EP1554066B1 - Device for free three-dimensional profile forming - Google Patents

Abstract

The appliance has a profile advance unit (3), a guide element (1) engaging on the profile, and a bending sleeve (5) in a retainer element (4). The profile (7) is turned in or with the guide element, and in/with the bending sleeve, about a longitudinal axis (L). The bending sleeve is born pivoted via the retainer element about a first hinge point of a rocker arm, which in turn is pivoted about a second hinge point. The retainer element is held in a guide groove, so that the inner surface of the sleeve acting in a bending manner on the outside of the profile, is permanently tangential to an arc of a circle corresponding to the desired bending radius, when the position of the retainer element in the groove changes.

Description

The invention relates to a device for 3D free-form bending of profiles with constant outer dimensions over their length, in particular with a circular shape, according to the preamble of claim 1.

Such 3D free-form bending devices are known from the prior art (see, for example, JP-A-04 127 919). From JP 08 257 643 A, a 3D profile bending device is known, in which a profile is pushed by means of a feed device by a stationary guide element and a downstream in the feed direction, integrated into a support element bending sleeve. The carrier element is rotatable about a perpendicular to the longitudinal axis of the profile to be bent through the middle of the bending sleeve extending first axis in a Recording frame held. The receiving frame itself is rotatably mounted about a second axis of rotation, which extends both perpendicular to the profile axis and perpendicular to the first axis through the center of the bending sleeve. Furthermore, the receiving frame is displaceable along both axes. Due to the coordinated rotation and displacement of the receiving frame or twisting of the carrier element in the receiving frame, the profile can be bent three-dimensionally.

A disadvantage of this bending device is that the different rotational and sliding movements of carrier element and receiving frame are to be matched exactly to each other to produce the desired profile shape. This requires on the one hand high investment costs and on the other hand a complex CNC control of the bending device.

Another bending device which operates on the same principle as the aforementioned device is known from EP 0 928 646 A1. In addition to the pivotal or displaceable about or along the perpendicular to the profile axis arranged, mutually orthogonal axes can be rotated in this device, the support member about the longitudinal axis of the profile to achieve a desired torsion of the profile during bending. In this device, although all degrees of freedom of the bending process are detected, but in addition to the feed device a total of five individual coordinated rotary or linear drives are required. This places the highest demands on the precision and the Synchronism of the drives and can not be realized inexpensively.

EP 0 928 645 A1 describes a bending device for 3D free-form bending of profiles with a simplified construction. As with the prior art described above, in this device, the profile is pushed over a feed device by a rotationally fixed guide element and a U-shaped, open bending sleeve arranged behind it. The guide element is inserted into a rotatably connected to the machine frame sleeve around which in turn an outer sleeve is rotatably mounted. In this case, the axis of rotation of the outer sleeve coincides with the longitudinal axis of the profile. The outer sleeve has a cantilever extending in the feed direction, at the end of which a supporting element carrying the bending sleeve is mounted pivotably about an axis perpendicular to the feed device and laterally offset therefrom. The position of this axis relative to the bending sleeve is chosen so that the adjustment of the desired bending radius required rotation and displacement of the bending sleeve is accomplished by a single pivoting movement. A three-dimensional bending of the profile is achieved in that the outer sleeve and connected to it via the support member and the boom with the outer sleeve, open bending sleeve by a certain angle corresponding to the desired change in the position of the bending plane, rotated about the profile axis becomes. Then, the bending sleeve is again pivoted to adjust the desired bending radius and the bend continues in a new bending plane.

Compared to the other bending devices described above, this device is characterized by a greatly simplified structure, which requires only two further drives in addition to the feed device. However, a disadvantage is the complex mechanism for rotating the bending sleeve on the rotatably mounted outer sleeve. This is contrary to a compact design of the device. Also arises in the conversion phase of the one bend in the other bend a frequently unwanted extended straight transition section. Furthermore, the use remains limited to profiles with a circular cross-section, since the profile must be kept axially rotatable in the bending sleeve.

From practice, a 3D bending device for bending profiles with a circular cross-sectional shape is also known, in which the profile is pushed by a profiledly enclosing the profile rotatable guide sleeve and an arranged behind it held in a support member, the profile also enclosing form-fitting bending sleeve. The rotation and displacement of the bending sleeve required for setting the desired bending radius is achieved in that the bending sleeve is held rotatably via the carrier element perpendicular to the feed direction in a rocker and is pivoted via a cantilever arm by means of an actuating cylinder. For the purpose of changing the bending plane, in contrast to the aforementioned prior art, instead of pivoting the bending sleeve about the profile longitudinal axis, the profile is converted by a drive integrated in the feed device its longitudinal axis is twisted. As a result, thus the relative movement between the bending sleeve and the profile to be bent runs unchanged.

As a result, based on the above-described prior art, a more compact construction of the bending device is possible. However, this device is not suitable for bending a profile with a deviating from the circular shape cross-sectional shape, since the profile must be rotatably mounted both in the guide sleeve and in the bending sleeve.

In addition, from the state of the art, the drawing bending machines for hollow profiles which are meanwhile very widespread in the automotive industry are known, with which, however, only bends in one plane, ie 2D bends, can be realized. DE 100 20 727 C1 describes a drawing bending machine for thin-walled metal pipes. Here, the tube is clamped at its front end in a jig between clamping jaws. In the case of thin-walled tubes, it is necessary to support the tube from its inside in the region of the clamping by a clamping head and in the region of the bending deformation by a bending mandrel. In order to initiate the bending of the clamped tube, a bending table, which has a circular shape in the region of the bend, which defines the achievable bending radius, is pivoted about its axis of rotation. The tube is pulled forward and simultaneously bent over the bending table. In addition to being limited to bends in a plane, the central drawback of such pull bending machines is that With them you can not realize variable radii and bends around the profile longitudinal axis.

The invention is therefore an object of the invention to provide a device that allows the 3D free-form bending of profiles with constant over its length outer shape, such as a circle, but also that of an oval or regular polygon, etc., with a simple structure.

• c) die Biegehülse über das Trägerelement um einen ersten Gelenkpunkt einer Schwinge außermittig schwenkbar gelagert ist, wobei die Schwinge ihrerseits um einen auf derselben Profilseite wie der erste Gelenkpunkt außermittig zur Profillängsachse angeordneten zweiten Gelenkpunkt schwenkbar gelagert ist,
• d) das Trägerelement auf der den Gelenkpunkten gegenüber liegenden Profilseite in einer Führungsnut gehalten ist, derart, daß der auf die Außenseite des Profils biegend einwirkende Bereich der Innenfläche der Biegehülse bei Veränderung der Position des in der Führungsnut gelagerten Teils des Trägerelements abzüglich der Rückfederung des Profils stets tangential zu einem dem jeweils gewünschten Biegeradius entsprechenden Kreisbogen ausgerichtet ist.

This object is achieved in a device of the type mentioned in the present invention that

• c) the bending sleeve is mounted eccentrically pivotable about the carrier element about a first pivot point of a rocker, wherein the rocker in turn is pivotally mounted about a second hinge point arranged eccentrically to the profile longitudinal axis on the same profile side as the first pivot point,
• d) the carrier element is held on the hinge points opposite profile side in a guide groove, such that the bending on the outside of the profile acting region of the inner surface of the bending sleeve with change in the position of the bearing in the guide groove portion of the support element minus the springback of the profile always tangential to the respective desired bending radius Arc is aligned.

The 3D free-form bending of a profile with its outer length constant over its length is achieved in that the profile is rotatable about its longitudinal axis by means of the rotary drive acting on it relative to the stationary position of the bending sleeve. In the case of profiles with a cross-sectional shape deviating from the circular shape, the guide element in its receiving unit and the bending sleeve in the carrier element are axially twisted in particular by positive engagement, while in the case of a profile with a circular cross-sectional shape, the guide sleeve and the bending sleeve can also be firmly connected to their respective receptacle. As a result of the rotation of the profile, the bending plane remains unchanged even after changing the bending direction. Therefore, the structure of the device can be structurally comparatively simple in design, as the device can be designed as an extension of a 2D-Ziehbiegemaschine. The adjusting movement of the bending sleeve for adjusting the bending radius takes place in one plane and can thus be coupled, for example, with the movement of the bending table of a drawing bending machine. Consequently, important components of a conventional draw-bending machine can continue to be used. Thus, users who already have 2D bender bending machines are able to perform 3D bends of profiles by appropriate extension of their machines without having to invest in completely new machines.

Due to the eccentrically pivotable mounting of the carrier element with the bending sleeve around a hinge point of a rocker, the positioning drive for the bending sleeve can be realized while minimizing the number of moving parts cost. An installation and control of linear axes for the displacement of the support element in two spatial directions is thereby completely eliminated.

A compact construction of the device according to the invention can be realized in that the guide element is designed as a guide sleeve rotatably mounted about the longitudinal axis of the profile. It proves to be particularly advantageous if the guide sleeve is divided longitudinally. By the division of the guide sleeve, for example in two halves, it is achieved that the clearance between the profile and the guide sleeve, and thus between the profile and the bending sleeve, can be completely eliminated. This allows bending with a particularly small bending radius compared to the prior art.

Does the passage opening of the guide element has a substantially continuously changing cross-sectional shape in the feed direction, so that the guide element acts as a shaping die on the profile, can be additionally selectively changed before the bending process of the profile cross-section. For this purpose, the guide element can be provided, for example, with mold elements inserted into its passage opening. Small changes in the cross-sectional shape can be done in the cold state, while it is appropriate in the case of larger changes in shape that the Guide member has a heater for heating the profile. It is understood that the heater supports the bending process at a small selected bending radius, even with a constant cross-sectional shape.

In an advantageous embodiment of the invention it is provided that the edges of the passage opening of the guide sleeve on and / or output side are rounded. This facilitates the insertion of the profile in the bending sleeve in the preparation of the bending process.

The device according to the invention is also particularly suitable for bending hollow profiles with variable bending radii. In the case of small bending radii, the device has a bending mandrel which supports the hollow profile when bending from the inside. As a result, collapse of the hollow profile is effectively prevented, in particular during bending with a small bending radius, and wrinkling in the bent region is reduced.

The prerequisite for a uniform bending result while maintaining the set bending radius and minimizing the stresses occurring in the profile to be bent is the tangential alignment of the region of the inner surface of the bending sleeve which flexes on the outer side of the profile to a circular arc corresponding to the bending radius. If no bending mandrel is used for internal support of the profile to be bent, the bend sets depending on the cross-sectional geometry and the wall thickness of the profile relative to the enclosed cross-sectional area not only at the exit of the guide element, but already in the guide element, so that there is thus a displacement of the circular arc in the feed direction opposite direction. A further tangential orientation of the bending sleeve to the shifted circular arc is then achieved in that the profile of the guide groove is adjustable relative to the profile longitudinal axis.

In addition to the bending, a plastic torsion of the profile about its longitudinal axis can be achieved in that the bending sleeve has a rotary drive. In this case, the bending sleeve and with it the profile to be bent by means of the rotary drive is rotated about the profile longitudinal axis, while the corresponding rotation of the guide sleeve is prevented by a suitable blocking. The rotary drive can be integrated, for example, in the support element.

For the bending sleeve there are various possibilities of embodiment with regard to the adaptation of the sleeve opening to the cross section of each profile to be bent. Thus, the bending sleeve can completely enclose the profile. A particularly variable use is also possible with a U-shaped bending sleeve.

The insertion of the profile in the bending sleeve is facilitated by the fact that the edges of the bending sleeve on and / or output side are rounded as well as in the case of the guide sleeve. It must be adequately secured during insertion of the profile as well as in operation against axial thrust, which is exerted by the profile. An exactly according to the specifications corresponding bending result is also characterized supports that the inner surface of the bending sleeve in the feed direction has a linear or slightly concave curved portion. If the profile to be bent is a hollow profile with a circular outer shape, this area should be ≥ 1/5 of the profile diameter.

To further minimize the formation of wrinkles during the bending process, it is expedient if, between the guide element and the bending sleeve coaxial with the guide element, a shaped element with a matching passage opening, which partially corresponds to the cross section of the profile, is arranged such that it acts as a fold smoother on the profile. This element, which supplements the use of the above-mentioned bending mandrel in the case of bending of hollow profiles, thus allows a further reduction of the bending radius. It can be made flexible or rigid depending on the application. In the case of a profile with an outer circular shape, it makes sense to have a ring shape. According to a particularly advantageous embodiment of the invention, it may be formed as an extension of the guide element in the direction of the bending sleeve. Likewise, an extension of the bending sleeve in the direction of the guide element is possible. In these cases, a U-shaped design of the mold element is appropriate, so that the side edges of the profile are supported during the bending process. In the case of the embodiment as a flexible mold element, it may be formed as a spiral spring or made of a rubber-elastic material, for example an elastomeric plastic.

Fig. 1

eine Vorrichtung zum 3D-Freiformbiegen von Profilen mit einem eingesetzten Hohlprofil unmittelbar vor Biegebeginn in Seitenansicht,

Fig. 2

die Vorrichtung der Fig. 1 im Längsschnitt,

Fig. 3

die Vorrichtung der Fig. 1 in perspektivischer Ansicht und

Fig. 4

die Vorrichtung der Fig. 1 im Querschnitt I-I der Fig. 2 ausschnittweise.

In the following the invention will be explained in more detail with reference to a drawing illustrating an embodiment. In detail show:

Fig. 1

a device for 3D free-form bending of profiles with an inserted hollow profile immediately before beginning of bending in side view,

Fig. 2

the device of Fig. 1 in longitudinal section,

Fig. 3

the device of Fig. 1 in a perspective view and

Fig. 4

the device of Fig. 1 in cross-section II of Fig. 2 fragmentary.

The bending device has a guide element 1 designed as a guide sleeve, which is rotatably mounted in a stationary receiving block 2 via two bearings 2a about its longitudinal axis L. This rotation can be prevented by a blocking device, not shown. Furthermore, the guide element 1 is divided longitudinally into two half-sleeves 1a, 1b. These together form a shape adapted to the profile of the passage opening 1c with the input side rounded edge 1d. In the feed direction V of a profile 7 to be bent with a longitudinal axis L, in particular a hollow profile, behind the sleeve halves 1a, 1b there is also a sleeve-shaped molded element 1e consisting of a rubber-elastic material (see Fig. 2) also adapted to the cross-sectional shape of the profile 7 and fixedly connected to the lower sleeve half 1b. Furthermore, the bending device has a feed device 3 designed as a profile collet for clamping the profile 7 on its front end 7a in the feed direction V. The feed device 3 in turn is displaceable by a linear drive, not shown, in a feed direction V. Furthermore, the feed device 3 is provided with a rotary drive, also not shown, which allows a rotation of the feed device 3 and with it the profile 7 about its longitudinal axis L.

A carrier element 4 embodied as a carrier plate is arranged behind the guide element 1 and the shaped element 1e in the feed direction V and is connected to the stationary receiving block 2 via two parallel rockers 4a (see FIG. In this case, both the carrier element 4 in the rocker arms 4a and the wings 4a themselves are rotatably mounted in the receiving block 2. The support member 4 and the wings 4a thus together form a coupling mechanism. A round opening 4b is formed in the carrier element 4, in which an inserted bending sleeve 5 is rotatably mounted by means of a bearing 4c (see FIG. In addition, the bending sleeve 5 is mounted eccentrically pivotably about the carrier element 4 about two arranged on an axis perpendicular to the profile longitudinal axis L axis first pivot points P _{1 of} the rockers 4a. The rockers 4a in turn are each pivotally mounted about one on the same profile page off-center to the profile longitudinal axis L arranged second pivot point P ₂ . In the support element 4th an unillustrated rotary drive for rotating the bending sleeve is integrated. The inner cross-section 5a of the bending sleeve 5 is also adapted to the shape of the profile to be bent 7, in particular square or circular, but sized larger than the passage opening 1c of the guide element 1. The edges 5b of the passage opening of the bending sleeve 5 are rounded for easier handling on the output side , In addition, the inner surface of the bending sleeve 5 in the feed direction V has a linear region 5c (see Fig. 4).

On the receiving block 2, a fork-shaped arm 2b is fixed, in the two branches 2c each have a curved guide groove 2d is formed. In the guide grooves 2d of the boom 2b, the support member 4 is slidably mounted on outwardly facing guide pin 4c. Furthermore, an adjusting arm 4d guided around the extended axis of rotation 6a of a disc-shaped bending table 6 is rigidly connected to the carrier element 4. The bending table 6 can be part of a conventional drawing bending device. At the end of the actuator arm 4d two outwardly facing guide pin 4e are also arranged. These engage in guide grooves 6c, which are formed in two parallel aligned extension arms 6b. The extension arms 6b are connected at one end fixed to the axis of rotation 6a of the bending table 6 and thus adjustable together with the bending table 6 via its rotary drive, not shown.

The operation of the bending device according to the invention is the following:

The hollow profile 7 to be bent is firmly clamped with its one end 7 a in the feed device 3. In the hollow section 7, a bending mandrel 8 is inserted, which is guided by the feed device 3 and is secured behind it by means of a stationary fastening element, not shown. This consists of a flexible front mandrel part 8a, in particular a ball chain for a tube having a circular cross-sectional shape, and a rear clamping head, not shown, via which the bending mandrel 8 is held axially. The bending mandrel 8 serves to prevent the collapse or excessive wrinkling of the profile 7 in the course of the bending process. Therefore, his mandrel part 8a is supported on the inside of the hollow section 7. It is understood that in a hollow profile with an angular shape, e.g. a tube with a square cross-sectional shape, the mandrel part must have a corresponding cross-sectional shape.

In preparation for the bending, the hollow profile 7 is inserted into the guide element 1 by the linear drive of the feed element 3 engaging the hollow profile 7 at its rear end 7a. This is facilitated by the input side rounded edge 1d of the passage opening 1c of the guide element 1. Due to the appropriately selected inner cross-sectional shape of the passage opening 1c, the guide element 1 is positively against the hollow section 7. Before the initiation of bending, the carrier element 4 is in one Starting position I, in which the bending sleeve 5 is arranged in alignment with the guide element 1. The hollow section 7 is now so far pushed by the guide element 1 and the mold element 1e that its remote from the feed device 3 end 7b, at the height of the mandrel part 8a of the inserted bending mandrel 8 is slightly beyond the bending sleeve 5 protrudes.

To initiate the bending in a first plane (2D bending) are at constant feed of the hollow section 7 and axially held bending mandrel 8, the boom arms 6b together with the bending table 6 by an angle α clockwise rotated. In this case, the carrier element 4 is moved via its actuating arm 4d, wherein the guide pins 4e in the guide grooves 6c assigned to them move radially outward. The support member 4 performs relative to the feed direction V of the hollow section 7 a pivoting movement, which is composed of a tilting movement and a translational movement with at least a portion perpendicular to the profile axis L. If the pivoting movement of the extension arms 6b is completed by the angle α, the carrier element 4 is in a position II which is pivoted further clockwise than in FIGS. 1 and 2, which, like any other possible position, is clearly defined by the respective position of the guide pins 4c, 4e is determined in the molded into the boom ends 2b guide grooves 2c and by the position of the support member 4 relative to the wings 4a. Each position of the support element 4 corresponds clearly a bending radius, so that by a suitable choice of Adjusting angle α the desired bending radius can be easily adjusted.

To transition to 3D free-form bending, i. a change in direction of bending or a change in the bending plane, the feed is stopped and the hollow section 7 is rotated by the associated with the profile collet 3 rotary drive to the desired angle. Both the rotatably mounted in the receiving block 2 guide element 1 and the support member 4 rotatably mounted bending sleeve 5 are rotated in the process. It can be seen that in contrast to the prior art, a strict rotational symmetry of the profile to be bent 7 in the inventive device for performing the 3D free-form bending is no longer required.

When the hollow section 7 is rotated by the feed device 3, the already bent portion of the hollow section 7 is unscrewed from the defined bending plane B of the bending device and the hollow section 7, which continues to be fed when the feed returns, is bent spatially unchanged in the bending plane B. In this case, the profile section located at the level of the bending sleeve 5 during the rotation of the hollow section 7 is also moved out of the bending plane B. This is possible without adjustment of the bending sleeve 5, since the dimensioned to the outer dimensions of the profile 7 with lateral clearance passage opening 5a of the bending sleeve 5 the profile 7 provides enough space.

If a torsion of a profile superimposed on the bend with a cross-sectional shape deviating from the circular shape is required, the guide element 1 is blocked by the blocking device and the bending sleeve 5 is rotated in a defined manner. In this case, however, no change in the bending plane can take place.

If, in addition, the bending radius is to be changed, an adjustment of the position of the bending sleeve 5 holding carrier element 4 by rotating the boom arms 6b together with the bending table 6 is carried out in the manner described.

Claims (18)

1. Device for free three-dimensional forming of profiles (7) with constant external dimensions over the length thereof, in particular with a circular shape, with an advance unit (3) for moving the profile (7) with a longitudinal axis (L), which has a rotary drive to rotate the profile (7) about its longitudinal axis (L), in an advance direction (V) parallel to this longitudinal axis (L) by a guide element (1) which has a through-opening (1c) and rests on the surface of the profile (7), and a bending sleeve (5) which is arranged in the advance direction (V) behind the guide element (1), at least partially surrounds the profile (7) to be bent and which is held in a carrier element (4), with which it can be tilted about an axis located perpendicularly with respect to the advance direction (V) of the profile (7) and can be displaced perpendicularly to the longitudinal axis (L) and tilting axis in such a way that the bending sleeve (5) acts in a bending manner on the profile (7), wherein

   (a) the device has means for rotatable mounting of the profile (7) in or with the guide element (1) about the longitudinal axis (L),

   (b) the device has means for rotatable mounting of the profile (7) in or with the bending sleeve (5) about the longitudinal axis (L), characterised in that

   (c) the bending sleeve (5) is mounted so as to be eccentrically pivotable with respect to the profile longitudinal axis via the carrier element (4) about a first articulation point (P₁) of a rocker (4a), the rocker (4a) being pivotably mounted in turn about a second articulation point (P₂) arranged eccentrically with respect to the profile longitudinal axis (L) on the same profile side as the first articulation point (P₁),

   (d) the carrier element is held in a guide groove (2d) on the profile side located opposite the articulation points (P₁, P₂) in such a way that the region of the inner face of the bending sleeve (5) acting in a bending manner on the outside of the profile (7), on a change of the position of the part of the carrier element (4) mounted in the guide groove (2d), less the spring-back of the profile (7), is always oriented tangentially with respect to an arc of a circle corresponding to the respectively desired bending radius.
2. Device according to claim 1, characterised in that the guide element (1), which is rotatably mounted, is configured as a guide sleeve (1).
3. Device according to claim 2, characterised in that the guide sleeve (1) is longitudinally divided.
4. Device according to any one of claims 1 to 3, characterised in that the through-opening (1c) of the guide element (1) has a cross sectional shape which changes substantially continuously in the advance direction (V), so that the guide element (1) acts as a shaping matrix on the profile (7).
5. Device according to any one of claims 1 to 4, characterised in that the guide element has a heating unit to heat the profile (7).
6. Device according to any one of claims 2 to 5, characterised in that the edges (1d) of the through-opening (1c) of the guide sleeve (1) are rounded on the input and/or output side.
7. Device according to any one of claims 1 to 6, characterised in that in the case of a hollow profile (7) to be bent, the device has a bending block (8), which supports the hollow profile (7) from the inside during bending.
8. Device according to any one of claims 1 to 7, characterised in that the course of the guide groove (2d) can be adjusted relative to the profile longitudinal axis (L).
9. Device according to any one of claims 1 to 8, characterised in that the bending sleeve (5) has a rotary drive.
10. Device according to any one of claims 1 to 9, characterised in that the bending sleeve (5) is suitable to completely surround the profile (7).
11. Device according to any one of claims 1 to 9, characterised in that the bending sleeve (5) is U-shaped.
12. Device according to any one of claims 1 to 11, characterised in that the edges (5b) of the bending sleeve (5) are rounded on the input and/or output side.
13. Device according to any one of claims 1 to 12, characterised in that the inner face of the bending sleeve (5) has a linear or slightly concavely curved region (5c) in the profile longitudinal direction (L).
14. Device according to claim 13, characterised in that in the case of a hollow profile (7) with a circular cross section, the linear or slightly concavely curved region (5c) is ≥ 1/5 of the profile diameter.
15. Device according to any one of claims 1 to 14, characterised in that a shaped element (1e) with an adapted through-opening, which corresponds portion-wise to the cross section of the profile, is arranged between the guide element (1) and the bending sleeve (5) in such a way that it acts as a fold smoother on the profile (7).
16. Device according to claim 15, characterised in that the shaped element (1e) is configured as an extension of the guide element (1) in the direction of the bending sleeve (5).
17. Device according to claim 15, characterised in that the shaped element (1e) is configured as an extension of the bending sleeve (5) in the direction of the guide element (1).
18. Device according to claim 15, characterised in that the shaped element (1e) is configured as spiral springs, metal or elastomer rings.

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