IMPROVEMENTS IN PNEUMATIC RAILWAY BRAKES
Year: 1882

page_text: LETTERS PATENT to John Imray of No 28 Southampton Buildings Chancery
Lane in the county of Middlesex for an Invention of IMPROVEMENTS IN
PNEUMATIC RAILWAY BRAKES Communicated to him from abroad by Adolphe
Wenger of Paris in the Republic of France Engineer.
PROVISIONAL SPECIFICATION left by the said John Imray at the Office
of the Commissioners of Patents on the 12th July 1882..
"
JOHN IMRAY of No 28 Southampton Buildings Chancery Lane, in the County of
Middlesex "IMPROVEMENTS IN PNEUMATIC RAILWAY BRAKES [Communicated
to him from abroad by Adolphe Wenger of Paris in the Republic of France
Engineer.]
This invention relates to improvements in several parts of the apparatus for
working railway brakes pneumatically in the manner described in the specification
to Letters Patent granted to me on the 5th January 1881 N° 51 for an invention
communicated to me from abroad by Adolph Wenger.
According to the present invention instead of employing a stuffing box for the
rod of the brake piston, a small piston packed with cup leather is fixed on the rod
and this piston works in a small cylinder formed within the cover of the main
brake cylinder. The small piston is faced with a packing washer which when the
piston is at the extreme of its outstroke seats as a valve against a boss of the
cylinder cover preventing leakage. The equilibrium valve arrangement employed
for equalising the pressure in the brake cylinder and in the train pipe used for
taking off the brakes consists of a cylindrical box fitted with a piston packed with
a cup leather and loaded by a weight or spring. On the one side of the piston
there is a communication to the train pipe and on the other side there is a com-
munication to the brake cylinder and a passage to the outer air governed by a
valve or slide attached to the piston, so that when the piston is moved by an excess
of pressure in the brake cylinder this valve is opened relieving this excess by
escape. Instead of employing a check valve in the communication from the
braking train pipe to the brake cylinder, a piston is arranged in a cylindrical
Price 621

page_text: cavity, this piston being packed with a leather cupped in such direction that air
passes it freely from the pipe to the cylinder but air cannot return from the cylinder
to the pipe. The piston is arranged to move a little to and fro to prevent adhesion
of the leather to the cylinder. The brakes may be worked by a single train pipe,
that for taking off the brakes communicating with each brake cylinder through an
equilibrium valve such as is described above. On the other side of the cylinder is
provided a discharge cock consisting of a conical hollow plug which is pressed into
its seat by a spring and which has a lateral aperture so that when the plug is
turned into a certain position there is communication from the brake cylinder
through it and through its lateral aperture and a corresponding aperture in its
seating to the open air. The cocks employed for the communications from the train
pipe have the large ends of their conical plugs covered and subject to the pressure
which causes them to fit in their seatings, the handles of the cocks being fixed on
the projecting smaller ends of the plugs. The couplings employed for connecting
the train pipe from carriage to carriage are like those described in the Specification
above referred to. Similar couplings are applied to the ends of the metal pipes on
the carriages, so that a piece of flexible tube provided with similar couplings can be
employed to effect the junction from the pipe of one carriage to that of the next.
For connecting to the brake blocks, the rod worked by the brake piston is linked
to a lever mounted on the carriage frame and this lever has jointed to it one end
of another lever which at the opposite end is linked to the cross bar connecting
the blocks on one side of the pair of wheels and at about its middle is linked to a
third lever which is linked to the cross bar of the other pair of blocks, so that
when the lever is moyed by the brake piston both pairs of blocks are pressed
simultaneously against the wheels on their opposite sides, and the arms of the levers
are so proportioned that both pairs of blocks are equally strained against the
wheels. The third lever may be connected to the rod which is worked by the
ordinary screw gear for applying the brakes by hand.
For compressing the air for working the brakes a steam cylinder and a pump
cylinder are arranged in line, their pistons being connected to one rod. At the
bottom of the steam cylinder is fitted a slide attached to a hollow cylindrical sleeve
within which moves freely a collar on a prolongation of the piston rod. When the
steam piston approaches the end of its down stroke it pushes down the sleeve thus
moving the slide so as to admit steam below the piston and allow the steam to
escape from above it. When the steam piston approaches the end of its upstroke
the collar on its rod meeting the upper part of the sleeve moves it upwards and so
shifts the slide to admit steam above the piston and discharge from below it. The
movement of the sleeve does not directly shift the main slide of the steam cylinder
but shifts a small slide which causes the steam to move in the one or the other
direction the main slide. This main slide is in the form of three pistons of equal size
and a fourth piston of larger size all fixed on one rod and governing ports leading to
and from the cylinder. When the small slide is moved by the sleeve as above
described in one direction, steam admitted to one cavity of the main slide presses it
in the one direction so as to open one of the cylinder ports to the steam supply
and the other to discharge, and when the small slide is moved in the opposite
direction by the sleeve the pressure moves the main slide so as to reverse the supply
and discharge for the two ends of the steam cylinder.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Imray in the Great Seal Patent Office on the 12th January
1883.
JOHN IMRAY of No 28. Southampton Buildings Chancery Lane in the County of
Middlesex "IMPROVEMENTS IN PNEUMATIC RAILWAY BRAKES" A communication
to me from abroad by Adolphe Wenger of Paris in the Republic of France
Engineer.
This invention relates to improvements in several parts of the apparatus. for
working railway brakes pneumatically in the manner described in the Specification
to Letters Patent granted to me on the 5th January 1881 No 51 for an invention
communicated to me from abroad by Adolphe Wenger.
The said improvements will be readily understood on reference to the accompanying
drawings.
According to the present invention instead of employing a stuffing box for the
rod of the brake pistons C, Fig. 1, a small piston E packed with cup leather a is
fixed on the rod D and this piston works in a small cylinder B formed within the
cover of the main brake cylinder A. The boss b of the small piston is faced with
a packing washer c which when the piston is at the extreme of its outstroke seats
as a valve against a boss of the cylinder cover preventing leakage. Another
improvement relates to the equilibrium valve arrangement employed for equalising
the pressure in the brake cylinder and in the train pipe used for taking off the
brakes. One of these valves is arranged at each carriage on the branch leading
from the train pipe to the brake cylinder This valve has for its object to
produce rapidly and maintain the equilibrium between the discharge pressure of
the brake cylinders and that of the discharge pipe. It consists essentially as
shewn at Figs 3, 4, and 5, in vertical section, elevation and plan, of a cylindrical
box divided into two chambers by a piston F packed with a cup leather e, or other
soft packing and loaded by a weight or spring. On the one side of the piston
there is a communication to the discharge train pipe by the branch G and on the
other side there is a communication to the discharge pressure of the brake cylinder
by the tube H, and a passage I to the outer air governed by a valve or slide
attached to the piston, so that when the piston F is moved by an excess of
pressure in the brake cylinder this valve is opened relieving this excess by escape
through I. At Fig. 3 the passage I is enclosed air tight by a leather f secured by
a screw ring g a conical plug h being made to enter the passage I. - At Fig 6 the
closing of the passage I is effected by a metal conical valve g ground on its seat g'
and connected to the piston F so as to be moved vertically thereby, but to have
lateral play so as to fit accurately on its seat notwithstanding the play of the
piston in the cylinder. A helical spring J acting on the upper part of the
piston and consequently on the valve, insures the hermetic closing of the escape
passage I.
As shewn at Fig. 7.in vertical section and in horizontal section at Fig 8, the
passage I can also be closed by a slide k pressed by a spring h against the opening
of the passage, until the discharge pressure of the brake cylinder, which acts
continuously by H on one of the faces of the piston F of the equilibrium valve,
shall be equal to that of the discharge train pipe which acts continuously at G on
the other face of the piston. At this moment the piston resumes its original
position and the small differences of pressure that may still exist on the two faces
of the piston are neutralised by the small leakages of this piston.
It is therefore never necessary to have an absolutely tight piston in the
equilibrum valve, as the differences of pressure are. but momentary, and because at

page_text: whatever period of applying or taking off the brakes the apparatus may be, the
two faces of the piston are always subjected, the one to the discharge pressure of
the pipe, and the other to the discharge pressure of the brake cylinder, which
pressures it is the object of the valve to maintain in equilibrio.
When the piston of the equilibrium valve is provided with a cup leather as on
the drawing, this has its edges turned in the direction of the brake cylinder, so that
the air passes-readily from the train pipe to the cylinder; but with much greater
difficulty from the cylinder to the pipe.
The arrangements of these equilibrium valves described, insure the rapid action
of the brake, and the "moderability," as the discharge pressure of the brake
cylinder is always put in equilibrio with that of the discharge pipe. In modifying
the latter, the discharge pressure of the brake cylinder is correspondingly modified,
and the pressures become equal.
The check valve of the braking train pipe is constructed, as shewn in the section
at Fig. 9, of a metal box L divided by a piston M with cup leather, into two
compartments, of which one. communicates continuously with the braking train
pipe by the branch N, while the other communicates by O with the space of the
brake cylinder containing the braking pressure. The cup leather has its edges
turned towards the brake cylinder, so that the braking pressure passes readily
from the pipe to the cylinder, and with difficulty from the cylinder towards the
pipe. The piston M. may have a slight longitudinal motion, in order that the cup
leather may not in course of time stick at a certain point on the surface of the
cylinder. All or some of the brake cylinders of a train may be worked by a single
train pipe, namely the discharge pipe. In this case the check valves (Fig. 9) are
only placed on the brake cylinders of the carriages having the two train pipes.
For example, the locomotive and tender may be provided with the two train pipes,
and the other part of the train be provided with only one pipe. When the brake
cylinder has only one pipe, it is arranged as shewn in section at Fig 2. On one
side is the discharge pipe X, between which and the cylinder is the equilibrium
valve. On the other side of the cylinder is the discharge cock P communicating by
a pipe with the two spaces of the brake cylinder containing the braking pressure.
The discharge cock permits, in case of accident, of the discharge of the braking
pressure, and consequently the taking off of the brakes, which have been previously
applied. It is shewn separately at Fig. 10. It is a cock with hollow plug j,
made slightly conical, arranged in a casing P and pressed by an internal spring
so as to insure its air-tight working; it is turned by a handle k. The air escapes
when the openings m n are opposite each other. All the cocks from the train pipe
are constructed on the same principle, so as to insure an air tight closure. These
cocks, one of which is shewn at Fig. 11, are actuated from below; the plug Q has a
groove o permitting the fluid pressure to act on the top of the plug and cause it to
be pressed against the casing E
The couplings shown at Fig. 12, for connecting the train pipes R from carriage
to carriage are like those described in the Specification above referred to, similar
couplings being applied between the metal pipes R and the caoutchouc tubes S, in
order that a defective flexible tube may be readily removed and replaced by another.
The train is provided with a number of flexible tubes having half coupling at
each end, one of which connects with the metal pipe of the carriage, and the other
with the flexible tube of the next carriage, the two couplings being precisely the
same, and constructed as shewn in section at Fig. 13 and in plan at Fig. 13
It is somewhat simplified from the former coupling; the hook p of the one part
engages with the projection 9 of the other part. As shewn at Fig. 14 each pair of
wheels. T is acted upon. by four. brake blocks r r operating on both sides of the
wheels. The pull of the piston of the brake cylinder acts through the rod 8 on a
levert which transmits the strain to a second lever u acting on the two brake
blocks on the same side; the lever u transmits the strain through the.rod v to a
third lever u suspended from a fixed point and. acting on the other two brake
ɩblocks. Fig. 15 shews a side view of the levers t and u and their connection, The

page_text: blocks are mounted upon a transverse beam of equal resistance and the strain is
applied at the middle of the beam.
In order that the brakes may also be operated by the hand screw, the lever u
is jointed to a lever t¹ acted upon by the rod s¹ of the screw brake gear. The rod
forms a fixed point when the atmospheric brakes are used, and vice versa.
:
Figs. 16 and 17 shew another arrangement of the brake levers consisting of the
double cheeked levers U U¹, V V¹, one pivotted upon and within the other. The
ratio m: n of the small lever V. is equal to the ratio p: q of the larger lever U; if
in the two suspension rods Z Z the ratio : y is the same, the effect of the
pressure will be equal on each brake block. The lower extremities of the levers U
and V act upon the draw rods Z¹ Z³ which transmit the strain by means of the
transverse bars to the two lower ends of the suspension rods Z of the brakė
blocks.
The rod 8 of the brake piston is connected to the small lever at a¹ and the large
lever is jointed at b¹ to a fixed support on the carriage framing. When the brakes
are also worked by the screw gear, the point.6 is actuated by the screw gear; the
points a¹ and b³ are then alternately made to form the fulcrum or the moveable
point. In this case of combined atmospheric and screw brake, the point c' on which
the levers are pivotted is suspended from a rod d'.
Figs 18 and 19 shew respectively a sectional elevation and a cross section of an
improved construction of compression pumps. It consists of two superposed
cylinders A¹ and B¹, of which the latter forms a double acting pump, the cylinder A¹
forming the steam motor cylinder, and containing a piston P¹. This piston has a
rod p' passing into a sliding chamber h¹, working loosely in a space formed in the
bottom of the cylinder. The bottom of the cylinder forms the steam chest,
receiving the steam from the boiler through an opening . The valve gear is
situated in a chamber at D¹, and is shewn at Fig. 19, the steam being made to
pass into the cylinder at one time through the upper opening n¹ and at another
time through the lower opening m². The small slide actuated by the sliding
chamber h², completes the apparatus. The valve apparatus for distributing the
steam consists of four pistons p², p³, p*, p³, fixed on one and the same stem.
piston p² has double the surface of piston p; the pistons p³ pt are of equal
diameter and intermediate between p² and p³. These pistons p³ and p¹ in moving
to the right or to the left, cause the apertures m¹ and n¹ to communicate either
with the exhaust E' or with the steam supply entering through the passages j
and k. These two pistons p³, p¹, which distribute the steam in the cylinder A¹ can
be replaced by an ordinary D slide.
The
The small slide in causing steam to pass from the passage o' behind the
piston p³, or in allowing the same to escape therefrom causes the motion of the
pistons p, p, to take place alternately in contrary directions.
The pump acts as follows. When the piston P¹ arrives at the bottom of its
stroke it pushes against the sliding chamber h', which moves the slide t³, uncovers
the opening o', which allows steam to pass behind the piston p². This being moved
thereby causes piston p³ to uncover opening m³ whereby the piston P¹ is driven
upwards. Before it reaches the end of its stroke, the extension p' by means of its
disc draws the sliding chamber h' and slide t² upward, causing the steam behind p*
to escape, so that by the return motion of the piston p³ the piston p* is caused to
uncover the opening n¹. Piston P¹ now peforms its downstroke.
The arrangement of the slide t' actuated by the sliding chamber h¹ and the rod
extension p¹ of the piston P¹ forms the essential feature of this improvement.
Having thus described the nature of this invention and in what manner the
same is to be performed as communicated to me by my foreign correspondent, I
claim:-
First. The construction of brake cylinder herein described with reference to
Fig. 1 of the drawing wherein small cylinders are formed on the cylinder covers in
which work pistons that are provided with cup leathers, and are fixed on the piston

page_text: rods, the latter being also provided with a leather or caoutchouc washer forming an
air tight joint against the cylinder cover.
Second. The construction of equilibrium valve as herein described with reference
to Figs 2, 3, 4, 5 and 6, arranged to equalise the pressure of the discharge pipe,
and the discharge pressure of the brake cylinder.
Third. The construction of check valve provided with piston and cup leather,
arranged between the brake train pipe and the brake cylinder, substantially as
herein described.
Fourth. The herein described arrangement whereby either the whole or part of
the brakes of a train may be operated by a single train pipe.
Fifth. The use of a discharge cock in combination with the brake cylinder
arranged and operating as herein described for taking off the brakes.
Sixth. The herein described construction of cocks wherein an air tight fit of the
plug is insured by means of the fluid pressure in the train pipe.
Seventh. Connecting the flexible coupling pipes to the metal pipe of a carriage
by means of a divided coupling similar to that by which the said coupling pipe is
coupled to the pipe of the next carriage, substantially as herein described.
Eighth. The herein described combination of brake levers whereby a uniform
pressure is insured on all the brake blocks, while at the same time the brakes can
be operated either by the atmospheric brake gear or by the ordinary hand screw
gear.
Ninth. The construction of air compressing pump, with steam distributing valve
gear arranged and operating as herein described with reference to Figs. 18 and 19
of the Drawings.
In witness whereof I the said John Imray have hereunto set my hand and
seal this Twelfth day of January in the year of our Lord One thousand
eight hundred and eighty-three.