The present invention relates to a frame for metal doors.
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.
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.
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.
This type of frame involves however considerable labour during installation, considerable complication during production, and a high final cost of the industrial product obtained.
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.
NI 1003 974 C2 relates to a frame for metal doors with the features of the preamble of claim 1, having a first wall section and on the longitudinal rims two wall sections at right angles. Bend rim stretches parallel with wall section. On the side of wall section , wall section is parallel with protruding wall section.
These objects are attained according to the invention by a frame for metal doors, as described in claim 1.
A preferred embodiment of the invention is further clarified hereinafter with reference to the accompanying drawings, in which:
As can be seen from the figures, the metal frame for metal doors is formed starting from a single piece of sheet metal 2 which along a longitudinal band thereof is provided with a plurality of apertures 4.
In the illustrated example, the apertures consist of slotted holes which can be formed by removal or by expansion (cutting and stretching the material).
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).
In particular, at this step the piece of sheet metal is bent over to form a lip 18 obtained by coupling together two facing ledges 20, 20', one 20 of which, namely that closer to the side of the masonry, consists of the longitudinal band with apertures 4.
An insulating gasket 22 of insulation material is interposed between the two ledges 20, 20'.
From the aforegoing it is apparent that the frame according to the invention presents numerous advantages, and in particular:
Moreover, the insulating gasket 22 prevents contact between the ledge 20 comprising the slotted holes 4 and the ledge 20' which faces it, so as to prevent the heat being able to be transmitted by direct conduction in case of their contact.
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.