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Патент USA US3056992

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Oct. 9, 1962
s. SNITZER
3,056,984
METHOD OF CEMENTING SOLES TO SHOES
Filed Jan. 6, 1.961
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INVENTOR.
BY
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ATTORNEYS
3,055,984
Patented Oct. 9, 1962
2
3,056,984
METHOD OF CEMENTING SOLES T0 SHOES
Saul Snitzer, Worcester, Mass.
(% B-W Footwear Co. Inc., Webster, Mass.)
Filed Jan. 6, 1961, Ser. No. 81,015
5 Claims. (Cl. 12-142)
This invention relates to the art of shoemaking and
more particularly comprises a new and improved method
of cementing soles to uppers.
‘In shoe factories today it is common practice in the as
sembling operations to transport shoes from operator to
operator on racks holding one or more case lots.
Each
operator completes his operation on all of the shoes in a
rack before wheeling the rack to the operator who per
forms the next step in assembling the shoes. This prac
tice is commonly followed in both the lasting and bot
toming operations. In this common practice, intentional
delays are incorporated into the assembling sequence to
allow certain things to occur. For example, after the op
erator applying cement for sole attaching completes this
the upper is passed through a heating chamber wherein
the temperature is maintained at approximately 160° F.
The upper remains in that chamber for approximately
one minute. While in this heater the evaporation of the
solvents is accelerated as the solvents are drawn from the
interior of the cement coating. I theorize that more im
portant than the actual temperature reached by the cement
is the change in temperature experienced by the cement
from the air cooling and drying step to the heating step.
Upon leaving the heater, the upper is directed through a
force cooling chamber. The air in the cooling chamber
is circulated by fans or blowers which serve to carry away
the vapor barrier formed about the upper by the evap
orated solvents, which would inhibit further evaporation.
The forced cooling of the cement coating is continued for
a period of approximately one minute at a temperature of
about 60° F. Thereafter, the uppers are passed through
a reheating chamber which serves to reactivate the cement.
The reheating chamber has a temperature of approxi
mately 85° F. and the shoes remain in that chamber for
approximately forty seconds. During that time the ce
ment becomes tacky and acquires maximum bond
step on all of the shoes in a rack, the rack is set aside for
strength.
several hours to allow the cement to set and dry. While
The preheating of the cement before its application to
the time required for the cement to set and dry varies
with different upper stock, even with shoe uppers of a 25 the upper has several advantages. Not only does the pre
stock most conducive to setting and drying of the cement,
approximately two hours are required for this result to
heating accelerate the evaporation of the solvents but in
addition more uniform flow of the cement is obtained
from the cement applicator, and stripping and puddling
be effected unless setting and drying is arti?cially ac
are avoided. The viscosity of cold cement is lower than
celerated.
Recently, efforts have been made to employ “rink” sys 30 that of heated cement and, therefore, cold cement is more
di?icult to control. When the viscosity of the cement
tems in the manufacture of shoes, particularly for the
is somewhat elevated, more uniform application is pos
bottoming operations, wherein the shoes are processed on
sible.
an individual basis and are passed from one operator to
These and other objects and features of my invention
the next immediately upon the completion of a particu
lar step in the manufacturing process. By employing the 35 will be better understood and appreciated from the fol
lowing detailed description read in connection with the
rink system, manufacturers hope to reduce the number of
accompanying drawing, wherein:
shoes in process and thereby reduce the number of lasts
FIGURE 1 is a box diagram representing the sequence
required for a given factory output. It will be recognized
of steps in the shoemaking process of my invention; and
that lasts constitute one of the major capital investments
40
FIGURE 2 is a diagrammatic view of a conveyor as
in the operation of a shoe factory.
sembly about which the various shoemaking steps of my
The successful operation of a rink system depends at
invention may be practiced.
least in part on the elimination of long periods during
In FIGURE 1 the sequence of steps followed in attach
which time no function is performed on the shoes. Thus,
ing the sole to the upper are represented separately in
for a rink system to operate successfully it is obviously
necessary to eliminate the ordinarily long period required 45 box form. It will be appreciated that the steps of my in
vention take place after the normal lasting operations are
to condition the cement. Some means must be employed
completed and are in no Way dependent upon the particu
to accelerate the natural setting and drying process.
lar method of lasting employed. The ?rst operator em
The primary object of my invention is to provide a proc
ployed in the practice of my invention takes a prelasted
ess wherein the setting and drying of the cement is
markedly accelerated. Several direct advantages ?ow 50 upper and applies a heated coating of cement to its over
lasted margin, as suggested in box 10. Thereafter, the
from the acceleration of cement setting and drying. First,
several steps as represented by boxes 12, 14, 16 and 18
if the setting and drying occurs in a very short period of
are conducted automatically without the attention of an
time, a rink system may be employed most successfully
operator to condition the cement coating. The ?rst of
in the bottoming operations.
A normal outgrowth of the rink system is the use of 55 these automatic steps is the air drying of the cement for
approximately two minutes. During this period the ce
conveyors for transporting the shoes from operator to op
ment is permitted to respond to room temperature and
erator. The conveyor may also be used to carry shoes
cool. After a short period of air drying, the uppers and
through certain locations where conditions are established
more particularly their cement coating are exposed to a
that accelerate the conditioning of the cement. It is obvi
ous that the more rapid the conditioning of the cement, 60 high heat zone of approximately 160° F. for about one
the shorter and less expensive the conveyor required.
To accomplish the primary and other objects of my in
vention, I subject the cement applied to the upper to a
series of different conditions in rapid sequence. Prefer
ably, the cement is preheated and applied to the shoe 65
at a temperature of approximately 110° F.
After the
minute during which time the cement coatings experience
a marked change in temperature.
Thereafter, a forced
draft is directed across the uppers to remove the vapor
barrier surrounding the shoes. The shoes may be ex
posed to the forced draft for a period of approximately
one minute. The last automatic step performed in the
process is the reheating of the cement coating to reactivate
it. The reheating is done at a temperature slightly in
excess of normal room temperature, i.e., approximately
proximately two minutes during which time the solvents
at the surface of the coating evaporate. This slow cool 70 85° F., and occurs for a period of approximately forty
seconds. After the cement is activated by the reheating,
ing avoids the formation of a ?lm on the surface which
the sole is applied as indicated by box 20, by a second
would retard the dispersion of the solvents. Thereafter,
cement coating is applied to the overlasted margin of the
upper, it is permitted to cool at room temperature for ap
3,056,984
3
4
operator in the system. The sole may or may not be pre
coated with cement, and if precoated may be reactivated
The conditioning of the cement is continued by pass
ing the lasted uppers bearing the cement coating through
a zone of rapidly moving cool air lying intermediate the
by a separate heater or otherwise brought to a tacky
state. The particular system followed in the treatment
of the sole will be determined by the sole material and
the nature of the upper stock. Regardless of the condi
tion chosen for the sole, it is placed on the bottom of the
lasted upper and the parts are subjected to pressure to
ends of the tunnel 40‘ and created by the fans 46.
The
fans 46 serve not only to cool the area but in addition
serve to carry away the vapor barrier which forms about
each of the uppers as the solvents evaporate. In effect,
the fans create a porous or absorbent atmosphere about
the cement coatings to accelerate the setting and drying
Having described brie?y the several steps of my inven 10 of the cement. In the testing of my invention, a sixty
second interval was adequate substantially to complete
tion, I will now describe each of the steps in greater detail
the setting and drying of the cement.
referring to the diagrammatic view of a conveyor and
To complete the conditioning of the cement for sole lay
ancillary equipment shown in FIGURE 2. At the same
effect a maximum bond in the ordinary manner.
ing, it is only necessary to subject the cement once again
time, speci?c times and temperatures will be identi?ed as
employed in an actual model of my invention. In FIG 15 to heat. This is accomplished by heaters 48 lying at the
end of the tunnel 40, which create a warm atmosphere for
URE 2 a tube 22 is shown surrounded by a heating coil
the uppers. This atmosphere at a temperature of ap
24, which carries cement to nozzle 26. The cement may
proximately 85° F. in forty seconds reactivated the ce
be any heat conditionable adhesive, such as a thermo
ment during testing so that it was in the proper condition
plastic or thermosetting cement. Such thermoplastic ad
hesives as Hycar cement and neoprene are typical ex 20 for sole laying. When the shoe uppers leave the tunnel
44) at the exit 50, an operator stationed adjacent pulley
amples of the cements employed. A distinct advantage
38 removes the uppers from the conveyor, applies the
is derived from heating the cement in the tube 22 as op
sole and places them in a press (not shown) and actuates
posed to heating it in an open container (not shown) or
the press to assist in the formation of the bond between
at the nozzle 26. When the cement is heated in an open
the sole and upper stock.
container many of the solvents contained in the cement
From the foregoing description it will be appreciated
are driven off and, therefore, the chemical formulation
that by the practice of my method approximately four and
of the cement is changed and the cement is no longer in
one-half minutes after the cement is applied to the over
the condition intended by the manufacturer at the time
lasted margin the sole may be attached to the upper. The
of application. The limited physical size of the nozzle
26 does not allow adequate heat to be introduced into 30 sequence of steps recited uniformly produce a quality
product with many bene?ts to the manufacturer. The
the cement to elevate its temperature to the degree de~
elimination of the use of racks in good part does away
sired. Experiments have indicated that the best results
are obtained when the cement is applied at a temperature
of approximately 110° F. The coil 24 may cover a length
of approximately two feet on the feed tube 22 and this
with the need of cleaning of the shoes, as the shoes no
longer remain on the racks to accumulate dirt, dust etc.
The number of lasts required in’ the manufacture of shoes
distance is adequate to facilitate the introduction of the
is minimized and better production control is provided.
In the very limited time required for sole laying, proper
cement conditioning is effected and thus a better bond is
achieved between the sole and the upper. While quartz
heaters perform very satisfactorily for the application of
high heat at the inlet end of the tunnel 40 and infrared
lamps are most satisfactory in supplying the reactivating
heat necessary to elevate the cement to that temperature.
I suggest at 28 a lasted shoe upper upon which the
‘heated cement is being applied to the overlasted margin.
After the cement is so applied, the operator places the
last bearing the shoe on a pin 30 carried by the conveyor
32 travelling in the direction indicated by the arrows 34.
The two pulleys 36 and 38 describe the course followed
by the conveyor 32 and it is to be understood that one or
both of the two pulleys 36 and 38 may provide the drive
for the system. The lasted upper coated with cement
.on the overlasted margin is suggested at 28' in the posi
tion in which it is installed on the conveyor by the ce
menter. The conveyor carries the lasted upper exposed
to room conditions in the direction of tunnel 40 surround
ing a major portion of the upper run of the conveyor. In
the test model 102 seconds are required for the upper to
travel from the location shown at 28' to the mouth 42
of tunnel 40. During that time, the cement is air dried
and the solvents particularly lying at the surface of the
cement coating are allowed to evaporate. As the uppers
are unencumbered by shrouds, hoods or tunnels etc., the
solvents which dissipate from the cement move away from
the shoes and do not form a saturated atmosphere to
inhibit further evaporation of the solvents. After air dry
ing, the uppers coated with cement enter the tunnel 4t}
heat for the cement, any type of heat source may be used
and thus equipment costs are not prohibitive.
While I have described in detail a preferred embodi
ment of my invention, I do not intend to limit the scope
of my invention to the single embodiment illustrated and
described as various modi?cations may be made of it
without departing from the spirit of my invention. It is
intended that the breadth of this invention be determined
by the appended claims and their equivalents.
What I claim is:
1. A method of sole laying comprising the steps of pro
viding a lasted upper and a sole, applying a heated coating
of cement to the overlasted margin of the upper, air dry
ing the cement on the margin for approximately two
minutes, subjecting the cement coating to a heat of ap
proximately 160° F. for approximately one minute, there
after force cooling the coating of cement by directing
cooled air over its surface for approximately one minute,
next subjecting the cement coating to a heat of approxi
and are subjected to the heater 44 which creates a tem
mately 85° F. for approximately forty seconds, and there
perature of approximately 160° F. in its zone of the tun
after pressing the sole on the overlasted margin to bond
the sole and upper together.
2. A method of sole laying comprising the steps of
nel.
The elevated temperature at that location causes a
rapid change in the temperature of the cement coating
and the solvents lying deeper in the coating below the
surface are caused to evaporate. However, if the uppers
had not been given an opportunity to cool at room tem
providing a lasted upper and a sole, applying cement to
the overlasted margin, heating the coating by subjecting
it to a temperature of 160° F. for approximately one min
ute, then directing a forced draft of cool air at a tempera
perature preceding entry into the tunnel 40, a ?lm may
have formed over the surface of the cement which would 70 ture of approximately 60° F. for approximately one min
ute over the cement, and thereafter reactivating the ce
impair further evaporation of the solvents and make it
ment and pressing the sole on the overlasted margin to
particularly difficult to drive the solvents from the ce
bond the sole and upper together.
ment. To draw the solvents through the ?lm would re
3. A method of securing a sole to an upper comprising
quire more than the 78 seconds of high heat found ade
quate in the practice of my process.
75 the steps of providing an upper and a sole, applying a heat
3,056,984
activatable cement to the bottom of the upper, heating the
upper for approximately one minute at a temperature of
160° F., breaking the vapor barrier on the surface of the
coating by rapidly cooling the cement with moving air,
and thereafter reactivating the cement coating by the ap
plication of heat and pressing the sole and upper together.
4. A method of securing a sole and an upper together
comprising the steps of coating the bottom of an upper
with a heat activatable adhesive carrying a heat reser
voir, permitting the coating to cool at room temperature 10
for approximately two minutes after the coating is applied,
directing heat to the surface of the coating immediately
after cooling to accelerate the evaporation of solvents
in the cement, thereafter rapidly decreasing the tempera
ture of the coating while evacuating the solvents in the 15
atmosphere adjacent the surface of the coating to further
accelerate the drying of the cement, and thereafter reheat
6
ing the coating and pressing the sole thereon to bond the
sole and upper together.
5. A method of securing a sole to an upper comprising
the steps of providing a lasted upper and detached sole,
applying a coating of heated cement to the overlasted
margin of the upper, dissipating the surface solvents in the
cement, and thereafter rapidly increasing the temperature
of the coating to evaporate the solvents in the interior of
the cement, directing rapidly moving cooling air over the
surface of the coating to remove the vapor barrier about
the cement created by the evaporating solvents, and there
after reactivating the cement coating and pressing the sole
thereon to bond the sole and upper together.
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,940,096
Brom?eld ____________ .._ June 14, 1960
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