Device for bending hollow structural components

Abstract

A device (10) for bending hollow structural components (100), in particular tubes, is disclosed, comprising a mandrel shaft (40) for receiving a receiving element (20), wherein a series of at least two interconnected ball joints (30, 30') can be inserted end-to-end into the receiving element (20), wherein the series of ball joints (30, 30') can be closed off by a ball end joint (70) at an end opposite the receiving element (20), wherein each ball joint (30, 30') of the series is enclosed circumferentially by a scale (50, 50') and the ball end joint (70) by an end scale (60), and the scales (50, 60) overlap at least partially.

Description

[0001] The invention relates to a device for bending hollow structural components, in particular pipes, comprising a mandrel shaft for receiving a receiving element, wherein a series of at least two interconnected ball joints can be inserted into the receiving element at its end.

[0002] Several bending machines are already known for bending metal tubes. These machines can position a tube using a clamping unit. A bending head can then act on the tube and deform it directly or with the aid of a support die.

[0003] To ensure a consistent cross-section of the pipe, a mandrel is typically inserted into the pipe before the bending process. For example, a scale mandrel with a rope core is known, the length of which is adjusted before use to prevent the scales from rattling or jamming.

[0004] Furthermore, scale mandrels for insertion into pipes are known, designed as a chain with scale links and having a fixed length. The individual scale links are coupled to each other via hinges and can therefore only be pivoted along one direction of rotation.

[0005] Known bending mandrels are listed in VDI 3430.

[0006] The previously known scale thorns have relatively large gaps between the respective scales and the pipe to be bent, which means that a continuous maintenance of the inner cross-section of the pipe cannot be guaranteed.

[0007] FR 2 417 351 A1, on which the preamble of claim 1 is based, describes a conventional bending mandrel with a mandrel shaft and a plurality of ball joints and scales. The ball joints are connected to the scales via two-part coupling sleeves. Pivoting movement between the ball joints and the scales is not possible.

[0008] Other embodiments of conventional bending mandrels are known from CN 101 367 099 A and US 4 123 930 A.

[0009] The invention is based on the objective of creating a device, for example a support mandrel, which enables wrinkle-free bending of hollow structural components with a minimal change in cross-section.

[0010] This problem is solved by the features specified in claim 1. Further advantageous embodiments of the invention are described in the dependent claims.

[0011] According to one aspect of the invention, a device for bending hollow structural components, particularly pipes, is provided. The device can be designed, in particular, as a so-called hinged mandrel and have a mandrel shaft for receiving a receiving element. A series of at least two interconnected ball joints can be inserted into the receiving element at its end. The series of ball joints is preferably terminated by a ball end joint at an end opposite the receiving element, wherein each ball joint in the series is circumferentially enclosed by a hinge and the ball end joint by an end hinge. Advantageously, the hinges overlap at least partially.

[0012] According to the invention, the scales and the end scale have a retaining section. A ball joint or a ball end joint can be positively inserted into the retaining section and pivoted within it. Preferably, the ball joint and the ball end joint can have a spherical shape on their outer surface, at least in the region of the retaining section, which corresponds to a shape of the retaining section. Thus, the scales and the ball joints can be positively rotatable and pivotable on the retaining section. In particular, these components can be tilted relative to each other about an axis of rotation on the retaining section.

[0013] Furthermore, according to the invention, the retaining section is arranged between the limiting section and the guide section, is spherically shaped, and has an inner diameter that corresponds to the outer diameter of a first end section of the ball joint. This allows two scales arranged in a row to be optimally guided and rotated relative to each other.

[0014] According to the invention, the scales are arranged around the ball joints such that the respective ball joints are rotatable or pivotable relative to the scales. Preferably, the components of the device are rotationally symmetrical, so that pivoting in all directions is possible. According to an advantageous embodiment, the respective scales can be designed to overlap at least partially and have a rounded or spherical surface.

[0015] The ball joints, connected in a series, preferably form a central point of the device, which is widened circumferentially by the scales. In a device inserted into a hollow structural component, the scales can fit snugly against the hollow structural component on the inside.

[0016] The gap between each pair of scales and the hollow structure component can be minimized by partially overlapping the scales, thus creating a large contact area with the hollow structure component. This prevents the formation of material creases or unintended cross-sectional changes in the hollow structure component when it is bent. The overlap maintains the mobility and degrees of freedom of the interconnected ball joints and scales. In particular, the device, or rather the series of ball joints and scales, can be moved and bent in all directions.

[0017] Due to the rotationally symmetrical design of the device, twisting of the device is impossible. Furthermore, depending on the number of ball joints and scales, the device can be adjusted to any desired length.

[0018] In an advantageous embodiment, the pivot points or rotation points of the ball joints and the scales surrounding the ball joints are identical.

[0019] The device can be used as a retrofit solution for existing bending fixtures as a bending mandrel. The existing tool components for holding and forming the hollow structural component can still be used.

[0020] The individual ball joints and scales are preferably form-fitting and connectable to one another. The end scale and the ball joint can close off the row of scales and ball joints at the end, thus preventing unintentional loosening of the scales and ball joints. A second end of the row is formed by the receiving element and the mandrel shaft.

[0021] The individual components of the device can be made of metal, a metal alloy, plastic, reinforced plastic, ceramic, and the like. In particular, the individual components can consist of one or different materials.

[0022] For example, the ball joints can be made of metal and the scales of plastic to avoid damaging sensitive hollow structure components.

[0023] Unlike previously known scale mandrels, bending this device does not create any gap or space between the scales due to their overlapping design. The modular construction of the device allows the row of scales and ball joints to be adjusted to any desired length.

[0024] According to a further embodiment, the scales and the end scale have a limiting section which is designed as a stop for a ball joint or a ball end joint. Preferably, when the device is bent, the limiting section can abut against a first section of a subsequent or adjacent ball joint, thus limiting the bending radius of the device. Advantageously, the limiting section can be incorporated at the end of the scale or end scale and spaced apart from the holding section. The length spanned by the holding section and the limiting section can essentially correspond to the length of a ball joint.

[0025] Two scales can maintain optimal overlap despite bending of the device if the scales have a guide section. This guide section is designed to selectively engage and guide an adjacent or end scale. Thus, the scales can slide past each other during bending, maintaining a constant clearance to a hollow structural component. Furthermore, the guide sections of the scales can be shaped such that the pivot points of the scales correspond to the pivot points of the ball joints.

[0026] According to a further embodiment, the limiting section is arranged offset from the holding section and has an inner diameter that corresponds to the outer diameter of a first end section of the ball joint. According to a further embodiment, the guide section has an inner diameter that corresponds to the outer diameter of a spherical surface of the scale or end scale. Preferably, the holding section is inserted into the inside of the respective scale and / or end scale between the limiting section and the guide section. The holding section, the limiting section, and the guide section are advantageously rotationally symmetrical and can correspond to circular segments with the same or different radii.

[0027] The device can be particularly efficient and versatile if the scales and / or ball joints are rotatable and / or pivotable relative to each other in all directions. This can be achieved, in particular, by designing the device components with rotational symmetry. This prevents unintentional twisting or tilting of the scales and / or ball joints.

[0028] According to a further embodiment, a clearance can be adjusted between each pair of scales, with the clearance remaining constant regardless of the bending degree of the device. This allows the hollow structural component to be supported uniformly by the device regardless of the bending radius. The constant clearance can be achieved, in particular, by the overlapping of the scales in the area of ​​the guide sections and by ensuring that the scales and the ball joints have the same points of rotation.

[0029] The scales and ball joints connected in a series can be attached at the end in a particularly simple way if the receiving element can be connected to the mandrel shaft via a fastening device.

[0030] The device can be adjusted to any length without tools if at least one ball joint and / or the mounting element is designed to be divisible. For example, the ball joints and / or the mounting element can be made in two parts. This allows the individual ball joints to be connected by splitting and reconnecting them. The scales can circumferentially grip the respective ball joints and lock the multi-part ball joints against loosening. In this way, the scales can fulfill an additional locking ring function.

[0031] Depending on the design, the receiving element can also be made in two parts. Preferably, the receiving element can be positively inserted into an inner section of the mandrel shaft, so that the mandrel shaft secures the receiving element against breakage or separation. The receiving element can also have an internal thread to allow it to be fastened to the mandrel shaft.

[0032] According to an alternative or additional embodiment, the ball joints can also be manufactured in one piece and connected to each other in a row by snapping them together. For this purpose, the ball joints can have perforations, at least in some areas.

[0033] According to a further aspect of the invention, a method for bending a hollow structural component is provided, wherein the device according to the invention can be inserted into a cavity of the hollow structural component in a form-fitting manner.

[0034] In one step, the hollow structural component, together with the attached device, is bent by an external force. The device prevents deformation of the cavity's cross-section during the bending process. Furthermore, the device can serve as a stop for a permissible or intended bending radius.

[0035] Several embodiments of the invention are explained in more detail below with reference to the drawings. The drawings show: Figs. 1a and 1b are sectional views of a receiving element of a device according to one embodiment of the invention. Figs. 2a, 2b, and 2c are views of a ball joint of the device according to the invention. Figs. 3a, 3b, and 3c are views of a mandrel shaft of the device according to the invention. Figs. 4a, 4b, and 4c are views of a scale of the device according to the invention. Figs. 5a, 5b, and 5c are views of an end scale of the device according to the invention. Figs. 6a, 6b, and 6c are views of a ball end joint of the device according to the invention. Fig. 7 is a sectional view of the device according to the invention in its installed state within a hollow structural component. Fig. 8 is a detailed view. Fig. 7 .

[0036] The Fig. 1a und Fig. 1b The figures show sectional views of a receiving element 20 of a device 10 according to the invention in one embodiment. According to the exemplary embodiment, the device 10 is designed as a device 10 for bending hollow structural components 100 and, in particular, as a hinge mandrel.

[0037] In Fig. 1b is a sectional view along a cutting plane AA of the Fig. 1a The receiving element 20 is cylindrical in shape. At a first end 21, the receiving element 20 has a spherical receiving section 22. The receiving section 22 has an end-side opening angle D, which can be, for example, between 90° and 170°.

[0038] The receiving section 22 has an inner diameter A and an outer diameter B. The receiving section 22 can be flexible or bendable at its ends. According to an additional or alternative embodiment, the receiving element can be divisible into at least two parts for opening the receiving section 22.

[0039] At a second end 23 opposite the first end 21, a bore with an internal thread 24 is provided in the receiving element 20. Preferably, the receiving element 20 is rotationally symmetrical along an axis of rotation R.

[0040] The Fig. 2a, Fig. 2b und Fig. 2c Figure 1 shows illustrations of a ball joint 30 of the device 10 according to the invention. The ball joint 30 has a first end section 31 and a second end section 32. The first end section 31 is shaped according to the receiving section 22 of the receiving element 20 and forms an inner spherical receiving chamber 33. The receiving chamber 33 is open at its end with the opening angle D'. The opening angle D of the receiving element 20 and the opening angle D' of the ball joint 30 are the same according to the exemplary embodiment. Furthermore, the ball joint 30 has an inner diameter A' in the first end section 31, which corresponds to the inner diameter of the receiving section 22 of the receiving element 20. An outer diameter B' of the first end section 31 also corresponds to an outer diameter B of the receiving section 22.

[0041] The second end section 32 of the ball joint 30 is essentially spherical and extends from the first end section 31 in the direction of the axis of rotation R. The ball joint 30 is rotationally symmetrical along the axis of rotation R. The first end section 31 is spaced apart from the second end section 32 by a web 34.

[0042] The first receiving section or first end section 31 of the ball joint 30 has an inner diameter A' which also corresponds to an outer diameter A" of the second end section 32. This allows a ball joint 30 with its second end section 32 to be inserted into the first end section 31 of an adjacent ball joint 30'.

[0043] The second end section 32 can be arranged in the receiving space 33 of the first end section 31 and thus be pivotably and rotatably connected. A series of ball joints 30 can be produced by such an arrangement of ball joints 30.

[0044] Here, the first end section 31 forms a first rotation point P1 and the second end section 32 a second rotation point P2. If two ball joints 30, 30' are connected to each other, the rotation points P1, P2 preferably overlap congruently. Depending on the design, the web 34 can be adjusted in length so that a distance X between the rotation points P1, P2 can be adapted.

[0045] The rotation points P1, P2 are designed such that translational movement is prevented, but all rotational degrees of freedom within the opening angles D, D' are maintained. This allows pivoting in all directions and rotation along the axis of rotation R of at least two ball joints 30, 30' arranged in series.

[0046] According to the illustrated embodiment, the ball joint 30 is designed in two parts. In particular, the ball joint 30 can be constructed along a section plane BB from Fig. 2a can be divided. By dividing the ball joint 30, the receiving space 33 can be released, allowing a second end section 32 to be inserted into the receiving space 33 in a form-fitting manner. In the Fig. 2c Figure 30 illustrates a perspective view of the ball joint, in which the section plane BB is shown.

[0047] In Fig. 3a, Fig. 3b und Fig. 3c Illustrations of a mandrel shaft 40 of the device 10 according to the invention are shown. Fig. 3b illustrates a section view along a section plane CC from Fig. 3a . In Fig. 3c A perspective view of the thorn shaft 40 is shown.

[0048] The mandrel shaft 40 is essentially rotationally symmetrical along the axis of rotation R and has a first end 41 and a second end 42. A receiving space 43 for the receiving element 20 is provided at the first end 41 of the mandrel shaft 40. In particular, the receiving element 20 can be positioned in the receiving space 43 such that only the first end 21 of the receiving element 20 projects out of the receiving space 43 at its end.

[0049] The receiving chamber 43 of the mandrel shaft 40 is connected to an end bore 45 via a connecting bore 44 towards the second end 42. The end bore 45 is larger than the connecting bore 44. The receiving element 20 can be screwed to the mandrel shaft 40 through the end bore 45 and the connecting bore 44.

[0050] For tool-side fastening of the mandrel shaft 40, wrench flats 46 are arranged at the second end for tightening / tightening onto a mandrel bar of conventional design, which prevent the mandrel shaft 40 from twisting.

[0051] At the first end 41 of the mandrel shaft 40, a spherical expansion 47 of the receiving chamber 43 is provided. The expansion 47 has an inner diameter C.

[0052] The Fig. 4a, Fig. 4b und Fig. 4c The illustrations show a scale 50 of the device 10 according to the invention. Fig. 4b is a section along the cutting plane DD from Fig. 4a depicted.

[0053] The scale 50 has a spherical surface 51 with an outer diameter C'. The outer diameter C' of the surface 51 preferably corresponds to the inner diameter C of the expansion 47 of the mandrel shaft 40. This allows a scale 50 to be positively inserted into the expansion 47 of the mandrel shaft 40 at its end and to be fixed in position on the mandrel shaft by means of a ball joint 30 via the receiving element 20.

[0054] The scale 50 has a limiting section 52, a holding section 53, and a guide section 54, which form an internal cavity extending through the scale 50. The limiting section 52 transitions into the holding section 53 and then into the guide section 54 in the direction of the axis of rotation R.

[0055] A ball joint 30 can be inserted into the holding section 53 via the guide section 54 with its second end section 32 such that the outer diameter B' of the first end section 31 can fit snugly against an inner diameter B" of the holding section 53. This allows the scale 50 and the ball joint 30 to form a common point of rotation P1. The scale 50 and the ball joint 30 can thus be pivoted and rotated relative to each other along the point of rotation P1.

[0056] The limiting section 52 is also spherical and has an inner diameter B‴, which corresponds to an outer diameter B' of the first end section 31 of the ball joint 30. This allows the limiting section 52 to serve as a lateral end stop for a series of ball joints 30. A maximum relative pivoting angle b between the ball joint 30 and the scale 50 can thus be defined by the shape and size of the limiting section 52.

[0057] The guide section 54 is spherically shaped and has an inner diameter C" which corresponds to an outer diameter C' of the lateral surface 51 of the scale 50. This allows several scales 50 to be arranged in a row and to overlap partially due to the guide section 54. The guide section 54 also defines the rotation point P1 for a scale 50' arranged within it.

[0058] In the Fig. 5a, Fig. 5b und Fig. 5c Figure 1 shows an end scale 60 of the device 10 according to the invention. The end scale 60 essentially corresponds to the scale 50. In contrast to the scale 50, the end scale 60 does not have a guide section 54, but instead transitions at its end into a conical receiving section 64. Fig. 5b This shows the sectioning plane EE from Fig. 5a , which clarifies the shape of recording section 64.

[0059] The terminal scale 60 also has a spherical surface 61, which has the same outer diameter C‴. The outer diameter C‴ of the terminal scale 60 corresponds to an outer diameter C' of the surface 51 of the scale 50.

[0060] Furthermore, the end scale 60 has a holding section 63 and a limiting section 62, which, according to the embodiment, are shaped identically to the scale 50.

[0061] The end scale 60 serves to close off a row of scales 50, 50' at the end. Thus, a row of scales 50, 50' can be clamped between the spherical expansion 47 of the mandrel shaft 40 and the end scale 60. The end scale 60 can project into the guide section 54 of a scale 50, with a ball end joint 70 being inserted into the receiving section 64 of the end scale 60, and the end scale 60 being fixedly attached to a ball joint 30. Such a ball end joint 70 is provided in the Fig. 6a, Fig. 6b und Fig. 6c illustrated.

[0062] The ball end joint 70 has a web 74 and a second end section 72, which are identical to the ball joint 30 in shape and dimensions. In contrast to the ball joint 30, the ball end joint 70 has a first end section 71, which is cylindrically shaped. This allows the first end section 71 of the ball end joint 70 to engage positively with the receiving section 64 of the end plate 60 and lock the end plate 60 in place.

[0063] The Fig. 7 Figure 1 shows a sectional view of the device 10 according to the invention in its installed state within a hollow structural component 100. The hollow structural component 100 is already bent, thus illustrating the interaction of the components 20, 30, 40, 50, 60, and 70 of the device 10. According to the exemplary embodiment, the hollow structural component 100 is designed as a tube.

[0064] The device 10 consists of a receiving element 20, which is connected to the mandrel shaft 40 by means of a screw 90. The receiving element 20 is arranged in the receiving chamber 43 of the mandrel shaft 40. The receiving element 20 projects out of the mandrel shaft 40 at its end such that a scale 50 can fit into the spherical expansion 47 in a form-fitting manner. This allows the spherical expansion 47 to serve as a guide section on the mandrel side. A ball joint 30 arranged in the receiving section 22 of the receiving element 20 locks the scale 50 to the receiving element 20 and the mandrel shaft 40.

[0065] The ball joints 30, 30', 30", 30‴ are arranged in a row and are rotatably and pivotably connected to one another. The respective second end sections 32 are inserted into the first end sections 31 of the adjacent ball joints 30, 30', 30", 30‴. Sheaves 50, 50', 50", 50'" are arranged circumferentially around the ball joints 30, 30', 30", 30‴, with the sheaves 50 in contact with the respective first end sections 31 of the ball joints 30 on the inside in the area of ​​the retaining sections 53. The respective ball joints 30 lock the sheaves 50 in the corresponding guide sections 54 and thus allow an overlap of the sheaves 50. Such an overlap is in the Fig. 8 clarifies which is a detailed view F from Fig. 7 This shows that the overlap creates a free space 80 between two sheds 50, 50' and the hollow structure component 100, the volume of which is minimized.

[0066] The Fig. 7 Furthermore, the figure schematically shows the respective rotation points P1, P2 and the distances X between the rotation points P1, P2. Each ball joint 30 shares the rotation point P1 in the region of the first end section 31 with a scale 50. The rotation points P1 and P2 of two adjacent ball joints 30, 30' are coincident and overlap.

[0067] To illustrate the mode of action of the limiting sections 52, a minimum bending radius r of the device 10 about a bending axis BA is set. Bezugszeichenliste

[0068] 100 Hollow structure component 10 Device / Joint scale mandrel 20 Receiving element 21 First end of the receiving element 22 Receiving section of the receiving element 23 Second end of the receiving element 24 Internal thread 30 Ball joint / first ball joint 30',30'',30‴adjacent ball joints 31 First end section / first receiving section 32 Second end section 33 Receiving space of the first end section 34 Web 40 Mandrel 41 First end of the mandrel 42 Second end of the mandrel 43 Receiving space for the receiving element 44 Connecting bore 45 End bore 46 Wrench flat 47 Spherical expansion 50 Sheath 50',50",50' adjacent sheaths 51 Shell surface 52 Boundary section 53 Holding section 54 Guide section 60 End sheath 61 Shell surface of the end sheath 62 Boundary section 63 Holding section 64 Receiving section of the end sheath 70 Ball joint 71 First end section of the ball joint 72 Second end section of the ball joint 73 Web of the ball joint 80 Clearance 90 Screw / Screw connection A Inner diameter of the receiving section 22 A' Inner diameter of the first end section 31 A" Outer diameter of the second end section 32 b Swivel angle B Outer diameter of the receiving section 22 B' Outer diameter of the first end section 31 B" Inner diameter of the holding section 53 B‴ Inner diameter of the limiting section 52 B A Bending axis of the device C Inner diameter of the expansion 47 of the mandrel shaft 40 C' Outer diameter of the cylindrical surface 51 C" Inner diameter of the guide section 54 C‴ Outer diameter of the end scale 60 D Opening angle of the receiving section 22 D' Opening angle of the receiving space 33 P1 First rotation point P2 Second rotation point Minimum bending radius X Distance between two rotation points

Claims

1. Device (10) for bending hollow structural components (100), in particular tubes, having a mandrel shaft (40) with a received receiving element (20), wherein a row of at least two interconnected ball joints (30, 30') is inserted at the end into the receiving element (20), wherein the row of ball joints (30, 30') is terminated by a ball end joint (70) at an end opposite the receiving element (20), wherein each ball joint (30, 30') has a first end section (31) that forms a first rotation point (P1) and a second end section (32) that has a second rotation point (P2), wherein a ball joint (30) can be inserted with the second end section (32) into the first end section (31) of an adjacent ball joint (30'), wherein each ball joint (30, 30') in the row is circumferentially enclosed by a scale (50, 50') and the ball end joint (70) is circumferentially enclosed by an end scale (60), and the scales (50, 60) overlap at least in some areas, wherein the scales (50) and the end scale (60) have a boundary section (52, 62) which is formed as a stop for a ball joint (30) or a ball end joint (70), and wherein the scales (50) have a guide section (54), wherein the guide section (54) is configured to receive and guide, in certain areas, an adjacent scale (50', 50", 50‴) or an end scale (60), wherein the scales (50) and the end scale (60) have a holding section (53, 63), wherein a ball joint (30) or ball end joint (70) can be inserted into the holding section (53, 63) in a positive-locking manner, and can pivot within the holding section (53, 63), wherein the holding section (53) is arranged between the boundary section (52) and the guide section (54), is spherical in shape, and has an inner diameter (B") that corresponds to an outer diameter (B') of a first end section (31) of the ball joint (30), characterized in that. the respective ball joints are rotatable or pivotable relative to the scales, wherein the scale (50) and the ball joint (30) enclosed by this scale can be pivoted and rotated relative to one another along the first rotation point (P1).

2. Device according to claim 1, wherein the boundary section (52) is arranged offset relative to the holding section (53) and has an inner diameter (B‴) which corresponds to an outer diameter (B') of a first end section (31) of the ball joint (30), wherein the guide section (54) has an inner diameter (C") which corresponds to an outer diameter (C') of a spherical shell surface (51) of the scale (50) or end scale (60).

3. Device according to claim 1 or 2, wherein the scales (50) and / or the ball joints (30) are rotatable and / or pivotable relative to one another in all directions.

4. Device according to one of claims 1 to 3, wherein the receiving element (20) can be connected to the mandrel shaft (40) via a fastening means (90).

5. Device according to one of claims 1 to 4, wherein at least one ball joint (30) and / or the receiving element (20) is configured to be separable.

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