A New or Improved Brake Piston Indicator for Railway Rolling Stock.
Year: 1891

page_text: Date of Application, 21st Apr., 1891
Complete Specification Left, 7th Aug., 1891-Accepted, 12th Sept., 1891
PROVISIONAL SPECIFICATION.
[Communicated from abroad by JOHN MCVEY BROWN, of Durban, in the Colony
of Natal, South Africa, Manager of the Carriage and Wagon Department,
Natal Government Railways.]
A New or Improved Brake Piston Indicator for Railway
Rolling Stock.
I, JOSEPH SINCLAIR FAIRFAX, of 433, Strand, London Consulting Engineer
and Patent Agent, do hereby declare the nature of this invention to be as
follows:-
:-
This invention, as communicated to me by my correspondent residing abroad, is
for a new or improved brake piston indicator, to be used in connection with the
continuous or other brakes employed upon railway rolling stock. The object of
the invention is to indicate, at sight, the travel, stroke, or position of the piston
within the brake cylinder; and also the wear of the brake shoes. The invention
may be applied to pressure, vacuum, or other forms of brakes in which brake
cylinders and pistons are employed.
In the further description of the invention, reference is made to the accompanying
drawings in which
Fig. 1 is a face elevation, Fig. 2 an end elevation, and Figs. 3 and 4 are detail
views of a brake piston indicating apparatus, as applied to an automatic vacuum
brake.
The brake cylinder A is mounted upon journals B, B, in bearings C, C, secured
to hangers D, D, which extend downward from the under frame E of the carriage
or other vehicle employed. The hangers D, D, are each formed with a boss at the
lower end, which are bored out to receive the ends or journals of a transverse
shaft F, carrying two fork-ended levers, G and H. The lever G is in the centre of
the transverse shaft F, and is adapted to receive the end of the piston rod 1. Any
stroke of the piston rod I is therefore communicated to the shaft F, by the lever G,
to put the brake on or off by means of suitable connections from the arm H to the
brakes. The journal ends of the shaft F are prolonged through the bosses of D, D,
to receive keys, or cottars J, J, or any other suitable fastening to secure the parts
in their relative positions. In addition to this there is also left at one end sufficient
room for two index fingers or pointers (with suitable washers) to be mounted upon
the outside of the hanger D. These pointers are so formed and arranged upon the
end of the shaft that the outer pointer K moves with the shaft F, whenever the
brakes are applied or taken off; and thus it may indicate the position of the piston
within the cylinder at any time. The outer pointer K is adapted to pass over the
face of the inner pointer L, which is loose on the shaft F, but a stud or other
projection M is secured or formed upon the outer pointer K which engages with
the edge of the inner pointer L, and carries the same with it, when the brake is
applied. On releasing the brake, the outer pointer K returns to its original
position, but leaving behind it the pointer L at the extreme point to which it was
previously carried. It will be seen, therefore, that the position of the inner
pointer L will indicate the travel or stroke of the piston within the cylinder, and
if the brake shoe or connecting pins become worn, to an undue extent, the piston
must travel further (making a longer stroke) with respect to the cylinder, and as
it does so the pointer L being carried further, to a corresponding extent, its position
at once indicates that the parts require re-adjustment.
In order to prevent the inner pointer L moving from the position to which it
may be carried by the outer pointer, and also to mark the exact amount of the
piston's travel, a segmental scale N is attached to the hanger D and marked in

page_text: inches or other desired units of measurement. The inner pointer L is preferably
made of steel, and with a spring action causing it to lay close to the scale, but in
addition to this a detent O is formed upon it near the point, and this engages with
ratchet teeth P, P. These are set in a direction to prevent a return of the
pointer L except when it is desired to return it to zero, when the brake is in good 5
order. As the outer pointer K always returns to zero when the brake is off, the
pointer L will also indicate by its position if a brake has been fully put on, in case
of an accident.
Dated this 20th day of Anvil 1901
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
A New or Improved Brake Piston Indicator for Railway
Rolling Stock.
I, JOSEPH SINCLAIR FAIRFAX, of 433, Strand, London, Consulting Engineer
and Patent Agent, 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 as communicated to me by my correspondent residing abroad, is
for a new or improved brake piston indicator, to be used in connection with the
continuous or other brakes employed upon railway rolling stock. The object of
the invention is to indicate, at sight, the travel, stroke, or position of the piston
within the brake cylinder, and also the wear of the brake shoes. The invention
may be applied to pressure, vacuum, or other forms of brakes in which brake
cylinders and pistons are employed.
In the further description of the invention, reference is made to the drawings
accompanying the Provisional Specification, in which
Fig. 1 is a face clevation, Fig. 2 an end elevation, and Figs. 3 and 4 are detail
views of a brake piston indicating apparatus as applied to an automatic vacuum
brake.
The brake cylinder A is mounted upon journals B, B, in bearings C, C, secured
to hangers D, D, which extend downward from the under frame E of the carriage
or other vehicle employed. The haugers D, D, are each formed with a boss at the
lower end, which are bored out to receive the ends or journals of a transverse
shaft F. carrying two fork-ended levers, G and H. The lever G is in the centre of
the transverse shaft F, and is adapted to receive the end of the piston rod I. Any
stroke of the piston and piston rod I is therefore communicated to the shaft F, by
the lever G, to put the brake on or off by means of suitable connections from the
arm H to the brakes. The journal ends of the shaft F are prolonged through the
bosses of D, D, to receive keys, or cottars J, J, or any other suitable fastening to
secure the parts in their relative positions. In addition to this, there is also left
at one end sufficient room for two index fingers or pointers (with suitable washers)
to be mounted upon the outside of the hanger D.
These pointers are so formed and arranged upon the end of the shaft, that the
outer pointer K, moves with the shaft F, whenever the brakes are applied or taken
off; and thus it will indicate the position of the piston within the cylinder at any
time. The outer pointer K is adapted to pass over the face of the inner pointer L
which is loose on the shaft F, but a stud or other projection M is secured or formed
upon the outer pointer K which engages with the edge of the inner pointer L and
carries the same with it, when the brake is applied. On releasing the brake, the
outer pointer K returns to its original position, but leaving behind it the pointer L
at the extreme point to which it was previously carried. It will be seen, therefore,
that the position of the inner pointer L will indicate the travel or stroke of the
piston within the cylinder, and if the brake shoe, or connecting pins become worn,

page_text: to an undue extent, the piston must travel further (making a longer stroke) with
respect to the cylinder, and as it does so, the pointer L being carried further, to
a corresponding extent, its position at once indicates that the parts require
re-adjustment.
In order to prevent the inner pointer L moving from the position to which it
may be carried by the outer pointer, and also to mark the exact amount of the
pistons travel, a segmental scale N is attached to the hanger D and marked in
inches or other desired units of measurement. The inner pointer L is preferably
made of steel, and with a spring action causing it to lay close to the scale, but in
addition to this a detent O is formed upon it near the point, and this engages with
ratchet teeth P, P. These are set in a direction to prevent a return of the
pointer L except when it is desired to return it to zero, when the brake is in good
order. As the outer pointer K always returns to zero when the brake is off, the
pointer L will also indicate by its position if a brake has been fully put on, in case
of an accident.
In applying the invention care must be taken to permit free movement to the
pointer L, so that when it is carried to any point it will not be forced back by
frictional contact on the return stroke of the piston when the outer pointer K
returns to zero. To effectually prevent this a slight projection should be turned
on the inner face of the eye of the pointer K, the projection being made a little
greater than the thickness of the inner pointer L, and the eye of the latter bored
out to fit easily on the same, so that when the pointer K is secured upon the
shaft A, the two pointers will not be so locked together as to prevent independent
movement in the manner indicated.
The brake indicator is readily applied to other forms of brakes-such as the
Westinghouse brake-in which the piston moves horizontally. The segmental
scale N is suitably attached to the panel or other convenient part of the carriage,
and the connecting levers correspondingly arranged to suit the said position.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
:-
1. A brake piston indicator connected to a brake piston and travelling therewith
to indicate the full stroke of the said piston and remain thereat on the return of
the piston, substantially as and for the purpose herein shown and described.
2. The combination of a shaft F working in bearings and suitably connected to
a brake piston, an arm or pointer K secured to the said shaft, a loose spring
pointer L on the same shaft carried forward from zero by contact with the
pointer K, and a scale N notched to retain the spring pointer L at the extreme
point of its travel, substantially as and for the purpose herein shown and described.
Dated this 6th day of August 1891.
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicant.