IMPROVED APPARATUS FOR REGULATING THE SPEED OF STEAM ENGINES
Year: 1871

page_text: LETTERS PATENT to John Duncan Gauldie, of Glasgow, in the County
of Lanark, North Britain, Engineer, for the Invention of "IMPROVED
APPARATUS FOR REGULATING THE SPEED OF STEAM ENGINES.”
Sealed the 24th May 1872, and dated the 29th November 1871.
PROVISIONAL SPECIFICATION left by the said John Duncan Gauldie
at the Office of the Commissioners of Patents, with his Petition,
on the 29th November 1871.
I, JOHN DUNCAN GAULDIE, of Glasgow, in the County of Lanark,
North Britain, Engineer, do hereby declare the nature of the said In-
vention for "IMPROVED APPARATUS FOR REGULATING THE SPEED OF STEAM
ENGINES," to be as follows, that is to say :-
This Invention has for its object to apply extremely simple and con-
venient means for regulating the speed of a steam engine; and consists
in connecting a shifting cut-off eccentric with a weight placed at a

page_text: distance from the revolving shaft in a radial direction, the same as or
parallel to that in which the eccentric shifts. A spring is applied to
tend to move the weight towards the shaft, but when the shaft revolves
the consequent centrifugal force gives the weight a tendency to move.
away from the shaft. If the proper speed is exceeded the weight over-
comes the spring, and by shifting the eccentric causes the steam to
be cut off earlier in each stroke. The eccentric acts on a cut-off or
expansion valve, which may be arranged in any of the ways common
to such valves.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Duncan Gauldie in the Great Seal Patent
Office on the 28th May 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
DUNCAN GAULDIE, of Glasgow, in the County of Lanark, North Britain,
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of November, in the
year of our Lord One thousand eight hundred and seventy-one, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Duncan Gauldie, Her special
licence that I, the said John Duncan Gauldie, my executors, adminis-
trators, and assigns, or such others as I, the said John Duncan Gauldie,
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,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVED APPARATUS FOR REGULATING THE SPEED OF STEAM ENGINES," upon
the condition (amongst others) that I, the said John Duncan Gauldie,
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

page_text: kind, which gives the steam access to the cylinder ports by passages
formed through it, and which is worked by an eccentric 8 permanently
fixed on the shaft 1, its position relatively to the shifting eccentric 2 being
indicated by dotted lines in Figure 2. A pair of flattened surfaces 9 are
formed on opposite sides of the shaft 1 (one of which serves as a seat for
the key by which the fly wheel 10 is fixed on the shaft) to serve as guides
to the shifting eccentric 2, which is formed with a slot or opening 11 to fit
and shift to a limited extent upon the shaft 1. The shifting eccentric 2 is
connected by means of a bent arm 12 to the weight 3, the weight having
fixed in it a screwed spindle 13, which passes through an eye in the end
of the arm 12, and is fixed by screw nuts on each side, by means of which
nuts the pressure of the spring, and consequently the speed of the engine,
may be adjusted. The weight 3 is fitted so that it can move radially in
a recess formed for it in the rim of the fly wheel 10, being additionally
guided by the inner end of the spindle 13, working in a socket formed
for it in the boss of the fly wheel. A helical steel spring 14 is applied
on the weight 3, its outer end bearing on the inside of the rim of the fly
wheel 10, and its inner end bearing against a flange formed on the inner
end of the weight, so that it tends to move the weight towards the shaft,
whilst the weight is maintained by the centrifugal force in a position
depending on the speed at which the shaft revolves. When, as in this
example, the main valve 7 is set to cut off at three-fourths of the stroke,
I arrange the shifting eccentric 2 in such a way that in shifting its
centre moves in a line 15-16, shown in the diagram, Figure 3, and
which forms an angle of about thirty degrees of the circle with the line
passing through the centre of the shaft 1 and the centre of the crank
pin 17, and which cuts the latter line at the same distance from the
centre of the shaft 1 as that of the centre 18 of the common eccentric 8.
The two extreme positions of the shifting eccentric 2 are shown by
dotted circles 19, 20.
Having thus particularly described my said Invention and the manner
of performing the same, I have to state that I do not restrict myself to
the precise details herein described or delineated; but 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 combining of a
revolving weight movable outwards by centrifugal force, and inwards by

page_text: valve, such combination being effected substantially in the improved and
direct manner herein described and delineated.
In witness whereof, I, the said John Duncan Gauldie, have here-
unto set my hand and seal, this Twenty-seventh day of May, in
the year of our Lord One thousand eight hundred and seventy-
two.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
JOHN D. GAULDIE. (L.S.)