WEB CUTTING APPARATUS

Abstract: Transverse cuts are made in a web using a cutter/anvil combination which is subjected to high frequency vibration, preferably ultrasound. In one arrangement, particularly for cutting tea bag webs, a rotary cutter drum (4) cooperates with an ultrasonically-vibrated anvil (12). The web may be simultaneously sealed and cut by means of a modified drum (202) having sealer/cutter elements (208, 210). In other arrangements, particularly for cutting cork paper on a machine for assembling filter cigarettes, the paper is severed on a drum (106, 122, 192, 350) cooperating with an ultrasonically-vibrated anvil (110, 194, 312) or directly on an ultrasonically-vibrated drum (144, 160, 170, 180).

Description: l Web Cutting Apparatus 2 3 This invention relates to web cutting apparatus, particularly but not exclusively as employed for severing webs in packaging or wrapping 5 processes. 6 According to one aspect of the invention apparatus for making 7 successive longitudinally spaced cuts in a web comprises means for s moving the web, means for periodically bringing a cutter into the region 9 of the web, and means for producing high frequency relative vibration ιo between the cutter and the web, so that the cutter makes at least one π cut, having at least a portion extending in a transverse direction of the i2 web. The vibration may have a primary amplitude transverse to the web, i3 either in its thickness direction or across its width, or its primary direction I-. may be longitudinal relative to the web. Preferably the cutter cooperates is with an anvil (which term is used herein to include any counter surface) 16 and the vibration producing means produces relative vibration between i7 the cutter and the anvil. Preferably the vibration producing means is comprises an ultrasound generator. In a preferred arrangement the anvil i is subjected to ultrasound vibration, although the cutter itself may be 2 o vibrated, either in a direction across the web width (i.e. in a sawing 2i action) or in a direction parallel to the thickness of the web (in a 2 2 crush-cut action). 23 The cutter is preferably moved with the web, (e.g. by being 2-. mounted on a roller), although it need not move at the same speed as 25 the web. The anvil may be stationary (apart from the generated 2 6 vibration) or may move with the web or the cutter, although again not 2 7 necessarily at the same speed. The device may be arranged to sever 2 8 portions of the web from the remainder of the web, e.g. by severing 2 9 successive leading portions. Where the anvil is a movable member, e.g. • so a rotary drum, sections severed from the web may be subsequently 3i conveyed on the anvil. Alternatively, where the cutter is mounted on a 3 2 movable member the severed sections could be subsequently conveyed 3 on the member. 3* in one application the invention is embodied in a machine for 5 producing packages containing tea or other infusible material. Thus, a 6 double ply web containing spaced portions of infusible material may be 7 subjected to cutting by a device according to the invention in which the 8 cutter has a cutting edge which surrounds the portion of infusible ι material and cuts it out from the web. The cutting edge may thus define 2 the shape of the package containing infusible material produced from 3 the web. It will be understood that the edges of any such package have * to be sealed to prevent the infusible material escaping. Sealing may be 5 carried out by rollers or other suitable means arranged upstream of the 6 cutting device and synchronised with it so that the web is cut in a region 7 such that the cut edge or edges of the packet are separated from the a infusible material by a sealed portion of web. As an alternative to providing such separate sealing means, and in ιo accordance with another aspect of the invention, a cutting device (which ιι may be, but is not necessarily, constructed in accordance with said one i2 aspect of the invention) comprises means for performing a sealing i3 operation on an adjacent portion of the web substantially simultaneously i4 with the cutting operation. In this case, the device preferably performs i sealing and cutting with the assistance of ultrasound. A suitable cutting i6 and sealing element, which could be carried by a rotary drum for i7 cooperation with a stationary ultrasonically-vibrated anvil comprises a is relatively flat portion for sealing and a relatively narrow edge portion e.g. i9 abutting the flat portion, for cutting. Preferably the sealing portion is 20 arranged to contact a downstream portion of the web relative to the 2i cutting edge. Where sealing and cutting are carried out in separate 22 processes with the sealing operation performed on the web upstream of 23 the cutting operation, in order to provide adequate tolerance for 2 registration at the cutting operation the sealing width may need to be 25 wider than strictly necessary to provide an adequate seal. By combining 26 the cutting and sealing operations, problems of registration are avoided 27 and there is a potential materials saving by reducing the width of the 28 seal. 29 It is preferable to control the relative spacing between a cutter and 30 anvil for effective cutting of a web of predetermined thickness, in a 3i device for cutting a two ply web of heat-sealable filter paper for making 32 tea bags, having a thickness of web to be cut of about 0.075mm, a mean 33 spacing between a rotary cutter having a diameter of about 135mm and 34 a stationary anvil of about 0.04mm has been found to be effective using 35 an ultrasonic generator which produced ultrasound vibrations in the anvil 36 having an amplitude (peak to peak) of about 0.07 - 0.08mm in a direction 7 transverse to the web. A preferred frequency for the ultrasound vibration 8 is 20kHz. Higher frequencies (e.g. 40kHz) are usable and may be UBSTITUTE SHEET 1 desirable for very high speed operation but maintaining adequate 2 amplitude of vibrations at higher frequencies uses more power. 3 Frequencies lower than 20kHz (i.e. below those normally recognised as ultrasound) may be used, but particularly with high speed machinery the 5 advantages gained by providing vibration at lower frequencies, as 6 compared with providing no vibration, may be marginal. With the 7 arrangement described above, with a web speed of about 1.2 β metres/second, the web is subjected to 30-40 cycles of ultrasonic vibration while the knife is in contact with it. ιo Means may be provided for adjusting the spacing between an ιι anvil and a cutter, preferably by sensing the distance between the anvil i2 and cutter (or parts movable with them) and by moving the anvil in i response to the sensed distance. In practice it may be difficult to obtain i4 measurements directly from a member which is subject to vibration; the is adjusting means may therefore include control means (which may i6 include software) for adjusting the spacing according to parameters i7 which relate indirectly to the spacing. Thus, adjustment could be made is according to a mapped position profile against time after start up to i compensate for thermal expansion, or against a number of cuts made to 20 compensate for wear in the cutter and/or anvil. 2i The spacing between the anvil and the cutter may be set by 22 spacing means. In a preferred arrangement wherein the cutter is carried 23 on a rotary drum, the spacer means comprises one or more control rings 2 carried by the drum and arranged so that their circumference is at a 25 radius from the axis of the drum which bears a predetermined 26 relationship to the radius at which the cutting edge of the knife is carried. 27 The rings could have the same radius as that of the cutting edge of the 28 knife, so that the control rings maintain the anvil at a distance from the 29 general surface of the knife drum which is equal to the radial distance by 0 which the knives project from that surface. The anvil, which may be i stationary or could comprise a further drum, and the knife carrying drum 2 may be resiliently urged together, with the control rings setting the 3 spacing between the anvil and the drum, and hence between the anvil and the knives. 5 In another application of cutting apparatus according to the 6 invention, the apparatus is employed in a machine for assembling filter 7 cigarettes, for cutting the filter tipping paper (so called "cork" paper) 8 which is wrapped around axially aligned assemblies of filter and tobacco SUBSTITUTE SHEET 1 rods to produce filter cigarette assemblies. 2 In one preferred arrangement a web of filter tipping paper is 3 delivered at a controlled speed to a suction and cutting drum which is 4 rotating at a faster speed than the web, the drum carrying knives which 5 cooperate with a vibrating anvil to sever successive leading sections of 6 the filter paper. These sections are subsequently conveyed on the drum 7 towards a rolling plate at which they are wrapped and united around the β filter and tobacco rods. A similar arrangement is usable to unite other 9 rod-like articles of the tobacco industry. ιo Adhesive may be applied to the web upstream of the drum, to ιι either face of the web. Where the adhesive is on the face of the web i2 which contacts the anvil the latter will probably require cleaning means i3 to remove adhesive which is transferred to it from the web. Where the i4 adhesive is applied to the surface of the web which contacts the suction is and cutting drum, the adhesive is preferably applied to the web in a i6 pattern which leaves regions with no adhesive, the suction ports on the i7 drum being arranged to coincide with these regions so as to minimise is transfer of adhesive to the drum. Cleaning means, such as a brush i and/or suction, may be provided for the drum. Where the wrapper 20 sections are carried on the drum with the adhesive outermost the 2i sections may be supplied directly to the region of a rolling plate for 22 uniting the filter cigarette assemblies. In order to prevent damage 2 3 occurring to the assemblies at the rolling plate from the protruding 2 4 knives of the drum the knives may be arranged to be retractable, e.g. by 2 5 mounting them on radial slides operated by a central cam. 26 Instead of applying adhesive to the web the adhesive could be 27 applied to the sections after cutting: this would have the advantage of 28 eliminating the need to clean the anvil but would involve a more 29 complicated adhesive applying means which is capable of applying 30 adhesive to spaced sections on the drum. 3i Instead of using a stationary anvil a rotary ultrasonically vibrated 32 anvil may be used. The vibrations set up in the anvil may, according to 33 its design, be radial or circumferential. In either case the anvil preferably 3 cooperates with a drum carrying the or each cutter. Severed wrapper 35 sections may be conveyed away on the rotary anvil or on the cutter 36 drum. Where a rotary anvil is employed a central or core ultrasound 37 generator may cooperate with a number of generally radial spokes 38 forming ultrasound boosters the ends of which form the anvil surfaces SUBSTITUTE SHEET 1 against which the cutter or cutters operate. Conveniently this form of 2 rotary anvil may comprise a drum with the end faces of the spokes flush 3 with the general circumference of the drum. 4 The invention will be further described, by way of example only, 5 with reference to the accompanying diagrammatic drawings, in which: 6 Figure 1 is a part-sectional view of a web cutting device taken 7 along a line transverse to the web, s Figure 2 is a part-sectional view of the device of Figure 1 taken 9 along a line parallel to the web, ιo Figure 3 is a view, similar to that of Figure 1 , of a modified web a cutting device, i2 Figure 4 is a view, similar to that of Figure 2, of the device of i3 Figure 3, i Figure 5 is a view on the line V-V in Figure 4, is Figure 6 is a side view of another web cutting device, i6 Figure 7 is a side view of a further web cutting device, i7 Figure 8 is plan view of a web in the device of Figure 7, showing is the gummed areas of the web, i9 Figure 9 is a side view of a further web cutting device, 20 Figure 10 is a side view of a modified roller for use with the device 2i of Figure 9, 22 Figure 11 is a side view of a further web cutting device, 23 Figure 12 is a side view of a still further web cutting device, 24 Figure 13 is a transverse sectional view of a modification of the 25 web cutting device of Figure 7, 26 Figure 14 is a side view of part of a web cutting and sealing 27 device, ∑β Figure 15 is a part-sectional view of a modified roller for use in a 29 web cutting device, 30 Figure 16 is a view, similar to that of Figure 1 , of a further modified 3i web cutting device, and 32 Figure 17 is a view, similar to that of Figure 2, of the device of 33 Figure 16. 3 Figures 1 and 2 show a web cutting device for use in a machine 35 for cutting out round bags from a two-ply web 2 having spaced portions 36 containing tea or other infusible material. The general construction and 37 operation of the machine forms no part of this invention but reference is 38 directed to PCT patent specification No. WO 90/13487 for details of a SUBSTITUTE SHEET 1 machine with which the device is usable. 2 The web 2 is conveyed beneath a cutting roller 4 which is 3 provided with recesses 6 surrounded by raised cutting edges 8. The 4 web 2 is maintained under tension and conveyed past the roller 4 by nip s rolls 10 which are synchronised with the roller so that the speed of the 6 web and the peripheral speed of the roller are matched. The roller 4 is 7 synchronised with means (not shown) for sealing the two plies of the s web 2 together in a peripheral region around each portion containing 9 infusible material, so that these portions coincide with the recesses 6 at ιo the roller 4 and the peripheral regions coincide with the cutting edges 8. ιι An anvil 12 is situated beneath the roller 4 and has an upper face i2 which is spaced closely to the periphery of the roller and which provides i3 a surface against which the cutting edges 8 operate. The anvil 12 forms i4 part of an ultrasonic device 14, which also comprises an ultrasonic is generator 16 containing piezoelectric material and a part 18 comprising a i6 booster for amplifying the ultrasound generated by the generator and for i7 transmitting it to the ultrasonic horn or anvil 12. A commercially available is device suitable for performing the function of the device 14 is Model i9 902R available from Branson Ultrasound of Hayes, Middlesex, England. 2o The anvil 12 is constructed of a mechanically-suitable material capable of 2i withstanding the ultrasound vibrations without suffering from fatigue. 22 Typically the material may be suitable alloys of titanium (e.g. AI6Va4) or 23 aluminium (e.g. He15). Depending on its dimensions the anvil 12 may 24 have one or more longitudinal slots (not shown) extending parallel to its 25 axis: such slots may be required where the width of the anvil is more 2 6 than about two thirds of its length. The booster 18 could be incorporated 27 within the anvil 12: this has the advantage of making the device 14 28 shorter. 29 The ultrasound generator 16 is rigidly connected to the lower face 30 of a housing 20. The part 18 is connected to an internal flange 22 in the 3i housing 20, its mounting position being at a node relative to the primary 2 frequency of the ultrasound generated by the device, so that there is little 33 or no relative vibration transmitted to the housing. The anvil 12 has 3 integral side pieces 24 each connected to the main central part of the 35 anvil by upper and lower thin strips or beams 26. The side pieces 24 are 36 connected to a lower plate 28 which is itself connected to the housing 37 20. The beams 26, which may for example be of 1 mm thickness, allow 38 the anvil 12 to perform ultrasound vibrations transmitted to it from the SUBSTITUTE SHEET 1 booster part 18 without transmitting substantial vibrations to the side 2 pieces 24 and hence to other parts of the machine. In other words the 3 beams 26 effectively isolate the anvil 12 dynamically from the remainder 4 of the machine. 5 The side pieces 24 have outer vertically-extending extensions 25 6 which are constrained by and vertically slidable in guideways 30 provided at each side in a structural part 32 of the machine. Each side β piece extension 25 has an extending pin 34 which is engaged by a 9 movable element of a linear actuator 36 connected to the part 32. ιo At their upper faces the side pieces 24 carry gap transducers 40 ιι for sensing the distance between the anvil 12 and the roller 4. The i2 transducers 40 may be optical or eddy current transducers. Any i3 deviation from a desired distance may be corrected by operation of the i4 linear actuators 36 to reposition the device 14 relative to the roller 4. is After adjustment, the device 14 can be locked in position by clamping i6 the side piece extensions 25 in the guideways 30 by means of i7 pneumatic clamps 38 (Figure 2). The linear actuators 36 may include is rotary encoders by means of which the position of each actuator relating i to a datum setting may by determined. 20 In operation, with a web 2 having a nominal thickness of 2i 0.075mm, the anvil 12 is placed typically at a mean spacing of 22 0.03-0.04mm from the path of the cutters 8. The amplitude of the 23 ultrasonic vibration is typically 0.07-0.08mm at a frequency of 20kHz. At 24 a web speed of 1.2 metres/second it is believed that the web is trapped 25 and released some 30-40 times per pass of each portion of cutting edge 26 8. As compared with operating a cutting roller 4 in conjunction with an 27 anvil or counter-surface not subject to high frequency vibration the 28 device significantly prolongs useful life of the cutting edges 8, 29 particularly by providing an acceptable cut even when the cutting edge 30 is relatively blunt, while the vibration is believed to facilitate relatively 3i smooth passage of the web between the roller 4 and anvil 12. 32 The effectiveness of the cutting operation is dependent on 3 relatively accurate positioning of the anvil 12. The linear actuators 36 4 may comprise linear ball screws with high ratio gear boxes to provide 5 location of the anvil 12 which is accurate to within a few microns. The 6 actuators are independently adjustable, depending on signals from the 7 position transducers 40, so as to be capable of adjustment to maintain 8 the anvil parallel to the roller 4. The face of the anvil 12 which SUBSTITUTE SHEET 1 cooperates with the cutting edges 8 is subject to wear, typically at a rate 2 of about 1 micron every 150,000 cuts. A higher wear rate may be 3 tolerated, particularly where it is desired to reduce the wear rate of the 4 cutting edges 8: in such case the anvil 12 may be constructed of a 5 material which is softer than titanium, e.g. aluminium. Because of their 6 location, the position transducers 40 do not detect wear: however, the 7 control circuit linking them to the actuators 36 may include means (e.g. s embodied in software) for compensating for wear (e.g. by modifying the 9 measured distance according to the number of cuts made since a datum ιo setting of the relative positions of the transducers and the surface of the a anvil 12). Similarly, the actuators may need to be controlled according to i2 a mapped movement profile during start-up to compensate for changes i3 in relative position due to thermal expansion as the device is run up to i4 operating temperature: reaching a stable operating temperature from is rest may take up to 20 minutes. A typical running temperature for the i6 anvil 12 is 70°C. Effects of thermal expansion can be reduced by i7 reducing the distance between the pins 34 (on which the position is actuators 36 operate) and the working face of the anvil 12. i9 The device shown in Figures 3-5 is similar to that of Figures 1 and 2o 2, and similar parts have been given similar reference numbers. The 2i main difference between the devices lies in the mounting of the anvil 12. 22 In the device of Figures 3-5 a rectangular housing 50 is connected to the 23 upper surface of the housing 20 and surrounds the lower half of the anvil 24 12. At its upper end the housing 50 has a slot 52 through which projects 25 the upper part of the anvil 12. Mounting flanges 54 are provided on the 26 anvil 12 and these are connected to the housing 50 on opposite sides of 27 the undersurface of the slot 52. The flanges 54 are positioned at a node 28 in the ultrasound vibration generated in the anvil 12, so that minimum 29 vibration is transmitted to the housing 50. At each side the housing 50 30 has rectangular extensions 56 which engage in and are slidable in the 3i guideways 30. The housing 50 also has upward extensions 58 at each 32 side of its upper face, these carrying the position transducers 40. 3 Operation of the of device of Figures 3-5 is analogous to that of the 34 device of Figures 1 and 2. 5 The web cutting devices depicted in Figures 6-13 are applicable 6 to cutting filter tipping paper (commonly known as "cork" paper) in a filter 37 cigarette assembling machine. In this type of machine it is 8 commonplace to feed a web of gummed cork paper at a controlled E 1 speed onto a suction drum which is continuously rotating at a faster 2 peripheral speed than the speed of the web. The cork web is 3 transversely cut while on the drum to provide spaced sections which are 4 subsequently conveyed at the speed of the drum. Cutting is usually 5 achieved by means of knives mounted on a separate roller which 6 cooperates with the suction drum. The severed cork sections travel with 7 the drum to a position at which they are picked up by and subsequently β rolled around axially aligned filter and tobacco portions to unite them into 9 a filter cigarette assembly. For further details of a filter cigarette ιo assembling machine of this type reference is directed to British patent ιι specification No. 941832. i2 In the device of Figure 6 a web 100 of filter tipping paper is fed at i3 a controlled speed by nip rolls 102 past a gumming roller 104 which i applies adhesive (possibly in a predetermined pattern) to the paper. For is convenience the adhesive will hereinafter be referred to as "gum", i6 although it will be appreciated that not all suitable adhesives are true i7 gums. The web 100 passes to a suction cutting drum 106 provided with is knives 108 which cooperate with an ultrasonically-vibrated anvil 110 to i sever the web into wrapper sections subsequently conveyed on the 20 drum. Filter cigarette assemblies to be united are delivered by a fluted 2i drum 112 and are brought together with the wrapping sections on a 2 2 rolling plate 114 at which the sections are wrapped and sealed around 23 the assemblies. The united assemblies are subsequently conveyed 24 away by a further fluted drum 116. 25 The anvil 110 may be substantially similar to the anvil 12 in the 26 devices of Figures 1 and 2 or Figures 3-5, and be incorporated in a 27 device similar to the device 14. The anvil 110 needs continuous 28 cleaning in the region 118 as it will tend to collect some gum from the 29 web 100 in this region. Cleaning can be achieved by a rotary brush 0 and/or suction collection of excess gum on the anvil 110. 3i The knives 108 typically project about 0.2mm above the general 32 surface of the drum 106. In order to protect the filter cigarette 3 assemblies at the rolling plate 114 the knives 108 may be mounted in 4 radial slides and actuated by a cam 120 so that they are extended in the 5 region of the anvil 110 but retracted to a position at or below the level of 6 the drum 106 at the rolling plate. 7 Instead of using gummer 104 to apply adhesive to the web 100 8 upstream of the anvil 110, with attendant cleaning problems, a gummer 1 104A could be used for applying adhesive to the severed sections of the 2 web. The gummer 104A is synchronised with the passage of wrapper sections on the drum 106, so that adhesive is applied to the sections and not to the drum. Depending on the characteristics of the adhesive, a 5 heater and/or dryer 105 may be required, in view of the closeness of the 6 gummer 104A to the rolling plate 114. 7 In the device of Figure 7 parts similar to those in the device of β Figure 6 have been given similar reference numbers. The web 100 is 9 gummed by a gummer 104 acting on its undersurface and is delivered to ιo a suction rolling drum 122 which is provided with fixed knives 124. As a shown in Figure 8, the pattern of gum 126 applied to the web 100 i2 includes windows 128 of ungummed paper. By arranging for suction i3 ports on the drum 122 to apply suction only at positions corresponding i4 to the windows 128, transfer of excessive amounts of gum to the surface is of the drum can be avoided. A rotary brush 130 removes gum which i6 remains on the knives 124 and any small amounts deposited on the i7 surface of the drum 122. The wrapper sections severed from the web is 100 are carried by the drum 122 and transferred to a further suction i9 drum 134 from where they are wrapped around assemblies to be united 2o delivered to the rolling plate 114. Note that in this arrangement gum 2i does not collect on the anvil 110. As a supplement or alternative to the 22 rotary brush 130 a pivoted scraper blade 131 could be used. This could 23 be cam-operated so as to be lifted to avoid the knives 124. Alternatively 24 a wheel with flexible blades, i.e. a flap wheel, could be used. 25 In an alternative way of operating the embodiment of Figure 7 the 26 gummer 104 is omitted and the web 100 is precoated with an adhesive 27 (e.g. hot melt or PVA) which is substantially dry by the time the web 2 8 contacts the drum 122 and which is reactivated by a heater 133 on the 2 9 drum 134. The brush 130 should not then be necessary. 30 Figure 9 shows a web cutting device employing an 3i ultrasonically-vibrated rotating cylinder 140 comprising an annular 32 piezoelectric core 142 surrounded by a titanium alloy sleeve 144 which 33 acts as a booster for the ultrasonic vibrations. The cylinder 142 34 oscillates in a circumferential oscillation mode (as opposed to a radial or 35 wall thickness changing mode). Cooling fluid is passed through the 36 centre of the core 142. 7 A web 100 is delivered at a controlled speed by nip rolls 102 and 8 receives gum from a gummer 104. A suction cutting drum 146 provided SUBSTITUTE SHEET 1 with spaced cutting knives 148 is opposed to the cylinder 140 and 2 cooperates with it to produce cut wrapper sections which are conveyed 3 away by the drum 146 to a rolling plate (not shown). The surface of the 4 titanium alloy sleeve 144 is hardened to resist damage from the knives 5 148. The drum 146 and knives 148 may be similar to the drum 106 and 6 knives 108 of the device shown in Figure 6. 7 The cylinder 140 may be provided with suction instead of the a drum 146 so that the cut wrapper sections are conveyed away by the 9 cylinder. In this case the uniting of the wrapper sections and filter ιo cigarette assemblies may take place at a rolling plate 150 cooperating ιι directly with the cylinder 140 or at a rolling plate 152 cooperating with a i2 further suction drum 154 which receives wrapper sections from the i3 cylinder. In this last case the gummer 104 is replaced by a gummer i4 104A acting on the undersurface of the web 100. The suction regions of is the cylinder 140 may be arranged to coincide with areas of ungummed i6 web, as explained with reference to Figures 7 and 8. As compared with i7 the previous embodiments the Figure 9 arrangement has the advantage is that the ultrasound device 140 is movable with the web 100. i9 Figure 10 is a side view of a modified cylinder 160, which may 20 replace the cylinder 140 in the device of Figure 9. The cylinder 160 2i consists of a titanium alloy ultrasonic horn formed with an integral 22 subshaft 162 which is attached to an ultrasonic generator and booster 2 3 (not shown). The generator and booster rotate at the speed of the ∑4 cylinder 160, with slip ring electrical contacts and air supply (for suction 2 5 on the surface of the cylinder and also for air cooling). The cylinder 160 26 is designed such that ultrasound vibrations generated along the axis of 27 the cylinder are converted into vibrations perpendicular to this axis, i.e. 28 radial vibrations. This transverse vibration may be supplemented by 29 cantilever mounting of the cylinder 160 so that it has a resonant 30 frequency within the range of the frequency of the ultrasonic vibration. 3i Alternatively, the cylinder 160 may have a coaxial support shaft 161. The 32 form of the cylinder 160 could be similar to the ultrasonic transducer 33 disclosed in British patent specification No. 1524924, to which reference 34 is directed for details. 35 In the embodiment of Figures 9 and 10 the cylinders 140 and 160 36 need not be the anvils: they could carry the cutting knives. 37 In the device shown in Figure 11 a web 100 is delivered to a 38 suction cylinder 170 having two cutting stations defined by the end faces SUBSTITUTE SHEET 1 of two ultrasonic boosters 172 which are connected to a central common 2 ultrasonic generator 174 which causes the faces of the boosters to 3 vibrate in a radial direction relative to the cylinder 170. A knife cylinder 176 having one or more knives 178 cooperates with the cylinder 170 so 5 that the web 100 is cut when a knife is opposed to an end face of one of 6 the boosters 172. The wrapper sections severed from the web 100 are 7 conveyed by the cylinder 170 to a rolling plate 150. Alternatively, the β web 100 is gummed on its undersurface by a gummer 104A and the 9 severed wrapper sections are transferred to a further suction drum 154 ιo for uniting filter assemblies at a rolling plate 152. The wrapper sections ιι could be conveyed by a modified cylinder 176 (provided with suction) i2 instead of by the cylinder 170, i.e. in a way similar to that described with i3 reference to Figure 9. i4 The device of Figure 12 is similar to that of Figure 11 except that is the cylinder 170 is replaced by a modified ultrasonic cylinder 180, which i6 comprises a central piezoelectric tubular core 182 forming part of an i7 ultrasonic generator, and a series of radial titanium spokes 184 forming is ultrasonic boosters and having their radially outermost faces hardened i9 and substantially flush with the general surface of the cylinder so as to 2o form anvils against which the knives 178 operate. Cut wrapper sections 2i may be conveyed to a roiling plate 152 by way of a further suction drum 22 154, or directly to a rolling plate 150 if the web is gummed by an upper 2 3 gummer 104A. In this latter case a brush 186 is provided to remove 24 excess gum from the knife drum 176 and knives 178. 25 Figure 13 shows a sectional view of a knife drum 190 having 26 knives 192 cooperating with a stationary ultrasonic anvil 194. Thus the 27 drum 190 and anvil 194 may be similar to and replace the drum 122 and 28 anvil 110 in the device of Figure 7, for example. Alongside the drum 190 29 are laterally spaced control rings 196, which are ground to the same or 30 similar diameter as that of the drum 190 measured at the outer edges of 3i the knives 192 and act as a stop for the anvil 194 at times when a cut is 32 not being made. The anvil 194 could be resiliently preloaded against the 33 control rings 196: this can avoid having to make adjustments to 34 compensate for thermal expansion of the anvil during the period 5 following start up. 36 Control rings similar to the rings 196 could be used with a rotary 7 ultrasonic anvil, e.g. any of the cylinders 144, 160, 170, and 180, shown 8 in Figures 9-12. SUBSTITUTE SHEET ι Figure 14, which is not to scale, is an enlarged side view of a 2 modified web cutting device capable of sealing and cutting substantially 3 simultaneously. The device is particularly usefully applied in the 4 apparatus of Figures 1 and 2 or Figures 3-5, where usually the double 5 ply web 2 is sealed by separate web sealing rollers upstream of the 6 cutting rollers 4. Use of the device shown in Figure 14 avoids the need 7 for separate sealing rollers. β A web 200, which may comprise a double ply web containing 9 spaced regions of infusible material, is advanced between a cutting and ιo sealing roller 202 and a stationary ultrasound anvil 204. The roller 202 a carries cutting and sealing elements 206 which define the shape of the i2 portion of web to be sealed and cut out. Thus the elements 206 may i3 define an enclosed region, e.g. having a circular periphery similar to the i4 edges 8 in the Figure 1 device, or could extend transversely so that only is transverse cuts and seals (e.g. severing the web) are made by the i6 elements 206. In this instance one or more longitudinal seals in the web i7 to complete the enclosure of each portion to be cut out may be made by is other means (not shown), preferably upstream of the roller 202. i The elements 206 comprises a narrow cutting edge 208 having a 20 width of about 0.1 mm and a relatively wide shoulder 210 having a width 2i of about 4mm. The edge 208 projects about 0.05mm above the 2 2 shoulder 210 and the latter projects about 0.02mm above the general 2 circumference of the roller 202. The pressure and heat generated 24 between the shoulder 210 of the element 206 and the ultrasonic anvil 25 204 causes sealing of the double ply web 200, which for this purpose 26 may be formed from thermally weidable material or may be preprinted at 27 appropriate positions with an adhesive which is susceptible to activation 28 or setting by application of heat. The edge 208 provides a localised 29 increased action against the web 200 and anvil 204, sufficient to sever 30 the web. The shoulder 210 need not be flat, and could have a convex i surface for effecting sealing of the webs. 2 Figure 15 shows part of a modified roller 220, which may replace 3 any of the rollers 144, 160, 170 or 180 in the previously-described 4 embodiments. The roller 220 includes anvils 222 formed at end faces of 5 an ultrasonic beam 226 which is cantilevered from an integral central 6 upstanding strut 228. A piezoelectric stack, forming an ultrasonic 7 generator 230, is arranged between one arm of the beam 226 and an 8 integral base 232. The amplitude of the vibrations at the generator 230 is 1 effectively amplified at the anvils 222 by flexing of the beam 226 about its 2 connection to the strut 228. The roller 220 has additional similar anvils 3 222 (not shown) arranged symmetrically around its circumference. An 4 additional piezoelectric stack could be provided on the opposite side of 5 the strut 228, to balance the stack forming the generator 230. 6 The device shown in Figures 16 and 17 has many similarities with 7 the devices of Figures 1 and 2 and Figures 3-5. The device includes an s ultrasound generator 316 mounted in a housing 320 and connected to a horn or anvil 312 which is clamped to the housing at a nodal flange 322. ιo The lower end of the anvil 312 is located just above the surface of a ιι suction drum 350 which carries spaced knives 352 for severing i2 successive leading sections from a web 100, the drum including suction i3 holes 354 for retaining the severed web sections on the drum after i cutting. Close to the upstream edge of the lower end of the anvil 312 is is an air nozzle 356 including a slit 358 from which an air jet is directable at i6 the region of the surface of the drum 350 just upstream of and adjacent i7 the anvil. The slit 358 extends for at least the width of the web 100, and is preferably for the width of the anvil 312. An air jet issuing from the slit i9 358 has been found beneficial in locating the web on the surface of the 20 drum 350 just prior to severing between the knives 352 and the anvil. 2i The web 100 is gummed on its upper surface at a position 22 upstream of the drum 350, the web passing over a heating and/or drying 23 element 360. Providing a bevelled or chamfered surface on the 24 upstream lower edge of the anvil 312 reduces problems associated with 25 build up of gum on the anvil. Where such a bevelled or chamfered 26 upstream edge is provided for the anvil 312 it is preferred to provide a 2 similarly-shaped downstream edge. The effect of the air jet issuing from 28 the slit 358 in maintaining the web on the drum 350 is also believed to be 29 beneficial in reducing problems with build up of gum on the anvil. 30 A simple web speed modulator 362 is shown in Figure 17. This 3i comprises an element which is rotatable or reciprocable periodically and 32 is synchronised with the drum 350 to deflect the web and so modulate 33 the path of the web 100 so that it travels at the same speed as the drum 34 at the instant when a knife 354 is passing the anvil 312 but at a lower 35 speed at other times. 36 The housing 320 is slidable in guideways 330 in an adjuster frame 7 370. The position of the housing 320, and hence of the anvil 312, 8 relative to the frame 370 is controlled by microadjusters or linear SUBSTITUTE SHEET 1 actuators 336. The frame 370 carries cam rollers 372 which bear on 2 annular hardened circumferential inserts 374 carried by the drum 350. 3 Load cylinders 376 are arranged between a machine frame part 378 and the housing 320, the arrangement being such that the cylinders apply a 5 predetermined load through the housing and the frame 370 to the rollers 6 372. The microadjusters 336 thus effectively set the gap between the 7 surface of the drum 350 (or more correctly the locus of the knives 352) β and the lower edge of the anvil 312. 9 A device similar to that disclosed in Figures 15 and 16 may be ιo used in the embodiments of Figures 6 or 7, or to replace the device of ιι Figures 1 and 2 or Figures 3-5 in any of the previously-described i2 embodiments. i3 Although specific mention has been made of ultrasound i4 generators including piezoelectric material the ultrasound could be is generated in any convenient manner and using any suitable material. i6 For example magnetostrictive material could be used: this may have i7 advantages as it can be structurally stronger than piezoelectic material. 18 19 20 21 22 2 3 2 4 2 5 26 7 8 9 0 1 2 3 4 5 6 7 8 SUBSTITUTE SHEET

Claims: 1 Claims 2 3 1. Apparatus for making successive longitudinally-spaced 4 cuts in a web comprising means for moving the web, means for 5 periodically bringing a cutter into the region of the web, and means for 6 producing high frequency relative vibration between the cutter and the 7 web, so that the cutter makes at least one cut having at least a portion s extending in a transverse direction of the web. 9 lo 2. Apparatus as claimed in claim 1 , wherein the vibration ιι producing means comprises an ultrasound generator. 12 i3 3. Apparatus as claimed in claim 1 or claim 2, wherein the i4 primary amplitude of the vibration is transverse to the web. 15 i6 4. Apparatus as claimed in any preceding claim, wherein the i7 cutter cooperates with an anvil in a cutting region and the vibration is producing means produces relative vibration between the cutter and the i9 anvil. 20 2i 5. Apparatus as claimed in claim 4, wherein the path of the 22 web extends between the cutter and the anvil and at least one of the 23 cutter and anvil is movable with the web. 24 25 6. Apparatus as claimed in claim 4 or claim 5, wherein the 26 cutter is carried by a rotary member which serves to convey sections of 27 the web which have been cut to a position downstream of the cutting 28 region. 29 30 7. Apparatus as claimed in any of claims 4 to 6, wherein the 3i vibration producing means comprises an ultrasound generator linked to 32 the anvil. 33 34 8. Apparatus as claimed in claim 7, wherein the anvil includes 35 an end surface for cooperating with said cutter, said surface extending 36 for the width of the web and having a relatively narrow dimension in the 37 direction of movement of the web. 38 SUBSTITUTE SHEET 1 9. Apparatus as claimed in claim 8, wherein said surface is 2 bevelled at least along its edge which is upstream relative to the direction 3 of movement of the web. 4 5 10. Apparatus as claimed in any of claims 4 to 9, including 6 means for mounting the anvil so that it may be moved towards or away 7 from the cutter so as to adjust the spacing between the anvil and the s cutter. 9 lo 11. Apparatus as claimed in claim 10, wherein the position of π the anvil relative to the cutter is determined by at least one linearly i2 movable adjustment means. 13 i 12. Apparatus as claimed in claim 10 or claim 11 , wherein the is spacing between the anvil and cutter is determined by rotary means i6 acting between the anvil and means carrying the cutter. 17 is 13. Apparatus as claimed in claim 12, wherein the cutter is i9 carried on a rotary drum, including a first frame member carrying the 20 anvil, a second frame member carrying roller means contacting said 2i drum, and means for adjustably mounting said first frame member 22 relative to said second frame member. 23 24 14. Apparatus as claimed in claim 7, wherein the anvil 25 comprises a rotary member and the ultrasound generator is arranged to 26 produce vibrations which are radial relative to said member. 27 28 15. Apparatus as claimed in any of claims 4 to 6, wherein the 29 vibration producing means comprises an ultrasound generator linked to 30 the cutter. 31 32 16. Apparatus as claimed in claim 15, wherein the cutter is 33 carried by a rotary member and the ultrasound generator is arranged to 34 produce vibrations which are radial relative to said member. 35 6 17. Apparatus as claimed in claim 14 or 16, wherein the 7 ultrasound generator is arranged to produce radial vibrations in an 8 annular peripheral part of said rotary member. SUBSTITUTE SHEET 1 18. Apparatus as claimed in claim 14 or 16, wherein the 2 ultrasound generator is arranged to produce radial vibrations in at least 3 one radially extending member of said rotary member. 4 19. Apparatus as claimed in any of claims 4 to 18, further 6 including means for directing an air jet in the vicinity of said cutting 7 region so as to assist in maintaining said web in a preferred cutting β position in said region. 9 lo 20. Apparatus as claimed in claim 19, wherein said cutter is a carried by a rotary member and said anvil is linked to an ultrasound i2 generator, wherein said air jet directing means is arranged to assist i3 maintaining said web on the surface of said rotary member. 14 is 21. Apparatus as claimed in any of claims 4 to 20, wherein the i6 cutter is arranged to sever successive portions of the web from the i7 remainder of the web. 18 i 22. Apparatus as claimed in claim 21 , wherein the cutter has a 20 cutting edge arranged to sever portions of predetermined shape from 2i the web. 22 23 23. Apparatus as claimed in claim 21 or claim 22, wherein the 24 web comprises at least two layers of material carrying spaced doses of 25 material to be packaged between the layers and said severed portions of 26 the web correspond to individual packages containing said material to 27 be packaged. 28 29 24. Apparatus as claimed in claim 23, including means for 30 sealing the web adjacent at least part of the peripheral margin of the 3i severed portions. 2 3 25. Apparatus as claimed in claim 24, wherein said sealing is 34 performed substantially simultaneously with the severing operation of 5 said cutter. 6 7 26. Apparatus as claimed in claim 25, wherein said sealing and 8 severing operations are carried out with the assistance of ultrasound. ®L- ≥-ST!TUTE S- EΕ1 1 27. Apparatus as claimed in claim 26, including a cutting and 2 sealing element having a first flat part for sealing a margin of a portion of 3 the web to be severed and a narrow edge part abutting said flat part for 4 severing said portion. 5 6 28. Apparatus as claimed in claim 21 , wherein successive 7 leading portions of the web are severed, including a rotary drum carrying s a plurality of said cutters in equally spaced peripheral positions, said 9 drum being provided with suction means for retaining said portions on ιo the drum after severing. 11 i2 29. Apparatus as claimed in claim 28, including means for i3 cleaning said cutters at a position downstream of said cutting region. 14 is 30. Apparatus as claimed in claim 28 or 29, including means i6 for periodically moving said cutters in a direction which is substantially i7 radial relative to said drum, so as to retract the cutter during part of each is revolution of the drum. 19 20 31. Apparatus as claimed in any of claims 28 to 30, further 2i including means for applying adhesive to said portions after they have 22 been severed from the web. 23 24 32. A method of producing packages from superposed layers 25 of web material containing spaced doses of material to be packaged 26 between the said layers, including the step of cutting packages of 27 predetermined shape from the web using a cutting arrangement which is 28 subjected to ultrasound to assist the cutting. 29 0 33. A method as claimed in claim 32, wherein at least part of i the peripheral margin of the package is sealed with the assistance of 2 ultrasound substantially simultaneously with the cutting step. 3 4 34. A method of cutting a web of paper for uniting 5 axially-aligned rod-like articles of the tobacco industry, including the step 6 of separating successive leading portions of the web by means of a 7 cutting arrangement which is subjected to ultrasound to assist the 8 separating. SUBSTITUTE SHEET

Inventors: AINDOW ALAN MICHAEL, BIRD STEPHEN WILLIAM, CLEALL ANDREW JOHN, HADDOW PHILIP, SEAWARD DAVID ROBERT, VERNON GEOFFERY WILLIAM, WILLETT PETER ERNEST, AINDOW, ALAN, MICHAEL, BIRD, STEPHEN, WILLIAM, CLEALL, ANDREW, JOHN, HADDOW, PHILIP, SEAWARD, DAVID, ROBERT, VERNON, GEOFFERY, WILLIAM, WILLETT, PETER, ERNEST
Applicants: AINDOW ALAN MICHAEL, BIRD STEPHEN WILLIAM, CLEALL ANDREW JOHN, HADDOW PHILIP, MOLINS PLC, SEAWARD DAVID ROBERT, VERNON GEOFFERY WILLIAM, WILLETT PETER ERNEST, AINDOW, ALAN, MICHAEL, BIRD, STEPHEN, WILLIAM, CLEALL, ANDREW, JOHN, HADDOW, PHILIP, SEAWARD, DAVID, ROBERT, VERNON, GEOFFERY, WILLIAM, WILLETT, PETER, ERNEST
Application year: 1993
Main classification: B26D7
IPC codes: A24C5, B26D7, B29C65