The present invention relates to a device and to a procedure for the transfer of tobacco products in batches.
The invention finds application to advantage in complete manufacturing lines for tobacco products, such as cigars, cigarettes and filter tips, and in particular for cigarettes; one typical instance, by way of example, would be the operation of directing the tobacco products in question from a maker to a packer or other wrapping machine.
In accordance with one conventional method of this type, cigarettes emerging from the maker are ordered in containers, known as trays, which will be stored in readiness before being emptied at an infeed station of the packer.
The single trays are filled by means of a hopper presenting a vertical back wall, and two fixed side walls extending divergently from top to bottom.
The aforementioned walls combine to delimit a top inlet opening in communication with a conveyor, on which tobacco products advance in a continuous flow toward the hopper, and a bottom discharge opening closed off by a movable shutter.
The hopper is emptied cyclically, whilst the flow through the inlet opening is continuous. The hopper is filled by closing off the bottom discharge opening and allowing the cigarettes received from the conveyor to accumulate inside.
To fill a tray, the hopper bottom is opened for a duration sufficient to allow the cigarettes to pass into the tray beneath, the tray also being lowered by degrees as the cigarettes are taken up.
The trays have to be filled at relatively high speed in order to keep up with the fast production tempo of the cigarette maker, and at the same time with special care, so that the cigarettes will not lose their ordered arrangement and suffer damage.
Whilst the cigarettes flow substantially non-stop from the conveyor into the hopper, the flow is not uniformly constant. Consequently, it often happens that the rate of flow is too high, with the result that the cigarettes will be compressed excessively one against another or against the hopper walls and their integrity compromised, for example through tobacco being shed from the cut ends.
Conversely, if the rate of flow drops below an optimum level, then the massed cigarettes will lack compactness and lose their orderly arrangement, possibly assuming incorrect positions one relative to another, for example wrongly oriented, with axes no longer perpendicular to the back wall of the hopper but slightly askew, or even falling into a void and bending and breaking as a result.
The object of the present invention is to provide a device and a procedure for the batch transfer of tobacco products, such as will ensure that the products are handled with extreme care during the operation of filling the aforementioned trays.
In particular, the object of the invention is to design a device and a procedure that will allow of accurately monitoring and controlling both the rate at which the cigarettes flow into the hopper, and the pressure acting on the single cigarette while in the hopper and when transferred into a tray.
A further object of the invention is to provide a device and a procedure for the batch transfer of tobacco products that will be compatible with high speed operation and allow an ordered arrangement of cigarettes massed in large quantities for loading into trays.
The stated objects are realized according to the present invention in device for the batch transfer of tobacco products of the type comprising a hopper furnished with a back wall and two side walls combining to delimit a top inlet opening through which tobacco products are admitted, and a bottom opening from which the tobacco products are discharged, also a shutter by which the bottom opening is opened or closed; the device disclosed further comprises a motion-inducing mechanism connected to the side walls, such as will actively vary the geometry of the side walls in order to adapt the internal volume of the hopper to the quantity of tobacco products admitted through the top opening.
The aforementioned objects are realized similarly in a procedure for the batch transfer of tobacco products that involves feeding a flow of such products into a hopper furnished with a back wall and two side walls combining to delimit a top inlet opening, and a bottom opening from which the tobacco products are discharged, also a shutter by which the bottom opening is opened or closed, and includes the step of actively varying the geometry of the side walls and the internal volume of the hopper, according to the quantity of tobacco products admitted, by means of a motion-inducing mechanism linked to the side walls.
The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which:
Referring to
The device 1 comprises a main conveyor 6 by which tobacco products, in this instance cigarettes 2, are carried from the cigarette maker 4 toward the packer 5 along a predetermined direction X; the conveyor 6 operates in conjunction with a unit for management of the containers 3, each of which is able to hold a plurality of cigarettes 2 arranged in ordered alignment.
The container management unit is neither shown nor described, but could be of the type disclosed in (patent application no EP 06116470.3 or application no EP 06116480.2, both filed in the name of the present applicant.
With reference in particular to
In addition, the main conveyor 6 presents an opening 12 located intermediately along its length, directly above and communicating with a hopper denoted 13.
In the preferred embodiment illustrated, the main conveyor 6 comprises a first belt 14 looped around pulleys 15, extending between the cigarette maker 4 and the hopper 13 and presenting a top branch 16 on which cigarettes 2 emerging from the maker 4 are carried, lying side by side.
A second belt 17, looped over relative pulleys 18 and aligned in the same plane as that occupied by the first belt 14, extends from the hopper 13 to the cigarette packer 5 and presents a top branch 19 carrying cigarettes 2 about to enter the packer 5. The first belt 14 and the second belt 17 present respective ends 20 and 21 positioned facing one another and combining to delimit the intermediate opening 12 aforementioned.
The hopper 13 comprises a back wall 22 and two side walls 23 delimiting a top inlet opening 24a aligned with the opening 12 in the conveyor 6.
The side walls 23 are mutually divergent, extending from the ends 20 and 21 of the belts 14 and 17 and spreading to a distance marginally less than the width of one container 3.
Each side wall 23 is also of width approximately equal to the length of one cigarette 2, so that the hopper 13 presents a bottom discharge opening 24b substantially identical in terms of outline and dimensions to the bottom 7 of the container 3. This same opening 24b can be opened or closed by a shutter 25 of conventional embodiment, comprising a plurality of retaining bars 25a set perpendicular to the back wall 22 and arrayed side by side. The bars 25a are capable of movement between an open position (
More exactly, with reference to
Numeral 29 denotes a support element located next to the hopper 13 and driven by a relative motor 30, shown schematically, of which the function is to carry and position a single container 3 during the filling cycle (FIGS. 4 to 6).
The support element 29 is traversable vertically between a first position (
With the cigarette maker 4, the packer 5 and the device 1 in operation, cigarettes 2 emerging from the packer 4 and advancing along the conveyor 6 gravitate into the hopper 13, which is closed at the bottom by the shutter 25 and will therefore fill to the point where further cigarettes 2 begin rolling over the cigarettes 2 occupying the duct 26 and pass beyond, advancing toward the packer 5. In normal operation, accordingly, part of the total flow of cigarettes 2 will fill the hopper 13 and the trays 3, and part will find its way directly into the packer 5.
Empty containers 3 are brought to the hopper 13 one at a time by the aforementioned management unit (not illustrated) in readiness for filling. To this end, the container 3 is offered to the hopper 13 with the top opening 10 directed upwards, the auxiliary opening 11 facing the hopper 13, and the bottom 7 beneath the bottom discharge opening 24b, so that the hopper 13 is effectively positioned internally of the container 3 (
Next, the hopper 13 is emptied by shifting the bars 25a of the shutter 25 to the open position so as to release the cigarettes 2, which drop through the bottom opening 24b onto the bottom 7 of the container 3; at the same time, the container 3 is lowered gradually to free more space (
When the container 3 is full, the bars 25a of the shutter 25 return to the closed position (
Also forming part of the device 1 is a motion-inducing mechanism 31 linked to the side walls 23 of the hopper 13, such as will actively vary the geometry of the selfsame side walls 23, and thus reproportion the internal volume of the hopper 13, according to the quantity of cigarettes 2 admitted.
As shown in
The variation in internal volume of the hopper 13 must be proportioned so as to avoid compression and degradation of the cigarettes 2, while at the same time ensuring the flow remains suitably compact, so that the cigarettes 2 do not lose their ordered alignment.
As illustrated in
In a preferred embodiment, the sensor 32 will be located near the conveyor 6 along the predetermined direction X followed by the cigarettes 2, above the top opening 24a of the hopper 13, so as to measure the rate of the flow.
In particular, the sensor 32 is a feeler placed to measure the depth Sp of the flow of cigarettes 2 advancing along the conveyor 6 (
The feeler 32 comprises a finger 35 of which a first end 35a is coupled to the spindle 36 of a potentiometer such as will pick up any angular movement of a floating second end 35b.
The second end 35b appears substantially flat when seen in cross section, and is thus able to ride on the cigarettes 2 without damaging them.
The potentiometer is mounted above the conveyor 6 and over a zone 37 occupied by the advancing flow of cigarettes 2, with the spindle 36 set at right angles to the back wall 22 of the hopper 13. The finger 35 is capable of movement between a first position, in which the second end 35b encroaches on the zone 37 occupied by the cigarettes 2, and a second position in which it is caused by a rise in level of the flow of cigarettes 2 to rotate through an angle α (
In the preferred embodiment illustrated in the accompanying drawings, each of the side walls 23 of the hopper 13 comprises a flexible leaf 38. A first end 38a of the leaf 38 is inserted slidably in a terminal portion 39 associated pivotably with the fixed frame 28 of the device 1 by way of an axis Y of rotation located near the top inlet opening 24a. The leaf 38 also presents a second end 38b associated pivotably with the fixed frame 28 of the device 1 by way of a further axis W located near the bottom discharge opening 24b.
The actuator 33 comprises a pair of levers 40 flanking the hopper 13, each with a first end 40a hinged to the frame 28 and a second end 40b linked to a corresponding flexible leaf 38.
The first end 40a of each lever 40 is coupled to a pivot 41 turning on an axis Z located alongside the axis Y of rotation of the terminal portion 39 aforementioned. The second end 40b of the lever 40 is linked to a middle area 42 of the respective leaf 38 by way of a connecting rod 43 coupled pivotably to the lever 40 and attached hingedly to a lug 44 associated rigidly with the leaf 38.
Each of the levers 40 is connected to a motor 45 and rendered capable thus of angular movement on the pivot 41 at its first end 40a.
The motor 45 will consist preferably in a double acting pneumatic or fluid power cylinder 46 mounted horizontally near to the inlet opening 24a of the hopper 13 (
Each rod 48 carries a pin 49 engaging a socket 50 afforded by the first end 40a of the corresponding lever 40 and distanced from the rotational axis Z of the pivot 41. Thus, a linear displacement of the rod 48 produces an angular movement of the lever 40 which, by way of the connecting rod 43, will either push or pull on the leaf 38 at the middle area 42 and cause it to arch.
More exactly, with the two rods 48 in a partially extended position, the leaves 38 remain undeformed and straight (
There now follows a description of a preferred through not exclusive transfer procedure employing the device 1 disclosed.
In operation, with the hopper 13 filling up, the control unit 34 is programmed to position the two side walls 23 according to a prescribed law of deformation “Ld” that corresponds to a reference flow rate “Pr” of the cigarettes 2 advancing on the conveyor 6. At the same time, the control unit 34 also monitors the effective flow rate “Pe” by way of the sensor 32, comparing this value with the reference value “Pr” and, should the effective rate “Pe” differ from the reference rate “Pr”, responds by adjusting the law of deformation “Ld”.
More exactly, from the moment when the bottom of the hopper 13 is closed off by the shutter 25, the cigarettes 2 begin to accumulate, rising ultimately to the level of the intermediate opening 12. During this stage, the control unit 34 is programmed to pilot the operation of the actuator 33 in such a way that the volume internally of the hopper 13 will be increased in accordance with the prescribed law of deformation “Ld” which, for example, induces a linear variation in the deflection Fr (
The law “Ld” governing the increase in volume is precomputed so that the reference flow rate “Pr” of the advancing cigarettes 2 will be sensed by the feeler 32 as constant, or rather, the flow passing beneath the feeler 32 will present a constant reference depth “Spr”.
If the effective rate of flow “Pe” sensed by the feeler 32, or the effective depth “Spe”, is not at variance with the reference value “Pr”, the control unit 34 will apply no correction to the law “Ld” governing the increase in volume.
If the effective rate of flow “Pe” sensed by the feeler is greater than the reference rate “Pr”, or the effective depth “Spe” is greater than the reference depth “Spr,” the control unit 34 will alter the law “Ld” governing the increase in volume in such a way, for example, as to speed up the rate at which the side walls 23 are deformed.
If the effective rate of flow “Pe” sensed by the feeler is less than the reference rate “Pr”, or the effective depth “Spe” is less than the reference depth “Spr,” the control unit 34 will alter the law “Ld” governing the increase in volume in such a way as to slow the rate at which the side walls 23 are deformed, for example, or to leave the walls 23 undeformed, or indeed to reduce the volume of the hopper 13 by causing the walls 23 to flex inwards.
The control unit 34 also governs the rate “Vd” at which the support element 29 descends during the step of emptying the hopper 13 and filling the container 3. The container 3 is lowered according to a prescribed law of motion “Lm” that corresponds to the reference flow rate “Pr” of the cigarettes 2 advancing on the conveyor 6. At the same time, the control unit 34 senses the effective flow rate “Pe” by way of the sensor 32, comparing this value with the reference value “Pr”, and should the effective rate “Pe” differ from the reference rate “Pr”, responds by adjusting the law of motion “Lm”.
In detail, to fill a container 3, the shutter 25 opens and the cigarettes 2 begin to drop into the container 3. During this step, the control unit 34 is programmed to pilot the speed of the motor 30 driving the support element 29 so that the element will descend subject to the predetermined law of motion “Lm” which, for example, induces a downward movement of the container 3 according to a law expressed as “Lm: S=ct+d”, where “t” is time and “c” and “d” are constants, which results in a rate of descent equal to “Vd=c”.
The law “Lm” governing the rate of descent is precomputed so that the reference flow rate “Pr” of the advancing cigarettes 2 will be sensed by the feeler 32 as constant, or rather, the flow passing beneath the feeler 32 will present a constant reference depth “Spr”.
If the effective rate of flow “Pe” sensed by the feeler 32, or the effective depth “Spe”, is not at variance with the reference value “Pr”, the control unit 34 will apply no correction to the law “Lm” governing the rate of descent.
If the effective rate of flow “Pe” sensed by the feeler is greater than the reference rate “Pr”, or the effective depth “Spe” is greater than the reference depth “Spr,” the control unit 34 will alter the law of motion “Lm” in such a way as to increase the rate Vd at which the container 3 descends.
If the effective rate of flow “Pe” sensed by the feeler is less than the reference rate “Pr”, or the effective depth “Spe” is less than the reference depth “Spr,”, the control unit 34 will alter the law of motion “Lm” in such a way as to reduce the rate Vd at which the container 3 descends.
The function of monitoring the rate of descent Vd can also be performed simultaneously with that of monitoring the deformation of the side walls 23, applying a control logic that is more complex and not described here.
In any event, all of the monitoring and control operations are intended primarily to ensure that the pressure exerted on each cigarette 2 by the other cigarettes and by the walls of the hopper 13 remains constant, so that the cigarettes will not be crushed and damaged.
Moreover, these same operations ensure that the cigarettes 2 can be kept in their proper orderly alignment, and prevented from assuming positions with axes no longer perpendicular to the back wall of the hopper, but slightly askew and at risk of bending or breaking.
Number | Date | Country | Kind |
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BO2005A000733 | Dec 2005 | IT | national |