Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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
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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
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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
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2836
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
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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
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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
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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.
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