Ellis
John
LTD.
| 1. | : A palletizing system for placing articles from a conveying means onto a pallet comprising in combination a) at least one first track, and a second track having a longitudinal axis, said first track or tracks adapted to move along said second track; b) at least one gripper means adapted to engage at least one article to be palletized, said gripper depending from a translatable carriage means on one of said first tracks; c) means for moving at least one pallet along a vertical axis; and d) control means responsive to a predetermined instruction set for controlling the movement of said first track or tracks along said second track, each of said translatable carriages, said gripper means and said means for moving, such that after one or more articles have been placed on one layer on a pallet on one of said means for moving, the means for moving moves downward to allow for articles to be placed on the next layer with minimal or no vertical movement of said gripper. |
| 2. | A palletizing system as claimed in claim 1 wherein said means for moving moves downward to a new base level after a layer of articles has been completed on said pallet. |
| 3. | A palletizing system as claimed in claim 1 or claim 2 wherein the means for moving can be rotated around a vertical axis. |
| 4. | A palletizing system as claimed in claim 1 or claim 2 wherein the gripper can be rotated around a vertical axis. |
| 5. | A palletizing system as claimed in claim 1 or claim 2 wherein a conveyor bringing articles to said palletizing system incorporates an article orientating device. |
| 6. | A palletizing system as claimed in claim 1 wherein said first track is cantilevered with respect to said second track. |
| 7. | A palletizing system as claimed in claim 1 wherein a third track parallel to said second track is utilised to support said first track. |
| 8. | A palletizing system as claimed in claim 7 wherein vertical support members are provided for said second and third tracks, and said means for moving comprises a drive mechanism disposed along the vertical support members. |
| 9. | A palletizing system as claimed in claim 1 , wherein said gripper means includes projecting tines for engaging the lower side of an article, and said conveying means includes a portion formed of rollers, such that the tines may interleave the rollers to engage an article. |
| 10. | A palletizing system according to claim 1, wherein said first track is driven relative to said second track from only one end of said first track. |
| 11. | A palletizing system for placing articles from a conveying means onto a pallet comprising in combination: (a) At least a first and second track having a longitudinal axis, said first track adapted to move along said second track; (b) At least two gripper means to engage at least one article each to be palletized, said grippers depending from a translatable carriage means on said first track; (c) Two pallet tables adapted to move along a vertical axis; (d) Control means responsive to a predetermined instruction set for controlling said first tracks movement along said second track, said translatable carriage, said gripper means and said tables, such that after one or more articles have been placed on one layer in each pallet, the respective pallet table moves downwards to allow for articles to be placed on the next layer with minimal or no vertical movement of said grippers. |
| 12. | A palletizing system as claimed in claim 11 wherein said means for moving moves downward to a new base level after a layer of articles has been completed on said pallet. |
| 13. | A palletizing system as claimed in claim 11 or 12 wherein the means for moving can be rotated around a vertical axis. |
| 14. | A palletizing system as claimed in claim 11 or 12 wherein the gripper can be rotated around a vertical axis. |
| 15. | A palletizing system as claimed in claim 11 or 12 wherein a conveyor bringing articles to said palletizing system incorporates an article orientating device. |
| 16. | A palletizing system as claimed in claim 11 wherein said first track is cantilevered with respect to said second track. |
| 17. | A palletizing system as claimed in claim 11 wherein a third track parallel to said second track is utilised to support said first track. |
| 18. | A palletizing system as claimed in claim 17 wherein vertical support members are provided for said second and third tracks, and said means for moving comprises a drive mechanism disposed along the vertical support members. |
| 19. | A palletizing system as claimed in claim 11 or 12, wherein said gripper means includes projecting tines for engaging the lower side of an article, and said conveying means includes a portion formed of rollers, such that the tines may interleave the rollers to engage an article. |
| 20. | A palletizing system according to claim 11, wherein said first track is driven relative to said second track from only one end of said first track. |
| 21. | A palletizing system for placing articles from a conveying means onto a pallet comprising in combination a) at least one first track, and a second track having a longitudinal axis, said first track or tracks being adapted to move along said second track; b) a respective gripper means adapted to engage at least one article to be palletized, said gripper means depending from a respective translatable carriage means on each of said first tracks; c) means for moving at least one pallet along a vertical axis; and d) control means responsive to a predetermined instruction set for controlling the movement of said first track or tracks along said second track, each of said translatable carriages, said gripper means and said means for moving, such that after one or more articles have been placed on one layer on a pallet on one of said means for moving, the means for moving moves downward to allow for articles to be placed on the next layer with minimal or no vertical movement of said gripper. |
| 22. | A palletizing system as claimed in claim 21 wherein said means for moving moves downward to a new base level after a layer of articles has been completed on said pallet. |
| 23. | A palletizing system as claimed in claim 21 or 22 wherein the means for moving can be rotated around a vertical axis. |
| 24. | A palletizing system as claimed in claim 21 or 22 wherein the gripper can be rotated around a vertical axis. |
| 25. | A palletizing system as claimed in claim 21 or 22 wherein a conveyor bringing articles to said palletizing system incorporates an article orientating device. |
| 26. | A palletizing system as claimed in claim 21 wherein said first track is cantilevered with respect to said second track. |
| 27. | A palletizing system as claimed in claim 21 wherein a third track parallel to said second track is utilised to support said first track. |
| 28. | A palletizing system as claimed in claim 27 wherein vertical support members are provided for said second and third tracks, and said means for moving comprises a drive mechanism disposed along the vertical support members. |
| 29. | A palletizing system as claimed in claim 21 or 22, wherein said gripper means includes projecting tines for engaging the lower side of an article, and said conveying means includes a portion formed of rollers, such that the tines may interleave the rollers to engage an article. |
| 30. | A palletizing system according to claim 21, wherein said first track is driven relative to said second track from only one end of said first track. |
Field of invention
The present invention relates to palletizers which are used to collect and load articles and goods onto pallets. Background Art
Various forms of machinery have been used to perform the task of unloading boxes and goods from a conveyor, and stacking them onto a pallet for subsequent transport or storage. Robot palletizers utilise a stationary pallet table and a robotic arm which is capable of rotating and moving in the vertical direction to deposit boxes and packages in specified orientations on the pallet. Such machines require a relatively large footprint area to take into account the length of the robotic arms. The computer software required to drive such equipment tends to be complicated as one arm is utilised to perform all movements and make all adjustments.
A further difficulty with robot palletizers is that due to the rotating arm, slow movement occurs. This is because the angular momentum of the arm increases with rotational speed and this tends to put undue strain on the components. A different prior art type is layer palletizers, in which whole layers of goods are shunted together, and then placed on a pallet, which then moves downward. Such an arrangement is limited in packing patterns, and relatively difficult to change between packing patterns and different goods. Additionally, a very large footprint area is required. Gantry robot palletizers are also known in the prior art, with a gripper means which translates in three dimensions relative to a stationary pallet table. This arrangement is relatively slow, as for some pallet positions relatively large travel is necessary in three dimensions to load the pallet. It also requires load to be carried at the end of a cantilever, increasing the wear and tear on the device. A palletizer is described in US Patent 5087169 having a robotic arm which rotates around a pivot mounted upon a carriage .which carriage translates along a substantially H frame track system. The disadvantages of this system
stem from the fact that such equipment occupies a large amount of space, and that despite some reduction in footprint, the computational and engineering problems of rotating objects at the end of arms remain. The rotating arms, which can also be articulated, require clear space within which to effectively operate. The rotating arm produces high torsional loads on the sliding carriage as the load is carried away from the axis of rotation. The machinery to achieve this task is expensive and bulky. It is difficult to achieve a rigid but free moving linear axis when high torsional loads are exerted. Wherever circular movement paths are provided, wasted space results. Because of the rotational effects of the gripper means of prior art devices a rather substantial and extremely positive gripping mechanism needs to be utilised.
US patent No, 5051058 discloses a palletizer which requires very complex pallet table movements and an extremely elaborate means to mount boxes onto the pallets. This invention relies on the movement of the pallet, and complex movements prior to being placed on the pallet.
It is an object of the present invention to provide a palletizing system which has a relatively small footprint, yet is capable of a good speed of operation in use. Summary of Invention According to one aspect the present invention provides a palletizing system for placing articles from a conveying means onto a pallet comprising in combination a) at least one first track, and a second track having a longitudinal axis, said first track or tracks adapted to move along said second track; b) at least one gripper means adapted to engage at least one article to be palletized, said gripper depending from a translatable carriage means on one of said first tracks; c) means for moving at least one pallet along a vertical axis; and d) control means responsive to a predetermined instruction set for controlling the movement of said first track or tracks along said second track, each of said translatable carriages, said gripper means and said means for moving, such that after one or more articles have been placed on one layer on a
pallet on one of said means for moving, the means for moving moves downward to allow for articles to be placed on the next layer with minimal or no vertical movement of said gripper.
Preferably said means for moving at least one pallet moves downward to a new base level after a layer of articles has been completed on a pallet.
Preferably the gripper can be rotated around a vertical axis. A conveyor bringing articles to said palletizing system may incorporate an article orientating device.
Preferably a third track parallel to said second track is utilised to support the other end of said first track.
Optionally, the said palletizing system incorporates two gripper means each on their separately translatable carriage which are operatively linked to the first track. The carriages can be rigidly linked or flexibly linked, or simply controlled so as to move in unison. Another arrangement wherein there are two (or more) first tracks each with one (or more) gripper is also contemplated within the present invention.
The present invention provides a palletizer which can operate faster because the articles are driven directly along the axis of travel. Torsional loads exerted upon the track are decreased because the load or gripper is generally located near the longitudinal axis of the track which means that a lighter more economical constructions results. Further, reduced production costs tend to result because smaller sized motors and less materials are utilised because the construction which results tends to be lighter and freer.
Another advantage which results from the present invention is that it produces a very compact envelope or footprint occupied by the palletizer. A further advantage is that the ability of the pallet table to move vertically means that simpler controls and motive power connections can be utilised in the palletizer.
Because of the orientation of the tracks only very simple rotational movements need be made by the gripper. The gripper needs only to rotate through 90° to effectively load a pallet with boxes. Because no long arm is utilised centrifugal forces are low and thus vacuum grippers could be utilised
because very small centrifugal forces might be encountered.
It will be appreciated that only a short, predictable vertical movement for pick up and /or unloading, or in some arrangements no vertical movement, is required of the gripper. Brief Description of Drawings
An embodiment of the present invention will now be described with reference to the accompanying drawings in which:-
Figure 1 is a perspective view of a cantilever track mechanism embodying the present invention; Figure 2 is a perspective view of a H track mechanism embodying the present invention;
Figure 3 is a plan view of a H track mechanism which includes a further embodiment of the present invention; and
Figure 4 is a plan view corresponding to figure 2. Detailed Description
Illustrated in Figure 1 is a stationary track 10 which has a motor means 11 to translate track 20 in the direction of arrow 12. Perpendicular to arrow 12 is the direction of track 20 which carries gripper 30. The gripper 30 is moved in the direction of arrow 21 by means of motor 22. Preferably, motors 11 and 22 are electric and drive via a toothed belt type mechanism - however, any suitable drive arrangement may be used.
Also illustrated in Figure 1 is a box 40 which has been engaged by gripper 30. The track 20 is cantilevered away from track 10.
In operation a conveyor 60 delivering boxes and articles to the palletizer delivers boxes next adjacent to the palletizer. In this way a minimum of space is occupied. The palletizer moves the boxes 40 to a pallet which is located on a pallet lift table 51 which is able to lift and lower the pallet and boxes mounted thereon.
Gripper 30 illustrated is of a vacuum gripper type. However, it will be appreciated that any suitable gripping mechanism may be used within the present inventive concept.
Operation of the system is as follows. Boxes 40 to be palletized arrive on
conveyor 60 and stop at end stop 61. Gripper 30 is translated along tracks 20 and 10 to a point above conveyor 60, the collect mechanism 33 lowered, and the vacuum arrangement activated so as to engage a box 40. Box 40 is then lifted by retracting collect mechanism 33, and the gripper translated to the 5 appropriate x,y position for the box 40. As the pallet table 51 is also controlled, it is at the correct height already, and gripper 30 can be simply disengaged so as to drop box 40 a short distance into position on the pallet 57. This process is repeated until a layer is filled, at which time pallet table 51 moves down one box layer in height so that the next layer may be positioned. After all the layers are
10 filled, pallet 57 is lowered to a height suitable for a fork truck or automatic means to remove the filled pallet from the table, pallet 57 is removed, and a new pallet is loaded and raised to the appropriate height for the first layer to be loaded.
While figure 1 illustrates an embodiment of the invention which may be
15 used, it is not preferred. The use of a cantilever arm arrangement is not ideal , as it causes heavy wear on the bearings, and gives rise to some reductions in efficiency due to the high inertial load if a box is carried at the far end of the canti levered arm.
Figure 2 illustrates a preferred form of the present invention in
20 perspective, while figure 4 shows a plan view. A third track 50 allows the transverse track 20 to straddle the pallet lift table 51 and conveyor 60. The conveyor 60 delivers goods adjacent to the pallet lift table 51 thereby decreasing the amount of travel that the gripper 30 needs to make. As is indicated in Figure 2 and similarly to Figure 1 the box 40 when held by gripper
25 80 need only be rotated through 90° at most or no rotation need be made where the box will remain in the same orientation.
Gripper 80 utilises a more positive clamp mechanism than shown in figure 1. Top clamps 84 and tines 83 grip a box between them. The device works pneumatically, with tines 83 retracting for loading by operating cylinder
30 82, and clamps 84 lifting upward by operation of cylinder 85. Collect mechanism 81 and rotator 86 are similarly pneumatic in operation. Preferably, rotator has a fixed 900 rotation. The collect mechanism provides a short travel, for instance 50
mm, to allow for a box to be collected. The rotator and collect mechanisms are connected to an overall pneumatic and electrical control system for the palletizer mechanism, so that the gripper 80, pallet table 51 , and movement of the gripper along track 20 and of the track 20 along track 10 are all under common control. Of course, any other suitable gripper may be substituted.
The rotation of articles may alternatively be achieved by including a rotating feed point for the palletizer, or by allowing rotation of the pallet table itself. The lifting or collecting movement could be alternatively performed by utilising a ram arrangement at the pick up point on the conveyor 60. These mechanisms are well known in the field. The gripper arrangement shown is, however, preferred.
Pallet table 51 is preferably operated by a chain drive system via motor 75, the chains (not shown) being of conventional type and carried inside the support arms 71,72,73,74. The support arms are preferably l-form steel beams, with cosmetic facings if desired. The chain drives being largely concealed is advantageous from a safety and reliability perspective, and minimises again the space requirement. Preferably, the conveyor 60 is mounted directly onto the support 73 as shown. Preferably, the control box for the system is located in or attached to one of the support arms, and is itself remotely controlled via a PC system. Sensors of various types will also be required to ascertain or verify position, etc, as well be understood. These are preferably connected to the control box.
Track 50 is engaged by track 20 using a roller arrangement 70, as movement is controlled from motor/carriage unit 23. Preferably, roller 70 is free running, and the drive arrangement at motor/carriage unit 23 is pin jointed, so that in the event of operational faults causing the pallet table to lift too high, the gripper and track assembly simply lifts upwardly without damage. Motors 22,23 preferably drive a toothed belt arrangement so as to drive the gripper 80 and track 20. Preferably, a bracing member 26 is joined to another carriage 27 on track 10, so as to provide stability against bending during movement of track 20. It will be appreciated that for clarity, details of motors, gearboxes and drive arrangements, cable connections, and control devices have not been provided
or illustrated, as these are well known and may be purchased off the shelf from a wide variety of suppliers. Additionally, the preferred components will vary with applications (e.g expected box sizes and loads) and the facilities available on the installation site. Operation of the system is as follows. Boxes 40 to be palletized arrive on conveyor 60 and stop at end stop 61. Gripper 80 is translated along track 20, and along the axis of track 10 by movement of track 20, to a point adjacent conveyor 60, the collect mechanism 81 lowered, and the gripper 80 moved inwardly so that tines 84 interleave rollers 62. The gripper is then closed, so that clamp 84 engages a box 40. Box 40 is then lifted by retracting collect mechanism 81 , and the gripper translated to the appropriate x,y position for the box 40 to be placed on pallet 57 . The box 40 may be rotated via mechanism 86 if necessary. As the pallet table 51 is also controlled, it is at or moved to the correct height, and gripper 80 can be simply disengaged so as to drop box 40 a short distance into position on the pallet 57. This process is repeated until a layer is filled, at which time pallet table 51 moves down one box layer in height so that the next layer may be positioned. After all the layers are filled, pallet 57 is lowered to a height suitable for a fork truck or automatic means to remove the filled pallet from the table, pallet 57 is removed, and a new pallet is loaded and raised to the appropriate height for the first layer to be loaded.
The overall preferred arrangement of the embodiment of figure 2 can be better seen from figure 4. It should be noted that depending upon the gripper arrangement used, a working space may need to be provided within the palletizer to permit operation of the mechanism, and this may provide some limits to available working space within the palletizer.
Because of light weight construction, the sizes of the motors utilised to produce these movements such as rotation can be very simple and further the associated electronics and data processing required for a system embodying the present invention is much simpler due to a lesser degree of complexity in the movements. The construction of figure 2 allows for only one moving motor to be used.
As illustrated in fig. 3, a third embodiment of the present invention is
similar to that of fig. 2, except that a second gripper 30 is located on an elongated transverse track 20. Carriage 25 is somewhat bigger than the previous carriage and the elongated carriage 25 has mounted to it both grippers 30. With this embodiment the conveyor system 60 has a bifurcated terminus thus delivering two boxes to its furthest most point for simultaneous pick up by each of the grippers.
The twin or multiple gripper arrangement, which is relatively simple in implementation according to the configuration of the present invention, may be very advantageous in certain applications. Similarly, one or more extra transverse tracks parallel to track 20 could be used, if desired. Due to the relatively simple movements of the present invention, the inclusion of such facilities with a simple installation may be readily achieved. Maximum benefit is likely to be gained from this type of arrangement if the grippers and carriages are arranged or controlled so as to move in unison performing the same task in parallel, although there is no reason why they could not be separately controlled.
The present invention also lends itself to multiple bay applications, as many palletizers could be controlled by a central PC, and the design contains the necessary mechanisms within the support framework. Thus, multiple palletizers could be arranged back to back.
The foregoing describes one embodiment of the present invention and modifications by those skilled in the art can be made thereto without departing from the scope of this invention. For example the present invention can function as a de-palletizer as well as a palletizer.
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