IMPROVEMENTS IN ROTARY ENGINES
Year: 1884

page_text: COMPLETE SPECIFICATION.
I, JOSIAH Dow, of Lowell in tho County of Middlesex and State of Massa-
chusetts, one of the United States of America, a manufacturer, do hereby declaro
the nature of my invention for IMPROVEMENTS IN ROTARY ENGINES, 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 improvements in duplex crank piston steam engines
and it is carried out as follows, reference being had to the accompanying drawings
where Fig 1 represents a side elevation of the improved engine; Fig 2 an end
view seen from a in Fig 1; Fig 3 a central longitudinal section on the line A B
shown in Fig 2; Fig 4 a cross section on the line C-D shown in Fig 3; Fig 5 a
cross section on the line E-F shown in Fig 3; Fig 6 a side elevation of one of
the intermittently rotary valves for admitting steam to the cylinders; Fig 7 is a
section of the same on line G-H in Fig 6; and Fig S ropresents two detail views
of the movable ring for actuating the valve discs to close the rotary valves.
Similar letters refer to similar parts.
In the drawings a is the piston shaft to which the duplex crank pistons aro
secured; said shaft is located in suitable bearings in the ends of the shell or
cylinder, and has attached to it a spur gear a¹ that gears into a gear b¹ of equal
diameter and of equal number of teeth, the latter being secured to the shaft b to
which the rotary abutments are secured.
c is the shell or steam cylinder cast in ono piece with the abutment chamber c¹
and base c as shown, and c³ is a division wall cast in one piece with cylinder c, c';
said wall is arranged midway between the ends of shell c, c¹ and by its use the
said shell is divided in two equal compartments U and V as shown in Fig 3 each
of such compartments containing a rotary piston and corresponding abutment
cylinder.
& represents the head secured by means of screw bolts or equivalent or well
known devices to the right hand end of shell c, d as shown in Fig 3 and it has
perforations through which the respective shafts a and b project outside of said
head. In one piece with head d I prefer to cast the outwardly projecting
brackets and the former serving as a support for the bearing all on shaft a,
such bearing having a cap d for holding a" in place; a³ is a packing surrounding
the shaft aut the inuer end of stuffing box a¹¹. In a similar manner the bracket du
supports the bearing bu for the shaft b and is provided with cap d'and stuffing b³..
F

page_text: To the opposite end of shell c, c' is secured the head e in one piece with which
is cast or otherwise secured to it the outwardly projecting valve chamber e¹ having
a central bearing sleeve e provided with stuffing box and stuffing & for the
piston shaft a as shown in Fig 3. In its lower end the head e has an outwardly
projecting bracket e supporting the bearing b and its cap e for the abutment
shaft b. 6 is the stuffing for shaft 6 in the head e as usual.
On the shaft a, within the compartment U, is secured the rotary.cylinder f
provided with annular tapering grooves at the junction of its ends and curved
surface which grooves contain the tapering packing rings f¹, f¹ made of suitable
material for the purpose of effecting a steam-tight connection between said cylinder
and the ends of its compartment U in which it rotates. In one piece with said
cylinder fis cast the radially projecting piston f" made tapering from its base
outwards to insure proper strength and made to fit closely against the sides and
curved portion of compartment U and provided at such place with a packing ƒ³
made of suitablo material resting in a corresponding groove in the sides and outer
end of said piston as shown.
To the shaft b, directly below the cylinder f, is secured the abutment cylinder g
which is the same diameter as the cylinder f, and said cylinders are held in contact
with each other so as to allow the one to roll on the other with equal surface
velocity, and at the same time preventing the steam from escaping between them;
directly opposite the piston 11 is made in the abutment cylinder g, a curved cut away
portion to permit the piston f" to pass by the cylinder g as they rotate together
in opposite directions. The curvature of the cut away portion g' is such as to
keep the piston f" in immediate contact with it so as to prevent escape of steam
during such passage of the said piston. The cylinder g is provided with webs g³, g³
on the ends of the cut away portion g¹, between which webs the piston fll enters
during its passage into said space g³ to still further prevent the escape of steam at
this point.
11
At the junction of the ends and curved part of abutment cylinder g, I make
tapering grooves into which are fitted the tapering packings g, g made of suitable
materials to effect a tight connection between said cylinder and the interior of the
chamber in which it revolves.
I prefer to make the abutment cylinder g, with a central hub 95 secured to shaft b
and radial arms gº as shown. y' is a semicircular space between the exterior of
abutment cylinder g and interior of abutment chamber c¹ adapted to receive steam
and thus to equalize the pressure in compartment U, and causing the cylinders f, g
to be held in close contact against each other during their rotation and also to aid
in lubricating the said abutment cylinder in its motion.
gg are packing rods located in corresponding grooves 9º, g³ in the upper sides
of abutment chamber as shown in Fig 4, such grooves being made deep enough to
contain springs if desired to hold said packings against the abutment cylinder to
effect a close joint at such place. Behind the cylinder f is secured to the shaft u
the secondary cylinder h, constructed in the same manner as cylinder f and secured
to it in a suitable manner. The cylinder h is located in compartment V and is
provided with tapering packing rings h' h¹ projecting piston ¹ having packing h³
like the corresponding parts on cylinder f, with this difference that the piston f"
is located in a diametrically opposite direction to the piston h¹ to effect a perfect
balance of said cylinders. Below the cylinder in the corresponding abutment
chamber is located on the shaft b the abutment cylinder i of equal diameter with
said cylinder h, and provided with curved cut away portion i¹, webs i³, 1³ tapering
packings, central hub ³, radial arms iº, semicircular space i, packings and
grooves in a similar and corresponding manner to those on abutment cylinder g,
with this difference that the cut away portion i¹ is located in a diametrically
opposite direction to the cut away portion g' on cylinder g, to effect a perfect
balance of said abutment cylinders. e' is the steam inlet to the valvo chamber e'
as shown in Fig 3 from which the steam is conducted back of the respective
pistons f", has follows:

page_text: : Through the cylinder fis made two longitudinal conduits and the former
leading to the cylindrical valvo in cylinder f, and the latter leading to the
corresponding cylindrical valve in cylinder h. and are the valve stems
respectively for the valves and as shown in Figs 3 and 4.
-
M is a flanged collar or bearing piece secured to the outer end of cylinder f and
adapted to serve as a bearing for the outer ends of valve stems, as shown in
Fig 3. f and are steam channels in the respective cylinders fand h leading
from the respective valves and 7 directly behind the respective pistons f" h" as
shown in Fig 4, by means of which the steam pressure is conducted back of the
pistons f, in the respective compartments U and V.
The cylindrical steam valve k has three communicating side openings k³, 1³, k³
with preferably a central core for strengthening it as shown in Fige 6 and 7, and
tho valve stem has attached to its outer end a single disc k which is provided
on its inner face with three valve opening pins or projections k, k, k³ one of which
is actuated by the cam groove m in the projection m¹ on the stationary ring m
that is secured to the valve chamber bearing sleeve e¹¹ as shown in Figs 3 and 5
for each time that the cylinder f completes its revolution and thus causes the
valve to be turned one sixth of a revolution around its axis to admit steam
through channel ft. The disc is also provided on its outer face with three valve
closing pins or projections k, k, one of which is actuated by the cam groove n¹l
in the projection n' on the movable ring n that is loosely supported and made to
turn around the valve chamber bearing sleeve e as shown in Figa 3 and 5 for each
time that the cylinder f completes its revolution and thus causes the valve k to be
turned one sixth of a revolution around its axis to shut off the steam from passing
through channel f. An annular groove m³ is made in the ring m to permit the
disc to turn around freely when the shaft a and cylinder fare rotated.
The pins ko, ko, " on the inner face of the disc are located alternately with the
pins h, k, on the outer face of the disc, that is the pins on one side are located
midway between the pin on the opposite sido of the disc as shown in Fig 5.
After the disc ' has been revolved one sixth of a revolution and its valve k held
open long enough to admit a sufficient quantity of steam through the channel f*
behind the piston f" the pin le that is laying on the movable ring i passes through
the cam groove in the projection n' on the ring n causing the disc and its valve
to be revolved one sixth of a revolution in the same direction as when said valvo
was opened thus closing the valve. The duration of time in which the valve k
remains open depends upon the relative position of the projections m³ and n¹ and
their cam grooves m¹ and n" on the stationary ring m and movable ring n and
the positions of these parts may be varied by the following mechanism. The
ring n is toothed on its outer surface and into it is geared the worm o secured to
worm-shaft o¹ located in suitable bearings in valve-chamber e¹ as shown in Figª 3
and 5.
To the outer end of worm shaft o² is secured the small bevel pinion o¹¹ that gears
into the bevel gear p¹ secured to shaft p located in bearings in the bracket P
secured to valve chamber e' as shown in Figs 1, 2 and 3.
:
The shaft p is rotated more or less in either direction to cut off the steam at any
desired part of the stroke or to maintain any desired and uniform speed of the
engine by the following mechanism to the main shaft a is keyed the eccentric
block q surrounded by the loose ring q¹ having an upwardly projecting rod q
attached to it, the upper end of which plays loosely in the sleeve r forming a part
of the hub r loosely supported on shaft p as shown in Fig 3. To the hub is
made an upward extension 11, having hinged to it loosely the two pawls 3 and 7ª
as shown in Figs 2 and 3. Directly below pawls and is secured on shaft p
the spur or pawl-gear S. To the shaft p is hinged loosely the shield plate t that
overlaps the upper portion of gear S and may be swung on the said shaft p to the
right or left by its connection to any ordinary governor so as to permit one of the
pawls or, only to engage at one time into the teeth of gear S as shown in
Fig 2: t is a downwardly projecting balance weight cast on to the lower side of

page_text: the hub on shield plate t as shown in Fig 1, 2 and 3, such balance weight being for
the purpose of balancing the plate or shield in its rotary motion on shaft p;
11 is a short lever attached to or made in one piece with shield t or its hub or
balance weight t' which is to be connected in any suitable manner to any suitable
governor..
This speed regulating mechanism acts as follows; by the eccentric q, q¹ rod q¹¹
and sleever, the pawls ³, aro oscillated on top of gear S continually, the shield t
being however during this motion of pawls ³, so worked and held in position by
its connection to the governor lever u that only one pawl at one time or neither of
them acts on the gear S, the other one or both sliding loosely on top of shield tas
shown in Fig 2 so as to cause the gear S to turn in one direction according to
whether the governor and engine runs above or below its normal speed. As the
gear S is turned it imparts motion to the loose ring n, by the connecting mechanism
as described and said ring is thereby automatically turned around the bearing
sleeve e¹¹ to cause the cam groove n on its projection n¹ to act on the valvo
- closing pin or projection which is laying and moving on the ring n and to
thereby turn the cylindrical valve k, one sixth of a revolution so as to cut off tho
supply of steain to piston f" at any desired position of its stoke or revolution as
may be desired.
In a similar manner to the valve k, the valve has attached to its valve stem (11
on the outer end thereof the single disc having valve opening pins or projections
1³ 15 1³ on its inner face and also valve closing pins or projections 70 70 70 on its outer
face as shown in Figs 3 and 5, the valve has like the valve k three communicating
side openings 13, 13, 13 to permit the steam to pass from conduit through the
valve and conduit or channel into the compartment V back of the piston kl.
The valve has like the valve ka central coro to strengthen it. The valves k and
are made to rotate intermittently in one and the same direction by the opening
and closing mechanism as above described.
Y is the exhaust opening leading from compartments U and V, such exhaust
may be common to both of said compartments, or it may be divided in two exits,
one for each compartment if so desired. K is the hub of the disc and L is the
hub of the disc .
The operation of my improved engine is as follows:
Steam being admitted through steam inlet e into valve chamber el passes
through steam conduits ¹ and to valves and and out through openings f, h*
into the respective compartments U and V and back of pistons f", ". Fig 4
shows the position of piston f" and its corresponding abutment cylinder g at the
time of admitting steam through opening f; the piston is then diametrically
opposite and may be pressed onward by live or expanded steam as may be desired.
The steam in advance of the respective pistons f", his free to pass out through
exhaust opening Y. During the rotation of pistons f", h" and their respectivo
abutment cylinders g, i the valves and are intermittently rotated in a constant
direction by the opening and closing rings m, and n, their respective projections m²
and n having the cam grooves m¹ and n and the opening and closing cam disks
on the valve stems as herein above set forth and described, the whole of the
mechanism being balanced properly so that the engine may be run at a very quick
speed without causing any noise or pounding and with a minimum of frictional
resistance.
The driving shaft a may be supported outside of the shell or case c, c¹ in suitable
bearings or pillow blocks, and be provided with a suitable fly or balance wheel in
the usual manner, such devices being however not shown in the drawings.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. In a steam engine the shell c, o², heads d, e, the shafts a, b, equally geared
together in combination with diametrically opposed cylinders and pistons ƒ, ƒ", h, h¹¹,

page_text: outer end of hoad e into which the stean is admitted through the steam supply
pipe situated upon and through the said steam chest e¹ as described.
2. In a steam engine the rotary cylinder f and its piston f" combined with
abutment cylinder g of equal diameter with cylinder f, the cut away portion g¹ to
permit passage of piston f" and curved steam space g' on the interior of abutment
chainber into which the steam passes from the main cylinder for the purpose of
pressing the abutment cylinder g against and securing perfect contact with the
rotary cylinder fas described.
3. In a steam engine the rotary cylinder fand its piston f" in combination with
an abutment cylinder of equal diameter made skeleton fashion with hub g³,
arms go, side webs g³, g³ and having cut away portion g' substantially as described.
4. In a steam engine a rotary cylinder having arranged within it a cylindrical
valve k, with side openings ³,,, adapted to rotate in a continuous intermittent
direction around its axis to deliver and cut off the supply of steam as set forth.
5. In a steam engine the rotary cylinder ƒ having arranged within it the
cylindrical valve & in combination with the disc secured to the valve stem "
said disc being provided with the pins or projections ko, k, k to operate with the
stationary ring m its projection m¹ and cam groove m" for the purpose of
automatically opening the said valve as set forth.
G. In a steam engine the rotary cylinder f having arranged within it the
cylindrical valve upon the stem of which is arranged the disc * having the
pins or projections,, in combination with the adjustable ring n its projection
n¹ and cam groove n for the purpose of automatically closing said valve k as set
forth and described.
7. In a steam engine the steam cut off mechanism as described consisting of
eccentric q its ring q¹ and rod q" rocking piece 71, 711 with its sleeve the hinged
pawls 2, 74, shield plate t connected to the governor and provided with a counter
balance t', the gear S secured to the shaft p, the bearing bracket P and intermediate
connecting mechanism substantially as described from shaft p to the loose ring n
as and for the purpose set forth.
8. In a steam engine the rotary cylinder f having a steam passage or passages k¹
located between the axis and outer periphery of said cylinder and communicating
with the steam passage f* located behind the piston f" as set forth and described."
9. In a steam engine the movable ring or collar n geared to the worm shaft o'
for the purpose of adjusting the point of cut off by the action of the governor as
set forth and described.
10. In a steam engine the rotary cylinder f, shaft a and flanged bearing piece M
carrying the valve-stem and its single disc having the opposite alternate
pins, upon it in combination with the stationary ring m and its opening
device m¹, m and the movable ring n and its closing device n³, n¹¹ as and for the
purpose set forth.
11. In a steam engine the bearing picce M the valve stem and disc in
combination with the bearing sleeve having flange v located between the outside
of bearing piece M and hub K of the disc as and for the purpose set forth.
Dated this 11th day of November 1884.