EP1570926A1 - Method of making an elbow for a downpipe, an elbow piece and a downpipe - Google Patents

Abstract

A process fabricates a pipe elbow for a rainwater drainpipe made of sheet metal with a longitudinal seam weld. A series of ribs are pressed on one side of the sheet metal at regular intervals.

Description

Technical area

The invention relates to a method for producing a pipe bend for a standard pipe, a pipe elbow as an extension for a downpipe and a downpipe.

State of the art

Biegesteife, inflexible elbows, so-called manifold, for downpipes typically have a wall thickness of 0.4 mm to 1 mm, preferably between 0.4 mm and 0.9 mm and a diameter between typically 50 mm and 150 mm, wherein standardization to a diameter of 50 mm, 60 mm, 75 mm, 80 mm, 100 mm, 120 mm and 150 mm. The diameter values of 60 mm, 75 mm, 80mm and 100 mm are preferably used. Pipe bends have been preformed from two Half shells produced, which then by folding or welding together get connected.

To circumvent this labor-intensive procedure, IT-B 12 68 951 proposed from a straight, welded pipe with a length between 100 mm and 1500 mm to go out. The ends of the straight tube were grasped with gripper units and with a force of 1 t to 2.5 t under simultaneous pulling and twisting action bent in a shape. The mold had a molding for the outer and one for the inner pipe bend. On the molding for the outer arch part worked one Compressive force of 17 t and on the molding for the inner arch part a force of 13 t. With this method, pipe bends between 40 ° and 90 ° (Sexagesimalsystem) getting produced. A production of elbows according to this production method was complicated and complicated.

Presentation of the invention task

The object of the invention is to provide a simple method for producing a rigid, inflexible pipe bend on and for downpipes and thus a low-priced To create pipe elbow or a downpipe.

Under a completely closed, rigid, inflexible thin-walled Sheet metal pipe is understood to mean a pipe whose shell has peripheral forces, ie tensile and Pressure forces under elastic and plastic strain can absorb. That of the Pipe jacket is not just bent together, in which case the two longitudinal Sheath edge areas overlap one another and possibly would be prevented by a rivet on the gap gape.

In a fully closed, rigid, inflexible in the circumferential sheet metal pipe are usually the ends of the casing longitudinal edges with a TIG ( "Tungsten - Hertford G as") - or TIG (W olfram- I nert- G as) method butt-welded , It could also be a so-called seamless pipe, but these are more expensive to manufacture relative to the welded ones. It can also be a connected with a Längsfalz tube hereunder, provided that this compound can absorb coaxial pressure and tensile forces. In a completely closed sheet metal tube coaxial pressure and tensile forces cause only a circumferential enlargement due to a plastic or elastic strain; a widening of the circumference, caused by longitudinal edge areas sliding on one another or rising of a slit, is excluded.

For TIG connection methods can similarly a GTAW (G as T ungsten A rc W elding), a GMAW (metal inert / active gas welding), a MIG (m etal_hert g as) -, a MAG (m etal a ctive g as) method can be used as a connection method. MMA ( m anual m etal a rc welding) will probably not apply for cost reasons.

solution

The object is achieved by the features of claim 1 concerning a manufacturing process. A produced by the inventive method tube sheet piece according to the invention is characterized by the features of claim 6 Are defined. Claim 9 defines a rainfall pipe according to the invention.

The tube sheet pieces and downpipes according to the invention are in a preferred manner Spenglereiartikel; However, they can also be used in other areas. she however, are not to be confused with so-called flexible hoses, as e.g. in the ventilation technology can be used as extractor pipes. The inventive Pipe elbows and downpipes are waterproof. The flexible "extractor pipes" These are not usually.

In the invention, a first groove with continuous material transitions is pressed in a completely closed, rigid, inflexible, thin-walled pipe in a completely closed in the shell circumference pipe bend to produce a pipe curvature. This groove pushes through the sheet, whereupon on the other sheet side (the other side of the shell) forms a corresponding bead. In a rough approximation, it can be said that the groove or the associated bead, since the sheet thickness is negligible in relation to the deformation, have a Gaussian, sinusoidal ^2- shaped,... Cross-sectional course (parallel to the tube axis). When pressing in this groove results already along a parallel to the tube axis generating line a path extension, which is somewhat reduced by a plastic deformation of material, but for the most part causes an angling of the previously straight pipe. If the tube is clamped annularly when Nuteneinpressen results in a strain, which causes a deflection at then released pipe.

In a next step, then the bead sides are compressed, so that a Bridge is created. The squeezed bead sides are now down to a tolerance adjacent web walls. Completely, the web walls do not abut each other, because when plastic compression always an elastic part remains, the low Springs open ("tolerance"). By pressing another is done Wegverkürzung along the local Mantellängslinie. As the Nuteneinpressung not has been made completely circumferential, carried by the Stegerzeugung on one side of the pipe shortening the path and on the other side no shortening of the path, whereby a pipe angle is achieved.

Instead of letting the groove rotate only partially, the pressed-in groove can also be complete circulate. It is only necessary to ensure that in the place where the complete bent pipe later the pipe inner bow should come to rest, a maximum Groove depth is pressed in and opposite (= pipe outer arc) a minimum groove depth. Such Nuteneinpressen can, for example, by the bending process in question be predetermined. Also can be a special aesthetic Effect to be desired.

The finished bent pipe can only, provided the webs on the outer surface of the pipe lie, abut the web vertex edges to the holder. For example, because a heat conduction over the webs opposite a heat conduction over a fully fitting Coat is reduced, it may be advantageous for heat insulation such a holder make. If a heat-insulating holder is desired, of course with the below-described method also circumferential grooves with the same Groove depth (= same web height) are pressed to a wall distance as well to achieve a straight pipe section. In addition to a "thermal insulation" can also a reduction of the sound transmission to wall areas can be achieved.

In the selection of the groove depth one is relatively free. For aesthetic reasons can be set when selecting the groove depth and the groove width limits. Also the free cross-section decreases due to the grooving and crimping of the groove Bulge, which is easy to visualize in a 90 ° bend. Theoretically and in practice, however, it is possible to choose the geometry of a groove such that a 90 ° bend is achievable.

The ridges to the pressed-in grooves do not have to be complete (except for one tolerance) be pressed together. Also, in the circumferential course steadily increasing compression e.g. made at a groove with circumferential groove depth same become. However, a compression of the grooves is to be made in any case, as thereby the degree of angulation can be increased; In addition, the torsional rigidity also increases of the pipe.

For the above-mentioned aesthetic reasons and due to a good liquid passage however, one will seek an approximately continuous bend, composed of smaller bends, to reach. It is therefore, distanced from the first groove equally generates a second groove in the same way and then following grooves until the desired total bending is reached.

The webs can be arranged on the outside of the tube, but they can also lying in the pipe. An arrangement inside the tube can have aesthetic reasons but also be used, for example, to swirl the flow or the Decelerate flow velocity.

The groove or the grooves can now in the pipe jacket from the inside to the outside or pressed from the outside inwards. Be the grooves from the outside to the inside pressed in, must be inside the pipe at the Einpressort left and right next to the einzupressenden Groove a counterhold be present; otherwise the tube would become uncontrolled buckled. Also would have the squeezing the bead sides to a Bridge in the tube interior done.

It is easier to press the groove from the inside of the tube to the outside. It could then namely waived on the counterpart. However, the backstops can also here, as described in the embodiment, abut the pipe inside. Lie the anvils closed annular over the entire Nutenrandbereich, can to dispense with a voltage applied to the outside counterhold. In the actual Meaning of the word is then no longer a counterpart, but around a kind of clamping jaws. The tube is in fact stabilized inside, so no Wrinkling occurs. However, the backstops can also be arranged on the outside of the tube become; the groove is then nicely shaped.

When squeezing each one bead to a bridge, arises opposite the groove / Wulsteinprägung a significantly larger Teilabbiegewinkel. At this partial angling Make sure that at least one pipe end is free. There the turn is largely done at the bridge formation, it is also important to ensure that at least one of the sides of the bead edges attacking crimping jaws in the direction the predetermined partial angling of this following is formed pivotable.

If the pipe bend is to be done in one plane, then you assign the places maximum groove depth in a plane in which the tube axis is located.

As stated above, can be proceeded such that the groove bottom on a Circle is, whose radius is the pipe radius + 1/2 of the maximum groove depth, where the center of the "groove bottom circle" of the pipe axis by 1/2 of the maximum Groove depth is offset toward the location of the minimum pipe bending radius out. The thus obtained tube sheet piece is geometrically a portion of an approximated circular torus, provided that the distances of the individual grooves are the same. The geometric approximation to a portion of a circular Torusstückes is therefore given because the turning process is a juxtaposition of Teilabwinkelungen is, wherein the compounds, in particular the places with the web height zero at the Rohraussenbogen Strictly speaking straight line pieces are. A smearing of the line takes place by a continuous transition between the individual straight line pieces, caused by the bending and squeezing process.

If now the distance between the webs is increased or decreased, the result is in the mass the enlargement or the reduction an enlargement or reduction of the Pipe bending radius (= pipe bend radius). Also a reduction of the groove depth or the web height results in a constant web distance an enlargement the bending radius; an enlargement therefore results in a bending radius enlargement. By a variation of the groove depth and / or their mutual distance can be a Bend radius variation can be generated.

The tube axis and the center of the "groove bottom circle" do not have to be in one plane lie. If the position of the center of the "groove bottom circle" is rotated to the tube axis, also results in a rotation of the bend. In this way you can Pipe bends are generated with a curved bend.

Of course, as well as making a curved arch Elbows are made with distanced bends from each other. It can thus For example, U-shaped and S-shaped bent tubes, or so-called floor arches become.

An inventive pipe elbow piece, which according to the above-described method is prepared, can serve as a fitting for a downpipe. This pipe elbow piece is a circumferentially completely closed, thin-walled metal tube and thus completely leakproof for liquids (and even gases), especially rainwater. In the pipe bend region of the minimum pipe bend radius is at least one material web made of pipe wall material available. The web walls of the material web are preferably except for a tolerance to each other. The web height of each material web takes in the circumferential direction of the pipe bend area with the larger pipe bend radius continuously down to zero. The at least one material web is preferably on the Rohrmantelaussenseite, but it does not have, as already stated above. Depending on predetermined total pipe bend are more beaded together to webs distanced in the direction of the pipe axis. For the pipe bend piece apply the statements made in advance to the manufacturing process by analogy.

A rainwater drain, for example, starting from a gutter, can over a gutter box, a piece of pipe elbow or more pipe elbow pieces and a rainfall pipe or several straight downpipes are put together. With a manufacturing method described above can now inventive integral, one-piece downpipes made with at least one bend become. These integral downpipes also have a completely closed, thin-walled sheet metal tube with e.g. a longitudinally welded pipe jacket. The downpipe has at least one straight and at least one curved Pipe area. This downpipe, with straight part and bend, is one piece without Transition joint, without transition welding, without Übergangsverlötung and formed without transition bonding. At the transition from straight to curved Pipe part is at least one web present, the web height at Rohrbiegeinnenradius maximum and at the Rohrbiegeaussenradius is preferably vanishing. Depending on the given Pipe bending are more distant webs available. One Such integral downpipe is made of a straight piece of pipe through the top described generation of rib-like bending sections, resulting in one and the same tube produced in a simple manner fluid-tight transition from the straight to the bent part is possible.

The downpipe can have an integrated pipe bend at only one end area to have. But it can also rainfall pipe at any end in one Direction curved integrated pipe bend have. Thus, so-called Shelf pipes are manufactured in one piece, whereby also these pipe bends may have another bend.

From the following detailed description and the totality of the claims result in further advantageous embodiments and feature combinations of Invention.

Brief description of the drawings

Fig. 1

eine Draufsicht auf ein mit dem erfindungsgemässen Verfahren hergestelltes Rohrbogenstück,

Fig. 2

einen Querschnitt durch das in Figur 1 dargestellte Rohrbogenstück entlang der Linie II - II, wobei hier die Rohrwandstärke überhöht dargestellt ist,

Fig. 3

eine Draufsicht auf eine Variante zum in Figur 1 gezeigten Rohrbogenstück in einer U-förmigen Ausbildung, wobei die Achse des gesamten Rohrbogenstücks in einer Ebene liegt,

Fig. 4

eine Draufsicht auf eine Variante zum in Figur 1 gezeigten Rohrbogenstück in einer S-förmigen Ausbildung, wobei die Achse des gesamten Rohrbogenstücks in einer Ebene liegt,

Fig. 5

eine Draufsicht auf eine Variante zum in Figur 4 dargestellten Rohrbogenstück in einer Ausführung als sogenannter Etagenbogen,

Fig. 6

eine Draufsicht auf eine Variante zum in Figur 3 gezeigten Rohrbogenstück, wobei die Achse des gesamten Rohrbogenstücks nicht mehr in einer Ebene, sondern im Raum gekrümmt liegt, d.h. die Rohrachse des Eingangs des Rohrbogenstücks liegt hier beispielsweise senkrecht zur Achse des Ausgangsstükkes,

Fig. 7

eine Draufsicht auf ein integrales Regenfallrohr mit einem integrierten Rohrbogenstück,

Fig. 8

eine Draufsicht auf eine Ringmatrize, welche zur Erzeugung der erfindungsgemässen Rohrbiegung in den Innenraum des zu biegenden Rohrs zu schieben ist, und

Fig. 9

eine Draufsicht auf eine Rohrbiegevorrichtung in weit geöffneten Zustand mit der in Figur 8 dargestellten Ringmatrize.

The drawings used to explain the embodiments show in

Fig. 1

a plan view of a produced with the inventive method pipe elbow piece,

Fig. 2

3 shows a cross section through the pipe bend piece shown in FIG. 1 along the line II-II, wherein here the pipe wall thickness is shown in an exaggerated manner,

Fig. 3

1 shows a plan view of a variant of the pipe bend piece shown in FIG. 1 in a U-shaped configuration, wherein the axis of the entire pipe bend piece lies in one plane,

Fig. 4

1 is a plan view of a variant of the pipe bend piece shown in FIG. 1 in an S-shaped configuration, wherein the axis of the entire pipe bend piece lies in one plane,

Fig. 5

4 is a top view of a variant of the pipe elbow shown in FIG. 4 in a design as a so-called floor arch,

Fig. 6

3 is a plan view of a variant of the pipe bend piece shown in FIG. 3 , wherein the axis of the entire pipe bend piece is no longer curved in a plane but in space, ie the pipe axis of the entrance of the pipe bend piece is here for example perpendicular to the axis of the output piece.

Fig. 7

a top view of an integral downpipe with an integrated pipe elbow piece,

Fig. 8

a plan view of a ring die, which is to push for generating the pipe bend according to the invention in the interior of the pipe to be bent, and

Fig. 9

a plan view of a pipe bending device in the wide open state with the ring die shown in Figure 8 .

Ways to carry out the invention

The pipe bend piece 1 shown in FIG. 1 in an embodiment variant of the invention is designed as an 85 ° bend with a bend angle δ of 85 °. 85 ° and not 90 ° are selected so that the rainwater carried in the pipes can drain properly. The tube sheet piece 1 can be used as a fitting for a rainfall pipe. The tube sheet piece is a circumferentially completely closed, thin-walled sheet metal tube 2. The tube shell 3 is here due to a TIG longitudinal welding 6 ( Figure 2 ), a circumferentially completely closed sheet metal tube with a typical wall thickness of 0.4 mm to 0.8 mm. In the pipe bend area 4, which here has an angle of 90 °, for example, there are ten webs 5 on the outside of the pipe jacket. The web height s decreases continuously from a maximum value at the inner pipe bend 7 with the minimum pipe bend radius (pipe bend inner radius) down to zero to the pipe outer bend 9 with the maximum pipe bend radius (pipe bend outer radius). The lateral web walls 11a and 11b abut each other to a tolerance. Are less than ten material webs 5 present, resulting in the same maximum web height s and the same mutual distance d of the webs 5 (unpressed state) a smaller turn angle δ than 90 ° and at a larger number of webs 5 a larger turn angle δ. Except for a closed pipe elbow (torus) can be produced depending on the number of webs used any 5 pipe bends. In plumbing, pipe bends with a bend of 40 °, 70 ° and 85 ° are preferred.

A pipe bend piece can now, as shown in Figure 1 , as a pipe bend piece with a single bend, the turn angle δ on the number of material webs 5, the height and the mutual distances depends are produced. The turning angle δ also still depends on the degree of compression of the two web walls 11a and 11b of each web 5 against each other; However, for the sake of simplicity, one will always make a complete pressing together of the web walls 11a and 11b , in which case a gap which is merely based on the remaining elasticity remains between the two web walls 11a and 11b . The tube axis of the pipe bend shown in FIG. 1 runs parallel to the plane of the drawing.

A pipe bend piece can also, as shown in Figure 3 , as an integral U-shaped pipe elbow piece 15 with two bends, which here, for example, also have a bending angle δ of 85 °, are formed. It is understood here in one piece, that this U-shaped pipe elbow piece is made of a single straight eg longitudinally welded pipe piece. The two bends 17a and 17b are thus neither put together, nor welded, nor soldered, still glued together and not connected by a fold. Again, the tube axis 18 of the U-shaped pipe elbow extends in a plane parallel to the plane.

If the bending direction is changed by 180 ° in one of the bends 17a and 17b , as explained below, an S-shaped pipe bend piece is obtained, wherein the entire tube axis course of the pipe bend can lie in one plane (pipe bend piece 21 in FIG Pipe bend axis 22 in a plane parallel to the plane). It can also, as Figure 5 shows, the bending direction within the bend 24a, so without an interposition of a straight pipe section, go into a different type of bend 24b . Such merging bends are needed in so-called floor tubes 24c .

But it can also be an angulation of 85 °, for example, as in the pipe elbow 25 of Figure 6, made. In the pipe bend 25 shown in Figure 6 , the pipe bend axis 26 extends in two mutually perpendicular planes. Analogous to the production of a pipe bend piece 1, 15, 21 or 25 , a rainfall pipe 29 (FIG. 7) with an integrated bend 31 or several bends can also be produced. That is, in such a downpipe at least one straight and at least one bent pipe portion 30 and 31 integrated into a one-piece downpipe is present.

The pipe sections 15, 21, and 25 and the rainfall pipe 29 with integrated bend or integrated bends can be produced only with the manufacturing method described below, but not with the method of the above-mentioned IT-B 12 68 951.

For producing the above-described pipe sections 1, 15, 21 and 25 or the rainfall pipe 29 with integral bends, the ring die 37 shown in a top view in FIG. 8 is inserted, for example, into a sheet-metal tube 2 ( FIG. 2 ). The ring die 37 has from right to left in Figure 8 a fitting piece 39 for installation in a Rohrabbiegevorrichtung, a tube inner diameter of the pipe to be bent except for a clearance fit counter-holder 41 , a Nuteneinpresseinheit 43 and two other mutually braced, analogous to the backstop 41 at the tube inner diameter adapted counter-holder 45 and 47th

A pull / push rod 49 (FIG. 9) engages approximately centrally through all parts 45, 47, 53 and 41 . The Nuteneinpresseinheit 43 has a raised Nutenmatrize 53 , which corresponds to the shape of the grooved Nutenverlaufes. The Nuteneinpresseinheit 43 is annular and consists of several ring segments, in which case of a preferred division into four ring segments only the ring segments 55a and 55b are visible. All ring segments are radially spreadable by an unillustrated inner conical force transmission element by an axial movement of the pull / push rod 49 to the outside; whereby then a groove with the predetermined depth profile can be pressed into the pipe inner shell. The two adjacent counter-holders 45 and 47 are also annular in shape; by its central region engages also the push / pull rod 49. The two counter-holders 45 and 47 have in the initial state shown in Figure 8 each have a nearly to the axis of the ring die 37 vertically extending, oppositely facing outer surfaces 59 and 60th The rest state shown in the two figures 8 and 8 of the two counter-holder 45 and 47 is obtained by two between two counter-holders 45 and 47 acting (not visible) compression springs. The mutually facing surfaces 61 and 62 of the two counter-holders 45 and 7 have an angle β to the respective outer surfaces 59 and 60, respectively. That is, between the two surfaces 61 and 62 , a downwardly converging gap 63 is present. This column 63 is necessary to produce, as explained below, in each case a partial angling in the pipe bend generation.

An example bending device with the ring die 37 described above, Figure 9 shows a perspective oblique view. The bender has, as seen in Figure 9 , from right to left two split jaws 69a and 69b and a clamping member 70 which is movable in synchronism with the jaws 69a and 69b . Between a cylindrical, horizontally lying support unit 68 and the jaws 69a and 69b , a ring slot 67 is present, from which out of the bent sheet metal tube 2 can be pulled. The sheet metal tube 2 is clamped on the support unit 68 with the jaws 69a and 69b and the clamping member 70 during the groove embossing and the bending operation. After the left, two further open, shown, mutually movable jaws 72a and 72b are present. Both jaws 72a and 72b have an annular recess 71a and 71b, which give space for a groove in the forming groove in the pipe jacket. The jaws 72a and 72b are located locally in the radial peripheral area of the grooved die 53 . Farther outward follow two further mutually movable clamping jaws 73a and 73b, which are arranged locally in the radial peripheral region of the counter-holder 45 .

For producing a pipe bend 1, 15, 21, 25, 27 and 31 , the location of the beginning of bending on a pipe 2 is brought to the location of the grooved die 53 . The outer shell of the tube 2 is pressed with the two jaws 69a and 69b and with the clamping element 70 on the support unit 68 . The two jaws 72a and 72b are respectively above the Nutenmatrize 53 that the sheet metal tube 2 at a groove edge to be generated between the right in Figure 9 boundary of the recesses 71a / b and the top of the backstop 41 and between the left boundary of the recess 71a / b and the top of the counter-holder 47 is clamped. By a pulling movement of the push / pull rod 49 , the ring segments 55a and 55b (and possibly further) of the Nuteneinpresseinheit 43 are now "inflated", whereupon a groove is pressed into the tube interior, which results in a corresponding bead on the outside of the tube, in the recesses 71a / b comes to rest.

In a subsequent operation, all clamping jaws 71a, 71b, 73a, 73b and the clamping element 70 are released and the Nutenmatrize 53 retracted to its rest position. The sheet metal tube 2 is moved out of the annular slot 67 by a distance d . It follows a further operation, in which a clamping around the Nutenmatrize 53 around, as already described, again takes place. At the same time but one of the clamp is now carried out a groove or a Wust having further pushed the tube part by means of the jaws 73a and 73b against the counter holder 45th The pull / push rod 49 is now retracted, with a Nuten- / bead forming as described above, takes place. At the same time pulling the push / pull rod 49, the counter-holder 45 with the jaws 73 a / b in, ie in the direction of the Nutenmatrize 53. Since the two counter-holder 45 and 47, as shown in Figure 8 , are wedge-shaped, and the greatest distance of two counter-holder 45 and 47 coincides in the axial direction with the maximum groove width, the deepest formed and thus the widest bead is squeezed together under a pipe angle according to the wedge formation of the anvil 45 and 47 the strongest. The jaws 73a and 73b are pivotally supported so that they can follow the Abwinkelungsvorgang.

The groove / bead formation and web formation now always take place at one and the same Operation, with always a pinch of the generated by the previous groove formation Bead occurs.

The course of pressed groove or protruding bead schematically shows Figure 2. Figure 2 shows the material web 5; However, the Nuten- or bead course is similar in a cross-sectional view, wherein the non-compressed bead, the bead height is lower than the web height. The Nuteneinpresseinheit 43 has now generated a groove, the groove bottom (location of the largest depression) is located on a circle with a radius r ₁ , wherein r ₁ is greater than the value of half a maximum groove depth than the radius r _{2 of} the unprocessed inner diameter of the sheet metal tube second and the circle of radius r _{1 is} tangent to the circle of radius r ₂ at location T of the predetermined maximum bend radius. The center of the undeformed pipe diameter is M ₂ and that of the Nuteneinpressung M ₁ . After the above-described compression of the bead results in an elevation. The maximum web height above the tube circumference is now only approximately a circle; Strictly speaking, the distance of the web edge from the point M ₁ : r ₁ + Δ (φ) .Δ (φ) should indicate an angular dependence, wherein in the lower part of Figure 2 at a vanishingly small ridge height r ₁ = r ₂ . The deviation then increases continuously. The circumference is thus not a circle, but an ellipse.

If a completely circumferential groove is formed, as mentioned above, applies analogous. Again, the pressed-Nutenring has a staggered circle center, if one Bending is to be caused. Shall only a holding bar in a straight piece of pipe are generated, the two circle centers coincide. By the following Pressing the bead to the web then results in a radius enlargement, but no deformation to an ellipse.

The sheet metal tube is preferably made of copper, zinc sheet, stainless steel, aluminum or galvanized sheet iron.

In the bending process for sheet metal tubes described above, a complicated Interaction of plastic deformations, which in both radial and in Act longitudinal direction on the jacket of the sheet metal tube. The plasticity of one in his The extent of completely closed pipe, a so-called circular pipe, is a problem higher technical mechanics (see, for example, István Szabö, "Higher Technical Mechanics ", Springer Verlag 1960, p. 150, p. 240).

The indentation of beads of different width and height and their compression for the production of webs, which in turn should produce a pipe bend, are by no means obvious starting from IT-B 12 68 951. If any, The expert would then theoretically with a longitudinal slit Working pipe whose pipe wall bent to a pipe at a pipe end is held together with a rivet or the like against unfolding. This A longitudinally slit tube would be the expert before complicated considerations free the circumferential forces occurring in the pipe jacket, which leads to a tearing could cause the tube shell or wrinkling.

Surprisingly, however, the above-described method has an easy-to-perform Production of Blechrohrbiegungen revealed. The process is inexpensive and gives aesthetically beautiful pipe bends.

The above-described ring die with the Nutenmatrize and the counter-holders and the various jaws must be adapted to the groove / bead formation and the subsequent web production of the respective pipe diameter. In order not to have to make a complete set of dies for each pipe diameter, parts of the jaws can be made adaptable by inserts. Such threaded inserts utilize the device shown in FIG . However, the backstops 45 and 47 will usually always be replaced, since these are simple and therefore inexpensive parts. Since the plumber knows a diameter deformation in roof drainpipes, also keep Matrikesätze within limits.

Claims (11)

A method for producing a pipe bend (1; 17a / b; 23a / b; 27a / b; 31) for a downpipe (29), wherein the pipe bend (1; 17a / b; 23a / b; 27a / b; 31) a Completely closed, rigid, inflexible, thin-walled sheet metal tube (2) with eg a longitudinally welded tube shell (3) , characterized in that a first at least partially circumferential groove under a plastic deformation in a predetermined pipe jacket region of a rigid, inflexible pipe with a maximum and one of these opposite minimum groove depth is pressed, wherein the groove forms a rib-like protruding bead on the other shell side, and then this bead is squeezed together to form a web (5) , whereupon a pipe bend results, and that depending on the required total pipe bend further to Webs (5) squeezed beads in the direction of the tube axis (12; 18; 22; 26) progressively distanced from the last zusa mssenquetschen bead, are produced in the same way. A method according to claim 1, characterized in that each groove from the inside of the tube forth outwardly bulging in the tube shell (3) is pressed. A method according to claim 1 or 2, characterized in that the web formation on both sides of the bead at each edge of a bead base clamping with an axial reduction in distance is made, wherein a clamp is pivoted during the collision against the other to produce a Abbiegeteilwinkel. Method according to one of claims 1 to 3, characterized in that after the pressing of at least one partially circumferential groove and a subsequent squeezing of the bead formed by the groove, the sheet metal tube is rotated about its tube axis (26) to a twisted bent pipe bend (25 ), wherein the rotation of the tube about its axis takes place after an axial tube movement. Method according to one of Claims 1 to 4, characterized in that at least three grooves are pressed in and the beads formed by grooves are squeezed together, grooves having predetermined, differing maximum groove depths being pressed in and / or the bead or groove distances being selected differently to produce a pipe bend with different bending radii, wherein the bending radius of the groove depth and width and their mutual distance depends. A rigid, inflexible pipe bend piece (1; 15; 21; 25) as a rain drop pipe fitting made by a method according to any one of claims 1 to 5, wherein the pipe bend piece (1; 15; 21; 25) is a circumferentially completely closed, rigid, inflexible, thin-walled sheet metal tube (2) with z. B. a längsverschweissten pipe jacket, characterized in that in the pipe bend area (4) of the pipe inner wall at least one material web ( 5) is provided from tube wall material whose web walls (11 a, 11 b) rest against each other to a tolerance and the web height in the circumferential direction to the pipe eye arc towards continuously decreases to zero and the at least one material web (5) is preferably located on the outer tube side, wherein depending on the given total pipe bending more to webs (5) squeezed together beads in Rohrachsrichtung are progressively available. Pipe bend piece according to claim 6, characterized in that a plurality of webs (5) are present and the web height and / or the mutual web distance (d) is predetermined according to the predetermined bending radius course. Pipe bend piece (25) according to claim 6 or 7, characterized in that a plurality of webs (5) are present and the locations of the maximum web height are laterally offset from each other for a curved pipe bend. Rainfall pipe (29) with a circumferentially completely closed, rigid, inflexible, thin-walled sheet metal tube with eg a longitudinally welded pipe jacket, prepared according to a method according to one of claims 1 to 5, characterized in that the downpipe (29) at least one straight and at least one curved pipe portion (30, 31) , the downpipe (29) is integrally formed without transitional connection, without Übergangsverschweissung, without Übergangsverlötung and without Übergangsverklebung, and at the transition from straight to bent pipe part at least one web is present, the web height at the inner pipe bending radius and at Rohrbiegeaussenradius is vanishing and depending on the predetermined pipe bend further spaced webs are available. Downpipe according to claim 9, characterized in that in at least one bent pipe region, the locations of maximum web height with respect to the pipe axis are rotated to produce a twisted course. Downpipe according to claim 9 or 10, characterized by at least two curved pipe sections, wherein the places maximum web height of a pipe bend area are pivoted laterally relative to the locations of maximum web height of another pipe bend area in the pipe axis, whereby the rainfall pipe axis is guided out of a plane.

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