The invention relates to a transport apparatus comprising an conveyor belt which is drivable by drive means, said conveyor belt comprising an active upper part for carrying along flat, thin material to be cut, for example by means of a laser with a galvanometer or with a nozzle, in a transport direction wherein said material extends substantially in a plane, said material to be cut being for example textile, non-woven, sandpaper, cardboard or plastic film material.

The conveyor belt can be driven during operation by generally usual and known drive means. The conveyor belt defines a substantially plane and flat active upper part for carrying said material, which is to be transported and cut by for example infrared laser radiation from a laser with a galvanometer (scanner) or with a nozzle during transport. Said material to be cut is transported in said transport direction by said conveyor belt. Cutting may for example take place under an angle of approximately 90° with respect to the longitudinal direction of said material to be cut, i.e. substantially perpendicular to the longitudinal direction of said material. Depending on for example the transport speed of the conveyor belt cutting may take place under angle varying between for example approximately 90° to for example approximately 120° with respect to the transport direction of said conveyor belt. Said conveyor belt is for example an endless conveyor belt. A disadvantage of the above described transport apparatus is that said laser radiation impinges upon the active upper part of the conveyor belt when it cuts through the material, which may melt or otherwise damage the conveyor belt, in particularly the active upper part thereof. It is an object of the invention to overcome the above described disadvantage. In particular it is an object of the invention to provide a transport apparatus of the type described in the preamble in which said active upper part of the conveyor belt is protected from being damaged by said laser radiation.

In order to achieve this objective a transport apparatus of the type described in the preamble is adjusted such that it comprises a means for displacing the active upper part of the conveyor belt in a direction away from said plane in a cutting area, and in that a protection means is arranged between said plane and the active upper part of the conveyor belt in said cutting area for protecting said active upper part. By displacing the active upper part of the conveyor belt away from said plane in which said material to be cut extends during use of the transport apparatus, and by arranging said protection means between the active upper part of the conveyor belt and said plane, the laser radiation used for cutting said material to be cut impinges on said protection means and not on said active upper part of the conveyor belt, such that damage thereof may be prevented or at least reduced.

In an embodiment of the transport apparatus according to the invention, said protection means has a substantially C-shaped or U-shaped cross-section, wherein said protection means is arranged such that the open part of the C-shaped or U-shaped cross-section is facing said plane. Such a shape of said protection means, comprising a bottom wall and two side walls forming said U or C, may effectively shield said active upper part of the conveyor belt from said laser radiation, because the shape of said protection means is more or less adapted to the shape of the displaced active upper part of the conveyor belt in said cutting area, as seen in a, in use, vertical cross section of the apparatus parallel to the transport direction. The protection means is thus more or less shaped as a gutter or a channel. In another embodiment of the transport apparatus according to the invention, said protection means comprises a material for absorbing or diverging laser radiation, for example sintered alumina, said material for absorbing or diverging laser radiation being arranged on a surface of said protection means that is facing said plane.

By absorbing or diverging said laser radiation it may be prevented that said laser radiation is reflected by said protection means and then damages said conveyor belt or said material to be cut. Said protection means may for example be made of such a material for absorbing or diverging laser radiation, or said protection means may have a layer of said material for absorbing or diverging laser radiation arranged on a base or support layer. Said optional base or support layer may for example be made of any suitable metal or plastic. Sintered alumina is a good choice for said material for absorbing or diverging laser radiation.

In yet another embodiment of the transport apparatus according to the invention, said means for displacing the active upper part of the conveyor belt is arranged such that said cutting area in which said active upper part is displaced extends substantially parallel to said plane under an angle with respect to the transport direction.

Because the material to be cut is transported during cutting, said cutting area in which said active upper part is displaced preferable extends under an angle with respect to the transport direction parallel to said plane in which the material to be cut is transported during use of the apparatus. By arranging said cutting area under said angle the width of the cutting area may be reduced, such that said active upper part is displaced over a relatively small length and may thus provide a larger support area for said material to be cut. The angle may for example depend on the transport speed of the conveyor belt and/or on the cutting speed of the laser, wherein the angle increases with increasing transport speed and/or wherein the angle decreases with increasing cutting speed. In this embodiment the protection means also extends under said angle.

For example, said angle may lie in the range of 90° - 150°, or in the range of 90° - 135°, or in the range of 90° - 120°, or in the range of 90° - 110°, or in the range of 100° - 120°. In particular, said angle may be chosen to be larger than 90°.

In even another embodiment of the transport apparatus according to the invention, said conveyor belt comprises a plurality of belt and/or strap and/or band shaped conveyor belts arranged at a certain mutual distance, each belt comprising a said active upper part, and wherein said apparatus comprises a plurality of said means for displacing said active upper parts of said belts in said direction away from said plane in said cutting area.

In such an embodiment of the transport apparatus each belt is displaced separately and independently from the other belts by means of each means for displacing the active upper parts of said belts. This increases the flexibility of said cutting area, because each belt may be displaced at a suitable location and/or over a suitable length.

Preferably, said means for displacing said active upper parts are movable substantially parallel to said transport direction by a moving means, for adjusting an angle of said cutting area with respect to the transport direction. As described above, it is preferred that said cutting area extends parallel to said plane under an angle with respect to the transport direction. By having said means for displacing said active upper parts movable by said moving means, the angle of said cutting area may easily be adjusted, for example in accordance with a transport speed of said conveyor belt. Said means for displacing said active upper parts are movable back and forth with respect to the transport direction. By having the angle of said cutting area adjustable, for example in accordance with said transport speed, the width of said cutting area may be decreased, such that the contact area of said belts for said material to be cut may be increased. In this embodiment the protection means is also movable, such that the position thereof is adapted to the position of the cutting area.

For example, said adjustable angle may lie in the range of 90°

- 150°, or in the range of 90° - 135°, or in the range of 90°

- 120°, or in the range of 90° - 110°, or in the range of 100°

- 120° .

As described above, because each belt is displaceable separately and independently from the other belts by means of each means for displacing the active upper parts of said belts, each belt may be displaced at a suitable location and/or over a suitable length that is different from the locations of the other belts and/or different from the length by which the other belts are displaced, thereby creating said described adjustable angle.

Practically said means for displacing said active upper parts are pivotally connected to said moving means, such that a rotational movement of the moving means is transmitted in a translational movement of said means for displacing said active upper parts . In such a practical arrangement all means for displacing said active upper parts are connected to one said moving means, such that all means for displacing said active upper parts are moved coherently. In such an arrangement, the total cutting area may easily be formed as a straight line or band, extending under said angle with respect to the transport direction.

In an embodiment of the transport apparatus according to the invention, said moving means comprises said protection means, which protection means is pivotally connected to said means for displacing said active upper parts.

In such an embodiment said protection means may be rotated, thereby providing a translational movement of said means for displacing said active upper parts.

Practically said apparatus comprises a motor for driving said moving means .

Said motor may be arranged for driving said moving means in response to a transport speed of said belts, such that the angle of said cutting area with respect to the transport direction is adjustable in accordance with said transport speed.

As described above, the angle of the cutting area is preferable chosen in accordance with the transport speed of the belts, wherein the angle is increased with increasing transport speed and vice versa. In an arrangement in which the motor is arranged for driving said moving means in response to said transport speed, the angle may be automatically adjusted in accordance with the transport speed.

Preferably said motor is arranged for driving said moving means during a cutting process, such that the moving means are able to move said means for displacing said active upper parts during said cutting process.

The transport speed of the conveyor belt may vary during a cutting process. As such it is preferred that said means for displacing said active upper parts may be moved during said cutting process, in accordance with said varying speed.

In a practical arrangement of said transport apparatus, said means for displacing said active upper part(s) comprises an assembly of three wheels for displacing said active upper part or a plurality of assemblies of three wheels for displacing said plurality of active upper parts, wherein the three wheels of the or each assembly are distanced from each other in the transport direction, and wherein a middle wheel is arranged at a larger distance from said plane.

In such an arrangement the or each belt is deflected by the or each assembly of three wheels, for displacing said belt(s) away from said plane. Optionally the or each arrangement may comprise more than three wheels, for example four wheels.

In yet another embodiment of the transport apparatus according to the invention, said apparatus comprises a suction device connected to said protection means, for sucking smoke or the like away from said cutting area.

For efficient cutting of thin materials with an IR laser these materials must lie flat and be properly fixed relative to the active upper part of the conveyor belt. The belt(s) may for this purpose be provided with a plurality of holes connected to a suction means such as a fan. The material for transporting is hereby suctioned fixedly to the active upper part of the conveyor belt (s) . The invention further relates to a cutting device, comprising a transport apparatus as described above, said transport apparatus comprising an conveyor belt which is drivable by drive means, said conveyor belt comprising an active upper part for carrying along flat, thin material to be cut, for example by means of a laser with a galvanometer or with a nozzle, in a transport direction wherein said material extends substantially in a plane, said material to be cut being for example textile, non-woven, sandpaper, cardboard or plastic film material, said transport apparatus comprises means for displacing the active upper part of the conveyor belt in a direction away from said plane in a cutting area, and in that a protection means is arranged between said plane and the active upper part of the conveyor belt in said cutting area for protecting said active upper part, and said cutting device comprising a cutting means for cutting said material to be cut.

Said cutting means may comprise a laser with a galvanometer (scanner) or with a nozzle. Such a laser with a galvanometer will be arranged above said conveyor belt and said material to be cut, wherein the pattern of said laser radiation is adjustable and/or controllable. Such a laser with a nozzle may for example be connected to said protection means, such that said laser is movable over the length of said protection means and is able to cut said material over the length of said cutting area.

The infrared laser radiation may have a wavelength in the range of 8 - 12 pm, more specifically in the range of 9 - 11 pm, even more specifically in the range of 9.2 - 10.6 pm.

In the accompanying figures:

Figure 1 shows a schematic vertical cross section of a transport apparatus according to the invention; Figures 2A and 2B show a schematic top view of the transport apparatus of figure 1 ;

Figure 3 is a perspective view of a part of a transport apparatus according to a second embodiment of the invention; and

Figure 4 is a cross section of an assembly of three wheels of the transport apparatus of figure 3.

Figure 1 shows a transport apparatus 1 comprising an endless conveyor belt 2 which is drivable by drive means (not shown) . An active upper part 3 of the conveyor belt 2 is arranged for transporting thin materials 4 such as textile, non-woven, sandpaper, cardboard, plastic film material, which material is to be cut by a cutting means (not shown) . Said cutting means may for example comprise a laser for irradiating infrared laser radiation. Said laser may be a well known laser with a galvanometer (scanner) or with a nozzle. Said material 4 to be cut is transported by said conveyor belt 2 in a transport direction 5 and extends in a more or less horizontal plane. Said conveyor belt 2 is perforated, which perforations 12 (see also figures 2A, 2B) connect to vacuum devices 6 arranged below said conveyor belt 2 for creating an underpressure, such that said material 4 is held more or less fixed against the active upper part 3 of the conveyor belt 2. In accordance with an aspect of the invention, said active upper part 3 is displaced away from said plane in which said material 4 extends during transportation in a cutting area 7. A means for displacing said active upper part 4 comprises an assembly of three wheels 8 - 10. The three wheels 8 - 10 are distanced from each other in the transport direction, wherein a middle wheel 9 is arranged at a larger distance from said plane. As such, the middle wheel 9 displaces said active upper part 4 away from said plane, which is downwards in figure 1. The two other wheels 8 and 10 define the location where the displacement of the active upper part 4 starts and ends, respectively, such that the size of the width of the cutting area 7 is defined by said two wheels 8 and 10. Thus, by adjusting the distance between the two wheels 8 and 10 the width of the cutting area 7 may be chosen. A gutter 11 is arranged between said plane and the active upper part 4 of the conveyor belt 2 in said cutting area 7 for protecting said active upper part 4. The gutter 11 has a cross-section that is substantially C-shaped or U-shaped, wherein the open part of the C-shaped or U-shaped cross-section is facing said plane. Said gutter 11 is preferably made of, or comprises a layer of, a material for absorbing or diverging laser radiation, for example sintered alumina. If said material for absorbing or diverging laser radiation is provided as a layer on another support or base layer, said material is arranged on a surface of said gutter 11 that is facing said plane. Said gutter 11 protects said active upper part 4 from being damaged in said cutting area 7.

Figures 2A and 2B show a top view of the transport apparatus 1. From this figure it is clear, that said conveyor belt 2 comprises a plurality of belt and/or strap and/or band shaped conveyor belts 2a - 2d, arranged at a certain mutual distance. Each belt 2a - 2d comprises an respective active upper part 5a - 5d. Said mutual distance may be suitably chosen, for example in accordance with the number of belts 2a - 2d and/or in accordance with a desired working width of the conveyor belt 2. Each belt 2a - 2d is displaceable by an assembly of three wheels 8 - 10, wherein the location of the wheels 8 and 10 below the belts 2a - 2d are denoted schematically by dotted lines. Figures 2A and 2B show that said assemblies of three wheels 8 - 10 for displacing said active upper parts 5a - 5d are movable back and forth parallel to said transport direction 5 by said gutter 11. The 11 gutter is pivotally connected to each assembly and is drivable by a motor 13. Said motor 13 comprises a linear actuator 15 that is pivotally connected to a first end zone of said gutter 11. The other end zone of said gutter 11 is pivotally connected to a fixed pivot point 14. The translational movement of the motor 13 is thereby transmitted in a rotational movement of said gutter 11, wherein the rotational movement of the gutter 11 is transmitted in a translational movement of each assembly. By moving the assemblies the location of the cutting area 7 in which the active upper parts 5a - 5d are displaced is moved, thereby varying the angle a of the cutting area 7 with respect to the transport direction 5. In figure 2a the angle a is 90°, which corresponds to a transport speed of the belts 2a - 2d of approximately 0 m/s . In figure 2b the angle a is approximately 120°, which corresponds to a maximum transport speed of the belts 2a - 2d. The maximum speed may be suitably chosen, for example in accordance with the speed of cutting and/or in accordance with the type of material 4 to be cut. The cutting area 7 may be adjusted under any desired angle between the minimum angle of 90° and the maximum angle of 120°. The cutting area 7 is thereby rotatable over a maximum angle β of 30°. It is noted that, if desired, other minimal and/or maximal angles a may be chosen and that the angles a and β are not limited to the values disclosed in this example embodiment. For example, said angle a may lie in the range of 90° - 150°, or in the range of 90° - 135°, or in the range of 90° - 120°, or in the range of 90° - 110°, or in the range of 100° - 120°.

It is further noted, that the transport speed is an important factor in defining the angle of cutting, wherein the angle a of the cutting area 7 is preferably adjusted to the angle of cutting. The assemblies are thus moved by the motor 13 in accordance with the required angle a of the cutting area 7. Moving may take place during a cutting process to compensate for a varying transport speed. By having the angle of the cutting area 7 being adjustable to the transport speed, the width of the cutting area 7, i.e. the length of the displacement area of the conveyor belt 2, may be relatively small. Otherwise, the width should be large enough to provide a suitable cutting area 7 for various transport speeds. By having a smaller width of the cutting area 7, the contact surface of the conveyor belt 2 for supporting the material 4 is relatively large.

It is further noted, that said cutting angle with respect to the transport direction 5 of the conveyor belt may preferably provide cutting of the material 4 under an angle of approximately 90° of the longitudinal direction of said material 4. In such a way, said material 4 is cut substantially perpendicular to its longitudinal direction for preferably every chosen transport speed of the conveyor belt 2. It is noted that, if desired, said material 4 may be cut under other angles than perpendicular to its longitudinal direction.

Figure 3 shows a perspective view of a transport apparatus 101 according to another embodiment of the invention. Figure 4 shows an assembly of the apparatus 101 in more detail. Similar elements will be denoted by similar numbers increased by 100. Only the differences with respect to the apparatus 1 of figures 1 and 2 will be described. For a further description of the apparatus 101 the reader is referred to the description of figures 1 and 2.

The apparatus 101 comprises a plurality of rails 16a - 16g, wherein to each rails 16a - 16g one block or assembly of three wheels 108 - 110 is mounted. The first assembly of three wheels 108 - 110 is fixedly mounted to the first rails 16a, such that the first assembly cannot be moved in the transport direction 105. The intermediate assemblies are moveably mounted to the intermediate rails 16b - 16f, such that the intermediate assemblies are moveable back and forth in the transport direction 105. The last assembly is moveably mounted to the last rails 16g and is drivable back and forth in the transport direction 105 by a motor (not shown) . The assemblies are coupled to each other by means of the gutter 111, which gutter 111 is pivotally connected to each assembly. By driving said last assembly back and forth in the transport direction 105, the gutter 111 is rotated back and forth over angle β, such that the intermediate assemblies are moved back and forth in the transport direction 105. The axis of rotation of the gutter 111 is denoted by numeral 17. The gutter 111 comprises a connecting element 18 for connecting the gutter 111 to a suction device (111) . By means of said suction device smoke and the like can be sucked away from said cutting area . Figure 4 shows one of the intermediate assemblies of figure 3 in more detail and in cross section. Said assembly comprises said three wheels 108 - 110 for displacing the active upper part 104 of the conveyor belt 102. The wheels 108 and 110 comprises teeth 19 for gripping onto said conveyor belt 102, such that by rotating said wheels 108 and 110 said conveyor belt 102 is moved in the transport direction. Said wheel 109 is a guiding wheel for displacing the upper part 104 away from said plane and comprises no teeth. The block or assembly of three wheels 108 - 110 is moveably mounted to said rails 16c by means of transport wheels 20, that are arranged in said rails 16c.

The invention is not limited to the embodiments shown but also extends to other variants within the scope of the appended claims .

For example, instead of a plurality of belts arranged at a certain mutual distance, said conveyor belt may comprise one broad belt.

Also for example, said means for displacing the active upper part of the belt (s) may comprise other means than the assembly of three wheels shown in the figures, or it may comprise an assembly with another number of wheels, for example four wheels.

Further for example, said means for displacing the active upper part of the belt(s) may be in a fixed location such that the angle of the cutting area is not adjustable. Said fixed angle may then be chosen in accordance with a range of transport speeds. This will increase the required width of the cutting area, but for certain applications such an increased width may be preferred over a more complex apparatus comprising movable means for displacing the active upper part of the conveyor belt.