Improvements in or relating to Fluid Pressure Brake Systems for Railway Vehicles.
Year: 1893

page_text: Date of Application, 7th Nov., 1893-Accepted, 16th Dec., 1893
COMPLETE SPECIFICATION.
Improvements in or relating to Fluid Pressure Brake Systems for
Railway Vehicles.
1, WILLIAM THOMPSON BOTHWELL, of 90. Kinsington Avenue, Jersey City,
in the County of Hudson, and State of New Jersey, United States of America,
Gentleman, 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 :-
This invention has relation to an improvement in fluid pressure brake mechanism
and it has for its object to improve upon and perfect that class of mechanism by
which the speed of a train may be regulated and held under control while descending
long and dangerous grades and to provide for recharging the auxiliary reservoirs
of automatic air brakes while the brakes are applied without releasing them or with
the release of the brakes when desired; so that trains may with safety descend
dangerous grades, the delays incident to the adjustment of the brake mechanism
under each car before descending as well as after descending such grades being
dispensed with.
In the accompanying drawings I have shown one convenient embodiment of my
invention for accomplishing these various objects, in which:
Fig. is a vertical, longitudinal, central sectional view, illustrating parts in a
position with the brake off.
Fig. 2 is a similar view, illustrating the parts in a position with the brake on.
Fig. 3 is a section taken in the plane indicated by the dotted line x-x on Fig. 1,
looking in the direction of the arrow.
Fig. 4 is a perspective view of one of the castings or bushings for the third valve.
Fig. 5 is a perspective view of such third valve.
Fig. 6 is a perspective view of the check valve interposed in the port or passage
between the piston cylinder and third valve cylinder.
Fig. 7 is a perspective view of the check valve arranged in the port or passage
leading from the piston cylinder to the auxiliary reservoir.
In said drawing, I have shown a piston cylinder or casing A, with a head a,
covering one end, and provided with a screw-tapped aperture b, for the attachment
of a suitable connection from the brake cylinder, and the body of the casing or
cylinder A is also provided with a screw-tapped aperture c, for a similar purpose;
a plug f, being employed to close one aperture when the other is used.
A screw-tapped port or passage B is provided for connection with the storage or
auxiliary cylinder, and this port leads from an annular groove g, within the
cylindrical body of the casing or cylinder A. and is provided with a check valve V.
A longitudinal port or passage C, leads from the screw-tapped passage B, and
connects with the interior of the piston cylinder A, at or near the opposite end by
a port or passage D. A port or passage G, leads from the interior of the piston
cylinder to the aperture or passage for connection with the brake cylinder and an
exhaust port or passage H leads from the interior of said casing to the open air.
A reciprocatory piston-valve 1, is arranged within the piston cylinder A and is
provided with a head K and stem L.
The body of the cylinder A is provided in its bore with a lining M, which is
preferably formed of brass. This lining is turned out on its inner side as shown at N,
to provide a smooth surface for the head of the piston valve, and in this turned-out
portion is formed a circular series of transverse holes h, which lead into the annular
groove g, and which in turn communicates with the aperture or passage B.
This lining has formed upon it a valve-seat P, which has longitudinal guide
flanges for the valve and the exhaust port or passage, and also the port or passage G
extending through this valve seat as shown.

page_text: An exhaust slide valve is arranged on this seat and has a recess k, and a
passage. The valve also has a lug m, having an aperture n, to receive the stem
of the piston valve, and said valve is secured to the stem by collars, and a pin or
other suitable fastening devices. The piston head is provided on its inner side with
lugs p, which serve as stops for the inward movement of the piston valve when
brought against the shoulder q, of the lining.
Interposed between the head S and piston head is a spring R, which is carried
by the stem L.
S indicates a head for the end of the piston cylinder opposite the head a.
This head S is provided with a port or passage i, which leads from the interior
of the piston cylinder to the interior of a valve chest or casing T. This head
is also provided with a port or passage k², having a valve seat and leads from
the valve chest or casing T to a port or passage r, which latter port or passage
communicates with the passage C, in the piston cylinder and also with the passage B,
which leads to the auxiliary or storage cylinder. A check valve V is arranged
at the intersection of the ports or passages B, C, and r, and this check valve
which has a seat t, in the piston cylinder is provided with a transverse port u, and
a vertical or longitudinal port e, which communicates with the transverse port u.
W indicates a check valve which is arranged in the port or passage of
head S, and is backed by a spring so as to keep it normally seated, and close
communication between piston cylinder and auxiliary storage and the valve casing T.
The valve casing T is arranged on the head S and preferably in a plane at
right angles to the movement of the piston valve, and is provided centrally with
a screw-tapped port or passage 2 for connection with the line or supply pipe of
an air-brake system.
3 indicates a reciprocatory valve which I shall denominate the third valve..
This valve is of a form substantially as shown in Fig. 5 and is arranged within
the casing T as presently described.
Arranged within this casing T is a bushing or lining for the valve 3, and this
bushing is composed of two sections-an upper section 4 and a lower section 5
-which are let into the bore of the casing T, at opposite ends as shown, and
are secured against shoulders a' and ', by means of screw caps c', and ', and
suitable packing e; a vent aperture being provided in cap c¹ so as to offer
no obstruction by the enclosure of air to the free movements of the valve.
These bushings 4 and 5, are each reduced at their adjacent ends as shown at g¹
and to seat the valve head 6 which is placed within the casing T at the screw-
tapped aperture or passage 2.
The bushing 5 is reduced circumferentially at a point opposite the port or
passage i, of the piston cylinder, as shown at 4, and this reduced portion is
pierced with a number of holes for the admission of air from the line pipe to
the piston cylinder and vice versa. The valve 3 has an enlargement or head 6
about midway of its length, which is designed to seat against the adjacent
ends g' and ', of the bushings within casing T, and the stem is grooved longi-
tudinally at suitable points so as to form channels m', and n' extending from
opposite sides of said head or enlargement. One end of the stem of this valve
which plays within the bushing 4 has a head p' with suitable packing, as shown,
and the opposite end of the stem of said valve is externally threaded as shown
at to receive nuts r³, and a spiral or coiled spring & surrounds the rod and
bears at one end against the nuts thereon, and at the opposite end against a
shoulder in the bore of the bushing.
By this construction I am able to strengthen or weaken the force of the spring
by manipulating the nuts and consequently adjust the valve 3, for the air pressure
desired to be used. It is desirable that the head pl of this reciprocatory valve
should be slightly greater in diameter than that of the head 6 on the stem of the
valve, so that the pressure acting upon the underside of said enlargement may
afford a quicker movement should there be any leakage or other cause which might
possibly retard its movement.

page_text: The object of the third valve is to control and regulate the passage of air from
the line pipe to the piston cylinder and auxiliary cylinder and also from the piston
cylinder back to the line pipe. Before letting any air from the line pipe into the
piston cylinder or auxiliary cylinder, the spring s', will of course hold enlargement 6 of
the third valve down upon the seat of the bushing 5, and the force required to
raise said enlargement from the seat as thus described may be regulated by the
manipulation of the nuts so as to weaken or stiffen the spring. Now as air is let
in from the line pipe through the port or aperture 2, of the third valve casing, it
will pass into the bushing 4, through channels n' of the valve rod or stem above
enlargement 6 striking head p', will lift the enlargement 6 up to the seat g', of the
bushing and the air thus received within the bushing 4 will unseat check-valve W
and passing through passage, and the passages in the check valve V will be
carried to the auxiliary reservoir and also into the piston cylinder on the inner side
of the piston head. As quick as the air moves the third valve so as to seat its
enlargement 6, against seat g', the air will then pass from the line pipe through
port or passage 2, down through the channels m³, below enlargement 6, and into
bushing 5, after which it will pass out from said bushing through apertures / into
the circumferential groove k', and from thence through the passage i, to the piston
cylinder and against the piston head therein when said head will be forced inwardly
in the piston cylinder and the air thus admitted will pass out through the holes h,
of the lining into groove g, and lifting check valve V, will pass to the storage or
auxiliary cylinder and so to the piston cylinder on the opposite side of the piston
head as indicated by arrows in full lines.
When pressure has been reduced in the line pipe but to a point greater in force
than that exerted by spring s¹, some of the air on the forward side of the piston
head within the piston cylinder will return from said cylinder back through port i,
the port or recess k', holes or apertures l', into the bushing 5 and from thence
through channels m¹ back to the line pipe.
While when the pressure in the line pipe has been reduced to such an extent as
to allow the spring to act, such spring will draw down the third valve until its
enlargement 6 has been seated upon the upper end of the bushing 5, thereby
allowing the air in the storage cylinder passing through ports C, and D, to throw
the piston and valve Q so as to apply the brakes.
During this application of the brakes, air under a certain pressure can be let in
from the line pipe through the bushing 4, and the port or passage k³ to port or
passager, by unseating check valve W and from thence such air can pass to the
storage reservoir and to the brake cylinder respectively.
The device as shown in Fig. 2 of the drawings, illustrates the parts in a position,
as if the brakes were on. Now, to release the brakes, pressure should be increased
in the line pipe by the manipulation of the engineer's valve, and sufficient to over-
come the force of spring s. This will raise the head or enlargement 6 off of the
seat allowing the air to enter the bushing 5 and pass in the course indicated by
arrows in full lines, down and out through holes l', into the piston cylinder. This
will force the piston head inwardly so as to uncover the small holes h, in the lining.
The air will then flow from the line pipe through said holes into groove g, and from
thence through port or passage B to the storage cylinder. During this operation,
air will also pass through the ports or passages C and D, into the interior of the
piston cylinder on opposite side of the piston head, so that as the brakes are being
released, air is stored in the auxiliary cylinder, and is also let into the piston
cylinder. The valve Q being moved by piston valve K so as to connect port G
with port H, through the medium of recess k, air from the brake cylinder will be
allowed to exhaust through the latter port. The function of spring R is to cushion
the outward throw of the piston and prevent it from being injured by striking
head S, and another function is to afford a gentle resistance to the outward
movement of the piston, as I have found by experience that a better graduation
and control of the piston can be had when a spring is used in this position, although
in some cases the spring may be dispensed with.

page_text: For a service stop, in applying the brakes, the pressure is reduced in the line pipe
so as to bring port or passage over port or passage G and in this movement the
piston valve will be carried in advance of holes h, when the air will be carried from
the storage cylinder through passages C and D, into the interior of cylinder A and
from thence to the brake cylinder.
For an emergency stop, the pressure in the line pipe would be so reduced as to
carry the exhaust valve Qentirely past the large port or passage G, so that this
port will be brought wholly in communication with the interior of the piston
cylinder, allowing a larger volume of air to pass to the brake cylinder and apply the
brakes instantly.
While I have described specifically and in detail the various parts of my device,
yet I do not wish to be understood as limiting myself to the precise construction
and combination of devices shown, as I am aware that many of the parts might
be altered in form and arrangement without departing from the spirit of my
invention, and I therefore reserve the right to make such modifications and
changes as may fall within the scope of my invention.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is
1. In an air brake system, the combination with a brake cylinder and auxiliary
cylinder and a triple valve cylinder, of a valve casing communicating with the
triple valve cylinder and having a port for connection with the line pipe, a
reciprocatory valve arranged in said casing and having an upper and lower seat on
the inner side of the port or connection with the line pipe and also having a port
for communication with the auxiliary cylinder and a check valve arranged in this
latter port, substantially as specified.
2. The piston cylinder constructed as described in combination with the check
valve V, the piston valve the exhaust valve carried by the stem of the piston valve,
the third valve casing connected with the interior of the piston cylinder by a port
or passage and also connected with the port or passage of the cylinder carrying
check valve V, and having a check valve arranged in such port, and a third valve
actuated by the variable pressure in the line pipe and aided by a spring for
admitting air to the piston cylinder and auxiliary reservoir or cylinder, and also
allowing air from the piston cylinder to re-enter the line pipe, substantially as
specified.
3. In an air brake system, the valve casing, having a port or passage for connec-
tion with the line pipe, and also having two ports for connection with the piston
cylinder and auxiliary cylinder or reservoir, respectively, in combination with a
check valve arranged in one of said ports, the upper and lower valve seats in said
casing, the valve having the central enlargement adapted to engage said seats, and
also having a head at one end, and an adjustable spring surrounding the valve rod
or stem at its opposite end, substantially as specified.
4. The combination with the piston cylinder, substantially as described, of the valve
casing T, the bushings 4 and 5, arranged therein at opposite sides of the train pipe
port 2, and having the seats g¹ h', the bushing 5 having holes , the valve 3 having
channels m', and n', and a central enlargement 6 and also having the head at one
end and the opposite end threaded, the spring surrounding the stem within the
bushing 5, and the nuts on the threaded end of the stem for regulating the tension
of the spring, the whole adapted to operate and be attached to one end of the piston
cylinder, substantially as specified.
Dated this 7th day of November 1893.
W. P. THOMPSON & BOULT,
Agents for the Applicant.