DE2624775A1 - DEVICE FOR AUTOMATICALLY CHANGING THE JAWS OF THE CHUCK OF A MACHINE - Google Patents

Description

Dipl.-Ing. H. MITSCHERLICH D-8U00 MÖNCHEN 22

Dipi.-Ing. K. GUNSCHMANN Steinsdorfstrasse 10

Dr.rrnat. W. KÖRBER _ 3'_ ^ ⁽⁰⁸⁹⁾ * ²⁹⁶⁶⁸ *

Dipl.-Ing. J. SCHMIDT-EVERS 2624775

PATENT LAWYERS

June 2, 1976 SE / me

Gildemeister AG
4800 Bielefeld 1

At the Central station

Patent application

Device for the automatic changing of the clamping jaws of the chuck of a machine tool

The invention relates to a device for automatically changing the clamping jaws of the chuck of a machine tool, with a clamping jaw magazine and a transmission device to transfer the clamping jaws from the magazine to the chuck and vice versa.

The clamping jaws are changed in order to adapt the chuck to materials of different hardness or to different ones adapt the geometric shapes of the workpiece to be machined. The change takes place in conventional machine tools the jaws of the chuck still by hand. The jaws to be changed are removed from the chuck one after the other removed and the new jaws inserted one after the other in the chuck.

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The increasing automation of the production means has meanwhile also led to devices to automatically change the jaws of a chuck. For example, according to the DT-PS 2 104 904 an automatic changing device is known that works with two / one-part clamping jaws. Each clamping jaw consists from a radially adjustable base jaw remaining in the chuck and an exchangeable top jaw. The base jaws and top jaws have undercut grooves and projections on the sides facing one another which can be brought into engagement with one another for the purpose of connecting the two jaws. The ones needed to switch Sets of top jaws are held on pallets in a magazine in the direction of the chuck axis in series

are arranged one behind the other. The magazine can be moved parallel to the chuck axis. The transmission device consists of a swiveling double-armed gripper, by means of which pallets are removed from the magazine and can be changed can be driven against the chuck. The known device has the disadvantage that with her only the own two-part clamping jaws designed for this purpose can be exchanged. This means that the usual one-piece clamping jaws, as described, for example, in DT-PS 2 007 509, cannot be exchanged with such a device. In addition, the known device is quite complex and expensive.

The invention is based on the object of a simple device to automatically change the jaws of the chuck of a machine tool with which the usual one-piece clamping jaws can be exchanged.

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The object is achieved according to the invention in that the clamping jaws are arranged in the magazine in straight guides are that - when the chuck and magazine are in the change position relative to each other - the guide for at least one jaw of the chuck is aligned with the guide for at least one jaw of the magazine and that the transmission device has at least one transmission element movable in the direction of the aligned guides.

According to a first embodiment of the invention, the magazine can be designed as a ring magazine concentric with the chuck be designed in which the guides for the clamping jaws extend radially to the axis of the chuck.

The device is expediently designed so that one of the number of clamping jaws in the chuck has the same number of Guides for the clamping jaws in the ring magazine are aligned with the guides for the clamping jaws in the chuck. Bs would be It is now conceivable that the transmission device has only one transmission element, which successively to the points is performed where guides of the chuck are aligned with guides of the ring magazine in order to carry out the shift there. However, it is better if the transmission device is one of the number of clamping jaws in the chuck of the same number of transmission elements, each of which is associated with a pair of aligned guides. When the ring magazine For example, if it has three clamping jaws, the chuck and the ring magazine should be able to be positioned relative to one another in such a way that that the three guides of the chuck are simultaneously aligned with three guides of the ring magazine. With three transmission elements it would then be possible to exchange all three clamping jaws at the same time.

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It is conceivable that the ring magazine is stationary. To change the chuck would then have to be in the change position to be turned around. In addition, the transmission device would have to be movable, so that the transmission element or the Transmission elements are brought into a position in which they move the clamping jaws required for transmission can perform. However, it is simpler if the ring magazine can be rotated around the axis of the chuck and in certain, can be locked in rotational positions aligned with a basic position of the chuck. In this case, the Transmission device be stationary. The transmission element or the transmission elements can then also be aligned with the basic position of the chuck.

According to another embodiment of the invention, the magazine can be one that is perpendicular to the chuck axis Axis rotatable drum magazine or chain magazine, which is parallel to the last-mentioned axis on its circumference running guides for clamping jaws is provided.

But it is also possible that the drum or chain magazine next to the ring magazine concentrically surrounding the chuck is used. In this case, the arrangement is to be chosen so that a guide of the drum or chain magazine with a Guide of the ring magazine can be brought to flight, and that an additional transmission device for transmission of clamping jaws is provided between the two magazines, which one in the direction of the aligned guides of the two Has magazine movable transmission element.

According to an expedient development, the drum or chain magazine can be arranged so that - when the chuck around the ring magazine are in changing position relative to each other - a guide for the drum or chain magazine in flight with an aligned pair of guides

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the ring magazine and the chuck can be brought. If the displacement of the transmission element of the additional Transmission device is selected to be correspondingly long, a clamping jaw can be used with this transmission element be moved directly from the drum or chain magazine into the chuck and vice versa.

Another possibility for expanding the storage capacity for the chucks to be changed is that in the ring magazine at least two rows of annular rows arranged one behind the other in the axial direction of the chuck Guides for clamping jaws are provided, and that the ring magazine is axially displaceable. By axial displacement In this case, the selected row of clamping jaws can be brought into the changing position. To that The ring magazine can bring the rotatable ring magazine into the changing position in relation to a basic position of the chuck be connected to a rotary actuator. To avoid an additional drive for the axial displacement of the ring magazine purpose selection of the appropriate row of clamping jaws, another development of the invention can consist in that the ring magazine is provided with a relocating device, which - when the ring magazine is locked converts rotary energy transmitted from the rotary drive to the ring magazine into a displacement movement of the ring magazine. The ring magazine can consist of an axially fixed part and at least one guide for the clamping jaws containing! axially displaceable IS.1 exist, the rotary drive acts on the axially fixed part and the relocating device between the axially fixed part and the axially displaceable part is arranged.

709850/0251

A practical implementation of the transmission device can be that the transmission element of a Slidable rod is formed in the direction of alignment of the guides, which is attached to the clamping jaw to be displaced facing end having coupling means, and that on the circumferential side of each clamping jaw corresponding mating coupling means are provided. The coupling means on the rod can, for example, come from an undercut key head and the counter-coupling means be formed by an undercut keyhole, the rod being limited by a Angle is rotatable about its longitudinal axis, so that the undercuts of the keyhole and key head reach behind when the key head is inserted into the keyhole. Furthermore, a part of the rod can be threaded and another part may be provided with a non-circular profile, with a rotatable by a first drive on the thread, axial non-displaceable nut is seated. The part provided with the non-round profile can be in a with a corresponding Sitting non-circular hollow profile provided guide bushing, which can be rotated by a second drive through the limited angle.

Expediently, one uses one of the number of clamping jaws in the chuck with the same number of rods, which accordingly the change positions are arranged distributed over the circumference of the ring magazine. Anyone sitting on the bars can do this The outside nuts can be designed as a gearwheel, all gearwheel nuts with one being concentric to the chuck axis can mesh rotatably arranged first ring gear, which is connected to the first drive. So in this case all gear nuts on the first ring gear rotated by a single drive, so that the rod with their thread in the gear nut moved forward or backward.

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262477S

Similarly, it is possible to make the locking head of key and key hole when several rods with a single drive. This is achieved by providing each guide bushing on the rod with an external serration, whereby all of the guide bushes are connected directly or indirectly with their external serration to a ring rotatably arranged concentrically to the chuck axis and the ring is connected to the second drive will. When the second drive rotates the ring, the rotary movement is simultaneously transmitted to the guide bush, which then rotates through the aforementioned limited angle.

When using clamping jaws which are provided with a large number of toothed grooves on their backs, as is the case with the In the case of clamping jaws described in DT-PS 2 007 509, the clamping jaws can be resiliently mounted in the magazine

Latching elements are held in place, which / the tooth grooves engage.

In order to prevent chips from flying into the ring magazine when the workpiece is being machined in the chuck dirty, a cylindrical shielding wall can be arranged between the ring magazine and the chuck, which extends concentrically to the chuck axis. This shielding wall must have openings at least at the points where the jaws should be pushed through to switch between the chuck and the magazine. When the ring magazine is rotatable, the shielding wall can be fixed to the machine, with the openings on the The basic position of the chuck must be aligned.

A practical implementation of the idea presented above, the rotary energy transmitted from a rotary drive to the ring magazine when the ring magazine is locked in the direction of rotation in to implement an axial displacement movement can consist of

709850/0251

that on the axially fixed part of the ring magazine
a second toothed ring is rotatably mounted concentrically to the chuck axis, with which at least one gear wheel is in engagement. Each gear wheel can be connected non-rotatably to a screw spindle rotatably mounted on the axially fixed part of the ring magazine, v / obei each screw spindle with a corresponding threaded hole in the
axially displaceable part of the ring magazine in engagement
stands. The second toothed ring can then be connected to the rotary drive, while the axially fixed part of the ring magazine can be locked in certain rotary positions corresponding to the change positions by an indexing mechanism. In this practical implementation of the idea presented, the transfer device consists of the screw spindle belonging to the axially fixed part of the ring magazine and the threaded hole belonging to the axially displaceable part of the ring magazine. The indexing mechanism can be formed, for example, by a forward and backward movable indexing pin and matching indexing holes distributed over the circumference on the axially fixed part of the ring magazine.

An embodiment of the invention is based on the following of the drawings.

Show it:

1 shows a lathe with a ring magazine and a drum magazine;

FIG. 2 shows an enlarged illustration of the chuck and the ring magazine of the lathe shown in FIG. 1; FIG.

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Fig. 3 shows a section III-III through the chuck and the ring magazine in Fig. 2;

FIG. 4 is a simplified schematic side view of part of the lathe shown in FIG. 1, which the basic arrangement of the chuck, the ring magazine and the drum magazine can be seen.

The lathe shown in FIG. 1 has an inclined bed 2 with a tool turret 3. To a chuck 4 with three clamping jaws 5, a ring magazine 6 is arranged in which there are several sets of clamping jaws. The jaw change takes place by a three-part transmission device 7, which will be described in more detail later. Above that Ring magazine 6, a drum magazine 8 with an additional transfer device 9 is arranged.

According to FIG. 2, in the center of the chuck 4 there is a toothed wheel 10 that can be rotated separately with respect to the chuck 4, which meshes with a rack 11. The rack 11 is provided with inclined straight projections 12, which in Engage with correspondingly inclined straight grooves 13 on the back of a one-piece clamping jaw 5. The clamping jaw 5 can be displaced in undercut grooves 29 which form radial guides for the clamping jaw 5. if the gear wheel 10 is rotated relative to the chuck 4, the rack 11 moves tangentially the gear wheel 10, whereby the clamping jaw 5 is moved radially outwards or inwards. Jaws of this embodiment as well as the corresponding shifting mechanism are common today in machine tools and more precisely in the DT-PS 2 007 509.

709850/0251

The ring magazine 6 has a multiplicity of radial guides 31 for clamping jaws 5. For the sake of clarity is only part of the transmission device 7 is shown in FIG. This consists of a threaded 16 Rod with an undercut key head at the end

15 seated. In the outside of each clamping jaw 5 there is an undercut keyhole 14. The cross section of the keyhole 14 is adapted to the cross-sectional profile of the key head 15, so that the latter in the Keyhole can immerse. After one rotation of the rod

16 the key head 15 and that engage behind each other by 90 degrees Keyhole 14 so that the rod 16 can move the clamping jaw 5 radially for changing.

According to FIG. 3, a shaft 17, which carries the chuck 4, is mounted in a bearing of the housing of the machine 1. the Anchored in the chuck 4 clamping jaws 5 are provided with a T-profile, which in an undercut T-profile 29 is performed. On the shaft 17 sits a gear 18, which with a drive, not shown, for the Chuck 4 is connected.

In the ring magazine 6 two rows of guides 29 for clamping jaws 5 are provided. The guides are not recognizable; however, two clamping jaws 5 with their undercut T-profiles 21 are shown in the upper part of the ring magazine 6. The two clamping jaws 5 are held in the ring magazine by latching elements 48 which engage in the toothed grooves 13 on the back of the clamping baths 5. The locking elements 48 are pressed against the clamping jaws 5 by springs 42.

The ring magazine 6 is rotatable as a whole about the axis of the chuck 4. However, it consists of an axially fixed Part and an axially movable part. The axially fixed

709850/0251

The stationary part is supported by a roller bearing on a flange part 30 that is fixed to the machine. It consists of a molded part 97 and a ring 28 which are screwed together. A sleeve 26 is seated in the molded part 27 A toothed ring 38, which has an external toothing and an internal toothing, is mounted on the molded part 27 by means of a ball bearing having. The external toothing meshes with a gear 45, which sits on the drive shaft of a machine-fixed motor 46, which forms the rotary drive for the ring magazine 6. The internal teeth of the ring gear 38 meshes with a gear 40, which sits firmly on a spindle 42. The spindle 42 is rotatably mounted in the sleeve 26, but not axially displaceable.

The spindle 42 is provided with a threaded part 25 which is in sing engagement with the internal thread 44 of a threaded bushing 23. The threaded bushing 23 is screwed to a further molded part 22 by means of a screw 24. When the spindle 42 rotates, the threaded bushing 23 and the further molded part 22 are axially displaced. The threaded bushing forms accordingly 23 and the molded part 22 the axially displaceable part of the ring magazine 6. Located in this axially displaceable part the guides for the clamping jaws 5.

A thickened shoulder 33 of a stop bolt 34 is clamped between the ring 28 and the molded part 27. This one points a stop head 36 fastened with a screw 37 at its end. The stop head 36 corresponds with a stop surface 35 at the bottom of a recess with the molded part 22.

709850 / 02B1

The ring magazine 6 can be locked against rotation in certain rotational positions by an indexing mechanism v / earth. This consists of a machine-fixed block 49 in which an indexing pin 51 is mounted so as to be axially displaceable. The indexing pin 41 is connected to a piston 53, which is mounted in a cylinder space 52. The piston-cylinder arrangement the indexing mechanism can be hydraulically or pneumatically operated. The supply lines for the pneumatic or hydraulic operating means are omitted for the sake of simplicity. The molded part 27 is with a or a plurality of recesses 50 into which the indexing pin 51 can engage and the ring magazine 6 can lock.

The part of the transmission device 7 shown here consists of a rod 16, the bottom with a threaded part 16 A and above with a threadless part 16 B is provided. The threaded part 16A is guided in a nut 56, which is provided with teeth 61 on the outside. The nut 56 is rotatable, but not axially displaceable. The external toothing 61 of the cutter 56 meshes with a toothed ring 57, which is mounted on a machine-fixed ring part 55 via a ball bearing. The toothed ring 57 also meshes with a gear 59 which is seated on the drive shaft of a motor 60. The engine 60 is mounted on the machine. When the motor 60 rotates, the nut 56 is over the Toothed ring 57 rotated, whereby the rod 16 moves up or down.

The upper part 16B of the rod is unthreaded. However, it is provided with two ribs 72 which are inserted into corresponding grooves a guide bush 62 are mounted so as to be axially displaceable. The guide bush 62 is in turn rotatable in the machine-fixed Ring part 55 arranged, but not axially displaceable. The guide bush 62 has an external tooth 19th

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provided, v / which meshes with a gear 57, which also is in engagement with a drive pin 66 of a motor 65 fixed to the machine. With the motor 65 can alsG the guide bush 62 and thus also the rod 16 rotated, -will. The gear 57 sits on a shaft journal 68 which is connected to a ring 70 via a pivot lever 69 is. The guide bushings 62 for the two other rods are located at two other non-visible locations 16 connected to ring 70 in the same way. The swing levers 69 allow only a limited angular pivoting, since the ring 70 in both pivoting directions against the shaft journal 68 beats. This limited pivot angle defines the position in which the key head 15 in the Keyhole 14 can be inserted and on the other hand the position in which the keyhole and the key head are locked together.

Between the chuck 4 and the ring magazine 6 there is a cylindrical shielding wall 64, which is attached to the machine-fixed Flange part 30 is screwed on. The shielding wall 64 is at the three points where the clamping jaws are changed is to be provided with openings 71. In Figure 2, only one of these breakthroughs can be seen.

The changing device works as follows: First, the chuck 4 is in a defined basic position fixed. In this basic position, the guides 29 for the three clamping jaws are aligned with the openings 71 in the shielding wall 64. The motor 46 is then put into operation. Since the index pin 51 is initially withdrawn is, both the axially fixed part 27,28 and the axially displaceable part 22,23 are rotated. An axial one The axially displaceable part is not displaced.

7098S0 / 02S1

When the guides 31 of three positions not occupied by clamping jaws 5 in the ring magazine 6 with the guides 29 of the chuck 4 are aligned, there is a recess 50 in front of the indexing pin 51. The indexing pin 51 is then advanced into the recess 50 and locked the ring magazine 6 against rotation. At the same time, the motor 46 shut down. The motor 60 is then started, whereby the three rods 16 are advanced.

The clamping jaws 5 have previously been moved into the radially outermost position in which there is no engagement between the ribs 12 of the rack 11 and the grooves 13 in the clamping jaws 5 there is more (see Figure 2). After the key heads 15 have been inserted into the keyholes 14, the motor 60 stopped. Then the motor 65 is put into operation, whereby the rods 16 to the limited Angle can be rotated. This locks the key heads in the keyholes 14.

Then the motor 60 is put into operation again with the opposite direction of rotation, so that the three rods 16 with them The coupled clamping jaws 5 are retracted into the empty positions of the ring magazine 6.

It is now assumed that a set of clamping jaws the rear row of the ring magazine 6 is to be retracted into the chuck 4. After the indexing pin 51 is withdrawn has been, the motor 46 is now put into operation again. When the three jaws to be changed lie in a plane with the empty guides 29 of the chuck, the indexing pin 51 is back in the corresponding Recess 50 advanced. As a result, the ring magazine 6 is locked in this rotational position. The motor 46 is now, however not stopped, but continues to act on the toothed ring. This rotates the spindle 42, whereby the axially twisted

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slidable part 22.23 of the ring magazine moves to the right. The shifting movement is activated by switching off the The motor stops when the stop head 36 hits the stop surface 35. Now the three can change positions The clamping jaws 5 located in the back row are pushed into the empty guides 29 of the chuck 4 will. This is done in exactly the opposite way to the previously described pulling out of the clamping jaws from the chuck 4. The reference number 20 in FIG. 3 denotes the storage cavity for the clamping jaws 5.

From FIG. 4 it can be seen how the drum magazine 8 is arranged in relation to the ring magazine 6. The drum magazine 8 sits on a rotary drive 75 and is provided with guides 58 for the clamping jaws 5. The one on the drum magazine 8 arranged transmission device is provided with an extendable rod 76, which has a key head at its end 77 has. As described above, this can be inserted into the keyhole of the relevant clamping jaw to be changed retracted and locked there. To bridge the space required by the rotary drive 75 An intermediate guide 74 is arranged between the drum magazine 8 and the ring magazine 6. In the machine-fixed part 55 of the ring magazine 6, another guide 73 is provided. It is essential that a guide 58 of the Drum magazine 8 is aligned with a guide 31 in the ring magazine 6 and a guide 29 in the chuck 4, so that a clamping jaw 5 is moved in or out of the chuck 4 directly from the drum magazine 8 via the guides 74, 73, 29 this can be pulled out. The drum magazine only needs to be provided if the capacity of the ring magazine not enough.

7O9850 / 0251

Claims (22)

Claim 1) Device for automatic changing of the clamping jaws of the chuck of a machine tool, with a clamping jaw rack and a transfer device for transferring the clamping jaws from the magazine into the chuck and vice versa, characterized in that the clamping jaws (5) are arranged in straight guides (31,58) in the magazine (6,8) so that - when the chuck (4) and Magazines (6,8) are in the changing position relative to one another - the guide (29) for at least one clamping jaw (5) of the chuck (4) is aligned with the guide (31,53) for at least one clamping jaw (5) of the magazine (6,3), and that the transmission device (7,9) at least one in the direction of the aligned guides (22,31,53) movable having transmission element (16,76). 2) Device according to claim 1, characterized in that the magazine as a to the chuck (4) concentric Ring magazine (6) is formed in which the guides (31) for the clamping jaws (5) are radial to the axis of the chuck (4) course ... 3) Device according to claim 2, characterized in that one of the number of clamping jaws (5) in the chuck (4) the same number of guides (31) for the clamping jaws (5) in the ring magazine (6) align with the guides (29) of the clamping jaws (5) in the chuck (4). 4) Sinrichbung according to claim 3, characterized in that the transmission device (7) is one of the number of The same number of clamping jaws (5) in the chuck (4) 709850/0251 of transmission elements (16), each of which is assigned a pair of aligned guides (29,31) 5) Execution according to one of claims 2 to 4, characterized characterized in that the ring magazine (β) around the axis of the Chuck (4) is rotatable and can be locked in certain rotational positions. 6). Device according to claim 1, characterized in that the Kagazin around a perpendicular to the chuck axis standing axis rotating drum magazine (8) or chain magazine is that on its circumference with parallel to the last-mentioned axis extending guides (58) for the Jaws (5) is provided. 7) Device according to one of claims 2 to 5, and claim 6, characterized in that the drum or chain magazine close to the chuck (4) is arranged concentrically surrounding the ring magazine (6) so that a guide (53) the Drum or Kettsnmagazins (8) can be brought into alignment with a guide (31) of the ring magazine (6), and that an additional transmission device (9) is provided for transferring clamping jaws (5) between the two magazines (6, 8) which has a transmission element (76) which can be moved in the direction of the aligned guides (31,5-3) of the two magazines (6,8). 8) Device according to claim 7, characterized in that the drum or chain magazine (8) is arranged so that - When the chuck (4) and the ring magazine (6) are in "iiechselposition" relative to one another - a guide (58) of the Drum or chain magazine in alignment with an aligned pair of guides (29,31) of the ring magazine and the The chuck (4) can be brought to earth. 709850/0251 2824775 9) Device according to claim 7 and 8, characterized in that the transmission element of the additional Transmission device (9) is designed so that with it a clamping jaw (5) directly from the drum or i'sttenmagazin (8) in the chuck (4) and vice versa is movable. 10) Device according to one of claims 2 to 9, characterized in that at least two in the ring magazine (6) Rows of annular guides (31) arranged one behind the other in the axial direction of the chuck (4) for clamping jaws (5) are provided, and that the ring magazine (6) is axially displaceable. 11) Device according to claim 5 and 10, characterized in that the ring magazine (6) with a rotary drive (46) is connected and has a relocating device which - when the ring magazine (6) is locked - the Rotary energy transferred from the rotary drive (46) to the ring magazine (6) in a displacement movement of the ring magazine (6) implements. 12) Device according to claim 11, characterized in that the total rotatable ring magazine (6) consists of one axially fixed part (26,27,28) and at least one containing the guides (31) for the clamping jaws (5) axially displaceable part (22,23) consists that the rotary drive (46) on the axially fixed part (26,27,28) acts and that the transfer device between the axially fixed part (26,27,28) and the axially displaceable Part (22,23) is arranged. 708850/0251 -yr- 13) Device according to one of the preceding claims, characterized in that the transmission element (16) is formed by a in the direction of escape of the guides (22,31) displaceable rod, which is to be displaced on its Clamping jaw (5) facing the end has coupling means, and that on the circumferential side of each clamping jaw (5) appropriate counter-coupling means are provided. 14) Device according to claim 13 »characterized in that the coupling means on the rod (16) are formed by an undercut key head (15) and the mating coupling means are formed by an undercut keyhole (14), and that the rod (16) is at a limited angle is rotatable about its longitudinal axis, so that the undercuts of the keyhole (14) and key head (15) engage behind when the key head (15) is inserted into the keyhole (14). 15) Device according to claim 14, characterized in that one part (16A) of the rod (16) is threaded and another Part (16b) is provided with a non-circular cross-sectional profile that on the thread one of one first drive (60) rotatable, axially non-displaceable nut (56) sits that the one with the non-circular cross-sectional profile provided part (16B) in one provided with a corresponding non-circular hollow profile Guide bushing (62) sits, and that de guide bushing (62) from a second drive (65) to the limited angle is rotatable. 709850/0251 16) Device according to claim 4 and 15, characterized in that one of the number of clamping jaws (5) in the chuck (4) the same number of rods (16) are arranged distributed over the circumference of the ring magazine (6) in accordance with the change positions each of the nuts (56) seated on the rods (16) is designed on the outside as a gearwheel (61) so that all the gearwheel nuts (56,61) mesh with an erete toothed ring (57) rotatably arranged concentrically to the chuck axis, and that the first toothed ring (57) is connected to the first drive (60). 17) Device according to claim 4 and one of claims 13 to 16, characterized in that one of the number of Clamping jaws (5) in the chuck (4) the same number of rods (16) corresponding to the change positions over your circumference of the ring magazine (6) are arranged distributed so that each guide bushing (62) seated on the rod (16) is provided with an external toothing (19) that all guide bushes (62) with their external toothing (19) with a ring rotatably arranged concentrically to the chuck axis (70) are connected directly or indirectly, and that the ring (70) is connected to the second drive (65). 18) Device according to one of the preceding claims, wherein the clamping jaws on their rear sides with a plurality are provided by toothed grooves, characterized in that the clamping jaws (5) in the magazine (6,8) by resilient mounted locking elements (48) are held in place, which engage in the toothed grooves (47). 19) Device according to one of claims 2 to 18, characterized marked that between the ring magazine (6) and the chuck (4) a cylindrical shielding wall (64) extends which is concentric to the chuck axis is arranged, and that the shielding wall (64) on the stalls openings (71) on v / eist where clamping jaws zua change 709850/0251 2524775 -f should be pushed through between the chuck (4) and the magazine (6,8). 20) Device according to claim 19, characterized in that the shielding wall (64) is fixedly arranged. 21) Device according to claim 12, characterized in that on the axially fixed part (26,27,28) of the ring magazine (6) a second toothed ring (38) is rotatably mounted concentrically to the chuck axis that with the second Toothed ring (38) at least one gear (40) is in engagement that each gear (40) rotatably with one on the axially fixed part (26,27,28) of the ring magazine (6) rotatably mounted screw spindle (42) is connected that each screw spindle (42) with a corresponding threaded hole (44) in the axially displaceable part (22,23) of the ring magazine (6) is in engagement that the second toothed ring (38) is connected to the rotary drive (46) is, and that the axially fixed part (26,27 »28) of the Ring magazine (6) by an indexing mechanism (49-53) in certain rotational positions corresponding to the change positions is lockable. 22) Device according to claim 20, characterized in that the indexing mechanism (49-53) from a front and indexing pin (51), which can be moved back, and index holes (50) matching the circumference on the axially fixed one Part (26,27,28) of the ring magazine (6) is formed. Patent attorney 709850 / 02St