Improvements in Plumb Levels and analogous Instruments.
Year: 1893

page_text: Date of Application, 22nd Feb., 1893
Complete Specification Left, 18th Nov., 1893-Accepted, 23rd Dec., 1893
PROVISIONAL SPECIFICATION.
Improvements in Plumb Levels and analogous Instruments.
I, JAMES ALLAN, of 5 Octavia Street, Port Glasgow, in the County of
Renfrew, North Britain, Engineer, do hereby declare the nature of this invention
to be as follows, that is to say:-
My said invention has for its object by an improved construction to make 'plumb
levels and analogous instruments yield plain indications of smaller deviations from
accuracy than existing instruments ordinarily used for the same purposes.
In carrying out my invention according to one modification suitable for engineers
and machine makers, I construct a casing preferably of metal or principally of
metal, to be used in a vertical position, with accurately parallel sides and with a
base accurately at right angles to the sides. Within the casing a weight is
suspended by two cords and is in a compartment at the lower part in which it can
move to either side to a limited extent. Just above the weight there is fixed on a
small bridge or bracket a pointed pin serving as a centre to a long index finger or
pointer extending upwards with its upper end in front of a graduated scale. The
pointer is fixed in a piece which is centered on the pointed pin and extends down
on each side thereof to a crosspiece which is below the pin, and which has extending
down from it a finger projecting into a socket in the top of the weight. The
pointer and the parts to which it is attached are made so that their centre of
gravity is as nearly as possible coincident with the point of the pin on which they
are centered. When the instrument is used, as for example in testing, whether
what should be vertical and horizontal surfaces are accurately so and at right
angles to each other, the weight will move to one side or the other if the parts
being tested are not accurate and by acting on the finger of the part to which the
pointer is attached will cause the pointer to move over the graduated scale to a
proportional extent but multiplied in the ratio, that the top of the pointer is more
distant from the centre than the finger acted on by the weight.
When the instrument is to be used chiefly as a level it may be made with an
extended base suitable for the particular use to be made of it.
The details of the apparatus are susceptible of variation to suit different
purposes, the principal feature being the method whereby the movement of the
weight is indicated on an enlarged scale. The weight may be suspended by two or
four cords or by fine wires.
Dated this Twenty-first day of February 1893.
EDMUND HUNT,
Applicant's Agent,
COMPLETE SPECIFICATION.
Improvements in Plumb Levels and analogous Instruments.
I, JAMES ALLAN, of 5 Octavia Street, Port Glasgow, in the County of
Renfrew, North Britain, 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, that is to say:-
My said invention has for its object, by an improved construction to make plumb
levels and analogous instruments yield plain indications of smaller deviations from
accuracy than existing instruments ordinarily used for the same purposes.

page_text: :
The details of my improved apparatus are susceptible of variation to suit
different purposes; but the principle feature of it is a method whereby the
movement of a suspended weight is indicated on an enlarged scale, whilst the
complete instrument is of moderate size and compact.
And in order that my said invention and the manner of performing the same may
be properly understood, I hereunto append a sheet of explanatory drawings to be
hereinafter referred to, and representing a modification of my improved instrument
suitable for engineers and machine makers.
Figure, 1, of the drawings, is a front elevation of the instrument; and Figures, 2,
and, 3, are vertical sectional views as at right angles to each other; whilst
Figure, 4, is an enlarged vertical section of a detail.
In these drawings the same reference letters are used to mark the same or like
parts wherever they are repeated.
The apparatus as shown in the drawing comprises a casing, A, preferably of metal,
or principally of metal, to be used in a vertical position, with accurately parallel
sides, B, C, and with a base, I), accurately at right angles to the sides. Within the
casing, a weight, E, is suspended by four cords, F, fixed at the top by passing through
holes, in the top, G, of the casing and being clamped, after adjustment, by small
blocks, H, screwed down upon them. The weight, E, is in a compartment at the
lower part of the casing, in which compartment. it can move to either side to a
limited extent. Just above the weight, E, there is fixed on a small bridge or
bracket, J, fixed to the front and back of the casing, a pointed pin, K, serving as a
centre to a long index finger or pointer, L, extending upwards with its upper end in
front of a graduated scale, M. The pointer, L, is fixed in a piece, N, and has a conical
recess formed in its bottom so as with the piece, N, to be centered, on the fixed
pin, K, and the piece, N, is formed with sides extending down at the sides of the
bridge, J, and with a bottom part extending across under the bridge, J, and formed
with a middle downwardly projecting part, P. The pointer, L, and the attached
parts, N, P, are made so that their centre of gravity is as nearly as possible
coincident with the point of the pin, K, on which they are centered. The projecting
bottom part, P, extends down into a socket, Q, in the weight, E, this socket, being
for the sake of accuracy covered by a small plate, having formed in it an opening
to receive the projection, P, a slightly projecting rib on the projection, P, fitting
the opening easily.
When the instrument is used, as; for example, in testing whether what should be
vertical and horizontal surfaces are accurately so and at right angles to each other,
the weight, E, will move to one side or the other if the parts being tested are not
accurate, and by acting on the part, P, of the piece, N, to which the pointer, L, is
attached will cause the pointer to move over the graduated scale, M, to a pro-
portional extent, but multiplied or enlarged in the ratio that the top of the pointer
is more distant from the centre than the part, P, that is acted on by the weight.
When the instrument is to be capable of being used chiefly as a level I provide
it with an extended. base piece, R, which can be attached to the bottom of the
casing, Aby two pins, S.
The casing is closed by wooden or other panels; and an opening or window, T,
preferably glazed, is provided to render the scale, M, and upper end of the
pointer, L, visible.. The weight, E, may be suspended by two or four cords or by
fine, wires.
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. Constructing plumb levels and the like in the improved manner, substantially,
as herein before described and as shown in the accompanying drawings.
2. In plumb levels and analogous instruments, combining with a suspended
weight a long index or pointer centered near its lower end and arranged to have its

page_text: lower end or a part fixed thereto acted on by the weight, substantially as herein-
before described.
Dated this Seventeenth day of November 1893.
EDMUND HUNT,
Applicant's Agent.