Improvements in Apparatus for Measuring Strains or Forces.
Year: 1890

page_text: Date of Application, 14th May, 1890
Complete Specification Left, 13th Feb., 1891-Accepted, 14th Mar., 1891
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Measuring Strains or Forces.
I, WILHELM DRUCKENBRODT, of Schoneberg, Berlin, in the Empire of
Germany, Gentleman, do hereby declare the nature of this invention to be as
follows:-
My invention for improvements in apparatus for measuring strains or forces has
for its object to provide improved means for measuring the extension or compression
of a bar or tube which is subjected to the strain or force to be measured, and
consists essentially in rigidly connecting to the two ends of the said bar or tube
two plates and in enclosing the space between them and filling it with a suitable
liquid and connecting it to a graduated indicating tube.
Dated this 14th day of May 1890.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Measuring Strains or Forces.
I, WILHELM DRUCKENBRODT, of Schoneberg, Berlin, in the Empire of
Germany, Gentleman, 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 for improvements in apparatus for measuring strains or forces has
for its object to provide improved means for measuring the tension or compression
of a bar or tube which is subjected to the strain or force to be measured, and
consists in rigidly connecting together at one end a bar and tube, while the bar-
or a disc or piston-on its other end fits in the said tube which is provided with a
diaphram or end cover, thus forming a chamber between the end of the tube and
the end of the bar, which is filled with liquid and connected to a graduated tube, so
that, on the application of a strain or force to the apparatus in the direction of its
axis elongation or contraction results, which increases or diminishes the volume of
the liquid in the aforesaid chamber, such variation being indicated by the rise or
fall of the liquid in the beforementioned graduated tube which thereby measures
the magnitude of the force applied.
In the accompanying sheet of illustrative drawings,
Fig. 1 represents an arrangement of apparatus in which a metallic bar a is
rigidly secured to the tube d, its other end forming a disc or piston / which fits in
the tube d provided with a diaphram c through which the bar a passes. A chamber
is thus formed between the piston and diaphram c, which is filled with any
suitable liquid and connected to a graduated tube e. On the application of an
external force in the direction of the axis of the apparatus the bar a is elongated
or contracted; the volume of the enclosed liquid being correspondingly increased
or diminished such variation being indicated by the height of the liquid in the
tube e the graduations on which are determined tentatively by the application of
known forces. Instead of the bar a, a tube may be substituted if preferred.
Fig. 2 represents a vertical section of a modified arrangement in which the force
is measured by the elastic resistance of the tube a, the rod d and piston e replacing
the tube and diaphram in Fig. 1.
Fig. 3 represents a vertical section of an arrangement similar to that shown
in Fig. 2, the rod and piston being replaced by the solid plunger c c c¹ c¹.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
;-
1. An apparatus for measuring strains or forces by means of variations in the
length of a metallic bar, such variations being indicated by the variation in the
capacity of a chamber formed between a diaphram or plate rigidly fixed to one end
of the bar or tube subjected to the strain to be measured, and of a plate or
diaphram rigidly connected to the other end of the bar or tube, the said chamber
being filled with a suitable liquid and connected to a graduated indicating tube.
2. The arrangement and construction of apparatus for measuring strains or
forces substantially as described with reference to the drawings.
Dated this 13th day of February 1890
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.