GB2174934A

GB2174934A - Toolholder

Info

Publication number: GB2174934A
Application number: GB08608552A
Authority: GB
Inventors: Johann Kaltenecker; Gerhard Meixner; Karl Wanner
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1985-05-08
Filing date: 1986-04-08
Publication date: 1986-11-19
Also published as: DE3516542C2; JPS61257731A; JP2515298B2; GB8608552D0; CH669132A5; DE3516542A1; GB2174934B

Abstract

A toolholder for coupling a tool particularly a hammer drill, to a hand-operated machine tool has the tool shank (9) received in a coupling sleeve (6) containing longitudinal slots (12) in which approximately radially directed locking pins (41), engaging into a recess (10) of the tool shank (9) for axial locking, are contained so as each to be pivotable about an approximately tangential pivot axis, and to be movable generally radially. The coupling sleeve (6) is surrounded by a relatively axially displaceable sliding sleeve (7) with a control sleeve (23) to provide control surfaces (19 to 21). For tool release, the sliding sleeve (7) is axially displaced, and the locking pins (41) can move radially outwardly and come free of the tool shank (9). When the tool is inserted, the locking pins (41) swing out counter to the effect of springs (32), and then swing into the recess (10) with a locking action under the spring effect. Drive member (2) provides rotary drive to the tool, while drive member (3) provides hammer blows. <IMAGE>

Description

SPECIFICATION Tooiholder State of the art The invention starts from atoolholder according to the pre-characterising clause of the main claim. Such a tool holder is known, but has many defects. Thus, there are difficulties in locking an inserted tool shank automatically when the depths of the recesses in the tool shank do not exactly match the dimensions in the toolholder. Furthermore, it is only possible to in serttoolsofwhichthearrangementand number of recesses contained match the corresponding positioning, shape and number of locking bodies in the toolholder.If, for example, the tool holder is designed to fit tool shanks with a continuous encircling recess, only tools of a corresponding type can be locked in this tool holder, but not, for example, tools with a hexagonal shank or with individual axial longitudinal grooves, and vice versa.

Advantages ofthe invention In contrast to this, the tool holder according to the invention, with the characterising features ofthe main claim, has the following advantages. Because the locking pin is mounted pivotably, itis possible, by pivoting, to match the locking pins automatically to the particulartype and particular depth of therecesses in the tool shank. Atthe same time, even those tools having fewer recesses in theirshankthan the toolholder contains locking bodies can be locked perfectly. Thus, for example, any tool containing only two axial recesses in the tool shank can be locked, even when the tool holder has four locking pins.In this case, the remaining two locking pins stay in their radially swung-out position and rest on the outer periphery ofthetool shank, whilstthe other two locking pins engage radially into the recesses of the tool shank and lock the latter axially. Tool shanks with a continuous encircling recess can also be locked by means of the tool holder in exactly the same way as tool shanks with a hexagonal cross-section and, for example, with only one longitudinal recess in the region of one face ofthe hexagon. Consequently, many differenttypes oftool shanks can be locked auto maticallywith the same toolholder. Atthe sametime, it is genuinely possible to operate thetoolholder onehanded to lock it automatically.Because the locking pins are automatically matched to the particular depth of the recesses, even tool shanks already showing signs of wear can also be locked. In general terms, the tool holder is simple, compact, light- weight and space-saving and at the same time is functionally reliable and inexpensive. It only consists of a few individual parts which, moreover, can also be produced economically, for example, by sintering, extrusion orthe like, thus additionally lowering the costs. It can be made rotationally symmetrical, with the resu It that the production costs are reduced even further. Moreover, the tool holder is convenientfor resetting, so that hand-operated machine tools hav ing toolholders of a different design can be reset easily and quickly by attaching the toolholder according to the invention.

Advantageous developments and improvements ofthe toolholder indicated in the main claim are possible as a result of the measures listed inthefollow- ing claims 2 to 20 Drawing An exemplary embodiment of the invention is illustrated in the drawing by means of several Figures and explained in detail in the following description.

In the drawing: Figure 1 shows a diagrammatic axial longitudinal section through a toolholderwith drive members of a hammer drill and/or sledge hammer, in the locking position, the locking body in the lower part being omitted forthe sake of greater clarity, Figures2and 3 show respectively a diagrammatic section along the iine Il-Il in the locking position and along the line Ill-Ill in the release position in Figure 1, specifically the upper half of the toolholder, Figures4and 5show respectively a diagrammatic axial longitudinal half-section through part of the toolholderwith drive members, corresponding to Figure 1, specifically in the state before the locking of an insertedtool shankand in thestate during the release and before the extraction of the latter.

Figure 6shows a diagrammatic perspective exploded representation of onlythe cage ofthetoolholder.

Description of the exemplary embodiment Of hammerdrill and/orsledge hammer(not shown) the drawings only illustrate its drive member 2, projecting at the front from the fixed housing 1 and producing the rotarydrive, and an innerdrive member 3 which executes the axial hammer below.

Atoolholder 5 is firmly attached releasablytothe housing 1. This toolholder 5 has a coupli ng sleeve 6 carrying, at the end on the right in Figures 1,4 and 5, a mounting flange 4which is fastened to the drive member 2 by means of screws. The coupling sleeve 6 consists, for example, of steel. Guided on its outside is an axially movable sliding sleeve 7 which consists of metal or especially of plastic, as shown. The coupling sleeve 6 contains inside it either a cylindrical or, as shown here, a hexagonal receiving bore 8, into which a tool shank 9 of a tool can be inserted. The tool shank 9 can have a corresponding hexagonal cross-section or, as shown here, a circula r corss- section.The tool consists, for example, of a drill or a bit, both of which can be received in the toolholder 5.

The tool shank9 illustrated has, at its rear end, a conventional toothed portion which is received in an associated toothed receptacle of the drive member 3.

Instead of the rotary drive via the coupling sleeve 6, the rotary driveforthe tool shank 9 can also be ensured, at the same time, by means of the drive member 3. In this case, both the axial hammer blows and the rotary drive torques are transmitted via the latter.

In the exemplary embodiment illustrated, there is, on the outer peripheral surface ofthe tool shank 9, a continuous encircling recess 10 which is closed at both ends in the axial direction and which has a substantial axial length. The recess 10 serves for locking the inserted tool shank 9. Locking bodies 11 engage into the recess 10 all round. These are held in the coupling sleeve 6 so as to be movable in a radial plane. The locking bodies 11 are located at equal peripheral angulardistancesfrom one another. In the exemplary embodiment illustrated, there are six locking bodies 11 altogether. However, alternatively, there can also be fewer or even more, for example eight locking bodies.

Each locking body 11 is contained in a longitudinal slot 12 of a cage 13 which is an integral component of the coupling sleeve 6 and which, like this, is rotationally symmetrical. Each longitudinal slot 12 extends approximately parallel to the axis and has radially on the inside an open passage orifice 22 for the particular locking body 11. Consequently, these can pro ject inwards into the recess 10 ofthe tool shank 9.

Movement in the radial plane ofthe locking bodies 11 is caused as a result ofthe insertion ofthetool shank 9 during locking or as a result of the shift ofthe slid- ing sleeve 7 from the locking position, shown in Figure 1, into the release position, shown in Figure 5 for releasing it, and as a resultoftherelativedis- placement of the tool shank 9, innerworking surfaces ofthe sliding sleeve 7 and/or of a control sleeve 23 coupled to it interacting with the locking bodies 11 to lock and release these.

The control sleeve 23 surrounds the coupling sleeve 6 in the region ofthe cage 13 and is guided so as to be axially displaceable there. It is surrounded by the sliding sleeve 7, againstthe inner annular collar 24 of which the control sleeve 23 rests by means of the end on the left in Figure 1, underthe effect of a restoring spring 28 which at its other end is supported relative to the coupling sleeve 6 on a stop ring 34 located on the latter.

Each locking body 11 has a locking pin 41 forex- ample of round cross-section, which is directed at least essentially radially and towards the tool shank9 and which, art a radial distance from its locking end 42 engaging into the recess l0ofthetool shank9,car- ries a transverse bearing extension 43 in the form of a, for example, cylindrical crosspin which can be in one piece with the locking pin 41.

Each locking body 11 thereby has an approximately T-shaped form (Figures 2 and 6). The locking pin 41 is mounted in the cage 13 via the bearing extension 43 so as to be pivotable about an app roximatelytangential pivot axis 44 (Figure 2 and 6).

For release, each locking pin 41 can be shifted out of its locking position (Figures 1 and 2), in which it is supported radially in the region of the pivot axis 44, approximately radially into a release position (Figure 51, in which the locking end 42 moves free ofthe re cess l0inthetoolshank9.

The inner regiOn ofthe sliding sleeve 7 and the control sleeve 23 is stepped on the inside in the region adjacentto the locking bodies 11. An inneran nular surface provided at the front end of the control sleeve 23 atthe same time forms a first control surface 19. This is followed axially towards the left in Figure 1 by a sloping step-transition surface 20 and an adjoining second inner annular surface of larger diameter, these forming a second control surface 21.

The step-transition surface 20 is likewise partofthe control sleeve 23 and is formed there by a slope which, as seen in the direction of insertion ofthetool shank 9, descends obliquely from the control surface 21 towards the first control surface 19 of smaller radial dimension. In the locking position shown in Figure 1,the first control surface 19formsa radial stop for all the locking bodies 11 which, in this radial position, arethus prevented from escaping in the radial direction. In contrast to this, in the release position shown in Figure 5, the step-transition surface 20 forms a control surface which engages in the region ofthe bearing extension 43 ofthe locking pin 41 and which forces the latter radially inwards out ofthe release position into the locking position.

As can be seen,the step-transition surface 20 and the control surface 21 precede the first control surface 19, and the step-transition surface 20 forms the transition from the first control surface 19 of smaller radial dimension to the control surface 21 having a larger radial dimension.

Each locking pin 41 is subjected to an axial spring force which is directed counterto the direction of in sertion ofthetool shank9 and countertotheswing- out direction ofthe locking pin 41. This spring force is exerted on each locking pin 41 by a spring 32 which is retained on the cage 13 and which is designed especially as a curved spring leafwhich, extending from a carrier35 in the form of an annular segment, engages into the particular longitudinal slot 12 assigned to it and by means of its free spring end engages on the locking pin 41 nearthe locking end 42.

Each carrier35 in theform of an annularsegmentis inserted in an outer annular groove 36 of the coupling sleeve 6, in such awaythatthespring 32 curving awayfrom it projects into the associated longitudinal slot 12. On the outside, each carrier 35 in the form of an annular segment is surrounded by the control sleeve 23 resting on it and is thus fixed radially and axially.

At the end on the left in Figure 1, each longitudinal slot 12 is closed by means of a terminal end face 15 which descends in the form of a wedge in the radial direction from outside inwards andtowardsthe inner passage orifice 22 ofthe longitudinal slot 12, and which forms a sloping bearing surface forthe locking pin 41. Because ofthe slope of the end face 15, in the locked position (Figure 1) the locking pin 41 extends obliquely in a corresponding way, the locking pin 41 being pressed against the end face 15 via the spring 32 and being held resiliently in this position.

At the end of the individual longitudinal slots 12 which is nearthe terminal end face 15, the cage 13, which forms an integral component ofthe coupling sleeve 6, has an outer annular groove 25which,for each longitudinal slot 12, forms a bearing receptacle forthe pivoting mounting ofthe associated locking pin 41. Each locking pin 41 is received in the annular groove 25 by means of its bearing extension 43, thus forming the pivot mounting forthe locking pin 41 for pivoting about the pivot axis 44.

To release the tool shank 9 locked in Figure 1, the sliding sleeve 7, together with the control sleeve 23, is shifted by hand to the right in Figure 1 counterto the effect ofthe restoring spring 28. As a result, the step-transition surface 20 and th control surface 21 come into the region of the locking bodies 11 and, because the radial dimension of the latter is greater than that ofthe first control surface 19, make it possible forthe locking pins 41 to move aside radially outwards, approximately in the direction of the pin axis, in the longitudinal slot 12. Sincethetool shank9 is pulled to release it, its chamfer, on the right in Figure 1, located at the end ofthe recess 10 passes into the region of the locking end 42 of each individual locking pin 41.Because of the slOping shape ofthis chamfer, each individual locking pin 41 is pushed out radially into the position shown in Figure 5. The tool shank 9 can be extracted completely. After that, the sliding sleeve 7, together with the control sleeve 23 is automatically returned into the initial position again by means ofthe restoring spring 28, and via the sloping step-transition surface 20, engaging on the upper end ofthe locking pins41 and on their bearing extension 43, the individual locking bodies 11 are shifted radially back into the initial position according to Figure 1 again in the longitudinal slot 12 and, in this position, are pressed againstthe end face 15 underthe effect ofthe spring 32.

When the tool shank 9 is inserted, the locking pins 41, locked to prevent them from escaping radially, are pivoted about the pivot axis 44 by means of its chamfer on the end face on the right in Figure 4, specifically with the springs 32 at the same time being compressed relatively hard. Thus, the locking end 42 projecting through the passage orifice 22 is pivoted until it no longer impedes the insertion ofthe tool shank 9. As soon as the recess 10 ofthetool shank 9 comes into the region of the swung-away locking ends 42 when the tool shank 9 is inserted,the locking pins 41 can swing back again about the pivot axis 44 under the effect of the compressed springs 32, and the respective locking ends 42 engage radially into the recess 10 to lockthetobl shank9.

When a tool shank 9, which, instead ofthe continuous encircling recess 10, has a hexagonal crosssection fitting into the receiving bore 8, with only one groove-shaped recess 10 in the region of one face of the hexagon, is used, when the tool shank9 is locked those locking pins 41 located in the region of the hexagon faces and not finding any recess 10 there remain in their released oblique pivoting position according to Figure 4. They then rest on the outer hexagon faces. Only the locking pin 41 located in the region of a groove-shaped recess lOon a face ofthe hexagon engages into the recess 10 with a locking action. As a result, even a tool shank9 of such a design can therefore be locked in the tool holder 5.Another advantage is that a tool shank 9 can be introduced in any rotary position into the toolholder Sand locked in the latter. The locking of the tool is carried out automatically and is secure. At the same time, the locking pins 41 are matched automatically according to whether there is a recess 10 at the particular location on the tool shank 9, and if so also to the depth of the respective recess 10. In this way, it is even possible to lock perfectly those tools which have a smal lernumber of recesses 10 inthetool shank9than there are locking pins 41 in the toolholder 5.It is also advantageous that it is also possible to use those tools which, when working with other machine tools, are already substantially worn on the tool shank 9 as regards the recesses 10 there. This is achieved be cause the locking pins 41 are matched automatically to the particular depth of the recesses 10. Further more, a practical benefit is that it is guaranteed that the tool shank can be inserted and locked automatic ally really with one hand. The tool locksnaps in auto matically. It is guaranteed thatthe inserted tool shank 9 is locked securely. In general,thetoolholderscan be produced simply and inexpensively and is oper ationallyrelaible. It consists of only a few individual parts which, moreover, can each be produced economically, for example by sintering, extrusion or the like. Afurther cost reduction is possible because of the rotationally symmetrical design. Existing handoperated machine tools can be reset to this principle without difficulty by attaching the tool holder.

Claims

1. Toolholderfor coupling percussion and/or rotating tools to hand-operated machine tools, preferably hammer drills and/or sledge hammers, with a coupling sleeve which, on the one hand, is connected to a drive membertransmitting a drive movement and belonging to the hand-operated machine tool and, on the other hand, receives a tool shank which has at least one recess which is closed on both sides in the axial direction and extends axially and into which engages at least one associated locking body held in the coupling sleeve so asto be movable in a radial plane, and with a spring-loaded sliding sleeve, surrounding the coupling sleeve with the locking body, and inner working surfaces which, to lock and release the at least one locking body, interact with the latter, characterised in that each locking body (11) has an at least essentially radially directed locking pin (41) which, at a radial distance from its locking end (42) engaging into the recess (10) ofthetool shank (9), is mounted so as to be pivotable about an approximately tangentiai pivot axis.

2. Toolholder according to Claim 1, characterised in that each locking pin (41) can be shifted out of its locking position, in whch it is supported radially in the region of its pivot axis (44), approximately radially into a release position, in which its locking end (42) moves free ofthe recess (10) in the tool shank (9).

3. Tool holder according to Claim 1, characterised in that the inner working surfaces are arranged on the sliding sleeve (7) and/or on a control sleeve (23) coupled to the sliding sleeve (7) and have a radial first control surface (19) approximately parallel to the axis and at least one further approximately radial control surface (20,21) stepped relative to the first control surface (19) and of a larger radial dimension, and in that each locking pin (41) is supported radially, in the region of its pivot axis (44), on the first control surface (19) in the locking position and radially in the region ofthe second control surface (20,21) in the release position.

4. Toolholder according to Claim 3, characterised in that the second control surface (20,210 precedes thefirstcontrol surface(19).

5. Toolholder according to Calim 5, characterised in that, as seen in the direction of insertion ofthetool shank (9), the sloping step;transition surface (20) which forms an oblique transition from the first con trol surface (190 to a radial control surfrace (21) of a larger radial dimension.

6. Toolholder according to Claim 5, characterised in that, as seen in the direction of insertion ofthetool shank (9),the sloping step-transition surface (20) descends obliquelyfrom the control surface (21) towardsthe first control surface (19) of smaller radial dimension.

7. Toolholder according to Claim 5 or 6, characterised in thatthe step-transition surface (20) forms a control surface which engages in the region of the pivot axis (44) ofthe locking pin (41) and which forcesthe locking pin (41) radially inwards from the release position into the locking position.

8. Tootholder according to one of claims 1 to 7, characterised in that the locking pin (41) is subjected to an axial spring force which is directed counterto the swing-out direction ofthe locking pin (41).

9. Toolholder according to one of Claims 1 to 8, characterised in that each locking pin (41) hasatrans- verse bearing extension (43) in the region of its pivot axis (44).

10. Toolholder according to Claim 9, characterised in that the bearing extension (43) is formed by a crosspin which is arranged atthe end ofthe locking pin (41) located opposite the locking end (42) and forms an approximate Twith the latter.

11. Tool holder according to claim 9 or 10, char- acterised in thatthe bearing extension (43) can be in one piece with the locking pin (41).

12. Toolholder according to one of Claims 1 to 11, characterised in that the coupling sleeve (6) has a cage (13), in which at least one locking pin (41) is retained so as to be pivotable about its pivot axis (44) and guided so as to be radially displaceable.

13. Toolholderaccording to Claim 12, char- acterised in that several locking pins (41), for example six or eight, are arranged in the cage (13) at equal peripheral angular distances from one another.

14. Toolholder according to Claim 12 or13, char- acterised in thatthe cage (13) has, for each locking pin (41), a longitudinal slot (12) approximately parallel to the axis, with a passage orifice (22), open radially inwards,forthe particular locking end (42) ofthe locking pin (41).

15. ToolholderaccordingtoClaim 14, char- acterised in that each longitudinal slot(12) is closed atthe end nearthe two control surfaces (19,20,21) by means of a terminal end face (15) which descends in the form of a wedge in the radial direction from outside inwards and towards the inner passage orifice (22) ofthe longitudinal slot (12) and forms a sloping bearing surface forthe locking pin (41).

16. Toolholderaccordingto one of Claims 12to 15, characterised in that the cage (13) has, atthe end ofthe longitudinal slots (12) whcih is neartheterminal end face (15), an outer annular groove (25) which for each longitudinal slot (12) forms a bearing receptacleforthe pivoting mounting ofthe bearing extension (43) especially of the crosspin, of the particular associated locking pin (41), the bearing extension (43), especiallythe crosspin, being received in the said bearing receptacle.

17. Toolholder according to one of Claims 8 to 16, characterised in that a spring (32) retained on the cage (13), especially a bent-round, approximately strip-shaped spring tongue, engages into each longitudinal slot (12) and by means of its free spring end engages on the locking pin (41), preferably nearthe locking end (42).

18. Toolholder according to one of Claims 12 to 17, characterised in that the cage (13) is an integral component of the coupling sleeve (6).

19. Toolholder according to one of Claims 3 to 18, characterised in that the control sleeve (23) surrounds the coupling sleeve (6), is coupled to the sliding sleeve (7) fixedly in terms of displacement and, when the sliding sleeve (7) is displaced counter to the effect of an axial spring force exerted on the sliding sleeve (7), can be displaced together with this from the locking position into the release position.

20. Toolholder according to one of Claims 3to 19, characterised inthatthefirstcontrol surface (19) and the sloping step-transition surface (20) are arranged on the control sleeve (23).

21. Atoolholder substantially as herein described with reference to the accompanying drawings.