Improvements in Pneumatic Tyres.
Year: 1897

page_text: Date of Application, 28th Oct., 1897-Accepted, 8th Jan., 1898
COMPLETE SPECIFICATION.
Improvements in Pneumatic Tyres.
I, JOHN WILLIAM MCDOUGALL, of Napier, in the Colony of New Zealand,
Journalist, 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 used upon bicycles and the like and its
object is to provide a tubeless tyre or outer cover which may be readily, effec-
tively and inexpensively secured upon the rim of a wheel.
In effecting the object of the invention I make the cover in the shape of an
endless band, the edges of which are cut or moulded into dovetails, serrated, or
fashioned with any other suitable conformation, so that when brought together
they may lock or engaged with one another to form an endless tube. The inner
inflation tube in a collapsed condition is inserted in the cover after which they are
placed upon the rim and the dovetailed edges locked together. The inner tube
is then inflated to expand the cover, and, drawing the dovetails closely together;
to keep the cover from being forced off. Creeping of the tyre may be prevented
by forming transverse ribs or projections on the outside of the cover, which ribs
or projections will drop into or engage with transverse corrugations in the rim;
and the cover may be made into a tubeless tyre by affixing upon one side of the
interior of the cover a rubber tongue so that when both edges of the cover pre
brought together and their edges are locked the overlapping rubber tongue les
closely over the joints of the dovetails, making the whole airtight.
The edges wherein the dovetails are formed may be thickened to give increas
strength and bearing surfaces.
By my invention the cover completely encloses the inner tube, thus saving it
from contact with the rim, and from danger of chafing or puncture by the heads of
the spokes.
A tyre made according to my invention may be more easily put on and taken
off the rim than is the case with the tyres which are secured by wires.
In order that my invention may be most easily understood reference will be
made to the accompanying drawings whilst giving a description in detail.
Figure 1 is a section of the cover and inner tube constructed with dovetails to
unite the edges of the tube.
Figure 2 is an external view of a portion of the same cover, showing the
dovetails.
Figure 3 is a plan of a portion of the same cover opened out.
Figure 4 is a section of the cover when used as a tyre, without an inner tube.
Figure 5 is a section of the cover with portions over-lapping the dovetails inside
and outside.
Figure 6 is a plan of a portion of the same cover opened out.
Figure 7 is a section of the cover with the edges thickened externally to
strengthen the dovetails.
Figure 8 is an external view of a portion of the same cover showing the dove-
tails and thickened edges.
Figure 9 is a section of the same with a flap covering the dovetails.

page_text: Figure 10 is a section of the same with an inner tube.
Similar letters of reference indicate corresponding parts throughout the views.
Describing more particularly Figures 1, 2, and 3 the cover (a) entirely encloses
the inner tube (b) and is thickened at its edges (a) wherein the dovetails (2) and
their corresponding recesses (³) are formed. The dovetails may be stiffened and
strengthened by ribs (a) two of which are shewn by dotted lines on Figures 1
and 2. The ribs (a¹) are made to engage with corrugations formed in the rim of
the wheel to prevent the tyre "creeping or moving upon the rim in the direction
of its length.
On Figure 4 the inner tube is dispensed with and the cover as illustrated used
for a tyre without an inner tube, the joints of the dovetails being made airtight by
the overlapping tongue or strip (c) which is united to or made solid with the cover
at (c). The tongue is lubricated with soft soap by preference, but glycerine,
vaseline, or other similar lubricant may be used to assist in making a thoroughly
airtight joint.
On Figures 5 and 6 the recesses for the dovetails are not cut right through the
cover, but the web (5) unites and strengthens the dovetails and when closed as a
tube covers and overlaps the joints of the dovetails.
On Figures 7 and 8 the cover is thickened externally at (a), and as shewn on
Figures 9 & 10 may be provided with a tongue (c) or inner tube (b);
In each case the thickened portion (¹) of the tyre is placed in the rim of the
wheel.
I
The thickening of the cover may be effected during the manufacture of the cover
and the dovetails afterwards cut, or the cover may be manufactured as a band of
equal thickness throughout and the thickness afterwards added.
"I have shewn the methods which I prefer of strengthening the dovetails, but other
means may be employed, as for example strengthening pieces may be either inserted
within the body of the cover or cemented thereto and made of rubber, cork, metal,
or other suitable substance. Such strengthening pieces may surround the recesses
of the dovetails, or they may traverse the whole length of the tyre, or may be
arranged in any other manner which will prevent the dovetails from buckling
under considerable air pressure.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a tyre a cover having its edges serrated to lock its meeting edges together
said cover entirely surrounding and protecting the inner tube and said edges being
strengthened to resist air pressure, substantially as set forth.
2. In a tyre a cover having its edges serrated to lock its meeting edges together
and having a tongue to make an airtight covering over the joints of the serrations,
substantially as set forth.
3. In a tyre a cover having its edges serrated to lock its meeting edges together
said serrations being strengthened by ribs which fit into the rim of the wheel and
keep the tyre from creeping, substantially, as set forth.
4. In a tyre a cover having its edges serrated to lock its meeting edges together
said serrations being strengthened by a web uniting the serrations and overlapping
the joints of the same, substantially as set forth.
5. A pneumatic tyre consisting of parts constructed combined and operating
substantially as and for the purposes set forth herein and illustrated on the accom-
panying drawings.
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