Pack alignment apparatus and methods using linear motor

Abstract

A system for forming and wrapping a plurality of stacks of sheet-like product is provided. The system includes a stack aligner for squaring up leading and trailing ends of the stack as well as sides of the stacks is provided. The stack aligner is also configured for controlling the position of the stacks along the stack travel path such that the stacks exit the stack aligner with tight positional tolerances for being fed to the stack wrapping arrangement.

Description

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS[0001]This patent application claims the benefit of U.S. Provisional Patent Application No. 61 / 879,236, filed Sep. 18, 2013, the entire teachings and disclosure of which are incorporated herein by reference thereto.FIELD OF THE INVENTION[0002]This invention generally relates to systems for forming wrapped stacks of sheet-like product, and particularly to an alignment apparatus for aligning stacks of sheet-like product prior to being wrapped into packs.BACKGROUND OF THE INVENTION[0003]Many sheet-like products such as, for example, napkins, facial tissues or paper towels are stacked and then wrapped for shipment. Many wrapping arrangements for wrapping the stacks process the stacks in a single-file orientation.[0004]The wrapping process and wrapping arrangements do not tolerate large variations in the spacing between stacks or variations in the shape / squareness of the stacks. As such, it is desirable to feed stacks to the wrapping arrangem...

AI Technical Summary

Benefits of technology

[0023]In one embodiment, the method is configured for accumulating stacks and the method includes increasing a number of accumulated stacks within the stack aligner.

[0024]In one embodiment, increasing a number of accumulated stacks within the stack aligner includes: feeding the stream of stacks to the stack aligner with a gap formed between adjacent stacks at an average feed rate but with an inconsistent gap width between adjacent stacks; and dispensing the stacks at an outlet end of the stack aligner at an average dispensing rate with a substantially equal spacing between adjacent stacks, the supply rate being greater than the dispensing rate.

[0027]In one embodiment, the average feed rate is less than the average dispensing rate such that a number of stacks within the stack aligner decreases. In one embodiment, the average feed rate is greater than the average dispensing rate such that a number of stacks within the stack aligner increases. Additionally, the system may switch between accumulating stacks and reducing the number within the stack aligner.

[0035]The stack aligner includes a plurality of paddles, a guide arrangement and a control arrangement. The paddles are configured for being inserted into the gap between adjacent stacks. The guide arrangement guides the paddles along a paddle travel path. The paddle travel path having a portion thereof that is coincident with a portion of the stack travel path. The control arrangement is configured to independently control the motion of the paddles along the paddle travel path. As such, the paddles can control the speed of the stacks through the coincident portion of the travel paths at different speeds. This allows for improved positional accuracy of the stacks as well as improving the squareness of the stacks.

Problems solved by technology

The wrapping process and wrapping arrangements do not tolerate large variations in the spacing between stacks or variations in the shape / squareness of the stacks.

As the speed of production of the stacks of sheet-like product increases it becomes more and more difficult to maintain the squareness of the stacks as well as the accuracy of the stacks along the stack travel path.

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