GB2290043A

GB2290043A - Hand-held drill, particularly a hammer drill, with a combination chuck

Info

Publication number: GB2290043A
Application number: GB9511130A
Authority: GB
Inventors: Wilbert Reibetanz; Otto Baumann; Rolf Mueller; Heinz Neubert
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1994-06-07
Filing date: 1995-06-01
Publication date: 1995-12-13
Anticipated expiration: 2015-06-01
Also published as: DE4419825A1; JPH07328818A; BR9502693A; GB9511130D0; GB2290043B; CH690119A5

Description

2290043 Hand-held drill,--particularly a hammer drill, and a toolholder

for the same The starting point of the invention is a hand-held drill according to the generic definition of Claim 1, and a toolholder according to the generic definition of Claim 2. A hand-held drill is already known (DE 41 04 131 A1) in which the toolholder is screwed to a rotationally drivable rotary drive spindle of a hammer drill. Together with the rotary drive spindle the toolholder forms a common mounting unit, which after being screwed to the rotary drive spindle has to be Inserted Into the caning of the hand-held drill. If a fault develops in the toolholder during operation, the machine caning has to be is opened and the rotary drive spindle removed before the toolholder in extracted and replaced, which in very laborious. Any device provided to secure the rotary drive spindle cannot take the torque required for screwing and unscrewing the screw connection.

Advantages of the Invention The hand-held drill according to the invention, which has the characterizing features of Claim 1, and the toolholder having the characterizing features of Claim 2 have in contrast thereto the advantage that the tool- holder, while having a short axial overall length, can be connected to the rotary drive spindle In a particularly simple --n-er and, when necessary, can be detached again equally simply without the dismantling of the hand-held drill being necessary.

Through the measures specified in the dependent claims, advantageous developments and improvements of the hand-held drill indicated in Claim 1 and of the tool holder in Claim 2 are possible. The design of the unlock ing sleeve having at least one catch tongue which can be moved radially outwards in particularly advantageous. The provision of an annular shoulder engaging over the rolling elements of the thrust bearing prevents the rolling elements from falling out on the fitting of the unlocking sleeve and thus additionally facilitates assembly. Drawing Three exemplary embodiments of the invention are illustrated in the drawing and explained in greater detail in the following description. Figure 1 shows, as the first embodiment, a section through the toolholder of a hammer drill, Figure 2 shows a section through the unlocking sleeve of this toolholder, Figure 3 shows a partial section on the line 111-111 in Figure 2, Figure 4 shown a sectional representation of a toolholder according to a second exemplary embodiment, and Figure 5 shown a partial section through a thrust bearing according to a third exemplary embodiment.

Description of the Exemplary Embodi=ents

A toolholder 10 in arranged on the f =ant part at the tool end, shown in Figure 1, of a hammer drill. The toolholder 10 has a first tool scat 11 far tools having a round stem and a second tool scat 12 arranged further to the rear for tools having a fluted stem. A rotationally drivable, hollow cylindrical rotary drive spindle 14, in which in arranged a percussion element 15 drivable in an axial reciprocating movement, projects out of a part, designed an a clamp collar 13, of a machine easing of the hnTme= drill. A base body 17 provided with a central reception opening 18 is mounted on a stepped end 16 of the rotary drive spindle 14. With the aid of connecting elements 26 the base body 17 is joined to the rotary drive spindle 14 in such a manner an to be rotatable therewith but axially 4- vable thereon. The connecting elements 26 are designed in the exemplary embodiment as a total of two radial pins 19, of which only one is shown, turned by 60 degrees into the plane of the drawing, in Figure 1. The radial pins 19 are each arranged in a respective through hole 20 extending radially through the base body 17 and the wall of the rotary drive spindle 14. Locking balls or locking rollers may also be used an connecting elements 26.

A total of three recesses 21, which extend radially inwards in the forward direction and are 1 1 i unif o=aly of f act relative to one another in the circ=ferential direction and in each of which a clamp jaw 22 in alidably guided, are f ormed in the base body 17. The clamp jaws 22, of which there are a total of three but of which only one is shown in Figure 1, are provided on their rear side in the usual way with a toothing 23, which engages with a corresponding toothing of an adjust ing ring 24. Through the turning of the adjusting ring 24 in the circumferential direction the clamp jaws 22 can be adjusted Inside the recesses 21. The adjusting ring 24 in supported at the rear, in the direction of a drive motor (not shown) for the hammer drill, on the base body 17 by =cans of spherical rolling elements 29 and a support ring 30, and on the tool side in fastened at the front, relative to the base body 17, by a spacer alcove 31 and a securing ring 32. The adjusting ring 24, the rolling elements 29 and the support ring 30 thus form, a thrust bearing 28 of the first tool scat 11, a first bearing surface 71 being f ormed on the adjusting ring 24 and a second bearing surface 74 on the support ring 30.

An actuating sleeve 25 engages around the front part of the toolholder 10. The actuating alcove 25 In connected to the adjusting ring 24 for rotation therewith, so that through the turning of the actuating sleeve 25 the adjusting ring 24, and thus the clamp jaws 22, can be adjusted. The actuating sleeve 25 In supported at the rear on the spacer sleeve 31 and the adjusting ring 24, and at the front is axially secured by a securing ring 33. The actuating alcove 25 carries, In a groove 34, a dust cap 35 which dust-tightly closes the front part of the toolholder 10 in relation to a tool which in to be inserted therein.

The second tool seat 12 has on the wall of the reception opening 18 at least one strip-shapod rotary driver 36 for the rotational driving of an inserted tool having a fluted stem. A locking element 37 In alidably guided In a bore 3 9 extending in the base body 17 inwards and forwards obliquely to a longitudinal axis 38 of the toolholder 10, and engages radially In the reception opening 18. When the fluted-stem tool is inserted, the locking element 37 projects into an axially closed locking recess in the tool ate= and thus f astens the latter with limited axial slidability inside the second tool seat 12. on the rear side the locking element 37 is loaded by the force of a closing spring 40, which is supported at one end in an annular groove 46 in the base body 17 and at the other end on a closing ring 41. The closing ring 41 has a projection 42 extending axially forwards and having its end 43 bent over radially outwards, and is positively connected to the locking element 37.

The closing ring 41 la surrounded by an unlocking sleeve 44, which is axially alidable rearwards, carrying with it, by means of a shoulder 45, the closing ring 41 against the force of the closing spring 40. Because of the positive connection between the projection 42 and the locking element 37, the displacement of the unlocking sleeve 44 in the rearward direction ensures reliable extraction of the locking element 37 from the locking recess of the f luted-stem tool, so that a tool of this type can thereby be dependably unlocked.

The toolholder 10 is in addition provided with a locking pin 50, which projects through the base body 17 in a stepped radial bore 51 and by means of its =adially!=er end 52 engages in the reception opening 18. At its radially outer end 52 the locking pin 50 carries a toothing 53, which by means of a fluted-stem tool, when one is inserted into the second tool scat 12, is brought into engagement with a corresponding locking toothing 54 on the actuating sleeve 25, so that the actuating sleeve 25 and therefore also the adjusting ring 21 are then secured against rotation, whereby the clamp jaws 22 of the first tool seat 11 are then made i"vable. In the region of the locking pin 50 the unlocking sleeve 44 has a recess for the radial penetration of the locking pin 50.

The radial pins 19 serving to connect the base body 17 and the rotary drive spindle 14 are covered over z radially by the unlocking alcove 44 and thus prevented from slipping out of the through hole 20. To ensure that the unlocking sleeve 44 is capable only of axial movement and not of rotation, an axial groove 56, into which the radial pin 19 engages and which in closed at the front, is provided on its inner side. The front end 57 of the axial groove 56 forms a stop on the displacement of the unlocking sleeve 44 against the force of the closing spring 40. The radial pins 19 can similarly also be covered over by a securing part connected to the unlock ing sleeve 44.

In Figure 2 the =locking sleeve 44 In shown in greater detail. On the tool side the unlocking sleeve 44 has in the front region 44a an Inside diameter d which corresponds approximately to a maximum outside diameter of the base body 17 when the thrust bearing 28 in com pletely assembled (ace Figure 1), so that the unlocking sleeve 44 can be pushed from the front onto the base body 17 pre-assembled with the thrust bearing 28. in the region 44a having the smallest inside diameter d of the unlocking sleeve 44 catch means 60 are situated, which are composed of a plurality of (for example three) catch tongues 61 distributed on the periphery of the unlocking sleeve 44. The catch tongues 61, of which only one is shown in Figure 2, are formed by axial slits 62 in the unlocking sleeve 44 and are therefore resiliently movable radially.

The partial section shown in Figure 3 Illustrates one of the catch means 60. On the inner side of the unlocking sleeve 44 the catch tongue 61 has a projection 63, which on its face on the tool side has a catch surface 64 projecting radially inwards. When the unlock ing sleeve 44 Is installed (see Figure 1), the catch surface 64 of the projection 63 forms, together with a stop surface provided on the support ring 30, a stop 65 preventing axial displacement of the unlocking sleeve 44 in the forward direction. In order to facilitate the fitting of the unlocking sleeve 44, the projection 63 has on the machine side an inclined run-up surface 66. When m 1 the unlocking sleeve 44 in pushed on, the catch =cans 60 are then bent radially outwards and thereupon, af ter passing the support ring 30, lock axially behind the latter. The axial stop surface for the unlocking sleeve 44 can in addition also he arranged on the base body 17 or on some other component part Incapable of translational movement relative to said body.

The toolholder 10 in assembled in the following Tna.n.ner: The base body 17 Is pushed axially onto the rotary drive spindle 14, the thrust bearing 28 being already assembled. To prevent the rolling elements 29 fr= falling out radially when the actuating sleeve 29 in removed, they are partly covered over radially by a sleeve-shaped extension 67 of the spacer sleeve 31. The extension 67 extends axially over the adjusting ring 24. The locking element 37 and the radial pins 19 are then inserted into the corresponding holes 39, 20. The locking element 37 in at the same time also suspended positively by its rear head 47 in the projection 42 of the closing ring 41. The unlocking sleeve 44 In then fitted on the base body 17 from. the front and pushed axially rearwards in the correct rotational position. In so doing care must be taken that the radial pins 19 engage in the appertaining axial grooves 56 of the unlocking sleeve 44. As scan an the catch tongues 61 have passed the support ring 30, they spring back and for= the stop 65. The spring 40 urges the unlocking sleeve 44 into contact with the stop 65. Before the actuating sleeve 25 is fitted from the front and axially secured by =cans of the securing ring 33, the locking pin 50 in inserted into the radial bore 51. After the dust cap 35 has been fitted, the assembly of the toolholder 10 in complete.

A second exemplary embodiment of a toolholder 10 is illustrated in Figure 4. Like parts and parts having a like action are characterized by the same reference numerals, an in also the case in the third exemplary embodiment given further on. The main difference from the first exemplary embodiment consists in that the reception of tools having fluted stems In the second tool seat 12 takes place partly Inside the rotary drive SP4.ndl a 14. The reception opening 18 thus extends partly into the rotary drive spindle 14. The rotary drivers 36 are correspondingly arranged inside the rotary drive spindle 14. In this arrangement the locking element 37 engages through a window 70, which is provided In the wall of the rotary drive spindle 14, into the reception opening 18.

in addition, the thrust bearing 28 In slightly modified in comparison with the first exwWlary embod:L- -ant. An already mentioned, the rolling elements 29 of the thrust bearing 28 must for assembly reasons also be prevented from falling out radially when the actuating sleeve 25 is removed. In the exwWlary embodiment shmm in Figure 4 the adjusting ring 24 has for this purpose in the first bearing surface 71 an axial, ainnular circumferential depression 72, in which the rolling elements 29 roll. The rolling elements 29 are partly covered over radially by an external annular shoulder 73 and thus held between the adjusting ring 24 and the support ring 30.

Figure 5 shown another exwWlary embodiment of the thrust bearing 28, wherein the depression 72 Is arranged In the bearing surface 74 In the support ring 30. The rolling elements 29 are here correspondingly prevented from falling out by the external annular shoulder 73. Depressions 72 could of course also be arranged on both bearing surfaces 71, 74. A thrust bearing constructed in this manner can also be used in hammer drills and/or percussion hanners which are equipped only with a tool scat having clamp jaws 22 for round-stowmed tools. In particular it should be pointed out that the stop 65 for the unlocking sleeve 44 can also be formed directly on the base body 17 or on a c=Wanent part connected thereto in such a inanner an to be incapable of axial translational movement thereon.

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Claims

Claims

Eand-held drill, particularly a hammer drill, having a toolholder which in provided with a first tool seat (11), which has clamp jaws (22), for tools having a round stem and with a second tool seat (12), functionally separate therefrom, for tools having a fluted stem, and which has a base body (17) having arranged in it a reception opening (18) into which at least one locking element (37) for locking the tools having a fluted stem can engage radially, an inserted tool having a fluted stem being unlockable by means of an unlocking sleeve (44), characterized in that the toolholder (10) is provided with at least one connecting element (26) for the connection of the base body (17) to a rotationally drivable rotary drive spindle (14) of the hand-held drill, said connecting element being inserted partly into the base body (17) and partly into the rotary drive spindle (14), and the unlocking sleeve (44) being pushed axially from the front so far over that part of the bass body (17) which in situated on the tool side that It radially covers over the at least one connecting element (26).
2. Toolholder for a hand-held drill. particularly for a hammer drill, comprising a first tool scat (11), having clamp jaws (22), for tools having a round stem, and a second tool seat (12), functionally separate therefrom, for tools having a fluted stem, comprising a base body (17) having a reception opening (18) arranged in it, comprising at least one locking element (37), radially engageable in the reception opening (18), for locking the tools having a fluted stem, and c omp rising an unlocking sleeve (44) for unlocking tools inserted therein, characterized in that the toolholder (10) in provided with at least one connecting element (26) for the connection of the base body (17) to a rotationally drivable rotary drive spindle (14) of the hand-held drill, said connecting element being insertable partly into the base body (17) and partly into the rotary drive spindle (14), and the unlocking sleeve (44) being able to be pushed axially 1 i^ from the front so f a= over the base body (17) that it radially covers over the at least one connecting element which in in its inserted position.
3. Toolholder according to Claim 2, characterized In that the unlocking sleeve (44) In provided with catch means (60) which together with the base body (17), or with a component part incapable of axial translational movement relative thereto (for example supporting ring 30), form a stop (65) preventing axial displacement of the unlocking sleeve (44) forwards from the position securing the at least one connecting element (26).
4. Toolholder according to Claim 2 or 3, characterized In that in the case of the unlocking sleeve (44) the stop (65) in formed by means of at least one catch tongue is (61) which can be resiliently pressed radially outwards and which is provided with a catch surface (64) projecting radially inwards.
5. Toolholder according to Claim 2, characterized In that for the purpose of unlocking a tool having a fluted stem Inserted Into the second tool scat (12), the unlocking sleeve (44) can be moved axially backwards from the stop position (65) against the force of a closing spring (40).
6. Toolholder according to one of the preceding 25 claims # characterized In that the unlocking sleeve (44) In made of plastics material.
7. Toolholder particularly according to Claim 2, characterized in that the first tool scat (11) has a thrust bearing (28) whose bearing surfaces (71, 74) are formed in the one case on an adjusting ring (24) for the clamp jaws (22) and in the other case on a component part (for example supporting ring 30) connected in an axially fixed inanner to the base body (17), and which has rolling elements (29) arranged between the bearing surfaces (71, 74), the thrust bearing (28) having an outside diameter which in smaller than the Inside diameter (d) of the unlocking sleeve (44) in its narrowest portion (44a).
8. Toolholder according to Clad= 7, characterized In that the adjusting ring (24) in held by a spacer sleeve (31) in such a manner an to he axially inmovable in the forward direction, while on the space= sleeve (31) there in formed a sleeve-like extension (67) which extends axially over the adjusting ring (24) and which at least partly covers the rolling bodies (28) =adially on the outside.
9. Toolholde= according to Claim 7, characterized in that at least one of the bearing surfaces (71, 74) of the thrust bearing (28) has a circumferential annular shoulder (73) which at least partly covers the rolling bodies (29) radially on the outside.
10. Toolholder according to Claim 7, characterized in that the rolling bodies (29) are in the form of rolling balls and at least one of the two bearing surfaces (71, 74) of the thrust bearing (28) has a circumferential axial depression (72) in which the rolling balls (29) are arranged.

Z
11. A hand-held drill substantially as herein described with reference to the accompanying drawings.
12. A toolholder substantially as herein described with reference to Figures 1, 2 and 3, or Figure 4 or Figure 5 of the accompanying drawings.

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