WO2000071308A1

WO2000071308A1 - A rotary die board and method for manufacturing same

Info

Publication number: WO2000071308A1
Application number: PCT/US2000/014664
Authority: WO
Inventors: Byung-Jun Song
Original assignee: Sds Usa, Inc.
Priority date: 1999-05-26
Filing date: 2000-05-26
Publication date: 2000-11-30
Also published as: JP2000334693A; KR20000074843A; AU5169300A

Abstract

A rotary die-board (35) having a curved cutting blade (40) and a manufacturing method thereof. A rotary die-board (35) comprises a supporting unit (30) for rotating on an object, such as a carton board, and a curved cutting blade (40) formed from a single, continuous piece of cutting blade material (such as steel rule), which is installed on a surface of the supporting unit (30). The cutting blade (40) is constructed by first folding the single, continuous piece of cutting blade material into a predetermined shape. One or more curved portions (44a, 44b, 44c) of the folded cutting blade may be formed to fit a curved surface of the supporting unit (30). A curved portion (44c) is formed by cutting a plurality of notches (12) along the bottom edge of the portion (44c) of the cutting blade (40) to be curved. The curved portion (44c) is then formed by applying a force to the sides of each notch (12) so as to squeeze the sides of each notch (12) closer together. This squeezing process causes the notched portion to curve. Therefore, a cutting blade (40) having one or more curved portions (44a, 44b, 44c) and/or straight portions (42a, 42b) can be constructed from a single, continuous piece of cutting blade material.

Description

A ROTARY DIE BOARD AND METHOD FOR MANUFACTURING SAME

BACKGROUND

1. Technical Field

The present invention relates generally to a rotary die board and, in particular, to a rotary die board comprising a die frame (supporting body) having a curved surface and a cutting blade, constructed from a single body, having one or more portions that are curved to fit the curved surface of the die frame, as well as a method for constructing a cutting blade for use with a rotary die board.

2. Description of Related Art

In general, a die board is an apparatus comprising a die body (or "supporting body") and a cutting blade that is bent into predetermined shape and installed on the die body. The cutting blade may be constructed by bending steel rule (which is a type of metal that is flexible and comprises a sharpened edge) into a desired shape. A cutting blade may be referred to as "steel rule die" , "steel rule" or "ribbon stock" by those of ordinary skill in the art . With the steel rule die being installed and held in place in the die body, the die board can then be pressed against an object with the appropriate force to cut an object into the predetermined shape of the steel rule die and/or generate folding lines in the object in the predetermined shape . By way of example, a cardboard box may be made from a flat piece of cardboard by pressing, for example, a planar die board against the piece of cardboard with sufficient force so that the sharpened edge of the steel rule die cuts the cardboard into the predetermined shape of the steel rule die. In addition, folding lines can be made in the flat piece of cardboard by pressing a die board against the cardboard piece with the appropriate force so that the sharpened edge of the steel rule die penetrates the cardboard to a predetermined depth to form folding lines conforming to the predetermined shape of the steel rule die. Thereafter, the cut cardboard piece may be folded to form a cardboard box.

Besides planar die boards, a rotary die board may be used for cutting an object. In general, a rotary die board comprises a die body (or roller) with a curved surface and a steel rule die that is made, e.g., from separate pieces wherein some of the pieces are curved to conform to the curvature of the die body. The rotary die board is rolled over an object that is placed on a board while applying sufficient force for the sharpened edge of the steel rule die to cut the object.

With a planar die board, the steel rule die is bent in only two dimensions. With a rotary die board, however, the steel rule die is bent in three-dimensions to fit the rotary die board. That is, in addition to being folded in two-dimensions, a steel rule die for a rotary die board is bent in a third dimension to conform to and fit the curved surface of the supporting body of the rotary die-board on which the steel rule die is installed. Conventionally, one method for making a curved steel rule die for a rotary die board involves forcibly bending (i.e., squashing) the steel rule die to fit to the curved surface of the supporting body of the rotary die board. Alternatively, another method involves cutting one side of the steel rule die to conform with the curvature of the surface of the supporting body, so that the steel rule die can be fit to the curved surface of the supporting body of the rotary die board. There are disadvantages associated with these conventional methods in that, e.g., there are difficulties in constructing a rotary die-board having a steel rule die that is formed by squashing or cutting to fit the curved surface of the supporting body of the die-board. As a result, such conventional methods result in lower productivity and increased production costs.

Another conventional method for forming the steel rule die of a rotary die board includes constructing the steel rule die with a plurality of separate pieces of steel rule comprising one of more straight pieces and curved pieces of steel rule. This method typically results in gaps that are formed between the separate pieces of the steel rule die. Consequently, this method can result in a rotary die-board having inferior cutting precision, which may cause improper cutting of an object or damage to the die-board.

Accordingly, an improved and efficient method for constructing a steel rule die for use with a rotary die board is highly desirable. SUMMARY OF THE INVENTION

In one aspect of the present invention, a rotary die board comprises a supporting unit having a curved surface and a cutting blade (e.g., steel rule die) that is constructed from a single, continuous piece of cutting blade material (e.g., steel rule ) and installed on the supporting unit. The cutting blade comprises one or more curved portions that are curved to fit the curved surface of the supporting body. In another aspect of the present invention, a method for constructing a cutting blade for a rotary die board comprises the steps of folding a cutting blade into a predetermined shape, and processing a portion of the cutting blade to form at least one curved portion that conforms to a curvature of a surface of a supporting body of the die board.

In yet another aspect, the step of processing the cutting blade to form a curved portion comprises the steps of forming a plurality of notches in the cutting blade along a bottom edge opposite a cutting edge of the portion of the cutting blade to be curved, and then for each notch as necessary, applying a force to each side of the notch so as to squeeze the sides of the notch closer together. The process of applying the force comprises the steps of griping both sides of the notch at a location near the bottom edge of the cutting blade, and applying an opposite force to each of the sides.

Advantageously, a cutting blade that is constructed in accordance with the present invention for use with a rotary die board is readily installed in the rotary die board and provides improved precision and productivity. These and other aspects, features and advantages of the present invention will be described and become apparent from the following detailed description of preferred embodiments, which is to be read in connection with the accompanying drawings .

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view of a folded cutting blade for use in a rotary die board according to an embodiment of the present invention; Figs. 2A through 2C illustrate a method for forming a curved portion of a cutting blade according to one aspect of the present invention; and

Fig. 3 is a perspective view of a preferred embodiment of a rotary die board according to the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention is directed to a rotary die board comprising a supporting unit having curved surface and a cutting blade that is installed on the supporting unit, wherein the cutting blade is constructed from a single, continuous piece of cutting blade material or stock having one or more curved surfaces that are curved to fit to the curved surface of the supporting unit. Although the cutting blade of the rotary die board may be made from any suitable rigid material, the cutting blade is preferably made from steel rule (therefore, the cutting blade may be referred to as a "steel rule die") . The steel rule die comprises one or more curved portions that are curved to fit the curved surface of the supporting body. As described in detail below, the curved portion (s) of the steel rule die are formed by cutting notches along a bottom edge (i.e., the edge opposite the sharpened edge or cutting edge) of the portion of the steel rule to be curved. Then, for each notch as necessary, an appropriate force is applied to the sides of the notch so as to squeeze the sides of the notch closer together by a desired amount.

By way of example, Fig. 1 illustrates a perspective view of a single, continuous piece of steel rule 10 folded in two dimensions, which may be used for constructing a steel rule die for use in a rotary die board according to an embodiment of the present invention. Fig. 2 illustrates a process of bending a notched portion of the steel rule to form a curved portion of the steel rule die. Fig. 3 illustrates a rotary die board 35 comprising a steel rule die 40 that is installed on a supporting unit 30, wherein the steel rule die is constructed from the single, continuous piece of steel rule 10 (Fig. 1) using the process of Fig. 2.

In particular, a steel rule die for use in a rotary die board may be formed by folding a straight piece of steel rule into a predetermined shape based on the desired shape of an object to be cut. By way of example with reference to Fig. 1, a folded piece of steel rule 10 is illustrated as comprising portions XI and X2 arranged along a first direction and portions Yl, Y2 , and Y3 arranged in a second direction transverse to the first direction. Each portion Yl , Y2 and Y3 has a respective body portion 11a, lib, and lie, as well as a plurality of notches 12 formed along the bottom edge (opposite the sharpened edge) of the steel rule. The notches 12 are formed in the body portions 11a to lie by cutting a predetermined shape along the appropriate edge of the portions Y1-Y3 (it is to be understood that the notches may be cut into the steel rule either prior to or after the steel rule is bent) . While the portions Yl to Y3 are curved to fit to a curved surface of the supporting unit 30, the portions XI and X2 are not curved (as explained in detail below with reference to Fig. 3) . Figs. 2A-2C illustrate a method according to one aspect of the present invention for bending a portion of the single, continuous piece of steel rule to form a curved portion of the steel rule die. It is to be appreciated that each of the portions Y1-Y3 of the piece of steel rule 10 (Fig. 1) may be curved to fit to a curved surface of a supporting unit of a rotary die-board using the method illustrated in Figs. 2A through 2C.

In particular, a curved portion Y' of a steel rule die comprising a body portion 11' having three notches 22, 24, and 26 along one side of a body portion 11' represents, for example, the transformation of side Yl (Fig. 1) to Y' . This transformation may be performed by applying a force to the bottom portions of the sides of each notch 22, 24 and 26 so as to squeeze the sides together and decrease the distance between the sides of the notch by a desired amount. For instance, referring to Fig. 2A, the bottom portions of the sides of notch 22 are squeezed together by applying an appropriate force to both sides of the first notch 22 in opposite directions as indicated by the arrows. Next, referring to Fig. 2B, the bottoms portion of both sides of a second notch 24 are squeezed together by applying an appropriate force to both sides of the second notch 24 in opposite directions as shown by the arrows. Next, referring to Fig. 2C, the bottoms portion of both sides of a third notch 26 are squeezed together by applying an appropriate force to both sides of the notch 26 in opposite directions as shown by the arrows .

Advantageously, by forcing together the sides of the notches 22, 24 and 26, the portion Yl will bend to form the curved portion Y' . Preferably, this process is performed for each notch associated with a given portion (Yl, Y2 , Y3) . It is to be appreciated that by performing this process for each portion (Yl, Y2 , Y3) , the folded single piece of steel rule 10 (Fig. 1) may be transformed, for example, into the steel rule die 40 as shown in Fig. 3 having curved portions 44a, 44b, and 44c, as well as the straight portions 42a and 42b.

It is to be understood that although the above process is described by squeezing the notches in the order of notch 22, 24 and 26, the process may be performed in random order with respect to the notches 22, 24, 26. It is to be further appreciated that the process depicted in Fig. 2 may be performed manually using any suitable tool or machine that includes a mechanism to grip the sides of a given notch and squeeze them closer together. In addition, such process may be performed by an automated system that provides a mechanism to grip both the sides of a given notch and apply a predetermined force to curve the portion in accordance with a curvature of the supporting body . Referring now to Fig. 3, a diagram illustrates a perspective view of a rotary die board according to an exemplary embodiment of the present invention. The rotary die board 35 comprises a cylindrical supporting unit 30 on which the steel rule die 40 is installed. In the exemplary embodiment, the steel rule die 40 is formed from the single, continuous piece of steel rule 10 as described above. As illustrated, the portions Yl , Y2 , Y3 of the single piece of steel rule 10 are bent using the process described above to generate the curved portions 44a, 44b, 44c, respectively, of the steel rule die 40. The curved portions 44a, 44b, 44c are curved to conform to and fit the curved surface of the cylindrical supporting unit 30. The steel rule die 40 is also folded in accordance with a predetermined shape of an object to be cut. Thus, the steel rule die 40 with a predetermined shape is installed on the surface of the supporting unit 30. In the exemplary embodiment of Fig. 3, during installation of the steel rule die 40, the straight portions 42a and 42b are substantially aligned along an axial direction through the center of the supporting unit 30, and the curved portions 44a to 44c are arranged along a direction of the curved surface of the supporting unit 30.

Accordingly, as shown in Fig. 3, a rotary die board according to an embodiment of the present invention may be constructed using a cylindrical shaped supporting unit 30 and a steel rule die 40 made from a single, continuous piece of steel rule that is processed to fit to the curvature of the supporting unit 30. The exemplary rotary die board 35 illustrated in Fig. 3 may be used to cut an object, such as a carton board, in a predetermined shape by rolling the die board 35 over the object so that the straight portions 42a, 42b and the curved portions 44a, 44b, 44c of the steel rule die 40 come into contact with the object so closely as to cut the object in a predetermined shape and in a predetermined depth.

It is to be appreciated that the present invention provides a method for constructing a steel rule die that is curved to fit the curvature of a supporting body. A steel rule die that is constructed in accordance with the teachings herein may be readily installed on a supporting body and provides improved cutting precision. A method for constructing a steel rule die for a rotary die board according to one aspect of the present invention comprises the following steps. The initial step involves folding a single, continuous piece of steel rule into a predetermined shape of an object to be cut. Then, a desired portion of the folded piece of steel rule is processed to form a curved portion that may readily fit to a curvature of the supporting body on which the steel rule die is installed. In one aspect of the invention, this processing step for forming a curved portion of the steel rule die is performed by cutting a plurality of notches along the bottom edge (opposite the cutting edge) of the portion of steel rule to be curved. The portion of the steel rule having the notches is then bent (curved) by squeezing together the bottom portion of the sides of a given notch to decrease the distance between the sides of the notch by a desired distance (and repeating this process for each notch) . As indicated above, the notches may be formed in the single piece of steel rule prior to the folding step. The resulting steel rule die (formed from a single, continuous piece of steel rule) having one or more curved portions is then installed on the supporting unit using any suitable conventional method known in the art. The rotary die board can then be rolled/rotated over the object being cut. As indicated above, the supporting unit may have a cylindrical shape. In such a case, the steel rule die may comprise straight portions (not curved) that are installed on the supporting unit in an axial direction, as well as curved portions that are installed on the supporting unit in a traverse direction.

As described above, because the steel rule die for a rotary die board may be readily formed by forming and bending the notches in the steel rule, a rotary die board constructed in accordance with the teachings herein may advantageously reduce working hours and improve productivity. In addition, since the steel rule die is made from a single piece of steel rule, the present invention provides an advantage over conventional methods where the rotary die board comprises, for example, a steel rule die that is constructed using separate straight pieces of steel rule that are individually bent (curved) and installed on the supporting body. Indeed, a rotary die board comprising a steel rule die made from a single, continuous piece of steel rule according to the present invention provides increased strength by eliminating the gaps that are formed between the separate curved and straight pieces comprising the steel rule die using the conventional rotary die boards. Moreover, increased precision in cutting objects (such as cardboard) is realized by eliminating such gaps. Another advantage associated with the present invention is that it provides a fast and efficient method of producing various shapes and configurations of steel rule dies for rotary die boards, thereby affording mass production and a reduction in production cost.

Although illustrative embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the present invention is not limited to those precise embodiments, and that various other changes and modifications may be affected therein by one skilled in the art without departing from the scope or spirit of the invention. For example, a steel rule die constructed using the method described herein may comprise any number of curved portions and/or straight portions. In addition, the amount, size and shape of the notches that are formed in the steel rule may vary depending on, e.g., the amount of bending required (i.e., degree of curvature) . Furthermore, a rotary die board may comprise a steel rule die comprising two or more components where each component is formed using the method described herein (e.g., a steel rule die comprising two separate components each made from a single, continuous piece of steel rule and having any number of straight and curved portions) . All such changes and modifications are intended to be included within the scope of the invention as defined by the appended claims .

Claims

WHAT IS CLAIMED IS:

1. A rotary die board comprising: a supporting body comprising a curved surface; and a cutting blade installed on the curved surface of the supporting body, wherein the cutting blade comprises a continuous piece of cutting blade material having at least one curved portion that conforms to the curved surface.

2. The rotary die board of claim 1, wherein cutting blade material comprises steel rule.

3. The rotary die board of claim 1, wherein the at least one curved portion comprises a plurality of notches formed along a bottom edge of the curved portion.

4. The rotary die board of claim 3, wherein the notches are processed to form the at least one curved portion.

5. The rotary die board of claim 3 , wherein the cutting blade comprises at least one straight portion.

6. The rotary die board of claim 5, wherein the supporting unit comprises a cylindrical shape.

7. The rotary die board of claim 6, wherein the at least one straight portion is installed on the supporting body along an axial direction of the cylindrical shape, and wherein the at least one curved portion is arranged substantially conforming to a curved surface of the supporting body.

8. A method for constructing a cutting blade for a rotary die board, comprising the steps of: folding a cutting blade into a predetermined shape; and processing a portion of the cutting blade to form at least one curved portion that conforms to a curvature of a surface of a supporting body of the die board.

9. The method of claim 8, wherein the step of processing comprises the steps of : forming a plurality of notches in the cutting blade along a bottom edge of the portion of the cutting blade to be curved; and applying a force to each side of at least one notch so as to squeeze the sides of the notch closer together.

10. The method of claim 9, wherein the step of applying a force comprises the steps of : griping both sides of the notch at a location near the bottom edge of the cutting blade; and applying an opposite force to each of the sides.

11. A method for constructing a rotary die board, comprising the steps of: providing a supporting body comprising a curved surface; folding a cutting blade into a predetermined shape; processing a portion of the cutting blade to form at least one curved portion that conforms to the curved surface of the supporting body; and installing the cutting blade on the supporting body.

12. The method of claim 11, wherein the step of processing comprises the steps of : forming a plurality of notches in the cutting blade along a bottom edge of the portion of the cutting blade to be curved; and applying a force to each side of at least one notch so as to squeeze the sides of the notch closer together.

13. The method of claim 12, wherein the step of applying a force comprises the steps of: griping both sides of the notch at a location near the bottom edge of the cutting blade; and applying an opposite force to each of the sides.

14. The method of claim 11, wherein the processing is performed one of manually and using an automated system.

15. The method of claim 11, wherein the supporting body is cylindrical shaped.

16. The method of 15, wherein the step of installing comprises the step of attaching the cutting blade to the supporting body such that the at least one curved portion is placed conformingly along a curved surface the cylindrical supporting body.

17. The method of claim 16, wherein the cutting blade has at least one straight portion, and wherein the at least one straight portion is substantially aligned along a central axis of the cylindrical supporting body.