CA1142836A - Method and apparatus for transporting particles of tabacco in shredding machines - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
The channel between the convergent tobacco compacting upper and lower chain conveyors of a tobacco shredding machine receives particles of tobacco, especially tobacco ribs, from a vibrating trough which defines a path extending in substantial parallelism with the direction of travel of particles between the chain conveyors and on toward the cutting station. The trough effects preliminary homogenization and compacting of particles on their way toward the rear portion of the lower chain conveyor which extends rearwardly beyond the upper chain conveyor. The front portion of the trough is vibrated in such a way that the particles therein perform recurrent movements having predominantly vertical components, and the rear portion of the trough is vibrated so as to cause the particles therein to perform recurrent movements having predominantly horizontal components. This is achieved by mounting the front portion of the trough on leaf springs which make with a vertical plane a relatively large acute angle, and by mounting the rear portion of the trough on leaf springs which make with a vertical plane a relatively small acute angle.

Description

The present invention relates to a method and apparatus for delivering particles of tobacco to the severing station of a tobacco cutting machine, particularly to a methodandapparatus Eor transporting a cake of tobacco particles into the range of one or more knives in a tobacco shredding machine. Still more particularly, the invention relates to improvements in a method and apparatus for delivering tobacco particles along a path wherein the particles are gradually or stepwise condensed to form a cake which is thereupon converted into shreds or other types of tobacco fragments.
Presently known tobacco shredding machines comprise convergent upper and lower chain conveyors which form and deliver a cake of condensed tobacco particles into the range of orbiting knives on a rotary carrier whereby the knives cut across successive increments of the leader of the cake and convert the particles into smaller Eragments or shreds which can be delivered to a condi-tioning unit prior to transport into the magazine of a cigarette maker. The rear end of the lower chain conveyor extends beyond the rear end of the upper chain conveyor and receives a shower of tobacco particles from a duct or the like. The leader of the cake passes througha mouthpiece, a portion of which may constitute a counterknife for the orbiting knives of the shredding machine.
Apparatus of the just outlined character serve for the processing of tobacco particles in the form of leaves or ribs.
The processing (i.e., comminution) of ribs presents many problems, especially as concerns their orientation in the cake.
The orientation of ribs in the cake determines the extent to which the ribs adhere to or are interlaced with each other as well as the quality of fragments which are obtained as a result

- 2 -of severing successive increments of the cake by the orbiting knives.
A drawback of presently known systems which deliver tobacco particles to the chain conveyors of a shredding machine is that the particles which form the cake are oriented in random fashion. This affects the homogeneousness of the cake and often results in extraction (rather than severing) of relatively large particles from the front end of the cake. Large fragments of ribs are likely to affect the quality of the filler of a cigarette rod and/or to puncture the wrapping material (cigarette paper) which is used to convert the filler into a rod ready to be subdivided into discrete cigarettes or analogous smokers' products.
One feature of the invention resides in the provision of a method of comminuting particles of tobacco, such as ribs or leaves. The method comprises the steps of building up a stream of tobacco particles at a location which is remote from a cutting station, transporting the stream lengthwise toward the cutting station, condensing the stream during transport toward the cutting station, conveying the particles toward the aforementioned location along a predetermined path substantially (but not necessarily exactly) in the longitudinal direction of the stream, and agitating the particles in the path in a novel and improved way. The agitating step includes imparting to the particles a first recurrent movement having a predominantly horizontal component during movement of such particles along a first portion of the path which is remote from the aforesaid location, and imparting to the particles a second recurrent movement having a predominantly vertical component during movement of the particles along a second portion of the path which is located downstream of the first portion, i.e., which is nearer to the aforementioned location.
If the particles are tobacco ribs, the agitating step results in such orientation of the ribs i~ the aforementioned path that at least the majority of the ribs which reach the aforesaid location are substantially horizontal and extend transversely or nearly transversely of their path.
The path may be slightly inclined with respect to the longitudinal direction of the stream. For example, if the stream is horizontal, the path can be inclined forwardly and downwardly at an angle of approximately five degrees to the horizontal. In other words, the outlet of the second portion of the path is preferably located at a level below the first portion of the path.
Another feature of the invention resides in the provision of a machine for comminuting particles of tobacco, such as ribs or tobacco leaves, at a cutting station. The machine comprises means for transporting a stream of -tobacco particles lengthwise from a location which is remote from and on to the cutting station including a pair of sup~rimposed chain conveyors or other suitable means for condensing the stream between the location and the cutting station (the neighboring reaches of the chain conveyors preferably define a convergent path extending substantially from the location of stream formation and on to the cutting station), a set of orbiting knives or other suitable means for comminuting the particles in successive increments of the condensed stream at the cutting station, and conveyor means defining an elongated path which is at least substantially in line with the stream. The conveyor means has outlet means at the aforesaid location and defines 3l~4~ 6 an elongated path whereln the particles o~ tobacco advance toward the aforementioned location. The elongated path which is defined by the conveyor means has a first portion remote from and a second portion nearer to the outlet. The machine further comprises a chute or other suitable means for feeding particles of tobacco into the first portion of the elongated path, a first set of suitably inclined leaf springs or analogous means for imparting to the particles in the first portion of the elongated path a first recurrent movement having a predominantly horizontalcomponent, and a second set of suitably inclined leaf springs or other suitable means for imparting to the particles in the second portion of the elongated path a second recurrent movement having a predominantly vertical component. A mouthpiece is preferably disposed between the chain conveyors and thè
cutting station, and the condensed stream advances through the mouthpiece on its way into the range of orbiting knives at the cutting station.
The conveyor pre~erably includes a ~ibratory trough, the rear portion of which defines the first portion of the elongated path and the front portion of which defines the second portion of the elongated path. The leaf springs which support the rear portion of the trough preferably make with a vertical plane an angle of approximately 20 degrees, and the leaf springs which support the front portion of the trough preferably make with a ver-tical plane an angle of approximately 40 degrees. This insures that the particles in the first and second portions of the elongated path which is defined by the trough perform the aforediscussed recurrent movements, even if the trough is not exactly horizontal.
In accordance with another aspect of the invention a method of comminuting particles of tobacco, such as ribs of '''~

tobacco leaves, wherein a stream of tobacco particles is built up at a location remote from and is transported toward a cutting station, and wherein the stream is condensed during transport toward said station, an improvement comprises conveying particles of tobacco toward said location with agitation so as to precompact the tobacco particles which reach the location.
In accordance with yet another aspect of the invention a machine for comminuting particles of tobacco, such as ribs of tobacco leaves, at a cutting station, the combination of a transporting unit arranged to advance a stream of tobacco particles along a first path from a location which is remote from said cutting station to said cutting station and to condense the stream between said location and said station; conveyor means defining at least one elongated second path; said conveyor means having outlet means at said location; means for feeding particles of tobacco to said conveyor means whereby such particles advance toward and enter said location to form said stream; and means for agitating the particles in said second path to assist in precompacting the particles which reach said location.
The single Figure of the drawingis a schematic side - Sa -' `~`r~
,. ...

elevational view of a tobacco shredding machine proper and a schematic partly elevational and partly longitudinal sectional view of a tobacco delivering apparatus.
The tobacco cutting or shredding machine which is shown in the drawing comprises a frame or support for a transporting unit 3 including an upper endless chain conveyor 4 and a lower endless chain conveyor 6. The lower reach of the conveyor 4 slopes forwardly and downwardly, and the upper reach : of the chain conveyor 6 slopes upwardly and forwardly 50 that such reaches define a convergent substantially horizontal elongated path wherein the particles of tobacco (e.g., tobacco ribs 2) are transported in a direction to the left, i.e., in the longitudinal direction of the stream of tobacco particles which are converted into a cake prior to reaching a cutting or severing station 19. The leader of the cake advances into the range of orbiting knives or cutters 21 which are mounted at the periphery of a cylindrical carrier 22 installed in the frame and driven by a prime mover 23 here shown as an electric motor whose output element transmits torque to the shaft of the carrier 22 by way of a toothed-belt or chain transmission.
The sprocket wheels of the lower chain conveyor 6 are mounted on shafts which are journalled in the frame of the shredding machine. The front sprocket wheel of the chain conveyor 6 is rotated by a variable-speed prime mover 7 (e.g., an electric motor) through the medium of a toothed-belt or -chain transmission 16. The shaft 8 for the rear sprocket wheel of the upper chain conveyor 4 is also journalled in the frame;
however, the front sprocket wheel 9 of the upper chain conveyor 4 is movable up and down and is biased downwardly, as viewed ; 30 in the drawing, by a fluid-operated cylinder and piston unit 11 or analogous yieldable biasing means. The front sprocket wheel 9 is driven by a gear train 12, 13, 14 which derives motion from the front sprocket wheel of the lower chain conveyor 6.
The cutting edges of the knives 21 are sharpened by a grinding wheel 24 which is driven by a separate motor. The active surface of the grinding wheel 24 is treated by a dressing tool 26.
The outlet of the path between the chain conveyors 4 and 6 is defined by a mouthpiece including an upper portion 17 which shares the (up and down) movements of the front sprocket wheel 9 and a ]ower portion 18 which is fixedly secured to the frame and constitutes a counterknife for the orbiting knives 21.
The shreds which are formed in response to severing of successive increments of the cake are caused to descend into the inlet of a pneumatic conveyor which transports the shreds to the next processing station, e.g., to the drier of a conditioning unit which changes the moisture content of the shreds.
; The rear portion of the lower chain conveyor 6 extends rearwardly beyond the rear portion of the upper chain conveyor 4 and is disposed at a level below a location 1 (hereinafter ~ called stream building zone) which receives tobacco particles 2 - from an apparatus embodying one form of the invention. The apparatus comprises conveyor means including a trough-shaped vibratory conveyor 27 which defines an elongated path substantially or exactly in line with the elongated path between the chain conveyors 4 and 6. The outlet of the path which is defined by the conveyor 27 is located at the stream building zone 1. The means for agita-ting the particles 2 of tobacco in the trough 27 comprises an eccentric pin 37 on a disc 36 which is driven by a motor, not shown. The pin 37 is coupled to the trough 27 by a connecting rod 38. The trough 27 is mounted on leaf springs 23a, 28b which are secured -to the frame. When the eccentric 37 rotates, the trough 27 performs recurrent movements which cause the particles 2 to advance toward the stream building zone 1.
The means for feeding tobacco particles 2 into the rear portion of the trough 27 comprises a chute 33 which can deliver particles of tobacco at a variable rateO Such rate can be varied by a monitoring means including photocells 32 which are adjacent to the path of particles in the trough 27 and serve to monitor the upper level of the mass of particles in the trough.
When the height of such mass is too low, one of the photocells 32 transmits a signal to a control circuit which increases the rate of delivery of particles via chute 33. If the height of the mass in the trough 27 is excessive, the other photocell 32 transmits a signal which causes the control circuit to reduce the rate of tobacco feed. Thus, the photocells 32 cooperate with the control circuit to insure that the quantity of tobacco particles in the trough 27 is always within a desired range.
The exact manner in which the photocells 32 cooperate with the control circuit to insure that the upper level of the mass of tobacco particles 2 in the trough 27 remains within the optimum range for the formation of an acceptable cake forms no part of this invention. For example, the control circuit can transmit signals to a variable-speed motor which drives a conveyor serving to draw tobacco par-ticles from a hopper and to deliver the withdrawn particles into the chute 33. Also, the photocells 32 can control the motor 7.
The bottom wall of the trough 27 slopes slightly downwardly and forwardly, i.e., toward the zone 1. For example, this bottom wall can make an angle of 5 degrees with the direction of movement of the cake into the range of orbiting knives 21.
It has been found that the conveyor means including the trough 27 contributes to predictable orientation of particles 2 on their way toward the stream building zone 1. This, in turn, insures that the homogeneousness of the ca~e isconstant or nearly constant and also that the particles 2 (particularly ribs) assume such positions that, even though they cannot be readily extracted by the knives 21, the particles are converted into relatively long shreds which are best suited for the making of a satisfactory tobacco filler stream. As a rule, the particles 2 are substantially horizontal and extend transversely of the direction of transport along the path between the chains 4, 6 not later than when they reach the stream building zone l.
The vlbrating trough 27 insures a preliminary compacting or condensation of the tobacco particles 2. If the particles 2 are ribs, they are converted into a substantially homogeneous stream of interlaced particles even before they descend onto the upper reach of the lower chain conveyor ~.
Agitation of particles 2 in the trough 27 insures that the majority of particles assume a horizontal position not later than on arrival at the outlet of the trough. Some of the particles will make an acute angle with the direction of transport along the bottom wall of the trough 27; however, the majority of particles will extend at right angles to such direction. This insures the formation of a homogeneous or nearly homogeneous cake. Moreover, the knives 21 convert successive increments of the cake into elongated shreds which are more desirable than short tobacco.

Another importan-t advantage of the improved apparatus is that lts height is a fraction of the height of apparatus which are presently in use for delivery of tobacco particles to the compacting and transporting unit of a tobacco cutting or ~ -shredding machine. Presently known apparatus invariably employ an elongated vertical duct which accumulates a stack of tobacco particles at a level above the rear portion of the lower chain conveyor, and a rake or analogous means for intermittently advancing tobacco particles from the lower end of such duct into the space between the upper and lower chain conveyors of the transporting unit.
The bottom wall of the trough 27 which makes with a horizontal plane an angle of approximately 5 degrees defines an elongated path having a first portion more distant from and a second portion nearer to the stream building zone 1. The bottom wall of the trough 27 is or can be inclined forwardly and downwardly, i.e., toward the upper reach of the chain conveyor 6. The elongated elastic elements or leaf springs 28a make with a vertical plane a first acute angle of approximately 40 degrees.
The elongated elastic elements or leaf springs 28b make with a vertical plane an acute angle of approximately 20 degrees.
Owing to the aforediscussed inclination of leaf springs 28a and 28b, the motor 36 imparts to the front section or portion of the trough 27 and to the particles 2 therein a recurrent movement having a predominantly vertical component, and the rear portionor section of the trough 27 receives a recurrent movement having a predominantly horizontal component. This will be readily appreciated since the extent to which the front leaf springs 28a move the corresponding portion of the bottom wall of the trough 27 up and down is much more pronounced than the extent of up- and down-movement of the rear portion of this bottom wall under the action of leaf springs 28b. Pronounced up- and down-movements of the front portion of the bottom wall result in pronounced stratification of tobacco particles (e.g., ribs) 2 in the front portion of the trough 27, and the --superimposed strata of the accumulated and oriented particles are closely adjacent to each other, i.e., the body or stream of particles reaching the upper reach of the chain conveyor 6 is dense. This, in turn, insures that the front end of such stream does not tend to bulge upwardly (as at 39) and its constituents do not tend to change their orientation as a result of contact with particles on the chain conveyor 6. It has been found that the orientation of particles 2 which leave the zone 1 and enter the space between the chain conveyors 4, 6 does not change at all. There is no pileup and/or other undesirable shifting, bulging and/or analogous stray movements of particles leaving the zone 1. In the absence of pronounced stratification in the first or left-hand portion of the path which is defined by the trough 27, the particles 2 reaching the space between the chain conveyors 4, 6 would be likely to assume vertical or nearly vertical positions which, in turn, would affect the quality of the shredding action.
The particles 2 which are delivered by the chute 33 into the rear portion of the path defined by the trough 27 are moved substantially horizontally because the inclination of leaf springs 28b with respect to a vertical plane is relativelysmall.
Therefore, such particles are rapidly advanced toward the zone 1. This insures that the conveyor 6 receives a continuous stratified body of properly oriented particles 2 even if the rate at which the chute 33 delivers particles into the trough 27 fluctuates within a wide range. Thus, the rear portion of the trough 27 imparts movements in the general direction of movement of the cake, and the front portion of the trough imparts movements substantially at right angles to such direction.
The inclination of the bottom wall 29 can be varied without departing from the spirit of the invention. Also, the inclination of the leaf springs 28a, 28b can be changed, as long as the front portion of the trough 27 receives a recurrent movement having a predominantly vertical component and the rear portion of the trough 27 receives a recurrent movement having a predominantly horizontal component. The means for agitating the trough 27 can also be modified as long as the two portions of the trough are moved in a manner as outlined above.
The improved tobacco delivering apparatus is susceptible of many additional modifications. For example, the means for agitating the particles in the conveyor means can include means for regulating the amplitude and/or frequency of vibrations of the trough. Such adjustments will be carried out in order to insure that the rate of delivery of particles to the stream building zone matches or closely approximates the output of the cutting machine. The frequency and/or amplitude of vibrations can be changed when particles of a first type are followed by particles of a second type, when the speed of the chain conveyors is changed and/or for certain other reasons.
Furthermore, the monitoring means may be used to regulate the frequency and/or amplitude of vibrations of the trough or troughs to thereby insure an optimum rate of delivery of tobacco particles to the stream building zone.

Claims (16)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of comminuting particles of tobacco, such as ribs or tobacco leaves, comprising the steps of building up a stream of tobacco particles at a location remote from and transporting the stream lengthwise toward a cutting station;
condensing the stream during transport toward the cutting station; conveying the particles toward said location along a predetermined path substantially in the longitudinal direction of the stream; and agitating the particles in said path, including imparting to the particles a first recurrent movement having a predominantly horizontal component during movement of such particles along a first portion of said path which is remote from said location and imparting to the particles a second recurrent movement having a predominantly vertical component during movement of such particles along a second portion of said path which is nearer to said location than said first portion.

2. The method according to claim 1, wherein the particles of tobacco are ribs and said agitating step includes orienting the ribs in said path in such a way that at least the majority of ribs reaching said location are substantially horizontal and extend substantially transversely of said path.

3. The method according to claim 1, wherein said path is slightly inclined with respect to the longitudinal direction of the stream.

4. The method of claim 1, wherein said second portion of said path has an outlet which discharges particles into said location and said outlet is located at a level below the first portion of said path.

5. A machine for comminuting particles of tobacco, such as ribs or tobacco leaves, at a cutting station, comprising means for transporting a stream of tobacco particles lengthwise from a location which is remote from and on to said cutting station, said transporting means including means for condensing the stream between said location and said station; means for comminuting the particles in successive increments of the condensed stream at said station; conveyor means defining an elongated path which is at least substantially in line with said stream, said conveyor means having outlet means at said location and defining an elongated path wherein the particles advance toward said location, said path having a first portion remote from and a second portion nearer to said location; means for feeding particles into said first portion of said path;
means for imparting to the particles in said first portion a first recurrent movement having a predominantly horizontal component; and means for imparting to the particles in said second portion a second recurrent movement having a predominantly vertical component.

6. The machine as defined in claim 5, wherein said condensing means comprising two superimposed chain conveyors having neighboring reaches defining a convergent second path extending substantially from said location and on to said station.

7. The machine according to claim 5, further comprising a mouthpiece disposed intermediate said chain conveyors and said cutting station, the condensed stream passing through said mouthpiece on its way to said cutting station.

8. The machine according to claim 5, wherein said conveyor means includes a vibratory trough and each of said imparting means includes resilient elements supporting said trough.

9. The machine according to claim 8, wherein said trough includes a first portion defining said first portion of said path and a second portion which defines said second portion of said path, said resilient elements including a first set of leaf springs which are inclined with respect to a vertical plane and support said first portion of said trough and a second set of leaf springs which are also inclined with respect to a vertical plane and support said second portion of said trough, the inclination of said second set of leaf springs with respect to said vertical plane being more pronounced than the inclination of said first set of leaf springs.

10. The machine according to the claim 9, wherein the inclination of said first set of leaf springs with respect to said vertical plane is approximately 20 degrees, and the inclination of said second set of leaf springs with respect to said vertical plane is approximately 40 degrees.

11. In a method of comminuting particles of tobacco, such as ribs of tobacco leaves, wherein a stream of tobacco particles is built up at a location remote from and is transported toward a cutting station, and wherein the stream is condensed during transport toward said station, the improvement which comprises conveying particles of tobacco toward said location with agitation so as to precompact the tobacco particles which reach the location.

12. The improvement of claim 11 wherein said particles of tobacco are conveyed toward said location substantially in the longitudinal direction of said stream and along a substantially horizontal path.

13. The improvement of claim 11, wherein agitation is accomplished by vibrating the particles while conveying them toward said location.

14. In a machine for comminuting particles of tobacco, such as ribs of tobacco leaves, at a cutting station, the combination of a transporting unit arranged to advance a stream of tobacco particles along a first path from a location which is remote from said cutting station to said cutting station and to condense the stream between said location and said station; conveyor means defining at least one elongated second path; said conveyor means having outlet means at said location; means for feeding particles of tobacco to said conveyor means whereby such particles advance toward and enter said location to form said stream; and means for agitating the particles in said second path to assist in precompacting the particles which reach said location.

15. The improvement of claim 13, wherein said agitating means comprises means for vibrating said conveyor means.

16. The improvement of claim 14 wherein said transporting unit advances the stream lengthwise along a first substantially horizontal path and wherein said second path is substantially in line with said stream and is substantially horizontal.