Tool blade, tool holder, system, and machine tool

Abstract

The invention relates to a tool blade (14) which has a structure (24), that comprises at least two elements (22), on at least one lateral surface (26) of the tool blade (14), wherein the structure (24), with its elements, is rotationally symmetrical about a central blade rotational axis (R) of the tool blade (14) for a rotational angle of less than 360°, in particular of at most 180°, but is not mirror-symmetrical with respect to any diameter of the tool blade (14) extending through the blade rotational axis (R). The invention also relates to a tool holder (12), a tool blade system (15), and a machine tool (10). Said tool allows for particularly safe operation.

Description

[0001] Tool blade, tool holder, system and machine tool

[0002] Description

[0003] The invention relates to a tool blade, for example a circular saw blade. Such tool blades can be used together with machine tools such as circular saws or angle grinders. Such tool blades often require correct mounting. Otherwise, saw teeth, for example, are incorrectly aligned, meaning that a saw blade does not cut at all or does not cut optimally. There is also a risk that the machine tool will jam in a machined workpiece, which could result in a sudden recoil or counter-torque. The machine tool could be ripped from the hand of a user. Accidents and injuries can result. The same applies if the machine tool is guided by a construction robot. This can also result in failures or even damage.

[0004] The object of the present invention is therefore to provide a tool blade and devices for using such a tool blade which enable particularly safe use thereof.

[0005] The object is achieved by a tool blade which has a structure comprising at least two elements on at least one side surface of the tool blade, wherein the structure with its elements is rotationally symmetrical about a central blade rotation axis of the tool blade to a rotation angle of less than 360°, in particular of at most 180°, but not mirror-symmetrical to any diameter of the tool blade passing through the blade rotation axis.

[0006] The tool blade therefore has an n-fold rotational symmetry, where n is greater than 1.

[0007] Rotational symmetry and mirror symmetry can be assessed in a vertical plan view of the side surface. This is based on the surprisingly simple yet surprisingly effective concept that such a combination of rotational symmetry in conjunction with a lack of mirror symmetry gives the tool blade an orientation, thus preventing confusion of the sides of the tool blade during assembly.

[0008] This ensures that the tool blade can only be mounted the correct way round. Reversed mounting is impossible. This ensures that the tool blade is used properly, and the risks described above can be minimized or even eliminated.

[0009] Furthermore, the rotational symmetry ensures that the tool blade remains balanced. Even at high rotation speeds, it can rotate with minimal vibration. This also allows the machine tool operator to guide the tool blade particularly safely by hand. Health damage caused by high vibration loads to the operator's hand can be avoided.

[0010] The tool blade can, for example, be a saw blade for a circular saw. It can also be a wood saw blade. It is also conceivable that the tool blade is designed as a blade for an angle grinder. In general, it can be a saw blade or a sanding blade, for example, for grinding stone, such as concrete, wood, or the like.

[0011] A special case of such n-fold rotational symmetry arises when the structure is point-symmetric to the blade rotation axis, i.e., with 2-fold rotational symmetry. For this purpose, two of the elements of the structure can be formed in pairs with point-symmetrical relationship to the blade rotation axis.

[0012] At least one of the elements can comprise a recess. The element can be or comprise a through-hole. Such recesses can be easily produced, for example by drilling or milling. Since the recesses do not protrude beyond the surface of the side face of the tool blade, the tool blade can also be used with conventional machine tools, for example conventional circular saws or angle grinders. In particular, the recesses do not hinder assembly on such conventional machine tools. However, it is also conceivable for at least one of the elements to comprise a projection that protrudes from the side face. At least two such projections can be provided to ensure the necessary rotational symmetry.

[0013] Because the protrusions protrude from the side surface, the user can immediately see during assembly whether the tool blade is mounted correctly. If the machine tool is configured to secure the tool blade to the protrusions on the machine tool, the tool blade cannot be mounted reversed at all and would immediately slip off the machine tool. This immediately prevents the user from operating the machine tool until the tool blade is mounted correctly.

[0014] At least two of the elements of the structure can be arranged at at least two different radii around the blade rotation axis. This makes it possible to influence the vibration behavior of the tool blade during rotation, enabling even lower vibration levels.

[0015] It is conceivable that the tool blade has a central through-opening, so that the tool blade can still be used for conventional machine tools, which usually require such a central through-opening.

[0016] It is also possible, however, for the tool blade to have no central through-hole. Instead, the tool blade can be and / or is directly secured to a suitably designed machine tool via its structural elements, particularly by means of its recesses and / or projections. By keeping a central area of ​​the tool blade filled with material, the stability of the tool blade can be improved.

[0017] A particularly simple, cost-effective structure, for example, may have only two elements. In this case, it is advantageous if the elements are not circular, in order to avoid mirror symmetry despite the small number of elements. To maintain rotational symmetry, the two elements should be opposite each other along a diameter through the blade rotation axis.

[0018] A particularly simple possibility for producing the structure also arises if at least one of the elements, in particular the at least two elements, comprises a non-circular shape, for example an elongated hole. Such a non-circular shape also makes it easier to stably fix the tool blade to the tool holder, at least partly with the aid of the elements. The edge, which is longer than a circular edge, results in an extended contact zone between the complementary elements of a tool holder engaging in the elements and the tool blade. This makes it possible to reduce compressive loads, and fraying of the elements can be reduced or avoided. This extends the service life of the tool blade.

[0019] The structure can also comprise at least two similar elements that differ in size. This creates design options that allow the vibration behavior during rotation of the tool blade to be further modified.

[0020] At least one of the elements may have a chamfer, allowing the tool blade to be mounted more easily in a machine tool's tool holder. The chamfer may also help reduce or eliminate sparks and noise from the tool blade during rotation.

[0021] The tool blade can have an electrical, magnetic, and / or electromagnetic function. In particular, the tool blade can have at least one electronic component. For example, the tool blade can be equipped with a sensor.

[0022] It is conceivable that at least one of the elements is electrically conductive. If the element has a recess or a through-opening, this can be understood to mean that a surface region of an edge of the recess or through-opening is formed from an electrically conductive material.

[0023] It is then further conceivable for the at least one element to be designed as an electrical contact. For example, if the tool holder of the machine tool has complementary mating contacts, electrical contact can be established between the machine tool and the electronics of the tool blade. The sensor can thus detect a property, such as a degree of wear, of the tool blade and transmit corresponding data to the machine tool via the elements. The tool blade can be driven, in particular by a machine tool, via at least one of the elements of the structure.

[0024] At least one of the elements of the structure can be located in an outer half, for example with a radius in the range of 55 to 100 percent, in particular within 65 to 85 percent, of the initial diameter of the tool blade. If the tool blade is driven by such an element located in the outer half, only small tangential forces acting on the tool blade are required to achieve a specific torque. The tool blade can be subjected to lower internal stresses during rotation. The service life of the tool blade can thus be increased. It is also conceivable to apply an increased torque to the tool blade due to the resulting improved durability.

[0025] For example, with cutting discs for angle grinders, it is advantageous if the element is not located too far out, for example in the area of ​​more than 85 percent of the initial diameter, as otherwise it could be affected by wear.

[0026] In addition to the technical effects mentioned, within the framework provided by the aforementioned measures to achieve the respective advantages, there are degrees of design freedom through fine positioning, size, color and shape of the elements, lettering and the like in order to give the tool blade a particularly appealing appearance.

[0027] The invention further includes a tool holder on which a tool blade of the type described above can be mounted. The tool holder has a complementary structure on at least one side surface of the tool holder, wherein the complementary structure comprises at least two complementary elements. The complementary structure with its complementary elements is rotationally symmetrical about a central axis of rotation of the tool holder to a rotation angle of less than 360°, in particular of at most 180°, but not mirror-symmetrical to any diameter of the tool holder passing through the axis of rotation.

[0028] Such a tool holder can serve as an adapter for conventional machine tools. A tool blade of the type described above can be mounted on it. The tool holder can have a mounting plate. The complementary structure can be formed on the mounting plate.

[0029] It is conceivable to mount the tool holder, in particular the mounting plate, on a conventional machine tool. Then the tool blade can also be used on a conventional machine tool converted in this way, with the advantages described above.

[0030] It's also conceivable to install such a tool holder directly on a machine tool. This eliminates the possibility of the tool blade being accidentally mounted upside down.

[0031] At least one of the complementary elements may have a chamfer to simplify the assembly of a tool blade.

[0032] The complementary structure can, in particular, be designed to complement the structure of the tool plate. For example, if the structure of the tool plate has recesses as elements, the complementary structure can have projections, for example in the form of pins, at the positions corresponding to the recesses as complementary elements.

[0033] The tool holder can be designed for tool-free assembly of the tool blade. In particular, if the tool blade as an element has at least one projection, for example an angled projection, the projection can be inserted into a recess in the tool holder. The tool blade can then be secured to the tool holder by means of a rear grip and / or a locking mechanism. This can take advantage of the fact that a laterally inverted assembly of the tool blade cannot occur. The locking mechanism and / or the rear grip can thus be designed such that they close automatically when the tool blade rotates or at least prevent the connection between the tool blade and the tool holder from automatically becoming loose.

[0034] At least one complementary element of the complementary structure can be electrically conductive. In the case of a recess or a through-opening, this can be understood to mean that a surface of an edge region of the complementary element is electrically conductive.

[0035] At least one of the complementary elements may have a chamfer so that when mounting the tool blade, it can be pushed more easily onto or into the complementary element.

[0036] Furthermore, a tool blade system falls within the scope of the invention, comprising a tool holder of the type described above and a tool blade of the type described above. In this system, the complementary structure of the tool holder is designed to complement the structure of the tool blade, so that the tool blade can be mounted on the tool holder without the possibility of reversed mounting.

[0037] Furthermore, the scope of the invention includes a machine tool configured to receive and rotate a tool blade, comprising a tool holder for receiving the tool blade, wherein the tool holder has a tool holder of the type described above. The machine tool can be, for example, a circular saw. It can also be an angle grinder. The machine tool can be a handheld power tool. It is also conceivable for the machine tool to be mounted on a construction robot, for example, for carrying out construction work in building construction, civil engineering, or industrial plant construction.

[0038] Especially in cases where the machine tool is designed and / or arranged on the end effector of a construction robot, additional sensors for checking whether a tool blade is mounted correctly on the machine tool can be dispensed with, or existing sensors can be simplified. For example, a sensor that simply checks for the presence of the tool blade in the tool holder may be sufficient. Especially with high levels of autonomy of the construction robot, the tool blade and, in particular, the tool blade system make it easier to meet relevant safety requirements.

[0039] Furthermore, weight can be saved, particularly on an end effector of the construction robot, thus improving its maneuverability.

[0040] In the case of hand-held power tools, the risks mentioned above for a user of the hand-held power tool can be reduced.

[0041] Further features and advantages of the invention will become apparent from the following detailed description of exemplary embodiments of the invention, based on the figures of the drawing, which illustrate details essential to the invention, and from the claims. The features shown therein are not necessarily to scale and are presented in such a way that the special features of the invention can be clearly seen. The various features can be implemented individually or in combinations in variants of the invention.

[0042] The schematic drawing shows embodiments of the invention and explains them in more detail in the following description.

[0043] They show:

[0044] Fig. 1 shows a section of a machine tool with a tool blade system,

[0045] Fig. 2 to

[0046] Fig. 10 several tool blades,

[0047] Fig. 11 a complementary element and

[0048] Fig. 12 a tool blade in a side view.

[0049] In the following description of the figures, the same reference numerals are used for identical or functionally corresponding elements to facilitate understanding of the invention.

[0050] Fig. 1 shows a side view of a section of a machine tool 10 with a tool holder 12 in which a tool blade 14 is mounted. The tool holder 12 and the tool blade 14 form a tool blade system 15.

[0051] The machine tool 10 is designed as an angle grinder.

[0052] The tool blade 14 is designed as a cutting disc, for example for cutting stone or metal.

[0053] The tool blade 14 has a central through-opening 16. With this through-opening, the tool blade 14 sits on a rotational axis 18 of the tool holder 12. The tool holder 12 further has a plurality of pin-shaped complementary elements 20 that engage with elements 22 of a structure 24. The elements 22 are designed as elongated holes and extend through the tool blade 14. They thus have a cross-section in the shape of a rounded rectangle. The complementary elements 20 are designed to be complementary to the elements 22. Therefore, in the illustrated embodiment, they also have a cross-section in the shape of a rounded rectangle.

[0054] Since the elements 22 protrude through the tool blade 14, the tool blade 14 has the structure 24 not only on its side surface 26 visible in Fig. 1, but also on the opposite side surface not visible in Fig. 1.

[0055] The elements 22 and thus also the complementary elements 20 run obliquely to their respective radius lines as well as obliquely to their respective tangents.

[0056] As a result, the structure 24, in particular its elements 22, exhibits a threefold rotational symmetry. At the same time, however, the structure 24 does not exhibit mirror symmetry to any diameter through the central through-opening 16, which forms a blade rotation axis of the tool blade 14.

[0057] The complementary elements 20 form a complementary structure 28. The complementary structure 28 is thus complementary to the structure 24. It thus has the same threefold rotational symmetry while simultaneously lacking mirror symmetry to any diameter through the rotation axis 18.

[0058] Fig. 2 shows a tool blade 14 designed as a circular saw blade, for example, for machining wood materials. In particular, in this embodiment, the tool blade 14 has a plurality of saw teeth 30 as a circular saw blade, of which only one saw tooth 30 is provided with a reference numeral to simplify the illustration in Fig. 2. Furthermore, the center point of the tool blade 14 and thus a blade rotation axis R of the tool blade 14 is marked.

[0059] The tool blade 14, in turn, has a structure 24 formed from elements 22. The elements 22 are designed as circular through-openings. A total of four elements 22 are provided, each formed on two different radii r1, r2 and arranged opposite one another in pairs. The structure 24 is thus point-symmetric, i.e., it has twofold rotational symmetry.

[0060] In pairs, elements 22 are offset from their neighboring elements 22 by a central angle alpha. The central angle alpha is less than 90° and greater than 0°, for example, in the range of 10° to 40°.

[0061] Thus, the structure 24 again has no mirror symmetry to any diameter through the central through-opening 26 or to the blade rotation axis R of the tool blade 14.

[0062] Fig. 3 to Fig. 10 show various embodiments of tool blades 14 in schematic representations. In particular, different structures 24 can be seen.

[0063] Fig. 3, 5, 7, 9 show embodiments with structures 24 which have a threefold rotational symmetry.

[0064] Fig. 4, 6, 8, 10 show embodiments with structures 24 which have a twofold rotational symmetry, i.e. a point symmetry.

[0065] Fig. 3 to 6 have elements 22 which are designed as elongated holes.

[0066] Fig. 7 to 10 have elements 22 which are circular in shape.

[0067] Fig. 3 and 5 show embodiments with a total of three elements 22.

[0068] Fig. 4 and 6 show embodiments with a total of two elements 22.

[0069] Fig. 7 and 9 show embodiments with a total of six elements 22.

[0070] Fig. 8 and 10 show embodiments with a total of four elements 22.

[0071] As can be seen from Figs. 7 and 8, rotational symmetry in the absence of mirror symmetry can also be achieved by arranging elements 22 on the same radius but differing in their shape, for example in their size.

[0072] The different structures 24 according to Figs. 3 to 10 also involve different bending stiffnesses and / or different vibration behaviors. Fig. 11 shows a complementary element 20. The complementary element 20 has a chamfer 32. In particular, the chamfer 32 is chamfered with a bevel angle beta in the range of 10° to 85°, in particular between 10° and 40°, for example 30°.

[0073] In the illustrated embodiment, the chamfer 32 is formed symmetrically to the longitudinal axis of the complementary element 20. In alternative embodiments, it is conceivable that the chamfer 32 is formed asymmetrically. An asymmetric chamfer 32 can facilitate the assembly of the tool blade 14.

[0074] Fig. 12 shows another tool blade 14 in a schematic side view. It has a total of four elements 22, of which only three elements 22 are visible due to the side view shown in Fig. 12. Another element 22 is concealed by another element 22.

[0075] In this embodiment, the elements 22 are designed as projections. Such a tool blade 14 can be mounted on a tool holder 12 (see Fig. 1), in which the complementary elements 20 are designed, for example, as blind holes. Then, during assembly, the elements 22 can be pushed into the blind holes or the complementary elements 20. The tool blade 14 can thus also be attached to the tool holder 12 by means of its elements 22.

[0076] List of reference symbols

[0077] 10 Machine tool

[0078] 12 tool holder

[0079] 14 Tool sheet

[0080] 15 Systems

[0081] 16 passage opening

[0082] 18 Rotation axis

[0083] 20 Complementary element

[0084] 22 elements

[0085] 24 Structure

[0086] 26 side surface

[0087] 28 Complementary structure

[0088] 30 sawtooth

[0089] R Blade rotation axis alpha Central angle r1 Radius r2 Radius

Claims

Patent claims 1 . Tool blade (14), in particular a circular saw blade, which has a structure (24) comprising at least two elements (22) on at least one side surface (26) of the tool blade (14), wherein the structure (24) with its elements is rotationally symmetrical about a central blade rotation axis (R) of the tool blade (14) to a rotation angle of less than 360°, in particular of at most 180°, but is not mirror-symmetrical to any diameter of the tool blade (14) passing through the blade rotation axis (R).

2. Tool blade (14) according to the preceding claim, characterized in that the structure (24) is point-symmetrical to the blade rotation axis (R).

3. Tool blade (14) according to one of the preceding claims, characterized in that at least one of the elements (22) comprises a recess, in particular a through opening (16) through the tool blade (14).

4. Tool blade (14) according to one of the preceding claims, characterized in that at least one of the elements (22) comprises a projection which projects from the side surface (26).

5. Tool blade (14) according to one of the preceding claims, characterized in that at least two of the elements (22) of the structure (24) are arranged on at least two different radii (r1, r2) around the blade rotation axis (R).

6. Tool blade (14) according to one of the preceding claims, characterized in that the tool blade (14) has a central through-opening (16).

7. Tool blade (14) according to one of the preceding claims, characterized in that at least one of the elements (22) comprises a non-circular shape, for example an elongated hole.

8. Tool blade (14) according to one of the preceding claims, characterized in that the structure (24) has at least two similar elements (22) which differ in their size.

9. Tool blade (14) according to one of the preceding claims, characterized in that at least one of the elements (22) has a chamfer.

10. Tool blade (14) according to one of the preceding claims, characterized in that at least one of the elements (22) is electrically conductive.

11. Tool holder (12) on which a tool blade (14) according to one of the preceding claims can be mounted, characterized in that the tool holder (12) has a complementary structure (28) on at least one side surface (26) of the tool holder (12), wherein the complementary structure (28) comprises at least two complementary elements (20), wherein the complementary structure (28) with its complementary elements is rotationally symmetrical about a central axis of rotation (18) of the tool holder (12) to a rotation angle of less than 360°, in particular of at most 180°, but not mirror-symmetrical to any diameter of the tool holder (12) running through the axis of rotation (18).

12. Tool blade system (15) comprising a tool holder (12) according to the preceding claim and a tool blade (14) according to one of claims 1 to 10, characterized in that the complementary structure (28) of the tool holder (12) is designed to be complementary to the structure (24) of the tool blade (14).

13. A machine tool (10) configured to receive and rotate a tool blade (14), for example a circular saw or an angle grinder, comprising a tool holder (12) for receiving the tool blade (14), wherein the tool holder (12) has a tool holder (12) according to claim 11.

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