Load carrier conveyor unit with increased ground clearance

Description

[0001] The invention relates to a conveyor unit for conveying load carriers, and further to a conveyor device with several, in particular two, such conveyor units.

[0002] For the internal transport of goods, load carriers are regularly used that can be driven under by industrial trucks, lifted together with the goods stored on them, and then set down again at the destination after transport. A well-known example of such a load carrier is the standardized and reusable "Euro pallet."

[0003] Various types of industrial trucks are known from the prior art, which are referred to below as conveyor systems. A distinction can be made between single-part and multi-part conveyor systems. In the former, as shown, for example, in EP 2 336 075 A1, the sections of the conveyor system that travel beneath the load carrier are firmly connected to one another. Multi-part conveyor systems, as shown, for example, in DE 10 2007 046 868 A1, usually comprise a first and a second conveyor unit that are not physically connected to one another. Conveyor systems can also be differentiated with regard to their operation. On the one hand, manual or motorized operation is possible, as is the case, for example, with hand pallet trucks that are regularly used to load and unload trucks. On the other hand, autonomously operated conveyor systems are also known; see EP 2 336 075 A1 for this.A conveyor system for transporting load carriers is also known from US 2021 / 0197900 A1.

[0004] In the case of autonomously operated conveyor systems which pass completely underneath the load carriers to be transported, the clearance profile provided by the corresponding load carriers, i.e. the space available for the conveyor system when moving in or out under the load carriers parked on the ground, represents a very significant limiting factor. All components required for the function and operation of the conveyor system must be accommodated within the available height, width and length, whereby certain minimum distances in height and width must also be maintained from the load carrier in order to ensure trouble-free moving in and out. These narrow structural limits mean that in known conveyor systems of this type the ground clearance, i.e. the distance between the underside of the profile of the conveyor system and the ground orThe amount of soil must be reduced to a minimum in order to accommodate all components necessary for the function and operation of the conveyor system within the available clearance profile. However, this in turn means that conventional conveyor systems of this type cannot negotiate uneven ground, as is the case, for example, when loading and unloading trucks or driving onto loading ramps.

[0005] The object of the present invention is to provide a conveyor unit or a conveyor device with several such conveyor units, which remedy this disadvantage.

[0006] This object is solved by the subject matter of independent claim 1 and subordinate claim 10. The subclaims define preferred embodiments of the present invention.

[0007] The conveyor unit according to the invention for conveying load carriers therefore comprises a frame structure with two or more rollers rotatably mounted relative to the frame structure; a support element which can be brought into contact with the load carrier and which can be moved vertically relative to the frame structure between a raised position and a lowered position by means of a lifting device; wherein at least a part of the conveyor unit is raised or lowered together with the support element.

[0008] In other words, the conveyor unit according to the invention has a frame that can be moved on the ground with the help of ground rollers. The number of ground rollers mounted so as to be rotatable relative to the frame is preferably selected such that the conveyor unit can be stably supported on the ground by means of them. In order to enable the load carriers described above to be driven under, the conveyor unit and thus also the frame have an elongated shape with a length that is significantly greater than the width and height. The rollers can be arranged individually, in pairs, or in groups in the front or rear area of ​​the frame, so that the frame spans the central area in between. Furthermore, the rollers are mounted so as to be rotatable at least about a horizontal axis running transversely to the longitudinal axis of the frame.Additionally, individual, multiple, or even all rollers can be mounted relative to the frame so they can rotate around a vertical axis, allowing the conveyor unit to move relative to the ground with two independent translational and one independent rotational degrees of freedom. Furthermore, individual, multiple, or even all rollers can be motorized.

[0009] In addition to the frame, the conveyor unit according to the invention has at least one support element that can be raised and lowered relative to the frame, thereby lifting and lowering load carriers. One or more lifting devices are used for this purpose, providing the lifting movement and being actuated mechanically, for example. An electrically driven scissor mechanism, for example, would be conceivable, although any other suitable mechanical or hydraulic lifting mechanism would also be conceivable.

[0010] According to the invention, the frame structure has a profile underside which, in at least one partial section, has a vertical distance from a ground plane defined by the contact surfaces of the two or more rollers that is greater than the vertical distance between the remaining profile underside and the ground plane, wherein the at least one part of the conveyor unit is arranged at least partially below a partial section of the profile underside in the lowered position of the support element, and in particular is arranged above the partial section of the profile underside in the raised position of the support element. Thus, viewed in a horizontal direction, the frame has a profile whose underside facing the ground has a variable ground clearance over the extent of the frame. In other words, the profile underside is divided into several partial sections that are spaced from a ground plane by different distances.The ground level is defined by the respective areas of the ground rollers where they contact the level ground. This allows the ground clearance of the frame to be increased in critical areas to prevent unintentional contact of the conveyor unit with the ground, while non-critical areas can have less ground clearance, thus providing the necessary installation space for the conveyor unit components.

[0011] The advantage of increased ground clearance is particularly evident when transporting load carriers, as it allows the conveyor unit to negotiate uneven ground, such as thresholds or ramps. In this transport position, at least one support element is raised relative to the frame, thereby also lifting the load carrier resting on it. Of course, the conveyor unit can also move without a load carrier and with the support element raised.

[0012] The present invention has recognized that when driving under load carriers, there is no need for increased ground clearance and that the space beneath the load carrier, in particular between the underside of the frame profile and the ground, can thus temporarily serve to accommodate parts or components of the conveyor unit. This is particularly advantageous when driving under load carriers, since the conveyor unit must not exceed a certain spatial height (clearance profile of the load carrier less the minimum vertical distance between the load carrier and the conveyor unit) at this time. By lowering parts or components of the conveyor unit, in particular to below the underside of the frame profile, a larger construction volume is available for these parts or components than if these parts or components had to remain above the underside of the profile.

[0013] In summary, it can be stated that the present invention creates a conveyor unit which makes maximum use of the space volume limited by the load carrier clearance profile when driving under load carriers and, as soon as the support element is lifted together with the load carrier for transport, has sufficient ground clearance to drive over uneven ground.

[0014] In one embodiment, the profile underside of the frame structure has a section with increased ground clearance between, particularly centrally between, the floor rollers. In other words, a section with increased ground clearance can also be located centrally between the front and rear ends of the frame or conveyor unit. This makes it possible for the conveyor unit to travel over convexly curved floor sections without the risk of the frame making contact with the ground in the central area of ​​the conveyor unit or between the front and rear rollers.

[0015] According to a further embodiment, the profile underside of the frame can also have a section with increased ground clearance in at least one end section, in particular in both end sections of the frame structure or the conveyor unit. In other words, these sections can extend between the respective ends of the frame or conveyor unit and the nearest floor rollers. The increased ground clearance in these sections allows the conveyor unit to negotiate concavely curved floor surfaces without the risk of the frame or conveyor unit touching the ground at the front or rear end section.

[0016] Depending on the expected unevenness of the ground, these individual raised sections can all have the same ground clearance or different ground clearances.

[0017] The sections of the remaining profile underside with a smaller vertical distance from the ground plane can be formed in particular in the area of ​​the rollers, in particular in the area of ​​a front and a rear roller arrangement or pairs of rollers.

[0018] In a further embodiment, at least one section with increased ground clearance is shaped such that the vertical distance from the ground plane varies across the horizontal extent of the section. The profile is advantageously continuous and without sharp edges to avoid stress concentrations. Furthermore, the ground clearance can decrease toward the rollers, since the advantage of a high ground clearance becomes increasingly less apparent there. The section(s) with increased ground clearance can have a straight or curved profile in any desired manner.

[0019] In a further embodiment, the vertical distance of the at least one partial section to the ground plane may be greater than the average vertical distance between the entire profile underside and the ground plane.

[0020] At this point, it should be noted that the frame underside can be profiled transversely to the longitudinal axis of the conveyor unit, as described above, i.e., viewed horizontally and transversely to the longitudinal axis of the conveyor unit, but also in the direction of the longitudinal axis, i.e., viewed horizontally along the longitudinal direction of the conveyor unit. With floor rollers mounted so they can rotate about a vertical axis, the conveyor unit can also move transversely to its longitudinal axis, so the advantages of a profiled frame underside described above can also apply here.

[0021] To establish the transport position or to enable the passage under load carriers, parts or components of the conveyor unit can be raised or lowered by the same amount as the support element. This makes it possible to firmly connect the corresponding parts or components to at least one support element.

[0022] However, if the entire lifting path of the support element is not necessary to create sufficient ground clearance, or if more ground clearance is desired, parts or components of the conveyor unit can also be raised or lowered by a correspondingly lower or higher amount than the support element.

[0023] Furthermore, it is conceivable to raise or lower different parts or components of the conveyor unit by different amounts. The smaller the vertical distance between these parts or components and the nearest roller or roller assembly, the smaller the ground clearance required to negotiate uneven ground of a defined size.

[0024] It is generally conceivable for individual parts or components of the conveyor system to be raised or lowered to have their own drives for lifting or lowering, although these can also be raised or lowered using a lifting device provided for a supporting element. In the case of different lifting heights, only a corresponding gearbox is required.

[0025] Apart from the frame structure itself and the floor rollers which are mounted so as to rotate relative to the frame structure, it would be conceivable for all parts or components of the conveyor unit to be raised or lowered, for example for one or more sensors such as optical sensors, cameras, mechanically operated buttons and / or other suitable sensors including their data interfaces, and / or for one or more control units such as power electronics, safety technology and radio technology. This is particularly possible for sensor units which can be arranged, for example, in the respective end sections of the conveyor unit which form an overhang beyond the respective floor rollers. The same applies to an energy storage device oran accumulator for supplying the conveyor unit with electrical power and / or a control device for controlling and / or regulating the conveyor unit for autonomous load carrier transport, which can be arranged, for example, between a front and a rear floor roller arrangement.

[0026] In principle, it is also possible to raise or lower one or more drive units or parts thereof, especially if they are not located in the area of ​​the floor rollers.

[0027] A further aspect of the present invention relates to a conveyor device with several, in particular two, conveyor units according to one of the embodiments described above.

[0028] The present invention is described in more detail below using a preferred embodiment and with reference to the accompanying figures. The invention may include all of the features described herein individually or in any meaningful combination.

[0029] They show: Figure 1: a conveyor device according to the present invention, comprising two conveyor units; Figure 2: a conveyor unit according to the invention in the lowered state; Figure 3: the conveyor unit from Figure 2 in the raised position; Figure 4: the conveyor unit from Figure 2 when driving over a convexly shaped uneven ground; Figure 5: the conveyor unit from Figure 2 when driving over a concavely shaped uneven surface.

[0030] The Figure 1shows a two-part conveyor device 12 with two conveyor units 1 that are not physically connected to each other. Such autonomously operated conveyor devices are known, for example, from DE 10 2007 046 868 A1 and DE 10 2019 001 125 A1. Figure 1 further shows how the conveyor units, in the lowered state, can drive under a load carrier 11 (transport pallet / "Euro pallet") in order to subsequently lift the load carrier for transport.

[0031] The Figure 2shows schematically one of these conveyor units 1 in a lowered state, in which a load carrier 11 can be driven under. In the front and rear areas of the conveyor unit 1, a pair of rollers 3 is arranged, whereby only one roller 3 is visible at a time. The contact surfaces of the front and rear rollers define a floor plane 6, from which the lowered conveyor unit 1 has a constant distance b 2 over its entire extent. The installation spaces provided for the sensor units 7, the drive units 8, the energy storage unit 9 and the control device 10 therefore also have a distance b 2 from the floor plane 6. The same applies to the support element 4 designed as an enveloping structure, which not only has a vertical wall surrounding all parts or components of the conveyor unit 1, but also a horizontal upper side, with which it contacts the load carriers 11 to be lifted. Figure 2It is clearly visible that the low ground clearance across the entire length of the conveyor unit 1 allows maximum use of the installation space without exceeding the maximum construction height specified by the clearance profile of load carriers. However, in the lowered state of the conveyor unit 1, driving over or through uneven ground would not be possible without risking contact with the ground and consequently a loss of function / traction of the conveyor unit 1 or even damage to the conveyor unit 1.

[0032] In order to achieve sufficient ground clearance for driving over or through uneven ground despite the maximum utilization of the installation space provided by the clearance profile of load carriers 11, the present invention proposes the Figure 3The concept shown is as follows: When the support element 4 is lifted for the transport of load carriers 11 supported on the support element 4, other parts or components of the conveyor unit 1 are also lifted. In the example shown, both the energy storage device 9 and the control device 10, which are both arranged between the pairs of rollers 3, are lifted together with the support element 4 and by the same amount as the support element 4 by means of a lifting device (not shown). This creates a section 5A between the pairs of rollers 3, which section has a ground clearance b 1 that is increased compared to the original ground clearance b 2. The same is the case for the areas of the conveyor unit 1 that overhang the pairs of floor rollers 3.Here, sensor units 7 are arranged, which are also raised together with the support element 4 and by the same amount as the support element 4, in order to create areas 5B whose ground clearance increases with increasing distance from the roller pairs. In the . Figure 3 In the raised state of the conveyor unit 1, which can be seen, parts of the frame 2 emerge in the area of ​​the roller pairs 3, the distance b 2 of which from the floor level 6 is maintained, which, however, is not a hindrance when driving over or through uneven ground, as can be seen from the Figures 4 and 5 As soon as the load carrier 11 has been transported to its destination by the conveyor unit 1, the support element 4 as well as all other parts or components 7-10 previously lifted with it are returned to the Figure 2 lowered to the visible state.

[0033] The Figure 4shows the conveyor unit 1 in the raised state and when driving over a convexly curved unevenness in the floor, which lies between the roller pairs 3 above the floor level 6 (see Figures 2 and 3 ) and thanks to the increased ground clearance does not come into contact with the frame 2 of the conveyor unit 1.

[0034] The Figure 5 shows in an analogous manner how the present invention enables the passage through a concavely curved unevenness in the ground without any contact with the ground occurring in the front or rear area of ​​the conveyor unit 1.

Claims

1. Conveyor unit (1) for conveying load carriers (11), comprising - a frame structure (2) having two or more rollers (3) which are mounted so as to be rotatable in relation to the frame structure (2); - a supporting element (4) which can be brought into contact with the load carrier (11) and can be moved by means of a lifting device in a vertical direction in relation to the frame structure (2) between a raised position and a lowered position; characterised in that the frame structure (2) has a profile underside (5) which, in at least one section (5A, 5B), has a vertical distance (b1) from a floor plane (6), defined by the contact surfaces of the two or more rollers (3), which is greater than the vertical distance (b2) between the remaining sections of the profile underside (5) and the floor plane (6), and at least one part (7-10) of the conveyor unit (1) is raised and lowered together with the supporting element (4) and, in the lowered position of the supporting element (4), is arranged at least partially below a section (5A, 5B) of the profile underside (5).

2. Conveyor unit according to claim 1, wherein the profile underside (5) has the at least one section (5A, 5B) - between, in particular centrally between, the rollers (3) of the frame structure (2); and / or - in an end section, in particular in both end sections of the frame structure (2).

3. Conveyor unit according to one of claims 1 and 2, wherein the section or the remaining sections of the profile underside (5) is arranged with a smaller vertical distance (b2) in the region of the rollers (3).

4. Conveyor unit according to one of claims 1 to 3, wherein, in at least one section (5A, 5B), the vertical distance (b1) changes over the horizontal extent of the section (5A, 5B), in particular decreases towards the rollers (3).

5. Conveyor unit according to one of claims 1 to 4, wherein the vertical distance (b1) of the at least one section (5A, 5B) is greater than the average vertical distance (bm) between the profile underside (5) and the floor plane (6).

6. Conveyor unit according to one of claims 1 to 5, wherein - the at least one part (7-10) of the conveyor unit (1) is raised and lowered by the same amount as the supporting element (4); and / or - the at least one part (7-10) of the conveyor unit (1) is raised and lowered by a smaller amount than the supporting element (4).

7. Conveyor unit according to one of claims 1 to 6, wherein different parts (7-10) of the conveyor unit (1) are raised and lowered by different amounts.

8. Conveyor unit according to one of claims 1 to 7, wherein the at least one part (7-10) of the conveyor unit (1) is raised and lowered by means of the lifting device.

9. Conveyor unit according to one of claims 1 to 8, wherein the at least one part (7-10) of the conveyor unit (1) is or comprises at least one of the following elements: - a sensor unit (7) of the conveyor unit (1); - a drive unit (8) of the conveyor unit (1); - an energy storage device (9) of the conveyor unit (1); - a control device (10) of the conveyor unit (1).

10. Conveyor apparatus (12) with multiple, in particular two conveyor units (1) according to one of claims 1 to 9.