Method and a unit for feeding elements of sheet material to a product wrapping line

Abstract

Coupons are fed from a supply station to an assembly station forming part of a wrapping line, where they are associated each with a relative product. The coupons are engaged along one vertical edge by the lugs of a looped conveyor belt, pushed a set distance along a transfer line sliding internally of a guide channel, and released by the belt only after entering the assembly station, where the single coupon comes to rest interposed between a product and a relative wrapper blank.

What is claimed  
     
         1 ) a method for feeding elements of sheet material to a product wrapping line, wherein the elements of sheet material are conveyed from a supply station to an assembly station and united with relative products, including at least a step of pushing the elements of sheet material along a predetermined transfer line and through a predetermined distance into the assembly station.  
     
     
         2 ) A method as in  claim 1 , wherein the pushing step comprises a step of intercepting and engaging in contact with the element of sheet material along a first edge substantially perpendicular to the transfer line, a pushing step during which contact is maintained with a predetermined area of the first edge, and a release step during which contact with the first edge ceases.  
     
     
         3 ) A method as in  claim 2 , wherein the pushing step is brought about by maintaining contact between the predetermined area of the first edge of the element of sheet material, and relative pushing means.  
     
     
         4 ) A method as in  claim 2 , wherein the pushing step, at least, occurs along a guide channel extending along the transfer line, presenting a bottom track disposed substantially parallel to the transfer line and offered to a second edge of the element of sheet material, and two restraining side walls.  
     
     
         5 ) A method as in  claim 4 , comprising a step of feeding the elements of sheet material from a supply, coinciding with the supply station, to the infeed end of the channel, wherein the feeding step comprises a final step of taking up the element of sheet material and inserting it into the channel, thereby ensuring that each successive element of sheet material can be positioned within the channel.  
     
     
         6 ) A method as in  claim 5 , wherein the step of feeding elements of sheet material from the supply to the infeed end of the channel involves a first rotational movement about an axis lying remote from the plane occupied by the element of sheet material, and a second rotational movement simultaneous with the first about an axis lying in close proximity to the selfsame plane.  
     
     
         7 ) A method as in  claims 1  to  6 , comprising a step, occurring on completion of the pushing step and at a point coinciding with the assembly station, of interposing each element of sheet material between a product and a respective wrapper blank.  
     
     
         8 ) A method as in  claim 7 , comprising a step in which the assembly composed of the product, the relative element of sheet material and a corresponding wrapper blank, is pushed along a path extending transversely to the predetermined transfer line to the end of bringing about a folding and wrapping operation.  
     
     
         9 ) A method as in  claims 1  to  8 , wherein the timing of the pushing step is predetermined and coordinated with that of the steps by which the elements of sheet material are fed, picked up and inserted into the channel.  
     
     
         10 ) A unit for feeding elements of sheet material to a product wrapping line, by which the elements of sheet material are conveyed from a supply station to an assembly station and united with relative products, comprising pushing means such as will direct the elements of sheet material along a predetermined transfer line and through a predetermined distance into the assembly station.  
     
     
         11 ) A unit as in  claim 10 , wherein pushing means comprise relative pushing elements capable of movement occurring cyclically between a position of interception and contact with a first edge of the element of sheet material substantially perpendicular to the transfer line, and a release position at which contact with the first edge ceases, along the transfer line.  
     
     
         12 ) A unit as  claim 11 , wherein pushing means comprise conveyor means capable of movement along forward and return legs of a closed path of which the forward leg extends substantially along the transfer line.  
     
     
         13 ) A unit as in  claim 12 , wherein conveyor means comprise a belt looped around two pulleys, of which one is power driven, and furnished with a plurality of equispaced projections constituting the pushing elements.  
     
     
         14 ) A unit as in  claim 13 , wherein conveyor means comprise a guide channel extending along the transfer line and presenting a section of “U” profile composed of two restraining side walls and a bottom track disposed substantially parallel to the transfer line, of which the track is offered to a second edge of the element of sheet material, and at least one of the side walls presents a longitudinal slot affording a passage to the pushing elements.  
     
     
         15 ) A unit as in  claims 10  to  14 , comprising feed means, associated with the assembly station, by which successive wrapper blanks are directed along a feed path transverse to the transfer line and positioned in a plane substantially parallel to the plane occupied by the element of sheet material, also a pusher device, positioned to engage a product occupying the assembly station and capable of reciprocating movement along a path transverse to the plane occupied by the wrapper blanks, wherein the element of sheet material is interposed between a respective product and a respective wrapper blank at the assembly station.  
     
     
         16 ) A unit as in  claim 15 , comprising reaction means located along the path followed by the pusher device, of which the function is to perform a folding operation.  
     
     
         17 ) A unit as in  claim 14 , comprising feed means by which the elements of sheet material are conveyed from a supply to the infeed end of the channel.  
     
     
         18 ) A unit as in  claim 17 , wherein feed means comprise a rocking arm pivotable about a first axis of rotation substantially parallel to the transfer line, of which the free end carries holder means pivotable about a second axis of rotation parallel to the first axis.  
     
     
         19 ) A unit as in  claim 18 , wherein the rocking arm is caused to pivot about the first axis in a direction opposite to the direction in which the holder means are caused to pivot about the second axis.  
     
     
         20 ) A unit as in  claim 18 , wherein feed means comprise take-up and insertion means by which the element of sheet material is transferred from the holder means into the channel.  
     
     
         21 ) A unit as in  claim 20 , wherein the take-up and insertion means comprise rollers by which the element of sheet material is gripped and positioned in the channel.