CONSTRUCTION OF STEAM ENGINE INDICATORS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Sidney Moorhouso at the Office of the
Commissioners of Patents on the 25th June 1883.
SIDNEY MOORHOUSE of Stalybridge in the County of Lancaster
MENTS IN THE CONSTRUCTION OF STEAM ENGINE INDICATORS"
"IMPROVE-
This invention relates to the construction of Indicators for ascertaining the
power and quality of work performed by steam engines, and especially to that class
of indicators known as "Richards Indicators" wherein the cylinder carrying the
paper upon which the indication or diagram is to be taken is caused to oscillate
to-and-fro by a cord attached to a moving part of the steam engine and a spring
re-acting in the reverse direction; whilst the pencil is attached to a light parallel
motion in connection with a piston acted on by the steam.
According to my invention the pulley to which the cord is attached is mounted
and free to turn upon a fixed stud supported on the bracket or frame which carries
the apparatus. This pulley is provided at the top with a projecting rim or flange
on which fits loosely the lower end of a sleeve which carries the cylinder on which
the
paper is fixed.
The upper end of this sleeve turns upon the stud above named, so that the sleeve
(with the paper cylinder) and the pulley to which the cord is attached are
independent of each other excepting when the two are locked together as herein-
after described.
The spring box is fixed above the sleeve at the upper end of a tube attached to
or formed with the cord pulley.
Through a rim at the bottom of the sleeve on which the paper cylinder rests
I drill a hole into which locks a spring bolt carried by the cord pulley, so that the
two are locked together, and the to and fro movement of the pulley carries the
paper cylinder with it when the spring bolt is in its place.
In the same hole and with its end acting against the spring bolt I fit a loose
stud or pin, the outer end of which projects through the rim of the sleeve, in which
position it is held by the pressure of the spring bolt. So long therefore as this
loose stud is allowed to project, the spring bolt locks the paper cylinder and the
sleeve together, and the pulling of the cord attached to the pulley will cause the
paper cylinder to revolve, partially winding up the coiled spring: and as the cord

page_text: is released the reaction of the spring will give a reverse motion and cause the
pulley to wind up the slack of the cord.
Attached to the base or frame of the apparatus is a small detent provided with
a spring which has a constant tendency to hold the detent back and in connection
with this is a small cam on a spindle provided with a button or milled head.
When the detent is pressed forward by turning this cam by means of the button
or head, the detent carries the projecting end of the loose stud above mentioned,
and forces the spring bolt back until its end is level with the face of the rim on
the cord pulley, so that the latter can move to and fro without communicating any
movement to the sleeve carrying the cylinder; and there is a notch cut in the face
of the detent which catches the end of the loose stud and locks the sleeve and
cylinder fast, until the detent is released.
Thus it will be perceived that according to my invention only one coiled spring
is required, and that the sleeve, carrying the paper cylinder can be locked fast
either to the base or to the cord pulley, whilst the latter is constantly moving to
and fro and the cord is never allowed to get slack.
I also provide the paper cylinder with an additional spring clip for holding the
paper upon which the indication or diagram is taken.