Abstract:
A closing tool for a closing machine for placing a closure on a container, where a holding force is applied to the closure by means of a gripping device. In order to obtain a universal embodiment for the closing tool the gripping device is provided with a magnetic actuator, such as with permanent magnets, for applying the holding force.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims the benefit of priority of German Application No. 102011005306.9, filed Mar. 9, 2011. The entire text of the priority application is incorporated herein by reference in its entirety. 
       FIELD OF THE DISCLOSURE 
       [0002]    The disclosure relates to a closing tool of the type used in beverage bottling operations. 
       BACKGROUND 
       [0003]    A closing tool of this type is known from WO 2004/009484. The known closing tool comprises a gripping device formed of a plurality of gripping segments which are grouped around a center line in a circular fashion. In use, the center line coincides with the center line of the container. The gripping segments are capable of approaching and moving away from the center line to a limited extent. This embodiment is to compensate for small tolerances which may appear on a regular basis, even if the production of the closures is carried out with utmost care, so as to reduce the error rate of closures that cannot be screwed on. To this end, the gripping segments are received in a holder in a manner radially displaceable towards the center line, and are loaded by springs in the direction of their closing position. One of the springs is placed around the outer circumference of the gripping segments in the form of an O-ring and presses the gripping segments towards the center line. Another spring acts axially towards the center line and presses the gripping segments against a holding plate provided on the lower side of the closing tool so as to produce an increased friction. However, the opening force of the gripping segments to pick up the closure has to be applied as the closing tool is pressed onto the closure in order to pick it up. The closing tool is pressed onto the closure from above. At the same time, a beveled intake on the gripping segments ensures that the closure can force the gripping segments apart in the radial direction, both against the force of the annular spring and the frictional force on the support plate, until the closure abuts against a stop inside the tool. Both the O-ring spring and the friction on the support plate then ensure that the gripping segments do not drift apart more, allowing the closure to be retained. The load margin of an O-ring is limited, however, so that only small differences in the closure sizes can be covered. 
       SUMMARY OF THE DISCLOSURE 
       [0004]    Thus, the disclosure has as one aspect to render a closing tool for a closing machine for placing a closure on a container universally usable. 
         [0005]    The magnetic actuator employed in accordance with the disclosure strongly increases the tolerance range to be coped with by the gripping device, namely in view of dimensions/tolerances and in view of contour or in view of mechanical strength. 
         [0006]    Preferably, the gripping device according to the disclosure is provided with gripping members which a movable towards each other. 
         [0007]    The gripping members may be pivotable about an axis so as to carry out gripping movements and releasing movements, whereby the gripper&#39;s travel for correctly gripping the closure is not limited to the actual dimensions of the closure because the closure need not open the gripper. Furthermore, the operation of the closing tool according to the disclosure is more gentle because the gripping (picking) takes place without friction between the closure and the gripping device, and the opening force of the gripping device need not be applied by the closure. 
         [0008]    Within the framework of the physical principles (unlike poles attract each other, like poles repel each other) there exist the most different technical solutions for the magnetic actuator. For example, the magnets of the magnetic actuator may be changed from a position with like poles opposing each other into a position with unlike poles opposing each other by means of a relative displacement or rotational movements. 
         [0009]    In one embodiment the gripping members are arranged circularly about a center line and are mounted pivotably about a pivot axis, and one magnet of the magnetic actuator is disposed on the gripping member, while the second magnet of the gripping device is fixed to a holder which is movable along the center line in such a way that the gripping device is opened or closed by magnetic attraction and magnetic repulsion. This embodiment has the additional advantage that the closing tool can thus be easily equipped for an aseptic operation, wherein merely the holder is received in a sealed sleeve (pervious to the magnetic field) so that a contamination of the aseptically held closing tool from the drive side (screwing and stroke movements) is prevented. 
         [0010]    A particularly simple construction is obtained if the gripping members are arranged in a holder to be radially displaceable and the magnets of the magnetic actuator are arranged around the gripping segments distributed to two concentric circles. 
         [0011]    In addition to the magnetic actuation of the gripping device, also other necessary movements of the closing tool can, at least partially, be generated by magnetic force, e.g. a stroke movement towards and away from the container, but also a screwing movement. 
         [0012]    Preferably there are possibilities that allow the adjustment of the magnetic force so as to account for different mechanical strengths of the closures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    Embodiments of the disclosure are explained in more detail below by means of the drawings. In the drawings: 
           [0014]      FIG. 1  shows a longitudinal section through a closing element of a closing device comprising a closing tool according to the disclosure, 
           [0015]      FIG. 2  shows an enlarged view of the closing tool of  FIG. 1 , 
           [0016]      FIG. 3  shows a modified embodiment of the closing tool of  FIG. 2 , 
           [0017]      FIG. 4  shows the magnetic actuator of the closing tool of  FIG. 3 , 
           [0018]      FIG. 5  shows a longitudinal section through another embodiment of a closing tool according to the disclosure, 
           [0019]      FIG. 6  shows a perspective view of another embodiment of a closing tool according to the disclosure, and 
           [0020]      FIG. 7  shows a longitudinal section through the embodiment of  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0021]      FIG. 1  shows in a schematic view and in a longitudinal section a closing unit  1  of a closing machine for closing non-illustrated containers with a closure  2 . The closing unit  1  according to the illustrated embodiment is designed for aseptic operation, and comprises a partition wall  3  of the closing machine which separates a clean room area RR from a gray room GR. The partition wall  3  divides the closing unit  1  into a drive part  4  and a closing tool  5 . 
         [0022]    As can also be seen in conjunction with  FIG. 2 , the tool  5  comprises a case  6  in which a gripping device  7  is accommodated. Preferably, the gripping device  7  is accommodated in the case  6  to be exchangeable and can be exchanged for the purpose of handling different closures. In particular, if the design is for an aseptic operation, these components are mounted free from gaps and in a sealed manner. 
         [0023]    In the embodiment as illustrated, the gripping device  7  comprises a plurality of gripping members  8  in the form of gripping segments, which are grouped around the center line  7 ′ of the gripping device  7 . The term “gripping member” covers any structure capable of gripping and retaining the closure  2 . 
         [0024]    Each gripping member  8  is pivotable about a substantially horizontal rotation axis  9  in the form of a bolt or something of that kind into a gripping position so as to hold the closure, and a releasing position so as to release the closure. The rotation axis  9  subdivides the gripping member  8  into a lower arm  8   a,  which is provided with gripping elements  10 , such as engagement projections or corrugations or something of that kind, by means of which the closure  2  can be held securely, and an upper arm  8   b  acted on by a magnetic actuator  11  for pivoting the gripping members  8  about the rotation axis  9  and, thus, for opening and closing the gripping device  7 . The magnetic actuator  11  preferably comprises permanent magnets and is based on the known physical principles that like poles of permanent magnets repel each other and unlike poles attract each other. The magnetic actuator  11  in the illustrated embodiment is realized in a linear combination, with a first magnet  12  and a second magnet  13  being located in an axial direction side by side along the center line  7 ′ on the second arm  8   b  of the gripping member  8 . The two magnets are oriented such that they are pointing with different poles to the center line  7 ′. In the embodiment shown, the upper magnet  12  points with its north pole and the lower magnet  13  with its south pole to the center line  7 ′. The magnetic actuator  11  further comprises a third magnet  14 , which is responsible for all gripping members  8 , however. The third magnet  14  is preferably an annular magnet, whose outer circumference includes the north pole. The third magnet  14  is fixed to a holder  15  in the form of a holding rod, which runs coaxially with respect to the center line  7 ′, and is movable in the direction of actuation B from its position opposite the first magnet  12 , as shown in  FIG. 2 , to a position opposite the second magnet  13 , and back. If the third magnet  14  is positioned at the level of the first magnets  12  of all gripping members  8 , the gripping members  8  are pivoted by repulsion into the closed position shown in  FIG. 2 , wherein the gripped closure  2  can be retained and screwed on. If this has been accomplished, the third magnet  14  moves downwards along the center line  7 ′ until it is located opposite the second magnets  13  of all gripping members  8 . Now, the attraction takes place, which pivots the gripping members  8  about the rotation axis  9  into an opened position, in which the closure  2  is released. 
         [0025]    This kind of magnetic actuator  11  is suited particularly for the clean room embodiment or aseptic embodiment according to  FIG. 1 , wherein merely the holding rod  15  with the third magnet  14  is accommodated in a closed, sleeve-like ejector rod  16  (pervious to magnetic fields). This ejector rod  16  is easy to seal by means of a sleeve  17 , which is fixed all around a through opening  18  through the partition wall  3  in a sealing manner, and on the bottom of which the ejector rod  16  is fixed, again by sealing the through opening. The driving movement with respect to the screwing rotation can be transmitted, for example by means of a gearwheel coupling  19 , to a rotating sleeve  20 . By means of a magnetic actuator in the form of a magnetic coupling  21  the rotating sleeve  20  transmits the rotation to an inner sleeve  22  on which the tool  5  is mounted (preferably releasably by a corresponding coupling  23 ). 
         [0026]    The stroke movement to the tool  5  for opening and closing the gripping members  8  is likewise accomplished by the magnetic coupling  21 , with the stroke movement only being transmitted during the screwing movement. The movement of the holding rod  15  is carried out separately from the stroke movement and independently of the drive system thereof. 
         [0027]    The drive movements may also be generated by other means, however, e.g. pneumatically, electrically or electromagnetically. 
         [0028]    On the lower side of the gripping members, which is opposite the closure  2 , stops  25  for the insertion depth of the closure  2  into the tool may be provided, preferably in an exchangeable manner. 
         [0029]      FIGS. 3 and 4  show a modified embodiment of a closing tool  105 , which differs from the embodiment of  FIGS. 1 and 2  merely by another arrangement of the magnets of the magnetic actuator  111 . In the closing tool  105 , the holding rod  115  accommodated in the ejector rod  116  comprises the magnet assembly  114  as shown in  FIG. 4 , whereof a plurality of magnets  114   a  to  114   f  are arranged circularly and with alternating polarities about the center line  7 ′, so that a south pole and a north pole, respectively, are pointing alternately to the outside, i.e. away from the center line  7 ′. 
         [0030]    The gripping members  8  in the form of gripping segments are here merely provided with the first magnets  12 , which are arranged on all three segments, pointing with the same polarities to the inside, i.e. towards the center line  7 ′. In the embodiment illustrated this is the north pole. 
         [0031]    In this embodiment the holding rod  15  is not longitudinally displaced, axially relative to the center line  7 ′, but is rotated about the center line  7 ′, as is shown by arrow D. Thus, after each ⅙ rotation, another pole is brought into a position opposite the first magnets  12  on the gripping segments, wherein, as shown in  FIG. 4 , firstly a repulsion takes place so as to close the gripping device, while an attraction takes place in the next step so as to open the gripping segments. This embodiment of the closing tool  105 , too, is clean room compatible and aseptically suitable. 
         [0032]      FIG. 5  shows another embodiment of a closing tool  305  according to the disclosure, exhibiting features of the two preceding embodiments Like or comparable components are designated with reference numbers increased by 300, and are not explained again. The closing tool  305  comprises a plurality of gripping segments  308 , which are pivotable about a pivot axis  309 . The so formed lower arm  308   a  is provided with the gripping members  10 , and the upper arm  308   b  carries a magnet  312 . The counter-magnet(s)  314  are fixed to a swivel  337  of the holder  306 , so as to achieve the interaction already described above between attraction for opening and repulsion for closing the gripping device  311 . 
         [0033]      FIGS. 6 and 7  show another embodiment of a closing tool  205  according to the disclosure, which is characterized by a simple design. The closing tool  205  comprises a gripping device  207  with a plurality of gripping members  208  in the form of gripping segments, which are circularly arranged about the center line  7 ′. The gripping members  208  are displaceable in the direction of the double arrow S towards the center line  7 ′ and away from the center line  7 ′, however, which may be obtained by suitable guides, such as the guide rod  226  shown. Tool  205 , too, comprises a magnetic actuator  211  with first magnets  212  and opposite (third) magnets  214 , which are arranged on concentric circles about the center line  7 ′. 
         [0034]    Like in the preceding embodiments, the closing tool  205  may be designed to move the gripping members  208  into a gripping position and a release position with respect to the closure  2 , this time by a displacement, which is achieved by mounting the magnets  214  in the circle about the center line  7 ′ with alternating polarities, respectively, so that by rotating the holder  206  different polarities are opposite the magnets  212 . 
         [0035]    It is preferred, however, that the magnets  214 ,  212  are stationary and mounted in such a way that like polarities are positioned opposite each other so as to generate a repulsion. Thus, the magnetic force and gap L are adjusted in such a way that the gripping members  208  surround a space about the center line  7 ′ which is at least equal to, preferably smaller than the diameter of the closure to be picked up. The gripping members  208  are, and this is of particular importance, provided with beveled intakes  37  on their lower sides, so that the closure forces the gripping members  208  apart against the repulsion force of the magnets  212 ,  214  as the tool  205  is placed down, thereby applying the holding force as the closure  2  is handled and as the closure  2  is put on. When the tool  205  is withdrawn from the closed container the gripping members  208  return into their initial position as a result of the repulsion force of the magnets  212 ,  214 . 
         [0036]    The closing tool  205  further comprises on its holder  206  a driving gear tooth system  219  for producing the screwing movement. 
         [0037]    Due to the mounting in the modified embodiment as illustrated, and also in the embodiments described, there may be a possibility to adjust the magnetic force. This may be accomplished, for example, by varying the distances between the mutually influencing magnets of the magnetic actuator. In the embodiment shown, the magnets  214  are each received in holders  236 , which are fixed to holder  206  in an individually adjustable manner, so that the gap L between the magnets  212 ,  214  along the guide rod  226  can be adjusted. 
         [0038]    In a modification of the embodiments described and illustrated the closing tools according to the disclosure may also be designed with other gripping members, e.g. gripper arms, which have a greater distance between them. Also, a special embodiment for special shapes of closures is possible. Finally, details in the figures may be interchanged. For example, the depth-control stops for the closures for the depth and/or the adjustability of the magnetic force may be provided in all embodiments.