U.S. patent number 3,758,903 [Application Number 05/277,884] was granted by the patent office on 1973-09-18 for method and apparatus for unit molding.
This patent grant is currently assigned to Ro-Search, Incorporated. Invention is credited to Horace Ray Auberry, Anton I. Liebscher.
United States Patent |
3,758,903 |
Auberry , et al. |
September 18, 1973 |
METHOD AND APPARATUS FOR UNIT MOLDING
Abstract
A method of lasting shoe uppers and sole-attaching devices to
carry out the method.
Inventors: |
Auberry; Horace Ray (Tuscola
Park, NC), Liebscher; Anton I. (Waynesville, NC) |
Assignee: |
Ro-Search, Incorporated
(Waynesville, NC)
|
Family
ID: |
23062785 |
Appl.
No.: |
05/277,884 |
Filed: |
August 4, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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78412 |
Oct 6, 1970 |
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Current U.S.
Class: |
12/142RS;
12/1A |
Current CPC
Class: |
B29D
35/061 (20130101); B29D 35/065 (20130101) |
Current International
Class: |
B29D
31/50 (20060101); B29D 31/508 (20060101); A43d
009/00 () |
Field of
Search: |
;12/142R,142RS,1A,1R,36,37 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lawson; Patrick D.
Parent Case Text
This application is a continuation-in-part of our copending
application Ser. No. 78,412, filed Oct. 6, 1970.
Claims
What is claimed is:
1. The method of manufacture of footwear which includes the steps,
in sequence, of placing an upper upon a last, positioning a
sideframe in proper position relative to the upper and last to hold
the upper in its proper position on the last, locking the sideframe
in its proper position, the last, upper and sideframe constituting
a movable unit, thereafter moving the unit in relation to a sole
plate to form a sole molding cavity, placing an elastomeric
material in the cavity and molding a sole to the upper.
2. The method of manufacture of footwear as set forth in claim 1
wherein a plurality of lasts and side frames are mounted upon a
conveyor and moved relative to the sole plates.
3. The method of manufacture of footwear as set forth in claim 2
wherein said lasts and side frames are of different configurations
to manufacture in sequence footwear of different sizes.
4. Apparatus for manufacture of footwear comprising a last, an
adjustable side frame, means for locking said side frame directly
to said last in its adjusted position, said last, side frame and
locking means forming a unitary structure, a separate sole plate
forming with said unitary structure a mold cavity, and means for
exerting relative movement between said sole plate and said unitary
structure to mold a sole to an upper.
5. Apparatus for manufacture of footwear comprising a plurality of
lasts, an adjustable side frame for each last, means for locking
each said side frame directly to its respective last in its
adjusted position, said last, side frame and locking means forming
a unitary structure, a plurality of said unitary structures being
mounted on a conveyor, said unitary structures being of different
configurations, sole plate means forming with each unitary
structure a mold cavity, and means for exerting relative movement
between said sole plate means and each said unitary structure to
mold a sole to an upper.
Description
BACKGROUND OF THE INVENTION
It is customary to last shoe uppers of material such as leather on
wooden lasts to obtain the stretching of the leather for the
desired permanent fit. The so prepared upper often must be
transferred to a metal last for sole-attaching (securing a sole to
the shoe upper), be it by cementing, vulcanizing, or molding sole
material. Frequently sole-attaching machines are used having a
turret with several arms, each carrying a last, with a single sole
pressure plate fitting all lasts on the turret located beneath the
turret. The operator has access to one last for mounting an upper
while another last with its upper is in contact with the sole
pressure plate, which frequently is combined with a side frame
determining the side contour of the sole.
SUMMARY
The placing and lasting of the shoe upper on the last of the
sole-attaching device requires skilled operators as great care is
needed to assure that the back seam and the instep of the shoe is
in the right location and is straight.
According to the invention, satisfactory lasting is facilitated by
providing means for the operator to control the correct position of
the upper on the last, before moving the lasted upper to the
sole-attaching position.
The side-frame, hitherto located in relation to the sole pressure
plate, is located now directly against the last and secured to the
last before moving the upper into the sole-attaching position. This
allows the operator to see the shoe bottom pressed against the side
frame and to discover any irregularity which might exist. A
correction is then possible before a sole is attached. This is of
great advantage not only for weltless uppers, but also for
prewelted uppers where the closing of the usually divided side
frame can be used to push the welt inwardly and thereby tension
additionally the upper on the last.
As shoes are sold and shipped from the factory in assortments
(cases) composed of many sizes and each size often in several
widths, with several pairs of shoes in the most commonly sold sizes
and only one pair in rarely sold sizes and widths, then the
necessity of having three identical lasts for each mold increases
the already high mold costs as well as the costs of the many mold
changes needed to cover the entire range of sizes and widths.
For sole-attaching by cementing or by molding of elastomeric
material directly to the shoe bottom, sufficient time has to be
allowed for the vulcanization of the rubber sole or for the cooling
of the thermoplastic, molten elastomer.
To satisfy this need, sole-attaching machines are widely used which
have a three or four arm turret above a single sole pressure plate
or sole piston, so that the operator can use the vulcanization or
cooling time to remove from a second last on a second arm a
finished shoe and to place and last an upper on the second or a
third last on a third arm. All lasts mounted at a given time on
such turret are identical to fit the single sole pressure plate or
sole mold. This has the drawback not only of doubling or tripling
the last costs, but also that every time the size or width of the
shoe is to be changed, two or three lasts have to be changed for
every change of the sole cavity determined by the side frame and
the sole plate.
One object of the invention is to reduce the mold costs by using
only a single last for each mold without reducing the output per
machine. Another object of the invention is to reduce the number of
mold changes per machine.
Other features and advantages of the invention will be apparent
with reference to the following specification and drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic view showing a turret machine with four
arms;
FIG. 2 shows in larger scale a view of the device according to the
invention of a last with attached side frame and means to position
and lock the side frame in relation to the upper on the last;
FIG. 3 shows a first piston;
FIG. 4 shows a second piston for use with the device of FIG. 2;
FIG. 5 shows a unit mold comprising the unit of FIG. 2 with
attached sole piston; and
FIG. 6 shows a cross section of the unit of FIG. 2 with the side
frame secured to the last.
DESCRIPTION OF THE PREFERRED EMBODIMENT
According to the invention, each arm 2 of the turret 1 carries a
last 3 differing in dimensions, such as right or left, width or
size, from the last carried by the next turret arm. The operator
places an upper 5 on the last carried by the turret arm in mounting
position 6. When the turret 1 is indexed (manually or by power
means), the upper 5 moves into the molding position 7 where the
molding compound is injected into the cavity formed by the mold 8,
the usually split side frame 9 and the piston 10 with the
configuration of the sole bottom. The piston or sole pressure plate
10 rests on the molding table 11, which might be chilled to reduce
the time needed for the sole compound to solidify.
The invention provides further that the side frame 9 fitting the
specific last is placed into the desired final position in relation
to the last and the upper placed thereon while the turret arm is
still in the mounting position. This allows not only easy visual
inspection of the seating of the upper on the last but also
lengthens the cooling time in the molding position. The last
carries correspondingly the side frame 9 as well as last support
extensions 13 to locate the side frame 9 as well as locking means
14 to maintain the relative position of last 3 and side frame 9
while moving from the mounting position into the molding position.
There the side frame 9 surrounds the piston 10 resting on the
molding table 11, placed there manually or by power means. It is
understood that always the piston fitting the side frame and last
coming into the molding position has to be brought into the correct
position on the molding table. The ease with which this can be done
allows, in further improvement of the method of the invention, to
provide a first piston 15, as shown in FIG. 3, to mold a relatively
flat, heel-less first sole layer to the upper, and to mold without
further indexing of the turret, a heel or outer sole and heel to
said first sole layer. If desired, the turret can be indexed as
usual until the upper with the first sole layer reaches the
mounting position again. Then inserts for the heel or sole, or
both, can easily and accurately be placed onto the first sole layer
before indexing again into the molding position. The division of
the sole into a first and a second layer, be they the same or
different thermoplastic material, will always bring a reduction in
required cooling time because of the poor heat conductivity of such
material.
The aforementioned improvement of placing not only the last but
also the side frame on the turret arm, and have it travel together,
is further broadened by connection also the mold component forming
the sole bottom to the last traveling with the turret arm. Then the
entire closing of the mold occurs before the indexing into the
molding position. As the last and the side frame as well as the
locating means 13, 18 and the locking means 19 are interconnected,
the entire unit can be adjusted off the machine and instantly
exchanged. In such case, as shown in FIG. 5, the sole bottom plate
16 can be exchangeably fastened to the turret arm 17 or the entire
unit mold can be exchangeably mounted with the last locked to the
turret arm 17. A machine with 2 turrets with four arms each
equipped according to the invention takes care of four complete
sizes, right and left, compared to production of a single size with
the customary equipment.
These advantages are important not only for injection molding of
soles, but also for molding of heat setting elastomers, such as
rubber ornaments.
As shown in FIG. 5, the locking means 13, 18 are posts extending
both from the last carrier and from the frame with locking means
where these posts meet. This allows to set the contact between
upper and frame lip independently from the action of the closing
device 19 or other pressures.
FIG. 6 shows how the posts 13 hold the lip 24 of the side frame in
the desired, spaced relation to the last 5 to push the welt 26
inwardly and tighten thereby further the upper 5 to which the welt
is secured by the stitching 27. The side frame 9 has not only the
cavity wall 21 mating the contour of the sole piston (not shown in
FIG. 6) but also guide surfaces 22 to bring the piston into the
exact alignment with the side frame.
The threaded posts 13 allow the exact adjustment of the side frame
in relation to the last to suit different thicknesses of the
material of the upper before placing the unit of last and frame
onto the arm of the turret 1, thereby saving costly machine time.
The locking means 23, which might use cam surfaces as shown, assure
the rigid maintenance of the frame position also during the travel
from the lasting position to the sole-attaching or molding
position. The sole pistons, unencumbered by other cavity or
locating parts, are easily moved by hand or mechanical means to
have always the piston fitting under the frame (and last) when the
unit arrives in the molding position.
The absence of any mechanical connection between the unit of last
and frame on the one hand and the piston on the other hand allows
in further improvement of the method according to the invention to
mold closed cell elastomeric soles to the upper by providing a
sequence of decreasing, increasing, and again decreasing the cavity
volume by the relative movement between last and piston.
* * * * *