Year: 1897

page_text: I, THOMAS GERALD FITZ-GIBBON MC.COMBIE, Laurel Bank, Monkstown
Avenue, Monkstown, County Dublin, Ireland, Commander Irish Lights Steamer
"Tearaght," do hereby declare the nature of this invention to be as follows:-
-
This invention has reference to instruments for finding positions of ships and
other bodies by taking angles, and then transmitting them directly by the instru-
ment to a chart or plan, whereby the position taken is fixed thereon; the instru-
ment, however, being also applicable for taking or measuring angles from charts,
and by the aid of it, placing buoys or vessels in the required position out at sea.
The object of the present invention is chiefly to provide improvements, hereinafter
described, in connection with this kind or type of instrument.
An instrument according to this invention has three legs, and a circle divided
into degrees and sub-divisions, one of the legs being fixed to the circle, and the
others movable. The moving legs are hinged at the centre of the circle. In
connection with these parts, there is combined and used horizon and index mirrors,
by means of which the objects can be brought into the instrument, or taken, and
the angle set. The main parts of the instrument, as stated, comprise the fixed,
i.e. the central, leg, having at its inner end attached to it the circle referred to;
while, on either side of it, are the hinged legs, the axes of which are coincident
with centre of the circle; then in connection with these parts, there are hinged
bars, the hinges of which are in line with the centre of the fixed leg, the other
parts or ends working in connection with fixed points on the two side hinged legs,
and on each of these bars an index or sight glass is placed. The horizon mirror
or glass is placed near the outer end of the central fixed limb, and the index
mirrors are placed on the index bar closely together near the axes or hinges of
them, i.e. near the centre line of the central leg. These index bars are so arranged,
that as the movable legs are moved away from the central fixed leg, the bars
carrying the index mirrors are also moved about their hinges, and so move or alter
the angle of these mirrors.
The horizon mirror is so placed on the central or fixed leg that its surface runs
at right angles to the centre line thereof, and perpendicular to the frame; whilst
the surfaces of the index mirrors are also perpendicular to the plane of the instru-
ment, and in one case-parallel with the centres of the slots in the cross bars
on which they are mounted; or, according to a modified arrangement, at right
angles thereto. In use, the hinged arms are moved out, until the objects it is
required to sight, are brought into the index and horizon mirrors or glasses in the
required manner; and when this is done, and the legs fixed, the angles can be
read off from the circle, and the position on a chart found. By this means
instruments of this kind (generally known as station pointers) are rendered capable
of measuring angles between visible objects.
According to one special form of instrument under this invention, the central
leg has secured to it at one end, the circle, from which part the divisions are

page_text: marked off on either side; and also, in some cases, the points of the compass, the
centre line being "North" and "South." In this leg there is a slot running
down it, for nearly the whole length; the edges of the slot being bevelled. Hinged to
and springing from the same centre of the circle are the two movable legs, the inner
edges of which are in a line with the centre of the circle; and these edges are bevelled.
The joint at the centre of the circle forming the hinge of the legs, is tubular, with
a half-plate attached to the bottom, the edge of which is bevelled, and is provided
with a centre notch, representing the centre point of the instrument.
In the arrangement being described, the index mirror bars are hinged on the
same centre, at a point in the centre line of the main or stationary leg, and they
are slotted centrally and work over a pin on the movable side legs, the centre of
which pin lies in the line of the internal edge of the legs, and at a distance from
the circle centre, equal to that of the hinge pin of such bars from such centre.
These two side leg pins, and the slot in which the leg pins work, are all in line,
and the side legs are adapted to be clamped to the index mirror bars; this being
effected in a convenient arrangement, by a clamping bolt and nut passing through
the slot, and a link extending from said pins to a point outside the legs. The
index glasses, in this case, are mounted closely together at the hinge pin of the
index bars, they being parallel with the slots in them; and they are, in some cases,
so fitted in their frames, that they can be moved by screws, to adjust them into
their correct and desired positions.
As stated, the notch in the centre of the circle tubular pin will be its centre
point; and, on the leg, verniers are fitted, which work in conjunction with the
graduated scale, and which give the exact reading to the angles taken. Also in
connection with the circle, a magnifying glass is in some cases employed, it being
carried by a revolving arm from the tubular centre pin, and by it the angles or
divisions on the graduated circle, and verniers, can be easily read.
In connection with the circle, there is fitted a removable sight tube and telescope,
the end of which is adapted to fit into the tubular pin at the centre of the circle,
and by which the objects can be sighted and seen.
In some cases, the legs of the instrument are adapted to be lengthened, and are
provided with provisions by which, by screws, catches, or the like, special lengthen-
ing pieces can be applied, and fastened onto the ends of the permanent ones.
Dated this 12th day of April 1897.
CHEESBROUGH & ROYSTON,
Applicant's Patent Agents, 15, Water Street, Liverpool.
66
Improvements in Angle and Position Finders.
I, THOMAS GERALD FITZ-GIBBON MC.COMBIE, of Laurel Bank, Monkstown
Avenue, Monkstown, County Dublin, Ireland, Commander Irish Lights Steamer
Tearaght," 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 has reference to instruments for finding positions of ships and
other bodies by taking angles, and then transmitting them directly by the instru-
ment to a chart or plan, whereby the position taken is fixed thereon; the instru-
ment. however, being also applicable for taking or measuring angles from charts,
and by the aid of it, placing buoys or vessels in the required position out at sea,
and for similar objects.

page_text: The object of the present invention is chiefly to provide improvements, hereinafter
described, in connection with this kind or type of instrument.
An instrument, according to this invention, has three legs, and a circle divided
into degrees and sub-divisions, one of the legs being fixed to the circle, and the
others movable. The moving legs are hinged at the centre of the circle. In
connection with these parts, there is combined and used horizon and index mirrors,
by means of which the objects can be brought into the instrument, or taken, and
the angle set. The main parts of the instrument, as stated, comprise the fixed,
i.e. the central, leg, having at its inner end attached to it the circle referred to;
while, on either side of it, are the hinged legs, the axes of which are coincident
with the centre of the circle; then, in connection with these parts, there are hinged
bars, the hinges of which are in line with the centre of the fixed leg, the other
parts or ends working in connection with fixed points on the two side hinged legs,
and on each of these bars an index or sight glass is placed. The horizon mirror
or glass is placed near the outer end of the central fixed limb, and the index
mirrors are placed on the index bar closely together, near the axes or hinges of
them, i.e. near the centre line of the central leg. These index bars are so arranged,
that as the movable legs are moved away from the central fixed leg, the bars
carrying the index mirrors are also moved about their hinges, and so move or alter
the angle of these mirrors.
The horizon mirror is so placed on the central or fixed leg that its surface runs
at right angles to the centre line thereof, and perpendicular to the frame; whilst
the surfaces of the index mirrors are also perpendicular to the plane of the instru-
ment, and in one case-parallel with the centres of the slots in the cross bars
on which they are mounted; or, according to a modified arrangement, at right
angles thereto. In use, the hinged arms are moved out, until the objects it is
required to sight are brought into the index and horizon mirrors or glasses in the
required manner; and when this is done, and the legs fixed, the angles can be
read off from the circle on the instrument placed on the chart, and the position
on a chart found. By this means, instruments of this kind (generally known as
station pointers) are rendered capable of measuring angles between visible objects.
According to one special form of instrument under this invention, the central
leg has secured to it at one end, the circle, from which part the divisions are
marked off on either side; and also, in some cases, the points of the compass, the
centre line between "North" and "South." In this leg there is a slot running
down it, for nearly the whole length. Hinged to and springing from the same
centre of the circle are the two movable legs, the inner edges of which are in a line
with the centre of the circle. The joint at the centre of the circle forming the
hinge of the legs, is tubular, with a half-plate attached to the bottom, the edge of
which is bevelled, and is provided with a centre notch, representing the centre
point of the instrument.
In the arrangement being described. the index mirror bars are hinged on the
same centre, at a point in the centre line of the main or stationary leg, and they
are slotted centrally, and work over a pin on the movable side legs, the centre of
which pin lies in the line of the internal edge of the legs, and at a distance from
the circle centre, equal to that of the hinge pin of such bars from such centre.
These two side leg pins, and the slot in which the leg pins work, are all in line,
and the side legs are adapted to be clamped to the index mirror bars; this being
effected, in a convenient arrangement, by a clamping bolt or screw passing through
the slot, and a link extending from said pins to a point outside the legs. The
index glasses, in this case, are mounted closely together at the hinge pin of the
index bars, they being parallel with the slots in them; and they are, in some cases,
so fitted in their frames, that they can be moved by screws, to adjust them into
their correct and desired positions.
As stated, the notch in the centre of the circle tubular pin will be its centre
point; and, on the leg, verniers are fitted, which work in conjunction with the
graduated scale, and which give the exact reading of the angles taken. Also, in

page_text: connection with the circle, a magnifying glass is in some cases employed, it being
carried by a revolving arm from the tubular centre pin, and by it, the angles or
divisions on the graduated circle, and verniers, can be easily read.
In connection with the circle, there is fitted a removable sight tube and telescope,
the end of which is adapted to fit into the tubular pin at the centre of the circle,
and by which the objects can be sighted and seen.
In some cases, the legs of the instrument are adapted to be lengthened, and are
provided with provisions by which, by screws, catches, or the like, special lengthen-
ing pieces can be applied, and fastened onto the ends of the permanent ones.
In the drawings hereto annexed, two modifications under the invention are
illustrated, the views, Figures 1, 1^ and 1, and Figures 2, 24, and 2", being plans
and details of the two modifications.
Referring, in the first instance, to the modification shewn in Figure 1, a and b re-
present the three legs of the instrument, and c is the circle connected with them.
Of these legs, a is a fixed one, that is, it is fixed to the circle c; and b are movable,
being hinged to the centre c¹ of the circle c, about which they are free to move,
with their inner faces exactly in line with the centre of the circle.
The index bars are designated d, and are hinged on the centre line of the leg a.
These index bars have a slot d along them; and a slide e fixed on the end of
a pin b¹, on the legs b, fits in, and is adapted to slide along the slots d'; while the
legs b and bars d, are respectively supported from the circle, and controlled and
guided by the circle c, through a guide block e, fixed on the legs, and sliding in
and over the slot e, in c; the block e having a clamping screw e¹, by which the
bars are locked and unlocked with b.
The fixed central leg a has upon its end, the stationary "horizon" glass f; and
the two bars & have at their inner ends, over the point g, about which they vibrate,
"index" glasses h with reflecting faces on the sides opposite the glass f, the
reflecting face of f, of course, facing the circle. The centre of the fixed leg a
has a narrow slot a¹ down the whole of its centre, for the purpose of seeing the
main point, or base, from which the position is to be found, when placing the
instrument on the chart directly under the centre of the instrument, for the purpose
of finding a position.
The glass of the leg a is provided with a clear horizontal part f¹ in the centre,
as shewn in detail in Figure 14, by which the first and base point, from which the
position is to be found, can be seen through the glass; and, down this glass, a
vertical line may be provided. The two index glasses are disposed on their
respective arms, one above the other, as shewn in detail in Figure 1", and with a
space between them, in the same horizontal plane as the clear space in the horizon
glass f, so that a clear line of vision is provided across the centre of the circle,
and through the clear space f¹. The two glasses h, will be in the same horizontal
plane as the upper and lower silvered or reflector parts of the glass f.
The axes about which the mirrors h move, are coincident; and they are also
coincident with the point g about which the bars d move.
In the centre of the circle c, which, as stated, is of hollow or tubular form, and
forms a hinge to the movable legs b, there is a central half plate i, with a notch in
it, which will be the exact centre of the circle, and the point about which the legs b
move round the circle.
In use, to find, say, the position of a vessel upon the chart, a sight is taken across
the centre of the circle, and through the centre of the clear space fl of the glass f:
and the base object from which the angle is to be found, is brought into this line
of sight. Then the thumb screw e¹ connected with one of the legs b is unclamped
to enable that leg to be moved; and this leg is moved until another stationary
obiect or point, is brought into the index mirror h connected with that arm, and
reflected into the reflector of the horizon glass f. When these two objects are
coincident in f, the clamping screw referred to is screwed up, and the angle between
the two objects, and the ship, becomes determined. Then the clamping screw of
the ther leg is loosened, and the third object is brought into the index glass

page_text: connected with it, and reflected onto the horizon glass f, until it will be in line
with the main point, when it is fixed; and then all three points will be in line
with each other, the primary object being visible in the centre, and the two
secondary objects above and below, reflected in to the horizon glass. If, now, the
instrument be placed on the chart, so that the central point can be seen through the
slot of the fixed leg a, and the inside edges of the other two legs be made to
coincide with the points with which they have been respectively employed, for
ascertaining and fixing the angles, the exact position of the vessel on the chart will
be that directly under the centre of the circle; and this centre being hollow, as
shewn, by means of the notch in the plate i, this position can be marked off on
the chart by a pencil or other marking instrument.
The circle c may be graduated, and provided with a vernier, or not, as may be
desired, according to whether the angles taken are to be ascertained and measured,
or not; and a small telescope may be employed on the centre of the circle to take
the observations.
Referring now to the modification shewn in Figures 2, 2^, and 2", it is a modi-
fication in which the arrangement of the index glasses or mirrors, referred to, are
at right angles to the index bars on which they are mounted, in lieu of being
parallel, as in the instrument shewn in Figure 1; but in the case shewn, only one
index bar and mirror so arranged is employed, it being adapted to operate
alternately in connection with one or other of the two legs, at will. The legs b
and a, in this case, are hinged and fixed, respectively, on the circle c, as in the
former construction, and the moving legs are made fast to it, by means of the
slides e and clamping screws e¹, and pins b¹. The circle c is slotted, as shewn,
and the pins b¹, and the shanks of the clamping screws e¹ pass through the slots;
and, further, in this case, the pins ¹ project up above the surface of the slide e,
and serve to make the connection between the slides and index bars d.
To make this connection, the bar d, in itself, is more or less flexible or elastic,
constituting a spring bar, it being held down to the circle c by a hinge or similar
joint, coincident with the centre of the glass h, and about which centre or joint it is
free to rock; and at the free end is provided with a slot d', practically of the same
size as the pins b'. The index glass h itself is on the back end d² of the bar d,
and with its face or reflecting surface at right angles to the direction of length of
the base bar; and it is provided at the centre with a clear space at h³, constituting
a sight window, through which observations along the centre of the instrument,
and through the horizon glass, can be taken; the rest of the glass being a reflector.
The glass f, in this instrument, is shewn placed comparatively close to the circle c;
and it is half reflector, and half plain, so that distant sights can be taken
through it.
In the drawings, it is shewn secured to the centre leg a, but, if desired, it could
be supported upon a part of the circle c, which would project out from the edge, in
the direction of the central leg.
In action, the spring index bar d having been sprung over a pin 6' of one of the
legs b, and a sight taken of the first object through the window of the glass h
and the plain portion of the glass f, the moving leg so coupled up to the bar d, is
moved about until, by the glass h, the secondary object is reflected into the horizon
glass f; and when on the vertical centre line of that glass, and in line with the
primary object, the clamping screw el connected with that leg is screwed down, and
the angle so fixed. Then, the bar d is sprung off the pin 61 of this leg, and
sprung over the pin b¹ of the other leg; and in a like manner, this leg is operated
and the third object brought into the horizon glass f, and fixed. Then with these
angles fixed, the exact position of the ship on the chart can be ascertained in
the manner above referred to.
In either of the instruments shewn and described, a handle can be fitted to them,
for holding them.
As a further modification, if the legs a and b be graduated to a suitable scale, it
may be used for the purpose of distance or range finding.

page_text: In the drawings, two complete apparatus are shewn, but it is to be stated that
the invention is not restricted to them, as it is susceptible of various modifications.
As instances, in the arrangement shewn in Figure 1, the circle could be dispensed
with, and the legs and index bars, with their reflectors, alone used. Then, again,
in the case of the apparatus shewn in Figure 2, the circle with the index arm and
glass, and the horizon glass fixed upon it, could be used without the legs, and
employed as an angle finder, the circle being suitably graduated. And besides
these, the invention comprises other novel characteristics, which are specified in
the claiming clauses concluding the specification.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. The improvement in instruments of the kind herein referred to, namely, an
instrument having stationary and movable legs, a stationary horizon glass, con-
nected with the stationary leg, and movable glasses, on or connected with and
moved by the movable legs, and by which objects are reflected or brought into the
horizon glass; for the purposes set forth.
2. An instrument of the kind herein referred to, comprising movable legs, and a
stationary leg, a stationary horizon glass connected with said legs, a bar or bars
connected by a movable joint and disposed on the centre line of the instrument, and
connected with and operated by the movable legs, and carrying or moving a
reflector or reflectors, by which objects are brought into the stationary horizon
glass, and a circle connected with same, the centre of which is the point about
which the movable legs move; substantially as and for the purposes set forth.
3. An instrument for the purposes described, comprising a stationary leg a,
movable legs b, fixed glass 7, ring c, arms d, and reflectors h; arranged and
adapted to operate substantially as set forth with reference to the drawings.
4. In an instrument of the kind herein referred to, a circle having connected
with it a fixed glass, and a movable glass or glasses supported upon and moved by a
bar or bars, operated by a moving device having circular movement about the
centre of the circle, and at a distance from the circle, equal to the distance of the
vertical centre of said moving glass or glasses from the centre of the circle;
substantially as set forth.
5. An instrument of the kind herein referred to, having a stationary leg a,
movable legs b, fixed glass f, circle c, and a detachable or changeable bar carrying
a glass, and adapted to engage with and be disengaged from the said moving legs;
substantially as set forth.
6. In an instrument of the kind herein referred to, a circle c, with detachable
alternating bar d, and glass h; arranged and adapted to operate substantially as
and for the purposes set forth.
7. The construction, and arrangement of parts, as set forth with reference to and
shewn in Figures 1, 1, and 1", 2, 24, and 2, of the drawings, for the purposes
specified.