ROBOT CELL FOR SEPARATING A NAILED PALLET PART FROM A PALLET

Abstract

The invention concerns a robot cell (1) comprising a multi axis robot arm (3), which terminates in a gripper (4) arranged to handle a pallet (2), and a sawing device (10), which is arranged to separate a nailed pallet part from a pallet (2) handled by said gripper (4). The sawing device (10) comprises a saw blade immersed in a liquid bath, which is contained in a trough (11) of the sawing device (10), such that separation of said nailed pallet part is performed in a liquid environment.

Claims

1. A robot cell comprising a multi axis robot arm, which terminates in a gripper arranged to handle a pallet, and a sawing device. which is arranged to separate a nailed pallet part from a pallet handled by said gripper, said sawing device comprises a saw blade immersed in a liquid bath, which is contained in a trough of said sawing device, such that separation of said nailed pallet part is performed in a liquid environment.

2. The robot cell according to claim 1, wherein said saw blade is arranged stationary in said trough.

3. The robot cell according to claim, wherein said trough is elongate and said saw blade is arranged in a central part thereof

4. The robot cell according to claim, wherein said saw blade is a circular saw blade and said trough has a length exceeding twice a maximum pallet length.

5. The robot cell according to claim 1, wherein a baffle is horizontally arranged in said trough, said baffle having a central orifice, through which an upper part of said saw blade extends to perform said separation.

6. The robot cell according to claim 5, wherein said baffle is shorter than said trough , such that a circulating liquid stream surfaces from below said baffle through an inlet upstream of said saw blade at a first end of said trough and dives below said baffle through an outlet downstream of said saw blade at a second end of said trough.

7. The robot cell according to claim 6, wherein a belt conveyor is arranged to pick up a floating, separated pallet part of a pallet at said second end of said trough and to move it away therefrom.

8. The robot cell according to claim 7, wherein a scraper is arranged to free a bottom strand of said belt conveyor from wet, adhering saw dust outside of said trough.

9. The robot cell according to claim 7, wherein said belt conveyor comprises a belt made of a liquid pervious mesh material.

10. The robot cell according to claim 1, further comprising a cutting device, which comprises knives and is arranged alongside said sawing device in order to separate another nailed pallet part from a pallet handled by said gripper.

Description

BRIEF SUMMARY OF THE DRAWINGS

[0020] In the schematic drawings FIG. 1 is an overall perspective view showing a robot cell according to a preferred embodiment of the invention, and

[0021] FIG. 2 a perspective view of just a sawing device of the robot cell of FIG. 1.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0022] In the following a preferred embodiment of the present invention is described with reference being had to the accompanying drawings, in which like reference numbers are used for like parts in both drawing figures.

[0023] In the overall view of FIG. 1 reference number 1 generally depicts a robot cell which is arranged to handle one pallet at a time. However, as the drawings are schematic, two pallets, both enumerated 2, are shown in FIG. 1 in different positions. A first pallet 2, which is held by a gripper 4 of a multi axis robot arm 3, is shown centrally in a transition position, while a second pallet 2 is shown to the left arranged in a cutting device 5, where it could be placed and held by the robot arm 3 in order to have knives 6 of the cutting device 5 cut and remove chosen parts of the pallet 2. The cutting device 5 is essentially known from WO 2012/067581 A1 and therefore not described in further detail.

[0024] In FIG. 1, immediately to the right of the robot arm 3, a sawing device generally depicted 10 is shown. It will be described in detail below when dealing with the contents of FIG. 2. For now it suffices to note that it comprises a trough 11, which is to hold a liquid and from which a belt conveyor 20 rises towards a discarding bin 21 arranged behind the trough 11 in order to take up waste material provided by the belt conveyor 20.

[0025] Far right in FIG. 1 a liquid reservoir 22 is shown, which by a conduit 23 is connected to the trough 11. The purpose of the reservoir 22 will also be described below.

[0026] As can be seen in FIG. 2, the sawing device 10 comprises a stand 12, which supports the trough 11 mentioned before. The trough 11 is elongate and comprises a horizontal baffle 13, which divides the trough into a top portion above the baffle 13 and a bottom portion below the baffle, none of these portions being depicted in FIG. 2. Depicted is instead a central orifice 14 in the baffle 13, which connects said top and bottom portions and houses a circular saw blade 15. The saw blade 15 runs in parallel with the elongate trough 11 and is rigidly mounted on a shaft 16, which runs transversely of the trough 11. Said shaft 16 and hence the saw blade 15 are rotated by an electric motor 17 arranged on the stand 12 outside of the trough 11 and sealed in relation to the trough 11 by means of a liquid tight radial seal of a per se known and therefore not illustrated kind.

[0027] At the far end in FIG. 2, the trough comprises a projecting portion 18, which houses a first, lower end of the belt conveyor 20 mentioned before. Said first end is arranged essentially in level with the baffle 13, which terminates just in front of the belt conveyor 20, that is does not extend along the entire trough 11. At the opposite end of the trough 11 the baffle 13 does not either stretch all the way but terminates slightly before the baffle end in question. Thus a liquid circulation path is opened, which can form a liquid stream on top of the baffle 13 running towards the belt conveyor 20 and below the baffle 13 running away from the belt conveyor 20.

[0028] The belt conveyor 20 comprises a belt 24 made of a liquid pervious material, such as a metal mesh. The belt 24, which runs about first and second rollers (not depicted), forms a top strand, that is the belt part shown in FIGS. 1 and 2, and a bottom strand, which is opposite to said top strand but not illustrated in the drawings. Shown, however, is a minor part of a scraper 25, which is arranged to free said bottom strand of the belt 24 from waste material adhering thereto, wherein said scraper 25 is arranged such that freed waste material is dropped into the discarding bin 21.

[0029] Having described essential features of the robot cell 1 above, below the purpose and function of the robot cell 1 as well as some further details will be described to further elucidate the present invention.

[0030] As indicated in the preamble, the purpose of the robot cell 1 is to render it possible to separate chosen defective parts from a pallet 2. To this a pallet 2 in a per se known way is gripped by the gripper 4 of the multi axis robot arm 3 and introduced into the robot cell 1. Inside the robot cell 1 one can choose either to use the knives 6 of the cutting device 5 or the circular saw blade 15 of the sawing device 10 or both for the separation action. In any case the pallet 2 is handled by the gripper 4 of the robot arm 3, which is to say that it is turned, held or moved to enable separation of the chosen defective parts.

[0031] When the separation action comprises use of the sawing device 10, the parts of the pallet 2 to be separated from the pallet 2 are turned downwards and a first joint of a defective part with the remainder of the pallet 2 is aligned with the saw blade 15, which according to the present invention is totally immersed in a liquid bath contained in the trough 11 of the sawing device 10. Then the pallet 2 aligned in that way is moved by the robot arm 3, such that separation of the defective pallet part is altogether performed in a liquid environment. By this no swirling around saw dust is created, no sparking is to be feared even when cutting nails, screws or staples, and noise is lowered substantially.

[0032] In order to provide for smooth operation, the trough 11 has a length which exceeds two times a maximum pallet length. In that way and by placing the saw blade 15 in a central part of the trough 11, it is rendered possible to perform a cut along the entire length of a pallet 2 in a single sweep, which runs away from the belt conveyor 20 because the saw blade 15 is turning towards it. As soon as a part is separated, it is floatingly entrained by the liquid circulated through the trough 11 and by means of a circulation pump assembly 26 flushed towards the belt conveyor 20. There the separated part and saw dust dissolved in the liquid are picked up and discarded into the discarding bin 21, wherein the scraper 25 is used to remove saw dust adhering to the belt 24 and excessive loss of liquid is avoided thanks to choice of a liquid pervious mesh material for said belt 24.

[0033] However, from time to time liquid (generally water) has to be replenished in order to keep the saw blade safely immersed. To this a liquid reservoir 22 has turned out to be beneficial, because it can be used not only for replenishing purposes, but also to hold all the liquid of the trough 11 when it has to be emptied totally out of service reasons, e.g. when the saw blade 15 has to be replaced. In that way, and by preferably arranging a filter device (not depicted in the drawings) in the circulation pump assembly 26, liquid consumption can be minimized.

[0034] The person skilled in the art can readily find out which device (cutting device 5 or sawing device 10) to use best for a separation action, which is not only dependent on the placement of a pallet part to be separated, but also on the type of pallet at hand, such as an EUR-pallet or a perimeter pallet, which is why a robot cell 1 according to the preferred embodiment comprising both devices 5 and 10 is considered extra advantageous.