Wrapping apparatus employing stretching film with improved retaining device

Abstract

A wrapping apparatus employing plastic stretching film for items to be wrapped has entry lines and exit lines, which define a horizontal feeding line, in the proximity of a wrapping station (W) provided with a drive ring apt to bring into rotation a reel of the stretching film around the feeding line, and a holding gripper apt to temporarily hold an initial edge of said film in a starting step of the rotation of said reel. A temporary retaining device of said film provided with an elongated hollow member arranged with the longitudinal axis thereof parallel to the feeding line and having an inner side.

What is claimed is: 
     
         1 . A wrapping apparatus employing stretching plastic film for items to be wrapped, comprising an entry line ( 1   a ) and an exit line, which define a horizontal feeding line, having an enter path to and an exit path from a wrapping station (W) provided with a drive ring apt to bring in rotation a reel of said stretching film around said horizontal feeding line, and a holding gripper apt to temporarily hold an initial edge of said film in a starting step of the rotation of said reel, further comprising a temporary retaining device of said film including a stationary hollow elongated suction member arranged with a longitudinal axis thereof parallel to said exit path and having an inner longitudinal side located so as to end up just opposite an item to be wrapped during the permanence in the wrapping station (W), and an outer longitudinal side provided with at least an air suction intake. 
     
     
         2 . The apparatus as claimed in  claim 1 , wherein the hollow elongated member has a flattened transversal section and has a single intake in the shape of an elongated slit. 
     
     
         3 . The apparatus as claimed in  claim 2 , wherein a net having small mesh is laid on the inner side of the hollow member covering the slit. 
     
     
         4 . The apparatus as claimed in  claim 1 , wherein the elongated hollow member is mounted cantilevered on a small support frame fastened upstream of said drive ring. 
     
     
         5 . The apparatus as claimed in  claim 4 , wherein the position of the elongated hollow member, with respect to the feeding line, is adjustable. 
     
     
         6 . The apparatus as claimed in  claim 4 , wherein the elongated hollow member is arranged on the side of the feeding line which is closest to the holding gripper with respect to the movement direction of the reel. 
     
     
         7 . A wrapping method for wrapping items employing stretching plastic film, comprising:
 moving an item along an horizontal feeding line having an entry line and an exit line, having an enter path to and an exit path from a wrapping station (W) provided with a drive ring apt to bring in rotation a reel of said stretching film around said horizontal feeding line, driving a holding gripper to temporarily hold an initial edge of said film in a starting step of the rotation of said reel,   providing a temporary retaining device of said film including a stationary hollow elongated suction member arranged with a longitudinal axis thereof parallel to said exit path and having an inner longitudinal side located just opposite and brushing the item to be wrapped during the permanence in the wrapping station (W), applying vacuum from an air suction intake provided on an outer longitudinal side of said hollow suction member so as to keep said plastic film adjacent to said outer longitudinal side of the hollow member, and   releasing said initial edge of film and withdrawing said holding gripper before said reel has completed one single coil of stretching film around said horizontal feeding line.