Improvements in Fireproof Floors, Roofs, Girders, Joists, and the like.
Year: 1892

page_text: PROVISIONAL SPECIFICATION.
Improvements in Fireproof Floors, Roofs, Girders, Joists, and
the like.
I, JOHN HOLMES BLAKESLEY, of 39, Victoria Street, in the City of Westminster,
Civil Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to improvements in fire-proof floors, roofs, girders, joists
and the like, to be used in conjunction with a Patent granted to me No. 20,740,
bearing date November 20th, 1891.
The fire-proofing material is divided into arches resting on skew backs stepped
or unstepped, or the said arches may rest directly on the flanges of the joists
without skew-backs. The skew-backs if used are supported by the flanges of
the girders or joists and they (or the spring pieces of the arch if there are no
skew-backs,) have a limb passing round under the joist to meet or nearly meet
that from the other side of the same joist, the space between, if any, being filled
up by a filling tile or key. This limb may be close against the under side of
the joist or leave an air space between them. The main arch block or blocks
extend then from skew-back to skew-back or, where there are no skew-backs,
from joist to joist; but whereas when skew-backs are used the arch block between
may be in one piece, if there are no skew-backs, it must be in at least two pieces
to enable it to be put in after the iron joists are built in place
From skew-back to skew-back, or from joist to joist there also extends a flat
tile (generally keyed to hold plaster) which forms the ceiling of the room below,
and this flat tile under surface should be on a suitable level to make with the
under surface of the tile to keys below the joists the desired surface of the ceiling
beneath.
This flat tile may also be in segments, and it or its segments may be attached
to the arched limb above or its segments, by ties or joining pieces of any number
or position, thereby either leaving the space between the tile and the arch as a
single aperture, or dividing it up into any number of apertures of any shape.
The flat tile serves the purpose of holding the ceiling below, and also of pre-
serving such space or spaces between it and the arch for the purpose of ventila-
tion and lightening the floor.
The arched limb may form the top of the arched block or blocks, or there may
be as in my former Patent 20740 of 1891 another flat limb to make the whole
more nearly level on the upper side; and the whole may be covered or levelled
up with concrete, asphalte or any other suitable material. In the case of ware-

page_text: house floors where great strength is required, it is better to leave out such upper
flat limb of the arch block or blocks, and place concrete directly on the top of
the arched limb, as the concrete is thus formed into an arch which adds additional
strength.
On the arch where curve follows approximately the line of pressure, the con-
crete above also forming where it rests directly on the fireproofing arch, an
additional relieving arch.
My invention is constructed with suitable skew-backs grooved to receive the
flanges of the girder or joists, the same running parallel to and covering the
aforesaid girders or joists. Between the skew-backs or the joists I drop into
place the arched blocks, and between the bases of the said skew backs I attach
à flat tile, whose office is simply to support the plaster ceiling beneath, and also
to keep a large air space between the ceiling tiles and the arched blocks, by
which great lightness and powers of ventilation are secured.
If preferable the arch or flat tile or both together (with splayed ends) may be
made in one piece from skew to skew, resting on or between the skew-backs;
this said arch or block may be provided with struts or any shaped openings for
the purpose of ventilation and lightness, or this said arch can be divided into
two or more pieces with the ends grooved to rest on the flanges of joists, and
letting the main blocks spring straight from the joists without the use of skew-
backs, but in this case the block must be in at least two segments to enable it to
go in after ironwork is fixed. The joists between the segments of the arch
may be either plain, joggled, or keyed in any way. The arch blocks or skew-
backs, may be either solid or hollow, keyed or unkeyed and of any convenient
formation.
The fire-proof casing in all parts is made of fire-clay, terra-cotta, or any other
suitable fire-proof material, and the spaces are, where required, filled or levelled
with concrete in the usual way, or can be covered with asphalt or any other
material as desired.
It will be understood that the foregoing is given by way way of illustration
and that the shapes, materials, perforations, grooves, arches, skew-backs and
blocks, keys and tiles, or other parts, may be varied in many ways within the
scope of my invention.
Dated this 16th day of December 1800
J. P. BAYLY,
18, Fulham Place, W., Agent for the Applicant.
Improvements in Fireproof Floors, Roofs, Girders, Joists, and .
the like.
I, JOHN HOLMES BLAKESLEY, of 39, Victoria Street, in the City of Westminster,
Civil Engineer, 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 to improvements in fire-proof floors, roofs, girders, joists and
the like, to be used in conjunction with a Patent granted to me No. 20,740, bearing
date November 20th, 1891.
In the accompanying drawing the fire proofing material is divided into arches cr
blocks a resting on skew-backs 6 stepped or unstepped, or-the-said-arches-may-rest
directly-on-the danges of the joists-c-without-skew bucks-b;

page_text: The skew-backs if used are supported by the flanges of the girders or joists and
they (or-the-spring-pieces-e-of-the-arch-if-there-are-no-skew-backs b) have a limb f
passing round under the joist to meet or nearly meet that from the other side of the
same joist, the space between, if any being filled up by a filling tile or key. This
limb f may be close against the underside of the joist c or leave an air space between
them. The main arch block a or blocks extend then from skew-back b to skew-
back b, or-where-there-are-no-skew-backs,-from-joist-to-joist c; but whereas when
skew-backs-are-used the arch-block between-is-in-one piece, if there-are-no-skew-
backs, it must-be-in-at-least two-pieces-ns-indiented-by-dotted-lines-to-enable-it-to
be-put-in-after-the-iron-joists-nre-built-in-place.
From skew-back to skew-back, or-from-joist-to-joist in the arch block a are
grooves d keyed to hold the plaster to form the ceiling beneath.
The springing pieces and or arched limb e may form the top of the arched block a
or blocks, or there may be as in the former Patent No. 20740, of 1891, another flat
limb to make the whole more nearly level on the upper side; and the whole may be
covered or levelled up with concrete, asphalte or any other suitable material, but this
is no part of my invention nor do I claim it as such in this specification.
In the case of warehouse floors where great strength is required, it is better to
leave out such upper flat limb of the arch block or blocks, and place concrete directly
on the top of the arched limb, as the concrete is thus formed into an arch, which
adds additional strength.
The skew-backs b are grooved to receive the flanges of the girders or joists, the
same running parallel to and covering the aforesaid girders or joists. Between the
skew-backs er-the-joists we drop into place the arched blocks a, with groovesd
bottom d whose office is simply to support the plaster ceiling underneath; and also
with the arched surface above to keep a large air space between the ceiling and the
top of the arch, by which great lightness and powers of ventilation are secured.
The-arch block-may-be-made-in-one-piece-as-illustrated-in-the-drawing-from-skew
to-skew resting-on-or-between-the-skew-backs; the said block-being provided-with
struts-or-any-shaped-openings-for-the-purpose of ventilation and lightness,-or-this
said-arch-enn-be-divided-into-two-or-more-pieces-with--the ends-grooved--to-rest-on
the flanges of joists, and letting-the-main-blocks-spring-straight-from-the joists
without-the-use-of skew-backs.
The joists between the segments of the arch may be either plain or otherwise.
The arch blocks or skew-backs, may be either-solid-or-hollow, keyed or unkeyed
and-of-any-convenient formation.
The fire-proof casing in all parts is made of fire-clay, terra cotta, or any other
suitable fire-proof material, and the spaces, where required, filled or levelled with
concrete, asphalt or any other material.
I am aware that certain individual features in my design are not new in themselves,
but they have not been previously combined with other desirable features as in my
present invention; for instance an arched block has been devised before, which would
not however admit of the circulation of air as in mine. Another has been devised which
admitted of this circulation but did not protect the steel joists from it. A flat hollow
arch has also been devised, but which had no limb as mine to follow the curve of pressure,
and therefore puts undue strain on parts of the construction; and also being in many
pieces necessitates centring. The arched block in two pieces has also been devised as in
my Patent No. 20740 of 1891, to which the last objection also applies, this objection
being here obviated by the springing pieces or limbs at the end of the arched blocks
stepped on the skews so that even before the concrete is grouted into the crevices, the
ceiling is practically level below without centring
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 :-
4. In fire-proof floors, the combination of the hollow arch block a with struts and

page_text: springing pieces or limbs e, and the skew-backs b with the groove and limb f, and
joists, substantially as herein described and according to the accompanying drawing.
2. In fire proof floors, the combination-of-the-joists and-the-hollow-arch-in-two or
more-pieces-without-skew backs,-substantially-as--described-and-for-the--purpose
specified.
Dated the west 1
A
1000