U.S. patent number 3,806,974 [Application Number 05/216,610] was granted by the patent office on 1974-04-30 for process of making footwear.
Invention is credited to Anthony George Di Paolo.
United States Patent |
3,806,974 |
Di Paolo |
April 30, 1974 |
PROCESS OF MAKING FOOTWEAR
Abstract
The invention disclosed is directed to skid-resistant footwear
having an outer sole provided with grooves and wavy ribs spaced
apart by the grooves. Also disclosed is an improved process for
making the footwear, including injection molding a bottom onto a
footwear upper employing a mold with a bottom plate having wavy
elongate uprights.
Inventors: |
Di Paolo; Anthony George (New
York, NY) |
Family
ID: |
22807758 |
Appl.
No.: |
05/216,610 |
Filed: |
January 10, 1972 |
Current U.S.
Class: |
12/142RS |
Current CPC
Class: |
A43B
13/223 (20130101); B29D 35/081 (20130101) |
Current International
Class: |
A43B
13/14 (20060101); A43B 13/22 (20060101); B29D
31/50 (20060101); B29D 31/51 (20060101); A43d
009/00 () |
Field of
Search: |
;12/142R,142RS,142E
;36/32R,3R |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Lawson; Patrick D.
Attorney, Agent or Firm: Harness; Charles L.
Claims
What is claimed is:
1. In a process for making footwear having a molded bottom attached
to an upper, said process including:
a. providing a partial mold assembly having side mold means and a
sole plate within the side mold means, said side mold means having
an inner peripheral recess corresponding substantially in height to
the height of the bumper portion of the bottom to be formed, with
the side mold means and the sole plate defining an upwardly open
hollow space;
b. inserting a last-and-upper assembly into the hollow space, said
last-and-upper assembly including a last and a footwear upper
demountably mounted on the last, with the bottom of the upper
extending inwardly under at least the bottom edge of the last, to
engage the side mold means and to provide a molding arrangement
having a cavity defined by the lower portion of the lasted-upper
assembly, the side mold means, and the sole plate, said molding
arrangement having channel means connected to said cavity for
injection filling the cavity with a solid forming liquid
material;
c. injecting elastomeric solid forming liquid material through the
channel means to substantially fill the cavity in the molding
arrangement; and
d. permitting the injected liquid material to solidify to form a
bottom attached to the upper;
the improvement which comprises using a sole plate having a
multiplicity of spaced apart elongage uprights extending
transversely of the longitudinal axis of the sole plate in
generally parallel wavy relationship one to the others, with
thickness of the uprights being from about 0.05 to about 1
millimeter longitudinally of the sole plate and the spacing between
the uprights to the height of the uprights being from about 0.8 to
about 5.
2. The process of claim 1 wherein the thickness of the uprights is
from about 0.2 to about 0.3 millimeter longitudinally of the sole
plate.
3. The process of claim 1 wherein the tops of the uprights are
above the sole plate surface across which the uprights extend by
from about 2 to about 5 millimeters.
4. The improved process of claim 1 wherein the uprights are of
generally rectangular U-shape in vertical section longitudinally of
the sole plate.
5. The process of claim 1 wherein said uprights are from about 0.1
to about 0.3 millimeter in thickness longitudinally of the sole
plate and from about 2 to about 3 millimeters in height, the
distance between the uprights being from about 2 to about 3
millimeters.
6. The process of claim 1 wherein the sole plate surface is
arcuately tapered longitudinally upwardly from about the middle of
the surface to within one inch of the toe end and is of
transversely arcuate upwardly concave shape in said longitudinally
arcuate portion.
7. The process of claim 1 wherein the improvement further includes
lasting the upper such that the bottom of the upper tapers inwardly
and slightly downwardly away from the last.
8. In a process for making footwear having a molded multipart
bottom attached to an upper, said process including;
a. providing a partial mold assembly having side mold means and a
movable sole plate within the side mold means, said mold means
having an inner peripheral recess corresponding substantially in
height to the height of the bumper portion of the bottom to be
formed, with the side mold means and the sole plate defining an
upwardly open hollow space;
b. inserting a last-and-upper assembly into the hollow space to
engage the side mold means, said last-and-upper assembly including
a last and a footwear upper demountably mounted on the last, with
the bottom of the upper extending inwardly under at least the outer
portion of the bottom of the last;
c. moving the sole plate to a first position characterized in that
the bottom edge of said recess is below the shoulder of said plate
to provide a mold having a first cavity defined by the lower
portion of the last-and-upper assembly, the side mold means, and
the sole plate;
d. injecting elastomeric solid-forming liquid material to
substantially fill the first cavity in the mold;
e. maintaining the plate in said first position until the injected
material solidifies substantially throughout to form a first sole
attached to the upper and having a bumper portion peripherally of
its inner portion;
f. providing a second cavity by lowering the sole plate to a second
position characterized in that the bottom edge of said recess is
slightly above the shoulder of the plate;
g. injecting solid-forming liquid material to substantially fill
the second cavity; and
h. maintaining said plate in the second position until the liquid
material injected in part (g) solidifies substantially throughout
to form a lower sole attached to said first sole;
the improvement which comprises using a sole plate having a
multiplicity of spaced apart elongate uprights extending
transversely of the longitudinal axis of the sole plate in
generally parallel wavy relationship one to others, with thickness
of the uprights being from about 0.05 to about 1 millimeter
longitudinally of the sole plate.
9. The process of claim 8 wherein the sole plate includes margins
between the opposite ends of said uprights and the sole plate
periphery.
10. In a process for making footwear having a molded bottom
attached to an upper, said process including:
a. providing a partial mold assembly having side mold means and a
sole plate within the side mold means, said side mold means having
an inner peripheral recess corresponding substantially in height to
the height of the bumper portion of the bottom to be formed, with
the side mold means and the sole plate defining an upwardly open
hollow space;
b. inserting a last-and-upper assembly into the hollow space, said
last-and-upper assembly including a last and a footwear upper
demountably mounted on the last, with the bottom of the upper
extending inwardly under at least the bottom edge of the last, to
engage the side mold means and to provide a molding arrangement
having a cavity defined by the lower portion of the lasted-upper
assembly, the side mold means, and the sole plate, said molding
arrangement having channel means connected to said cavity for
injection filling the cavity with a solid forming liquid
material;
c. injecting elastomeric solid-forming liquid material through the
channel means to substantially fill the cavity in the molding
arrangement; and
d. permitting the injected liquid material to solidify to form a
bottom attached to the upper;
the improvement which comprises using a sole plate having a
multiplicity of spaced apart elongate uprights extending
transversely of the longitudinal axis of the sole plate in
generally parallel wavy relationship one to the others, with
thickness of the uprights being from about 0.05 to about 1
millimeter longitudinally of the sole plate, said uprights having
first arcuate side portions facing in a first direction and
connected by oppositely facing arcuate side portions, the average
radius of the first arcuate portions being relatively smaller than
the average radius of the oppositely facing arcuate portions.
Description
The present invention relates to footwear of improved skid
resistance having an outer sole provided with grooves and wavy ribs
spaced apart by the grooves. The invention also provides
improvements in footwear-making processes of the type which include
forming and attaching a bottom to an upper by injection molding.
The improvements include forming the bottom using a bottom plate
having wavy elongate uprights for providing the grooves and ribs in
the outer sole.
Numerous methods for forming footwear are available to the art.
Generally, however, footwear forming methods known heretofore have
not been entirely satisfactory for reasons such as complexity,
inefficiency and others. Designs for soles of footwear or shoes are
taught in U. S. Pat. D 117,585 to Sperry and in U. S. Pat. D
196,355 to Doherty. Soles provided with the Sperry U.S. Pat. D
117,585 design include zigzag slits in a smooth surface thereof and
are characterized when at rest in that sections formed between the
slits are in contact. It is a standard procedure in the shoe making
industry to cut or punch slits in sole blanks and cut the slit
blanks to prepare soles. However, the procedure has a number of
drawbacks in that sensitive devices which form the slits are easily
damaged and cutting soles from blanks typically results in waste of
residual blank materials. Attaching the prepared sole to footwear
undesirably requires great skill and care which, when not
exercised, often result in formation of low quality footwear
referred to in the art as rejects. In general, soles having the
U.S. Pat. D 117,585 design have not been entirely satisfactory from
not only the standpoint of skid resistance, but also from
standpoints of efficiency in forming such soles and in making
footwear employing the soles.
Soles of the Doherty U. S. Pat. D 196,355 design include a tread
layer of complex tapering construction which provides less than the
amount of ordinarily supportable tread surface desired by many
wearers. Footwear provided with soles of such designs are of
further limited utility in that the soles are difficult to clean
and when the soles are pressed by the weight of a wearer against
non-rigid supports, such as soft carpets and others, objectionable
indentations result in the supports. Moreover, mud and other soils,
particularly when wet, tend to cake in the acutely tapering
recesses of such soles and after drying, such caking often is
undesirably released.
Footwear having a molded bottom attached to an upper is well known
in the art. It is conventional to make such footwear using
processes of the type which include, in general, steps
substantially as follows:
A. providing a partial mold assembly having side mold means and a
sole plate within the side mold means, said side mold means having
an inner peripheral recess corresponding substantially in height to
the height of the bumper portion of the bottom to be formed, with
the side mold means and the sole plate defining an upwardly open
hollow space;
B. inserting a last-and-upper assembly into the hollow space, said
last-and-upper assembly including a last and a footwear upper
demountably mounted on the last, with the bottom of the upper
extending inwardly under at least the bottom edge of the last, to
engage the side mold means and to provide a molding arrangement
having a cavity defined by the lower portion of the lasted-upper
assembly, the side mold means, and the sole plate, said molding
arrangement having channel means connected to said cavity for
injection filling the cavity with a solid-forming liquid
material;
c. injecting elastomeric solid-forming liquid material through the
channel means to substantially fill the cavity in the molding
arrangement; and
d. permitting the injected liquid material to solidify to form a
bottom attached to the upper.
Variations in the process are taught, for example, in U. S. Pat.
No. 3,345,664 to Ludwig; U. S. Pat. No. 3,372,415 to King; U. S.
Pat. No. 3,345,763 to Rollman; and in U. S. Pat. No. 3,510,968 to
Hobbs et al.
It has now been found by practice of the present invention that
footwear having a skid-resistant outer sole provided with grooves
and wavy ribs spaced apart by the grooves is made in simple,
economical manner. Such footwear may be made in accordance with
this invention using minimum hand labor, thus overcoming numerous
drawbacks of the prior art. Typically, more than half the labor
involved in conventional footwear-forming methods may thus be
eliminated.
Generally stated, the present invention provides improvements in
conventional footwear-making processes of the type which is
generally set forth above. The improvements include using in
processes of the foregoing type a sole plate having a multiplicity
of spaced apart elongate uprights extending transversely of the
longitudinal axis of the sole plate in generally parallel wavy
relationship one to others, with thickness of the uprights being
from about 0.05 to about 1 millimeter longitudinally of the sole
plate. When made by the improved process of this invention, the
present footwear may be characterized with better resistance to
skidding without detracting from wear resistance thereof and
without sacrificing foot comfort.
Practice of the present invention will become more apparent from
the following detailed description taken in conjunction with the
accompanying drawings wherein like numerals refer to similar
elements throughout the several views.
In the drawings:
FIG. 1 is an elevation view longitudinally of a shoe having a
molded bottom generally illustrating footwear of the present
invention;
FIG. 2 is a plan view of the shoe of FIG. 1 illustrating the
groove-containing outer sole thereof;
FIG. 3 is a longitudinal section of the shoe taken on line 3--3 of
FIG. 2, with part of the upper removed;
FIG. 4 is a transverse section of the shoe illustrated in FIG. 1
taken on line 4--4 thereof;
FIG. 5 is a transverse section of the shoe of FIG. 1 taken on line
5--5 thereof;
FIG. 6 is an enlarged plan view of the part of the bottom within
broken rectangular line 6 of FIG. 2 showing part of the outer sole
in greater detail;
FIG. 7 is an enlarged longitudinal section taken on line 7--7 of
FIG. 2 and FIG. 6;
FIG. 8 is an enlarged transverse section taken on line 8--8 of FIG.
2 and FIG. 6;
FIG. 9 is an enlarged transverse section taken on line 9--9 of FIG.
2 and FIG. 6;
FIG. 10 is an elevation section longitudinally of a molding
arrangement for making footwear having a multiple groove-containing
outer sole according to the improved process of this invention,
illustrating the sole plate employed, with the sole plate in a
position for forming an upper sole;
FIG. 11 illustrates, in sectional view resembling FIG. 10, an upper
sole formed according to the process;
FIG. 12 is a view showing the molding arrangement after lowering
the sole plate to a position for injecting outer sole material;
FIG. 13 is a sectional view similar to FIG. 12, illustrating an
outer sole formed according to the process;
FIG. 14 is an elevation section transversely of the molding
arrangement prior to injecting material to form the upper sole;
FIG. 15 is a sectional view similar to FIG. 14, illustrating a shoe
bottom made using the process;
FIG. 16 is an enlarged fragmentary section of the mold illustrating
the shoulder portion of an embodiment lasted upper; and
FIG. 17 illustrates, in a view resembling FIG. 16, embodiment
footwear with the upper more deeply embedded in the upper sole.
Footwear made according to the improved process of this invention
is illustrated by shoe 10 shown in an elevation view in FIG. 1, in
a bottom plan view in FIG. 2 and in longitudinal elevational
section in FIG. 3. The shoe includes upper 11 of suitable flexible
material to which is attached bottom part 12 which includes outer
sole 14 connected to the upper by bumper portion 16 which is
peripheral of the bottom and integral with inner portion 24 of
upper sole 18 (FIG. 3). As shown in FIG. 2 generally, and more
fully described herein below, the bottom includes a number of wavy
ribs 26 which are spaced apart by a multiplicity of elongate
grooves 28 extending transversely of the longitudinal axis of the
shoe in generally parallel wavy relationship one to others. The
grooves must be from about 0.05 to 1 millimeter in thickness,
measured longitudinally of the bottom part. The outer sole may
include margins 30 and 31 between opposite ends of the grooves and
the bumper portion.
Details in the construction of the shoe are more clearly
illustrated by the sectional views shown in FIGS. 3, 4 and 5, which
are taken along lines 3--3, 4--4 and 5--5 respectively (FIGS. 1 and
2). The bumper or edge portion includes midpart 19 with ridge 20
projecting upwardly from the midpart and fitting tightly about
upper 11 in outwardly facing portions of the lower shoulder
thereof. The bumper includes lower portion 22 which projects
downwardly from the midpart and contains the outer or tread sole
14. The lower shoulder of the upper includes shelf 25 extending
inwardly of the bumper with lasting string 27 attached to the edge
of the shelf by stitching not shown. The topside of inner portion
24 of the upper sole may be concavely arcuate transversely of the
shoe, as generally shown in the transverse sectional elevation
views of FIG. 4 and FIG. 5. Generally, concave upper soles provide
greater comfort to the feet of wearers.
The ribs and grooves provided in the outer sole of footwear made
according to this invention are illustrated in greater detail in
FIGS. 6-9. Generally, the grooves must be from about 0.05 to about
1 millimeter in thickness, measured longitudinally of the outer
sole. It is found that grooves which are larger than about 1
millimeter in thickness trap objects causing discomfort or
annoyance to the wearer, while grooves which are smaller in
thickness generally fail to provide adequate skid resistance to the
shoe. The grooves preferably are in the range from about 0.2 to
about 0.3 millimeter in thickness. The inner portion of the upper
sole may be of a foam material. The bumper portion and the tread
surface of the outer or lower sole are preferably of dense
wear-resistant elastomeric material. The grooves in the outer sole
permit flexing of the ribs and reflexing to non-biased position,
and are generally found to aid in minimizing wear of the sole tread
surface.
As a general preference, the grooves are of generally rectangular
U-shape in vertical section longitudinally of the shoe. It is found
that grooves of such shape normally resist clogging with mud or
other soils and at least do not uncontrolably release such soils in
the event that clogging does obtain, thereby increasing the
versatility of the shoe with respect to where it may be suitably
worn. It is also generally found that grooves of thin rectangular
shape provide good balance between anti-caking and receptivity to
water such that good traction is provided on slippery surfaces, for
example, on boats where water often collects in slip producing
manner. The present shoe is thus eminently suitable for use by
wearers even on surfaces of boats and other slippery surfaces.
In a preferred embodiment, the curvature of the grooves bears a
relationship to the thickness thereof such that the ribs provided
in the sole are solid in transverse vertical section taken, as at
line 8--8 (and shown in FIG. 8) forwardly of the foremost parts of
the rear face of a rib and rearwardly of the rearmost parts of the
forward face of the same rib. As used herein, the words "forward,"
"forwardly" and "foremost" refer to the forward or toe end of the
sole (or the direction thereof), the location of which is indicated
in FIG. 6 by directional arrow 32; and the terms "rearward,"
"rearwardly" and "rearmost" refer to the opposite or heel end of
the sole (or the direction thereof), the location of which is
indicated by directional arrow 34.
The sides of the various grooves which appear as wavy lines
transversely of the sole in the plan view of FIG. 6 include a
plurality of spaced apart arcuate toewardly convex portions and a
plurality of spaced apart arcuate toewardly concave portions,
generally as illustrated, with the convex portions connected one to
others in repeated manner by the concave portions and with the
concave portions connected one to others in repeated manner by the
convex portions. It is unexpectedly found that skid resistance is
further improved by providing grooves having sides characterized in
that the average radius r of the arcuate side portions which face
in a first direction is relatively small with respect to the
average radius R of the arcuate portions facing in the opposite
direction as shown in FIG. 6.
While the grooves may be of almost any depth, groove depth of about
2 to about 5 millimeters is found suitable. Flexibility of the ribs
is dependent on the material of which the lower sole is formed. In
general, however, suitable flexibility is provided by ribs having
longitudinal thickness corresponding to from about 0.8 to about 2
times the depth of the grooves. A sole which is generally preferred
includes, in combination, ribs having longitudinal thickness from
about 2 to about 3 millimeters and grooves having longitudinal
thickness of about 0.1 to about 0.3 millimeter and depth of about 2
to about 3 millimeters. In general, ribs corresponding in thickness
to more than about 5 times the depth of the grooves are
insufficiently flexible to provide adequate skid resistance.
As used herein, the term "elastomer" means any and all plastics or
plastic-like materials embodying characteristics of resiliency and
capability of being rendered plastic for a sufficient length of
time to be injected into a mold to form the bottom part of a shoe
and to be then caused to set, cure, harden, solidify or otherwise
become relatively dimensionally stable. Suitable solid-forming
liquid materials which may be used to form the bottom of the shoe
are exemplified by, but not limited to, polyvinyl chloride
mixtures, rubber, polyurethane mixtures and the like.
Referring to FIGS. 10-15, the present process for making footwear,
illustrated by shoe 10, includes providing a mold assembly having
side mold means, illustrated by split ring side molds 36, and sole
plate 38. In accordance with this invention, the sole plate has a
multiplicity of wavy elongate uprights 40 extending transversely of
the longitudinal axis of the plate in generally parallel
relationship one to others for providing grooves 28 in shoe 10. The
thickness of the uprights generally must be from about 0.05 to
about 1 millimeter longitudinally of the sole plate. It is found
that uprights which are more than on one millimeter in thickness
form unsuitably thick grooves in outer soles, while uprights which
are less than 0.05 millimeter in thickness are of inadequate damage
resistance for economical use thereof. For greater protection
against these and other undesirable results, the uprights
preferably are of thickness in the range of from about 0.2 to about
0.3 millimeter. Split ring side mold 36 includes inner peripheral
recess 42 corresponding substantially in height to the height of
the bumper portion of the bottom to be formed, with the side mold
and the sole plate defining an upwardly open hollow space. The side
mold includes lip 43 above recess 42 for engagement with a lasted
upper inserted into the hollow space. A lasted upper assembly
including upper 11 lasted about last 54 is inserted into the mold
space to form a molding arrangement wherein the lasted upper is in
engagement with mold lip 43 and having cavity 45 (FIG. 10) defined
by the lower portion of the lasted upper assembly, the side mold,
and the sole plate. The molding arrangement is provided with means
for injection filling cavity 45 as illustrated by passage 44 which
connects recess 42 to the outer edge of the side mold and may have
a tapered end for receiving an outlet nozzle of an injection
extruder. Sole plate 38 may be provided with means for injecting
elastomeric material as illustrated by passage 46 having a first
port 48 in plate surface 49 and a second port 50 for flow
communication with passage 52 provided in the side mold (FIGS. 12
and 13).
The lasted upper assembly may be any suitable arrangement of an
upper on a last, examples of which include Mackay lasted uppers,
vertical welt and string lasted uppers, and lasted uppers with
sewn-in upper soles for contacting the foot of a wearer.
Elastomeric solid-forming liquid material is injected as through
passage 44 to substantially fill the cavity 45 (FIGS. 10 and 14)
while the sole plate is in a first position characterized in that
bottom edge 53 of the recess in the side mold is below the shoulder
of the sole plate as shown in FIGS. 10, 11 and 14. The sole plate
is maintained in the first position until the injected material
solidifies or hardens substantially throughout to form upper sole
18 attached to the upper and having bumper portion 16 peripherally
of inner portion 24 of the upper sole as shown in FIG. 11. It is
found that sole plates formed of aluminum or alloys thereof or
almost any material of thermal conductivity on the order of that of
aluminum reduce the time for solidification to take place. Uprights
40 are found to aid in minimizing solidification time. The plate
may be provided with additional means for cooling such as holes
(not shown) with cooling water circulated therethrough.
After upper sole 18 sets or solidifies to form a dimensionally
stable structure, the sole plate is lowered to a second position
characterized in that the bottom edge of the recess is slightly
above the shoulder of the plate, thus providing cavity 47 within
downwardly projecting portion 22 of the bumper 16 as shown in FIG.
12. Cavity 47 may then be filled by injecting solid-forming liquid
material through passage 52, port 50, passage 46 and port 48 in
sufficient amount to at least substantially fill the cavity. The
plate is maintained in the second position for a suitable time to
permit setting or solidification of the injected material,
resulting in formation and bonding of groove-containing outer sole
14 to upper sole 18 as shown in FIGS. 13 and 15. The mold is
thereafter opened as by retracting a half-ring of the side mold to
permit removal of the molded bottom shoe which may be demounted
from the last in any suitable manner. Residual injection molding
material may be withdrawn from the various passages in any suitable
manner as by means of sprue extractor apparatus disclosed in U. S.
Pat. No. 3,588,958 to Metzger.
The sole plate may have upright-free margins between the opposite
ends of the uprights and the peripheral edge of the sole plate, the
sole plate margins corresponding to margins 30 and 31 of the outer
sole as shown in FIG. 2. It is found that sole plates having
margins provide longer and more efficient service with less
accidental damage to the uprights.
In footwear made by the above-described two-step injection
embodiment of the present improved process and illustrated by shoe
10, wavy elongate projections 56 of the outer sole 14 are tightly
received in corresponding grooves 58 in the upper sole, thereby
providing added strength to the bond. The two-step injection
process has the added advantage that different plastic compositions
may be used for the upper sole and for the outer sole. The
different compositions may also differ in color, thereby providing
greater versatility.
Optionally, outer sole 14 and upper sole 18 may be formed of one
piece construction in a one-step injection operation in which the
sole plate is initially placed in the second position, i.e.,
omitting the first plate position and injecting solid-forming
liquid material into the resulting cavity.
While the bottom of the outer sole may have any suitable shape, it
is found that generally better skid resistance and increased bottom
durability are provided by a preferred embodiment of the present
process using a sole plate with the sole plate surface 49 arcuately
tapering longitudinally upwardly from generally about the middle of
the sole plate or slightly forward thereof to within a one inch
region near the toe end in a manner corresponding generally to
longitudinally arcuate forward portion 15 of the outer sole as
illustrated in FIG. 1. The forward portion of the outer sole may be
formed of transversely arcuate upwardly concave shape as shown in
FIG. 4 by molding with a sole plate the forward portion of which is
transversely arcuate as shown in FIG. 15.
Sole plates for use herein may be formed using any suitable forming
method. For example, the sole plate may be made from an appropriate
piece of metal stock, preferably aluminum or aluminum alloy stock,
using conventional milling techniques.
The shape of the uprights provided on the sole plate should be
substantially the same as the shape of the grooves to be provided
in the outer sole being formed. Thus, as a general preference, the
uprights are generally of rectangular U-shape in vertical section
longitudinally of the sole plate. The tops of the uprights may
suitably be above the sole plate surface across which the uprights
extend by from about 2 to about 5 millimeters. Spacing between the
uprights may be from about 0.8 to about 2 times the height of the
uprights. A generally preferred shoe is made using a sole plate
with uprights spaced apart at a distance from about 2 to about 3
millimeters, the uprights being from about 0.1 to about 0.3
millimeter in thickness longitudinally of the sole plate and from
about 2 to about 3 millimeters in height as measured between the
tops of the uprights and the sole plate surface across which the
uprights extend. The uprights may have sides characterized in that
the average radius of arcuate side portions facing in a first
direction is small relative to the average radius of oppositely
facing side portions, corresponding to the grooves illustrated in
FIG. 6. Where sole plate margins corresponding to outer sole
margins 30 and 31 are included, they preferably are at least about
one millimeter in width transversely of the sole plate.
The enlarged fragmentary view of FIG. 16 (corresponding to a
portion of FIG. 14) and the enlarged fragmentary view shown in FIG.
17 (corresponding to a portion of FIG. 15) show an arrangement of
the upper on the last in another embodiment of this process. It is
seen that the lower margin or shelf 25 of the upper may be drawn by
string 27 to a position tapering inwardly and slightly downwardly
away from last 54. Upon injection molding in the foregoing manner,
this embodiment results in further embedding the shelf and string
in the molded bottom and thus provides a smoother foot contacting
surface to the added comfort of the wearer.
It is to be understood that the foregoing detailed description is
given merely by way of illustration and that various modifications
may be made therein, including in the improvements provided by the
present invention and in the basic heretofore known process,
without departing from the spirit or scope of the present
invention.
* * * * *