IMPROVEMENTS IN SECTIONAL CAST BARS APPLICABLE TO THE FURNACES OF LOCOMOTIVE STEAM ENGINES
Year: 1877

page_text: LETTERS PATENT to Thomas Samuel Dobson, of the Town and County of the
Town of Nottingham, for the Invention of "IMPROVEMENTS IN SECTIONAL
CAST BARS APPLICABLE TO THE FURNACES OF LOCOMOTIVE STEAM ENGINES."
Sealed the 26th June 1877, and dated the 27th April 1877.
"
PROVISIONAL SPECIFICATION left by the said Thomas Samuel Dobson at
the Office of the Commissioners of Patents on the 27th April 1877.
THOMAS SAMUEL DOBSON, of the Town and County of the Town of Nottingham.
IMPROVEMENTS IN SECTIONAL CAST BARS APPLICABLE TO THE FURNACES OF
LOCOMOTIVE STEAM ENGINES,"
In each furnace I employ a number of main bars either of the same length or
of divers lengths according to the shape of the fire-box; the ends of these bars are
made the reverse shape to the bearing surfaces upon which they lie; these main
bars are cast of deeper section at the centre of their length than at their ends; they
are also made thinner on their lower and upper surfaces; upon their wedge-shaped
upper surfaces I place one or more lengths of a sectional bar, each length being
slotted on its lower side, or having two or more projections which clip the wedged
upper surface of the main bar; the upper surface of each sectional length forms two
or more alternately reversed semicircles, each of which is slotted, each slot being
beveled from the top side downward and outwards, and the outside of each semi-
circle is beveled downward and inwards; besides which each sectional length has
a stud at one end and a hole at the opposite end to receive the stud on the end of
the next adjoining sectional length, each of which also has one or more studs on
the under side which take into right angled slots on the top wedged surface of the
main bars; such arrangement enables me to lock the sectional lengths firmly to
each other and to the main bars, and readily allows a burnt or broken sectional
length to be taken out and a new one to be put in its place.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Samuel Dobson in the Great Seal Patent Office on the 19th
October 1877.
THOMAS SAMUEL DOBSON, of the Town and County of the Town of Nottingham,
"IMPROVEMENTS IN SECTIONAL CAST BARS APPLICABLE TO THE FURNACES OF
LOCOMOTIVE STEAM ENGINES."
In each furnace I employ a number of main bars either of the same length or of
divers lengths, according to the shape of the fire-box; the ends of these bars are
made the reverse shape to the bearing surfaces upon which they lie; these main
bars are cast of deeper section at the centre of their length than at their ends; they
are also made thinner on their lower and upper surfaces; upon their wedge-shaped
upper surfaces I place one or more lengths of a sectional bar, each length being
slotted on its lower side or having two or more projections which clip the wedged
upper surface of the main bar; the upper surface of each sectional length forms
two or more alternately reversed semicircles, each of which is slotted, each slot
being bevelled from the top side downward and outwards, and the outside of each
semicircle is bevelled downward and inwards; besides which each sectional length
has a stud at one end and a hole at the opposite end to receive the stud on the
end of the next adjoining sectional length, each of which also has one or more studs
on the under side which take into right angled slots on the top wedged surfaces
of the main bars; such arrangement enables me to lock the sectional lengths firmly
to each other and to the main bars, and readily allows a burnt or broken sectional
length to be taken out and a new one to be put in its place.
Figures 1, 2, and 3 represent respectively a plan, side view, and end view of one
of the main bars I employ. Like views of another main bar being shewn at
Figures 4, 5, and 6.
Figures 7, 8, and 9 represent in plan, side view, and end view two lengths of
sectional perforated bars; and Figure 10, two other lengths of sectional perforated
bars.
In each furnace I employ a number of main bars, as shewn at Figures 1 to 3,
either of the same length or of divers lengths, according to the shape of the fire-box;
the ends or shoulders A. of these bars are made the reverse shape to the bearing
surfaces upon which they lie; these bars are cast of deeper section at the centre of
their length than at their ends, they are also made thinner on their lower and
upper surfaces; upon their wedge-shaped upper surfaces I place one or more lengths
of a sectional perforated bar, like unto those shewn in plan at Figures 7 and 10,
but I do not confine myself to any particular pattern of perforation; whatever
pattern of perforation I employ each perforation is bevelled from the top side down-
ward and outwards at about the angle shewn on the end view, Figure 9; each
sectional length has one or more studs or flanges B on the under side which lie
upon and between the top wedged surfaces of the main bars; the flanges have holes
cast in them through which holes a rod C is passed; this rod is shewn by dotted
lines at each end of Figure 7, and in side view and section respectively at Figures 8
and 9, this rod being passed through the holes in the flanges after the sectional
lengths are placed in position keep them in place. The shoulders of the main bars
are of such a length that each next adjacent series of sectional bars are kept apart
the same distance as the width of the central slots in the sectional bars.
When sectional perforated bars are used in a furnace six feet, more or less, in
length, I employ two or more lengths of main bars, like unto the one shewn at
Figures 4 to 6, the shoulders D of which rest upon the bridge at the back and the
dead plate at the front of the furnace and upon a cross bar or bars between the

page_text: bridge and dead plate; each length of such main bars carry as many sectional
lengths of perforated bars as will entirely cover their whole length, the sectional
bars lying over the shoulders of the main bars, thus forming a level grate surface
equally perforated from end to end and effectually protecting the shoulders of the
main bars from the heat of the fuel.
Either of the above-described arrangements enable me to lock the sectional
lengths firmly to each other and to the main bars, and also readily allows a burnt
or broken sectional length to be taken out and a new one to be put in its place.
The sectional bars and main bars are applicable to the furnaces of marine engine
steam boilers, the furnaces of locomotive engines, and stationary engines.
Having thus fully described the nature of my said Invention, and the manner of
performing the same, I wish it understood that I claim, the general arrangement
and combination of sectional bars in conjunction with main bars, substantially as
herein-before described and illustrated in the accompanying Drawings.
In witness whereof, I, the said Thomas Samuel Dobson, have hereunto set my
hand and seal, this Eighteenth day of October, in the year of our Lord
One thousand eight hundred and seventy-seven.
Witness,
H. W. GOUGH, C.E.,
Nottingham.
THOMAS SAMUEL DOBSON. (L.S.)