Manufacture of pipes or tubes

The invention relates to a method for the production of tubes which are helically wound at least partially and parallel to the longitudinal edge vorgerillten strip of thin sheet or foil and in which the fold by nesting, collapsing and subsequent folding pressing of opposite Randabwicklungen the pipe wound strip is formed, the fold lies in the flank of a groove. Furthermore, the invention relates to a workpiece for use in such a method and a tube produced by this method.

Such tubes are known in which the fold, which connects the entire longitudinal edges of the sheet or foil strip wound to the tube, lies in a parallel plane to the lateral surface of the tube. The scoring of the tube is thus interrupted in the known tubes in the region of the folds. Since the folds must have a certain width and the strips from which the tubes are wound are in many cases relatively narrow, this results in a rather unfavorable relationship between the surface of the tube which is provided with grooves and the surface of the tube, in animal the folds lie; this has significant adverse effects on various properties of such tubes. The tubes are therefore substantially grooved to provide flexibility similar to tubing and to be able to provide relatively tight bends with little radius during installation. Furthermore, such tubes are due to their spiral ROiung extendable or compressible, so that it is not necessary, for example, for laying, cut to exact dimensions.

In the known folded, grooved pipes has also been found to be disadvantageous that at a too tight bend, but especially in multiple stress on train, the fold tears during repeated stretching of the fold, so that a typical damage, the tearing arises as a flycatcher ways the smooth in the axial direction folds such known pipes can not very strongly compress in the axial direction. Of course, the apex pressure strengthening in the region of the folds is considerably lower than in the region of the grooves.

It is a method for producing pipes of the generic type known (US-PS 39 82 414) after which a tube is to produce, in which the fold lies in the edge of a groove In the danao-i produced tube, the grooves are relatively sharp and her legs have an angle of about 45 ° to each other. In particular, the fold is designed such that it overlaps the entire flank of a groove from one vertex to the other vertex Such a formation of the fold is made in the method according to this prior art in the final position in the pipe, ie in an inclined position. The pre-grooved strips are bent at right angles at their two longitudinal edges between profiled rollers acting against each other. Such an operation is not feasible in practice, because the distance between the right-angled bends is dictated by the intermeshing rollers. Differences in plate thickness, even if they are as small as can never be avoided in practice - even minor Cause impurities, dal) the two gcgeneinandcrwirkcnden form rollers with their radially parallel flanks stuck together and u. U. also tear the sheet. Deformation of sheet metal strips according to this prior art is therefore unfeasible in practice.

Furthermore, according to this prior art, preformed between rolls of sheet metal strip is then pulled through a molded mouthpiece in which the angled at right angles longitudinal edges are bent beyond the right angle to an acute angle. This will reduce the manufacturing

SH -is

speed severely limited, furthermore, special demands are placed on the material as well as on the tool and the workpiece, for example, a lubricant is required, which proves to be disadvantageous in the subsequent use of the tubes produced by pulling the pre-grooved strip through a fixed mouthpiece For further deformation also very high demands are placed on the accuracy of the bandwidth of the material and its rolling properties. If such requirements were not met, the edges would flare at the respective counterpart of the mouthpiece or the printing plate. Again, the band consisting of sheet metal must have no differences in the sheet thickness.

In the further implementation of the known method, the metal strips are wound on a winding mandrel, folded together at their edges, it should be noted that the two interlocking flanks of the metal strip must have a distance from each other, which corresponds to their angular position beyond the right angle because they go otherwise do not put together when winding up. Subsequently, the thus wound tube is to be provided at the nested, angled edges with a fold and although the fold should be formed in an inclined position so folded back in an inclined position so that it comes to rest in the flank of a groove. Further details of this particularly critical phase of seam formation are not given in the cited prior art.

From another prior publication to the prior art (US-PS 36 06 779) is known as a method for moving a folded at the edges of a wound on a winding mandrel metal strip is simply nesting fold to perform first the radially projecting fold between two counteracting Rollers, one of which is provided with a ridge and tilted and then pressed by another roller in the plane, is printed on the outer surface of the winding core. Bs is then merely taught to produce a fold which is folded in parallel to the tube and thus remains. It should be noted, however, that this is not a tube which is fully flexible and compressible

The invention has the object to avoid the above-described disadvantages of known tubes and to provide a helically wound at least partially vorgerillten strip tube b i i the longitudinal edges of the strips are folded, in which a continuous uniform creasing of the lateral surface is present and in which by the Falzausbildung a juxtaposition of the rib flanks is made possible According to the invention may be one-or multi-layer pipe.

To solve the problem, a method of the generic type is characterized in that the pre-grooved strip on one longitudinal edge following an ungerillten sheet metal section with distance from the next groove with a rib whose outer leg forms the edge and at the other longitudinal edge with an angling in the same direction as the rib is provided and then wound in such a way to the pipe, that the bend engages in the rib then this compound to the side of the bend under compression to fold in a plane parallel to the lateral surface of the tube (in the main plane) folded and then at the location of this fold another rib is formed, which fold in one of its flanks, wherein the width of the fold is less than the radial width of a groove flank, so that one of the folding edges are at least at a distance of the seam thickness from the vertexes of the grooves. According to a development of the invention, after winding the first pipe layer, a second layer of pipe in the same manner wound on it at the

Falο fold is offset by at least the width of an unfolded groove and then forming grooves or ribs at the location of the folds under formation of the folds in one of the flanks of the formed grooves.

A workpiece for use in the above method is characterized in that the strips of sheet or foil on one or both sides are provided with a support of any material. One or more pads may also be wound on it after the first wound strip has been folded.

A tube made in accordance with the method of the present invention is characterized in that it is compressed to such an extent that the flanks of all the grooves contact one another wholly or partly.

In deai method according to the invention, the seam is formed along the entire longitudinal edge of the pipe wound strip in a special way it thus arises compared to the methods known in the prior art, an additional workload. The advantages achieved are that in addition to the purely optical, altered appearance of the tube, which shows a uniform continuous grooving is achieved that such a tube optimally squeeze and pull apart leaves all grooves, including those grooves in the Faiz is absorbed equally and in the same way. It is therefore also possible to compress such tubes much more often and pull apart without thereby the fold is overstressed.

After the invention, it depends. the PaI / to put in a Riil flank and that in a Faizbreite, which is less than the radial width of a Rillsnflanke.

By this arrangement of the fold results in the considerable advantage that this fold on the one hand forms a double undercut and is no longer subjected to train, on the other hand results from the fact that the fold extends approximately in the radial direction a substantial improvement in the Vertex compressive strength of the entire tube , especially in the area of ​​the fold. A tube according to the invention can be laid in much narrower bending radii than was previously the case with folded tube, it can be used for the production of such tubes and thinner sheets and / or foils, because the stress in the region of the fold is substantially lower or completely disappears. Heretofore, it has been preferred to use thin aluminum foils or sheets for the production of such pipes because the use of other metals has often been associated with certain difficulties in forming and forming the pipe. By the method according to the invention, such difficulties are overcome, so that for pipes according to the invention, films of other metal, in particular stainless steel are used.

The fact that the fold is arranged radially and the tube is grooved continuously, can be such

Squeeze pipes much closer than was previously the case, and to the extent that the edges of the grooves touch each other. Nevertheless, let such a tube again pull apart very far, even so far outstretched that the grooves are almost formed to s light roof shape and the tube is almost smooth surface. This process can be repeated several times without cracks occur. When stretching the tube of the fold is no longer claimed to train because he lies in the edge of a groove. The flexibility of the pipe is significantly improved

In a tube according to the prior art mentioned in the first place, a close juxtaposition of all rib flanks can not be achieved, because due to the fold formation shown there (Breiie of the fold) ts and other also a spring back of the flanks is effected from each other. The compressibility of the grooves is not möelich there.

Line of the main effects and thus a significant advantage of the method according to the application can not be achieved with the state of the art mentioned in the first place, namely in the finished tube deformation of those ribs in the fold is a flank, in almost the same Way, as with the ribs whose flanks have no folds. However, just this effect is extremely important in the invention. It is thus achieved that the groove tubes thus produced are compressible to one-third to one-fifth of their working length and can be pulled apart again - and repeated more maize without them tearing or other damage. It is on the finished tube, the place where the fold is very difficult u. U. not recognizable.

This effect is not achievable in a pipe according to the citation mentioned in the first place, there is also not recognizable, it is iedigiich recognizable that the fold is formed in a groove flank, the entire width of this edge overlaps and abuts on both sides of the adjacent flanks Thereafter it is obvious that when the flank angle is changed, when the tube is compressed (and subsequently re-pulled apart), bending of the adjacent tendrils occurs, which can not be reversed and already significantly hinders compression and restricts the adjacent grooves are deformed so that the tube is unusable or even ruptures - because yes, the deformation with a forced change in the pipe diameter, z. B. on a "groove mountain", (retraction inward) is connected

The second-mentioned prior art teaches only to produce a rebate, which is folded rohrachsparallel and so remains thereafter, therefore, it is only known that bring into engagement the angled sheet metal parts approximately in such a way to make as in the first two steps according to the invention Action. However, according to this state of the art, it can not be taught and no indication can be given that, in the case of a further incidence of the fold which is not shown there, the special possibility of folding the rib walls in the application process is to be effected The second prior art mentioned is namely not S5 such a compressible, fully flexible tube.

Characterized in that the or the folds are arranged in a tube according to the invention radially to the tube axis.

There is no longer a Nachfedern, so that the bending, squeezing and pulling apart of the tube without special effort is feasible and the given form is retained Since the peak compressive strength of the tube, especially at the folding of the tube is considerably improved, is such Pipe not only much more resistant to mechanical stress, but it can also be made of a thinner material for this reason.

Since according to the method of the invention in a simple manner, the possibility is given to produce two-layer pipes in which the individual layers are independent of each other, but by the tight Verrillung completely securely positively connected with each other, there is the possibility of such pipes much denser Run as before, because the folds are also lying in different places, completely independent of each other and have no connection with each other. In this regard, there have hitherto been considerable difficulties with such two-layer pipes. Since in a two-layer pipe according to the invention coated sheet or film strips can be processed without difficulty or even together with each strip parallel strips laid mis mis wrap other material, the invention provides the possibility for the production of pipes on the inside - and / or outside are provided with a further layer or coated, and in addition to that, they may have another layer or layer between the two layers. A tube according to the invention may thus have several different layers or layers in its wall.

The invention will be explained in more detail below with reference to embodiments with reference to the drawings in the drawings

Fig. Sa to d the procedure for the production of a liner groove tube according to the invention,

2a to 2g procedure for producing a two-layer tube,

3a to 3g procedure for producing a two-layer tube with an additional outer layer or cover layer

4a to 4g procedure for producing a two-layer pipe with an additional inner layer or cover layer

F i g. 5 procedure for producing a two-layer pipe with an additional layer or layer between the two layers.

According to the invention, strips of thin sheet or foil, initially unwound in the well-known manner, are made in a special device, but care is taken to ensure that a smooth area remains after the two edges, one of the two edges , and that at which a slightly wider smooth area remains is bent in the direction of the groove, and approximately at right angles, while a groove is formed in the other edge following a narrow, smooth area. A strip is formed as shown in FIG. 1 a in an interrupted manner in profile.

The central portion of this strip, generally designated 1, is provided with a number of longitudinal grooves 2. On one side of the strip, a wider area 3 remains undeformed, remained, the edge 4 is angled approximately at right angles in the direction of lying between the grooves 2 ribs 5 On the other

Side of the strip is a narrower, about half as wide area 6 remained undeformed, wherein the adjoining edge 7 of the strip is formed as a rib 8.

If the strip t is at one above the in F i g. la presented profile arranged core wound helical, in such a way that initially the winding is wound according to the left side of Fig. La and the winding according to the right side of Fig. La follows, so it forms formed on the edge 7 of the strip Rib 8 via the bend 4, as shown in Fig. La. As a result, a certain guidance for the strip is achieved even when winding the strip on the core

According to FIG. 1b, the rib δ with the bend 4 dipping in or hooking it in the direction of the wider, undeformed strip part 3, on which the bend is formed, is produced immediately after the winding process 4 arranged folded over and after complete folding, according to the Fig. Ic, pressed It can be seen that, corresponding to FIG. Ic has already formed a Verbindungsfalz 9 with simple undercut. Immediately thereafter, a further rib 10 is formed in the region of the now assembled and continuous wound strip in which the fold 9 is formed on the winding core according to the Fig. Id. The shaping of this rib is such that the fold 9 in one of its flanks If recorded. This then creates a double undercut seam and a tube that is continuously and evenly grooved - so it is no longer found that it is a wound from a single sheet metal strip and folded tube

In the F i g. 2a to 2g, the operation for producing a two-day pipe is shown in various steps; Again, there is the core on which the pre-grooved tape is wound to form a tube, each above the in the respective F i g. a to g profile cross-section shown. It will be appreciated that the first steps in making the tube are the same as in the above-described procedure for making a liner tube. According to FIG. 2a, a ribbon is first wound onto the core and its edges overlap with a rib 8 and a bend 4. Here, the same reference numerals apply mutatis mutandis as in the previously described AusführungsbeispieL

In F i g. 2b it is shown that the bend 4 at one edge of the band cross rib 8 is folded over to one side, to the side of the belt, at the edge of the bend 4 is arranged Here, the rib 8 is gradually compressed so that initially the two band edges 4 and 7 lie directly on top of each other and engage behind each other by the corresponding deformation and greater bending or undercutting.

After gradually folding the rib 8 under compression, the stage Fig. 2c is achieved by forming a fold 9 in the surface of the pipe immediately outside the winding mandrel, that is to say in the area of ​​the region 3 and 5 of the strip. Already at this stage another strip 12 wound on the formed on the winding mandrel tube with the strip 1 This further strip 12 is just pre-grooved with grooves 2 'and ribs 5'. The strip 12 also has at the rear edge in the winding direction an angled portion 4 ', wherein the distance 3' between the bend 4 'and the first rib 5' is substantially smaller than the distance 3 between the bend 4 and the first rib 5 of the first Volume 1.

After further winding of the tape 12 of the second layer, the image results in accordance with F i g. 2d. The opposite edge of the band 12 has been laid with its rib 8 'and its free outer flank 7 over the bend 4', so that the band is already positively connected at this edge. When placing this next winding of the tape 12 outside on the extent already finished tube that forms the inner layer is ensured that the wide, undeformed in the groove area 6 'of the band 12 of the second layer is formed over the fold 9 tight fitting. From the F i g. 2e and 2f it can be seen that then in the band Ί2 the second layer in the same way a Faiz 9 'gebii det, as was the case with the band 1 of the first layer. With gradual repackaging and compressing the rib 8 ', which overlaps the bend 4', the fold 9 'is formed. From the F i g. 2f it can be seen that the two folds 9 and 9 'are formed in the inner circumferential surface of the tube between undeformed, non-grooved portions of the wound tapes. These are the areas 3 and 6 of the band 1 and the areas 3 'and 6' of the band 2. In this case, the area 3 is originally as wide as the area 6 ', and the area 6 is originally as wide as the area 3'. The width of the areas is coordinated so that in the final molding of ribs, corresponding to the F i g. 2g, on the winding core, the molded-in folds 9 and 9 'form the flanks of two successive ribs 10 and 10'. It is therefore at the corresponding F i g. 2g finished tube optically no longer or only with very accurate examination to recognize that it is a folded tube and where these folds are. From the above figure is also readily apparent that the aforementioned advantages are given.

In the following figures, pipes produced in the basically same working method as in FIG. 2 are shown which consist of strips which are provided with coatings or supports on one or both sides. According to the F i g. 3 is used as a second outer band, a band which has a coating or overlay located on its later outer side, which is replaced by the parallel outer band.

so running dashed line is shown. This coating or overlay 13 may be of any suitable material, it may be in the form of a layer sprayed on or otherwise applied to the belt, but it may also be a film laid on or bonded to the belt. That according to the

F i g. 3g tube obtained is practically a three-layer pipe.

According to the way of working, based on the

Fig.2 is illustrated in Fig.4 the preparation of a

Pipe explains that also has three layers but wherein the third layer forms the inner layer and, for example, an insulation of the wall of the tube forms this wall protects against decaying attacks or heat or sound insulation causes It is the first aufgewikkeltes on the core band. 1 such a tape used that on the later inside with a support 14 in the form of a coating with paint, insulating or in shape

9

the individual steps of the method of operation in the production of the tube, as shown in FIG. F i g. 4a to 4g, are the same as detailed in FIG. 2 are described. From the representations reproduced here, it can be seen particularly clearly that an additional seal is to be formed by the third layer 14, in particular in the fold 9 on the first inner strip, so that an excellently sealed tube is formed. This has scarcely hitherto been the case with tubes of this type to reach. In this sense, a tube can be formed in which an inner support or coating is present only in the area of ​​the later fold, in order to obtain a one- or two-layer tube, which is equipped with a special rebate seal

According to the embodiment of F i g. 5 becomes the band responsible for the formation of the inner layer |

of the tube, provided with an outer support. I

This outer edition of the first band can already be applied in the production of the band, as in the above-described examples in connection with the F i g. 3 and 4, however, the outer pad 15 of the inner band may also be at the stage corresponding to FIG. 5c are wound before another to be folded tape is wound on the core and already there folded band. The support 15 then forms a second layer in the wall of the pipe and overlaps the already completed seam 9. In the layer 15, which later forms an intermediate layer between the two folded strips, it may be, for example, a nonwoven of non-combustible mineral fibers. so that this layer forms a heat and flame insulation Such a construction of a pipe can be extremely advantageous for example for exhaust pipes and internal combustion engines. I-I

If the two methods are considered together, several single-wound layers can also be arranged, which also have different physical properties.

For this 5 Blait drawings

45

50

55

eo

t> 5