CN108604743B

CN108604743B - Electrical plug contact

Info

Publication number: CN108604743B
Application number: CN201780009902.3A
Authority: CN
Inventors: 克劳斯·施奈德
Original assignee: Phoenix Contact GmbH and Co KG
Current assignee: Phoenix Contact GmbH and Co KG
Priority date: 2016-02-05
Filing date: 2017-02-06
Publication date: 2021-09-03
Anticipated expiration: 2037-02-06
Also published as: CN108604743A; DE102016102036A1; WO2017134289A1

Abstract

An electrical plug contact (1) for connecting at least one conductor (2) or contact pin (3) is described and depicted, having two frame-shaped end regions (4, 5) and a spring section (6) connecting the two end regions (4, 5) to one another, wherein the spring section (6) has an inwardly arched middle section (7) and extends in an insertion direction (E) of the conductor (2) or contact pin (3) that can be inserted through the end regions (4, 5).

Description

Electrical plug contact

Technical Field

The invention relates to an electrical plug contact for connecting at least one conductor or contact pin and to a method for producing such a plug contact from a flat metal strip.

Background

Electrical plug contacts are known from the prior art in various embodiments. Plug contacts are used to establish an electrical connection of a conductor, which is a stripped rigid conductor or a conductor provided with a connecting sleeve, inserted into the plug contact, or of a contact pin on a metal part, such as a conductor rail, which is electrically conductively connected to the plug contact. Furthermore, the electrical plug contact can also be used to electrically connect two electrical conductors to one another, two contact pins to one another, or one electrical conductor to one contact pin to one another by means of a metal component. In this case, the conductor or the contact pin is pressed against the contact section of the metal part by the spring arm, so that such an electrical plug contact is also often referred to as a spring contact on account of its elastic properties.

DE10340332B3 discloses an electrical plug contact which is used only rarely for connecting electrical conductors, but mainly for connecting contact pins or flat plugs. This known plug contact has four spring arms which are shaped as tulip contacts, a connecting region which connects the spring arms to one another, and a connecting region which is adjacent to the connecting region. In this case, the spring arms of the known plug contact, which are arranged opposite one another, are designed such that they form two contact regions. One contact region is used for contacting a contact pin inserted between the spring arms in the longitudinal direction of the spring arms, and the other contact region is used for contacting a contact pin inserted between the spring arms perpendicular to the longitudinal direction of the spring arms.

In addition to plug contacts of this type, which are provided exclusively for contact pins, electrical plug contacts are also provided for connecting electrical conductors. Such plug contacts have a leg spring and a metal part connected to the leg spring, wherein the leg spring is generally substantially U-shaped and has a clamping leg and a supporting leg. The clamping foot spring is connected to the metal part via a support foot, and the clamping foot is used to press the electrical conductor to be connected onto a section of the metal part which together with the clamping foot forms a spring-force clamping connection.

An electrical connection terminal having such a plug contact is known, for example, from DE19817927C 1. The plug contact is formed by a U-shaped leg spring and an L-shaped metal part which is connected to the plug part or the socket part. The metal member has a segment arranged perpendicular to the conductor insertion direction, in which a rectangular opening is formed through which the conductor to be connected can be inserted. The U-shaped clamping leg spring is arranged with the ends of its arms in the opening in such a way that the rear spring bow is located in front of the opening in the wire insertion direction and the clamping leg presses the inserted electrical conductor against the upper edge of the opening, whereby an electrically conductive connection is established between the conductor and the metal part.

DE102004045026B3 discloses an electrical terminal with a plug contact which is composed of a leg spring and a metal part, wherein the leg spring is not U-shaped but is ring-shaped. Furthermore, the receptacle for inserting the electrical conductor to be connected is not formed in a section of the metal part, but in the support leg of the leg spring. In order to fix the clamping leg spring and the metal part, a section of the metal part is inserted through the receptacle into the support leg in the opposite direction to the insertion direction of the conductor to be connected, wherein the section of the metal part is pressed by the clamping leg of the clamping leg spring against a support section formed on the clamping leg spring.

In this case, various known electrical plug contacts or electrical terminals have in common that they have a relatively large dimension in relation to the diameter of the electrical conductor or contact pin to be connected. As the degree of miniaturization of electronic devices continues to increase, less and less connection space is provided for electrical connection devices or electrical plug contacts. A problem can occur in particular if the electrical plug contact is to be used together with a plurality of plug contacts in an electrical connection device, for example a multi-pole socket, rather than individually. Furthermore, the known plug contact has the disadvantage that a high material consumption is required for producing the specially bent metal part and the clamping leg spring, wherein a large part of the material is used as scrap when producing the metal part and the clamping leg spring from a flat metal strip by stamping.

Disclosure of Invention

The invention is therefore based on the object of providing an electrical plug contact which has the smallest possible dimensions and nevertheless enables a simple and reliable connection of an electrical conductor or contact pin. Furthermore, a method is provided, by means of which an electrical plug contact can be produced in a simple manner and with the least possible material consumption.

In the case of an electrical plug contact having the features of the invention, this object is achieved in that the plug contact is formed from two frame-like end regions and a spring section which connects the two end regions to one another, wherein the spring section has an inwardly arched middle section and extends in the insertion direction of a conductor or contact pin which can be inserted through the end regions.

With the electrical plug contact according to the invention, a rigid electrical conductor or a contact pin provided with a terminal sleeve can be directly electrically connected to the plug contact by inserting the conductor or the contact pin through one of the two frame-like end regions into the plug contact. The insertion opening of the plug contact, which is formed by the frame-like end region, does not need to be much larger than the cross section of the conductor to be connected, so that the electrical plug contact according to the invention has only a small size, the longitudinal extent of the plug contact extending parallel to the insertion direction of the conductor to be connected. Furthermore, since the two end regions and the central spring section are connected to one another in one piece, the production and installation of the electrical plug contact is very simple. In particular, there is no need to mechanically fasten a separate clamping leg spring to the plug contact, so that the supporting section provided for this purpose in the prior art can be dispensed with.

In principle, it is possible to connect only one electrical conductor or contact pin to the electrical plug contact. In this case, the electrical conductor or contact pin is inserted through the two frame-like end regions, wherein the electrical conductor or contact pin inserted in this way is pressed against the respective base of the two end regions by the inwardly arched, i.e. arched, middle section of the spring section in the direction of the conductor or contact pin, whereby an electrical contact is established between the conductor and the plug contact or between the contact pin and the plug contact.

However, the electrical plug contact is preferably used for connecting at least one conductor or contact pin to a conductor rail, wherein the conductor rail is connected to the plug contact in such a way that the longitudinal extent of the conductor rail runs parallel to the longitudinal extent of the plug contact and the conductor rail is contacted by the two frame-like end regions in a force-fitting manner. The electrical connection between the conductor and the conductor rail is realized by the spring force of the spring section, by which the inserted conductor is pressed against the conductor rail. If two electrical conductors or two contact pins are electrically connected to the conductor rail by means of electrical plug contacts, the conductor rail is pressed against the two conductors by means of spring sections, wherein in each case one conductor is inserted below the conductor rail in the region of the frame-like end.

In an advantageous embodiment of the electrical plug contact according to the invention, the frame-like end regions each have a slot, so that the end regions are not completely closed in the circumferential direction. If the conductor rail to be connected to the electrical plug contact is a straight conductor rail, the conductor rail can be inserted in the longitudinal direction of the plug contact through the two frame-like end regions of the plug contact. This cannot be achieved, however, if the conductor rail does not have a constant cross section over its entire length, but rather, for example, has a terminal region bent at an angle. If the frame-like end regions of the electrical plug contacts are not completely closed, but the side walls of the end regions each have a slot, the conductor rails can be simply pushed through the slots into the two frame-like end regions.

According to a preferred embodiment of the plug contact according to the invention, the slot in the frame-like end region is not arranged on the same side of the electrical plug contact, but on the side lying opposite. The insertion of the electrical conductor rail with the angled connection region can thus be accomplished in that the plug contact is first placed with its arched middle section on the conductor rail, wherein the longitudinal extent of the plug contact does not correspond to the longitudinal extent of the conductor rail, and subsequently the plug contact is rotated relative to the conductor rail, wherein the conductor rail can be pushed through the gap into the frame-like end region. In this case, the terminal region, which extends at an angle to the longitudinal extent of the conductor rail, is located between the two frame-like end regions of the electrical plug contact, so that the terminal region does not need to be inserted through the end regions.

In order to ensure a secure and permanent connection of the conductor rail to the electrical plug contact and to prevent unintentional release of the conductor rail from the predetermined position to the plug contact, according to a further preferred embodiment of the invention, a stop element is formed on at least one frame-like end region, which together with a mating stop element formed on the conductor rail effects a stop of the conductor rail and the plug contact. In this case, the detent elements formed on the frame-like end regions can be, for example, detent recesses, in which corresponding detent projections or detent projections formed on the electrical guide rails engage when the conductor rail is located in a predetermined position within the frame-like end regions. Likewise, it is also possible to provide a detent recess in the conductor rail and a corresponding detent projection or detent lug in the frame-like end region.

The electrical plug contact is used to connect an electrical conductor to a conductor rail arranged in the plug contact, so that the conductor can be inserted, for example, between the end of the conductor rail and the base plate of the frame-like end region. In this case, for easier insertion of the conductor, the end region can be deflected by applying a force which extends perpendicularly to the longitudinal direction of the plug contact, so that a free space is created between the conductor rail and the base of the frame-like end region, into which the conductor can be easily pushed. Furthermore, the insertion of the conductor can be made easier by this, i.e. according to a further preferred embodiment of the invention, an insertion tongue is formed on the end region, which is remote from the spring region. The insertion tongue has an angle deviating from the longitudinal extension of the plug contact and thus from the longitudinal extension of the conductor rail, so that an insertion correction for the conductor to be connected is formed between the end of the conductor rail protruding from the frame-like end region and the insertion tongue.

According to a further preferred embodiment, an edge or a projection is formed on at least one frame-like end region as a pull-out protection for the conductor to be connected or the contact pin to be connected. This ensures that the electrical conductor or contact pin inserted into the frame-like end region cannot be pulled out again unintentionally from the end region. The edge or the projection is preferably configured to rise in the insertion direction of the conductor, and therefore the edge or the projection is formed without making the insertion of the conductor difficult. The conductor can slide over the edge when the conductor is inserted, while the barb-type edge makes at least the reverse movement of the conductor, i.e. the pulling-out of the conductor from the frame-like end region, difficult.

The electrical plug contact according to the invention can be produced simply from a flat metal strip as a stamped and bent part, wherein usually a large number of corresponding plug contacts are stamped from a larger metal strip and then bent over to give them a final shape.

The method according to the invention for producing an electrical plug contact from a flat metal strip is characterized in that first the basic contour of the plug contact is punched out in a first step. The basic contour has two flat end regions and a central region which connects the two end regions to one another, wherein the two end regions each extend perpendicularly outward from the central region in opposite directions. The basic contour of the plug contact thus approximates a Z-shape, with an angle of 90 ° between the two end regions and the central region.

In the method according to the invention, the basic contour of the plug contact is stamped from the metal strip in such a way that the longitudinal extent of the central region of the basic contour extends at an angle of 45 ° to the longitudinal extent of the metal strip. The basic contour of the respective plug contact is therefore stamped from a preferably rectangular metal strip "obliquely" to the longitudinal extent of the metal strip. This results in only a small portion of the metal strip remaining as scrap or waste after stamping the basic contour of the plug contact, so that the material used for producing the plug contact is consumed only little.

After stamping or punching out the basic contour of the plug contact, the finished plug contact can be produced from the planar basic contour by a simple bending process. In this case, in a first step, the central region is slightly bent perpendicular to the plane of extension of the central region, so that an arched central section or an arched spring section is produced. In a next step, the end region is bent along three curved edges which run parallel to one another and perpendicular to the longitudinal extension of the end region, so that a frame-like end region with four side walls is produced. In principle, the sequence of these two steps can be interchanged, so that the frame-like end regions are first bent and then the arched central region is produced.

If it is desired that the frame-like end regions of the finished electrical plug contact are not completely closed, but rather each have a slot, this can be achieved simply by virtue of the distance x between the first bent edge and the second bent edge₁Is greater than the distance x between the third curved edge and the free end of the end region₂The first curved edge is arranged at the transition from the intermediate region to the end region. After bending the end region, a gap forming a frame-like end region is then produced between the free end of the end region and the intermediate region or the section of the spring section lying opposite the free end, through which gap the conductor rail can be pushed or rotated into the frame-like end region.

If it is desired that the frame-like end region is completely closed in the finished electrical plug contact, this can be achieved by virtue of the distance x between the first bent edge and the second bent edge₁Equal to the distance x between the third curved edge and the free end of the end region₂The first curved edge is arranged at the transition from the middle area to the end area so that the side walls lying opposite one another have the same length. In a further step, the free ends of the end regions are connected to the edge sections of the central region which lie opposite the free ends. The connection of the free ends of the end regions to the edge sections of the intermediate region can be effected here, for example, by crimping or welding, in particular laser welding.

It is also possible to produce the structure of the edge on the side wall of the end region simply by stamping and then bending, so that the edge extends after bending of the end region in the direction of the oppositely situated side wall and thus in the inner region of the frame-like end region.

Drawings

In particular, there are various possibilities for implementing and improving the plug contact according to the invention. Reference is made to the following description of the preferred embodiments, taken in conjunction with the accompanying drawings. In the drawings:

figure 1 shows a perspective view of an electrical plug contact according to the invention,

fig. 2 shows the electrical plug contact according to fig. 1, with an inserted conductor rail and an electrical conductor to be connected,

fig. 3 shows an electrical plug contact from the side, with an inserted conductor rail and two electrical conductors connected to the plug contact,

fig. 4 shows the electrical plug contact according to fig. 1 from the side, with the contact pin inserted,

figure 5 shows a perspective view of the electrical plug contact and the conductor rail in the unfinished state,

FIG. 6 shows the electrical plug contact according to FIG. 2 with an inserted conductor and a pull-out lock, an

Fig. 7 shows a metal part from which a plurality of plug contacts can be produced by stamping and bending.

Detailed Description

Fig. 1 to 6 show an electrical plug contact 1 for connecting at least one conductor 2 or contact pin 3 (see fig. 4). The electrical plug contact 1, which is illustrated separately in fig. 1, has two frame-

like end regions

4, 5 and a spring section 6 which connects the two

end regions

4, 5 to one another, wherein the spring section 6 is formed such that it has an inwardly arched middle section 7. The electrical plug contact 1 is therefore constructed in one piece, wherein the plug contact 1 can be produced from a flat metal part by bending. In particular, spring steel strips can be used as the material of the plug contact 1.

Fig. 2 shows the electrical plug contact according to fig. 1 rotated by 180 °, wherein a straight conductor rail 8 is additionally arranged in the plug contact 1. The two frame-shaped

end regions

4, 5 surround the conductor rail 8 in a force-fitting manner, so that the conductor rail 8 is reliably arranged and held in the plug contact 1. As shown in fig. 2, the longitudinal extension L of the conductor rail 8_sWith the longitudinal extension L of the plug contact 1_kExtending parallel and also parallel to the insertion direction E of the electrical conductor 2 to be connected. As can be seen from fig. 6, if the electrical conductor 2 is inserted into the plug contact 1, the conductor is pressed against the lower conductor rail 8 by the arched middle section 7 of the spring section 6. It can also be seen from fig. 2 that the space required for the plug contact 1 for connecting the electrical conductor 2 to the conductor rail 8 is very small, the height and width of the plug contact 1, i.e. the perpendicular to the longitudinal extent L of the plug contact, being very small_kIs only slightly larger than the sum of the respective dimensions of the conductor 2 and the conductor rail 8.

As shown in fig. 3, the electrical plug contact 1 can be used not only for connecting the conductor 2 to a conductor rail 8 arranged in the plug contact 1, but also for electrically connecting the two conductors 2, 2' via the conductor rail 8. For this purpose, in each case two electrical conductors 2, 2 'are inserted into the frame-

like end regions

4, 5 of the plug contact 1 in such a way that the conductors 2, 2' are clamped between the base of the conductor rail 8 and the base 9 of the

respective end region

4, 5. The conductor rail 8 is pressed against the inserted conductor 2, 2 'by the arched central region 7 of the spring section 6, so that a good and durable electrical contact between the conductor 2, 2' and the conductor rail 8 is ensured. In order to be able to mount the side walls S of the conductor rails 8 and the base plate 9 forming the

end regions

4, 5₃Between which the electrical conductor 2, 2' is inserted, by extending perpendicular to the longitudinal direction L of the plug contact 1_kThe force F acting presses the

respective end region

4, 5 downwards, thereby opening the connection chamber for the conductor 2, 2'. For example, as shown in the end region 4 on the right in fig. 3, the downward pressing of the frame-

like end regions

4, 5 can be easily accomplished with a finger.

Fig. 4 shows the use of an electrical plug contact 1, in which only one contact pin 3 is connected to the plug contact 1. In this case, the contact pin 3 is inserted through the two

end regions

4, 5 of the plug contact 1, so that the contact pin 3 is pressed downward in the drawn orientation against the respective base 9 of the

end regions

4, 5 by the inwardly arched, i.e. in the direction of the contact pin 3, intermediate region 7 of the spring region 6. The clear width between the lower edge of the undeflected, arched intermediate section 6 and the base 9 of the

end regions

4, 5 must be slightly smaller than the corresponding dimension of the contact pin 3, so that the spring section 6 exerts a sufficient contact force on the contact pin 3.

As shown in fig. 2 and 6, if the conductor rail 8 is a straight conductor rail with a constant cross section over its longitudinal extent, the conductor rail 8 can easily be guided along the longitudinal extent L of the plug contact 1_kIs inserted through both

end regions

4, 5. In contrast, if the conductor rail 8 has an angled terminal region 10 as shown in fig. 5, it is not possible to push the conductor rail 8 axially into the

end regions

4, 5.

According to the preferred embodiment, which is depicted in the figures, the two frame-

like end regions

4, 5 are not completely closed, but each have a slot 11, which is formed by the side wall S₂Longer than the opposite side wall S₄And (4) generating. The conductor rail 8 can then be connected to the plug contact 1 by this, i.e. the conductor rail 8 is pivoted into the frame-

like end regions

4, 5 via the slot 11. For this purpose, the plug contact 1 according to fig. 5 is first placed with its arched middle section 7 on the conductor rail 8, wherein the angled connection region 10 of the conductor rail 8 is located between the two

end regions

4, 5. Subsequently, the plug contact 1 and the conductor rail 8 are rotated relative to one another, wherein the conductor rail 8 can be introduced into the

end regions

4, 5 through the slot 11. As indicated by the arrow in fig. 5, the plug contact 1 can be rotated, for example, clockwise. Alternatively, the power rail 8 can also be rotated counter to the clockwise direction.

In order to reliably prevent unintentional pivoting back of the plug contact 1 or pivoting out of the conductor rail 8 from the frame-

like end regions

4, 5, a latching mechanism can be formed between the frame-

like end regions

4, 5 and the conductor rail 8. For this purpose, for example, the side walls S of the frame-shaped

end regions

4, 5 opposite the top face of the conductor rail 8 can be provided₁A detent recess 12 is formed and a corresponding detent projection 13 is formed on the upper side of the conductor rail 8.

As can be seen from fig. 3 and in particular from the enlarged detail, an edge 14 is formed on the base plate 9 of the frame-like end region 4, which serves as a pull-out protection for the connected conductor 2. The edge 14 therefore has no effect on the insertion of the conductor 2 into the frame-like end region 4, the edge 14 being configured such that it rises in the insertion direction E of the conductor 2. This allows the conductor 2 to be inserted into the frame-like end region 4 with a low expenditure of force, while the edge 14 acting as a barb makes it at least difficult to pull the conductor 2 out of the end region 4. In order to further simplify the insertion of the conductor 2 into the frame-like end region 4, a lead-in tongue 15 is additionally arranged on the base plate 9 of the end region 4, which lead-in tongue together with the end of the conductor rail 8 projecting from the end region 4 forms a lead-in correction for the conductor 2.

Fig. 6 shows a plug contact 1 with an inserted conductor rail 8 and a conductor 2 connected to the conductor rail 8, together with a part of a housing 16 accommodating the plug contact 1, and thus a part of an electrical connection terminal. In this case, a latching hook 17 is formed on a part of the housing 16, which hooks over a flange 18 of a terminal sleeve 19 of the conductor 2. A mechanical pull-out lock for the electrical conductor 2 with the connecting sleeve 19 is thereby achieved, which can also be released again by means of a simple tool, for example the tip of a screwdriver.

Fig. 7 shows a flat metal strip 20 from which a plurality of plug contacts 1 can be produced by stamping and bending. For this purpose, the basic contour 21 of the plug contact 1 is first stamped, wherein the basic contour 21 has two flat end regions 22 and an intermediate region 23 which connects the two end regions 22 to one another. The end regions 22 in this case each extend perpendicularly outward in opposite directions from the central region 23, so that an approximately Z-shaped basic contour 21 is formed. In this case, by means of the longitudinal extension L of the intermediate region 23_MThe extension at an angle α of 45 ° to the longitudinal extension L of the metal strip 20 enables a particularly material-saving and low-waste production of the basic contour 21 of the plug contact 1. The basic contours 21 of the individual plug contacts 1 can thereby be arranged very densely with respect to one another in the metal strip 20, wherein only a relatively small portion of the metal strip 20 remains as scrap after stamping the individual basic contours 21.

After the stamping of the base contour 21, the central region 20 is bent perpendicular to its plane of extension, so that the arched central section 7 of the plug contact 1 is produced. By means of three curved edges B extending parallel to one another₁、B₂、B₃The end regions 22 are bent over one after the other to produce the frame-

like end regions

4, 5, resulting in a structure having four side walls S₁、S₂、S₃And S₄The frame-

like end regions

4, 5.

In this case, it is possible to easily produce the frame-shaped

end regions

4, 5 that are not completely closed, i.e. the first curved edge B provided at the transition from the central region 23 to the end region 22₁And a second curved edge B₂X is the distance between₁Greater than at the third curved edge B₃And the free end 24 of the end region 22₂。

As described above, the electrical plug contact 1 can be produced in a simple manner, has a relatively small size and requires only a very low material consumption for the production of the plug contact. For example, due to the small dimensions, a plurality of plug contacts 1 can be used in a multi-pole socket having smaller dimensions, for example an M12 socket, in which the individual plug contacts 1 are arranged parallel to one another.

Claims

1. Electrical plug contact (1) for connecting at least one conductor (2), having two frame-shaped end regions (4, 5) and a spring section (6) connecting the two end regions (4, 5) to one another, wherein the spring section (6) has an inwardly arched middle section (7) and extends in an insertion direction (E) of the conductor (2) which can be inserted through the end regions (4, 5), wherein the end regions (4, 5) extend in three directions (L) parallel to one another and in the longitudinal direction of the plug contact (1)_k) Parallel extending curved edges (B)₁，B₂，B₃) Is bent to produce and has four side walls (S)₁，S₂，S₃，S₄) Characterized in that the frame-like end regions (4, 5) each have a slit (11) so that they are not completely closed, the slits (11) in the frame-like end regions (4, 5) being arranged on opposite sides.

2. Electrical plug contact (1) according to claim 1, characterised in that a conductor rail (8) is connected to the plug contact (1) in such a way that the longitudinal extent (L) of the conductor rail (8)_s) With the longitudinal extension (L) of the plug contact (1)_k) The conductor rails (8) extend in parallel and are in force-fitting contact with the frame-shaped end regions (4, 5).

3. Electrical plug contact (1) according to claim 2, characterised in that a stop element (12) is formed on at least one frame-like end region (4, 5), which together with a mating stop element (13) formed on the conductor rail (8) effects a stop of the conductor rail (8) and the plug contact (1).

4. Electrical plug contact (1) according to claim 1, characterised in that an edge (14) or a projection is formed on at least one frame-like end region (4, 5) as a pull-out safeguard for the conductor (2) to be connected, wherein the edge (14) or the projection is raised in the insertion direction (E) of the conductor (2) which can be inserted through the end region (4, 5).

5. The electrical plug contact (1) according to claim 1, characterised in that a lead-in tongue (15) is formed on at least one frame-like end region (4, 5) remote from the spring section (6).

6. Electrical connection terminal having a housing (16) and an electrical plug contact (1) according to one of claims 1 to 5 arranged in the housing (16), characterized in that a latching hook (17) is provided which forms a pull-out lock for the connected conductor (2) with a connection sleeve (19) of the connected conductor (2).

7. Method for producing an electrical plug contact (1) according to one of claims 1 to 6 from a flat metal strip (20), characterized by the following steps:

blanking a basic contour (21) of the plug contact (1), wherein the basic contour (18) has two end regions (22) and an intermediate region (23) connecting the two end regions (22) to one another, wherein the two end regions (22) each extend perpendicularly outward from the intermediate region (23) in opposite directions, and wherein a longitudinal extension (L) of the intermediate region (23)_M) Extends at an angle alpha of 45 DEG to the longitudinal extension (L) of the metal strip (20),

bending the intermediate region (23) perpendicularly to the plane of extension of the intermediate region (23) so as to produce an arched intermediate section (7),

along three curved edges (B) extending parallel to each other and perpendicular to the longitudinal extension of the end region (19)₁，B₂，B₃) Bending the end region (22) so as to produce a tube having four side walls (S)₁，S₂，S₃，S₄) Of the frame-like end regions (4, 5).

8. Method according to claim 7, characterized in that the first curved edge (B)₁) And a second curved edge (B)₂) X is the distance between₁Greater than the third curved edge (B)₃) And a free end (24) of the end region (22) is arranged at a distance x₂The first curved edge is arranged at the transition from the middle region (23) to the end region (22).

9. Method according to claim 8, characterized in that the first curved edge (B)₁) And a second curved edge (B)₂) X is the distance between₁Equal to the third curved edge (B)₃) And the free end (24) of the end region (22) is arranged at a distance x₂The first curved edge is arranged at the transition from the middle region (23) to the end region (22), and the free end (24) of the end region (22) is connected in a further step to an edge section of the middle region (23).

10. Method according to claim 7, characterized in that the side wall (S) in at least one end region (22)₃) In that an edge (14) or a projection is stamped and/or bent out, so that after bending the end region (22) the edge (14) or the projection is directed towards the oppositely situated side wall (S)₁) Extend in the direction of (a).

11. Method according to claim 7, characterized in that of at least one end region (22)Side wall (S)₃) Has an insertion tongue (15) extending perpendicularly to the longitudinal extension of the end region (22), and the insertion tongue (15) is bent in a further step in such a way that the insertion tongue (15) is inclined to the adjacent side wall (S)₃) Extend in a plane.