IMPROVEMENTS IN MACHINERY FOR ROLLING CAST GLASS
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Charles Arthur Allison at the Office of
the Commissioners of Patents on the 25th June 1878. A communication
from abroad by Louis Bonneville and Henri Joseph Mayan, Merchants, of the
City of Paris, in the Republic of France.
CHARLES ARTHUR ALLISON, of the Firm of Allison Brothers, Patent Agents, 41;
Southampton Buildings, Holborn, in the County of Middlesex. "IMPROVEMENTS IN
MACHINERY FOR ROLLING CAST GLASS." A communication from abroad by
Louis Bonneville and Henri Joseph Mayan, Merchants, of the City of Paris, in the
Republic of France.
This Invention relates to improvements in the machinery employed for rolling cast
glass. This has hitherto been effected in the following manner :-The molten glass has
been run on to a metallic table, upon which two adjustable longitudinal bars are
placed to regulate the width and thickness of the article or object to be manufac
tured. A heavy cylinder is then rolled over the glass and upon the bars, and by
its motion causes the glass to be evenly spread over the surface of the table. The
article thus produced is then withdrawn from the table, and polished if necessary.
This mode of manufacture has several important disadvantages,-
1st. The molten glass adheres firmly to the table, and necessitates a considerable
amount of skilled labour to separate them without breaking the glass, and further
requires the sheet, if to be used as plate glass, to be formed considerably thicker
than necessary in order to afterwards reduce it to the proper thickness by the process
of polishing, thus greatly increasing the cost of manufacture.
2nd. Tho difficulties experienced in this process increase with the size of the
articles, and restrict their inanufacture within certain limits.
3rd. This process can only be applied to a certain class of articles, such as mirrors
and other flat objects.
4th. It only allows a design to be applied to the side of the glass in contact with
the cylinder. If the table were employed to produce a design on the other side it
would become almost impossible to separate the glass from the table.

page_text: The object of this Invention is to obviate these disadvantages, and consists in
employing a rolling mill composed of two cylinders, placed one above the other,
and worked by toothed wheels driven by a crank or any other suitable means.
The bottom cylinder is fitted with two adjustable bands or rings, the thickness
of which will vary with the thickness of the article to be produced, and the distance
they are placed apart will determine the width of the same.
If desired both cylinders may be fitted with bands or rings, the thickness of which
will together be equal to the thickness of the sheet of glass.
The distance between the cylinders is regulated by adjusting screws.
A table to
receive the glass as it leaves the rolling mill is placed so as to almost touch tho
lower cylinder, and forms a tangent to the point of contact of this cylinder.
The rolling is effected in the following manner :-The bands or rings are first
placed at the required distance apart, and the cylinders adjusted by means of the
screws, so as to bring the bands or rings in contact with the cylinder, or with each
other if placed on both cylinders. The molten glass is then run out, and conducted
between the cylinders, which are immediately put in motion, and cause the glass
to pass through them to the opposite side at the required thickness, where it deposits
itself upon the table, and is carried forward. This table is perpendicular to a line
passing through the axes of the cylinders, so that if this line wore vertical the table
would be in a horizontal position, and the friction of the glass thereon would prevent
its sliding. The table should therefore be inclined so as to allow the glass to slide
freely, at the same time preventing it from being drawn out in length by its own
weight.
The table is composed of transverse parallel sections, attached to an endless
chain, which moving away from the cylinders as the glass issues from between them
is carried forward, the glass sliding on the table by its own weight.
It is necessary to regulate the temperature of the rolling cylinders in order to
produce a perfect article, and also to prevent an excessive expansion; the cylinders
are therefore made hollow so as to be either heated or cooled when working, their
journals being bored and fitted with a steam connection, through which is passed
a jet of steam, or any suitable hot or cold liquid or fluid.
The advantages resulting from this process are as follow:-
1st. The glass can be run directly to the thickness requisite; the table to receive
the molten glass being abolished removes the danger of breaking the glass in with-
drawing it, and limits the polishing process purely to the surface of the glass, thus
rendering it much less costly.
2nd. Articles may be cast of much larger dimensions, the only limit being the
longth that can be given to the rolling cylinders.
3rd. Not only flat glass, but all kinds of concave or convex glass can be cast
with mouldings or designs on one or on both sides of it. The design, moulding or
curve to be produced sunk in on the surface of one of the cylinders in order to
obtain the same in relief, and raised on the surface of the cylinder in order to
obtain the opposite result.
4th. The operation is carried on more rapidly, as it is continuous, whereas in the
ordinary way one article has to be taken off the table before another can be cast.
5th. It effects a saving in material and workmanship.
In order to obtain articles with holes in them the full part of the design is sunk
into the surface of one of the cylinders, the bands around the cylinders abolished,
and the two cylinders placed in close contact.