An Improved Brake for Narrow Gauge Railways, Steam Tramways, and the like.
Year: 1897

page_text: Date of Application, 15th Jan., 1897-Accepted, 20th Mar., 1897
COMPLETE SPECIFICATION.
An Improved Brake for Narrow Gauge Railways, Steam Tramways,
and the like.
I, WOLFGANG SCHMID of 26 Bayer Strasse Munich in the Empire of Germany,.
Railway 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 :-
It is well known that for narrow gauge railways, steam tramways and the like,
a simple and safe-acting continuous brake does not yet exist. The Heberlein
brake with a cord does not come into favour owing to its inconvenient application
by means of a brake-reel. The automatic vacuum brakes freeze in winter time.
The compressed air brakes with their numerous valves are too complicated and too
expensive in their maintenance for such cases. The non-automatic brakes are for
this kind of railway dangerous, because owing to the loud noise of the escaping
air, the horses of the vehicles are scared and run away.
Schmid's screw .brake with compressed air apparatus fulfils the purpose
perfectly, but its costs of construction are somewhat high for narrow gauge
railways.
To meet the requirements in such cases, where only the simplest but necessarily
automatically acting apparatus is best suited to be employed, I have constructed
an improved spring pressure brake, operated by compressed air or
vacuum
utilizing my already patented air chamber for actuating or regulating my screw
wheel brake.
These brakes are simple in their construction, have neither pistons which are
not tight, nor valves, pawls or slides. They consist merely of an air pot or
chamber and a spiral spring. In both cases, whether compressed air or vacuum
be employed, a flexible diaphragm piston is employed in the air chamber, which
never ceases to act because the flexible skin is perfectly tight. The spiral springs
are also thoroughly tested so that they last many years.
In the accompanying drawing,
Figure 1 shows a horizontal section; Figure 2 an elevation and Figure 3
a cross section of the spring pressure brake with compressed air operating device.
In Sheet II, Figure 1 is a horizontal section; Figure 2 an elevation and
Figure 3 a cross section of a spring pressure brake operated by vacuum; whilst
on Sheet III, Figure 4 shows a carriage fitted with a spring pressure brake
operated by compressed air, and Sheet IV, Figure 5, shows a similar carriage
or tramcar, in which a spring pressure brake is employed with a vacuum operating
apparatus.
Figure 1 shows the air chamber in section. The piston is here already pulled
to the left by means of a spiral spring b, which has forced the lever c to the left
and thus applied the brake. At the opposite end of the lever c at the point d the
brake drawbar is arranged, and by means of this bar or rod the brake blocks
are drawn against the carriage wheels. Figure 1 shows the air chamber a for
vacuum with a diaphragm piston a' as in the compressed air operating device.
The drawing shows here also the brake in a closed condition; the spring extended
forcing the piston to the right and applying the brake blocks to the wheels by
means of the lever c and brake rod.

page_text: Both brakes act automatically by means of the spiral springs.
The compressed air or vacuum is only employed in both cases to keep the brakes
off, so that if the compressed air be allowed to escape or the vacuum be destroyed
by the admission of air, the springs act on the brakes.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
A spring pressure brake operated by compressed air or vacuum, consisting of
an air chamber (a) having a flexible skin or diaphragm piston (a), suitably
connected with the brake regulating lever (c), and a spiral spring (b) adapted to
act on one side of said piston, the other side being exposed to the action of
compressed air or vacuum, substantially as herein before set forth.
WM. P. THOMPSON & Co.,
. Of 6 Lord Street, Liverpool, Agents for the Applicant.