Abstract:
A method inspects a conveyor ( 10 ) having opposing sides ( 34, 35 ) and a length. The conveyor includes an endless belt ( 16 ) and a plurality of roller structures ( 24 ) disposed in spaced relation along at least a portion of the length of the conveyor and under a top flight ( 17 ) of the belt for supporting the belt while material is being conveyed on the belt. Each roller structure includes at least one roller ( 12, 12′ ) constructed and arranged to rotate about an axis as the belt is conveyed with the material. The method orients an unmanned vehicle ( 22 ), having sensor structure ( 28 ) thereon, at one side of the conveyor, and causes the vehicle to travel along the portion of the length of the conveyor while the sensor structure obtains data regarding a state of at least a portion of the belt and of rollers of the plurality of roller structures while the conveyor is operating.

Description:
FIELD 
       [0001]    The invention relates to conveyor inspection and, more particularly, to an unmanned vehicle carrying sensor structure that travels alongside the moving conveyor to inspect the conveyor belt and rollers. 
       BACKGROUND 
       [0002]      FIG. 1  shows a sectional view of a portion of a conventional large conveyor, generally indicated  10 , which is typically used in mining operations. A set of idlers or upper rollers is carried by a frame  14  and include outer rollers  12  and a central roller  12 ′. The rollers  12 ,  12 ′ rotate with respect to the moving, endless belt  16  that carries the material  18 . The rollers  12 ,  12 ′ are provided to ensure that the belt  16  defines a trough for the material  18 . A plurality of sets of the rollers is spaced to support the belt  16  along the length of the conveyor  10 . Lower rollers  20  support the returning portion of the belt  16 ′. 
         [0003]    There is wear and abrasion on the belt  16  caused by slip, friction, material movement, static and dynamic pulling forces, and environmental conditions. Additionally, the belt  16  may be damaged by misalignment, and by foreign material. A downtime due to belt failure may cause significant production losses. Therefore it is important to detect problems before they cause larger belt damage. Typical indications of upcoming belt failures are small cracks at the edges and at the underside where it bends to trough shape. 
         [0004]    Furthermore, failure of the idlers or rollers  12 ,  12 ′ and their roller bearings causes friction and abrasion. The bearings fail with increasing temperature. A typical lifetime specification of a bearing at 70° C. is 22600 h, but this drops dramatically at higher temperatures (5600 h at 100° C., 2200 h at 120° C.). Factors that cause temperature increase are e.g., quality of manufacturing and assembly, rotation speed, radial load from belt, distance between idlers, grease viscosity, seal, handling and storage of idlers. Typical criteria for replacing idlers are: take note at 70° C., plan replacement at 80° C., and replace above 90° C. 
         [0005]    Currently, conveyors are inspected periodically by personnel walking or driving along the length of the conveyor and visually checking for problems. Some inspection crews use thermal cameras to detect the hot spots of failing rollers and roller bearings. Alternatively, conventional automatic inspection systems are usually fixed installations above the belt that measure belt thickness, misalignment or rips at the belt edges. These systems cannot inspect the rollers since the required sensors would be too expensive in that it would not be cost-effective to fix many sensors along the length of the conveyor. Still further, maintenance trolley systems are used that hang from the conveyor. However, since these systems are connected to the conveyor, they are not readily adaptable for use on different conveyors. 
         [0006]    Thus, there is a need to provide an unmanned vehicle that is travels adjacent to the operating conveyor to inspect the conveyor. There is also a need to provide a sensor structure that travels adjacent to the operating conveyor in a guided manner to inspect the conveyor. 
       SUMMARY 
       [0007]    An object of the invention is to fulfill the needs referred to above. In accordance with the principles of the present invention, this objective is obtained by a method of inspecting a conveyor having opposing sides and a length. The conveyor includes an endless belt and a plurality of roller structures disposed in spaced relation along at least a portion of the length of the conveyor and under a top flight of the belt for supporting the belt while material is being conveyed on the belt. Each roller structure includes at least one roller constructed and arranged to rotate about an axis as the belt is conveyed along with the material. The method orients an unmanned vehicle, having sensor structure thereon, at one side of the conveyor, and causes the vehicle to travel along the portion of the length of the conveyor while the sensor structure obtains data regarding a state of at least a portion of the belt and of rollers of the plurality of roller structures while the conveyor is operating. While the vehicle is traveling, the sensor structure obtains the data only while being adjacent to the one side of the conveyer, without moving under the top flight of the belt. 
         [0008]    In accordance with another aspect of the disclosed embodiment, the objective is obtained by a method of inspecting a conveyor having opposing sides and a length. The conveyor includes an endless belt and a plurality of roller structures disposed in spaced relation along at least a portion of the length of the conveyor and under a top flight of the belt for supporting the belt while material is being conveyed on the belt. Each roller structure includes at least one roller constructed and arranged to rotate about an axis as the belt is conveyed with the material. The method provides guide structure along the length of the conveyor disposed adjacent to at least one of the sides of the conveyor. Sensor structure is carried by the guide structure. The sensor structure is caused to move in manner guided by the guide structure along the length of conveyor with the sensor structure obtaining data regarding a state of at least a portion of the belt and of rollers of the plurality of roller structures while the conveyor is operating. 
         [0009]    Other objects, features and characteristics of the present invention, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of this specification. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The invention will be better understood from the following detailed description of the preferred embodiments thereof, taken in conjunction with the accompanying drawings, wherein like reference numerals refer to like parts, in which: 
           [0011]      FIG. 1  is a sectional view of a portion of a conventional conveyor showing the belt and upper and lower rollers thereof. 
           [0012]      FIG. 2  is a schematic view of a portion of a forward flight of a conveyor with an unmanned vehicle, carrying sensor structure in a pan and tilt arrangement, to inspect rollers at a side of the conveyor in accordance with an embodiment. 
           [0013]      FIG. 3  is a thermal scan of a roller of the conveyor of  FIG. 2  using the sensor structure. 
           [0014]      FIG. 4  is a schematic view of a portion of a forward flight of a conveyor with an unmanned vehicle having a robotic arm carrying sensor structure to inspect rollers at a side of the conveyor in accordance with another embodiment. 
           [0015]      FIG. 5  is side schematic view of a conveyor with guide structure, in the form of a cable carrying sensor structure, at a side of the conveyor to inspect rollers and an underside of the conveyor belt, in accordance with another embodiment. 
           [0016]      FIG. 6  is a sectional view taken along the line  6 - 6  in  FIG. 5 . 
           [0017]      FIG. 7  is a sectional view taken along the line  7 - 7  in  FIG. 5 . 
           [0018]      FIG. 8  is a view of a portion of the guide structure, in the form of a cable, which carries the sensor structure in accordance with an embodiment. 
           [0019]      FIG. 9  is a schematic sectional view of a portion of the guide structure, in the form of a track, which carries the sensor structure in accordance with another embodiment. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0020]    With reference to  FIG. 2 , a schematic view of a portion of a forward flight of a conveyor is shown, generally indicated at  10 , being inspected by an unmanned vehicle, generally indicated at  22 . The conveyor  10  is conventional and is preferably of the type shown in  FIG. 1 , having a plurality of roller sets or roller structures  24  carried by the frame  14  under a top flight  17  of the belt  16 . Each roller structure  24  preferably includes the two outer rollers  12  and the central roller  12 ′ of  FIG. 1 . Each roller  12 ,  12 ′ rotates about an axis A via bearings  13  as the endless belt  16  is conveyed along with material  18 . The return flight of the belt  16 , the lower rollers  20 , and the material  18  being conveyed are not shown in  FIGS. 2 and 4 . Alternatively, the roller structure can comprise two or four rollers. 
         [0021]    As noted above, wear and abrasion of the belt  16  is caused by slip, friction, material movement, belt deformation, static and dynamic stretching forces, and environmental conditions. Additionally, the belt  16  may be damaged by misalignment and foreign material. Furthermore, failure of the idlers or rollers  12 ,  12 ′ and roller bearings causes friction and abrasion. The bearings fail with increasing temperature. Therefore, a conveyor  10  is inspected regularly to detect problems before they result in downtime and larger damage. In accordance with an embodiment and as shown in  FIG. 2 , the unmanned vehicle  22  is provided to travel along at least a portion of a length L of the conveyor  10  to inspect the belt  16  and rollers  12 ,  12 ′ of the plurality of roller sets  24  while the conveyor  10  is operating. 
         [0022]    The unmanned vehicle  22  may be conventional, such as of the type disclosed in U.S. Pat. No. 7,784,570 B2, having a platform  26  carrying sensor structure, generally indicated at  28 . In the embodiment of  FIG. 2 , the sensor structure  28  includes an imaging sensor  30  disposed on mounting structure  29 . In the embodiment of  FIG. 2 , the mounting structure  29  is a conventional pan and tilt mechanism  32  so as to be capable of motion in two degrees of freedom: rotation in a horizontal plane and in a vertical plane. The imaging sensor  30  is preferably a thermal imaging camera aimed at the roller structure  24  to capture visual and thermal images of the rollers  12 ,  12 ′ of each roller structure  24  as the vehicle  22  travels along a side  34  of the operating conveyor  10 .  FIG. 3  is a thermal image captured by the imaging sensor  30  of  FIG. 2 , showing a hot spot  36  of a roller  12 . The hot spot  36  indicates heat generated by friction which may indicated that the bearing of the roller  12  is damaged. A viewing angle of the imaging sensor  30  can be such that at least a portion of the underside of the belt  16  can be monitored to determine if there are defects in this belt portion. 
         [0023]    In addition, the sensor structure  28  may include an acoustic sensor  37  to obtain acoustic signals along the length of the belt  16  as the vehicle  22  moves along the side  34  or  35  of the conveyor  10 . Conventional frequency spectrum analysis of the acoustic data can be used to determine an abnormal pattern, for example, caused by jammed rollers  12 ,  12 ′, or screeching of the belt  16 . The sensor structure  28  may contain structure for obtaining thermal imaging data, infrared imaging data, visual imaging data, acoustic data or any combination of this data. If the data is thermal, infrared or visual, the sensor structure  28  may have zoom capabilities and can have an automatic or remote controllable focus. 
         [0024]    Preferably, a wireless transceiver  35  on the sensor structure  28  or vehicle can communicate with a wireless receiver  38  that is provided on or near the conveyor  10 . The receiver  38  receives signals  40  to thereby associate data that is captured by the imaging sensor  30  or the acoustic sensor  37  with position, so as to determine what part of the belt  16  or which roller  12 ,  12 ′, of a set  24  is damaged or not functioning properly. Instead of transmitting the images or data, they can be stored in memory  42  that is provided on the vehicle  22  or that is part of the sensor structure  28 , for later downloading. 
         [0025]    The vehicle  22  can be controlled autonomously by an onboard control system  43  such as, for example, as disclosed in U.S. Pat. No. 7,499,776 B2. Alternatively, the vehicle can be controlled remotely by an operator using a remote control unit  44  such as, for example, as disclosed in U.S. Pat. No. 7,926,598 B2 or by GPS navigation. Manual and semi-autonomous control of the vehicle  22  is also contemplated. The content of each of U.S. Pat. No. 7,784,570 B2, U.S. Pat. No. 7,499,776 B2 and U.S. Pat. No. 7,926,598 B2 is hereby incorporated by reference into this specification. In another embodiment, a remote operator can take control of the system at any time during an autonomous inspection, such as when the system detects a problem. This would allow the remote operator to do a more thorough manual inspection of the equipment of interest. 
         [0026]    With reference to  FIG. 4 , instead of mounting the imaging sensor  30  and the acoustic sensor  37  on the two degree of freedom pan and tilt mechanism  32 , the mounting structure  29 ′ comprises a robot  46  that carries the sensors  30  and  37  for movement in more than two degrees of freedom. In the embodiment, the robot  46  has six degrees of freedom. This provides more mobility so as to move the sensors  30 ,  37  to ensure they are adjacent to the roller sets  24  as the vehicle  22  traverses changing terrain. Instead of providing the robot, the sensors  30  and  37  can be mounted on an extendable arm such as the Packbot ® from iRobot Corp®. Preferably, the arm can be extended only when the vehicle  22  is stopped to closely monitor a point of interest on the conveyor  10 . If desired, the arm can be extended to reach under the belt. 
         [0027]    Since there are many portions of the frame  14  along the length of the conveyor  10  making it difficult to move the sensor structure  28 ′ under the top flight  17  of the belt  16 , the sensor structures  28  or  28 ′ inspect only while being adjacent to a side  34  or  35  of the conveyer  10 , without the need to move under the top flight of the belt  16 . Once the vehicle  22  obtains data from one side  34  of the conveyor  10 , the vehicle can move to the other side  35  and obtain data from that side while the conveyor  10  is in operation. As a result, more accurate data collection can be obtained from each of the outer rollers  12 . It is noted that sensing of a roller  12 ,  12 ′ of any set  24  may not occur due to accidentally being missed or because of the viewing angle, is not accessible, etc. In such cases, later attempts can be made to sense these missed rollers. 
         [0028]    Any other unmanned vehicle capable of moving along rough terrain can be used to carry the sensor structures  28  or  28 ′. Alternatively, with reference to  FIG. 4 , a remote controlled flying vehicle such as a miniature helicopter or drone, generally indicated at  22 ′, including the sensor structure  28  on platform  26 ′, can be used instead of the vehicle  22  that has ground-engaging structure such as tracks or wheels  48 . The vehicle  22 ′ can be controlled to fly adjacent to the conveyor  10  near the outer rollers  12 . The sensor structure  28 ′ can be mounted on the platform  26 ′ in the manner discussed above using regard to mounting structure  29  or  29 . Furthermore, if the vehicle  22  is controlled by the remote control unit  44 , the unit  44  can also control movement of the pan and tilt mechanism  32  or the robot  46 . 
         [0029]    Instead of fixing the acoustic sensor  37  to the sensor structure  28 , the sensor  37  can be thrown, ejected or shot from the vehicle  22  onto a portion of the conveyor  10 . Data from the sensor  37  can be transmitted through a connected wire and after the data reading, the sensor  37  can be recovered by coiling up the wire. Although a large mining conveyor  10  is disclosed as being inspected by the vehicle  22 , the vehicle can inspect any type of conveyor. 
         [0030]    The vehicle  22  with sensor structure  28  allows automatic and cost efficient inspection of the rollers and the belt of a conveyor to detect problems before belt failure and larger damages occur. Advantageously, inspections can be performed automatically and accurately with reduced or no manual intervention. Also, when anomalies are detected during the inspection, the sensor structure  28  can automatically perform additional measurements by viewing the problem area from additional angles and/or using additional sensors such as the acoustic sensor  37 , or other sensors. Also, while moving alongside the conveyor, the sensor structure  28  can also be used to detect any other unusual sound or image not originating from the rollers but from other parts of the installation. 
         [0031]    The vehicle  22  with sensor structure  28  thereon is also advantageous over conventional maintenance trolley systems in that the unmanned vehicle  22  with sensor structure  28  is not coupled to the conveyor  10 . Therefore, the same inspection system can be used for a wider variety of conveyors. The vehicle is also more flexible in that the positions and angles of the inspection are not limited by the trolley configuration since the vehicle and movable mounting structure that carries the sensor structure  28  has more freedom of movement. 
         [0032]    With reference to  FIG. 5 , a schematic view of a conveyor, generally indicated at  10 , is shown with an associated inspection system, generally indicated at  11 ′, to inspect rollers and an underside of the conveyor belt, in accordance with an embodiment. The inspection system  11 ′ comprises guide structure  122 , carrying sensor structure generally indicated at  124 , disposed adjacent to at least one side of the conveyor  10 ′. The conveyor  10 ′ is conventional and is preferably of the type shown in  FIG. 1 , having a plurality of roller sets or roller structures  126  carried by the frame  14  under a top flight  15  of the endless belt  16 . Each roller structure  126  preferably includes the two outer rollers  12  and the central roller  12 ′ as shown in  FIG. 6 . Each roller  12 ,  12 ′ rotates about an axis A via bearings  13  as the endless belt  16  is conveyed along with material  18 . The return flight of the belt  16 ′ is supported by the lower rollers  20  ( FIG. 4 ). Alternatively, the roller structure  126  can comprise two or more rollers. 
         [0033]    Drive structure, generally indicated at  128 , is provided for moving the belt  16 . In the embodiment, the drive structure includes a first pulley  130  at a first end  132  and a second pulley  134  at the second end  136  of the conveyor  10 ′. At least one of the pulleys is powered. In the embodiment, a motor  138  drives the first pulley  130 . A conventional belt tensioning roller  140  engages the return flight of the belt  16 ′. The roller  140  is adjustable to adjust the tension in the belt  16 ′. 
         [0034]    As noted above, wear and abrasion of the belt  16  is caused by slip, friction, material movement, belt deformation, static and dynamic stretching forces, and environmental conditions. Additionally, the belt  16  may be damaged by misalignment and foreign material. Furthermore, failure of the idlers or rollers  12 ,  12 ′ and roller bearings causes friction and abrasion. The bearings fail with increasing temperature. Therefore, a conveyor  10 ′ is inspected regularly to detect problems before they result in downtime and larger damage. In accordance with an embodiment and as shown in  FIG. 5 , the guide structure, generally indicated at  122 , carries the sensor structure  124  in a guided manner along the length L of the conveyor  10 ′ to inspect the belt  16  and rollers  12 ,  12 ′ of the plurality of roller sets  126  while the conveyor  10 ′ is operating. 
         [0035]    The guide structure  122  includes a plurality of supports  142  that are fixed to at least one side of the frame  14  of the conveyor  10 ′ and spaced along a length of the frame  14 . In the embodiment of  FIGS. 6-8 , each support  142  includes a roller  144  for supporting a cable  146  that extends along the length L of the conveyor  10 ′. The cable  146  is moved by a pulley  148  driven by a motor  150  or by other systems for moving a cable. 
         [0036]    The sensor structure  124  includes a vehicle or carrier  152  that moves together with the cable  146  in a guided manner in the directions B of  FIG. 8 . The sensor structure  124  also includes an imaging sensor  154  disposed on the carrier  152  for movement therewith. The imaging sensor can be mounted to the carrier  152  using a conventional pan and tilt mechanism so as to be capable of motion in two degrees of freedom: rotation in a horizontal plane and in a vertical plane. The imaging sensor  154  is preferably a thermal imaging camera (capable of zooming) aimed at the roller structure  126  to capture visual and thermal images of the rollers  12 ,  12 ′ of each roller structure  126  and underside of the belt  16  as the carrier, with sensor  154 , travels along a side of the operating conveyor  10 ′. The imaging sensor  154  of  FIG. 5  can be used to capture a thermal image (such as shown in  FIG. 3 ) that indicates a hot spot  36  of a roller  12 . The hot spot  36  indicates heat generated by friction which may indicated that the bearing of the roller  12  is damaged. The field of view  158  of the sensor  154  is such that the roller structures  126  and at least a portion of the underside of the belt  16  (see  FIG. 7 ) can be monitored to determine if there are defects in the monitored belt portion, particularly at the bent areas  160  of the belt  16 . Instead of or in addition to a thermal image camera, the imaging sensor  154  can be a visual image camera or a camera with sensitivity in the near infrared. In addition, or in the alternative, the sensor structure  124  can include a microphone such a directional microphone for obtaining acoustic signals from the conveyor  10 ′. More than one sensor structure  124  can be provided on the cable  146 . Also, it can be appreciated that a guide structure  122  and associated sensor structure(s)  124  can be provided on each side of the conveyor. Furthermore, instead of moving the cable  146 , the cable can be static and the carrier  152  can be self-propelled. 
         [0037]    Preferably, a wireless transceiver  162  ( FIG. 7 ) on the sensor structure  124  permits the transfer of data to and from the sensor structure  124 . The transceiver  162  receives signals to thereby associate data that is captured by the imaging sensor  154  with position, so as to determine what part of the belt  16  or which roller  12 ,  12 , of a set  126  is damaged or not functioning properly. Instead of transmitting the images or data, they can be stored in memory that is provided on the sensor structure  124  for later downloading. 
         [0038]    With reference to  FIG. 9 , another embodiment of an inspection system is shown generally indicated at  11 ″. The system  11 ″ comprises guide structure  122 ′ and sensor structure  124 ′. The guide structure  122 ′ includes a plurality of supports  142 ′ that are fixed to at least one side of the frame  14  of the conveyor  10 ′ and spaced along a length of the frame  14  (similar to supports  142  in  FIG. 5 ). A guide rail  164  is fixed by bolts  166  or the like to the supports  142 ′ and extends along at least one side of the conveyor  10 ′. The guide rail  164  is a rigid track, preferably of T-shape. The sensor structure  124 ′ includes a carrier  152 ′ that moves along the guide rail  164  in a guided manner. In particular, the carrier  152 ′ includes a first set of rollers  168  engaged with opposing surfaces  170 ,  172  at one end of the horizontal leg of the T-shaped rail  164 , a second set of rollers  174  engaged with the opposing surfaces  170 ,  172  at the other end of the horizontal leg of the T-shaped rail  164 , a third set of rollers  176  engaged with opposing surfaces  178 ,  180  of the vertical leg of the T-shaped rail  164 . The sets of carrier rollers  168 ,  174 ,  176  permit guided movement of the carrier  152 ′ along the guide rail  164 . At least one of the rollers, e.g., roller  174 ′ is driven by an electric motor  182  to propel the carrier  152 ′ along the rail  164 . A battery  184  powers the motor  182 . Alternatively, a solar panel can provide power to the motor  182 , or an electrical connector can be provided to connect the motor  182  to an external power supply. Other ways to move the carrier  152 ′ along the rail  164  are possible, such as air propulsion, or a motor driven pulley system. 
         [0039]    The imaging sensor  154  is mounted on the carrier  152 ′. A battery-powered light source  186  can be provided on the carrier  152 ′ to create defined lighting conditions at the underside of the belt  116 . A pan and tilt unit can be provided for the imaging sensor  154  and/or the light source  186 . The wireless transceiver  162  on the sensor structure  124 ′ permits the transfer of data to and from the sensor structure  124 ′ and can control the motor  182  remotely for moving the carrier  152 ′. A housing  188  of the carrier  152 ′ provides an enclosure for the imaging sensor  154  so as to protect the imaging sensor  154  from harsh outdoor conditions. Heating or cooling systems can be provided in the housing  188 . A sunshield  190  can be provided to ensure that the imaging sensor  154  operates under the most optimum lighting conditions. An acoustic sensor or microphone  191  can be mounted on the sunshield  191  or other part of the sensor structure  124 ′. A viewing window  192  is provided in the housing  188 , through which the imaging camera obtains images. A wiper  194  with a spray cleaner can be provided to clean the window  192 . Also, while moving alongside the conveyor, the acoustic sensor  191  can also be used to detect any other unusual sound or image not originating from the rollers but from other parts of the installation. 
         [0040]    The sensor structure  124 ,  124 ′ movable on the guide structure  122 ,  122 ′ allows inspection of all load carrying rollers  12 ,  12 ′ and may also allow inspection of the lower support rollers  20 . The imaging sensor  154  can take either videos or snapshot photos. This data is either recorded for later evaluation or transmitted to an inspection terminal and observed or recorded there. The microphone  191  takes audio readings of the turning rollers and the audio signal is recorded for later evaluation or transmitted to an inspection terminal and observed or recorded there. Optionally there is automatic data processing (e.g., spectrum analysis of audio data) that flags irregularities that may indicate a damaged roller or belt rips that need to be looked at by an operator. It is noted that sensing of a roller  12 ,  12 ′ or  20  may not occur due to accidentally being missed or because of the viewing angle, is not accessible, etc. In such cases, later attempts can be made to sense these missed rollers. 
         [0041]    There are various ways to correlate the recorded data with the location at the conveyor  10 ′ where they were taken. For example, visual markers can be provided at the conveyor  10 ′, such as numbers painted on the structure. If the cable  146  is pulled forward or backward, position encoders can be provided at the driving pulley  148  that coils up the cable. If initial position and travelling speed is known, a timestamp on the recorded data can be correlated to the location. If a GPS receiver  165  ( FIG. 9 ) is available in the carrier  152 ′, a timestamp on the recorded data can be correlated to the location. If initial position is known, the rollers can be counted as they pass through the field of view of the imaging sensor  154 . This can either be done with simple image processing during recording or during later evaluation. The data recording can be automatic stopped when the sensor structure  124 ′ reaches the end of the conveyor  10 ′. 
         [0042]    The guide structure  122  and associated sensor structure  124  allows automatic and cost efficient inspection of the rollers and the belt of a conveyor to detect problems before belt failure and larger damages occur. Advantageously, inspections can be performed automatically and accurately with reduced manual intervention. Manual work is only required for placing and collecting the sensor structure  124 . The quality of inspection is improved since the rollers and the belt are not only inspected from the side view, but all from a bottom view. Furthermore, when anomalies are detected during the inspection, the sensor structure  124  can automatically perform additional measurements by viewing the problem area from additional angles and/or using additional sensors such as the acoustic sensor, or other sensors. 
         [0043]    Other features of the embodiments can include: 
         [0044]    recording of the sensor data for later evaluation, visual and near infrared videos may be used for inspection of the belt while thermal videos may be used to detect failing roller bearings, 
         [0045]    using the signal strength information from the wireless receivers placed along the conveyor to identify the position of the sensors 
         [0046]    correlating the recording time with the position of roller set  24  that the vehicle has passed, 
         [0047]    evaluating of recorded data and automatically create a report, with the report indicating those roller  12 ,  12 ′ that have abnormally high temperature, 
         [0048]    the report shows which rollers 1) have to be observed, 2) have to be replaced in near future, 3) have to be replaced immediately, 
         [0049]    the report or evaluation anticipates which roller is likely to fail within a certain period of time, and 
         [0050]    creating of history data about each roller from subsequent inspection tours. 
         [0051]    The foregoing preferred embodiments have been shown and described for the purposes of illustrating the structural and functional principles of the present invention, as well as illustrating the methods of employing the preferred embodiments and are subject to change without departing from such principles. Therefore, this invention includes all modifications encompassed within the spirit of the following claims.