Improvements in Steam Engine Governors.
Year: 1894

page_text: Date of Application, 5th Jan., 1894-Accepted, 10th Feb., 1894
COMPLETE SPECIFICATION.
Improvements in Steam Engine Governors.
We, JULIUS BEGTRUP, and JAMES HENRY MCEWEN, both of Ridgeway,
Elk County, Pennsylvania, U.S.A., Engineers, 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 :-
This invention pertains to improvements in governors designed for regulating the
speed of steam engines etc., and relates particularly to that class of governors in
which the governor is carried directly by the shaft of the engine and operating
to modify the position of the eccentric, this type of governors being known as
"shaft governors."
The present improvements will be readily understood from the following
description taken in connection with the accompanying drawing in which :-
-
Fig. 1, is a face view or elevation of a governor exemplifying the present
invention:
Fig. 2, a horizontal section of the same:
Fig. 3, a vertical section through the cylinder of the dash-pot: and
Fig. 4, a side elevation, part vertical section, at intermediate portions of the
governor arm, illustrating the construction as modified by so enlarging the eccentric
that the engine shaft may pass through it.
In the drawing :-
A, indicates the engine shaft:
B, a wheel fast thereon, which wheel, so far as the governor is concerned, is a
mere carrier for the governor :
C, a pivot carried by the wheel eccentric to and parallel with the axis of the
shaft:
D, an arm having an intermediate point journalled at the pivot C, this arm
extending across the wheel in a substantially diametrical line, so far as mere form
of arm is concerned :
E, a weight at one end of this arm:
F, a weight at the other end of the arm:
G, the eccentric mounted upon the arm, in proper relation to the axis of shaft A,
this eccentric being of any size found expedient, Figs. 1 and 2 showing it as small
and forming a mere eccentric pin, while Fig. 4 shows it so much enlarged that it
may have an open centre sufficiently large to permit of the extension of shaft A
axially through the plane of the arm and eccentric
H, a spring acting between an attaching point on the wheel and the arm and
tending to resist the rocking of the arm in one direction of motion upon its pivot C:
J, a dash-pot cylinder formed within weight F, and provided with a piston whose
rod projects tangential to the axis of shaft A:
K, a pivot carried by the wheel in the line of the piston-rod:
L, a bell-crank pivoted to this pivot, one arm of this bell-crank forming, in
effect, the piston-rod of the dash-pot to which it is rigidly attached, the other arın
being formed with a weight:
M, a circle of anti-friction rolls at the bearing of arm D upon pivot C, forming at
that point an anti-friction roller bearing:
N, a pair of limiting stops carried by the wheel and
O, a strike carried by the arm D and adapted to be arrested by stops N at limits

page_text: of desired rocking motion of arm D upon its pivot, this strike being preferably
provided with buffers to ease the jar at times of engagement.
Disregard for the present, weight E. As the governor revolves in the direction
of the arrow of Fig. 1, centrifugal force tends to move weight F, and the mass of
the arm D, further from the axis of shaft A, and the tension of spring H resists
this motion. The centre of gravity of the arm and weight are outwardly beyond
a line cutting the centres of shaft A and pivot C. Consequently, centrifugal force,
due to increase in speed, will rock the arm and strain the spring and move the
eccentric in an arc across the shaft, thus shifting the eccentric to a position suited
to effect a reduction of speed. The arm can rock no further than permitted by the
appropriate one of stops N. The piston of the dash-pot is to be loose enough to
permit of leakage of air past it. Consequently the dash-pot will resist extremely
sudden or jerky movements of the arm upon its pivot, but will permit more
deliberately applied forces to move the arm. As the governor revolves, centrifugal
force acts on the piston of the dash-pot and seeks to press it forcibly against the
outer portion of its cylinder thus tending to produce undesired friction and wear of
the cylinder and piston. But, in the present construction, the piston is counter-
balanced by means of the weight upon the bell-crank L. The same centrifugal
force that tends to move the piston outwardly tends also to move its rigidly attached
counter weight outwardly, and, the parts being designed in proper balance, the
centrifugal effect is nil.
Weight E upon arm F tends to balance the arm upon its pivot C and it also gives
to the arm structure a virtual balancing upon the centre of rotation of the governor,
upon the axis of shaft A.
Assume, now, that this combined structure is in rotation at certain speed, and
assume that the speed of the wheel is suddenly increased. The other member of
the pair, the arm, by its inertia, would seek to maintain the former speed and lag
behind the wheel. And in the present case it does so, the lagging motion not how-
ever taking place upon the axis of shaft A but upon the pivot C. The effect of
this lagging motion is to move the eccentric in the same direction as it would be
moved under the action of centrifugal force due to increased speed. Therefore,
assuming that there is no motion of the governor arm due to centrifugal force it
will be seen that governing action takes place by reason of the inertia of the arm
structure, that arm structure seeking to lag if the wheel takes on accelerated
velocity, and seeking to maintain its former speed if the wheel takes on retarded
velocity, the arm structure therefore forming an inertia weight, with its mass
distributed at each side of its pivot, which lags behind the quickening wheel and
stands ahead of the lagging wheel, its change of position with reference to the
wheel producing appropriate action upon the eccentric. And it will furthermore
become apparent that the inertia weight, having thus shifted with reference to the
wheel by reason of its inertia, may assume an infinite variety of positions with
reference to the wheel, not tending by its inertia to return to any particular position
by reason of the wheel having returned to normal speed. The arm structure need
not necessarily have the arm and weight form indicated. It may be given any desired
form, it only being necessary that it shall be pivoted eccentric to the axis of rotation
of the governor and that its centre of gravity shall at all times lie to one side of a
a line cutting its pivot and the axis of rotation of the governor.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that we
claim is :-
1. In a steam engine governor, the combination, substantially as set forth, of a
rotary carrier, and a combined inertia weight and centrifugal weight carried thereby
and connected to a valve-moving part, as an eccentric.
2. In a steam engine governor, the combination, substantially as set forth, of
a rotary carrier, a combined inertia weight and centrifugal weight carried

page_text: thereby and connected to a valve-moving part, as an eccentric, and a dash-pot
carried by the carrier and arranged to check sudden movements of the combined
weight.
ALLISON BROS.,
Agents for the Applicants.