An Improved Form of Station Pointers.
Year: 1894

page_text: Date of Application. 15th Oct., 1894
Complete Specification Left, 15th June, 1895-Accepted. 20th July, 1895
PROVISIONAL SPECIFICATION.
An Improved Form of Station Pointers.
I JOHN FRANCIS STUART of H.M.S. "Hawke” in the Mediterranean Fleet.
a Lieutenant in the Royal Navy do hereby declare the nature of this invention
to be as follows:-
My invention which is shown in the accompanying drawings consists of a circular
sheet A. of zylonite or other transparent substance graduated at its edge in degrees
to the right and left from a radial line M N up to 180 degrees each way.
Through the centre of this sheet a circular hole is made and through this hole a
flanged metal pivot B of the same external diameter as the hole is passed upwards,
the flange at its lower end preventing it from passing completely through. The
pivot is made hollow and has a small hole in the centre of the bottom of it to allow
the point of a lead pencil to pass through.
Over the pivot is placed a circular sheet C. of the same material as, and smaller
than, the sheet A. so as to be concentric with the sheet A.
The sheet C. is graduated at its edge in degrees.
A metal arm D having a circular hole at one end which exactly fits the pivot is
dropped over the pivot B.
This arm D has one of its edges bevilled and made so as to be coincident with a
radial line from the centre of the hole at its end.
The arm D is rivetted on to the circular sheet C. with its bevilled edge along
the radial line M E joining the centre of the sheet with the zero mark of its
graduation.
The arm D is sufficiently long to overreach the edge of the sheet A.
A strip of metal F is rivetted to the arm D. underneath it so as to form a
continuation of the arm and having one edge P P bevilled and in a right line with
the bevilled edge of the arm D.
The inner end of the strip F extends under the sheet A. and a threaded pin G
is fixed vertically to the strip F between the rivets R and the outer edge of the
sheet A. and passes through a hole in the arm D.
By means of a milled nut H travelling on the pin G the arm D may be clamped
to the sheet A. with its bevilled edge at any degree of the arc.
The arms I and J, in every way similar to the arm D, except that they have no
sheet such as C. attached to them, and that the bevilled edge of the arm I. faces
the bevilled edge of the arm D. are placed over the pivot B.
A milled nut K is screwed over the threaded top of the pivot so as to hold down
the arms in their places but at the same time allowing them to revolve freely
around this pivot.
A metal arm L is rivetted on underneath the sheet A. with its bevilled edge
coinciding with the radial line M N.
The arms I and D may thus be clamped to the sheet A. at any desired angle
from its radial line M N, and as the graduated sheet C. revolves with the arm D.
the arm J. may be set at any desired angle from the arm D. and clamped in this
position to the sheet A.
Lengthening pieces Q may be attached to each arm.
The instrument may therefore be used as the ordinary station pointers now in
general use for fixing the position of a point on a chart by two angles, and in

page_text: addition a third or check angle may be made use of by means of the arm J.
simultaneously and without any calculation.
The advantages I claim for this instrument are that, in addition to its being used
as ordinary station pointers, a third or check angle may be made use of simul-
taneously and without any calculation; also that by its construction no part of the
instrument except the arms, obscures the chart and consequently it can be used in
many cases where ordinary station pointers cannot.
Dated this 15th day of October 1894.
W. J. WIGSTON,
Agent for Lieut. John Francis Stuart, R.N.
An improved Form of Station Pointers.
I JOHN FRANCIS STUART of H.M.S. "Hawke" in the Mediterranean Fleet
a Lieutenant in the Royal Navy do hereby declare the nature of this invention
and in what mauner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
My invention which is shown in the drawings left with the Provisional
Specification consists of a circular sheet A of zylonite or other transparent
substance graduated at its edge in degrees to the right and left from a radial
line M N up to 180 degrees each way.
Through the centre of this sheet a circular hole is made and through this hole a
flanged metal pivot B of the same external diameter as the hole is passed upwards,
the flange at its lower end preventing it from passing completely through. The
pivot is made hollow and has a small hole in the centre of the bottom of it to
allow the point of a lead pencil to pass through.
Over the pivot is placed a circular sheet C. of the same material as and smaller
than the sheet A. so as to be concentric with the sheet A.
The sheet C is graduated at its edge in degrees A metal arm D having a
circular hole at one end which exactly fits the pivot is dropped over the pivot B.
This arm D has one of its edges bevilled and made so as to be co incident with a
radial line from the centre of the hole at its end.
The arm D is rivetted on to the circular sheet C. with its bevilled edge along
the radial line M E joining the centre of the sheet with the zero mark of its
graduation.
The arm D is sufficiently long to over-reach the edge of the sheet A.
A strip of metal F is rivetted to the arm D underneath it so as to form a
continuation of the arm and having one edge P. P. bevilled and in a right line
with the bevilled edge of the arm D.
The inner end of the strip F extends under the sheet A and a threaded pin G is
fixed vertically to the strip F between the rivets R and the outer edge of the
sheet A and passes through a hole in the arm D.
By means of a milled nut H travelling on the pin G. the arm D may be clamped
to the sheet A with its bevilled edge at any degree of the are.
The arms I. & J. in every way similar to the arm D except that they have no
sheet such as C. attached to them, and that the bevilled edge of the arm I. faces
the bevilled edge of the arm D, are placed over the pivot B.
A milled nut K is screwed over the threaded top of the pivot so as to hold
down the arms in their places, but at the same time allowing them to revolve freely
around this pivot.
A metal arm L is rivetted on underneath the sheet A with its bevilled edge
co-inciding with the radial line M. N.
The arms I and D may thus be clamped to the sheet A at any desired angle

page_text: from its radial line M. N. and as the graduated sheet C revolves with the arm D
the arm J may be set at any desired augle from the arm D and clamped in this
position to the sheet A.
The instrument may
Lengthening pieces Q may be attached to each arm.
therefore be used as the ordinary station pointers now in general use for fixing the
position of a point on a chart by two angles, and in addition a third or check angle
may be made use of by means of the arm J. simultaneously and without any
calculation.
The advantages I claim for this instrument are that in addition to its being
used as ordinary station pointers a third or check angle may be made use of
simultaneously and without any calculation.
Also that by its construction no part of the instrument except the arms obscures
the chart and consequently it can be used in many cases where ordinary station
pointers cannot.
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
The replacement of the metal frame of ordinary station pointers by a transparent
substance and the attachment of a transparent movable scale of degrees to one of
the arms.
W. J. WIGSTON,
Agent for Lieut. John Francis Stuart, R.N.