Improvements in Measuring Instruments.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvements in Measuring Instruments.
I, GEORGE DARBEY of Cremona House, Perry Road Bristol in the County
of Gloucester Mechanician do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and asper-
ained in and by the following statement:-
My invention relates to improvements in measuring instruments, whereby
diameters of the strings of musical instruments may be measured in suitable terms
or wires or the like, each measurement being capable of the most delicate
adjustment.
In order that my invention may be clearly understood I have appended the
accompanying sheet of drawings in which
Figure 1 represents an elevation of the device or contrivance according to my
said invention and Figure 2 a sectional elevation thereof similar letters or figures
indicating corresponding parts in both views.
In carrying my invention into effect I employ a metal body B, internally screwed
with a thread of predetermined pitch, and having a flange or disc D formed upon
or attached to the base thereof. A plug or spindle A with a milled head A¹ is
screwed to perfectly correspond to the internal screw thread of the metal body B
and is furnished with a flange or disc E, corresponding to D which is fixed. A
zero mark or datum point is fixed when the plug or spindle A is sufficiently with-
drawn to cause the faces of D and E to be close together, in such a manner that
said zero or datum point is then opposite the zero of the scale marked upon the
circumference of E which, as hereinbefore mentioned may be of any character and
may be delineated in any terms applying to accurate linear dimension. One
revolution, therefore, of the plug or spindle A may be graduated in predetermined
measurements upon E, corresponding to the space between D and E, but in order
to increase the range of the instrument I form a number of rings or circular
marks a upon the plug or spindle A which may or may not be numbered or
marked. The edge of the body B therefore forms an index for the number of
revolutions of A, and the relative positions of D and E the fractional parts
thereof. In order to utilise the device as a fixed gauge, I use a set screw C
which holds the plug or spindle A in position wherever this may have been
placed.
Thus the distances between D and E may be micrometrically measured and
determined, in terms of the total revolutions of A by the marks a and fractionally
by the marked discs D and E.
I am according to my said invention enabled to construct a cheap and simple
micrometer gauge, especially adapted for the estimation and testing of the strings
of musical instruments, electric wires and like purposes, said instrument being
extremely simple and easily carried in the waistcoat pocket. In the case of using
it for the measurement of electric wires I prefer to arrange the scale in such a
manner that the standard wire gauge and the safe current to be carried may be
read off at the same time.
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
In a micrometer gauge the combination of a plug or spindle A with circular
marks a and scaled disc E. with a body B. disc D and set screw C, substantially

page_text: as and for the purposes herein set forth, with reference to the accompanying
drawings.
Dated this 8th day of May 1892.
FREDK. WALKER,
11, Furnival Street, Holborn, London, E.C., Agent for the Applicant.