Knife cylinder for a rotary die cutter

Abstract

 Object: To provide an economical knife cylinder of a rotary die cutter in which a cutter fitting plate is fixed quickly to the rotary die cutter and a non-operation time of machines required for the fixing is decreased and an operation time is increased, thereby a productivity is enhanced.
Construction: A knife cylinder of a rotary die cutter in which a knife cylinder (3) is provided on its cylindrical face with a cutter fitting plate (4) of a bent rectangular plate shape having an arcuate cross section bent along said cylindrical face, wherein a metal member (7) is provided on said cylindrical face extendingly in the axial direction of said knife cylinder (3) in engagement with a front end of said cutter fitting plate (4) and a right and left pair of circumferential directional metal members (8a, 8b) are provided on said cylindrical face extendingly in the circumferential direction in engagement with the right and left ends of said cutter fitting plate (4), thereby said cutter fitting plate (4) is fixed on said cylindrical face tri-directionally in engagement with each of said metal members (7, 8a, 8b).

Description

BACKGROUND OF THE INVENTION:

Field of the Invention:

[0001] The present invention relates to a knife cylinder of a rotary die cutter to be used for processing of corrugated boards etc.

Description of the Prior Art:

[0002] In manufacturing of corrugated board boxes, for example, a marking-off of a necessary shape or a punching process is carried out on a previously printed corrugated board by use of a rotary die cutter as shown in a front view and a side view of Fig. 3.

[0003] A rotary die cutter of this kind comprises, as shown in Fig. 3, a right and left pair of base frames 14a, 14b provided standingly in parallel and connected each other via an upper stay 12 and a lower stay 13 extending in the right and left direction respectively, and an anvil cylinder 2 and a knife cylinder 3 of a same diameter, supported each by a shaft and extending in the right and left direction at the upper portion and the lower portion respectively of both frames 14a, 14b. Both cylinders 2, 3 are engaged with each other so as to rotate synchronously in mutually opposite directions via gears 15, 16 fitted to an end on a same side of the respective shaft and via a gear driving means (not shown).

[0004] On the upstream side of both cylinders 2, 3, an upper and lower pair of transfer rolls 17a, 17b of a same diameter are provided to supply a corrugated board sheet 1 between both cylinders 2, 3.

[0005] A cutting knife 5 or a creaser knife etc. is fixed on the outer circumferential surface of the knife cylinder 3 via a cutter fitting plate 4, thereby the corrugated board sheet 1 transferred one by one by the transfer rolls 17a, 17b from a printing process which is a preceding process is applied with a necessary processing like a punching or a marking-off etc. by nipping rotations of the anvil cylinder 2 and the cutting knife 5 or the creaser knife fixed to the knife cylinder 3.

[0006] Next, a cutting function is described. Generally, as a basic structure of a rotary die cutter portion to do cutting of a corrugated board sheet to a necessary shape, there are two kinds of types as shown in Figs. 4 and 5.

[0007] The one shown in Fig. 4 is named a soft cutting type, wherein a knife cylinder 3 fixed with a cutting knife 5 on its outer circumferential surface via a cutter fitting plate 4 and an anvil cylinder 2 covered with a shock absorbing material 8 like a urethane rubber etc. on its outer circumferential surface are engaged with each other and a corrugated board sheet 1 is cut to a desired shape by the cutting knife 5 being pierced through the corrugated board sheet 1 and an edge of the knife encroaching upon the shock absorbing material 8 of the anvil cylinder 2.

[0008] The one shown in Fig. 5 is named a hard cutting type, wherein a knife cylinder 3 fixed with a cutting knife 5 on its outer circumferential surface via a cutter fitting plate 4 and an anvil cylinder 2 of an iron surface are engaged with each other and a corrugated board sheet 1 is cut to a desired shape by the cutting knife 5 coming in contact with, or being pressed with an appropriate pressing force to, the outer circumferential surface of the anvil cylinder 2.

[0009] Here, a setting of the cutter fitting plate 4 to fix the cutting knife 5 is described. In a knife cylinder portion shown in Fig. 6(A), a metal member 19 of a rectangular cross section extending in the axial direction is provided projectingly on the outer circumferential surface of the knife cylinder 3 and the cutter fitting plate 4 of a bent rectangular plate shape is positioned with its front end touching the metal member 19. Then, making use of screw holes 6 formed within the outer circumferential surface of the knife cylinder 3, flat head bolts 9 are screwed in so as to fix the cutter fitting plate 4 one by one to the direction of the rear end side.

[0010] However, in such setting structure of a cutter fitting plate 4, as shown in a development of Fig. 7, in order to maintain with a high accuracy a radius of rotation of the edge portion of the cutting knife 5 accompanying with rotations of the knife cylinder 3, it is necessary that a large number of screw holes 6 are provided vertically and horizontally at the cutter fitting plate 4, a large number of flat head bolts 9 for fixing are used and a fixing is made with a high density of fixing points.

[0011] Accordingly, in case of a replacement of the cutter fitting plates 4 accompanying with a change of orders, it takes not a little time for detachment and attachment of a large number of flat head bolts 9, which is a large factor to lower an operation rate of a die cutter. In recent years, there are many cases where a change of orders is frequently taken place in order to deal with multi-kind less quantity productions, hence a shortening of a re-setting time is an important object.

[0012] In Fig. 7 which shows a development of the corrugated board sheet 1 to be cut on the cutter fitting plate 4, the cutting knife 5 is fitted to the cutter fitting plate 4 in accordance with a cutting line shown in a line S, and a broken line K shows a marking line.

[0013] In the prior art as mentioned above, as a means to fix a cutter fitting plate fitted with a cutting knife to a knife cylinder of a rotary die cutter, such a construction is employed that screw holes formed within the outer circumferential surface of the knife cylinder are used and flat head bolts are inserted and screwed therein for tightening from the outer circumferential surface of the cutter fitting plate.

[0014] Accordingly, in order to maintain an accuracy of a rotating radius of the cutting knife or in order to enhance a tightening ability of the cutter fitting plate to the knife cylinder, a fixing by use of a large number of flat head bolts becomes necessary, hence not a little time is needed for detachment and attachment of bolts in case of a replacement of cutter fitting plates accompanying with a change of orders.

[0015] Further, as such changes of orders take place frequently, a non-operation time of machines increases and there is such a problem that a productivity cannot be enhanced.

SUMMARY OF THE INVENTION:

[0016] In view of the circumstances mentioned above, the present invention is disclosed with an object to provide an economical knife cylinder of a rotary die cutter wherein a cutter fitting plate is quickly fitted to a rotary die cutter, thereby a non-operation time of machines required for the fitting is decreased so that an operation time is increased, thus a productivity is enhanced.

[0017] According to the present invention which can dissolve the above-mentioned problems in the prior art, one feature is a knife cylinder of a rotary die cutter in which a knife cylinder is provided on its cylindrical face with a cutter fitting plate of a bent rectangular plate shape having an arcuate cross section bent along said cylindrical face, wherein a metal member is provided on said cylindrical face extendingly in the axial direction of said knife cylinder in engagement with a front end of said cutter fitting plate and a right and left pair of circumferential directional metal members are provided on said cylindrical face extendingly in the circumferential direction in engagement with the right and left ends of said cutter fitting plate, thereby said cutter fitting plate is fixed on said cylindrical face tri-directionally in engagement with each of said metal members.

[0018] Another feature of the present invention is a knife cylinder of a rotary die cutter wherein an upwardly inclined face is formed at each engaging end portion of said cutter fitting plate, a downwardly inclined face is formed at each engaging end portion of said metal members and each downwardly inclined face of said metal members presses each engaging upwardly inclined face of said cutter fitting plate, thereby said cutter fitting plate is fixed on said cylindrical face.

[0019] A further feature of the present invention is a knife cylinder of a rotary die cutter wherein said pair of circumferential directional metal members are formed as annular metal members to be fitted-in around said cylindrical face of the knife cylinder.

[0020] A still further feature of the present invention is a knife cylinder of a rotary die cutter wherein one of said pair of annular metal members is fitted-in fixedly around said cylinder face and the other is fitted-in detachably around said cylinder face.

[0021] A further feature of the present invention is a knife cylinder of a rotary die cutter wherein an engagement of said cutter fitting plate and each of said metal members is made via a metal element inbetween.

[0022] According to the present invention as so constructed, a front end and right and left ends of a cutter fitting plate fixed with a cutting knife can be fixed easily on a knife cylinder and yet, by a function of a front end positioning metal member and fixing rings, a floating of said cutter fitting plate can be prevented securely. Accordingly, the number of flat head bolts used for fixing a cutter fitting plate in the prior art can be greatly lessened.

[0023] Hence, a time required for a replacement of cutting knives or cutter fitting plates can be shortened greatly, and enhancement of an operation rate of machines becomes possible.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0024] In the accompanying drawings:

Fig. 1 shows a knife cylinder of a rotary die cutter of one preferred embodiment according to the present invention, wherein Fig. 1(A) is an entire perspective view, Fig. 1(B) is a transverse sectional view taken on line B-B in the direction of arrows of Fig. 1(A), and Fig. 1(C) is a longitudinal sectional view taken on line C-C in the direction of arrows of Fig. 1(A).

Fig. 2 is a development showing a cutter fitting plate of Fig. 1.

Fig. 3 is an entire view showing a die cutter in the prior art, wherein Fig. 3(A) is a front view and Fig. 3(B) is a side view.

Fig. 4 is a side view of cylinders of Fig. 3 of a soft cutting type.

Fig. 5 is a side view of cylinders of Fig. 3 of a hard cutting type.

Fig. 6 shows a knife cylinder of a rotary die cutter in the prior art, wherein Fig. 6(A) is an entire perspective view, Fig. 6(B) is a transverse sectional view taken on line b-B in the direction of arrows of Fig. 6(A), and Fig. 6(C) is a longitudinal sectional view taken on line C-C in the direction of arrows of Fig. 6(A).

Fig. 7 is a development showing a cutter fitting plate of Fig. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS:

[0025] One preferred embodiment according to the present invention is described with reference to figures. Fig. 1 shows a knife cylinder of a rotary die cutter of the preferred embodiment, wherein Fig. 1(A) is an entire perspective view, Fig. 1(B) is a transverse sectional view taken on line B-B in the direction of arrows of Fig. 1(A), and Fig. 1(C) is a longitudinal sectional view taken on line C-C in the direction of arrows of Fig. 1(A). Fig. 2 is a development of a cutter fitting plate of Fig. 1.

[0026] In the above figures, same numerals as those in Figs. 6 and 7 designate same components or parts respectively as those shown therein. Defferently from the conventional knife cylinder shown in Fig. 6, there are formed screw holes 6 only at two places of an outer circumferential face of a cutter fitting plate 4 of a knife cylinder 3. And the screw holes 6 are regulated to be positioned at a predetermined measure in relation to a metal member 7 fixed extendingly along the axial direction on the knife cylinder 3. At both end portions of the knife cylinder 3, a right and left pair of fixing rings 8a, 8b are fitted-in slidably in the axial direction. At mutually opposing inner end faces of the fixing rings 8a, 8b, as shown in Fig. 1(C), corner cut-off portions with an up-grade to the center of the cylinder are formed all around the circumference and the fixing rings 8a, 8b can be fixed to the knife cylinder 3 via bolts 11 by making use of bolt holes drilled at predetermined places of the outer circumferential face of the knife cylinder 3.

[0027] In such structure, at the front end portion and the right and left end portions of the cutter fitting plate 4 fixed with a cutting knife 5, inclined faces with a down-grade are formed with such a same grade as to perfectly fit each of the up-grade inclined faces of a metal member 7 of a square timber shape and of the fixing rings 8a, 8b. Numeral 10 designates a metal element provided for decreasing a wearing and damage each of said inclined faces.

[0028] Fixing of the cutter fitting plate 4 is made first in a way that, as shown in Fig. 1(A), the front end of the cutter fitting plate 4 is inserted in (or hit to) the inclined face portion (or space) of the metal member 7 fixed on the knife cylinder 3 for positioning in the circumferential direction and then, as shown in Fig. 2, the cutter fitting plate 4 is fixed to the knife cylinder 3 via flat head bolts 9 one by one to the direction of the rear end side.

[0029] Next, the fixing rings 8a, 8b on the right and left end sides are moved respectively to the central direction so that they fit-in the right and left ends of the cutter fitting plate 4 and press the cutter fitting plate 4 via said inclined faces. In this state, the fixing rings 8a, 8b are fixed to the knife cylinder 3 by a small number of bolts 11.

[0030] In the knife cylinder 3 of this preferred embodiment as mentioned above, via the metal member 7 provided permanently at a fixed place and the fixing rings 8a, 8b provided at the right and left end portions detachably by a few bolts 11, the three faces of the front end and the right and left ends of the cutter fitting plate 4 are pressed and held securely and are prevented from floating.

[0031] Therefore, the number of the flat head bolts 9 used for fixing of the cutter fitting plate 4 is decreased so that they are used only partly at the central portion and the rear end portion of the cutter fitting plate 4, thereby a working time for a replacement of the cutter fitting plates 4 accompanying with a change of orders can be shortened greatly.

[0032] Incidentally, as for a fixing method (or means) etc. of the fixing rings 8a, 8b to press and support the right and left ends of the cutter fitting plate 4, there are considered various structures other than that exemplified. The present invention is not to be limited to the preferred embodiment as described above but may be added with various changes and modifications without departing from the spirit and scope of the invention.

[0033] In a knife cylinder in the prior art, a positioning of a front end of a cutter fitting plate is made by a metal member extending in the axial direction and a fixing thereof to the knife cylinder is made by a large number of bolts provided vertically and horizontally.

[0034] While in this preferred embodiment, a positioning and fixing of the front end of the cutter fitting plate 4 is made by the metal member 7 extending in the axial direction with a corner cut-off portion having an inclined face and a positioning and fixing thereof in the right and left direction can be made easily, securely and quickly by a right and left pair of annular metal members or fixing rings 8a, 8b, hence the fixing of the cutter fitting plate 4 to the knife cylinder 3 by way of bolting becomes possible by use of a small number of bolts.

[0035] Further, if a positioning of the cutter fitting plate 4 is so made, in addition to the metal member 7 extending in the axial direction, that a position of either one of the fixing rings 8a, 8b at the right and left ends is set previously and, by use of said metal member 7 and said one of the fixing rings 8a, 8b of which position is set previously, the cutter fitting plate 4 is positioned, and then the cutter fitting plate 4 is finally pressed by the other of the fixing rings 8a, 8b, a work of such positioning and a work of fixing of the cutter fitting plate 4 can be done further easily and quickly.

[0036] Therefore, even only with the front end positioning means of the cutter fitting plate 4 and the fixing means thereof to the knife cylinder 3 by use of the inclined face according to this preferred embodiment, in comparison with the conventional knife cylinder 3, shortening of a non-operation time of machines in case of a replacement of the cutter fitting plates 4 by a change of orders, increase of an operation time and enhancement of a productivity become possible to a large extent.

[0037] Further, even only with the right and left end positioning means of the cutter fitting plate 4 by use of annular rings 8a, 8b and the fixing means thereof to the knife cylinder 3 by use of the inclined faces, in comparison with the conventional knife cylinder 3, a sizable rationalization becomes possible, as seen in the preferred embodiment.

[0038] According to the present invention, as a positioning and fixing work of a front end of a cutter fitting plate fixed with a cutting knife and a positioning and fixing work of right and left ends of the cutter fitting plate, respectively, can be done easily, quickly and securely, the number of bolts as heretofore used for fixing the cutter fitting plate can be decreased greatly.

[0039] Thus, saving of a manpower can be realized. Further, a working time required for a replacement of cutting knives (or cutter fitting plates) accompanying with a change of orders can be shortened, and as such change of orders takes place frequently day by day, an operation rate of machines or a productivity can be enhanced greatly.

[0040] Especially, according to the Claim 1 of the present invention, as a cutter fitting plate is fixed only in engagement with metal members tri-directionally at its front end and both right and left ends and can be held on a cylindrical face securely and stably by a simple work not relying upon a bolting method etc., efficiency of a fixing and replacing work of the cutter fitting plates is greatly enhanced.

[0041] According to the Claim 2 of the present invention, as the cutter fitting plate and the metal members are formed with upward inclined faces and downward inclined faces, respectively, at their end portions and such inclined faces are lapped each other so that the cutter fitting plate is pressed by the metal members, mutual friction contact faces become larger and with an effect of wedge as well, a fixing of the cutter fitting plate can be done more securely and stably.

[0042] According to the Claim 3 of the present invention, as the right and left pair of circumferential directional metal members are formed as annular metal members to be fitted-in around the cylindrical face, these annular metal members are well fitted to the cylindrical face so as to be properly positioned, thus said fixing of the cutter fitting plate can be done furthermore securely.

[0043] According to the Claim 4 of the present invention, as one of the right and left pair of annular metal members is previously fitted-in fixedly around the cylindrical face and the other is detachably moved and adjusted of its position, positioning etc. of the cutter fitting plate becomes simple and facilitated, thus efficiency of a fitting and replacing work of the cutter fitting plates is further enhanced.

[0044] Further, according to the Claim 5 of the present invention, as the cutter fitting plate and each of the metal members are protected by metal elements provided inbetween, a wearing and damage of the contacting faces of the cutter fitting plate and each of the metal members is decreased, a life of machines is elongated and an accurate fixing of the cutter fitting plate can be maintained in a stable state for a long time.

Claims

1. A knife cylinder of a rotary die cutter in which a knife cylinder (3) is provided on its cylindrical face with a cutter fitting plate (4) of a bent rectangular plate shape having an arcuate cross section bent along said cylindrical face, characterized in that a metal member (7) is provided on said cylindrical face extendingly in the axial direction of said knife cylinder (3) in engagement with a front end of said cutter fitting plate (4) and a right and left pair of circumferential directional metal members (8a, 8b) are provided on said cylindrical face extendingly in the circumferential direction in engagement with the right and left ends of said cutter fitting plate (4), thereby said cutter fitting plate (4) is fixed on said cylindrical face tri-directionally in engagement with each of said metal members (7, 8a, 8b).

2. A knife cylinder of a rotary die cutter as claimed in Claim 1, characterized in that an upwardly inclined face is formed at each engaging end portion of said cutter fitting plate (4), a downwardly inclined face is formed at each engaging end portion of said metal members (7, 8a, 8b) and each downwardly inclined face of said metal members (7, 8a, 8b) presses each engaging upwardly inclined face of said cutter fitting plate (4), thereby said cutter fitting plate (4) is fixed on said cylindrical face.

3. A knife cylinder of a rotary die cutter as claimed in Claim 1 or 2, characterized in that said pair of circumferential directional metal members (8a, 8b) are formed as annular metal members to be fitted-in around said cylindrical face of the knife cylinder (3).

4. A knife cylinder of a rotary die cutter as claimed in Claim 3, characterized in that one of said pair of annular metal members (8a, 8b) is fitted-in fixedly around said cylinder face and the other is fitted-in detachably around said cylinder face.

5. A knife cylinder of a rotary die cutter as claimed in any one of Claims 1 to 4, characterized in that an engagement of said cutter fitting plate (4) and each of said metal members (7, 8a, 8b) is made via a metal element (10) inbetween.

Drawing