DRIVERLESS TRANSPORT VEHICLE WITH A PAYLOAD LIFTING DEVICE.

Description

[0001] The invention relates to a driverless, in particular automatically guided, and preferably autonomously guided transport vehicle for transporting payloads. Such vehicles are usually used as so-called industrial trucks or material transport vehicles in production plants, for example, to transport specific payloads within the warehouse or from the warehouse to the production line, preferably navigating autonomously. The load in such transport vehicles can consist either directly of the payload itself or of a payload carrier, which can be separately loaded with the payload – for example, a frame, a rolling base, and the like. The transport vehicle is intended to be able to drive under such a payload carrier, lift it independently, transport it to the destination, and set it down again there. For this purpose, it is equipped with an integrated lifting device.

[0002] Various solutions for implementing the lifting function are known from practice. To lift large loads quickly and precisely, the lifting device requires high rigidity and powerful motors, with a correspondingly high electrical energy requirement. This results in higher weights, larger batteries, higher costs, or reduced ranges.

[0003] From DE 102013013438 A1, for example, a transport vehicle is known whose lifting function is realized via various pushing and lever devices, which, due to the design principle and rigidity requirements, have a high system weight and a large installation space requirement.

[0004] From EP 102706 A1, another transport vehicle is known whose lifting device is constructed with ball screws that are complex to manufacture and comparatively expensive.

[0005] WO 2014 / 118716 A2 discloses the preamble of claim 1.

[0006] Reference is also made to CN 110 482 442 A.

[0007] Against this background, the object of the invention is to propose a transport vehicle with a lifting device which can be constructed as cost-effectively as possible and at the same time as rigidly and efficiently.

[0008] This object is achieved by the combination of features according to the independent claim. Further embodiments and developments of the invention emerge from the subclaims as well as the following description and figures.

[0009] The invention provides for the lifting process to be implemented via an eccentric drive. This enables a simple, cost-effective, robust, and low-maintenance solution for lifting and holding large loads.

[0010] To achieve a particularly compact and low-maintenance design for the transport vehicle, it features a flat chassis with drive components arranged therein, as well as at least one load-bearing element that is height-adjustable relative to the chassis for carrying the payload. The eccentric drive comprises at least one rotatably mounted eccentric element, which transmits a lifting force to the load-bearing element during the lifting process. This allows the stroke to be determined simply and effectively by designing the eccentric element, increasing operational reliability and preventing malfunctions and failures.

[0011] For reliable stroke synchronization, the lifting device according to the invention comprises a lifting shaft that extends transversely essentially through the entire chassis and has an eccentric element at each of the opposite ends. Furthermore, the lifting process can be implemented simply and cost-effectively with a single drive unit acting on the lifting shaft.

[0012] In order to ensure robust power transmission from the drive unit to the lifting shaft while simultaneously ensuring particularly flexible and effective use of installation space, the lifting shaft is actuated by a belt drive according to a preferred embodiment.

[0013] For cost-effective, efficient guidance and support of the load carrier element, the invention provides that at least one edge section of an opening in the load carrier element designed for the passage of the lifting shaft is provided for guiding the load regulator in the lifting direction and supporting it transversely to the lifting direction.

[0014] For further improved guidance and support of the load carrier element, according to a further development of the invention, the latter has a flat surface section on the front side which is formed parallel to the lifting direction and which rests and slides longitudinally on a corresponding area of ​​the chassis.

[0015] According to a preferred embodiment, the transport vehicle has two load-carrying elements for a stable and at the same time weight-saving structure, which are arranged opposite one another on both sides of the chassis.

[0016] To increase rigidity or expand the range of functions, the two load-bearing elements can be connected to each other via at least one cross connection.

[0017] For an easy-to-implement 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 carrier element and are coupled to one another via a belt drive.

[0018] According to a particularly preferred embodiment of the invention, the eccentric element has a roller bearing element arranged radially on the outside and rolling against the load-bearing element during the lifting process. The eccentric element and its counterbearing therefore do not need to be hardened to reduce wear. Likewise, maintenance-intensive and contamination-prone lubricants or wear-prone sliding coatings are eliminated. Furthermore, the drive motor does not have to overcome significant frictional resistance between the eccentric element and its counterbearing in addition to the load. The power of the drive unit can be reduced to reduce installation space and energy consumption, or larger loads can be lifted and transported.

[0019] According to a preferred embodiment, the lifting device can comprise four interconnected and simultaneously movable eccentric elements, which serve to raise and lower the load. This allows for trouble-free and uniform raising and lowering of the load, purely mechanically and without the need for additional control.

[0020] The present invention is explained in more detail below using an exemplary embodiment. In the following: Fig.1 Highly simplified representation of the transport vehicle in top view (view a) and side views with retracted (b) and extended (c) lifting device. Fig.2 Views according to Fig.1 , but additionally with a payload carrier. Fig.3 exemplary representation of an embodiment of the transport vehicle with a payload in a payload carrier. Fig.4 spatial representation of some elements of the chassis and the lifting device (a) and an enlarged representation of the guide in the opening of the load carrier element (b). Fig.5 Side view of some elements of the transport vehicle 1 and the lifting device 2 in the raised transport position (a) and in the lowered parking position (b). Fig.6 an embodiment of an eccentric element with a rolling bearing element. Fig.7 Detailed view of the lifting shaft drive. Fig. 1

[0021] The driverless transport vehicle 1 is used primarily for transporting payloads on smooth floors in production and assembly plants, for example, to transport parts and components to and from the production line or parts warehouse. The transport vehicle 1 selects its route autonomously, based on integrated room monitoring sensors and a control system, which, however, are not highlighted or illustrated here.

[0022] The transport vehicle 1 has a flat, compact chassis 8, in and on which all control and drive components are arranged. In the embodiment shown, the transport vehicle 1 moves on a pair of support wheels 15 and a pair of drive wheels 14. The drive wheels 14 are independent of each other, can be driven individually, and thus serve both for propulsion and steering of the transport vehicle 1.

[0023] To carry or place the load, the transport vehicle 1 has two load-carrying elements 9, 9', which form part of a lifting device 2. The load-carrying elements 9, 9' are designed to be elongated longitudinally or parallel to the direction of travel F and flank the chassis 8 laterally in the upper area. In the embodiment shown, each load-carrying element 9, 9' is designed as a box-shaped hollow body. To lift the load, the load-carrying elements 9, 9' can be raised in the vertical lifting direction H from a retracted parking position (view b) by a lifting amount 16 into an extended transport position.

[0024] Load carrier elements 9, 9' can be cross-connected (21) via one or more struts, bands or plates not shown here, for example to increase rigidity and / or to create a larger, flat loading area. Fig.2

[0025] The transport vehicle 1 is designed for the preferential transport of payloads in a separate payload carrier 6. The payload carrier 6 can be constructed in various ways—as a frame as shown, as a trolley or rolling base, and the like.

[0026] The payload carrier 6 is constructed such that the transport vehicle 1 with load carrier elements 9, 9' can drive under the payload carrier 6 in the parking position. The payload carrier 6 has two cross members 7, 7' running transversely to the direction of travel, on which the load carrier elements are supported when lifting and transporting the payload carrier 6. In the embodiment shown, the cross members 7, 7' are connected via two external longitudinal members 17, 17'. To transport the load, the transport vehicle 1 drives under the payload carrier 6 and activates the lifting device 2. The load carrier elements 9, 9' are lifted in the lifting direction H, rest against the cross members 7, 7' and lift the payload carrier 6 from the ground. The payload carrier 6 can then be transported to the destination and placed back on the ground in the reverse order. Fig.3

[0027] The figure shows an example of a usage scenario of the transport vehicle 1 and essentially corresponds to the one in the Fig.2b The situation shown is shown in Figure 1. One embodiment of the transport vehicle 1 is located under a payload carrier 6, which is designed as a rolling base. The payload carrier 6 is loaded with a payload 22, which consists of a lattice box filled with bags. Fig.4

[0028] Fig. 4 shows some structural elements of the chassis 8 with components of the lifting device 2.

[0029] The lifting device 2 has a lifting shaft 10 rotatable about the rotation axis D, which essentially extends transversely through the entire chassis 8 and engages with its ends in the two opposite load-bearing elements 9, 9'. A disc-shaped eccentric element 3, 3" is arranged at each end of the lifting shaft 10, fixed in a rotationally fixed manner. In total, the lifting device 2 has four disc-shaped eccentric elements 3, 3', 3", 3‴, which support the load-bearing elements 9, 9' in the vertical direction.

[0030] Each load-bearing element 9, 9' has an opening 11 for the lifting shaft to pass through. This opening is vertically elongated and has two straight edge sections 12, which are aligned parallel to the lifting direction H and to each other. Through these two edge sections 12, forces acting, in particular, parallel to the direction of travel F or transverse to the lifting direction H are transferred from the load-bearing element 9 into the lifting shaft 10 and thus the chassis 8. The edge sections 12 thus serve to guide and support the load-bearing elements 9, 9'.

[0031] Furthermore, each load-bearing element 9, 9' has a flat surface section 13, 13' on its front side, parallel to the lifting direction H. These surface sections 13, 13' also serve as vertical guides during the lifting process, as well as for supporting and transmitting longitudinal forces into the chassis 8. Fig.5

[0032] The Fig. 5 shows a partial side view of some elements of the transport vehicle 1 and the lifting device 2 with a removed side wall of the load carrier element 9 in the raised transport position (view a) and in the lowered parking position (view b).

[0033] On each side of the transport vehicle 1, the lifting device (2) has two equally sized eccentric elements (3, 3'), which act on the same load-bearing element (9). The drive-side eccentric element 3, located on the lifting shaft 10, is coupled to the other, output-side eccentric element 3' via a belt drive 18, so that when the lifting shaft 10 rotates, both eccentric elements 3, 3' rotate simultaneously in the same direction. In the above embodiment, the belt drive 18 is implemented as a chain drive. However, other embodiments, for example, as a toothed belt drive, are also permissible within the scope of the invention.

[0034] To perform a lifting movement, the rotational movement of the lifting shaft 10 is converted by the eccentric elements 3, 3' into a translational movement of the load-bearing element 9 parallel to the lifting direction H. The upper horizontal bar of the load-bearing element 9 serves as a counterbearing for the eccentric elements 3, 3'. To reduce friction between the eccentric elements 3, 3' and the load-bearing element 9, each eccentric element 3, 3' is equipped radially on the outside with a rolling bearing element 4, which it collects at its counterbearing with low noise and low friction. The force components generated when the eccentric elements 3, 3' roll on the load-bearing element 9 and directed transversely to the lifting direction H are introduced into the chassis 8 through the aforementioned fire sections 12 of the opening 11 and the surface section 13. Fig.6

[0035] Fig. 6 shows an embodiment of the eccentric element 3. A rolling bearing element 4 is located on the radial outer edge of an eccentric disc 24. In the embodiment shown, the rolling bearing element 4 is designed as a ball bearing pressed onto the eccentric disc 24. Within the scope of the invention, however, it is equally conceivable to design the eccentric disc 24 itself as a component, for example, the inner ring of a rolling bearing.

[0036] The double radial distance between the center M of the eccentric disc 24 and the axis of rotation D in the center of the lifting shaft holder 23 structurally defines the stroke 16 of the lifting device 2. Fig.7

[0037] Fig. 7 shows a preferred embodiment of the lifting shaft 10 by means of a belt drive 19, which is activated by an electric motor drive unit 20. The drive unit 20 thus functions as the lifting drive of the lifting device 2.

[0038] In the preferred embodiment shown, the belt drive 19 is provided as a chain drive. Within the scope of the invention, depending on the requirements, it can also be designed differently, for example, as a belt drive. List of reference symbols

[0039] 1Transport vehicle 2Lifting device 3Eccentric element 4Rolling bearing element 5Counter bearing 6Payload carrier 7Traverse 8Chassis 9Load carrier element 10Lifting shaft 11Breakthrough 12Edge section 13Surface section 14Drive wheel 15Support wheel 16Lift 17Longitudinal member 18Belt drive 19Belt drive 20Drive unit 21Cross connection 22Payload 23Lifting shaft holder 24Eccentric disc MCenter point DRotation axis FDirection of travel HLifting direction

Claims

1. Driverless, in particular automatically guided transport vehicle (1) for transporting a load, having a lifting apparatus (2) which is configured to lift the load such that said load can be transported in the lifted state, wherein the transport vehicle (1) has a chassis (8) with drive components arranged therein, and the lifting apparatus (2) comprises at least one load-carrier element (9) which is height-adjustable relative to the chassis (8) and which serves for carrying the payload, and wherein the lifting operation is realized via an eccentric drive which has at least one rotatably mounted eccentric element (3) which, during the lifting operation, introduces a lifting force into the load carrier element (9), and wherein the lifting apparatus (2) comprises a lifting shaft (10) which extends in a transverse direction substantially through the entire chassis (8) and which has in each case one eccentric element (3, 3") at opposite ends, wherein the load-carrier element (9) has at least one aperture (11), characterized in that the lifting shaft (10) extends through the aperture, and wherein at least one peripheral portion (12) of the aperture (11) is configured for guidance of the load-carrier element (9) in a lifting direction (H) and for support transversely to the lifting direction (H) on the lifting shaft (10).

2. Transport vehicle (1) according to Claim 1, characterized in that the lifting shaft (10) is actuated via a wraparound drive (19).

3. Transport vehicle (1) according to at least one of the preceding claims, characterized in that the load-carrier element (9) has at an end face a planar surface portion (13) which is formed parallel to the lifting direction (H) and which is intended for support and introduction of force into the chassis (8) in a longitudinal direction.

4. Transport vehicle (1) according to at least one of the preceding claims, characterized in that the transport vehicle (1) has two load-carrier elements (9, 9'), which are arranged in each case oppositely on both sides of the chassis (8).

5. Transport vehicle (1) according to Claim 4, characterized in that the two load-carrier elements (9, 9') are connected to one another via at least one transverse connection (21).

6. Transport vehicle (1) according to at least one of the preceding claims, characterized in that the lifting apparatus (2) has at least two eccentric elements (3, 3') which act on the same load-carrier element (9) and are coupled to one another via a wraparound drive (18).

7. Transport vehicle (1) according to at least one of the preceding claims, characterized in that the eccentric element (3) has a rolling-bearing element (4) which is arranged radially at the outside and which, during the lifting operation, rolls on the load-carrier element (9).

8. Transport vehicle (1) according to at least one of the preceding claims, characterized in that the lifting apparatus (2) comprises four eccentric elements (3, 3', 3", 3"') which are coupled to one another and which are forcibly movable simultaneously and which serve for lifting and lowering the load.