An Improved Range-finder.
Year: 1889

page_text: Date of Application, 17th Apr., 1889
Complete Specification Left, 17th Jan., 1890-Accepted, 12th Apr., 1890
PROVISIONAL SPECIFICATION.
An Improved Range-finder.
HARRY HOWLETT YOUNG, of Park House, Ellenslea Road, St. Leonards-on-Sea
in the County of Sussex, Captain Madras Staff Corps, do hereby declare' the nature of
this invention to be as follows :
'
The object of my invention is to provide a simple and efficient range-finder.
An important feature of my said invention is the employment of a mirror or
reflector arranged to be moved to and fro in an inclined path by means of a helical
groove of varying pitch formed in the surface of a cylinder or cone which is provided
with suitable means for rotating it about its axis. In combination with this movable
mirror, or reflector I employ a fixed or stationary mirror or reflector which is arranged
at a suitable angle or inclination beneath (or above) the said cylinder or cone. These
mirrors or, reflectors are so arranged relatively to each other that the object sighted
will be reflected from the movable mirror to the stationary mirror (or vice versa) and
thence towards the observer. When the movable mirror is in its lowermost position
it will reflect towards the stationary mirror the rays of light from an object at a
distance from the observer of say 500 yards, and, as the cylinder or cone is rotated
about its axis, the movable mirror will be raised or moved upward in its inclined
path so that objects at a greater distance from the observer will be reflected to the
sight hole or sighting point.
•
An index or pointer is provided for indicating the range on a dial. This index or
pointer may conveniently be fixed upon the spindle or axis of the cylinder or cone.
The body of the cylinder or cone may if desired, be cut away except at the part
occupied by the helical groove and such other parts as are required for supporting
the same,
I sometimes so, construct the apparatus that a straight line extending from the sight
hole or sighting point through a slit or aperture in the cylinder or cone will intersect
the stationary mirror at the required point to enable the observer to see the reflection
of the object whose distance from the observer is to be ascertained. The said slit or
aperture is so arranged that it will follow the movement of the movable reflector when
the cylinder or cone is rotated.'
My improved, range-finder is chiefly designed to be held in the hand when in usc.
It may, however, be attached to any convenient support upon a gun or otherwise.
Dated this 17th day of Anril. 1889.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improved Range-finder.
I, HARRY HOWLETT YOUNG, of Park House, Ellenslea Road, St. Leonards-on-Sea,
in the County of Sussex, Captain Madras Staff Corps, 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:
:-
The object of my invention is to provide a strong simple and efficient range-finder
which can be attached to a piece of ordnance or to a rifle or other fire-arm, or can be
easily carried by an infantry soldier in addition to his rifle and ordinary equipment,
and which requires only one observer and can be used by a person of ordinary intelii-
gence after very little training or instruction and without recourse to calculation, and
which possesses other advantages hereinafter mentioned.
An important feature of my said invention is the employment of mirrors one of
[Pren 827

page_text: which is movable or adjustable relatively to the other and which are so arranged tha
the object observed by direct vision will be reflected from one to the other of the said
inirrors and thence to the eye of the observer when the movable mirror is properly
adjusted. The device for adjusting the movable mirror has combined with it a suitable
range-indicator. My improved range-finder is, moreover, provided with an ordinary
or other suitable sight and is so constructed that, when an object is seen directly in
line with the said sight and the movable mirror is adjusted so that the said object can
also be seen by double reflection by the aid of the mirrors, the distance of the said
object from the observer will be indicated by the aforesaid range-indicator.
Therefore, with my improved instrument, the range can be ascertained without the
aid of any other measurement and without the aid of pickets or other supplementary
apparatus.
In the accompanying drawing,
Figure 1 is a plan
Figure 2 a vertical longitudinal central section, and
an adjusting-
Figure 3 a front elevation of one form of my improved range-finder.
Figure 4 is a front elevation, drawn to an enlarged scale, showing
cone hereinafter described forming a part of the said range-finder, and
Figure 5 is a diagram illustrating the operation of the said range-finder.
Like letters indicate corresponding parts throughout the drawing.
a is a box or casing, which is provided with sighting-apertures a¹, a², and to which
is attached a sight comprising a metal rod or wire 6 carried by a cross-bar attached
to the forward ends of telescopic rods e which are arranged one on each side of the
said box or casing a, and the sections of which of largest diameter are firmly secured
to the said box or casing. d is a mirror which is firmly secured in the box or casing a
at a suitable angle to the horizontal plane. e is another mirror which is movable or
adjustable in an inclined path, and which is so arranged that the object observed
through the aperture a¹ by the aid of the sighting wire b will be reflected by the said
adjustable mirror e and, when this is properly adjusted, the reflection of the object
will be thrown upon the fixed or stationary mirror d and thereby again reflected so
that the reflection may be seen through the sighting-aperture a³.
The said mirror e is attached to a
extends through a block g fitted to slide in a slot in an inclined portion of a
plate provided with a pin or stud f, which
bracket h secured to the box or casing a. Springs are connected at their upper end,
by means of a cross-bar k, with the said pin or stud f'. The said springs are secured
at their lower end to the box or case a and tend to hold the mirror e in its lowermost
position.
is a truncated cone which is formed with a helical surface of varying or
differential pitch. The pin or stud f' bears against this helical surface, which is so
arranged that, by turning the said cone in one direction, the mirror e may be moved
upward in its inclined path, and, by turning the said cone in the reverse direction, the
downward movement of the said mirror in its inclined path under the influence of the
springs may be permitted. By these means, the mirror e may be adjusted relatively
to the mirror d in such a manner that an object at any distance from the observer
within the limits of range for which the apparatus is constructed, will be reflected
from the mirror e to the mirror d and thence to the sighting-aperture a³, when the
apparatus is held in such a position that the said object is in the same straight line as
the sighting rod or wire b and the sighting-aperture a¹.
The pitch of the said helical surface should decrease proportionately to the decrease
in the distance through which the mirror e requires to be moved for any given
increase of range, that is to say, the pitch of the said helical surface should decrease
in proportion to the perspective.
To provide for rotating the adjusting-cone 7 and for simultaneously indicating the
range of an object, I mount the said cone upon a spindle or shaft m, and I fix upon
this shaft a worm-wheel n with which is geared a worm p formed or fixed on a spindle
or shaft pl. This spindle p¹ is mounted in suitable bearings in the sides of the box or
casing a, and is provided with a milled wheel or head p* for facilitating the turning of

page_text: the said spindle to adjust the cone l. The worm-wheel n is provided with a graduated
scale for indicating the range. I prefer to combine, with the said worm-wheel, a
Vernier scale formed on a disc q having a hevelled edge and firmly attached to a
bridge or cross-bar q' in which the upper end of the spindle m has its bearing, the
lower end of the said spindle having its bearing in the bracket h.
The apparatus in operated as follows, viz. The sighting bar or wire bis first
moved outwards as far as the telescopic rods c will allow. The object whose distance
from the observer is to be ascertained is then observed through the aperture a', the
apparatus being so held that the said object or any particular part thereof is in the
same straight line with the rod or wire and the eye of the observer. The mirror e
is then, by the means above described, moved upward or downward in its inclined
path until the object or the part thereof seen directly through the aperture a¹ and in
line with the rod or wire b, can also be seen, through the aperture a³, reflected in the
mirror d, as will be more readily understood by referring to the diagram Figure 5;
to obtain an accurate indication of the range, the said object or the particular part
thereof in line with the ordinary sight should appear in the same position relatively to
the reflection of the lower edge of the mirror e in the mirror d, as it apparently
occupies relatively to the rod or wire b. The range or distance of the object from the
observer will then be indicated on the graduated scale upon the wormn-wheel n. By
arranging the mirrors as above described so that the object whose range is to be
ascertained is reflected from the lower edge of the mirror e, I obviate any liability to
error in the adjustment of the apparatus, as no object short of the range will be
reflected by the mirrors when the instrument is at its adjustment.
It will be seen that the measurements are effected by the simple rotation of a
spindle to effect the adjustment of the movable mirror or reflector in one or the other
direction as required. Moreover the rotary movement will be great compared with
the distance through which the mirror is moved, consequently the range can be
ascertained very accurately.
I sometimes arrange suitable tubes in combination with the sighting-apertures, as
indicated by dotted lines in Figure 2. These tubes can, if desired, be provided with
lenses to adapt the instrument for the measurement of very long distances. In this
case, I can dispense with the sighting arrangement and insert a split hair in the upper
lens. The dial-plate and adjusting-cone may, if desired, be made to revolve by a
device similar to that used in a stop-watch or chronograph. It is obvious, moreover,
that any other suitable means may be employed for expediting the adjustment of the
range-finder.
Any suitable mirrors or reflectors may be used in my improved range-finder.
By increasing or diminishing the height of the adjusting-cone or the pitch of the
helical surface thereon, the instrument can be adapted for longer or shorter ranges.
The said adjusting-cone may, if desired, be a complete instead of a truncated cone.
Any desired range may be selected as the zero-point for my instrument. In the
instrument shown, the zero or minimum range indicated thereby is five hundred
yards, as it is generally considered that, with the modern weapons, a range-finder to
indicate shorter ranges than this is unnecessary. For sporting purposes, however, the
instrument can be adapted for shorter ranges, and, if desired, for indicating the range
in feet.
Instead of arranging the adjustable mirror so that it can be moved up and down in
an inclined plane, I sometimes mount the said mirror upon pivots or trunnions, and
provide suitable means whereby the said mirror may be turned about the axis of the
said trunnions in one or the other direction as required, according to whether
the range of the object is greater or less than that for which the instrument is
set. In this case, I provide a micrometer-screw or other suitable range-indicator
which will be operated simultaneously with the adjustment of the mirror about its
axis.
Moreover I sometimes so construct the instrument that the mirror which is
adjustable in an inclined path is also adjustable about a pivot or axis for the purpose
above specified.

page_text: It will be seen that my instrument can be easily used by a single observer without
assistance, no base being required, and the movable mirror being set or adjusted and
the range-indicator operated by the simple rotation of a spindle without the necessity
for adjustment of any other part of the instrument.
My improved instrument, moreover, affords the following advantages, viz. :-It is
not liable to injury by any shock or concussion to which it may be subjected in'
ordinary use, there being no parts liable to get out of order, and the springs yielding
under shock or concussion and thus obviating liability to breakage of the parts. It
can, as above stated, be easily carried by an infantry soldier in addition to his rifle
and equipment. After a short period of practice, observations can be made very
rapidly, the observations being made without the aid of extra appliances and without
recourse to calculation.
The adjusting-cone may, as above stated, be a complete instead of a truncated cone;
or a cylinder provided with a helical surface of varying pitch may be substituted for the
cone for the purpose of adjusting the movable mirror and adjusting the range indicator.
The said adjusting-cone provided with the helical surface of varying or differential
pitch is very advantageous in cases where it is required to effect adjustments through
very small distances while moving an indicator through an appreciable space. The
body of the said adjusting-cone may, if desired, be cut away except at such parts
as are required to form and support the said helical surface.
I sometimes prolong the spindle m so that it extends through the bracket h, and I
fit upon it below the said bracket a hollow cone or a portion of a hollow cone having
a spiral or helical slit and so arranged that a straight line extending from the sighting-
aperture through the said slit in the hollow cone will, whatever may be the position
of the adjusting-cone, intersect the stationary mirror d at the required point to enable
the observer to see the reflection of the object whose distance from the observer is to
be ascertained. Or I make the adjusting-cone hollow and increase the dimensions of
the same and forin a spiral or helical slit therein for the purpose above specified.
My improved range-finder can be advantageously connected by a universal-joint to
a pin, screw, plug, plate or other suitable contrivance, which may be fitted in the
muzzle of a rifle, or mounted upon a tripod, or screwed into a fence or into a branch
of a tree, or secured in any other convenient manner to a suitable support; or, if
desired, the said range-finder may be held in the hand while in use.
It is obvious, moreover, that the construction of my improved instrument may be
somewhat further modified without departing from the nature of my said invention.
For instance, instead of making the mirror e movable or adjustable, I may fix this
mirror and provide a suitable device for adjusting the mirror d in its inclined plane
or about pivots or trunnions, and connect this device by suitable gearing with the
device for operating the range-indicator, so that the said devices will be operated
simultaneously.
The mirrors, instead of being arranged as shown in the drawings, in combination
with a horizontal sighting rod or wire, may be arranged in combination with a vertical
sighting rod or wire. The mirrors, in this case, would be situated one on the right
hand side and the other on the left hand side of the line of sight, as they would
appear in Figure 5, assuming this Figure to be a plan instead of a side view; and the
observer would, in this case, have to turn his eye toward the right from the line of
sight to see the reflection of the object sighted. Moreover the mirrors may be
arranged at a greater or less distance apart than that shown in the drawing.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I wish it understood
that I claim :-
First. A range-finder wherein provision is made for ascertaining the distance of an
object from the observer by the aid of two simple mirrors or reflectors one of which
is movable or adjustable relatively to the other for the purpose above specified,
without the aid of any other measurement or apparatus, substantially as hereinbefore
described.

page_text: Second. A range-finder comprising mirrors or reflectors which are so arranged
that the object observed will be reflected from one to the other of the same and thence
to the eye of the observer, and one of which is provided with suitable means whereby the
simple rotation of a spindle will effect the adjustment of the said mirror according to
the distance of the object from the observer and the simultaneous operation of a range-
indicator, for the purposes above specified.
Third. The combination, in a range-finder, of a fixed or stationary mirror or
reflector and a mirror or reflector which is movable or adjustable in an inclined path,
or both in an inclined path and about a pivot or axis, substantially as, and for the
purposes, set forth.
Fourth. A range-finder wherein a fixed or stationary mirror or reflector and a
movable mirror or reflector are combined with each other and with a range-indicator,
and wherein the said mirrors are so arranged that, when the instrument is adjusted
for any particular range, no object within a shorter range will be reflected by the said
mirrors, for the purposes above specified.
Fifth. The combination, in a range-finder, of a sighting-device, mirrors or reflectors
one of which is movable or adjustable relatively to the other and whereby the
observer can see a reflection of an object seen directly by the aid of the said sighting-
device, and a range-indicator operated simultaneously with the adjustment of the said
movable mirror, for the purpose above specified.
Sixth. The adjusting-cone provided with the helical surface of varying or differential
pitch.
Seventh. The combination, with the fixed or stationary and the adjustable mirrors
or reflectors, of an adjusting cone or cylinder having a helical surface of varying or
differential pitch and adapted by its rotation to cause the movement of the said
adjustable mirror, a range-indicator and suitable means for simultaneously turning
the said cone or cylinder about its axis and operating the said range-indicator,
substantially as, and for the purposes, set forth.
Eighth. The improved range-finder constructed substantially as described with
reference to the accompanying drawing and operating as, and for the purposes, above
specified.
Dated this Seventeenth durs of Tanner-1000
H. H. YOUNG.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.