IMPROVEMENTS IN BRAKE BLOCKS FOR STREET RAILWAY CARS OR OTHER VEHICLES."
Year: 1875

page_text: LETTERS PATENT to Thomas Miller, Ironfounder, of London Road
Foundry, Edinburgh, in the County of Edinburghshire, for the
Invention of "IMPROVEMENTS IN BRAKE BLOCKS FOR STREET RAILWAY
CARS OR OTHER VEHICLES."

page_text: hard iron or wood. When the block is made entirely of iron the friction
wears away the tread or tire of the flanged wheel as well as the flange
very rapidly. When the block is made of wood the wear upon the tread
or tire is reduced to a minimum, but the rolling of the wheel in the
rails causes the tread or tire to wear rapidly, while the edge of the
flange being acted upon by the wood block only does not wear, and
becomes daily deeper, and in consequence increases the friction of the
car in the rails. To overcome this objection I employ a composite brake
block having that portion bearing on the flange of the wheel made of
hard iron or steel, while I attach to this metal block another of hard
wood, which is formed to bear only upon the tire or tread of the wheel.
On the iron portion of the block I form the usual lug or bracket to
secure it to the brake bar. I also cast on it projections, upon which I
fit the wood block and secure it by bolts.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Miller in the Great Seal Patent Office on
the 23rd May 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
MILLER, Ironfounder, of London Road Foundry, Edinburgh, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fifth day of November, in the
year of our Lord One thousand eight hundred and seventy-five, in the
thirty-ninth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Thomas Miller, Her special
licence that I, the said Thomas Miller, my executors, administrators,
and assigns, or such others as I, the said Thomas Miller, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
BRAKE BLOCKS FOR STREET RAILWAY CARS OR OTHER VEHICLES,” upon the
condition (amongst others) that I, the said Thomas Miller, my exe-
cutors or administrators, by an instrument in writing under my, or

page_text: their, or one of their hands and seals, should particularly describe
and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Miller, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement :-
My Invention consists of improvements in brake blocks for tramway
cars, by which the objections hitherto found in existing blocks are
obviated.
It has been the practice to make blocks of a form which covers both
the tread and flange of the wheel, and to construct such block of hard
iron or wood. When the block is made entirely of iron the friction
wears away the tread or tyre of the flanged wheel as well as the flange
very rapidly. When the block is made of wood the wear upon the tread
or tire is reduced to a minimum, but the rolling of the wheel in the
rails causes the tread or tire to wear rapidly, while the edge of the
flange being acted upon by the wood block only does not wear and
becomes daily deeper, and in consequence increases the friction of the
car in the rails. To overcome this objection I employ a composite brake
block having that portion bearing on the flange of the wheel made of
hard iron or steel; while I attach to this metal block another of hard
wood, which is formed to bear only upon the tire or tread of the wheel.
On the iron portion of the block I form the usual lug or bracket to
secure it to the brake bar. I also cast on it projections, upon which I
fit the wood block and secure it by bolts.
For the purpose of carrying out my said Invention I will refer to the
accompanying Sheet of Drawings appended hereto. Figure 1 shows a
side elevation; Figure 2, a front elevation; and Figure 3 a section on
line a, b, of a tramway brake block.
Figures 1, 2, and 3 present my improved brake block arranged to suit
flanged wheels of tramway cars or other vehicles in which the treads of
the wheels do not extend beyond the rails on which the treads rest, and
the whole breadth of wheel, tread, or tyre is thereby equally worn,
while the flange, having no bearing, gradually increases in length in
proportion to the wear of the tread or tyre.

page_text: In Drawing Figure 2 that portion marked B I make of wood to give
a maximum of friction with a minimum of wear on the tread, while the
grooved part A. I make of metal, preferably white or chilled cast iron, to
grind down the flange each time the brake is applied. The iron and
wood portions B and A are fastened together by screws or bolts A³, A².
The bracket or shoe C, Figure 1, is fastened to the bearing parts B
and A of composite block by means of dovetail and projections and
screw B¹, as shewn, and this shoe C on being fixed to the brake bar and
hanger of vehicle may become permanently attached thereto, and only
the wearing parts A and B renewed when they wear out.
Figures 4 and 5 show a modification of my Invention suited to
flanged wheels of railway carriages, wagons, or other vehicles, the
treads or bearing parts of which are wider than the rails on which they
rest, and which wheels require to be ground not only on the flange but
also on the portion of tread or tyre which ordinarily runs beyond the
rail in order that both flange and outer portion of tyre or tread may
be reduced at same rate as that running on the rail; E and F, Figures
4 and 5, are the portions of the block bearing on the flange and pro-
jecting tread, and these I form of hard metal, as herein-before described;
G being the part bearing on the portion of tyre subject to greatest wear,
I form of wood, which bears on the part D. The whole are fastened
together by screws or bolts, or in any convenient manner. The brake
block may be fixed to the brake bar in a similar manner to that already
described.
Having now described and ascertained the nature of my improve-
ments, and the manner in which the same may be carried into effect,
I would have it understood that I do not confine myself to the exact
details herein-before described, but what I claim is, constructing
composite brake blocks substantially in the manner and for the
purposes herein set forth and described.
In witness whereof, I, the said Thomas Miller, have hereunto set
my hand and seal, this Twenty-second day of May, in the year
of our Lord One thousand eight hundred and seventy-six.