Improvements in Pneumatic Tyres.
Year: 1895

page_text: Date of Application, 29th Oct., 1895-Accepted, 30th Nov.,
1895
CUMI DEI
Improvements in Pneumatic Tyres.
We, MARTIN Luther Warson, of No. 47 Pomeroy Avenue, Salesman, and
EDWARD FORBES PICKETT, of 397 Grant Street, Architect, both in the City of
Buffalo, in the County of Erie and State of New York, United States of America,
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 more particularly to pneumatic tyres which consist
essentially of an inflatable tube having a flat tread or bearing face.
In such tyres as hitherto constructed, the tread, while flat in the free or
deflated condition of the tyre, expands to an oval or convex form upon being
inflated and the advantages sought to be gained by the use of a flat tread are,
therefore, not realized. This tendency of the tread to assume an oval form is
especially objectionable when a protecting shoe or armour is applied to the same to
prevent puncturing of the tyre by sharp objects, in which case the bulging of the
tread raises and detaches the edges of the shoe or armour from the tread, allowing
the grit to enter between the latter and the shoe and causing the ultimate separation
of the shoe from the tyre.
One of the objects of our invention is to so construct the tyre that the tread
maintains its flat form when the tyre is inflated, thus obtaining the advantages of
such a tyre and enabling an armour or shoe to be reliably retained thereon.
Our invention has the further objects to provide the tyre with a shoe or
armour which effectually protects the tyre against puncture without impairing its
resilience, and to construct the tyre in such a manner that when inflated, its
side walls remain practically within the longitudinal edges of the tread or
armour whereby tacks or other sharp objects are prevented from reaching those
walls.
In the accompanying drawings
:-
Figure 1 is a sectional perspective view of a portion of a pneumatic tyre
containing our improvement, showing the tyre in its deflated condition.
Figure 2 is a similar view, showing the tyre in its inflated condition.
Figure 3 is a view similar to Figure 1, showing the protecting shoe applied to
the tyre.
Figure 4 is a detached perspective view of a portion of the shoe.
Figure 5 is a sectional perspective view, showing our improvement in connection
with a double tube tyre.
Similar letters of reference refer to similar parts in the several figures.
Referring to Figures 1 to 4, A is the hollow tyre which consists of a tube
having a flat tread and a convex or rounded seating side a which lies in the groove of
the rim. The tread is provided between its flat marginal portions b with a longi-
tudinal groove or depression c extending continuously around the tyre, and the
corners d formed by the junction of the tread and the side walls e of the tyre
to render said corner portions
are thickened, as shown in the drawing, so as
practically non-expansible. The depressed or grooved portion of the tread is
considerably thinner than the corners, so as to yield when the tyre is inflated.
By this construction, upon inflating the tyre, only the depressed central portion of
the tread is expanded and its outer surface is brought in line or flusb with the flat
marginal portions of the tread, as shown in Figure 2, thereby rendering the tread

page_text: "
substantially flat and smooth from edge to edge. As the thickened corners of the
tread are practically unaffected by the inflation of the tyre, they check the
expansion of the depressed central portion of the tread and prevent the same from
bulging into an oval or convex form. The tread is recessed or depressed to such a
depth and the corners are thickened to such an extent that the expansion of the
depressed central portion is arrested when in line with the marginal portions of the
tread. In order to produce a perfectly flat tread-face on inflation, the concave
bottom of the longitudinal depression is joined with the flat marginal portions by
gentle or gradual ogee curves, as shown.
Our improved tyre can be molded of rubber in one piece like an ordinary
cylindrical tyre and at substantially the same cost.
When a tyre thus constructed is used in connection with a metallic or other
armour for protecting it against puncture the armour is not bulged or crowned in
the middle and eventually separated from the tyre but remains flat like the tread
of the tyre thereby avoiding loosening of its edges and enabling it to remain
securely upon the tyre.
Any suitable flat annular armour or protecting shoe may be applied to the tyre
but we prefer that which is shown in Figures 3 and 4 of the drawings. This shoe
consists of an endless band F of rubber and transverse plane or flat strips g of very
thin steel or other suitable hard and resilient material embedded in the rubber
band. In the drawing the strips are exaggerated for the sake of clearness. These
strips are arranged flush with each other and closely together but are slightly
separated by very thin films of rubber which enter between adjoining strips.
The annular series of transverse strips extends throughout the endless band and
forms therewith an annular flexible armour which effectually prevents tacks and
other sharp objects from reaching the tread and puncturing the same. Adjacent
strips are free to yield individually as they do not rest one upon the other or are
otherwise connected except by the rubber in which they are embedded, and the
tyre is therefore practically as resilient as one having no such armour. Any one
or more of the strips can thus yield in passing over an obstruction without
affecting adjacent strips, thus indenting the tyre to a correspondingly small extent
and reducing the jar or vibration received by the machine to a minimum.
The shoe is of the same width as the tread and the protecting strips preferably
terminate at a short distance from the edges of the shoe, so that they are
completely enclosed therein and prevented from rusting. The shoe may be
formed by laying the protecting plates between two endless strips of rubber and
then vulcanizing the strips together, forming a single endless band in which
the plates are embedded. The endless fat shoe is cemented to the tread in
the deflated condition of the tyre, as shown in Figure 3, in which condition of the
parts the series the annular recess or groove in the peripheral face of
the tyre. Upon inflating the tyre the thin depressed face portion of the
tyre forming the bottom of the recess rises until it becomes flush with the
thickened elge portions and beans spugly against the inner side of the shoe.
As the ination of the tyre does not drive this central portion of the peripheral
face outward beyond the position in which it forms with the marginal portions,
a flat face, in other words, does not crowd or bulge the peripheral face of the
tyre, there is no tendency developed to lift or force the shoe from the faces of
the marginal portions of the tyre. The shoe therefore remains securely con-
nected with the tyre, whether the latter be inflated or deflated, although the shoe
expands slightly with the tyre upon inflating the latter.
The shoe is complete in itself, and can be removed from the tyre when worn
out and replaced by a new one.
In order to prevent the side walls of the tyre from bulging beyond the elges
of the tread or armour and thereby avoid puncturing of the same, they are
arranged to converge toward the seating side of the tyre, as shown. Owing to
this arrangement of the side walls and the thickening of the real corners, when
the tyre is inflated, the non-expausible corners restram the
of the
.

page_text: walls beyond the longitudinal edges of the tread, and allow only those portions
thereof to expand which are comparatively remote from the tread, as shown
in Figure 2, thus preventing the same from being reached by objects liable to
puncture the tyre.
Our improvements are applicable to double tube tyres, comprising an inner air
tube and an enclosing cover or sheath, as well as to single tube tyres, such a
construction being shown in Figure 5. In this case, the tread of the sheath His
provided with the flat marginal portions b' and the central depressed portion c¹ and
its side walls converge toward the seating side of the tyre, while the air tube I
may be made cylindrical, in the usual manner.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. A pneumatic tyre having its tread composed of thickened marginal portions
having flat faces and an intermediate thin face portion which is depressed below
the faces of the marginal portions, forming an annular depression or groove in the
face of the tyre when deflated, which thin central portion is raised to the level of
the marginal faces upon inflating the tyre, forming therewith a practically flat face,
substantially as set forth.
2. The combination with a pneumatic tyre having its tread composed of thickened
marginal portions having flat faces and an intermediate thin face portion which
is depressed below the faces of the marginal portions, forming an annular
depression or groove in the face of the tyre when deflated, of a flat shoe or
armour secured to said marginal face portions and extending over the intermediate
face portion of the tyre, substantially as set forth.
or
3. The combination with a pneumatic tyre having a flat face, of a flat shoe
armour composed of flat disconnected, hard and resilient plates arranged
transversely and flush with each other and embedded in a band of rubber,
substantially as set forth.
Dated this 29th day of October 1895.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicants.