improvements relating to Magnetic Compasses and their Accessories.
Year: 1893

page_text: Date of Application, 7th Sept., 1893
Complete Specification Left, 7th June, 1894-Accepted, 18th Aug., 1894
PROVISIONAL SPECIFICATION.
improvements relating to Magnetic Compasses and their
Accessories.
I DUNCAN MCGREGOR Junior residing at 48 Maxwell Drive Pollokshields
Glasgow, Nautical Instrument Maker do hereby declare the nature of this
invention to be as follows :—
This invention consists of a mariners compass constructed in an improved form
having one or more spring attachments for suspending same in the binnacle. The
needles of the card are shorter than those in general use and the card itself may be
arranged to work in a transparent fluid, or in a dry bowl fitted underneath with a
chamber containing viscous fluid.
The containing binnacle stand is made in whole or in part of brass or of some
other suitable material, or partly of wood and has if made in a combined form the
upper part formed of brass with a hollow centre for containing a heeling magnet,
and the lower portion of wood for containing the magnets for correcting the semi
circular deviation. Quadrantal correctors and a Flinders bar are also attached to
the binnacle stand.
If the compass is to be used inside a wheelhouse the binnacle cover is made low
in shape having a glass on top either perfectly flat or fitted in the cover at an angle
and a lamp of an improved form is fitted partly over the glass. This lamp in which
either oil or the electric light may be used has an attachment for shewing by night
and by day, by means of a moveable compass disc or by letters and figures the
course the vessel is to be steered.
If the compass is to be used on deck in the open air a binnacle cover of a bigher
form having one or more lamps and the course indicating apparatus is used instead.
Dated this Sixth day of September 1893.
COMPLETE SPECIFICATION.
Improvements relating to Magnetic Compasses and their
Accessories.
I, DUNCAN MCGREGOR, Junior of 48 Maxwell Drive, Pollokshields, Glasgow,
do hereby declare the nature of my invention, and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement in writing, that is to say:―
This invention consists of a mariner's compass constructed in an improved form
having one or more spring attachments for suspending same in the binnacle. The
needles of the card are shorter than those in general use and the card itself may
be arranged to work in a transparent fluid or in a dry bowl fitted underneath with
a chamber containing viscous fluid. The containing binnacle stand is made in
whole or in part of brass or of some other suitable material or partly of wood and
has if made in a combined form, the upper part formed of brass with a hollow
centre for containing a heeling magnet, and the lower portion of wood for containing
the magnets for correcting the semi-circular deviation. Quadrantal correctors,
globes or brass boxes and a Flinder's bar are also attached to the binnacle stand.
If the compass is to be used inside a wheelhouse the binnacle cover is made low in
[DᏗ 1

page_text: shape having a glass on top either perfectly flat or fitted in the cover at an angle,
and a lamp of an improved form is fitted partly over the glass. This lamp in which
oil, or the electric light may be used has an attachment for showing by night and.
by day by means of a movable compass disc or by letters and figures the course the
vessel is to be steered. If the compass is to be used on deck in the open air a
binnacle cover of a higher form having one or more lamps, and the course indicating
apparatus, is used instead.
And in order that my said invention and the manner of performing or carrying
the same into effect or practice may be properly understood, I have hereunto
appended an explanatory sheet of drawings in which the same reference letters are
used to indicate corresponding parts in the several figures where shown.
Figure 1 is an elevation and Figure 2 a plan view of a magnetic compass and
its accessory fittings as constructed and arranged in accordance with my
improvements.
Figure 3 is an elevation, partly in section, at right angles to the view shown in
Figure 1, while
Figure 4 is a horizontal section as taken on the line 3-3 of Figure 3.
Figures 5 and 6 are detached views showing a sectional elevation and plan view
respectively of a compass card, with the spring and magnet attachments. While
Figures 7 and 8 are detached vertical and horizontal sections respectively of a
lamp and its fittings as constructed in accordance with my improvements.
Figure 9 represents a front view of a modified arrangement with duplex lamps.
Referring to these drawings:-A is the bowl or binnacle and A the binnacle
stand. The upper part of this stand A' is made of brass or other suitable material
and is formed with a central vertical hollow channel or recess a in which is fitted a
brass tube, as shown in Figure 3, to contain a heeling magnet a'. This heeling
magnet a¹ is preferably connected at its upper end to a chain a³, so that its position
can be adjusted by raising or lowering this chain and securing it at any desired
height on to a hook or other fastening at a. The lower portion of the stand A'
would be made of wood at A', and said wood would be formed with a series of holes
arranged in alternate layers at right angles to each other to contain magnets b, b',
as seen in Figures 3 and 4, for correcting the semi-circular deviation. The ends of
these holes are closed by wood or strips of non-attractive metal. C, C, are bracket
arms secured to the binnacle frame A, and at their outer ends carry quadrantal
correctors which may be iron globes C¹ secured by bolts C, as shown in Figure 1,
but the bracket arms C may be made flat on top and the globes C¹ be adjustably
moved along a groove in same and be fixed in any adjusted position; while a
Flinder's bar case D with non-magnetic iron bar D', formed in one or more pieces,
is secured to the stand A', as shown in Figure 3. Or the stand may be made
altogether of brass cast hollow with the heeling magnet tube a fitted in same, also
tubes at right angles for containing the magnets for correcting the semicircular
deviation together with the Flinder's bar and quadrantal corrector fittings.
Referring to Figures 2, 5 and 6 the compass card is made as follows, I first
make a circular outer rim or frame of aluminum or other light and suitable material.
In the centre of this a light metal collar E' is made for containing the ordinary
jewelled cap this collar being connected to the outer circumference rim of the
compass card E, by curved wire springs e which also support the cradle in which
the direction magnets are fitted. This cradle is composed of two aluminum
rings ee. The inner one has holes drilled in it at the distance the direction
magnets are placed from each other. When the ends of the magnets e are placed
through these holes, the inner ring e¹ is placed inside the outer ring which abuts
against the ends of the magnets and keeps them in position. The two rings el e
are then connected to each other by wire binding or small metallic flaps e. By
this means the compass needles or direction magnets are kept securely fixed in
their proper position without the aid of solder, cement, or other process. A mica,
paper, or cloth print showing the points and markings of a compass card is then
fixed to the outer aluminum ring et. F represents a lamp supported on the top of

page_text: binnacle frame A and said lamp may be an oil lamp, as shown in Figures 7 and 8,.
or it may be lighted by electric or other suitable light. It can also be lifted away
off the supporting horns when required. In front of this lamp F is fitted a movable
disc or card for showing by day and by night the course the vessel is to be steered..
This course to steer disc fis made of glass, mica, or other suitable transparent.
material and is preferably fitted to the frout vertical cover F' of the lamp and bas
a glass fin front of it. This disc fis turned by a hand spindle f*, operated by a
movable key which is taken away when the course is set, and set to the course.
desired opposite a fixed hand or pointer F3, shown in Figure 1, and the disc can be
kept in any desired fixed position by means of a screw nut f³ outside the glass.
cover f. Instead of moving the disc fit may be held stationary and the pointer F
be made the movable organ, but other equivalent means of arranging and operating
the course to steer disc or organ may be substituted. Swivelling sheet metal
segmental flaps may be mounted in front of the glass cover f¹ so as to only leave
exposed a limited part of the disc opposite the course to steer pointer A. This
lamp or course to steer indicator may be placed on various parts of a ship's compass
stand or binnacle and I do not limit my claim to the position as shown in the
drawings. The course to steer indicator may be applied behind the front pro-
tecting glass of the ordinary ship's binnacle, a water tight aperture being made in
same to receive the setting screw, or it may be placed on top of ordinary binnacle
covers in a vertical or in a slightly sloping position either wholly or partially
exposed to view.
By another method, as shown in Figure 9, the indicator may be placed above
the protecting glass, in which case the binnacle protecting glass F" is made smaller
and the ordinary binnacle lights F illuminate the dial at night.
I am aware that small compass cards alone have been placed horizontally upon
the top of ship's binnacles and used for taking bearings, and I make no claim to
such.
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 :-
First. The construction or arrangement and combination of the parts of a.
magnetic compass and its accessories, substantially as herein described in reference
to and shown in the accompanying drawings.
Second. In combination with a magnetic compass, a compass card, direction
magnets, and spring attachments made and arranged as described.
Third. In combination with magnetic compass the arrangement and use of a.
heeling magnet together with a Flinder's bar and semicircular deviation correcting
magnets at right angles to and underneath each other along with iron spherical
quadrantal correctors substantially as herein described in reference to and by way
of application shown in accompanying drawings.
Fourth. A lamp or light in combination with a course to steer indicator arranged
substantially as and for the purposes herein described.
Fifth. In combination with a magnetic compass a lamp or light and a course to
steer indicator arranged substantially as and for the purposes herein described.
Dated the 6th day of June 1894
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.