Improvements in Depression Range Finders.
Year: 1899

page_text: PROVISIONAL SPECIFICAL
Improvements in Depression Range Finders.
I, ROWLAND BROTHERHOOD, of 100, Belgrave Road, Oldham, in the County of
Lancashire, Civil Engineer, do hereby declare the nature of this invention to be
as follows:-
--
The object of my invention is to provide means for rapidly and accurately
ascertaining the range of moving objects from any position having a higher
level than the object the distance of which is required to be known and is
specially suitable for all elevated stations particularly fortresses on the sea coast
and to carry my invention into effect I construct my improved range finder as
follows:-
I provide a suitable stand or base which may be of wood and metal if port-
ability is required but for all fixed positions I prefer to use a stone or concrete
pillar let into the ground upon a suitable foundation. Upon top of the stand
I attach a circular metal disc which carries a male centre this is bolted to the stand
by bolts and has a piece of thick sheet rubber or other pliable material inserted
between it and the top of the stand so that it may bed firmly and allow of a
small amount of adjustment by means of tightening more or less the holding
down bolts, this disc may be provided with cross levels or a separate hand level
may be used upon it, for the purpose of ascertaining that the disc is perfectly
horizontal and its projecting centre truly vertical.
Upon this disc and centre a revolving frame is fitted which preferably has a
base plate about two feet six inches long or other convenient length this base
plate is enlarged in the centre part to the same diameter as the plate carrying
the male centre and rests upon it and is provided with a female centre fitting
the male centre of the lower plate. This enlarged central part may be cut with
teeth all round and have a worm gearing into it attached to the lower plate
made to throw in and out of gear so that the frame may be freely revolved when
the worm is out of gear and slowly moved by a worm wheel when in gear.
At each end of the revolving base plate uprights are attached the height of
which is adapted according to the position of the station and distance to be
read about a foot being a convenient height for most positions. One of these
uprights is made to carry a pair of telescopes which are mounted upon one pair
of trunions so that they are always in line with each other, and one of these
telescopes is provided with a spirit level adjusted to the line of collimation of
the telescopes.
Both telescopes are provided with a pointer in their diaphragms and a clamp
and tangent arm is fitted to the trunions for quick and fine adjustment.
One of the telescopes is a fairly large size and is preferably set to solar focus
the other a small telescope set to read at two feet six inches if the uprights are
The second or opposite up-
that distance apart, or whatever length they are.
right attached to the revolving base is arranged with an opening to permit a
clear field of view from the large telescope on the opposite upright and at the
side of this opening a tangent scale is attached by suitable clips for rapid affix-

page_text: ing and removal. This tangent scale is read by the small telescope on the
opposite upright and is fixed with its zero to read on the line of collimation of the
telescopes when the level is in the centre of its run. The tangent scale is marked
off according to height of the position at which the instrument is used this height
forms the base, the line of sight through the telescope the hypothen use and this
angle being read on the scale by the small telescope gives the length of the
hypothenuse which is the range required, so that in ascertaining a range all that
has to be done is to sight the object through the large telescope with one eye
and read the distance through the small telescope with the other eye the tele-
scopes being fixed a suitable distance apart in the trunions to allow of this
being done.
In following moving objects such as a vessel at sea the movements would
be more conveniently and accurately followed by means of the tangent arm
actuating the fine movement of the telescopes and worm wheel for the fine move-
ment of the base.
It will be seen that the same instrument will do for any position within its
range the only part which would have to be altered is the tangent scale which
must be worked out and figured for every different height of base.
Dated this 26th day of June 1899
H. T. TALLACK,
Agent for Applicant, 10, Great Turnstile, Holborn, London, W.C.
I, ROWLAND BROTHERHOOD, of 100, Belgrave Road, Oldham, in the County of
Lancashire, Civil 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:-
The object of my invention is to provide means for rapidly and accurately
ascertaining the range of moving objects from any position having a higher
level than the object the distance of which is required to be known and is
specially suitable for all elevated stations particularly fortresses on the sea coast
and to carry my invention into effect I construct my improved range finder as
follows reference being made to the accompanying drawings of which Fig. 1
is a side elevation Fig. 2 a plan, Fig. 3 an end elevation taken from the
telescope end, Fig. 4 a view of the opposite upright facing the telescopes show-
ing the aperture for clearing the field of view of the large telescope and the scale
read by the small telescope similar letters denote corresponding parts through-
out the drawings.
I provide a suitable stand or base which may be of wood and metal if port-
ability is required but for all fixed positions I prefer to use a stone or concrete
pillar Alet into the ground upon a suitable foundation. Upon the top of the
stand I attach a circular metal disc B which carries a male centre shown in
dotted lines this is bolted to the stand by bolts and has a piece of thick sheet
rubber or other pliable material inserted between it and the top of the stand
so that it may bed firmly and allow of a small amount of adjustment by means
of tightening more or less the holding down bolts, this disc may be provided
with cross levels or a separate hand level may be used upon it, for the purpose of
ascertaining that the disc is perfectly horizontal and its projecting centre truly
vertical,

page_text: Upon this disc and centre a revolving frame is fitted which preferably has a
ase plate about two feet six inches long or other convenient length this base
late is enlarged in the centre part D to the same diameter as the plate carrying
he male centre and rests upon it and is provided with a female centre E fitting
he male centre of the lower plate. This enlarged central part may be cut with
eeth all round and have a worm gearing into it attached to the lower plate
made to throw in and out of gear so that the frame may be freely revolved when
the worm is out of gear and slowly moved by a worm wheel when in gear or the
lower plate may carry the teeth and the worm wheel be attached to a bar pivotted
to the underpart of the base plate shown at F so that it may be pulled out of
gear for quick movement and it is held in gear by means of a spring for slow
adjustment.
At each end of the revolving base plate uprights G and H are attached the
height of which is adapted according to the position of the station and distance
to be read, about a foot being a convenient height for most positions. One of
these uprights G is made to carry a pair of telescopes I and J which are mounted
upon one pair of trunions so that they are always in line with each other, and
one of these telescopes I is provided with a spirit level K adjusted to the line of
collimation of the telescopes.
Both telescopes are provided with a pointer in their diaphragms and a clamp
and tangent arm L is fitted to the trunions for quick and fine adjustment.
One of the telescopes I is of fairly large size and is preferably set to solar
focus the other Ja small telescope set to read at two feet six inches if the up-
The second or
rights are that distance apart or whatever length they are.
The
opposite upright H attached to the revolving base is arranged with an opening M
to permit a clear field of view from the large telescope on the opposite upright
and at the side of this opening a tangent scale N is attached by suitable clips
for rapid affixing and removal. This tangent scale is preferably attached to a
sliding bar fitted with a short rack and pinion to allow of slight adjustment
for bringing the scale rapidly to exact position and is read by the small tele-
scope J on the opposite upright G it is set with its zero to read on the line of
collimation of the telescopes when the level K is in the centre of its run.
level being adjusted so that the line of collimation of the telescopes is- truly
horizontal when the bubble is central. The tangent scale N is marked off accord-
ing to height of the position at which the instrument is used, this height forms
the base, the line of collimation through the telescope the hypothenuse and this
angle being read on the scale N by the small telescope J gives the length of the
hypothenuse which is the range required, so that in ascertaining a range all that
has to be done is to sight the object through the large telescope I with one
eye and read the distance through the small telescope J with the other eye the
telescopes being fixed a suitable distance apart in the trunions to allow of this
being done.
In following moving objects such as a vessel at sea the movements would be
more conveniently and accurately followed by means of the tangent arm L
5 actuating the fine movement of the telescopes and the worm wheel F for the fine.
movement of the base plate.
50
It will be seen that the same instrument will do for any position within its
range the only part which would have to be altered is the tangent scale which
must be worked out and figured for every different height of base.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. The use in combination with depression range finders of a revolving frame C
carrying uprights G and H mounted upon a centre B the said revolving frame
65 carrying twin telescopes I and J and tangent scale N substantially as herein
described and illustrated in the accompanying drawings.

page_text: 2. The use in combination with depression range finders of a tangent scale
so divided and figured that the length of the hypothenuse is read off direct for
any height of base for which the tangent scale is calculated.
3. The use in combination with depression range finders of twin telescopes
mounted upon one trunion so that the line of collimation of both move together
one of the said telescopes being arranged to read a distant object and the other
a tangent scale divided to indicate the length of hypothenuse.
4. The improved depression range finders substantially as herein described and
illustrated in the accompanying drawings.
Dated this 25th day of Auril 1900
H. T. TALLACK,
Agent for Applicant, 10, Great Turnstile, Holborn, London, W.C.