IMPROVEMENTS IN SPIRIT LEVELS AND PLUMB SPIRIT LEVELS
Year: 1872

page_text: LETTERS PATENT to John Rabone, of Birmingham, in the County
of Warwick, Manufacturer, for the Invention of “IMPROVEMENTS IN
SPIRIT LEVELS AND PLUMB SPIRIT LEVELS." -A communication from
abroad by William Kenyon, of New Britain, Connecticut, United
States of America.
Sealed the 6th December 1872, and dated the 2nd July 1872.
PROVISIONAL SPECIFICATION left by the said John Rabone at the
Office of the Commissioners of Patents, with his Petition, on the
2nd July 1872.
I, JOHN RABONE, of Birmingham, in the County of Warwick,
Manufacturer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN SPIRIT LEVELS AND PLUMB SPIRIT LEVELS," to be as
follows:-
The said Invention consists of the arrangements or combinations of
parts herein-after described for the purpose of effecting the adjustment
of spirit levels and plumb spirit levels, the said Invention being
especially applicable to such spirit levels and plumb spirit levels as are
mounted in bars or stocks of wood, but is also applicable to the adjust-
ment of spirit levels and plumb spirit levels otherwise mounted.
In constructing a spirit level according to the said Invention, the
spirit glass or bubble tube is fixed in a light metallic or other box or

page_text: case, the said box or case being open at its top and sides for the purpose
of exhibiting the upper portion of the said spirit glass or bubble tube.
The said bubble tube is fixed in the said box or case by plaster of Paris
or other cement. The said metallic box or case is connected at one end
to the under side of the top plate of the level by means of a hinge joint,
the outer knuckles of the said joint being fixed to the under side of the
said top plate, and the middle knuckle being made on one end of the said
metallic box or case. The other end of the metallic box or case is
provided with a screw box into which a screw passing through the top
plate takes. Between the under side of the top plate and thę said screw
box is a strong spiral or other spring by which the end of the metallic
box or case carrying the screw box is pressed from the top plate. By
driving home more or less the said screw, the head of which lies flush
with the upper face of the top plate, one end of the metallic box or case
is raised or lowered, the other end turning on its hinge joint. The
position of the spirit glass or bubble tube may be thus adjusted with the
greatest nicety.
In applying the said Invention to plumb spirit levels the-joint-spring-
_and_screw-described are applied to the plate carrying the metallic box or
case in which the bubble tube is cemented, the said metallic box or case
being fixed to the middle of the said plate and at right angles thereto.
The adjustment is effected by driving home the screw more or less, as
described with respect to a spirit level.
The hinge joint described may be dispensed with and the metallic box
or case carrying the bubble tube may be secured and adjusted at each
end by means of a screw, screw box, and spring of the kind described. Or
the hinge joint instead of being at one end of the metallic box or case
may be situated at the middle thereof and the adjustment effected by
means of a screw, screw box, and spring at one or both ends.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Second day of July, in the year of
our Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Rabone, Her special license that
I, the said John Rabone, my executors, administrators, and assigns, or
such others as I, the said John Rabone, my executors, administrators,
and assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term therein expressed,
should and lawfully might. make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN SPIRIT LEVELS AND
PLUMB SPIRIT LEVELS," a communication to me from abroad by William
Kenyon, of New Britain, Connecticut, United States of America,
upon the condition (amongst others) that I, the said John Rabone,
my executors or administrators, by an instrument in writing under
my, or their, or one of their hands. and seals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Rabone, do hereby declare
the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement thereof, that is to say:—
The said Invention consists of the arrangements or combinations of
parts herein-after described for the purpose of effecting the adjustment
of spirit levels and plumb spirit levels, the said Invention being
especially applicable to such spirit levels and plumb spirit levels as are
mounted in bars or stocks of wood, but is also applicable to the adjust-
ment of spirit levels and plumb spirit levels otherwise mounted.
In constructing a spirit level according to the said Invention the
spirit glass or bubble tube is fixed in a light metallic or other box or
case, the said box or case being open at its top and sides for the purpose
of exhibiting the upper portion of the said spirit glass or bubble tube.
The said bubble tube is fixed in the said box or case by plaster of Paris
or other cement. The said metallic box or case is connected at one end

page_text: to the under side of the top plate of the level by means of a hinge joint,
the outer knuckles of the said joint being fixed to the under side of the
said top plate, and the middle knuckle being made on one end of the
said metallic box or case. The other end of the metallic box or case is
provided with a screw box, into which a screw passing through the top
plate takes. Between the under side of the top plate and the said screw
box is a strong spiral or other spring by which the end of the metallic
box or case carrying the screw box is pressed from the top plate. By
driving home more or less the said screw, the head of which lies flush
with the upper face of the top plate, one end of the metallic box or case
is raised or lowered, the other end turning on its hinge joint. The
position of the glass or bubble tube may be thus adjusted with the
greatest nicety..
In applying the said Invention to plumb spirit levels, the joint spring
and screw described are applied to the plate carrying the metallic box or
case in which the bubble tube is cemented, the said metallic box or case
being fixed to the middle of the said plate and at right angles thereto.
The adjustment is effected by driving home the screw more or less as
described with respect to a spirit level.-The-hinge-joint described may
be dispensed with, and the metallic box or case carrying the bubble tube
may be secured and adjusted at each end by means of a screw, screw box,
and spring of the kind described. Or the hinge joint, instead of being at
one end of the metallic box or case, may be situated at the middle
thereof, and the adjustment effected by means of a screw, screw box, and
spring at one or both ends.
Having explained the nature of the said Invention, I will proceed to
describe with reference to the accompanying Drawings the manner in
which the same is to be performed.
Figure 1 represents partly in section and partly in elevation, and
Figure 2 in plan, a spirit level and plumb spirit level combined in a
stock or bar of wood, the said levels being constructed according to this
Invention; Figure 3 represents in side elevation (partly in section) and
plan the spirit level detached from the stock, drawn of the full size; and
Figure 4 represents a modification of the joint of the same; Figure 5
représents in elevation and plan the plumb spirit level detached from the
stock, drawn of the full size; and Figure 6 represents a modification of
the joint of the same. The same letters of reference indicate the same
parts in the several Figures of the Drawings.

page_text: is the spirit glass or bubble tube fixed in the light metallic box or
case 6 by cement in the usual manner; c is the top plate of the level
through which the upper part of the spirit glass or bubble tube a.is
exhibited (see Figure 2). To the top plate o.of the level the box or
case 6 is connected by a joint d at one end and by a screw e and screw
box fat the other end. The joint is formed of two outer knuckles d³,
d³,
on the end of the box or case b, between which a middle knuckle & on
the top plate c fits; the said knuckles being jointed together by a cross
pin d. Or the knuckles of the box 6 and top plate c may be made in
the manner represented in Figure 4, that is to say, the middle knuckle.
may be made on the box or case 6 and the outer knuckles on the top
plate c. The screw box f at one end of the tube 6 is best seen in
Figure 3, and the screw e which takes into the said screw box passes
through the top plate c. Between the under side of the top plate cand
the screw box fa strong spiral (or other) spring 9 is situated. By means
of the said spring 9 the screw box end of the metallic box or case 6 of
the level is pressed from the top plate c, and the head of the screw e
maintained flush with the upper face of the said top plate.
39
g
The manner in which the spring seats itself above the screw box fis
. best seen in Figure 3. In order to accurately adjust the position of the
spirit glass or bubble tube a carried in the case or box 6, the screw e is
turned in one or other direction. When the said screw is turned in one
direction the screw box-end f of the box or case 6 is raised on the said
screw, and when the said screw is turned in the opposite direction the
screw box end fis lowered on the screw. The screw box and ƒ of the
box or case 6 is thereby raised or lowered, its opposite end turning on the
joint pin d. The position of the bubble tube a may in this way be
adjusted with the greatest nicety, the level being firmly fixed in its
adjusted position by the action of the spring g.
} I will now describe the plumb spirit level represented in Figures 1, 2,
5, and 6; h is the bubble tube of the plumb level, cemented in the
metallic box or case i. To the top of the said box or case i the top
plate is affixed. On the under side of one end of the plate k is an
eye 7, through which a pin m passes for jointing the plumb level to the
5 stock or bar. Or two eyes 1, 1, may be made on the under side of the
top plate, for the same purpose as illustrated in Figure 6. Through
the other end of the top plate a screw n passes, the said screw taking.
into the stock, as represented in Figure 1. Around the stem of the
°

page_text: screw n is a coiled spring p which bears against the under side of the
top plate k and tends to raise that end of the said plate at which it is
situated. By turning the screw n in one or other direction the
unjointed end of the plate. is raised or lowered, the other end turning
on its joint m. The position of the bubble tube h of the case or box i 5
may thus be accurately adjusted. As the unjointed end of the top
plate k is raised or lowered by the turning of the screw n, the said plate
is maintained in contact with the head of the screw so as to fix the
adjusted position of the level by means of the spring p. The hinge
joint l, m, of the plumb spirit level may be dispensed with, and the 1
fixing and adjusting parts n, p, be placed at each end of the top
plate k.
Figures 7 and 8 represent modifications of the spirit level, represented
in Figures 1, 2, 3, and 4.
Figure 7 represents in side elevation and plan of upper side a spirit 1
level in which the hinge joint of the box or case is dispensed with, and
the metallic box or case 6 adjusted by a screw box f, screw e, and
spring g at each end of the said box or case, the said parts serving also
_to_connect-the-box-or-case-to-the-top-plate-c. In this arrangement the
adjustment of the level is effected by turning in one or other direction 2
one or other or both of the screws e, e.
Figure 8 represents in side elevation, partly in section, a spirit level
in which the joint d of the metallic box or case 6 is situated at the
middle of the box or case b, and the adjustment effected by means of a
screw e, screw box f, and spring 9, at both ends of the box or case b. Or 2
the screw, screw box, and spring may be situated at one end only of the
box or case b. The adjustment is effected in the last arrangements by
driving home more or less the single screw or one or both of the screws
when two are employed.
Although I have only represented in the accompanying Drawings 3
such spirit levels and plumb spirit levels as are mounted in bars or
stocks of wood, yet the said Invention may be applied to spirit levels and
plumb spirit levels otherwise mounted.
Having now described the nature of the said Invention and the
manner in which the same is to be performed, I wish it to be understood 3
that I do not limit myself to the precise details herein-described and
illustrated, as the same may be varied without departing from the

page_text: nature of the said Invention. But I claim as the said Invention the
improvements in spirit levels and plumb spirit levels herein-before
described and illustrated in the accompanying Drawings, that is to say,
connecting one end of the metallic or other box or case in which the
spirit glass or bubble tube of the spirit level is cemented to the under
side of the top plate of the level by means of a hinge joint, and the other
end of the said box or case to the said top plate by means of a screw,
screw box, and coiled or other spring, substantially as described and
illustrated, whereby the adjustment of the position of the spirit glass or
bubble tube may be effected with the greatest nicety.
Also the modification described and illustrated, in which the hinge
joint is dispensed with, and the adjusting and fixing parts are situated at
both ends of the box or case.
Also the modification described and illustrated, in which the hinge
joint is placed at the middle of the box or case, and the adjusting parts
are situated at one end or at both ends of the box or case.
Also constructing the adjusting and fixing mechanism of plumb spirit
levels, substantially in the manner described and illustrated.
In witness whereof, I, the said John Rabone, have hereunto set
my hand and seal, this Twenty-third day of December, in the
year of our Lord One thousand eight hundred and seventy-two.
Witness,
RICHARD SKERRETT,
Clerk to George Shaw,
Birmingham.
JOHN RABONE. (L.S.)