Improvement in or relating to Pneumatic Tyres.
Year: 1899

page_text: Date of Application, 26th Aug., 1899-Accepted, 4th Nov., 1899
COMPLETE SPECIFICATION.
Improvement in or relating to Pneumatic Tyres.
I, HENRY BAKER, of 62, Solent Road, West Hampstead, London, N.W.,
Accountant, do hereby declare the nature of my said 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 the inner tubes of pneumatic tyres and to means for
minimizing the inconveniences of punctures in said tubes, and consists in a par-
ticular method of arranging a pair of tubes each of which is fitted with a valve
for inflation purposes.
According to my invention I employ two tubes joined or connected together
side by side but in a particular position to be hereinafter described and in such a
manner that the inflation of either tube causes the pair to roll in the rim so that
the empty tube is always at the side of the tyre and not liable to puncture; the
joint, connection, or attachment being effected during vulcanization or by a suit-
able cement afterwards.
And in order that my said invention may be particularly described and ascer-
tained, reference is hereby made to the accompanying drawings in which similar
letters of reference indicate corresponding parts.
Fig. 1 illustrates the relative positions of the two tubes when united.
Fig. 2 is a section of a tyre (drawn to an enlarged scale) illustrating the action
of the two tubes.
ab are the two tubes which are endless and fitted with valves similarly to
ordinary tubes; as shown in Fig. 1 the tube a is situated somewhat above the
tube 6 which position is important inasmuch as it controls the position of both
tubes when in place in the outer cover c. d is the valve.
On placing the tubes in the rim in the ordinary manner the two valve stems
are inserted through their respective holes in the rim and locked in position by
the usual nuts. Fig. 2 shows the tube b inflated, the tube a being flattened
against the side of the cover c and consequently not liable to accidental punctur-
ing the action of inflating the tube b causes the tube a to lap over its valve, as
shown at a', which helps to rotate or roll the tubes in the rim so that the inflated
tube becomes uppermost, while the empty tube is compressed between the inflated
tube and the cover, and causes the join of the tubes to be always out of harm's
way. The dotted lines in Fig. 2 illustrate the tube a partly inflated and the
tube hanging loosely previous to its being flattened against the side of the
cover.
In order to strengthen the part and to assist the rolling or rotating of the two
tubes in the rim, I sometimes incorporate canvas, or other suitable fabric, or
threads with the rubber, such materials being sometimes carried downwardly in
the vicinity of the valves to afford a stronger connection therewith.
It will thus be seen that on one of the tubes being punctured, it is only
necessary to inflate the other tube to restore the tyre to a rideable condition;
should the second tube be punctured it is necessary to remove the cover and repair

page_text: the punctures in the ordinary manner, the extra tube being merely to enable the
rider to reach a convenient place for repairs.
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
A twin tube for pneumatic tyres, consisting of two tubes joined together in
the position described and shown, with or without the insertion or strengthening
of canvas, fabric, threads, or other material, the tubes being each provided with
an independent valve, the whole arranged to roll in the rim substantially as and
for the purposes set forth.
Dated 26th August 1899.
HENRY BAKER.
By George Downing & Sons,
Chartered Patent Agents, 8, Quality Court, London, W.C.