Improvements relating to Levelling-staves.
Year: 1892

page_text: Date of Application, 5th Nov., 1892-Accepted, 31st Dec., 1892
COMPLETE SINIFICATION,
Improvements relating to Levelling-staves.
We, HENRY JAMES SPRATT, ALFRED SIDNEY SPRATT and GEORGE ALBERT
SPRATT of Tudor Works, Tudor Road, Hackney, in the County of London,
Manufacturers, 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 :-
Our invention relates to improvements in levelling-staves.
The object of our said invention is to construct an improved levelling-staff in
which the customary scales or graduations, marked upon suitable material, are
applied to the staff in such a manner that they can be readily removed therefrom at
any moment, and can be replaced thereon with equal readiness.
In order that our invention may be clearly understood we will now proceed to
describe the same with reference to the accompanying drawings, in which
Figure is a perspective view of a levelling-staff constructed according to our
invention.
Figure 2 is a view of a portion of the said staff showing a transverse section of
the same in a plane at right angles to the length of the staff.
Figure 3 is a section through the upper portion of the staff, from front to back, in
a plane parallel to its axis, and
Figure 4 is an exterior view of the said upper end of the staff.
A, A', A' are the three sections of the staff. The two inner sections are adapted
to move in and out telescopically in the usual manner.
B B are grooves or rebates, formed in the sides of each section of the staff just
above the face of the staff and in the parts of the side walls which project beyond
the said face. C is a piece or strip of xylonite or celluloid, prepared paper, metal
or any other suitable material which has the scales or graduations marked thereon
by any suitable means.
D is a metal shoe which is placed upon the lower end of the section A to protect
the same and to close the lower ends of the grooves or rebates B therein.
The edges of the said pieces or strips C are placed in the grooves or rebates B,
or under overlapping portions of the staff, so that the pieces or strips are securely
retained in place thereby. Any convenient additional means may be employed if
desired to assist in retaining the said pieces or strips in place.
The said pieces or strips C may be withdrawn and replaced, or other pieces or
strips substituted therefor, with but a slight loss of time, and without any such
troublesome manipulation as is needed when the scales or graduations as ordinarily
applied need repair or renewal.
The strips or pieces C are preferably made of material that is washable, so that
if soiled in the field they may be washed; the leveller is thus able to keep his staff
in a condition in which it may be read with ease and certainty.
The operation of removing and replacing these detachable faces being easily and
quickly effected, more than one series of pieces or strips with graduations thereon
may be kept on hand and inserted in place in the staff when needed. Or both sides
of each strip may be graduated so that it would only be necessary to withdraw and
turn the same to produce the fresh series of readings required.
We do not limit ourselves to the employment, for the said removable scales, of
the particular materials hereinbefore referred to; any suitable material may be
used provided always that the ready detachability of the scales from the staff is
ensured in the manner herein before explained. Nor do we confine ourselves to the
employment of the particular mode of securing the strips herein before explained.

page_text: 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 :-
First. Providing a levelling-staff with a scale or scales mounted in grooves
therein, or otherwise secured thereto so as to be readily attachable and detachable,
substantially as described for the purpose specified.
Second. A levelling staff constructed substantially as hereinbefore described with
reference to the accompanying drawings.
Dated this 5th day of November 1892.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicants.