Improvements in and relating to Vehicle Wheels, and more particularly to Driving Wheels for Locomotives.
Year: 1897

page_text: Date of Application, 9th Mar., 1897-Accepted, 22nd May, 1897
COMPLETE SPECIFICATION.
Improvements in and relating to Vehicle Wheels, and more
particularly to Driving Wheels for Locomotives.
1, PHILIP ZEPHANIAH DAVIS, a citizen of the United States of America, residing
at Lometa, in the County of Lampasas and State of Texas, United States of America,
Machinist, 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, generally, to vehicle wheels, and particularly to driving
wheels for locomotives, and it has for its object to provide an approximately perfect
balanced driving wheel and thereby materially decrease the internal disturbances to
the mechanism of the locomotive due to the present methods of counterbalancing in
the driving wheel the reciprocating and revolving parts thereof.
This object I accomplish by equalizing the vertical effect of the normal forces
exerted by the crank pin and boss and counterweights as they move or travel through
the path of a prolate or inflected cycloid, thus neutralizing their effect and reducing
the hammer blow or wave force on the rail to zero.
To this end my invention, generally stated, consists in the arrangement and
distribution of the weight of the crank pin and counterweights and all other weights
placed on the wheel in such manner that their vertical and horizontal forces will
exactly balance each other at all times during the revolution of the wheel and thus
entirely obviate the hammer blow or wave force given the rail at the point of
instantaneous contact of wheel and rail which is the center of rotation of the wheel
when the wheel is moving on the rail.
The object of my invention may be accomplished by several arrangements, as will
be hereinafter described, and generally stated, by the arrangement of one or more
series of weights in a circle or circles within the circumference of the wheel and
coincident with the center thereof, the weights of each circle, whether one or more
than one circle of weights is used, being arranged at like angular distances apart
relative each other, as will be more fully described hereinafter.
In the accompanying drawings forming a part of this specification-
Figure 1 is a side elevation of a driving wheel constructed according to my
invention;
Figure 2 a diagrammatic view illustrating the inflection points in the path of
movement of the weights;
Figure 3 a diagrammatic view illustrating the path travelled by the weights while
the wheel is moving on the rail, such path being a prolate cycloid;
Figure 4, a diagrammatic view showing the relation of a prolate cycloid to the
instantaneous center of rotation and the manner in which the normal forces are
developed;
Figure 5 a side elevation of a driving wheel showing a modified form of my
invention; and
Figure 6 a similar view, showing another modification of the invention.
Similar letters refer to similar parts throughout the several views.
Referring to the drawings, and more particularly to Figures 1, 2 and 3, A represents
a driving wheel, and B a series of weights arranged in a line on the balancing circle a,
around the wheel near its periphery and coinciding with the axis thereof, said weights
Price RdI

page_text: being spaced the same distance apart and preferably cast with the wheel, although
they may be cast separately and secured thereto in any desired or convenient manner.
(represents a serios of weights arranged in the crank circle b on the wheel
coincident with the axis thereof and adjacent its hub, said weights also being cast with
or otherwise secured to the wheel as found most convenient, and D represents the boss
for the crank pin E, said boss and pin being equal to and forming one of the weights
of the series of weights C, and said series of weights being arranged at equal distances
apart and at points intermediate the weights B.
In the modification shown in Figure 5, F represents a ring of suitable material
arranged on the wheel and concentric therewith and adjacent its periphery; and
Ga similar ring of less diameter, arranged within the space between ring F and
the center of the wheel and also concentric with the wheel. These rings may be
made up of a series of segments, as indicated by dotted line, c, if desired, and secured
to the wheel in any preferred manner, or they may be cast in one piece and secured
thereto, or they may be cast with the wheel; but I prefer the segmental form as the
most convenient, and as I am enabled to better balance or equalize the weight of the
ring as a whole when thus made up. In order to provide for the attachment of
the crank pin, a boss, H, is formed in the ring when cast with the wheel or when cast
in one piece, but I may cast it with the wheel and let the ends of the rings abut, or fit
thereagainst if desired.
In the modification shown in Figure 6, L, represents a series of weights (of which
one, M, represents the boss for the crank pin, N, the combined weight of which equals
and takes the place of one of the weights L) arranged in the line of a circle, d, around
the wheel, raf tile being concentric with the axis of the wheel, and located, in this
instance, midway the circumference and the axis of the wheel, and said weights being
arranged at equal angular distances apart relative the circumference of the wheel and
preferably cast therewith, although they may be secured thereto in any desired
manner.
A prolate cycloid or right trochoid, is the curve traced out by a point within the
circumference of a circle which rolls, without sliding, on a fixed straight line in the
same plane. Thus, as in Figure 4, the path travelled by the weight B is located
within the circle A¹, A' A³ A A. When the center O of the wheel has an advance
to the point O¹ the circle has an angular advance to the point A³, and the point or
weight B reaches the point B¹, and when the angular advance of the circle equals the
point As, the point or weight B reaches the point B. The point or weight B travels
in a path which is always at right angles to the line which passes through point B and
the instantaneous center of rotation, and its velocity is in the ratio of the distance
that point B is from the instantaneous center of rotation (or point of contact with
rail), to the radius of the circumference of the circle. The normal forces are always
exerted at right angles to the tangent at the point in question. Hence, the normal
force always passes through the instantaneous center of rotation, and at inflection
points P, the radius of curvature being infinity, there is no normal force; but on
passing beyond the inflection point the force is exerted in the opposite direction,
namely, at A, B, the force is exerted in the direction from B to A. At point P
there is no normal force. At B' the force is in the direction from B to A*; at B³ in
the direction from B to A³, all as indicated by arrows.
In Figure 2 the inflection points of the weights on the crank circle are marked R,
and the inflection points of the weights on the balancing circle are marked P.
In Figure 3 the paths travelled by the weights B and C in prolate cycloid are
indicated by the lines e and f, respectively, as the wheel moves on the rail.
Referring to Figure 1, as an illustration of the application of my preferred form
of invention to a wheel of a given size, take, for instance, a wheel sixty (60) inches
in diameter, with crank circle twelve (12) inches radius, and balancing circle twenty
(20) inches radius, I apply on crank circle three (3) weights C of equal size which
with the boss D and pin E, which form another weight, are arranged at a distance of
ninety (90) degrees apart around the circle, and on the balancing circle I arrange a
series of tour (4) weights B, of equal weight, at a distance apart of ninety (90) degrees

page_text: around the circle. This arrangement of the two series of weights spaces them
forty-five (45) degrees apart relative the circumference of the wheel.
In Figure 6 is illustrated the application of another form of my invention,
consisting of a single series of weights, to a wheel forty-eight (48) inches in
diameter, with crank circle twelve (12) inches radius, in which two weights Lof
equal size, which with the boss M. and pin N, which together form another weight,
are arranged at a distance of one hundred and twenty (120) degrees apart around
the circle.
For wheels of other diameters or different radii for crank or balancing circles, or
when the above ratios of crank and balancing circles and the circle or circumference
of the wheel vary relative each other, the weight of the weights is varied, but they
are always spaced either forty-five (45) degrees apart or one hundred and twenty
(120) degrees apart relative the circumference of the wheel.
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 wheel having a series of weights arranged at equal distances apart in a circle
adjacent to and coinciding with the axis of the wheel, and a series of weights
arranged at equal distances apart on a circle adjacent the periphery of and coinciding
with the axis of the wheel, the weights of both circles being at equal angular distances
apart relative the circumference of the wheel, substantially as described.
2. A wheel having a series of weights arranged in a circle and a weight arranged
on the line of a circle within the series of weights, all of said weights being an equal
angular distance apart relative the center of the wheel, substantially as described.
3. A wheel for a locomotive having a series of weights arranged in a circle thereon
and a series of weights arrange: on the line of a circle within the outer series of
weights, the weights of each circle being an equal angular distance apart relative
the center of the wheel, substantially as described.
4. A driving wheel for locomotives having a balancing weight of annular form
between its circumference and center and concentric therewith, substantially as
described.
5. A driving wheel for locomotives having a balancing weight of annular form
within its circumference and adjacent thereto and concentric therewith, and a similar
weight within the circle of the first named weight and adjacent the axis of and
concentric with said wheel, substantially as described.
6. A driving wheel for locomotives having a balancing weight within its circum-
ference and concentric therewith, said weight consisting of a series of segments
arranged end to end to form a ring, substantially as described.
7. A locomotive drive wheel having a series of weights arranged on the line of a
circle within the circumference of the wheel at equal angular distances apart relative
the center of the wheel, whereby the vertical and horizontal forces generated during
the revolution of the wheel are balanced, substantially as described.
8. A locomotive drive wheel having three equal weights arranged on the line of a
circle midway the center and circumference of the wheel and at equal angular
distances apart relative the center of the wheel, whereby the vertical and horizontal
forces generated during the revolution of the wheel are balanced, substantially as
described.