Unwrapping apparatus and method for unwrapping articles

Abstract

An unwrapping apparatus, configured to unwrap a stack of wrapped articles, including an unwrapper head, which includes a housing, a cutter head, a drive, wherein the drive is configured to rotate the cutter head relative to the housing. The cutter head includes a gripper, a knife, and an actuator, configured to move the gripper along a path of movement relative to the housing, between a retracted position and an advanced position. The unwrapping apparatus further including a robotic manipulator arm, configured to move the unwrapper head, a registration device, configured to register a contour of the stack, and a controller, configured to control the robotic manipulator arm and the drive, in accordance with the registered contour.

1 . An unwrapping apparatus, configured to unwrap a stack of wrapped articles, comprising:
 an unwrapper head comprising:
 a housing; 
 a cutter head; 
 a drive, wherein said drive is configured to rotate said cutter head relative to said housing; 
 wherein said cutter head comprises:
 a wrapping gripper; 
 a knife; and 
 an actuator configured to move said wrapping gripper along a path of movement relative to said housing between a retracted position and an advanced position; 
 
   a robotic manipulator arm configured to move said unwrapper head;   a registration device configured to register a contour of said stack; and   a controller configured to control said robotic manipulator arm and said drive in accordance with said contour, and said controller further being configured to control said actuator.   
     
     
         2 . The unwrapping apparatus according to  claim 1 , wherein said unwrapper head further comprises:
 a second actuator configured to move said gripper and said knife along a second path of movement relative to said housing between a second retracted position and a second advanced position, wherein said path of movement and said second path of movement are not parallel to one another, and wherein said controller further controls said second actuator; and   a suction channel having a suction inlet at said knife, wherein said second retracted position is closer to said suction channel than said second advanced position.   
     
     
         3 . The unwrapping apparatus according to  claim 1 , wherein said actuator and said wrapping gripper are linked to each other by a pivoting lever, and wherein said actuator acts on one end of said pivoting lever and said wrapping gripper is arranged on another end of said pivoting lever. 
     
     
         4 . The unwrapping apparatus according to  claim 1 , wherein said unwrapper head comprises a spring configured to bias said wrapper gripper towards said advanced position, and wherein said actuator is configured to counteract said spring and move said wrapper gripper towards said retracted position, when activated. 
     
     
         5 . The unwrapping apparatus according to  claim 1 , wherein said registration device comprises one of the following:
 a camera, a scanner, or a device for registering rotation of wheels arranged on said unwrapper heady; or   a device for registering a force resisting movement of said robotic manipulator arm; or   sensors configured to detect distances; or   a combination of two or more of the above mentioned registering options.   
     
     
         6 . A method for unwrapping a stack of articles with a wrapping using an unwrapping apparatus, said unwrapping apparatus comprising:
 an unwrapper head comprising:
 a wrapping gripper selected from the group consisting of: i) a wrapping gripper comprising an arm with a free end for wrapping gripping; and ii) a wrapping gripper with suction inlets for gripping a wrapping by applying suction to said wrapping; and 
 a knife; 
   
       wherein said unwrapping apparatus further comprises:
 a robotic manipulator arm, configured to move said unwrapper heady, 
 a registration device configured to register a contour of said stack; and 
 a controller, configured to control said robotic manipulator arm, said method comprising:
 registering said contour of said stack using said registration device; 
 determining a cutting path which follows said contour of said stack; and 
 moving said unwrapper head to a top surface portion of said stack; 
 gripping by said wrapping gripper a free end edge of said wrapping of said stack at said top surface portion; 
 dragging by said wrapping gripper said free end edge of said wrap towards an edge of said top surface portion; and 
 cutting said wrapping along said cutting path by moving said unwrapper head. 
 
 
     
     
         7 . The method according to  claim 6 , wherein said registering of said contour of said stack by said registering device, comprises one of the following processes:
 recording one or more images using a camera or a scanner; or   counting a number of rotations of wheels arranged on said unwrapper head and contacting said stack during movement of said cutter head to said top surface portion; or   using sensors sensing, during movement of said unwrapper head along said contour, a presence of obstacles or measuring distance; or   measuring, during said moving of said unwrapper head to said top surface portion, loads resisting movement of said robotic manipulator arm; or   a combination of two or more of the above mentioned processes.   
     
     
         8 . The method according to  claim 6 , wherein said registering of said contour of said stack by said registering device, comprises:
 moving said unwrapper head in a horizontal direction towards a portion of said stack of articles until a force is measured resisting a further movement of said unwrapper head in said horizontal direction or an obstacle is detected using sensors;   moving said unwrapper head in a vertical direction, until either:
 1) an edge is detected by registering an absence of a force resisting a further movement in said vertical direction, or using sensors detecting an absence of an obstacle; or 
 2) a corner is detected by measuring a presence of a force resisting a further movement in said vertical direction, or using sensors detecting a presence of an obstacle; and 
 moving said unwrapper head in said horizontal direction; 
 repeating the above mentioned processes until a free end edge of said wrapping is detected; and 
 sending location information of change in directions of movements of said unwrapper head and a location of said free end edge of said wrapping from said registering device to said controller, while conducting the above mentioned processes of registering said contour of said stack. 
   
     
     
         9 . The method according to  claim 6 , wherein the method comprises:
 using a spring to bias said wrapping gripper towards an advanced position relative to a housing comprising said unwrapper head along a path of movement; and   using an actuator to apply a load on one end of a lever connecting said actuator with said wrapping gripper to counteract a pressing force of said spring and moving said wrapping gripper towards a first retracted position along said path of movement.   
     
     
         10 . The method according to  claim 9 , comprising moving said wrapping gripper and said knife between a second retracted position and a second advanced position along a second path of movement using a second actuator, wherein said first path and said second path of movement are not parallel to one another. 
     
     
         11 . The method according to  claim 9  comprising:
 arranging said unwrapper head at a surface of said wrapping; 
 retracting said wrapping gripper towards said retracted position; 
 pulling a portion of said wrapping, using suction, towards a suction inlet of a suction channel comprised in said unwrapper head; and 
 piercing said portion of said wrapping being pulled towards said suction inlet using said knife arranged at said suction inlet. 
 
     
     
         12 . A method for unwrapping a stack of wrapped articles using an unwrapping apparatus comprising:
 an unwrapper head comprising:
 a housing; 
 a cutter head; 
 a drive, wherein said drive is configured to rotate said cutter head relative to said housing; 
 wherein said cutter head comprises:
 a wrapping gripper; 
 a knife; and 
 an actuator configured to move said wrapping gripper along a path of movement relative to said housing between a retracted position and an advanced position; 
 
   a robotic manipulator arm configured to move said unwrapper head;   a registration device configured to register a contour of said stack; and   a controller configured to control said robotic manipulator arm and said drive in accordance with said contour, and said controller further being configured to control said actuator;   said method comprising:
 registering said contour of said stack using said registration device; 
 determining a cutting path which follows said contour of said stack; 
 moving said cutter head to a top surface portion of said stack; 
 gripping, by said wrapping gripper, a free end edge of a wrapping of said stack at said top surface portion; 
 dragging, by said wrapping gripper, said free end edge of said wrapping towards an edge of said top surface portion; and 
 initiating a cutting of said wrapping along said cutting path while dragging uncut portions of said wrapping downwards along said cutting path. 
   
     
     
         13 . The unwrapping apparatus according to  claim 1 , wherein said wrapping gripper is in the form of an arm with a free end defining a gripping tip. 
     
     
         14 . The method according to  claim 6 , wherein said wrapping gripper with suction inlets is rotatably mounted to a housing of said unwrapper head. 
     
     
         15 . The method according to  claim 6 , wherein said gripping by said wrapping gripper a free end edge of said wrapping of said stack at said top surface portion is performed by applying suction by said wrapping gripper to said wrapping at said free end edge.