Patent Application
20170028581
The present invention relates to rotary cutting dies designed to cut and score corrugated board that is used in making corrugated board boxes.
Rotary cutting dies are used to cut and score sheets of corrugated board to produce a die cut product that can be manipulated into boxes. Rotary cutting dies typically include a curved die board that is configured to mount on a die cylinder. When used, the die cylinder and die board are mounted adjacent an anvil and a nip is defined between the cylinder and the anvil. Sheets of corrugated board are fed into and through the nip and, in the process, the sheet of corrugated board is cut and scored to form the die cut product. Die boards commonly include product and scrap cutting blades, scoring rules, trim and scrap strippers and product ejectors for separating the die cut product from the cutting die.
A common problem with rotary cutting dies that operate on corrugated board is controlling the pressure exerted against the corrugated board by the product ejectors. If the pressure is too great, the die cut product is damaged. That is, if the pressure is too great, the flutes are crushed. This makes the resulting boxes weaker and hence the boxes possess less stacking strength and the crushed flutes have a negative impact on the appearance of the product.
On the other hand, if the pressure exerted by the product ejectors is too low, then this will impact the separation of the die cut product from the cutting die during the die cutting operation. That is, if the pressure is insufficient to dislodge or remove the cut die product from the cutting die, it follows that the product will continue with the cutting die and the die cutting operation will be seriously impacted.
There have been attempts at controlling the pressure exerted by the product ejectors. For example, there have been attempts at using softer elastomer ejectors. This has met with only limited success. Even so, the softer elastomer product ejectors can be expensive and that alone has discouraged the adoption of some softer product ejector elastomers. Another attempt at solving this problem has been to use a water jet cutter to cut openings in the product ejectors. This has not proven completely successful. There are still problems with the pressure being too great and resulting in damage to the die cut product. In addition, the use of laser cut product ejectors adds significant cost to cutting dies.
In some cases, product ejectors are required adjacent a cutting or scoring rule. This limits the options for dealing with this problem because, in conventional designs, the die board itself supports the scoring or cutting rule. Here, care must be taken not to incorporate a product ejector design that compromises or impairs the integrity of the die board adjacent areas that support the cutting or scoring rules.
Therefore, there has been and continues to be a need for an efficient and effective product ejector design that can be incorporated into a die board adjacent a scoring or cutting rule that does not compromise or impair the integrity of the die board in locations where the die board supports the cutting or scoring rule.
A rotary cutting die for cutting corrugated board includes a die board having an opening formed therein. A rule support structure, such as one or more ribs, is anchored to the die board and spans the opening. A scoring or cutting rule is supported by the rib. The scoring or cutting rule extends over at least a portion of the opening in the die board. At least one insert is secured to the die board and disposed in the opening of the die board. One or more product ejectors are secured to the insert in a position adjacent the scoring or cutting rule. The product ejector extends past the outer edge of the scoring or cutting rule when there is no load on the product ejector.
In one embodiment, there is provided a single insert that is disposed in the opening in the die board and wherein the single insert supports a plurality of product ejectors that are disposed on both sides of the scoring or cutting rule. In another embodiment, a plurality of inserts is secured in the opening in the die board and each insert supports at least one product ejector.
Other objects and advantages of the present invention will become apparent and obvious from a study of the following description and the accompanying drawings which are merely illustrative of such invention.
With further reference to the drawings, a rotary cutting die apparatus is shown therein and indicated generally by the numeral 30. As is appreciated by those skilled in the art, the rotary cutting die apparatus 30 is designed to receive sheets of corrugated board CB and to die cut the sheets of corrugated board to produce a die cut product. Further, the rotary cutting die apparatus 30 is designed to cut, score and, in most cases, remove scrap from areas of the product board. In the end, the rotary cutting die apparatus is designed to cut and condition the corrugated board CB such that the die cut product can be easily manipulated into a box configuration.
With particular reference to
Die board 42 is typically constructed of laminated plywood. Die boards, such as that illustrated in
The design of the die board 42 shown in
With reference to
Die board 42 is provided with a rule or blade support structure that spans opening 60. With reference to
Ribs 64 function to support a scoring or cutting rule in the opening 60. As seen in the drawings, there is provided a scoring or cutting rule 70 that extends over the ribs 64 at a generally 90° angle. Rule 70 in the case of the embodiments shown in the drawings includes a pair of notches 70A. See
To provide additional support for the scoring or cutting rule 70, there is provided a pair of supports 72 that sandwich the scoring or cutting rule. Supports 72, similar to rule 70, include notches 72A that enable the support 72 to be pressed downwardly onto the transverse ribs 64. Again, the notches 72A and the ribs 64 are dimensioned to yield a tight frictional fit between the ribs and supports. Ribs 64 prevent the cutting or scoring rule 70 and the support 72 from twisting or angling within the opening 60. The tight frictional fit that exists between the notches 70A and 72A and the ribs 64 generally serves to retain the cutting or scoring rule 70 and supports 72 in the opening 60. In addition, the cutting or scoring rule 70, supports 72, notches 70A and 72A, along with the rib 64 are dimensioned such that the lower edges of the cutting or scoring rule 70 and supports 72 engage the outer surface of the cylinder 40. See
Opening 60 is designed to receive and hold one or more inserts 80 for receiving and supporting product ejectors 84. In one embodiment, the embodiment depicted in
Note in the case of the embodiment shown in
Turning to
Secured to the inserts 80 is one or more product ejectors 84. The product ejectors 84 are constructed of resilient and compressible material and are designed to be compressed as the die cut product passes through the nip. As the die cut product exits the nip, the product ejectors 84 expand or extend to engage the die cut product and push the die cut product from the die board. Product ejectors 84 can assume various shapes. In the embodiments illustrated herein, the product ejectors 84 assume a generally parallelepiped shape. To secure the product ejector 84 into a respective insert 80, an end portion of the product ejector is glued to the bottom 80A of the insert 80. Thus, there is a second adhesive layer 86 that secures an inner end portion of the product ejector 84 to the bottom of the insert 80. See
In
Viewing assembly 100, it comprises a pair of side members, each side member being indicated generally by the numeral 102. Each side member 102 includes an outer flange 102A that is adapted to rest on the upper surface 42A of the die board. Flange 102A includes a series of screw openings 102B for accepting screws. Screws are secured downwardly through the screw openings 102B into the die board as shown in
Extending between the side members 102 and extending in parallel relationship thereto is a cutting or scoring rule 106. In the embodiment illustrated herein, the cutting or scoring rule 106 is notched to fit downwardly over the cross members 104. Other forms of intersecting or supporting the cutting or scoring rule 106 can be employed. In addition, the cutting or scoring rule 106 is sandwiched by a pair of supports 108 that are likewise notched to fit downwardly over the cross members 104. The cutting or scoring rule 106, as well as the supports 108, can be frictionally secured to the cross members 104. In addition, the scoring or cutting rule 106 and supports 108 can be secured by other means, such as weldment, to the cross members 104.
As seen in
There are many advantages to securing the product ejector 84 in the manner described herein. First, the inserts enable a secure connection to be made directly to the insert and indirectly to the die board. In addition, controlling the pressure exerted by the product ejector is facilitated by being able to utilize relatively long product ejectors. By employing inserts in the die board and positioning the bottom of the inserts close to the inner surface of the die board enables the product ejectors to assume relatively long lengths. Typically the die board is approximately ½″. By employing the inserts described herein, the product ejector can extend approximately ⅝″ above the outer surface of the die board. This enables a die manufacturer to selectively choose and use ejector material that will permit pressure to be controlled and will enable the product ejectors to efficiently eject die cut product without crushing and damaging the same.
The present invention may, of course, be carried out in other ways than those specifically set forth herein without departing from essential characteristics of the invention. The present embodiments are to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.
