US-12617647-B2 - Adjustable shingle to facilitate stacking

US12617647B2US 12617647 B2US12617647 B2US 12617647B2US-12617647-B2

Abstract

A system for conveying blanks to a stacker creates a big enough time gap between a last blank of a current stack and the first blank of the next stack to allow the stacker to discharge the current stack without interrupting the feed of new sheets for the next stack.

Inventors

Charles D. Rizzuti

Assignees

GEO. M. MARTIN COMPANY

Dates

Publication Date: 20260505
Application Date: 20231027

Claims (20)

1 . An apparatus for conveying and stacking, comprising: a first conveyor, the first conveyor is configured to move blanks; a second conveyor downstream from the first conveyor, the second conveyor is configured to move blanks; a stacker downstream from the second conveyor, the stacker is configured to create stacks of blanks, each stack includes a first blank and a last blank such that a current stack includes a first blank of the current stack and a last blank of the current stack and a next stack includes a first blank of the next stack and a last blank of the next stack; and one or more processors connected to the first conveyor and the second conveyor, the one or more processors are configured to: decrease speed of the first conveyor in response to the first blank of the next stack landing on the first conveyor, and decrease speed of the second conveyor in response to all one or more blanks from a first sheet of the next stack no longer being on the first conveyor so that the stacker can accumulate and remove the current stack that includes the last blank of the current stack but does not include the first blank of the next stack.
2 . The apparatus of claim 1 , wherein: the one or more processors are configured to increase speed of the second conveyor in response to the first blank of the next stack landing on the first conveyor.
3 . The apparatus of claim 2 , wherein: the one or more processors are configured to decrease speed of the first conveyor in response to all one or more blanks from the first sheet of the next stack no longer being on the first conveyor.
4 . The apparatus of claim 3 , wherein: the first conveyor is configured to move blanks at a first speed; the second conveyor is configured to move blanks at a second speed; and the one or more processors are configured to: decrease speed of the first conveyor from the first speed to a third speed and increase speed of the second conveyor from the second speed to a fourth speed in response to the first blank of the next stack landing on the first conveyor, and decrease speed of the first conveyor from the third speed to the second speed and decrease speed of the second conveyor from the fourth speed to the second speed in response to all one or more blanks from the first sheet of the next stack no longer being on the first conveyor so that the stacker accumulates and removes the current stack that includes the last blank of the current stack but does not include the first blank of the next stack.
5 . The apparatus of claim 4 , wherein: the first blank of the next stack and the last blank of the current stack are both positioned on the first conveyor when the one or more processors decrease speed of the first conveyor from the first speed to the third speed and increase speed of the second conveyor from the second speed to the fourth speed in response to the first blank of the next stack landing on the first conveyor.
6 . The apparatus of claim 4 , wherein: the stacker is configured to accumulate and remove the next stack after the stacker accumulates and removes the current stack.
7 . The apparatus of claim 4 , wherein: the first conveyor is configured to shingle blanks received at the first conveyor; and the second conveyor is configured to shingle blanks received at the second conveyor.
8 . The apparatus of claim 4 , wherein: the first conveyor is configured to shingle blanks received at the first conveyor at a first shingle distance in a first mode; the first conveyor is configured to move sheets at the first speed in the first mode; and the second conveyor is configured to move sheets at the second speed in the first mode.
9 . The apparatus of claim 8 , wherein: the first conveyor and the second conveyor are configured to transition to a second mode in response to the first blank of the next stack landing on the first conveyor; the first conveyor and the second conveyor are configured to transition to a third mode in response to all one or more blanks from the first sheet of the next stack no longer being on the first conveyor; the first conveyor is configured to transport sheets at the third speed in the second mode; the second conveyor is configured to transport sheets at the fourth speed in the second mode; and in the second mode, the first conveyor is configured to shingle blanks received at the first conveyor at a second shingle distance and the second conveyor is configured to shingle sheets received at the second conveyor at a third shingle distance, the second shingle distance is smaller than the first shingle distance, the third shingle distance is larger than the first shingle distance.
10 . The apparatus of claim 4 , further comprising: a set of snubbing wheels positioned above the second conveyor at the entrance of the second conveyor.
11 . The apparatus of claim 10 , further comprising: a group of snubbing wheels positioned above the first conveyor at the entrance of the first conveyor.
12 . The apparatus of claim 4 , further comprising: a sheet feed sensor connected to the one or more processors, the sheet feed sensor is configured to indicate presence of a sheet at a rotary die cutter upstream from the first conveyor, one or more processors are configured to use the indications of presence of a sheet in combination with length and speed of the first conveyor and the second conveyor to track position of the first blank of the next stack.
13 . The apparatus of claim 4 , further comprising: a layboy positioned upstream from the first conveyor, the layboy receives the sheets from a rotary die cutter, the layboy is configured to transport blanks to the first conveyor and remove scrap from the blanks, the first conveyor is configured to transport blanks to the second conveyor, the second conveyor is configured to transport blanks to the stacker, the rotary die cutter creates blanks from sheets.
14 . The apparatus of claim 4 , wherein the one or more processors are further configured to: in response to the first blank of the next stack reaching an end of the second conveyor before the stacker is ready for the first blank of the next stack, stop the second conveyor; and in response to the stacker accumulator extending, run the first conveyor at the first speed and run the second conveyor at the second speed.
15 . The apparatus of claim 4 , wherein: the first conveyor and the second conveyor include separate motors and separate belts driven by wheels that are actuated by the respective separate motors.
16 . The apparatus of claim 1 , wherein: the first conveyor is configured to move blanks at a first nominal speed; the second conveyor is configured to move blanks at a second nominal speed; and the one or more processors are configured to: increase speed of the first conveyor when a predetermined number of blanks prior to the first blank of the next stack have landed on the first conveyor, decrease speed of the first conveyor in response to the first blank of the next stack landing on the first conveyor, increase speed of the second conveyor and decrease speed of the second conveyor in response to a last blank of the current stack no longer being on the first conveyor, run the second conveyor at the second nominal speed in response to all one or more blanks from a first sheet of the next stack no longer being on the first conveyor, and slow down the second conveyor in response to the last blank of the current stack being off the stacking conveyor so that the stacker accumulates and removes the current stack that includes the last blank of the current stack but does not include the first blank of the next stack.
17 . The apparatus of claim 16 , wherein the one or more processors are further configured to: in response to the first sheet of the next stack reaching an end of the second conveyor before the stacker is ready for the first blank of the next stack, stop the second conveyor; and in response to the stacker accumulator extending, operate the first conveyor at the first nominal speed and the second conveyor to the second nominal speed.
18 . The apparatus of claim 16 , wherein: the first conveyor is configured to shingle blanks received at the first conveyor; the increasing speed of the first conveyor when a predetermined number of blanks prior to the first blank of the next stack have landed on the first conveyor comprises increasing the shingle distance of blanks that are shingled by the first conveyor; and the decreasing speed of the first conveyor in response to the first blank of the next stack landing on the first conveyor comprises decreasing the shingle distance of blanks that are shingled by the first conveyor.
19 . The apparatus of claim 16 , wherein: the first blank of the next stack and the last blank of the current stack are both positioned on the first conveyor when the one or more processors decrease speed of the first conveyor in response to the first blank of a next stack landing on the first conveyor.
20 . The apparatus of claim 16 , further comprising: a sheet feed sensor connected to the one or more processors, the sheet feed sensor is configured to indicate presence of a sheet at a rotary die cutter upstream from the first conveyor, one or more processors are configured to use the indications of presence of a sheet in combination with length and speed of the first conveyor and the second conveyor to track position of the first blank of the next stack.

Description

BACKGROUND Manufacturers of corrugated paper products produce both foldable boxes which have been folded and glued at the factory and die cut flat sheets which may be used either in their flat state or folded into a desired shape. These will be referred to as folded boxes and flat boxes respectively. The term boxes alone can refer to both folded and flat boxes. Both the folded boxes and the flat boxes are produced by converting machinery which processes corrugated sheet stock produced by machinery known as a Corrugator. The corrugated sheet stock is corrugated material cut to a specific size with optional scoring. Scoring is the intentional crushing of the corrugated flutes in order to allow folding of the corrugated material. However, the corrugated sheet stock has not been cut or notched to the detail typically required to produce the final foldable boxes or the flat boxes. For purposes of this document, the corrugated sheet stock shall be referred to as sheets. The term sheets can also be used to refer to similar or analogous materials formed into sheets. Often customized printing is required on boxes which may be done by using a preprinted material integrated into the corrugated sheet stock on the Corrugator, using flexographic printing during the converting process or applying ink or labels post converting through various techniques. During the converting process, the sheets are transformed into a box by performing additional cutting and optionally adding scoring and/or printing. There are multiple possible purposes for the additional cutting of the sheets. Many of these cutting operations will result in pieces of the sheets being completely separated from the final box. These pieces are, in general, referred to as scrap. As the boxes are produced they are aggregated into stacks of the boxes which in turn are sold or transported elsewhere. There are multiple methods by which the cutting of the sheets may be accomplished during the converting process. One example method for cutting sheets is known as rotary die cutting. A typical configuration of a rotary die cutter, known as rule and rubber, uses a pair of cylinders where the lower cylinder, known as the anvil, is covered in a firm but soft rubber material and the top cylinder is mounted with a die board. The die board is normally a curved plywood base in which embedded are a customized set of steel rules, which protrude from the plywood base and when rotated with the anvil will cut and score the corrugated sheet stock into the final desired box. The input to the rotary die cutter are the sheets of corrugated sheet stock. The rotary die cutter can cut a sheet into multiple smaller sheets, referred to herein as blanks. The sheets may be cut in the cross-machine direction in one or more locations to create two or more boxes in the through-machine direction. These are referred to as Ups. The sheets may also be cut in the through-machine direction in one or more locations to create two or more boxes in the cross-machine direction. These are referred to as Outs. Ups and Outs are both examples of blanks. After the rotary die cutter, one or more apparatus transport the blanks using one or more means of conveyance to a stacker to create stacks of blanks that can be provided to a customer or other entity. When the stacker has aggregated enough blanks to have a full stack, that full stack must be removed from the stacker. To allow time for the system to remove the full stack, prior art systems include feed interrupt time during which no sheet is input to the rotary die cutter to allow a gap between blanks at the end of a stack so that the stacker has time to remove the full stack from the stacker. However, including feed interrupt time reduces the throughput of the box making system. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 depicts a side view of a system for making boxes. FIG. 2 describes sheets and blanks. FIG. 3A depicts stacks of blanks. FIG. 3B depicts stacks of blanks. FIG. 4 depicts a perspective view of a portion of the system of FIG. 1. FIG. 5 depicts a perspective view of a portion of the system of FIG. 1. FIG. 6 depicts a simplified drawing of the system of FIG. 1. FIG. 7 depicts a simplified drawing of a portion of the system of FIG. 1. FIG. 8 is a flow chart describing one embodiment of a process for conveying blanks to the stacker that creates a big enough time gap between a last blank of a current stack and the first blank of the next stack to allow the stacker to discharge the current stack without interrupting the feed of new sheets. FIG. 9 is a flow chart describing one embodiment of a process for conveying blanks to the stacker that creates a big enough time gap between a last blank of a current stack and the first blank of the next stack to allow the stacker to discharge the current stack without interrupting the feed of new sheets. FIG. 10 depicts the stacker at four different conditions during the process of FIG. 9. FIGS. 11-16 depicts the