Improvements in Steering Gear.
Year: 1893

page_text: Improvements in Steering Gear.
1, JOHN SCOTT, of Bute House, Cannhall Road, Leytonstone, in the County of
Essex, Engineer, do hereby declare the nature of this invention and in what
nanner the same is to be performed, to be particularly described and ascertained
n and by the following statement :--
My invention relates to steering gear of the kind in which an engine is used for
operating the rudder and consists essentially in the novel arrangement of mechanism
for controlling the valves of such engines.
:
In carrying out my invention I provide the crank-shaft of the engine with an
extension eccentric to the other portion thereof, and upon this eccentric extension
I mount a sleeve to which the steering wheel is secured and having upon it the
eccentric for driving the valves. The eccentricity of the eccentric relatively with
the axis of the sleeve is the same as the eccentricity of the extension of the crank-
shaft relatively with the crank-shaft, whereby the eccentric for operating the valves
may be placed so that its eccentricity compensates for that of the extension or
in other words so that its periphery is concentric with the crank-shaft.
The motion of the engine is preferably transmitted to the steering chain through
the medium of a pinion upon the crank-shaft engaging with the interior of a wheel
mounted upon a shaft to which the grooved drum or barrel, around which the
steering chain is passed one or more times is secured.
To enable my invention to be fully understood I will describe the same by
reference to the accompanying drawings, in which :-
Figure 1 is a sectional elevation of a steering-gear having my improvements
applied thereto, the steering wheel and one of the side frames being removed in
order that they shall not obstruct the parts behind them; and,
Figure 2 is a vertical section of the same, the cylinders and other parts of the
engine being removed for the sake of clearness :
Figure 3 is a view illustrating a slight modification of my invention:
Figures 4, 5 and 6 are sectional diagrammatic views illustrating the operation of
my apparatus.
b
a, a are two side frames or brackets which with the base-plate upon which they
are mounted form the framing of the engine. c, c' are the engine cylinders
suitably mounted upon the said framing at right angles to each other, and d is the
engine crank-shaft which is mounted in bearings in the upper part of the framing.
e is the pinion mounted upon the end of the crank-shaft, and is the wheel with
the interior of which the said pinion engages and which is mounted upon a shaft g
carrying the drum or barrel over which the steering chain which is indicated by
the dotted lines is passed in a well known manner. j, j are guide-rollers under
which the said chain is passed.
As shewn in Figure 2, the wheels e and are represented as engaging with each
other by frictional contact: as, however, objection might be raised to this arrange-
ment on the ground that under certain circumstances there would be a certain
amount of slip between the two wheels, it is to be understood that ordinary
gearing with teeth may be employed. When, however, teeth are employed there
is a liability of back-lash owing to the action of the water upon the rudder. I
overcome both of these objections, namely that of slipping and that of back-lash,
by employing combination gearing of the kind shewn in Figure 3, that is to say,
With this arrangement it
gearing which is partly toothed and partly frictional.
is obvious that the teeth will prevent the slipping of the frictional gearing and the
frictional gearing will prevent back-lash.

page_text: Where I employ frictional gearing either wholly or partly I prefer that the
pinion e should support the whole weight of the wheel, and for this purpose I
arrange the bearing g' of the shaft g to slide in vertical guides, as shewn in
Figures 1 and 2, the said bearing giving lateral support to the said shaft g without
vertical support.
k is the eccentric extension of the crank-shaft d, and 7 is the sleeve mounted
upon the said extension and having fixed to it the steering wheel m.
n is the
eccentric by means of which the valves of the engine are moved, the said eccentric,
as shewn in Figure 2, being formed in one piece with the sleeve l and made broad
enough for carrying two eccentric straps, namely, one for operating the slide-valve
of each engine.
The operation of the mechanism for controlling the valves is as follows:-
Assume the sleeve to be in such a position upon the eccentric extension k of the
crank-shaft that the eccentricity of the eccentric n compensates or neutralises
the eccentricity of the extension, that is to say, so that the periphery of the said
eccentric is concentric with the crank-shaft d. In this position of the said
eccentric the slide-valves o, o' are in their central positions and cover the ports of
the cylinders c, el respectively, as shewn in Figure 4, so that no steam can enter
the same.
Also in this position of the slide-valves the piston p of one engine
should be at about the centre of its stroke, the piston pl of the cylinder c¹ being at
one end of its stroke also as shewn in Figure 4. Assume now that it is desired to
move the rudder to "starboard," for which purpose the steering-wheel, which is
indicated by the dotted lines in Figure 1, is moved in the direction of the arrow 1
in the said figure and in Figures 4 and 5; the result of this movement is that the
eccentric n is also moved in the same direction, slightly in advance of the crank
whereby the valve o of the cylinder c is moved to admit steam to the upper side of
the piston p and the valve o¹ of the cylinder c¹ to admit steam to the under side of
the piston p', the effect of which is that the crank-shaft is rotated also in the
direction of the arrows 1. As long as the eccentric n is kept slightly in advance
of the crank by turning the steering-wheel the engine will continue to rotate: as
soon, however, as the steering wheel is stopped the crank-shaft will only continue
to move until the eccentricity of the extension k thereof neutralizes or partly
neutralizes that of the eccentric n so as to cause the slide-valves to again cover the
ports and shut off the steam to their respective cylinders.
If it is desired to move the rudder to "port" the wheel m is moved in the
direction of the arrows 2, Figures 1 and 6, so that the valve o is moved to admit
steam to the lower side of the piston p of the cylinder c whilst the valve o' is
moved to admit steam to the lower side of the piston p' of the cylinder c', as shewn
in Figure 6, whereby a rotation also in the direction of the arrow 2 is imparted to
the crank-shaft, which rotation ceases when the crank-shaft has rotated far enough
to cause the eccentric eccentricity of the extension k of the said shaft to neutralize
or partly neutralize that of the eccentric n and thus cause the slide-valves to again
cover the ports.
As in heavy seas the strain upon the rudder might cause the movement of the
engine, I preferably provide on the periphery of the wheel f friction-brake
connected to a lever extending to a position in which it can be depressed by the
steersman to apply the brake during such time as no movement is to be imparted
to the rudder.
Should the steam driving-mechanism break down I provide for locking the
wheel in with its sleeve to the extension of the crank-shaft by means of a nut s,
in which case the movement of the wheel is directly communicated through the
crank-shaft and the gear-wheels to the chain-barrel.
g
To indicate the position of the rudder to the helmsman I provide the shaft
carrying the drum h with an extension t having a worm formed upon it and
engaging with a worm-wheel u to which is fixed a shaft having at its upper end a
pointer w moving over a dial ¿

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a ship's steering-gear driven by an engine, providing the crank-shaft of the
said engine with an extension eccentric to the crank-shaft and mounting upon the said
eccentric extension a sleeve having an eccentric, the eccentricity of which relatively
with the sleeve is the same or substantially the same as the eccentricity of the
extension relatively with the shaft, whereby when the eccentric is in such a position
upon the extension that its eccentricity compensates or neutralizes that of the said
extension the ports of both the engine cylinders are covered by the slide-valves,
substantially as described.
2. In a steering gear. of the kind herein before described locking the steering-
wheel to the extension of the crank-shaft in such a manner that the said steering
gear can be moved by hand, substantially as described.
3. The manufacture and use of the improved ship's steering-gear hereinbefore
described and illustrated in the accompanying drawings and operating as set
forth.
ונים
1
.1
1000
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.