Improvements in and relating to Automatic Governors and Cut-off Valve-gear for Steam Engines.
Year: 1889

page_text: JUMI DIE
Improvements in and relating to Automatic Governors and Cut-off
Valve-gear for Steam Engines.
I, JAMES DANIEL GRAY, of 938, F. Street North West, Washington, District of
Columbia, United States of America, Inventor, 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 that class of automatic governors and cut offs, designed to
regulate the admission of steam, or other imponderable agent, in such a manner as to
render the rate of the engine constant through all the variations of the resistance
to be overcome, and designed also to so admit the steam at such times during the
quartering of the stroke as will best develope the efficiency of the engine.
My invention has for its object the adoption of means, simple and compact in form
and moderate as to its cost of construction, which will equalize the variations in
magnitude undergone by the driving couple in its stroke, which is accomplished by
gradually cutting off the steam as the driving couple advances toward one of the
points of its least efficiency, viz.: at the end of the stroke of the piston and upon
arrival at said point entirely closing the initial entrance, and as the driving couple
recedes from said point gradually opening said initial entrance until upon the arrival
of the driving couple at the quarter stroke of the piston, or the point of the greatest
magnitude or efficiency, the initial entrance is entirely opened admitting the full
pressure or head of steam.
My invention consists in a reciprocating rod which reciprocates loosely through a
connecting rod or arm, which latter has its other extremity secured by means herein-
after described, to the valve stem or eccentric rod of an engine, said rod has one of
its ends formed into a rack which engages with a pinion secured to the shaft which
actuates the valve admitting the steam to the steam chest. Interposed are two spiral
springs coiled about the reciprocating rod between. a weight or weights and the
connecting rod or arm secured to the valve stem or eccentric rod, said weight or
weights travelling or riding in guides. The two coiled springs may be increased in
resiliency by means of right and left screws.
I also when found necessary, employ a hydraulic cylinder provided with a delivery
pipe connecting or opening communication between the two ends of the cylinder,
the piston head of said cylinder being connected to the reciprocating rod.
The admission valve consists of a valve seat preferably flat in form, provided with
screw threads on its periphery which mesh with screw threads cut in a projection
cast with the casing, said seat describing or forming the half of a circle, the other
half of which is open for the entrance of the steam. The valve face is also formed
flat and constitutes slightly more than the half of a circle providing a lap which
forms a tight joint.
The valve shaft to which the face is rigidly secured passes loosely through the
seat and impinges against the point of an adjusting thumb screw.
The accompanying drawings represent a convenient arrangement of parts attached
to a stationary engine carrying out the object of my invention.
Figure 1 represents a side view of my improved governor and cut off attached to
a stationary engine; Figure 2 is a plan view of the same; Figure 3 is an enlarged
'view shown detached from the engine, of my improved governor and cut off;
Figure 4 is a vertical section through the admission valve casing; Figure 5 is a
detail plan view of the valve seat and valve face; Figure 6 is a detail view showing
the relative positions of the valve face and seat in full and dotted lines.
1 is an ordinary stationary steam engine, to the valve stem 2, of which is attached
by means of a friction clamp 3, or other suitable means, the connecting arm 4 which
latter has its upper extremity bossed, through which passes loosely the reciproating

page_text: rod 5 provided with weights 6 and 7 and spiral springs 8 and 9 coiled about said
reciprocating rod; one of each of the extremities of said spiral springs 8 and 9 being
secured to or impinging against the weights 6 and 7 and their remaining extremities
respectively impinging against or secured to each side of the boss 10 formed at the
loose connection between the reciprocating rod 5, and the connecting arm 4. I
also provide guides or travellers 11, for the said weights 6 and 7.
A portion of said
reciprocating rod 5 is formed into a rack 12, the teeth 13 of which engage in a
pinion 14 secured to the shaft 16 of the admission valve. I also when necessary
provide a hydraulic cylinder 17 through which the reciprocating rod 5 passes, and
a branch or delivery pipe 18 communicating with each end of the cylinder permitting
the liquid to alternately act as a stop or resistance against the piston head of the
cylinder, at each end thereof.
An arm or standard 19 suitably brassed to modify friction serves as a support and
guide for the outer operation of the reciprocating rod 5. The interior periphery of
the weights 6 and 7 where the reciprocating rod 5 passes through them and the length
of the same portion of said rod 5 are screw threaded at 20, 21, with right and
left threads respectively and the end of the rod may be provided with means by
which the said rod is rotated to increase the tension of the springs 8 and 9.
The reciprocating rod 5 may be formed in two parts and a union effected by
means of a coupling 22, so that the tension of the springs may be increased by means
heretofore described without disturbing the relative position of the rack 12 to the
pinion 14.
The admission valve consists of the casing 23 which is provided with a valve seat 24
forming the half of a circle, through which the valve shaft 16 passes loosely. The
valve face 25 secured to shaft 16 forms or describes slightly more than half of a circle
so that the lap 26 is formed, making a tight joint between the face 25 and seat 24
when the valve is closed.
The valve seat 24 has its periphery screw-threaded, which meshes with a screw
thread on the projection 27, cast with the valve casing.
The valve shaft 16 passes loosely through the hub 28 of the valve seat 24 and
impinges against the thumb screw 29.
The operation of my device is as follows:-
The reciprocating motion of the valve stem 2 of the engine is communicated to the
reciprocating rod 5 by means of connecting arm 4, the reciprocation of the said rod 5
being converted into a motion of rotation of the valve shaft 16 by means of the a
rack 12, and pinion 14, which motion of rotation is communicated to the valve face 25
causing the latter to assume varying positions relative to the seat 24 and consequently
alternately opening and closing the admission port in extent proportionate to the
throw of the reciprocating rod, which throw is dependent upon the tension of the
springs 8 and 9.
It will be seen that by the peculiar construction of the admission valve the steam
tends to keep the seat and face from each other permitting the ready opening of
the valve against pressure, it having been heretofore found necessary to admit
steam from the opposite direction in order to avoid the necessity of opening the
valve against said pressure. It will also be seen that the valve face and seat 4
being formed flat avoids the excessive cutting incident to the ordinary conical
valve. By means of the thumb screw, the valve face may be regulated relatively
to the seat.
I preferably adjust the pinion 14 relatively to the rack 12 so that at the beginning
of each quarter stroke the port of the admission valve will be open, as the driving5
couple of the engine recedes from the said point gradually closes the port of the
admission valve, so that when said driving couple arrives at the point of least
magnitude or efficiency, viz.: the end of the stroke of the piston the valve will be
closed.
As the velocity of revolution of the engine increases the resistance of the weights 6
and 7 becomes greater which in turn increases the resiliency of the springs 8 and 9,
thus shortening the throw of the reciprocating rod 5 and the relative width of opening

page_text: of the admission valve, and necessarily as the velocity diminishes, the throw of the
rod is increased with its consequent effect upon the admission valve.
In high speed engines it may be found necessary to use only one of the weights, or
the resiliency of the springs secured to stops alone may even be sufficient, but in
engines of a desired moderate speed, heavy weights and springs of great resiliency
will be needed, while in slow speed engines it will be found necessary to use the
hydraulic cylinder, each case depending upon its individual necessities.
The resistance of a suitable body is employed in my improved device instead of
the usual centrifugal force, and it is obvious that it is not necessary to develop the
force of resistance, as in the case of a centrifugal governor, that therefore, my
governor and cut off is much more sensitive at the working point, and therefore,
more efficient, at the same time being more compact in form and costing less in
construction. It will also be seen that I provide an admission valve flat in form
and capable of being readily opened against pressure and having only one port of
entrance.
Instead of connecting the connecting arm to the eccentric rod or valve stem of the
engine it may be found most desirable to provide an eccentric and connect its rod
directly to the reciprocating rod of the governor.
Having now particularly described and ascertained the nature of my
invention, and in what manner the same is to be performed, I declare that what
I claim is:
1. The combination with the admission valve of an engine, of an automatic governor
and cut off consisting of a weighted reciprocating rod, interposed adjustable springs
and means for converting said reciprocating motion of the rod to rotary motion of
the said admission valve, as set forth.
2. The combination of an admission valve, a reciprocating rod, interposed adjustable
springs, a stationary hydraulic cylinder serving as a resistance, and means by which
said reciprocatory motion of the rod is converted into rotary motion of the said
admission valve, as set forth.
3. The combination in an automatic governor and cut off, of an admission valve,
a pinion and weighted rack or rod, interposed spiral springs, said weighted rod being
loosely connected with the connecting arm of the valve stem, as set forth.
4. The combination in an automatic governor and cut off, of an admission valve,
a weighted rack and rod connected loosely to the connecting arms by means of
adjustable spiral springs, said connecting arm being connected to the valve stem of
an engine, as set forth.
5. The combination of a weighted rack or rod, having a reciprocating motion,
means for converting said reciprocating motion into rotary motion of an admission
valve which latter consists of a valve face and valve seat flat in form having a single
port of initial entrance and capable of being readily opened against pressure, as set
forth.
6. The combination of a weighted reciprocating rod having a portion of its length
formed into a rack, a pinion secured to the valve stem of the admission valve and
meshing with said rack, interposed spiral springs and a stationary hydraulic
cylinder for increasing resistance, as set forth.
Dated this 9th day of December 1889.
TC 10 fen me si no
1033.
JAMES DANIEL GKAY.
Jensen & Son,
77, Chancery Lane, London, W.C., Patent Agents.