An Improved Spirit Level, Plumb, and Clinometer.
Year: 1891

page_text: Date of Application, 15th May, 1891
Complete Specification Left, 15th Feb., 1892-Accepted, 14th May, 1892
PROVISIONAL SPECIFICATION.
An Improved Spirit Level, Plumb, and Clinometer.
I WILLIAM WILSON HORN of the firm of Horn and Son of 151 Strand in the
County of Middlesex Patent Agent do hereby declare the nature of this invention
(a communication to me from Henry Green of Hartford State of Connecticut
and John J. Tower of New York United States of America Inventors) to be as
follows:-
This my invention relates to an improved spirit level plumb and clinometer and
more particularly to the class of pocket spirit levels which are adapted to be
attached to a straight edge a boring tool or similar articles or to be used to level
plumb or determine the angle of inclination of small objects.
The object of this invention is to provide a simple and cheap instrument of this
class wherein the spirit frame can be easily moved and adjusted in position to read
from the scale the desired information without the loosening and fastening of
clamp screws and without any wear upon the parts which will impair the efficiency
of the tool.
The back plate which is preferably of brass has a straight edge along its base.
Projecting from the rear of this plate upon each side are a pair of ears provided
with a straight edge and lug against which the back and side of a rule may be
clamped and held by means of a clamp screw in order to provide an extended base
when it is used to level long objects. These cars are also provided with central
V-shaped notches into which the shank of a boring tool may be clamped by the set
screw when it is desired to utilize the device for determining the proper direction
of a hole that is to be bored. A central boss is formed on the front of the plate
and upon the periphery of this is loosely fitted the annular rim of a frame which
bears any ordinary spirit glass. A portion of the annular rim is split and the ends
are held together by means of a screw so that the rim may be made to bind with
any degree of friction upon the periphery of the boss on the back plate. The face
of the boss is preferably graduated into degrees near its edge which degrees will
register with an index line upon the edge of the rim of the glass-frame so that the
difference of degree of inclination between the back plate and the spirit glass frame
can be read. The periphery of the boss presents a large bearing surface which
will not wear away so that the parts will become loose and the frame may be readily
rotated to any desired degree.
Dad thin 15th da.. of M. 1901
HORN & SON,
Applicant's Agents.
COMPLETE SPECIFICATION.
An Improved Spirit Level, Plumb, and Clinometer.
I WILLIAM WILSON HORN of the firm of Horn & Son of 151 Strand in the
County of Middlesex Patent Agent do hereby declare the nature of this invention
a communication to me from Henry Green of Hartford in the State of
Connecticut and John J. Tower of the City and State of New York both of
United States of America Inventors and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement :-
The invention relates to the class of pocket spirit-levels, or spirit-levels which

page_text: are adapted to be attached to a straight edge, a boring tool, or similar articles
or to be used to level, plumb, or determine the angle of inclination of small
objects.
The object of the invention is to provide a simple and cheap instrument of this
class wherein the spirit, frame-can be evenly and easily moved and located in
position to read from the scale the desired information without the loosening and
fastening of clamp-screws and without any wear upon the parts which will impair
the efficiency of the level.
Referring to the accompanying drawings,
Figure 1 is a side view of the instrument, showing in full lines its position when
in use as a level, and the position of the parts in dotted line when it is used as a
plumb.
Fig. 2 is a top view.
Fig. 3 is a vertical central section and
Fig. 4 is a modification hereinafter described.
In the accompanying views, the letter a indicates the back plate, which is
preferably formed of brass, with a straight-edge a¹ along its base.
Projecting from the rear of this plate upon each side are a pair of cars b, that
are provided with a straight-edge and lug against which the back and side of a
rule may be clamped and held by means of a clamp-screw c. that fits a threaded
socket through the end of the lug or bracket d, that also projects rearward from
the back of the plate, in order to provide an extended base for the tool wher it is
used to level long objects. These ears are also provided with central V-shaped
notches e, into which the shank of a boring-tool may be clamped by the set-screw
when it is desired to utilize the device for determining the proper direction of a
hole that is to be bored. A central boss f is formed on the front of the plate, and
upon the periphery of this is loosely fitted the annular rim of the frame g, which
bears any ordinary spirit-glass. A portion of the annular rim g' is split, and the
ends of the split portion are held together by means of a screw, which passes
through threaded sockets in lugs on the ends, so that the rim may be made to bind
with any degree of friction upon the periphery of the boss on the back plate. The
periphery of the boss. may be undercut to hold the rim in place, or a plate may be
secured by means of a screw to the face of the boss, with its edges slightly over-
lapping the inner edge of the rim to hold it in place upon the boss, as indicated in
dotted outline in Fig. 3 and in Fig. 4, and the face of the boss or this plate, if used,
is preferably graduated into degrees near its edge, which degrees will register with
an index line upon the edge of the rim of the glass-frame, so that the difference of
degree of inclination between the back plate and the spirit glass frame may be read.
The split rim or strap may be clamped with any degree of tightness by means of
the screw upon the periphery of the box, which presents a large bearing surface
which will not wear away so that the parts will become loose, and the frame may
be readily rotated to any desired degree. As the friction between the parts is
even and firm, there is no need of a clamp-screw to bind and set the parts in
position when adjusted, and which works loose when the frame is rotated in one
direction, or which tightens when the frame is rotated in the opposite direction, and
which is liable to move the parts and change the reading of the index when it is
being tightened.
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 1
claim is :-
•
1. In a spirit-level, in combination, a back plate having a circular boss on; one
face, a frame holding a spirit glass, with a split annular rim encircling the boss and
a clamp-screw joining the split ends of the rim of the frame, substantially as
specified.
2. In a spirit-level, in combination, a back plate having a circular boss with-an
undercut edge on one face, a frame holding a spirit glass, with a split annular rim

page_text: encircling the periphery of the boss, and a clamp-screw joining the split ends of the
rim of the frame, substantially as specified.
3. In a spirit-level, in combination, a back plate having a circular boss on one
face and a rearward projecting lug or bracket bearing a clamp-screw on the opposite
face, a frame holding a spirit glass, with a split annular rim encircling the boss, and
adapted to be retained thereon, substantially as specified and illustrated.
Dated this 15th day of February 1892.
HORN & SON,
Applicant's Agents.