Improvements in Brake Shoes.
Year: 1894

page_text: Date of Application, 17th July, 1894-Accepted, 18th Aug., 1894
Improvements in Brake Shoes.
1, WILLIAM DURHAM SARGENT, corner of 59th and Wallace Streets, Chicago,
Cook County, Illinois, United States of America, Manufacturer, 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 to improvements in that class of brake shoes that are
designed to perform the function of "dressers" for the car-wheels, the purpose
being to have the brake shoe, while in the performance of its function as a brake,
subserve the additional function of dressing or wearing such portions of the car-
wheel tread and flange as are not worn by contact with the rail.
The primary object of this invention is a brake shoe that shall dress or wear the
flange and tread of the car-wheel in such manner as to maintain the same in
substantially its original contour in cross-section.
Another primary object of my invention is a material reduction in the weight of
brake shoes of this class, and a consequent substantial economy in the manufacture
thereof, without loss or detriment to the braking qualities of the shoe and with the
maximum durability, efficiency and accuracy as a dressing shoe.
These objects are attained by the devices illustrated in the accompanying
drawings, in which:
Figure 1 represents a detail section of a portion of a car wheel and rail, with a
diagrammatic illustration of the effect of wear upon the wheel.
Figure 2 represents a rear elevation of a brake shoe embodying my invention.
Figure 3 represents a central longitudinal section on the line 3-3 of Figure 2;
and
'
Figure 4 represents a transverse vertical section on the line 4-4 of Figure 2.
Similar letters of reference indicate the same parts in the several figures of the
drawing.
Referring now to Figure 1 in which is shown a substantially correct representa-
tion of the head of a standard rail and the tread of a standard car-wheel, the full
lines represent the outline of the parts as they appear when first entering service.
The curved dotted line l indicates the wear of the wheel tread and flange with.
approximate or theoretical correctness in the case of a wheel to which a dressing
brake shoe is not applied.
The area of maximum wear is from the dotted line y to the dotted line y'
immediately over the head of the rail, and the areas of proportional wear are
between the dotted lines y and x and y and x respectively, the points of minimum
wear being at and respectively on the flange and tread of the wheel, the
degree of proportional wear gradually diminishing from the area of maximum
wear to the point of minimum wear. The office of the dressing brake shoe is to
dress or wear away the portions of the wheel tread and flange that are not worn or
are partially worn by contact with the rail, and the most perfect and satisfactory
results to be obtained by the use of such a shoe is such a proportional wear of the
wheel tread and flange as will maintain the periphery of the wheel in substantially
the same contour throughout its life, so as to avoid the necessity for removing the
wheels from the car truck and taking them to the shops to be turned and tried up
by a lathe, which would otherwise be necessary.
The brake shoe illustrated in Figures 2, 3 and 4, performs this office with
accuracy and certainty, the wearing surface thereof opposed to the car-wheel being

page_text: accurately proportioned to wear with different degrees of effect upon the different
portions of the car-wheel and tread, so as to produce greater or less wear thereon,
according to the wear to which the parts are subjected by contact with the rail,
thus serving to maintain the contour of the tread and flange at all times substantially
the same as that shown by the full line in Figure 1.
This brake shoe is of the ordinary or any desired dimensions and is of the type
known as the flange brake shoe. The central portion of the body of the brake
shoe is removed so as to form two or more recesses or openings A between the
sides B and C, which latter are rigidly connected together by two or more bridges D.
It will be noted that these openings are of such extent that the brake shoe has the
full and maximum bearing upon the wheel between the points x and z and ¹,
respectively, which indicate the areas of the car-wheel which do not come in
contact with the rail under any conditions of service and are therefore never worn
by contact with the rail.
Between the points of minimum wear at on the crown of the flange and at x
on the tread, the brake shoe has a proportionate bearing or contact with the wheel
tread and flange, designed to simply even up or compensate for the proportionate
wear of the wheel by contact with the rail. It will be observed, however, that
with my brake shoe not only is the tread of the wheel dressed, but also the flange,
which latter is always worn in practice by contact with the rails in turning curves,
my shoe not only dresses the outside and crown of the flange, but also dresses the
inside and throat of the flange in approximately the proportion necessary to
compensate for the wear thereof so as to maintain the outlines or contour of the
flange as well as the tread of the wheel.
The brake shoe represented in the drawing illustrates the simplest and preferred
embodiment of my invention, but obviously many modifications in the shape of the
shoe as a whole and of the opening therein and of the bridges connecting the two
main parts of the shoe, without departing from the spirit of my invention so long
as the essential feature thereof is retained, which results in the proportionate
dressing of the tread and flange of the wheel to preserve and maintain the original
outline or contour thereof. For instance, more bridges might be added only a
portion of which bear upon the wheel, or the holes A might be spanned by a web
at the back of the shoe, which would result in converting such holes into recesses
in the inner or working face of the shoe. Then again, either with webs or bridges
connecting the main portions B and C of the shoe, the bridges may be so cut away
on the inner face of the shoe as to have no bearing on the wheel over the area of
maximum wear, although a slight wear of such area is preferable because in such
case the dressing effect of the shoe would be almost identical with that of a lathe
when the wheel is being turned and trued. All such modifications, however, are
very obvious ones and would be within the scope of my invention, and many other
changes of a like character will readily suggest themselves to one skilled in the
art to which my invention appertains.
Another feature of great practical importance is the reduction in the weight of
a shoe of this character which is invariably made of steel or iron, which reduction
not only avoids the liability of the shoe to tilt or cant in service, which results in
uneven wear of both the shoe and wheel, but also effects a substantial economy
in the cost of manufacture of the shoe as it saves a large amount of metal which
has heretofore been useless in the shoe and had to be discarded as waste or scrap
when the shoe was worn out, the saving thus effected being from a third to a half
of the total amount of metal heretofore necessary in this class of shoes.
I am aware that prior to my invention dressing brake shoes have been
constructed having recesses in the face thereof over the area of maximum wear
of the car-wheels, and also with wearing faces designed to proportionately wear
the tread of the car-wheel, but I am not aware of any brake shoe prior to my
invention in which the wearing surface of the shoe is proportioned to the wear on
the entire tread and flange of the wheel, including the area of wear upon the
throat and crown of the flange.

page_text: 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 brake shoe having continuous wearing surfaces to bear upon those portions
of the wheel which do not make contact with the rail, that portion of the shoe
between such continuous wearing surfaces being recessed or cut so as to leave a
reduced and substantially uniform wearing surface over the area of maximum wear
of the rail upon the wheel, approximately from y to y¹, and gradually increasing
wearing surfaces between said reduced portion and the said continuous wearing
surfaces, approximately from y to x and y to x, substantially as and for the
purpose described.
2. A brake shoe adapted to work upon both the tread and flange of a car-wheel,
provided with irregularly shaped recesses or openings extending between the points
of minimum wear of the rail upon the wheel, approximately from to a¹, so as to
leave continuous wearing surfaces beyond or at each side of said openings a
reduced and substantially uniform wearing surface over the area of maximum wear
of the rail upon the wheel, and gradually increasing wearing surfaces between
such reduced portion and the continuous side portions, substantially as described.
3. A brake shoe having continuous wearing surfaces to bear upon those portions
of the wheel which do not make contact with the rail, that portion of the shoe
between such continuous wearing surfaces being recessed or cut out so as to leave
a reduced and substantially uniform surface over the area of maximum wear of the
rail upon the wheel, approximately from y to y³, and a gradually increasing
wearing surface between said reduced portion and the continuous wearing surface
at the inner edge of the shoe, approximately from y¹ to x, substantially as and for
the purpose described.
DAL 1 T11004
HASELTINE, LAKE & Co.,.
45, Southampton Buildings, London, W.C., Agents for the Applicant.