Clamping device

The present invention relates to a tensioning device for fixing an insertion bolt on a machine table, a clamping plate or the like having a Receptacle into which the draw-in bolt can be inserted, and a tensioning mechanism for the draw-in bolt in the receptacle fix, wherein the clamping mechanism comprises a Collet with several clamping tongues which at arranged at one end to one in the receptacle are fixed retaining element and at its free end between a radially inner clamping position and a outer release position and by a piston are locked in the clamping position.

Tensioning devices of this type are known from DE 200 03 729 U1. These clamping devices occurs here the fixing of a draw-in bolt in the receptacle of the Clamping device by a collet, the more resilient having clamping tongues, which at their one end region fixed to one held in the receiving ring member and in the region of their free ends, with elastic Deformation between a radially inner clamping position are and a radially outer release position. For actuation of the clamping mechanism a piston is provided, by a spring assembly in a lower closed position is pressed, in which the clamping tongues radially are pressed inward in its clamping position, and the hydraulically into an upper release position, in which it releases the clamping tongues, so that these radial can avoid outward. Furthermore, has the actuated clamping mechanism comprises a hydraulic or pneumatic Opening flask inside with the clamping tongues is so engaged that the free ends of the Clamping tongues by an axial movement of the piston opening can be spread into the release position and thus the holding bolt from the recording taken or can be inserted into these.

The known clamping mechanism has in practice although operated well. However, it is considered to be disadvantageous, that it has a relatively complicated construction. Furthermore it is criticized in part, that the clamping device is difficult to handle because of the insertion bolt must exactly be positioned in the clamping device, so that the clamping mechanism operates reliably.

Object of the present invention is therefore, a indicate clamping device of the type mentioned, which has a simple structure, reliable working and is easy to handle.

This object is inventively achieved in that the Holding member with the clamping tongues axially displaced and is arranged with radial play in the receptacle. By this radially floating and axially shiftable arrangement the collet can not only holding forces, but large drawing forces are transmitted. In addition, Manufacturing errors are compensated, so that a reliable Function is guaranteed.

In an embodiment of the invention provides that the Clamping tongues in their initial position, the clamping position taking, in which it is in contact with a contact surface a holding bolt inserted into the clamping device are provided, wherein the contact surface in the transition region to a thickened bolt head is provided. Through this Embodiment it is achieved that the tensioning device no separate opening mechanism is required because the with a corresponding contour provided the holding bolt Clamping tongues radially pressed outwardly when the holding bolt pulled out of the receptacle or used in this becomes.

Finally, in a conventional manner is provided, that the clamping tongues on the outside in the region of their free ends conically diverge, while at their form outer sides sloping surfaces that with the piston cooperate attached and cone surface to the clamping tongues employed radially inwardly against one into the receptacle press insertion bolt, as the piston is in its clamping position. This is achieved that during the clamping operation, the incorporated into the flask Taper contour axial movement of the piston in reacting an axial and radial clamping movement of the clamping tongues. The clamping bolt is during retraction by the bias the clamping tongues easily held and thereafter at Tensioning process drawn into the cylinder.

Regarding further advantageous embodiments of the Invention to the dependent claims and the subsequent Explanation of embodiments with reference reference is made to the accompanying drawings. In the Drawing shows:<dl tsize="6"><dt>Fig. 1</dt><dd>designed as a construction cylinder clamping device according to the present invention in perspective view,</dd><dt>FIG. 2</dt><dd>the tensioning device of FIG. 1 taken along the line II-II with actuated clamping mechanism and</dd><dt>Fig. 3</dt><dd>designed as a mounting cylinder clamping device according to the present invention in corresponding to one of Fig. 2 a longitudinal section with dissolved clamping mechanism.</dd></dl>

In the figures, two variants of a mechanical / hydraulic Clamping device 1 according to the present Invention shown, for example, to is a support pallet with an attached Workpiece and mind back a respective pull stud on a machine table, a base plate or the like to be tightened. The two shown clamping devices 1 have substantially the same basic structure and the same operation as described below are:

The clamping devices 1 each comprise a base body 2, which forms a cylinder bore 3, in the under Forming a pressure chamber 4, a piston 5 axially movable is used. In the pressure chamber 4 opens a bottom side in the main body 2 formed channel 2b, through which the pressure chamber 4, a hydraulic fluid to be fed can.

The open top of the body 2 is defined by a Cover 6 is closed, the the on a flange 2a Basic body 2 rests and on the main body 2 six bolts is fixed 7th On the underside of the cover is a centering shoulder 8 formed which is communicated accurately to Diameter of the cylinder bore 3 is dimensioned so that the cover 6 is positioned precisely positioned on the base body 2 can be. Between the cover 6 and the piston 5 is a disk spring assembly arranged 9, the piston 5 towards the bottom of the cylinder bore 3 down applied.

In the pressure chamber 4 opposite top side of the Piston 5 is a blind hole provided, recording a 10 forms a holding bolt 11, which in the Recording 10 through an opening provided in the cover 6 through hole 12 may be used.

To fix the holding bolt 11 in the receptacle 10 a clamping mechanism is provided by the axial movement the piston 5 is actuated and a collet having. This collet possesses several along the Scope of the holder 10 and arranged tongue-like design Clamping elements 13, which at its upper end to a retaining ring 14 are held, wherein the clamping tongues 13 spread open elastically at their free ends or together can be pressed. The retaining ring 14 is inserted into the through hole 12 of the cover 6 and there displaced axially and with radial play (Floating) held, the axial path towards upwards limited by a fixed to the lid 6 snap ring 15 is.

In the area of ​​its free, lower ends, the clamping tongues 13 engaging lugs 16 which in its in Figure 1 Initial position in contact with a in the illustrated Tensioning device 1 used Holding bolt 11 are, to submit to lock in the recording 10th At the draw-in bolt 11 is a corresponding contact surface 17 in Transition area provided for thickened bolt head 11a, via which the axial fixation is done.

As can be clearly seen in the drawing, through the clamping tongues 13 outside the cone-like in the area of ​​their free ends apart, while on their outsides form bevels 18th These oblique surfaces act 18 with an attached and the flask 5 conical surface 19 together, the clamping tongues 13 in its initial position radially inwards against an inserted into the receptacle 10 Holding bolt to press 11 when the piston 5 from its upper release position shown in Figure 3 downward into the position shown in Figure 2 lower Clamping position is moved.

Specifically, the figure shows 3 the clamping device 1 in its Release position, in which the piston 5 by applying the pressure chamber 4 with a counter pressure medium the restoring force of the cup spring package is lifted 9, so that the retaining ring 14 between the snap ring 15 and the piston 5 is axially fixed. In this release position are the conical surface 19 of the piston 5 and the Inclined surfaces 18 of the clamping tongues 13 are not in engagement with each other, so that the clamping tongues 13 at the onset of Holding bolt 11 into the receptacle 10 or during withdrawal a holding bolt 11 from the receptacle 10 elastic can avoid outward when the thickened performed bolt head 11a between the clamping tongues 13 becomes. During insertion avoid the long guide collar 11b of the holding bolt 11 and the corresponding long through hole formed 12 of the lid 6 a Tilting or slipping of the holding bolt 11 from the Management, which is particularly important in automated manufacturing is. If now the pressure chamber 4 relieves, pushes the disk spring assembly 9 the piston 5 downward. In this case, its taper surface 19 comes into contact with the Inclined surfaces 18 of the clamping tongues 13, so that this by the piston 5 is prevented from deflecting outwardly be and thus the holding bolt 11 securely fixed becomes. Upon further movement down the entire Collet with the draw-in bolt 11 in the tensioning device 1 drawn.

If the pressure chamber 4 again acted upon by a hydraulic medium is, the piston is first 5 alone axially moves upward, so that the cone surface 19 and the Inclined surfaces 18 disengage from each other. After a certain distance then comes the piston 5 in the bottom area recording 10 into contact with the bolt head 11a, so that the latter is also raised. In that in 3 release position shown can be the insertion bolt 11 be removed from the receptacle 10, wherein the clamping tongues 13 are elastically easily spread, to free the way for the thicker bolt head 11a.

In the embodiment illustrated in Figure 3 is the Tensioning device 1 configured as a so-called installation bay in a recess of a machine table or the like can be used. In this embodiment, is an intermediate ring 20 to the base body 2 of the flange 2a opposite side pushed, the outer diameter is about the outer diameter the Grundkörperflansches 2a corresponds so that the clamping device 1 is replaced by a compact cylindrical shape. In addition, the outer edge of the lid 6 as a centering surface formed, via which the clamping device 1 can be centered in the Maschinentischausnehmung. The fixing of the clamping device 1 on the machine table takes place in this embodiment by means of six through-bolts, The alternates to the screws 7, with which the cover 6 is fixed on the base body 2, provided are, the lid 6, the base body 2 and the intermediate ring 20 extend through axially what Druchgangsbohrungen 24a, 24b, 24c are provided in the components, and in the machine table are screwed.

The clamping device shown in Figures 1 and 2 other hand, is designed as a so-called build-cylinder, the install on a machine table or the like is. For this purpose, the clamping device 1 instead of a The intermediate ring 20 has a mounting flange 21 which, is clearly visible in particular in Figure 1, four in Circumferentially extending slots 22, via which tightened the clamping device 1 on the machine table can be. In this embodiment, in the mounting flange 21 and a fluid channel 23 is formed, via which the pressure chamber supplied 4 hydraulic fluid can be.

The fixing of the mounting flange 21 on the base body 2 is similar to the installation bay by six through bolts, The alternates to the screws 7, with which the cover 6 is fixed on the base body 2, provided and which in the through-bores 24a, 24b Cover 6 and the base 2 pass through and into the mounting flange 21 are screwed. The order is made such that the mounting flange 21 the construction of the cylinder readily against the intermediate ring 20 the installation cassette can be exchanged and thus the clamping device according to the invention either as installation cassette be used as a building or cylinder can.