Oscillating tool clamping device
Patent Information
- Application Number
- DE102011075228
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2011-05-04
- Publication Date
- 2025-02-06
- Estimated Expiration
- 2031-05-04
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
Prior ArtDE 10 242 737 A1 already discloses a system with a tool holder.Disclosure of the InventionThe invention is based on an oscillating tool clamping device, in particular an oscillating tool clamping device, having a tool holder which has at least a first and a second form-fit element, which are each provided at least for a form-fit connection to a machining tool in a circumferential direction about a machining rotation axis.It is proposed that the form-fit elements are mounted rotatably with respect to one another at least with respect to an axis of rotation which is oriented at least substantially parallel to the machining axis of rotation and / or are mounted movably with respect to one another along at least one axis of movement which is oriented at least substantially perpendicular with respect to an axis which lies parallel to the machining axis of rotation. Preferably, the axis of rotation corresponds at least substantially to the machining axis of rotation. A "tool holder" is to be understood in particular as an arrangement of components which is provided to receive a machining tool in at least one operating state and in particular to fix and preferably clamp it in at least one, advantageously in at least two movement directions and preferably in each movement direction. In particular, the tool holder is formed by components of the oscillation tool clamping device which are in direct contact with the machining tool in an operating state with the machining tool held. A "machining tool" is to be understood in particular as a tool for machining. A "machining rotation axis" is to be understood in particular as an axis of rotation and / or pivot axis of the tool holder at least in an operating state with a securely clamped machining tool. The fact that the machining tool is positively connected to a positive-locking element in the "circumferential direction" about a machining rotation axis is to be understood in particular to mean that the positive-locking element and the machining tool each have at least one positive-locking means, which preferably engage one another and touch one another in particular in an operating state with the machining tool inserted into the tool holder and at least in an operating state with the machining tool clamped in the tool holder. Preferably, a rotation of the respective other part is caused by a rotation of the machining tool or of the form-fitting means inserted into the tool holder through an angle of at least 2°, advantageously of at least 1°, preferably of at least 0.5°. The fact that two axes are "substantially parallel" is to be understood in particular to mean that a straight line which is oriented parallel to the one axis and the other axis intersect at least one point and have an angle of intersection which is in particular less than 10°, advantageously less than 5° and preferably less than 1°. The fact that two axes are "substantially perpendicular" is to be understood in particular to mean that the two axes intersect at least one point and have a cutting angle which deviates from 90° by less than 10°, advantageously by less than 5° and preferably by less than 1°. The fact that two axes "substantially correspond" is to be understood in particular to mean that they are substantially parallel and at their closest point to one another have a distance which is less than 5 mm, advantageously less than 2 mm and preferably less than 0.5 mm. In particular, an efficiency of the oscillation tool can be increased. In particular, a fastening independent of production tolerances of the interlocking means of the machining tool and / or of the interlocking elements can be achieved. In particular, an efficiency can be increased. Play of the machining tool with respect to a rotation about the machining rotation axis in the tool holder can be advantageously prevented, which has the result that torque losses when the machining tool is loaded in the circumferential direction about the machining rotation axis are avoided. Furthermore, by avoiding play, low wear of the form-fitting elements can be achieved.It is furthermore proposed that the oscillation tool clamping device has a limiting unit which is provided to restrict at least one degree of freedom of a rotation and / or a movement of the form-fit elements relative to one another. A "degree of freedom" is to be understood in particular as a movement and / or rotational direction in which a movement is possible. The fact that a rotation and / or movement is "restricted" is to be understood in particular to mean that in particular a rotation, preferably a rotation about the axis of rotation, is enabled in a range of at least 2° and at most 15°, advantageously at most 10° and preferably at most 3°, and / or a movement, preferably a movement in the direction of the machining axis of rotation, is enabled in a range of at least 0.5 mm and at most 3 mm, advantageously at most 2 mm and preferably at most 1 mm. In particular, a loss of at least one of the form-fitting elements can be achieved.According to the invention, it is proposed that the oscillating tool clamping device has a clamping unit which has at least one clamping element which, in at least one operating state, is provided at least for clamping the form-fit elements against one another along the machining rotation axis. A "clamping unit" is to be understood in particular as a unit which secures a machining tool by means of a positive fit and / or by means of a frictional fit along the machining rotation axis. Preferably, the clamping element is part of the tool holder and is provided for clamping the machining tool against the first form-fitting element and the latter in turn against the second form-fitting element in at least the one operating state. The clamping element preferably has at least one clamping head. Preferably, at least one clamping surface is arranged on the clamping head, which is provided for axial overlapping with the machining tool. The expression "axial overlap" is intended here in particular to define an overlap, in particular of partial regions, of at least two components, in particular a straight line running parallel to the machining rotation axis intersects the two components. The clamping surface of the clamping head preferably covers at least a partial region of the machining tool along the machining rotation axis in an operating state in which the machining tool is clamped firmly to the tool holder by means of the clamping head. Particularly preferably, the overlap can be temporarily canceled in an assembled state of the clamping head, in particular for changing the machining tool and / or for changing the position of the machining tool. The oscillation tool clamping device preferably has at least one operating unit which is provided for actuating the clamping unit. The term "operating unit" is intended here in particular to define a unit which has at least one operating element which can be actuated directly by an operator and which is provided for influencing and / or changing a process and / or a state of a unit coupled to the operating unit by actuating and / or by inputting parameters. In particular, a fixing of a position of the form-fitting elements that is free of play with respect to the machining tool can be achieved.It is furthermore proposed that the tool holder has at least one clamping force boosting unit which is provided at least to boost a clamping force transmitted via the clamping element to a greater relative clamping force of the form-fitting elements with respect to one another. Preferably, the relative clamping force serves for a force-fit connection of the form-fit elements, preferably in the circumferential direction and / or for clamping at least one form-fit means of at least one of the form-fit elements to at least one form-fit means of a machining tool. In particular, an improved fixing of the play-free position can be achieved.The clamping force boosting unit preferably has at least one inclined surface which is arranged on at least one of the form-fitting elements. An "inclined surface" is to be understood in particular as a surface which, at least in an operating state with a securely clamped machining tool, is cut from at least one axis parallel to the machining rotation axis at an angle of between 5° and 30°, advantageously between 10° and 20° and preferably between 12° and 18°. This angle is referred to below as "angle of inclination". Preferably, the angle of inclination is at least substantially the same at least 50%, advantageously at least 70%, preferably at least 90%, of the inclined surface. Preferably, both form-fit elements each have at least one inclined surface which together form at least one pair of inclined surfaces which are pressed against one another by the clamping force at least in an operating state with the machining tool firmly clamped. A "pair of inclined surfaces" is to be understood in particular as two inclined surfaces of different form-fitting elements, the inclination angles of which differ from one another by less than 1°. Preferably, two inclined surfaces of a pair of cut surfaces are at least substantially parallel. The fact that two inclined surfaces are substantially parallel is to be understood in particular to mean that at least in an operating state with the machining tool clamped, at least one normal vector of the one inclined surface intersects the other inclined surface at least substantially perpendicularly. In particular, a relative clamping force is established on the inclined surface, which corresponds to the clamping force divided by the sine of the angle of inclination. In particular, a simple, cost-effective clamping force amplification can be achieved.In a further embodiment, it is proposed that the inclined surface is designed as a cone. Preferably, the one form-fitting element, preferably the first form-fitting element, has an inner cone and the other form-fitting element has an outer cone, which engage one another at least in an operating state with the tool holder mounted. Preferably, the at least one clamping cone is provided for a force-fit connection between the form-fit elements. In particular, a simple clamping of the form-fit elements can be achieved.The oscillation tool clamping device preferably has an adjusting unit which is provided at least for fixing a standard relative position of the form-fitting elements. A "standard relative position" is to be understood in particular as a relative position in which the form-fitting elements are in an operating state with the tool holder mounted, which preferably differs from an operating state with the machining tool inserted and / or clamped. In particular, the actuating unit is provided for moving the form-fitting elements back from a relative position deviating from the relative position in the relative position to the relative position in which it is mounted, in an operating state with the tool holder mounted, which differs from an operating state with the machining tool inserted and / or clamped, in particular by an influence of gravity. In particular, operating convenience can be increased.In a further embodiment, it is proposed that the adjusting unit has at least one elastic element which is provided to clamp the form-fit elements against one another if their relative position differs from the standard relative position. In particular, the elastic element is arranged between the form-fit elements in an assembled state of the tool holder. An "elastic element" is to be understood in particular as an element which is formed at least to the extent of 90% from an elastic material, preferably a material having an elastic modulus of between 0.1 N / mm 2 and 100 N / mm 2, preferably between 1 and 10 N / mm 2, in particular from natural and / or chemically produced and / or treated rubber, latex, rubber and / or a comparable material. In particular, a material of the elastic element has a Shore hardness of between 30 and 100, in particular between 45 and 90, advantageously between 60 and 80. In a further embodiment of the invention, the elastic element is formed on at least one of the form-fit elements and / or is connected to at least one of the form-fit elements in a materially integral manner. In an alternative embodiment variant, the elastic element can be designed as a spring element, in particular as a helical spring. A return of the form-fitting elements into the standard relative position independent of the force of gravity can be achieved.Preferably, at least one form-fitting means is arranged on each of the form-fitting elements, which has at least one chamfer. A "chamfer" is to be understood in particular as a surface which has an angle of inclination between 35° and 55° and which preferably has a width of at least 1 mm in its smallest main direction of extension. In particular, the form-fitting means are designed as elevations, preferably as cams, and are provided for engaging into form-fitting means of a machining tool designed as erasers. However, a reverse embodiment is equally conceivable. In particular, simple assembly of the machining tool can be achieved.The invention is furthermore based on a portable power tool, in particular a hand-held power tool with a spindle that can be driven in an oscillating manner, with a power tool clamping device according to the invention. A "portable power tool" is to be understood here in particular as a power tool, in particular a hand-held power tool, which can be transported by an operator without a transport machine. The portable power tool has in particular a mass which is less than 40 kg, preferably less than 10 kg and particularly preferably less than 5 kg. Advantageously, a high level of operating convenience for an operator of the hand-held power tool can be achieved.DRAWINGFurther advantages are evident from the following description of the drawings. The drawing shows an embodiment of the invention. The drawings, specification and claims contain numerous features in combination. The skilled person will expediently also consider the features individually and summarize them to form meaningful further combinations.The following are shown: FIG. 1 shows a machine tool according to the invention with a machine tool clamping device according to the invention in a schematic illustration, FIG. 2 shows an exploded view of a tool holder according to the invention, FIG. 3 shows a top view of the tool holder from FIG. 3 with the machining tool inserted, FIG. 4 shows a schematic illustration of a section through the tool holder from FIG. 2, FIG. 5 is an exploded view of an alternative tool holder according to the invention, and FIG. 6 shows a schematic sectional illustration through a partial region of the tool holder from FIG. 5.DESCRIPTION OF THE EMBODIMENTSFIG. 1 shows a system comprising an electrically operated portable machine tool 38 with an oscillating tool clamping device 10 and a machining tool 16. The machine tool housing 42 comprises two housing half shells 50, 52, which are detachably connected to one another along a plane running through a machining rotation axis 54. The machining rotation axis 54 corresponds to a rotation axis of a spindle 40 of the output unit 48 (FIG. 4 ) designed as a hollow shaft 56. The spindle 40 is provided to drive the machining tool 16 in an assembled state with the machining tool 16 clamped in. The machining tool 16 can be fastened to a tool holder 58 of the output unit 48 for machining workpieces. The tool holder has a first and a second form-fit element 28, 30, which are each provided for a form-fit connection with the machining tool 16 in a circumferential direction 62 about the machining rotation axis 54. The second form-fit element 30 is pressed to the hollow shaft 56. A pivoting movement of the hollow shaft 56 can thus be transmitted to the tool holder 58 (FIG. 4 ).The electric motor unit 44 arranged in the machine tool housing 42 and the transmission unit 46 are provided for generating an oscillating pivoting movement of the spindle 40 and thus of the hollow shaft 56 in an operating mode in a manner known to the person skilled in the art. The oscillating pivoting movement of the hollow shaft 56 is transmitted to the machining tool 16 via the tool holder 58. For the rotationally fixed fastening of the machining tool 16 to the tool holder 58, the machining tool 16 has twelve positive locking means 60 designed as driver recesses, which are designed as holes and are arranged on the machining tool 16 in a circular ring distributed uniformly along a circumferential direction 62. The tool holder 58 has form-fitting means 65, 66, 67 which correspond to the form-fitting means 60 and are designed as hump-like elevations and which, in a mounted state of the machining tool 16 on the tool holder 58, extend through the form-fitting means 60 along straight lines parallel to the machining rotation axis 54. The form-fitting means 65, 66, 67 are uniformly distributed over the two form-fitting elements 28, 30 (FIG. 2 ). In an assembled state of the tool holder 58, the form-fitting means 65, 66, 67 are arranged alternately in a circular ring along the circumferential direction 62 (FIGS. 2, 3 ).For clamping the machining tool 16, the portable machine tool 38 comprises the machine tool clamping device 10 (FIG. 4 ). The machine tool clamping device 10 comprises a clamping unit 12 which has a clamping element 14 which, in a clamping mode, is provided for clamping the machining tool 16 firmly against the tool holder 58 along the machining rotation axis 54 and for bracing the form-fitting elements 28, 30 against one another along the machining rotation axis 54. Furthermore, the clamping unit 12 has clamping heads 20, 21 arranged on the clamping element 14. The clamping element 14 extends along the machining rotation axis 54 to a greater extent than the hollow shaft 56. In this case, the clamping element 14 extends beyond the hollow shaft 56 at an end of the hollow shaft 56 facing the machining tool 16. At an end of the hollow shaft 56 facing away from the machining tool 16, the clamping element 14 likewise extends beyond the hollow shaft 56. The clamping element 14 furthermore extends through holes which are arranged centrally and round in the form-fitting elements 28, 30 and, when a machining tool 16 is inserted into the tool receptacle 58, through a plug-on recess 64 of the machining tool 16. In an assembled state, starting from the clamping head, the hole in the second form-fitting element 30, as viewed from the clamping heads 20, 21, has a diameter which corresponds to a constant diameter of the hole in the first form-fitting element. After a short distance, the hole widens to a larger diameter with a 45° slope and then continues with constant diameter.Furthermore, the clamping unit 12 has an operating unit 88 for actuating the clamping element 14. The operating unit 88 comprises, for actuating the clamping unit 12, an operating lever 90 which is mounted rotatably about an axis of rotation which runs coaxially with the machining axis of rotation 54 of the hollow shaft 56. However, it is also conceivable for the operating lever 90 to be additionally mounted pivotably about a pivot axis running at least substantially perpendicular to the machining rotation axis 54. By means of a mechanism known to the person skilled in the art, the operating unit 88 converts a movement of the operating lever 90 into a translatory movement of the clamping element 14 along the machining rotation axis 54. In a clamping position, in which the operating lever 90 abuts the machine tool housing 42, the operating unit 88 is decoupled from the clamping element 14 and from the hollow shaft 56. The clamping element 14 is designed as a spreading element (cf. FIG. 4 ). A clamping-head-side end of the clamping element 14 is designed in the form of a tuning fork with two long brackets and is continued as a round rod at a contact point of the brackets. At the ends of the two brackets of the clamping element 14, one of the clamping heads 20, 21 is arranged in each case. If the clamping element 14 is moved into a release position by an actuation of the operating unit 88, the brackets are compressed by virtue of the fact that noses arranged on the brackets are guided from a large diameter to a smaller diameter at the slopes of the hole in the second form-fit element 30. The clamping heads 20, 21 are thereby also moved towards the machining rotation axis 54. Axial overlappings of clamping surfaces 72, 74 arranged on the clamping heads 20, 21 with a machining tool 16 inserted in the tool holder 58 are thereby canceled (FIG. 4 ) and the machining tool 16 is released. Conversely, during a clamping process, the noses arranged on the brackets are guided from a small diameter to a larger diameter. In this case, the brackets spread on account of an intrinsic stress which was built up during a release process. The clamping heads 20, 21 produce axial overlaps with a machining tool 16 inserted in the tool holder 58 and finally press the machining tool 16 against the tool holder 58.FIG. 2 shows an exploded view of the tool holder 58; the form-fitting means 65, 66, 67 are uniformly distributed over the two form-fitting elements 28, 30. In an assembled state of the tool holder 58, the form-fitting means 65, 66, 67 are arranged alternately in a circular ring along the circumferential direction 62. Each of the form-fitting elements 28, 30 has six form-fitting means 65, 67 and 66, respectively. The form-fitting means 65, 67 and 66 are each arranged regularly in a circular ring along a circumferential direction 62 on the corresponding form-fitting element 28 and 30. The form-fitting means 65, 66, 67 are formed integrally with the form-fitting elements 28, 30. The form-fitting means 65, 66, 67 are formed integrally with the form-fitting elements 28, 30. The form-fitting means 65, 66, 67 are designed as cams with an oval cross section at an end facing away from the form-fitting element 28, 30, respectively. The form-fitting means 66 of the form-fitting element 30 furthermore have a slightly curved, rectangular block which is arranged between the oval part and the form-fitting element 30. All of the twelve form-fitting means 65, 66, 67 have a chamfer 94. The chamfer 94 is arranged at the oval end of the form-fitting means 65, 66, 67 and has an angle of inclination with respect to the form-fitting means 65, 66, 67 of 45° and a smallest extent of 1 mm.The form-fit elements 28, 30 are mounted rotatably with respect to one another in an assembled state of the tool holder 58 with respect to an axis of rotation which corresponds to the machining axis of rotation 54. The tool holder 58 has a clamping force amplification unit 25 which is provided to amplify a clamping force transmitted via the clamping element 14 relative to a greater relative clamping force of the form-fitting elements 28, 30 with respect to one another. The form-fitting element 28 is pot-shaped and consists of a round base plate and a ring integrally formed on one side of the base plate. An outer diameter of the ring corresponds to a diameter of the bottom plate. The base plate has a circular hole centrally through which the clamping element extends in an assembled state. On a side of the base plate facing away from the ring, the form-fitting means 65, 67 are arranged. Six recesses 36 are arranged in the base plate in a circular ring between the form-fitting means 65, 67, through which recesses the form-fitting means 66 of the form-fitting element 30 extend in an assembled state. The form-fitting element 30 is designed as a base plate with a ring placed on it. An outer diameter of the ring placed on is significantly smaller than a maximum diameter of the base plate of circular design and corresponds to an inner diameter of the hollow shaft 56 with which the positive-locking element 30 is pressed (FIG. 4 ). A maximum diameter of the base plate of the form-fitting element 30 is smaller than a maximum internal diameter of the ring of the form-fitting element 28. The edge of the base plate of the form-fitting element 30 and an inner wall of the ring of the form-fitting element 28 form the clamping force amplification unit 25. The inclined surfaces 68, 70 are formed by the inner wall and the edge and are formed as cones. The inclined surfaces 68, 70 are designed as an inner cone and an outer cone, respectively. A minimum diameter of the rim is somewhat larger than a minimum diameter of the inner wall. The inclined surfaces 68, 70 have the same inclination angles, so that the edge rests flat against the inner wall in a clamping state in which the form-fit elements 28, 30 are clamped against one another. The inclination angle of the inclined surfaces 68, 70 is 15° in a clamping state with respect to a straight line which intersects the inclined surfaces 68, 70 and which is arranged parallel to the machining rotation axis 54. In the clamping state, the clamping force is converted by the inclined surfaces 68, 70 into a plurality of partial relative clamping forces which are each perpendicular to the inclined surfaces 68, 70 and add up to an effective relative clamping force with which the inclined surfaces 68, 70 act on one another. The relative clamping force is, corresponding to the inverse value of the sine of 15°, four times the clamping force. A frictional connection between the positive locking elements 28, 30 caused by the clamping force is thus likewise increased in comparison with a configuration without a clamping force amplification unit 25, in which only two surfaces of the positive locking elements 28, 30, which are each located in a plane on which the machining rotation axis 54 is perpendicular, are braced against one another.The tool holder 58 has a limiting unit 26 which is provided to limit a range of movement of a rotation and a movement of the form-fitting elements 28, 30 with respect to one another. The delimiting unit 26 has two holes 96, 98 arranged diametrically in the form-fitting elements 28, 30 and a bolt 82. The bolt 82 has a length which corresponds to the outer diameter of the form-fitting element 28. In an assembled state, the holes 96, 98 overlap and the bolt 82 extends through the four holes 96, 98. The holes 96 have a diameter that is 1 mm larger than the diameter of the bolt 82. Thus, the first form-fitting element 28 can be moved around the form-fitting element 30 in a small angular range until a boundary of the holes 96 abuts the bolt 82. Likewise, in an assembled state, a movement of the form-fitting element 28 against the form-fitting element 30 along the machining rotation axis 54 is limited to a distance of 1 mm.Furthermore, the tool holder 58 has an adjusting unit 27 which is provided for fixing a standard relative position of the form-fitting elements 28, 30. The adjusting unit 27 has an elastic element 32, which is provided to clamp the form-fit elements 28, 30 against one another if their relative position differs from the standard relative position. The adjusting unit 27 is arranged between the positive locking elements 28, 30 in an assembled state. The elastic element 32 is made of a soft rubber and is substantially formed as an annular disk. The elastic member 32 is formed of a single material. The material of which the elastic member 32 is formed has a Shore hardness of 70. A maximum outer diameter of the elastic element 32 corresponds to the minimum outer diameter of the base plate of the form-fit element 30. The elastic element 32 has six formations 34 which are designed as pockets with a hole 24 and are provided to receive the positive locking means 66 of the positive locking element 30. In an assembled state, the formations 34 each surround one of the slightly curved cuboid-like blocks of the form-fitting means 66 and the oval ends 66 of the form-fitting means extend through the holes 24. The formations 34 are in turn accommodated by the recesses 36 of the form-fitting element 28. In the circumferential direction 62, a formation 34 of the elastic element 32 is arranged at each point between the form-fit elements 28, 30. In an assembled state, one side in each case lies in the circumferential direction 62 in the clamping mode, or both sides of the formations 34 lie against both form-fit elements 28, 30 in a released mode.In principle, the elastic element 32 can be connected, in particular glued or welded, to the form-fit element 28 and / or to the form-fit element 30 in a materially integral manner.In FIG. 3, the tool holder 58 with the machining tool 16 inserted is in a view in which the tool holder 58 is arranged behind the machining tool 16. In the relative position of the standard, which is assumed in an operating state in an assembled state of the tool holder 58 that differs from an operating state with the machining tool 16 inserted, the form-fit elements 28, 30 are positioned by the configuration of the formations 34, the recesses 36 and the form-fit means 66 in such a way that in an assembled state an angle 86 between a form-fit means 67 of the form-fit element 28 and an adjacent form-fit means 66 of the form-fit element 30 is 1° greater than an angle 84 between the form-fit means 66 and a form-fit means 65 of the form-fit element 28. If a machining tool 16 is inserted into the tool holder 58, the form-fitting means 60 first engage around tips of the form-fitting means 65, 66, 67. the form-fitting means 60 are likewise of oval design and, in order to take account of production inaccuracies, are of minimally larger design than the oval ends of the form-fitting means 65, 66, 67. The form-fitting means 60 are arranged uniformly in the machining tool 16 at angular distances of 30°. The form-fitting element 28 is rotated relative to the form-fitting element 30 when the machining tool 16 is pushed further onto the tool holder 58 until the angles 84, 86 differ from one another only to such an extent, for example by 0.2°, that the machining tool 16 can be pushed completely onto the tool holder 58. In this case, the elastic element 32 builds up a slight tension between the form-fit elements 28, 30. The form-fitting means 60 encompass the oval form-fitting means 65, 66, 67 in this case. The elastic element 32 ensures that a play, which arises on account of the greater configuration of the form-fitting means 60 in relation to the form-fitting means 65, 66, 67, is eliminated between the machining tool 16 and the tool holder 58, or between the form-fitting means 60 and the form-fitting means 65, 66, 67. A relative position that occurs when the machining tool 16 is placed on differs from the standard relative position. The set relative position is fixed by a clamping operation of the clamping unit 12. A maximum torque which can be exerted on the machining tool 16 without causing a relative movement of the machining tool 16 within the clearance with respect to the tool holder 58 is thus determined, instead of by a frictional connection of the machining tool 16 with respect to the tool holder 58 or with respect to the clamping element 14, by a frictional connection between the positive-locking elements 28, 30, which is at least three times as large due to the clamping force amplification unit 25. After releasing the clamping unit, the machining tool 16 can be removed from the tool holder 58. The form-fit elements 28, 30 return into their standard relative position due to the tension of the elastic element 32.In a further embodiment, the chamfers 94 can be dispensed with, wherein the form-fitting means 65, 67 project further from the tool holder 58 than the form-fitting means 66 in an assembled state. Thus, in a first step, the machining tool 16 is pushed onto the form-fitting means 65, 67, in a second step, the machining tool 16 together with the form-fitting element 28 is rotated manually in order to align positions of the form-fitting means 60 with positions of the form-fitting means 66 and, in a third step, the machining tool 16 is pushed onto the form-fitting means 66. In a further embodiment without elastic element 32, the play can be compensated for by manual rotation of the form-fit elements 28, 30 with respect to one another in an operating state in which the machining tool 16 is pushed onto the tool holder 58. During a clamping via the clamping unit 12, this relative position must be held in place manually until the clamping is completed.FIG. 4 shows a section through the tool holder 58 and a part of the clamping unit 12 along a plane which runs through the machining rotation axis 54. The spindle 40, which is designed as a hollow shaft 56, comprises the ring of the positive-locking element 30 and is firmly connected to the latter. Furthermore, the clamping element 14, which is designed as an expanding element, and a spring unit 76, which has a compression spring 78, which is designed as a helical spring, are arranged in the hollow shaft 56. The spring unit 76 clamps the form-fit element 30 against the clamping element 14. The clamping element 14 is mounted at a point at which the brackets of the clamping element 14 converge on a bolt 80 which is fixedly connected to the hollow shaft 56. During assembly, the elastic element 32 and the form-fitting element 28 are brought together with the form-fitting element 30, such that the holes 96, 98 overlap. The bolt 82 is guided through the overlapping holes 96, 98 and between the brackets of the clamping element 14 and is firmly connected to the form-fit element 30, in this case pressed (cf. also FIG. 2 ). The mounting recess 64 of the machining tool 16, which is arranged centrally and round between the form-fitting means 60, forms a channel with holes arranged in the form-fitting elements 28, 30 and in the elastic element 32, through which channel the clamping element 14 is guided. The holes in the form-fitting element 28 and the elastic element 32 have the same diameter as the plug-on recess 64. In a state with the machining tool 16 clamped in place, the clamping surfaces 72, 74 of the clamping heads 20, 21 axially cover respective regions of the machining tool 16 close to the plug-on recess 64.Furthermore, embodiments are conceivable in which the spring unit 76 is formed by other spring types, for example a stack of disk springs. Furthermore, alternative embodiments of the clamping unit 12 and in particular of the clamping element 14 are known, which are compatible with the presented embodiment of the tool holder 58.In further embodiments, it is conceivable that the form-fitting elements 28, 30 are formed in the manner of slides, wherein one of the form-fitting elements 28, 30 has straight guide means which serve for guiding the other form-fitting element 28, 30 and that they are mounted such that they can move relative to one another along a movement axis which is oriented perpendicularly with respect to an axis which lies parallel to the machining rotation axis.Furthermore, embodiments are conceivable in which cams are arranged on the machining tool 16, which engage in form-fitting means of the form-fitting elements 28, 30 configured as driver recesses, and / or in which the form-fitting means 60 on the machining tool 16 and / or the form-fitting means 65, 66, 67 on the form-fitting elements 28, 30 are arranged irregularly, in particular in order to prescribe an installation position of the machining tool 16.In FIGS. 5 a, 5 band 6, a further exemplary embodiment of the invention is shown. The following descriptions are limited substantially to the differences between the exemplary embodiments, wherein with regard to identically denoted components, in particular with regard to components with the same reference numerals, reference can also be made in principle to the drawings and / or the description of the exemplary embodiment of FIGS. 1 to 4. To distinguish between the exemplary embodiments, the letter a is appended to the reference numerals of the further exemplary embodiment.FIGS. 5 aand 5 b show an alternative embodiment of the tool holder 58 The tool holder 58 afurther comprises two form-fitting elements 28 a, 30 awith in each case six form-fitting means 65 a, 67 aand 66 a, an elastic element 32 aand a bolt 82 a. The components are each shown in an exploded view from obliquely below (FIG. 5 a ) and from obliquely above (FIG. 5 b ). An edge of a base plate of the positive-locking element 30 aand an inner wall of a ring of the positive-locking element 28 aare formed parallel to a machining rotation axis 54 ain an assembled state. The slightly curved, rectangular blocks of the form-fitting means 66 are replaced by slightly curved prism-like blocks of the form-fitting means 66 a. The shaped portions 34 aof the elastic element 32 a, which shaped portions are formed as pockets, and the recesses 36 ain the form-fitting element 28 aare correspondingly adapted in terms of their shape. Instead of the inclined surfaces 68, 70 of the form-fitting elements 28, 30 which are designed as cones, the form-fitting elements 28 a, 30 aeach have a toothed structure arranged in a ring between the form-fitting means 66 a(see a side) or the recesses 36 a(see b side) and a hole in the center of the form-fitting elements 28 a, 30 a. The toothed structures are provided to engage each other in an assembled state. For this purpose, the elastic element 32 ais designed as a narrow ring. The toothed structures each have a plurality of side-by-side arranged valleys, wherein the valleys of the form-fitting element 30 aare each formed by two inclined surfaces 68 aand a cover surface and the valleys of the form-fitting element 28 aare each formed by two inclined surfaces 70 aand a cover surface, wherein the cover surface is arranged in a plane which, in an assembled state, lies perpendicular to the machining rotation axis 54 a. The inclined surfaces 68 a, 70 aeach have an angle with respect to the cover surface which is 75°.FIG. 6 shows a section through the toothed structures in an assembled state. The valleys of the toothed structure of one of the form-fitting elements 28 a, 30 aengage in each case between valleys of the other form-fitting element 28 a, 30 a. In a standard relative position, inclined surfaces 68 a, 70 aare situated against one another in pairs, and a center 100 a, 104 aof a wall lies 0.5 mm next to a center 102 a, 106 aof a valley between the opposite walls. In this stationary relative position, the form-fitting means 65 a, 66 a, 67 aof the form-fitting elements 28 a, 30 aare arranged uniformly at angular distances of 30°. During a clamping process with the machining tool inserted, the form-fit elements 28 a, 30 aare moved towards one another along the machining rotation axis 54 abecause of a clamping force of a clamping element. Due to the inclined surfaces 68 a, 70 alocated against one another, this movement is converted into a rotation of the positive locking element 28 aabout the machining rotation axis 54 a. In this case, the elastic element 32 aconstructs a slight tension between the form-fit elements 28 a, 30 a. If any play is compensated, the clamping force ensures that this state is fixed. When the clamping force is released, the tension of the elastic element 32 aprovides a rotation of the form-fit element 28 a, which restores the play and releases the machining tool 16 a.
Claims
Oscillating tool clamping device (10), having a tool holder (58; 58a) which has at least one first and one second form-fitting element (28, 30; 28a, 30a), which are each provided at least for a form-fitting connection to a machining tool (16) in a circumferential direction (62) about a machining rotation axis (54; 54a), wherein the form-fitting elements (28, 30; 28a, 30a) are mounted rotatably with respect to one another with respect to an axis of rotation which is oriented parallel to the machining rotation axis (54; 54a) and / or along at least one movement axis which is oriented perpendicularly with respect to an axis which is parallel to the machining rotation axis (54; 54a), which are mounted such that they can be moved relative to one another, wherein the machining rotation axis (54, 54a) corresponds to a rotation axis of a spindle (40), which is designed as a hollow shaft (56), of an output unit (48), characterized bya clamping unit (12), which has at least one clamping element (14), which in at least one operating state is provided for clamping the positive locking elements (28, 30; 28a, 30a) relative to one another along the machining rotation axis (54; 54a), wherein along the machining rotation axis (54; 54a) the clamping element (14) has a greater extent than the hollow shaft (56), wherein the clamping element (14) in a mounted state extends through the hollow shaft (56), wherein the clamping element (14) extends beyond the hollow shaft (56) at an end of the hollow shaft (56) facing the machining tool (16).Oscillation tool clamping device (10) according to Claim 1, characterized bya limiting unit (26; 26a) which is provided to restrict at least one movement margin of a rotation and / or a movement of the form-fitting elements (28, 30; 28a, 30a) with respect to one another.Oscillating tool clamping device (10) according to Claim 1, characterized in that the tool holder (58; 58a) has at least one clamping force amplification unit (25; 25a), which is provided at least to amplify a clamping force transmitted via the clamping element (14) with respect to one another to form a greater relative clamping force of the form-fitting elements (28, 30; 28a, 30a).Oscillation tool clamping device (10) according to Claim 3, characterized in that the clamping force amplification unit (25; 25a) has at least one inclined surface (68, 70; 68a, 70a) which is arranged on at least one of the form-fitting elements (28, 30; 28a, 30a).Oscillation tool clamping device (10) according to Claim 4, characterized in that the inclined surface (68, 70; 68a, 70a) is designed as a cone.Oscillating tool clamping device (10) according to one of the preceding claims, characterized byan adjusting unit (27; 27a) which is provided at least for fixing a standard relative position of the form-fitting elements (28, 30; 28a, 30a).The oscillating tool clamping device (10) according to claim 6, characterized in that the adjusting unit (27; 27a) comprises at least one elastic element (32; 32a), which is provided to clamp the form-fit elements (28, 30; 28a, 30a) against each other if their relative position differs from the standard relative position.Oscillating tool clamping device (10) according to one of the preceding claims, characterized in that at least one form-fitting means (65, 66, 67; 65a, 66a, 67a) is arranged in each case on the form-fitting elements (28, 30; 28a, 30a), which has at least one chamfer (94; 94a).Portable power tool, in particular portable power tool having a spindle (40) which can be driven in an oscillating manner, having at least one oscillating tool clamping device (10) according to one of the preceding claims.A system comprising at least one portable machine tool (38) according to claim 9 and at least one machining tool (16) provided for clamping in the oscillating tool clamping device (10) of the portable machine tool (38).
Citation Information
Patent Citations
system with a tool holder
DE10242737A1