Improvements in Steam Engines.
Year: 1894

page_text: Date of Application, 11th Dec., 1394--Accepted, 16th Feb., 1895
COMPLETE SPECIFICATION.
Improvements in Steam Engines.
1, WILLIS DURWOOD SHERMAN, of 85-93 Ninth Street, in the City of
Brooklyn, State of New York, U.S.A. Mechanical 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 :-
My invention relates to improvements in steam engines, by providing for the
same an "automatic steam counterbalance"; that is to say, means consisting in an
automatic variable lead, whereby a steam cushion is formed in advance of the
piston, in order to counterbalance the inertia of the piston and connected parts as
the piston nears the end of its stroke, avoiding the violent shock attendant upon
the reversal of the motion of the piston when running at variable speed, this steam
cushion being automatically controlled through the variable speed of the main
shaft of the engine.
The invention proceeds upon an automatic variation of the lead of the valve
which controls the main cylinder, so that as the speed of the engine varies the
lead advances automatically and admits steam in front of the piston at a pro-
portionately earlier or later part of the stroke, thereby forming an automatic
steam cushion of greater or less extent as the speed of the engine tends to increase
or decrease, producing an automatic counterbalance and absence of shock. The
invention is not a governor in the ordinary sense of the word, and is not dependent
upon the opening or closing of the main throttle valve, but operates entirely
through the variation in the elastic resistance interposed in front of the piston by
automatically regulating the earlier or later admission of the steam before the end
of the stroke.
I have also adapted the invention to port-reversing engines. The use of such
engines has been limited by the fact that owing to their mode of operation it has
heretofore been impossible to provide the main valve with any lead. My invention
has furnished the means of providing the lead for such engines whereby they are
adapted not only to hoisting but to a variety of other purposes.
The invention can be operated by various special constructions, several of
which are hereinafter described.
C
Referring to the drawings which accompany the Specification to aid the
description:
Fig. 1, is a representation of one form of my device applied to a steam engine;
Fig. 2, is a view of the parts from above;
Fig. 3, is an enlarged detail partly sectioned, showing my preferred means
of affecting the variation in the lead through the varying velocity of the main
shaft.
Fig. 4, is an elevation on a large scale of substantially the same device as is
shown in Fig. 1.
Fig. 5, is a sectional detail illustrating by solid and dotted lines the position of
the valve corresponding to the positions of Figs. 3 and 4.
Fig. 6 is a side elevation, partly sectioned, of the application in one form of my
invention to a port-reversing engine;
Fig. 7 is a plan view, partly sectioned, of the same engine;
Fig. 8 is a detail of the eccentric, collar, and gearing for shifting the eccentric.
The lagging weights are removed for the sake of clearness;
Fig. 9 is a side elevation; and

page_text: Fig. 10, a section of a modification of the device;
Fig. 11 is an elevation of still another modification of the device;
Fig. 12 is an elevation of that form of the device consisting of air resisting
blades applied to a port-reversing engine;
Fig. 13 is a face view on a larger scale of the blades, and showing certain other
parts in section.
Referring to Figs. 1, 2 and 4, A, being the main cylinder, B the main driving
shaft, and D the piston rod of a hoisting engine of any suitable description;
E represents, the drum and its gearing, F is the valve chest on the cylinder and
G the slide valve, H being the valve rod and I the eccentric set loosely on the
shaft B and provided with a collar i, which has an arm j, against the face of
which bears an end of a lever K, piroted on a standard L which is keyed on
the shaft B. The other end of said lever K has a weight k. A rod m pivoted to
the lever K at n, works through a hole in the arm j, and has a spring o
coiled on
its outer end, p, being a butterfly nut to regulate the tension of the spring.
Suppose the valve set for a given lead as indicated by the cross-hatched valve
Fig. 5, then the weight k, will tend to fly outward, thereby pushing the arm j,
correspondingly, increasing the lead of the valve G, and allowing the steam to
enter the cylinder A, in front of the piston B¹ and form a steam cushion at an
earlier part of the stroke. Said steam cushion forms an automatic counter
balance to the inertia of the piston and connected parts and prevents vibration of
the engine.
Referring to Fig. 3 the collar i, is slotted at ?, k², the edges of the slots being
bevelled. The main shaft B has a corresponding- slot b, the sides of which are
bevelled. Through the said slots b, and j, k, work rods m³, n³, the ends of which
pass through holes in the weights O', P. The said rods m³, n³, have wedge
surfaces m³, n³, respectively, adapted to bear on the walls of the slots, k³. The
rod m³ is connected with the weight O' through the compressible spring Q, and the
rod is similarly connected with the weight P1 through the compressible
spring R. Also the rod m² has a rigid connection with the weight P¹ by bolt and
nut, and the rod a similar connection with the weight O¹.
Suppose the speed of the engine to increase, then the centrifugal force tending to
throw the weights O P outward increases, and said weights O' will draw the
sliding rods m³, n² outward and the wedges will shift the eccentric ahead. The
aforesaid springs Q and R draw the weights O P inwardly as soon as the speed
of the main shaft decreases, thereby revolving the collar i and eccentric I in the
reverse direction, and diminishing the lead and the steam cushion in advance of
the piston.
Referring to Figs. 6 to 8.
A being the cylinder, B² the piston, C' the connecting rod, D¹ the valve
chest, E the main valve, F' the connecting rod of the valve and G¹ the eccentric
on the main shaft H¹ of a port-reversing engine.
The eccentric G₁ is formed integral with the collar g, which has a working fit
on the main shaft H, and is provided with teeth j, k, arranged on opposite
extremities of a diameter of the main shaft H'. I is a disc keyed on the main
shalt H', adjacent to the collar g, levers L³, L' are pivoted on said disc at,,
and provided with lagging weights M³, M³. The inner ends of said levers L, L
are provided with teeth which mesh with teeth j, k, of the collar g. N³, N,
are arms of the levers L, L, respectively, and pivotally connected with
rods 0, 0, which rods work through eyes in lugs fixed on the disc 1.
The inner ends of said rods 0, 0, are preferably threaded in a sleeve as indicated
in Fig. 6 to facilitate the assembling of the parts, and also to vary the tension of the
spring, and said rods O³, 0³ are shouldered to bear against the washers p', p³,
between which is a spring R, coiled loosely, around the rods 0 0³, and sleeve.
The said parts are applicable to a reversing engine of any kind, and I therefore
describe their application generally before passing to their combination with the
port-reversing engine.

page_text: Suppose the engine to be running in a direction indicated by the arrow, now the
lagging weights M2, M3, will tend to fall behind the main shaft H' and will cause
the levers L, L, to shift the eccentric G₁, and increase the lead of the main
valve E', thereby admitting steam in front of the piston B2, and forming a steam
cushion to overcome the inertia of the piston and connected parts and reduce
the vibration of the engine at the end of the stroke. The higher the speed of the
engine, the greater the tendency of the lagging weights M2 M to fall behind the
shaft, and the greater the proportionate part of the stroke at which the steam
cushion is formed.
Referring to the special application of the device to the port-reversing engine,
S is an auxiliary balanced valve or throttle, operated by the rod, s, working through
a stuffing box s¹ and connected with lever S. Said lever preferably provided
with a rod and spring X, set to always restore the valve S to the middle
position, as shown, in Fig. 6, wherein both ports of the cylinder A' are closed, and
a steam cushion is formed on each side of the piston B, which cushions act as a
brake.
The said valve S, has a through and through steam way s2, and is provided with
an annular port t, which connects with the exhaust port t', and, according to the
position of said valve S, also with the ports t', 13, t, said port t being a branch of
the port. Now, supposing the engineer throws the valve S to the right opening
the port, and connecting port t with the annular port t, the steam will pass to the
right end of the cylinder A', by means of the ports t², t, moving the piston to
the left, and the engine will continue to run in a corresponding direction as long as
the valve S is retained in that, position. If the operator desires to "brake" the
engine, he allows the lever S to go to the middle position and immediately the
ports t, are closed by the valve and a steam cushion is retained in the cylinder A'
on each side of the piston B2, and the engine arrested.
To reverse the engine, the operator throws the valve S to the left. The steam
now enters the port, the exhaust ea of the valve E', and goes thence through the
port to the left end of the cylinder A¹ throwing the piston B2 to the right, and
the engine continues to run in the corresponding direction as long as the valve S is
retained in that position.
The conditions of the operation of such port-reversing engines have heretofore
prevented giving any lead to the valve E¹, the said valve requiring to be set
exactly in the middle position in order to start the engine. But my invention has
provided the means of introducing a variable lead on such engines, because,
although when the engine is at rest my device for varying the lead is held at the
middle position by the spring q² and there is no lead to the valve El, yet, as soon
as the engine begins to run, my device introduces a variable lead in the manner
herein before described.
The drawings show the engine provided with two cylinders, the connecting rods
of which are connected with cranks at right angles to each other in the well known
manner.
In Fig. 9, the levers L, L³, are shown provided with cams which bear on
springs Y, Y', that are held in position by bars y, y', provided with lugs, said
bars, y', clamping the 'springs 'Y, Y', against the main shaft H', by bolts as
shown.
The shaft H' is preferably furnished with an annular groove, *, for the
bolts, as shown. The said levers L, L³, are each connected with the
eccentric G', by means of pins 4, 7, set in the face of the eccentric, and working
in slots in the cams 1, 1. Said springs Y, Y', normally hold the lagging
weights M, M³, in the middle position, but as soon as the main shaft H' attains a
determined speed, the inertia of the weights M³, M³, causes them to deflect the
eccentric, G, correspondingly. The weights M³, M³, act irrespective of the
direction in which the shaft is moving.
Referring to Fig. 11, the levers L, L, have arms n', n³,
which are
respectively,
connected with the eccentric collar by means of links y', g, respectively. The

page_text: lagging weights M³, M³, are represented in this fig. as adjustable on the said
levers L, L, by means of set screws m², m³. Evidently the said lagging
weights M, M³, will deflect the eccentric G¹, in the manner hereinbefore described
according to the direction and speed of the shaft H*.
Referring to Figs. 12 and 13, A' being the cylinder, F, the connecting rod of
the valve, and G, the eccentric on the main shaft H', the counterbalance is applied
in the following manner:
The eccentric G', is integral with the collar, which has a working fit on the
main shaft H, and is provided with teeth 1, 4, preferably arranged on opposite
extremities of a diameter of the main shaft H'.
18 is a disc keyed on the said main shaft H adjacent to the collar 9. In said
disc 1 is pivoted at 3,, the levers L, L, to which levers are secured in any
suitable manner the blades M, M. The drawings show the levers L³, L, each
provided with weights and the aforesaid blades M, M secured to the said
weights by means of bolts and slots m, mo, respectively, but I cau dispense
with the said weights and connect the said blades directly with the levers L, L.
I prefer to form each blade in two pieces, which may slide over each other, so as
to increase the effective surface when desired. The inner ends of said levers L³, L',
are provided with teeth which mesh with the teeth, k, of the collar 4. Said
levers L, L, are also provided with arms N, N°, which are pivotally connected
with rods O, O' which work through eyes in lugs q, q, fixed on the disc 1°. The
inner ends of said rods 08, 0%, thread in a sleeve O Said rods are shouldered
to bear against washers between which is a spring R', coiled loosely around the
rod 0, 0, and sleeve 010. The tension of said spring is regulated by turning
the sleeve (10 and said spring is so set as to normally hold the eccentric in
such position that there is no lead to the valve of the port-reversing engine.
The device operates in the following manner :-
Assuming that the main shaft be running in the direction of the arrow (Fig. 12)
the resistance of the air will cause the said blades M, M, to lag behind the main
shaft indicated by the small arrows adjacent to the blades and oscillate the
levers L, L, about their pivots, in the direction of the air pressure and the
said levers will rotate the eccentric G, on the main shaft correspondingly, and
thereby increase the lead of the main valve producing a steam cushion in front of
said piston, which automatically counterbalances the inertia of the piston and its
connected parts, and prevents vibration. If the engine be revolved in the
opposite direction, the same effect will be produced, the air pressure on the
blades M, M, now oscillating the said levers L³, L', in a direction reverse to
the motion of the said shaft as before, and giving the eccentric a lead in the
opposite direction.
The effect of the weights, is to energize the motion of the blades MB, M³, for
the inertia of the said weights will manifestly cause them to lag behind the
main shaft, and this tendency will be added to the resistance of the air on the
blades M³, M°.
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 steam engines, the combination of the cylinder, piston, main shaft,
eccentric movable thereon, and set to a normal position, main valve, and weights
revolved by the main shaft and adapted to shift the eccentric so as to increase
the lead of the main valve, when the speed of the engine increases above the
normal.
2. The combination in a steam engine, with a cylinder, piston, shaft, valve and
eccentric, of weights arranged to be thrown out from the centre of the main shaft
as the velocity increases and adapted to co-operate with surfaces which actuate the
eccentric for the purpose of varying the lead of the valve according to the speed of
the piston.

page_text: 3. The combination in a reversible steam engine, of a cylinder, piston ports,
main valve controlling said ports, shaft, eccentric, and devices revolved by said
shaft and adapted to automatically increase the lead of the main valve as the speedl
of the engine increases and automatically decreases the lead of the main valve as
the speed of the engine decreases-in either direction.
4. The combination with a port reversing engine of devices for automatically
varying the lead of the main valve according to the variation of the speed of the
engine in either direction.
5. The combination in reversible engines, of a cylinder, piston, main valve, shaft,
eccentric, and lagging weights revolved from the main shaft and adapted to shift
the eccentric and vary the lead of the main valve according to the variation in the
speed of the engine in either direction.
6. In steam engines, air resistance blades operatively connected with the main
shaft and with the eccentric, for the purpose of automatically varying the lead of
the main valve according to the speed of the engine in either direction.
7. The combination with the main shaft, eccentric, and valve, of slotted blades
adapted to expose greater or less effective surface to the air, for the purpose of
shifting the eccentric and varying the lead of the valve according to the speed of
the engine in either direction.
Dated this 4th day of December 1894.
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent.