IMPROVEMENTS IN THE MEANS AND APPARATUS FOR EFFECTING FIRE PROOF SEPARATION OF THE STAGE AND PROSCENIUM IN THEATRES
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by John Imray at the Office of the
Commissioners of Patents on the 28th January 1882. A communication
from abroad by Karl Pfaff of Vienna in the Austrian Empire.
JOHN IMRAY of No. 28 Southampton Buildings Chancery-lane in the County of
Middlesex, "IMPROVEMENTS IN THE MEANS AND APPARATUS FOR EFFECTING FIRE
PROOF SEPARATION OF THE STAGE AND PROSCENIUM IN THEATRES." A communi-
cation from abroad by Karl Pfaff of Vienna in the Austrian Empire.
This Invention relates firstly to an improved construction of fire proof curtain
for the proscenium opening of theatres, secondly in the construction of a fire proof
framing for such curtain and thirdly, to hydraulic apparatus for raising and
lowering the curtain. The curtain consists of horizontal strips of sheet iron or
steel bent to a curved or trough shape, the hollow side or trough side being
presented to the proscenium. Each strip has at its upper and lower edge a narrow
flat flange by which the strips are rivetted together and to vertical strips or bands
suspended at intervals from a rail at top. Owing to the curved or trough form of.
the strips the greater part of the curtain is situated at some distance away from
the supporting bands which are consequently kept in a comparatively cool
atmosphere in the proscenium when the stage is in flames and are surrounded by
cooling current of air at all points but the comparatively narrow connection with
the curtain. To increase the said distance, metal blocks or distance pieces may be
inserted between the curtain and the supporting bands. Thus as each individual
strip forming the curtain is supported by the vertical bands, there is no strain put
upon the upper strips by the weight of the lower ones, and the curtain is con-
sequently not liable to give way when it becomes heated, but always receives
effective support from the cooled supporting bands. In addition to the above
advantages, the trough shape of the strips render the curtain very strong in a
transverse direction and also affords it perfect freedom to expand and contract
without straining the connections.
The framing consists of two flat side rails to which the curved strips are rivetted
by angle irons and which slide up and down in fixed metal guides. At top the

page_text: side rails, the top strip of the curtain and the supporting bands are all secured to a
horizontal framed bearer, which carries the suspending bolts by which the curtain
is raised and lowered and also an overhanging lip which when the curtain is in the
lowered position, hooks on to a strong horizontal supporting rail, or by preference
an overlianging lip and supporting rail is provided on each side of the curtain,
which rail or rails effectually support the curtain even when the wire ropes or
bands by which the curtain is raised and lowered give way from excessive heating.
The said rail or rails is or are carried by a strong hollow iron beam through which
water is made to circulate so as to prevent its becoming over heated. The rails
being made of trough shape and filled with sand, the lip or lips of the curtain in
dipping into the sand form an effectual gas tight joint at the top of the curtain,
preventing the passage of flames or air at that point. For effecting as nearly as
practicable a gas tight joint at the sides of the curtain, this is by preference placed
at a slight inclination so that its side rails bear against the one edge of the grooves
in which it runs.
The lower edge of the curtain carries an angle iron, the fat face
of which rests upon the stage and thus also closes the opening as nearly gas tight
as possible. The fixed frame work for the curtain consists of two hollow iron
columns that carry the before mentioned grooves for the curtain and that are
bolted to the proscenium wall, while at the upper ends they are fixed to the before
mentioned hollow cross beam that carries the supporting rail; water is also made
to enter the columns to keep them cool, such water supply to the columns and
transverse bearer being by preference permanently maintained, in order to prevent
the possibility of the turning on of the supply being overlooked on the occurrence
of a fire. In order to produce an effective circulation of the water on this taking
place, the columns and bearer are provided with openings closed by plugs of easily
fusible metal, so that on the heat rising sufficiently to melt the plugs the water
-will-escape-through-the. openings and fresh water will continually enter from the
supply pipes. If the water supply is only turned on when-n-fire-occurs-the-fusible.
plugs are not required, the water being allowed to issue through the openings,
which should be so arranged as to cause the escaping water to flow over the parts
that are exposed to hent.
The raising and lowering of the curtain may be effected by any suitable known
means, but by preference hydraulic apparatus is employed, consisting of a vertical
cylinder fixed to the proscenium wall at the side of the curtain, and having a
plunger working up and down through the lower end. A rod passing through
this plunger and through a stuffing box in the top of the cylinder, carries a cross
hend with a sheave of pulleys round which pass the wire suspension ropes or bands
each leading to a separate pulley above the curtain, so that the downward motion
of the plunger causes all the suspension ropes and with them the curtain to be
raised.
The supply of water to and its escape from the hydraulic cylinder is regulated
by an ordinary slide valve that governs a supply and an escape port in the
cylinder, and in order to cause the movement of the plunger and curtain to
commence and terminate gradually, the ports are provided with throttle valves or
cocks, the axes of which are connected by links and levers to an arm carrying a
roller working in a cam groove in a plate that is moved up and down by means of
side rods attached to the crosshead, the cam groove being so shaped as to cause
-the throttle valves to open very gradually, when the plunger begins its descent
and to close very gradually as it comes to the end of such movement, and vice versa
as regards the ascent. The escape throttle valve is made to fit sufficiently loose to
allow of the escape of steam from the cylinder when this becomes heated by fire.
The slide valve may either be worked by a hand lever, or by preference its rod is
connected to a piston in a small cylinder to the upper or lower end of which water
pressure may be admitted through two pipes which may lead to a point some
distance from the curtain, where the water pressure is admitted to the one or the
other by a two way cock or slide. The piston has projecting bosses on each side

page_text: fitting into corresponding recesses in the cylinder ends, the water in which acts as
a butter for gradually retarding the movement of the piston and slide at the ends
of the strokes. Throttle valves are also provided in the ports of the slide cylinder
to regulate the motion of the piston and slide.
The degree of preponderance of the weight of the curtain over the action of the
plunger of the hydraulic cylinder can be regulated by placing more or less moveable
weights on the lower end of the latter, or counter weights may be attached to the
raising and lowering ropes at any convenient points.
•
Although the curtain has been described as being raised and lowered from abovo
the stage, yet it may also be arranged below the latter, or it may be made to slide
in and out from the side.