Note: Descriptions are shown in the official language in which they were submitted.
83~1~
Thls inventlon relates to a method of making a plastic or a fila-
ment or strand reinforced tire and to said tire. More particularly, this
invention relates to a method of making a reLnforcing member or preshaped
member of a tire having a single or multiple ply construction, to said con-
struction, to said component and tire, as well as construction of an elasto-
meric matrix to support the reinforcing component.
It has been the desire ldeally of the tire designer and builder to
build a tire using essentially the fabric and rubber precursors to thereby
eliminate the steps of spinning and shaping the fabric and/or compounding and
- 10 extruding, and cutting the rubber as well as the elimination of the conven-
tional tire building steps.
Therefore, an object of this invention is to present a method of
building a fabric reinforced tire that permits this ideal to be more nearly
; approximated.
-` The invention provides a method of building a tire comprising mold-
ing first and second plies having strands of desired bias angle, placing each
ply in a tire mold in the desired spaced relationship relative to the tire
mold and the other ply, positioning a bead portion of said first ply in a
corresponding recess of said second ply to lock the plies together, filling
the space between said plies and the mold when closed with an elastomeric
precursor, and heating to set the precursor around each ply to give a cured
tire when removed from the mold.
The nature of this invention can be more readily understood by
; reference to the drawings wherein Figure 1 is a perspective view in elevation
of a mold for molding the fabric or filanlent composition to form or shape a
ply of a reinforced tire.
Figure 2 is a partial cross-sectional view of the mold of Figure 1
along line 2-2 showing the fabric or filament component or ply in the cord
; path direction. Figure 3 is a partial cross-sectional view along line 3-3
showing the detail of the grooves for forming the cords in the crown of the
mold. Figure ~ is a plan view of a fabric ply showing the detail of the
fabric and means for molding filament in a unitary body. Figure 5 is
partial view of two fabric plies
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w-lth the beacl of` one posi-tioned and resting in a ma-ted re-
lationship inside -the recess of' the bead section of the other
ply. Fig. 6 is a cross~sectional view through the finished
tire. Fig. 7 is a cross-section through a curing press in
closed position. Fig. 8 is a cross-section through a curing
press in the open posi-tion showing the cured tire ready to
be stripped from the mold. Fig. 9 is an enlarged cross-sec-
; tional view along -the cord path of one embodiment of the
first ply. Fig. 10 is an enlarged cross-sectional view
along the cord path of one embodiment of the second ply. Fig.
11 is a perspective view in partial section of a tire hav-
ing the preshaped unitary reinforcing member positioned in
the tire. ~ig. 12 is a plan view of the reinforcing strands
in the preshaped reinforcing member for a tire. Fig. 13 is -
a partial enlarged view of Fig. 12. Fig. 14 is a cross-sec-
tion through a mold for forming a split type preshaped rein-
forcing member. Figs. 15, 16 and 17 show various methods of
mechanically fastening or locking the plies or also the ends
of the split-type preshaped reinforcing members together.
Fig. 18 shows a cross-se~ion through a tire-wheel
assembly where the preshaped rein~orcing member in the bead
area is joined integrally with the tire rim to achieve a
- unique tire-wheel assembly. Fig. 19 shows another embodi-
ment of tire-rim assembly where the tire has the contour of
some of the more recent tire designs.
Referring specifically to Fig. 1, numeral 11 identi-
fies the bo-ttom half of a ply mold and numeral 12 identifies
the top half of said ply mold. The top and bot-tom halves
are shown in Fig. 1 in mated relationship with ports 1~ po-
., ~ . . .. . .
3~6
sitioned for injecting in the material to form the molded
fabric reinforcing member and a:n exhaust or vacuum port 15
is shown positioned on the outside circumference of the mold
to facilitate removing air and obtaining the desired inert
gas blanket or vacuum within the mold. I-t should be appre-
ciated that the inlet and outlet ports 1~ and 15 respectively
will be placed around the mold as needed to facilitate f'ill-
ing the mold. Also, in Fig. 1 is shown a collapsible core
16 having segments 17, 18 and 19, etc. which permits the m~ld
easily and quic.kly to be opened and the fabric ply to be re-
moved. Balloon filling of the mold and top venting reduces
the tendency for bubble formation.
The nature of the new ply more readily may be under-
stood by raference to Fig. 2 where the molded cord or fab-
ric 20 is shown having bands 21 and 22 for holding the indi-
vidual parts, viz. filaments in the desired rèlationship as
the plies are removed from the ply mold and placed in the
mold for forming a tire. The tie bands 21 and -22 also form
another useful function as they all tend to give the plies
the desired spacing withi.n the tire mold and thus will reduce
the amount of friction between one ply and another ply.
I-t should be noted that the individual cords in the
ply terminate in the bead section 23 ancl that in the first
ply the bead section is notched to receive the ridge molded
into the bead section of the second ply which may be more
readi.ly seen and appreciated in F'ig. 5 whe.re thé ridged bead
of the second ply 25 rests within the notch~d bead of the
fir~-t ply to thereby allow the two plies to res-t in a uni-
tary relationship to form the unitary bead sec-tion 26. Thus~
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by -this mec~s of construc-tlon i-t is posslble -to form the cord
plies per se by injecting the cord forming material into -the
inlet ports 14 to fill the grooves 27 more clearly shown in
Fig. 3. When the grooves 27 of the mold have been filled
and the filament-forming ma-terial se-t, the fabric may be re-
moved from the mold by opening the mold to give a ply having
the details more clearly shown in Fig. 4.
It should be readily apparent that it is possible to
form plies with a cord path having either a right-hand or
left-hand relationship where the first ply is formed in a
mold having a cord path tha-t gives a cord having a left-hand
bias or left-angle configuration and the second ply is form-
ed in a mold having a right angle or bias configuration.
This invention is readily amenable to use of any cord
," 15 pa-th~ as well as use of reinforcing breakers and use of any
bead shape or combination of materials whereby the tire de-'
sign can be moided precisely as de~ired by the designer, for
example, as shown in Figs. 12~ 13 and 14.
When the desired number of plies have been formed,
' 20 then the plies are placed in the mold and the tie bands 21
- and 22 hold the plies away from the,mold and in the desired
', spaced relationship. The plies in the mold can be formed
into a tire by suitable injection of elastomeric material to
give a tire having the cross section more readily shown in
~, 25 Fig. 6. The tire mold ùsed in forming the tire using plies
formed in the manner described,in accordance with this in-
jection method may be more readily understood by reference
-, to Fig. 7 which shows -the closed mold having the plies plac-
ed in position and ready to receive a suitable injection of
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rubber material to form the sicLewall and tread sec-tion as i-t
would be familiar to those of ordinaIy skill in the art. Re~
ference to Fig. 8 shows the mold in -the open position ready
to permit the molded tire to be removed from the mold to
give a tire having the cross section shown in Fig. 6
The material used to form the cords or plies of this
invention are broadly of the thermoplastic thermosetting
type which may be melted and injected into the ply mold
through the ports 14 and then be set or solidified to give
a ply that can be removed~ and the material has become ther-
mosetting in nature after the molding. The preferred ma-
terials for forming the plies of this inventlon are the poly-
amide resins and the polyester resins. In the polyamide re-
sins it is specifically desirable to utilize li~uid lactams
containing the desired catalysts and promoters which may be
injected in the ply mold or unitary preshaped reinforcing
member and then be polymerized and set to give a finished
nylon fabric ply or preshaped reinforcing member. The na-
ture of this art is readily understood and more particular-
ly described in the patent art by United States Patents
3,448~085 and 3,017,391. Also~ specifically preferred is
the higher melting polyamides such as those available under
the name '1Kapton" from E. I. duPont deNemours & Company~ as
well as the polyimide type resins or Milar type polyesters.
Representative of the many polyesters that, are used
for tire cords is the terephthalates of ethylene glycol and
copolymers of terephthalic acid with phthalic and isophtha- -
; lic acid. These materials having suitable intrinsic vis-
cosity may be melted nd in~ected into the cord mold to
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form the tire ply. It ls also desirable that -the various
well-known techniques such as :Lntrinic viscosity jumpers be
used to further enhance the viscosity to give a polyester
that is less readily melted and having improved heat charac~
teristics. Thus, it is prefer:red the polyesters or poly- .
amides, for instance, become thermosetting in nature after
the molding operation.
Once the tire ply has been formed and placed in -the
. mold the ply may be covered with an elastomeric ma-terial
such as the liquid polyurethane reaction mixtures or those
so-called encapsulated rubber dispersions in a suitable ex-
: tender oil which when injected into the tire mold and heated
to the cured temperature, cures to give essentially a homo-
-. geneous elastomer. The nature of these elastomeric mate~als
: 15 and their preparation are well .known and illustrated in the
following recent patents: Canadian 860,084 and Fr~ench 1,
.~` 526~o75.
- EXAMPLE I
A ply mold of the type shown in Fig 1 and related
::~
:: 20 drawings is con~ected to a pressurized extruder by ports 14
~ and a vacuum of 5 p.s.i. (pounds per square inch) pulled on
.. ~ ports 15. The extruder is charged with a molding grade poly-amide Kapton, a trademark of E. I. duPont deNemours & Com-
pany, and worked as the temperature of the extruder was suf-
` 25 ficient to permit the Kapton as a semi fluid-to-fluid mix-
............. ture to be ~orced into the cavity of the ply mold to fill
the grooves thereof. The mold is cooled below melting point
of the polyamide to solidify the polyamide in the cavity so
the ply could be removed when the mold is open. .
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A second ~ is molded in lik~ ;-r!anner. Preferably
i ~ the first ply is molded in a mold t~ gl a the filament a
left-hand bias and the second ply is ~ Lded in a mold to give
its filaments a right-hand bias. The plies are then placed
in the mold to cause the bead of the second ply to nest in
the bead of the first ply in -the manner shown in Fig. 5.
With the plies positioned in the mold, the mold is closed
and an elastomeric tire extruded around the plies by inject-
;`
ing suitable fluid elastomer or elastomeric precursor into
the mold to fill it.
Satisfactory fluid elastomers for this purpose are
those shown in Examples A and B as well as the other examples
of French Patent 1,526,075~
, . .
The ~ollowing examples are given by way of illustra-
tion but not limitation of the many elastomers and elastomer
precursors known and useful in this invention, and all parts
are expressed in weight, except for contrary indication.
Example A:
- This example illustrates the method of applying a
~; 20 surface film to rubber particles mixed by spray drying, and
the formulation of a fluid mixture with two phases by dis-
persing the spray dried particles in a dispersion liquid.
A solution in hexane of a polybutadiene containing
about 15 percent polybutadiene is mixed in solution by mix-
,,
ing, with agitation, with the following mixture ingredients:
- Polybutadiene 100
Carbon black * 68
Zinc oxide 2
Stearic acid 2
o Antioxidant 1.5
Sul~ur 2
Accelerator
Total 177
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*Furnace black of hlghly abrasive intermediate grade.
The fluid mixture is adjusted to a total content of
solids of 20 percent by evaporating excess hexane which rnay
have been added as a vehicle for some pigments.
A certain amount of the above mixed rubber mastic is
emulsified in an aqueous 10 percent solution of polyvinyl
alcohol (Elvanol 50-42 which is a trademark of E.I. duPont
deNemours ~ Company and which is composed essentially of
polyvin~l alcohol and esterified derivatives), by using a
sufficient amount of this latter to provide one part of poly-
vinyl alcohol per 3 parts of compounded rubber ~that is~
polybutadiene pluspignents)0 An Eppenbach homogenizer or
equivalent high shearing assembl~ to carry out the emulsifi-
cation of the compounded rubber mastic and to produce small
particles having a diameter essentially between 1 and 30 mi-
.~.
crons. The polyvinyl alcohol serves as colloidal stabilizer
for the system of particles,`and subsequently as barrier
. .,
around the spray-dried particles. The hexane is evaporated
` from the sys~tem with stirring~ in order to leave a s~stem of
compounded rubber particles~ A certain amount of water is
- - removed wlth the hexa~e, but is replaced to provide a total
final content of solids of 20 to 25 percen-t.
The aqueous dispersion, free from hexane, of the com-
pounded rubber, is spray dried to obtain fine particles of
- 25 compounded rubber coated with pol~vinyl alcohol, the ratio
- of the weight of the rubber to the coating being 75:25. The
; particles obtained in this manner are mixed with a rubber
diluting oil of the paraffinic type in the proportions of
about 60 parts of oil per 100 parts of particles in order
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to form a ~luicl rubber pas-te. The mix-ture remains fluid at
ambien-t temperature so it can be made to flow into a mold
~ cavity, where i-t can be subjected to a -temperature of 143C.
s in a hydraulic press for 60 minutes. The initially fluid
: 5 rubber composite is -transformed into a solid and firm vul-
canizate.
The product of Example A can be varied to obtain ~a
range of values of the ratio of the polyvinyl alcohol to the
rubber, by varying the resistance of the encapsulated par-
:
ticles to the oils and to -the plasticizers used as li~uid
component of the rubber composition in two phases. For
example, the thickness of the coating may he reduced so that
, the ratio of the rubber to the coating is 97:3. The s-torage
time of the fluid rubber composi-tion thus varies within a
wide time range.
The product may also be varied in regard to the poly-
meric film-forming material used to apply a coating to the
particles. The materials soluble in water or capable of
being dispersed in water tha-t may be used are gelatin, gum
arabic, a copolymer of styrene and maleic anhydride (for
example, "Lytron" a trademark of The Monsanto Company), co-
polymers of methyl and vinyl ether and maleic anhydride (for
~ example 7 "Gantrez", a trademark of General Aniline & Film Cor-
;~ poration), methyl cellulose, hydroxyethyl cellulose, poly-
vinyl pyrrolidone, a dextrin, a carboxylated dextrin, block
` copolymers containing hydrocarbon polymer blocks and polye-ther
blocks such as polyethylene oxide, block copolymers of dif-
ferent alkylene oxides, polymers and copolymers of acrylic
acid and numerous other materials.
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The formula for vulcanlzing the rubber may be varied
a-t will to give those propert:Les well known to the rubber
compounder.
The product may again be modified in regard to the na-
ture and the amount of liquid dispersion agent in which the
; encapsulated particles (surrounded by a barrier layer) are
put in suspension. The liquid dispersion agent may be used
~- in amounts between 25 and 150 parts per 100 parts of parti-
cles. The liquid dispersion agent may be any Or the classic
irubber diluting oils or mixtures of these, with or without
supplementary amounts of other liquids to increase or dec~ease
the viscosity or adjust the characteristics of the fluid
rubber in another manner.
Plasticizers of the ester type (mono- and poly-esters),
polyglycols, ethers and formals may be used. It is usually
desirable to adapt the liquid dispersion agent to the ma-
terials of the surface film of the particles, or conversely,
so as to obtain a satisfactory resistance time of the par-
~ ,.
ticles to the diffusion to their interior of the liquid dis-
-
persion agent.
Example B:
A solution in hexane of a polybutadiene containing
about 15 percent polybutadiene is mixed in solution by mix-
ing it, with stirring, with the same compounding ingredients
as those used in Example I or with other suitable vulcaniza-
tion ingredients. The liquid mixture is adjusted to a total
solids content of 20 percent by evaporating the excess he-
xane which is added as the vehicle for some pigments.
. . ,
A certain amount of the above mixed rubber mastic is
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emulsifled in an aqueous solll-tion with 10 percent of a gela-
tin (super-clarified "Atlan-t:ic" gelatin of -the A, low Bloom
type, a trademark o~ A. M. Look Canning Company) by using a
sufficient amount o~ this latter solution to provide one part
of gelatin per 2 parts of co~pound rubber (that is, polybuta-
diene plus pigments). An Eppenbach homogenizer is used to
emulsify the liquid mastic. The gelatin serves ini-tially as
stabilizer for the colloidal system, an~ later as barrier
around -the rubber particles.
The hexane is evapora-ted from the system by agitating,
for example, in a disk, concentra-ting apparatus o~ the type
used to increase the total solids content of the latex. A
part of the water is removed with the hexane, but it is con-
tinuously or intermittently replaced to maintain the to-tal
- 15 solids content between 20 and 25 percent (compounded rubber
plus gelatin).
The micro-encapsulation of the rubber particles is
carried out in the following manner: the hexane-free dis-
persion of compounded rubber particles in solution in gela-
tin which is obtained is taken to 50C. and subjected to aseparation of the gelatin on -the rubber particles, the co-
acervation being effected by slow addition of L~60 cm3 ap-
proximately of an aqueous solution with 20 percent sodium
sulfate to about 1150 grams of this dispersion of rubber
particles in solution in gelatin at 50C. by s-tirring con-
tinuously. The gela-tin is hardened around the rubber par-
ticles at a lower temperature by pouring the mixture with
s-tirring into 2.08 li-ters of a 7 percent solution of sodium
sulfate between 0 and 10C. and by maintaining the tempera-
ture at this level. The encapsulated particles are washed
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by allowing them to settle in the aqueous system maintained
between oo and 10C., by decanting the supernatant aqueous
phase, by adding a supplemental amount of cold water (0-10C.)
and by dispersing the particles. This series of opera-tions
may be repeated several times. The final dispersion of rub-
. ~ ber particles coated with gelatin may be dried by spray dry-
ing to isolate them. Also~ they may be treated with formal-
dehyde to harden the capsule surrounding each particle, on
which the particles may be recovered by filtration or by
spray drying. Any previously mentioned process of coacerva-
~-~ tion may be adopted to deposit a film around rubber particles,
and any process for recovery of the particles coated with a
film by coacervation may be used in place of that described
more particularly in this example.
`- 15 The dried encapsulated rubber particles are mixed with
;~ .
~ a plasticizer such as a rubber diluting oil to form a fluid
~.
- mixture, which may be used in tire molding operations and
then be followed b~ a heating to form vulcanized rubber pro-
ducts.
In another embodiment~ the fluid elastomeric precur-
sors are chosen and compounded preferably to be those well
known to the rubber compounder as tread stocks and carcass
;~ stocks. Then the fluid tread stock is injected into mold
~ 28 through tread injection ports 29 and the fluid carcass
.
stock is injected into the mold through carcass injection
ports 30. The cured tire, which has been heated to curing
- temperature 250-3500F. is then removed from the open press
mold 31 of Fig. 8 to give a finished tire 32.~ Reference to
Fig. 6 shows the tread 33~ preferably of a speclally com-
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pounded tread stock of high ci~~ polybutadiene and a carcass
rubber 34 enveloping the plles and terminating in a bead foot
35-
Referring specifically to Figs. 11 and 12, another
embodiment of the invention is shown where the numeral 36
indicates a unitary preshaped reinforcing member. This uni-
tary preshaped reinforcing member has a bead area 37 having
a series of continuous radial strands 38 extending upward
therefrom to the tread area 39. As the strands ent2r the
tread area, they may have a criss-cross appearance to form
a criss-crossed pattern 40 in the tread area. In Figs. 11
and 12 this pattern is sho~n as essentially trapezoidal or
more precisely as a rectangular or diamond pattern 41 of
equal sides. This criss-cross pattern with the radlal st~ands
form essentially a belt design in the tread area and thus in
one aspect, the tire could be said to have a belt design in
the tread area. It should be appreciated that any network
of fabric reinforcing can be obtained by this invention. For
example, by controlling the angle of branching of the strands
a rectangular or square pattern can be obtained in the tread
to give a belt-type reinforcing member. Especially is this
so where the cross~sectional dimension of each strand is
varied to give a high degree of strength in one direction
or flexibility in all directions or in a single direction.
For instance, the strands running axially around the circum-
ference of the tire could be varied to give a thickness
several times that of the widtha or vice versa, to achieve
- the desired strength and flexibility in the desired direc-
tion. This is a feature not readily, if at all, obtainable
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in -the conventlonal woven fabric networks. Al~o, the strands
can be varied from trapezoldal in cross-section to essential-
ly circular or elllptical to give the desired degree of
strength and flexibility in plane and direction desired as
the tire is operated.
In Fig. 13 a preferred method of changlng the chord
pat-tern is shown in greater detail with the chords 38 run-
ning in a radial manner from the tlre bead 37 through the
sidewall area L~2 and then changing into a two or more ply
bias angle chord pattern. This is achieved by having the
individual strands 38 at the juncture 43 changing into a
wishbone shape or design to give the bias strands L~4 and 45
specifically in the tread area. As the bias strands cross
each other they can form various patterns as shown by numer-
al ~6, where the pattern is diamond shape. Use of the wish-
bone strand effect permits the degree of flexibility and
stiffness at the junction line ~7 of the sidewall and tread
..... . .
to be controlled to thereby control the tread reinforcing
thickness and tread wear in the first 48, second L~9, third
50, etc. tread ridges formed by grooves 51. Also, the de-
gree of curvature 60 in the junction ~3 can effect the tear
and flex life of the tire. Therefore, it is preferred that
sharp angles be avoided. It should be readily apparent that
this mode of forming the preshaped reinforcing member pro-
vides a method for obtaining a tire where internal reinforc-
ing can be bias, bias belted, radial belted or radial ln
the carcass area and bias in the tread area, to thereby per-
mit properties to be optimlzed in the tire from the bead to
the tread of the tire. In effect, any chord pattern can be
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achieved even to a network where strands essentially become
sheets with a network of holes which are essentially circu-
lar, depending on radius of curvature at the junction lines
47-
Since the above described preshaped reinforcing mem-
ber is cast or molded as a single piece, the mold will need
to be of the sectional type, which can be removed through
the torus circle 52. Therefore, in some instances, it would
be preferred to mold or cast the preshaped reinforcing mem-
ber in two halves 53 and 54 respectively, as illustrated in
Fig. 1~. Then these two halves can be fastened together in
their end areas 61 by suitable methods such as the mechani-
; cal fasteners shown in Figs. 15, 16 and 17 to give a unitary
preshaped reinforcing member. Alternately, the ends 61
could be fused together or cemented together to give the de-
sired unitary desîgn. Then the unit can be placed in the
; mold and be encapsulated in elastomer to give a finished
~; tire. Also, Figs. 1~ 15 and 16 share some of the many ar-
~` rangements. The ends 61 can be molded and yet be joined to
give a unitary preshaped reinforcing member having the torus-
configuration of a tire.
This invention in one of its embodiments is especial-
- ly well adapted for making tires for use with run-flat de-
vices. This aspect of the invention is best illustrated by
reference to Figs. 18 and 19 where the numeral 62 identifies
a two-piece wheel assembly. The two-piece wheel assembly
preferably comprises two wheel halves 62a and 62b respec-
tively, shown in this embodiment bolted together in this
assembly wi~h the wheel by bolts 55. The rim portions
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62a and 62b can be bolted onto the vehicle axle having an
o-ring 57 therebetween to give an alrtight seal. The rim por-
tions 62a and 62b can be placed in a suitable mold for form-
ing the preshaped reinforclng member and have the reinforcing
material adhered to the rim portions in the area 56 with the
preshaped reinforcing member 58 extending ~rom the rim por-
- tions to give a preshaped reinforcing member permanently
fixed to the rim portions. An adhesive material for rim por-
; tions which can be metal or fiberglass reinforced polyester
can be used advantageousl~ to aid ln bonding the rim por
tions and reinforcing member. Thus, when the preshaped
reinforcing member 58 is encapsulated in elastomer a tire is
~- obtained already mounted on the rim.
Since the rim portions are separate in the curved a~
59 they can be pulled apart prior to or during mounting to
` position the o-ring in position and to permit attachment,for
instance, by bolts~ to the wheel assembly to give a tire
mounted on a wheel~
Also~ it should be appreciated a disc, wheel-type or
- 20 tire-type run-flat device of the well-known design could beadded. A wheel-tire assembly of this type has the advantage
the tire and rlm are a unit, and thus the problem of main-
taining bead rim seating is avoided~ as well as lateral sta-
bility is improved, and the cost of mounting is eliminated.
. ;
Fig. 19 shows how tires having an unusual shape or
configuration can be made ver~ readily with this invention.
For instance, the preshaped reinforcing member 58 is formed
in the preferred embodiment adhered to the rim flange ends
63. Then this preshaped reinforcing member 58 with the rim
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port~ons 56 can be placed in a mold and encapsulated with
elastomer as shown by 64 in Fig. 19 and thus provide a tire
of the shape shown where the clistance ~rom tread to rim is
much less than the tread width. Also, this configuration
permits the tire to be in compression as well as tension
when fully inflated by the valve not shown.
While certain representative embodiments and details
have been shown for the purpose of illustrating the inventlon9
,~ it will be apparent to those skilled in this art that various changes ~nd modifications may be made therein with-
out departing from the spirit or scope of the invention.
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