Patent Application
20120227355
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.
The disclosure relates to a closing tool of the type used in beverage bottling operations.
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.
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.
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.
Preferably, the gripping device according to the disclosure is provided with gripping members which a movable towards each other.
The gripping members may be pivotable about an axis so as to carry out gripping movements and releasing movements, whereby the gripper'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.
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.
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.
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.
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.
Preferably there are possibilities that allow the adjustment of the magnetic force so as to account for different mechanical strengths of the closures.
Embodiments of the disclosure are explained in more detail below by means of the drawings. In the drawings:
As can also be seen in conjunction with
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.
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 8a, 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 8b 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 8b 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
This kind of magnetic actuator 11 is suited particularly for the clean room embodiment or aseptic embodiment according to
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.
The drive movements may also be generated by other means, however, e.g. pneumatically, electrically or electromagnetically.
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.
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.
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
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.
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.
The closing tool 205 further comprises on its holder 206 a driving gear tooth system 219 for producing the screwing movement.
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.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102011005306.9 | Mar 2011 | DE | national |
