Method for monitoring a conveyor system and conveyor system

Abstract

Conveyor system comprising a conveyor chain with a plurality of connected chain links and a support structure arranged for supporting the conveyor chain. The conveyor chain is arranged as an endless conveyor chain structure configured for moving relative to the support structure in a transporting direction. The conveyor chain comprises a first detection element and a second detection element, where the first detection element and the second detection element are separated from each other along the conveyor chain. The conveyor system comprises a first sensor unit and a second sensor unit arranged in positions relative to the conveyor chain where simultaneously the first detection element is adjacent to the first sensor unit and the second detection element is adjacent to the second sensor unit. The first sensor unit is configured for detecting an initial passage of the first detection element at an initial time, and the second sensor unit is configured for detecting an initial passage of the second detection element at the initial time. The first sensor unit is configured for detecting a following passage of the first detection element at a detection time after the initial time, and the second sensor unit is configured for detecting a following passage of the second detection element at the detection time after the initial time. The conveyor system is configured for determining a first time offset between the initial passage of the first detection element and the initial passage of the second detection element, and determining a second time offset between the following passage of the first detection element and the following passage of the second detection element, where a difference between the first time offset and the second time offset is indicative of a deviating condition of the conveyor chain.

Description

[0001] METHOD FOR MONITORING A CONVEYOR SYSTEM AND CONVEYOR SYSTEM TECHNICAL FIELDThe present disclosure relates to a method for monitoring a conveyor systemcomprising a conveyor chain with a plurality of connected chain links and a support structure arranged for supporting the conveyor chain. The conveyor chain is arranged as an endless conveyor chain structure configured for moving relative to the support structure in a transporting direction. The disclosure further relates to a conveyor system comprising a conveyor chain with a plurality of connected chain links and a support structure arranged for supporting the conveyor chain. BACKGROUND Conveyor systems comprising a conveyor chain with a plurality of connected chainlinks are commonly used for transporting objects in different applications, such as forexample when moving objects between different stations in warehouses or manufacturing plants. The objects may be transported directly on the conveyor chainor alternatively via carrying means, such as pallets or pucks.To have an optimized performance of the conveyor chains, the chains need to beinspected or replaced at regular intervals to avoid unwanted deviating conditions ofthe conveyor chains, such as unwanted extensions of the conveyor chains. Thecomponents of the conveyor chains are subject to wear during their operation, andespecially wear affecting friction surfaces and connections between the chain linksare critical during extended use of the conveyor chains. This wear may causeprogressive elongation of the conveyor chains, which may lead to improper operations of the conveyor chains. The conveyor chains are often inspected manually, which lead to time-consuming operations and cause undesired downtime of the conveyor systems. There is thus a need for a more efficient way for determining deviating conditions of the conveyor chain. SUMMARY An object of the present disclosure is to provide a method for monitoring a conveyorsystem and a conveyor system where the previously mentioned problems areavoided. This object is at least partly achieved by the features of the independentclaims. The dependent claims contain further developments of the method formonitoring a conveyor system and the conveyor system.The disclosure concerns a method for monitoring a conveyor system comprising aconveyor chain with a plurality of connected chain links and a support structurearranged for supporting the conveyor chain. The conveyor chain is arranged as anendless conveyor chain structure configured for moving relative to the supportstructure in a transporting direction. The conveyor chain comprises a first detectionelement and a second detection element, where the first detection element and thesecond detection element are separated from each other along the conveyor chain.The conveyor system comprises a first sensor unit and a second sensor unit arrangedin positions relative to the conveyor chain where simultaneously the first detectionelement is adjacent to the first sensor unit and the second detection element isadjacent to the second sensor unit. The method comprises the steps: detecting aninitial passage of the first detection element by the first sensor unit and an initial passage of the second detection element by the second sensor unit at an initial time; detecting a following passage of the first detection element by the first sensor unit and a following passage of the second detection element by the second sensor unit at a detection time after the initial time; determining a first time offset between the initial passage of the first detection element and the initial passage of the second detection element, and determining a second time offset between the following passage of the first detection element and the following passage of the second detection element, wherein a difference between the first time offset and the second time offset is indicative of a deviating condition of the conveyor chain.Advantages with these method steps are that by determining the deviating conditionof the conveyor chain, operational issues with the conveyor system are efficientlyprevented. The amount of manual inspection of the conveyor chain can be minimized, leading to more time efficient operation of the conveyor system and less undesired downtime of the conveyor system. The deviating condition may be different for different conveyor systems and depends for example on the configurations on the conveyor chain, the chain links, and the support structure. During extended use of the conveyor system, the components of the conveyor chain are subject to wear, and especially wear affecting friction surfaces and connections between the chain links are critical during extended use of the conveyor chain. Such wear may cause progressive elongation of the conveyor chain, which may lead to improper operation of the conveyor chain. If the conveyor chain has a deviating condition beyond a specific threshold value at the detection time, the operation of the conveyor system may be non-optimal and such a deviating condition could indicate that there is a needfor restoring the conveyor chain or alternatively replace the conveyor chain. Typicalconditions of the conveyor chain after extended use are pitch values of the conveyorchain that are greater than an initial pitch and length values of the conveyor chain thatare greater than an initial length.In one embodiment, the conveyor chain comprises a first chain link cluster formed by a plurality of connected cluster chain links following directly after each other, and a second chain link cluster formed by a plurality of connected cluster chain linksfollowing directly after each other. The first chain link cluster and the second chainlink cluster are separated from each other along the conveyor chain. The first chain link cluster comprises the first detection element and the second chain link clustercomprises the second detection element. A chain link cluster may be defined as apre-defined group of two or more connected chain links following directly after each other along the conveyor chain, and each chain link in the chain link cluster is definedas a cluster chain link. By grouping the chain links into clusters, the conveyor systemmay detect different parameters related to the operation of the conveyor system. In one embodiment, one or more of the cluster chain links of the first chain link cluster are arranged as detectable chain links each comprising a detection element. One or more of the cluster chain links of the second chain link cluster are arranged asdetectable chain links each comprising a detection element. The method furthercomprises the steps: detecting the detectable chain links of the first chain link cluster by the first sensor unit and detecting the detectable chain links of the second chain link cluster by the second sensor unit. In embodiments, the first chain link cluster comprises two or more detectable chain links, and / or the second chain link cluster comprises two or more detectable chainlinks. By detecting two or more of the detectable chain links of the first chain linkcluster by the first sensor unit and detecting the detectable chain links of the second chain link cluster by the second sensor unit, the detections could be used for determining other parameters of the conveyor chain, such as speed parameters. In embodiments, consecutive pairs of the two or more detectable chain links of the first chain link cluster are separated by one or more non-detectable chain links; and / or consecutive pairs of the two or more detectable chain links of the second chain linkcluster are separated by one or more non-detectable chain links. By using non-detectable chain links between the detectable chain links, the spacing between thedetectable chain links can be increased for a more precise determination of conveyorchain parameters, such as speed parameters. In embodiments, the method further comprises the steps: detecting at least two of the two or more detectable chain links in the first chain link cluster by the first sensor unit and based on the detection determining a first speed of the first chain link cluster; and / or detecting at least two of the two or more detectable chain links in the second chain link cluster by the second sensor unit and based on the detection determininga second speed of the second chain link cluster. By detecting the speeds of the chainlink clusters, further parameters of the conveyor system can be determined, such as potential issues with the conveyor chain or the drive unit used for driving the conveyor chain.In embodiments, the conveyor chain is configured with an initial pitch at the initial time.The method further comprises the steps: measuring a passage time betweenpassages of the detected at least two of the two or more detectable chain links in the first chain link cluster at the initial time, and determining an initial first speed of the first chain link cluster based on the measured passage time and the initial pitch; and / or measuring a passage time between passages of the detected at least two of the two or more detectable chain links in the second chain link cluster at the initial time, and determining an initial second speed of the second chain link cluster based on themeasured passage time and the initial pitch. In this way, the respective initial speedscan be calculated by detecting the passage time between the sensor unit detections of the detection elements in the respective chain link clusters when the distances between the detection elements are known. When the first initial speed of the first chain link cluster and the second initial speed of the second chain link cluster are known, deviating speed values at a later time may indicate potential issues with the conveyor chain or the drive unit used for driving the conveyor chain.In embodiments, the conveyor chain comprises one or more further chain link clustersformed by a plurality of connected cluster chain links following directly after eachother. One or more of the cluster chain links of the one or more further chain linkclusters are arranged as detectable chain links, each comprising a detection element.The method further comprises the step: detecting the detectable chain links of the one or more further chain link clusters by the first sensor unit and / or the second sensorunit. By arranging the further chain link cluster at a suitable distance from the firstchain link cluster, also the first chain link cluster and the further chain link cluster may be used for determining the deviating condition. Similarly, by arranging the further chain link cluster at a suitable distance from the second chain link cluster, also the second chain link cluster and the further chain link cluster may be used for determining the deviating condition.In one embodiment, the deviating condition of the conveyor chain is an extension ofthe conveyor chain from an initial length. At the initial time, the conveyor chain has aninitial length, and a condition of the conveyor chain deviating from the initial length to a certain degree may be considered an unwanted deviating condition. The deviating condition of the conveyor chain may thus be an extension of the conveyor chain from the initial length.The disclosure further concerns a conveyor system comprising a conveyor chain witha plurality of connected chain links and a support structure arranged for supportingthe conveyor chain. The conveyor chain is arranged as an endless conveyor chainstructure configured for moving relative to the support structure in a transportingdirection. The conveyor chain comprises a first detection element and a seconddetection element, where the first detection element and the second detectionelement are separated from each other along the conveyor chain. The conveyorsystem comprises a first sensor unit and a second sensor unit arranged in positionsrelative to the conveyor chain where simultaneously the first detection element isadjacent to the first sensor unit and the second detection element is adjacent to thesecond sensor unit. The first sensor unit is configured for detecting an initial passageof the first detection element at an initial time, and the second sensor unit is configuredfor detecting an initial passage of the second detection element at the initial time. The first sensor unit is configured for detecting a following passage of the first detection element at a detection time after the initial time, and the second sensor unit is configured for detecting a following passage of the second detection element at thedetection time after the initial time. The conveyor system is configured for determininga first time offset between the initial passage of the first detection element and the initial passage of the second detection element, and determining a second time offsetbetween the following passage of the first detection element and the followingpassage of the second detection element, where a difference between the first timeoffset and the second time offset is indicative of a deviating condition of the conveyor chain. Advantages with these features are that by determining the deviating condition of theconveyor chain, operational issues with the conveyor system are efficiently prevented.The deviating condition may be different for different conveyor systems and depends for example on the configurations on the conveyor chain, the chain links, and the support structure. During extended use of the conveyor system, the components of the conveyor chain are subject to wear, and especially wear affecting friction surfaces and connections between the chain links are critical during extended use of the conveyor chain. Such wear may cause progressive elongation of the conveyor chain, which may lead to improper operation of the conveyor chain. If the conveyor chain has a deviating condition beyond a specific threshold value at the detection time, the operation of the conveyor system may be non-optimal and such a deviating condition could indicate that there is a need for restoring the conveyor chain or alternativelyreplace the conveyor chain. Typical conditions of the conveyor chain after extendeduse are pitch values of the conveyor chain that are greater than an initial pitch and length values of the conveyor chain that are greater than an initial length. In one embodiment, the first detection element and the second detection element are arranged at a distance from each other along the conveyor chain corresponding to adistance between the first sensor unit and the second sensor unit. The positions ofthe first sensor unit and the second sensor unit may be calibrated relative to the support structure to achieve a correct positioning between the respective sensor units and detection elements. In one embodiment, the first detection element and the second detection element areseparated from each other along the conveyor chain by a first separation distanceformed by a plurality of chain links following directly after each other and a secondseparation distance formed by a plurality of chain links following directly after eachother. In one embodiment, the first separation distance is extending in the transporting direction from the first detection element to the second detection element, and the second separation distance is extending in the transporting direction from the second detection element to the first detection element.In one embodiment, the conveyor chain comprises a first chain link cluster formed bya plurality of connected cluster chain links following directly after each other, and a second chain link cluster formed by a plurality of connected cluster chain linksfollowing directly after each other. The first chain link cluster and the second chainlink cluster are separated from each other along the conveyor chain. The first chain link cluster comprises the first detection element and the second chain link clustercomprises the second detection element. A chain link cluster may be defined as apre-defined group of two or more connected chain links following directly after each other along the conveyor chain, and each chain link in the chain link cluster is definedas a cluster chain link. By grouping the chain links into clusters, the conveyor systemmay detect different parameters related to the operation of the conveyor system. In one embodiment, one or more of the cluster chain links of the first chain link clusterare arranged as detectable chain links each comprising a detection element. One ormore of the cluster chain links of the second chain link cluster are arranged asdetectable chain links each comprising a detection element. The first sensor unit isconfigured for detecting the detectable chain links of the first chain link cluster and the second sensor unit is configured for detecting the detectable chain links of the second chain link cluster.In embodiments, the first chain link cluster comprises two or more detectable chainlinks, and / or the second chain link cluster comprises two or more detectable chainlinks. By detecting two or more of the detectable chain links of the first chain linkcluster by the first sensor unit and detecting the detectable chain links of the second chain link cluster by the second sensor unit, the detections could be used for determining other parameters of the conveyor chain, such as speed parameters. In embodiments, consecutive pairs of the two or more detectable chain links in the first chain link cluster are separated by one or more non-detectable chain links, and / or consecutive pairs of the two or more detectable chain links in the second chain linkcluster are separated by one or more non-detectable chain links. By using non-detectable chain links between the detectable chain links, the spacing between thedetectable chain links can be increased for more precise parameter determinations.In embodiments, the first sensor unit is configured for detecting at least two of the two or more detectable chain links in the first chain link cluster and based on the detection determining a first speed of the first chain link cluster, and / or the second sensor unit is configured for detecting at least two of the two or more detectable chain links in the second chain link cluster and based on the detection determining a second speed ofthe second chain link cluster. By detecting the speeds of the chain link clusters, furtherparameters of the conveyor system can be determined, such as potential issues with the conveyor chain or the drive unit used for driving the conveyor chain. In embodiments, the conveyor chain comprises one or more further chain link clusters formed by a plurality of connected cluster chain links following directly after eachother. One or more of the cluster chain links of the one or more further chain linkclusters, are arranged as detectable chain links, each comprising a detection element.The first sensor unit and / or the second sensor unit are configured for detecting thedetectable chain links of the one or more further chain link clusters. By arranging thefurther chain link cluster at a suitable distance from the first chain link cluster, also the first chain link cluster and the further chain link cluster may be used for determining the deviating condition. Similarly, by arranging the further chain link cluster at a suitable distance from the second chain link cluster, also the second chain link cluster and the further chain link cluster may be used for determining the deviating condition. In one embodiment, the first sensor unit and second sensor unit are attached to thesupport structure. This arrangement of the sensor units are enabling efficientpositioning relative to the support structure for an easy calibration of the conveyor system. In one embodiment, the conveyor chain is configured with an initial pitch at the initialtime. The initial pitch is suitably used for determining the initial speeds of the chainlink clusters. The respective initial speeds can be calculated by detecting the passage time between the sensor unit detections of the detection elements in the respective chain link clusters when the distances between the detection elements are known. Deviating speed values at a later time may indicate potential issues with the conveyor chain or the drive unit used for driving the conveyor chain. In one embodiment, the deviating condition of the conveyor chain is an extension ofthe conveyor chain from an initial length. At the initial time, the conveyor chain has aninitial length, and a condition of the conveyor chain deviating from the initial length to a certain degree may be considered an unwanted deviating condition. The deviating condition of the conveyor chain may thus be an extension of the conveyor chain from the initial length. BRIEF DESCRIPTION OF DRAWINGSThe disclosure will be described in detail in the following, with reference to theattached drawings, in whichFig. 1a-b show schematically, in a perspective view and in a view from above, aconveyor system comprising a conveyor chain arranged as an endless conveyor chain structure with a plurality of connected chain links and a support structure arranged for supporting the conveyor chain,Fig. 2a-c show schematically, in a perspective view and in side views, theconveyor system with sensor units arranged in connection to the conveyor chain and detection elements arranged in the conveyor chain,Fig.3a-d show schematically, in side views, the conveyor chain with positions ofthe detection elements relative to the sensor units,Fig.4a-b show schematically, in side views, an embodiment of the conveyorchain, where the conveyor chain comprises a first chain link cluster formed by a plurality of connected cluster chain links and a second chain link cluster formed by a plurality of connected cluster chain links,Fig.5a-b show schematically, in side views, an alternative embodiment of theconveyor chain, where the conveyor chain comprises a first chain link cluster formed by a plurality of connected cluster chain links and a second chain link cluster formed by a plurality of connected cluster chain links,Fig.6a-b show schematically, in side views, further alternative embodiments ofthe conveyor chain, where the conveyor chain comprises a first chain link cluster formed by a plurality of connected cluster chain links and a second chain link cluster formed by a plurality of connected cluster chain links, andFig. 7 shows schematically, in side views, an embodiment of the conveyorchain, where the conveyor chain comprises a first chain link cluster formed by a plurality of connected cluster chain links, a second chain link cluster formed by a plurality of connected cluster chain links, and a further chain link cluster formed by a plurality of connected cluster chain links. DESCRIPTION OF EXAMPLE EMBODIMENTS Various aspects of the disclosure will hereinafter be described in conjunction with the appended drawings to illustrate and not to limit the disclosure, wherein like designations denote like elements, and variations of the described aspects are not restricted to the specifically shown embodiments, but are applicable on other variations of the disclosure. Those skilled in the art will appreciate that the steps, services and functions explained herein may be implemented using individual hardware circuitry, using software functioning in conjunction with a programmed microprocessor or general purposecomputer, using one or more Application Specific Integrated Circuits (ASICs) and / orusing one or more Digital Signal Processors (DSPs). It will also be appreciated that when the present disclosure is described in terms of a method, it may also be embodied in one or more processors and one or more memories coupled to the one or more processors, wherein the one or more memories store one or more programs that perform the steps, services and functions disclosed herein when executed by the one or more processors.Figures 1a-b schematically show a conveyor system S comprising a conveyor chain1 with a plurality of connected chain links 2 and a support structure 3 arranged for supporting the conveyor chain 1. The conveyor chain 1 is arranged as an endless conveyor chain structure that is moving relative to the support structure 3 in a transporting direction DT. The conveyor chain 1 is suitably used for transporting objects from one position to another position along the endless conveyor chainstructure. The conveyor chain 1 is suitably driven by a non-illustrated drive unit via adrive shaft 6, and commonly one or more electric motors are used as the drive unit. Acontrol unit 7 is used for controlling the operation of the conveyor system S. The plurality of chain links 2 are connected to each other with suitable connectionelements, such as connecting pins, to form the conveyor chain 1 into the endlessconveyor chain structure. The chain links 2 may have different designs andconfigurations depending on the configuration of the conveyor chain 1, and the typeof objects that are transported. In the shown embodiment, the conveyor system S isarranged with an upper side SUfor transporting the objects and a lower side SLconstituting a return path for the conveyor chain 1, as understood from figures 1a-b. The support structure 3 is arranged between the upper side SUand the lower side SL, and in this way, the conveyor chain 1 is extending around the support structure 3. It should be understood that the conveyor chain 1 and the support structure 3 may have other configurations, such as an horizontally arranged conveyor chain structures with bends for forming the endless conveyor chain structure.As further indicated in figures 1a-b and shown in figures 2a-c, the conveyor system Scomprises a first sensor unit 4a and a second sensor unit 4b arranged in different positions relative to the conveyor chain 1. Suitably, the first sensor unit 4a and the second sensor unit 4b are attached to the support structure 3. The first sensor unit 4a and the second sensor unit 4b are used for detecting detection elements 5 arranged in the conveyor chain 1. The sensors may have any suitable configuration, such as for example optical sensors for detecting optical detection elements, magnetic sensors for detecting magnetic detection elements, inductive sensors for detecting metallic detection elements. Other suitable sensors are for example electro- mechanical sensors, capacitive sensors, photoelectric sensors, and ultrasonic sensors. Further suitable sensor types are for example sensors using QR codes, barcodes, or data grids, with corresponding scanners. Alternatively, sensors using RFID tags or NFC tags with corresponding scanners may be used. In the shown embodiment, the second sensor unit 4b is arranged near the drive end of the conveyor system S in connection to the drive shaft 6, and the first sensor unit 4a is arranged near a non-driven idler unit used for returning the conveyor chain 1 from the lower side SLto the upper side SU.In the embodiment shown in figures 2a-c, the conveyor chain 1 comprises a firstdetection element 5a and a second detection element 5b, each arranged in a chainlink 2. The detection elements may for example be attached to an outer surface of acorresponding chain link 2 or embedded in a corresponding chain link 2, dependingon the type of sensor units and detection elements used. The first detection element5a and the second detection element 5b are separated from each other along the conveyor chain 1.As understood from figures 2a-c, the first sensor unit 4a and the second sensor unit4b are arranged in positions relative to the conveyor chain 1, such that simultaneouslythe first detection element 5a is adjacent to the first sensor unit 4a and the second detection element 5b is adjacent to the second sensor unit 4b. In this way, the first sensor unit 4a is detecting a passage of the first detection element 5a and the secondsensor unit 4b is detecting a passage of the second detection element 5b. To achievethis, the first detection element 5a and the second detection element 5b are arranged at a distance from each other along the conveyor chain 1 corresponding to a distancebetween the first sensor unit 4a and the second sensor unit 4b, as illustrated by theposition of the conveyor chain 1 relative to the sensor units in figures 2a-c. Thepositions of the first sensor unit 4a and the second sensor unit 4b may be calibratedrelative to the support structure 3 to achieve a correct positioning between the respective sensor units and detection elements. As shown in figure 2c, the first detection element 5a and the second detection element 5b are separated from each other along the conveyor chain 1 by a first separation distance D1 formed by a plurality of chain links 2 following directly after each other, and a second separation distance D2 formed by a plurality of chain links 2 following directly after each other. In the shown embodiment, the first separation distance D1 is extending in the transporting direction DT from the first detection element 5a to the second detection element 5b, and the second separation distance D2 is extending in the transporting direction DT from the second detection element 5b to the first detection element 5a.Upon operation of the conveyor system S, the first sensor unit 4a is configured fordetecting an initial passage PIof the first detection element 5a at an initial time TINand the second sensor unit 4b is configured for detecting an initial passage PIof the second detection element 5b at the initial time TIN, as schematically shown in figure3a. The initial time TIN is suitably referring to a time where the conveyor chain 1 isnew, or has been restored into a new condition. At the initial time TIN, the conveyorchain 1 has an initial length LINand an initial pitch PIN, and a condition of the conveyor chain 1 deviating from the initial length LINand the initial pitch PINto a certain degree may be considered an unwanted deviating condition CD. The pitch is in this contextreferring to the spacing between the individual chain links 2, and may suitably bemeasured as the spacing between connection elements of two adjacent chain links 2. The deviating condition CDof the conveyor chain 1 may thus be an extension of the conveyor chain 1 from the initial length LIN. Alternatively, the initial time TINis referring to a reference time after initiated use of the conveyor chain 1, from which the deviating condition should be measured. It could for example be desirable to operate the conveyor system S for a specific period and then calibrate the system for optimal performance, and the initial time TINmay then bedetermined as the time after such a calibration operation. In other embodiments, theinitial time TIN is determined as any suitable time during operation of the conveyor system S. The deviating condition CD may be different for different conveyor systems S and may for example depend on the configurations on the conveyor chain 1, the chain links 2 with their connection elements, and the support structure 3. If the conveyor chain 1 has a deviating condition CD beyond certain threshold values that are depending on the configuration of the conveyor system S, the operation of the conveyor system S is non-optimal. The threshold value is suitably determined for the specificconfiguration of the conveyor system S. During extended use of the conveyor system S, the components of the conveyor chain 1 are subject to wear, and especially wear affecting friction surfaces and connections between the chain links 2 are critical during extended use of the conveyor chain 1. Such wear may cause progressive elongation of the conveyor chain 1, which may lead to improper operation of the conveyor chain1. Typical conditions of the conveyor chain 1 after extended use are thus pitch valuesthat are deviating from the initial pitch PIN and length values that are deviating from the initial length LIN.At the initial time TIN, the conveyor system S is calibrated such that the first sensorunit 4a and the second sensor unit 4b are arranged in positions relative to the conveyor chain 1, such that simultaneously the first detection element 5a is adjacent to the first sensor unit 4a and the second detection element 5b is adjacent to thesecond sensor unit 4b. In this way, upon operation of the conveyor system S at theinitial time TIN, the first sensor unit 4a is detecting the initial passage PI of the firstdetection element 5a and the second sensor unit 4b is detecting the initial passage PIof the second detection element 5b simultaneously, or almost simultaneously. Theinitial passage PIof the first detection element 5a and the initial passage PIof the second detection element 5b past the respective sensor units are taking place duringthe same lap or revolution of the conveyor chain 1. It should however be understoodthat due to tolerances there might be a minor time difference between the initialpassage PIof the first detection element 5a past the first sensor unit 4a and the initial passage PIof the second detection element 5b past the second sensor unit 4b. Thistime difference at the initial time TIN is referred to as the first time offset TO1. Suitably,the control unit 7 of the conveyor system S is determining the first time offset TO1between the initial passage PIof the first detection element 5a and the initial passagePI of the second detection element 5b. In very specific conditions, the first sensor unit4a may detect the initial passage PI of the first detection element 5a and the second sensor unit 4b the initial passage PI of the second detection element 5b at exactly the same time, and then the first time offset TO1 is zero. The initial time TIN is exemplified in figure 3c, and as understood from the figure there is a minor first time offset TO1 between the initial passage PI of the first detection element 5a past the first sensor unit 4a and the initial passage PI of the second detection element 5b past the second sensor unit 4b. In figure 3c, when the first sensor unit 4a is detecting the first detection element 5a, the second detection element 5b has not yet fully reached the second sensor unit 4b. The short period in time between the detection of the initial passage PI of the first detection element 5apast the first sensor unit 4a, and the later detection of the initial passage PI of thesecond detection element 5b past the second sensor unit 4b, is defining the first time offset TO1.Upon further operation of the conveyor system S, the first sensor unit 4a is configuredfor detecting a following passage PFO of the first detection element 5a at a detection time TDafter the initial time TINand the second sensor unit 4b is configured for detecting a following passage PFOof the second detection element 5b at the detectiontime TD after the initial time TIN, as schematically shown in figure 3b. In this way, thestatus of the conveyor chain 1 may be monitored after the initial time TIN, as will be further described below.The detection time TD is suitably referring to a time after the initial time TIN where theconveyor system S has been operated for a shorter or longer period of time, and there is a need for determining if the conveyor chain 1 is still in good condition. At the detection time TD, the conveyor chain 1 may have a length that is deviating from theinitial length LIN and a pitch that is deviating from the initial pitch PIN. As describedabove, during use of the conveyor system S, the components of the conveyor chain 1 are subject to wear, and especially wear affecting friction surfaces and connections between the chain links 2 are critical during extended use of the conveyor chain 1. Such wear may cause progressive elongation of the conveyor chain 1, which maylead to improper operation of the conveyor chain 1. A condition of the conveyor chain1 deviating from the initial length LINand the initial pitch PINto a certain degree may be considered an unwanted deviating condition CD. The detection time TDmay be any time after the initial time TIN, and in specific embodiments, the conveyor system S iscontinuously or intermittently monitoring the status of the conveyor chain 1 after theinitial time TIN. In this way, several detection times TD may follow after each other. Iffor example detecting every passage of the detection elements by the respective sensor units after the initial time TIN, or passages of the detection elements by therespective sensor units at certain time intervals after the initial time TIN, deteriorationover time of the conveyor chain 1 could be monitored. If the conveyor chain 1 has adeviating condition CD beyond a specific threshold value at the detection time TD, theoperation of the conveyor system S may be non-optimal and such a deviating condition CD could then indicate that there is a need for restoring the conveyor chain1 or alternatively replace the conveyor chain 1. Typical conditions of the conveyorchain 1 after extended use are pitch values of the conveyor chain 1 that are greater than the initial pitch PIN and length values of the conveyor chain 1 that are greater than the initial length LIN.At the detection time TD when operating the conveyor system S, the first sensor unit4a is detecting the following passage PFO of the first detection element 5a and the second sensor unit 4b is detecting the following passage PFOof the second detection element 5b. If there is an elongation of the conveyor chain at the detection time TD,there will be a time difference between the following passage PFO of the first detectionelement 5a past the first sensor unit 4a and the following passage PFOof the second detection element 5b past the second sensor unit 4b. This time difference at thedetection time TD is referred to as the second time offset TO2. Suitably, the control unit7 of the conveyor system S is determining the second time offset TO2 at the detectiontime TD, between the following passage PFO of the first detection element 5a and thefollowing passage PFOof the second detection element 5b. With the expressionfollowing passage PFO, is meant the corresponding passages of the first detectionelement 5a past the first sensor unit 4a and the second detection element 5b past thesecond sensor unit 4b at the detection time TD. The following passages PFO will thusbe detected during the same lap or revolution of the conveyor chain 1 at the detection time TDafter the initial time TIN. If for example the following passage PFOof the first detection element 5a is taking place after one thousand revolutions from the initial passage PIof the first detection element 5a, also the following passage PFOof the second detection element 5b is taking place after one thousand revolutions from the initial passage PI of the second detection element 5b. The detection time TD is exemplified in figure 3d, and as understood from the figurethere is a second time offset TO2 between the following passage PFO of the firstdetection element 5a past the first sensor unit 4a and the following passage PFO of the second detection element 5b past the second sensor unit 4b. In figure 3d, when the first sensor unit 4a is detecting the first detection element 5a, the second detection element 5b has already passed the second sensor unit 4b. The short period in time between the detection of the following passage PFO of the first detection element 5apast the first sensor unit 4a, and the earlier detection of the following passage PFO of the second detection element 5b past the second sensor unit 4b, is defining thesecond time offset TO2.The conveyor system S with the control unit 7 is as described above determining thefirst time offset TO1 between the initial passage PI of the first detection element 5a andthe initial passage PI of the second detection element 5b, and determining the secondtime offset TO2 between the following passage PFO of the first detection element 5aand the following passage PFO of the second detection element 5b. A differencebetween the first time offset TO1and the second time offset TO2is indicative of a deviating condition CDof the conveyor chain 1.In other embodiments, the conveyor chain 1 may comprise chain link clusters formedby a plurality of chain links 2. A chain link cluster may be defined as a pre-defined group of two or more connected chain links 2 following directly after each other along the conveyor chain 1. Each chain link 2 in the chain link cluster is defined as a cluster chain link 2CL. One or more of the cluster chain links 2CLmay be arranged as detectable chain links 2Deach comprising a detection element 5. One or more of the cluster chain links 2CLmay be arranged as non-detectable chain links 2NDarranged without any detection element 5. By grouping chain links 2 into clusters, the conveyor system S may detect different parameters related to the operation of the conveyor system S. The conveyor chain 1 may comprise a first chain link cluster C1 and a second chain link cluster C2. One or more of the cluster chain links 2CLof the first chain link cluster C1 may be arranged as detectable chain links 2D, each comprising a detection element 5. The first sensor unit 4a is with this arrangement of the first chain link cluster C1 configured for detecting the one or more detectable chain links 2Dof the first chainlink cluster C1. One or more of the cluster chain links 2CL of the second chain linkcluster C2 may be arranged as detectable chain links 2D each comprising a detectionelement 5. The second sensor unit 4b is with this arrangement of the second chainlink cluster C2 configured for detecting the one or more detectable chain links 2D of the second chain link cluster C2.In the embodiment exemplified in figures 4a-b, the conveyor chain 1 comprises a firstchain link cluster C1 formed by a plurality of connected cluster chain links 2CL following directly after each other, and a second chain link cluster C2 formed by a plurality ofconnected cluster chain links 2CL following directly after each other. In the shownembodiment, the first chain link cluster C1 comprises three cluster chain links 2CL following directly after each other, and the second chain link cluster C2 comprisesthree cluster chain links 2CL following directly after each other. The first chain linkcluster C1 and the second chain link cluster C2 are separated from each other alongthe conveyor chain 1, and the first chain link cluster C1 comprises a first detectionelement 5a and the second chain link cluster C2 comprises a second detectionelement 5b. The cluster chain link 2CL comprising the first detection element 5a isdefined as a detectable chain link 2D, and the cluster chain link 2CLcomprising the second detection element 5b is defined as a detectable chain link 2D. The other cluster chain links 2CLnot comprising detection elements 5 are defined as non-detectable chain links 2ND. The first sensor unit 4a is with this arrangement of the first chain link cluster C1 configured for detecting the detectable chain link 2Dwith the first detection element 5a of the first chain link cluster C1, and the second sensor unit 4b is with this arrangement of the second chain link cluster C2 configured for detecting the detectable chain link 2Dwith the second detection element 5b of the second chain link cluster C2.With the arrangement of the chain link clusters shown in figures 4a-b, the deviatingcondition CD may be detected as described in the embodiment above by determiningthe first time offset TO1and the second time offset TO2. At the initial time TIN, the conveyor system is configured such that the first sensor unit 4a and the second sensor unit 4b are arranged in positions relative to the conveyor chain 1, such that simultaneously the first detection element 5a of the first chain link cluster C1 is adjacent to the first sensor unit 4a and the second detection element 5b of the second chain link cluster C2 is adjacent to the second sensor unit 4b. In this way, when operating the conveyor system S at the initial time TIN, the first sensor unit 4a is detecting the initial passage PI of the first detection element 5a and the second sensor unit 4b is detecting the initial passage PI of the second detection element 5b simultaneously, or almost simultaneously. The non-detectable chain links 2ND may if desired be arranged with other types of sensors, such as for example strain gauge sensors. In other embodiments, each of the chain link clusters may comprise further detection elements 5, and the first chain link cluster C1 may comprise two or more detectable chain links 2D, and / or the second chain link cluster C2 may comprise two or moredetectable chain links 2D. If detecting at least two of the two or more detectable chainlinks 2D in the first chain link cluster C1 by the first sensor unit 4a, a first speed S1 of the first chain link cluster C1 can be determined based on the detection by the first sensor unit 4a. If detecting at least two of the two or more detectable chain links 2D in the second chain link cluster C2 by the second sensor unit 4b, a second speed S2 of the second chain link cluster C2 can be determined based on the detection by the second sensor unit 4b. These detections can be made at any time during theoperation of the conveyor system S.As described above, the conveyor chain 1 is configured with an initial pitch PINat the initial time TIN. By measuring a passage time TPbetween passages of the detected at least two of the two or more detectable chain links 2Din the first chain link cluster C1 at the initial time TIN, an initial first speed S1INof the first chain link cluster C1 based on the measured passage time TPand the initial pitch PINcan be determined. By measuring a passage time TPbetween passages of the detected at least two of the two or more detectable chain links 2Din the second chain link cluster C2 at the initial time TIN, an initial second speed S2INof the second chain link cluster C2 based on the measured passage time TPand the initial pitch PINcan be determined.In the alternative embodiment exemplified in figures 5a-b, the conveyor chain 1comprises a first chain link cluster C1 formed by a plurality of connected cluster chain links 2CLfollowing directly after each other, and a second chain link cluster C2 formed by a plurality of connected cluster chain links 2CLfollowing directly after each other. In this embodiment, the first chain link cluster C1 comprises three cluster chain links 2CLfollowing directly after each other, and the second chain link cluster C2 comprises three cluster chain links 2CL following directly after each other. The first chain link cluster C1 and the second chain link cluster C2 are separated from each other along the conveyor chain 1, and the first chain link cluster C1 comprises two detection elements 5 and the second chain link cluster C2 comprises two detection elements 5. Each detectable chain link 2D comprises a detection element 5, as described above.The first chain link cluster C1 thus comprises two detectable chain links 2D separatedby a non-detectable chain link 2ND, and the second chain link cluster C2 comprisestwo detectable chain links 2D separated by a non-detectable chain link 2ND. With thisconstruction of the conveyor chain 1, consecutive pairs of the two detectable chain links 2D in the first chain link cluster C1 are separated by one non-detectable chainlink 2ND, and consecutive pairs of the two detectable chain links 2D in the second chainlink cluster C2 are separated by one non-detectable chain link 2ND.With the arrangement of the conveyor chain 1 shown in figures 5a-b, one of thedetection elements 5 of the first chain link cluster C1 and one corresponding detection element 5 of the second chain link cluster C2 could be used for determining thedeviating condition CD, as described above by determining the first time offset TO1 andthe second time offset TO2. In this embodiment, the first sensor unit 4a is configuredfor detecting an initial passage PIand a following passage PFOof the leading detectionelement 5 of the first chain link cluster C1, and the second sensor unit 4b is configuredfor detecting an initial passage PI and a following passage PFO of the leading detectionelement 5 of the second chain link cluster C2. These detections may be used fordetermining the deviating condition CD. At the initial time TIN, as schematically shown in figure 5a, the conveyor system is configured such that the first sensor unit 4a and the second sensor unit 4b are arranged in positions relative to the conveyor chain 1, such that simultaneously the leading detection element 5 of the first chain link cluster C1 is adjacent to the first sensor unit 4a and the leading detection element 5 of the second chain link cluster C2 is adjacent to the second sensor unit 4b. In this way, when operating the conveyor system S at the initial time TIN, the first sensor unit 4a is detecting the initial passage PIof the leading detection element 5 of the first chain link cluster C1 and the second sensor unit 4b is detecting the initial passage PIof the leading detection element 5 of the second chain link cluster C2 simultaneously, or almost simultaneously. In this exemplified embodiment, the leading detection element 5 of the first chain link cluster C1 may be denoted a first detection element, and the leading detection element 5 of the second chain link cluster C2 may be denoted a second detection element, to correspond to the designations of the detectable chain links in the embodiment described in connection to figures 4a-b. In the embodiment shown in figures 5a-b, the first sensor unit 4a could further be configured for detecting a passage of the trailing detection element 5 of the first chain link cluster C1 and the second sensor unit 4b could further be configured for detecting a passage of the trailing detection element 5 of the second chain link cluster C2. Thus, the first sensor unit 4a is detecting the two detectable chain links 2D in the first chain link cluster C1, and the second sensor unit 4b is detecting the two detectable chain links 2D in the second chain link cluster C2. Based on the detection of the two detectable chain links 2D in the first chain link cluster C1 by the first sensor unit 4a, aninitial first speed S1IN of the first chain link cluster C1 can be determined if for examplethe initial pitch PIN of the conveyor chain 1 is known. Based on the detection of the two detectable chain links 2D in the second chain link cluster C2 by the second sensorunit 4b, an initial second speed S2IN of the second chain link cluster C2 can bedetermined if for example the initial pitch PIN of the conveyor chain 1 is known. Therespective speeds can be calculated by detecting the passage time TP between thesensor unit detections of the detection elements 5 in the respective chain link clusters when the distances between the detection elements are known. When the first initial speed S1INof the first chain link cluster C1 is known and the second initial speed S2INof the second chain link cluster C2 is known, deviating speed values at a later timemay indicate potential issues with the conveyor chain 1 or the drive unit used for driving the conveyor chain 1. Other alternative embodiments are exemplified in figures 6a-b, where the conveyor chain 1 comprises a first chain link cluster C1 formed by a plurality of connectedcluster chain links 2CL following directly after each other, and a second chain linkcluster C2 formed by a plurality of connected cluster chain links 2CLfollowing directly after each other. In figure 6a, the first chain link cluster C1 comprises five cluster chain links 2CLfollowing directly after each other, and the second chain link cluster C2 comprises five cluster chain links 2CLfollowing directly after each other. The first chain link cluster C1 and the second chain link cluster C2 are separated from each other along theconveyor chain 1. The first chain link cluster C1 comprises three detection elements5 and the second chain link cluster C2 comprises three detection elements 5. Each detectable chain link 2D comprises a detection element 5, as described above. Thefirst chain link cluster C1 comprises three detectable chain links 2D separated by non-detectable chain links 2ND, where one non-detectable chain link 2ND is positionedbetween two detectable chain links 2D. The second chain link cluster C2 comprisesthree detectable chain links 2D separated by non-detectable chain links 2ND, whereone non-detectable chain link 2ND is positioned between two detectable chain links 2D.With this construction of the conveyor chain 1, consecutive pairs of the two detectablechain links 2D in the first chain link cluster C1 are separated by one non-detectablechain link 2ND, and consecutive pairs of the two detectable chain links 2D in the secondchain link cluster C2 are separated by one non-detectable chain link 2ND.With the arrangement of the conveyor chain 1 shown in figure 6a, one of the detection elements 5 of the first chain link cluster C1 and one corresponding detection element 5 of the second chain link cluster C2 could be used for determining the deviatingcondition CD, as described above by determining the first time offset TO1 and thesecond time offset TO2. In this embodiment, the first sensor unit 4a may be configuredfor detecting an initial passage PIand a following passage PFOof the leading detectionelement 5 of the first chain link cluster C1, and the second sensor unit 4b may beconfigured for detecting an initial passage PIand a following passage PFOof theleading detection element 5b of the second chain link cluster C2. These detectionsmay be used for determining the deviating condition CD. At the initial time TIN, theconveyor system is suitably configured such that the first sensor unit 4a and thesecond sensor unit 4b are arranged in positions relative to the conveyor chain 1, such that simultaneously the leading detection element 5 of the first chain link cluster C1 is adjacent to the first sensor unit 4a and the leading detection element 5 of the second chain link cluster C2 is adjacent to the second sensor unit 4b. In this way, whenoperating the conveyor system S at the initial time TIN, the first sensor unit 4a maydetect an initial passage PI of the leading detection element 5 of the first chain linkcluster C1 and the second sensor unit 4b may detect an initial passage PI of theleading detection element 5 of the second chain link cluster C2 simultaneously, or almost simultaneously. In this exemplified embodiment, the leading detection element 5 of the first chain link cluster C1 may be denoted a first detection element, and the leading detection element 5 of the second chain link cluster C2 may be denoted a second detection element, to correspond to the designations of the detectable chain links in the embodiment described in connection to figures 4a-b. In the embodiment shown in figure 6a, the first sensor unit 4a could further be configured for detecting a passage of the intermediate detection element 5 and the trailing detection element 5 of the first chain link cluster C1. The second sensor unit 4b could further be configured for detecting a passage of the intermediate detection element 5 and the trailing detection element 5 of the second chain link cluster C2.Thus, the first sensor unit 4a may be arranged to detect the three detectable chainlinks 2D in the first chain link cluster C1, and the second sensor unit 4b may bearranged to detect the three detectable chain links 2D in the second chain link clusterC2. Based on the detection of three detectable chain links 2D in the first chain linkcluster C1 by the first sensor unit 4a, a more precise determination of the first speedS1 can be achieved. Based on the detection of three detectable chain links 2D in thesecond chain link cluster C2 by the second sensor unit 4b, a more precisedetermination of the second speed S2 of the second chain link cluster C2 can beachieved. The respective speeds can be calculated by detecting the passage time TP between the sensor unit detections of the detection elements 5 in the respective chain link clusters when the distances between the detection elements are known. When the first initial speed S1INof the first chain link cluster C1 is known and the secondinitial speed S2IN of the second chain link cluster C2 is known, deviating speed valuesat a later time may indicate potential issues with the conveyor chain 1 or the drive unit used for driving the conveyor chain 1. In figure 6b, the first chain link cluster C1 comprises seven cluster chain links 2CLfollowing directly after each other, and the second chain link cluster C2 comprises seven cluster chain links 2CLfollowing directly after each other. The first chain link cluster C1 and the second chain link cluster C2 are separated from each other alongthe conveyor chain 1. The first chain link cluster C1 comprises three detectionelements 5 and the second chain link cluster C2 comprises three detection elements 5. The first chain link cluster C1 comprises three detectable chain links 2Dseparated by non-detectable chain links 2ND, where two non-detectable chain links 2NDare positioned between two detectable chain links 2D. Each detectable chain link 2Dcomprises a detection element 5, as described above. The second chain link cluster C2 comprises three detectable chain links 2Dseparated by non-detectable chain links 2ND, where two non-detectable chain links 2ND are positioned between two detectablechain links 2D. With this construction of the conveyor chain 1, consecutive pairs of thetwo detectable chain links 2D in the first chain link cluster C1 are separated by two non-detectable chain links 2ND, and consecutive pairs of the two detectable chain links 2D in the second chain link cluster C2 are separated by two non-detectable chain link 2ND. With the arrangement of the conveyor chain 1 shown in figure 6b, one of the detection elements 5 of the first chain link cluster C1 and one corresponding detection element 5 of the second chain link cluster C2 could be used for determining the deviatingcondition CD, as described above by determining the first time offset TO1 and thesecond time offset TO2. In this embodiment, the first sensor unit 4a may be configured for detecting an initial passage PI and a following passage PFO of the leading detectionelement 5 of the first chain link cluster C1, and the second sensor unit 4b may beconfigured for detecting an initial passage PI and a following passage PFO of the leading detection element 5b of the second chain link cluster C2. These detectionsmay be used for determining the deviating condition CD. At the initial time TIN, theconveyor system is suitably configured such that the first sensor unit 4a and the second sensor unit 4b are arranged in positions relative to the conveyor chain 1, such that simultaneously the leading detection element 5 of the first chain link cluster C1 is adjacent to the first sensor unit 4a and the leading detection element 5 of the second chain link cluster C2 is adjacent to the second sensor unit 4b. In this way, whenoperating the conveyor system S at the initial time TIN, the first sensor unit 4a maydetect an initial passage PIof the leading detection element 5 of the first chain link cluster C1 and the second sensor unit 4b may detect an initial passage PIof the leading detection element 5 of the second chain link cluster C2 simultaneously, or almost simultaneously. In this exemplified embodiment, the leading detection element 5 of the first chain link cluster C1 may be denoted a first detection element, and the leading detection element 5 of the second chain link cluster C2 may be denoted a second detection element, to correspond to the designations of the detectable chain links in the embodiment described in connection to figures 4a-b. In the embodiment shown in figure 6b, the first sensor unit 4a could further be configured for detecting a passage of the intermediate detection element 5 and the trailing detection element 5 of the first chain link cluster C1. The second sensor unit 4b could further be configured for detecting a passage of the intermediate detection element 5 and the trailing detection element 5 of the second chain link cluster C2. Thus, the first sensor unit 4a may be arranged to detect the three detectable chain links 2D in the first chain link cluster C1, and the second sensor unit 4b may bearranged to detect the three detectable chain links 2D in the second chain link clusterC2. Based on the detection of three detectable chain links 2D with greater separation in the first chain link cluster C1 by the first sensor unit 4a, a more precise determination of the first speed S1 can be achieved. Based on the detection of three detectable chain links 2D with greater separation in the second chain link cluster C2 by the second sensor unit 4b, a more precise determination of the second speed S2 of the second chain link cluster C2 can be achieved. The respective speeds can be calculated by detecting the passage time TP between the sensor unit detections of the detection elements 5 in the respective chain link clusters when the distances between the detection elements are known. When the first initial speed S1IN of the first chain link cluster C1 is known and the second initial speed S2IN of the second chain link cluster C2 are known, deviating speed values at a later time may indicate potential issues with the conveyor chain 1 or the drive unit used for driving the conveyor chain 1. It should be understood that the chain link clusters may comprise any suitable number of detectable chain links 2Dand non-detectable chain links 2ND. In the examplesabove, the leading detection elements 5 in the respective clusters are used fordetermining the deviating condition CD, but any suitable detection elements 5 in the respective chain link clusters may be used for determining the deviating condition CD. Further, two or more corresponding pairs of detection elements is different chain link clusters may, based on the principle described above, be used for determining the deviation condition CD. In further alternative embodiments, the conveyor chain 1 comprises one or more further chain link clusters CF formed by a plurality of connected cluster chain links 2CLfollowing directly after each other. The one or more of the cluster chain links 2CLof the one or more further chain link clusters CF are arranged as detectable chain links 2Deach comprising a detection element 5, and the first sensor unit 4a and / or the second sensor unit 4b are then configured for detecting the detectable chain links 2Dof the one or more further chain link clusters CF. In the embodiment illustrated in figure 7, the conveyor chain 1 comprises a first chain link cluster C1, a second chain link cluster C2, and a further chain link cluster CF.Each chain link cluster is in this embodiment formed by three connected cluster chainlinks 2CL following directly after each other, and all cluster chain links 2CL are arranged as detectable chain links 2D each comprising a detection element 5. The determination of the deviating condition CD may be similar to the determinations described in the embodiments above by detecting the first chain link cluster C1 and the second chain link cluster C2. In this exemplified embodiment, any suitable detection element 5 of the first chain link cluster C1 may be denoted a first detection element, and any suitable detection element 5 of the second chain link cluster C2 may be denoted a second detection element, to correspond to the designations of the detectable chain links in the embodiment described in connection to figures 4a-b. However, if arranging the further chain link cluster CF at a suitable distance from the first chain link cluster C1, also the first chain link cluster C1 and the further chain link cluster CF may be used for determining the deviating condition CD. Then, the first sensor unit 4a may be used for detecting the detection elements 2 of the further chain link cluster CF, and the second sensor unit 4b may be used for detecting the detection elements 2 of the first chain link cluster C1. With this configuration, any suitable detection element 5 of the further chain link cluster CF may be denoted a first detection element, and any suitable detection element 5 of the first chain link cluster C1 may be denoted a second detection element, to correspond to the designations of the detectable chain links in the embodiment described in connection to figures 4a-b. Similarly, if arranging the further chain link cluster CF at a suitable distance from the second chain link cluster C2, also the second chain link cluster C2 and the further chain link cluster CF may be used for determining the deviating condition CD. Then, the first sensor unit 4a may be used for detecting the detection elements 2 of the second chain link cluster C2, and the second sensor unit 4b may be used for detecting the detection elements 2 of the further chain link cluster CF. Speeds may bedetermined as described in the embodiments above. With this configuration, anysuitable detection element 5 of the second chain link cluster C2 may be denoted a first detection element, and any suitable detection element 5 of the further chain link cluster CF may be denoted a second detection element, to correspond to the designations of the detectable chain links in the embodiment described in connection to figures 4a-b. For all embodiments, the deviating condition CD is determined by the same principle.First, an initial passage PI of a first detection element 5a is detected by the first sensorunit 4a and an initial passage PI of a second detection element 5b is detected by thesecond sensor unit 4b at an initial time TIN. Thereafter, a following passage PFO of the first detection element 5a is detected by the first sensor unit 4a and a following passage PFO of the second detection element 5b is detected by the second sensorunit 4b at a detection time TD after the initial time TIN. A first time offset TO1 betweenthe initial passage PI of the first detection element 5a and the initial passage PI of thesecond detection element 5b is determined, and a second time offset TO2 between the following passage PFO of the first detection element 5a and the following passagePFO of the second detection element 5b is determined. A difference between the firsttime offset TO1 and the second time offset TO2 is indicative of a deviating condition CD of the conveyor chain 1. The present disclosure has been presented above with reference to specific embodiments. However, other embodiments than the above described are possible and within the scope of the disclosure. Different method steps than those described above, performing the method by hardware or software, may be provided within the scope of the disclosure. Thus, according to an exemplary embodiment, there is provided a non-transitory computer-readable storage medium storing one or more programs configured to be executed by one or more processors of the conveyorsystem S with the control unit 7, the one or more programs comprising instructions forperforming the method according to any one of the above-discussed embodiments. Alternatively, according to another exemplary embodiment a cloud computing system can be configured to perform any of the method aspects presented herein. The cloud computing system may comprise distributed cloud computing resources that jointly perform the method aspects presented herein under control of one or more computer program products. Moreover, the processor may be connected to one or more communication interfaces and / or sensor interfaces for receiving and / transmitting data with external entities such as e.g. sensors, an off-site server, or a cloud-based server.The processor or processors associated with the conveyor system S may be orinclude any number of hardware components for conducting data or signal processing or for executing computer code stored in memory. The system may have an associated memory, and the memory may be one or more devices for storing data and / or computer code for completing or facilitating the various methods described in the present description. The memory may include volatile memory or non-volatile memory. The memory may include database components, object code components, script components, or any other type of information structure for supporting the various activities of the present description. According to an exemplary embodiment, any distributed or local memory device may be utilized with the systems and methods of this description. According to an exemplary embodiment the memory is communicably connected to the processor (e.g., via a circuit or any other wired, wireless, or network connection) and includes computer code for executing one or more processes described herein. It will be appreciated that the above description is merely exemplary in nature and is not intended to limit the present disclosure, its application or uses. While specific examples have been described in the specification and illustrated in the drawings, it will be understood by those of ordinary skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure as defined in the claims. Furthermore, modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular examples illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out the teachings of the present disclosure, but that the scope of the present disclosure will include any embodiments falling within the foregoing description and the appended claims. Reference signs mentioned in the claims should not be seen as limiting the extent of the matter protected by the claims, and their sole function is to make claims easier to understand.

[0002] REFERENCE SIGNS1: Conveyor chain2: Chain link2CL: Cluster chain link2D: Detectable chain link2ND: Non-detectable chain link3: Support structure4a: First sensor unit4b: Second sensor unit5: Detection element5a: First detection element5b: Second detection element6: Drive shaft7: Control unitC1: First chain link clusterC2: Second chain link clusterCD: Deviating conditionD1: First separation distanceD2: Second separation distanceDT: Transporting directionLIN: Initial lengthPFO: Following passagePI: Initial passagePIN: Initial pitchS: Conveyor systemS1: First speedS1IN: Initial first speedS2: Second speedS2IN: Initial second speedSL: Lower sideSU: Upper sideTD: Detection timeTIN: Initial timeTO1: First time offsetTO2: Second time offsetTP: Passage time

Claims

CLAIMS1. A method for monitoring a conveyor system (S) comprising a conveyor chain (1)with a plurality of connected chain links (2) and a support structure (3) arranged for supporting the conveyor chain (1), wherein the conveyor chain (1) is arranged as an endless conveyor chain structure configured for moving relative to thesupport structure (3) in a transporting direction (DT), wherein the conveyor chain (1) comprises a first detection element (5a) and a second detection element (5b), wherein the first detection element (5a) and the second detection element (5b) are separated from each other along the conveyor chain (1), wherein the conveyor system (S) comprises a first sensor unit (4a) and a second sensor unit (4b) arranged in positions relative to the conveyor chain (1) where simultaneously the first detection element (5a) is adjacent to the first sensor unit (4a) and the second detection element (5b) is adjacent to the secondsensor unit (4b), wherein the method comprises the steps: detecting an initial passage (PI) of the first detection element (5a) by the first sensor unit (4a) and an initial passage (PI) of the second detection element (5b) by the second sensor unit (4b) at an initial time (TIN); detecting a following passage (PFO) of the first detection element (5a) by the first sensor unit (4a) and a following passage (PFO) of the second detection element (5b) by the second sensor unit (4b) at a detection time (TD) after the initial time (TIN); determining a first time offset (TO1) between the initial passage (PI) of the first detection element (5a) and the initial passage (PI) of the second detection element (5b), and determining a second time offset (TO2) between the following passage (PFO) of the first detection element (5a) and the following passage (PFO) of the second detection element (5b), wherein a difference between the first time offset (TO1) and the second time offset (TO2) is indicative of a deviating condition (CD) of the conveyor chain (1).

2. The method according to claim 1,wherein the conveyor chain (1) comprises a first chain link cluster (C1) formed by a plurality of connected cluster chain links (2CL) following directly after each other, and a second chain link cluster (C2) formed by a plurality ofconnected cluster chain links (2CL) following directly after each other, wherein the first chain link cluster (C1) and the second chain link cluster (C2) are separated from each other along the conveyor chain (1), wherein the first chain link cluster (C1) comprises the first detection element (5a) and the second chain link cluster (C2) comprises the second detection element (5b).

3. The method according to claim 2,wherein one or more of the cluster chain links (2CL) of the first chain link cluster (C1) are arranged as detectable chain links (2D) each comprising a detection element (5), wherein one or more of the cluster chain links (2CL) of the second chain link cluster (C2) are arranged as detectable chain links (2D) each comprising a detection element (5), wherein the method further comprises the steps: detecting the detectable chain links (2D) of the first chain link cluster (C1) by the first sensor unit (4a); and detecting the detectable chain links (2D) of the second chain link cluster (C2) by the second sensor unit (4b).

4. The method according to claim 3,wherein the first chain link cluster (C1) comprises two or more detectable chain links (2D), and / or the second chain link cluster (C2) comprises two or more detectable chain links (2D).

5. The method according to claim 4,wherein consecutive pairs of the two or more detectable chain links (2D) of the first chain link cluster (C1) are separated by one or more non-detectable chain links (2ND); and / or wherein consecutive pairs of the two or more detectable chain links (2D) of the second chain link cluster (C2) are separated by one or more non-detectable chain links (2ND).

6. The method according to claim 4 or 5,wherein the method further comprises the steps: detecting at least two of the two or more detectable chain links (2D) in the first chain link cluster (C1) by the first sensor unit (4a) and based on the detection determining a first speed (S1) of the first chain link cluster (C1); and / or detecting at least two of the two or more detectable chain links (2D) in the second chain link cluster (C2) by thesecond sensor unit (4b) and based on the detection determining a second speed (S2) of the second chain link cluster (C2).

7. The method according to claim 6,wherein the conveyor chain (1) is configured with an initial pitch (PIN) at the initial time (TIN), wherein the method further comprises the steps: measuring a passage time (TP) between passages of the detected at least two of the two or more detectable chain links (2D) in the first chain link cluster (C1) at the initial time (TIN), and determining an initial first speed (S1IN) of the first chain link cluster (C1) based on the measured passage time (TP) and the initial pitch (PIN); and / or measuring a passage time (TP) between passages of the detected at least two of the two or more detectable chain links (2D) in the second chain link cluster (C2) at the initial time (TIN), and determining an initial second speed (S2IN) of the second chain link cluster (C2) based on the measured passage time (TP) and the initial pitch (PIN).

8. The method according to any of claims 2 to 7,wherein the conveyor chain (1) comprises one or more further chain link clusters (CF) formed by a plurality of connected cluster chain links (2CL) following directly after each other, wherein one or more of the cluster chain links (2CL) of the one or more further chain link clusters (CF) are arranged as detectable chain links (2D) each comprising a detection element (5), wherein the method further comprises the step: detecting the detectable chain links (2D) of the one or more further chain link clusters (CF) by the first sensor unit (4a) and / or the second sensor unit (4b).

9. The method according to any preceding claim,wherein the deviating condition (CD) of the conveyor chain (1) is an extension of the conveyor chain (1) from an initial length (LIN).

10. A conveyor system (S) comprising a conveyor chain (1) with a plurality ofconnected chain links (2) and a support structure (3) arranged for supporting the conveyor chain (1), wherein the conveyor chain (1) is arranged as an endlessconveyor chain structure configured for moving relative to the support structure (3) in a transporting direction (DT), wherein the conveyor chain (1) comprises a first detection element (5a) and a second detection element (5b), wherein the first detection element (5a) and the second detection element (5b) are separated from each other along the conveyor chain (1), wherein the conveyor system (S) comprises a first sensor unit (4a) and a second sensor unit (4b) arranged in positions relative to the conveyor chain (1) where simultaneously the first detection element (5a) is adjacent to the first sensor unit (4a) and the second detection element (5b) is adjacent to the second sensor unit (4b),wherein the first sensor unit (4a) is configured for detecting an initial passage (PI) of the first detection element (5a) at an initial time (TIN) and the second sensor unit (4b) is configured for detecting an initial passage (PI) of the second detection element (5b) at the initial time (TIN); wherein the first sensor unit (4a) is configured for detecting a following passage (PFO) of the first detection element (5a) at a detection time (TD) after the initial time (TIN) and the second sensor unit (4b) is configured for detecting a following passage (PFO) of the second detection element (5b) at the detection time (TD) after the initial time (TIN); wherein the conveyor system (S) is configured for determining a first time offset (TO1) between the initial passage (PI) of the first detection element (5a) and the initial passage (PI) of the second detection element (5b), and determining a second time offset (TO2) between the following passage (PFO) of the first detection element (5a) and the following passage (PFO) of the second detection element (5b), wherein a difference between the first time offset (TO1) and the second time offset (TO2) is indicative of a deviating condition (CD) of the conveyor chain (1).

11. The conveyor system (S) according to claim 10,wherein the first detection element (5a) and the second detection element (5b) are arranged at a distance from each other along the conveyor chain (1) corresponding to a distance between the first sensor unit (4a) and the second sensor unit (4b).

12. The conveyor system (S) according to claim 10 or 11,wherein the first detection element (5a) and the second detection element (5b) are separated from each other along the conveyor chain (1) by a first separation distance (D1) formed by a plurality of chain links (2) following directly after each other and a second separation distance (D2) formed by a plurality of chain links (2) following directly after each other.

13. The conveyor system (S) according to claim 12,wherein the first separation distance (D1) is extending in the transporting direction (DT) from the first detection element (5a) to the second detection element (5b), wherein the second separation distance (D2) is extending in the transporting direction (DT) from the second detection element (5b) to the first detection element (5a).

14. The conveyor system (S) according to any of claims 10 to 13,wherein the conveyor chain (1) comprises a first chain link cluster (C1) formed by a plurality of connected cluster chain links (2CL) following directly after each other, and a second chain link cluster (C2) formed by a plurality of connected cluster chain links (2CL) following directly after each other, wherein the first chain link cluster (C1) and the second chain link cluster (C2) are separated from each other along the conveyor chain (1), wherein the first chain link cluster (C1) comprises the first detection element (5a) and the second chain link cluster (C2) comprises the second detection element (5b).

15. The conveyor system (S) according to claim 14,wherein one or more of the cluster chain links (2CL) of the first chain link cluster (C1) are arranged as detectable chain links (2D) each comprising a detection element (5), wherein one or more of the cluster chain links (2CL) of the second chain link cluster (C2) are arranged as detectable chain links (2D) each comprising a detection element (5), wherein the first sensor unit (4a) is configured for detecting the detectable chain links (2D) of the first chain link cluster (C1) and the second sensor unit (4b) is configured for detecting the detectable chain links (2D) of the second chain link cluster (C2).

16. The conveyor system (S) according to claim 15,wherein the first chain link cluster (C1) comprises two or more detectable chain links (2D), and / or wherein the second chain link cluster (C2) comprises two or more detectable chain links (2D).

17. The conveyor system (S) according to claim 16,wherein consecutive pairs of the two or more detectable chain links (2D) in the first chain link cluster (C1) are separated by one or more non-detectable chain links (2ND), and / or wherein consecutive pairs of the two or more detectable chain links (2D) in the second chain link cluster (C2) are separated by one or more non-detectable chain links (2ND).

18. The conveyor system (S) according to any of claims 16 or 17,wherein the first sensor unit (4a) is configured for detecting at least two of the two or more detectable chain links (2D) in the first chain link cluster (C1) and based on the detection determining a first speed (S1) of the first chain link cluster (C1), and / or wherein the second sensor unit (4b) is configured for detecting at least two of the two or more detectable chain links (2D) in the second chain link cluster (C2) and based on the detection determining a second speed (S2) of the second chain link cluster (C2).

19. The conveyor system (S) according to any of claims 13 to 18,wherein the conveyor chain (1) comprises one or more further chain link clusters (CF) formed by a plurality of connected cluster chain links (2CL) following directly after each other, wherein one or more of the cluster chain links (2CL) of the one or more further chain link clusters (CF) are arranged as detectable chain links (2D) each comprising a detection element (5), wherein the first sensor unit (4a) and / or the second sensor unit (4b) are configured for detecting the detectable chain links (2D) of the one or more further chain link clusters (CF).

20. The conveyor system (S) according to any of claims 10 to 19,wherein the first sensor unit (4a) and second sensor unit (4b) are attached to the support structure (3).

21. The conveyor system (S) according to any of claims 10 to 20,wherein the conveyor chain (1) is configured with an initial pitch (PIN) at the initial time (TIN).

22. The conveyor system (S) according to any of claims 10 to 21,wherein the deviating condition (CD) of the conveyor chain (1) is an extension of the conveyor chain (1) from an initial length (LIN).

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