Abstract:
A load monitoring system for a lifting system that includes a lifting device is provided. The load monitoring system includes a lifting link assembly and a controller. The lifting link assembly includes a link body, a strain sensor, and a radio frequency identification (RFID) device. The link body is structured and arranged to couple the lifting device to a load. The strain sensor is fixed to the link body and is configured to generate a signal corresponding to the load. The RFID device is fixed to the link body and is configured to receive the signal. Further, the controller is in communication with the RFID device, and is configured to receive the signal from the RFID device and initiate a safe lifting protocol in response to the signal attaining a pre-determined threshold value.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to lifting systems. More particularly, the present disclosure relates to a load monitoring system for a lifting system. 
       BACKGROUND 
       [0002]    During a manufacturing process, a product is typically advanced through a plurality of manufacturing stations within a manufacturing chain. Specifically, the product is transported through each of the manufacturing stations along a transportation system. The transportation systems may include overhead cranes, which are designed to lift and transport loads, within or between manufacturing stations. Overhead cranes, particularly those of the larger type, most commonly embody a bridge girder supported on trucks. The trucks are movable over runway beams supported on columns. In addition, the overhead crane includes one or more lifting components structured to lift loads for transportation. The lifting component, such as hook, strap, magnet, and/or the like, is coupled to a trolley frame slidably mounted on the bridge girder. Such lifting components may have rated capacities for a favorable lift operation. Further, during the lift operation, the lifting components may be subjected to stresses due to the loads being lifted by the lifting components. It may be considered that during the lift operation, the strain caused upon the lifting component, due to the lifted loads, may exceed a pre-determined threshold value. Since, the hoist devices have rated capacities, lifting the loads beyond the rated capacities may impose considerable stress on the lifting component and may result in unfavorable consequences. 
         [0003]    U.S. Publication No. 2010/0044332 discloses a method to monitor overstress conditions experienced by a crane component. In the overstress condition, a wireless signal that indicates an overstress condition is generated. In response to receipt of the wireless signal, a record of the overstress condition is stored in a storage module mechanically coupled with a crane component. However, the reference does not discuss a provision for an active overstress prevention based on rated capacities of lifting components. 
       SUMMARY OF THE INVENTION 
       [0004]    The present disclosure relates to a load monitoring system for a lifting system. The lifting device is configured to lift a load during a lifting operation. 
         [0005]    In accordance with the present disclosure, the load monitoring system includes a lifting link assembly and a controller. The lifting link assembly includes a link body, a strain sensor, and a radio frequency identification (RFID) device. The link body is structured and arranged to couple the lifting device to the load. The strain sensor is fixed to the link body and is configured to generate a signal corresponding to the load. The RFID device is fixed to the link body and is configured to receive the signal. Further, the controller is in communication with the RFID device, and is configured to receive the signal from the RFID device and initiate a safe lifting protocol in response to the signal attaining a pre-determined threshold value. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective view of a lifting system engaged with a load, in accordance with the concepts of the present disclosure; 
           [0007]      FIG. 2  is a schematic view of a view of a first embodiment of a lifting link assembly of the lifting system of  FIG. 1 , illustrating a strain sensor and an RFID device in an enlarged view of the encircled area of an adhesive layer on the lifting link assembly, in accordance with the concepts of the present disclosure; 
           [0008]      FIG. 3   a  is a perspective view of a second embodiment of a lifting link assembly for use within the lifting system of  FIG. 1 , which is embedded with a strain sensor and an RFID device, in accordance with the concepts of the present disclosure; 
           [0009]      FIG. 3   b  is a perspective view of a third embodiment of a lifting link assembly for use within the lifting system of  FIG. 1 , which is embedded with a strain sensor and an RFID device, which are illustrated by a cut-out, in accordance with the concepts of the present disclosure; 
           [0010]      FIG. 3   c  is a perspective view of a fourth embodiment of a lifting link assembly for use within the lifting system of  FIG. 1 , which is embedded with a strain sensor and an RFID device, which are illustrated by a cut-out, in accordance with the concepts of the present disclosure; 
           [0011]      FIG. 4  is a perspective view of a fifth embodiment of a lifting link assembly with a lifting eye embedded with the strain sensor and the RFID device illustrating a strain sensor and an RFID device in an enlarged view of the encircled area of the lifting eye of the lifting link assembly, in accordance with the concepts of the present disclosure; and 
           [0012]      FIG. 5  is a block diagram of a load monitoring system for the lifting system of  FIG. 1 , in accordance with the concepts of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    Referring to  FIG. 1 , there is shown a lifting system  100 . The lifting system  100  may include a plurality of lifting link assemblies  102  mounted to a lifting device  104 . The plurality of lifting link assemblies  102  includes the lifting link assembly  102 ′ and the lifting link assembly  102 ″. The lifting device  104  may include a pair of runway beams  106 , a pair of trucks  108 , an idler girder  110 , a trolley frame  112 , a pair of bridge drives  114 , and a pair of trolley drives  116  as is customary. The runway beams  106  may be supported on columns that may be independent of, attached to, and/or integral with the building columns of a manufacturing facility (not shown). The runway beam  106  includes a first end  118  and second end  120 , which defines a runway rail  122 . The runway rail  122  is structured to allow the pair of trucks  108  to slide between the first end  118  and the second end  120 . Each truck  108  includes the bridge drive  114  to facilitate synchronization of sliding of the truck  108 . 
         [0014]    The idler girder  110  is attached between the pair of the trucks  108 . The idler girder  110  includes a first end  124  and a second end  126 , which defines a bridge rail  128 . The first end  124  and the second end  126  include a plurality of end stops  130 . Further, the bridge rail  128  is structured to facilitate slidable movement of the trolley frame  112 . The movement of the trolley frame  112  may slide over the bridge rail  128 ; however, such movement of the trolley frame  112  is restricted by the end stops  130  placed at the first end  124  and the second end  126 . The trolley frame  112  includes a hoist  132  and the pair of trolley drives  116 . The trolley drives  116  on each side of the trolley frame  112  facilitate the slidable movement of the trolley frame  112  over the bridge rail  128  between the first end  124  and the second end  126  of the idler girder  110 . 
         [0015]    Further, the lifting device  104  may be coupled to a hook  134 , via the lifting link assembly  102 ′. The lifting link assembly  102 ′ may be a strap, cord or chain member, for example, or any portion of the aforesaid hereof, fitted with a force sensing and communication componentry as will be described herein below. Further, as seen in  FIG. 1 , the hook  134  carries a load  136 , such as a partially assembled transmission for transit to an adjacent build station, for example, via the lifting link assembly  102 ″, which is tied around the load  136 . The lifting link assembly  102 ″ facilitates engagement with the lifting device  104  and transmits the weight of the load  136  to the lifting device  104 . The lifting link assembly  102 ′ may be connected in series, with at least one of the lifting link assemblies  102 ″,  102 ″′,  102 ″″, and  102 ″″ (as shown in  FIGS. 2-4 ). In exemplary embodiments, the lifting link assembly  102 ′ includes a link body  200 ′, in the form of a chain link (as shown in  FIG. 2 ). The lifting link assemblies  102 ″,  102 ″′,  102 ″″ include respective link bodies  200 ″,  200 ″′,  200 ″″, which may be straps (as shown in  FIGS. 3   a ,  3   b , and  3   c ). Alternatively, the lifting link assembly  102 ″″′ includes a link body  200 ″″′, which may be in the form of a lifting lug (as shown in  FIG. 4 ). 
         [0016]    Referring to  FIG. 2 , there is shown the lifting link assembly  102 ′ having a link body  200 ′. The lifting link assembly  102 ′ is structured to have a strain sensor  202  and an RFID device  204  fixed thereto. The strain sensor  202  and the RFID device  204  may be fixed to the lifting link assembly  102 ′, via an adhesive or glue, as is customary. As illustrated in  FIG. 2 , an adhesive layer  206  is applied on the link body  200 ′, to facilitate attachment of the strain sensor  202  and the RFID device  204 . An enlarged view of an encircled portion of the adhesive layer  206  is depicted to illustrate the strain sensor  202  and the RFID device  204 . The strain sensor  202  is placed on the lifting link assembly  102 ′ to measure the strain generated in the lifting link assembly  102 ′, while the load  136  (shown in  FIG. 1 ) is lifted during a lift operation. The strain sensor  202  generates a signal that corresponds to the strain in the lifting link assembly  102 ′, which in turn corresponds to the weight of the load  136  (shown in  FIG. 1 ). The strain sensor  202  is coupled to the RFID device  204 , which is adapted to receive the signal from the strain sensor  202 , and thus, communicate with the lifting device  104 . 
         [0017]    Referring to  FIG. 3   a , there is shown a second embodiment of the lifting link assembly  102 ″. The lifting link assembly  102 ″ may be positioned in series with the lifting link assembly  102 ′. The lifting link assembly  102 ″ includes a link body  200 ″, which is a single length of high tension material, such as a nylon composite, for example. The strain sensor  202  and the RFID device  204  may be embedded in the link body  200 ″ to ensure stretch or deflection of the lifting link assembly  102 ″. The strain sensor  202  generates a signal corresponding to a strain experienced by the lifting link assembly  102 ″, while the object is lifted. 
         [0018]    Referring to  FIG. 3   b , there is shown a third embodiment of the lifting link assembly  102 ″′. The lifting link assembly  102 ′″ may be positioned in series with the lifting link assembly  102 ′. The lifting link assembly  102 ″′ includes a link body  200 ′″, which is a strap having an eye and eye structure. The link body  200 ″′ is composed of high tension material, such as a nylon composite, for example. The strain sensor  202  and the RFID device  204  may be embedded in the link body  200 ″′ to ensure stretch or deflection of the lifting link assembly  102 ″′. The strain sensor  202  generates the signal corresponding to the strain experienced by the lifting link assembly  102 ″′ while the object is lifted. 
         [0019]    Referring to  FIG. 3   c , there is shown a fourth embodiment of the lifting link assembly  102 ″″. The lifting link assembly  102 ″″ may be positioned in series with the lifting link assembly  102 ′. The lifting link assembly  102 ″″ includes a link body  200 ″″, which is a strap having unilink structure. The link body  200 ″″ is composed of high tension material, such as a nylon composite, for example. The strain sensor  202  and the RFID device  204  may be embedded in the link body  200 ″″ to ensure stretch or deflection of the lifting link assembly  102 ″″. The strain sensor  202  generates the signal corresponding to the strain experienced by the lifting link assembly  102 ″″ while the object is lifted. 
         [0020]    The strain sensor  202  is in communication with the RFID device  204 . The strain measured by the strain sensor  202  is wirelessly communicated to a controller (shown as  502  in  FIG. 5 ) to effect a safe lift protocol for the lifting device  104  via the RFID device  204 . A safe lift protocol may be one of halting any further movement of the load  136  (shown in  FIG. 1 ) and an operator alert, for example. 
         [0021]    Referring to  FIG. 4 , there is shown a fifth embodiment of the lifting link assembly  102 ″″′, which is a magnet assembly. The lifting link assembly  102 ″″′ may include the link body  200 ″″″ and a lifting eye  400 , which is coupled to the strain sensor  202  and the RFID device  204 , via the adhesive layer  206 ′. The strain sensor  202  may measure the load  136  (shown in  FIG. 1 ) experienced by the lifting link assembly  102 ″″′ while performing the lift operation. Since, the strain sensor  202  is in control communication with the RFID device  204 , the strain measured by the strain sensor  202  is communicated to the lifting device  104 , via the RFID device  204 . 
         [0022]    Referring to  FIG. 5 , there is shown a block diagram of a load monitoring system  500  for the lifting system  100 . The load monitoring system  500  may include a controller  502 , a display  504 , the strain sensor  202 , and the RFID device  204 . The controller  502  may be located on the lifting device  104 . The controller  502  may be adapted to monitor the lift operation, based on the communication with the lifting link assembly  102 , via the strain sensor  202  and the RFID device  204 . The controller  502  may be coupled to the display  504 , which is positioned in the lifting device  104 . The display  504  may be a graphical user interface, a touch screen, and/or the like. 
       INDUSTRIAL APPLICABILITY 
       [0023]    In operation, during the lift operation, the load  136  is engaged with the lifting link assembly  102 , which includes the strain sensor  202  and the RFID device  204 . As the lifting device  104  lifts the load  136  off a rest position, the strain sensor  202  in the lifting link assembly  102  stretches in length. By this means, there is an increase in electrical resistance. This results in generation of the signal that corresponds to the strain experienced by the strain sensor  202 . The signal thus generated is communicated to the RFID device  204 , which is connected to the strain sensor  202 . The RFID device  204  then sends the signal to the controller  502 . The controller  502  infers the strain information, which is based on the signal and determines if the measured strain is equal to the pre-determined threshold value for the respective lifting link assembly  102 . The pre-determined threshold value corresponds to the strain beyond which the lifting link assembly  102  may fail. Thus, upon determination that the strain in the strain sensor  202  of the lifting link assembly  102  has reached the pre-determined threshold value, the controller  502  initiates a safe lifting protocol and sends signals to the lifting device  104  to disable or stop the lift operation. The controller  502  also sends alert signals to the display  504  for operator information. The display  504  is adapted to visually represent data that pertains to the lift operation received by the controller  502 . The alert signal may be accompanied with sound alerts. In an embodiment, the controller  502  disables all navigation functions, except for the function that lowers the load  136 . 
         [0024]    For example, the lifting system  100  includes the lifting link assembly  102 ′ and  102 ″. In such case, the lifting link assembly  102 ″ may fail at a lower load as compared to the lifting link assembly  102 ′. This implies that the pre-determined threshold value for the lifting link assembly  102 ″ is lower than the pre-determined threshold value of the lifting link assembly  102 ′. Thus, in this case, the controller  502  gives priority to a lower pre-determined threshold value. The lower pre-determined threshold value corresponds to the pre-determined threshold value of lifting link assembly  102 ″. This helps in prevention of the failure of the lifting link assembly  102 ″, while lifting the load  136 . This way failure of the weakest lifting link assembly  102  is prevented. In an embodiment, the RFID device  204  is coupled to loads, fixtures, pallets, and actual parts involved in the lift operation. In such case, an RFID reader is employed to extract information regarding the weight of the loads, fixtures, pallets, and/or actual parts (such as clamping/holding devices) and pre-determined threshold strain value for each of the loads, fixtures, pallets, and/or actual parts. Further, this may indicate whether the loads, fixtures, pallets, actual parts, and/or the current lifting link assembly  102  are favorable for the lift, which prevents any unfavorable results. Accordingly, the load monitoring system  500  notifies the operator about the lift operation via the display  504 . This implies that the load monitoring system  500  notifies the operator if all conditions are optimum for the lift operation or what units need to be replaced to complete the lift operation, for example, if the lifting link assembly  102  does not meet weight limits or the load exceeds limit for the lifting device  104 . The proposed load monitoring system  500  intends to provide a real-time monitoring of the load  136  to increase productivity of the lift operations. The disclosed load monitoring system  500  makes use of strain sensors which provides information of stresses in the lifting link assemblies  102 . On reaching, the pre-determined threshold strain value, the disclosed system stops the raising of the lifting link assembly  102 , thereby halting the lift operation. The existing systems calculate favorable total lift weight based on weight of each object to be lifted. 
         [0025]    The many features and advantages of the disclosure are apparent from the detailed specification, and, thus, it is intended by the appended claims to cover all such features and advantages of the disclosure, which fall within the true spirit and scope thereof. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the disclosure to the exact construction and operation illustrated and described, and, accordingly, all suitable modifications and equivalents may be resorted to that fall within the scope of the disclosure.