DIE CUTTER BLANKET FOR COUNTER-DIE OF ROTARY DIE CUTTING MACHINE, AND METHOD FOR MANUFACTURING THE SAME

Abstract

Die cutter blanket for counter-die of rotary die cutting machine, which has a cover (3) that wraps the counter-die (1) forming a cylindrical sleeve around said counter-die (1). The cover (3) has a key (4) insertable into a slot (5) of the counter-die (1) for the fixing thereof around the counter-die (1). Additionally, the cutter blanket (2) comprises a bar (6) inserted inside the key (3) axially along its entire length, in such a way that the dimensions of the section of the bar (5) fit the geometry of the slot (5), and the bar (6) is peripherally coated by the same material of the cover (3). The bar (6) has higher hardness than the cover (3).

Claims

1. Die cutter blanket for counter-die of rotary die cutting machine, comprising a cover that wraps the counter-die forming a cylindrical sleeve around said counter-die, said cover comprising in turn a key insertable into a slot of the counter-die for the fixing thereof around the counter-die, at least a stabilizing inner bar inserted inside the key axially along its entire length, the dimensions of the section of the inner bar fitting the geometry of the slot and being peripherally coated by the cover, wherein both the inner bar and the key are interrupted, and thereby divided in several parts, as well as the inner bar has higher hardness than the cover, for increasing dimensional stability of the cover.

2. Die cutter blanket for counter-die of rotary ting machine, according to claim 1, die cut wherein both the key and the inner bar are interrupted and divided in several parts along a longitudinal direction of the key and the inner bar.

3. Die cutter blanket for counter-die of rotary die cutting machine, according to claim 1, wherein the inner bar has a hardness up above 50 ShD.

4. Die cutter blanket for counter-die of rotary die cutting machine, according to claim 1, wherein the cover comprises at each end a plurality of fingers engageable with the fingers of the other end, which provides a jig-saw joint of both ends of the die cutter blanket, forming the cylindrical sleeve around the counter-die.

5. Die cutter blanket for counter-die of rotary die cutting machine, according to claim 4, wherein the fingers interrupt and divide the key and the insert into several parts.

6. Die cutter blanket for counter-die rotary die cutting machine, according to claim 4, wherein the fingers of the ends of the cover comprise: two lateral sides and a front part.

7. Die cutter blanket for counter-die rotary die cutting machine, according to claim 4, wherein the front part of the fingers is arrowhead-shaped comprising two straight portions joined at a vertex, forming an angle (b) comprised between 120? and 170?.

8. Die cutter blanket for counter-die of rotary die cutting machine, according to claim 6, wherein the lateral sides form an angle (a) comprised between 70? and 85? with the longitudinal axis of the cover.

9. Die cutter blanket for counter-die of rotary die cutting machine, according to claim 1, wherein the cover is made of polyurethane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Next, in order to facilitate the comprehension of the invention, in an illustrative rather than limitative manner an embodiment of the invention with reference to a series of figures shall be made below.

[0031] FIG. 1 shows a schematic section view of a blanket known in the prior art.

[0032] FIG. 2 is a schematic front view of one end of a blanket known in the prior art showing the fingers of the joining system.

[0033] FIG. 3 shows a schematic section view of another blanket known in the prior art, with a key made of a material harder than the counter-die surface.

[0034] FIG. 4 shows an overall schematic view of the ends of the blanket of FIG. 3.

[0035] FIGS. 5a, 5b and 5c show schematically different conventional joining systems known in the prior art for the joint of the ends of the blankets to form the cylindrical sleeve wrapping the counter-die.

[0036] FIG. 6 shows a schematic section view of a blanket according the present invention.

[0037] FIGS. 7a and 7b show an overall schematic view of the ends of the blanket of FIG. 6, FIG. 7a showing the ends of the blanket in an open finger position, and FIG. 7b showing the ends of the blanket in a closed finger position.

[0038] FIG. 8 shows a inner bar inserted in the slot of a mould, before vulcanized with soft material, according to the present invention.

[0039] FIG. 9 shows a schematic front view of one end of a blanket with the typical position of the inner bar inside the fingers with straight section.

[0040] FIG. 10 shows schematically a joining system for the joint of the ends of the blankets to form the cylindrical sleeve wrapping the counter-die, according a preferred embodiment of the present invention.

[0041] FIG. 11 shows in detail the fingers of the joining system of the embodiment of FIG. 10.

[0042] These figures refer to the following set of elements: [0043] 1. counter-die of the rotary die cutting machine [0044] 2. die cutter blanket [0045] 3. cover of the die cutter blanket [0046] 4. key of the cover of the die cutter blanket [0047] 5. slot of the counter-die [0048] 6. inner bar inserted inside the key of the die cutter blanket [0049] 7. ends of the die cutter blanket [0050] 8. fingers at both ends of the die cutter blanket [0051] 9. lateral sides of the fingers [0052] 10. front part of the fingers [0053] 11. straight two portions of the front part of the fingers [0054] 12. vertex of the front part of the fingers [0055] b. angle between the two straight portions of the front part of the finger [0056] a. angle of the lateral sides of the finger with the longitudinal axis of the cover

DETAILED DESCRIPTION OF THE INVENTION

[0057] The object of the present invention is a die cutter blanket for counter-die of rotary die cutting machine.

[0058] As shown in the figures, the die cutter blanket has a cover 3 that wraps the counter-die 1 forming a cylindrical sleeve around said counter-die 1. The cover is made of a soft material, preferably polyurethane.

[0059] The cover 3 comprises in turn a key 4 which is insertable into a slot 5 of the counter-die 1 for the fixing thereof around said counter-die 1.

[0060] The die cutter blanket comprises at least an inner bar 6 inserted inside the key 3 axially along its entire length, although according different embodiments of the invention, the inner bar 6 could be divided in several parts, or there could be more than one inner bar 6. As shown in FIGS. 6, 7a, 7b and 8, the dimensions of the section of the inner bar 6 fits the geometry of the slot 4, being the inner bar 6 peripherally coated by the cover 3.

[0061] The inner bar 6 has higher hardness than the cover 3, and particularly, the inner bar 6 has a hardness close to the counter die 1 on which it lies, and unlike prior art covers with metal key does not need external elements to fix the cover to the cylinder. So, an improvement on accuracy processing cardboard is achieved. According a preferred embodiment of the invention, the hardness of the inner bar 6 is up above 50 ShD, whereas that the hardness of the cover 3 is comprised between 85-95 ShA.

[0062] Preferably, for the most common key dimensions, a 0.5 mm thickness of coating material of lower hardness around the inner bar 6 is enough to ensure correct installation and ensure the functionality of the bar 6.

[0063] With accord to a particular embodiment of the invention, and regarding the joint of the ends 7 of the cover 3 to form the cylindrical sleeve around the counter-die 1, the cover 3 comprises at each end 7 thereof a plurality of fingers 8 engageable with the fingers 8 of the other end 7, which provides a jig-saw joint of both ends 7 of the die cutter blanket 2.

[0064] Particularly, and as it can be seen at FIGS. 10 and 11, the fingers 8 of the ends 7 of the cover have two lateral sides 9 and a front part 10, and according to a preferred embodiment, the front part 10 of the fingers 8 is arrowhead-shaped comprising two straight portions joined at a vertex 12, in such a way that they form an angle b comprised between 120? and 170?. These angles b are designed to avoid cutting, scoring or void cutting of axial direction blades, as usual in the cardboard processing. Values too big would reduce the desired effect, and values too small would greatly increase the finger 8 length and worsen the quality of the joint, since the fingers would not follow the curvature of the counter-die 1 (the longer the finger, the worse quality).

[0065] Preferably, the lateral sides 9 form an angle a comprised between 70? and 85? with the longitudinal axis of the cover 3, in order to adapt the geometry of the fingers 8 to the height thereof, which is defined in terms of width of the cylinder slot. This will ensure that collisions between fingers 8 are minimized, making easier the die cutter blanket 2 assembly and disassembly operations. Therefore, productivity will be increased by means of shortening cover assembly and disassembly time.

[0066] Once the invention has been clearly described, it is hereby noted that the particular embodiments described above can be the subject of detail modifications as long as they do not alter the fundamental principle and the essence of the invention.