EP1302286B1 - Machine tool with securing flange - Google Patents

Description

The invention relates to a machine tool having a drive shaft for driving a tool, with a recess at a free end of the drive shaft, with a removable mounting flange having on a side facing the drive shaft a mounting portion which is positively inserted into the recess of the drive shaft, and on the opposite side has a flange portion, wherein the tool has a mounting recess.

The invention further relates to a mounting flange for the positive fastening of a tool with a mounting opening on a recess at a free end of a drive shaft of a machine tool.

Such a machine tool and mounting flange are known from US-A-6,093,090.

In the known machine tool is a grinding machine, in which the direction of rotation of the grinding wheel is reversible. In order to prevent loosening of the grinding wheel when the direction of rotation is reversed, the drive shaft of the grinding machine is hollow. The drive shaft has an external thread and an internal thread within the cavity, which extends in opposite directions to the external thread. To connect the tool to the drive shaft, a hollow sleeve is provided which has at a first end an internal thread which can be screwed onto the external thread of the drive shaft. The tool has a circular center hole and can be secured by a retaining bush which positively engages the hexagonal retainer by means of a screw which is screwed through the hole of the tool, the sleeve and the tool holder in the opening of the drive shaft.

In this way, although by the opposing thread between the drive shaft, hollow sleeve and the internal thread of the drive shaft a backup against loosening of the tool when reversing the direction of rotation allows, however, the attachment is complicated and complicated.

Further attention should be drawn to EP-A-1 213 107 A1, which is prioritized earlier than the present application, but not prepublished.

From this, a receptacle for mounting a tool on a drive shaft is known, with a mounting opening which is formed on the tool or on the drive shaft and cooperates with a correspondingly shaped, raised mounting portion on the other of the two elements to form a positive connection for transmitting a Torque to form between the drive shaft and the tool, wherein the attachment opening is rotationally symmetrical to a central axis extending through the attachment opening, and wherein the attachment opening has at least three outwardly facing, rounded tips, and wherein each two adjacent tips by a leading to the central axis Curvature distance are connected.

Another machine tool known from EP-A-0 369 390 has an oscillation drive by means of which a tool mounted on the free end of the drive shaft oscillates at high frequencies in the range of about 5,000 to 25,000 oscillations per minute and small pivoting angle in the range between 0.5 ° and 5 ° is added. The tool can be used by its oscillation about the longitudinal axis of the drive shaft for special cutting tasks, for example, to cut through the adhesive beads of windshields when they need to be replaced. In addition, there are numerous other uses in the field of cutting, sawing, grinding, polishing or the like.

From EP 0 369 390 A2 it is known to provide the tool with a mounting opening with which it can be placed positively on a mounting portion of the drive shaft and then by means of a nut which can be screwed onto the end of the drive shaft to fix.

In addition, designs have become known through use in which a threaded blind hole is provided at the free end of the drive shaft into which a fastening screw can be screwed, which rests with a head of sufficient diameter on the workpiece surface to fix it to the drive shaft.

To ensure a safe power transmission, and at the same time to allow a precise alignment of the tool with respect to a job, a positive engagement between the mounting hole of the tool and the mounting portion of the drive shaft is desired.

A disadvantage has been found here that a final fixation of the angular position of the tool with respect to the drive shaft can only be reached when the relevant fastening nut or, the fastening screw is sufficiently tightened on the thread of the drive shaft. Only in the last area, just before tightening the nut or screw, the tool is secured against further rotation.

The invention is therefore an object of the invention to provide an improved machine tool that allows a positive locking and securing a tool to be fastened against rotation already at an earlier date, possibly already in the positioning on the free end of the drive shaft of the machine tool.

This object is achieved with a machine tool according to the aforementioned type in that the mounting recess of the tool is adapted to the shape of the mounting portion of the removable mounting flange such that the tool is held with its mounting recess form-fitting manner to the mounting portion, if this from the outside through the fastening recess engages in the recess of the drive shaft.

The object of the invention is completely solved in this way.

Instead of a raised mounting portion at the free end of the drive shaft, a recess is now provided at the free end of the drive shaft. The tool is connected with the aid of a mounting flange, which engages positively with a mounting portion in the mounting recess of the tool and which is also positively inserted into the recess at the free end of the drive shaft, positively connected to the drive shaft. In this case, it is not necessary to first tighten a screw or a nut until finally a final form-locking fixation, d. H. Also, a backup against an angular rotation, is achieved. Rather, the tool can be placed together with the mounting flange on the drive shaft and immediately held by the mounting flange form-fitting manner to the drive shaft, while then a fixing, z. As a screw is used to fix the tool in this position finally to the drive shaft.

For this purpose, according to an advantageous embodiment of the invention, a threaded blind hole is provided on the drive shaft, into which a fastening screw can be screwed. The mounting flange is penetrated in this embodiment of an opening for receiving the mounting screw.

Thus, the tool can initially be attached together with the mounting flange on the drive shaft and fixed in a form-fitting manner, while then the fastening screw inserted through the opening of the mounting flange and screwed into the threaded blind hole to secure the tool to the drive shaft.

According to a further embodiment of the invention, the attachment portion of the mounting flange is formed continuously with a uniform cross-section both for positive reception in the recess of the drive shaft, as well as for positive reception in the mounting hole.

Such a design is useful when the shape of the mounting hole of the tool and the recess coincides at the free end of the drive shaft. In this case, the fastening section formed with a uniform cross section of the mounting flange can form a positive engagement both with the mounting opening of the tool, as well as with the recess at the free end of the drive shaft.

According to an alternative embodiment of the invention, the attachment portion has a first region, which is designed for positive reception in the recess of the drive shaft, and a second region, which is designed for positive reception in the attachment opening, wherein the first and the second region deviate from one another are formed.

Such a design is useful if the shape of the attachment opening of the tool is deviating and not compatible with the recess at the free end of the drive shaft. In this case, the two portions of the mounting portion of the mounting flange may be adapted to be adapted to both the mounting hole of the tool, as well as with the recess at the free end of the drive shaft to form a positive engagement.

In this case, the mounting flange serves as an adapter between the different shapes of the mounting opening of the tool on the one hand and the recess at the free end of the drive shaft on the other.

The mounting flange has in an advantageous development of the invention on the side facing away from the machine tool an extension for at least partially recessed receiving a screw head.

In this way, a fastening screw, which is used for fixing the mounting flange and tool on the drive shaft, sunk or at least partially sunk on the mounting flange are added, which allows an advantageous work.

The recess at the free end of the drive shaft may, for example, the shape of a regular polygon, preferably in the form of a hexagon.

In this case, a continuous mounting portion can be used on the mounting flange with a suitably formed polygonal shape to positively connect both the mounting opening of the tool and the recess at the free end of the drive shaft with each other. The tool can in this case, as known in the art, for. Example, have a mounting opening in the form of a Zwölfkants according to EP 0 369 390 A2, in which between adjacent outer corners one each more inwardly offset inside corner is formed, so that overall results in a star shape. Such a mounting opening can be defined with a continuous fastening portion in the form of a hexagon, the cross section of which is adapted accordingly, positively against the recess at the free end of the drive shaft by means of the mounting flange.

According to an advantageous embodiment of the invention, the corner regions of the polygonal recess at the free end of the drive shaft are widened by round sections to the outside in this embodiment.

In this way, a clamping of the mounting portion of the mounting flange is avoided in the recess of the drive shaft. It also facilitates the manufacturability.

It is understood that the recess on the drive shaft, the mounting portion of the mounting flange and the mounting hole on the tool can also be arbitrarily shaped differently, provided that the respective shapes are matched accordingly.

For example, it is conceivable to provide a plurality of recesses at predetermined locations for receiving projections of the fastening flange at the free end of the drive shaft.

According to a further variant of the invention, the recess has a plurality of preferably six rounded tips which are arranged at regular angular distances from each other radially spaced from the longitudinal axis of the drive shaft with each pair of adjacent peaks being connected by curvature portions that advance from the adjacent peaks toward the longitudinal axis and converge at a common vertex.

Such a shape has special advantages for the purpose of a uniform torque transmission even at high loads. Since no sharp-edged tips are provided and the power transmission takes place essentially over the curved sections between the rounded tips, punctiform loads and high surface pressures are avoided, whereby a deflection of the positive connection is reliably avoided even after a long period of use.

If desired, of course, this shape can be combined with other forms, if, for example, the tool has a different shaped mounting opening. Conversely, a tool with such a shaped mounting opening on a different shaped recess at the free end of the drive shaft by means of the mounting flange are positively fixed, provided that this has two suitably adapted areas at its attachment portion.

The object is further achieved by a mounting flange for positive fastening of a tool having a mounting opening on a recess at a free end of a drive shaft of a machine tool, wherein a fixing portion is provided, whose outer contour is adapted to the inner contour of the mounting hole of the tool and the recess of the drive shaft to allow a positive connection between the tool, mounting flange and the recess, and wherein a protruding from the mounting portion outwardly flange portion is provided, which allows an abutment on a surface of the tool in the region of the mounting hole.

It is understood that the features of the invention mentioned above and those yet to be explained can be used not only in the respectively specified combination but also in other combinations or alone, without leaving the scope of the invention.

Fig. 1

eine Explosionsdarstellung einer erfindungsgemäßen Antriebswelle mit darüber im Abstand angeordnetem Werkzeug, auf dessen Befestigungsöffnung ein Befestigungsflansch aufgesetzt ist, bevor die so gebildete Einheit in einer Ausnehmung am freien Ende der Antriebswelle eingesetzt werden kann;

Fig. 2

eine Ansicht des Werkzeuges gemäß Fig. 1 von oben;

Fig. 3

eine Ansicht des Befestigungsflansches gemäß Fig. 1 von der Antriebswelle aus gesehen;

Fig. 4

eine Seitenansicht des Befestigungsflansches gemäß Fig. 3;

Fig. 5

einen Querschnitt des Befestigungsflansches gemäß Fig. 3;

Fig. 6

eine Zusammenstellung von Befestigungsschraube, Befestigungsflansch, Werkzeug und Antriebswelle in einer Montageposition voneinander beabstandet;

Fig. 7

eine Ansicht der Antriebswelle von außen;

Fig. 8

eine abgewandelte Ausführung eines Befestigungsflansches von der Antriebswelle aus gesehen;

Fig. 9

eine weitere Abwandlung des Befestigungsflansches, von der Antriebswelle aus gesehen;

Fig. 10

eine Abwandlung der Antriebswelle, in der Ansicht von außen.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings. Show it:

Fig. 1

an exploded view of a drive shaft according to the invention with tool spaced above it, on the mounting opening a mounting flange is placed before the unit thus formed can be used in a recess at the free end of the drive shaft;

Fig. 2

a view of the tool of Figure 1 from above.

Fig. 3

a view of the mounting flange of Figure 1 seen from the drive shaft.

Fig. 4

a side view of the mounting flange of FIG. 3;

Fig. 5

a cross section of the mounting flange of FIG. 3;

Fig. 6

an assembly of fastening screw, mounting flange, tool and drive shaft in a mounting position spaced from each other;

Fig. 7

a view of the drive shaft from the outside;

Fig. 8

a modified embodiment of a mounting flange seen from the drive shaft;

Fig. 9

a further modification of the mounting flange, seen from the drive shaft;

Fig. 10

a modification of the drive shaft, in the view from the outside.

In Fig. 1, a machine tool is merely indicated purely schematically with a dash-dotted line and generally designated by the numeral 10. The machine tool 10 comprises a housing 12 in which an electric motor is accommodated, which via a suitable transmission, a drive shaft 16 about its longitudinal axis 17 at high frequency in the range of about 5,000 to 25,000 oscillations per minute and with a small pivot angle in the range of about 0, 5 to 5 ° oscillates back and forth. The overall drive formed by the electric motor and the associated oscillation gear, which is not shown in detail in Fig. 1, is indicated purely schematically by the numeral 14. The drive shaft 16 protrudes with a free end of the housing 12, wherein the free end is formed as a receiving flange 18. In the receiving flange 18, a mounting opening 20 with a hexagonal shape, which will be explained in more detail below, recessed. On the drive shaft 16, a threaded blind hole 22 is further provided, which is designed to receive a fastening screw. In Fig. 1, spaced from the drive shaft 16, a tool 24 is shown, which in the case shown is a cutting blade, which can be used in conjunction with the oscillating drive 14 of the machine tool 10, as to the Klebewülste of slices , such as B. to cut through windshields of motor vehicles. The tool 24 has, according to FIG. 2, at one end a twelve-shaped fastening opening 26, in which in each case an inwardly offset inner corner is formed between adjacent outer corners, so that overall a star-shaped fastening opening 26 results. At the opposite end of the attachment opening 26, the tool 24 has a right angle projecting Cutting part 28 which is sharpened at both side edges and terminates in a common tip.

For attachment of this tool 24 to the drive shaft 16, a mounting flange 30 is provided which extends through the mounting opening 26 with a correspondingly shaped mounting portion and which is positively inserted into the recess 20 of the drive shaft. The mounting flange 30 can thus be inserted through the attachment opening 26 with its attachment portion and engage in the recess 20 of the drive shaft 16, so that a total of the tool 24 is positively connected via the mounting flange 30 with the drive shaft 16, as will be explained in more detail below.

The shape of the mounting flange 30 can be seen in more detail from Figures 3 to 5. The mounting flange 30 has on a drive shaft 16 side facing a mounting portion 34 which is formed hexagon-shaped and is of course tuned in shape and dimension to the recess 20 at the end of the drive shaft 16. The attachment portion 34 terminates in a flange portion 32 which projects outwardly from the attachment portion 34 and thus forms a stop surface for resting on the tool 24. The mounting flange 30 is penetrated by a central opening 36 which is provided on its side facing away from the drive shaft 16 with an extension 38, so that a screw can be inserted with its shaft through the opening 36 and sunk with her head in the extension 38 ,

The shape of the hexagonal recess 20 in the receiving flange 18 of the drive shaft 16 can be seen in Fig. 7 in more detail. The recess 20 is formed hexagonal, but has round corner regions 44, the shape of Fig. 7 can be seen in more detail. This rounded widening of the corners to the outside prevents it that the mounting flange 34 is stuck with its mounting portion 34 after prolonged use in the recess 20 so that it can only be removed with a tool. In addition, this form is easier to produce.

In Fig. 6 the attachment of the tool 24 by means of the mounting flange 30 and the fastening screw 40 is shown schematically.

First, the mounting flange 30 is inserted with its attachment portion 34 through the mounting hole 26, so that the mounting flange 30 comes with its flange portion 32 on the surface of the tool 24 for conditioning. The unit thus formed is inserted with the protruding from the tool 24 part of the mounting portion 34 in the recess 20 on the receiving flange 18 of the drive shaft 16. If necessary, in this case the angular position of the tool 24 with respect to the drive shaft 16 can be corrected. Subsequently, the fastening screw 40 is inserted through the opening 36 of the mounting flange 30 and screwed into the threaded blind hole 22 until the tool 24 is securely fixed to the mounting flange 30. To operate the screw an unillustrated Allen is provided in the head 42 of the screw.

Some variants of the shape of the attachment portion or the shape of the recess on the receiving flange of the drive shaft are explained below with reference to Figures 8, 9 and 10.

Corresponding reference numerals are used for corresponding parts.

Fig. 8 shows a modified mounting flange 30a in the view seen from the drive shaft 16 from. The only difference from the previously described with reference to FIG. 3 mounting flange 30 is in a modified form of the mounting portion 34 a. The attachment portion 34a has six rounded tips 46 at regular angular intervals of 60 ° with respect to each other, wherein a pair of adjacent tips 46 are interconnected by curvature portions or flanks 48 leading to the center of the opening 36 and each in a common Vertex 50 merge into each other. In this way, a regular polygon with six rounded tips is formed, which are connected to each other via inwardly leading curvature portions 48.

Such a shape is advantageous for a uniform torque transmission and prevents deflection of the positive connection, since no sharp-edged corner regions and the like. Are present.

In the case shown, both the recess 20 of the drive shaft 16 and the mounting opening 26 is adapted in a corresponding manner to the shape of the mounting portion 34 a, so that, as described above with reference to FIG. 6, the Tool with the aid of the mounting flange 30a and the fastening screw can be positively secured to the receiving flange 18 of the drive shaft 16.

A modified embodiment of the mounting flange is shown in Fig. 9 and indicated generally by the numeral 30b. The view from the drive shaft shows that the attachment portion 34b of the attachment flange 30b has two regions, namely a first region 54 which has a hexagonal outline, followed by a second region 52 in the direction of the drive shaft 16, whose cross section the cross section of the attachment portion 34a of FIG. 8 corresponds.

This now makes it possible to attach a tool 24 with a star-shaped attachment opening 26 according to FIG. 2 with the aid of the attachment flange 30b to a drive shaft whose recess 20 has a shape corresponding to the polygonal shape according to FIG.

In this case, the mounting flange 30b serves as an adapter for the different shapes of the mounting hole 26 and the recess on the receiving flange of the drive shaft.

Another variant is shown in FIG. Fig. 10 shows only the view of a modified drive shaft 16c from the outside. It is understood that the shape of the attachment portion of the associated mounting flange is adapted accordingly. The recess 20c, which is provided in the receiving flange 18 of the drive shaft 16c, consists in the illustrated Case of two cylindrical recesses 56, 58, which are opposite to each other, offset by 180 ° to each other at the same distance from the threaded blind hole 22 in the receiving flange 18 are arranged.

It is understood that these examples represent only a small selection of the possible variants of the shapes of the recess 20 at the free end of the drive shaft 16 and the associated mounting flange 30 and the shapes of the mounting opening of the tool 24 and that any further modifications within the scope of the following claims possible are.

Claims (17)

1. Machine tool comprising a drive shaft (16) for driving a tool (24), a recess (20, 20c) at a free end (18) of the drive shaft (16), a detachable securement flange (30, 30a, 30b) having a securement section (34, 34a, 34b) on a side facing the drive shaft (16), the securement section being form-fitted for insertion into the recess (20, 20c) of the drive shaft (16) and comprising a flange section (32) on the opposite side, wherein the tool (24) comprises a securement opening (26), characterized in that the securement opening (26) is adapted to the shape of the securement section (34, 34a, 34b) of the securement flange (30, 30a, 30b) such that the tool is secured with its securement opening form-fitted to the securement section, when the latter protrudes from the outside through the securement opening (26) into the recess (20, 20c) of the drive shaft (16).
2. Machine tool according to claim 1, characterized in that the drive shaft (16) comprises a threaded hole (22) for receiving a securement screw (40), and wherein the securement flange (30, 30a, 30b) is penetrated by an opening (36) for receiving the securement screw.
3. Machine tool according to claim 1 or 2, characterized in that the securement section (34, 34a) comprises a uniform cross section for form-fit support in the recess (20, 20c) of the drive shaft (16) as well as for form-fit support in the securement opening (26).
4. Machine tool according to claim 1 or 2, characterized in that the securement section (34b) comprises a first region (54) being adapted for form-fit support in the recess of the drive shaft (16), and further comprises a second region (52) adapted for form-fit support in the securement opening (26), wherein the first (54) and second (52) regions are of different configuration.
5. Machine tool according to any of the preceding claims, characterized in that the opening (36) of the securement flange (34, 34a, 34b), at the side facing away from the machine tool (10), comprises an enlargement (38) for receiving a screw head (42) at least partially recessed.
6. Machine tool according to any of the preceding claims, characterized in that the recess (20) at the free end of the drive shaft (16) is formed as a regular polygon, preferably as a hexagon.
7. Machine tool according to claim 6, characterized in that the corner regions are extended by round sections (44).
8. Machine tool according to any of claims 1 to 5, characterized in that the recess comprises a plurality of preferably six rounded tips (46), which are located radially distant from the longitudinal axis (17) of the drive shaft (16) at regular angular intervals to each other, wherein each pair of adjacent tips (46) is connected by curved sections (48) which protrude from the adjacent tips (46) into the direction of the logitudinal axis (17) and coincide in a common summit (50).
9. Machine tool according to any of claims 1 to 5, characterized in that the recess (20, 20c) comprises a plurality of recesses (56, 58) at predetermined locations for receiving protrusions of the securement flange.
10. Securement flange for form-fit securement of a tool (24) by means of a securement opening (26) to a recess (20, 20c) located at a free end of a drive shaft (16) of a machine tool (10), in particular according to claim 1, comprising a securement section (34, 34a, 34b), the outer contour of which is adapted to the inner contour of the securement opening (26) of the tool (24) and to the recess (20, 20c) of the drive shaft (16), so as to allow a form-fit between the tool (24), the securement flange (30, 30a, 30b) and the recess (20, 20c), and further comprising a flange section (32) protruding from the securement section (34, 34a, 34b) to the outside and allowing a resting against a surface of the tool (24) in the region of the securement opening (26).
11. Securement flange according to claim 10, characterized in that is penetrated by an opening (36) for receiving a securement screw (40).
12. Securement flange according to claim 10 or 11, characterized in that the securement section (34b) comprises a first region (54) being adapted for form-fit support in the recess (20, 20c) of the drive shaft (16), and further comprises a second region (52) adapted for form-fit support in the securement opening (26), wherein the first (54) and second (52) regions are of different configurations.
13. Securement flange according to claim 10 or 11, characterized in that the securement section (34, 34a) comprises a first region being adapted for form-fit support in the recess (2b) of the drive shaft (24), and further comprises a second region adapted for form-fit support in the securement opening (26), wherein the first and second regions are of identical cross sections.
14. Securement flange according to any of claims 10 to 13, characterized in that the opening (36), at the side facing away from the machine tool (10), comprises an enlargement (38) for receiving a screw head (42) at least partially recessed.
15. Securement flange according to any of claims 12 to 14, characterized in that at least one of the two regions of the securement section (34, 34a, 34b) is formed as a regular polygon, preferably as a hexagon.
16. Securement flange according to any of claims 12 to 15, characterized in that at least one of the two regions of the securement section comprises a plurality of preferably six rounded tips (46), which are located radially distant from the longitudinal axis (17) of the drive shaft (16) at regular angular intervals to each other, wherein each pair of adjacent tips (46) is connected by curved sections (48) which protrude from the adjacent tips (46) into the direction of the logitudinal axis (17) and which coincide in a common summit (50).
17. Securement flange according to any of claims 12 to 16, characterized in that at least one of the two regions of the securement section comprises a plurality of protrusions at predetermined locations which are mated to respective recesses (56, 58) of the drive shaft (16) for receiving same.

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