Improvements relating to the Manufacture of Pneumatic Tires, and to Apparatus therefor.
Year: 1894

page_text: Date of Application, 12th Apr., 1894-Accepted, 19th May, 1894.
COMPLETE SPECIFICATION.
Improvements relating to the Manufacture of Pneumatic Tires, and
to Apparatus therefor.
I, AI BERTRAM SHAW, of Medford, Massachusetts, United States of America,
Mechanic, 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 especially to the construction or manufacture of the inner
or inflatable tubing employed for pneumatic tires for bicycles and other vehicles,
in such a manner that when accidentally punctured, it will automatically seal or
close the opening thus formed and prevent the escape of air.
In carrying out my improvements I make use of means which will be readily
understood from the following explanation, reference being had to the accompanying
drawing, in which
Figure 1 is a plan or top view of the bench used in my process with a section of
deflated tubing thereon ;
Figure 2 is a like view showing one end of the tube stretched and secured to
the bench;
Figure 3 is a plan or top view showing the guide wires inserted in the tube and
the plunger in position to be entered therein;
Figure 4 is a plan or top view showing the tube stretched laterally;
Figure 5 is a vertical transverse section of the parts as shown in Figure 4;
Figure 6 is a like view showing the extra ply attached to the tube;
Figure 7 is a vertical transverse section of the completed tube;
Figure 8 is a plan or top view showing an alternative method of securing the
tube to the stretching wires.
Figure 9 is a longitudinal section of a portion of rubber tubing showing the
folding tool in position;
Figure 10 is a like view with the end of the tube turned outward over
the tool;
Figures 11, 12 and 13 are longitudinal sections illustrating steps in the process
of forming the joint of the tire ;
Figure 14 is a like view of the finished joint; and
Figures 15 and 16 are end elevations of the tool.
Like letters and figures of reference indicate corresponding parts throughont
the drawing.
A represents a bench of any suitable construction. At each end of the bench a
determined distance apart studs are arranged.
A section of rubber tubing of the ordinary quality employed in manufacturing
bicycle tires is disposed on the bench, and one end, d, thereof is spread or stretched
laterally and secured by nails, 1, (see Figure 2) to the bench. This lateral
stretching is continued at this point to nearly the capacity of the material. The
free end, g, of the tube is then grasped and the tube stretched lengthwise and the
said end, 9, also stretched laterally and secured by nails, f, to the bench the same
distance apart as the nails, f.
The process of stretching thus far causes the centre of the tube to sag or be
much narrower than at the ends, as shown in Figure 3. It is necessary to stretch
all portions of the said. tube laterally a like amount and to accomplish this result I
employ the following apparatus which successfully overcomes all the difficulties of
friction against the tube when inserting a rigid spreader therein.

page_text: Two wires, h, are passed through the tube, the ends of the said wires being
hook-shaped and clasped around the pins b, on the bench. A flat board or
metallic plate, H, is now employed as a spreader or plunger. This plate has its
end slightly reduced at, m, and its edges are grooved longitudinally at, p, to receive
the wires, h.
Entering the said wires in the groove the plunger can readily be forced through
the tubing, B, the wires acting as a track therefor and serving to reduce the friction
of the plunger on the rubber so that no further longitudinal stretch is imparted to
the tube while it is forced laterally outward until all parts are stretched equally
and the position shown in Figures 4 and 5 is assumed.
The tubing is now flattened, its vertical internal diameter being only the
thickness of the spreader, H. To one face of the flattened tube and entirely
covering the same I cement a sheet of rubber, t, in its normal or undistended
condition where it is allowed to remain until the cement is firmly dried or set. The
spreader, H, is withdrawn from the tube which is detached from the bench by
removing the nails, f, and the said tube is withdrawn from the wires, h, releasing
entirely the strain on the body of the tube which contracting upsets or compresses
the sheet, t, to a marked degree. As some resistance is offered by the sheet, t, the
material of the main tube cannot recover entirely and the tube in this condition is
distended or warped considerably from a cylindrical form.
I now turn the tube outside in so that the sheet, t, is at the tread portion of
the completed tube as shown in Figure 7. The ends of the tubing are joined
together to form the tire by any suitable means and the tire can be inflated in the
usual manner.
I preferably, however, employ the means illustrated in Figures to 16 inclusive
for joining the ends of the tube to form the tire; much difficulty being experienced
with the ordinary means in accomplishing this as the upset or contracted ply causes
the ends of the tube to cockle and, when telescoped or overlapped to join them,
the cement will not take on all parts of the surface and the cockling or distortion
renders it extremely difficult to manipulate.
It is impracticable to hold the ends of the tube in shape by a former inserted
therein, as such former would have of necessity to remain within the tube and
interfere seriously with its elasticity.
In the figures referred to, K, P, represent the tube ends. In joining these ends
I encircle one thereof, as K, with a cylinder, T, of tin or similar flexible metal,
the said cylinder being split longitudinally as at, 25, in Figure 15. The cylinder
is disposed an appreciable distance from the end, 30, of the tube which is turned
inside out and folded backward over the cylinder as in Figure 10, the cylinder
being of sufficient rigidity to support the tube in this position. The opposite
end, P, is then drawn over the folded end, 30, its mouth 35, being expanded
sufficiently for this purpose and carried about one half the length of the folded
portion, 30, as in Figure 11.
The cement, 40, is now applied to the outer face of the mouth, 35, and the
end, 30, is again bent backward or outward onto the said cemented portion as
shown in Figure 12, so that now outside of the cylinder, T, there are three
thicknesses of tubing between which and the body of the tubing the said cylinder
is interposed. As soon as the cement sets, the operator grasping the ends of the
tube draws the overlapped ends from the cylinder the joint, W, assuming the form
shown in Figure 13.
The cylinder or tool, T, is now spread and removed from the tube end, K, the
joint, W, is then finished by chamfering or rubbing down the outer surface or
by any other suitable means for bringing it to the same exterior diameter as the
remainder of the tube.
Instead of using the split tin cylinder, a form of tool, V, like that shown in
Figure 16 may be employed, which comprises two semi-cylindrical sections hinged
together.
This tubing, when disposed within the casing and inflated, has all the properties

page_text: of the ordinary tube. Should the tire be accidentally punctured, it will be found
that, as soon as the puncturing article is withdrawn, the tension of the outer body
of the tube acting upon the upset inner portion or sheet, t, will cause the opening
formed by the said article in the said inner portion or sheet to be immediately drawn
together or sealed thereby and prevent the escape of air from within the tube.
As specified, the tube, B, being still expanded or stretched slightly after being
attached to the ply or sheet, t, the opening formed by puncturing will enlarge or
flare somewhat. To overcome this when. the tube has been formed as above
described, I cement a ply, v, of linen or thin canvas or similar textile material.
(see Figure 7) to the tread portion of the outer face of the tire or so much thereof
as will cover the area of the sheet, t.
When punctured through this reinforcing strip which does not in any manner
affect the sealing qualities of the inner ply, t, the said strip, v, will prevent the
flaring of the opening in the main or outer tube, B, as it serves to hold all portions
thereof and prevent further stretching.
In Figure 8 the ends of the tube, B, are secured by tying at, w, directly to the
rods or wires, h.
I do not confine myself to any particular form of wires or ways or of the
plunger or stretcher, nor do I wish to be confined to the means described for holding
the tube when stretched.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1st. That improvement in the method of making inflatable tubing for
pneumatic tires which comprises stretching the tube laterally at one end and
securing the said end to a support; then stretching the said tube longitudinally
and its opposite end laterally and securing it to a support; disposing a track or
way longitudinally within the said tube; inserting a spreader in the said tube on
the said way whereby the tube is stretched laterally throughout its length;
securing a portion of rubber in its normal condition to a face of the said tube; and
then releasing the said tube whereby the said portion of rubber is upset or
contracted.
2nd. That improvement in the method of making inflatable tubing for pneumatic
tires which comprises stretching the said tube laterally and longitudinally and
holding the same by securing the ends thereof to a support; securing a sheet of
rubber in its normal condition to the whole or a portion of the surface of the said
tube; releasing the tube and turning it outside in.
3rd. That improvement in the method of making inflatable tubing for pneumatic
tires which comprises stretching a section of rubber tubing both lengthwise and
laterally, and holding the same by securing the ends thereof to a support;
disposing detachable slide ways within the said tube; entering a plunger into the
tube on the said ways; securing a sheet of rubber in its normal condition to a
portion of the outer surface of the said tube while in its stretched condition;
removing the tube from the plunger and ways; turning the said tube outside in
and securing a sheet of textile material to its outer surface.
4th. That improvement in the method of making inflatable tubing for pneumatic
tires which comprises stretching a section of tubing longitudinally and laterally
and, while held in such position, securing a portion of rubber in its normal
condition to the outer face of the said tube; turning the tube outside in whereby
the said portion is upset or contracted and securing a portion of textile material to
the outer face of the said tube.
5th. As a new article of manufacture, the rubber tubing having a ply of rubber
in compressed or contracted condition secured to its inner surface and held
thereby, and a ply of textile material secured to the outer surface of the said tube.
6th. The herein described apparatus for preparing rubber tubing for bicycle
and other tires, which comprises a bench or support, flexible ways for insertion in

page_text: the said tubing, devices for attaching the ways to the said support and a plunger
fitted to slide on the said ways.
7th. The herein described apparatus for the purposes specified, comprising
flexible slide-ways adapted for insertion in a rubber tube, devices for securing the
Baid ways to a support and a plunger fitted to slide on the said ways whereby the
tube may be spread laterally, substantially as, and for the purpose, set forth.
8th. The combination, with the support, of the flexible ways h, devices for
detachably securing the same to the support, and the plunger H, grooved to engage
with the said ways:
9th. That improvement in the method of constructing inflatable tubing for
bicycle and other tires, which comprises enclosing one end of the tube in a
detachable cylinder of sufficient rigidity to retain the shape; turning the end of
the said tube inside out and backward over the said cylinder; inserting a portion
of the end thus folded into the companion end of the tube; again turning the said
folded end outward over the said companion end and cementing these parts
together, the plies thus formed being outside the said cylinder, then withdrawing
the plies or folds from the said cylinder and removing the cylinder, substantially as
described.
10th. That improvement in forming the joint between the ends of a flexible
tubing for pneumatic tires, which comprises turning one end of the tube inside out
over a form, drawing the companion end of the tube over the said folded portion ;
again turning the folded end of the tube over the companion end and cementing the
parts together.
11th. The herein described tool for forming a joint in the inflatable tubes for
bicycle tires, which comprises a longitudinally split cylinder adapted to encircle
the said tube and over which an end thereof may be folded.
12th. The split cylinder in combination with the tube end, K, enclosed
thereby.
D. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.