Speed adjustable packaging machine

A packaging machine adapted to form a sealing line on a package film enclosing an article, the packaging machine comprising

• a machine chassis;
• a sealing device mounted to the machine chassis, the sealing device comprising upper and lower members movable with respect to each other between an open position where the upper and lower members are separated from each other at a predetermined distance for reception of the article and the package film therebetween and a closed position where the upper and lower members engage the package film for performing a sealing operation;
• an adjustment device comprising a platform movable with respect to the machine chassis between a forward position and a backward position;
• a driving device mounted to the platform, the driving device comprising an extendable rod having a remote end movable between an extended position and a retracted position;
• a cross bar rotatably supported in the machine chassis and mechanically coupled to the extendible rod whereby when the extendible rod is moved from the extended position to the retracted position, the cross bar is rotated in a first angular direction from a first angular position to a second angular position and when the extendible rod is moved from the retracted position to the extended position, the cross bar is rotated in a second angular direction from the second angular position to the first angular position;
• a rocking arm fixedly attached to the cross bar;
• and,
• first and second connecting rods respectively connected between the ends of the rocking arm and the upper and lower members whereby when the cross bar is rotated in the first angular direction from the first angular position toward the second angular position, the upper and lower members are driven by the first and second connecting rods from the open position to the closed position and when the cross bar is rotated in the second angular direction from the second angular position toward the first angular position, the upper and lower members are driven by the first and second connecting rods from the closed position to the open position, the platform of the adjusting device being selectively displaced between the backward position and the forward position to drive the cross bar to rotate and thereby change an opening distance between the upper and lower members in the open position.