Improvements in and relating to Apparatus for Finding the Range and Position of Distant Objects.
Year: 1890

page_text: Date of Application, 11th Nov., 1890-Accepted, 14th Feb., 1891
DAN DIMITIGATION.
Improvements in and relating to Apparatus for Finding the Range
and Position of Distant Objects.
1, BRADLEY ALLAN FISKE of No. 1 West 81st Street in the City, County and
State of New York, United States of America, Lieutenant in the United States
Navy, 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
5 following statement :-
The invention is a range and position finder and embodies first a pivoted alidade
arm or telescope moving over an are of conducting material, which arm is directed
upon the distant object; second, a pivoted pointer moving over a like are of
conducting material in a Wheatstone bridge circuit with said first-named arc; the
arrangement being such that when the alidade arm on the first arc, and the pointer
on the second arc stand at the same angle, the circuit is balanced. The pointer
arm moves over a suitable chart representing the area which includes the position of
the distant object on a reduced scale. On this chart there is a simple pivoted arm,
which may be an alidade arm or a telescope itself, and be trained directly upon the
object or said arm may be mechanically controlled by a telescope directed upon
the object so that it will make with the other arm an angle equal to that made by
the lines of sight drawn from the two telescopes to the object. The position of the
object is then shown by the intersection of the electrically directed pointer and the
mechanically directed arm upon the chart.
The invention further includes a construction of telescope and pointer arm
whereby said telescope controls said arm, and an apparatus for communicating
telephonically between the telescopes at distant stations so that the observers are
enabled constantly to transmit information as to the position of the target, direction
of line of sight, &c., to one another, without any interruption of their observation
of the target.
In the accompanying drawings,
Fig. 1 is a diagram showing the general disposition of my range and position
finder, and
Fig. 4 a similar diagram showing the chart D in different position.
Fig. 2 illustrates the preferred arrangement of telescope and pointer directed,
thereby;
Fig. 3 shows the construction of the pointer arms in detail.
Fig. 5 is a side elevation of one of the telescopes provided with a telephone
receiver and transmitter.
Figs. 6 and 7 are side views of said telescope and telephones combined and on a
arger scale.
Similar letters of reference indicate like parts.
appears
A. B represents, for example, the parapet of a fortification. The distant object
s supposed to be located at C; and it is the position of this object which is to be
etermined upon a suitable chart D, on which the fortification line A' B¹
na reduced scale. E is an arc of conducting material. F is a telescope or
lidade arm pivoted at one end at F with its free extremity moving over and
aking contact with the arc E. G is an arc similar in all respects to the arc E
nd located in suitable proximity to the chart D. H is an arm pivoted at H¹ and
aving its free end sweeping over and making contact with the arc G and carrying
pointer I. a, b, c, d, are members of a Wheatstone bridge connecting the arcs E
d G. e is a loop including the battery, and the loop including the galvano-
eter g. It will be obvious that when the arm H is set upon its arc G at the same
gle to the line H' F' as the arm F upon the arc E. then the bridge will helena
Fig. 4 a similar diagram showing the chart D in different position.
Fig. 2 illustrates the preferred arrangement of telescope and pointer directed,
thereby;
Fig. 3 shows the construction of the pointer arms in detail.
Fig. 5 is a side elevation of one of the telescopes provided with a telephone
receiver and transmitter.
Figs. 6 and 7 are side views of said telescope and telephones combined and on a
arger scale.
Similar letters of reference indicate like parts.
A. B represents, for example, the parapet of a fortification. The distant object
is supposed to be located at C; and it is the position of this object which is to be
determined upon a suitable chart D, on which the fortification line A' B' appears
on a reduced scale. E is an arc of conducting material. F is a telescope or
alidade arm pivoted at one end at F' with its free extremity moving over and
making contact with the arc E. G is an arc similar in all respects to the arc E
and located in suitable proximity to the chart D. H is an arm pivoted at H' and
having its free end sweeping over and making contact with the arc G and carrying
a pointer I. a, b, c, d, are members of a Wheatstone bridge connecting the arcs E
and G.
e is a loop including the battery, and the loop including the galvano-
meter J.
It will be obvious that when the arm H is set upon its arc G at the same
angle to the line H¹ F' as the arm F upon the arc E. then the bridge will balance-
TICE Xd

page_text: and the galvanometer will indicate zero; and hence inasmuch as the telescope F
points to the actual object C, so the arm H will point to the corresponding position
of the object C or C on the chart D. Pivoted upon the chart D at is an
arm J, which arm may be provided with a telescope or alidade, so that it may be
directed upon the object C. The arm J is long enough to make intersection with
the arm. If then the arm J is trained directly upon the object, inasmuch as the
line HJ joining the pivots of the arms I J on the chart D corresponds to the
base line FJ extending between the distant stations, and as the angle C¹ H¹ J¹
equals the angle C FJ, it follows that the intersection of the arms I and J at C¹
indicates the position of the object C upon the chart D. The chart being suitably
drawn to scale and laid off in divisions of known dimensions, it then becomes
easy to recognize at a glance both the bearing and distance of the object C from
any given point on the chart.
In actual practice and for purposes of convenience, I have adopted an
apparatus which is represented in Fig. 2. This consists of a tripod supporting
an upper platform K, which carries the standard L upon which is pivoted the
telescope M. Extending downward from the standard L and through the
platform K, is a shaft N which turns with the telescope and standard. The arm J
is carried by the shaft N and moves over a table also supported by the tripod on
the upper surface of which is marked the chart D. The arm J may be set parallel
to the telescope M; so that when the telescope M is directed upon the object, the
arm J will also be directed upon said object; although as hereinafter explained
this parallelism of arm and telescope is not essential. Carried upon the lower
table is also the arc G and arm H 1. The intersection of the arms I J over the
chart D, as already explained, shows the position of the distant object; and the
apparatus of Fig. 2 as indicated in Fig. 1, is to be located at one station, while
the arc E with its telescope F is to be located at any suitable distant station.
Referring now to Fig. 4, it will be seen that in this case the line II' J' on the
chart D, while corresponding as before to the base line F J' does not coincide with
that line, and hence that the arm J is itself not directed upon the object. This
represents the condition before referred to when the arm J is not set parallel to the
axis of the telescope M, but at an angle thereto, this angle being such that the
angle C JH will continue the same as the angle C J F' despite a change in
relative position of the chart D; such as indicated in Fig. 4.
In Fig. 3 is represented a construction of the intersecting arms or pointers I and J,
which is especially adapted for the uses before detailed, and which allows of the
actual intersecting point being determined with great accuracy. It will be obvious
that with a chart laid out on a small scale and using arms I J of sufficient width or
thickness to give them rigidity, the exact point of intersection of lines drawn
through the pivot centers of the arms, will be difficult to determine; and there may
be considerable error in regarding the apex of any one of the four angles made by
the intersecting arms as the true point indicated." In the device shown in Fig. 3,
this source of error is practically eliminated; and in addition other advantages
which I will detail hereafter, are secured.
The arm I has one edge K on a line passing through the pivot center H. On
the arm J is a slide M, which carries, projecting from the edge V of said arm, a
pointer N the extremity of said pointer being upon an imaginary line drawn
through the pivot center J¹ and indicated by the dotted line P Q. It will be
obvious that the point on the arm I indicated by the pointer N, will be the exact
point of intersection of lines drawn through the pivot points HJ. I propose to
graduate the arms I and J lineally to conform to the scale of the chart D; so that
the distance of the object from both separated stations, can at once be read. Thus,
on the arm I may be read the distance H¹ C¹ which is that of the object from the
station at which is located the telescope F, Fig. 1; and on the arm J may be read
the distance. C¹, which is the distance of the object from the station at which is
located the chart D. If it be desired to determine the distance of the object from
any intermediate station between the two mentioned, a third pointer R may be

page_text: placed in position between the two arms I J, and situated in the same relation
thereto as the intermediate station is to the two extreme stations. The distance
from the pivot point S of this arm to the point C', the place of intersection of the
edge of said arin with the point of contact of the edge K of arm 1, and the apex of
5 the pointer N, shows the distance of the object from the pivot point S, and hence
from the intermediate station. The slide M may be moved along by hand, and
may, if desired, be provided with any mechanical means for causing its motion. It
is provided with an opening T through which the scale marks on the arm J may
be read, and to allow this reading being made, there is a central mark U made on
the pointer N which comes into coincidence with any one of the scale marks.
It has been found in practice that observers at widely separated stations often fall
into the error of not turning their sight tubes or telescopes upon the same object.
Hence it will be readily seen that between the observers direct communication is
constantly necessary; in order that they may quickly agree as to the object or
point of the object, upon which they shall direct their telescopes. Frequent
changing of this point may be required by smoke or other accidental causes.
Inasmuch also as the target may be rapidly moving, it is necessary that means
should be provided not merely for continuous observation, but for the communication
of intelligence between the observers at any instant. If, in order to transmit such
intelligence or to receive it, an observer is obliged to remove his eye from the sight
tube, and to turn to some other instrument fixed in proximity thereto, his
observation will necessarily for the time being be interrupted, and still further
delay will follow in readjusting a new line of sight upon the target, which, in the
interval, may change position. The apparatus illustrated in Figs. 5, 6 and 7,
affords a convenient and efficient means of telephonic communication between the
servers at the two distant stations and enables them to see, hear and speak
multaneously. Its construction is as follows:-
A is the telescope or spy-glass supported in any suitable way on the table B"
nd having motion in azimuth on its pivot C" and motion in altitude on its pivot D".
Enclosing the tube of the telescope is a ring E" of any suitable light metal which
upports the telephone transmitter F at such distance below the telescope A" as
will bring the mouth-piece of the transmitter in convenient proximity to the mouth
of an observer looking through the eye-piece of said telescope.
The transmitter F is pivoted in any suitable way to the ring at G", so that the
mouth-piece may be adjusted laterally. Also supported upon the ring E" is a
flexible spring bar H". The bar H" is secured to the ring E" by a clamp nut 1"
upon a suitable pivot, on which pivot the bar may be turned, and the telephone
receiver J, which is supported on the end of said bar, thus slightly raised or
owered. On the back of the telephone receiver J" is its permanent magnet K",
which is provided with a longitudinal slot L which receives a clamping screw Mu
which passes through the bar H. On loosening the screw M", the position of the
elephone upon said bar may be adjusted. The transmitter and receiver are
rranged in circuit in any suitable way.
In operation the eye of the observer is placed at the eye-piece of the telescope A",
when his mouth then, as already stated, comes directly opposite the transmitter
upported on said telescope. The telephone receiver J then comes opposite to his
ar, and is held against the same by the elastic spring bar H". The observer then
as both hands free to manipulate the telescope, and in practice he uses one hand to
rn the instrument in azimuth and the other to elevate or depress it in altitude.
It will be apparent that under these conditions the observer is perfectly free to
aintain his line of sight through the instrument upon the object, and to both utter
d receive verbal communication with perfect ease; and this I find in actual
actice to be the case. The telephone receiver, transmitter and telescope become
actically one instrument susceptible of conjoint and simultaneous use; and
asmuch as the telephonic instruments are mechanically secured to the telescope,
ey necessarily follow every motion of that instrument, and always maintain their
lative position thereto. So that when an observer once accommodates himself to

page_text: the car-piece, mouth-piece and eye-tube, he need not change his position again with
reference to them, nor need he adjust them further in any wise.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The construction and arrangement of a range and position finder embodying
a chart representing the area including the object on a reduced scale, pointers on
said chart and a sight-tube or an alidade at a distant station, and electrical connections,
substantially as hereinbefore described.
2. The combination of a telephone and telescope substantially as herein before
described.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.