Improvements in the Manufacture of Air-cushioned Tyres for Velocipedes and other Wheeled Vehicles.
Year: 1891

page_text: Date of Application, 20th Jan., 1891-Accepted, 21st Feb., 1891
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Air-cushioned Tyres for
Velocipedes and other Wheeled Vehicles.
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 a novel manufacture of tubular elastic tyre for
wheels, in which a cushion of air is imprisoned to maintain the form and
elasticity of the tyre. Tyres of this class have hitherto presented some difficulties
to the manufacturer, it having been usual to find an inlet for the air through
the metal felloe or grooved tyre, and when the air is forced in, to plug this
opening. Tyres of this kind, when once pierced by accident or otherwise, are
liable to collapse or lose their efficiency, and it is then beyond the power of a
rider, during a journey, to restore the efficiency of the tyre.
To provide against the collapse of the tyre, or its loss of hearing power, when,
by accident or otherwise, an opening is made in it, through which the air will
escape, I propose to impart to the hollow tyre an adhesive property, which will
ensure the closing automatically (or by the aid of external pressure) of the opening.
This new property of the elastic tyre provides for its re-inflation by the rider, and
its restoration to efficiency without the aid of an expert.
In carrying out my invention, I provide for the hollow tyre a lining of india
rubber, which lining, when the tyre is submitted to the vulcanizing heat, will not
become vulcanized, but will retain its natural adhesive property, and while offering
no obstruction to a needle-pointed air injector, will close up the pierced opening
when the injector is withdrawn.
Similarly, if the tyre is accidentally cut by a stone in the road, the cut may be
closed up by the natural tendency of the severed surfaces of the uncured rubber
The section of tyre
to adhere, if grit or dirt is removed from the lips of the cut.
which I may adopt will vary according to circumstances, without affecting the
nature of the invention.
In the accompanying drawing, I have shown several varieties of section corre-
sponding externally with those in common use, but it will be obvious that other
varieties may be made to suit the different sections of felloes and channelled iron
employed by manufacturers of velocipedes and other wheeled vehicles.
Fig. 1 represents a tyre of cylindrical section made according to this invention.
a is the external portion of the tyre, made of vulcanized india rubber compound,
and 6 is the lining (that will not harden under the vulcanizing heat), composed,
say, of pure plastic india rubber, or of rubber compound, by which I mean rubber
combined with linseed or hydrocarbon oil and the metallic or earthy ingredients
usually employed in producing compound rubber, but which will retain its viscous
character when exposed to the vulcanizing heat.
Fig. 2 represents a tyre with the tubular lining 6 placed excentrically to the
outer tube, thus giving an increased thickness of tread to the tyre, without increasing
the weight of the material used.
Fig. 3 represents the section of a tyre with the lining tube of an oval shape
externally, its circular bore being excentric to the outer tube a.
Fig. 4 shews a similar section of tyre to that represented in Fig. 1, the part a
including laps of canvas, as employed in the well known manufacture of hose pipes,
for stiffening the tyres.
Figs. 5 and 6 shew sections of lined tyres which may be used when flat
treads are required. The lining tube b. whether composed of pure india rubber.

page_text: or rubber compound having a slight admixture of sulphur, I make either by
'hand from sheet rubber, or by squeezing out the plastic material through a die
in the well known manner. The tube thus constructed constitutes a hollow core
upon which the outer tube a is formed either by hand or by machinery, the core
in the latter case being let through the moulding die. The lined tubing thus
prepared I cut into lengths suitable for forming a tyre, and join up the ends in
the usual way, inserting, previously to joining up, some material which vaporises
at a temperature below the vulcanizing point, in lieu of water, which is commonly
employed for securing the internal pressure requisite for forcing the plastic material
into close contact with the moulding surface during vulcanization.
The vaporizable material which I prefer to employ is either carbonate of
ammonia or carbonate of magnesia, it being undesirable to employ water, as the
presence of moisture within the tyre militates against the adhesion of the pierced or
severed parts of the lining.
The joined-up tubing I place in a metallic mould, and subject to a vulcanizing
heat, which completes the manufacture of the tyre.
Instead of lining the tyre with a tubular core, as shewn in the drawing, it may
suffice to employ, instead of the cylindrical core in the manufacture of the tyre
tubing, a segment of a cylinder or a broad strip of the pure plastic rubber,
placing it in a position to line the more exposed portion of the tyre, and to be
pierced by the insertion of the point of the inflating instrument, when the opening
made by the piercing or cutting instrument will close on its withdrawal, as above
explained. In this case, the manufacture of the tyre tubing will be from sheets
of the prepared rubber.
The inflating instrument which I propose to provide for bicycle riders is shewn
at Fig. 7, and consists of a hollow steel piercer having a lateral opening for the
discharge of air, which is supplied by means of an india rubber injector attached to
the hollow piercer.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that
what I claim is :-
The manufacture of air-cushioned tyres with a lining or partial lining of plastic
rubber, which will resist the action of the vulcanizing heat to which it is exposed,
and provide for the closing up of holes made in the air cell of the tyre, as and
for the purpose above set forth.
Dated this 19th day of January 1891.
NEWTON & SON,
Agents for the Applicant.