IMPROVEMENTS IN STEAM AND HYDRAULIC BRAKES
Year: 1873

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVEMENTS IN STEAM AND HYDRAULIC BRAKES."-A communication
from abroad by John Fisher Taylor, of the City and County of
Charleston, State of South Carolina, United States of America.
PROVISIONAL SPECIFICATION left by the said Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 30th June 1873.
.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
3 County of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN STEAM AND HYDRAULIC BRAKES, to
be as follows:_

page_text: Secondly. To a method of first using one steam cylinder to put on the
initial pressure, and then another to put on the desired pressure, both
working against the pressure in an air chamber in connection with the
brakes.
Thirdly. To a method of forcing brakes against wheels by air pressure
when the latter is applied by the reversed action of the cylinder and
piston caused by the escape of the usual supply of some fluid from the
other end of said cylinder, as hereafter described.
In carrying out this Invention I employ two steam cylinders, to cach
of which is bolted a water chamber fitted with a ram attached to the
piston of the steam cylinder, the rams being of different diameters.
Both water chambers communicate by a pipe with the brake cylinders
hereafter described, by which the brakes are operated, the operation
being as follows:-Both steam pistons being at the rear end of their
cylinders, and both water chambers being filled with liquid, steam is let
on to the piston that has the larger ram, which forces the liquid out of
the liquid chamber and along the pipe to the chambers which operate
the brakes. This forces the brakes against the wheels and puts on the
initial pressure. Steam is then let on to the other piston with the small
ram, which forces the liquid out of its chamber along the same pipe and
puts on the force desired. A check valve is provided at the front or
discharge end of the first liquid chamber, which closing automatically
prevents the liquid entering the said chamber while the final force is
being applied. The brakes are relieved by reversing a hand lever which
takes all the pressure off the brakes and also off the check valve, and
then by reversing another hand lever the check valve is raised at the
same time that steam is let into the other end of the steam cylinder.
Both pistons are thus forced back, drawing back the liquid from the
brake cylinders, which by the aid of the air chambers hereafter
mentioned force the brakes clear of the wheels., All is thus made ready
for another operation. Guards are provided at the rear of the steam
cylinders with india-rubber cushions in them for the piston rods to abutt
against to prevent the pistons striking the cylinder heads. The brako
cylinders, of which there is one to each carriage, each consist of a liquid
and air cylinder hung by links from the framing of the carriage, and
attached to one of the extreme brake beams, which I will; distinguish as
No. 1, and connected to the other, which I will call No. 2, by bolts.
The said cylinder contains a piston whose rod is connected by a cross

page_text: head and side rods with the two middle brake beams, which I will call
Nos. 3 and 4, the operation of the brakes being as follows:-The
cylinder with all its attachments being secured to the brake beam No. 1
at one end of the carriage and connected to No. 2 at the other end by
bolts is free to move, and the cross head being connected by rods to the
middle brake beams Nos. 3 and 4 is also free to move. Water or other
liquid is forced into the cylinder at one end through the pipe which
connects with main supply direct from the liquid chamber and steam
cylinders on the locomotive before described; whereby the cylinder and
piston are forced in opposite directions, and the brakes Nos. 1 and 2 are
applied.
:
In order to cause the brakes to be applied in case of accident when
the pipes are broken an air chamber is provided communicating with
the other end of said cylinder. Air having been previously forced
through a check valve into said air chamber to a suitable pressure when
all the water has escaped from the cylinder the elasticity of the air in
the chamber will force the cylinder and piston in the opposite directions
to the previously described movement, thereby applying brakes Nós. 3
and 4 to the wheels, against which they will remain until relieved by
letting the air escape. I do not confine myself to this method of
attaching the cylinder and cross head directly to the brake beams, as
they may be secured anywhere about the carriage, and the power trans-
mitted to the brakes by any suitable arrangement of rods, levers, and
rock shafts, or to the usual hand brake gear.
-
I
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Alexander Melville Clark in the Great Seal Patent
Office on the 5th December 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirtieth day of June, in the year of our Lord
One thousand eight hundred and seventy-three, in the thirty-seventh
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Alexander Melville Clark, Her special licence-

page_text: A, A', are steam cylinders; B, B, water chambers; R, rams; C, a
check valve; D, a connecting pipe; E, guards; F, valve rod, connecting
steam and check valves; G, levers for lifting check valves; H, hand-
lever for operating valves; I, a steam valve; K, a steam chest; L,
5 (Figure 4) steam pipe; and M, exhaust pipe.
The operation is as follows:-Both steam pistons being at the rear end
of cylinders, and both chambers B being filled with water or other.
liquid, steam is let on to the pistons in the cylinder A that has the large
ram and the check valve (the one to the right, Figure 3), which forces
the liquid out of the chamber through the check valves and along the
pipe or hose to the liquid chambers which operate the brakes. This
forces all the brakes against the wheels and puts on the initial pressure.
Then steam is put on the other piston A¹ with the small ram which
forces the liquid out of its chamber along the same pipe and puts on
the force desired. The check valve having closed automatically prevents
the liquid from entering the first chamber while the final force is being
applied. To relieve the brakes one of the hand levers H is reversed,
which takes all the pressure off the brakes and also off the check valve,
the other hand lever being then reversed, which raises the check valve,
at the same time letting steam into the other end of the steam cylinder.
Both pistons are thus forced back to where they started from, drawing
the liquid back from the brake chambers, which by the aid of the air
chambers on the brake chambers force the brakes clear of the wheels.
All is thus made ready for another operation. The guards at the rear of
the steam cylinder with india-rubber cushions in them prevent the
pistons from striking the cylinder heads.
Figure 8 is a side sectional clevation; Figure 9 is a front clevation;.
Figure 10 is a plan view with half of air chamber in section.
Figure 11 is a front elevation showing a portion of the cylinder and
air chamber in section.
.The same letters in all the Figures indicate the same parts.
A is a liquid and air cylinder; B, a tight fitting piston; C, a piston
rod connecting cross head; D and E, E, side rods connecting cross head
to brake beams (Nos. 2 and 4, Figure 12); F is a liquid pipe connecting
with main supply direct from liquid chambers and steam cylinders on
the locomotive; G is a bracket; and H; H, links for supporting the
whole; 4 is an air chamber; A', an air valve; W is a valve opening. ;

page_text: outwards to let out any surplus liquid or air; C¹is a check valve to
attach air supply pipe or pump to; B1, B2, are the brake beams; T is a
portion of the truck frame or some other suitable support.
The operation of the brakes is as follows:-The cylinder with all its
attachments being secured to the brake beam No. 1 and connected by
bolts to No. 3 is free to move, and the cross head being connected by
rods to the brake beams Nos. 2 and 4 is also free to move. Water or
other liquid is forced into the cylinder A² through the pipe F, which
forces the cylinder and piston in opposite directions and applics the
brakes Nos. 1 and 2.
I provide as follows for applying the brakes in case of accident when
the pipes or hose are broken:-Air having been previously forced into
the air chamber by any suitable means, say to a pressure of 80 lbs. per
square inch, so that when all the water has escaped from the cylinder
the elasticity of the air in the chamber will force the cylinder and piston
in opposite directions to the previously explained movement, and apply
the brakes Nos. 3 and 4 to the wheels, against which they will remain
until relieved by letting the air escape. The air when forced into the
air chambers through the check valve c¹ will remain there ready for any
number of operations, as it can only escape through some leak, and
would only require restoring at long intervals. I do not confine myself
to this method of attaching the cylinder and cross head directly to the
brake beams, as they may be secured any where about the vehicle, and
the power transmitted to the brakes by any suitable arrangement of
rods, levers, and rock shafts, or to the usual hand brake gear.
Having described the nature of the Invention and the manner of
performing the same, I declare that what I claim as the Invention to be
protected by the herein-before in part recited Letters Patent is,―
1st. The method herein described of forcing brakes against wheels by
hydraulic pressure when the latter is applied directly from the pistons
of steam engines through the medium of rams attached to them, sub-
stantially as described.
2nd. The method herein described of first using one steam cylinder
to put on the initial pressure, and then the other to put on the desired
pressure, both working against the pressure in the air chamber.
3rd. The valve C or its equivalent arranged at the front or discharge
end of chamber B, substantially as and for the purposes set forth.

page_text: 4th. The method herein described of forcing brakes against wheels
by air pressure when the latter is applied by the reverse action of the
cylinder and piston caused by the escape of the usual supply of some
fluid from the other end of the said cylinder.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Fifth day of December, in
the year of our Lord One thousand eight hundred and seventy-
three..
Witness,
.HENRY W. DEWEY,
53, Chancery Lane,
London..
'
A. M. CLARK. (L.S.)