Stretch wrapping machine

Abstract

Provided is a stretch wrapping machine that can stably convey film even in a case where, for the purpose of wrapping, a holding component that holds the film is provided separately from belts for conveyance. The stretch wrapping machine is equipped with conveyance devices ( 22 ) having belt conveyance units and belt pressing mechanisms, a clamp device ( 23 ), a wrapping station, and a control device ( 9 ). At the wrapping station, product is pushed against film held by the clamp device ( 23 ), and the product is wrapped by the film. The belt conveyance units have upper belts and lower belts that sandwich end portions of the film. Pressing members ( 221 e ) of the belt pressing mechanisms apply force to the upper belts so that the force with which the upper belts and the lower belts sandwich the film increases. Additionally, the control device ( 9 ) controls the belt pressing mechanisms so that during conveyance of the film the force resulting from the pressing members ( 221 e ) acts on the upper belts and so that after conveyance of the film the force resulting from the pressing members ( 221 e ) that had acted on the upper belts is cancelled.

1 . A stretch wrapping machine comprising:
 a conveyance component that conveys film pulled out from a film roll;   a holding component that holds the film conveyed by the conveyance component;   a wrapping component that pushes a wrapping item against the film held by the holding component and uses the film to wrap the wrapping item; and   a control component that controls the operations of the conveyance component, the holding component, and the wrapping component,   wherein   the conveyance component has
 a first conveyance unit including a first belt and a second belt that sandwich an end portion of the film and 
 a force applying component that applies force to the first belt so that the force with which the first belt and the second belt sandwich the film increases, and 
   the control component controls the force applying component so that during the conveyance of the film by the conveyance component the force resulting from the force applying component acts on the first belt and so that after the conveyance of the film by the conveyance component the force resulting from the force applying component that had acted on the first belt is cancelled.   
     
     
         2 . The stretch wrapping machine according to  claim 1 , wherein after the conveyance of the film by the conveyance component the control component has the holding component hold the film and causes the wrapping by the wrapping component to be carried out in a state in which the force resulting from the force applying component that had acted on the first belt is cancelled. 
     
     
         3 . The stretch wrapping machine according to  claim 1 , wherein
 the holding component has a first holding member in which a first holding surface is formed and a second holding member in which a second holding surface that opposes the first holding surface is formed, and   the first holding member and the second holding member hold the film by sandwiching a section of the film other than the section of the film positioned between the first belt and the second belt.   
     
     
         4 . The stretch wrapping machine according to  claim 3 , wherein
 the force applying component has a pressing member in which a pressing surface that presses the first belt is formed and a drive component that moves the pressing member, and   the area of the pressing surface of the pressing member is smaller than that of the first holding surface of the first holding member.   
     
     
         5 . The stretch wrapping machine according to  claim 1 , wherein
 the first conveyance unit uses the first belt and the second belt to sandwich the end portion which is one end portion of the film and convey the film,   the conveyance component further has a second conveyance unit that uses a third belt and a fourth belt to sandwich another end portion of the film and convey the film,   the stretch wrapping machine further comprises
 a first unit moving component that causes the first conveyance unit to move in a film width direction intersecting a conveyance direction of the film and 
 a second unit moving component that causes the second conveyance unit to move in the film width direction, and 
   in accordance with the width dimension of the film the control component
 controls the first unit moving component to change a first distance which is a distance from one end edge of the film in the one end portion of the film sandwiched by the first belt and the second belt of the first conveyance unit and 
 controls the second unit moving component to change a second distance which is a distance from another end edge of the film in the other end portion of the film sandwiched by the third belt and the fourth belt of the second conveyance unit. 
   
     
     
         6 . The stretch wrapping machine according to  claim 5 , wherein the control component increases the first distance and increases the second distance when the width dimension of the film increases.