Fly-knife dampening system

A system for use in machine for making bags from a polymeric film, said system comprising:

• an elongate bed knife having a bed knife blade, said bed knife being stationary during use of the system;
• an elongate rotating fly-knife having a fly-knife blade and plural and spaced apart fly-knife cams disposed thereon, said fly-knife blade being operatively engageable with said bed knife to perform operations on the film;
• an elongate rotating support shaft having plural and spaced apart support cams mounted thereon, said support cams disposed such that contact is made between said support cams and fly-knife cams each time said fly-knife blade operatively engages said bed knife;
• and
• wherein said bed knife is mounted for rotational movement away from said fly-knife, whereby the film can pass through the juncture of said fly-knife and said bed knife without having operations performed thereon when the system is not in use.

In a machine for making plastic bags from plastic film moving along a film path of the type comprising a drum-shaped rotatable sealing means for sealing said film, blanket means surrounding a portion of said sealing means and rotatably driving said sealing means, folding means located along said path, and knife means along said path for selectively cutting and perforating said film to form interconnected bags, the improvement wherein:

• said knife means comprises:
• an elongate bed knife which is stationary during use of the system and including a bed knife blade;
• an elongate rotating fly-knife including a fly-knife blade rotatable about a longitudinal axis and having plural and spaced apart cams disposed thereon, said fly-knife
• blade being operatively engagable with said bed knife blade at a predetermined time during rotation of the fly-knife;
• and
• a rotating support shaft parallel to, but spaced apart from said rotating fly-knife, said support shaft having plural and spaced apart support cams mounted thereon for rotation therewith, said support cams disposed such that each time said fly-knife blade operatively engages said bed-knife blade, said support cams engage said fly-knife cams.

A system for use in a winder for winding elongate strips of pliable material, such as plastic film, cloth or paper, into coreless rolls, said system comprising:

• an elongate bed knife which is stationary during use of the system having a bed knife blade;
• an elongate rotating fly-knife having a fly-knife blade and plural and spaces apart cams disposed thereon, said fly-knife blade being operatively engagable with said bed knife blade to sever said pliable material;
• a rotating support shaft parallel to, but spaced apart from said rotating fly-knife, said support shaft having plural and spaced apart cams mounted thereon for rotation therewith;
• wherein said support cams are disposed such that contact is made between said support cams and said fly-knife cams when said fly-knife blade operatively engages said bed knife blade to sever said pliable material.