Improvements in Differential Speed Governors for Steam Engines and other Motors.
Year: 1896

page_text: Date of Application, 25th Feb., 1896-Accepted, 13th June, 1896
COMPLETE SPECIFICATION.
Improvements in Differential Speed Governors for Steam Engines
and other Motors.
I, JOSIAH Dow, Mechanical Engineer, of No. 5119 Pulaski Avenue,
Germantown, Philadelphia, Pennsylvania, U.S. America, do hereby declare
the nature of this invention and in what manner the same is to be performed
to be particularly described and ascertained in and by the following statement:-
My invention relates to the construction and arrangement of differential speed
governors for steam engines and other motors, in such a manner as to obtain the
desired differentiation with great steadiness of action and sensitiveness to every
change of speed so that the cut-off is controlled without overrunning, rebounding,
or what is sometimes termed "hunting " and with extreme delicacy or great
rapidity.
I shall describe a governor and its gear according to my invention referring to
the accompanying drawings.
Fig. 1 is a front elevation partly sectional. Fig. 2 is a side elevation and Fig. 3
is a plan.
1 is a frame, and 2 the main rotary-shaft driven by the engine or motor through
any suitable gear. This shaft has two horizontal radial arms 3, fixed to and
revolving with it.
In the frame 1 is supported a horizontal bevil wheel 4, having its boss vertically
extended as a sleeve 5 loosely surrounding the upper portion of the shaft 2; and
outside the sleeve 5 there is another horizontal mitre wheel 6 having a sleeve
hub 7 by which it is supported in the governor frame, as hereinafter described.
The two wheels 4 and 6 though concentrically sleeved upon the shaft 2, are
otherwise independent of each other and of the shaft.
The uppermost wheel 6 has geared with it and revolving around it two vertical
mitre wheels 8 of the same diameter as 6, these wheels being mounted upon the outer
ends of the arms 3. The wheels 8 have fixed to them so as to revolve with them,
subsidiary bevil pinions 9 which gear with the wheel 4 of larger diameter. For
convenience of illustration the wheel 4 is shown as having double the diameter of
the pinions 9, but any other suitable proportion may be used.
The vertical sleeve 5 is extended upward beyond the upper end of the shaft 2,
and there has fixed to it in the same axial line a vertical shaft 10 carrying the
balls 11 and their arms 12 and 13 and sliding collar 14.
In the sleeve 5 are steadying bushings 15 surrounding the main
shaft 2 being free to turn within the sleeve 5 does not control the
wheel 4 or shaft 10 except through the wheels 8 and pinions 9.
the wheel 6 is also perfectly free to turn outside of the sleeve 5.
holds the sleeve 5 and the bearing 17 holds the sleeve 7.
shaft 2, but the
movement of the
The sleeve 7 of
The bearing 16
In order to facilitate easy motion of the parts the bearings and the collars 18
and 19 which are fixed on the sleeves have annular grooves holding antifriction
balls 20,
When motion is communicated to the main shaft 2, the wheels 8 revolve around
the wheel 6 with which they gear. If 6 were held at rest the wheels 8 being
subjected to no resistance, through the pinions 9 and wheel 4, the wheels 8 would
revolve once round their own axes while passing once around the wheel 6 of equal
diameter, and the pinions 9 would also, necessarily, turn once upon their own axes
along with the wheels 8. The pinions 9, however, always moving with the gears 8,

page_text: meet with resistance having to cause revolution of the balls 11 through the
wheel 4, and as the piuious 9 have a diameter half that of the wheel 4, in turning
once round their own axes they carry the wheel 4, and with it the balls, through
half a revolution, they themselves making one revolution around the main shaft 2.
But the turning of the pinions 9 once round their own axes causes their com-
panion wheels 8. to also turn once upon their own axes while turning once round the
wheel 6, and this would leave the wheel 6 at rest although geared with the
wheels 8. Thus it will be understood that for the normal rate of revolution of
the engine or other motor, the balls 11 must be of such weight and must revolve
at such radius that the force required to keep them at a certain rate shall be just
sufficient to oblige the pinions 9 to carry with them the wheel 4, and consequently
the halls, through the half of one revolution balanced against the resistance of the
cut-off connections of the engine, while the pinions 9 go through one revolution
around the wheel 4 and the main shaft. With the gearing proportioned as shown,
the balls will make just one half as many revolutions as the wheels 8 and pinions 9
when the wheel 6 is left at rest, because the wheel 4 being twice the diameter of
the pinions 9 they may carry it with them to the extent of half a revolution, and
yet themselves turn a whole revolution around their own axes carrying the wheels 8
round with them.
It is to be noted that in this governor the halls 11 are not employed as in
ordinary centrifugal governors in which the ascent and descent of the hall and
collar effect the required changes in the cut-off. In this governor, on the contrary,
the ascent and descent of the collar 14 has no direct connection whatever with the
cut-off mechanism. But the balls 11, in their resistance to revolution, governed
by the laws well known to control the pendulum and kindred balancing devices,
act in much the same manner on the wheel 4, as does the familiar chronometer
balance. As the resistance to motion of the balls, when revolving in a path of
unvarying diameter, is always exactly the same at the same rate of speed; as this
resistance is made exactly the resistance of the engine cut-off and its connections;
and as the motion of the balls is attained through the resistance between the
wheel 4 and pinions 9, the pinions 9 always moving faster about the main axis or
shaft 2 than the wheel 4 does,, a change in the number of revolutions of the
engine, from the normal, does not affect the normal revolutions of the
balls 11 unless the speed becomes so very much less as not to give the pinions 9
the surplus of movement required to keep the wheel 4 up to the normal number of
revolutions, in which case the action, through the wheel 6 and cut-off connections,
toward the longest cut-off would take place with great rapidity. Should the speed
turn suddenly toward a great excess, as the balls would move no faster, being
driven only by the resistance between the wheel 4 and pinions 9 and not by direct
action of their teeth in revolution, the movement toward the shortest or complete
cut-off would be effected with as great rapidity. That is, with a motion of the
shaft 2 slower than the normal speed the pinions 9 will receive less movement upon
their own axes, after yielding the necessary force to maintain the balls at their
normal speed; and consequently the wheels 8 will not make a complete revolution
upon their own axes while passing once around the wheel 6 and they will con-
sequently carry the wheel 6 with them through a greater or less arc of movement.
But should the speed of the main shaft 2.become greater than the normal, then the
pinions 9 will receive more than one revolution upon their own axes while revolving
once about the main axis, carrying with them the wheels 8 which will transmit the
excess of movement to the wheel 6 causing it to revolve backwards, or in the
opposite direction to the revolution of the wheels 8, to the extent of the excess
over what is necessary to the turning of the wheels 8 once upon their own axes
while revolving once around the wheel 6. It will thus be seen that the wheel 6 is
forced to turn backwards from the direction of revolution of the wheels 8 and
pinions 9 when the speed of the engine or other motor becomes greater than the
normal and that it turns in the same direction with that revolution when the speed
of the engine falls below the normal. Also that, regardless of the duration of this

page_text: turning backward or forward of the wheel 6, the new point of cut-off will be
steadily maintained on the uormal rate of speed being restored; because the
wheel 6, at the normal speed, remains without any movement; the balance with
the balls 11 being such that the wheels 8 turn exactly once on their own axes while
revolving once about the wheel 6 through which the cut-off is controlled.
The movements of the wheels 6 in one direction or the other, and its balanced
rest at the normal speed, are transmitted through a spur wheel 21 on the sleeve 7"
or its collar 19 to a spur wheel 22 and a pinion 23 fixed to 22 on an axis mounted in
the governor frame. The pinion 23 engages a toothed segment 24 on a rock
shaft 25 having an arm 26 or other suitable device for connecting with a cut-off or
valve gear. Instead of a segment 24, a straight rack may be used connected
directly with the cut-off or valve gear. Or the wheel 6 may gear directly with a
segment or rack, the wheel 21 and pinion 22 being then dispensed with.
As the regulating effect of the balls 11 depends directly upon their weight with
relation to the diameter of their circle of revolution and the square of the linear
velocity of motion, it is evident that the normal rate of speed which is determined
by them will be greatly affected by the radial positions of the balls and that the
raising or lowering of the collar 14 will afford means of holding them in such.
radial position as may be desired to regulate the normal speed, an outward
movement of the balls will increase their resistance to revolution and, consequently,
permit fewer revolutions through the resistance of the pinions 9, which is a fixed
amount derived from the resistance of the cut-off gearing and connections; and
conversely, an inward movement of the balls to a less radial distance will decrease
their resistance to revolution and permit a greater number of revolutions. To-
secure this regulation and permit it to be effected while the governor is in motion,
a weighted lever arm 27 is pivotted at 28 on the governor frame 1 has at one end
forks 29 to engage lugs on the collar 14, and on the lever 27 there is a movable.
weight 30, which can be adjusted so as to determine any desired radial position of
the balls,
It may be noted that the action of the wheels 8 when turning the wheel 6 to
effect a longer or a shorter cut-off continues in one direction until the normal speed
is restored, the movement being very slight and slow while the variation from the:
normal is slight; greater and more rapid when the variation is greater; and that
the movement of the wheel 6, still in the same direction, decreases as the speed
approaches the normal, until it comes to rest when the normal speed is reached,
leaving the wheel 6, and, consequently, the cut-off in the new position without any
opportunity for rebound or "hunting," as is commonly the case with the usual
forms of centrifugal governors which do not set up a new point of cut-off but.
continually attempt to correct the old one.
The balls 11 are held in motion, through the connected train of gearing, by the
resistance of the cut-off or valve-gear connections, but have no actuating connection
with the cut-off or valve-gear; and they act only as a chronometrical balance to
set a fixed number of revolutions.
With every change of speed from the normal for which the engine or motor is
adjusted, the governor mechanism acts promptly, steadily, and with great
sensitiveness to transmit the required changes as sensitively and directly to the
cut-off, either with great delicacy of movement or great rapidity, as the immediate-
needs of the engine may determine.
I have explained at considerable length the indirent action of the governor on
the cut-off, in which respect it differs essentially from ordinary centrifugal governors,
but, as this is an important feature of my invention,. I may more briefly explain the
action as follows:
The weight 30 being adjusted so as to hold the balls 11 in the position radially which
they would assume when revolving at a certain speed the wheel 4 revolving with them
and consequently the pinions 9 and wheels 8 revolving on their own axis at such a rate
that the wheels 8 in revolving round the wheel 6 do not cause it to revolve, then the cut
off or valve which is mechanically connected to the wheel 6 remains at rest. But if the

page_text: shaft 2 began to revolve at a greater or less speed, then the inertia of the balls 11 by
resisting the change of velocity would throw a strain the one way or the other on
the wheel 4 from which they are driven, urging it backwards or forwards as the
case might be, and thereupon the wheels 8 and with them the pinions 9 would be
caused to revolve at a different rate around their axes and consequently motion
would be imparted to the wheel 6 and by it to the cut-off or valve, so varying the
cut off until the speed of the shaft 2 should return to the normal.
Having now particularly described and ascertained the nature of this inven-
tion and in what mauner the same is to be performed, I declare that what I
claim is :-
1. In a governor for motors, the combination of a rotary shaft having opposite
radial arms, a bevil and a mitre wheel sleeved concentrically but freely upon the,
shaft, mitre wheels mounted on the arms of the shaft in gear with the mitre wheel
on the shaft bevil pinions, fixed to the mitre wheels on the arms and gearing with
the bevil wheel which is of larger diameter than the pinions, governor balls
connected to an adjustable collar on a shaft fixed to the sleeve of the bevil wheel
and means for connecting the mitre wheel with cut-off devices substantially as
described.
2. In a governor for motors, the combination of the frame 1, the rotary shaft 2
provided with radial arms 3, the mitre wheels 8 mounted on these arms and having.
pinions 9 fixed to them, the mitre wheel 4 loosely sleeved on the shaft 2 and
gearing with the pinions 9 of smaller diameter the mitre wheel 6 loosely sleeved on
the sleeve of the wheel 4 and gearing with the mitre wheels 8 the segment or
rack 24 connected to a cut-off and geared to the sleeve of the wheel 6, the shaft 10
fixed to the sleeve of the wheel 4, the collar 14 sliding on the shaft 10, balls 11
connected with the collar and carried by the shaft 10, the lever 27 connected with
the collar and carrying the adjustable weight 30 substantially as described.
3. A governor for motors having balls radially adjusted to determine a certain
number of revolutions, and kept in motion by differentially controlled mechanism
between the balls and the cut-off or valve gear connections with which the balls
have no connection substantially as described.
Dated this 25th day of February 1896.
ABEL & IMRAY,
Agents for the Applicant.