IMPROVEMENTS IN APPARATUS FOR STEERING SHIPS
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by Andrew Betts Brown and William
Falconer King at the Office of the Commissioners of Patents on the 16th May
1881.
ANDREW BETTS BROWN, Engineer, and WILLIAM FALCONER KING, Electrician,
both of Edinburgh, in the County of Mid Lothian, North Britain. "IMPROVEMENTS
IN APPARATUS FOR STEERING SHIPS."
This Invention has for its object, by a combination of electrical appliances with a
magnetic compass and with hydraulic or steam steering apparatus, to provide for
automatically maintaining a ship in a required course by suitably acting on the
rudder when deviations from the course occur.
When a ship fitted with the improved apparatus deviates from the predetermined
course, the deviation causes one or other of two electric contact pieces to make
contact with a third piece carried by the compass, and in consequence of the
contact an electromotor is set in motion, such electromoter being actuated by means
of an electric battery or other generator of electricity, an electric relay being used
if necessary. The electromoter moves the valve or valves of the hydraulic or
steam apparatus which moves the ship's rudder, and the movement of the
apparatus causes the valve or valves to be restored to the neutral position. For
the purpose of preventing the rudder from being put too far or hard over to either
side when the deviation is small, the electrical contact pieces are arranged to be
shifted to a certain extent in a manner corresponding to the movement of the
rudder, so that when the rudder moves a little way to either side the contact
which brought about the movement becomes broken and the movement arrested.
The details of the apparatus may be variously modified, but a modification
which is at present preferred by the applicants comprises the following arrange-
ments-The compass consists of two or more magnetic needles, of a length of four
or five inches, fixed parallel to each other and arranged so that their vibratory
period may be such as to give sufficient steadiness at sea. To the compass there is
attached a contact piece of thin platinum wire which projects horizontally and is
in electric contact with the compass bowl. This compass contact piece extends
between two platinum contact pieces which are carried by but insulated from the
bowl, and which can be adjusted more or less apart. The compass contact piece is
connected to one pole of an electro-magnetic relay, and the other two contact
pieces are connected respectively to the zinc and copper poles of a galvanic battery,

page_text: whilst the centre of the battery is connected to the other pole of the relay. The
compass bowl fitted with gimbals in the usual way is attached to a vertical shaft
with provision for adjusting it on the shaft to suit the course it is intended the
ship shall take; and the shaft has on it a lever which is connected to the rudder
for the purpose herein before referred to of shifting the bowl so as to break the
contact whenever the rudder has moved to a position for correcting a deviation.
The electro-magnetic relay is arranged to make contacts as required in circuits
arranged between a sufficiently powerful galvanic battery and an electromoter
arranged to impart rotation to a shaft, which through speed-reducing gearing gives
motion to a shaft formed with right-hand and left-hand screw threads. This
screwed shaft shifts the valve of hydraulic apparatus, which acts on the rudder by
preference through the intervention of more powerful apparatus; and there is also
a suitable connection between the screwed shaft and the lever, or equivalent part
controlling the valve or valves of the main rudder moving apparatus, whereby the
valve of the intermediate apparatus is restored to its neutral position whenever
the movement of the part it acts on becomes effected.
It is in practice necessary to prevent oscillations from taking place without
proper cause between the compass contact piece and the two other contact pieces;
and for this purpose the compass is connected to the bowl by an insulated wire,
arranged not only for forming the electric connection to the compass contact piece,
but also to act as a spring to restrain comparatively violent movements, or separate
springs may be applied for the latter purpose. The two outer contact pieces are
mounted on a block having some weight, and which is pivoted on a centre below
the compass pivot. This block is connected by insulated wires (one for each
contact piece) to the bowl, these wires being arranged to act as springs, or separate
springs being applied; and on the block there are set two small boxes containing
oil or other suitable liquid into which there dips blades carried by arms fixed to
the compass.
With these arrangements the compass and the block carrying the
two contact pieces are rendered comparatively steady in their relative movements,
and the apparatus consequently acts in a more satisfactory manner.
When steam steering apparatus is employed a small hydraulic regulating
cylinder is introduced into the combination, to prevent too rapid movements being
caused by the valve acted on by the electromotor. The piston of the steam
cylinder constituting the intermediate apparatus, and which acts on the valve or
valves of the main steam apparatus, is connected by a rod to the piston of the
hydraulic cylinder. Water or other liquid is confined in the hydraulic cylinder,
but can pass from one end to the other through passages and a valve connected to
the valve of the steam cylinder. The water can pass only at a rate depending on
the size of the passages, and when the valve is shut it cannot pass, but locks the
piston in whatever position it has at the moment, whilst the steam piston being
connected to the hydraulic piston cannot move excepting as controlled by the
hydraulic piston.