Repair method for a cutting tool assembly

Abstract

The invention relates to a method for repairing a cutting tool assembly (10) comprising a main part (12) which is secured to a soil-working device and comprises a tool receiving area and a cutting tool (20) that can be secured in the tool receiving area in a replaceable manner. The tool receiving area comprises at least one body-side holding section which forms a form-fitting connection with a tool-side holding section of the cutting tool (20) transversely to a plug-in direction of the cutting tool (20) in the connected state. The method has the steps of: i) applying material onto the at least one body-side holding section such that the width of the tool receiving area is reduced in the region of the at least one body-side holding section transversely to the plug-in direction and ii) removing part of the previously applied material in order to enlarge the tool receiving area in the region of the at least one body-side holding section transversely to the plug-in direction up to a defined width.

Description

[0001] Repair procedure for a cutting tool assembly

[0002] The present invention relates to a method for repairing a cutting tool assembly according to claim 1.

[0003] A number of soil tillage machines use cutting tools to remove and / or crush soil material. One example is trench cutters, which have several counter-rotating cutting wheels with a multitude of cutting teeth arranged on their outer circumferential surfaces to remove and crush soil material in the trench.

[0004] Due to the high forces to which the cutting tools are exposed, significant wear occurs. The cutting tools are therefore typically designed as replaceable wearing parts that can be mounted in special cutting tool holders. For example, in trench wall cutters, it is common practice to weld base bodies with tool holders firmly to the outer circumferential surfaces of the cutting wheels and to lock the cutting tools in the tool holders using locking pins or dowel pins. This allows the cutting tools to be replaced without having to separate the entire cutting tool assembly from the cutting wheel and re-weld it each time. However, due to the high forces acting on the cutting tools, the base bodies or tool holders deform over time.Due to the special cutting tool geometry, the lateral contact areas between the cutting tool and the base body within the tool holder can be so severely deformed that the cutting tools are no longer firmly seated in the tool holder, but instead exhibit a certain amount of play. As a result, increasingly strong forces act on the locking pins during operation, until they are ultimately damaged or even destroyed. The consequence is that if the locking pin breaks, the cutting tool is no longer locked to the base body and falls out of the cutting tool holder.

[0005] Previously, the entire base body had to be separated from the milling wheel, for example by flame cutting, because the tool holder was no longer suitable for securely holding cutting tools. After separating the base body, the milling wheel had to be specially prepared at this point (e.g., by grinding) so that a new base body could be welded on. The new base body also required special preparation for this purpose (e.g., grinding / preparing edges) and had to be laboriously positioned at the correct angle on the milling wheel and then welded on. This process is not only complex, but can also lead to stresses and deformations in the milling wheel due to the high temperatures involved during welding.

[0006] The present invention is therefore based on the object of providing a simpler and more gentle repair method for cutting tools.

[0007] According to the invention, this object is achieved by methods having the features of claim 1. Advantageous embodiments of the invention emerge from the subclaims and the following description.

[0008] Accordingly, a method for repairing a cutting tool assembly is proposed, wherein the cutting tool assembly comprises a base body secured to a soil cultivation device (e.g., a cutting wheel of a trench cutter) with a tool holder, and a cutting tool that can be replaceably secured in the tool holder. The base body is firmly connected to the soil cultivation device and does not need to be separated or removed for repair. The cutting tool is designed as a replaceable wear part and can comprise a cutting blade or a cutting tooth.

[0009] The tool holder, into which the cutting tool can be inserted, comprises at least one body-side holding section, which, when connected, forms a positive connection transverse to an insertion direction of the cutting tool with a corresponding tool-side holding section of the cutting tool. In the case of a milling wheel, the insertion direction of the cutting tool runs in particular radially to the milling wheel.

[0010] The method according to the invention comprises the following steps:

[0011] First, material is applied to the at least one body-side holding section. This is in particular an area that has deformed so much due to advanced wear that the cutting tool can no longer be held securely or at least has a certain amount of play within the tool holder. By deliberately applying additional material to the at least one body-side holding section, the width of the tool holder transversely to the insertion direction is reduced in the area of ​​the holding section. Preferably, so much material is applied or the width of the tool holder is intentionally reduced in this area so far that the width is subsequently smaller than the width of the cutting tool transversely to the insertion direction.

[0012] In a subsequent step, a portion of the previously applied material is then selectively removed in order to enlarge the tool holder in the region of the at least one body-side holding section transversely to the insertion direction to a defined width. The defined width preferably corresponds to a standard width of the tool holder, which is provided for a secure and stable (i.e., in particular, largely play-free) reception of the cutting tool. Through the process of targeted application and removal of material in the tool holder, its width is in particular reset to its original state without the base body having to be replaced. Welding to the soil cultivation device (e.g., a cutting wheel) is not necessary, so that no harmful temperature effects occur. Furthermore, the repair method according to the invention allows for quick and efficient use in the field (i.e.,directly on site on the tillage implement), thereby reducing tillage implement downtime.

[0013] In one possible embodiment, the material is applied to the at least one body-side holding section by deposition welding, wherein the applied material preferably has the same or higher strength than the material of the at least one body-side holding section. The use of a high-strength material (in particular metal) that is stronger than the base material of the base body is preferred.

[0014] In a further possible embodiment, the width of the tool holder in the region of at least one body-side holding section is measured transversely to the insertion direction using a measuring device in order to reduce the width to a defined value by selectively removing previously applied material. This makes it possible to precisely determine when the tool holder has reached a desired width during the material removal process, and the removal can be stopped accordingly. The measuring device can also be used during the material application to determine when enough material has been applied and the width of the tool holder has reduced to a certain width.

[0015] In a further possible embodiment, the measuring device comprises a first contact element, a second contact element that can be moved relative to the first contact element, and a detection device for measuring the distance between the two contact elements. The second contact element can preferably be moved manually by the operator, so that the measuring device is easy to handle. The contact elements are designed to make contact from the inside with the at least one body-side holding section and with an opposite side section of the tool holder (which can also have a body-side holding section). The distance between the two contact elements of the measuring device is therefore a measure of the distance between the at least one body-side holding section and the opposite side of the tool holder and thus of the width of the tool holder.

[0016] Due to the simple design of the measuring device, which is particularly mobile, i.e. portable, the width of the tool holder can be easily and quickly remeasured during removal (and possibly also during application).

[0017] In another possible embodiment, the at least one body-side holding section is formed integrally with the base body. This gives the base body a compact and stable structure.

[0018] In another possible embodiment, the at least one body-side holding section has a profile that deviates from a flat shape transverse to the insertion direction of the cutting tool. The side of the tool holder facing the cutting tool in the area of ​​the body-side holding section is therefore not flat, but rather has a defined profile. Preferably, the profile tapers toward the center of the tool holder.

[0019] The aforementioned measuring device can be adapted to the profile of the holding section in order to achieve a more precise measurement of the width of the tool holder. In particular, one or both contact elements of the measuring device can have a profile complementary to the profile of the holding section. The profile of the contact element(s) can substantially correspond to a profile of a tool-side holding section of the cutting tool. The profiles of the body-side holding section and the contact elements can have a tongue-and-groove geometry and / or form an undercut. For example, the holding section can have a shape that tapers towards the center of the tool holder, while the associated contact element comprises a correspondingly shaped groove (or vice versa).

[0020] Another possible embodiment provides for the base body to be located on the soil tillage implement during the application and removal of material. This allows for quick and easy repairs to be carried out directly on-site.

[0021] In a further possible embodiment, the tool holder comprises two opposing body-side holding sections that form the inner sides of the tool holder. The cutting tool has two complementarily shaped, opposing outer sides of the tool holder, which form positive connections with the body-side holding sections transverse to the insertion direction (this refers in particular to a direction perpendicular to the insertion direction and perpendicular to a connecting line between the opposing body-side holding sections).

[0022] The profiles of the tool-side and body-side holding sections can have a tongue-and-groove geometry and / or form an undercut. For example, one of the holding sections can have a shape that tapers towards the other holding section, while the other holding section comprises a correspondingly designed groove. Such a tongue-and-groove connection forms a positive connection transversely to the insertion direction of the cutting tool, but still allows relative movement of the cutting tool along the insertion direction. To block the latter, a locking element can be provided, for example in the form of a locking pin that can be inserted through corresponding recesses. In a further possible embodiment, the tool holder forms a substantially U-shaped recess, the lateral webs of which each have body-side holding sections.The body-side holding section can extend along the entire inside of the U-shaped recess. Alternatively, other recess shapes are conceivable, for example, a V-shape or a rectangular shape.

[0023] In a further possible embodiment, the cutting tool arrangement comprises a locking pin, which, for locking the cutting tool in the tool holder of the base body, is inserted through corresponding recesses formed in both the cutting tool and the base body and overlapping when the cutting tool is fully inserted. The locking pin, in particular, blocks movement of the cutting tool relative to the base body along the insertion direction.

[0024] In another possible embodiment, the recess in the base body intended for the locking pin is formed at least partially in a body-side holding section. In this case, the recess is thus located in particular in an area where material is applied and removed during the repair process.

[0025] In one possible embodiment, no material is applied and subsequently removed in an area of ​​the body-side holding section where the recess is located. The area of ​​the recess is thus deliberately excluded from material application and removal.

[0026] In an alternative possible embodiment, the area of ​​the recess is not removed, but rather material is also added and removed in the area of ​​the body-side holding section where the recess is located. The subsequent removal of material in the area of ​​the recess takes place in such a way that the recess subsequently has a defined width for accommodating the locking pin. This prevents the locking pin from subsequently no longer fitting into the recess of the base body due to the material addition and removal.

[0027] In another possible embodiment, the soil cultivation tool is a milling tool, in particular a milling wheel of a trench cutter. The repair, ie, the material removal and addition according to the invention, takes place in particular on-site at the milling wheel.

[0028] In another possible embodiment, the application and removal of material takes place while the cutting wheel is mounted on the trench cutter. Alternatively, the cutting wheel can be removed from the trench cutter and attached to an external holding device while the repair process takes place. The holding device can be, for example, a device according to DE 10 2020 126 976 A1.

[0029] Further features, details, and advantages of the invention will become apparent from the exemplary embodiment explained below with reference to the figures. They show:

[0030] Figure 1: the cutting tool arrangement according to the invention according to a preferred embodiment in a side view;

[0031] Figure 2: the main body of the cutting tool arrangement in a side view; and

[0032] Figure 3: the main body of the cutting tool arrangement in a top view.

[0033] Figure 1 shows a preferred embodiment of the cutting tool arrangement 10 in a side view. The cutting tool arrangement 10 comprises a base body 12, which is fastened, in particular welded, to a soil cultivation device (not shown here). The soil cultivation device can be a cutting wheel of a trench wall cutter. The base body 12 comprises a tool holder 14, which can be seen in Figures 2 and 3, which show the base body 12 alone in a side view (Figure 2) and in a plan view (Figure 3), as well as a cutting tool 20. In the view of Figure 1, the cutting tool 20 is inserted into the tool holder 14, which in the embodiment shown here is designed as a cutting tooth that projects above the base body 12 at the top (i.e. on the side facing away from the soil cultivation device) and is used to remove and crush soil material.In the embodiment shown here, the base body 12 has a flat shape (as does the cutting tool 20) and can also be referred to as a fin.

[0034] The cutting tool 20 is subject to high wear and is therefore replaceable. To do so, the cutting tool 20 can be removed from the tool holder 14 after a locking pin 24 locking the cutting tool 20 to the base body 12 has been removed. The base body 12, however, remains firmly connected to the soil tillage implement.

[0035] As can be seen in Figures 2 and 3, the tool holder 14 is designed as a substantially U-shaped recess, with the inner sides of the recess forming a continuous body-side holding section 16. In Figure 2, the dashed line 22 indicates the insertion direction of the cutting tool 20. The body-side holding section 16 has a convex profile tapering toward the center of the tool holder 14, transverse to the insertion direction.

[0036] The cutting tool 20 has, on its short outer sides, which border on the base body 12 in the inserted state (cf. Figure 1), a corresponding tool-side holding section which has a profile complementary to the body-side holding section 16 (i.e., in the exemplary embodiment shown here, an inwardly tapering, concave groove). In the inserted state, the tool-side and body-side holding sections form a positive-locking connection between the base body 12 and the cutting tool 20 that is transverse to the insertion direction 22 (in Figure 3 this is the top-bottom direction). In the exemplary embodiment shown here, the body-side holding section 16 runs along the entire U-shaped recess. Alternatively, only certain partial sections (e.g., only the lateral webs) could have a body-side holding section 16.

[0037] In Figure 2, a round notch 17 can be seen in the body-side holding section 16 of the right, longer web of the base body 12, which forms a recess 17 for the locking pin 24. The cutting tool 20 has a bore that overlaps with the recess 17 when fully inserted, so that the locking pin 24 can be inserted and the cutting tool 20 is locked to the base body 12.

[0038] Due to the very high force acting on the cutting tool 20, the base body 12 becomes severely deformed or worn over time. The areas most subject to stress include those regions of the body-side holding section 16 that are located in the "right" or long web (shown in Figure 2) above the recess 17 and in the "left" or short web opposite the recess 17. This deforms the base body 12 to such an extent that the cutting tool 20 has excessive play in the tool holder 14 and the forces occurring during operation affect the locking pin 24. This subjects the locking pin to high forces and can ultimately be destroyed. As a result, the cutting tool 20 is no longer locked in the base body 12 and can fall out.

[0039] In order to repair the base body 12 or restore it to its original condition without having to remove the base body 12 from the soil tillage implement or replace it entirely, according to the method according to the invention, material is applied in a targeted manner to the body-side holding section 16 (in particular over its entire length, whereby material could optionally be applied only in certain areas - e.g., in the aforementioned, most heavily stressed areas). This is done in particular by means of build-up welding of a material that is higher in strength than the original material of the base body 12. This reduces the width of the tool holder 14 so that it once again has sufficient oversize to be machined.

[0040] For this purpose, in a subsequent step, the previously applied material is partially removed again until the tool holder 14 has the intended width for secure and stable reception of the cutting tool 20. The width of the tool holder 14 can be measured using a special measuring device. A suitable and particularly simple measuring device can be designed in the form of a mobile caliper, the mutually displaceable contact elements of which preferably have a profile complementary to the body-side holding section 16.

[0041] If the base body 12 or its tool holder 14 has been brought back to the specified dimensions and tolerances by the method according to the invention, the cutting tool 20 (or a new cutting tool 20) can be reinserted into the tool holder 14, whereby the cutting tool 20 is now again seated in the tool holder 14 without play.

[0042] The method according to the invention can be carried out directly in the field, i.e. for example directly on the cutting wheel mounted on a trench wall cutter or on a holding device according to DE 10 2020 126 976 A1, which makes the repair process more efficient and cost-effective than previous repair methods.

[0043] List of reference symbols:

[0044] 10 Cutting tool arrangement

[0045] 12 basic bodies

[0046] 14 Tool holder

[0047] 16 body-side holding section

[0048] 17 Recess for locking pin

[0049] 20 cutting tools

[0050] 22 Insertion direction

[0051] 24 locking pin

Claims

Patent claims 1. A method for repairing a cutting tool assembly (10) comprising a base body (12) secured to a soil tillage implement with a tool holder (14) and a cutting tool (20) replaceably mountable in the tool holder (14), wherein the tool holder (14) comprises at least one body-side holding portion (16) which, in the connected state, forms a positive connection with a tool-side holding portion of the cutting tool (20) transversely to an insertion direction (22) of the cutting tool (20), the method comprising the steps of: - applying material to the at least one body-side holding section (16) so that the width of the tool holder (14) in the region of the at least one body-side holding section (16) is reduced transversely to the insertion direction (22), and - removing a part of the previously applied material in order to enlarge the tool holder (14) in the region of the at least one body-side holding section (16) to a defined width transversely to the insertion direction (22).

2. Method according to claim 1, wherein the application of material to the at least one body-side holding section (16) is carried out by build-up welding, wherein the material applied by build-up welding preferably has the same or higher strength than the material of the at least one body-side holding section (16).

3. Method according to claim 1 or 2, wherein the width of the tool holder (14) in the region of the at least one body-side holding section (16) is measured transversely to the insertion direction (22) by means of a measuring device in order to reduce the width to a defined value by the targeted removal of previously applied material.

4. Method according to the preceding claim, wherein the measuring device comprises a first contact element, a second contact element which is displaceable relative to the first contact element, in particular displaceable by hand, and a detection device for measuring a distance between the two contact elements, wherein the contact elements are designed to contact the at least one body-side holding section (16) and an opposite side section of the tool holder (14) from the inside.

5. Method according to one of the preceding claims, wherein the at least one body-side holding section (16) is formed integrally with the base body (12).

6. Method according to one of the preceding claims, wherein the at least one body-side holding section (16) has a profile transverse to the insertion direction (22) deviating from a flat shape, in particular a profile tapering towards the center of the tool holder.

7. Method according to one of the preceding claims, wherein the base body (12) is located on the soil cultivation device during the application and removal of material.

8. Method according to one of the preceding claims, wherein the tool holder (14) comprises two body-side holding sections (16) which are opposite one another and form inner sides of the tool holder, wherein the cutting tool (20) has two complementarily shaped tool-side holding sections which form opposite outer sides and which form positive connections with the body-side holding sections (16) transversely to the insertion direction (22).

9. Method according to the preceding claim, wherein the tool holder (14) forms a substantially U-shaped recess, the lateral webs of which have body-side holding sections (16).

10. Method according to one of the preceding claims, wherein the cutting tool arrangement (10) comprises a locking pin (24) which, for locking the cutting tool (20) in the tool holder (14) of the base body (12), is inserted through recesses formed in the cutting tool (20) and in the base body (12) and which overlap one another when the cutting tool (20) is fully inserted.

11. Method according to the preceding claim, wherein the recess (17) of the base body (12) provided for the locking pin (24) is formed at least partially in a body-side holding section (16).

12. The method according to claim 11, wherein no material is applied and subsequently removed in a region of the body-side holding section (16) in which the recess (17) is located.

13. The method according to claim 11, wherein material is also applied in a region of the body-side holding section (16) in which the recess (17) is located, and the subsequent removal of the material in the region of the recess (17) takes place in such a way that the recess (17) subsequently has a defined width for receiving the securing pin (24).

14. Method according to one of the preceding claims, wherein the soil working tool is a milling tool, in particular a milling wheel of a trench wall cutter.

15. A method according to the preceding claim, wherein the application and removal of material takes place while the cutting wheel is mounted on the trench wall cutter or after the cutting wheel has been removed from the trench wall cutter and attached to an external holding device.

Images