Improvements in Brake Shoes.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Brake Shoes.
We, JAMES FRANCIS MORRISON, of 223, 29th Street, Chicago, Illinois, United
States, Railway Superintendent, ANDREW JACKSON ALLEN, of 6346, Ellis Avenue
Chicago, aforesaid, Workshop Foreman, and HENRY RAWSTRON, of 7127, Went-
worth Avenue, Chicago, aforesaid, Company's Accountant, do hereby declare the
nature of this invention to be as follows:-
This invention relates to improvements in brake shoes and its primary object
is to increase the grip or frictional action of the shoe.
For this purpose we employ a shell filled with an improved composition. This
composition consists of the following ingredients:
Comminuted iron,
Asphaltum and
Wahsatch rock.
These ingredients are preferably mixed together in the following manner and
in substantially the proportions given. The asphaltum is melted under say, a
temperature of 400 degrees Fahrenheit and the iron chips or iron turnings or
other comminuted iron is mixed with it, after which the Wahsatch rock reduced
We have
to a powder is thoroughly incorporated and commingled with it.
obtained the best results for general purposes by using eighteen parts of iron
to one each of asphaltum and Wahsatch rock. Wahsatch rock is a limestone
impregnated with asphalt, and it is obtainable from the mines of the Assyrian
Asphalt Company in the State of Utah, one of the United States of America.
We prefer to employ a shell made with enlarged ends that is to say consider-
ably thicker than the sides and these ends are chilled in the casting preferably
so as to be hardest at the face and gradually get softer as they are reduced by
wear. The ends and sides of the shell incline inwards so as to retain the com-
position and the composition is forced into the shell under great pressure and
preferably whilst in a heated state and in new shoes the composition may more
or less project.
2
1
1000
DRACUP & NOWELL,
Patent Agents, Bradford.

page_text: Chicago, aforesaid, Workshop Foreman, and HENRY RAWSTRON, of 7127, Went-
worth Avenue, Chicago, aforesaid, Company's Accountant, 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:-
1
This invention relates to improvements in that type of brake shoe in which a
shell is employed to hold a composition, and its primary object is to increase the
grip or frictional action of the shoe.
For this purpose we employ a shell filled with an improved composition. This
composition consists of the following ingredients:
Comminuted iron,
Asphaltum and
Wahsatch rock.
These ingredients are preferably mixed together in the following manner and
in substantially the proportions given. The asphaltum is melted under say, a
temperature of 400 degrees Fahrenheit and the iron chips or iron turnings or
other comminuted iron is mixed with it, after which the Wahsatch rock reduced
to a powder is thoroughly incorporated and commingled with it. We have
obtained the best results for general purposes by using eighteen parts of iron
to one each of asphaltum and Wahsatch rock. Wahsatch rock is a limestone
impregnated with asphalt, and it is obtainable from the mines of the Assyrian
Asphalt Company in the State of Utah, one of the United States of America.
The asphaltum acts as a binder and also imparts elasticity to the composition,
while the Wahsatch rock counteracts this elasticity and also acts to a certain
extent as a binder. The degree of elasticity and the coefficient of friction are
governed by the amount of the added Wahsatch rock.
Where materials such as those as we have specified are employed, the mass is
thoroughly coherent throughout, whereby a separation or disintegration is
impossible, and even though the heat generated by friction in the application of
the shoe to the wheel may be very great the only effect will be to make the
friction body or composition slightly more ductile, and this condition will exist
only during the presence of the excessive heat.
Our composition is such that granular particles are not formed between the
brake and the shoe, and the frictional engagement is slightly yielding, so as to
prevent the shoe from becoming rigidly clamped upon the "wheel to cause the
same to skid.
Our composition when useil in brakes applied to wheels having small holes
or imperfections as it is worn off fills such holes or depressions as may exist in
the tread of the wheels to conform to the outline of the working or frictional
surface of the brake.
To fully describe our invention, reference is made to the accompanying sheet
of drawings forming a part of this specification, in which similar letters of
reference indicate corresponding parts in each of the figures.
Figure 1, is a side view of our improved shell filled with composition.
Figure 2, is a front view of the same, and
Figure 3 is a cross section on the broken line y, z, Figure 1.
The shell is provided with eyes b, b, whereby it is mounted. The interior
walls of the shell slope from the back to the front thereof, as clearly indicated.
The composition d is forced within the shell under heavy pressure and pre-
ferably while in a hot condition. The mass is thus solidified to the required
degree and firmly embedded within the shell. By tapering the walls the dis-
lodgement of the mass is prevented.
We preferably make the ends c, c of the shell thick and chill the same during
the process of casting. The ends are preferably taper chilled, diminishing in
hardness from the place of greatest hardness at the front c of the shoe towards
the unchilled portion of the shell at the back of the shoe.
The composition in the newly manufactured shoe preferably extends beyond

page_text: the shell,
portions of
brake shoe
as
is
shown. As the body is worn down the hardest
the chilled ends are engaged by the wheel. As the
worn away the chilled ends thereof gradually be-
come softer, while the engaged area of the composition or frictional body
gradually increases, the intention being to have the resultant frictional effect
of the chilled ends of the shoe and the frictional body maintained constant by
the gradually increasing frictional area of the body and the gradually reduced
hardness of the ends of the shoe as the shoe is worn away.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is;
-
1. A composition for brake shoes consisting of comminuted iron, asphaltum and
Wahsatch rock intermixed in substantially the proportions specified.
2. The combination with the shell of a brake shoe having enlarged taper
chilled ends, the inner surfaces of the walls of the shell sloping from the back
to the front thereof of a composition contained within the shell comprising
comminuted iron, asphaltum and Wahsatch rock intermixed in substantially the
proportions specified.
3. The combination with the shell of a brake shoe, having enlarged taper
chilled ends, the inner surfaces of the walls of the shell sloping from the back
to the front thereof, of a frictional body conforming to the interior of the shell,
the frictional area of the body being enlarged as the shoe is worn away to com-
pensate for the decreasing hardness of the chilled ends of the shoe.
4. A composition for brake shoes, consisting of comminuted iron, asphaltum
and an ingredient to counteract the elasticity of the asphaltum substantially as
described.
Dated this Ofth day of June 1899
DRACUP & NOWELL,
Patent Agents, Bradford.