Eccentric element for hand-held power tool and hand-held power tool

Abstract

The invention relates to an eccentric element (10) configured for a hand-held power tool comprising a tool motor for driving a tool shaft (16). The eccentric element (10) comprises an eccentric part (12) whose top surface (18) is connectable to the distal end (22) of the tool shaft (16) or forms an integral eccentric part therewith, a bottom surface (32) to which the working element (30) of the power tool is releasably connected so as to be freely rotatable about a second axis of rotation (34), and a counterweight part (14) connected to the eccentric part (12). The eccentric part (12) and the counterweight part (14) are separate parts and are formed such that they enter a mutual interlocking relationship when the counterweight part (14) is attached to the eccentric part (12), the interlocking relationship being at least in one direction (76; 82; 86).

Description

Technical Field

[0001] The invention relates to an eccentric element, which is configured for a hand-held power tool, the power tool comprising a tool motor for driving a tool shaft. The eccentric element is particularly configured for use in an orbital sander or polisher. The eccentric element comprises an eccentric component and a weight component, the eccentric component having a top surface, which is releasably connected or fixedly connected to the distal end of the tool shaft or forms an integral part of the tool shaft so as to transmit torque from the tool shaft to the eccentric element and to rotate the eccentric component about a first rotation axis of the eccentric component when the tool motor is activated; and a bottom surface, to which a working element of the power tool, in particular a backing plate, a sanding plate or a polishing plate, is releasably connected in a freely rotatable manner about a second rotation axis of the eccentric component, and to which the weight component is connected. Background Art

[0002] The weight component of the eccentric element can be separate from the eccentric component and attached to the eccentric component by at least one fastening element, in particular in the form of one or more screws. Alternatively, the weight component can also be formed as an integral part with the eccentric component, both parts being made of the same material and manufactured as a single integral part in a common production step.

[0003] The first and second rotation axes of the eccentric component extend parallel to and spaced apart from each other. When the top surface of the eccentric component is attached to the tool shaft of the power tool in a torque-resistant manner, and the working element is attached to the bottom surface of the eccentric component in a manner that allows it to freely rotate around the second rotation axis of the eccentric component, when the tool motor is started, the working element can perform a random orbital working motion around the first rotation axis. The eccentric element performs a rotational motion around the first rotation axis at the same speed as the tool shaft to which it is attached in a torque-resistant manner. The working element can freely rotate relative to the eccentric element around the second rotation axis. The superposition of the two motions results in a random orbital working motion of the working element. If the free rotation of the working element relative to the power tool is restricted or even completely prevented, the working element can perform an orbital (vibrating or oscillating) working motion.

[0004] The power tool has a tool housing and a motor located in the tool housing, and the motor can be driven electrically or pneumatically. After the motor is started, the motor drives the tool shaft directly or indirectly (for example, through gear transmission). The distal end of the tool shaft can protrude from the tool housing so that an eccentric element can be attached to the distal end of the tool shaft. In addition to being directly attached to the tool shaft, the eccentric element can also be attached to a component fixedly attached to the tool shaft or a component formed integrally with the tool shaft. Optionally, the eccentric component can also be formed integrally with the tool shaft or the component.

[0005] The bottom surface of the eccentric component may be provided with at least one bearing configured to receive a rotating pin in a manner that can rotate freely around the second rotation axis of the eccentric component. The distal end of the pin is configured to be releasably attached to the working element. In particular, at least one bearing is arranged in a cavity provided at the bottom surface of the eccentric element. In order to prevent at least one bearing from falling out of the cavity during the intended use of the power tool, one or more Seeger rings are provided to keep at least one bearing in an axial direction extending parallel to the second rotation axis. This results in the eccentric element being composed of a large number of parts.

[0006] Furthermore, during the intended use of the power tool, the eccentric element rotates about the first axis of rotation at a relatively high speed. Due to the large distance of the counterweight component from the first axis of rotation and the large weight, the centrifugal force acting on the counterweight component of the eccentric element is relatively large, which should be large enough to compensate for the weight of the working element and minimize vibration during the intended use of the power tool. In the case where the eccentric element and the counterweight component are two separate components connected to each other, there are relatively large centrifugal forces acting on the counterweight component, and there may be relatively large shear forces acting on any fastening elements in the eccentric element used to connect the counterweight component to the eccentric component.

[0007] In addition to the centrifugal force acting in the radial direction, there may be other forces, such as forces acting in the circumferential direction when the eccentric element is accelerated (positive and negative). In order to avoid safety problems during the use of the power tool, at least one fastening element must be designed to be very strong, which makes the fastening element and the entire eccentric element large, bulky and heavy. Summary of the invention

[0008] An object of the present invention is to overcome the above-mentioned disadvantages of known eccentric elements. This object is solved by an eccentric element comprising the features of claim 1. In particular, based on an eccentric element of the above-mentioned type, it is proposed that the eccentric part and the weight part are separate parts and are formed so that when the weight part is attached to the eccentric part, they enter into a mutually interlocking relationship, the interlocking relationship being effective in at least one direction.

[0009] The idea of ​​the invention is that, during the intended use of the power tool, a reduction in the forces in the two parts of the eccentric element is achieved at least in one direction, solely by means of the interlocking of the two parts, so that one or more fastening elements can be designed to have smaller dimensions or can be completely omitted. This results in the eccentric element consisting of fewer parts and being designed to be smaller and lighter.

[0010] Preferably, when the two parts of the eccentric element are brought into interlocking relationship, the two parts are also attached to each other by a press-fit connection. This requires that the eccentric part and the counterweight part are manufactured with particularly high precision, at least in the area where they realize the interlocking relationship and the press-fit connection, but on the other hand it has the following advantages: separate fastening means, such as screws or the like, can be completely omitted.

[0011] The two-part eccentric element has the advantage that waste material generated during the manufacturing process (e.g. by milling) can be reduced. When manufacturing a single large eccentric element, the eccentric part and the counterweight part are manufactured as one common part, which generates more waste material than when two smaller parts are manufactured and then connected to each other. The invention solves the long-standing problem of fastening two parts together in a particularly effective and safe and reliable manner.

[0012] For the purposes of the present invention, when the eccentric component and the counterweight component are in a mutually interlocking relationship, this means that they engage and support each other so that they are firmly in contact with each other in at least one direction. To this end, the two components have corresponding undercut portions that engage with each other as part of the attachment of the counterweight component to the eccentric component. The undercut portions each have at least one adjacent wall. When the two components are engaged with each other, the corresponding adjacent walls of the undercut portions of the two components abut each other in the abutment direction as part of the attachment of the components to each other, and the adjacent walls abut each other at least regionally, preferably extending along their entire surface. The adjacent walls prevent further relative movement of the components in the abutment direction.

[0013] Preferably, the adjoining walls have a corresponding shape and extension so as to abut each other along their entire surface extension. The surface extension may be flat or curved, the curvature being two-dimensional around a single axis (e.g. corresponding to a cylindrical surface) or three-dimensional around two axes (e.g. corresponding to a spherical surface). However, the surface extension may also be any free-form surface. The adjoining walls may have positioning means (e.g. at least one protrusion on one wall and at least one corresponding recess on the other wall) which may engage with each other when the two parts are connected to each other so as to position the two parts relative to each other. Positioning may be performed in two or three dimensions.

[0014] If the undercut portions of the two components each have a plurality of abutment walls at an angle (not equal to 0° and 180°), preferably a right angle (90°), then the corresponding abutment walls of the two components then abut each other at a respective angle (e.g. 90°) in a plurality of abutment directions. The abutment walls prevent further movement of the components relative to each other in a plurality of abutment directions. Of course, by means of two abutment walls extending at an angle relative to each other, further movement of the components relative to each other in a plurality of other directions within an angle between the two abutment directions can also be prevented.

[0015] For example, if the undercut portions of the two components each have corresponding adjacent walls that are at an angle of 90° to each other, further relative movement of the two components relative to each other in two adjacent directions that are perpendicular to each other can be prevented, for example in a first direction extending radially outward relative to the second rotation axis and in a second circumferential direction extending clockwise (or counterclockwise) around the second rotation axis.

[0016] According to one embodiment of the present invention, the interlocking relationship between the eccentric component and the counterweight component can act radially relative to the first rotation axis of the eccentric component at least during the start-up of the tool motor and the rotation of the eccentric element around the first rotation axis. In this embodiment, the interlocking relationship between the eccentric component and the counterweight component is used to reduce the centrifugal force acting during the rotation of the eccentric element around the first rotation axis. Preferably, the interlocking relationship only acts in the radially outward direction and provides force reduction. Therefore, when a radially outward force relative to the eccentric component is applied to the counterweight component due to the centrifugal force, the interlocking relationship between the two components prevents the counterweight component from moving radially outward relative to the eccentric component. However, the interlocking relationship can be designed so that: when the counterweight component moves radially inward in the opposite direction (or moves in any other direction other than radially outward), the interlocking relationship can be released and the counterweight component can be disengaged from the eccentric component.

[0017] According to another embodiment of the present invention, the interlocking relationship between the eccentric component and the counterweight component can act in a circumferential direction relative to the first rotation axis of the eccentric component. In this embodiment, the interlocking relationship between the eccentric component and the counterweight component is used to reduce the force acting during acceleration and / or braking of the eccentric element. However, the interlocking relationship can be designed so that: when the counterweight component moves in another direction other than the centrifugal direction relative to the eccentric component, the interlocking relationship can be released and the counterweight component can be separated from the eccentric component.

[0018] According to another embodiment of the present invention, the interlocking relationship between the eccentric component and the counterweight component can act in an axial direction extending parallel to the first rotation axis of the eccentric component. In this embodiment, the interlocking relationship between the eccentric component and the counterweight component is used to alleviate the axial force acting during the slow rotation or stationary period of the eccentric element due to gravity. However, the interlocking relationship can be designed so that: when the counterweight component moves relative to the eccentric component in another direction other than the axial direction, the interlocking relationship can be released and the counterweight component can be separated from the eccentric component.

[0019] Furthermore, the interlocking relationship between the eccentric component and the counterweight component can be designed so that: not only one or more forces acting in at least one direction are mitigated, but also torque about at least one axis can be received and absorbed. For example, during acceleration and braking of the eccentric element, torque about the first axis of rotation can act between the eccentric component and the counterweight component. The interlocking relationship between the eccentric component and the counterweight component can be designed so that: torque is received and absorbed during acceleration or during braking or during acceleration and braking of the eccentric element.

[0020] It is suggested that once the eccentric component is attached to the tool shaft, the first rotation axis of the eccentric component corresponds to the rotation axis of the tool shaft. Additionally or alternatively, once the working element is attached to the eccentric component, the second rotation axis of the eccentric component may correspond to the rotation axis of the working element. Preferably, the first rotation axis and the second rotation axis of the eccentric component extend parallel to each other and are spaced apart.

[0021] According to a preferred embodiment of the invention, it is proposed that the eccentric element comprises at least one fastening element, in particular a screw, which is configured to hold the weight component in a mutually interlocking relationship relative to the eccentric component before, during and after activation of the tool motor. Preferably, the fastening element acts on the weight component and holds the weight component relative to the eccentric component in an axial direction extending substantially parallel to the first rotation axis.

[0022] According to another preferred embodiment of the present invention, it is suggested that the eccentric element comprises at least one bearing, which is associated with the bottom surface of the eccentric component and is configured to receive a rotating pin in a manner that can rotate freely around the second rotation axis of the eccentric component, wherein the distal end of the pin is configured to be releasably attached to the working element. Preferably, at least one bearing is located in a groove provided in the bottom surface of the eccentric component and has a cylindrical shape. The rotation axis of the bearing corresponds to the second rotation axis of the eccentric component. The rotating pin can be axially retained in at least one bearing by a press-fit connection or in any other manner (e.g., gluing, welding, clamping, ratchet connection, etc.). The working element can be attached to the distal end of the rotating pin by a threaded connection or in any other manner.

[0023] For example, the working element (e.g., in the form of a backing plate, a grinding plate, or a polishing plate) may have a threaded rod that can be screwed into a corresponding threaded hole at the distal end of the rotating pin. Alternatively, the working element (e.g., in the form of a backing plate, a grinding plate, or a polishing plate) may have a threaded hole that is suitable for receiving a corresponding threaded rod at the distal end of the rotating pin, and the threaded rod can be screwed into the threaded hole.

[0024] According to another embodiment, it is suggested that the distal end of the rotating pin includes a head, the diameter of the head is larger than the portion of the rotating pin received in at least one bearing, and the head has a non-rotationally symmetrical outer peripheral surface. The head is configured to be received by a corresponding cavity or groove provided in the working element, and the cavity or groove has an inner peripheral surface corresponding to the outer peripheral surface of the head. After the head is inserted into the corresponding cavity or groove, the working element is preferably axially fixed to the rotating pin by a fastening element (in particular a screw). By axially inserting the head into the cavity or groove, a torque-resistant connection in a plane extending perpendicular to the second rotation axis is provided. Insertion / removal of the head into / out of the cavity or groove is performed in the axial direction. After insertion and before removal, the fastening element fixes the working element axially relative to the distal end of the rotating pin.

[0025] According to another preferred embodiment, it is suggested that: after the weight component is attached to the eccentric component, the portion of the weight component facing the second rotation axis of the eccentric component holds at least one bearing in the axial direction relative to the eccentric component. Preferably, the portion of the weight component facing the second rotation axis holds at least one bearing in a cavity or groove provided in the bottom surface of the eccentric component. Therefore, attaching the weight component to the eccentric component not only provides an interlocking relationship between the two components, but also fixes at least one bearing in / at the eccentric component. No additional components (such as Seeger rings, etc.) are required to fix at least one bearing in the axial direction relative to the eccentric component. The total number of parts included in the eccentric element can be further reduced, which has advantages in terms of the manufacture of the eccentric element and the compact and lightweight design.

[0026] It is further suggested that the top surface of the eccentric component includes a threaded hole, the longitudinal axis of which corresponds to the first rotation axis of the eccentric component, and the hole is configured to receive the threaded distal end of the tool shaft, or the threaded distal end of the tool shaft fixedly attached to the tool shaft, or the threaded distal end of a component formed integrally therewith, for releasable threaded connection.

[0027] Preferably, the second rotation axis extends through the center of gravity of the eccentric component. This can also be the center of gravity of the entire eccentric element with the counterweight component and the working element attached to the eccentric component. The first rotation axis extends eccentrically relative to the center of gravity. However, in alternative embodiments, it is also possible that the first rotation axis extends through the center of gravity of the eccentric component and the eccentric element, respectively, and the second rotation axis extends eccentrically relative to the center of gravity.

[0028] According to a preferred embodiment of the invention, it is proposed that in a plan view parallel to the first and / or second rotation axis of the eccentric member, the eccentric member has a circular shape and the second rotation axis forms the center of the circular shape or the center axis of the eccentric member.

[0029] According to another preferred embodiment, in a bottom view parallel to the first and / or second rotation axis of the eccentric component, the counterweight component has a circular or sector shape, wherein the center or the central axis of the circle or sector of the counterweight component is spaced from the second rotation axis, respectively. Preferably, the center of the circle or sector or the central axis of the counterweight component is also spaced from the first rotation axis, respectively.

[0030] Preferably, the weight component or its center of gravity is located on one side of the first rotation axis, opposite to the second rotation axis. In other words, relative to the first rotation axis, the weight component is located opposite to the working element, which is attached to the eccentric component at the second rotation axis. In this way, the weight component can optimally compensate for the eccentricity caused by the working element.

[0031] It is suggested that the first rotation axis extends through an imaginary straight line connecting the center of the circle or sector of the weight element and the second rotation axis. Thus, the weight element or its center of gravity is located on one side of the first rotation axis, diametrically opposite the second rotation axis.

[0032] Preferably, the eccentric component is made of metal, in particular steel or aluminum, or of a plastic material with a metal insert. In particular, the metal insert can be arranged near or around a first rotation axis, wherein the eccentric component is attached to the distal end of the tool shaft or to a component connected to the tool shaft or a component formed integrally therewith, and / or near or around a second rotation axis, wherein the working element is attached to the eccentric component in a freely rotatable manner about the second rotation axis. The metal insert near or around the first rotation axis can be designed as a hollow cylinder or cylindrical bushing with an internal thread, into which the threaded distal end of the tool shaft or component is screwed. The metal insert located near or around the second rotation axis can be designed as a hollow cylinder or cylindrical bushing, into which at least one bearing for a rotating pin can be inserted. One or more metal inserts can be inserted into the plastic material after the plastic material is manufactured, for example, by pressing the insert into a corresponding groove in the plastic material. Alternatively, one or more metal inserts can be provided in the plastic material during the plastic material manufacturing process, for example, by a co-molding process, in which heated plastic material is injected around the insert.

[0033] The weight component can also be made of plastic material. In order to achieve the required weight to achieve the vibration reduction function, a metal insert can be arranged in the plastic material, the metal insert preferably being made of solid metal material. According to another preferred embodiment, the weight component is made of metal, in particular steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Other features and advantages of the present invention will become clearer based on the following description of preferred embodiments and the accompanying drawings. It should be emphasized that each feature shown in the drawings may be important to the present invention in itself, even if it is not explicitly mentioned in the description and / or shown in the drawings. In addition, different features shown in the same or different figures may be important to the present invention in any combination, even if the combination is not explicitly mentioned in the description and / or shown in the drawings.

[0035] The attached figure shows:

[0036] Figure 1 is a top perspective view of an eccentric element according to a first embodiment of the present invention;

[0037] Figure 2 for Figure 1 Bottom perspective view of the middle eccentric element;

[0038] Figure 3 for Figure 1 and Figure 2 Sectional view of the middle eccentric element along the vertical section;

[0039] Figure 4 for Figures 1 to 3 A bottom view of the eccentric element in FIG.

[0040] Figure 5 for Figures 1 to 4 A top view of the eccentric element in FIG.

[0041] Figure 6 is a bottom view of an eccentric element according to a second embodiment of the present invention;

[0042] Figure 7 FIG. 4 is a cross-sectional view of an eccentric element according to a third embodiment of the present invention along a vertical section.

[0043] Figure 8 It is an enlarged view of an embodiment of the mutual locking relationship between the eccentric component and the counterweight component of the eccentric element according to the present invention.

[0044] Fig. 9 It is a bottom view of an eccentric element known in the prior art. DETAILED DESCRIPTION

[0045] All figures show an eccentric element 10 which consists of two separate parts connected to each other. The two parts include an eccentric part 12 and a weight part 14. The eccentric part 12 is provided on a top surface 18 of the eccentric part 12 to a tool shaft 16 (see FIG. 1 ) of a power tool (not shown). Figure 3 ) connection. The connection is preferably releasable. Figures 1 to 8In the embodiment shown, the top surface 18 is provided with a connecting element 20, to which the distal end 22 of the tool shaft 16 is connected. In the embodiment shown, the connecting element 20 has the form of a threaded hole 24. The longitudinal axis 26 of the threaded hole 24 coincides with the first rotation axis 28 of the eccentric component 12. The threaded distal end 22 of the tool shaft 16 can be screwed into the threaded hole 24. When the tool shaft 16 is rotated about the first rotation axis 28, for example by an electric or pneumatic motor (not shown) of a power tool, torque is transmitted to the eccentric component 12 and the entire eccentric element 10, respectively.

[0046] In addition, the eccentric component 12 provides a working element 30 (see Figure 3 ), the working element 30 is, for example, in the form of a backing plate, a grinding plate or a polishing plate, and the working element 30 is attached to the bottom surface 32 of the eccentric component 12 in a manner that it can rotate freely around the second rotation axis 34. Figure 3 The schematic diagram in shows a working element 30 in the form of a back plate. The attachment and the rotation of the working element 30 about the second axis of rotation 34 can be realized in a number of possible ways. Figures 1 to 8 A preferred embodiment for attaching and rotating the working element 30 is shown, however, it may be replaced by other ways of attaching the working element 30 to the eccentric component 12 in a freely rotatable manner.

[0047] exist Figures 1 to 8 In a preferred embodiment of the eccentric element 10, the eccentric element 10 comprises at least one bearing 36, which is associated with the bottom surface 32 of the eccentric component 12 and is configured to receive a rotating pin 38 in a freely rotatable manner about the second rotation axis 34 of the eccentric component 12. The distal end 40 of the pin 38 is configured to be releasably attached to the working element 30. Preferably, the at least one bearing 36 is located in a groove 42 provided in the bottom surface 32 of the eccentric component 12, and the at least one bearing 36 has a cylindrical shape when viewed from above or below. The rotation axis 44 of the bearing 36 corresponds to the second rotation axis 34 of the eccentric component 12. The rotating pin 38 can be axially retained in the at least one bearing 36 by a press-fit connection or any other means (e.g., gluing, welding, clamping, snap-in connection, etc.). The working element 30 can be attached to the distal end 40 of the rotating pin 38 by a threaded connection or any other means.

[0048] For example, in an embodiment not shown in the figures, the working element 30 (e.g., in the form of a backing plate, a grinding plate, or a polishing plate) may have a threaded rod that can be screwed into a corresponding threaded hole provided at the distal end 40 of the rotating pin 38. Alternatively, in another embodiment not shown in the figures, the working element 30 (e.g., in the form of a backing plate, a grinding plate, or a polishing plate) may have a threaded hole that is suitable for receiving a corresponding threaded rod formed at the distal end 40 of the rotating pin 38 and screwed into the threaded hole.

[0049] according to Figures 1 to 8 In the illustrated embodiment, it is suggested that the distal end 40 of the rotation pin 38 includes a head portion 46 having a diameter greater than the portion 48 of the rotation pin 38 received in the at least one bearing 36 (see Figure 3 and Figure 7 ), and having a non-rotationally symmetrical outer peripheral surface 50 (see Figure 2 , Figure 4 and Figure 6 ). The head portion 46 is configured to be received by a corresponding cavity or groove 52 provided in a top surface 54 of the working element 30, the cavity or groove 52 having an inner peripheral surface 56 corresponding to the outer peripheral surface 50 of the head portion 46. After the head 38 is inserted into the corresponding cavity or groove 52, the working element 30 is preferably axially fixed to the rotation pin 38 by a fastening element 58, in particular a screw. The screw 58 can be screwed into a corresponding threaded hole 59 located at the distal end 40 of the rotation pin 38. By axially inserting the head 38 into the cavity or groove 52, a torque-resistant connection in a plane extending perpendicular to the second rotation axis 34 is provided. Insertion / removal of the head 38 into / from the cavity or groove 52 is performed in the axial direction. After insertion and before removal, the fastening element 58 fixes the working element 30 axially relative to the distal end 40 of the rotation pin 38.

[0050] Shown as an example of a working element Figure 3 The back plate 30 in the embodiment includes an attachment surface 60 located on its bottom surface. A polishing or grinding member (not shown) can be releasably attached to the attachment surface 60. To this end, the polishing or grinding member can include a corresponding attachment surface on its top surface. The attachment surface 60 and the corresponding attachment surface on the top surface of the polishing or grinding member can each include a hook and loop connection surface of a hook and / or loop. The polishing member can include a polishing pad, which is made of or includes foam, wool, microfiber, etc. The grinding member can include a grinding plate, such as sandpaper or emery cloth.

[0051] The weight component 14 and the eccentric component 12 are two separate components which are connected to one another during the manufacture of the eccentric element 10. In particular, it is proposed that the two components 12, 14 are connected to one another by means of a separate fastening element, in particular in the form of a screw 62. Of course, other ways of connecting the two components 12, 14 are also conceivable. The screw 62 can be guided through a corresponding opening 64 in the weight component 14 (see Figure 3 and 7 ) and screwed into the corresponding internal threaded hole 66 in the eccentric component 12.

[0052] In order to reduce the total number of individual components of the eccentric element 10 and to provide a more compact and lightweight eccentric element 10, the present invention (see Figures 1 to 8) suggests that the eccentric member 12 and the weight member 14 are separate components and are formed so that when the weight member 14 is attached to the eccentric member 12, they enter into a mutually interlocking relationship that acts in at least one direction.

[0053] The idea of ​​the invention is to achieve a reduction in force in at least one direction during the intended use of the power tool or the eccentric element 10, respectively, so that one or more fastening elements 62 can be designed with smaller dimensions or they can be completely omitted (see Figure 6 ). This allows the eccentric element 10 to be composed of fewer parts and designed to be smaller and lighter.

[0054] For the purposes of the present invention, when the eccentric component 12 and the weight component 14 are in an interlocking relationship with each other, this means that they engage and support each other so that they are firmly in contact with each other in at least one direction. To this end, both components have corresponding undercut portions 68, 70 (see Figure 8 ), the undercut portions 68, 70 engage each other as part of the attachment of the weight component 14 to the eccentric component 12. The undercut portions 68, 70 each have at least one abutment wall 72, 74 (see Figure 8 ). The corresponding abutment walls 72, 74 of the undercut portions 68, 70 of the two components 12, 14 abut each other in an abutment direction (i.e., the counterweight component 14 moves relative to the eccentric component 12 in the abutment direction 76; or the eccentric component 12 moves relative to the counterweight component 14 in the opposite abutment direction) as part of the interconnection of the components 12, 14. When the components 12, 14 are engaged with each other, the abutment walls 72, 74 abut each other at least in area, preferably extending along their entire surface. The abutment walls 72, 74 prevent the components 12, 14 from further relative movement in the abutment direction 76.

[0055] Preferably, the adjoining walls 72, 74 have corresponding shapes and extensions so as to abut each other along their entire surface extension. The surface extension may be flat or curved, the curvature being two-dimensional about one or more parallel axes (e.g. corresponding to a cylindrical or elliptical surface) or three-dimensional about two intersecting axes (e.g. corresponding to a spherical or ellipsoidal surface). However, the surface extension may also be any free-form surface. The adjoining walls 72, 74 may have positioning means (e.g. at least one protrusion on one wall 72; 74 and at least one corresponding recess on the other wall 74; 72), which may engage with each other when the two components 12, 14 are connected to each other so as to position the two components 12, 14 relative to each other and possibly also maintain them (e.g. by a press-fit connection). The positioning may be achieved in two or three dimensions.

[0056] If the undercuts 68, 70 of the two components 12, 14 have a plurality of corresponding abutment walls 72, 74 (acting in a radial direction 76 relative to the second rotation axis 34); 78, 80 (acting in a circumferential direction 82 about the second rotation axis 34), and these abutment walls are at an angle (not equal to 0° and 180°), preferably at right angles (see Figure 6 ), the corresponding adjacent walls 72, 74; 78, 80 of the two components 12, 14 then abut each other at corresponding angles (e.g. 90°) along a plurality of adjacent directions 76, 82. Of course, the adjacent walls 78, 80 can also be designed to act in a circumferential direction 82 about the first rotation axis 28. The adjacent walls 72, 74; 78, 80 prevent the components 12, 14 from further moving relative to each other in a plurality of adjacent directions 76, 82. By means of two or more adjacent walls 72, 74; 78, 80 extending at a certain angle relative to each other, the components 12, 14 can also be prevented from further moving relative to each other in a plurality of other directions within an angle between the two adjacent directions 76, 82.

[0057] Preferably, the two components 12, 14 are attached to each other in a press-fit connection, thereby holding the weight component 14 relative to the eccentric component 12. One or more fastening elements 62 may be provided, for example each fastening element comprising a screw, to secure the weight component 14 relative to the eccentric component 12 only in an axial direction 86 extending substantially parallel to the first rotation axis 28, in order to prevent the two components 12, 14 from accidentally loosening and separating during the intended use of the eccentric element 10.

[0058] It is contemplated that the eccentric element 10 includes more than one weight component 14 attached to the eccentric component 12. Preferably, two separate weight components 14 are attached to radially opposite sides of the eccentric component 12. Furthermore, preferably, the two separate weight components 14 are attached to the eccentric component 12 at different heights in the axial direction. Even further, preferably, the two separate weight components 14 have different weights in order to compensate not only for forces but also for torques caused by the working element 30 eccentrically attached to the eccentric component 12 relative to the first rotation axis 28.

[0059] For example, if the undercut portions 68, 70 of the two components 12, 14 have two respective abutment walls 72, 78; 74, 80, respectively, which are at an angle of 90° to each other, then further relative movement of the two components 12, 14 relative to each other in two mutually perpendicular abutment directions 76, 82 will be prevented, for example in a first direction 76 extending radially outwardly relative to the second rotation axis 34 and in a second circumferential direction 82 extending clockwise (or counterclockwise) about the second rotation axis 34 (see Figure 6 ).

[0060] according to Figure 3and Figure 8 In one embodiment of the invention shown, the interlocking relationship between the eccentric component 12 and the weight component 14 acts in a radial direction 76 relative to the first or second axis of rotation 28, 34 of the eccentric component 12, at least during the start of the tool motor and the rotation of the eccentric element 10 about the first axis of rotation 28. In this embodiment, the interlocking relationship between the eccentric component 12 and the weight component 14 is used to reduce the centrifugal force acting during the rotation of the eccentric element 10 about the first axis of rotation 28. Preferably, the interlocking relationship acts only in the radially outward direction 76 and provides force reduction. To this end, a gap 84 is provided between the outer peripheral surface of the eccentric component 12 and the opposite surface of the weight component 14 (which faces the outer peripheral surface of the eccentric component 12). Therefore, when the weight component 14 is subjected to a radially outward force relative to the eccentric component 12 due to the centrifugal force, the interlocking relationship between the two components 12, 14 prevents the weight component 14 from moving radially outward relative to the eccentric component 12. The interlocking relationship may be designed such that when the weight component 14 is slightly moved radially inward in the opposite direction to reduce the width of the gap 84 (or in any other direction other than radially outward), the interlocking relationship may be released and the weight component 14 may be separated from the eccentric component 12 .

[0061] according to Figure 6 In another embodiment of the present invention shown, the interlocking relationship between the eccentric component 12 and the weight component 14 acts in a circumferential direction 82 relative to the first or second rotation axis 28, 34 of the eccentric component 12. In this embodiment, the interlocking relationship between the eccentric component 12 and the weight component 14 is used to mitigate the forces acting during acceleration and / or braking of the eccentric element 10. The interlocking relationship can be designed so that: when the weight component 14 moves relative to the eccentric component 12 in another direction other than the centrifugal direction, in particular when it moves radially inwardly toward the eccentric component 12, the interlocking relationship can be released and the weight component 14 can be separated from the eccentric component 12. Figure 6 In the embodiment of FIG. 8 , the interlocking relationship operates in the circumferential direction 82 as well as in the radial direction 76 .

[0062] according to Figure 7 In another embodiment of the present invention shown, the interlocking relationship between the eccentric component 12 and the weight component 14 acts in an axial direction 86 extending parallel to the first and second rotational axes 28, 34 of the eccentric component 12. In this embodiment, the interlocking relationship between the eccentric component 12 and the weight component 14 is used to alleviate the axial force acting during slow rotation or stationary state of the eccentric element 12 due to gravity. The interlocking relationship can be designed so that: when the weight component 14 moves relative to the eccentric component 12 in another direction other than the axial direction 86, the interlocking relationship can be released and the weight component 14 can be separated from the eccentric component 12. Figure 7In the embodiment of FIG. 8 , the interlocking relationship acts in both the axial direction 86 and the radial direction 76 .

[0063] The interlocking relationship between the eccentric component 12 and the weight component 14 may be designed to not only mitigate one or more forces acting in at least one direction 76; 82; 86, but also receive and absorb torque about at least one axis.

[0064] Once the eccentric member 12 is attached to the tool shaft 16, the first rotational axis 28 of the eccentric member 12 may correspond to the rotational axis of the tool shaft 16. Once the working element 30 is attached to the eccentric member 12, the second rotational axis 34 of the eccentric member 12 may correspond to the rotational axis of the working element 30. Preferably, the first and second rotational axes 28, 34 of the eccentric member 12 extend parallel to each other and are spaced apart from each other to achieve random orbital working motion of the working element 30 during start-up of the tool motor and intended use of the power tool.

[0065] As previously mentioned, the eccentric element 12 may include at least one fastening element 62, in particular a screw, which is configured to hold the weight component 14 in an interlocking relationship relative to the eccentric component 12 before, during and after activation of the tool motor. Preferably, the fastening element 62 acts in an axial direction 86 extending substantially parallel to the first rotation axis 28 and holds the weight component 14 relative to the eccentric component 12.

[0066] exist Fig. 9 In the prior art eccentric element 10 shown, a Seeger ring 88 can be seen for fixing the bearing 36 in the groove 42 provided in the bottom surface 32 of the eccentric member 12. One of the advantages of the present invention is that such a Seeger ring 88 can be omitted, which will be explained in further detail below.

[0067] like Figure 3 , 7 As shown in Figures 8 and 9, after the weight component 14 (particularly a portion of the undercut portion 70 of the weight component 14) is attached to the eccentric component 12, the portion of the weight component 14 facing the second rotational axis 34 of the eccentric component 12 retains the at least one bearing 36 in the axial direction 86 relative to the eccentric component 12. Preferably, the portion of the weight component 14 facing the second rotational axis 34 retains the at least one bearing 36 in the cavity or recess 42 provided in the bottom surface 32 of the eccentric component 12. Therefore, the attachment of the weight component 14 to the eccentric component 12 not only provides an interlocking relationship between the two components 12, 14, but also fixes the at least one bearing 36 in / at the eccentric component 12. No additional components, such as Seeger rings 88 (see Figure 8) are required. Fig. 9) or similar devices to fix at least one bearing 36 relative to the eccentric component 12 in the axial direction 86. In this way, the total number of parts constituting the eccentric element 10 can be further reduced, which has advantages in terms of the manufacture of the eccentric element 10 and in terms of compact and lightweight design.

[0068] The second rotation axis 34 can extend through the center of gravity of the eccentric component 12 or through the center of gravity of the entire eccentric element 10 with the weight component 14 and the working element 30 attached to the eccentric component 12. The first rotation axis 28 can extend eccentrically relative to the center of gravity. However, the first rotation axis 28 can also extend through the center of gravity of the eccentric component 12 or the center of gravity of the eccentric element 10, respectively, and the second rotation axis 34 extends eccentrically relative to this center of gravity.

[0069] In a top view parallel to the first and / or second rotation axis 28, 34 of the eccentric element 12, the eccentric element 12 can have a circular shape (see Figure 5 ), wherein the second rotation axis 34 forms the center of the circular shape or the center axis of the eccentric component 12 (see Figure 4 and 6 ).

[0070] In a bottom view parallel to the first and / or second rotation axis 28, 34 of the eccentric component 12, the weight component 14 can have a circular or sector shape (see Figure 4 and Figure 6 ), wherein the geometric center or central axis 90 of the circle or sector of the weight component 14 is respectively spaced apart from the second rotation axis 34. Preferably, the center or central axis 90 of the circle or sector of the weight component 14 is also respectively spaced apart from the first rotation axis 28 (see Figure 5 ).

[0071] The weight component 14 or its center axis 90 is respectively located on one side of the first rotation axis 28 opposite to the second rotation axis 34. In other words, the weight component 14 is arranged opposite to the working element 30 with respect to the first rotation axis 28, and the working element 30 is attached to the eccentric component 12 at the second rotation axis 34. In this way, during the intended use of the power tool, the eccentricity caused by the working element 30 can be optimally compensated by the weight component 14.

[0072] The first axis of rotation 28 may extend through an imaginary straight line 92 (see FIG. 1 ) connecting a center or central axis 90 of a circle or sector of the weight component 14 and the second axis of rotation 34. Figure 5 ). Therefore, the weight component 14 or its central axis 90 is located on one side of the first rotation axis 28 and radially opposite to the second rotation axis 34.

[0073] The eccentric component 12 can be made of metal, in particular steel or aluminum, or of a plastic material with a metal insert (not shown in the figures). In particular, the metal insert can be arranged near or around the first rotation axis 28 or the connecting element 20, wherein the eccentric component 12 is connected to the distal end 22 of the tool shaft 16 or to a component that is connected to the tool shaft 16 or is formed integrally therewith. An insert can also be arranged near or around the second rotation axis 34 or a bearing 36 with a rotating rod 38, respectively, wherein the working element 30 is attached to the eccentric component 12 in a freely rotatable manner about the second rotation axis 34. The metal insert near or around the first rotation axis 28 can be designed as a hollow cylinder or cylindrical bushing with an internal thread, into which the threaded distal end 22 of the tool shaft 16 is screwed. The metal insert near or around the second rotation axis 34 can be designed as a hollow cylinder or cylindrical bushing, into which at least one bearing 36 for a rotating pin 38 is inserted. One or more metal inserts can be inserted into the plastic material after it has been manufactured, for example by pressing the insert into a corresponding groove in the plastic material. Alternatively, one or more metal inserts may be provided in the plastics material during manufacture, for example by a co-moulding process in which heated plastics material is injected around the inserts.

[0074] The weight component 14 is preferably made of metal, in particular steel or aluminum. However, it can also be made of plastic material. In order to achieve the required weight to achieve the vibration reduction function, a metal insert can be arranged in the plastic material, preferably made of solid metal material.

Claims

1. An eccentric element (10) configured for a handheld power tool, the power tool comprising a tool motor for driving a tool shaft (16), the eccentric element (10) comprising: An eccentric member (12) comprising a top surface (18) which is releasably or fixedly connected to a distal end (22) of a tool shaft (16) or forms an integral part of the tool shaft (16) so as to transmit torque from the tool shaft (16) to the eccentric element (10) and to rotate the eccentric member (12) about a first rotation axis (28) of the eccentric member (12) when the tool motor is activated, a bottom surface (32) to which a working element (30) of the power tool is releasably connected in such a way that it can rotate freely about a second rotation axis (34) of the eccentric member (12), and a counterweight member (14) attached to the eccentric member (12), It is characterized in that The eccentric component (12) and the weight component (14) are separate components and are formed so that when the weight component (14) is attached to the eccentric component (12) they enter into an interlocking relationship that operates in at least one direction (76; 82; 86).

2. The eccentric element (10) according to claim 1, wherein: The interlocking relationship between the eccentric member (12) and the counterweight member (14) operates in a radial direction (76) relative to a first axis of rotation (28) of the eccentric member (12), at least during activation of the tool motor.

3. The eccentric element (10) according to claim 2, wherein: The interlocking relationship between the eccentric member (12) and the counterweight member (14) operates in a circumferential direction (82) relative to a first or second axis of rotation (28; 34) of the eccentric member (12).

4. The eccentric element (10) according to any one of the preceding claims 1 to 3, wherein: The interlocking relationship between the eccentric member (12) and the counterweight member (14) operates in an axial direction (86) extending parallel to a first or second axis of rotation (28; 34) of the eccentric member (12).

5. The eccentric element (10) according to any one of the preceding claims 1 to 3, wherein: Once the eccentric component (12) is attached to the tool shaft (16), the first rotation axis (28) of the eccentric component (12) corresponds to the rotation axis of the tool shaft (16), and / or, once the working element (30) is attached to the eccentric component (12), the second rotation axis (34) of the eccentric component (12) corresponds to the rotation axis of the working element (30).

6. The eccentric element (10) according to any one of the preceding claims 1 to 3, wherein: The eccentric member (10) includes at least one securing member (62) configured to retain the counterweight member (14) relative to the eccentric member (12) in their interlocked relationship before, during and after activation of the tool motor.

7. The eccentric element (10) according to claim 6, wherein: The at least one fastening element (62) is a screw.

8. The eccentric element (10) according to any one of the preceding claims 1 to 3, wherein: The eccentric element (10) includes at least one bearing (36) associated with a bottom surface (32) of the eccentric component (12) and configured to receive a swivel pin (38) in a manner that allows free rotation about a second rotation axis (34) of the eccentric component (12), wherein a distal end (40) of the swivel pin (38) is configured to be releasably attached to the working element (30).

9. The eccentric element (10) according to claim 8, wherein: The distal end (40) of the rotating pin (38) includes a head portion (46) having a larger diameter than a portion (48) of the rotating pin (38) received in at least one bearing (36) and having a non-rotationally symmetrical outer peripheral surface (50), the head portion (46) being configured to be received by a corresponding cavity (52) provided in the working element (30), and the corresponding cavity (52) having an inner peripheral surface (56) corresponding to the outer peripheral surface (50) of the head portion (46), and wherein the working element (30) is axially fixed to the rotating pin (38) by a fastening element (58).

10. The eccentric element (10) according to claim 9, wherein: The fastening element (58) is a screw.

11. The eccentric element (10) according to claim 9, wherein: After attachment to the eccentric member (12), a portion of the weight member (14) facing the second rotational axis (34) of the eccentric member (12) holds the at least one bearing (36) in an axial direction relative to the eccentric member (12).

12. The eccentric element (10) according to any one of the preceding claims 1 to 3, wherein: The top surface (18) of the eccentric component (12) includes a threaded hole (24), the longitudinal axis (26) of the hole (24) corresponds to the first rotation axis (28) of the eccentric component (12), and the hole (24) is configured to receive the threaded distal end (22) of the tool shaft (16) or a component fixedly attached to the tool shaft (16) or formed integrally therewith for releasable threaded attachment.

13. The eccentric element (10) according to any one of the preceding claims 1 to 3, wherein: In a top view parallel to the first and / or second rotation axis (28; 34) of the eccentric element (12), the eccentric element (12) has a circular shape, wherein the second rotation axis (34) forms the center of the circular shape.

14. The eccentric element (10) according to any one of the preceding claims 1 to 3, wherein: In a bottom view parallel to the first and / or second rotation axis (28; 34) of the eccentric component (12), the weight component (14) has a circular or sector shape, wherein the center (90) of the circular or sector shape is spaced apart from the second rotation axis (34).

15. The eccentric element (10) according to claim 14, wherein: The first axis of rotation (28) extends through a straight line (92) connecting the center (90) of the circle or sector of the weight component (14) with the second axis of rotation (34).

16. The eccentric element (10) according to any one of the preceding claims 1 to 3, wherein: The eccentric component (12) is made of metal, or of a plastic material with a metal insert.

17. The eccentric element (10) according to claim 16, wherein: The metal is steel or aluminum.

18. The eccentric element (10) according to any one of the preceding claims 1 to 3, wherein: The weight component (14) is made of metal.

19. The eccentric element (10) according to claim 18, wherein The metal is steel.

20. The eccentric element (10) according to claim 1, wherein The power tool is an orbital sander or polisher, and / or the working element (30) is a backing plate, a sanding plate or a polishing plate.

21. The eccentric element (10) according to claim 1, wherein During rotation of the eccentric element about the first axis of rotation, the interlocking relationship acts only in a radially outward direction (76) and provides force relief.

22. A power tool in the form of an orbital sander or polisher comprising a tool shaft (16), a motor for driving the tool shaft (16), and an eccentric element (10), to which a working element (30) in the form of a backing plate, sanding plate or polishing plate is releasably connected, Features: The eccentric element comprises the features included in one or more of claims 1-3, 20 or 21 as described above.

Images