GB2342609A

GB2342609A - Method and apparatus for cutting sheet material

Info

Publication number: GB2342609A
Application number: GB9822306A
Authority: GB
Inventors: Anthony Paul Seymour
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-10-13
Filing date: 1998-10-13
Publication date: 2000-04-19
Also published as: GB9822306D0

Abstract

Continuous sheet material may need to be cut into smaller lengths before further processing. Cutting apparatus using knives and saw blades is bulky and has a high maintenance requirement. Herein, a duct section (1) forming part of an air conveyor receives continuous sheet material and delivers it to a cutting region (8). A laser beam generator (5, 7, 9 and 10) is operable to reciprocate a laser beam 6 transverse to the direction of movement of the sheet material in the cutting region (8). This cuts the sheet material in lengths which are then drawn off through the conveyor system.

Description

METHOD AND APPARATS FOR CUTTING SHEET MATERIAL This invention relates to the cutting of sheet material, more particularly but not exclusively continuous flexible sheet material, for example newsprint or other paper products.

Many production machines produce a continuous sheet of material which may need to be cut into smaller lengths for further processing. Existing machines use mechanical knives or blades to achieve this. Such machines are heavy and bulky which limits the positioning of the machine in the workplace, have many moving parts which need to be constant monitored and maintained, have wearable knives which need to be monitored and sharpened when necessary, and have a large power consumption which is costly to the end user, in cases where the product is very thin, the fine tolerances between the knives need to be maintained which amplifies the problems above.

The object of this invention is to provide a cutting device which has no mechanical knives, is lightweight, and does not require closer tolerances when cutting fine sheets.

According to one aspect of the invention, there is provided apparatus for cutting sheet matufial, the apparatus comprising an enclosure having an inlet for receiving said material into said enclosure and an exit for material conveyed through the enclosure to leave the enclosure, the apparatus further comprising laser beam forming means for directing a laser beam onto the sheet material and cutting it whilst it is conveyed through the enclosure.

Advantageously, the laser beam forming means is operable for directing a laser beam onto the sheet material so as to cut the sheet material transverse to the direction in which it is conveyed through the enclosure, for example by producing a laser beam which moves back and forth repetitively in the transverse direction. To achieve this, the laser beam forming means may include deflector means for receiving the laser beam, and drive means coupled to the deflector means for deflecting the beam so it moves back and forth as described above.

The deflector means could comprise a mirror and the drive means an electrical motor coupled to the mirror for turning the mirror.

In an embodiment to be described, the enclosure comprises a duct section for forming part of air conveyor means which conveys the sheet material through the duct section.

Preferably, the cross-sectional areas of the duct section upstream of the position where said material is cut is greater than at the cutting position, whereby air flowing through the duct section speeds up as it travels towards and through the cutting position.

The air conveyor system with cutting apparatus as just described may comprise a receiving station formed by or at least in proximity to said inlet of the cutting apparatus, and also in proximity to sheet material production machinery, the receiving station being operable to receive said continuous sheet material from the production machinery and the cutting apparatus being operable for cutting the material while the air conveyor system is operable for transporting the cut material.

According to the second aspect of the invention, there is provided a method of cutting sheet material, the method comprising conveying the material through an enclosure which has an inlet for receiving the material and an exit for the cut material to leave the enclosure, and directing a laser beam onto the sheet material so as to cut it whilst it is conveyed through the enclosure.

For a better understanding of the invention, an embodiment thereof will now be described by way of example with reference to accompanying drawings, in which: Figure 1 is a section on line A-A in Figure 2, and; Figure 2 is an end view of sheet material cutting apparatus.

As shown in Figure 1, the cutter comprises a tapered duct section 1 which opens out to a rectangular box section 2. A housing 3 is mounted to the top of the box section 2. Cut into the box section 2 and the housing 3 is a window 4. A suitable laser beam generator 5 is mounted in the housing 3. A laser beam 6 is directed from the laser beam generator 5 onto a small mirror 7 and is then reflected to the cutting region 8.

As can be seen in Figure 1, a small servo motor 9 has its shaft 10 attached to the centre of the mirror 7. The motor 9 is caused to turn repetitively between two variable limit positions and this causes the mirror 7 to rotate also. The laser beam 6 which impinges on the mirror 7 is thus made to sweep between the two positions 11 and 12 within the cutting area 8.

The duct section 1 has an inlet 13 and an exit 14. Attached to the duct 2 on both sides are ducts forming part of a conventional air conveying system (not shown) which causes air to flow from 13 to 14. Continuous sheet material (not shown) is conveyed in the duct with the air flow and passes from 13 to 14. The laser beam 6 impinges on the material at the cutting point 8 and cuts the material perpendicular to the flow of the material. The cut material is then drawn by the air flow from the cutting point 8 to the next process via duct exit 14.

Additionally, as can be seen in Figure 1, the duct section 1 tapers so its crosssection area at inlet 13 is larger than in the portion of the duct section between cutting area 8 and exit 14. This causes the air entering the duct at inlet 13 to speed up as it travels towards and into the cutting region 8. This causes the material to try to speed up also and hence improves the cutting action by ensuring that the material is drawn tight through the cutting area 8.

The constant airflow in the duct will serve to dissipate any build up of heat in the duct section 1 and the remaining parts of the conveyor and processing equipment.

Advantageously, control electronics (not shown) may vary the speed of rotation of the motor 9 and thus the speed of rotation of the mirror 7. Since the continuous sheet material is travelling along the duct 13 and 14 at a constant velocity, the user is therefore able to vary the length of the cut pieces of material.

The aforementioned air conveyor system (not shown) with the cutting apparatus as described above could comprise a receiving station formed by or at least in proximity to the inlet 13 of the cutting apparatus, and also in proximity to sheet material production or processing machinery (not shown). The receiving station is then able to receive continuous sheet material direct from the processing production machinery, the cutting apparatus being operable for cutting the material and the air conveyor system being operable for transporting the cut material to the next process and/or to a collection station.

The material could be waste newsprint received from a printing machine during the set-up phase of operating the machine. Instead any other form of paper waste could be presented to the cutting apparatus.

Claims

CLAIMS I. Apparatus for cutting sheet material, the apparatus comprising an enclosure having an inlet for receiving said material into said enclosure and an exit for material conveyed through the enclosure to leave the enclosure, the apparatus further comprising laser beam forming means for directing a laser beam onto the sheet material and cutting it whilst it is conveyed through the enclosure.
2. Apparatus according to any preceding claim, wherein the laser beam forming means is operable for directing a laser beam onto the sheet material so as to cut the sheet material transverse to the direction in which it is conveyed through the enclosure.
3. Apparatus according to Claim 2, wherein the laser beam forming means produces a laser beam which moves back and forth repetitively transverse to the direction of movement of the material.
4. Apparatus according to Claim 3, wherein the laser beam forming means includes deflector means for receiving the laser beam, and drive means coupled to the deflector means for deflecting the beam so it moves back and forth as aforesaid.
5. Apparatus according to Claim 4, wherein the deflector means comprises a mirror and the drive means includes an electrical motor coupled to the mirror for turning the mirror.
6. Apparatus according to any preceding claim, wherein the enclosure comprises a duct section for forming part of air conveyor means which conveys the sheet material through the duct section.
7. Apparatus according to Claim 6, wherein the cross-sectional area of the duct section upstream of the position where said material is cut is greater than at the cutting position, whereby air flowing through the duct section speeds up as it travels towards the cutting position.
8. An air conveyor system comprising cutting apparatus according to Claim 6 or 7 and a receiving station formed by or at least in proximity to said inlet of the cutting apparatus and also in proximity to sheet material production machinery for the receiving station to receive continuous sheet material from the production machinery, the cutting apparatus being operable for cutting the material and the air conveyor system being operable for transporting the cut material.
9. A method of cutting sheet material, the method comprising conveying the material through an enclosure which has an inlet for receiving the material and an exit for the cut material to leave the enclosure, and directing a laser beam onto the sheet material so as to cut it whilst it is conveyed through the enclosure.
10. Apparatus and method for cutting sheet material substantially as hereinbefore described with reference to the accompanying drawings.