EP0394531B1 - Seaming machine - Google Patents

Abstract

The invention relates to a method for producing a folded seam connection of the joint between two sheet-metal part-shells provided with seaming flanges and forming a workpiece, in particular for producing shell-type silencers (50, 50'), at least one seaming tool and the workpiece, with seaming flanges pressed against one another, being moved relative to one another. The new method is characterised in that - the workpiece is rotated about a workpiece axis of rotation extending through the workpiece essentially perpendicularly to the joint plane, - the folded seam connection is produced by using at least one seaming roller (42, 42') to roll over the seaming flanges one or more times and - the seaming roller (42, 42') is swivelled in the joint plane relative to the workpiece (50-50') or pressed against the said workpiece. The invention furthermore relates to a seaming machine. In the new method and the new seaming machine, there is the possibility of passing over interruptions in the folded seam connection in a simple manner, and for this purpose guidance of the seaming roller is provided by a correspondingly designed guide surface. <IMAGE>

Description

The invention relates to a method for producing a fold connection according to the preamble of patent claim 1. The invention further relates to a folding machine according to the preamble of patent claim 3.

A method with the features of the preamble of claim 1 and a folding machine with the features of the preamble of claim 3 are known from EP-A-0 100 687. In the folding machine described here, the folding roller carried by a swivel arm is pressed onto the folding flanges by means of a cam disc driven synchronously with the workpiece. The counter surface for the folding roller is formed on the workpiece holder. The radial feeding of the folding roller to the workpiece, which becomes necessary as the folding process progresses, takes place here by means of a complicated arrangement of a plurality of rollers and a wedge-shaped intermediate piece which can be displaced in the longitudinal direction between them.

A disadvantage of this known prior art is that changes in the course of the fold to be produced due to different shapes of the workpieces to be machined require a great deal of effort when converting the machine, because in addition to the workpiece receptacles, the cams are also exchanged, and for this in an appropriate number and design must be kept available. In addition, fluctuations in the material thickness of the workpieces to be machined can hardly be taken into account and compensated for, because the folding rollers in the known folding machine are only controlled in their position and not in their pressing force on the workpiece. In addition, the mechanical effort for the synchronous drive of the workpiece holders and the cams up.

It is therefore the task of specifying a method for producing a fold connection as well as a folding machine which deliver increased working speed and quality and which are versatile.

This object is achieved according to the invention by a method or a folding machine of the type mentioned at the outset with the characterizing features of patent claim 1 and of patent claim 3.

The new method and the new folding machine offer the advantage that the shape of the workpiece and thus the course of the fold can vary within wide limits. The new method and the new folding machine can thus be used in a variety of ways and also allow the production of fold connections which run in a complicated manner, the folding roller being guided by separate guide means. It is provided with respect to the guide of the folding roller that it is guided relative to the workpiece essentially in its radial direction by a guide roller running on a guide surface rotating with the workpiece. In terms of the device, the invention accordingly provides that a guide roller is mounted on the free end of the folding arm offset from the folding roller, at least in its axial direction, which is also rotatable about an axis running parallel to the axis of rotation of the workpiece and which during the folding process on the guide surface or curve runs, which is formed as part of one of the workpiece holders. This creates a guide for the folding roller in a simple manner, which together with the generation of the pressing force of the folding roller on the folding flanges by the piston-cylinder unit, the folding process regardless of the properties and dimensional and shape variations of the folding flanges who makes workpieces.

For example, it is possible to machine non-circular, non-rotationally symmetrical workpieces without any problems, since the folding roller is able to execute a movement following the contour of the fold. Concave radii can even appear on the workpiece as long as their radius remains larger than the radius of the folding roller. The fold also does not have to lie in the plane of the greatest extent of the workpiece, since the fold roller on a fold arm can be moved laterally from the outside to the workpiece and itself requires very little space. For the machining of workpieces in which the fold lies in one plane, it is sufficient to make the fold roller or the fold arm of the folding machine pivotable only in the parting plane. If the folding arm or the folding roller or the workpiece receptacles are designed with a further direction of freedom of movement, even folds which are not in one plane can be produced.

In a further embodiment of the invention, the method and the folding machine offer the possibility of regions of the workpiece in which the fold is interrupted by appropriate training, e.g. Elevation, easy to drive over the guide surface and then continue the folding process without any other control measures being required. In the same way, in the case of workpiece parts projecting outward from the workpiece in the fold area, e.g. Pipe connection piece, an increase in the guide surface can be provided.

Further advantageous refinements and developments of the folding machine emerge from subclaims 4 to 11.

Figur 1

eine Falzmaschine in einer ersten Ausführung mit einem Falzarm in Seitenansicht,

Figur 2

die Falzmaschine in einer zweiten Ausführung mit zwei Falzarmen in Aufsicht, teils im Horizontalschnitt,

Figur 3a

ein in der Falzmaschine zu bearbeitendes Werkstück in Aufsicht.

Figur 3b

das Werkstück aus Figur 3a im Teil-Querschnitt entlang der Linie III - III in Figur 3a,

Figur 4a und 4b

eine erste Arbeitsweise der Falzmaschine anhand zweier Arbeitsschritte, in einer Darstellung entsprechend Figur 3 b, und

Figur 5a bis 5c

eine zweite Arbeitsweise der Falzmaschine anhand dreier Arbeitsschritte, ebenfalls jeweils in einer Darstellung entsprechend Figur 3a.

Embodiments of the invention are explained below with reference to a drawing. The figures of the drawing demonstrate:

Figure 1

a folding machine in a first embodiment with a folding arm in side view,

Figure 2

the folding machine in a second embodiment with two folding arms in supervision, partly in horizontal section,

Figure 3a

a workpiece to be processed in the folding machine under supervision.

Figure 3b

3a in partial cross-section along the line III - III in Figure 3a,

Figure 4a and 4b

a first mode of operation of the folding machine based on two steps, in a representation corresponding to Figure 3 b, and

Figure 5a to 5c

a second mode of operation of the folding machine based on three work steps, each in a representation corresponding to Figure 3a.

As FIG. 1 of the drawing shows, the first exemplary embodiment of the folding machine 1 shown here has a machine base 10 in which a drive and transmission unit 11 is accommodated. A total of four parallel guide columns 12, 13, 14 and 15 extend upward from the machine base 10. At their upper end, the guide columns 12 to 15 are connected to one another by means of a yoke 17. Below the yoke 17, a pressure plate 16 is arranged, which can be raised and lowered along the guide columns 12 to 15, as indicated by the movement arrow 16 '. The lifting and lowering of the pressure plate 16 is accomplished by a lifting cylinder 34, which is centrally attached to the yoke 17. The associated piston rod 34 'extends from the cylinder 34 downwards to the pressure plate 16, where it is connected to it.

From the drive and gear unit 11 mentioned, a main spindle 2, which can be rotated by the latter, extends upwards. At its upper end, the main spindle 2 carries a first tool mounting flange 2 ', which here has the shape of a flat cylinder and is arranged concentrically with the main spindle 2.

Below the printing plate 16, a printing head 3 is provided, which can be raised and lowered together with the printing plate 16, but can be rotated relative to the latter. The print head 3 carries at its lower end a second tool mounting flange 3 ', which, like the first, lower tool mounting flange 2', has the shape of a flat cylinder. The print head 3 and the associated tool mounting flange 3 'are also concentric with each other and in alignment with the main spindle 2.

The lower tool holder flange 2 'and the upper tool holder flange 3' each carry a workpiece holder 20 or 30, which are designed as interchangeable tools, each adapted to a workpiece to be machined, and are preferably screwed to the tool holder flanges 2 'and 3'. The two workpiece receptacles 20 and 30 are each formed here with a bowl-shaped recess 21 and 31, each of which for the form-fitting reception of a half-shell of a workpiece to be machined, eg. B. a shell muffler formed from two half shells or partial shells, serve. In order to adapt the surface contours of the depressions 21 and 31 as simply and precisely as possible, the workpiece receptacles 20 and 30 are preferably provided on the inside with a plastic lining which consists of a pourable, low-elastic hardening plastic. The inner contour of the cup-shaped depressions 21 and 31 in the workpiece receptacles 20 and 30 can thus be produced with an exact fit by pouring the plastic in liquid form, pressing in a sample of the workpiece or the associated partial shell and allowing the plastic to harden.

The division plane of the two workpiece holders 20 and 30 coincides with the division joint or plane of the two partial shells of the workpiece to be machined.

On their mutually facing end faces, the two workpiece receptacles 20 and 30 each have a circumferential fold surface 22 and 32, which serve as pressure surfaces during the folding process.

Furthermore, in the illustrated embodiment of the folding machine 1, the lower workpiece holder 20 has a circumferential guide surface 23 below its folding surface 22, which, as will be explained later, can have different radial distances from the folding surface 22.

Furthermore, a folding arm 4 is shown in FIG. 1, which is arranged here to the left of the workpiece holders 20 and 30. The folding arm 4 is designed as a pivotable arm which is mounted in a pivot bearing 41 on the guide column 14 arranged on the left in FIG. 1. At its free end, which is on the right in FIG. 1, the folding arm 4 carries a guide roller 43 which rolls on the guide surface 23 of the workpiece holder 20 during the folding process.

A folding roller 42 is arranged above the guide roller 43 and is also set back somewhat with respect to the guide roller 43, ie offset to the left in FIG. 1. This folding roller 42 runs during the folding process with the interposition of the folding flanges of the workpiece to be folded on at least one of the two circumferential folding surfaces 22 and 32 of the workpiece holders 20 and 30. The pressing force of the folding roller 42 in the direction of the workpiece receptacles 20 and 30 required for the folding process is generated here by a pressure cylinder 44, which in turn is pivotable on the one in FIG. 1 left front guide column 12 is mounted in a bearing block 45. The pressure cylinder 44 is preferably operated in the folding machine 1 so that it exerts a constant force regardless of the position of its piston or its piston rod.

In the embodiment of the folding machine shown in FIG. 1, it only has a single folding arm 4; for practical use of the folding machine 1, however, it is expedient to equip the machine 1 with a pair of two identical folding arms 4 or even several pairs of the same folding arms 4.

Figure 2 shows an embodiment of the folding machine 1, in which it is equipped with a pair of two mutually identical folding arms 4. In order not to obscure the illustration, only the two folding arms 4 and the machine base 10 are shown in a top view and the four guide columns 12 to 15 are shown in section. The parts of the folding machine 1 that are still present below the folding arms 4, in particular the workpiece holder 20, are not specifically shown here.

As can be seen from Figure 2, each of the two folding arms 4 has a substantially rectangular L-shape with a longer L-leg 40 and a shorter L-leg 40 '. The longer L-leg 40 is formed at its outer end as a pivot bearing 41 and pivotally mounted on the associated guide column 14 or 15, as indicated by the movement arrows 41 '. The shorter L-leg 40 'carries at its free inner end a folding roller 42 or 42' and a guide roller 43. The two guide rollers 43 are the same here, while the folding rollers 42 and 42 'preferably have different profiles. The roles 42, 42 'and 43 are each rotatable about axes that run parallel to the workpiece axis of rotation 5 '.

To generate the pressing force required for the folding process, the already mentioned pressure cylinders 44 are used, which run at an acute angle to the respectively shorter L-leg 40 '. The cylinders 44 are each mounted in a pivot bearing 45 'on a respective bearing block 45, which in turn is rigidly connected to a fixed part of the folding machine 1, here the guide column 14 or 12. The piston rod of the cylinder 44 extends from the bearing block 45 inwards to the vicinity of the inner end of the shorter L-leg 40 '.

In addition, in the embodiment of the folding machine 1 shown here, an adjusting cylinder 46 is provided on each folding arm 4, which serves to adjust the folding roller 42 or 42 'in position relative to the guide roller 43. So that the position of the folding rollers 42 and 42 'for different runs of the folding process can be changed gradually to carry out the folding process step by step. There is also the possibility, with different profiling of the folding rollers 42 and 42 ', to begin the folding process with the first folding roller 42 and after a corresponding further rotation of the workpiece about the workpiece rotation axis 5', the second folding roller 42 'can be used.

As can further be seen from FIG. 2, here the two folding arms 40 are arranged offset from one another by approximately 90 ° about the workpiece axis of rotation 5 '. This arrangement has the advantage that in the case of workpieces, the fold of which forms a geometrical outline with very different semi-axes, the fold arms on the workpiece 4 generated torques are at least partially offset against each other. Furthermore, it can be seen from FIG. 2 that the folding arms 4 extend from the pivot bearing 41 in the workpiece rotation direction and are then angled inwards towards the workpiece axis of rotation 5 '. In this way, on the one hand, a small space requirement for the introduction of the folding arms 4 to the workpiece is achieved; secondly, the design of the folding arms 4 in the manner of rocker arms keeps the forces occurring during the machining of non-round, even concave folding lines of workpieces at a relatively low level.

An example of a workpiece 5 which can be processed with the folding machine 1 described above is shown in a top view in FIG. 3a. The view falls on the upper shell 50 of the workpiece 5, which has an outwardly projecting flange 51, which is interrupted in two areas by a pair of pipe connections 52. Not visible below the upper shell is the lower shell 50 'of the workpiece 5, which in turn also has a projecting flange 51' which runs parallel to the upper flange 51, but has a smaller width. Furthermore, the lower, the lower shell 50 'of the workpiece 5 fittingly receiving the lower workpiece holder 20 can be seen in partial areas of FIG. 3a, more precisely its circumferential guide surface 23. As FIG. 3a clearly shows, the guide surface 23 runs parallel in the region of the folded flanges 51 and 51' offset to these inwards. In the area of the pipe connections 52, on the other hand, the guide surface 23 is designed to be elevated, ie it projects outward beyond the outer boundary of the pipe connections 52. This ensures that the folding rollers on the folding arm are lifted off the workpiece 5 by the guide roller 43 rolling on the described guide surface 23 in the region of the pipe connections 52, that they run past the pipe connections 52 without contact. In the other areas of the workpiece 5, however, the folding process is carried out with constant rotation of the workpiece 5 about its workpiece axis of rotation 5 '.

Based on the partial section shown in Figure 3b along the line III - III in Figure 3a, the assignment of the two partial shells of the workpiece 5, namely the upper shell 50 and the lower shell 50 'to each other is clear. The upper shell 50 and lower shell 50 'lie with their mutually parallel folding flanges 51 and 51' on top of each other and are pressed firmly against each other by means of the end faces of the partially visible workpiece holders 20 and 30. Here, the upper rabbet flange 51 of the upper shell 50 has a greater width, i. H. a larger extension to the outside than the lower rebate flange 51 'of the lower shell 50'.

Below the two rabbet flanges 51 and 51 ', the circumferential rabbet surface 22 and the circumferential guide surface 23 can also be seen on the lower workpiece receptacle 20.

The method and the mode of operation of the folding machine 1 are explained below using two exemplary work processes according to FIGS. 4a and 4b and 5a to 5c:
First, regardless of the nature of the subsequent workflow, the upper and lower shells 50 and 50 'of the workpiece 5 are inserted into the two workpiece holders 20 and 30, the upper workpiece holder 30 being raised upwards by means of the lifting cylinder 34. After inserting the upper shell 50 and lower shell 50 ', the upper workpiece holder 20 is lowered by means of the lifting cylinder 34 and with a sufficiently large one Contact pressure pressed against the lower workpiece holder 20. The projecting flange 51 and 51 'of the workpiece 5 are pressed firmly against each other, so that mutual displacements are practically excluded. Subsequently, the main spindle 2 is rotated by means of the drive and gear unit 11. As a result, the two workpiece holders 20 and 30 are also rotated together with the workpiece 5 located therein. Next, the folding arm 4 or one of the folding arms 4 is pivoted up to the workpiece 5 until the folding roller 42 or 42 'is present with a sufficient pressing force on the folding flanges 51 and 51'.

In the further workflow, according to a first working example according to FIG. 4a, a pre-folding takes place, the upper folding flange 51 being folded downwards and inwards by means of the first folding roller 42. The pre-folding can be done in one or more passes, i.e. H. Revolutions of the workpiece 5 take place. The folded flange 51 'of the lower shell 50 initially remains undeformed.

According to Figure 4b, the second folding roller 42 'is then brought into contact with the folding flanges 51 and 51' in the first sequence example, whereby the final folding of the folding flanges 51 and 51 'takes place to the finished fold 53 in which the individual layers of the fold 53 are fixed lie on one another. Areas of the workpiece 5, in which the fold should be interrupted, or in which workpiece parts protrude, run over in the manner described by lifting the folding roller 42 or 42 'without deformation.

As shown in FIGS. 4a and 4b, two very differently profiled folding rollers 42 and 42 'are required in this example of the sequence, of which the first folding roller 42 can only take over the pre-folding and the second folding roller 42 only the pre-folding.

In the second sequence example according to FIGS. 5a to 5c, the folding rollers 42 and 42 'used here can each be used for two folding processes. According to FIG. 5a, the first folding roller 42 is also used to pre-fold the upper folding flange 51 downwards and inwards, the lower folding flange 51 'still remaining undeformed. In a second pass, according to FIG. 5b, the upper folded flange 51 is folded over further inwards, the lower folded flange 51 'also being folded over downwards. In a last folding pass, the folding process for producing the finished fold 53 is completed according to FIG. 5c, here either the folding roller 42 or the folding roller 42 'or both folding rollers 42 and 42' can be used synchronously.

Claims (11)

1. A method for producing a folded seam connection along the parting line between two shell-parts (50, 50') of sheet metal, particularly of shell shaped sound absorbers, which shell-parts form a workpiece (5) and are provided with seaming flanges (51, 51'), wherein at least one seaming tool (42, 42') and the workpiece (5) with the seaming flanges (51, 51') thereof pressed together are moved in relation towards each other, wherein the workpiece (5) is rotated about a workpiece axis of rotation (5') positioned substantially normal to the plane of the parting line and extending through the workpiece (5), wherein the folded seam connection is produced by rolling over the seaming flanges once ore more times with at least one seaming roller (42, 42') as a seaming tool and wherein the seaming roller (42, 42') is pivoted in the plane of the parting line in relation to the workpiece (5) and pressed thereto,
   characterized in,
   that the seaming roller (42, 42') is guided in relation to the workpiece (5) substantially in the radial direction thereof by a guiding roller (43) rolling on a guiding area (23) circulating with the workpiece (5) and that the pressing force of the seaming roller (42, 42') towards the workpiece (5) is generated by a piston/cylinder unit (44).
2. Method as claimed in claim 1, characterized in, that the relative movement of the seaming roller (42, 42') by the guiding area (23) is provided also in those areas where the seaming roller (42, 42') is not engaged with the seaming flanges (51, 51').
3. A seaming machine for producing a folded seam connection along the parting line between two shell-parts (50, 50') of sheet metal, particularly of shell-shaped sound absorbers, the shell-parts being provided with seaming flanges (51, 51'), wherein the shell-parts (50, 50') are insertable in correspondingly shell-shaped workpiece receivers (20, 30) and are positionable in their connection position by pressing together the seaming flanges (51, 51') thereof by corresponding pressure areas of the workpiece receivers (20, 30), wherein the workpiece receivers (20, 30) with the shell-parts (50, 50') forming the workpiece (5) are continuously passing along at least one seaming tool (42, 42') and are movable in relation thereto, wherein the workpiece receivers (20, 30) are rotatable about a workpiece axis of rotation (5') positioned substantially normal to the plane of the parting line, wherein the seaming tool (42, 42') is at least one seaming roller (42, 42') rotatably supported at the free end of a seaming arm (4) on an axis extending in parallel with the work piece axis of rotation (5') at the level of the seaming flanges (51, 51'), and wherein the seaming arm (4) is pivotable about an axis extending in parallel with the workpiece axis of rotation (5') out of the rotation area of the workpiece, and is subjectable to a pressing force in direction towards the workpiece receivers (20, 30), characterized in, that a guiding roller (43) is supported at the free end of the seaming arm (4) offset in relation to the seaming roller (42, 42') at least in axial direction thereto, with the guiding roller also rotatable about an axis extending in parallel with the workpiece axis of rotation (5') and running on a guiding area or guiding curve (23) during the seaming operation, the guiding area forming part of one of the workpiece receivers (20, 30); and in that at least one piston/cylinder unit (44) is provided for generating the pressure force of the seaming arm (4).
4. Seaming machine as claimed in claim 3, characterized in, that the seaming arm (4) is curved or bent in an L-shape in direction of the workpiece rotation, wherein the free end of the first L-leg (40) is supported as the movable part of a drag bearing (41) at a stationary part of the seaming machine (1), and wherein the free end of the second L-leg (40') carries a seaming roller (42, 42') and the guiding roller (43).
5. Seaming machine as claimed in claim 3 or 4, characterized in, that for generating the pressure force of the seaming arm (4) the piston/cylinder unit (44) is articulatingly connected with the one end thereof to the second L-leg (40') of the seaming arm (4) and with the other end thereof to the stationary part of the seaming machine (1), wherein the operating direction of the piston/cylinder unit (44) and the second L-leg (40') form an angle of between 0 and 30°.
6. Seaming machine as claimed in one of the claims 3 to 5, characterized in, that the seaming roller (42, 42') is adjustable by corresponding actuating means in relation to the guiding roller (43) substantially in radial direction of the workpiece.
7. Seaming machine as claimed in one of the claims 3 to 6, characterized in, that the seaming roller (42, 42') is passively shiftable or actively displaceable by actuating means in direction of the axis thereof.
8. Seaming machine as claimed in one of the claims 3 to 7, characterized in, that it comprises one pair or a plurality of pairs of respectively alike seaming arms (4), wherein the seaming arms (4) of a pair are arranged in a plane normal to the workpiece axis of rotation (5') offset by about 90° thereto.
9. Seaming machine as claimed in one of the claims 3 to 8, characterized in, that the two seaming arms (4) of a seaming arm pair are provided with two seaming rollers (42, 42') having a different profile.
10. Seaming machine as claimed in one of the claims 3 to 9, characterized in, that the workpiece receivers (20, 30) in the area of the shell-shaped indentation (21, 31) thereof are covered with a layer of castable plastic material curable with small resiliency.
11. Seaming machine as claimed in one of the claims 2 to 10, characterized in, that it comprises a stationary machine base (10) with a driving unit (11), a driven main spindle (2) supporting the one workpiece receiver (20) and a pressure head (3) displaceably guided at guide pillars (12, 13, 14, 15), wherein the pressure head rotatably supports the other workpiece receiver (30) and wherein the seaming arms (4) and the piston/cylinder unit (44) are supported at the guide pillars (12, 13, 14, 15) for generating the pressure force of the seaming arms (4).

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