IMPROVE- MENTS IN STEAM STEERING ENGINES
Year: 1881

page_text: LETTERS PATENT to Hugh Muir and James Caldwell, both of Glasgow, in the
County of Lanark, North Britain, Engineers, for an Invention of "IMPROVE-
MENTS IN STEAM STEERING ENGINES."
PROVISIONAL SPECIFICATION left by the said Hugh Muir and James
Caldwell at the Office of the Commissioners of Patents on the 14th September
1881.
HUGH MUIR and JAMES CALDWELL, both of Glasgow, in the County of Lanark,
North Britain, Engineers. "IMPROVEMENTS IN STEAM STEERING ENGINES."
This Invention has for its objects to simplify and otherwise improve the
construction of steam steering engines, to economise space, to increase their
efficiency, and to render them more accessible in all their parts.
In the improved engines a pair of inverted vertical cylinders act on overhung
crank pins at right angles to each other on the ends of a horizontal shaft, having
at its middle a screw worm which is by preference turned out of a solid wrought"
iron forging, and is enclosed in a casing provided with an oil box. The worm
drives a worm wheel on a short shaft which is geared by bevil or spur wheels to a
third shaft, having fast on it either a chain pulley or barrel from which a chain
transmits the action to the rudder. The steam cylinders are provided with
ordinary slide valves worked by eccentrics on the worm shaft, and the action
of the engines is controlled by a third valve constructed like an ordinary slide
valve and working upon a port face having ports communicating with the cylinder
valve casing or casings and exhaust passages, and also having a port communicating
with the exhaust pipe, the steam being admitted to the casing in which the third
valve works and the pressure keeping the valve tightly on its port face. The
engines work in one direction or the other, accordingly as the third slide valve is
moved to uncover one or other of its ports; and the movement of this valve is
transmitted from a hand steering wheel through differential gearing so connected
with the main gearing that any action of the engines consequent on a movement of
the third slide valve returns that valve to its neutral position, an action the object
of which is well understood.

page_text: In one modification of the gearing connected with the third slide valve the
handwheel shaft turns a central pinion which gears with a loose pinion on a crank,
and this loose pinion gears with an internally toothed wheel concentric with the
central pinion. The crank carrying the loose pinion is on a tubular shaft through
which the handwheel shaft passes, and which has on it a crank, eccentric, or lever
acting on the rod of the third slide valve. When the handwheel shaft is turned
the central pinion makes the loose pinion roll round the internally toothed wheel,
and this pinion carrying round the crank causes the third slide valve to move so
as to start the engines in the required direction. The internally toothed wheel is
connected to the gearing of the main engines, and when these engines move and
turn that wheel it makes the loose pinion roll round the central pinion in a manner
to carry the crank back to its middle position and thereby return the third slide
valve to its neutral position. Three bevil wheels may be substituted for the
central pinion, loose pinion, and internally toothed wheel, the middle bevil wheel
being carried on an arm which transmits the movements to the third slide valve,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Hugh Muir and James Caldwell in the Great Seal Patent Office
on the 13th March 1882.
HUGH MUIR and JAMES CALDWELL, both of Glasgow, in the County of Lanark,
North Britain, Engineers.
"IMPROVEMENTS IN STEAM STEERING ENGINES."
"
Our said Invention has for its objects to simplify and otherwise improve the
construction of steam steering engines, to economise space, to increase their
efficiency, and to render them more accessible in all their parts.
In our improved engines a pair of inverted vertical cylinders act on a horizontal
crank shaft from which motion is transmitted through worm wheel and other
gearing hereinafter more particularly described to a chain pulley or barrel from
which a chain transmits the action to the rudder. The steam cylinders are
provided with ordinary slide valves and the action of the engines is controlled by a
third valve constructed and acting like an ordinary slide valve and moved from a
hand steering wheel through differential gearing so connected with the main
gearing that any action of the engines consequent on a movement of the third
slide valve returns that valve to its neutral position, an action the object of which
is well understood.
And in order that our said Invention and the manner of performing the same
may be properly understood we hereunto append a Sheet of explanatory Drawings,
to be hereinafter referred to and representing a modification of our improved
steering engines.
Figure 1 on the accompanying Sheet of Drawings is a vertical longitudinal
section of our improved steering engines; Figure 2 is a plan; Figure 3 is a side
elevation, and Figure 4 is a front elevation. In these Drawings the same reference
numerals are used to mark the same or like parts wherever they are repeated.
In these steering engines a pair of inverted vertical cylinders 5 are bolted to the
upper front parts of side standard 6, forming part of the framing, and are arranged.
to act through connecting rods 7 on overhung crank pins at right angles to each
other on discs 8 on the ends of a horizontal shaft 9, having at its middle a screw-
worm 10, which is by preference turned out of a solid wrought iron forging, and is
enclosed in a casing 11 provided with an oil box 12. The worm 10 drives a
worm wheel 13 on a short intermediate shaft 14, which is geared by bevil wheels 15
to a third shaft 16 having fast on it a chain pulley 17, from which a chain guided
by pulleys 18 transmits the action to the rudder. The intermediate shaft 14 may
be placed horizontally, and be geared to the third shaft 16 with spur gearing, and
a barrel may be substituted for the chain pulley 17.
The steam cylinders 5 are provided with ordinary slide valves worked by
eccentrics 19 on the worm shaft 9, but these valves are fitted and guided so as not
to lift from their port faces when the steam pressure acts in what are ordinarily
the exhaust ports. The third or controlling valve 20, which is shown in section
in Figure 1, works on a port face having two passages with an exhaust port
between them, the steam being admitted into the casing 21, in which the valve 20
works, and passing off through the said exhaust port. The passages communicate
one with the valve casings of the cylinders 5, and the other with what would
ordinarily be the exhaust ports of those cylinders; and when one passage is
uncovered by the valve 20, the steam acts in the ordinary way in the valve
casings of the cylinders 5, but when the other passage is uncovered the steam acts
in the reverse way. The engines consequently work in one direction or the other,
accordingly as the third slide valve 20 is moved to uncover one or other of the
passages. The movement of this valve 20 is transmitted from a hand steering

page_text: wheel 22 fitted in immediate connection with the engines, or from a more distant
hand steering wheel 23 fitted upon a pedestal 24 on an upper deck or bridge.
Both of the hand steering wheels 22, 23, are geared by bevil wheels to a vertical
shaft 25, which is hereinafter termed the handwheel shaft.
In the modification of differential gearing fitted to the engines, shown in the
Drawings, the handwheel shaft 25 turns a central pinion, which is concentric with
and concealed by an internally toothed wheel 20 fast on a short shaft geared by
bevil wheels 27 to the pulley shaft or barrel shaft 16 of the main gearing. There
is an annular space between the teeth of the internally toothed wheel 26 and the
pinion on the lower end of the hand wheel shaft 25, and in this space there is a
planet pinion gearing with the central pinion and with the internally toothed
wheel. The planet pinion is loose on a crank pin fixed to an arm 28 on a tubular
boss or short shaft 29 (through which the handwheel shaft 25 passes), and this.
boss 29, extending up through a bearing 30, has on its upper end an eccentric or
cam working within a strap or frame 31 which works the controlling or third
valve 20. When the handwheel shaft 25 is turned the central pinion makes the
loose planet pinion roll round the internally toothed wheel 26, and this pinion
carrying round the crank arm 28 causes the third slide valve 20 to move so as to
start the engines in the required direction. When the main engines move a
corresponding movement is imparted through the bevil wheels 27 to the internally
toothed wheel 26, which makes the loose planet pinion roll round the central
pinion in a manner to carry the crank arm 28 back to its middle position, and
thereby return the third slide valve 20 to its neutral position. Three bevil wheels
may be substituted for the central pinion, loose planet pinion, and internally
toothed wheel, the middle bevil wheel being carried on an arm which transmits
the movements to the third slide valve 20.
Having thus particularly described our said Invention, and the manner of per-
forming the same, we have to state that we do not restrict ourselves to the precise
details herein described or delineated, but that what we believe to be novel and
original, and claim as the Invention secured to us by and in terms of the herein-
before in part recited Letters Patent is,-
1. The arranging or combining together of the parts of steering engines,
substantially in the improved manner herein described and shown in the
accompanying Drawings.
2. The combination of toothed differential gearing with valve details of steering
engines, substantially such as are hereinbefore described.
3. The enclosing of the worm on the crank shaft in a casing and providing the
same with a lubricator, as hereinbefore described.
In witness whereof, we, the said Hugh Muir and James Caldwell, have
hereunto set our hands and seals, this Tenth day of March, in the year of
our Lord One thousand eight hundred and eighty-two.
HUGH MUIK.
(L.S.)
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
JAMES CALDWELL. (L.S.)