Film supplying apparatus and lift mechanism for a packaging machine

A film supplying apparatus for a packaging machine which includes means for supporting film rolls having thereon films with various widths, film transporting belts extending between a first end position and a second end position and capable of clamping both side edges of an elongated film pulled out longitudinally from selected one of said film rolls and transporting said clamped film longitudinally in one or opposite direction to a packaging station, and switching means for switching the direction of film transportation by said film transporting belts;

• said film supplying apparatus comprising:
• sensors capable of detecting presence and absence of a film, a first group of said sensors being disposed at said first end position, a second group of said sensors being disposed at said second end position;
• and
• a controller for switching the roles of said first group and said second group of sensors, depending on the direction of film transportation by said film transporting belts, said first group of sensors serving to output a warning signal when said film is detected thereby and said second group of sensors serving to output a warning signal when the absence of film is detected thereby if the direction of film transportation by said film transporting belts is from said second end position to said first end position, said first group of sensors serving to output a warning signal when the absence of film is detected thereby and said second group of sensors serving to output a warning signal when said film is detected thereby if the direction of film transportation by said film transporting belts is from said first end position to said second end position, said controller further serving to control said film transporting belts according to the various width of said film and such that said film transporting belts automatically clamp said film.

A packaging machine comprising:

• a weighing apparatus for weighing articles on a tray;
• a packaging station;
• means for storing film rolls having thereon films with various widths;
• film transporting belts extending longitudinally between a first end position and a second end position and being capable of clamping both side edges of an elongated film pulled out longitudinally from a selected one of said film rolls and transporting said clamped film longitudinally in one or opposite direction to said packaging station;
• switching means for switching the direction of film transportation by said film transporting belts;
• a lift for lifting said articles on said tray, which have been weighed by said weighing apparatus, to said packaging station;
• a folding apparatus for wrapping said articles and said tray together in a piece of said film at said packaging station;
• a pair of film guiding mechanisms each capable of pulling a film out of an associated one of said film rolls and guiding said pulled film to an associated one of said first and second end positions of said film transporting belts;
• and
• a controller adapted, when said film transporting belts are in motion, to selectively activate one of said film guiding mechanisms that is on the upstream side of said motion, said controller further serving to control said film transporting belts according to the various width of said film and such that said film transporting belts automatically clamp said film.

A packaging machine comprising:

• a weighing apparatus for weighing articles on a tray;
• a packaging station;
• means for storing film rolls;
• film transporting belts extending longitudinally between a first end position and a second end position and being capable of clamping both side edges of an elongated film pulled out longitudinally from a selected one of said film rolls and transporting said clamped film longitudinally in one or opposite direction to said packaging station;
• switching means for switching the direction of film transportation by said film transporting belts;
• a lift for lifting said articles on said tray, which have been weighed by said weighing apparatus, to said packaging station;
• a folding apparatus for wrapping said articles and said tray together in a piece of said film at said packaging station;
• a pair of film guiding mechanisms each capable of pulling a film out of an associated one of said film rolls and guiding said pulled film to an associated one of said first and second end positions of said film transporting belts;
• and
• a controller adapted, when said film transporting belts are in motion, to selectively activate one of said film guiding mechanisms that is on the upstream side of said motion;
• said lift comprising:
• a frame;
• frame-lifting means for moving said frame selectively upward or downward;
• a plurality of posts standing on said frame for supporting trays thereon, said posts including fixed posts, which are affixed to said frame, and mobile posts, which can move in a specified direction within a specified range each towards or away from associated one of said fixed posts;
• guide members affixed to said frame and extending in said specified direction;
• and
• a slidable member extending perpendicularly to said specified direction and being mounted on and capable of sliding along said guide members in said specified direction beyond said specified range;
• said controller being further adapted to stop said slidable member at a plurality of stop positions within said specified range and wait positions outside said specified range and to cause said slidable member and said mobile posts to move towards or away from each other at any of said stop positions.

A packaging machine comprising:

• a weighing apparatus for weighing articles on a tray;
• a packaging station;
• means for storing film rolls;
• film transporting belts extending longitudinally between a first end position and a second end position and being capable of clamping both side edges of an elongated film pulled out longitudinally from a selected one of said film rolls and transporting said clamped film longitudinally in one or opposite direction to said packaging station;
• switching means for switching the direction of film transportation by said film transporting belts;
• a lift for lifting said articles on said tray, which have been weighed by said weighing apparatus, to said packaging station;
• a folding apparatus for wrapping said articles and said tray together in a piece of said film at said packaging station;
• a pair of film guiding mechanisms each capable of pulling a film out of an associated one of said film rolls and guiding said pulled film to an associated one of said first and second end positions of said film transporting belts;
• a controller adapted, when said film transporting belts are in motion, to selectively activate one of said film guiding mechanisms that is on the upstream side of said motion;
• and
• sensors capable of detecting presence and absence of a film, a first group of said sensors being disposed at said first end position, a second group of said sensors being disposed at said second end position;
• said controller being further adapted to switch the roles of said first group and said second group of sensors, depending on the direction of film transportation by said film transporting belts, said first group of sensors serving to output a warning signal when said film is detected thereby and said second group of sensors serving to output a warning signal when the absence of film is detected thereby if the direction of film transportation by said film transporting belts is from said second end position to said first end position, said first group of sensors serving to output a warning signal when the absence of film is detected thereby and said second group of sensors serving to output a warning signal when said film is detected thereby if the direction of film transportation by said film transporting belts is from said first end position to said second end position;
• said lift comprising:
• a frame;
• frame-lifting means for moving said frame selectively upward or downward;
• a plurality of posts standing on said frame for supporting trays thereon, said posts including fixed posts, which are affixed to said frame, and mobile posts, which can move in a specified direction within a specified range each towards or away from associated one of said fixed posts;
• guide members affixed to said frame and extending in said specified direction;
• and
• a slidable member extending perpendicularly to said specified direction and being mounted on and capable of sliding along said guide members in said specified direction beyond said specified range;
• said controller being still further adapted to stop said slidable member at a plurality of stop positions within said specified range and wait positions outside said specified range and to cause said slidable member and said mobile posts to move towards or away from each other at any of said stop positions.