Industrial truck with a drive unit and a load unit, as well as a method for entering a closed pallet

Abstract

Industrial truck with a drive unit and a load unit, which has a load wheel lift, which has a support element and at least one load wheel for each load arm, wherein the at least one load wheel can be pivoted into an extended and a folded position via the load wheel lift and the support element supports the respective load arm in the folded position of the load wheel, wherein the support element supports the load arm when the load wheel is folded in, without the load wheel being supported on the pallet.

Description

[0001] The present invention relates to an industrial truck with a drive part and a load part, which has a load wheel lift.

[0002] A key technical problem when using a load wheel lift is driving into closed pallets which, for example, have a pallet board lying on the floor that obstructs a load wheel from entering. With the load wheel lift, the load arm is supported by a load wheel arranged at the front in the area of ​​the load arm tip. There are various options for constructing the load wheel; it is conceivable to use a single load wheel or a rocker with at least two load wheels. In order to pick up or set down the closed pallet, the load arm must be moved into the pallet pockets of the closed pallet and the load wheel must overcome the pallet board. When picking up Euro pallets on the long side, a lower cross board must also be overcome. The wheel resting on the floor must therefore climb onto the cross board when entering the pallet.Various forms of climbing aids are known from the state of the art for this purpose, which support the load wheel when driving into the closed pallet and raise it to such an extent that the height offset to be overcome from the load wheel to the pallet board is as small as possible.

[0003] EP 3 718 854 B1 discloses an industrial truck which has a step detection unit which is attached to the load arm and which detects a step as the load arm enters or exits the closed pallet. In response to the detected step element, the load arm is lowered and a load wheel is raised until a support wheel rests on the step. For entry and exit into and out of the closed pallet, a support wheel is arranged in front of and behind the load wheel in relation to the longitudinal direction of the forks. Furthermore, it is arranged that when the pallet is entered, the load wheel rests on the cross board and when the load wheel is entered or exited again from the closed pallet, the load wheel rolls on the cross board. The support wheel arranged in front of the load wheel in the entry direction serves as a climbing aid for the load wheel onto the cross board.

[0004] The invention is based on the object of improving the entry into a closed pallet in such a way that displacement or damage to the pallet when entering or exiting is avoided.

[0005] According to the invention, the object is achieved by an industrial truck having the features of claim 1 and by a method according to claim 10. Advantageous embodiments form the subject matter of the subclaims.

[0006] The industrial truck according to the invention has a drive section and a load section. The load section has a load wheel lift, which preferably has a support element for each load arm, a kinematic rod, and a load wheel lever with at least one load wheel. The at least one load wheel is preferably pivoted into an extended and a folded position on the load arm via the load wheel lever with the kinematic rod. The support element is arranged on the load arm in such a way that, in the folded-in position of the load wheel, the respective load arm is supported by the support element and the load wheel no longer has contact with the ground. According to the invention, the support element supports the load arm as it enters the pallet without the load wheel coming into contact with the pallet or a pallet crossboard. As it enters the pallet, the support wheel does not rest on the pallet or a pallet crossboard.The load wheel enters the pallet without contact with the pallet. The load wheel touches the ground only after it has completely crossed the cross-board. The support element prevents contact between the load wheel and the cross-board, and a climbing aid is unnecessary, as the load wheel does not come into contact with the pallet.

[0007] The support element is preferably equipped with at least two, three or more support rollers which support the load arm when the load wheel is folded in. The distance between the support rollers is no greater than the smallest width of the narrowest cross board in the pallet. The distance between the support rollers is determined as their center-to-center distance. In contrast to the runners on the tip of the load arm known from the prior art, the support element has support rollers arranged one behind the other with which a cross board of a closed pallet entrance can be driven over. Since the center-to-center distance of the support rollers is less than or equal to the smallest width of the cross board with the smallest width, the support element moves over the cross boards particularly evenly and with little vibration. In the following application, no distinction is made between wheels and rollers.

[0008] Preferably, the support element can also be designed as a sliding skid. With the sliding skid, the pallet cross-board can be overcome during closed pallet entry without the load wheel coming into contact with it. The length of the sliding skid can be considered its essentially horizontal section. The length of the sliding skid can, in particular, correspond to at least the smallest width of a cross-board of the pallet.

[0009] In a preferred embodiment, the support element is arranged on the load arm laterally next to the at least one load wheel. The support elements are preferably arranged on both sides of the at least one load wheel. In relation to the longitudinal direction of the load arm, this means that one support element is arranged to the left and / or one support element to the right of the load wheel. As a rule, one support element on each load arm is sufficient. The support elements can also be arranged on a side of the load arm facing away from the other load arm. In this embodiment, only one support element is provided per load arm on its outer side. Unlike a design with individual support wheels in front of and behind the load wheel, the support element with lateral support wheels offers the advantage that a cross board can be driven over with the support rollers without the load wheel having to be placed on the cross board and travel on it.

[0010] In a preferred embodiment, at least one support roller is arranged in front of and behind the at least one load wheel relative to the fork's longitudinal direction. When retracting or retracting the vehicle, the entire distance can be covered without the load wheel resting on the crossboard. [SM1] if the distance between the support rollers is less than or equal to the width of the crossboard. A skid section can also preferably be provided on the support element for support, in the event that, for example, one of the support rollers loses contact with the crossboard.

[0011] In a preferred embodiment, the load arm is equipped with a U-shaped profile in the area of ​​the load wheel, and the load wheel, in its folded position, fully or partially engages the U-shaped profile of the load arm. In this way, the support element is placed on the crossboard.

[0012] The support element preferably has a length that is greater than the largest distance between two cross boards in the direction of entry. Preferably, the support element is longer than the first distance in the direction of entry between a pallet board and a center board of a pallet suitable for the industrial truck, for example, greater than 227.5 mm. This allows the support element to be moved from one cross board to the next with standardized pallets without having to unfold the load wheel to overcome the distance between the cross boards.

[0013] The object of the invention is also achieved by a method for driving into a closed pallet with an industrial truck, which has the features of claim 10. The closed pallet has at least one pallet pocket into which the two forks of the industrial truck are inserted in order to lift or set down the pallet. The forks of the industrial truck each have a support element extending in the longitudinal direction of the forks. According to the invention, the load part of the industrial truck moves to a first lifting height at which the forks can be moved into the at least one pallet pocket at least almost without contact. After the load has been moved in, the load part is lowered to a second lifting height when at least a section of the support element is located above a pallet board, so that the support element touches the pallet board.The pallet board defines the pallet pocket on the side facing the base. The load wheels are then raised into a folded position in which the load wheels do not come into contact with the pallet board or any other section of the closed pallet. The forks are then moved into the pallet pockets with the load wheels folded in, so that the forks are supported on the pallet boards by the support elements and the load wheels do not support the forks on the pallet boards. The forks are therefore moved into the pallet over the support elements and support on the pallet by the load wheels is not necessary. In a subsequent step, the load rollers are folded down and the pallet is raised to transport height when the load wheels are in a predetermined intermediate area that is free of pallet boards.This means that the load wheels are folded out so that the pallet can be lifted using the forks.

[0014] A particularly preferred embodiment of the industrial truck according to the invention is described below with reference to the figures.

[0015] They show: Fig. 1A - D three different height positions for an automatically guided industrial truck, Fig. 2A - G the lifting process for the vehicle according to the invention on a closed pallet with a center board and Fig. 3A - E the lifting sequence when entering a closed pallet without a center board.

[0016] The Fig. 1A - D show a side view of an industrial truck 10 designed as a self-propelled AGV (automatic guided vehicle). The industrial truck 10 has a drive section 12 with a steered and driven wheel 14. The load section has load arms 18 and a lifting device 16. A kinematic rod 17 is actuated via the lifting device 16. A load wheel lever 20, which carries a load wheel 22 at its free end, is positioned via the kinematic rod 17. The illustrated embodiment has one load wheel 20, but vehicles with two load wheels arranged on a centrally mounted rocker are also possible.

[0017] Fig. Figure 1A shows the vehicle with the load arms 18 raised during its empty run. The lifting height H from the top of the load arm to the ground is, for example, 250 mm. Fig. 1B shows the industrial truck 10 with a load 24 picked up.

[0018] Both during empty travel and when traveling with a load, the industrial truck is controlled by a laser scanner 26. The laser scanner 26 scans the surroundings of the vehicle at the level of the scanning plane 28 to avoid collisions and control the movement of the vehicle. As shown in Fig. As shown in Figures 1A and B, the scanning plane 28 is located below the raised load arms 18 so that the laser scanner 26 has a clear view.

[0019] Fig. 1C shows the lowered load arms 18 entering a pallet 30. The pallet 30 has two cross boards 32 and 36 and a middle board 34. The load arms are at the entry height in Fig. 1C is usually lowered to a height of 95-110 mm, whereby a tolerance of + / -5 mm for the height of the lowered fork is sufficient in practical application.

[0020] The basic idea of Fig. The pallet entry shown in Figure 1C consists in the vehicle entering the pallet opening without contact and then placing its front support roller on the first cross board in order to continue moving into the pallet with the aid of the support element and its support rollers. The support element can be designed as a roller conveyor with which the load arms roll over the cross boards 32, 36 and also the center board 34. As shown in the Fig. 2 and Fig. As shown in Figure 3, the load wheels are folded into the load arms so that they do not come into contact with the pallet. The roller conveyor of the support element is a continuous roller holder that can be attached to the load arm and carries the support rollers.

[0021] Fig. 2A and Fig. 2B shows the lifting sequence when entering a closed pallet with a center board 34. In the illustrated pallet 30, the center board 34 consists of three partial boards arranged parallel to each other in the center of the pallet. The cross boards 32 and 36 are significantly wider than the partial boards of the center board 34. Fig. Figure 2A shows the situation in which the vehicle 10 approaches the pallet 30. The scanning plane 28 has a height that is less than the top edge of the pallet 30. The pallet is detected via the scanning plane 28, as is the distance of the industrial truck 10 from the pallet 30.

[0022] Fig. Figure 2B shows how the vehicle has assumed its entry height for the pallet entry.

[0023] Fig. Figure 2C shows how a tip 38 of the load arm moves into the pallet without contact. In the detailed view from Fig. The support element 40 is clearly visible in Figure 2C. The support element 40 has seven support rollers 42A-G (for clarity, only the support rollers 42A, B, and G are labeled in the figure). The support rollers 42 protrude slightly beyond a lower edge 44 of the load arm. The load arm tip 38 is retracted into the pallet opening until at least the first support roller 42G, located at the front in the entry direction, is above the cross board 32.

[0024] Fig. Figure 2D shows the following situation, where the first support roller 42G is located above the cross board 32. By lowering the lifting mechanism, the load arm 18 is lowered and the support roller 42G rests on the cross board 32.

[0025] Fig. Figure 2E shows the fully folded load wheel 22. In this case, the load wheel 22 is unloaded, and the load is carried by the support wheel 42G. The load wheel 22 is folded in by further lowering the lifting element, which allows the load wheels to be folded in via a lifting kinematic. If the support wheel 42G is lowered, the vehicle can drive further into the pallet without using the load wheel. Fig. 2E shows the situation in which the load wheel is fully retracted and the support roller 42G takes over the load.

[0026] Fig. Figure 2F shows how the vehicle continues to drive into the pallet. It can be seen that the load wheel 22 remains folded in. The support element 40 with its roller conveyor rolls from the transverse board 32 to the center board 34 and from there to the second transverse board 36. The support element with its support rollers is designed to be exactly long enough, with respect to its longitudinal extension in the drive-in direction, to allow full entry into the pallet without using the load wheel.

[0027] Fig. Figure 2G shows the situation in which the load wheel 22 is unfolded between the second transverse board 36 and the center board 34 facing the entry direction. The pallet 30 is thus raised to driving height, and the scanning plane 28 is again free to move the vehicle reliably.

[0028] Once the vehicle has reached its target position, the Fig. 2 in reverse order. This allows the vehicle to be removed from a pallet with the load wheel folded in and the vehicle being moved exclusively by the support element and the support rollers over the cross and center boards.

[0029] The Fig. Figure 3 shows the lifting sequence for a closed pallet without a center board. Such pallets without a center board are, for example, CHEP pallets with a lengthwise entry. On a stringer pallet, commonly used in the USA, the narrowest cross board is 3.5 inches wide, and the shortest distance from the cross board to the center board is 9.5 inches or 10 inches. For a Euro pallet, the minimum cross board width is 100 mm, and the distance from the first cross board to the center board is 227.5 mm. This results in a maximum distance for the support wheels of 100 mm and a minimum length for the support element of approximately 230 mm. Fig. 3A shows the retraction of the load arm tip 38 into the pallet. In Fig. 3B, the load arm is placed on the front cross board 32. The vehicle now moves into the pallet over the entire length of the support element 40 (compare Fig. 3B). Since there is no center board, the load wheel 22 is unfolded until the load arm 18 can rest on the unfolded load wheel 22. The load wheel 22 is unfolded before the end of the support element 40 is reached when driving into the pallet. The vehicle 10 then drives further into the pallet on the load wheel 22 until the lifting position is reached and, as shown in Fig. 3E, the pallet can be lifted. In the raised position Fig. 3E, the scanning plane 28 is released again. Once the target position for the pallet 30 is reached, the Fig.3 steps in reverse order to lower the pallet and pull the vehicle out of the pallet. List of reference symbols 10 industrial trucks 12 Drive part 14 wheels 16 Lifting device 17 Kinematic rod 18 Load arm 20 load wheel levers 22 cargo bike 26 laser scanners 28 scan plane 30 pallets 32 cross board 34 center board 36 cross board 38 Load arm tip 40 support element 42 support rollers 44 lower edge of the load arm QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 3 718 854 B1

[0003]

Claims

[1] Industrial truck (10) with a drive and a load part (12), which has a load wheel lift (16) which has a support element (40) and at least one load wheel (22) for each load arm (18), wherein the at least one load wheel (22) can be pivoted into an extended and a folded position via the load wheel lift and the support element (40) supports the respective load arm (18) in the folded position of the load wheel (22), characterized by that the support element (40) supports the load arm (18) when it enters a pallet when the load wheel (22) is folded in, without the load wheel resting on the pallet. [2] Industrial truck (10) according to claim 1, characterized by that the support element (40) has at least two support rollers whose distance is smaller than the smallest width of the narrowest cross board in the pallet. [3] Industrial truck (10) according to claim 1 or 2, characterized by that the support element (40) has a sliding skid. [4] Industrial truck (10) according to one of claims 1 to 3, characterized by that the support element (40) is arranged on the load arm (18) laterally next to the at least one load wheel (22). [5] Industrial truck (10) according to claim 4, characterized by that the support elements (40) are each arranged on a side of the load arm (18) facing away from the other load arm (18). [6] Industrial truck (10) according to one of claims 1 to 5, characterized by that the support element (40) is arranged to the left and right of the at least one load wheel (22) with respect to a longitudinal direction of the load arm (18). [7] Industrial truck (10) according to claim 2, characterized by that at least one support roller (42) is arranged in front of and behind the at least one load wheel (22) in relation to the fork longitudinal direction. [8] Industrial truck (10) according to one of claims 1 to 7, characterized bythat the load arm (18) has a U-shaped profile in the area of ​​the load wheel (22) and the load wheel (22) in its folded position is fully or partially immersed in the U-shaped profile of the load arm (18). [9] Industrial truck (10) according to one of claims 1 to 9, characterized by that the support element (40) has a length which is greater than the first distance in the entry direction between a pallet board (32) and a center board (34) of a pallet (30) suitable for the industrial truck (10). [10] Method for driving into a closed pallet with an industrial truck, wherein the closed pallet has at least one pallet pocket and the industrial truck has a height-adjustable load part with two forks, each of which has a support element extending in the longitudinal direction of the fork, characterized by the steps: - Moving the load part to a first lifting height at which the forks can be moved into the pallet pocket at least almost without contact; - lowering the load part to a second lifting height when at least a portion of the support element is located above a pallet board so that the support element touches the pallet board; - Raising the load wheels to a folded position; - Driving into the pallet pockets with the load wheels folded in, so that the forks are supported by the support elements on the pallet boards and the load wheels do not support the forks on the pallet boards; - Folding down the load rollers and raising the pallet to transport height when the load wheels are in a predetermined intermediate area that is free of pallet boards. [11] Method according to claim 10, characterized bythat the industrial truck is designed according to one of claims 1 to 9.

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