EP3476539A1 - Tensioning device and handheld machine tool - Google Patents

Abstract

Clamping device (10) for axially (AR) bracing a tool disk (300) on a flange (30) associated with a drive spindle (20) of a handheld power tool (100), wherein the tensioning device (100) has a screw (2) which, for clamping the tool disk (300) is screwed into an internal thread (22) of the drive spindle (20), wherein the screw (2) is mounted in a coupling module (1) of the clamping device (10), wherein the coupling module (1) has an inner contour (16 ), which in the circumferential direction (U) positively against rotation with the drive spindle (20) is paired or paired.

Description

The present invention relates to a clamping device for the axial clamping of a tool disk to a drive spindle of a hand tool machine associated flange. The clamping device has a screw which, for clamping the tool disk, is to be screwed into an internal thread of the drive spindle.

Such tensioning devices are basically known from the prior art. Also known from the prior art are clamping devices with a clamping nut, in particular designed as a two-hole nut, which are to be fastened with a corresponding tool on the drive spindle. However, the present invention relates to another class of clamping devices, namely those having a screw which is to be screwed into an end-side internal thread of the drive spindle.

It is an object of the present invention to provide a clamping device, which counteracts a self-release of the clamping device - and thus a loosening of the tool disk during operation of the power tool.

The object is achieved in that the screw is mounted in a coupling module of the clamping device, wherein the coupling module has an inner contour which is positively coupled in the circumferential direction against rotation with the drive spindle or pairable.

The tensioning device according to the invention has the advantage that it can not tighten or loosen during operation of the power tool, because the coupling module is part of the clamping device mating positively against rotation with the drive spindle paired. This as a counterpart to a preferably positively against rotation paired with the drive spindle flange.

It has proven to be advantageous if the inner contour of the coupling module is designed as a hexagonal profile. Preferably, a corresponding outer contour of the drive spindle is formed as an external hexagon. Alternative form-fit torsion-proof pairings, for example in the sense of a positive shaft-hub connections, can be used.

Preferably, the internal thread of the drive spindle is an end-side internal thread. The internal thread can be in the axial direction with respect to a top surface of the drive spindle be reset. Preferably, the screw is in the axial direction on the coupling module, in particular with respect to the cylindrical portion of the coupling module addition. The coupling module is preferably cylindrical. Preferably, the coupling module has a cylindrical portion which can protrude through a central opening of the tool disk. The cylindrical section of the coupling module can protrude into a central opening of the flange.

In a preferred embodiment, the clamping device has a hand knob, which is formed in the circumferential direction positively against rotation with the screw. As a result, a particularly simple handling of the clamping device is possible. An additional assembly tool, such as a mounting key, can be dispensed with.

In a particularly preferred embodiment, the clamping device on a clamping member which can be acted upon by means of the coupling module with an axial clamping force, so as to clamp the tool disk against the flange. Particularly preferably, the tendon is formed as a spring plate. The spring plate may be disc-shaped.

In a preferred embodiment, the screw is mounted on a roller bearing in the coupling module. Characterized in that a Kopfreibung of the clamping element can be reduced by means of the rolling bearing, an increased clamping force of the clamping device is realized.

Particularly preferably, the rolling bearing is designed as angular contact ball bearings. The angular contact ball bearing preferably has a contact angle between 35 ° and 45 °. The contact angle can be 40 °. Due to the diagonal pressure angle of the rolling elements, in particular in an angular contact ball bearing, the clamping device wedged radially towards the end of the clamping operation. This provides an increased safeguard against unintentional release.

If the tensioning device has a tendon in the form of a spring plate, which is preferred, the tensioning device is given an increased insensitivity to settlement, since the spring plate is in frictional connection with the tool disc, which compensates for thermal expansion.

In a further embodiment, the tensioning device has an elastomeric ring, which is preferably arranged between a head of the screw and a collar of the coupling module. Alternatively or additionally, the clamping device may comprise a retaining ring, by means of which the coupling module is held on the screw.

According to an advantageous embodiment of the present invention may be provided instead of an elastomeric ring and a plate spring. The diaphragm spring can serve to To seal a grease space between the screw head and the collar of the coupling mode. In addition, the plate spring can also axially bias the hand knob.

It is according to a further advantageous embodiment further possible that instead of the elastomeric ring, a combination of elastomeric element and mechanical spring is used.

It has proven to be advantageous if the tendon is held by means of a locking ring on the coupling module.

In a further preferred embodiment, the clamping device has a stop, via which a deflection of the clamping member is indirectly or directly limited. Preferably, the stopper is formed as an annular collar and arranged between the spring plate and the male tool disc. If the tool disk comes into contact with the stop in the course of the clamping operation, a deflection of the spring element in the axial direction is limited.

The object is also achieved by a hand tool, preferably in the form of a grinder or cutting grinder, with a drive spindle having a preferably end-side internal thread, and with a clamping device of the type described above. The drive spindle has an outer contour which is positively against rotation in the circumferential direction with the Inner contour of the coupling module is paired or mating.

It has proven to be advantageous if the hand tool comprises a flange which is connected by means of a rotation in the circumferential direction positively against rotation with the drive spindle or connectable.

The hand tool according to the invention can advantageously be further developed by the features explained with reference to the clamping device in a corresponding manner.

Further advantages will become apparent from the following description of the figures. In the figures, various embodiments of the present invention are shown. The figures, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Fig. 1

ein bevorzugtes Ausführungsbeispiel einer erfindungsgemäßen Spannvorrichtung zusammen mit einer Werkzeugscheibe und einer Handwerkzeugmaschine;

Fig. 2

die Spannvorrichtung der Fig. 1 in Vorder- und Rückansicht;

Fig. 3

die Spannvorrichtung der Figuren 1 und 2 in Explosionsdarstellung;

Fig. 4

die Spannvorrichtung der vorgehenden Figuren in Schnittdarstellung;

Fig. 5

ein zweites Ausführungsbeispiel einer erfindungsgemäßen Spannvorrichtung im Teilschnitt; und

Fig. 5a

ein drittes Ausführungsbeispiel einer erfindungsgemäßen Spannvorrichtung im Teilschnitt.

In the figures, identical and similar components are numbered with the same reference numerals. Show it:

Fig. 1

a preferred embodiment of a clamping device according to the invention together with a tool disk and a power tool;

Fig. 2

the tensioning device of Fig. 1 in front and back view;

Fig. 3

the tensioning device of FIGS. 1 and 2 in exploded view;

Fig. 4

the clamping device of the preceding figures in sectional view;

Fig. 5

a second embodiment of a clamping device according to the invention in partial section; and

Fig. 5a

a third embodiment of a clamping device according to the invention in partial section.

EXAMPLES

A preferred embodiment of a tensioning device 10 according to the invention is shown in FIG Fig. 1 shown. The clamping device 10 serves to clamp a tool disk 300 in the axial direction AR. The tool disk 300 is to be clamped between the clamping device 10 and a flange 30, wherein the flange 30 is associated with a drive spindle 20 of a hand tool 100.

The flange 30 has an anti-rotation 24 in the form of a lateral recess, so that the set on the drive spindle 20 flange in the circumferential direction U positively against rotation with the drive spindle 20 is connected.

Again Fig. 1 can be removed, the clamping device 10 has a screw 2, which is to be screwed for clamping the tool disk 300 in an end-side internal thread 22 of the drive spindle 20. On the underside of the tensioning device 10, a coupling module 1 of the tensioning device 10 provided according to the invention can already be seen, in which the screw 2 is mounted centrally. The inner contour according to the invention will be discussed later with reference to Fig. 2 explained in more detail.

Again Fig. 1 can be removed, the clamping device 10 has a hand knob 3. This serves for manual screwing of the screw 2 in the internal thread 22 and thus for axial clamping of the tool disk 300 between the clamping device 10 and flange 30. The hand knob 3 is formed in the circumferential direction U positively against rotation with the screw 2. For this purpose, a head of the screw 12 by way of example has an outer hexagonal contour which is embedded in a corresponding hexagonal inner contour of the hand knob 3. As an alternative to the hexagonal contour, however, almost any other suitable contour can be used.

Again Fig. 1 can be removed below, the drive spindle 20 has an outer contour, which in the present example is formed as a hexagonal profile. A form-fitting twist-proof mating between coupling module 1 and outer contour 26 is achieved when the clamping device 10 is tensioned, the coupling module 1 at least partially through a central opening 301 of the tool disk 300th protrudes.

Fig. 2 now shows the tensioning device 10 of Fig. 1 in plan view ( Fig. 2A ) as well as in bottom view ( Fig. 2B ).

Good to recognize in Fig. 2A is already described hand knob 3, in which the screw 2 is embedded by means of its head 12 in the circumferential direction positively against rotation. The Clamping device 10 also has a clamping member, which is formed here by way of example in the form of a plate-shaped spring plate 4. By means of the spring plate 4, the actual clamping force is applied to the tool disk 300.

In Fig. 2B the central screw 2 of the clamping device 10 is clearly visible. The screw is mounted in the coupling module 1 of the clamping device 10, more precisely, the screw 2 is mounted coaxially in the coupling module 1. Good to see is a cylindrical portion 13 of the coupling module 1, wherein the cylindrical portion 13 at least braced tool disc 300 at least partially through the central opening 301 of the tool disk 300 (see. Fig. 1 ) runs.

According to the invention, the coupling module 1 has an inner contour 16 which, in the circumferential direction UR, is secured against rotation with the drive spindle 20 in a form-fitting manner (cf. Fig. 1 ) can be paired. According to the illustrated preferred embodiment, the inner contour 16 is formed as a hexagonal profile.

Fig. 3 now shows the preferred embodiment of the clamping device 10 of the preceding figures in an exploded view. In the upper area of the Fig. 3 to recognize the screw 2 with its screw head 12, which has an example of an external hexagonal contour. In the lower part of a thread 14 of the screw 2 can be seen, which in an internal thread (see. Fig. 1 : Internal thread 22) is screwed. The screw 2 is mounted in the coupling module 1 via a roller bearing, preferably an angular contact ball bearing 5.

Among other things, an elastomer ring 6 shown underneath the hand knob 3 serves to hold the outer contour of the screw head 12 within a corresponding inner contour of the hand knob 3. This is particularly evident from FIG Fig. 4 seen. Below the elastomeric ring 6 to recognize the coupling module 1, which also has a collar 11 in addition to the already described cylindrical portion 13 and the hexagonally shaped inner contour 16. The collar 11 is designed and provided to transmit an applied over the hand knob 3 and the screw 2 clamping force on the spring plate 4.

The coupling module 1 is in the circumferential direction U positively against rotation with the spring plate 4 paired, paired in the assembled state. This is preferably true for all embodiments. For this purpose, the coupling module 1 below the collar 11 of the coupling module 1 on a module contour 19, which corresponds to an inner contour of the spring plate 4. By way of example, the module contour 19 is designed as an external square. Detect below the coupling module 1 is a retaining ring 7, by means of which the coupling module 1 is held on the screw 2.

The tendon, here in the form of the spring plate 4, is held by means of a locking ring 8 on the coupling module 1. The function of the clamping device 10 according to the invention will now be with reference to Fig. 4 be explained in more detail.

First, if necessary, the flange 30 (see. Fig. 1 ) is placed on the drive spindle 20 of the power tool 100. By the anti-rotation 24, the flange 30 in the circumferential direction U positive fit against rotation with the drive spindle 20 is connected. Thereafter, the cutting disk 300 is inserted. When applying the clamping element 10 comes first, the inner contour 16 (in this case hexagon socket) with the outer contour 26 of the drive spindle 20 in a form-fitting rotation-proof engagement. Preferably, this is done before the thread 14 of the screw 2 enters the internal thread 22 of the drive spindle 20.

When screwing in the tensioning device 10, a manual force is transmitted to the screw 2 via an operating element, which is designed, for example, as a hand knob 3. This is due to the fact that the head 12 of the screw 2 is embedded in the hand knob 3 in a positively locking manner in the circumferential direction. At the latest, when the spring plate 4 rests on the tool disk 300, the head 12 of the screw 2 slides over the angular contact ball bearing 5 relative to the coupling module 1 until at the end of the spring travel of the spring plate 4 prevails a radial strain. It thus acts both an axial and radial tension between the head 12 of the screw 2 to the coupling module 1, wherein in particular the radial strain generates the higher holding effect. The radial clamping is achieved in that the preferably provided roller bearing is designed as an angular contact ball bearing 5, which by way of example a contact angle BW of 40 ° (see also Fig. 5 ) having. As a result, a Kopfreibung the screw head 2 is increased, which avoids unintentional release of the clamping device 10.

The located between the coupling module 1 and the head 12 of the screw 2 elastomeric ring 6 presses on the one hand a portion of the knob 3 against the screw head 12. And thus serves to avoid a lubricant outlet from the Wälzkörperraum. On the other hand, the elastomer ring 6 holds in interaction with the retaining ring 7, the coupling module 1 on the screw 2. An illustrated below the spring plate 4 circlip 8 is used to hold the clamping plate 4 on the coupling module. 1

Again Fig. 4 can be removed, the clamping force is transmitted in the axial direction AR via a collar 11 of the coupling module 1 on the spring plate 4 and from there to the tool disk 300. Relative to the circumferential direction UR, the spring plate 4 and the coupling module 1 are positively coupled to each other in a rotationally secure manner.

Fig. 5 Finally, shows a further preferred embodiment of a clamping device 10 according to the invention. Again, a rolling bearing in the form of an angular contact ball bearing 5 is provided between coupling module 1 and screw 2, which has a contact angle BW of 40 ° (for example). In contrast to that with respect to Fig. 4 described embodiment, the embodiment of the Fig. 5 a stop 9, via which a deflection of the clamping member, which is designed here as a spring plate 4, can be limited.

In Fig. 5a another preferred embodiment of a clamping device 10 according to the invention is shown. Again, between the coupling module 1 and screw 2, a rolling bearing in the form of an angular contact ball bearing 5 is provided, which has a contact angle BW of 40 ° (by way of example). In contrast to that with respect to Fig. 4 described embodiment, instead of the elastomeric ring 6 for sealing and biasing the hand knob 3, a plate spring 6a is provided. Again Fig. 5a can be seen, the plate spring 6a is positioned between an underside of the handle knob 3 and an upper side of the collar of the coupling module 11, so that the spring force of the plate spring 6a acts on the underside of the handle knob 3 and the top of the collar of the coupling module 11. The disc spring 6a thus positioned serves inter alia to hold the outer contour of the screw head 12 within a corresponding inner contour of the hand knob 3.

LIST OF REFERENCE NUMBERS

1

coupling module

2

screw

3

hand knob

4

spring plate

5

Angular contact ball bearings

6

elastomer ring

6a

Belleville spring

7

retaining ring

8th

circlip

9

attack

10

jig

11

Collar of the coupling module

12

Head of the screw

13

cylindrical section

14

thread

16

inner contour

19

module outline

20

drive spindle

22

inner thread

24

twist

26

outer contour

30

flange

100

Hand tool

300

tool disk

301

central passage opening

AR

axial direction

BW

contact angle

U

circumferentially

Claims (11)

Clamping device (10) for axially (AR) bracing a tool disk (300) on a flange (30) associated with a drive spindle (20) of a handheld power tool (100), wherein the tensioning device (10) has a screw (2) which, for clamping the tool disk (300), in an internal thread (22) of the drive spindle (20) is screwed,
characterized in that the screw (2) in a coupling module (1) of the clamping device (10) is mounted, wherein the coupling module (1) has an inner contour (16) in the circumferential direction (UR) positively against rotation with the drive spindle (20). paired or pairable. Clamping device (10) according to claim 1,
characterized in that the clamping device (10) has a hand knob (3) which is formed in the circumferential direction (UR) positively against rotation with the screw (2). Clamping device (10) according to claim 1 or 2,
characterized in that the tensioning device (10) has a tensioning member, preferably in the form of a spring plate (4), which can be acted upon by means of the coupling module (1) with an axial clamping force to so the tool disk (300) against the flange (30) tense. Clamping device (10) according to one of the preceding claims,
characterized in that the screw (2) via a rolling bearing in the coupling module (1) is mounted. Clamping device (10) according to claim 4,
characterized in that the rolling bearing is designed as angular contact ball bearing (5), wherein the angular contact ball bearing preferably has a contact angle (BW) between 35 degrees and 45 degrees. Clamping device (10) according to one of the preceding claims,
characterized in that the tensioning device (10) comprises an elastomeric ring (6) which is preferably arranged between a head (2 ') of the screw (2) and a collar (11) of the coupling module (1). Clamping device (10) according to claim 6,
characterized in that the tensioning device (10) has a retaining ring (7) by means of which the coupling module (1) is held on the screw (2). Clamping device (10) according to one of claims 3 to 7,
characterized in that the tensioning member is held by means of a securing ring (8) on the coupling module (1). Clamping device (10) according to one of claims 3 to 8,
characterized in that the tensioning device (10) has a stop (9) via which a deflection of the tensioning member is indirectly or directly limited. Powered hand tool (100), preferably in the form of a cut-off wheel, with a drive spindle (20) having an end-side internal thread (22) and with a tensioning device according to one of the preceding claims, wherein the drive spindle (20) has an outer contour (26), in the circumferential direction (UR) positively against rotation with the inner contour (16) of the coupling module (1) is paired. Hand tool (100) according to claim 10, comprising the flange (30) by means of an anti-rotation device (24) in the circumferential direction (U) positively against rotation with the drive spindle (20) connected or connectable.

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