CUTTING-OFF MACHINE FOR THE CUTTING OF LOGS OF SHEET MATERIAL AND RELATIVE CUTTING METHOD

Abstract

Disclosed is a cutting-off machine for cutting logs of sheet material, including at least one cutting blade placed on a plane perpendicular to the axis of the logs, in order to perform transverse cuts over the same and produce rolls of smaller length than the logs, wherein the at least one cutting blade is associated with an ultrasonic device apt to generate a vibrating force on the blade.

Claims

1. Cutting-off machine (10) for cutting logs (13) of sheet material, comprising at least one cutting blade (11) placed on a plane perpendicular to the axis of the logs (13), in order to perform transverse cuts over the same and produce rolls (15) of smaller length than the logs, characterised in that said at least one cutting blade (11) is a rotating blade, with which is associated at least one sonotrode (23) of an ultrasonic device apt to transmit vibrational energy to the blade.

2. Cutting-off machine according to claim 1, wherein said rotating blade (11) is a disc carried by an orbiting arm, and said sonotrode (23) is placed on the axis (X) of the disc blade (11).

3. Cutting-off machine according to claim 1, wherein said rotating blade (11) is a disc carried by an orbiting arm (12), and said at least one sonotrode (23) is placed paraxial to the axis of the disc between the centre and the edge of said disc blade (11).

4. Cutting-off machine according to claim 1, wherein said rotating blade (11) is constituted by on purpose shaped flat blades (11) diametrically opposed, carried by a rotating support (12), and said sonotrode (23) is placed in correspondence to the base of the corresponding blade.

5. Cutting-off machine according to claim 1, characterised in that said ultrasonic device comprises an ultrasonic generator (20) linked by means of a cable (21) to an ultrasonic converter (22) and to said sonotrode (23) placed on the blade (11).

6. Cutting-off machine according to claim 1, wherein said sonotrode is a part of the mechanism responsible for the rotation of the blade.

7. Method for cutting logs (13) of sheet material by means of a cutting-off machine having at least one cutting blade (11) placed on a plane perpendicular to the axis of the logs, consisting in carrying said at least one blade into contact with said logs, or vice versa said logs into contact with said at least one blade to perform transverse cuts over the logs and to produce rolls (15) of smaller length than the logs, characterised in that said at least one cutting blade (11) is a rotating blade and ultrasounds are applied thereon during the cutting operation.

8. Method according to claim 7, wherein said rotating blade (11) is a disc carried by an orbiting arm (12) and said ultrasounds are applied on the axis (X) of the disc or in proximity of its edge.

9. Method according to claim 7, wherein said at least one rotating cutting blade (11) is constituted by on purpose shaped flat blades diametrically opposed and said ultrasounds are applied at the base of the respective blade.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Further features of the invention will be made clearer by the following detailed description, referred to its embodiments purely by way of a non-limiting example and illustrated in the accompanying drawings, in which:

[0020] FIGS. 1 and 2 are respectively a front view and a side view of a cutting-off machine with rotating disc blade mounted on orbiting arm, provided with a system of ultrasounds according to the invention applied at the centre of the blade;

[0021] FIGS. 3 and 4 are respectively a perspective view and front view of a cutting-off machine similar to that of the preceding drawings, with the ultrasounds applied on the edge of the blade;

[0022] FIG. 5 is a schematic perspective view of a cutting-off machine with two flat blades mounted on a rotating support, with ultrasounds applied at the bases of the blades; and

[0023] FIGS. 6, 7 and 8 are, respectively, a schematic perspective view, a front view and a side view of a cutting-off machine with multiple flat blades for passing cutting of the logs, with ultrasounds applied at the bases of the blades.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Referring to the accompanying drawings, and for the time being to FIGS. 1 and 2, a cutting-off machine for logs in sheet material, in particular paper, is shown schematically, denoted overall by reference numeral 10.

[0025] The cutting-off machine 10 is of the standard type, with rotating disc blade 11, mounted on an orbiting arm 12 so that the blade performs an orbit in a cutting plane perpendicular to the axis of the logs, denoted by reference numeral 13.

[0026] According to the embodiment of FIGS. 1 and 2, the logs 13 are made to move forwards in the direction of their axes in order to be taken under the cutting blade 11. Obviously, several cutting blades can be provided.

[0027] The drawings also show schematically a sharpening assembly 14 apt to sharpen periodically, and on indication of special sensors, the blade 11 as the latter wears out, if manufactured for example in metal. However, for what is stated here below, with the systems adopted by the invention, the wear of the blade is considerably reduced. Moreover, if special blades are used, for example in titanium, the sharpening assembly 14 can be absent.

[0028] According to the invention the cutting-off machine 10 is equipped with an ultrasonic device for causing the blade 11 to vibrate and improve the cut, eliminating the disadvantages illustrated previously.

[0029] The ultrasonic device, in the schematic form shown, comprises a generator of ultrasounds 20, connected by means of a cable 21, to an ultrasonic converter 22, coupled to a sonotrode 23.

[0030] However, the sonotrode could be part of the mechanism responsible for the rotation of the blade.

[0031] The ultrasonic converter 22 converts the electrical energy with frequency coming from the generator 20 into mechanical vibrations with high frequency, which are transferred to the sonotrode 23, which transmits the vibratory energy to the blade 11.

[0032] In the embodiment of FIGS. 1 and 2 the sonotrode 23 is mounted on the axis X of the blade 11, so that the ultrasounds are applied at the centre of the blade.

[0033] The provision of the ultrasounds, which make the blade vibrate, allows a very precise cut of the logs 13 to be made, avoiding overheating of the blade thanks to the reduced cutting force required by the vibration of the blade. The logs are not therefore deformed by the compression.

[0034] FIGS. 3 and 4, in which the same reference numerals introduced previously are used, illustrate an embodiment of the cutting-off machine wholly similar to that of FIGS. 1 and 2.

[0035] The only difference is that in this case the ultrasonic converter 22 and the sonotrode 23 are applied in proximity of the edge of the blade. Therefore, the vibratory force of the ultrasounds acts directly on the edge of the blade. Without departing from the scope of the invention, one or more sonotrodes can be provided, placed paraxial to the axis of the disc between the centre and the edge of the disc blade (11).

[0036] According to the embodiment of FIG. 5, the cutting-off machine comprises on purpose shaped flat blades, in particular two rectilinear flat blades 11 placed in diametrically opposed positions on a rotating support 12.

[0037] In this case the sonotrodes 23 are placed at the base of the blades 11.

[0038] According to the embodiment of FIGS. 6, 7 and 8, a plurality of fixed flat blades 11 are provided, against which the logs 13 are made to move forwards in a direction perpendicular to their axes, for a so-called passing cut.

[0039] For the transport of the logs a plurality of lower drive belts 30 are provided, and a corresponding plurality of opposite upper drive belts 31, placed between the plurality of blades 11.

[0040] In FIGS. 6 and 8, two logs moving forwards towards the cutting blades 11 are shown between the opposite series of belts 30, 31, one log at the cutting stage and one log already cut into rolls 15, with side trims 16.

[0041] In this case a plurality of ultrasounds generators 20 are provided, connected by means of respective cables 21 to corresponding ultrasonic converters 22 and sonotrodes 23 placed at the bases of the respective blades 11.

[0042] From what has been disclosed the advantages appear clear of the invention which, combining an ultrasonic device with a cutting-off machine of logs of sheet material of any known type, allows an extremely precise cut to be obtained, eliminating the disadvantages of the prior art linked to the overheating and deformation of the cutting blade.

[0043] Naturally the invention is not limited to the particular embodiments previously described and illustrated in the accompanying drawings, but numerous detailed changes may be made thereto, within the reach of the person skilled in the art, without thereby departing from the scope of the invention itself as defined by the appended claims.