Improvements in Range Finders.
Year: 1899

page_text: Date of Application, 26th June, 1899-Accepted, 5th Aug., 1899
COMPLETE SPECIFICATION.
Improvements in Range Finders.
I, GOTTHOLD LANGER, of 3145, Meramec Street, St. Louis, Miss., United States
of America, Mechanical Engineer, 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:-
My invention has relation to improvements in range finders, and consists in
the novel arrangement and combination of parts more fully set forth in the
specification and pointed out in the claims.
In the drawings, Fig. 1 is a rear elevation of the swinging arm of the device,
the roller at the free end thereof being omitted, and the upper stud, about which
said arm oscillates, being in section on line 1-1 of Fig. 2; Fig. 2 is a side
sectional elevation on line 2-2 of Fig. 4, showing parts in side elevation; Fig. 3
is a rear elevation of the supporting bracket, a portion thereof being broken
away; Fig. 4 is a front elevation of the device; Fig. 5 is a section on line 5-5
of Fig. 2; Fig. 6 is a face view of the terminal cup of the rotatable stud, about
the stem of which the rear arm oscillates; and Fig. 7 is a diagrammatic view
illustrating the application of the range-finder to a distant object.
The object of my present invention is to construct a range-finder with a per-
manent trigonometrical base, the length of said base constituting the shortest
distance between the longitudinal axes of the two telescopes with which my
device is provided. In my improvement one of the telescopes is rigidly
carried by an arm loosely oscillating about the axis of rotation of the other tele-
scope, the latter being first directed upon the object whose distance is to be
ascertained, whereupon the swinging telescope is directed against the same point
on said object, the lines of vision of the two telescopes constituting respectively
the hypothenuse and base of a right-angled triangle, and the distance between
the axes of the telescope (measured along the oscillating arm) constituting the
perpendicular of said triangle. The calculations are based on the relations sub-
sisting between the various sides of a triangle, the instrument always giving the
length of one side, and two angles, as will be better apparent from a detailed
description of the invention, which is as follows:
Referring to the drawings, 1. represents a ribbed plate or frame adapted to be
rigidly secured by means of the bolt and nut 2, and washer 21 to any standard
or base (not shown). Mounted in the upper tubular bearing 3 of the supporting
frame, and adapted to rotate within the same, is a stud 4, having a rearwardly
extending screw threaded stem 5 over the outer end of which is passed a tightening
nut & adapted to bear against a washer 7 interposed between it and the adjacent
wall of the frame.
Formed integrally with the stud 4 is a flange or disc 8 adapted to bear against
the front wall of the frame around the bearing 3, the nut 6 being adapted to
draw the disc 8 firmly against the frame, and thus prevent rotation of the stud 4,

page_text: when occasion arises to clamp the latter. The ribs 9 formed integrally with
the front face of the flange 8, connect the latter with one section 10 of the tele-
scope-socket, the opposite section 10¹ being formed integrally with a cup 11,
from the bottom of which projects outwardly a central boss or stem 12, having
an outer reduced extension 13 the base of which is smooth and balance screw-
threaded. Adapted to be passed over the smooth basal portion of the extension 13
is a ribbed arm 14, being rigidly secured to the cup by pins or screws 15, and
being provided at its free end with an outwardly projecting handle 16. When
the tightening nut 6 is loosened, the operator can, by seizing the handle 16,
swing or oscillate the arm 14 about the axis of the stud 4, the latter, together
with the cup 11, and telescope T clamped within the socket 10, 10¹ and flange S,
all rotating about the same axis as a unit, or as one piece. To ensure a rigid
connection between the arm 14 and cup 11, I pass a retaining nut 17 over the
stem 13, the nut forcing the arm against the annular ledge or shoulder formed
between the stem 12 and its extension 13.
Mounted along the front wall of the lower expanded portion of the arm 14
and protected by a suitable cover-plate 18, is a gear wheel 19 the shaft of which
passes respectively through the coverplate and the arm 14, the rear end of the
shaft carrying a pinion 20 confined in a housing 21 cast or formed with the
arm, and the forward projecting end of the shaft having secured thereto a needle
or index arm 22 protected by a rib or ledge 23 of the cover-plate, said needle co-
operating with suitable divisions or graduations formed on the face of the cover-
plate. The gear wheel meshes with a pinion 24 also mounted between the arm
and its cover-plate, the forward projecting end of the shaft or spindle of said
pinion having secured thereto, a second needle or index 25 likewise protected
by the rib 23, and a continuation 231 thereof formed on the arm, said needle
likewise co-operating with a second graduated circle superposed directly over the
first circle.
Adapted to swing or oscillate freely about the stem or boss 12 is a second
arm 26, the hub portion of which loosely embraces the stem 12, being confined
between the rigid arm 14, and the bottom of the cup, the peripheral walls and
face of the latter being cut away or recessed sufficiently so as to allow for the
free passage and oscillation therethrough of the narrow portion of the said
arm 26, the sides of the recess thus formed in the face inclining so as to allow
the arm 26 to describe a length of arc as the capacity of the instrument may
require (in the present case about 10 degrees on each side of a vertical line pass-
ing through the axis of oscillation of the arm) but limiting its oscillation when
the arm comes in contact therewith (see Figs. 5 and 6).
The oscillating arm has formed integrally therewith a toothed segment 27 the
teeth of which mesh with the lower pinion 20 confined within the housing 21
of the relatively stationary arm 14, the wall of the housing being cut away
sufficiently to allow the toothed edge of the segment 27 to mesh with said pinion,
the body of the segment projecting laterally and to one side of both arms when
both arms are parallel. The arm 26 is provided with a handle 28 the base of
which forms one section of the clamping socket for the retention of the second
telescope T; the other half or section of the clamping socket being formed
directly with the arm 26. The arm 14 is provided with an opening 29 through
which may be read the degree graduations, or limb 30 marked on the toothed
segment, the upper wall of the opening being provided with a pointer or needle 3.1
in connection with which the limb 30 can be read. When both arms (that is to
say, their longitudinal axes), are parallel, the needle 31 will point to zero on the
limb 30, the pinion 20 being in engagement with the third or fourth tooth from
the adjacent edge of the toothed segment. When once the arm 14 is rigidly
clamped to the supporting 'frame, then the operator can readily oscillate the
arm 26 and segment 27 about the stem 12. When the arms 14 and 26 are
parallel and the pointer 31 points to zero on the limb 30, the telescopes T and T¹
are parallel, the longitudinal axis of the telescope T¹ being perpendicular at all

page_text: times to the longitudinal axis of the arm 26. The arm 26 is so shaped as to
bring the centres of the two telescopes in a line parallel to the plane of oscilla-
tion of the arm 26; and hence the shortest distance between the telescopes may
be measured along this line. This distance is marked X-X in Fig. 2, and serves
as the permanent base line from which the trigonometrical calculation, previously
referred to, can be made.
The relation between the diameter of the pinion 20 and the diameter of the
toothed circle of the segment 27 is such that when the latter has been oscillated
10 degrees, the pinion, and hence the gear wheel 19 will have made one revolu-
tion; and the relation between the gear 19 and pinion 24 is such that one revolu-
tion of the gear wheel imparts ten revolutions to the pinion 24, and needle 25,
or in other words one-tenth of a revolution of the gear wheel 19 (which means
an oscillation through an angle of one degree for the segment 27 or arm 26) will
impart one revolution to pinion 24 and needle 25. The circumference of the
graduated circle with which the needle 25 co-operates, represents (with the pre-
sent arrangement of multiplying gear) one degree of swing for the arm 26 and
telescope T carried by it, and hence to read a fraction of a degree the circle re-
ferred to may be divided into any number of arbitrary divisions. Likewise may
the lower circle, or that with which the needle 22 co-operates. Of course it is
only too obvious that the object of the multiplying gear here described is to
enlarge the surface over which a degree of oscillation may be sub-divided, so as
to make the reading easier, and the results more accurate.
The special application of the device as a range-finder will now be apparent :
Upon loosening of the nut 6 the cross hairs of the telescope T are first directed
upon an object whose distance is to be ascertained. This is done by seizing the
handle of the arm 14 and swinging the latter (there being a rigid connection
between it and the telescope T as already explained) until a particular spot on
the object is sighted by the cross-hairs of said telescope T. The parts are then
firmly clamped by the tightening nut 6. The handle of the arm 26 is then
seized, and the latter is oscillated about the stem 12, until the cross-hairs of the
telescope T sight the same spot on the same object. That the telescope may sight
the sanie spot it follows that their lines of sight must necessarily converge toward
such point, and hence the triangle forming the basis of calculation is complete. The
perpendicular of this triangle is the distance between the axes of the two tele-
scopes, this distance being the line X-X, and constituting the permanent line
from which one of the other sides of the triangle can be calculated. The angle
through which the arm 26 has been swung to cause the line of sight of the tele-
scope T to converge to the same point to which the cross-hairs of the telescope T
are directed, will be indicated on one or the other of the graduated circles of the
front face of the arm 14; but this angle is the same as the angle between the base
and the hypothenuse of the large triangle to be calculated. Thus in the diagram-
matic view in Fig. 7, let " a" be the angle to which the arm 26 has been swung,
from its parallel postion to the arm 14, to enable the operator to sight the same
point as that to which the telescope T is directed. Then, from the similarity
of triangles, the angle "a" is equal to the angle a, of the large triangle; but
as the angle between the base and perpendicular (line X-X) of the large triangle
is a constant one--ninety degrees-then, knowing the angle a', and the length
of the perpendicular (X-X) one can always calculate the length of the base ","
that is to say, the distance of the object sighted. It is therefore obvious that the
constant base line, under the present invention, corresponds to the perpendicular
of a triangle, whose base is the distance of the object sighted. Of course, the
distance might be read along the hypothenuse which could also be calculated
if desired.
Having the angle a, it is possible to prepare a table to which the operator
could refer, and note the distance of the object corresponding to any angle sighted.
That the arm 26 may, in its swinging, be stiffened and guided, I provide the
same with an arm or bracket 32 at the free end of which is mounted a roller 33

page_text: travelling in a dove-tailed groove or way 34 formed at the outer edge of the
main frame 1.
In practice, instead of compelling the operator to resort to a table of calculated
distances, each instrument will have the distance corresponding to any angle to
which the toothed segment has been swung to sight the common point of any
object, marked on the face of the graduated circles of the arm 14, in connection
with the graduations indicating the degrees and parts of degrees marked on such
circles. These distances will be carefully calculated on the testing grounds,
and then marked on the instrument so tested.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what I
claim is:-
1. A range-finder comprising a telescope, a rotatable stud to which said tele-
scope is fixed, the axis of rotation of the stud corresponding to the transverse
axis of rotation of the telescope, an arm rigidly connected to the stud at right
angles thereto, and adapted to rotate the latter, a second rigid arm loosely de-
pending or oscillating about the axis of the stud and located adjacent to and
extending in the same direction, with, the first arm, a second telescope secured to
the second arm, with its longitudinal axis at right angles to the length of the
arm, both telescopes being adapted to be directed against a common point of the
same object sighted, substantially as set forth.
2. A range-finder comprising a telescope, a rotatable stud to which said tele-
scope is fixed transversely to the axis of rotation thereof, the transverse axis of
the telescope and the longitudinal axis of the stud being in the same straight
line, a rigid arm connected to the stud at right angles thereto, a second rigid
arm adapted to oscillate about the axis of the stud, and located adjacent to the
first arm, and extending in the same direction therewith, a telescope carried by
said second arm, and adapted to oscillate in a plane parallel to the plane of rota-
tion of the first telescope, the axes of the telescopes being connected by a line
parallel to said plane of oscillation, a toothed segment carried by said second
arm, multiplying gearing carried by the first arm and co-operating with the
teeth of said segment, index arms connected to the gearing of the first arm,
graduated circles co-operating with said index arms, a graduated limb on the
toothed segment, and means connected to the first rigid arm for limiting the
swing of the oscillating arm, the parts operating substantially as, and for the
purpose set forth.
3. In a range-finder, a suitable rotatable stud, a telescope fixed thereto, a rigid
arm connected to the stud at right angles thereto, means for clamping the stud
against rotation, a second rigid arm loosely oscillating about the stud and located
adjacent to the first arm and extending in the same direction therewith, inclined
walls carried by the stud for limiting the degree of oscillation of said second
arm, a telescope secured to said second arm, and means for indicating the angle
which the lines of sight of the two telescopes make with one another when con-
verged to a common point, substantially as set forth.
4. In a range finder, a suitable rotatable stud, a sectional telescope-socket
carried thereby, a cup formed integrally with one of the socket sections, a boss or
stem having a reduced extension projecting from the bottom of the cup, an arm
passed over the base of the extension of the stem and rigidly secured to the adja-
cent end wall of the cup, a nut passed over the projecting end of the stem-exten-
sion, the peripheral wall and face of the cup being recessed to a suitable depth,
and the sides of the recesses being inclined toward each other, a series of multi-
plying gears mounted on the arm, and having index arms actuated by the spindles
or shafts of the respective gears, the index arms co-operating with the division
marks of properly graduated circles marked on the face of the arm, a second
arm loosely oscillating about the stem in the cup and carrying a telescope
oscillating with the plane of rotation of the first telescope, a toothed segment co-

page_text: operating with the series of multiplying gears on the first arm, a graduated limb
on said toothed-segment, a pointer on the first or rigid arm co-operating with
said graduated limb, the parts operating substantially as and for the purpose
set forth.