IMPROVEMENTS IN APPARATUS FOR APPLYING RAILWAY BRAKES, ALSO FOR EFFECTING COMMUNI- CATION BETWEEN Guards, PASSENGERS, & ENGINE DRIVERS
Year: 1872

page_text: LETTERS PATENT to Otho Glynn Bolitho, Lieutenant of the 3rd
Prince of Wales' Dragoon Guards, and of Penalverne, Penzance,
in the County of Cornwall, for the Invention of "IMPROVEMENTS IN
APPARATUS FOR APPLYING RAILWAY BRAKES, ALSO FOR EFFECTING COMMUNI-
CATION BETWEEN Guards, PASSENGERS, & ENGINE DRIVERS."
Sealed the 30th April 1872, and dated the 23rd February 1872.
PROVISIONAL SPECIFICATION left by the said Otho Glynn Bolitho at
the Office of the Commissioners of Patents, with his Petition, on
the 23rd February 1872.
I, OTHO GLYNN BOLITHO, Lieutenant of the 3rd Prince of Wales'
Dragoon Guards, and of Penalverne, Penzance, in the County of
Cornwall, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN
APPARATUS FOR APPLYING RAILWAY BRAKES, ALSO FOR
EFFECTING COMMUNICATION BETWEEN GUARDS, PASSENGERS, AND ENGINE DRIVERS,"
to be as follows:-
This Invention has for its object improvements in apparatus for
applying railway brakes, also for effecting communication between

page_text: guards, passengers, and engine drivers. For this purpose I employ air
or water conveyed by pipes to each carriage of the train having brakes
fitted to it; by means of pumping apparatus pressure can be applied to
the fluid in the pipes, and this pressure holds the brake blocks out of
contact with the wheels, but when the pressure is relieved the brakes
take hold of the wheels; this is accomplished in the following
manner-Each brake block is connected with the piston rod of a
piston working in a cylinder, and the fluid is admitted to both sides
of the piston; consequently (as the piston rod diminishes the effective
area of the side of the piston to which it is attached) the piston rod
moves outwards as far as it is permitted to go, and holds the brake
block off the wheel. When it is desired to bring the brake block
into contact with the wheel the pressure of the fluid in the supply
pipe is relieved by opening an escape valve; thus the pressure is
taken off the side of the piston having the larger area, but it is
retained on the other side by a valve which prevents the escape of
the fluid from this portion of the cylinder. When water is employed
air vessels are connected with the cylinder ends. The expansion of the
air drives back the piston, and brings the brake block in contact with
the wheel.
I usually employ two pistons in the same cylinder; their rods pass
out at the opposite ends of the cylinder each to the brake block which
it controls. The pistons approach each other to apply the brakes, and
move outwards away from each other to take the brakes off.
In place of connecting the brake blocks with the pistons so that they
operate upon them directly they may be so arranged as to operate
through interposed levers. By similar means brake blocks may be
pressed against the rails instead of upon the wheels.
In some cases I employ the fluid under pressure only for the purpose
of holding the brake blocks out of action, and use powerful springs to
apply the brakes whenever the pressure of the fluid is relieved. The
buffer rods may be arranged so that when pressed inwards they open
valves and let off the fluid pressure so as to cause the brakes to act.
To prevent the brakes being applied when they are not required, the
pressure of the fluid may be increased until it raises a piston against
the resistance of a spring, and so disconnects the escape valve. The
fluid is compressed by a pump into a reservoir (in connection with

page_text: which, if water be used, is an air vessel), and the fluid passes from the
reservoir into the pipes which supply the cylinder. There is a spring
piston regulator in connection with the reservoir; it acts on a valve
by which the fluid is admitted to the pipes; the regulator admits the
fluid to the pipes in quantity sufficient to maintain the pressure in spite
of minute leakage, but as soon as one of the escape valves is opened the
regulator closes the communication with the reservoir.
There may be an escape valve accessible from each carriage or com-
partment of the train, and by the use of these the passengers will be
able to call the attention of the guard and driver.
I provide in the guard van and on the engine a cylinder and spring
piston or similar contrivance in connection with a whistle, which is thus
caused to sound whenever the pressure in the communication pipe is
relieved.
Similar results may be attained by maintaining a vacuum in the pipė
in lieu of pressure.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Otho Glynn Bolitho in the Great Seal Patent
Office on the 22nd August 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, OTHO
GLYNN BOLITHO, Lieutenant of the 3rd Prince of Wales' Dragoon
Guards, and of Penalverne, Penzance, in the County of Cornwall,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of February, in
the year of our Lord One thousand eight hundred and seventy-two,
in the thirty-fifth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said Otho Glynn Bolitho,
Her special license that I, the said Otho Glynn Bolitho, my executors,
administrators, and assigns, or such others as I, the said Otho Glynn
Bolitho, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter

page_text: 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 APPARATUS FOR APPLYING RAILWAY BRAKES, ALSO FOR
EFFECTING COMMUNICATION BETWEEN GUARDS, PASSENGERS, AND ENGINE DRIVERS,"
upon the condition (amongst others) that I, the said Otho Glynn
Bolitho, executors or administrators, by an instrument in writing
under my, or 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
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Otho Glynn Bolitho, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained 1
in and by the following statement thereof, that is to say :-
This Invention has for its object improvements in apparatus for
applying railway brakes, also for effecting communication between
guards, passengers, and engine drivers.
In a convenient place on the train, usually upon the engine or tender, 2
I place an air vessel which is kept supplied with air under high pressure.
From this vessel the air is allowed to escape into a connecting pipe
running from end to end of the train so as to maintain a constant
pressure therein, except when a freer escape is given to the air from the
pipe than can happen from accidental leakage.
When the apparatus is in proper working order the connecting pipe is
coupled at each brake carriage (and it is desirable that all or nearly all
of the carriages of the train should be provided with brakes) with a
cylinder apparatus with pistons, which are connected with the brake
blocks. Whilst the pressure is maintained in the connecting pipe the 3
air under pressure comes upon both sides of the pistons.
The piston
rods somewhat reduce the effective area of the pistons on one side, and
consequently the pistons are held at the outer end of the cylinder, and
the brake blocks are kept of contact with the wheels.
When the pressure in the connecting pipe is reduced by the opening of 3
an air cock or otherwise, the valve of the cylinder annaratus is shifted

page_text: sectional elevation of the mechanism by which the air is let out of the
compressed air reservoir into the connecting pipe so as to maintain a
constant pressure therein except when the brakes are required to act.
a is a pipe leading from a compressed air reservoir, in which by means
of a donkey engine or otherwise a pressure is maintained considerably
above that desired in the connecting pipe; b is a three-way cock upon
the pipe a; when open it allows the air to pass into the connecting pipe c,
and by a side branch it passes into the cylinder d, in which is a piston e
pressed upon by a spring f. This piston constantly seeks a position of
equilibrium between the pressure of the air in the cylinder and the
pressure of the spring. The piston rod is connected with a slide 9 on
which a pawl h is carried. This pawl is adjustable along the slide g,
and on its position the pressure maintained in the connecting pipe c
depends. The pawl h takes into a notch in a wheel or arc 6' on the
plug of the cock b. When the pressure of air in the connecting pipe
falls from leakage or any other cause, the spring of moves the piston e
in the cylinder d until the pawl h turns the cock 6 sufficiently far to
admit air from the reservoir into the connecting pipe c. The cock b is
however in any case only slightly opened because if the loss of pressure
arose only from a small leakage it will be at once made good; the piston

page_text: will then return and the pawl will again close the cock. But on the
other hand if the fall of pressure is due to the opening of one of the air
cocks upon the connecting pipe the pressure may continue to fall after
the cock 6 has been slightly opened, but then the pawl h will leave the
notch in the wheel or arc 6', and the cock will remain so placed as to
allow a small continuous flow of air into the connecting pipe, sufficient
to restore the pressure in it when the air cock upon it is closed to take
off the brakes; i is a lever which is employed to put on the brakes from
the engine or tender; a bolt i¹ taking into the notches of the wheel or
arc b¹ connects the wheel or arc b¹ with the lever, and the lever is fast
upon the plug of the cock. By the lever i the cock 6 can be so turned
as to allow the air to escape at the outlet 62. The lever i then rests
against the stop g¹ on the slide g, which as the pressure in the connecting
pipe rapidly falls is moved by the piston e so as to replace the lever i
and the plug of the cock b, thus preventing the further escape of air as
soon as the pressure has fallen to a certain prearranged point sufficient
to produce a moderate action upon the brakes. The engine driver can
however on emergency, and this is a point of much importance, produce
a further escape of air, and consequently a more powerful action on the
brakes by a second action of the lever i; the lever i then passes the
stop g', to admit of which the lever may be jointed or the stop may be so
hung that the engine driver can readily throw it out of the way. By
moving the lever i in the opposite direction compressed air is readmitted
into the connecting pipe from the reservoir until the proper working
pressure is again attained, and then the stop 9 throws back the lever i;
the pawl h is again thrown in and the action is as before automatic.
Figure 4 is a plan; and Figure 5, a sectional elevation of a portion of
a brake carriage. a, a, are the wheels to which the brake blocks 6 are
applied; they are suspended from the carriage frame by links b', b'.
c is the connecting pipe, as before it communicates with a cylinder and
apparatus herein-after described, and from which two piston rods pass to
cross bars d, and these cross bars are fixed to the links 6' immediately
behind the brake blocks, so that when the piston rods move inwards the
brakes are applied.
Figure 6 is an horizontal section of the cylinder apparatus drawn to a
larger scale.
Figure 7 is a side view, and Figure 8 is a transverse section of the
cylinder with passages and valves in connection therewith. This section

page_text: is taken at the line 1, 1, Figure 6. a is the working cylinder; and b, a
cylindrical valve chamber formed with it in one casting, which is
Buspended beneath the body of the carriage by the links c, c.
The con-
nection is made to slotted lugs on the casting, so as not to interfere with
the play of the carriage springs; d, d, are two pistons in the cylinder a
with their piston rods d¹, d'; e is a pipe in direct communication with
the connecting pipe; it admits the air into the cylindrical valve
chamber 6 by a port 6¹ in its side. The air passes by the passage f past
the valve g into the passages h, h, and so the pressure comes upon the
outer side of each piston. The compressed air also passes between the
pistons by the passage i, the valve k allowing the air to pass in this
direction. The effective area of the outer sides of the pistons & being
lessened by the piston rods the preponderating pressure on the inner
sides forces the pistons apart, and the brake blocks (with which the
piston rods are connected through other parts as already explained) are
held off from the wheels. The valve chamber 6 contains a piston
valve 7, and a second smaller valve chamber 6* contains a smaller piston
valve m.
In the position in which the parts are shewn the valve / has
the pressure of the air on both its faces, the air being admitted from the
end of the cylinder a to the back of the valve by the passage n; a large
part of the area of the piston valve on this side is however occupied by
its rod, so that the pressure on the face of the piston valve is just com-
petent to keep the valve in the position in which it is shewn notwith-
standing the pressure upon the valve m. In the contrary direction
when the pressure in the connecting pipe is reduced the action on the
valve is as follows:-The pressure on the face of the valve is now less
than before in proportion to the reduction of pressure in the connecting
pipe; but the pressure on the back of the valve l, and also that upon
valve m, remains as before, the valves g and k preventing the compressed
air returning. The valve is consequently caused to move until the
valve m uncovers the outlet o; the air then flows out from between the
pistons until the valve m is so far relieved from pressure that the pres-
sure still remaining on the face of the piston valve is able to bring back
both land m. The piston valve m being several times smaller than the
piston valve 1, by so many times (approximately) will the reduction of
pressure between the pistons d, d, be greater than the reduction of
pressure in the connecting pipe. When the pressure is again raised in
the connecting pipe it forces its way between the pistons d, d, and so the
brakes are taken off. The piston rods are controlled so that they can
the

page_text: only move back the brake blocks sufficiently to clear the wheels, hence
very little motion of the pistons is required. The controlling stops are
adjusted by self-acting mechanism to compensate for the wear of the
brake blocks. p, p, are cross heads upon piston rods by which they are
connected with the cross bars attached to the brake blocks. The cross
heads p work in slotted stop plates q, q, and these are able to slide in
guides r, r, fixed to the cylinder covers; r¹, r¹, are racks fixed to the
guides r, r, and 8, 8, are pawls upon the stop plates q, which take into
the rack teeth. The action is as follows:-The slots in the stop plates q
limit the outward motion of the pistons when the brakes are taken off
and when they are put on. If the cross heads p come to the end of the
slots in the stop plates q before they are stopped by the brake blocks
resting upon the wheels the stop plates are moved inwards along the
guides so that they do not allow the pistons to separate as much as
before when the brakes are next taken off.
Figure 9 is a longitudinal section of a railway carriage; Figure 10, a
transverse section; and Figure 11, an end view of the same. a, a, are
levers within the several compartments of the carriage by which the
occupants can draw upwards the rod b, and this by a bell-crank lever c
gives motion to a longitudinal rod d ; is a lever on the plug of an air
cock which is thus opened:-The issuing air may cause a whistle ƒ to
sound. In moving the lever a a paper label which is pasted over it is
torn, so that it is easy for the guard to ascertain from what compartment
the apparatus has been called into operation. The motion of the longi-
tudinal rod d also causes a disc g to be thrown out from the side of the
carriage to attract the attention of the guard; the motion of the rod d is
transmitted to the disc by the crank levers and rods h; i, is a projection
which may be raised at the side of the line of rails to act upon the bar d
by means of the lever k.
In place of employing compressed air, as herein-before described (not
only to hold the break blocks away from the wheels when the breaks are
to be held out of action, but also to act as a spring to force the break
blocks against the wheels when the breaks are to be applied), the com-
pressed air may be used only for the purpose of holding the break
blocks away from the wheels when the breaks are to be held out of
action, whilst a metal or other spring or the weight may be employed
for forcing the break blocks against the wheels. In this case water
or other liquid might be used in place of air.

page_text: Having thus described the nature of my said Invention, and the
manner of performing the same, I would have it understood that I do
not confine myself to the exact details described; but I claim, —
1. The arrangement of apparatus for applying railway breaks; also for
effecting communication between guards, passengers, and and engine
drivers, substantially as described.
2. The construction of apparatus for applying railway breaks in such
manner that the break blocks are held out of action by means of air,
water, or other fluid under pressure, and are applied by springs or their
equivalents whenever the pressure of such fluid is released, substantially
as described.
In witness whereof, I, the said Otho Glynn Bolitho, have hereunto
set my hand and seal, this Twelfth day of August, in the year of
our Lord One thousand eight hundred and seventy-two.