Sheet feeding or delivering – Delivering – Multiple discharge
Reexamination Certificate
2002-09-25
2004-09-07
Walsh, Donald P. (Department: 3653)
Sheet feeding or delivering
Delivering
Multiple discharge
Reexamination Certificate
active
06786484
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed generally to a sheet inverter. More particularly, the present invention is directed to a sheet inverter useable to invert flexible sheets. Most specifically, the present invention is directed to a sheet inverter for repositioning sheets of flexible corrugated paperboard stock useable in the fabrication of cartons. The corrugated sheets, which are typically printed, scored and slotted, are quite flexible and are positioned on a plurality of spaced belt conveyors which form a sheet stacker. The sheet inverter repositions these corrugated sheets of paperboard by inverting them during their conveyance on the sheet stacker and prior to delivery of the sheets to a sheet stack hopper. The sheet inverting can be accomplished on individual sheets. More typically, a plurality of stacked sheets will be inverted as a group. The sheet inverter utilizes a plurality of sheet inverting fingers which interdigitate with the spaced belt conveyors that support the printed, slotted and scored flexible corrugated paperboard sheets being inverted.
BACKGROUND OF THE INVENTION
A great number of products are packaged, by their manufacturers, for shipping and distribution in corrugated paperboard cartons or boxes. These corrugated paperboard boxes or cartons are typically supplied to their end user; i.e. the manufacturer of the products to be boxed and shipped, in a non-erected configuration. Clearly, it is not efficient to ship or transport fully set up or erected empty paperboard boxes from the box manufacturer to a product manufacturer, who will then fill these erected corrugated paperboard cartons with his product. Rather, these corrugated paperboard cartons are shipped to the end user in a non-erected configuration. The corrugated paperboard boxes arrive at the end user's facility each folded flat as a sleeve. Each carton's bottom and top flaps are usually then folded into place and glued or taped to complete the erection of the cartons immediately before their useage. These non-erected boxes are supplied to the end user by a corrugated box manufacturer.
The corrugated box manufacturer starts with a stack of sheets of corrugated paperboard which he obtains from a supplier of corrugated sheets. The overall size of each sheet has been determined by the box manufacturer or by the end user in accordance with the size of the intended corrugated box or carton. The corrugated paperboard sheets are received by the corrugated box manufacturer from the corrugated sheet supplier typically already provided with across-corrugation score lines. These score lines will, when combined with score lines added by the corrugated box manufacturer, define lines of fold that will typically cooperate with slots cut into the corrugated sheets by the box manufacturer. In some situations, the corrugated sheets received from the supplier are not scored. In those instances, the box manufacturer must score, slot and print the corrugated sheets.
The corrugated sheets are slotted to create the carton's side panels and end flaps, and are also printed with suitable graphics, as determined by the end user. A machine, typically referred to as a printer-slotter is used for this purpose. The printer-slotter is akin to a rotary printing press and includes one or more pairs of cooperating printing rollers with the number of printing roller pairs being equal to the number of colors that can be printed. The printer-slotter also is provided with multiple pairs of cooperating scoring rollers and slotting knives. The corrugated paperboard sheets are placed, in a stack, on an infeed table of the printer-slotter. As these sheets travel individually through the printer-slotter, each is first printed and scored and is then slotted. The specific graphics printed on the sheets, the location of the slots, the scoring and the cut-outs cut into the sheets can be changed.
The printed, scored and slotted sheets are then fed to an intermediate, driven conveyor, typically referred to as a lay boy. The lay boy accumulates and transfers printed, scored and slotted corrugated paperboard box blanks to a sheet stacker and to a sheet stack hopper for collection and stacking.
A wide variety of printer-slotters are available to corrugated box manufacturers. All can be categorized by the location of their printing plates. They are thus either “top” printers or “bottom” printers. The corrugated and now printed, scored and slotted box blanks exit the printer-slotter with their printed surfaces either face up or face down, dependent on the type of printer-slotter which the corrugated box manufacturer may have. Some larger manufacturers may have one or more of either type.
Once the corrugated sheets have been printed, scored and slotted, they are typically placed in a stack by operation of the lay boy, sheet stacker and sheet stack hopper referred to above. These printed and slotted sheets are then formed into non-elected boxes by the folding of each sheet into a sleeve-like configuration. The folded sheets are formed into sleeves by a joining step such as stitching or taping of the sheet ends. After the printed, scored and slotted flexible corrugated paperboard sheets have been formed into these sleeves, they are then again stacked and suitably bound and are then sent to their end user.
The sheets are turned into sleeves by a “joiner.” It is the function of the joiner to fold the sheets along their score lines and to join together the length and width panels of the partially finished box, to form the sleeves. A variety of joiners are available. Some of these form the printed, slotted and scored box blanks into non-elected sleeves by folding the length and width panels of the printed and slotted blanks down and in. Others fold the length and width panels of the blanks up and in. The printed, scored and slotted corrugated sheets provided to a joiner that fold down and in, are supplied with their printed side facing up, assuming that the printed graphics are intended to be situated on the exterior of the folded box. If the joiner folds up and in to form the intermediate sleeve, the printed, scored and slotted blanks must be situated on the joiner with their printed sides facing down.
If only a few printed, scored and slotted corrugated paperboard sheets were to be made into non-erected sleeves, the placement of the printed, scored and slotted sheets on the joiner in a print side up or print side down orientation would be a small task. However, in a corrugated box manufacturing plant, a substantial percentage of each day's output from the printer-slotter must be inverted to orient them properly for the joining step.
In the past, this inverting step has been done manually or by some makeshift arrangement. The inverting of stacks of sheets, if done manually, is quite likely to cause physical injury. It is a step that frequently requires the participation of two workers, who must leave other tasks to accomplish this one. Such manual sheet inversion places the workers at greater risk of physical injury, with its attendant health and disability costs. It also is very labor intensive and thus increases the cost of the finished product. Since the finished product is a non-erected shipping carton or container, there is a limit to the price that can be charged. All of these factors makes the need for a better, faster, more efficient and less expensive device for inverting flexible sheets of corrugated paperboard, having a wide range of sizes and weights, that much greater.
Several sheet inverting devices are known in the prior art. One of these uses a plurality of arms to invert drywall panels. The arms are provided with large rollers at their free ends. In use, a first group of arms and rollers extend underneath the leading edge of a drywall panel and raise the leading edge. A second set of arms and rollers catch the now trailing edge of the inverted panels and lowers the inverted panels onto the conveyor belt. This system is too slow for efficient use with a printer-slotter in a corrugated paperboard b
Bower Kenneth W
Jones Tullar & Cooper PC
Sebring Container Corp.
Walsh Donald P.
LandOfFree
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