GB1573032A

GB1573032A - Continuous production of composite sections

Info

Publication number: GB1573032A
Application number: GB1674577A
Authority: GB
Original assignee: Alusuisse Holdings AG; Schweizerische Aluminium AG
Current assignee: Alcan Holdings Switzerland AG
Priority date: 1976-04-23
Filing date: 1977-04-22
Publication date: 1980-08-13
Also published as: DE2625453A1; AT364523B; FR2348808A1; CH608978A5; CA1091565A; ATA278477A; DE2625453C2; FR2348808B1; IT1079582B

Abstract

Compound profiles comprising at least two metal profiles (P1, P2) and, between the latter, a (setting) plastic (S), in particular polyurethane foam, are produced by a process in which the metal profiles (P1, P2) are guided between mutually opposite, approximately synchronously revolving conveying means (3, 4) and in which the plastic (S) is introduced between the profiles by means of a spraying device (24, 25) before entry to the conveying means (3, 4). The metal profiles are grasped and held by revolving gripping members (7). At least during the foaming or setting process, the gap between the metal profiles is sealed off by a sealing strip (10, 11, 14) of flexible material. <IMAGE>

Description

(34) CONTINUOUS PRODUCTION OF COMPOSItE SECTIONS (71) We, SwIss ALUMINIUM LTD., a company organised under the laws of Switzerland, of Chippis (Canton of Valais), Switzerland, do hereby declare the invention, for which we pray that a patent may be granted to lus and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention concerns the continuous production of composite sections, of the type including at least two metal sections sandwiching a core of plastics material, such as polyurethane foam, the composite sections being produced by holding the metal section between facing conveyors after the plastics material has been introduced there- between and whilst it solidifies.

There are already on 'the market doubletrack conveyor systems, between the facing, synchronously moving belts of which the metal sections are transported in facing, groove-shaped recesses. Both of the belts lie directly against the metal sections in order to cover the spaces 'therebetween and counteract the pressure developed by the setting plastics material. Since the metal sections are held in place by the moving pair of belts, only very limited shapes of metal section profile can be handled. The free surfaces of the plastics core between the metal sections usually stick to the moving belts and are therefore rough in appearance having a coarse pored structure.

According to the present invention, however, apparatus for use in the continuous production of composite sections, of the type including at least two metal sections sandwiching a core of a plastics material, comprises a pair of facing conveyors, at least one of which is movable and carries a series of exchangeable locating elements having recesses which are for temporarily engaging at least two metal sections and holding them in predetermined positions whilst a plastics material solidifies therebetween.

The present invention extends to a process incorporating use of the apparatus defined above.

Preferably, each of the conveyors is movable and carries a respective series of said exchangeable locating elements, each of which is associated with a respective sealing element which is guided into 'the recesses in the locating elements to isolate them from the plastics injected therebetween in use. The individual locating elements engage the continuously moving metal sections and hold them apart at the desired distance. The sealing elements close off the spaces between the metal sections thus preventing the platics core from being baked on to the locating element. The sealing elements thus enable the exposed surfaces of the final plastics core to be substantially pore-free.

Thanks to this measure of providing exchangeable locating elements on at least one of the conveyors, which may for example be in the form of endless chains, any shape of metal section can be accommodated, the locating elements being exchanged for ones of different cross-section as necessary.

'Preferably, the sealing elements are in the form of endless belts which run round with the endless chains, one or both of the endless belts including an associated supporting strip, preferably made of spring steel. The metal support strips prevent the sealing belts from tearing, with the result that the sealing belts are not limited by the strength of the material from which they are made.

lIt has been found to be particulariy favourable to make the locating elements themselves rigid so that the metal sections can be clamped into them and held a predetermined distance apart thus forming, with the lower sealing belt, a groove into which the plastics material can be introduced before the outer sealing belt doses the open face of said groove. The locating ele ments are in fact preferably formed as light metal blocks, the recesses in the blocks belonging to one conveyor being all substantially the same, but being different from as well as being preferably displaced to one side with respect to the blocks of the other conveyor. This permits projecting parts of the metal sections to be supported at their sides by the blocks.

Chain link belts, which may be driven by chain drums, are usefully employed as the means of conveyance. Away from the so-called pressure or hardening zone, in which the sealing belts are in contact with the composite section being produced, the sealing belts are raised from the profiled blocks by deflection rollers. This permits better regulation of the sealing belt tension and also allows the recesses in the blocks to be cleaned if necessary. Furthermore, the sealing belts, which may for example be made of a resiliently deformable material such as chloroprene rubber, are able to compensate for small tolerances in the dimensions of the metal sections.

The preferred apparatus which is used to carry out 'thins process includes, as a part -thereof, a commercially available foaming machine with thermal treatment facility.

Raw material is fed to a mixer, after which it is passed on to a container in order to prevent sedimentation of any filler material which may be present in the mixture. In order to improve efficiency, a plurality of mixers can be connected to one foaming machine, and there can be simultaneous production of a number of composite sections.

As has already been indicated, by changing the light metal blocks a variety of composite sections can be produced by a single apparatus. The blocks are designed for the section in question; the height and width of the blocks can be varied, but the distances between the blocks must be sufficient to permit their travel around the preferred chain drums.

As an experiment, and counter to the original intensions, the lower chain belt was replaced by a fixed conveyor formed as a track of rollers, in order to be able to employ cassettes which were available from other known processes. These cassettes were, in use, covered by the upper series of blocks and their associated sealing belt. This alteration, which is within the scope of the invention, gave good results and also simplified the process of producing composite sections which have undercut recesses.

further advantages, features and details of the invention are revealed by way of the following description of apparatus embodying the invention, and by way of the accompanying drawings, viz:- 'Figure 1 is a schematic side view of the apparatus; figure 2 is an enlarged cross-section taken along the line II-II of Figure 1; Figure 3 is plan view of the detail shown in Figure 2; Figure 4 is an enlarged cross-section taken along the line IV-IV of Figure 1; and, Figure 5 is similar to Figure 4 but shows a composite section being produced at the position shown in Figure 2.

Apparatus R is fitted with an endless con veyor chain ,belt 3 which runs round two chain drums 2 mounted on a frame 1. A second chain belt 4 similarly runs over chain drums 5. A motor drive 6, which has for example a working capacity of 2 HP, pro vides synchronous movement for both belts 3, 4. As can be seen particulariy well in Figures 2 and 3, profiled light metal blocks 7u and 71, constituting locating elements, are provided on both of the chain belts 3, 4 and are spaced apart at a distance "b" from each other in a direction parallel to the movement of the chain belts.

The blocks 71 of the lower chain belt 3 are secured in place by screws 8 and have the same shape because they come from the same extrusion, whilst the facing blocks 7u of the upper chain belt 4 are similarly secured but have a shape which is different from that of the blocks 71. Thanks to the fact that the profiled blocks can be ex changed for other ones, the contours of the overall space 9 defined by the blocks, shown to be of height "h", can readily be changed. Preferably, however, each of the upper and lower blocks is asymmetric in cross-section, the upper blocks being dis placed laterally with respect to the lower blocks as shown in Figure 3, which also shows that the length of each block is far greater than its height or width.

A spring steel strip 10 supporting a belt 11 of chloroprene rubber fits into recesses in the profiled blocks 71 of the lower chain belt 3. Both the strip 10 and the belt 11, constituting a sealing element, run round with the chain belt but at a distance from it. This distance is determined at the upper part 3u of the cycle by the height "c" of the profiled blocks 71, and at the lower part 31 of the same belt 3 by deflection rollers 12. Corresponding deflection rollers 13 guide an endless sealing belt 14 around the upper chain belt 4, the belt 14 coming in contact with recesses in the profiled bloks 7u during the lower part of its cycle.

In order to control the tension in the belts 10 and 14, and to ensure that they are intro duced accurately into the profiled blocks, respective rollers 12e and 13e are mounted on pivotable arms 15 near entry end K of the apparatus. Figure 4 shows two alumin blocks 71 of the lower chain belt 3, having ium sections P1, P2 lying in the profiled been fed into the apparatus R along a runin table 20 via rolls 21 in plane E.

Both sctions P1, P2 are laterally suported by rolls 23. A channel between the metal sections, which is open at the top and closed at the bottom by the chloroprene rubber belt 11, is filled with polyurethane foam S in a foaming zone Z. The metal sections pass through the foaming zone Z on the lower chain belt 3, the the upper chain 4 does not engage the sections until the end of this zone Z. This arrangement allows a supply pipe 24 of a mixer 25 connected to a foaming machine 26 to have access to said channel. Figure 1 also shows rolls 27 near the mixer for pressing the metal sections into the profiled blocks 71.

After the foaming operation the sealing belt 14, which runs along with the upper chain belt 4, comes down on to the metal sections and covers a horizontal gap 28 (length nl in cross-section) which remains between those sections. In a similar manner, a gap 29 at the bottom of the metal sections (length n2 in cross-section) is closed off by the chloroprene rubber belt 11 along the whole length of the sectons as they are conveyed through the apparatus R.

The resultant composite section passes along in the direction X, through a curing or solidifying zone Y, in an interval of three to twelve minutes and leaves the apparatus via a run-out table 30 which is provided with rollers 31.

It will be appreciated. that both of the moving conveyors described above need not necessarily be in the form of endless chains, nor need both series of the locating elements be associated with respective sealing elements, nor need both of the sealing elements be in the form of endless belts. It is believed, however, the use of the preferred embodiment eliminates the disadvantages of the prior art at the same time as achieving a high level of output of composite sections of good quality. The apparatus R is thus capable of use in the continuous production of composite sections having a plastics core sandwiched between two or more metal sections, the number of metal sections permitted clearly being dependent upon the shapes of the recesses in the locating elements.

WHAT WE CLAIM IS. 1. Apparatus for use in the continuous production of composite sections, of the type including at least two metal sections sandwiching a core of a plastics material, comprising a pair of facing conveyors, at least one of which is moveable and carries a series of exchangeable locating elements having recesses which are for temporarily engaging at least two metal sections and holding them in predetermined positions whilst a plastics material solidifies therebetween.

2. Apparatus according to claim 1, in which each of the conveyors is movable and carries a respective series of said exchangeable locating elements.

3. Apparatus according to claim 1, in which only one of the conveyors is moveable and carries a series of said exchangeable locating elements, the other conveyor not being movable but including means, such as rollers, for transporting a succession of individual cassettes.

4. Apparatus according to any preceding claim, in which the, or at least one of the, conveyors carrying the locating elements is in the form of an endless chain.

5. Apparatus according to any preceding claim, in which the, or at least one of the, series of locating elements is associated with a sealing element for isolating those locating elements, in use, from the solidifying plastics material.

6. Apparatus according to claim 5, in which the, or at least one of the, sealing elements is in the eform of an endless belt.

7. Apparatus according to claim 6, in which the, or at least one of the, endless belts is formed of a resiliently deformable material, such as chloroprene rubber.

8. Apparatus according to claim 6 or claim 7, in which the, or at least one of the, endless belts is supported by an endless strip of a more rigid material, such as spring steel.

9. Apparatus according to any one of claims 6 to 8, in which the, or at least one of the, endless belts is separated from its associated series of locating elements for a part of its cycle of movement.

10. Apparatus according to claim 9, in which the, or at least one of the, endless belts which is so separated is deflected by a pivotally-mounted roller.

11. Apparatus accordng to any one of claims 5 to 10, in which the, o'r a given one of the, sealing elements co-operates with its adjacent locating elements to define a channel which is open along one face for the introduction of plastics material to be solidified.

12. Apparatus according to claim 2 and claim 11. in which the open face of the channel is subsequently closed by a sealing element associated with other series of locating elements.

13. Apparatus according to any preceding claim, in which the locating elements take the form of light metal blocks.

14. Apparatus according to claim 2 and claim 3, in which the blocks are asymmetric in cross-section, the blocks carried by one conveyor being displaced laterally with respect to the blocks carried by the other conveyor.

15. Apparatus according to claim 13 or claim 14, in which the length of each block, parallel to the direction in which its associ

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. been fed into the apparatus R along a runin table 20 via rolls 21 in plane E. Both sctions P1, P2 are laterally suported by rolls 23. A channel between the metal sections, which is open at the top and closed at the bottom by the chloroprene rubber belt 11, is filled with polyurethane foam S in a foaming zone Z. The metal sections pass through the foaming zone Z on the lower chain belt 3, the the upper chain 4 does not engage the sections until the end of this zone Z. This arrangement allows a supply pipe 24 of a mixer 25 connected to a foaming machine 26 to have access to said channel. Figure 1 also shows rolls 27 near the mixer for pressing the metal sections into the profiled blocks 71. After the foaming operation the sealing belt 14, which runs along with the upper chain belt 4, comes down on to the metal sections and covers a horizontal gap 28 (length nl in cross-section) which remains between those sections. In a similar manner, a gap 29 at the bottom of the metal sections (length n2 in cross-section) is closed off by the chloroprene rubber belt 11 along the whole length of the sectons as they are conveyed through the apparatus R. The resultant composite section passes along in the direction X, through a curing or solidifying zone Y, in an interval of three to twelve minutes and leaves the apparatus via a run-out table 30 which is provided with rollers 31. It will be appreciated. that both of the moving conveyors described above need not necessarily be in the form of endless chains, nor need both series of the locating elements be associated with respective sealing elements, nor need both of the sealing elements be in the form of endless belts. It is believed, however, the use of the preferred embodiment eliminates the disadvantages of the prior art at the same time as achieving a high level of output of composite sections of good quality. The apparatus R is thus capable of use in the continuous production of composite sections having a plastics core sandwiched between two or more metal sections, the number of metal sections permitted clearly being dependent upon the shapes of the recesses in the locating elements. WHAT WE CLAIM IS.

1. Apparatus for use in the continuous production of composite sections, of the type including at least two metal sections sandwiching a core of a plastics material, comprising a pair of facing conveyors, at least one of which is moveable and carries a series of exchangeable locating elements having recesses which are for temporarily engaging at least two metal sections and holding them in predetermined positions whilst a plastics material solidifies therebetween.

ated conveyor is to move, is far greater than its height and width

16. Apparatus according to claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.

17. A process for the continuous production of composite sections, of the type including at least two metal sections sandwiching a core of a plastics material, in which at least two metal sections are temporarily engaged by at least one moving series of exchangeable locating elements carried by a respective one of a pair of facing conveyors, recesses in the locating elements acting to hold the metal sections in predetermined positions whilst plastics material solidifies therebetween to form a core.

18. A process according to claim 17, in which each of the conveyors is movable and carries a respective series of said exchangeable locating elements, each of which is associated with a respective sealing element which acts to isolate those locating elements from the solidifying plastics material tO allow the exposed surfaces of the final plastics core to be substantially pore free.

19. A process according to claim 17 or claim 18, in which the plastics material is introduced as polyurethane foam.

20. A process according tto claim 17 and substantially as hereinbefore described with reference to the acoompanying drawings.