the like, with Chilled or Hard Spots in the Wheel-engaging Surface.
Year: 1885

page_text: the like, with Chilled or Hard Spots in the Wheel-engaging
Surface.
I, WILLIAM PHILLIPS THOMPSON, Fel. Inst. P.A. of the Agency for Foreign
Patent Solicitors, 6 Lord Street, Liverpool, in the County of Lancaster, and
823 High Holborn, in the County of Middlesex, Civil Engineer, do hereby declare
the nature of this invention (a communication from abroad by Charles Frederick
Wohlfarth, of Norwich in the State of Connecticut, United States of America,
Mechanic) and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:—
The improvements relate to that class of Brake Shoes in which certain portions of
the surface which is to engage the car wheel, when in use, are chilled or hardened
to prevent the rapid and undue wearing of said shoe; the softer surrounding
portions being left free to perform their customary functions.
Briefly described the invention consists in placing in the mold before pouring, a
core of zinc or other similar, easily fusible metal, which, as the molten iron flows
in, is quickly melted and united with said iron producing an amalgam which when
cool forms a hard or so called "chilled" spot in the face of the shoe.
Referring to the annexed drawings
Figure 1 shows side and face views of a finished brake shoe with "chills;"
Figure 2 the core used in producing chilled spots as more fully referred to
hereinafter, and
Figure 3 illustrates the preferred method of molding and casting said shoes.
a represents the finished brake shoe having properly located in its curved face
chilled spots b, each surrounded by the softer iron. c represents the block or core
of zinc which is used to produce said chilled spots, as above referred to.
These chilled spots may be of any desired number, and may be disposed through-
out the face of the shoe as desired but it is preferred in practice to so locate said
spots that each shall be completely surrounded with the softer metal, as shown in
Figure 1.

page_text: In Figure 3 is illustrated top and sectional views of the matrix or mold as it
appears when ready for pouring, the cores c being shown in position.
Should there be any inclination on the part of the zinc cores to move in the
mold as the iron surrounds them they may be slightly imbedded in the sand or
may be secured by baked sand dowels extending downward into the sand but,
thus far, in experiments made, no inconvenience from such displacement has been
experienced.
With a construction such as described the life-time of the shoe is greatly
extended, as is well known to those familiar with this class of devices, and as
the hard parts are integral with the softer portion they cannot possibly become
loosened in their seats..
In this respect shoes so formed are superior to those having chilled portions
dove-tailed or otherwise fastened into the shoe proper.
In pouring the molten iron it will be found preferable to introduce it at opposite
sides of each core (see Figure 3) so that the fusion of the core, and the amalgamating
of said core with the iron shall proceed simultaneously on all sides. The volume
and weight of the surrounding iron also acts to prevent the displacement of the
cores.
In Figure 1 is shown in rectangular outline the position of the cores as they are
first set in the mold, and is also indicated by irregular lines the approximate
outline of the chilled portions after the amalgamation of the core and iron.
Although the cores have been described as blocks of zinc, pieces of glass placed
in the mold will also produce chilled spots but zinc is preferred as it melts at a
comparatively low temperature.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is
The method herein described for producing chilled or hard spots in the wheel
engaging surface of car brake shoes; consisting essentially of first, preparing the
matrix or mold in the customary manner, second, of placing at desired points in
Baid mold one or more cores of zinc or other easily fusible material, and third, of
so pouring in the molten iron that it acts to fuse said core or cores to produce
chilled spots" as specified.
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