EP3490755B1 - Tool for inserting and/or removing a wire thread insert - Google Patents

Description

1. Field of the invention

The present invention relates to a tool for installing or removing a wire thread insert and a manufacturing method therefor.

2. Background of the invention

Various tools for installing or removing wire thread inserts are known in the prior art. Such tools include a spindle body which usually has a drive portion and a threaded receiving portion for unscrewing the wire thread insert. An installation blade is arranged inside this spindle body. This installation blade is an elongated construction with a central pivot point. This central pivot point is also often the attachment point of the installation blade, which is formed by a pin riveted into the spindle body. At one end of the installation blade there is an attack end that engages the wire thread insert. A spring is often arranged at the other end of the installation blade so that the attack end is resiliently biased into an engagement position in the wire thread insert.

Such tools are in EP 0 153 266 , EP 0 153 267 , EP 0 153 268 B1 , EP 0 615 818 and DE 10 2011 051 846 B1 described.

In the above-mentioned prior art documents, an attack end of the installation blade engages the wire thread insert through a radial recess in the spindle body. For this purpose, the wire thread insert has a corresponding notch, for example. As soon as the tool for installing or removing the wire thread insert is rotated in the component opening, the torque of the tool is transmitted to the wire thread insert via the attack end of the installation blade. In order to ensure the stability of the attack end of the installation blade, the attack end is supported mostly on a radially arranged stop surface of the spindle body. The stop surface is spanned by a radial length section parallel to the radius of the spindle body and an axial length section parallel to the longitudinal axis of the spindle body.

It has been shown that these radially arranged stop surfaces are exposed to mechanical tension loads, in particular compressive forces on the stop surface, which exceed the mechanical stability of the material of the spindle body. These mechanical loads act mainly in a tangential direction in relation to the spindle body. This is due to the fact that when installing and / or removing a wire thread insert, the attack end strikes abruptly with the force of the acting torque against the stop surface. This recurring, almost cyclical load leads to material fatigue and material failure in the area of the radial recess, which disadvantageously shortens the service life of the tool and creates maintenance costs. For this reason, after a certain period of use of the tool, this mechanical stress leads to damage to the spindle body adjacent to the attack end of the installation blade.

It is therefore the object of the present invention to provide a tool with a longer service life and less wear compared to the prior art.

3. Summary of the Invention

The above object is achieved by a tool according to independent claim 1 and by a manufacturing method for this tool according to independent claim 8. Advantageous embodiments and further developments of the present invention emerge from the following description, the accompanying drawings and the appended claims.

The tool according to the invention for installing and / or removing a wire thread insert has the following features: a spindle body with a drive section and a receiving section for a wire thread insert, the receiving section comprising a thread for unscrewing or a threadless surface for attaching the wire thread insert, an installation blade, at least partially in the spindle body is arranged and which comprises an attack end with which the wire thread insert can be installed and / or removed by the installation blade, the spindle body having a radial recess in the receiving section in which the attack end of the installation blade is at least temporarily arranged and which has a curvilinear circumferential profile and / or comprises at least one relief notch for reducing mechanical stress in the spindle body.

As has already been discussed above, the radial recesses in the spindle body have an angular shape for penetration of the attack end of the installation blade. This is in the form of a window or an angular U-shaped cutout. It is precisely this angular shape of the radial recess that leads to mechanical stress peaks in the corner regions of the radial recess when the attack end is supported on the edges of the radial recess. These voltage peaks overload the material of the spindle body due to the mostly cyclical loading during use of the tool. These overload conditions cause the material of the spindle body to fail in the area of the radial recess, as a result of which crack growth, material breakouts and loss of strength are generated in the material of the spindle body. According to an alternative of the present invention, no angular contours are therefore used to design this radial recess. Instead, the radial recess has a curvilinear circumferential profile. This curvilinear circumference ensures that any mechanical stresses that occur are not concentrated in one point. Instead, these mechanical stresses that occur are distributed over the entire available edge of the radial recess, for example due to the support of the attack end on the edges of the radial recess. In this way, these existing mechanical stresses are transferred to the spindle body over a larger area and in this way avoid overload conditions in the material of the spindle body.

According to a further alternative of the present invention, at least one relief notch is provided in the radial recess of the spindle body. This relief notch also removes the angular course of the radial recess. The relief notch preferably extends transversely to the circumferential contour of the radial recess and preferably outside of stop surfaces. In this way, additional freedom of movement is provided precisely to the edge region of the radial recess, so that, for example, particularly stressed regions can yield to reduce mechanical stresses. Since stressed areas are not held in place by adjacent edge areas of the radial recess due to the relief notch, the radial edge area of the recess adjoining a relief notch uses the elastic material properties of the spindle body and relieves mechanical stresses. Since the material stress occurring here only uses the elastic material behavior and does not lead to plastic deformation, these mechanical stresses also do not cause a failure of the spindle body in the area of the radial recess.

According to a preferred embodiment of the present invention, the radial recess has at least one radially arranged stop surface on which the attack end of the installation blade can be supported when the spindle body rotates. According to a further preferred embodiment of the present invention, the contour of the radial recess outside of the at least one radial stop surface is arcuate. This preferred arcuate design is used to avoid corner areas in the radial recess, which can lead to a concentration of mechanical stresses.

According to a further preferred embodiment of the present invention, the at least one relief notch represents a depression in the circumferential course of the radial recess, which is arranged outside and preferably adjacent to the at least one stop surface.

Based on practical experience when using the installation and / or removal tool for wire thread inserts, it has been shown that the mechanical loads on the spindle body are limited to the at least one radial stop surface of the radial recess. In order to reduce the mechanical stresses occurring in this area, it is preferred to arrange the at least one relief notch adjacent to the radial stop surface. In this way, the radial stop surface is preferably provided with additional freedom of movement, since the spindle body can yield elastically in the area of the radial recess.

To relieve the radial recess, the relief notch preferably extends at least partially in the axial direction of the spindle body and has a straight or curvilinear shape. In this context, it is further preferred that the at least one relief notch is arcuate, the arcuate shape tapering off in a direction facing away from the at least one adjacent stop surface. It is precisely this preferred shape that is decisive for actually relieving mechanical stresses on the stop surface. In addition, with the aid of this shape and the preferred depth of the relief notch, the spring behavior of the radial recess, in particular the stop surfaces, as well as the mechanical stress curve within the spindle body are positively influenced, i.e. in the direction of stress reduction.

According to a further preferred embodiment of the present invention, at least one relief notch is provided for each stop surface of the radial recess.

The present invention also comprises a manufacturing method for a tool for installing and / or removing a wire thread insert, which has the following steps: manufacturing a spindle body with a drive section and a receiving section, the receiving section having a thread for turning on or a threadless surface for attaching the wire thread insert has, generating a radial recess within the receiving portion, which comprises a curvilinear circumferential profile and / or at least one relief notch for mechanical stress relief in the spindle body, providing and arranging an installation blade in the spindle body so that an attack end of the installation blade is at least temporarily arranged in the radial recess.

In a further embodiment of the manufacturing method according to the invention described above, it is preferred to provide the radial recess with at least one radially arranged stop surface. In addition, relief notches are preferably provided with an axial extension in relation to the spindle body, which have a straight or a curvilinear shape.

4. Brief description of the accompanying drawings

Figur 1

ein Werkzeug zum Ein- oder Ausbauen eines Drahtgewindeeinsatzes aus dem Stand der Technik mit einer radialen Ausnehmung,

Figur 2

eine schematische Darstellung eines Aufnahmeabschnitts eines aus dem Stand der Technik bekannten Werkzeugs,

Figur 3

eine schematische Darstellung des Aufnahmeabschnitts des Werkzeugs gemäß Fig. 1 aus dem Stand der Technik,

Figur 4

eine bevorzugte Ausfuhrungsform der radialen Ausnehmung gemäß vorliegen-der Erfindung,

Figur 5

eine weitere bevorzugte Ausfuhrungsform des erfindungsgemäßen Aufnahme-abschnitts des Werkzeugs,

Figur 6

eine weitere bevorzugte Ausführungsform des Aufnahmeabschnitts mit radialer Ausnehmung und Entlastungskerbe,

Figur 7

eine weitere bevorzugte Ausführungsform des Aufnahmeabschnitts mit radialer Ausnehmung und Entlastungskerbe,

Figur 8 a, b

weitere bevorzugte Ausführungsformen der Entlastungskerbe in der radialen Ausnehmung und

Figur 9

ein Flussdiagramm einer bevorzugten Ausführungsform des Herstellungsver-fahrens vorliegender Erfindung.

The preferred embodiments of the present invention will be explained in more detail with reference to the accompanying drawings. Show it:

Figure 1

a tool for installing or removing a wire thread insert from the prior art with a radial recess,

Figure 2

a schematic representation of a receiving section of a tool known from the prior art,

Figure 3

a schematic representation of the receiving portion of the tool according to FIG Fig. 1 from the state of the art,

Figure 4

a preferred embodiment of the radial recess according to the present invention,

Figure 5

a further preferred embodiment of the receiving section of the tool according to the invention,

Figure 6

another preferred embodiment of the receiving section with a radial recess and relief notch,

Figure 7

another preferred embodiment of the receiving section with a radial recess and relief notch,

Figure 8 a, b

further preferred embodiments of the relief notch in the radial recess and

Figure 9

a flow chart of a preferred embodiment of the manufacturing method of the present invention.

5. Detailed Description of the Preferred Embodiments

Various tools for installing and removing wire thread inserts are known in the art, as discussed above. Exemplary shows Fig. 1 such a tool 1. The tool 1 comprises a spindle body 10 which can be rotated automatically and / or manually via a drive section 5. Fig. 1 shows a preferred embodiment of a drive section 5 which can be fastened in a suitable chuck of a drive unit. For the manual rotation of the tool 1, a web or arm arranged transversely to the longitudinal axis L of the tool 1 is preferably provided (not shown). At an end opposite the drive section 5, the spindle body 10 has a receiving section 20 for the wire thread insert (not shown). The receiving section 20 is in the enlarged detail Fig. 1 to recognize.

The receiving section 20 comprises a thread 2 for screwing or unscrewing the wire thread insert or a threadless surface (not shown) for attaching the wire thread insert.

An axial recess (not shown) is usually provided within the spindle body 10, in which an installation blade, also not shown, is arranged. Such installation blades are known from the prior art, for example from DE 10 2011 051 846 B1 , EP 1 838 499 B1 , EP 0 153 267 B1 , EP 0 615 818 A1 and WO 2012/062604 .

The installation blade has an attack end 24, as illustrated in FIGS Figs. 2 and 3 is shown. The attack end 24 protrudes from the interior of the spindle body 10 into a radial recess 30 in the spindle body 10 or beyond to the outside. Depending on the construction of the tool 1 known from the prior art and the arrangement of the installation blade in the spindle body 10, the attack end 24 of the installation blade is arranged permanently or temporarily in the radial recess 30. The installation blade is selectively pivotable or tiltable or generally movable in the spindle body 10. Building on this, depending on the operating mode of the tool 1, the engagement end 24 is moved into the radial recess 30 in order to engage a wire thread insert. In the same way is the attack end 24 can be removed from the radial recess 30 into the interior of the spindle body 10. It follows from this that the attack end 24 is arranged at least partially in the radial recess 30.

According to different preferred embodiments of the present invention, the radial recess 30 has the shape of a window (see Fig. 2 ), so that it is limited circumferentially by the spindle body 10. According to a further preferred embodiment, the radial recess 30 is designed in a manner similar to a groove running in the axial direction in the spindle body 10 (see FIG Fig. 3 ). It is also preferred to represent the radial recess 30 (not shown) as an L-shaped surface if, for example, the tool is only used in one direction of rotation. In this case, the L-shaped radial recess 30 would only provide a stop surface 32 on one side. In general, the radial recess 30 represents an opening in the spindle body 10 in the radial direction, i.e. perpendicular to the longitudinal axis of the spindle body 10. This radial opening preferably has a certain width adapted to the size of the attack end 24 and a certain length parallel to the longitudinal axis L of the spindle body 10 on.

The spindle body 10 is rotated about its longitudinal axis L for installing and / or removing a wire thread insert, as in FIG Fig. 1-3 is indicated by the arrows D (direction of rotation). As soon as the engagement end 24 engages a wire thread insert during this rotary movement, the engagement end 24 is pressed against one of the oppositely arranged stop surfaces 32 of the radial recess 30 and is supported there. The radial recess 30 preferably comprises at least one stop surface 32. If the tool is only used for installing or only removing wire thread inserts, only one stop surface 32 in the screwing-in direction or in the screwing-out direction D is sufficient. If, on the other hand, the tool 1 is used for installing and removing wire thread inserts, two stop surfaces 32 arranged opposite one another are preferred.

A circumferential contour or a circumferential course 34 of the radial recess 30 is angular in known tools, as in FIG Fig. 1-3 can be seen. From this shape it follows that the stop surface 32 to support the attack end 24 when a or removing a wire thread insert is limited by two corner areas 36 in each case. These corner areas 36 generate mechanical stress peaks in the spindle body 10 during use of the tool 1.

According to a preferred embodiment of the present invention, the radial recess 30 is equipped with rounded portions 38 in order to reduce the mechanical stress peaks. The fillets 38 are arranged instead of the corner regions 36. These fillets 38 are not angular and have an arcuate ( Fig. 4 ) or curvilinear course. In this way, mechanical loads on the stop surfaces 32 are diverted into the spindle body 10 without generating stress peaks. It is also preferred to design the fillets 38 in the shape of a bone. Such roundings 38 are both in a receiving section 20 with (see Fig. 5 ) or without thread 22 (see Fig. 4 ) as well as in an extensively closed one (see Fig. 4 ) or in a radial recess 30 open on one side (see Fig. 5 ) usable.

According to a further preferred embodiment of the present invention, the radial recess 30 of the receiving section 20 has at least one relief notch 40. Different preferred configurations of the relief notch 40 are shown in FIGS Figures 6 and 7 shown. The shape of the relief notch 40 is not limited to the preferred embodiments shown. The relief notch 40 is explained below using the example of a groove-shaped radial recess 30 and applies in the same way to a radial recess 30 with a closed circumferential contour 34.

The relief notch 40 is preferably arranged adjacent to a stop surface 32 in order to support the reduction and dissipation of the mechanical stresses occurring there into the material of the spindle body 10. The relief notch 40 thus preferably forms a depression in and perpendicular to the circumferential profile 34 of the radial recess 30.

Furthermore, the at least one relief notch 40 is preferably arranged instead of a corner region 36. In this way, through the relief notch 40, the rigid connection between the stop surface 32 and a transverse surface 33 of the radial recess 30 is released in order to give the stop surface 32 additional flexibility or freedom of movement within the framework of the To give properties of the material of the spindle body 10. The relief notch 40 thus preferably allows additional yielding of the stop surface 32 in relation to the mechanical loads from the attack end 24. In this way, mechanical stress peaks from the stop surface 32 into the axial depth of the spindle body 10, i.e. towards the closed end of the relief notch 40, relocated.

In order to support the spindle body 10 in its stability, a material in combination with a hardness specification with reference to optimal crack insensitivity with low plastic deformation and good wear resistance is preferred. According to a preferred embodiment of the present invention, a precipitation hardening steel with the identifier 1.2709ESU with a preferred hardness in the range from 50 to 58 HRC, preferably 54 HRC, is used. It is also preferred to age martensitic steel according to 1.2550. 1.2767 ESU with 52 HRC to be used. Alternatively, hard metal is also preferably used as the spindle body material, which has received its material properties based on coordinated sintering processes.

At least one relief notch 40 is preferably arranged adjacent to each stop surface 32 or only adjacent to a selected stop surface 32. It is further preferred that a relief notch 40 is provided instead of each corner area 36 or only instead of selected corner areas 36. It is therefore preferred to equip the closed radial recess 30 with one or two relief notches 40 per stop surface 32. It is also preferred to equip the open, groove-shaped radial recess 30 with a relief notch 40 per stop surface 32.

The relief notch 40 preferably runs with at least part of its length in the axial direction of the spindle body 10. This course is straight or curvilinear or represents a combination of sections of both course shapes. It is also preferred to merge an initially straight axial course into an arcuate section allow. It has proven to be advantageous if one end of the arch shape faces away from the stop surface 32 (see FIG Figures 6 and 7 ).

Based on the comparison of the Figures 6 and 7 it can also be seen that the relief notch 40 is preferably a j-like shape (see FIG Fig. 6 ) or a comma-like form (see Fig. 7 ) having.

Regardless of the shape of the relief notch 40, the preferred embodiments of the present invention have shown that with increasing depth T of the relief notch 40 in the axial direction of the spindle body 10, the mechanical load on the relief notch 40 and thus the material of the spindle body 10 is reduced. This is based on the exemplary voltage values of the Figures 6 and 7 recognizable. At a depth T of approx. One thread turn in Fig. 6 a mechanical stress reduction to 420 MPa is achieved. At a depth T of approx. 1.5 threads in Fig. 7 a mechanical stress reduction to approx. 340 MPa is achieved. Thus, it is preferable to provide the relief notch 40 with as great a depth as possible. This depth T preferably has a value from the range of 0.5 ST T 4 ST, more preferably 1.0 ST T 3.5 ST and in particular T = 1.5 ST, where ST denotes the pitch of the thread of the spindle body. Preferably, the relief notch 40 begins at the root of the thread and ends at the tip of the thread. The relief notch 40 has a preferred width B _K in the circumferential direction of the spindle body 10 in the range of 0.15 mm B _K 0.5 mm, preferably B _K = 0.3 mm.

Figure 8a, b shows by way of example further preferred courses of relief notches 40. The relief notch 40 of FIG Figure 8 a in a curvilinear course to a depth of T = 3.5 · ST. A smaller depth is also preferred here if the mechanical loads on the stop surface 32 permit this. Figure 8b shows a preferred relief notch 40 which is inclined in the direction of the stop surface 32.

For the preferred production of the tool 1 (see Figure 9 ) The spindle body 10 with the drive section 5 and the receiving section 20 is first produced in step S1. Subsequently, in step S2, the radial recess 30 is produced within the receiving section 20. The radial recess 30 then has at least one of the preferred shape features described above for mechanical stress relief.

In a further preferred method step S3, the spindle body 10 with radial recess 30 and relief notch 40 or rounding 38 is irradiated with a blasting agent. The abrasive is preferably accelerated by means of compressed air and applied to the outer Surface of the spindle body 10 directed. In this way, body edges of the spindle body 10 are preferably rounded and / or the surface of the spindle body 10 is compressed. Both abrasive and non-abrasive media are suitable as blasting media. Exemplary blasting media are sand, slag blasting media, corundum, plastic and / or chilled cast iron or cast steel. With preferred glass beads, a slight plastic deformation of the surface of the spindle body 10 is achieved. This preferably leads to an internal stress in the spindle body 10, as a result of which the surface hardness and the fatigue strength are increased.

Finally, the installation blade is provided in step S4 and arranged in the spindle body 10 in step S4 in such a way that the attack end 24 of the installation blade is arranged in the radial recess 30. Furthermore, at least one of the radial stop surfaces 32 is preferably provided in the radial recess 30 in the context of the production method. In addition, it is preferred to provide the relief notch 40 discussed above with an axial extension relative to the spindle body 10 in such a way that it has a straight or a curvilinear shape.

List of reference symbols

1

Tool

5

Drive section

10

Spindle body

20th

Receiving section

22nd

thread

24

End of attack

30th

radial recess

32

Stop surface

33

Transverse surface

34

Perimeter contour

36

Corner area

38

Rounding

40

Relief notch

L.

Longitudinal axis

D.

Direction of rotation

ST

Pitch of the thread of the spindle body

BK

Width of the relief notch

Claims (11)

1. A tool (1) for installing and/or removing a wire thread insert that has the following features:

   a. a spindle body (10) with a drive section (5) and a seat section (20) for a wire thread insert, wherein the seat section (20) comprises a thread (22) for screwing on, or a threadless surface for plugging on, the wire thread insert,

   b. an installation blade that is at least partially arranged in the spindle body (10) and that comprises a contacting end (24) with which the wire thread insert can be installed and/or removed by the installation blade, wherein

   c. the spindle body (10) has a radial recess (30) in the seat section (20) in which the contacting end (24) of the installation blade is at least temporarily arranged, characterized in that

   d. the radial recess (30) has a curvilinear peripheral contour (34, 38) and/or at least one release notch (40) for mechanically decreasing the stress in the spindle body (10).
2. The tool (1) according to claim 1, wherein the radial recess (30) has at least one radially arranged stop face (32) against which the contacting end (24) is abutable when the spindle body (10) is turned.
3. The tool (1) according to claim 2, wherein the peripheral contour (38) of the radial recess (30) is formed in an arc outside of the at least one radial stop face (32).
4. The tool (1) according to claim 2, wherein the at least one release notch (40) represents a depression in the peripheral contour (34) of the radial recess (30) that is arranged outside of the at least one stop face (32).
5. The tool (1) according to one of the preceding claims, wherein the release notch (40) extends at least partially in the axial direction of the spindle body (10) and has a straight and/or curvilinear shape.
6. The tool (1) according to one of the preceding claims 1 to 4, wherein the release notch (40) extends at least partially in the axial direction of the spindle body (10) and is formed in an arc, wherein in one direction, the arc runs away from the at least one adjacent stop face (32).
7. The tool (1) according to one of the preceding claims, wherein at least one release notch (40) is provided for each stop face (32).
8. A production method for a tool (1) for installing and/or removing a wire thread insert that has the following steps:

   a. producing (S1) a spindle body (10) with a drive section (5) and a seat section (20), wherein the seat section (20) has a thread (22) for screwing on, or a threadless surface for plugging on, the wire thread insert, characterized by the further steps:

   b. creating (S2) a radial recess (30) within the seat section (20), that comprises a curvilinear peripheral contour and/or at least one release notch (40) for decreasing the mechanical stress in the spindle body (10),

   c. providing (S3) and arranging (S4) an installation blade in the spindle body (10) so that a contacting end (24) of the installation blade is at least temporarily arranged in the radial recess (30).
9. The production method according to claim 8, wherein the radial recess (30) is provided with at least one radially arranged stop face (32).
10. The production method according to claim 8 or 9, wherein the release notch (40) is provided with an axial extension relative to the spindle body (10) that has a straight or curvilinear shape.
11. The production method according to claim 8, with the further step (S3):
    Blasting the spindle body with an abrasive and/or nonabrasive blasting medium to improve the lifetime of the spindle body (10).

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