WO2012057683A1

WO2012057683A1 - Method of cutting a block of material comprising stacked corrugated sheets

Info

Publication number: WO2012057683A1
Application number: PCT/SE2011/051269
Authority: WO
Inventors: Kurt Aldén
Original assignee: Design Force Ab
Priority date: 2010-10-28
Filing date: 2011-10-26
Publication date: 2012-05-03
Also published as: SE535555C2; SE1051131A1

Abstract

The invention relates to a method of cutting a block of material (1) comprising stacked corrugated sheets (2) forming a layered structure comprising channels (3). According to the invention, the block of material is positioned in a cutting device (6) comprising a reciprocating cutting blade (7) comprising a cutting edge (10) being arranged to reciprocate along a first path (11) during the reciprocating motion of the cutting blade, where after the block of material is moved along a second path (12) against the reciprocating cutting blade such that the cutting edge produces a cut surface in the block of material.

Description

Method of cutting a block of material comprising stacked corrugated sheets

[0001] The present invention relates to a method of cutting a block of material comprising stacked corrugated sheets forming a layered structure comprising channels.

[0002] In particular, the invention relates to such a method wherein the block of material is formed by stacked corrugated paper or cardboard sheets.

[0003] EP 1 714 776 A1 discloses a board or a panel comprising a core. The core is made from a block of material formed by stacking a plurality of corrugated sheets, preferably made of paper or cardboard. The corrugated sheets form a layered structure comprising flutes or channels. The corrugated sheets may be interleaved with substantially flat sheets, which are also preferably made of paper or cardboard. In order to form boards or panels from the block of material, the block is cut to slices, preferably such that the longitudinal axis of the channels intersect the cut surfaces at an angle of less than 90 degrees, where after facing sheets are attached to the cut surfaces.

[0004] This technique of manufacturing has enable the production of very thin boards and panels.

[0005] The cutting is typically performed using a band saw, a circular saw or any other cutting technique utilizing a saw blade. For example,

US 2006/0286354 discloses cutting a corrugated panel using rotating blades which are kerfed and serrated. However, a saw blade operates according to the principle of machining by detachment of cuttings or chippings and produces a relatively wide saw cut. Consequently, a cutting technique utilizing a saw blade produces a considerable amount of cuttings and dust. Also, such a cutting technique will give a low yield due to the large amount of spillage, especially when thin slices are cut from the block of material. [0006] The object of the invention is to attend to these drawbacks and produce a new method of cutting a block of stacked corrugated sheets, whereby thin cores of the above-described type can be produced efficiently.

[0007] The method according to the invention comprises the steps of:

- positioning the block of material (1 ) in a cutting device (6) comprising a reciprocating cutting blade (7) comprising a cutting edge (10) being arranged to reciprocate along a first path (1 1 ) during the reciprocating motion of the cutting blade (7), and

- moving the block of material (1 ) along a second path (12) against the reciprocating cutting blade (7) such that the cutting edge (10) produces a cut surface in the block of material (1 ).

[0008] The method according to the invention produces extremely even and clear cut surfaces also when very thin slices are cut from the block of material. Furthermore, since the cut surfaces are extremely even and flat, they are very well adapted to receive the above described facing sheets. Also, when the block of material is cut using the method according to the invention, very little wastages is produced, which is beneficial from a yield point of view as well as from an environmental point of view.

[0009] In the following the invention will be described in more detail with

reference to the appended drawing.

[0010] Fig. 1 schematically discloses a cutting device and a block of material to be cut using the method according to the invention.

[001 1] Fig. 1 discloses a block of material 1 comprising a plurality of stacked

corrugated paper sheets 2. The corrugated sheets 2 form a layered structure comprising flutes or channels 3 arranged in generally parallel layers 4. In the disclosed embodiment the corrugated sheets 2 are uniformly arranged so that the axes 5 of the channels 3 are substantially straight and mutually parallel throughout the whole block 1. However, it is understood that the channels 3 within a layer 4 as well as between different layers 4 may be non-parallel and/or have a varying width.

[0012] Fig. 1 also discloses a cutting device 6 comprising a continuous and

generally linear cutting blade 7 extending between a first blade end 8 and a second blade end 9. The cutting blade 7 is arranged to move in an oscillating or reciprocating motion between a first end position and a second end position, at which end positions the direction of motion of the cutting blade 7 is reversed. The cutting blade 7 comprises a cutting edge 10 which reciprocates along a first path 1 1 during the reciprocating motion of the cutting blade 7. Preferably, the first path 1 1 is generally linear.

[0013] The method of cutting the block 1 according to the invention involves

moving the block 1 along a second path 12 against the reciprocating cutting blade 7 such that the cutting edge 10 produces a cut surface in the block 1. Consequently, the first path 1 1 and the second path 12 define a cutting plane 13 in which the block 1 is cut. Preferably, the second path 12 is also generally linear and preferably the second path 12 is generally transversal to the first path 1 1. In order to achieve the preferred cut surface, i.e. a cut surface which the longitudinal axis 5 of the channels 3 intersect at an angle of less than 90 degrees, it is understood that the block 1 must be orientated prior to being brought into contact with the cutting blade 7 such that the longitudinal axis 5 of the channels 3 also intersect the cutting plane 13 at an angle of less than 90 degrees.

[0014] However, it is understood that the block 1 alternatively may be orientated such that the longitudinal axis 5 of the channels 3 intersect the cutting plane 13 at an angle of 90 degrees. Also, it is understood that the block 1 alternatively may be orientated such that the longitudinal axis 5 of the channels 3 are parallel to the cutting plane 13.

[0015] It is understood that the block 1 can be brought against the cutting blade 7 in a number of ways. Preferably, however, the cutting device 6 comprises a carriage or trolley 14 being arranged to travel back and forth under the cutting blade 7 along a path parallel to the second path 12. The carriage 14 comprises a table 15 and wheels 16 which are arranged to run along rails 17 to enable the back and forth movement of the carriage 14. The table 15 comprises a table surface 18 which is generally parallel to cutting plane, onto which surface 18 the block 1 is placed prior to being cut.

Preferably, the table 15 comprises means for fixedly fastening the block 1 to the table 15 in the preferred cutting orientation. Preferably, the carriage 14 also comprises means for adjusting the elevation of the table 15 whereby the slice thickness can be adjusted. Alternatively, the cutting device 6 may comprise means by which the height of the cutting blade 7 can be adjusted.

[0016] A cutting operation according to a preferred embodiment of the method of the invention will now be described in more detail. The carriage 14 is positioned in front of the cutting blade 7 in a starting position. Thereafter, the block 1 is placed onto the table surface 18 and orientated such that the axis 5 of the channels 3 intersect the table surface 18 at an angle of less than 90 degrees. Thereafter, the block 1 is fixedly attached to the table surface 18 and, if necessary, the relative height between the cutting blade 7 and the table surface 18 is adjusted such that the cutting plane 13 defines the thickness of the slice to be cut. Thereafter, the reciprocating motion of the cutting blade 7 is initiated and the carriage 14 is brought to travel towards and under the reciprocating cutting blade 7 such that the cutting edge 10 is brought into contact with the block 1 and cuts a slice from the block 1. The slice thus separated from the block 1 is collected and the carriage 14 and the remaining block 1 is brought back to the starting position. Thereafter the table is elevated or, alternatively, the cutting blade 7 is lowered such that the cutting plane 13 defines a new slice to be cut and the forward motion of the carriage 14 is once again initiated. This sequence is repeated until the whole block 1 has been cut into slices, where after a new block is positioned onto the table 15 and the cutting operation is repeated.

[0017] As is well known in the art, a block comprising stacked corrugated paper or cardboard sheets is very abrasive and will quickly blunt the cutting edge 10. Therefore, the cutting device 6 preferably comprises means for continuous sharpening of the edge 10. A preferred embodiment of such a sharpening means (not disclosed) comprises one or a plurality of sharpening units or stations straddling the path 1 1 of the cutting edgel 0. According to a preferred embodiment, a first sharpening unit 19 is positioned straddling the path 1 1 at one side of the path 1 1 and a second sharpening unit 20 is positioned straddling the path 1 1 at the other side of the path 1 1 at a distance from the first sharpening unit 19, enabling the block 1 to pass between the sharpening units 19, 20 during its forward motion. The sharpening units 19, 20 may comprise a pressure loaded sharpening stone or any other sharpening device which is known within the art.

[0018] Alternatively, the sharpening means may comprise only one sharpening unit or station straddling the path 1 1 of the cutting edgel 0 outside the traveling path of the block 1.

[0019] The stroke length and the frequency of the reciprocating cutting blade 7, the characteristics of the cutting edge 10 and the feeding speed of the block 1 , i.e. the speed at which the block 1 is brought to travel against the cutting blade 7, are adopted to the characteristics of the block 1 to be cut. Such characteristics are for example the dimensions of the block, e.g. the width of the block, as well as the physical characteristics of the block, e.g. the type of material, the density and the inter-layer distance of the block. Preferably, however, the cutting device is adopted to cut a slice from the block using as few strokes of the cutting blade as possible. Consequently, a relatively wide and dense block may require a relatively long cutting blade and a relatively long stroke length of the cutting blade.

[0020] Generally, however, the length of the cutting blade and also the stroke length of the cutting blade 7 should be at least as long as the width of the block to be cut. The cutting edge 10 may be smooth but preferably it is serrated. [0021] According to one embodiment of the invention, the length of the cutting blade 7 is approximately the same as or slightly longer than the width of the block 1 to be cut, and the stroke length of the reciprocation motion of the cutting blade 7 is w +2-l, where w \s the width of the block 1 to be cut and / is the length of the cutting blade 7. In this embodiment the end positions of the reciprocating cutting blade 7, i.e. the positions at which the direction of motion of the reciprocating cutting blade 7 is reversed, is outside the traveling path of the block 1. In other words, referring to Fig. 1 , at the first end position the second blade end 9 is outside the first side 21 of the block 1 and at the other end position the first blade end 8 is outside the second side 22 of the block 1. If two sharpening units 19, 20 are arranged as disclosed in Fig. 1 , the whole length of the cutting edge 10 will be sharpened four times during a back and forth cycle; one time when the blade 7 leaves the first end position, one time when the blade 7 enters the second end position, one time when the blade 7 leaves the second end position and one time when the blade 7 enters the first end position. Consequently, the whole edge 10 is sharpened twice during each traverse of the cutting blade 7, once by the first sharpening unit 19 and once by the second sharpening unit 20.

[0022] According to another embodiment of the invention, the length of the cutting blade 7 is approximately twice the width of or slightly longer than twice the width of the block 1 to be cut, and the stroke length of the reciprocation motion of the cutting blade 7 is w +/, where w^'vs, the width of the block 1 to be cut and /is the length of the cutting blade 7. In this embodiment the second blade end 9 is in line with the second side 22 of the block 1 when the blade 7 is at the first end position, and the first blade end 8 is in line with the first side 21 of the block 1 when the blade 7 is at the other end position. If two sharpening units 19, 20 are arranged as disclosed in Fig. 1 , the whole length of the cutting edge 10 will be sharpened twice during a back and forth cycle. When the blade 7 travels in one direction, a first half of the edge 10 will be sharpened by the first sharpening unit 19 and simultaneously the second half of the edge 10 will be sharpened by the second sharpening unit 20. When the direction of motion of the blade 7 is reversed, this sharpening action is repeated. Consequently, the whole edge 10 is sharpened once during each traverse of the cutting blade 7. In the foregoing the invention has been disclosed in relation to specific embodiments. It is, however, understood that other embodiments, versions and variants may be encompassed by the invention.

Reference Numerals block of material

corrugated paper sheet

channel

layer

axis

cutting device

cutting blade

first blade end

second blade end

cutting edge

first path, path of the cutting edge

second path, path of the carriage

cutting plane

carriage, trolley

table

wheel

rail

table surface

first sharpening unit or station

second sharpening unit or station

first side of block 1

second side of block 1

Claims

1. A method of cutting a block of material (1 ) comprising stacked corrugated sheets (2) forming a layered structure comprising channels (3), characterized by the steps of:

- positioning the block of material (1) in a cutting device (6) comprising a reciprocating cutting blade (7) comprising a cutting edge (10) being arranged to reciprocate along a first path (1 1) during the reciprocating motion of the cutting blade (7), and

2. The method as claimed in claim 1 , characterized in that the first path (1 1 ) is generally linear.

3. The method as claimed in any one of the preceding claims, characterized in that the second path (12) is generally linear.

4. The method as claimed in any one of the preceding claims, characterized in that the second path (12) is generally transversal to said first path (1 1 ).

5. The method as claimed in any one of the preceding claims, characterized in that the cutting edge (10) is sharpened during the reciprocating motion of the cutting blade (7).

6. The method as claimed claim 5, characterized in that the cutting edge (10) is sharpened by a sharpening means (19, 20) straddling said first path (1 1 ).

7. The method as claimed claim 6, characterized in that the sharpening means comprises a first sharpening unit (19) being positioned straddling the first path (1 1 ) and a second sharpening unit (20) being positioned straddling the first path (1 1 ) at a distance from the first sharpening unit (19) enabling the block of material (1 ) to pass between the sharpening units (19, 20) during its motion along the second path (12).

8. The method as claimed in any one of the preceding claims, characterized in that the length of the cutting blade (7) is at least as long as the width of the block of material (1 ) to be cut.

9. The method as claimed claim 8, characterized in that the length of the cutting blade (7) is approximately the same as or slightly longer than the width of the block of material (1 ) to be cut.

10. The method as claimed claim 8, characterized in that the length of the cutting blade (7) is approximately twice the width of or slightly longer than twice the width of the block of material (1 ) to be cut.

1 1. The method as claimed in any one of the preceding claims, characterized in that the longitudinal axis (5) of the channels (3) intersect the cut surface at an angle of less than 90 degrees