Improvements in the Manufacture of Compound Pneumatic Tyres for Velocipedes and other Wheeled Carriages.
Year: 1892

page_text: Date of Application, 9th Jan., 1892
Complete Specification Left, 5th Oct., 1892-Accepted, 5th Nov., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Compound Pneumatic Tyres
for Velocipedes and other Wheeled Carriages.
I CHRISTIAN HAMILTON GRAY of Silvertown in the County of Essex,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to that class of pneumatic bicycle tyres in which the air
tube is secured in place, and protected by a detachable elastic envelope, and
consists in providing for such tyres a means of automatically repairing the air tube
when pierced or cut by a stone while in use, as described in the Specification of a
Patent granted to me and bearing date 20th January 1891, No. 1015. In that
Specification I described the air tube as constructed of two kinds of plastic rubber,
the lining or inner coating being made of non-vulcanizable rubber, and the outer
coating of compound rubber that was amenable to the vulcanizing process.
I now propose to make the air tube wholly of pure rubber, or of non-vulcanizable
rubber, which, retaining its tacky character, will, if pierced or cut during wear,
by its elasticity effect the cohesion of the severed parts, and thus restore soundness
to the air tube.
The liability of the tube to be cut will be reduced by the elastic envelope which
in this class of tyre secures the pneumatic tube to the rim, but the additional
provision of automatic recovery from injury will greatly enhance the value of the
covered tyres.
Dated this 0th day of January 1805
NEWTON & SON,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Compound Pneumatic Tyres
for Velocipedes and other Wheeled Carriages.
I, CHRISTIAN HAMILTON GRAY of Silvertown in the County of Essex,
Engineer, 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 that class of pneumatic wheel tyres in which the air
tube is secured in place and protected by a detachable elastic envelope, and
consists in providing for such tyres a means of automatically repairing the air tube
when pierced or cut while in usc.
To this end I make the air tube of pure rubber, or of nonvulcanized rubber,
which, retaining its tacky character, will, if pierced or cut during wear, by its
elasticity effect the cohesion of the severed parts, and thus restore soundness to the
air tube.
The liability of the tube to be cut is minimised by the elastic envelope, which
in this class of tyres is used to secure the pneumatic tube to the rim, but the
additional provision of automatic recovery from injury will greatly enhance the
value of the pneumatic tyre.
In the accompanying drawing, I have shewn in section three forms of compound
tyre made according to my invention.
Fig. 1 shews the rim of a bicycle wheel fitted with an air tube having a
thickened tread, and held in place on the rim by an envelope or cover.
Fig. 2 shews a modification in the sectional form of tread of the air tube, the
other parts of the wheel being the same as in Fig. 1.

page_text: Fig. 3 shews an air tube of equal thickness throughout, held in place on the rim
by an envelope or cover, as in Fig. 1.
In these figures, A is the metal rim of the wheel, in the groove of which the
pneumatic tube B is seated.
This tube is composed of pure rubber, or of nonvulcanised rubber, but it admits
of being pigmented when the pure rubber possesses an excess of tackiness.
By using rubber tubing of this character, it will retain, while uninjured, the
compressed air supplied thereto as well as vulcanised rubber tubes, but with this
additional advantage, viz. that when pierced by a stone or other obstacle in the path
of the rider, the tendency of the tube will be, when pressure on the tube is removed,
for the lips of the cut to close, and form an air-tight joint.
C is the envelope or cover, which laps around the pneumatic tube and rim,
and holds the tube firmly in place, while it forms a suitable protection for
the tube B.
This envelope is conveniently made of canvas coated on opposite sides with
vulcanised rubber compound, and thickened at the tread by the application thereto
of a band or strips of the like material. The whole is then subjected to the
vulcanizing process.
The envelope I attach to the rim by bringing the edges to a butt joint
between the rows of spokes, and securing the edges by herring bone sewing or
otherwise.
To complete the envelope, I may apply a strip of canvas over the abutting edges,
and secure the same in place by cement.
The tube B will be inflated, as usual, through the metal rim, and the process
of inflation may be repeated when air has escaped from the tube, through any
accidental incision made therein.
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 compound pneumatic wheel tyre (composed of an air tube and an envelope
or cover for protecting and holding the tube in place on the rim), the air tube of
which consists of pure or non-vulcanised rubber, and possesses the property, when
pierced, of recovering its air-tight character as above set forth.
Dated this 4th day of October 1892.
NEWTON & SON,
Agents for the Applicant.