Improvements in and relating to Theodolites and like Instruments.
Year: 1897

page_text: Date of Application, 5th Oct., 1897-Accepted, 11th Dec., 1897
COMPLETE SPECIFICATION.
Improvements in and relating to Theodolites and like Instruments.
We, MARTIN LEITHOFF and ADOLPH HEIN, both of Hagen, Westphalia, in the
Empire of Germany. do hereby declare the nature of this invention und in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:―
This invention relates to that class of instruments used by Surveyors for level- .
ling and the like, and its object is to provide a simple and rapid adjustment of the
telescope and appurtenances in a true position previous to use.
This invention consists in providing, an attachment, between the tripod stand
and the telescope and level adjustments, in such a manner that a pendulum
weight falling below the centre of gravity of the telescope and appurtenances
automatically brings them to a level in any position.
One mode of carrying this invention into effect is illustrated in the accompany.
ing sheet of drawings as follows,-
Figure 1 represents the telescope and pendulum in elevation with a portion of
the tripod stand.
Figure 2 is a part vertical section through the automatic adjusting device.
The telescope k and the air level with the usual appurtenances are mounted upon
a spherical section piece a. This spherical section piece a has attached to it a
ring c and a downwardly projecting extension upon which a weight S screwed or
fixed to it is placed. The spherical section piece is hollow and arranged in such
a manner underneath, that a rib f passes through it as shown in Figure 2, and is
attached to a cylindrical piece g which again is attached in turn to the head of the
tripod h. Upon the rib f a steel or suitable centre point e is fixed which projects
into a corresponding recess or centre & formed in an extension inside the spherical
section piece, and thus the pendulum weight and the telescope and appurtenances
are all suspended upon this centre piece e and the weight of the pendulum is so
proportioned that the centre of gravity of the whole arrangement falls underneath
the point of suspension.
The top end of the cylinder g is screwed with a fine thread and fixed upon it is
a sheath or cap i whose upper portion forms a circular ring embracing the spherical
section piece a as shown.
It is evident from the hereinbefore described construction, that when the
theodolite is in use and placed in a new position, that by releasing the cap i the
pendulum swings the telescope and appurtenances at once into a true vertical
position, then by screwing down the cap i that position is secured and the usual.
operations of survey and levelling can be performed,
It is clearly to be understood that the particular formation of the spherical
section piece and its attachment to the tripod can be varied in many ways without
departing from the subject of the present invention.

page_text: Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is,-
1. In theodolites and like levelling instruments the provision of a spherical
section piece mounted at its lower side upon a steel or other suitable centre and
carrying an extension pendulum and weight in such a manner that when the
theodolite is mounted upon the top of the spherical section piece, the centre of
gravity of the whole arrangement falls below the point of suspension; the whole
as a means for rapidly and accurately setting the level of the theodolite previous
to the usual observations.
2. The improvements in and relating to theodolites herein before described with
reference to Figures 1 and 2 of the drawings.
SIL
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.