Patent Application
20120325884
The invention relates to the technical sector of automatic machines which operate on a strip of paper unwound from a reel.
The above-cited automatic machines comprise machines which have an unwinding station, from which the strip is guided to form a first loop buffer and then is fed towards a printing station, where at least a side of the strip is printed upon.
Normally the printing is organised according to a traditional page-setting with a standard format, for example A4 type, so that there will be a plurality of pages flanked according to the width of the strip, for example two or three, and a corresponding number of lines of pages along the development of the strip.
There is for this reason a need to separate each longitudinal line of pages from the ones flanked thereto and, thereafter, to separate the consecutive pages of each line, such as to perform subsequent operations, such as formations of collected stacks and packing thereof into envelopes.
For this reason, downstream of the printing station a first station is provided for longitudinal cutting, in which the longitudinal separation of the lines is performed, possibly together with a trimming operation; the organs of the first station operate with a continuous advancement of the strip.
The flanked strips in outlet are first guided to form relative second loop buffers and are then subjected to progressive deviation, in transversal directions, such that one is brought to above another, before entering, in this configuration, a second station for transversal cutting, provided further downstream.
The formation of the second loop buffers is made necessary both in order to unload the longitudinal tension from the lines before operating the lateral deviation on them, and also because the organs of the second cutting station operate with a step-advancement.
The lateral deviation of the lines, necessary for their superposing, inevitably generates asymmetric transversal tension in the paper (which is not extensible) that tend to cause the strips to swerve, which not uncommonly results in their tearing, with all the drawbacks connected to resetting the line.
The above drawback is more likely to occur when using light paper reels, with weight of 60 gr/m2 instead of the traditional 80 gr/m2.
The intermittent advancing of the strips can be differentiated according to the storing program between the pages of the various lines; if the stack to be formed is not an exact multiple of the number of lines present in the strip, one or the other line in inlet to the cutting station has to be selectively halted, possibly both in turn, such that only the pages destined thereto reach the store where the stack is formed, downstream of the cutters.
This situation can increase the stress forces on the strips and increase the possibility of tearing occurring.
The above-described conditions impose rather low working speeds, which negatively impact on production costs.
The aim of the present invention is therefore to provide a device and a method for supplying continuous strips to a transversal cutting station of the strips, which is designed such as to prevent the above transversal stresses from inducing paper tearing.
A still further aim of the invention relates to the desire to provide a device which, in accordance with the actuation of the method, is conformed such as to guarantee a regular functioning also in the presence of differentiated advancement of the strips.
A further aim of the invention is to provide a device based on a simple concept, which is not large in volume and is relatively inexpensive.
The above-indicated aims are attained by a device for feeding continuous strips to a transversal cutting station of the strips, which strips are supplied flanked on an arrival line, which comprises:
a basin, associated to a terminal part of the arrival line, designed to interrupt a continuity of a support plane on which the strips rest, such that each of the strips forms, by gravity, a free loop in a downwards direction in the basin;
deviator organs, located downstream of the basin, destined to guide each of the strips in order arrange the strip with a transversal orientation with respect to the arrival line, which a strip is horizontally centred with respect to the other strips and directed towards the transversal cutting station.
The invention also concerns a method for supplying the continuous strips to a transversal cutting station of the strips, the strips being supplied flanked on an arrival line, which comprises:
definition in each strip along the arrival line of a free loop trajectory orientated by gravity in a downwards direction;
guided deviation of each strip downstream of the loop for arranging each strip with a transversal orientation that is predetermined with respect to the arrival line in such that each strip is centred horizontally with respect to the other strips and directed towards a corresponding infeed of the transversal cutting station.
With the device, designed to actuate the method, the operations which switch the strips from flanked to superposed, at a predetermined distance from one another, such as to enter the transversal cutting station, are performed without any anomalous and asymmetrical transversal tensions arising; in this way uncontrolled swerving of the strips is avoided, as well as tearing of the strips.
The device and the method of the present invention thus make it possible also to use lightweight paper, in the order of 60 gr/m2, without any problems arising; indeed it is possible to considerably increase operating velocity with respect to traditional systems, by more than 50%.
The simplicity of the method and consequently of the device actuating it guarantee regular functioning even in the presence of a differentiated advancement of the strips.
Other important positive aspects derive from the fact that the device, thanks to its simplicity, exhibits limited contents and costs.
The following description relates to a preferred embodiment of the device as well as preferred actuation forms of the method, in accordance with what is set out in the claims and with the aid of the accompanying figures of the drawings, in which:
With reference to figures from 1 to 4, 100 denotes in its entirety a preferred embodiment of the device of the invention, in accordance with a first preferred embodiment of the method, schematically illustrated in
According to a known technique, at least two strips 1, 2, originating from a single reel, not illustrated, and from a preceding longitudinal cutting station, described in the preamble hereto (also not illustrated), are supplied flanked on an arrival line L.
The first embodiment of the method comprises:
definition in each strip 1, 2 along the arrival line L of a free loop trajectory orientated by gravity in a downwards direction;
guided deviation of each strip downstream of the loop for arranging each strip with a transversal orientation that is predetermined with respect to the arrival line L in such that each strip is centred horizontally with respect to the other strips and directed towards a corresponding infeed of the transversal cutting station.
An aerodynamic action is imposed on the free loops A1, A2, such as to push them downwards.
A depression is preferably generated in the zone underlying the loops A1, A2, such that the atmospheric pressure, insisting on the upper, gives rise to the downwards pushing action.
Alternatively, the same action can be obtained by injecting compressed air directed from above in a downwards direction, in the upper zone of the loops A1, A2.
The deviation is performed on the same side for both strips 1, 2, with an angle of 90° with respect to the arrival line L.
The method further comprises the strips 1, 2 being arranged vertically staggered in the tract preceding the entry thereof in the transversal cutting direction SR, in accordance with the positions of the relative inlet channel C1, C2.
The device 100 for actuating the described first embodiment of the method comprises, amongst other things:
a basin 3, associated to a terminal part of the arrival line L, designed to interrupt a continuity of a support plane on which the strips 1, 2 rest, such that each of the strips 1, 2 forms, by gravity, a free loop A1, A2 in a downwards direction in the basin 3;
deviator organs 4, located downstream of the basin 3, destined to guide each of the strips 1, 2 in order arrange the strip with a transversal orientation with respect to the arrival line L, which a strip is horizontally centred with respect to the other strips 1, 2 and directed towards the transversal cutting station SR.
Elastic means 30 are provided in the inlet zone to the basin 3, destined to act on the strips 1, 2 such as to direct them downwards internally of the basin 3 (
Air means 6 are associated to the basin 3, destined to act on the free loops A1, A2 in order to push them downwards.
In a preferred embodiment, the air means 6 are positioned on the bottom of the basin 3 (see in particular
Alternatively, the air means 6 are compressed-air type and comprise nozzles (not illustrated) positioned in the upper zone of the loops A1, A2 and orientated such that the air jet is facing downwards, towards the loops A1, A2.
The deviator organs 4 are constituted, for each strip 1, 2 by a rounded element 41, 42, arranged at 45° and destined to receive, on the external surface thereof, in sliding adherence, the respective strip 1, 2 which thus changes exit direction by 90° with respect to the infeed direction.
In the method, the rounded elements 41, 42 are both inclined in the same way such as to orientate the outlet branches of the strips 1, 2 on a same side (
Guide means 5 are provided downstream of the rounded elements 41, 42, which guide means 5 are destined to distance the strips 1, 2 by a predetermined amount in terms of height up to a predetermined amount, in accordance with the positions of the relative inlet channels C1, C2 in the transversal cutting station SR.
The guide means 5 comprise, for each strip 1, 2, an alignment roller 51, 52 associated to a sliding plane 53, 54 (
Differently from the first embodiment, the deviation of each strip 1,2 is, in this case, performed on the opposite side, with an angle of 90° with respect to the direction of the arrival line L.
The strip 1, 2, which is centred horizontally with respect to the other, but directed in the opposite direction with respect to the transversal cutting station SR, is subsequently guided to perform a 180° inversion such as to maintain the centring and be directed towards the cutting station SR too.
The inversion by 180° is suitably calibrated such as to obtain the desired vertical staggering of the strips 1, 2, in accordance with the position of the inlet channels C1, C2.
The conformation of the device 100 and the described modalities, according to which the device 100 brings the strips 1, 2 from flanked to superposed, without subjecting the strips 1, 2 to anomalous transversal stresses, enable elimination of the second loop buffers, provided downstream of the longitudinal cutting station for longitudinal cutting in the prior art solutions in the preamble.
The longitudinal cutting station of the strips 1, 2, denoted in
This configuration enables the overall size of the line to be considerably reduced.
The above is intended to be by way of non-limiting example, and any eventual modifications of detail are considered henceforth to fall within the ambit of protection defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| BO2010A 000164 | Mar 2010 | IT | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB2011/051062 | 3/14/2011 | WO | 00 | 8/24/2012 |
