improvements in the Manufacture of
Year: 1898

page_text: Date of Application, 19th Oct., 1898
Complete Specification Left, 16th June, 1899-Accepted, 22nd July, 1899
Wp Levels.
I, HARRY JOSEPH RABONE, of Hockley Abbey Works, Whitmore Street, Birming-
ham, in the County of Warwick, Manufacturer, do hereby declare the nature of this
invention to be as follows:-
My invention consists of the improvements hereinafter described in the manufacture
of spirit levels which improvements are especially applicable to spirit levels of the
kind used by masons and others but are also applicable to other kinds of spirit
levels.
I will describe my invention as applied to a mason's spirit level.
In spirit levels of the kind referred to as ordinarily constructed the spirit tube is
secured in a cast metallic box or frame by plaster of Paris or other cement with which
the said box or frame is filled. My invention has for its object to improve the
manufacture of the metallic box or frame in which the spirit tube is set and this I
effect as follows.
I make by a stamping or piercing operation from thin sheet brass or other ductile
sheet metal or alloy a slotted plate or blank the slots in the said plate or blank
constituting the openings in the upper side of the box or frame by which the spirit
tube is exposed to view. By a raising or pressing operation I give to the said plate
or blank a trough like figure in cross section the sides of the said trough being
parallel. The collapsing of the parallel sides of the trough like sheet metal box or
frame is prevented by cross stays extending from one of the edges of the box or
frame to the other edge. The said cross stays are either formed in one piece with the
box or frame or separate therefrom and secured thereto by riveting or soldering.
The spirit tube is mounted in the box or frame described in the ordinary way and
the said box or frame is attached to the wooden body of the spirit level by screws
also in the ordinary way.
Dated this Nineteenth day of October 1900
W. T. WHITEMAN,
Agent for the Applicant.
improvements in the Manufacture of Spirit Levels.
I, HARRY JOSEPH RABONE, of Hockley Abbey Works, Whitmore Street, Birming-
ham, in the County of Warwick, Manufacturer, do hereby declare the nature of my
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
My invention consists of the improvements hereinafter described in the manufac-

page_text: ture of spirit levels which improvements are especially applicable to spirit levels of
the kind used by masons and others but are also applicable to other kinds of spirit
levels.
I will describe my invention as applied to a mason's spirit level.
In spirit levels of the kind referred to as ordinarily constructed the spirit tube is
secured in a cast metallic box or frame by plaster of Paris or other cement with which
the said box or frame is filled. My invention has for its object to improve the manu-
facture of the metallic box or frame in which the spirit tube is set and this I effect
as follows:
--
I make by a stamping or piercing operation from thin sheet brass or other ductile
sheet metal or alloy, a slotted plate or blank the slots in the said plate or blank con-
stituting the openings in the upper side of the box or frame by which the spirit tube
is exposed to view. By a raising or pressing operation I give to the said plate or
blank a trough like figure in cross section the sides of the said trough being parallel.
The collapsing of the parallel sides of the trough like sheet metal box or frame
is prevented by cross stays extending from one of the edges of the box or frame to
the other edge. The said cross stays are either formed in one piece with the box or
frame or separate therefrom and secured thereto by riveting or soldering.
Figure 1 of the accompanying drawing represents in plan the sheet metal blank
from which the metallic box or frame of a spirit level is made according to my
invention.
Figure 2 represents in elevation, Figure 3 in plan and Figure 4 in end elevation
the trough like box made by a pressing operation from a blank of the kind represented
in Figure 1.
Figure 5 represents in plan the said trough shaped box after the piercing of the
upper face or front.
Figure 6 represents one of the short stays by which the parallel sides of the trough
are prevented from collapsing.
Figure 7 represents in plan of underside the sheet metal box or frame after the
application thereto of two of the short stays Figure 6.
Figure 8 represents in plan a portion of a finished spirit level having a sheet metal
box or frame according to my invention.
Figures 9 to 15 both inclusive represent modifications of my invention hereinafter
particularly described.
The saine letters of reference indicate the same parts in the several figures of the
drawing.
a is the trough like box made by a pressing operation from the sheet metal blank
Figure 1, and b, b (Figure 5) are the slots in the front or face of the same made by a
subsequent piercing operation or made in the blank Figure 1; c, c are the cross stays
(one of which is shown separately in Figure 6) by which the sides of the trough like
box or frame are prevented from collapsing the said stays being fixed, preferably by
soldering or brazing, to the edges of the open side of the trough as indicated in dotted
lines in the elevation Figure 4.
The spirit tube d (Figure 8) is mounted in the box or frame a in the ordinary way
and the said box or frame a is attached to the wooden body e of the spirit level by
screws f, f, also in the ordinary way.
'
Instead of narrow crossing stays c, c of the kind represented in Figures 6 and 7, a
long strip or continuous crossing stay g of sheet metal (see the plan of underside
Figure 9 and section Figure 11) may be employed. In this case the inner sides of the
trough have grooves (see Figure 10) made in them in which the edges of the strip
or continuous stay g take on the sliding of the strip in place the said strip completely
or nearly closing the open side of the trough.
h
Or the parallel sides of the trough like box may be prevented from collapsing in the
manner represented in elevation in Figure 12 and section in Figure 13.
In this case a V shaped tooth 2 is made on each side of the trough like box a
which teeth take in corresponding notches or recesses in the wooden body e as seen
in Figure 13.

page_text: Where thought necessary or desirable two or more teeth a² may be provided at
each side of the box or frame (.
According to another modification, represented in Figures 14 and 15, metallic or
other projections i, i are secured to the wooden body e of the spirit level on either
side of which projections i the edges of the trough like box a of the spirit level take
as seen in Figure 15 and are thereby supported against forces tending to a collapse of
the sides.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed I declare that I claim
as my invention of "Improvements in the manufacture of spirit levels."
Making the metallic boxes or frames for the reception of the spirit tubes of spirit
levels from sheet metal, the parallel sides of the trough like sheet metal boxes or
frames being supported, so as to prevent the collapse of the said parallel sides, by
short crossing stays or by a continuous crossing stay or by other equivalent means
substantially as herein before described and illustrated in the accompanying
drawing.
Dated this Fourteenth day of June 1899.
HARRY JOSEPH RABONE.