Improvements in Pneumatic Tires.
Year: 1898

page_text: Date of Application, 1st Mar., 1898-Accepted, 23rd Apr., 1898
COMPLETE SPECIFICATION. --
Improvements in Pneumatic Tires.
I, AI BERTRAM SHAW, of Medford, in the County of Middlesex, and State of
Massachusetts, United States of America, Manufacturer, 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 improvements in inner air tubes for pneumatic tires, and
in that class of air tubes which are made separable from the outer casing in order
to place them within or to remove them from said casing, and it relates more
particularly to the manner of forming the ends of the tube, and of connecting said
ends together so as to establish a continuous air passage around the entire tube
when cemented and to permit of quick and easy breaking of the joint between the
ends of the tube, as well as the ease and certainty of making an air-tight joint
between said ends, thus facilitating the insertion or removal of said tube.
The invention consists in forming the air tube with partly closed ends, so that
when joined together the openings in the ends will coincide and form communi-
cation between the ends, and in the re-inforcement of said ends, so as to allow the
joint to be separated without liability of injury to the tube; in the formation of a
tight joint between the ends by the application of cement around the openings
therein; in the formation of the end of the tube so as to reduce the amount of dead
rubber at the joints between the ends, and thus cause an easy riding tire when
riding over said joints, and in minor details of construction as will be understood
by the complete description thereof. The invention is carried out substantially as
illustrated in the accompanying drawings which form an essential part of this
Specification and whereon:-
Fig. 1 represents a plan view of the ends of an inner air tube showing the
preferred manner of cutting the end preparatory to closing the same.
Fig. 2 represents a longitudinal section of the same.
Fig. 3 represents a plan view of the finished ends of an inner air tube as shown in
Figs. 1 and 2, but showing the same partly closed.
Fig. 4 represents a longitudinal section of the tube shown in Fig. 3.
Fig. 5 respresents a sectional view of a portion of a pneumatic tire with an inner
air tube made as shown in Figs. 3 and 4.
Fig. represents a plan view of the ends of an inner air tube, showing a modified
form of my invention.
Fig. 7 represents a longitudinal section of an inner air tube as shown in
Fig. 6.
Fig. 8 represents a perspective view of the ends of an inner air-tube made as
shown in Fig. 6 and showing the preferred relative position of the ends when
joined together.
Fig. 9 represents a sectional view of a pneumatic tire provided with my improved
inner air tube constructed as shown in Fig. 6.
Fig. 10 represents a longitudinal section of the ends of an inner air tube showing
a slightly modified form of my invention.

page_text: Fig. 11 represents a section of another modified form of the end of an inner tube
made in accordance with my invention.
Similar characters of reference refer to similar parts wherever they occur on the
different parts of the drawings.
The tire is composed of the outer casing 1 and an inner air tube 2, which air
tube is separable from the outer casing, and as stated before, my invention relates
to the inner air tube, to the formation of the ends thereof, and to the manner of
connecting said ends together so as to be easily and quickly connected or
disconnected without liability of injury to said ends, and so as to form a continuous
air passage around the entire tube.
I wish it to be understood that the particular kind of construction of the outer
casing forms no part of my present invention, and that my improved inner air tube
may be used in any outer casing in which the air tube is made separate from the
casing and is inserted and removed as desired, also that the ends of the tube may
be partly closed in various ways as will be fully understood by the complete
description herein contained, without departing from the principal feature of my
invention.
The ends of the inner air tube may be made in various ways so as to partly close
the same, but in Figs. 1 to 5 both inclusive, I have illustrated one of the various
ways for accomplishing this result, which seems to me to be the preferred way.
In said figures the tube is flat both before and after it has been vulcanized.
The tube is formed somewhat longer than is required to extend around the tire,
and its opposite ends are then cut so as to form a flap 3 at each end of the tube,
the flap upon one end being on the underside of the tube while the flap at the
opposite end is upon the upper side of the tube. These flaps are formed by
cutting the tube upon the lines 4, 5, 6, 7, 8, 9, and 10, shown in Figs. 1 and 2, or
in a substantially similar manner.
The flap on the underside of one end of the tube is then folded backward on the
broken line 11 against the upper side of the same end of the tube, and is attached
thereto while the flap upon the upper side of the opposite end is then folded back-
ward on the broken line 11 against the under side of the same end of the tube and
is attached thereto forming ends to the tube substantially as shown in Figs. 3 and
4, each end being reinforced on one side by the flap thereon substantially as shown
and for a purpose to be described hereinafter.
By forming the ends of the tube in this manner it will be seen that the tube may
be formed complete with its ends closed prior to vulcanizing any part thereof and
the completed inner tube be vulcanized at one and the same operation in the
vulcanizer. Prior to vulcanizing the inner tube, or after it has been vulcanized, as
desired, the reinforced portions of the ends thereof are provided with the perforations
12 which perforations are so located that they leave a part of the reinforcement on
all sides of the perforations.
The manner of using the inner air tube constructed as thus far described is as
follows:-
The tube is drawn into the outer casing in the usual manner. Cement is applied
to the reinforced portions of the ends of the tube around the perforation therein,
and as the tube is made longer than required to extend around the entire tire it
will be seen that the ends of the tube will over-lap each other and that their
cemented reinforced portions can be brought together and held firmly attached to
each other by the action of the cement, and in such a position that the perforations
12 on said ends will coincide and form open communication between the ends of
the tube.
The two connected ends of the tube are then placed within the casing; the
casing sewed in the usual manner and secured to the rim of the wheel. If it is
desired to remove the inner tube for repairs or for any other purpose it is only
necessary to withdraw the connected ends of the tube from the outer casing in the
usual manner when the cemented joint between said ends may easily be broken by
pulling said ends apart which on account of the reinforcements at said ends may

page_text: be done without liability of tearing the tube. The entire tube may then be with-
drawn from the casing in the usual manner, be repaired and replaced as above
described. This withdrawal and replacing of the tube may be accomplished very
quickly and, on account of the joint being made between two flat cemented surfaces
which rest against each other, it does not require skill to ensure the making of a
perfectly air-tight joint, which can be effected by simply pressing the two ends
between the thumb and fingers without any special manipulation of the tube to
bring said surfaces together. As the ends of the tubes are reinforced on one side
only, and as these reinforcements are cemented together and located within the
centre of the air tube so that they do not come into contact with the inner surface
of the outer casing, it will be seen that there is only a single thickness of the
rubber which forms the inner tube resting against the outer casing; therefore
there is practically no dead rubber at the joint between the ends of the tube to
lessen the resilency of the tire at this place. It will also be seen that there is open
communication formed between the connected ends of the tube by means of the
perforation 12 and consequently there is no liability of penning the air at the ends
of tube which has been found to be a defect in the inner tube with closed ends
now in use.
If so desired the ends of the tube may be constructed so as to be of a single
thickness of rubber throughout as shown in Fig. 10, and the perforation 12 in said
end be reinforced by a separate piece or washer 13 vulcanized thereon as shown in
said figures.
In Figs. 6, 7, 8, and 9, I have shown a modified form of my invention in which
the ends are formed square and partially closed, said ends being made by cutting
one side of the tube shorter than the other side then cutting a perforation 15
in the longer side reinforcing this perforation by means of the reinforcement 16
if so desired, and turning the longer side back upon the shorter side forming a
joint or seam 14 and the perforation 15 as shown in said figures. The tube is
thus formed complete prior to vulcanizing the same, but if so desired the tube
may be first vulcanized with wholly open ends and said ends may afterwards be
partially closed and finished by cementing. Each end of the tube 2 is formed in
this manner and is thus provided with a perforation 15 for the purpose of creating
a continuous air chamber within the inner tube when the ends are joined together
as set forth.
When the inner air tube has been inserted within the outer casing, the ends of
the said tube are joined together so that the perforations in the ends of the tube
coincide and form a continuous annular air chamber within the tube.
I prefer to reinforce the tube around the perforations 15 by means of the
reinforcements 16 made by increasing the thickness of the rubber around said
perforations or by vulcanizing washers of suitable fabric within or upon the tube
at this place substantially as shown.
If so desired the reinforcements 16 on the ends of the tube form comparatively
flat surfaces around the perforation so as to receive cement and thereby join the
ends of the tube together air-tight.
It is a very simple process to form a joint in this manner as the two abutting
surfaces of the reinforcements 16 are pressed together after the cement has been
applied thereto, and any person can easily make a perfect joint in this way even
though inexperienced in such work, as there is no liability of wrinkles or
imperfections.
It has been found by experience, that when the inner air tubes of the tires are
to be drawn into an outer tube or casing they are inserted with greater ease if said
inner tubes are flat, and for this reason said inner tubes are generally vulcanized
flat so that they will naturally assume that shape and will consequently expel the
air as much as possible when their valved inlet is opened. It has also been found
that when a flat elastic tube with square ends is inflated, the expanding of the tube
will cause the center of the ends of the tube to be drawn backward and the outer
edges of the ends of the tube to project making the ends of the tube concaved.

page_text: On this account when I use a flat tube with square ends as shown in Figs. 6, 7,
8, and 9, I prefer to join the ends of the tube together in such a manner that the
flat ends will be in planes at right angles to each other as shown in Fig. 8 so that
the drawing backward and the projecting of the different parts of one end of the
tube, will compensate for the similar action of the other end of the tube, thus
causing as uniform a strain as is possible on all parts of the ends of the tube when
inflated and confined within an outer casing. The result of inflating an inner flat
square ended tube within an outer casing, when the ends have been connected in
the relative positions shown in Fig. 8 has been illustrated in Fig. 9 and it will be
understood that by this manner of connecting the ends of the tube the liability of
overstraining the centre portions of the ends or the 'fulling of the material at the
outer edges of the ends when inflated within an outer tube or casing is
obviated.
By the peculiar manner of forming the partially closed ends of the tube it will be
seen that substantially all parts of the said ends may be made of even thickness with
the other parts of the tube and therefore the resiliency of the tire will be practically
uniform.
as
The manner of using this form of my improved inner tube is the same
described in relation to the form shown in Figs. 1 to 6 both
inclusive.
In Fig. 11 I have shown still another form of my improved inner tube in which
the tube is made cylindrical and is closed at either end by means of a circular
cap 17 having the perforation.15 therein and the reinforcement 16 thereon, which
cap is vulcanized on said tube.
My inner air tube is provided with any of the common and well
known forms of air valves for the purpose of inflating or deflating the same,
but said valve has not been illustrated on the drawings as it forms no essential part
thereof.
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
1st. In a pneumatic tire, an outer casing and an inner air-tube made separate
from the casing and having its ends partly closed and connected together
by cement applied around the perforations in the partly closed ends, whereby a
continuous air-chamber is formed around the entire tube and the joint between the
ends are easily and quickly made and broken, for the purpose set forth.
2nd. In a pneumatic tire, an outer casing, and an inner air-tube made separate
from the casing and having its ends partly closed and provided with reinforcements
around the openings in the ends and connected together by cement applied to
said reinforcements, whereby a continuous air-chamber is formed around the entire.
tube, for the purpose set forth.
3rd. A separable air-tube for a pneumatic tire, having its ends partly closed
and adapted to be connected together to form a continuous air-chamber by means
of cement applied to said ends, for the purpose set forth.
4th. A separable air-tube for a pneumatic tire, having its ends partly closed and
reinforcements around the perforations in the ends, the ends adapted to be
separably joined together.to form a continuous air-chamber by cement applied to
the reinforcements, for the purpose set forth.
5th. A separable air-tube for a pneumatic tire, having a perforation on the
side of one end, and a perforation on the opposite side of the other end, whereby
the ends may be overlapped and connected together to form a continuous air-
chamber in the tube, for the purpose set forth.
6th. A separable air-tube for a pneumatic tire, having a perforation on the side
of one end, a perforation on the opposite side of the other end, and reinforcements
around said perforations, whereby the ends may be overlapped and cement

page_text: applied to the reinforcements to form a continuous air-chamber, for the purpose
set.
7th. A separable air-tube for a pneumatic tire, with its ends formed with a flap
turned back upon the tube and vulcanized thereon to form reinforcements thereto,
and perforated through said reinforcements, the ends of the tube reinforced and
perforated on opposite sides, for the purpose set forth.
8th. In a pneumatic tire, an outer casing, combined with an inner air-tube
having its ends overlapping each other and separably cemented together and
each of the opposite ends formed with a flap turned back upon the tube,
vulcanized thereon to form reinforcements thereto and perforated through said
reinforcements to form a continuous air-chamber therein, the opposite ends of
the tube being reinforced and perforated on opposite sides, for the purpose
set forth.
1
1 1000
D. YOUNG & Co.,
11 and 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.
D. YOUNG & Co.,
11 and 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.