GB2286181A

GB2286181A - Unwinding and splicing strip material.

Info

Publication number: GB2286181A
Application number: GB9426388A
Authority: GB
Inventors: Piero Barzano
Original assignee: IMS SpA
Current assignee: IMS SpA
Priority date: 1994-02-03
Filing date: 1994-12-30
Publication date: 1995-08-09
Anticipated expiration: 2014-12-30
Also published as: SE9500083L; GB2286181B; IT1269502B; DE19503398A1; SE507832C2; SE9500083D0; ITMI940191A1; GB9426388D0; ITMI940191A0

Abstract

A method comprises unwinding a roll 14', axially translating roll 14' to maintain the unwound strip 19 in a pre-established position (sensed at 26); axially translating a replacement roll 14 to maintain at least its first coil in a position substantially laterally aligned with the strip 19 during the splicing between a trailing edge of roll 14' and a leading edge of roll 14'. Rotating supports 13, 13' for the rolls are supported by a carriage 27 adjustable in a direction parallel to the axies of the rolls to maintain the pre-established lateral position of strip 19. A second carriage 29, carried on carriage 27, moves the second roll to align it with the strip and maintain such alignment despite adjustment movements of carriage 27. Splicing is effected at 31 using adhesive 37 on the replacement strip. <IMAGE>

Description

2286181 1 "Method and machine for unwinding and splicing rolls of material

in strip form" There are well known machines in the continuous printing and packaging technique which unwind a roll of material at high speed into a strip to be fed to the system. In order to avoid the system coming to a standstill whenever a depleted roll has to be changed, numerous unwinding machines have been proposed which automatically splice the trailing end of the strip from the roll nearing completion with the leading end of the strip of a new roll, so as to ensure continuous feeding.

For example, there are known unwinding machines provided with r rotary supporting assembly which comprises supports to maintain two rolls in a parallel position. The supporting assembly is powered by a motor to enable it to rotate around its axis of symmetry so as to alternately shift one of the two supports into a roll unwinding position and the other into a roll loading/unloading position. In this way, while one roll is being unwound on one support, a new roll can be fitted on the other support. As the roll being unwound gradually comes to an end, the supporting assembly rotates so as to cause the two rolls to exchange places. When the roll being unwound has run out completely, a splicing device joins the trailing end of it, as it moves along, to the 'Leading edge of the new roll, which is now in the unwinding position.

The depleted roll, which is now in the loading /iinloading 2 position, can consequently be replaced with a new roll for the next changover. In unwinding machines it is obviously important for the unwound strip to always maintain a precise crosswise position, imposed by the machines it is being fed into. However, due to the tolerances in winding the rolls, it is not sufficient to simply pay attention to the crosswise position when the roll is fitted on the machine. In fact, due to machining tolerances, very often the rolls are not wound precisely coil on coil and consequently as it unwinds the strip tends to sway crosswise. For this reason, unwinding machines are provided with sensors for detecting the position of the lateral edge of the strip (or of a coloured reference stripe substantially parallel to said edge) which control means for the axial translation of the roll being unwound so as to keep the edge of the strip in a pre-established position. For example, the aforementioned twin-roll machine has the entire rotary supporting assembly mounted on a motorized carriage to enable it to shift crosswise to the unwinding direction of the strip when commanded to do so by the edge position sensor. Even though this solution allows the strip to be held in the correct crosswise position as it unwinds, when the roll is changed a lateral offset of almost random width is created in the splicing area, due to the fortuitous positioning of the lateral edge of the end of the first strip compared to the posit-,:ton of the lateral edge of the 8 1# 3 start of the second strip. This offset depends upon winding imperfections in the first roll as well as upon winding imperfections in the second roll, which are wholly fortuitous. The relative lateral offset between the two strips can thus give rise to a step of various centimetres on the feed front of the splice which consequently jams up the system and causes laceration and/or distortion of the strip fed into it. In the known machines attempts have been made to solve the problem manually, by getting the operator in charge of fitting the rolls to visually check the alignment of the lateral edge of the new roll with respect to the roll being unwound. However, in addition to the inevitable -inaccuracy resulting from this way of operating (especially at the highest operating speeds), it should also be considered that the position of the lateral edge of the innermost coils (which will be the ones involved in the splicing) cannot be seen directly and consequently the alignment carried out will continue to be affected by the fortuitous deviations between the coils. The general scope of this invention is to obviate the aforementioned drawbacks by proving a method and a machine for unwinding and splicing products in strip form, which automatically prevents excessive lateral offsets between the edges of the spliced strip. This scope is achieved, according to the invention, by providing a method for unwinding and sequentially splicing rolls of material in strip form, comprising the automatic 4 steps of: - unwinding a first roll into a strip; - axially translating the first roll to maintain the lateral edge of the strip Ibeing unwound in a pre-established position; - axially translating a second roll parallel to the first roll to maintain the lateral edge at least of the first coil of the second roll in a position substantially aligned with the lateral edge of the strip being unwound at least close to a pre-established area; - splicing a trailing edge of the first roll with a leading edge of the second roll in said pre- established area. According to this method a machine is provided for unwinding and splicing rolls of material in strip form comprising a pair of motorized rotating supports on which a first roll and a second roll to be sequentially unwound are disposed with parallel axes, the pair of supports being mounted on a first motorized supporting carriage which is movable in a direction parallel to the axis of the rolls, unwinding means unwinding the f irst roll into a strip, a first position sensor detecting the lateral position of the strip being unwound and transmitting a control signal to move the first carriage in order to maintain the strip being unwound in a pre-established lateral position, splicing means splicing a trailing edge Of the strip from the first roll with a leading edge of the second roll, characterized by the fact tha-IC- the p support of the second roll is mounted on the first carriage by means of its own individual motorized second carriage for axial movement of the corresponding roll, before actuation of the splicing means control means controlling the movement of the second carriage to maintain the lateral edge at least of the first coil of the second roll in a position substantially aligned with the lateral edge of the strip being unwound at least close to the splicing means.

The innovatory principles of this invention and its advantages with respect to the known technique will be more clearly evident from the following description of a possible exemplificative embodiment applying such principles, with reference to the accompanying drawings, in which: figure 1 shows a schematic side view of an unwinding machine according to the invention; - figure 2 shows a schematic rear view of the machine of figure 1.

The figures show an innovative unwinding machine, generically indicated by reference 10, which comprises a supporting assembly 11 which is motorized by a power unit 17 to rotate on command around an axis 18. In specular positions with respect to the axis of rotation 18, the supporting assembly 11 comprises motorized supports 13, 13' each axially supporting a respective roll 14, 14', with its axis parallel to the axis of rotation 18. The figures exemplificatively show the shapes 14, 14' 6 respectively of a roll still to be unwound and a roll almost completely unwound. The rotation of the supporting assembly 11 moves the rolls along the path 12 to shift then, from an upper waiting and initial unwinding position (occupied in figure 1 by the support 13) to a lower position (occupied in figure 1 by the support 131) for completion of the unwinding and loading of a new roll. Generically indicated by reference 19 in figure 1 is a path for the strip of material being unwound from a roll towards the delivery end of the machine. This path is defined by a plurality of idle or motor-driven guide rollers 20-22 and by tightening means, such as for example a pendulum tightener 23.

is The entire supporting assembly is mounted on a slide or carriage 27 movabIle parallel to the axis of the rolls by means of an actuator 28, which comprises sensors which detect the extent of its movement. Disposed along the path of the strip is a sensor 26 which detects a lateral edge of the strip, or a line printed on the strip parallel to said edge, and transmits a signal to the actuator 28 to slightly shift the roll being unwound so as to maintain the lateral edge of the strip in the preestablished position.

As can also be clearly seen in figure 1, the supporting assembly 11 comprises radial arms 15 disposed at- right angles with respect to the join between the supports 13, 13' to support idle guide rollers 16, 16' which, when the F 7 roll being unwound is shifted to the lower Position, maintain the strip being unwound in a position substantially tangent to the new upper roll and close to an operating position of a splicing and cutting unit 31. The splicing unit 31 is movable from a non-operative position, shown by the broken line in figure 1, to an operative position, shown by the continuous line in figure 1, in order to carry out the splice between the strips of the two rolls.

The leading edge of the new roll has an adhesive band 37, with the adhesive portion facing towards the outside of the roll. The machine 10 comprises a measuring arm 24, which is movable to bring a sensor 25 into contact with the periphery of the new roll 14, which cooperates with a synchronizing sensor 40 to accurately control the cutting and splicing operation. To carry out the splicing with the strip being unwound from the lower roll, the upper roll reaches a speed of rotation synchronous with the movement of the strip 19 and when the band 37 passes under the splicing unit 31, the latter cuts the strip and presses the trailing edge against the adhesive band 37, so as to _Join it overlapping the leading edge of the new strip. In this way the new roll begins to unwind while the depleted roll can be removed and replaced with a new roll. Subsequently, as the new roll gradually unwinds the supporting assembly rotates to shift it towards the lower position ready for the next 8 splicing operation. The machine can also comprise a unit (not shown) for covering the splice with a further adhesive band disposed on the opposite side of the splice with respect to the band 37. The description given so far is substantially of known technique. According to the innovative principles claimed herein, each of the supports 13, 13' is mounted on its own independent carriage 29, 29', moved by an actuator 30, 301 to axially translate the respective roll 14, 14' with respect to the carriage 27 of the supporting assembly. Each actuating device 30, 30' comprises a position sensor to detect the exact extent of the movements of the independent: carriages 29, 29'. The machine also comprises a sensing unit 32 disposed at the end of an arm 33 which is movable between a raised or non-operative position and a lowered or operative position (shown respectively by the continuous line and the broken line in figure 1) by means of an actuator 34. As can be clearly seen in figure 2, the sensing unit 32 comprises a sensor 36 to detect the lateral edge of the roll or a line printed close to the latter, similarly to the sensor 26 which reads on the unwound strip. Advantageously, in order to ensure the correct distance between the sensor 36 and the surface of the roll, disposed at the end of the arm 33 is an idle wheel 35 which, when the arm 33 shifts into its operative position, 1:

9 rests on the outer surface of the roll with a rolling plane disposed along a generatrix of the roll. Also advantageously, the sensor 26 and the arm of the sensor 36 are supported on the same carriage 39 so as to have aligned detection areas. The carriage can be moved crosswise to the strip to sirrii.ltaneoi-isl,.,7 establish the desired edge position for the strip being unwound and for the new roll ready to be spliced. To operate, the machine 10 comprises a processing unit 38, for example controlled by a microprocessor, of known technique and therefore not further described or shown, which receives the signals from the carriage position sensors 27, 29, 30 and from the sensors 25, 26 and 36, and emits control signals for translation of the carriages and is tor actuating the rotation of ';,.,he rolls and the supporting assembly, as well as for actuating the movement of the arms 24 and 33 and the splicing unit 31, thus constituting means for programmed control of the machine. When in operation, the carriages 27, 29 and 29' are initially disposed in their central position, and positioned on one of the supports is a roll of material in a strip to be unwound. The supporting assembly 11 is then rotated so as to position the roll in the upper position as shown in 14, the strip unwinding along the path 19 towards the system to be fed (of known technique and therefore not shown). In this situation the unit 31 is positioned in its non-operative position. While the roll unwinds, the sensor 26 checks the lateral position of the strip and correspondingly controls the carriage 27, so as to maintain the strip in the pre-established position regardless of the winding tolerances of the roll. While the roll unwinds, a new roll, prepared with the band of adhesive tape 37, is pos-itioned in the meantime on the opposing support (in a lower and therefore easily accessible position). As the roll being unwound gradually decreases in diameter the supporting assembly 11 rotates in an anticlockwise direction to reach the position shown in figure 1, in which the roll being unwound is in the lower end-of-unwinding position 1V, while the new roll is in the upper splicing position 13. After the roll being unwound has shifted from the upper position to the lower position, the splicing and cutting unit 31 can be placed in its operative position close to the surface of the new roll. At this point the arm 33 lowers to bring the wheel 35 in contact with the new roll (indicated by 14 in figure 1).

The carriage 29 is then moved by the controller 38 to bring the edge of the roll 14 in the position detected by the sensor 36 as being the position aligned with the correct position of the edge of the strip which is detected by the sensor 26. After having shifted the carriage 29 to the correct position, the arm 33 can be raised. After the carriage 29 has reached the correct position, for each lateral movement of' the carriage 27 to maintain 11 the strip being unwound in its correct position, the device 38 transmits a signal to the carriage 29 to move laterally by an identical distance but in the opposite direction to that of the carriage 27, so that the roll 14 remains substantially stationary with respect to the pre- established position. in this way, the initial coil of the roll 14 remains perfectly aligned with the strip being unwound from the roll 141 at least close to the splicing means 31.

When the roll 14 is nearing the end, the new roll 14 is made to rotate so that its peripheral speed is identical to the running speed of the strip being unwound. Moreover, the arm 17 is lowered so that the sensor 25 (for example a wheel with encoder) enters into contact with the periphery of the roll 14 to measure its development. Once it knows the development of the roll 14 and has detected with the sensor 40 one passage of the strip 37 in the cutting and splicing point of means 31, the device 38 is able to calculate in advance the precise instants of the next passages of the splicing point of the strip 37. In this way, the device 38 can transmit a signal to the cutting means (which have a known mechanical operating inertia) sufficiently in advance to carry out the cut and splice precisely on passage of the band 37 in the splicing point. The trailing end of the strip is thus spliced precisely on the adhesive band 37 and the new roll begins to unwind. After having carried out the splice, the depleted roll can 12 be removed and its place can be taken by a new roll ready for the next splice. The carriage supporting it can then be shifted to the position half way along its stroke and the machine is thus ready for a new phase of lateral alignment and splicing as described above. At this Point it will be clear that the intended scopes have been achieved, by providing a machine whereby it is possible to obtain perfect lateral alignment of the edges of the strip before and after the Join thanks to the preliminary alignment of the outermost edge of the new roll with the lateral edge of the strip being unwound. Lateral alignments have been obtained with the splicing method and the machine described above with deviations in the region of a millimetre which are conJ'equently wholly negligible compared to the deviations of several centimetres that are obtained with the known methods and machines. It should be pointed out that with the innovative use of A main carriage 27 for movement of the entire supporting assembly and individual carriages 29, 29' for movement of the individual rolls, the impossibility of compensating for the lateral error of the new roll with respect to the strip being unwound can never ever occur. In fact, at each change of roll, the corresponding individual carriage can be returned to its central position, while the position of the entire supporting assembly continues to vary following the progress of the strip being unwound. Consequently, there is no accumulation of lateral 13 deviations between one roll and the next. The foregoing description of an embodiment applying the innovative principles of this invention is obviously given by way of example in order to illustrate such innovative principles and should not therefore be understood as a limitation to the sphere of the invention claimed herein. For example, the path of the strip of material being iirrvjound may differ from the --)ne shown, _Just as the number of idle and motorized rollers disposed. along it may also 10 differ.

14

Claims

1. Unwinding and splicing machine for unwinding and splicing rolls of material in strip form comprising a pair of motorized rotating supporits (13, 13') on which a first roll (14 or 14') and a second roll (14' or 14) to be sequentially unwound are disposed with parallel axes, the pair oil supports (13', 13) being mounted on a first motorized supporting carriage (27) which is movable in a direction parallel to the axis of the rolls (14, 141), unwinding means (20-23) unwinding the first roll (14 or 14') into a strip (19), a first position sensor (26) detecting the lateral position of the strip being unwound and transmitting a control signal t6 move the first carriage (27) in order to maintain the strip being unwound in a pre-established lateral position, splicing means (31) splicing a trailing edge of the strip from the first roll (14 or 14') with a leading edge of the second roll (14' or 14), characterized by the fact that the support (13' or 13) of the second roll is mounted on the first carriage (27) by means of its own individual motorized second carriage (29' or 29) for axial movement of the corresponding roll, before actuation of the splicing means (31) control means (38) controlling the movement of the second carriage (29 or 291) to maintain the lateral edge at least of the f irst coil of the second roll in a. position substantially aligned with the lateral edge of the strip being unwound at least close to -1he splic--ng i z means.

2. Machine as claimed in claim 1, characterized by the fact of comprising a second position sensor (32) detecting the position at least of the first coil of the second roll, control means (38) transmitting said signal to means for moving the second carriage (419' or 29) until it reaches the position of substantial alignment and subsequent-ly transmitting a signal to the means for moving the second carriage to move the same distance in the opposite direction with respect to the movement of the first carriage (27).

3. Machine as claimed in claim 2, characterized by the fact that the second position sensor (36) is mounted on a movable arm (33) to shift tH-e sensor between a non-operative position at a distance from the second roll and an operative position close to the peripheral surface of the second roll.

4. Machine as claimed in claim 3, characterized by the fact that the movable arm (33) has a free end close to the second sensor (36) comprising means (35) which slidingly rest on the peripheral surface of the second roll.

5. Machine as claimed in claim 2, characterized by the fact that the first sensor (26) and second sensor (36) are mounted on an adjusting carriage (39) to adjust their movement parallel to the axis of the rolls.

6. Machine as claimed in claim 1, characterized by CL-&e fact that the pair of supports (13, 131) are mounted on the first carriage by means of a supporting assembly (11) 16 which on command moves the motorized supports (13, 131 along a circular path to shift them sequentially to and from a position for loading a roll on a respective support (13, 13'), an end of unwinding position, and a splicing and start of unwinding position, when a roll (14 or 141 is in the splicing position the other (14' or 14) being in the end of unwinding position, the supports (13, 131), each with its own individual second carriage (29, 291), becoming alternately a support for the first or for the second roll.

7. Machine as claimed in claim 1, characterized by the fact that the splicing means (31) are movable between a non-operative position spaced apart from the second roll (14' or 14) and ai operative position close to the second roll (14' or 14) with interposition of the strip (19) being unwound.

8. Machine as claimed in claim 1, characterized by the fact that disposed close to the periphery of the second roll (14' or 14) is a third sensor (40) which detects the passage of a band of adhesive tape (37) placed on the leading edge of the second roll for connection to the trailing edge of the strip, the sensor (40) transmitting a synchronizing signal to operate the splicing means (31).

9. Machine as claimed in claim 8, characterized by the fact that disposed in contact with the periphery of the second roll (141 or 14) is a fourth sensor (25) which measures the external development of the second roll for precise control of the splicing means (31) in relati. on to -c 17 said external development and the synchronizing signal of the third sensor (40).

10. Method for unwinding and sequentially splicing rolls of material in strip form, comprising the automatic steps of: - unwinding a first roll (14 or 14') into a strip; - axially translating the first roll to maintain the lateral edge of the strip being unwound in a preestablished position; - axially translating a second roll (14', 14) parallel to the first roll to maintain the lateral edge at least of the first coil of the second roll in a position substantially aligned with the lateral edge of the strip being un7ound at least close to a pre-established area; - splicing a trailing edge of the first roll. (14 or 141 with a leading edge of the second roll (14' or 14) in said preestablished area.

11. Method as claimed in claim 10, characterized by the fact of supporting the first and second roll on a first carriage for their simultaneous axial translation, placing between the first carriage and second roll a second individual carriage for axial translation of the second roll with respect to the first carriage; - controlling the movement of the first carriage to maintain the lateral edge of the strip being unwound in said first pre- established position; - controlling the second carriage to translate the second roll (14, 141) to the position of substantial alignment; 18 - detecting the reaching of said position of substantial alignment and, subsequently, at each translation of the first carriage controlling the translation of the second carriage by the same distance in the opposite direction to the translation of the first carriage to maintain the position of substantial alignment of the second roll during the splicing step.

12. Apparatus adapted to carry out the method of claim 10, comprising: means for unwinding a first roll (14 or 141) into a strip; means for axially translating the first roll to maintain the lateral edge of the strip being unwound in a pre-established position; means for axially translating a second roll (141, 14) parallel to the first roll to maintain the lateral edge at least of the f irst coil of the second roll in a position substantially aligned with the lateral edge of the strip being unwound at least close to a pre-established area; and means for splicing a trailing edge of the f irst roll (14 or 141) with a leading edge of the second roll (141 or 14) in said pre-established area.

13. Apparatus for unwinding and sequentially splicing rolls of material in strip form substantially as described herein with reference to and as illustrated in the accompanying drawings.

14. A method for unwinding and sequentially splicing rolls of material in strip form substantially as described herein with reference to and as illustrated in the accompanying drawings.

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