IMPROVEMENTS IN INSTRUMENTS FOR MEASURING ANGLES
Year: 1875

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine;
Lake, & Co., Patent Agents, Southampton Buildings, London, for
the Invention of "IMPROVEMENTS IN INSTRUMENTS FOR MEASURING
ANGLES."—A communication from abroad by Rudolf Schneider, of
Segen Gottes, near Rossitz, Moravia, and Frederick William Kraft;
of Vienna, both in the Empire of Austria.
PROVISIONAL SPECIFICATION left by the said William Robert Lake
at the Office of the Commissioners of Patents, with his Petition,
on the 11th September 1875.
I, WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co.,
Patent Agents, Southampton Buildings, London, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN INSTRUMENTS FOR
MEASURING ANGLES," a communication, to be as follows:-
These improvements relate to surveying instruments, and more
especially to instruments to be used in mining surveys for measuring
angles. The construction of these instruments is such as to render the
use of a compass unnecessary, thereby obviating all the difficulties and
delays arising from the deviation and variation of the compass needle,

page_text: and enabling the measurements to be made more accurately and quickly
than heretofore.
The apparatus herein described consists of two exactly similar instru-
ments which are to be suspended separately on two separate stretched
cords, and are connected preferably by means of a horse-shoe magnet
attached to the one and a steel plate attached to the other instrument.
Each of these twin instruments consists of a graduated disc, divided
into 360 or 400 degrees. This graduated disc is screwed to a plate fixed
-to-the-lower-part-of-a-bent_carrier. The upper part of this carrier is
provided with a round plate, on which a double armed bracket is
screwed vertically and in a central position to the graduated disc. The
bracket is provided at its upper end with a box head, through which a
prismatic bar passes vertically, and this bar is toothed along its entire
length, so that it can be fixed at any point by means of a thumb screw.
The box head is also provided with a pinion, the teeth of which gear
into the teeth of the prismatic bar. By turning this pinion the relative
position of this rack to the bracket can be varied at will. The rack has
at one end a forked head carrying a cross arm which works on a pin in
the fork, and is provided with a suspension hook at each end. By means
of these hooks the instrument. can be suspended, either directly from
the cord or indirectly from an intermediate suspension rail hung to the
cord. In the centre of the graduated disc a steel screw is fitted, forming
a pivot socket, and opposite to this screw in the upper part of the
carrier a steel pin with conical socket is fixed. These two sockets form
-the bearings for the pivot pin, to which a plate (alidade) carrying the
verniers is firmly attached. On this pivot pin the arm turns which
forms the means for connecting the one instrument with its twin
instrument. This connecting arm consists of two parts of equal length.
The shorter part is provided with a weight in order to counterbalance
the longer part. This longer part carries at its free end either a smooth
magnetised steel plate or a horse-shoe magnet with smooth contact
surfaces, the one of the twin instruments being provided with the steel
-plate_and_the_other with the magnets. The vertical contact surfaces of
the plate-and-the-magnet-are-arranged. so as to be in the same plane as

page_text: By means of an adjusting screw fixed to the said turning plate
(alidade), the arm can be slightly turned for the purpose of adjusting
its position to the cross direction of the verniers. A spring fixed on the
other side, opposite to the adjusting screw, affords the necessary counter-
pressure.
When in use, each instrument is suspended by its hooks from an
intermediate suspension rail hung to the cord. This suspension rail is
provided. with two hooks to be attached to the cord, and carries between
two shoulders a wire which can be stretched by suitable nuts. Each
instrument is hooked to the wire of each suspension rail, the length of
which being preferably about three feet or more than five times that of
the space between the suspension hooks of the instrument, it serves as
means for obviating errors arising from the irregularities of the suspension
cord. On account of the movable joints, formed by the cross arm on
the suspension wire and by the hooks and bracket pin, the weight of
the graduated plate is alone sufficient to ensure its horizontal position.
These movable joints might evidently be also obtained by the use of
knife edges or pivot points instead of a pivot pin and hooks.
The above described arrangement of the adjustable rack is necessary
in order to enable the twin instruments to be brought into the same
horizontal plane, should the suspension cords have to be fixed at
different heights. Whatever angle is formed by the two suspension
cords will be indicated by the graduated plates and verniers of the two
instruments hanging from the cords, as the plates (alidados) carrying
the verniers and connected as described turn on the fixed graduated
plates differently, according to the relative positions of the two instru-
ments to each other.
SPÉCIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Robert Lake in the Great Seal Patent
Office on the 10th March 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, [, WILLIAM
ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London, send greeting...

page_text: }
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of September, in the
year of our Lord One thousand eight hundred and seventy-five, in the
thirty-ninth year of Her reign, did, for Herself, Her heirs and successors,
give and grant, unto me, the said William Robert Lake, Her special
licence that I, the said William Robert Lake, my executors, adminis-
trators, and assigns, or such others as I, the said William Robert
Lake; my executors, administrators, and assigns, should at any time
agree-with-and-no others, from time to time and at all times there-
after during the term therein expressed, should-and-lawfully-might-
make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN INSTRUMENTS FOR MEASURING ANGLES," a
communication to me from abroad by Rudolph Schneider, of Segen
Gottės, near Rossitz, Moravia, and Frederick William Kraft, of Vienna,
both in the Empire of Austria, upon the condition (amongst others) that
I, the said William Robert Lake, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
1
"'
NOW KNOW YE, that I, the said William Robert Lake, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the accompanying
Drawing forming a part of this Specification:
1
These improvements relate to surveying instruments, and more
especially to instruments to be used in mining surveys for measuring.
angles. Their construction is such as to render the use of a compass
unnecessary, thereby obviating all the difficulties and delays arising
from the deviation and variation of the compass needle, and enabling
the measurement-to-be-made-more accurately and quickly.
The said apparatus consists of two exactly similar instruments, which
arė to be suspended separately on two stretched cords, and are connected
preferably by means of a horse-shoe magnet attached to the one and a
steel plate attached to the other instrument.

page_text: Figure 1 is an elevation of my complete apparatus; and Figure 2 is a
plan of the said apparatus without the suspension parts. Both Figures
are drawn to a scale of two-thirds the full size.
.
Figure 3 shows a suspension rail drawn to a scale of one half the full
size.
Each of the twin instruments consists of a graduated disc a, divided
as usual into 360 or 400 degrees. This graduated disc is screwed to a
plate b, fixed to the lower part of a bent carrier B. The upper part of
this carrier B is provided with a round plate d, on which a double armed
bracket C is screwed vertically and in a central position to the graduated
disc a.
The bracket C is provided at its upper end with a box head ƒ,
through which a prismatic bar E passes vertically, and this bar is
toothed along its entire length, so that it can be fixed at any point by
means of a thumb screw 9. The box head is also provided with a
pinion c, the teeth of which gear into the teeth of the prismatic bar E.
By turning this pinion the relative positions of the prismatic bar E to
the bracket C can be varied at will. The prismatic bar E is provided
at one end with a forked head h, carrying a cross bar D, which works
on a pin i in the fork h, and is provided with a suspension hook e', e²,
at each end. By means of these hooks the instrument can be suspended
either directly from the cord or indirectly from an intermediate sus-
pension rail F hung on the cord. In the centre of the graduated disc a
a screw q is fitted, forming a pivot socket, and opposite to this screw in'
the upper part d of the carrier a pin 8 with conical socket is fixed.'
These two sockets form the bearings for the pivot pin 7, to which a plate
carrying the verniers x, y, is firmly attached. On this pivot pin / the
arm n turns, which forms the means of connecting the one instrument'
with its "twin instrument. This connecting arm consists of two'
parts n', n², of unequal length: The shorter part n' is provided with a
weight to counterbalance the longer part n²: This longer part n³ carries
at its free end either a smooth magnetized steel plate k or a horse-shoe:
magnet with smooth contact surfaces, the one of the twin instruments:
being provided with the steel plate, and the other with the magnet.>
The vertical contact surfaces of the plate and the magnet are arranged,
so as to be in the same. plane. as the axis of the plate carrying the
"

page_text: The turning plate m covers the entire graduated plate except at two
places where it is cut away and carries two verniers x, y.
By means of an adjusting screw o fixed to the turning plate m the
arm n can be slightly turned, for the purpose of adjusting its position
to the cross direction of the verniers x and y. A spring r, fixed on
the other side opposite to the adjusting screw, affords the necessary
counterpressure.
=
When-in-use each instrument is suspended by its hooks from an
intermediate suspension rail-hung on the cord. This suspension rail is
provided with two hooks to be attached to the cord, and carries between
two shoulders a wire t; which can be stretched by suitable nuts. The
instrument is hooked to the wire of the suspension rail, the length of
which being preferably about three feet, or more than five times that
of the space between the suspension hooks of the instrument itself,
serves as a means for obviating errors arising from irregularities of the
suspension cord. On account of the moveable joints formed by the
pin i and by the hooks'e', e², the weight of the graduated plate is alone
sufficient to ensure its horizontal position. These movable joints might
evidently be also obtained by the use of knife edges or pivot points
instead of a pivot pin and hooks.
The above-described arrangement of the adjustable rack and bracket
is necessary, in order to enable the twin instruments to be brought into
the same horizontal plane should the suspension cords have to be fixed
at different heights. Whatever angle is formed by the suspension cord
or cords it will be indicated by the graduated plates and verniers of the
two instruments hanging from the cords, as the plates (alhidades)
carrying the verniers and connected together as described turn
differently on the fixed graduated plates, and therefore indicate different
degrees according to the different relative positions of the two instru-
ments to each other.
The angle 2 + 4 formed by the two cord parts or cords S, S¹, and
∙S,_S',_will_therefore be equal to the angle 1+ 3. In_the_instance-
shewn-in-the-Drawing, the-angle-1-is-27%, degrees and the angle 3 62%
degrees, therefore the angle formed by the cord is 90 degrees.
It is evident that the two cords S, S¹, and S, S³, may consist either of
one single length stretched round a hook at the point S, or of two
lengths crossing each other.

page_text: Having thus fully described the said Invention as communicated to
me by my foreign correspondents, and the manner of performing the
same, I wish it understood that I claim,―
First. An instrument for measuring angles without the use of a
compass, and consisting of two twin instruments, each to be suspended
separately and, the vernier plates of which are connected by projecting
arms, substantially as described and for the purpose set forth.
-
Second. The combination of the carrier B, graduated plate a, pivoted
vernier plate and turning connecting arm n', n², substantially as
described and for the purpose set forth.
Third. The connecting arms with horse-shoe magnet z and magnetized
plate k, substantially as described and for the purpose set forth.
Fourth. The swinging suspension arrangement, consisting of the
fork h, pin i, cross bar D, hooks e', e³, or their equivalents, in com-
bination with the suspension rail F or its equivalent, substantially as
described and for the purpose set forth.
Fifth. The arrangement for adjusting the level of each instrument,
and consisting of the rack E, pinion c, and fixing screws g, or their
equivalents, substantially as described and for the purpose set forth.
Sixth. The suspension rail F, substantially as described and for the
purpose set forth.
In witness whereof I, the said William Robert Lake, have here-
unto set my hand and seal, this Tenth day of March, in the
year of our Lord One thousand eight hundred and seventy-six.
Witness,
HY. JA. NOONE.
W. ROB™. LAKE. (L.S.)