EP1542835A1

EP1542835A1 - Tool holder

Info

Publication number: EP1542835A1
Application number: EP03740049A
Authority: EP
Inventors: Karl Frauhammer; Heinz Schnerring; Joerg Friedrich; Andreas Strasser
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2002-09-18
Filing date: 2003-05-30
Publication date: 2005-06-22
Anticipated expiration: 2023-05-30
Also published as: DE10243288B4; CN100400242C; JP2005538858A; EP1542835B1; CN1652902A; DE10243288A1; WO2004028751A1

Abstract

The invention relates to a tool holder (10), in particular for a hammer drill or chisel drill. Said holder comprises an insertion opening (14) for receiving a tool shaft (16), at least one actuator (22) for axially locking or releasing the tool shaft (16) in the insertion opening (14), said actuator (22) being displaced between a locked position and a released position, in addition to at least one clamping mechanism (34-44) for clamping the actuator (22) in the released position and/or in the locked position. The invention is characterised in that the clamping mechanism (34-44) is covered radially on its exterior relative to the insertion opening (14) by a cover (46), in order to prevent contamination and wear by abraded material.

Description

tool holder

State of the art

The invention is based on a tool holder according to the preamble of claim 1, in particular for a rotary or chisel hammer.

From DE 100 01 191 C2 a tool holder for a hammer drill or chisel hammer is known which enables an axial locking of a tool shank with a predetermined axial play. For this purpose, the tool holder has radially displaceable, roller-shaped locking elements which engage in a radially inner position in a groove-shaped recess in the lateral surface of the tool shaft and thereby axially lock the tool shaft, whereas the locking elements release the tool shaft in a radially outer position so that the Tool shank can be inserted or removed.

Furthermore, the known tool holder has an operating part in the form of a sleeve, which the locking element ß surrounds and can be moved axially by a user between a workpiece-side locking position and a tool-side unlocking position to lock or unlock the tool shank, wherein the control panel is biased by a spring in the direction of the workpiece-side locking position.

In the unlocked position of the operating part, the locking elements can move radially outward, so that the tool shaft can simply be pulled out or inserted from the insertion opening.

In the locking position of the operating part, however, the radial evasive movement of the locking elements is blocked by the sleeve-shaped operating part, so that the tool shaft is axially locked.

The Makita HR4000C hammer drill also has such a tool holder and, moreover, enables one-hand operation by the axially displaceable

Control panel is locked in the unlocked position by a locking mechanism. The user can therefore move the control panel axially with one hand from the locked position to the unlocked position, where the control panel engages. The user can then insert or remove the tool shank with the same hand without having to hold the control panel in the meantime. The sleeve-shaped operating part is locked in the unlocking position by a radially displaceable bolt, which, however, is free on the outside of the tool holder is accessible and therefore exposed to material abrasion, which leads to considerable wear.

Advantages of the invention

The invention encompasses the general technical teaching of protecting the locking mechanism for locking the operating part by a cover, so that the locking mechanism is not exposed to material abrasion, which leads to less wear.

The cover for the locking mechanism can, for example, have a sleeve that surrounds the locking mechanism on the outside, the sleeve preferably being made of an elastic material. This offers the advantage that the cuff can simply be pulled on and is then fixed due to its inherent tension.

However, it is also possible for the cover for the locking mechanism to be integrated in the displaceable operating part for locking or unlocking the tool shank. In the case of a sleeve-shaped operating part according to the prior art described at the outset, this can be achieved in that the locking mechanism is arranged inside the sleeve-shaped operating part. So here it forms

Control unit itself part of the cover for the locking mechanism.

In this variant of the invention, the sleeve-shaped loading ^"is used in part axially displaceably on a generally hollow cylindrical receiving body, wherein the receiving body of the tool testifies. It is advantageous here if the sleeve-shaped operating part surrounds the receiving body in an annular manner at least on one of its two end faces, in order to make it more difficult for material abrasion to penetrate into the interior of the sleeve-shaped operating part. The axially displaceable operating part therefore lies on one of its end faces, preferably slidingly on the lateral surface of the receiving body, in order to achieve a sealing of the operating part and to prevent the penetration of material abrasion.

To further improve the sealing effect between the sleeve-shaped operating part and the outer lateral surface of the receiving body, the operating part can have a wiper which rests on the outer lateral surface of the receiving body and when the sleeve-shaped operating part is axially displaced

Strips material abrasion, which is located on the outer surface of the receiving body.

In a preferred embodiment of the invention, the sleeve-shaped operating part is locked by a

Bolt that is essentially radially displaceable with respect to the insertion opening of the tool holder. The bolt can either assume a locking position or a release position, the bolt axially locking the sleeve-shaped operating part in the locking position, so that the user does not have to hold the operating part in place when inserting or removing the tool shank from the insertion opening, which makes comfortable one-hand operation possible is made possible. In contrast, in the release position, the sleeve-shaped control element is not locked and can therefore move move to its rest position, which is usually achieved by spring tension.

The bolt itself is preferably loaded by a spring element which holds the bolt in the locking position if the user does not bring the bolt from the locking position into the release division by manual intervention.

The power transmission from the spring element to the bolt can take place directly. Preferably, however, the force transmission from the spring element to the bolt takes place indirectly via a force transmission element in order to achieve good force transmission. The force transmission element can be, for example, a ball which is mounted in a radial bore and is biased radially inwards by the spring element.

The spring element for pretensioning the bolt can be a leaf spring, for example, but an annular spring is also suitable.

In a preferred embodiment of the invention, the locking position of the bolt lies radially inward with respect to the insertion opening, whereas the release position of the bolt lies radially outward with respect to the insertion opening. Here, the bolt thus moves in the radial direction from the outside in when the transition from the release position into the locking position with respect to the insertion opening. However, it is alternatively also possible that the locking position of the bolt lies radially on the outside with respect to the insertion opening, whereas the release position of the bolt lies radially on the inside with respect to the insertion opening. With this alternative arrangement, the bolt thus moves in the radial direction from the inside to the outside in the transition from the release division into the locking position with respect to the insertion opening.

In a preferred embodiment of the invention, the

Bolts for locking the sleeve-shaped operating part are mounted in a guide bore which runs radially with respect to the insertion opening in the receiving body and are thus axially fixed with respect to the receiving body. In this case, the bolt is not moved in the axial direction when the sleeve-shaped operating part is displaced.

In this embodiment, the bolt engages in the locking position in a latching element which is arranged in the sleeve-shaped operating part, which can be, for example, an undercut or a receiving bore.

The sleeve-shaped control panel preferably has an axially extending groove on its inside, the

Bolt has a head which is guided axially in the groove. This prevents radial movement of the bolt outside of the unlocked position of the sleeve-shaped operating part. In contrast, in the unlocked position of the sleeve-shaped control part, the groove indicates the movement of the bolt the locking position is free, whereby the sleeve-shaped operating part is locked axially.

However, it is alternatively also possible for the bolt for locking the sleeve-shaped control part to be mounted in a guide bore which extends radially with respect to the insertion opening and therefore also to be carried along in the axial direction when the sleeve-shaped control part is displaced axially.

In addition, the invention also includes a machine tool with the tool holder according to the invention, which is, for example, a hammer drill or chisel hammer.

drawing

Further advantages result from the following description of the drawing. Exemplary embodiments of the invention are shown in the drawings. The drawing, 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 useful further combinations.

Show it:

1 shows a cross-sectional view of a tool holder according to the invention for a rotary hammer with a sleeve-shaped operating part in a locking position, 2 shows the tool holder from FIG. 1, the sleeve-shaped operating part being in an unlocked position,

Fig. 3 is a detailed view of a bolt guide of the tool holder according to Figures 1 and 2 and

4 shows a further detailed view of the bolt guide from FIG. 3.

Description of the embodiments

The cross-sectional views in FIGS. 1 and 2 show a tool holder 10 for a hammer drill, which is partially of conventional construction, so that to supplement the following description reference is made to the patent document DE 100 01 191 C2 already mentioned at the outset, the content of the present description in its entirety is attributable.

The tool holder 10 has an essentially hollow-cylindrical holder body 12 with a cylindrical insertion opening 14, into which a tool shaft 16 of a drill can be axially inserted in order to lock the drill in the tool holder 10.

The tool shank 16 is locked in the insertion opening 14 here by a plurality of roller-shaped locking elements 18, which are arranged so as to be radially movable in corresponding openings in the wall of the receiving body 12. The openings taper radially inwards with respect to the insertion opening 14 in order to prevent the locking elements 18 from inwards from the openings fall out when the tool shaft 16 is removed from the insertion opening 14.

The locking of the tool shank 16 is effected in that the locking elements 18 engage in axially extending grooves 20 in the outer lateral surface of the tool shank 16, so that the tool shank 16 is fixed in the tool holder 10 with a predetermined axial play. The axial play of the lock is determined by the ratio of the lengths of the locking elements 18 and the grooves 20.

Furthermore, the tool holder 10 has a sleeve-shaped control part 22 which can be displaced on the outer lateral surface of the holder body 12 between the locking position shown in FIG. 1 and the unlocking position shown in FIG. 2.

A spiral spring 24, which surrounds the control part 22 and the receiving body 12, acts on the operating part 22, the spiral spring 24 engaging on one side on a ring 26 on a shoulder of the receiving body 12 and on the other side on a radial projection 28 supports the outside of the control unit 22. The spiral spring 24 thus presses the operating part 22 into the locking position shown in FIG. 1, in which the tool shaft 16 is axially locked in the tool holder 10.

In the locking position shown in Figure 1, the control panel 22 prevents with its inside that the locking elements 18 can move radially outward to the To release the lock. Here, the inside of the operating part 22 is flush with the outer lateral surface of the receiving body 12.

If the user now pushes the control element 22 against the force of the spiral spring 24 into the unlocking position shown in FIG. 2, an annular recess 30 lies in the sleeve-shaped control element 22 on the outside over the openings of the locking elements 18. The locking elements 18 can therefore be in the unlocking position of the operating part 22 dodge radially outward, so that the tool shaft 16 can simply be pulled axially out of the insertion opening 14 or inserted into it.

A rubber sleeve 32 is arranged in the recess 30 of the operating part 22, which rests on the outer lateral surface of the receiving body 12 and seals the gap between the operating part 22 and the receiving body 12 in order to prevent the penetration of material abrasion or dirt.

In addition, the tool holder 10 enables convenient one-hand operation by locking the operating part 22 in the unlocked position. This offers the advantage that the user does not have to hold the operating part 22 in the unlocked position despite the pretension of the spiral spring 24.

The control part 22 is locked in the unlocking position by a bolt 34 which is in a guide bore which extends radially with respect to the insertion opening 14 the wall of the receiving body 12 is radially displaceably mounted.

On its inside, the operating part 22 has an axially extending guide groove 36 which is T-shaped in cross section, as can be seen in particular from the detailed representations in FIGS. 3 and 4. Furthermore, the bolt 34 has a bolt head 36, which is guided in the guide groove 36, radial movement of the bolt 34 with respect to the insertion opening 14 being prevented by the guide groove 36, as long as the operating part 22 is not in the unlocked position. The guide groove 36 in the operating part 22 opens at its workpiece end, as can be seen from the detailed illustration in FIG. 3. In the unlocking position shown in FIG. 2, the bolt 34 can therefore move radially inwards with respect to the insertion opening 14 until the bolt head 38 rests on the outer lateral surface of the receiving body 12, as shown in FIG. 2. In this locking position of the bolt 34, the bolt head 38 bears laterally against the outgoing boundaries of the guide groove 36, as a result of which the operating part 22 is axially locked. The user can then remove the tool shank 16 from the insertion opening 14 without having to hold the operating part 22 in the meantime, which enables comfortable one-hand operation.

The movement of the bolt 34 into the locking position is effected here by two ring springs 40, 42, which are arranged on the outside of the operating part 22 in a ring surrounding the plane, which is perpendicular to the longitudinal axis of the Insertion opening 14 extends, the two ring springs 40, 42 being axially spaced apart.

The two ring springs 40, 42 rest radially on the outside against a metal ball 44, which is arranged in a radially extending guide bore in the operating part 22, the metal ball 44 being radially displaceable in the guide bore. However, the guide bore for the metal ball 44 tapers radially inwards so that the metal ball 44 cannot fall out of the control part 22 inwards. In the unlocking position shown in FIG. 2, the two ring springs 40, 42 press the metal ball 44 radially inwards onto the bolt head 38, so that the bolt 34 is brought radially inwards into the locking position.

The locking of the bolt 34 is released by pushing the tool shank 16 axially into the insertion opening 14 such that the inner end face of the tool shank 16 presses against the free end of the bolt 34, whereby the bolt 34 is pressed radially outward until the bolt head 38 is finally again in the plane of the guide groove 36. The bolt head 38 then no longer blocks the outgoing grooves of the guide groove 36, so that the spiral spring 24 presses the operating part 22 axially in the direction of the locking position shown in FIG. 1.

Finally, the tool holder has an annular sleeve 46 made of rubber, which encloses the control part 22 at its tool-side end, the two ring springs 40, 42, the metal ball 44, the guide bore in the

Control panel 22 and the bolt 34 are covered. The man- cuff 46 prevents material abrasion or dirt from entering the control panel 22.

At its end on the tool side, the sleeve 46 surrounds the receiving body 12 in an annular manner, the sleeve 46 resting on the outer lateral surface of the receiving body 12 with a sealing lip. In this way it is prevented that material abrasion or dirt can penetrate through the annular gap between the operating part 22 and the receiving body 12.

At its end on the workpiece side, on the other hand, the collar 46 has a radially inwardly projecting, circumferential projection which, in the assembled state, lies in an annular circumferential groove on the outside of the control part 22, as a result of which the collar 46 is axially fixed on the control part 22.

The invention is not restricted to the preferred exemplary embodiments described above. Rather, a large number of variants and modifications are conceivable, which likewise make use of the idea according to the invention and therefore fall within the scope of protection.

reference numeral

10 tool holder

12 receiving bodies

14 insertion opening

16 tool shank

18 locking element

20 Groove in the tool shank

22 control panel

24 coil spring

26 ring

28 head start

30 Recess in the control unit 2 sleeve 4 bolts 6 guide groove 8 bolt head 0 ring spring 2 ring spring 4 metal ball 6 sleeve 8 leaf spring

Claims

Expectations

1. Tool holder (10), in particular for a hammer drill or chisel hammer, with an insertion opening (14) for receiving a tool shank (16), at least one operating part (22) for axially locking or unlocking the tool shank (16) in the insertion opening ( 14), the operating part (22) being movable between a locking position and an unlocking position, and with at least one locking mechanism (34-44; 48) for locking the operating part (22) in the unlocking position and / or in the locking position , characterized in that the locking mechanism (34 - 44; 48) is covered with respect to the insertion opening (14) in the radial direction on the outside by a cover (46), the cover (46) having an elastic sleeve which the locking mechanism (34 - 44) at least partially covers the outside in the radial direction with respect to the insertion opening (14).

2. Tool holder (10) according to claim 1, characterized in that the operating part has an axially displaceable sleeve with respect to the insertion opening, the sleeve being part of the cover for the locking mechanism (48) and the locking mechanism (48) in the radial direction covers the insertion opening on the outside.

3. Tool holder (10) according to at least one of the preceding claims, characterized in that the operating part (22) has a sleeve which is axially displaceable with respect to the insertion opening (14) and the locking mechanism (34-44; 48) has a sleeve with respect to the insertion opening ( 14) has a radially displaceable bolt (34), at least one spring element (40, 42, 48) being provided for pretensioning the bolt (34) in the direction of a locking position.

4. Tool holder (10) according to claim 3, characterized in that the spring element is an annular spring (40, 42) or a leaf spring (48).

5. Tool holder (10) according to claim 3 and / or claim 4, characterized in that with respect to the insertion opening (14) in the radial direction between the bolt (34) and the spring element (40, 42, 48), a transmission element (44 ) for a power transmission from the spring element (40, 42, 48) to the bolt (34).

6. Tool holder (10) according to claim 4 and / or claim 5, characterized in that the transmission element (44) is substantially spherical.

7. Tool holder (10) according to at least one of claims 3 to 7, characterized in that the bolt (34) with respect to the insertion opening (14) is axially fixed and radially displaceable, the sleeve for positively engaging the bolt (34) in the Unlocking position has a locking element.

8. Tool holder (10) according to claim 7, characterized in that the sleeve has an axially extending groove (36) with respect to the insertion opening (14), in which the bolt (34) is mounted radially fixed with respect to the insertion opening (14).

9. Machine tool with a tool holder (10) according to at least one of the preceding claims.