EP0613410B1 - Non-cutting tool for producing inner profiles - Google Patents

Abstract

A non-cutting tool is disclosed for producing workpiece inner and outer profiles, in particular inner and outer threads. The tool has several elements (1) arranged in such a way in their initial position that they may be inserted into the workpiece. In addition, a spreading element (3) is provided that moves the tool elements (1) in a direction essentially perpendicular to the surface or in a radial direction into an engagement position, in which the tool elements (1) are pressed on the workpiece (6) in such a way that no gaps are left between them and the desired profile is formed.

Description

Technical field

The invention relates to a tool for the non-cutting production of internal contours on workpieces and in particular internal threads.

State of the art

Internal threads are currently essentially rolled, pressed, cut or cast.

The thread rolling is mainly suitable for solid workpieces, whereby it results in a high work hardening and an uninterrupted fiber flow with a short processing time.

Threading is essentially suitable for thin-walled, rotationally symmetrical parts, preferably made of aluminum. With two profiled rollers, one of which is arranged in a fixed position and the other is adjustable, the thread is created by pushing the thin-walled part between the rollers. However, the part must rotate.

Tapping is only suitable if the material thickness is sufficient and produces an interrupted fiber course with a long machining time.

Ultimately, casting a thread is very complex; nevertheless there is often insufficient accuracy with a very long processing time.

From DE 32 00 755 Al a tool for the non-cutting production of internal threads is known. This known tool has two segments which are arranged in a basic state such that they can be inserted into the tubular workpiece. A spreading element moves the segments by moving in a radial direction into an engagement state in which the segments are pressed onto the tubular component in such a way that they (partially) form the thread.

However, this known generic tool has the disadvantage that it cannot be used to easily produce technically usable internal threads:

In particular, this tool does not provide a complete thread if it is not rotated and moved during use, as there are gaps between the segments. This means that no screw can be screwed into the internal thread produced with this tool without additional machining processes.

It is consequently stated in DE 32 00 755 A1 that a further tool is used for embossing a complete thread, which tool is rotated by approximately 90 ° and is additionally displaced linearly by a quarter pitch. This not only increases the manufacturing effort, but can also lead to manufacturing errors. The wear on the tool is also increased.

It is for this reason that the tool known from DE 32 00 755 A1 has no further significance.

Furthermore, DE 39 33 292 shows a spreading tool for a shaping device for producing hollow workpieces with a desired inner contour. The tool essentially has a three-part construction, which is composed of an inner punch 8, a molding ring 4 which carries out the pressing process and the molding segments 11 and 12 provided within an expansion sleeve.

For the shaping of a workpiece, this is applied to a workpiece carrier, which positions the workpiece relative to the mold segments that form a seamless inner contour within the workpiece. Furthermore, in order to maintain the inner, closed contour, a stamp is inserted into the spreading tool, which, by means of appropriate counterpressure, leaves the mold segments in their closed contour against an external force. The pressing process itself is effected by lowering the form ring 4 so that the material of the workpiece is pressed against the contour of the segments from the outside. It is essential here that the flow of force acts on the workpiece from the outside. The material of the workpiece is thus pressed onto the outer contour of the segment shape which is apparent in the interior of the workpiece. A desired deformation of the inner contour can thus be obtained if, in addition to the inner deformation, the outer contour of the workpiece is also deformed.

Presentation of the invention

The invention has for its object a tool for the non-cutting production of inner contours To specify workpieces and in particular internal threads, which allows the production of, for example, "self-contained", ie all-round contours and in particular of threads with high accuracy and surface quality with a short machining time, without the tool being quickly worn out. Furthermore, inner contours in workpieces should be shaped in this way without changing the outer contour of the workpiece itself. In addition, the tool according to the invention should, if appropriate, make it possible to carry out cutting or separating processes.

This object is achieved according to the invention for the production of inner contours by the features of claim 1. Developments of the invention are the subject of the dependent claims.

At least three tool elements are provided, which are arranged in the engaged state in such a way that they connect to one another without a gap.

Here, of course, the tool elements are provided on their engagement surface with a contour that is complementary to the desired inner contour.

The contour of the respective engagement surfaces does not necessarily have to be designed such that a thread is produced. Rather, the tool elements can be provided with a different (even non-uniform) shape instead of a thread, so that any internal contours can be created. If required, these contours can result in a closed circle (360 °).

Of course, it is also possible, according to claim 9, for the individual tool elements to be provided with different contours on their engagement surface. This makes it possible, for example, to introduce a thread only over a part of the circumference and to push back the material of the workpiece in the part of the circumference into which no thread is to be introduced "behind the thread base".

In any case, very thin-walled, cold-formable materials can be processed without separating the fiber course and a large strain hardening. It is also possible to incorporate sealing surfaces or to calibrate sealing surfaces that have already been created or to protect them from possible damage. The elements can also perform not only a linear movement, but also a movement composed of several linear movements. The tool according to the invention does not require any rotating tool elements or counterholders, i.e. simple requirements are placed on the drives.

In this way, threads can be produced with simple tools using a tool designed according to the invention, the tool life being long.

In the following claims 12 implementations of the basic idea according to the invention are described which enable the cutting of tubular workpieces or workpieces with any cross section from the inside to the outside without reshaping the tube. In addition, these realizations enable the non-cutting production of internal contours on workpieces that are created have freely selectable shapes in cross-section, that is to say, for example, as rectangular profiles, or oval, or as contours composed of individual curve parts.

Ultimately, in addition to forming work, the complete or partial cutting or cutting of workpieces or the introduction of openings in the wall of the workpiece can also be realized.

The tool according to the invention for the non-cutting production of internal contours on workpiece recesses with a free cross section or for carrying out cutting work of such workpieces has, from the inside out, a plurality of tool elements which are arranged in the basic state in such a way that they can be inserted into the recess of the workpiece. By means of a movement essentially perpendicular to the surface of the workpiece, an expansion element converts the tool elements into an engagement state in which the workpiece elements are pressed against the workpiece walls in such a way that they form the desired contour or carry out cutting, notching or perforating work.

According to the invention, the tool elements are arranged in the engaged state in such a way that they connect to one another without space for the cutting or shearing process (segmentation) of the workpiece.

The number of tool elements is determined by the respective cross section of the workpiece. For triangular and rectangular profiles of the workpiece, the number of sides or corners of the polygon corresponds to the number of required leading and trailing tool elements. For example, if the workpiece has a rectangular profile, four leading and four lagging tool elements are required.

The complete separation on the circumference of the workpiece (segmentation) or the creation of openings, perforations, notches, etc. can also be done with non-metallic materials, e.g. Cardboard tubes, plastic parts or profiles, etc. carry out.

Brief description of the drawing

Fig. 1a

einen Längsschnitt, und

Fig. 1b und 1c

einen Querschnitt durch ein erstes Ausführungsbeispiel,

Fig. 2a bis 2c

entsprechende Darstellungen für eine Variante des ersten Ausführungsbeispiels,

Fig. 3a bis 3d

entsprechende Darstellung für eine weitere Variante des ersten Ausführungsbeispiels,

Fig. 4

einen Querschnitt durch ein zweites Ausführungsbeispiel,

Fig. 5a

einen Längsschnitt, und

Fig. 5b und 5c

einen Querschnitt durch ein drittes Ausführungsbeispiel,

Fig. 6

ein Werkzeug mit der zusätzlichen Möglichkeit der Herstellung von Dichtflächen, und

Fig. 7a

einen Längsschnitt, und

Fig. 7b und 7c

einen Querschnitt durch eine Anordnung zum Schneiden bzw. Abscheren von Rechteckhohlprofilen.

The invention is described below by way of example without limitation of the general inventive concept on the basis of exemplary embodiments with reference to the drawing, to which reference is expressly made with regard to the disclosure of all details according to the invention not explained in detail in the text. Show it:

Fig. 1a

a longitudinal section, and

1b and 1c

3 shows a cross section through a first exemplary embodiment,

2a to 2c

corresponding representations for a variant of the first exemplary embodiment,

3a to 3d

corresponding representation for a further variant of the first exemplary embodiment,

Fig. 4

3 shows a cross section through a second exemplary embodiment,

Fig. 5a

a longitudinal section, and

5b and 5c

3 shows a cross section through a third exemplary embodiment,

Fig. 6

a tool with the additional possibility of producing sealing surfaces, and

Fig. 7a

a longitudinal section, and

7b and 7c

a cross section through an arrangement for cutting or shearing of rectangular hollow sections.

Representation of exemplary embodiments

The invention is described below using tools for producing internal threads.

• 1 Werkzeugelement(e)
  • 1.1 voreilendes Werkzeugelement
  • 1.2 nacheilendes Werkzeugelement
• 2 Führungsplatte(n)
  • 2.1 keilförmige Hilfselemente
• 3 Keil/Konus
• 4 Rückführelement
• 5 Gegenhalter (teilbar)
• 6 zu bearbeitende Werkstück
• 7 Element zum Formen/Erhalten einer Dichtlippe

bezeichnet, so daß auf eine erneute Vorstellung verzichtet wird, und lediglich die Abweichungen der in diesen Figuren dargestellten Ausführungsbeispiele gegenüber dem ersten Ausführungsbeispiel erläutert werden:
Fig. 1 zeigt ein erstes Ausführungsbeispiel der Erfindung, das vier vorauseilende Werkzeugelemente (Hauptelemente) 1.1 mit einer Gewindestruktur auf der Außenfläche und vier (Nebenelemente) 1.2 aufweist, die ebenfalls mit einer Gewindestruktur versehen sind. Die Werkzeugelemente 1.1 und 1.2 haben jeweils die Form von Kreissegmenten. Die Hauptelemente 1.1 sind durch eine Deckel- und Bodenplatte 2 mit Stiften und Langlöchern in den Hauptelementen oder durch sonstige geeignete Führungssysteme geführt. Die Nebenelemente 1.2 sind durch ineinandergreifende Führungen mit den Hauptelementen 1.3 und einem Außenkonus 3 verbunden, so daß eine Zwangsrückführung entsteht. Ferner sind ein teilbarer Außenring 5 mit oder ohne Gewindestruktur sowie ein kreuzförmiger Ausfahrkonus 3 mit oder ohne ineinandergreifende Führungen für die Nebenelemente 1.2 vorgesehen.Furthermore, the same or corresponding parts with the following reference numerals are in the following figures:

• 1 tool element (s)
  • 1.1 leading tool element
  • 1.2 lagging tool element
• 2 guide plate (s)
  • 2.1 wedge-shaped auxiliary elements
• 3 wedge / cone
• 4 feedback element
• 5 counterholders (divisible)
• 6 workpiece to be machined
• 7 Element for forming / maintaining a sealing lip

referred to, so that a new presentation is dispensed with, and only the deviations of the exemplary embodiments illustrated in these figures from the first exemplary embodiment are explained:
Fig. 1 shows a first embodiment of the invention, the four leading tool elements (main elements) 1.1 with a threaded structure on the outer surface and four (secondary elements) 1.2, which are also provided with a threaded structure. The tool elements 1.1 and 1.2 each have the shape of circular segments. The main elements 1.1 are guided by a cover and base plate 2 with pins and elongated holes in the main elements or by other suitable guide systems. The secondary elements 1.2 are connected by interlocking guides with the main elements 1.3 and an outer cone 3, so that a forced return occurs. Furthermore, a separable outer ring 5 with or without a threaded structure and a cruciform extension cone 3 with or without interlocking guides for the secondary elements 1.2 are provided.

The functionality of this tool is explained below:
First, the outer ring 5 is placed on a preformed cylindrical section of a workpiece 6. (Fig. 1b). By pushing in the extension cone 3, the main elements 1.1 are pushed out by the secondary elements 1.2 and produce the thread (FIG. 1c). By returning the cone 3, the elements 1.1 and 1.2 are reset (Fig. 1b). Finally, the tool is extended and the outer ring 5 is removed.

A completely circumferential thread can thus be created by appropriately designing the main and secondary elements. The elements are designed that, starting from an initial position (diameter smaller than thread core diameter), they reach an end position in which they produce a complete thread, ie an end position in which there are no gaps between the individual segments in the extended state.

2a to 2c show Fig. 1 corresponding representations for a variant of the first embodiment, which differs from the example shown in Fig. 1 in that instead of four tool elements (main elements) 1.1 with a threaded structure on the outer surface and four trailing Tool elements (secondary elements) 1.2 there are three elements each. Accordingly, a hexagonal extension cone 3 is provided.

The further training and the mode of operation correspond to the first embodiment.

3a shows a longitudinal section through a further variant of the first exemplary embodiment; FIGS. 3a to 3d show corresponding cross sections, FIG. 3d showing a modification of the design shown in FIGS. 3b and 3c. In this exemplary embodiment, three main and secondary elements 1.1 and 1.2 are moved linearly outward from a basic state and produce a completely circumferential thread (FIG. 3c). An “intermediate step” is shown in FIG. 3b. For further details, reference is made to the drawing.

Fig. 4 shows a second embodiment in which two main elements formed as circular sections 1.1 rotatably supported on one side and moved outwards on circular paths by a secondary element 1.2. The process can also be viewed as a spreading process between two "jaws".

5 shows a third exemplary embodiment, in which a thread contour is provided only on every second segment. The segments without a thread contour are "advanced" over the outer contour of the segments with a thread contour, so that the material of the workpiece is pushed back "behind the thread base" in the part of the circumference into which no thread is to be introduced (FIG. 5c).

FIG. 6 shows an exemplary embodiment in which a sealing surface can be produced by a corresponding design of the tool elements in the area of the thread. A sealing surface is to be provided if a closure means with a sealing function is to be introduced into the thread to be produced. This sealing surface can be produced both in the case of external and internal threads by the tool elements and / or additional shape-supporting or shape-generating auxiliary elements 7.
If undercuts are created when creating the sealing surface, separable counterholders 5 must be used.

Instead of extending the tool elements by means of a cone-shaped mandrel, which is moved perpendicular to the extending movement of the tool elements, as is used in the exemplary embodiment described, other extension mechanisms can of course also be used:

Extension cam

Here, an eccentrically mounted circular disc or a cam disc is rotated and thus leads the tool elements to the outside. The cam can also be designed in a special curve shape in order to enable targeted shaping or the application of force.

Lever mechanism

The tool elements can also be extended by a lever mechanism, e.g. Articulated lever principle. This results in a forced return.

Exit wedge

The tool elements are e.g. radial movement of a wedge extended.

In the exemplary embodiments described above, external guidance of the tool elements has been used as the guide system. Here, the tool elements are guided through a plate arranged below or above or plates 2 arranged on both sides with integrated linear guide elements. Rails of various shapes as well as ball or pin guides can be used as guide elements.

An internal tool guide can of course also be used. Here linear guide elements are integrated into the tool elements. The guide elements can be designed as plates with guide rails in various shapes or as pin guides.

Radial or axial bearings can also be used. Such bearings are used especially in lever systems used and replace the linear guide elements.

• Blattfeder
• Zugfeder
• Druckfeder

welche auf jedes Element einzeln wirken, eingesetzt werden. Die zweite Möglichkeit der Federrückstellung kann als elastisches Band ausgebildet sein (z.B. Spiralfeder), welches auf alle beteiligten Werkzeugelemente gleichzeitig wirkt.Spring resets 4 can in particular be used as the resetting mechanism for tool elements. Here, springs in various forms, such as

• Leaf spring
• Tension spring
• Compression spring

which act individually on each element. The second possibility of spring return can be designed as an elastic band (eg spiral spring), which acts on all tool elements involved at the same time.

The forced return can be generated by a lever mechanism, which causes the tool elements to be extended and retracted. Another possibility of the forced reset can be done by interlocking guide systems both in the tool elements and in an extension cone or wedge. As a result, the tool elements are forcibly retracted during the return stroke of the extension cone.

7 shows an exemplary embodiment of a tool for carrying out complete separating processes (segmentation) from the inside to the outside.

The tool is inserted into the hollow profile.

The leading tool elements 1.1 (main elements) virtually span the four corners of the workpiece with a rectangular hollow profile. Due to the trailing tool elements 1.2 (secondary elements) in the extended state, the cutting edge of the cutting tool is closed along the circumference of the rectangular profile of the recess.

The tool elements 1.2 are retracted and extended by means of a cross-shaped extension cone 3 as a spreading element.

The tool elements 1.1 are guided through a cover and base plate 2 with pins and elongated holes in the tool elements or through other suitable guide systems. The secondary elements 1.2 are connected by interlocking guides with the main elements and the outer cone 3, so that a forced forward or return occurs.

Claims (18)

1. Device for producing inner profiles in a non-cutting operation, in a recess of a workpiece, particularly for producing internal threads,
      comprising several tool elements for forming the inner profile of said workpiece, which, in an initial state, are disposed so as to permit their introduction into said workpiece (6), and which arrive in an interlocked state, by a radial displacement against said recess of said workpiece, so as to join each other continuously,
      characterized in that a spreading element (3) is provided which is adapted to be centrally introduced between said tool elements in a direction orthogonal to the sense of displacement of said tool elements, and presses the latter, in the course of such introduction of said spreading element, whose outside periphery increases, against the recess of said tool by an enforced guiding action and with application of force, resulting in a deformation of the internal profile of said workpiece when the interlocked state is achieved.
2. Device according to Claim 1,
   characterized in that at least three tool elements are provided.
3. Device according to Claim 1,
   characterized in that said tool comprises at least two leading tool elements (1.1) and two trailing tool elements (1.2) which, in an initial state, are disposed within the outside profile of said leading tool elements.
4. Device according to any of Claims 1 to 3,
   characterized in that said spreading element comprises an extending mechanism and a guide for said tool elements.
5. Device according to Claim 4,
   characterized in that said extending mechanism is an extending cam, a lever mechanism, or an extending wedge or cone, respectively.
6. Device according to Claim 4 or 5,
   characterized in that said guide is an internal guide which permits a linear movement or a composite movement composed of several linear movements.
7. Device according to Claim 4 or 5,
   characterized in that said guide includes radial ball bearings or thrust bearings.
8. Device according to any of Claims 1 to 7,
   characterized in that said spreading element includes a resetting mechanism.
9. Device according to any of Claims 1 to 8,
   characterized in that said tool elements have different profiles on their engaging surfaces.
10. Device according to any of Claims 1 to 9,
    characterized in that said tool with interlocking tool elements is adapted for use also as tool support for subsequent machining operations.
11. Device according to any of Claims 1 to 10,
    characterized in that a counter-element (5) may be used in machining thin-walled parts of workpieces (6).
12. Device according to Claim 1,
    characterized in that said tool elements (1) comprise cutting edges which, in the interlocked state, are arranged so as to join each other continuously.
13. Device according to Claim 12,
    characterized in that the number of tool elements is determined by the respective polygonal cross-section, with the number of sides or corners, respectively, of the polygon corresponding to the respective number of said leading tool elements (1.1) as well as of said trailing tool elements (1.2) for triangular and rectangular profiles of said workpiece.
14. Device according to Claim 12 or 13,
    characterized in that it is applicable for cutting, for producing breakthroughs, perforations, grooves and notches, etc., even in non-metal materials such as cardboard tubes or plastic profiles.
15. Device according to Claim 12,
    characterized in that it is applicable for the operation of joining specifically shaped tube/hub joints, e.g. by release of straps, followers or similar elements engaging in the hub so as to create a positive connection.
16. Device according to Claim 12,
    characterized in that it creates the desired inner profile both by means of said tool elements and by the axially introduced spreading element configured in correspondence with the inner profile.
17. Device according to Claim 12,
    characterized in that said tool elements are extended by cam plates by means of a rotating movement.
18. Device according to Claim 12,
    characterized in that it is applicable as a tool combination for enlarging and subsequently extending additional tool segments.

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