OVERHEAD LOADING AND UNLOADING SYSTEM, AND METHOD

Abstract

An overhead loading and unloading system (1) and method for handling pallets (2). The system comprises a pickup station (3), a loading station (4), a storage station (5) for storing protective sheets (S), and an automatically controlled linear gantry robot (6). The gantry robot comprises a robot arm (12) provided with a gripper (13) comprising forks (23) for handling the pallets and a vacuum gripper (24) for handling the protective sheets. The robot arm transports the pallets on the forks from the pickup station to the loading station and stacks the pallets in several layers (L). The robot arm implements the vacuum gripper for placing the protective sheets between the stacked layers.

Claims

1. An overhead loading and unloading system (1) for handling pallets (2) on which material is stacked, and the system (1) comprises: a pickup station (3); a loading station (4); an automatically controlled linear gantry robot (6); an overhead robot arm (12) of the gantry robot (6) movable in three axis (X, Y, Z); a gripper (13) mounted to the overhead robot arm (12); a storage station (5) for storing protective sheets (S); characterized in that the gripper (13) is provided with forks (23) for handling the pallets (2) and a vacuum gripper (24) for handling the protective sheets (S); and the robot arm (12) is configured to transport the pallets (2) on the forks (23) of the gripper (13) from the pickup station (3) to the loading station (4), and is configured to stack the pallets (2) in at least two layers (L) one on top of the other; and the robot arm (12) is configured to pick up the protective sheets (S) from the storage station (5) by means of the vacuum gripper (24) and is configured to place the protective sheets (S) on a first layer (L1) of the pallets (2) prior stacking a second layer (L2) of the pallets (2) on the first layer (L1).

2. The system as claimed in claim 1, characterized in that the gripper (13) is of a dual-type comprising the forks (23) and the vacuum grippers (24) that are selectively operable by turning the robot arm (12) around vertical Z-axis.

3. The system as claimed in claim 1, characterized in that the vacuum gripper (24) is turnable (T2) between a horizontal operational position (OP) and a vertical home position (HP) in relation to turning axis (26) by means of at least one actuator (27).

4. The system as claimed in claim 1, characterized in that width of the forks (23) of the gripper (13) are automatically adjustable in accordance with the pallets (2) and under control of a control unit (CU) of the system (1).

5. The system as claimed in claim 1, characterized in that the linear gantry robot (6) comprises: two overhead rails (8) mounted on fixed vertical supports (9); a transverse bridge (10) supported movably to the rails (8); a trolley (11) supported to the bridge (10) and being movable in longitudinal direction of the bridge (10); and wherein the robot arm (12) is mounted to the trolley (11).

6. The system as claimed in claim 5, characterized in that the transverse bridge (10) of the gantry robot (6) has a lattice type structure.

7. The system as claimed in claim 1, characterized in that the pickup station (3) is a conveyor (15) on which the pallets (2) are transported from a production line to a cell (7) comprising the disclosed overhead loading and unloading system (1).

8. The system as claimed in claim 1, characterized in that the loading station (4) is a transport platform (16).

9. The system as claimed in claim 1, characterized in that the storage station (5) is a transport platform (17).

10. The system as claimed in claim 1, characterized in that the loading station (4) is provided with a lifting unit (20) for moving the pallets (2) vertically so that the first, second and following layers (L) can be stacked at the loading station (4) on a same stacking level (LS).

11. A method for handling pallets (2) on which material is stacked, the method comprises: implementing an overhead linear gantry robot (6) for transporting the pallets (2) from a pickup station (3) to a loading station (4); and mounting protective sheets (S) on the pallets (2) at the loading station (4); characterized by using in the gantry robot (6) a dual gripper (13) whereby handling of the pallets (2) is executed with forks (23) of the gripper (13) and handling of the protective sheets (S) is executed with a vacuum gripper (24); loading the pallets (2) at a loading station (4) in at least two layers (L) one on top of the other; and mounting protective sheets (S) between the layers (L) of the pallets (2).

Description

BRIEF DESCRIPTION OF THE FIGURES

[0038] Some embodiments are described in more detail in the accompanying drawings, in which

[0039] FIG. 1 is a schematic perspective view of an overhead loading and unloading system,

[0040] FIG. 2 is a schematic top view of an overhead loading and unloading system,

[0041] FIG. 3 is a schematic side view of an overhead loading and unloading system,

[0042] FIG. 4 is a schematic side view of a lifting unit of a loading station, and

[0043] FIGS. 5-7 are schematic views of a robot arm provided with a dual-type gripper.

[0044] In the figures, like reference numerals identify like elements.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

[0045] FIG. 1 discloses an overhead loading and unloading system 1 for handling pallets 2 on which material is stacked. The system 1 comprises a pickup station 3, a loading station 4, and a storage station 5 for storing protective sheets S. There is also an automatically controlled linear gantry robot 6. The pickup station 3, loading station 4, storage station 5 and the gantry robot 6 may form a work cell 7. Layout of the work cell 7 may be arranged so that the loading station 4 is located centrally, and the pickup station 3 and the storage station are located on opposite sides of the loading station 4. Then transport distances of the gantry robot 6 may be short. Operating area of the gantry robot 6 covers the entire work cell 7 and may thereby be relatively large. The gantry robot 6 comprises two overhead rails 8 mounted on fixed vertical supports 9. A transverse bridge 10 is supported movably to the rails 8 and is provided with a trolley 11 movable in longitudinal direction of the bridge 10. An overhead robot arm 12 is mounted to the trolley 11. The robot arm 12 is provided with a gripper 13. The bridge 10 is movable linearly along horizontal X-axis, the trolley 11 is movable linearly along horizontal Y-axis, and the robot arm is extendable and retractable linearly along vertical Z-axis. Then the robot arm 12 and its gripper 13 are movable linearly in three axis. Further, the robot arm 12 can be turned around the Z-axis so that the gripper 13 can be orientated to desired direction.

[0046] The bridge 10 of the gantry robot 6 has a lattice type structure and is provided with two lattice beams 14 comprising parallel longitudinal elements united by diagonal elements. In an alternative solution the bridge may be a conventional beam structure.

[0047] The pickup station 3 is a conveyor 15 on which the pallets 2 are transported from a production line to the work or robot cell 7. An arrow A indicates transport direction of the conveyor 15 The conveyor 15 may be a roller conveyor, for example. In Figures the conveyor 15 is shown in a highly simplified manner for clarity reasons. In an alternative solution there may be a movable platform or vehicle instead of the conveyor.

[0048] The loading station 4 is a transport platform 16, which may comprise wheels for towing by means of truck, or the transport platform may be a lifting trailer, for example. The storage station 5 indicates generally an area wherein the protective sheets S can be brought. For facilitating logistics, the storage station 5 may comprise a transport platform 17 on which the protective sheets S may be stacked to form piles 18 of protective sheets S. Alternatively, the transport platform 17 may be arranged to carry several pallets on which the protective sheets S are stacked. A further possibility is to transport separate pallets with the piles 18 of protective sheets S to the storage station 5 by means of fork trucks of automatically guided transport vehicles, for example.

[0049] The gripper 13 is provided with forks for handling the pallets 2 and a vacuum gripper for handling the protective sheets S. The forks and the vacuum gripper are shown in FIGS. 5-7. The robot arm 12 transports the pallets 2 on the forks of the gripper 13 from the pickup station 3 to the loading station 4. The robot arm 12 can stack the pallets 2 two layers L1 and L2 one on top of the other. The robot arm 12 can pick up the protective sheets S from the storage station 5 by means of the vacuum gripper and places the protective sheets S on a first layer L1 of the pallets 2 before stacking a second layer L2 of the pallets 2 on the first layer L1. The stacking of the pallets 2 on the second layer L2 can be executed by using similar pattern of the pallets as in the first layer L1, or alternatively, the stacking pattern may be different in the second layer L2 for improving stability, for example. The turning feature of the robot arm 12 facilitates the handling of the pallets and allows also use of different patterns when placing the pallets 2 on the layers L1, L2. In some cases the number of the layers may be three or even more. It is also possible to implement different placing patterns and orientations for the protective sheets S.

[0050] A control unit CU is arranged to control operation of the system 1. The control unit CU may communicate with a process control system of a production plant and can control the gantry robot 6 based on received data.

[0051] FIG. 2 discloses the system 1 shown in FIG. 1 from above. The robot arm 12 is placing a first pallet on the first layer L1 covered by the protective sheets S. The conveyor 15 transports the pallets 2 from a production plant 19, storage, transport system, or any other source.

[0052] In FIG. 3 the system 1 shown in FIGS. 1 and 2 is placing a pallet 2 to form a second layer L2 on a first layer L1 of pallets 2. As can be seen there are protective sheets S between the layers L1 and L2.

[0053] FIG. 4 discloses in a simplified manner that the loading station 3 may be provided with a lifting unit 20 for moving the pallets 2 vertically so that the first, second and following layers can be stacked at the loading station 3 on a same stacking level LS. The stacking level LS may correspond to a floor level or may be selected to be any suitable level. The lifting unit 20 may comprise a lifting apparatus and needed mechanical support structures. The lifting unit 20 may be placed into a pit 21 provided on a floor. In this embodiment, the loading station 3 may comprise movable platform 22 on which the pallets 2 can be stacked by means of a robot arm 12.

[0054] FIGS. 5-7 disclose a gripper 13 which is of a dual-type comprising the forks 23 and a vacuum gripper 24 that are selectively operable by turning T1 the robot arm 12 around vertical Z-axis. Then the robot arm 12 can turn T1 the gripper 13 and select which of the two handling elements 23, 24 are used. The forks 23 and the vacuum gripper 24 are mounted to a body 25 of the gripper 13 and are facing into opposite directions relative to each other. The vacuum gripper 24 has two selectable positions. In FIGS. 5 and 6 the vacuum gripper 24 is in a vertical home position HP and in FIG. 7 in a horizontal operational position OP. The vacuum gripper 24 is turnable T2 between the operational position OP and the home position HP in relation to turning axis 26 by means of at least one actuator 27. The vacuum gripper 24 comprises a frame with at least two turnable frame parts 28 each provided with at least two suction elements 29.

[0055] Further, the forks 23 can be moved M laterally so that relative position of the forks 23 can be widened and narrowed. The gripper 13 may comprise one or more actuators 30 for adjusting the position of the forks 23.

[0056] The drawings and the related description are only intended to illustrate the idea of the invention. In its details, the invention may vary within the scope of the claims.