Automatic Packaging Machine

Abstract

Automatic packaging machine, comprising a tubular forming element ( 1 ) into which the product ( 6 ) to be packaged is introduced and around which at least one layer of plastic film ( 2 ) for forming the packages ( 13 ) is wrapped; this machine comprises: forming means ( 7 ) for wrapping the film ( 2 ) around said tubular element ( 1 ) so that at least two strips ( 2′,2 ″) of said film are superimposed in the longitudinal direction (L); means ( 9, 91 ) for feeding said film ( 2 ) along said tubular element ( 1 ); at least one welding bar ( 11 ) able to perform a longitudinal weld of said superimposed strips of the film ( 2 ); said bar ( 11 ) is able to move at least in a transverse direction (T) towards or away from said tubular forming element ( 1 ); and movable units ( 14, 14′, 14″, 114 ) for transversely welding and cutting the film ( 2 ) in tubular form leaving said tubular forming element ( 1 ), said movable units ( 14, 14′, 14″, 114 ) being positioned downstream of said longitudinal welding bar ( 11 ) on at least two diametrically opposite sides of the film ( 2 ).

1 . Automatic packaging machine, comprising a tubular forming element into which the product to be packaged is introduced and around which at least one layer of plastic film for forming the packages is wrapped, characterized in that it comprises: forming means for wrapping the film around said tubular element so that at least two strips of said film are superimposed in the longitudinal direction; means for feeding said film along said tubular element; at least one welding bar able to perform a longitudinal weld of said superimposed strips of the film, said bar being able to move at least in a transverse direction towards or away from said tubular forming element; and movable units for transversely welding and cutting the film in tubular form leaving said tubular forming element, said movable units being positioned downstream of said longitudinal welding bar on at least two diametrically opposite sides of the film. 
     
     
         2 . Machine according to  claim 1 , characterized in that said longitudinal welding bar is movable in either sense also in the longitudinal direction with respect to the tubular forming element and said movable transverse welding and cutting units are fixed to guiding and driving elements which allow said units to follow cyclical closed-loop paths. 
     
     
         3 . Machine according to  claim 1 , characterized in that said movable welding bar follows a cyclical closed-loop path comprising: a first longitudinal welding movement in the direction of travel of the film where it is located at a minimum distance from the tubular forming element; a second transverse movement away from the tubular forming element; a third longitudinal return movement in the opposite direction to the direction of the first longitudinal movement; and a final transverse movement towards the tubular forming element. 
     
     
         4 . Machine according to  claim 1 , characterized in that said movable longitudinal welding bar comprises reaction means positioned inside the tubular forming element and movable longitudinally together with said movable bar, said tubular forming element being provided with a longitudinal groove designed to allow cooperation of said movable bar with the associated reaction means. 
     
     
         5 . Machine according to  claim 4 , characterized in that said reaction means comprise a reaction bar positioned inside a closed longitudinal groove formed along the tubular forming element, said reaction bar being positioned flush with the outer surface of said tubular forming element so that the superimposed strips of film to be welded longitudinally are positioned between it and the longitudinal welding bar. 
     
     
         6 . Machine according to  claim 4 , characterized in that said reaction means comprise a tubular member located coaxially inside the tubular forming element, said tubular forming element being provided with a longitudinal groove which allows cooperation between said movable longitudinal welding bar and said tubular reaction member. 
     
     
         7 . Machine according to  claim 1 , characterized in that said movable longitudinal welding bar is connected, by means of an associated movable frame, to an actuating slide sliding along a longitudinal guide fixed to a support structure, said slide being displaced by means of suitable operating means. 
     
     
         8 . (canceled) 
     
     
         9 . Machine according to  claim 1 , characterized in that said tubular forming element comprises upstream a forming collar provided with a rear inclined surface, two front surfaces inclined in the opposite direction to said rear surface and at least two elements for superimposing the two strips of the plastic film wrapped around said front surfaces, said superimposing elements being suitably spaced from each other. 
     
     
         10 . (canceled) 
     
     
         11 . Machine according to  claim 1 , characterized in that said means for feeding the film along the tubular forming element comprise at least one pair of belts in contact with the tubular forming element and therefore with the film in two diametrically opposite positions and provided with suitable conveying rollers. 
     
     
         12 . (canceled) 
     
     
         13 . Machine according to  claim 1 , characterized in that said elements for guiding and driving the movable transverse welding and cutting units form on the sides of the film leaving the tubular forming element two closed and identical annular paths along each of which at least two of said movable units are constrained in diametrically opposite positions, so that each welding unit situated on one side of the film is coupled, along a straight, working, welding section of said annular path, with a corresponding welding unit situated on the other side of the film. 
     
     
         14 . Machine according to  claim 13 , characterized in that each of said annular paths formed by said guiding and driving elements comprises a first straight, working, welding section, a first arc-like connecting section, a second straight return section and a second arc-like connecting section. 
     
     
         15 . Machine according to  claim 13 , characterized in that each of said annular paths formed by said guiding and driving elements has a triangular shape and comprises three straight sections on each of which a movable unit for transversely welding and cutting the film is positioned. 
     
     
         16 . Machine according to  claim 13 , characterized in that each of said welding units comprises on one side welding teeth and cutting means, said welding teeth being fastened by means of rotational pins to a support element fastened to at least one pair of chains or belts for driving said welding units along said closed-loop path. 
     
     
         17 .- 19 . (canceled) 
     
     
         20 . Machine according to  claim 16 , characterized in that each movable welding and cutting unit comprises, between said welding teeth, centring means for allowing correct alignment and relative positioning of a first movable unit provided along an annular path and situated on one side of the film with an associated second movable unit situated along the other annular path positioned on the other side of the film. 
     
     
         21 . Machine according to  claim 20 , characterized in that said centring means comprise a nose formed on a first movable unit between said welding teeth and a corresponding notch formed on a second movable unit which, during transverse welding and cutting of the film, must be coupled with said first movable unit. 
     
     
         22 . Machine according to  claim 16 , characterized in that the elements supporting the movable welding units are connected to a support plate to which an arm is fastened, said arm having, fixed thereto, a plurality of contacts making sliding contact along electrified tracks which follow the path of said drive chains or belts of the movable units. 
     
     
         23 . Machine according to  claim 1 , characterized in that each of the movable welding units comprises a pair of rollers travelling along a cam track guiding said movable units during their annular movement along said closed-loop paths. 
     
     
         24 . (canceled) 
     
     
         25 . Machine according to  claim 1 , characterized in that each of said movable transverse welding units comprises metal heads designed to slide along the associated metal annular tracks in order to detect the operating temperature of said movable units. 
     
     
         26 . Machine according to  claim 1 , characterized in that each of said movable transverse welding and cutting units comprises a box-shaped body having, positioned inside it, at least one blade or a counter-blade movable transversely in either sense for transversely cutting the film. 
     
     
         27 . Machine according to  claim 26 , characterized in that said blade or counter-blade is connected to a head which is displaceable transversely and which carries rollers travelling along a cam track controlling said blade or said counter-blade, said head being connected to said blade or to said counter-blade by means of a tubular element which passes through said support plate. 
     
     
         28 . (canceled) 
     
     
         29 . Machine according to  claim 2 , characterized in that it comprises members for folding the bottom of the packages, positioned upstream of the said movable transverse welding and cutting units on two diametrically opposite sides of the film in tubular form, each of said folding members being connected to at least one pair of longitudinal arms able to pivot so as to move towards or away from said film, and therefore the tubular forming element, via suitable guiding and operating means. 
     
     
         30 .- 33 . (canceled) 
     
     
         34 . Machine according to  claim 11 , characterized in that at least one of said rollers of one of said belts feeding the film is fixed to a shaft connected to a motor for operating and acting as a counterweight for said belts, each of said belts being supported by a plate pivoting relative to a structure in turn pivoting and hinged on a fixed structure. 
     
     
         35 . Machine according to  claim 34 , characterized in that said shaft, intended for at least one roller of at least one of said belts and operated by said motor, has, keyed thereon, a toothed wheel around which there is wound a belt or chain for transmitting the movement to a second toothed wheel keyed onto a second shaft provided on at least one roller of the other belt feeding the film. 
     
     
         36 . Machine according to  claim 23 , characterized in that said cam tracks guiding the movable transverse welding and cutting units comprise working welding sections which are interchangeable and have active transverse welding sections of different lengths. 
     
     
         37 . Machine according to  claim 1 , characterized in that it comprises two units for transversely welding and cutting the film which are arranged opposite each other and are designed to weld and cut said film at the same moment the bar located upstream performs the longitudinal weld. 
     
     
         38 . Machine according to  claim 1 , characterized in that it comprises pairs of movable means for clamping in position the film to be welded, said means being provided with a least one opening for receiving the transverse welding heads and the elements for transversely cutting the film. 
     
     
         39 . Machine according to  claim 38 , characterized in that said movable means for clamping the film in position are supported by means of the plates designed to travel along closed-loop tracks, movable means for driving said plates being provided along the said tracks. 
     
     
         40 . Machine according to  claim 39 , characterized in that it comprises a support structure, on each side wall of which two closed-loop and symmetrically arranged tracks are positioned, at least one of said plates supporting the means for clamping the film in position travelling along each section of said tracks. 
     
     
         41 . Machine according to  claim 1 , characterized in that it comprises, upstream of the tubular forming element, a dispenser for dispensing loose material, having at least one pair of chambers designed to supply alternately said tubular forming element with said loose material. 
     
     
         42 . Machine according to  claim 1 , characterized in that it comprises movable baffles designed to be introduced or extracted, along the sides of the channel through which the loose material passes, into/from the tubular forming element so as to form steps able to limit the falling height of the loose material inside said through-channel.