Improvements in Instruments for Ascertaining Distances, applicable to Surveying and other Purposes.
Year: 1893

page_text: Date of Application, 4th May, 1893-Accepted, 2nd Sept., 1893
COMPLETE
SPECIFICATION.
Improvements in Instruments for Ascertaining Distances, applicable
to Surveying and other Purposes.
We, VICTOR VON ZIEGLER Engineer and CARL HAGER Electrical Engineer
both of Rollingergrund Luxemburg in the Empire of Germany, 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 instrument forming the subject of the present invention, called the
"Universal Tacheograph,' serves for surveying any kind of surface, such as
bridges, gardens, forests, mountains or hills and valleys. The instrument and its
working is hereinafter fully described.
The operator remains at the instrument during the whole time the observation is
being taken and is not required to cross over the crops in the fields or over gardens,
hedges and meadows or to cross any rivulets or to climb up mountains; neither is
it necessary to make use of the chain or rod or to construct or calculate any angles.
The instrument enables surveyings to be made in about a quarter the time required
with any of the instruments or methods hitherto in use and the finishing work at
the office is reduced to about one third in comparison with the ordinary methods.
At the same time the instrument assures practically absolutely true surveyings,
that is to say, that the surveyings done with it cannot be surpassed in exactitude
and errors are almost impossible. Only one assistant is required in connection
with this instrument.
The invention is represented in the accompanying drawings, in which :-
Figure 1 is a perspective view of the base plate of our apparatus showing the
graduated rule.
Figure 2 is a side view of our apparatus partly broken away and Figure 2t is
a view of part of the apparatus seen at right angles to Figure 2.
Figures 3 and 4 are views of various parts of our apparatus shown to a
larger scale.
Figure 5 is a view of a levelling staff, and
Figures 6 and 7 are diagrams showing the method of working the apparatus.
The "Universal Tacheograph," which is mounted, in the usual way, upon a
tripod stand and is capable of swivelling round, consists, firstly, of a circular table
and a flat measuring rule A B, see Figures 1 and 2, which is provided with a
levelling tube so as to level the rule to the horizontal. The rule is further
provided with graduations a. b. starting with zero at the centre of the pin z, which
pin forms the pivot of the instrument.
The said flat measuring rule forms the base upon which is mounted the real
distance finder, which forms the object of this invention. By means of this
instrument the horizontal distance of any desired point of the land to be surveyed
can be read off quickly and accurately from the point a at the centre of the vertical
measuring surface of the rule which latter is supported by and turns on the metal
ring at the outer edge of the circular table but does not touch the sheet of paper.
For the sake of clearness we will first proceed to explain the theory.
Suppose a line A¹ B', Figure 7, requires to be surveyed and having as its
horizontal projection the line A B. AN represents a geodetic telescope, which is
suspended at the point A and can turn in a vertical plane. The point A is in a
vertical line with the point A'. The longitudinal axis of the telescope passes
during its up and down movement over the vertical line V O. B C is a
levelling staff placed at the point to be measured with its zero point at the top
at p and graduated downwards. The telescope is now by means of a screw RS
Figures 2 and 2, directed to the zero point on the levelling staff in the direction

page_text: of the line A p. This having been done the telescope is turned round on its
point A (Figure 7) by means of the micrometer screw J, Figures 2 and 2bts so as
to be lowered to an amount V, & equal to Tb of A O. The axial line of the
telescope has naturally been lowered on the levelling staff to a corresponding
amount the centre of the cross lines being consequently directed to q p. q. is read off
and the following equation is obtained :-
we obtain the length A B = 100 p q
In order therefore to find the distance A B we have to multiply the height p g
read off by 100, which is done by simply moving the decimal point.
The instrument has, besides other details, a good telescope capable of turning
through a vertical plane on a centre o Figure 2, and being supported in the
carriers or forks P and Q connected to the supporting column of the telescope.
The telescope is provided with a supporting plate F resting on the knife edge U,
which arrangement enables the distance of the central or turning point o¹ from the
knife U, on which the telescope rests, to vary whilst the distance r. s. Figure 2
remains constant. The screw RS allows the telescope to be moved quickly into
any desired position, when, for instance, setting the telescope on the zero point on
the levelling staff.
The bearing of the telescope on the knife edge U can be raised or lowered by
means of the micrometer screw J, Figures 22 and 4, to any desired distance.
The head of this micrometer screw is provided with a drum J¹ bearing graduations
which can be read off from a fixed index hand I so as to show the extent and the
limit of the movement.
The levelling staff, Figure 5, to be used with this instrument has two adjoining
faces one being divided into divisions, of two centimeters and the other into
divisions of 5 and 10 centimeters.
After having placed the surveying instrument on the tripod stand in a horizontal
position, the micrometer screw J is turned with the zero point at the index hand and
the cross threads of the telescope directed through the medium of the screw
spindle R S to zero a on the levelling staff, Figure 5, which latter is erected at the
point from where the distance is to be ascertained. The micrometer screw is now
turned round till the number 2 comes in front of the index hand I, which causes
the telescope to be lowered to a known amount at the point where the plate F rests
on the knife edge U for example of the distance rs Figure 2 so that, for instance,
the cross threads of the telescope point to ẞ on the levelling staff. This length aẞ,
which in the present instance comprises 20 divisions or 40 centimeters corresponds to
40 meters linear distance on the horizontal line A. B Figure 7. In order to test
the correctness of this distance, the micrometer screw Jis turned further till it
indicates 4 under the index, thereby causing the telescope to make another equal
movement so that the reading on the levelling staff by means of the cross threads
gives double the length of the first reading, i.e., 80, which is a proof of the
correctness of the measurement. After this the point 40 on the rule a. 6 Figures 1
and 2, is marked on the drawing paper. The same operations are repeated for
each distance to be measured. The scale on the rule is usually 1 in 1000.
the cross threads had at the second reading pointed to say 79 or 82, it would mean
that an error had been committed through the incorrect setting of the instrument
through the micrometer screw and the operation should be recommenced from the
If

page_text: beginning. Although a mistake may not necessarily be made it is recommended
to test the correctness of the first measurement each time by a second measurement.
Figures 1 and 6 show the reproduction of the surveys of plots of land.
In order to survey a field A B C DEF (Figure 6) the operation is as follows:
A point o either in the field or outside it from which the greatest possible number of
points in the field can be seen is chosen for the instrument and the levelling staff is
fixed at A. After having taken the distance o A it is traced on the drawing paper
by means of the scale a. b on the sliding rule; a. a¹ representing that distance at
the reduced scale.
The staff is then moved to the point B and having measured o B the distance is
again marked to scale on the paper starting of course from centre o in the
direction o B; a. b being the distance to scale it remains only to connect the two
points marked on the paper by a line a¹ 6 which therefore represents the geodetic
survey of the line A B of the field.
The operation is repeated for each one of the points C D E F of the field which
reduced on the drawing give the plan a' b c d e f
By this instrument distances up to 200 metres can be taken providing the
telescope is suitable. The correctness of the measurements can easily be tested by
the separate use of the chain. When surveying rising or uneven land the
measurements with the instrument are far more correct than those with the chain
as the former gives the horizontal distance correctly which cannot be done with
the chain.
For distances of from 50 to 200 metres the divisions of two centimeters on the
levelling staff are used together with the divisions 2 and 4 on the drum of the
micrometer screw, while for distances of less than 50 metres the divisions of 5 and
10 centimeters on the levelling staff together with the divisions 5 and 10 on the
drum of the micrometer screw are used.
The latter arrangement has been adopted for the purpose of facilitating and
insuring correctness in connection with short distances.
The vertical travel of the micrometer screw or rather that of the knife edge in
connection with it corresponds to the line Vt Figure 7, and may be made to
equal 100, 30, 25, 30, 10 of A O Figure 7 which represents & Figure 2.
It will be understood that the instrument can also be used for levelling purposes.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. A distance finder for ascertaining horizontal distances by means of a levelling
staff arranged in such a manner that the distance between the instrument and the
levelling staff i.e. the horizontal distance to be ascertained is in the same proportion to
the height read on the levelling staff that the constant distance rs is to the amount V t
which the telescope has been lowered at the knife edge U by the micrometer screw
substantially as herein shown and described.
2. In distance finders of the type characterized in Claim 1, the arrangement of a
telescope and two screws (a quick threaded and a micrometer screw) which both
allow the instrument to be set at an angle which being read off on the levelling
staff gives a fraction of the horizontal distance to be ascertained.
3. In a distance finder as claimed in Claim 1 the rapid adjustment of the telescope
to the zero point of the levelling staff by means of a quick threaded screw S and
the adjustment of the inclination of the telescope by means of a micrometer screw J
in certain proportions to the distances substantially as herein shown and
described.
4. In connection with the distance finder as claimed in Claim 1, a part F resting
on a knife edge U for the purpose of controlling the telescope and enabling the
sight line to be raised or lowered substantially as herein shown and described and
for the purpose stated.

page_text: 5. In instruments for measuring distances the peculiar arrangements and
combinations of parts substantially as herein shown and described.
Dated this 4th day of May 1893.
VICTOR VON ZIEGLER,
CARL HAGER,
By Harris & Mills,
23, Southampton Buildings, London, W.C., Agents.