Iowa County democrat. [volume] (Mineral Point, Wis.) 1877-1938, 1910-02-10

and during one of these stages Of this
process the chemicals which 20 to
make the final vulcanized product
(the principal chemical Of which il
sulphur) are mixed with the gum. I,
| is these vulcanizing chemicals and
their proper proportions that institute
what really are genuine trade secrets
In the work of tire making.
From the mixing machines the
sheets or long bands of rubber are
taken to the calendering machines
composed chiefly of steam heated
rolls. A great part of the rubber
sticks to the rolls, but, strangely
enough, that part of which does come
out is very thin, smooth and even
strip of material, though of course
very sticky. By the adjustment of the
rolls these sheets can be made of anv
desired thickness.
In order to handle these delicate
and exceedingly sticky strips thew
are reeled off from the calenderine
rolls between sheets of. cotton cloth
Thus they are easily handled and
carried about and prevented from ac.
cumulating dirt When it is desired
It Is an easy matter to unreel these
rolls OF cloth and to separate the gum
from the cotton.
The same rolls are used for max.
ing fabricated rubber; that is. a kind
or canvas permeated with the rub.
Der gum, and having one side com
posed of the fabric and one side Of
rubber To produce this fabric icing
STRIPS OF the canvas coated on one
side with a cement are fed through
the rolls in such way that the rub.
Der gum, adhering to one is soueezed
down upon the canvas and caused r.
thoroughly permeata it, It is this Fab
rlcated rubber which is used in largo
part in making up the outer case or
snoes, of automobile tires.
In the hand made process thase
strips OF fabricated canvas. in which
the canvas is cut on a bias, are care.
Iuily laid by hand upon a cast iron
core, the purpose of the core heinz
10 give the correct shape to the tire
by main strength the operator draws
the FABRIC around the core using his
utmost endeavor to put uniform
stretch throughout the material as r.
IS drawn around. Several layers are
placed. one above the other, thus
building up the tire. During the pro.
cess OF building up the beading is nut
IN around the rim, which always ex.
ISIS In an automobile tire to assist In
fastening the outer casing to the rim
OF the wheel.
NOW there are machines that not
only make six to seven tires in the
same length of time required by hand
TO make one, but they introduce into
the stretching and laying on of the
Fabricated rubber with precision and
uniformity, SO that one tire is almost
sure to last as long as any other.
After leaving the machines the core
is removed and, with its fabric and
rubber covering, is placed in mould,
In which the application of pressure
to the two side squeezes the rubber
fabric tightly, the pressure required
being exerted by hydraulic rams.
While this pressure is being exerted
steam at about 275 degrees tempera-
ture is blown into the vulcanizing
vessel, and the action Of the heat
causes a chemical combination which
finishes the vulcanizing process.
The tire is now ready to receive
the outer coating of tread, which is
an extra thickness of rubber put
around the running surface of the
tire. The tread is made separately
OF built-up strips of rubber gum, and
Is vulcanized by process similar to
that described above. 1t is Joined
to the fabric part of the tire by means
OF cement and bound to the tire byl
means Of strips of cloth. Meantime
The iron core has been removed and
Its place taken in the tire casing by
what is known as an air bag, which in
reality is an inner tube that will hold
air under pressure
The next step is to take this band
aged tire to another steam tank.
where the vulcanization is completed
and the tire and tread are made
into one piece. The action
of the heat, of course. expands the
air in the wind bag, and after all tne
stretch has been taken out of the wet
bandaged cloth the expansion of the
air in the wind bag puts a very heavy
pressure on the rubber of the casing
and tends to knit the parts firmly to-
sether.
The inner tubes are simply made
and their production is at present al. |
most entirely by hand work. The rub
per coming from the calender presses
s cut into the proper width and the
edges, after being scarfed, are over.
appel upon each other and cemented
n such way as to form one piece OF