Improvements in Pneumatic Tyres.
Year: 1896

page_text: Date of Application, 5th May, 1890
Complete Specification Left, 5th Feb., 1897-Accepted, 27th Mar., 1897
Date
on,
May, 890
Complete Specification Left, 5th Feb., 1897-Accepted, 27th Mar., 1897
Improvements in Pneumatic Tyres.
I, HIRAM STEVENS MAXIM, of 18 Queen's Gate Place, in the County of Middlesex,
Mechanical Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to improvements in pneumatic tyres which are especially
intended for use with the wheels of horseless carriages, velocipedes and other road
vehicles.
In
The majority of pneumatic tyres as at present constructed consist of an inner.
air-tube and an external cover generally formed of india rubber and canvas.
order to hold the external cover in place the latter has been provided with an endless
wire at each of its edges. These wires have to be made so that they form circles of
nearly the same diameter as that of the rim of the wheel to which the tyre is to be
applied; very little difference therefore exists between the two diameters and when
the wheels are not made with any degree of accuracy, that is to say when their
diameter varies considerably, much difficulty is occasionally experienced in attaching
and detaching the tyres. When an india-rubber tube closed at its ends is inflated
with air, it may expand either in a longitudinal or in a transverse direction, becoming
either larger or longer or both and if such tube be not free to expand in one of these
directions it will then expand in the other.
In accordance with my present invention I employ an ordinary internal air-tube but
dispense altogether with the endless wires or any other means of maintaining a
rigid diameter to the edges of the outer cover, the object of my invention being to
make a tyre that will fit varying sizes of wheels. I prefer to embed within the
material comprising the outer cover and at a point in proximity to the tread thereof
a number of convolutions of very strong linen or other suitable cord which is
preferably in one continuous piece. This cord requires no joints or splices and not
only prevents puncture but at the same time prevents any stretching of the tyre in
a peripheral direction which stretching is apt to result when the fibres or threads
are in a diagonal position or are interwoven as warp and weft threads.
The internal edges of the outer cover may be inade hollow and in order to retain
their shape and at the same time permit of their diameter being reduced in a
circumferential direction relatively to the wheel I place in each groove a very light
spiral spring preferably of steel wires or ribbon.
With such a tyre it is not necessary for the rim of the wheel to be dovetailed or
provided with any hooked portions, it may be provided with flanged faces or may be
of the form employed with solid tyres. Upon placing the cover on the rim and
inflating the tube the latter becomes distended and the internal diameter relatively to
the wheel, becomes smaller and the inner edges of the cover become shorter, the
spiral springs allowing the said edges to be compressed when they are brought
downward firmly to the face of the wheel and on the flanges; the circumferential
expansion of the tyre is prevented by the aforementioned cords.
By another system employed to suit different shaped rims I employ a series of
stiffening pieces in the internal edge of the outer cover which pieces may be formed
either in short or long lengths, the cover being secured to the said pieces at a point
near their external ends. These pieces are arranged in such a manner that when
the air-tube is inflated it holds the inner ends or sides of the said pieces downward
thus causing the external ends or sides of the pieces to engage with the rim of the
wheel and retain the tyre firmly in place, the said rim being suitably formed to

page_text: enable the pieces to effectually engage therewith. These stiffening pieces may be
said to act as levers whose fulera are at the edges of the outer cover.
By reason of these pieces not being continuous the internal diameter of the tyre
can be reduced to fit any wheel.
Dated this 5th day of May 1896.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, W.C., Agents for the Applicant.
Improvements in Pneumatic Tyres.
I, HIRAM STEVENS MAXIM, of 18 Queen's Gate Place, in the County of Middlesex,
Mechanical 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 pneumatic tyres which are especially intended for use
with the wheels of horseless carriages, velocipedes and other road vehicles.
The majority of pneumatic tyres as at present constructed consist of an.inner
air-tube and an external cover generally formed of india rubber and canvas.
In
order to hold the external cover in place the latter has usually been provided with
an endless wire at each of its edges, and it is necessary to so arrange these wires that
they form circles of nearly the same diameter as that of the rim of the wheel to
which the tyre is to be applied. Therefore if the wheels be not made with accuracy,
that is to say, if they be not truly circular, difficulty is occasionally experienced in
attaching and detaching the tyres; or if the diameters of the wheels for which
the tyres are intended vary relatively to one another, the tyres are not easily
interchangeable.
It is known that when an india-rubber tube, closed at its ends, is inflated with air,
it can expand either in a longitudinal or in a transverse direction and becomes either
of increased diameter, or of increased length, or both, and if such tube be not free
to expand in one of these directions it will expand in the other.
In accordance with my invention I employ an ordinary internal air-tube but
dispense altogether with the inextensible endless wires or any other means of
maintaining a rigid,
or unvariable diameter at the edges of the outer cover; one of
the objects of my invention being to make a tyre that will fit wheels of slightly
varying diameter. I prefer to embed within the material comprising the outer cover,
at the tread thereof, a number of convolutions of very strong cord preferably in
one continuous length. This cord requires no joints or splices and not only renders
the tyre less liable to puncture but at the same time prevents any stretching of the
tyre on its outer periphery as would be likely to result if the fibres or threads were in
a diagonal position or were interwoven as warp and weft threads.
The edges of the said cover may be made hollow, and in order to retain their
shape and at the same time permit the inner circumferential diameter of the tyre,
where it lies against the wheel rim, to be reduced I place in each groove a light
spiral spring preferably of steel wire or ribbon capable of compression.
By a modification of my invention I employ a series of stiffening pieces of any
convenient length in the edges of the outer cover, the cover being secured to the
said pieces at a point near their external edge. These pieces are arranged in such
a manner that when the air-tube is inflated it presses the inner edges of the said
pieces downward thus causing their external edges to bear against or engage with
the rim of the wheel and retain the tyre firmly in place, the said rim being suitably
formed to enable the pieces to effectually engage therewith. These stiffening pieces
may be said to act as levers having their fulcrums near the edges of the outer cover.
By reason of these pieces not being continuous, the internal circumference of the

page_text: tyre can be reduced to fit wheels of smaller diameter than that of the wheels for
which the tyre was originally intended.
In order that my said invention may be clearly understood and readily carried
into effect I will proceed to describe the same more fully with reference to the
accompanying drawings, in which
Figure 1 is a transverse section of one form of my improved tyre applied to a
wheel-rim, and
Figure 2 is a side elevation of the same.
Figure 3 is a transverse section, shewing another form of my improved tyre
applied to a wheel-rim of a different cross-section.
Figure 4 is a transverse section showing a modified form of the tyre illustrated
in Figure 3, and
Figure 5 is a horizontal section on the line 1. 1. of Figure 4.
Figures 6 and 7 are fragmentary sectional views shewing slight modifications of
the tyre illustrated in Figures 4 and 5.
Figure 8 is a transverse section of another form of my tyre applied to a
wheel-rim, and
Figure 9 is a plan of the underside of this tyre removed from its wheel-rim.
Like letters of reference indicate similar parts in all the figures.
A is the outer cover of the tyre composed of vulcanized indiarubber, and B is
the canvas with which said cover is provided as usual. C, C are the thickened edges
of the outer cover. D is the air tube, and E is the wheel-rim. F is the tube to
which the inflating valve is connected.
Gis the continuous winding of strong cord or similar material which is embedded
in the rubber of the cover A at its outer periphery or tread portion, and serves, as
before stated, to prevent the outer circumference of the said tyre from increasing
in diameter when the air tube is inflated. H is a flap with which one edge of the
said outer cover is provided, the said flap consisting in Figures 1, 2 and 3 of an
extended portion of the canvas B embedded in rubber. The said flap may consist of
either one continuous piece or of comparatively short sections as shown in
Figure 5.
II are the light spiral springs with which the bollow edges of the outer cover
are provided, these springs serving the double purpose of strengthening the edges C
and of permitting the inner circumference of the tyre where it lies within the
wheel-rim, to contract and grip the said rim when the air tube is inflated. This
contraction takes place, as already stated, by reason of the convolutions of cord G
resisting the expansion of the air-tube at the outer circumference of the tyre, and as
a consequence the air tube tends to expand or bulge inwardly towards the wheel-rim,
thereby decreasing the inner circumference of the tyre and causing it to press upon
and hold the inner edges of the outer cover tightly against and within the wheel-rim.
If desired cork cores may be employed within the hollow edges C of the outer cover
in place of the springs, or I may employ any other suitable substance that will
permit of contraction in the circumference of the tyre at the said edges, when the air
tube is inflated.
By these means it is not necessary for the wheel rim to be dovetailed or provided
with any hooked portions for the edges of the outer cover to engage with, the said
rim being formed with plain upright or plain divergent flanged edges as indicated in
Figures 1 to 7 of the drawings.
When the wheel-rim has upright flanges the inner edges C of the outer cover lie
upon the flat bottom of the said rim, and if desired a packing piece J composed of
felt or other suitable material may then be interposed between the said edges Cas
shewn in Figure 3 and would serve as a bed for the flap H to lie upon.
Instead of forming the said. edges of circular shape in cross-section they
may be formed rectangular, as shewn in Figures 6 and 7 and would then serve as
bearing surfaces or shoulders c for the flap to rest upon, and permit the edges of
the outer cover to be very effectually held in place within the wheel rim.
In Figures 4 to 7 I have shewn the flaps H furnished with internal strips of thin

page_text: metal, wood or other hard and light materiál in place of canvas as in Figures 1 to 3;
and in Figure 7 the said internal strips are made of curved form so that the pressure
of the inflated air tube will tend to straighten them and thus cause them to exert an
outward pressure upon the edges of the cover in a direction towards the upright
flanges of the wheel-rim, as well as a downward pressure towards the Bat bottom of
the rim. When the said flaps are formed with hard internal parts as just above
described, I prefer to leave a short space between contiguous sections of the flap as
shown in Figure 5, so that the aforesaid contraction of the inner circumference of
the tyre will not be interfered with.
In the construction of tyre illustrated by Figures 8 and 9, the edges of the outer
cover have series of strips or pieces a a which are so arranged that the width of
their inwardly projecting portions a a is much greater than the width of their
outwardly projecting portions, (see Figure 9) and the flanges of the wheel rim are
in this construction advantageously formed with slightly inward-bent edges as
shewn in Figure 8. When the air tube is inflated its expansion towards the wheel-
rin causes the said strips a to turn downwardly in the manner of levers, as indicated
by the dotted lines in this figure, and by reason of the outer or shorter parts of said
strips abutting firmly against the flanges of the wheel-rim the tyre is held securely in
place. I prefer to so arrange the said strips that spaces exist between them and that
those on one edge of the outer cover break joint with those on the opposite edge as
shown in Figure 9.
I am aware that tyres have before been made with internal flaps for preventing the
leakage of the air with which they are inflated, but the flaps H herein described do
not serve this purpose, nor do I wish to claim them therefor. I am also aware that
the edges of the outer covers of tyres have been provided with wires for retaining the
tyres upon the wheel-rims, but I do not berein claim the use of wires for such
purpose, on the contrary my object is not to provide the covers with inextensible or
rigid wires but with contractile devices for the purpose I have hereinbefore stated.
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. A pneumatic tyre whose outer circumference at the tread-portion is inextensible
while its inner circumference near the wheel-rim is made contractile or resilient
substantially as described and for the purpose specified.
2. A pneumatic tyre provided with convolutions of strong cord or thread or other
suitable material embedded in the outer portion or tread of the cover substantially as
described and for the purpose specified.
3. A pneumatic tyre having the edges of the outer cover provided with spiral
springs or similar contractile or resilient devices substantially as described and for
the purpose specified.
4. The combination with the outer cover having inextensible material embedded in
its outer circumference, of a series of flaps provided with strips of metal or other
suitable material of flat or curved form, substantially as described and for the purposes
specified.
5. A pneumatic tyre having on each edge of the outer cover a series of strips
which, under the action of the pressure due to the inflated air tube, act in a lever-
like manner to retain the tyre to the wheel-rim substantially as described.
6. A pneumatic tyre made in accordance with one or other of the examples
illustrated in the accompanying drawings for the purposes specified.
Dated this 5th day of February 1897.
HASELTINE, LAKE, & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.