DEVICE FOR THE SELECTIVE OR SIMULTANEOUS TRAVERSE OF THE CUTTING MEMBERS IN A MACHINE FOR THE CHOPPING AND/OR CUTTING OF MATERIAL IN SHEET

Abstract: Device for the selective or simultaneous traverse of the cutting members in a machine (10) for the chopping and/or cut­ ting of material in sheet, supported by supporting and slip beams (20), comprising: - two bar-formed elements (11, 12), mechanically interconnected, each parallel to the respective supporting and slip beams (20); - a motor (14) which drives the rotation of at least one of said elements (11, 12); - means of transformation (16) of the rotating movement of the bar-shaped elements (11, 12) in rectilinear traverse movement of each cutting member (17); and - means of energization and de-energization of said means of transformation.

Description: The present invention refers to a device for the selective or simultaneous traverse of the cutting members in a machine for the chopping and/or cutting of material in sheet. More in particular, the present invention concerns a device for the selective or simultaneous traverse of the position of circular knives and counterknives on the beams of a machine for the chopping and/or cutting of material in paper sheet. The need is noted, in the technical field, to vary the position of the operating members, generally knives and counterknives, on respective beams in machines for the abovementioned objects in relation to the required cutting and/or chopping sizes of the material submitted to this operation. It is also known that at present this positioning is performed in different ways, one of them being the motorization of each of the operative cutting members until same can traverse on the respective beam. This method of varying the position of the cutting members presents various problems of a constructive and economic nature. In fact, the structure of said members is rather complicated and the total cost of each operative member is high. Moreover, there is the problem of installing the supply cables of each motor, which may prevent good operation of the machine. Another noted method of positioning the operative cutting members consists in connecting them to devices cooperating with feed screws, whose rotations determine the traverse of the operative members. This method is also not without drawbacks, due to the fact that the structure is very complex; as each feed screw cooperates with clutches comprised in the respective devices, the cooperation between screw and clutches is not always reliable, and the various positionings of said operative members are controlled by numerous electronic and/or electric components in various positions, which further complicate the already complex structure of the machine. US-A-4 269 097 discloses a device for the selective or simultaneous traverse of the position of knives and counterknives in a machine for the chopping and/or cutting of sheet material, such as defined in the preamble of claim 1. However this known devices also has many drawbacks mainly due to the very complex and encumbering structure. The object of the present invention is to provide a device for the selective or simultaneous traverse of the position of knives and counterknives in a machine for the chopping and/or cutting of material in sheet, which does not present the abovementioned drawbacks and limitations. According to the present invention, this object is achieved by the features set forth in the characterizing part of claim 1. Particular embodiments of the device of the present invention are set out in the dependant claims 2 to 7. The device for the selective or simultaneous traverse of the cutting members in the form of knives and counterknives, supported on supporting slip beams, in a machine for the chopping and/or cutting of material in sheet, subject matter of the present invention, comprises: two substantially bar-shaped elements, each parallel to the respective supporting slip beams of the cutting members, said bar-shaped elements being mechanically interconnected; a motor which drives the rotation of at least one of said bar-shaped elements; means of transformation of the rotating movement of the bar-shaped elements into rectilinear traverse movement of each cutting member along the respective supporting slip beam; means of activation and/or de-activation of said means of transformation; wherein the means of transformation of the rotating movement of the bar-shaped elements into rectilinear traverse movement of each cutting member comprises: a shaft, corresponding to each cutting member, at substantially right angles to the supporting slip beam and equipped at one end with a pinion which engages in a rack on a supporting slip beam; a series of connecting means between the shaft and the bar-shaped elements, each of said connecting means has a cogged wheel torsionally fixed onto the respective bar-shaped element and a corresponding bush means with a toothed rim arranged on the shaft; and that said means of activation and de-activation comprises means for engaging and disengaging said bush means. The bush means comprise two-bushes inserted along the axis of the shaft, one of them being free to rotate around the shaft and being equipped with the toothed rim which engages at right angle with the cogged wheel of the bar-shaped element; and the other bush being torsionally fixed and axially mobile with respect to the first bush, along the shaft; the axial movement of the bush determining a torsional tie or clearance between the two bushes. The axially mobile bush has an upper part with larger diameter, contained in a chamber, and the axial movement is determined by the contrasting, opposing action of a compression spring and the adjustable pressure of a fluid poured into said chamber. The constructive and functional characteristics of the present device for the selective or simultaneous traverse of the cutting members will be more easily understood from the following detailed description, in which reference is made to the enclosed drawings which show a preferred, illustrative but not limitative embodiment of the present invention, and in which: fig. 1 shows a front schematic view of a machine for the chopping and/or cutting of material in sheet, equipped with traverse devices of the cutting members, according to the present invention; fig. 2 shows a lateral schematic view of a traverse device ofof the cutting members of the present invention; fig. 3 shows the schematic view of the section of the traverse device in fig. 2 and Fig. 4 shows the schematic view of the section of the device in fig. 3, made with a through-plane along line IV-IV. With reference to the figures, the machine 10 for the chopping and/or cutting of material in sheet, comprises a plurality of cutting members, each composed of a knife or blade 17 and a counterknife or counterblade 18, supported by beams 20, on which they can traverse. The traverse device of the cutting members of the present invention comprises two substantially bar-shaped elements, composed of shafts 11 and 12, which are mechanically interconnected, for example by a chain 13, and driven by a motor 14 which sets them in synchronous rotation around the respective axes. Said shafts 11 and 12, supported in rotable manner at the opposite ends of the machine casing, are equipped with longitudinal grooves 11' and 12' to fix, only torsionally, a plurality of cogged wheels 15 (see figs. 3 and 4), each of which is engaged, as specified later, with a device 16. To each of these devices 16 positioned on shaft 11 is fixed, in any known way, a knife 17, in this case circular, while to each of the devices 16 positioned on shaft 12 is fixed a counterknife 18, also circular. In the continuation of the present invention and with particular reference to figs. 3 and 4, a description will be given of only one of these devices 16 and more specifically one of those to which the knife 17 is fixed, the others, including those to which the counterknives 18 are fixed, being functionally and structurally similar. With reference to the abovementioned figures 3 and 4, the device 16 and knife 17 are slip supported, by a sliding means like rollers 19, by a supporting slip beam 20. This device 16 comprises a substantially cylindrical vertical structure 21, of compact size, in which a shaft 22 is inserted, partly projecting from said structure. The lower part of said shaft 22 is equipped with a pinion 23 which is engaged in a rack 24 with which the beam 20 is equipped. Along the axis of the shaft 22 are inserted two bushes 25 and 26, one an extension of the other. Of said bushes, the upper one 25 is torsionally fixed to said shaft 22 and axially mobile with respect to the lower bush 26. Said lower bush 26 is axially stationary and free to rotate on bearings 27 around the axis of the shaft 22. The bush 25 is so shaped that it terminates at the upper end with a portion 25' of larger diameter, seal sliding into a chamber 28, equipped with an opening 28', obtained in the vertical structure 21. At the lower end, said bush 25 is equipped with a projection or "tooth" 29. On this portion 25' of larger diameter is located a spring 30 which, acting against a "plug" 31 closing chamber 28, keeps said portion 25' in contact with the back wall of the chamber 28. The axially stationary lower bush 26 is shaped to form a toothed rim 32, constantly engaged at right angle in the cogged wheel 15, keyed on the shaft 11 and supported, by interposition of bearings 34, by shoulders 35 of the vertical cylindrical structure 21 of the device 16. The bush 26 is also equipped, in the upper part, corresponding to the bush 25 with a seat 36, to be engaged in the tooth 29 of the bush 25. When seat 36 is engaged in tooth 29, the shaft 22 and bushes 25 and 26 are torsionally fixed and therefore the rotation of the shaft 11 and cogged wheel 15 impose a rotation of the toothed rim 32 and, through the abovementioned torsional tie, on the pinion 23. The latter, being engaged in rack 24, causes a traverse of the device 16, along the beam 20, obtaining a new position of same. If, for sheet cutting reasons, any one or more of the knives 17 must not be repositioned, a flow of fluid, e.g. pressurized air, is inserted into chamber 28, through opening 28' which, acting against the spring 30, thrusts the portion 25' of the bush 25 axially upwards, operating like a piston with perimetral seal gasket 25'', and, thus, freeing tooth 29 from seat 36 of bush 26 (as shown in fig. 3). Bush 26 can thus freely rotate around the small shaft 22 which therefore, in this case, remains stationary, and device 16 therefore does not traverse along beam 20. Obviously the description of the devices to which knives 17 are connected also applies for the devices to which the counterknives 18 are associated, which, as already mentioned, are functionally and structurally similar. The structures of the supports of knives 17 and counterknives 18 being of known type are not described in detail. The traverse device of the present invention has been described and illustrated above solely by way of example but is cot binding; modifications and variants may therefore be made to same, e.g. the connection between devices 16 and shafts 11 and 12 could be made in a different way.

Claims: A device (16) for the selective or simultaneous positioning of cutting members in the form of knives (17) and counterknives (18) in a machine for the chopping and/or cutting of sheet material, in which the cutting members (17,18) are slip supported by respective beams (20), said device (16) comprising: two substantially bar-shaped elements (11,12), each parallel to the respective supporting slip beams (20) of the cutting members, said bar-shaped elements (11,12) being mechanically interconnected (13); a motor (14) which drives the rotation of at least one of said bar-shaped elements (11,12); means of transformation (15,32) of the rotating movement of the bar-shaped elements (11,12) into rectilinear traverse movement of each cutting member (17,18) along the respective supporting slip beam (20); means (25',30) of activation and deactivation of said means of transformation (15,32); characterized in that said means of transformation (15,32) of the rotating movement of the bar-shaped elements (11,12) into rectilinear traverse movement of each cutting member (17,18) comprises: a shaft (22), corresponding to each cutting member (17,18), at substantially right angles to the supporting slip beam (20) and equipped at one end with a pinion (23) which engages in a rack (24) on the supporting slip beam (20); a series of connecting means between the shaft (22) and the bar-shaped elements (11,12), each of said connecting means has a cogged wheel (15) torsionally fixed onto the respective bar-shaped element (11,12) and a corresponding bush means (25, 26) with a toothed rim (32) arranged on the shaft (22); and that said means of activation and deactivation (25',30) comprises means for engaging and disengaging said bush means (25,26). The device according to claim 1, characterized in that the shaft (22) is inserted into a cylindrical vertical structure (21) fixed to each cutting member (17,18) and the end of the shaft (22), opposite to that provided with the pinion (23), projects from said structure (21). The device according to claim 1 or 2, characterized in that the bush means comprise two bushes (25,26) inserted along the axis of the shaft (22); one of them (26) being free to rotate around the shaft (22) and being equipped with the toothed rim (32) which engages at right angles with the cogged wheel (15) of the bar-shaped element (11,12); and the other bush (25) being torsionally fixed and axially mobile, with respect to the first bush (26), along the shaft (22); the axial moving of the bush (25) determining a torsional tie or clearance between the two bushes (25,26). The device according to claim 3, characterized in that the torsional tie between the bushes (25,26) consists of a projection or "tooth" (29) at one end of the axially mobile bush (25) and a coherent seat (36) at the adjacent end of the other bush (26). The device according to anyone of the preceding claims, characterized in that the axially mobile bush (25) is equipped at the end opposite that of the tooth (29) with a portion (25') of larger diameter which seal slides into a chamber (28) obtained in the cylindrical structure (21) and has the function of piston; a spring (30), located on the portion (25') of larger diameter, holds the two bushes (25,26) in torsional tie position; said chamber (28) being equipped, below the portion (25') of larger diameter, with an opening (28') through which a flow of a fluid under pressure can be inserted which, acting against the spring (30), axially moves the movable (25) bush freeing it from the torsional tie with the axially stationary bush (26). The device according to anyone of the preceding claims, characterized in that the two substantially bar-shaped elements (11,12) are composed of shafts of substantially circular section, each of which presents longitudinal grooves (11', 12') to torsionally tie the connection means (15,16). The device according to anyone of the preceding claims, characterized in that the axially stationary bush (26) rotates on bearings (27) around the axis of the shaft (22) and is supported, by interposition of bearings (34), by the shoulders (35) of the cylindrical structure (21).

Inventors: CAVAGNA, ELIO
Applicants: CAVAGNA, ELIO
Application year: 1987
Main classification: B26D7
IPC codes: B26D7, B26D1