Clamping jaw system

Abstract

Clamping jaw system for a machine spindle of a machine tool for clamping workpieces with a chuck (10), comprising at least two base jaws (18), characterized in that at least two different top jaws (22, 30) are arranged on the chuck (10), wherein one top jaw is designed as a pointedly toothed jaw (22) and another top jaw is designed as a quick-change jaw (30), wherein a straight toothing (16) or helical toothing is formed on the base jaw (18), which serves to tooth a corresponding toothing (34) on the quick-change jaw (30) and the base jaw (18) is moved in the direction of the quick-change jaw (30) by the use of an assembly tool (46) and the toothing (16) of the base jaw (18) toothing with the toothing (34) of the quick-change jaw (30).

Description

[0001] The invention relates to a clamping jaw system according to the preamble of the main claim. State of the art

[0002] Clamping jaws for chucks are known to have an interchangeable jaw and a carrier jaw, with the carrier jaw having a seat for accommodating an interchangeable jaw. Such clamping jaws are often used for rotary jaw chucks on lathes. These jaws are usually adjusted via spindles. Rotary jaw chucks are used to clamp workpieces that are to be machined, for example, by drilling, milling, turning, etc.

[0003] Chucks with multiple clamping jaws, each consisting of a base jaw and a top jaw, are known. In these chucks, the top jaw is interchangeably arranged in a recess formed in the end face of the base jaw and rests against a stop surface under the load of centrifugal and clamping forces. In these chucks, the top jaws are attached to the base jaws using screws, with at least one, but usually two, screws provided for each top jaw. Attachment can be achieved either directly, by the screws connecting the top jaw to the base jaw, or indirectly, by clamping the top jaw in an undercut groove in the base jaw.

[0004] The disadvantage of these jaw attachments is that to replace the top jaws, at least one, but usually two, screws per clamping jaw must be loosened or even removed and then screwed back in together with the new top jaw. This results in significant retooling work when changing the jaws. Especially on machine tools with multiple spindles, such as multi-spindle machines, this results in machine downtime, which hinders efficient production processes.

[0005] For this reason, when designing clamping jaws for chucks, the clamping jaws are typically designed to minimize the time required to adapt the chuck to different dimensions of the workpiece to be clamped, while ensuring a secure connection between the clamping jaws and the chuck. Particularly for chucks on lathes, the secure connection between the clamping jaw and the chuck is crucial, as the clamping jaws are subject to large forces, such as centrifugal forces. A poor connection between the clamping jaws and the chuck can have detrimental consequences.

[0006] To meet the increasingly frequent demand for flexible component production, the ability to convert to different workpieces within a single machine is becoming increasingly important. Setup costs also represent a significant component of the manufacturing costs of the respective workpieces. Therefore, setup times are the decisive factor for achieving a reasonable manufacturing price, particularly in the small-batch turned part sector. Of particular note here are the times for changing tools, clamping devices, and jaws, which have a substantial impact on setup times. For these reasons, the lathe chuck industry has been working with quick-jaw change systems for many years to simplify and accelerate changeovers to different workpieces.

[0007] Against this backdrop, clamping jaws were developed that consist of two components: a carrier jaw firmly screwed to the chuck and an interchangeable jaw mounted on the carrier jaw, which can be changed relatively quickly. However, the disadvantage of quick-jaw-change systems is that they often result in losses in repeatability during production. Furthermore, quick-jaw-change systems only reduce setup times by a relatively small amount. A significantly greater cost-saving potential results from reducing changeover times for the entire chuck.

[0008] A variety of interchangeable jaws are available for chucks to clamp specific workpieces. These interchangeable jaws are screwed onto adjustable base jaws or, in the case of special chucks, can be replaced individually.

[0009] DE 27 49 626 A1 discloses a chuck for lathes with a chuck body in which a piston is arranged which is axially movable between a clamping and a release position and which is in driving connection with driving jaws which are radially movable in the chuck body, and with clamping jaws which are connected to the driving jaws by means of manually decoupleable drivers, in the decoupling position of which the clamping jaws can be radially withdrawn from the chuck body, wherein the drivers are designed as slides which are arranged transversely to the respective driving and clamping jaw and which are movable in a radial plane of the chuck body and are in engagement with the clamping jaw in the coupling position via a toothing.

[0010] DE 21 04 904 C shows a clamping device for lathes with quick change of the top clamping jaws from the base jaws, whereby the base jaws can be coupled to the top clamping jaws by radial displacement. The radial displacement takes place via keys with laterally perforated longitudinal ribs, splines or the like.

[0011] DE 19 22 499 A discloses a "jaw chuck with base jaws carrying interchangeable top jaws." The present disclosure relates to a jaw chuck in which the base jaws are mounted in the chuck body for clamping a workpiece over a predetermined clamping range. Each base jaw is equipped with several optionally usable contact surfaces for differently designed top jaws. A dovetail-shaped groove running in the longitudinal direction of the jaw is provided for guiding and securing the top jaw with a wedge-shaped projection. A cross wedge is arranged on this groove, which has a toothing onto which top jaws equipped with counter-teeth can be placed in various radial positions.

[0012] DE 19 20 345 A discloses a "chuck for machine tools." The chuck is designed for power operation and is equipped with a drive piston that is axially movable within the chuck body. The drive piston engages radially guided clamping jaws via inclined wedge hooks and can be disengaged from the clamping jaws by turning. The chuck has two sets of alternately usable base jaws, with at least one set being designed for radial displacement of the top jaws by means of serrations, and the other set being equipped with fixed stop surfaces for radial position determination and a laterally clampable dovetail guide for securing the top jaws. A locking pin is provided for this purpose.

[0013] The disadvantage of these disclosures is that the use of different interchangeable heads is time-consuming and requires the storage of various top jaws.

[0014] The object of the invention is therefore to provide a clamping jaw system in which the set-up times are reduced to a minimum while maintaining the same repeatability. Disclosure of the invention

[0015] The problem is solved by the features of the main claim. Embodiments and further developments are the subject of the further claims following the main claim.

[0016] A clamping jaw system comprising a combination of at least two differently designed top jaws, each arranged on a base jaw, for holding workpieces is disclosed. The top jaws are, on the one hand, the jaws of a quick-change system or a quick-change jaw, and, on the other hand, the jaws of a system with pointed teeth or a jaw with pointed teeth. At least one top jaw of the respective type mentioned can be arranged on each base jaw.

[0017] The jaws of the quick-change system are used primarily for small batches. They are typically more expensive and more precise in use.

[0018] However, for certain clamping tasks, chucks with a centering point for the workpieces to be clamped are also required. The chuck typically has a device that allows the jaws to first be brought up to the workpiece and pressure equalized between them, only then to clamp with full force. These chucks with a centering point are required for large-scale production.

[0019] The base jaw for holding the respective top jaws is specifically designed as a power chuck. Power chucks are used for clamping workpieces on machine tools. The power chuck is a hydraulic chuck, which is used primarily in lathes. Hydraulic power chucks are used, for example, in CNC machines. On these machines, the power chuck can either clamp the workpiece automatically after it has been loaded or it can be controlled manually, for example, by a pedal. In both cases, however, the use of a chuck key is not necessary.

[0020] The power chuck offers increased safety through a uniform clamping force. This compensates for any loss of clamping force during operation. The power chuck comprises many components that must work together optimally. The power chuck typically consists of a power chuck body, a power chuck cover, movable pistons, levers, and additional weights. The weights are pushed outwards by centrifugal forces, and the force is transferred inwards in the opposite direction to the base jaw via a two-sided lever. This serves to compensate for the jaw centrifugal forces and the resulting reduction in clamping force. Therefore, the power chucks can also be used at high speeds. Operating at higher speeds increases the productivity of the lathe. The uniform clamping force ensures greater safety because any loss of clamping force is compensated for.

[0021] The power chuck body can be a wedge-hook chuck, angle-lever chuck, power-operated finger chuck, or round-bore chuck. The wedge-hook principle is one of the most commonly used in clamping devices, where wedge surfaces convert the axial movement of a drawtube into a radial movement of the jaws. This enables high resistance with high centering accuracy and high clamping force. Finger chucks are frequently used for machining tubular and thin-walled workpieces. The power chuck can be designed with or without through-holes. The through-holes can have different sizes or diameters.

[0022] The power chuck can be designed as a two-, three-, four-, or six-jaw chuck. It can be designed with or without centrifugal force compensation. The power chuck has a flat guide or a multi-jaw guide, with or without a central lubrication system. The base jaw can be combined with serrations or with the quick-change system. The serrations can be flat. The quick-change system can have straight teeth.

[0023] The clamping jaw system according to the invention has the advantage that the required different jaw systems no longer need to be interchanged. This significantly reduces the need to keep stocks of the other jaw. Furthermore, changeover times for the two jaw systems are eliminated.

[0024] Further advantages and advantageous embodiments of the invention can be found in the following description of the figures, the drawings and the claims.

[0025] An exemplary embodiment of the inventive solution is explained in more detail below with reference to the attached schematic drawings. It shows: Fig. 1 shows a chuck with different toothings for different jaws, where Fig. 1a) the chuck in an oblique view, Fig. 1.b) a first toothing for a first attachment jaw, a pointed toothed jaw, Fig. 1c) a second toothing for a quick-change jaw, both shown enlarged in a detailed view, Fig. 2 shows a pointed toothed device, where Fig. 2a) a view from the side, Fig. 2b) is a front view and 2c) is an oblique view from above, Fig. 3 represents a quick-change jaw, where Fig. 3a) a view from the side, Fig. 3b) is a front view and 3c) is an oblique view from above, Fig. 4 shows the assembly of a pointed jaw, where 4a) shows the pointed jaw inserted into a chuck from the side of the chuck, and Fig. 4b) shows a screwing in with an assembly tool from above in a longitudinal section, and Fig. 4c) shows a side view of the pointed jaw and Fig. 4d) a section through the pointed jaw, Fig. Figure 5 shows the assembly of a quick-change jaw, where 5a) shows the quick-change jaw inserted into a chuck from the side of the chuck, and Fig. 5b) shows a screwing in with an assembly tool from below or from the side in a longitudinal section, and Fig. 5c) a view of the quick-change jaw from the side and Fig. 5d) shows a section through the quick-change jaw, Fig. 6 shows a cross section through the chuck and Fig. 7 shows a longitudinal section through the chuck with a quick-change jaw and a view of the pointed jaw.

[0026] In Fig. 1a) shows a chuck 10. The chuck 10 is designed as a power chuck 10. The chuck 10 is, in particular, a wedge-hook chuck with or without centrifugal force compensation. The chuck 10 designed as a power chuck is made of high-quality steel. It has an integrated lubricant reserve. A through-bore 12 is formed on the chuck 10. At least two top jaws are arranged on the chuck 10. This is, on the one hand, at least one quick-change jaw and, on the other hand, at least one jaw with pointed teeth. These different top jaws are held and mounted on differently designed toothings. The jaw with pointed teeth is arranged on a toothing 14. The toothing 14 can be an imperial or metric toothing 14. The quick-change jaw is arranged on a straight toothing 16 of the base jaw 18. This creates a clamping jaw quick-change system 20.

[0027] Power chucks 10 are used for clamping workpieces on machine tools. The power chuck 10 is a hydraulic chuck 10, which is particularly used in lathes. Hydraulic power chucks 10 are used, for example, in CNC machines. On these machines, the power chuck 10 can either clamp the workpiece automatically after loading or be manually controlled, for example, by a pedal.

[0028] The power chuck 10 offers increased safety through a uniform clamping force. This compensates for any loss of clamping force during operation. The power chuck 10 comprises many components that must work together optimally. The power chuck 10 typically comprises a power chuck body, a power chuck cover, movable pistons, levers, and additional weights. The weights are pushed outward by centrifugal forces, and the force is transferred inward in the opposite direction by a two-sided lever to the base jaw 18. This serves to compensate for the jaw centrifugal forces and the resulting reduction in clamping force. Therefore, the power chucks 10 can also be used at high speeds. Operating at higher speeds increases the productivity of the lathe. The uniform clamping force ensures greater safety because any loss of clamping force is compensated for.

[0029] The power chuck body of the power chuck 10 can be a wedge-hook chuck, angle lever chuck, power-operated finger chuck, or round-bore chuck. The wedge-hook principle is one of the most commonly used in the clamping device field, whereby the axial movement of a drawtube is converted into a radial movement of the jaws by means of wedge surfaces. This enables high resistance with high centering accuracy and a high clamping force. Finger chucks are frequently used when machining tubular and thin-walled workpieces. The power chuck 10 can be designed with or without a through-hole 12. The through-holes 12 can have different sizes or diameters.

[0030] The power chuck 10 can be designed as a two-, three-, four-, or six-jaw chuck. It can be designed with or without centrifugal force compensation.

[0031] Fig. 1b) shows a detailed view of the serration 14 in an enlarged view. The serration 14 is used to attach a serrated jaw or clamping jaw to a power chuck.

[0032] Fig. 1c) shows a detailed view of the straight toothing 16 of the base jaw 18, which is designed for mounting a quick-change jaw.

[0033] Fig. 2a) shows a pointed toothed jaw 22 or clamping jaw as a top jaw for the power chuck 10 from Fig. 1a). The pointed jaw 22 has on its underside a groove directed towards the pointed toothing 14 of Fig. 1 adapted, complementary serrations on their lower edges so that they can be placed on the serration 14 and arranged thereon. The serrated jaw 22 has a sliding carriage 24 for the serration. With this sliding carriage 24, the serrated jaw 22 can be mounted on the power chuck 10 from Fig. 1a) and can be moved in a groove to the appropriate position.

[0034] In Fig. 2b) the top jaw, which is designed as a pointed toothed jaw 22, is shown with the sliding carriage 24 from the side.

[0035] Fig. 2c) shows the pointed-toothed jaw 22 in an oblique view slightly from above. Two openings 26, 28 are formed on the upper side of the pointed-toothed jaw 22.

[0036] In Fig. 3 shows a quick-change jaw 30.

[0037] Fig. 3a) shows the quick-change jaw 30 from the side. The quick-change jaw 30 has a sliding carriage 32 for the quick-change jaw 30. A coarse toothing 34 is formed on the sliding carriage 32. This coarse toothing 34 is designed such that it fits into the straight toothing 16 of the base jaw 18 made of Fig. 1 and can be secured there in its appropriate position. The quick-change jaw 30 can be designed with block teeth.

[0038] Fig. 3b) sets up the quick-change jaw 30 with its sliding carriage 32 for insertion into its guide in the power chuck 10 Fig. 1a).

[0039] Fig. 3c) shows the quick-change jaw 30 in a view obliquely from above, with two openings 36, 38 visible, which serve to accommodate connecting screws.

[0040] Both the top jaw, which is designed as a pointed, serrated jaw 22, and the top jaw, which is designed as a quick-change jaw 30, can be designed as a soft top jaw or a hard top jaw. Soft top jaws are used for the precise clamping of previously machined workpieces whose clamping surfaces must not be damaged. This type of jaw is machined to the respective clamping diameter under clamping pressure and offers high repeatability. Hard top jaws are hardened for universal use.

[0041] Fig. 4 shows the mounting of a pointed jaw 22 on the power chuck 10.

[0042] In Fig. 4a) the pointed toothed jaw 22 with the sliding carriage 24 is inserted or pushed into a groove 40 for the pointed toothed jaw 22.

[0043] Fig. 4b) shows the fastening of the pointed jaw 22 with a first assembly tool 42, which is applied from above. This causes the pointed jaw 22, with its pointed teeth formed on its underside, to be pressed against the pointed teeth 14 of Fig. 1b) and meshed with it. This creates a firm hold for the pointed, toothed jaw 22.

[0044] Fig. 4c) represents the pointed toothed jaw 22, which slides with its slide 24 into the groove 40, which is Fig. 4d) is inserted and then locked by the teeth.

[0045] In Fig. Figure 5 shows the assembly of a quick-change jaw 30.

[0046] Fig. 5a) shows how the quick-change jaw 30 with its sliding carriage 32 is inserted as a quick-change system 20 into a groove 44 for the corresponding sliding carriage 32.

[0047] In Fig. 5b) shows how the quick-change jaw 30 is secured by attaching another assembly tool 46 from below or from the side by moving the base jaw 18 toward the quick-change jaw 30. The straight toothing of the base jaw 18 meshes with the straight toothing 34 of the quick-change jaw 30, so that the latter can be firmly connected to the base jaw 18.

[0048] Fig. 5c) shows how the quick-change jaw 30 with the straight toothing 34 is inserted into the groove 44 so that the likewise straight toothing of the base jaw 18 can be guided from below to the underside of the quick-change jaw 30. For this purpose, the assembly tool 46 is applied from the side, and by actuating the assembly tool 46, the base jaw 18 is moved toward the quick-change jaw 30. After the base jaw 18 is moved toward the quick-change jaw 30, the toothing 34 engages the straight toothing 16 of the base jaw 18, creating a secure connection.

[0049] Fig. Figure 6 shows a cross-section through the power chuck 10. A through-hole 12 is formed. Two different top jaws are arranged: the quick-change jaw 30 and two pointed jaws 22. A cutting direction A - A is indicated.

[0050] Fig. 7 shows the longitudinal section, which in Fig. 6 is marked A - A. The quick-change jaw 30 is fastened by the engagement of the straight toothing 16 of the base jaw 18 with the toothing of the quick-change jaw 30.

[0051] The fastening of the pointed toothed jaw 22 with the sliding carriage 24 is carried out via the pointed toothing 14 made of Fig. 1b, which is mounted on the power chuck 10 Fig. 1a) is formed by meshing with the pointed toothing which is formed on the underside of the pointed toothed jaw 22, respectively laterally on or above the sliding carriage 32.

[0052] The assembly tools 42 for the pointed jaw 22 and 46 for the quick-change jaw 30 can be of the same or different design.

[0053] All features presented in the description, the following claims and the drawings may be essential to the invention both individually and in any combination with one another. List of reference symbols 10 chucks 12 through holes 14 fine toothing 16 straight teeth 18 Base jaw 20 clamping jaw quick-change system 22 pointed toothed jaw 24 sliding carriages with fine toothing 26 Opening pointed toothed jaw 28 Opening pointed toothed jaw 30 quick-change jaw 32 sliding carriage quick-change jaw 34 coarse toothing 36 Opening quick-change jaw 38 Opening quick-change jaw 40 groove mounting slide 24 42 Assembly tool for pointed jaw 22 44 Slot for slide carriage 32 46 Assembly tool for quick-change jaw 30

Claims

[1] Clamping jaw system for a machine spindle of a machine tool for clamping workpieces with a chuck (10), comprising at least two base jaws (18), characterized by , that at least two different top jaws (22, 30) are arranged on the chuck (10), wherein one top jaw is designed as a pointed toothed jaw (22) and another top jaw is designed as a quick-change jaw (30), wherein a straight toothing (16) or helical toothing is formed on the base jaw (18), which serves to mesh with a corresponding toothing (34) on the quick-change jaw (30), and the base jaw (18) is moved towards the quick-change jaw (30) by the use of an assembly tool (46), and the toothing (16) of the base jaw (18) meshes with the toothing (34) of the quick-change jaw (30). [2] Clamping jaw system according to claim 1, characterized by , that the chuck (10) is designed as a power chuck (10). [3] Clamping jaw system according to one of claims 1 or 2, characterized by , that the chuck (10) has an inch or metric serration (14) for meshing with a further serration formed on the serrated jaw (22). [4] Clamping jaw system according to one of the preceding claims, characterized by , that the clamping jaw system has three top jaws (22, 30) arranged on the chuck (10), two of which top jaws (22) are designed as pointed toothed jaws (22). [5] Clamping jaw system according to one of the preceding claims, characterized by , that the pointed toothed jaw (22) can be inserted into a groove (40) for receiving the sliding carriage (24) by means of a sliding carriage (24). [6] Clamping jaw system according to claim 5, characterized by, that a connection of the pointed toothed jaw (22) is made via a toothing arranged on one side of the pointed toothed jaw (22), which rests on the pointed toothing (14) of the chuck (10). [7] Clamping jaw system according to claim 6, characterized by , that the connection of the pointed toothed jaw (22) with the chuck (10) is effected by the use of an assembly tool (42) by moving the pointed toothed jaw (22) in the direction of the chuck (10), so that the pointed toothing of the pointed toothed jaw (22) meshes with the pointed toothing (14) of the chuck (10). [8] Clamping jaw system according to one of the preceding claims, characterized by that the chuck (10) has a flat guide or a multi-jaw guide for the different top jaws (22, 30).

Images