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, wherein the packaging material is dispensed from a roll of packaging material, the method comprising, using one or more processors:
 determining a desired containment force to be applied to loads by the load wrapping apparatus;   controlling a dispense rate of the packaging material dispenser during the relative rotation based at least in part on a wrap force parameter to apply a number of layers of packaging material during the relative rotation based at least in part on a layer parameter, wherein the wrap force parameter and the layer parameter are selected based at least in part upon the determined desired containment force;   detecting a roll change; and   in response to detecting the roll change, self-calibrating the load wrapping apparatus by:
 selecting initial values for the wrap force and layer parameters to apply the determined desired containment force; 
 monitoring wrap force or packaging material breaks over at least a portion of a wrap cycle after selecting the initial values; and 
 dynamically adjusting the wrap force parameter or the layer parameter based upon the monitored wrap force or packaging material breaks. 
   
     
     
         2 . The method of  claim 1 , wherein monitoring wrap force or packaging material breaks over at least a portion of a wrap cycle includes monitoring wrap force, and wherein dynamically adjusting the wrap force parameter or the layer parameter includes dynamically adjusting the wrap force parameter based upon the monitored wrap force in response to determining an unacceptable containment force applied to a load. 
     
     
         3 . The method of  claim 1 , wherein monitoring wrap force or packaging material breaks over at least a portion of a wrap cycle includes monitoring packaging material breaks, and wherein dynamically adjusting the wrap force parameter or the layer parameter includes dynamically adjusting the wrap force parameter based upon the monitored packaging material breaks. 
     
     
         4 . The method of  claim 1 , wherein dynamically adjusting the wrap force parameter or the layer parameter includes:
 dynamically adjusting the wrap force parameter;   determining if the dynamically adjusted wrap force parameter is outside of a wrap force limit; and   dynamically adjusting the layer parameter and the wrap force parameter to meet the desired containment force in response to determining that the dynamically adjusted wrap force parameter is outside of a wrap force limit.   
     
     
         5 . 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 .