Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Field Of The Invention
This invention relates to a method of sealing in a water-impermeable
manner, the connecting region between a waterproof shoe upper and the insole
region of a shoe by means of a layer of liquefiable material that is
waterproof in the hardened state.
Background Of The Invention
In recent times shoes were manufactured whose shoe body or upper consists
of water-impermeable, and preferably vapor-permeable material. There were
problems with providing a waterproof connection between the upper and outsole
to be attached.
In cementing processes using existing technology, the upper is cemented to
the insole with the aid of cement and to this cemented unit, a sole is applied
which may be an intermediate sole or the direct outer sole. The weak points
in this solution are the areas of cementation between the insole and the
upper, since the bonding cement does not seal the entire transition region
between the upper and the insole. The cement also becomes brittle and thus
water-permeable due to bending stresses during use of the shoe.
To overcome this problem, the unit of shoe upper and insole cemented
thereto has been lined with a sock-like insert of waterproof, vapor-permeable
material. For obtaining the desired shape of the insert, the insert must be
sewn and hot-welded at the seams. This method may be complicated and
expensive and it also may lead to other problems such as creasing and warping.
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Existing technology also includes molding a polyurethane outsole to the
shoe region of a butt-to-butt upper. For doing so, it is necessary to have a
bipartite injection mold that is applied to the upper from both sides
thereof. This injection mold is relatively expensive. Due to the high mold
costs, the shoe manufacturers are restricted to very few sole configurations.
Also, it is not possible to achieve shoes of elegant appearance with such
molded-on outsoles.
SUMMARY OF THE INVENTION
This invention provides a method for sealing the connecting region between
a waterproof shoe upper and the insole region of a shoe, in a
water-impermeable manner by means of a layer of liquefiable material that is
waterproof in the hardened state. The layer is injection molded onto the
connecting region with the aid of an injection mold, characterized in that the
injection mold is applied to the bottom sole of the shoe upper, connected to
the insole region. The mold has a sealing lip assembly upstanding towards the
insole region and extends on both sides of the connecting region to be sealed,
so that the layer is injection molded into the portion confined by the sealing
lip assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows a schematic vertical sectional view of an upper to which an
insole is bonded and an injection mold applied to the upper.
Figure 2 shows a schematic view of an upper to which an insole is bonded
and which has an injection mold applied thereto.
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DETAILED DESCRIPTION OF THE INVENTION
This invention provides an improved method for procuring a connection
between an upper and insole region of a shoe that remains waterproof over a
long period of time. Any type of outer sole can be used with this invention.
This invention relates to a method of sealing in a water-impermeable
manner, the connecting region between a waterproof shoe upper and the insole
region of a shoe by means of a layer of liquefiable material that is
waterproof in the hardened state, the layer being injection molded onto the
connecting region with the aid of an injection mold, characterized in that the
inject;on mold is applied to the bottom sole of the shoe upper, connected to
the insole region, the mold having a sealing lip assembly upstanding towards
the insole region and extending on both sides of the connecting region to be
sealed, and in that the layer is injection molded into the portion confined by
the sealing lip assembly.
This method also enables use of a relatively simple injection mold. The
injection molding die may be provided with an upstanding sealing lip having an
outline that corresponds approximately to the contour of the insole. The mold
has great versatility with respect to dimensions of shoes, since the exact
line of application of the sealing lip to the upper provided with the insole
is not a critical parameter.
Preferably, the contour of the sealing lip extends slightly inward from
the outer margin of the upper. It is possible to apply any desired outersole
to the layer that has been injection-molded to the upper. The molded layer
need not be visible in the final product so that the aesthetic appearance of
the shoe need not be impaired by such a layer.
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The layer preferably comprises polyurethane which is liquefied for
injection molding and is injection molded under a pressure of preferably 3 to
5 atm. This pressure ensures that the liquid material penetrates the region
to be sealed between the insole and upper. This also ensures that the
connection is waterproof.
The upper, preferably the entire upper, may be lined with a waterproof
material that is preferably permeable to water vapor. Materials suitable for
this to use as the liner include expanded polytetrafluoroethylene (PTFE), the
liner of which is described in U.S. Patent 4,599,810, a polyester membrane, or
microporous polyurethane coating.
The present invention is best understood by reference to Figures 1 and 2.
Figure 1 shows a cross-section of an upper 1 attached to an insole 4 by means
of a durable cement or adhesive 3. The upper 1 may consist of different
materials. Figure 1 shows two possibilities. Figure lb shows an upper
consisting of a laminate 7 comprising an outer layer 9, a middle layer 11 of a
water-impermeable, vapor permeable membrane as well as an inner layer 13. The
laminate 7 may be lined on the inside with a lining 15.
Figure la shows an embodiment of an upper comprising an outer layer 17,
such as leather, which is lined with a laminate that serves as a lining and
also contains a water-impermeable, vapor-permeable membrane. Extending from
the outer layer 17, is a lasting allowance 19. The lasting allowance is the
amount of upper material of the shoe that needs to be pulled under in order to
bond the upper to the sole. The lasting allowance in Figure la has a loose end
portion 21 which is not cemented to the insole 4.
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The embodiment shown in Figure lb has a lining 15, preferably designed to
be shorter in the lasting allowance than laminate 7. Only the section of
laminate 15 having the lining is cemented to insole 4. The portion of the
laminate 7 projecting beyond the lining form the loose portion of the lasting
allowance 19.
In Figure la, the outer layer 17 is shorter in the region of the lasting
allowance 19 than the laminate layer 7 applied to the outer layer 17. After
the upper has been cemented to the insole 4, the front end portion 21 of the
laminate 7 remains unconnected with the insole 4.
Figure 1 also shows an injection mold 30 having a sealing lip 31 that is
closed in itself and approximately fol~ows the shape of the insole 4. The
shape of insole 4 can be seen in Figure 2. The cross-sectional view of Figure
1 shows a left-hand sealing lip part 31L and a right hand sealing lip part
31R. During the injection molding operation, the sealing lip parts 31L and
31R abut the lasting allowance 19 under the lasting adhesive 3. The injection
mold 30 is provided with an entrance opening whose exit mouth is located in
the portion between the two sealing lip parts 31L and 31R.
During injection molding, the sealing material 5 is liquefied and injected
into the space confined by the sealing lip 31 under a pressure in the range of
3 to 5 atms. In doing so, the liquid sealing material also penetrates into
the region between the insole 4 and the loose ends 21 of the lasting
allowance. By using this method, the entire space between the insole and the
inner contour of the injection mold located between the sealing lip is filled
with the sealing material. After the sealing material has hardened, a
waterproof closure results wherein the bottom region of the upper 1 is
connected to insole 4.
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This method can also be used in butt-to-butt design. In this case, the
sealing lip 31 of the injection mold 30 is positioned such that the
butt-to-butt seam is located within the portion of the injection mold that is
enclosed by the sealing lip 31.
While the invention has been disclosed herein in connection with certain
embodiments and detailed descriptions, it will be clear to one skilled in the
art that modifications or variations of such details can be made without
deviating from the gist of this invention and such modifications or variations
are considered to be within the scope of the claims hereinbelow.
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