COMPOSITE PROFILE,A BASIC METAL PROFILE TO BE USED FOR MAKING SUCH COMPOSITE PROFILE,AND A METHOD OF MAKING SUCH A COMPOSITE PROFILE

Abstract: A composite profile, a basic metal profile and a method for making said composite profile, said composite profile comprising two metal members (1, 2) held apart from each other by means of two insulating bars (3) which have been cast in situ and thereby fixed in grooves between flanges (5, 6) on the metal members, said composite profile being made from a basic onepiece metal profile in which inner flanges (6) are interconnected in pairs prior to the casting thereby to form mold bottoms (4), said bottoms being split or removed after the casting of said insulating bars.

Description: Composite profile, a basic metal profile to be used for making such composite profile, and a method of making such a composite profile. The present invention relates to a composite profile, a basic metal profile to be used for making such composite profile, and a method of making such composite profile. The composite profile comprises two metal members which are held apart from each other and interconnected by means of at least two insulating bars which have been cast in situ and thereby fixed in grooves formed between flanges on the metal members. Such a composite profile and a method of making it are pre¬ viously known. By the prior art method is used a basic metal profile in which two of the outer flanges which contribute to define grooves are bridged to form the bottom of a mold for the casting of one of the insulating bars. This bar is cast from the inside of the profile. Following to this a mold bottom consisting of a thin foil is inserted between the two inner flanges which contribute to define grooves, and the second insulating bar is cast from the outside. After the casting the thin foil will be kept fixed between the flanges and the second insulating bar. There¬ after the bridging element is removed, for instance by planing, milling or tearing, and only the insulating bars and the foil remain to connect the two separate metal profiles which have thus been formed. It is an object of the present invention to provide a compo¬ site profile which has better insulating properties than the prior art profile. Another object is to provide a basic metal profile to ' be used for making such composite profile, said basic metal profile and said method resulting in improve¬ ments with respect to the insulating properties of the composite profile and advantages with respect to the manu¬ facturing of the composite profile. The composite profile of the present invention is characterize in that it partially is made from a single basic metal profile, the inner flanges of the profile being interconnected in pairs through bridging elements which together with the inner flange make mold bottoms for the casting of the insulating bars, said mold bottoms being at ' least split longitudinally of the profile after the casting. A basic metal profile according to the invention, preferably extruded, to be used for making the composite profile, is characterized in that the inner flanges are interconnected in pairs through bridging elements. A method according to the invention is characterized in that the insulating bars are cast in a single basic metal profile, in which the inner flanges are interconnected in pairs through bridging elements, which together with the inner flanges form mold bottoms during the casting, and that the mold bottoms are at least split lengthwise of the profile after the casting. In the prior art profile mentioned the walls of the metal profiles and the insulating bars define a hollow space. The heat transfer through the composite profile, in a direction along the insulating bars as seen in a cross section of the composite profile, takes place in the form of heat conduction in the insulating bars, heat convection in the air inside the hollow space and heat radiation between the inner metal surfaces. O FI ' Dur ng t e cast ng o t e nsu at ng ars n t e pr or ar profile there is only one bridging element, between one pair of outer flanges, which helds the metal profile together as a unit. Due to this fact the basis metal profile, especially when having a large dimension in the direction transversely of the bridging element, is unstable with respect to its shape, because only small forces are necessary to move the free edges of the profile towards or away from each other. Due to the small dimensional tolerances which the finished profile usually has to be within, particular precautions have to be made in order to prevent relative movements between the "legs" of the metal profile prior to and during the casting of the insulating bars. The basic metal profile used for making the prior art composite profile is half open, i.e. channel shaped, because a continuous opening runs between those flanges which define the grooves adapted for one of the insulating bars. By the anodizing of the basic metal profile prior to the casting of the insulating bars the metal profile will be anodized on at least a part of its inner surface. It is well known that anodized surfaces give a higher rate of heat transfer by radiation than un-anodized surfaces. It is, therefore, advantageous to avoid anodization of the inner surfaces, but it is necessary to anodize the metal on the outer surfaces. By use of the prior art profile this can only be achieved by anodizing after the casting of the insulating bars. At that stage the composite profile is fully closed, and anodizing of the inner surfaces will only take place a short distance inwardly from each end of the profile. The method, however, presupposes that the insulating bars are able to withstand the anodizing process. By the present invention may be achieved an improved resistance to heat transfer, both convection and radiation. In particular the convection may be reduced, by separating the bridging elements from one of the flanges and bending them into the hollow space. Alternatively the bridging elements may be split longitudinally along their central areas, whereafter the halves are bent into the hollow space. The bent bridging elements will then reduce the circulation of air and hence the convection. Ey means of a suitable ratio between the cross sectional dimensions in the hollow space may be achieved that the bridging elements bent into the space make ribs which act as flaps to slow down the air movements in the space. There should, however, be left at least a split between the bent halves of the bridging elements, or between the bent, complete bridging elements and the flanges on the opposite sides. When the basic metal profile is anodized prior to the casting of the insulating bars, it is of advantage with respect to the heat transfer by radiation that the bridging elements are completely removed, or that they are only slightly bent into the hollow space, because the anodized surfaces of the bridging elements will act as radiation surfaces. The fact that the elements protrude slightly into the space will still reduce the heat transfer by convection by slowing down the air movements, and at the same time is avoided that the bridging elements contribute substantially to heat transfer by radiation. A substantial advantage achieved with the present invention is the increased stability with respect to shape of the basic metal profile. Because the insulating bars are cast in situ the basic metal profile alone will determine the shape of the finished composite profile, and the present invention makes it possible to carry out the casting without specific pre¬ cautions to prevent cross sectional deformation of the basic metal profile prior to or during the casting. Further, the invention eliminates the need of a foil to make a mold bottom for the second insulating bar. According to the invention the heat transfer may be further reduced by providing some sort of strip between the insulating bars. This can be done both when the bridging elements are completely removed and when they are split and bent into the hollow space. The bending or removal of the bridging elements will then leave room for the strip, which is preferably only engaging the insulating bars. Thereby convection between the metal surfaces inside the hollow space is prevented, and provided that the strip is made of a material having a low heat conduc¬ tivity, the entire heat transfer between the metal surfaces may be substantially reduced, probably by about 30 % . More¬ over, the strip will cause a substantial reduction of the heat transfer by radiation. Calculations made for a given profile show that the application of a strip may cause a 50 % reduction of the heat transfer by radiation, in a profile having un- a,nodized inner metal surfaces, which gives a very small radiation transfer also without a partition strip. It is of advantage to the application of a partition strip that grooves are formed in the inner surfaces of the insulating bars, in order to secure the strip in its place. Such grooves may be formed in a simple manner, by forming the bridging elements with longitudinal ribs on the sides facing outwardly in the basic metal profile. By casting the insulating bars, these will consequently have grooves on their inner sides, complementary to the ribs on the bridging elements. This can not be achieved by the prior art method described introductorily, by which method the single bridging element constitutes a mold part for the outer surface of one of the insulating bars. The inner surface. of the same bar is formed as a free surface, by moving a spraying nozzle along the groove which forms the mold, said nozzle spraying insulating bar casting material into the groove. Thus, the present invention brings about a further possibility of reducing the heat transfer. In the following the invention will be described more in detail, with reference to the accompanying drawing, which shows embodiments of composite profiles in accordance with the invention. Fig. 1 shows an embodiments in which the bridging elements have been split longitudinally along their central areas, space in the composite profile. Fig. 2 shows an embodiment wherein grooves have been formed on the inner surfaces of the insulating bars, and a strip has been inserted and extends between the grooves. Equal reference numerals are used for equal or eqvivalent parts in the two figs. The composite profile shows in fig. 1 comprises two. metal members 1 and 2, which of course may comprise further details and parts than those shown, for instance channels for mounting of glass or sealing strips or for other purposes, depending on the application of the composite profile. The composite profile shown comprises two insulating bars 3, which have been cast in situ by use of the bridging elements 4 as a part of the mold bottom, which has been possible because the bridging elements connect the inner flanges 6 in pairs in the basic metal profile. In the finished composite profile the bridging elements 4 have been bent inwardly into the hollow space, and thereby cause a consider¬ able reduction of the heat transfer by convection. The metallic connection between the metal members 1 and 2 is completely broken, and heat transfer by conduction may only take place through the insulating bars 3. These have a very ■ small heat conductivity compared with metal. The insulating bars are fixed between the flanges 5 3nd 6 on each of the metal members 1 and 2. As mentioned, the insulating bars are cast in situ in a basic metal profile comprising two parallel bridging elements, whereupon the bridging elements, in this embodiment, are split longitudinally along their central areas and are bent into the hollow space. This splitting and bending may be carried out in one operation, by means of a tool which is forced OMFI longitudinally through the hollow space and splits and bends ■ the bridging elements, preferably simultaneously on the two sides, so that the metal profile is only subjected to free forces in the longitudinal direction, because transverse forces caused by the splitting and bending will then counteract and balance each other. The embodiment shown in fig. 2 also comprises metal members 1 and 2 and insulating bars 3, as well as flanges 5 and 6 which form grooves for the insulating bars. The insulating bars have grooves in their inner surfaces, and a partition strip 7 has been inserted into and extends between these grooves. In this embodiments the bridging elements have been removed completely, but they might alternatively have been bent sufficiently into the hollow space to allow the insertion of the strip 7. It is of course possible to provide more than one strip inside the composite profile. Such strip or strips may have a stiff¬ ness sufficient to make it possible to push the strip or strips into the profile, but it is also possible to pull the. strip or strips into the profile.

Claims: CLAIMS 1. Composite profile comprising two metal members which are held apart from each other by means of at least two insulating bars which have been cast in situ and thereby fixed in grooves formed between flanges on the metal members, c h a r a c t e r i z e d i n that it is partially made from a single basic metal profile, the inner flanges (6) of the profile being interconnected in pairs through bridging elements which together with the inner flanges form mold bottoms for the casting of the insulating bars (3) , said mold bottoms being at least split longitudinally of the profile after the casting. 2. Profile as claimed in claim 1, c h a r a c t e r i z e d i n that the bridging elements (3) are split mainly centrally between the inner flanges (6) , and that the halves of the bridging elements are bent inwardly about hinge lines situated in the transition bet¬ ween the bridging elements and the inner flanges. 3. Profile as claimed in claim 1, c h a r a c t e r i z e d i n that each of the bridging elements is separated from one of the inner flanges and bent inwardly relatively to the second inner flange, to which the bridging element is connected. 4. Profile as claimed in claim 1, c h a r a c t e r i z e d i n that the bridging elements have been removed after the casting. 5. Profile as claimed in claim 1 - 4, c h a r a c t e r i z e d i n that at least one partition strip (7) connects the insulating bars (3) , said strip or strips being inserted with its edges resting in grooves in the insulating bars. 6. Basic metal profile to be used for making a composite profile as claimed in claims 1 - 5, said basic profile having flanges which define grooves adapted for mounting of insulating bars by casting in situ, c h a r a c t e r i z e d i n that the inner flanges are interconnected in pairs through bridging elements. 7. Basic profile as claimed in claim 6, c h a r a c t e r i z e d i n that weakening grooves are formed in the transition between the bridging elements and the inner flanges. 8. Basic profile as claimed in claim 7, c h a r a c t e r i z e d i n that weakening grooves are formed longitudinally along the center areas for the bridging elements. 9. Basic profile as claimed in claims 6 - 8, c h a r a c t e r i z e d i n that the bridging elements are provided with at least one langitudinal rib on the sides facing outwardly of the profile. 10. Method of making a composite profile comprising two metal members which are held apart from each other by means of at least two insulating bars which are cast in situ and thereby fixed in grooves formed between flanges on the metal members, c h a r a c t e r i z e d i n that the insulating bars are cast in a basic metal profile having inner flanges interconnected in pairs through bridging elements which together with the inner flanges form mold bottoms during the casting, and that said mold bottoms being at least split longitudinally of the profile after the casting. 11. Method as claimed in claim 10, c h a r a c t e r i z e d i n that the bridging elements are split mainly in their central areas after the casting, and that the halves of the bridging elements are bent in¬ wardly about lines situated in the transition with the inner flanges. 12. Method as claimed in claim 11, c h a r a c t e r i z e d i n that each bridging element is separated from one of the inner flanges and bent inwardly of the profile. 13. Method as claimed in claim 12, c h a r a c t e r i z e d i n that the two bridging elements are separated from the respective inner flanges on opposite sides of the profile (i.e. at mutually opposite ends of the elements) , whereupon they are bent inwardly. 14. Method as claimed in claim 10, c h a r a c t e r i z e d i n that the bridging elements are removed from the composite profile after the casting. 15. Method as claimed in claims 10 - 14, c h a r a c t e r i z e d i n that it is applied a basic metal profile which has longitudinal weakening grooves at least in the transition between each bridging element and one of the adjoining flanges. 16. Method as claimed in claim 10 - 15, c h a r a c t e r i z e d i n that it is applied a basic metal profile which has at least one longitudinal weakening groove along the central area of each bridging element. 17. Method as claimed in claim 10 - 16, c h a r a c t e r i z e d i n that it is applied a basic metal profile which has at least one longitudinal rib on the side of each bridging element facing out on the profil OMP WIF

Inventors: GUDBRANDSEN H
Applicants: GUDBRANDSEN H, RAUFOSS AMMUNISJONSFABRIKKER, RAUFOSS AMMUNISJONSFAB AS
Application year: 1980
Main classification: E06B3
IPC codes: E06B3