An unwinding unit and a method for unwinding materials from reels

Abstract

An unwinding unit, comprising: - a mandrel (12) configured for holding a plurality of side-by-side reels (R), - an indexing actuator (14) configured for stepwise moving the mandrel (12) to position in succession each reel (R) in an unwinding position, - a splicing device (16) configured for splicing a tail portion of a material (T) from a reel (R) previously in the unwinding position to a head portion of a material (T) from a reel (R) subsequently in the unwinding position.

Description

[0001] "An unwinding unit and a method for unwinding materials from reels"

[0002] ★ ★ ★ ★

[0003] Field of the Invention

[0004] The present invention relates to an unwinding unit for unwinding materials from rol ls or reels into a web process .

[0005] The invention has been developed in particular for the application in machines that use large quantities of continuous materials , such as tapes or webs , for instance machines for producing absorbent sanitary articles , packaging machines , machines for producing batteries , etc .

[0006] According to another aspect , the invention relates to a method for unwinding materials from rolls or reels .

[0007] In the following description reference to a reel also refers to roll materials .

[0008] Prior Art

[0009] Unwinding units are essential components in the handling of roll stored materials , particularly when changing from a used reel to a new one . The operation of these units involves several critical steps to ensure a smooth transition and maintain the continuity of the material being unwound .

[0010] Typically, unwinding units have two mandrel which support two reels , one of which is unwinding, and the other is in stand-by .

[0011] When the primary reel unwinding is expiring, the tail portion of the material from the expiring reel is spliced to the head portion of a material from a new reel .

[0012] High speed unwinding units may be equipped with an automatic changeover system, which allows the expired reel to be replaced by a new one swi ftly and without interrupting the machine ' s operation . This is particularly beneficial in high-speed production environments where downtime can be costly . The changeover process is usually facilitated by a control system that can detect the end of the material on an expiring reel and initiate the switch to a new reel , often involving a splice to j oin the end of the old material to the start of the new one .

[0013] Replacing an expired reel with a new reel requires a series of operations , including picking up a new reel located at a storage station, loading the reel onto an unwinder assembly and preparing the splice . These operations tend to occur at increasingly shorter intervals as the operating speed of the machines increases , so that these operations need to be performed as quickly and ef ficiently as possible .

[0014] Manual intervention by an operator is often required to change the reels and prepare the splice . The operator ' s role includes replacing the expired reel with a new one and preparing the splice .

[0015] Manual intervention during reel changeover has several drawbacks , among which :

[0016] - splice failures due to operator error, signi ficant downtime during a roll change i f material supply is exhausted,

[0017] - systems that require small roll supply for low modulus or high loft material are not easily threaded or introduce too many failures to splice or feed into a running active process ,

[0018] - operator fatigue .

[0019] Modern machines operate at increasingly higher speeds , so that the material unwinding speed tends to become faster and faster, increasing the frequency of reel changeover and increasing the risk of errors and machine arrests . Therefore , there is the need for unwinding units capable to carry out automatic reel changeover and minimi zing manual intervention .

[0020] Obj ect and summary of the invention

[0021] The obj ect of the present invention is to provide an unwinding unit and a method for unwinding materials from reels that solve the problem of the prior art .

[0022] In particular, an obj ect of the present invention is to provide an unwinding unit and a method for unwinding materials that would allow multiple reel changeover with automatic thread-up, automatic splice preparation, and automatic splicing .

[0023] According to the present invention, these obj ects are achieved by an unwinding unit and a method for unwinding materials having the features forming the subj ect of claims 1 and 8 .

[0024] Preferred features of the invention are defined in the dependent claims .

[0025] The claims form an integral part of the technical disclosure provided here in relation to the invention .

[0026] Brief description of the drawings

[0027] The present invention will now be described in detail with reference to the attached drawings , given purely by way of non-limiting example , in which :

[0028] - Figure 1 is a schematic side view of an unwinding unit according to the present invention,

[0029] - Figure 2 is a schematic perspective view of the unwinding unit of Figure 1 ,

[0030] - Figure 3 is a partial side view showing the part indicated by the arrow I I I in Figure 1 ,

[0031] - Figure 4 is a schematic view showing the step of gripping the tail portion of an expired reel , Figure 5 is a schematic view showing the application of an adhesive splicing material on the tail portion of an expired reel , and

[0032] - Figure 6 is a schematic view showing the splicing of the tail portion of an expired reel with the head portion of a new reel .

[0033] It should be appreciated that the attached drawings are schematic and that various figures may not be represented in the same scale . Also , in various figures some elements may not be shown to better show other elements .

[0034] Detailed description

[0035] With reference to Figures 1 and 2 , numeral reference 10 indicates an unwinding unit according to the present invention .

[0036] The unwinding unit 10 comprises a mandrel 12 having a mandrel axis X . The mandrel 12 is configured for holding a plurality of side-by-side reels R coaxial with each other . Each reel R has a respective material T wound cylindrically, that is with the turns overlapped to each other such that the width of each reel R is substantially equal to the width of the material T .

[0037] The mandrel 12 may be supported by a stationary structure 30 ( Figure 2 ) or by a movable carrier 32 ( Figure 1 ) . I f the mandrel 12 is supported by a movable carrier 32 , the reels R may be mounted on the spindle 12 when the movable carrier 32 is in a loading station or storage area . When the reels R mounted on a movable carrier 32 positioned in the unwinding unit 10 are all expired the movable carrier 32 is replaced by a new one carrying a set of new reels R previously mounted on the mandrel 12 .

[0038] The unwinding unit 10 comprises an indexing actuator 14 configured for stepwise moving the mandrel 12 with the plurality of side-by-side reels R mounted thereon . The indexing actuator 14 may be configured to move the mandrel 12 or the movable carrier 32 along the mandrel axis A to locate in succession each reel R of the plurality of side-by-side reels R in an unwinding position . The material T of the reel R in the unwinding position is aligned to a feeding direction A transverse to the mandrel axis X .

[0039] When the reel currently in the unwinding position expires , the indexing actuator 14 moves the mandrel 12 along the mandrel axis X by a step substantially equal to the width of the reels R, so that a new reel is brought in the unwinding position . As mentioned, the indexing actuator 14 may move directly the mandrel 12 or the movable carrier 32 carrying the mandrel 12 .

[0040] The unwinding unit 10 comprises a splicing device 16 configured for splicing a tail portion of a material T from an expiring reel R with a head portion of a material T from a new reel R .

[0041] The expired reel R is a reel R which was previously in the unwinding position . The new reel R is a reel which was adj acent to the expired reel , and which is brought in the unwinding position by the stepwise axial movement of the mandrel 12 after the reel R previously in the unwinding position has expired .

[0042] Preferably, only the reel R in the unwinding position is freely rotatable around the mandrel axis X, whereas the reels R other than the reel R in the unwinding position are non-rotatable around the mandrel axis X .

[0043] In a possible embodiment , all the reels R are rotatably mounted on the mandrel 12 and a braking device 20 is provided for holding in a non-rotatable configuration all the reels R other than the reel R in the unwinding position . The braking device 20 may include a bar 34 pressed against the outer surfaces of the reels R other than the reel R in the unwinding position . In possible embodiments , the braking device 20 may include expansion elements provided on the mandrel 12 and selectively actuated to lock the reels R other than the reel R in the unwinding position .

[0044] The unwinding unit 10 comprises a pick-up device 18 configured for picking-up the head portion of the material T from a new reel R in the unwinding position and for threading the head portion of the material T into the splicing device 16 .

[0045] The pick-up device 18 may comprise a suction belt 22 configured for contacting an outer surface of the reel R in the unwinding position .

[0046] As shown in Figure 3 , the pick-up device 18 may be movable between an inoperative position in which the suction belt 22 is spaced apart from the outer surface of the reel R in the unwinding position and an operative position in which the suction belt 22 is in contact with the outer surface of the reel R in the unwinding position .

[0047] The head portions of the materials T are free on the outer surfaces of the respective reels R, so that the materials T are ready to be threaded into the splicing device 16 once the respective head portions are picked-up by the suction belt 22 . In this way there is no need for a manual intervention to detach the head portions of the materials T from the outer surfaces of the respective reels R . The end edges of the materials T may be aligned with each other and the reels may be mounted on the mandrel 12 with a predetermined orientation such that the suction belt 22 picks-up the head portions of the materials T always in the same position . With reference to Figure 4 , the splicing device 16 may comprise a gripping device 36 configured for selectively holding in a stationary position the tail portion of a material T from an expiring reel R . The gripping device 36 is activated when a sensor 38 detects that the reel R in the unwinding position is expiring . The gripping device 36 may include a roller 40 which presses the tail portion of the material T against a stationary anvil 42 . The gripping device 36 holds the tail portion of the material T in a stable position and prevents loss of the normal path .

[0048] With reference to Figure 5 , the splicing device 16 may comprise an adhesive material applicator 24 configured for applying an adhesive splice material on the tail portion of the material T from the expiring reel R . The adhesive material applicator 24 may be movable between an inoperative pos ition and an operative position, for instance in a direction parallel to the mandrel axis x . The adhesive material applicator 24 may comprise an adhesive material supply roll 44 and a takeup roll 46 which collects a protective film detached from the adhesive splice material unwound from the adhesive material supply roll 44 .

[0049] Once the tail portion of the material T is held stationary in a stable position, the adhesive material applicator 24 applies a section of adhesive splice material on the tail portion of the material T .

[0050] With reference to Figure 5 , the splicing device 16 may comprise a cutting device 26 configured for cutting the tail portion of the material T downstream of the adhesive material applicator 24 .

[0051] With reference to Figures 4 and 6 , the splicing device 16 may comprise two splicing rolls 50 , 52 which impart an S-shaped path to the tail portion of the material T . The suction belt 22 of the pick-up device 18 threads the head portion of the material T from a new reel R in the unwinding position between the two splicing rolls 50 , 52 . In this way, the head portion of the material T from the new reel overlaps the tail portion of the material T from the expiring reel R, on which a section of adhesive splice material has been applied by the adhesive material applicator 24 . The two splicing rolls 50 , 52 press together the overlapped head and tail portions so that they are spliced by the adhesive splice material .

[0052] Splicing methods alternative to the application of adhesive splice material may include application of glue ( e . g . hot melt glue ) on the tail portion of the material T , or welding ( e . g . ultrasonic welding) between the overlapped head and tail portions .

[0053] Splicing between the head and tail portions is carried out while the tail portion of the material T is stationary . As shown in figure 1 , the unwinding unit 10 may comprise a buf fer 28 located downstream of the splicing device 16 which continues to supply material T to a processing machine while the tail portion of the material T is held stationary .

[0054] The cutting device 26 cuts the tail portion of the material T after the overlapped head and tail portions have been spliced . After cutting the tail portion of the material T the spliced materials T are free to move in the feeding direction A. The splicing rollers 50 , 52 and the adhesive material applicator 24 are disengaged from the material T and the material T from the new reel R is supplied to the processing machine . The above steps are repeated when the reel currently unwinding is expiring .

[0055] The unwinding unit 10 in operation carries out an unwinding method comprising : holding a plurality of side-by-side reels R coaxial with each other on a mandrel 12 having a mandrel axis A, each reel R having a respective material T wound cylindrically,

[0056] - positioning a reel R of the plurality of side-by- side reels R in an unwinding position,

[0057] - unwinding a material from the reel R in the unwinding position and feeding the material T in a feeding direction A transverse to the mandrel axis (X ) , detecting when the reel R in the unwinding position is expiring,

[0058] - stepwise moving the mandrel 12 along the mandrel axis X to bring a new reel R of the plurality of side- by-side reels R in the unwinding position,

[0059] - picking-up a head portion of the material T of the new reel R and threading the head portion into a splicing device 16 , and splicing a tail portion of the material T from the expiring reel R previously in the unwinding pos ition to the head portion of the material T from a new reel R subsequently in the unwinding position .

[0060] The method may provide that the reel R in the unwinding position is rotatable around the mandrel axis X while the reels R other than the reel R in the unwinding position are non-rotatable around the mandrel axis X .

[0061] All the reels R may be rotatably mounted on the mandrel 12 and a braking device 20 may be provided for holding in a non-rotatable configuration all the reels R other than the reel R in the unwinding position .

[0062] The method may comprise picking-up the head portion of the material T on the new reel in the unwinding position by a suction belt 22 contacting an outer surface of the new reel R .

[0063] The method may comprise moving the suction belt 22 between an inoperative position in which the suction belt 22 is spaced apart from the outer surface of the new reel R and an operative position in which the suction belt 22 is in contact with the outer surface of the new reel R .

[0064] The method may comprise applying an adhesive material on the tail portion and cutting the tail portion after having applied thereon said adhesive material and after having spliced the head and tail portions .

[0065] The method may comprise selectively holding in a stationary position the tail portion during application of the adhesive splicing material , splicing the head and tail portions , and cutting the tail portion .

[0066] Of course , without prej udice to the principle o f the invention, the details of construction and the embodiments can be widely varied with respect to those described and illustrated here , without departing from the scope of the invention as defined by the claims that follow .

Claims

CLAIMS1. An unwinding unit, comprising:- a mandrel (12) having a mandrel axis (X) and configured for holding a plurality of side-by-side reels (R) coaxial with each other, each reel (R) having a respective material (T) wound cylindrically,- an indexing actuator (14) configured for stepwise moving said mandrel (12) along said mandrel axis (A) to position in succession each reel (R) of said plurality of side-by-side reels (R) in an unwinding position, wherein the material (T) from the reel (R) in the unwinding position is aligned to a feeding direction (A) transverse to said mandrel axis (X) , a splicing device (16) configured for splicing a tail portion of a material (T) from a reel (R) previously in said unwinding position to a head portion of a material (T) from a reel (R) subsequently in said unwinding position, and- a pick-up device (18) configured for picking-up the head portion of a material (T) from a reel (R) subsequently in said unwinding position and for threading said head portion into said splicing device (16) .

2. The unwinding unit of claim 1, wherein the reel (R) in said unwinding position is rotatable around said mandrel axis (X) and wherein the reels (R) other than the reel (R) in said unwinding position are non-rotatable around said mandrel axis (X) .

3. The unwinding unit of claim 2, wherein all said reels (R) are rotatably mounted on said mandrel (12) and wherein a braking device (20) is provided for holding ina non-rotatable configuration all the reels (R) other than the reel (R) in said unwinding position.

4. The unwinding unit of claim 1, wherein said pickup device (18) comprises a suction belt (22) configured for contacting an outer surface of the reel (R) in said unwinding position.

5. The unwinding unit of claim 4, wherein said pickup device (18) is movable between an inoperative position in which the suction belt (22) is spaced apart from the outer surface of the reel (R) in said unwinding position and an operative position in which the suction belt (22) is in contact with the outer surface of the reel (R) in said unwinding position.

6. The unwinding unit of claim 1, wherein said splicing device (16) comprises an adhesive material applicator (24) configured for applying an adhesive splice material on said tail portion and a cutting device (26) configured for cutting said tail portion downstream of said adhesive material applicator (24) .

7. The unwinding unit of claim 6, wherein said splicing device comprises a gripping device (36) configured for selectively holding in a stationary position said tail portion during application of the adhesive material.

8. The unwinding unit of claim 1, comprising a buffer (28) located downstream of said splicing device(16) .

9. A unwinding method, comprising:- holding a plurality of side-by-side reels (R) coaxial with each other on a mandrel (12) having a mandrel axis (A) , each reel (R) having a respective material (T) wound cylindrically, stepwise moving said mandrel (12) along said mandrel axis (X) to position in succession each reel (R) of said plurality of side-by-side reels (R) in an unwinding position, wherein the material (T) of the reel (R) in said unwinding position is aligned to a feeding direction (A) transverse to said mandrel axis (X) ,- picking-up a head portion of the material (T) wound on the reel (R) subsequently in said unwinding position and threading said head portion into a splicing device (16) , and splicing a tail portion of a material (T) from a reel (R) previously in said unwinding position to a head portion of a material (T) from a reel (R) subsequently in said unwinding position.

10. The unwinding method of claim 9, wherein the reel (R) in said unwinding position is rotatable around said mandrel axis (X) and wherein the reels (R) other than the reel (R) in said unwinding position are non- rotatable around said mandrel axis (X) .

11. The unwinding method of claim 10, wherein all said reels (R) are rotatably mounted on said mandrel (12) and wherein a braking device (20) is provided for holding in a non-rotatable configuration all the reels (R) other than the reel (R) in said unwinding position.

12. The unwinding method of claim 9, comprising picking-up the head portion of the material (T) wound on a reel subsequently in said unwinding position by asuction belt ( 22 ) contacting an outer surface of the reel (R) in said unwinding position .

13. The unwinding method of claim 12 , comprising moving said suction belt ( 22 ) between an inoperative position in which the suction belt ( 22 ) is spaced apart from the outer surface of the reel (R) in said unwinding position and an operative position in which the suction belt ( 22 ) is in contact with the outer surface of the reel (R) in said unwinding position .14 . The unwinding method of claim 9 , comprising applying an adhesive splicing material on said tail portion and cutting said tail portion after having applied thereon said adhesive splicing material .15 . The unwinding method of claim 14 , comprising selectively holding in a stationary position said tail portion during application of the adhesive splicing material .

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