Improvements in Apparatus for Finding the Range or Position of Distant Objects.
Year: 1893

page_text: Date of Application, 1st Feb., 1893-Accepted, 12th Aug., 1893
COMPLETE SPECIFICATION.
[Communicated from abroad by THE AMERICAN. RANGE FINDER COMPANY,
a corporation organized under the laws of West Virginia, and having its place
of business at corner of Greenwich and Thames Streets, New York, United
States of America.]
Improvements in Apparatus for Finding the Range or Position of
Distant Objects.
I, HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co. Patent Agents,
45 Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of this invention and in what mannor the same is to be performed, to be
particularly described and ascertained in and by the following statement :—
The invention consists in an apparatus for determining the distance of an object
and its bearing with reference to a certain locality. It is intended for use more
particularly as a position finder, to be employed on shore, as, for example, in a
fortified place at the entrance of a harbor. It enables the position of a ship or
other object afloat to be accurately determined, and thus renders it possible to train
a gun or a battery of guns upon such object so that the projectile or projectiles
will strike the same. The apparatus consists in two principal parts; namely, a
device for determining the distanco and a device for determining the direction or
bearing of the object. The said two parts are used conjointly, and thereby the
location of the object may be recognized upon a chart representing the area of the
harbor, for example, drawn on a reduced scale.
In the accompanying drawings,
Fig. 1 is a diagram illustrating the operation of the distance or range finder.
Fig. 2 is a diagram illustrating the operation both of the range finder and of
that part of the apparatus which shows the bearing of the distant object.
Fig. 8 is a side elevation of the observer's instrument and shows the mechanism
theroof on a larger scale and in detail.
Fig. 3 is an enlarged detail view of part of Fig. 3 drawn to an enlarged scale.
Similar letters of reference indicate like parts.
Referring first to Fig. 1, A is a telescope, sight-bar, or other like means of
directing the line of sight, indicated by the dotted line, upon the object B. This
telescope is to be located upon an elevation adjacent to the waterway to be
protected. The telescope is pivoted at its outer end, so that it can be depressed
through any desired angle in order to bring it to bear upon the object. The
telescope is provided near its sight end with a contact piece or wiper which always
bears upon a body of conducting material, represented symbolically at C, Fig. 1.
Connected with the ends of the body C is a voltaio battery, D, and connected in
circuit with one end, E, of the, body C and with the movable wiper or contact
piece carried by the telescope A, is a galvanometer, F. It will be apparent that
as the telescope A is moved on its pivot, its contact piece or wiper will be carried
along the body C; and, as a consequence, a greater or less amount of the body C
will be brought into the circuit which includes the galvanometer F. Inasmuch as
the body C is to be constructed of, for example, a wire of uniform resistance per
unit of length, it is obvious that as the telescope A is moved and a greater or less
length of said wire is brought into the galvanometer circuit that the resistance
thus interposed in said circuit will be increased or diminished; and as this length,
and hence this resistance, depends upon the angle of depression of the telescope, it
becomes a function of the angle of depression; and, equally, the deflection of the
galvanometer F, due to this change, is also a function of the angle of depression.
Therefore, knowing the height of the telescope above the level of the object, the
galvanometer deflection will indicate the distance of the object from the telescope,

page_text: for which purpose the galvanometer may be once for all graduated in any suitable
unit, such as meters or janis. Hence, if the galvanometer be located at a station
distant from that telescope, an observer at that distant station, by reading the
galvanometer, can recognize at once the distance of the object, while the person
stationed at the telescope has nothing to do but to keep it properly directed upon
the object.
The telescope pivot is carried upon a bar; G, Fig. 3, which is pivoted upon a
circular table, H. Placed in a groove around the periphery of this table is a
wire, I, Fig. 2, of conducting material, having a uniform resistance per unit of
length. Upon the bar G is supported a contact pieco or wiper, as will be more
particularly explained hereafter with reference to Fig. 3, which contact piece or
wiper always bears upon the wire I. At the distant station, Fig. 2, thero may be
arranged a circulur table, J, having around its periphery a wire, K, similar in all
respects to the wire I. Upon the table J is pivoted a bar, L, which bar L carries
a wiper or contact point which constantly presses upon the wire K. The contact
point on the bar G and the contact point on the bar L are connected by a
wire, N, which also includes the battery D. The ends of the wires K and I are
connected by wires O and P, and said wires O and P are respectively connected to
wires and R which lead to the terminals of a galvanometer, S. It will be
obvious, by a simple inspection of the drawing, Fig. 2, that the wires I and K at
the separate stations and the pivoted bars Ġ and L, together with the battery
and the galvanometer S, are connected in Wheatstone bridge circuit, and that a
movement of either the bar L or the bar G, displacing the contact pieces over
the wires K or I, will vary the resistance of the bridge arms so that the bridge
may be brought into or out of equilibrium by the movement of these bars upon.
their pivots. And further, it will be obvious that the fact when equilibrium is
produced in the bridge will be made manifest by tho' movement of the pointer of
the gulvanometer S. The construction is to be such, therefore, and the instruments
at the separated stations are to be placed with reference to one another so that
when the bar L makes the same azimuth angle with reference to one end of its
wire Kas does the bar G, then the bridge will balance and the galvanometer S
will show zero; so that if the telescope A, and consequently the bar G parallel
thereto, be directed upon the object, the galvanometer S will indicate zero when
the bar is placed similarly to the bar Gr. If then, on the table J there be
disposed a chart of the area to be protected on a reduced soule, such, for example,
as is shown in Fig. 2, the direction of the object froin the point of observation
will be indicated by the position of the bar L. For convenience in this respect the
bar Lis made with an opening containing a longitudinal wire, T; the position
of the object on the chart being of course along this wire. Also on the sides of
the opening in the bar L may be marked a scale of distances, in yards or moters.
The operation of the whole apparatus is therefore as follows: The telescope A
is depressed, and also moved in azimuth, until aligned with the object. Inasmuch
Be the distance of the object depends, as has already been explained, upon the angle
of depression, and as this angle is measured by the galvanometer F in terms of
distance, it is plain that if the galvanometer F be located at the station distant from
the observer, then from that instrument the distance of tho object can at once be
read off. Simultaneously the movement of the telescope A in azimuth disturbs the
balance of the bridge which includes tho galvanometer S. The observer at the
distant station then moves the bar I, until the galvanometer S, placed bear to him,
shows zero.
When that is done, the position of the object will be somewhere along
the line of the wire T; and its exact point along that wire T is immediately found
by noting on the scale on the bar L the distance corresponding to that shown by
the galvanometer F. The bearing and distance of the object thus being ascertained,
it remains simply to communicate this information, by any suitable means, to the
guns or battery.
It will be apparent that one of the great advantages of this instrument is that it
in directed by n sinale nbsorvor and that the simula novation of aliening it with

page_text: the target instantly causes, at the distant station, (the bar L there being suitably
manipulated) indications from which the bearing and distance of the object may at
once be recognized.
Referring now to Fig. 8, there is here illustrated, in detail, the mechanical con-
struction of the telescope A and its supports. The table H may be of any suitable
material, and should have embedded in it a ring, U, of hard rubber or other
insulating material, in which ring is the groove in which is placed the wire I. The
bar G is conveniently rotated on its pivot by means of the hand-wheel V, the
support for which wheel carries the contact point or wiper W. The inner end of
the telescope A is supported on the vertical screw a, which passes through the fixed
nut which is carried on, but insulated from, the bar G; the insulation being
placed below the nut. The screw a is rotated to depress and lower the telescope
by means of the hand-wheel c. Secured upon the screw is a'cylinder, d, of ebonite,
having upon its surface a spiral groove in which is laid the German silver wire
corresponding to the body C, Fig. 1. e is a contact spring which always bears
upon the wire C, and this spring is supported upon, but insulated from, the nut b.
The screw a which is of metal is secured to the cylinder d which is supported at its
upper end by a pin n, the ends of the wire C being connected to the screw a and
pin n. Hence the current from battery D passes to the pin n through wire C to
scrow a, to bracket & which supports the said screw, and back to battery. In this
device, instead of causing the telescope A to carry the contact and move it over a
fixed body, C, as in Figure the body C, by rotation of the screw a, is made to
move under the fixed contact piece e; the relation of the parts being thus merely
reversed. The circuit connections are the same as is indicated in Fig. 1; that is
to say, the battery terminals lead to both ends of the wire C wrapped upon the
cylinder d, and the terminals of galvanometer F connect respectively with the
contact wiper e and one end of the wire C. The movement of the telescope A in
azimuth is 350 degrees.
Having now fully described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondents, I declare that what I claim is
1. A depression range finder having a sight-bar or telescope pivoted to move in a
vertical plane, a body of conducting material and an electrical measuring instrument
in circuit with said body and said telescope; the said parts being constructed and
operating so that varying angles of depression of the telescope shall correspondingly
vary the length of the conducting body in circuit, and thus cause an indication by
said measuring instrument corresponding to the angle of depression and hence to the
distance of the object upon which the telescope is directed.
2. In combination with a depression range finder constructed and operating as set
forth, two bodies of conducting material located at distant stations, two contact
pieces maintained in contact with said bodies, one of said contact pieces being
controlled by the telescope of said depression range finder, and the other by a
pivoted bar, and the said contact pieces, conducting bodies, a galvanometer and a
battery being connected in Wheatstone bridge circuit; said parts being constructed
and operating so that when said bar at said distant station is adjusted at the same
Azimuth angle as said telescope, the galvanometer will indicate zero.
3. A position finder substantially as heroinbefore described containing & depres-
sion range finder and a device for showing the bearing of the object upon a chart
or map, the said apparatus being electrically operated and controlled to indicate the
distance and bearing of the object by the alignment of a single sight-bar or
telescope located at an observing station upon said object.
Dated this 1st day of Febru 1902
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.