IMPROVEMENTS IN STEAM STEERING GEAR
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by the said Charles Ross Simey at the
Office of the Commissioners of Patents on the 13th July 1880.
CHARLES ROSS SIMEY, of Sunderland, in the County of Durham. “IMPROVEMENTS
IN STEAM STEERING GEAR."
My improvements in direct acting steam steering gear have for their objects to
reduce the space occupied by the apparatus, lessen the consumption of steam, and
avoid oversteering or putting the helm farther over than is required to bring the
ship back to her course when she deviates only slightly from it.
The Invention relates, 1st, to the construction and arrangement of the apparatus,
and particularly to the employment of a rack and pinion, or their equivalent,
arranged alongside the piston rod for converting the reciprocating rectilinear motion
of the steam piston into alternate rotary motion for operating the tiller chains
and actuating the valve gear, or for the latter purpose only in some cases; 2nd, to
a method of working the steam piston within certain limits from its mid position
by the difference in pressure between live steam on one side of the piston and
partially condensed steam on the other side of the piston (where' it has been
confined more or less since the piston was previously moved by it in the opposite
direction) whereby the consumption of steam in working the apparatus within the
limits necessary to keep the vessel on her course at sea is reduced to a minimum,
and oversteering prevented; and 3rdly, to the combination with a direct acting
steering gear of the self acting valve gear described in a former Patent granted to
me, dated April 22nd, 1879, No. 1586.
The steering gear comprises a single fixed horizontal steam cylinder to a cross-
head, on whose piston rod is attached a rack, the said rack being parallel with the
piston rod and working in suitable guides alongside of the cylinder. The rack
gears with a pinion which it rotates once during the full stroke of the piston, the
pinion being on a shaft on which is also fixed a drum, to which the tiller chains
are attached, the drum being so proportioned as hy one revolution to shift the
helm from hard over on one side to hard over on the other side. This shaft is also
geared with and operates the tubular spindle forming part of the valve gear
described in my former Patent, and therein referred to as operating the lever
crosshead (by which the position of the valve is governed) in the same direction
to that in which it is moved by hand, the arrangement and operation of the
concentric spindles, their lever arms, links, and lever crosshead, in connection with
the valve, being similar to that described in my former Patcut.

page_text: The slide valve in the present case is an ordinary D valve with only sufficient
lap on the steam side to close both ports steam-tight when at the middle of its
travel, but on the exhaust side the lap is so groat as to allow of the induction port
at the one end being considerably opened before the eduction port at the other end
is opened, so that the pressure of the live steam will, unless the valvo be moved far
enough to open the eduction port, be opposed and partially balanced by the steam
on the other side of the piston. Now the piston is at the middlo of the cylinder
when the helm is at "steady," and as when a ship is at sea it is only necessary
(except on emergency) to move the helm a few degrees to starboard or port to keep
her on her course, for which but little power is required, as the resistance of the
water to the rudder is small, a great waste of steam would be incurred by emptying
one end of the cylinder of steam cach time the helin is moved a little way, and
there is great liability of oversteering, but by giving considerable lap on the exhaust
side neither end of the cylinder is emptied of steam except it be intended to put
the helm hard over. Both ends of the cylinder therefore generally remain full of
steam, which is subject to loss of pressure only by condensation, and (if necessary)
by escaping slowly through a small relief port or holo provided in the lap of the
valve. Therefore but little fresh steam is required to be admitted to the one end
of the cylinder, and its pressure being greater than that of the steam confined at
the other end of the cylinder, and which has lost pressure by condensation and by
slow escape, as above mentioned, the piston will be moved by the excess of pressure
of the live steam through the small distance required to shift the helm far enough
to keep the vessel to her correct course. If, on the other hand, it is required to put
the helm hard over, or nearly so (which occurs but occasionally), then the valve is
moved sufficiently to fully open both the induction and eduction ports, thus
allowing the full pressure of steam from the boiler to act on the piston unopposed
at the very time that the greatest power is required to move the helin. The
exhaust edge of the valve may be notched to prevent the too sudden opening of
the eduction port, and in order to carry off the condensed water from the cylinder
I can carry the steam port inlet quite to the bottom of the cylinder, so that when
the exhaust port opens the outgoing steam carries all the water with it. The travel
of the valve is so proportioned to the stroke of the piston that if the handle or
tiller (by means of which the valve is moved by hand) be shifted from "steady,"
say, to half way to "hard a port" or "starboard," the travel of the piston will be
half way from the middle to one end of the cylinder, when the valve will, by the
action of the valve gearing, be returned to its former position, so as to close both
ports and so prevent further admission or egress of steam. The action of the valve
gear is also such that if, when the helm is held at starboard or port by the steam-
pressure on the piston, this pressure should decrease and allow the piston and helm
to fall back, then the valve will be proportionately moved to admit enough more
steam to bring the piston and helm up again to their former position, which
corresponds to that in which the steering handle or tiller is placed by the steersman.
Also should a tiller chain break when the helm is nearly hard over the action of
the valve gear will cause steam to be admitted to the opposite end of the cylinder,
thereby proventing damage by the piston striking the end of the cylinder.
For steering by hand a steering wheel operates the chain drum shaft through
worm gearing, and can be thrown in and out of gear by a clutch that may also
throw the rack and pinion above described for working by steam in and out of
gear at the same time if desired.
By a modified arrangement I may dispense with the chain drum and use the
rack and pinion only for actuating the valve gear when steering by steam, and
for moving the piston when steering by hand. In this arrangement the tiller
chains have their ends made fast to fixed points, and are passed round pulleys
on the piston rod crosshead, which thus moves to and fro in the bights of the
chains.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Ross Simey in the Great Seal Patent Office on the 13th
January 1881.
CILARLES ROSS SIMEY, of Sunderland, in tho County of Durham. "IMPROVEMENTS
IN STEAM STEERING GEAR."
My improvements in direct acting steam steering gear have for their objects to
reduce the space occupied by the apparatus, lessen the consumption of steam, and
avoid over-steering, i.c., putting the helm farther over than is required to bring the
ship back to her course when she deviates only slightly from it.
The Invention relates, 1st, to the construction and arrangement of the apparatus,
and particularly to the employment of a rack and pinion, or their equivalent, for
converting the reciprocating rectilinear motion of the steam piston into alternato
rotary motion for operating the tiller chains and actuating the valvo gear (or for
the latter purpose only in some cases), the said rack or its equivalent being parallel
to the piston rod and cylinder, and not in the same axial line therewith; 2nd, to
a method of working the steam piston within certain limits either way from its mid
position, by admitting steam to one end of the cylinder without exhausting from
the other end, so that the movement of the piston is caused merely by the
temporary difference in pressure between live steam at one side of the piston, and
the partially condensed steam which has cooled down by being confined at the
other side of the piston since the piston was previously moved by it in the opposite
direction, whereby the consumption of steam is reduced to a minimum in working
the apparatus within the limits corresponding to the small angular movement of
the helm necessary to keep the vessel on her course at sea, and over-steering is
prevented by the cushioning of the piston by the confined steam; 3rd, to a means
of removing the condensed water from the cylinder each time the steam is
exhausted; and 4thly, to the combination with a direct acting steam steering
gear of the self acting valve gear described in a former Patent granted to me,
dated April 22nd, 1879, No. 1586.
In order that the Invention may be more readily understood, I havo illustrated
it in the accompanying, Drawings and will proceed to describe it with reference
thereto. Figure 1 is a plan, Figure 2 a front elevation, and Figure 3 a side
elevation of my improved steering gear. Figures 4, 5, 6, are sections of the slide
valve in different positions.
A is a horizontal steam cylinder fixed by perference athwartships upon a suitable
sole, and B is its piston rod. C is a crosshead fixed on the piston rod B. The rear
end of said crosshead is fitted to slide in or on a dovetailed or other guide frame c,
so as to prevent any lateral strain or deflection of the piston rod by the strain of
the rack gear next described. Or instead of this guide frame, two piston rods
might be used, placed side by side and passing through separate stuffing hoxes, to
obtain greater rigidity than with a single central piston rod. D is a rack rigidly
connected by one end to the front end of this crosshead C, the said rack being
parallel to the piston rod B and fitted to slide in a grooved way d on the cylinder
A alongside of which it extends, as shown. By this arrangement of the rack tho
apparatus occupies much less space athwartships than it otherwise would. This rack.
D gears with a pinion E keyed on the upright shaft F, upon the lower end of which
the tiller chain drum G is also keyed; H, H', is the tiller chain, and g,g, are guide
sheaves, one at either end of drum C, by which the bight of the chain is held in
gear with the drum G, around one half of which it passes. The portions H, H', of
the chain pass around guide sheaves and are connected to the tiller in the usual
way. It will be obvious that the shaft F might be horizontal instead of vertical, in
which case the rack D would be on top of the cylinder. The pinion E and chain

page_text: -
drum G are by preference so proportioned to the stroke of the piston that the
pinion is rotated once by the movement of the piston from one end of the cylinder
to the other, and one revolution of the drum G is sufficient to move the helm from
hard over to port to hard over to starboard, or vice versa; I is a pinion keyed on
the upper part of shaft F and gearing with a toothed quadrant K koyed on the
tubular spindle L, forming part of the valve gear described in my said former
Patent; M is the inner spindle of the said valve gear passing through L and having
a handle M' fixed on it, an index L¹ being fixed on the tubular spindle L, and
working over a fixed quadrant graduated to correspond with 8 points of the
compass, 4 to starboard and 4 to port. l, m, are short lever arms respectively
fixed to the lower ends of the spindles L, M. They are diametrically opposite one
another and are respectively connected by links n, n with the two ends of a lever
N, to the middle of which is jointed the valve rod v. The arrangement and
operation of the valve gear being precisely the same as described in my said former
Patent, no further description is necessary.
The slide valve in the present case is an ordinary D valve, and is represented
separately in section in 3 different positions, in Figures 4, 5, and 6. The
valve V has only sufficient lap on the steam side to close the ports to both ends
of the cylinder steam tight when at the middle of its travel, as shown in Figure 4,
but on the exhaust side the lap is so great as to allow of the valve being moved
sufficiently to open the port to one end to the steam, before the port to the other
end is opened to the exhaust, as shown in Figure 5, so that the pressure of the live
steam will be opposed and partially balanced by the steam confined at the other
side of the piston. By moving the valve still farther however, both ports may be
full opened to the steam and to the exhaust q respectively, as shown in Figure 6.
Now the piston is at the middle of the cylinder A when the helm is at " steady,"
and as, when a ship is at sea, it is only necessary (except on emergency) to move
the helm a few degrees from starboard or port to keep her on her course, for which
but little power is required, a great waste of steam is incurred by exhausting from
one end of the cylinder each time the helm is moved a little way, and there is great
liability of over-steering; but by giving the valve considerable lap on the exhaust
side, the steam is not released to the exhaust, except it be intended to put the
helm hard over. Both ends of the cylinder therefore generally remain full of steam,
which is subject to loss of pressure only by condensation and (if necessary) by
escaping slowly through a small relief port or hole provided in the lap of the valve.
Therefore but little fresh steam is required to be admitted to the one end of the
cylinder, and its pressure being greater than that of the steam confined at the
other end of the cylinder, and which has lost pressure by condensation (and perhaps
by slow escape, as above mentioned) the piston will be moved by the excess of
pressure of the live steam through the small distance required to shift the helm far
enough to keep the vessel to her correct course. If on the other hand it is required
to put the helm hard over, or nearly so, which occurs but occasionally) then the
valve is moved sufficiently to fully open the two ports to the steam and exhaust
respectively, thus allowing the full pressure of steam from the boiler to act on the
piston unopposed, at the very time that the greatest power is required to move the
helm. The exhaust edge of the valve may be notched to prevent the too sudden
opening to the exhaust.
"
"
The travel of the valve is so proportioned to the stroke of the piston that if the
handle or tiller M' be shifted from "steady," say two points to port or
"starboard," the valve will be correspondingly moved from the closed position
(Figure 4) and the piston will be caused to travel halfway from the middlo to one
end of the cylinder, whereupon the valve will, by the action of the valve gearing,
be returned to its former position (Figure 4) so as to close both ports and prevent
further admission or egress of steam. The action of the valve gear is also such
that if, when the helm is held at starboard or port by the steam pressure on the
piston, the pressure should decrease and allow the piston and helm to fall back,
then the valve will be proportionately moved to admit enough more steam to bring

page_text: the piston and helm up again to their former position, which corresponds to that in
which the steering handle or tiller ML is placed by the steersman. Also should a
tiller chain break when the helm is nearly hard over, the action of the valve gear
will cause steam to be admitted to the opposite end of the cylinder, thereby
proventing damage by the piston striking the cylinder cover.
In order to carry off the condensed water from tho cylinder, I continue the ports
o, p, through the cylinder covers on the end of the cylinder itself, as shown in
section in Figure 2, and quite down to the underside of tho cylinder, so that
immediately the exhaust port opens, the outgoing steam carries with it all the
water that may have collected in that end of the cylinder.
For steering by hand a steering wheel S operates the chain drum_shaft_F
through worm & on the hand wheel shaft 8', gearing with a worm wheel T on the
chain drum shaft. This shaft is mounted in arms u fixed on a shaft U, which is
rocked by a hand lever U¹, to move the shaft a' sideways and throw worm 8 out of
gear with wheel T when steam power is employed.
Having described my said Invention and the manner of porforming the same,
I declare that what I claim as my Invention to be protected by the hereinbefore
in part recited Letters Patont is,-
1st. The improved direct acting steam steering genr constructed and operating
substantially as herein shown and described.
•
2nd. In a direct acting steam steering gear in which the helm is moved from
port to starboard by a single stroke of the piston, the employment of a rack or
its equivalent connected to the piston rod, and arranged to work parallel theroto
and along the outside of the cylinder, and gearing with a pinion on the chain drum
shaft, for converting the reciprocating rectilinear motion of the piston into
alternate rotary motion of the chain drum shaft, substantially as shown and
described.
3rd. In a direct acting steam steering gear in which the helm is moved from
port to starboard by a single stroke of the piston, the method of working the
steam piston by admitting live steam to one end of the cylinder without releasing
the steam from the other end, so that the live steam at one side is opposed by the
partially condensed steam confined at the other side, substantially as and for the
purpose specified.
4th. In a direct acting steam steering gear, the employment of a slido valve
baving sufficient lap on the exhaust side to allow of steam being admitted to one
end of the cylinder without the steam being released from the other end of the
cylinder, substantially as shown and described.
5th. The combination with a direct acting steam steering gear, of the self acting
valve gear arranged to operate substantially as shown and described.
6th. In a horizontal steam cylinder, the arranging the ports to lead into the
cylinder at the lowest side in order that all water of condensation may be carried
out by the exhaust steam, substantially as shown and described.
In witness whereof, I, the said Charles Ross Simey, have hereunto set my
hand and scal, this Twelfth day of January, A.D. 1881.