic shock 
absorbing element 7 is fixed on the shell base 1 in the heel zone, and 
whose transmission arm 6 is affixed to the top portion 8 of the upper 2, 
22. It is to be understood that this flexion control device 5 can also be 
mounted in the reverse, i.e., by fixing the shock absorbing element 7 on 
the top portion 8 of the upper 2, 22, and the transmission arm 6 on the 
shell base 1 in the heel zone. In such example of construction, the 
flexion control device 5 still transmits the biases that are applied on 
the top portion 8 of the upper 2, 22, directly to the shock absorbing 
element 7 which remains constrained to operate in shearing due to its 
attachment on the free end of the transmission arm 6 which is then affixed 
to the shell base 1. 
Another example of possible implementation of the flexion control device 5 
of the upper 2, 22, with respect to the shell base 1 includes connecting 
each of the ends 11 and 12 of the transmission arm 6 to a viscoelastic 
shock absorbing element 7, one end fixed on the upper 2, 22, and the other 
end fixed on the shell base 1. 
The instant application is based upon French Patent Application no. 
95.04859, filed on Apr. 19, 1995, the disclosure of which is hereby 
expressly incorporated by reference thereto in its entirety and the 
priority of which is claimed under 35 USC 119. 
Although the invention has been described with reference to particular 
means, materials, and embodiments, it is to be understood that the 
invention is not limited to the particulars expressly disclosed, but the 
invention extends to all equivalents within the scope of the claims that 
follow.