Machine for manufacturing square bags of thermoplastic film

Claim 2

A machine for manufacturing a square bag consisting of a flat tubular body made of thermoplastic film with the outer surface thereof processed to be hardly weldable and having its top opening closed by the use of a cover plate with a valve plate, said machine comprising: a pair of elongated surface plates installed face to face with a slit therebetween, said plates being equipped with plural upper clamp mechanisms for holding said tubular body between said plates at fixed intervals therealong; a conveying apparatus movable along said surface plates for conveying said tubular body along said slit, said conveying apparatus including plural lower clamp mechanisms for holding said tubular body positioned between said surface plates, whereby when the tubular body is held by the lower clamp mechanisms it is conveyed along the slit between the surface plates by forward movement of the conveying apparatus, and wherein the corresponding upper clamp mechanisms hold said tubular body when the tubular body is released from the lower clamp mechanisms so that the conveying apparatus returns to its former position; means for opening the top of the tubular body when said tubular body is being held by said upper clamp mechanisms; a press device for pressing the open top of the tubular body against the surface plates and forming front and rear horizontal flaps and a pair of bisymmetric triangular end flaps lapping over two sides of said flaps on said top; a first apparatus for installing the valve plate into the pressed top of the tubular body, said first apparatus inserting one side edge of the valve plate as held on a receiving plate beneath one triangular end flap, then releasing the valve plate from the receiving plate and pulling out the receiving plate from beneath the triangular end flap; a second apparatus for installing the cover plate into the pressed top of the tubular body, said second apparatus inserting one side edge of the cover plate as held on a receiving plate beneath the other triangular end flap and at the same time overlapping the other side edge of said cover plate over the valve plate, then releasing the cover plate from the receiving plate and pulling out the receiving plate from beneath said other triangular end flap; means for heat-sealing the overlapping portions when the valve plate and the cover plate have been inserted beneath the triangular end flaps by said first and second apparatuses; and means for heat-sealing the front and rear edges of the valve plate and the cover plate onto the front and rear edges of the horizontal flaps of the tubular body.

Claim 3

A machine for manufacturing a square bag consisting of a flat tubular body made of thermoplastic film with the outer surface thereof processed to be hardly weldable and having its openings closed by cover plates, said machine comprising: a pair of elongated surface plates installed face to face with a slit therebetween, said plates being equipped with plural upper clamp mechanisms for holding said tubular body between said plates at fixed intervals therealong; a conveying apparatus movable along said plates for conveying said tubular body along said slit, said conveying apparatus including plural lower clamp mechanisms for holding said tubular body positioned between said surface plates, whereby when the tubular body is held by the lower clamp mechanisms it is conveyed along the slit between the surface plates by forward movement of the conveying apparatus, and wherein the corresponding upper clamp mechanisms hold said tubular body when the tubular body is released from the lower mechanisms so that the conveying apparatus returns to its former position; means for opening the top of the tubular body when said tubular body is being held by said upper clamp mechanisms; a press device for pressing the open top of the tubular body against the surface plates and forming front and rear horizontal flaps and a pair of bisymmetric triangular end flaps lapping over two sides of said flaps on said top; an apparatus for installing the cover plate into the pressed top of the tubular body, said apparatus inserting two side edges of the cover plate as held on a receiving plate beneath the respective triangular end flaps, then releasing the cover plate from the receiving plate after the portion of the cover plate inserted beneath the triangular end flap has been heat-sealed and pulling out the receiving plate from beneath the triangular end flaps; means for heat-sealing the overlapping portions when the cover plate has been inserted beneath the triangular end flaps; and means for heat-sealing the front and rear edges of the cover plate onto the front and rear edges of the horizontal flaps of the tubular body.

Claim 4

A machine for manufacturing a square bag consisting of a flat tubular body made of thermoplastic film with the outer surface thereof processed to be hardly weldable and having its openings closed by cover plates, said machine comprising: a pair of elongated surface plates installed face to face with a slit therebetween, said plates being equipped with plural upper clamp mechanisms for holding said tubular body between said plates at fixed intervals therealong; a conveying apparatus movable along said plates for conveying said tubular body along said slit, said conveying apparatus including plural lower clamp mechanisms for holding said tubular body positioned between said surface plates, whereby when the tubular body is held by the lower clamp mechanisms it is conveyed along the slit between the surface plates by forward movement of the conveying apparatus, and wherein the corresponding upper clamp mechanisms hold said tubular body when the tubular body is released from the lower mechanisms so that the conveying apparatus returns to its former position; means for opening the top of the tubular body when said tubular body is being held by said upper clamp mechanisms; a press device for pressing the open top of the tubular body against the surface plates and forming front and rear horizontal flaps and a pair of bisymmetric triangular end flaps lapping over two sides of said flaps on said top; an apparatus for installing the cover plate into the pressed top of the tubular body, said apparatus inserting two side edges of the cover plate as held on a receiving plate beneath the respective triangular end flaps, then releasing the cover plate from the receiving plate after the portion of the cover plate inserted beneath the triangular end flap has been heat-sealed and pulling out the receiving plate from beneath the triangular end flaps; means for heat-sealing the overlapping portions when the cover plate has been inserted beneath the triangular end flaps; and means for heat-sealing the front and rear edges of the cover plate onto the front and rear edges of the horizontal flaps of the tubular body.

Claim 5

A machine for manufacturing a square bag having a flat tubular body made of plastic film and having its end openings closed by cover plates, said machine comprising: elongated guide means defining an elongated guide slot through which the tubular body is guidably moved during formation of the bag, said guide means defining a plurality of working stations positioned sequentially therealong; a plurality of first clamping mechanisms associated with said guide means at the individual stations therealong for permitting clamping of the tubular body at the individual working stations, said first clamping means including a pair of opposed clamping members for clampingly engaging the tubular body therebetween to maintain said tubular body in a supported position; conveying means for sequentially moving said tubular body in an intermittent steplike manner between adjacent working stations, said conveying means including a carriage movably supported adjacent said guide means and a drive mechanism connected to said carriage for moving said carriage in a reciprocating manner along a line of movement which is substantially parallel with the longitudinal direction of said slot, said drive mechanism causing said carriage to reciprocate back and forth through a distance substantially equal to the spacing between adjacent working stations; a plurality of second clamping mechanisms mounted on said carriage at spaced intervals therealong for engaging the tubular body and moving same between adjacent working stations, said second clamping mechanism including opposed clamping members which engage the tubular body therebetween for advancing the tubular body from one working station into the next adjacent working station during forward movement of the carriage, said second clamping mechanisms being released from the tubular body during return movement of the carriage whereupon the tubular body is maintained in the next adjacent working station by one of said first clamping mechanisms; separation means for separating the sidewalls of the tubular body adjacent one of said end openings for opening said one end opening, said end opening being disposed adjacent a first working station and said separation means acting on said tubular body when same is clampingly held in said first working station by one of said first clamping mechanisms; pressing means for pressing the previously opened end of the tubular body against said guide means for forming a pair of side flaps which are spread outwardly in opposite directions and extend substantially transversely from opposite sides of the tubular body and for also simultaneously forming a pair of bisymmetric triangular end flaps which each overlap the two side flaps, said pressing means being located at a second working station which is disposed adjacent said first working station but displaced downstream therefrom, said tubular body being clampingly held in said second working station by one of said first clamping mechanisms when said pressing means acts thereon; an apparatus for inserting the cover plate into the pressed end of the tubular body so that one end of the cover plate is inserted between the triangular end flap and the adjacent overlapped portions of the side flaps, said apparatus being positioned at a third working station which is disposed adjacent said second station but is displaced downstream thereof, said tubular body being maintained in said third working station by one of said first clamping mechanisms when said apparatus acts thereon; and means for heat-sealing the cover plate to the tubular body.

Claim 6

A machine for manufacturing a square bag having a flat tubular body made of plastic film and having its end openings closed by cover plates, said machine comprising: elongated guide means defining an elongated guide slot through which the tubular body is guidably moved during formation of the bag, said guide means defining a plurality of working stations positioned sequentially therealong; a plurality of first clamping mechanisms associated with said guide means at the individual stations therealong for permitting clamping of the tubular body at the individual working stations, said first clamping means including a pair of opposed clamping members for clampingly engaging the tubular body therebetween to maintain said tubular body in a supported position; conveying means for sequentially moving said tubular body in an intermittent steplike manner between adjacent working stations, said conveying means including a carriage movably supported adjacent said guide means and a drive mechanism connected to said carriage for moving said carriage in a reciprocating manner along a line of movement which is substantially parallel with the longitudinal direction of said slot, said drive mechanism causing said carriage to reciprocate back and forth through a distance substantially equal to the spacing between adjacent working stations; a plurality of second clamping mechanisms mounted on said carriage at spaced intervals therealong for engaging the tubular body and moving same between adjacent working stations, said second clamping mechanism including opposed clamping members which engage the tubular body therebetween for advancing the tubular body from one working station into the next adjacent working station during forward movement of the carriage, said second clamping mechanisms being released from the tubular body during return movement of the carriage whereupon the tubular body is maintained in the next adjacent working station by one of said first clamping mechanisms; separation means for separating the sidewalls of the tubular body adjacent one of said end openings for opening said one end opening, said end opening being disposed adjacent a first working station and said separation means acting on said tubular body when same is clampingly held in said first working station by one of said first clamping mechanisms; pressing means for pressing the previously opened end of the tubular body against said guide means for forming a pair of side flaps which are spread outwardly in opposite directions and extend substantially transversely from opposite sides of the tubular body and for also simultaneously forming a pair of bisymmetric triangular end flaps which each overlap the two side flaps, said pressing means being located at a second working station which is disposed adjacent said first working station but displaced downstream therefrom, said tubular body being clampingly held in said second working station by one of said first clamping mechanisms when said pressing means acts thereon; an apparatus for inserting the cover plate into the pressed end of the tubular body so that one end of the cover plate is inserted between the triangular end flap and the adjacent overlapped portions of the side flaps, said apparatus being positioned at a third working station which is disposed adjacent said second station but is displaced downstream thereof, said tubular body being maintained in said third working station by one of said first clamping mechanisms when said apparatus acts thereon; and means for heat-sealing the cover plate to the tubular body.

Claim 7

A machine according to claim 3, wherein the first clamping mechanisms maintain the tubular body in a vertically suspended position when held in said first, second and third working stations, the separating means and the pressing means acting on the top end of said tubular body for permitting the cover plate to be attached thereto; inverting means located at a fourth working station disposed downstream of said heat sealing means for engaging said tubular body and rotating same within a vertical plane through an angle of substantially 180° so that the other open end of the tubular body is located at the top of said tubular body; second conveying means for transferring the thus inverted tubular body from said inverting means downstream into further spaced working stations, said second conveying means including a second reciprocating carriage which is movable back and forth between adjacent working stations; and a mechanism located at a further working station disposed downstream of said inverting mechanism for attaching a further cover plate to the other open end of said bag, which other open end is now located at the upper end of said tubular body.

Claim 8

A machine according to claim 4 wherein said inverting means comprises: a frame supported for rotation about a substantially horizontal axis, said frame having first and second arm means projecting outwardly in opposite directions from and substantially perpendicular to said axis; each said arm means being of a bifurcated construction and including first and second horizontally spaced arm portions having an elongated slot therebetween which opens outwardly of said arm means through the free end thereof; third and fourth clamping mechanisms respectively mounted on said first and second arm means, each of said third and fourth clamping mechanisms including first and second clamping portions respectively associated with the first and second arm portions for permitting the tubular bag body to be clampingly held between the clamping portions when the bag body is inserted into one of the elongated slots; means associated with said third and fourth clamping mechanisms for permitting selective activation or deactivation thereof; and drive means connected to said frame for causing angular roation thereof about said horizontal axis from a first position wherein said bag body is inserted into one of said slots to a second position wherein said bag body is removed from said one slot.

Claim 9

A machine according to claim 5, wherein said first and second arm means each include first and second arms which are substantially parallel and are vertically spaced apart so that said frame has a substantially H-shaped configuration, each of said first and second arms being defined by said horizontally spaced first and second arm portions having an elogated slot disposed therebetween, and said third and fourth clamping mechanisms each including a pair of clamping devices one of which is associated with each of said first and second arms so that the tubular bag body is grippingly engaged adjacent the opposite ends thereof.