Abstract Apparatus for packaging articles between two heat-sealable plastic films. The apparatus feeds roll-stock film over an infeed conveyor and articles to be packaged are placed on the film. A second roll-stock film is fed over the top of the articles and sealed to the bottom film by a transverse timed-drop heat-sealing knife. The sealing knife operates between spring tensioned clamping bars which hold the films together both fore and aft of the sealing knife. The lower clamping bar is provided with a series of air vents for cooling the transverse seals. The sides of the package are sealed by a pair of heat-sealing wheels which are insulated by inwardly spaced discs to protect the articles being packaged against scorching. A perforator saw wheel runs on the top film as it passes over a rubber roller to provide a perforated line of weakness in the top film.
In a packaging machine having means for advancing two plastic films in overlapping relation, the improvement comprising: a. a carriage frame mounted on said machine for movement between an upper rest position and a lower working position, b. a pair of substantially parallel spaced elongate upper clamping surfaces mounted in said carriage frame transversely to the direction of travel of said films for substantially vertical reciprocal movement in said carriage frame, c. a lower clamping bar having a generally U-shaped cross section and having a pair of flanges providing a pair of lower clamping surfaces, d. a plurality of air vents formed in said flanges along the length of said lower clamping bar below said lower clamping surfaces, e. a heat-sealing knife mounted in said carriage frame for movement therewith between said upper rest position and said lower work position, said knife being positioned in said carriage frame between said spaced upper clamping surfaces, and f. means for lowering said carriage frame to bring said upper and lower clamping surfaces together to hold said films therebetween and to bring said heat-sealing knife into sealing engagement with said films between the area where the films are held by said upper and lower clamping surfaces.
Claim 2
Dependent Claim
203 words
In a packaging machine having means for advancing two plastic films in overlapping relation, the improvement comprising: a. a carriage frame mounted on said machine for movement between an upper rest position and a lower working position, b. a pair of substantially parallel spaced elongate upper clamping surfaces mounted in said carriage frame transversely to the direction of travel of said films for substantially vertical reciprocal movement in said carriage frame, c. a lower clamping bar having a generally U-shaped cross section and having a pair of flanges providing a pair of lower clamping surfaces, d. a plurality of air vents formed in said flanges along the length of said lower clamping bar below said lower clamping surfaces, e. a heat-sealing knife mounted in said carriage frame for movement therewith between said upper rest position and said lower work position, said knife being positioned in said carriage frame between said spaced upper clamping surfaces, and f. means for lowering said carriage frame to bring said upper and lower clamping surfaces together to hold said films therebetween and to bring said heat-sealing knife into sealing engagement with said films between the area where the films are held by said upper and lower clamping surfaces.