This application is a 371 of PCT/IB2011/053548, filed Aug. 9, 2011, which claims the benefit of Italian Patent Application No. FI2010A000177, filed Aug. 10, 2010, the contents of each of which are incorporated herein by reference.
The present invention concerns the high speed packaging of folded tissues such as napkins, handkerchiefs and the like. More specifically it concerns an apparatus and method for continuously feeding such products, arranged in stacks and coming from folding machines, to packaging machines such as revolving drum machines arranged downstream.
The operation of such a kind of machines, arranged and working between the folding system and the packaging system, is very complex due to the nature of the material normally used (highly pliable tissue paper), and above all to the high working speed that is imposed.
These machines or apparatus have substantially the features described e.g. in European Patent EP537125, in the name of the same present applicant. They comprise belt or chain conveyor systems that feed single folded article from the outlet of the folding machines towards an accumulation and counting unit having the function of grouping the articles in stacks, each including a pre-settable number of pieces, controllable as needed. The accumulation and counting unit comprises a series of adjacent and mutually spaced collecting discs (variable in number depending on the size of the machine, revolving in a mutually integral fashion and provided with pockets, for collecting single folded products, the pockets being in the shape of curvilinear tangential laminations, adjacent to one another and partially superimposed, in such a way that each pocket, indeed defined by the spacing between to consecutive laminations, is adapted to house a single folded article.
The collecting discs cooperate tangentially with separating wheels revolving in a step-by-step fashion, having radially projecting blades, suitably spaced along the periphery of the wheel so that; between two consecutive ranks of adjacent blades (each rank being determined by a plurality of coplanar blades, each on a respective wheel), a housing is formed in which a group or stack of articles is accumulated. Such articles are taken by the blades from the collecting discs, following to insertion of the same blades in the space between a disc and an adjacent one.
Downstream of the accumulation and separating wheels, transportation means are adapted to withdraw the accumulated groups of articles and to convey them towards the packaging system. The transportation means, according to the known art, can adopt different arrangements, such as chain or slider arrangements.
As mentioned, the problems affecting the known apparatus essentially result from the difficulty of ensuring reliable performances in high-speed operation, as imposed by more and more demanding productive requirements. In this respect, the flexibility, speed and reliability of the known solutions are not fully satisfactory, and indeed are often the cause of production stops, in turn causing wastes of material and malfunctions of the packaging machines.
There is therefore a strong need for an integrated system for the accumulation, counting and transportation of the product from the folding machine, which is flexible, reliable, highly productive and with no restraining limits in the working speed.
The object of the present invention is therefore to provide a feeding apparatus of stacks of folded products, generally of the kind described above, that attains a constant and reliable feed of variably sized product stacks, overcoming the present limits in the working speed, with relatively simple and safe constructive solutions.
According to the invention, this object is achieved with an apparatus and method for feeding stacks of tissues or similar folded paper products towards an automatic packaging system, having the essential features defined by the attached claims.
The characteristics and advantages of the apparatus and method for feeding stacks of tissues or similar folded paper products towards an automatic packaging system according to the present invention will be apparent from the following description of embodiments thereof, made purely for exemplifying purposes and not limitative, with reference to the attached drawings wherein:
a (front and side views, respectively) to 10, 10a (front and side views, respectively) show successive formation steps of a product stack and subsequent progress towards the packaging machine downstream, with the apparatus according to the previous figures;
a and 14b show the apparatus of
Referring to the above figures, and namely to the FIG. from 1 to 12, a feeding machine or apparatus according to a first embodiment of the invention is arranged at the outlet of a folding machine (not shown, being indeed of a known kind), and comprises pairs of product supplying belts 1 feeding the product to a plurality of collecting discs 2, normally three side by side discs for each workflow channel. A set of product separating and accumulating wheels 3, two for each workflow channel according to the present example, cooperates as in the known art with the collecting discs 2, a support structure or frame 4 being provided for supporting the discs and the wheels. The depicted exemplifying embodiment is therefore an apparatus with two adjacent workflow channels or lines. Each wheel has a distribution of radial blades 31. Two mutually aligned blades of respective adjacent wheels form a blade rank, the blades in each rank being kept mutually coplanar in operation.
A system for radially ejecting the stacks from the separating wheels 3 is generally indicated at 5, and is controlled by a crank and rod control device 6 driven, on the crank, by a driving camshaft with cams 6a. A single camshaft controls the multiple side by side workflow channels (as further clarified hereafter) and designed so as to obtain a kinematic law adapted to allow the operation of the system as described further on. The device 5, as noticeable in
The crank and rod control device 6 comprises, for each rod-crank set controlling the pushing members, an unlocking system 7, useful in case of product jams as better clarified hereafter. A system for stopping the product during the formation of the stacks comprises, again for each single workflow channel, a bracket 8 and a number of stop members 9 adjustable in a longitudinal direction of the bracket, that is a direction substantially tangential with respect to the separating wheels 3 and orthogonal with the ejection direction. The stop members 9 have the function of creating, in a step of ejection of the products from the separating wheels, a containment recess 10, adjustable as a function of the number of articles in each stack. The bracket 8 is movable according to a direction parallel with the ejection direction, driven by an actuator 11, normally a pneumatic actuator, in turn adapted to allow for the product outlet in case of malfunctions, without causing jams in the system, and to be restored to running order without production stops.
In
The system 12 comprises a pair of mutually spaced chains 13, and a plurality of crosspieces 14 extending between the chains to mechanically interfere with the stacks and thus urge them along the transport directions. It is important to notice that, according to the invention, the transport system can extend axially (that is parallel with the rotation axis of the separating wheels 3) so as to convey the stacks ejected by a plurality of side by side stack forming workflow channels, like the two in the depicted example. Accordingly, multiple channels are conveyed to a single outlet channel feeding the packaging machine. The number of workflow channels coming upstream from the folding machine can vary as a function of the speed of this machine, as well as of the speed of the downstream packaging machine. Moreover, the stacks can be ejected vertically upwards, as in the presently considered example, or according to different arrangements, depending on the type of packaging machine employed, with the support of the stacks by the separating wheels 3 being in any case assisted by gravity.
Considering now again specifically the transport system, a conveyor belt 15 is operatively arrange in the space between the two chains 13, winding around deviation rollers having a reduced width, with respect to the width of the path of the chains. The belt 15 is provided with holes 16, uniformly distributed and communicated with a vacuum source (not shown) via an inner chamber 17 with slots, acting also as a support element of the belt, and a manifold 18. The belt 15 supports therefore the stacks on a top side thereof, so that they are kept in adhesion by suction to the same belt during the whole transport run towards the belts 40 directed to the packaging machine.
One can also notice a series of guides 19 and 20 extending in turn along the transport direction, for keeping the stacks tightly restrained in the proximity of the lower side, i.e. the side close to the separating wheels 3 from which the same stacks are ejected. More in detail, the guides 20 provide a lateral containment to the stacks, while the guide 19 supports the same stacks in the vertical direction when the suction ceases (the transport belt 15 ends in fact its development before the chains 13. Finally, the reference numeral 22 indicates support elements of the transport system 12.
A motor M1 drives, via a transmission 21 (
Referring now in particular to
For the time being, starting from
The separating wheels 3 have a step by step motion at a variable speed as a function of the number of articles that each stack must include. As the rotation speed varies, the period consequently varies between the insertion of a rank of separating blades 31 and the insertion of a subsequent rank between the collecting discs 2, and accordingly the number of articles accumulated between the two subsequent blade ranks varies. Such variable speed can be programmed through a numerical control system with a kinematic law that indeed provides for accelerations and decelerations of the rotation.
In particular in the step of
Considering
It is worth noting how the front face of the pushing members, contacting the product stack 30a, does not cause any deformations or withdrawals of the same stack as the member returns back to the rest position, because the radial displacement tends to compress the stacks towards the support surface of the separating wheels 3.
In the stage of
The bracket 8 and the stop members 9 have the function of setting the size of the containment recess 10 and creating an abutment for the stack under formation during the working steps in which the blades 31 are not in contact, on the downstream side, with the product stack being ejected (
Considering now the transfer of the stacks to the packaging machine, via the feeding belts 40, with reference in particular to the
It will be apparent that the coordination between the various driving systems is such that no mechanical interference occurs between the ejecting pushing members 5a and the crosspieces 14, and also that the stacks being delivered from the ejection system may interfere with the products previously ejected and being transported to the outlet to the packaging machine.
The previously ejected stacks reach then the feeding belts 40, the speed of the chains 13, of the belt 15 and of the same belts being synchronized with the motors M2, M4. As mentioned, the thrusting crosspieces 14 disengage without causing deformations to the stacks, although maintaining the maximum precision as far as the position of the stack is concerned when passing from the chains 13 to the belts 40, even at high speed. The belts 40 then provide for keeping the stack compressed and orderly during the feeding transport to the packaging machine.
The provision of a safety device in the product ejection system, for reacting to possible malfunctions and remedying thereto, has been already mentioned. With particular reference to the
At the same time, the unlocking system 7 of the ejection devices 5, essentially formed, in turn, by linear actuators arranged along the rod closet o the pivotal connection point with the crank, is activated. Accordingly, such actuators reduce the length of the rods and in this way the pushing ejection devices 5 are radially driven back, out of the ejection area so that they become out of order.
A possible jam, in order to consequently switch on the actuators, is detected through known sensor means, not shown, e.g. photo sensors.
With reference now to
The movable bracket 8′ with the stop members 9′ (visible in particular in
In this embodiment the apparatus according to the invention feeds directly a packaging drum 58′, of a type known as such, revolving in turn around an axis parallel with the rotation axes of the discs 2′ and of the wheels 3′. The drum 58′ is provided with radial pockets 59′ in which the product stacks are inserted with the interposition of a packaging film sheet 62′, as common practice in the field. The known film cutting and feeding system is not shown
In greater detail,
Then, in
The axis of the drum 58′ lies over the above mentioned central ejection plane 54′, and is in the median point, when considered along a tangential direction, with respect to the height of the product and of the containment recess 10′. The distance indicated with 55′ represents indeed the off-centering distance between the plane 54′ and the plane 53′, and corresponds to half the width, measured tangentially, of a stack containment recess 10′, the latter width being indicated with 56′ and being substantially equal to the height of a packaging pocket of the drum 58′.
In the pockets 59′ of the packaging drum 58′ extraction devices 60′ are arranged, depicted schematically and working in accordance with known techniques. The
In operation, with particular reference now to the
In this step the separating wheels 3′ reach the minimum speed as described for the previous embodiment and a product stack, here indicated with 64′, with the interposition of the film sheet 62′ has been inserted in a pocket 59′ of the packaging drum 58′.
The device 8′ (
The separating wheels 3′ keep on rotating, and the ejection device carries out an abrupt backward movement returning to the start position, without interfering with the stop members 9′; the packaging drum 58′ starts to change its position.
From
In this condition the stack 30′ being compressed is supported in the correct position, with reference to the blades, tank to a descent movement of the device 8′, and consequently of the stop members 9′, controlled via the cam 65′, designed so as to compress the stack gradually until it has the established height before the ejection. Such a mobile control is in this case necessary due to the different arrangement of the product and the consequent possible fall by gravity force. The ejection is then performed by the device 5′ substantially as in the first embodiment, with however also the stabilizing assistance of the bars 57′, keeping the stack 30′ in the correct geometry during ejection until the insertion in the packaging pocket of the drum 58′ is completed.
Also in this case the number of wheels 3′, pushing members 5a′ and stop members 9′ are variable as a function of the product to be packaged, and arranged so as not to mutually interfere (e.g. as shown in
Finally, in
Generally speaking, the construction ad operation of the ejection means 5, 5′, having according to the invention a reciprocating motion component in the radial direction, in cooperation with the stop means operating on the downstream side of the stack and that assist the complete formation and the transport of the same (such stop means being independent and adjustable with respect to the ejection means), ensure an effectiveness and a precision (stack size control) unachieved by known systems. The invention also permits to obtain a vertically oriented outlet of the product (first embodiment), with subsequent conveyance to a single transport line, for a plurality of side by side workflow channels, and an advantageous fast-actuation emergency unload in case of product jams.
The spatial references vertical/horizontal used above are clearly intended in connection with the most typical working arrangement and with the orientation shown in the figures, although it is as clear that these reference should not be considered at all as limitative.
The present invention has been described so far with reference to some preferred embodiments thereof. It will be understood that other embodiments are encompassed by the inventive scope of protection defined by the attached claims.
Number | Date | Country | Kind |
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FI2010A0177 | Aug 2010 | IT | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/IB2011/053548 | 8/9/2011 | WO | 00 | 4/9/2013 |
Publishing Document | Publishing Date | Country | Kind |
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WO2012/020374 | 2/16/2012 | WO | A |
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2461002 | Apr 1976 | DE |
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Number | Date | Country | |
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20130209215 A1 | Aug 2013 | US |