Year: 1886

page_text: Date of Application, 27th Apr., 1886.
Complete Left, 22nd Jan., 1887.
Complete Accepted, 22nd Feb., 1887.
1, JOHN BUCHANAN, of 75 Robertson Street, Glasgow, Lanarkshire, Indicator
Maker, do hereby declare the nature of my invention to be as follows :—
The object of this invention is to obviate the great difficulty which is experienced
in keeping the small working pistons and cylinders of steam engine indicators
sufficiently fluid pressure tight consistent with the freedom and delicacy of action
necessary in such instruments. This difficulty is due to the irregular expansion of
these parts caused by the great variation in the pressure and temperature of the
steam now used in high speed triple expansion engines and to the difficulty of
efficiently lubricating the working surfaces of these instruments as at present
constructed. These steam engine indicators are also now used for gas, hot air, and
other motive power engines, to and for which my improvements are equally advan-
tageous.
The nature and novelty of my invention consist in making the cylindrical piston of
the indicator with a solid bottom, but of an open hollow cup shape above to contain
oil or other lubricant. The central steel spindle is secured at its lower end to the
solid bottom of the piston and projects up through the centre of the hollow cup part
and the pressure spring as usual, its upper end passing out through the screwed top
of the cylinder case and screwed to the indicating lever mechanism. The lower end
of the spring is now directly screwed to a short screwed stem and stop shoulder or
collar on the lower end of the central spindle within the cup, and projects up above
the upper open end of the piston for the purpose, the upper end of the spring being
as usual screwed to the inner side of the said top cover of the cylinder case.
piston is further formed with one, two or more shallow cut grooves round its outer
working cylinder, through each of which grcoves two or more very small holes would
The

page_text: be bored into the oil cup within, these holes being equally divided round the cylinder,
so as to pass the oil or other lubricant through from the inside of the cup at different
paris to lubricate the working surface of the piston and its cylinder nearly equally all
round. For filling the cup within the piston with the oil or other lubricant, one or
more small holes would be bored through the hollow swivelling eye of the arm
carrying the fulcrums of the indicating lever mechanism, or it might be through the
case just below the swivelling eye, or down through the top screw cover, so as to be
able to insert the short conducting tube of a small feeding filler, when desired, to fill
the cup of the piston inside its cylinder with oil just before going to take a diagram
to indicate the engine, without requiring to unscrew any of the parts. These oil
fillers would be made and supplied with the instruments all of the proper sizes to fit
the holes and direct the proper quantity of oil into the cup of the piston at each
time.

page_text: COMPLETE SPECIFICATION.
Improvements in Indicators for Steam and other Fluid-pressure
Motive Power Engines.
I, JOHN BUCHANAN, of 75 Robertson Street, Glasgow, Lanarkshire, Indicator
Maker, do hereby declare the nature of my 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, reference being had to the accompany sheet of Drawings, and
to the letters and figures marked thereon, that is to say :-
The object of this Invention is to obviate the great difficulty which is experienced
in keeping the small working pistons and cylinders of steam engine indicators
sufficiently fluid pressure tight, consistent with the freedom and delicacy of action
necessary in such instruments. This difficulty is due to the irregular expansion of
these parts caused by the great variation in the pressure and temperature of the
steam now used in high speed triple expansion engines, and to the difficulty of
efficiently lubricating the working surfaces of these instruments as at present con-
structed. These steam engine indicators are also now used for gas, hot air, and other
motive power engines, to and for which my improvements are equally advantageous.
And in order that my said Invention, and the manner of performing or carrying
the same into effect or practice may be properly understood, I have hereunto appended
an explanatory sheet of Drawings, in which the same reference letters are used to
indicate corresponding parts in all the figures where shown. Figure 1 represents an
elevation, partly in section, of an indicator for steam and other fluid-pressure engines,
having the improvements of my invention applied thereto. Figure 2 represents a
vertical section and a front elevation respectively showing my new or improved
construction of piston A secured to its piston rod A2 and Figure 3 represents a
vertical section of the filler used for charging or supplying oil or other lubricant to
the piston A a without withdrawing the latter from the cylinder B, or interfering
with the working of the indicator.
Referring to these Drawings:-the nature and novelty of my invention consist in
making the cylindrical piston A of the indicator cylinder B Figure 1 with a solid
bottom A and of an open hollow cup shape a above to contain oil or other lubricant,
as particularly seen in Figure 2. The central steel spindle A² is secured at its lower
end to the solid bottom A¹ of the piston A, and projects up through the centre of the
hollow part a and the pressure spring C as usual, its upper end passing out
through h the screwed top B' of the cylinder case B, and screwed to the indicating
lever mechanism, at d, in a usual manner, as shown in Figure 1. The lower end of
the spring is now directly screwed to a short screwed stem and stop shoulder or
collar c on the lower end of the central spindle A2, and projects up above the upper
open end of the piston A for the purpose; the upper end of the spring C being as
usual screwed to the inner side of the said top cover B¹ of the cylinder case B. The
piston A is further formed with one, two or more shallow cut grooves a' round its

page_text: outer working circumference through each of which grooves a two or more very
small holes are bored into the oil cup a within the piston A; these holes ² being
equally divided round the cylinder or piston A, so as to pass the oil or other lubricant
out through from the inside of the cup a into the grooves a at different parts to
lubricate the working surface of the piston A and the cylinder B of the indicator nearly
equally all round. For filling the cup a within the piston A with the oil or other
lubricant, an oblong hole (but it might be two or more small holes) is bored through
the hollow eye of the swivelling bracket D carrying the fulcrums of the indicating
lever mechanism, and a similar hole is bored or cut opposite it through the upper case
of the cylinder B, or it might be through the case just below the swivelling eye, or
down through the top screw cover B. (although not so shown in the Drawings,) so as
to be able to insert the short conducting tube e of a small feeding filler E, (shown in
vertical section in Figure 3) through the hole b, when desired, to fill the cup a of the
piston A inside of the cylinder B with oil just before going to take a diagram to
indicate the engine, without requiring to unscrew any of the parts. These oil
fillers Ee would be made and supplied with the instruments having their ends e of
the proper sizes to fit the holes and direct the proper quantity of oil into the cup a
of the piston A at each time. A small tap or plug may be fitted in the bottom of the
filler E to regulate the quantity of the oil supplied at each time. Although my
improvements have only been shown and described as applied to an ordinary Richard's
Indicator, it will be understood that they are equally applicable to all spring piston
indicators enclosed within their working cases and cylinders, such as those indicating
the pressures by a pointer, and a division plate on the case, over the pistons.
Having thus described and ascertained the nature of my said invention, and in whai
manner the same is to be performed, I declare that what I claim is :—
First. In indicators for steam and other fluid-pressure motive power engines, the
making of their pistons of a hollow cup shape for retaining oil or other lubricant, and
provided with holes and grooves a, a, substantially as and for the purposes herein
described, in reference to and shown in the accompanying Drawings.
Second. In indicators for steam and other fluid-pressure motive power engines, the
charging or supplying of oil or other lubricant to the piston through holes in the
casing of the indicator cylinder by means of a filler, substantially as herein described
in reference to and shown in the accompanying Drawings.