Improvements in Range-finders.
Year: 1889

page_text: Date of Application, 23rd Sept., 1889
Complete Specification Left, 23rd June, 1890-Accepted, 23rd Sept., 1890
PROVISIONAL SPECIFICATION.
Improvements in Range-finders.
I EDWIN OADES, of Linden House, Brond Street, Wokingham in the County of
Berks, Auctioneer and Surveyor, do hereby declare the nature of my invention for
"IMPROVEMENTS IN RANGE-FINDERS" to be as follows:-
The improvements in rangefinders consists of approximately measuring distances
with telescopes by refraction produced by using prismatic shaped glasses or lenses
with the assistance of a simple apparatus to measure the amount of refraction, auto-
matically giving the distance of an object from the observer on a graduated scale
with vernier, consisting of two arms or bars (A and B Fig. 1) jointed like a pair of
compases (H) or dividers, a sliding plate with vernier travelling nearly the whole
length of the arms opening or closing them in sliding from one end to the other.
Attached to the vernier plate and sliding on one of the arms is a micrometer or slow
motion screw D, clamping screw E, and sliding clip F, the graduated scale to be
attached to the arm A, the groove in the arm B in which the vernier plate slides to
be straight or slightly curved.
If the graduated scale is ten inches long, divided into ten divisions, each of which
is subdivided into 20 parts, which is again divided into 10ths by the vernier, so that
the dividers or arms being set to open and close part of an inch by the slide and
vernier travelling the length of same, the part of an inch would be divided into two
thousand parts or be capable of moving the arm the ten thousandth part of an inch
and automatically registering same with the vernier, to be read with or without
microscope 10 x 20 x 10 = 2000; 10 x 20 x 10 x 5 = 10,000.
If a single telescope with tripod stand is used with body clamping and micrometer
screws, the prismatic shaped object glass or lens must be capable of being half
turned round.
The arm with the graduated scale A to be fixed to the telescope with two screws
and capstan shaped nuts and the other arm to be attached to a sliding diaphragm
with cross wires, in front of the eye pieces. A second diaphragm with cross wires
being fixed in front of the eye pieces.
To find the distance to any object within the range, set the ②C :n vernier at zero
on the graduated scale and clamp with body clamping screw, intersect the object
with the cross wires on fixed diaphragm (for example flag staff Fig. 2) turn the
object glass half round, the flag staff will then appear some distance to the right or
left of the cross wires, slide the vernier plate up the arms until the cross wires of the
sliding diaphragm intersect the flag staff, clamp and perfect the intersection with
vernier-micrometer screw, which will show the amount of refraction, read off the
distance on graduated scale with vernier.
With a single telescope and no stand, fitted with two prismatic shaped glasses or
lenses formed of one prismatic shaped lens cut horizontally and reversed (Fig. 4) so
that one half would refract the object to the right the other half refract the object to
the left, slide the vernier plate up the arms or dividers A and B until one wire inter-
sects a portion of the flag staff seen on the top half lens, and the other wire intersects
the other part of flag staff on the lower half lens which will show the amount of
refraction. Read off distance on graduated scale with vernier.
If two telescopes or binoculars are used, the prismatic shaped glasses or lenses
may be used in one or both telescopes, a single diaphragm with cross wires could be
used to each telescope fixed in the usual way, one arm of the dividers being fixed to
each telescope with screws and capstan shaped nuts or other convenient way for
adjustment, the sliding vernier plate then being used to converge the telescopes

page_text: (instead of acting directly on the diaphragms) until the cross wires in each telescope
coalesce with flag staff road off distance on graduated scale with vernier.
The binoculars can be fitted with sliding diaphragm the same as the single
telescopes if preferred.
To be used in preference with a stand, but if not so used the two eye pieces to be
about 2 inches apart to enable the observer to look through both telescopes at once
as binoculars.
The prismatic glasses or lenses to be made at such angles as may be most suited
for the range, either solid, part liquid or two or more lenses, loose or cemented
together.
One or more prismatic glasses or lenses to be used to each telescope if required.
The eye pieces to be used to magnify the cross wires and invert the object sighted
if required.
The arms or dividers could be fixed inside the telescope and the micrometer &
clamping screw altered in shape & position to enable the rangefinder to be more
conveniently packed in a smaller caso.
My invention of "Improvements in Rangefinders" consists of measuring distances.
with telescopes by refraction produced by using prismatic shaped lenses and a simple
apparatus consisting of a pair of arms or dividers, measuring the amount of refraction,
automatically giving the distance of an object, from the observer on a graduated
scale with vernier.
Dated this Twenty-first day of September 1889.
EDWIN OADES,
Auctioneer and Surveyor, Wokingham.
COMPLETE SPECIFICATION.
Improvements in Range-finders.
I, EDWIN OADES of Broad Street, Wokingham, in the County of Berks Auctioncer
and Surveyor, 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 said invention is to provide an improved range finder or apparatus
whereby distances can be more readily and accurately measured or ascertained than
by apparatus of the same kind or class hitherto constructed.
An important feature of my said invention is the utilization of the refraction of
light in its passage through prismatic lenses for measuring or ascertaining the distance
of objects from the observer.
For this purpose I provide for the relative angular adjustment of prismatic lenses or
of a prismatic and an ordinary lens in such a manner that the image of the distant
object refracted by one of the said lenses will be brought into the same line of sight
as the image seen through the other lens. It is evident that the amount of refraction
will vary according to the angle of incidence of the rays of light from the object
sighted, and consequently according to the distance of the object from the observer.
In some instances I provide a prismatic leus so arranged that it can be reversed after
being sighted upon the object, or 1 provide two prismatic lenses arranged in opposite
directions. I am thus enabled by measuring the degree of refraction to ascertain the
said distances, (more especially in the case of a long distance) with great accuracy
and expedition.
In the accompanying drawing I have shown how my said invention may be con-
veniently and advantageously carried into practice.
Figure 1 is a plan.
Figure 2 is a transverse section on the line x, x Figure 1, and
Figure 3 is a transverse section on the line y, y Figure 1 showing one form of my
improved range finder

page_text: Figure 4 is a plan, and
Figure 5 is a transverse section on the line, Figure 4 illustrating a modification
thereof..
Figure 6 is a similar view to Figure 5 showing the parts in a different position.
Figure 7 is a vertical section showing another modification.
Figure 8 is a side elevation.
Figure 9 is a horizonal section on the line ' ' Figure 8 and
Figure 10 is a vertical transverse section on the line
another modification.
Figure 11 is a transverse section. and
Figures 8 and 9 showing
Figure 12 is a side elevation partly in vertical longitudinal central section on the
line Figure 11 illustrating a still further modification.
Figare 18 is a side elevation and
Figure 14 is a plan some of the parts being removed illustrating a stand, tripod or
support for my improved range finder.
Like letters illustrate corresponding parts throughout the drawings.
A A are telescopes each of which consists of sliding tubes adjustable relatively to
each other for focussing purposes by means of racks B pinions and hand wheels D
(as more clearly shown in Figure 2) or in any other convenient manner. The
telescopic tubes or telescope A is provided with lenses substantially similar to those in
an ordinary telescope, and with a fixed diaphragm E having crossed wires or hairs E'
in front of the eye piece or magnifying lenses of the telescope.
The telescope A is hinged or jointed at F to the telescope A¹ so that the free
extremities of the said telescopes are capable of being moved to or from each other
like the legs of an ordinary compass. G is a prismatic lens fitted in the telescope A'
and taking the place of the usual object glass, the other lenses are similar to those
usually employed. The bevel of the said prismatic lens when intended for long ranges
is very slight and is not perceptible for very short ranges. At long ranges however
the image of the object sighted will be refracted to the right or left according to the
direction of bevel of the said lens the extent of the said rofraction depending upon
the distance of the said object from the observer. For short ranges the bevel of the
said lens is proportionately increased. His a block or plate having a dovetail or
T-shaped groove H'in which is adapted to fit a correspondingly shaped strip or piece J
upon the outer tube of the telescope A so that the said block or plate is, capable of
moving freely thereon. Jare guide pieces or strips firmly attached to the said
outer tube of the telescope A for further directing and supporting the slide block or
plate H. K is another strip or piece upon the outer tube of the telescope A¹ having
a curved or slanting groove K' in which engages a pin or projection H2 upon the
slide block or plate H. By moving the said slide block or plate H away from the
eye pieces of the telescopes and towards the object glasses, the telescope A¹ will
be moved more or less out of a parallel line with the telescope A and will be
caused to assume an angular or inclined position relatively thereto. The slide block
or plate His provided moreover with a vernier scale H³ and is arranged in com-
bination with a graduated scale A2 upon the telescope A or upon the guide strip
or piece J¹ by means of which the range can be accurately read off as hereinafter
described. L is another slide block or piece also provided with a dovetail or
T-shaped groove L' and arranged to move freely upon the strip or piece J. The
said slide block or piece L is connected with the slide block or plate H by means
of a micrometer screw M by operating which the fine adjustment of the telescope A
can he effected. L² is a clamping screw for securing the said slide block or piece L
in position whilst the said fine adjustment is being effected. The telescope A' is also
provided with a fixed diaphragm E and cross wires or bairs E similar to those
provided in the telescope A. When the arrow upon the vernier scale H³ is at zero
upon the graduated scale A² the axes of the said telescopes A A' are parallel to each
other.
The telescope A is when intended for use with infantry preferably secured upon the
upper extremity of a tripod stand by means of a swivel or universal joint, and a

page_text: suitable set screw or thumb screw is provided for clamping or fixing it in position
when required. The said telescope A may be however attached to a gun or elsewhere,
or in some cases when constructed especially light and otherwise arranged for that
purpose held in the hands like an ordinary telescope or binocular. In the latter case
the telescopes are preferably arranged at a convenient distance apart so as to permit
the observer to look through both eye pieces at once if desired.
By means of the graduated scale A2 and the vernier scale H³ I am enabled to
ascertain a very slight movement of the movable telescope A' away from the telescope A
after the latter has been fixed or sighted upon the object the range of which it is
desired to measure. For instance if the said graduated scale A is ten inches long
and divided into ten divisions, which divisions are again subdivided into twenty parts,
each of the latter can be divided into tenths by the vernier. If therefore the
telescope A be so arranged that it can be opened or moved away from the telescope A
one fifth of an inch at the widest part by moving the slide block or plate H the entire
length of its travel, the said fifth part of an inch would be divided into two thousand
parts, and the telescope A' could be moved or adjusted the ten thousandth part of an
inch relatively to the telescope A which adjustment could be read off by means of the
vernier scale with or without a suitable microscope.
In using the apparatus the arrow upon the sliding block or plate H is set at zero
upon the graduated scale A2 and the object the range or distance of which it is desired
to ascertain is sighted through the telescope A which latter is adjusted until the said
object is properly and accurately intersected by the cross wires E' on the diaphragm E
and if on a tripod stand or other support is then clamped or secured in position.
Upon looking through the telescope A¹ the said object will then be seen owing to the
refraction caused by the prismatic lens or object glass G at a certain distance to the
right or left of the centre of the cross wires according to the direction of the bevel.
The slide block or piece H is then moved away from the eye pieces of the said
telescopes and towards the object glasses so as to cause the said cross wires in the
telescope A io intersect or nearly to intersect the object, the slide block or piece
then clamped in position by means of the screw L and the fine or final adjustment is
effected as above stated by means of the micrometer screw M. When the object
is accurately intersected by the cross wires E¹ of both the telescopes A and A¹ the
range or distance of the said object from the observer can be read off upon the scale A*
by means of the vernier scale H³ upon the slide block or plate H.
is
Figures 4 and 5 illustrate an application of my invention to a single telescope.
In this case the ordinary telescope is dispensed with and the telescope A¹ having the
prismatic glass or lens G is fitted with another diaphragm E² with cross wires or
hairs E3 (Figure 6). The cross wires or hairs E', E³ are preferably countersunk in
the diaphragms E E and the said diaphragm E2 is arranged in close proximity to the
diaphragm E and is fitted to slide or move freely relatively thereto. The said sliding
or movable diaphragm E is attached by means of extensions E4 passing through
slots A³ in the telescope A¹ to a ring E' which is preferably oval and formed some-
what larger than the said tube A' so as to be capable of a certain amount of movement
thereon. The said ring E is hinged or jointed at Es to one extremity of an arm N
hinged or jointed at N' to the telescope A³ or to a ring or reinforce thereon and
"having a curved or slanting groove N (similar to the groove K' in the strip or
piece K) in which is adapted to engage the pin or projection H2 upon the slide block
or plate H. When the arrow upon the vernier scale H³ on the slide block or plate H
points to zero on the graduated scale A² the cross wires or hairs E³ on the sliding or
movable diaphragm E coincide with and are directly in line with the cross wires or
hairs E upon the fixed diaphragm E (as shown in Figure 5). By moving the said
slide block or plate H away from the eye piece of the telescope A' and towards the
object glass thereof the said sliding or movable diaphragm E can be operated or
adjusted so as to move the latter and the cross wires or liairs E3 thereon away from
the cross wires or bairs E' upon the fixed or stationary diaphragm E (as shown in
Figure 6) thus permitting the cross wires or hairs Es to be adjusted relatively to the
cross wifes or hairs E. The prismatic lens or object glass G is arranged in a short

page_text: length of tube A' fitted to rotate freely in the adjusting tube of the telescope, and
provided with a pin A' which engages in a slot A in the said tube thus permitting
the said tube A* and prismatic lens or object glass to be turned half round, for the
purpose hereinafter described.
On using this form of my apparatus the object the range of which it is desired
to ascertain is first sighted and accurately intersected by the cross wires or
hairs E' E which coincide or are directly in line with one another the arrow
upon the vernier scale H³ on the slide block or plate H standing opposite or
pointing to zero upon the graduated scale A. The short length of tube A is
turned half round, so as to reverse the object glass and the said object will then
appear refracted some distance to the right or left of the said cross wires. The
slide block or plate H is then moved away from the eye piece and towards the
object glass until the cross wires or hairs E³ of the sliding or movable diaphragm E³
intersect or nearly intersect the said object when the slide block or piece L is clamped
in position by means of the screw L² and the intersection is perfected by means of
the micrometer screw M as before. The distance can then be read off upon the
graduated scale A² by means of the vernier.
In some instances in the case of a single telescope I employ the arrangement
shown in Figure 7 which is more especially advantageous when the said telescope is
not fitted with a tripod or stand. GG are prismatic shaped glasses or lenses which
are preferably formed by cutting one prismatic shaped lens horizontally and reversing
the two halves or parts so that the part G will refract one half or portion of the
object to the right and the part G¹ will refract the other half of the object to the
left as shown.
The object is then sighted and the refracted image of part of the said object
upon one half or part of the said compound lens G G intersected by the wire E¹
upon the fixed diaphragm which is placed vertically in this instance and the
wire E (also placed vertically) upon the movable diaphragm E2 is adjusted by
means of the slide block or plate H and micrometer screw until it intersects the
refracted image of the part of the object upon the other half or part of the lens.
The distance or range is then read on the graduated scale A² as before. In
Figure 7 the cross wire E' on the fixed diaphragm is shown intersecting the
refracted image of the object upon the half or part of the lens, and the wire ³
upon the sliding or movable diaphragm is shown in chain lines adjusted so as to
intersect the image of the object upon the half or part G of the lens.
Figures 8, 9 and 10 illustrate a modification wherein I form the scale A2 upon the
tube of the telescope or upon one of the guide strips or pieces J' and I employ a
ring or collar a arranged to slide stiffly on the said tube by means of a spring bor
otherwise the entire length of the said scale and having a suitable external screw-
thread a adapted to engage with a corresponding internal screw-thread upon a
milled or roughened collar c. The milled collar c is connected with a vernier plate H
by means of a pin or projection d on the latter working in a circumferential groove ²
in the collar c or in any other suitable manner, so as to move or adjust the vernier
plate relatively to the said scale when the said ring or collar is turned. The said
vernier plate is connected by means of an extension H with the bar or rod N of
the movable diaphragın E², the said bar in this instance being fitted in a groove or
recess in the tube of the telescope, and pivoted at N* thereto. a² a² are guide pieces
firmly secured to or formed on the sliding collar a, and A are guides or strips firmly
secured to or formed on the tabe A of the telescope so as to permit the said collar to
slide freely laterally upon the said tube A but prevent its turning thereon.
In some instances Immount the lenses of each telescope of the double telescopes or
binocular in a suitable case or short tube e (as shown in Figures 11 and 12) arranged
to slide inside the tube, of the said telescope. e' is a rack provided upon the said
tube or case e, and is a pinion gearing therewith and firmly secured to or formed
on the stem or spindle g¹ of a hand wheel g supported in a suitable bearing in the
tube A of the telescope. By rotating the said hand wheel g the tube or case e can

page_text: be adjusted towards or away from the object glass through the said pinion f and
rack are strips or guide pieces firmly secured to or formed on the case or
tube e adapted to engage with suitable guides A* firmly secured to or formed on the
tube A and prevent any rotary movement of the case or tube e whilst permitting the
longitudinal movement thereof. Any other suitable means however may be employed
for adjusting the inside sliding caso or tube e carrying the said lenses relatively to the
object glass, for obtaining the right focus, without moving the said object glass or
lengthening the said telescopes, thus obviating the slight error that otherwise occurs
when the length of the outer tubes of the telescopes containing the prismatic object
glass or lens is increased to any appreciable extent and the angular adjustment of the
latter relatively to the other or fixed telescope effected.
A range finder constructed in the manner hereinbefore described enables ranges or
distances to be measured or ascertained with great accuracy and expedition, and the
said apparatus is simple and easily handled.
Figures 13 and 14 illustrate a device for enabling a tripod stand or support for my
improved range finder to be formed out of three or other suitable number of rifles.
O is a head attached to the underside of the telescope and having a swivel universal
or other suitable joint 01. 02 is a set screw for locking, securing, or clamping the
telescope A in position when adjusted. 003 are legs hinged or jointed at 0₁ to the
head O and forming as it were a short tripod. The said legs 03 are inserted into
the muzzles of the rifles as shewn by the chain lines in the drawing (Figures 13
and 14) which thus form continuations or prolongations of the legs of the said tripod,
and support the said telescope at a convenient height for use. The legs are
preferably formed of two or more diameters as shown so as to enable them to fit the
bore of rifles or guns of different calibres. This device is very convenient for military
purposes as it can be folded into a very small compass for transport and enables a
full sized tripod, stand or support to be provided for the range finder in a very
short time.
Moreover, although I have hereinbefore described convenient and advantageous
methods of carrying my said invention into practice it is obvious that I can somewhat
further modify the construction of my improved range finder without departing from
the nature of my said invention. For instance when two telescopes are used both
the said telescopes may be provided with prismatic shaped glasses or lenses. The said
telescopes or one of them may be fitted with a sliding or movable diaphragm similar
to that described with reference to the single telescope.
The prismatic glasses or lenses are bevelled to the angle best suited for the range for
which they are intended, and are either formed solid, part liquid, or composed of two
or more lenses, loose or connected together.
One or more of the prismatic glasses or lenses may be employed in each telescope.
The strips or pieces forming the slides for the block or plate with the vernier scale
may be countersunk or arranged in slots provided in the outer tube of the telescope
or telescopes and the micrometer and clamping screw so arranged as to enable the
range finder to be more conveniently packed in a smaller case and thus render it more
convenient for transport.
Having now particularly described and ascertained the nature of my said inven-
tion and in what matter the same is to be performed I declare that what I
claim is
First. The improved method of measuring or ascertaining distances by the aid of
the refraction of lightain passing through prismatic lenses substantially as hereinbefore
described.
Second. A range finder comprising two telescopes so connected that they are
capable of angular adjustment relatively to each other and provided with one or more
prismatic lenses, for the purpose above specified.
Third. A range finder comprising two telescopes either or both of which are pro-
vided with one or more lenses and diaphragms having cross wires or hairs and which

page_text: are hinged or jointed together and are provided with suitable means, effecting the
angular adjustment of one telescope and for ascertaining the amount of such adjust-
ment, substantially as and for the purposes set forth.
Fourth. The improved range finder constructed substantially as described with
reference to Figures 1 to 3 of the accompanying drawing and operating as and for the
purposes herein before specified.
'
Fifth. The modification of my said invention wherein I employ a single telescope
substantially as described with reference to Figures 4, 5 and or to Figure 7 or to
Figures S, 9 and 10 of the accompanying drawings.
Sixth. The improved means for moving or adjusting the lenses relatively to the
object glass, substantially as described with reference to Figures 11 and 12 of the
accompanying drawings for the purpose above specified.
Seventh. The improved devico for forming a tripod stand or support constructed
substantially as described with reference to Figures 13 and 14 of the accompanying
drawings.
Dated this 23rd day of June 1890.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.