Improvements in the Manufacture of Prismatic Glass Refracting Means.
Year: 1898

page_text: Date of Application, 3rd Dec., 1898
Complete Specification Left, 4th Sept., 1899-Accepted, 7th Oct.,
1899
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Prismatic Glass Refracting
Means.
I, FREDERICK THOMAS BREARLEY, of Hawarden Villa, Prescot Road, St. Helens,
in the County of Lancaster, Engineer, do hereby declare the nature of this inven-
tion to be as follows:
Heretofore prismatic glass refracting surfaces have usually been obtained by
means of small squares or blocks of suitably formed glass produced by pressing
molten glass in moulds, a number of such pieces being held together by framing
to obtain the required area such framing having the drawback of partly obstructing
the available light.
Now this invention has reference to improvements in the manufacture of
prismatic glass refracting means and has for object to produce glass plates of
any desired area one side of which is plane and the other side suitably formed
as a prismatic refracting surface.
According thereto plates of the desired dimensions are formed by means of
a table having accurately formed on its upper surface ribs or projections and
grooves of desired form. For example one side of each projecting rib or pro-
jection may be at or approximately at right angles to the plane of the table,
whilst the opposite side is inclined thereto so as to form a groove of desired size
and prismoidal form.
This grooved table may be of steel or other suitable metal and of any con-
venient size. It is placed on the slab of the rolling mill over which a roller
or rollers is or are drawn by mechanical means, the said roller or rollers being
adjustably arranged above the grooved table to enable the required thickness of
sheet to be produced. The prismoidal grooves and ribs or projections are pre-
ferably disposed parallel to the motion of the pressing roller or rollers. The
rollers or one of them is made sufficiently heavy so that by rolling over the
molten mass of glass placed upon the table the said glass is firmly and evenly
pressed into the grooves in the table so as to fill them. It is sometimes advan-
tageous to employ a second or following pressing roller in order to apply further
pressure to the rolled plate. The plate when sufficiently set is removed from the
table by sliding it thereupon or otherwise and is treated in the usual manner.
By these means glass plates provided with prismatic projections can be obtained
of any convenient dimensions.
It is to be understood that the angles of the grooves or corresponding ribs or
projections also the pitch and depth thereof may be varied according to require-
ments without departure from the essential features of this invention.
Dated this 3rd day of December 1898.

page_text: Improvements in the Manufacture of Prismatic Glass Refracting
Means.
I, FREDERICK THOMAS BREARLEY, of Hawarden Villa, Prescot Road, St. Helens,
in the County of Lancaster, Engineer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement:-
Prismatic glass refracting surfaces for diverting and distributing light have
heretofore usually consisted of small squares or blocks of suitably shaped glass
produced by pressing molten glass in moulds, a number of such squares or blocks
being held together by framing to obtain the required area. Such framing has
the drawback of partly obscuring the available light.
Now this invention has reference to improvements in the manufacture of
prismatic glass refracting means and has for object to produce glass plates of
any desired area one side of which is plane and the other side suitably formed
with ribs to form a prismatic refracting surface, the sides of such ribs being
inclined to form the desired angles of incidence and emergence for the rays of
lights falling upon and emerging from such sides.
According thereto glass plates of the desired dimensions are formed by means
of a table over which is passed a plain pressing roller, the said table having
accurately formed on its upper surface ribs or projections and intervening
grooves of the desired shape into which molten glass of suitable consistency
is pressed by the roller so as to form a plate having at one side a series of longi-
tudinally arranged prism like refracting ribs. For example one side of each
rib or projection on the table may be at or approximately at right angles to the
plane of the table, whilst the opposite side of such rib is inclined thereto so as
to form grooves of the desired size and shape.
In the accompanying drawings Fig. 1 shows partly in side elevation and
partly in longitudinal section, a rolling mill suitable for producing glass plates
in accordance with this invention. Fig. 2 is a plan, and Fig. 3 an end elevation
of the said machine. Fig. 4 shows, to a larger scale, and in cross section, part
of the table with its ribs and grooves and the lower part of the pressing roller
together with the rolled glass between these parts. Fig. 5 is a similar view
to Fig. 4 but with ribs and grooves of a slightly different angle. Fig. 6 shows
a detached view of the pressing roller connected with an embossing roller.
A is a suitable framework which supports a table B made of suitable thickness
to prevent warping. This table may advantageously be made of forged steel
having a close grain that will admit of its upper surface being highly finished
and rendered perfectly smooth. The upper surface of this table is grooved
longitudinally from end to end and for the required width. The grooves C
may be of various shapes, for example as shown in Figs. 4 and 5, which illus-
trates the most suitable angles for the two sides of each prism for ordinary
refracting glass although the angles may be slightly varied according to the
refractive index of the material or in case the emergent rays are to be directed
at a different angle, the two sides of each rib C, in the examples shown, being
inclined at different angles to the plane of the table. The size and pitch of the
ribs and grooves can also be varied to suit different requirements. Near each
edge of the table B there are provided removable gauge bars D, D which form
tracks of suitable height, the thickness of the bars employed being varied accord-
ing to the thickness of the glass plates required. On these bars a heavy plain
roller E bears and travels along, the said roller being kept thereby at a suitable

page_text: distance above the upper points of the prism-shaped ribs C according to the
thickness of the body part of the refracting glass plate to be produced. At the
outside of the gauge bars D, D there are provided toothed racks F, F with which
engage the teeth of the spur wheels G, G fixed to the opposite ends of the roller E
whereby the latter is caused to travel in a direct line with the table when rotated
by means of the projecting handles H or spokes of the traversing wheels J, J,
or by other suitable means. The roller E is made of such weight that by rolling
over the molten mass of glass placed on the table B in front of it and between
the adjustable guide K K, which is moved forward by the roller, the glass will
be firmly and evenly pressed into the grooves in the table B, so as to fill them.
The other side of the refracting glass plate may be left with the fire polish on it,
or it may be ground and polished, etched, treated with sand blast, or ornament-
ally embossed by another roller as may be desired. Previous to the rolling
operation, the table and roller are heated to a suitable temperature to prevent
chilling of the glass. If it be desired to produce an embossed pattern on the
upper surface of the rolled plate, a second or trailing roller E, as shown in
Figure 6, is or may be connected by links E2 to the axis of the main roller E,
the pattern being formed on the periphery of the smaller roller. After the
roller E has passed forward over the molten glass and rolled the same into sheet
form, it is allowed to remain at the end of the table to which it has been moved
and the rolled plate is carefully lifted from the table, a strip of metal or other
material being passed between the table and the rolled sheet so as to quickly
remove the latter from the grooves in the table. The roller is then moved back
to its original position ready for the next rolling operation. The glass plate is
treated in the ordinary manner in an annealing furnace. Prismatic plate glass
made as described I term "refrax" or "refraxo" glass.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is:-
The manufacture of rolled glass plates having a flat surface at one side and
prismatic ribs at the other side as set forth molten glass being rolled by means
of a heavy plain roller or rollers into grooves of the desired prismatic shape in
cross section formed in a table over and at a suitable distance above which the
said roller or rollers is or are caused to travel, substantially as hereinbefore
described with reference to the drawings annexed.
Dated this 4th day of Santambon 1000