Device for cross-cutting web materials

Abstract

 A device (1) for cross-cutting web materials is provided with a blade (10) carried by a roller (11) that rotates about an axis of rotation (R), a counter-blade (12) carried by a movable supporting member (13), and an actuator system (14) to bring the blade and the counter-blade so as to cooperate cyclically with one another; the actuator system (14) comprises a rotating shaft (35), driven by a motor (40) acting directly on the shaft (35) and provided with at least one cam (36) that acts on the supporting member (13) to move the supporting member (13) and selectively bring the counter-blade (12) so as to cooperate with the blade (10).

Description

[0001] The present invention relates to a device for cross-cutting web materials.

[0002] The device according to the invention is particularly advantageously used as a cutter for treated paper materials and specifically decorative paper impregnated and/or coated with polymeric resins, used to manufacture floor panelling or surfacing of furniture, walls, etc. It is, however, understood that the device according to the invention can also be used in other applications and/or to cut other materials.

[0003] According to commonly-used solutions, the webs of impregnated or coated decorative papers are cut into sheets by means of rotary cutters having two synchronized rotating rollers, arranged one above the other and provided with respective mutually cooperating blades. One inconvenience of these solutions, which can be observed especially at high machining speeds and with certain types of paper, is that the cut sheet is sucked back by the lower roller, blocking the cutter and thus the entire production line.

[0004] Other solutions known in the prior art comprise an upper blade carried by a rotating roller and a lower counter-blade that is cyclically raised towards the blade by pneumatically operated solenoid valves. These solutions, besides being relatively complex and expensive to produce and use, are not however suitable for high-speed machining, due to the time needed to actuate the solenoid valves.

[0005] An object of the present invention is to provide a cutting device that overcomes the drawbacks of the prior art described above; in particular, an object of the invention is to provide a device for cutting web materials that is simple to produce and use and completely efficient and reliable even at high machining speeds.

[0006] The present invention relates to a cutting device such as defined in its essential terms in claim 1 and, in its secondary features, in the dependent claims.

[0007] The device according to the invention is simple and relatively economical to produce and use, and is at the same time completely efficient and reliable even at high machining speeds. Moreover, with respect to the solutions known in the prior art, with the device according to the invention the distance between the blade and counter-blade can easily be adjusted, a significant reduction can be achieved in the turbulence in the cutting area (due to the fact that the stroke of the counter-blade can be very short), the speed of rotation of the blade and operation of the counter-blade can be adjusted and controlled separately.

[0008] Further characteristics and advantages of the present invention will become clear from the following description of a non-limiting embodiment thereof, with reference to the figures in the accompanying drawings, in which:

• figure 1 is a schematic front elevation view of a cutting device according to the invention;
• figures 2 and 3 are cross-sectional views along the line II outlined in figure 1, in which the device according to the invention is shown in respective operating positions.

[0009] In figures 1 and 2 designated as a whole by number 1 is a device for cross-cutting a web material 2, in particular a paper material such as decorative paper impregnated and/or coated with polymeric resins, to be used for instance to manufacture floor panelling or surfacing of furniture, walls, etc.

[0010] The material 2 is fed to the device 1 along a feeding direction D by means of a feed system 3 that is of a known kind, for example of the type having rollers 4 (which may or may not be motor-powered) between which the material 2 passes. The material 2 enters the device 1 through an entrance 5; the device cuts the material 2 crosswise with respect to the feeding direction D to form a plurality of sheets 6 that leave the device 1 through an exit 7 to be stacked in a specific stacking station, of a type that is known and not illustrated, arranged downstream of the device 1.

[0011] The device 1 comprises a blade 10 carried by a roller 11 that rotates about an axis R of rotation, a counter-blade 12 carried by a movable supporting member 13, and an actuator system 14 that brings the blade 10 and the counter-blade 12 so as to cyclically cooperate with one another.

[0012] The roller 11 is supported rotatingly about the axis R by a frame 15 of the device 1; the roller 11 is motor-powered, being driven by a motor 16; in particular, opposite axial ends of the roller 11 are provided respectively with a driving shaft 17 and a pin 18 inserted in respective bearings 19 carried by the frame 15. The shaft 17 is connected to the motor 16 by means of a reduction gear 20 and a transmission 21, for example comprising a toothed belt 22 mounted on pulleys 23. According to an alternative embodiment that is not illustrated, the motor 16, for example a torque motor, acts instead directly on the shaft 17.

[0013] The roller 11 has a longitudinal slot 28 that houses the blade 10; the blade 10 extends longitudinally along the roller 11, substantially parallel to the axis R or slightly curved, for example helically wound.

[0014] The member 13 faces the roller 11 and extends longitudinally substantially parallel to the roller 11; the roller 11 and the member 13 are arranged on opposite sides of the material 2 crosswise with respect to the material 2 and to the feeding direction D.

[0015] The member 13 is longitudinally elongated and can be variously shaped, for instance in the form of a roller-shaped member, a box-shaped member, a substantially prismatically-shaped member, etc.

[0016] The member 13 is pivotally attached to the frame 15 by means of a pair of pins 29 having longitudinal extremities supported by respective bearings 30 carried by the frame 15. The member 13 is pivoted with respect to an axis A of oscillation defined by the pins 29 and substantially parallel to the axis R of rotation of the roller 11; the member 13 has a pair of extremities 31, 32 arranged on opposite sides of the axis A.

[0017] The counter-blade 12 consists of a longitudinal blade shaped so as to cooperate with the blade 10 to cut the material 2 along a line substantially orthogonal to the feeding direction D. The counter-blade 12 projects in a cantilevered fashion from the extremity 31 of the member 13 towards the roller 11.

[0018] The actuator system 14 comprises a rotating shaft 35, substantially parallel to the axis R and to the axis A and provided with at least one cam 36 that acts on the member 13 to move the member 13 and selectively bring the counter-blade 12 so as to cooperate with the blade 10. In particular, the cam 36 is integrally attached to the shaft 35 and rotates integrally with the shaft 35 cooperating up against a contrast member 37, for example substantially cylindrical, carried by the extremity 32 of the member 13 and arranged substantially parallel to the axis A.

[0019] Clearly, although in this description reference is made to a single cam 36, the shaft 35 may also be provided with several cams 36 arranged along the shaft 35 and all cooperating with one single elongated contrast member 37 or with respective contrast members 37 arranged at a distance from one another.

[0020] The cam 36 is provided with a centred portion 38, having a smaller curvature radius, and an eccentric portion 39 having a larger curvature radius.

[0021] The shaft 35 is driven by a motor 40, preferably a brushless motor, that acts directly on the shaft 35; the shaft 35 is thus connected directly to a drive shaft 41 of the motor 40, with no reducers.

[0022] The shaft 35 and the roller 11 are driven respectively by the motor 40 and by the motor 16, which are independent of one another and both controlled by an electronic control unit 42 which synchronizes the operation of the two motors 16, 40 and receives signals from sensors, encoders or transducers (that are known and not illustrated for the sake of simplicity) connected to the roller 11, to the shaft 35 and/or to the member 13.

[0023] The shaft 35 is rotatingly supported, by means of bearings 43, by the frame 15, which also carries the motor 40.

[0024] The actuator system 14 also comprises one or more tensioning members 44 acting on the extremity 32 of the member 13 to maintain the member 13 in a predetermined position; in the figures only a single tensioning member 44 is illustrated, but it is understood that there may be two or more tensioning members 44 arranged at intervals along the member 13 parallel to the axis A and to the shaft 35.

[0025] In particular, the tensioning member 44 is an elastic member, for example a pneumatic spring comprising one or more set pressure bellows-type pneumatic pistons.

[0026] The cam 36 and the tensioning member 44 are arranged on opposite sides of the member 13 and specifically of the contrast member 37 and thus exert opposing forces on the member 13.

[0027] The member 13 oscillates between a rest position, shown in figure 2, in which the counter-blade 12 is detached from the material 2 passing through the device 1, and a cutting position, shown in figure 3, in which the counter-blade 12 is in contact with the material 2 and cooperates with the blade 10 to cut the material 2.

[0028] The tensioning member 44 maintains the member 13 in the cutting position and the cam 36 acts on the member 13 against the action of the tensioning member 44, in particular compressing the tensioning member 44, in order to move the member 13 into the rest position. The cam rotates by 180° to move the member 13 alternatively into the cutting position and into the rest position.

[0029] The device 1 also comprises a system 45 for adjusting the initial position of the member 13 and thus of the counter-blade 12 with respect to the frame 15 and thus to the blade 10. The system 45 is substantially of a type known and is therefore not described or illustrated in detail for the sake of simplicity.

[0030] The operation of the device 1 for cutting the material 2 into sheets is as follows.

[0031] The strip of web material 2 is fed to the device 1 by means of the feed system 3. The member 13 is in the rest position, since the cam 36 contacts the contrast member 37 with the eccentric portion 39 and pushes the member 13 against the action exerted by the tensioning member 44.

[0032] In order to perform the cutting operation, the control unit 42 sends a command to make the shaft 35 rotate by 180°, which brings the cam 36 into contact with the contrast member 37 with the centred portion 38. The tensioning member 44 is no longer contrasted by the cam 36 and thus moves the member 13 into the cutting position. Meanwhile, the roller 11 rotates in synchronization with the movement of the member 13. The control unit 42 controls the motors 16 and 40 synchronizing the rotation of the roller 11 provided with the blade 10 with the rotation of the shaft 35 and thus the alternating oscillatory motion of the member 13 with the counter-blade 12. The blade 10 and the counter-blade 12 are thus cyclically brought so as to cooperate with one another and cut the sheets 6.

[0033] The shaft 35 always turns in the same direction driven by the motor 40, while the member 13 oscillates alternately about the axis A in opposite directions.

[0034] Preferably, but not necessarily, the shaft 35 and the roller 11 rotate in the same direction and thus the blade 10 and the counter-blade 12 are brought into contact with the material 2 with a simultaneous rotary movement.

[0035] Lastly, it is clear that further modifications and changes may be made to the cutting device described and illustrated herein without departing from the scope of the attached claims.

Claims

1. Device (1) for cross-cutting web materials, comprising a blade (10) carried by a roller (11) that rotates about an axis of rotation (R), a counter-blade (12) carried by a movable supporting member (13), and an actuator system (14) to bring the blade and the counter-blade so as to cooperate cyclically with one another; the device being characterized in that the actuator system (14) comprises a rotating shaft (35) provided with at least one cam (36) that acts on the supporting member (13) to move the supporting member (13) and selectively bring the counter-blade (12) so as to cooperate with the blade (10).

2. Device according to claim 1, characterized in that the shaft (35) that carries the cam (36) is driven by a motor (40) acting directly on the shaft (35).

3. Device according to one of the previous claims, characterized in that the supporting member (13) that carries the counter-blade (12) is pivoted with respect to an axis of oscillation (A) and oscillates between a rest position and a cutting position.

4. Device according to claim 3, characterized in that the shaft (35) rotates in a predetermined direction and the cam (36) converts the rotary motion of the shaft (35) into alternating motion of the member (13), which oscillates alternately about the axis A in opposite directions.

5. Device according to claim 3 or 4,
characterized in that the cam (36) rotates by 180° to bring the supporting member (13) alternately into the cutting position and into the rest position.

6. Device according to one of the previous claims, characterized by comprising at least one tensioning member (44) that acts on the supporting member (13) to maintain the supporting member (13) in a cutting position; the cam (36) acting on the supporting member (13) against the action of the tensioning member (44) so as to bring the supporting member (13) into a rest position.

7. Device according to claim 6, characterized in that the tensioning member (44) is an elastic member and the cam (36) acts by compressing the tensioning member (44).

8. Device according to claim 6 or 7,
characterized in that the tensioning member (44) is a pneumatic spring comprising one or more set pressure bellows-type pneumatic pistons.

9. Device according to one of the previous claims, characterized in that the shaft (35) provided with the cam (36) and the roller (11) that carries the blade (10) are driven by respective independent motors (40, 16), both motors (40, 16) being controlled by a control unit (42) that synchronizes the operation of the two motors (40, 16).

Drawing