Improvements in Governing and Valve Operating Gear for Steam Engines.
Year: 1895

page_text: Date of Application, 18th Jan., 1895
Complete Specification Laft 19th Oct 1505 10cented
22nd Nove
400L
PROVISIONAL SPECIFICATION.
Improvements in Governing and Valve Operating Gear for Steam
Engines.
I, HERMANN KÜHNE, of 25-35, New Broad Street, London E.C., Engineer,
(communicated from abroad by Alexander Paul Clemens, of Schumanstrasse 42,
Dresden in the German Empire, Engineer), do hereby declare the nature of this
invention to be as follows:-
My invention relates to governing and valve operating gear for steam engines
and consists; in a new method of and arrangement for opening the steam admission
valves at a fixed point in such manner as to prevent the work of opening the
valve from re-acting on the governor; and in a method of and arrangement for
varying the speed of the engine by a spring capable of being operated while the
engine is in motion.
It has been found in variable cut off gear for steam engines that the work of
opening the steam valve especially the work of opening a balanced lift valve is
considerably greater than the work involved in increasing the opening of the valve
after it has been lifted off its seat. That is, the pressure required to lift the
valve off its seat is greater than the subsequent pressure necessary to hold it open
or to increase its opening.
In variable cut off gears of the ordinary types the valve opening part is
usually held to its work of opening the valve by the governor and consequently
the governor has to be made powerful enough to resist the tendency to displace-
ment caused by the strain of opening. All governors so connected are liable to
periodic displacement corresponding to the opening period and so are liable to
hunt.
Part of my invention consists in so arranging the valve operating parts that
the opening of the valve is accomplished by a fixed can or other contrivance
firmly connected to the engine or the valve shaft in such manner as to open the
valve positively at a predetermined point without connection with the governor,
while the governor determines the point of cut off within the required limits.
In one method of carrying this part of my invention into effect I arrange a valve
shaft at right angles to the crank shaft and driven froin it by gearing at the same
speed as the engine; on the valve shaft I fix a cam which rotates with the shaft
and is not influenced by the governor. This cam I arrange to open the lift valve,
preferably of the double beat type, and I cut away the cam so that it allows the
valve to close very early in the engine stroke, at the point in fact which is fixed
for the minimum of steam admission. This cam tbus opens the valve positively at
the point desired. On the valve shaft close to the fixed cam I place a second cam.
This cam however is loose on the shaft so as to be capable of partial rotation
round the shaft or round an eccentric on the shaft and it is controlled as to its
position round the shaft by any known type of governor.
I prefer however a governor of the type in which hinging or pivoting weights
re pivoted to a drum or cylinder or disc or other connection keyed to the shaft
and rotating with it. And I prefer the centrifugal force to be resisted by a central
pring or springs bearing upon the inner ends of short levers projecting from the
ivoting weights.

page_text: I also prefer to connect the governor weights to the second cam by links and
pins in such manner that the expansion of the governor weights pulls the cam or
eccentric disc round the shaft or round an eccentric on the shaft in one direction
while their contraction moves the said cam or disc in the other direction.
A roller is provided running on the first cam to open the steam valve by means
of suitable levers and this roller is made wide enough to roll on both the first and
second cams which are placed, as I have described close together. When the
governor weights are in their innermost position the second cain is fully extended
with reference to the fixed cam and so the roller which is raised by the fixed cam
is held up by the second or governor cam for the maximum period of steam
admission; as the speed increases and the weights expand the second or governor
cam is drawn back round the shaft to bring its cut off edge nearer to the cut off
edge of the fixed cam and so the point of cut off becomes earlier and earlier. To
prevent the portion of the second or governor cam which is pulled round past the
opening edge of the fixed cam from interfering with the opening edge the curved
face of the said governor cam is struck from a point out of the centre of the
valve shaft and so the governor cam surface passes under the line of the fixed
cam surface at the point of opening.
The fixed cam surface is struck from the same point so that at the position
where the two cams adjoin each other the two surfaces follow one curve on which
the roller runs.
By this device the valve is always lifted from its seat by the fixed cam and
the cut off determined by the governor until the governor has moved through its
full range when the fixed cam only, both admits and cuts off the steam.
Suitable links and levers are adopted to connect the valve spindle to the roller
which is actuated by the cams, and springs are used if necessary to return the
valves.
Part of my invention consists in an arrangement for varying the speed of the
engine while running by acting on the central springs by means of an external
adjustable spring preferably adjusted by screw action.
In one method of carrying this part of my invention into effect the central
springs of the governor one on each side of the central shaft, are arranged radially,
pressing out the lever ends of the governer weights and so closing in the said
weight ends, which are constructed in bell crank fashion. The springs are held
in position at the shaft ends by suitable guides, and covers are provided upon
which the short ends of the bell cranks press. A rod passes through the axis of
each spring through suitable guiding apertures and the outer ends of the two
rods are attached in a convenient manner to the spring covers; the inner en ls
are pressed upon by two expanding bell crank levers pivoted within the drum or
cylinder carrying the governor. The governor or valve shaft up to the inner ends
of these levers is made hollow and a rod or spindle is passed within the hollow
resting only at one or more points within, by means of spherical or ball. This
spindle or rod is arranged to slide within the shaft and rotate with it carried
round by a key or feather. The inner end of this spindle or rod is pressed against
right angle projections from the expanding bell crank levers and the outer end is
connected by a suitable joint such as a ball and socket joint or a fork and sleeve
to a double armed lever connected by stud and eye to a part of the engine frame
or a bearing bracket. The lower end of the lever carries a sliding nut capable
of being moved up and down in an inclined direction by a screw operated by han ile
or hand wheel. This nut pivots to a plunger carrying one or more springs and
the spring and plunger pivot from a fixed point in the engine frame or bearing
bracket; the spring is arranged to press the lever end on the internal spindle and
rod and so cause the inner levers to act on the governor weight levers and so
increase the spring load on the governor.
When the adjusting screw is screwed to bring the nut nearer to the fulcrum of
the lever the pressure on the internal spindle is reduced because of the diminished
leverage and the less compression given to the outside spring.

page_text: By this device I increase or diminish the spring load on the governor weights
t will and so vary the speed of the engine while running.
Dated this 18th day of January 1895.
Improvements in Governing and Valve Operating Gear for Steam
Engines.
1, HERMANN KÜHNE, of 25-35, New Broad Street London, E.C., Engineer,
(communicated from abroad by Alexander Paul Clemens, of Schumanstrasse 42,
Dresden in the German Empire), 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 governing and valve operating gear for steam engines
and consists; in a new method of and arrangement for opening the steam admission
valves at a fixed point in such manner as to prevent the work of opening the
valve from re-acting on the governor; and in a method of and arrangement for
varying the speed of the engine by a spring capable of being operated while the
engine is in motion.
It has been found in variable cut off gear for steam engines that the work of
opening the steam valve especially the work of opening a balanced lift valve after
it has been lifted off its seat, that is, the pressure required to lift the valve off its
seat is greater than the subsequent pressure necessary to hold it open or to increase
its opening.
In variable cut off gears of the ordinary types the valve opening part is usually
held to its work of opening the valve by the governor and consequently the
governor has to be made powerful enough to resist the tendency to displacement
caused by the strain of opening. All governors so connected are liable to periodic
displacement corresponding to the opening and so are liable to hunt.
Part of my invention consists in so arranging the valve operating parts that the
opening of the valve is accomplished by a fixed cam or other contrivance firmly
connected to the engine or the valve shaft in such manner as to open the valve
positively at a predetermined point without connection with the governor, while
the governor determines the point of cut off within the required limits.
Referring to the accompanying sheet of drawings.
Figure 1 is a diagrammatic end elevation showing the parts of a steam engine to
which my invention has been applied.
Figure 2 is an end elevation and
Figure 3 is a sectional plan shewing the cams on a larger scale.
Figure 4 is a longitudinal section illustrating a governor operating my improved
cam and also illustrating a second part of my invention and
Figure 5 is a section on the line y Figure 4.
In one method of carrying this part of my invention into effect I arrange a valve
shaft A at right angles to the crank shaft and driven from it by gearing at the
same speed as the engine; on the valve shaft A. I fix a cam B which rotates with
the shaft and is not influenced by the governer. This cam arrange to open the
lift valve, preferably of the double beat type, and I cut away the cam B so that it
allows the valve to close very early in the engine stroke, at the point in fact which
is fixed for the minimum of steam admission. This cam B thus opens the valve
positively at the point desired.
In Figure 1 the cam B is shown as operating the valve spindle G by means of

page_text: the roller D carried in the end of the rod I the said rod being supported on the
levers K and H.
On the valve shaft A close to the fixed cam B I place a second cam C. This
cam however is loose on the shaft so as to be capable of partial rotation round the
shaft or round an eccentric on the shaft and it is controlled as to its position round
the shaft by any known type of governor.
Figures 2 and 3 show an arrangement of the fixed and moving cams in which the
moving cam C rotates round an eccentric having the centre a The main part of the
cam B is struck from the centre of the shaft A but the operating or cam part B is
struck from the centre a of the eccentric. The operating part of the cam C is
also struck from the centre a; the lines Z Z show the radii of both curves.
I prefer a governor the type in which hinging or pivoting weights are pivoted
to a drum or cylinder or disc or other connection keyed to the shaft and rotating
with it. And I prefer the centrifugal force to be resisted by a central spring or
springs bearing upon the inner ends of short levers projecting from the pivoting
weights.
I also prefer to connect the governor weights to the second cam by links and
pins in such manner that the expansion of the governor weights pulls the cam or
eccentric disc round in one direction while their contraction moves the said cam or
disc in the other direction.
Such a governor is shown at Figures 4 and 5 and it will be described herein-
after.
A roller D Figures 1, 2, 3, is provided, running on the first cam B, to open the
steam valve by means of suitable levers and this roller is made wide enough to roll
on both the first cam B and the second cam C, which are placed as I have described
close together. When the governor weights are in their innermost position the
second cam C is fully extended with reference to the fixed cam B and so the
roller D which is raised by the fixed cam B is held up by the second or governor
cam C for the maximum period of steam admission; as the speed increases and the
weights expand, the second or governor cam C is drawn forward round the shaft
moving the direction of the arrow Figure 2, to bring its cut off edge c nearer to
the cut off edge of the fixed cam B and so the point of cut off becomes earlier
and earlier. To prevent the portion of the second or governor cam C which is
pulled round past the opening edge of the fixed cam B from interfering with the
opening edge, the curved face of the said governor cam C is struck from a point a
out of the centre of the valve shaft A as hereinbefore described, and so the
governor cam surface passes under the liue of the fixed cam surface at the point of
opening. This is clearly shown in Figure 2 when the three sets of dotted lines
numbered 1, 2 and 3 indicate different positions of the governor cam. From these
dotted lines it will be seen that the movement of the governing cam does not affect
the point of opening the steam valve, and that this opening is at all times effected
by the fixed cam.
The fixed cam surface is struck from the same point a so that at the position
where the two cams adjoin each other the two surfaces follow one curve on which
the roller runs.
By this device the valve is always lifted from its seat by the fixed cam and the
cut off determined by the governor until the governor has moved through its full
range when the fixed cam alone both admits and cuts off the steam.
Suitable links and levers are adopted to connect the valve spindle to the roller
which is actuated by the cams, and springs are used if necessary to return the
valves. The arrangement of links and levers indicated at Figure 1 is only one of
many such arrangements which may be adopted.
Part of my invention consists in an arrangement for varying the speed of the
engine while running, by acting on the central springs by means of an external
adjustable spring preferably adjusted by screw action.
In one method of carrying this part of my invention into effect shown at

page_text: Figures 4 and 5, the central springs L L of the governor, one on each side of the
central shaft A, are arranged radially, pressing out the lever ends N' N₁ of the
governer weights N N and so closing in said weight ends. The springs L L are
held in position at the shaft ends by suitable guides, and covers are provided upon
which the short ends N' N' of the bell crank press. A rod e passes through the
axis of each spring through suitable guiding apertures and the outer ends of the
two rods are attached in a convenient manner to the spring covers; the inner ends
are pressed upon by two expanding bell crank levers QQ pivoted within the
drum or cylinder M carrying the governor. The governor or valve shaft. A, up to
the inner ends of these levers QQ, is made hollow as at O and a rod or spindle P
is passed within the hollow resting only at one or more points within, by means of
spherical or ball surfaces. This spindle or rod P is arranged to slide within th
shaft and rotate with it carried round by a key or feather. The inner end of this
spindle or rod is pressed against right angle projections from the expanding bell
crank levers Q Q and the outer end is connected by a suitable joint P' such as a
ball and socket joint or a fork and sleeve, to a double armed lever R connected by
stud and eye to a part of the engine frame or a bearing bracket R. The lower
end of the lever R carries a sliding nut S capable of being moved up and down in
an inclined direction by a screw operated by handle S' or hand wheel. This nut S
pivots to a plunger T carrying one or more springs U, and the spring and plunger
pivot from a fixed point T¹ on the engine frame or bearing bracket; the spring U
is arranged to press the lever end on the internal spring or rod so cause the inner
levers QQ to act on the governor weight levers N N and so increase the spring
load on the governor.
When the adjusting screw is screwed to bring the nut S nearer to the fulcrum
of the lever R the pressure on the internal spindle P is reduced because of the
diminished leverage and the less compression given to the outside spring U.
By this device I increase or diminish the spring load on the governor weights at
will, and so vary the speed of the engine while running.
The connection of the governor to the governor cam C is made by levers within
the drum which are not shewn in the drawings, but the effect is to move the cam B
round the eccentric a by the action of the bell crank levers N₁ N¹ operated by the
weights N N and a pin E (Figure 2) operating in the slotted extension C² in a
sleeve carrying the said cam.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is ;-
1. In engine governing gear, the method of opening an admission valve by one
cam or eccentric which is fixed to the engine or valve shaft and continuing the
opening and determining the point of cut off by means of another cam or eccentric
of which the position for cut off is controlled by the governor, for the purpose of
relieving the governor of the strain of opening the valve substantially as herein-
before described.
2. In engine governing gear, a cam as B fixed to the valve or engine shaft and
a movable cam as C, controlled by the governor, so operating together that the
admission valve is opened at a predetermined point by the fixed cam and the point
of cut off is determined by the movable governor cam, the curve of the acting
surface of the movable cam being struck from the same centre as the said cam is
moved round by the action of the governor and the acting surface of the fixed cam
being also struck from this centre substantially as and for the purposes herein
described.
3. The particular engine governing gear herein before described with reference
to Figures 12 and 3 of the drawings.
4. The combination of fixed and movable cams with a drum or cylinder governor
substantially as hereinbefore described with reference to Figures 4 and 5 of the
drawings.

page_text: 5. The speed adjusting device comprising the rods e bell crank levers Q rod P
lever R and adjustable spring plunger T substantially as hereinbefore described
with reference to Figures 4 and 5 of the drawings.
Dated this 16th day of October 1895.
HERMANN KUHNE.