Film dispenser for a wrapping apparatus and related methods

A film dispenser for a wrapping apparatus, comprising:

• a dispenser roller configured to provide a material web at a film delivery speed;
• a film dispenser motor operatively connected to the dispenser roller;
• a dancer bar positioned downstream of the dispenser roller and being engageable with the material web, the dancer bar being movable over a displacement range between a first position and at least one second position in response to a variation of a film feed requirement, the dancer bar being in the first position when a tension in the material web is below a threshold and being in the at least one second position when the tension in the material web is equal or above the threshold;
• and
• a dancer bar control assembly operatively connected to the dancer bar, the dancer bar control assembly being configured to:
• bias the dancer bar with a constant force over the displacement range;
• monitor a displacement of the dancer bar;
• and
• generate a speed command based on the monitored displacement of the dancer bar and send the speed command towards a film dispenser motor to adjust the film delivery speed;
• wherein the displacement of the dancer bar is a translation between the first position and the at least one second position;
• and
• wherein the dancer bar control assembly comprises:
• a first linear servo motor operatively connected to a first end of the dancer bar, the first linear servo motor being configured to detect and guide a translation of the first end along a first axis;
• and
• a second linear servo motor operatively connected to a second end of the dancer bar, the second linear servo motor being configured to detect and guide a translation of the second end along a second axis.

A film dispenser for a wrapping apparatus, comprising:

• a dispenser roller configured to provide a material web at a film delivery speed;
• a film dispenser motor operatively connected to the dispenser roller;
• a dancer bar positioned downstream of the dispenser roller and being engageable with the material web, the dancer bar being movable over a displacement range between a first position and at least one second position in response to a variation of a film feed requirement, the dancer bar being in the first position when a tension in the material web is below a threshold and being in the at least one second position when the tension in the material web is equal or above the threshold;
• and
• a dancer bar control assembly operatively connected to the dancer bar, the dancer bar control assembly being configured to:
• bias the dancer bar with a constant force over the displacement range;
• monitor a displacement of the dancer bar;
• and
• generate a speed command based on the monitored displacement of the dancer bar and send the speed command towards a film dispenser motor to adjust the film delivery speed;
• wherein the displacement of the dancer bar is a rotation between the first position and the second position, and the dancer bar is rotatable about a rotation axis;
• and
• wherein the dancer bar control assembly comprises a rotatory servo motor operatively connected to a first end of the dancer bar, the rotatory servo motor being configured to detect and guide a rotation of the first end about the rotation axis.

A film dispenser for a wrapping apparatus, comprising:

• a dispenser roller configured to provide a material web at a film delivery speed;
• a film dispenser motor operatively connected to the dispenser roller;
• a dancer bar positioned downstream of the dispenser roller and being engageable with the material web, the dancer bar being movable over a displacement range between a first position and at least one second position in response to a variation of a film feed requirement, the dancer bar being in the first position when a tension in the material web is below a threshold and being in the at least one second position when the tension in the material web is equal or above the threshold;
• and
• a dancer bar control assembly operatively connected to the dancer bar, the dancer bar control assembly being configured to:
• bias the dancer bar with a constant force over the displacement range;
• monitor a displacement of the dancer bar;
• and
• generate a speed command based on the monitored displacement of the dancer bar and send the speed command towards a film dispenser motor to adjust the film delivery speed;
• wherein the displacement of the dancer bar is a rotation between the first position and the second position, and the dancer bar is rotatable about a rotation axis;
• and
• wherein the dancer bar control assembly comprises:
• a magnetic assembly comprising a permanent magnet mounted inside the dancer bar and an inductive magnet mounted around the dancer bar;
• and
• an angular position sensor configured to measure an angular position of the dancer bar.

A film dispenser for a wrapping apparatus, comprising:

• a dispenser roller configured to provide a material web at a film delivery speed;
• a film dispenser motor operatively connected to the dispenser roller;
• a dancer bar positioned downstream of the dispenser roller and being engageable with the material web, the dancer bar being movable over a displacement range between a first position and at least one second position in response to a variation of a film feed requirement, the dancer bar being in the first position when a tension in the material web is below a threshold and being in the at least one second position when the tension in the material web is equal or above the threshold;
• and
• a dancer bar control assembly operatively connected to the dancer bar, the dancer bar control assembly being configured to:
• bias the dancer bar with a constant force over the displacement range;
• monitor a displacement of the dancer bar;
• and
• generate a speed command based on the monitored displacement of the dancer bar and send the speed command towards a film dispenser motor to adjust the film delivery speed;
• wherein the displacement of the dancer bar is a rotation between the first position and the second position, and the dancer bar is rotatable about a rotation axis;
• and wherein the dancer bar control assembly comprises:
• a magnetic assembly, comprising:
• a magnetic spring;
• a reel mountable near or at a first end of the dancer bar, the reel being engageable in rotation with the dancer bar;
• and
• a cable operatively connected to the magnetic spring, the cable being wounded around the reel upon rotation of the dancer bar;
• and
• a linear position sensor configured to measure a linear displacement of the cable.