Clamping system
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- HAINBUUFU GMBH SHUPANENDE TEHINIKU
- Filing Date
- 2026-01-16
- Publication Date
- 2026-07-30
Smart Images
Figure EP2026051064_30072026_PF_FP_ABST
Abstract
Description
[0001] 0091P0052WO Page 1 15 January 2026
[0002] clamping system
[0003] SCOPE OF APPLICATION AND STATE OF THE ART
[0004] The invention relates to the field of clamping systems with clamping jaws, in particular to the field of clamping systems for clamping workpieces.
[0005] Such clamping systems are known, for example, in the form of 3- or 4-jaw chucks, but can also be equipped with only two jaws. The jaws are movable relative to a base and relative to each other to securely clamp a workpiece. In particular, the jaws can be moved radially in the direction of a common central axis. Clamping systems of this type, as well as those according to the invention, are designed in particular for mounting on a rotary spindle to clamp workpieces for machining purposes.
[0006] In a clamping system of this type, the clamping jaws each have a base jaw that can be moved relative to the base, as well as a replaceable top jaw mounted on the base jaw. On the outside of the top jaw is a clamping area that rests against the workpiece to be clamped. Specifically, the clamping areas of the jaws can be oriented towards a common central axis to clamp a workpiece from the outside. However, an arrangement is also possible in which the clamping areas point outwards to clamp a workpiece from the inside.
[0007] Jaw systems consisting of a base jaw and a top jaw are widely known. They offer several advantages. The clamping system can be easily adapted to different workpiece geometries, as only the top jaws, not the base jaws, need to be replaced. Quick replacement in case of wear is also possible.
[0008] However, established systems with base and top jaws also have disadvantages, particularly regarding the automated attachment of the top jaw. The coupling process of known top jaws is complex and difficult to implement with robots, as, in addition to the relative movement between the top and base jaws, additional locking devices, such as fastening screws, often need to be handled. Furthermore, there is a risk of chips entering the contact area between the base and top jaws. If this goes unnoticed, the top jaw cannot assume its intended position relative to the base jaw. This results in the workpiece clamping position deviating from the intended position, and the machining quality of the workpiece is correspondingly reduced.
[0009] TASK AND SOLUTION
[0010] The object of the invention is to design a clamping system with base jaws and top jaws that can be attached and replaced on them in such a way that automated changing is facilitated and disruptions to operation due to contamination are reduced.
[0011] According to the invention, a clamping system is proposed for this purpose, which is preferably designed in a special way with regard to two aspects of the invention described below, wherein the two aspects of the invention can also be realized independently of each other, but are preferably implemented together on a clamping system.
[0012] According to a first aspect of the invention, the clamping system, as described above for generic clamping systems, has a plurality of clamping jaws which are radially displaceable relative to each other and relative to a central axis of the base of the clamping system by displacing the base jaws of the clamping jaws relative to the base. These base jaws are preferably removable from the base.
[0013] Preferably, three or more such clamping jaws, each with a base jaw, are provided, which can be displaced together in the direction of or away from the central axis. In clamping systems that rotate as intended, the central axis coincides with the axis of rotation of the tool spindle.
[0014] However, two clamping jaws may also suffice for certain applications. Preferably, the clamping system further comprises a common actuating element which, by displacement, indirectly displaces the base jaws radially relative to each other. In particular, the force transmission from the common actuating element to the base jaws can be effected by means of a wedge drive.
[0015] The clamping jaws each have a top jaw mounted on the base jaw, on the radially inner or radially outer surface of which a clamping area is provided for contact with a workpiece to be clamped. Radially inner clamping areas are used for external clamping of workpieces and surround the workpiece for this purpose. Radially outer clamping areas are used for internal clamping of workpieces. Preferably, a clamping system according to the invention is provided for both external and internal clamping, whereby this can be achieved by means of identical top jaws or by means of different sets of top jaws for internal and external clamping.
[0016] The clamping jaws feature a coupling system for attaching the top jaw to the base jaw, designed to enable automated jaw changes using a loading device and, in particular, a robot. This quick and reliable changeover capability increases the flexibility of using clamping systems of this type.
[0017] The coupling system comprises corresponding positive locking elements on the base jaws and the top jaws, which can be moved into a locked coupling position by a relative movement of the top jaw against the base jaw. In the locked coupling position, the top jaws are attached to the base jaws in such a way that a force applied to the top jaws in a radial direction inwards and / or outwards does not cause them to separate from the base jaws.
[0018] The relative movement intended for coupling and locking comprises two movement components that follow each other sequentially, but can also superimpose during a transition phase. These movement components are an axial insertion component for establishing the coupling, i.e., the axial engagement of the positive locking elements, and a rotary locking component for positive locking in the axial direction.
[0019] The coupling system is therefore designed to be primarily engaged by a rotational movement of the top jaw relative to the base jaw, and to be unlocked by a counter-rotational movement. A radial force, such as that applied during clamping, cannot, however, cause unlocking. In particular, the described coupling and locking sequence also allows the same coupling system, possibly implemented in different top jaws, to be used for both internal and external clamping. This is advantageous compared to systems where the locking mechanism involves a radial movement component, creating the risk of the lock being released during clamping.
[0020] Furthermore, locking via a rotary motion is also advantageous because it can be easily implemented by a robot or other feeding mechanism. In the case of a robot, ideally, the mobility of a robot gripper via a robot arm alone is sufficient to achieve the axial coupling and the rotary motion, without the need for additional actuators on the changeover manipulator.
[0021] Preferably, the coupling system is designed as a bayonet coupling system. This means that the locking component of the coupling movement, i.e., the rotation of the top jaw relative to the base jaw, occurs at least partially without any accompanying axial displacement. Thus, during the locking process, the top jaw is rotated, at least in phases, only about a bayonet axis, without any simultaneous axial movement component. The bayonet axes of the clamping jaws preferably extend parallel to the central axis of the clamping system.
[0022] The bayonet coupling system typically features a bayonet pin with a distal expansion and a corresponding receiving contour with radial retention sections designed to securely engage the expansion, which is inserted by relative rotation. The bayonet pin can be located on either the mounting jaw or the base jaw. However, it is preferred that the bayonet pin is located on the base jaw and the receiving contour is located on the mounting jaw.
[0023] The radial retaining sections extend from the outside into the aforementioned receiving contour and thus, together with further sections of the receiving contour, define areas for the positive-locking engagement of the bayonet pin's expansions. These expansions extend outwards from the bayonet pin.
[0024] In the circumferential direction, the retaining sections and the expansions are not continuous, in order to allow the bayonet pin to be drawn into the receiving contour during the axial insertion phase of the coupling relative movements. From this relative position, the rotational movement takes place, causing the expansions of the bayonet pin to move behind the retaining sections, thus preventing axial separation.
[0025] A clamping connection is preferably not present during locking. However, the receiving contour and the bayonet pin are preferably joined with virtually no play when locked. Very limited remaining relative movement is considered advantageous so that the mounting jaw can ideally conform to the outer or inner contour of the workpiece. It is particularly preferred if the bayonet pins have a continuously widening shape towards a distal end, at least in a portion of their length. In particular, the widenings preferably have a conical shape, especially with an angle to the bayonet axis of between 10° and 40°. The holding sections of the receiving contour preferably have correspondingly inclined holding surfaces so that the corresponding surfaces are in contact under load.
[0026] The angled design has proven advantageous for improving the transfer of clamping forces from the top jaw to the base jaw. The continuously widening shape increases the contact area and reduces surface pressure. Furthermore, this allows for greater material thickness at the force-bearing radial holding sections of the clamping contour.
[0027] Preferably, a clamping system according to the invention includes an anti-rotation device. This anti-rotation device limits or completely prevents the rotational movement of an attached top jaw during clamping. The anti-rotation device is designed such that, after a coupling and locking process by means of a feeding mechanism or a robot, it prevents the top jaw from rotating backward under the clamping load and / or from rotating the top jaw too far and beyond a target position during the locking movement.
[0028] In particular, it is preferred that the anti-rotation device forms a positive locking block that limits the rotational mobility of the top jaw.
[0029] The anti-rotation device preferably comprises a movable retaining element that can be shifted between a non-locking and a locking position. This retaining element forms a stop that limits rotation in the locking position. Rotation of the top jaw in the opposite direction is preferably prevented by a fixed second stop on the base jaw or the base.
[0030] The movable retaining element can be pressed into a non-blocking position, in which it does not obstruct the desired separation of the top jaw from the base jaw. Preferably, the retaining element is associated with a return spring that applies force to the retaining element in the direction of the blocking position. This simplifies the design of the anti-rotation device, as the blocking position is automatically established when the force temporarily ensuring the non-blocking position is removed.
[0031] The force applied to the holding element to achieve the non-locking positions is preferably applied externally, i.e., not by elements of the clamping system itself. In particular, this is preferably done by the feeding mechanism or the robot by which the top jaw is fed to or detached from the clamping system.
[0032] A particularly advantageous design provides that the movable retaining element is designed as a retaining element that can be pressed in towards the central axis. This means that an axial approach, for example by a robot gripper, can be used to establish the non-blocking position, and / or that an axial separation, for example by a robot gripper, can be used with the assistance of the aforementioned spring to establish the blocking position.
[0033] Preferably, the top jaw has a pressure surface for temporarily pressing down the retaining element. This makes it possible, when feeding a top jaw for the purpose of coupling the top jaw, to initially and / or intermittently press down the retaining element indirectly via the top jaw before the top jaw is rotated by the rotary movement relative to the base and relative to the retaining element into a usable position in which the contact between the pressure surface and the retaining element is lost, so that the retaining element can move into its locking position, for example under the action of the aforementioned return spring.
[0034] The receiving contour, which is provided in particular on the top jaw, is preferably surrounded by a skirt completely and without interruption in order to reduce the ingress of chips between the top jaw and the base jaw.
[0035] To achieve a more thorough seal, a gasket is preferably provided. This gasket closes any remaining gap between the base jaw and the attached top jaw, which is in its operating position. In particular, this gasket can be elastic. Suitable materials for the elastic gasket include polyurethane or rubber. The clamping forces originating from the workpiece and introduced into the top jaw from the outside or inside during clamping are at least partially transferred to the base jaw via the coupling system, especially via the bayonet pin. However, it is preferred if the top jaw and the base jaw are matched to each other in such a way that the clamping force is not transmitted solely via the bayonet pin and the receiving contour.
[0036] It is particularly proposed that at least one support surface be provided on the base jaw, spaced apart from the bayonet pin and radially offset from the bayonet pin. The top jaw rests against this support surface when a force is applied in the direction of the central axis or away from the central axis. The support surface is preferably oriented such that its normal vector extends parallel to the central axis or forms an angle of less than 10° with it.
[0037] Radial inner support surfaces of the bayonet pin serve to transmit force from the top jaw to the base jaw during internal clamping. Support surfaces on the outer side of the bayonet pin serve to transmit force from the top jaw to the base jaw during external clamping.
[0038] Since, due to the coupling system according to the invention and the locking achieved by rotary movement, at least the base jaw does not have to be specifically aligned for internal or external clamping, it is preferably provided that support surfaces are provided on the base jaw opposite the bayonet pin, both radially inwards and radially outwards.
[0039] For force transmission at the at least one support surface, which preferably extends planarly in the radial direction, it is advantageous if the radial distance between the bayonet pin and the support surface is relatively large. Preferably, this radial distance is greater than the axial distance between a distal end of the bayonet pin and the support surface.
[0040] The second aspect of the invention relates to the detection of whether the top jaw has reached its target position during coupling. This second aspect complements the first aspect with regard to the problem that the ingress of chips and contaminants during the changeover is difficult to completely rule out, even with a design featuring a skirt and seal as described above. The following aspect of the invention makes it possible to detect such a case and take appropriate measures. It is proposed that the clamping system has a pneumatic testing system to check the correct contact of the top jaw with the base jaw. This pneumatic testing system has a pressure channel in the base jaw, which can be pressurized with positive or negative pressure during the contact of the top jaw and which is closed at the end by a closing surface of the top jaw when the contact is correct.
[0041] It is therefore intended that the closing surface of the top jaw, which is preferably located on an inner side of the receiving contour described above, rests against an opening of the pressure channel in the coupled state and closes it. This allows an overpressure to be generated in the pressure channel after the top jaw is coupled, and it can be determined by measurement whether the closing surface is in its intended position. In particular, this can be done by determining the pressure that develops or by measuring the flow rate into the pressure channel. If the expected back pressure is not reached or if the flow rate exceeds an acceptable limit, this indicates that contamination or chips are preventing the top jaw from being seated correctly, and the problem must be rectified before machining continues.
[0042] The closing surface of the top jaw and the clamping area of the top jaw are preferably oriented in opposite directions. This ensures that the contact of the top jaw against the base jaw, which closes the pressure channel, coincides with the correct positioning of the clamping area. In particular, the clamping area and the open end of the pressure channel are preferably oriented radially inwards with respect to the clamping system.
[0043] It is advantageous if the pressure channel opens into at least two openings on the base jaw, which, when the top jaw is correctly fitted, are each closed by a closing surface of the top jaw. Such a pressure channel with two openings leads to increased reliability in verifying the coupled and locked state. The two openings are preferably provided on opposite sides of the base jaw, particularly on two different sides of the bayonet pin. Specifically, the openings can be provided on the flared sections, preferably in the conical segment-shaped area described above.
[0044] As described above, depending on the design of the clamping system, it can be advantageous for it to include a movable retaining element that can be shifted between a position that does not block the movement of the top jaw relative to the base jaw and a blocking position. This can be provided in the manner described with a rotary locking mechanism for the top jaws. However, other coupling systems are also possible in which a different type of locking component movement is provided, which is nevertheless also secured by a movable retaining element.
[0045] If such a movable retaining element is provided on the base jaw, it can be advantageous if the pneumatic testing system also has an air outlet that can be opened and closed by moving the retaining element. This allows for a check that not only verifies the correct locking of the top jaw but also secures this locked position against unintentional unlocking.
[0046] Preferably, the pneumatic testing system is designed to prevent pressure build-up in the pressure channel or to only slightly impede the airflow through the pressure channel when the holding element is in its position that does not block the mounting jaw. Preferably, the holding element is operatively coupled to the air outlet in such a way that when the holding element is in its blocking position, the air outlet is essentially closed.
[0047] Preferably, the pressure channels leading to the holding element and those serving to position the top jaw are interconnected. It is generally sufficient to detect a condition in which either the holding element is not in its blocking position or the top jaw is not in its correct position, as both are equally sufficient to conclude that machining cannot begin.
[0048] In particular, a common pressure channel is preferably provided, which supplies all clamping jaws with compressed air and, in particular, preferably branches in such a way that both the position of the holding element and the correct coupling of the top jaws are checked for several clamping jaws simultaneously. If the airflow is too high and / or the expected pressure is not achieved, at least one clamping jaw is in a condition that requires further investigation and correction. BRIEF DESCRIPTION OF THE DRAWINGS
[0049] Further advantages and aspects of the invention will become apparent from the claims and from the following description of preferred embodiments of the invention, which are explained below with reference to the figures.
[0050] Fig. 1 shows a first embodiment of a clamping system according to the invention in the form of an exemplary three-jaw chuck in overall view.
[0051] Fig. 2 shows the clamping system in a sectional view.
[0052] Fig. 3 shows a single clamping jaw of the clamping system with the top jaw removed from a base jaw.
[0053] Figures 4A and 4B show the attachment jaw from different perspectives.
[0054] Fig. 5 shows the coupling area of the base jaw and the top jaw in the cut-away state.
[0055] Figures 6A to 6E show the coupling of the top jaw to the base jaw.
[0056] Fig. 7 shows the relocation of the clamping jaw for the purpose of clamping and releasing.
[0057] Fig. 8 shows a second embodiment of a clamping system according to the invention with three clamping jaws in overall view, wherein one top jaw has been removed to clarify the underlying base jaw.
[0058] Fig. 9 shows the clamping system of Fig. 8 in a partially cutaway view.
[0059] Figs. 10 and 11 show the top of the base jaw and the bottom of the top jaw and a coupling system provided here for coupling the top jaw.
[0060] Figures 12A to 15B show the coupling of the top jaw to the base jaw.
[0061] Figures 16 and 17 illustrate the implementation of a pneumatic testing system in the second embodiment of Figure 8. DETAILED DESCRIPTION OF THE EXECUTION EXAMPLES
[0062] Fig. 1 shows a clamping system 10 according to the present invention. The clamping system 10 according to this embodiment is designed in the form of a three-jaw chuck and has three clamping jaws 30 that can be displaced radially along the arrows 4 and which have inwardly pointing clamping areas 70 that are aligned in the direction of a central axis 2.
[0063] Fig. 2 shows the clamping system 10 in a sectional view, from which it can be seen that the clamping jaws 30 are each divided into two parts.
[0064] The clamping jaws 30 have a base jaw 40 which, in the course of using the clamping system 10, always remains on a base 20 of the clamping system and which can be displaced radially by means of a common actuating element 24 and a wedge gear 26.
[0065] The clamping jaws 30 each have a top jaw 60, which is designed to be easily and automatically interchangeable. The top jaws 60 provide the clamping areas 70, which come into direct contact with the workpiece when it is clamped. Replacing the top jaws 60 also replaces the clamping area 70. Replacement may be necessary due to wear or to use a top jaw 60 that is particularly well-suited to the workpiece being machined in terms of its geometry or material.
[0066] Fig. 3 shows an enlarged view of a clamping jaw 30, with the top jaw 60 removed from the base jaw.
[0067] It can be seen that the base jaw 40 has a support base 50 that extends outwards through a recess in a seal 80. The support base 50 represents the part of the base jaw 40 to which the top jaw 60 is coupled. The base jaw thus has an exposed extension that serves to transmit the forces from the top jaw 60 to the base jaw 40. However, there are no recesses in the base jaw 40 in which chips could collect.
[0068] For the purpose of securing the top jaw 60, the support base 50 has a special geometry. It features various retaining contours 54 implemented as overhangs. One overhang is provided at the bottom of the support base 50, as shown in Fig. 3. Further smaller overhangs are provided on both sides of the support base 50 and are separated from each other by grooves 55. A bore 56 is provided on the side of the support base facing upwards in Fig. 3, into which an outwardly spring-loaded pin is inserted as a retaining element 46.
[0069] Figures 4A and 4B illustrate the construction of the top jaws 60. It can be seen that a recess 61 is provided in the top jaw 60 on the side facing the base jaw 40, which is completely surrounded by a skirt 62. Corresponding to the retaining contours 54 on the support base 50, retaining contours 64 are provided in the recess 61. The retaining contours 54 and 64 are aligned such that the top jaw 60 can be pushed in a straight line onto the support base 50 in a defined radial position relative to the base jaw 40 and can then be locked onto it by a subsequent relative radial movement. This will be explained in more detail below.
[0070] The top jaw has a chamfer 66, the meaning of which will be explained later.
[0071] Fig. 5 shows a clamping jaw 30 again in a sectional view with the top jaw 60 attached. It can be seen that the retaining contours 54, 64 abut each other and thus prevent purely axial removal of the top jaw 60. Similarly, the lateral retaining contours 54, 64, which are not arranged in the sectional plane of Fig. 5, are also engaged with each other.
[0072] Furthermore, as can be seen in Fig. 5, the pin-shaped retaining element 46 is pushed outwards by the force of the spring device 44 and thereby presses against a retaining surface 65 on the inside of the mantle of the attachment jaw.
[0073] The top jaw 60 is thereby pressed radially outwards relative to the base jaw 40 and the support base 50. This movement is limited by a closing surface 68 provided on the inside of the top jaw 60 opposite it. This closing surface faces an outer surface of the support base 50, where a pressure channel 92 opens.
[0074] The pressure channel 92 is connected to a pressure source and a measuring device in a manner not shown in detail. When gas, particularly air, is supplied through the pressure channel 92, it allows verification of whether the closing surface 68 seals the pressure channel or whether gas can escape. If the expected back pressure is reached in the pressure channel 92, or if the flow rate is below an acceptable limit, it can be concluded that no relevant gap remains between the closing surface 68 and the support base 50, and that the top jaw is therefore in its intended position relative to the base jaw 40. If, on the other hand, the expected back pressure is not reached, or if an excessively high flow rate is detected, this indicates that chips or other contaminants are preventing the top jaw 60 from assuming its intended position.
[0075] Figures 6A to 6E illustrate, using a schematic sectional view of the essential components of the clamping system 10 for coupling, the coupling of an attachment jaw 60.
[0076] Fig. 6A shows the clamping jaw 30 in its separated state. No top jaw 60 is yet mounted on the round jaw 40 and its support base 50. The top jaw 60 shown in Fig. 6A is fed by a feeding device, in particular by a robot or by a feeding device permanently installed on the machine tool. The top jaw 60 is usually taken from a magazine of top jaws beforehand. In this case, the feeding is carried out by a robot, which guides the top jaw 60 in a manner not shown.
[0077] As shown in Fig. 6A, the top jaw 60 and the base jaw 40 are already in their respective final positions before coupling. The top jaw can be attached solely by linear displacement of the top jaw 60.
[0078] The placement begins with a relative position in which the holding contours 54, 64 on the support base 50 and on the mounting jaw 60 do not align with each other and can therefore be guided past each other without collision.
[0079] Starting from the relative position shown in Fig. 6A, the attachment jaw is pushed onto the support base 50, so that the support base 50 enters the recess 61. In the position shown in Fig. 6B, a chamfer 66 on the inside of the attachment jaw 60 comes into contact with the distal end of the pin-shaped retaining element 46 and, with continued movement, presses it in against the force of the spring assembly 44. Fig. 6C illustrates this.
[0080] The axial approach movement ends in the relative position of Fig. 6D. The retaining element 46 is now completely pressed into the support base 50 and the retaining contours 54, 64, as well as the further lateral retaining contours 54, 64, which are not visible in Figs. 6A to 6E, are each guided past each other.
[0081] Furthermore, the skirt 62 of the top jaw comes into contact with a sealing lip 82 of the seal 80 during this phase, so that the support base 50 and the recess 61 of the top jaw 60 are now isolated from the environment, and the risk of ingress of chips or contaminants is now low. The final relative movement of the top jaw 60 relative to the base jaw 40 can now take place, during which the retaining contours 54, 64 engage with each other. Fig. 6E illustrates this. Assisted by the spring device 44, the handling robot moves the top jaw 60 upwards relative to the base jaw 40 as shown in Fig. 6E, thereby causing the retaining contours 54, 64 to move into their locking position. At the same time, the closing surface 68 of the top jaw 60 is moved against a lower side surface of the support base 50 and closes the pressure channel 92 there.Ensuring that the pressure channel 92 is closed in the desired manner and that no impurities or chips prevent the closing surface from contacting the support base guarantees that the top jaw 60 is in its intended position.
[0082] Fig. 7 shows that the clamping jaw 30, consisting of the jaw parts of the base jaw 40 and the top jaw 60, which are now in a fixed relative position, can be displaced in radial direction 4 relative to the base 20. The seal 80 is also provided at the base 20, so that the movement of the clamping jaws 30 radially inwards and radially outwards represents a relative movement with respect to the seal. The sealing lip 82 of the seal 80 is adapted to an end face of the skirt 62 such that the sealing lip 82 bears against the end face all the way around, regardless of the position of the clamping jaw 30.
[0083] Figures 8 to 17 show a second embodiment of a clamping system 10 according to the present invention.
[0084] Similar to the first embodiment, the second clamping system 10 according to this embodiment is also designed in the form of a three-jaw chuck and has three clamping jaws 30 that can be displaced radially along arrows 4 and have inwardly projecting clamping areas 70 that are aligned in the direction of a central axis 2. Compared to the first clamping system of Fig.
[0085] This second clamping system differs from those in 1 to 7 in that it is better suited for use as an internal or external clamping device. Therefore, the outer surfaces of the clamping jaws 30 can also be used as a clamping area for internal contact with a workpiece.
[0086] Fig. 8 shows this second clamping system 10 in a partially cutaway view, from which it can again be seen that the clamping jaws 30 are each divided into two parts.
[0087] They have a base jaw 40, which, during the use of the clamping system 10, always remains attached to a base 20 of the clamping system and can be radially displaced by means of a common actuating element and a wedge gear. The clamping jaws 30 each also have a top jaw 60, which is designed to be easily and automatically interchangeable. These top jaws 60 provide the clamping areas 70, which, as designed, come into direct contact with the workpiece when it is clamped. Replacing the top jaws 60 also replaces the clamping area 70. Replacement may be necessary due to wear or to use a top jaw 60 that is particularly well adapted to the workpiece being machined in terms of its geometry or material. In particular, top jaws specifically designed for internal and external clamping can also be exchanged easily and quickly.
[0088] The base jaws 40 and the top jaws 60 are connected via a coupling system 120 in the form of a bayonet coupling system. Referring also to Figures 10 and 11, it can be seen that the base jaw 40 has a bayonet pin 144 extending parallel to the central axis. This pin has two opposing expansions 145 and a distal insertion end 148 with an insertion chamfer.
[0089] The outer surface of the bayonet pins 144 is shaped in a conical segment in the area of the expansions 145.
[0090] To receive the bayonet pin 144, a recess 164 is provided in the mounting jaw 60, which is surrounded by a skirt 172. The recess is bounded on two sides by radially inwardly projecting retaining sections 165. Between the retaining sections 165, the recess is widened in the area 167 and provided with a larger clear diameter to allow the insertion of the bayonet pin 144.
[0091] From the perspective of Fig. 11, the underside surfaces of the holding sections 165 are cone-shaped, corresponding to the widenings 145, so that a planar arrangement can be achieved in the coupled state.
[0092] Within the recess 164, an additional centering recess 168 is provided for receiving the distal inserter 148.
[0093] Referring to Fig. 10, movable retaining elements 182 are provided on the base 20 or, alternatively, on the base jaws 40. These retaining elements form part of an anti-rotation device 180 and provide stop surfaces to prevent the rotational movement of the coupled top jaw 60. Counter stops 186 are also part of this anti-rotation device 182. The retaining elements 182 can be pressed in parallel to the central axis 2 against the force of a return spring 184 (not shown). In a working position of the top jaws, as can be seen, for example, in Fig. 8, these retaining elements are not pressed in but are in a blocking position, in which they secure the locking of the top jaws 60.
[0094] To ensure correct coupling and locking of the top jaws 60, it is advantageous to largely prevent the ingress of contaminants and chips between the base jaw 40 and the top jaw. For this purpose, a circumferential seal 80 is provided on the base jaw 40, which rests against the skirt 172 all around when the top jaw 60 is correctly attached.
[0095] As can be seen in Fig. 10, support surfaces 150 are provided radially offset to the bayonet pin 144 on the inside and outside. These support surfaces serve the purpose of transferring part of the clamping force into the base jaw during clamping. This relieves the bayonet pin 144.
[0096] After the top jaw is attached, it comes into contact with the support surfaces. If a radial force is now introduced into the top jaw 60 at the inner or outer clamping area 70, this results in a moment acting on the top jaw 60, which is partially absorbed by the opposing support surfaces 150. Since the base jaw 40 can be used for both internal and external clamping, corresponding support surfaces 150 are provided on the inside and outside.
[0097] Figures 12A to 15B illustrate the process of coupling and locking.
[0098] In the initial state shown in Figures 12A and 12B, two top jaws 60 have already been attached and locked. This corresponds to the state shown in Figure 8. The two attached top jaws 60 are coupled and locked by means of the bayonet, which is formed by the bayonet pin 144 and the recesses 164, and the locking is secured by the anti-rotation devices 180 and the retaining elements 182 in their blocking position.
[0099] The third base jaw 40 does not yet have an extension jaw 60 attached.
[0100] Starting with the state shown in Figures 13A and 13B, the last top jaw 60 is fed in by means of a robot gripper 200, which is only shown schematically. The robot gripper 200 feeds the top jaw axially, rotated 90° relative to its eventual operating position. As shown in Figures 14A and 14B, it moves the top jaw 60 into an axial end position, which is reached when the bayonet pin 144 is engaged in the recess 164. Correct alignment is supported by the chamfer on the insertion end 148, which engages in the corresponding centering recess 168 of the top jaw 60.
[0101] When the top jaw is placed on the workpiece in the process of reaching the state shown in Figs. 14A, 14B, the retaining element 180 is pressed in. The pressure surface 170 on the underside of the top jaw 60 serves this purpose.
[0102] Starting from the intermediate state shown in Figures 14A and 14B, the robot gripper 200 rotates, and with it the top jaw 60. The jaw is rotated about the bayonet axis, which is parallel to the central axis 2, in the direction of its operating position. The retaining element 180 slides along the pressure surface until its edge is reached. As the top jaw 60 continues to rotate, the retaining element 180, still deflected against the force of the spring, continues to slide along the robot gripper 200. In the final state shown in Figures 15A and 15B, the top jaw 60 reaches its operating position and is locked by means of the bayonet coupling 120, but is not yet secured against rotation back from the locked position.
[0103] The robot gripper 200 is now opened, so that the gripping connection with the attachment jaw 60 is released. It is then moved upwards relative to the figures, thereby allowing the retaining element 180 of the last attachment jaw to assume its blocking position.
[0104] The last top jaw 60 is now attached to the clamping device and basically ready for clamping a workpiece, which is preferably supplied by another robot or another feeding mechanism.
[0105] As in the first embodiment, the clamping system of the second embodiment is also connected to a pneumatic testing system 90.
[0106] This pneumatic testing system 90 includes a pressure channel 92 that extends through the base 20 of the clamping system 10 and into the base jaw 40.
[0107] Figure 16 shows that the pressure channel 92 branches within the base jaw 40 and leads to two openings 94 on opposite sides of the bayonet pin 144. These openings are closed by the upper surfaces of the retaining sections 165 when the top jaw 60 is correctly fitted. Figure 17 shows that the pressure channel 92, or an independent second pressure channel 92, is provided in the base 20, leading to the retractable retaining element 182. In Figure 17, the retaining element 182 is in its locking position, in which it prevents the top jaw 60 from rotating backward. In this locking position, the retaining element largely closes the air outlet 96 at the end of the pressure channel 92.
[0108] If, on the other hand, the retaining element is in its position deflected against the force of the return spring 184 and not blocking the rotational movement of the top jaw, the air outlet 97 opens into a groove 188 on the retaining element 182, so that air can escape largely unhindered.
[0109] After the attachment jaws 60 are fitted, the pressure channel 92 is connected to a pressure source and a measuring device. Preferably, the two pressure channels on the base jaw 40 and on the base 20 are directly connected to each other so that a uniform pressure is established, provided that the openings 94 and the air outlet 96 are closed.
[0110] Provided that the expected dynamic pressure is established in the pressure channel 92 or that the volume flow is below an acceptable limit, it can be concluded that the openings 94 and the air outlet 96 are largely closed and, consequently, that the top jaw is in its intended position and the retaining element has assumed its blocking position.
Claims
Patent claims 1. Clamping system (10) for clamping workpieces with the following features: a. the clamping system (10) has a plurality of clamping jaws (30), preferably at least three clamping jaws (30), which are radially displaceable relative to each other and relative to a central axis of the base (20) of the clamping system, and b. the clamping jaws (30) each have a base jaw (40) which is movable relative to the base (20), and a top jaw (60) mounted on the base jaw (40) which can be changed automatically, on the outside of which a clamping area (70) is provided for contact with a workpiece to be clamped, characterized by the following additional feature: c. The clamping jaws (30) have a coupling system (120) for attaching the top jaw (60) to the base jaw (40), which includes corresponding positive locking elements (142, 162) which can be moved into a locked coupling position by a relative movement of the top jaw (60) relative to the base jaw (40), wherein the relative movement an axial insertion component for creating the coupling and a subsequent rotary locking component for positive locking in the axial direction exhibits.
2. Clamping system (10) according to claim 1 with the following further feature: a. the coupling system (120) is designed as a bayonet coupling system (120) 3. Clamping system (10) according to claim 1 or 2 with the following further feature: a. The clamping system (10) is designed as a clamping system (10) rotating about the central axis (2) for attachment to a rotary spindle of a machine tool.
4. Clamping system (10) according to claim 2 or 3 with the following further feature: a. The bayonet coupling system (120) has a bayonet pin (144) with a distal expansion (145) and a corresponding receiving contour (164) with radial retaining sections (165) which are provided for the positive locking of the expansion (145) introduced by relative rotation into the receiving contour (164), preferably with one of the following additional features: b. the bayonet pin (144) is provided on the base jaw (40) and the receiving contour (164) is provided on the top jaw (60), and / or c. a bayonet central axis (6) extends parallel to the central axis (2) of the base.
5. Clamping system (10) according to claim 4 with the following further feature: a. the bayonet pin (144) has a shape that widens continuously towards a distal end and holding sections (165) of the receiving contour (164) have correspondingly inclined holding surfaces.
6. Clamping system (10) according to one of the preceding claims with the following further feature: a. a rotation lock (180) is provided by means of which the rotational mobility of an attached top jaw is limited or completely prevented.
7. Clamping system (10) according to claim 6 with the following further feature: a. the anti-rotation device (180) comprises a movable retaining element (182) which can be moved between a non-blocking position and a blocking position, preferably with the following additional feature: b. A return spring (184) is associated with the retaining element (182), which exerts force on the retaining element (184) in the direction of the blocking position.
8. Clamping system (10) according to claim 7 with the following further feature: a. the movable retaining element (182) is designed as a retaining element (182) that can be pressed in towards the central axis (2), preferably with the following additional feature: b. the top jaw (60) has a pressure surface (170) for pressing down the retaining element (182).
9. Clamping system (10) according to one of the preceding claims with the following further feature: a. the attachment jaw (60) has a circumferential apron (172) that circumferentially surrounds the receiving contour (164).
10. Clamping system (10) according to one of the preceding claims with the following further feature: a. a seal (80) is provided which, when the top jaw (60) is placed on the base jaw (40), closes a gap between the top jaw (60) on the one hand and the base jaw (40) or the base (20) on the other hand, preferably with at least one of the following additional features: b. the seal (80) is designed as an elastic seal (80).
11. Clamping system (10) according to one of claims 4 to 10 with the following further feature: a. at least one support surface (150) is provided on the base jaw (40), spaced apart from the bayonet pin (144) and radially offset from the bayonet pin (144), on which the top jaw (60) is supported when a force is applied in the direction of the central axis (2) or in the direction away from the central axis (2), preferably with one of the following additional features: b. Support surfaces (150) are provided on the base jaw (40), spaced apart from the bayonet pin (144) and offset radially inwards and radially outwards from the bayonet pin (144), on which the top jaw (60) is supported when a force is applied in the direction of the central axis (2) and in the direction away from the central axis (2), and / or c. the radial distance between the bayonet central axis (6) and the support surface (150) is greater than the axial distance between a distal end of the bayonet pin (144) and the support surface (150).
12. Clamping system (10) for clamping workpieces with the following features: a. the clamping system (10) has a plurality of movable clamping jaws (30), preferably at least three clamping jaws (30), which are movable relative to each other and relative to a base (20) of the clamping system radially to the central axis, and b. the clamping jaws (30) each have a base jaw (40) which is movable relative to the base (20), and a top jaw (60) mounted on the base jaw (40) which can be changed automatically, on the outside of which a clamping area (70) is provided for contact with a workpiece to be clamped, characterized by the following additional features: c. the clamping system (10) has a pneumatic testing system (90) to check the correct positioning of the top jaw (60) on the base jaw (40), and d. the pneumatic testing system (90) has a pressure channel (92) in the base jaw (40) which can be subjected to overpressure or underpressure during the placement of the top jaw (60) and is closed at the end by a closing surface (68) of the top jaw (60) when correctly positioned.
13. Clamping system (10) according to claim 12 with the following further feature: a. The closing surface (68) of the top jaw (60) and the clamping area (70) of the top jaw (60) are aligned in opposite directions.
14. Clamping system (10) according to claim 12 or 13 with the following further feature: a. the pressure channel (92) opens into at least two openings (94) on the base jaw (40), which, when the top jaw (60) is correctly attached, are each at least largely closed by a closing surface of the top jaw.
15. Clamping system (10) according to one of claims 12 to 14 with the following further feature: a. the clamping system (10) comprised a movable holding element (182) which can be moved between a position that does not block the movement of the top jaw (60) relative to the base jaw (40) and a blocking position, and b. the pneumatic testing system (90) has an air outlet (96) which can be opened and at least largely closed by relocating the retaining element (182), preferably with the following additional feature: c. the retaining element (182) is operatively coupled to the air outlet (96) in such a way that when the retaining element (182) is arranged in its blocking position, the air outlet (96) is essentially closed.
16. Clamping system (10) according to one of the preceding claims with the following further feature: a. the clamping system (10) has a common actuating element (24) which, by displacing the actuating element in an axial direction, displaces the base jaws (40) radially against each other, preferably with the following additional feature: b. the radial displacement is achieved by means of a wedge drive (26).
17. Clamping system (10) according to one of the preceding claims with the following further feature: a. the clamping system (10) is designed as a three-jaw chuck or four-jaw chuck.