Improved Means for Ascertaining and Correcting the Heeling-error in Ships' Compasses.
Year: 1889

page_text: リ
Date of Application, 31st Jan., 1889-Accepted, 22nd June, 1889
COMPLETE SPECIFICATION.
Improved Means for Ascertaining and Correcting the Heeling-error
in Ships' Compasses.
I, JOSEPH VON PEIOHL, Director of the Hungarian Navigation Company Adria of
Fiume Hungary do hereby declare the nature of this invention and in what manner
the same is to be performed to be particularly described and ascertained in and by
the following statement :—
It has heretofore been necessary, before adjusting the heeling-error corrector, to
measure the magnetic vertical force on shore and on board in order to ascertain the
relative proportion of both forces, and to regulate it by the heeling-error corrector.
By means of the magnetic balance which forms the subject of this invention
the above mentioned measurement on shore is dispensed with, so that the heeling-
error can be mechanically corrected at sea, and in every position of the ship.
This balance, which is shown in vertical section at Fig. 1 of the accompanying
drawing, consists essentially of a magnet needle a which is generally composed of
two magnets, and which is mounted on a horizontal axis having knife-edges, and is
generally provided with two double scales, either engraved on the sides of the needles
or on unimagnetic wires mounted on and parallel to the needles, each such scale
being provided with a sliding weight, so that there are generally four such sliding
weights, c c d d'.
A plane dividing the knife edges in a longitudinal direction forms a right anglo
with the centre line of the magnet a, such plane being vertical when the needle is in
a horizontal position.
Both the knife edges and their supports are made of hard material such as steel,
agate, or crystal, and the needle has a downward projection a' at its middle in order
to bring the centre of gravity beneath the axis.
Instead of forming the knife edges upon the needle, they may be formed on the
support, in which case the axis rests upon them with V grooves.
The whole is enclosed in a casing g which can be provided with a device for
stopping motion.
Of the two double scales, the one has in each half generally 4 division lines (each
division being equal to the distance of 0 from the fulcrum) in consideration of the
fact that on both hemispheres the maximum of the vertical intensity amounts to about
4 London units (a London unit being understood to be the earth's horizontal force
at London). If the weight e is placed upon division 1 while all the others are" on
zero, the neodle must, when the vertical force is a London unit, assume the horizontal
position, which can be observed by means of the divisions on the arc scales hh_if
applied, or, instead hereof, by means of marks ii arranged at the sides of the
needle.
These scales may however be based on the force of another locality than London, as
unit, which would however require a corresponding alteration of the number of
divisions, as also of the weights c c¹.
The second double scale carries weights d d' which indicate only one tenth that of
the weights cc', and the scale has 10 divisions, each division being equal to the
distance of 0 from the fulcrum the shifting of the weights d d one division,
corresponds to one tenth of the unit on the other scale.
By means of this arrangement the balance receives the requisite sensitivenoss even
with only a limited length of the needle, a.
Balances with longer needles may however be constructed, which have only a
single scale with correspondingly enlarged divisions into units and tenths.

page_text: The weights c c are also in this case so proportioned that they maintain the balance
approximately horizontal if the one thereof is set at zero, and the other at the
numerical value of the vertical force of the corresponding locality.
For the employment of the instrument, it is mounted in a gimbal ring j, the level k
on the top of the glass cover of the balance allowing of the accurate level adjustment
of the whole apparatus, while the removeable sighting pins enable the same to be
adjusted to any angle relatively to the keel line of the ship.
The bearing pins of the gimbal ring can be laid in bearings hanging in adjustable
carrying bands, or the instrument can, as shown in the drawing, be carried by two
adjustable columns to which the gimbal ring is pivotted. For increasing the
stability, a weight may be attached to the bottom of the casing 9.
Lastly, it is to be observed that the balance can also be enclosed in a casing filled
with a liquid and having an air tight cover with valve, and a caoutchouc bag
communicating with the casing at bottom. Into this bag a portion of the liquid is
allowed to descend, when it is required to adjust the weights for a local vertical
force.
Instead of the above arrangement, the balance can also be provided with liquid
brakes, consisting of small metal plates which project down from the middle of the
length of the needle a or from the axis band dip into a vessel filled with liquid.
Fig. 1 shews a vane projecting down from the middle of the needle for this purpose.
Also, as shewn at Fig. 3, liquid brakes can be applied to the pivots of the gimbal
ring in which the balance is hung, such brakes consisting of metal plates n fixed to
the pivots and dipping with their lower, if necessary, widened ends into receptacles o
fixed to the columns and filled with liquid.
The force producing the heeling-error, having been ascertained by the above
described balance, is then compensated by means of the corrector of heeling-orror now
to be described with reference to Figs. 4 and 5.
In these figures the dotted lines shew a binnacle in two vertical sections taken at
right angles to each other. indicates the centre of motion of the compass. Under
this centre is a large vertical magnet q which is adjustable perpendicular to the dock
in the metal frame 1 on the support ŕ of wood or metal, and which can be secured
in position, by a setting screw
In a receiver t, which is adjustable on the magnet 9 and can be fixed by a setting
screw, there are fixed symmetrically and in pairs other vertical magnets, such for
example as the two magnets s ; but several pairs can be used which are arranged
parallel to the keel direction.
The north ends of all these magnets are marked distinctly, and by raising or
lowering as also, if necessary, by turning the same, or the one or the other of same,
every vertical force ascertained by the balance can be compensated, and consequently
also the heeling-error.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. A magnetic balance for directly measuring the magnetic vertical force, con-
sisting of a magnet-needle which can turn upon knife-edges round a horizontal axis
and which carries one or two double scales each with two adjustable weights; the
shifting of a weight on the one scale (in the case where two double scales are used)
to the extent of one division corresponds if not exactly, at least very nearly, to a
known unit of the vertical intensity while the shifting of a weight on the other scale
corresponds to a certain fraction of this unit, so that after adjusting the weights for
the vertical intensity corresponding to a certain locality, the vertical forces of the
ship can be ascertained, which are to be neutralized by means of the heeling-error
corrector.
2. In the magnetic balance referred to in claim 1, the provision of brake-arms on
the magnet needle or on the axis thereof, which dip into a liquid.

page_text: 3. In the magnetic balance referred to in claim 1, the provision of brake-arms on
the pivots of the gimbal ring in which the balance is suspended which arms dip into
a liquid.
DL: 21 dan of T1880
ABEL & IMRAY,
Agents for the Applicant.