EP3720627B1 - Method for producing a connecting element - Google Patents

Description

The invention relates to a method for producing a connecting element with at least two spherical sections, with two spherical sections directly adjacent to one another or with two spherical sections being connected to one another by means of a connecting section, the rolling of an at least partially cylindrical blank between at least two rolling tools and the shaping of the at least two spherical sections and optionally the connecting section is provided during rolling.

A connecting element with two spherical sections is from the German published application DE 10 2011 087 286 A1 known. The spherical sections directly adjoin one another. The connecting element should be manufactured very simply and cost-effectively from mass-produced individual balls that simply need to be connected to one another. The individual balls can be connected to the connecting element, for example by welding. Clip elements are then placed onto the spherical sections, which in turn are connected to one of the components to be connected to one another. It is intended to line up more than two balls to form a connecting element.

From the US patent specification US 1,469,174 , which forms the basis for the preamble of claim 1, a method for producing a connecting element with at least two spherical sections is known, with two spherical sections being connected to one another by means of a connecting section. The connecting element is produced by rolling a cylindrical, one-piece blank between at least two rolling tools. During rolling, at least two spherical sections and at least one connecting section are produced.

From the US patent specification US 4,489,581 The production of a connecting element from a cylindrical blank is known. When rolling between two rolling tools, two spherical sections and a connecting section between the spherical sections are produced. Slugs on the spherical sections are separated during rolling. The element thus rolled is then pressed flat to obtain the desired connecting element, which has two disc-like elements and a connecting web extending between the disc-like elements.

From the German disclosure document DE 32 29 605 A1 the production of screws is known. A thread is rolled onto a cylindrical shaft. The rolling jaws have a shaping surface for the shaft end of the screw and a shearing edge for excess material from the blank. During rolling, a slug is separated.

From the European disclosure document EP 1 749 595 A1 the production of a connecting element with a spherical section is known. In rolling, a blank is supported on a small diameter cylindrical section adjacent to a shaft with a hexagonal cross-section.

From the US patent specification US 1,337,640 The production of balls by rolling cylindrical blanks is known.

The invention is intended to provide an improved method for producing a connecting element.

According to the invention, a method for producing a connecting element with the features of claim 1 is provided. Further developments of the invention are specified in the subclaims.

A method for producing a connecting element with at least two spherical sections is provided, with two spherical sections directly adjacent to one another or with two spherical sections being connected to one another by means of a connecting section, in which the rolling of an at least partially cylindrical, one-piece blank between at least two rolling tools and the shaping of the at least two spherical sections and optionally the connecting section are provided during rolling.

Surprisingly, a connecting element with at least two spherical sections can be produced by a single cold forming process. The welding of the spherical sections to the connecting element, which is provided in the prior art, can therefore be omitted and both the spherical sections and the connection of the spherical sections are produced in a single operation. Surprisingly, by rolling a cylindrical blank, it is possible to achieve a very large degree of deformation, so that the two spherical sections can be formed. The connecting element produced according to the invention can thereby reliably fulfill its intended function, namely being locked with a clip element. As rolling tools Roll rolling tools or two flat rolling jaws can be provided. The blank is preferably circular cylindrical. The blank can be separated from a wire coil by the rolling tool or a separate separating device. This makes handling the blank easier. By rolling, the spherical shape can deviate from a spherical shape and, for example, rotationally symmetrical shapes can be produced, which are, for example, more bulbous than balls and can therefore, if necessary, provide more material for pressing operations. This can be advantageous if the spherical sections are pressed directly into through openings in sheets and, to secure the press-in position, projections are pressed out of the spherical section, which then protrude from the spherical section above and below the sheet.

In a further development of the invention, the shaping takes place over the course of 10 to 15 revolutions of the blank.

10 to 15 revolutions of the blank relative to the rolling tool are sufficient to form the at least two spherical sections and optionally connecting sections between the spherical sections from a cylindrical, in particular circular cylindrical, blank. With the method according to the invention, connecting elements can be produced quickly and in large quantities. The connecting elements can be made from a blank without waste, i.e. without slugs.

In a further development of the invention, a slug is separated from the outer ends of the spherical sections at the end of the rolling process by means of a separating edge on a rolling tool, the separating edge extending beyond the central longitudinal axis of the connecting element.

When rolling the blank, slugs are usually created that absorb excess material from the blank that is not required for producing the connecting element. Such a slug is created, for example, by the fact that the blank must first be held at one of its ends when it is inserted into the rolling tool. According to the invention, this slug or two slugs at the opposite ends of the almost finished connecting element can then be separated automatically by means of a separating edge on a rolling tool. In this way, the connecting element can be manufactured entirely by rolling and, as a rule, no further processing is required.

According to the invention, the blank is held at least before the start of rolling on a feed head of the blank, the feed head being disk-like and protruding in the radial direction beyond the blank, which is cylindrical with the exception of the feed head.

Such a disk-like feed head makes it easier to hold the blank before rolling begins and thus also makes it easier to insert the blank into the rolling tool.

In a further development of the invention, the feed head is separated together with the separation of one of the slugs.

The connecting element can therefore be completely finished using a single rolling process.

In a further development of the invention, the blank has a circular cylindrical base body.

The blank can, for example, be designed as a piece of wire and in particular a disk-like feed head can be produced by upsetting the piece of wire.

In a further development of the invention, two flat rolling jaws are provided as rolling tools.

Using flat rolling jaws, the connecting element can be manufactured in large quantities and with tight tolerances.

In a further development of the invention, each flat rolling jaw has two trough-shaped recesses which widen and deepen in the intended rolling direction.

In the method according to the invention, the two flat rolling jaws are displaced relative to one another, with the blank being accommodated between the flat rolling jaws. The blank then rolls on the two flat rolling jaws and is thereby deformed at the same time. The forming takes place gradually from the cylindrical, in particular circular cylindrical, blank to the spherical sections through the widening trough-shaped recesses. As stated, approximately 10 to 15 revolutions of the blank are sufficient to completely form the connecting element.

In a further development of the invention, the two trough-shaped recesses are separated by means of a central web running parallel to the intended rolling direction.

By means of such a central web, a constriction is formed between the two spherical sections of the connecting element during rolling and thus the relative movement between the blank on the one hand and the two flat rolling jaws on the other. Alternatively, a connecting section can be formed between the two spherical sections using the central web.

With the method according to the invention, a connecting element with at least two spherical sections is produced, with two spherical sections directly adjacent to one another or with two spherical sections being connected to one another by means of a connecting section, in which the connecting element is produced from a one-piece blank by means of rolling between at least two rolling tools.

Two spherical sections directly adjoin one another and are separated from one another by means of a constriction, with a diameter of the connecting element at the thinnest point of the constriction being between a third and half of a diameter of the spherical sections.

By dimensioning the constriction in this way, on the one hand, a secure connection of the two spherical sections is achieved and, on the other hand, it can also be ensured that the spherical sections can each be clipped into a clip element, which then holds the spherical sections over an angle of more than 180 ° surrounds and is then securely held on the spherical section.

A rolling tool for producing a connecting element using the method according to the invention has two flat rolling jaws, each flat rolling jaw having two trough-shaped recesses which widen and deepen in the intended rolling direction.

The two trough-shaped recesses are separated by a central web that runs parallel to the intended rolling direction.

At least one of the trough-shaped recesses is provided on its side opposite the central web, at least in an end section with the greater width and depth of the recess, with a separating edge which extends beyond a central longitudinal axis of the connecting element produced in order to separate a slug.

By means of such a separating edge, it is possible to simultaneously separate the slug during the last revolution or the last revolutions in the rolling process. For example the separating edge extends beyond an angle of 180° for spherical sections. So if the almost finished connecting element, on which the slug is still hanging, is moved into the area of the separating edge, the separating edge ensures that the slug is separated as the almost finished connecting element continues to roll on the two flat rolling jaws.

The central web has a substantially constant width over the entire length of the respective flat rolling jaw.

Fig. 1

eine Seitenansicht eines Rohlings zur Herstellung eines Verbindungselements mit dem erfindungsgemäßen Verfahren,

Fig. 2

eine Draufsicht auf eine Flachwalzbacke eines Walzwerkzeugs zur Verwendung bei dem erfindungsgemäßen Verfahren,

Fig. 3

eine schematische Draufsicht auf ein Verbindungselement mit zwei bereits abgetrennten Butzen,

Fig. 4

eine schematische Schnittansicht des Flachwalzbackens der Fig. 2 mit einem darin angeordneten Verbindungselement,

Fig. 5

eine schematische, abschnittsweise Draufsicht auf ein Walzwerkzeug zum Herstellen eines Verbindungselements,

Fig. 6

eine schematische, abschnittsweise Seitenansicht eines weiteren Walzwerkzeugs zum Herstellen des Verbindungselements,

Fig. 7

eine abschnittsweise schematische Draufsicht auf eine Flachwalzbacke eines Walzwerkzeuges und ein damit hergestelltes Verbindungselements, und

Fig. 8

ein Verbindungselement gemäß einer weiteren Ausführungsform.

Further features and advantages of the invention result from the claims and the following description of a preferred embodiment of the invention in conjunction with the drawings. Individual features shown in the drawings and described in the description can be combined with one another in any way without exceeding the scope of the invention. This also applies to the combination of individual features without further individual features with which they are shown or described in connection. Shown in the drawings:

Fig. 1

a side view of a blank for producing a connecting element using the method according to the invention,

Fig. 2

a top view of a flat rolling jaw of a rolling tool for use in the method according to the invention,

Fig. 3

a schematic top view of a connecting element with two already separated slugs,

Fig. 4

a schematic sectional view of the flat rolling die Fig. 2 with a connecting element arranged therein,

Fig. 5

a schematic, sectional top view of a rolling tool for producing a connecting element,

Fig. 6

a schematic, sectional side view of a further rolling tool for producing the connecting element,

Fig. 7

a sectional schematic plan view of a flat rolling jaw of a rolling tool and a connecting element produced with it, and

Fig. 8

a connecting element according to a further embodiment.

Fig. 1 shows a side view of a blank 10 for producing a connecting element using the method according to the invention. The blank 10 has a circular cylindrical base body 12 and a disk-like feed section 14. The disk-like feed section 14 projects in the radial direction beyond the circular cylindrical base body 12. The feed section 14 serves to hold the blank 10 while the blank 10 is being fed to a rolling tool and, if necessary, to guide it during the start of the rolling process. The feed section 14 is automatically separated at the end of rolling in the method according to the invention. This will be explained below.

The circular cylindrical base body 12 is formed during rolling into two spherical sections of the connecting element and optionally a connecting section between the two spherical sections. A slug is formed at both ends of the circular cylindrical base body 12 during rolling, see Fig. 3 , which absorbs excess material and is automatically separated at the end of rolling.

Fig. 2 shows a top view of a flat rolling jaw 16 for use in the method according to the invention. To produce a connecting element, two identical flat rolling jaws 16 are used, which hold the blank 10 between them and are then moved relative to one another. As a result of this displacement movement, the blank 10 then rolls on the flat rolling jaw 16, in Fig. 2 from left to right, and is simultaneously formed between the two flat rolling jaws to form the connecting element according to the invention. Forming is carried out by rolling and, as a result, by cold forming.

The flat rolling jaw 16 has a base body 18 in the form of an elongated cuboid, see also Fig. 4 . Two trough-shaped recesses 20, 22 are provided in the top of the base body 18, which are located in the intended rolling direction Fig. 2 So from left to right, widen and deepen. The two trough-shaped recesses 20, 22 are separated from one another over their entire length by a central web 24, see also Fig. 4 . The central web 24 has a constant width over the entire length of the flat rolling jaw 16.

The inner edges of the trough-shaped recesses 20, 22, which are formed by the central web 24 in both the trough-shaped recess 12 and the trough-shaped recess 22, are therefore parallel to one another. The respective outer edges 26, 28 however, run in the intended rolling direction Fig. 2 so from left to right, apart.

In the left section of the trough-shaped recesses 20, 22 in Fig. 2 several ribs 30 arranged one behind the other are arranged outside the side edges 26, 28. The ribs 30 each form a driving track, which, however, only extends parallel to the trough-shaped recesses 20, 22 between approximately a third and half of the length. The ribs 30, which form the driving tracks, serve to take the blank along at the start of the rolling process, so that it does not slip relative to the flat rolling jaws 16, but rather rolls on the flat rolling jaws 16.

In the method according to the invention, the blank 10 is completely formed into the connecting element 40 in the course of approximately 10 to 15 revolutions relative to the flat rolling jaws 16 Fig. 3 is shown, transformed.

In an end section 32 of the flat rolling jaw 16, into which the blank only arrives in the course of the last revolution or last two revolutions relative to the flat rolling jaws 16, the side edges 26, 28 of the flat rolling jaw 16 are designed as separating edges and extend over the central longitudinal axis of the blank 10 or the almost completed connecting element 40. In the representation of the Fig. 3 the completed connecting element 40 and its central longitudinal axis 42 can be seen. A slug 44, 46 can be seen above and below the connecting element 40, the one in Fig. 3 upper slug is still connected to the feed section 14. When the connecting element 40 is formed from the circular cylindrical base body 12 of the blank 10, the slugs 44, 46 form outside the trough-shaped recesses 20, 22, since excess material is displaced from the trough-shaped recesses 20, 22 and flows into the slugs 44, 46. These slugs are when the blank 10 reaches the area of the end section 32 of the trough-shaped recesses 20, 22, see Fig. 2 , still connected in one piece to the blank 10. Since the outer side edges of the trough-shaped recesses 20, 22 in the end section 32 now extend beyond the central longitudinal axis 42 of the connecting element 40 and are each designed as a separating edge, the slugs 44, 46 are during the unrolling of the blank 10 or the almost finished connecting element 40 separated from the connecting element 40. After the connecting element 40 then leaves the end section 32, the state is Fig. 3 reached. As can be seen, the connecting element 40 is completely formed and the slugs 44, 46 have been automatically separated from the connecting element 40. With two identical flat rolling jaws 16, there is only one side edge, for example the side edge 28, designed as a separating edge. Since the two flat rolling jaws 16 are placed one on top of the other, the separating edge on the lower flat rolling jaw 16 can separate one slug and the separating edge on the upper flat rolling jaw can separate the other slug.

Based on Fig. 3 It can be seen that the connecting element 40 has a first spherical section 46 and a second spherical section 48, which each have the same diameter and are separated from one another by a constriction 50. The two spherical sections 54, 56 are connected to one another in one piece in the area of the constriction 50, since they were formed by cold forming during the rolling of the blank 10. The diameters of the two spherical sections 54, 56 are the same size and the diameter in the area of the constriction 50 is approximately one third to half the diameter of the spherical sections 54, 56.

The connecting element 40 is used to connect two workpieces. For this purpose, the two workpieces are each connected to a clip element which has a spherical recess that fits the spherical sections 54, 56 and consists of an elastically resilient material, for example a suitable plastic. The spherical section 54 of the connecting element 40 is then clipped into the clip element of the first workpiece and the spherical section 56 into the clip element of the second workpiece. The two workpieces are then securely connected to one another via the connecting element 40.

Based on the representation of the Fig. 4 It can be seen how the constriction 50 is formed between the two spherical sections 54, 56 of the connecting element 40 during rolling through the central web 24. The central web 24 is pressed into the cylindrical base body 12 of the blank 10 and displaces material to the left and right into the spherical sections 54, 56 while the blank 10 is rolling on the flat rolling jaw 16.

The representation of the Fig. 4 is schematic. During rolling, the blank 10 lies between two flat rolling jaws 16, with an upper flat rolling jaw for the sake of clarity Fig. 4 is not shown.

Fig. 4 shows schematically the state in which the connecting element 40 is already completely formed and the connecting element 40 is thus located in the end section 32 of the trough-shaped recesses 20, 22, cf. Fig. 2 . In this state the slugs 44, 46, cf. Fig. 3 , has already been completely separated. For this purpose, the side edges 26, 28 extend in the end region 32 beyond the central longitudinal axis 42 of the connecting element 40.

Through the method according to the invention, the connecting element 40 can be completely formed in a single rolling process. At the end of this rolling process, the slugs 44, 46 are separated so that the connecting element 40 is then completely finished.

The representation of the Fig. 5 shows a schematic, sectional top view of a rolling tool 60 according to a further embodiment of the invention, with only one in the illustration Fig. 5 Flat rolling jaw 64 lying under a blank 62 is shown. The flat rolling jaw 64 is essentially identical to the flat rolling jaw Fig. 2 educated. However, the blank 62 does not have a feed section and is rather separated to the required length at the beginning of the rolling track of the flat rolling jaw 64 from a supplied wire 66, for example from a wire coil, by means of a schematically shown cutting tool 68. The cutting tool 68 can be designed, for example, as a pair of scissors, a saw or the like. Separating the cylindrical blank 62 only when the blank 62 is already arranged in the rolling tool 6ß makes the handling of the blank 62 considerably easier; in particular, the wire 66 is fed from a wire coil, for example. As long as the blank 62 is still connected to the remaining wire 66, the blank can be easily inserted between two flat rolling jaws of the rolling tool 60. Only when the end section of the wire 66, which later forms the blank 62, is correctly positioned relative to the rolling tool 60 and specifically, see Fig. 5 , at the beginning of the rolling path the flat rolling jaws 64 is arranged, the blank 62 is separated from the remaining wire 66 by means of the cutting tool 68.

Fig. 6 shows a sectional side view of a rolling mill train 70 according to a further embodiment of the invention. The rolling tool 70 has a lower flat rolling jaw and an upper flat rolling jaw 74, which can be designed identically to one another and which accommodate the cylindrical blank 62 between them. The blank 62 can, as shown in the Fig. 5 was explained, form the free end of a wire 66.

The two flat rolling jaws 72, 74 are each provided with a separating edge 76, 78, which are intended to separate a piece of the wire at the beginning of the rolling movement and thereby form the blank 62. As in Fig. 6 is indicated, the lower flat rolling jaw 72 is moved to the left and the upper flat rolling jaw 74 is moved to the right. A height of the separating edge 76 of the lower flat rolling jaw 72 increases Fig. 6 from left to right and a height of the separating edge 78 of the upper flat rolling jaw 74 increases Fig. 6 from right to left. If the two flat rolling jaws 72, 74 are in Fig. 6 When moved horizontally to the left or right, the separating edges 76 and 78 penetrate into the material of the wire and at the respective higher end of the separating edges 76, 78 the blank 62 is then completely separated from the wire. The blank 62 therefore does not have to be held by separate devices but is used as a free end of a wire into the in Fig. 6 Position shown between the two flat rolling jaws 72, 74 moves. If the flat rolling jaws 72, 74 then according to in Fig. 6 If the arrows shown are moved to the left or right, the blank 62 is already clamped between the flat rolling jaws 72, 74. After the blank 62 has been separated from the wire, the blank 62 is then held securely between the two flat rolling jaws 72, 74.

Fig. 7 shows a schematic, sectional plan view of a connecting element 80 according to the invention and an end section of a flat rolling jaw 72. The flat rolling jaw 72 is identical to the flat rolling jaw 16 of the Fig. 2 educated. In contrast to Fig. 3 However, the connecting element 80 according to the invention is made from a blank 62 without waste, cf. Fig. 5, Fig. 6 , manufactured. Specifically, the blank 62 is formed into the connecting element without the formation of slugs. For this purpose, the blank 62 can be used, as in the 5 and 6 is shown, for example cylindrical and designed as a section of a wire 66.

Fig. 8 shows schematically another connecting element 90 according to the invention Fig. 8 Lower spherical section 92 is designed to be more bulbous in the middle region than the upper spherical section. If the connecting element 90 is pressed directly into a through opening in a sheet metal 94, the areas marked with dashed lines are 96, which when pressed in according to the arrows in Fig. 8 are pressed in, enough material is available to anchor the spherical section 92 securely in the sheet 94.

Claims (8)

1. Method for producing a connecting element (40) having at least two spherical portions (54, 56), wherein two spherical portions (54, 56) are directly adjacent, or wherein two spherical portions are connected to one another by means of a connection portion, by rolling an integral blank (10), which is cylindrical at least in portions, between at least two rolling tools and shaping the at least two spherical portions (54, 56) and optionally the connection portion during rolling, characterized by holding the blank (10), at least prior to the beginning of rolling, on a feed head (14) of the blank (10), which is configured in the manner of a disc and in the radial direction protrudes beyond the blank (10), the latter, with the exception of the feed head (14), being cylindrical.
2. Method according to Claim 1, characterized in that the shaping takes place in the course of 10 to 15 revolutions of the blank (10).
3. Method according to Claim 1 or 2, characterized by severing in each case one item of scrap (44, 46) from the external ends of the spherical portions at the end of the rolling procedure by means of a cutting edge on a rolling tool that extends beyond the central longitudinal axis (42) of the connecting element (40).
4. Method according to Claim 3, characterized by severing the feed head (14) conjointly with severing one of the items of scrap (46).
5. Method according to at least one of the preceding claims, characterized in that the blank (10) has a circular-cylindrical main body (12).
6. Method according to at least one of the preceding claims, characterized in that two flat dies (16) are provided as rolling tools.
7. Method according to Claim 6, characterized in that each flat die (16) has two groove-shaped clearances (20, 22) which widen and deepen in the envisaged rolling direction.
8. Method according to Claim 7, characterized in that the two groove-shaped clearances (20, 22) are separated by means of a central web (24) running parallel to the envisaged rolling direction.

Images