DE9400809U1 - Control and regeneration system for exchangeable pallets - Google Patents

Description

Inspection and regeneration system for exchangeable pallets

The subject of the utility model is a system for checking the quality of used pallets and processing damaged pallets in order to ensure their return to the transport and handling process.

The preferred field of application of the invention is warehouses and storage facilities that store goods on pallets, handle them and prepare them for further transport.

Current practice in warehouses (high-bay warehouses, etc.) shows that the continuous flow is often disrupted by defective pallets.

Of 100 new pallets introduced into the process, after the first handling

approx. 45% as so-called second choice pallets (warping, chipping, splintered wood) and

approx. 5% as so-called third choice pallets (broken, in need of major repairs).

In order to avoid disruptions to the storage and handling processes, the pallets are currently stacked after use and visually checked to see whether they can be reused.

These visual inspections are complex, subjective and cannot prevent disruptions to the handling process caused by damaged pallets.

The invention was based on the task of avoiding these disadvantages and of integrating the checking of the pallets for dimensional accuracy and their regeneration into an automated process.

This is achieved according to the invention by providing a control and regeneration system for used pallets of the type described in the claims.

Thanks to a system made up of several components, it is now possible to return over 95% of used pallets as first choice pallets to the transport and handling process without restricting the automatic process.

The system is characterized by a simple design, the possibility of expansion as required and low personnel costs. It is stable and can be easily installed even without a foundation.

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Further advantageous features of the invention identified in the claims and their mode of operation are explained in more detail in the following description based on the embodiment outlined in the drawing.

The drawing shows the system in side view and top view.

A stack of preferably 10 to 12 pallets to be checked (pool flat pallet according to UIC guideline 435-2/V) is placed on the pallet lifting reception 1 using a forklift. The pallet lifting reception 1 is a lifting table that can be adjusted in height continuously or discontinuously, manually or automatically. Its maximum lifting height is 1400 mm. It is accessible from three sides. A passage of 900 mm is provided to the system.

When the system is in operation, the topmost pallet is determined via limit switches (dimension setting) and is grasped, centered and pushed into the system using a pneumatically controlled slide device.

At the entrance to the test table 2, the pallet passes test flaps located in the conveyor path to check the distance between the longitudinal axis and the boards. By pushing against the pallet components, the flaps are moved from their rest position to a tilted position, generating a signal. By evaluating the signals, positional deviations resulting from twisted blocks of wood, chipping and splitting, etc. are detected. A corresponding signal causes the control device to transport the pallet further to the processing table 5. If the completion of this first test stage does not result in any complaints, the forward movement of the pallet is stopped. This is followed by a check of the dimensional accuracy of the cross beams using light sensors arranged on the side. If an error or non-conformity is detected here, a signal is sent to the control device for further transport to table 5. If the test ends without any complaints, the pallet is pushed onto the lifting table 4 at a right angle to the longitudinal axis of the system using a pneumatic slider (pneumatic cylinder with pusher) arranged at working height. The height of the lifting table 4 is manipulated using a light barrier so that the top edge of table 4 is the same as the top edge of table 2 or, if the pallets have already been pushed on, the top edge of the last pallet is the same as the top edge of table 2. During operation, the lifting table 4 is lowered step by step by the height of the pallet as more and more pallets are placed on it. To facilitate continuous pushing onto the pallets that have already been placed down, one of the two pneumatic cylinders is given a pre-travel so that the pallet is pushed on at an angle of approx. 10° and only at the end is it moved back into alignment with the base by the second cylinder running behind. When a stack of 10 to 12 pallets has been set up, a signal (horn-visual signal) is given so that an operator can remove the stack and return table 4 to its original position. If an error signal was registered in the first or second test stage, the pallet is automatically fed to the next processing stage. Lowerable rollers pick up the pallet and push it onto processing table 5. This is equipped with four eccentrically mounted vibrators that are arranged in such a way that they can act on the twisted or warped longitudinal beams and "beat" them to the passage width.

The inner vibrators have a diameter of 250 mm and a height of 100 mm and an eccentricity of 12.5 mm. With the same eccentricity, the outer vibrators have a diameter of 100 mm. The vibrators are coupled in their rotational movement so that the impact forces act simultaneously and in opposite directions. The outer and inner sides of the outer longitudinal beams or both sides of the central beam are struck simultaneously. This means that the pallet does not warp. The vibrators work continuously and knock the entire length of the pallet inside and out.

Behind them, at a distance of 500 mm, are rasp discs for the side surfaces of the longitudinal beams. They are driven by V-belts at a speed of 100 min - ¹ and are designed to remove fragments, splinters and the like. Their wear is minimal because the pallet has already been knocked into shape in the previous operation.

The lowered rollers push the pallet further to the brushing station, where wire brushes at high speed remove splinters and fibers from the previous work step. The wire brushes, like the rasp discs, are arranged outside and between the longitudinal beams. Their position in relation to the wood can be manually adjusted according to the required tolerance. The transport across the entire processing table 5 with the successive work steps of hammering (straightening) - rasping - brushing (cleaning) is carried out by the transport rollers acting from above. The last roller pushes the pallet onto the second test table 6.

Here, the dimensional accuracy and quality of the longitudinal and transverse beams are checked in the same way as in the first test station. Test flaps check the distance between the processed and cleaned longitudinal beams. If a signal A is triggered by folding down, this automatically causes further transport to the intermediate table 8. If this signal is not triggered, the pallet is stopped after leaving this test stage and checked for the dimensional accuracy of the cross beams using light sensors arranged on the side. If an error or non-dimensional accuracy is detected here, the signal B triggered causes further transport to the intermediate table 8. If neither signal A nor B is triggered, this means that the pallet is OK. It is pushed out of the system onto the lifting table 7 using pneumatic sliders at right angles to the conveying direction. The height of the lifting table is manipulated by a light barrier so that its upper edge or that of the last pallet pushed on is the same as the upper edge of the system. To ensure continuous insertion, the pneumatic cylinders are controlled at different times so that the pallet is pushed onto the lifting table 7 at an angle of approx. 10° to the longitudinal axis and, after the first cylinder has reached its end position, is straightened again by the second cylinder following behind. Both cylinders have the same stroke. The pallets are transported from the processing table 5 to the intermediate table 8 using transport rollers. The latter is equipped with a transport chain whose drive is controlled by a light barrier triggered by the approaching pallet. The damaged pallet is conveyed from the system to the lifting table 9 using this transport chain. The lifting table 9 lowers itself step by step so that the upper edge of the last pallet deposited is always the same as the working height of the system.

When the stack height is 10 to 12 pallets (as determined by the operator), a signal is sent to the operator to remove the stack. The operator uses a visual inspection to assess the further usability of these pallets, if necessary after manual adjustment. Since the number of pallets on lifting table 9 is approximately 4% of the total pallet volume, the amount of work required for this visual inspection and removing the stack is very low.

The system with a capacity of 500 pallets/8h is operated by one worker, whereby the operation is limited to the professional placement of the pallet stack on the pallet lifting reception 1 and the removal from the tables 4, 7 and 9.

Claims (12)

Protection claims 1. Control and regeneration system for exchangeable pallets, characterized in that the components - first pallet storage (1) for storing the pallets to be checked, - first inspection station (2) to check the dimensional accuracy of the pallet in the longitudinal and transverse axes, - Processing station (5) for mechanical processing of the pallet beams, - second inspection station (6) to check the dimensional accuracy of the pallet in the longitudinal and transverse axes, - second pallet storage (9) for receiving the pallets leaving the upstream system components arranged in series and linked to one another by known conveyor devices, whereby the test stations (2) and (6) have additional conveyor devices for optionally transporting the pallets transversely to the longitudinal axis of the system to adjacent pallet storage units (4) and (7). 2. Device according to claim 1, characterized in that the additional conveyor devices of the test stations (2) and (6) are controlled when the devices for checking the dimensional accuracy of the pallet do not emit an error signal. 3. Device according to claim 1, characterized in that the testing and processing stations have a working height of 1000 to 1800 mm above the foundation. 4. Device according to claim 1, characterized in that the pallet storage (1) is a lifting table arranged in the longitudinal axis of the system, which is controlled during operation so that the next pallet available rests at the working height of the system. 5. Device according to claim 1, characterized in that the pallet stores (4) and (7) are lifting tables whose height can be manipulated via light barriers. 6. Device according to claim 1, characterized in that movable flaps are arranged at the entrance to the test station (2), the tilting movement of which triggers a control signal and on the long side of which light sensors radiating perpendicular to the conveying direction are arranged to check the dimensional accuracy of the cross beams. 7. Device according to claim 1, characterized in that the processing station (5), in which three operations take place in chronological sequence, is equipped with eccentric oscillators acting on the longitudinal beams, rotating rasp disks and rotating brushes. 8. Device according to claim 7, characterized in that four oscillators are mounted eccentrically so that the impact forces exerted by them on the outer and central beams always act simultaneously and in opposite directions. 9. Device according to claim 7, characterized in that the pallet is conveyed in the region of the processing station (5) by means of transport rollers that can be lowered from above. 10. Device according to claim 1, characterized in that at the entrance to the test station (6) there are movable flaps which can be set into a tilted position by pallet parts, the tilting movement of which triggers a control signal acting on the conveyor device, and on the long side of which light sensors are arranged which emit light perpendicularly to the conveying direction. 11. Device according to claim 1, characterized in that the pallet storage (9) is a lifting table controlled by means of limit switches. 12. Device according to claim 3, 4 and 10, characterized in that the lifting height of the lifting tables (1), (4), (7) and (9) corresponds approximately to the working height of the system.