Unit and method for feeding folded tissue products or the like in a revolving drum packaging machine

Abstract

An apparatus for packaging stacks of folded paper products such as handkerchiefs or the like with blanks of plastic film, comprising at least one pocket ( 58 ), insertion means ( 5 ), along an insertion direction, of a single stack in said pocket ( 58 ) with the interposition and consequent folding of a corresponding blank, said pocket ( 58 ) being operatively associated with stop means ( 24 ) of the stack completely inserted within said pocket. There are control means ( 22 ) adapted to operate the stop means ( 24 ) in a coordinated manner with respect to the operation of the insertion means ( 5 ), to provide an abutment to the stack during the whole insertion step in the pocket ( 58 ), the stop means ( 24 ) comprising suction means ( 72 ) adapted to keep the film in position and to disengage the same film at least in an extraction step of the stack from the pocket.

1 . A unit for compressing and inserting a sequence of stacks of tissue paper products or the like, from an upstream feeding system to a revolving drum for packaging stacks with blanks of plastic film, said unit comprising insertion means for inserting said stacks in said drum in a radial direction and compression means for compressing the stacks, preliminary to said insertion, in a direction substantially tangential of said drum, wherein said compression means and said insertion means are supported respectively by a lower arm and by an upper arm radially projecting from a rotation axis of said drum and arranged sideways to the same drum, said arms being tiltable in a reciprocating manner, independently one from each other and from the drum, around said axis, driving means being provided for driving, respectively, said insertion means, said compression means and said arms, in a coordinated manner with each other and with the rotation of said drum. 
     
     
         2 . The unit according to  claim 1 , wherein said insertion means comprise an insertion device slidable in a reciprocating manner along said upper arm for pushing said stacks towards said drum, and said compression means comprise a compression device in turn supported slidably and driven in a reciprocation manner along said lower arm, said driving means being adapted to drive the reciprocating motion of said compression device in a coordinated manner with the reciprocating motion of said insertion device, for avoiding mutual interference following to the tilting motion of said arms. 
     
     
         3 . The unit according to  claim 2 , wherein said driving means are adapted to drive said insertion device and said compression device so that said insertion device is adapted to carry out a continuous closed loop motion around at least a portion of said compression device. 
     
     
         4 . The unit according to  claim 2 , wherein said stack insertion device projects towards said drum from a side of said upper arm, arranged externally, and said compression device is supported cantileverly, still towards said drum, by said lower arm, arranged internally, that is close with the same drum, the radial extension of said arms being such that said insertion device and said compression device face a working surface of said drum. 
     
     
         5 . The unit according to  claim 2 , further comprising a front stop plate for stopping the stacks when inserted within said compression device, said front stop plate being reciprocatingly movable, along a direction substantially orthogonal with said lower arm when the same is in a lower dead point, in an independent fashion with respect to the same arm, said plate being supported between the compression device and said drum by a support integral with a basement structure of said unit. 
     
     
         6 . The unit according to  claim 5 , wherein in said lower dead point of said lower arm, corresponding to an insertion phase of said stacks in said compression device, said lower arm is inclined with respect to the horizontal direction, with a descending inclination toward said drum. 
     
     
         7 . The unit according to  claim 5 , wherein said front stop plate is associated with suction means for exerting a holding action of said stacks. 
     
     
         8 . The unit according to  claim 2 , wherein said compression device comprises a lower plate movable in a reciprocating manner in a direction orthogonal with said lower arm, and a top fixed plate integral with said arm, at an adjustable distance therefrom, said insertion device being adapted to pass between said plates. 
     
     
         9 . The unit according to  claim 8 , wherein said lower plate and said top plate are arranged so that a median plane of a stack with respect to its height in the maximum compression within said compression device lies in a diametrical plane of said drum. 
     
     
         10 . The unit according to  claim 1 , wherein said driving means comprise cam means comprising an eccentrically revolving disc, defining a cam surface contacted tangentially at an intermediate point by a crank hinged at an end, thereby a tilting of said crank is driven around the hinge point as a result of the rotation of said disc, the driving means further comprising linking rods for driving the respective devices, said rods being hinged respectively to the devices and to said crank at predetermined points comprised between the disc contacting point and a free end of the crank, opposed to the hinged end. 
     
     
         11 . The unit according to  claim 8 , wherein said driving means comprise cam means comprising an eccentrically revolving disc, defining a cam surface contacted tangentially at an intermediate point by a crank hinged at an end, thereby a tilting of said crank is driven around the hinge point as a result of the rotation of said disc, the driving means further comprising linking rods for driving the respective devices, said rods being hinged respectively to the devices and to said crank at predetermined points comprised between the disc contacting point and a free end of the crank, opposed to the hinged end. 
     
     
         12 . The unit according to  claim 11 , wherein said driving means comprise a multiple cam upper driving device adapted to control an upper crank and rod device for radially driving said insertion device, and a further upper crank and rod device for radially driving said compression device, said driving means further comprising a lower multiple cam driving device adapted to control a first lower crank and rod device for driving said lower compression plate, a second lower rod and crank device for driving said front stop plate of the stacks, a third lower rod and crank device for driving the rotation of said lower tilting arm, and a fourth lower rod and crank device for driving the rotation of said upper tilting arm. 
     
     
         13 . A compression and insertion method for inserting a stack of folded products by means of a unit according to  claim 1 , comprising the following steps:
 inserting a stack in said compression device with said lower arm in a lower dead end position;   lifting said lower arm and operating the compression of the product by said compression device;   radially forward displacing said compression device towards said drum and positioning said upper arm in a substantial alignment with said lower arm;   radially forward displacing said insertion device towards said drum;   pivotally lifting said arms, in phase with the rotation of said drum during the insertion of said stack in said drum, until a radial forward displacement run of the insertion device is completed;   reversing the motion of said lower arm, further lifting said upper arm, with the insertion device in a maximum forward displacement position close to the drum, and rearward displacing said compression device in order to avoid interference with said insertion device; and   returning said lower arm towards the lower dead end, reversing the motion of said upper arm and returning said insertion device by radial rearward displacement.   
     
     
         14 . The method according to  claim 13 , wherein in the insertion step of said stack in said compression device, the same stack frontally abuts on a stop which is driven independently and in a coordinated manner with respect to said lower arm. 
     
     
         15 . The method according to  claim 13 , wherein said insertion means carry out a continuous loop revolution around at least a portion of said compression means. 
     
     
         16 . The method according to  claim 13 , wherein a median plane of a stack with respect to its height in the maximum compression within said compression device, during said phased rotation of said arms, lies in a diametrical plane of said drum. 
     
     
         17 . The unit according to  claim 5 , wherein in said lower dead point of said lower arm, corresponding to an insertion phase of said stacks in said compression device, said lower arm is inclined with respect to the horizontal direction, with a descending inclination toward said drum about 10°.