GB2249935A - Method of and apparatus for uniformizing the distribution of tobacco particles in twin rod making - Google Patents

Abstract

The flow of tobacco particles, which are delivered to the distributor 2 of a multiple cigarette rod making machine by a pneumatic conveyor wherein the particles undergo partial classification, is homogenized before the particles enter a magazine 11 for a wide supply 9 of such particles. A conveyor 13 draws particles from the magazine 11 and cooperates with other parts of the distributor 2 to form a wide carpet which is divided into narrower carpets 16 preparatory to conversion of narrower carpets into discrete streams which are trimmed and draped to form discrete cigarette rods. The homogenizer 39 employs several vibratory conveyors and/or pivotable flaps and/or ducts and/or winnowers and further serves to distribute surplus tobacco which is trimmed off the streams. <IMAGE>

Description

METHOD OF AND APPARATUS FOR UNIFORMIZING THE DISTRIBUTION OF TOBACCO PARTICLES IN TWIN ROD MAKING MACHINES OF THE TOBACCO PROCESSING INDUSTRY The invention relates to a method of and to an apparatus for uniformizing the distribution of tobacco particles in tobacco processing machines, especially in machines which can be used to simultaneously produce several continuous rods for subdivision into cigarettes or other rod-shaped smokers' products.

More particularly, the invention relates to a method of and to an apparatus for converting a layer of tobacco particles into several continuous tobacco streams and for uniformizing or homogenizing the distribution of different tobacco particles (particularly the distribution of shorter and longer tobacco shreds) in the streams. Still more particularly, the invention relates to improvements in methods and apparatus of the te described in commonly owned U.S. Pat. No. 4,889,138 granted December 26, 1989 to Heitmann et al. for "Method of and apparatus for simultaneously making plural tobacco streams".

The patent to Heitmann et al. discloses an apparatus for simultaneously turning out two continuous parallel tobacco streams which are ready to be trimmed, condensed and wrapped into webs of cigarette paper or the like. The patent further discloses several undertakings to homogenize the streams which are being converted into rod-like fillers of tobacco particles.

Homogenization of the streams is important and desirable in order to ensure that the duality of rod-shaped smokers products which are obtained from one of the fillers will match the quality of smokers' products which are obtained from the other filler or fillers. The important parameters of rod-shaped articles of the tobacco processing industry include their weight, density and hardness as well as the degree of uniformity of distribution of different tobacco particles in various portions of the fillers.

For example, if the apparatus is to turn out two continuous cigarette rods, the distribution of shorter and longer tobacco shreds in one of the rods should be the same as in the other rod. This is important to the smoker because a person who is accustomed to a particular brand will readily detect the difference in quality if a first cigarette contains a larger quantity of shorter shreds while another cigarette in the same packet contains a larger quantity of longer shreds. This affects the taste as well as the "feel" of the cigarettes and the rate of combustion of tobacco.

One feature of the invention resides in the provision of a method of converting a layer which has a predetermined width and consists of or contains tobacco particles into two continuous streams, preferably two parallel streams each of which can be transformed into the rod-like filler of a discrete cigarette rod The method comprises the steps of establishing a supply of tobacco particles which has the predetermined width, withdrawing tobacco particles from the supply (such withdrawing step preferably includes removing tobacco particles along the width of the supply), building the layer from the withdrawn tobacco particles, and replenishing the supply of tobacco particles.The replenishing step includes feeding a flow (e.g., a shower) of tobacco particles toward the supply, intercepting at least a portion of the flow, and uniformly spreading the intercepted portion of the flow into and at least substantially the full width of the supply.

The feeding step can include effecting a movement of tobacco particles in a first direction (e.g., under the action of gravity, by resorting to a winnower and/or by using rotary tobacco propelling elements). The intercepting step can include advancing the intercepted portion of the flow along a first path in a second direction substantially transversely of the first direction, and the spreading step can comprise advancing the particles along a third path in a third direction at least substantially counter to the second direction. The spreading step can further comprise showering the particles from the third path into the supply.

As a rule, the two streams contain a surplus of tobacco particles. Such surplus is removed from the streams by trimming devices and is conveved into the second path for readmission into the supply.

The first and second paths are or can be at least substantially horizontal, and at least one of the advancing steps can comprise advancing the particles bv a vibratory conveyor.

The spreading step can include admitting the intercepted particles into crossing paths and advancing the particles into the supply along such crossing paths. The advancing step can comprise directing substantially one half of intercepted particles into one of the crossing paths and directing the remaining particles into another crossing path.

The spreading step can include changing the direction of intercepted particles in dependency on the distribution of intercepted particles Another feature of the invention resides in the provision of an apparatus for forming a layer which contains or consists of tobacco particles and is to be converted into two continuous tobacco streams (preferably a layer which is to be divided into two equal parallel streams). The apparatus comprises a magazine for a supply of tobacco particles (such supply has the predetermined width), means for withdrawing tobacco particles from the supply, means for converting the withdrawn particles into the layer, and means for replenishing the supply of tobacco particles in the magazine.The replenishing means includes means for feeding a flow (e.g., a shower) of tobacco particles toward the magazine, and means for homogenizing at least a portion of the flow and for spreading the homogenized portion of the flow into and at least substantially the width of the supply.

The feeding means preferably comprises means for delivering at least a portion of the flow to the homogenizing means.

The arrangement can be such that the feeding means includes means for delivering the flow in a first direction and the homogenizing means comprises a particle intercepting conveyor having means for advancing at least a portion of the flow along a first path in a second direction extending substantially transversely of the first direction and a spreading conveyor which receives particles from the intercepting conveyor and includes means for advancing the thus received particles along a second path in a third direction at least substantially counter to the second direction.

The spreading conveyor can comprise at least one particle discharging portion which is located above the supply of tobacco particles in the magazine and can be provided with at least one opening extending at an oblique angle to the third direction The layer is normally converted into two continuous tobacco streams at least one of which normally contains a surplus of tobacco. The apparatus then further comprises means for removing the surplus from the stream or streams, and means for conveying the removed surplus to the spreading conveyor for admission into the magazine. The spreading conveyor can comprise a platform, and the conveying means then comprises a discharge end which delivers the removed surplus onto the platform.

The magazine can comprise a partition which divides the supply into two halves each having a width corresponding to half the predetermined width.

The spreading conveyor can include two particle discharging portions each of which makes with the third direction an oblique angle and each of which delivers particles to a different half of the supply in the magazine. The spreading conveyor preferably further comprises a sidewall for each of the particle discharging portions. The platform of such spreading conveyor can include two discharge ends each of which is disposed above a different half of the supply in the magazine. The discharging portions of the spreading conveyor can extend transversely of the third direction.

At least one of the intercepting and spreading conveyors can comprise a substantially horizontal vibratory trough.

In accordance with another embodiment, the feeding means includes means for delivering the flow of tobacco particles in a first direction (e.g., substantially vertically downwardly) and the homogenizing means of such apparatus can comprise a first conveyor which receives a first portion of the thus delivered flow and includes means for advancing tobacco particles in a second direction transversely of the first direction and a second conveyor which receives a second portion of the thus delivered flow and includes means for advancing tobacco particles in a third direction transversely of the first direction and at least substantially counter to the second direction.The first and second conveyors (each of which can be termed a combined intercepting and spreading conveyor) define an elongated clearance which is preferably inclined relative to the second and third directions, and such conveyors include particles discharging portions which are adjacent the clearance and over which the particles advance into the clearance to descend onto the supplv in the magazine.

In accordance with a further embodiment, the homogenizing means comprises two crossing ducts each having an inlet which receives a portion of the flow and an outlet which discharges the respective portion of the flow into the magazine. The arrangement is preferably such that the inlet of one of the ducts is located above a first half and the outlet of such one duct is located above a second half of the magazine.

The inlet of another duct is then located above the second half and the outlet of such other duct is located above the first half of the magazine.

In accordance with still another embodiment, the homogenizing means can comprise a plurality of particle distributing elements which are disposed in the flow of tobacco particles being fed toward the magazine. The distributing elements can include pivotable flaps and such homogenizing unit further comprises means for pivoting the flaps, preferably in synchronism back and forth about discrete axes.

In accordance with a further embodiment of the invention which can be resorted to when the flow contains at least partially segregated shorter and longer tobacco particles, the homogenizing means includes means for distributing the shorter particles into and substantially the full width of the supply of tobacco particles in the magazine. Such homogenizing means can further comprise a first conveyor which spreads the longer particles the full width of the magazine, and the distributing means then comprises a second conveyor which spreads the shorter particles onto the first conveyor so that the latter spreads the longer particles, as well as the shorter particles, the full width of the supply of particles in the magazine. The first conveyor can extend longitudinally of the elongated magazine, and the second conveyor can extend transversely of the magazine.The homogenizing means can further comprise a third conveyor which is at least substantially parallel to the first conveyor and receives the flow from the feeding means. The means for conveying the removed surplus from the streams is preferably designed to convey the surplus from the surplus removing means to the first conveyor.

The conveying means for the surplus can be parallel to the second conveyor. The third conveyor can comprise a tobacco discharging portion above the conveying means, and the conveying means can be provided with a particle discharging end which is disposed above the second conveyor and extends substantially at right angles to the discharging portion of the third conveyor. The particle discharging portion of the second conveyor can be disposed above the first conveyor, and the first conveyor can include means (such as a vibratory trough) for transporting particles of tobacco in a predetermined direction making an oblique angle with the particle discharging portion of the first conveyor.

In accordance with a further embodiment of the invention, the homogenizing means comprises a rotary part which can be termed a winnower because it is designed to propel at least some particles of the flow in a predetermined direction. Such homogenizing means further comprises a first conveyor which intercepts the propelled particles, and a second conveyor which receives particles from the first conveyor and spreads the thus received particles the full width of the magazine. The feeding means of such apparatus can comprise a rotary element and means for rotating the rotary element in a predetermined direction and such homogenizing means preferably further comprises means for rotating the winnower in the predetermined direction. The winnower can be located at a level beneath the rotary element of the feeding means.

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 its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain presently preferred specific embodiments with reference to the accompanying drawing.

FIG. 1 is a fragmentary schematic partly front elevational and partlv vertical sectional view of a twin cigarette rod making machine wherein the distributor or hopper is equipped with a tobacco homogenizing, uniformizing or declassifying unit embodying one form of the present invention; FIG. 2 is a side elevational view of a portion of the distributor as seen from the right-hand side of FIG. 1; FIG. 3 is a fragmentary horizontal sectional view substantially as seen in the direction of arrows from the line III-III in FIG. 2; FIG. 4 is a fragmentary schematic partly front elevational and partly vertical sectional view of a distributor which is equipped with a modified homogenizing, uniformizing or declassifying unit; FIG. 5 is a horizontal sectional view substantially as seen in the direction of arrows from the line V-V in FIG. 4; ; FIG. 6 is a horizontal sectional view substantially as seen in the direction of arrows from the line VI-VI in FIG. 4; FIG. 7 is a view similar to that of FIG. 4 but showing a third homogenizing, classifying or uniformizing unit; FIG. 8 is another view of the third unit substantially as seen from the right-hand side of FIG. 7; FIG. 9 is a plan view of the structure which is shown in FIG. 8; FIG. 10 is a view similar to that of FIG. 4 or 7 but showing a fourth homogenizing, uniformizing or declassifying unit; FIG. 11 is a different view of the fourth unit substantially as seen from the right-hand side of FIG. 10; FIG. 12 is a fragmentary front elevational view of a distributor which is equipped with a fifth homogenizing, uniformizing or declassifying unit; FIG. 13 is a different view of the fifth unit substantially as seen from the right-hand side of FIG. 12;; FIG. 14 is a view similar to that of FIG.

4 or 7 but showing a sixth homogenizing, uniformizing or declassifying unit; FIG. 15 is a different view of the unit of FIG. 14; FIG. 16 is a schematic horizontal sectional view substantially as seen in the direction of arrows from the line XVI-XVI of FIG. 15; and FIG. 17 is a view similar to that of FIG.

15 but showing a further homogenizing, uniformizing or declassifying unit.

FIGS. 1 to 3 illustrate certain details of a twin rod cigarette making machine having a distributor which contains an apparatus embodying one form of the present invention. The distributor comprises a socalled primary or first distributor 2 having a magazine 1 for reception and storage of a supply 4 of tobacco particles. Such particles are supplied, either continuously or in batches, by a pneumatic feeding unit including a gate 3 at a level above the magazine 1. The gate 3 receives signals, to deliver a discontinuous flow in the form of one or more batches or a continuous flow, from an optoelectronic detector or sensor 6 which monitors the level of the top surface of the supply 4 and transmits appropriate signals to one or more flaps forming part of the gate 3 and being pivotable or otherwise movable between open and closed positions.Reference may be had, for example, to commonly owned U.S. Pat, No. 5,009,238 granted April 23, 1991 to Heitmann for "Apparatus for supplying fibrous material to machines for simultaneouslv producing a plurality of cigarette rods" which describes and shows gates capable of being put to use in the distributor of FIGS. 1 to 3.

The contents of the magazine 1 must be replenished, either continuously or at intervals, because this magazine serves to supply a flow of tobacco particles to a second or main magazine 11 at a level below the supply 4. The means for feeding a flow of tobacco particles from the bottom zone of the magazine 1 into the magazine 11 comprises a rotary drum- or roller-shaped transfer element or rake 7 with radially extending pins and a rotary drum- or roller-shaped combing element 8 having radially extending pins cooperating with the pins of the rake 7 to deliver a shower of tobacco particles in directions which are indicated by arrows.The arrangement is preferablv such that the supply 9 of tobacco particles in the main magazine 11 is replenished (either continuously or intermittently) for the purpose of ensuring that the upper level of the supply 9 will fluctuate very little or not at all. To this end, the magazine 11 contains one or more photoelectronic detectors or sensors 12 (e.g., a row of sensors) which generate signals denoting the level of the upper surface of the supply 9, and such signals are used to control the motor or motors which drive the transfer elements 7 and 8, i.e., the components of means for feeding a flow of tobacco particles toward the magazine 11.

One side of the main magazine 11 is defined by the upwardly moving reach or stretch of an elevator conveyor 13 having tobacco entraining or withdrawing elements in the form of pockets (reference may be had, for example, to commonly owned U.S. Pat. No. 4,185,644 granted January 29, 1980 to Heitmann et al. for "Distributor for cigarette makers or the like") serving to deliver batches of tobacco particles into the open upper end of a substantially upright gathering duct 16.

The batches which are entrained by the pockets of the elevator conveyor 13 in the direction of arrow 47 are equalized by a rotary paddle wheel 14 which brushes the surplus off the oncoming batches and returns the removed surplus into the magazine 11.

The duct 16 accumulates a column of tobacco particles, and the height of such column is monitored by a battery of photoelectronic detectors (reference may be had to the aforementioned U.S. Pat. No. 4,185,644 and to commonly owned U.S. Pat. No. 4,172,515 granted October 30, 1979 to Wochnowski for "Method and apparatus for supplying tobacco to cutting machines") which control the motor for the elevator conveyor 13 so that the level of the upper surface of the column of tobacco particles in the duct 16 remains at least substantially constant.

The outlet 17 at the lower end of the duct 16 is adjacent a tobacco removing unit including a rotary carded wheel 18 and a rotary picker roller 19 which is driven at an RPM greatly exceeding the RPll of the drum 18.

The carding of the roller 18 draws a layer of tobacco particles from the outlet 17 of the duct 16, and the pins of the picker roller 19 expel such layer from the carding to form a shower which descends in the direction of arrow 21 in a downwardly tapering wedgelike channel 22. The channel 22 guides the shower of tobacco particles past a plenum chamber 23 which is provided with one or more nozzles serving to discharge jets of compressed air in the direction of arrow 24, i.e., substantially at right angles to the direction of advancement of tobacco particles in the channel 22.

The plenum chamber 23 and its nozzle or nozzles act as a classifier which segregates lighter tobacco particles from heavier tobacco particles (such as fragments of tobacco ribs). Thus, the lighter particles are deflected in the direction of arrow 24 whereas the heavier particles penetrate through the curtain of jets of compressed air which are discharged from the nozzle or nozzles of the plenum chamber 23 and continue to descend (note the arrow 26 in FIG. 2) to be evacuated from the distributor by way of a rotary cell wheel 27 and thereupon by way of an evacuating duct 28.Some lightweight tobacco particles which are entrained by the heavier particles in the direction of arrow 26 and which pass through the cell wheel 27 are lifted by an ascending air stream in a channel-29 to be reunited with the segregated lightweight particles in a merger zone 30 which is located to the left of the plenum chamber 23 (as viewed in FIG. 1). The lightweight particles which have passed through the cell wheel 27 rise in the channel 29 due to the injector effect of one or more nozzles receiving compressed air from a plenum chamber 31.

The lighter tobacco particles which enter the merger zone 30 under the action of compressed air issuing from the plenum chambers 23 and 31 are caused to form a relatively wide and relatively thin layer or carpet which advances along the concave side of a support 32 under the action of compressed air flowing in the direction of arrow 24 and under the action of additional air which is supplied by the compressed air nozzle or nozzles of one or more additional plenum chambers (one shown at 33).The width of the layer or carpet of tobacco particles on the concave surface of the support 32 (as measured at right angles to the plane of FIG. 1) matches or approximates the width of the supply 9 in the magazine 11 and is such that the quantity of tobacco in the carpet suffices for the making of two tobacco streams which are formed at the undersides of two endless belt conveyors 37, 38 The conveyors 37, 38 receive tobacco particles from discrete deflectors 32a, 32b which follow the support 32 and guide the respective halves of the carpet or layer in directions which are indicated bv the arrows 34, 36, respectively. Reference may be had to the aforementioned U.S. Pats. Nos.

5,009,238 and 4,889,138. The air streams which are discharged by the nozzles of the plenum chambers 23 and 33 cause the carpet or layer on the support 32 and the narrower carpets or layers on the deflectors 32a, 32b downstream of the support 32 to closely follow the adjacent surfaces of the parts 32, 32a, 32b on their way into the tobacco channels beneath the respective conveyors 37 and 38. The surplus of entraining air is caused to enter an expansion chamber of the type described and shown in the aforementioned U.S. pats.

Nos. 5,009,238 and 4,889,138. The manner in which the streams at the under sides of the lower reaches of the conveyors 37, 38 are advanced, relieved of surplus tobacco and draped into webs of cigarette paper or other suitable wrapping material to form two discrete cigarette rods is or can be the same as described, for example, in commonly owned U.S. Pat. No. 4,893,640 granted January 16, 1990 to Heitmann et al for "Multiple-rod cigarette making machine" to which reference may be had, if necessary.

The mode of operation of the feeding unit 3 is such that a certain classification of supplied tobacco particles takes place and that such classified tobacco particles enter the preliminary or primary distributor 2. On the other hand, it is important and highly desirable that the mixture of lighter and heavier as well as shorter and longer tobacco particles in the two layers advancing in the directions of arrows 34, 36 be homogeneous so that the qualities of cigarettes which are obtained by severing one of the two cigarette rods will be the same as the quality of cigarettes which are obtained as a result of severing of the other rod.

The reasons for a certain classification of tobacco particles in the feeding unit 3 prior to delivery of batches into the magazine 1 are described, for example, in commonly owned copending patent application Serial No. filed August 15, 1991 by Heitmann for "Apparatus for feeding tobacco to distributors of rod making machines". Thus, relatively long tobacco shreds are likely to accumulate in a certain part of the magazine 1 and certain other portions of this magazine are likely to accumulate relatively short tobacco shreds.

In order to eliminate such accumulations of certain types of tobacco particles in different portions of the distributor, the latter comprises a device (shown at 39) for homogenizing, declassifying or intermixing tobacco particles between the magazines 1 and 11 so that each unit width of the supply 9 in the magazine 11 next to the elevator conveyor 13 contains a homogeneous mixture of shorter and longer as well as lighter and heavier tobacco particles, primarily shreds of tobacco leaf laminae.

Such distribution thereupon remains unchanged all the way to the lower reaches of the conveyors 37, 38 except that the aforediscussed plenum chambers 23 and 31 ensure segregation of relatively heavy tobacco particles (which normally constitute fragments of tobacco ribs and stem) from lighter tobacco particles.

The homogenizing, declassifying or intermixing device 39 (hereinafter called homogenizer for short) comprises an intercepting conveyor 41 in the path of the flow of tobacco particles which are advanced by the rotary elements 7, 8 and a distributing or spreading conveyor 42 beneath the conveyor 41. The conveyors 41 and 42 are driven to advance tobacco particles along substantially parallel paths but in opposite directions (note the arrows 43 and 44 in FIG. 2), namely toward and away from the observer of FIG. 1. Each of the illustrated conveyors 41, 42 comprises an elongated vibratory conveyor having a tobacco conveying trough which is substantially horizontal and is mounted on several sets of suitably inclined leaf springs 52, 53, respectively.

The trough of the upper conveyor 41 receives motion from a first prime mover 54 which drives a first eccentric, and the trough of the lower conveyor 42 receives motion from a second prime mover 56 through a second eccentric.

It will be noted that the inclination of the leaf springs 52 for the upper conveyor 41 relative to a vertical plane is counter to the direction of inclination of leaf springs 53 for the lower conveyor 42.

The trough of the conveyor 41 receives the flow of tobacco particles from the rotary elements 7, 8 and advances such particles in the direction of arrow 43 to its right-hand end (as seen in FIG. 2) where the particles descend into an intermediate portion of the trough of the conveyor 42. The bottom wall of the trough of the conveyor 42 has a discharging portion bounding transversely extending elongated slot-shaped openings 46 (see FIG. 3) which permit homogenized tobacco particles to descend into the magazine 11.

The openings 46 form at least one row which extends the full width of the bottom wall of the trough of the lower conveyor 42, i.e., all the way between the sidewalls of this trough. The tobacco particles which form the at least partly homogenized mixture leaving the discharge end of the conveyor 41 are advanced in the direction of arrow 44 and descend through the openings 46 so that they are uniformly or nearly uniformly distributed across the full width of the magazine 11 (i.e., at right angles to the plane of FIG. 1). Thus, the elongated batches of tobacco particles which are entrained by the pockets of the elevator conveyor 13 in the direction of arrow 47 are homogeneous, i.e., each such batch contains a uniform mixture of shorter and longer as well as heavier and lighter tobacco particles.

FIGS. 2 and 3 shows that one end portion 48 of the lower conveyor 2 extends bevond the respective end of the upper conveyor 41 in order to provide room for admission of surplus tobacco which is trimmed off the streams at the undersides of the lower reaches of the conveyors 37, 38 and is returned into the distributor by a conveying means here shown as a belt conveyor 49.

The end portion 48 of the conveyor 42 can be said to constitute a substantially horizontal platform or table which receives all of the removed surplus. The conveyor 49 delivers the surplus in the direction of arrows 51, and such surplus is deflected upon reaching the platform 48 so that it advances in the direction of arrows 44 jointly with tobacco particles which advance beyond the oblique discharqe end 41a of the upper conveyor 41. This ensures that the removed surplus is uniformly distributed across the full width of the supply 9 in the magazine 11.

It has been found that the homogenizer 39 contributes significantly to uniformity of tobacco in the wide batches which are conveyed by the pockets of the elevator conveyor 13, to uniformity of tobacco in the gathering duct 16, to uniformity of tobacco layers or carpets on the support 32 and on the deflectors 32a, 32b, and to uniformity of tobacco streams which grow at the undersides of and are entrained by the lower reaches of the conveyors 37, 38. Therefore, the quality of cigarettes which are obtained by subdividing one of the two cigarette rods is the same as the quality of cigarettes which are obtained as a result of repeated severing of the other cigarette rod.

The width of the supply 9 in the main magazine 11 preferably matches the width of the column of tobacco particles in the duct 16 and the width of the carpet or layer on the support 32. The direction in which the flow of tobacco particles is advanced by the rotary feeding elements 7, 8 is substantially normal to the directions (arrows 43, 44) of advancement of tobacco particles along the paths which are defined bv the vibratory troughs of the conveyors 41, 42. The tobacco discharging portion which surrounds the openings 46 of the spreading conveyor 42 makes an oblique angle with the directions which are indicated by the arrows 43 and 44.

FIGS. 4, 5 and 6 illustrate certain details of a modified twin rod making machine. All such parts which are identical with or clearly analogous to corresponding parts of the machine of FIGS. 1 to 3 are denoted by similar reference characters plus 100. The magazine 111 contains an upright partition 157 which divides its internal space into two neighboring compartments preferably having identical widths. The partition 157 is parallel to the plane of FIG. 4.

A second partition 158 is provided and can form part of the spreading conveyor 142. The bottom wall of the trough of the conveyor 142 comprises two particle discharging portions or ends 146 at opposite sides of the partition 158 and at opposite sides of the partition 157. The discharging portion 146 include edge faces which make oblique angles with the longitudinal direction (arrow 144) of the conveyor 142 and each of which extends from the partition 158 to the respective sidewall 19, 161 of the trough of the conveyor 142. The discharging portions 146 are staggered relative to each other in the direction of arrow 144 so that two spaced apart portions 162 of the conveyor 142 do not deliver into the supply 109 of tobacco particles in the magazine 111 any tobacco particles which are received from the upper conveyor 141.

Otherwise stated, some of the tobacco particles which are withdrawn from the supply 104 in the upper magazine 101 can reach the supply 109 by advancing beyond the two discharging portions 146.

The purpose of the spaced-apart portions 162 is to introduce returned surplus tobacco particles into selected portions of the two halves of the supply 109 in the magazine 111, namely in such a way that the returned surplus tobacco is repeatedly removed from the streams on the conveyors 37, 38 by the trimming devices at the conveyors 37, 38 (reference may be had to the aforementioned U.S. Pat, o. 4,893,640 which shows discrete trimming devices adjacent the undersides of the lower reaches of the stream transporting conveyors corresponding to the conveyors 37, 38 in FIG. 1).To this end, the extension or platform 148 of or on the conveyor 142 is positioned to receive (via conveyor 149) all of the surplus tobacco (i.e., the surplus which is being removed from the stream at the underside of the conveyor 37 as well as the surplus which is being removed from the stream at the underside of the conveyor 38).

The conveyor 149 discharges returned surplus tobacco into a chute 164 which is reciprocable in directions indicated by a double-headed arrow 163 in order to ensure uniform distribution of returned surplus tobacco particles on both halves of the platform 148, namely on those halves which are disposed at opposite sides of a third partition 166 above the upper side of the platform.

The platform 148 has straight transversely extending discharge ends 167, 168 which are normal to the directions (arrow 163) of reciprocatory movement of the chute 164. The discharge ends 167, 168 discharge returned surplus tobacco particles only into those parts of the tobacco supply 109 in the magazine 111 which are located beneath the respective portions 162 of the conveyor 142. This ensures that the tobacco carpets on the deflectors 32a, 32b deliver recycled surplus tobacco only to those parts of the streams at the undersides of lower reaches of the conveyors 37, 38 which are to be acted upon by the respective trimming or equalizing devices.

The conveyor 142 is further provided with a pivotable flap 169 which can be adjusted to ensure uniform distribution of tobacco on both halves of the conveyor 142.

An important advantage of the apparatus of FIGS. 4 to 6 is that the particles of surplus tobacco are circulated along endless paths a portion of each of which is defined by the magazine 111. Such mode of treating surplus tobacco which is removed from the streams at the undersides of the lower reaches of the conveyors 37, 38 ensures that the trimming devices repeatedly remove the same tobacco particles so that the other particles are not subjected to a comminuting action, i.e., the rod-like tobacco fillers which advance beyond the trimming stations contain high percentages of desirable long tobacco shreds. On the other hand, the relatively short shreds of surplus tobacco can properly fill the valleys between the hills at the undersides of tobacco streams which are built at the undersides of lower reaches of the conveyors 37 and 38.It has been found that, quite surprisingly, renewed circulation of surplus tobacco along endless paths does not result in excessive shortening of particles which form the surplus.

FIG. 7, 8 and 9 show certain details of a further machine wherein the homogenizer 239 between the magazines 201 and 211 of the distributor constitutes a further modification of the homogenizer 39. All such parts of the structure of FIGS. 7 to 9 which are identical with or clearly analogous to corresponding parts of the machine of FIGS. 1 to 3 are denoted by similar reference characters plus 200. The difference between the homogenizer 239 and the homogenizers 39, 139 is that the homogenizer 239 comprises two conveyors 271, 272 which are mounted at or close to the same level i.e., it is not necessary to mount one of these conveyors at a level above the other conveyor.The conveyors 271, 272 have elongated particle discharging portions with edges 273, 274 which extend longitudinally of these conveyors (i.e., nearly in parallelism with the directions of transport of tobacco particles thereon) and define an elongated obliquely extending clearance or gap 276 for discharge of tobacco particles into the supply 209 in the magazine 211. The conveyor 271 is mounted on leaf springs 278 and is driven hy a prime mover 282 through the medium of an eccentric 283 which reciprocates the conveyor 271 in such a way that tobacco particles which descend onto it are advanced in the direction of arrow 277.The conveyor 272 is mounted on leaf springs 281 (which are inclined relative to the leaf spring 278) and the conveyor 272 is also driven by the prime mover 282 by way of a discrete second eccentric 284 so that the tobacco particles which descend onto the conveyor 272 are caused to advance in the direction of arrow 279. Tvo pivotable flaps 286, 287 above the conveyors 271, 272 ensure uniform distribution of tobacco particles which are supplied by the rotary elements 207, 208 of the feeding means, i.e., which are withdrawn from the supply in the magazine 201. The clearance 276 extends the full width of the magazine 211 (as seen at right angles to the plane of FIG. 7).

All such parts of the structure of FIGS. 10 and 11 which are identical with or analogous to corresponding parts of the structure of FIGS. 1 to 3 are denoted by similar reference characters nlus 300.

The homogenizer 339 comprises two crossing chutes or ducts 388, 389 each of which has an inlet (391, 392) receiving tobacco particles from a different half of the magazine 301 and each of which has an outlet delivering such particles to the opposite half of the magazine 311.

Thus, the inlet 391 of the duct or chute 388 is disposed below and receives tobacco particles from the left-hand half of the magazine 301 (as viewed in FI. 11) and this chute or duct delivers the particles along a first path into the right-hand half of the magazine 311. The inlet 392 of the duct or chute 389 receives tobacco particles from the right-hand half of the magazine 301 and this duct delivers the thus received particles along a second path into the left-hand half of the magazine 311. The two paths cross each other above the magazine 311 between the inlets and the outlets of the ducts 388, 389.The unobstructed median portion and end portions of the lower end of the magazine 301 are free to discharge tobacco particles directly into the respective (median and end) portions of the magazine 311 (at a rate which is determined by the corresponding portions of the rotary elements 307 and 308 of the means for feeding a flow of tobacco particles from the supply 304 in the magazine 301 toward the supply 309 in the magazine 311.

The homogenizer 339 also ensures pronounced intermixing of all types of tobacco particles not later than when such particles enter the magazine 311. This, in turn, ensures that the composition of rod-like fillers in each of the two cigarette rods is the same.

An important advantage of the homogenizer 339 is that it need not utilize any moving parts, i.e., the ducts 338, 389 can be fixedly mounted in the distributor at a level above the supply 309 and beneath the rotary element 308 of the tobacco flow feeding means.

FIG. 12 and 13 show a further homogenizer 439 which is installed above (rather than below) the rotary elements 407, 408. All such parts of the structure of FIGS. 12 and 13 which are identical with or analogous to corresponding parts of the structure of FIGS. 1 to 3 are denoted by similar reference characters plus 400.

The homogenizer 439 comprises two mobile particle distributing elements in the form of flaps 493, 494 which are installed beneath the gate or gates 403 and can be pivoted, either jointly (in synchronism) or independently of each other, about discrete parallel horizontal axes to direct tobacco particles against selected portions of the rotary elements 407 and 408.

The space between the flaps 493, 494 and the rotary elements 407, 408 is divided into two eaual compartments by a partition 496 which is parallel to the plane of FIG. 12 and is preferably located midway between the ends of the rotary elements 407, 408. The flaps 493, 494 can be pivoted back and forth, either continuously or at intervals. The means for pivoting the flaps can comprise a reversible motor or the like, not shown.

The means for feeding a flow of tobacco particles toward the flaps 493, 494 of the homogenizer 439 includes the pneumatic conveyor and its gate 403.

FIGS. 14 to 16 show the distributor and certain other constituents of a multiple cigarette rod making machine which constitutes a further modification of the machine of FIGS. 1 to 3. All such parts of the machine of FIGS. 14-16 which are identical with or analogous to the corresponding parts of the machine of FIGS. 1-3 are denoted by similar reference characters plus 500. The homogenizer 539 is located at a level beneath the rotary elements 507, 508 of the flow feeding means and is designed to ensure uniform distribution of all kinds of tobacco particles the full width of the tobacco supply 509 in the magazine 511.

The intercepting conveyor 541 of the homogenizer 539 is installed at a level above the spreading conveyor 542. The upper conveyor 541 is mounted on inclined leaf springs 552. The trough of the conveyor 541 is vibrated by an eccentric forming part of a prime mover 554. Analogously, the trough of the lower conveyor 542 is mounted on leaf springs 553 and is vibrated by a discrete second eccentric which receives torque from a prime mover 556. The conveyor 541 advances tobacco particles in the direction of arrow 543, and the conveyor 542 advances tobacco particles in the direction of arrow 544. The bottom wall of the vibratory trough of the conveyor 542 has oblique or slanting openings 546 corresponding to the openings 46 in-FIG. 3 and serving to permit gravitational descent of homogenized tobacco into the supply 509 within the magazine 511.

A conveying means here shown as a belt conveyor 549 is provided to advance removed surplus tobacco particles in the direction of arrows 551.

The homogenizer 539 further comprises a distributing conveyor 597 in the form of a vibratory conveyor having an elongated trough mounted on leaf springs 598 and being reciprocable by an eccentric drive 599 so that the tobacco particles which have been caused or permitted to descend onto the bottom wall of the trough of the conveyor 597 advance in the direction of arrow 595. The distributing conveyor 597 is located at a level between the conveyors 541, 542. An obliquely extending particle discharging portion 590 of the conveyor 597 has an elongated edge over which tobacco particles descend onto the bottom wall of the troughshaped conveyor 542.

The conveyor 549 has an oblique particle discharging end 585 with an edge face which extends at an angle of substantially or exactly 90" to the particle discharging portion 580 of the intercepting conveyor 541.

Tobacco particles which are acted upon by the rotary element 507 descend at right angles to the axis of the element 507 onto the intercepting conveyor 541 of the homogenizer 539. Such particles include short tobacco shreds 575 which are delivered to and concentrate on certain portion or portions of the intercepting conveyor 541. The latter further receives longer tobacco shreds 570 in part directly from the magazine 501, and all tobacco particles on the conveyor 541 are advanced laterally out of the distributor and onto the distributing conveyor 597. The latter effects uniform mixing of shorter particles 575 with longer particles 570 as a result of deflection in the direction of arrow 595 and renewed deflection after advancement beyond the oblique edge face of the particle discharging portion 590 of the conveyor 597.The thus intermixed tobacco particles descend onto the spreading conveyor 542 to be discharged into the magazine 511 through the openings 546 in the bottom wall of the conveyor 542.

An advantage of the homogenizer 539 is that it ensures highly satisfactory intermixing of shorter tobacco shreds 575 with the longer shreds 570 by the simple expedient of employing an additional conveyor 597 which transports shorter shreds at right angles to the directions of transport of longer shreds by the conveyors 541 and 542. The conveyor 597 receives shorter shreds 575 from one marginal portion of the conveyor 541 and transports the thus received shorter shreds transversely of and delivers them to one end of the conveyor 542. This ensures that each portion of the conveyor 542 receives shorter shreds 575 which are caused to advance toward and to pass (with longer shreds 570) through the openings 546 and to descend onto the supply 509 in the magazine 5111 at least substantially the full width of such supply. The conveyor 597 further receives recirculated surplus tobacco (from the conveyor 5n9) and ensures the transfer of such tobacco into the supply 509 via openings 546 in the conveyor 542.

FIG. 17 shows a further homogenizer 639 forming part of a distributor in a machine or making multiple cigarette rods. All such parts of the structure of FIG. 17 which are identical with or are analogous to corresponding parts of the machine of FIGS. 1 to 3 are denoted by similar reference characters plus 600.

The homogenizer 639 comprises a rotary conveyor 665 which acts not unlike a winnower (hereinafter called winnower) and intercepts tobacco particles descending from the rotary elements 607, 608 to propel such particles onto the intercepting conveyor 641. The winnower 665 ensures thorough intermixing of shorter tobacco particles 675 which descend substantially vertically with the longer tobacco shreds 670 which are transferred by the rotary elements 607, 608.The intercepting convevor 641 transports the mixture of particles 670 and 675 at right angles to the plane of FIG. 17 in a first direction and delivers successive increments of the mass of tobacco particles thereon to the spreading conveyor 642 which advances the particles in the opposite direction (again at right angles to the plane of FIG. 17) prior to discharging the repeatedly intermixed particles into the supply 609 in the magazine 611.

The spreading conveyor 642 further receives surplus tobacco which is supplied by the conveyor 649 in the direction of arrow 651.

All embodiments of the improved apparatus exhibit the advantage that they can effectively counteract classification of tobacco particles which normally takes place, or is likely to take place, during transport by a pneumatic conveyor toward and into the predistributor of a rod making machine. The homogenizing operation is carried out practically immediately after the partially classified particles enter the distributor, and the thus homogenized particles are not classified again (save for removal of heavier particles including fragments of tobacco stem and/or ribs) on their way toward the stream forming and trimming stations.

Another important advantage of the improved method and apparatus is that they render it possible to ensure controlled recirculation or repeated circulation of surplus tobacco.

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 our contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the appended claims.

Claims (40)

1. A method of converting a layer of tobacco particles which has a predetermined width into two continuous tobacco streams, comprising the steps of establishing a supply of tobacco particles which has said predetermined width; withdrawing tobacco particles from the supply; building the layer from the withdrawn tobacco particles; and replenishing the supply of tobacco particles, including feeding a flow of tobacco particles toward the supply, intercepting at least a portion of the flow, and uniformly spreading the intercepted portion of the flow into and at least substantially the width of the supply.

2. The method of claim 1 of simultaneously converting the layer into two parallel tobacco streams, wherein said withdrawing step includes removing tobacco particles along the width of the supply.

3. The method of claim 1, wherein said feeding step includes effecting a movement of tobacco particles of the flow in a first direction, said intercepting step including advancing the intercepted portion of the flow along a first path in a second direction transversely of said first direction and said spreading step including advancing the particles along a third path in a third direction counter to said second direction.

4. The method of claim 3, wherein said spreading step further comprises showering the particles from the third path into the supply.

5. The method of claim 3 of converting said layer into two continuous streams which contain a surplus of tobacco particles, further comprising the steps of removing the surplus from the streams and conveying the removed surplus into said second path.

6. The method of claim 3, wherein said paths are substantially horizontal.

7. The method of claim 6, wherein at least one of said advancing steps comprises advancing the particles by a vibratory conveyor.

8. The method of claim 1, wherein said spreading step includes admitting the intercepted particles into crossing paths and advancing the particles into the supply along said crossing paths.

9. The method of claim 8, wherein said advancing step includes advancing substantially one half of intercepted particles along one of said paths and advancing the remaining intercepted particles along another of said paths.

10. The method of claim 1, wherein said spreading step includes changing the direction of intercepted particles in dependency on the distribution of intercepted particles.

11. Apparatus for forming a layer which contains tobacco particles and has a predetermined width and is to be converted into two continuous tobacco streams, comprising a magazine for a supply of tobacco particles, said supply having said predetermined width; means for withdrawing tobacco particles from the supply; means for converting the withdrawn particles into said layer; and means for replenishing the supply in said magazine, including means for feeding a flow of particles toward said magazine, and means for homogenizing at least a portion of said flow and for spreading the homogenized portion of the flow into and at least substantially the width of the supply.

12. The apparatus of claim 11 for forming a layer which is to be divided into two parallel streams, wherein said feeding means includes means for delivering at least a portion of said flow to said homogenizing means.

13. The apparatus of claim 11, wherein said feeding means includes means for delivering the flow in a first direction, said homogenizing means comprising a particle intercepting conveyor having means for advancing at least a portion of said flow along a first path in a second direction extending substantially transversely of said first direction and a spreading conveyor receiving particles from said intercepting conveyor and having means for advancing the particles along a second path extending in a third direction at least substantially counter to said second direction.

14. The apparatus of claim 13, wherein said spreading conveyor has at least one particle discharging portion extending at an oblique angle to said third direction.

15. The apparatus of claim 13 for forming a layer which is converted into two continuous tobacco streams containing a surplus of tobacco particles, further comprising means for removing the surplus from the streams, and means for conveying the removed surplus to said spreading conveyor

16 The apparatus of claim 15, wherein said spreading conveyor comprises a platform and said conveying means has a discharge end which delivers the removed surplus onto said platform.

17. The apparatus of claim 11, wherein said magazine comprises a partition which divides said supply into two halves each having a width corresponding to half said predetermined width.

18. The apparatus of claim 17, wherein said spreading conveyor has two particle discharging portions each of which makes with said third direction an oblique angle and each of which delivers particles to a different half of the supply in said magazine.

19. The apparatus of claim 18, wherein said spreading conveyor further comprises a sidewall adjacent each of said particle discharging portions.

20. The apparatus of claim 17 for forming a layer which is converted into two continuous tobacco streams each of which contains a surplus of tobacco particles, further comprising means for removing the surplus from the streams, a platform adjacent said spreading conveyor and having two discharge ends each disposed above a different half of the supply in said magazine, and means for conveying the removed surplus to said platform for delivers into the magazine over said discharging portions.

21. The apparatus of claim 20, wherein said discharging portions extend transversely of said third direction.

22. The apparatus of claim 13, wherein at least one of said conveyors includes a substantially horizontal vibratory trough.

23. The apparatus of claim 11, wherein said feeding means includes means for delivering the flow in a first direction, said homogenizing means comprising a first conveyor which receives a first portion of the thus delivered flow and includes means for advancing tobacco particles in a second direction transversely of said first direction and a second conveyor which receives a second portion of the thus delivered flow and includes means for advancing tobacco particles in a third direction transversely of said first direction and at least substantially counter to said second direction, said conveyors defining an elongated clearance which is inclined relative to said second and third directions and said conveyors including particle discharging portions adjacent said clearance.

24. The apparatus of claim 11, wherein said homogenizing means comprises two crossing ducts each having an inlet which receives a portion of said flow and an outlet which discharges the respective portion of the flow into said magazine.

25. The apparatus of claim 24, wherein said magazine has a first half and a second half, the inlet of one of said ducts being located above the first half and the outlet of said one magazine being located above the other half of said magazine, the inlet of the other of said ducts being located above the second half of said magazine and the outlet of said other duct being located above the first half of said magazine.

26. The apparatus of claim 11, wherein said homogenizing means comprises a plurality of mobile particle distributing elements disposed in the flow of tobacco particles which are fed toward said magazine.

27. The apparatus of claim 26, wherein said distributing elements include pivotable flaps and means for pivoting said flaps in synchronism back and forth about discrete axes.

28. The apparatus of claim 11, wherein said flow contains at least partially segregated shorter and longer tobacco particles, said homogenizing means including means for distributing the shorter particles into and substantially the full width of the supply in said magazine.

29. The apparatus of claim 28, wherein said homogenizing means further comprises a first conveyor which spreads the longer particles the full width of said magazine and said distributing means comprises a second conveyor which spreads the shorter particles onto said first conveyor.

30. The apparatus of claim 29, wherein said magazine is elongated and said first conveyor extends longitudinally of said magazine, said second conveyor extending transversely of said magazine.

31. The apparatus of claim 30, wherein said homogenizing means further comprises a third conveyor which is at least substantially parallel to said first conveyor and receives the flow from said feeding means.

32. The apparatus of claim 30 for forming a layer which is converted into two continuous tobacco streams each of which contains a surplus of tobacco particles, further comprising means for removing the surplus from the streams and means for conveying the surplus from said removing means to said first conveyor.

33. The apparatus of claim 32, wherein said conveying means is parallel to said second conveyor.

34. The apparatus of claim 32, wherein said third conveyor includes a tobacco discharging portion above said conveying means and said conveying means has a particle discharging end disposed above said second conveyor and extending substantially at right angles to the discharging portion of said third conveyor.

35. The apparatus of claim 29, wherein said second conveyor has a particle discharging portion which is disposed above said first conveyor, said first conveyor including means for transporting particles in a predetermined direction making an oblique angle with the particle discharging portion of said first conveyor.

36. The apparatus of claim 11, wherein said homogenizing means comprises a rotary winnower which propels at least some particles of the flow in a predetermined direction, a first conveyor which intercepts the propelled particles and a second conveyor which receives particles from said first conveyor and spreads the thus received particles the full width of said magazine.

37. The apparatus of claim 36, wherein said feeding means includes a rotary element and means for rotating said element in a predetermined direction, said homogenizing means further comprising means for rotating said winnower in said predetermined direction.

38. The apparatus of claim 37, wherein said winnower is located at a level beneath said rotary element.

39. A method of converting a layer of tobacco particles which has a predetermined width into two continuous tobacco streams, substantially as herein described with reference to the accompanying drawings.

40. Apparatus for forming a layer which contains tobacco particles and has a predetermined width and is to be converted into two continuous tobacco streams, substantially as herein described with reference to the accompanying drawings.