Improvements in and relating to the Mariners' Compass.
Year: 1891

page_text: Date of Application, 16th Oct., 1891
Complete Specification Left, 15th July, 1892-Accepted, 27th Aug., 1892
PROVISIONAL SPECIFICATION.
Improvements in and relating to the Mariners' Compass.
WILLIAM DAVID WHYTE 144 Broomielaw Street, Glasgow, Compass Maker,
and JAMES THOMSON 144 Broomielaw Street, Glasgow, Compass Maker, do hereby
declare the nature of this invention to be as follows:-
The object aimed at in this invention is to prevent disturbance of the compass
card by vibration caused by the engines, propeller, gun firing &c. and is attained
thus:-
First. Improvements in the construction of the frame of the compass card.
Second. Improvements in the suspending of the compass bowl and the means of
checking the vibration.
Third. An improved azimuth instrument or obtaining bearings and ascertaining
the errors of this compass.
The compass card consists of a light circular metel rim, connected with a centre
circular plate by means of four metal spokes.
Four pieces of round aluminium wire are cut to the length required then they
are hammered flat, at one end the metal is left flat for about inch, then the spoke
is twisted until the edges are end up and down, then the spokes are bent downwards
in a curve from the end, which connects them to the centre plate, until it comes to
within 2 inches from the metal rim, then it becomes straight and is rivited at both
ends to the rim and the centre plate, and so unites the frame.
Then a light flat ring is connected by four wires to the outer end of the rim, and
when in proper position, it is suspended about two inches below the card, and is
for the purpose of carying the magnets.
The object of making the spokes above described, is to obtain the greatest
possible strength of the frame work with a light and soft metal, and the object of
the flat circle is for holding the magnets, is, that being below the centre of gravity
in the compass, and the weight thrown out by the four wires to the outer edge of
the rim, and the magnets being on a circle are more evenly balanced, and so causes
the card if disturbed, to regain its balance more quickly than if the magnets were
fixed to the spokes, as is usually done.
The second improvement in the frame work is, or fixing the paper print which
represents the compass points etc.
A very fine wire is fixed to one of the spokes at the north-west point of the card,
then it is drawn tight and extended in a straight line across to the next spoke, over
the north-east point, it passes through the rim and continues in another straight line
to the point south-east, it passes again through the rim and thence to the point
south-west, it passes again through the rim and thence to north-west, and is fixed
after being drawn tight.
The object of doing so is, the paper print is fixed on to the outside of the rim by
cement, an laid on the flat surface of the rim, but there being nothing but the
spokes to support the paper, it falls down slightly, or becomes by exposure to heat
or damp etc., wrinkled and so presents an uneven surface, but when the paper is
lying on the wire before described, and fixed by small gumed slips of paper, across
the wire, then on to the print, it unites the two together, and so keeps the paper
perfectly flat and always in its place.
The improvements in the compass bowl for checking vibration are, the bowl is
made in two parts, one outer and one inner, on the bottom of the inner bowl is
fixed a spiral coil of brass wire, formed so as to make a spring when it is fixed to
the outer bowl, the inner bowl is then fixed to the outer one, and it is so adjusted
that it rests on the spring, four pillars are then attached to the inner bowl, and are

page_text: brought through the flange of the outer bowl and fixed, and so practically unites
the two bowls.
The idea of constructing them in this way is, when any vertical vibration occures
on the vessel, the binnacle being fixed to the deck, transmits the motion to the
compass, but the inner bowl resting on the spring, destroys the effect and the
card (which is balanced on a pivot inside of the inner bowl) is not disturbed.
A large ring is hung inside the binnacle by three or four chains, attached to the
brass rim of the wood binnacle, then attached to the ring are two spiral springs,
the springs are made thus, a solid rod is made the correct length, then an adjusted
spring is coiled round this rod and fixed at the bottom, at the top of the spring is a
thick brass flange into which the top part of the spring is fixed; then over the
spring and flange, is a tube which is fixed on to the flange and works with the
spring then the rests for hanging the compass, are fixed on to the top of the outside
tube, and so make an easy rest for the compass knife edges.
The pillar or rod keeps the spring in its place, and a bush at the bottom, steadies
the tube which is fixed to the spring, when the weight of the compass is on the
rests, it contracts the two spiral springs, (which the knife edges of the compass on
both sides rest on), and the whole instrument is now sitting on a combination of
springs.
By this arrangement the vibration is all ways checked and the card is always
steady, which is the object of this invention.
In cases where a smaller size of binnacle is more suitable we prefer to do away
with the large ring and simply employ the springs by fixing them on the bottom of
the binnacle with a large flange.
The third improvement is for the purpose of taking bearings and for ascertaining
the errors of the compass.
A tube is fixed on a frame which rests on the centre of the compass glass, and is
angled so, that when looking down through it, the points and degrees of the card
are visible.
A mirror is fixed on the upper end of the tube, on the top of it by which the
observer is enabled to get a reflection of any visible object, there is a wire fixed
exactly in the centre of this mirror which constitutes the true centre of the instru-
ment, a small pointer is fixed at the foot of the tube, which is exactly in a line
with the wire on the mirror, you then look down the tube, and the pointer gives
you the compass bearing of the object, when it is split by the wire in the centre of
the mirror.
Dated this Twelfth day of October 1891
WILLIAM DAVID WHYTE.
JAMES THOMSON.
COMPLETE SPECIFICATION.
Improvements in and relating to the Mariners' Compass.
We, WILLIAM DAVID WHYTE, and JAMES THOMSON, of 144 Broomielaw
Street, Glasgow, Nautical Instrument Manufacturers, 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 relates to the mariners' compass, and it has for its object to
improve its construction.
And in order that our said invention may be properly understood, we have
hereunto appended two explanatory sheets of drawings, whereon :-
Fig. 1 is a plan view of the compass card.
Fig. 2 is a view looking on the back of the card.
Fig. 3 is a cross section, on the line a-x, Fig. 1.
Figs. 4 and 5 are detail views.
Fig. 6 is a section of part of the binnacle.
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page_text: Fig. 7 is a plan of the binnacle, with the cover removed.
Fig. 8 is a part vertical section, at right angles to Fig. 6.
Fig. 9 is a detail view.
Figure 10 is a side view, and Fig. 11 a plan, of an azimuth instrument.
Referring to the drawings, whereon the same reference numerals, wherever
repeated, indicate similar or like parts:-
The improved compass card is made up of a light circular metal rim 1, of preferably
"angle" section. On the rim 1 is secured a light paper "card" 2. upon which the
usual "points" are printed. The card 2, which may be made of fine "India" or
"bank-note" paper, so as to give a maximum of strength, with a minimum of
weight, is cut out, at the centre, as shown at Figs. 1 and 2, and is, or may be,
secured to the rim 1, by being folded over said rim and then cemented or pasted
(see enlarged detail, Fig. 4). The rim 1 is connected, preferably, by four
aluminium or other light metal spokes 3, to a central plate 4, of aluminium or like
suitable metal. The spokes 3 are preferably made of pieces of round aluminium
wire, which are first cut to the lengths required, and are then hammered out flat,
and so as to be broad and thin. At one end, 3*, the metal spokes are left flat for
about of an inch; then they are twisted round until the edges are in the vertical
position, so that the spokes are now narrow and deep, then they are bent downwards
in a curve (see 35 Fig. 3) from the ends 3ª, where they are connected to the centre
plate 4, up to within about 2 inches from the metal rim 1, where they are again
straight (see 3). The spokes are, preferably, riveted at both ends 3º, 3º, to the
centre plate 4, and the rim 1, so as to unite and render the frame rigid. The
straight parts 3d of the metal spokes serve to support the card 2.
A light flat or "angle"-sectioned ring 5 is connected, by four thin wires 6, to
the rim 1. When the ring 5 is in its proper position, it hangs in the centre and a
little below the level of the card 2. The magnetic needles 7, of which there may
be any desired number, are carried in the ring 5, being secured in holes therein.
There is also secured to the rim 1, four very thin and fine wires 8, which are
stretched across the frame as chords of a circle, and so as to support the paper
print 2. The wires 8 are secured to the paper, by small pieces of gummed paper 10.
The wires 8, which may pass through holes 9 in the rim, and be bent and twisted
so as to secure them in place, are drawn as tight as possible. One wire may pass
from, say, the N.W. point to the S.W. point, another from the N.W. to the
N.E. point, a third from the N.E. to the S. E. and a fourth from the S.E. to the
S.W. point. Instead of having four separate wires, a single wire may be threaded
through the rim at the several points.
The object of making the spokes 3 as before described, is to obtain the greatest.
possible strength and rigidity of frame, with a light and soft metal.
The object of using the flat circle 5 for holding the magnets, is, that, as it is
suspended below the centre of gravity of the compass, and, as the weight is
transferred, by the four wires. to the outer edge of the rim, and also, as the
magnets are more evenly balanced, since they are secured to a circle, as a con-
sequence, the card, if disturbed, regains its equilibrium more rapidly than if the
magnets were fixed to the spokes, which is the usual method.
The object of using the wire or wires 8, is that, as the paper print 2 is fixed on
to the outside of the rim 1 by cement or paste and then laid on the flat surface 1°
of the rim, and, as there is nothing but the straight parts 3d of the spokes to support
the paper 2, it falls down slightly or becomes wrinkled, by exposure to heat or
damp etc., and so presents an uneven surface. When, however, the paper is laid
on the wires 8, and secured thereto by the small gummed slips 10, the paper 2 is
kept perfectly flat and always in its place.
The compass bowl is made in two parts 11 and 12 (see Figs. 6 and 7). The
inner bowl 12 being secured within the outer bowl 11. The inner bowl 12 has a
spiral spring 13 secured to its underside, and which rests on the centre of the outer
bowl 11. This spring 13 supports the weight of the inner bowl 12. The outer
bowl 11 has a tee-shaped ring 14 on its rim, through which pass, preferably, four

page_text: small bolts or pillars 15, (see enlarged view at Fig. 9). These bolts 15, which also
pass through holes in the flanged rim 20 of the inner bowl 12, have screw nuts 16
at their upper ends, for adjusting purposes. The screw nuts 16 can be clamped in
position by pinching screws 17. Spiral springs 19 are so fitted on the lower ends
of the bolts 15, as to bear against the rim 14 of the bowl. 11, and also against
collars 18, made on the bolts. The degree of tension of the springs 19, can be
regulated by the screw nuts 16.
21 is the glass cover of the bowl 12. 22 indicates, in dotted lines, the compass
card, which is supported on a spring pivot 23.
The bowl 11 has, on its outside, two pivots 24, 25, which work in bearings 26,
secured to the inner side of a ring 27. The ring 27 has knife edges 28, 28, which
are supported in bearings 29, made on the upper ends of vertical rods 30. These
-rods pass through guide slots 31, 31, made in a large ring 32, which is hung by four
small chains 33, to, preferably, the brass rim 39 of the wood binnacle 34. The
ring 32 has two downward extensions 35, 36, which are made with feet 37 at their
lower ends. Holes are made in the feet 37, to guide the bars 30. 38, 38, are
spiral springs, which pass round narrowed or reduced parts 30% of the bars 30. The
bars 30-30 are supported by the springs 38, 38, which bear, at their upper ends,
against the broad parts 30. If so desired, the springs 38, 38 may be secured at
their upper ends to the ring 32, and be attached to the bars 30, 30, at their lower
ends.
With this arrangement, the instrument is supported on a combination of
springs 13, 19 and 38, 38, so that any vibration is checked or minimised, and the
card is always steady.
In cases where a smaller binnacle is desired, we prefer to dispense with the
ring 32, and use guide brackets 50 (see dotted lines Fig. 6) at top and a flange 51
at the bottom for the rods 30-30 and springs 38, instead of the ring 32 and
extensions 35.
Figs. 10 and 11 show an instrument for taking bearings for ascertaining the
errors of the compass. The instrument consists of a tube 40, which is supported on
a frame 41, having a centre 42, which turns in a socket 43 on the compass glass 21.
The tube 40 is at an angle of, preferably, 40° to the horizontal. Fitted on the
tube 40, is a movable mirror 44, by the aid of which the observer can get a
reflection of any visible object. The mirror is swung in a forked bracket, and is
capable of vertical movement. A wire, thread, or equivalent, 45, is stretched
across the long diameter of the mirror, which latter is, preferably, of elliptical
shape. This wire 45 is on the exact centre-line of the tube 40, so that it constitutes
the exact centre of the instrument. 46 is a shade mounted on a universal joint 47,
so as to be capable of being moved about in any direction. 48 is a sight, formed of
the usual slotted bar. 49 is a small pointer, which moves along with the instru-
ment. 50 is a counter-balance weight. The azimuth instrument is balanced on the
centre 42.
When it is desired to take observations, the instrument is turned round, until the
object is reflected on the mirror, and the image is bisected by the wire or thread,
stretched across the mirror. When the image is bisected, the observer looks
through the tube, and the pointer 49 gives the compass bearing of the object.
Instead of using two bowls, only one may be employed, and other structural
alterations may be made, without departing from the invention.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that wh..t we
claim is :-
1. The improved compass card, substantially as hereinbefore described, with
reference to Figs. 1 to 5 of the drawings annexed.
2. The combination of the ring 32 or its equivalent, rods 30-30°, springs 38 and
extensions or equivalent 35, 36, substantially as hereinbefore described and shown
on the drawings annexed.

page_text: 3. The combination of the compass bowl 12, spring 13, outer bowl 11, ring 27
and rods 30-30° and springs 38 supported on extensions, or equivalent, attached
to, or made one with, a second ring 32, hung by chains, or equivalent, within the
binnacle, substantially as and for the purpose hereinbefore set forth.
Dated this 14th day of July 1892.
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent.