IMPROVE- MENTS IN ARRANGEMENTS FOR IMPARTING MOTION TO THE GRATE BARS OF FURNACES."
Year: 1875

page_text: LETTERS PATENT to Thomas Holt, of Rochdale, in the County of
Lancaster, Engineer, and James Schofield, of Littleborough, in the
same County, Cotton Manufacturer, for the Invention of "IMPROVE-
MENTS IN ARRANGEMENTS FOR IMPARTING MOTION TO THE GRATE BARS OF
FURNACES."
PROVISIONAL SPECIFICATION left by the said Thomas Holt and
James Schofield at the Office of the Commissioners of Patents, with
their Petition, on the 4th November 1875.
We, THOMAS HOLT, of Rochdale, in the County of Lancaster,
Engineer, and JAMES SCHOFIELD, of Littleborough, in the same County,
Cotton Manufacturer, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN ARRANGEMENTS FOR IMPARTING MOTION TO THe Grate
BARS OF FURNACES," to be as follows:-
Our Invention relates to the fire-grates of "steam boiler" and other
furnaces, and has for its object to impart motion to the fire-bars or to

page_text: some of them at certain times, or whenever desired, in order to clear the
spaces between the bars for the passage of air to the burning fuel for
well-understood reasons. To this end we support the bars upon bearers
to which a rocking movement can be imparted, and we so form the
upper surfaces of the said bearers as that when rocked in one direction
from the central positions each alternate bar is lifted, and when rocked
in the other direction the intermediate bars are lifted.
In an arrangement we have devised for the said purpose each bearer is
cast upon a central steel bar, the ends of which form trunnions which rest
in bearings. The upper surface of each bearer is cut away at intervals
from about the centre to each side so as to form notches or hollows in the
bearer, the notches on one side being opposite to the projections left
between the notches on the other side, so that each alternate fire-bar
rests upon the projections on one side of the bearer, the intermediate bars
resting upon the projections on the other side thereof. When the
bearer is rocked the projections lift cach alternate bar, the notches
clearing the intermediate bars. The bearers are connected together by
means of links or rods so as to move in unison. The said bearers aro
caused to rock by the operation of opening or closing, or of opening and
closing the fire-door; as for example, the bearers may be caused to rock
in one direction when the door is opened, and in the other direction
when the door is closed, the door being caused to act upon a lever or
upon levers connected with the bearers or with the front bearer.
In some cases this arrangement may be dispensed with and the
bearers be caused to rock by means of a hand lever or by power derived
from a prime mover.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Holt and James Schofield in the Great
Seal Patent Office on the 4th May 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, THOMAS 30
HOLT, of Rochdale, in the County of Lancaster, Engineer, and JAMES
SCHOFIELD, of Littleborough, in the same County, Cotton Manufacturer,.
send greeting.

page_text: rest in bearings. The upper surface of cach bearer is cut away at
intervals so as to form notches or hollows in the bearer, the notches on
one side being opposite to the projections left between the notches on the
other side, so that each alternate fire-bar rests upon the projections on
one side of the bearer, the intermediate bars resting upon the projections
on the other side thereof. When the bearer is rocked the projections
lift each alternate bar, the notches clearing the intermediate bars. The
bearers are connected together by means of links or rods so as to move
in unison. The said bearers may be caused to rock by the operation of
opening or closing, or of opening and closing the fire-door or doors.
And in order that our said Invention may be fully understood, wo
have appended hereunto a Sheet of Drawings marked with letters of
reference, corresponding marks indicating the same parts in the various
Figures.
Referring in this place to the said Drawings, Fig. 1, drawn about one-
eighth of the full size, represents a vertical longitudinal section of the
furnace flue of a steam generator. In the said Figure a indicates the
fire-bars, and b, b, the aforesaid bearers.
Figs. 3 to 6, drawn about half size, illustrate the form and action of the
said bearers, Fig. 3 being a plan of a portion of a bearer; Fig. 4, a side
view of the same; and Figs. 5 and 6 end views thereof. Each bearer is
formed of cast iron and is cast with an internal steel rod c which
projects from each end of the bearer, and forms trunnions which are
mounted in suitable bearings or brackets, so that the bearer can
oscillate or rock on the axis of the said trunnions. This internal steel
rod may be dispensed with if not considered to be necessary, trunnions
being cast on or fixed to or in the bearers or other arrangements to
permit of the rocking motion being made. The upper surface of cach
bearer is formed with bearing points or projections d, e, upon which the
bars rest. In the example, the first, third, fifth, and seventh bars would
rest on the points d, and the intermediate bars on the points e.
remaining part of the upper surface of the bearer is sloped or cut away
from the inner edge of each bearing point towards the opposite side of
the bearer, as indicated by the dotted lines at A, so as to form notches
or recesses in the bearer. An arm is cast upon the lower side of each
bearer, and in these arms are fixed studs upon which are mounted a
connecting rod which connects the two bearers together, so that a
The

page_text: rocking movement imparted to one bearer is communicated to tho
other.
In some cases it may be necessary to employ more than two bearers
connected together so as to move in unison.
Figs. 5 and 6 illustrate the action of the bearers. When the bearer is
caused to swivel on its axis into the position indicated by Fig. 5, the
bearing points d are depressed, and the bearing points e elevated, the
consequence being that the bars resting on the points d are lowered
slightly, the intermediate bars being raised. When the bearer is moved
in the contrary direction into the position represented in Fig. 6, a
contrary effect is produced, the bars resting on the points & being raised
and the intermediate bars lowered. This movement of the bearers may
be derived from a hand lever or be otherwise obtained in any suitable
manner, but we prefer to connect the actuating apparatus with the
furnace door or doors in such a manner as that the act of opening and
closing the said door or doors will cause the bearers to rock to and fro.
Such an arrangement is indicated in Figs. 1 and 2, the latter Figure
being drawn to an enlarged scale, and representing a front view of a por-
tion of the furnace door and the actuating apparatus. The front bearer is
connected by means of a rod or link i with an upright lever k which is
fitted to swivel in a bracket fixed to the furnace front or dead plate.
A finger m is forged or fixed on the lower end of the joint pin n which
is arranged to turn with the furnace door o. To ensure that the joint
pin shall so turn, we prefer to form a square hole in the part of the
door hinge marked B, and to square the portion of the joint pin which
fits into this part. When the door is opened the finger m strikes the
upper end of the lever and moves it outwards, thereby pushing in the
rod i and causing the bearers to rock into the positions indicated by
Fig. 6. When the finger has moved away from the said lever the
bearers move back into their normal positions or thereabouts by reason
of the weight of the fire-bars. When the door is closed the finger m
again acts upon the said lever, but in a contrary direction, the effect
being that the bearers are rocked into the positions indicated by Fig. 6.
Figs. 5 and 6 indicate the extreme range of movement of the bearers or
thereabouts.
By suitably adjusting the parts the range of motion may be reduced
to any desired extent, or by increasing the depth of the notches between

page_text: Having now fully set forth and indicated the nature of our said
Invention and means whereby the same may be carried into effect, we
would have it to be understood that we claim,―
First. The bearers for fire-bars formed and acting substantially as and
for the purpose herein-before set forth and indicated.
Secondly. The method of actuating the said bearers, substantially as
herein-before set forth and indicated.
And, Lastly. The combination and arrangement of parts, substantially
as and for the purpose set forth and indicated herein-before and in the
accompanying Drawings.
In witness whereof, we, the said Thomas Holt and James Schofield,
have hereunto set our hands and seals, this Second day of May,
in the year of our Lord One thousand eight hundred and seventy-
six.
Signed and sealed by the said
Thomas Holt and James
Schofield in the presence of
EDWARD K: DUTTON,
Agent to the Patentees,
THOMAS HOLT. (L.S.)
JAMES SCHOFIELD. (L.s.)
3, Princess Street,
Manchester.