Object handling system, industrial facility comprising an object handling system, method for maintaining an object handling system and method for assembling an object handling system

Abstract

An object handling system (100) for handling objects (111) transported by a conveyor belt (110) in a transportation direction (T) comprises an inspection unit assembly (120) of one inspection units (121, 122) and a frame (160) arranged across the conveyor belt. The frame comprises a maintenance bridge (161), extending across a width of the conveyor belt. The inspection unit assembly is positioned above the conveyor belt and rotatably attached to the frame by an inspection unit connector (140). The inspection unit connector is configured to allow a rotation of the inspection unit assembly around an axis of rotation. Thereby an inspection opening (123) of the inspection units are rotatable from an inspection operation position facing the conveyor belt to a first maintenance position facing a space above the maintenance bridge. An industrial facility, a method for maintaining and a method for assembling an object handling system is also disclosed.

Description

[0001] OBJECT HANDLING SYSTEM,

[0002] INDUSTRIAL FACILITY COMPRISING AN OBJECT HANDLING SYSTEM,

[0003] METHOD FOR MAINTAINING AN OBJECT HANDLING SYSTEM AND METHOD FOR ASSEMBLING AN OBJECT HANDLING SYSTEM

[0004] TECHNICAL FIELD

[0005] The present technology refers in general to methods and devices in connection with object transporting and in particular to methods and devices handling objects transported on a conveyor belt.

[0006] BACKGROUND

[0007] In many types of industry of today, large volumes of different kinds of material are handled in an automated or semi-automated manner, including internal transports of different kinds. In many technical applications, objects of various kinds are therefore transported on conveyor belts. Objects may for instance be transported from one process station to another during production, or other types of object treatments. During such a transportation, different object handling actions are often performed, such as object analysis and / or object sorting. Typically, the objects are transported on a conveyor belt and different kinds of handling equipment is arranged close to the conveyor belt. Such handling equipment may be different kinds of inspection, analysis or sorting equipment.

[0008] Regardless of the type of objects to be transported, such automated systems are typically built as heavy-duty facilities capable of processing very large amounts of objects or materials, to increase the cost benefits. The material in such industrial plants may e.g. be bulk material or larger quantities of smaller objects. Thousands and thousands of kilos of material or objects may be processed each day, which calls for equipment that will manage extensive wear and contamination. The industrial arrangements therefore have to be constructed with the focus on robustness and heavy wear resistance. This typically results in industrial facilities where the different treatment or handling stations are put into place once in for all e.g. by means of large overhead cranes. Maintenance or replacements of parts of such facilities often requires that the entire facility is closed down and dismounted to some degree.

[0009] One typical example of such industrial facility systems is industrial sorting of waste material. Inspection units are provided to identify each object of the huge amount of transported objects and sorting arrangements may be controlled depending on the type of the identified object. Such industrial systems are typically involving large amounts of transported objects, which inevitably introduce large amounts of contamination that successively may deteriorate the operation of the different handling equipment. Closing down the entire, or at least a significant part of, the facility and dismounting parts thereof by means of e.g. overhead cranes causes large economic losses and poses non-negligible risks for injuries. There is therefore a need for frequent maintenance work at the handling equipment, such as cleaning and / or replacing wear- and-tear parts that can be performed in a quick and non-hazardous way.

[0010] Since most of the heavy handling equipment is provided above or at least in the vicinity of the conveyor belts, maintenance needs often call for operators to climb on to the conveyor belts to reach the handling equipment, and possibly also crawl below the handling equipment. Such work requires sophisticated safety precautions to prevent high risks for injuries or involves inadequate working positions.

[0011] In the published Japanese patent application JP 2011 -122837 A, a color-sorting machine for handling objects transported by a conveyor is disclosed. The color-sorting machine comprises an inspection unit assembly being arranged across the conveyor by a frame. The inspection unit assembly is rotatably attached for enabling maintenance.

[0012] SUMMARY

[0013] A general object of the present technology is to improve the maintenance possibilities for equipment used in connection with object transport on conveyor belts. The above object is achieved by methods and devices according to the independent claims. Preferred embodiments are defined in dependent claims.

[0014] In general words, in a first aspect, an object handling system for handling objects transported by a conveyor belt in a transportation direction comprises an inspection unit assembly and a frame. The inspection unit assembly comprises at least one inspection unit connected by a structural member. The inspection unit or each of the inspection units has a respective inspection opening. The frame is configured for being arranged across the conveyor belt. The frame comprises a maintenance bridge, extending across a width of the conveyor belt. The maintenance bridge is configured to support a weight of a human operator. The inspection unit assembly is positioned above the conveyor belt and rotatably attached to the frame by an inspection unit connector. The inspection unit connector is configured to allow a rotation of the inspection unit assembly around an axis of rotation. Thereby the inspection opening of the inspection units are rotatable from an inspection operation position facing the conveyor belt to a first maintenance position facing a space above the maintenance bridge.

[0015] In a third aspect, an industrial facility for processing large amounts of material or objects comprises a conveyor belt and an object handling system according to the first aspect arranged across the conveyor belt.

[0016] In a third aspect, a method for maintaining an object handling system according to the first aspect comprises rotating of the inspection unit assembly to the first maintenance position. Maintenance to the interior of the inspection unit is performed via the inspection opening. The inspection unit assembly is then rotated back to the inspection operation position.

[0017] In a fourth aspect, a method for assembling an object handling system according to the first aspect comprises providing the frame across the conveyor belt. A sorting unit assembly with sorting units is assembled, resting on the conveyor belt. A sorting unit connector is attached the to the frame. The sorting units are moved to the sorting operation position by use of the sorting unit connector. The maintenance bridge is mounted to the frame. A structural member of the inspection unit assembly is mounted to the inspection unit connector. The inspection units are finally assembled into the structural member.

[0018] One advantage with the proposed technology is that maintenance of the object handling system is easy and safely performed. Other advantages will be appreciated when reading the detailed description.

[0019] BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The invention, together with further objects and advantages thereof, may best be understood by making reference to the following description taken together with the accompanying drawings, in which:

[0021] FIG. 1 is a schematic drawing of an embodiment of an object handling system with inspection units in an inspection operation position;

[0022] FIG. 2 is a schematic drawing of an embodiment of an object handling system with inspection units in a first maintenance position and with a sorting unit assembly in a third maintenance position;

[0023] FIG. 3 is a schematic drawing of an embodiment of an object handling system with inspection units in a second maintenance position;

[0024] FIG. 4 is a flow diagram of steps of an embodiment of a method for maintaining an object handling system;

[0025] FIG. 5 is a schematic drawing of another embodiment of an object handling system in an initial assembling stage;

[0026] FIG. 6 is a schematic drawing of the other embodiment of an object handling system in a subsequent assembling stage;

[0027] FIG. 7 is a schematic drawing of the other embodiment of an object handling system in a further subsequent assembling stage;

[0028] FIG. 8 is a schematic drawing of the other embodiment of an object handling system in a final assembling stage;

[0029] FIGS. 9A-B illustrate a sliding mechanism of an embodiment of a method of an object handling system; and

[0030] FIG. 10 is a flow diagram of steps of an embodiment of a method for assembling an object handling system. DETAILED DESCRIPTION

[0031] Throughout the drawings, the same reference numbers are used for similar or corresponding elements.

[0032] When maintaining or assembling equipment surrounding a conveyor belt, and in particular in heavy-duty industrial plants, risks for injuries are requested to be minimized. Surrounding equipment is typically heavy, and upon assembling or servicing such equipment, heavy lifting operations may have to be performed. Having, as in prior art, only a conveyor belt as a closest supporting surface, not always being stable enough for standing on, such work may be hazardous. Heavy lifting operations and awkward working positions are often encountered and overhead cranes may have to be used, calling for additional precautions concerning safety. Any provision of stable surface between the different equipment stations and the conveyor belt is not easily provided, since operation of the equipment requires direct view onto the conveyor belt and often with a very small distance therebetween.

[0033] Instead, a principle of providing a stable surface for an operator at the side of the equipment to be handled is adopted, together with solutions for displacing, moving or rotating the equipment of which maintenance is requested so that they easily can be reached from the side.

[0034] Figure 1 illustrates schematically an embodiment of an object handling system 100 for handling objects 111 transported by a conveyor belt 110 in a transportation direction T. In a typical case, the width of the conveyor belt may range from a few decimeters to several meters, depending on the application. The object handling system may e.g. be a sorting system or an object analyzing system. An inspection unit assembly 120 comprises at least one inspection unit 121 , 122 connected by a structural member 128. For large systems, several inspection units 121 , 122 are usually used, in order to cover the entire width of the conveyor belt. In such systems, preferably, the inspection unit assembly 120 comprises at least two inspection units 121 , 122. In the present illustration, there are four inspection units 121 , 122. Each of the inspection units 121 , 122 has a respective inspection opening 123. In the present illustration, the inspection units 121 , 122 are turned with the inspection openings 123 facing downwards towards the conveyor belt 110. In other words, the inspection units 121 , 122 are positioned in an inspection operation position facing the conveyor belt 110. When the conveyor belt 110 is driven, objects 111 will pass in front of the inspection openings 123 and may be inspected by the inspection units 121 , 122.

[0035] The inspection units 121 , 122 may be of different kinds. Non-exclusive examples are that they may measure e.g. size and / or color and / or texture and / or type or it can analyze chemical content or different kinds of responses to applications of different fields, such as electrical fields, magnetic fields or e.g. electromagnetic radiation. In a sorting system, the inspection units 121 , 122 typically analyze the chemical composition of the objects 111 at the conveyor belt 110. Common for such inspection units and in particular for inspection units used in industrial facilities for processing large amounts of material or objects and with large conveyor belts, is that they are usually heavy pieces of equipment.

[0036] A frame 160 is configured for being arranged across the conveyor belt 110. The frame 160 thus extends from one side over at least a major part of the conveyor belt 110 in a direction transverse to the transport direction. The frame 160 comprises a maintenance bridge 161 , extending across a width of the conveyor belt 110. The maintenance bridge 161 is configured to support a weight of a human operator and to fulfil all necessary safety requirements. In such a way, a position located above the conveyor belt 110 is provided, which is safe for a human operator to be in. Standing on the maintenance bridge 161 will exclude risks of being supported by a non-rigid conveyor belt 110 and it will also ensure that the operator is safe if the conveyor belt 110 by mistake is operated during maintenance work. The maintenance bridge 161 has preferably a width, in the transportation direction T, that allows a maintenance operator to move easily on the maintenance bridge 161 . Widths of at least 50 cm are preferred. The length of the maintenance bridge 161 , i.e. the dimension perpendicular to the transportation direction T, is preferably at least equal to the width of the conveyor belt 110. The length of the bridge 161 is therefore typically from a few decimeters up to several meters, depending on the application, the conveyor belt width and the available space around the conveyor belt 110. The inspection unit assembly 120 is, as mentioned above, positioned above the conveyor belt 110. The inspection unit assembly 120 is rotatably attached to the frame

[0037] 160 by an inspection unit connector 140. The inspection unit connector 140 is configured to allow a rotation of the inspection unit assembly 120 around an axis of rotation X. Thereby, the inspection opening 123 of the inspection units 121 , 122 are rotatable from an inspection operation position facing the conveyor belt 110 to other positions.

[0038] The object handling system 100 is typically a part of an industrial facility for processing large amounts of material or objects. The industrial facility thereby comprises at least one conveyor belt 110. The object handling system 100 is thereby arranged across the conveyor belt 110.

[0039] Figure 2 illustrates schematically the same embodiment as in Figure 1 , when the inspection unit assembly 120 has been rotated. In this particular illustration, the inspection unit assembly 120 has been rotated so that the inspection opening 123 of the inspection units 121 , 122 are moved to a first maintenance position facing a space above the maintenance bridge 161. A maintenance operator therefore has an easy access to the inspection opening 123 without having to climb onto the conveyor belt 110. Furthermore, the maintenance operator may service the inspection opening 123 in an ergonomically advantageous position.

[0040] The inspection opening 123 comprises in the present embodiment an optical window 126. The first maintenance position facing the space above the maintenance bridge

[0041] 161 thereby enables cleaning of the optical window 126 in an easy manner.

[0042] Returning to the embodiment of Figure 1 , each of the inspection units 121 , 122 has one or more interior-access openings 124. These interior-access openings 124 provide access into the interior of the respective inspection unit 121 , 122. A lid 125 is typically covering the interior-access opening 124 in order to prohibit unnecessary contamination. Preferably, the inspection unit connector 140 is configured such that the internal-access opening 124 of the inspection units 121 , 122 are rotatable to a second maintenance position facing a space above the maintenance bridge 161 . Such a situation is illustrated in Figure 3. In figure 3, it is seen that an operator being situated at the maintenance bridge 161 has an easy access also to the interior-access opening 124. The second maintenance position facing a space above the maintenance bridge 161 thereby enables easy replacement of wear and tear parts, e.g. illumination means.

[0043] There are thus two or three positions that are advantageous for performing either an operation of the inspection units 121 , 122 or maintenance of the inspection units 121 , 122. In a preferred embodiment, it is therefore provided for means that assists in finding and maintaining the inspection unit assembly 120 in the requested positions. To this end, the inspection unit connector 140 comprises a latch configured to releasably fixate the inspection unit assembly 120 in the inspection operation position and in the first maintenance position. If also maintenance of the interior of the inspection units 121 , 122 is requested, it is preferred if the latch is configured to releasably fixate the inspection unit assembly 120 also in the second maintenance position. The latch might be released or controlled electrically.

[0044] In one embodiment, the inspection unit assembly 120 may further comprise a control unit. Preferably, the control unit comprises at least one inspection unit lock sensor configured for determining whether the inspection unit assembly 120 is locked into the inspection operation position. In other words, the lock sensor checks if the latch fixating the inspection unit assembly 120 in the inspection operation position is correctly positioned for fixating the inspection unit assembly 120. The control unit is then configured for providing an output signal representing such a lock status.

[0045] The industrial facility in which the object handling system 100 is comprised may comprises a supervising control. This supervising control is preferably configured for communicating with the control unit of the inspection unit assembly 120. Thereby, the industrial facility may obtain information about a lock status of the inspection unit assembly 120.

[0046] The inspection units 121 , 122 may be, as mentioned above, relatively large and heavy. Even a rotation of the inspection unit assembly 120, where the main weight is carried by the rotating means, may therefore be relatively heavy. It is a request that the forces that the maintenance personnel have to apply onto the parts of the system is restricted and that the loads from the system parts on the maintenance personnel also is kept low and at least below standard safety regulation restrictions. In order to minimize or at least reduce the efforts necessary for moving the inspection unit assembly 120 between the inspection operation position and the first and possibly the second maintenance position, the axis of rotation X may be extended in a direction substantially coinciding with the respective center of gravity of the inspection units 121 , 122. In such a way, almost all weight of the inspection units 121 , 122 is carried by the inspection unit connector 140 and the operator only has to provide forces exceeding the rotational friction. This rotation can be performed by hand or by any assisting actuator arrangement. The center of gravity may be adjusted to the axis mechanically by means of the inspection unit connector 140.

[0047] In cases the inspection unit assembly 120 comprises a control unit, it is preferred if the control unit also is arranged with the same axis of rotation X as the inspection units 121 , 122 to avoid cable loading. C.f. also Figure 8 further below.

[0048] The object handling system illustrated in Figure 1 is a sorting system. The inspection units 121 , 122 inspect the objects 111 , e.g. analyzes the chemical composition thereof, and based on this knowledge, a sorting arrangement can be controlled. In one embodiment, the object handling system thus further comprises a sorting unit assembly 130 of at least one, preferably at least two, sorting units 131 , 132. The sorting unit assembly 130 is positioned in a sorting operation position in a vicinity of the conveyor belt 110 downstream of the inspection operation position of the inspection unit assembly 120. The sorting unit assembly 130 is attached to the frame 160 by a sorting unit connector 134.

[0049] The sorting units 131 , 132 can be of different kinds, as such known in prior art. One example is that the sorting units 131 , 132 comprise means for providing a short air stream pulse, by which an object 111 arriving at the conveyor belt 110 can be displaced in a certain selectable direction. The sorting units 131 , 132 are then preferably provided just below the conveyor belt 110 at the end of the conveyor belt 110. Another example of a sorting unit 131 , 132 can be a mechanical unit, providing a mechanical pushing action to the different objects 111 in order to displace them in requested directions.

[0050] The operation of the sorting units 131 , 132 is preferably dependent on the outcome of the analysis made by the inspection units 121 , 122, and the sorting units 131 , 132 are therefore provided downstream of the inspection units 121 , 122. In other words, preferably, the inspection unit assembly 120 is positioned upstream of the maintenance bridge 161.

[0051] Common for most sorting units is that they typically are exposed to large amounts of contamination and then cleaning and maintenance requirements are typically high. To facilitate cleaning and maintenance, the sorting unit connector 134 is configured to allow a displacement of the sorting unit assembly 130. The sorting units 131 , 132 are moved from a sorting operation position to a third maintenance position accessible from the maintenance bridge 161. Such a situation is illustrated in Figure 2.

[0052] In this embodiment, the sorting unit connector comprises a bar 135. The sorting unit assembly 130 is attached to the frame 160 via the bar 135. The bar 135 is rotatably connected to the frame 160. When rotating the bar 135 at the sorting unit connector 134, the sorting unit assembly 130 will be moved from its sorting operation position. By a proper design of the bar 135 and the sorting unit connector 134, the sorting unit assembly 130 may be moved in such a way that the sorting units 131 , 132 will appear in a place that is easily accessible from the maintenance bridge 161 . In other words, the bar 135 is configured to fully or partly provide the displacement of the sorting unit assembly 130 from the sorting operation position to the third maintenance position upon a rotation of the bar 135.

[0053] In a sorting system, such as illustrated in Figures 1 and 2, the sorting unit assembly 130 is typically provided in the vicinity of the end of the conveyor belt 110. The space beyond and beneath the conveyor belt 110 typically comprises different arrangements for the further transport of sorted objects. When an operator is present on the maintenance bridge 161 , performing maintenance work, he / she typically needs tools and spare parts. There is a risk of dropping such objects or even for the operator himself / herself to fall down from the maintenance bridge 161. This is disadvantageous in all cases, but is typically more severe if the drop or fall occurs beyond the conveyor belt 110.

[0054] To this end, in a preferred embodiment, the frame 160 further comprise a protection screen 144, that is attached to the frame 160. This protection screen 144 is positionable in a protective position, as illustrated by Figure 1 , where the protection screen 144 extends upwards from the downstream edge of the maintenance bridge 161 . Thereby, the protection screen 144 at least partly closes an area 190 to the side of the maintenance bridge 161 . This thereby prevents persons falling or objects to be dropped from the maintenance bridge 161 into the object handling system through the area 190. The protection screen 144 is, as illustrated by Figure 2, movable from the protective position to a displaced position providing access to the sorting unit assembly 130 when the sorting unit assembly 130 is arranged in the third maintenance position. During maintenance, the sorting unit assembly 130 fills the area 190, at least to a major part, and prevents thereby objects to fall from the maintenance bridge 161 .

[0055] In other embodiments, e.g. if the object handling system 100 does not comprise the sorting unit assembly, the frame 160 may by positioned upstream of the inspection unit assembly 120.

[0056] Figure 4 is a flow diagram of steps of an embodiment of a method for maintaining an object handling system. In particular, the method is adapted to an object handling system as described above. In step S10, the inspection unit assembly is rotated to the first maintenance position. In step S12, maintenance is performed to the interior of the inspection unit via the inspection opening. In step S30, the inspection unit assembly is rotated to the inspection operation position.

[0057] In a preferred embodiment, where interior-access openings are available, the method comprises further steps. In step S20, the inspection unit assembly is rotated to the second maintenance position. In step S22, the lid is opened. In step S24, maintenance is performed to the interior of the inspection unit. In step S26, the lid is closed. In Figure 4, the steps S10 and S12 are illustrated to be performed before steps S20, S22, S24 and S26. However, the opposite relation is also possible, starting with the maintenance through the lid-covered interior-access openings before maintenance via the inspection openings. Both these alternatives are followed by step S30.

[0058] When a sorting system is available, maintenance of the sorting units may also be performed. Thus in one embodiment, the method for maintaining an object handling system comprises the further step S40, in which the sorting units are moved to the third maintenance position. In step S42, maintenance is performed to at least one sorting unit. In step S44, the sorting units are moved to the sorting operation position.

[0059] In Figure 4, the steps S40, S42 and S44 are illustrated to be performed after the inspection unit maintenance. However, in alternative embodiments, the steps S40, S42 and S44 may occur before and / or at least partially simultaneously or in parallel to the steps S10 to S30, since the different maintenance operations are basically independent of each other.

[0060] Steps S10 to S26 may be performed while the conveyor still is running which allows maintenance without stopping the flow of the entire industrial facility, e.g. a sorting plant. This might be beneficial for making maintenance of inspection units less detrimental to the operation of the entire industrial facility.

[0061] As mentioned above, it is preferred to have latch configured to releasably fixate the inspection unit assembly in at least the inspection operation position. In such a case, the method preferably also comprises step S8, in which the inspection unit assembly positioned in the inspection operation position is unlocked. In other words, the latch is released. Thereby, the rotation in step S10 becomes possible. Analogously, the method preferably also comprises step S32, in which the inspection unit assembly is locked again in the inspection operation position, e.g. by the latch.

[0062] The easy access to different parts of the inspection units and the sorting system from the bridge opens up for quick maintenance work, which significantly reduces the time the industrial facility has to be closed down. This in turn leads to large economic advantages. The object handling system presented here above also have advantages during assembling of the system. The conveyor belt can e.g. be used as assembling table and the sorting unit connector could be used for moving the assembly into the sorting operation position. By having the inspection unit assembly possibly comprising several inspection units, the weight of each piece to be mounted can be reduced. Typically, a maximum recommended weight for components to be mounted or serviced is 40 kg for men and 20 kg for women. By dividing the inspection arrangements into parts units, typically identical part units, the entire width of a broad conveyor belt can be covered. By using identical part units, spare part units can be used for replacing any of the part units, thereby reducing the need for spare part storage. The inspection units may then be assembled into an inspection unit assembly, typically connected by a structural member. The inspection unit assembly can then be assembled directly in place using the maintenance bridge. Any need for overhead crane facilities may be reduced to the actual transportation to the location of the mounting. An analogue division into part units of the sorting unit assembly may also be applied in order to reduce the loads during mounting and service.

[0063] Figure 5 illustrates schematically a situation in the beginning of the assembling procedure. The frame 160, except the maintenance bridge, is provided across the conveyor belt 110. The sorting units 131 , 132 are resting on the conveyor belt 110 and are assembled into a sorting unit assembly 130. The sorting unit connector 135, being connected to the sorting unit assembly 130, is attached also to the frame 160 by means of the sorting unit connector 134.

[0064] Figure 6 illustrates the situation when the sorting units 131 , 132 are moved to the sorting operation position by use of the sorting unit connector 135. The sorting unit connector 135 is in this embodiment rotated around the axis R. Preferably, the object handling system 100 comprises a lifting arrangement 145 attached to the frame 160. The lifting arrangement 145 is configured for assisting in moving the sorting units 131 , 132.

[0065] This lifting arrangement 145 may also be useful for maintenance purposes. The sorting unit assembly 130 may be heavy and the lifting arrangement 145 may therefore be useful for reducing the load on the maintenance person. To this end, the lifting arrangement 145 is configured for assisting in moving the sorting units 131 , 132 from the sorting operation position to the third maintenance position. More preferably, the lifting arrangement 145 is an automatic lifting arrangement for the sorting unit assembly 130.

[0066] In Figure 7, the maintenance bridge 161 is mounted to the frame 160. A structural member 128 of the inspection unit assembly is mounted to the inspection unit connector. This work can be performed from the newly mounted maintenance bridge 161.

[0067] Finally, in Figure 8, the inspection units 121 , 122 are assembled into the structural member 128. Also this work is by advantage made from the maintenance bridge 161 . Since the structural member 128 of the inspection unit assembly 120 is in place before the assembling of the inspection units 121 , 122, the inspection units 121 , 122 can be brought in place one at a time, thereby reducing the weight of the necessary lifting operations. A control unit 170, connected by electrical and signaling cables 172, is provided, controlling the operation of the inspection units 121 , 122.

[0068] In some systems, rolling items might occur on the conveyor belt. In such situations, minor vibrations or acceleration / retardation may cause the item to shift in position. An inspection unit may detect a certain item at a certain position. However, when the item has been further transported downstream to a following process stage, the position of the item may have been changed. In such application it may be of interest to minimize the transport distance between an inspection unit and any following downstream process mechanisms.

[0069] To this end, as illustrated in Figure 9B, in one embodiment, the maintenance bridge 161 and first parts 162 of the frame 160 supporting the maintenance bridge 161 are displaceable. Also other parts 165 that crosses the width of the maintenance bridge 161 may be displaceable. The displaceable feature may be obtained by folding and / or rotating the maintenance bridge 161 and first parts 162 of the frame 160 into a substantially vertical orientation perpendicular to the transport direction, thereby occupying a smaller volume in the transport direction. The maintenance bridge 161 and first parts 162 of the frame 160 may alternatively or in addition be slided in the transport direction. Furthermore, second parts 163 of the frame 160 supporting the inspection unit assembly 120 are slidable in the transportation direction T. In Figure 9B, this is illustrated by the sliding mechanism 164 following a floor rail of the frame 160. By these arrangements, a positioning of the inspection unit assembly 120 is allowed to be shifted or displaced in the transportation direction T. During maintenance, the position of the inspection unit assembly 120 may be provided as illustrated in Figure 9B, giving space for the maintenance bridge to be folded up and used for supporting the maintenance staff. Figure 9A illustrates the situation during operation. The foldability and slidability allows the inspection unit assembly 120 to be positioned further downstream during an operation mode than during a maintenance mode. The first parts 162 and the maintenance bridge 161 are then folded, in the figure behind the frame 160, and the second part 163 has been slidd downstream.

[0070] Figure 10 is a flow diagram of steps of an embodiment of a method for assembling an object handling system having sorting units and an inspection unit assembly possibly comprising a number of inspection units. In step S50, the frame is provided across the conveyor belt. In step S52, the sorting unit assembly is assembled with the sorting units resting on the conveyor belt. In step S54, the sorting unit connector is attached to the frame. In step S56, the sorting units are moved to the sorting operation position by use of the sorting unit connector. In step S58, the maintenance bridge is mounted to the frame. In step S60, a structural member of the inspection unit assembly is mounted to the inspection unit connector. In step S62, the inspection units are assembled into the structural member.

[0071] Preferably, if necessary, a step S61 may be performed, in which a center of gravity for the inspection unit assembly is adjusted relative to an axis of rotation of the inspection unit assembly. This may e.g. be performed by means of an inspection unit connector.

[0072] The embodiments described above are to be understood as a few illustrative examples of the present invention. It will be understood by those skilled in the art that various modifications, combinations and changes may be made to the embodiments without departing from the scope of the present invention. In particular, different part solutions in the different embodiments can be combined in other configurations, where technically possible. The scope of the present invention is, however, defined by the appended claims.

Claims

CLAIMS1. An object handling system (100) for handling objects (111 ) transported by a conveyor belt (110) in a transportation direction (T), said object handling system comprising; an inspection unit assembly (120) comprising at least one inspection unit (121 , 122) connected by a structural member (128), each of which having a respective inspection opening (123); a frame (160) configured for being arranged across the conveyor belt (110); said frame (160) comprising a maintenance bridge (161 ), extending across a width of the conveyor belt (110) and being configured to support a weight of a human operator; wherein the inspection unit assembly (120) is positioned above the conveyor belt (110) and rotatably attached to the frame (160) by an inspection unit connector (140); and wherein the inspection unit connector (140) is configured to allow a rotation of the inspection unit assembly (120) around an axis of rotation (X), whereby the inspection opening (123) of the inspection units (121 , 122) are rotatable from an inspection operation position facing the conveyor belt (110) to a first maintenance position facing a space above the maintenance bridge (161 ).

2. The object handling system according to claim 1 , characterized in that said inspection unit assembly (120) comprises at least two inspection units (121 , 122).

3. The object handling system according to claim 1 or 2, characterized in that said inspection opening (123) comprises an optical window (126), wherein said first maintenance position facing a space above the maintenance bridge (161 ) enables cleaning of said optical window (126).

4. The object handling system according to any of the claims 1 to 3, characterized in that each of the inspection units (121 , 122) has one or more interior-access openings (124) providing access into the interior of the inspection unit, and a lid (125)covering the interior-access opening (124), and wherein the inspection unit connector (140) is configured such that the internal-access opening (124) of the inspection units (121 , 122) are rotatable to a second maintenance position facing a space above the maintenance bridge (161 ).

5. The object handling system according to claim 4, characterized in that said second maintenance position facing a space above the maintenance bridge (161 ) enables replacement of wear and tear parts.

6. The object handling system according to any of the claims 1 to 5, characterized in that inspection unit connector (140) comprises a latch configured to releasably fixate the inspection unit assembly (120) in the inspection operation position and in the first maintenance position and, if being dependent on claim 4 or 5, also in the second maintenance position.

7. The object handling system according to any of the claims 1 to 6, characterized by further comprising a sorting unit assembly (130) of at least one sorting units (131 , 132); wherein the sorting unit assembly (130) is positioned in a sorting operation position in a vicinity of the conveyor belt (110) downstream of the inspection operation position of the inspection unit assembly (120) and attached to the frame (160) by a sorting unit connector (134); wherein the sorting unit connector (134) is configured to allow a displacement of the sorting unit assembly (130), whereby the sorting units (131 , 132) are moved from a sorting operation position to a third maintenance position accessible from the maintenance bridge (161 ); and wherein the inspection unit assembly (120) is positioned upstream of the maintenance bridge (161 ).

8. The object handling system according to claim 7, characterized in that the sorting unit connector comprises a bar (135), and said sorting unit assembly (130) is attached to said frame via said bar (135), which bar is rotatably connected to said frame (160), and wherein said bar is configured to fully or partly provide saiddisplacement of the sorting unit assembly (130) from the sorting operation position to the third maintenance position upon a rotation of the bar (135).

9. The object handling system according to claim 7 or 8, characterized in that the frame (160) further comprise a protection screen (144) attached to the frame, which protection screen is positionable in a protective position where the protection screen (144) extends upwards from the downstream edge of the maintenance bridge (161 ), thereby at least partly closing an area (190) to the side of the maintenance bridge and thereby preventing persons falling or objects to be dropped from the maintenance bridge into the object handling system through the area (190), and wherein the protection screen (144) is movable from the protective position to a displaced position providing access to the sorting unit assembly (130) when the sorting unit assembly (130) is arranged in the third maintenance position.

10. The object handling system according to claim 9, characterized by further comprising a lifting arrangement (145) attached to the frame (160) and configured for assisting in moving the sorting units (131 , 132) from the sorting operation position to the third maintenance position.

11. The object handling system according to claim 10, characterized in that the lifting arrangement (145) is an automatic lifting arrangement for the sorting unit assembly (130).

12. The object handling system according to any of the claims 1 to 6, characterized in that the frame (160) is positioned upstream of the inspection unit assembly (120).

13. The object handling system according to any of the claims 1 to 12, characterized in that said axis of rotation (X) extends in a direction substantially coinciding with the respective a center of gravity of the inspection units (121 , 122).

14. The object handling system according to any of the claims 1 to 13, characterized in that the inspection unit assembly (120) further comprises a control unit (170), thereby being arranged with the same axis of rotation (X) as the inspection units (121 , 122).

15. The object handling system according to claim 14, characterized in that the control unit (170) comprises at least one inspection unit lock sensor configured for determining whether the inspection unit assembly (120) is locked into the inspection operation position, wherein the control unit (170) is configured for providing an output signal representing a lock status.

16. The object handling system according to any of the claims 1 to 15, characterized in that the maintenance bridge (161 ) and first parts (162) of the frame (160) supporting the maintenance bridge (161 ) are displaceable, and second parts (163) of the frame (160) supporting the inspection unit assembly (120) are slidable in the transportation direction (T), allowing a positioning of the inspection unit assembly (120) further downstream during an operation mode than during a maintenance mode.

17. An industrial facility for processing large amounts of material or objects, characterized by comprising a conveyor belt and an object handling system according to any of the claims 1 to 16 arranged across the conveyor belt.

18. The industrial facility according to claim 17, characterized in that the object handling system is an object handling system according to claim 15, wherein the industrial facility further comprises a supervising control configured for communicating with the control unit (170) of the inspection unit assembly (120).

19. A method for maintaining an object handling system according to any of the claims 1 to 16 or an industrial facility according to claim 17 or 18, comprising the steps of:- rotating (S10) the inspection unit assembly (120) to the first maintenance position;- performing (S12) maintenance to the interior of the inspection unit via the inspection opening (123); and- rotating (S30) the inspection unit assembly (120) to the inspection operation position.

20. The method for maintaining an object handling system according to claim 19 when being applied to an object handling system according to claim 4, characterized by the further steps of:- rotating (S20) the inspection unit assembly (120) to the second maintenance position;- opening (S22) the lid (125);- performing (S24) maintenance to the interior of the inspection unit (121 , 122); and- closing (S26) the lid (125).21 . The method for maintaining an object handling system according to claim 19 or 20 when being applied to an object handling system according to claim 7, 8 or 9, characterized by the further steps of:- moving (S40) the sorting units (131 , 132) to the third maintenance position;- performing (S42) maintenance to at least one sorting unit (131 , 132); and- moving (S44) the sorting units (131 , 132) to the sorting operation position.22 A method for assembling an object handling system according to any of the claims 7 to 9, comprising the steps of:-providing (S50) the frame (160) across the conveyor belt (110);- assembling (S52) the sorting unit assembly (130) with said sorting units (131 , 132) resting on the conveyor belt (110);- attaching (S54) the sorting unit connector (134) to the frame (160);- moving (S56) the sorting units (131 , 132) to the sorting operation position by use of the sorting unit connector (134);- mounting (S58) the maintenance bridge (161) to the frame (160); and- mounting (S60) a structural member (128) of the inspection unit assembly (120) to the inspection unit connector (140);- assembling (S62) the inspection units (121 , 122) into the structural member(128).

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