Improvements in or relating to Pneumatic Tyres, and Machinery Used in the Manufacture thereof.
Year: 1895

page_text: Date of Application, 21st Aug., 1895
Complete Specification Left, 21st May, 1896-Accepted, 4th July, 1896
Improvements in or relating to Pneumatic Tyres, and Machinery
Used in the Manufacture thereof.
THOMAS SLOPER of 11, 12, 14 and 15 Brittox Devizes in the County of Wiltshire
House Furnisher etc. do hereby declare the nature of this invention to be as
follows:-
If the rubber forming the inner tube of a pneumatic tyre is under compression
it will be less liable to puncture & in the event of a puncture the hole will generally
close up & prevent the air from escaping.
It has been suggested that the inner tube should be made longer or with an
excess of material in the form of waves so that inflation shall cause the rubber to
be compressed, but this does not prove satisfactory for inner tubes, as the excess
of rubber is liable to work up into folds, & moreover the tube is difficult to put in
place.
I find it is possible to make a tube the rubber of which is under compression
& which is the proper size for the cover.
In order to attain this result I take a
vulcanized rubber tube of large size (say for example a 2 inch tube for a 1 inch
tyre) and I put into this a rod or core of smaller diameter (say 1 inch). I then
close the ends of the rubber tube and exhaust it of air inside. The pressure of the
atmosphere then causes the rubber tube to be compressed & to be reduced in size
until it fits the core which is inside. In order to retain the tube in this condition
I wind or braid and solution on to it a tape or web of india rubber or fibrous
threads under tension.
If it is desired that a portion only of the tube should be under compression.
I solution on a strip of fabric or rubber to that portion only.
Sometimes I solution nonelastic tapes on to the rubber tube longitudinally &
I then, turn the tube inside out before putting the core inside. These tapes may.
be removed if desired after the restraining material has been applied.
When the tube is on the core and before exhausting the air I sometimes draw
two such tapes in opposite directions in order to distort the rubber of the tube
before compressing it.
I find that a metal tube perforated with small holes forms a convenient core. If
desired the core may be circular or spiral in form, or it may be made in the form
of a ring of some material which can afterwards be melted or by other means.
removed through the valve hole or through a special aperture made for the
purpose.
The tube may be thicker on one side than the other in which case the thinner
part of the tube would probably be compressed most. By manipulation when on
the core one part of the tube may be caused to be under more compression than
another.
A compressed tube made as described may be strengthened by the addition of
one or more larger tubes solutioned on to it under compression in which case the
tube first made would be used as a core for the second tube, & the latter would be
caused to adhere to the first tube by exhausting the air inside & winding on
restraining material as before. If required outside air pressure may be applied
until the solution between the two tubes has set. By thus building up the tube
what is know as a single tube tyre may be made having rubber under compression.

page_text: It may sometimes be an advantage to vulcanize the rubber tube in a corrugated
mould before it is compressed.
The invention is capable of considerable modification for instance it may be
applied to the manufacture of outer covers for pneumatic tyres. A band or cover
may be made of the ordinary size containing the usual restraining material & an
outer cover of rubber which has previously been vulcanized in a larger size mould,
may be shrunk on to the cover by exhausting the air from between the two sections
after having applied a layer of solution, or by applying exterior air pressure in
addition if required or the sections may be further secured together by a few rows
of stitching.
A special machine may be used for applying the thread or other restraining
material in a particular manner or for making a web for after application to the
compressed rubber, the object being to so arrange the restraining material that it
shall not interfere with the speed of the tyre, but shall tend to increase it if
possible.
Dated this 10th do of An 1905
THOMAS SLOPER.
Improvements in or relating to Pneumatic Tyres, and Machinery
Used in the Manufacture thereof.
I, THOMAS SLOPER, of 14 and 15 Brittox, Devizes, in the County of Wilts,
House Furnisher, 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 :-
If the rubber forming the inner tube of a pneumatic tyre is under compression it
will be less liable to puncture, and in the event. of a puncture the hole will
generally close up and prevent the air from escaping.
It has been suggested that the inner tube should be made longer, or with an
excess of material in the form of waves so that inflatiou shall cause the rubber to
be compressed, but this does not prove satisfactory for inner tubes, as the excess
of rubber is liable to work up into folds, and moreover the tube is difficult to put
in place.
According to my invention I make a tube the rubber of which is under
compression, and which is the proper size for the cover.
The invention will be best understood by reference to the accompanying
drawings in which ;-
Fig. 1 is an elevation of a portion of one of my improved pneumatic tyres in
course of construction together with a portion of the perforated core or mandrel
on which it is formed.
Fig. 2 is a similar view of the same portions of tyre and core at a more advanced
stage of the manufacture.
Fig. 3 is a cross-section on the line 3-3 of Fig. 2.
Fig. 4 is an elevation showing portion of the tyre after it has been removed from
the perforated core; this view serves to illustrate the difference between the tyre
when in its normal condition and when in its compressed condition.
Figs. 5, 6 and 7 are views showing the manner in which I construct my improved
tyres on a spiral or flexible and collapsible core or mandrel.
Like letters indicate like parts throughout the drawings.
In carrying my invention into practice in the manner illustrated in Figs. 1 to 4
inclusive I take a vulcanized rubber tube A. of larger diameter than what is
required in the finished tyre (say for example a 2 inch tube for a.14 inch tyre)
and I insert into this a hollow perforated core or mandrel B whose external

page_text: diameter is smaller than the internal diameter of the tube, the ends of the core B
being closed except for a connection with a suitable suction pump or exhauster.
The ends of the tube A are then hermetically sealed so that no air can pass into
it and the exhauster is operated so as to exhaust the air from within the core B
and also by way of the perforations B' from within the tube A which, by the
atmospheric pressure is thereupon caused to fit tightly around the core B. As the
tube A is now of a smaller diameter than originally the rubber is in a state of
compression; in order to retain it in this compressed condition I wind or braid and
solution on to it a tape or web of india-rubber under tension or a tape, canvas, or
as shown in Figs. 2, 3 and 4, a thread C of fibrous or other unstretchable
material; the word "thread" hereinafter employed is intended to include any
unstretchable or substantially unstretchable canvas tape, "twist fabric "
hereinafter mentioned, filament wire or device wound or braided upon the tube A
to prevent the latter from expanding and re-assuming its normal cross-sectional
area or length or both. If it is desired that only a portion of the tube A should be
in compression say for example the tread portion, I solution a strip of unstretchable
fabric or rubber in tension on to that portion only.
66
"
By suitably working the rubber towards certain parts of tube A. while it is
tight upon the core B and before the "thread
or other restraining material is
applied, I may cause these parts to be more compressed than the other parts or in
this same manner I may arrange matters so that in the finished tyre one portion
(advantageously the tread portion) will be greatly compressed and other portions
not at all compressed, the subsequent application of the "thread" canvas
unstretchable material ensuring that these conditions will be maintained.
or
Before inserting the core B into the tube A I sometimes solution to diametrically
opposite sides of the latter unstretchable tapes D D and turn the tube inside-out
so that the tapes will then be at the inside of the tube. The core B is then inserted
into the tube A and before the air is withdrawn from the latter the tapes D D'
are pulled in respectively opposite directions as shown in Fig. 2 so as to distort the
rubber before it is compressed. The air is then exhausted from within the core B
and tube A so that the latter is caused to closely embrace the former and while the
tube is still in this reduced and consequently compressed condition I wind round
either transversely or circumferentially or both and solution or otherwise apply to
it the "thread" C in say the same manner as before described. After this air
may be admitted into the core B and tube A and the core withdrawn from the
tube A. the "thread" C then preventing the expansion of the tube into its normal
uncompressed condition. The tension of the rubber caused by its distortion in the
manner previously described causes the rubber to, as it were, make an effort to
regain its undistorted condition and in doing so, it draws the "thread C which
was wound on the distorted tube A substantially perpendicularly to the axis of
the latter aslant in the manner shown in Fig. 4. This I find a considerable
advantage as it allows the tube A when subsequent inflated, a certain degree of
elasticity (the limit of elasticity being when the "thread" is again perpendicular
to the axis of the tube) which enables it to slightly expand and better fit the cover
in which it is enclosed. The tapes D D¹ if desired may then be removed from
the tube.
"
Instead of using tapes for distorting the tube A I may attain the same result by
employing a core having two or more parts longitudinally movable in relation to
each other, the distortion being effected by moving diametrically-opposite parts of
the core in reverse directions after the air has been exhausted.
After the tube A has been removed from the core B its two ends may be secured
together in the usual manner to form a hollow ring ready for application to a
wheel.
In constructing a tyre in the manner shown in Figs. 5 and 6 I provide a core or
mandrel B' which is formed of a spirally wound metal ribbon of which each
convolution overlaps one of the convolutions next adjacent to it. On to this
mandrel place a vulcanized rubber tube A the ends of which are next closed

page_text: ་་
over the ends of the core B³, an opening being left say in one end to attach a
suction pump or other exhauster to the tube. The air is then exhausted from
within the core B' and tube A so that the pressure of the atmosphere causes the
tube A to tightly embrace the core, and by suitably manipulating the latter,
through the tube A the core may be reduced both in diameter and length (or in
length only as the case may be), the tube all the while closely hugging the core B'.
By these means the diameter and length of the tube A are decreased to an extent
corresponding to the core B³, so that the rubber is then in a compressed condition.
In order that the tube B may be retained permanently in this condition I bind it
with "thread" C in the same manner as previously described with reference to
Fig. 2. One or both ends of the tube A may then be opened and the core B³
removed, the rubber thereafter remaining in its compressed condition.
The two ends of the tube may then be secured together in the usual manner to
form a hollow ring.
Should it be desired that one part of the tube be more in compression than
another as for example may be advantageous at the tread portion this may be
effected by "working" the rubber, when upon the core, towards the part at which
the greater compression is required.
Instead of compressing the tube A while it is in a straight length as before
explained in connection with Figs. 5 and 6, I may first form it into a ring (a
portion, of which is represented in Fig. 7) and then compress it while in that form.
To effect this 1 first insert the spirally-wound core B2 into the tube A while both
are straight, in the same manner as last described and then bend the tube and core
into a ring and solution or otherwise permanently secure the two ends of the tube
together. A hole A' may then be formed in the tube A at the part at which the
two ends of the spiral core B' meet (this hole serving for the subsequent
attachment of the usual non-return valve) and to this hole may be connected an
exhauster by which the air is exhausted from within the tube A. By suitably
manipulating or "working" the rubber and its core B when the air is thus
exhausted the ring may be considerably reduced in size either circumferentially or
in transverse sectional area or both, so that the rubber will be correspondingly
thickened and compressed either uniformly throughout or at the tread or other
parts according to the manner of "working "the rubber. The endless rubber
tube is then of approximately the finished size and to prevent it from expanding
when the air is subsequently allowed to enter it I solution or otherwise secure to
its inner circumference (that is, the part which is to be directly applied to the
wheel rim) a restraining ring E of wire, tape or other suitable unstretchable
material. The endless tube together with the restraining ring E is then bound
with "thread" C so as to prevent the tube from materially increasing in cross-
sectional area when air is allowed to enter or forced into it.
The tube A may then be disconnected from the exhauster and air allowed to
enter the restraining material C and E preventing it from again assuming its
original uncompressed condition.
The spirally wound, core B' may then be removed from the interior of the tube A
by winding it through the "valve-hole " A in the manner indicated in Fig. 7,
which operation completes the tube. Or a slit may be made in the tube through
which the core may be withdrawn and this slit may afterwards be closed by a
patch of canvas or other material.
Instead of the collapsable core B2 being formed of a single spirally wound
ribbon as previously described it may be formed of two or more, the spaces
between the convolutions of one coil being arranged to break joint with those of
the other coil or coils.
I find it advantageous to make transverse slits at intervals in one edge of the
ribbon forming the spirally wound core, as this allows the convolutions to slide one
over another with greater freedom, besides which it enables a wider ribbon to
be used and consequently provides a more rigid core than would otherwise be
possible.

page_text: For the sake of clearness I have, in the drawings, shown the restraining
material C in the form of a "thread" but I do not confine myself to the use of
any particular material, as I may use various materials for the purpose specified,.
one particularly suitable being the "twist fabric" described in my previous.
Letters Patent No. 20563 1894.
In constructing a stout rubber tube such as those used on carriages, motor
vehicles and the like I may assist the compression of the rubber by withdrawing
the air from within the tube while the latter is located in a chamber containing
air under pressure.
If desired I may, instead of the cores B and B before described, use a core
of some material which at the completion of the tyre may be melted and run
out through the valve hole A' or through a special aperture made for the
purpose.
The wall of the tube A instead of being of uniform thickness throughout may be
thicker at one part than another.
A compressed tube made as before described may be strengthened by the
addition of one or more larger tubes solutioned on to it under compression, in.
which case the tube first made would be used as a core for the second tube and
the latter would be caused to adhere to the first tube by coating the latter with
solution, exhausting the air from between the two tubes and winding on restraining.
material as before.
If required outside air pressure may be applied until the solution between the
two tubes has set. By thus building up the tube what is known as a single tube.
tyre may be made, having rubber under compression.
It may sometimes be an advantage to vulcanize the rubber tube in a corrugated
mould before it is compressed.
This invention is capable of considerable modification for instance it may be
applied to the manufacture of outer covers for pneumatic tyres. A band or
cover may be made of the ordinary size containing the usual restraining
material and an outer cover of rubber, which has previously been vulcanized
in a larger size mould may be shrunk on to the cover by exhausting the air
from between the two sections after having applied a layer of solution or by
applying exterior air pressure in addition if required, or the sections may be
further secured together by a few rows of stitching.
"
A special machine may be used for applying the "thread or other restraining.
material in a particular manner or for making a web for after application to the
compressed rubber, the object being to so arrange the restraining material that it.
shall not interfere with the speed of the tyre, but shall tend to increase it if
possible.
Having now particularly described and ascertained the nature of the said inven-.
tion and in what manner the same is to be performed 1 declare that what I
claim is ;-
1. The manufacture of a compressed india-rubber tube or tyre cover according
to any of the methods substantially as described.
2. In the manufacture of a compressed india-rubber tube placing a rubber tube
on a core or mandrel of smaller external diameter than the internal diameter of
the tube closing the ends of the tube exhausting the air from within the tube or
applying external pressure to it or both so as to reduce the diameter of the tube
and then binding the tube with restraining material and removing it from the core
substantially as described.
a
3. The herein described method of making a contracted endless rubber tube
consisting of placing a plain vulcanized rubber tube on a collapsable core (or
core of smaller external size than the interior of the tube) bringing the ends of
said core together joining the rubber tube causing the air pressure outside to be
greater than that inside, applying.restraining material and afterwards withdrawing
the core through a hole or slit in the tube substantially as described.

page_text: 4. In the manufacture of a compressed india- rubber tube as set forth in the last
preceding claim distorting the rubber by moving parts of it in respectively opposite
directions before applying the restraining material substantially as and for the
purpose described with reference to Figures 2 and 3 of the accompanying
drawings.
5. An india-rubber tube retained in a state of compression by a winding of
restraining material the convolutions of which when the tube is in a normal or
non-distended condition are at angle to the axis of the tube and when the tube
is distended are approximately perpendicular to the axis substantially as described
with reference to Fig. 4 of the accompanying drawings.
6. In the manufacture of a compressed india-rubber tube as set forth in Claim 2
the employment of a perforated core such as B B' substantially as described and
illustrated in the accompanying drawings.
7. In the manufacture of a compressed india-rubber tube placing a rubber tube
on a core formed of a spirally-wound resilient ribbon closing the ends of and
exhausting the air from within the tube or applying external pressure to it or both
so as to reduce the diameter of the tube and core and then binding the tube with
restraining material and removing the core therefrom substantially as described.
8. In the manufacture of a compressed india-rubber tube placing a rubber tube
on a core formed of a spirally-wound resilient ribbon closing the ends of and
exhausting the air from within the tube or applying external pressure to it or both
reducing the length of the core and tube and binding the tube with restraining
material and removing the core therefrom substantially as described.
9. In the manufacture of a compressed india-rubber tube the employment of a
core formed of a spirally-wound resilient ribbon substantially as described.
10. In the manufacture of a compressed india-rubber tube placing a rubber tube
on a collapsable core or one having its external diameter smaller than the internal
diameter of the tube closing the ends of and exhausting the air from within the
tube or applying external pressure to it so as to reduce its diameter "working
the rubber so that one part may be more compressed than another and removing
the core substantially as described.
Dated this 18th day of May isas
"
THOMAS SLOPER.
Boult & Wade,
Agents for the Applicant.