Method for axial feeding of ribbon material and a stock of ribbon material coils for axial feeding

#The present invention relates generally to continuously supplying flexible raw material generally in the form of a web to a processing machine, and more particularly to a stock of ribbon material and methods for controlling twisting of the ribbon material fed to the processing machine.

#Conventional processing machines, such as those used to convert narrow ribbons of raw material into finished product, run most efficiently when a continuous feed of raw material is provided. If continuous feed of raw material is not maintained, the machine must be shut down to re-thread the ribbon material. Shutting down the machine negatively impacts the efficiency of the machine, especially machines used in high volume processes such as the production of feminine care products.

#Raw absorbent material used to produce feminine care products is initially manufactured as a web of absorbent material measuring one meter or more in width. The processing machine cannot process such a wide web, so the material is trimmed to form many ribbons of a more usable narrow width. The wide web is suitably scored or sheared to form the ribbons. Typically, the ribbons are then wound onto cores to form coils or “pancake slits”, so-called due to the fact they resemble pancakes when laid flat. Each coil has a thickness substantially equal to a width of the ribbon material, and each successive revolution or turn of ribbon substantially overlies the preceding revolution so that the coil is no thicker than the ribbon material is wide.

#FIG. 1 is a perspective view of a stock of coils connected according to one embodiment of the present invention;

#FIG. 2 is a perspective view of a stock of twenty coils;

#FIG. 3 is a plan view of an illustrative coil wound in a counterclockwise direction;

#Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

#Referring now to the drawings and in particular to FIG. 1, a stock of flexible ribbon material adapted for continuous axial feed to a processing machine (not shown) is generally designated by the reference numeral 11. The stock includes a first or upper coil 13, a second or middle coil 14 and a third or lower coil 15 spliced end-to-end as further described below. Each coil 13-15 is formed of ribbon material wound about a central axis 17 of the coil. Each coil has a sequence of turns (e.g., turns 18a-18h (FIG. 3) wound about the central axis 17. Although FIG. 3 shows eight turns, those skilled in the art will appreciate that the coil may include fewer and more desirably includes many more turns wound about the central axis 17. Each coil also includes a central end 19 at an inner-most turn 18a of the sequence of turns and an outer end 21 at an outer-most turn 18h of the sequence of turns. In general, the central end 19 is adjacent the central axis 17 and the outer end 21 is at an outer periphery of the coil. The ribbon material is sheared or “slit” from a wide roll (e.g., having a width of one meter or more) of absorbent raw material. The resulting coils 13-15 of one embodiment have a thickness 22 between about 20 mm and about 50 mm, desirably about 37 mm and a diameter 23 between about one meter and about two meters, e.g., 1.2 meters. Note that in one embodiment the thickness 22 of each coil is substantially equal to a width 25 of the ribbon and that each turn of ribbon substantially overlies the preceding revolution about the central axis. It will be understood that the thickness 22 and diameter 23 of the coil may be other than as described herein without departing from the scope of the present invention.

#The coils 13-15 of the stock 11 are sequenced by stacking the middle coil 14 on the lower coil 15 and the upper coil 13 on the middle coil. Note that the coils may be sequenced other than by stacking, e.g., they may be placed horizontally adjacent one another. In this embodiment, the coils are oriented so that each is wound in the same direction. Although all of the coils may be wound in a clockwise direction without departing from the scope of the present invention, in the embodiment shown in FIG. 1, all the coils are wound in a counterclockwise direction (as viewed from above the coils). As described more fully below, ends of the coils are then spliced such that at least some twists developed during axial ribbon feed of the upper coil 13 are removed during axial ribbon feed of the middle coil 14. In the embodiment shown in FIG. 1, the central end 19 of the upper coil 13 is spliced to the central end of the middle coil 14, and the outer end 21 of the middle coil is spliced to the outer end of the lower coil 15. The ends are suitably spliced such as by applying double-sided adhesive tape to one of the ends to be spliced and pressing the other end to be spliced on the tape so that the ends overlap. Other methods of splicing, such as applying adhesive directly to the ribbon may be used without departing from the scope of the present invention. Further, the ends may be lapped or butted without departing from the scope of the present invention.