IMPROVE- MENTS IN GRATE BARS
Year: 1866

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in
the County of Middlesex, Gentleman, for the Invention of "IMPROVE-
MENTS IN GRATE BARS."-A communication from abroad by Samuel
Harrison. of Philadelphia, Pennsylvania, United States of America.
Sealed the 26th March 1867, and dated the 4th October 1866.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents, with his Petition, on the
4th October 1866..
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN GRATE BARS," a communication to me from abroad by
Samuel Harrison, of Philadelphia, Pennsylvania, United States of America,
to be as follows:-
This Invention relates to an improvement in that class of grate bars which
consist of a number or group of ribs cast together, with spaces between the
ribs, and the improved grate bar consists of a deep and shallow rib or ribs
combined in one casting, substantially as described hereafter, so that the bar
may be more easily moulded and cast, may afford a better circulation of air

page_text: between the ribs, may be less liable to be choked with cinders and slag, and
be lighter, and consequently more economical, than ordinary grate bars having
a number of ribs of uniform depth.
The improved bar is composed, according to one form, of three longitudinal
ribs connected together at the opposite ends, and at suitable intermediate
points, by transverse webs, the whole being cast in one piece. The outside
ribs are much shallower than the middle rib, and are made in the form of an
arch on the under side; they may, however, be straight or of a convex form.
The middle rib is made in the form of an inverted arch. These ribs are
arranged at a proper distance apart to suit the fuel which has to be used in
the furnace of which a number of these bars form the grate, and on the
exterior of the outer ribs are the usual projections, by means of which the bars
are maintained at a proper distance apart from each other.
The advantages of the improved grate bar may be enumerated and described
as follows:
First, they can be moulded and cast with greater facility than ordinary bars
in which a number of ribs of uniform depth are cast together.
Second, there will be a more free circulation of air through the spaces
between the ribs of the improved bar than through bars having ribs of uniform
depth, as the air has to pass through much shallower openings in the former
than in the latter case.
Third, there is less liability of the spaces between the ribs becoming choked
with slag and cinders.
Fourth, the intermediate or centre rib of the form described imparts the
desired vertical rigidity to the bar; hence the outer ribs may be of the reduced
depth described, thereby effecting a corresponding reduction in the weight of
the bar, and a saving of material.
Although I prefer in ordinary cases a bar composed of three ribs, as
described above, bars with five ribs, or with six ribs, or even with two ribs,
may be made and used with good results. The outer ribs at each end of the
bar project below the middle rib, the outer ribs only resting on the bearer.
This arrangement possesses two advantages: first, a more steady bearing is
afforded to the bars than if the whole of the ribs rested on the bearers;
second, openings are presented for the free passage of air. The upper edges
of the rib may be rounded, or a groove may be formed in the upper edge of
each rib.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Henry Johnson in the Great Seal Patent Office on
the 4th April 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourth day of October, in the year of our Lord
One thousand eight hundred and sixty-six, in the thirtieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said John Henry Johnson, Her special license that I, the said John
Henry Johnson, my executors, administrators, and assigns, or such others as
I, the said John Henry Johnson, my executors, administrators, or 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 "IM-
PROVEMENTS IN GRATE BARS," a communication to me from abroad by Samuel
Harrison, of Philadelphia, Pennsylvania, United States of America, upon the
condition (amongst others) that I, the said John Henry Johnson, my executors
or administrators, by an instrument in writing under my hand and seal, should
particularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be perfornied, 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 Henry Johnson, 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, reference being had to the accompanying Drawings, and
to the letters and figures marked thereon, that is to say :-
The said Invention relates to an improvement in that class of grate bars
which consist of a number or group of ribs cast together with spaces between
the ribs, and the improved grate bar consists of a deep and shallow rib or ribs
combined in one casting, substantially as described hereafter, so that the bar
may be more easily moulded and cast, may afford a better circulation of air
between the ribs, may be less liable to be choked with cinders and slag, and
be lighter, and consequently more economical, than ordinary grate bars having
a number of ribs of uniform depth.

page_text: And in order that the said Invention may be fully understood, I shall now
proceed more particularly to describe the same, and for that purpose I shall
refer to the several Figures on the Sheet of Drawings hereunto annexed, the
same letters of reference indicating corresponding parts in all the Figures.
Figure 1 is a side view of the improved grate bar; Figure 2 is a plan view;
Figure 3, a transverse section on the line 1, 2, Figure 1; Figure 4, an end
view; Figure 5, a Diagram illustrating one of the advantages of the Invention;
Figure 6, an end view of two bars resting on a bearing. The remaining
Figures illustrate modifications of the improved grate bar.
On reference to Figures 1, 2, 3, 4, and 6, A is the bar, which in the
present instance is composed of the three ribs a, a³, and a", connected together
at the opposite by webs b, b, and at suitable intermediate points by webs d, d',
and e, the whole being cast in one piece.
The outside ribs a and all are much shallower than the middle rib, and, as
seen in Figure 1, are made in the form of an arch on the under side; they
may however be straight, as shown in Figure 18, or of the form shown in
Figure 12. The middle rib is made in the form of an inverted arch.
The ribs a, a, and all are arranged at a proper distance apart, to suit the
fuel which bas to be used in the furnace, of which a number of these bars form
the grate, and on the exterior of the outer ribs a and all are the usual pro-
jections f, by means of which the bars are maintained at a proper distance
apart from each other.
The advantages of the improved grate bar may be enumerated and described
as follows:-
First, they can be moulded and cast with greater facility than ordinary
bars in which a number of ribs of uniform depth are cast together. This will
be readily understood by reference to the Diagram, Figure 5, which illustrates
the impression in the sand made by a pattern of the improved bar; the walls
y, y, of sand between the cavities formed by the ribs on the pattern being
much more substantial than if the ribs were of uniform depth, there is conse-
quently less danger of bad castings, as well as less manipulation required in
dressing and finishing the mould.
Second, there will be a more free circulation of air through the spaces
between the ribs of the improved bar than through bars having ribs of uniform
depth, as the air has to pass through much shallower openings in the former
than in the latter case (see arrows, Figure 3).
Third, there is less liability of the spaces between the ribs becoming choked
with slag and cinders, as will be readily understood without explanation.
Fourth, the intermediate rib a¹ of the form shown in parts the desired

page_text: vertical rigidity to the bar; hence the outer ribs may be of the reduced depth
illustrated and described, thereby effecting a corresponding reduction in the
weight of the bar and a saving of material.
Although I prefer in ordinary cases a bar composed of three ribs, as
described above, bars with five ribs, as seen in Figure 9, or with six ribs, as
shewn in Figure 8, or even with two ribs, as illustrated in Figure 7, may be
made and used with good results.
It will be seen on reference to Figures 1 and 6 that the outer ribs at each
end of the bar project below the middle rib, the outer ribs only resting on the
bearer X.
This arrangement possesses two advantages, first, a more steady bearing
is afforded to the bars than if the whole of the ribs rested on the bearers;
second, openings t, t, Figure 6, are presented for the free passage of air in the
direction pointed out by the arrows, Figure 1.
The upper edges of the rib may be rounded, as seen in Figure 14, or a
groove may be formed in the upper edge of each rib, as shown in Figure 11.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe in conclusion that what I consider to be novel and
original, and therefore claim as the Invention secured to me by the herein-
before in part recited Letters Patent is, a grate bar consisting of a deep
and shallow rib or ribs combined in one casting, substantially as and for the
purpose herein-before described.
In witness whereof, I, the said John Henry Johnson, have to this my
Specification hereunto set my hand and seal, this Twenty-sixth day of
March, One thousand eight hundred and sixty-seven.