Improvements in Air-pressure Brakes for Railways.
Year: 1892

page_text: Date of Application, 18th Feb., 1892
Complete Specification Left, 18th Nov., 1892-Accepted, 21st Jan., 1893
PROVISIONAL SPECIFICATION.
Improvements in Air-pressure Brakes for Railways.
I THOMAS HUMPHREY, of Hurstville, near Sydney, New South Wales, Engineer,
do hereby declare the nature of this invention to be as follows:-
This invention relates, firstly; to means for graduating off railway brakes
operated by air pressure, secondly; giving the driver an accurate knowledge of the
varying pressures in the brake cylinder, and thirdly; to be able to release and again
apply the brake two or more times in succession on any vehicle detached from the
main source of supply.
The first of these objects is effected by the combination of a pressure registering
and graduating off valve, and a constant pressure reservoir, all of which would
work in connection with the usual main reservoir train-pipe, small reservoir, and
brake cylinder.
The pressure registering and graduating off valve consists of three cylinders
connected together, two small of same size, and one larger between the two smaller
ones. In these cylinders work four pistons three small ones and one large one;
two small ones above the large one act as valves to admit and release pressure from
the small reservoir. The constant pressure reservoir is kept in constant communi-
cation with the top side of large piston: these reservoirs are supplied with pressure
from the main train-pipe and retained by back acting valve. The underside of
large cylinder is placed in communication with the pressure from the main pipe
when the pressure is turned on. In the upper small cylinder is an inlet for pressure
from small reservoir and outlet to brake cylinder, and exhaust for same, controlled
by piston valves.
The pressure from top small cylinder is also conducted down to lower small
cylinder, the pressure being assisted by spiral spring acting on bottom of piston.
The releasing valve is an ordinary three way cock placed in the pipe connecting
the small top cylinder with the brake cylinder. It is operated by a pivoted lever,
one end of which receives motion from a small piston and cylinder in communication
with the train pipe pressure, and the other end moved by hand to effect the release
of pressure from brake cylinder.
Dated this 18th day of February 1892.
FREDERIC PRINCE,
Agent for Applicant.
COMPLETE SPECIFICATION.
Improvements in Air-pressure Brakes for Railways.
I THOMAS HUMPHREY of Hurstville near Sydney New South Wales 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 firstly to means for graduating off railway brakes operated
by air pressure. Secondly giving the driver an accurate knowledge of the varying
pressures in the brake cylinder; and thirdly to be able to release and again apply
the brake two or more times in succession on any vehicle detached from the main
source of supply.
To enable this invention to be properly understood I will proceed to describe the
same with aid of the accompanying drawings.
Figure 1 side elevation of my invention complete

page_text: Figure 2 a larger view of a part shown in Figure 1.
Figures 3 and 4 sectional modifications.
Figure 5 detached sectional view of part shown in Figure 1.
The first of these objects is effected by the combination of a pressure registering
and graduating valve arrangement G and a constant pressure reservoir F all of
which work in connection with the usual main reservoir A, train pipe B small
reservoir D, and brake cylinder E.
The pressure registering and graduating off valve G consists of three
cylinders K, K, K', connected together, two small of same size, K¹ and K2 and a
larger one K between the two smaller ones.
In these cylinders work four pistons L, M, N, O; three small ones and one
large one; the two small ones L M, above the large one N act as valves to admit
and release pressure from the small reservoir D through pipe Q and through
pipe T to brake cylinder E. The pressure of the constant pressure reservoir Fis
kept in constant communication with the top side of large piston N by pipe R.
These reservoirs are supplied with pressure from the main pipe B and retained by
back acting valve I. The underside of large cylinder K is placed in communication
with the pressure from the main pipe by the branch pipe U when the pressure is
turned on at C. In the upper small cylinder K' is an inlet for pressure from
reservoir D through pipe Q and an outlet communication with pipe T to brake
cylinder E and an exhaust S controlled by piston valve L. The pressure in top
small cy linder K¹ is also conducted down to lower small cylinder K2 by branch
pipe T and enters at T2 the pressure being assisted by spiral spring P acting on
bottom of piston O. The releasing valve to let off the pressure in brake cylinder E
is an ordinary three way cock-Figure 5-the plug a of which has the usual two
passages e and controlled by the lever f when plug is in the position shown in this
figure the pressure to brake cylinder E is open being normally so held by the
piston in small cylinder J, upon the cock being turned by pulling up the lever f
by the handle the pressure in brake cylinder E is released at e. The pressure in
small cylinder J is received from pipe B through branch pipe j. Figure 3 is a
modified arrangement of G or Figure 2. In this plan there is but one cylinder F1
of the same diameter throughout having two pistons Y. Z. connected by rod, the
pistons being held in a normal position by springs E and E' attached to the piston
rol is a lever B' pivotted at C' the outer end being connected to a valve D' with a
right angle way. As the pressure at top or bottom of pistons Y. Z. vary the
valve D is correspondingly moved. In this arrangement the pressure from
reservoir F comes in through pipe U₁ and from train pipe through pipe R, and
from reservoir D, through pipe T³.
Figure 4 is another modification of Figure 2. In this arrangement the valve J¹
on rod K is in place of the pistons L. M. and is controlled by the pressure acting
on top of piston H', or by variations of pressure in cylinder G'.
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
claim is
The construction of the valve arrangement G and the modifications thereof with
the various operating parts substantially as and for the purposes hereinbefore
described and illustrated by the accompanying drawings.
Dated this 18th day of November 1892.
:
FREDERIC PRINCE,
1, Quality Court, Chancery Lane, London, Agent for Applicant.