U.S. patent number 3,882,561 [Application Number 05/400,667] was granted by the patent office on 1975-05-13 for method of fitting a ski boot.
This patent grant is currently assigned to Hanson Industries Inc.. Invention is credited to Alden B. Hanson, Chris A. Hanson.
United States Patent |
3,882,561 |
Hanson , et al. |
May 13, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Method of fitting a ski boot
Abstract
A ski boot includes a semi-rigid outer shell and a liner
assembly comprising a substantially flexible inner padding member
which forms cavities between the inner padding member and the outer
shell of the ski boot. The cavities are filled with a substantially
non-compressible fitting material, which is flowable during the
fitting process, and thereafter hardened to give firm support and
comfort for skiing. In the preferred embodiment the fitting
material is of a thermoplastic nature.
Inventors: |
Hanson; Alden B. (Boulder,
CO), Hanson; Chris A. (Boulder, CO) |
Assignee: |
Hanson Industries Inc.
(Boulder, CO)
|
Family
ID: |
26910628 |
Appl.
No.: |
05/400,667 |
Filed: |
September 25, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
216080 |
Jan 7, 1972 |
3798799 |
|
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Current U.S.
Class: |
12/142P |
Current CPC
Class: |
A43B
5/0405 (20130101); A43D 999/00 (20130101) |
Current International
Class: |
A43B
5/04 (20060101); A43d 009/00 () |
Field of
Search: |
;12/142R,142P
;36/2.5R,2.5AL |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lawson; Patrick D.
Attorney, Agent or Firm: Merriam, Marshall, Shapiro &
Klose
Parent Case Text
This application is a division of application Ser. No. 216,080
filed Jan. 7, 1972, now U.S. Pat. No. 3,798,799.
Claims
What is claimed is:
1. The method of fitting a ski boot which comprises an outer shell
and a liner assembly disposed within said shell, whereby at least
one cavity is formed therebetween, said method comprising the steps
of:
inserting a thermoplastic fitting material into said cavity;
heating said thermoplastic fitting material to a temperature
substantially above ambient temperature;
shaping said liner assembly about the foot-to-be-fitted;
and thereafter cooling said thermoplastic fitting material to
ambient temperature.
2. The method as described in claim 1, wherein said thermoplastic
fitting material is heated prior to being inserted in said
cavity.
3. The method as described in claim 2, wherein said heated
themoplastic fitting material is injected under pressure into said
cavity.
4. The method of fitting a ski boot which comprises a substantially
rigid outer shell and a liner assembly disposed within said shell,
whereby at least one cavity is formed therebetween, comprising the
steps of:
inserting a thermoplastic fitting material into said cavity;
heating said thermoplastic fitting material to a temperature
substantially above ambient temperature,
shaping said liner assembly about the foot-to-be-fitted; and
thereafter cooling said thermoplastic fitting material to ambient
temperature whereby said thermoplastic fitting material supports
said shaped liner assembly.
5. The method as described in claim 4, wherein said thermoplastic
fitting material is heated prior to being inserted in said
cavity.
6. The method as described in claim 5, wherein said heated
thermoplastic fitting material is injected under pressure into said
cavity.
7. A method of custom filling a ski boot which comprises a
substantially rigid outer shell, and a liner assembly disposed
within said shell, whereby at least one cavity is formed
therebetween, which method comprises:
placing a foot-to-be-fitted within said liner assembly;
heating substantially non-compressible thermoplastic fitting
material to a temperature above ambient temperature;
injecting a quantity of said heated thermoplastic fitting material
into said cavity in order to force said liner assembly into snug
fitting relationship with said foot-to-be-fitted; and
cooling said thermoplastic fitting material.
8. A method of fitting as described in claim 7, in which said
heated thermoplastic fitting material is maintained under pressure
after injection and during cooling.
9. A method of custom fitting a ski boot which comprises a
substantially rigid outer shell, and a liner assembly disposed
within said shell, whereby at least one cavity is formed
therebetween, which method comprises:
placing a foot-to-be-fitted within said liner assembly:
heating a substantially non-compressible thermoplastic fitting
material to a temperature at which it becomes flowable;
injecting a quantity of said heated thermoplastic fitting material
into said cavity whereby said heated fitting material forms said
liner assembly into snug fitting relationship with said
foot-to-be-fitted; and
cooling said thermoplastic fitting material until it becomes
substantially non-flowable.
10. A method of fitting as described in claim 9, in which said
heated flowable thermoplastic fitting material is maintained under
pressure after injection and during cooling until said
thermoplastic fitting material becomes substantially
non-flowable.
11. A method of fitting a ski boot which comprises a substantially
rigid outer shell, a liner assembly disposed within said outer
shell, whereby at least one cavity is formed therebetween, and a
thermoplastic fitting material substantially filling said cavity,
which method comprises:
heating said ski boot and said fitting material to a temperature
substantially above ambient temperature;
inserting a foot-to-be-fitted into said heated ski boot, whereby
said thermoplastic fitting material is deformed so as to form said
liner assembly into snug fitting relationsip with said
foot-to-be-fitted; and
cooling said ski boot and thermoplastic fitting material to ambient
temperature whereby said thermoplastic fitting material supports
said formed liner assembly.
12. A method of fitting in accordance with claim 11 wherein the
amount of thermoplastic fitting material within said cavity is
adjusted while said fitting material is heated.
13. A method of fitting as described in claim 11, in which said
thermoplastic fitting material is maintained under pressure after
said foot-to-be-fitted is inserted and during cooling of said
thermoplastic fitting material.
14. A method of fitting a ski boot which comprises a substantially
rigid outer shell, a liner assembly disposed within said outer
shell, whereby at least one cavity is formed therebetween, and a
substantially thermoplastic fitting material substantially filling
said cavity, which method comprises:
heating said ski boot and said fitting material to a temperature at
which said fitting material becomes flowable;
inserting a foot-to-be-fitted into said heated ski boot, whereby
said thermoplastic fitting material is deformed so as to form-fit
said liner assembly into snug fitting relationship with said
foot-to-be-fitted; and
cooling said ski boot until said thermoplastic fitting material
becomes substantially non-flowable.
15. A method of fitting in accordance with claim 14 wherein the
amount of thermoplastic fitting material within said cavity is
adjusted while said fitting material is heated.
16. A method of fitting as described in claim 14, in which said
thermoplastic fitting material is maintained under pressure after
said foot-to-be-fitted is inserted and during cooling until said
thermoplastic fitting material becomes substantially non-flowable.
Description
The present invention relates to a ski boot and liner assembly for
ski boots or other footwear, and more particularly to a liner
assembly comprising a flexible inner padding member having cavities
molded therein. The liner assembly is adapted to be placed within a
semi-rigid outer shell in order to complete the ski boot. The
cavities, which are preferably molded into the inner padding
member, are adapted to be filled with a substantially
non-compressible fitting material, which permits custom fitting of
the inner padding member to a wearer's foot. Preferably the
cavities surround the entire front and side areas of the wearer's
foot, so that these portions of the foot will be surrounded by the
fitting material after it is injected. While a variety of methods
may be used to custom fit the liner assembly of the present
invention and the semi-rigid outer shell to a wearer's foot, the
preferred fitting methods are premised on injecting a flowable
fitting material into the cavities and permitting the inner padding
member to form around the wearer's foot. The fitting material is
then permitted or caused to solidify and harden to a substantially
non-compressible material. Thus the non-compressible fitting
material provides a skier with firm support, while the padding
member provides padding which is shaped to the skier's foot for
comfort.
Although a wide variety of non-compressible materials may be
employed as the fitting material, such as plaster of paris, epoxy
resins, poly ester resins, rigid polyurethane foam or other
thermosetting materials, it is preferred to use a fitting material
which is theremoplastic, such as a wax or a mixture of wax and
plasticizer. The thermoplastic fitting materials are used by
heating the fitting material to a temperature at which it becomes
readily flowable, placing the foot of the skier being fitted into
the boot assembly, injecting the flowable fitting material into the
cavity between the padding member and the outer shell. The
theremoplastic material is then cooled, whereby it becomes a
non-flowing solid which fits snug and firm, but not tight around
the wearer's foot and ankle. The combination of the non-flowing
solid in the substantially rigid outer shell gives firm support to
the foot and ankle of the wearer for the purpose of allowing the
skier to obtain precise and accurate edge control of his skis,
while the inner padding member provides comfort.
BACKGROUND OF THE INVENTION
Ski boots presently available generally comprise a relatively rigid
outer shell which is typically molded of plastic. Disposed within
the outer shell is an inner member or liner which is relatively
soft and flexible, as compared to the shell. The boot also has one
or more buckles or other suitable fastening means for opening and
closing the boot.
Prior art liners comprise many designs. In some instances, the
liner assembly includes a soft cloth or plastic bag containing a
permanently flowable, putty-like material of the type described in
U.S. Pat. Nos. 3,237,319; 3,402,411 and 3,582,503. Some of these
materials, however, tend to flow away from those portions of the
foot which require support or flow out of the original and desired
location forming an uncomfortable fit.
In other instances the liner comprises a bag containing a plastic,
fibrous or other non-flowable material, but the wearer of the boot
was unable to fit the liner specifically to his foot because the
liner was completed at the factory with no means to custom fit the
boot to a wearer's foot.
Other prior art liners include the use of a thin membrane of
material which surrounds the foot and ankle of the wearer. A
thermosetting foam material is then injected into the space between
the inner wall of the shell and the outer wall of the membrane to
complete the assembly. The foam filled liner has sometimes been
referred to as a "custom-fitted" boot inasmuch as the filling
operation is generally completed in a dealer's shop.
Where boots have been custom fitted to a wearer's foot by utilizing
a foaming material, a number of disadvantages exist. Because foam
will expand to fill a given volume, it is necessary that the
precise amount of foam be injected into the space between the shell
and the membrane; otherwise, the resulting foam padding is much too
hard or too soft. In fitting the boot in which foam is to be
injected, the wearer of the boot has his foot inside the boot
during the foam injection operation. If an excessive amount of foam
is injected, it will, upon expansion, cause a hard padding which
will be of great discomfort and pain to the wearer. It has been
reported that on occasion bones have been broken. Accordingly, it
is incumbent upon an individual who is performing the foaming
operation to employ the proper amount of foam. As a result, it is
necessary for a dealer or manufacturer to have highly skilled
personnel to perform the custom fitting operation. In some
instances, the custom fitting kit sent to a dealer's shop required
a mixing of the foaming ingredients, i.e., isocyanate and polyol,
at the shop before the foaming operation could be undertaken. This
mixing procedure often is quite unpleasant due to the spilling of
ingredients in the mixing process, the heat generated by the
exothermic reaction, the unpleasant odor of the components some of
which are toxic and the clean up problem generated with foaming
systems presently utilized.
Moreover, the time required for initially curing the thermosetting
foam is as much as one hour, which means a person who is being
fitted must have his foot in the boot for such an extended period
of time. Since the foam cures by an exothermic reaction, the person
being fitted may literally get a hot foot during the process.
Additionally, since the foam material is thermosetting, rather than
thermoplastic, the process is irreversible once curing has been
accomplished, therefore the fit of the boot is permanent and cannot
be altered.
SUMMARY OF THE INVENTION
The present invention contemplates a ski boot with a liner assembly
in which the liner assembly provides both padding for comfort of
the wearer's foot and, the capability to custom fit the boot to the
wearer's foot. Thus, the liner assembly has two distinct functions,
namely the custom fitting function of the boot to the foot and
padding function of the foot in the boot.
The present invention relates to a liner assembly for a ski boot or
other footwear which has a substantially semi-rigid outer shell.
The liner assembly is made up of an inner padding member and a
relatively non-compressible fitting material. The inner padding
member of the liner assembly of the present invention comprises a
molded padding member which is adapted to fit within a
substantially semi-rigid outer shell. The outer surface of the
inner padding member is generally complementary to the inside of
the outer shell and the inner surface of the inner padding member
is adapted to surround the wearer's foot and ankle. The inner
padding member is shaped to provide one or more cavities on its
outer surface which cavities are adapted to be filled with a
substantially non-compressible fitting material. A fitting material
is inserted into these cavities preferably during the course of a
fitting and sizing operation to complete the liner assembly.
Alternatively, the fitting material may be placed in the cavities
prior to the fitting operation, and simply rendered flowable during
the fitting operation.
THE INNER PADDING MEMBER
The inner padding member of the liner assembly of the present
invention is preferably sufficiently thick in over-all
cross-sectional areas in order to accomplish the padding function.
The thickness of the inner padding member thickness will vary
depending upon whether the measurement is made where the cavity for
the fitting material has been formed, or at a section where no
fitting material will be employed. In addition to being
sufficiently thick to accomplish the padding function, the inner
padding member must be sufficiently flexible so that it can be
formed to the wearer's foot during the custom fitting process. The
outer surface of the inner padding member is preferably
complementary to the inner surface of the outer shell, except in
those areas which define the cavity. This helps to prevent slippage
of the liner assembly within the outer shell, both during the
fitting operation and thereafter. The placement, size and number of
the cavities which are molded into the padding member may vary over
wide limits, and will depend upon the style of the outer shell in
which the liner assembly is used. For use in a ski boot, it is
generally preferable for the cavities to be adjacent to the ankles
and across the instep of the foot, so that when the fitting
material is injected, the boot assembly provides firm support to
the skier's ankle, instep and the ball of the foot. The padding
member of the liner assembly may be made from various materials
which will be known to those skilled in the art. Basically the
padding member must have a smooth inner surface, free from wrinkles
or similar irregularities, although it may be lined with a fabric
such as terry cloth, fur or plastics having relatively low friction
surfaces or the like. The substance of the padding member is
desirably flexible, in order that it may be deformed to fit the
wearer's foot during the fitting process. While the padding member
may be produced from a number of materials, such as polyurethane
elastomers (both high and low density), polybutadiene homopolymers
and copolymers (foamed or solid), foamed rubber, polyvinyl chloride
and the like, polyurethane foam has been found to be particularly
satisfactory. It has been found that a relatively thin urethane
foam padding member will accomplish the required padding function,
since the accurate fit achieved by the fitting process will reduce
the need for massive padding.
The inner padding member of the liner assembly may be produced in a
variety of sizes, approximating ordinary shoe sizes at least with
respect to the inner dimensions. In this manner, the padding member
may be closely fitted to a wearer's foot. However, it may be
desirable to produce the inner padding member of the liner assembly
in a relatively small number of outside sizes. In other words the
outside areas of the liner which contacts the shell would be the
same for many liners, even though the other inner and/or outer
dimensions were different. For example, liners that cover shoe
sizes from 4 to 13 in three or four widths could have outside
dimensions which fit into 6 sizes of outer shells. In this
embodiment, a retail establishment could carry a complete
assortment of liner assemblies, so that any sized foot could be
accomodated, but all of the liners would fit into one of the small
number of standard sized outer shells. This enables the retailer to
fit any size foot, at a minimum cost of carrying a complete
inventory.
The liner assembly of the present invention may be applied to outer
shells of various design and various materials. While it is obvious
to those skilled in the art that for ski boots, an outer shell that
is substantially rigid is desired, for other uses, such as
orthopedic devices, a relatively flexible shell may be used.
However, it is essential that the outer shell be rigid as compared
to the inner padding member, which must be relatively flexible.
Conventional ski boot outer shells may be used, such as those
produced from polyurethane elastomers, fiber glass reinforced
resins including polyesters, epoxy resins, phenolics, and others
which will be known to those skilled in the art.
Generally the inside of the outer shell and the outside of the
inner padding member should have complementary surfaces, and should
be in face to face contact, except in the area of the cavities and
the access opening of the boot and liner.
In its preferred embodiment, the present invention contemplats the
inner padding member being inserted into the molded ski boot shell,
preferably at the factory. The padding member may be cemented to
the inner surface of the shell and it has been found convenient to
cement the bottom of the padding member to the bottom of the outer
shell. In this embodiment the liner assembly is completed in the
course of a fitting operation when a flowable fitting material is
injected into the cavities.
FITTING MATERIAL
The fitting material employed by the present invention must be a
substantially incompressible, non-flowable solid at body
temperatures and at temperatures slightly above body temperatures,
i.e. temperatures below 110.degree.F., but it must be capable of
softening and flowing during the fitting process. While many
different types of material may be used as the fitting material
including materials which become permanently set after the fitting
process, it is preferred that the fitting material be a
thermoplastic material which is flowable at slightly elevated
temperatures, i.e. temperatures above 120.degree.F. The preferred
thermoplastic fitting material flows when heated to a temperature
of about 150.degree.-180.degree. F., and will cease to be flowable
and solidify, becoming substantially non-compressible, when cooled
to about 115.degree. F. Thus in carrying out the fitting process
the thermoplastic material is heated to at least 150.degree.F.
where it becomes liquid or flowable. A skier to be fitted places
his foot in the padding member, which is disposed within the
semi-rigid outer shell. The liquid thermoplastic material is then
injected into the cavities between the padding member and the outer
shell. Since the temperature of the thermoplastic fitting is
relatively low, there is little or no danger of burning the foot of
the skier being fitted. As the temperature of the thermoplastic
drops to 115.degree. F. or below, the fitting material becomes
solid and incompressible and is shaped to a skier's foot. A boot
employing the liner assembly of the present invention can be
readily refitted, if desired, merely by reheating the thermoplastic
in the cavity or cavities of the inner padding member until it
flows, fitting another foot in the boot assembly, and allowing the
boot assembly to cool until the thermoplastic material
solidifies.
Although thermoplastic materials are preferred as the fitting
materials, any material which can be made flowable in order to
accomplish the fitting, but which later assumes a substantially
non-compressible state may be used. For instance, the present
invention contemplates the use of plaster of paris, epoxy resins,
polyester resins, rigid foams, including polyurethane foams,
polystyrene foams and the like to make up all or part of the
fitting material.
FITTING METHOD
The liner assembly of the present invention includes cavities which
are filled with a substantially non-compressible material in order
to further shape, and size the liner so that it fits the foot well,
and when placed in the rigid outer shell the combination provides
support for the foot and a firm connection between the skier's foot
and the ski. The inner padding member of the liner assembly
preferably is manufactured at the factory whereas the fitting
material preferably is inserted in the course of a fitting and
sizing operation in a dealer's shop. The inner padding member
provides a substantial portion of the flexibility, padding and
other desired characteristics to the liner with the fitting
material serving to provide the remaining features sought, i.e.,
fitting and the sizing the liner to the individual's foot and
ankle. As a result of utilizing the invention disclosed and claimed
herein, the control of the characteristics sought with a liner can
be accomplished by the manufacturer.
Custom fitting of a boot equipped with the liner of the present
invention is preferably accomplished by injecting a flowable
fitting material into the cavity or cavities formed between the
outer shell and the inner padding member, with the foot of the
wearer being in place within the inner padding member. The
preferred thermoplastic fitting material is advantageous in that it
may be used simply by heating it to the point at which it becomes
liquid or flowable. There are no chemicals to mix. The
thermoplastic fitting material may conveniently be premixed at the
factory and shipped to a dealer or shop in a single container. The
fitting operation utilizing the thermoplastic fitting material of
the present invention does not require skilled personnel. The
thermoplastic material of the present invention is merely heated
until it becomes flowable, whereupon it is introduced into the
cavity or cavities until it is vented. The lengthy curing period
associated with the thermosetting materials is obviated. The wearer
only need wait a relatively short time for the warm thermoplastic
to cool to a temperature where it will solidify. Also, with the use
of the thermoplastic the custom fit can be adjusted or repeated to
suit the wearer, since the boot only need be reheated, a suitable
amount of thermoplastic fitting material is added or removed and
the assembly is cooled to give a new custom fit.
BRIEF DESCRIPTION OF THE DRAWING
Other features and advantages are inherent in the structure claimed
and disclosed or will become apparent to those skilled in the art
from the following detailed description in conjunction with the
accompanying diagrammatic drawings.
FIG. 1 shows a perspective view of a ski boot comprising an outer
rigid plastic shell, a liner connected to the back or outer wall 9
of tongue member 13. Access to the rear entry boot as shown in FIG.
1, is accomplished by pivoting tongue member 13 outwardly, away
from shell 11. The foot of a wearer is then inserted into boot 10
from the rear. Subsequently, tongue member 13 is pivoted back in
the position shown in FIG. 1 where it is partially overlapped on
both sides by the rear portion of the sides of shell 11. Boot 10 is
then buckled by inserting loops 17, 17a into buckle member 15.
Loops 17, 17a are then drawn tight with boot 10 being secured shut
by a forward rotation of pivotal buckle member 15.
FIG. 2 and FIG. 4 illustrate inner padding member 12 which is
designed to cover substantially all of the foot and ankle of a
wearer except for the back of the ankle and Achilles tendon area.
The areas not covered by inner padding member 12 are padded by
tongue liner 14 of rigid tongue member 13 as is shown in FIG. 1.
Liner 14 is shaped to mate the inner padding member 12 whereby
inner padding member 12 and tongue liner 14 will combine to enclose
the entire foot and ankle of the wearer.
Referring to both FIG. 2 and FIG. 4 inner surface 20 of inner
padding member 12 is shaped generally to conform to the contour of
a wearer's foot. Outer surface 21 of inner padding member 12 is
preferably shaped to fit substantially to the inner surface 22 of
the shell 11, except in the area of cavity 23 which serves to
provide a space for filling material between the shell and inner
padding member when inner padding member 12 is inserted in shell
11.
The thickness of the cross section of the inner padding member 12
in the area bounded by cavity 23 may be approximately 1/4 inches
whereas the thickness of a cross section through the remainder of
member 12 may be approximately 1/2 inches. Although, the inner
padding member may be a membrane or relatively thin lining member,
it is preferably a flexible, cushion member which serves to provide
desired padding between the foot and the fitting material. Thus the
fitting material does not provide the padding function since it is
a non-compressible material, but the fitting material provides a
support function, whereby it provides support for the skier's foot
and ankle and firm contact between the foot and ski boot outer
shell. In carrying out the support function, the non-compressible
fitting material obviates movement of the foot within the ski boot,
thus providing good control of the skis for the skier.
Cavity 23 of member 12 comprises an inner most surface 35, a
vertical front ankle portion 26 and an arch portion 27. The thicker
section of inner padding member 12, which fits against the inner
surface 22 of shell 11 comprises a toe portion 28, which pads the
wearer's toes; a sole area 29 which serves to pad the sole of the
foot; a heel area 30 for padding the heel, two vertical ankle sides
31, 31a which substantially pad the sides of the ankles; and a
substantially horizontal ankle band 32 which encircles the front
and sides of the ankle top. The marginal edges of heel area 30,
vertical ankle sides 31, 31a and a horizontal ankle band 32 are
adapted to mate with corresponding edges on the tongue liner 14
whereby, when the boot is fastened to a wearer, the foot and ankle
will be enclosed and cushioned by liner 14 and inner padding member
12.
Tongue liner 14 is a separate molded or cast piece adapted to fit
between the heel of a wearer and the inside surface of
substantially rigid wall 9. The tongue 13 and its liner 14 may be
removed from the shell 11, and a high-rise tongue inserted in its
place.
Horizontal ankle ban 32 of inner padding member 12 preferably has
one or more passages 33 commencing at the top of band 32 and
extending through the bottom of the band. It is most preferred to
have at least 2 such passages. A flowable fitting material 24.
which fills cavity 23 between the outer surface of inner padding
member 12 and the inside surface 22 of shell 11, is introduced
through passages 33. While the holes 33 have been illustrated in
FIGS. 2 and 4, it is appreciated that other fluid passage means
could be employed. For example, grooves could be placed in band 32
whereby fluid fitting material would pass between the groove and
the shell. Similarly, fluid passage means may be provided in shell
11.
In order to custom fit and size a boot, using the present
invention, an individual places his foot it the inner padding
member 12, which is disposed inside an outer shell 11. The boot is
closed using tongue member 13 and is secured with buckle 15. The
flowable fitting material 24 is introduced into the cavity 23
formed by inner padding member 12 and inner 22 of shell 11, by
injecting the fitting material through one of the passages 33.
After the material has flowed sufficiently to fill the spaces which
exist between shell 11 and first member 12, the material will vent
through the remaining passage 33. Preferably the vent is closed and
additional fitting material is injected under pressure in order to
fill all of the voids. After the cavity is completely filled, the
skier waits until the fitting material becomes non-flowable, after
which the boots may be removed. Since many materials, including
most thermoplastic materials, shrink in volume upon solidifying,
the pressure used in the fitting process is relieved as the fitting
material solidifies.
The use of thermoplastic fitting material is similar in that
heated, liquid thermoplastic fitting material is injected until it
vents, and then pressurized slightly. The wearer walks about in the
boot while the thermoplastic material is cooling and solidifying.
The wearer need wait only a short time before the thermoplastic
fitting material 24 cools and hardens to the extent it conforms
padding member 12 to the foot and ankle of the wearer. No guess
need be made of the amount of material to use since there will be
only a relatively small change in the volume of thermoplastic
material injected following the injection operation as the
thermoplastic material cools and solidifies. The volume of material
injected will be substantially equal to the volume of the space to
be filled.
While the fitting operation has been described in which the
thermoplastic material is dispensed directly onto the inner most
surface 35 of cavity 23, in some instances it may be desired to
provide a thin membrane bladder into which the thermoplastic
material is injected. Such an embodiment is illustrated by FIG. 2,
in which a bladder 36 is a thin walled member which is shaped to
conform to the shape of cavity 23. The bottom wall 37 of bladder 36
is adapted to seat upon the innermost surface 35 of cavity 23,
whereas the top wall surface 38 of the bladder is adapted, when the
bladder is filled with material, to seat against inner wall 22 of
shell 11.
Bladder 36 is shown in FIG. 2 removed from its assembled position
in cavity 23. Bladder 36, which can be made of neoprene, butyl
rubber, natural rubber, polyvinyl chloride or other suitable
material, is closed except for one or more filling tubes 40 which
are attached to or molded in bladder 36 at the top thereof. Tube 40
is adapted to be inserted in to passage 33 in ankle band 32 of
inner padding member 12 when bladder 36 is placed in assembly in
the cavity 23 of inner padding member 12. In using the bladder
embodiment, it may by advantageous to evacuate the air there from
prior to injecting the fitting material.
Viewing FIG. 3, the cross section taken through the boot 100 in
FIG. 1, padding member 12 seats substantially against corresponding
mating portions of the inner wall 22 of shell 11, except in the
area of cavity 23 where bladder 36 is located. As shown in the
drawing, the bottom wall 37 seats against the innermost surface 35
of cavity 23, whereas the top wall 38 of bladder 36 seats against
inner wall 22 of shell 11 when the bladder is filled with the
fitting material 24.
FIG. 4 illustrates a first member 12 adapted to be used without a
bladder member. The horizontal ankle band 32 is equipped with
filling passages 33, whereby the fitting material may be injected
into the cavity, including arch portion 27 and front portion
26.
Further, the present invention contemplates at least partially
filling the cavity 23, either with or without a bladder, with
thermoplastic fitting material at the point of manufacture, or at
some point in advance of the fitting process. In this embodiment,
the boot equipped with the thermoplastic-filled liner assembly is
heated enough to make the thermoplastic material readily
deformable. The wearer places his foot in the warm boot, assumes a
skiing position and permits the thermoplastic material to cool
until is ceases to be flowable and hardens. Naturally it is
advisable to provide means for excess thermoplastic fitting
material to overflow and to inject additional thermoplastic fitting
material if needed.
Boots equipped with the liner assembly of the present invention may
be refitted by using a substantially similar process. It has been
found that heat generated from a hair drier or a light bulb placed
within such a ski boot for a relatively short period of time will
cause the thermoplastic material to soften sufficiently to
eliminate tight spots in the boot and correct other minor fitting
problems. It has also been found that conventional boot fitting
equipment, e.g., boot press, may be used in conjunction with heat
may be used to eliminate tight spots.
While various suitable thermoplastic fitting materials can be
employed for the liner assembly of the present invention, it has
been found the a material comprising a mixture of paraffin wax, and
a plasticizer serves to provide the desired characteristics for the
thermoplastic material. This material flows easily when heated to a
temperature of about 180.degree., yet rapidly cools to a hardened
condition at room temperature. It will be obvious to those skilled
in the art that many other thermoplastic fitting materials may be
used such as various polybutylenes, and other synthetic resins,
various waxes, heavy oils (both mineral and vegetable) and the like
as well as mixtures of such materials. These materials may be
combined with plasticizers, thickeners, preservatives and the like,
as desired. The thermoplastic material may contain various fillers
such as inert granular or fibrous material, small particles of
foams and any other matter which does not interfere with the
mobility of the thermoplastic when heated. It is necessary that the
thermoplastic material be a non-compressible, non-flowing solid
when in use, but be capable of softening and flowing at
temperatures which will not impair the rest of the boot structure
or the foot of the wearer being custom fitted. Generally it has
been found that materials softening at above 120.degree. F. and as
high as 180.degree.F., but which will solidfy at 115.degree.F. are
adequate, but higher or lower melting materials may be used. The
thermoplastic material can be reheated and cooled for refitting as
often as required without a damage to the thermoplastic
material.
The thermoplastic material may be supplemented in the cavities by
some non-thermoplastic material. For instance strips of
polyurethane foam or other forms or types of foam may be placed in
the cavity. Alternatively, small particles or balls of a foam, such
as polystyrene foam, may be dispersed in the thermoplastic
material. The use of such foamed materials to supplement the
thermoplastic materials will tend to reduce the weight of the
complete boot.
Although the drawings herein primarily depict the liner assembly of
the present invention being used in a rear entry ski boot, it will
be obvious to those skilled in the art that the front or side entry
ski boots and other conventional footwear may be so equipped.
The foregoing detailed description has been given for clearness of
understanding only, and no unnecessary limitations should be
understood therefrom, as modifications will be obvious to those
skilled in the art.
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