CONVERTING MACHINE WITH MATERIAL STRIP STORAGE BUFFER

The present invention relates to a converting machine, i.e., a machine for winding or unwinding a strip of material on coils, particularly configured to process a delicate material. In particular, the invention is directed to a machine (1) for converting coils of a material into smaller coils, wherein the strip (N) is moved along a path (P), comprising a loading unit (2) of a strip (N) of material into the machine (1), an accumulation unit (3) of the strip (N) being processed, and a winding unit (4) of the strip (N) on a winding shaft (5, 5′) to form respective coils (B), said units being positioned along said path (P), characterized in that the accumulation unit (3) comprises:          a first movable supporting structure (20) for a first series of movable rollers (21) and a second movable supporting structure (20′) for a second series of movable rollers (21′), wherein each series of movable rollers (21, 21′) comprises a plurality of rollers aligned vertically in a plane parallel to a first and second straight path stretch (Pv1, Pv2), said first and second straight path stretches (Pv1, Pv2) being connected by a third upper path stretch (Ps), to form as a whole a substantially π-shaped path stretch (P), which encloses said movable supporting structures (20, 20′) underneath, and wherein said first and second movable supporting structures (20, 20′) slide in opposite directions away from each other between a retracted position, in which the movable rollers (21, 21′) are not in contact with the strip (N), and a plurality of extended positions, in which the movable rollers (21, 21′) are in contact with the strip (N);           a first series of fixed rollers (19) and a second series of fixed rollers (19′), facing the first and second series of movable rollers (21, 21′), respectively, but staggered vertically with respect thereto, each series of fixed rollers (19, 19′) comprising a plurality of vertically aligned rollers, respectively, on a plane parallel to said first (Pv1) and second (Pv2) stretches of path (P) and facing one side of said path stretches (Pv1, Pv2) opposite to said first and second series of movable rollers (21, 21′), i.e., on the outside of the π-shaped path stretch (P) so that said path stretches (Pv1, Pv2) are placed between said fixed rollers (19, 19′) and said movable rollers (21, 21′).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Italian Patent Application No. 102022000014725, filed on Jul. 13, 2022, the entire contents of which are hereby incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to a converting machine, i.e., a machine for winding or unwinding a strip of material on coils, particularly configured to process a delicate material.

BACKGROUND ART

The field of converting relates to all machines performing a process of winding and unwinding a strip of material onto and from coils. Such machines perform the function of transporting the strip between one coil and another of generally different sizes in a fast and defect-free manner.

Such converting operations can consist in i) producing coils of small widths and diameters from parent coils produced in large sizes for reasons of process economy; ii) processing the material to add certain features, such as printing, lamination, or film deposition; and iii) rewinding a previously produced coil to eliminate defects.

The end product of the process is an intermediate step in the processing chains of all materials, such as paper, plastics, aluminum, and laminates, made in the form of films, generally of a thickness between a few microns and one millimeter. Converting machines are used in multiple industrial fields, including the food packaging and automotive industries, for example.

However, in some application fields, a highly delicate and/or brittle, very thin and/or loosely cohesive, and thus easily flaky, material needs to be subjected to converting. In these cases, managing the converting activity can be problematic and negatively affect the operational speed of the entire process.

When the strip to be converted consists of such a material, the processing thereof should normally include special precautions to avoid the strip from breaking, which would cause the system to stop. A particularly critical step is at the start of processing, when a new coil of material, usually a large one, is to be fed into the converting machine which will reduce it into smaller coils. This step is difficult to automate because the strip could be subjected to unacceptable rips and tears. This all results in slowing down the production process and the need for more labor resulting in higher production costs.

When the converting machine also comprises a section acting as a storage buffer for the strip being processed (so as to obviate any downstream downtime), another critical step is the operation of the buffer section during the initial step of loading the strip being processed into the machine, in particular when the moving strip comes into contact with non-moving parts. Indeed, in such cases there may be a risk of strip breakage or tearing.

The need is thus felt to provide a machine for converting coils of delicate and/or brittle material which preserves high productivity and minimizes possible interruptions caused by material breakage.

SUMMARY OF THE INVENTION

Such a problem is solved by a machine for converting coils of delicate and/or brittle material as defined in the appended claims, the definitions of which are an integral part of the present description.

In particular, the invention relates to:1) a machine for converting coils of a material into smaller coils, wherein the strip is moved along a path, comprising a loading unit of a strip of material into the machine, an accumulation unit of the strip being processed, and a winding unit of the strip on a winding shaft to form respective coils, said units being positioned along said path, characterized in that the accumulation unit comprises:a first movable supporting structure for a first series of movable rollers and a second movable supporting structure for a second series of movable rollers, wherein each series of movable rollers comprises a plurality of vertically aligned rollers in a plane parallel to a first and a second straight path stretch, said first and second straight path stretches being connected by a third upper path stretch, to form as a whole a substantially π-shaped path stretch, which encloses said movable supporting structures underneath, and where said first and second movable supporting structures slide in opposite directions away from each other between a retracted position, in which the movable rollers are not in contact with the strip, and a plurality of extended positions, in which the movable rollers are in contact with the strip;a first series of fixed rollers and a second series of fixed rollers, facing the first and second series of movable rollers, respectively, but staggered vertically with respect thereto, each series of fixed rollers comprising a plurality of vertically aligned rollers on a plane parallel to said first and second path stretches, respectively, and facing one side of said path stretches opposite to said first and second series of movable rollers, i.e., on the outside of the π-shaped path stretch, so that said path stretches are placed between said fixed rollers and said movable rollers;2) a machine according to 1), wherein the path is defined by a plurality of idle toothed wheels and at least one motorized toothed wheel;3) a machine according to 1) or 2), wherein the fixed rollers and the movable rollers are idle and are vertically spaced apart by the same spacing, and wherein the fixed rollers are vertically offset with respect to the movable rollers so that when the latter are placed in an extended position, they fit between two fixed rollers without interfering therewith;4) a machine according to any one of 1 to 3, wherein the accumulation unit comprises a launching system of the fixed rollers and a launching system of the movable rollers, wherein the launching systems are configured to cause said rollers to take, during the step of loading the strip, a tangential velocity substantially equal to the sliding velocity of the strip along the path;5) a machine according to 4), wherein the launching system of the fixed rollers comprises a belt system coupled to respective pulleys and set in counterclockwise rotation by a motor drive, wherein each of the belts of the belt system unwinds along a vertical plane in tangency with small wheels of all fixed rollers of the first and second series, respectively, the belt system being connected to actuators which translate it horizontally away from the small wheels, so that the fixed rollers, once launched at the appropriate tangential velocity, return to move idle until they come into contact with the strip;6) a machine according to 4) or 5), wherein the launching system of the movable rollers comprises a belt system coupled to respective pulleys and set in clockwise rotation by a motor drive, wherein each belt of the belt system unwinds along a vertical plane in tangency with all movable rollers of the first and second series, respectively, when they are in a retracted condition;7) a machine according to any one of 1) to 6), wherein both the fixed rollers and the movable rollers comprise a surface made of elastic material, typically rubber, so as to come into contact with the strip without causing damage thereto;8) a machine according to any one of 1) to 7), wherein the accumulation unit comprises a first and a second panel, said panels being arranged facing each other so as to enclose therebetween said first movable supporting structure and said second movable supporting structure, wherein each of the movable supporting structures comprises a pair of comb-shaped supports arranged parallel to each other and to the respective panels and each comprising a plurality of horizontal arms, wherein the horizontal arms of the first pair of comb-shaped supports face the first straight stretch of the path and the horizontal arms of the second pair of comb-shaped supports face the second straight stretch of the path, and wherein each movable roller of the first movable supporting structure is supported in an idle manner by means of pins at the distal end of a pair of horizontal arms which extends from the respective pair of comb-shaped supports, and each movable roller of the second movable supporting structure is supported in an idle manner by means of pins at the distal end of a pair of horizontal arms which extends from the respective pair of comb-shaped supports;9) a machine according to 8), wherein:the spacing between the two comb-shaped supports of the first supporting structure is greater than the spacing between the two comb-shaped supports of the second supporting structure, so that, when said supporting structures slide in opposite directions, they do not interfere with each other, and whereinthe first and second movable supporting structures are vertically offset by a distance such that all the horizontal arms, but one an end arm, are on the same horizontal plane;10) a machine according to any one of 1) to 9), wherein the strip loading unit of the strip comprises an accompanying system for the strip from the loading unit to the winding unit, said accompanying system consisting of a double chain, comprising a first chain and a second chain and an accompanying bar either made of or comprising parts made of ferromagnetic material, the accompanying bar being driven by said first and second chains, wherein the double chain develops in a loop along a path and wherein the accompanying bar is movable along the loop-shaped path and is configured to drive the strip from the loading unit to the winding unit and then, after releasing the strip, to return to the starting point in the loading unit; and wherein the accompanying system further comprises a non-motorized magnetic bar, which slides idly along the path and is configured to be coupled to the accompanying bar during the operational steps of the method for loading a new strip.

Further features and advantages of the present invention will become more apparent from the description of some exemplary embodiments thereof, given below by way of non-limiting indication, with reference to the enclosed figures.

DETAILED DESCRIPTION OF THE INVENTION

The converting machine according to the invention, indicated by reference numeral1as a whole, comprises a loading unit2of the strip N of material, an accumulation unit3of the strip N being processed, and a winding unit4of the strip N on a winding shaft5′ to form respective coils B.

As mentioned above, the step of inserting the strip N into machine1is a critical step and requires special precautions to be carried out automatically.

The loading unit2of the strip N comprises the accompanying system6for the strip N along the various working steps of the machine1, i.e., from the loading unit2to the accumulation unit3and the winding unit4. The accompanying system6, shown inFIG.1with a dotted line, consists of a double chain7(diagrammatically shown in the figures with a single line) which develops in a loop along a path P defined by a plurality of idle toothed wheels8and at least one motorized toothed wheel8′. The double chain7movably supports an accompanying bar9, which is thus movable along the loop-shaped path P and is configured to drive the strip N to be loaded into the machine1from the loading unit2to the winding unit4and then, after releasing the strip N, to return to the starting point in the loading unit2.

The accompanying bar9is preferably cylindrical in shape, i.e., it has a circular section or at least comprises a surface with an arc-of-a-circle-shaped section facing the sliding direction of the double chain7. The accompanying bar9is also made of, or comprises parts made of, a ferromagnetic material so as to be subjected to attraction by a magnet.

As shown inFIGS.2-11, the accompanying system6also comprises a non-motorized magnetic bar10, which idly slides along the path P on appropriate guides. A C-shaped element10a, having a cross-section with a concave profile, is associated with the magnetic bar in order to be coupled to the accompanying bar9during the operational steps of the method of loading a new strip N.

In a resting condition, the magnetic bar10is housed in a locking-unlocking device11, from which it is picked, during the step of loading strip N, by the accompanying bar9, so as to be pushed along the path P, as will be described below.

In a first step of loading a new strip N, the strip N from a large coil upstream (not shown) is fed to the loading unit2of the machine1by means of a conveyor T and falls vertically, as shown inFIGS.2and3, positioning itself in the space between the accompanying bar9and the magnetic bar10.

FIGS.4and5show the next step, in which the double chain7is set in motion along the direction of the arrow, so that the accompanying bar9comes into contact with an end portion of the strip N until it is sandwiched between the accompanying bar9and the C-shaped element10aof the magnetic bar10. The magnetic attraction between the magnetic bar10and the accompanying bar9allows holding the strip N firmly close to one end thereof and leading it along the path P in a gentle manner, i.e., without the use of gripper systems which would damage the strip N and cause it to break.

When the accompanying bar9is in the position inFIG.5, the movement thereof along the path P causes the magnetic bar10to be unlocked by the locking-unlocking device11, as will be described below, whereby the accompanying bar9-magnetic bar10assembly together with the strip N continues to travel along said path P, as shown inFIG.6. In practice, the strip N is driven by the accompanying bar9and the magnetic bar10through the accumulation unit3(which will be described below), then into the winding unit4, where the end portion of the strip N is separated from the rest of the strip N, which then begins to be wound on a winding shaft5,5′, thus performing the converting operation. The bars9,10, associated with the piece S of strip N, continue along the path P until they return to the loading unit2, as shown inFIG.7.

The accompanying bar9continues the motion thereof until it reaches the locking-unlocking device11. The locking-unlocking device11of the magnetic bar10comprises a lever element12comprising a body12a, from a first end of which a locking finger12bprotrudes, arranged along an axis X inclined at an angle less than 90° with respect to the longitudinal axis Y of the body12a. The body12ais hinged, at a midpoint, on the hinge13, while at the second end opposite to that on which the locking finger12bis placed, the body12ais fixed to a first end of an elastic element14, the second end of which is fixed to a supporting element15of the locking-unlocking device11. The lever element12can thus pivot between an unlocking position (FIG.8) and a locking position (FIG.9) of the magnetic bar10, in which the lever element12is returned to the locking position by the elastic recall of the elastic element14.

The elastic element14, as shown in the figures, can be a conventional coil spring.

The supporting element15is adjustable along an axis Q incident with the longitudinal axis Y of the lever element12so as to adjust the tensioning of the elastic element14. For that purpose, the supporting element15comprises an adjustment screw16coaxial to the axis Q, inserted into a threaded sleeve18coupled to a hole made in the supporting element15, the adjustment screw16ending inside the supporting element15with a distal end16abeing on a fixed pin17. Since the screwing or unscrewing of the adjustment screw16cannot cause it to advance or retract due to the constraint with the fixed pin17, it causes the supporting element15to be displaced along the axis Q and thus the tensioning or detensioning of the elastic element14.

As shown inFIGS.8and9, the accompanying bar9pushes the magnetic bar10to abut against the locking finger12b, thus rotating the lever element12in the direction of the arrow inFIG.8. Then, when the magnetic bar10has passed the locking finger12b, the lever element12is called back to the locking position by the elastic element14, so that the locking finger12bis interposed between the magnetic bar10and the accompanying bar9.

FIG.10shows the next step of the loading operation of the strip N, in which the accompanying bar9reverses its motion, taking a retrograde motion that brings it to the initial position thereof. Once the accompanying bar has been released from the piece S of strip N (FIG.11), the loading unit2is ready for loading the strip N from a subsequent source coil. The operations inFIGS.7-11occur simultaneously with the normal operation of the converting machine1, i.e., converting the strip N from an upstream coil to smaller coils B downstream.

The accumulation unit3is placed between the loading unit2and the winding unit4of the strip N on a winding shaft5,5′. The accumulation unit3acts as a store buffer when it is necessary to replace a fully wound coil B in the winding unit4with a winding shaft5′ to be wound. Such an operation requires a temporary stop of the winding, therefore the accumulation unit3allows not interrupting the feeding of strip N from the conveyor T during such a stop.

As shown inFIGS.12and17-19, the accumulation unit3comprises a first and a second panel3a,3b, said panels3a,3bbeing arranged facing each other so as to enclose therebetween a first movable supporting structure20for a first series of movable rollers21and a second movable supporting structure20′ for a second series of movable rollers21′. Each series of movable rollers21,21′ comprises a plurality of vertically aligned rollers in a plane parallel to a first and a second straight path stretch Pv1, Pv2. Said first and second straight path stretches Pv1, Pv2are connected by a third upper path stretch Ps, to form as a whole a substantially π-shaped stretch of path P, which encloses said movable supporting structures20,20′ of the movable rollers21,21′ underneath.

Each of the movable supporting structures20,20′ comprises a pair of comb-shaped supports22,22′ arranged parallel to each other and to the respective panels3a,3band each comprising a plurality of horizontal arms26,26′, where the horizontal arms26of the first pair of comb-shaped supports22face the first straight stretch Pv1of path P and the horizontal arms26′ of the second pair of comb-shaped supports22′ face the second straight stretch Pv2of the path P.

Each movable roller21of the first movable supporting structure20is supported in an idle manner by pins27at the distal end of a pair of horizontal arms26extending from the respective pair of comb-shaped supports22. Similarly, each movable roller21′ of the second movable supporting structure20′ is supported in an idle manner by pins27at the distal end of a pair of horizontal arms26′ extending from the respective pair of comb-shaped supports22′.

The movable supporting structures20,20′ horizontally slide on appropriate shoe28(only the portion of one shoe28for the movable supporting structure20can be seen inFIG.17) by means of appropriate motorization (not shown). The movable supporting structures20,20′ are movable in a mutually opposite direction, as indicated by the arrows inFIG.12, between a retracted position, in which the movable rollers21,21′ are not in contact with the strip N, and a plurality of extended positions, in which the movable rollers21,21′ are in contact with the strip N.

As shown inFIG.18, the spacing between the two comb-shaped supports22of the first supporting structure20is greater than the spacing between the two comb-shaped supports22′ of the second supporting structure20′, so that when said supporting structures20′ slide in opposite directions, they do not interfere with each other. Moreover, as can be seen from the figures, the first and second movable supporting structures20,20′ are vertically offset by a distance such that all the horizontal arms26,26′ but one end arm26,26′ are on the same horizontal plane.

The inner surfaces of panels3a,3b, i.e., those facing each other, also support the double chain7, in particular a first panel3asupports a first chain7aof the double chain7and the related idle toothed wheels8, while the second panel3bsupports the second chain7bof the double chain7and the related idle toothed wheels8.

The accumulation unit3further comprises a first series of fixed rollers19and a second series of fixed rollers19′, facing the first and second series of movable rollers21,21′, respectively, but vertically staggered with respect thereto. Each series of fixed rollers19,19′ comprises a plurality of vertically aligned rollers, respectively, in a plane parallel to said first stretch Pv1and second stretch Pv2of the path P and facing one side of said path stretches Pv1, Pv2opposite to the first and second series of movable rollers21,21′, i.e., outside of the π-shaped path stretch P, so that said path stretches Pv1, Pv2are placed between said fixed rollers19,19′ and said movable rollers21,21′.

The fixed rollers19,19′ and movable rollers21,21′ are idle and are vertically spaced by the same spacing, where the fixed rollers19,19′ are vertically offset with respect to the movable rollers21,21′ so that when the latter are placed in an extended position, they fit between two fixed rollers19,19′ without interfering therewith.

Both the fixed rollers19,19′ and the movable rollers21,21′ preferably comprise a surface made of elastic material, typically rubber, so as to come into contact with the strip N without causing damage thereto.

The accumulation unit3further comprises a launching system23of the fixed rollers19,19′ and a launching system24of the movable rollers21,21′. The launching systems23,24have the function, in the step of loading the strip N, of causing said rollers19,19′,21,21′ to take a tangential velocity substantially equal to the sliding velocity of the strip N along the path P. This contrivance is very important when the strip N is made of a brittle, loosely cohesive, easily flaky material, since the contact of the moving strip N with the stationary (i.e., not rotating) rollers19,19′,21,21′ could easily cause the strip N to tear.

The launching system23of the fixed rollers19,19′ comprises a belt system23′ on each side of the accumulation unit3, coupled to respective pulleys and set in counterclockwise rotation by a motor drive25. Each of the two belts of the belt system23′ (only one side of the accumulation unit3is shown inFIG.13) unwinds along a vertical plane in tangency with small wheels19a,19′aof all fixed rollers19,19′ of the first and second series, respectively. The belt system23′ is connected to actuators23awhich translate it horizontally away from the small wheels19a,19′a, so that the fixed rollers19,19′, once launched at the appropriate tangential velocity, return to move idly until they come into contact with the strip N.

The launching system24of the movable rollers21,21′ comprises, in turn, on each side of the accumulation unit3, a belt system24′ coupled to respective pulleys and set in clockwise rotation by a motor drive26. Each of the two belts of the belt system24′ (only one side of the accumulation unit3is shown inFIG.13) unwinds along a vertical plane in tangency with all movable rollers21,21′ of the first and second series, respectively, when they are in the retracted condition. When the movable rollers21,21′ are brought to an extended position, the belt system24′ no longer comes into contact therewith, so that the movable rollers21,21′ return to move idly until they come into contact with the strip N.

The launching systems23,24are activated only immediately after the step of loading the strip N in the machine1, i.e., immediately before the contact of the rollers19,19′,21,21′ with the strip N, for the reason explained above. When said rollers come into contact with the strip N, the movement of the latter along path P keeps the rollers19,19′,21,21′ rotating, which as mentioned are mounted idle.

FIG.14illustrates the operational condition of the accumulation unit3during the step of loading the strip N described above. The strip N, driven by the accompanying bar9(not shown) along the path P indicated by the arrows, passes between the fixed rollers19,19′ and the movable rollers21,21′, which are stationary now.

FIG.15illustrates the next step, in which the loading of the strip N is completed, and the fixed19,19′ and movable21,21′ rollers are set in rotation by the respective launching systems23,24. The arrows indicate the rotation direction: clockwise for the movable rollers21,21′ and counterclockwise for the fixed rollers19,19′.

Finally,FIG.16illustrates the next step in which the machine1is in a normal operational condition. The movable rollers21,21′ are moved forward to an extended position, introducing themselves between two contiguous fixed rollers19,19′ and engaging the strip N so as to extend it to form meanders. The movement of the movable rollers21,21′ from the retracted position to an extended position and vice versa, as indicated by the arrows, allows modulating the total length of the path P as needed, either by lengthening it (movable rollers21,21′ in a more extended position) or shortening it (movable rollers21,21′ in a less extended position), so as to act as a storage buffer for the strip N during processing, in case of a processing stoppage or slowdown of the downstream in winding unit4.

The winding unit4comprises a rotatable disc29, which supports two winding shafts5,5′ of the coils B. In turn, the winding shafts5,5′ are rotatable by means of an appropriate motorization.

The winding unit4further comprises a feeding roller30of the strip N to a winding position.

The winding shafts5,5′ are placed in opposite positions along a diameter of the disc29, so that 180° rotation of the disc29allows taking the first winding shaft5or the second winding shaft5′ alternatively to said winding position.

The converting machine1according to the present invention thus allows the initially set objects to be achieved.

In particular, the special arrangement of launching systems for the movable rollers21,21′ of the accumulation unit3and/or the automatic loading system also allow subjecting to the converting operation strips N made of particularly delicate, loosely cohesive and/or flaky materials, while not renouncing high productivity related to the automation of the various operations.

However, it should be understood that even if an automatic loading unit as described above were to be dispensed with or completely eliminated, the accumulation unit3of the invention alone would allow the management of the converting operation without causing breakage or tearing of the strip N made of a delicate material.

It is apparent that only some particular embodiments of the present invention have been described, to which those skilled in the art will be able to make all changes required for the adaptation thereof to particular applications, without departing from the scope of protection of the present invention.