Improvements in Furnace Grates.
Year: 1894

page_text: Date of Application, 22nd Oct.. 1894
Complete Specification Left, 25th June, 1895-Accepted, 10th Aug.. 1895
Improvements in Furnace Grates.
I, MICHAEL FITZ-MICHAEL MULREADY, of 7 Wentworth Place, Newcastle-
on-Tyne Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to the construction of vertically reciprocating furnace-bars
described in the Specification to my application for a Patent No. 13511 of 1894.
One of my present improvements has for its object to afford a support and guide
to the inner ends of the reciprocating bars and at the same time to insure that all
the bars shall be brought to the same level when released by their cams. For
this purpose I provide below such inner ends of the bars a transverse shaft carried
in bearings in the fire box, which shaft carries a series of plates that project up
into the spaces between the ends of the bars; each such plate has a shoulder
projecting beneath the bar next to it, so that the underside of the end of the bar
rests upon such shoulder. The shoulders of the consecutive plates are situated
alternately on opposite sides of the transverse shaft, so that as the end of the one
bar moves downwards, it presses downward the shoulder on which it rests, thereby
rocking the transverse shaft and causing the shoulder on the next guide plate to
rise with the rising end of the next bar, while when motion of the bars is reversed,
the shaft and plates are made to rock in the opposite direction, so the shoulders
always follow the bars in their up and down motion.
The above described arrangement may also be employed in combination with
any device other than that described in my said Specification for imparting the up
and down motion to the bars, but I prefer to employ for this purpose the following
arrangement.
In order to insure that both sets of bars shall always be at the same level at a
certain point of their motion, I provide at the front end, in addition to the cam
shaft that effects the downward motion of the front ends of the bars, a second
shaft below it receiving a rocking motion therefrom by any suitable means, and
having cam surfaces or arms that bear against an inclined surface formed on the
outer end of each bar or against the under surface thereof, so that after the outer
ends of the bars have been depressed, such cam surfaces are made to press them
upward again, by which positive motion the inner ends of the bars will all be
brought back to the same level.
The above described rocker supporting the inner ends of the bars may also
receive a positive rocking motion by any suitable means, for effecting the up and
down motion of the bars either in conjunction with cams operating on the outer
ends of the bars, or without the use of such outer cams. Such positive motion
may be imparted to the rocker by means of one or more excentrics on the cam
shaft outside the furnace or on a shaft geared therewith, which excentrics are
connected by rods to arms projecting froin the rocker.
Another improvement relates to the dead plates provided longitudinally on each
ide of the furnace to fill the space necessarily left between the bars and the sides
of the fire box. Such dead plates being subject to the intense heat of the fire,
re liable to deterioration, and in order to obviate this, I enclose the undersides of
he cavity beneath the plate with the exception of the front end, so that air can
here enter the flues, thus formed, from the ash pit. At the inner end the said
lues are made to communicate with a similar enclosed space under a dead plate
ID 077

page_text: at the fire bridge, which plate has an opening on the upper side through which air
can issue into the fire.
By the above described arrangement currents of air are set up through the
flues of the side dead plates to the opening in the end dead plate, and by such
currents the dead plates are sufficiently cooled to preserve them from injury.
In order to protect the upper surfaces of the fire bars against burning away,
I prefer to make such upper surfaces with a deep groove, having transverse ribs,
and I fill in such grooves with a suitable good non conductor of heat, which will
be effectually retained in position by means of the transverse ribs.
Dated this 22nd day of October 1894.
ABEL & IMRAY,
Agents for the Applicant.
I, MICHAEL FITZ-MICHAEL MULREADY, of 7 Wentworth Place, Newcastle-
on-Tyne, Engineer, do hereby declare the nature of this 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 relates to the construction of vertically reciprocating furnace-bars
described in the Specification to my Patent No. 13511 of 1894.
My present improvements have for their object to afford a,support and guide
to the inner ends of the reciprocating bars and at the same time to insure that all
the bars shall be brought to about the same level when released by their cams.
For this purpose I arrange such bars and mechanism in connection therewith
as I will describe with reference to the accompanying drawings, in which
Fig. 1 shews a longitudinal section of a furnace with rocking bars constructed
according to my invention; Fig. 2 shews an end view and. Fig. 3 shews a plan of
the same;
Figs. 4 to 9 shew enlarged details of two modifications of the rocking shaft
carrying the supports for the inner ends of the bars;
Fig. 10 shews an enlarged view of the cam shaft and rocking lever.
The bars A, which are arranged to rock on a fixed support B near their outer
ends, in a similar manner to that described in my said previous Patent, rest with
their inner ends upon the shoulders CC projecting alternately on opposite sides
of the shaft C and so arranged that the shoulders C¹ support, say, the 1st 3rd
5th &c. bars while the shoulders C² support the intermediate bars.
The front end A' of the bars project outside the furnace and are there acted
upon by cams or tappets D₁ on a revolving shaft D, the cams being so formed.
and arranged as to rapidly depress the outer end of every alternate bar, and then
to release the same. By such depression of the one set of bars, say those whose
inner ends rest on the shoulders C, the said inner ends are raised off the said
shoulders, and consequently the inner ends of the other set, which are free of the
cams D and which bear upon the shoulders C, will be free to descend by gravity,
and in depressing the shoulders C2, will partially rotate or rock the shaft C. on its
trunnions C³, suitably carried in bearings arranged on the sides of the furnace
chamber. The other set of shoulders C will consequently be raised so as to follow
the first set as they rise.
The construction of the rocking shaft C will be seen in Figs. 4 to 9, Figs. 4, 5
and 6 shewing respectively a side view, plan, ned cross section of one modification,
while Figs. 7, 8 and 9 shew similar views of another modification. These only
differ from each other in that in the arrangement at Figs. 4 to 6, a flange or
plate Cis made to project up between the consecutive shoulders, which flauges

page_text: serve as guides to the bars for keeping them laterally in position in their motion,
while in the arrangement at Figs. 7 to 9 the shoulders are hollowed out, the bars
being retained in position by resting with their rounded bottom surface in the
hollows, as indicated.
The bars may also be heid in position by passing through guides E provided at
the front end.
The cam shaft D, besides imparting the downward motion to the outer ends of
the bars, also effects the subsequent raising thereof, by imparting motion by means
of other cams or tappets D2 acting on tappets F' to a rocking lever or tappet F
projecting under the ends of all the bars, the cams D being so arranged that
immediately after the bars are released from the cams D' after being depressed
thereby, the cams D2 cause the lever F to move upward and thus to raise the
outer ends of the bars again.
It will be seen that at the middle position of the bars, both sets will be
practically at the same level, as the shoulders C C will themselves be level as
shewn on the drawing.
Although, I have shewn, by way of example, the rocking shaft C in combination
with the cam shaft D and rocking lever F, yet it will be obvious that it may
be employed in combination with any other arrangement for imparting the rocking
motion to the bars. The rocking shaft C may also have its motion imparted to
it independently of the bars A, by any suitable means, such as by eccentrics on
the cam shaft D or on a shaft geared therewith, which eccentrics are connected
by rods to arms projecting from the rocking shaft.
For preventing the side dead plates G of the furnace from becoming over-
heated 1, by preference, form closed air channels on their under sides which
communicate at their inner ends with a perforated box G¹ at the bridge, while at
their front ends they are open for the admission of air, so that by thus producing
an air draught through the channels, the dead plates will be kept sufficiently
cool.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what
I claim is -
1. In a furnace grate with vertically reciprocating bars such as is herein
referred to, supporting the inner ends of the bars by means of rocking supports,
arranged and operating substantially as herein described.
2. Constructing the rocking supports referred to in the first claim as a transverse
shaft having shoulders arranged alternately on opposite sides thereof in such
manner that by the downward motion of the inner ends of the one set of bars the
corresponding shoulders on the one side of the shaft are depressed, thereby partially
otating the shaft and causing the shoulders on the other side to rise and follow
be other set of bars in their upward motion, substantially as described.
3. Arranging the rocking shaft referred to in the second claim to receive a
ocking motion by suitable driving gear independently of the furnace bars
ubstantially as described.
4. In combination with a cam shaft for imparting motion to vertically reciprocating
urnace bars by means of cams so formed as to effect the rapid depression of the
uter ends of the bars and to then release the same, the use of a lever or tappet
perating on the undersides of the bars and actuated by the said cam shaft so as
raise the outer ends of the bars again after they have been released by the
aid cams substantially as described.
Dated this 25th day of June 1895.
ABEL & IMRAY,
Agents for the Applicant.