Improvements in the Manufacture of Metal Wheels.
Year: 1898

page_text: Date of Application, 7th June, 1898-Accepted, 6th Aug., 1898
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Metal Wheels.
I, FERDINAND EUGENE CANDA, of 11, Pine Street, Borough of Manhattan, in
the City of New York and State of New York, United States of America, Manu-
facturei, do hereby declare the nature of this invention and in what manner the
same 18 to be performed to be particularly described and ascertained in and by
the following statement
-
My invention relates chiefly although not exclusively to the manufacture of metal
wheels for railway cars and locomotives, and consists in so making the wheels
that they have a hub and 1m cast from steel or other strong and tough welding
metal and separately formed spokes which are welded to either the hub or the
rim or both in such a manner that, in the latter case the wheel 18 composed prac-
tically of one homogeneous piece of metal, which is rendered free of internal stresses
by annealing
An important feature of my invention is that I am able to produce car wheels,
that are lighter, stronger and more durable than the wheels heretofore used, and
are comparatively inexpensive to manufacture according to the method I employ
for making them.
In order that my invention may be fully understood and readily called into
practice I will proceed to describe the same by aid of the accompanying drawings
in which,
Figure 1 is an elevation of a cai wheel made in accordance with my invention
Figure 2 is a diametrical section of the wheel.
Figure 3 is a diametrical section of a mould-flask and completed mould, with
the hub core and spokes therein.
Figure 4 is a plan view of the drag and mould therein, the cope having been
lifted off, thus leaving the mould open.
Figure 5 18 a detail section of a portion of the 1m and one of the spokes of
the wheel, illustrating the weld between the 11m and spoke
Figure 6 is an elevation of one of the blanks from which the spokes are formed
Figure 7 is a plan, and
Figure 8 a side elevation of the completed spoke.
I would here iemark that although only a car wheel and the mould for making
the same are illustrated in the drawings, I wish it to be understood that by the
method of manufacture herein described belt pulleys and other wheels of a similar
nature may be made
Car wheels which are generally intended to carry heavy loads, are while in
use subjected to sudden and very severe shocks at the rail joints and other similai
places on the permanent way, and are likewise subjected to severe stresses at
curves and when the brakes are applied These considerations, and the serious
consequences that are likely to attend the breaking of a car wheel while the car
is moving, make it desirable that such wheels shall be very strong and capable
of withstanding severe shocks and stresses, and that they shall be composed of some
strong tough metal or other suitable material, the strength of which and of the
wheel made from it, may be accurately known, and which is not liable to be

page_text: readily cracked or broken. Hitherto it has been possible to make such wheels
cheaply only by casting them from cast iron Cast 11on, as is well known, 18
not a strong and tough metal, but on the contrary is weak and brittle, particularly
when cast in bodies of regular section, such as cal wheels Moreover it 18
exposed to shrinkage stresses of considerable but unknown amount, which weaken
the resulting article and render it liable to crack while in use These objections,
to which cast on car wheels are subject, have in many cases led to the use of
built up car wheels, such as the well known paper car wheels. But the necessarily
greater cost of wheels made by any process other than that of casting, has pre-
vented the use of built up wheels for most purposes
Attempts to use a better material than cast on such as cast steel containing
a low percentage of carbon, have not been successful in the past, owing to the
fact that although cast steel car wheels, if free from excessive shrinkage stresses
and other internal stresses, would possess the necessary toughness and strength,
yet, as the metal solidifies at a temperature very much higher than that at which
cast iron solidifies, excessive shrinkage stresses are produced, which make the
resulting wheel brittle and render it liable to crack or break
Another necessary
defect of any steel car wheel which is composed wholly of cast steel and cast in one
piece, as cast iron wheels are cast, is that, since steel does not "chill," as does cast
iron, and since the hub must be soft enough to be bored out for the axle, the m
must be equally soft Such a wheel, if made, would be softer on the tread than the
present chilled iron wheels.
Attempts have also been made to produce cast iron car wheels having greater
strength than wheels cast in one piece, by casting the hub and rim separately, and
connecting the hub and rim by wrought iron spokes placed in the mould before
the molten metal is poured into the mould, so that the molten metal surrounds
the ends of the spokes and in cooling grasps the spokes Such wheels, however,
have not proved superior to wheels cast in one piece The molten metal about
the ends of the spokes is chilled and solidifies more rapidly than the rest of the
wheel, thus causing lack of homogeneity and the setting up of internal stresses
in the hub and rim. Moreover there is no actual union between the metal of
the spokes and the metal cast about them, since the temperature at which cast
poured" 18 too low to raise the ends of the spokes to a welding heat, and
as a result the spokes are merely held mechanically, so that crumbling of the
metal about the spokes causes the spokes to work loose
Iron 18
.6
Car wheels are also made by forming a rim from mild steel, and, while the
rim 18 heated to a very high degree, placing it in a mould and casting into the
rim a cast iron hub and connecting web It is contended that by this method of
construction a union, resembling a weld, 19 produced between the steel 11m and
the hub and web cast within it But the resulting wheel is not altogether free
from shrinkage and other internal stresses, and possesses the disadvantages of
being composed, to some extent at least, of cast iron
The
Now according to my invention a mould is made for the wheel, as if it were
to be cast entire, separate gates, risers, and vents, however, being provided for
the hub and for the rim The spokes are formed from structural or mild steel,
and are placed within the mould, in the recesses formed by the spokes of the
pattern, their ends projecting respectively into the hub and rim moulds
rim and hub are 'poured separately, the rim being poured first, and after
the metal of the rim has set and most of the shrinkage toward the centre of the
wheel has taken place, (say about ten minutes after the rim is poured, although
the time varies somewhat according to the thickness of the rim) the hub is poured.
The molten metal must be poured at a temperature high enough to overcome the
tendency of the spokes to chill the metal about their ends, and to raise the
ends of the spokes to a welding heat before complete solidification of the molten
metal about the spokes has taken place The heat, together with the great pressure
caused by the contraction of the metal about the ends of the spokes, welds the
spokes to the hub and rim, so as to make them integral therewith The wheel

page_text: is then allowed to cool and is afterward annealed at a cherry red heat to remove
internal stresses and to restore to its original condition the metal of the spokes,
which by the heat of the molten metal is rendered brittle
*
Referring now to the drawings, and first to the parts of the wheel itself, 1 is
the rim of the wheel, and 2 the hub 3, 3, are the spokes, formed of what is
known as mild" steel, in contrast with haid or tool steel, and corresponding
in most of its properties to wrought iron, though more homogeneous and of greater
strength. Wrought iron may be used for the spokes instead of mild steel, however,
if desired, and since both metals possess in substance the same qualities, and in
particular the quality of welding, they may be termed generically "welding metal."
The spokes are preferably of some section having a web and flange at right angles,
a
4 18 the flask containing the mould within which the wheel 18 cast
It is a
two-part flask such as 18 ordinarily used in casting car wheels, 4¹ being the drag
and 4 the cope The cope and drag have radial partitions 5, 5, and also have
rings 6, 6, substantially concentric with the mould when formed, the purpose
of which is to prevent the destruction of the hub mould by the movement of the
sand in the flask during the contraction of the im The rings 6, 6, prevent
the movement of the sand near the hub mould, and therefore prevent the destruc-
tion of the hub mould
The mould for the wheel is formed as if the wheel were to be cast complete,
a full pattern, having rim, hub, and spokes being used Separate gates, misers,
and vents are provided for the hub mould and for the rim mould, however, as
the hub and im are poured separately. The complete moulds are shown in
Figure 3, 7 being the mould for the rim and 8 the mould for the hub
The 1m mould 18 usually provided with two gates, 7 7³ airanged to cause the
metal to flow into the mould from the bottom, as shown in Figure 3, and in a
tangential or nearly tangential direction, as shown in Figure 4, so that when
the metal has entered the mould it will fill it rapidly and uniformly, and will
not solidify at the mouth of the gate prematurely A number of 11sers, airanged
at intervals about the 11m mould, are also provided
The hub mould is provided with a single gate 8 and it is usually permissible
to have the metal enter the mould at the top A single rise is all that is usually
required
The spokes are constructed as follows. The blanks for the spokes are formed
by cutting into proper lengths beams of mild structural steel having the desired
section, which may be one of the standard sections in which such beams are rolled.
The web of each blank is then sheared, as indicated by the dotted lines in Figure 6,
to give the spokes the proper taper If the wheel to be made 18 of the type in
which the hub 18 offset from the 11m, the spoke is then bent in dies into the shape
required to offset the hub the proper amount
The method of casting is as follows. A core 10, for forming the axle hole
in the hub, is placed within the hub mould The spokes 3, 3, the ends of which
have been protected by glazing them over with a suitable flux, such as that made
by borax or boracic acid, are placed within the recesses formed for them in the
mould, their ends projecting into the hub and rim moulds in the manner shown
in Figures 3 and 4. The cope is then put in place, and the mould is ready for
pouring
The im mould is poured first, so as to allow the rim to contract toward the
centre without setting up shrinkage stresses, and after the rim has set and most
of its shunkage toward the centre has taken place, the hub mould 18 poured
Usually the hub is poured about ten minutes after the rim is poured During
the contraction of the rim, the rings 6, 6, of the cope and drag protect the hub
mould from being crushed in or shattered by the movement of the sand inside
the rim
The metal for the hub and rim is poured at a temperature so lugh, that before
it has completely solidified about the ends of the spokes, it has raised the ends

page_text: of the spokes to a welding heat Because of the high temperature, both of the
metal in the hub and rim moulds, and of the ends of the spokes, and because of
the pressure caused by the contraction of the metal about the ends of the spokes,
the spokes are welded into the hub and rim, becoming in fact integral therewith,
so that when completed the wheel is one piece of metal throughout This I have
demonstrated by sectioning a wheel so made, at the point or union of the spoke
and rim
By elching the metal surface, at this point, I have found that the etched
surface shows the blending of the metals between the metal of the spoke and the
metal of the rim, which is characteristic of a true weld, without the sharp dividing
line, somewhat similar to a fine crack, which would be observed were the union
between the spoke and rim merely a mechanical union
If desired, the ends of the spokes may be provided with locking holes 9, such
as are shown in Figures 3 and 4, into which the molten metal of the hub and rim
will flow, welding to the sides of these holes, and also holding the spoke in place
mechanically as well as by the weld. But I do not limut myself to the use of
these locking holes, and for this reason, I have not illustrated them in Figure 2,
or in Figures 6, 7 and 8
In the sectional view of the wheel. Figure 2, in order to show the composite
construction of the wheel, I have shown sharp dividing lines separating the metal
of the spokes from that of the 1m and hub As already stated, however, there
18 no such sharp dividing line. and the appearance of the surfaces when sectioned
and etched is more truthfully represented in Figure 5, the only thing to distinguish
the cast metal from the metal of the spokes being the slightly different color of
the cast metal
The heat of the molten metal makes the spokes brittle To restore them to
their former tough condition, as well as to remove internal stresses that may exist
within the m and hub, the wheel, after it is cold, 18 next annealed It is first
necessary to permit the wheel to become cold When cold, the entire wheel 18
heated in a suitable annealing furnace to a cherry red, and allowed to cool verv
slowly, as in ordinary annealing operations After annealing, the metal of the
spokes has practically the same properties as before the casting, and the metal
of the 1m and hub is tough and strong and has all the properties of the best cast
steel Too low heating during annealing will not produce this result and too
high heating will injuriously affect the properties of the metal.
As shown in the diawings, the spokes do not project entnely through the rim
to the outer surface or tread thereof, but project only part way through the 11m
This is necessary, in order that there shall be no soft spots in the wearing surface
of the m
The metal of the um 18 naturally somewhat harder than the metal
of the spokes, and did the ends of the spokes project through to the tread, flat
spots would soon form at the ends of the spokes which would make it necessary
to throw the wheel aside
I am aware that it has been proposed to make car wheels by casting rims and
hubs upon spokes previously prepared and placed in the mould But the object
of my invention 18 not simply to cast steel hubs and 11ms upon spokes, but 18 to
weld the spokes to the rim, or the hub or to both, so that the connection shall be
integral, and as has been already stated, this can only be done when the molten
metal is poured at a temperature enough higher than that actually required to
maintain fluidity until the mould is full, to heat the spokes to a welding heat
and overcome the tendency of the spokes to chill the metal about their ends
believe the welding of the spokes into the rim and hub by the heat of the molten
metal, and the further annealing of the wheel, to be steps which are entirely new
in the making of wheels
In order that the hub may be bored casrty for the reception of the axle, I prefer
to cast it from steel having a low percentage of carbon It is desirable, however,
that the 1m shall be quite hard, in order that it may be able to withstand the 5
action of the brake shoes without excessive wear, and may not develop flat spots
when, as sometimes happens, the biakes are applied so strongly as
cause the

page_text: wheels to slide over the track, and in order that the tread may not be injured in
passing over rail joints, frogs, switches and the like. For the rim I prefer to
use steel, low in phosphorus and sulphur and having 75 to 110 per cent. or
more of carbon, and the addition of some chromium to the steel 18 of advantage,
as it increases both the hardness and the toughness of the metal
I find from tests of these wheels that they wear out much more slowly than do
the best chilled cast 11on wheels, that they do not develop flat spots on soft spots
in the tread, nor do they break in service, and that when tested, they show very
much greater strength than the best cast iron wheels
By the term tough welding metal employed in the following claims I mean
metals such as steel and wrought iron which are strong and tough and possess
the property of welding under suitable conditions of heat and pressure. I do not
mean by this term to include cast on, which is not strong and tough, but is
always likely to develop flaws and weakness, and which does not possess the true
property of welding, but is capable of being united to other bodies of metal, if
at all, only by the piactical surface fusion thereof
When a wheel of great durability, but not necessarily of the greatest possible
strength, 18 desired, as for instance when the wheel is to be used under light and
comparatively slowly-moving cars, the hub of the wheel may be made of cast iron,
the im, however, being made of steel In the wheel so made the spokes will
be welded into the rim, and will be held mechanically in the hub by the shrinkage
of the cast iron when solidifying about the ends of the spokes. Such a wheel I
egard as within my invention.
Having now particularly described and ascertained the nature of my said inven-
tion and in what mannei the same is to be performed, I declare that what I
claim is.-
1
1 The herein described method of manufacturing a metal wheel which consists
essentially in causing a series of separately formed spokes contained in a suitable
mould, to be welded to the rim or the hub or to both by the combined action of
the high temperature of the molten metal poured into the mould to form the said
rim and hub and the pressure resulting from the solidification and shrinkage of
such molten metal, the wheel so made being subsequently annealed for the purpose
specified
2 A wheel having a cast-steel hub and 1m connected by a series of spokes
composed of tough welding metal, the said spokes being formed separately from
the hub and rim, and welded to one or both of the latter substantially as described
and for the purpose specified
3. A metal wheel manufactured substantially as herein before described with
reference to the accompanying drawings for the purpose specified
Dated this 7th day of June 1898
HASELTINE, LAKE & Co,
45, Southampton Buildings, London, WC,
Agents for the Applicant