Improvements in Duplex Steam Engine Attachments.
Year: 1891

page_text: Date of Application, 29th Sept., 1891-Accepted, 31st Oct., 1891
COMPLETE SPECIFICATION.
Improvements in Duplex Steam Engine Attachments.
We, EDGAR COURTRIGHT, Mechanical Engineer, CHARLES GRIFFITH DAVIES,
Manufacturer, and FRANK CLIFTON LANGLEY, Manufacturer, all of Benton
Harbour, in the County of Berrien, and State of Michigan, United States of
America, do hereby declare the nature of our 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 new and useful improvements in duplex steam engine
attachments; and consists in a certain construction and arrangement of parts, as
hereinafter fully set forth, the essential features of which are pointed out particularly
in the claims.
The object of the invention is to provide means for connecting the reciprocating
piston-rods of a duplex engine to a single crank on the main shaft thereof, in such
manner as to impart a continuous rotary motion to said shaft and overcome the
dead-centres of the crank; and to provide means for actuating the respective
cut-off valves of the cylinders, by a single eccentric on the main shaft of the engine.
This object is attained by the mechanism illustrated in the accompanying drawings,
in which;
Fig. 1 is a side elevation of a compound engine provided with our improved
features, the side of one cylinder being broken out showing piston therein.
Fig. 2 is an elevation of the converse side of Fig. 1, the column or supporting
frame being broken away on dotted line 1-1 of Fig. 1.
Fig. 3 is a plan view of Fig. 2.
While our improved features are shown in connection with a vertical compound
engine, they may be employed in duplex engines of other construction.
Referring to the letters of reference, A. indicates the pedestal or supporting
frame of the engine mechanism, on the upper end of which the cylinders B, B³,
are mounted.
The cylinder B is provided with a suitable piston indicated by dotted lines A¹
in Fig. 1, that is adapted to reciprocate therein, to which is connected one end of
the piston-rod C. The opposite end of said piston-rod being secured to a sliding-
head D adapted to travel on the guideway D", said head being in turn pivotally
coupled to one arm of the triangular beam E, by means of the link D.
The cylinder B' is provided with a piston B having one end of the piston-rod C¹
connected thereto, the other end of said rod C¹ is secured to the sliding-head M
adapted to travel on the guideway M'. The head M being pivotally coupled by
the link C to the adjacent arm of the triangular beam E, which is mounted at its
lower plane on the rock-shaft F that extends transversely across the pedestal or
frame A, its ends being journaled in cross-heads F¹ mounted in guideways F" in
the sides A of the frame, in which they are adapted to slide. The upper arm of
the triangular beam E is provided with a bearing-head E', in which is journaled the
wrist-pin G of the crank-arm G that is keyed on the end of main-shaft H, which
is journaled in the pillow-block P mounted on the pedestal or supporting frame, as
clearly shown in Figs. 2 and 3.
The pistons of the respective cylinders B, B', move simultaneously and in the
same direction during most of their stroke, when steam is applied thereto. The
valves of said cylinders being so set that the piston of one cylinder given a
slight "lead" over the other, as shown at B", and by dotted lines A¹ in Fig. 1, so
that when one piston is starting on its down stroke, the other will not have quite
completed its up stroke, which operation imparts a reciprocating motion to the
beam E, and causes its outer arms to oscillate. The cross-heads F¹ that support

page_text: the ends of the rock-shaft F on which said beam is mounted, sliding in the guide-
ways Fon the frame, and the upper arm of the beam E being coupled to the
wrist-pin G¹ of the crank-arm G of the shaft H, a continuous rotation is thereby
imparted to said shaft.
The employment of the triangular, reciprocating, and oscillating beam E, for the
conversion of a reciprocating into a rotary motion, conduces, in conjunction with
the simultaneously acting pistons, one of which working slightly in advance of the
other, to overcome the dead-centres of the crank-arm G. For it will now be
evident, that, when one of the pistons is rendered ineffective at the moment the
crank-arın is passing the point of dead-centre between its axis and the end of the
beam E to which the rod of said piston is coupled, the arrangement of parts is such,
that the other piston will be exerting its greatest leverage force to carry said crank
past said point, thus imparting a continuous and uniform rotation to the shaft H,
obviating the use of a fly-wheel.
The mechanism for operating the cut-off valves of the respective cylinders is
more clearly illustrated in Figs. 2 and 3, and consists in a triangular-beam I,
similar to the beam E of the engine. The upper arm of which is provided with an
eccentric-strap N that incloses the eccentric-head H' on the shaft H. Said beam I
at its lower plane being pivotally mounted on the pin 4 of the cross-head K adapted
to slide on the vertical guide-plates L bolted to the sides A" of the frame. The
horizontally opposite ends of said beam being coupled to the rods J, J, that operate
the slide-valves in the steam-chests of the respective cylinders, which is not shown
a's such matter will be readily understood.
•
It will now be apparent, that the throw of the eccentric-head H¹ will cause the
beam I to reciprocate, and will impart an oscillating motion to the outer ends
thereof to which the cut-off rods J, J¹, are attached, whereby said rods are actuated
to operate the slide-valves of the respective cylinders: The location of the
eccentric-head H' on the shaft H, respecting the position of the crank-arm G,
determines the action of the valves of the cylinders, in conformation with the
required action of their respective pistons.
As will now be obvious, the above described engine is simple of construction,
compact and durable; one that may be operated with a great saving in power, and
in which the pistons are given a great leverage force over the driving crank, which
crank, considering the two points of the application of the driving power thereto,
is at no time on a dead-centre.
Having now particularly described and ascertained the nature of our inven-
tion, and in what manner the same is to be performed, we do declare that what
we claim is ;
Claim 1. An engine attachment comprising a frame having a slideway thereon, and
a shaft journaled in said frame, combined with a triangular-beam having an eccentric
connection with the shaft, a cross-head on said way, said cross-head having a pivotal
connection with the triangular-beam, the cut-off rods attached to the oscillating
ends of said beam, substantially as specified.
Claim 2. In a steam engine the following combined elements; the main supporting
frame having guideways at the ends and at the sides thereof, two steam cylinders
mounted on said frame, a piston and piston-rod for each cylinder, the sliding-heads
attached to the piston-rods, the cross-heads FI mounted on the guideways at the
sides of the frame, the rock-shaft journaled in said heads, the triangular-beam
mounted on said rock-shaft, the links coupling said beam to the sliding-heads of the
piston-rods, the main shaft, the crank thereon, the triangular-beam being coupled
to said crank, the cross-head K mounted on the guide-plates of the frame, the
triangular-beum journaled on the pin of said cross-head, said beam having an
eccentric coupling with the main shaft, the cut-off rods coupled to the free ends of
said beam, substantially as specified.
Claim 3. In an engine the combination of the supporting frame, the main shaft
cárry.úg a crank, the vertical guideways F", the cross-heads mounted thereon, the

page_text: rock-shaft journaled in the cross-heads, the triangular-beam mounted on said rock-
shaft said beam baving connection with the crank of the main shaft, the horizontal
ends of said beam carrying a link, said links being also coupled to the sliding-heads
mounted on the guideways of the main frame, the cross-head K, the guide-plates
supporting said head, the triangular-beam journaled on said head, and having the
eccentric connection with the main shaft, the free horizontal ends of said beam
adapted to operate the cut-off rods, substantially as set forth.
Claim 4. An engine attachment consisting of the following combined elements;
a shaft having a crank, a triangular-beam having one of its extremities journaled
on said crank, the central point of its horizontal member having a sliding bearing,
a second triangular-beam, having one of its extremities eccentrically coupled to said
shaft, the central point of its horizontal member having a sliding bearing, substan-
tially as shown.
Dated this 29th day of September 1891
ALLISON BROS.,
Agents for the Applicants.