Improvements in Ships' Compasses.
Year: 1886

page_text: Improvements in Ships' Compasses.
I, CHRISTIAN FRIEDRICH FERDINAND WILKE of Grünhof Grenzstrasse N° 29
Stettin in the Kingdom of Prussia Master Mariner 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:-
This invention refers to a new construction of compass wherein the compass card
is fixed to and movable with its pivot, moving only in a horizontal direction. The
magnet is made in the form of a ring which is perfectly movable in the vertical as
well as the horizontal direction and the compensating arrangement connected
therewith moves with it; this latter does not act on the pointing power so as to
weaken it but to strengthen it.
The drawing is a vertical section through such a compass.
The compass is contained in a bowl or case a which is filled with clarified rape
oil and may terminate in a half sphere below. The case is hung in Cardan
gimbals in the ordinary manner and provided with a glass cover.
Underneath the
compass card d is provided a cover b which is screwed into the case a. On this
cover b is provided a small well fitting cap c provided with a hole at the top.
The pivote of the compass card goes through this hole in the cap and down
through a hole in the cover b and is fixed to a plate m secured to a turned soft
wrought iron ring U-shaped in cross section. At the bottom of this ring lis
another plate m which is fixed thereto. Onto this lower plate m¹ is fixed a
pivot e¹, which is in line with and forms a continuation of the upper pivot e fixed
to the card, and which turns in a step n fixed to the bottom of the bowl or case a.
Inside of the U-shaped ring is placed a ring h which consists of two half rings
one of which is made of round magnetized steel and the other of soft round iron.
Both parts or halves are of the same thickness and are pinned together. The
upper half forms the magnet and the lower half the armature. The said ring is
covered with copper wire in such a manner that about 1 millimetre play is allowed
between it and the U section ring Ɩ which allows the magnetic apparatus to put
itself into the corresponding inclination.
Inside and at right angles to the aforesaid steel and iron ring is placed an
elliptical brass ring k. (As the thickness and proportion of this ring is not settled
by other parts it may be made of such a weight as to produce equilibrium).
Inside of this brass ring k and at right angles thereto are placed two concentric

page_text: copper plates or rings g and g¹ of equal thickness which are soldered onto the out-
side of a hollow copper sphere f, the shell of which is about 2 millimetres thick.
The copper rings are soldered on at a short distance from each other and the
copper ball is divided thereby into two equal parts. On the outside of the ball ƒ
and between the copper rings g and g¹ is wound a copper wire i about 1 millimetre
thick and is also closely wound round the magnetic ring hin left handed coils.
The ends of the wire are soldered together so that the covering of that part of the
ball and the magnetic ring consist of one endless wire. These five parts vizt, the
copper ball f, the copper rings 9, the magnetic ring h, the copper wire coils i
between the copper rings and the elliptical brass ring k form together the magnetic
apparatus and are so arranged that their weight equalizes their flotation power in
oil and the centre of gravity of the whole apparatus lies in the centre of the ball f.
Soldered or fixed on to the small plate m on the top of the U shaped ring is a
hollow cylindrical body o made of sheet brass the bottom of which is in the form
of part of a sphere concentric with the ball. This cylinder forms the float. It is
fixed to the U shaped ring by a nut on the pivot e. The cubic contents of the
float are so arranged that its flotation power just supports the weight of the same
and the parts connected thereto so that the lower pivot e¹ only presses on its step
with a very slight weight say of about 1 gramine.
The object of this arrangement is to hinder the radiation of the magnetic lines of
force on the adjacent iron parts and the deviation arising therefrom. The parallel
running lines of force in the magnet are led into the armature. The diverging
lines of force set up induction in the wire coil h and are led into the wire coils i
between the copper rings g and g¹, where the currents act vertically to the
magnetic direction, and while induction is set up in the copper rings pass off onto
the surface of the copper ball without doing harm as regards deviation.
The oil in which the whole apparatus floats serves as insulator for the conductor
wire and the U shaped iron ring & serves as a conductor for the magnetic ring h,
and acts with reference to the magnetic power action as a shield.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
First: A compass card which moves only in the horizontal direction and is
mounted substantially as described and shown.
=
Second A ring-shaped compass magnet which is movable in the vertical as
well as the horizontal direction and which carries the compensating appliance with
it substantially as described and shown.
pro-
Third-In a compass the card d, fixed on a pivot which has its bearing in the
upper part of the bowl or case a containing insulating liquid, and is united to the
soft iron ring which latter at its bottom part is stepped in the bowl a and is
vided with a float for taking the load off the said step, in combination with a
compound magnet ring and armature h provided with endless copper wire coils
which are continued round a space between two copper rings mounted on a hollow
ball which is united to the ring h by a non-magnetic connection substantially as
and for the purposes set forth.
Fourth The construction of compass shown on the drawing.