Conveyor system and method for accumulating packages of varying lengths

Abstract

A drive controller for controlling movement of a plurality of packages by an accumulation conveyor. The drive controller is configured to determine a length of each of the packages and to coordinate driving of a number of zones needed to accommodate the package. For example, a sensor in each of the conveyor zones communicates blockage by the packages to the drive controller. The drive controller determines a sequence of blockage of the sensors in adjacent zones. Blockage of the sensor in an upstream zone before the sensor in a downstream zone indicates an oversized package that extends longer than a zone length of the downstream zone and into the upstream zone. The drive controller is configured to drive the downstream zone and upstream zone simultaneously when detecting the oversized package.

1 . An accumulation conveyor for moving packages, the accumulation conveyor comprising:
 a conveying surface divided into a plurality of zones;   a plurality of sensors configured to detect a first package having a first length and a second package having a second length; and   a drive controller configured to:
 determine a first number of the zones needed to accommodate the first length of the first package; 
 in response to determining the first number of the zones, allocating the first number of the zones for moving the first package; 
 coordinate operation of the first number of the zones to move the first package along the conveying surface; 
 determine a second number of the zones needed to accommodate the second length of the second package; 
 in response to determining the second number of the zones, allocating the second number of the zones for moving the second package; and 
 coordinate operation of the second number of zones to move the second package along the conveying surface. 
   
     
     
         2 . The accumulation conveyor system of  claim 1 , wherein the first number of the zones and the second number of the zones are different because the first length and the second length are different. 
     
     
         3 . The accumulation conveyor system of  claim 1 , wherein the first number of the zones and the second number of the zones are equal because the first length and the second length differ by less than a length of one of the zones. 
     
     
         4 . The accumulation conveyor system of  claim 1 , wherein:
 the sensors are configured to detect a third package having a third length; and   in response to the sensors detecting the third package, the drive controller is configured to:
 determine a third number of the zones needed to accommodate the third length of the third package; 
 in response to determining the third number of the zones, allocating the third number of the zones for moving the third package; and 
 coordinate operation of the third number of zones to move the third package along the conveying surface. 
   
     
     
         5 . The accumulation conveyor system of  claim 1 , wherein the first number of zones is one. 
     
     
         6 . The accumulation conveyor system of  claim 1 , wherein the second number of zones is one. 
     
     
         7 . A method of controlling zones of an accumulation conveyor comprising:
 determining a first number of the zones to accommodate a first package, wherein the first number of the zones is based on a first length of the first package;   in response to determining the first number of the zones, allocating the first number of the zones for moving the first package;   coordinating operation of the first number of the zones to move the first package along the accumulation conveyor;   determining a second number of the zones to accommodate a second package, wherein the second number of the zones is based on a second length of the second package;   in response to determining the second number of the zones, allocating the second number of the zones for moving the second package; and   coordinating operation of the second number of the zones to move the second package along the accumulation conveyor.   
     
     
         8 . The accumulation conveyor system of  claim 7  further comprising:
 determining the first length is different than the second length and, in response, the first number of the zones is different than the second number of the zones. 
 
     
     
         9 . The accumulation conveyor system of  claim 7  further comprising:
 determining the first length and the second length differ by less than a length of one of the zones and, in response, the first number of the zones is equal to the second number of the zones. 
 
     
     
         10 . The accumulation conveyor system of  claim 7  further comprising:
 determining a third number of the zones to accommodate a third package, wherein the third number of the zones is based on a third length of the third package; 
 in response to determining the third number of the zones, allocating the third number of the zones for moving the third package; and 
 coordinating operation of the third number of the zones to move the third package along the accumulation conveyor.