Cutting – Tool or tool with support – Joint or connection
Reexamination Certificate
1998-03-02
2001-04-03
Rada, Rinaldi I. (Department: 3724)
Cutting
Tool or tool with support
Joint or connection
C083S698110, C083S698710
Reexamination Certificate
active
06209436
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a cutting die for cutting corrugated board and other materials, and more particularly to a cutting die having a quick attach/detach mechanism for securing blades and rules to a die board that forms a part of the cutting die.
BACKGROUND OF THE INVENTION
In manufacturing corrugated board containers, sheets of corrugated board (blanks) are fed into a die cutting apparatus which typically trims, creases and cuts the corrugated board blank to form a corrugated board product that typically assumes a sheet form but which can be readily folded and shaped into a corrugated board container. Various types of die cutting assemblies are conventionally used. Basically, however, there are two types of die cutting assemblies—a rotary die type and a flat die type. In either case, the die assembly includes a die board. The die board is designed to perform a variety of functions on the corrugated board blanks. Typically, the die board is provided with cutting blades, scoring rules, and rubber scrap and product ejectors.
Cutting blades and scoring rules, which are collectively referred to herein as blades, are typically permanently or at least semi-permanently mounted in the die board. This, of course, means that they are not easily removed from the die board. Generally, in manufacturing die boards, a slit or groove is cut within the die board to conform with a blade or knife pattern design. The width of the slit or groove is specifically cut such that a strong frictional fit is achieved after the blade is pressed into the slit. In any event, the fit is sufficiently tight that the blade remains stationary or stable even through repeated and long die cutting operations.
For the most part, blades are not generally removed from die boards. If they are removed, the task becomes tedious, time-consuming and in the end very difficult and even costly. Because of this, blade adjustment or replacement is not routine. Most corrugated container manufacturers, when faced with blade replacement, will ship the cutting die back to the die maker for blade replacement.
However, there has been and continues to be a need for a die board that enables operators to quickly and easily exchange blades or adjust the position of existing blades within the die board. For example, one situation that comes to mind deals with the problem of forming nicks in blades. Nicks are small indentions made in the tip of blades for the express purpose of preventing the blade in the area of the nick from making a complete cut through the corrugated board blank. Thus, by appropriately nicking a blade, the operator can provide a very thin attachment between two adjacent corrugated panels, for example. This is a common practice in the corrugated board industry as nicks are widely used in certain situations to maintain a very thin and easily breakable connection between two panels of corrugated board.
Nick blades are provided in a variety of ways. Unfortunately, and all too often, die operators form nicks on existing blades with tools, such as a screw driver and hammer, while the blade is held within the die board. Such nicks are far from precise and the corrugated board product cut by such nick blades will reflect such. Moreover, once formed, these nicks are difficult to adjust, if adjustment can be made at all. From time to time, because of the nature of these die cutting assemblies, adjustments will have to be made. To replace or make such adjustments die operators may attempt to remove the nick blade or blades from the die board. But as pointed out above, this is a time-consuming and expensive procedure because to do so requires that the die cutting apparatus be shut down. Furthermore, the average die operator does not necessarily possess the skill or the training to efficiently remove and reinsert blades of any type within the die board.
SUMMARY AND OBJECTS OF THE INVENTION
The present invention presents a cutting die for cutting corrugated board that includes a quick attach/detach blade securing mechanism. By actuating the blade securing mechanism, a blade can be quickly and easily removed from a die board that forms a part of the cutting die, and a replacement blade can likewise be quickly and easily inserted into the die board.
In one embodiment of the present invention, a method is disclosed for securing a blade in the die board by forming a first slit or groove in the die board for receiving a blade. A second slit or groove is formed in the die board adjacent the first slit that retains the blade. The slit for retaining the blade is effectively open and closed by spreading and releasing the second slit. By spreading the second slit, a portion of the die board extending between the two slits is effectively pushed or urged towards the first slit. This results in the first slit effectively closing about the blade and securely locking the blade in place. To remove the blade, the second slit is relaxed or returned to its normal unspreaded state, resulting in the first slit assuming an open or unlocked mode.
In this embodiment, there is provided a bore formed in the die board adjacent the second slit. Disposed within the bore is a rotary cam lock that is rotatable between locked and unlocked positions. To lock the blade within the first slit, the rotary cam lock is rotated such that a cammed surface of the lock is turned into engagement with one side of the second slit, causing the slit to be spreaded and in the process resulting in the first slit being closed about the blade therein. By rotating the cam lock from the locked position to the unlocked position results in the second slit assuming a relaxed or unspreaded state. This effectively opens or releases the first slit enabling the blade therein to be easily removed therefrom.
In another embodiment of the present invention, an insert is secured within the second slit. The insert includes a bearing strip against which the rotary cam lock engages when the same assumes a locked position. That is, the insert includes a bearing strip that extends through the second slit and is disposed adjacent the rotary cam lock. Projecting from the bearing strip is at least one retaining tab that is aligned with the adjacent bore and functions to assist in retaining the rotary cam lock within the bore.
In yet another embodiment, the present invention entails a die board having a bore formed in the die board adjacent a slit that retains a blade therein. The bore is opened or exposed to the slit and the blade. Disposed within the bore is a rotary locking device that is rotatable between a locked and unlocked position. In the locked position, the rotary lock engages a side portion of the blade and presses the blade into engagement with one side of the slit that retains the blade. Thus the blade is effectively wedged or locked between the rotary locking device and one side of the slit that retains the blade.
It is therefore an object of the present invention to provide a die board for cutting corrugated board with a quick attach/detach mechanism for securing blades within the die board.
A further object of the present invention is to provide a die board of the character referred to above that will enable die operators to quickly and easily exchange or adjust blades within the die board.
Still a further object of the present invention is to provide a quick attach/detach blade securing mechanism for a die board that can be actuated without disturbing adjacent scrap or product ejector rubber.
REFERENCES:
patent: 969371 (1910-09-01), Helm
patent: 3941038 (1976-03-01), Bishop
patent: 5029505 (1991-07-01), Holliday
patent: 5275076 (1994-01-01), Greenwalt
patent: 5890410 (1999-04-01), Hinojosa
patent: 000690835 (1964-07-01), None
Ashley Boyer
Coats & Bennett PLLC
Container Graphics Corporation
Rada Rinaldi I.
LandOfFree
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