Year: 1898

page_text: Date of Application, 8th June, 1898-Accepted, 28th Jan., 1899
A communication by WILLIAM MARVIN HOFFMAN, of 347, Baldwin Avenue,
Detroit, in the State of Michigan, United States of America.
I, WILLIAM PIIILLIPS THOMPSON, FCS, MIME, of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester,
both in the County of Lancaster, 118, New Street, Birmingham, in the County
of Warwick, and 322, High Holborn, in the County of Middlesex, Civil Engineer,
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 follow-
ing statement.
This invention relates to grinding blocks for trueing cat wheels, and has for
its object an improved form of shoe adapted to be used in connection with a
system of levers and rods, or adapted to be used in the ordinary brake head of
the brake system employed on ears It consists of a casting shaped somewhat
like an ordinary brake shoe, but provided on that side which is intended to lie
next adjacent to the wheel with a number of pockets, or openings, or cavities,
into some of which is forced an abrading substance, and the exposed surfaces of
the abrading substance is finished to a shape which in one direction is arched
and in the other direction corresponds to the face of the wheel, in the form of
which it is desired the wheel to remain
The diawing shows the grinding shoe
A indicates a shoe arched on its outer or back contour to correspond to the
brake head with which it is to be employed, and provided with a lug B by means
of which it may be attached to the ordinar brake head in the same way that a
brake shoe 18 attached This side or face of the shoe may be varied in shape to
correspond with the special form of biake head with which it is to be employed
The inner face, or that face which 18 intended to be used for grinding 18 arched
between the ends a and b, and is provided with several cavities, and of these
cavities a number as c care filled with abiading material, packed, pressed or
cemented therein, and with the inner face of the abiading material shaped so
that a line across the shoe from d to d' will conform to a line across the wheel
As shown in the drawing, this line would conform to a wheel that is adapted to
run in what is known as the grooved rail One or more of the pockets ee¹ are
left vacant or unfilled with abrading material, and are preferably provided with
holes through. which dust or dirt that may gather in the pockets ee¹ can
escape freely
By using a number of pockets filled with abrading material a number of sharp
or scraping edges is produced where the wheel engages the edge of the abiading
material, and this not only serves to clean the wheel from any dirt that may have
gathered upon it, but serves to gund it more rapidly than "would a block filled
with a single muss of ginding material
Inasmuch as the almading material is harder than the shell of the shoe and will

page_text: wear longer than the shell of the shoe which is generally of cast iron, and
generally soft when compared either with the abrading material or the wheel
which 18 chilled, there is always a sharp scraping edge to the abrading material,
and to the cross walls of the sections which contain it
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.―
1 An abrading shoe adapted to be used for trueing up car wheels, having in
combination & metallic shell and a filling of abrading material, and provided with
clearance holes, substantially as described.
2. In an abrading shoe adapted to be used for trueing up car wheels, the com-
bination of a shell provided with a plurality of cavities adapted to be filled with
abrading material, blocks of abrading material-set therein, cavities intermediate
the blocks provided with openings whereby accumulated material may be dis-
charged, substantially as described
3. In an abrading shoe adapted to be used for trueing up car wheels, the
combination of a shell, abrading material set therein, and clearance holes between
adjacent portions of the abrading material, substantially as described.
THRO
5430 2534
W. P THOMPSON & Co,
Agents.
W. P THOMPSON & Co,
Agents.