improvements in and relating to Cushion Tires for Bicycles and other Vehicles.
Year: 1892

page_text: Date of Application, 15th Mar., 1892-Accepted, 16th Apr., 1892
COMPLETE SPECIFICATION.
improvements in and relating to Cushion Tires for Bicycles and
other Vehicles.
1, WILLIAM CRANCH MINTIRE, a citizen of the United States of America,
residing at No. 1521 Rhode Island Avenue, in the City of Washington, District
of Columbia, United States of America, Solicitor of Patents, 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 to certain new and useful improvements in cushion tires
for bicycles, and it has for its object not only to provide a substantial and
effective air cushion within the body of the rubber of which the tire is composed,.
but also to avoid the cutting action which usually takes place.
In tires of the class to which my invention relates, it has been most cominon
to form them with a cylindrical hollow air space, but with this form of con-
struction, experience has demonstrated that the constant compression or partial
flattening of the tire causes the rubber on each side of the central air space to
form an acute angle, and that this constant action tends to cut or split the rubber
in a diametric line, thus soon depriving it of its original and desired elasticity
and in a short time rendering it useless.
It has been suggested to overcome the disadvantage just described by forming
tires with two ribs or reinforcements, one on each side of the inner surface, but,
while this construction may add increased strength at the lines where they exist,
the cushioning effect of the interior air space is correspondingly decreased.
My invention is designed to overcome the disadvantages of both of the described
constructions, and at the same time secure the desirable effect of the air cushion in
its greatest extent; and with these ends in view my invention consists of a tire
having a central air space communicating with air spaces on cach side of the said
central space, the relation and form of the three air spaces being such that con-
tinuous heels or projections are formed each side of the central space, which heels
shall come in contact when the tire is compressed, and serve not only as elastic
supports, but at the same time constitute walls or partitions between the central
space and the two outside air spaces, thus, as it were, dividing the original single.
air space into three parallel air spaces. Not only is this result secured, but by
reason of the supporting contact of the heels or projections, the outside portion of
the circumference of the two lateral air spaces is protected from the cutting action
which occurs in tires having a single central air space, for the reason that such
outside lines of the lateral air-spaces always maintain a curved direction and never
assume the acute angle form occurring in the single circular air cushion.
My invention will be readily understood by reference to the accompanying
drawing, in which―
Figure 1 represents a cross section of a rubber tire:
Figure 2 a similar view showing the tire partially compressed; and
Figure 3 a similar view showing the tire compressed to the full extent which
occurs in use.
Similar letters denote like parts in the several views.
A, represents the tire which is formed of rubber and properly vulcanized as is
well understood in the manufacture of such goods. B, represents 'a central
cylindrical air space extending throughout the whole length of the tire, and
C, C, represents contiguous parallel auxiliary air spaces communicating laterally
throughout their whole extent with the central air space, B. I have shown the
three air spaces as cylindrical in form and with the two outside or parallel
spaces, C, C, of just half the diameter of the central air space, B, the centers.

page_text: of the spaces, C, C, bearing such relation to the center of space, B, that the
circumference of the latter is intersected by the circumference of each of the
spaces, C, C, thus forming continuous heels or projections, e, e.
It will be observed that when the compression of the tire takes place the
heels, e, e, approach each other, as seen at Figure 2, and finally come in contact
with and support each other and form as it were walls or partitions between the
outside spaces, C, C, and the central space, B, these walls or partitions constituting
parallel elastic supports in the direction indicated by dotted lines in Figure 3, and
it will also be seen that when this condition and relation of the air spaces is
assumed, that the inside surface of the spaces, C, C, at the points furthest from the
center of the tire maintain a curved direction, and thus the cutting action referred
to is avoided.
While I prefer to make the air spaces cylindrical in cross section, it will be
understood that I do not wish to confine myself to exact lines of contour, nor do
I wish to be understood as limiting myself to the exact proportions named, as
variations in these particulars may be made without departing from the spirit of
my invention so long as there exists the parallel and contiguous air spaces with
heels or projections produced by the intersection of the boundaries of the three
air spaces.
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 :-
1. A rubber tire for bicycles and other vehicles formed with a central air space
bounded on each side by parallel and intersecting air spaces, substantially as
hereinbefore set forth.
2. A rubber tire for bicycles and other vehicles having a central air space, B,
two parallel and intersecting air spaces, C, C, and continuous heels or pro-
jections, e, e, substantially as and for the purposes set forth.
Dated this 15th day of March 1909
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.