Improvements in the Traversing and Levelling Heads of Theodolites, or like Instruments.
Year: 1897

page_text: Date of Application, 18th June, 1897--Accepted, 14th Aug., 1897
COMPLETE SPECIFICATION.
Improvements in the Traversing and Levelling Heads of Theodolites,
or like Instruments.
We, ALEXANDER IRONSIDE LITTLEJOHN, of 85 Lambton Quay, in the City of
Wellington, New Zealand, Scientific Instrument Maker, and ARTHUR MARINUS
ALEXANDER STRUBEN, of 4, Albert Hall Mansions, Kensington Gore, in the County of
London, 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 :-
This invention relates to certain improvements in traversing and levelling heads of
the kind set forth in the Specification of a prior Patent No. 21195 of the year 1895
whereby the construction of such heads is considerably simplified.
According to our present invention the "clamping piece," that is to say the portion
of the head by which the traversing and levelling parts are clamped together after
being set in the required position, is constructed and arranged in the manner
hereinafter described so that the clamping is effected by a nut situated either at the
upper or the lower part thereof.
In order that our said invention may be fully understood aud readily carried into
effect we will proceed to describe the same with reference to the accompanying
drawings in which:
Figure 1 is a vertical section of a traversing and levelling head with our improved
clamping device applied thereto, and:
Figure 2 is a similar view shewing a modified construction of the clamping
device.
Figure 3, is an inverted plan of a cap-piece and :
Figure 4, is a plan of a washer, both of which parts are hereinafter more fully
referred to.
'
A is the cap-piece to which the legs are hinged in the usual manner, the said
cap-piece having a central aperture a¹ therein to permit the clamping piece B to freely
move horizontally in any desired direction. C is the spherically shaped traversing
head and D the correspondingly shaped levelling head which is capable of swivelling
or rocking about the traversing head in the manner set forth in the aforesaid prior
specification.
In the arrangement illustrated in Figure 1 the clamping piece B is formed in one
with the levelling head D and is funnel shaped, the tubular stem b thereof extending
through the aperture a' in the cap piece A and receiving a fly nut E.
The clamping
piece B may be formed separately from the levelling head D and of cylindrical or
other suitable form; and its stem b may be of solid instead of tubular form. The
said fly nut has a spherical end e which is formed in a piece with or separate from
the said nut and is adapted when said nut is tightened up, to bear against the
correspondingly shaped spherical opening in a plate or washer F constituting the
bottom traverser of the head. The theodolite or other instrument is carried by
the levelling head D in any suitable manner. d is an india-rubber ring which is
situated in an annular recess in the levelling head and serves as a buffer to lessen the
shock that might otherwise occur by the striking of the edge of the traversing head C

page_text: against the levelling head D. It will be seen that the fly nut E is situated at the
lower part of the head in a position where it can be readily reached by the user.
In the modified arrangement illustrated in Figure 2 the clamping piece B is
separate from the levelling head D. This piece B is shewn tubular in the drawing
but if desired it may be solid instead of tubular. It is formed at its lower end with
a spherical enlargement d' that engages with a corresponding spherical opening
in the washer F and its upper end is screw threaded to receive a nut E¹ which may
be similar in construction to the part termed the "capstan head in the aforesaid
prior specification and be operated in a similar manner by means of the lateral
lugs E2.
"
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 :
: -
A traversing and levelling head of the kind specified provided with a clamping
device constructed and arranged substantially as described with reference to either of
the constructions illustrated in the accompanying drawings.
ted this 17th day of June 1897.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.