Note: Descriptions are shown in the official language in which they were submitted.
~37'~1'7
,
BACKGROUND OF THE INVENTION
The present invention is directed toward apparatus for
edging reinforced elastomeric stockl hereinafter referxed to as
a gum edger, and a method for the edging of such stock. With
the exception of modern, cast elastomer technology, which does
not require reinforcement, it has been well recognized that
conventionally employed elastomeric stocks, e.g a I rubber, do not
possess the inherent strength either to maintain their integrity
during the processing steps necessary to obtain the desired
article or ultimately to function as an acceptable product when
subjected to normal use. Thus, the elastomers have been rein-
forced in sheet form, generally referred to as reinforced elas-
tomeric fabric, by the inclusion of embedded fibers, mono or
polyfilament, which are considerably less extensible than the
elastomer. These filaments, or reinforcing cords~ include
materials such as cotton, synthetics such as rayon, nylon,
aramid, polyamides and polyesters, fiberglass and metallic wire,
particularly steell either single strand or cabled.
Calendering has been the historic way in which to make
;20 reinforced elastomeric abric, especially for tire plies. When
the elastomer is calendered the reinforcing cords are oriented
parallel to the length of the sheet emanating from the calender.
As such, in order for the reinforcing cords to be angularly or
perpendicularly inclined with respect to a circumferential
reference plane when the reinforced elastomeric fabric is incor-
. ~ported in a tire, it is necessary to cut it either on the bias,
or perpendicular to he longitudinal strands of reinforcement.
: '
:~ 30
3'~ 7!`7
A more recently developed apparatus for making rein-
~orced elastomeric ~abric involves the manufacture of a re~a-
tively narrow reinforced ribbon which is cut into strips o~
predetermined length which strips are subsequently joined and
may be stitched together to form the abric in desired widths
wherein the strands of reinforcement are oriented angularly
or perpendicularly to the len~th of the fabric. Suitable
apparatus for making fabric in this manner is described in U.S.
Patents NoO 3,803,9~5 and 4,087,3081 owned by our common
assignee, The Steelastic Company.
Irrespective of the apparatus and method employed,
l.e., calenderiny or assembly of strips of reinforced ribbon,
when the reinforcing filaments are metallic, it has been recog-
nized that the exposed ends o reinforcement along the cut edges
of the reinforced elastomeric fabric cause an adverse effect
upon the products, most particularly radial or bias tires,
within which they are incorporated. Metallic reinforcing gen-
erally eYnployed is steel wire either monofilament or cabled and
tire manufacturers have long striven to obtain good adhesion
between the elastomer and embedded metallic reinforcement by
incorporating certain rubber soluble cobalt containing salts
within the elastomer. Although the wire is plated or coated
with brass to resist rusting or an adhesive for enhancement o~
adhesion, where the wire has been severed, an exposed surface is
presented which immediately begins to oxidize upon contact with
the atmosphere. While adhesion between chemically clean steel
and some elastomers may be acceptable, such oxidation is -to be
avoided inasmuch as the elastomeric material in which the wire
is embedded does not adhere to the wire as it becomes oxidized.
In the manu~ac-ture o~ steel belted bias and radial
tires, one or more circumferentially oriented belts are located
beneath the tread stock to maintain the integrity and shape o~
-2-
~L~q33~t7t`~
the tire during inflation and subsequent load. The steel rein-
forcement in th~se belts is commonly disposed at an angle from
the length of the belt~ and subsequently with respect to a plane
perpendicular to the rotational axis of the tire, and thus, when
th~ belt is constructed, all of the severed ~nds of steel rein-
forcement axe exposed along both sides of the belt. In addition
to making such belts difficult to handle by the worker, oxida-
tion of these ~xposed ends before the belt can be incorporated
in a tire, gives rise to subsequent belt edge separation in the
tire~
Belt edge separation is a condition which presently
accounts for not only a majority of failure of radial passenger,
truck and off the-road tires but alsor for the decrease in tires
acceptable for retreading. During use of the tire for distances
often exceeding 50,000 to 100,000 miles (80,500 to 161,000 km),
these once exposed ends of reinforcement, now surrounded by
; underlying carcass plies and overlying ~read, fail to adhere to
the elastomer. With constant flexing and extension of the
elastomexic material as well as the steel reinforcement, atten-
dant use of the tire, the edges of the belt eventually break
loose from the carcass plies in the reyion of the shoulder of
the tire. Although the condition once started is not curable,
if it is not dete~ted or if it be ignored and the tire is not
replaced, failure of the tire results by either partial or total
separation of the tread from the body of the tire during high
speed continued operation.
The latter result is highly intolerable on the highway
and has been experienced in this country an appreciable extent
on passenger car tires, as well as in other countries where
upper speed limits are not posted it is not uncommon for speeds
of lO0 mph (161 kmph) to be driven for several hours, precipi
tating such failure with a high probability of disastexous
-3
resultsO While such use of tires may not be expected in this
country, that fact alone does not obviate the need to eliminate
belt edge separation in steel belted radial tires.
Oxidation of the exposed ends of the steel wire
reinforcing may be minimized by incorporating the ~abric into
the tire soon after it has been made or, by carefully control~
ling the environment surrounding the fabric prior to its in-
tended use. However, such eEforts are rarely practical and the
fabric is often stored for a time o~ from several days to per-
haps several months in a warehouse prior to its use and it isduring this period that oxidation of the exposed wire reinforce-
ment occurs.
One method developed and employed to eliminate oxi-
dation o the exposed wires is to calender a sheet of a suitable
elastomer from which strips may be cut, to be appIied to the
exposed edges of the rein~orced elastomeric fabric, e.g.,
carcass ply or tread belts. Such strips, referred to as cushion
gum/ have been relatively wide, e.g., 3.75-5.0 cm wide and
approximately 0.038 cm thick, are applied to one side of the
edge of the fabric, subsequently folded over onto the other side
and are then stitched thereto. However, when the cushion gum is
olded over the edge of the fabric, alignment as well as handl-
ing is difficult due to the inherent tack of both surfaces,
fabric and gum, and inevitably results in an air pocket at the
edge where, first, the desired adhesion be~ween steel and elas-
tomer is not obtained and, secondly, wherein oxidation is
neither abated nor precluded.
Adhesion-enhancing additive mater'als are most feas-
ibly employed in cushion gum which is to be applied immediately
after the wire shearing operation which provides a chemically
clean steel surface for a short period of time. Al~hough this
~9/3~ 7
cushion gum is, however, often applied to the belts at he time
of tire construction, after the fabric may have been stored for
a time sufficient for oxidation of the exposed wire ends to have
occurred, failure of the belts in tires so constructed has been
found, ne~ertheless, to be significantly reduced. However, the
treatment is not without its faults, which are increased costs
in both labor and materials î increased thickness of the ply at
the edges; and, the presence of air pockets in the area of the
gummed edges which permit oxidation. Moreover, work with the
application of various elastomers has demonstrated that the more
suitable compounds cannot be calendered into thin strips for
subsequent gum edging. Despite many attempts by the industry,
gum edging remains a costly, time-consuming process and the
disparity between these facts and the benefits gained by the
employment of the process remalns great enough to limit gum
edging to only steel reinforced elastomeric belts for radial
: truck tires. Considering tha benefits in terms of longer tire
life and safety, it becomes highly desirable to employ the
process of gum edging or all tire manufacture, commer.ical,
~, truck tire and of-the-road, and passenger.
Another problem inherent in tires is their adverse
efect to internal discontinuities, such as regions where hinge
points exist. Hinge points frequently coincide with abrupt ..
endings of the fabric, e g., endings of the ply turn-ups, end-
ings of break and shock plies, and of belt edges. The recent
trend toward reducing tire p~ies, iOe., 2-ply and l-ply (radial)
passenger car tires in l~ieu o 4-ply, and 4-ply, 6 ply and l-ply
~radial) in lieu o~ 12~ply for many of the truck tire sizes, has
been greatly ~acilitated by the use o cord reinforcement of
greater diameter, _ ~, 1260/3 rather than 840/2, with a con-
sequent increase in the gauge o the e~astomeric fabric which,
in turn, has contributed significantly to the development of
hinge points.
The problem is particularly apparent in the construc-
tion of a typical truck tire wherein several plies are cut to a
common width and then offset to provide a step-off. When the
plies are turned up about the bead regionl one side has an
exposed step-off and the other side has a buried step-off. Ply
endings in the turn-up region not only lead to the possibility
of air entrapment, but also, ply distortion in the case of
buried turn-ups and an abrupt change in ben~ing stiffness. The
overlying ply must make a sharp bend over the buried and exposed
step-offs creating a hinge point and tending to trap air. While
gum strips may be applied to cover the terminal regions of the
plies, and to provide elastomer to flow, the disadvantages are
increased~cost, a tendency to entrap air and the creation of
~: ancther edge.
Another ply construction very sensitive to the abrupt
: ending of the fabric is the buried shock ply -- a partial width
ply placed within the body of the tire, extending from mid-
sidewall to mid-sidewall and lying between the second and third
plies. The ends of such plies create a possibility for distor-
tion, air entrapment and hinge points~ The application of a gum
strip may provide sufficient elastomer to flow for the elimi-
nation of some distortion but, in and of itself, provides an-
other discontinuity.
Again~, gum edging could be the solution to the elimi~
nation of abrupt termination o~ the plies with a suitable ap-
paratus and method for the application of an elastomer in a con-
fi~uxation and quantity which would a~ilitate a transition
substantially ~ree from distortion between ply endings and
overlying plies. ~ ~ :
~n~37~'7~
SUMM~RY OF T~E INVENTION
It is, therefore, an object of the present inven-tion
to provide an apparatus and method for edging reinforced elas~
tomeric fabric.
It is a further object of the present inventîon to
edge the fabric in a manner which eliminates oxidation of ex-
posed steel reinforcement.
It is another object of the present invention to edge
the Eabric in a manner which eliminates entrapment of air be
tween the elastomer and the edge to which it is applied and
facilitates maximum adhesion between contiguous elastomeric
surfaces and with any suitable reinforcement filaments.
It is yet another object of the present invention to
edge the fabric in a manner which substantially ~liminates
abrupt termination of plies which are subsequently employed in
the manufacture of reinforced elastomeric articles, particularly
tires.
It is a further object oE the present invention to
provide an apparatus and method for edging reinforcing bel-ts for
bias and radial tires in a manner which substantially eliminates
belt edge separation in the tire during its life.
It is:stiLl a further object of the present invention
to provide an apparatus and method for edging rei.nfGrced elas-
tomeric fabric which will facilitate the manufacture of new
tires and the retreading of used tires of improved qualityO
It is still another object of the present invention to
edge the fabric with more suitable elastomeric compositions than
have been employed via conventional gum edging techniques; to
edge. in a less costly manner; and to control the quantity and
profile of the sdgs bsing applled.
These and other ob~ects, together with the advantages
thereof over existing and prior art forms, which shall become
--7--
3~7'~
, .
apparent from the specification which follows are accomplished
by means hereinafter described and claimed.
In yeneral, apparatus embodying the concept of the
present invention includes a frame, a table for support of ~he
reinforced elastomeric fabric, at least one extruder assembly
adjacent the table for the application of a suitable elastomeric
material directly onto an edge of the elastomeric fabric and
means for moving the elastomeric fabric over the table. An
alternate embodiment includes a frame, means for support of the
elastomeric fabric and at least one extruder assembly adjacent
the means for support for the application of a suitable elasto-
meric material directly onto an edge of the elastomeric fabric.
The preferred method for applying elastomeric material to an
edge of reinforced elastomeric fabric includes the steps of
passing the elastomeric fabric over the means for support, ex-
truding the elastomeric material through a head and imparting a
first edge therein compatible with an edge of the elastomeric
~:
fabric, and joinin~ the extruded material to an edge of the
elastomeric fabric by forcing the material into substantially
all of the exposed surfaces thereof. The invention further pro-
vides for a second extruder assembly which, in conjunction with
the first/ applies the elastomeric material to opposed edges of
the elastomeriç fabric passing therebetween.
DE5CRIPTION OF THE DRAWINGS
Fig. 1 is a perspective view of an apparatus for
edging sheets o~ rein~orced elastomeric fabric embo~ying the
concept of the present inve~ntion and ope~ative according to the
method thexeof; a portLon of the apparatus responsible for
moving the fabric therethrough having been removed for clarity;
Fig~ 2 is a side elevation of a portion of the appara-
tus, partially in section, depicting the hraking mechanism for
one of two movable extruder assemblies;
--8--
7~
Fig~ 3 is a partial horizontal cross section taken
substantially along line 3-3 of Fig. 4;
Fig. 4 is a partial vertical cross section taken sub-
stantially along line 4-4 of Fig. 2;
Fig. 5 is a top plan, partially in section, of one of
the extruder heads~
Fig. 6 is a frontal elevation of the extruder head and
a cross section of reinforced elastomeric fabric in position for
receiving a gum edge;
Fig. 7 is a view similar to Fig. 6 depicting the de-
posit and preliminary shaping of a gum edge along one edge of
elastomeric abric;
Fig. 8 is a side elevation of the complete apparatus,
depicting the drawing ~echanism;
Fig. 9 is a top plan of the apparatus wherein the
support table, extruder assemblies and a portion of the carriage
assembIies ha~e been removed to present details of the braking
mechanisms and the carriage shafts;
Fig. 10 is a schematic perspective of the braking
mechanism; and,
Fig. 11 is a perspective view of an alternate embodi-
ment for edging sheets of reinforced elastomeric fabric embody-
ing the concept of the present in~ention and opera~ive according
to the method thereof.
DESCRIPTION OF _HE~P~EFERRED ~MBODIMENT
The impro~ed apparatus for applying a gum edge to
sheets of reinforced elastomeric fabric and embodying the con-
cept o the present invention, is generally designated by the
numeral 10 on the attached drawings. The apparatus 10 has a
rigid base rame ~l from which is supported the primary mecha-
nisms, i~e., a support tabLe 1?, inboard and outboard carriage
assemblies, 13 and 14 respectively, inboard and outboard braking
~3'~
mechanisms, 15 and 16 respectively, inboard and outboard ex-
truder assemblies, 18 and 19 respectively, and a drawing mecha~
nism 20.
The operation of the subject apparatus shall be dis-
cussed in detail following description of the components thexe-
of. Before proceeding, however, it may be helpful to state that
the apparatus 10 is capable of applying a gum edge to opposite
sides of a sheet of reinforced elastomeric fabric (Fig. 5) pass-
ing therethrough in the direction of the arrow A. ~he fabric
may have been calendered in a conventional manner or prepared on
an apparatus, such as is described in U.S. Patents No. 3,803,965
or 4,087,308, both of which are owned by our common assignee,
The Steelastic Company, and may, of course, be reinforced with
any of the conventionally employed filaments.
Returning now to the description, the support kable 12
includes a plurality of individual conveyor rollers 21 carried
in six banks 22-27, each of which includes angle brackets 28
for support of the rollers 21.
The roller banks 22-24 are mounted on carriage assem~
bly 13 which includes two parallel roller frames 29 and 30.
Sim.ilarly, the roller banks 25-27 are mounted on carriage assem-
bly 14 which includes parallel roller frames 31 and 32 (Fig. 8).
The roller frames 29 and 30 of carriage assembly 13 are sup-
ported at one end by a roller 33 mounted in a suitable bracket
34 affixed to horizontal frame members 36 and 38 forming the
upper surface of frame 11. At their opposite end, the roller
~rames 29 and 30 are bolted to a cross plate 39 which rests upon
and moves over bedplates 40 and 41 carried directly by frame
members 36 and 38. In similar fashlon, the roller frames 31 and
32 are supported at one end by a roller 42 (Fig. 8) mounted in a
bracket 43 affixed to horizontal frame members 38 and 44, re-
: specti~ely, of frame 11. At the opposite end, roller frames 31
~ O--
3 7 ~ ~
and 32 are bolted to a cross plate 45 resting upon and movable
over bedplates 46 and 48 carried by horizontal frame members 38
and 44.
The carriage assemblies 13 and 14 further include
shafts 50 and 51 provided with handwheels 52 and 53~ respec
tively. Shaft 50 passes th.rough an end plate 54 affixed to end
frame member 55 and l~gs 56 and 58 of frame 11, at one end, and
is journaled at its opposite end in a suitable bearing 59 (Fig~
9) carried by an end plate 60 affixed to end frame member 61.
Shaft 51, for carriage assembly 14 is similarly journaled in a
bearing 62 carried by an end plate 63 affixed to end frame
member 64 at one end, and passes through end plate 54 as does
the shaft 50.
At least a portion of shaft 50 is threaded and engages
a block 65 having a threaded aperture 66 and welded to the
underside of cross plate 39 (Fig. 2). Shaft 51 threadably
engages a bLock 68 welded to the underside of cross plate 45 and
thus, rotation of handwheels 52 and 53 reciprocates the cross
plates 39 and 45, respectively, of carriage assemblies 13 and 14
along the bedplates 40, 41, 46 and 48. As depicted in the
drawingsl the carriage assembly 13 and roller bank~ 22-24 can
move toward and away from carriage assembly 14 a short distance
o~ approximately 1-2 inches (2 5-5 0 cm) while rec.iprocal move-
ment of carriage 14 and roller banks 25-27 with respect to
carriage assembly 13 is grea~er, e g., approximately 30 inches
(75 c~. Thus,~the width of the table 12 can be varied to
accommoda~e many dif~erent slzed elastomeric fabrics from the
relati~ely narrow beLt plies to the wider body plie6. Carriage
assembly 14 can be~quickly positioned to an approximate width
and subsequent fine adjustments can be made by ~ovement of
carriage assembly 13.
~11-
,
~3~7~7'-7
The braking mechanisms 15 and 16 are functionally
identical and include twin shafts 75-76 and 78-79. The shafts
75 and 76 are associated with the carriage assembly 13 and pass
through end plate 54 on ei-ther side of carriage shaft 50.
~andles 80 and 81 are provided ~o turn the brake shafts for
locking and/or releasing the carriage cross plate 39. The brake
shafts extend parallel with carriage shaft 50, through end plate
60, and are held in suitable bearing assemblies 82 and 83.
Shafts 78 and 79, associated with carriage assembly 14, pass
thrGugh end plates 54 and 63 having handles 84 and 85 at plate
54 and are held at plate 63 in bearings 88 and 89.
With specific reference to Figs. 2~4 and 10, the
detail and operation of braking mechanism 15 can best be ex-
plained. The brake shafts 75 and 76 are each provided with a
cam 90 and 91, respectively, nonrotatably affixed thereto via
keys 92 and 93. The shaft 75 has an elongated keyway 94 having
~:: a length at least as great as the extent of travel permitted
carriage assembly 13. Twin guide plates 95 and 96 are afixed
to the underside o cross plate 39. Plate 95 has notches 98 and
:~ 2Q 99 as does plate 96 at 100 and 101 which receive the inner sides
of bedplates 40 and 41, functioning -to maintain cross plate 39
in alignment as it is reciprocated. The centxal portion of each
plate is bridged as at 102 and 103 to form a passageway for
carriage shaft 50.
Beneath the notch 98 -the guide plate 95 carries a yoke
104 throuyh which~the brake shaft 75 passes. A second yoke 105
: beneath the notch 99 receives the brake sha t 76. Yokes 106 and
108 are also provided in guide plate 96 to receive the sha~ts 75
and 76, respectively. As clearly depicted in Fig. 4 the cam 90
on brake shaft 75 cannot pass beyond either yoke 104 or 106.
When movement o the caxriage 13 is desired, the brake shaft
: handles 80 and 81 are positioned as in ~ig. 2 and it is seen
-12-
.
that cams 90 and 91 are spaced from overlying bedplates 40 and
41. By rotatin~ the handles 80 and 81, as depicted in Fig. 3,
the cams 90 and 91 are brought into engagement with the bed~
plates 40 and 41 thereby prohibiting further movement o-E the
carriage 13. So long as the cams do not engage the bedplates,
the cams are slid along their respective brake shafts by one of
the yokes provided in the twin guide plates.
Beneath carriage assembly 14, the shafts 78 and 79 of
braking mechanism 16 are also provided with cams 109 and 110,
respectively, which are positioned between twin guide plates 111
and 112 carried by cross plate 45. Details of the braking
mechanism 16 are structurally identical with those described in
conjunction with braking mechanism 15 and shall, therefore, not
be.repeated.
The extruder assembly 18 includes an extruder 120 and
extruder head 121 carried by an angle bracket 122 affixed to
cross plate 3~. The extruder 120 i5 driven by a motor 123
carried by another angle bracket ~not shown) affixed to the
underside of cross plate 39. A belt, behind guard 124 transmits
power from the motor 123 to a speed reduction unit 125 also
carried by angle bracket 122. The extruder 120 may be heated in
any conventional manner and has a feed port 126 through which
the elastomer, forming the gwn edge, is fed. A separate elec-
tric heat element 128 is connected at one side of the head 121
and a special orming wheel 129 is rotatably and movably affixed
at the opposite side thereof, the purpose of which shall be
described hereinbelow. ~ smooth plate 130 is provided in roller
bank 24 and may be raised or lowered in order to accommodate
dif~erent thicknesses o elastomeric fabric passing before the
extruder head 121 and forming wheel 129. The entire extruder
assembly is carried by and movable with carriage assembly 13.
-13-
.
7~
Similarly, the extruder assembly 19 includes an ex-
truder 131, feed port 132, extruder head 133, heat element 134,
forming wheel 135 and smooth plate 136. The extruder 131 and a
speed reduction unit 138 are carried by an angle bracket 139,
affixed to cross plate 45, and are driven via power belt 140
from a motor 141 carried by a bracket mounted on the underside
of cross plate 45. The entire assembly is movable with carriage
assembly 14.
A more detailed description of the extruder mechanism
19 may be made with reference to Figs. 5-7. The elastomer to be
extruded is fed via extruder screw 142 to the head 133 which
comprises upper and lower halves, 143 and 144, respectively,
which are connected via machine screws not shown. Preferably,
the bottom hal~ is connected to a mounting flange 145 which is
itself readily attached to the end of the extruder 131 with
~; screws not shown. The top half 143 is then connec~ed to the
bottom which facilitates cleaning of the head 133 when the
apparatus is not being used.
A conical flange 146 extends from the mounting flange
145 through which the extrudate passes into the head 133. Each
half of the extruder head has a tapered, generally semicylin-
drical throat 147 and 148 narrowing to an outlet 149 through
whioh the elastomer lS forced into a pre~etermined shape, e.g.l
circular, as depicted in Fig. 6. At the entrance of the throat,
each half is machined to fit over the conical flange 146. This
; design allows a locking seal to be formed between the halves
143 and 144, and of each with the mounting flange 145. During
operation of the~extruder 131, the extrudate is forced through
the flanges 145 and 146 and into the throat. ~ny tendency of
the halves 143 or 144 to draw away from the flange, when under
pressure r is checked by the locking engagement between the in-
clined suxfaGes of~the flange 146 and the mating, machined sur-
- -14~
: - :
~3~
faces of the head. Again, cleaning is not hampered, inasmuch
as the upper half is readily removable, vertically, from the
lower half.
A removable edge-forming plate 150 is fastened to the
hal~es 143 and 144 with screws and is provided with a protruding
edge 151 which forms a first edge in the elastomeric material
which is compatible with the edge of the elastomeric fabric to
be covered. The edge 151 which may have any desirable shape,
comprises, as shown, a small diameter metal rod 152, one side of
which serves to close the outlet of the extruder head down to
th~ narrow outlet por~ 149. By employing a cylindrical rod 152,
in the manner described, a thin ribbon of generally C-shaped
cross section (Fig. 63 is extruded, which has been found to be
particularly adaptable to the edge 153 of the reinforced elas-
tomeric fa~ric 154 which is to be covered. Finally, it will be
noted that a flat recess at 155 has been ground in the forming
; plate 150 and a portion of the rod 152. As seen in Fig. 5, the
recess acts as a guide for the fabric 154 and is generally
employed in the pos~itioning of the extruder assemblies with
respect to the fabric for the application of the gum edgeO
slight clearance between the rod 152 and the fabric 154 may be
maintained when the reinforcement filaments are metallic in
order to pre~ent premature wear of the rod 152.
The end 157 of rod 152 extends along the outlet 149 a
distance sufficient to cause the extrudate to turn away from the
forming wheel 135 and dlrectly toward the fabric edge 153, the
flow:being indicated by the arrow B in Fig. 5. The turning of
~ the extrudate in:this manner helps significantly to force it
:~: into the fabric edge, between all of the reinforcing filaments
therein, without entrapment of micro air pockets.
At the underside of the lower half 144 of head 133 an
elongated~1at plate 15~ is attached which extends the length of
-15-
.
~ .
~37~i7
the head and a distance rearwardly thereof upon which the extru-
der head heat element 134 is carried which pro~ides heat to the
interior of the head 133. A short forwardly ex~ending foot 158
is welded to the leading edge 159 of plate 156 which carries a
longitudinally extending slot 160. The foot 158 is provided for
support of the forming wheel 135 which rests upon a washer 161
and spacer 162. A bolt 163 passes through a bore in the wheel
135 washer and spacer and slot 160 and is connected to a T-
shaped nut 164. Movement of the wheel 135 away~from the extru- -
der head outlet 149, along the slot 160, effectively increases
the space between the formin~ edge 165 of wheel 135 and the edge
of the fabric, as depicted in phantom in Fig. 5.
The flat plate 156 also serves as a mount for an arm
166 which pivotally carries a lever 167 (Fig. 1). ~t one end of
the lever 167 is mounted a rotatable wheel 168 which engages the
reinforcad abric drawn between it and the smooth plate 136. A
tension sprin~ 169 a~fixed to the other end of lever 167 and to
the arm 166 urges~the wheel 168 downwardly against the fabric.
The wheel 168 is preferably canted toward the extruder head 133
in order to urge the edge of the fabria firmly into contact with
the extrudate. A similar arrangement (not shown) is employed
with the extruder assembly 18.
During operation of the apparatus 10, the reinforced
fabri.c 154 is draun between the extruder heads 121 and 133 and
over the smooth plates 130 and 136 which are adju~ted to bring
the edges 153 o~ the fabric into approximately the same plane of
the forming edges of the wheels 129 and 135. To pull the
fabric, the drawing~mechanism~20, depicted in Fig. 8, is em-
ployed. The mechanism includes two rollers 170 and 171 mounted
~30 on a~pair of ver~ical supparts 172 aarried by the frame 11. The
:
~lower rolle.r 171 has a pulley 173 driven by a pawer belt 174
canneated~to a motor~175~. The~ tor 175 is mounted by a bracket
16-
,
33~
176, itself carried by vertical support 172. Counterclockwise
rotation of the roller 171 will advance the fabric 154 between
rollers 170 and 171 from the support table 12. ~lthough not
detailed in the drawings, it should be understood that the
rollers 170 and 171 may be adjustably spaced from each other to
accommodate varying thicknesses in the fabric.
Returning to the opera-tioIl of the apparatus 10, the
amount of elastomer extruded to form the gum edge 180 (Fig. 7~
is controlled, first, by the distance of the recess 155 from the
abric edge 153 and, secondly, by the distance between the
forming edge 165 and the fabric. By positioning the wheel 135
closer to the edge of the fabric than the width of the extru-
date, the elastomer i5 forced into exact engagement with the
fabric edge contacting substantially all of the exposed surfaces
thereof and particularly the reinforcement filaments, as de-
picted in Fig. 7. In this manner, virtually no air can become
entrapped between filam~nts, which has in the past permitted the
occurrence of some oxidation. Furthermore, total possible
adherence resultrs rom the close contact of the extrudate with
the fabric edge. Also, to be noted is that the edge 165 con-
stitutes a second forming surface which imparts a second,
.
extexnal edge to the extrudate as it is joined to the fabric.
Owing to the initial C-shaped configuration of the extruded
ribbon, it is seen that a portion thereof passes over and below
the fabric edge
In addition to building up elastomer to avoid hinge
points at the edges of belts~ and body plies, metallic reinforce-
ment 188, either cabled or single strand, is readily encompassed
by the gum edge 180 or edge of other suitable profile. The
apparatus 10 is partlcularly useful with reinforced elastomeric
fabric 154 comprising a plurality of narrow reinforced ribbons
189 severed from a continuously extruded ribbon and consecu-
-17-
3~7~
tively stitched together as may be constructed on an apparatusdescribed in the aforementioned U.S. Patent No. 3,803,965. On
such an apparatus, elastomeric fabric withdrawn therefrom will
be still warm from the extruder when it is fed across the table
12 of the apparatus 10. Moreover, the severed ends of steel
reinforcement need be exposed to the atmosphere for no longer
than approximately one minute prior to receiving the gum edge,
thus eliminating any possibility of oxidation which could give
rise to subsequent edge separation of elastomer from reinforce-
ment.
With reference now to Fig. 11, the alternate embodi-
ment, referred to generally by the numeral 210, shall be
described. The apparatus 210 has a rigid base frame 211 from
which is supported the primary mechanisms, i.e., means for
support of the reinforced elastomeric fabric 154, indicated by
the numeral 212, inboard and outboard carriage assemblies, 213
and 214 respectively and inboard and outboard extruder assem-
blies, 215 and 216 respectively.
The means for support 212 comprises a cylindrical
20 drum 220. A hub 221 is provided at each end and a drum shaft
222, affixed to the hubs and concentric with the drum 220,
enables the drum to rotate. The drum shaft 222 extends beyond
the length of the dr~um and is supported at the inboard end by a
saddle 223 carried by inboard carriage assembly 213. Although
the shaft could be journalled in a suitable bearing assembly,
the relative light~eight of the drum and slow revolution thereof
permits the use of a saddle 223 whlch in turn facilitates re-
moval of the drum as described hereinbelow.
At the outboard end of the drum, the shaft 222 is also
supported by a~saddle 224 and is further provided with a gear
225 which in turn meshes with a drive gear 226. The gear 226
-18-
3~797
is carried on a shaft having a pulley 228 about which is reeved
a drive belt 229 from a drive pulley 230. A motor 231, angle
drive 232 and gear reducer 233 are provided to drive the pulley
230 for the rotation of the drum 220. During operation of the
apparatus 210, the ~abric 154 is passed over the drum 210 and
rotation thereof enables the fabric to pass through the appar
atus in the direction of the arrow A'. Although a means for
rotating the drum 220 has been provided via gears 225 and 225,
motor 231 and related components, it is to be understood that
the fabric could be drawn through the apparatus 210 by other
means such as a conventional wind-up unit (not shown and not
forming a part of this invention) which draws the fabric into
rolls for subsequent storaye, shipment and use. Thus, the drum
220 need only be rotatable as the ~a~ric 154 passes thereover.
The carriage assemblies 213 and 214 are similar in
structure and function to the assemblies 13 and 14 described
herelnabove in conjunctlon with the apparatus 10 and therefore,
will not be discussed in detail. Basica~ly, the inboard car-
riage 213 i5 movabIe toward and away from the drum 220 a short
; 20 distance of 1-2 inches (2.5 - 5.0 cm) and reciprocal movement of
the outboard carriage 214 over bed plates 240 and 241 is per-
~ missible over a greater distance, e.g., 30 inches (75 cm~.
; Carried within the frame 211 of ~he apparatus 21C are
carriage shafts 242 and 243 provided with handwheels 244 and
245, respectively. Rotation of handwheel 244 reciprocates
inboard carriage assembly 213 while rotation of handwheel 245
: :
reciprocates outboard~carriage as~embly 214. The shaft 242 is
threaded and engages a block (not shown) extending From the
underside of the carriage assembly 213 for reciprocation,
similar to the blocks 65 and 68 described hereinabove. The
shaft 243 carrles a gear 246 me~hing with a geax 248 carried by
outboard carriage~shaft 249 which in turn threadingly engages a
: ~
-19 - ,
,
.: ... - . : ... . . .
~L3~
block (not shown) extending from carriage assembly 214. The
gears 246 and 248 are employed because the carriage shafts 242
and 249 are too close together to carry the handwheels 244 and
245.
The extruder assemblies 215 and 216 are also similar
in structure and function to the extruder assemblies 1~ and 19
of the apparatus 10. Each has an extruder screw driven by
motors (not shown~ carried within the frame 211. The extruder
assembly 215 includes the extruder 250, feed port 251, extruder
head 252, forming wheel 253 and heating element (not shown) as
does the assembly 216, having an extruder 254, feed port 255,
extruder head 256,~forming wheel 258 and heating element (not
shown)O For a detailed description o-f the remaining components
the exclusion of the elastomeric material, the formation of a
profile and the application thereof to the edge of the fabric
154l xeference to Figs. 5-7 may be made, it being understood
that the extruder assemblles 18 and 19 could be directly sub-
stituted for the assemblies 215 and 216.
:~ During operation of the apparatus 210, the extruder
assemblies are moved until the forming wheels 253 and 258 are
within a sl.ight distance :Erom the edges of the fabric 154, pre-
determined by the desired dimensions of the gum edges to be
applied. As depicted in Fig. 11, the fabric 154 extends slight-
ly beyond the edges of ths drum 220 in order to expose all
surfaces of the edge to the extrudate. In -the event it is
desired to edge fabrics of different widths, the drum 220 and
shaft 222 can be readily removed by vertically raising the same
from the saddles 223 and 224. Thereafter, another drum and
~shaft may be lowered onto the bloc~s with the gear 225 or
~ 30 another being af~ixed to the shaEt if rotation of the drum be
:~ desired.
:
:
~ 2Q-
'~ ~
'
,~ :
3 ~3~
As will be appreciated by those skilled in the art,
an expansible drum could be abricated and employed in lieu of
the removable drums disclosed herein, without departing from
the scope of the present invention. However, the greater the
simplicity of the removable drum and the reduction in the number
of mechanical members attendant an expansible drum results in a
more trouble-free apparatus. Of course, once the new dxum size
has been established and positioned, movement of the carriage
assemblies 215 and 216 will readily bring the extruders into
position ~or operation of the apparatus 210.
Thus, it should be apparent from the faregoing des-
cription of the preferred embodiment that the present invention
herein described accomplishes the object of the invention. The
apparatus and preferred method of operation thereof permit an
edge of substantially any extrudable elastomer,~compatible with
that of the reinforced elastomeric fabric, to be applied ~o at
least one and preferably two opposed edges in one pass. Owing
; to~the manner in which the elastomer is applied, air pockets
which could give rise to oxidatlon o steel reinforcement or
discontinuities between elastomer and reinforcement are elimi-
nated. Moreover, edges are applied in profiles heretofore
impossible or at least impracticable with conventional equip-
ment,~ and elastomers,~more desirable but prohibi~ively expen-
sive, or perhaps difficult to apply, may now be applied easily
and with little or no waste.
::
.
