Dynamic Adjustment of Wrap Force Parameter Responsive to Monitored Wrap Force and/or For Film Break Reduction

Abstract

A method, apparatus and program product monitor a wrap force during a wrap cycle to dynamically control the dispense rate of a packaging material dispenser to meet a desired containment force to be applied to a load. A conversion may be performed between wrap force and containment force for the monitored wrap force or a containment force parameter to facilitate the performance of a comparison between the monitored wrap force and a containment force parameter associated with the desired containment force to be applied to the load. A wrap force parameter may also be dynamically adjusted, and in some instances, the dynamic adjustment may be responsive to monitored wrap force, and may be used to meet a load containment force requirement for a load. In other instances, the dynamic adjustment may be responsive to monitored packaging material breaks to reduce the occurrence of packaging material breaks.

What is claimed is: 
     
         1 . A method of controlling a load wrapping apparatus of the type configured to wrap a load on a load support with packaging material dispensed from a packaging material dispenser through relative rotation between the packaging material dispenser and the load support, the method comprising:
 prior to initiating a wrap cycle, determining a number of layers of packaging material to be applied to the load during the wrap cycle;   initiating the wrap cycle to begin to wrap the load with packaging material dispensed from the packaging material dispenser during relative rotation between the packaging material dispenser and the load support;   after initiating the wrap cycle, dynamically modifying the determined number of layers of packaging material to be applied to the load during the wrap cycle; and   completing the wrap cycle by wrapping the load with the modified number of layers of packaging material.   
     
     
         2 . The method of  claim 1 , further comprising determining a desired load containment force requirement to be used when wrapping the load with packaging material, wherein determining the number of layers includes determining the number of layers to meet the desired load containment force requirement when wrapping the load with packaging material, and wherein dynamically modifying the determined number of layers substantially maintains the desired load containment force requirement. 
     
     
         3 . The method of  claim 2 , further comprising, during the wrap cycle: monitoring a wrap force applied to the load by the packaging material during the relative rotation;
 performing a comparison between the monitored wrap force and the containment force parameter after a conversion between wrap force and containment force is performed for the monitored wrap force or the containment force parameter; and   dynamically controlling the dispense rate of the packaging material dispenser during the wrap cycle based on the comparison between the monitored wrap force and the containment force parameter.   
     
     
         4 . The method of  claim 3 , wherein the containment force parameter comprises a desired incremental containment force to be applied to the load by each layer of packaging material to meet a containment force requirement for the load. 
     
     
         5 . The method of  claim 4 , further comprising performing the conversion between wrap force and containment force by converting the monitored wrap force to a monitored incremental containment force, wherein performing the comparison includes comparing the monitored incremental containment force to the desired incremental containment force. 
     
     
         6 . The method of  claim 4 , further comprising performing the conversion between wrap force and containment force by converting the desired incremental containment force to a desired wrap force, wherein performing the comparison includes comparing the monitored wrap force to the desired wrap force. 
     
     
         7 . The method of  claim 3 , wherein dynamically controlling the dispense rate of the packaging material dispenser during the wrap cycle includes:
 controlling the dispense rate of the packaging material dispenser during the relative rotation based at least in part on a wrap force parameter; and   dynamically and automatically adjusting the wrap force parameter based on the comparison between the monitored wrap force and the containment force parameter.   
     
     
         8 . The method of  claim 7 , wherein dynamically modifying the determined number of layers of packaging material is performed to maintain the desired containment force in response to adjusting the wrap force parameter. 
     
     
         9 . An apparatus for wrapping a load supported by a load support with packaging material, the apparatus comprising:
 a packaging material dispenser for dispensing packaging material to the load, wherein the packaging material dispenser and the load support are adapted for rotation relative to one other; and   one or more processors configured to perform the method of  claim 1 .