IMPROVEMENTS IN RENOVATING OR REPAIRING KNOTTER.OR STRAINER BOTTOMS USED IN THE MANUFACTURE OF PAPER AND IN THE TOOLS OR APPARATUS EMPLOYED THEREFOR
Year: 1871

page_text: LETTERS PATENT to James Robertson, of Lasswade, in the County
of Mid Lothian, North Britain, for the Invention of "IMPROVEMENTS
IN RENOVATING OR REPAIRING KNOTTER.OR STRAINER BOTTOMS USED IN THE
MANUFACTURE OF PAPER AND IN THE TOOLS OR APPARATUS EMPLOYED
THEREFOR."
"
Sealed the 12th September 1871, and dated the 21st March 1871.
PROVISIONAL SPECIFICATION left by the said James Robertson at the
Office of the Commissioners of Patents, with his Petition, on the
21st March 1871.
I, JAMES ROBERTSON, of Lasswade, in the County of Mid Lothian,
North Britain, do hereby declare the nature of the said Invention of
"IMPROVEMENTS IN RENOVATING OR REPAIRING KNOTTER OR STRAINER BOTTOMS
USED IN THE MANUFACTURE OF PAPER AND IN THE TOOLS OR APPARATUS EMPLOYED
THEREFOR," to be as follows, that is to say :-
The bottoms of knotters or strainers used in the manufacture of
paper consist of metallic plates with very narrow slits or openings

page_text: cut through them, and by the wear and corrosion due to the straining
action the slits or openings in a short time become too wide, thereby
necessitating their being replaced with new plates.
The object of the present Invention then is to avoid the necessity of
employing new plates after tho said slits or openings have become
worn, which is effected by certain tools or apparatus which enable
the slits or openings to be reduced or brought back to their required
width.
The tools or apparatus consist of a block or anvil shaped to correspond
to the under side of the knotter or strainer plates, so that the plates
when laid thereon rest wholly upon the block or anvil, and to which
additional steadiness is or may be given by bolts or wedges. The slits or
openings are closed together to the required width by inserting into
each such slit or opening a tool formed with a feather at its lower end,
corresponding to the required width of slits or openings, which, being
struck by a hammer or pressed when so inserted brings the edges of
the slits or openings together, the impact or pressure causing the metal
at the edges to yield in the direction whereon it is free to do so, namely,
towards the fcather.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Robertson in the Great Seal Patent Office
on the 21st September 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, James
ROBERTSON, of Lasswade, in the County of Mid Lothian, North Britain,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of March, in the year
of our Lord One thousand eight hundred and seventy-one, in the 35th
year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said James Robertson, Her special license.
that I, the said James Robertson, my executors, administrators, and
assigns, or such others as I, the said James Robertson, 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 termi

page_text: "
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 "IMPROVEMENTS
IN RENOVATING OR REPAIRING KNOTTER OR STRAINER BOTTOMS USED IN THE
MANUFACTURE OF PAPER, AND IN THE TOOLS OR APPARATUS EMPLOYED THEREFOR,'
upon the condition (amongst others) that I, the said James Robertson,
by an instrument in writing under my hand and seal, should par-
ticularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, 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 James Robertson, do hereby declare
the nature of my 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 bottoms of knotters or strainers used in the manufacture of paper
consist of metallic plates with very narrow slits or openings cut through
them, and by the wear and corrosion due to the straining action the
slits or openings in a short time become too wide, thereby necessitating
their being replaced with new plates.
The object of the present Invention then is to avoid the necessity
of employing new plates after the said slits or openings have become
worn, which is effected by certain tools or apparatus which enable
the slits or openings to be reduced or brought back to their required
width.
The tools or apparatus consist of a block or anvil shaped to correspond
to the under side of the knotter. or strainer plates so that the plates
when laid thereon rest wholly upon the block or anvil, and to which
additional steadiness is or may be given by bolts or wedges. The slits
or openings are closed together to the required width by inserting
into each such slit or opening a tool formed with a feather at its lower
end corresponding to the required width of slits or openings, which
being struck by a hammer or pressed when so inserted brings the edges
of the slits or openings together, the impact or pressure causing the
metal at the edges to yield in the direction wherein it is free to do so,
namely, towards the feather.

page_text: And in order that my said Invention may be properly understood, I
now proceed more particularly to set forth the system, mode, or manner
in or under which the same is or may be used or practically carried into
effect, that is to say :-
Upon the Sheet of Drawings hereunto appended, Figure 1 is a plan;
Figure 2 is a longitudinal vertical section upon the line A, B, Figure 1;
and Figure 3 is a transverse vertical section upon the line C, D,
Figure 1, shewing a strainer or knotter plate A, and the method
whereby under my Invention it is secured upon an anvil or block B,
when the reduction of the width of the slits is being effected; Figure 4 1
is an enlarged transverse sectional view of a part of the strainer or
knotter plate A, and anvil or block B, also shewing in end elevation
the tool a, and feather 6 thereof, Figure 5 being a side elevation of the
tool a and feather b.
Under my Invention when the slits or openings c in the strainer
plate A have become too wide from usage as shewn at the side
marked 1, Figure 4, the said strainer plate A is placed upon the anvil
or block B, and secured thereto by means of the cramping frames C,
and pinching screws d, and also by the holdfasts e, and wedges f. The
anvil or block B is formed with grooves g, into which the ribs h of
the strainer plate A enter when placed thereon, thereby allowing the
flat portions of the under side of the said plate A to rest solidly upon
the top of the anvil or block B, and after being secured thereto in the
manner now set forth the operator inserts the feather b, which is
attached to the lower end of the tool a into one of the slits or
openings c, the parts of the tool on either side of the feather bearing
on the plate A at the edge of the said slits or openings c, and by
the impact of a blow or series of successive blows upon the head of the
tool a, the metal of the plate A at the edges of the slits or openings c is
forced inwards to the edge of the feather b, which reduces the said slit or
opening to the width required; the complete reduction of the width
of one slit c having been thus effected the operation is repcated upon
the whole of the remaining slits or openings upon the strainer or knotter
plate A, after which the said strainer or knotter plate is removed from
the anvil or block B, and is then in a state for use..
Having now described the nature of my said Invention and the
system, mode, or manner in or under which the same is or may be
used or practically carried into effect, I would observe in conclusion

page_text: that what I consider novel and original, and therefore claim as the
Invention secured to me by the herein-before in part recited Letters
Patent is, lessening or reducing the width of the slits or openings
in worn knotter or strainer plates so as to render the same again fit
for straining paper pulp, and the means or apparatus for effecting the
same as herein-before described and shewn upon the annexed Sheet of
Drawings.
In witness whereof, I, the said James Robertson, have hereunto
set my hand and seal, this Nineteenth day of September, One
thousand eight hundred and seventy-one.