M.B.H, a corporation organized under the laws of
Germany, of 43, Lehliderstrasse, Berlin-Weissensee, Germany, 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:—
The invention relates to the construction
of floor slabs, wall panels, pavement lights, windows and the like
in which discs or cylindrical bodies of glass are framed in ferro
concrete, the invention being concerned with moulds for moulding
the concrete by the usual method of placing the moulds on a moulding
board or in a frame or box, with the glass bodies upon them, and
pouring the concrete into the channels between the walls of the
moulds, so that after removing the moulds there is a concrete frame
consisting of ribs extending crosswise, enclosing openings in each
of which a glass body is held.
For making the concrete frame the moulds
preferably have a rectangular base, so that they can be set closely
together on the moulding board, but they have circular openings
corresponding in diameter to the glass bodies. Consequently the
configuration of the moulds must be one in which there is a
transition from square to circular outline.
The greater the depth of the ribs, the
less light can pass through such a structure, inasmuch as the ribs
intercept and reflect light, not all of which passes out of the
frame, but for adequate strength the ribs must frequently be of
substantial depth, as when there is heavy traffic on a floor of
which they form part.
The usual form of mould is one in which
the rectangular base merges, towards the circular opening, into a
rounded part in the form of a hollow, truncated cone.
According to our invention the illuminating
capacity of the structure is increased by using a mould with a square
base from which four sides rise to form a
hollow, truncated pyramid, but are outwardly concave and have
their top edges bent to form the circular opening, the meeting edges
of the sides being lengthened to make corners which make an obtuse
angle with the plane of the opening. The construction of the moulds
enables a greatly increased amount of light to pass through the
structure, inasmuch as pockets are formed at the corners of the
openings in which the glass bodies are held, and a large proportion
of the inclined light rays which would otherwise be intercepted are
able to pass freely through these pockets. This is of particular
advantage in the case of built-in, arched roofs, where the available
light is generally weak near the walls. The weight of the floor is
also reduced by the absence of concrete in the pockets, so that the
depth of the ribs can be reduced.
A portion of a floor or pavement light
constructed with the use of moulds according to the invention is
shown by way of example in the annexed drawings,
Fig. 1 being a perspective view thereof,
with a portion broken away at one corner.
Fig. 2 shows several moulds on a moulding
board, one of them partly broken away.
Fig. 3 is a bottom plan view of one of
Figs. 4 and 5 being, respectively,
sections on the lines A—B and C—D of Fig 3.
Figs. 6 and 7 represent portions of
the finished structure, in section on lines corresponding to the
lines A—B and C—D respectively of Fig 3.
Each of the mould members has a square
base a from which the four sides e rise to form, roughly, a
hollow, truncated pyramid, but with inward curves e¹
near the base (Fig. 4), so that at its lower part the mould is
outwardly slightly concave, and inwardly convex. The corners
f are, accordingly, acute angled.
For producing circular openings in
accordance with the shape of the