Holding chuck for machines for the production of glass containers

Description

Field of invention

[0001] The present invention relates generally to the manufacture of glass containers, in particular for use as primary packaging for pharmaceutical active ingredients, for example as glass vials, cartridges or syringe bodies, and in particular relates to a holding chuck for machines that can be loaded with glass tubes for the manufacture of such glass containers. Background of the invention

[0002] Chucks for tubes or cylindrically symmetrical workpieces are well known in the art. However, chucks for glass tubes are subject to special requirements, as glass tubes can only withstand low radial clamping forces and break if excessive forces are applied. Chucks in conventional hot forming machines for the production of vials from tubes also require that the chuck be able to open and close very quickly and that, after clamping, the chuck reliably clamps the glass tube without applying any external force to the chuck.

[0003] A holding chuck is known from EP 0 469 297 A2 of the applicant and comprises a central loading channel for the glass tubes, several adjustable clamping jaws at the lower end of the loading channel and distributed around its opening, the distance of which to the centerline of the loading channel is adjustable, an actuating element for adjusting the clamping jaws together, a gear that couples the adjustable clamping jaws to the actuating element, and guides to guide an adjustment movement of the clamping jaws perpendicularly, radially inward to the centerline of the loading channel. Due to this design, the clamping jaws are free from longitudinal movement when gripping the glass tubes and can thus grip the glass tube without longitudinal displacement. This enables a secure and centered gripping of a glass tube.

[0004] For this purpose, a positive guidance system is provided, formed by a cam guide in a pressure sleeve and a driver guided in the cam guide, which is arranged on each of the clamping jaws. The positive guidance runs at a constant angle with respect to the longitudinal axis of the feed channel. The clamping force acting on glass tubes with different outer diameters is therefore always constant.

[0005] Another holding chuck is disclosed in DE 10 2008 058 211 A1. In this holding chuck, the clamping jaws are guided along guides that extend inclined towards the center line and towards the opening at the lower end of the feed channel. As a result, the gripping of glass tubes is not free from longitudinal displacement, which can adversely affect the achievable positioning accuracy of the glass tubes.

[0006] Another holding chuck used for processing glass tubes at high temperatures is known, for example, from CN 103073177 A. However, this chuck does not have a central feeding channel. Instead, it features two clamping jaws with V-grooves, which are adjusted by an eccentric actuating element. This arrangement is not suitable for producing glass vials, cartridges, or syringe bodies in machines with high cycle rates that require rapid opening and closing of the clamping jaws.

[0007] JP 2001019451 A1 discloses a device for clamping glass rods for use in a redrawing process, whereby the glass rod is not subjected to bending during clamping. In this process, the glass rod is clamped successively above and below an oven for reheating. To prevent a change in position during the second clamping, the clamping jaws are initially moved to their stop without exerting significant force. Subsequently, in a second phase, toggle lever elements are moved with considerable force. However, the toggle lever elements are not used to translate a movement in the sense of a coupling element.

[0008] FR 689 782 A discloses a holding device for cup-shaped objects. The holding device comprises two jaws that can clamp part of the cup-shaped object, with the cup-shaped object abutting a rod of the holding device. The holding device is not suitable for glass tubes, as the holding device itself would obstruct long cylindrical objects.

[0009] In view of the ever-increasing demands on the product quality of glass containers for use as primary packaging for pharmaceutical active ingredients, there is therefore a need for further improvement. Summary of the invention

[0010] A general object of the present invention is to provide an improved holding chuck for machines for the manufacture of glass containers that can be loaded with glass tubes, with which glass tubes can be reliably held in a simple manner over a large range of diameters.

[0011] This problem is solved by a holding chuck according to claim 1. Further advantageous embodiments are the subject of the dependent claims.

[0012] According to the present invention, a holding chuck for machines that can be loaded with glass tubes for the production of glass containers, in particular for the production of glass vials, cartridges or syringe bodies, is provided, comprising a central loading channel for the glass tubes, several adjustable clamping jaws at the lower end of the loading channel, which are arranged distributed around its opening and whose distance to the center line of the loading channel is adjustable, an actuating element for adjusting the clamping jaws, a coupling element or gear unit that couples the adjustable clamping jaws to the actuating element, and guides to guide an adjustment movement of the clamping jaws perpendicular to the center line of the loading channel and exactly radially inwards.

[0013] According to the invention, the coupling element or gear unit comprises levers, or is formed by levers, each pivotally connected to the actuating element and an associated clamping jaw. The actuating element is elastically pre-tensioned against a base body of the chuck by means of a spring. The coupling element is designed such that the ratio between a radially acting clamping force of the clamping jaws and an elastic restoring force of the spring is continuously reduced as the opening width of the clamping jaws decreases. The levers and their leg lengths provide parameters with which a characteristic curve of the clamping force of the chuck can be suitably adjusted for a wide range of glass tube diameters. Simultaneously, the chuck can be used for a wide range of different glass tube diameters without changing the clamping jaws.A set of jaws can in particular cover a diameter range of glass tubes suitable for the manufacture of all commercially available primary packaging materials for pharmaceutical active ingredients, especially for a range of outer diameters between 6 mm and 32 mm.

[0014] By adjusting the holding forces over a large tube diameter range, glass tube breakage, damage, and slippage can be reliably prevented. Because the clamping jaws are adjusted precisely radially inwards without axial offset, no axial displacement of the glass tube occurs when the holding chuck is opened and closed. Therefore, according to the invention, the holding chuck can also be opened and closed very quickly.

[0015] According to the invention, the actuating element is elastically pre-tensioned against a base body of the chuck by means of a spring, wherein the coupling element or gear continuously reduces the ratio between a radially acting clamping force of the clamping jaws and an elastic restoring force of the spring as the opening width of the clamping jaws decreases. This enables a particularly advantageous characteristic curve of the chuck, because glass tubes with small outer diameters are typically characterized by lower mechanical stability and fracture resistance, which requires relatively low clamping forces, while glass tubes with larger outer diameters are also characterized by greater mechanical stability and fracture resistance, which allows for higher clamping forces, which are also necessary due to their greater weight.A holding chuck according to the present invention can be easily adapted to these conditions by appropriately designing a toggle lever formed by the levers. The parameters available for this purpose include, in particular, the leg lengths of the levers, the angle enclosed by the legs, and the position of the levers' axes of rotation.

[0016] The coupling element acts as a transmission to convert an adjusting force of the actuating element, preferably directed parallel to the longitudinal axis of the feed channel, into a suitably translated and precisely radially inward-directed adjusting force of all clamping jaws, which can be adjusted radially inward synchronously. The translation is preferably set such that the prevailing clamping forces are comparatively small for relatively small glass tube diameters and increase continuously for larger glass tube diameters, with the characteristic curve of the adjusting force preferably having no discontinuities or reversal points.

[0017] According to another embodiment, the spring is arranged concentrically around the base body of the chuck and supported against flange-like sections of the actuating element and the base body of the chuck. This allows for a particularly space-saving design of the chuck with relatively few functional components. The spring force can be adjusted by changing the distance between the two flange-like sections, for example by turning a nut or adjusting the flange-like section on the base body of the chuck.

[0018] According to a further embodiment, the levers are designed as angled levers with a first leg and a second leg, wherein the first leg is pivotally connected to the actuating element and the second leg is pivotally connected to an associated clamping jaw. This toggle lever principle allows for a particularly simple adjustment of the clamping forces and adjustment ranges to the outer diameter of the glass tubes over a relatively large range.

[0019] According to a further embodiment, the first legs extend essentially perpendicular to the center line when the clamping jaws are adjusted radially inward almost to the center line, while the first legs extend at an acute angle to the lower end of the feed channel when the clamping jaws are maximally open. At the end of the clamping jaw adjustment movement, i.e., when the clamping jaws are adjusted relatively close to the center line of the actuating channel, the clamping jaws are thus adjusted by a comparatively small travel when the angled lever is moved. This corresponds to a range with relatively small glass tube diameters.For relatively large glass tube diameters, the clamping jaws are adjusted by a comparatively large adjustment range when the angled lever is adjusted, which corresponds to correspondingly larger clamping forces, which are possible due to the higher mechanical stability and break resistance of glass tubes with larger outer diameters.

[0020] An advantageously simple design is possible according to a further embodiment if a bolt is provided at the front end of the first legs, which is guided slidably in a groove on the actuating element, and if a bolt is provided at the front end of the second legs, which is guided slidably in a groove of the associated clamping jaw.

[0021] According to a further embodiment, the grooves on the actuating element extend perpendicular to the center line of the actuating element. For larger opening widths of the clamping jaws, it is preferred if the first leg of the angled lever extends at an acute angle to the center line of the feed channel and in the direction of the opening at the lower end of the feed channel, because relatively large adjustment ranges are then possible when the actuating element is adjusted. For smaller opening widths of the clamping jaws, however, it is preferred if the first leg of the angled lever extends essentially horizontally, perpendicular to the center line of the feed channel, because only relatively small adjustment ranges are then possible when the actuating element is adjusted.

[0022] According to a further embodiment, the groove of the associated clamping jaw extends parallel to the center line of the actuating element. The sliding movement of the sliding bolt in this groove therefore causes only minimal tilting forces when adjusting the respective clamping jaw.

[0023] According to a further embodiment, the grooves on the actuating element are formed in guide arms that project radially outwards from the actuating element, whereby the position of the sliding bolt at the front end of the first leg of the angled lever can be advantageously moved radially outwards in a simple manner.

[0024] According to a further embodiment, the pivot axes of the levers are mounted on a guide block that is fixedly located at the lower end of the actuating element, in particular at the lower end of a rotatably mounted shaft that encloses or directly forms the feed channel. The distance of the pivot axes of the levers to the centerline of the feed channel thus does not change when the chuck is adjusted, which enables even more precise clamping of the glass tubes.

[0025] According to a further embodiment, a section of the actuating element containing the grooves in which the bolts at the front ends of the first legs of the levers are slidably guided is designed as a rotationally symmetrical body. The aforementioned grooves are formed in this body by machining the actuating element through turning. This allows for even more precise adherence to tolerances in this area, which is critical for adjusting the levers, thus enabling even more precise adjustment of the levers overall. It has been shown that the tolerances for machining such grooves by turning the actuating element can be automatically and with high accuracy, ensuring precise adjustment of all levers.

[0026] According to a further embodiment, the guides are designed as cylindrical or polygonal guide sleeves at the lower end of the guide block, wherein the clamping jaws are cylindrical or polygonal and corresponding to the cylindrical or polygonal guide sleeves, and are slidably guided within the cylindrical or polygonal guide sleeves. Cylindrical cross-sectional shapes are particularly preferred, as they can be manufactured cost-effectively and precisely by simple machining by turning a workpiece.

[0027] According to a further embodiment, which is expressly also to be regarded as an independent aspect of the invention and can be claimed independently, each chuck is directly associated with a drive motor, which is arranged directly on a shaft enclosing the feed channel in order to rotate the shaft with the chuck provided thereon. Thus, the chucks of a hot forming machine can be accelerated even more rapidly, which, according to the invention, enables very high cycle rates of the hot forming machine. Figure overview

[0028] The invention will now be described in an exemplary manner with reference to the accompanying drawings, from which further features, advantages, and problems to be solved will become apparent. The drawings show: Fig. 1 is a schematic representation of a holding chuck according to the present invention, showing preferred lever ratios; Figs. 2a and 2 are a sectional view in the area of ​​the clamping jaws and a schematic representation of the holding chuck according to the Fig. 1 when clamping a glass tube with a comparatively small outer diameter; Figs. 2c and 2din show a sectional view in the area of ​​the clamping jaws and a schematic representation of the holding chuck according to the Fig. 1 in a position with a comparatively large opening width of the clamping jaws; Fig. 3 in a schematic longitudinal section a holding chuck according to the present invention; Figs. 4a and 4 in schematic longitudinal sections the lower part of the holding chuck according to the Fig. 3in a position with a comparatively large opening width of the clamping jaws and in a position with a comparatively small opening width of the clamping jaws; and Fig. 5 typical characteristic curves of a holding chuck according to the present invention for different spring preloads.

[0029] In the figures, identical reference symbols denote identical or essentially equivalent elements or groups of elements. Detailed description of preferred embodiments

[0030] First, the general structure of a holding chuck according to the invention is described using the following examples: Fig. 3 described.

[0031] In a glass processing machine (not shown), for example in a rotary table mount, the holding chuck 50 is arranged. The holding chuck 50 comprises a base body 51 that is rotationally symmetrical overall, in which a longitudinally extending feed channel 52 for the glass tube 9 to be held is formed. This feed channel extends to a guide block 2 in which clamping jaws 4 for frictionally holding the glass tube (not shown) are guided. A drive motor is provided at the upper end of the base body 51 to set the holding chuck into a rapid rotational movement about the longitudinal axis of the feed channel 52 for hot forming of a held glass tube. More precisely, the drive motor 57 is housed in a motor casing 56, which is arranged directly on the outside of the base body 51, in particular on a shaft.In a practical application, the motor housing 56 is attached directly to a rotary ring of a hot forming device (not shown) via a mounting flange 58 or the like. Bearings 59, 60 are provided between the drive motor 57 and the base body 51 or shaft, so that the base body 51 or the shaft is directly set into rotary motion by the drive motor 57. Due to the low moving masses, the rotary motion can be rapidly accelerated and decelerated, which, according to the invention, enables very high cycle rates of a hot forming device.

[0032] Above the guide block 20, which is fixedly located at the lower end of the feed channel 52 or the base body 51, an actuating element 1, which is rotationally symmetrical overall, is arranged and is adjustable on the base body 51 in the actuating direction B, parallel to a longitudinal axis or center line of the feed channel 52, as indicated by the double arrow.

[0033] As in the Figures 4a and 4bAs shown, the actuating element 1 comprises a cylindrical upper and lower sleeve 10, 11, between which a radially projecting flange 12 is formed. The lower end of the spring 54 is supported on this flange, while the other end is supported on a spring stop 53 on the base body 51 to elastically preload the actuating element 1 against the base body 51. The spring force of the spring 54 can be adjusted, if necessary, depending on the product, for example, by means of a nut and by axially adjusting the spring stop 53 on the base body 51. The guide block 20 is cylindrical overall.

[0034] At least two clamping jaws 4 are arranged at the lower end of the guide block 20 at uniform angular intervals from each other. Preferably, at least three clamping jaws 4 are provided in order to clamp the glass tube uniformly at at least three point-like areas.

[0035] The clamping jaws 4 are slidably mounted in correspondingly designed guide sleeves 21 at the lower end of the guide block. The guide sleeves 21 are aligned such that the clamping jaws 4 are moved radially inwards and towards the center line 55 of the feed channel. According to the invention, no axial offset occurs during the radial adjustment of the clamping jaws 4. The clamping jaws 4 are adjusted synchronously by actuating the actuating element 1. For uniform clamping of the glass tube, it is essential that all clamping jaws 4 are of the same length.

[0036] For precise guidance of the clamping jaws 4, these have a cylindrical cross-section and are guided in correspondingly shaped cylindrical guide sleeves 21 of the guide block 20. This has the advantage that the clamping jaws 4 can be manufactured precisely by machining, and the guide sleeves 21 can also be precisely drilled or milled. However, other cross-sectional shapes for the clamping jaws 4 are also possible, in particular polygonal cross-sectional shapes.

[0037] The guide sleeves 21 extend exactly horizontally, i.e., perpendicular to the center line 55 of the feed channel, so that the clamping jaws 4 are guided exactly horizontally, radially inwards, and without axial offset during adjustment, in order to hold the glass tube frictionally without longitudinal displacement. Due to the precisely radial inward guidance of the clamping jaws 4, no disruptive axial offset occurs when clamping a glass tube.

[0038] The clamping jaws 4 are articulated to the actuating element 1 via associated levers 3. More precisely, a sliding bolt 33 is provided at a front end of a first leg 30 of the lever 3, which is slidably mounted in a guide groove 14 formed in a guide arm 13 at the lower end of the actuating element 1. Furthermore, a sliding bolt 34 is provided at a front end of a second leg 31 of the lever 3, which is slidably guided in a guide groove 41 formed in the respective clamping jaw 4.

[0039] By applying an external force to the clamping ring flange 12 in the direction of spring 54, the preload force of spring 54 can be overcome. The actuating element 1 then slides upwards on the base body 51, simultaneously engaging the three levers 3. The levers 3 are connected to the guide block 20 via the sliding pins 34. The guide block 20 is, in turn, slidably guided within the actuating element 1. The levers 3 rotate around the guide block 20. This movement adjusts the pivot bearings and the clamping jaws 4, thereby changing the opening width of the clamping jaws 4.

[0040] To compensate for the difference in length between linear and rotary movements, the components (actuating element 1 and clamping jaws 4) are provided with guide grooves, which are expediently designed as elongated holes. The orientation of these guide grooves or elongated holes is determined by whether radial or axial movement components must be locked or allowed to move freely.

[0041] Preferably, the guide groove 14 in the guide arm 13 extends exactly in a horizontal direction, perpendicular to the center line 55 of the feeding channel. Furthermore, the guide groove 41 in the respective clamping jaw 4 preferably extends exactly vertically, parallel to the center line 55 of the feeding channel. However, other orientations of the guide grooves 14 and 41 are also possible in principle, because in any case the alignment of the guide sleeves 21 ensures an exactly horizontal adjustment movement of the clamping jaws 4. The [unclear text] Figures 4a and 4b However, the orientations of the guide grooves 14, 41 shown allow for a relatively force-saving adjustment of the clamping jaws 4.

[0042] The pivot axes 32 of the levers 3 are mounted in the guide block 20, which, due to its fixed arrangement at the lower end of the feed channel and the radially symmetrical forces prevailing there, always ensures that the pivot axes 32 are mounted at a constant distance from the center line 55 of the feed channel. The pivot axes 32 can be, as shown in the Fig. 3 shown, are stored in bores in the guide block 20.

[0043] For even more precise positioning of the levers 3 and their pivoting movement about the axes of rotation 32, it is preferred that the guide grooves 14 for guiding the sliding bolts 30 are formed by machining the actuating element 1. Machining the actuating element 1 ensures that all guide grooves can be manufactured with tight tolerances and that the sliding bolts 30 are guided radially inwards or outwards with absolute precision. The sliding bolts 30, 31 of the levers 3 can be designed as cylindrical locking bolts, which are secured in the corresponding guide grooves 14, 41 by means of retaining rings.

[0044] How to get the Figures 4a and 4bAs can be seen, the lever 3 is designed as an angled lever, wherein the two legs 30, 31 of the lever 3 enclose an angle with each other which is expediently in the range between 45° and 135° and preferably in the range between 60° and 120° and even more preferably is 90° or deviates from 90° by only a few degrees.

[0045] The lever 3 enables an advantageous translation of the adjustment of the actuating element 1 in the actuation direction B, according to the toggle lever principle, into an adjustment of the clamping jaws 4 in the horizontal direction, perpendicular to the center line of the feed channel. The special feature of the toggle lever principle lies in the fact that the transmission ratio of applied force to resulting force, or of primary stroke to secondary stroke, can continuously shift during movement. According to the invention, this allows the clamping jaws 4 to initially be moved quickly and with a relatively large stroke towards the glass tube during their adjustment; to be moved towards the glass tube with medium speed and medium stroke in a middle range; and finally, for small glass tube diameters, to be moved towards the glass tube with low speed and a very small stroke.

[0046] This corresponds to the prevailing clamping forces in the aforementioned ranges: for relatively large glass tube outer diameters, the clamping force generated by the clamping jaws 4 is comparatively large; for medium-sized glass tube outer diameters, the clamping force generated by the clamping jaws 4 is medium; and for small glass tube outer diameters, the clamping force generated by the clamping jaws 4 is comparatively small. The prevailing clamping forces can thus be optimally adapted to the stability of glass tubes over a wide diameter range, since glass tubes with relatively large diameters are characterized by higher stability, whereas glass tubes with relatively small diameters are characterized by lower stability.

[0047] How to get the Figures 4a and 4b As can be seen, lever 3 is located in the area of ​​relatively large glass tube diameters ( Fig. 4a) such that the first leg 30 extends at an acute angle towards the lower end of the feed channel, while the lever 3 in the area of ​​relatively small glass tube diameters ( Fig. 4b ) such that the first leg 30 extends essentially perpendicular to the center line 55. At the same time, the sliding bolt 23 is located at the front end of the first leg 30 in the area of ​​relatively large glass tube diameters ( Fig. 4a ) relatively far inside the guide groove 14 and the sliding bolt 34 at the front end of the second leg 31 in the upper or middle area of ​​the guide groove 41 in the clamping jaw 4, while the sliding bolt 23 at the front end of the first leg 30 is located in the area of ​​relatively small glass tube diameters ( Fig. 4bThe guide groove 14 and the sliding pin 34 are located relatively far out in the guide groove 14 and at the front end of the second leg 31 in the lower part of the guide groove 41 in the clamping jaw 4. In this way, the chuck can accommodate a very wide range of glass tube diameters. Ideally, the lever ratios are chosen such that all common glass tube diameters for the production of primary packaging for pharmaceutical active ingredients, in particular glass vials, cartridges or syringe bodies, are covered, especially a range between approximately 6 mm and 32 mm.

[0048] Fig. 1 This schematically summarizes preferred leverage ratios of a holding chuck according to the present invention. The following parameters are specified: k: spring constant s 0 : spring preload s 1 : spring travel a 1 : leg length of the first leg 30 a 2 : leg length of the second leg 31

[0049] The following applies to the dependence of the clamping force on the spring travel s: F N s = a 1 a 2 × cos 2 α × F Feder = a 1 a 2 × cos 2 sin − 1 s a 1 × k × s

[0050] This dependency can be simplified for the preferred case of equal leg lengths a 1 = a 2: <menclose notation="box"> F N s 1 = cos 2 sin − 1 s 1 a 1 × k × s 0 + s 1 f ü r a 1 = a 2 < / menclose>

[0051] Furthermore, the following applies to the preferred case of equal leg lengths: <menclose notation="box"> r A s 1 = 6.5 + s 1 f ü r a 1 = a 2 d A s 1 = 13 + 2 × s 1 f ü r a 1 = a 2 < / menclose>

[0052] By appropriately selecting the leg lengths, the force ratios can be suitably adjusted for the different ranges of glass tube diameters according to the invention.

[0053] The Figures 2a to 2d For a preferred design of the toggle lever, the angular relationships and geometry during clamping are summarized for relatively small and relatively large opening widths of the clamping jaws.

[0054] The Fig. 5The figure shows typical characteristic curves of a holding chuck according to the present invention for different spring preloads. It can be seen that the prevailing clamping forces are comparatively small for relatively small glass tube diameters and increase continuously to larger glass tube diameters, preferably without any discontinuities or reversal points in the characteristic curves.

[0055] As will be readily apparent to the person skilled in the art, the retaining chuck according to the present invention can also be used in a similar manner for the manufacture of other types of glass containers produced by hot forming from glass tubes, in particular generally for the manufacture of glass packaging materials, even with larger dimensions than are usual for storing pharmaceutical active ingredients. Reference symbol list

[0056] 1 Actuating element 2 Guide block 3 Angle lever 4 Clamping jaw 9 Glass tube 10 Upper sleeve 11 Lower sleeve 12 Flange 13 Guide arm 14 Guide groove 15 Opening 20 Guide block 21 Guide sleeve 25 fuse slot 30 first lever arm 31 second lever arm 32 axis of rotation 33 first sliding bolt 34 second sliding bolt 40 Clamping jaw cylinder 41 Guide groove 50 Chuck 51 Base body 52 Feed channel 53 Spring stop 54 Tension spring 55 Center line 56 Motor housing 57 Drive motor 58 Mounting flange 59 Bearing 60 Bearing Direction of operation

Claims

1. A retention chuck for glass pipes for machines which can be supplied with glass pipes for producing glass containers, having a central supply channel (52) for the glass pipes, a plurality of adjustable clamping jaws (4) which are arranged at the lower end of the supply channel and distributed around the opening thereof, wherein the spacing thereof from the center line of the supply channel is adjustable, an actuation element (1) for joint adjustment of the clamping jaws, a coupling element which couples the adjustable clamping jaws (4) to the actuation element (1), and guides (21) in order to guide an adjustment movement of the clamping jaws perpendicularly, radially inwardly relative to the center line of the supply channel (52), characterized in that the coupling element comprises levers (3) which are each connected in an articulated manner to the actuation element (1) and an associated clamping jaw (4), wherein the actuation element (1) is resiliently pretensioned by means of a spring (54) against a base member (51) of the retention chuck (50), wherein the coupling element is configured in such a manner that a ratio between a radially active clamping force of the clamping jaws (4) and a resilient restoring force of the spring (54) is continuously decreased as the opening width of the clamping jaws decreases.

2. The retention chuck as claimed in claim 1, wherein the spring (54) is arranged concentrically around the base member of the retention chuck (50) and is supported against flange-like portions (12, 53) of the actuation element (1) and of the base member (51) of the retention chuck (50).

3. The retention chuck as claimed in one of the preceding claims, wherein the levers are constructed as angled levers (3) having a first leg (30) and a second leg (31), wherein the first leg (30) is connected to the actuation element (1) in an articulated manner and the second leg (31) is connected to an associated clamping jaw (4) in an articulated manner.

4. The retention chuck as claimed in claim 3, wherein the first legs (30) extend perpendicularly to the center line when the clamping jaws (4) are adjusted radially inward almost as far as the center line, and wherein the first legs (30) extend in an inclined manner at an acute angle with respect to the lower end of the supply channel when the clamping jaws (4) are opened to the maximum extent.

5. The clamping chuck as claimed in claim 3 or 4, wherein at the front end of the first legs (30) there is provided in each case a pin (33) which is slidingly movably guided in a groove (14) at the actuation element (1) and wherein at the front end of the second legs (31) there is provided in each case a pin (34) which is slidingly movably guided in a groove (41) of the associated clamping jaw (4).

6. The retention chuck as claimed in claim 5, wherein the grooves (14) at the actuation element (1) extend perpendicularly to the center line of the actuation element and wherein the grooves (41) of the associated clamping jaw (4) extend parallel to the center line of the actuation element.

7. The retention chuck as claimed in claim 5 or claim 6, wherein the grooves (14) are formed at the actuation element (1) in guiding arms (13) which protrude radially outward from the actuation element.

8. The retention groove as claimed in claim 6 or claim 7, wherein a portion (13) of the actuation element (1) in which the grooves (14) are formed is constructed as a rotationally symmetrical member in which by turning by a machining processing operation the grooves (14) are formed, in which the pins (33) are slidingly movably guided at the front ends of the first legs (30).

9. The retention chuck as claimed in one of the preceding claims, wherein rotation axles (32) of the levers (3) are supported on a guiding block (20) which is provided so as to be fixed to the lower end of the supply channel (52).

10. The retention chuck as claimed in claim 9, wherein the guides (21) are formed at the lower end of the guiding block (20).

11. The retention chuck as claimed in one of the preceding claims, wherein the guides are constructed as cylindrical or polygonal guiding sleeves (21) and wherein the clamping jaws (4) are constructed in a cylindrical or polygonal manner and so as to correspond to the cylindrical or polygonal guiding sleeves which are slidingly movably guided in the cylindrical or polygonal guiding sleeves.

12. The retention chuck as claimed in one of the preceding claims, further comprising a drive motor (57), which is arranged directly on a shaft which encloses the supply channel (52) in order to rotate the shaft with the retention chuck provided thereon.