IMPROVEMENTS IN THE MARINER'S COMPASS
Year: 1854

page_text: LETTERS PATENT to Robert John Keen, of Liverpool, in the County of
Lancaster, Nautical and Optical Instrument Maker, for the Invention of
"IMPROVEMENTS IN THE MARINER'S COMPASS."
Sealed the 16th January 1855, and dated the 29th July 1854.
PROVISIONAL SPECIFICATION left by the said Robert John Keen at
the Office of the Commissioners of Patents, with his Petition, on the
29th July 1854.
I, ROBERT JOHN KEEN, of Liverpool, in the County of Lancaster, Nautical
and Optical Instrument Maker, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MARINER'S COMPASS" to be as follows:-
The Invention is intended to counteract the effect of the pitching and
rolling of vessels, and vibratory action in steam vessels; and consists in
adapting india-rubber springs of a particular construction to the cap, and in
the adaptation of a double action metallic spring to the centre, with metal
springs to the pivots and shoulders of the compass.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert John Keen in the Great Seal Patent Office on the
29th January 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
JOHN KEEN, of Liverpool, the County of Lancaster, Nautical and Optical
Instrument Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of July, in the year of our Lord
One thousand eight hundred and fifty-four, in the eighteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Robert John Keen, Her special licence that I, the said Robert John Keen,
my executors, administrators, and assigns, or such others as I, the said Robert
John Keen, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN THE MARINER'S
COMPASS," upon
the condition (amongst others) that 1, the said Robert John
Keen, by an instrument in writing under my hand and seal, should particularly
describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Robert John Keen, do hereby declare the
nature of my said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement
thereof, reference being had to the Drawings hereunto annexed (that is to
say):-
My Invention is intended to counteract the effect of the pitching and rolling
of vessels, and the vibratory action in steam vessels; and consists,-
First, in adapting a peculiar construction of india-rubber disc spring to the
cap of the compass.
Second, in adapting a double action metallic spring to the centre, on which
the compass card is supported.
And, third, in adapting metal springs to the pivots and shoulders of the
.compass.
Figure 1 of the Drawings annexed is a vertical section, and Figure 2 a
plan, of a binnacle compass combining my several improvements; Figure 3 is

page_text: a plan of the cap detached. A is part of the binnacle, in which the compass
is fixed; B is a half gimbal, formed of brass, and attached to the binnacle
at C. This forms the springs for the pivots and shoulders of the compass, the
ends being left free, so as to be capable of yielding to any lateral motion. I
do not, however, confine myself to the use of a half gimbal, as other con-
structions of springs may be employed to effect the same object.
D is a
gimbal supported on pivots E, E, in the half gimbal B; F is the compass
bowl, which is suspended on pivots G, G, in the gimbal D. The compass
bowl is formed of glass, porcelain, earthenware, or other non-metallic material,
and has cemented or otherwise fastened to its upper edge a ring of brass H,
to which the pivots G, G, are attached. The compass bowl may also be formed
of
copper in the ordinary manner, but I prefer that it should be composed of
glass, or some non-metallic material, as above stated. I is the pedestal on
which the cap J, which sustains the compass card, is supported. The pedestal I
is fixed in the bowl by by being screwed into the socket K, which is cemented
into an aperture in the bottom of the bowl. The bowl is balanced by means
of the lead weight K¹. L is a cup of metal screwed on to the pedestal I; and
M is a ring which is screwed on to the cup L; N is a vulcanized india-
rubber disc, which is held between the parts L, M ; the edges of the disc
being furnished with washers of ivory or bone 0, 0, cemented thereto in order
to preserve the india-rubber from the corrosive action to which it would be
exposed by coming in contact with the metal of the parts L, M. In the
centre of the disc is an aperture in which is fitted the cap J, containing a
jewel for the steel centre P of the compass card to work in. Q is a flat ring
which screws on at the back of the cap, for the purpose of holding it in its
place in the disc N. R, R, are washers of ivory or bone, which are inter-
posed on both sides of the india-rubber disc between the shoulder of the
cap J and the flat ring Q, for the purpose of preserving the india-rubber, as
in the case of the washers O, O. By this arrangement the cap is not only
fixed elastically on the pedestal, but it is also completely insulated from it.
S is the compass card, which is constructed with two needles, placed parallel
to each other in the ordinary manner, as shewn by the dotted lines in
Figure 2; and T is the bridge of the card. U is a brass cylinder, screwed
into the bridge, in which is fitted the steel or other metal centre P which
supports the card, the extremities of the centre passing through small
apertures formed in the ends of the cylinder. The centre P has fixed to
it a metal disc V, which fits easily in the cylinder U; and two coiled springs
W, W, are placed, one above and the other below the disc, so as to bear
against it and the ends of the cylinder, by which means a spring bearing

page_text: is provided for the card on its centre. X is a glass cover to the compass
bowl. Figure 4 is a vertical section, and Figure 5 a plan, of a hanging or
cabin compass, with dipping needles, having part of my improvements
applied thereto. The same letters of reference used in describing Figures 1
and 2, indicate similar parts in these Figures.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that what I claim as of my
Invention is,
First, the employment of washers of bone or ivory in the adaptation of an
india-rubber disc spring to the cap of the compass, for the purpose of pre-
serving the india-rubber from the corrosive effect consequent on contact with
metal.
Second, the adaptation of a double action metallic spring, or its equivalent, to
the centre, on which the compass card is supported, so as to obtain a spring
bearing for the compass card.
And, third, the adaptation of metal springs, or their equivalent, to the pivots
and shoulders of the compass.
In witness whereof, I, the said Robert John Keen, have hereunto set
my hand and seal, this Twenty-fourth day of January, One thousand
eight hundred and fifty-five.