GB2251468A - Flange connection for rectangular ducts - Google Patents

Abstract

In the connection of rectangular air conditioning ducts use is made of prefabricated flange connections. These consist of a frame comprising four corner angles and four frame legs. The frame must hold together until it is pushed onto the end of the duct and fastened there by spot welding. Hitherto centre punch presses or other presses have been used for joining corner angles and frame legs. The invention makes it possible to secure the corner angles to the frame legs by means of a percussion tool. For this purpose a bead is bent into the frame legs, the walls 33, 34 of which bead are guided in a longitudinal slot 92 between the leg halves 94, 97 of the corner angle. By their front region 123, 124 they pass into a deformation space 122, in which they are deformed so that corner angle and frame leg can no longer become separated from one another. <IMAGE>

Description

22514,53 1 FLANGE CONNECTION FOR DUCTS The invention relates to a flange

connection according to the preamble of the main claim. A flange connection of this kind is known f rom German Patent Specification 25 01 611. It survived only a short time on the market although marketed by a powerful supplier. In practice it was found that, at least for the larger sizes, one radial web had to be bent down relative to the longitudinal web in order to be able to obtain the necessary sealing prestress. However, as soon as prestressing is effected, loadability is reduced by the amount of the prestress. In addition, the bead had to have the cross-sectional shape of a press fastener and could not project to a height greater than the thickness of the corner angle. This requires difficult bending work. Finally, the bead had to be pressed in the legs in a determined position in a recess. This requires a special machine for the operation. Without such a machine the pressing action will not be applied to the recess of the slots, but to the metal of the corner angle, which entails various disadvantages.

The trade went over completely to solutions in pressing 2 accordance with German Utility Model 74 01 814. For this -purpose, however, additional machines are required in the form of centre punch presses. The impressing of the dimples may damage the zinc coating.

When the corner angles are inserted it cannot be seen from the outside where the holes are situated in the legs. The legs are weakened by the holes. In the event of incorrect assembly, although the indentations can be drilled out, the frame legs are nevertheless shortened by at least 4 centimetres if it is desired to reuse them, which means that they cannot then be used for the intended purpose.

The object of the invention is to make the corner angles undetachable from the frame legs, without the aid of additional machines but solely by means of a hammer. At the same time, basic rethinking of this technology should not be reqiired. Even unskilled labour must be able to make the connection in the manner prescribed by the designer. 20 According to the invention this obiect achieved by the features shown in the characterising part of the main claim. Apart from the finished connection, the invention also relates to the component parts, insofar as the frame legs and corner angles are concerned.

The invention is explained with the aid of preferred examples of embodiment. In the drawing:

Figure 1 is a view in perspective of a frame leg in a first example of embodiment, on a scale of 2: 1; Figure 2 is a similar view to Figure 1 in the case of a second example of embodiment; Figure 3 is a cross-section corresponding to Figure 1, with legs inserted into a cavity; Figure 4 is the plan view of a corner angle on a scale of 1: 1; Figure 5 is a section along the line 5 - 5 in Figure 4; Figure 6 is a broken-away view similar to Figure 4, but with only a single leg; Figure 7 is a view in the direction of the arrow 7 in Figure 6; Figure 8 is a view on a substantially enlarged scale of the deformation space, with -bead walls deformed; Figure 9 is a similar view to Figure 8, but with a different deformation space; Figure 10 is a section showing a third form of bead; Figure 11 is a systematic representation of forces, the legs being not yet completely inserted.

According to Figure 1, a frame leg 12 comprises an inner radial web 13, an outer radial web 14, an outside web 16, an inner longitudinal web 17 and an outer longitudinal web 18. A duct wall 19 can be inserted into the wall gap 21, its end face 22 lying either entirely to the lef t on the radial web 13 or else, in the case of broad legs as shown in Figure 3, on said legs. In the known technique, af ter a frame composed of corner angles and frame legs has been pushed on, the duct wall 19 is welded to 17 and 18 by spot welds 25, so that this region is rigid for the present purposes.

The radial web 13 is plane in the downward direction. The next flange connection would lie there against if an adjoining length of ducting were laid.

In the final assembled state the radial web 13 is thus on the inner side.

The outside web 16 merges in the form of a U-bend 23 into the radial web 14 in the manner illustrated.

Approximately in the middle of the radial web 14 a bead 24 is formed. First bends 26, 27, spaced apart and disposed at an angle of about 900 in the outward direction can be seen. These merge via short wall strips 28, 29 into two second bends 31, 32, followed by bead walls 33, 34 which lie opposite one another and which are spaced apart from the wall strips 28, 29 and are at right angles to the radial web 13, which in turn is at right angles to the geometrical centre axis of the duct. The bead walls 33, 34 merge into a third bend 36, which is located at a minimum distance 37 from the inner face of the radial web 13. In another example of embodiment, which is not illustrated, the distance 37 may also be zero. The radial webs 13, 14 are plane. A first cavity half 38 is bounded by 34, 13, 16 and 14, while 33, 14, the bottom part of 17 and 13 bound a second cavity half 39. The sheet metal material used has a thickness of 0.7 millimetre and thus, although having the same rigidity, is f rom one to two tenths of a millimetre thinner than was hitherto the case with frame legs of the same capability. Even small savings of material amount to a great deal in the case of the frame legs 12, since the latter are mass produced goods.

In the example of embodiment shown in Figure 2 the bead 41 is bent out of the inner radial web 42, also approximately at its centre. Spaced apart, there are here 920 bends 43, 44 which merge into bead walls 46, 47 extending at right angles to 42. The distance between their inside faces can be seen from the 2:1 drawing, just as dimensions can be seen from Figure 1. The bead walls 46, 47 merge into a U-bend 48. As can be seen, the bead wall 46, 47 extends beyond the plane of the outer radial web 49 and is inserted, with lateral clearance, correspondingly in a U-channel 51 ---5 which is bent in the outward direction from the outer radial web 49. In the example of embodiment the U-bend 48 is in contact with the bottom 52 of the U-channel 51, on the inner side of the latter, but is at a distance from the inner faces of the side walls 53, 54. In another example of embodiment, which is not illustrated, the distance between 48 and 52 may also be zero. Two cavity halves 56, 57 are once again formed. The outer radial web 49 does not extend so far towards the inner longitudinal web 58 as in the first example of embodiment. On the contrary, an inclined surface 59 extends from it to the outer longitudinal web 61, which is therefore shorter but still has room for spot welds. Corresponding to the U-bend 23, here again there is a U-bend 62, which however is not so directly bent back over itself but has a broader profile.

According to Figures 4 and 5, a corner angle 63 punched and stamped from 3 millimetre steel has a middle plate 64. The latter has two centring holes 66, 67 symmetrical to the angle bisector 68, and a fastening hole 69 with the centre in the angle bisector. The middle plate 64 is stamped out in the downward direction, as shown in Figure 5, in accordance with a boundary line 71, to an extent corresponding to the thickness of a radial web. Legs 72,73 adjoining the middle plate remain in the original plane, together with a bridging region 74, so that the end face 76 of the duct wall 19 can lie continuously flat as shown by the line 77. At the inner end of the legs 72, 73 stop corners 78, 79, 81, 82 are provided, against which the end face of the outside web 16 and that of the inner longitudinal web 17 strikes when the corner angles 63 are driven in completely.

The outside faces 83, 84, 86, 87 of the legs 72, 73 extend parallel to the geometrical angle bisector 68 and are at the same time the outside surfaces of a strip material of the width 88, so that wastage in the manufacture of the corner angle 63 is minimised. The strip material 89 is indicated. A longitudinal slot 91, 92 extending at 450 to 86 is provided in the middle of each of the legs 72, 73. Because of the cut indicated at 83, 84, 86, 87, shorter leg halves 93, 94 and longer leg halves 96, 97 are formed. One-third circle roundings 98 of the same radius ensure easier insertion. The longitudinal slots 91, 92 are punched at right angles to the planc of the drawing in Figure 4 and have walls extending accordingly. The inner region of the longitudinal slot 92 will be described with reference to Figure 8. The longitudinal slot 91 has a corresponding form.

8 - Right from the outside and as far as constrictions 112, 113, as shown in Figure 8, the bead walls 33, 34 bear with pressure against inner faces 99, 111 of the longitudinal slot 92. Said constric tions have slide-on flanks 114, 116 which extend gently inwards and, after a point 117, 118 of maximum narrowness turn outwards again at their flanks 119, 121, which are already part of a deformation space 122. The deformatLon space 122 is circular in this view and, like the surfaces previously mentioned, lies symmetrically to a geometrical centre plane 123 extending at right angles to the plane of the drawing in Figure 8. The deformation space 122 has exactly the same width as the longitudinal slot 92 and forms the direction extension of said longitudinal slot 92, interrupted only by the constrictions 112, 113. Hammer blows f rom the lef t on the lef t-hand end f ace of the middle plate 84 have deformed the end region of the bead walls 33, 34 into the deformation space, said bead walls assuming random positions. The bead wall 33 at the top in Figure 8 has been def ormed by an outwardly directed bend 123 over a region of a length of about 3 mm, which is thus rigid in relation to the thickness of the bead walls. In the region 124 the bead wall 34 has cut slightly into the edge of the deformation space 122 and is also bent out at 124, although in the upward direction. The extent to which these bead walls are deformed into the deformation space 122 is determined by the stop corners 81, 82, the line 126 connecting which is shown in Figure 8. In this preferred example of embodiment the middle plate 64 lies in the same plane as the leg 73 (or also 72), which provides the advantage that the leg 73 is better joined to the middle plate 64 without the weakening boundary line 71. If the frame leg 12 strikes against the stop corners 82, 81, an assurance will be given that sufficient deformation work has been done in the deformation space 122 without this being seen from the outside. The 9 o'clock point 127 of the deformation space 122 is therefore a slight distance from the connecting line 126. This distance indicates how far in the interior the deformation has been effected.

However, it is also possible to provide only a single constriction 112.

As shown in Figure 9, the constriction may also be entirely dispensed with. The deformation space will then comprise two branches 128, 129 which open out at angles of about 450 from the centre plane 125, so that between them a plough 131 is formed which spreads the bead walls 33, 34 apart in that region.

The preferred examples of embodiment have in common the feature that 33 and 34 lie against 99, 111 under pressure, it is true, but without permanent deformation, or at least without substantial permanent deformation, and that the permanent deformation is brought about only by the constrictions 112, 113 or the like, just as in the deformation space 122.

As shown in Figure 6, with constrictions identical in this respect there is a slight clamping of 33, 34 (as is also the case in the example of embodiment illustrated in Figure 8). Here, however, the deformation space 131 has the shape of a bottle open on the right, with a bottle bottom 132 at right angles to 125. It is therefore not necessary for the deformation space to be circular. Here again the bottle bottom 132 ends at a sufficient distance before the connecting line 126. The leg merges as a plane surface into the middle plate. On the other hand, the outside edge 133, 134 is also bent away over the outside corner 134 towards the rear in Figure 6 and downwards in Figure 7, to form a bend 13 6, bending being effected to an extent corresponding to the thickness of the sheet metal of the frame legs. A support surface 137 of sufficient area in the direction of the next neighbouring corner angle is thus obtained.

According to Figure 10 a bead 138 having an eyelet-shaped cross-section is bent over inwards. In the tubular region of the bead 138 the walls, which now extend over a circular path, are nevertheless still spaced apart, while the elbows 139, 141 of the eyelet are in contact with one another. Because the elbows are closed, it is not possible for a connection strip extending over the length of the frame leg to be inserted into this bead 138, towards the next frame leg. According to Figure 2, however, with this construction, since it is open towards the next frame leg, a connecting strip 142 of a maximum thickness of 1.6 mm could be inserted, this strip then extending into the complementary opening of the neighbouring bead, so that in the case of particularly long frame legs it is possible to achieve alignment and possibly also additional sealing.

For the sake of simplicity the deformation space has been omitted and the bead is also not shown as double-walled. Since the bead is oversized in relation to the longitudinal slot, the leg is supported at the top on the outside web 16 and at the bottom on the longitudinal web 17, so that from the point of view of stiffness the longitudinal slot does not entail any weakening. The arrows 143 are symbolic force arrows. The same would also be true if the lower leg were not supported directly on 17, but on a duct wall 19 advanced as far as the inner radial web.

- 12 The corner angle need not be flat and plane, but may also have a concave curvature. If desired, the radial web 14 may also be deformed from outside into the deformation spaces, in the traditional manner.

Claims (35)

- 13 CLAIMS:

1. Flange connection for rectangular four-walled air conditioning ducts, comprising a steel corner angle from whose middle plate two legs extend, each of which contains a longitudinal slot at right angles to the plane of the leg; also comprising frame legs which comprise a radial web, an outside web, a longitudinal web and a bead, the bead being bent out of the radial web and consisting of at least three bends; and wherein each leg extends substantially parallel to the radial web and lies against the latter by at least part of its surface, and its slot receives the bead in the overlap region; and further comprising a region of permanent deformation between bead and slot, characterised by the following features:

a) The frame legs have two radial webs, namely an inner and an outer web, which in substantial regions are parallel to one another and which are joined together by the outside web.

b) The frame legs have two longitudinal webs, nanmely an inner and an outer web, which receive the walls between them.

c) Between the outside web, the two radial webs and the inner longitudinal web a cavity is located into which the bead is bent.

d) The legs can be inserted into the cavity until they encounter a stop.

e) In the inner end region of each longitudinal slot a constriction is provided, the inside width of which is smaller than the outside dimension of the bead.

f) Behind the constriction a deformation space is provided, in which the outermost edge regions of the bead remain and, without play, are deformed to a shape whose transverse dimension is larger than the inside width of the constriction.

g) The bead walls lying opposite one another are spaced apart by a distance permitting the deformation according to b).

2. Flange connection according to Claim 1, characterised in that the constriction starts from both walls of the longitudinal slot.

3. Flange connection according to Claim 1, characterised in that the constriction is symmetrical to the centre of the longitudinal slot.

4. Flange connection according to Claim 1, chazac-Lt=-Libe-d in -cn-arr-ne constriction, viewed from its inlet, has at least one constant slide-on flank.

5. Flange connection according to Claim 1, charac- - 15 terised in that the inside width amounts to 2/3 20% of the distance between the walls.

6. Flange connection according to Claim 1, characterised in that the inside width is 2 mm, the distance between the walls 3 mm, and the thickness of the sheet metal of the frame leg 1 mm.

7. Flange connection according to Claim characterised in that the deformation space approximately as wide as the longitudinal slot.

8. Flange connection according to Claim 1 or characterised in that the deformation space approximately pear-shaped.

1 ' is

9. Flange connection according to Claim 8, characterised in that the deformation space is 15 circular at least over the inner 1800.

10. Flange connection according to Claim 1, characterised in that the nearest region of the deformation space to the line connecting two stop corners is at a distance from said connecting line.

Flange connection according to Claim 10, - 16 characterised in that the distance is at least 1 mm.

12. Flange connection according to Claim 11, characterised in that the distance is in the range of 1-4 mm.

13. Flange connection according to Claim 10, characterised in that the distance amounts to at least one sheet metal thickness.

14. Flange connection according to Claim 1, characterised in that the deformation space is a V shaped end branching of the longitudinal slot, the branches forming between them the shape of a plough tip.

15. Flange connection according to Claim 14, characterised in that the branches of the end branching are narrower than the longitudinal slot.

16. Flange connection according to Claim 1, characterised in that the ends of the legs are cut off approximately parallel to the angle bisector of the corner angle.

17. Flange connection according to Claim 1, characterised in that the middle plate merges as a plane surface into the legs.

17

18. Flange connection according to Claim 1, characterised in that in the outside corner region the middle plate has a narrow web bent out of its plane.

19. Flange connection according to Claim 18, characterised in that the web is extended at the outside edges of the middle plate as far as the connection of the legs.

20. Flange connection according to Claim 1, characterised in that no holes are provided in the legs, at least in the region of the constriction.

21. Flange connection according to Claim 1, characterised in that the two legs have the same width.

22. Flange connection according to Claim 1, charac- is terised in that the bead is bent out of the outer radial web.

23. Flange connection according to Claim 22, characterised in that two first bends, spaced apart, are provided in the outward direction from the outer radial web, that these are followed by two second bends which guide the bead into the cavity, forming 18 the walls past the first bends, and that before reaching the inner radial web the bead has a third bend in the form of a U-turn.

24. Flange connection according to Claim 23, characterised in that the first bends merge via short wall strips into the second bends.

25. Flange connection according to Claim 23, characterised in that a space is left between the wall strips and the walls.

26. Flange connection according to Claim 23, characterised in that the first bends amount to about 900 and the second bends and the third bend to about 1801.

27. Flange connection according to one or more of the preceding Claims 23 to 26, characterised in that all the bends are as round as possible.

28. Flange connection according to Claim 1, characterised in that the bead is bent out of the inner radial web.

29. Flange connection according to Claim 28, 1 - 19 characterised in that two fourth bends, spaced apart from one another, are provided in the inward direction f rom the -inner radial web, said bends guiding the bead into the cavity, and that in the region of the outer radial web the bead has a fifth bend in the form of a U-turn.

30. Flange connection according to Claim 29, characterised in that the fifth bend engages in an outwardly stamped channel in the outer radial web.

with the side

31. Flange connection according to Claim 30, characterised in that the fifth bend is not in contact walls of the channel, but is supported against the side walls in the case of excessive lateral deflections.

32. Frame leg according to one or more of the preceding claims.

33. Corner anqle accordincr to one or ntux-e of the preceding claims.

34. A kit for forming a flange connection for rectangular, four-walled ductings, said kit comprising four frame legs for forming a flange and four corner 1 - 20 pieces for holding the frame legs in position relative to each other, each frame leg having a bead which has two substantially parallel spaced walls and each corner piece comprising two slots extending at right angles to each other for receiving the beads of two frame legs disposed at right angles to each other, each slot being configured to deform at least one wall of the bead received therein to secure the frame leg provided with the bead to the corner piece.

35. Any of the flange connections, substantially as hereinbefore described with reference to the accompanying drawings.