AN IMPROVED STAIRCASE
Year: 1885

page_text: I, WILHELM JOACHIM WEGNER of 91 Potsdamerstrasse Berlin, W. in the
Kingdom of Prussia and German Empire Architect do hereby declare the nature
of my invention for "AN IMPROVED STAIRCASE" and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement:―
This invention relates to a fire-proof staircase provided with an insulating space,
and its object is to obviate the disadvantages arising from the use of the fire-proof
staircases made of iron or stone as heretofore employed.
Some of the most dangerous disadvantages of fire-proof staircases as now in use
have, in great conflagrations, being found to be the cracking or bursting of the
stone and cast iron steps after they had become hot and were cooled by throwing
cold water upon them, and particularly the practical impossibility of preventing
staircases, as hitherto constructed for the purpose of rendering them fire-proof,
from becoming red-hot, so that all such staircases would serve indifferently one of
their most essential purposes, that is to say, the enabling of the escape of persons
from a building on fire.
The staircase constructed according to this invention is intended to obviate all
the above-mentioned disadvantages inasmuch as the improved staircase, even in
case of a great fire raging directly underneath the same, cannot so readily become
hot, and will therefore remain passable for a greater length of time than fire-
proof staircases as heretofore constructed, while furthermore, it will allow of being
cooled by throwing on cold water without there being any danger of causing it
to burst.
The invention is illustrated in the accompanying drawing, in which
Figure 1 is a side view of part of the improved staircase, and
Figure 2 is a transverse vertical section thereof on the line xy, Figure 1.
The improved staircase is made of metal plates a, b, preferably sheet-iron, which
are bent, by any suitable means, to assume the form of the usual steps. The
plate a is arranged above the plate b, so that the said two plates will run parallel,
or nearly parallel, with each other and form between them a space c.
This space c, enclosed above and below by the plates a and b, may either be
filled with some solid insulating material, such as ashes, mineral wool, or the like,
or with some suitable insulating fluid, preferably atmospheric air.

page_text: The connection between the said plates is preferably formed by means of the
stays d d rivetted thereto at the bends or corners; and to the said stays the side
plates, or carriages, e may be applied by screws, rivets, or in any other suitable
manner. The said side plates or carriages, are preferably made of sheet-iron
plates, so that the balusters f may be screwed thereto. The surfaces of the steps
formed by the plate a may be covered with wood, india-rubber or the like,
as usual.
In case air is used as the insulating substance for filling up the insulating space c,
it is deemed preferable to allow the same to enter the said space near the lower
end of the staircase and to escape again from between the plates ab near the upper
end of the same, so as to cause the insulating fluid to circulate through the said
space from the lower to the upper end of the stairs. Furthermore, where air is
employed, partly or wholly, as the insulator, and where the carriage at the side of
the stays & is dispensed with and the staircase is inserted directly into the wall of
the building, air holes may be formed in the walls to allow the atmospheric air
from the outside to enter the said insulating space and to thus increase the said
circulation.
The new technical result which this invention is intended to attain, and which
consists in preventing the staircase from becoming unfit for use, either by getting
red-hot in case of a fire raging underneath, or by bursting the steps in case of water
being thrown thereon, is thought to be fully, and in every respect, obtained by the
construction hereinbefore described.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed I declare that what
I claim is
A staircase composed of sheet-iron or other suitable metal plates (a and b) so
arranged with regard to each other that an insulating space (c) is formed between
the same, the said space serving for the reception of some suitable solid or fluid
insulating substance, such as ashes, air, or the like, substantially as, and for the
purpose, specified.