ITGE960004A1 - DEVICE FOR MAKING PARTIAL OR COMPLETE CUTS AND ENGRAVINGS IN TAPES OF PAPER MATERIAL, PLASTIC MATERIAL, FOIL, OR - Google Patents

Abstract

A device for making cuts and incisions, partial, or complete in strips of paper, plastic, foil, or the like, includes at least a knife (11, 12) or any further scoring tool and a counter-knife (5) or a any other co-operating striker tool, at least one of which, is supported rotatably and between which the material web (15) is passed. According to the invention, one of the two cooperating cutting, carving or engraving tools (11, 12, 5), in particular the knife (11, 12), can be moved alternately, preferably by oscillation in an active position and in one inactive position and it is stationary during the cutting, engraving, or similar action exerted in cooperation with the other tool, that is the counter-blade (5), while this rotates with a speed significantly higher than that of continuous belt sliding (15) of material between the two tools (5, 11, 12).

Description

DESCRIPTION of the industrial invention entitled "Device for making partial or complete cuts and incisions in strips of paper material, plastic material, foil, or the like."

TEXT OF THE DESCRIPTION

The invention relates to a device for making partial or complete cuts and incisions in strips of paper material, plastic material, foil, or the like, comprising at least a knife or any further scoring tool and a counter-knife or any other cooperating striker tool, of which at least one, is supported in rotation and between which the strip of material is made to pass.

In particular, the invention relates to devices of the aforesaid type for preparing and separating sheets of packaging wrapping in cigarette packing machines, or the like.

With particular reference to the aforementioned cigarette packing machines, the sheet of foil which is wrapped around the cigarettes to form the inner envelope of the packet is cut from a continuous strip of foil. The tape has a predetermined width and is commensurate with the axial length of the cigarettes, while the sheet is separated with a transversal cut made by means of a knife and an associated counter-knife. Furthermore, in particular in rigid packets, the area of the leaflet corresponding to the opening on the front and upper side of the box must be easily separated from the remaining part of the leaflet in order to access the cigarettes when the packet is first opened. Therefore, the sheet must have at least one predetermined tear line consisting of a partial notch parallel to the axis of the cigarettes and at least one partial notch transversal to the axis of the cigarettes and which connects with the latter.

The devices currently in use for the execution of said partial cuts or notches comprise both rotating knives and counter-knives which have such relative speeds, so that said cuts, partial cuts or incisions, have a certain inclination with respect to the direction perfectly perpendicular to the longitudinal axis of the belt. Furthermore, when it is necessary to vary the format in length of the sheet, and in particular but not only, in the case of shorter sheets for the smaller packs of cigarettes, the ratio between the relative speeds of the cutting means and the speed of advancement of the tape is such that the cutting or engraving means can cause bursts in correspondence with the cutting or engraving line and / or possibly also damage to the sheet. The damage can be particularly serious, when the cut is not complete, but the knife is made in such a way as to make a series of partial cuts separated by material bridges, or predetermined breaking lines. Furthermore, in machines with rotating knives and counter-knives, in order to ensure correct synchronization between the knives and counter-knives and the belt itself, even in the event of a change in the format of the sheet, it is necessary to vary the diameter of the circular path on which the knife and / or counter knife. This variation in the diameter of the path of the knife or counter-knife affects the sizing of the supporting means of the same. These in fact generally consist of rotating drums which are supported cantilevered on axes or shafts and whose dimensional reduction involves a decrease in the stability of the support. A lower support stability of the knife and counter-knife causes inaccuracies in the positioning of the two cooperating tools which affect their duration and which can also result in unclean, defective or partial cuts, as well as damage to the tools themselves.

The invention aims at realizing a device of the type described at the beginning, with which, thanks to relatively simple and inexpensive measures, it is possible to obviate the above drawbacks, guaranteeing a high perfection of cutting, carving, engraving, etc. always correct use of tools and an effective and simple adaptability to different formats without compromising the operational functions and the quality of the results.

The invention achieves the aforementioned objects with a device of the type described at the beginning, in which one of the two cooperating cutting, carving or engraving tools, in particular the knife, can be moved alternately, preferably by swinging it into an active position. and in an inactive position and is stationary during the cutting, engraving, or similar action exercised in combination with the other tool, that is the counter-blade, while the latter rotates continuously with a speed significantly higher than that of the continuous sliding of the belt of material between the two tools.

According to an improvement, in the case of the execution of two cuts, two incisions or the like of different lengths, in different points of the tape, such as for example for the separation and preparation of a wrapping sheet with a tear-off part, so-called clean , two knives are provided which are mounted on the same supporting means and in an alternatively oscillating manner in an operative position of cooperation with at least one single counter knife which is supported rotatably on a circular path around an axis parallel to the axis of oscillation of the two knives .

The rotation speed of the counter-knife and the oscillations of the knives are established in relation to each other and with respect to the speed of sliding of the belt between them in such a way, so that the knives and the corresponding counter-knife cooperate with each other, exerting the desired action on the tape at the predetermined points.

Advantageously, the knife (s) and the counter knife (s) are peripherally mounted on cylindrical or substantially cylindrical drums which are respectively driven in alternative rotation for a predetermined arc of a circle and continuously around their axes.

The knife-holder drum and the counter-knife drum have diameters much lower than the thickness of the material strip, while the knives protrude to such an extent, so that the distance between the cutting blade of the same and the peripheral surface of the drum counter-knife is slightly greater than the thickness of the strip and substantially of the order of magnitude of the radial protrusion of the counter-knife blade from the peripheral surface of the associated supporting drum, i.e. of the measure necessary to exert the cutting, notching, etching action etc. expected.

In particular, the counter-blade drum is made suction at least in one area of its extension and the suction power, i.e. the depression is adjusted in such a way as to hold the band of material against its peripheral surface, allowing the drum itself to perform a relative sliding movement on the belt which is operated at a lower sliding speed.

Thanks to the above measures, the invention effectively obviates the drawbacks due both to the presence of incorrect relative speeds of the cutting tools with respect to each other and with respect to the belt and to the instability of the supports of the cutting tools in the event of changes in formats. . Since the counter-knife drum rotates at a speed greater than that of the belt, and since the knife is stationary, the relative speeds between knife and counter-knife are very high. The cut is carried out without any accompanying effects occurring and with such rapidity, compared to the speed of sliding of the belt that allows to obtain an orientation of the cut with very low divergences from the orientation perfectly perpendicular to the length extension of the belt. Furthermore, the rapidity of the cut allows to avoid the effects of bending or damaging the sheet along the cutting lines. All this while guaranteeing the perfect execution of a scissor cut, in which the knife and the counter-knife always cooperate substantially theoretically and in good approximation on a single point of their extension in length, which point moves during the passage of the knife on the counter knife from one to the other end of the same.

In particular, interference between the knives and the counter knife (s) and the cutting line of the sheet from the belt are effectively avoided thanks to the particular sizing of the supporting drums of the tools. In fact, since the distance of the blades of the knives is slightly greater than the thickness of the belt, when the counter-knife is not in the position of cooperation with one of the two knives, the oscillation of the same in the operating position does not involve any contact or in any case any action on the belt. of material that flows adherent by suction against the counter-knife drum and slightly spaced from the cutting blade of the knives. Thanks to the fact that the counter-blade drum is made of suction and that it rotates at a speed higher than the sliding speed of the belt itself, at the moment of the separation of the sheet from the belt, this is held on the drum and accelerated forward with respect to the belt itself. The leading edge of the belt is offset backwards with respect to the cutting edge of the counter knife which moves faster than the belt itself. The sheet just cut, however, moves away from the cutting edge of the stationary knife, corresponding to the curvature of the peripheral suction wall of the counter-knife drum, being accelerated after cutting, at the speed of the counter-knife and maintaining its relative position with respect to it, so the rear edge of the sheet - with reference to the sliding direction of the rotation belt of the counter-knife drum - does not interfere with the cutting edge of the counter-knife itself.

With an appropriate dimensioning of the speeds it is possible to obtain an operating setting, in which the activation of the two knives is alternated between them, without interposing rest phases, simply by oscillating the knife drum with the predetermined rhythm in the angular position of activation now of the one and now of the other of the two knives.

Naturally, the definition of knife and counter-knife or of any further tool and of the corresponding matching tool in the description and in the claims is purely relative, it being possible to provide as an alternative to what has been described, a pair of supported counter-knives oscillating alternately in an operative position and cooperating with a single knife mounted protruding on the periphery of a continuously rotatable support drum.

The invention has further improvements which are the subject of the subordinate claims.

The characteristics of the invention and the advantages deriving from them will become clearer from the following description of a non-limiting executive example, illustrated in the attached drawings, in which:

Fig. 1 shows a schematic view of the device according to the invention.

Fig. 2 shows a section of the device according to fig. 1 according to a plane passing through the axes of the two knife-holder and counter-knife-holder drums.

Fig. 3 shows an enlarged axial section of the two drums according to fig. 2, with a knife and the counter knife in the operative position.

Fig. 4 schematically illustrates the inclination of the mutual orientation of the blades of the knives and counter-knives for obtaining a scissor cut.

Fig. 5 illustrates a sheet with cuts made transversally, for shearing and partial breaking pre-established for the detachment of the cleaner and which cuts are made with a device according to the previous figures.

With reference to fig. 1, a device for making partial or complete cuts and incisions in strips of paper material, plastic material, or the like, in particular in foil strips and in cigarette packing machines, has a first suction drum 1 which is rotatably mounted around to its axis on a drive shaft 3 supported by the frame 4. Peripherally, the drum 1 carries a cutting tool, in particular a counter knife 5 which is arranged with the cutting edge 105 oriented substantially parallel to the rotation axis of the drum 1 The counter-blade 5 is supported in an elastically yielding way thanks to springing means which can be of any type and which in the executive example are constituted by an element 305 of suitable material, particularly metallic, and with a predetermined intrinsic elasticity, and in which are made of slots 205 passing transversely to the axis of rotation and elongated in the axial direction. The counter knife 5 is supported with its cutting edge 105 protruding to a certain extent radially out beyond the peripheral shell surface 101 of the drum 1. Furthermore, the drum 1 is made of suction, being provided with a plurality of radial holes 201 which communicate with a distribution chamber 301 which extends in the manner of a cylindrical sector with a predetermined angular width. In correspondence with the external head side of the drum 1, the distribution chamber 301 is open and adheres to rotation and tightly against an annular sole 6 which has at predetermined points some holes 106 for connection alternatively to a source of depression and to atmospheric pressure or to a source of pressure and which holes are arranged at the same radial distance as the distribution lever 301 of the drum 1.

Advantageously, to favor the centering of the drum 1, the shaft 3 is made of a frustoconical shape, and tapers towards its end on the free front side of the device. In this area it has an extension 103 with which it engages in a freely rotatable way thanks to bearings 7 in a door 8 provided with a holding handle 108 and which can be locked in a removable way, for example thanks to clamping means 9, to a front plate 104 which is integral with the frame 4 of the device. Thanks to this expedient, the drum 1 can easily be disassembled from the device to perform, for example, adjustments or replacements of the counter knife, simply by releasing the flap 8 and then removing the drum 1 from the frusto-conical shaft 3; all without requiring complex centering steps.

Directly alongside, in particular below, the first drum 1 is provided a further drum 10 for carrying knives.

The knife holder drum is supported similarly to the counter knife holder drum 1 in a removable way on a drive shaft 16 and its housing is closed on the front side of the device by a removable door 8 'which carries a support bearing 7 rotation of a front extension 116 of the shaft 16, while the removable door 8 'is fixed by means of screws to the front plate 104 of the frame 4.

On the knife holder drum 10 are mounted with a radial orientation and in two different angular positions, two knives 11, 12. The knives can be assembled in the usual way thanks to clamping means 13, while the knives 11, 12 are supported adjustable relative to the radial position of their cutting edge 111, 112, for example thanks to a threaded pin 14 oriented radially and acting as a movable abutment against the radially internal side of the blades 11, 12.

The knives 11, 12 are oriented with their cutting edges 111, 112 in a position substantially parallel to the axis of the knife drum 10. In particular, as shown in fig. 4, in order to obtain a scissor cut, the knives and / or the counter knife are oriented slightly offset from each other and / or with respect to the axis of the relative drum 1, 10.

The distance of the axis of the knife holder drum 10 from the axis of the counter knife drum 1 is such that when the counter knife 5 does not cooperate with one of the two knives 11, 12, the strip of material 15 runs on the counter-knife holder drum 1 and is held adherent against it by the suction, passes slightly spaced from the blades of the two knives 11, 12 in any position they may be.

The counter knife 5, on the other hand, protrudes outwards from the peripheral suction skirt of the drum 1, to such an extent as to push the belt 15 against the knife respectively in an operative position.

The two drive shafts 3 and 16 of the two drums 1, 10 extend backwards and connect with their opposite ends to those supporting the drums 10 and the transmission means which are driven by the same motor, not shown. The shaft 3 of the counter-knife holder drum 1 is operated in continuous rotation by means of a gear chain 17 which also drives an oscillator with parallel axes 18 whose output shaft 118 is dynamically connected to the drive shaft 16 of the holder drum. -knives 10. The parallel axis oscillator 18 operates, in a synchronized manner with the rotation of the counter-knife drum 1, the knife-holder drum 10 with an alternative rotary motion of such angular amplitude and frequency, so that one of the two knives 11, 12 is brought alternately with respect to the other in the rest position and in the operative cutting position.

Thanks to the distance of the web of material 15, during the oscillation of the knife drum 10, the knives 11, 12 do not come into contact with the web 15, so that this does not risk being damaged.

With reference to fig. 5, in a cigarette packing machine, the two knives 11, 12 can be used to make a blanking cut T1 of the sheet F from the strip 15 and to make a cut in an intermediate point of said foil F partial tearing T2 of a part P of the foil F, the so-called pulì. In this case, the cut T2 does not extend over the entire width of the strip of material 15 and is not continuous along its extension, but has material jumpers in substantially equidistant positions.

As can be seen from figs. 3 and 4, therefore, in this case two knives are mounted on the knife-holder drum 10, one 12 for carrying out the continuous transversal cut TI for shearing the sheet F from the belt 15 and the other 11 which is shorter, for the realization of the partial T2 tear-off cut of the P.

To ensure the correct sliding speed of the belt 15, which is slower than the suction drum 1 and counter-knife holder, so as to ensure correct positioning of the partial cut T2, the corresponding knife li is first brought into the operative position, while subsequently the drum 10 is oscillated into the operative angular position of the knife 12 for the subsequent execution of the blanking cut T1.

From figs. 3 and 4 it is also evident that the knife 12 for carrying out the blanking cut TI has a continuous cutting edge 112, while the knife 11 for carrying out the predetermined tear cut of the cleaner P has a cutting edge 111 provided at regular distances of indented notches.

The speeds of actuation of the two drums 1, 10 and of the sliding of the belt 15 are adjusted in such a way that the knife-holder drum 10 is brought alternately continuously and without rest steps from the operating position of a knife 11, to the operating position of the other knife 12. This is allowed by the fact that the belt moves slower than the peripheral speed of the counter-knife drum 1. The length format of the sheet F is determined by the advancement speed of the belt 15, while the speed of the counter-knife holder drum 1 and the ratio of the same to the frequency of the reciprocating rotary motion of the knife holder drum 10 determines the relative position of the two cuts TI, T2.

When the counter-knife holder drum 1 is dynamically constrained to the speed of advancement of the belt 15, in the sense that it always has a speed twice the speed of the belt 15, then, for any speed of advancement of the belt and therefore for any format of the belt the two cuts T1, T2 will always have substantially identical positions on the sheet F.

Naturally, the invention is not limited to the embodiment with only two knives 11, 12 and a single counter-knife 5. In fact it is possible to provide also more counter-knives and / or more knives that cooperate with each other in the same way, in particular it is possible to provide in alternatively or in combination with the knives and counter-knives also of the different engraving tools, or the like.

The invention, in fact, is not limited to the embodiments just described and illustrated, but can be modified above all constructively without for this abandoning the guiding principle described above and claimed hereinafter.

Claims (15)

CLAIMS 1. Device for making partial or complete cuts and incisions in strips of paper material, plastic material, foil, or the like, comprising at least a knife (11, 12) or any other scoring tool and a counter knife (5) or any other cooperating striking tool, of which at least one, is supported rotating and between which the strip (15) of material is made to pass, characterized in that one of the two tools (11, 12, 5) for cutting, carving or mutually cooperating incision, in particular the knife (11, 12), can be moved alternately, preferably by oscillation in an active position and in an inactive position and is stationary during the cutting, incision or similar action exercised in cooperation with the other, or with the counter knife (5), while said other tool (5) rotates continuously with a speed significantly higher than that of continuous sliding of the strip (15) of material between the two u tensile (5, 11, 12). 2. Device according to claim 1, characterized in that in the case of the execution of two cuts (Tl, T2), two incisions or the like of different length, in different points of the belt (15), such as for example for the separation and preparation of a wrapping sheet (F) with a tear-off part, so-called pulì (P), two knives (11, 12) are provided which are mounted on the same support means (10) and can be alternately oscillated in position operative cooperation with at least one counter knife (5) which is supported (1) rotatable on a circular path around an axis parallel to the axis of oscillation of the two knives (11, 12). 3. Device according to claims 1 or 2, characterized in that the speed of rotation of the counter knife (5) and the frequency of oscillation of the knives (11, 12) are established in relation to each other and to the speed of sliding of the belt ( 15) between them in such a way, so that the knives (11, 12) and the corresponding counter knife (5) cooperate with each other, exerting the desired action on the belt (15) at the predetermined points. 4. Device according to one or more of the preceding claims, characterized in that it can have one or more knives (11, 12) and one or more counter knives (5). 5. Device according to one or more of the preceding claims, characterized in that the knife (s) (11, 12) and the counter knife (s) (5) are peripherally mounted on cylindrical or substantially cylindrical drums (10, 1) which are actuated respectively alternately rotating for a predetermined arc of a circle and continuously around their axes. 6. Device according to one or more of the preceding claims, characterized in that the knife-holder drum (10) and the counter-knife drum (1) have diameters which are decidedly lower than the thickness of the strip of material (15), while the knives (11, 12) protrude to such an extent that the distance between their cutting blade (111, 112) and the peripheral surface of the counter-blade drum (1) is slightly greater than the thickness of the belt (15) and substantially of the order of magnitude of the radial protrusion of the blade (105) of the counter-blade (5) from the peripheral surface (101) of the associated drum (1), that is, of the measure necessary to exert the cutting, carving, engraving, etc. action. provided, while the counter-knife-carrying drum is made suction in correspondence with its peripheral cylindrical surface (101) and at least in some areas. 7. Device according to claim 6, characterized in that the counter-knife holder drum (1) is made of suction (201, 301) at least in one area of its extension and the suction power, i.e. the depression is regulated so as to holding the strip of material (15) against its peripheral surface (101), allowing the drum (1) itself to perform a relative sliding movement on the belt (15) which is operated at a sliding speed lower than the rotation speed of the said counter-knife drum (1). 8. Device according to one or more of the preceding claims, characterized in that the knife-holder and counter-knife-holder drums (10, 1) are dynamically connected to each other by a transmission (18) with a fixed ratio and which transforms the continuous rotary motion of the counter-knife drum (1) in reciprocating rotary motion and with a predetermined frequency and annular amplitude of the knife-holder drum (10), while the rotation speed of the counter-knife drum (1) is linked to the sliding speed of the belt (15). 9. Device according to one or more of the preceding claims, characterized in that the knife-holder (10) and counter-knife-holder (1) drums are extractable mounted on drive shafts (3, 16), which are also supported at their ends (103, 116) on the free front side of the device, since said supports consist of doors (8, 8 ') fixed in a removable way (9) to the frame (4, 104), or to the front wall of the same. 10. Device according to one or more of the preceding claims, characterized in that the counter-knife and knife-holder drums (1, 10) and the support shafts (3, 16) of the same are provided with complementary automatic centering members. 11. Device according to claim 10, characterized in that the support shafts (3, 16) of the knife drum (10) and / or of the counter-knife drum (1) are made tapering conically towards the front front side of the device provided with removable doors (8, 8 '), while the drums (1, 10) themselves have truncated cone through seats for engagement on said shafts (3, 16). 12. Device according to one or more of the preceding claims, characterized in that the counter-knife drum (1) is made of suction (203., 301) at least in the area substantially facing towards the knife drum (10) and up to a sheet unloading area (F), in which it is connected to atmospheric pressure or is blowing. 13. Device according to one or more of the preceding claims, characterized in that the knives (11, 12) and / or the counter-knives (5) are made adjustable in relation to their axial and radial position, while they are oriented towards each other and / or respectively to the rotation axes, so as to perform a scissor cutting action with the blades (111, 112, 105). Device according to one or more of the preceding claims, characterized in that the counter knife (5) and / or the knives (11, 12) are supported radially and elastically spring. 15. Device for making partial or complete cuts and incisions in strips of paper material, plastic material, foil, or the like, in whole or in part as described, illustrated and for the purposes set out above.