DE102014019712B4 - Tensioning device with a tie rod, connected to a piston by a bayonet lock - Google Patents

Abstract

Clamping device (1) for mechanically clamping a component (2), in particular a workpiece to be clamped, witha) an axially displaceable tie rod (10) for tensioning the component (2), andb) an axially displaceable piston (11) for displacing the tie rod (11) 10), characterized by c) a bayonet closure (17, 53) for releasably mechanically anchoring the tie rod (10) in the piston (11).

Description

The invention relates to a clamping device for clamping a component, in particular a workpiece to be machined.

From the prior art (eg DE 40 20 981 A1 . DE 20 2013 007 456 U1 . DE 10 2007 039 032 A1 . US 2006/0049568 A1 . US 2010/0327503 A1 ) clamping devices are known which have a pneumatically or hydraulically displaceable tie rod (clamping bolt), which can be introduced with its free end in a corresponding blind bore in the component to be clamped. The free end of the tie rod expands conically towards its end and is surrounded by a clamping bush, which is introduced together with the free end of the tie rod in the blind hole of the component to be clamped. Upon retraction of the tie rod, the clamping bush then initially remains in its position, so that the retraction of the tie rod due to the conical widening of the free end of the tie rod leads to a radial expansion of the clamping bush and thus to a clamping of the component. In a further retraction of the tie rod, the now stretched component can then perform a pull-down movement together with the tie rod and the clamping bush. In the known clamping devices of the type described above, the clamping of the component takes place by a frictional connection between the outer surface of the clamping bush and the inner circumferential surface of the blind bore in the component. A disadvantage of these known tensioning devices is the fact that the complete tensioning device must be dismantled to replace the tie rod.

Furthermore, it should be noted on the prior art DE 10 2004 025 256 A1 however, discloses a rotatable machine spindle with a chuck and thus relates to another object.

Out US Pat. No. 6,095,509 a tie rod is known, which is connected in a T-slot of a piston with this. To remove the tie rod here, however, further modifications to the clamping device are required.

Furthermore, it is off DE 20 2013 103 278 U1 a clamping device for workpieces with a bayonet lock known. However, this document does not relate to a tie rod nor a connected to the bayonet lock axially displaceable piston for moving the tie rod.

The invention is therefore based on the object to improve the initially described known clamping devices.

This object is achieved by an inventive clamping device according to the main claim.

The clamping device according to the invention initially has an axially displaceable tie rod (clamping bolt) for clamping the component, wherein the operation of such a tie rod is still described in detail.

Furthermore, the clamping device according to the invention comprises an axially displaceable piston for displacing the tie rod, wherein the piston can be driven, for example, hydraulically or pneumatically.

According to the invention, the tie rod is releasably anchored in the piston by a bayonet lock. This means that the tie rod can be inserted in a certain rotational position with respect to its longitudinal axis in the clamping device or removed therefrom. The anchoring of the tie rod then takes place in the inserted state by the tie rod is rotated about its longitudinal axis, for example by 90 °. An advantage of such a bayonet lock for the tie rod is the fact that no replacement of the tie rod is required to replace the tie rod. In addition, the tie rod can be replaced in this way directly on the jig. It should be mentioned here that the replacement of the tie rod can preferably take place without impairment of fluid lines (for example hydraulic lines) for driving the piston, so that there is no risk of hydraulic fluid escaping when replacing the tie rod.

In the preferred embodiment of such a bayonet closure, the tie rod has a hammer-shaped lateral extension at its lower end. In addition, the piston and the clamping device on an axial bore, through which the tie rod can be inserted. This axial bore is a slot in cross section, so that the tie rod can be inserted despite the hammer-shaped lateral extension.

Furthermore, it should be mentioned that in the bayonet closure preferably a first spring is provided, which biases the tie rod to avoid falling out of the tie rod from the tensioning device.

The invention also includes the general technical teaching to provide for clamping a positive connection between the outer surface of the clamping bush and the inner wall of the blind bore in the component to be clamped. An advantage of such a positive connection for clamping a component are the larger maximum clamping forces and the greater reliability of the positive connection.

In a variant of the invention, the positive connection between the clamping bush and the component consists of a threaded connection. Here, the outer surface of the clamping bush on an external thread which engages in a correspondingly adapted internal thread in the inner wall of the blind bore of the component and thereby produces the positive connection between the clamping bush and component.

In another variant of the invention, the positive connection between the clamping bush and component on the other hand by complementary profiling in the outer surface of the clamping bush on the one hand and in the inner wall of the blind bore of the component on the other hand. It is only important here that the profiling forms a positive connection between the clamping bush and the component in the axial direction.

In the previously described variant with a threaded connection between the clamping bush and the component, the external thread of the clamping bush and the internal thread of the component preferably have the same thread pitch in order to enable a positive threaded engagement.

It should be noted that the clamping bush can be widened in the radial direction as in the conventional clamping bush described above, wherein the clamping bush in the radially contracted state (relaxed state) does not form a positive connection with the component, whereas the clamping bush in the radially expanded state form fit into the Component engages.

Therefore, the external thread of the clamping bush in the radially contracted state usually has a smaller thread diameter than the internal thread of the bore, so that the clamping bush can then be introduced without problems in the blind bore in the component.

In the radially expanded state of the clamping bush, however, the external thread of the clamping bush preferably has the same thread diameter as the internal thread of the bore, so that external thread and internal thread then engage with each other and form the positive connection.

It should also be noted that the outside diameter of the external thread (i.e., tip to tip) of the collet in the radially contracted state of the collet is preferably smaller than the core diameter of the internal thread of the bore. This is useful so that the clamping bush can be introduced in the radially contracted state in the blind bore of the component.

The radially contracted condition is typically a relaxed state of the tensioner, i. without a radial widening by the tie rod. The radially expanded state of the clamping sleeve, however, is usually not the normal state of the clamping bush. Rather, the clamping bush takes on the radially expanded state only when the clamping bush is radially expanded by the tie rod.

In a preferred embodiment of the invention, the radial expansion of the clamping bush is made possible by a special construction. Here, the clamping bush has a plurality of segments which are distributed over the circumference of the clamping bush. The adjacent segments of the clamping bush are in each case separated from one another by an axially extending slot, wherein the individual slots each extend from the free end of the clamping bushing over at least part of the axial length of the clamping bush. This slotted arrangement allows the individual segments of the clamping bush to rebound in the radial direction to allow radial expansion of the clamping bush.

Furthermore, it should be mentioned that the clamping bush preferably has an axial through hole for the tie rod like the conventional clamping bush, wherein the through hole preferably expands radially towards the free end of the clamping bush, in particular in a conical shape. When retracting the tie rod then slide the conical surface of the tie rod on the one hand and the conical inner wall of the through hole on the other hand, which leads to a corresponding radial expansion of the clamping bush.

In a preferred embodiment of the clamping device according to the invention, the clamping device has a clamping bushing according to the invention, as described above, wherein the tie rod extends axially through the clamping bush and has at its free end a radial expansion, so that the tie rod when retracting the tie rod, the clamping sleeve radially expands. Here, the clamping bush thus - as described above - a positive connection between the clamping bush and the blind bore in the exciting part ago.

However, the invention is not limited to clamping devices with clamping bushes, which produce a positive connection to the component to be clamped. Rather, the invention also includes clamping devices with clamping bushes, in a conventional manner make a frictional connection to the blind bore in the component to be clamped. The invention is thus applicable to components with cylindrical blind holes, conical blind holes or blind holes with an internal thread.

It has already been mentioned briefly above that the piston and thus also the tie rod are preferably driven hydraulically or pneumatically. Therefore, the clamping device according to the invention preferably has two pressure chambers, namely a first pressure chamber for hydraulic or pneumatic pressurization of the piston for tensioning the tie rod and a second pressure chamber for hydraulic or pneumatic pressurization of the piston to relax the tie rod. The first pressure chamber for tensioning the tie rod is usually arranged above the piston and therefore presses the piston and thus also the tie rod preferably downwards. The second pressure chamber for relaxing the tie rod, however, is preferably disposed below the piston and therefore preferably pushes the piston to relax upwards.

In a preferred embodiment of the invention, the tensioning device has a so-called intrinsic safety device, which ensures that the component remains tensioned in the event of a pressure failure. For this purpose, a second spring may be provided, which biases the piston and thus also the tie rod in the clamping position. In general, the second spring pulls the piston and thus also the tie rod down, whereby the clamping bush is radially expanded and thereby produces a frictional and / or positive connection with the component to be clamped.

• - Bruch des Zugankers,
• - Bruch der Spannbuchse,
• - Auflage oder Abwesenheit eines Bauteils auf der Spannvorrichtung (Auflagekontrolle), sowie
• - axiale Stellung des Zugankers bzw. des Kolbens.
• - Vorrichtung entspannt (Zuganker und Kolben in entspannter Stellung).
• - Bohrung im Werkstück zu groß (Kolben fährt dann in die untere Stellung).

The tensioning device according to the invention preferably also comprises an interrogation device for interrogating the state of the tensioning device. For example, the interrogator may detect the following states of the chuck:

• - breakage of the tie rod,
• - breakage of the clamping bush,
• - Placement or absence of a component on the clamping device (support control), as well
• - axial position of the tie rod or the piston.
• - Device relaxed (tie rod and piston in a relaxed position).
• - Hole in the workpiece too large (piston then moves to the lower position).

In the preferred embodiment of the invention, such an interrogator operates pneumatically. For this purpose, the interrogator can blow out compressed air from the bearing surface of the clamping device. With a support of a component on the support surface, the component then blocks the outlet opening, which manifests itself in a corresponding change of pressure and flow and thus can be detected metrologically.

In addition, the compressed air from the interrogator can also be introduced into the cylinder, in which the piston is displaceable. This allows a detection of the piston position, since the piston can release the bore, for example, in the maximum tensioned state or a fracture of the tie rod, which in turn manifests itself in a corresponding change of pressure or flow of compressed air and thus can be detected metrologically.

Furthermore, the tensioning device according to the invention preferably comprises a blocking air device for blowing out sealing air in the region of a support around the free end of the tie rod. The sealing air should ensure that the contact area of the clamping device remains clean.

In addition, the compressed air from the blocking air device can also be introduced into the cylinder, in which the piston is displaceable. In a relaxed position, the pressure in this line increases through the existing throttle. This allows a query of the relaxation position. The workpiece can thus be removed from the device. In the cocked position, the air also passes through the holes 48 and 52 (see. 4 and 5 ) with a larger volume (pressure difference is measurable).

In addition, the clamping device according to the invention preferably has an elastic centering element in order to effect a pre-centering of the tie rod in the tensioning device. In the preferred embodiment of the invention, the centering element is an elastic O-ring, which surrounds the tie rod in an annular manner, so that a radial deflection of the tie rod leads to a centering counterforce through the 0-ring. In one variant of the invention, the centering element (for example O-ring) is arranged below the clamping bush and surrounds only the tie rod, wherein the centering element bears directly against the lateral surface of the tie rod. In contrast, in another variant of the invention, the centering element (for example, O-ring) surrounds both the tie rod and the surrounding clamping bush so that the centering element bears against the clamping bush on the outside.

It should also be mentioned that the tensioning device according to the invention can preferably perform two axial movements, namely on the one hand a tensioning movement and on the other hand a Niederzugsbewegung. The clamping movement serves exclusively to radially expand the clamping bush and thereby produce a frictional or positive connection between the clamping bush and the component to be clamped. By contrast, during the clamping movement, the component to be clamped is not yet moved itself. After tensioning of the component by the clamping movement then takes place, however, an axial pull-down movement, wherein the now-tensioned component is pulled axially against the clamping device to adjust a defined position of the component. To allow such a pull-down movement, the clamping bushing in the clamping device is preferably mounted with an axial clearance, so that the clamping bushing can perform the axial down movement together with the tensioned component.

Preferably, in this case, a third spring is provided for biasing the clamping bush against the pull-down movement. The third spring thus presses the clamping bush upward, so that the tie rod must overcome the spring force of the third spring in the pull-down movement. The third spring ensures during the previous tensioning movement of the tie rod that the clamping bush does not yield axially, but is radially expanded. On the one hand, the third spring thus provides sufficient resistance so that the clamping bush does not yield axially when the tie rod is pulled down, but widens radially. On the other hand, however, the third spring is so yielding that the expanded clamping bushing can perform a down movement together with the tensioned component.

In one embodiment of the invention, the clamping bush has a radially projecting collar at the bottom, the third spring surrounding the radially projecting collar on the outside and pressing radially inward. The force acting on the radially projecting collar and inwardly directed clamping force is then converted into the clamping bushing in a corresponding axially directed force, which presses the clamping sleeve upwards.

In another embodiment, however, the third spring is arranged under the clamping bush and presses the clamping sleeve axially upwards.

In an advantageous variant of the invention, the clamping bush on its underside on a conical ramp surface, which tapers conically upwards. The clamping bush lies here with its conical ramp surface on a fixed in the clamping device and complementary inclined conical ramp surface. The sliding together of the conical ramp surfaces then leads in a clamping operation to a radial expansion of the clamping bush and then during the pull-down movement also to an axial downward movement.

• 1A eine aufgeschnittene Perspektivansicht einer erfindungsgemäßen Spannvorrichtung,
• 1B eine Detailansicht des Bajonettverschlusses der Spannvorrichtung aus 1A,
• 2 eine Querschnittsansicht der Spannvorrichtung aus den 1A und 1B zur Verdeutlichung der Druckbeaufschlagung des Kolbens beim Spannen,
• 3 eine andere Querschnittsansicht der Spannvorrichtung aus den 1A und 1B zur Verdeutlichung der Druckbeaufschlagung des Kolbens beim Entspannen,
• 4 eine weitere Querschnittsansicht der Spannvorrichtung aus den 1A und 1B zur Verdeutlichung des Ausblasens von Sperrluft aus der Spannvorrichtung und zur Erläuterung einer Abfrage der Entspann-Stellung mit einer Drossel (Meldung: Werkstück kann entnommen werden),
• 5 eine weitere Querschnittsansicht durch die Spannvorrichtung aus den 1A und 1B zur Verdeutlichung einer pneumatischen Abfrageeinrichtung,
• 6 eine vergrößerte Detailansicht aus 2 zur Verdeutlichung des axialen Spiels der Spannbuchse als Voraussetzung für eine Niederzugsbewegung,
• 7 eine vergrößerte Detailansicht in axialer Richtung auf dem eingerasteten Spannbolzen des Bajonettverschlusses,
• 8 eine Querschnittsansicht zur Verdeutlichung des Bajonettverschlusses für den Zuganker,
• 9 eine Abwandlung des Ausführungsbeispiels gemäß den 1A bis 8 mit einer zusätzlichen Feder zur Eigensicherung, sowie
• 10 eine Abwandlung mit einer konischen Auflauffläche an der Spannbuchse zur radialen Aufweitung der Spannbuchse.
• 11 eine Abwandlung mit einem elastischen Ring zur Erleichterung des Einfügens des Gewindes.
• 12 eine Abwandlung mit einem Luftpolster zur Erleichterung des Einfügens des Gewindes.

Other advantageous developments of the invention are characterized in the subclaims or are explained in more detail below together with the description of the preferred embodiments of the invention with reference to FIGS. Show it:

• 1A a cutaway perspective view of a clamping device according to the invention,
• 1B a detailed view of the bayonet lock of the clamping device 1A .
• 2 a cross-sectional view of the clamping device of the 1A and 1B to illustrate the pressurization of the piston during clamping,
• 3 another cross-sectional view of the clamping device of the 1A and 1B to illustrate the pressurization of the piston when relaxing,
• 4 another cross-sectional view of the clamping device of the 1A and 1B to clarify the blow-out of sealing air from the clamping device and to explain a query the relaxation position with a throttle (message: workpiece can be removed),
• 5 another cross-sectional view through the clamping device of the 1A and 1B to illustrate a pneumatic interrogator,
• 6 an enlarged detail view 2 to illustrate the axial play of the clamping bush as a prerequisite for a pull-down movement,
• 7 an enlarged detail view in the axial direction on the latched clamping bolt of the bayonet closure,
• 8th a cross-sectional view to illustrate the bayonet lock for the tie rod,
• 9 a modification of the embodiment according to the 1A to 8th with an additional spring for intrinsic safety, as well
• 10 a modification with a conical ramp surface on the clamping bush for radial expansion of the clamping bush.
• 11 a modification with an elastic ring to facilitate the insertion of the thread.
• 12 a modification with an air cushion to facilitate the insertion of the thread.

The 1A to 8th show different views of a tensioning device according to the invention 1 for clamping a component 2 , where the component 2 only in 2 is shown schematically and is omitted otherwise for the sake of clarity. The component 2 indicates engagement by the tensioning device 1 a blind hole 3 with an inner wall 4 on that with an internal thread 5 is provided to allow a positive engagement, as will be described in detail.

The tensioning device 1 has a housing 6 on top by a case lid 7 and below through a caseback 8th is closed. The annular gap between the housing bottom 8th and the housing 6 is here by a seal 9 sealed.

In the tensioning device 1 is a tie rod 10 arranged axially displaceable, wherein the tie rod 10 from a likewise axially displaceable piston 11 can be moved, as also described in detail. The annular gap between the outer surface of the piston 11 and the inner wall of the housing 6 This is due to two seals 12 . 13 sealed.

The piston 11 has an axial through hole 14 on, through which the lower end of the tie rod 10 passed through, the tie rod 10 in the piston 11 is anchored by a detachable bayonet lock, as will be described in detail.

In the pistons 11 Below is a piston insert 15 inserted, being at the bottom of the piston insert 15 a feather 16 supports the tie rod 10 pushes axially upward so that the bayonet lock of the tie rod 10 does not accidentally release.

The through hole 14 in the piston 11 is here executed in cross section as a slot, as from 7 is apparent. The tie rod 10 has at its lower end a hammer-shaped lateral extension 17 on, which in the anchored state of the bayonet lock down to projections 53 in the piston 11 supported. In a certain angular position of the tie rod 10 So just in the jig 1 be introduced because the trained as a slot through hole 14 then offers enough space. After inserting the tie rod 10 becomes the tie rod 10 then turned 90 °, whereupon the tie rod 10 with its hammer-shaped extension 17 on the piston 11 supported.

However, other variants are possible, such as attachment e.g. via swivel cam or stop bolt.

The feather 16 prevents the tie rod from becoming damaged 10 unintentionally turns and then out of the jig 1 could fall out (click into the projection 53 ).

In addition, the tensioning device points 1 in the upper part an inner part 18 on, that's the tie rod 10 annular surrounds and includes a through hole in which an O-ring 19 for pre-centering of the tie rod 10 is arranged. With a lateral deflection of the tie rod 10 namely exerts the O-ring 19 namely an inwardly directed counterforce, causing the tie rod 10 in the tensioning device 1 is centered.

The inner part 18 relies on a compression spring 20 on the housing 6 from. The compression spring 20 pushes the inner part 18 So up.

The free end of the tie rod 10 is from a clamping bush 21 surrounded, with the clamping bush 21 during clamping of the component 2 in the blind hole 3 is introduced and then produces a positive connection. For this purpose, the clamping bush 21 on its outer lateral surface on an external thread, which is connected to the internal thread 5 the blind hole 3 is adjusted.

The free end of the tie rod 10 has an outer surface that extends to the end of the tie rod 10 conically (alternatively also pyramid surfaces are possible) extended. Accordingly, also the clamping bush 21 a conical inner wall which widens conically towards the free end. A retraction of the tie rod 10 in the tensioning device 1 It therefore leads due to the successive sliding conical surfaces of the tie rod 10 on the one hand and the clamping bush 21 on the other hand, that the clamping bush 21 radially expands. The external thread of the clamping bush 21 then accesses the correspondingly adapted internal thread 5 the blind hole 3 and thereby establishes a positive connection.

Furthermore, it should be mentioned that the clamping bush 21 outside of an annular scraper 22 is surrounded. The scraper 22 prevents dirt from entering the clamping device 1 can penetrate.

2 shows a cross-sectional view of the clamping device 1 with a hydraulic connection 23 for tensioning the tie rod 10 , The hydraulic connection 23 is over oil channels 24 . 25 with a pressure room 26 connected, wherein in the pressure chamber 26 acting hydraulic pressure from above on the piston 11 pushes and the piston 11 if necessary press down. The piston 11 then take the tie rod 10 accordingly down with. Furthermore, it should be mentioned that the oil channel 25 at its top by a stopper 27 is closed.

3 shows another cross-sectional view of the clamping device of the 1A and 1B with a hydraulic connection 28 for releasing the tensioning device 1 , The hydraulic connection 28 is over oil channels 29 . 30 with a pressure room 31 connected, wherein in the pressure chamber 31 prevailing oil pressure from below on the piston 11 acts and the piston 11 by pushing upwards. It should be mentioned that the oil channel 30 at its top also by a plug 32 is closed.

4 shows a further cross-sectional view of the clamping device 1 with another pneumatic connection 33 for a blocking air device and a query of the release position of the piston ( 11 ). The pneumatic connection 33 is via compressed air channels 34 . 35 . 36 . 48 with a pressure room 37 in the housing cover 7 connected, from where the compressed air can be blown up through blow-out to the support area of the clamping device 1 to keep clean. It should be mentioned that the compressed air channel 34 outside through a stopper 38 is closed.

A throttle 49 ensures a pressure difference. In the relaxed state is the piston 11 in its upper position and the compressed air channel 48 (Barrier air channel) closed, ie there is a pressure difference between cocked and relaxed position.

5 shows yet another cross-sectional view of the clamping device 1 with another pneumatic connection 39 for a pneumatically operated interrogator.

The pneumatic connection 39 the interrogator opens on the one hand via a compressed air channel 40 in the cylinder in which the piston 11 is axially displaceable. In this way, the position of the piston 11 be queried by the interrogator, since the pressure conditions at the pneumatic port 39 change when the piston 11 the mouth of the compressed air channel 40 releases.

On the other hand opens the pneumatic connection 39 the interrogator but also via compressed air channels 41 . 42 in a run control hole 43 in the tensioned state of the component 2 is closed, causing the pressure conditions at the pneumatic connection 39 change what can be measured metrologically and thus allows a run control.

The functioning of the tensioning device according to the invention will now be described below 1 described.

It is assumed that the tie rod 10 already in the tensioning device 1 mounted and anchored by means of the bayonet closure. The feather 16 pushes the tie rod 10 then up against the piston 11 and prevents thereby that the bayonet lock, for example, dissolves in vibration or vibration, which in the worst case to a falling out of the tie rod 10 could lead (snapping on the projection 53 ).

The tensioning device 1 is then initially relaxed by passing through the hydraulic connection 28 Oil is supplied, which is then in the pressure chamber 31 from below on the piston 11 Acts and the piston together with the tie rod 10 pushes up. During this relaxation of the tensioning device is the hydraulic connection 23 depressurized.

Then then the component 2 be placed so that the free end of the tie rod 10 with the clamping bush 21 in the blind hole 3 is introduced.

It should be mentioned that the clamping bush 21 in the relaxed state has an outer diameter which is smaller than the inner diameter of the inner wall 4 the blind hole 3 , This is important to allow the tie rod 10 with the clamping bush 21 in the relaxed state in the blind hole 3 can be introduced.

After placing the component 2 on the tensioning device 1 closes the component 2 the pad control hole 43 at the top of the jig 1 , what at the pneumatics connection 39 is measurable.

Then the clamping device 1 then excited. For this purpose, first the hydraulic connection 28 depressurized. In addition, the hydraulic connection 23 controlled so that the oil pressure in the pressure chamber 26 the piston 11 together with the tie rod 10 pulls down. During this downward movement of the tie rod 10 slide the conical surfaces of the tie rod 10 and the clamping bush 21 on top of each other, resulting in a radial expansion of the clamping bush 21 leads. In this radial expansion of the clamping bush 21 engages the external thread in the lateral surface of the clamping bush 21 then into the internal thread 5 in the inner wall 4 the blind hole 3 and thus provides a positive connection between the clamping bush 21 and the component 2 ago.

In a further downward movement of the tie rod 10 leads the now form-fitting tensioned component 2 then a pull-down motion to the component 2 firmly to the bearing surface of the clamping device 1 to draw. It should be mentioned that the clamping bush 21 with its underside on the inner part 18 rests. Another pull down of the tie rod 10 So leads to a corresponding downward movement of the clamping bush 21 and thus also of the inner part 18 , which is supported on the compression spring 20. The pull-down motion must therefore be the counterforce of the compression spring 20 overcome.

The interrogator can then by polling the pressure conditions at the pneumatic connection 39 determine if the component 2 firmly on the bearing surface of the clamping device 1 is pulled, whereupon the clamping operation is then completed.

Out 6 it can be seen that the inner part 18 and thus also the clamping bush 21 in the tensioning device 1 with an axial play a is stored after the clamping of the component 2 to allow the pull-down movement.

9 shows a modification of the embodiment described above, this embodiment is largely consistent with the embodiment described above, so that reference is made to avoid repetition of the above description, the same reference numerals are used for corresponding details.

A special feature of this embodiment is that the clamping device 1 has a so-called intrinsic safety. This means that the component 2 remains tense even with a pressure loss. This is an additional spring 44 provided the piston 11 and thus also the tie rod 10 pulls down into the clamping position.

Finally shows 10 a further modification, which also largely coincides with the embodiments described above, so reference is made to avoid repetition of the above description, wherein the same reference numerals are used for corresponding details.

A special feature of this embodiment is that the clamping bush 21 on its underside a radially protruding collar 45 has and a conical ramp surface 46 laying on a conical casserole 47 the tensioning device can slide. In the case of the pull-down movement, therefore, the conical ramp surfaces slide 46 . 47 on top of each other, leaving the radially protruding collar 45 against the radially directed counterforce of the compression spring 20 evades to the outside, which allows the pull-down movement.

The 11 and 12 show variations that are largely consistent with the embodiments described above, so reference is made to avoid repetition of the above description, wherein the same reference numerals are used for corresponding details.

The peculiarity of 11 is that the clamping bush 21 on the bottom of an elastic ring 50 rests, making the insertion of the thread of the clamping bush 21 is relieved.

The peculiarity of 12 is that the clamping bush 21 on the bottom of an elastic ring 50 Floating, which also inserts the thread of the clamping bush 21 is relieved.

LIST OF REFERENCE NUMBERS

1

jig

2

component

3

blind hole

4

Inner wall of the blind hole

5

Internal thread of the blind hole

6

Housing of the clamping device

7

housing cover

8th

caseback

9

Seal between housing bottom and housing

10

tie rods

11

piston

12

Seal between piston and housing

13

Seal between piston and housing

14

Through hole in the piston

15

spool insert

16

Spring for prestressing the tie rod

17

Hammer-shaped extension of the tie rod

18

inner part

19

O-ring for pre-centering the tie rod

20

Compression spring for biasing the clamping bush against the pull-down movement

21

clamping bush

22

scraper

23

Hydraulic connection for tensioning the tie rod

24

Oil channel for tensioning the tie rod

25

Oil channel for tensioning the tie rod

26

Pressure chamber for tensioning the tie rod

27

Plug

28

Hydraulic connection for relaxing the tie rod

29

Oil channel to relax the tie rod

30

Oil channel to relax the tie rod

31

Pressure chamber for relaxing the tie rod

32

Plug

33

Pneumatic connection for blocking air device

34

Compressed air channel of the blocking air device

35

Compressed air channel of the blocking air device

36

Compressed air channel of the blocking air device

37

Pressure chamber of the blocking air device

38

Plug

39

Pneumatic connection of the interrogator

40

Compressed air channel of the interrogator (piston position control)

41

Compressed air channel of the interrogator

42

Compressed air channel of the interrogator

43

Support control bore

44

Spring for intrinsic safety in case of pressure failure

45

Collar of the clamping bush

46

Bearing surface of the clamping bush

47

Stationary ramp surface

48

Compressed air channel query release position

49

Restrictor / orifice

50

Elastic ring for height compensation

51

Bore to create the air cushion

52

Compressed air duct for pressure difference measurement

53

Projection for bayonet catch (hammer of the tie rod)

a

Axial play of the clamping bush and the inner part

Claims (13)

Clamping device (1) for the mechanical clamping of a component (2), in particular a workpiece to be clamped, with a) an axially displaceable tie rod (10) for clamping the component (2), and b) an axially displaceable piston (11) for displacing the Tie rod (10), characterized by c) a bayonet closure (17, 53) for the releasable mechanical anchoring of the tie rod (10) in the piston (11). Clamping device (1) after Claim 1 , characterized by a clamping bush (21) for clamping in a bore (3) of the component (2), a) wherein the clamping bush (21) is radially contracted in a relaxed state, so that the clamping bush (21) into the bore (3 ) and can be pulled out of the bore (3), b) whereas the clamping bush (21) is radially expanded in a tensioned state, so that the lateral surface of the clamping bush (21) has a mechanical connection with the inner wall of the bore (3). forms, c) wherein the mechanical connection between the lateral surface of the clamping bush (21) and the inner wall of the bore (3) is positively. Clamping device (1) after Claim 1 or 2 , characterized by a) an external thread in the lateral surface of the clamping bush (21) to engage in an internal thread (5) in the inner wall (4) of the bore (3) and thereby produce the positive connection, or b) a profiling in the lateral surface the clamping bush (21) to engage in a corresponding profiling in the inner wall of the bore (3) and thereby produce the positive connection. Clamping device (1) after Claim 3 , characterized in that a) that the external thread of the clamping bush (21) and the internal thread (5) of the bore (3) have the same thread pitch, and / or b) that the external thread of the clamping bush (21) in the radially contracted state has a smaller thread diameter as the internal thread (5) of the bore (3), and / or c) that the external thread of the clamping bush (21) in the radially expanded state has the same thread diameter as the internal thread (5) of the bore (3), and / or d) that in the radially contracted state of the clamping bush (21) of the outer diameter of the external thread of the clamping bush (21) is smaller than the core diameter of the internal thread (5) of the bore (3). Clamping device (1) according to one of the preceding claims, characterized in that a) that the clamping bush (21) distributed over the circumference of the clamping bush (21) has a plurality of segments, b) that the adjacent segments are each separated by an axially extending slot, and c) that the individual slots originate from the free end of the clamping bush (21) and at least extend over part of the axial length of the clamping bush (21). Clamping device (1) according to one of the preceding claims, characterized in that a) that the clamping bush (21) has an axial through hole for a tie rod (10), and b) that the through hole to the free end of the clamping bush (21) radially extended, in particular conical, or c) that the through hole to the free end of the clamping bush (21) towards pyramid-shaped merges into a plurality of chamfers. Clamping device (1) according to one of the preceding claims, characterized in that a) that the tie rod (10) through the bayonet closure (17, 53) is interchangeable without opening the fluid lines to drive the piston (11), and / or b) that the tie rod (10) has at its lower end a hammer-shaped lateral extension (17), and / or c) that the piston (11) for the passage of the tie rod (10) has an axial bore (14) which is a slot in cross-section such that the hammer-shaped enlargement (17) of the tie rod (10) can be performed in a certain angular position of the tie rod (10) through the axial bore (14) and otherwise causes a positive anchoring of the tie rod (10) in the piston (11) and / or d) that the tie rod (10) by a first spring (16) is biased against the piston (11) to prevent falling out of the tie rod (10). Clamping device (1) according to one of the preceding claims, characterized by a) a first pressure chamber (26) for hydraulic or pneumatic pressurization of the piston (11) for tensioning the tie rod (10), and / or b) a second pressure chamber (31) for hydraulic or pneumatic pressurization of the piston (11) to relax the tie rod (10), and / or c) a second spring (44), which biases the piston (11) in a clamping position, so that the component (2) without a Pressurization is maintained. Clamping device (1) according to one of the preceding claims, characterized by an interrogation device for interrogating the state of the clamping device (1), in particular for detecting the following states: a) breakage of the tie rod (10), b) breakage of the clamping bush (21), c ) Placement or absence of a component (2) on the tensioning device (1), d) Position of the tie rod (10) and / or the piston (11) in the relaxed position (48). e) Hole in the workpiece too large (40). Clamping device (1) according to one of the preceding claims, characterized by a blocking air device for blowing out sealing air in the region of a support around the free end of the tie rod (10) around. Clamping device (1) according to one of the preceding claims, characterized in that a) that the tensioning device (1) for pre-centering the tie rod (10) has an elastic centering element (19), in particular in the form of a tie rod (10) surrounding O-ring ( 19), and / or b) that centering element (19) annularly surrounds the clamping bush (21) and the tie rod (10), or c) that the centering element (19) annularly surrounds the tie rod (10) and below the clamping bush (21) is arranged. Clamping device (1) according to one of the preceding claims, characterized in that a) that the clamping bush (21) in the clamping device (1) with an axial clearance (a) is mounted so that the clamping bush (21) can perform an axial down movement, and / or b) that a third spring (20) is provided for biasing the clamping bush (21) against the pull-down movement. Clamping device (1) after Claim 12 , characterized in that a) that the clamping bushing (21) below a radially projecting collar (45) and the third spring (20) surrounds the radially projecting collar (45) outside and radially inwardly presses, or b) that the third spring (20) is arranged under the clamping bush (21) and the clamping bush (21) presses axially upwards.

Images