AN IMPROVED GOVERNOR FOR STEAM- ENGINES
Year: 1881

page_text: LETTERS PATENT to John Marshall Gorham, of No. 22, New Road, Lincoln,
England, for an Invention of "AN IMPROVED GOVERNOR FOR STEAM-
ENGINES."
COMPLETE SPECIFICATION filed by the said John Marshall Gorham at the
Office of the Commissioners of Patents on the 20th June 1881.
JOHN MARSHALL GORHAM, of 22, New Road, Lincoln, England, Engineer.
IMPROVED GOVERNOR FOR STEAM ENGINES."
My Invention relates to an improved form of governor for steam engines, so
constructed that the centrifugal force of the revolving balls or weights is counter-
balanced by means of weights or springs in any position of their sphere of action
and at any given speed of rotation. By a simple arrangement of the arms the balls
are made as they expand or fly outwards to exert an increased power over the
valve as it closes, and by restraining or controlling this power by means of weights
or springs to any desired extent, or until the tendency to fly outwards, due to
centrifugal force, is balanced by the springs, and the resistance offered by the closing
valve, a very sensitive governor is produced, responding instantly to any alteration
of load, and producing very even running in the engine, no increase in the speed of
the engine from the time the valve begins to act until the time that it completely
closes is necessary, and the centrifugal and centripetal forces transmitted to the
governor when caused to run above or below its normal rate of speed on account of
irregularities in the load of the engine, are utilized almost entirely in overcoming
the resistance offered by the valve.
A reference to the annexed Drawing will enable my improvements to be better
understood.
Let A, A, Fig. 1, be the revolving balls or weights; B, B, their range of action;
C, C, the restraining springs, one on each side of the governor; then if the balls be
in the position shewn when the engine is running.at its normal speed, any increase
in speed will cause the balls to fly to their extreme limit D, D, and completely
close the valve at once, since the power of the governor becomes greater as the
valve closes, but as the power of the restraining springs increases in the same

page_text: proportion, and together with the resistance of the valve counterbalances the
centrifugal force of the balls, the valve is reopened as soon as the normal speed of
the engine is restored. In the form of governor shewn in Fig. 2, an arrangement
in very general use (which will enable me to explain my improvements still more
clearly), when the normal speed of the engine is exceeded, the balls will fly
further apart, but will not completely close the valve until a sufficient speed has
been attained to force them to their extreme limit, as shewn by the dotted lines, a
higher speed being necessary than when they began to act. In the improved form
described above a greater regularity of speed is obtained, and a prompt and
immediate action upon the valve. I obtain these two advantages, 1st, by arranging
the arms and balls in such a manner that the distance or leverage E, Fig. 1, is
increased when the balls fly apart, that is, the distance between the plane of
gyration of the fulcrums F, F, and the plane of gyration of the balls or weights G, G,
measured in a line parallel with the governor spindle H, H, and perpendicular to
these planes is increased when the balls fly apart, as shewn at E, the reverse being
the case in the governor in general use, as shewn at E', Fig. 2; 2nd, by applying
the spring or springs C, C, to restrain and regulate the centrifugal force at all
points, and I also get an advantage by my arrangement of the governor arms,
because as the balls fly apart the arms are thrown more in a straight line (they can
if desired form a straight line at the utmost of their limit), and in this position the
thrust of the valve has very little influence upon the centrifugal force of the
governor, this being important because the thrust varies with the pressure in the
boiler, which is not constant in practice, and since the thrust increases as the valvo
closes and the balls fly apart, my governor meets this difficulty in not being unduly
influenced by a varying thrust.
Fig. 1 (dotted lines) shews the position of the governor when the valve is exerting
its greatest thrust.
Motion may be communicated to the equilibrium or other valve-spindle K by
any suitable means, as for instance, through two spindles I, I, attached to the
cross bar J.
Having now described my Invention, and the best means with which I am
acquainted for carrying the same into effect, I would have it understood that I do
not confine myself to the precise details, as described and shewn in the Drawing,
since they may be varied to suit circumstances without departing from the
character of the Invention, but what I claim as the peculiar feature of my
Invention is,
1st. That the valve is instantly and completely closed upon any alteration of
load taking place, and this closing is effected without any increased speed in the
engine being needful after the closing action has commenced.
2nd. The arrangement by which the arms in expanding tend to assume a straight
line with the governor spindle, thus placing them in the position of greatest
mechanical advantage for resisting the thrust of the valve when closing.
In witness whereof, I, the said John Marshall Gorham, have hicreto set my
hand and seal, this Seventeenth day of June, in the year of our Lord One
thousand eight hundred and eighty one.
Witness,
FRANCIS M. ROGERS,
Engineer,
21, Finsbury Pavt.,
London, E.C.
JOHN MARSHALL GOKHAM,
(L.S.)