Improvements in or Applicable to Vacuum Brake Mechanism.
Year: 1888

page_text: PROVISIONAL SPECIFICATION.
Improvements in or Applicable to Vacuum Brake Mechanism.
I, JAMES GRESHAM of the firm of Gresham & Craven of Craven Iron Works,
Salford Manchester, in the County of Lancaster, Engineers and Machinists do hereby
declare the nature of the said invention to be as follows:-
Firstly. My invention relates to and consists in combinations and arrangements
of mechanism to be applied to, or combined with, automatic brake cylinders and
vacuum chambers, and though applicable to all automatic brake cylinders and vacuum
chambers, it is more especially intended for trains made up of a great number of
vehicles say 50 vehicles more or less, and its object is to obtain automatic arrange-
ments to admit the air to the brake cylinders more rapidly than it can pass
through the train pipe merely, so as to apply the brakes more quickly in cases of
emergency.
The ordinary arrangement of mechanism will admit air through one opening or
valve to the train pipe and thus to the brake cylinders rapidly enough for ordinary
stoppages of the train when the train is to be brought to rest without shock, and
these ordinary arrangements with the automatic valve mechanism in the guards vans
for admitting air into the train pipe on emergencies act very rapidly to put on all the
brakes throughout a train, but the object of my present improvements is to obtain
means by which automatic valve arrangements for admitting air into the brake
cylinder, are or may be applied to each brake cylinder and vacuum chamber separately
so as to act very promptly in cases of emergency when the brakes have to be suddenly
applied.
My improvements are combined with the ordinary arrangements of valve mechanism
for making communication with the cylinder or casing and vacuum chamber, on
both sides of the piston or diaphragm, and the train pipe, such as described in the
specifications of Letters Patent granted to me Numbered 16,439. A.D. 1884, which
arrangements consist of a ball valve, sliding cage for it, diaphragm and lever for
acting upon the sliding ball valve cage, when the valve is to be drawn from its
seating.
This ball valve allows air to be drawn from cylinder or casing and vacuum chamber
on both sides of the piston or diaphragm for actuating the brakes, but when acting
automatically prevents air from the train pipe from passing to the vacuum chamber,
or upper side of the piston or diaphragm when air is admitted into the train pipe to

page_text: apply the brakes, the pressure of the air so admitted then only acting on the under
side of the piston or diaphragm the vacuum being retained by the ball valve on the
upper side, as is well understood.
As before said my present improvements are combined with the apparatus above
referred to, of each vacuum chamber and brake cylinder, and consists of a valve
arranged in a casing free to move endways and when at its extreme in one position
it is close upon its seating and prevents air from passing to the passages leading to
the lower side of the piston or diaphragm, but when moved from its seating air can
freely pass-The stem part of this valve is connected with a diaphragm which on
one side is open to the train pipe and on the other side to the atmosphere through
holes formed in the sides of the casing for the valve.
or
The stem part of the valve is hollow and through it air can pass between the
train pipe and vacuum chamber and cylinder or casing, and all the air. required to
pass to the underside of the piston or diaphragm to apply the brakes rapidly enough
for ordinary stoppages without shock can pass through the hollow stem of the valve,
as the Driver or Guard only admits air slowly for such ordinary stoppages, but in
the case of emergency or when air is admitted suddenly by the severance
separation of the train pipe, then the pressure of the air admitted into the train pipe,
cannot pass quickly through the hollow stem of the said valve and its diaphragm is acted
upon to open the valve and admit air directly from the atmosphere through the holes in
the sides or ends of the valve casing to pass the valve and enter the passages leading
to the underside of the piston or diaphragm and thus apply the brakes.
The said valve is or may be constructed and arranged in a variety of ways and
in some cases a ball or other valve arrangement is or may be used which will leave
open the passage corresponding to that in the stem of the said valve, in the ordinary
working of the brake apparatus, but which will entirely close the said passage corre-
sponding to that in the valve stem, in the case of emergency, when air is admitted
into the train pipe to its full capacity.
Secondly. My invention relates to the gland or packing arrangements for the piston
or diaphragm rods of vacuum brakes and consists in an improved construction and
arrangement of the same.
The ordinary india rubber or elastic packing ring which is somewhat similar to an
hydraulic packing ring and either acts upon the piston rod with so much friction as
to obstruct its proper working, or when made thin and two pliable it is ineffective,
or turns up after being some time in use-The object of my invention is to remedy
these defects.
My improved packing ring is made of india rubber or other suitable elastic
material and in section in the lengthway of the piston rod is curved with
its middle part towards the piston rod and the two ends of the elastic ring are held
between flanges, a metal ring and cap or cover ring, which cap ring is in some
cases formed in two parts dispensing with the said metal ring-The middle
part only of the elastic ring touches and comes close against the sides of the piston
rod.
Air is admitted to the exterior of the carved elastic ring so as to press upon it,
especially upon that edge of it, the opposite inner side of which is in communication
with the vacuum when existing under the piston or diaphragm-thus keeping the
elastic ring sufficiently close to the piston rod to prevent leakage of air past it; when
the brakes are to be held off the wheels.
This improved construction and arrangement of elastic packing ring also gives way
to the required extent to suit the lateral movements of the piston rod when actuating
the brakes and to wear and tear.

page_text: COMPLETE SPECIFICATION.
○ Improvements in or Applicable to Vacuum Brake Mechanism.
ياء
I JAMES GRESHAM of the firm of Gresham & Craven, of Craven Iron Works,
Salford, Manchester, in the County of Lancaster, Engineers and Machinists 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:
Firstly. My invention relates to and consists in combinations and arrangements of
mechanisin to be applied to or combined with automatic brake cylinders and vacuum
chambers and though applicable to all automatic brake cylinders and vacuum
chambers, it is more especially intended for trains made up of a great number of
vehicles say 50 vehicles more or less, and its object is to obtain automatic arrange
ments to admit the air to the brake cylinders more rapidly than it can pass through
the train pipe merely so as to apply the brakes more quickly in cases of emergency.
The ordinary arrangements of mechanism will admit air through one opening or
valve to the train pipe and thus to the brake cylinders rapidly enough for ordinary
stoppages of the train when the train is to be brought to rest without shock and these
ordinary arrangements with the automatic valve inechanism in the guards vans for
admitting air into the train pipe on emergencies act rapidly to put on all the brakes
throughout a train but the object of my present improvements is to obtain means by
which automatic valve arrangements for admitting air into the brake cylinder are or
may be applied to each brake cylinder and vacuum chamber separately so as to act
even more rapidly in cases of emergency when the brakes have to be applied
suddenly.
My improvements are combined with the ordinary arrangements of valve
mechanism for making communication with the cylinder or casing and vacuum
chamber on both sides of the piston or diaphragm, and the train pipe, such as
described in the specification of Letters Patent granted to me Numbered 16,439
A.D. 1884, which arrangements consist of a ball valve, sliding cage for it, diaphragm
and lever for acting upon the sliding ball valve cage, when the valve is to be drawn
from its seating.
This ball valve allows air to be drawn from a cylinder or casing and vacuum
chamber on both sides of the piston or diaphragm for actuating the brakes, but when
acting automatically prevents air from the train pipe from passing to the vacuum
chamber or upper side of the piston or diaphragm when air is admitted into the train
pipe to apply the brakes, the pressure of the air so adinitted then only acting on the
under side of the piston or diaphragm, the vacuum being retained by the ball valve
on the
upper side as is well understood..
As before said my present improvements are combined with the apparatus above
referred to of each vacuum chamber and brake cylinder and consists of a valve.
arranged in a casing free to move end ways and when at its extreme in one position
it is close upon its seating and prevents air from passing to the passages leading to

page_text: the lower side of the piston or diaphragm directly from the outside atmosphere but
when moved from its seating air can freely pass-The stem part of this valve is
connected with a diaphragm which on one side is open to the train pipe, and on the
other side to the atmosphere through holes formed in the sides of the casing for the
valve.
The stem part of the valve is hollow and has a ball valve in it and through the
hollow stem part, air can pass between the train pipe and vacuum chamber and
cylinder or casing and all the air required to pass to the underside of the piston or
diaphragm to apply the brakes rapidly enough for ordinary stoppages without shock
can pass through the hollow stem of the valve and past the ball valve in it as the
Driver or Guard only admits air slowly for such ordinary stoppages, but in the case
of emergency or when air is admitted suddenly by the severance or separation of the
train pipe, then the pressure and quantity of the air admitted into the train pipe,
cannot pass quickly through the hollow stem of the said valve (which has a ball valve
in it which is then shut) and its diaphragm is acted upon to open the valve and admit
air directly from the atmosphere through the holes in the sides or ends of the valve
casing to pass the valve and enter the passages leading to the underside of the piston_
or diaphragm and thus apply the brakes.
:
Secondly. My invention relates to the gland or packing arrangements for the
piston or diaphragm rods of vacuum brakes and consists in an improved construction
and arrangement of the same.
The ordinary india rubber or elastic packing ring which is somewhat similar to an
hydraulic packing ring and either acts upon the piston rod with so much friction as
to obstruct its proper working, or when made thin and two pliable it is ineffective or
turns up after being some time in use-The object of my invention is to remedy
these defects.
My improved packing ring is made of india rubber or other suitable elastic material,
and in section in the lengthway of the piston rod is curved with its middle part
towards the piston rod and the two ends of the elastic ring are held between flanges,
a metal ring and cap or cover ring which cap ring is in some cases formed in two
parts dispensing with the said separate metal ring.
The middle part only of the elastic ring touches, and comes close against the sides
of the piston rod.
Air is admitted to the exterior of the curved elastic ring so as to press upon it
especially upon that edge of it, the opposite inner side of which is in communication
with the vacuum when formed and existing under the piston or diaphragm thus
keeping the elastic ring sufficiently close to the piston rod to prevent leakage of air
past it, when the brakes are to be held off the wheels.
This improved construction and arrangement of elastic packing ring also gives
way to the required extent to suit the lateral movements of the piston rod when
actuating the brakes and to wear and tear.
Fig. 1 is a sectional elevation through a brake cylinder showing my improvements
combined therewith.
Fig. 2 is a detached enlarged sectional elevation of the valve mechanism shown in
fig.. 1.
Fig. 3 is a sectional elevation of a modification of the valve mechanism.
Fig. 4. is an enlarged detached sectional elevation of the improved gland packing
arrangement for the piston or diaphragm rod of brake cylinders according to the
second part of my invention which is also shown applied. in fig. 1; and fig. 5 is a
sectional elevation of a modification thereof.
a is the brake cylinder or vacuum chamber, a¹ its trunnions, a² the cylinder inside
the chamber
a3 is the piston, as its rolling packing ring, as is the piston rod which
is connected to the levers and rods for actuating the brake blocks...
a
The parts above referred to by reference letters are the ordinary and well known
parts of a vacuum brake cylinder or chamber.
To the underside of the brake cylinder or chamber a, a casting is secured in
which are formed passages, one b¹ leading from the train pipe to the underside of the

page_text: 5
piston a or diaphragm (when a diaphragm is used) the other leading from a side
branch from the passage b' to a ball valve arrangement and to a passage to the
chamber or space above the piston a³ or diaphragm (when used) commonly called the
vacuum chauiber.
The ball valve is in a tube 63 which at one end fits and slides upon a nipple from
the casting b the end of which forms the seating of the ball valve 6' when in the
position shown in fig. 2.
The other end of the tube for the ball valve is enlarged and has holes in its sides
to admit air from the chamber surrounding it and into the enlarged end of the
O tube 63 a stem 6 screws which secures the middle part of a small diaphragın 6ª air
tight between a collar on it and the end of the tube bª.
The outer margin of the diaphragm 6 is secured air tight between the end of a
bush and the casting into which the bush is screwed.
This bush acts to guide the end of the stem and the latter is forked so that a
lever can be jointed to it (the flat view of which is shown in dotted line in fig. 2
at a right angle to its correct position).
The movement of this lever 6 in either direction withdraws the ball valve 64 from
its seating when it is required to admit air into the vacuum chamber.
The combination and arrangement of ball valve band mechanism above described
by letters of reference is the same as or similar to that described in the specification
of Letters Patent granted to me No. 16,439, and dated the 15th December 1884, and
is herein described in order that my present improvements may be more readily
understood.
To the casting b, another casting c is secured by bolts and flanges or by other
suitable means, and between the two castings b and c the outer margin of a
diaphragm c of india rubber or other suitable flexible material is secured air tight.
The middle part of this diaphragm c¹ is secured on the hollow stem of a valve c
against a shoulder thereon, and by means of a. ring c³ screwed upon the hollow stem
of the valve.
The lower part of the hollow stem is enlarged, and upon its lower face it has a
recessed projection to hold one edge of a ring of india rubber c or other suitable
elastic material.
Inside the enlarged part of the hollow stem a bush c³ with a flange is screwed, the
flange on this bush thus holding the elastic ring c in its place on the lower face of
the hollow stem which elastic ring c forms the facing of the valve, the seating c for
which is formed in the casting c, as shown.
Inside the hollow stem of the valve there is a seating formed for a ball valve c'
which rests in its normal position on cross bars cs formed in the casting, as shown
n fig. 2.
that descends into the
From cross bars on the casting there is a projection
centre of the hollow stem of tho valve c' as shown in fig. 2.
In the side of the casting c there are a series of small holes co which admit the
tmosphere to the exterior of the hollow stem valve c and to one side of the
liaphragm c. c is a branch from the casting c which is connected with the train
ipe by a flexible tube in the ordinary manner.
When a partial vacuum is formed in the train pipe the atmosphere on the exterior
f the hollow stem valve c acts upon the diaphragm. e' to lift and open it, but as it
Iso acts on the seating end of the hollow stem valve with greater force to close it
is valve is kept closed when there is a vacuum in the train pipes, and it also keeps
osed when air is admitted into the train pipes for ordinary applications of the brakes
d the weight of the hollow stem valve keeps it closed when the atmosphere both
side and outside of it is in equilibrium.
But if air is admitted suddenly and in full quantity as in case of emergency or the
verance of the train pipe the ball valve c is instantly lifted against its seating and
e pressure of air then inside the train pipe and that acting on the underside of tho
aphragm lifts the valve c from its seating, and this allows the external atmosphere
pass directly through the holes c into the train pipe and also to the cylinder on the

page_text: underside of the piston a" by the passage o as just before the hollow stem valve chas
lifted to its greatest extent the projection c will push and keep the ball valve c' away
from its seating and allow air to pass it.
The moment the first of these valves of a train nearest the point at which the air'is
admitted into the train pipe has lifted to allow air to pass to the train pipe all the
other valves (c and c) in the train operate automatically to admit air directly into
the train pipe, and to the brake cylinders on the underside of the pistons a³.
When the brakes have been applied the valves e² and c assume the positions shown
in fig. 2.
.
Fig. 3 shows a modification of the arrangement illustrated by fig. 2.
The parts in the casting bare substantially the same as those shown in fig. 2 except
that the projection c is not required in this case.
There is a hollow stem valve c³ with an elastic facing e arranged and held same as
shown by fig. 2, and inside the hollow stem there is also a seating for a ball valve and
also a ball valve c' as in fig. 2.
But instead of a diaphragm (e) being connected with the hollow stem as in fig. 2
there is an elastic facing d held between a shoulder on the stem c² and a flanged disc d'
upon it secured by a nut
.
This clastic facing d comes upon a seating formed on a disc or ring fitting a
recess in the casting c as shown and held air tight by and against the elastic packing
placed between the two castings b and c.
Both elastic facings c and d rest upon their respective seatings when the valve c'
is closed and thus form a differential valve-The atmosphere admitted on the exterior
of the valve through the holes 10 in the side of the casting c acts upon both valves
but holds them upon their seatings, owing to the larger area on the lower valve having
the seating e when there is a partial vacuum in the train pipe and also when the air
in the interior and on the exterior of the valves is equal in pressure the weight of the
valves in this case keeping them closed.
In some cases an annular channel d is made in the underface of the metal of the
lower valve above the elastic facing and small holes are drilled to allow the atmos-
phere to pass from the holes co to this annular channel d.
This arrangement allows the elastic india rubber facing to be very slightly
pressed upwards into the annular channel, when the valves are down on their seatings,
and the pressure of the exterior air, acting in the annular channel d¹ to press down the
elastic facing e upon its seating, thus ensures that both valves will be close upon
their respective seatings when there is a partial vacuum in the train pipe.
When a large admission of air is made to the train pipe the valve will be
lifted against the seating and the valve c² will be raised until the guide. wings (5
with which it is provided, come in contact with the back of the disc d³.
This will admit air directly from the atmosphere into the train pipe and the Brake
cylinder under the piston a³.
When the brakes have been applied the weight of the valves will bring them
into the position shown in fig. 3.
:
Figs. 4 and 5 illustrate on an enlarged scale detached the modes of carrying out
the second part of my invention.
as the piston rod, a, bush through which the piston rod passes, this bush being
inserted in the end of the cylinder a as shown in fig. 1.
The modification of packing gland shown in fig. 1, is also that shown detached
and on an enlarged scale by fig. 4.
The packing ring e is made of india rubber or other suitable elastic material or
composition of the sectional form shown in fig. 4.
The elastic ring e has two flanges e¹ one of. which comes against the face of the
bush a as shown, the other flange of the ring e comes against the inside of a skeleton
cap, that is, a plate e having flanges to secure it by bolts screwed into the end of
the cylinder a as shown, in fig. 1 and arms carrying a disc or ring et.
.
Between the flange of the elastic ring e there is a metal ringe inserted with
holes in it to admit the atmosphere to the cavity between the elastic and metal

page_text: ring, the pressure thus obtained when a partial vacuum is formed in the cylinder
keeps the elastic packing ring e pressed close against the sides of the piston rod a³.
There are grooves in the two edges of the metal ring and in the face of the
bush a so that when the cap e is screwed tight the elastic material of the ring e
will be pressed into these grooves and give better hold and make the joints more
certainly air tight.
This improved packing gland admits of slight lateral movements in the piston
rod a'.
Fig. 5 shows a similar modification to that illustrated by fig. 4 except that the
plate and metal ring of fig. 4 are formed in one piece e and the ring or
disc e fig. 4 with a plate forms another piece e both parts e and are secured
to the cylinder by the same screws passing through the flanges of both parts.
The part marked as in this modification is the bottom of the cylinder, and not a
bush in it and the rod a' in this case, can move laterally as required in the case
of a fixed cylinder a or where a diaphragm is used in place of a piston.
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. For use with vacuum automatic brake apparatus the improved construction of
supplementary valve apparatus arranged substantially as herein described and operating
to admit the external air directly to the train pipe and to one side of the brake piston
upon the vacuum in the train pipe being suddenly destroyed.
2. For use with vacuum automatic brake apparatus a supplementary valve apparatus
arranged and operating substantially as described with reference to figs. 1 and 2. and
comprising a valve c seating against and working in conjunction with a diaphragm
mounted differential valve, which upon a sudden and considerable increase of
pressure in the train-pipe occuring, rises and permits the external air to pass directly
to the train pipe and to one side of the brake piston.
3. For use with vacuum automatic brake apparatus the modified construction of
supplementary valve apparatus substantially as described with reference to Fig. 3 and
comprising a valve e seating against and working in conjunction with a double seated
differential valve c² for the purposes referred to in the last preceding claiming
clause.
4. The combination with ordinary ball valve mechanism for operating vacuum
automatic brakes of supplementary valve apparatus substantially as hereinbefore.
described; the former being adapted for use with ordinary applications of the brakes,
and the latter when circumstances require an exceptionally rapid application of the.
brakes throughout the train.
°
5. The improved means for packing the piston or diaphragm rod of vacuum brake.
apparatus substantially as described with reference to figs. 4 and 5 respectively and
comprising an elastic packing ring held in position by means of outwardly projecting
flanges, the atmosphere having access to its outer surface and serving to press its inner
face, which is by preference rounded, against the surface of the said rod.
Dated this Fourth day of January 1889