Note: Descriptions are shown in the official language in which they were submitted.
20S787~
hETHOD FOR RECaVERING MET~L RE~NFORCErENT ~RU~
RUBBER TlRES
Field of the Invention
The invention relates to processing of worn
or rejected rubber articles~ and more
specifically, it deals with methods for recovering
metal reinforcement from ru~ber tires. The
invention-may be used at regeneration and t~re
retreading plants and at rubber manufacturing
plants.
/-~tate of the Art
Known ~n ,~he art is a method for recovering
metal reinforcement ~rom rubber tires invol;ving
heating metal reinforcement to a temperature of
f u5i on of the nearest rubber layers and separ~ting
the reinf~rcement from rubber ~SU~ A~ 10397~5~.
In carrying out this method a tire being
processed is clamped between power supply grippers
before heating sim~ltaneously with cuttin~ with
the grippers at outer and inner sides of its beads
to expose metal reinforcement.
The disadvanta~e of the prior art nethod
resides in high power req4irements because of the
need to heat to a temperature of rubber meltin~
nver the whole perimeter of reinforcement through
the whole thickness of r~bber, i~e., between metal
... .
reinforcement and the surfa~e of the tire. In
addltion, the method is defLcient because lt
- 30~ re~uires a continuous line of metal reinforcement,
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i.e'.~ this method is only suitab'le ~or recovering
bead rings from the tires and cannot be used for
recovering individual reinforcement members such
as metal. threads of the breaker so that the
capabilities of this method are limlted.
5ummary of the Inv~ntion
The inventior i5 b~sed on the problem of
providing a jfmethod .for recoverinq metal
reinforcement 'from rubber tires, wherein a lDcal
heating only and subsequent indir'ect heating of
the tire al low the capabilities 'of the method to
be enlarged~ ;
This problem i~ ~olv.ed by the fact that in a
method for recoverinq netal r~inforcement from
lS rubber tires, comprising placing a tire with metal
reinforcement into a high-frequency
electromagnetic field, heating and separating the
reinfarcement from rubber~ according to the
invention, a local pnrt~ on of the tire is clamped
between at least two pairs of pressure rolls, this ~
portion is heated to a temperature of pyrolysis of
.rubber layers n~arest ta the; reinforcement and
until a pyrol y5i 5 swellingj with' subsYquent
drawing of the tire between the rolls~
Heatiny only a lpcal partion of. metal
reinforcement to a temperature of pyrol y5i S of
rubber layers nearest thereto allows power
requirements to be lowered and capabilities of the
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2~5787~
method to be enl~rged ~n comparison with the state
of the art method for the following reasons.
A pyrolysis swelling~formed upon heating of a
local portion functions as a thermomechanlcal tear
S hetween layers ,of metal re~nforcement and rubb~r
The 5wel 1 i nJ is assoclated with metal
reinforcement which funct~ons as a heat conductor.
Mbving this thermomechanical tear along the whole
circle of the tire allows indlrect heating of the
tire to be carr~ed out without electric ener~y
consumption, and heating can be performed o~ both
. individual reinforcement members (metal cord
threads of the breaker) and continuous
reinforcement ~bead rings).
Drawing the tire between the rolls ls
preferably carried out by causing the tire to
rotate with respect to the rolls to facilitate the
process.
Brie~ Descriptiwn of the ~rawings
Z0 The invention will now be described in detail
with reference to the accompanying drawings
illustrating a method far recovering reinforcement
from rubber tires, in which~
Fig. I schematically shows ~n aDDaratus ~r
carrying out a method according'to the inventioni
Fig. Z i5 ditto~ a top view;
, Fig. 3 show~ a structure ~f a dismemberéd
tire.
20~7870
,.
Pref erred Embodiment of the Invent,ion ,
- Figs. 1 and 2 shQw -a tire l Which i ~
processed in an apparatus for carrying out a
method accbrding to the invention. the apparatus
S has a mechanlsm for rotating tire l which consists
of two pairs Z a~d 3 of pr,essure rolls. Pair 2 of
driven ~o~ls consists of a driven roll 4 and an
idle roll 5 and pair 3 of- pressure rolls cons~sts
of a driven r~ll 6 and an idle roll 7. Driven
10 : rolls 4 and ~ are connected to each other ~y means
of a drive shaft 8 and a chain drive 9. ~n
- inductor lO is provided between pairs 2 and ~ of
driven rolls. The apparatus also has longitudinal
circular knives 11 and 12 and a t~ansverse
circular kni~s l~ for subsequent cutting ~f a
- tire~ It will be apparent to those skilled in the
; art that any other known .devl ce such as a milling
; cutter can al 50 be used for the same purpose.
~ method for recovering metal reinforcements
".
from rubber tires~ e.g., metal cord threads of 'a
breaker is carried out in'the following manner.
Tire l (figs. 1 and ~) i5 fixed between p~irs
2 and 3 of pressure rolls ensuring reliable
. clamping ~f the tire an~ friction engagement
therewith at the ends of a local porti on ~ of the
tire. The length af this portion depends on the
tire size. In addition, pairs 2 and ~ of pressure
rolls ens~re sealing of the portion A along the
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20S7870
e ~r Q~ Ct ~ith {:h~ tir~. Ind~tor 10~
is inst~lled ~mm~diAtely adjacent ~o the s~rf~ce
of the tread layer of th~ tire in the zone of the
portion A, is then energized. ~ddy currents ~re
thu~ induced in a breaker 14 ~Fig. 3) which
consists of individual metal cord threads t~ heat
the threads. High-~requen~y inductlon eddy
currents mainly concentrate on the surface o~-the
metal cord threads. ~eating of rubber l~yers
~0 nearest to the breaker occurs from the surface of
breaker 14 through heat transfer~ Durin~ this
heating metal cord threads are gradually separated
from r~bber of a tread lS and ~ar~ass 16. The
metal cord threads of breaker 14 are heated until
rubber layers nearest thereto reach a temperature
of pyrolysis (thermochemical decomposition into
components with release of pyrolysis gases. This
process occurs without air supply. Pyrolysis gas
which i5 thus released forms a 'pyrolysis sw~lling
17 (bubble) between layers which finally ~trips
breaker 14 ~ff tread layer 15 and carcass layér
1~. The above-mentioned pyrolysis swelling 17
gets the farm af a cushion having its horizontal
axis aligned with the basellne of breaker 14~ the
2~ swelllng being formed onleither side of this line.
It should be noted th~t 5i nce heat conductance is
about 100 times a5 grea~ as heat conductance of
rubber and pyrolysis ~as at high temperat~re
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~about 600C is present in pyrolysis swelling 17,
withdrawal of thermal energy from the zone of
pyrolysis welling 17 occurs through m~tal cord'
threads (f.unctloning llke a heat conductor? in all
directlons away from the heated areA ~pnrtian ~)
between pairs 2 and 3 of pressure rol 15. The
layers of rubber whlch cover the metal cord-,are
r~l t~ ls fuslon of rub~er ~ayers ~hl~h are
nearest to the rubberized.metal cord threads at a
certain distance from the.local ~ortion ~.
Inductor 10 is then deenerglzed~ the
mechanism for rotatlng ti,re 1 is turned on~ and
' two pairs 2 and 3 of pressure rolls are used f~r
positivelv rollin~ tire ~ ~etwP~n ~h~ roll -
Pyrolysis swellina 17 cl~mDed betw~nr ~ e~al~d
by pairs 2.and 3 of rolls moves around tire 1 at a
el7ood ~hich c-n~-roc to:~,r of s~ft~ne~ rubb~ ~Y~-
~hi~ ~rr n~re~t to the metal parts. lt will be
~pl~aront to th~ce:l sl~; l l sd in th~: crt ~h~l. LIIC
speed of rotation of tir~ 1 i5 S0 chosen as to
h~ve enough time for transmitting thermal ,energy
through metal cord parts,;into zones outside the
portion A. As a result of full revolution o'f tire
25' 1 complete internal separation of the tire occurs
into tread layer 15 and carcass layer 16.
Longitudin~l circular knives ll and 12 are used t~
cut tire 1 along ring borders of the baseline of
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2~5787~ `
breaker 14. Tread layer lS, breaker 14 and
carcass layer 16 which are no more bound to ~ne
another are then easily separated.
The bead rings and metal cord threads are
removed from the tire.
The above-deseribed method allows metal
rein~orcement to be recovered from rubber tires at
a low cost.
Industrial ~pplicability
The method for recoverin~ metal reinforcement
from rubber tire~ may be used for processi-ng worn
tires at regenerating and retreading plants and at
rubb~r manufacturlng plant~
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