[0001] The present invention relates to a frame for metal doors.
[0002] Metal frames are known for metal doors consisting of a single piece of U-bent sheet
metal, connected to the masonry and comprising on one side the hinges and on the other
side the holes for the locks and for the hinges.
[0003] In fire door applications, and with the purpose of improving thermal insulation,
metal frames have been produced with doors consisting of two pieces of bent metal
which are joined together via a gasket of plastic material of lesser thermal conductivity.
[0004] By achieving this purpose, the heat insulation and cold insulation from one side
to the other of the piece of sheet metal is further improved.
[0005] This type of frame involves however considerable labour during installation, considerable
complication during production, and a high final cost of the industrial product obtained.
[0006] The objects of the invention are to eliminate these drawbacks by providing for doors,
a metal frame which can be produced simply and comfortably, which presents a very
low thermal conductivity between the inside and outside of the environment, and which
at the same time is of pleasant appearance from the outside.
[0007] These objects are attained according to the invention by a frame for metal doors,
as described in claim 1.
[0008] A preferred embodiment of the invention is further clarified hereinafter with reference
to the accompanying drawings, in which:
- Figure 1
- is a plan view of a piece of sheet metal for obtaining the frame according to the
invention, and
- Figure 2
- shows the frame obtained.
[0009] As can be seen from the figures, the metal frame for metal doors is formed starting
from a piece of sheet metal 2 which along a longitudinal band thereof is provided
with a plurality of apertures 4.
[0010] In the illustrated example, the apertures consist of slotted holes which can be formed
by removal or by expansion (cutting and stretching the material).
[0011] The piece of sheet metal is bent and U-shaped to form, by means of its arms, the
flanges 6 for connection to the masonry 8 and, by means of its base 10, two portions
12, 12' parallel to each other and to the edge 14 of the masonry and a central portion
16 which with the portion 12' forms a step acting as the striker for the movable door
leaf (not shown in the drawing).
[0012] In particular, at this step the piece of sheet metal is bent over to form a lip 18
obtained by coupling together two facing bands 20, 20', one 20 of which, namely that
closer to the side of the masonry, consists of the longitudinal band with apertures
4.
[0013] A gasket 22 of insulation material is interposed between the two bands 20, 20'.
[0014] From the aforegoing it is apparent that the frame according to the invention presents
numerous advantages, and in particular:
- a constructional simplicity achieved by the facility to form the apertured band during
the actual profiling stage,
- a low coefficient of thermal conductivity between the outside and inside by virtue
of the slotted holes 4 which substantially reduce the metal cross-section through
which the heat is transmitted,
- a pleasant appearance in that the apertured band is not visible from the outside,
- a lengthening of the path which the heat has to take in passing from the inside to
the outside of the profile.
[0015] Moreover, the insulating gasket 22 prevents contact between the band 20 comprising
the slotted holes 4 and the band 20' which faces it, so as to prevent the heat being
able to be transmitted by direct conduction in case of their contact.
[0016] The present invention also extends to other similar profiles in which thermal conduction
must be reduced between two parts of the profile in a direction perpendicular to the
profile axis, such as window frames, continuous façade profiles, or other construction
profiles.
1. A frame for metal doors and consisting of a piece (2) of sheet metal bent to U-shape
with its arms (6) fixable to the masonry and with its base (10) disposed parallel
to the edge (14) of the masonry, said base (10) being provided with at least one lip
(18) parallel to the base and facing the edge (14) of the masonry, said lip being
obtained by coupling together two facing ledges (20, 20'), at least one of which is
provided with a plurality of holes, an insulating gasket (22) being positioned between
said ledges characterised in that said holes consist of a plurality of rows of longitudinally offset slotted holes.
2. A frame as claimed in claim 1, characterised in that said holes are obtained by removal of material.
3. A frame as claimed in claim 1, characterised in that said holes are obtained by expansion (cutting and stretching the material).
