IMPROVEMENTS IN GOVERNORS FOR OBTAINING UNIFORM ROTATION
Year: 1867

page_text: PROVISIONAL SPECIFICATION left by William John Macquorn Rankine
at the Office of the Commissioners of Patents, with his Petition, on the
7th November 1867.
I, WILLIAM JOHN MACQUORN RANKINE, of the University of Glasgow,
Professor of Civil Engineering and Mechanics, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN GOVERNORS FOR OBTAINING UNIFORM
ROTATION," to be as follows:-
This Invention consists of improvements on the instruments commonly
called governors, in which a load and the centrifugal force of a revolving mass
or masses act in opposition to each other, so that as one or other of their
forces preponderates the arm or arms carrying the revolving mass or masses
shift their position in one direction or the other so as to act on the motive
power by means of a regulating valve or other suitable apparatus.
The defect of the ordinary governor is that the speed of rotation at which
the balance between load and centrifugal force takes place varies with the-
position of the arms. In order that such balance may take place at one
uniform speed only for a given load the load is made to act upon a lever. or
levers so connected with the arms carrying the revolving masses that during
any change of position the levers acted upon by the load move through double.
the angle that is moved through by the arms. carrying the revolving masses..
The speed at which the balance of load and centrifugal force takes place can
be varied at will by altering the load, but not otherwise; the load may consist
either of a weight or weights, which must be distinct from the revolving masses.
which exert centrifugal force or of the elasticity of a spring.

page_text: In one arrangement for carrying the Invention into effect two rods with
balls at their four ends are jointed at their middles to a vertical spindle so as
to be capable of moving about the joint in vertical planes passing through the
spindle; two short levers are jointed to the spindle at a point the distance of
which below the joint of the ball rods is equal to the length of those short
levers, and their ends are fitted to slide upon the lower parts of the ball rods,
with which disposition of the parts it follows that the short levers must always
move through double the angle moved through by the ball rods. The rods
with the balls are balanced as regards gravity, but are free to assume different
positions under the influence of centrifugal force. If the load to oppose cen-
trifugal force is to be obtained by means of a weight such weight may be in
the form of a ring concentric with the spindle and freely suspended by links
or otherwise to any convenient parts of the short levers, or the load may be
produced wholly or partly by a weight adjustable on a lever acting on a collar
on the spindle, such collar being connected to the short levers. If the load is
to be obtained by means of springs these may be helical springs applied
between points on the short levers and a point on the spindle, all equidistant
from the joint of the short levers on the spindle. When springs are used for
applying the load the governor spindle may be placed in a vertical, horizontal,
or other convenient position.