Patent ID: 7080495
Filing Date: 2006-07-25
Classification: B65B

Abstract:
1. A wrapping apparatus for winding a wrapping film about an article to be wrapped, said wrapping apparatus including a film dispenser arranged to revolve along a circular track at a substantially constant velocity about the article to be wrapped, said film dispenser comprising: a frame; supporting elements adapted to support a film roll on said frame, said film roll being freely rotatable; a film pre-stretcher comprising a first pre-stretching roller freely rotatably mounted on said frame to receive film from said film roll and a second pre-stretching roller freely rotatably mounted on said frame and disposed in a position parallel to and at a distance from said first pre-stretching roller, said first and second pre-stretching rollers being coupled together to have different circumferential velocities such that a portion of said film located between said first and second pre-stretching rollers is pre-stretched; a freely rotatable pendulum roller and a spring, said pendulum roller being disposed after said second pre-stretching roller in a direction of film movement to receive said pre-stretched film from said second pre-stretching roller, and said pendulum roller being spring-loaded by said spring acting against a drawing direction of said film; and a deflecting roller freely rotatably mounted on said frame in a position parallel to said first and second pre-stretching rollers and said pendulum roller, said film coming from said pendulum roller and passing over said deflecting roller to the article being wrapped; wherein said pendulum roller and said spring are adapted so that a bend is formed between said pendulum roller and said second pre-stretching roller, said deflecting roller acting as a film supply to contain a varying amount of film, depending on a prevailing draw of said film, to maintain a substantially constant drawing velocity and tension of said film from said second pre-stretching roller regardless of variations in said draw and velocity of said film in relation to said film dispenser, said variations in said draw and velocity of said film being caused by a shape of the article being wrapped; and wherein said spring pendulum roller, said second pre-stretching roller and said deflecting roller are arranged to maintain a substantially constant film tension regardless of a position of said pendulum roller.