IMPROVEMENTS IN AUTOMATIC STOKING FURNACES, AND IN STEAM BOILERS, MECHANISM AND FITTINGS CONNECTED THEREWITH.
Year: 1878

page_text: LETTERS PATENT to John Auld, of the Firm of David Auld and Sons, of
Glasgow, in the County of Lanark, North Britain, Engineers, for the Invention
of "IMPROVEMENTS IN AUTOMATIC STOKING FURNACES, AND IN STEAM BOILERS,
MECHANISM AND FITTINGS CONNECTED THEREWITH.
Sealed the 21st January 1879, and dated the 31st October 1878.
PROVISIONAL SPECIFICATION left by the said John Auld at the Office of
the Commissioners of Patents on the 31st October 1878.
JOHN AULD, of the Firm of David Auld and Sons, of Glasgow, in the County of
Lanark, North Britain, Engineers. "IMPROVEMENTS IN AUTOMATIC. STOKING
FURNACES, AND IN STEAM BOILERS, MECHANISM, AND FITTINGS CONNECTED THERE-
WITH."
This Invention has reference to new or improved arrangements or combination
of the parts of automatic stoking furnaces, and of the boilers, actuating mechanism,
and fittings connected therewith, which will be more efficient and durable than
such furnaces have been as heretofore constructed. And the nature and novelty of
the Invention consist under one modification or combination of the parts in
arranging the furnace bars so as to rise and fall in alternate sets intermittently,
that is, all the odd numbers of the bars rising while the even numbers are left
down, and the even numbers rising while the odd numbers are left down, pre-
ferably over two slowly rocking or revolving transverse shafts, one under the inner
or back end of the furnace bars, and the other under the outer or front end, pre-
ferably made to project out in front of the furnace space and end of the boiler or
its building below the feeding hopper which is erected over it and made much of
an ordinary construction, with strong end frames and a sliding inner front door
and front plate, the dross or other fuel being fed into and over this front end of the
furnace bars as will be herein-after described.
Each set of furnace bars as raised have a forward reciprocating motion imparted
to them, while the lower set are being drawn back ready for being similarly

page_text: moved forward when raised as the other set are being drawn back to be similarly
raised and moved forward, all respectively and alternately so as to feed in the fuel
supplied on them from the hopper to their inner back end by the said upward and
forward motion of the alternate sets of bars, this horizontal reciprocating to-and-
fro motion being given by an oscillating, or it might be a revolving shaft, as will be
herein-after described. When the furnace bars are thus raised or lowered and
reciprocated horizontally by oscillating shafts they are fitted to rest on cam arms
or acting levers projecting upwards and backwards under the one set of bars from
their carrying and lifting and lowering shafts at each end, and upwards and
forwards for the other alternate sot of bars, the two shafts being coupled together
by a lever projecting down from each and attached by a long horizontal connecting
rod, which is oscillated by a motion taken from a cam, eccentric, or crank on a
slowly revolving first motion shaft in front, all so as to raise and lower the two
Bets of bars parallelly and alternately as stated. Each set of bars are coupled
together by arms at the front end with transverse slots in them, the one set pro-
.jecting upwards and the other downwards so as to be connected by a transverse
rod or bar passed through the slots above the one set and below the other, and thus
be reciprocated in sets by two long bars at each side of each set, or it might be
short connecting rods projecting forwards, so as to be oscillated by two sets of
corresponding duplex or double-armed levers on a transverse rocking shaft actuated
by an oscillating lever and connecting rod from a crank or eccentric on the said
first motion revolving shaft, the lower set of levers from the working shaft recipro-
cating the one set of bars by their long forward projecting ends direct by slots or
.studs, the upward or opposite projecting arms of the shaft reciprocating the other
set of bars through reciprocating guide bars or frames with arms projecting down
to corresponding slots or studs in the long forward projecting ends of the other set
of bars, all the cranks or arms and jointed rods or links of this longitudinal motion
of the bars being so set in relation to those of their raising and lowering rocking
shaft as to reciprocate each set of bars forward while they were raised, and back-
wards while lowered as before described, to carry forward the burning fuel or
small coal to the back or inner end where it would.be delivered as burned into a
back chamber for the purpose, over a plate or box covered or filled with fire-clay or
. other fireproof material close under the inner end of the fire-bars, the inner end of
which would prevent the admission of too much air at this part, and might be
made to carry the weight of the inner end of the reciprocating grate-bars when
desired, a movable door being fitted below this fireproof bridge for removing the
burnt fuel at intervals from the chamber below this, and the back flame wall after
the heat had been exhausted from it into the furnace flues along with the other
heated gases from the fuel on the grate, and when desired, an opening with
or without a closing damper may be fitted through the lower part of the flame
wall, to draw or conduct the heated spent gases from the burnt fuel in the
chamber to assist in the better utilization of these. Under the lower open end of
the fuel hopper, and some distance above the outer projecting ends of the furnace
grate-bars a reciprocating feeding in cross plate frame or bar is fitted preferably
with a sharp angled projecting ridge at the upper edge of its front face (for the
better preparation or cutting of the fuel in its forward motion) sliding on a front
feeding dumb plate or hearth below it, so that as it is reciprocated by the upper
reciprocating rods which actuate the one set of bars; it pushes a certain amount
of small coal or other fuel used over the hearth plate on to the furnace or grate-
bars below, so as to be burned and carried forward on these, all otherwise as
before stated. Or instead of this feeding frame a simple plate might be used with
a hinged or folding down front part, which as reciprocated forward would fall
and deliver the coal on to the grate over the front edge of the front dumb plate,
which might have a hinged or sliding door at its front edge capable of closing
down on the front end of the furnace bars for regulating the admission of
air to the furnace and fuel at this part, or for the insertion and working of a
poker, rake, or other fire-dressing implement below the dumb plate when desired.

page_text: The regular amount of fuel may thus be fed into the furnace under one arrange-
ment by the reciprocating stroke given to the pushing-in frame or plate, having
the inner end of their reciprocating rods screwed and fitted with adjustable
double or jam nuts, so as to allow the rods to reciprocate freely through holes or
hollow snugs in the feeding-in frame or plate to any desired extent of their throw
without moving it, and yet push it in to the remainder of its full normal throw and
position each inward stroke, or any other equally intermittent or constant differential
regulating mechanical feed motion may be employed. All these driving and
working shafts and other front fittings may be carried on cast-iron or other bracket
frames secured to the front end of the boiler or front surface plate or building,
either with or without supporting standards from the ground or floor of the
building. The first motion revolving crank shaft may be made to actuate the
gearing of one, two, or more such stoking furnaces at different speeds by differential
speed spur wheels, or cone belt pulley or both at one end, driven from any over-
head or other adjacent motive shaft, and have a single crank or eccentric for actuating
the rocking shaft of the longitudinally reciprocating mechanism, and another crank
eccentric or cam for actuating the rocking shafts for carrying and raising and
lowering the furnace bars. Stationary furnace bars, or fire-clay bricks or blocks.
may be fitted along each side of the moving fire-bars, which may be made double
or thick with long narrow cored-out vertical ash spaces or slits up their centre, and
thinned away below for lightness and strength as other furnace bars, to prevent
them from getting too hot and burning away. or. bending down in the centre, and
the upper edges or faces may be made sharp or rough with recesses to assist in
catching the fuel, and lift and carry it forward as the bars are reciprocated. When
the transverse shafts below the furnace bars are made to revolve, they would be
formed with opposite short raising and lowering projections or cam pieces, set.
alternately at opposite angles under each alternato bar, so that as the shafts revolved
they would raise the entire odd numbers of the bars as a set, while the others or
even numbers are being lowered, so as to be reciprocated horizontally when raised,
as before described; either or both revolving shafts may be driven from the first
motion shaft with pitch chain wheels on them, and an endless pitch chain passed
over these. In the case in which longitudinal reciprocating motion is given to the
two sets of furnace bars by a slowly revolving shaft in front (instead of the rocking
lever shaft described), this may be done by double cranks or eccentrics formed or
mounted on it, and made to actuate the bars direct by vertical slots in the front
end of the long or side moving bars, or by short connecting rods, which direct reci-
procating motion might also be made to give the rising and lowering motion to the
bars direct at the front end, by making the slot or moving space under the con-
necting rod, when that is used, less than that due to the vertical upward motion of
theso, so that as these come round to the top, they would always raise the bars in
front, just before carrying them forward to feed in the fuel as before described, and
the inner ends of the two sets of bars could all be similarly and alternately raised
and lowered at the extreme inner end, by connecting each set of bars together by
transverse bars at the front end, and raising them by cranks or other equivalent on
a revolving or rocking shaft under them, driven by levers or pitch chain wheels on
a front shaft driven from the first motion shaft, or the crank shaft for reciprocating
the front end of the bars before described. When a single revolving shaft is used
in front with eccentrics or cranks, these might be made to actuate a pair of two-
armed rocking levers at each side, having their lower short arm actuated by the
eccentrics or cranks, and their upper longer arms directly connected to the long
front end of the moving or connecting side bars direct of the two sets or alternate
frames of furnace bars, so as to reciprocate them longitudinally as before described
for the feeding-in of the fuel. The sliding supply door of the hopper is preferably
hung by connecting rods at each side, to connected bell cranks or other balanced
cranks with a single moving hand lever at one side, so as to be able to raise and
lower or push this sliding door up or down within the fuel hopper, to regulate the

page_text: admission or supply of fuel, a fixing quadrant being fitted to the hand lever for
securing the whole in any desired position.
When the sliding or pushing-in fuel feeder and dumb plate below the hopper is
dispensed with, the lower front sliding door of the hopper may be brought down
close to the highest level of the furnace bars; and to prevent the escape of small
coal through the front end of the bars when lowered, each bar might have a loose
end or arm jointed to it in front, carried on a roller or other equivalent below, so as
to bear up against the front edge of the hopper, and prevent the escape of the fuel,
while the bars themselves were lowered and drawn backwards, or otherwise
angular comb plates might be hinged to the lower front edge of the hopper to rise
and fall with the bars, and so prevent the escape of the small coal or fuel. In these
modifications of automatic or motive power fuel stoking furnaces for steam boilers
and other purposes herein-before described, and in all other such furnaces heretofore
in use of which I am aware, the fuel is fed in or forward from the front end of the
furnace, and therefore has to burn backwards in the direction opposite to that in
which the fuel is fed in, which has the effect with such fuel, as small dross, and
when heavy firing is necessary of causing and maintaining a smoky fire. But, by
another improvement of this Invention, the fuel is automatically fed in on to the
back of the furnace bars through one, two, or more conical or other tapered holes or
tubes through the upper part of the steam boiler or brickwork above the furnace
chamber, as the case may be, leading and conducting the dross or other fuel from
the feeding hopper and mechanism fitted above it, such as that described in the
former arrangement. By this means the "green" dross or fuel fed on to the sets of
reciprocating or other moving furnaco bars would be carried forward to the front
end of the furnace and boiler by the upward and backward motion of the bars,
instead of their upward and forward motion, as before described, so as to deliver
the burnt fuel or ashes into a close chamber for the purpose at the front end of
the boiler and furnace, instead of at the back as before described, leaving sufficient
room between this chamber and the entrance to the ordinary ash-pit below the
furnace bars for the free admission of air thereto, to support the proper combustion
of the fuel in the furnace above the bars. The fuel in this case being kindled at the
front of the furnace would burn from this backwards towards and over the "green"
coal or fuel, being fed in at the back end as before stated, and thus more effectually
evolve the gases from the "green" fuel and burn them as they are evolved, thus
preventing or burning all the smoke or gases more thoroughly than they have been
heretofore in self-stoking furnaces. When the fuel feeding tubes were formed down
through the upper part of the steam and water space of the steam boiler, they
might be lined with fire-clay bricks or tubes, to prevent the burning of the tube
plates, and risk of explosion or accident by the overheating of these.
"

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Auld in the Great Seal Patent Office on the 28th April 1879.
JOHN AULD, of the Firm of David Auld & Sons, of Glasgow, in the County of
Lanark, North Britain, Engineers. "IMPROVEMENTS IN AUTOMATIC STOKING
FURNACES, AND IN STEAM BOILERS, MECHANISM, AND FITTINGS CONNECTED THERE-
WITH."
My said Invention has reference to new or improved arrangements or combina-
tions of the parts of automatic stoking furnaces, and of the boilers and actuating
mechanism and fittings connected therewith, which will be more efficient and
durable than such furnaces have been as heretofore constructed. And in order that
the full nature, novelty, and mode of performing my said Invention may be properly
understood I shall now proceed to describe the several Figures on the two Sheets
of Drawings which I have hereunto appended for that purpose, the same reference
letters and numerals indicating the same or equivalent parts in all the Figures
where seen, and not otherwise referred to. Referring to Sheet 1 of the Drawings,
Figures 1, 2, and 3 are a front end view partly in section, and a longitudinal and a
horizontal section, all respectively of the front firing end of a duplex or two flue
horizontal cylindrical steam boiler Z with the furnaces, grates, bars A, A', fitted in
the front end of the flues Z¹, so far of an ordinary construction, but shown as fitted
with my new or improved automatic or mechanical motive power fuel stoking
furnace or moving grate bars A, A', and fittings and gearing connected therewith,
all constructed in accordance with and illustrative of one modification or general
arrangement of my said Invention or improvements. And Figures 4 to 15 are
detail views of parts and modifications detached from the general arrangement,
Figures 1 to 3, to make the construction and action of these more clear. Referring
to the modification or general arrangement shown in Figures 1, 2, and 3, on Sheet 1,
the essential features of novelty and the nature and mode of performing my said
Invention consists, under this combination of the parts, in arranging and connecting
the furnace bars A, A³, so as to rise and fall intermittently in alternate sets A, A,
and A¹, A¹, that is to say, all the odd numbers 1 to 15. of the bars A, A, are secured
together in front by slotted snugs a and a cross bar through them at all, below, so
as to be raised a short distance and time, while the even numbers 2 to 16 of the
bars A', A', (which are similarly connected by the snugs a¹ and cross bar a" above)
are lowered and left down for a short time, the even numbers rising while the odd
numbers are lowered, preferably by two rocking (or it might be revolving) and
carrying transverse shafts B, B¹, each bar A and A' resting by its under angled
edge in the V shaped carrying, guiding, and moving lateral arms 6 and 6', formed
on the opposite sides of the rocking shafts B, B₁, as in Figures 4 and 5, which
show a transverse section and under plan to an enlarged scale of one of these
shafts B and its actuating lever B", connecting rod 61, 62, and cam box b³, and
cam, on cam shaft F. The shaft B' is mounted in bearing blocks under the
inner or back end of each set of furnace bars A, A', within the furnace flues Z',
and the other shaft B in bearing brackets B², under the outer or front end of each
set of furnace bars, which are preferably inade to project out in front of the furnace
space Z¹ and end of the steam boiler Z or its building Z" so as to be under the
lower feeding mouth c of the fuel hopper C, which is erected over them, nearly
close to the front end of the boiler Z, much in an ordinary manner; and formed of.
strong front and end frames C', fitted with a counterweight sliding inner fuel
feeding or regulating door c¹, c¹, and an outer slide plate cll in front; the dross z
or other fuel is supplied to this hopper C above, being fed through the mouth c
under the door c², into, and preferably over a hearth or feed plate D, D¹, on to the
front end of the furnace bars A, A', as will be herein-after described. Each set of
furnace bars A or A', connected and raised as described, of each furnace, have a
forward reciprocating motion imparted to them, while the other lowered set as
A' or A are being drawn back ready for being similarly raised, and moved forward

page_text: when raised, as, or while the other set is being drawn back to be similarly raised
and moved forward, all respectively and alternately so as to partially raise the
fuel supplied on to the bars in front from the hopper C, and all the incandescent
fuel off the lowered bars, and feed the whole forward to the inner or back end. A*
by the said upward and forward motion of the alternate sets of bars. This hori-
zontal reciprocating to-and-fro motion of the two sets of bars of both furnaces by
the revolving cam shaft F (or it might be by an oscillating shaft) as will be herein-
after described. When the furnace bars A, A³, are thus raised or lowered vertically
by their reciprocating carrying shafts B, B¹, and reciprocated horizontally by the
revolving shaft F, as stated, each set A or A¹ is fitted to rest on their respective
cam arms or acting levers band 6' projecting upwards and backwards under the
one set of bars from the same side of their carrying and lifting and lowering
shafts B, B¹, at each end of the bars, and upwards and forwards under the 'other
alternate set of bars; the two shafts B, B¹, being coupled to act together by a
lever B projecting down from each through a long horizontal connecting rod b",
and oscillated by the short connecting rod bs and cam box 6s direct from a cam 611
or it might be by an eccentric or crank on the slowly revolving first motion cam
shaft F, carried in journal bearing brackets and standards F", secured to the front
end of the boiler Z and to the brickwork at the floor of the ash-pit Z³, the
reciprocating of which shafts B; B³, thus raise and lower the two sets of bars A
or A¹ parallelly, simultaneously, and alternately as stated; each set of bars A and A',
being coupled together by their arms a and a¹, projecting upwards and downwards
.at the front end with transverse slots in them respectively, for being connected by
a transverse rod or bar all passed through the slots, above on the one set and below
on the other set, all so as thus to be reciprocated in sets by two long bars shown
.detached in Figures 10 and 11, at the sides of each set (or it might be by short
connecting rods) projecting forward with eyes A² on them, so as to be oscillated by
two sets of corresponding duplex eccentrics f,f¹, keyed on the said slow revolving
cam motion shaft F, the eccentrics f reciprocating the one set of bars A, and
those f¹ reciprocating the other set A¹ by their long forward projecting ends and
eyes A³, as seen particularly in Figures 1 to 3 and 6 detached. The eccentrics f, f,
being so set on the shaft F, in relation to the cams 6¹¹¹, which, being segmental,
make a pause at their extreme stroke each way, and to the levers b, 61, B¹¹, of
their raising and lowering rocking shaft B, B¹, as to reciprocate.each set
of bars forward while they were raised, and backwards while lowered to carry
forward the burning fuel or small coal z to the back end A*, as before described,
where it would be delivered as burned into a back chamber Z111 for the
purpose, over the improved double or hollow bearing plate E, covered or
"fettled" with fire-clay, "ganister," or other fireproof material close under
the inner end of the fire-bars A, A¹, the outer edge of which would prevent
the admission of too much air at this part by the bars nearly touching them
in their lowest position, or when desired this plate E might be made to
carry the weight of the inner end of the reciprocating grate bars at E' in their
lowest position or when not raised at the inner end; and a door E" with long hand
rod El may be fitted below this hollow fireproof air-cooled plate E, for removing
the burnt fuel at intervals from the chamber Z111, between this and the back flame
wall Z³, that is, after the heat had been exhausted from it into the furnace flues along
with the other heated gases from the fuel on the grate; and when desired an
opening Z4 with or without a closing damper may be fitted through the lower part
of the flame wall Z³ to draw or conduct the heated spent gases from the burnt fuel
in the chamber Z111 to assist in the better utilization of these. In this arrangement
the fuel z is intermittently charged or fed on to the furnace bars A, A¹, from the
lower open end c of the hopper C at the front or mouth of the furnace Z over the
inner edge D' of the hearth or dumb plate D (secured some little distance above
the bars) by the reciprocating cross boxes, plates, or pushers G, having a sharp
angled or cutting edge G' across the upper front edge for the better separation of
each charge regulated by the length of "throw" or reciprocation given to each

page_text: 2
111
pusher, there being preferably two fitted to reciprocate or feed into each furnace
alternately, filling the space between the lower end of the hopper C and plate D
supporting and guiding them, and each actuated by short oscillating levers g carried
and fulcrumed on a centre pin and snug g' on the front end A³ of two of the long
reciprocating furnace bars A 5 and A' 12, which reciprocate alternately in opposite
directions, and so reciprocates the pushers or feeders G by the oscillation of the
upper free end g₁l of each lever g working in a slotted snug or other equivalent
connection with the pusher at g¹, the lower end of the lever g swivelling loose by.
its lower open forked end g¹ on the shaft F as a stationary centre, which always
brings the pusher G to its extreme back "throw." A pinching screw g³ is fitted in
the lower forked arm g¹ll to regulate the length of the forward stroke and conse-
quent amount of fuel fed in at each action, as particularly seen in Figure 2, and
the enlarged side and edge views of this feed lever action g, Figure 7; other
equivalent means may also be adopted for so reciprocating each fuel feeder or pusher
G by one of the elongated furnace bars A or A', as seen in the enlarged section
Figure 2G, by passing the lever g through a slot in the elongated end A¹¹¹ of the
bar A. fitted with a regulating pinching screw g³ and connected to the pusher G by
a slot and pin at g₁ or other equivalent connection. Or otherwise the levers g
might be carried on fixed fulcrums g¹ on the plate D, and oscillated by reverse
"throw" cranks ƒ³, g², or eccentrics on the shaft F as shown in the modification in
the front and side views in Figures 8 and 9, all so as to actuate the pusher G by a
roller in the upper end g¹¹ of the lever g and deliver a certain regulated amount of
small coal or other fuel z filled into the hopper C over the hearth plate D, D', on to
the furnace or grate bars A, A', below, to be burned and carried forward on these,
all otherwise as before stated. A narrow channel C" with slide door Ca in front is
formed over the hearth plate D, D', between the central guide cheeks, Cll of the
pushing feeders G for admitting air in front and inspecting the state of the fires or
combustion to enable the attendant to alter the rate of feed by hand of the fuel, or
of the admission of air also at the back E" of the furnace bars when that is desired
as will herein-after be explained. The first motion or revolving cam shaft F (which
actuates the whole of the bars A, A', and shafts and pushers B, G, and their gearing
in the improved manner as described) is actuated at a slow speed through a belt Y
passed round or over the cone pulley I (revolving loose on the strong stud F" in
one of the standards F¹) from a reverse cone pulley on any convenient over head or
other suitable motive-power transmitting shaft, and by a spur pinion I' on the cone
I gearing into the wheel 11 of the intermediate speed-reducing wheel and pinion I"
and I revolving on a hollow axis on a stud F secured in the side frame F¹, this
latter I gearing into the wheel 13 revolving loose on the shaft F, which it actuates
differentially as will be explained by the double gab coupling i, i, cast on the
outer side of this wheel Is, through its sliding or engaging and disengaging clutch i¹
fitted to the outer end of this shaft F with a groove and feather all as seen
particularly in Figure 1, and in detached end views and sections of the parts i, i,
of this coupling in Figures 14 and 15. The outer sliding part of this differential
driving coupling clutch i, i, is formed with a sliding sleeve or cap i on its outer
end, which when tightened up close by the end screw as shown in Figure 15,
forms a double collar groove for the vertical forked arm 3 of its engaging and
disengaging lever i³ and i to work in, both fulcrumed on one centre in the carrying
bracket j, and which keeps it into or out of gear with its actuating clutch i by and
according as the weighted arm I' of the lever is tilted to the horizontal position
shown in sharp black lines, or the opposite angular position shown in dotted lines
in Figure 1. By screwing back the end screw ill and cap i" so as to widen the
groove
12 and leave the lever, i, as shown in Figure 1, it will keep the clutch box
into gear with its driver i, so that the shaft F will work at the same speed as the
wheel I, and its clutch i are driven as the lever though moved would only
which
oscillate in the wide groove * formed by the screwing back of the cap ill,
would drive the stoking gear at the full maximum speed given by the wheel
gearing Ito 1 But when the shaft F is desired to make only half a turn-or

page_text: revolution for each revolution of the wheel 13 and its clutch box i, this is effected
by the semicircular or curved cam rim'i on the face of the clutch i, which ench
time it comes round acts on a projection on the lower end of one branch of the
forked lever ³, and so takes the clutch out of action with the clutch i when the
cap and screw ill are screwed up as shown in Figure 15, for half a turn of each
revolution of the clutches i, but allows the weighted lever,, to put and keep
the alternate gabs of the clutches into gear for the other half of the revolution;
that is, after and while the cam projection is on the clutch i ceases to act on the
lever ³, thus giving only half speed and motion to the stoking gear and feeding in
of the fuel.
Figures 10 and 11 show a sectional side view and a plan to a large scale of the
long furnace bars A or A¹ with the recessed heads A2, by which the whole set are
reciprocated through the duplex eccentrics fand f' on the cam shaft F, shown in
corresponding side and plan view in Figure 6. While Figure 12 shows a side
elevation of one of the short furnace bars A of the set, joined by the snug and
cross bars a, a, below; but it will be understood that both sets might be so joined
below when that was found more convenient; and it is preferred to make these
bars A, A¹, deeper than ordinary bars, with side webs a³ and an air space in the
centre as a, or partially of a hollow air duct or chamber shape, as seen at the
extreme back ends a³, with inlet and outlet air openings a, a¹¹¹, for the air to pass
through, either partially or throughout their whole length, as seen at a', all, a³,
and indicated by the arrows in the several Figures, so as to heat the air and keep
the bars cool and prevent them from burning. And the bars might be formed with
a groove or roughened on the upper surface a* and tapered away at the sides below
to admit the air and allow the ash to fall down through either with or without the
strengthening feather a, indicated in the large scale transverse section, Figure 13.
Although in these Figures, as so far described, both sets of the furnace bars A and
A¹ of each furnace have been described as reciprocated and raised while moving
forward, it will be understood that one set might be left stationary and that only
the other set would be so reciprocated and which would be raised above the
stationary set while being moved forward, and lowered below then while being
drawn back, in which case they might be raised and lowered only at the front end,
which could be effected very simply by mounting the front end of their two long
moving bars A2, A3, on single or double cranks f' on the first motion shaft F, as
shown in the side and end detached views, Figures 8 and 9, and which would
make a very simple arrangement, with only fixed bearing bars below the furnace
bars instead of the rocking shafts B and B¹, shown and described in the other
Figures. This direct reciprocating motion might also be made to give the raising
and lowering motion to the bars direct at the front end by making the eye or slot
A³ in which the cranks f2 work, or the space through which the moving connecting
rod works when that is used, less than that due to the upward "throw" of the
crank or rise of the connecting rod, so that as these come round to the top they
would always raise the bars in front just before carrying them forward to feed in
the fuel, as before described. The sliding supply door c¹ of the hopper C, instead
of being hung by chains and a counterweight c, as shown, it might be hung and
actuated by connecting rods at each side to connected bell cranks or other balanced
cranks with a single moving hand lever at one side, so as to be able to raise and
lower or push this sliding door c' up or down within the fuel hopper C to regulate
the admission or supply of fuel, a fixing quadrant being fitted to the hand lever for
securing the whole in any desired position. In some cases the upper end g¹¹ of the 5
lever g may be connected by a pushing and drawing rod passing through the
vertical webs G₁ of the pusher G, with regulating screw and jamb nuts on either
side of the webs to regulate the throw or stroke of the pusher G to deliver the fuel
on to the furnace bars, which rod might be actuated direct by a vertical stud or
kneed arm projecting up from the elongated heads or ends A2 of the bars A or A¹, 5
which would thus actuate the pusher G direct without a lever g when desired. Or
any other equivalent or ordinary intermittent or constant differential regulating
N

page_text: mechanical feed motion may be employed for feeding the fuel into the furnace, such
as a simple sliding plate instead of the feeding box or pusher G, fitted close over
the hearth D, with a hinged or folding down part at the front edge which as reci.
procated forward would fall and deliver the coal or fuel on to the grate bars A, A²,
over the front edge D' of the front dumb plate D, and which might have.a
strengthening feather below, and both coated on the inner surface next the fire with
fire-clay, ganister, or other fire-resisting material D*, and when desired, fitted on
the outside at D with a hinged or sliding door capable of closing down to near the
upper, front surface of the furnace bars A, A¹, for regulating the admission of air to
the furnace and fuel at this part, or for the insertion and working of a poker, rake,
or other fire-dressing implement below the dumb plate D, when desired.
When the sliding or pushing-in fuel feeder G and dumb plate D, D', below the
hopper are dispensed with the lower front sliding door of the hopper may be
brought down close to the highest level of the furnace bars, and to prevent the
escape of small coal through the front end of the bars when lowered each bar
might have a loose end or arm jointed to it in front, carried on a roller or other
equivalent below, so as to bear up against the front edge. of the hopper, and pre-
vent the escape of the fuel, while the bars themselves were lowered and drawn
backwards, or otherwise angular comb plates might be hinged to the lower front
edge of the hopper to rise and fall with the bars, and so prevent the escape of the
small coal or fuel.
Figures 16 to 24 on Sheet 2 are sectional elevations of boiler furnaces and their
furnace bars, showing slightly different modifications of my Invention or improve-
ments from those on and described in reference to Sheet 1 of the Drawings.
Referring to Figure 16 this shows an arrangement in which the furnace bars A
and A¹ are each formed with a short knee bar d, d', projecting by a stem or other
equivalent a short distance up from the top surface of the main bar at the front
end, so as to answer for and dispense with the separate fuel feeding hearth D, D',
and pushers G, G'. The highest and front vertical kneed part d¹ works close up
to the hopper C, and so answering as the pushers G, while the level part & answers
as a moving hearth to carry forward the dross delivered on to it under the hopper,
and deliver it over the inner edge at d on to the upper or grate surface of the
bars A, A', at every forward motion, and air is passed under or through the bars d
to their delivery end d¹¹ to thus assist the combustion of the fuel as delivered,
and on which it is fed forward and burned, the waste ashes being delivered over
the back or inner end A* of the bars into the back chamber Z, all otherwise
substantially as herein-before described in reference to Figures 1 to 3 on Sheet 1.
And when it is found desirable to retard the delivery of the incandescent fuel
over the back end A* of these raising and lowering and reciprocating furnace
bars A, A, Figures 1 to 3 and 16, as when the furnace is short or the fuel is found
not sufficiently burned when it reaches the back bridge E, they may be formed
with a raised or upwardly inclined part on the top of their back end, as shown
dotted in at A*, in Figure 16. Figure 17 shows an arrangement of the furnace
bars A and A', formed all one length and mounted between the ordinary heärth
plate D in front, and the back bridge or wall box Es suitable for hand-stoked
furnaces, but mounted on my improved arrangement of rocking shafts B, B', with
the arms b², 61, which raise the one set A or A¹ parallelly while lowering the other.
In this case by a hand lever B in front shipped on to a stem or into a socket
formed on the lever B¹ of the front rocking shaft B so as to break up and clear
the fire over the whole surface of the grate occasionally, as found desirable. The
back bridge E³ is shown as made or cast in the form of a hollow or close metal
box, through which the air is admitted at the back by the valve Ell, and led up a
front channel to the top and down a chamber e behind a division plate e' through
holes e" in the back wall E, all as indicated by the arrows, which arrangement
both beats the air and assists the combustion of the gases, and prevents the box
from getting so hot as to melt; but when desired this air box E may be covered
in front as well as above with fire-brick at e¹¹¹ to prevent this overheating, as seen

page_text: .
08
at Figure 18, which is a much similar arrangement to that shown in and described
in reference to Figure 17, except that the division plate e¹ in the air-heating
chamber bridge E³, e, is dispensed with, and a short stationary set of furnace
bars Zx is fitted between the back end of the raising and lowering bars A, A³, and
the air admission or back flame bridge Es, e. Figures 19 and 20 show a sectional
elevation and end section of a steam boiler and furnace Z, Z', as fitted with an
improved arrangement of water-heating metal box or low bridge H, fitted behind
the back end of my improved stoking furnace bars A, A¹, and ash delivery.
chamber Z, with the water led into it by a branch pipe H' fitted at the lower
part of the furnace flue Z¹, with a range of smaller pipes h led up from it,
and forward over the furnace bars A, A, where they are jointed to a larger
cross pipe h¹ jointed to each side through the furnace flue Z' high up, a
seen in Figure 20, so as to give a good circulation of the water through
the whole, and retard or break up and abstract much heat from the flames and
hot gases of combustion at this hottest part of the furnace, and which might be
added to any of the improved arrangements shown in Figures 1 to 3 and 16, instead
of or in combination with the back wall Z or behind the air-heating bridges E in
the arrangements shown in Figures 17 and 18. Figure 21 shows an arrangement
of hand raising and lowering furnace bar A, A', similar to that described in reference
to Figure 17, or it might be Figure 18, but with a duplex air and water heating
and circulating flame bridge E4, having the air box e below, with its regulating
valve El in front, and distributing holes e" behind, and the water bridge H above,
with its inlet branch H below, and one or more outlet vertical pipes / on top, led
up and jointed to the top of the fire chamber flue Z' to complete the circulation of the
water and absorb the heat from the flames and gases at this hottest part of the
furnace, and prevent the burning of the bridge or the formation of slag or clinkers
on it, which would obstruct the raising of the bars. Figure 22 shows a sectional
elevation of a double length set of my improved construction and arrangement of
furnace bars A, A', suitable for long furnaces, having the front set A³ mounted over
the back set A, with a stem on the lower back end of the front bars A³ projecting
down into a somewhat longer slot in the front end of the back bars A4, all sup-
ported on three rocking shafts B, B1, B*, so as to be worked, and raised, and lowered
substantially as described in reference Figures 1 to 3 on Sheet 1, and also recipro-
cated by the front set of bars A³, but these only give, a partial reciprocating
action to the back set of bars A* proportionate to the difference of their motion and
the play or shifting space left in the slot for the pushing or drawing and con-
necting stem of the front bars, which by their motion deliver the burning fuel on
to the back set of grate bars, which from having less motion retain the incandescent
fuel longer on them until quite burned before delivering it into the recess Z
behind. The bars in this Figure 22 are shown of the hollow box shape for receiving
and conducting the air through them, as indicated by the arrows, escaping into the
fire-place in a heated state at all11
Figure 23 shows a detached elevation of a mechanical motion somewhat different
from that herein-before shown or described for simultaneously raising and lowering
either or both of the alternate sets of bars A and A' in the same furnace, either at
the front end only, as indicated, with the back ends A* all resting on stationary
bearings E (or it might be at both ends by duplicating the arrangement and con-
necting them by rods and levers as B", 6", in Figures 2 and 14). This arrangement
consists of a rocking spindle or centre B carried in bearings in the lower part of the
fire-chamber Z' below the grate bars A, A¹, or in the ash-pit, oscillated by a single
lever b' by hand, or it might be automatically by a connecting rod 6s, 63, and cam 6111
on a cam shaft F, the bars A, A', resting on two sets of supports b* respectively, or
it might be alternate notched plates projecting up from the levers b, b¹, on the
shaft B, with the points of the supports or projections taking into steadying rounded
notches or angled centres with little friction, which would enable the alternato
sets A. and A¹ to be raised and lowered more easily than by the numerous bearing
arms b and b¹ shown in Figures 1 to 5 and 16 to 22. It is to be observed however

page_text: that in all these arrangements the weight of the one set of bars A always balances
the other set A', so that it is only the friction of moving the working parts and
fuel on their top that has to be overcome. But to lessen even this friction the
furnace bars A and A¹ might when desired be mounted on antifriction rollers,
pulleys, or wheels L at the back and front end, or as a carriage L*, preferably loose
on their common spindle L, and under one or both sets of the bars, as shown in
detached elevation in Figure 24, and rolling on smooth plates or rails L" below;
which could be raised and lowered during the inward feeding and outward or return
motion by any simple reciprocating lever action, such as that described for the
other raising motion by a cam, and rod, and lever, as 6111, 62, 63, and 64, Figure 23.
Other simple means may be adopted of driving the first motion cam shaft F of my
said improved mechanical stoker than that shown and described by straps, and by
reversed stepped cone pulleys and toothed wheels I, I, I, Figures 1 to 3; as by an
endless driving band or rope conveyed from a distant driving shaft, and passed over
a grooved pulley I* on a spindle as K, Figures 25 and 26, which show a detached
ond view and plan of driving by a simple arrangement of a properly turned groove,
and transmitting raised grooved friction wheels K, K', K", the first of which, K, is
secured on the same spindle or axis Kas the driving band pulley I* is actuated, and
being grooved gives motion to the second friction wheel K', which has its angled
rim working right in it and in the corresponding grooved wheel K", which would
either be on an axis K³, the same axis as the clutch i on the shaft F, to drive it, or
that of intermediate speed-reducing wheels I", Is, Figures 1 to 3; a simple weighted
lever K (fulcrumed at K2 in the side frame F¹), with double or forked link K',
drawing and retaining the transmitting or central friction wheel K¹ with sufficient
force into the grooved periphery of the wheels K and K as to drive the clutch i, i',
and cam shaft F and stoking machines, all as herein-before described, the lever Kli
acting as an engaging or disengaging hand lever when desired. Figures 27 and 28
are a side elevation and plan of an arrangement of duplex ratchet wheels as O, O¹,
on the same axes O, O¹, as the toothed wheels O", 0%, respectively, and gearing into
the central wheel 0111 on the central or intermediate spindle ol, all for giving and
regulating any desired slow regular motion to the cam shaft F of these improved
mechanical stokers, through its clutch i, i¹, before referred to, and which would be.
on the same axis as one of the wheels 0%, 0, 0, and driven from any near
overhead or counter-motive revolving shaft, as P, from an eccentric P¹, or
crank on it, through a connecting rod P" with adjustable screw and hand
wheel P, with collars P³, Pil, at its lower end, embracing the free ond of
a duplex-armed lever P fulcrumed on one of the axes o of the ratchet wheels
0, 0, and carrying pawls p, p, on its opposite arms working into the teeth of
these ratchet wheels O, O', so as to turn one or more teeth at a time in the
same direction, as indicated by the arrows, on both the up-and-down stroke of
the ratchet lever P, the stroke or throw of the lever P' being varied by a screw
wheel P to any desired slow speed, or even stop the motion of the lever P¹
all together, according to the distance or "play" left between the collars P³ and P111
for the arm of the lever P, and through whichever axis o, o³, or o¹¹ is connected to
actuate the clutch box i, i¹, thus actuating the cam shaft and stoker at the slow
regulated speed transmitted through it by the lever P' and its pawls p, p'. Other
arrangements of gearing may be adopted for driving the first-motion revolving shaft
at various speeds, such as through cone drums with shifting belt, or special small.
portable engines fitted near or attached to the framing of the stoker, and driving
the revolving shaft through the said cones and straps, or it might be by reducing
speed wheel gearing. The strap belt being shifted on the cones, or the speed of the
engine regulated by the pressure of the steam in the boilers through some of the
modifications of damper regulating apparatus in use, such as that of "Auld's
self-acting damper," shown in Figure 29 on Sheet 2 of the Drawings; the chain q
shifting the belt to increase the speed of the stoker as the float Q descended, and
vice versa, decreasing the speed as the float ascends by the pressure of steam and
height of water in the float-column Q¹; or the throttle valve of the engine or its
"

page_text: link motion may be shifted by the lever and rod r, rl, of the pressure regulating
valve or piston R, shown in Figure 30 on the same Sheet of Drawings. Instead of
using a single eccentric or cam shaft F, as herein-before described, for reciprocating
and lifting the sets of bars A and A¹ direct, a rocking shaft might be used with
duplex-armed levers projecting upwards and downwards from it connected direct,
or by links, or short connecting rods to joint eyes projecting up and down from the
ends of two of the respective sets of side bars instead of the large eyes A³ for
embracing the eccentrics f. fl. And this rocking shaft might be actuated by a con-
necting rod and lever from a crank on a revolving shaft driven at various speeds by
the motive-power gearing, or by the differential coupling, as shown and described in
reference to Figures 1 to 3, and Figures 15 and 16 on Sheet 1 of the Drawings,
which revolving shaft may be placed at any convenient position on the framing of
the stoker, as in front below the furnace flue Z' of the stoker, and the bearing
shafts B, B¹, for raising and lowering the bars, may either be actuated from the said
rocking shaft direct by rods and levers or by this extra revolving shaft through the
cam band by rods such as 611, b.
་
But when the transverse shafts B, B', below. the furnace bars A, A¹, are made to
revolve they are formed with opposite short raising and lowering projections or cam
pieces set alternately at opposite angles under each alternate bar, so that as the
shafts revolve and these cam pieces come round under their respective set of bars,
they raise the entire odd numbers of the bars as a set at one time, while the others
or even numbers are at their lowest position, or being lowered, so as to be
reciprocated inwards horizontally while raised, or in their highest position, and
vice versa, all otherwise as before described; either or both of these shafts B, B',
when thus made to revolve may be driven from the first motion shaft F when
it revolves, or from the said lower revolving shaft when this shaft F only
reciprocates through or by pitch chain wheels on these shafts and an endless
pitch chain passed over them.
In regard to the arrangement of mechanical or automatic stoker, described in
reference to Figures 1 to 3, and Figure 16, it is preferred that when the revolving
shaft is stopped to give a difference of speed and feeding-in of the fuel and motion
to the bars A, A1, that the shaft F is stopped so as to leave both sets of bars in the
same level plane during the pause. And it is also to be understood that only half,
.or one set of the alternate bars A or A³ may be reciprocated, although both sets are
raised and lowered. And when only one set A or A¹ of bars is reciprocated and
raised and lowered, or raised and lowered only, as might be the case in the hand-
stoking arrangements, Figures 17, 18, and 21, the weight of one half of the set A
or A raised might be made to counterbalance the weight of the other half, the one
half falling as the other half is rising, and although these improved automatic and
hand-stoking arrangements have only been shown as applied to flue-furnace steam
boilers, it will be understood that they are equally applicable to other forms of
steam boiler furnaces and furnaces generally, having furnace or grate bars ranged or
built within the brickwork, in which case the sides of the furnace close to the furnace
bars might be formed of water-circulating boxes, or air admission perforated plates
built into the brickwork.
'In these modifications of automatic motive-power fuel stoking furnaces for steam
boilers and other purposes herein-before described, and in other such furnaces
heretofore in use, the fuel is generally fed in or forward from the front end of the
furnace, and therefore has to burn backwards in the direction opposite to that in
which the fuel is fed in, which has the effect, with such fuel as small dross, and t
when heavy firing is necessary, of causing and maintaining a smoky fire, but by
another improvement of this Invention the fuel is fed in automatically on to the
back of the furnace bars through one, two, or more conical or other tapered holes or
tubes passed through the upper part of the steam boiler or brickwork above the
furnace chamber and grate bars, as the case may be, and which lead and conduct &
the dross or other fuel from the feeding hopper and mechanism fitted above it (such
as that described in the former arrangement) to the front end of the furnace. By.

page_text: this means the "green" dross or fuel fed on to the sets of reciprocating.or other
moving furnace bars would be carried forward to the front end of the furnace and
boiler by the improved upward and backward motion of the bars, instead of their
upward and forward motion as before described, so as to deliver the burnt fuel or
ashes into a close chamber for the purpose at the front end of the boiler and furnace,
instead of at the back as before described, leaving sufficient room between this
chamber and the entrance to the ordinary ash-pit below the furnace bars for the
free admission of air thereto, to support the proper combustion of the fuel in the
furnace above the bars. The fuel in this case being kindled at the front of the
furnace would burn from this backwards towards and over the " green "coal or
fuel being fed in at the back end as before, stated, and thus more effectually evolve
the gases from the "green". fuel and burn them as they are evolved, thus burning
or preventing the formation of the sınoke or gases more thoroughly. When the
fuel feeding tubes are formed down through the upper part of the steam and water
space of the steam boiler, they might be. lined with fire-clay, bricks, or tubes, or
ganister" or other equivalent refractory material to prevent the burning of the
tube plates, or risk of explosions or accidents by the overheating of these.
Having now described the nature of my said Invention, and the mode and
means of carrying the same into practical effect, I would observe in conclusion that
I make no claim to the mere principle or operation of pushing in the fuel upon the
grate bars, or the mere raising and lowering or reciprocating of these, as this has
heretofore been effected by various arrangements of stoking mechanism, but 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,
"
"
•
First. The general construction or combination of the parts of the improved
automatic or motive-power stoking machines or mechanism for and their fittings to
steam boiler or other furnaces, substantially as herein described in reference to and
shown in Figures 1 to 3 and 16 of the accompanying Drawings, and the modifica-
tions thereof shown and described in reference to the other Figures.
Second. The giving of a simultaneous raising and lowering vertical motion
combined with a forward and backward or horizontal reciprocating motion
respectively, to the furnace bars A and A' (in sets alternately and segmentally), of
mechanical or automatic stokers, for feeding in the fuel to steam boiler or other
furnaces, and also the construction or combination of mechanism for effecting or
producing the said motions, all substantially as herein-described in reference to and
shown in the accompanying Drawings.
Third. The construction and arrangement of shafts (as B, B¹,) or other equivalent
under the bars moved by and in connection with a revolving eccentric, cam, crank,
or rocking lever shaft, as F, for giving the said simultaneous vertical raising and
lowering motion combined with a forward and backward or to-and-fro horizontal
reciprocating motion to the furnace bars of mechanical stokers for steam boiler or
other furnaces, all substantially as herein described in reference to and shown in
the accompanying Drawings.
Fourth. The giving of a differential intermittent revolving motion, with long or.
short pauses to the driving or cain shaft F by the differential coupling shown in
Figures 1 to 3, and 15 and 16, or by the ratchet mechanism, shown in Figures 27
and 28, for regulating the speed or motion of the bars and feeding in of the fuel, of
mechanical stokers for steam boiler and other furnaces, substantially as herein.
described in reference to and shown in the said Figures of the accompanying
Drawings.
Fifth. The regulating or controlling of the speed of the driving gear of these
improved mechanical stokers, or their special portable steam engines when these
are used, by shifting the belt on cone speed drums through the steam pressure
float arrangement, or by the regulating pressure piston or valve lever arrangement
controlling the throttle or inlet valve of the engine, respectively as described in
reference to and shown in Figures 29 and 30 of the accompanying Drawings.

page_text: Sixth. The making of these improved vertical raising and horizontal reciprocating
bars A, A¹, of the double web or hollow box form, either with or without a grooved
or roughened upper surface, substantially as and for the purposes or advantages
herein described in reference to and shown in Figures 10 to 13 and Figure 22 of
the accompanying Drawings.
Seventh. The construction and application to these mechanical stokers of a
hollow or double protecting and bearing plate E with open air cooling space between
them, under the inner ends of the furnace bars A, A¹, coated externally with fire-
clay, "ganister," or other refractory material for making them more durable than
such bearing plates have been as heretofore constructed, all substantially as herein-
before described and shown in the accompanying Drawings.
Eighth. The feeding-in of the dross or fuel by tubes or apertures through the
.boilers or the roof brickwork of the furnace on to the duplex raising and recipro-
cating bars of these improved mechanical stokers at the back end of the furnace
and feeding it forwards to the front end of the furnace, all substantially in the new
or improved manner and for the purposes or advantages herein specified.
'
In witness whereof, I, the said John Auld, have hereunto set my hand and
seal, this Twenty-sixth day of April, in the year of our Lord One thousand
eight hundred and seventy-nine.
Witness,
W. R. M. THOMSON,
Patent Agent,
Glasgow.
JOHN AULD. ·(L.S.)