Cutting tools with radially adjustable tool holders

Abstract

A cutting tool (10) includes a tool body (12) and a tool holder (14) for cutting inserts (10), wherein the tool holder (14) is radially adjustable in an adjustment direction in a housing (20) of the tool body (12) by means of a positioning element (22), wherein the radial position of the tool holder (14) in the housing (20) is adjustable in a predetermined increment by means of the positioning element.

Description

Technical Field

[0001] The present invention relates to a cutting tool, such as a drill bit or a milling cutter, having a radially adjustable tool holder for the cutting insert. Background Technology

[0002] Cutting tools having a tool body and at least one tool holder attached to the tool body for cutting inserts are known. The advantage of such cutting tools is that, depending on the intended use, an appropriate tool holder can be selected and attached to the housing of the tool body.

[0003] The diameter of the cutting tool is defined by the radial width of the tool holder relative to the longitudinal axis of the cutting tool and the radial dimension of the holder relative to the longitudinal axis of the cutting tool.

[0004] Typically, tool holders are manufactured at their maximum width, which therefore determines the maximum diameter of the cutting tool. If the diameter of the cutting tool needs to be reduced, the tool holder must therefore be ground to the desired width. This process requires considerable effort and is irreversible. Summary of the Invention

[0005] The purpose of this invention is to provide a cutting tool whose diameter can be easily and precisely adjusted, specifically reversibly.

[0006] The object of the present invention is achieved by a cutting tool comprising a tool body and a tool holder for cutting inserts, wherein the tool holder is radially adjustable in a housing of the tool body by means of a positioning element, wherein the radial position of the tool holder in the housing can be adjusted in a predetermined increment along an adjustment direction by means of the positioning element.

[0007] The present invention is based on the fundamental idea of ​​providing an additional positioning element for connecting a tool holder to a tool body, wherein the positioning element allows the radial position of the tool holder to be adjusted in predetermined increments (i.e., at predetermined intervals). This eliminates the need to change the tool holder itself to alter the width of the cutting tool, thereby omitting the laborious grinding operation of removing material from the tool holder.

[0008] Furthermore, the radial position of the tool holder can be changed several times, and in this way, the same tool holder can be used to utilize cutting tools of various diameters. Therefore, for example, the diameter of the cutting tool can be flexibly adapted between two cutting operations.

[0009] The positioning element can be a screw comprising an axial portion having external threads, whereby the axial portion extends parallel to the adjustment direction. Utilizing the external threads, the positioning element can be reliably fixed relative to the tool holder, or the positioning element can be fixed relative to the housing of the tool body.

[0010] For example, the axial portion engages with a reverse thread in the tool holder or tool body to connect the positioning element to the tool holder or tool body, respectively. The reverse thread may be formed in the housing of the tool holder or tool body.

[0011] At the same time, the predetermined increment along the adjustment direction can be based on the pitch of the external thread. In other words, among other things, the predetermined increment can be determined by selecting the pitch of the external thread.

[0012] Furthermore, the positioning element may include a fixed section by means of which the positioning element is fixed to the tool body or tool holder in a manner that prevents rotation in a plane transverse to the adjustment direction, specifically in a plane perpendicular to the adjustment direction. By means of the fixed section, the secure holding of the positioning element is thus ensured during operation of the cutting tool, thereby ensuring that the diameter does not undesirably change during operation of the cutting tool, for example, due to radial forces acting on the positioning element and / or the tool holder.

[0013] The fixed section is specifically arranged on the external threaded end of the positioning element opposite to the axial section, such that the positioning element is connected to the tool holder at the first end via the axial section and to the tool body and the tool holder at the second end via the fixed section.

[0014] To prevent rotational fixing of the retaining section, it can be shape-locked to the tool body or tool holder. In this way, the positioning element is securely held, and the components of the cutting tool are particularly easy to assemble.

[0015] For example, the fixed portion has a polygonal outer contour in a plane transverse to the adjustment direction, specifically in a plane perpendicular to the adjustment direction. In this way, the predetermined increment can be based on the number of outer surfaces of the fixed segment predetermined by the polygonal outer contour.

[0016] Specifically, the predetermined increment is based on a combination of the pitch of the external thread in the axial portion and the number of outer surfaces of the fixed section defined by the polygonal outer contour.

[0017] Generally speaking, there are no further restrictions on the type of polygonal outline, as long as it is reliably fixed.

[0018] For example, the outer contour of a polygon is a triangle, square, pentagon, or hexagon.

[0019] To facilitate easier mounting of the fixed section in the tool holder or housing, the polygonal outer contour may include at least one rounded corner. Additionally, using rounded corners on the outer contour of the fixed section reduces wear on components involved in the connection between the tool holder and the tool body.

[0020] All corners of the outer contour of a polygon can also be rounded.

[0021] The polygonal outer contour can be point-symmetric, specifically point-symmetric about a central longitudinal axis that extends through the positioning element and is parallel to the adjustment direction of the tool holder.

[0022] In one variation, the fixed section is specifically inserted into a recess in the tool body or tool holder in a shape-locking manner. This results in a particularly simple assembly of the tool holder onto the tool body.

[0023] Additionally, the retaining section can be non-destructively and releasably inserted into the recess, allowing the tool holders to be interchangeably inserted into the receptacle. This allows the same tool holders to be removed and reinstalled in different radial positions.

[0024] Alternatively or additionally, the fasteners of the tool body or tool holder may engage the fixing portion. In other words, the fixing section may have a recess into which the fastener engages.

[0025] The configuration previously explained for the polygonal outer contour of the fixed section is similarly applicable to the fastening elements and recesses of the fixed section.

[0026] The fixed section can be the head of the positioning element, specifically having a larger diameter than the axial portion with external threads.

[0027] The recess can have multiple circumferential abutment surfaces, each of which contacts a side surface of the fixing segment. The interaction between the abutment surfaces of the recess and the side surfaces of the fixing segment ensures that the fixing segment is secured in a particularly simple way to prevent rotation, specifically by means of shape-fit locking.

[0028] Provided there is sufficient circumferential contact surface to securely hold the stationary section and prevent rotation, the recess can also have fewer circumferential contact surfaces than the stationary section has side surfaces. In other words, the recess can be an opening on at least one side. This configuration further simplifies the insertion of the stationary section into the tool body or tool holder.

[0029] Alternatively, the recess may surround the fixing section on all sides in a plane transverse to the adjustment direction, specifically in a plane perpendicular to the adjustment direction. In this way, the fixing section can be fixed particularly well against radial forces during the operation of the cutting tool.

[0030] The adjustment direction is specifically perpendicular to the longitudinal axis of the tool body. In this way, a change in the radial position of the tool holder immediately translates into a change in the diameter of the cutting tool.

[0031] The type of cutting tool is not further restricted. Particularly advantageous is the possibility of adjusting the diameter of the cutting tool by changing the radial position of the tool holder in a rotating cutting tool. Examples of cutting tools include drills or end mills.

[0032] In addition to the positioning element, the tool holder can be attached to the tool body via one or more other components. In this way, the requirement for connection via the positioning element can be reduced.

[0033] For example, the blade holder can be additionally secured in the housing by means of a fastening screw, wherein the fastening screw extends laterally to the adjustment direction, specifically perpendicular to the adjustment direction.

[0034] Therefore, the adjustment direction can be transverse to the longitudinal axis of the cutting tool, or specifically perpendicular to the longitudinal axis of the cutting tool. Attached Figure Description

[0035] Other features and characteristics of the invention will become apparent from the following description of exemplary embodiments and the accompanying drawings, which should not be construed as limiting. The drawings show:

[0036] - Figure 1 This is a side view of the cutting tool according to the present invention.

[0037] - Figure 2 yes Figure 1 A partially transparent illustration of a selected component of the cutting tool.

[0038] - Figure 3 yes Figure 1 A perspective view of the tool body of a cutting tool.

[0039] - Figure 4 yes Figure 1 A perspective view of the tool holder for cutting tools.

[0040] - Figure 5 yes Figure 1 A perspective view of the mounting position of the positioning element for the cutting tool.

[0041] - Figure 6 yes Figure 1 A partially transparent illustration of the selected component of a variant of the cutting tool.

[0042] - Figure 7 yes Figure 6 A perspective view of the tool body of the cutting tool, and

[0043] - Figure 8 yes Figure 6 A perspective view of the tool holder for a cutting tool.

[0044] Figure 1 A cutting tool 10 according to the invention is shown, which has a tool body 12, two tool holders 14 inserted into the tool body, and a plurality of cutting inserts 16 respectively mounted in the tool holders.

[0045] It goes without saying that there can also be only one knife clip 14 or more. Figure 1 The two tool holders 14 shown are also illustrated. Similarly, each tool holder 14 may contain fewer or more cutting blades 16 than in the illustrated embodiment.

[0046] The cutting tool 10 also includes a centering pin 18, which is centered along the longitudinal axis L of the tool body 12, which is the axial direction of the tool body 12.

[0047] The cutting tool 10 is a rotary cutting tool configured to rotate about a longitudinal axis L during operation to perform a cutting operation on a workpiece (not shown).

[0048] In the illustrated embodiment, the cutting tool 10 is a spiral drill bit. However, the cutting tool can also be another type of cutting tool, such as other types of drill bits or milling cutters.

[0049] Each of the tool holders 14 is mounted in its associated housing 20 of the tool body 12.

[0050] The width of the tool holders 14 is such that they protrude from or are flush with the housing 20 in the radial direction perpendicular to the longitudinal direction L. Therefore, the diameter of the cutting tool 10 is defined not only in the width of the tool body 12, but also in the radial position of the tool holders 14.

[0051] The radial position of each tool holder 14 can be adjusted along the adjustment direction V via a positioning element 22 associated with the corresponding tool holder 14. Figure 2 It can be seen in the partially transparent illustration.

[0052] The positioning element 22 is a screw that includes an axial portion 24 with external threads and a retaining section 26, which in the illustrated embodiment is configured as the head of the screw and has a larger diameter than the axial portion 24.

[0053] The axial portion 24 extends parallel to the adjustment direction V and is arranged at the first axial end of the positioning element 22.

[0054] The axial portion 24 engages with the housing 28 of the tool holder 14, which has a reverse thread corresponding to the external thread of the axial portion 24, so that the positioning element 22 can be screwed into or out of the tool holder 14.

[0055] The fixed section 26 is located at the second axial end of the positioning element 22 opposite to the first axial end, and is inserted into the recess 30 of the tool body 12.

[0056] Figure 3 A perspective view of the cutter body 12 is shown, in which the recess 30 is more easily identifiable.

[0057] The recess 30 has a substantially square inner contour and has a plurality of circumferential abutment surfaces 32 connected together by rounded corners.

[0058] As in Figure 4 As can be seen in the perspective view, the fixed section 26 has a shape corresponding to the recess 30. Therefore, the fixed section 26 has a square outer contour with rounded corners in the plane transverse to the adjustment direction V, that is, in the plane perpendicular to the adjustment direction V.

[0059] Therefore, the fixed section 26 has four sides 34 that contact the circumferential abutment surface 32 of the recess 30 in the mounting positions of the tool holder 14 and the positioning element 22, as in Figure 5 As can be seen particularly clearly in the detailed images.

[0060] Due to the interaction between the fixed section 26 and the recess 30, the positioning element 22 is fixed to the tool body 12 in a manner that prevents rotation in a plane transverse to the adjustment direction V. In other words, as long as the fixed section 26 is inserted into the recess 30, it is impossible to rotate along... Figure 5 The arrow P shown rotates.

[0061] Thus, the radial position of the tool holder 14 is defined by the position of the fixing section 26 in the recess 30 and the screw depth of the axial portion 24 in the tool holder 14.

[0062] The resulting shape-fit locking between the fixed section 26 and the recess 30 prevents the radial position of the tool holder 14 from changing undesirably during the operation of the cutting tool 10.

[0063] If the radial position of the tool holder 14 is to be changed and thus the final diameter of the cutting tool 10 is to be changed, the tool holder 14 can be removed from the recess 30 together with the positioning element 22, the screw depth of the positioning element 22 can be changed by rotating the positioning element 22 (e.g. by rotating the fixing section 26), and then the fixing section 26 can be reinserted into the recess.

[0064] According to the present invention, it is assumed that the radial position of the blade holder 14 in the housing 20 can be adjusted in a predetermined increment, that is, adjusted only by a predetermined multiple of a predetermined interval.

[0065] In the illustrated embodiment, the predetermined increment is based on the interaction between the pitch of the external thread of the axial portion 24 and the outer contour of the fixed section 26.

[0066] like Figure 5 As shown, the fixed section 26 can only be inserted into the recess 30 of the tool body 12 when the side surface 34 defined by the outer contour of the fixed section 26 and the abutting surface 32 of the recess 30 are aligned and complementary.

[0067] In the illustrated embodiment where the fixed section 26 has a substantially square outer contour, this means that the fixed section 26 must be twisted 90° before it can be inserted into the recess 30 before it can be re-aligned.

[0068] In other words, for each full circle of the fixed section 26 having a substantially square outer contour, there are four possible orientations for the fixed section 26 to be inserted into the recess 30.

[0069] The interaction between the 90° rotation and the pitch of the external thread of the axial section 24 causes the screw depth of the positioning element 22 into the tool holder 14 to change between two possible insertion positions of the positioning element 22, which corresponds to a predetermined increment (i.e., one-quarter of the gear height of the thread in this example), meaning that the radial position of the tool holder 14 in the housing 20 can be adjusted by an increment.

[0070] It goes without saying that the predetermined increment can be changed by the configuration of the external thread and the fixed section 26.

[0071] Specifically, the fixed section 26 may also have a different outer contour than the embodiment shown in the figure. The only decisive factor is that the fixed section is fixed to the tool body 12 in a way that prevents rotation.

[0072] Therefore, the fixed section 26 can have any polygonal outer contour in a plane transverse to the adjustment direction V, as long as the recess 30 can maintain the obtained fixed section 26 in a way that prevents rotation, for example by having an inner contour that is complementary to the polygonal outer contour of the fixed section 26.

[0073] The polygonal outline specifically corresponds to a regular polygon. For example, instead of a square outline, fixed segment 26 can have a triangular, pentagonal, or hexagonal outline.

[0074] Figure 6 A variation of the cutting tool 10 is illustrated, which essentially corresponds to the cutting tool previously described; therefore, only the differences will be discussed below. The same reference numerals indicate the same or functionally identical components, and refer to the preceding text.

[0075] In a variation of the cutting tool 10, the recess 30 is not located in the tool body 12, but in the tool holder 14. Similarly, the receiving seat 28 is not located in the tool holder 14, but in the tool body 12.

[0076] Therefore, the axial portion 24 engages with the tool body 12, and the fixed section 26 is fixed in the tool holder 14 in a manner to prevent rotation.

[0077] Figure 7 It shows something similar to Figure 3A perspective view of the tool body 12, where the positioning element 22 has been screwed into the tool body 12.

[0078] Figure 8 A perspective view of a tool holder 14, based on a variant of the cutting tool 10, is shown.

[0079] As in Figure 8 As can be seen, in the variant, the recess 30 has fewer circumferential abutment surfaces 32 than the side surfaces 34 of the fixing section 26. Therefore, the recess 30 is open, and the fixing section 26 is not surrounded by the recess 30 on all sides. However, the presence of the abutment surfaces 32 further ensures that the fixing section 26 can only be received and fixed in the recess 30 with a predetermined alignment, allowing the radial position of the tool holder 14 to be changed in predetermined increments.

[0080] In general, the cutting tool according to the invention is characterized in that the position of the tool holder 14 and thus the diameter of the cutting tool 10 can be adjusted precisely and in a few simple steps.

Claims

1. A cutting tool (10) comprising a tool body (12) and a tool holder (14) for cutting inserts (16), wherein the tool holder (14) is radially adjustable in an adjustment direction in a housing (20) of the tool body (12) by means of a positioning element (22), wherein the radial position of the tool holder (14) in the housing (20) is adjustable in a predetermined increment by means of the positioning element.

2. The cutting tool (10) according to claim 1, wherein the positioning element (22) is a screw, the screw including an axial portion (24) having external threads, and wherein the axial portion (24) extends parallel to the adjustment direction.

3. The cutting tool (10) according to claim 1 or 2, wherein the positioning element (22) includes a fixing section (26) by means of which the positioning element (22) is fixed to the tool body (12) or the tool holder (14) in a manner to prevent rotation in a plane transverse to the adjustment direction.

4. The cutting tool (10) according to claim 3, wherein the fixing section (26) is shaped-fitted to the tool body (12) or the tool holder (14).

5. The cutting tool (10) according to claim 3 or 4, wherein the fixed section (26) has a polygonal outer contour in the plane transverse to the adjustment direction.

6. The cutting tool (10) according to claim 5, wherein the polygonal outer contour is point-symmetric.

7. The cutting tool (10) according to any one of claims 3 to 6, wherein the fixing section (26) is inserted into the recess (30) of the tool body (12) or the tool holder (14).

8. The cutting tool (10) according to claim 7, wherein the recess (30) includes a plurality of circumferential abutment surfaces (32), and each of the circumferential abutment surfaces (32) contacts a side surface (34) of the fixed section (26).

9. The cutting tool (10) according to any one of the preceding claims, wherein the adjustment direction is perpendicular to the longitudinal axis of the tool body (12).

10. The cutting tool (10) according to any one of the preceding claims, wherein the cutting tool (10) is a drill bit or a milling cutter.

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