Unmanned transport vehicle with payload lifting equipment

Abstract

The invention relates to an unmanned transport vehicle (1), in particular an automatically guided transport vehicle, in particular a material transport vehicle in a factory, for transporting a payload, which transport vehicle has a payload lifting device (2). In order to achieve a particularly inexpensive and at the same time rigid and efficient construction of the lifting device (2), according to the invention, the lifting operation is carried out by an eccentric drive.

Description

Technical Field

[0001] The invention relates to an unmanned transport vehicle, in particular an automatically guided transport vehicle, preferably an autonomous automatically guided transport vehicle, for transporting a payload. Such vehicles are usually used as so-called industrial trucks or material transport vehicles in production plants, for example for transporting specific payloads in a warehouse or from a warehouse to a production line, while preferably navigating autonomously. In the case of such a transport vehicle, the load can consist directly of the payload itself and a payload carrier (e.g. a rack, a roller trolley, etc.) on which the payload can be loaded separately. The purpose here is that the transport vehicle can travel under such a payload carrier, independently lift the payload carrier, transport the payload carrier to the destination and put the payload carrier down again there. For this purpose, the transport vehicle is equipped with an integrated lifting device. Background Art

[0002] A number of different solutions for implementing the lifting function are known from practice. In order to be able to lift large loads quickly and accurately, the lifting devices require high stiffness and powerful motor configurations, with a correspondingly high demand for electrical energy, thus requiring higher weight, larger batteries, higher costs or shorter travel ranges.

[0003] For example, DE 10 2013 013 438 A1 discloses a transport vehicle whose lifting function is implemented by means of a plurality of different thrust and lever devices, which, due to their design principles and rigidity requirements, have a high system weight and require a large amount of structural space.

[0004] EP 102706 A1 discloses another transport vehicle whose lifting device consists of a ball screw drive which is complex and relatively expensive to manufacture. Summary of the invention

[0005] Against this background, the object of the present invention is to provide a transport vehicle with a lifting device which can be constructed as cost-effectively as possible and at the same time is as rigid and efficient as possible.

[0006] This object is achieved by the combination of features as defined in the independent claims. Further embodiments and developments of the invention emerge from the dependent claims as well as from the following description and the drawings.

[0007] The invention proposes to implement the lifting operation by means of an eccentric drive. In this way, a simple, inexpensive, robust and low-maintenance solution for lifting and holding large loads can be achieved.

[0008] In order to achieve a particularly compact construction of the transport vehicle and to facilitate maintenance, the transport vehicle has a flat chassis with drive components arranged therein and has at least one load-bearing element which is height-adjustable relative to the chassis and serves to carry the payload. In this case, the eccentric drive has at least one rotatably mounted eccentric element which introduces the lifting force into the load-bearing element during the lifting operation. In this way, by means of the configuration of the eccentric element, the lifting stroke can be defined structurally easily and efficiently, the operating reliability is increased and faults and failures are avoided.

[0009] According to a preferred improvement of the present invention, in order to achieve reliable lifting synchronization, the lifting device comprises a lifting shaft, which extends substantially through the entire chassis in the transverse direction and has an eccentric element at each of the opposite ends. Therefore, the lifting operation can be further easily and inexpensively implemented by a single drive unit acting on the lifting shaft.

[0010] According to a preferred embodiment, the lifting axis is actuated by means of a wraparound drive in order to transmit the forces from the drive unit to the lifting axis robustly while being particularly flexible and making efficient use of the installation space.

[0011] For efficient guidance and support of a load-bearing element that can be implemented inexpensively, at least one edge section of a hole is provided in the load-bearing element, which hole is configured for the lifting shaft to extend therethrough, for guiding the load-bearing element in the lifting direction and for support transversely to the lifting direction.

[0012] According to another development of the invention, in order to further improve the guidance and support of the load-bearing element, the load-bearing element has a flat surface section at the end side, which is formed parallel to the lifting direction, bears in the longitudinal direction on a corresponding area of ​​the chassis and slides on the chassis.

[0013] According to a preferred embodiment, in order to achieve a stable and at the same time weight-saving construction, the transport vehicle has two load-carrying elements which are arranged opposite each other on both sides of the chassis.

[0014] In order to increase the rigidity or to enhance the range of functions, the two load-bearing elements can be connected to one another by means of at least one transverse connection.

[0015] In order to easily implement a robust synchronization of the lifting device in the longitudinal direction, a preferred embodiment of the invention provides that the lifting device has at least two eccentric elements which act on the same load-bearing element and are coupled to one another via a surround drive.

[0016] According to a particularly preferred embodiment of the invention, the eccentric element has a rolling bearing element which is arranged radially on the outside and which rolls on the load-bearing element during the lifting operation. As a result, the eccentric element and its bearing seat do not need to be hardened in order to reduce wear. Likewise, maintenance-intensive lubricants or sliding coatings that are susceptible to contamination or wear can be omitted. In addition, the drive motor does not need to overcome any large friction resistance between the eccentric element and its bearing seat, in addition to the load. The power of the drive unit can be reduced in favor of a smaller construction space and lower energy consumption, or larger loads can be lifted and transported.

[0017] According to a preferred embodiment, the lifting device can include four eccentric elements which are coupled to each other, can be forced to move simultaneously and are used to lift and lower the load. Thus, an uninterrupted and uniform lifting and lowering of the load can be achieved purely mechanically without the need for separate control technology expenditures. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be discussed in more detail below based on exemplary embodiments. In the accompanying drawings:

[0019] Figure 1 is a highly simplified representation of a transport vehicle in plan view (view a) and in side view with the lifting device retracted (b) and deployed (c);

[0020] Figure 2 Shown according to Figure 1 's view, yet with a payload carrier;

[0021] Figure 3 is an exemplary illustration of an embodiment of a transport vehicle wherein a payload is positioned in a payload carrier;

[0022] Figure 4 are a three-dimensional illustration of some elements of the chassis and the lifting device (a) and an enlarged illustration of the guide in the hole of the load-bearing element (b);

[0023] Figure 5 A partial side view of the transport vehicle 1 and some elements of the lifting device 2 is shown in a raised transport position (a) and in a lowered parking position (b);

[0024] Figure 6 An embodiment of an eccentric element with a rolling bearing element is shown;

[0025] Figure 7 A detailed view of the drive of the lifting axis is shown. DETAILED DESCRIPTION

[0026] Figure 1

[0027] The driverless transport vehicle 1 is used in particular for transporting payloads on smooth surfaces in production and assembly plants, for example for transporting parts and components from or to a production line or in a parts warehouse. The transport vehicle 1 autonomously selects its travel route based on integrated spatial monitoring sensors and a control system (which is not emphasized and not shown here, however).

[0028] The transport vehicle 1 has a flat, compact chassis 8, in which and on which all control and drive components are arranged. In the illustrated embodiment, the transport vehicle 1 moves on a pair of support wheels 15 and a pair of drive wheels 14. The drive wheels 14 can be driven individually and independently of each other and are therefore used both for propulsion and for steering of the transport vehicle 1. In order to carry or place a load, the transport vehicle 1 has two load-bearing elements 9, 9', which form an integral part of the lifting device 2. The load-bearing elements 9, 9' have an elongated shape in the longitudinal direction or parallel to the travel direction F and are located laterally on both sides of the chassis 8 in the upper region. In the illustrated embodiment, each load-bearing element 9, 9' is configured as a box-shaped hollow body. In order to lift a load, the load-bearing element 9, 9' can be lifted from the retracted parking position (view b) in the vertical lifting direction H by a lifting stroke 16 into the unfolded transport position.

[0029] The load-bearing elements 9, 9' can be cross-connected (21) by one or more struts, bars or plates (not shown here), for example in order to increase rigidity and / or to achieve a larger flat loading surface.

[0030] Figure 2

[0031] The transport vehicle 1 is designed to preferentially transport payloads in separate payload carriers 6. The payload carriers 6 can be constructed in various forms: in the form of a rack as shown, in the form of a trolley or roller trolley, etc.

[0032] The payload carrier 6 is designed so that the transport vehicle 1 can be driven under the payload carrier 6 with the load-bearing elements 9, 9' in the parked position. The payload carrier 6 has two crossbeams 7, 7' which extend transversely to the direction of travel and on which the load-bearing elements are supported during the lifting and transportation of the payload carrier 6. In the embodiment shown, the crossbeams 7, 7' are connected by two longitudinal members 17, 17' located on the outside. To transport the load, the transport vehicle 1 drives under the payload carrier 6 and activates the lifting device 2. Here, the load-bearing elements 9, 9' are lifted in the lifting direction H, rest on the crossbeams 7, 7' and lift the payload carrier 6 from the ground. The payload carrier 6 can then be transported to the destination and there placed back on the ground in the reverse order.

[0033] Figure 3

[0034] The figure shows an exemplary usage scenario of the transport vehicle 1 and is roughly similar to Figure 2 The situation shown in b corresponds to the situation shown in b. The embodiment of the transport vehicle 1 is located below a payload carrier 6 configured as a roller trolley. The payload carrier 6 is loaded with a payload 22, which consists of a metal mesh box filled with bags.

[0035] Figure 4

[0036] Figure 4 Some structural elements of a chassis 8 with components of the lifting device 2 are shown.

[0037] The lifting device 2 has a lifting shaft 10 which can rotate about an axis of rotation D, extends in the transverse direction substantially through the entire chassis 8 and, when extended, engages with its two ends in two opposite load-bearing elements 9, 9'. In each case, one disk-shaped eccentric element 3, 3" is arranged to be fixed in a rotationally coupled manner at both ends of the lifting shaft 10. Overall, the lifting device 2 has four disk-shaped eccentric elements 3, 3', 3", 3'" which support the load-bearing elements 9, 9' in the vertical direction.

[0038] Each load-bearing element 9, 9' has a hole 11 for the lifting shaft to engage through it. Each hole has an elongated shape in the vertical direction and has two straight edge portions 12 oriented parallel to the lifting direction H and parallel to each other. By means of the two edge portions 12, forces acting in particular parallel to the travel direction F or transversely to the lifting direction H are introduced from the load-bearing element 9 into the lifting shaft 10 and thus into the chassis 8. In this way, the edge portions 12 serve to guide and support the forces for the load-bearing elements 9, 9'.

[0039] Furthermore, each load-bearing element 9 , 9 ′ has at the end side a flat surface portion 13 , 13 ′ formed parallel to the lifting direction H. These surface portions 13 , 13 ′ also serve as vertical guides during the lifting operation and for supporting and introducing longitudinal forces into the chassis 8 .

[0040] Figure 5

[0041] Figure 5 A partial side view of a transport vehicle 1 and some elements of a lifting device 2 (the side walls of the load-bearing element 9 have been removed) is shown in a raised transport position (view a) and in a lowered parking position (view b).

[0042] On each side of the transport vehicle 1, the lifting device (2) has two eccentric elements (3, 3') of equal size, acting on the same load-bearing element (9). Here, the eccentric element 3 on the drive side of the lifting shaft 10 is coupled to the other eccentric element 3' on the output side by means of a wraparound drive 18, so that when the lifting shaft 10 rotates, the two eccentric elements 3, 3' rotate simultaneously in the same direction. In the above-described embodiment, the wraparound drive 18 is embodied as a chain drive. However, other embodiments (for example in the form of a toothed belt drive) are also possible within the invention.

[0043] In order to perform the lifting movement, the rotational movement of the lifting shaft 10 is converted into a translational movement of the load-bearing element 9 parallel to the lifting direction H by the eccentric elements 3, 3'. The upper horizontal rail of the load-bearing element 9 serves here as a bearing seat for the eccentric elements 3, 3'. In order to reduce the friction between the eccentric elements 3, 3' and the load-bearing element 9, each eccentric element 3, 3' is equipped with a rolling bearing element 4 on the radial outside, by means of which the eccentric element rolls quietly and with low friction on its bearing seat. By means of the edge section 12 (as already mentioned above) and the surface section 13 of the hole 11, a force component directed transversely to the lifting direction H is introduced into the chassis 8 when the eccentric element 3, 3' rolls on the load-bearing element 9.

[0044] Figure 6

[0045] Figure 6 An embodiment of an eccentric element 3 is shown. The rolling bearing element 4 is located at the radial outer edge of the eccentric disc 24. In the embodiment shown, the rolling bearing element 4 is configured as a ball bearing pressed onto the eccentric disc 24. However, in the present invention, it is also conceivable that the eccentric disc 24 itself is configured as a component of the rolling bearing, for example an inner ring.

[0046] The lifting stroke 16 of the lifting device 2 is structurally defined as twice the radial distance between the center point M of the eccentric disk 24 and the rotation axis D of the center of the lifting shaft seat 23 .

[0047] Figure 7

[0048] Figure 7 A preferred embodiment is shown in which the lifting axis 10 is actuated by means of a wraparound drive 19 which is activated by an electric drive unit 20. The drive unit 20 thus serves as a lifting drive for the lifting device 2.

[0049] In the preferred embodiment shown, the circumferential drive 19 is configured as a chain drive. However, in the present invention, the drive can be in other configurations, such as a belt drive, as required.

[0050] Reference numerals list

[0051] 1 Transport vehicles

[0052] 2 Lifting equipment

[0053] 3 Eccentric element

[0054] 4 Rolling bearing elements

[0055] 5 Support seat

[0056] 6 Payload Carrier

[0057] 7 Beam

[0058] 8 Chassis

[0059] 9 Load carrying elements

[0060] 10 Lifting axis

[0061] 11 holes

[0062] 12 Edge

[0063] 13 Surface part

[0064] 14 Drive wheel

[0065] 15 Support wheel

[0066] 16 Lifting stroke

[0067] 17 Longitudinal member

[0068] 18 Wraparound Driver

[0069] 19 Wraparound Driver

[0070] 20 Drivers

[0071] 21 Transverse connector

[0072] 22 Payload

[0073] 23 Lifting shaft seat

[0074] 24 Eccentric disc

[0075] M Center point

[0076] D Rotation axis

[0077] F Driving direction

[0078] H Lifting direction

Claims

1. An unmanned transport vehicle (1) for transporting a load, the transport vehicle having a lifting device (2) configured to lift the load so that the load can be transported in a lifted state, characterized in that Lifting operation is performed by means of an eccentric drive; The transport vehicle (1) has a chassis (8) with drive components arranged therein, the lifting device (2) comprises at least one load-bearing element (9) which is height-adjustable relative to the chassis (8) and is used to carry the load, the eccentric drive having at least one rotatably mounted eccentric element (3) which introduces a lifting force into the load-bearing element (9) during the lifting operation; The lifting device (2) comprises a lifting shaft (10) which extends substantially through the entire chassis (8) in a transverse direction and has an eccentric element (3, 3") at each of the opposite ends; The load-bearing element (9) has at least one hole (11) through which the lifting shaft (10) extends, wherein at least one edge portion (12) of the hole (11) is configured to guide the load-bearing element (9) in a lifting direction (H) and to be supported on the lifting shaft (10) transversely to the lifting direction (H).

2. The transport vehicle (1) according to claim 1, characterized in that The lifting shaft (10) is actuated via a surround drive (19).

3. The transport vehicle (1) according to claim 1 or 2, characterized in that: The load-bearing element (9) has a flat surface section (13) on its end side, which is formed parallel to the lifting direction (H) and is provided for supporting and introducing forces into the chassis (8) in the longitudinal direction.

4. The transport vehicle (1) according to claim 1 or 2, characterized in that: The transport vehicle (1) has two load-bearing elements (9, 9') which are arranged opposite each other on both sides of a chassis (8).

5. The transport vehicle (1) according to claim 4, characterized in that The two load-bearing elements (9, 9') are connected to each other by at least one transverse connection (21).

6. The transport vehicle (1) according to any one of claims 1, 2 and 5, characterized in that The lifting device (2) has at least two eccentric elements (3, 3') which act on the same load-bearing element (9) and are coupled to one another via a revolving drive (18).

7. The transport vehicle (1) according to any one of claims 1, 2 and 5, characterized in that The eccentric element (3) has a rolling bearing element (4) which is arranged radially on the outside and which rolls on the load-bearing element (9) during the lifting operation.

8. The transport vehicle (1) according to any one of claims 1, 2 and 5, characterized in that The lifting device (2) comprises four eccentric elements (3, 3', 3", 3'") which are coupled to one another, can be forced to move simultaneously and are used to lift and lower the load.

9. The transport vehicle (1) according to any one of claims 1, 2 and 5, characterized in that The transport vehicle (1) is an automatically guided transport vehicle.

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