IMPROVEMENTS IN STEAM ENGINES
Year: 1868

page_text: LETTERS PATENT to Andrew Masson, of Edinburgh, in the County
of Mid Lothian, North Britain, Engineer, for the Invention of
"IMPROVEMENTS IN STEAM ENGINES."
Scaled the 1st June 1869, and dated the 5th December 1868.
PROVISIONAL SPECIFICATION left by the said Andrew Masson at the
Office of the Commissioners of Patents, with his Petition, on the
5th December 1868.
I, ANDREW MASSON, of Edinburgh, in the County of Mid Lothian,
North Britain, Engineer, do hereby declare the nature of the said
Invention of "IMPROVEMENTS IN STEAM ENGINES," to be as follows, that is
to say :-
This Invention, which relates to improvements in apparatus or
mechanism for governing the cut off or admission of steam to the steam
chests of steam engines by means of double beat or equilibrium valves,
consists as follows:-On the shaft or spindle which carries the valve
a lever is placed situated outside the valve box or chest; to this a
vertical catch lever is applied, the catch lever being acted upon by
a spiral or other spring or by a weight in place of a spring. Beneath

page_text: the catch lever a suitable sliding bar is placed, this being driven from
the rocking shaft or ordinary eccentric rod of the engine by means
of a connecting rod driving a toothed quadrant which actuates a toothed
pinion fixed to the axis of a lever to which a corresponding vibrating
movement is thus communicated from the rocking shaft; or in place
of employing toothed or friction gearing for imparting the necessary
vibrating movements to the vibrating lever a double bell crank may
be employed. The vibrating lever is coupled to the vertically sliding
bar by a connecting rod, so that the bar reciprocates upwards and
downwards, and is in so doing acts upon the catch lever, as herein-before
described. The lever acted upon by the ordinary steam engine governor
is coupled by a gab rod to an adjustable vertically suspended lever. At
right angles to the vertically suspended lever a short lever with a
gile pin is fixed, so that as the vertically suspended lever is pushed
forwards or drawn backwards by means of the action of the governor
at the same time the lever carrying the guide pin at its extremity is
lifted upwards or depressed downwards. The side of the catch lever
is inclined or curved and bears against the guide pin accordingly as
the vertically sliding bar lifts the catch lever. The inclined or curved
side bearing against the guide pin causes the lower extremity of the
catch lever to be thrown out of contact with the vertically sliding bar
according to the position of the guide pin, and directly the contact
is broken the valve falls and the cut off of the steam is effected at
the part of the stroke required by the governor. The apparatus herein-
before described is by preference fixed to a bracket cast on the chest
or box which contains the double beat or equilibrium valve, but it
may be fixed otherwise as found convenient..
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Andrew Masson in the Great Seal Patent Office on
the 4th June 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ANDREW
MASSON, of Edinburgh, in the County of Mid Lothian, North Britain,
Engincer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eifth day of December, in the year.

page_text: of our Lord One thousand eight hundred and sixty-eight, in the thirty-
second year of Her reign, did, for Herself, Her. heirs and successors,
give and grant unto me, the said Andrew Masson, Her special licence
that I, the said Andrew Masson, my executors,. administrators, and
assigns, or such others: as I,. the said Andrew Masson, my executors,
administrators, and assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, usc, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN STEAM
ENGINES," upon the condition (amongst others) that I, the said Andrew.
Masson, my executors or administrators,. by an instrument in writing
under my, or their, or one of their hands and seals, should particularly.
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months. next and
immediately. after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Andrew Masson, do hereby declare
the nature of my said 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 accom-
panying Drawings, that is to say: —
My said Invention relates to meclianism whereby the ordinary or
other suitable governor is made to act on a double beat or equilibrium
valve so as to vary the durations of the admissions of steam to the
steam or valve chest of a steam engine. The movement for opening
the equilibrium valve is derived from the crank shaft or other con-
veniently moving part of the engine, and is transmitted through a
catch lever or intermediate piece, herein-after termed the catch, which
whilst moving in the direction to open the valve is also made to move
laterally by the action of an incline or its equivalent until it escapes
off the end of the bar acting on it, whereupon it allows the valve to
close, the valve always opening again at the commencement of the
succeeding stroke. The part acting on the incline is shifted by the
governor, so that the escape takes place at a later or carlier period in
accordance with the action of the governor.
And in order that my said Invention and the manner of performing.
the same may be properly understood I have hereunto appended a

page_text: Sheet of explanatory Drawings to be herein-after referred to and repre-
senting a modification of my improved mechanism as applied to a
horizontal cylinder steam engine, Figure 1 being a vertical section,
and Figure 2 a side elevation showing the equilibrium valve and its
actuating mechanism, whilst Figure 3 is a side elevation drawn to a
smaller scale and showing the parts in connection with the steam
cylinder.
The equilibrium or double beat valve 1 is lifted by a lever 2 fixed on a
horizontal spindle 3 which passes out through a stuffing box 4 and has
fixed upon it externally a horizontal lever 5. The external valve lever 5
has jointed upon it at or near its outer end a catch 6, the upper end
of which is pushed outwards by a spiral spring 7 carried by the lever 5.
The bottom end of the catch 6 is acted upon by a pair of bars 5 which
slide vertically in a guide formed for them in a bracket casting 9, and
which are connected by links 10 to opposite arms of a double bell crank
or three-armed lever 11. carried on a pin on the same casting. The
third arm of the lever 11 is actuated by a rod 12 from the valve
rocking shaft 13, and whilst this lever 11 is thus made to oscillate
backward and forward for every revolution of the crank shaft it produces
two upward movements of the catch 6, one of the bars 8 rising as
it swings to the right hand and the other as it swings to the left hand,
and the valve 1 is consequently always opened when the piston is at
either end of the cylinder. The catch 6 has an incline 14 formed at
one side of it, and as the parts rise this incline moves in contact with
guide pin 15 carried by a small sliding block 16, and is by it made to
move laterally as it rises until it escapes off the top of the bar 8. When
the catch 6 escapes in that way the valve 1 instantly closes by its
weight afterwards on the bar 8 descending below the bottom end
of the catch 6 the spring 7 causes that catch to resume its position
upon the top of it. It will be obvious that the period of the escape
of the catch 6 and consequent closing of the valve 1 will depend on
the position of the guide pin 15, and that on this being made suitably
adjustable by the ordinary or other convenient governor the durations
of the admissions of steam will be varied so as to maintain the engine
at a practically uniform rate under all ordinary circumstances. The
sliding block 16 carrying the guide pin 15 is moved up and down by
means of a bell-crank lever 17 which is connected with the governor
by a rod 18. The various details are obviously susceptible of con-
22

page_text: siderable modification; thus, for example, instead of the spring 7 the
catch may be formed with a weighted arm to press it towards the
guide pin 15, also the incline 14 may be curved instead of straight as
shown, also the necessary reciprocating motion may be imparted to
the bars 8 or to a single bar by a toothed quadrant actuating a pinion
on the axis of a lever connected to the bar. The bracket casting 9
carrying the various parts of my improved mechanism is by preference
bolted to a flange or bracket 19 cast on the side of the chest 20
containing the valve 1.
Having thus particularly described my said Invention, and the manner
in which the same is to be performed, I have to state that what I
believe to be novel and original and claim as the Invention secured
to me by the herein-before in part recited Letters Patent is, the using
of improved mechanism, substantially such as is herein-before described,
for applying the action of a steam engine governor in combination
with a double beat or equilibrium valve so as to vary the durations
of the admissions of steam.
In witness whereof, I, the said Andrew Masson, have here-
unto set my hand and seal, this Second day of Junc, in the