Improvements in Pneumatic Tyres.
Year: 1898

page_text: Improvements in Pneumatic Tyres.
I, ELEAZER KEMPSHALL, of Newton, in the County of Middlesex and State of
Massachusetts, United States of America, Gentleman, 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 pneumatic tyres of the kind that have a tread-surface
provided with a cushion of sponge-rubber or other suitable material to protect the
air-chamber from puncture and to increase the resiliency of the tyre.
My invention has for its object to provide an additional safeguard against punc-
ture in case the puncturing projection or object succeeds in penetrating the pro-
tecting cushion.
According to my invention I employ a strip of non-extensible air-proof or other
suitable material interposed between the cushion and air-chamber, and adapted
to prevent the compression of the cells of the cushion by the pressure of air in the
tube. The said strip is such that air cannot pass through or along it, and hence
if it should be perforated, air from the air chamber will not be able to escape by
penetrating such strip and reaching a point at the side or other weak part of the
tyre where it may escape through the outer covering.
In order that my said invention may be clearly understood and readily carried
into effect I will now proceed to describe the same more fully with reference to
the accompanying drawings, in which :-
Figure is a cross-section of a pneumatic tyre embodying my invention.
Figures 2 and 3 are similar views showing the tyre at different stages of its
formation.
The same letters of reference indicate the same parts in all the figures.
a is the air-chamber, which is composed of rubber and is made by forming an
unvulcanized rubber tube upon a rod or mandrel. Before the tube is vulcanized
I apply to its outer portion a strip b of any material which is impervious to air,
or in other words, which, in the event of a puncture through the said strip and
the air-tube a, will not permit the air escaping from the tube to work its way
along the width of said strip. It is a fact that the strip b, if made of certain
materials ordinarily employed in the manufacture of pneumatic tyres-for

page_text: instance. ordinary textile fabrics with or without a coating of rubber-would
permit air escaping through a puncture in the air-tube a and in the said strip, to
penetrate along the strip and work its way along the side of the tyre until it
found a means of escape.
By using a strip b of some material which will not permit air to pass through
or along it in any direction, I prevent loss of air from a punctured air-chamber
when a cushion c of sponge-rubber is placed upon the outer side of the strip h.
To this end the strin b may be made of any suitable non-extensible material, such
as manilla paper, glazed muslin or the like. After the strip b has been placed
upon the air-tube. as shown in Figure 2, the sponge-rubber cushion c, which has
already been partially vulcanized and rendered spongy, is placed upon the outer
surface of the strip b, as shown in Figure 3, and the whole is then enclosed in a
suitable jacket or wrapper composed of one or more layers of fabric. such as
is ordinarily used in the manufacture of pneumatic tyres. I have here shown two
lavers, an inner layer d and an outer laver . the inner laver bearing upon the
air-tube a and upon the outer surface of the cushion c. Upon the outer laver T
form an external coating e of unvulcanized rubber. The tyre is then subjected
to vulcanization and completed in the usual manner.
In the completed tyre the air-tube adheres closely to the air-proof strip b, and
is thereby rendered non-extensible toward the sponge-rubber. and in the event of
the cushion and the strin b being penetrated by any puncturing projection or
object so that the air-tube is punctured, the air that escapes through the perforation
in such strip cannot work its way through the unperforated material of the strip b
and toward the edges of the latter, owing to the nature of the strip. Thus such
which
cushion c,
air can only pass through the perforation into the
Owing to the
remains in its normal uncompressed yielding condition.
cellular nature of this cushion the perforation made in it is closed
by the expansion of the walls of the cells of the cushion, so that there is no
objectionable escape of air from the tube through the cushion: and, owing to the
non-extensible strip b. the said cellular nature of the sponge-rubber cushion is not
materially altered either by the pressure of air confined in the tube a or by the
slight amount of air that may escape through a puncture into a few of the cells.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. In a pneumatic tyre of the kind referred to, a strip of non-extensible material
interposed between the cushion and air-chamber for the purposes specified.
2. In a pneumatic tyre of the kind referred to, the combination of the
parts b, and, substantially as described with reference to the accompanying
drawings.
T: 01 dor of November 1808
HASELTINE, LAKE & Co..
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.