IMPROVEMENTS IN CENTRIFUGAL GOVERNORS AND EXPANSION GEAR"
Year: 1883

page_text: LETTERS PATENT to Wilson Hartnell of Leeds in the County of York
"
Mechanical Engineer for an Invention of IMPROVEMENTS IN CENTRIFUGAL
GOVERNORS AND EXPANSION GEAR"
PROVISIONAL SPECIFICATION left by the said Wilson Hartnell at the
Office of the Commissioners of Patents on the 29th December 1883.
WILSON HARTNELL of Leeds in the County of York Mechanical Engineer
"IMPROVEMENTS IN CENTRIFUGAL GOVERNORS AND EXPANSION GEAR
"
This invention has for its object improvements in centrifugal governors and
expansion gear.
The governor levers are bent to a right angle or slightly acute angle. The
centres of the levers are pivotted to a slide on the governor spindle. The weight
is at one end of the lever the other end is furnished with a friction wheel which
rests against a disc or fixed abutment through the action of the spring on the
spindle which presses the slide so as to close the governor weights.
Motion is communicated to the controlling or expansion gear by another slide
beyond the abutment or beyond the weights. This slide coupled to the slide
carrying the levers.
By this construction the governor can be made as nearly isochronous as desired.
Also two three four or more governor weights can be conveniently arranged around
the spindle to obtain increased power in a given space.
The expansion gear which I prefer to attach to this governor consists of a
slide valve on the main valve, both valves having oblique ports oppositely inclined
at each end.
The valve spindle is furnished with a finger or fingers in recesses on the cut off
valve These fingers may be forged on the valve spindle or may be on a loose piece
bolted firmly between the usual adjusting nuts.
The valve rod is loosely screwed into the valve rod cross head.
A lever is fixed to the valve rod and traverses with it but is connected
transversely to the governor.

page_text: On the governor weights moving radially the valve rod is twisted on its axis
and varies the cut off by raising or lowering the cut off valve.
I am aware that it has before been proposed to vary the cut off in this manner.
The improvements here consist in the arrangements whereby (apart from the
governor connection) there are no loose pieces in addition to the ordinary valve
rod and expansion slide. There is thus great simplicity of mechanism and
durability.
The governor may be placed vertically horizontally or inclined and either end
upwards.
It may be used to actuate any form of controlling gear. The expansion also
may be controlled by hand only if desired.
By a further improvement that part of the lever which receives a twisting
movement from the springs has an adjustment for altering its effective length such
as by allowing the friction wheel to be traversed in a slot.
By this means the governor can be adjusted not only to run at any reduced
speed within say about half the maximum speed but it may be made as nearly
isochronous as desired at any of the reduced speeds.
This reduction of the effective leverage of the spring is applicable to both of my
previously patented governors and to spring governors in general which otherwise
require special springs for each special condition of speed and sensitiveness.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Wilson Hartnell in the Patent Office on the 28th June 1884.
WILSON HARTNELL of Leeds in the County of York Mechanical Engineer
* IMPROVEMENTS IN CENTRIFUGAL GOVERNORS AND EXPANSION GEAR”
This Invention has for its object improvements in centrifugal governors and
expansion gear.
The governor levers are bent to a right angle or slightly acute angle. The
centres of the levers are pivotted to a slide on the governor spindle. The weight
is at one end of the lever the other end is furnished with a friction wheel which
rests against a disc or fixed abutment through the action of the spring on the
spindle which presses the slide so as to close the governor weights.
Motion is communicated to the controlling or expansion gear by another slide
beyond the abutment or beyond the weights. This slide is coupled to the slide
carrying the levers.
By this construction the governor can be made as nearly isochronous as desired.
Also two three four or more governor weights can be conveniently arranged around
the spindle to obtain increased power in a given space.
The expansion gear which I prefer to attach to this governor consists of a slide
valve on the main valve, both valves having oblique ports oppositely inclined at
each end.
The valve spindle is furnished with a finger or fingers in recesses on the cut off
valve. These fingers may be forged on the valve spindle, or may be on a loose
piece bolted firmly between the usual adjusting nuts.
The valve rod is loosely screwed into the valve rod cross head.
こ
A lever is fixed to the valve rod and traverses with it but is connected
transversely to the governor.
On the governor weights moving radially the valve rod is twisted on its axis
and varies the cut off by raising or lowering the cut off valve.
I am aware that it has before been proposed to vary the cut off in this manner.
The improvements here consist in the arrangements whereby, (apart from the
governor connection), there are no loose pieces in addition to the ordinary valve
rod and expansion slide. There is thus great simplicity of mechanism and
durability.
The governor may be placed vertically horizontally or inclined and either end
upwards.
It may be used to actuate any form of controlling gear. The expansion also
may be controlled by hand only if desired.
By a further improvement that part of the lever which receives a twisting
moment from the spring has an adjustment for altering its effective length such as
by allowing the friction wheel to be traversed in a slot.
any
By this means the governor can be adjusted not only to run at reduced
speed within say about half the maximum speed but it may be made as nearly
isochronous as desired at any of the reduced speeds.
This reduction of the effective leverage of the spring is applicable to both of
my previously patented govenors and to spring govenors in general which otherwise
require special springs for each special condition of speed and sensitiveness.
To illustrate more clearly the particulars of my invention I have herewith
appended Drawings showing the governor and expansion gear applied to a
compound engine since filing my Provisional Specification.
Figures 1 to 8 show the governor and its details. The governor levers A are
formed so that the centres B. C. D form rather less than a right angle. The
7

page_text: weight B is at one end of the lever, the pin C connects it to the slide E. The
end at D is furnished with a friction wheel which rests against the disc F owing
to the pressure of the spring G. The sliding collar beyond the abutment is in this
case coupled to the slide carrying the levers by being cast in one piece with it. In
this case also there are four governor balls.
Figure 2 shows an end view of the governor lever.
Figure 3 shows another view of the disc F.
Figures 4 and 5 are two more views of the split conical bush showing how the
connecting strips of the two ends of the slide E pass through G.
Figures 6. 7 and 8 are details of the slide E.
Figures 9 to 12 refer to the slide valve and spindle.
Figure 9 is a cross section through the valve chest, through the main valve H
and the cut off valve I. This view shews the projecting finger J on the valve
rod K which raises or lowers the cut off valve when the governor twists the
valve rod.
Figure 10 shows the oblique ports in the back of the slide valve H.
Figure 11 shows the side view of the cut off valve I and the recesses L.
Figure 12 is a longitudinal section of the valve chest, of the valves H, I, and of
the tubular pieces of which the fingers J. J. form a part and shews how this piece
may be secured between the double nuts M and the washers N. N. but prevented
from twisting independently of the valve spindle K by the transverse key O in a
long slot. The finger piece is of such a length that when it is nipped tightly the
cut off valve I is free to move vertically but has no end play.
Figures 13 and 14 show the governor as attached to the engine.
The action will be obvious. As the balls B open or close the slide E is traversed
on the spindle and by means of the lever Q the connecting rod R and the lever S
the valve rod is twisted.
The twisting of the valve rod causes the finger J to raise or lower the cut off
valve. Since the port edges are oblique the position of the cut off valve rod when
the port closes will vary and so therefore will the position of all other moving parts
including the piston. The expansion of steam in the cylinder is therefore varied
according to the position of the governor.
The lever S is rigidly fixed to the valve rod K and traverses with it as the valve
rod is moved by the cut off eccentric. The valve spindle is screwed into the cross
head T the slight end motion due to its twisting being arranged to assist in
making the cut off at opposite ends of the cylinder nearly equal for all parts of the
stroke.
I do not confine myself to the precise details here illustrated. The governor
spring for example may be either side of the abutment disc so also may the sliding
collar for acting on the lever Q. Any convenient number of governor balls may
be used from two upwards.
Also the number of oblique ports may be more or less, they may be inclined
either upwards or downwards from the valve centre.
The cut off valve here shown closes the oblique ports of the main valve on their
edge nearest the main valve centre, but their outer edge might be closed by a
rearrangement of the position of ports on the cut off valve, in which case the cut
off eccentric would be in advance of the main eccentric instead of behind it.
Figure 15 illustrates the further improvements by which C. D which receives a
twisting moment of the spring has an adjustment for altering its effective length
by allowing the friction wheel to be traversed in a slot, bringing D nearer to C or
vice versa in a straight line joining their centres.
What I claim is :-
First. The construction of a centrifugal governor with an abutment disc or
surface against which the levers carrying the governor balls thrust whilst in
diverging they compress the controlling spring.
Second. In such governors the construction of the part of the lever which

page_text: receives a twisting moment from the spring in such manner that its effective length
may be varied and adjusted.
Third. The means for imparting motion to a cut off valve, where the valve rod
by an endwise movement carries the valve with it to and fro and by a rotary
motion imparts a transverse motion to the valve through fingers upon the rod
engaging in recesses in the back of the valve.
Fourth. The combination of governor and cut off gear as herein described.
In Witness whereof I the said Wilson Hartnell have hereunto set my hand
and seal this twentyseventh day of June in the year of our Lord One thousand
eight hundred and eighty four.
WILSON HARTNELL (LS.)