CERTAIN NEW AND USEFUL IMPROVEMENTS IN PAPER MACHINERY
Year: 1867

page_text: LETTERS PATENT to Francis Curtis, of Newton, in the County of Middle-
sex, and State of Massachusetts, United States of America, for the Inven-
tion of "CERTAIN NEW AND USEFUL IMPROVEMENTS IN PAPER MACHINERY."
Sealed the 14th June 1867, and dated the 1st April 1867.
COMPLETE SPECIFICATION filed by the said Francis Curtis at the Office
of the Commissioners of Patents, with his Petition and Declaration, on
the 1st April 1867, pursuant to the 9th Section of the Patent Law
Amendment Act, 1852.
TO ALL WHOM IT MAY CONCERN, BE IT KNOWN, that I, FRANCIS
CURTIS, of Newton, in the County of Middlesex, and State of Massachusetts,
United States of America, have invented "CERTAIN NEW AND USEFUL IMPROVE-
MENTS IN PAPER MACHINERY," and do hereby declare the following to be a full,
clear, and exact description thereof, due reference being had to the accom-
panying Drawings making part of this Specification:-
For the sake of clear elucidation the Invention will be classed under several
heads, the first being a hard rubber roll for pressing, sizing, and callendering
paper.
In Figures 1 and 2 of the Drawings this roll is shown as composed of a
metallic body, a cylinder A, having journals a, a, formed upon it for duly
supporting it in position. This roll has an outer covering 6 of hard rubber
applied in a manner well known to those skilled in the art of vulcanizing
b

page_text: rubber. The body A of the roll should have a number of shallow longitudinal
grooves c, c, c, etc. at about equal distances apart cut in its periphery and
running from end to end thereof, the object of these grooves being to allow
the escape of the confined air which would otherwise cause blow holes in the
rubber. A sheet of paper or some kindred material is to be placed upon the
periphery of the roll and between it and the rubber shell to prevent slipping of
the rubber upon the roll.
The advantages which the above-described rolls possess over all others are,
first, they are slightly elastic, and press more evenly and thoroughly than other
rolls, consequently less steam and time are required for drying the papers.
Second, acids do not affect them, and they will not corrode nor become rough
like metallic rolls; with proper usage they will be as smooth after five years'
wear as when first used. Third, the paper will not stick to them as it does to
iron rolls; they can be easily kept clean by a "doctor" traversing them
laterally, made of hard rubber, which will not crease them. Fourth, felting
cloths will wear fully one quarter longer on them than on metal rolls. Fifth,
they are more economical than any other rolls. The first cost is but little
more than iron, and only about one-half the cost of brass rolls.
Another portion of my Invention, shown in Figures 3 and 4, relates to the
suction box of a paper machine, the construction and operation of which is well
known and understood by those at all conversant with the manufacture of
paper by the Fourdrinier machine, it being an oblong rectangular box provided
with a foraminous top, upon which the endless wire cloth apron carrying the
paper pulp travels, a vacuum being created within the box for the purpose of
creating a suction or draft upon and through the pulp and extracting the water
therefrom. As the construction of these vacuum boxes forms no part of my
Invention, which consists in the material of which it is composed, an elaborate
description of them is not necessary. The material now generally employed
in their manufacture, and to which there have been few exceptions, is wood
with a metallic top on account of its cheapness partly, but principally on
account of its lightness, as the box must frequently be removed from the
endless wire cloth and from the machine. Being constantly covered and
partially filled with water the wood swells and expands in different directions,
frequently causing them to leak, and always rotting them rapidly; in addition
to this the friction or abrasion between the metallic top of the box and the
wire cloth apron tends to wear out both rapidly. In my Invention, which as
before stated consists in constructing the box and its cover of hard rubber all
these objections are obviated. The box so made is water-tight, and un-
changeable at all times and under all circumstances, is comparatively inde-

page_text: structible, and is sufficiently light. It has been found in practice that the wear
between its top plate and the endless wire cloth is very much less than in the
old mode of construction, thus greatly economizing the cost of the wire cloth,
which is one of the heaviest items in the manufacture of paper.
Another portion of my Invention, which is a screen plate for paper machinery,
is shown in Figures 5, 6, and 7 of the Drawings, in which A denotes the body
of the plate, and a, a, a, the thin and narrow slots or saw kerfs through which
the paper pulp passes, and by this means is "screened" as it is termed, the
bars or portions of the body between the slots being shown at d, d, d, etc.
The body of the screen is chambered or recessed below each slot, as seen at 6
in the Drawings.
The above is the usual construction of screen plates, my Invention consisting
in constructing the said plates of hard rubber in place of the metallic ones now
used. The slots of the metallic plates in the operation of cutting them have
their lower edges left in a rough state or with a burr upon them; the threads
or fibres of the paper pulp in passing through these slots of the screen are
often stopped and collected by this rough edge or "burr," and clog or fill up
the slots, causing much inconvenience and loss of time in cleaning them.
Furthermore, the bars between the slots of the metallic screen plate in time
often become bent or out of vertical parallelism with each other, and enlarge
the area of the slots, so that the pulp passes through them in large quantities
and without being screened, an evil well understood by practical paper makers;
again the acid, contained more or less in the pulp or in its sizing, injuriously
affects the material composing the metallic plates. In addition to all these the
hard rubber plate can be manufactured at less cost than the metallic one, and
is much more durable.
In constructing the plate of hard rubber, as in my Invention, these evils are
overcome and other advantages gained, which will readily show themselves to
men practised in the art of paper-making, and to whom this Specification is
chiefly addressed.
First, owing to the peculiar nature of the rubber plates there is no rough-
ness or "burr" left upon the edge of the slots, whether they be cut by
machinery as the metallic ones are now cut, or whether they be formed by
pressure in a mould for vulcanizing.
Second, by the elastic properties of the rubber the bars will return to place
automatically, should they any time be forced out of parallelism with each
other, or otherwise misplaced or bent.
Third, the surface of the rubber is not in the least affected by the action of
acids.

page_text: In addition to these facts the hard rubber plate can be manufactured at
less cost than the metallio-one, and is infinitely more durable.
I claim the various improvements in paper machinery for the manufacture
of paper, substantially as above described.
In witness whereof I have hereunto set my hand and seal, this 12th
FRANCIS CURTIS. (L.S.)