Note: Descriptions are shown in the official language in which they were submitted.
~ 3~'~
The present invention ~ela~es to R ~lbber rnixture,
in which fibers are introduced, Eor producing solid rubber
tir~s~ and to a solid ~ubber tire produced therewith. The
tire is made of rubber or rubber~like elas-~omeric material,
and comprises one or more layers, wqth the fibers being
present in at least one of the layers.
The cost of producing a solid rubber tire is reduced
in a known manner by introclucing fibers into the rubber rnix-
~ures for solid tires, ~nd th~ thus procluced vulcanized
1~ goods are more rigid or harder The fibers are pla~ed in
various layers o the solid rubber t-Lres depPDding upon the
application oE the latter. With such solid tires, which
comprise a tread rubber9 a resilient rubber CUShiOIl, and a
base ring of tough-hard rubber, it is important especially
-for the base ring rubber, which may have skeel wire inserts
extending thereln 3 to provide an extremely tough~hard mix-
ture so that the tire, mounted for instance with a press
fit upon a cylindrical surface of the rim, maintains a
secure seat even during high loading thereof. Included as
20 mater;als for fibers ko be introduced for e~ery type of
solid tire are, for instc~nce, mineral fibers such as as-
bestos; synthetic fibers such as rayon7 nylon, polyeth~lene,
etc.; animal fibers su~h as wool; and plant fibers such as
wood. Metal, glass, and carbon can also be suitable.
It has been proven wlth Icnown solid tires having iber
particles placed iIl the base ring rubber, that the iber
particles begin to shift within the rubber mixture because
of the continuously changing loading during operation;
these fîber particles then d~mage the surrounding rubber be-
30 ca~se o this interior mo~ement, so that the rubber fre-
quently already after a short time becomes brittle (or
~lawed)~ thus endangering the seating of the tire on the
rim body.
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:~ ~7239~
It is therefore an obîec~ oE ~he pre~ent illvention to
provide a rub~er mixture for a solîd tire, and a solid tire
itself, with which a secure seating on the riln, and a re~
liable operation, are assured.
This object, and other objects and advantages of the
present invention, will appear more clearly from t~e fol-
lo~ing specification in connec~ion with the accorllpanying
drawin$, in which:
Figure 1 is a radial partial section of one embofliment
of a solid rubber tire according to the present inveDtion;
- Figure 2 is a fragmentary plan ~iew of a circum-
ferential surface at the level of line II-II iD Figures
and 3; and
Fi~ure 3 is a radial partial section of a further
embodiment of the inventive solid ~ubber tire.
By one aspect o~ this invention, there is provided a
solid tire of elastomeric rnaterial, comprising a~ least o~e
layer of the elastomeric material; and fibers disposed in
at least one of the layers7 the fibers being chemioally bond-
ed to surrounding elastomeric material by means of a bond-
ing systemO
By a further aspect of this invention, there is pro-
vided a rubber mixture for producing solid tires, the mix-
ture comprising elastomeric material, fibers embedded in
the elastom~ric material9 and a bonding system compatible
with the fibers and the elastomeric rnaterial.
The bonding system is advantageously introduced di-
rectly into the rubber mixtureO Due to the chemical bond-
ing between the surface of the fibers and the adjoining
rubber, the fibers are no longer present in the finished
tire as 130s~ foreign bodies in the rubber9 so that a
"sawing effect" can no longer be carried out b~ the fibers
during inner movements thereof; insteadl the fibers fo~n
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3 9 ~a r.igidly connectecl unit with ~he rubber~
Tough-hard rubber mi~tures of prev:Lously unattain-
able qualit~ for the base ring are attained with the present
invention, so that solid tlres produced there~ith have a.
considera~ reater durability ancl useful lie.
Pursuant to one specific embc)diment of the presen~ in~
vention, the conventional metallic inserts, e.gl steel ~,~re
cores, in the base rubber can be entirely elim:inated if
fibers with a proportional wei.ght: of at lcast 5% of the
~^.7eight of the base ~ing are introcluced at least in the base
ring rubber layer~ and i.E the lc~yer thiclcness of the base
ring rubber layer is from lV% to 90% of the eross-sectional
height of the tire. According to one preferred embodiment,
the thiclm ess of the base ring rubber layer is approximately
50% of the cross-sectional height of the tire.
This const~lction is ~ased upon the realization that
by embedding fibers in the base ring with a proport:ional
weight of over 5%, in conjunction with a minirnurn thickness
for the base ring layer, which depends upon the required
20 operational loading of the tire, such a good rigidity or
nardness is attained that the heavy c~nd e~pensive steel
~Lre cores cc~n be entirely eliminated. To achieve a re~
liable rim seating, the mounted tire should have c~n inner
diameter which, due to stretching, is about 0.5% to 10%
greater than in the non-mo~mted condition thereof.
The tire according to the present invention, asicle
from a considerable weight reduction realized by elimina-
tion of the steel wqre cores, primarily has the advantage
of a simpler and less expensive production.
A further advantage is the not inconsiderable re-
duction of resistance to rolling brought about primarily
b~ the increasecl rigidityO
Furthermore, the teaching of the present invention
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i.i~23~1
is especially suitable ~or increasin~ the st~bili.ty o
certain vehicles ~hich use solid tlres due to the bonded
placernent of fibers in the resilient rub~er cushion~
Technical advantages can e~en be achieved accord~ng
to the present invent:ion with soli.d tires having only one
rubber layer, or having two different rubber layers.
Referring now to the drawing in detai.l, the solid
tire is made of rubber or rubber~l.il.~e materials, c~nd
essent;ally comprises three layers, narnely a wear-resistant
tread rubber I, a resili.ent rubber cushion 2, and a b~se
ring 3 of tough-hard rub~er with or without steel wire or
band cores 4 embeclded thereing the latter extending in the
circumferential direction of the tire~
Fibers 5 are introduced in the rubber o the base rîng
39 and in the embodiment of Fig. 1 also in the resilient
rubber cushion 2, the fibers 5 are chemically bonded to
the adjacent rubber by means of a bonding system, which
can, for example, be the Icnown resorcinol/hexa (hexamethyl-
enetetramine) s~stem. The chemical bond is schematically
illustra-ted in the drawing by dots in the immediate vicinity
of the fibers 5.
The solid tire according to Fig. 3 differs from that
according to Fig. 1 in that the base ring 3 is enlarged to
approximately hal~ the cross-sectional height of the tire,
and is no longer provided with steel wire cores, further-
more, the bonded embedded fibers are located exclusively
in the base ring 3. Naturally, however, if required, the
fibers can also be provid~d in the other ~wo la.yers.
Also~ other thickness relationships in the range of between
10% and 90% of the cross-sectional height of the tire are
possible for the base ring 3; such relationships depend
upon the respective application or purpose o~ the tireO
The proportional weight of the fiber material 5 to
'J ;~
the total weight o~ the base ring 3 shoulcl ~e at least 5%.
Proportions i.n a range of l5C/o to 20% have proven to be
advantageous.
The use of previously conve~ltional steel wire cores
is no longer necessary with a sol'id tire having the charac-
teristics described in the forego-ing paragraphs; nonethe~
less, the possibility that the ti-re coulcl become loosened
from the rirn is not ignored. ~le tire is mounted by a press
fit upon a non-illustrated rim, with the inner dic~neter of
10 the tir~ being approxima~ely 015 ~o 10%, and preEerahly
approximately 5%, greater thc~n in the non~mounted concl.ition
o~ the tire to ach:;eve a preloading or prestressing for a
secure seating of the mounked tire. Further fastening Means
for a secure seating o:E the tire on the rim are then not
necessary.
Synthetic fiber material, for exarnple a mixture of
rayon and nyl~n, is preferably used or the fibers 5. It
is especially adv~ntageous to o'btain the fibers 5 ei~her
from scrap from the manufacture of tire cord fabr.ic7 or
2Q from the cord ~abric o:~ used tires~
The fibers 5 should have a length of 1 to 5 rnm, and
the aspect ratio (the ratio of the leng~h to the diameter)
should be at least 20~
The small or even cornminuted fibers 5, as well as
-the materials for the associated bonding system~ are added
to the rubber mixture prior to calendering, so that the
fiber particles 5, initially introduced in a non-oriented
or random manner9 are aligned or oriented during the
calendering process, prefera~ly in t'h~ direction of move-
30 ment of the rollers. Consequently, during manufacture ofthe solid tire, the fiber partic'les 5 are preferably at
least predominantly disposed in the circumerential direc-
tion~ so that an especially high rigidity or hardness is
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2 3 3 ~1atta-ined in the base ring 30
It sh.ould be notecl that l:f necessary the fiber
particles S can also comprise metallic mater:ial, so that
for example the brass~plated steel ~ires from used pneu-
matic tires cc~n be utilized~ Maturally, in sueh a si~la-
tion a Icno~l bonding systeril for brass and steel wou].d be
usedO
Fibers 5 of other mat~rials ean also be usedO In
eaeh case it is import~mt that to the assoeiated rubber
mixture a bonding system be added whieh effeets a strong
chemical bond between the selectecl :~iber material and the
adjacent rubber.
The aorementionecl introduction of fiber ~aterial
also into the resili.ent rubber cushîon ~ has proven
espeeially useul with solid tires whieh are providecl for
fork lifts having great lifting heights. In such cases the
stability of the vehiele is considerably inereased by the
bonded introduetion of fiber particles 5 into the rubber
eushion 2.
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