Improvements in Drum Governors for Regulating the Speed of Motors.
Year: 1892

page_text: Date of Application, 27th Oct., 1892
Complete Specification Left. 27th July, 1893-Accepted, 2nd Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in Drum Governors for Regulating the Speed of
Motors.
DAVID JAMES MURRAY Engineer 54 Warwick Road Ipswich. I do hereby
declare the nature of this invention to be as follows:-
This crankshaft governor commonly called a drum governor is to secure
regularity of speed under varying loads by automatically changing the steam cut
off, at the same time keeping a suitable lead at every grade of expansion.
In the drawing there are three views with reference letters, a particular letter
is used in all views for the same part.
As arranged in the drawing the governor is suitable for an automatic motor with
single slide valve, the centre S of the eccentric sheave A being made to follow a
curve R for motor running in one direction and a curve Q for opposite direction.
The above curve is described from the centre T of disc B.
By changing the relative position of the centres of eccentric sheave A, eccentric
sheave driving disc B, and the crankshaft L, various paths may be obtained by the
motion of the governor, for the eccentric sheave centre, suitable for varying the
rate of expansion of steam either in the case of a single slide valve, or in the case
of an expansion valve working on the back of a main slide valve.
The chief feature of the invention is the attachment of the eccentric sheare A
to a disc B guided at its circumference by the main casting M of the governor, and
The frictional
held in position by the cover plate C which is fixed by screws.
resistance at circumference of disc B, due to load on slide valve spindle, acts at a
comparatively large radius, and will be of service in keeping the governor from
"jumping" and "hunting."
At the same time the governor weights have control over the angular position of
the disc B by means of the connecting links D & E.
The circumference of disc B is shown cylindrical, but it may be conical, and the
inside edge of plate C coned to suit, so that cover plate C and thickness of rim of B
are in one plane.
The weights rotating with the shaft act under the influence of the changes of
centrifugal force due to increase & decrease of speed of shaft. Both governor
weights are shown in two extreme positions. One governor weight W is shown
full out with hatched edge and the other weight W₁ full in with hatched edge.
The weights in moving from full out to full in, change the position of the links
from D to D¹ and from E to E'.
To reverse the engine the links are coupled to the disc B in a different manner.
Links D & E are put in positions F & G. In this case when the governor weights
move from full out to full in the links change in position from F to F' and
from G to G¹.
The centrifugal force acting on the weights is resisted by the spiral springs H
& H. The stops J J' also K K' limit the travel of the weights.
Weights W&W' are connected to links D & E by the pins N & N'.
& E are connected to eccentric driving disc B by the pins P & P¹.
Links D
The movement of the weights W & W' gives the disc B an angular movement
and changes the position of the centre S of the eccentric sheave A.
Dated this 26th day of October 1892.

page_text: !!
Improvements in Drum Governors for Regulating the Speed of
Motors."
I, DAVID JAMES MURRAY, of 9 Billiter Square; care of Robinson, Fleming & Co.
in the City of London, Engineer, 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 relates to crankshaft governors commonly called drum governors
and has for object to secure regularity of speed in a fluid pressure motor under
varying loads by automatically changing the cut off of working fluid at the same time
keeping a suitable lead at every grade of expansion. It can be applied to drive
and control any form of valve capable of being worked by an eccentric, such as a
slide valve, a cut off valve, a Cornish or lift valve, or a Corliss valve without trip
gear:
In the drawing filed with my Provisional Specification there are three views of
an arrangement of governor according to this invention with reference letters, the
same letter being used in all views to denote the same part... Sheet II filed with
and forming part of this Complete Specification contains diagrams illustrating more
clearly the position of some parts of the mechanism of drum governors according to
this invention.
As arranged in Sheet I of the drawings the governor is suitable for a motor with
single slide valve the centre S of the eccentric sheave A being made to follow a
curve R when the motor is running in one direction and a curve Q for the opposite
direction. The said curves are described from the centre T of the disc. B.
By changing the relative positions of the centres of the eccentric sheave A,
eccentric sheave driving disc B, and the crank shaft L, the eccentric sheave centre
may be made to follow various paths suitable for varying the rate of expansion of
working fluid either in the case of a single slide valve or in the case of an expansion
valve working on the back of a main slide valve.
Figs. 1 and 2 Sheet II show diagrammatically the path of the eccentric sheave
centre relatively to the crank of an engine having a single slide valve, the path
represented in Fig. 1 being that followed. when the engine is running in one
direction and that in Fig. 2 being that followed when it is running in the opposite
direction.
Figs. 3 and 4 are similar views to Figs. 1 and 2 of the paths of the eccentric
sheave centre of an engine having an expansion..valve.
With the governor weights full out at. maximum radius the centre of the
eccentric lies on the line joining the centre of the crank shaft and the centre of
eccentric sheave driving disc. This position is not essential, and the centre of
the eccentric may lie to one side of this line..
The eccentric sheave A is attached to a disc B guided at its circumference by.
the main casting M of the governor, and held in position by the cover plate C.
The frictional resistance at the circumference of the disc B, due to the load on the
slide valve spindle, acts at a comparatively large radius, and is of service in keeping
the governor from "jumping" and "hunting."
At the same time the governor weights have control over the angular position of
the disc B by means of the connecting links. D and E. The circumference of the
disc-B is shown cylindrical but it may be conical and the inside edge of the plate C
coned to suit, so that the. cover plate C does not project, above the rim of the
disc B.
The weights rotating with the shaft act under the
centrifugal force due to increase and decrease in the
governor weights are shewn in two extreme positions.
shown full out with hatched edge and the other weight
influence of the change of
speed of the shaft. Both
One governor weight W is
W₁ full in with hatched

page_text: edge. The weights in moving from the position of full out to full in change the
position of the links from D to D' and from E to E'.
To reverse the engine the links are coupled to the disc B in a different manner.
The links D and E are put in positions F and G. In this case when the governor
weights move from full out to full in the links change in position from F to F¹ and
from G to G¹.
To reverse the engine when governor works an expansion valve the position of
the centre T is changed so that it may bear the same relative position to the crank
when running in the new direction as it did when running in the old direction. This
is done by having two keyways in the governor main casting and one key bed in
the shaft opposite the crank. The links are changed as for single slide valve. The
main eccentric is changed as in any expansion valve arrangement, to reverse the
action of main slide valve. The toggle joint action of the links E E' and G G¹
assists in keeping the governor steady.
The centrifugal force acting on the weights is resisted by the spiral springs H
and H. The stops J, J'also K K' limit the travel of the weights.
The weights W and W₁ are connected to links D and E by the pins N and N'.
The links D and E are connected to eccentric driving disc B by the pins P
and P¹.
The movement of the weights W and W₁ gives the disc B an angular movement
and changes the position of the centre S of the eccentric sheave A with relation to
the centre of the crank shaft.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. A drum governor having an eccentric sheave fixed on an eccentric sheave
driving disc whose centre is so placed; relatively to the centre of the sheave and
the centre of the crank shaft, that motion of the said disc around its centre
increases the angle of advance and diminishes the throw of the eccentric sheave,
and vice versa substantially as described.
2. The improved drum governor constructed arranged and operating substantially
as described and shewn,
Dated this 25th day of July 1893.
DAVID JAMES MURRAY.