Improvements in or relating to Pneumatic Tyres and the Air Tubes therefor.
Year: 1898

page_text: Improvements in or relating to Pneumatic Tyres and the Air Tubes
therefor.
JOHN HUBBARD, 6, l'emberton Gardens, Upper Holloway, N., do hereby declare
the nature of this invention to be as follows:-
My invention relates particularly to a means of utilizing a viscous gelatinous
substance, which would be self closing after puncture, so as to save the use of
rubber airtubes in detachable tyres, & of the rubber lining in single tube tyres,
& so to produce tyres that would be both cheaper to make, & would have better
selfhealing properties, than any yet produced. For this purpose I make up a
tube of an absorbent material such as flannel, flannelette, stockinette, plush, or a
loose textured cotton, or other suitable textile material, preferably coated with
a thin layer or proofing of rubber or other non-porous material on the outside,
which may preferably be made to resemble rubber, & put into the tube a suffi-
cient quantity of the viscous fluid to thoroughly satturate the absorbent material,
& thus form with it a film all over the inner surface of the necessary thickness
to make the tube airtight, & capable of self-healing after puncture. In single
tube tyres I line the inside with the absorbent material, which should be made
to adhere to the inner surface of the tyre, & put in the viscous fluid as before.
Dated this the Twenty-second day of April 1898.
COMPLETE SPECIFICATION.
Improvements in or relating to Pneumatic Tyres and the Air Tubes
therefor.
JOHN HUBBARD, 6, Pemberton Gardens, Upper Holloway, North, Tyre Expert,
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 fol-
lowing statement:-
My invention relates particularly to a means of employing a viscous or gela-

page_text: tinous substance which is self-closing after puncture, so as to save the use of the
ordinary rubber air tubes in detachable tyres, and of the rubber ning in
tubular and tubeless tyres, and so to produce air tubes and tyres that are both
cheaper to make and have better self-healing properties than any yet produced.
My invention may also be applied to ordinary rubber air tubes and tyres, to
render them self-healing after puncture, and serviceable when liable to porosity.
In carrying out my invention I employ a viscous substance which has a high
degree of stickyness which may be easily melted for convenience in applying it,
is little affected by ordinary variations of temperature, is not liable to decomposi-
tion or change of character, does not injuriously affect rubber or fabrics and is
cheap. I so apply it that in use it will not flow at all, or will only flow very
slowly. I have found that when the fluid or viscous substance is thoroughly
efficient for its purpose, it can with advantage take the place of the ordinary
rubber air tube, or of the lining in a tyre, as it requires only, in the case of air
tubes, to be enclosed in a pocket, which may be made of a very light and cheap
material while the cost of the viscous body need only be a fraction of that of an
ordinary rubber air tube, and the weight of an air tube thus made may be the
same as, or in any case need only be very little more than that of an ordinary
air tube.
To make air tubes according to my invention I make up a tube of an absorbent
material such as flannel, flannelette, stockinette, plush, or a loosely spun closely
woven cotton, or other suitable textile material, preferably cut obliquely, or as
it is called on the cross, and preferably coated on one side with a thin layer or
proofing of rubber, or other non-porous material, which may preferably be made
to resemble an ordinary rubber air tube. This tube is preferably made by fold-
ing a strip of the material round such a mandril as is commonly used in making
air tubes, while the proofing, which is preferably placed next the mandril, is
unvulcanized; the edges of the strip being overlapped and joined with solution in
the usual way, and then vulcanizing the tube on the mandril. On being taken
off the mandril the tube is turned inside out. I then put into this tube a suffi-
cient quantity of the viscous fluid in a melted condition to thoroughly saturate
the absorbent material, and to form all over its inner surface a film of the neces-
sary thickness to make the tube air tight and capable of self-healing, after
puncture, the fluid being distributed all round the tube by passing it through
suitable rollers or rolling it on a bench with a hand roller.
Air tubes thus made are preferably joined up by bringing the ends together,
solutioning round the joint outside a strip of indiarubber film, and then folding
over the joint, and sticking on with solution in the usual way, a ring of the same
material as that of which the tube is made which must be passed, inside out,
on to one end of the tube before its ends are connected.
If desired existing tyres or ordinary rubber air tubes may be entirely lined or
the tread only lined with absorbent material coated with the viscous fluid.
I find it preferable to fix the valves to the tubes before putting in the viscous
fluid, and to plug or stop up in some convenient manner the interior orifice of the
valve, so that the viscous fluid may not while hot flow into the valve, but that,
when it has cooled and set, the valve may be easily cleared.
To increase the self-healing property of the tube, at the part chiefly liable to
puncture, may form on the interior of its tread portion a pocket rather broader
than the surface of contact with the road into which I put a further quantity of
the viscous fluid, which quantity may be greater in proportion to the area of the
pocket, than the quantity put into the other part of the tube and may be of a
slightly thinner consistency. In use the excess quantity of the fluid will slowly
flow round and round in the pocket, the ends of which should be carefully joined
together, so that it will retain the. free fluid, and thereby all punctures will be
thoroughly closed. This interior pocket is formed on the tube when on the
mandril before vulcanization, by sticking a strip of the same material as that of
which the tube is made along one side of it, the proofed side of the strip, being

page_text: outwards, and its edges being turned in underneath it, and solutioned to the sur-
face of the tube in the usual way.
In tubular and tubeless tyres I line the inside with the absorbent material,
which should be made to adhere to the inner surface of the tyre, and put in the
viscous fluid as before, or apply it when fluid with a brush; and I may provide a
pocket containing some of the viscous fluid in the tread as above described.
Ordinary rubber air tubes and tyres including these which now are useless as
such by reason of their porosity may be rendered efficient and self-healing by
lining the whole or part of their inner surfaces with absorbent material coated as
aforesaid with viscous fluid.
If desired and to prevent adhesion of the inner surfaces of tubes or tubular
tyres made according to my invention, the viscous lining may be covered with
an interior skin of india rubber or gutta percha film, or other suitable material
such as varnish applied in any convenient manner to the viscous film to which
it will readily adhere.
A
Any viscous material possessing the qualities specified above will serve for the
purpose described herein, but the viscous material I have found most suitable
for the purpose is that described and claimed by me in a specification for which
I am now applying for Letters Patent, i.e. No. 4493 of March 1st, 1899. It is
prepared by melting down in any suitable vessel waste vulcanized rubber till it
becomes fluid and remains so when cooled. The rubber being preferably first cut
into shreds or ground up in a mill, no solvent or admixture need be used.
thicker or thinner viscous consistency is obtained by continuing the heating
process for a shorter or longer period which will vary according to the quality
of the rubber used. After melting, the fluid should be strained or filtered to
remove impurities, and in some cases some glycerine, or other suitable substance,
may be added to produce a thinner consistency if desired. This material is very
viscous, boils at a high temperature, and is not appreciably affected by ordinary
changes of temperature, (as I believe unvulcanized rubber so treated is), it does
not decompose or change its character, does not injuriously affect ordinary
rubber or fabric and is very cheap, the material of which it is mainly made being,
as has been said, mere waste, and the process of producing it being extremely
simple.
I find 4 ozs. of the material to be a suitable quantity to put into ordinary air
tubes, and 2 or 3 ozs. a suitable quantity to put into the pockets as herein
described.
I do not limit myself to the precise methods of making tubes and tyres herein
described, or of preparing the viscous substance as they may be variously modi-
fied as occasion may require or suggest, as will be well understood by those
accustomed to the manufacture of these articles; but,
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. Pneumatic tyres or air tubes constructed by impregnating fabrics or linings
of absorbent material with a substance which remains permanently fluid or viscous
at ordinary temperatures, substantially as and for the purposes described.
2. In pneumatic tyres air tubes either separate from the cover, or single iube
or tubeless tyres, lined on the whole or tread portions of their inside surfaces
with an absorbent material impregnated with a fluid or viscous substance of the
character hereinbefore described, substantially as and for the purposes described.
3. In pneumatic tyres air fubes either separate from the cover, or single tube
or tubeless tyres, lined on the whole or tread portions of their inside surfaces with
an absorbent material impregnated with a fluid or viscous substance of the char-
acter herein before described, and provided on their tread portions with a pocket
of the said absorbent material so as to contain an excess of the said fluid or viscous
material, substantially as and for the purposes herein before described.

page_text: 4. In pneumatic tyres air tubes either separate from the cover, or single tube
or tubeless tyres, provided inside the tread portion of the tyre with a pocket of
absorbent material containing a fluid or viscous substance of the character herein-
before described, substantially as and for the purposes described.
Dated this 21st day of February 18OS