or relating to the Treatment оr bber.
Year: 1898

page_text: Паргоѵещениз ш or relating to the Treatment оr bber.
A communication from BERTRAM GEORGE WORK, Manufacturer, of Akron, Ohio,
United States of America, and JOHN FULLERTON PALMER, Manufacturer, of
133, So. Clinton Street, Chicago, Illinois, United States of America.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :—
This invention relates to an improved process of treating india-rubber for the
purpose of enabling it, while in its unvulcanized condition, to be handled without
the necessity of employing mandrels, formers, or other similar supports of a
mechanical nature. It is well-known that india rubber, when in its unvulcanized
state, is exceeding elastic, pliable and tacky, and, particularly when in thin sheets
or in tubes, is troublesome to handle. It is also known that the successful working
up of india rubber into tubular or other hollow shapes involves the use of mandrels,
formers, etc. for internal support. The production of an endless tube out of
rubber, where the tube is covered with a fabric in any form, has heretofore involved
the formation of a straight tube or flat strip, the covering of this tube or strip
with the fabric and the bringing together and joining of the ends or ends and
edges both of the tube and the fabric, and subsequent inflation of the partially
completed endless tube against the inclosing fabric for the purpose of permitting
the tube to be finally completed and vulcanized. Where a tube has been made in
the first instance, it has been necessary to build it up on an internal rod or mandrel,
and to remove it from this mandrel before joining the ends. In the making of
hollow articles it has been found impracticable heretofore to produce them complete
where a specific internal form is required, as in the case of foot-balls and the like,
owing to the impossibility of withdrawing the internal former or mandrel.
This invention is directed to an improvement in the art of handling rubber, with
particular reference to enabling the rubber to be manipulated in any desired form
or shape for the purpose of the further covering of the rubber structure with fabric,
etc., which method shall render unnecessary the use of any internal former or
mandrel.
To this end the invention consists in subjecting the rubber in any shape desired,
to an action which shall serve to give to the rubber an inherent, abnormal rigidity,
this rigid or stiffened condition being caused to continue for the period of time
necessary for the further manipulation of the article. The invention further
consists in combining with the rubber the requisite vulcanizing agents, förming it
into the desired shape or form, and then subjecting it to an action which shall
serve to stiffen the rubber and retain it in its stiffened condition a sufficient time for
further manipulation, and then vulcanizing the finished product.
It has been found that one, and as it is considered, the best method of giving to
rubber the desired condition of rigidity, is that of subjecting the rubber to a low
température, preferably below zero Fahrenheit, and in some cases to a temperature

page_text: as low as from 5° to 20° below zero Fahrenheit, when it will, in a reasonably
short time, become sufficiently rigid, that is fairly hard or unyielding and
unpliable, and of greatly impaired elasticity, that it will retain this condition for a
considerable time, depending upon the low degree of the temperature at which it
is treated and the atmospheric temperature to which it is subsequently exposed,
and that when it is allowed to relax, as by thawing, it recovers the attributes of
softness, pliability and elasticity which it possessed before being frozen.
rubber will freeze at a temperature considerably above zero, Fahrenheit, and this
higher temperature may be employed, if desired; but the higher the temperature,
the slower is the rate of freezing, and therefore the lowest available temperature is
preferred.
The
Particular use for the invention here described has been found in the production
of hollow articles which are covered with fabric, such as pneumatic tires for
bicycles, foot-balls and the like. In the manufacture of hollow rubber tires,
particularly the single tube variety, it has heretofore been deemed necessary to
build up the tire, that is to say, to apply the various layers of rubber and fabric
constituting the wall, upon a straight mandrel, then to withdraw the mandrel, and
to bring together and join the ends of the tube and layers of fabric, etc. applied
thereto, and then to vulcanize either under internal air-pressure, or in some other
method by which the intended cross-sectional shape of the tube shall be preserved.
In some cases, instead of forming the tire upon a straight mandrel, and in the form of
a tube, it has been built up on a drum in the form of a flat band, and the edges
brought together and jointed to form a tube. By the method which involves the
utilization of the invention covered by this application, the rubber tube which is to
be covered may be placed in a mold and expanded by internal air-pressure to the
shape of the mold, and then subjected to any desired or appropriate treatment by
which the rubber of the inner tube shall become, for a temporary period, inherently
rigid, as by subjecting it, as described to a sufficiently low temperature for the
necessary period of time. Upon removal from the mold in which it is frozen under
internal air or other fluid pressure, if this be the method practiced, the tube is
found to be stiff, non-pliable and non-elastic, and in this condition it can be covered
with the various forms of fabric and further layers of rubber or other material
which it may be desired to apply to the tube for a covering therefor. The rigidity
of the tube is for all practical purposes the same as if it were placed upon an
internal core or mandrel, and if the freezing temperature be sufficiently low, and.
the temperature of the room in which the further manipulation takes place is not
too high, it will retain its stiff, non-pliable and non-elastic condition sufficiently
long for all further handling. The tube then may be vulcanized in the usual manner
with or without permitting it in the meantime to thaw out.
For the production of foot-balls and the like an entirely similar proceeding is
practised, the rubber in the shape of a ball being preferably frozen under internal
air or other fluid pressure against an external mould, and then removed and
covered with leather or other fabric while in its condition of temporary rigidity and
subsequently vulcanized, if desired.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondent and in what manner the
same is to be performed, I declare that what I claim is :-
1-In the manufacture of hollow rubber articles dispensing with internal supports
by rendering the article self-supporting.
2-In the manufacture of hollow rubber articles dispensing with internal supports
by rendering the article self-supporting, by subjecting it to a lower temperature.
3-The method of preparing india-rubber for further manipulation, which
consists in forming the rubber into hollow shapes, and thereupon giving to the
rubber a condition of temporary inherent abnormal rigidity, substantially as
described.
4-The method of forming covered articles out of rubber, which consists in

page_text: forming the rubber into the desired shape, then giving to it a condition of inherent
abnormal rigidity, and applying a permanent covering to it while in its rigid
condition, substantially as described.
5-The method of forming covered articles out of rubber, which consists in
forming the rubber into the desired shape, freezing it, and applying a permanent
cover to it while in its frozen condition, substantially as described.
6-The method of handling india rubber for the production of hollow articles,
which consists in forming the india rubber into the shape desired in the hollow
article, then giving to the rubber a condition of inherent abnormal rigidity, then
covering the rubber and then vulcanizing it, substantially as described.
7-The method of producing hollow articles out of rubber which consists in
placing raw vulcanizable rubber in a hollow mould, expanding it by internal
pressure against the mould, subjecting the rubber in said mould to a temperature
sufficiently low to stiffen the rubber, removing the rubber in this condition from the
mould, and further treating it as desired, and thereupon vulcanizing it, substantially
as described.
8 The method of producing endless tubular articles out of rubber, which
consists in forming an endless tube of raw vulcanizable rubber, expanding said
tube within a mould, producing in it, while in its expanded condition, a condition of
inherent, abnormal rigidity, withdrawing it from the mould covering it with one or
more layers of fabric or rubber or both, permitting it to relax from its abnormally
rigid condition, and then vulcanizing it, substantially as described.
Dated this 8th day of February 1898.
BOULT & WADE,
Agents for the Applicant.