IMPROVEMENTS IN THE GOVERNORS OF STEAM AND OTHER MOTIVE-POWER ENGINES
Year: 1867

page_text: LETTERS PATENT to Charles Louis Hett, of Bolton, in the County of
Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN THE
GOVERNORS OF STEAM AND OTHER MOTIVE-POWER ENGINES."
Sealed the 31st March 1868, and dated the 7th November 1867.
PROVISIONAL SPECIFICATION left by the said Charles Louis Hett at
the Office of the Commissioners of Patents, with his Petition, on the
7th November 1867.
I, CHARLES LOUIS HETT, of Bolton, in the County of Lancaster, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN THE GOVERNORS OF STEAM AND OTHER MOTIVE-POWER ENGINES," to be as
follows:-
This Invention relates to centrifugal or ball governors, and it consists in
so connecting the suspension rods and links to the vertical shaft that the parts
of the balls as they expand form an approximate parabolic curve instead of
the arc of a circle, and consequently the sliding bush and rod connected to
the throttle valve or cut off gear is moved to the required extent with the
slightest variation in the speed of the engine to be governed.
In performing my Invention I connect the suspension rods of the balls to
a stud passing through a slot in the vertical shaft and the sliding bush and rod
for actuating the throttle or other valve, or the cut off gear is connected to
this stud. The links jointed to the suspension rods are also jointed to a cross
head fixed to the vertical shaft; by this arrangement as the balls expand or

page_text: contract the upper ends of the suspension rods and the sliding bush and rod
connected to the throttle valve or cut off gear rise and fall according to the
position of the balls.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Louis Hett in the Great Seal Patent Office on the
5th May 1868.
.'
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
LOUIS HETT, of Bolton, in the County of Lancaster, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of November, in the year of our Lord
'One thousand eight hundred and sixty-seven, in the Thirty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Charles Louis Hett, Her special license that I, the said Charles Louis
Hett, my executors, administrators, and assigns, or such others as I, the
said Charles Louis Hett, my executors, administrators, and assigns, should
at any time agree with and no others, from time to time and at all times there-
after 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 "IMPROVE-
MENTS IN THE GOVERNORS OF STEAM AND OTHER MOTIVE-POWER ENGINES," upon the
condition (amongst others) that I, the said Charles Louis Hett, 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 Charles Louis Hett, 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 (that is to say) :-
This Invention relates to centrifugal or ball governors, and it consists in so
connecting the suspension rods and links to the vertical shaft that the path
of the balls as they expand form an approximate parabolic curve instead of
the arc of a circle as usual, and consequently the sliding bush and rod

page_text: connected to the throttle valve or cut off gear is moved to the required
extent with the slightest variation in the speed of the engine to be governed.
And in order that my Invention may be fully understood, and readily
carried into operation, I will proceed to describe the accompanying Sheet of
Drawings, reference being had to the figures and letters marked thereon.
In Figure 1 the balls a of my improved governor receive their support
from the bottom brass b through the links c, c, and d, d. This arrangement
together with a proper proportion in the lengths of the links cause the balls a
to move in an approximate parabola; and therefore the governor is nearly
isochronous. When the balls expand the pin e and the top brass or sliding
bush (carrying the ornament g with it) slide down the spindle h, returning
again when the balls collapse. This motion may be communicated to the
throttle valve or cut off gear by the rod i proceeding upwards and attached to
the pin e, or to the ornament g, as shewn in the Drawing. To allow the
governor to go at its proper speed the weight of the stretching weight i', the
top brass f, the ornament g, and the upper parts of the links d, d, must be
balanced by the counterweight 1 fixed to the rod m, suspended to the elbow
lever n which is connected by the rod o to the elbow lever P, the horizontal
arm of which is jointed to the top of the rod i; on this rod is fixed the
stretching weight, the object of which is to keep the rod o tight. The
rod m is connected to the throttle valve or cut off gear as usual. To prevent
the top brass f moving too much at once it is made to do duty as an air
cylinder, the spindle h if hollow being plugged at the top and the top brass f
grooved to make it practically air-tight on the spindle. A small hole if
necessary is made in the top of the ornament g to allow the air to enter and
escape. The increase or diminution of pressure in the top brass when the
balls change their position prevents their moving too far at once.
I wish to
observe that the air cylinder may be independent of the top brass, or an oil
cylinder may be used in lieu of an air cylinder.
The proportions I have adopted and which have been found to give good
results in practice are as follows, but I do not limit myself to these or any
other proportions:-The short links c are one-fourth of the length of the long
links d. The distance between the centre e to the junction of the links c and
d is equal to three-eighths of the length of the links d. The distance between
the centres at the bottom of the links c, c, is equal to seven twenty-sixths of
the length of the links d. The vertical distance between a line passing
through the bottom of the centres of the links c, c, and the centre e when the
balls are full out is six-thirteenths of the length of the links d. The travel
of the slide or top brass f is equal to seven fifty-secondths of the length of the

page_text: links d, as shewn by the dotted horizontal lines f¹, and the curved and
diagonal lines x, y, and z, indicate the curve and limits of the range of the
balls.
the
In Figure 21 have shewn a modification of my improved governor ;
parts marked a, b, c, d, e, f, and 9, are made as in the governor above
described; but the spindle h is hollow to allow the rod i to pass downwards
from the pin e to the forked lever p on the short shaft q, at the extremity of
which is fixed the lever r, to which the rod m is jointed. The lever p is pro-
longed for the counter weight 1. The rod m is connected to the throttle valve
or cut off gear.
Having thus stated the nature of my Invention, and described the manner
of performing the same, I declare that I claim,-
First. The arrangement of links, by which the centres of the balls are caused
to move in an approximate parabola.
And secondly. The use of the slide or top brass as an air cylinder in con-
junction with the above arrangement of links.
In witness whereof, I, the said Charles Louis Hett, have hereto set
my hand and seal, this Twenty-ninth day of April, One thousand eight
hundred and sixty-eight.
CHARLES L. HETT. (L.S.)