[0001] The present invention relates to a tobacco feed and transport unit in a machine for
manufacturing tobacco products.
[0002] The prior art embraces cigarette makers equipped with a feeding and conveying unit
that comprises an infeed chamber from which shredded tobacco is taken up by a carding
unit and directed into a descending duct or chute. At the bottom end of the chute,
the tobacco is taken up by a toothed outfeed assembly and deposited on a conveyor
belt that carries it toward the bottom inlet end of an ascending duct or chimney.
The top end of the chimney coincides with the outfeed end of the tobacco feed and
transport unit, and is enclosed by a conveyor consisting in a looped air-permeable
aspirating belt such as will attract the tobacco, rising through the chimney as a
continuous flow of distinct particles, and cause it to form progressively into a continuous
stream.
[0003] The stream of tobacco forming thus externally of the chimney is directed by the aspirating
belt loop toward an ecreteur, or trimming station, of which the function is to reduce
the stream of tobacco to prescribed and uniform cross sectional proportions. The trimmed
tobacco stream is then released by the aspirating belt to the entry point of a station
where a continuous cigarette rod is formed.
[0004] The carding unit consists typically in a carding drum of which the surface of revolution
presents a plurality of pins serving to take up and pick the shredded tobacco.
[0005] In addition, the toothed outfeed assembly at the bottom end of the chute comprises
a further carding roller and an impeller roller, both presenting a pinned surface
of revolution.
[0006] Finally, it is also the practice to use further rollers, structurally similar to
those mentioned above, as a means of advancing the tobacco through the feed and transport
unit.
[0007] The interaction between the pins and the compact mass of tobacco can result in a
partial breakage of the pins, or even in their complete detachment from the roller.
Any fragmented or whole pins separated from the roller will find their way into the
mass of tobacco and must then be removed by procedures familiar to a person skilled
in the art.
[0008] Moreover, the properties of tobacco transported by rollers with missing or damaged
pins will be of a lower grade than those of tobacco transported by rollers with all
pins intact, and this can affect the quality of the cigarettes ultimately.
[0009] To verify possible degradation of the rollers in tobacco feed and transport units
of conventional embodiment, the machine must be stripped down and the pins examined
visually one by one to locate any that may be broken or missing. It follows that the
cigarette maker must necessarily remain idle for an extended period while the inspection
is conducted, and that production will be lost as a result.
[0010] The object of the present invention is to provide a tobacco feed and transport unit
in a machine for manufacturing tobacco products, such as will be unaffected by the
aforementioned drawbacks.
[0011] One object of the invention, in particular, is to provide a tobacco feed and transport
system that will allow damaged or unseated carding pins to be located swiftly and
easily.
[0012] The stated objects are duly realized according to the invention, with the adoption
of a tobacco feed and transport unit in a machine for manufacturing tobacco products,
of which the characterizing features are as recited in claim 1 appended.
[0013] The invention will now be described in detail, by way of example, with the aid of
the accompanying drawings, in which:
- figure 1 shows a portion of a cigarette maker, viewed schematically in perspective
and cut away in part, comprising a tobacco feed and transport unit embodied according
to the present invention;
- figure 2 shows a detail of the unit in figure 1, viewed in perspective;
- figure 3 shows the detail of figure 2, enlarged and in a longitudinal section.
[0014] With reference to figure 1, which shows an infeed portion of a cigarette maker, the
infeed portion is denoted 1 in its entirety and comprises a tobacco feed and transport
unit 2 serving to transform a mass of shredded tobacco into a continuous flow of tobacco
particles.
[0015] The components of the feed and transport unit 2 are housed in a vertically extending
enclosure 3 delimited uppermost by a horizontal wall 4 and on either side by two vertical
walls 5 and 6.
[0016] The infeed portion 1 presents an inlet duct 7 extending upward from the horizontal
wall 4, and below the duct, internally of the enclosure 3, a power driven toothed
roller 8 by which the shredded tobacco 9 is directed down into a lower chamber 10
delimited at the bottom by a conveyor belt 11.
[0017] The chamber 10 accommodates a carding drum, or roller 12, rotatable about an axis
12a transverse to the two side walls 5 and 6, which forms part of a carding unit 13
and occupies a position adjacent to the downstream end of the belt 11.
[0018] In addition to the carding roller 12, the unit 13 comprises a proportioning roller
14 set in rotation substantially tangential to the carding roller 12 and in the same
direction.
[0019] With this arrangement, the shredded tobacco 9 is directed by the toothed roller 8
onto the belt 11 and then toward the carding roller 12, whereupon a layer of the shredded
tobacco 9 substantially equal in thickness to the radial dimension of the carding
teeth is transferred by the roller 12 away from the chamber 10 and beyond its position
tangential to the proportioning roller 14.
[0020] Also associated with the carding unit 13 is an impeller roller 15 rotatable about
an axis parallel to the axis 12a of the carding roller 12, of which the function is
to take up the layer of tobacco 3 from this same roller 12 and shower the constituent
particles, in the direction denoted F1, down into a substantially vertical descending
duct or chute 16 delimited by a pair of transverse walls 17 and 18 extending parallel
one with another and with the axis 12a of the carding roller 12.
[0021] The bottom end of the chute 16 is located facing the periphery of a take-up assembly
19 comprising a take-up roller 20, functioning also as a carding or picking roller,
and an impeller roller 21 combining with the take-up roller 20 to transfer the shredded
tobacco 9 away from the chute 16.
[0022] The take-up roller 20 rotates about an axis 20a parallel to the axis 12a of the carding
roller 12, and is designed to project the tobacco 9 in the form of distinct particles
onto a transfer belt 22 moving from right to left as seen in figure 1, and angled
upward with the runout end located beneath the inlet of an ascending duct or chimney
23.
[0023] The top outlet end 24 of the chimney 23 connects with a unit 25 by means of which
to form at least one continuous stream 26 of tobacco 9, or in the case of a machine
with two tobacco rod processing lines as in the example of figure 1, with a unit 25
forming two such continuous streams 26.
[0024] The stream 26 of tobacco 9 is advanced toward a garniture assembly, not illustrated,
by which it will be formed into a continuous cigarette rod.
[0025] All the aforementioned rollers 8, 12, 14, 15, 20 and 21 of the unit 2 serving to
feed and transport the tobacco 9 are typified by the same structure. Each one of the
rollers 8, 12, 14, 15, 20 and 21, referred to generically hereinafter as a transport
roller 27 and illustrated in figures 2 and 3, is rotatable about a relative longitudinal
axis 27a and presents a plurality of pins 28 occupying the peripheral surface 29.
[0026] The pins 28 are oriented radially away from the longitudinal axis 27a of the roller
27, in such a way that the tobacco 9 will be taken up and carried along a predetermined
path extending from the inlet duct 7 toward the unit 25 by which the stream 26 of
tobacco 9 is formed.
[0027] Whilst the rollers 8, 12, 14, 15, 20 and 21 in the example illustrated are structurally
similar one to another, the transported tobacco particles will vary in size, and accordingly,
the axial and circumferential spacing of the pins 28, hence their density, are selected
on the basis of the type and condition of the tobacco 9 handled at each stage along
the predetermined path.
[0028] To advantage, the feed and transport unit 2 also comprises at least one sensing device
30 serving to verify the presence and/or integrity of the pins 28 associated with
at least one transport roller 27 of the unit 2.
[0029] Preferably, each of the rollers 8, 12, 14, 15, 20 and 21 illustrated in figure 1
is equipped with a respective sensing device 30 serving to verify the integrity of
the respective pins 28. To illustrate the structure of the unit 2 more clearly, figure
1 indicates one such sensing device 30 associated with the drum or roller 12 of the
carding unit 13, and another device 30 associated with the take-up roller 20.
[0030] The pins 28 are fashioned in conventional manner from ferromagnetic material and,
in a preferred embodiment, the sensing device 30 will comprise at least one inductive
sensor 31. Positioned in close proximity to the pins 28, the inductive sensor 31 is
able to pick up the magnetic field generated by the selfsame pins 28 and to detect
any change in the strength of the field occasioned by the absence or degradation of
one or more pins.
[0031] With reference to figures 2 and 3, which show the generic transport roller 27, the
device 30 includes at least one sensing unit 32 presenting a plurality of sensors
31 arrayed in closed order one alongside another and positioned facing the pins 28
of the roller 27. The sensing unit 32 occupies a fixed position, and is placed so
that the pins 28 will pass beneath the sensors 31 when the roller 27 is set in rotation.
[0032] In the case of an appreciably long roller 27, the device 30 will incorporate a plurality
of sensing units 32 arrayed in closed order one beside another along the longitudinal
dimension of the roller 27 and preferably staggered in the circumferential direction,
as illustrated in figure 2.
[0033] Each sensing unit 32 extends partially around the circumference of the respective
roller 27.
[0034] The pins 28 are arranged typically in a plurality of rows 28a, each passing around
the circumference of the roller 27. The rows 28a of pins 28 in turn are ordered one
beside another along the axis 27a of the roller 27.
[0035] Advantageously, to enable an exact identification of the damaged or missing pin or
pins 28, each of the sensors 31 belonging to a given sensing unit 32 is placed over
just one respective circumferential row 28a, so as to maximize its sensitivity to
the magnetic field generated by the pins 28 of the row in question.
[0036] Moreover, to ensure the magnetic effect induced by a row 28a of pins 28 is suitably
isolated from the sensor 31 monitoring an adjacent row 28a, the face 33 of the sensing
unit 32 directed toward the pins 28 will present a plurality of grooves 34, one for
each sensor 31, in which the tips presented by the pins 28 of the respective rows
28a are freely insertable (figure 3) during the rotation of the roller 27.
[0037] In an alternative version of the device 30, not illustrated in detail, the sensors
31 of a single unit 32 are ordered in ranks lying parallel to the axis 27a of the
respective roller 27, and columns extending transversely to the axis 27a. Each column
of sensors 28 coincides with a relative groove 34 in which a corresponding circumferential
row 28a of pins 28 is freely insertable during the rotation of the roller.
[0038] The sensors 31 are connected to a processing unit (not illustrated) integrated, for
example, into the master controller of the cigarette maker. The unit in question monitors
the signals received from the sensors and, in the event of a break in continuity being
detected, trips an alarm output signal that will also pilot the feed and transport
unit 2 to shut down automatically and indicate the position of the missing or damaged
pin.
[0039] It thus remains only for the operator to replace the missing or damaged pin 28, already
identified by the machine, without the need to search through the multitude of pins
presented by the roller 27.
[0040] The objects stated at the outset are realized in a unit according to the invention,
and the problems associated with the prior art duly overcome, since the breakage of
a pin can be detected in real time and the damaged or missing pin replaced swiftly,
stopping the machine only for the time necessary to effect the replacement.
[0041] Self-evidently, it will be preferable to fit the sensing device 30 to all the rollers
of the machine or, where there are cost constraints, at least to those rollers with
the more slender pins.
1. A tobacco feed and transport unit in a machine for manufacturing tobacco products,
comprising at least one transport roller (27) set in rotation about a respective longitudinal
axis (27a), presenting a plurality of pins (28) positioned on a peripheral surface
(29) of revolution and oriented radially away from the longitudinal axis (27a) in
such a way that tobacco (9) can be taken up and advanced along a predetermined path
toward a unit (25) by which it is formed into at least one continuous stream (26),
characterized
in that it is equipped with at least one sensing device (30) serving to verify the presence
and/or the integrity of the pins (28).
2. A unit as in claim 1, wherein the pins (28) are fashioned from ferromagnetic material
and the at least one sensing device (30) comprises at least one inductive sensor (31)
able to detect a change in magnetic field, placed in close proximity to the pins (28).
3. A unit as in claim 1 or 2, wherein the sensing device (30) includes at least one sensing
unit (32) that presents a plurality of sensors (31) arrayed in close order one alongside
another and facing the pins (28) of the at least one roller (27).
4. A unit as in claim 3, wherein the at least one sensing unit (32) occupies a fixed
position, with the pins (28) riding under the sensors (31) during the rotation of
the at least one roller (27).
5. A unit as in claim 3, wherein the at least one sensing unit (32) extends partially
around the at least one roller (27).
6. A unit as in claim 3 or 4, wherein the pins (28) are arranged as a plurality of single
rows (28a), extending each around the circumference of the roller (27) and ordered
one beside another along the axis (27a) of the selfsame roller, and each sensor (31)
of the at least one sensing unit (32) is positioned over one of the rows (28a) of
pins (28).
7. A unit as in claims 3 to 6, wherein the at least one sensing unit (32) presents a
face (33) directed toward the pins (28) and furnished with a plurality of grooves
(34), each circumferential row (28a) of pins (28) riding within a respective groove
(34) when set in rotation.
8. A unit as in claims 3 to 7, comprising a plurality of sensing units (32) arranged
one beside another along the longitudinal dimension of the at least one roller (27).
9. A unit as in claim 8, wherein the single units of the plurality of sensing units (32)
are staggered along the circumferential dimension of the at least one roller (27).