Tool blades, tool mounting parts, systems, and power tools

Abstract

The present invention relates to a tool blade (14) having a structure (24) comprising at least two elements (22) on at least one side (26) of the tool blade (14), wherein the structure (24), together with its elements, is rotationally symmetric with respect to a rotation angle of less than 360°, particularly 180° at most, about the central blade rotation axis (R) of the tool blade (14), but is not mirror-symmetric with respect to any diameter of the tool blade (14) extending through the blade rotation axis (R). The present invention also relates to a tool mounting section (12), a tool blade system (15), and a power tool (10). The tool enables particularly safe operation.

Description

Technical Field

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[0001] The present invention relates to a tool blade, such as a circular saw blade.

Background Art

[0002] This type of tool blade can be used with power tools such as circular saws or angle grinders. This type of tool blade often needs to be correctly installed. Otherwise, the saw teeth are not correctly aligned, for example, as a result, the saw blade does not cut in an optimal way or does not cut at all. Furthermore, there is a risk that the power tool jams within the workpiece during machining and in some cases leads to a sudden reaction or reverse torque. The power tool can be torn out of the user's hand. As a result, accidents and injuries can occur. The same description applies when the power tool is guided by a construction robot. Here too, as a result, malfunctions or even damage can occur.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Therefore, an object of the present invention is to provide a tool blade that can be used particularly safely and an apparatus for using such a tool blade.

Means for Solving the Problems

[0004] This object is achieved by a tool blade having a structure with at least two elements on at least one of its sides, where, around the central blade rotation axis of the tool blade, the structure with the elements is rotationally symmetric with respect to a rotation angle of less than 360°, particularly at most 180°, but is not mirror-symmetric with respect to any diameter of the tool blade passing through the blade rotation axis.

[0005] Therefore, the tool blade has an n-fold rotational symmetry, where n is greater than 1.

[0006] The rotational symmetry and mirror symmetry can be evaluated in a plan view perpendicular to the side surface.

[0007] This is based on the idea that, despite its surprisingly simple design, it is unexpectedly effective: this combination of rotational symmetry and lack of mirror symmetry gives the tool blades a orientation that eliminates confusion between the sides of the tool blades while they are being mounted.

[0008] As a result, the tool blades are always mounted correctly. Mounting them incorrectly is eliminated. Therefore, the tool blades are used correctly, minimizing or even eliminating the risks initially described.

[0009] Furthermore, rotational symmetry ensures that the tool blade remains balanced. This allows the tool blade to rotate with virtually no vibration, even at high speeds. This also allows power tool users to guide the tool blade by hand, particularly safely, avoiding health damage caused by high vibration loads on the user's hands.

[0010] A tool blade could be, for example, a saw blade for a circular saw. It could also be a saw blade for woodworking. It is also conceivable to design a tool blade as a blade for an angle grinder. In general, it could be a saw blade, or an abrasive disc for grinding materials such as stone, concrete, or wood.

[0011] Such a special case of n-rotational symmetry can be obtained when the structure is point-symmetric with respect to the blade rotation axis, i.e., when it is two-fold rotational symmetry. For this purpose, in particular, each pair of elements of the structure can be formed point-symmetric with respect to each other with respect to the blade rotation axis.

[0012] At least one of the elements may include an aperture. The element may be or may include a through-opening. This type of aperture can be easily fabricated, for example, by drilling or milling. Therefore, since the aperture does not protrude beyond the side surface of the tool blade, the tool blade can also be used with conventional power tools, such as conventional circular saws or angle grinders. In particular, the aperture does not prevent attachment to this type of conventional power tool.

[0013] However, it is also possible that at least one of the elements includes a projection extending from the side. To ensure the required rotational symmetry, at least two such projections may be provided.

[0014] The fact that the protrusions extend from the sides allows the user to immediately verify whether the tool blade is properly installed, even during installation. If the power tool is configured to secure the tool blade to the tool with the protrusions, it is completely impossible to install the tool blade in reverse, as the tool blade will immediately slide off the power tool. Therefore, the user is directly prevented from operating the power tool until the tool blade is properly installed.

[0015] At least two of the structural elements can be positioned on 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, and thus enable operation with even less vibration.

[0016] The tool blade may have a central through-hole, which would allow it to continue to be used with conventional power tools that generally require such a central through-hole.

[0017] However, it is also possible for the tool blade to not have a central through-opening. Conversely, the tool blade may and may be directly fixed to a well-designed power tool through its structural elements, particularly by its aperture and / or projections. The stability of the tool blade can be improved by the fact that the central area of ​​the tool blade also remains occupied by the material.

[0018] A particularly simple structure that can be manufactured at low cost may have, for example, only two elements. In this case, it is advantageous if the elements are not circular in design in order to avoid mirror symmetry despite the small number of elements. To obtain rotational symmetry, the two elements must be positioned opposite each other along the diameter passing through the blade rotation axis.

[0019] A particularly simple possibility for manufacturing this structure is also obtained when at least one, and especially at least two, of the elements have a non-circular shape, such as an elongated hole. This type of non-circular shape, at least as a contributing factor, further facilitates the stable fixing of the tool blade to the tool mount by the element. The edge extending relative to the circular edge provides an extended contact area between the complementary element of the tool mount that engages with the element and the tool blade. Thus, it is possible to reduce the pressure load and reduce or avoid wear on the element. Thus, the life of the tool blade can be extended.

[0020] The structure can also have at least two elements of the same type but different sizes. This provides the possibility of design configurations that allow for additional modification of the vibrational behavior of the tool blade during rotation.

[0021] At least one of the elements may have a chamfered portion, thus allowing the tool blade to be easily attached to the tool mounting portion of the power tool. The chamfered portion may also contribute to reducing or avoiding the scattering of sparks and the generation of noise from the rotating tool blade.

[0022] The tool blade can have an electrical function, a magnetic function, and / or an electromagnetic function. In particular, the tool blade can have at least one electronic system. For example, a sensor can be attached to the tool blade.

[0023] It is conceivable that at least one of the elements is conductive. If the element has an aperture or through-opening, it can be understood that this means that the surface area of the edge of the aperture or through-opening is formed of a conductive material.

[0024] It is further conceivable that at least one element is designed as an electrical contact. Thus, for example, if the tool mounting part of a power tool has mating contacts of complementary design, an electrical contact can be established between the power tool and the electronics of the tool blade. Thus, for example, a sensor can detect the characteristics of the tool blade, such as the degree of wear, and transmit corresponding data to the power tool via the element.

[0025] Via at least one of the elements of the structure, the tool blade can be driven, in particular by a power tool.

[0026] At least one of the elements of the structure can be located in the outer half, for example, in the range from 55 to 100 percent, particularly in the range from 65 to 85 percent, of the initial diameter of the tool blade, in terms of radius. When the tool blade is driven via such an element located in the outer half, only a small tangential force acting on the tool blade is required to achieve a specific torque. The tool blade may be subject to minor internal stresses during rotation. Thus, it is possible to extend the life of the tool blade. Also, it is conceivable to apply an increased torque to the tool blade for the improvement in durability that can thereby be achieved.

[0027] However, in the case of a cutting disk for an angle grinder, for example, it is advantageous if the element is not located too far outwards, for example, not in a region exceeding 85 percent of the initial diameter. This is because otherwise it may be prone to wear.

[0028] Furthermore, in addition to the above-described technical effects, within the scope of the above countermeasures for achieving each advantage, by means of fine positioning, due to the size, color, and shape of the elements, and also by means of lettering, etc., the degree of freedom in design can be achieved, and it is possible to give a particularly attractive appearance to the tool blade.

[0029] The scope of the present invention further includes a tool mounting portion to which a tool blade of the above type can be attached. The tool mounting portion has a complementary structure on at least one side surface of the tool mounting portion, the complementary structure includes at least two complementary elements, and here, with respect to the central rotation axis of the tool mounting portion, the complementary structure having the complementary elements is rotationally symmetric with respect to a rotation angle of less than 360°, particularly at most 180°, but is not mirror symmetric with respect to any diameter of the tool mounting portion passing through the blade rotation axis.

[0030] This type of tool mounting portion can function as an adapter for a conventional power tool. A tool blade of the above type can be attached thereto.

[0031] The tool mounting portion can have a mounting plate. The complementary structure can be formed on the mounting plate.

[0032] It is conceivable to arrange the tool mounting portion, particularly the mounting plate, on a conventional power tool. Then, the tool blade can also be used with the thus-converted conventional power tool having the above-described advantages.

[0033] It is also conceivable to directly provide this type of tool mounting portion on a power tool. Therefore, in the case of such a power tool, the possibility that the tool blade is accidentally attached reversely is eliminated.

[0034] At least one of the complementary elements can have a chamfer, thus simplifying the attachment of the tool blade.

[0035] In particular, complementary structures can be designed to be complementary to the structure of the tool plate. For example, if the structure of the tool plate has an aperture as an element, the complementary structure may have a projection, for example in the form of a pin, as a complementary element at a position corresponding to the aperture.

[0036] The tool mounting section may be designed to mount the tool blade without the need for tools. In particular, if the tool blade has at least one projection as an element, for example, an angled projection, the projection can be inserted into the aperture of the tool mounting section. The tool blade can then be secured to the tool mounting section by a rear engaging means and / or a latch mechanism. In this regard, the fact that reverse mounting of the tool blade is impossible can be taken advantage of. Therefore, the latch mechanism and / or rear engaging means can be designed to automatically lock when the tool blade rotates, or at least to eliminate automatic disengagement of the connection between the tool blade and the tool mounting section.

[0037] At least one complementary element of a complementary structure may be conductive. In the case of an aperture or through-opening, this can be understood as meaning that the surface of the end region of the complementary element is conductive.

[0038] At least one of the complementary elements may have a chamfered portion, which allows for easier pressing of the tool blade onto or within the complementary element during installation.

[0039] The scope of the present invention further includes a tool blade system having the above-described type of tool mounting portion and the above-described type of tool blade. In this system, the complementary structure of the tool mounting portion is designed to be complementary to the structure of the tool blade, and thus it becomes possible to mount the tool blade to the tool mounting portion in a manner that eliminates the possibility of reverse mounting.

[0040] The scope of the present invention further encompasses power tools having a tool mounting section configured to receive and rotate a tool blade, wherein the tool mounting section is of the type described above. The power tool may be, for example, a circular saw. It may also be an angle grinder. The power tool may be a handheld power tool. It is also conceivable that the power tool be mounted on a construction robot to perform construction work, for example, in a building, civil engineering site, or industrial plant.

[0041] More precisely, when power tools are formed and / or positioned on the end effector of a construction robot, it is possible to omit additional sensors to verify whether the tool blade is properly mounted on the power tool, or to simplify the sensors that exist in principle. For example, a sensor system that simply verifies the presence of the tool blade within the tool mounting section may suffice. More precisely, when the autonomy of the construction robot is high, the tool blade, and especially the tool blade system, can more easily meet the associated safety requirements.

[0042] Furthermore, it is possible to reduce the weight on the end effector of construction robots in particular, and therefore improve their maneuverability.

[0043] In the case of handheld power tools, the risks mentioned earlier for the user of handheld power tools can be reduced.

[0044] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention and the claims, with reference to the drawings illustrating essential details of the invention. Features shown therein should not necessarily be considered to scale, but rather are shown in a manner that clearly illustrates the specific features of the present invention. Various features can be implemented individually or collectively in any combination in modifications of the present invention.

[0045] Exemplary embodiments of the present invention are shown in the schematic diagrams and described in detail below. [Brief explanation of the drawing]

[0046] [Figure 1] Details of power tools with a tool blade system are shown. [Figure 2] This shows the tool blade. [Figure 3] This shows the tool blade. [Figure 4] This shows the tool blade. [Figure 5] This shows the tool blade. [Figure 6] This shows the tool blade. [Figure 7] This shows the tool blade. [Figure 8] This shows the tool blade. [Figure 9] This shows the tool blade. [Figure 10] This shows the tool blade. [Figure 11] Showing complementary elements [Figure 12] The tool blade is shown in a side view. [Modes for carrying out the invention]

[0047] In the subsequent diagrams, the use of the same reference numerals for identical or functionally corresponding elements in each case will facilitate understanding of the present invention.

[0048] Figure 1 is a side view detailing a power tool 10 having a tool mounting section 12 to which a tool blade 14 is attached. The tool mounting section 12 and the tool blade 14 form a tool blade system 15.

[0049] Power tool 10 is designed as an angle grinder.

[0050] The tool blade 14 is designed, for example, as a cutting disc for cutting masonry or metal.

[0051] The tool blade 14 has a central through-opening 16. This opening allows the tool blade 14 to seat on the rotation axis 18 of the tool mounting portion 12.

[0052] The tool mounting section 12 further has a plurality of pin-shaped complementary elements 20 that engage with the elements 22 of the structure 24. The elements 22 are designed as elongated holes through which the tool blades 14 pass. Therefore, they have a rounded rectangular cross-section. The complementary elements 20 are designed to be complementary to the elements 22. Therefore, in the illustrated embodiment, they also have a rounded rectangular cross-section.

[0053] Since element 22 protrudes through the tool blade 14, the tool blade 14 has a structure 24 not only on the side 26 visible in Figure 1, but also on the opposite side not visible in Figure 1.

[0054] Element 22, and therefore complementary element 20, also extend diagonally with respect to their respective radius lines and diagonally with respect to their respective tangent lines.

[0055] As a result, the structure 24, and in particular its element 22, has triple rotational symmetry. However, at the same time, the structure 24 does not have mirror symmetry with respect to any diameter passing through the central through-opening 16 that forms the rotation axis of the tool blade 14.

[0056] The complementary element 20 forms a complementary structure 28. Thus, the complementary structure 28 is designed to be complementary to structure 24. Therefore, it has the same triple rotational symmetry while simultaneously lacking mirror symmetry with respect to any diameter passing through the axis of rotation 18.

[0057] Figure 2 shows a tool blade 14 designed as a circular saw blade for machining, for example, woody materials. In particular, the tool blade 14 as a circular saw blade in this embodiment has multiple saw teeth 30, and for the sake of simplicity in the illustration, only one of the saw teeth 30 is given a reference numeral in Figure 2. The center point of the tool blade 14, and therefore the blade rotation axis R of the tool blade 14, is also shown.

[0058] The tool blade 14 further has a structure 24 formed from elements 22. Element 22 is designed as a circular through-opening. In this case, a total of four elements 22 are provided, each formed on two different radii r1, r2, and each positioned opposite each other in pairs. Thus, the structure 24 is point-symmetric, i.e., has twofold rotational symmetry.

[0059] Each element 22 is offset in pairs from its adjacent 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°.

[0060] Therefore, the structure 24 again does not have mirror symmetry with respect to any diameter passing through the central through-opening 26, or with respect to the blade rotation axis R of the tool blade 14.

[0061] Figures 3 to 10 schematically show various embodiments of the tool blade 14. In particular, different structures 24 can be seen.

[0062] Figures 3, 5, 7, and 9 show embodiments having a structure 24 with three-fold rotational symmetry.

[0063] Figures 4, 6, 8, and 10 show embodiments of a structure 24 having two-fold rotational symmetry, i.e., point symmetry.

[0064] Figures 3 to 6 show an element 22 designed as an elongated hole.

[0065] Figures 7 to 10 show elements 22 of a circular design.

[0066] Figures 3 and 5 show an embodiment having a total of three elements 22.

[0067] Figures 4 and 6 show an embodiment having a total of two elements 22.

[0068] Figures 7 and 9 show an embodiment having a total of six elements 22.

[0069] Figures 8 and 10 show an embodiment having a total of four elements 22.

[0070] As can be seen from Figures 7 and 8, rotational symmetry without mirror symmetry can be achieved even when the elements 22 are arranged on the same radius but have different shapes, such as different sizes.

[0071] The different structures 24 in Figures 3 to 10 are also associated with different bending stiffnesses and / or different vibration behaviors.

[0072] Figure 11 shows a complementary element 20. The complementary element 20 has a chamfered portion 32. In particular, the chamfered portion 32 is chamfered with a chamfer angle beta in the range of 10° to 85°, especially between 10° and 40°, for example, 30°.

[0073] In the illustrated exemplary embodiment, the chamfered portion 32 is formed symmetrically with respect to the longitudinal axis of the complementary element 20. In an alternative embodiment, the chamfered portion 32 may be formed asymmetrically. An asymmetrical chamfered portion 32 can make it easier to mount the tool blade 14.

[0074] Figure 12 shows a schematic side view of another tool blade 14. It has a total of four elements 22, of which only three are visible in the side view shown in Figure 12. The remaining elements 22 are hidden by other elements 22.

[0075] In this exemplary embodiment, element 22 is designed as a projection. This type of tool blade 14 can be mounted on a tool mounting section 12 (see Figure 1), where, for example, a complementary element 20 is designed as a blind hole. During the mounting process, element 22 can be pushed into the blind hole or the complementary element 20. Thus, the tool blade 14 can also be fixed to the tool mounting section 12 by its element 22. [Explanation of symbols]

[0076] 10 Power tools 12 Tool mounting section 14 Tool blade 15 Systems 16 Through-opening 18 rotation axes 20 Complementary elements 22 elements 24 Structure 26 Side view 28 Complementary Structures 30 serrated teeth R blade rotation axis Alpha center angle r1 radius r2 radius

Claims

1. A tool blade (14) having a structure (24) comprising at least two elements (22) on at least one side (26) of the tool blade (14), in particular a circular saw blade, wherein the structure (24) comprising the elements is rotationally symmetric with respect to a rotation angle of less than 360°, in particular 180° at most, but is not mirror-symmetric with respect to any diameter of the tool blade (14) passing through the blade rotation axis (R).

2. The tool blade (14) according to claim 1, characterized in that the structure (24) is point-symmetric with respect to the blade rotation axis (R).

3. The tool blade (14) according to claim 1 or 2, characterized in that at least one of the elements (22) has an aperture, in particular a through opening (16) through which the tool blade (14) passes.

4. The tool blade (14) according to claim 1 or 2, characterized in that at least one of the elements (22) has a projection protruding from the side surface (26).

5. The tool blade (14) according to claim 1 or 2, 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. The tool blade (14) according to claim 1 or 2, characterized in that the tool blade (14) has a central through-opening (16).

7. The tool blade (14) according to claim 1 or 2, characterized in that at least one of the elements (22) has a non-circular shape, for example, an elongated hole.

8. The tool blade (14) according to claim 1 or 2, characterized in that the structure (24) has at least two elements (22) of the same type but different in size.

9. The tool blade (14) according to claim 1 or 2, characterized in that at least one of the elements (22) has a chamfered portion.

10. The tool blade (14) according to claim 1 or 2, characterized in that at least one of the elements (22) is conductive.

11. A tool mounting portion (12) to which a tool blade (14) according to claim 1 or 2 can be attached, wherein the tool mounting portion (12) has a complementary structure (28) on at least one side surface (26) of the tool mounting portion (12), the complementary structure (28) comprises at least two complementary elements (20), and the complementary structure (28) comprising the complementary elements is rotationally symmetric with respect to a rotation angle of less than 360°, particularly up to 180°, about a central rotation axis (18) of the tool mounting portion (12), but is not mirror-symmetric with respect to any diameter of the tool mounting portion (12) passing through the rotation axis (18).

12. A tool blade system (15) comprising a tool mounting portion (12) according to claim 11 and a tool blade (14) according to claim 1 or 2, characterized in that the complementary structure (28) of the tool mounting portion (12) is designed to be complementary to the structure (24) of the tool blade (14).

13. An electric power tool (10), such as a circular saw or an angle grinder, configured to receive a tool blade (14) and rotate it, wherein the electric power tool (10) comprises a tool mounting portion (12) for receiving the tool blade (14), and the tool mounting portion (12) comprises the tool mounting portion (12) described in claim 11.

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