Improvements in or relating to Pneumatio Wheel Tyres.
Year: 1892

page_text: Date of Application, 7th June, 1892-Accepted, 1st Oct., 1892
COMPLETE SPECIFICATION.
Improvements in or relating to Pneumatio Wheel Tyres.
I, JOHN FULLERTON PALMER, of Riverside, County of Cook, State of Illinois,
United States of America, Gentleman, 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 :-
My invention relates to the production of a pneumatic tire of the kind which is
capable of closing automatically any punctures which may be formed therein.
The purpose of my invention is to provide in the tire, composed mainly of
rubber and containing air under pressure, a tread portion of increased thickness
and held under so called compression, contraction or tension, whereby any
punctures that may occur in the tread portion, as by a pin point, knife blade,
sharp stone or the like, shall be automatically closed and the exhaust of air
through said punctures shall be prevented. Incidentally, the character thus
given to the tire permits the same to be inflated without the employment of the
air-filling tube common with previous structures of pneumatic tires, the operation
being effected by introducing a sharp pointed nozzle connected with the air-
pump.
or like
Generally speaking, the compression or tension of the thickened tread portion
of the tire is accomplished by reversing its curvature transversely from a concave
to the intended convex or nearly convex condition, the outer surface being, during
this change of curvature, held in close adhesion to a strip of canvas
substantially non-stretching fabric. It will be observed that in this manner the
compression of the rubber, so called, is not brought about primarily by the
exercise of internal pneumatic pressure, and this is considered an important
feature of the invention.
In carrying out the invention for the production of a pneumatic tire the same
may be done in either of two ways: That is to say the inner tube may be made
in a primarily open form with the lateral edges in the form of flaps, which are to
be sealed together on the hub side of the tire to produce the tube; or the strip of
rubber having the flaps, as described, may have on a central part a flap of pliable
and usually somewhat thin rubber, which forms a closed air-tube, the flaps being
beaded or ribbed at their edges to enter a slot in the felly. Both these forms are
illustrated on Sheets 12 and 3, respectively, of the accompanying drawing and
will be described in detail. The principle involved in both is the same.
In the drawings, Sheets 1 and 2:
Figure 1 is a transverse sectional view illustrating the method of molding the
rubber upon the canvas before reversing the curvature to produce a compression of
the tread portion:
Figure 2 is a view illustrating the position of the tube in the act of reversing
the curvature ;
Figure 3, a view showing the tube reversed before sealing; and
Figure 4, a sectional view of a tire made in this manner after the same has
been formed into a tube.
Sheet 3 :
Figure 1 is a cross sectional view in the nature of a diagram showing, by dotted
lines, the integral inner tube and retaining envelope portions molded to describe a

page_text: curve in one direction and prior to having their curve reversed to form the tire, as
shown in the full line representation and which is applied to a hollow slotted wheel
felly by my improved fastening means;
Figure 2 is a broken cross sectional view, diagrammatic in its nature, of the
hollow slotted felly, to which the tire fastening means are undergoing application ;
and
Figure 3 is a view like that presented in Figure 2, but showing the tire fastening
means completely adjusted in place.
Referring first to the structure shown in Sheets 1 and 2, A represents the rubber
portion of an inner tube for a pneumatic tire, and B the canvas strip therefor, the
office of which is particularly to serve as an inelastic backing for the tread portion
through the medium of which, on reversal of curvature, the requisite compression
or contraction is effected. As will be observed upon an examination of Figures 1
and 2 Sheet 1, the rubber portion A comprises a section a which is thickened and
two lateral flaps a² which are not thickened, and have their edges by preference cut
out for the purpose of joining them together.
By preference also the canvas backing is extended laterally into flaps b, the
edges of which may be sewed together in completing the tube. It should be
understood, however, that the flaps of canvas b may be entirely omitted without
departing from my invention, or in any sense affecting its operativeness, their
employment being purely arbitrary.
To produce the tire I proceed as follows: Upon a ring shaped mandrel,
properly curved in cross section, the strip of canvas is firmly stretched, and in
order to bring about a conformity with the curvature of the mandrel, the canvas
may comprise two strips opposite in their character, each cut on the diagonal with
longitudinally diagonal fibres and transversely diagonal short fibers; although it
should be understood that any other mode of giving to the canvas a non-stretching
character coupled with a suitable curvature to conform to the mandrel, may be
employed in its place without departing from my invention. In this connection it
may be further stated that canvas is not the only material which I intend to
employ, any suitable flexible material having the essentially requisite character-
istics being capable of use without departing from my invention. The canvas
having been applied to the mandrel with or without the flaps b, the rubber portion
of the inner tube is thereupon molded upon the mandrel, carrying the canvas as
described. The tread portion of the rubber is thickened, and it is found in some
cases convenient to mold the thickened portion and the flap portion separately,
that is to say, first to mold the rubber with the thickness of the flap portion and
in a continuous strip from edge to edge, and afterward to mold on the tread
portion a further strip of the width intended to give to the tread portion an
increased thickness. It is to be understood that it is usually found desirable to
mold the rubber before vulcanization, supplying it with the requisite vulcanizing
ingredients, and after it has been molded upon the mandrel in the manner
described, it is subjected to the proper heat, &c. for producing vulcanization.. One
effect of vulcanization is to produce an intimate cohesion between the canvas
backing and the tread portion of the tire on the under face thereof, or that
adjacent to the mandrel.
After vulcanization the canvas and the rubber secured thereto are withdrawn
from the mandrel and the curvature reversed in the manner illustrated in
Figures 1, 2 and 3,. Sheets 1 and 2 so that whereas the canvas,. when on the
mandrel was between the rubber and the center of the ring, it has become changed
to a position where the rubber shall be between the canvas and the center of the
ring, the canvas, in this operation, being changed from a concave to a convex form
in cross section, and the thickened or tread portion of the tube being caused to
have a reverse curvature to correspond. It is not deemed absolutely requisite that
a. perfect curve in cross section shall be produced, as it is found that a change
from a concave to a very slightly convex or approximately flat condition produces
a desirable result in the finished product. It is merely essential that such a

page_text: change in the curvature of the canvas in cross section, and hence the curvature of
the thickened rubber shall be effected as will bring about a substantial compression
or contraction of the thickened rubber.
The curvature being effected as described, the free ends of the flaps t of rubber
are joined together by a suitable cement, the strength of the joint being materially
increased by the outer envelope of canvas generally employed with tires of this
nature.
Referring to the structure shown in Sheet 3; the air tube proper is formed of a
rubber web A molded, along its edges, on a rubber strip B sufficiently wide to
produce, when formed into a tube, a tire of desired diameter and which should be
about double the width of the web A, the latter being concentric therewith. The
outer surface of the strip B is backed with inelastic material, preferably canvas r,
which may be secured to it by vulcanization.
The foregoing describes my invention as involving the essential construction,
preliminary to forming thereof an inner inflatable tube, afforded by the web A
and opposing portion of the rubber strip B, and a retaining-envelope afforded by
the whole of the canvas-backed strip B, turned about the web to envelop it and
have its edges fastened together in any suitable manner, by lacing, for example.
A tube so constructed will, in a measure, even if the rubber B be of uniform
thickness throughout, be self sealing though the rubber B be a straight strip bent
into tubular form and joined together at its ends into the shape of a tire; since
the mere bending of the rubber will compress and densify it somewhat and enable
slight punctures to close themselves by the expansion into them of the surrounding
compressed rubber. When the tube has been so formed, the web A will occupy
the relative position indicated by dotted lines inside the full-line representation in
Figure 1 Sheet 3; and by then forcing air under pressure into the space confined
by the web A, which then is in the nature of a diaphragm, the web will be
stretched into the shape of a semi-cylinder and form the base or inner half of the
air-tube proper, as it is shown by the full line in Figure 1.
It should be here stated that a pneumatic tire when formed with the details of
construction as described, or in accordance with the preferred construction herein-
after described, may have the web A and canvas-covered strip B originally either
in a straight length, as stated, adapted to be bent into tubular form, or in an
endless, or annular, length, for which it may be bent.
It is preferred to mold the web A and canvas-covered strip B in the same
manner indicated for the strip alone in Sheet 1, and to make the rubber B at least
double the thickness of the web A, along its longitudinal central portion, whence it
tapers toward both edges, preferably to about the same thickness as the web. By
this means, when the parts A and B are turned to describe the opposite curve, the
rubber of the envelope B will, (particularly if thickened in the manner described
where, as will be seen, it eventually forms the tread,) be materially compressed
inside the canvas or other inelastic fabric r, and thus be self-sealing, in the sense
hereinbefore suggested, to a high degree, sufficient, in fact, to close punctures of
considerable proportions.
As the outermost covering of the tire should be rubber on the outer surface
thereof, I inclose the tube formed with the web A and canvas-covered rubber B,
in a covering of rubber C, which may, but not necessarily, be lined with an
inelastic fabric q, such as canvas; and fasten the covering C in place in any
suitable manner, but preferably by the fastening means hereinafter described.
The fastening means which I prefer to employ with this tire comprise beads
along the edges of the canvas-covered retaining envelope B adapted to be inserted
and confined in a slot in the felly or rim of the wheel. As shown the beads E are
in the form of wedges formed by folding the rubber and canvas strip inward along
its edges and vulcanizing them to harden and consolidate them; and they are
especially adapted to co-operate with a slotted felly D of the hollow construction
illustrated, though they are also capable of similar use with a circumferentially
slotted felly forming a mere rim. In either case the fastening operation also

page_text: produces the formation of the cylindrical tire, since first one bead is inserted into
the slot of the felly D and then the other, the insertion being attended by the
reversal of the curve in which the dotted representation in Figure 1 presents the
parts, to that shown by the full lines to be described by them.
It is found desirable to thicken the rubber B toward its opposite edges, as
indicated at r, since thereby they the more compactly fill the slot p. When the
edge-portions are so thickened, however, they render it necessary to proceed, as
indicated in Figure 2, to insert them, by introducing the bead E first inserted into
the slot far enough to bring the thinner portion of the retaining-envelope B to the
edge of the slot in order that the other bead E may be slipped past it into the slot.
Then the tire is righted on the felly, thereby bringing both beads coincident
against the under sides of the edge-portions of the slot, which stop them against
withdrawal.
The cover C is then applied and fastened in any suitable manner, as by
cementing it, or, and preferably, by clamping it along its edges between the felly Ď
and retaining-envelope B.
The subsequent inflation of the rubber web A, whereby it is pressed against the
fastening edges of the retaining envelope B, obviously tends the more securely to
retain the beads E against, withdrawal from the slot p, and furthermore, effects
firm clamping of the edges of the outer covering C.
For the purpose of inflating the tire the point of a syringe pump may be inserted
through the tread portion and air thus forced in. When the point is withdrawn,
the normal tendency given to the rubber by the compression effected under the
influence of the curvature of the canvas serves automatically to close the puncture
and prevent the air from exhausting. Any small aperture that may occur in the
tire at the tread portion is automatically closed for the same reason.
It is to be noted that the characteristic quality thus given to the tread portion
is present regardless of the fact whether air under compression is introduced into
the tube or not. In referring to air as the tube inflating medium, it is to be
understood that I intend to cover steam, gas, water or any fluid that may be
available as a substitute for air, and the term "rubber" is intended to cover the
genus of which rubber is the best known example.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that I am aware
that it has been previously proposed to make pneumatic tyres of india rubber in a
state of compression for the purpose of closing punctures but what I claim is,―
3-The method of producing an inner tube for pneumatic tires, which consists
first in applying to an annular mandrel having the proper curvature, a curved non-
stretching annular strip of flexible material, molding upon said mandrel a strip of
rubber having its edges unjoined, thickening the rubber on the outer side of the
mandrel or form, vulcanizing the parts together, and thereupon reversing the
curvature of the flexible material and thickened portion of the rubber and joining
and sealing the edges of the strip to form the air tube, substantially as described.
The method of integrally forming the inner air-tube and canvas-covered
retaining envelope therefor of a pneumatic tire, which consists in molding a
web A of rubber with a canvas-covered rubber strip B and forming them into the
shape of a tire, substantially as described.
5 The method of integrally forming the inner air-tube and self-sealing canvas-
covered retaining-envelope therefor of a pneumatic tire, which consists in molding
a web A of rubber with a canvas-covered rubber strip B on a curve, and then
reversing the curve and forming the integral air-tube and retaining-envelope into
an endless tubular tire-shaped ring, substantially as described.
6-The method of integrally forming the inner air-tube and self-sealing canvas-
covered retaining-envelope therefor of a pneumatic tire, which consists in molding
on a curve a canvas-covered rubber strip with a thickening of the rubber toward
its longitudinal center and with a web A of rubber along its thickened portion,

page_text: and then reversing the curve and forming the integral air-tube and retaining-
envelope into an endless tubular tire shaped ring, substantially as described.
7-As a new article of manufacture, a pneumatic rubber tire having its inner
air-tube and canvas-covered retaining-envelope integral, substantially as described.
8-As a new article of manufacture, a pneumatic tire having its retaining-
envelope formed of canvas-covered compressed rubber provided with a rubber
web A forming with the said envelope the inner air-tube, substantially as
described.
9-As a new article of manufacture, a pneumatic tire having its retaining-
envelope formed of canvas-covered rubber with the rubber compressed and
thickened toward the longitudinal center of the tread portion of the tire and
provided along the said thickened portion with a rubber web A forming with the
said envelope the inner air-tube, substantially as described.
10-In combination, a slotted felly D and a pneumatic tire having an inner air-
tube and an outer retaining envelope formed of canvas-covered rubber provided
along its edges with wedge shaped beads E to enter the slot in the felly and fasten
the tire in place, substantially as described.
11 In combination, the hollow slotted felly D and a pneumatic tire having an
inner air-tube and an outer retaining-envelope formed of canvas-covered com-
pressed rubber thickened toward its edges and provided along the same with
beads E to enter the slot in the felly and fasten the tire in place, substantially as
described.
12 In combination, a slotted felly D and a pneumatic tire having its inner
air-tube and canvas-covered retaining-envelope integral, said envelope having
beads along its edges to enter the slot in the felly and fasten the tire in place,
substantially as described.
13-In combination, the slotted hollow felly D and a pneumatic tire comprising
a retaining-envelope formed of canvas-covered rubber with the rubber compressed
and thickened toward the longitudinal center of the tread-portion of the tire and
provided along the said thickened portion with a web A forming with the said
envelope the air-tube, beads E along the edges of the retaining-envelope to enter
the slot in the felly and fasten the tire in place, and an outer covering C clamped
along its edges between the said felly and retaining-envelope, substantially as
described.
Dated this 7th day of June 1892.
W. P. THOMPSON & BOULT,
Agents for the Applicant.