DEVICE AND METHOD FOR MOVING REELS IN AN UNWINDER

Abstract

Device for moving paper reels in an unwinder of the type in which a nearly empty reel (1) is moved along a predetermined path between more operating stations in each of which the reel (1) is free to rotate about its longitudinal axis. The device is disposed and acting between the said operating stations and comprises: a carriage (4) intended to support a nearly empty reel (1) and movable between said operating stations, the reel (1) being free to rotate about its longitudinal axis on the carriage (4); a structure (5) supporting said carriage (4); means for moving said carriage (4) between said operating stations; means for controlling said means for moving the carriage (4).

Description

The present invention relates to a device and a method for moving reels in an unwinder.

It is known that unwinders are destined to unwind a web material from a reel to supply it to one or more machines located downstream in a determined work cycle.

In a possible known conformation, an unwinder comprises a bearing structure onto which two conical supports are disposed to engage two corresponding mandrels bilaterally inserted in the central tubular nucleus of the reel, also called “core”, in such a way that the reel is free to turn about the respective axis and the free unwinding of the respective web is allowed.

An essential step during use of unwinders is the changing of the reel, that is an operation allowing replacement of a nearly empty reel with a new one. Such operation, during which the continuity of the web supply to the machines located downstream must be ensured, is most frequently carried out in an almost exclusively manual way with both the reels being stopped. Practically, the first reel, which is nearly empty, is moved away from the support cones, between which an operator, with the aid of a mechanical lifter, subsequently fits a new reel to be unwound. WO 2004/080869, WO 2004/080867, WO 2004/043827, U.S. Pat. No. 6,679,451 and EP 822912 disclose examples of mechanical unwinders in which the human intervention is reduced. In general terms, during the reel changing step, there are problems concerning the control of the tension of the paper supplied by the reel nearly empty in order to prevent excessive slackening or, on the contrary, undesired tears.

The main aim of the present invention is to solve the above mentioned drawbacks.

This result has been achieved according to the invention thanks to the idea of actuating a device and a method having the features described in independent claims. Other features of the invention are the object to the dependent claims.

Thanks to the present invention, it is possible to move the reels of paper which are finishing (nearly empty) in a controlled way, imposing to the same, during the reel change, a translation and a rotation with operating speeds apt to always assure an optimal control of the tension of the paper directed downstream. These features determines a reel changing which is more simple, more effective, more sure and also automatically operable. Moreover, a device in compliance with the present invention is of relatively simple and economic fabrication and reliable also after prolonged periods of use.

These and other advantages and characteristics of the invention will be best understood by anyone skilled in the art from a reading of the following description in conjunction with the attached drawings given as a practical exemplification of the invention, but not to be considered in a limitative sense, wherein:

FIG. 1 represents a schematic side view of an unwinder provided with a device in accordance with a first embodiment of the present invention;

FIG. 2 represents a schematic lateral view of an unwinder provided with a device in accordance with a second embodiment of the present invention;

FIG. 3 represents a modified particular of the example of FIG. 2, wherein it is shown a nearly empty reel (1) supported by a device in compliance with the present invention;

FIG. 4 is identical to FIG. 3, except for the fact that the reel (1) is not shown for a better representation of other parts of the drawing;

FIG. 5 represents a cross-sectional view in correspondence of one of two sides of the carriage, in which, for sake of simplicity, the transport chain of the carriage is not represented;

FIG. 6 represents a scheme relevant to the braking mechanism acting on the support and moving carriage of the reel nearly empty;

FIG. 7 represents a schematic perspective view in correspondence of one of two sides of the carriage;

FIG. 8 represents a simplified diagram of the control and command system;

FIG. 9 represents a schematic side view of a re-winder provided with a device in compliance with the present invention, according to another embodiment of the same;

FIG. 10 represents an enlarged particular of FIG. 9, with some parts omitted to better show other parts;

FIGS. 11A-11C schematically represent a sequence of disengagement of the cones from the mandrels applied on the core of a nearly empty reel in the station (SN).

Reduced to its essential structure and with reference to the example shown in the drawings of FIGS. 1-4, a device according to the present invention can be used in an unwinder of the type in which a reel nearly empty is transferred from a first station (SN) in which it rotates about its longitudinal axis until it is in a condition of “nearly total unwinding” (a condition in which its diameter reaches a predetermined value, smaller of the initial diameter) to a second station (SI) disposed at a predetermined distance from the first station (SN), and transferred again from said second station (SI) to a third station (SP) in which it can continue to rotate around its longitudinal axis until it is completely unwound, that is, until a new reel is placed in the first station (SN).

In the drawings, the references (1) and (2) designate, respectively, a nearly empty reel and a new reel destined to replace the nearly empty one; the reference (S) designates the unwinder.

The unwinder (S) has a supporting structure (SF) with an operating front (FO) on which there are defined, in correspondence of said first station (SN), support seats (AP) for the two axial ends of a reel (2). Such ends are formed by two conical elements (C) which can be inserted, on opposite sides, in the core (N) of the reel, said conical elements being partially projecting from the two sides of the reel and allowing the idle rotation of the reel on said support seats. Said conical elements (C) are disengaged from the core (N) of the reel before commanding the transferring from the station (SN) to the station (SI).

The structure and the functioning of an unwinder are known to the technicians working in this field and, therefore, a more detailed description is omitted.

The moving device which is the object of the present invention is disposed and acting between said stations (SI) and (SP) and it comprises:

• • means (3) for transferring a nearly empty reel (1) from said first station (SN) to said second station (SI);
  • a carriage (4) apt to support a nearly empty reel (1) and movable between said second station (SI) and said third station (SP);
  • a structure (5) for supporting said carriage (4);
  • means for moving said carriage (4) between said second station (SI) and said third station (SP);
  • means for controlling said transferring means (3) and said carriage (4) moving means.

The means (3) which execute the transferring of the nearly empty reel (1) from the first station (SN) to the second station (SI) comprise, in compliance with the example shown in the annexed drawings, two pushers (30) destined to act on said cones (C) inserted in the core (N) of the reel disposed in first station (SN), that is on the two ends of the reel projecting from said seats (AP), in order to push the reel towards the second station (SI) and, more in particular, towards the carriage (4) which is disposed in stand-by condition. In the example, each of said two pushers (30) is formed by a lever hinged with one of its ends to a fixed part of the structure (SF), the axis of hinge (31) being parallel to the axis of the reel (1); the lever is connected, at the opposite end, to an actuator (32) which, when activated, determines the rotation of said lever about the axis of hinge (31). Said pushers are disposed externally to the support seats (AP). In the annexed drawings only one pusher is visible, since it is shown only a side of the device. Each of said levers (30) has a central appendix (33) with a concave end (34) for a better engagement with the corresponding end of the reel (1). The arrow “A” represents the activation of the actuator (32), that is the extension of the respective rod, which corresponds to the rotation (counter-clockwise in the drawings) of the lever (30) as represented by the arrow “B”. The deactivation of actuator (32), that is the retraction of the relevant rod, involves the contrary rotation of the lever (30) and, therefore, the restoration of the normal stand-by or rest condition of this mechanism as shown in FIG. 3 and FIG. 4.

However, the particular mechanism utilized for transferring the reel (1) from the first station (SN) to the second station (SI) can be of any other type. Said carriage (4) is supported by a structure (5) developing between said second and the third station (SI, SP), that is upstream of the first station (SI) with respect to the direction (UC) of the paper exiting from the unwinder.

More particularly, said structure (5) is provided with two horizontal sides (50) developing mainly longitudinally, each of which having an external rectilinear track (51) acting, as further described below, as a guide element for the carriage (4). In the figures of the annexed designs, it is shown only one side (50) of the structure (5). In the example, said track (51) is horizontal.

Said carriage (4) comprises two forks (40), one for each of the two sides (50) of the structure (5). Each of said forks is provided, on its external side, with a lower “L”-shaped appendix (41) whose end slides in the track (51) of a corresponding side (50) of the structure (5). In this way, the carriage (4) is guided on the structure (5). In the figures of the annexed designs, it is visible only one of said forks (40).

Each of said forks (40) supports two idle rubber wheels (6) having identical external diameter. The two wheels (6) are mounted with the respective axes (r-r) parallel to the longitudinal axis (b-b) of the reel (1), that is oriented orthogonally regarding the two arms of the respective fork (40). In the example, the mounting of the two wheels (6) on the fork (40) is realized by means of two corresponding pins (60) whose axes (r-r) are disposed on a same horizontal plane and whose distance is such that, given the external diameter of the wheels (6), a corresponding end of the core (N) projecting from the reel (1) can be supported on the wheels (6) free to rotate about its axis (b-b). In other words, as shown in FIG. 3 and FIG. 5, there is an in-line disposition of the two wheels (6) supported by each of the forks (4) and the distance between the axis of the two wheels is such that a surface portion of the end of the core (N) projecting from the reel (1) can be supported on the upper internal sectors (6S) of the wheels. In practice, the carriage (4) is a cradle supporting the nearly empty reel (1), said reel (1) being free to rotate about its longitudinal axis.

Said carriage (4) is moved along the support structure (5) by means of a mechanism comprising, for each of the two sides of the carriage, an annular chain (7) gearing with a toothed spool fixed on the output (70) of a motor reducer (71) and engaging a plurality of guide toothed spools (72). A portion of the chain is fixed on the inner side of a correspondent fork (40). In practice, the movement of the chain (7) driven by the motor reducer (71) determines the movement of the carriage (4).

In the drawings, particularly in the schemes of FIG. 1, FIG. 2 and FIG. 9, the carriage (4) is represented in a plurality of operating positions, that is in the station (SI), in the station (SP) and in the station (SN).

The chain (7) is bi-directionally driven by the motor reducer (71), moving the carriage (4) alternatively between the stations (SI) and (SP), as indicated by the double arrow (G).

The carriage (4) is provided, on each of its sides, with a brake destined to act on the wheels (6), and, therefore, to slow down the rotation of the reel (1) about its axis (b-b), as further described below.

In the examples given in FIG. 6 and FIG. 7, said brake is made of a body (8) with a concave front surface connected to a linear actuator (80) which, in turn, is fixed on the inner face of one of the two forks of the correspondent side of the carriage (4), so that the body (8) is behind one of the wheels (6). In the example, the brake is disposed behind the posterior wheel (6) of the couple of wheels, with the actuator being horizontally oriented. The contact between said body (8) and the wheel (6), determined by the activation of actuator (80), involves the braking of the wheel and, therefore, of the reel (1) whose core (N) is supported by the wheels (6) of the carriage (4) as previously said.

In the example represented in FIG. 2, the carriage (4) has, in correspondence of each of its sides, a lateral appendix (42) having a concave side turned towards the top and towards the wheels (6). The function of said appendix (42) is described below.

A possible operating cycle of the device, reference being made to the scheme of FIG. 1, is the following.

A photoelectric cell (9) controls the diameter of the reel (2) placed with the ends of its core on the support seats (AP) of the station (SN); when the photo-cell senses that the diameter of the reel has been reduced to a predetermined value, the same photo-cell emits a signal which is transmitted to a programmable control unit (UE)—structurally and functionally known by the technicians of the industrial automation—which commands the activation of actuator (32) and, therefore, the rotation (B) of lever (30). Therefore, the reel is transferred from the station (SN) to the station (SI) where the carriage (4) is disposed to receive the nearly empty reel (1). A photoelectric cell (90), visible only in the scheme of FIG. 8, senses the presence of the reel (1) on the carriage (4) and supplies, by means of the unit (UE), an assent signal for the activation of motor reducer (71) which, correspondingly driving the chain (7), moves the carriage (4) with a predetermined speed along the structure (5) until the carriage is disposed in the station (SP). Meantime, the reel (1) is free of rotating about its axis (b-b) and, therefore, it continues to supply paper to the machines disposed downstream of the unwinder (S); moreover, the unit (UE) commands the lowering of the mechanical arm (MA), activating the respective actuators (A1, A2), arm on which a new reel is already ready for replacing the one removed from the station (SN). The arm (MA) is known to the technicians working in this field. When the carriage (4) arrives to the station (SP), another photoelectric cell (91), represented in the scheme of FIG. 8, by means of the unit (UE) supplies an assent signal for the activation of actuator (80) and, therefore, for the braking of the wheels (6). In such a way, the rotational speed of the nearly empty reel (1) is controlled. This determines a more precise and effective unwinding of the reel (1), without excessive slackening of the paper which could compromise the reel change operation.

The unwinder (S) comprises means, which can be of known type to the technicians of this field, intended to join the initial edge or head-edge of the paper supplied by the new reel (2) with the final edge or tail-edge of the paper supplied by the reel (1) disposed in the station (SP). The unwinder also comprises means, which can be of known type to the technicians of the field, intended to cut the tail-edge of the paper supplied by the reel (1) disposed in station (SP) once said union is executed. These operations are not described in detail since they can be done according to known techniques.

The exhausted reel (1) is then removed from the station (SP) with the aid of a bridge crane (not visible in the drawings) or any another equipment normally available in plants making use of unwinders. Finally, the carriage (4) is brought back in the station (SI) in order to be ready for another cycle.

With reference to the scheme of FIG. 2, the operating cycle of the present device differs only in that the carriage (4) is used also for delivering the exhausted reel (1) to a conveyor belt or similar means (NT) which removes the exhausted reels from the unwinder. More particularly, said conveyor (NT) is disposed upstream and lowered with respect to the structure (5) and it is oriented parallel to the axes of reels (1, 2). Moreover, the structure (5) is downwardly prolonged in its rear part, thus realizing a reentering portion which is inclined and downwardly oriented, so that the carriage (4) can pass over the conveyer (NT). When the carriage (4) with the reel (1) arrives in correspondence of the conveyer (NT), after having passed the station (SP), the reel (1) (whose core is supported by the appendixes 42 of the carriage) is intercepted by the conveyor belt which disengages it from the hooks constituted by said appendixes (42) while the carriage (4) moves downwardly. In FIG. 2 the carriage (4) is represented in the station (SN), in correspondence of the conveyor (NT) while it delivers the reel (1) to the conveyor, and in a lower and more remote position with respect to the conveyor, that is, unloaded. Therefore, a portion of the path followed by the carriage (4) is horizontal and a successive portion is diagonal or approximately vertical.

In the drawings, the reference (92) indicates a sensor destined to sense the presence of the reel, mounted on the carriage (4) between the two wheels (6).

With reference to the example shown in the FIGS. 9 to 11 of the annexed drawings, a device in compliance with the present invention can be used in an unwinder of the type in which a nearly empty reel is transferred from a station (SN), in which the reel rotates about its longitudinal axis until the attainment of a condition of incipient exhaustion (condition in which the diameter of the reel reaches a predetermined value which is smaller than the initial value), to a station (SP) in which it can continue to rotate about its longitudinal axis until complete exhaustion, that is until a new reel is positioned in the first station (SN) replacing the nearly empty one. With respect to the example shown in FIG. 1—, there is a direct transfer of the nearly empty reel from the station (SN) to the station (SP): practically, there isn't the intermediate passage in the afore-mentioned station (SI) and the previously described transferring mechanism (3) is not required. More particularly, in the station (SN) the reel which is normally being unwound is supported by the cones (C) inserted in the mandrel (CO) of the two axial ends of the core (N), as visible in FIG. 11A. When the diameter of the reel is reduced to a pre-established value, as sensed by the above-mentioned sensor (9), the cones (c) are disengaged from the mandrels (CO), as schematically shown in FIG. 11B. Consequently, the reel (1), which is no longer supported by the cones (C), for gravity leans on the wheels (6) of the carriage (4) waiting below in stand-by position. At this point, the carriage (4), once sensed the reel (1) by means of the sensor (92), is carried to the station (SP), as previously described. In the meantime, the mechanical arm (MA) puts a new reel (2) in the station (SN). Once unloaded, the carriage (4) is returned back to its initial position, that is under the reel (2) in phase of normal unwinding. Regarding to this aspect, it is observed that the working position of the carriage (4) is such that the wheels (6) can freely pass under the mandrels (C) of the reel (2), without any interference, so the carriage (4) can be freely brought back in correspondence of the station (SN) even if in the same station a new reel (2) has been positioned.

The cones (C), with the relevant extraction/retraction mechanisms, that is engagement/disengagement of the mandrels (CO) on the axial ends of the reels, are supported by the structure of the unwinder (S) in correspondence of two sides of the same. The functioning and the structure of said cones (C) are known to the technicians working in this field and, therefore, it will be not described in detail.

As in other figures of the annexed drawings, in FIG. 9 the carriage (4) is represented in station (SN) ad also in station (SP).

An operating method in compliance with the present invention comprises, within a reel change cycle in an unwinder, a step of transferring a nearly empty reel (1) from a station (SN) in which the reel (1) rotates about its longitudinal axis until the attainment of a condition of incipient exhaustion (condition in which its diameter reaches a pre-established value, smaller of the initial diameter) to a station (SP) in which it can continue to rotate about its longitudinal axis until the complete unwinding, that is until a new reel is placed in the first station (SN) and replaces the nearly empty reel, said transferring being operated at a predetermined translation speed along a predetermined path.

Moreover, an operating method in compliance with the present invention comprises a step of controlling the rotational speed of said nearly empty reel (1) at the end of said transferring path.

Practically, an operating method in compliance with the present invention, comprises moving the nearly empty reel (1) along a pre-established path, with a controlled speed, said path developing between more operating stations of an unwinder. An operating method in compliance with the present invention comprises also a step of controlling the rotational speed of the reel (1), particularly in correspondence of the end-point of said transferring path.

With reference to the previously described examples, the transferring of the nearly empty reel (1) along the path comprised between the station (SN) and the station (SP) can be continuous or direct, or discontinuous with an intermediate transferring.

Practically, the construction details may vary in any equivalent way as far as the shape, dimensions, elements disposition, nature of the used materials are concerned, without nevertheless departing from the scope of the adopted solution idea and, thereby, remaining within the limits of the protection granted to the present patent.

Claims

1. Device for moving paper reels in an unwinder of the type in which a nearly empty reel is moved along a predetermined path between more operating stations in each of which the reel is free to rotate about its longitudinal axis, the device being disposed and acting between the operating stations and comprising: a carriage intended to support a nearly empty reel and movable between said operating stations, the reel being free to rotate about its longitudinal axis on the carriage;a structure supporting said carriage;means for moving said carriage between said operating stations;means for controlling said means for moving the carriage, wherein said carriage is provided on each of its sides with a brake and two wheels, said brake acting on said wheels for slowing down the rotation of said reel about the longitudinal axis thereof.

2. Device according to claim 1, wherein said path is comprised between a first station in which the reel rotates about its longitudinal axis until the attainment of a condition of incipient exhaustion and a station in which the reel can continue to rotate about its longitudinal axis until the complete exhaustion, that is until a new reel is placed in said first station substituting the nearly empty one.

3. Device according to claim 1, wherein said path is comprised between an intermediate station in which the reel is transferred, coming from a station in which the reel rotates about its longitudinal axis until the attainment of a condition of incipient exhaustion, and a station in which the reel can continue to rotate about its longitudinal axis until its complete exhaustion.

4. Device according to claim 3, further comprising an automatic means for transferring said reel from said station, in which the reel rotates about its longitudinal axis until the attainment of a condition of incipient exhaustion, to said intermediate station, the latter being placed at the beginning of said path.

5. Device according to claim 4, wherein said means executing the transferring of the nearly empty reel from said station to said station comprises two pushers destined to act on two ends of the reel projecting from support seats which are intended to support two axial ends of the reel, in order to push the reel towards said intermediate station and, more, in particular, towards the carriage waiting therein.

6. Device according to claim 5, wherein each of said pushers is constituted of a lever which is hinged, at one of its ends, to a fixed part of the fixed structure of the unwinder, the hinge-axis being parallel to the axis of the reel, and connected, at the opposite end, to an actuator which, when activated, determines the rotation of the same lever about the respective hinge-axis.

7. Device according to claim 1, wherein said structure has two horizontal sides each of which being provided with an external rectilinear track defining a guide element for the carriage.

8. Device according to claim 7, wherein said track is horizontal.

9. Device according to claim 1, wherein said carriage comprises two lateral forks.

10. Device according to claim 9, wherein each of said forks is provided, on its external side, with a lower “L”-shaped appendix whose end slides in a track of a corresponding side of the structure.

11. Device according to claim 9, wherein each of said forks supports two wheels.

12. Device according to claim 11, wherein the axes of said two wheels are parallel to the longitudinal axis of the reel, i.e. oriented orthogonally with respect to the arms of the respective fork.

13. Device according to claim 11, wherein said two wheels are mounted on the fork by means of two correspondents pins whose axes are disposed on a same horizontal plane and whose distance is such that, given the external diameter of the wheels, a corresponding end of the core projecting from the reel can be supported on the wheels free to rotate about its own axis.

14. Device according to claim 1, wherein said carriage is moved by means of a mechanism comprising, for each of the two sides of the carriage, a chain connected to a motor-reducer and ring-closed on a plurality transmission spools.

15. Device according to claim 14, wherein said chain is activated bi-directionally by the motor-reducer, moving the carriage alternatively between said operating stations of the unwinder.

16. Device according to claim 1, wherein said braking means comprises a brake with a body with concave frontal surface connected to a linear actuator which, in turn, is fixed on the carriage, said body being behind one of the wheels.

17. Device according to claim 1, wherein said carriage is provided, in correspondence of each of its sides, with a lateral appendix having a concave part.

18. Operating method executable during a change reel cycle in an unwinder, the method comprising: a step of transferring a nearly empty reel from a station in which the reel rotates about its own longitudinal axis until the attainment of a condition of incipient exhaustion to a station in which it can continue to rotate about its longitudinal axis until the complete exhaustion, that is, until a new reel is disposed in the first station to replace the nearly empty reel, said transferring step being executed at a predetermined speed along a predefined path;a step of controlling of the rotational speed of said nearly empty reel, wherein said step of controlling the rotational speed of the nearly empty reel is executed at the end of said transferring step by lowering the rotational speed of the nearly empty reel.

19. Method according to claim 18, wherein said transferring is operated in two successive steps, with a step of transferring from said station in which the reel rotates about its own longitudinal axis until the attainment of a condition of incipient exhaustion to an intermediate station and a step of transferring from the intermediate station to said station in which it can continue to rotate about its longitudinal axis until the complete exhaustion.

20. Method according to claim 18, further comprising, subsequently to the transferring of said reel in said station in which it can continue to rotate about its longitudinal axis until the complete exhaustion, a step of positioning the exhausted reel on a conveyer which removes it from the unwinder.

21. Method according to claim 20, wherein during the positioning of the exhausted reel on the conveyer, the exhausted reel is guided.