EP2223752B1 - Tool construction set for creating bending tools which can be coupled to a tool unit of a bending machine for bending or coiling strand-like workpieces - Google Patents

Abstract

The set has tool receptacles (4) with mandrels (3) attached to pin elements (2). Bending elements (5) include profile jaws (6), which include profile grooves (7) for pressing strand-like workpieces during bending against the mandrels. The grooves are designed for different cross-sections of the workpieces. Each pin element and each bending element are provided with connection regions (8, 9) for connecting together with each other. The connection regions are designed such that each bending element is fastened to each pin element in a preset relative position relative to each pin element.

Description

The invention is based on a tool kit for forming bending tools that can be coupled to a tool unit of a bending machine for bending or winding strand-shaped workpieces.

On bending machines for bending or winding strand-shaped workpieces such. For example, on tube bending machines, wire bending machines, two-head bending machines or leg spring machines, a separate tool is usually used for each bending radius and for each shape of the strand-shaped workpiece to be bent (eg., For each wire diameter or pipe diameter o. If the bending radius or the shape of the strand-shaped workpiece to be machined changes, the tool previously used must be replaced by a new tool that corresponds to the new specifications.

Such one-piece tools are z. B. in the spring winding machine from the DE 3539730 C2 , in the spring manufacturing device of the DE 10134828 B4 or in the wire bending machine from the DE 19547005 C2 used. These are always conventional, one-piece winding or bending tools with bending mandrel and bending element for a given wire and a certain bending or winding diameter.

In the market, a solution has become known with a bending tool, in the tool holder a bending mandrel used and a bending element is screwed to allow in case of breakage a single exchange of mandrel and / or bending element. But here, too, the bending tools are made individually for very specific parts.

In this known prior art requires the availability of different tools for the different winding or Windedurchmesser and changing

Forms of the workpieces to be bent or wound not only a considerable capital commitment, and a relatively large space for storing the tools, also the purchase of the various tools is costly and the time required to replace the tools with changing specifications for processing the strand-shaped workpiece considerably.

Proceeding from this, the object of the invention is to avoid the disadvantages as far as possible and to create a possibility in which the availability of tools for different bending and winding diameter as well as for different forms of treated strand-shaped workpieces associated with significantly lower cost and space requirements is significantly reduced, the need for a change of the complete tool and in most cases a change in the machining specifications for the bending or winding of the strand-shaped workpiece, a significant reduction of the conversion time can be achieved.

According to the invention, this is achieved by providing a tool kit for forming bending tools for bending or winding strand-shaped workpieces that can be coupled to a tool unit of a bending machine, wherein the individual bending tool has a tool holder with a mandrel element and a concentric bending mandrel and a bending element associated therewith, and the tool kit a plurality of tool holders each having a thereto attached mandrel element and a bending mandrel attached thereto, wherein the bending mandrels of the individual mandrel elements have different diameter to each other, and further comprises a plurality of bending elements with mold jaws, each with a forming groove for pressing the strand-shaped workpiece during bending against the bending mandrel are provided, wherein the forming grooves of different mold jaws are designed for each different workpiece cross-sections, and wherein each mandrel element and each of the bending element are each provided with a connecting portion for connection to each other and the connecting portions of all the mandrel elements and all the bending elements are formed so that each bending element can be fastened to each mandrel element.

The inventively provided possibility of training a variety of tools due to the components of a tool kit treads a completely new way in the field of bending or winding tools. It is the first time created by a targeted at least two-part design of each bending tool the possibility for a composition of individual components of a kit. This initially leads to the advantage of a simpler production, since the bending elements and the mandrel (with mandrel element and tool holder) can be made independently, which also advantageously allows the use of different materials for the mandrel element and the bending element.

By providing a kit for building a variety of bending tools not only the number of items that need to be available, reduced, but also significantly reduced the space required for the storage of tools and a total of this a significant cost advantage can be achieved.

In this case, if only changes the shape of the strand-like workpiece to be machined, not to remove the entire bending tool on the bending machine and replace, but only replace the existing bending element with a new, which corresponds to the changed shape of the workpiece to be machined. This is faster than a change of the whole tool feasible and thus cheaper from this point of view.

The possibility of variation of the bending tools that can be produced with a tool kit according to the invention depends on the scope of the individual parts contained in the kit. If the kit includes tool holders with bending mandrels whose diameters cover the most important bending or winding radii, and if the assembly also contains bending elements with shaping jaws for the most important shapes of the strand-shaped workpieces to be machined, the usually required tool variations can be largely covered with such a kit ,

The fact that each bending element, when it is attached to one of the tool holders with mandrel element and mandrel, is fixed there in a predetermined mandrel element predetermined, predetermined relative position to this, can be ensured by a suitable determination of this relative position that even in a Changing the diameter of the mandrel or when changing the shape of the workpiece to be treated (and thus a change in the configuration of the mold baking of the bending element) is always given the correct distance between the mold jaws of the bending element and the outer circumference of the mandrel automatically.

Preferably, in the invention, the connecting portions of the mandrel elements are formed so that the connecting portions of all bending elements are positively coupled with those of the mandrel elements, which can also achieve a very quick assembly of the individual parts of the tool kit to the finished tool. In this case, preferably, each bending element for attachment to a mandrel element against a stop surface attached to the latter, and thereby guided in a form-fitting manner in the radial direction of the tool holder, formed and attached to this. By the formation of this abutment surface is thereby ensured the predetermined relative position between the bending element and mandrel element in the assembled end position both.

In another advantageous embodiment of the invention, the connecting portion of each mandrel element has a parallel to the center axis of the mandrel extending to the outside of the tool holder open dovetail groove and the connecting portion of each bending element a corresponding, einschiebbare in this dovetail shape, in which case the groove bottom of the dovetail groove Represents stop surface for the bending element. In this embodiment, the mandrel element is no longer for the assembly of a bending element, as in the aforementioned embodiment, a positive radial guide on the mandrel element in the direction of the stop surface out, but the positive guide is here via the dovetail groove, when the connection region of the flexure in this is introduced, so that in this case the bending element is transferred in a direction parallel to the central axis of the bending mandrel in its final assembly position on the mandrel element.

Is in a tool kit according to the invention on the mandrel element a stop surface formed against which, positively guided in the radial direction, the bending element can be applied and attached to it, it is very particularly preferably arranged in a plane parallel to the longitudinal center axis of tool holder, mandrel element and mandrel level. In this case, advantageously comprises the connecting portion of each mandrel element at the lateral end edges of the abutment surface perpendicularly extending from this to the outer shell of the mandrel element side surfaces and on the bending mandrel remote from underside of the stop surface a perpendicular to this shaped groove for positive radial insertion of the connecting portion of a bending element between the side walls and until it rests against the abutment surface, the corresponding bottom region of each bending element having a shape complementary to the shape of the shaping groove. In this embodiment of the invention, a rapid assembly of a bending element on the tool holder by lateral pushing the same against the stop surface (under positive guidance at its bottom portion) is possible.

The attachment of each bending element on a mandrel element after applying its connection region against the abutment surface of the latter takes place on this preferably by means of a screw, preferably by means of a countersunk screw, in a radial bore of the bending element. In a guide of the bending element on the mandrel element in the context of a dovetail guide, which prevents per se, a radial detachment of the inserted bending element from the mandrel element, it is no longer necessary that in the It is sufficient here completely, if in a bore of the mandrel element in the direction outwardly spring-biased locking pin sitting in the final assembly of the inserted bending element with a corresponding location on the bending element locking recess in latching, but releasable engagement occurs.

The forming grooves of the forming jaws of the bending elements can be made in a tool kit according to the invention in a variety of forms, in such a way that as many different tool shapes are coverable. However, it is recommended that in a tool kit according to the invention, the forming grooves of the forming jaws of at least a portion of the bending elements form grooves having a circular arc-shaped curved cross-section, wherein the individual forming grooves are provided with mutually different radii of curvature.

It is also advantageous if the radial distance between the stop surface and the outer circumference of the bending mandrel is the same for all tool holders.

Preferably, the bending mandrel is formed integrally with the respective tool holder and the mandrel element.

Another, likewise preferred embodiment of the invention is that in addition also the bending mandrel is formed as an independent of the mandrel element component of the kit, in which case a tool kit according to the invention comprises a plurality of bending mandrels different mandrel diameter and thereby each mandrel element with means for provided concentric fastening a bending mandrel and each bending mandrel of the kit to each mandrel element, or, at least, to certain mandrel elements, can be fastened. In such a case, however, the mold jaws of the bending mandrels are so adjustable form that they are in the mounted bending element, in the radial direction on the bending mandrel in their distance from this adjustable and can be fixed.

The invention furthermore also relates to bending tools which can be coupled to a tool unit of a bending machine for bending or winding strand-shaped workpieces, wherein these bending tools consist of the components of a tool kit according to the invention.

Fig. 1

eine Perspektivdarstellung eines erfindungsgemäßen Bausatzes mit drei Werkzeugaufnahmen, jede mit einem Dornelement und einem Biegedorn versehen, und mit drei Biegeelementen;

Fig. 2

eine Seitenansicht der drei Werkzeugaufnahmen mit Dornelement und Biegedorn sowie der drei Biegeelemente gemäß Fig. 1 (übereinander);

Fig. 3

eine Perspektivdarstellung einer Werkzeugaufnahme mit Dornelement und Biegedorn und eines Biegeelementes vor dessen Einführung in eine schwalbenschwanzförmige Führungsnut im Dornelement;

Fig. 4

eine Seitenansicht der Werkzeugaufnahme aus Fig. 3, mit bereits eingeführtem Biegeelement;

Fig. 5

eine schräge Perspektivdarstellung des Biegewerkzeuges aus Fig. 4;

Fig. 6

ein erfindungsgemäßes Biegewerkzeug, bei dem eine Werkzeugaufnahme mit einem Biegedorn kleinen Durchmessers und mit einem entsprechenden Biegeelement;

Fig. 7

eine schräge Perspektivansicht einer Biegeaufnahme mit einem Biegedorn größeren Durchmessers als Fig. 6 und einem entsprechenden Biegeelement, und

Fig. 8

eine Perspektivansicht eines Biegewerkzeuges mit einem Biegeelement, dessen Formnut keinen kreisabschnittförmigen Querschnitt aufweist.

The invention will now be explained in more detail by way of example with reference to the drawings in principle. Show it:

Fig. 1

a perspective view of a kit according to the invention with three tool holders, each provided with a mandrel member and a bending mandrel, and with three bending elements;

Fig. 2

a side view of the three tool holders with mandrel element and mandrel and the three bending elements according to Fig. 1 (Above each other);

Fig. 3

a perspective view of a tool holder with mandrel element and bending mandrel and a bending element before its introduction into a dovetail-shaped guide groove in the mandrel element;

Fig. 4

a side view of the tool holder Fig. 3 , with already introduced bending element;

Fig. 5

an oblique perspective view of the bending tool Fig. 4 ;

Fig. 6

an inventive bending tool, wherein a tool holder with a bending mandrel of small diameter and with a corresponding bending element;

Fig. 7

an oblique perspective view of a bending recording with a bending mandrel larger diameter than Fig. 6 and a corresponding bending element, and

Fig. 8

a perspective view of a bending tool with a bending element whose forming groove has no circular section-shaped cross-section.

In Fig. 1 a tool kit 1 is shown, which consists of six component elements, namely three mandrel elements 2, each of which is provided on its upper side with a centrally disposed, axially projecting mandrel 3 and each mounted on a tool holder 4.

In addition belong to the kit 1 also three bending elements 5, at the top of each one integrally a mold jaw 6 is attached.

The mandrel elements 2 are formed integrally with their respective bending mandrel 3 and the associated tool holder 4.

It is how the Fig. 1 and 2 show, the molding jaws 6 provided on each bending element 5 with a shaping groove 7, which, in the in the Fig. 1 and 2 illustrated mold jaws 6, each having a circular section-shaped cross-section. In this case, the molding groove 7 of in Fig. 1 provided on the left most bending element 5 with a relatively large groove radius, thus designed for bending a relatively thick wire. The middle bending element 5 has, as in Fig. 2 also shown in the middle illustration, on the other hand a smaller groove radius, while that in Fig. 1 shown rightmost bending element 5 (in Fig. 2 : at the top) has a shaping groove 7 with a very small bending radius.

At each tool holder 4 with the mandrel element 2, in particular extending in the region of the mandrel element 2, in each case a connecting region 8 for connecting a bending element 5 is formed.

Also, each bending element 5 has at its in the installed state the connecting portion 8 of the mandrel element 2 side facing a connecting portion 9, with which it engages with the connecting portion 8 of the mandrel element 2 during assembly into one another.

The connecting portion 8 of each mandrel element 2 is as shown Fig. 1 is very well visible, provided with a stop surface 10 which extends parallel to a tangential plane to the cylindrical surface 11 of the associated bending mandrel 3, in a radial distance A to this.

It should be noted that the distance A between the cylindrical surface 11 of the bending mandrel 3 and the stop surface 10 of the connecting portion 8 is identical in all mandrel elements 2 of the kit 1.

The orientation and the exact position of the abutment surface 10 of each connecting portion 8 of the individual mandrel elements 2 ensures that the relative position between the flexure 5, when it is attached to the stop surface 10 adjacent to the mandrel element 2, and the lateral surface 11 of the respective mandrel 3 to the different mandrel elements 2 always leads to a predetermined position with an equal distance A to the lateral surface 11 of the bending mandrel 3, regardless of which diameter of the mandrel 3 of the individual mandrel element 2 has.

Like the representation of the Fig. 1 continues to show in detail, in which respect expressly to the presentation of the Fig. 1 is substantially noted, the connecting portions 8 of the mandrel elements 2 (with associated tool holder 4) continue from the (to the rotation axis M of each bending mandrel 3 parallel) side edges of the respective stop surface 10 perpendicularly running side walls 12, 13 and one on the overhead bending mandrel This consists of a flat, perpendicular to the rotation axis M of the mandrel 3 and perpendicular to the stop surface 10 extending groove bottom 15, from the outside of the respective mandrel element 2 to the lower End of the abutment surface 10 extends, and two also flat, but to him below each at an equal angle inclined or curved groove walls 15A, each of which opens at its top in one of the two side walls 12 and 13 of the connecting portion 8.

Correspondingly, the connecting region 9 of each bending element 5 on its (when installing) the stop surface 10 on a mandrel element 2 side facing also a flat contact surface 16 which comes in the assembled state of a bending element 5 on a mandrel element 2 against the stop surface 10 of the latter to rest.

In addition, each bending element 5 is provided on its lower side with a shaping of the mold groove 14 adapted shaping, namely with a lower flat surface 17 which corresponds in size to the size of the groove bottom 15 and from the side two flat inclined surfaces 18, 19 below the same Run angle upwards, under which the lateral groove walls 15A are inclined to the groove bottom 15.

In addition, all the bending elements 5 each have a same width B ( Fig. 1 ), which corresponds exactly to the distance between the two side walls 12 and 13 of each mandrel element 2.

In addition, all bending elements 5 in the direction of the mandrel 3 also have a depth T ₁ , T ₂ , T ₃ ... (see. Fig. 1 ), which is selected so that any bending element 5, which is attached to any mandrel element 2, preferably does not protrude radially beyond the outer periphery of the associated tool holder 4.

In each Biegelement 5, an opening 20 is mounted, which is assigned in a mounted on a mandrel element 2 state of the bending element 5 opening into the stop surface 10 threaded hole 21 in the mandrel element 2, so that the bending element 5 by means of a through-bolt, z. B. a countersunk screw, with the mandrel element 2 can be releasably connected.

Each bending element 5 has on its upper side a forming jaw 6, which is provided on its side facing the bending mandrel 3 with a shape which is adapted to the strand-shaped workpiece to be bent.

In the in the Fig. 1 and 2 illustrated embodiment of a kit, the mold jaws 6 of the bending elements 5 are each provided with forming grooves 7, wherein in this embodiment, these forming grooves each have a circular section-shaped cross-section.

In further embodiments, the shapes, such as the mold grooves 7, on the mold jaws 6 can also be designed with completely different or different design. So z. B. curves may be appropriate, which are adapted to the wire diameter and allow a relative movement between the mold jaw 6 and the workpiece. Such an embodiment is usually used during bending (roll-bending by means of a standing wire).

The distances C1, C2, C3 between the contact surface 16 and the molding jaws 6 of each bending element 5 are adapted to the wire diameter or to the shape of the strand-shaped workpiece to be bent.

As Fig. 8 shows, the shape of the mold jaw 6 may also be provided from different salaried flat surfaces with sharp edges 22 or even the mating surface 23 with a wedge-shaped orientation with which the mold jaw 6 "bite" into the workpiece and thus a relative movement between the workpiece and Can prevent bending element 5. Such an embodiment is usually used during winding (for example production of spring bodies) (tension bending with continuously fed wire).

In the Fig. 3 to 5 another embodiment for the connecting portion 8 of a mandrel element 2 and the connecting portion 9 of a bending element 5 is shown:

Here, a dovetail groove 24 is inserted into the mandrel member 2, the groove bottom 25 the same arrangement (orientation and position) as the stop surface 10 in the embodiment according to the Fig. 1 and 2 and also fulfills the same investment function as this. The groove bottom 25 of the dovetail groove 24 is also, as the stop surface 10, mounted away from the lateral surface 11 of the mandrel 3 at a distance A , the distance A of the embodiment of Fig. 1 and 2 equivalent.

Moreover, also to this embodiment with dovetail groove on the graphic representation of Fig. 3 to 5 expressly referred to as essential.

In accordance with the shape of the dovetail groove 24, the connecting region 9 of the bending element 5 is also formed, namely in a shape complementary to the dovetail groove 24, as likewise shown in FIGS FIGS. 3 and 5 is shown.

In this embodiment, the bending element 5 is inserted for mounting from above and axially parallel to the axis of rotation M of the bending mandrel 3 in the dovetail groove 24 (see. Fig. 3 ) and up to the abutment against an axial Einschiebestrecke delimiting stop surface 26 which is formed on the mandrel element 2, moved ( Fig. 5 ).

As Fig. 4 showing a partially sectioned side view of the finished bending tool (like this in FIG Fig. 5 is also illustrated in a perspective view), in the mandrel element 2, a groove bottom 25 perpendicular to the receiving bore 27 is mounted, in which a locking pin 28 is received, which is biased by a biasing spring 29 toward the outside of the bore 29.

In the bending element 5, a locking recess 30 is formed at a corresponding position whose position is assigned to when introduced into the dovetail groove 24 bending element 5, in which the front head portion of the locking pin 28 is pressed by the biasing spring 29 and thus the bending element 5 in his Mounting end position is releasably latched.

The 6 and 7 show, in each case in a perspective illustration, a bending tool W constructed from the individual kit elements , using the same mandrel element 2, which is once equipped with a bending element 5 for a relatively small workpiece diameter (thin wire, Fig. 6 ) and once with a bending element 5 for a relatively large workpiece diameter (thick wire, Fig. 7 ) is provided. In this case, the workpiece 35 is supplied in the direction of the arrow z and positioned between the mold jaw 6 of the bending element 5 and the lateral surface 11 of the bending mandrel 3. By rotating the tool in the direction x and by simultaneously moving it in the direction y , the workpiece 35 is wound around the lateral surface 11 (as the effective bending surface) of the bending mandrel 3.

The bending element 5 of in Fig. 6 shown tool W corresponds z. B. the in Fig. 1 shown rightmost bending element, and the mandrel element 2 in the Fig. 1 in the middle illustrated mandrel element.

The bending element 5 of the tool W from Fig. 7 in contrast corresponds to z. B. the bending element 5, the in Fig. 1 is shown in the middle.

Fig. 8 Finally shows a bending tool W, in which on the tool holder 4, a mandrel element 2 is seated with a bending mandrel 3, which is axially relatively long and thus has a large lateral surface 11 as a bending surface. The bending element 5 used here has a shaping jaw 6, which (as already described above, page 9, described) from different mutually engaged flat surfaces with sharp edges 22, wherein the mating surface 23 is provided with a wedge-shaped orientation for biting into the workpiece.

It is also possible to construct the kit 1 with its various individual elements so that in addition not even the bending mandrels 3, as shown in the described examples of the figures, are firmly attached to the mandrel element 2, but also as a separate from the mandrel elements 2 kit Parts are executed. This is z. B. possible, on one and the same mandrel element 2 a bending mandrel 3 with the same diameter, but a different axial length (and thus a different sized lateral surface 11) to attach. It is also possible here to use bending mandrels 3 of different size on a mandrel element 2 of choice, with the possibility of interchangeable bending mandrels 3, the mandrel elements 2 must be designed so that the different bending mandrels 3 can be mounted on each mandrel element 2. Accordingly, the holding and fastening means must be designed on the mandrel elements 2.

If 3 different outer diameter of the kit bending sets are used on the same mandrel element 2, it is necessary that then there are also used for use bending elements 5 are formed in the mounted state radially to the mandrel 3 and away from this adjustable mold jaws 6 so that the distance between each mold jaw 6 and the lateral surface 11 of each bending mandrel 3 used can be adjusted according to the shape of the workpiece 35 to be bent. It is also necessary to ensure that in such a kit, the contact surface 10 is formed on each mandrel element 2 so that even with the use of the bending mandrel 3, which has the largest diameter, still a distance A to the lateral surface 10 of the rotary mandrel 3 guaranteed is.

Similarly, there is also the possibility on a bending element more than a shaping jaws 6, z. B. on top of each other, for more than a wire diameter o. Ä. To install.

Claims (12)

1. A tool kit (1) for forming bending tools (W) which can be coupled to a tool unit of a bending machine for bending or coiling strand-like workpieces (35), with the individual bending tool (W) comprising a tool holder (4) with a mandrel element (2) and a bending mandrel (3) which is concentric in relation to the same, and a bending element (5) which is associated with said bending mandrel (3), and the tool kit (1) comprises several tool holders (4) with one respective mandrel element (2) and a bending mandrel (3) attached thereto, with the bending mandrels (3) of the individual mandrel elements (2) having differently large bending diameters in relation to one another, and further several bending elements (5) with profile jaws (6) which comprise a respective profile groove (7) for pressing the strand-like workpiece (35) against the bending mandrel (3) during bending, with the profile grooves (7) of different profile jaws (6) each being arranged for different workpiece cross sections, and with each mandrel element (2) and each bending element (5) being respectively provided with a connecting region (8; 9) for the connection with each other, and the connecting regions (8; 9) of all mandrel elements (2) and all bending elements (5) are arranged in such a way that each bending element (5) can be fastened to each mandrel element (2) in a predetermined relative position.
2. A tool kit according to claim 1, wherein the connecting regions (8) of the mandrel elements (2) are arranged in such a way that the connecting regions (9) of all bending elements (5) can be coupled with them in an interlocking manner.
3. A tool kit according to claim 2, wherein each bending element (5) can be placed for fastening to a mandrel element (2) against a stop surface (10) attached thereto by being guided in an interlocking fashion in the radial direction of the mandrel element (2) and can be fastened to said stop surface (10).
4. A tool kit according to claim 3, wherein at the lateral end edges of the stop surface (10) the connecting region (8) of each mandrel element (2) comprises lateral surfaces (12, 13) extending perpendicularly from the same up to the outside jacket of the mandrel element (2) and, on the bottom side of the stop surface (10) facing away from the bending mandrel (3), a profile groove (14) directed perpendicularly to the same and radially for the interlocking insertion of the connecting region (9) of a bending element (5) between the lateral surfaces (12, 13) and until contact is made with the stop surface (10), with the respective base region of each bending element (5) having a shaping which is complementary to the shape of the profile groove (14).
5. A tool kit according to one of the claims 1 to 4, wherein for the purpose of fastening to a mandrel element (2) each bending element (5) can be fastened to the mandrel element (2) by means of a screw after the contact of the connecting region (9) of said bending element with the stop surface (10) of the mandrel element (2).
6. A tool kit according to one of the claims 1 or 2, wherein the connecting region (8) of each mandrel element (2) comprises a dovetail groove (24) which extends parallel to the central axis (M) of the bending mandrel (3) and is open towards the outside of the mandrel element (2), and the connecting region (9) of each bending element (5) has a respective shaping which is complementary to the dovetail groove (24) and can be slid into the latter.
7. A tool kit according to claim 6, wherein an accommodating bore (27) for a latching pin (28) is provided in each mandrel element (2) in the region of the base (25) of the dovetail groove (24), which bore opens into the groove base (25), with the latching pin (28) being pretensioned by a spring (29) in the direction out of the base (25) of the groove, and that a latching recess (30) is formed in each bending element (25) in its connecting region (9) into which the latching pin (28) can engage in a latching manner when the bending element (5) is fully slid into the dovetail groove (24).
8. A tool kit according to one of the claims 1 to 7, wherein the profile grooves (7) of the profile jaws (6) of a least some of the bending elements (5) of the kit (1) comprise profile grooves (7) having radii of curvature which are different with respect to one another and are curved in the cross section in manner of an arc of a circle.
9. A tool kit according to one of the claims 3 to 8, wherein the radial distance (A) between the stop surface (10) and the outside circumference (11) of the bending mandrel (3) is the same size in all mandrel elements (2).
10. A tool kit according to one of the claims 1 to 9, wherein each bending mandrel (3) is arranged integrally with the associated mandrel element (2).
11. A tool kit according to one of the claims 1 to 9, comprising a plurality of bending mandrels (3) of different diameter, with each mandrel element (2) being provided with means for the concentric fastening of a bending mandrel (3) and each bending mandrel (3) of the kit (1) can be fastened to each mandrel element (2).
12. A bending die which can be coupled with a tool unit of a bending machine for bending or coiling strand-like workpieces, composed of components of a tool kit (1) according to one of the claims 1 to 10.

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