Improvements in Telemeters and Range Finders.
Year: 1888

page_text: Date of Application, 15th Oct., 1888
Complete Specification Left, 13th Aug., 1889-Accepted, 12th Oct., 1889
PROVISIONAL SPECIFICATION.
Improvements in Telemeters and Range Finders.
I, GEORGE KILGOUR of 2 Victoria Mansions, Victoria Street, in the City of West-
minster, M.I.C.E., Civil Engineer do hereby declare the nature of this invention to
be as follows:-
I form a telemeter or range finder of a refracting telescope having in front of the
object glass an inclined mirror or mirrors whose function is to render visible any
objects at a considerable angle from the line of sight of the telescope. The eye piece
of the telescope is provided with the usual five wired diaphragm and sixth wire move-
able with micrometer or other means of measuring small angles.
The telescope I support in Y's on ordinary parallel plates and around the centre of
the telescope is a divided vertical arc.
In using the instrument observations are first taken with the telescope lying in one
direction in the Y supports and other observations when the instrument has been
reversed end for end. By this means the difference of angle in the two positions
between the telescope and a line passing from it to the distant object can be accurately
ascertained and the length of the instrument being a known quantity the distance of
the object can be ascertained.
11
171
1
1000
GEORGE KILGOUR.
COMPLETE SPECIFICATION.
Improvements in Telemeters and Range Finders.
I, GEORGE KILGOUR, of 2 Victoria Mansions, Victoria Street, in the City of West-
minster, M.I.C.E., 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 :-
I form a telemeter or range finder of a refracting telescope having in front of the
object glass an inclined mirror or mirrors whose function is to render visible any
objects at a considerable angle from the line of sight of the telescope. The eye piece
of the telescope is provided with the usual five wired diaphragm and sixth wire
moveable with micrometer or other means of measuring small angles.
The telescope I support in Y's on ordinary parallel plates and around the centro of
the telescope is a divided vertical arc.
In using the instrument observations are first taken with the telescope lying in one
direction in the Y supports and other observations when the instrument has been
reversed end for end. By this means the difference of angle in the two positions
between the telescope and a line passing from it to the distant object can be accurately
ascertained and the length of the instrument being a known quantity the distance of
the object can be ascertained.
In order that my said invention may be fully understood and readily carried into
effect I will proceed to describe the drawings hereunto annexed.
ON
DRAWINGS

page_text: Figure 4 shows the mirror and the cap in which it is held.
Figure 5 is an elevation of an apparatus which serves to slowly turn the telescope in
its Y supports.
Figure 6 shows: the wires and scale as they may appear in the field of view of the
telescope.
;
a and b are the parallel plates, they are mounted upon a tripod and they carry the
graduated circle con which horizontal angles may be measured. Above the circle c
is the plate d carrying verniers and capable of rotating in an horizontal plane. These
parts are furnished with the usual leveling appliances, clamps and slow movement
screws. e e arc arms fixed to the plate d and ff are Y bearings fixed upon the
arms to carry the telescope. fi f₁ are jointed straps which fold down over the
telescopo so that it may not be accidentally displaced from the Y's; these are
provided only by way of precaution. is the telescope tube, g¹ is the object
glass, g, the micrometer eye piece. g³ a right angle prism serving as a double
reflector. 9 are lateral windows in the head of the telescope in front of the
faces of the reflecting prism; these windows when the instrument is not in use
are closed by an outer cap or shutter. g g' are small front windows in the head of the
telescope, they however are usually closed; their use is to facilitate the adjustment of
the instrument and they also admit of the instrument being used for all the purposes of
a level or a theodolite. The front windows when open permit direct vision through the
telescope. gg are collars on the telescope to enter a corresponding recess in one of
the Y bearings. 9'g' are spirit levels. 98 is a graduated circle fixed on the telescope
on which vertical angles may be measured by the aid of a vernier carried by an
arm jointed to the plate d. is a ring which can be clamped fast upon the
telescope it carries a screw ' and a piston with a rod ³ which is thrust forward
by a spring. When the telescope is in place the extremity of one or other of the
arms e is held between the end of the screw and the rod 2 so that by turning
the screw when the ring is clamped to the telescope the latter is slowly rotated.
The arrangement of the wires seen in the field of view may be varied but that
shown by Figure 6 is convenient. iiii are four wires intersecting at a point in
the centre of the field. These wires are fixed and so is also the opaque scale k
which is notched on the edge and every fifth notch is deep so that the notches
may readily be counted. The centre or zero notch is marked by a perforation
below it. is another wire which is moveable laterally by turning the micrometer
screw; one complete turn of the screw moves it the distance from notch to notch
of the scale k. The head of the screw is graduated with a scale of 100 divisions
representing yards in the distance of the object. In measuring distance the instrument
is used as follows:-after it has been set up the telescope is first so placed that the
object is seen through one of the side windows and is exactly on the centre point of
the field. Then without moving anything but the telescope, the telescope is turned
end for end and is so placed in the Y's and the wire l is so moved that the image of
the object falls upon the intersection which this wire makes with that wire i which is
parallel to the edge of the scale. Then by counting the notches intervening between
the zero point and the wire and by reading the scale on the head of the micrometer
screw the distance in yards is ascertained.
In the place of the micrometer which I have described, other known micrometers
may be applied.
When it is required to measure angles of elevation the telescope is adjusted so that
the object is seen through one of the side windows accurately in the centre of the field,
then the angle of elevation is read upon the circle g³.
The form of this instrument admits of some variation although that shown is
generally preferred. Thus (as shown by figure 7) a double instrument may be made
consisting of two telescopes one or both provided with reflectors but with one eye piece
only; then two images of the object are seen at the same time and the distance between
them is measured by the micrometer. A double image micrometer is most suitable.
Such an instrument may be held in the hands when in use.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. A telemeter or range finder substantially as described and consisting of a telescope
with a reflector and a micrometer which telescope is supported on a stand in such
manner as admits of its being accurately directed upon the object and then reversed
end for end as herein set forth.
2. The combination with a telemeter or range finder in accordance with the first
claiming clause, of a graduated circle by which angles of elevation may be measured
as herein set forth.
3. The telemeter or range finder herein described either as represented by the
drawings or modified as herein specified.
1
A
1000
GEORGE KILGOUR.