EP1531027A1 - Clamping device and method of clamping of workpieces, tools, molds or devices - Google Patents

Abstract

The clamping element clamps workpieces (46) etc. on machine tables (47) or pallets. It includes a positioner (22) and a clamping piece (33). During the movement of the positioner, the clamping piece is a lot, so that it can only be operated at the end of the movement of the positioner. The clamping piece may have a compression spring (41) and a return bolt (40).

Description

The invention relates to a clamping element for clamping workpieces, Tools, molds or devices on machine tables or pallets, with a movable positioning means and a movable on the positioning means guided clamping piece. Furthermore, the invention relates to a method for Clamping workpieces, tools or devices with such Clamping element.

Such clamping elements are z. B. Linearspanner, as described in DE 37 33 676 A1 disclosed, or swing clamps, for example, according to DE 101 27 214 A1.

The well-known from DE 37 33 676 A1 linear clamp has a linear over a to exciting workpiece movable positioning, namely a hydraulic actuated piston. This piston carries at its free end the clamping piece, which is connected via wedge surfaces movable with the piston. When extending of the piston, the clamping piece is driven against a stop. Then the Piston further moved over the clamping piece, so that the clamping piece moved due to the wedge surfaces transversely to the piston and against the exciting Workpiece or the like is pressed. The clamping element develops a Transverse force depending on the force acting on the piston and the angle of the Wedge surface over which this force on the clamping piece and thus on the workpiece or the like is transmitted. At the same time, in response to the clamping force the piston pushed away from the workpiece, so that a bending moment and a Transverse force on the piston while it is still extended. The The consequence is that the friction between the piston and the housing bore, in which the piston is guided increases. At the same time reduced due to the friction of the piston the clamping force as a function of the piston length. This Problem is exacerbated even with linear tensioners with wide expansive Clamping point, so with a large piston length and correspondingly large distance between the housing and the clamping piece in the clamping position.

The same disadvantages occur analogously with swing clamps. The Indian DE 101 27 214 A1 shown pivoting has as positioning a in a housing pivotally mounted and retractable mounted, hydraulically actuated swivel piston. During a first part of the Einfahrhubes is the oscillating piston, controlled by spiral grooves on the oscillating piston, in the Pivoted clamping position. Then the piston is over the remainder of the stroke retracted linearly and thereby the workpiece by means of a swivel piston attached clamping iron, on which the clamping piece is attached, tense. Again, occur during the clamping movement in the clamping arm and in Swivel piston bending moments and shear forces, through which the with the Clamps firmly connected rotary piston in its housing bearing bore generated during its axial movement by tilting increased bearing friction which increases proportionally with each extension of the Spanneisenhebelarms and the Clamping force greatly reduced.

The invention is based on the problem, a clamping element and a method to create, in which, does not affect the size of the generated clamping force unfavorable is the length of a clamp or a positioning means on this acting lateral forces and bending moments.

To solve this problem, the clamping element according to the invention is characterized characterized in that the clamping piece during the movement of the positioning means is locked, such that it is only at the end of the movement of the positioning is operable. The inventive method is characterized in that the clamping piece is actuated only at the end of the movement of the positioning means.

The invention thus ensures that the piston is completely complete extended or the swing piston is completely pivoted. Only at; only when Standstill of the (swing) piston in the end position, the clamping piece is actuated and against the workpiece or the like for clamping the same driven. Only in this moment occur lateral forces and a bending moment on the (swing) piston on. The (swing) piston is then already quiet, so that it no longer to a increased friction comes. Since the clamping piece is operated separately, is the Clamping force independent of the overhang of the clamping point freely selectable.

After a constructive development of the invention is suitable for locking or locking the clamping piece during the movement of the positioning means especially a return bolt. This is preferably by a compression spring in biased its locking position, so that is always the basic position biased position results. In case of failure of the pressure medium supply is ensured that the clamping piece is locked. The return bolt itself engages a development of the invention in a recess in the clamping piece. there the recess may have a bulge, so that for releasing the Return bolt from the locking position required compressive force is increased and so the certainty that the return bolt is not unintentional from the locked position escapes, is still enlarged.

Furthermore, the recess may be provided with a slope so that Actuate the return bolt in the direction of the clamping piece the clamping piece is retracted. This is a separate actuating means for the Clamp in the retraction of the same superfluous. The return bolt itself is included preferably pressure-medium-actuated.

Pressure chambers for the clamping piece and for the return bolt correspond preferably with pressure chambers for actuating the positioning in the one or each other direction. This allows the entire clamping element with only two Pressure medium connections, a connection for clamping and a connection to the Loosen, be supplied.

In a cylindrical positioning means can be inclined positions of Realize clamping piece in which the positioning means is rotated about its longitudinal axis becomes. However, the positioning should but in its respective inclination be fixed. For this purpose, it is preferably provided that the positioning means for one a hole for receiving the return bolt and the other one further bore with a widening to accommodate a positioning pin having. At least this hole is off-center and serves to over the Positioning pin to fix the angular position of the positioning. At a Further development of this idea of the invention is the bore for receiving the Positioning pin at the same time a pressure medium channel for connecting the pressure chamber for the clamping piece with the pressure space for the positioning means. separate Holes are thereby avoided. To release the channel that should Positioning agent thereby be provided with a flattening. Furthermore, it is possible to provide the positioning only in a widening of this hole. Outside the area of the positioning pin, the bore can be made narrower.

The positioning means itself can be formed in one piece, in which case it frontally so to speak from the rear, so of the later clamping piece turned away side is inserted into its housing. Then it will be still screwed a socket for receiving the clamping piece and the Inserted clamping piece. Alternatively, it is also possible that positioning form two parts, namely with a screwed-on piston ring. In this Case, the positioning means from the other side, that of the later Inserted end face turned into its housing and then from screwed on the other side of the piston ring. This variant is something more expensive, but offers the advantage of providing larger strokes for the clamping piece too can.

Some embodiments of the invention are as so-called swing clamps educated. In this case, a pivoting movement of the swing clamp on a Axialhub a reciprocating executed on which a clamping iron, the present case corresponds to the positioning, is attached. The clamping iron So also performs a height movement. For some Embodiments of the invention, however, is provided, one in his Provide longitudinal axis immovable swivel mast. This is rotatable clamped between a swivel base and a pivot bushing. Within the swivel base and the swivel mast are frontally to each other arranged corresponding holes in which a pivoting piston slidably arranged. This has the usual spiral groove over which the Pivoting movement is generated. About a longitudinal groove and a so cooperating gear means, in particular a pin or a ball is transmit this pivoting movement on the pivot mast. Such a Swing clamp builds flat. The required clamping movement is alone by achieved the lowering of the clamping piece.

Another alternative of an even flatter swing clamp provides, a arranged quasi lying, so transversely to the longitudinal direction of the swivel mast slidably disposed pivot piston provide. This one has his turn a gear member, in particular a trapezoidal groove, with a on the lower end face of the swivel mast arranged corresponding Gear member, in particular a pin cooperates. Through the back and forth The movement of the thrust piston is then via the trapezoidal groove and the pin Pivoting movement of the swivel mast generated.

Fig. 1

ein erstes Spannelement mit den Erfindungsmerkmalen im Längsschnitt,

Fig. 2

das Spannelement gemäß Fig. 1 in Draufsicht,

Fig. 3

das Spannelement gemäß Fig. 1 in Vorderansicht,

Fig. 4

eine Befestigungsvariante des Spannelementes gemäß Fig. 1 im Längsschnitt,

Fig. 5

ein zweites Spannelement mit den Erfindungsmerkmalen im Längsschnitt,

Fig. 6

das Spannelement gemäß Fig. 5 in Draufsicht,

Fig. 7

das Spannelement gemäß Fig. 5 in Rückansicht,

Fig. 8

das Spannelement gemäß Fig. 5 in Vorderansicht,

Fig. 9

ein drittes Spannelement mit den Erfindungsmerkmalen im Längsschnitt,

Fig. 10

ein viertes Spannelement mit den Erfindungsmerkmalen im Längsschnitt,

Fig. 11

das Spannelement gemäß Fig. 10 im Teilschnitt in der Ebene XI - XI,

Fig. 12

das Spannelement gemäß Fig. 10 im Teilschnitt in der Ebene XII,

Fig.13

ein weiteres Spannelement mit den Erfindungsmerkmalen im Längsschnitt,

Fig. 14

das Spannelement gemäß Fig. 13 in Draufsicht, teilweise geschnitten,

Fig. 15

das Spannelement gemäß Fig. 13 im Schnitt in der Ebene XV - XV gemäß Fig. 14.

The invention will be explained below with reference to some illustrated in the drawings embodiments. Show it:

Fig. 1

a first clamping element with the inventive features in longitudinal section,

Fig. 2

the clamping element of FIG. 1 in plan view,

Fig. 3

the tensioning element according to FIG. 1 in front view,

Fig. 4

a fastening variant of the clamping element of FIG. 1 in longitudinal section,

Fig. 5

a second clamping element with the inventive features in longitudinal section,

Fig. 6

the tensioning element according to FIG. 5 in plan view,

Fig. 7

the tensioning element according to FIG. 5 in rear view,

Fig. 8

the tensioning element according to FIG. 5 in front view,

Fig. 9

a third clamping element with the inventive features in longitudinal section,

Fig. 10

a fourth clamping element with the inventive features in longitudinal section,

Fig. 11

10 in partial section in the plane XI - XI,

Fig. 12

the clamping element according to FIG. 10 in a partial section in the plane XII,

Figure 13

another clamping element with the features of the invention in longitudinal section,

Fig. 14

the clamping element according to FIG. 13 in plan view, partially cut,

Fig. 15

the clamping element according to FIG. 13 in section in the plane XV - XV according to FIG. 14.

The tensioning element shown in FIGS. 1 to 4, namely linear tensioner 20, has a guided in a housing 21 piston rod 22 as a positioning means. Specifically, the piston rod 22 is guided in a housing bore 23 and through a sealing ring, namely an O-ring 24, sealed relative to the housing 21. A scraper ring 25 on the free end face of the housing bore 23 prevents Chips or similar impurities enter the housing bore 23.

The housing bore 23 merges into a bore 26 of larger diameter. Therefore, on the rear end of the piston rod 22, a piston ring 27 with Screwed to the bore 26 corresponding diameter. Of the Piston ring 27 is opposite in a conventional manner by O-rings 28 and 29 the housing 21 and the piston rod 22 sealed. Finally, in the Bore 26, a lid 30 screwed to close the same and also sealed by an O-ring 31 opposite the housing 21.

The piston rod 22 carries at its free, protruding from the housing 21 End a hammer head 32 in which a transverse piston 33 is guided as a clamping piece. The transverse piston 33 is in turn by an O-ring 34 opposite to the Hammer head 32 sealed. Thus, in the illustration of FIG. 1 above of the transverse piston 33, a pressure chamber 35, which via an angular bore 36 with a Pressure chamber between the piston rod 22 and the piston ring 27 on the one hand and the lid 30 communicates. The angular bore 36 is at its other, the Hammerhead 32 associated end closed by a plug 38.

In the piston rod 22, a return pin 40 is guided in a bore 39 and secured against the bore 39. The return bolt 40 is supported by a Compression spring 41 facing against a screw plug 42 on the lid 30 End of the bore 39 from. The closure screw 42 is opposite the bore 39th also sealed, so that the space between the screw plug 42 and the Return bolt 40 forms a pressure chamber 43. The return bolt 40 engages its tip 44 in a recess 45 laterally on the transverse piston 33 a.

The clamping element 20 described so far operates as follows: For clamping a Workpiece 46 on a machine table 47 or the like is first of Pressure chamber 37 between the lid 30 on the one hand and the piston ring 27 and the Piston rod 22 on the other hand acted upon by pressure medium (Connection holes 48). The piston rod 22 now moves in the dash-dotted lines shown end position. Since the pressure in the pressure chamber 37 over the Angle bore 36 also propagates into the pressure chamber 35 in the hammer head 32 must be prevented that the transverse piston 33 is already extended. This prevents the prestressed by the compression spring 41 return bolt 40. Only when the piston rod 22 has taken its end position shown in phantom, the pressure in the pressure chamber 35 increases so much that over a bevel 49 so much Longitudinal pressure is exerted on the return bolt 40, that the Biasing force of the compression spring 41 is overcome. The transverse piston 33 is now in extended the clamping position and clamps the workpiece 46th

To relax the pressure from the pressure chamber 37 and discharged accordingly from the pressure chamber 35. Then, or almost At the same time, a pressure chamber 50 in front of the piston ring 27 via a Connecting bore 51 acted upon by pressure medium. Over a Connecting bore 52 in the piston rod 22, the pressure in the Propagate pressure chamber 43. As a result, the return bolt 40 is forward against pressed the transverse piston 33 and thereby on the slope 49 of the transverse piston 33 in pulled the hammer head 32. As soon as the return bolt 40 and accordingly the transverse piston 33 have reached the extended end position, the pressure rises in the Pressure chamber 50 so far that now the piston rod 22 is retracted. The Clamping element is now in the retracted position shown.

In order to control the end position of the piston rod 22, in the housing suitable sensors, for example inductive or capacitive pickups 53 and 54 be arranged. With the help of a recessed in the piston rod 22 Magnets 55 or holes, the rear transducer 54 reports the retracted position and the hammerhead-side pickup 53 the extended Position of the piston rod 22.

The piston rod 22 and corresponding to the piston ring 27 have a round Cross-section on. Accordingly, the holes 23 and 26 with round Cross section formed. It is thus possible, the piston rod 22 to their To twist longitudinal axis and oblique clamping positions, for example, as in Fig. 3, to enable. Optionally, suitable means may be provided be to lock the piston rod 22 in their respective angular position. This happens in the specific case via a positioning pin 119, which in a Expansion 120 of the angular bore 36 engages. The positioning pin 119 is at its Flattened top, so that a channel 121 is formed for the pressure medium. Of the Positioning pin 119 continues to engage in a blind bore 122 in the lid 30 and positioned so the piston rod 22 against the lid 30. Hereby is about the lid 30 also determines the angular position of the piston rod 22, wherein the Cover 30 optionally on tuning discs in this angular position when Screwed into the housing 21 countered, or by clamping screws in his Situation is recorded.

In Figs. 1 to 3, a variant of this clamping element is shown, in which the Clamping element 20 on the machine table 47 by means of fastening screws 56th is screwed on. In the variant according to FIG. 4, the housing 21 is provided with a Flange 57 provided so that the clamping element 20 with its hammer head 32nd protrude through a plate bore or through the bore of a stand 58 and with can be screwed (fixing screws 59).

The tensioning element shown in FIGS. 5 to 8, namely linear tensioner 60, Corresponds essentially to the linear tensioner 20 shown in FIGS. 1 to 4. The same components are therefore designated by the same reference numerals. The main difference is that no separately screwed on piston ring is provided. Rather, the piston rod 61 is integrally formed with a Thickening 62 in the rear, the lid 30 facing area. Because the Piston rod 61 now from behind with unscrewed cover 30 in the housing 21st must be used, it also has no pronounced hammer head. Rather, in the bore for the transverse piston 33 only from below one Socket 63 is used, which also has a scraper ring 64, the penetration of Prevents soiling, carries.

In Fig. 5, the maximum extension stroke H ^{1 of} the piston rod 61 is additionally located. It is easy to see that this maximum stroke H ¹ corresponds to the length of the pressure chamber 50 for the retraction movement of the piston rod 61 in the retracted state of the piston rod 61. Furthermore, the stroke H ^{2 of} the transverse piston 33 is indicated.

Another difference of the linear tensioner 60 to the linear tensioner 20 is in that the recess 45 in the lower region with a bulge 65th is provided. As a result, the transverse piston 33 is even safer in the retracted Position held. It must be built up an even greater pressure in the pressure chamber 35 to tension the workpiece 46, as in the linear tensioner 20 according to Fig. 1 to 4.

Finally, the linear tensioner 60 differs from the linear tensioner 20 nor in that the connection holes 48 and 51 with leads A and B in Machine table 47 correspond. This variant is particularly suitable when multiple linear clamp 60 with a common pressure medium supply be served simultaneously. In addition, this variant also offers when the linear tensioner 60 instead of on a machine table 47 on a Workpiece change pallet is attached. In such cases, the Pressure medium supply often also on the workpiece change pallet.

The linear tensioners 20 and 60 described so far are always advantageous can be used when workpieces 46 with a large extension stroke of Piston rod 22 and 61 to be clamped. This is, however, due spatial conditions on machine tools or the like is not always possible. In such cases, then swing clamps are used, in which a Clamp 77 pivoted about the workpiece to be clamped 46 and then by lowering the clamping iron 77, the workpiece 46 is tensioned. Also in such swing vices, the invention can be advantageously integrated, such as will be explained below in the variants shown in FIGS. 9 to 15.

The swing clamp 66 shown in FIG. 9 has a pivot housing 67, in FIG which a pivot piston 68 is guided. Specifically, the swing piston 68 on the one hand in a cylinder bore 69 and on the other hand in a Cylinder bore 69 occlusive guide bushing 70 out and in itself sealed in a known manner. The pivoting piston 68 has a plate-like Thickening 71 on which the cylinder bore 69 in two pressure chambers 72 and 73 divided. In this case, the pressure chamber 72 via the connection bore A with pressurized oil for clamping in the manner to be described in more detail below, while the pressure chamber 73 via the connection bore B to relax with Pressure medium is supplied.

The pivoting piston 68 continues downward in a narrower pin 74, Which in this case a smaller diameter than that Swivel piston 68 has. The pin 74 bears one of swing clamps known spiral groove 75, which also in a conventional manner with a fixed, pressure spring loaded ball 76 cooperates and by the stroke of Swivel piston 68 provides for a pivoting movement thereof. Of the Angular region over which the spiral groove 75 extends, determines the Swivel angle of the swivel piston 68. At the free end of the Swivel piston 68 is a clamping iron 77 non-rotatable with the Swivel piston 68 attached. This clamp iron 77 carries the analogous Piston rod 22 of the linear tensioner 20 and the piston rod 61 of the Linearspanners 60 the transverse piston 33, so that here the same parts with the same Reference numerals are designated.

The pressure chamber 35 for the extension movement of the transverse piston 33 corresponds via the angular bore 36 with a transverse bore 78 in the rotary piston 68, which again via a riser 79 with the pressure chamber 72 for the Clamping movement of the swing clamp 66 corresponds. The pressure chamber 43 corresponds via a riser 80 and a transverse bore 81 with the Pressure chamber 73 for relaxing the swing clamp 66. The pressure chamber 43 goes in the present case transversely through the pivot piston 68 therethrough. He will on the one hand, as already described above with reference to the linear tensioners 20 and 60, through the locking screw 42 and on the other hand by the return bolt 40th limited and takes on the compression spring 41. Locking screw 42 and Return bolts 40 are arranged in clamping iron 77.

The operation of the swing clamp 66 is analogous to the operation of the Linear tensioner 20 or 60. To tighten the swing clamp 66 is on the Connecting bore A of the pressure chamber 72 applied with pressure medium. This will the pivot piston 68 in the illustration of FIG. 1 pressed down, whereby he due to the spiral groove 75 to the corresponding, preselected Angle amount pivoted. Once the pivot piston 68 is fully pivoted is, and axially free from plan and movement in the pivot housing 67, the rises Pressure, which extends through the holes 79, 78 and 36 in the pressure chamber 35th propagates so far that the biasing force of the spring 41 overcome and the Return bolt 40 to the rear on the pivoting piston 68 to due to Bevel 49 is pressed. The transverse piston 33 is lowered onto the workpiece and tense this.

To release the pressure from the pressure chambers 35 and 72 is drained. At the same time or slightly offset in time, the pressure chamber 73 via the Connection hole B supplied with pressure medium. The in the pressure chamber 73rd Anabolic pressure builds up via the bores 80 and 81 into the pressure chamber 43 continued. As a result, first the return bolt 40 forward on the Cross piston 33 to pressed and thereby on the slope 49 of the transverse piston 33rd recovered. Then is due to a further increase in the Hydraulic pressure of the pivot piston 68 is pushed upwards and thereby due to Spiral groove 75 swung back.

In the swing clamp of FIG. 9, the clamp iron 77 only during the Pivoting movement still a the stroke of the rotary piston 68 corresponding Hub off. This is not always desired and shown in Figs. 10 to 15 Swing clamps 82 and 108 avoided: Here the clamp iron 77 executes only one pure pivoting movement without axial stroke. The advantage: Build the swing clamps lower and the swivel mast 85 is better protected against contamination.

The swing clamp 82 has a pivot base 83, on the means of a Socket 84 a pivoting mast 85 is mounted. The mast 85 is here relative to the pivot base 83 rotatable about its longitudinal axis. By doing Swivel base 83 and the pivot mast 85, a displacement 86 is formed, which is about half of its length respectively in the swivel mast 85 and swivel base 83rd located. In this displacement 86, a pivot piston 87 is guided. This instructs its outer periphery a spiral groove 88, which with a spring-loaded Ball 125 cooperates, which in obstruction of the pivoting movement of Clamping iron 77 as overload fuse from the spiral groove 88 disengages. To the Clamping the swing clamp is on the pressure medium connection A. Pressure chamber 89 below the pivot piston 87 acted upon by pressure medium. Of the Rotating piston 87 is thereby raised in the illustration of FIG. 10 and pivoted as a result of the spiral groove 88 of the rotary piston 87, in turn, the Angular range of the spiral groove 88 and the pivot angle determined. About one in a groove 90 guided on the rotary piston 87 ball 91 is this Transfer pivoting movement on the swivel mast 85. To the free end of the Schwenkmastes 85 is again a clamping iron 77 mounted non-rotatably. When Anti-rotation serves in the present case, another ball 92. After the Swivel piston 87 is completely raised, so the swivel mast 85 and thus the clamping iron 77 is completely pivoted, the pressure in the pressure chamber 89 increases continue on. This pressure is planted on a riser 93, a in the Rotating piston 87 on the one hand and the pivot mast 85 on the other sealing guided connecting pipe 94, a further riser 95 in the pivot mast 85th and a transverse bore 96 and the angular bore 36 in the pressure chamber 35 for the Extending movement of the transverse piston 33 continues. The pressure in the pressure chamber 35 increases So far, that the biasing force of the compression spring 41 overcome and the Return bolt 40 out of the bulge 65 out and on the swivel mast 85 too is pressed. In this case, the transverse piston 33 is lowered onto the workpiece 46 and tense this.

To relax, in turn, via the pressure medium connection A, the pressure from the Pressure chambers 35 and 89 drained. At the same time or slightly delayed via the connection bore B via a channel 97 a in Fig. 10 not recognizable Pressure chamber 124 above the pivot piston 87 acted upon by pressure medium. This pressure chamber corresponds via an angular bore 98 with the Pressure chamber 43 for the return bolt 40. The return bolt 40 is characterized again pressed to the cross piston 33 and thereby pushes the cross piston 33rd on the slope 49 upwards, so that the transverse piston 33 in the clamping iron 77th is withdrawn. A spring-loaded ball 99 prevents in this position that already now the pivot piston 87 is pressed down. Only through further Increase of the hydraulic pressure after the cross-piston 33 is retracted is overcome the force of the ball 99 and pushed the pivot piston down. As a result, then the pivoting piston 87 itself and with it the pivoting mast 85 and the clamping arm 77 swung back.

Fig. 11 shows a possible combination of valves, which ensures that the pressure chamber 35 is supplied with pressure medium only when the Swivel piston 87 has reached its upper end position. Such In particular, valve combination is always advantageous when lifting the pivoting piston in the pressure chamber 89 required pressure in about the Extending the transverse piston 33 required pressure in the pressure chamber 35 corresponds, or the spring pressure on the return bolt 40 is insufficient.

In Fig. 11 is centrally in the pivot mast 85 below a spring 100 the Riser hole 95 recognizable. The spring 100 presses a valve ball 101 into its seat, so that a bore 102 is closed. Will now through the riser 95th Added pressure medium, presses the resulting pressure continues on the Ball 101 and closes the valve. The pressure medium passes through a Abzweigbohrung 103 against another spring-loaded valve ball 104 and presses this back against the force of the spring 105, so that a channel is released. The Pressure fluid now enters a transverse bore 106 and from there via a Ring groove 107 in the angular bore 36. The pressure chamber 35 above the Querkolbens 33 is acted upon by pressure medium. When relaxing in the as described above, pressure is applied to the return bolt 40 which attempts to to draw in the transverse piston 33. This also increases the pressure in the Pressure chamber 35, which is back via the angular bore 36 and the annular groove 107 in the transverse bore 106 propagates. The valve ball 104 is supported by the Compression spring 105, closed. At the same time, the pressure on the valve ball 101 increases so strong that it is pushed out of its seat and a channel is released. The Pressure fluid can now drain through the riser 95.

In the particularly low swing clamps 108 shown in FIGS. 13 to 15 the swivel mast 85 is not operated via a swivel piston with spiral groove. Rather, the pivoting piston 109 is here in the pivot base 83 below the Swivel mast 85 arranged. He has at its top a transverse Groove 110 into which a pin 111 engages. The pin 111 is connected by a compression spring 112 biased against the pivot piston 109 and can by the trapezoidal Embodiment of the groove 110 in a disability of Disengage clamping swivel movement.

If now a pressure chamber 113 is pressurized via the connection bore A, is the pivot piston 109 in the illustration of FIG. 14 and 15 upwards pressed. He takes the pin 111 with it and thereby turns the Slewing mast 85. Except in the pressure chamber 113, the pressure medium passes through a Ring groove 114 in a channel 115 and from there via a further annular groove 116 in the Angular bore 36. As a result, the pressure chamber 35, as already several times described, supplied for the transverse piston 33 with pressure medium.

To relax again pressure medium via the pressure medium connection B. fed, which via a channel 117 in the pivot base 83 and a Rising bore 118 passes into the pressure chamber 43 for the return bolt 40. Of the Cross piston 33 is thereby in the manner already described several times above moved in. Then, the pressure rises so far that the pivoting piston 109th pressed back again and thus the clamping arm 77 on the swivel mast 85th is swung back again.

LIST OF REFERENCE NUMBERS

20

linear tensioner

21

casing

22

piston rod

23

housing bore

24

O-ring

25

scraper

26

drilling

27

piston ring

28

O-ring

29

O-ring

30

cover

31

O-ring

32

hammerhead

33

cross pistons

34

O-ring

35

pressure chamber

36

angle hole

37

pressure chamber

38

Plug

39

drilling

40

restoring bolts

41

compression spring

42

Screw

43

pressure chamber

44

top

45

recess

46

workpiece

47

machine table

48

connecting bore

49

slope

50

pressure chamber

51

connecting bore

52

connecting bore

53

pickup

54

pickup

55

magnet

56

mounting screws

57

flange

58

stand

59

screw

60

linear tensioner

61

piston rod

62

thickening

63

Rifle

64

scraper

65

bulge

66

swing clamps

67

swivel case

68

Rocking piston

69

bore

70

guide bush

71

thickening

72

pressure chamber

73

pressure chamber

74

spigot

75

spiral

76

Bullet

77

clamps

78

cross hole

79

rising bore

80

rising bore

81

cross hole

82

swing clamps

83

swivel base

84

Rifle

85

swivel mast

86

capacity

87

Rocking piston

88

spiral

89

pressure chamber

90

groove

91

Bullet

92

Bullet

93

rising bore

94

connecting pipe

95

rising bore

96

cross hole

97

channel

98

angle hole

99

Bullet

100

feather

101

valve ball

102

drilling

103

branch bore

104

valve ball

105

feather

106

cross hole

107

ring groove

108

swing clamps

109

Rocking piston

110

groove

111

pen

112

compression spring

113

pressure chamber

114

ring groove

115

channel

116

ring groove

117

channel

118

rising bore

119

positioning

120

widening

121

channel

122

blind hole

123

pressure chamber

124

pressure chamber

125

Bullet

Claims (15)

Clamping element for clamping workpieces (46), tools, molds or devices on machine tables (47) or pallets, with a movable positioning means (22, 61, 77) and a clamping piece (33) guided on the positioning means (22, 61, 77) , characterized in that the clamping piece (33) during the movement of the positioning means (22, 61, 77) is locked, such that it is operable only at the end of the movement of the positioning means (22, 61, 77). Clamping element according to claim 1, characterized in that the clamping piece (33) is secured in the retracted position by means of a, in particular in its locking position by a compression spring (41) biased and / or fluid-actuated, return bolt (40). Clamping element according to claim 2, characterized in that the return bolt (40) engages in a recess (45), in particular with a bulge (65) in the clamping piece (33). Clamping element according to claim 3, characterized in that the recess (45) is provided with a bevel (49), such that the clamping piece (33) is retracted by actuating the return bolt (40) in the direction of the clamping piece (33). Clamping element according to one of claims 1 to 4, characterized in that a pressure chamber (35) for the clamping piece (33) with a pressure chamber (37, 72, 89, 113) corresponds. Clamping element according to claim 4 or 5, characterized in that a pressure chamber (41) for the return bolt (40) with a pressure chamber (50, 73, 123, 124) corresponds. Clamping element according to one of claims 1 to 6, characterized in that the positioning means (22, 61) has two bores (39, 36) extending in the longitudinal direction of the positioning means (22, 61), of which the one bore (39). the return pin (40) and the other bore (36) in a widening (120) thereof receives a positioning pin (119) for fixing an angular position of the positioning means (22, 61) about its longitudinal axis. Clamping element according to claim 7, characterized in that the other bore (36) at the same time a pressure medium channel for connecting the pressure chamber (35) for the clamping piece (33) with the pressure chamber (37) for the positioning means, in particular wherein the positioning pin (119) for Release of the pressure medium channel is flattened (channel 121). Clamping element according to one of claims 1 to 8, characterized in that the positioning means (22) with a screwed-on piston ring (27), wherein at its free end a hammer head (32) for receiving the clamping piece (33) is mounted. Clamping element according to one of claims 1 to 8, characterized in that the positioning means (61) is integrally formed, and in particular with a screwed into the free end of the positioning means (61) bushing (63) is provided. Clamping element according to one of claims 1 to 6, characterized in that the positioning means as clamping iron (77) of a pivoting clamp (66, 82, 108) is formed and has two mutually parallel bores, one of which bore a pivot piston (68) and a pivot mast (85) receives, while the other bore receives the clamping piece (33), in particular wherein the pivoting mast (85) has a collar, by means of which the pivoting mast (85) between a pivot base (82) and a pivot bushing (84) is held , Clamping element according to claim 11, characterized in that the pivoting mast (85) has a bore centrally for receiving a pivoting piston (87) arranged displaceably therein, wherein a pressure medium bore (95) adjoins the bore, which via a connecting tube (92) with a pressure medium bore (93) in the rotary piston (87), in particular wherein the sealed length of the connecting tube (92) is more than twice as long as the stroke of the rotary piston (87), wherein the connecting tube (92) in each case further into the pivoting mast (85) and the pivotal piston (87) engages as it corresponds to the stroke of the pivoting piston (87). Clamping element according to Claim 12, characterized in that the swivel piston (87) has a spiral groove (88) for converting the piston stroke into a rotary movement and, on the other hand, a longitudinal groove (90) for transmitting the rotational movement from the swivel piston (87) to the swivel mast (85). Clamping element according to claim 11, characterized in that a pivoting piston (109) displaceable transversely to the longitudinal axis of the pivoting mast (85) is arranged in the pivoting base (83), which has a coupling element (groove 110) which in turn is eccentrically mounted on the pivoting mast (85). arranged coupling element (pin 111) corresponds, such that by the stroke of the pivoting piston (109) of the pivoting mast (85) is rotated about its longitudinal axis. Method for clamping workpieces (46), tools, molds or devices on machine tables (47) or pallets with a tensioning element (20, 60, 66, 82, 108), comprising a movable positioning means (22, 77) and a positioning means (22, 77) movably guided clamping piece (33), characterized in that the clamping piece (33) is actuated only at the end of the movement of the positioning means (22, 77).

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