Improvements in and relating to Indicators for Steam or other Fluid-pressure Engines.
Year: 1892

page_text: Date of Application, 14th Apr., 1892
Complete Specification Left, 12th Jan., 1893-Accepted, 18th Feb., 1893
PROVISIONAL SPECIFICATION.
Improvements in and relating to Indicators for Steam or other
Fluid-pressure Engines.
We, ROBERT MCKINNELL, Consulting Engineer, of 29 Waterloo Street, and
JOHN BUCHANAN, Indicator Maker, of 75 Robertson Street, both in Glasgow,
Lanarkshire, do hereby declare the nature of our invention to be as follows:-
This invention has reference to and comprises certain improvements in indicators
used for taking graphical diagrams of the power exerted in steam and other pressure-
fluid cylinder engines and specially applicable to the Richard's and other like
indicators.
These improvements consist in a more convenient mode and means of securing
the helical pressure or drawing springs over and outside the indicating cylinder,
instead of inside as heretofore in these indicators, and which will enable the
different scale springs employed to be more easily changed and secured than
hitherto, and be maintained at a more uniform temperature.
These improvements, as applied to a Richard's indicator, under one arrangement
consists in mounting a stationary crosshead over the indicating cylinder on two
standards projecting up
from snugs attached to opposite sides of the cylinder below
the revolving head, of the arms carrying the indicating pencil levers, and at a
sufficient height above these to allow them to swivel freely below the crosshead
and between the columns. This crosshead would have formed on it a central guide
bush or eye through which the upper prolonged end of the piston rod of the
indicating cylinder would pass, and have a screw neck on its upper face to which
the lower screwed end of the indicator removable spring would be secured while
the upper hollow screwed end of the spring would be secured to the extended upper
screwed end of the piston rod by a duplex thumb screw or nut screwing into the
spring and on to the screw end of the rod, all so that as the piston was moved up
or down by pressure of steam or vacuum in the indicating cylinder, the spring
would yield to that corresponding extent; and the piston rod would be made to
move the indicating levers by a double ring boss mounted on it, or by links
connecting the boss to the levers; in either case allowing the levers and their
swivelling head to as usual oscillate on the top of the cylinder to put the marking
pencil or pointer into or out of action on the indicating paper barrel rotated by
the cord from the engine.
Under another arrangement the swivelling head or frame mounted on the top
of the indicator cylinder, would have its arms carrying the indicating levers placed
radially and centrally as in the previous arrangement instead of to the side as
heretofore, and have the upper part of the web on opposite sides continued up
sufficiently above the centre of the cylinder to carry a guide screw bush on the top
in the axial line of the cylinder and piston rod, and have it open above the screw
top of the cylinder; and this screw bush would have the lower screw socket of the
spring screwed on to it. And further the piston rod would be lengthened and
fitted up through this screw bush and spring and sufficiently beyond them, with a
screw on its outer end to take into a screw wheel or lock nut which would be
secured on the outer screw socket end of the spring. A small collar boss would or
might be secured by a pin or otherwise to the piston rod, so as to rise and fall with
it between the cover of indicator cylinder and the lower screw bush of the spring,
according to the pressure or vacuum exerted below the piston; and the parallel
acting radial bars would in this case be mounted on opposite sides of the swivelling
bracket and collar boss at their extreme fulcrum ends by fixed or oscillating spindles
fitted in the arms of the swivel frame. While the adjacent ends of these bara

page_text: would be connected by their oscillating link carrying the indicating pencil or
pointer in the centre as usual, the upper bars having circular parts working between
the collars of the boss on the piston rod, and so be moved up or down by the
pressure acting on the indicator piston. Instead of connecting the radial bars by
a collar boss, as described, they might be connected by links to a swivelling boss
mounted loose between collars or shoulders on the piston rod.
This improved method or mode and means of fitting the helical springs round a
continuation of the piston rod above the cylinders of indicators, is also applicable
to those indicators with single scribing levers with the pencil or pointer at their
extreme ends; but in this case the levers would either require to be doubled and
worked as a duplex single lever on each side of the piston rod or work freely
through a slot in the continuation of the piston rod, and be connected by short
links to the piston rod to allow the pencil lever to oscillate on its radial parallel
motion levers and centres or segmental guides to cause the extreme free end of the
lever and pointer to work vertically in the axial line of the diagram cylinder.
And in the case of the single lever indicator which gives the parallel motion to
the pencil to suit its different angles by reciprocating through a swivelling eye or
sleeve, this sleeve would oscillate in a slot or gap in the continuation of the piston
rod. To permit of the free motion of these single levers carried on the hollow
swivelling boss at top of cylinder for bringing the point of the pencil to act against
the diagram cylinder, the lower screw guide boss of the piston rod and spring
would require to be carried on the top of two side frames projecting up from the
opposite sides of the hollow swivelling head on the cylinder, leaving free parallel
vertical space between them for the free reciprocating action of the pencil levers.
Dated the 13th April 1892.
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.
COMPLETE SPECIFICATION.
Improvements in and relating to Indicators for Steam or other
Fluid-pressure Engines.
We, ROBERT MCKINNELL, Consulting Engineer, of 29 Waterloo Street, and
JOHN BUCHANAN, Indicator Maker, of 75 Robertson Street, both of Glasgow,
Lanarkshire, do hereby declare the nature of our invention, and in what manner
the same is to be performed to be particularly described and ascertained in and
by the following statement in writing, that is to say :-
This invention has reference to and comprises certain improvements in indicators
used for taking graphical diagrams from which is calculated the power exerted in
steam and other pressure-fluid cylinder engines and specially applicable to the
Richard's and other like indicators.
These improvements consist in a more convenient mode and means of securing
the helical pressure drawing springs over and outside the indicating cylinders,
instead of inside as heretofore in these indicators, and which will enable the different.
scale springs employed to be more easily changed and secured than hitherto and
be maintained at a more uniform temperature.
And in order that our said invention and the manner of performing or carrying
the same into effect or practice may be properly understood we have hereunto
appended an explanatory sheet of drawings, representing an elevation and plan
respectively of a Richard's indicator as fitted with one arrangement of our
improvements.
Referring to these drawings:-The improvements consist in mounting a stationary
crosshead a over the indicator cylinder A on two standards a¹, a¹, projecting up
from snugs A¹, attached to opposite sides of the fixed cylinder base below the
revolving head A², of the central radial arms A", A", carrying the actuating
levers A, A, of the pencil lever A, and at a sufficient height above these to allow

page_text: them to swivel and oscillate freely below the crosshead a and between the
columns a¹ a when taking a diagram. This crosshead a is made to swivel on the
top of the standard a' and has formed on it a central guide bush or eye a² through
which the upper prolonged end of the piston rod B of the indicating cylinder A,
would pass and has a screw neck on its upper face to which the lower screwed
end of the indicator removable spring is secured; while the upper hollow
screwed end of the spring b is secured to the extended upper screwed end of the
piston rod B, by a duplex thumb screw or nut B' screwing into the screw end 62 of
the spring band on to the screw end B', of the rod B, all so that as the piston was
moved up or down by pressure of steam or vacuum in the indicating cylinder A,
the spring would yield to that corresponding extent; and the piston rod B would
be made to move the indicating levers A³, A*, by a double ring boss B³, mounted
on it or it might be by links connecting the boss to the levers; in either case
allowing the levers A, A, and their swivelling fulcrum brackets A" to as usual
oscillate on the top of the cylinder A, to put the marking pencil or pointer z into
or out of action on the indicator paper barrel Z, rotated by the cord Z¹ from the
engine. This mode and means of fitting the scale pressure helical springs of
indicators outside the cylinders, although only shown as applied to a Richard's
indicator it will be evident to engineers and indicator makers, is equally applicable
to other modifications and forms of engine indicators such as those with single
scribing levers.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
In indicators for steam or other fluid-pressure engines, the fitting and use of the
helical pressure springs outside the cylinders, substantially as and for the purposes
herein described in reference to and by way of application shown in the accom-
panying drawings.
Dated the 11th T1002
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents