Improvements in or relating to Pneumatic Tyres.
Year: 1898

page_text: Date of Application, 22nd Feb., 1898-Accepted, 9th Apr., 1898
Improvements in or relating to Pneumatic Tyres.
A communication from VICTOR CARRIER, of 37, Faubourg de Boeuf Annecy,
(Haute Savoie) in the Republic of France, Engineer.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:
This invention relates to a rubber pneumatic tyre forming two superposed
compartments of special shape. One of the compartments A (Fig. 1) serves to
receive the inner air tube G and the other one B contains ordinary non compressed
air. In this way the bending of the partition C and the deformation of the
other walls caused either by inflating or by the flattening of the tyre during
riding can easily take place and consequently the suppleness and resiliency of
the tyre is preserved.
The portion forming the circumference of the compartment B strengthens the
protective side of the tube containing the compressed air or inner tube G. The
shape of the upper compartment is semi-circular or arched with straight portions
at the sides and connected by a horizontal line; this is the shape of the section
that the tyres assume when not inflated. (Fig. 1).
Fig. 2 shows the section when inflated and when there is no load on the wheel.
Owing to the flexibility of the portions forming the lower compartment B and
chiefly of the part forming the partition between the two compartments whereby
it can bend towards the lower cavity B the compartment A will tend to assume
circular shape and will come nearer to said cavity. The dotted circle D, is a
perfect circle, the area of which corresponds to the original section. In other
words the original corners E (Fig. 1) of the compartment A will come nearer
the circumference of the circle as well as the horizontal line separating the two
compartments A and B.
To enable the different portions of the pneumatic tyre to alter their shape more
freely it is necessary that the cross section of the compartment B should be capable
of becoming smaller without the atmospheric pressure in it being increased by
compression. For this purpose several holes F are made in the partition between
the two to enable the air from B to escape between the canvas and the walls of
the partition C.
Under the influence of a load the tyre will assume the shape shown in Fig. 3
that is to say a new shape. This continual transformation of the section can take
place only owing to the special shape of the walls which retain their suppleness
in spite of having a considerable thickness.
The canvas or fabric portions H and K serve to limit the deformation of the
shape of the tyre and to strengthen the corners E of the tyre, but it is necessary
The fabric H is inserted
for this purpose to arrange them in a special manner.
or embedded into the body of the tyre and is very nearly parallel to its outline.
The tyre is provided with two wings or edges L and M forming the sides of the

page_text: compartment A for the compressed air the fabric H issuing from the thickened
lower portion of the tyre in which is situated the compartment B and forming the
inner surface of the edges L and M. It projects beyond the latter to a certain
extent by means of which it can be connected to the fabric K. This latter follows
the inner portion of the thickened part of the tyre and joins the fabric H secured
to the wings L and M. Like the fabric H the fabric K also projects beyond the
upper edges of the wings. The projecting portions of the two fabrics serve to
connect them together and to maintain the tyre in the rim by means of wires O
round which they are rolled up as shown on a large scale in Figure 4.
Having now particularly described and ascertained the nature of this inven-
tion as communicated to me by my foreign correspondent and in what manner
the same is to be performed, I declare that what I claim is:-
1. A pneumatic tyre for wheels comprising a tread portion having a central
passage B having a substantially horizontal top and curved base and side portions
forming with the rim an arched compartment for air under pressure the two
compartments being separated by a horizontal flexible partition adapted to bend
when the tyre is inflated and enable the portions forming walls to bend freely
and come into an approximately circular form substantially as described.
2. In a pneumatic tyre of the character described the insertion of two pieces
of fabric one in the body of the tyre passing below the lower compartment and
extending up the sides of the tyre and the other passing above the lower compart-
ment and lying within the separating partition and also extending up the sides
of the tyre substantially as and for the purpose described.
3. In a pneumatic tyre of the character described the use of apertures enabling
the air to escape from the lower to the upper compartment when the pressure
increases owing to the decrease of the section caused either by the bending of the
separating partition or the deformation of the walls of the tyre during riding
substantially as described.
4. The combination and arrangement of parts constituting the complete pneu-
matic tyre, substantially as described and illustrated in the accompanying
drawings.
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