Improvements in the Construction of Covers for Rubber Tyres and in Rubber Tubing.
Year: 1894

page_text: Date of Application, 30th June, 1894-Accepted, 1st Sept., 1894
COMPLETE SPECIFICATION.
Improvements in the Construction of Covers for Rubber Tyres and
in Rubber Tubing.
I, JOHN EBENEZER HOPKINSON of Para Rubber Mills, West Drayton, in the
County of Middlesex, Manufacturer of India Rubber, 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 :—
My invention relates to improvements in the construction of covers for rubber
tyres and in rubber tubing whereby the same are rendered practically puncture
proof, and also in the use for, and application to such purpose of a certain novel
elastic material which I propose to call "vulcanine."
The object of my invention is to produce in an economical manner a homo-
geneous flexible tube or cover of a puncture proof nature and of greater durability
than those of existing forms and methods of construction.
In constructing covers for tyres according to my invention I take two or more
strips of rubber of different widths which are superposed in such a manner that the
narrowest strip is lowermost, and upon this lower strip I place one or more layers
of a material which I designate as "vulcanine" consisting of a mixture of para
rubber, asbestos, litharge lime and powdered zinc, to which is added a greater
percentage of sulphur than is contained in the rubber strips the whole being com-
pounded whilst the rubber is in a plastic condition, whereby during the process
of vulcanizing the layers of material thus added become thoroughly incorporated
with the strips of rubber but acquire a much harder consistency.
In order that my invention may be clearly understood reference is had to the
accompanying drawings upon which
Figure 1 is a section of the rubber strips with a layer of my puncture proof
material shewing the method of construction of my improved cover.
Figure 2 represents the same after it has been compressed in the mould.
Figure 24 illustrates the same curled in form suitable for covering the inner
tube of a tyre.
Figure 3 is a section of a tube or hosepipe with the strengthening material
applied inside, and
Figure 4 is a similar section shewing the strengthening material applied exteriorly
to the tube.
In constructing my improved cover I take two or more strips of rubber of
graduating widths, the widest A, corresponding to the external dimensions of the
cover, and place them in the position shewn on Figure 1 which represents two layers
of rubber and one of strengthening material.
The strips thus arranged are then submitted to heat and pressure in a mould in
the ordinary manner where they assume the form shewn in section on Figure 2.
As will readily be seen thereon, the outer surface of the strip A presents an integral
seamless surface exteriorly and completely encloses the inner layers and strength-
ening portion C whereby their joining edges are protected against friction or injury,
and in the case of a covering for tyres, against the effects of dampness and
adhesion of mud and grit.
I may also use sheet vulcanine prepared as above stated for the interior or
exterior portion or casing of a tube or for other similar purposes as shewn on
Figures 3 and 4.
The covers thus formed may be made in straight lengths, and joined at their ends
in the usual manner, or the cover may be moulded in one continuous circle.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In the manufacture of strip rubber for tyre covers or tubes, the combination
with the same of one or more layers of "vulcanine" having in its composition a
super-addition of sulphur whereby in the vulcanizing process the same is endowed
with a greater degree of hardness, as and for the purposes specified.
2. Rubber tubing coated interiorly or exteriorly with vulcanine, as and for
the purposes described.
Dated this Thirtieth day of June 1801