IMPROVEMENTS IN ROTARY ENGINES AND IN THE REVERSING GEAR TO BE ADAPTED THERETO, PARTS OF WHICH IMPROVEMENTS ARE APPLICABLE TO OTHER ENGINES
Year: 1877

page_text: LETTERS PATENT to Richard Hodson, of Abbey Road, Saint John's Wood, in
the County of Middlesex, Civil Engineer, for the Invention of "IMPROVEMENTS
IN ROTARY ENGINES AND IN THE REVERSING GEAR TO BE ADAPTED THERETO,
PARTS OF WHICH IMPROVEMENTS ARE APPLICABLE TO OTHER ENGINES."
Sealed the 22nd February 1878, and dated the 24th August 1877.
PROVISIONAL SPECIFICATION left by the said Richard Hodson at the Office
of the Commissioners of Patents on the 24th August 1877.
RICHARD HODSON, of Abbey Road, St. John's Wood, in the County of Middlesex,
Civil Engineer.
"IMPROVEMENTS IN ROTARY ENGINES AND IN THE REVERSING
GEAR TO BE ADAPTED THERETO, PARTS OF WHICH IMPROVEMENTS ARE APPLICABLE
TO OTHER ENGINES."
This Invention relates to various improvements upon an Invention of improve-
ments in rotary engines for which I obtained Letters Patent, dated 22nd December
1875, No. 4458.
The present Invention has for its main object to so construct and arrange the
parts of the engine that the piston rod which forms the main driving shaft of the
engine may be connected with the shaft to be actuated (for instance, the shaft of a
stern propellor), in such a manner that the latter may be driven in either direction
and quickly reversed without reversing or changing the direction of rotation of the
pistons in the working cylinders. To this end the piston shaft is so mounted in
its bearings that it is capable of being moved longitudinally therein to a limited
extent.
The cam-shaped pistons (of which there are, by preference, two working in
separate chambers formed by dividing the cylinder into two equal parts by means
of a central partition) are not keyed fast on to their shaft, but are simply mounted
thereon, and are connected thereto by means of a feather fixed in the shaft. This
feather enters a groove formed in the central hole or boss of the piston, so that the
shaft with its feather is free to move longitudinally in the piston, or the piston on
the shaft, but yet the shaft always revolves with the piston. Both pistons are
CD 31

page_text: mounted in the same way on the shaft, and one end of the piston shaft turns in a
kind of cylindrical thrust block which is moveable, and works steam-tight in a
cylindrical bearing cast on the cylindrical head. To the outer end of this moveable
thrust block is connected a hand lever, which is mounted on a fulcrum pin fixed
on the foundation plate of the engine.
The stem of the rotary or oscillating valve which admits the steam to the
cylinder is also connected to this hand lever, so that when the hand lever is moved
it will move the piston shaft longitudinally in the pistons, and at the same time
will move the rotary valve in the same direction. On to the other end of the piston
One side
shaft is keyed a male friction clutch, made in the form of a double cone.
of this clutch takes into a conical annular groove formed in the face or side of a
bevil wheel mounted loosely on the piston shaft, and is free therefore to revolve
thereon in either direction. The other side of the conical clutch takes into a similar
conical annular groove made in a cylindrical block mounted on the end of a pro-
peller shaft or other shaft which it is desired to actuate.
The cylindrical block is not keyed fast on the propeller shaft, but is connected
thereto by an inclined feather, which enters an inclined groove formed in the boss
of the cylindrical block, so that the latter, although obliged to rotate with the
propeller shaft, is capable of an endway motion thereon, but is kept in contact with
the chuck by a spring placed behind it.
.
Behind the cylindrical block, and keyed fast on the propellor shaft, is another
bevil toothed wheel, and both these bevil toothed wheels gear into an intermediate
idle wheel of the same kind.
It will now be evident that if the piston shaft be pushed forward by means of
the band lever, so as to force the male clutch into the annular conical groove of the
cylindrical block, the propellor shaft will be driven in one direction; but if the
piston shaft be drawn back, so as to bring the other side of the clutch into gear
with the bevil pinion on the piston shaft, it will (through the bevil gear) impart
motion to the propeller shaft in the opposite direction, and if by bringing the hand
lever into a vertical position, the clutch be placed midway between the two parts,
no motion will be communicated to the propeller shaft; and, moreover, the engine
will not continue in operation inasmuch as the steam will be cut off from the
cylinders. If the hand lever be moved a little on one side of the vertical position
a sufficient quantity of steam will be admitted to the cylinder to drive the engine,
but the propellor shaft will not be actuated inasmuch as the clutch will not be in
gear.
Instead of working the male clutch by moving the piston shaft endways by
means of a hand lever as already explained, a lever may be adapted direct to the
male clutch, so as to move the same in or out of gear without moving the piston
shaft.
This arrangement will be particularly applicable to engines constructed according
to my former Patent, in which the pistons are keyed fast on to the piston shaft.
Although I prefer to use two cylinders and pistons under ordinary circumstances,
it will be obvious that three or more cylinders may be used in combination, as
would be required if the engine is intended to work at high or low pressure by
exhausting from one cylinder into another.
In order to vary the speed of the engine the oscillating valve, which controls the
supply of steam to the cylinder, is moved endways by means of the hand lever to
which the stem of the valve is connected, as already explained.
The pistons are made to work steam-tight against the cylinder heads and the
central partition by being provided with steel rings let into annular grooves cut in
the sides of the piston, and pressed forward by means of springs placed behind
them:
The working points of the pistons are provided with a packing piece, which is
divided into two parts, and is received in a recess made in the piston, the two parts
being pressed outward against the ends of the cylinder by flat springs placed
between them. The oscillating steam stop or abutment is kept in contact with the

page_text: piston by the pressure of steam behind it, so that no spring is required to press the
steam stop down on the piston as in my former Patent.
In order to cut off the steam at different degrees of expansion I adapt to the
inside of the oscillating valve above-mentioned a second oscillating valve, which
works inside and independent of the first, and is mounted on a separate shaft or
stem, which passes longitudinally through the shaft of the first valve and is worked
by a separate excentric, and works a curved lever connected with the stem of the
second expansion valve.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Richard Hodson in the Great Seal Patent Office on the 23rd February
1878.
RICHARD HODSON, of Abbey Road, Saint John's Wood, in the County of
Middlesex, Civil Engineer. "IMPROVEMENTS IN ROTARY ENGINES AND IN THE
REVERSING GEAR TO BE ADAPTED THERETO, PARTS OF WHICH IMPROVEMENTS ARE
APPLICABLE TO OTHER ENGINES."
This Invention relates to various improvements upon an Invention of improve-
ments in rotary engines for which I obtained Letters Patent, dated Twenty-second
December, One thousand eight hundred and seventy-five, No. 4458.
The present Invention has for its main object to so construct and arrange the
parts of the engine that the piston rod, which forms the main driving shaft of the
engine, may be connected with the shaft to be actuated (for instance, the shaft of a
stern propeller) in such a manner that the latter may be driven in either direction
and quickly reversed without reversing or changing the direction of rotation of the
pistons in the working cylinders.
In the accompanying Drawing I have shewn various views of an arrangement of
parts whereby this object may be effected.
Fig. 1, Sheet I., is a longitudinal vertical section of a rotary engine with my
improved reversing gear and expansion gear adapted thereto; Fig. 2 is a plan view
of the same.
Fig. 3 is a rear or end elevation of the engine shewing the excentrics for working
the oscillating valves and feed pumps, as seen from about the dotted line A, B, on
the plan view Fig. 2.
.
- Fig. 4, Sheet II., is a transverse vertical section of the engine drawn upon an
enlarged scale, and taken in the line C, D, of Fig. 2, and shewing the piston at the
commencement of the stroke.
Fig. 5 is another transverse vertical section of the engine (also drawn on an
enlarged scale) taken in the same line, and shewing the piston at or near the end of
its stroke.
.
The piston shaft a is so mounted in its bearings that it is capable of being moved
longitudinally therein to a limited extent. The cam-shaped pistons b, b, (of which
there are by preference two, with their cam surfaces arranged opposite to each
other, and working in separate chambers formed by dividing the cylinder into two
equal parts by means of a central partition c), are not keyed fast on to their shaft,
but are simply mounted thereon, and are connected thereto by means of a feather
.

page_text: fixed in the shaft. This feather enters a groove formed in the central hole or boss
of the piston, so that the shaft with its feather is free to move longitudinally in the
piston or the piston on the shaft, but yet the shaft always revolves with the piston.
Both pistons 6, b', are mounted in the same way on the shaft a, and one end of the
piston shaft turns in a kind of cylindrical thrust block d, which is moveable, in a
cylindrical bearing either cast on the cylinder head or formed in a vertical standard d¹
placed in front thereof, and secured to the foundation plate of the engine, as shewn
at Fig. 1.
To the outer end-of this moveable thrust block d is connected a lever e, which is
mounted on a fulcrum pin on a bracket fixed to the vertical standard d'. The
upper end of this lever enters a slot in the end of the screw e*, which is carried by
the forked standard d¹ and operated by the hand wheel e² carrying the nut. By
turning this hand wheel the propellor shaft a can be moved longitudinally in either
direction. On to the other end of the piston shaft a is keyed a male friction clutch h
made in the form of a double cone. One side of this clutch takes into a conical
annular groove formed in a hollow cylinder or block mounted on the boss of the
bevil wheel j in such manner as to be capable of sliding longitudinally thereon, and
connected to the boss of the bevil wheel by a feather and groove, and also to the
web of the wheel by stud pins i, i. Between the inner face of the bevil wheel j.
and the hollow cylinder i is placed a spiral spring 1, by which the pressure of the
parts forming the friction clutch is made elastic in order that should any undue
resistance to the rotation of the propellor shaft suddenly occur, the parts forming the
clutch would not be in danger of breakage, but the springs 1, l, would be compressed
and the clutch allowed to slip.
The bevil wheel j is mounted loosely on the piston shaft o, and is free to revolve
thereon, together with the hollow cylindrical portion of the clutch i, in either
direction. The other side of the conical clutch h takes into a similar conical
annular groove made in a hollow cylindrical block k mounted on the end of the pro-
pellor shaft or other shaft a* which it is desired to actuate.
The hollow cylindrical block k is not keyed fast on the shaft a*, but is connected
thereto by a feather, which enters a groove formed in the boss of the hollow cylin-
drical block k, so that the latter, although obliged to rotate with the shaft a*, is
capable of an endway motion thereon, but is kept in contact with the clutch by a
spring placed behind it.
The cylindrical block / carries pins k¹ which enter holes in the web of the bevil
wheel m mounted on the shaft a*, and keyed fast thereto. Into both these bevil-
toothed wheels j and m gears an intermediate idle wheel n of the same kind, which
is mounted on a stud axle carried on the foundation plate of the engine.
It will now be evident that if the piston shaft a be pushed forward by means of
the lever e operated by the hand wheel e² so as to force the male clutch / into the
annular conical groove of the cylindrical block k, the shaft a* will be driven in one
direction, but if the piston shaft a be drawn back so as to bring the other side of
the clutch into gear with the hollow cylinder or block i attached to the bevil
pinion on the piston shaft a it will, through the bevil gear, impart motion to the
shaft a in the opposite direction, and if by bringing the lever e into a vertical
position the clutch h be placed midway between the two parts, no motion will be
communicated to the shaft a*.
As a modification of the above-described manner of sliding the engine shaft in
order to operate the clutch whereby a more instantaneous action of the gear may
be obtained, in place of the sliding thrust block I provide a piston at the end of
the engine shaft, working in a small cylinder furnished with the ordinary slide
valve for letting the steam in at either side of the piston. Suitable mechanism may
be attached to the slide valve, so that it may be operated from any convenient
place.
It will be obvious that on the admission of steam to either side of the piston the
engine shaft will be slidden in the direction required.
Instead of working the male clutch by moving the piston shaft end ways by means

page_text: of the lever e, as already explained, a lever may be adapted direct to the male clutch
so as to move the same in or out of gear without moving the piston shaft.
This arrangement will be particularly applicable to engines constructed according
to my former Patent, in which the pistons are keyed fast on to the piston shaft.
Although I prefer to use two working cylinders and pistons under ordinary cir-
cumstances, it will be obvious that three or more cylinders may be used in combination,
as would be required if the engine be intended to work at high and low pressure
by exhausting from one cylinder into another.
Fig. 6, Sheet I., is a side or end elevation; and Fig. 7 a longitudinal section of
one of the pistons b or b¹, drawn upon an enlarged scale, and shewing the method of
packing and oiling the same.
Figs. 8, Sheet II., arc side and sectional views of the abutment for the pistons,
drawn on an enlarged scale.
Figures. 9, 10, and 10ª, are enlarged views of the oscillating valves and steam
ports, shewn in plan and sections.
Figures 11, 12, 13, 14, 15, and 16, are diagram plan views of the main valve,
expansion valve, and ports of the cylinder in different positions with respect to each
other, according to the position of the piston in the working cylinders, and the
amount of cut off.
The valve gear of the engine consists of a main oscillating valve f, seen best in
cross section at Figures 4 and 5, and detached in plan and cross section at Figures 9,
and an oscillating expansion valve g, seen best at Figures 4 and 5, and detached in
plan and cross section at Fig. 10.
The main oscillating valve f is semi-cylindrical in cross section, and extends from
end to end of the steam chest. It is provided with a forked block, which embraces
the squared end of the sleeve shaft f. This sleeve shaft passes through a stuffing
box formed in the end of the valve chest, and carries a crank f2, to which is jointed
the rod of the excentric q on the engine shaft a. From this excentric the main valve
will receive a slight axial or oscillating motion so as to bring its openings or ports
into coincidence with the steam ports of the cylinder at the commencement of the
stroke of each of the pistons that those ports supply with steam, and close them only
when the axial motion of the pistons have brought them near their exhaust
passages.
The oscillating expansion valve g is also semi-cylindrical in cross section, but of
the same outer diameter as the internal diameter of the main valve.. This
expansion valve g is provided with a forked block g* which embraces the
squared end of a rock shaft g'. This rock shaft passes through the sleeve shaft f¹,
and carries a crank g² (see Fig. 2). To this crank is jointed the rod of an excentric g¹
on this engine shaft a. This valve g, like the main valve f, receives an axial oscil-
lation from the excentric g', thus bringing its inclined openings or ports into
coincidence with the openings or ports of the inain valve sooner
according to its longitudinally adjusted position. At the left-hand end of tlic valve,
as seen at Fig. 1, a segmental recess is formed to receive the flanged end of a
sliding rod g2 passing through a stuffing box formed on the end of the steam chest.
This sliding rod at its outer end is slotted to receive the lower end of a rock lever g³,
which has its fulcruin upon a bracket of the vertical standard d', and its upper end
moves between quadrant guides g*.
or later,
The steam is led into the engine by the passage 6x cast in the foundation plate of
the engine and up to the steam chest bs, by passages formed in the sides of the
cylinder. The exhaust is brought down through similar passages b* in the sides of
the cylinder to the hollow foundation plate of the engine from whence it is led to
the condenser through the pipes 65. This arrangement of the steam passage admits
of easy access to the interior parts of the engine, without disconnecting either steam
or exhaust pipes.
It will be seen on reference to the detached plan view of the steam chest b³
(Fig. 10) that the steam ports leading to each of the cylinders are cut through at
opposite angles with respect to the axis of the cylinder or engine shaft, and that thẹ.

page_text: main valve f, Fig. 9, and the expansion valve g, Fig. 10, are also pierced in a similar
manner as regards the angle of the opening, but the one opening has a lead of the
other, as shewn in the enlarged views of the valve, the expansion valve having in
addition a square opening g cut through it for the purpose to be presently explained.
When these two valves are superposed, as seen in Sheet II., on their semi-cylindrical
seat in the steam chest b³, the expansion valve g may be moved longitudinally by
means of the hand lever g³ and sliding rod 92 so as to cut off the steam from the
cylinders altogether, as shown at Fig. 15, or it may be slidden longitudinally into a
position to control the supply of steam to the cylinder, without altering the rate of
expansion dependent upon the main oscillating valve f, as shewn at Fig. 16; the
steam admitted in this case will be wire drawn, but it will be evident that by
exposing more or less of the main valve openings any desired amount of control
upon the steam to be admitted is obtained.
Fig. 11 shews a plan of the main valve f and the steam ports. In this
Figure the expansion valve g (shewn in dots), is so placed longitudinally as to
control the entrance of the steam, but not so as to cut off before the main valve;
the steam will not therefore in this case be acting expansively. This Figure
represents the valves in the position they would occupy when the piston is at the
commencement of its stroke, as seen at Fig. 4, which shews a section through the
piston 6' on the line 1, 1, of Fig. 11.
Fig. 12 shews the valves in their relative positions at the end of the stroke of the
piston 61, as shewn at Fig. 5.
Fig. 13 shews a plan of the main valve f, with the expansion valve g, shewn in
dots, so placed longitudinally with respect to the main valve f as to cut off the steam
at about half stroke. This Figure shews the parts in the position they respectively
occupy at the commencement of the stroke.
Fig. 14 is a similar plan view of the two valves, shewing the position of the
valves at the end of the stroke, corresponding to that shewn in the section,
Fig: 5.
It will now be understood that by the above-described longitudinal adjustment of
the expansion valve g, any degree of expansion of the steam in the cylinder can be
momentarily obtained while the engine is working, and that by this longitudinal
adjustment of the valve g the supply of steam may be regulated or the valve may
be used as a main stop valve for shutting off the steam altogether.
When it is desired to employ the engine in driving, pumping, hoisting, or other
mechanism, the clutch / is to be brought to an intermediate position by means of
the hand wheel e². Any desired amount of steam may then be admitted by shifting
the expansion valve g longitudinally through the hand lever g³; the power of the
engine can then be transmitted by band from the band pulley a¹.
The pistons b, b¹, are made to work steam-tight against the cylinder heads and
the central partition by being provided with steel rings let into annular grooves cut
in the sides of the piston and pressed forward by means of springs placed behind
them, as shewn at Figures 6 and 7. On the working faces of these rings are made
semicircular grooves or channels, which are supplied with oil in the manner shewn
in the Drawing. By this arrangement the oil is conveyed to the parts requiring
lubrication and confined there, such a quantity only of oil being allowed to escape
as can pass between metals in contact. By this means the useless expenditure of
the lubricating material is reduced to a minimum.
The working points of the pistons are provided with a packing piece b*, which is
divided into two parts, and is received in a recess made in the piston, the two parts
being pressed outwards against the ends of the cylinder by flat springs placed
between them. The oscillating steam stop or abutment o is kept in contact with
the piston by the pressure of steam behind it, so that no spring is required to press
the steam stop o down on the piston, as in my former Patent.
The ends of the abutment o are made steam-tight by forming them in two parts,
between which a central portion o¹ of the web, having shaped angles, is inserted,
by which means the pressure of the steam acting on this central portion o' forces

page_text: the two halves of the abutment outwards against the ends of the cylinder, as shewn
at Figures 8.
In adapting the improvements in valves of steam engines as above described to
engines having reciprocating pistons, I retain the form of expansion and main
valves, and operate them from two excentrics on the crank shaft of the engine by
suitable links or bell-crank or other rock levers. The valve chest may be arranged
either longitudinally or transversely of the cylinder.
Fig. 17 represents in cross section a portion of the cylinder and valve chest
arranged longitudinally of the cylinder, and Fig. 18 is a partial plan of the semi-
cylindrical seating of the valve chest.
The steam ports are set at opposite angles, as before described, but the exhaust
port 6 is in this instance made, as usual, rectangular. On the under side of the
main valve a recess 67 is formed of the shape shewn at Fig. 19, which is an under
side view of the valve detached. This recess 67, on the under side of the valve, is
so situated that the oscillating movement of the valve shall expose the recess 67 to
each steam port alternately. The position of the inclined openings or steam ports
of the main valve f give a fixed amount of expansion to the steam by cutting off the
supply before the piston has reached the end of its stroke, the exhaust recess 6' of
the main oscillating valve f opening to the other steam port of the cylinder before
the re-admission of the steam, as will be understood by inspecting the plan view,
Fig. 20, which shews the main valve at the middle of its oscillation in the direction
of the arrow.
The exhaust recess 67, shewn by dots in Fig. 20, uncovers the steam
port leading to one end of the cylinder 6° before the steam is admitted to the other
end of the cylinder by the inclined opening or steam port at the opposite end of the
main valve.
The construction, and the oscillating and longitudinal movements of the expansion
valve g, will be similar to that before described with respect to the rotary engine;
the inclined openings or ports being conformed to those of the main valve and steam
chest as respects distance apart and lead.
Having now described my Invention of "Improvements in Rotary Engines and
in the Reversing Gear to be Adapted thereto," and having explained the manner of
carrying the same into effect, I claim as the Invention secured to me by Letters
Patent as aforesaid,―
First. The general arrangement and construction of parts, herein shewn and
described, and constituting my improved rotary engine.
Second. I claim the construction and arrangement of reversing gear, herein set
forth, whereby the rotation of the shaft to be driven may be instantly reversed
without stopping or reversing the motion of the motive-power engine; or the engine
may be disconnected from the shaft and used for pumping or other purposes, as
above described.
Third. I claim the construction, arrangement, and mode of operating the valves,
as and for the purposes herein set forth.
In witness whereof, I, the said Richard Hodson, have hereunto set my hand
and seal, the Twenty-third day of February, in the year of our Lord One
thousand eight hundred and seventy-eight.
RICHARD HUDSON. (L.S.)