Improvements in the Mariner's Compass.
Year: 1891

page_text: Date of Application, 17th Sept., 1891
Complete Specification Left, 17th June, 1892-Accepted, 30th July, 1892
PROVISIONAL SPECIFICATION.
Improvements in the Mariner's Compass.
I JAMES MORTON of Villiers Street South, Sunderland in the County of
Durham, Compass Maker, do hereby declare the nature of this invention to be as
follows:-
:-
My invention relates to certain improvements in the mariner's compass and has
for its objects,-
1st. To so construct a compass card that it shall be sufficiently rigid but never-
theless lighter than any hitherto devised with the consequent advantage of being
more sensitive owing to the reduction of friction at its point of suspension.
2nd. To increase the magnetic forces directing and controlling all the motions of
a compass card; and thus produce a mariner's compass which shall be sensitive
steady and reliable in all circumstances.
Firstly, The materia! I use for the card is paper, sheet aluminium, or other
very thin light material which I stiffen and render rigid by corrugating ridging or
embossing it in any effective direction or directions, and either continuously or
otherwise. The finished card thus prepared may be either disc-like, or partly disc-
like and partly coned, or of the annular form suspended from its centre point in the
known manner.
In carrying out this part of my invention I take a disc of the material and by
ordinary mechanical pressure stamp or emboss it to the required form and diameter
at one operation; or I may form the material into a cone or cup the rim of which
is of the diameter required for the completed card, and this cone by pressure or
otherwise I fold or corrugate into any convenient number of ridges either all
concentric, or partly concentric and partly radial, for example the outer part may
be concentrically ridged and the inner coned part left either plain or ridged. The
ridges may be continuous or at intervals as may be advisable in regard to the
diameter or other circumstances.
All such concentric corrugations or ridges will come within the limit of the
length of the original cone, that is, the sum of their lengths will be equal to that
of the cone and they take the same angle or slope as the original cone: thus the
material is not liable to be strained or stretched in any direction, and the section
of the finished card may be modified to any form between the original cone and a
corrugated disc.
To further stiffen the card it may be made up of separate sections or rings
alternately corrugated radially and concentrically and afterwards joined together
to form the complete card, which is jewelled in the usual way at its central bearing
point.
Having thus constructed the card I attach to it very thin aluminium tubes each
containing one or more short magnetic needles and arranged parallel to the N and
S line and as far from the centre as practicable so as to throw the weight to the
periphery and so increase its inertia.
The tubes are made a little longer than the needles and closed by flattening each
end which is then pierced for attachment to the card in the required positions. By
this method there is no necessity to bore the needles and thus they are more perfect
magnets.
Secondly. In order to increase the magnetic force directing and controlling all
the motions of a compass card, instead of using only one magnetic compass as has
always hitherto been the practice I employ two or more compasses, magnetic,
needles, or a combination of same superposed and balanced on separate and
independent centre points in the same vertical line in such manner as to be free to

page_text: move in azimuth and thus I obtain a force and effect equal to the sum of the
powers of all the magnetic needles employed; and in order to make the combined
needles cooperate to limit the period of vibration one of another and so bring the
card to rest as speedily as is desirable and ensure steadiness of the compass, I
apply a fluid. brake to one or more of the said needles of the combination by wholly
immersing same in a bowl or bowls of liquid of suitable viscosity but quite inde-
pendent of the suspended card the magnets of which may be arranged either inside
or outside of the, combined needles, and either in the same horizontal line therewith
or not as most convenient.
D
" a
T
J. C. CHAPMAN;
Agent.
COMPLETE SPECIFICATION.
Improvements in the Mariner's Compass.
I JAMES MORTON of Villiers Street South, Sunderland in the County of
Durham, Compass Maker, do hereby declare the nature of this invention and the
manner in which the same is to be performed to be particularly described and
ascertained in and by the following statement :-
My invention relates to certain improvements in the mariner's compass and has
for its objects,―
1st. To so construct a compass card that it shall be sufficiently rigid but never-
theless lighter than any hitherto devised, with the consequent advantage of being
more sensitive owing to the reduction of friction at its point of suspension.
2nd. To increase the magnetic forces directing and controlling all the motions of
a compass card, and thus produce a mariner's compass which shall be sensitive
steady and reliable in all circumstances.
In fully describing my invention I will refer to the accompanying drawings
which form part of this Specification, and in which similar letters refer to similar
parts.
Firstly. The material I use for the card is paper, sheet aluminium, or a combina-
tion of the two, or any other very thin light material; this I stiffen and render
rigid by corrugating, ridging, or embossing it in any effective direction or directions,
and either continuously or otherwise.
The finished card thus prepared may be either disc-like as in Figure 6, or partly
disc-like and partly coned as in Figures 7 to 12; or of the annular form suspended
by threads or wires from its central boss in the known manner, as illustrated in
Figures 13 to 16. In carrying out this part of my invention I take a plain flat
disc of the material, which may be printed with the required signs, and by ordinary
mechanical pressure I fold corrugate or emboss it to the required form and
diameter; or I may form the material, previously printed or not, into a cone or cup,
such for example as is represented in section at a Figure 1, the rim of which is of the
diameter required for the completed card; this cone by pressure or otherwise I fold
or corrugate into any convenient number of ridges-either all concentric with the
central boss as at c in the figures, or partly concentric as at c and partly radial as
at in Figures 7 to 16; for example, the outer part may be concentrically
corrugated ate and the inner coned part a left either plain as shown in Figures 7
and 8, or radially ridged' as shown at r in Figures 11 and 12.
Such ridges may be continuous or at intervals, or tangential to the centre cone
as in Figure 9, or arranged like the vanes of a turbine as in Figure 10, or other-
wise as may be advisable in regard to the diameter or other circumstances.
All concentric corrugations such as c. c. will come within the limit of the length
of the original cone a, that is, the sum of their lengths will be equal to that of the
cone, and they will take the same angle or slope as the original cone, as plainly
illustrated in Figures 1 to 8: thus the material is not able to be strained or

page_text: stretched in any direction, and the section of the finished, card may be modified, to
any form between the original cone of Figure 1, and a corrugated disc such, as
Figure 6.
To further stiffen the card it may be made up of separate sections or, rings
alternately corrugated radially or concentrically and afterwards. joined together
to form the complete card, as well shown in Figure 12; the angles, of the corruga
tions, or junctions of sections, or the outer rim, or any or all of the same may, be
further stiffened and strengthened by the application thereto of an extra thickness.
of the metal or material; for example, in Figures 7 and 8 s. s. represent in section
rings or zones of such additional stiffening material, and in the open-centre design
of Figures 13 and 14; the inner edge is shown as laid over a ring of wire w, and
such stiffening will always be applied at the parts liable to be subjected in use to
strains.
The card whether solid or annular is jewelled in the usual way at its central
bearing point.
Having thus constructed the card. I attach. to it very thin aluminium tubes t. t,.
Figures 11-13 and 15, each containing one or more short magnetic needles and
arranged parallel to the N and S line, and as far from the centre as practicable
so as to throw the weight to its periphery and so increase the inertia of
the card.
The figures show various arrangements of these needles, some continuous, and
some in N and some in S part of the card. The tubes are made a little longer
than the needles and closed by flattening each end which is then pierced for attach-
ment to the card in the required positions. By this method there is no necessity to
bore the needles, and thus they are more perfect magnets.
Secondly. In order to increase the magnetic force directing and controlling all'
the motions of a compass card, instead of using only one magnetic compass (as has
hitherto been the practice) I employ two or more compasses, magnetic needles, or
a combination of same superposed and balanced on separate and independent centre
points in one and the same vertical line, in such manner as to be free to move in
azimuth; and thus I obtain a force and effect equal to the sum of the powers of
all the magnetic needles employed; and in order to make the combined needles
cooperate to limit the period of vibration one of another, and so bring the card to
rest as speedily as is desirable and ensure steadiness of the conipass, I apply a fluid
brake to one or more of the said needles of the combination by wholly immersing
same in a bowl or bowls of non-freezing liquid of suitable viscosity, but quite
independent of the suspended card the magnets of which may be arranged either
inside or outside of the combined needles, and either in the same horizontal line
therewith or not as most convenient.
One simple arrangement of this part of my invention is illustrated in section at
Figure 17. M is a magnetic compass immersed in fluid in a bowl d which may he
covered with glass as illustrated at g; vertically above M is centred a
yolk "
bearing at either end the additional needles m m, the respective poles being as
illustrated by the letters N. S. and the needles m m being affixed upon the card as
described.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is;-
1. A mariner's compass card consisting of a disc or ring of paper aluminium or
equivalent very thin light material having formed thereupon wholly or in part as
required corrugations or ridges concentric with the central boss substantially as and
for the purpose set forth.
2. A mariner's compass card consisting of a disc or ring of paper aluminium or
equivalent material having formed thereupon a combination of concentric corruga-
tions and radial ridges disposed alternately or otherwise in any effective direction,

page_text: I t
and provided or not with additional stiffening appliances where required, all sub-
stantially as and for the purposes set forth.
3. In a mariner's compass card the use in combination of circular or concentric
corrugations such as c and radial tangential or other ridges such as ras and for the
purposes hereinbefore set forth.
4. In a mariner's compass card the use of very thin aluminium tubes each serving
'to contain one or more short magnetic needles and disposed and arranged substan-
tially as and for the purposes set forth.
5. In a mariner's compass the use of two or more compasses, magnetic needles,.
or a combination of same, superposed and balanced on separate and independent
centre-points all in one and the same vertical line, one or more of said needles
being immersed in a suitable fluid, all substantially as and for the purposes set
forth
Dated this 17th day of June 1892.
For the Applicant,
J. C. CHAPMAN,
70, Chancery Lane, London, Chartered Patent Agent.