IMPROVEMENTS IN AUTOMATIC RAILWAY BRAKES AND IN TRAIN SIGNALLING APPLIANCES
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by Gerald Wenzeslaus von Nawrocki at
the Office of the Commissioners of Patents on the 27th May 1879. (A com-
munication from Robert Schultz, also known as Robert Niborn, of Kattowitz,
in the German Empire.)
GERARD WENZESLAUS VON NAWROCKI, of the Firm of J. Brandt and G. W. v.
Nawrocki, of 124, Leipzigerstrasse, Berlin, in the German Empire, Patents Agents.
"IMPROVEMENTS IN AUTOMATIC RAILWAY BRAKES AND IN TRAIN SIGNALLING
APPLIANCES." (A communication from Robert Schultz, also known as Robert
Niborn, of Kattowitz, in the German Empire.)
The object of this train signalling and automatic brake system for railway
carriages is to do away with the evil heretofore inherent in most brake systems,
viz., that the brake actuating power proceeds from the locomotive.
By this Invention, however, the acting power compressed air is produced and
acts automatically on each carriage by means of a small air pump. This pump is
arranged below on the waggon frame and with its downward projecting piston rod
vertically over one of the carriage axles, and by the turning of the latter the air
pump is kept going until the accumulated compressed air has a certain pressure,
when it is automatically thrown out of action.
Below the air pump the axle carries an eccentric of cast iron or oak; its double
eccentricity is slightly less than the greatest possible piston stroke. On the
eccentric rest two iron plates, one from each side, which terminate in a gripping
bar with guides.
Only in the highest and lowest position of the eccentric the gripping bars come
short for a small space, otherwise they leave a cleft or space between, which is so
wide that the lower thinner piston rod end of the air pump can pass easily between.
The head of the piston rod fits in a groove in the eccentric, and carries two cams
or catches which reach nearly the whole width of the eccentric; they are half
round above so as to slide easily under the other half round shaped gripping bars of
the eccentric. When these cams come to the open space under the gripping bars,
the air pump piston will by the turning of the axle and eccentric be drawn down and
pushed up. The air pump suction valve will open by the descent of the piston,
and the delivery valve open by the ascent of the piston; the compressed air is
forced into a reservoir, the lower part of which by pipes communicates with a
regulator adjoining the air pump; this regulator contains a weighted piston slide;
in the state of rest when this piston rests on its seat ring, a port leading from the

page_text: lower part of the regulator to the lower part of the air pump, is closed, but a
port leading from the upper part of the regulator to the upper part of the air
pump is open. There is also a communication between the upper part of the
regulator and the lower part of the air pump by a pipe, which, however, inside the
regulator by a spring valve is so closed that only air from the pump can enter
the regulator, but not vice versa.
When so much air has been forced into the reservoir that a certain pressure
has been created so as to overcome the weight of the slide piston and its friction,
the piston will rise and shut the upper port; by further ascent the air will be more
and more compressed and offer resistance.
The piston will at last be forced up so far that the lower port will be
opened.
The compressed air will then pass under the air pump piston, forcing it up,
the compressed air which may be above it escaping into the air, because the slide
piston at the same time opens the lower port, and the upper port communicates
with an opening to the air.
In consequence of the pressure under the pump piston, the piston rod head will
be forced out of the gripping bars of the eccentric when in turning it arrives at
that part where they come short.
The air pump will then be thrown out of gear. As the pressure in the reser-
voir decreases again the slide piston of the regulator descends into its lowest
position.
When thus the upper port is opened again the air under the pump piston will
pass above it and by reason of the greater area depress it. The piston rod head
and catches will then pass under the gripping bars. In this way the air pump is
put into motion again and the action described repeated.
To prevent dust and grit from entering the pump, the stuffing box packing is as
much inside as possible, and the whole may be enclosed in a casing.
The power stored up and available at any time during the running of the
carriage may be utilized both for signalling from passengers to officials, and between
the latter, and for actuating the brakes. For this purpose a pipe from the reser-
voir leads over the carriage and has at the end a shrill bell whistle like a steam
whistle, the compressed air being admitted by lever and cord appliances accessible
to the passengers.
To work the brakes a small brake cylinder is used, fastened between two axles
under the carriage frame; the piston rods passing out at each end are connected
to the brake levers.
A slide valve box with piston slide is connected by two pipes leading to each
end of the cylinder.
To actuate the brakes automatically the slide valve rod is connected to the
fixed part of the screw coupling between the carriages, so that as long as the
coupling is horizontal and in tension, the slide valve is in its forward position and
the brakes off. When the carriages run hard against each other the coupling drops
the slide valve, is moved back, and the brakes are put on.