Handheld power tools, as well as axial support devices and working elements for such power tools.

Abstract

The present invention relates to a handheld power tool (10) comprising a tool housing (12), a motor (24), a tool shaft (36) having a rotating shaft (40) and driven by the motor (24), and further comprising a working element (38) that can be detachably attached in the axial direction to the tool shaft (36) from the outside of the tool housing (12), and which, after being attached to the tool shaft (36), is held against the tool shaft (36) by an axial holding device (80). The axial retaining device (80) comprises a first element (36;38) composed of one of a working element (38) and a tool shaft (36), a second element (38;36) composed of the other of the working element (38) and the tool shaft (36), at least two locking elements (70) assigned to the first element (36;38) so as to be radially movable between a retracted position and a locked position, and at least one recess (66) assigned to the second element (38;36) to accommodate the locking elements (70) when they are in the locked position. The locking elements (70), or the second element (38;36) in and / or around the at least one radial recess (66), include a magnetic material, and at least the other of the locking elements (70) and the second element (38;36) in and / or around the at least one radial recess (66) includes a magnetic material or a ferromagnetic material. After the working element (38) is attached to the tool shaft (36), the locking element (70) is automatically moved and held in place by magnetic force in its locked position and within at least one radial recess (66).

Description

Technical Field

[0001] The present invention relates to a hand-held power tool comprising a tool housing, a motor disposed therein, and a tool shaft having a rotational axis, the tool shaft being driven by the motor during operation to perform a rotational movement about its rotational axis, and a distal end of the tool shaft being accessible from outside the tool housing. The power tool is removably attachable axially from outside the tool housing to the distal end of the tool shaft parallel to the rotational axis of the tool shaft, and further comprises a working element which is axially held against the tool shaft by an axial holding device after being attached to the tool shaft.

[0002] Furthermore, the present invention relates to an axial holding device for holding the working element of the hand-held power tool axially against the tool shaft of the power tool in an axial direction extending parallel to the rotational axis of the tool shaft after the working element has been axially attached from outside the tool housing to the distal end of the tool shaft. Finally, the present invention also relates to a working element of a hand-held power tool which is configured to be removably attached axially to the tool shaft of the power tool in an axial direction extending parallel to the rotational axis of the tool shaft, and which is further configured to be axially held by an axial holding device after the working element has been attached to the tool shaft.

Background Art

[0003] The above-described type of handheld power tool, taking the form of an electric power tool for angle sanding or polishing, is known, for example, from U.S. Patent Application Publication No. 2011 / 036604 (Chervon Corporation). The power tool comprises a tool housing and an electric motor located therein. The tool shaft of the power tool rotates about its axis of rotation by the electric motor. The distal end of the tool shaft is accessible from outside the tool housing. The power tool further comprises a working element that can be detachably attached from outside the tool housing to the distal end of the tool shaft, axially extending parallel to the axis of rotation of the tool shaft. After the working element is attached to the tool shaft, the working element is held axially relative to the tool shaft by an axial retaining device.

[0004] The first type of working element comprises an eccentric element and a backing pad. The backing pad is mounted on the eccentric element so as to be freely rotatable about a second axis of rotation of the backing pad that extends parallel to and at a distance from the axis of rotation of the tool shaft. The eccentric element is detachably mounted axially to the tool shaft and is held against the tool shaft by an axial retaining device. The second type of working element comprises only a backing pad that is detachably mounted axially to the tool shaft and is held against the tool shaft by an axial retaining device.

[0005] The distal end of the tool shaft is provided with an axial bore configured to accommodate a cylindrical pin, which is assigned to the eccentric element of a first type of working element, or alternatively, to the backing pad of a second type of working element. The proximal end of the cylindrical pin has an annular recess extending on the outer surface of the pin. A hollow cylindrical jacket radially defining the axial bore of the tool shaft has two opposing locking elements, each radially movable between a retracted position and a locked position. In the retracted position, the locking elements do not engage with the annular recess on the proximal end of the cylindrical pin, leaving an axial passage along the axial bore free, allowing the working element to be attached to the tool shaft and / or axially removed from the tool shaft. In the locked position, the locking elements engage with the annular recess, thereby axially holding the working element relative to the tool shaft.

[0006] Each locking element is designed as a lever element capable of pivoting tangentially to the axis of rotation of the tool shaft, around a pivot axis extending within the hollow cylindrical jacket of the tool shaft. The locking elements are held in the locked position by a spring element. The locking elements can be moved to their retracted position against the force of the spring element by a manually operated drive mechanism in the form of a push button. Each lever element has a front end on the first side of the pivot axis that engages with an annular recess assigned to the working element when the lever element is in its locked position, and a rear end on the second side opposite the pivot axis, which is configured to be actuated by the drive mechanism and the spring element.

[0007] Known drawbacks of power tools include the large number of moving parts, the fairly complex and intricate design, and the fact that operating the axial retaining mechanism by the power tool user is quite complicated, especially if the user is wearing work gloves. [Overview of the project] [Problems that the invention aims to solve]

[0008] Therefore, an object of the present invention is to simplify the design and operation of the axial holding device for a handheld power tool, and in particular to enable the operation of the axial holding device and the installation / detachment / removal / replacement of work elements by the user, even when wearing work gloves. [Means for solving the problem]

[0009] To solve the object of the present invention, a handheld power tool having the features of claim 1 is proposed. In particular, starting from the above-described type of power tool, the axial holding device is A first element composed of one of the following elements, namely a working element and a tool shaft, and a second element composed of the other of the same element, namely the working element and the tool shaft, At least one locking element is assigned to the first element so as to be radially movable between a retracted position in which at least one locking element is retracted into the first element and a locking position in which at least one locking element radially protrudes from the first element toward the second element, At least one recess assigned to a second element and having a radial extension, configured to accommodate a portion of at least one locking element when at least one locking element is in the locked position after the working element has been attached to the tool shaft, and Equipped with, The following elements, namely at least one of the locking element (70) and the second elements (38;36) in and / or around the at least one radial recess (66), include a magnetic material, and the other of the elements, namely at least one locking element (70) and the second elements (38;36) in and / or around the at least one radial recess (66), include a magnetic material or a ferromagnetic material, and as a result, after the working element is attached to the tool shaft, the at least one locking element automatically moves and is held in its locked position and within the at least one radial recess by magnetic force, thereby engaging with the at least one radial recess and holding the working element axially relative to the tool shaft. It is proposed that this be done.

[0010] Where multiple locking elements are referred to below, it always refers to at least one locking element. The advantage of the present invention is that once the working element is mounted axially on the tool shaft, the locking elements automatically engage with at least one radial recess. This automatic engagement is achieved by a substantially radially acting magnetic force between the locking element and each of the at least one radial recesses. In other words, once the working element is mounted axially on the tool shaft, the locking elements are forced to engage with each of the at least one radial recesses by magnetic forces acting between the locking element and at least one recess of a second element surrounding the radial recess and / or the material, respectively.

[0011] The engagement between the locking element and at least one radial recess is preferably a mechanical engagement. The locking element, held in the first element, mechanically engages with at least one radial recess of the second element, preventing relative axial movement between the first and second elements. For this purpose, a portion of the locking element remains in the first element, while another portion of the locking element enters at least one radial recess.

[0012] The present invention has the further advantage of not requiring a separate spring element to bias the locking element to its locked position. Similarly, no manually operated drive mechanism is required to move the locking element to the retracted position. When the working element is mounted on the tool shaft in a first axial direction, the locking element automatically moves to the locked position due to the magnetic force acting between the locking element itself and / or between the locking element and at least one radially extending recess. To remove the working element from the tool shaft, the user simply grasps the working element with one hand and pulls it in a second axial direction opposite to the first axial direction. This causes the locking element to automatically move to its retracted position against the magnetic force, making it possible to remove the working element axially from the tool shaft.

[0013] For this purpose, it is proposed that at least one locking element or a second element within at least a region of at least one radial recess includes a magnetic material. The other of the two elements, i.e., the second element within at least a region of at least one radial recess or at least one locking element, includes a magnetic or ferromagnetic material to realize a magnetic attraction, and therefore a magnetic force, between the locking element and the at least one radial recess after the working element has been mounted on the tool shaft, and to hold the locking element within the at least one radial recess by magnetic force.

[0014] In other words, according to the present invention, -One or more locking elements include or are made of a magnetic material, and a second element within the region of one or more radial recesses includes or is made of a ferromagnetic material, such as iron or steel. -One or more locking elements include or are made of a magnetic material, and a second element within the region of one or more radial recesses includes or is made of a magnetic material having the opposite polarity to the magnetic material of one or more locking elements. -One or more locking elements include or are made of a ferromagnetic material, such as iron or steel, and one or more second elements within the region of radial recesses include or are made of a magnetic material. Such embodiments can be realized.

[0015] The present invention should be emphasized that it functions perfectly well even if the first element comprises only a single locking element. Due to the magnetic force between the locking element and the material of the second element surrounding each recess and / or radial recess, once the working element is axially removable, the locking element automatically moves to its locking position and engages with the respective recess.

[0016] If the locking element assigned to the first element is made of a permanent magnet material, the locking elements are magnetically attracted to each other, even if the working element is not attached to the tool shaft, and as a result move radially inward and are held in the locked position. If the working element is axially mounted on the tool shaft, the magnetic interaction between the locking elements causes the locking elements to automatically enter into at least one recess assigned to the second element. This works perfectly well even if the tool shaft does not contain magnetic or ferromagnetic material in and / or around at least one radial recess. For this purpose, the tool shaft can be made of a completely non-magnetic and non-ferromagnetic material, such as plastic, or a non-magnetic and non-ferromagnetic material, such as aluminum. Naturally, if the tool shaft contains magnetic or ferromagnetic material in and / or around at least one radial recess, the radially acting magnetic force that holds the locking element in at least one radially extending recess after the working element is attached to the tool shaft will be stronger. For this purpose, the tool shaft can be made of a ferromagnetic material, such as steel.

[0017] The first element, which holds at least one locking element, is preferably made of a non-magnetizable material such as plastic or aluminum, if at least one locking element is made of a permanent magnetic material. This allows the locking element to move freely in the radial direction due to the magnetic force acting between the locking element itself and / or between the locking element and each of its at least one radial recess. The locking element is not held within the first element by the magnetic force acting between the locking element and the first element.

[0018] One or more locking elements may have a substantially spherical design. Alternatively, one or more locking elements may have a substantially rectangular parallelepiped shape. The opposing edges of the rectangular surface of the rectangular parallelepiped locking element facing the second element may be rounded or tapered. The locking element is oriented such that when the working element is axially mounted on the tool shaft, the surface having the rounded or tapered edge extends toward the second element into at least one recess. Preferably, the rounded or tapered edge of the locking element faces in opposite directions, i.e., upward and downward, along the axis of rotation of the tool shaft when the axis of rotation extends vertically.

[0019] The working element may have different forms. The first type of working element may comprise an eccentric element and a backing pad. The backing pad is mounted on the eccentric element so as to be freely rotatable about a second axis of rotation of the backing pad that extends parallel to and at a distance from the axis of rotation of the tool shaft. The eccentric element is axially removable from the tool shaft and is held axially relative to the tool shaft by an axial retaining device.

[0020] The backing pad may have a bottom surface configured to removably attach a sanding or polishing member thereto, for example, by a Velcro (registered trademark) attachment layer. The sanding member may include, for example, sanding paper or sanding fabric. The polishing member may include, for example, a pad containing a polishing material such as sponge or foamed material, wool, microfiber, etc. The backing pad may be made of metal and / or plastic material.

[0021] In the first type of working element, the eccentric element can be provided with a bearing in which a part of the backing pad is directly or indirectly held so as to be freely rotatable with respect to the eccentric element.

[0022] For this purpose, according to an embodiment of the present invention, the upper surface of the backing pad may include a cylindrical pin that is directly or indirectly held within the eccentric element so as to be freely rotatable about a second axis of rotation, particularly in a bearing attached or embedded in the bottom surface of the eccentric element. Further, the eccentric element may include a spindle held within a bearing so as to be freely rotatable about the second axis of rotation. The cylindrical pin of the backing pad may be attached to the distal end of the spindle or may form an integral part of the spindle. After attachment to the spindle, the backing pad is freely rotatable with respect to the eccentric element about the second axis of rotation together with the spindle.

[0023] Instead of the cylindrical pin, the backing pad can have a recess on its upper surface, and the recess is configured to axially accommodate the distal end of the spindle. To attach the backing pad to the distal end of the spindle, the distal end of the spindle is axially inserted into the recess.

[0024] In both embodiments (where the backing pad includes a cylindrical pin or a recess on its upper surface), after attaching the backing pad to the distal end of the spindle, the backing pad is axially retained relative to the spindle, for example, by screw connection, magnetic force, screws, etc. In the case of screws, the screw is passed through the central hole of the backing pad from below and screwed into the threaded axial bore at the distal end of the spindle on the upper surface of the backing pad, thereby fixing the backing pad between the screw head and the distal end of the spindle. It is also possible to realize the axial retention of the backing pad relative to the spindle by the axial retention device according to the present invention.

[0025] The eccentric element may include a further cylindrical pin on the side opposite to the backing pad. By using this further cylindrical pin, for example, by axially inserting the further cylindrical pin into the bore at the distal end of the tool shaft, the first type of working element can be axially attached to the tool shaft. The cylindrical pin may be attached to the eccentric element in a torque-proof manner or may form an integral part thereof. Alternatively, on the side opposite to the backing pad, the eccentric element may include a recess or a bore, whereby, for example, by accommodating the distal end of the tool shaft in the recess or bore of the eccentric element, the first type of working element can be axially attached to the tool shaft. The axial retention of the eccentric element relative to the tool shaft can be achieved by the axial retention device according to the present invention.

[0026] The attachment of the eccentric element to the tool shaft is preferably such that torque can be transmitted from the tool shaft to the eccentric element during the intended use of the power tool. When attached to the eccentric element of the first type of working element in the described manner, the backing pad performs a random orbital motion during the intended use of the power tool, that is, a superposition of forced rotation about the first axis of rotation and free rotation about the second axis of rotation.

[0027] If the free rotation of the backing pad relative to the tool housing is restricted or prevented, the backing pad will perform orbital or eccentric motion. The free rotation of the backing pad can be restricted or prevented, for example, by corresponding magnetically interacting magnetic elements (permanent magnets and / or ferromagnetic elements) assigned to the backing pad on the one hand and to the tool housing on the other, similar to those proposed in European Patent No. 3501732, which is incorporated herein by reference in whole. Alternatively, the free rotation of the backing pad can be restricted or prevented by elastic means interconnecting the upper surface of the backing pad to the tool housing, such as an elastic collar or a set of elastic elements.

[0028] A second type of work element may comprise only a backing pad that is axially and detachably attached to a tool shaft. The backing pad may comprise a bottom surface configured to detachably attach a sanding member or abrasive member, for example, by a Velcro® attachment layer, and a top surface configured to be attached to the distal end of the tool shaft so that torque can be transmitted from the tool shaft to the backing pad during the intended use of the power tool. Attachment may be made directly between the top surface of the backing pad and the tool shaft, or by an extension rod interposed between the top surface of the backing pad and the distal end of the tool shaft. Axial retention of the backing pad relative to the tool shaft can be achieved by an axial retaining device according to the present invention. When the second type of work element is attached to the backing pad in the manner described, the backing pad rotates around a first axis of rotation of the tool shaft during the intended use of the power tool. In this case, the first axis of rotation of the tool shaft and the second axis of rotation of the backing pad coincide.

[0029] In one embodiment, the upper surface of the working element facing the distal end of the tool shaft may have a cylindrical pin, and the distal end of the tool shaft is provided with an axial bore extending along the first axis of rotation of the tool shaft. To attach the working element to the tool shaft, the cylindrical pin of the working element can be inserted into the axial bore of the tool shaft.

[0030] In another embodiment, the upper surface of the working element facing the distal end of the tool shaft may have an axial bore, and the distal end of the tool shaft is provided with a cylindrical pin-shaped portion (hereinafter referred to as a cylindrical pin) extending along the first axis of rotation of the tool shaft. To attach the working element to the tool shaft, the cylindrical pin of the tool shaft can be inserted into the axial bore of the working element.

[0031] In a preferred embodiment of the present invention, it is proposed that the first element is a tool shaft and the second element is a working element. Thus, in this embodiment, the tool shaft holds the locking element so as to be radially movable, and the working element is provided with at least one radially extending recess. In particular, at least one radial recess may be provided on the circumferential surface of an element attached to or forming part of the working element. Such an element attached to or forming part of the working element may be, for example, a cylindrical pin or an axial bore. In the case of a cylindrical pin, at least one recess may be provided on the circumferential surface of the pin. In the case of an axial bore, at least one recess may be provided on the circumferential surface of the bore.

[0032] Depending on the design of the tool shaft and work element, the locking element moves radially outward or radially inward to reach its locked position. If the distal end of the tool shaft is provided with an axial bore for accommodating the cylindrical pin of the work element, the locking element moves radially inward to reach the locked position. If the distal end of the tool shaft is equipped with a cylindrical pin for insertion into the axial bore of the work element, the locking element moves radially outward to reach the locked position.

[0033] Similarly, depending on the design of the tool shaft and work element, at least one radial recess may be provided on the outer or inner surface of the work element. If the work element is provided with a cylindrical pin, at least one radial recess may be provided on the outer surface of the pin. Alternatively, if the work element is provided with an axial bore, at least one recess may be provided on the inner surface of the bore.

[0034] In another preferred embodiment of the present invention, it is proposed that the first element is a working element and the second element is a tool shaft. In this embodiment, the tool shaft is provided with at least one radially extending recess, and the working element holds the locking element so as to be radially movable. In particular, the circumferential surface of an element attached to or forming part of the tool shaft may be provided with at least one radial recess. Such an element attached to or forming part of the tool shaft may be, for example, a cylindrical pin or an axial bore at the distal end of the tool shaft. In the case of a cylindrical pin, at least one recess may be provided on the circumferential surface of the pin. In the case of an axial bore, at least one recess may be provided on the circumferential surface of the bore.

[0035] Depending on the design of the tool shaft and work element, the locking element moves radially outward or radially inward to reach its locked position. If the upper surface of the work element is provided with an axial bore for accommodating the cylindrical pin of the tool shaft, the locking element moves radially inward to reach its locked position. If the upper surface of the work element is provided with a cylindrical pin for insertion into the axial bore of the tool shaft, the locking element moves radially outward to reach its locked position.

[0036] Similarly, depending on the design of the tool shaft and work element, at least one radial recess may be provided on the outer or inner surface of the tool shaft. If the distal end of the tool shaft is provided with a cylindrical pin, at least one radial recess may be provided on the outer surface of the pin. Alternatively, if the distal end of the tool shaft is provided with an axial bore, at least one recess may be provided on the inner surface of the bore.

[0037] Preferably, the distal end of the cylindrical pin has a tapered or rounded surface to automatically pull away the locking element and push it radially outward into its retracted position when the cylindrical pin is inserted into the axial bore. Additionally or alternatively, the outer edge defining the inlet hole into the axial bore may have a tapered or rounded surface to facilitate the introduction of each cylindrical pin into the axial bore.

[0038] The axial bore and cylindrical pin are proposed to have axially extending portions having corresponding non-rotating cross-sections, which are configured to mechanically engage with each other after the cylindrical pin is inserted into the axial bore and the working element is mounted axially on the tool shaft. Preferably, once the cylindrical pin is inserted into each axial bore, the portions automatically engage with each other, thereby enabling the transmission of torque from the tool shaft to the working element during the intended use of the power tool. The non-rotating cross-section is preferably proposed to have the form of a polygon with equal side lengths, such as a triangle, square, pentagon, hexagon, or octagon.

[0039] In this embodiment, the locking element and at least one of its recesses are provided solely for axially holding the working element relative to the tool shaft. In particular, the axial holding device does not function to transmit torque from the tool shaft to the working element about the rotation axis of the tool shaft, and the same applies to the locking element and recesses. This significantly improves the durability and strength of the axial holding device, and therefore the entire power tool. When the working element is mounted axially to the tool shaft, the corresponding parts having non-rotating cross-sections automatically engage with each other, enabling torque transmission.

[0040] In another preferred embodiment, after the working element is mounted on the tool shaft, the surface of the radially movable locking element facing the second element and / or an inlet opening to at least one radially extending recess is defined, and after the working element is mounted on the tool shaft, the outer edge facing the first element is proposed to have a tapered or rounded surface to facilitate the automatic radial pushing of the locking element to its retracted position when the working element is removed from the tool shaft. The tapered or rounded surface serves to redirect the direction of the force acting on the locking element from axial (resulting in the axial removal of the working element from the tool shaft) to radial (to move the locking element to its retracted position).

[0041] Furthermore, it is proposed that the locking element and at least one radial recess have corresponding shapes in the portions that engage with each other (preferably mechanically) at least in the locked position of the locking element. This ensures a safe and secure locked position of the locking element within each of the at least one radial recess without mechanical play that could cause rattling noises during the operation of the power tool. In particular, it enables a play-free connection between the working element and the tool shaft.

[0042] According to a preferred embodiment of the present invention, after the working element is attached to the tool shaft, the locking elements are arranged equidistant from each other in the circumferential direction with respect to the rotation axis of the tool shaft or a second rotation axis of the working element. Preferably, the axial retaining device comprises at least two, preferably at least three, and particularly preferably at least four locking elements. Two locking elements are arranged facing each other at a circumferential distance of 180° relative to each other. Three locking elements are arranged at a circumferential distance of 120° relative to each other. Four locking elements are arranged at a circumferential distance of 90° relative to each other. For larger power tools, particularly those with larger dimensions of the tool shaft and working element, and heavier working elements, it may be recommended to provide more locking elements.

[0043] According to one embodiment of the present invention, the axial retaining device comprises one or more radial recesses, the same number as the number of locking elements provided in the axial retaining device. Alternatively, the axial retaining device comprises a single annular radial recess configured to accommodate at least a portion of all the locking elements present in the axial retaining device.

[0044] It should be emphasized that the axial holding device according to the present invention can be used in various types of power tools that require a rotating element to be mounted and held axially relative to the tool shaft. For example, the axial holding device can enable the axial holding of a working element, such as a backing pad with or without an eccentric element, relative to the tool shaft of a grinder or sanding machine. Furthermore, the axial holding device can also be used to axially hold the chuck of a drill, hammer drill, or cordless screwdriver relative to the tool shaft. In addition, the axial holding device can also be used to axially hold a grinding wheel relative to the tool shaft of a grinding machine.

[0045] Further features and advantages of the present invention will become apparent from the embodiments described below with reference to the accompanying drawings. It should be emphasized that each feature shown in the drawings and potentially described below with reference to a particular embodiment may be important to the present invention, either in itself or in the context of another embodiment, even if not explicitly shown in the drawings and / or not described below. In particular, one or more features shown in the drawings may be combined with any one or more other features in other drawings, even if they belong to a different embodiment. [Brief explanation of the drawing]

[0046] [Figure 1] This is a side view of a power tool according to the present invention in a preferred embodiment. [Figure 2] Figure 1 is a top view of the power tool. [Figure 3] This is a cross-sectional view along the vertical plane of the tool head of a power tool according to another preferred embodiment of the present invention. [Figure 4] This figure shows the locking element of the power tool of Figure 3 in a preferred embodiment in the first perspective view. [Figure 5] This is a second perspective view of the locking element in Figure 4. [Figure 6] This is a cross-sectional view along the vertical plane of the tool head of an electric tool according to another preferred embodiment of the present invention. [Figure 7] [Figure 8] [Modes for carrying out the invention]

[0047] Figures 1 and 2 show side and top views, respectively, of a handheld and / or manually guided power tool 10 embodied as a polishing machine or grinder. Alternatively, the power tool 10 according to the present invention can be embodied as a sander or grinder, or as a drill, cordless screwdriver, or mixer, to name a few examples.

[0048] The polisher 10 comprises a housing 12 consisting of substantially two main parts, namely a rear section 12a and a front section 12b. More specifically, the housing 12 comprises a rear section 12a, a distal end 12c, a front section 12b, and a front casing 12d. The rear section 12a is preferably made of a rigid plastic material. Naturally, the rear section 12a of the housing 12 can also be made of a different rigid material, such as metal or carbon fiber. Furthermore, the rear section 12a of the housing 12 may also include an area provided with a soft plastic material or an elastic material such as rubber to ensure a safe and comfortable grip, hold, and guide of the power tool 10 by the user. The rear section 12a of the housing 12 is preferably divided into two semi-shells by a substantially vertical plane, these semi-shells mounted to each other along a vertical plane and fastened together by screws 14.

[0049] The rear portion 12a of the housing 12 is preferably equipped with an operating lever 16 that is linked to a switch for turning the polisher 10 on and off, which is located inside the housing 12. The operating lever 16 may be equipped with a blocking mechanism 18 to prevent unintended operation of the tool 10. The operating lever 16 is rotatable about a pivot axis 20 that extends perpendicular to the longitudinal extension of the housing 12. In the embodiments shown in Figures 1 and 2, the operating lever 16 is located on the top surface of the housing 12. Of course, it is also possible to position the lever 16 on the bottom surface of the housing 12 (not shown). Alternatively, instead of the lever 16, one or more push buttons or rotary switches may be used to drive the power tool 10.

[0050] Furthermore, in the embodiments shown in Figures 1 and 2, the rear portion 12a of the housing 12 is provided with a rotating wheel 22 for adjusting the speed of the tool's motor 24. The rotating wheel 22 can preferably be coupled with a potentiometer located inside the housing 12. Of course, it is also conceivable to provide the speed adjustment function to the operating lever 16 or one or more push buttons or rotary switches. In that case, the rotating wheel 22 can be omitted.

[0051] The distal rear end 12c of the rear section 12a can be removed from the rest of the housing 12 to allow the battery 26 to be withdrawn from inside the rear section 12a of the housing 12. The battery 26 supplies the polisher 10 and its electronic components with the electrical energy required for their respective operation. Of course, the polisher 10 can also be operated with electrical energy from the commercial power supply. In that case, the battery 26 is not required, and the receptacle for the battery 26 in the housing 12 could also be used to house a transformer or other electrical circuit to convert the mains power supply voltage (e.g., 100V or 250V AC and 50Hz or 60Hz) to the operating voltage for the polisher 10's electronic components (e.g., DC 12V, 18V, or 24V) corresponding to the voltage supplied by the battery 26.

[0052] The distal end 12c of the housing 12 can be secured to the rear 12a by a snap-fit ​​connection with two opposing lateral snap-release knobs 28 for releasing the snap-fit ​​connection. To remove the distal rear end 12c from the rear 12a of the housing 12, the lateral snap-release knobs 28 are pressed to release the snap-fit ​​connection, allowing the distal rear end 12c of the housing 12 to be separated from the rear 12a, and the battery 26 to be pulled out of the housing 12. The distal end 12c of the housing 12 may be attached to the battery 26, or it may be in the form of a separate lid for independently closing the receptacle for the battery 26.

[0053] The rear portion 12a of the housing 12 can be provided with a plurality of cooling vents 30 having any desired shape and extensions, thereby allowing air to flow from the inside of the housing 12 to the environment during the operation of the power tool 10, and cooling the electronic components located inside the housing 12.

[0054] The front portion 12b of the housing 12 is substantially tubular and serves to house and guide the drive shaft 32 during rotation around the rotation axis 34, for example, by one or more bearings (e.g., bearing 86 in Figures 3 and 6). The drive shaft 32 is driven by the motor 24. For this purpose, the drive shaft 32 may form an integral part with the motor shaft or be attached to it. The tubular front portion 12b is preferably made of metal, such as aluminum, or a rigid plastic material. The front portion 12b can be removably attached to the rear portion 12a of the housing 12, for example, by screw connections or screws. Alternatively, the rear end of the front portion 12b may simply be sandwiched between the two semi-shells that make up the rear portion 12a of the housing 12. The front portion 12b can be held and fixed to the rear portion 12a of the housing 12 by fastening the two semi-shells together, for example, by screws 14. Alternatively, the front portion 12b forms an integral part with the rear portion 12a. In particular, the front portion 12b may also include two semishells, each of which may form an integral part with the respective semishell of the rear portion 12a of the housing 12.

[0055] An electric motor 24 is located inside the rear portion 12a of the housing 12, which is preferably embodied as a brushless (BL) motor, particularly a BL DC (BLDC) motor. Furthermore, a first gear mechanism (not shown) may be placed between the motor shaft and the drive shaft 32, which can set a specific transmission ratio between the rotational speed of the motor shaft and the rotational speed of the drive shaft 32. Depending on the design of the gear mechanism, the ratio can be 1, greater than 1, or less than 1. Typically, the ratio is greater than 1 because the motor shaft rotates faster than the drive shaft 32.

[0056] The power tool 10 may include a second gear mechanism 42 (see Figures 3 and 6) which may be provided to convert the rotational motion of the drive shaft 32 around the rotating shaft 34 into the rotational motion of the tool shaft 36 (see Figures 3 and 6) of the power tool 10 around a further rotating shaft 40. The two rotating shafts 34 and 40 intersect at a specific angle α between approximately 70° and 110°, particularly at approximately 90°. In the embodiments of Figures 1 and 2, the angle α of the two rotating shafts 34 and 40 is approximately 98°. The tool shaft 36 actsuates the working element 38 of the power tool 10.

[0057] The front end of the drive shaft 32, the second gear mechanism 42, and the tool shaft 36 are preferably located within a tool head 44 attached to the front end 12e of the front portion 12b of the tool housing 12. The tool head 44 preferably includes a tubular front casing 12d that serves to house and guide the tool shaft 36 during rotation around the rotation axis 40, for example, by one or more bearings (e.g., bearing 88 in Figures 3 and 6). The tool head 44 is preferably an integral part of the front portion 12b of the housing 12. It is preferably made of the same material as the tubular front portion 12b. A protective shroud 46 is removably attached to the lower end of the tubular front casing 12d surrounding at least a portion of the working element 38, for example, an eccentric element 54 (see Figures 3 and 6) or an extension rod (not shown), and interconnects the distal end of the tool shaft 36 with the backing pad 48 of the working element 38.

[0058] As can be seen from Figures 3 and 6, the second gear mechanism 42 may include a bevel gear set having two meshing bevel gears 50, 52. One bevel gear 50 may be mounted on the drive shaft 32 or may form an integral part with the drive shaft. The other bevel gear 52 may be mounted on the tool shaft 36 or may form an integral part with the tool shaft. The bevel gears 50, 52 may be made of plastic material or metal, such as brass. The bevel gear set 42 may include gear ratios greater than 1, less than 1, or equal to 1.

[0059] In contrast to the above, the first and second gear mechanisms can also be designed as a single gear mechanism located between the motor shaft and the tool shaft 36, preferably within the tool head 44. In this case, the single gear mechanism preferably has a gear ratio ≠ 1. Alternatively, the power tool 10 according to the present invention may not have any gear mechanism at all, in which case the tool shaft 36 rotates at the same speed around the same axis of rotation as the motor shaft and, if present, the drive shaft 32.

[0060] Furthermore, a printed circuit board (PCB) comprising electrical and electronic circuits and components that together form at least a portion of the control unit may be disposed within the housing 12. Preferably, the control unit comprises a microcontroller and / or microprocessor for processing a computer program programmed to perform a desired motor control function when processed on the microprocessor.

[0061] In contrast to the above, the power tool 10 may also be equipped with a pneumatic motor, particularly a pneumatic vane motor, instead of the electric motor 24. In that case, pressurized air may be supplied to the power tool 10 through an air inlet and sent to the pneumatic motor for its operation.

[0062] Generally speaking, according to the present invention, a first element is defined, which consists of a working element 38 or a tool shaft 36, and a second element is defined, which consists of the other of two elements, i.e., the tool shaft 36 or the working element 38. At least one locking element 70 is assigned to the first element 36;38. The locking element 70 is radially movable relative to the first element 36;38 between a retracted position in which at least one locking element 70 is retracted into the first element 36;38 and a locked position in which at least one locking element 70 radially protrudes from the first element 36;38 toward the second element 38;36. At least one recess 66 having a radial extension is assigned to the second element 38;36. At least one radial recess 66 is configured to accommodate a portion of at least one locking element 70 when the working element 38 is in the locked position after it has been attached to the tool shaft 36. At least one of the following elements, namely at least one locking element 70 and at least one second element 38;36 in and / or around the radial recess 66, is made of or from a magnetic material, and at least the other of the two elements, namely at least one second element 38;36 in and / or around the radial recess 66 and at least one locking element 70, is made of or from a magnetic or ferromagnetic material. At least one locking element 70 is automatically moved to and held in the locked position by magnetic force. After the working element 38 is axially mounted on the tool shaft 36, at least one locking element 70 is moved into at least one radial recess 66 and held therein by magnetic force. In other words, the working element 38 is held axially relative to the tool shaft 36 as a result of at least one locking element 70 engaging with at least one radial recess 66. The attachment of the working element 38 to the tool shaft 36 is preferably a torque-proof method that allows torque to be transmitted from the tool shaft 36 to the working element 38.

[0063] As can be seen from Figures 3 and 6, the first type of work element 38 may include an eccentric element 54 and a backing pad 48. The backing pad 48 has a bottom surface 56 configured to detachably attach a sanding member or abrasive member (not shown) to it, for example, by a Velcro® attachment. The sanding member may include paper, cloth, or plastic foil with abrasive particles embedded in its bottom surface, and a corresponding mounting layer on its upper surface for detachable attachment to the bottom surface 56 of the backing pad 48. The abrasive member may include a pad with a bottom surface containing sponge or foam material, wool, microfiber, etc., and a corresponding mounting layer on its upper surface for detachable attachment to the bottom surface 56 of the backing pad 48.

[0064] A cylindrical pin 58 may be provided on the upper surface of the backing pad 48, which is held within an eccentric element 54 and can rotate freely about a second axis of rotation 60 of the backing pad 48, which extends substantially parallel to and at a distance from the first axis of rotation 40 of the tool shaft 36. It is proposed that the cylindrical pin 58 is held directly or indirectly by a bearing 62 provided on the bottom surface of the eccentric element 54. In the embodiments of Figures 3 and 6, the spindle 90 is held within the bearing 62 so as to be able to rotate freely about the second axis of rotation 60, and the backing pad 48 is attached to the spindle 90, for example, by the cylindrical pin 58. As shown in Figures 3 and 6, the attachment of the cylindrical pin 58 to the spindle 90 can be achieved by a screw connection. Alternatively, attachment can also be achieved by a screw and / or by magnetic forces acting between the backing pad 48 or the cylindrical pin 58 and the eccentric element 54 or the spindle 90, respectively. It is also conceivable that the cylindrical pin 58 forms an integral part of the spindle 90. The backing pad 48 is preferably made of a hard plastic material, metal, or the like.

[0065] On the opposite side of the backing pad 48, the eccentric element 54 is provided with a further cylindrical pin 64 having at least one radial recess 66 on its outer circumferential surface. The further cylindrical pin 64 may be designed separately from the eccentric element 54 and may be attached to the eccentric element in a torque-proof manner, for example, by a screw connection. In the context of the present invention, "torque-proof" means that torque can be transmitted between two elements attached to each other, in this case from the further cylindrical pin 64 to the eccentric element 54 in at least one rotational direction. However, it is also conceivable that the further cylindrical pin 64 forms an integral part of the eccentric element 54. The further cylindrical pin 64 is preferably made of a ferromagnetic material, such as steel or any other suitable metal. The eccentric element 54 may also be made of a non-ferromagnetic metal or a hard plastic material.

[0066] The second type of work element shown in Figures 7 and 8 may comprise only a backing pad 48 having a bottom surface 56 configured to detachably mount a sanding member or abrasive member. The top surface of the backing pad 48 is provided with a cylindrical pin 58 (see Figure 8) which can be attached to an extension rod 92 or form an integral part of the extension rod. The cylindrical pin 58 or—if present—the extension rod 92 may have at least one radial recess 66 on its circumferential surface. The cylindrical pin 58 or the extension rod 92 is preferably made of a ferromagnetic material, such as steel or any other suitable metal.

[0067] In the embodiment shown in Figure 8, the extension rod 92 includes an axial bore 68 extending along the second rotation axis 60. At least one radial recess 66 is provided on the inner circumferential surface. In this case, the distal end of the tool shaft 36 includes a cylindrical pin-shaped portion (hereinafter referred to as cylindrical pin 64) that can be axially inserted into the bore 68.

[0068] In the embodiments shown in Figures 3 and 6, the tool shaft 36 has an axial bore 68 for accommodating a further cylindrical pin 64 of a first type of working element 38, or a cylindrical pin 58 or extension rod of a second type of working element 38. The bore 68 is preferably radially defined by a hollow cylindrical jacket 78 that forms an integral portion of the tool shaft 36.

[0069] Generally, the first element to which at least one locking element 70 is assigned, i.e., in the embodiments of Figures 3 and 4, the tool shaft 36 or its hollow cylindrical jacket 78, is preferably made of a non-magnetizable material such as plastic or aluminum, if at least one locking element 70 is made of a permanent magnetic material.

[0070] At least one locking element 70 is held radially movable within a hollow cylindrical jacket 78. Although only one locking element 70 on the right side of the rotation axis 40 is shown in Figures 3 and 6, another locking element on the left side opposite to the locking element 70 is omitted to allow for a more easily understood design and function of the axial retaining device 80 according to the present invention. In particular, on the left side of the rotation axis 40 where the other locking element 70 is located, the hollow cylindrical jacket 78 has a retaining receiver 72 for the other locking element 70. The retaining receiver 72 has a radial extension to allow for radial movement of the locking element 70. Furthermore, the retaining receiver 72 may be designed so that the locking element 70 does not fall out when the cylindrical pin 58 (or extension rod) or further cylindrical pin 64 of the working element 38 is removed from the bore 68. Naturally, a further locking element 70 may be provided at a given circumferential distance from the two locking elements 70, for example, at a distance of 90°.

[0071] As shown in Figure 7, the backing pad 48 of the second type of work element 38 may also be provided with an axial bore 68 configured to accommodate the pin-shaped distal end 64 of the tool shaft 36.

[0072] In an alternative embodiment, the locking element 70 is assigned to the working element 38, but at least one radially extending recess 66 is assigned to the tool shaft 36. If an axial bore 68 is provided on the extension rod 92 or a further cylindrical pin 64 of the working element 38, allowing the tool shaft 36 to be introduced axially, the retaining receiver 72 for the locking element 70 is preferably located within a hollow cylindrical jacket 78 that radially defines the axial bore 68 and forms an integral portion of the extension rod 92 or the further cylindrical pin 64. The locking element 70 is held within the retaining receiver 72 so as to project radially inward toward the axis of rotation 60 beyond the inner circumferential surface of the axial bore 68.

[0073] Generally speaking, the power tool 10 according to the present invention has an axial holding device 80 configured to hold the working element 38 relative to the tool shaft 36 in an axial direction parallel to the rotation axis 40 of the tool shaft 36 when the working element 38 is removably attached to the tool shaft 36 from the axial outside of the tool housing 12.

[0074] According to the present invention, the axial holding device 80 comprises a first element 36;38, which is composed of a tool shaft 36 or a working element 38, and a second element, which is composed of the other element, i.e., a working element 38 or a tool shaft 36. At least one locking element 70 is assigned to the first element 36;38, and at least one radial recess 66 is assigned to the second element 38;36. Thus, in the first embodiment (shown in Figures 3, 6 and 7), the first element may be composed of a tool shaft 36, and the second element may be composed of a working element 38 or a part thereof, i.e., a cylindrical pin 64 of the first type of working element 38, or an extension rod 92 of the second type of working element 38. In the second embodiment (shown in Figure 8), the first element may consist of a working element 38 or a part thereof, i.e., a cylindrical pin 64 of the first type of working element 38 or an extension rod 92 of the second type of working element 38, and the second element consists of a tool shaft 36.

[0075] The axial holding device 80 includes at least one locking element 70 that is held radially movable within the first element between a retracted position in which the at least one locking element 70 is retracted into the first element and a locked position in which the at least one locking element 70 radially protrudes from the first element toward the second element (see Figures 3, 6 to 8). As shown in Figures 3, 6 and 8, in the locked position, the locking element 70 protrudes radially inward. However, as shown in Figure 7, in another embodiment, the locking element 70 can protrude radially outward in the locked position.

[0076] Furthermore, the axial retaining device 80 includes at least one radial recess 66 provided on the second element, which is configured to accommodate at least a portion of at least one locking element 70 when in its locked position and when the working element 38 is attached to the tool shaft 36. In Figures 3 and 6, only the radial recess 66 on the left side of the rotating shaft 40 is visible, with the respective locking elements 70 omitted. In these embodiments, the radial recess 66 is provided on the outer circumferential surface of the second element. Alternatively, as shown in Figure 7, in another embodiment, for example, if the second element is provided with a bore 68, the radial recess 66 may be provided on the circumferential surface of the second element facing radially inward toward the rotating shaft 40, for example, on the inner circumferential surface of the bore 68.

[0077] At least one locking element 70, or at least a portion of a second element in and / or around the at least one radial recess 66, is made of a magnetic material. The other of the at least one locking element 70, or the second element in and / or around the at least one radial recess 66, is made of a magnetic or ferromagnetic material. The magnetic material may include a permanent magnet material. This results in a magnetic interaction and attractive force between the at least one locking element 70 and the at least one radial recess 66. When the working element 38 is attached to the tool shaft 36, the at least one locking element 70 automatically moves and is held in its locked position and within the at least one radial recess 66 by magnetic force, thereby mechanically engaging with the at least one radial recess 66 and thereby holding the working element 38 axially relative to the tool shaft 36.

[0078] Another advantage of the present invention is that, when the locking elements 70 are located within a hollow cylindrical jacket 78 defining an axial bore 68 configured to accommodate a cylindrical pin 64 (see Figures 3, 6, and 8), the locking elements 70 are magnetically attracted to each other even when the working element 38 is not attached to the tool shaft 36 and the cylindrical pin 64 is removed from the axial bore 68. In this case, the locking elements 70 move radially inward toward each other due to this mutual magnetic attraction. Depending on the dimensions of the locking elements 70, the retaining portion 72, and the bore 68, the locking elements 70 may even come into contact with each other.

[0079] Preferably, the locking elements 70 are held in their respective retaining parts 72 so as not to fall out into the axial bore of the first element, for example, into the axial bore 68 of the tool shaft in Figures 3 and 6 or the axial bore 68 of the extension rod 92 in Figure 8, when the working element 38 and the tool shaft 36 are separated from each other, i.e., when the cylindrical pin 64 is removed from the axial bore 68. However, when the power tool 10 and the axial retaining device 80 are used intensively, the retaining parts 72 may wear to varying degrees to the extent that one or more of the locking elements 70 are no longer properly held in their respective retaining parts 72 when the working element 38 and the tool shaft 36 are separated. This prevents one or more locking elements 70 that are no longer properly held in their retaining parts 72 from falling out of the axial bore 68 due to magnetic attraction between the locking elements 70. Rather, one or more locking elements 70 that are no longer properly held within the retaining portion 72 are held axially by one or more other locking elements 70 that are still properly held within the retaining portion 72.

[0080] This also prevents one or more locking elements 70 that are no longer properly held within their retaining portion 72 from being pushed toward the bottom of the axial bore 68 by the cylindrical pin 64 when the cylindrical pin 64 is inserted into the axial bore 68 during the process of attaching the working element 38 to the tool shaft 36.

[0081] For this purpose, it is particularly advantageous if the distal end face 82 of the cylindrical pin 64, which is inserted into the axial bore 68 when the working element 38 is attached to the tool shaft 36, has a tapered, rounded, for example, spherical, conical, or frustoconical shape. Such an end face 82 automatically pushes at least one locking element 70 radially outward into its retracted position when the cylindrical pin 64 is inserted into the axial bore 68. To facilitate the introduction of the cylindrical pin 64 into the axial bore 68, it is proposed that the outer edge 96 defining the entrance hole to the axial bore 68 has a tapered or rounded shape (see Figures 7 and 8).

[0082] Furthermore, it should be emphasized that the present invention, in particular the magnetic axial holding device 80, functions perfectly well even if the second element is not made of a magnetic or ferromagnetic material. For example, in the embodiments of Figures 3 and 6, the cylindrical pin 64 having at least one radial recess 66 can be made of plastic or aluminum. The locking elements 70 made of magnetic material are still attracted to each other radially toward the rotation axis 40 and are therefore held in their respective recesses 66 after the working element 38 has been axially mounted on the tool shaft 36. In that case, the locking elements 70 can also be made of a stronger magnetic material to generate a greater magnetic force toward each other.

[0083] The axial retaining device 80 may have individual radial recesses 66 for each locking element 70, each radial recess 66 configured to accommodate the respective locking element 70 when it is in its locked position (see Figures 3, 6, and 7). Alternatively, the axial retaining device 80 may have a single annular radial recess 66, as shown in Figure 8, which is configured to accommodate the locking elements 70 when they are all in their locked position.

[0084] As described above, as shown in Figures 3 and 6, the first element may have an axial bore 68, and at least one locking element 70 is held within a hollow cylindrical jacket 78 of the first element that radially defines the bore 68. The at least one locking element 70 moves radially inward toward the axis of rotation 40 during the transition from its retracted position to its locked position.

[0085] In response to this, the second element may have cylindrical pins 58, 64, and at least one radial recess 66 is provided on the outer surface of the pins 58, 64.

[0086] Alternatively, the second element may have an axial bore 68, and at least one radial recess 66 is provided on the inner surface of the axial bore 68.

[0087] Correspondingly, the first element may have cylindrical pins 58, 64, and at least one locking element 70 is held within the cylindrical pins 58, 64 so as to be radially movable. At least one locking element 70 moves radially outward during the transition from its retracted position to its locked position.

[0088] To transmit torque from the tool shaft 36 to the working element 38, it is proposed that the axial bore 68 and the cylindrical pin 64 each have axially extending portions 84 having corresponding non-rotating cross-sections. The portions 84 are configured to mechanically engage with each other when the working element 38 is axially mounted on the tool shaft 36, thereby enabling the transmission of torque from the tool shaft 36 to the working element 38 during the operation of the motor 24 of the power tool 10. The non-rotating cross-section may have the form of an ellipse, triangle, square, or any other type of isosceles polygon having preferably equal side lengths.

[0089] In particular, to facilitate the removal of the working element 38 from the tool shaft 36, it is proposed that, after the working element 38 is attached to the tool shaft 36, the distal end face 74 of the radially movable locking element 70 facing the second element has a tapered or rounded surface 76 (see Figure 7) to facilitate the automatic radial pushing of the locking element 70 to its retracted position when the working element 38 is removed from the tool shaft 36 and when the locking element 70 moves radially relative to at least one recess 66. Similarly, after the working element 38 is attached to the tool shaft 36, the outer edge portion 94 (see Figure 8) defining the entrance hole to at least one radially extending recess 66 facing the first element may have a tapered or rounded shape to facilitate the automatic radial pushing of the locking element 70 to its retracted position when the working element 38 is removed from the tool shaft 36.

[0090] According to a preferred embodiment, at least one locking element 70 and at least one radial recess 66 have corresponding shapes in portions that engage with each other (preferably mechanically) at least in the locked position of the locking element 70.

[0091] To uniformly distribute the holding force acting between the tool shaft 36 and the working element 38, it is proposed that when the working element 38 is attached to the tool shaft 38, the locking elements 70 are arranged equidistant in the circumferential direction around the rotation axis 40 of the tool shaft 36. Preferably, the axial holding device 80 comprises at least two, preferably at least three, and particularly preferably four locking elements 70.

[0092] The locking element 70 used in the embodiment of Figure 3 is shown in more detail in Figures 4 and 5. In particular, the locking element 70 has a rectangular parallelepiped shape, and on the rectangular surface 74 of the rectangular parallelepiped, the opposing edges 76 are tapered or rounded. Preferably, the locking element 70 is oriented within the axial locking device 80 such that the surface 74 with the rounded edges 76 faces the second element and at least one recess 66. Preferably, the rounded edges 76 of the locking element 70 face in opposite directions along the rotation axis 40 of the tool shaft 36, i.e., upward and downward in Figure 3, when the rotation axis 40 extends in the vertical direction.

[0093] Other shapes of the locking element 70 are also possible. For this purpose, the locking element 70 may be spherical, as shown in Figures 6 to 8. Thus, the retaining receiving portion 72 of the first element and at least one radial recess 66 of the second element are formed to hold the spherical locking element 70 and to accommodate a portion of the spherical locking element 70, respectively.

Claims

1. A handheld power tool (10) comprising: a tool housing (12); a motor (24) disposed therein; and a tool shaft (36) having a rotating shaft (40), wherein the tool shaft (36) is driven by the motor (24) during operation to perform rotational motion about its rotating shaft (40), and the distal end of the tool shaft (36) is accessible from the outside of the tool housing (12); and further comprising a working element (38) that is detachably attached to the distal end of the tool shaft (36) from the outside of the tool housing (12) in an axial direction parallel to the rotating shaft (40) of the tool shaft (36), and after being attached to the tool shaft (36), is held against the tool shaft (36) by an axial holding device (80), The axial holding device (80) A first element (36; 38) composed of the following elements, namely the working element (38) and the tool shaft (36), and a second element (38; 36) composed of the other of the elements, namely the working element (38) and the tool shaft (36), At least one locking element (70) is assigned to the first element (36;38) so as to be radially movable between a retracted position in which the locking element (70) is retracted into the first element (36;38) and a locked position in which the locking element (70) radially protrudes from the first element (36;38) toward the second element (38;36), At least one recess (66) assigned to the second element (38; 36) and having a radial extension, wherein the at least one radial recess (66) is configured to accommodate a portion of the at least one locking element (70) when the working element (38) is in the locked position after being attached to the tool shaft (36), and Equipped with, The following elements, namely the at least one locking element (70) and the second elements (38; 36) in and / or around the at least one radial recess (66), include a magnetic material, and the other of the elements, namely the at least one locking element (70) and the second elements (38; 36) in and / or around the at least one radial recess (66), includes a magnetic material or a ferromagnetic material, and as a result, the at least one locking element (70) automatically moves and is held in its locked position and within the at least one radial recess (66) by magnetic force after the working element (38) has been attached to the tool shaft (36), thereby engaging with the at least one radial recess (66) and holding the working element (38) axially relative to the tool shaft (36). A handheld power tool (10) characterized by the following features.

2. The power tool (10) according to claim 1, wherein the first element is the tool shaft (36) and the second element is the working element (38).

3. The power tool (10) according to claim 1, wherein the first element is the working element (38) and the second element is the tool shaft (36).

4. The power tool (10) according to any one of claims 1 to 3, wherein the first elements (36; 38) have an axial bore (68), and the at least one locking element (70) is held within a hollow cylindrical jacket (78) that radially defines the bore (68).

5. The power tool (10) according to claim 4, wherein the second element (38; 36) has a cylindrical pin (58; 64), and the at least one radial recess (66) is provided on the outer circumferential surface of the cylindrical pin (58; 64).

6. The power tool (10) according to any one of claims 1 to 3, wherein the first elements (36; 38) have cylindrical pins (58; 64), and the at least one locking element (70) is held on the outer surface of the cylindrical pins (58; 64).

7. The power tool (10) according to claim 6, wherein the second element (38; 36) has an axial bore (68), and the at least one radial recess (66) is provided on the inner surface of a hollow cylindrical jacket (78) that radially defines the bore (68).

8. The power tool (10) according to any one of claims 4 to 7, wherein the distal end (82) of the cylindrical pin (58; 64) and / or the outer edge (96) defining the entrance hole into the axial bore (68) have a tapered or rounded shape to facilitate insertion of the cylindrical pin (58; 64) into the axial bore (68) and / or to automatically push the at least one locking element (70) radially into its retracted position during insertion of the cylindrical pin (58; 64) into the axial bore (68).

9. The power tool (10) according to any one of claims 4 to 8, wherein the axial bore (68) and the cylindrical pins (58; 64) each have an axially extending portion (84) having a corresponding cross-section that is not rotationally symmetric, and the portions are configured to mechanically engage with each other after the working element (38) has been attached to the tool shaft (36), thereby enabling the transmission of torque from the tool shaft (36) to the working element (38) during the operation of the motor (24) of the power tool (10).

10. After the working element (38) is attached to the tool shaft (36), the distal end face (74) of the at least one locking element (70) facing the second element (38; 36), and / or, after the working element (38) is attached to the tool shaft (36), the outer edge (94) defining an entrance hole to the at least one recess (66) facing the first element (36; 38) has a tapered or rounded shape (76) to facilitate the automatic radial pushing of the at least one locking element (70) to its retracted position while the working element (38) is removed from the tool shaft (36).

11. The power tool (10) according to any one of claims 1 to 10, wherein the at least one locking element (70) and the at least one radial recess (66) have corresponding shapes in at least the portions thereof that engage with each other in the locked position of the at least one locking element (70).

12. The power tool (10) according to any one of claims 1 to 11, wherein the working element (38) comprises an eccentric element (54) detachably attached to the tool shaft (36) in the axial direction, and a backing pad (48) attached to the side of the eccentric element (54) opposite to the tool shaft (36) so as to be freely rotatable about a second rotation axis (60) of the backing pad (48), wherein the second rotation axis (60) extends parallel to and at a distance from the rotation axis (40) of the tool shaft (36), or the working element (38) comprises the backing pad (48) detachably attached to the tool shaft (36) in the axial direction.

13. The power tool (10) according to any one of claims 1 to 12, wherein at least two locking elements (70) are arranged at equal distances in the circumferential direction with respect to the rotation axis (40) of the tool shaft (36) after the working element (38) has been attached to the tool shaft (36), and / or the axial holding device (80) comprises preferably at least three, particularly preferably at least four locking elements (70).

14. The power tool (10) according to any one of claims 1 to 13, wherein the axial holding device (80) comprises one or more radial recesses (66) in the same number as the locking elements (70) provided on the axial holding device (80), or the axial holding device (80) comprises a single annular radial recess (66) configured to accommodate one locking element (70) or all of the locking elements (70) in their locked positions.

15. After the working element (38) is detachably attached in the axial direction to the distal end of the tool shaft (36), an axial holding device (80) for holding the working element (38) of the handheld power tool (10) in the axial direction extending parallel to the rotation axis (40) of the tool shaft (36) of the power tool (10), The axial holding device (80) A first element (36; 38) composed of the following elements, namely the working element (38) and the tool shaft (36), and a second element (38; 36) composed of the other of the elements, namely the working element (38) and the tool shaft (36), At least one locking element (70) is assigned to the first element (36;38) so as to be radially movable between a retracted position in which the at least one locking element (70) is retracted into the first element (36;38) and a locked position in which the at least one locking element (70) radially protrudes from the first element (36;38) toward the second element (38;36), At least one radial recess (66) assigned to the second element (38; 36), wherein the at least one radial recess (66) is configured to accommodate a portion of the at least one locking element (70) when it is in its locked position and after the working element (38) has been attached to the tool shaft (36), and Equipped with, The following elements, namely the at least one locking element (70) and the second elements (38; 36) in and / or around the at least one radial recess (66), include a magnetic material, and the other of the elements, namely the at least one locking element (70) and the second elements (38; 36) in and / or around the at least one radial recess (66), includes a magnetic material or a ferromagnetic material, and as a result, the at least one locking element (70) automatically moves and is held in its locked position and within the at least one radial recess (66) by magnetic force after the working element (38) has been attached to the tool shaft (36), thereby engaging with the at least one radial recess (66) and holding the working element (38) axially relative to the tool shaft (36). An axial holding device (80) characterized by the above.

16. The working element (38) of the power tool (10) is configured to be detachably attached to the distal end of the tool shaft (36) of the power tool (10) in an axial direction parallel to the rotation axis (40) of the tool shaft (36), and is further configured to be held in the axial direction relative to the tool shaft (36) by an axial holding device (80) after the working element (38) has been attached to the tool shaft (36) in the axial direction, The work element (38) comprises a first element and the second element forms part of the tool shaft (36), or the work element (38) comprises a second element and the first element forms part of the tool shaft (36), If the working element (38) is the first element, then at least one locking element (70) is assigned to the working element (38) so as to be radially movable between a retracted position in which the at least one locking element (70) is retracted into the working element (38) and a locked position in which the at least one locking element (70) protrudes radially from the working element (38) toward the tool shaft (36), and at least one radial recess (66) is assigned to the tool shaft (36) and is configured to accommodate a portion of the at least one locking element (70) when it is in the locked position and after the working element (38) has been attached to the tool shaft (36), or If the working element (38) is the second element, then at least one radially extending recess (66) is assigned to the working element (38), and the at least one radial recess (66) is configured to accommodate a portion of the at least one locking element (70), and the at least one locking element (70) is movably assigned to the tool shaft (36) between a retracted position in which the at least one locking element (70) is retracted into the tool shaft (36) and a locked position in which the at least one locking element (70) protrudes radially from the tool shaft (36) toward the working element (38) when the at least one locking element (70) is in its locked position and after the working element (38) has been attached to the tool shaft (36), The following elements, namely the at least one locking element (70) and the second elements (38; 36) in and / or around the at least one radial recess (66), include a magnetic material, and the other of the elements, namely the at least one locking element (70) and the second elements (38; 36) in and / or around the at least one radial recess (66), includes a magnetic material or a ferromagnetic material, and as a result, the at least one locking element (70) automatically moves and is held in its locked position and within the at least one radial recess (66) by magnetic force after the working element (38) has been attached to the tool shaft (36), thereby engaging with the at least one radial recess (66) and holding the working element (38) axially relative to the tool shaft (36). A work element (38) characterized by the following.

17. The work element (38) according to claim 16, comprising an eccentric element (54) detachably attached to the tool shaft (36) in the axial direction, and a backing pad (48) attached to the side of the eccentric element (54) opposite to the tool shaft (36) so as to be freely rotatable about a second rotation axis (60) of the backing pad (48), wherein the second rotation axis (60) extends parallel to and at a distance from the rotation axis (40) of the tool shaft (36), or the work element (38) comprises a backing pad (48) detachably attached to the tool shaft (36) in the axial direction.

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