GB2258992A - A device for cutting continuous cigarette rods in cigarette manufacturing machines - Google Patents

Abstract

A continuous cigarette rod emerging from a typical manufacturing machine is divided into discrete lengths by a rotary cutter (3) fitted with at least one blade (4) disposed helically in relation to the feed axis of the cigarette rod (2) and operated in conjunction with a reaction element (8) mounted to a slide (5) comprising a fixed component (5a), and a movable component (5b) with which the reaction element (8) is rigidly associated; supported and guided by the fixed component (5a), and caused by a drive mechanism (7) to reciprocate parallel with the cigarette rod (2), the movable component (5b) is carried by a frictionless bearing system (6) interposed and interfacing the two components (5a, 5b) of the slide in such a manner as to disallow contact between them, at least while the movable component (5b) is in motion. <IMAGE>

Description

2 2 -k 13)) 12 1 A device for cutting continuous cigarette rods in

cigarette manufacturing machines

The present invention relates to a device for cutting continuous cigarette rods in cigarette manufacturing machines. The prior art in this field embraces the process of fashioning one or more continuous cigarette rods for subsequent division into discrete lengths. The cigarette rods pass through the machine and are cut without being brought to a standstill, in such a way as to avoid reducing the production tempo. This can be achieved by means of a rotating blade, for example, which exhibits a helical profile in relation to the axes of the continuous cigarette rods in order to ensure that the rods are severed by a faultlessly transverse cut. By calculating suitable values in respect of the lead angle of the blade, hence the helical pitch, and of its angular velocity in relation to the feed velocity of the cigarette rods, it becomes possible to obtain a perfect transverse cut without fraying or tearing the paper and the tobacco filler.

2 is To produce a faultless cut, however, a striking or reaction element must be provided to interact with the blade. since the cigarett-e rods themselves are certainly not able to offer a resistance sufficient to withstand the force of the cutting stroke. Naturally enough, the movement of the striking or reaction element must be correctly timed with that of the blade and of the cigarette rod, to suit the geometry and operating speed of the cutting edge. A preferred means of investing the reaction element with the correct movement consists in a slide type mechanism substantially comprising a first fixed component and a second movable component, supported and guided by the fixed component, with which the striking or reaction element is rigidly associated. The movable component of the slide mechanism is reciprocated by suitable means in the direction of movement of the cigarette rods between two limit positions, at a velocity at least equal to that of the rods, i.e. equal inasmuch as the two velocities will be strictly matched during the movement that coincides with the cutting stroke proper, whereas the return of the movable component to an initial limit position might be brought about at a greater velocity. Moreover, the time taken by the movable S 3 component to cover the distance between its two limit positions, which corresponds in practice to a portion of the pitch generated.by the cutting edge, must be strictly matched to the time taken by the blade in covering the selfsame distance, since any mismatch will result in unwanted contact between the cutting edge and the reaction element. The reaction element is constructed generally by embodying the movable component of the slide with a portion that extends toward the blade and affords a number of holes corresponding to the number of the cigarette rods, through which the rods are fed, and a slot or notch disposed transversely to the holes in a position such as to accommodate the movement of the blade as it cuts through the rod or rods. Various problems are encountered in construction of the movable component of the slide mechanism, which must be able to alternate at high speed. The slide reciprocates at a considerable.velocity, in effect, and the continuous cigarette rods must absolutely not be soiled by the lubricant normally utilized to ensure the regular motion of the movable component. This signifies that the lubricant must satisfy two essentially incompatible requirements: on the one hand for a fluid medium, applied in abundance, such 4 as will allow sliding movements to be effected at high speed, and on the other for an almost solid medium, exiguously applied du to the proximity of the cigarette rods. The practice with devices currently in use is to incorporate bearing elements that are either able to achieve the necessary reduction in friction with sparing quantities of lubricant, or constructed to a completely sealed design-. In either case, the results obtained hitherto have not been entirely satisfactory, and tend not to be in proportion with the costs incurred. The object of the present invention is to overcome the drawbacks described above in connection with the prior art. The stated object is realized in a device according to the invention for cutting continuous cigarette rods in cigarette manufacturing machines, which is of the type comprising rotary cutting means with at least one blade disposed helically in relation to the feed axis of at least one cigarette rod and in such a way as to intercept the rod, reaction means operating in conjunction with the cutting means and affording a passage to the cigarette rod, a slide consisting in a fixed component and a movable

1 component with which the reaction means are rigidly associated, and drive means by which the movable component of the slide is caused to reciprocate in the feed direction of the continuous cigarette rod, supported and guided by the fixed component, and characterized in that it further comprises support and guide means interposed and operating between the movable and fixed components of the slide, of which the function is to disallow contact between the movable component and the fixed component at least when the movable component is reciprocated by the drive means and in operation. The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which: -fig 1 is a schematic representation of the cutting device according to the present invention, viewed in side elevation and in a first embodiment; -fig 2 is the section through IIII of fig 1; -fig 3 is the schematic representation of a second embodiment of the cutting device according to the present invention, viewed in plan from beneath; -fig 4 is the section through IV-IV of fig 3; -fig 5 and fig 6 illustrate two further embodiments of the device, viewed in the sections through II-II 6 of fig 1 and IV-IV of fig 3, respectively; fig 7 and fig 8 illustrate two further embodiments of the device, both viewed in the section through II- II of fig 1, of which the embodiment of fig 8 is enlarged in relation to the remaining drawings. Referring to the accompanying drawings, a device 1 according to the invention for cutting continuous cigarette rods in cigarette manufacturing machines is of the type comprising cutting means 3, reaction means 8 operating in conjuction with the cutting means 3, and drive means 7 by which the reaction means 8 are set in motion. Taking as a reference direction the feed direction of the cigarette rod or rods 2 (which may be considered as being one only, given that a second rod will be parallel to the first), the cutting means 3 consist in a drum 9 supported and rotated about an axis which in the example of the drawings is disposed parallel to the feed direction of the cigarette rod 2, but might also be skew, and at least one blade 4 disposed helically in relation to the rod 2; typically, the blade 4 is mounted to the revolving surface of the drum 9 as shown in figs 1 and 3. As discussed at length in the foregoing preamble, the reaction means 8 must be capable of movement, 7 generated synchronously with that of the blade 4 and the cigarette rod 2, of which the timing is determined by the geometry anj operating speed of the blade 4. The reaction means 8 are invested with the correct movement by translation means embodied as a slide 5 consisting substantially in a fixed component Sa and a movable component denoted 5b, with which the reaction means 8 are rigidly associated, supported and guided by the fixed component 5a. In practice, the reaction means 8 are embodied by fashioning the movable component 5b of the slide 5 with a portion extending toward the cutting means 3 and affording at least one hole through which to direct the continuous cigarette rod 2 (in effect, the holes will be equal in number to the number of rods), also a slot or notch 13 lying transverse to the holes, through which the blade 4 passes during the cutting stroke. The movable component 5b of the slide 5 is invested with reciprocating movement, by the drive means 7, in a direction parallel to the feed direction of the cigarette rod 2. In the drawings, and particularly in figs 1 and 3, the drive means 7 are shown as a simple connecting rod 10 pivotably anchored to the movable component 8 5b of the slide 5 at one end and to a crank 11 at the other, mounted to a supporting frame 12 (shown only in part) which carries the cutting means 3. The movable component 5b is thus set in motion by the drive means 7 synchronously with the rotation of the cutting means 3, in such a manner that the blade 4 is caused to pass cyclically through the slot 13 of the reaction means 8. In practice, the reaction means 8 can be embodied either integrally with the movable component 5b of the slide 5, or as a separate part mounted to the movable component 5b. 6 denotes means interposed and operating between the movable component 5b and the fixed component 5a of the slide 5, of which the function is to support and guide the movable component 5b; more exactly, the action of the support and guide means 6 ensures that, during its reciprocating movement at least, the movable component 5b will-not come into contact with the fixed component 5a, and accordingly, all manner of friction and rubbing contact between the two components is eliminated. In the embodiment of figs 2 and 4, the support and guide means 6 consist in bearing means 60 capable of generating a magnetic field.

c 9 Such means 60 consist in magnets denoted 16 and 17, of which the magnetic properties might be either temporary or permanent. In the former instance, use would be made of electromagnets, and in the latter instance permanent magnets, as illustrated in the drawings. More exactly, the permanent magnets 16 and 17 are rigidly associated (see fig 2 and fig 4) respectively with an arm or appendage 14 of the movable component 5b and with arms or guides 15 afforded by the fixed component 5a of the slide 5. Arranged thus, the magnets 16 and 17 are able to interact, generating identical repulsion fields on both sides of the slide 5 which enable the movable component 5b to pass along the fixed component Sa without touching. Clearly, the fields generated by the magnets 16 and 17 might equally well be of attraction, albeit such a solution would be more complicated in embodiment. In figs 3 and 4, the movable component 5b of the slide 5 exhibits two parts 50, creating two arms or appendages 14 positioned between respective arms 15 of the fixed component 5, which also presents two discernible parts 51. Each of the appendages 14 and each of the arms 15 carries a respective magnet 16 and 17.

Similarly in this embodiment, the like poles of the magnets 16 and 17 associated with each one of the appendages 14 and the arms 15 are arranged so as to correspond and thus to repel one another. In this manner, each appendage 14 occupies a position of balance between the respective arms 15, disallowing contact between the fixed and movable components of the slide. In the embodiment of fig 1 and fig 2, which shows the movable component 5b of the slide 5 mounted to further guide means 19 consisting for example in a rod 19, rigidly passing through and guide means described above and the movable disallow mutual associated with the frame 12 and the movable component 5b, support 6 affording the same features as are interposed between the rod 19 component 5b in such a way as to contact between the two elements thus mechanically associated. It will therefore be evident that when the magnetic field type bearing means 60 are activated, the movable component 5b of the slide 5 is maintained in a state of balance in relation to the fixed component 5a and, when reciprocated by the drive means 7, prevented altogether from entering into contact with the latter.

11 The embodiments of figs 5 and 6 differ from the preceding examples described solely in that the support and guide means 6 cons-ist in a cushion of pressurized fluid denoted 61. As discernible from the figures in question, the part of each arm 15 facing the corresponding appendage 14 affords a chamber 20 connecting with a source of compressed air 21. When the source of compressed air 21 is activated, as with the magnets, the appendage 14 of the movable component 5b of the slide 5 remains in a state of balance, prevented from entering into contact with the arms 15 of the fixed component Sa. Figs 7 and 8 show further alternative embodiments of the cutting device; in particular, that of fig 7 comprises an additional magnet 16 associated with bottom part of the appendage 14 of the movable component 5b of the slide 5, which interacts with a corresponding magnet 17 associated with the fixed component Sa in such a way as to afford a greater measure of stability to the movable component 5b. In addition, the support and guide means 6 which separate the rod 19 from the movable component 5b consist in an air cushion 61 generated from the source 21 (not shown in fig 7) by way of a flexible tube 23.

12 Fig 8, on the other hand, illustrates the option of fitting magnets 16 to the faces of the rod 19 in such a way as to interact with-magnets 17 fitted to corresponding surfaces of the movable component 5b of the slide 5. This solution likewise enhances the state of balance induced in the slide 13 claims 1) A device for cutting continuous cigarette rods in cigarette manufacturing machines, comprising rotary cutting means with at least one blade disposed helically in relation to the feed axis of at least one continuous cigarette rod and in such a way as to intercept the rod, reaction means operating in conjunction with the cutting means and affording a passage to the cigarette rod, a slide consisting in a fixed component and a movable component with which the reaction means are rigidly associated, and drive means by which the movable component of the slide is reciprocated in the feed direction of the continuous cigarette rod, supported and guided by the fixed component, characterized in that it further comprises support and guide means interposed and operating between the movable and fixed components of the slide, of which the function is to disallow contact between the movable component and the fixed component at least when the 1 14 movable component is reciprocated by the drive means and in operation.

A cutting device as in claim 1, wherein the movable component of the slide comprises at least one arm or appendage slidably accommodated by a respective guide afforded by the fixed component, and support and guide ineans interposed and operating between the appendage of the movable component and the guide of the fixed component of which the function is to disallow contact between the appendage and the guide at least when the movable component is reciprocated by the drive means and in operation.

A cutting device as in claim 2, wherein the movable component of the slide exhibits two partscreating two arms or appendages, and the fixed component presents two parts affording arms or guides between which the respective arms or appendages of the movable component are slidably accommodated.

4) A cutting device as in claims 1, 2 and 3, wherein support and guide means operating between the movable and fixed components of the slide consist in means capable of generating a magnetic field.

5) 6) 7) 8) A cutting device as in claim 4, wherein the means capable of generating a magnetic field aremeans having temporary or permanent magnetic properties.

A cutting device as in claims 1, 2 and 3, wherein support and guide means operating between the movable and fixed components of the slide consist in a cushion of pressurized fluid.

A cutting device as in preceding claims, further comprising additional guide means along which the movable component of the slide is reciprocated, and support and guide means interposed between the additional guide means and the movable component of the slide of which the function is to disallow contact between the additional guide means and the movable component at least when the movable component is reciprocated by the drive means and in operation.

and operating A device for cutting continuous cigarette rods in cigarette manufacturing machines, substantially as described with reference to one or more of the figures of the accompanying drawings.