DOOR, PREFERABLY FIREPROOF DOOR

Abstract: The object of the invention is to produce fireproof doors having two door panels (1 and 6) spaced from each other and having rectangular support inserts or bracing partitions (7-9) arranged between them. Rectangular blanks are used for the support inserts (7-9) and the edges to be brought into abutment with the inner sides of the door panels (1 and 6) are provided with transversely outwardly directed protrusions (11 and 12). The blanks (7-9) are placed between the two door panels (1 and 6) so that the latter abut the protrusions (11 and 12) and are perpendicular thereto. With the help of welding jaws (17 and 21) the two door panels (1 and 6) are pressed towards each other into abutment with the edges adjacent the protrusions (11 and 12), the protrusions (11 and 12) being simultaneously melted and thereafter solidifying to form binding welds (29 and 30).

Description: Door, preferably fireproof door The present invention relates to a metal door. Such doors can generally b used as fireproof doors and are manufactured from two flat plates space from each other and joined together by a surround of metal which ma consist of a strip arranged on edge- A number of bracing partitions are arranged in the space enclosed between the two metal plates. A bracing partition may have Z-shaped profile and be produced from a metal strip. The two parallel parts of the profile are located immediately over each other and the flange-like parts of the profile are provided all along with outwardly directed studs. These studs are converted to point-welds when the finished door is placed between two welding jaws. Due to the design of the bracing partitions and irregularities in the material, the metal plates forming the door panels may not be exactly flat after the welding process, which is a great drawback. The spaces between the internal partitions in the finished door are filled with filler material which may be sound-insulating, heat-insulating or have high thermal resistance. Of course, the filler material need not have only one of said properties. It may have two or more of the properties. The present invention aims at avoiding the drawback of the door panels not being completely flat after welding in the bracing partitions. This is achieved by using blanks for are completely rectangular for the bracing partitions, said blanks being provided with a number of transverse pro¬ trusions arranged one after the other on the edge surfaces to be brought into contact with the inner sides of the door panels. The blanks may be flat or corrugated but the transverse generatrix of the blanks shall always be straight. Such blanks are placed on edge between the two metal plates which are to form the door panels, in which a way that the blanks are pendicular to the internal surfaces of the metal plates. The metal plates are brought into abutment with the transverse protrusions of the blank. INAL The two metals plates which are to form the door panels are now pressed towards each other by means of two welding jaws, whereupon current will flow through the protrusions gradually melting them to provide said abut¬ ment. Each of the melted protrusions will form a weld on each side of each blank on the metal plate. Additional features of the present invention are revealed in the following claims. The present invention will be described more fully with reference to the accompanying drawings in which, Figure 1 shows the preparation of a door prior to welding, Figure 2 shows two welding jaws in contact with respective metal plates forming door panels and protrusions on a bracing partition, and Figure 3 shows how the two protrusions are converted to welding joints. In the figures 1 is a metal plate constituting one panel in the door to be manu actured. The metal plate is provided with two side walls 2 and 4, provided at the free ends with outwardly directed flanges 3 and 5, respec¬ tively. The two flanges 3 and 5 are designed to abut a metal plate 6 which is to constitute the other panel of the door. Three rectangular bracing partitions 7, 8 and 9 are placed on the metal plate 1. The bracing partitions have two longitudinal, parallel edges provided with transverse protrusions 11 and 12. These are equally spaced from each other along the longitudinal edges. The bracing partitions 7, 8 and 9, with their pro¬ trusions 11 and 12 are suitably punched out of sheet-metal. The bracing partitions 7-9 need not necessarily be flat. They may be corrugated, but under all circumstances the transverse generatrix of the bracing parti¬ tions must be straight. The three bracing partitions 7-9 are placed on edge on the metal plate 1. They will cherefore be in contact with the metal plate through the protrusions 12. 3oth the protrusions 12 and 11 are shaped to give point contact. Each protrusion increases gradually in width BAD ORIGINAL from the contact point to the adjacent edge. . The area of the protrusio may be triangular or have an arc-shaped periphery. The bracing partition 7-9 can be kept upright by means of suitable retaining members. In othe words, the bracing walls shall form right angles. In the present case suc members are not necessary since the parallelepipedic blocks 13, 4 > 15 an 16 which are to constitute filler material for the door can be used. O course the blocks may be given various properties. They may, for instance, be heat-insulating, sound-insulating or resistant to high temperatures. The blocks may of course have all these properties. They are placed as shown in Figure 1 and when the blocks are in place the bracing partitions 7-9 can be placed between them, held in upright position thereby. After this, transverse walls, not shown, with contact flanges may be arranged. Thereafter the metal sheet 6 which is to constitute the other door panel, is placed on top of the flanges 3 and 5, in contact with the protrusions 11 on the bracing partitions 7, 8 and 9. A press body 17 with three welding electrodes 18, 19 and 20 is placed on the upper side of the metal plate 6, the electrodes being located immediate above the bracing partitions 7, .3 and 9. The metal plate 1 rests on three welding electrodes 22, 23 and 24 located on a support 21. The welding electrodes 22, 23 and 24 are arranged immediately below the bracing partitions 7, 8 and 9. If current is now supplied to the welding electrodes it will pass with high current density through the protrusions 11 and 12 on the bracing partitions 7-9. The high current density causes the protrusions to start melting at the contact points. If the press body is held thus under pressure the metal plates 1 and 6 will gradually approach the longitudinal edges of the bracing parti¬ tions as the protrusions are melted. When the plates 1 and 6 are in contact with the longitudinal edges of the bracing partitions 7-9, the protrusions will stop melting at the same time as the welding current is cut off. The melted material of the protrusions forms welding joints on. each side of each bracing partition. Figure 3 shows the welding joints 29 and 30 on one side of bracing partition 7. It is clear from the above that a metal door has been successfully manu¬ factured in accordance with the invention, in which both door panels are perfectly flat. This is enabled thanks to the use of bracing partitions form angles of 90 with the two opposing metal plates which form the two panels of the finished door, and by giving the protrusions on the bracing partitions such a shape that they are gradually converted to welding joints.

Claims: CLAIMS Door, preferably fireproof door, wherein the opposing door panels consist of two metal plates (1 and 6) between which are arranged one or more support inserts or bracing partitions (7-9), each of which having flat surfaces abutting the inwardly facing surfaces of the two opposing metal plates (1 and δ) , the abutting surfaces being joined together by welding, preferably point-welding, characterised in that each support insert or bracing partition (7-9) consists of a rectangular, preferably flat sheet, placed perpendicularly to said two opposing metal plates (1 and 6), abutting them and secured to them by means of point-welding which has been achieved by the melting of transversely outwardly directed protrusions (11 and 12) from the abutting edges of the metal plates (1 and 6). Method of manufacturing a door according to claim 1, characterised in that the blank for each support insert or bracing partition (7-9) is manufactured from a sheet of metal in such a way that a rectan¬ gular, preferably flat sheet is obtained, the edges intended to abut the two metal plates (1 and δ) which are to form the door panels being provided with transversely outwardly directed protrusions (11 and 12), that the sheet (7-9) produced is placed between the two metal plates (1 and 6) which are to form the two door panels in such a way that the two metal plates (1 and 6) abut said protrusions (11 and 12) and that the generatrix of the sheet (7-9) which is perpen¬ dicular to said edges provided with protrusions is straight and perpendicular to said two metal plates (1 and 6), that the two metal plates (1 and 6) are -pressed towards each other by means of two welding jaws (17 and 21), the protrusions (11 and 12) being simul¬ taneously melted, so that the metal plates (1 and 6) come into contact with the edges adjacent the protrusions (11 and 12) and that the melted protrusions (11 and 12) are allowed to solidify to provide binding welds between the support inserts or bracing partitions (7-9) and the abutting metal plates (1 and 6). 3. Method according to claim 2 , . characterised in that each protrustioπ (7-9) is dimensioned so that its abutment against the relevant metal plate (1 or δ) is point-like and that its width gradually increases from the contact point to the adjacent edges of the protrusion.

Inventors: BERGLUND BERNT ELOF, GRIMSKOG STURE
Applicants: BERGLUND BERNT ELOF, GRIMSKOG STURE, NYKROPPAVERKEN AB
Application year: 1982
Main classification: E06B5
IPC codes: B23K11, E06B3, E06B5