Improvements in Indicators for Air Brakes of Railway Cars.
Year: 1890

page_text: Da's of Application, 11th June, 1890--Accepted, 12th July, 1890
COMPLETE SPECIFICATION.
Improvements in Indicators for Air Brakes of Railway Cars.
I HERBERT JOHN HADDAN of the firm of Herbert & Co. Patent Agents of
No. 18 Buckingham Street, Strand W.C. London in the County of Middlesex Civil
Engineer do hereby declare the nature of this invention a communication to me from
abroad by Patrick Henry Griffin of Buffalo, in the County of Erie and State of New
York, United States of America, Manufacturer, and in what manner the same is
to be performed to be particularly described and ascertained in and by the following
statement:-
:-
This invention has general reference to improvements in indicators for the air-
brakes of railway-cars, the same being adapted to show at a glance the position
which the piston of said air-brake occupied when the brakes were last applied, and
thereby indicate the available movement of said piston or the brake-power left, if any,
at the time of inspection of the brakes.
It is a well known fact that when the brake-shoes of a car are somewhat worn,
or the rods have stretched, owing to the tensil stress to which they are subjected, or
the bolts or the bolt-holes have worn, there is a possibility of such a car losing its
entire brake-power, notwithstanding the fact that the brake mechanism may apparently
be in perfect order, and the brakes properly operating when the engineer applies the
same, because the piston may travel its full length and strike the forward cylinder-
head and the brake-shoes will not touch the wheels or bear upon the same with
sufficient force to apply sufficient brake-power to stop the train.
Serious accidents have happened because trains were not under the control of the
brakes though the engineer had apparently applied the same.
As now in vogue
the engineer, when coupling his engine to the train, applies the brakes and then the
cylinders are inspected. But should one or more of them be found to bave their
piston travel beyond a certain limit, there is seldom time enough left before starting
the train to make the necessary repairs, while at any other time, except when the
brakes are applied it is impossible to ascertain the exact maximal movement of the
piston.
It is the object of this invention to show at all times the maximum travel of the
said brake-piston; and to attain this result 1 provide each brake-cylinder with an
indicator which will be moved by the said brake-piston whenever the brakes are applied,
but will retain its position when the brakes are released so as to show how far the
piston had moved when last applied.
To carry this invention into effect, I may use one or the other of a series of devices,
as illustrated in the accompanying sheet of drawings in which figure 1 is a side, and
fig. 2 a longitudinal sectional view of the brake indicator. Fig. 3 and 4 are a front
respectively a rear view of the same. Fig. 5 is a side elevation of a brake-cylinder
having a modified form of the indicator attached. Fig. 6 is a longitudinal sectional
elevation of the brake-cylinder provided with the indicator as a permanent fixture.
Like parts are designated by corresponding letters of reference in all the figures.
A is the car body to which the brake-cylinder B is affixed in the usual manner.
C is the brake-piston and D the piston rod. E is the forward cylinder-head having
the tubular piston-rod guide F, these parts constituting the usual brake-motor.
G is a metallic rod of suitable length having in one or both of its sides division
marks H, from 1 to 12 (being inches of the English scale) and indicating the full
stroke of the piston of the air brakes.
I is a socket having an angular aperture G₁, fig. 3, through which the rod G passes.
Within this socket there is a recess J, to receive a spring K, which, bearing upon the
said rod retains the same by frictional contact in any position into which it is put.

page_text: On the rod G there is a stop 9, entering a recess g¹ in the socket I which prevents the
rod from being entirely withdrawn from said socket.
In the device shown in figs. 1 and 6, the rod G penetrates the cylinder-head E and
entering the cylinder B is brought in contact with the piston (so that when the
brakes are applied and the piston C moved outwardly, the rod G will travel with said
piston, but when the latter recedes, (when the air from the cylinder is released by the
action of the spring E, fig. 6) the said rod G will remain in the position into which
it was moved and thereby indicate by the numerical marks H in inches the exact
distance which said piston has travelled when applying the brakes.
When constructing the brake apparatus, the socket I may be cast directly on to
the cylinder-head, such a construction being shown in fig. 6, but when applying the
device to brakes in use, the desired result may be obtained by either forming on the
socket I a screw-threaded shank I as shown in figs. 1 and 2, and by screwing this
shank into the cylinder-head, or by fastening the socket in any suitable manner to the
cylinder-head, as illustrated in fig. 5, and by forming a book G", on the rod G which
hook is engaged by the fork D' on the piston rod D and moves the rod G in the
socket in precisely the same manner as heretofore described with reference to the
device illustrated in figs. 1 and 6, the latter method of construction being somewhat
preferable for the reason that the cylinder-head need not be interfered with and that
the rod G does not enter the cylinder B. Other similar devices having intermittently-
operating disc or pointer moved by the brake-mechanism may be constructed to
accomplish the desired result in a manner more or less satisfactorily without departing
from the nature of the invention.
It will now be readily observed that this indicator, showing at all times the maximum
movement of the brake-piston, an inspection of the indicator-rod will always indicate
the exact condition of the brake-power of a car and adjustments, when necessary, can
be made no matter where the car may be at the time of inspection. When adjust-
'ment has been made in the brake-mechanism affecting the position of the brake-
piston it is necessary to move the indicator-bar G back to the starting point or at least
to a position indicating from 4 to 7 inches of piston travel, a matter which will be
evident from the nature of the case.
This invention is of the utmost importance in railway-brake-equipments and when
applied to a train will be a safeguard against accidents happening from insufficient
action of the brakes caused by the piston striking against the forward cylinder-
head.
'
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. An air-brake indicator moved by the brake-mechanism in one direction only,
whereby the maximum movement of the brake-mechanism may be ascertained in a
manner as set forth and described.
2. In combination with the brake-mechanism, an indicator for showing the maximum
movement of the brake-mechanism, said indicator being moved by the brake-
mechanism in one direction only and provided with a friction-device for retaining the
indicator in position, as set forth.
3. An air-brake indicator consisting, essentially, of a graduated rod, a socket, and
a friction-device, as set forth, said rod being moved by the brake-mechanism, as and
for the purpose set forth.
4. In an air-brake-indicator, the combination, with the cylinder-head, of a fixed
socket, a friction device within said socket, and a graduated rod passing through said
socket and having the hook, substantially as and for the purpose stated.
HERBERT & Co.,
18, Buckingham Street, Strand, W.C., London, Agents to Applicant.