DE102004025331A1 - Assembly to bond flat sections together along their butting edges, to form a three-dimensional hollow body, has carriers to support them for a hot air welding head to weld them at points along the joint between them - Google Patents

Abstract

The assembly to bond flat sections (1,2) together at their edges, to form a hollow body, has carriers (3,4) to support each section along their butting lines. A working head (20), especially a hot air welding unit, bonds (1,2) at least at one point (21) on their butting line, and either moves along the joint between (1,2) or they are moved under the welding head. Each (3,4) has a number of swing segments (8d-8f) as retainers (5,6), with at least two free swing degrees.

Description

The The present invention relates to a working device for edge-side joining from blanks made of flat material, from these a given three-dimensional hollow body produce, as well as a working method, with such a Device is executable. If two non-congruent edges of such two-dimensional flat blanks are to be interconnected continuously, so this is only possible if the resulting connection line or at the connection line connected blanks a curvature in a third dimension. As a hollow body should here in the most general Meaning every three-dimensional body be understood, the one compared to its other dimensions low wall thickness and at least locally concave.

One known working device, with the conventionally non-congruent edges of blanks is a sewing machine. This one usually has a head that has a needle moving up and down and a vertical one adjustable clamp foot wearing, the to serve the blanks to be processed against a flat carrier to press, in which on both sides of the needle two friction plates are movable, when sewing promote the blanks to be processed. To deal with such Machine curved margins to sew together it requires the constant Corrective intervention of an operator, the cuts across to the conveying direction tracks the friction plates. The when sewing of non-congruent edges resulting curvature the sewn Lead areas too tensions in the blanks, which makes a very tight stitching make difficult. The ones from sewing machines known technique for conveying The blanks is therefore not suitable when large format Blanks of a little stretchy material connected together should be.

task the present invention is to provide an implement and a method, which allow blanks with non-congruent edges their edges with the highest degree of precision too connect to a hollow body of predetermined three-dimensional shape from the blanks exactly put together.

The Task is solved on the one hand through a working device with two straps extending on either side of a boundary line for Support each of a blank and at least one working head for connecting that of the porters supported blanks at least one location of the boundary line characterized is that the carrier are each made up of a plurality of pivotable segments, which up to at most each have at least two pivot degrees of freedom.

With Help of these segments it is possible with every carrier approximately a section of a conical surface so that the line of intersection of the two conical surfaces of the two carriers at the point to be connected the for this point given curvature the two interconnected edges of the blanks in the three-dimensional Room of the finished three-dimensional hollow body has and the cutting angle the conical surfaces at the connection point the corresponding intersection angle of the three-dimensional hollow body equivalent. The shaped carrier support the blanks in each adapted to the shape to be produced wise, leaving the edges the blanks already touch each other before joining and essentially no manual correction is required. The weight interconnected areas of the two blanks is due this position of the carrier from the latter completely so caught during connecting forces not oriented transversely to the edges in the Blanks occur that move them against each other and one exact manufacturing could make it so difficult.

one According to a first embodiment of the invention, the working head is along the borderline between the bearers movable, so after once adjusting the segments and placing the blanks on this one on a substantially the length of the Limit line corresponding length can be connected to each other.

one According to a preferred embodiment, the carriers are provided with drive means for Promote equipped to the sections along the borderline. These drive means allow it, on a mobility of the working head along the To dispense with the boundary line and the process of connecting continuously make, even if the length the edges to be joined greater than the carrier is.

In order to guide each blank exactly in a designated direction so that the edge of the blank moves exactly on the boundary line, conveyor rollers are mounted on the supports at at least two different distances from the boundary line, and these are dependent on their distance from the Boundary line of different speed drivable to simultaneously rotate a blank during conveying. The strength of the rotation or the ratio of the speeds of the conveyor rollers of a carrier is advantageously determined depending on the radius of curvature of the edge of the relevant blank at the location of the working head so that this edge itself always moved in the same direction along the working head.

Preferably the segments are at least one of the carrier by hinged together Plates formed.

Preferably the plates are trapezoidal and each along the long baselines of the trapezoidal plates connected. This shape allows the carrier to be elongated in plan view To deflect configuration in two opposite directions.

Preferably is the long baseline of the trapezoidal plates of the boundary line turned to one as possible complete support to ensure blanks along the borderline.

alternative At least one of the carriers may also have a comb-shaped slit Include plate of a flexible material, wherein the segments each through the teeth this comb shape are formed.

Around an exact adaptation of the three-dimensional curvature of a blank that of his carrier to ensure, is preferably this carrier associated with a hold-down, like the carrier of a plurality of hinged segments is constructed and together with the carrier a guide gap for one Cut defined.

A exact promotion the blank between carrier and hold-down is achieved by having each conveyor roller of the carrier with an opposite one conveyor roller the blank holder forms a gap in which the blank can be clamped is.

When Working head for the implement comes in principle Any suitable for joining the edges of flat material blanks suitable tool, from a tape dispenser over a sewing machine head right up to a welding head. In order to weld blanks made of plastic material, in particular a hot air jet welding head is preferred.

The welding can in the case of polymer flat material, in particular calendered films, lead to a shrinkage of the material. To this shrinkage to prevent or compensate in advance, is preferably a first formed by two rollers gap in the conveying direction of the blank before the location of the welding head and a second gap formed by two rollers behind the place of the welding head arranged, and the rollers of the second gap are faster than that of the first gap is driven to the cut at the place of welding head longitudinal stretch of the edge, thus by the shrinkage of the material after welding the originals Dimensions of blanks as accurately as possible be achieved again.

Around after welding reduce stress remaining in the material of the blanks, a heat treatment zone is preferably provided on the implement, in the conveying direction behind the welding head is arranged so that they pass from the edges of the blanks after welding becomes.

Around the tightness of the weld to consider, is about it also preferably in the conveying direction behind the place of the welding head a spark discharge path or an ultrasonic testing device intended.

Of Further is expediently a material tension tester provided in for alone known manner, preferably by Un examination of Stress - induced birefringence, the assessment of in the Weld and allowed their environment voltages.

To the Pivoting the segments of the carriers each in adaptation to the known, predetermined course of interconnected edges in the three-dimensional hollow body is preferably a plurality of by an electronic control unit provided controlled actuators.

If the implement conveyor rollers to promote having the blanks, the control unit is expediently adapted to continuously adjust the position of the segments during conveyance, so that the course of the edges the blanks on both sides of the working head, that is before and after connecting, if possible exactly for the to be produced hollow body predetermined form corresponds.

• a) Festlegen eines Paares von miteinander zu verbindenden Punkten der Ränder von zwei flachen Zuschnitten;
• b) Ermitteln der lokalen Krümmung der als miteinander verbunden angenommenen Ränder der zwei als zu dem dreidimensionalen Hohlkörper zusammengefügt angenommenen Zuschnitte am Ort des in Schritt a) festgelegten Paares von Punkten und des Schnittwinkels der Zuschnitte am Ort des Paares von Punkten;
• c) für jeden der zwei Zuschnitte Formen eines Trägers, der einen Ausschnitt aus einem Kegelmantel approximiert, wobei die Kegelmäntel der zwei Träger einander an einem Ort mit dem ermittelten Schnittwinkel schneiden und die Schnittlinie die ermittelte lokale Krümmung ausweist; und
• d) Platzieren jedes Zuschnittes auf seinem Träger, so dass die festgelegten Punkte ihrer Ränder einander an dem Ort berühren, und Verbinden der Punkte miteinander.

The invention further relates to a method for edge-side joining of blanks from flat material to a predetermined three-dimensional hollow body with the following steps:

• a) defining a pair of points to be joined together of the edges of two flat blanks;
• b) determining the local curvature of the assumed assumed edges of the two blanks adopted as joined to the three-dimensional hollow body at the location of the pair of points defined in step a) and the cut angle of the blanks at the location of the pair of points;
• c) for each of the two blanks, shapes of a beam approximating a section of a conical shell, the conical shells of the two beams intersecting each other at a location at the determined intersecting angle and the intersecting line identifies the detected local curvature; and
• d) placing each blank on its support so that the fixed points of its edges touch each other at the location and joining the dots together.

Preferably the steps a) to d) are repeated many times and between two repetitions the blanks forwarded until the to be joined margins Completely are connected. The routes, over the two blanks on their carriers at each repetition of steps a) to d) be, are conveniently based the presupposed descriptions of the blanks and of the three-dimensional hollow body set so that two each before advancing in Step a) as points to be connected with each other Reach the place at the same time.

Further Features and advantages of the invention will become apparent from the following Description of exemplary embodiments with reference to the attached Characters. Show it:

1 a schematic plan view of a first embodiment of a working device according to the invention;

2 a section through the same implement in the configuration of 1 , along the line II-II 1 ;

3 a plan view of the working device according to a second embodiment;

4 a perspective view of a detail of a working device according to a third embodiment;

5 a detail according to a fourth embodiment; and

6 a plan view of two blanks during the connection by means of the working device according to one of the embodiments described above.

A first embodiment of the working device according to the invention is based on a in 1 shown top view and one in 2 shown section along the line II-II of 1 explained. The implement is divided into a carrier and Füh treatment device for two blanks to be welded together 1 . 2 from a polymer film and various tools arranged on this carrier and guiding device for connecting the contacting edges of the blanks 1 and 2 and to check the quality of the connection.

First, the carrier and guide device will be explained. It is composed of two straps 3 . 4 and two hold-downs 5 . 6 for each one of the blanks 1 . 2 extending on either side of line II-II 1 are opposite. In the plan view of 1 are only the hold down 5 . 6 to see the cut of the 2 shows a hold-down 5 and that of him through a narrow gap 7 for passing the blank 1 separate carrier 3 , carrier 3 . 4 and hold down 4 . 5 are each constructed identically, from a plurality of trapezoidal segments 8a . 8b , ..., 8f , hereinafter also generally designated 8, whose long baselines each facing the line II-II and each other by ball joints 9 are connected. The 1 . 2 show three segments each 8th the carrier and downholder; However, the number of segments could also be greater or, in the simplest case, only two. At one of the segments 8th each carrier or hold-down, in the embodiment shown here in each case from that of the blanks 1 . 2 as first passed segment 8a respectively. 8d , are the ball joints 9 and held with them the long baseline of the trapezoid in relation to a not shown frame of the implement stationary. At a joint in the middle of the short baseline of the trapezoid 10 engages an actuator connected to the frame 11 on, which allows the angle under which the planes of the segment 8d the carrier 3 . 4 or of the segment 8a the hold down 5 . 6 cut on line II-II, to vary. The segments 8a . 8d thus each have a single pivoting degree of freedom.

An electronic control device, not shown, controls the actuators 11 the segments 8a . 8d of the carrier 3 and the hold-down 5 or the carrier 4 and the hold-down 6 each in the same way, so that the lying on the same side of the line II-II segments 8a . 8d always parallel to each other.

In the conveying direction of the blanks 1 . 2 following segments 8b respectively. 8d grab the joint 10 and the segment with a respective subsequent segment 8c respectively. 8f connecting joint 9 three actuators each 11 at, which are arranged according to the edges of a tetrahedron and allow to position the respective joint in three dimensions freely in space or to pivot the relevant segment in three degrees of freedom. The electronic control unit calculates drive values for these actuators 11 each based on one before given course, the gap 7 between supports and downers, and which results from a given three-dimensional shape, the one from the blanks 1 . 2 should have joined membrane.

Every segment 8th the carrier 3 . 4 and the hold-down 5 . 6 is with several roles 12 . 13 . 14 for conveying the blanks 1 . 2 equipped in the direction of line II-II. Here are the roles 12 . 13 each at a first, small distance from the long baseline of their segment 8th or line II-II and the rollers 14 arranged at a second, greater distance from it. The roles 12 . 13 . 14 the carrier segments 8d , e, f and the hold-down segments 8a , b, c are each arranged exactly opposite each other, so that they touch each other along a tangent to the respective segments tangent surface and one of the blanks 1 . 2 keep it clamped between them.

Every role 12 . 13 . 14 is by its own electric motor 15 can be driven with a speed that can be set individually by the control circuit.

The tools and inspection devices of the implement according to the invention include a hot air blower 20 above the overlap area of the blanks 1 . 2 along the line II-II at the level of the first of the blanks traversed segments 8a , left in 1 , is arranged and a highlighted by a dense hatching area 21 the overlap zone blows around there the blanks 1 . 2 melt and weld. ETFE has a plasticizing temperature of 220 ° C, allowing blanks 1 . 2 from this material in the field 21 should reach at least this temperature. The distance between the surface of the blanks and a hot air ejecting nozzle of the fan 20 is preferably no greater than two or three times the diameter of the nozzle around a sharply defined weld area 21 at the blanks 1 . 2 to generate its position by any draft in the vicinity of the blower 20 is not significantly affected.

A corresponding, not shown hot air blower can be arranged below the transport and guide device to the same area 21 through a gap between the opposing carrier segments 8d to blow.

Melting by the or the hot air blower 20 has many as blanks 1 . 2 usable polymer films result in the film material shrinking locally. While such shrinkage across the weld generally results in negligible inaccuracies and can be tolerated, shrinkage along the weld can result in significant internal stresses of the sheeting and in the formation of undulations around the weld. To compensate for this effect, the electronic control unit drives the motors 15 the one behind the welding area 21 closely adjacent to the weld arranged rollers 13 the segments 8a . 8d at a speed higher than the rollers by the expected amount of shrinkage 12 in front of the welding area 21 are arranged closely adjacent to the weld still to be produced. This difference in speed leads to an elongation of the material of the blanks 1 . 2 along the weld to the expected extent of shrinkage, so that after welding and cooling the weld shrinkage and stretching by the rollers 12 . 13 compensate each other. Thus, a weld is obtained which is poor in internal stresses and in the vicinity of which the material of the blanks 1 . 2 flawless flat.

In the amount of the second passed segments 8b . 8d is a second hot air blower 22 arranged through a gap between the hold-down segments 8b the weld is blowing. A second blower, not shown, for blowing the weld from below may be positioned below the carrier segments 8e be arranged. Task of this fan or blower 22 is to heat or anneal the weld one more time to thereby in the material of the blanks 1 . 2 reduce remaining residual stresses after welding. The performance of the blower 22 is chosen so that it heats the weld to a maximum temperature between 180 and 220 ° C, which is well below the plasticizing temperature of the material of the blanks 1 . 2 lies.

The rolls adjacent to the weld 12 . 13 the segments 8b . 8e are each driven at the same speed; If further shrinkage is to be expected as a result of repeated heating, this can already be done when determining the speed difference between the rollers 12 . 13 the segments 8a . 8d be taken into account.

At the following segments 8c . 8f are each a spark induction tester 23 and a voltage-optical tester 24 arranged. The spark induction tester 23 includes two electrodes, one above and the other below the blanks 1 . 2 are arranged and which are acted upon by an alternating high voltage. If the weld between the blanks 1 . 2 If there are leaks or other faults, the current flow through the spark gap increases measurably as the fault passes. The ones with the spark induction tester 23 connected control unit registers a sol increase current and issue a warning to alert an operator that the weld has failed and should be subsequently repaired.

Instead of the spark induction tester 23 Advantageously, an ultrasonic testing device with an ultrasonic source and a microphone, which are each aligned with the weld can be used. Failure of the weld at which no material continuity between the two blanks 1 . 2 is formed, are detectable with such a device on the basis of their compared to a proper weld reinforced ultrasound echo.

The voltage-optical test device 24 includes a polarized light source that illuminates a portion of the weld from one side and a camera that observes the corresponding portion from the other side through a polarizer. If the polarizer is oriented crossed to the polarization plane of the light source and the weld is stress-free, the field of view of the camera is dark. Internal stresses of the weld, which is a birefringence in the transparent material of the blanks 1 . 2 induce local lead to a rotation of the polarization plane of the light when passing through the weld and thus to a brightening of the field of view of the camera or in extreme cases to form ring patterns around locations of high voltage. By using the voltage-optical tester 24 detecting the presence of such high voltage locations immediately after welding in real time can be prevented by welding the blanks together 1 . 2 membrane obtained is further used when inadmissible high voltages occur, which could sooner or later lead to failure of the membrane, wrinkling or leaking of the weld. Instead, such a membrane may be repaired or, if repair is not possible or not worthwhile, discarded. Costly rework, which would be required if the membrane fails only after installation at a destination or other reuse, is thus avoided.

3 shows a second embodiment of a working device according to the invention. Parts of this implement, the parts of the embodiment of 1 and 2 are denoted by the same reference numerals and will not be explained again.

The difference between the design of the 3 and those of 1 and 2 lies in the movable suspension of the segments 8a to 8f , While in the design of the 1 and 2 each joints 10 are provided in the vicinity of the short baseline of the trapezoidal segments, to which actuators 11 attack in order to adjust the intersection angle between the opposite sides of the line II-II or the weld opposite segments, is in the embodiment of the 3 For the same purpose, a gear mechanism is provided, which hereinafter referred to the hold-down shown in the figure 5 respectively. 6 is described, but symmetrically also on the carriers 3 . 4 is realized.

An electric motor 30 is at the middle segment 8b the hold-down 5 . 6 arranged and drives a bevel gear 31 that with two opposite bevel gears 32 combs. These bevel gears each sit at the end of a cylindrical rod 33 in a holder 34 rotatable, but is held axially immovable. The pole 33 is each about a universal joint 35 with a threaded rod 36 connected, each in an internal thread 37 is held, that with the adjacent segment 8a respectively. 8c connected by a ball joint. The sense of rotation of the threads of the two threaded rods 36 is in each case opposite, so that by a rotation of the electric motor 30 either the corners of the trapezoidal segments facing away from the line II-II are pulled towards one another or pushed away from one another.

An alternative embodiment of a carrier or blank holder is shown in a perspective detail view in FIG 4 shown. The several inherently rigid segments of the previously described embodiments are here by a one-piece comb 40 made of a rigid plastic material with a continuous, the weld seam facing back 41 and a variety of from the back 42 protruding teeth 42 replaced. This design allows, with a minimum number of actuators, the shape of a cone-shaped skirt by turning the spine 41 about its longitudinal axis A and bending about two axes orthogonal to the longitudinal axis with a substantially only by the density of the teeth 42 to reproduce limited accuracy.

A similar exact replica of the cone shape is with the help of a segment 50 , as in 5 shown, feasible. The segment 50 has essentially the form of a flat, rigid rod made of a rigid material, of which at the end of a narrow side two flaps forming a yoke 51 protrude. From the corresponding end of the opposite narrow side stands, over a piece of spring steel 52 one to the longitudinal direction of the segment 50 parallel axis connected bendable, a condyle 53 dimensioned to be in the yoke of an identical segment, not shown 50 to be included. The away from the joints ends of adjacent segments 50 are each by train compression springs 54 connected. By connecting a variety of segments 50 Together, a carrier or downholder in the form of a comb similar to that of 4 obtained, with the train compression springs 54 and the spring steel plates 52 a flexibility of the obtained comb shape about the two mutually perpendicular axes and the intermeshing yokes, the transmission of a parallel to the longitudinal direction A of the back torque vector of a segment 50 to the next.

6 illustrates the use of the work device according to the invention for joining blanks 1 . 2 with non-rectilinear edges. Such non-linear edges are required when a three-dimensional hollow body is to be assembled from a plurality of blanks made of flat material. In practice, the shape of the three-dimensional hollow body to be realized is generally predetermined, and the edge profiles of blanks are calculated with which the predetermined shape can be joined together.

Each continuous boundary can locally be approximated as a circular arc whose radius of curvature can vary along the edge. For the sake of simplicity, in 6 two blanks 1 and 2 shown where the radius of curvature of their edges 61 . 62 is constant in the area shown in FIG. The passage direction of the blanks 1 . 2 through the welding area 21 in 6 is from top to bottom; those above the welding area 21 lying, still unconnected portions of the edges 61 . 62 are shown as solid lines; they do not overlap. The original shape of the edges in the plane below the weld area 21 is shown by a dot-dash line; the one with the other 63 Connected edges run outside the plane of the figure. The blanks 1 . 2 driving roles 13 . 14 are drawn for simplicity on a line that the centers of curvature M1, M2 of the two blanks 1 . 2 combines. The electronic control unit knows the radius of curvature r1, r2 of the segments 1 . 2 and the distances d13, d14 of the rollers 13 . 14 from the center of the welding area 21 , It controls the speed of the motors of the rollers 13 . 14 so that for the role 13 on the part of the blank 1 a conveying speed v13 = v (1-d13 / rl) and for the roller d14 a speed v14 = v (1-d14 / r1) and correspondingly on the side of the blank 2 for the role 13 a speed v13 = v (1-d13 / r2) and for the role 14 a speed v14 = v (1-d14 / r2) results, where v is for all roles 13 . 14 same and the speed is with which the edges 61 . 62 go through the welding area. This choice of conveyor speeds ensures that both blanks 1 . 2 the center of curvature M1, M2 is always at rest, so that the edges to be joined 61 . 62 during the conveying and welding of the blanks 1 . 2 at any time in the welding area 21 meet.

At the same time, the control unit takes the form of the carriers 3 . 4 and hold down 5 . 6 with the help of the actuators 11 adapts to the predetermined, to be realized by the welding of the edges shape, it is achieved that the welded together parts of the blanks 1 . 2 are supported and guided over a large area, so not from the weight of the blanks 1 . 2 Uncontrollable tensile forces that could affect the accuracy of the promotion and the weld.

The invention is described above solely by means of a welding apparatus as an embodiment, but it is understood that instead of welding any other connection technique such as sewing, gluing, depending on the nature and suitability of the blanks 1 . 2 used material could be used. In addition, a simplified embodiment of the implement according to the invention is readily conceivable in which no roles 12 . 13 . 14 for automatically conveying the blanks 1 . 2 are present but the blanks 1 . 2 be placed by hand on a carrier or inserted between the carrier and hold-down, which are each shaped to match the three-dimensional shape to be produced so that the blanks 1 . 2 are supported by the carriers at large and at the same time touch or overlap their edges to be joined in the supported area, and then a welding head or other tool for connecting the edges of the blanks is guided along the contacting or overlapping edges of the blanks.

Claims (24)

Apparatus for edge-side joining of blanks of flat material, with two supports extending on either side of a borderline ( 3 . 4 ) for supporting a blank ( 1 . 2 ) and at least one working head ( 20 ) for connecting the carriers ( 3 . 4 ) supported blanks ( 1 . 2 ) in at least one location of the borderline, characterized in that the beams ( 3 . 4 ) each of a plurality of pivotable segments ( 8d . 8e . 8f ), of which all but one (maximum) one ( 8d ) have at least two pivot degrees of freedom. implement according to claim 1, characterized in that the working head along the borderline is movable. Tool according to claim 1, characterized ge indicates that the carriers ( 3 . 4 ) with drive means ( 12 . 13 . 14 . 15 ) for conveying the blanks ( 1 . 2 ) are equipped along the boundary line. Tool according to claim 3, characterized in that on the supports ( 3 . 4 ) Conveyor rollers ( 12 . 13 . 14 ) are mounted in at least two different distances (d13, d14) from the boundary line, and that the Förderrol len each carrier can be driven with depending on their distance from the boundary line of different speed. Tool according to one of the preceding claims, characterized in that the segments ( 8d . 8e . 8f ) at least one of the carriers ( 3 . 4 ) are formed by mutually hingedly connected plates. implement according to claim 5, characterized in that the plates are trapezoidal. implement according to claim 6, characterized in that the long baseline the trapezoidal Plates facing the boundary line. implement according to claim 6 or 7, characterized in that the trapezoidal plates are hinged at the ends of their long baselines. Tool according to one of claims 1 to 4, characterized in that at least one of the carriers has a comb-shaped slotted plate ( 40 ) made of a flexible material, wherein the segments each through the teeth ( 42 ) of the comb shape are formed. Tool according to one of the preceding claims, characterized in that at least one of the supports ( 3 . 4 ) a hold-down ( 5 . 6 ), which consists of a plurality of pivotable segments ( 8a . 8b . 8c ) and together with the carrier ( 3 . 4 ) a guide gap ( 7 ) for a cut ( 1 . 2 ) Are defined. Working apparatus according to claim 10, as far as dependent on claim 4, characterized in that each conveyor roller ( 12 . 13 . 14 ) of the carrier ( 3 . 4 ) with an opposing conveyor roller ( 12 . 13 . 14 ) of the hold-down ( 5 . 6 ) forms a gap in which the blank ( 1 . 2 ) can be clamped. Tool according to claim 11, characterized in that the working head ( 20 ) is a welding head, in particular a hot air jet welding head. Tool according to claim 12, characterized in that a first of two rollers ( 12 ) formed gap in the conveying direction of the blank ( 1 . 2 ) in front of the site of action ( 21 ) of the welding head ( 20 ) and a second of two rollers ( 13 ) formed gap behind the site of action ( 21 ) and that the roles ( 13 ) of the second gap faster than the ( 12 ) of the first gap are driven to the blank ( 1 . 2 ) at the site of action ( 21 ) to stretch. Working apparatus according to claim 12 or 13, as far as dependent on claim 4, characterized in that in the conveying direction behind the site of action ( 21 ) An annealing zone is provided. Working apparatus according to claim 12 or 13, as far as dependent on claim 4, or claim 14, characterized in that in the conveying direction behind the site of action ( 21 ) a spark discharge path ( 23 ) is provided. Working apparatus according to claim 12 or 13, as far as dependent on claim 4, or claim 14 or 15, characterized in that in the conveying direction behind the site of action ( 21 ) An ultrasonic testing device is provided. Working apparatus according to claim 12 or 13, as far as dependent on claim 4, or one of claims 14 to 16, characterized in that in the conveying direction behind the site of action ( 21 ) a material tension test device ( 24 ) is provided. Tool according to one of the preceding claims, characterized by a plurality of actuators ( 11 ) for pivoting the segments ( 8a . 8b . 8c , ..., 8f ). Working apparatus according to claim 18, as far as dependent on claim 4, characterized in that the control unit is adapted to continuously adjust the position of the segments during conveying in such a way that the edges ( 61 . 62 ) at least in the vicinity of the site of action ( 21 ) of the welding head ( 20 ) touch each other. Working apparatus according to claim 18, as far as dependent on claim 4, or according to claim 16, characterized in that the control unit is set up, the speed of the conveyor rollers ( 12 . 13 . 14 ) of each carrier ( 3 . 4 ) so that when r is the radius of curvature of the edge ( 61 . 62 ) of this carrier ( 5 . 6 ) supported cut ( 1 . 2 ) at the site of action ( 21 ) of the working head ( 20 ) and d is the distance of a conveyor roller ( 13 . 14 ) from the boundary line, the speed of the conveyor rollers ( 13 . 14 ) of this carrier ( 3 . 4 ) is proportional to rd. Method for marginal joining of blanks ( 1 . 2 ) of flat material to a predetermined three-dimensional hollow body, comprising the steps: a) defining a pair of points to be joined of the edges of two flat blanks based on a description of the blanks and the three-dimensional hollow body; b) Determining the local curvature of the edges assumed to be connected to one another of the two blanks assumed to be joined together to form the three-dimensional hollow body ( 1 . 2 ) at the location of the pair of points and the cutting angle of the blanks ( 1 . 2 ) at the location of the pair of points; c) for each of the two blanks ( 1 . 2 ) Shapes of a carrier ( 3 . 4 ), which approximates a section of a cone sheath, wherein the cone shells of the two supports ( 3 . 4 ) each other in one place ( 21 ) intersect with the determined intersection angle and the intersecting line has the determined local curvature; d) placing each blank ( 1 . 2 ) on its carrier ( 3 . 4 ), so that the fixed points of their edges at each other in the place ( 21 ) and connect the dots with each other. Method according to claim 21, characterized in that the blanks ( 1 . 2 ) on its carrier ( 3 . 4 ) and steps a) to d) are repeated until the edges to be joined ( 61 . 62 ) are completely connected. A method according to claim 22, characterized in that the routes over which the blanks are carried on their carriers are set so that two points previously defined in step a) as being to be joined together at the same time (Fig. 21 ) to reach. Method according to claim 21 or 22, characterized in that the edges ( 61 . 62 ) are connected without interruption.