Improvements in Devices for Determining the Location of a Distant Object.
Year: 1894

page_text: Date of Application, 8th Sept., 1894-Accepted, 6th Apr., 1895
COMPLETE SPECIFICATION.
Improvements in Devices for Determining the Location of a
Distant Object.
I, BENJAMIN JOSEPH BARNARD MILLS of 23 Southampton Buildings in the
County of London, Patent Agent, do hereby declare the nature of this invention,
a communication to me from William C. Rafferty of Governor's Island, in
the County and State of New York in the United States of America, Lieutenant
in the United States Army, and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
This invention comprises mechanism for mechanically determining, from one
point by reference to a second point the location of which by polar co-ordinates is
known, the distance and azimuth of a third point relatively to said first point.
Thus, for illustration let one of the angles, A, of a triangle A B C represent the
first point, the base of said triangle being A B. By any suitable means the
distance and azimuth or the polar co-ordinates of C the third point relatively to B
the second point, is ascertained. 'At A is located the device contemplated in this
invention, and by its operation, based upon the calculation of distance and azimuth
of B to C, the point C is accurately determined relatively to A.
There are many connections in which the invention may be advantageously
employed. The particular embodiment illustrated in the drawings and hereinafter
described has, however, been designed for use in connection with gunnery or a
battery or batteries of guns. As will be readily understood, it is oftentimes
desirable to train a gun upon an object which is hidden from observation at the point
of location of the gun.
A range-finder at this point would, of course, be useless.
A location-determining device of any suitable kind may, however, be placed at a
third point where the view is uninterrupted and the distance and azimuth of the
object to be fired upon, relatively to that point, calculated and transmitted to the
gun or battery. By means of such calculation and the device of this invention
the gun or guns of the battery or batteries may then be trained upon the object
with great accuracy.
The invention is illustrated in the drawings in which
Figure 1 is a plan view of the invention;
Figure 2 is a section ou the line 2-2 of Figure
Figure 3 is a section on the line 3-3 of Figure 1;
;
Figure 4 is an enlarged detail view of a portion of the board and one of the arms
shown in Figure 1 ;
Figure 5 shows, in side and end elevation, a spacing piece by means of which the
position of the arms, relatively to each other, is regulated.
Figure 6 is a modification of said spacing piece ;
Figure 7 is a diagrammatic view hereinafter to be referred to; and
Figures 8 and 9 are enlarged detail views illustrating modifications of one of the
arms shown in Figure 1.
Referring to the drawings, in which similar letters of reference indicate corre-
sponding parts, A designates a flat base or board of metal or other suitable material
and approximately semi-circular as shown. In practice its periphery will measure
a little more than 180°. The upper surface of this board is finely divided into
parallel lines a in any suitable manner. For instance, the board may be divided
י

page_text: to the periphery thereof, is a circular graduation B, a portion of which, enlarged,
is shown in Figure 4. This graduation is so constructed and divided as to indicate
the degrees and parts of degrees relatively to the centre of the board. I have
herein shown a diagonal vernier for reading the angle to a small part of a degree.
By a numbering inside and outside of the vernier, the degrees are indicated
consecutively from 0 to 360°.
C designates a pivot secured to the centre of the board A. Upon this pivot is
mounted, by means of a sleeve e, one end of the radial arm D which extends across
the surface of the board A and projects a short distance beyond the periphery
thereof. At its free end the arm D is provided with a rearwardly extending
projection d through which may pass a screw d' of any suitable construction, the
office of which is to bind upon the periphery of the board A and thereby secure
the arm D in any position in which it may be placed.
The edge of the arm D is graduated as shown at D', Figures 1 and 4, the lines
of division being preferably accompanied by numerals increasing in proportion of
distance from the central point, which is the pivot C. At that point upon the arm
directly over the scale B, the arm D is provided with a further graduation D" see
Figure 4, designed to be used in connection with the divisions upon said circular
graduation. By this means a reading may be had to one minute of an arc or even
to less if desired.
E designates a radial arm similar in many respects to the arm D and mounted
upon the same pivot C. It is designed, by means of the construction described,
to so mount the arms that the movement of one will be entirely independent of
that of the other. The free end of the arm E may be provided with a clamping
device d' similar to that employed in connection with the arm D. The arm E is
also graduated upon its upper surface as at e'. The divisions of this graduation
may, like those of the arm D, be numbered in proportion to the distance from the
central point or pivot C and, also like said arm D, this graduation may be used for
the determination of distance. In the present embodiment of the invention,
however, in which the device is described in its application to the aiming of guns,
the graduation of the arm E will indicate the elevation necessary to be given to the
gun in directing the projectile towards a certain point.
F designates a spacing piece having a handle f. This piece may be made of
metal or other suitable material, and in practice its opposite edges are sharp as
shown in Figure 5.
The length of this spacing piece is determined by calculation, based upon the
graduation or scale of the arm D, of the distance between the gun in connection
with which the device is used and the point of location of the range-finder or
other apparatus by means of which the position of the object to be fired upon
is ascertained. In Figure 6 is illustrated at F¹ a modification of the spacing
piece F.
In this instance the body fl is provided with two downwardly projecting
needles adapted to be placed upon the board A in the same manner as that
in which the piece F is used.
Turning to the diagram illustrated in Figure 7, it will be seen that there are
several triangles having one side in common. This side is the line between the
point of location of the range-finder or other position-ascertaining device 2 and
the object 3 to be fired upon. The distance and azimuth of 3 from 2 may
be ascertained in any suitable manner. The distance and azimuth of the guns 1.
relatively to the point 2 will usually be unvarying and known. It will be
understood that the azimuth is generally measured from the "South" point around
to the "West."
The reading thus obtained at both points 2 and 1 is that given on the circular scale B
at the point where one of the parallel lines, passing through the pivot or centre C
of the board A, interrupts it. It now remains to determine from each of the
guns the position of the object 3 relatively thereto. A description of the opera-
tion of a single one of the several position-determining devices will be sufficient, it

page_text: being understood that one of the said devices is connected with each of the guns.
designated by a circle in this figure.
The location of the object 3 relatively to the range-finder 2 is transmitted to the
officer or other attendant at the gun. The arm D is then turned to a position upon
the board determined by the graduating media and representing the azimuth of the
object 3 as seen at 2. The spacing piece F is then placed upon the board A in or
parallel to one of the grooves a thereon or on or parallel to one of the lines marked
upon said board, one end of said piece F being placed against the edge of the arm D
opposite that mark of the scale thereon indicating the distance from the object 3 to
the range-finder 2. The arm E is then moved upon its centre until it touches the
other end of the spacing piece F. The reading of the circular vermer at the edge
of the arm E will then indicate the azimuth of the object 3 relatively to the gum 1,
and the reading of the scale on the arm E at the edge of the spacing piece F will
indicate the distance between the gun and said object 3.
As is well known, the direction of flight of a projectile is often influenced to a
considerable extent by the motion imparted to it through the "rifling" or grooving
of the gun from which it is impelled, as well as by the action of the wind, either
of which causes may operate to divert the projectile from a straight line between
the gun and the object fired upon.
I have provided for this contingency in the manner illustrated in Figures 8 and 9,
which show modifications of the arm E heretofore described. Referring first to
the former, it will be seen that the edge E³ of the arm E' is curved outwardly.
This curve will, of course, be very slight and will cause such a reading of the
circular vernier at the edge of the arm as will compensate for the deflection of the
projectile through any cause.
In Figure 9 is illustrated a construction by means of which the advantages of
both forms of the arm are combined. In this construction the arm is made in two
parts, one part E being similar to the arm E heretofore described, and the part E
being similar to the arm E2 above referred to. These two parts may be maintained
in proper position relatively to each other by any suitable means. I have,
however, shown for that purpose screws e mounted upon the part E' and
engaging with a stud or projection upon the part E³. Both of these parts may
be carried by the same sleeve, which is mounted upon the pivot C, or the
It will be under-
part E may be supported entirely by the screws e³ as shown.
stood that the curve of the edge of the arm E2 or that of the part E³ may be
varied in degree and that such curves, instead of extending outwardly, may
extend inwardly according as the varying conditions may necessitate a deviation
in the training of a gun.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what I
claim is :-
1. A device for determining the location of a distant point, comprising a base
having an azimuthal scale or graduation and pivotally mounted arms operating
upon said base, substantially as set forth.
2. A device for determining the location of a distant point, comprising a base
having an azimuthal scale or graduation, the surface of said base being provided
with parallel straight grooves or lines, pivotally mounted arms operating upon said
base and means adapted to be placed between said arms for limiting their movement
relatively to each other, substantially as set forth.
3. A device for determining the location of a distant point, comprising a base
having an azimuthal graduation, arms pivotally mounted upon said board and
having scales or graduations and a spacing piece adapted to be placed between said
arms, substantially as set forth.
4. A device for determining the location of a distant object, comprising a semi-
circular board having a diagonal graduation near its periphery, pivotally mounted
arms having graduations or scales and verniers for use in connection with said

page_text: diagonal graduation upon the board, and a spacing piece substantially as set
forth.
5. A device for determining the location of a distant point, comprising a board,
two arms mounted upon a pivot secured thereto and having scales or graduations
and a spacing piece having sharp edges and adapted to be placed between said
arms, to indicate the point upon the arms where a reading is to be taken,
substantially as set forth.
6. A base for use in connection with a device for determining the location
of a distant object, said base being provided with parallel divisions and having
a scale or graduation indicating the degrees of a circle, in azimuth substantially
as set forth.
7. A base for use in connection with a device for determining the location of a
distant object, said base having a diagonal scale or graduation numbered on both
sides and indicating the degrees of a circle in azimuth, substantially as set forth.
8. A base for use in connection with a device for determining the location of
a distant object, said base having a diagonal scale or graduation indicating the
degrees of a circle in azimuth and an arm operating in conjunction with said
board and having a vernier indicating the parts of a degree upon said scale or
graduation, substantially as set forth.
9. A device for determining the location of a distant object, comprising a base,
two arms mounted upon a common centre, a spacing piece for limiting the move-
ment of said arms toward each other and a parallel guide for said spacing piece,
substantially as set forth.
10. A device for determining the location of a distant object, comprising a base,
two arms pivotally mounted upon a common centre, means for clamping said arms
in any position upon said base, a spacing piece and means for guiding the same,
substantially as set forth.
11. A device for determining the location of a distant object, comprising a base,
two arms mounted thereon, one of which is provided with a curved edge, and a
spacing piece for limiting the movement of said arms toward each other,
substantially as set forth.
12. A device for determining the location of a distant object, comprising a base,
two arms mounted thereon, one of which is made in two parts, one of said parts
having a curved outer edge, substantially as set forth.
13. A device for determining the location of a distant object, comprising two
arms mounted upon a common pivot and representing two of the sides of a triangle,
the apex of which is the object, one of said arms having a scale or graduation
indicating the distance of the object relatively to a third point and the other
having a scale or graduation indicating the distance from the object to the device,
and a spacing piece representing the base of the triangle and determining the
movement of the latter arm toward the former, substantially as set forth.
Dated 8th September 1894.
Dated on September 1894.
B. J. B. MILLS,
By Harris & Mills,
23, Southampton Buildings, London, W.C., Agents.