Improvements in and relating to Air Pressure Brakes for Railway Vehicles.
Year: 1897

page_text: Date of Application, 18th Mar., 1897-Accepted, 10th July, 1897
COMPLETE SPECIFICATION.
Improvements in and relating to Air Pressure Brakes for Railway
Vehicles.
I, MICHAEL SCHLEIFER, of 56 Bulow Strasse Berlin in the German Empire
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:―
In long railway trains, for which the single chamber air pressure brakes are of
great value, there occur, especially on sudden application of the brake apparatus,
such jerks and breakages of the connections that the brakes act dangerously for
the rolling stock, and even the strength of the railway cars is not sufficient to resist
the destructive shocks.
One reason of the shocks referred to lies in the application of the process whereby
that portion of the tube air released from the tubes on the sudden application of
the brakes, is applied for the purpose of obtaining very rapid action by the sudden
increase above the normal full brake action, of the apparatus and for the purpose
of hastening the commencement of this action. Another reason is to be discovered
in the unsuitable construction of the controlling devices which have hitherto not
allowed of the regulation in a simple manner of the quickening of the initial
brake-action, and of the method of progressive increase up to the highest brake
power, in such manner that a breaking in two of long trains is rendered impossible.
The excessively powerful brake action produced especially by the application of
tube air as hereinafter explained takes place, in all methods hitherto known,
invariably first in the front part of the train, so that it becomes impossible to apply
the brakes to long trains suddenly without severe shocks.
The injurious shocks also inevitably increase with the amount of tube air
suddenly overflowing into the brake cylinder at the commencement of the braking,
and it therefore appears necessary to abandon the use of the same for the increase
of the brake power, unless a method can be discovered to guide and regulate this
liberated portion of the tube air by means of simple reliable mechanism that will
not increase the injurious initial shock.
The previous method of conducting and distributing the compressed air from
the auxiliary air reservoir to the brake cylinder, as well as the surcharging of the
compressed air in the brake cylinder, and the consequently resulting sudden strong
brake action taking place in the front part of the train which has been obtained by
the use of the triple valves hitherto known, is consequently entirely abandoned in
the present construction. For the construction of unobjectionable compressed air
brakes especially for long trains there is indispensably requisite according to the
researches of the inventor, the fulfilment of the following three principal
conditions:-
1. The brake power must be capable of being increased easily and certainly by
regular gradation consecutively up to the full efficiency by means of the consecutive
release of small quantities of compressed air from the tubes.
2. In the case of the sudden and most powerful application of the brakes the
brake power must commence as quickly as possible in all the brake cylinders of

page_text: the train, and increase in them all continuously up to the highest efficiency;
in the hinder part of the train moreover it must increase very rapidly in order that
the brake efficiency may considerably and permanently exceed that reached at the
front part of the train, so that the front portion will be extended and stretched
without a shock until it arrives at a full stop.
3. The locomotive must be braked exactly in the same manner as the tender
and cars.
These three main conditions which have hitherto never been attained in combina-
tion are satisfied by the present new invention of a special method of division of
the compressed air in various brake cylinders in the fore part and hinder part
of the train, and the new controlling device for air pressure brakes as hereinafter
set forth.
Referring to the accompanying drawings, in which
Figure 1A represents a train pipe, B a controlling valve, C a brake cylinder,
Dan air chamber, E an auxiliary air chamber, all suitably combined with one
another.
Figure 2 shews the controlling valve for the tender and cars, and
Figures 3, 4, and 5 shew diagrammatically the various positions thereof.
Figs. 67 and 8 illustrate the controlling valve for the locomotive.
-
The principal parts of the controlling valve shewn in Fig. 2 are as follows:-
A controlling piston 3 with spindle 11 having a double sleeve and fitting tightly
in its casing. A hollow slide valve 9 actuated by the spindle.
cut off valve 14 with the throttle valve 14¹.
A double sleeve auxiliary piston 12.
A shut-off valve 16.
A quickening valve 64.
The working of these parts is as follows:-
An inlet and
Charging of the brake.-The air penetrating from the main air tube into the
controlling valve at 1 (see Figure 2) fills the space 2 and forces the piston 3 to the
right. Hereby the connection 15 to the brake cylinder is cut off by the inlet valve 14,
supported by the spring 22, from the space 6 which stands in permanent
connection with the auxiliary air reservoir. The air then passes through the
channel 4 uncovered by the piston 3 into the surrounding channel 4 over the
sleeve 5 of the piston 3 in the space or auxiliary air chamber and charges
the same.
The valve 16 shuts off the tube connection 1 from the channel 13.
The space 20 below the piston 12 stands by means of a channel 19 in connection
with the space 6 or auxiliary air chamber and is filled at the same time as this.
The brake cylinder as well as the space 15 of the quickening valve (see Figure 3)
are then placed in contact with the free air through the channels 15+ and 152,
also the air chamber through the channel 18 and 18 by the action of the
slide valve 9 and the channels 10' and 10. The condition number 1 is thus
fulfilled.
Graduated application of the brake. The graduated application of the brake
is effected by repeated opening and closing of the main brake valve. If the main
brake valve be open and air let out of the main tube connection and space 2
(see Figure 2), then in consequence of the surplus pressure in space the piston 3
will move to the left and after the slide valve 9 has shut off the brake cylinder
channel 15, the valve 14 is opened (see Figure 4). On the closing however of the
main brake valve there occurs, through the rushing out of the auxiliary reservoir
air into the brake cylinder a surplus pressure upon the left side of the piston 3,
and this forces the same again to the right past the space 8. The inlet valve 14
is thereby closed by means of the spring 22 (Figure 2). Upon a further similar
delivery from space 2 there again occurs a small surplus pressure upon the right
side of the controlling piston 3, the inlet valve 14 opens itself again for a moment,
and the operation continues until gradually the maximum efficiency is reached in
the brake cylinder. In graduated braking (Figure 4) the air chamber remains in
connection with the outer air through the channel 18, 18¹, space 9, bore hole 10

page_text: notch 10 and channel 10. To the extent moreover that the pressure in the main
pipe is further diminished after the graduated braking has been continued up to
maximum efficiency, that is, after the pressure has been equalised between the
auxiliary air reservoir and the brake cylinder the surplus pressure existing in the
space 6 propels the controlling piston to its outermost position to the left (Figure 5).
The piston then carries the slide valve 9 so far with it that the channel 13 is
connected with the channel 18 through the slide valve 9. A portion of the air from
the connecting tube can consequently suddenly flow into the air chamber because
the valve 16 is opened through the surplus pressure in space 20 (Figure 2) or in
the auxiliary air chamber. In consequence of this, the indicator of the air
pressure gauge connected to the main tube and placed upon the locomotive
suddenly goes back, and thereby gives to the driver a certain indication that the
maximum efficiency of the brake is attained, and that any further discharge of air
from the main tube would be waste. This fulfils the second condition.
Sudden application of the brake (quick braking).--If the main brake valve is
suddenly opened to the full and this opening maintained so long that in the front
part of the main tube a great reduction of pressure can quickly result, a number
of the controlling pistons 3 in the front part of the train will be immediately
driven entirely to the left into their end position through the surplus pressure hereby
occasioned in the auxiliary air chamber, and the air can only pass slowly through
the small annular opening of the throttle valve 141 (Figure 5) into the brake
cylinder. In precisely the same moment there flows also a portion of the air out
of the main tube into the air chamber through the channels 13, 181, slide valve 9,
channel 101 18 on account of the valve 16 being opened by the surplus pressure in
the space 20 or auxiliary air chamber. Hereby a further diminution of all
pressure is created in the main tube. In consequence of the sudden reversal of the
controlling piston 3 from the right to the left end position, the compressed air in
the auxiliary air holder has only for a moment opportunity to pass into the
brake cylinder through the larger cross opening which is provided by the neck 23
of the throttle valve 14¹ to the channel 15. A braking effect is consequently not
hereby obtained, because the first entering compressed air is not able to move the
piston retained by the spring in the brake cylinder. In the next moment,
however, the throttle valve 141 cuts off already the entrance and the brake pressure
in the brake cylinder increases corresponding to the remaining fixed size of the
annular opening only slowly. The diminution of pressure which in the meantime
has reached the hinder part of the train and has become weaker is not able there
to create immediately a full and sudden reversal of the controlling pistons 3, but
the same remain in the middle position (Figure 4) and in consequence hereof
there is obtained through the larger opening into the hinder brake cylinders
obtained through the neck 23 of the throttle valve 14', a higher pressure more
quickly than in the front brake cylinders. After however the further decrease
of the pressure created in the air chambers through the escape from the main tube
has reached the hinder part, the controlling pistons are brought into their end
pesitions, and there now increases in this part the brake pressure in the brake
cylinders through the annular opening of the throttle valve. After the obtaining
of a certain pressure in the brake cylinder the quickening valve 6 (Figure 5)
which has been hitherto held closed by the pressure of the spring 63, will be opened
and the equalisation of the pressure in the auxiliary air chamber and the brake
cylinder is attained not only through the annular opening of the throttle valve 14',
but also through the channels 61, 62, 151, and thus produces the quick full brake
pressure first in the hinder part of the train, and then propagates it gradually
towards the front of the train.
For the realisation of the third preliminary condition the simplified controlling
valve shewn in Figures 6, 7, and 8 suffices. In this modification the pistons 12
as well as the cut off valve 16 for the conduction of the tube air into the air
chamber are done away with because here the air from the air tube passes directly

page_text: through the main brake valve controlled by the driver into the atmosphere. The
throttle valve 14' is also done away with because the controlling valve on the
locomotive is always at the front of the train and consequently has not, as in the
case of the cars to open a greater or lesser passage from the auxiliary air chamber
to the brake cylinder, according to the position of the car in the train. The action
in the graduated braking is exactly the same as in that of the controlling valve
already described. When the brakes are suddenly applied (quick braking) this
valve acts in such manner that the air from the auxiliary chamber passes slowly
into the brake cylinder after the opening of the inlet valve 14 through channel 15
small borings 155 by means of the space 15%, channel 151 (Figure 7). After the
attaining of a certain brake pressure in the brake cylinder which also
communicates itself to the space 153 above the quickening valve 64 which has been
hitherto held closed by the pressure of the spring 63 the latter is depressed or
opened (Figure 8). The equalisation of the pressure in the auxiliary air chamber
and the brake cylinder will consequently be attained not only through the hole 155
but also through the channel 15, open valve 6+, and space 15", channel 15¹
(Eigure 8) and thus cause the quick braking.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:
1. A controlling arrangement for single chamber air pressure brakes, which
when the air tube is widely opened for the purpose of immediate discharge of the
air therein, will nevertheless in a number of the front controlling valves effect
the commencement of an increased braking action in the brake cylinders of the
hinder part of long railway trains more quickly than in the previously first braked
front part of the train, and will also maintain this greater braking effect in the
hindpart of the train to its full effect, wherein the inlet and cut off valves with
throttle mechanism 14, 14' which are dependent upon the motions of the controlling
pistons 3 effect for the transfer of compressed air through the auxiliary air holder E
to the brake cylinder C in the case of the greatest motion of the controlling
pistons 3 a very small opening and in the case of smaller movements a maximum
opening whereby in both parts of the train these two channel sections are arranged
in such manner and remain open unaltered, so that the greater braking action in
the hind part of the train must already take place, before this can extend to the
front part, so that the whole train arrives at the stationary position in a stretched
out condition.
2. A modification of the controlling arrangement characterised in Claim 1 in
which, upon the sudden letting off of the pipe air necessary for the effecting of
the quick braking action and immediate holding fast of the controlling pistons
in the front part of the train forced over to their end position at each controlling
valve thereby limited, and at the gradual or graduated application of the brakes
the effecting of the highest efficiency will be indicated, that a slide valve 9
connected with the controlling pistons in its left end position (Figure 5) under
influence of a cut off mechanism 12, 16 in this moment opened by the auxiliary
air chamber and which valve is interposed between the main conduit and a closed
space D, enables the pressure from the conduit to pass over so suddenly and without
resistance into the space 1), that on the pressure gauge of the air conduit an
indication appears for the closing of the drivers brake valve.
3. A modification of the controlling device characterised in claim 1 in which
the inlet valve 14 provided with a spring and carried in the spindle 11 of the
controlling piston 3, is connected with the throttle valve 14' by means of a thinner
channel 23 of uniform or altering section and of such length that in all middle
positions which the controlling piston can assume after the commencement of its
motion up to against the left end position under the most various influences of
the degrees of pressure in long trains, a larger opening of the inlet valve 14
corresponding to the neck remains assured until reversal of the controlling piston,

page_text: and thereby the strong throttling of the air access results, which through the
length of the throttle piston 14 even in the case of reversed disturbance of the
controlling piston will not be destroyed by unintentional variations of the air
pressure in the conduit.
4. A modification of the controlling mechanism characterised in Claim 2, in
which the air chamber D limiting the flow of conductor air in the case of quick
braking, and graduated application of the brakes up to the commencement of the
maximum effect is held constantly in communication with the outer air and ready
to take up the tube air thereby that a notch 102 standing in connection with the
free air channel 10 is formed in the slide valve 9 and the closing of this notch only
occurs, after the slide upon the other side of the channel 13 is opened, which
connects the tube A through valve 16 and channels 13 and 18 with the air
clamber D.
5. A modification of the controlling arrangement characterised in Claim 1,
whereby a quickening of the commencement of the maximal effect in each brake
cylinder is thereby attained by that after the commencement of the stretching of
the train caused by the greater brake action in the hinder part thereof upon the
reaching of a certain pressure in each brake cylinder this pressure actuates a
quickening valve 6 which supports the inlet and throttle mechanism 14, 141
controlled by the controlling piston 3 in such a manner that the complete
equalisation between the air pressure in the auxiliary air container and the brake
cylinder suddenly results.
6. A modification of the controlling mechanism characterised in Claim 1 in
which for the actuating of the locomotive brakes the controlling piston 3 permits
compressed air to pass from the auxiliary air chamber through a little opening 155
to the brake cylinder ir. all positions which cause the shutting off of the locomotive
brake cylinder from the outer air, so that in the said cylinder the brake pressure
can only increase slowly up to a certain degree until the hinder part of the train
is stretched, then however by opening the quickening valve 6 must increase
suddenly up to the full efficiency in the brake cylinder.
1
101
1
C 30
1
10112
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester and Birmingham,
Patent Agents for the Applicant.