Reefing under stretch
The present invention relates to a method for gathering-up a tubular film portion on at least two gathering fingers of a packaging machine and to a gathering apparatus of a packaging machine for carrying out the method as claimed in the invention. The method is distinguished in that the tubular film portion is expanded at least in a part region when being gathered-up onto the gathering fingers. The gathering apparatus as claimed in the invention is distinguished in that the gathering fingers can be driven into a gathering-up position for gathering-up the tubular film portion, in which gathering-up position the tubular film portion is expanded at least in a part region.
1. A method for operating a wrapping machine, the method comprising:
operatively connecting a first contact roller of a first gathering finger with a first gathering roller to hold a first portion of tubular film therebetween;
operatively connecting a second contact roller of a second gathering finger with a second gathering roller to hold a second portion of the tubular film therebetween;
afterwards, maintaining the first and second gathering fingers in a gathering configuration while driving the first and second gathering rollers to gather the tubular film onto the first and second gathering fingers such that the tubular film stretches to a second perimeter length greater than a first unstretched perimeter length when driven over the first and second contact rollers and, after being driven over the first and second contact rollers, contracts onto the first and second gathering fingers to a third perimeter length and forms folds along the first and second gathering fingers; and
after gathering the tubular film onto the first and second gathering fingers, moving the first and second gathering fingers laterally outward relative to one another into a wrapping configuration to stretch the tubular film to a fourth perimeter length.
2. The method of claim 1 , wherein the first and second gathering fingers are laterally spaced apart a designated distance while in the gathering configuration and while the tubular film is being gathered onto the first and second gathering fingers.
3. The method of claim 1 , wherein the third perimeter length is between the first and second perimeter lengths.
4. The method of claim 1 , wherein a first axis of rotation of the first gathering roller and a second axis of rotation of the first contact roller are not vertically offset from one another.
5. The method of claim 1 , wherein a first axis of rotation of the first gathering roller and a second axis of rotation of the first contact roller are in a horizontal plane, and wherein the horizontal plane is perpendicular to a third axis of the first gathering finger.
6. The method of claim 1 , further comprising, after moving the first and second gathering fingers into the wrapping configuration, moving the first and second gathering fingers vertically relative to an object while driving the first and second gathering rollers to discharge the tubular film from the first and second gathering fingers such that the tubular film contracts onto the object.
7. A method for wrapping an object with tubular film having an unstretched perimeter length, the method comprising:
maintaining a plurality of gathering fingers in a gathering configuration while driving a plurality of gathering rollers to gather the tubular film onto the plurality of gathering fingers such that the tubular film stretches to a perimeter length greater than the unstretched perimeter length;
afterwards, moving the plurality of gathering fingers laterally outward relative to one another into a wrapping configuration to stretch the tubular film to a perimeter length sufficient to wrap the object; and
with the plurality of gathering fingers in the wrapping configuration, vertically moving the plurality of gathering fingers while driving the plurality of gathering rollers to discharge the tubular film from the plurality of gathering fingers such that the tubular film contracts onto the object.