U.S. patent application number 10/686159 was filed with the patent office on 2004-04-29 for insert molding apparatus and method.
Invention is credited to Davis, John W., Fisher, Randall K., Noble, Joseph J. JR..
Application Number | 20040078998 10/686159 |
Document ID | / |
Family ID | 25528196 |
Filed Date | 2004-04-29 |
United States Patent
Application |
20040078998 |
Kind Code |
A1 |
Davis, John W. ; et
al. |
April 29, 2004 |
Insert molding apparatus and method
Abstract
An apparatus for making a molded article containing an insert
includes an upper mold half and a lower mold half for mating with
the upper mold half to provide a mold cavity therein. Either mold
half can include a recess, an elevator opening in a lower portion
of the recess, and an inwardly directed lip at an upper portion of
the elevator opening. An elevator mechanism is provided which
includes a lifter for supporting an insert to be secured to the
article during a molding operation, and a lifting arrangement for
raising and lowering the lifter through the elevator opening such
that a peripheral edge of the insert supported on the lifter is
clamped between the lifter and the lip when the lifting arrangement
raises the lifter.
Inventors: |
Davis, John W.; (Cleveland,
TN) ; Fisher, Randall K.; (Germantown, TN) ;
Noble, Joseph J. JR.; (Athens, TN) |
Correspondence
Address: |
SCHERING-PLOUGH CORPORATION
PATENT DEPARTMENT (K-6-1, 1990)
2000 GALLOPING HILL ROAD
KENILWORTH
NJ
07033-0530
US
|
Family ID: |
25528196 |
Appl. No.: |
10/686159 |
Filed: |
October 15, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10686159 |
Oct 15, 2003 |
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09981197 |
Oct 16, 2001 |
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6699028 |
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Current U.S.
Class: |
36/44 |
Current CPC
Class: |
B29D 35/128 20130101;
A43B 7/148 20130101; A43B 7/144 20130101; A43B 17/02 20130101; B29D
35/0063 20130101; A43B 7/1445 20130101; B29D 35/122 20130101 |
Class at
Publication: |
036/044 |
International
Class: |
A43B 013/38 |
Claims
What is claimed is:
1. An apparatus for insert molding, comprising: an upper mold half;
a lower mold half for mating with said upper mold half to provide a
molded part cavity therein; at least one of said lower mold half
and said upper mold half including: an elevator opening; an
inwardly directed lip at a cavity side of said elevator opening;
and an elevator mechanism including: a lifter for supporting an
insert to be secured to a molded article during a molding
operation, and a lifting arrangement for raising and lowering said
lifter through said elevator opening such that a peripheral edge of
the insert supported on said lifter is clamped between said lifter
and said lip when said lifting arrangement moves said lifter
adjacent said inwardly directed lip.
2. The apparatus according to claim 1, wherein said lifting
arrangement includes: a base positioned outside a respective said
mold half on a side opposite said molded part cavity; and a
cylinder mounted to said base and including a movable piston rod
connected with said lifter for raising and lowering said
lifter.
3. The apparatus according to claim 2, wherein said base includes a
recess for mounting said cylinder.
4. The apparatus according to claim 1, further comprising a
retainer removably connected to said respective mold half within
said elevator opening, said retainer including a dam flush with and
removable from an inner wall defining said elevator opening, and
said retainer further including said inwardly extending lip
connected to an end of said dam.
5. The apparatus according to claim 4, wherein said retainer
further includes an outwardly extending connector connected with an
opposite end of said dam and removably secured to a surface of the
respective mold half.
6. The apparatus according to claim 1, wherein said lifting
arrangement includes: a first slide plate having a first inclined
cam surface, said lifter being connected to said first slide plate;
a second slide plate having a second inclined cam surface in
contact with said first inclined cam surface; and a moving
arrangement for sliding said second slide plate relative to said
first slide plate in order to raise and lower said first slide
plate and said lifter.
7. The apparatus according to claim 1, which is adapted for molding
shoe insoles and wherein: said lower mold half includes: two lower
mold cavities corresponding to left and right insoles to be molded;
one said elevator opening in a lower portion of each said lower
mold cavity; and one said inwardly directed lip at an upper portion
of each said elevator opening; said elevator mechanism includes two
said lifters for supporting an insert in correspondence with each
said lower mold cavity; and said lifting arrangement raises and
lowers said two lifters such that a peripheral edge of each insert
supported on each said respective lifter is clamped between said
lifter and the respective lip when said lifting arrangement raises
said lifters.
8. A method for insert molding, comprising the steps of: providing
an upper mold half and a lower mold half for mating with said upper
mold half to provide a molded part cavity therein, at least one of
said lower mold half and said upper mold half including an elevator
opening, and an inwardly directed lip at a cavity side of said
elevator opening; supporting an insert to be secured to a molded
article on a lifter positioned in said elevator opening during a
molding operation; moving said lifter such that a peripheral edge
of the insert supported on said lifter is clamped between said
lifter and said lip when said lifting arrangement moves said lifter
adjacent said inwardly directed lip; supplying a molding material
to said cavity; and closing said mold halves until said article is
formed.
9. The method according to claim 8, further comprising the steps
of: opening said mold halves after said article has been formed;
moving said lifter such that said peripheral edge of the insert
supported on said lifter is no longer clamped between said lifter
and said lip; and removing said formed article from said mold.
10. The method according to claim 8, further including the step of
applying a barrier layer on said insert prior to supporting said
insert on said lifter to prevent said molding material from
penetrating through said insert.
11. The method according to claim 8, further comprising the step of
maintaining the insert in a flat configuration while moving the
lifter to clamp the insert and prior to closing said mold
halves.
12. The method according to claim 11, wherein said step of
maintaining includes the step of placing a support, having
approximately the same shape as the insert, on the insert prior to
raising the lifter in order to maintain the insert in a flat
configuration during the clamping operation, and then removing the
support prior to closing the mold halves together.
13. A molded article containing an insert and being produced by the
method of claim 8.
14. An insole for use with footwear, comprising: a first layer
having a lower shallow recess and a first property selected from
the group consisting of cushioning, hardness, density, resilience
and color; and an insert secured in said recess and being made of a
material of a second said property which is different from said
first said property, said insert having an upper surface secured to
said first layer in said recess, and a peripheral portion of said
upper surface being free and unsecured to said first layer in said
recess.
15. The insole according to claim 14, wherein said first layer
includes: a forefoot portion extending at least to metatarsals of a
foot; a heel portion; a mid portion connecting together said
forefoot portion and said heel portion; an upper surface extending
along said forefoot, mid and heel portions and on which a person
stands; and a lower surface extending along said forefoot, mid and
heel portions, said lower surface including said lower shallow
recess.
16. The insole according to claim 14, wherein said insert has a
barrier layer on an upper surface thereof to prevent a molding
material from penetrating into said insert during a molding
operation.
Description
INTRODUCTION TO THE INVENTION
[0001] The present invention relates generally to a molded article
having an insert embedded therein, as well as an apparatus and
method for making the same.
[0002] It is known to provide shoe insoles with inserts located in
recesses thereof. The material of the insert generally has
different characteristics from the material of the remainder of the
insole to provide a specialized effect, such as a greater degree of
cushioning under specific portions of the foot.
[0003] Generally, such inserts have been attached within recesses
or pockets at the lower surface of a formed insole, such as by
means of adhesives. However, the use of an adhesive provides
various disadvantages. Specifically, it is difficult to maintain
the entire insert in full contact with the insole when securing the
same. This becomes even more evident as the size of the insert
increases. There is thus a problem with product quality and
consistency. Further, in some cases, because of the nature of
materials used to form the insole, it is difficult for the adhesive
to adhere to the insole. This adherence problem can also be due to
the presence of mold release agent residues from the molding
operation. As a result, specialized glues are required. Also, the
operation requires additional labor and handling to glue the
inserts, thereby increasing costs.
[0004] Several attempts have been made to mold inserts directly
into insoles. Examples are described in U.S. Pat. Nos. 4,674,204
and 4,910,886. However, a problem frequently occurs with staining
of the inserts from the molding material. In some cases, because of
the porosity of the insert and the large pressure applied to the
liquid polymer substances during the molding operation, the liquid
penetrates into the insert. This results in an unsightly,
non-uniform or irregular staining of the insert. The penetration of
the molding polymer into the insert also changes the rigidity of
the insert, that is, making it harder, and thereby changing the
performance thereof.
[0005] As mentioned above, fluid polymer-forming materials
sometimes tend to flow into the porous structure of the inserts due
to the high pressure in the cavity. As an example, there is a
chemical reaction with liquid urethanes (preferred materials for
making many types of insoles), which releases a gas such as
CO.sub.2. This chemical reaction causes the urethane components to
expand from 120% to 200%-300% of the original volume of the liquid
urethane. Since the mold is a closed mold and since the liquid
urethane expands therein, there is a large increase in internal
cavity pressure, so that a large external pressure must be applied
to maintain the mold in a closed condition. Therefore, there is a
pressure drop of about 15 to 20 psig (1.03 to 1.38.times.10.sup.5
Newton/meter.sup.2) across the inserts, that is, from the upper
surfaces of the inserts to the lower surfaces thereof. Also, the
inserts are open to atmospheric pressure at their sides. Because of
this, the liquid urethane flows into the cells of the porous
structure of the inserts, which result in the inserts becoming more
rigid and less resilient, while also causing the aforementioned
staining.
[0006] In addition to the penetration through the insert, the
liquid urethane tends to leak around to the underside of the insert
during the molding operation, between the insert and the surface of
the mold, causing a thin overcoat layer on the exposed surface of
the insert around the edges of the insert. Any seals which are
provided to prevent migration of the liquid urethane around the
insert during the molding operation have not been very successful,
and still permit this type of overflow to the underside. A reason
for this overflow is the large pressure applied to the liquid
urethane during the molding operation. As a result, this overflow
layer provides an unsightly visual defect on the bottom surface of
the insole. Because such overflow layers are not uniform, the
insoles have an appearance of poor quality.
[0007] There is a further problem with such molded inserts.
Specifically, it is difficult to maintain the position of the
inserts during the molding operation as liquid polymer components
are introduced into the mold, since the inserts tend to float on
the liquid polymer.
SUMMARY OF THE INVENTION
[0008] Accordingly, it is an object of the present invention to
provide a molded article having an insert embedded therein, as well
as an apparatus and method for making the same, that overcomes
problems with the aforementioned prior processes.
[0009] It is another object of the present invention to provide a
shoe insole having a properly positioned insert embedded therein,
as well as an apparatus and method for making the same, in which
there is no staining or overflow layer on the inserts.
[0010] It is still another object of the present invention to
provide a shoe insole having an insert embedded therein, as well as
an apparatus and method for making the same, in which a retainer
with an upper lip is provided around the periphery of each insert
during the molding operation to provide a seal that prevents flow
of the liquid urethane around the peripheral edges of the insert
and also properly positions the inserts into the insert cavity of
the insole.
[0011] It is yet another object of the present invention to provide
a shoe insole having an insert embedded therein, as well as an
apparatus and method for making the same, having an elevator
mechanism that permits the inserts to be inserted into the dammed
area and under the lip and thereafter clamps the peripheral edges
of the inserts between the elevator mechanism and the lip to
provide a seal against the flow of molding material under the
insert.
[0012] It is a further object of the present invention to provide a
shoe insole having an insert embedded therein, as well as an
apparatus and method for making the same, in which a barrier layer
may be provided on a permeable insert in order to prevent
penetration of the liquid molding material into the insert during
the molding operation.
[0013] It is a still further object of the present invention to
provide a shoe insole having an insert embedded therein, as well as
an apparatus and method for making the same, that is easy and
economical to make and use.
[0014] In accordance with an aspect of the present invention, an
apparatus for making a molded article containing an insert includes
an upper mold half and a lower mold half for mating with the upper
mold half to provide a mold cavity therein. Either mold half can
include a recess, an elevator opening in a lower portion of the
recess, and an inwardly directed lip at an upper portion of the
elevator opening. An elevator mechanism is provided which includes
a lifter for supporting an insert to be secured to the article
during a molding operation, and a lifting arrangement for raising
and lowering the lifter through the elevator opening such that a
peripheral edge of the insert supported on the lifter is clamped
between the lifter and the lip when the lifting arrangement raises
the lifter.
[0015] Any lifter actuation mechanism can be used. One such lifter
mechanism includes a base positioned below the lower mold half, and
a cylinder mounted to the base and including a movable piston rod
connected with the lifter for raising and lowering the lifter. The
base includes a recess for mounting the cylinder.
[0016] In one embodiment, a retainer is removably connected to the
lower mold half within the elevator opening. The retainer includes
a dam flush with and removable from an inner wall defining the
elevator opening, as well as the inwardly extending lip which is
connected to an upper end of the dam. The retainer further includes
a lower outwardly extending connector connected with a lower end of
the dam and removably secured to a lower surface of the lower mold
half.
[0017] In another embodiment, the lifting arrangement includes an
upper slide plate having a lower inclined cam surface, the lifter
being connected to the upper slide plate; a lower slide plate
having an upper inclined cam surface in contact with the lower
inclined cam surface; and a moving arrangement for sliding the
lower slide plate relative to the upper slide plate in order to
raise and lower the upper slide plate and the lifter.
[0018] Preferably, for producing shoe insoles, the lower mold half
includes two such recesses corresponding to left and right insoles
to be molded, one elevator opening in a lower portion of each
recess, and one inwardly directed lip at the upper portion of each
elevator opening. In such case, the elevator mechanism includes two
lifters for supporting an insert in correspondence with each
recess; and the lifting arrangement raises and lowers the two
lifters such that a peripheral edge of each insert supported on
each respective lifter is clamped between the lifter and the
respective lip when the lifting arrangement raises the lifters.
[0019] In accordance with another aspect of the present invention,
a method for making a shoe insole includes the step of providing an
upper mold half and a lower mold half for mating with the upper
mold half to provide a molded part cavity therein, either the lower
mold half or the upper mold half including an elevator opening, and
an inwardly directed lip at a cavity side of the elevator opening.
Then, an insert to be secured to the shoe insole is supported on a
lifter positioned in the elevator opening during a molding
operation. The lifter is then moved such that a peripheral edge of
the insert supported on the lifter is clamped between the lifter
and the lip when the lifting arrangement moves the lifter adjacent
the inwardly directed lip, and a molding material is supplied to
the cavity. The mold halves are then closed while the molding
material fills the cavity, and the insole is formed.
[0020] Further, according to the method, the mold halves are opened
after the insole has been formed. The lifter is lowered after the
insole is formed to facilitate demolding such that the peripheral
edge of the insert supported on the lifter is no longer clamped
between the lifter and the lip. Thereafter, the formed insole can
be removed from the mold.
[0021] If the insert is a permeable material such as an open-cell
foam, then a barrier layer may be provided on the insert prior to
introducing the molding material in contact with the insert to
prevent the molding material from penetrating through the insert.
If the insert is not a permeable material, no barrier layer is
usually required.
[0022] Any mechanism can be used to hold the insert in a flat
position during lifter actuation, and which is removed when the
insert is clamped in place. As an example, a weight may be provided
having the same shape as the insert and positioned on top of the
insert prior to raising the lifter in order to keep the insert flat
and facilitate clamping of the insert under the lip around the
entire insert periphery. The weight is removed prior to closing the
mold halves together.
[0023] In accordance with still another aspect of the present
invention, an insole for use with footwear includes a first layer
having a lower shallow recess and a first set of properties such as
cushioning, hardness, density, resilience and/or color; and an
insert secured in the recess and being made of a material with a
second set of properties such as cushioning, hardness, density,
resilience and/or color, which may be different from the first set
of properties, the insert having an upper surface secured to the
first layer in the recess, and a peripheral portion of the upper
surface being free and unsecured to the first layer in the
recess.
[0024] Preferably, the first layer includes a forefoot portion
extending generally at least to the position of the metatarsals of
the foot; a heel portion; a mid portion connecting together the
forefoot portion and the heel portion; an upper surface extending
along the forefoot, mid and heel portions and on which a person
stands; and a lower surface extending along the forefoot, mid and
heel portions, the lower surface including the lower shallow
recess. The insert also preferably has a barrier layer on an upper
surface thereof to prevent a molding material from penetrating the
insert during a molding operation. However, the present invention
is not limited to full length insoles, but can be used with
three-quarter length insoles, foot pads, etc.
[0025] The above and other features of the invention will become
readily apparent from the following detailed description thereof
which is to be read in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a top plan view of a left shoe insole according to
the present invention;
[0027] FIG. 2 is a top plan view of a right shoe insole according
to the present invention;
[0028] FIG. 3 is a bottom plan view of the right insole of FIG.
2;
[0029] FIG. 4 is a bottom plan view of the left insole of FIG.
1;
[0030] FIG. 5 is a cross-sectional view of the left insole, taken
along line A-A of FIG. 1;
[0031] FIG. 6 is a cross-sectional view of the left insole, taken
along line B-B of FIG. 1;
[0032] FIG. 6A is a cross-sectional view of the left insole,
showing the barrier film;
[0033] FIG. 7 is a cross-sectional view of the left insole, taken
along line C-C of FIG. 1;
[0034] FIG. 8 is an exploded perspective view of apparatus for
making the insoles of FIGS. 1 and 2;
[0035] FIG. 9 is a perspective view of the bottom cavity mold of
the apparatus of FIG. 8;
[0036] FIG. 10 is a top plan view of the bottom cavity mold;
[0037] FIG. 11 is a cross-sectional view of the bottom cavity mold
of FIG. 10, taken along line D-D thereof;
[0038] FIG. 12 is a cross-sectional view of the bottom cavity mold
of FIG. 10, taken along line E-E thereof;
[0039] FIG. 12A is a cross-sectional view similar to FIG. 12, but
showing a modified embodiment of the present invention;
[0040] FIG. 12B is a cross-sectional view similar to FIG. 12, but
showing a further modified embodiment of the present invention;
[0041] FIG. 12C is a cross-sectional view similar to FIG. 12, but
showing a still further modified embodiment of the present
invention;
[0042] FIG. 13 is a front elevational view of the bottom cavity
mold;
[0043] FIG. 14 is a bottom perspective view of the top core mold of
the apparatus of FIG. 8;
[0044] FIG. 15 is a bottom plan view of the top core mold;
[0045] FIG. 16 is a side elevational view of the top core mold;
[0046] FIG. 17 is a top plan view of the adapter plate of the
apparatus of FIG. 8;
[0047] FIG. 18 is a top plan view of the base plate of the
apparatus of FIG. 8;
[0048] FIG. 19 is a top plan view of the lifter of the apparatus of
FIG. 8;
[0049] FIG. 20 is a cross-sectional view showing the insert trapped
between the lifter and lip;
[0050] FIG. 21 is an exploded perspective view of an alternative
apparatus for making the insole of FIG. 1, with a modified elevator
mechanism; and
[0051] FIG. 22 is a cross-sectional view of the apparatus of FIG.
21, showing the operation thereof.
DETAILED DESCRIPTION
[0052] The invention will be explained herein with reference to the
manufacture of shoe insoles, although those skilled in the art will
recognize that the equipment and method can advantageously be
applied to producing other insert molded products, and will be
particularly useful in any situation where flexible insert
materials are to be used.
[0053] Referring to the drawings in detail, and initially to FIGS.
1-7, a left insole 10 and a right insole 11 are shown, similar to
those which have been described in copending U.S. patent
application Ser. No. 09/476,642, filed on Dec. 31, 1999 and having
the same assignee herewith. The entire disclosure of said U.S.
patent application Ser. No. 09/476,642 is incorporated herein by
reference.
[0054] For clarity of description, the following discussion will
generally be limited to only left insole 10, it being readily
understood that the manufacture and properties of a right foot
insole are generally similar.
[0055] As shown, insole 10 has the shape of a human left foot and
therefore includes a curved toe or forefoot portion 12, a cupped
heel portion 14, and a mid portion 16 which connects forefoot
portion 12 and heel portion 14 together. Heel portion 14 generally,
but not always, will have a greater thickness than toe portion 12.
For example, heel portion 14 can have a thickness of about 4-8 mm,
while toe portion can have a thickness of about 1-6 mm.
[0056] Insole 10 is formed by a lower layer 18 and a top cover 20
secured to the upper surface of lower layer 18, along forefoot
portion 12, cupped heel portion 14 and mid portion 16, by any
suitable means, such as adhesives, radio frequency welding, etc.
Preferably, top cover 20 is secured to lower layer 18 when lower
layer 18 is molded in position, as will be explained in greater
detail hereinafter.
[0057] Lower layer 18 can be made from any suitable material
including, but not limited to, any flexible material which can
cushion and absorb the shock from heel strike on the insole.
Suitable shock absorbing materials can include any suitable foam,
such as, but not limited to, cross-linked polyethylene,
poly(ethylene-vinyl acetate), polyvinyl chloride, synthetic and
natural latex rubbers, neoprene, isoprene, block polymer elastomers
of the acrylonitrile-butadiene-styrene or styrene-butadiene-styrene
type, thermoplastic elastomers, ethylenepropylene rubbers, silicone
elastomers, polystyrene, polyureas or polyurethanes; more
preferably a polyurethane foam made from flexible polyol chains and
an isocyanate such as a monomeric or prepolymerized diisocyanate
based on 4,4'-diphenylmethane diisocyanate (MDI) or toluene
diisocyanate (TDI). Such foams can be blown with
chlorofluorocarbons, hydrofluorocarbons, water, methylene chloride
or other gas producing agents, as well as by mechanically frothing
to prepare the shock absorbing resilient layer. Such foams
advantageously can be molded into the desired shape or geometry.
Non-foam elastomers such as the class of materials known as
viscoelastic polymers, or silicone gels, which show high levels of
damping when tested by dynamic mechanical analysis performed in the
range of -50.degree. C. to 100.degree. C. may also be
advantageously employed. A resilient polyurethane can be prepared
from diisocyanate prepolymer, polyol, catalyst and stabilizers
which provide a waterblown polyurethane foam of the desired
physical attributes. Suitable diisocyanate prepolymer and polyol
components include polymeric MDI M-10 (CAS 9016-87-9) and Polymeric
MDI MM-103 (CAS 25686-28-6), both available from BASF, Parsippany,
N.J.; Pluracol 945 (CAS 9082-00-2) and Pluracol 1003, both
available from BASF, Parsippany, N.J.; Multrinol 9200, available
from Bayer, Pittsburgh, Pa.; MDI diisocyanate prepolymer XAS
10971.02 and polyol blend XUS 18021.00 available from the Dow
Chemical Company, Midland, Mich. These urethane systems generally
contain a surfactant, a blowing agent, and an ultra-violet
stabilizer and/or catalyst package. Suitable catalysts include
Dabco 33-LV (CAS 280-57-9,2526-71-8), Dabco X543 (CAS Trade
Secret), Dabco T-12 (CAS 77-58-7), and Dabco TAC (CAS 107-21-1) all
obtainable from Air Products Inc., Allentown, Pa.; Fomrez UL-38, a
stannous octoate, from the Witco Chemical Co., New York, N.Y.; or
A-1(CAS 3033-62-3) available from OSI Corp., Norcross, Ga. Suitable
stabilizers include Tinuvin 765 (CAS 41556-26-7), Tinuvin 328 (CAS
25973-55-1), Tinuvin 213 (CAS 104810-48-2), Irganox 1010 (CAS
6683-19-8), Irganox 245 (CAS 36443-68-2), all available from the
Ciba Geigy Corporation, Greensboro, N.C., or Givsorb UV-1 (CAS
057834-33-0) and Givsorb UV-2 (CAS 065816-20-8) from Givaudan
Corporation, Clifton, N.J. Suitable surfactants include DC-5169 (a
mixture), DC190 (CAS 68037-64-9). DC197 (CAS 69430-39-3) and
DC-5125 (CAS 68037-62-7) all available from Air Products Corp.,
Allentown, Pa. Alternatively, lower layer 18 can be a laminate
construction, that is, a multilayered composite of any of the above
materials. Multilayered composites are made from one or more of the
above materials such as a combination of polyethylene vinyl acetate
and polyethylene (two layers), a combination of polyurethane and
polyvinyl chloride (two layers) or a combination of ethylene
propylene rubber, polyurethane foam and ethylene vinyl acetate (3
layers).
[0058] Preferably, lower layer 18 is made from a urethane molded
material.
[0059] Note that, where available, Chemical Abstracts Service
("CAS") registration numbers have been provided for the various
chemical substances mentioned above.
[0060] Top cover 20 can be made from any suitable material
including, but not limited to, fabrics, leather, leatherboard,
expanded vinyl foam, flocked vinyl film, coagulated polyurethane,
latex foam on scrim, supported polyurethane foam, laminated
polyurethane film or in-mold coatings such as polyurethanes,
styrene-butadiene-rubber, acrylonitrile-butadiene, acrylonitrile
terpolymers and copolymers, vinyls, or other acrylics, as integral
top covers. Desirable characteristics of top cover 20 include good
durability, stability and visual appearance. It is also desirable
that top cover 20 has good flexibility, as indicated by a low
modulus, in order to be easily moldable. The bonding surface of top
cover 20 should provide an appropriate texture in order to achieve
a suitable mechanical bond to the upper surface of lower layer 18.
Preferably, the material of top cover 20 is a fabric, such as a
brushed knit laminate top cloth (brushed knit fabric/urethane
film/non-woven scrim cloth laminate) or a urethane knit laminate
top cloth. Preferably, top cover 20 is made from a polyester fabric
material.
[0061] Although the present invention has been used with top cover
20, the present invention does not require top cover 20.
[0062] According to the present invention, lower layer 18 is
prepared by open pour molding, followed by secondary die cutting or
in-mold die cutting.
[0063] During use, insole 10 is placed in a shoe so that the medial
side of mid portion 16 rests against the inside of the shoe.
Forefoot portion 12 may end just in front of the metatarsals.
However, insole 10 is preferably a full length insole, that is,
extends along the entire foot.
[0064] Typically, insole 10 would be sized corresponding to shoe
sizes and would be provided in sized pairs. According to prior U.S.
patent application Ser. No. 09/476,642, insole 10 is formed with a
structure to alleviate lower back pain and lower extremity pain.
Specifically, insole 10 is provided with a shallow recess 24 about
2 mm deep at the lower surface of lower section 18. An insert 26
having a thickness of about 2 mm and having the same shape as
shallow recess 24, is secured within shallow recess 24. Insert 26
is made from a softer or more cushioning material than the
remainder of lower section 18 of insole 10. For example, lower
section 18 of insole 10 can be made from a urethane foam having a
Shore "00" durometer hardness in the range of approximately 45-75,
more preferably in the range of approximately 55-65, and with a
preferred hardness of approximately 60, while insert 26 can be made
from a softer urethane foam having a Shore "00" durometer hardness
in the range of approximately 35-65, more preferably in the range
of approximately 45-55, and with a preferred hardness of
approximately 50. A preferred material for insert 26 is the
material sold by Rogers Corporation of Rogers, Conn. under the
trademark "PORON". However, other compressible and even
non-compressible materials can be used for insert 26, such as a
gel, elastomer, various composites, etc. As will be explained
hereinafter, insert 26 is formed first and then placed in a mold,
where the remainder of lower section 18 of insole 10 is molded
thereon, and thereby bonded to the PORON material of insert 26
during the molding operation.
[0065] Although the discussion of the present invention uses the
term "insole," it will be appreciated that the use of other
equivalent or similar terms such as "innersole" or "shoe insert"
are considered to be synonymous and interchangeable, and thereby
included within the present claimed invention. The term "insole" is
also intended to encompass other foot support and protection pads,
such as heel cups, arch supports, three-quarter length insoles and
heel pads.
[0066] As discussed above, there have been various problems with
forming insert 26 in insole 10, either with adhesive or in a
molding operation.
[0067] Accordingly, an apparatus 110 according to a first
embodiment of the present invention will now be described for
manufacturing insole 10 with insert 26 in a molding operation,
without the use of an adhesive, and which overcomes the
aforementioned problems.
[0068] As shown in FIGS. 8-12, apparatus 110 includes a bottom
cavity mold 112 having two lower mold cavities 114 therein shaped
to mold the lower halves of left and right shoe insoles 10. Bottom
cavity mold 112 includes a substantially flat raised sealing
surface 135 surrounding lower mold cavities 114. The sealing
surface 135 can be inclined or curved from the front to the rear
thereof. Each lower mold cavity 114 has side walls 118 that incline
downwardly from raised sealing surface 135.
[0069] According to an important aspect of the present invention,
an elevator opening 124 is formed in the lower surface of each
lower mold cavity 114 and has the outer peripheral shape and
dimensions of insert 26 to be placed in each lower mold cavity 114
of the mold during the molding operation. Elevator opening 124
includes an inwardly directed lip 126 at the upper end thereof, the
purpose for which will be understood from the discussion
hereinafter. The maximum size of lip 126 is determined by the ease
of de-molding and the extent to which the edge of insert 26 needs
to be attached to the insole. The minimum amount of the inward
extent of lip 126 is that which is required to create a proper
seal. As an example, lip 126 preferably extends inwardly for a
distance in the range of about 0.005 inch to 0.100 inch (0.12 to
2.54 mm), and more preferably 0.01 inch (0.25 mm). The greater the
inner extension of lip 126, the better lip 126 functions to hold
the flexible insert under lip 126 and maintain a seal against the
liquid urethane from flowing under the insert, that is, there is
less chance of overflow to the underside, but the harder it is to
remove the finished insole from the mold. Thus, the inner extension
distance of lip 126 will depend on the rigidity of the material of
insert 26, the pressure exerted by the liquid urethane inserted
into the mold and the difficulty of removing the finished insole
from the mold. As shown in FIG. 12, the portion of bottom cavity
mold 112 that connects to lip 126 increases in thickness away from
lip 126. This provides additional strength. However, the present
invention is not limited and such connection can be of uniform
thickness as well.
[0070] Although lip 126 is shown as being integrally connected with
bottom cavity mold 112, it is preferable that lip 126 be formed as
a removable member. In this regard, and referring to FIG. 12A, a
removable retainer 125 can be provided at elevator opening 124.
Removable retainer 125 includes a dam 127 flush with the vertical
wall of mold 112, the inside constituting elevator opening 124, a
lower outwardly extending connector 129 connected with the lower
end of dam 127 and which is secured to the lower surface of bottom
cavity mold 112 by bolts 131 and an inwardly extending lip 126'
connected to the upper end of dam 127. The reason for providing a
removable retainer 125 is that retainer 125 can be replaced in the
event of damage to lip 126', without changing the entire bottom
cavity mold 112. Further, with this arrangement, the height of lip
126' can be adjusted, for example, by using spacers between lower
connector 129 and the lower surface of bottom cavity mold 112.
Alternatively, to adjust the height of lip 126', retainer 125 can
be replaced by a new retainer having a different height of dam 127.
Alternatively, the lip length of lip 126' can be varied.
[0071] As a further way of adjusting the height of lip 126', dam
127 can be of a constant height, but the undersurface of bottom
cavity mold 112 can be cut away by different amounts at a position
where connector 129 attaches thereto, shown in FIGS. 12B and 12C.
By controlling the relative positioning of lip 126', as shown in
FIGS. 12A-12C, it can be controlled as to whether the lower surface
of insert 26 is flush with the molded urethane insole surface, as
in FIG. 12B, recessed relative thereto as shown in FIG. 12C or
protruding and raised from the insole surface as shown in FIG.
12A.
[0072] A top core mold 130 is provided above bottom cavity mold 112
for forming insole 10. Although the fastening is not shown, top
core mold 130 is preferably pivoted to bottom cavity mold 112.
Alternatively, bottom cavity mold 112 and top core mold 130 can be
connected with hydraulic or pneumatic cylinders for moving the two
apart and together, as is conventional in many molding
operations.
[0073] Top core mold 130 has two raised areas 132 at the lower
surface 133 thereof which are shaped and dimensioned to mold the
upper halves of left and right shoe insoles 10. Raised areas 132
are also shaped, dimensioned and positioned with respect to
corresponding lower mold cavities 114 so as to fit partially
therein and to define a mold cavity for molding insoles 10. The
lower surface 133 surrounding raised areas 132 is substantially
flat and can be inclined or curved from the front to the rear
thereof, to corresponding to flat raised sealing surface 135 of the
bottom cavity mold. Thus, when the mold is closed, lower surface
133 mates with raised peripheries of sealing surface 135 around
lower mold cavities to form a seal thereat and to form a closure
around the molded part cavity defined by lower mold cavities 114
and raised areas 132.
[0074] In accordance with the present invention, an elevator
mechanism 140 is housed in a base plate 142 below bottom cavity
mold 112. Specifically, elevator mechanism 140 includes two
cylinders 144. Although cylinders 144 are shown superimposed on
each other, this is only for simplicity in the drawing. Each
cylinder 144 is housed in a respective cylinder recess 146 in base
plate 142, corresponding to left and right insoles 10 to be molded.
Each cylinder 144 includes a piston rod 148 that can be extended
from the upper surface thereof. The upper end of each piston rod
148 is connected in a central opening 150 of an adapter plate 152.
Adapter plate 152, in turn, is connected in a cutaway portion
represented by area 154 between the broken lines in FIG. 19, but
present on the bottom of lifter 156, by means of bolts (not shown)
through openings 158 in adapter plate 152. Only one adapter plate
152 and one lifter 156 are shown for the sake of brevity in the
drawings, although it will be appreciated that there are two
adapter plates 152 and two lifters 156, one for each elevator
opening 124 in bottom cavity mold 112. Lifter 156 has the shape of
insert 26 to be provided in the mold during the molding operation.
In the lowered position of elevator mechanism 140, each lifter 156
fits within a respective cylindrical recess 146 and recess
extensions 160 thereof. In such position, in order to correctly
align lifters 156 in recess extensions 160, the lower surfaces of
lifters 156 are provided with downwardly extending posts 162 that
fit within openings 164 in recess extensions 160.
[0075] Lifters 156 fit within elevator openings 124 and are spaced,
prior to start of a molding operation, below the lower surfaces of
inwardly extending lips 126 by an amount equal to the thickness of
the inserts 26 to be supported thereby, plus a distance of about 1
mm. This additional distance permits inserts 26 to be easily loaded
and positioned on the upper surfaces of lifters 156 below lip
126.
[0076] In operation, top cover 20 is positioned to the lower
surface of top core mold 130. Piston rods 148 are lowered so as to
lower lifters 156 by a distance in the range of about 0.015 inch to
5 inches (0.38 to 130 mm), and more preferably in the range of
about 0.0625 inch to 0.5 inch (1.5 to 13 mm), and most preferably
about 0.4 inch (10 mm). This vertical distance depends on the
facility of positioning insert 26 in the mold, as well as removing
the finished insole from the mold. Then, inserts 26 are positioned
on lifters 156. Preferably, inserts 26 include a thin, such as
0.001 inch (0.025 mm), urethane barrier film 27 on the upper
surface thereof, as shown in FIG. 6A, to prevent migration of the
liquid urethane therethrough during the molding operation. Because
of the lowering of lifters 156 by about 1 mm, the upper surfaces of
inserts 26 are positioned about 1 mm from the lower surfaces of
lips 126. Then, weights (not shown), having the shape of but
slightly smaller than the outer periphery of elevator openings 124,
are placed through elevator openings 124 on top of inserts 26 to
hold inserts 26 flat. Without these weights, there is the
possibility that inserts 26 will not be held tightly along their
entire peripheries, providing a possibility that liquid urethane
can flow around the peripheral edges of inserts 26.
[0077] Alternatively, pressure can be applied to the top of the
insert by an external robotic arm or an equivalent thereof to hold
the insert flat, until the lifter 156 is raised and the insert is
sealed on its periphery between the top of the lifter and the lip
126.
[0078] Elevator mechanism 140 is then raised. Specifically, piston
rods 148 are raised so as to raise lifters 156 until the outer
edges of inserts 26 are clamped or pinched between the top surfaces
of lifters 156 and lips 126. As a result, a seal is provided
thereat. The weights or robot supplied pressure are then removed
from inserts 26. Because of the seal provided by lips 126, during
the mold filling activity there is no flow of liquid urethane
around the peripheral edges of inserts 26.
[0079] At this time, a top cover 20 is secured to the lower surface
of top core mold 130. Then, liquid urethane is poured into the
bottom cavity mold 112 and/or top core mold 130, as is
conventional. Top core mold 130 and bottom cavity mold 112 are then
brought together to define the mold cavity. In such case, raised
peripheries 135 of bottom cavity mold 112 and lower surface 133 of
top core mold 130 form a sealing arrangement. The mold dimensions
and/or retainers 125 are used to adjust the height of inserts 26.
Thus, for example, inserts 26 can be adjusted to be raised, flush
or recessed, as shown in FIGS. 12A-12C. In addition, the pressure
applied by lifters 156 against lips 126 can be such as to just hold
inserts 26 in place or can be such as to compress the peripheral
edges of inserts 26. Generally, insert 26 is just held in place to
its exact thickness where insert 26 is not readily
compressible.
[0080] At the closing of the mold halves, the liquid urethane
begins to expand and fills the mold, generating high internal
cavity pressures. Thus, it is necessary that cylinders 144 provide
sufficient pressure to overcome the internal molding pressures
acting on lifters 156 to remain raised and level or the lifters
must be locked in the sealed position during molding. The liquid
urethane thereafter cures to form the finished insoles 10. However,
at this time, lips 126 are positioned above the peripheral edges of
inserts 26, that is, in a gap 35 between inserts 26 and the
remainder of insoles 10. Therefore, when opening the mold halves,
lips 126 must be pulled out of this gap 35. Inserts 26 must be
sufficiently flexible to permit the molded material to be pulled
out of lips 126, that is, inserts 26 cannot be too rigid. For this
reason, although inserts 26 can be non-compressible, they still
must be sufficiently flexible to remove them from the mold.
[0081] Just before the mold halves open, lifters 156 are lowered to
release flexible inserts 26 from the clamping arrangement with lips
126. Then, the mold halves are opened. The molded assembly of the
two insoles 10 is pulled off top core mold 130 as it opens because
inserts 26 are held by lips 126. The molded assembly is then pulled
away from bottom cavity mold 112 and lips 126, and trimmed to form
left and right insoles 10.
[0082] As shown in FIGS. 5-7 and 6A, because of the thickness of
lips 126, there is a small gap 35 between the sides of inserts 26
and the lower layer 18 of insole 10. Further, a peripheral portion
of the upper surface of insert 26 is free and unsecured to first
layer 18 in recess 24 due to lips 126 and resulting gap 35, as
shown best in FIG. 6A.
[0083] Thus, with the present invention, there is no staining of
the inserts, either at the periphery due to overflow or otherwise
due to penetration of the liquid urethane into the inserts. The
prevention of the overflow around the periphery is due to the
elevator mechanism 140 and lips 126, which seals the insert edges,
preventing flow of the liquid urethane around the peripheral edge
of the inserts. Further, elevator mechanism 140 permits inserts 26
to be inserted under lips 126 and thereafter clamps the peripheral
edges of inserts 26 between lifters 156 of elevator mechanism 140
and lips 126. In addition to preventing flow around the periphery
of inserts 26, barrier layer 27 on each insert 26 prevents
penetration of the liquid urethane into and through inserts 26
during the molding operation which would otherwise cause the
staining.
[0084] Although elevator mechanism has been shown as using
cylinders 144 and piston rods 148 for controlling movement of
lifters 156, any other suitable elevator mechanism can be used,
which can withstand the pressure of the molding operation. In this
regard, reference is now made to FIGS. 21 and 22 for an alternative
elevator mechanism 140' in which elements that are common to the
first embodiment of FIGS. 8-20 are identified by the same reference
numerals.
[0085] Specifically, downwardly extending posts 162 of lifters 156
are fixed in openings 200 of two parallel, spaced apart, elongated
rectangular upper slide plates 202 in fixed relation to each other
corresponding to elevator openings 124. Two spaced apart, inclined
upper cam surfaces 204 are fixed to the lower surfaces of each
upper slide plate 202. In like manner, two parallel, spaced apart,
elongated rectangular lower slide plates 206 are provided in
alignment with and directly below upper slide plates 202. Two
spaced apart, inclined lower cam surfaces 208 are fixed to the
upper surfaces of lower slide plates 206, such that inclined upper
cam surfaces 204 rest on inclined lower cam surfaces 208.
[0086] Base plate 142' is provided with two parallel, spaced apart,
elongated rectangular deep recesses 210, each housing upper and
lower slide plates 202 and 206 so as to permit sliding movement in
the longitudinal direction thereof. The raised portion 211 of base
plate 142' between recesses 210 is provided with two shallow
recesses 213 which are arranged generally perpendicular to deep
recesses 210 and which are shaped and dimensioned to receive
lifters 156.
[0087] A lever mechanism 212 is provided to raise lifters 156.
Lever mechanism 212 includes a block 214 secured to a side surface
of raised portion 211 of base plate 142' between one end of deep
recesses 210. An L-shaped lever 216 is pivotally mounted to block
214 by a pivot pin 218. The lower leg 216a of lever 216 is
pivotally mounted to a plate 220 by a pivot pin 222. The opposite
ends of plate 220 are connected to lower slide plates 206.
[0088] In operation, as the upper leg 216b of lever 216 is pushed
up in FIG. 22 so as to pivot lever 216 in the clockwise direction,
plate 220 moves away from base plate 142'. As a result, lower slide
plates 206 are pulled slightly out of deep recesses 210. Because of
this movement, upper cam surfaces 204 ride up on lower cam surfaces
208, resulting in raising of lifters 156. Because lifters 156 are
constrained within elevator openings 124, lifters 156 can only move
in a vertical direction.
[0089] Other suitable elevator mechanisms can also be provided, for
example, screw arrangements, rack and pinion arrangements, and the
like.
[0090] Further, although lip 126 has been described as being
stationary, with lifters 156 being raised and lowered, it is
possible within the context of the present invention to move lips
126 up and down and keep lifters 156 stationary, or to relatively
move both lips 126 and lifters 156 up and down.
[0091] It will be appreciated that modifications can be made to the
present invention within the scope of the claims. For example,
while the elevator opening and elevator mechanism have been
described in relation to lower cavity mold 112, the elevator
opening and elevator mechanism can be provided in addition to, or
alternatively with, top core mold 130.
[0092] From this description of specific preferred embodiments, it
will be appreciated that the present invention is not limited to
those precise embodiments and that various changes and
modifications can be effected by one of ordinary skill in the art
without departing from the scope or spirit of the invention as
defined by the appended claims.
* * * * *