VAN DEN BRINK, Hendrik (Prof. Bavincklaan 5, AT Amstelveen, NL-1183, NL)
| Claims 1. A method for moving products, i.e. picking up, transferring and placement thereof, in particular of packaging units such as egg boxes as well as patterns thereof, while the products (2) each comprise a substantially rectangular shape with, at least partly, an edge part (23) therearound, wherein the placement is carried out with a gripper with at least two gripping blades (13), substantially parallel to each other and rotational about correspondingly parallel axis (12a), for gripping a said product (2) on two opposite sides at the said edge parts (23), and with slightly inwardly bent gripper blade edges (14) which grip close-fittingly around the said edge parts (23), characterized in that after placement of the said products (2), on a substantially horizontal support surface, the gripper blades (13) are rotated about said axes (12a), wherein the gripper edges (13) move substantially against the top of the products (2) and simultaneously, the gripper blade edges (14) move away from and upwards relative to the edge parts, while thereupon, the gripping blade edges (14) take up a substantially vertical position with their ends against the edge part, whereupon the gripper is moved in substantially vertical direction away from the packaging unit and releases this. 2. A method according to claim 1, characterized in that upon rotation about the said axes (12a), these axes are moved substantially towards each other. 3. A method according to claim 1 or 2, wherein the gripper (1) is at least provided with a first drive (11) which is connected at a first rotation axis (11a) to said gripper blade, wherein the gripper (1) is provided with a second 1 10 drive (12) which is connected at a second rotation axis (12a) to this gripper blade (13). 4. A method according to claim 3, wherein each second drive (12) is actuated during a non-actuated condition of the first drive (11) for moving the gripping blades (13) towards each other, while an edge (23) of the product functions as gripper blade tilting point for tilting the gripping blades. 5. A method according to claim 3 or 4, wherein each first drive (11) as well as each second drive (12) are actuated when the gripper transports the product (2). 6. A gripper for moving products, in particular packaging units such as egg boxes as well as patterns thereof, wherein the gripper is provided with oppositely arranged gripping blades (13), each provided with downward extending gripping blade edges (14), with the blades (13) and respective edges (14) mutually including an angle, wherein the gripper (1) is at least provided with a first drive (11) and a second drive (12) which are both connected, at a first rotation axis (11a) or a second rotation axis (12a), respectively, to a said gripping blade (13), wherein the first and second rotation axes (11a, 12a) are parallel to each other, wherein the gripping blades (13) are each rotatable about said rotation axes, as well as mutually translatable, under the influence of said drives (11, 12). 7. A gripper according to claim 6, wherein the second drive (12) is actuatable during a non-actuated condition of the first drive (11), in particular during a movement of the blades (13) towards each other. 8. A gripper according to claim 6 or 7, wherein a said first rotation axis (11a) is located at a position which is higher than a position of a said second rotation axis (12a). 9. A gripper according to any one of claims 6 -8, provided with two gripper blades (13), as well as two first drives (11) which are connected at first rotation axes (11a) to the gripper blades (13) and two second drives (12) which are connected at second rotation axes (12a) to the blades (13). 10. A gripper according to any one of claims 6 - 9, wherein each first drive (11) is translatable by a second drive (12), in particular simultaneously with a translation of a said first rotation axis (11a). 11. A gripper according to claim 10, wherein the first drive (11) is mechanically coupled to a driven part (10b) of the second drive (12), in particular via a fixing element (10c). 12. A gripper according to claim 10 or 11, wherein the first drive (11) is hingedly coupled via a hinge to a driven part (10b) of the second drive, in particular via a fixing element (10c). 13. A gripper according to any one of claims 6 - 12, wherein each first drive (11) comprises a piston/cylinder assembly of which the piston in said non- actuated condition is freely movable relative to the cylinder. 14. A gripper according to any one of claims 6 -13, wherein each second drive (12) comprises a piston/cylinder assembly. 15. Use of a gripper according to any one of claims 6 - 14 in a method according to any one of claims 1— 5. |
PCT/NL 2011 u D O
P95029PCOO
Title: Method and gripper for moving products
The present invention relates to a method for moving products as described in the preamble of claim 1.
Such a method is known from EP930255. In this publication, it is described how egg boxes can be gripped and picked up by a particular type of gripping blade to thereupon be placed in so-called overpack boxes (outer boxes). Upon picking up and gripping, this type of gripping blade
advantageously utilizes the bottom lid construction of such egg boxes. The result of such a construction is a projecting edge around such a substantially rectangular egg box, while gripping blade edges of such a gripper can be close- fittingly clamped around these edges. It is described in particular how the gripping blades act immediately after the placement of such egg boxes. It is elucidated in detail that through rotation of the gripping blades in combination with biasing elements, the gripping blades are pushed against the inside of the outer box and thus slightly release the egg box which, prior thereto, was clamped. At the subsequent substantially vertical upward movement of the gripper, the released egg box remains in its place while the wall of the outer box which is pushed slightly outwards, will once more substantially enfold the placed egg boxes. It has appeared that such a gripper can place egg boxes in outer boxes in a highly reliable manner.
Other than described hereinabove, more and more frequently, use is made of transport on pallets whereby, on the pallet, layers of patterns of such egg boxes are placed. Most apparent is that in this way the use, and
consequently the application of such outer boxes have become superfluous. When placing egg boxes on a support surface with a gripper as described hereinabove, already placed egg boxes will be pushed aside because an outer box wall lacks. P^C_T # 1
/NL Zmi / υ J 0 »
In order to remedy such a shortcoming, the method according to the present invention is characterized in that after placement of the products on a substantially horizontal support surface, the gripping blades are rotated about axes, wherein the gripping blades move substantially against the top of the products and, simultaneously, the gripping blade edges move away from and upwards relative to the edge parts while thereupon, the gripping blade edges take up a substantially vertical position with their ends against the edge parts whereupon the gripper is moved in substantially vertical direction away from the packaging unit and releases this.
Thus, in a suitable manner, patterns of, for instance, egg boxes can be placed on top of each other and at the same time next to each other without upsetting the positioning of the adjacent boxes, in particular upon placement on pallets where layers are built up with mutually different patterns for the purpose of stability.
The method according to the invention can be defined as follows: a method for moving products, i.e. the picking up, transferring and placement thereof, in particular of packaging units such as egg boxes as well as patterns thereof, wherein the products each comprise a substantially
rectangular form with, at least partly, an edge part therearound,
wherein moving is carried out with a gripper with at least two
gripping blades, substantially parallel to each other and rotational about
correspondingly parallel axes, wherein the blades comprise blade edges which grip each product during conveyance along two wall parts extending below the edge of the product,
wherein after placement of each product on a support surface, each gripping blade is rotated towards a releasing position while using the edge of the product as tilting point. rU J / l L LM \ l ' w
According to a further elaboration, during conveyance of the product, the blade edges extend substantially parallel to opposite product wall parts, while the gripping blades which extend above the blade edges extend parallel to each other and in particular in vertical direction.
According to a further elaboration, after this rotation, in a releasing position, the blade edges extend substantially parallel to each other, in vertical direction, while the gripping blades extend parallel to opposite product wall parts. A further exemplary embodiment of the method according to the invention is characterized in that upon rotation about the axes, these axes are moved substantially towards each other.
Thus, highly advantageously, a compact drive can be built in.
fact, in this manner, the method according to the invention offers the
possibility to also use grippers for heavier and bulkier packaging units.
The invention further provides a gripper which is characterized by the features of claim 6. The gripper is configured in particular for carrying out a method according to the invention. In particular, the gripper is provided with oppositely arranged gripping blades, each provided with downward extending gripping blade edges, with the blades and respective edges mutually including an angle, wherein the gripper is at least provided with a first drive and a second drive which are both connected, at a first and a second rotation axis, respectively, to a gripping blade, wherein the first and second rotation axes are parallel to each other, wherein the gripping blades are each rotatable about the rotation axes as well as mutually translatable under the influence of the drives mentioned. The gripper can be provided with, for instance, a control for regulating the actuation of the drives. The regulation may be such that the actuation of the first gripper drive is removed during an actuation of the r l l L Di l l * u u
4 second gripper drive, while the latter drive serves for moving the grippers towards each other.
Further advantageous elaborations of the invention are described in the subclaims. In the following, the present invention will be elucidated in further detail on the basis of a drawing, in which
FIGURE 1 represents the situation just before gripping an egg box, FIGURE 2 shows the situation in which an egg box is gripped, and FIGURE 3 represents the situation at the moment an egg box has been placed and is released.
In the Figures, the same reference numerals indicate the same parts.
In the FIGURES 1, 2 and 3 an exemplary embodiment of gripping head 1 for carrying out the method according to the present invention is schematically indicated. The present gripping head comprises two oppositely arranged gripping blades 13. Each gripping blade 13 comprises at a lower end a gripping blade edge 14 (i.e. an end part); the blade edges/end parts 14 of the blades 13 are bent inward (towards each other). As follows from the drawing, the blade edges 14 of the example each include an angle with a gripping blade part extending thereabove.
In greater detail, a fixing plate 10 is shown having connected thereto a first fixing rod 10a which extends substantially downwards. Hereto is connected a second gripper drive 12, for instance a pneumatically operating piston, which is connected, at the piston side, by a second fixing rod 10b at a gripper rotation axis 12a to a gripping blade 13. To the second fixing rod 10b is further fixedly connected a third fixing rod 10c, which is connected, in turn, to a first gripper drive 11, for instance also a pneumatically operating piston. At the piston side, this gripper drive 11 is connected to a fourth fixing rod lOd which is also connected, at the other side, at a first rotation axis 11a, to the gripping blade 13 mentioned. As follows from the drawing, in this example, a first rotation axis 11a is located at a position which is higher than a position of a second rotation axis 12a. Further, each first rotation axis 11a and second rotation axis 12a are each located, during use, at levels above the product 2 to be transported. The same holds, for that matter, for the respective drives 11, 12 as such (while the second drive 12 extends at a level between the product 2 and the first drive 11). The control of these gripper drives 11 and 12 allows for both translatory movements and rotational movements of the gripping blade 13. In particular, a gripper control can regulate an actuation condition of each drive. These translatory movements take place substantially horizontally, parallel to a horizontal support surface on which products 2 are placed, while the rotational movements are carried out about the gripper rotation axes 11a and 12a.
Each product 2 has substantially a rectangular form with, at least partly, an edge part 23 therearound. In the example, the product 2 is provided on both sides with wall parts which, above the edge part 23, extend obliquely upwards (in a direction towards each other), and wall parts which, below the edge part 23, extend obliquely downwards (in a direction towards each other).
In these FIGURES, the product is a packaging unit 2, in particular an egg box having, in a known manner, nests for eggs, with a bottom part 21, with a lid part 22, and with a box edge 23, while a lower edge of the lid part snaps around a top edge of the bottom part in a manner known per se. For this snapping, sometimes, openings and matching lips are used too, which can engage over each other and into each other. In FIGURE 1, the situation is represented just before gripping of the egg box 2. Although, in the FIGURES, the attachment and drive of these gripping blades is indicated on one side only, a similar attachment and drive are also used on the other side. Both gripping blades 13 are positioned such that when simultaneously, second fixing rod 10b is drawn in and fixing rod lOd is moved outwards, the egg box 2 is gripped and can then be transported.
When following these movements, the situation of FIGURE 2 is obtained (i.e. a transport situation). In this FIGURE 2, it can be clearly recognized how a gripper blade edge 14 is placed close -fittingly around the box edge 23 and thus simultaneously clamps and carries the egg box 2 (in the drawing, the grippers 13 grip, with the blade edges 14, box wall sections which extend below the box edge 23; the blade edges 14 extend in particular substantially parallel to the opposite box wall sides, while gripper blades 13 which extend above the blade edges 14 extend parallel to each other, in particular in vertical direction). During transport, the gripping blades will remain in this position and the gripper drives 11, 12 will remain accordingly actuated.
To now place the egg box 2 without pushing away any egg boxes already present and placed, the method according to the present invention is utilized, partly represented in FIGURE 3 as one of the intermediate steps.
More particularly, after placement of the egg box according to FIGURE 2, the actuation of the first gripper drive 11 will be removed (in particular under the influence of the gripper drive). For a piston assembly this means that the piston is without pressure and that the fourth fixing rod can move freely. However, the second gripper drive 12 remains actuated (in particular under the influence of the gripper control) and in a manner such that the second fixing rod 10b is drawn in. As a result, the box edge 23 will start to act as tilting point while the gripper blade 13 does not move outwards, sideways from the egg box, and may thus possibly push away egg boxes placed adjacent thereto. In this FIGURE 3 it can be properly seen that in this manner, active rotation takes place only round the second gripper rotation axis 12a. Thus, the gripping blades 13 are moved against the top of this egg box 2 (i.e. against wall parts of the box 2 that extend above the box edge 23, in particular to positions wherein the blades 13 extend parallel to the opposite box wall sides), while the gripper blade edges 14 around the box edge 23 are moved upwards and underneath are moved away from their supporting position. The final position of the blade edges 14 upon release, as represented in this FIGURE 3, is a substantially vertical position (in that case, the blade edges 14 are
substantially paraDel to each other). From this position (i.e. a releasing position of the blades 13) the gripper head 1 will be moved upwards as a whole so that the egg box 2 is freed and released.
Further, in the FIGURES 1, 2 and 3, and in particular in FIGURE 3, it will be recognized that the axes 12a are pulled effectively towards each other substantially from two sides and are moved when the gripping blades 13 are rotated about the rotation axes 12a. In FIGURE 2, such rotation is further indicated with arrows Ra and Rb.
It will be clear to those skilled in the art that several elaborations are possible, in particular in the selection of drives, without in this manner changing the essence of this invention, rotating against the box and drawing in the gripping blades. Similar and further small modifications are understood to fall within the scope of protection of the appended claims.
Legend ..
PCT/NL Z011 / U O U H
8
1 gripper head
10 fixing plate
10a first fixing rod
10b second fixing rod
10c third fixing rod
lOd fourth fixing rod
11 first gripper drive
11a first gripper rotation axis
12 second gripper drive
12a second gripper rotation axis
13 gripper blade
14 gripper blade edge
2 egg box
21 bottom part
22 lid part
23 box edge
Ra gripper rotation direction one side
Rb gripper rotation direction other side