Improvements in Pneumatic Brake Apparatus for Railway Trains.
Year: 1889

page_text: Date of Application, 7th June, 1889
Complete Specification Left, 7th Mar., 1890-Accepted, 12th Apr., 1890
PROVISIONAL SPECIFICATION.
Improvements in Pneumatic Brake Apparatus for Railway Trains.
I, ADOLPHE WENGER, of 23 Boulevard de Strasbourg, Paris, France, Civil Engineer
do hereby declare the nature of this invention to be as follows:-
This invention relates chiefly to means of accelerating the action of pneumatic
brakes, to valve arrangements in the communications to the brake cylinders and to
the construction of the engineer's brake valve.
For accelerating the action of the brakes I provide on each brake carriage two air
reservoirs communicating with each other, with the train pipe and with the open air
through a special valve box, the former of the two reservoirs being always in com-
munication with the auxiliary reservoir belonging to the brake cylinder. In the
upper part of the special valve box works a piston with packing which allows air to
pass upwards but prevents air from passing down. This piston is supported by a
spring in the lower part of the valve box and the stem of the piston engages between
collars a slide valve governing ports leading respectively to the second reservoir and
to the outer air. The valve box under the piston communicates with the train pipe;
above the piston it communicates with the reservoir first mentioned, so that compressed
air from the train pipe pressing up the piston finds its way past the piston into the first
reservoir the second reservoir being at the same time kept by the slide valve in com-
munication with the open air. When the pressure in the train pipe is somewhat reduced,
the piston descends moving down the slide valve and thereby putting the second reservoir
in communication with the train pipe causing a reduction of pressure therein proportional
to the capacity of this reservoir, and thereupon compressed air from the first reservoir
passes by a small hole through the piston, reducing the pressure in the first
reservoir. The rapidity with which the pressure is thus reduced depends upon the
greater or less capacity of the second reservoir in relation to the capacity of the train
pipe and its communications, and by adjusting the area of the small hole through the
piston the rapidity of reduction of pressure for each brake may be regulated as desired.
A second valve box is interposed between the first reservoir and the auxiliary reservoir
and brake cylinder. In this valve box there is also a piston which is held between an
upper spring and a more powerful lower spring and which also works a slide valve
governing parts communicating respectively with the brake cylinder and with the
open air.
When the brake pipe is charged with compressed air, the pressure is raised
as already described in the first reservoir, and compressed air passing thence into the
second valve box under the piston raises the piston and its slide valve whereby air is
allowed to escape from the brake cylinder. At the same time compressed air passes
the piston packing into the auxiliary reservoir charging it, while the brake piston is
entirely relieved from pressure. When the pressure in the brake pipe is reduced, an
action takes place in the second valve box similar to that in the first valve box, that is
to say, the piston and slide valve are depressed, and compressed air passes from the
auxiliary reservoir into the brake cylinder causing the brakes to be put on, with a
rapidity and force depending on the greater or less capacity of the second reservoir
above mentioned and on the greater or less area of the escape hole from the first
reservoir. The pistons of the two valve boxes have leather packings which have thin
lips directed upwards and are pressed by washers subject to springs, so that, while
they permit passage of air upwards, they prevent return of air downwards, remaining
tight notwithstanding the dryness of the leather. In the second valve box the piston
does not directly work the slide valve which is held between a collar on the piston rod
below it and a sleeve sliding on the piston rod above it, this sleeve being subject to the
pressure of the upper spring. Thus, when the piston descends the slide valve also

page_text: descends but only so far as the sleeve, which meets a stop, permits, and there the slide
valve remains until the piston reascends to meet it and with pressure sufficient to
overcome the upper spring. For charging the brake pipe or varying the pressure
therein so as to operate the brakes I provide an engineer's brake valve or cock
consisting of a plug with passages through it rotatable within a casing which has four
ports communicating respectively with the supply pipe of compressed air, with a
discharge to the atmosphere with the train pipe and with a discharge reservoir of
capacity such that when the train pipe discharges into it there is sufficient reduction of
pressure to give movement to the pistons of the valve boxes first described. The plug
is turned by hand to such attitudes as to effect the desired communications between
these ports, whereby the brakes can be put on either gently or suddenly, by the slow
or the rapid reduction of the pressure in the train pipe, or the brakes can be taken off
by charging the train pipe with compressed air.
Dated this 7th day of June 1889.
ABEL & IMRAY,
Agents for the Applicant.
.
COMPLETE SPECIFICATION.
Improvements in Pneumatic Brake Apparatus for Railway Trains.
I, ADOLPHE WENGER of 23, Boulevard de Strasbourg, Paris, France, Civil Engineer
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 relates chiefly to means of accelerating the action of pneumatic
railway brakes, to valve arrangements in the communication to the brake cylinders
and to the construction of the engineer's brake valve, as will be described referring to
the accompanying drawings.
For accelerating the action of the brakes I provide apparatus such as is shewn in
plan Fig. 1, and in Fig. 2 to a larger scale in section on M N O P of Fig. 1, the other
Figs. 3, 4 and 5 being part sections hereinafter referred to.
A is a reservoir, Ba cylindrical valve box in which works a piston p urged
upwards by a light spring, and carrying with it as it moves a slide valve t. Another
reservoir the capacity of which is determined according to that of the air pipe of
each vehicle and to the desired reduction of pressure. The brake cylinder of the
vehicle is always in communication with the reservoir A, and the brake piston is subject
to the variations of pressure in A. The train pipe crosses the apparatus at D, whence
there is free passage e to the space below the piston p. By the pressure in the train
pipe D the piston p is raised, raising the slide t and allowing air to escape from C by
the port b the cavity of the slide t and a port d leading to the outer air. Also the air
from D passing the cup leather of the piston p, proceeds through the ports o o¹ and o³
to charge the reservoir A and by a channel M to the special reservoir R for the brake
cylinder. If now the pressure in the train pipe is somewhat reduced, enough to
overcome the force of the spring r, the piston p descends with the slide t which
uncovering the port b, allows a volume of air to pass from the train pipe to the
reservoir C proportioned to the capacity of this reservoir. Air from the reservoir A
also escapes by a small hole at a through the piston p until the pressure above and
below the piston is nearly equalised, whereupon the piston is raised by the spring r,
and the siidet, putting and d in communication, allows the air to escape from C,
thus restoring the conditions for a subsequent operation of the same kind. The small
hole a has no effect in effecting reduction of pressure in the train pipe, the rapidity of
this reduction depending on the ease with which the piston p is displaced and the
capacity of the reservoir C in relation to that of the train pipe. But the passage of
air through the hole a on each vehicle determines the rapidity with which the brakes
of that vehicle are applied, since it is the reduction. of pressure in the reservoir A
which causes the brakes to be put on. The reduction of pressure is propagated with

page_text: great rapidity along the train pipe by the use of the reservoir C, but by lessening the
port a the actual application of the brakes on each vehicle may be made slow and
gradual as desired.
Should the reduction of pressure in the train pipe be so small and so slow as not
to cause descent of the piston p, air would, nevertheless by passing slowly by the
port a from the reservoir A, cause moderate application of the brakes. Between the
reservoirs A and R is interposed a valve box E in which works a piston F. carrying
a slide valve G (Figs. 3, 4 and 5).
From M air can pass by H to the space under the piston F, J is a passage to the
brake cylinder with which the port e communicates by passage f. The port g leads
by a passage to the open air. Disregarding for a moment the springs L and N
applied to the piston, the operation would be as follows: Supposing that air at a
pressure of 50 in the train pipe D has passed through M and H and has raised the
piston F as shewn in Fig. 2. and that air passes its cup leather and by holes o³
enters the chamber containing the slide G, thence it passes by I into the reservoir R
charging it with compressed air, while the brake cylinder communicates with the
outer air by the passages Jf and ports eg h. On reducing the pressure in the
train pipe D, which, as above described causes reduction of pressure in M H, air
from R cannot pass the cup leather of F backwards, but it forces down the piston
shifting the slide G so that air now passes from R to the brake cylinder X causing
the brakes to be put on. The cup leather of F is held between collars by pressure
of a spring P, so that it remains tight even when the leather becomes dry.. Above
the piston F is a stop collar K and spring L, and below the piston is a much
stronger spring N. As the piston descends the collar K comes to rest as shewn
in Fig. 4 on a shoulder of the slide facing S thus relieving the piston from the
strain of the spring L when the slide completely closes the port e.
The piston
continues to descend compressing the spring N, until it meets the stop S¹ and then
the port e is quite open as shewn in Fig. 5. The piston is caused to ascend by the
spring N until the stop collar K is again raised from S the port e being then closed,
and now the spring L resists farther ascent of the piston, and if this resistance in
conjunction with the differential pressure on the piston is equivalent to the strain
of N, the piston will remain at rest and the port e will remain closed until additional
pressure comes to act under the piston, sufficient with the force of N to overcome
the force of L. The result of this arrangement is that the pressure acting in the
brake cylinder is proportioned to the reduction of pressure in the train pipe,
consequently the force of the brakes can be regulated at pleasure. When the train
pipe is re-charged to full pressure the piston F ascends raising the slide G so as
to put the brake cylinder by e and g in communication with the outer air, and
thereupon the brakes are taken off.
Fig. 6 is a section of the drivers brake cock. The casing has 4 passages, m opening
under the plug and supplying compressed air, n facing the plug and opening to
the air, u leading to the discharge reservoir, leading to the train pipe. When the
plug is in the position shewn which is that for taking off the brakes, compressed
air entering by m under the plug passes by the groove q to v charging the train
pipe, and the ports n and u are closed. On turning the plug so as to bring a small
hole to face v, the cavity y then facing n air is discharged slowly from the train
pipe by vxy and n, and the brakes are put on slowly and moderately, and then
on turning the plug about 45° either way, the brakes remain on. If however the
plug be turned about half round putting v in communication with u through y,
there is a rapid passage of air from the train pipe to the discharge reservoir which
is of suitable capacity to govern the extent to which the pressure in the train pipe
should be reduced in order to operate the pistons p (Fig. 2), and the brakes are
thus put hard on.
By discharging into a discharge reservoir there is less waste of compressed air
than if the discharge were to the atmosphere. On turning back the plug so as to
put u and n into communication by y the air from the discharge reservoir escapes
to the atmosphere, and everything is in condition for operating afresh. Instead of

page_text: allowing the air from the train pipe to escape freely at the engine, I prefer to
discharge it by a small orifice into a reservoir having a small outlet which can be
closed when it is desired to stop the discharge. This arrangement moderates the
excessive reduction of pressure which tends to result from the momentum of the
air in the train pipe, particularly on a long train.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In compressed air brake apparatus, a special reservoir and valve apparatus on
each brake vehicle, whereby a moderate reduction of pressure in the train pipe is
made to produce a much greater reduction in the communications with the valves for
operating the brake piston, substantially as described.
2. The valve apparatus above referred to, wherein a piston packed with cup leather
and provided with an escape hole is held up by a weak spring and moves a slide
valve arranged and operating substantially as above described.
3. The valve apparatus which governs the communications of the brake reservoir
and brake cylinder by means of a slide worked by a piston subject to the strains of
springs above and below it, acting in combination with stops, substantially as and for
the purpose set forth.
4. The construction of drivers brake cock, substantially as described with reference
to Fig. 6.
.ה .יני
1000
ABEL & IMRAY,
Agents for the Applicant.