in metal tyres and in elastic tyres for wheels
Year: 1899

page_text: I, HOWARD MALCOLM DU BOIS, of Ashbourne, Montgomery County, in the State
of Pennsylvania, United States of America, Manufacturer, 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:-
The invention relates to new and useful improvements in metal tyres and in
elastic tyres for wheels.
The object of this invention is to construct tyres for wheels, so proportioned
as to accord with the mechanical principles of the vehicle and thus avoid un-
necessary strain upon the wheel, diminish the resistance to the motion of the
wheel and reduce the wear and strain upon the tyre while in action.
The accompanying drawings illustrate the invention:
Figure I is an edge view of the wheel with the tyre in section.
Figure II is a cross section of the wooden felloe, the grooved metal tyre and
the elastic tyre.
Figure III is a top edge view of two wheels of a vehicle.
Figure IV is a front edge view of two wheels of a vehicle.
To fully understand the scope of this invention, a knowledge of the mechanical
principles observed in the construction of vehicles is necessary. Vehicles are
so constructed that the friction of the wheel is reduced to a minimum, and also,
so that the wheels and tyres may be strong to resist the opposing forces. To
accomplish this the axles are set with what is called in the art,
gather," that
is to say, the axle of the wheels are inclined slightly forward from the collar
to the point, so that the distance between the wheels is less in front than back.
(See Figure III). The wheel when in motion is thus caused to press against the
collar of the axle the draft is brought to a fixed point and the motion of the
swing." To
wheel made steady. The axles are also set with what is called "
accomplish this the spokes are inclined inwardly from the felloe to the hub so
that the wheels from an outer point of view are concave in form, or dished.
The axles are inclined downward to an extent equalling the dish of the wheel
(see Figure IV). The "plumb spoke." is thus secured, that is the spoke which
supports the load and is directly in the line of weight, stands plumb and the
weight is thown upon the centre of the box, which is secured in the hub of the
revolving wheel.
The elastic tires heretofore made have been so formed that the apex of the

page_text: tire which first comes in contact with the pavement is at a point perpendicular
to the centre of the channel or tire.
When such an elastic tire is placed on the wheels of a vehicle constructed in
the way above mentioned, so that the wheels will have sufficient "swing" to
secure a plumb spoke, and sufficient "gather" to reduce the draft to a minimum,
the weight of the load in the vehicle flattens the rubber at the point of contact
and as the wheel revolves forward the elastic material is forced inward over the
edge of the channel, thus changing the line of weight from the centre of the
box of the wheel inwardly toward the collar of the axle.
When a vehicle turns a corner, the wheels which describe the outer circle
are whirled about with great centrifugal force, the weight of the load shifts
outward and the elastic tire which clings to the pavement is pushed inwardly;
while the wheels which describe the inner circle are so acted upon by the
momentum and the shifting of the centre of gravity of the vehicle, that the tires
are forced outward. When the clastic material flows outward over the flange,
the force of the lever, the flange being the fulcrum, is exerted against the dish
of the wheel in a direction opposite to that which the wheel is made to resist,
thus causing the spokes to weaken, and at the same time causing an extraordinary
strain upon the inner retaining wire.
To overcome these difficulties I have constructed a tire which is supported,
strengthened and shaped as follows: About the wheel is fastened a grooved metal
tire A with flanges extending at any angle desirable. The edges of the flanges
are round to prevent abrasion of the rubber. The inner flange B is longer than
the outer flange C. Into the groove of the metal tire the elastic tire D is fitted.
It is held in place within the groove by two wires G and F. More wires may
be used if desired. The wires are drawn through holes extending throughout
the length of the tire. The outer wire G is preferably equi-distant from the
base and flange of the metal tire; whereas the inner wire F is more distant from
the base of the metal tire than the wire G. The wires are secured and tightened
by welding, twisting or other convenient method. The elastic tire D is convex
from its apex to the point of contact with the long inner flange while it is
slightly S shaped from the apex to the point of contact with the outer flange C.
The apex of the tire is at the point H, which is inward from the line X erected
perpendicular to the centre of the metal tire A. Thus the greater bulk of the
tire is inward from the perpendicular line X.
The tire must withstand three forces-First: The upward pushing force against
the line of weight. Second: The inward pushing sidewise force caused by the
'gather" of the wheels. Third: The outward pushing sidewise force caused
when the inner wheels of the vehicle turn a corner.
66
The inward force exerted because of the " gather" of the wheel is resisted
by the long inner flange B of the metal channel, which prevents the rubber from
flowing inward over the flange and which also relieves the strain upon the outer
wire G. The wire G when unassisted tends to cut through the elastic material.
The outward force is so opposed by the inner retaining band F which is placed
higher in the body of the rubber than the other retaining wire, that it cannot
be pushed beyond the line of weight I. This arrangement of the retaining
wire F in a different plane from the metal tire than the wire G, increases the
strength of the rubber in cross section and permits freer movement of the mole-
cules of the elastic material.
When the metal tire is placed about the wheel, it is expanded by heat. Because
of the greater weight of the inner edge of the metal tire, when the metal is
cooled, a greater pressure is exerted upon the inner edge of the wooden felloe
of the wheel than upon the outer edge. This restrains the wheel from excessive
dish.
The tire thus constructed and protected is confined within the metal flanges
and never forced between the flanges and the pavement. Thus unnecessary
dragging of the elastic material and resistance to the motion is prevented.

page_text: "
Such a tire is in accord with the principles of "plumb spoke" and "gather
which causes the force exerted against the inner mictal flange to be opposed by
the plumb spoke of the wheel.
Furthermore it prevents the line of weight from moving from the centre of
the box of the wheel, thus avoiding unnecessary strain and friction.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. An elastic tire for a vehicle fitted into a grooved or flanged metal tire in
which the inner flange is longer than the outer flange, so shaped that the part
resting upon the road-bed shall have its centre inward from the centre of the
metal tire and kept in place by means of wires which are tightened about the
wheel through holes in the elastic material, each hole being in a different hori-
zontal plane from the base of the metal tire, substantially as hereinbefore
described.
II. An elastic tire so shaped that the greater bulk of the elastic material is
inward from a line erected perpendicular to the centre of the plane of the metal
channel upon which the tire rests, substantially as herein before described.
III. A vehicle wheel with a flanged metal tire, the flange inward toward the
vehicle being longer than the outer flange so that a tire, shaped with the greater
bulk of the elastic material inward from a plane perpendicular to the central
point of the metal tire, and when fastened in the metal channel, will bear against
the longer flange, substantially as shown and for the purposes specified.
IV. A vehicle wheel with a flanged metal tire in which the flange inward
toward the vehicle is heavier than the outer flange so that a rubber tire shaped
with the greater bulk of the rubber inward from a plane perpendicular to the
centre of the metal tire, will bear against the heavier flange substantially as
shown, for the purposes specified.
V. An elastic tire having holes throughout its length through which retaining
wires extend, each in a different horizontal plane, substantially as shown for the
purposes specified.
VI. A vehicle wheel with a flanged metal tire, in which the flange inward
toward the vehicle is longer and heavier than the outer flange, into which metal
tire is fitted an elastic tire, shaped with the greater bulk of the elastic material
inward from a plane perpendicular to the centre of the metal tire, so that the
elastic material will bear against the long heavy flange, the said elastic material
being held in place by two or more wires extending through the same about the
wheel, substantially as described and for the purposes specified.
VII. A vehicle wheel with a flanged metal tire, in which the flange inward
toward the vehicle is longer and heavier than the outer flange, each flange
extending at any desirable angle from the metal tire, thus making a groove into
which is fitted an elastic tire shaped with the greater bulk of the elastic material
inward from a plane perpendicular to the centre of the metal tire, so that the
elastic material will bear against the long heavy flange, the said elastic material
being held in place by two or more wires extending through the same about the
wheel, substantially as described and for the purposes specified.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.