IMPROVEMENTS IN AIR PRESSURE CYLINDERS FOR RAILWAY BRAKES AND OTHER PURPOSES
Year: 1885

page_text: I MICHAEL SCHLEIFER, Engineer at Berlin, Bütowstrasse, 29 do hereby declare
the nature of the said invention for "IMPROVEMENTS IN AIR PRESSURE CYLINDERS
" to be as follows:-
FOR RAILWAY BRAKES AND OTHER PURPOSES
The present improvements relate especially to the arrangement and the rendering
air tight of the cylinders used in air pressure brakes for railway carriages, but this
improvement may also be used in air-pressure-cylinders for other purposes.
In the cylinder specially intended for air-pressure brakes, the compressed air
which serves as usual to work the piston, is admitted by an opening at one end
of the cylinder, but the working pressure of the piston proceeds from the opposite
end thereof. In order to attain this without employing cocks, valves, canals or
grooves and at the same time to diminish the consumption of working-air in an
advantageous manner the following arrangement is made.
The cylinder is bored out for a little distance to a greater diameter, so that the
leather-ruffle or fitting of the piston does not lie against the inside of the cylinder;
and therefore when the piston is at the end of its stroke and reaches this enlarge-
ment, communication is established between the two parts of the cylinder before
and behind the piston, owing to the ring-shaped space thus made.
A small cone forms the connection of the enlarged part of the cylinder with the
other one. As soon as the piston (in consequence of the compressed air penetrating
through the opening at one end of the cylinder) has in its backward course
reaches the cone or enlarged space of the cylinder, this air escapes through the
space to the other side of the piston and continues doing so till the tension of the
air is equal on both sides. The piston remains in this position until the work
required of it, namely a motion in the contrary direction, has to take place. For
this purpose the air contained in the space behind the piston is suddenly allowed
to escape, whereupon the compressed air in the space in front of the piston, presses
the leather-ruffle or fitting against the inside of the cylinder and sets the piston in
motion. On the backward course of the piston, therefore on its moving in the first
named direction, the leather-ruffle fits close to the inside of the cylinder as long as
the piston has not reached the enlarged space, so that the full pressure of the
compressed air let in at one end of the cylinder operates on the piston and does not

page_text: begin to escape into a space on the other side of the piston to equalize the pressure
on both sides until the piston has reached the cone and the enlarged part of the
cylinder.
To avoid a one-sided wear of the cylinder, the piston or sliding rod is provided
with guides on both sides of the piston, of which the one consists of a closed
cylinder or sleeve whereas in the other the piston-rod passes through a stuffing-box
to be coupled to the moving parts placed outside the cylinder. The arrangement
for stuffing of the piston-rod is as follows: A leather-ruffle or fitting is screwed on
to a tie by means of a nut. This leather-ruffle therefore moves with the piston-rod
and is pressed by the air contained in the cylinder against the sides of the guides,
whereby the piston in whatever position it may be will work air tight.
In order to protect the piston-rod from dust and rust a felt disc is screwed on
and that part of the piston-rod which projects beyond the cylinder is enveloped in
a wrapper consisting of an elastic material. This pliable wrapper is connected at
one end with the stuffing box and at the other with the piston-rod, so that the last
named end can follow the motion of the piston-rod owing to the pliability of the
wrapper.
A modification of the above construction can be effected in such a manner that
the leather-ruffle does not move with the piston, but is fastened by a nut to the
cylinder-cover and the stuffing is then attained by the leather-ruffle pressing
against the piston-rod.
By these arrangements a sure and exact working of such air-pressure cylinders
will be obtained more perfectly than could be done in using cocks valves, channels
or grooves.

page_text: I, MICHAEL SCHLEIFER of Berlin in the German Empire, do hereby declare the
nature of my said invention for IMPROVEMENTS IN AIR PRESSURE CYLINDERS FOR
RAILWAY BRAKES AND OTHER PURPOSES and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
These improvements relate especially to the arrangement and the packing of the
cylinders more especially those used in air pressure brakes for railway carriages
but these improvements may also be used in air pressure cylinders for other
purposes.
In Figure 1 the new arrangement for air pressure brakes is represented.
In a cylinder specially intended for air pressure brakes the compressed air which
serves as usual to work the piston is to be admitted by an opening a at one end'
of the cylinder but the pressure for working the piston must proceed from the
opposite side.
In order to obtain this without employing cocks valves canals and grooves and
at the same time to diminish the consumtion of working air in an advantageous
way the following arrangement is made.
The cylinder is bored out for a slight distance b. to a greater diameter so that the
cup leather or leather fitting & of the piston does not lie against the inside of the
cylinder and therefore when the piston is at the end of its stroke in this enlarge-
ment there is communication between the two parts of the cylinder A. and B
before and behind the piston owing to the annular space thus formed.
A small cone e forms the connection of the enlarged part of the cylinder with
the other part. As soon as the piston has in consequence of the compressed air
passing through the opening a arrived at the cone e or enlarged space 6 of the
cylinder, this air escapes through the space c to the other side of the piston in the
chamber B and continues doing so till the tension of the air is equal on both sides
of the piston. The piston remains in this position until the work required of it,
namely a motion in the contrary direction has to take place. For this purpose the
air contained in the space A behind the piston is suddenly allowed to escape
whereupon the compressed air in the space B, before the piston begins to operate
presses the cup-leather against the inside of the cylinder and sets the piston in
motion. On the return movement of the piston therefore on its moving in the
direction of the arrow the cup leather or fitting fits close to the inside of the
cylinder as long as the piston has not reached the enlarged space C so that the full
pressure of the compressed air admitted at a operates on the piston and does not
begin to escape into the space B on the other side of the piston to equalize the
pressure on both sides until the piston has reached the cone e and the enlarged
part C of the cylinder.
To avoid one-sided wear of the cylinder the piston er sliding rod is provided
with guides on both sides of the piston of which the one, F, consists of a closed

page_text: cylinder whereas at the other end, F¹, the piston rod passes through a stuffing box
in order to be coupled to the moving parts placed outside the cylinder.
The packing of the piston may be arranged as follows:-
A cup leather is screwed on to a collar f by means of a nut m
This cup
leather therefore moves with the piston rod and is by the air contained in the
cylinder B forced against the sides of the guides C whereby tight working of the
piston in all positions is ensured.
In order to protect the piston-rod from dust and rust a felt disk h is screwed on
and the part of the piston rod projecting beyond the cylinder is enclosed in a
wrapper g. consisting of elastic material. This pliable wrapper is connected at the
one end with the stuffing box and at the other i with the piston or the slide rod
so that the end of the latter can follow the motion of the piston rod owing to the
pliability of the wrapper g.
A modification of the above construction can be effected (as represented in
Figure 2) in such a manner that the cup leather does not move with the piston but
is fastened by a nut m¹ to the cylinder-cover and the piston is caused to work
airtight by the pressure of the cup leather against the piston rod-By these
arrangements certain and exact working of such air pressure cylinders will be
obtained in a more satisfactory manner than when using cocks valves channels or
grooves.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed I declare that what
I claim is
1. In a cylinder, piston and packing for pneumatic brakes and the like the
annular space b connecting the two parts A and B of the cylinder in combination
with a piston K whereby air or other fluid under pressure admitted at a may be
enabled to exert pressure upon the opposite face of the piston without the inter-
vention of grooves channels valves taps or the like substantially as shewn and
specified.
2. In a cylinder and piston arrangement for pneumatic brakes and the like the
packing consisting of a cup leather 7 or the like fixed on the collar f by a nut m.
and pressed against the sides of the guide surfaces C in combination with
guides F F for the piston rod, a disc h of felt or the like and the elastic or flexible
hood fixed at i and serving as a protection against dust and rust substantially as
described and shewn in Figure 1.
3. The modification of the packing in which the cupleather is attached to the
cylinder cover and is pressed against the piston rod in combination with the
piston rod guides F, F¹, substantially as shown and described with reference to
Figure 2.
Dated this 90th
CT11002