Improvements in the Mariner's Compass.
Year: 1890

page_text: Date of Application, 10th June, 1890
Complete Specification Left, 10th Mar., 1891-Accepted, 18th Apr., 1891
PROVISIONAL SPECIFICATION.
Improvements in the Mariner's Compass.
I, Sir WILLIAM THOMSON, Professor of Natural Philosophy, in the
University of Glasgow, in the County of Lanark, North Britain, do hereby
declare the nature of this invention to be as follows:-
The improvements which form the subject-matter of this invention are designed
to prevent the inconvenience and damage to the compass which are caused by
excessive vibration on board ship from the engines or from the firing of heavy
guns. The vibration from the engines and firing of heavy guns have a tendency
to set the compass oscillating, and the concussion which is caused by the firing of
the guns is liable to break the glass of the compass bowl when the azimuth
instrument is supported directly on the glass.
The invention consists of two parts:-1st. An improved elastic suspension for
supporting the compass bowl; 2nd. An improved method of carrying the azimuth
instrument on the verge of the compass bowl.
In carrying out the first part of my invention I provide two tubes, one on the
fore part of the binnacle, and the other on the after part. At the bottom of each
of these tubes there is a spiral spring which supports a weighted tube properly
guided so as to be capable of movement up and down in a vertical direction. At
the top of these weighted tubes, hangers are provided which carry the gimbal
ring of the compass bowl in such a manner as to give it freedom for a considerable
extent of horizontal movement.
In carrying out the second part of my invention, a channel is formed in the
verge of the compass bowl, in which the azimuth instrument, resting on three feet,
is placed, and in which it can be turned by means of a handle provided at the
centre of the instrument.
D
1
CT 1200
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Agents.
COMPLETE SPECIFICATION.
Improvements in the Mariner's Compass.
I, Sir WILLIAM THOMSON, Professor of Natural Philosophy, in the
University of Glasgow, North Britain, 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 :-
The improvements which form the subject matter of this invention are designed
to prevent the inconvenience and damage to the compass which are caused by
excessive vibration on board ship from the engines or from the firing of heavy
guns. The vibration from the engines and firing of heavy guns have a tendency
to set the compass oscillating, and the concussion which is caused by the firing of
the guns is liable to break the glass of the compass-bowl when the azimuth
instrument is supported directly on the glass.
The invention consists of two parts: 1st. An improved elastic suspension for
supporting the compass-bowl; 2nd. An improved method of carrying the azimuth
instrument on the verge of the compass bowl.
In carrying out the first part of my invention I provide two tubes, one on the
fore part of the binnacle, and the other on the after part. At the bottom of each
of these tubes there is a spring which supports a weighted tube properly guided so

page_text: At the top of
as to be capable of movement up and down in a vertical direction.
these weighted tubes, changers are provided which carry the gimbal ring of the
compass-bowl in such a manner as to give it freedom for a considerable extent of
horizontal movement.
In carrying out the second part of my invention, a channel is formed on the
verge of the compass-bowl, in which the azimuth instrument, resting on three feet,
is placed, and in which it can be turned by means of a handle provided at the
centre of the instrument.
In order that my invention may be properly understood and readily carried into
effect, I have hereunto appended two explanatory sheets of drawings, in the
several figures of which corresponding parts are marked with the same letters of
reference.
Figure 1 is a section through the fore and aft centre line of the binnacle.
Figure 2 is a detached view of one of the hangers.
Figure 3 is a modification of the upper part of the weighted tubes.
Figure 4 is a modification of the weighted tube and elastic support in which flat
springs are substituted for the spiral springs of Figure 1. It is partly a thwart-
ship section and partly an elevation.
Figure 6 is a section of the verge of the compass-bowl with the lower part of
the azimuth instrument; and Figure 5 is a plan of the same.
The two tubes A A. are let into the woodwork of the binnacle, and have a spiral
spring B inside each of them. A smaller brass tube C, filled with lead, forming a
heavy plunger, rests on the spiral spring B in each tube. Attached to the loaded
tubes C, near the top there are a number of flat bent metal springs c, which form a
springy guide for the heavy plunger. A bent piece of metal c¹ projects beyond the
top of each heavy plunger and forms a bracket from which the compass-bowl is
hung by the hangers D, D, as shown in the drawing. The brackets have each
a conical hole in which a half sphere d on the hanger rests. This ball-and-socket
arrangement gives freedom for horizontal motion to the bowl, while the spiral
spring which supports the plunger carrying the compass-bowl allows of vertical
motion. An enlarged view of one hanger is shown at Figure 2. The V-shaped
bearing in which the knife-edge journal of the gimbal ring rests is pivoted, and
free to turn round an axis d d. Guards E, E, Figure 1, on the gimbal ring
prevent the journals from coming out of the V's.
In some cases it may be desirable to augment the action of the spring by
making the bracket springy. This is illustrated in Figure 3 in which the bracket
is made up of several pieces of springy metal laid close to one another and all
fastened together at the top of the plunger.
Other forms of spring may be substituted for the spiral spring. For example in
Figure 4 I have shown a series of bent pieces of metal b, built up to form a suitable
springy support for the plunger. These may be made of rectangular shaped
pieces of metal, and may be placed in a suitable receptacle formed in the binnacle
with the plunger resting upon them. The plunger may be made of rectangular
section and have a suitable chamber c² formed at the bottom, in which the springs
can be placed, as shown at Figure 4. The plunger is supported by the springs
resting on a solid piece of brass or wood attached to the woodwork of the
binnacle. The bottom of the chamber has a lip c formed on it, which prevents
the springs coming out, but allows the plunger C to rise and fall freely.
The method of hanging the compass bowl is similar to that already described.
For carrying the azimuth instrument of the compass I form in the verge of the
bowl a channel g, Figures 5 and 6, in which the azimuth instrument, resting on
three feet is supported without touching the glass of the compass-bowl. An opening
is formed in the cover of the channel to allow of the azimuth instrument being put
in position. The inner edge of the upper lip g' of the channel forms a guide by
which three upright pieces h', h2, h3, formed on the sole of the azimuth instrument,
keep it in position, but allow it freedom to be turned without friction by means of
the handle H.

page_text: 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:-
1. The elastic support for the compass-bowl consisting of the loaded plunger
supported on springs having a bracket which may be either stiff or springy, from
which the compass-bowl is hung by hangers, substantially as described.
2. The method of supporting and guiding the azimuth on the brass rim of the
compass-bowl, and the handle provided for turning it, substantially as described.
Dated this 9th day of March 1891.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Agents.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Agents.