Apparatus for perforating the wrappers of rod-shaped smokers' products and the like

Abstract

Tubular envelopes of successive rod-shaped products, such as cigarettes and/or filter rod sections, are caused to turn about their longitudinal axes and to simultaneously move sideways during advancement through a perforating station. At least one laser or another source of high-energy radiation directs at least one beam of radiation against a radiation-reflecting body which is caused to turn about its axis and has one or more curved, such as helical, surfaces serving to cause migration of and to simultaneously reflect the beam or beams upon one or more selected portions of the envelope of the rod-shaped product then moving through the perforating station. The thus refected beam(s) perforates or perforate the envelope being advanced through the station.

Description

CROSS-REFERENCE TO RELATED CASES

[0001] This application claims the priority of the commonly owned copending German patent application Serial No. 102 00 402.1 filed Jan. 8, 2002. The disclosure of the above-identified German patent application, as well as that of each US and/or foreign patent and/or patent application identified in the specification of the present application, is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] The invention relates to improvements in apparatus for providing selected portions of sheet-like wrapping material with regions or zones of desired permeability, and more particularly to improvements in apparatus for selecting the permeability of wrapping material for rod-like articles, especially rod-like articles of the tobacco processing industry. Still more particularly, the invention relates to improvements in apparatus wherein at least one rotary body is provided with at least one reflecting surface for at least one beam or ray of high-energy radiation which is directed against a moving sheet-like wrapping material while the body is caused to turn about its axis whereby the at least one beam perforates the sheet-like material. Still more particularly, the invention relates to improvements in apparatus wherein the at least one portion of the reflecting surface of the at least one rotary body is designed to ensure migration of the at least one beam which is being reflected thereby.

[0003] The rod-shaped articles of the tobacco processing industry the wrappers of which can be perforated in the apparatus of the present invention are intended to encompass all such articles the normally tubular wrappers or envelopes of which are intended to be perforated by one or more beams of energy-rich radiation during or subsequent to the making of the articles. Such articles include plain or filter cigarettes, filter mouthpieces, cigarillos, cigars, papyrossi and the like. The wrapping material for the contents (fillers) of such rod-shaped articles can consist of cigarette paper, other paper, uniting bands which are utilized to connect tobacco-containing rod-shaped articles (such as plain cigarettes) with filter mouthpieces, webs of coherent uniting bands made of so-called tipping paper such as artificial cork or the like and/or others. The perforating of such wrapping material can take place during or subsequent to unwinding of a continuous web or strip from a bobbin, reel or the like, subsequent to subdivision of the web or strip into discrete uniting bands and/or subsequent to convoluting of the continuous web or uniting band around a continuous rod-like filler of tobacco or filter material or subsequent to convoluting of discrete uniting bands around two or more coaxial rod-shaped tobacco- or filter material-containing products.

[0004] An important advantage of properly perforated tubular envelopes of requisite permeability is that at least the perforated sections of such envelopes exhibit a desired or optimum permeability which allows entry of atmospheric air into the column of tobacco smoke flowing through the envelope from the lighted end toward the mouth of the smoker. This exerts a desirable influence upon the percentage of nicotine and/or condensate in that part of tobacco smoke which enters the mouth and the lungs of the smoker. In addition, atmospheric air entering the column of tobacco smoke is considered by many smokers to exert a beneficial influence upon the taste of tobacco smoke.

[0005] As a rule, or in many instances, the source of energy-rich radiation which is resorted to in order to perforate the wrapping material for rod-shaped smokers' products including cigarettes, filters for tobacco smoke and filter cigarettes or the like constitutes or employs one or more lasers or other sources of corpuscular radiation. The beam or beams of radiation issuing from the laser or lasers is or are normally deflected by one or more lenses and/or other optical elements which causes or cause the beam or beams to impinge upon a moving wrapping material, e.g., upon a running web, upon running uniting bands or upon a running tubular envelope surrounding a cigarette, a cigarette filter and/or the like. It is desirable to ensure highly predictable influencing of permeability, i.e., uniform distribution of perforations in selected portion(s) of the running web, uniting band or tubular envelope and/or the making of perforations having a desired size and/or shape. Such circumstances should prevail during the making of long series of smokers' products, e.g., in a cigarette making machine which can turn out up to and in excess of 20,000 rod-shaped articles per minute.

[0006] Many presently known apparatus for making perforations in running webs or in running uniting bands and/or in rapidly advancing tubular envelopes often employ drum- or roller-shaped conveyors which are set up to transport the commodities to be perforated (e.g., the tubular wrappers of cigarettes or filter rod sections) sideways, e.g., at right angles to the longitudinal axes of the rod-shaped commodities. Such conveyors advance successive commodities through a perforating zone wherein the wrapping material is subjected to the action of one or more beams of energy-rich corpuscular radiation or the like. In order to enlarge the area of the sheet-like material which is to be perforated, it is customary to cause the tubular envelope of a cigarette, filter rod or the like to turn during transport through the perforating zone. Thus, a cigarette moving through the perforating zone is normally caused to move sideways (such as exactly at right angles to its longitudinal axis) and to simultaneously turn about such axis. The means for imparting to a cigarette a rotary movement about its axis can include a stationary or mobile surface which is in more or less linear contact with the cigarette in the perforating zone, or a roller which cooperates with the drum or an analogous conveyor that serves to move the cigarette sideways. The arrangement is often such that the conveyor which moves the cigarette sideways contacts the wrapper at one side of the longitudinal axis of the cigarette, and that the rolling surface contacts the cigarette substantially diametrically opposite the conveyor.

[0007] Many presently known perforating apparatus for the tubular wrappers of cigarettes, filter mouthpieces or the like are assembled in such a way that a drum-shaped conveyor moves a continuous series of cigarettes or like rod-shaped articles sideways, that a stationary or mobile rolling member causes successive rod-shaped articles of the series to turn about their respective axes, at least at the perforating station, and that each article is caused to complete a full 360-degree rolling movement about its axis during travel through the perforating station. Such arrangement ensures that the perforations in the selected portion of the tubular envelope are distributed along an arc of at least substantially 360°, i.e., that atmospheric air can enter the column of tobacco smoke in a smokers' article from all the way around such article. This can be achieved if each beam of radiation impinging upon the envelope of an article moving through the perforating station is caused to move relative to the station. Such task is performed by the aforementioned rotary body which is caused to turn about a predetermined axis. As a rule, the body is rotated by a discrete drive and is provided with a surface which reflects radiation issuing from the source, e.g., a laser, while the body rotates about the predetermined axis. The optical system focusses the moving beam upon the wrapping material at the perforating station so that the beam produces holes of desired shape, size and/or distribution. The reflecting surface(s) of the rotary body serves or serve as one or more mirros arranged to ensure migration of each deflected beam along a predetermined path defined by successive points of contact between the beam and the wrapping material. Such follow-up movements of the reflected beam(s) ensure highly predictable and rapid increase of permeability of selected portions of a continuous web, of a series of uniting bands or of a series of successive tubular wrappers.

[0008] It is to be noted that, as a rule, the radiation source is caused to modulate each beam. In most instances, such modulation involves pulsing of the beam or beams so that the enhancement of permeability involves the making of discrete holes in lieu of elongated (e.g., circumferentially extending) slots. The discrete holes can form two or more circumferentially extending and/or otherwise oriented rows. The pulse sequences are or can be adjustable to thus select the spacing between successive holes (perforations) of one or more rows; this enables the apparatus to provide the perforated portions of the webs, uniting bands and/or tubular envelopes with any one of a practically infinite number of different patterns of holes and/or other forms of perforations. Certain presently preferred variations involve the making of rows of circular perforations having variable sizes and/or shapes and/or spacings from each other. Furthermore, the rows of identical or different perforations can be placed nearer to or at greater distances from each other and/or they can extend circumferentially and/or longitudinally of the respective rod-shaped smokers' products such as plain or filter cigarettes, cigarillos, cigars and/or filter mouthpieces.

[0009] European patent No. 1 018 392 A2 discloses a perforating apparatus which is designed to make holes in the tubular envelopes of rod-shaped articles, particularly cigarettes. The patented apparatus comprises a light source which generates at least one high-energy beam serving to perforate the envelopes, a follow-up device for the at least one beam, a perforating station which is established by the follow-up device and wherein the envelope of a cigarette moving therethrough is perforated, means for causing a cigarette moving through the perforating zone to turn about its longitudinal axis and to thus expose a substantial part of its envelope to the action of the beam or beams, and means for transporting cigarettes through the perforating zone. The aforementioned follow-up device comprises at least one pivotable mirror. Prior to reaching the perforating zone, the at least one light beam is caused to pass through at least one light refracting unit which ensures that the at least one beam remains focussed upon the envelope within the entire perforating zone. Thus, the just described patented apparatus is capable of ensuring that the (migrating) beam or beams follows or follow a cigarette during travel through the perforating zone and to provide perforations extending circumferentially of the tubuar wrapper.

[0010] German patent No. 40 38 928 A1 proposes a cigarette perforating apparatus which employs a rotary member provided with a stepped peripheral surface. The steps or stages of such surface are parallel to each other and constitute deflecting mirrors for a laser beam which serves to perforate the wrappers of cigarettes. The beam is guided in such a way that it impinges upon the reflecting surface at an angle to the axis of the rotary member and that it is alternatingly deflected into different paths by the stepped portions of the peripheral surface, and such paths are parallel to each other. The just described arrangement ensures that the number of the thus obtained perforations matches the number of steps or stages in the peripheral surface of the rotary member. A drawback of such apparatus is that its versatility is rather limited, i.e., it can merely provide the envelope of a cigarette with perforations which are spaced apart from each other in the axial direction of the cigarette but the perforations cannot be distributed in the circumferential direction of the cigarette which is caused to move axially through the perforating station.

[0011] A further apparatus for the making of perforations in wrapping material which is to be converted into tubular envelopes of cigarettes or analogous rod-shaped products of the tobacco processing industry is disclosed in German patent No. 195 11 393 A1. This apparatus also comprises a rotary body which constitutes a polygonal mirror serving to cyclically deflect a laser beam through a predetermined angle while the body rotates. A series of neighboring optical elements are disposed next to each other in the path of the laser beam which is being deflected by the polygonal mirror, and each such optical element directs the beam upon a predetermined portion of the wrapping material. Thus, the envelope of a cigarette or the like which is confined in a portion of the thus treated wrapping material can be provided with several perforations the number of which matches the number of optical elements. During treatment (i.e., during the making of perforations), the wrapping material is spread out to lie flat upon a support and it must move relative to the perforating apparatus. A drawback of the just described apparatus is that the wrapping material must move through a separate perforating unit during a stage preceding the draping of such material around successive rod-shaped articles or around a continuous rod-like filler of tobacco or filter material for tobacco smoke. Moreover, the perforations in the tubular envelopes made of the thus treated wrapping material extend only longitudinally (axially) of the ultimate rod-shaped products.

[0012] To summarize: All of the aforediscussed conventional methods and apparatus exhibit the drawback that, even though they can provide discrete perforations in selected portions of the wrappers of cigarettes or the like, they are not designed to ensure continuous movements of a focussed laser beam or the like, especially while a rod-shaped article moves sideways, in such a way that the envelope of the article is provided with circumferentially extending perforations.

OBJECTS OF THE INVENTION

[0013] An object of the present invention is to provide a perforating apparatus wherein a beam of high-energy radiation, such as a laser beam, can be maintained in continuous motion by resorting to relatively simple kinematics.

[0014] Another object of the invention is to provide novel and improved beam guiding and modulating means between a laser or another suitable source of radiation and the material which is to be perforated.

[0015] A further object of this invention is to provide a novel and improved method of influencing one or more beams of corpuscular radiation or the like in a machine for the making of rod-shaped smokers' products.

[0016] An additional object of the instant invention is to provide a web perforating apparatus which can be installed in existing machines for the making of plain or filter cigarettes, filter mouthpieces and/or other rod-shaped products of the tobacco processing industry without necessitating any or any pronounced changes in the construction and/or mode of operation of such machines.

[0017] Still another object of the invention is to provide an apparatus which can form the wrappers of rod-shaped articles with zones of desired permeability in a simple, predictable and readily adjustable manner.

[0018] A further object of the invention is to provide novel and improved optical components for utilization in the apparatus of the above outlined character.

[0019] Another object of the invention is to provide a machine, such as a cigarette maker or a filter tipping machine, which embodies one or more apparatus of the above outlined character.

SUMMARY OF THE INVENTION

[0020] The invention resides in the provision of an apparatus which is set up to provide successive tubular envelopes or wrappers of rod-shaped products with regions of desired permeabilities while the envelopes advance through a perforating station, preferably by moving sideways and by simultaneously turning about their longitudinal axes. The improved apparatus comprises a source (such as a laser) which is arranged to emit at least one beam of high-energy radiation (such as a pulsating beam of corpuscular radiation), and a radiation-reflecting body which is rotatable about a predetermined axis and has at least one surface at least a section of which is curved (this term is intended to encompass bent, arched, arcuate and other configurations which are or which can be said to be curved) and is arranged to reflect and to cause simultaneous migration (such as periodic shifting or movement) of the at least one beam while the radiation-reflecting body rotates about the predetermined axis to thus direct the at least one beam against the envelope advancing through the perforating station with attendant (resulting) formation of perforations in the envelope.

[0021] The aforementioned section of the at least one surface is or can be strip-shaped.

[0022] In accordance with a presently preferred embodiment, the aforementioned section of the at least one surface is a helix. The axis of such helix is or can be at least substantially parallel to the (predetermined) axis about which the radiation-reflecting body rotates. Alternatively, the axis of the helix can at least substantially coincide with the predetermined axis. The source is or can be arranged to direct the at least one beam upon the at least one surface at a predetermined angle of incidence, and the axis of the helix can be at least substantially parallel to such beam.

[0023] The at least one surface is or can be inclined relative to the external surface of the radiation-reflecting body. Furthermore, the at least one surface can include a plurality of discrete curved sections, and such body can further include partitions between the sections. For example, each partition can include a step or an uneven part of the radiation-reflecting body. Each section can include first and second end portions which are respectively disposed in discrete first and second planes that are at least substantially parallel to each other. Such planes are or can be at least substantially normal to the (predetermined) axis of the radiation-reflecting body. The first and second planes of the first and second end portions of each of the sections are spaced apart from each other. The sections can be at least substantially uniformly distributed at the peripheral surface of the radiation-reflecting body. The sections can be at least substantially identical with each other regarding their shapes, directions and/or leads.

[0024] If the aforementioned section of the at least one surface is a helix, the lead of such helix with respect to the predetermined axis of the radiation-reflecting body is or can at least approximate 45°.

[0025] The source of high-energy radiation can include or constitute at least one laser, and such laser can be arranged to emit at least one beam of corpuscular radiation, particularly at least one pulsed beam of corpuscular radiation.

[0026] The source of high-energy radiation and the radiation-reflecting body can be installed in a machine for the making of rod-shaped smokers' products, e.g., in a filter tipping machine wherein plain cigarettes are assembled with filter rod sections of unit length or multiple unit length, in a cigarette making machine or in a filter rod making machine.

[0027] The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and the modes of assembling, installing and operating the same, together with numerous additional advantageous and important features and attributes theeof, will be best understood upon perusal of the following detailed description of certain presently preferred specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

[0028] FIG. 1 is a schematic front elevational view of a filter tipping machine which is equipped with permeability enhancing apparatus embodying one form of the present invention;

[0029] FIG. 2 is a schematic side elevational view of a rotary mirror-like radiation-reflecting body which can be utilized in the improved apparatus;

[0030] FIG. 3a is a schematic side elevational view of an apparatus which embodies one form of the present invention and employs a single radiation-reflecting body of the type shown in FIG. 2;

[0031] FIG. 3b is a transverse sectional view as seen in the direction of arrows from the line 3b-3b in FIG. 3a and shows a beam of high-energy radiation issuing from a laser forming part of the apparatus shown in FIG. 3a;

[0032] FIG. 3c is a sectional view of a modulated beam as seen in the direction of arrows from the line 3c-3c in FIG. 3a;

[0033] FIG. 3d is an enlarged elevational view of an optical element which is utilized in the perforating apparatus of FIG. 3a;

[0034] FIG. 4a is a front elevational view of a modified apparatus which employs two rotary radiation reflecting bodies and can be utilized for simultaneous making of rows of circumferentially extending perforations in the envelopes of two discrete or still non-separated rod-shaped products;

[0035] FIG. 4b is a side elevational view of the modified apparatus, as seen from the left-hand side of FIG. 4a; and

[0036] FIG. 5 shows a portion of a filter cigarette of double unit length and two pulsating beams of corpuscular radiation which are utilized in a filter cigarette making machine or the like to simultaneously form two circumferentially extending rows of perforations.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0037] The filter tipping machine of FIG. 1 is similar to that disclosed in commonly owned U.S. Pat. No. 5,135,008 granted Aug. 4, 1992 to Oesterling et al. for “METHOD OF AND APPARATUS FOR MAKING FILTER CIGARETTES” or to that disclosed in commonly owned U.S. Pat. No. 5,054,346 granted Oct. 8, 1991 to Heitmann for “APPARATUS FOR REPEATEDLY SEVERING RUNNING WEBS OF TIPPING PAPER AND THE LIKE”. The machine comprises a fluted rotary drum-shaped conveyor 1 mounted in a machine frame and receiving two rows of parallel plain cigarettes of unit length from a cigarette rod making machine, not shown, e.g., a machine known as PROTOS and distributed by the assignee of the present application. The conveyor 1 delivers the two rows of plain cigarettes to two fluted drum-shaped aligning conveyors 2 which serve to align each cigarette of one of the two rows with a cigarette of the other row and to deliver successive pairs of aligned cigarettes into successive peripheral flutes of a rotary drum-shaped assembly conveyor 3 in such a way that the cigarettes in the flutes of the conveyor 3 are spaced apart from each other.

[0038] The frame of the tipping machine further supports a magazine 4 for a supply of filter rod sections of six times unit length. The outlet at the bottom of the magazine 4 delivers filter mouthpieces into the axially parallel peripheral flutes of a rotary drum-shaped severing conveyor 6 which cooperates with two axially and circumferentially staggered rotary circular disc-shaped knives 7 to subdivide each filter moutpiece of six times unit length into three coaxial filter mouthpieces of double unit length and which delivers the thus obtained groups of three filter mouthpieces each into discrete conveyors of a composite rotary drum-shaped staggering conveyor 8. The latter staggers the three mouthpieces of each group in the circumferential direction and delivers them into successive axially parallel peripheral flutes of a rotary drum-shaped shuffling conveyor 9. The shuffling conveyor 9 cooperates with stationary cams or with driven belts (not shown) to convert the received filter plugs of double unit length into a row wherein each preceding filter plug is in exact alignment with each following plug, and successive filter plugs of double unit length of the thus obtained single row are inserted into the gaps between pairs of plain cigarettes of unit length in the flutes of the assembly conveyor 3 by a rotary drum-shaped accelerating conveyor 11. Thus, each of those flutes of the conveyor 3 which advance beyond the transfer station between the conveyors 3, 11 contains a group of three coaxial rod-shaped articles, namely, two plain cigarettes of unit length and a filter mouthpiece of double unit length between them.

[0039] The next step involves axial movement of at least one plain cigarette in each group of three rod-shaped articles toward the other plain cigarette so that the two plain cigarettes abut the adjacent end faces of the respective filter mouthpiece. Such condensed groups are admitted into successive axially parallel peripheral flutes of a rotary drum-shaped transfer conveyor 12. The latter is adjacent a rotary drum-shaped counterknife 19 of a severing apparatus which further includes a rotary knife carrier 21. Such severing apparatus serves to repeatedly sever a web 13 of coherent uniting bands (e.g., made of artificial cork) which are to be rolled around the filter mouthpieces of double unit length as well as around the adjacent end portions of the respective pairs of plain cigarettes of unit length being supplied by the transfer conveyor 12.

[0040] The web 13 is drawn off an expiring bobbin or reel 14 and is caused to advance past a customary curling device 17 having a relatively sharp edge which serves to enhance the ability of the running web to curl. Successive increments of the thus treated web 13 are advanced by a pair of cooperating entraining rollers 16 disposed ahead of a paster 18 serving to provide one side of the running web 13 with a film of a suitable adhesive, e.g., a hot melt. The web 13 is thereupon severed by the knives of the knife carrier 21 in cooperation with the counterknife 19 to yield a succession of discrete uniting bands each of which is caused to adhere to the oncoming group of three coaxial rod-shaped articles being delivered by the transfer conveyor 12. Actual convoluting of successive uniting bands around the respective groups of three coaxial rod-shaped articles each is carried out on a rotary drum-shaped rolling conveyor 22 in cooperation with a stationary or mobile rolling device 23.

[0041] The rolling conveyor 22 delivers the thus obtained successive filter cigarettes of double unit length to a rotary drum-shaped drying conveyor 24, and the latter transfers the filter cigarettes onto a rotary drum-shaped severing conveyor 26 which cooperates with a rotary circular knife 25 to sever each filter cigarette of double unit length midway across its filter mouthpiece of double unit length and to thus produce pairs of filter cigarettes of unit length. The severing conveyor 26 can cooperate with or include a device (not shown) which detects and segregates defective filter cigarettes of unit length or double unit length.

[0042] Successive pairs of coaxial filter cigarettes of unit length are taken over by a so-called turn-around device 29 which can be of the type disclosed in the aforementioned U.S. Pat. Nos. 5,135,008 to Oesterling et al. and 5,054,346 to Heitmann, or in U.S. Pat. No. 3,583,546 granted Jun. 8, 1971 to Koop for “APPARATUS FOR INVERTING CIGARETTES OR THE LIKE”. The apparatus 29 comprises a first rotary drum-shaped transfer conveyor 27. The latter delivers one filter cigarette of each pair directly to a second rotary drum-shaped transfer conveyor 28. The other filter cigarette of each pair is inverted end-for-end on its way from the conveyor 27 to the conveyor 28 so that the latter gathers a single file of filter cigarettes of unit length which move sideways and the filter mouthpieces of all of which face in the same direction. The conveyor 28 delivers successive filter cigarettes of unit length to the axially parallel peripheral flutes of a rotary drum-shaped testing conveyor 31, and the latter delivers successive tested filter cigarettes to a further drum-shaped conveyor 32 which can perform the dual function of ejecting those filter cigarettes which have been found to be defective during travel with the testing conveyor 31 and of carrying out one or more additional tests, e.g., to ascertain the density of tobacco-containing ends of successive filter cigarettes of unit length.

[0043] The conveyor 32 delivers satisfactory filter cigarettes of unit length into the range of a rotary braking device 33 before such cigarettes reach the upper stretch of an endless belt or band conveyor 36 being trained over several pulleys (one shown at 34) and serving to move the repeatedly tested filter cigarettes of unit length to a further processing station, e.g., into a packing machine such as a machine for the making of so-called hinged-lid packets normally containing arrays of twenty parallel cigarettes each.

[0044] A first source 37 of high-energy radiation (e.g., a laser which emits a pulsating beam of corpuscular radiation) is installed adjacent the drying conveyor 24, and a second such source 37 is shown adjacent the transfer conveyor 28. It is normally sufficient to employ a single radiation source or to install such radiation source adjacent to at least one drum-shaped conveyor in the tipping machine of FIG. 1. The source or sources 37 forms or form part of a novel optical apparatus which serves to provide the tubular envelopes or wrappers of successive filter cigarettes of unit length or multiple unit length with regions of desired permeability while the envelopes advance through the single perforating station or through the respective one of several perforating stations. Each of the two optical apparatus shown in FIG. 1 further comprises a rotary cylindrical radiation-reflecting body or mirror 44 which is shown in FIG. 2 and which is utilized in each of the embodiments respectively shown in FIGS. 3a-3d and 4a-4b. The means for rotating the radiation-reflecting body 44 about its axis 44a comprises a suitable drive, e.g., an electric motor. The arrangement is preferably such that, when the improved optical apparatus is in actual use, the body 44 is caused to rotate about its axis 44a at a constant speed.

[0045] FIG. 2 shows a presently preferred radiation-reflecting body or mirror 44, its longitudinal axis 44a and the pulsating radiation beam 38 issuing from the source 37 (not shown in FIG. 2) and propagating itself in the direction of and coinciding with the axis 44a. The beam 38 impinges upon and is reflected by the body 44. The peripheral surface of the body 44 is provided with a beam-reflecting surface including at least one curved strip-shaped portion or section 46 shown in FIG. 2 in the form of a helix. The beam 38 which is shown in FIG. 2 is reflected by the helical section 46 in such a way that it leaves in a direction at right angles to the axis 44a, i.e., radially of the reflecting body 44.

[0046] The helical or part helical strip-shaped section 46 of the corpuscular radiation-reflecting peripheral surface of the body 44 has an axis which coincides with the rotational axis 44a. Furthermore, the surface section 46 which is shown in FIG. 2 extends at right angles to the peripheral surface of the cylindrical body 44. The angle between the axis 44a and the impinging radiation beam 38 on the one hand, and the direction of deflection of the beam by the illustrated surface section 46 on the other hand is 90°. The laser 37 which emits the pulsating incoming beam 38 is assumed to be stationary, and the direction of propagation of the beam 38 coincides with or is parallel to the axis 44a. This beam is also stationary (i.e., it does not move sideways, it does not swivel or pivot, it does not oscillate and it does not carry out any other stray movements) because the laser 37 is stationary. All that counts is to ensure that the pulsating beam issuing from the laser 37 impinge upon the helical section 46 at the peripheral surface of the radiation-reflecting body or mirror 44. The arrow 48 denotes in FIG. 2 one possible direction of reflection of the incident beam 38 by the section 46.

[0047] The lead or pitch of the helical section 46 is preferably constant; this ensures that, when the body 44 is caused to turn about its axis 44a in the direction indicated in FIG. 2 by the arrow B, the reflected beam 48 travels or migrates through a certain distance in a direction from the starting end (first end portion) 46a to the other end (second end portion) 46b of the helical section 46 and moves transversely of its radiation axis. The thus covered distance matches or approximates the circumferential length of the tubular envelope or wrapper of a cigarette (such as a filter cigarette) which is then located at the perforating station defined, for example, in part by the drum-shaped conveyor 24 or 28 shown in FIG. 1.

[0048] It will be seen that the rotary movement of the body or mirror 44 must be synchronized with the rolling movement of the filter cigarette at the perforating station in such a way that the cigarette rotates (about its longitudinal axis) through 360° while the body 44 turns through an angle corresponding to that of the circumferentially offset end portions 46a, 46b of the helical section 46 relative to each other.

[0049] The lead of the helical section 46 shown in FIG. 2 is assumed to equal or at least approximate 45°. As already mentioned hereinbefore, the angle between the incident beam 38 and the reflected beam 48 is or approximates 90°. However, the just described angular relationships are not mandatory, i.e., the lead of the section 46 can depart from 45°, and the angle between the incident and reflected beams 38 and 48 can deviate from 90°.

[0050] FIG. 2 shows a relatively simple radiation reflecting body (44) the peripheral surface of which is provided with a single curved beam reflecting surface, namely the helical portion or section 46. However, the body 44 or an equivalent thereof can be provided with a composite curved radiation reflecting surface which includes two or more helical or similar sections identical with or analogous to the helical section 46 of FIG. 2. This will be described in detail with reference to FIGS. 4a and 4b wherein the radiation-reflecting body or mirror 44A is provided with four preferably identical helical portions or sections 46.

[0051] Referring now to FIGS. 3a to 3d, the rotary cylindrical body or mirror 44 is installed in a housing or deflector head 40 having an inlet 42 for the beam 38′ which is a modification of the beam 38 issuing from the laser 37. The beam 38 issuing from the laser 37 has an at least substantially circular cross-sectional outline (see FIG. 3b). This beam is caused to pass through an optical element 39 which changes its cross-sectional outline from circular to flat or linear as shown in FIG. 3c. The thus modified beam 38′ penetrates through the inlet 42 of the housing 40 and impinges upon the section 46 of the rotating radiation reflecting body 44. The latter can be identical with the aforedescribed body 44 shown in FIG. 2.

[0052] The optical element 39 of FIG. 3a can be omitted if the laser 37 is replaced with a source of high-energy radiation which embodies the element 39 or an equivalent thereof, i.e., if the substitute for the laser 37 of FIG. 3a can emit a beam having a cross-sectional outline matching, resembling or approximating that shown at 38′ in FIG. 3c.

[0053] The beam 48 which is reflected by the section 46 of the peripheral surface of the rotary body 44 in the housing 40 of FIG. 3a is caused to pass through a partly cylindrical lens 50 which focusses the beam 48 (the focussed beam is shown at 52) upon the envelope of a cigarette 60 (such as a filter cigarette of the type produced in the tipping machine of FIG. 1) then moving sideways through the perforating station PS established by a drum-shaped conveyor 70 rotating in the direction indicated by the arrow A. At the same time, the cigarette 60 dwelling at the perforating station PS is caused to turn about its own axis as a result of linear contact with one or more endless belts or bands 78 trained about pulleys 80, 81 at least one of which is driven to rotate clockwise, as viewed in FIG. 3a (see the arrow AA).

[0054] The axis of the partly cylindrical focussing lens 50 is normal to the direction of propagation of the reflected beam 48. This lens is shown in a sectional view in FIG. 3d; its purpose is to convert the incident linear beam 48 into the convergent beam 52 which impinges upon the tubular envelope of the rotating cigarette 60 then dwelling at the perforating station PS. The thus obtained row of perforations extends circumferentially of the envelope.

[0055] The drum-shaped conveyor 70 can constitute the rotary conveyor 24 or 28 in the tipping machine of FIG. 1, or one of several other conveyors, e.g., the conveyor 27 or 31. In order to ensure predictable advancement of cigarettes 60 toward and away from the station PS and turning of successive cigarettes 60 at the perforating station, the peripheral surface of the conveyor 70 is provided with circumferentially spaced-apart axially parallel and radially outwardly extending projections or ribs 72 each having a front side 77 and a rear side 76 (as seen in the direction of the arrow A). The front side 77 of any one of the ribs 72 and the rear side 76 of the immediately preceding rib 72 flank a convex portion 74 of the peripheral surface of the conveyor 70. The speed of the belt(s) 78 and the peripheral speed of the conveyor 70 are synchronized in such a way that a cigarette 60 which has been deposited on one of the surface portions 74 adjacent the trailing side 76 of the respective rib 72 moves with the side 76 to the station PS and dwells at this station until entrained by the oncoming front side 77 of the immediately following rib 72 upon completion of the perforating operation by the focussed beam 52.

[0056] The ribs 72 cooperate with the main portion of the conveyor 70 to define a series of preferably identical troughs each of which is bounded by a surface portion 74, by the front or leading side 77 of one of the respective ribs 72 and by the trailing side 76 of the other rib 72. It will be seen that, in FIG. 3a, the conveyor 70 is caused to rotate in a counterclock-wise direction (arrow A), and the pulleys 80, 81 for the endless belt(s) 78 are caused to turn in a clockwise direction (arrow AA).

[0057] A cigarette 60 which is delivered to a convex portion 74 of the peripheral surface of the drum-shaped conveyor 70 (e.g., by the conveyor 22 or by the conveyor 28 or 30 of FIG. 1) is attracted to the convex portion 74 at the respective trailing side 76 by suction or in any other suitable way. To this end, the conveyor 70 can be provided with rows of suction ports which are temporarily connectable to the suction intake of a fan or another suction generating device during each revolution of the conveyor. Reference may be had, for example, to commonly owned U.S. Pat. No. 4,825,882 granted May 2, 1989 to Hinz for “APPARATUS FOR ROLLING UNITING BANDS AROUND GROUPS OF ROD-SHAPED ARTICLES”.

[0058] Each filter cigarette 60 is deposited at and is attracted by suction against the trailing side 76 of one of the ribs 72 before such cigarette reaches the endless belt(s) 78. Suction is not applied while the cigarette contacts the belt(s) 78 and rolls along the convex surface portion 74 then at the perforating station PS away from the trailing side 76. Suction is again effective when the cigarette 60 is approached by the oncoming front side 77 of the next-following rib 72. The belt(s) 78 decelerates or decelerate the cigarette 60 which reaches the station PS by causing the cigarette to roll about its axis while dwelling within the range of the focussed beam 52. Upon completion of the perforating step, the cigarette 60 at the station PS is engaged by the oncoming front side 77 and is advanced (see the arrow A) beyond the station PS. The peripheral speed of the conveyor 70 exceeds the speed of the endless belt(s) 78.

[0059] That cigarette 60 which, in FIG. 3a, occupies the perforating station PS still abuts the trailing side 76 of the respective rib 72. This is not absolutely necessary; thus, the belt(s) 78 can engage and begin to roll a cigarette 60 along the respective convex surface portion 74 before the cigarette reaches the perforating station, e.g., in such a way that the cigarette which is being impinged upon by the focussed beam 52 is located between, for example, at least substantially midway between, the respective ribs 72.

[0060] Other modes of causing successive cigarettes 60 to dwell at the perforating station PS for required intervals of time are equally within the purview of the present invention. All that normally counts is to ensure that each cigarette 60 dwells at the perforating station PS and simultaneously turns about its axis for an interval of time which is required to enable the beam 52 to perforate the envelope of such cigarette all the way around the circumference of the envelope or along a selected angle.

[0061] It is also possible to replace the driven rolling belt(s) 78 with a stationary rolling member which contacts a cigarette 60 at the perforating station PS. Such arrangement is particularly desirable if there is no room at the perforating station for a relatively bulky cigarette rolling arrangement (such as the belt(s) 78, the pulleys 80, 81 and the means for driving at least one of the pulleys).

[0062] In accordance with still another modification, the optical element 39 can be replaced with a device which is capable of converting the circular laser beam 38 into a beam having a more or less point- or dot-shaped cross-sectional outline. This renders it possible to dispense with the optical element 50. Alternatively, the laser 37 can be designed in such a way that the beam which is being emitted thereby has a more or less dot-shaped cross-sectional outline. Such modifications might involve higher expenses for the sources of high-energy radiation.

[0063] A further presently preferred embodiment of the improved apparatus which can be utilized as a means for increasing the permeability of selected regions of tubular envelopes controlledly advancing through a permeability influencing (such as perforating) station is shown in FIGS. 4a and 4b. The radiation source (not shown in FIGS. 4a and 4b) can include a laser which emits a beam 38 impinging upon and being influenced by an optical element 39a constituting a collector lens. The convergent beam issuing from the lens 39a is thereupon influenced by two cylindrical radiation reflecting bodies or mirrors 44A and 45. The parts of the apparatus shown in FIG. 4a are turned through 90° relative to the parts of the aforedescribed apparatus which is shown in FIG. 3a. Thus, the axes 44a and 45a of the radiation reflecting bodies 44A and 45 extend at right angles to the plane of FIG. 4a. Furthermore, the beam 38 issuing from the laser forming part of the apparatus of FIGS. 4a and 4b is also normal to the plane of FIG. 4a. FIG. 4b is a view as seen from the left-hand side of FIG. 4a.

[0064] An advantage of the apparatus of FIGS. 4a and 4b is that it employs a collector lens 39a which is simpler than the lens 39. The radiation reflecting bodies 44A and 45 are arranged to rotate about their axes in directions which are respectively indicated by the arrows B and B′. Because this apparatus comprises two rotary radiation reflecting bodies 44A and 45, the non-illustrated radiation source and the collector lens 39a are designed in such a way that they produce two parallel beams 38 (see FIG. 4a). This can be readily accomplished by employing a collector lens 39a which comprises two neighboring lens segments or portions 39′ shown in FIG. 4a. The focal length of the composite lens 39a is selected in such a way that the focal point of the entire beam is clearly behind the body or mirror 44A, namely at a location where the convergent beam impinges upon the tubular envelope of an article (such as a cigarette 160) at the perforating station. Thus, the lens 39a converts the incoming laser beam into a convergent beam. However, it is also within the purview of the present invention to install the lens 39a directly in the laser that emits the beam 38 shown to the right of the lens 39a actually shown in FIG. 4b. Still further, it is clear that the apparatus of FIGS. 4a and 4b can also comprise a housing analogous to the housing 40 of FIG. 3a and serving as a deflecting head adapted to confine the radiation reflecting bodies or mirrors 44A and 45.

[0065] The bodies 44A and 45 of FIG. 4a are mirror images of each other with reference to a plane which is tangential to the peripheral surfaces of such bodies and extends between the two segments 39a′ of the collector lens 39a. This ensures that the two beams of the composite beam issuing from the laser and propagating themselves at right angles to the plane of FIG. 4a impinge upon discrete sections 46 of the composite reflecting surfaces of the bodies 44A and 45. Such beams are shown in FIG. 5, as at 52 and 54, and they are reflected by discrete mirrors 58. These reflected beams 52, 54 impinge upon axially spaced-apart portions of the envelope of cigarette 160 at the perforating station. The cigarettes 160 of FIGS. 4a, 4b and 5 are rod-shaped smokers' products of double unit length.

[0066] The cigarette 160-I which is shown in FIGS. 4a and 4b by solid lines is located at the inlet (receiving end) of the perforating station, and its longitudinal axis is spaced apart from the longitudinal axis of the parallel cigarette 160-II by a distance C. The cigarette 160-II (shown by broken lines) is disposed at the outlet (discharge end) of the perforating station. Sidewise movements of the cigarettes 160-I, 160-II in the course of the perforating action take place at an angle to the beams 52 and 54 (see FIG. 4b). The reason is that, during migration of the beams 38 due to rotation of sections 46 of the bodies 44A, 45, the path of the focal point is not normal to the focussed beams 52, 54 since, owing to reflection by the helical sections 46 at the peripheral surfaces of the bodies 44A, 45, the lengths of the reflected beams 48, 49 and of the focussed beams 52, 54 are changed accordingly.

[0067] As can be seen in FIG. 4a, each of the bodies 44A, 45 is provided with a composite surface including four equidistant strip-shaped curved (helical) sections 46. Each of the sections 46 extends along a fourth of a circle. Since the sections 46 of each of the bodies 44A, 45 are uniformly distributed at the peripheral surface of the respective body, they are disposed at angular distances of 90° relative to each other. The lengths, shapes, leads and orientations of all four sections 46 on each of the bodies 44A, 45 are identical. The first end portions 46a (see FIG. 2) and the second end portions 46b (refer again to FIG. 2) of all sections 46 are disposed in imaginary planes which are adjacent to or coincide with the respective end faces of the corresponding bodies 44A and 45. Furthermore, the end portions 46a and 46b are normal to the axes (44a, 45a) of the corresponding bodies 44A and 45.

[0068] Each stage of operation of the apparatus embodying the structure of FIGS. 4a and 4b involves a turning of the bodies 44A, 45 through angles of 90°, and each such stage involves rotation of a cigarette 160 about its own axis through an angle of 360° as well as a sidewise advancement (arrow A) through the distance C. The next stage involves a similar manipulation of the next-following cigarette while the bodies 44A, 45 again turn through 90°. Thus, the angular displacement (90°) of each of the two bodies 44A, 45 per treatment (perforation) of envelopes of the cigarettes 160 is related to the distance C which a cigarette must cover during treatment of its envelope by the focussed beam 52 or 54.

[0069] The laser beam 38 automatically reassumes its starting position as soon as the angular displacement of the bodies 44A, 45 through the angles of 90° is completed. In other words, the beam 38 then again impinges upon the first end portions 46a of the next sections 46 of the two bodies 44A and 45.

[0070] Since the beam 38 has a certain cross-sectional area, the useful angle of rotation per stage of operation of the apparatus shown in FIGS. 4a and 4b is somewhat less than the angular distance between a pair of neighboring sections 46. This is the reason for the provision of the collector lens 39a which reduces the diameter of and prefocusses the incident beam 38 to thus optimize the useful intervals of utilization of the laser, i.e., to optimize the useful distance of radiation of laser beam per working cycle.

[0071] It is to be noted here that the apparatus embodying the structure of FIGS. 4a and 4b is a so-called twin-beam embodiment which can be put to use to perforate the envelopes of cigarettes of double unit length. Such cigarettes can be produced in the machine of FIG. 1 wherein the conveyor 13 has axially parallel peripheral flutes each of which receives a pair of axially spaced-apart cigarettes of unit length and a filter mouthpiece of double unit length between them. These groups are transferred onto the conveyor 12 which cooperates with the counterknife 19 to apply to each group an adhesive-coated uniting band which adheres to the entire filter mouthpiece of double unit length and to the adjacent inner end portions of the respective plain cigarettes of unit length. The initial contact between a uniting band and the adjacent rod-shaped components of a filter cigarette of double unit length on the conveyor 12 is a mere straight linear contact, and such minimal contact is increased into full contact between the external surfaces of the three components and the adhesive-coated internal surface of the uniting band during travel of the three components and the uniting band with the rolling conveyor 22 past the stationary or mobile rolling device 23.

[0072] If the improved apparatus is to provide perforations in the envelopes of successive filter cigarettes of double unit length, the perforating operations can be carried out at a station defined in part by the drying conveyor 24 or by the conveyor 28 of the machine shown in FIG. 1. The beams 52, 54 (see FIG. 5) then impinge upon two axially spaced-apart portions of the envelope of each cigarette 160. The perforations 62, 64 provided by the two beams 52, 54 can form two circumferentially complete annuli, one in the envelope of one and the other in the envelope of the other of two filter cigarettes of unit length which are obtained as a result of halving each cigarette of double unit length on the conveyor 26.

[0073] The effect of the curved helical sections 46 of the composite radiation reflecting surfaces on the rotating bodies 44A, 45 is the same as that of an inclined surface which is shifted in a direction normal to its plane, except that the kinematics of a rotary mirror-like body 44A or 45 with helical sections 46 are much simpler. This will be appreciated by referring to FIG. 4b which shows, in addition to the progress of two helical sections 46, the corresponding leads by broken straight lines. The broken line also denotes the progress of the corresponding developed helical section 46 in the form of an inclined reflecting surface. FIG. 4b further shows that, owing to parallel shifting of such reflecting section from its starting position (indicated at 46-I) to its end position (denoted at 46-II), the reflected beam undergoes a sidewise movement, namely from an initial position (which is shown by solid lines and is denoted by the character 48-I), to an end position in which the beam is shown by broken lines and is identified by the reference character 48-II. The characters 52-I and 52-II respectively denote the beams 48-I and 48-II which are focussed by the mirrors 58. Still further, FIG. 4b shows that, after rotation of the body 44A in the direction of arrow B and through the prescribed angle is completed, there takes place an abrupt return movement of the beam 38 to the initial position of the next-following section 46 because the end position 46-I of the preceding section 46 coincides with the starting position 46-II of the next section 46.

[0074] The mirrors 58 are shown in FIGS. 4a and 4b for the sake of better illustration and for illustration in a space-saving manner. However, it is equally possible (especially if the required space is available) to omit the reflecting mirrors 58 and to cause the reflected beams 48, 49 to be focussed directly upon the envelope of the cigarette at the perforating station. Still further, it is also possible to employ the mirrors 58 or their equvalents in the apparatus of FIGS. 3a to 3d, especially if the available space renders such utilization of the mirrors 58 possible. It goes without saying that the apparatus of FIGS. 3a to 3d can operate with two rotary radiation reflecting bodies, such as the bodies 44A, 45 shown in FIG. 4a if this apparatus is set up to simultaneously perforate the envelopes of pairs of cigarettes, cigarillos or the like.

[0075] An important advantage of all embodiments of the improved apparatus is that the curved section or sections 46 of the rotary body or bodies (44 or 44A, 45) ensures or ensure a continuous shifting (migration) of the reflected beam or beams. This contributes to simplicity of the kinematics which are utilized to cause the beam or beams to continuously follow the prescribed path for optimal perforation of one or more portions of the envelope(s) at the perforating station. Therefore, the improved apparatus is particularly suited for use in connection with the making of predictable arrays of circumferentially extending perforations in cigarette making and like or analogous machines; all that is necessary is to ensure that the articles to be perforated move sideways.

[0076] Rotation of the body 44 or bodies 44A, 45 about its axis (44a) or about their respective axes (44a, 45a), and simultaneos rotation or orbiting of the curved section or sections 46 (such as one or more helical sections or their equivalents) about the respective axis or axes causes the incident beam or beams of high-energy radiation to propagate itself or themselves in parallelism with the axis or axes of the section or sections in a manner as if the beam or beams were to impinge at an angle upon a plane reflecting surface while the surface moves at right angles to its plane. The difference is that the means for controlling the propagation of the beam(s) in the apparatus of the present invention is much simpler and easier to control from the stand-point of kinematics, compactness and/or cost.

[0077] Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of the above outlined contribution to the art of perforating tubular envelopes and the like and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the appended claims.

Claims

1. Apparatus for providing successive tubular envelopes of rod-shaped products with regions of desired permeability while the envelopes advance through a perforating station, comprising:

a source arranged to emit at least one beam of high-energy radiation; and

a radiation-reflecting body rotatable about a predetermined axis and having at least one surface at least a section of which is curved and is arranged to reflect and to cause simultaneous migration of the at least one beam while said body rotates about said axis to thus direct the at least one beam against the envelope advancing through the perforating station with attendant formation of perforations therein.

2. The apparatus of claim 1, wherein said section of said at least one surface is strip-shaped.

3. The apparatus of claim 1, wherein said section of said at least one surface is a helix.

4. The apparatus of claim 3, wherein said helix has an axis which is at least substantially parallel to said predetermined axis.

5. The apparatus of claim 3, wherein said helix has an axis which at least substantially coincides with said predetermined axis.

6. The apparatus of claim 3, wherein said source is arranged to direct said at least one beam upon said at least one surface at a predetermined angle of incidence, said helix having an axis which is at least substantially parallel to said at least one beam.

7. The apparatus of claim 1, wherein said radiation reflecting body includes a cylinder having an axis coinciding with said predetermined axis and a peripheral surface including said at least one surface.

8. The apparatus of claim 1, wherein said body has an external surface and said at least one surface is inclined relative to said external surface.

9. The apparatus of claim 1, wherein said at least one surface includes a plurality of discrete curved sections.

10. The apparatus of claim 9, wherein said body includes partitions intermediate said sections.

11. The apparatus of claim 10, wherein each of said partitions includes one of (a) a step and (b) an uneven part of said body.

12. The apparatus of claim 10, wherein each of said sections includes first and second end portions respectively disposed in discrete first and second planes at least substantially parallel to each other.

13. The apparatus of claim 12, wherein said planes are at least substantially normal to said predetermined axis.

14. The apparatus of claim 12, wherein said first and second planes of the first and second end portions of each of said sections are spaced apart from each other.

15. The apparatus of claim 12, wherein said body has a peripheral surface and said sections are at least substantially uniformly distributed at said peripheral surface.

16. The apparatus of claim 9, wherein said sections are at least substantially identical with each other regarding at least one of their (a) shapes, (b) directions and (c) leads.

17. The apparatus of claim 1, wherein said section of said at least one surface is a helix having with respect to said axis a lead of at least close to 45°.

18. The apparatus of claim 1, wherein said source includes at least one laser.

19. The apparatus of claim 18, wherein said laser is arranged to emit at least one pulsed beam of corpuscular radiation.

20. The apparatus of claim 1, wherein said source and said radiation-reflecting body are installed in a machine for making rod-shaped smokers' products.