WO2024179954A1

WO2024179954A1 - Method of planning a conveyor arrangement

Info

Publication number: WO2024179954A1
Application number: PCT/EP2024/054744
Authority: WO
Inventors: Christian ÖHM; Christian HAGMAIER; Hubertus MARX; Christian Ripperda
Original assignee: Interroll Holding AG
Current assignee: Interroll Holding AG
Priority date: 2023-02-27
Filing date: 2024-02-26
Publication date: 2024-09-06
Anticipated expiration: 2025-08-27
Also published as: CN120752189A

Abstract

Method of planning a conveyor arrangement (1), the conveyor arrangement is adapted to convey an object (9) from at least one first location (F) to at least one second location (D); wherein during intended use of the operation an operator interacts with said object (9) located within the conveyor arrangement (1) within a human working space (SA); the method comprising the step of providing an IT planning tool (8) for usage by a user; wherein by using the IT planning tool (8), representations (83) of a plurality of conveyor components, in particular conveyor zones (2), are arranged in a manner to form a representation of said conveyor arrangement (1); wherein the IT planning tool (8) is adapted to distinguish the areas (C, D, F) of the conveyor arrangement (1) between non-human working spaces and human working space (SA).

Description

Method of planning a conveyor arrangement

Description

The invention refers to a method of planning conveyor arrangement.

EP 3222 564 B1 discloses a conveyor for conveying an object from a start position to a target place. The conveyor comprises a plurality of zones into which the conveyor is divided, the object being conveyed across the zones; each of the zones comprising: a linear conveyor zone that linearly conveys the object; a conveying direction changing zone selecting a conveying direction of the object to send out the object in the selected conveying direction; a conveyance destination storage unit that is configured to store the conveyance destination information temporarily; an information receiving unit that is configured to receive the conveyance destination information from an upstream zone; and an information transmitting unit that is configured to transmit the conveyance destination information to a downstream zone. The conveyor transfers the conveyance destination information from the upstream zone to the downstream zone with the movement of the object across the zones.

WO 2021/048042 A1 , also published as EP 3 792 206 A1 , discloses a virtual layouter tool. Here a conveyor arrangement can be created in the virtual world using 3D data of individual conveyor modules. The 3D data of the conveyor devices are arranged in a spatial relation to each other which conforms a possible relation of the relating real module devices in the real world. The created conveyor arrangement in the virtual world can be used in a simulation mode for predicting an efficient use and configuring a sufficient capacity of the conveyor arrangement.

In the virtual layouter tool presented in WO 2021/048042 A1 / EP 3 792 206 A1 a tool machine is surrounded by a fence, which has the purpose, to keep people away from the machine. Separate to the fence, a plurality of human working spaces are visible, where a human is in immediate contact to the objects conveyed with the conveyor arrangement. Any human interactions related to the conveyed objects, e.g. loading or unloading of objects on the conveyor happen outside of the zone guarded by the fence. The fence does not provide any safety in relation to the interaction of humans with objects located on the conveyor.

WO 2018/191122 A1 refers to the field of transfer guards providing a smooth transition to support objects traveling across a gap between two conveyor surfaces, such as two pulleys of separate belts, and to prevent objects from falling into the gap. Any topics related to a user interaction during normal operation are not part of the disclosure.

US 2022/009722 A1 discloses a roller having a drive unit, which is arranged with a roller body and adapted to generate a torque between an axle element and the roller body. A sensor function unit is arranged within the roller body and which is designed to detect a conveyed material for conveying by means of the motor-operated conveying roller. A control unit is connected to the sensor function unit, wherein the control unit is designed to receive a sensor signal from the sensor function unit and to transmit a control signal to the drive unit n a manner dependent on the sensor signal, wherein the control signal comprises data for the drive of the motor operated conveying roller with a characteristic profile which is predetermined by the control signal, in a conveying operating mode. It is an object of the invention to improve the safety for humans handling objects located on the conveyor in a human working space. The invention comprises a method and a conveyor arrangement according to the main claims; embodiments are subject of the subclaims and the description.

The conveyor arrangement to be planned with the help of the inventive method is adapted to convey an object from at least one first location to at least one second location. A first location may be a feed in station; a second location may be a destination. An user may get in interaction with the object to be conveyed.

The inventive method comprises the step of providing an IT planning tool for usage by an user; wherein by using the IT planning tool, representations of a plurality of conveyor components, in particular conveyor zones, are arranged in a manner to form a representation of said conveyor arrangement; the IT planning tool is adapted to distinguish the areas of the conveyor arrangement between non-human working spaces and human working spaces.

Thereby that the IT planning tool may be adapted to add a human working space definition and/or withdraw said human working space definition to I from a conveyor area.

The method enables to automate several steps during planning, which are dependent on the later usage. In particular it is intended during later usage, that in the human working space an operator gets in interaction with the objects within the human working space . Due to this interaction there is an increased risk for the operator to get also in contact with moving components of the conveyor. Due to the definition the IT planning tool can support the user in planning a safe conveyor arrangement.

In an embodiment, based on an input, in particular an user interaction, the IT planning tool adds or withdraws said human working space definition to I from said conveyor area. The term “user interaction” is to be understood broadly. Alternative to an user interaction, the IT planning tool can derive the fact from any other suitable information. E.g. if certain components may be inherent to interact with an operator, such as a terminal chute or a manual picking location. Here it is not required, that the user provides an explicit interaction, so that the pure provision of such a component is considered as the triggering input. Within the present application it is to be distinguished between the user and the operator. The user is a person who is handling the IT tool during planning. The operator is a person which gets in interaction with the objects to be conveyed during the intended usage of the planned conveyor arrangement.

The claimed conveyor arrangement comprises a motorized roller with can be operated based on a setpoint values limiting the maximum drive torque provided by the motorized roller. By limiting the maximum torque, the risk of injuries can be reduced, since crushing forces are reduced.

The setpoint values limiting the maximum torque is provided to the motorized roller from outside of the motorized roller, so that the motorized roller can be switched between different modes of operation. The modes of operation differs from each other in the amount of the set point value or in the fact that one mode of operation does not consider such a torque limitation at all.

Unless stated otherwise, the terms upstream and downstream refer to the direction of travel.

An example embodiment of the invention is described in more detail with the help of the figures; herein show fig. 1 a conventional conveyor zone in perspective view; fig. 2 a conventional basic conveyor arrangement; fig. 3 schematic representations of different conveyor zones; fig. 4 principal sketch of a conveyor arrangement; fig. 5 a personal computer on which the IT planning tool is running in an initial planning step; fig. 6 -11 the personal computer of fig. 5 in subsequent planning steps; fig. 12 a longitudinal section through motorized conveyor roller according to the invention.

Figure 1 shows an exemplary conveyor zone 2, comprising several conveyor rollers 3 mounted on a common support frame 4. The conveyor rollers 3s are driven together by a common motor. For this purpose, one of the conveyor rollers 3 is designed as a motorized conveyor roller 3M. The motorized conveyor roller 3M is driven in particular by a three-phase motor arranged within the conveyor roller. Via one or more drive connectors 31 , e.g. a drive belt, the conveyor rollers 3 of a conveyor zone 2 are drive-connected to each other and are jointly driven by the motorized conveyor roller 3M. An upper side of the rollers form a conveyor surface Sc, on which an object 9 is in particular linearly conveyed from an inlet I to an outlet O along a conveying direction d.

In another embodiment a conveyor belt is used instead of rollers; accordingly the conveyor surface Sc is formed by an upper side of the conveyor belt (not shown in figure 1 and 2).

By means of a presence sensor 5, the presence of a conveyed object 9 arranged on the conveyor zone 2 can be determined as soon as the object comes into the field of view of the sensor 5.

The motorized conveyor rollers 3M are each controlled by at least one or a plurality of zone controllers 11 (figure 2). A local zone controller 11 can control the motorized conveyor rollers 3M of several conveyor zones 2. A plurality of zone controllers 11 are arranged in a conveyor arrangement 1 , which communicate with each other via a bus connection 13.

Figure 2 shows a basic conveyor arrangement 1 , where conveyor zones 2a..e as described previously are used. A plurality of zone controllers 11 control the operation of the conveyor zones 2. A PLC 12 (programmable logic control) may be provided to control the overall operation of the conveyor arrangement 1.

Scanners (not shown) may be arranged along the zones and provide identification data relating to objects 9a..c passing the scanner in the zones. These identification data are sent via bus connection 13 to the PLC 12. The PLC 12 has access to an object data base (not shown), which provides destination data based in the identification of the objects 9. Based on the acquired data the PLC 12 provides operation instruction to a local zone controller 11, how to handle the object 9, i.e. to which of the outlets O said object 9 is to be conveyed.

In an alternative embodiment as described in the WO 2023/247237 A1 , no PLC or similar is required. Instead of a PLC the zone controllers are connected to a common higher-level object data broker, in particular via the bus connection, with which the zone controllers are also connected to one another. The data broker provides destination data related to the identified objects and the zone controllers are adapted to control operation of the zones based on the provided destination data.

In particular the zone controllers 11 control the motorized conveyor rollers 3M in such a way that the successively approaching conveyed objects 9 do not collide with each other, which is usually called “zero pressure accumulation”. The control takes place in such a way that essentially only one conveyed object 9 is present per conveyor zone 2. However, slight overlaps may occur. For example, an upstream object 9b located on an upstream conveyor zone 2c may already enter a downstream conveyor zone 2d even though the downstream object 9a has not yet left this downstream conveyor zone 2d completely. Among other things, the sensor signals of the presence sensors 5 serve as input variables here, although it is ensured that the two conveyed objects 9 do not touch and thus do not damage each other.

In the following course of the invention, reference is made to conveyor zones 2, using a schematic representation of said conveyor zone 2 as shown in figure 3. Here figure 3a represents schematically a conveyor zone 2 of figure 1 , which has one first inlet 11 and one first outlet 01. No more inlets and outlets are provided. The conveyor zone 2 can also be curved or from other shape.

Figure 3b shows the representation of another conveyor zone 2 having an extended scope of operation. Here in addition to the conveyor zone 2 of figure 3a the conveyor zone 2 has an additional, second outlet 02. The object 9 can be conveyed selectively from said first inlet 11 to one of said first and second outlets 01, 02. Optionally, the conveyor zone 2 has an additional, third outlet 03. In this option, the object 9 can be conveyed selectively from said first inlet 11 to one of said first, second and third outlets 01 , 02, 03.

As an example, said conveyor zone 2 of figure 3b can be formed by a conveyor zone 2 as shown in figure 1 , which additionally is provided with a transfer device as described with reference to figure 5 of EP 3222 564 B1 (in this document and figure the transfer device has reference sign 20).

Figure 3c shows the representation of a conveyor zone 2 having an extended scope of operation. Here in addition to the conveyor zone 2 of figure 3a, the conveyor zone 2 has an additional second inlet I2. Objects 9 can be conveyed from one of said first and second inlets 11 , I2 to said first outlet 01.

The transfer device as described with reference to figure 3b may also be suitable to provide said additional second inlet I2.

Figure 3d shows the representation of a conveyor zone 2 having an extended scope of operation. Here in addition to the conveyor zone 2 of figure 1 the conveyor zone 2 has an additional second inlet I2 and an additional second outlet 02 and is an example as a combination of the embodiments of figures 3b and 3c.

All conveyor zones 2 are controlled by a zone controller 11 as shown in figure 1 or 2, in particular wherein one zone controller 11 may be adapted to control the operation of more than one zone 2. Starting from figure 4 the planning of a conveyor arrangement 1, which is performed by a person, herein called the planner.

Figure 4 shows a principal sketch of what the conveyor arrangement 1 should finally look like.

The conveyor arrangement 1 according to the sketch has two feed in stations F, where a user can input objects 9 to be conveyed. From the feed in stations F the objects 9 are conveyed to several destinations D by several conveyors C. A plurality of junctions J are provided, at which the objects 9 are selectively transferred onto one of a plurality of routes along the conveyors C. Such a sketch may be only available in the head of a planner.

Reference is now made to figure 5. For detailed planning the planner uses an IT tool 8, which is an application program running on a personal computer 7, where the term personal computer also includes tablet PC or similar devices. The IT planning tool 8 is herein also called the “layouter”.

The layouter 8 provides a construction area 81 in which the planner can create a digital representation of a conveyor arrangement 1. The layouter 8 provides a selection area 82, in which components are provided for being selected by the planner. By a user interaction III the user can select a graphical representation 83 of a certain component and transfer the selected component via drag & drop into the construction area 81.

After a few repetitions a small conveyor arrangement 1 has been created already in the construction area 81 , comprising a straight line of roller conveyors C.

Figure 6 shows in the construction area 81 the representation of the further developed conveyor arrangement 1. In addition to the situation in figure 5, the conveyor arrangement 1 comprises now the junctions J as well as a number of merges M branching off at the junctions J.

Figure 7 shows in the construction area 81 the representation of the further developed conveyor arrangement 1. In addition to the situation in figure 6, the conveyor arrangement 1 comprises now additional conveyors C downstream of the merges M. Also the feed in stations F and the connecting conveyors C are provided, which are connected via a junction J to the previous conveyors C.

Figure 8 shows in the construction area 81 the representation of the further developed conveyor arrangement 1. In addition to the situation in figure 7, the conveyor arrangement 1 comprises the destinations D branching off from the conveyors C downstream of the merges M. Additional junctions J are provided where the destinations D branching off from previous conveyors C. Here the destination D are in the form of roller conveyor.

As can be realized by a comparison between the figure 8 and 7 the focus of the construction area can be varied by the planner.

The junction J can be realized by various embodiments. As a usual embodiment a junction J can be established by a roller conveyor which is equipped with a transfer device such as shown e.g. in figure 5 of EP 3222 564 B1.

Figures 9 und 10 show within the construction area 81 a representation of a destination D. The destination D is an exemplary area, where an operator person is in immediate interaction with the objects 9 located on the rollers 3. In particular the operator takes an object 9 with his hands and moves it away from the conveyor C. Due to the direct interaction with the objects 9 located on the conveyor, there is an increased likelihood, that the user gets in contact with the rollers 3. As a consequence a user’s finger f may get into the gap G between two rollers 3 or can get in contact with the Poly-V belts 31. The destination is therefore an example of a human working space, where a user interacts with his hands with the objects located on the conveyor. Another exemplary interaction is, that a human puts an object on the conveyor or that a user modifies an object located on the conveyor (e.g. adds device to the object or remove a device from the object, puts a label on the object etc.).

The layouter 8 provides now a possibility to define any area of the conveyor arrangement 1 (in particular parts of a conveyor zone 2 or the complete conveyor zone 2) as a human working space I safety area SA. In the present example the destination D constitutes said conveyor area, which should be defined as a human working space SA. In the same manner the feed in station F (figure 7) and/or any other conveyor C may constitute a conveyor area which is to be defined as a human working space I safety area SA.

For defining said human working space I SA the layouter 81 provides a human working space definition box 84.

In figure 9 the human working space definition box 84 is unselected; in figure 10 the human working space definition box 84 is selected by a user interaction III.

Through amending the selection status between “unselected” and “selected” by the user interaction III the definition as a human working space SA can be added to a conveyor area or withdrawn from the conveyor area. It should be noted, that there are several other possibilities to define the human working space status. As a consequence of defining the conveyor area as a human working space SA, in an embodiment the layouter 8 automatically performs design changes by providing said conveyor area with safety features 61, 62, 63.

A first exemplary safety feature is a filler plate 61. The filler plate 61 is adapted to reduce a gap G (figure 9) between two adjacent conveyor rollers 3 to a smaller gap g (figure 9) between the conveyor roller 3 and the filler plate 61. The larger gap G (figure 9) between the rollers is in particular larger than 5mm. The remaining smaller gap g (figure 10) is dimensioned so small so that no finger can be inserted through it. In particular the smaller gap does not exceed a width of 5mm.

There is also a plurality of other safety features possible. As a second example, a second safety feature in the form of a closed side guide 62 (figure 10) is provided, hindering any finger to be inserted underneath the conventional side guide (figure 9) (for details and advantages of the closed side guide see also applicants former patent application PCT/EP2024/051888).

The first and second safety features are mechanical safety devices.

A third exemplary safety feature is an operational parameter, in the present example a “drive torque limitation” 63. This safety feature limits the torque of a conveyor drive within the human working space SA to a safety maximum torque Tmax (threshold value, also called safety maximum). This third safety feature can be realized in two different ways.

In a first way, a fixed operational parameter is used. Here a motorized roller 3M is selected, which has a construction based limitation not enabling to generate torque above the safety maximum Tmax.

In a second way, a variable operational parameter is used. Here the motorized roller 3M is constructed in such a manner to allow the generation of torque above the safety maximum Tmax; however the motorized roller 3M is controlled in a way, so that during operation the generated torque does actually not exceed the safety maximum Tmax.

The reduced torque lowers the risk of injuries caused by crushing an operator’s hand between the object 9 and another item, e.g. another object 9.

In an embodiment (see figure 10) the layouter 8 may perform a design change by introducing the at least one safety feature 61, 62, 63 automatically into the representation of the conveyor arrangement 1 within the construction area 81 , in case the conveyor area is defined as a human working space SA. In an embodiment (see figure 11) the layouter 8 may propose a design change by providing a safety feature selection box 85, in which at least one safety feature is provided for selection and I or unselection. Based on the choice of the user, the layouter 8 introduces the at least one safety feature 61, 62 into the representation of the conveyor arrangement 1 (partly shown) within the construction area 81.

As soon as the user unselects a safety feature (here as an example the filler plate 61), said unselected feature disappears from the representation of the conveyor in the construction area 81.

In the safety feature selection box 85 a third safety feature 63 is included, called “drive torque limitation”. By selecting this safety feature 63, the torque of a conveyor drive within the human working space SA is reduced to a safety maximum Tmax. The reduced torque lowers the risk of injuries caused by crushing an operator’s hand between the object 9 and another item, e.g. another object 9.

Figure 12 shows a schematical partial longitudinal half section of the motorized roller 3 of the conveyor zone of figure 1. The roller 3 has a cylindrical roller tube 39. At the axial ends of the roller tube 39 endcaps 32 are attached. The endcaps 32 house bearings 33 which are supported on a shaft 34. The roller shaft 34 may comprise two separate stub shafts, each located at an axial end of the roller tube 39.

The motorized roller 3M may comprise an attachment 37 for cooperating with the drive connector 31 (see figure 1). As an example the attachment 37 is an integral part of the endcap 32.

The motorized roller 3M has a drive unit 35, in particular an electric motor, located within the roller tube 39. A clutch 36 (in particular non-switchable) connects an output shaft of the drive unit 35 with the roller tube 39. The drive unit 35 may comprise a geared transmission.

The control unit 310 comprises a frequency converter 312 and is adapted to provide the drive unit 35 with a motor current IM according to the operational conditions.

Reference is now made to figure 13 showing a simplified control loop. Conventionally the control unit 310 is adapted to regulate operation of the drive unit in a manner so that the drive unit drives 35 the roller tube 39 at a certain rotational speed, e.g. by providing a speed setpoint value for the conveying speed (the target speed vt). Regulation of the drive unit 35 is therefore based on said target speed vt. If a mechanical load acting against the drive unit, an actual speed v may be reduced compared to the target speed vt. The control unit by means of a regulator R initiates that the drive unit provides increased torque to keep the roller tube at a rotation speed according to the target speed vt to keep a speed difference dv=vt - v as low as possible, in the best case at Zero.

Figure 14 shows during normal operation the torque provided by the drive unit in response to the certain speed difference in the control loop of figure 13. In case that the speed difference is increasing, the motor current and in the same manner the motor torque T is increasing, until the components reach a design-related maximum (see point P2 in figure 13). This is the second mode of operation M2, which is for most rollers the normal mode of operation.

The torque T provided by the drive unit is in main proportional to the motor current provided by the frequency converter 312.

During operation a set of operation parameters 311 are provided to the control unit 310 from outside the roller tube 39 by a data connection 38, e.g. a wired data connection.

The set of operation parameters 311 may comprise a start stop I signal and said set point value for the drive speed.

According to invention the set of operation parameters 311 comprises also a setpoint for the maximum torque, which is relevant for the first mode of operation M1 , which is also referred to as a safety mode of operation.

The control unit is adapted to control the drive unit 35 in a manner that for safety reason the torque provided by the roller does to exceed the a setpoint value Tmax. Important is, that the motorized roller 3M, from a design-related point of view, is generally suitable to provide more power as long as not limited by the set point value Tmax. As the speed difference dv is increasing, also the torque t provided by the motor controlled by the control loop is increasing up to a point P1 , where the torques reaches the set point values Tmax, which is lower than the possible torque in the second mode of operation M2 (see figure 15).

That leads to the possibility to operate the motorized roller in at least two different modes of operation M1 , M2. In a first mode of operation the drive unit 35 is operating in a limited mode. A torque provided by the motorized roller is limited to a first set point value Tmax.

In a second mode of operation the torque provided can be larger than the first set point value Tmax. The motorized roller 3M is adapted to be switched between the two modes of operation. A switching command can be the set of parameters 311, when the parameter setpoint value has been changed to a previous value. As sons as the control unit receives an amended value, the motorized roller is switched from one mode into the another mode of operation. List of reference signs

1 conveyor arrangement

2 conveyor zone

3 conveyor roller

3M motor-driven conveyor roller

4 support frame

5 presence sensor

61 first safety feature I filler plate

62 second safety feature I closed side guide

63 third safety feature I drive torque limitation

7 PC, personal computer

8 IT tool I layouter

9 object to be conveyed

11 local zone controller

12 PLC

13 bus connection

31 drive connector

32 endcap

33 bearing

34 shaft

35 motor

36 clutch

37 attachment for drive connector

38 wire

39 roller tube 310 control unit 311 operation parameter 312 frequency converter

81 construction area

82 selection area

83 graphical representation of a component

84 human working space definition box

85 safety feature selection box C conveyor as an example of a conveyor area d conveying direction D destination as an example of a conveyor area F feed in station as an example of a conveyor area

I inlet

J junction

M merge

O outlet

III user interaction f finger

G gap between two rollers g smaller gap between roller and filler plate

T drive torque

Tmax maximum torque

IM motor current

SA safety area I human working space

Sc conveyor surface

M1 ,M2 first, second mode of operation v speed vt target speed dv speed difference between target speed and speed

Claims

1. Method of planning a conveyor arrangement (1), the conveyor arrangement is adapted to convey an object (9) from at least one first location (F) to at least one second location (D); wherein during intended use of the operation an operator interacts with said object (9) located within the conveyor arrangement (1) within a human working space (SA); the method comprising the step of providing an IT planning tool (8) for usage by a user; wherein by using the IT planning tool (8), representations (83) of a plurality of conveyor components, in particular conveyor zones (2), are arranged in a manner to form a representation of said conveyor arrangement (1); characterized in that the IT planning tool (8) is adapted to distinguish the areas (C, D, F) of the conveyor arrangement (1) between non-human working spaces and human working space (SA).

2. Method according to the preceding claim, characterized in that the IT planning tool (8) is adapted to add a human working space (SA) definition and/or withdraw said human working space (SA) definition to a conveyor area (C, D, F).

3. Method according to the preceding claim, characterized in that based on an input, in particular a user interaction (III), the IT planning tool (8) adds or withdraws said human working space definition to I from said conveyor area (C, D, F).

4. Method according any of the claims 2 to 3, characterized in that based on the definition as a human working space (SA) the IT planning tool (8) initiates design changes of the conveyor area (C, D, F), which is defined as a human working space.

5. Method according to the preceding claim, characterized in that initiating means, that based on said definition, the IT planning tool (8)

- performs a design change to the representation (83) of the conveyor arrangement (1) in the area defined as a human working space, and/or

- provides a design change proposal for selecting I deselecting by the user, where based on the selecting I deselecting the design change is performed in the representation (83) of the conveyor arrangement (1) in the area defined as a human working space; in particular where the design change is available for displaying in a construction area (81) of the IT planning tool (8).

6. Method according to the preceding claim, characterized in that the design change comprises the introduction of at least one safety feature into the conveyor arrangement (1) in the conveyor area defined as a human working space (SA).

7. Method according the preceding claims, characterized in that the safety feature comprises a mechanical safety device, in particular a finger protection such as a gap filler plate (61) or a closed side guide (62).

8. Method according claim 6 or 7, characterized in that the safety feature comprises an operational parameter (63), in particular a threshold value.

9. Method according to claim 8, characterized in that the operational parameter (63) is a fixed operational parameter, e.g. a construction based limitation.

10. Method according to claim 8, characterized in that the operational parameter (63) is a variable operational parameter, e.g. a control parameter.

11. Method according to any of the preceding claim wherein the human working space is an area of the conveyor arrangement where

- a human loads and/or unloads an object conveyed to I from the conveyor arrangement, and/or

- a human modifies an object located on the conveyor; in particular wherein, loading, unloading and/or modifying is performed with manual contact between the human and the object located on the conveyor.

12. Conveyor arrangement (1), the conveyor arrangement (1) is adapted to convey an object (9) from at least one first location (F) to at least one second location (D); in particular wherein during intended use of the operation an operator interacts with said object (9) located within the conveyor arrangement (1); the conveyor arrangement (1) comprises at least one roller conveyor zone (2) having a plurality of conveyor rollers (3) comprising at least one motorized conveyor roller (3M), wherein the motorized roller (3M) has a roller tube (39) and an electric drive unit (35) located within the roller tube (39), wherein the roller tube (39) comprises an outer surface which is constituting a part of a conveying surface (SC) of the conveyor zone (2), wherein the roller tube comprises a frequency converter (312) which outputs a motor current (IM) to the electric drive unit (35), wherein depending on the amount of electric current the drive unit (35) generates a mechanical drive torque (T); wherein the amount of electric current (T) is determined by a regulator (R), which compares an actual speed (v) of the drive unit with a target speed (vt), wherein based on the comparison, the frequency converter varies the amount of current put out to the drive unit (35), characterized in that the frequency converter (312) is adapted upon request to selectively limit the motor current provided to the drive unit (35) according to a setpoint value (Tmax), limiting a maximum torque provided by the motorized roller (3M).

13. Conveyor arrangement (1) according to the preceding claim, characterized in that the motorized roller (3M) is adapted to be switched between a first mode (M1) of operation and a second mode of operation (M2); wherein in the first mode of operation (M1) the drive unit (35) is operating in a limited mode, where a torque provided by the motorized roller is limited to a first set point value (Tmax);c wherein in a second mode of operation (M2) the drive unit (35) is adapted to operate so that a maximum torque provided by the motorized roller is larger than the first set point value (Tmax).

14. Conveyor arrangement (1) according to the preceding claim, characterized in that within the second mode of operation the drive unit (35) is adapted to operate

- either in another limited mode, where a maximum torque provided by the motorized roller is limited to a second set point value wherein the second set point value is larger than the first set point value;

- or in a non-limited mode, where a torque provided by the motorized roller is not limited by a setpoint value.

15. Conveyor arrangement (1) according to claim 13 or 14, characterized in that the motorized roller (3M) is adapted to receive a switching signal (311) from outside of the motorized roller (3M) via a data connection (38); wherein based on the switching signal the motorized roller is adapted to switch between the first mode of operation and the second mode of operation.