Improved Apparatus for Rolling Plastic Material into Sheets.
Year: 1894

page_text: Date of Application, 8th Mar., 1894-Accepted, 5th May, 1894
Improved Apparatus for Rolling Plastic Material into Sheets.
;
I, JAMES HENRY MITCHELL, of Chestnut Hill, Philadelphia County, State'
of Pennsylvania, in the United States of America, Manufacturer, 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 especially to rolls employed for forming plastic material of
any kind, style or description, into a continuous sheet, and has for its object the
provision of sheeting rolls of simple construction, whereby adhesion of the material
being sheeted is absolutely prevented.
To attain the desired end, ny invention consists essentially in a sheeting roll
having in its periphery minute or microscopic grooves, and means for packing
absorbent powder into the same, whereby a roll is provided having its surface
composed of powdered material compressed between metallic walls; and my inven-
tion also involves certain other novel and useful combinations or arrangements of
parts, and peculiarities of construction and operation, all of which will be herein-
after first fully described, and then pointed out in the claims.
In the accompanying drawing,
Fig. 1 is a plan view of a pair of sheeting rolls, embodying my invention.
Fig. 2 is a vertical, cross-sectional view at line a-, of Fig. 1.
Fig. 3 is an end view of a fragment of a roll illustrating substantially the
relation of the retaining metal to the compressed absorbent material.
Fig. 4 is a portion of a roll showing circular depressions in its surface.
Fig. 5 is a like view, showing the roll as covered with wire gauze to form the
powder-retaining cavities.
Like numerals of reference, wherever they occur, indicate corresponding parts in
all the figures.
Heretofore in sheeting plastic material, absent powder to prevent adhesion
has been plentifully supplied to either the surface of the material to be sheeted or
to the surface of the rolls, or to both, substantially all of such powder being taken
from the rolls, and left upon the surface of the sheet in an excessive quantity. By
my invention this over-application of absorbent powder is obviated, and only a very
small quantity is used, while at the same time adhesion of the sheet to the rolls is
entirely prevented, and a perfect sheet is delivered. This is accomplished from the
fact that my rolls, when in use, have their surfaces which come in contact with the
material to be sheeted, composed of a surface of absorbent powder embedded,
packed and held between metallic divisions of the face of the roll, only a very
small portion of such powder being taken up by the plastic material as it is formed
into the sheet.
In the drawings, 1 is the main frame wherein the rolls, 2, are mounted, the
shafts, 3, of said rolls being provided with driving gears, arranged in the well
known manner. As illustrated in Figs. 1, 2, 3, 4 and 7, the surface of the rolls 2
are provided with minute or microscopic grooves said grooves extending at an angle
to the axis of the roll. Practice has shown that a width of about one thirty-second
of an inch is the most effective width to give such grooves, as if they be made
wider, the absorbent powder will not pack firmly therein, and be held by the metal,
but will be substantially entirely removed by the material being sheeted, or fall
from the roll as it revolves, thus defeating the very object which is gained by my
invention. When made the size indicated but a very small portion of the powder
is removed from my rolls. I do not limit myself to the grooves arranged as above
[Prins 77

page_text: described, as other forms of surface to the roll, such as is indicated in Figs. 5 and 6
will carry out my invention, but I have found the said grooves to be the most
satisfactory in operation.
4, 4 are chambers arranged to hold the absorbent powder, provided with lids, 5,
said lids being inclined so as to form a portion of the hopper 6 for receiving the
material to be sheeted. Each powder chamber 4, is provided near its bottom with
a flexible flap, 7, made of leather, or equivalent material, having one edge secured
to the outer wall of the chamber, the other edge resting upon the periphery of the
roll, thus preventing the working downward of the powder from the chamber, the
weight of the powder holding the flap in position.
Beneath lid 5 of the powder chamber is a movable side wall 8 of said chamber,
held in grooves, 9, in the main frame. The lower edge of the wall 8 is provided
with a shoe, 10, preferably made of hard wood, said shoe being shaped in cross-
section as particularly illustrated in Fig. 2, and resting upon the periphery of the
roll 2. The object of this construction is to force, pack, and rub the absorbent
powder firmly into the grooves or holders in the roll 2, as it rotates by the weight
of said wall 8.
When constructed and arranged in accordance with the foregoing description,
the operation of my improved sheeting rolls is as follows: The plastic material or
lump dough to be sheeted is placed in the hopper, and rests upon the rolls, made to
rotate in the direction indicated by the arrows, in Fig. 2. The lump dough is
compressed into a continuous sheet, and is delivered upon any approved form of
receiving belt, in the usual manner; the surface of the sheet is only slightly
powdered, by the small quantity of absorbent powder taken from the roll cavities,
and all adhesion to the rolls is effectually prevented. As the rolls continue to
rotate, the small quantity of powder which has been taken by the sheet, is auto-
matically renewed, being so forced into the microscopic holders that I provide on
the surface of the sheeting roll, which when in operation, has a compressing surface
constituted of a combination of absorbent powder and metal, the powder being so
firmly embedded as to have nearly the same resistance in sheeting power as the
metal itself.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim, is :-
:―
1. In a sheeting machine, a roll provided with microscopic grooves, or cavities,
in combination with means for compressing absorbent powder into said grooves or
cavities, whereby the surface of the roll is constituted of a combination of powder
and metal, substantially as shown and described.
2. A sheeting roll provided with microscopic cavities in its surface, in com-
bination with means for automatically supplying absorbent powder to said cavities,
substantially as shown and described.
3. A sheeting roll provided with minute holding cavities in its surface, in
combination with a chamber for supplying absorbent powder to the roll which.
forms the bottom of said chamber, and means for forcing the powdered material
from said chamber into the cavities of the roll, substantially as shown and
.described.
...
1
MASTE
ERNEST DE PASS,
Chartered Patent Agent,
78, Fleet Street, London, and 6, Victoria Street, Nottingham,
Agent for the Applicant.