FR2620117A1 - DIVIDING AND REENROUTING STRIP MACHINES - Google Patents

Abstract

A machine according to the invention comprises a front part 12 and a rear part 14 which are of identical structures and operate in the same way, and cutting members 18 arranged between said front and rear parts. Each part 12, 14 comprises pressure rolls 26 and supports 30 for rewinding roll cores R. In operation, the contact pressure between rolls 26 and rolls R is kept constant. The rewinding rolls R move as they grow during formation, in the direction of the web to be wound on the core. The machine can produce good quality, large width and large diameter R rolls at high speed from smooth sheet material.

Description

I1 2620117

  Dividing machines and rewinding machines.

  The present invention relates to web dividing and rewinding machines and, more particularly, rewinding machines which are provided for dividing a relatively broad web-like thin material, such as plastic or paper, into a plurality of longitudinal webs or subbands. of prescribed widths, rewind each sub-band into a separate rewind roller, and pull the rewind rollers out of the machine. The machine of the present invention can not only be associated with an unwinding unit of a feeding or rolling roll, as a cutting and re-laminating machine, but also a machine for processing the web material provided with the processing device. desired band, such as a rolling device

or coating.

  It is important to produce a good quality reel. It is possible for the feed roll to be stretched, creased, or torn during the rewinding operation, so

  that a roll intended for sale can become unsaleable.

  It is therefore necessary to produce a sellable rewind roll. The quality of the rewinding roller depends on the contact pressure exerted on it by the pressure cylinder or contact roll and the tension which is applied to the strip during its formation by the driving of the press roll,

  Rewinding roll core, or both.

  According to the present invention, the contact pressure between the press roll and the rewind roller can be precisely controlled. In order to stabilize the contact pressure between the press roll and the rewinding roll, it is essential to avoid the worst effects resulting from the mechanical vibrations of the rewinding machine. When the contact pressure is sufficiently controlled, there can be no air penetration between the surfaces of the strip to be wound. Therefore, it is possible to produce a rewind roll

  good quality, which is tightly wound.

  In order to obtain a tightly wound rewinding roll, the ratio of its weight and its volume must be maintained at a prescribed value in relation to its diameter or the length of the strip. According to our experimental data, the winding density of a roll obtained with a polyester film 8 to 14 microns thick, having a density of about 1.4, should

be from about 1.35 to 1.36.

  The slippage of the roll formed by the web on the core depends on the state of the surface of the web of sheet material. If the friction coefficient of the strip is low, as is the case for a silicon coated film, for example, there is a slip between the surfaces in contact. Otherwise, even if the coefficient of friction of the strip is large, as in the case of a base film of magnetic tape, slip easily occurs between the contacting surfaces of the strip when there is air penetration

between them.

  If, in operation, a large part of the rewinding machine vibrates, the effects on the pressure roll and the rewinding roll will occur in opposite directions. Depending on the vibration of the machine, the press roll will touch the rewind roller and move away from it repeatedly, so that there will be air penetration between the surfaces or layers of the tape to be wound. Thus, slip will occur between the contacting surfaces of the strip. If the web slides transversely, both sides of the rewind roller will be deformed. Otherwise, if the band slips

  longitudinally, the rewinding roller will be released.

  Slippage between the contacting surfaces of the strip will cause the formation of breaks and folds, and the roll thus produced will be unsalable. Recently, there has been a need for a machine to rewind at a high speed a very smooth web material. And, moreover, to rewind a band of great width, it is necessary to provide a machine

oversized.

  On the other hand, the user wants to obtain a rewinding roll of large diameter. The rewinding machine that is designed and manufactured to meet these requirements must be modified to avoid the worst

  effects due to mechanical vibrations during operation.

  The production capacity in rewinding rolls depends on the operation of the rewinding machine and, to improve it, it is necessary to leave the rewinding rollers as quickly as possible from the machine.

products.

  Japanese Patent No. 45-20644, corresponding to US Pat. No. 3,291,412, discloses one of the typical rewinding machines. The rewinding machine described in this publication comprises a plurality of pairs of rewind arms pivotally mounted at their inner ends, a plurality of rewind rolls carried by said arms at their outer ends to receive a strip of sheet material to be wound, a guide roller for each of the retracting rollers, a guide roller mounting means for pivoting it in one direction so that it is in contact on the periphery of each retracting roller, and a means for controlling the pressure contact between the guide roller and the rewinding roller. This machine is characterized in that a guide roll mounting means is provided such that peripheral contact with the roll of web material is maintained, the control means comprising means for controlling devices mounted on each of the mounting means for controlling the contact pressure

  between the guide roller and the rewind roller.

  The rewinding machine mentioned above may have the following disadvantages: Firstly, the support or pivot shaft of the rewinding arms is pivotally mounted on a main frame by means of a pair of bearings arranged at its ends and the main part of the rewinding machine is not properly fixed to the frame or chassis, so that it will tend to vibrate during operation. If the machine is large, the distance between the support ends of the shaft is increased and the rewind arms, which have to carry a heavy roll, must be mounted in a limited space on the long shaft. Therefore, it is difficult to improve the rigidity of the machine and to prevent

  mechanical vibrations during operation.

  Second, each rewind arm will change position depending on the change in width

  of the band to be divided and the change of the weight of the roll.

  And, moreover, the weight of the rewind roller will change

  with the change of its diameter and the weight of the band.

  In addition to this, the portion of the rewind arm carrying the rewind roller load is not supported securely and in operation the machine vibrates easily. The rewind arm moves by describing an arc, and the center of gravity of its pivot moves,

  so that the rewinding machine will produce vibrations.

  Not only the bearings of the shaft, but also a number of guide rollers of the belt, are mounted on the frame, and the vibrations of the frame due to the high rotation speed of said guide rollers can be transmitted to the arms of the shaft. support, rewinding arms and reels, and they may increase

during these transmissions.

  To transmit the driving force of a hydraulic cylinder to the rewinding arm, the length of a connecting arm between its pivot and its external end is smaller than that of the rewinding arm and, consequently, the displacement of the end external reel arm may be consequent, even if that of the end of the link arm is weak. Therefore, if a connecting piece between the hydraulic cylinder and a support, or a connection piece between the link arm and the hydraulic cylinder or the rewind arm pivot are worn, the latter will vibrate in operation. In the rewinding machine described in the aforementioned publication, it is impossible to precisely control the contact pressure between the roll of

  rewinding and the pressure roll.

  In this publication, it is clearly stated that even if the force applied by the press roll on the rewind roller is kept constant, the contact pressure between the two will vary during

rewinding.

  In the conventional rewinding machine, during rewinding, the contact pressure between the rewinding roller and the pressure roller varies because the direction of arrival of the web on the press roll is not maintained parallel to the direction

  arrival of the tape on the rewind roller.

  In addition, the line connecting the center of the pressure roll to the center of the arm pivot is inclined to the vertical, and the angle of inclination of the front press roll differs from that of the rear press roll. As a result, when the width of the band to be divided changes,

the contact pressure changes.

  Because of all this, it is impossible to order

exactly the contact pressure.

  Japanese Patent No. 55,293, published Jan. 7, 1980, discloses a web rewinding machine in which a roll carried on the support arms moves by pivoting as the rewinding roll is formed, the movement of the roll rewind being detected

  and the support arms held in a vertical position.

  According to this second publication, a plurality of rewind rollers, each supported by an independent support arm, are in contact with a common press cylinder via means

  application of pressure disposed on the support arm.

  The roll and / or the pressure roll are driven to rewind the divided web by a cutter on the rewind roll core. Each support arm is hinged to a common support means so as to be swingable against the common press cylinder within a certain range of small angles from its vertical position. The displacement of each of the support arms according to the increments due to the formation of the rewinding roller is detected, and the common support means returns to a horizontal direction through automatic control means. In this machine, however, there is a fault that produces vibrations when

of operation.

  In the rewinding machine shown in the second publication, since the support arm pivots about its lower end and the rewinding roller rotates at its upper end, in operation it will tend to vibrate easily,

  and it will be impossible to remove the vibrations.

  In the second publication mentioned above, it is written that to prevent the support arm from vibrating, it can be provided means for damping vibrations, such as an oil damper. However, in order to keep the contact pressure between the rewinding roller and the pressure roll at a relatively low value, with good accuracy, it is necessary to reduce the strength of the support arm against the oil damper. If the resistance against the movement of the rewinding arm is reduced, the effect to suppress the

  vibration of the support arm is lost.

  In the machine described in the second publication, both ends of a mounting beam of the core support means are supported in a raised position, and the core support means angularly moves to exit the rewind roller.

of the machine.

  In addition, it is very difficult to precisely control the contact pressure between the press roll and the rewind roller. Indeed, in this machine, the support arm tilts at a small angle from its vertical position and, to compensate for the change of contact pressure between the rewinding roller and the presser cylinder when said support arm is inclined from its vertical position, a pair of springs are provided between it and a support. In the inclined position, the support arm receives the weight of the rewind roller and its own

  weight to increase the angle of inclination.

  In this machine, the contact pressure between the rewinding roller and the press roll changes with the force that is applied by the roll of

  rewinding during its formation on the pressure roll.

  On the other hand, the force applied to the spring is

  kept constant, even if the support arm is tilted.

  Therefore, it is impossible to precisely control the contact pressure between the rewinding roller

  and the pressing cylinder by means of the spring.

  In case a roll is produced. heavy rewinding, from 10 to 20 kg for example, its weight changes as

  of its formation and the contact pressure also changes.

  Therefore, it is difficult to suppress the vibrations of the support means and to effectively control the contact pressure between the rewind roll and the press roll. Because of all this, the objects of the present invention are to provide: 1. a rewinding machine which can produce at high speed a good quality rewinding roll from a material of plastic sheet or very smooth paper; 2. a rewinding machine which can rewind a wide strip of material at high speed; and 3. a rewinding machine that can produce a roll

  rewinding of large width and large diameter.

  Still another object of the invention is to provide a rewinding machine in which a core supporting means operates without practically producing vibrations, and wherein the contact pressure between a press roll and a rewinding roll can functioning, to be permanently maintained at a

prescribed value.

  Still another object of the present invention is to provide a dividing and rewinding machine for webbing which can efficiently remove the rewinding roll. Other objects and features of the present invention will become more apparent to those skilled in the art,

considering the accompanying drawings.

  In the drawings, the same numerals denote corresponding parts in all the figures: FIG. 1 is a diagrammatic elevational view illustrating a first embodiment of a dividing and rewinding machine according to the present invention, FIG. 2 is a schematic plan view, partly in section, of the machine of FIG. 1, FIG. 3 is a schematic block diagram illustrating a contact pressure between a rewind roller -9 and a pressure roll, and a drive means for a distance adjusting means according to the present invention, FIG. 4 is a schematic diagram illustrating the relationship between a press roll and a rewind roll, according to the present invention, FIG. 5 is a schematic diagram explaining the relationship between a press roll and a rewind roll in a conventional rewinding machine, FIG. 6 is an elevational view of a second embodiment of the present invention, taken in the direction of the arrows, substantially along line VI-VI of FIG. 7, FIG. 7 is a schematic plan view, partially broken away to show the internal structure, of the machine of FIG. 6, FIG. 8 is a diagrammatic elevational view of a third embodiment of the present invention, and FIG. 9 is a schematic view illustrating a contact pressure between a press roll and a rewind roll, and a drive means of the distance adjusting means in the third example of

  embodiment of the present invention.

  In FIG. 1, which shows a first embodiment of the present invention, a dividing and rewinding machine 10 comprises a front portion 12 and a rear portion 14 which are of similar structures and operate in the same manner. A relatively wide sheet material feed belt W is guided through a plurality of guide rollers 16 between a feed roller, not shown, and a plurality of cutters or knives 18 disposed between

  the front portion 12 and the rear portion 14.

  The cutters 18 are well known per se, and each includes a roller 20 with grooves and a knife blade 21 which is slidably mounted on a guide beam 22 parallel to the longitudinal axis of the roller 20. The blade 21 may be chosen according to the thickness or nature of the W-band. To divide or cut the W-strip of sheet material into two or more sub-bands of equal or different widths CW1, CW2, ..., CWn , the blades 21 can be adjusted together for a prescribed width or

different widths.

  The neighboring sub-bands CW1, CW2,..., CWn pass alternately on guide rollers 24 of the part

  before 12 and rear 14.

  The front portion 12 and the rear portion 14 each have pressing rolls 26 and core carriers 30 carrying cores 28 on which the CW subbands are wound. The axial length of a press roll 26 may be selected to correspond to the width of the corresponding CW sub-band, and its longitudinal axis is mounted between a pair of support arms 32 in such a manner that it is parallel to the longitudinal axis of the corresponding core 28. Because one end of each support arm 32 is hinged to a movable support 34, and the longitudinal axis of the pressing cylinder 26, mounted on the other ends of two arms 32 , is parallel to the longitudinal axis of the core 28, the pressing cylinder 26 can press the rewinding roller R at a pressure controlled by appropriate means

such as a hydraulic cylinder 58.

  To mount a pressing roll 26 of a desired axial length between a pair of support arms 32, the supports 34 of the arms 32 can move or slide along the longitudinal axis of a guide beam 36 having both ends attached to the frame of the machine, not shown, and they can be fixed in a

desired position.

  The core supports 30 are provided with locking or clamping means for removably mounting the cores 28. A locking means may be selected from a plurality of existing types. The core supports 30 can be moved parallel to the longitudinal axis of the cores 28, so that each of them, the length of which is adapted to wind the corresponding CW subband, can be mounted between a pair of said supports. The core supports have a base 40 that is slidable along a distance adjusting member 42 and securely attached to a desired position. To rotate a core 28, so that the sub-band CW winds up therein, the core supports 30 are provided with a suitable drive device 44, such as an electric motor, for example, whose shaft output is connected via a

  transmission mechanism appropriate to the core 28.

  According to the present invention, in operation, as the diameter of the roll R increases, the core supports move, as a function of the increments of the roll R, in the direction of the arrow A in FIG. 1, and the cylinder 26 is applied to the roll R, with a pressure

  prescribed, without changing its position.

  For this purpose, a base 46, to which the distance adjustment means 42 is attached, can move on at least two rails 48 placed on a floor or a foundation frame. The heavy load base 46 moves continuously in the direction of arrow A in FIG. 1, from the winding start position in which the core 28 is in contact with the pressing roll 26, and as the diameter of the roll R increases due to the winding of the CW sub-band on the core 28. There are no pivot mounted parts in the core carriers 30, and the rotation of the roll

  rewind does not produce any vibration.

  In consideration of the installation work of the machine and the method of guiding the web W, a foundation structure 50 on which the rails are placed may consist of a steel block, in the form of a single plate thick, or in a formed structure

  by the meeting of a plurality of frame members.

  The base 46 comprises a plurality of support means or pads 52 which are provided to slide or move smoothly the base on the rail 48, without producing vibrations. For this purpose, conventional sliding mechanisms, linear pads, etc. can be used. Naturally, to support a heavy load, one can use wheels. If desired, the pads 52 may be attached to the foundation structure 50, and the rail 48 may be attached to the distance adjusting member 42. As shown in FIG. 2, a pair of rails 48 support the front and rear portions 12 and 14. In our experience, a pair of rails is sufficient to effectively support the rewinding machine, without vibrations occurring, in the case of two meters wide. For a band four meters wide, three rails are needed, and four for

a band 6 m wide.

  Between the foundation structure 50 and the base 46, drive mechanisms 54 are provided for moving the latter in the direction of the arrow A, FIG. 1. The mechanisms 54 may consist of a threaded shaft and an electric or hydraulic motor to make

turn said shaft.

  If it is necessary to provide movement of the distance adjusting member 42, it is desirable to use parallel movement mechanisms

classics.

  The dividing and rewinding machine according to the present invention is designed as follows: (1) The core supports are rigidly fixed, so that they do not produce vibrations in

operation.

  (2) The position of the core supports can be adjusted according to the width of the sub-band and the weight of the rewinding roll can be determined by its diameter and the weight of the web. In addition, the elements to carry a variable load are supported firmly, so that the rewinding machine does not produce vibrations. The machine can divide the weight of the rewind rollers according to the width change

Of the band.

  (3) As the diameter of the rewind roller increases, the core supports do not rotate or pivot, and therefore no vibration occurs. The rewinding roller can be mounted

at the lower level of the machine.

  (4) The frame of the front and rear part and the structure carrying the web guide rollers

can be separated.

  (5) In the conventional rewinding machine, at least three pivoting parts are provided for connecting a jack to a support, an arm to said jack and the core support to the frame, whereas in the present invention there is no need for

has none.

  Therefore, the present invention overcomes the disadvantages that have been reported about Japanese publication N 45-20644 mentioned above. In addition, the present invention makes it possible to avoid the disadvantages due to the formation of the rewinding roller at the upper end of the support arm that angularly turns around a pivot at its lower end, as shown by the Japanese publication.

  N 55-293 mentioned above.

  According to our experimental results concerning the operation of the dividing and rewinding machine of the present invention, it is possible to rewind a plastic strip 12 microns thick at a speed of 600 rpm, without vibration.

in no direction.

  It is very important to suppress the vibration of the core supports to effectively rewind the tape onto the core. In addition, it is necessary to precisely control the contact pressure between the cylinder

  presser and the rewinding roller.

  In the present invention, as explained above, in operation, the vibration prevention and the control of the contact pressure between the rewinding roller R and the press roll 26 are taken

into account.

  As shown in FIG. 3, to press a pressing roll 26 on a core 28 or a roll R with a prescribed pressure, each support arm 32 cooperates with a rod 56 which is actuated by means of the piston of a jack 58. The operation of the piston 60, whose stroke is weak, is controlled by the output signals

a control unit 62.

  It is best to move the core holders continuously in the direction of arrow A, Fig. 3, with the distance adjusting element 42, via the drive means 54 which will be actuated by output signals from the control unit 62. For this purpose, the displacement of the element distance adjustment 42 may be triggered by control signals indicating an increase in roll diameter

rewinding in formation.

  If it is desired to move step by step the pressure roll, with detection of its elementary movement, it is

  it is preferable that this movement be as small as possible.

  The order can be made by a system of

  digital or analog calculator.

  As previously explained, the press roll 26 and the rewind roll R can be moved linearly as the rewind roll is formed. Therefore, in the present invention, the control of the contact pressure between the press roll and the rewind roll will not be affected by the formation of the rewind roll, whereas until now this control of the contact pressure It was difficult because the rewind roller was pivoted on the support arm or rotated individually. According to the present invention, as shown in FIG. 4, the direction of the sub-band CW which arrives on a pressing roll 26 is always parallel to the direction of the sub-band CW which arrives on the rewinding roll R, and the center of the pressing roll 26 is kept in the same horizontal plane as the center of the reeling roller R. Therefore, the pressure to be applied to the pressure roller will not need to be

  changed because of the voltage variation of the band.

  In addition, since the support arm of the press roll is held in a vertical position, it is possible to ignore the

weight variation of said cylinder. On the other hand, in the conventional rewinding machine, according to for example the

  Japanese Patent No. 45 20664 already mentioned, as shown in FIG. 5, the direction of the sub-band CW arriving on a pressing roll T is not parallel to the direction of the sub-band CW which arrives on the reeling roll R. Even if they are parallel to the start, it is impossible to maintain the constant contact pressure during operation because the rewinding roller R rotates about the pivot P of its support S. According to the present invention, the operation of the press roll 26 can be controlled separately and

that of the core supports 30.

  It is possible to connect the jack 58 to a charge detector or load cell 64 to obtain the electrical signal indicating an instantaneous contact pressure between the press roll 26 and the rewind roller. Then, the signal can be sent back to the control unit 62 to improve the stability of the

operation.

  In our test, the dividing and rewinding machine of the present invention rewinds the plastic film strip 12 micron thick at 600 rpm under a contact pressure of 30 kg / m between the press roll and the roll. rewinding, and the contact pressure varies in a range of about 1/100 kg or less than 10 g per unit. On the other hand, in the rewinding machine

  conventional, the contact pressure varies from 500 g to 1 kg.

  So, the present invention allows to have a machine

re-winder very powerful.

  A second exemplary embodiment of a dividing and rewinding machine according to the present invention is shown in FIG. 6. In the machine 100, the guide rollers 16 of the web W and the cutters 18 are respectively arranged in the upper part of the machine, the web W being delivered to the cutters 18, by the guide rollers 16, from top of the machine. This type of machine is preferable to protect against dust. The base 46 and bench frame 102 are rigidly attached to the distance adjusting member 42 by welding, bolts and nuts, etc. These elements can increase the weight that is applied to the distance adjustment element 42, and improve

the prevention of vibrations.

  As shown in FIG. 7, the distance adjusting member 42 moves in the longitudinal direction of the web W, along four rows of rails 48, so as to distribute the load applied to it on each of these rails. The distance adjusting member 42 can be moved smoothly in the longitudinal direction of the W-band only, the other movements being excluded. According to the present invention, it is possible to adapt the machine according to the

width and weight of the band.

  In the second embodiment of the present invention, the drive mechanism 144 providing the reciprocating movement of the distance adjusting member 42 in the longitudinal direction of the web W is carried on one end of the rail 48 supporting the base 46 and the distance adjusting member 42. The drive mechanism 144 has threaded shafts 106 engaged in pads 104 attached to the distance adjusting member 42, a servo motor 108 rotating the threaded shafts 106 at low speed, a motor rotating the threaded shafts 106 at high speed in order to facilitate the movement of the element 42 when the machine is ready to operate or when the rewinding rollers are removed. the machine, a spur gear 112, a drive shaft 114 and idler sprockets 116. A pair of threaded shafts 106 are driven simultaneously, and the distance adjuster 48 with the s 28 nuclei can be moved together

  or spaced apart from the pressing rollers 26.

  In the dividing and rewinding machine according to the second embodiment of the present invention, the rewinding rollers R can be easily removed from the machine, automatically

and in no time.

  In the conventional rewinding machine, the rewinding rollers are inclined with the core support arms, so as to place them on the table or to raise them.

with hooking means.

  On the other hand, in this embodiment, there is a gap between the press rolls 26 and the front or rear part, where it is possible to place means 150 for removing or conveying the rolls of

  rewinding in the direction of their axis.

  Each conveying means 150 comprises a belt conveyor 152 actuated by a driving device, not shown, an elevator 154 and a drive 156. If desired, the elevator 154 can be moved by appropriate means, not shown, in a direction perpendicular to the axis of the rewinding roller R. When the front portion 12 and the rear portion 14 of the machine 100 are in the rewinding phase, the conveyors 152 are moved away from their working position. When the rewinding phase -18-- is completed, the conveyors 152 are put into service for

  take out the rewinding rollers R from the machine.

  In the second embodiment of the present invention, it is preferable to extend the upper portion of the core supports 30 inward, so as to install the conveyor devices 150 in the middle of the machine. If desired, a trolley or wagon can be used as conveying means 150. According to the present invention, it is possible to fix the pressure roll and to press the roll of

  rewinding R against it, if desired.

  In the first and second exemplary embodiments of the present invention, the pressing cylinders 26 are respectively intended for each of the roll cores

rewinding 28.

  In contrast, in the third embodiment, FIG. 8, a single pressing cylinder 226 is mounted in each of the front and rear portions 12 and 14,

  regardless of the number of rewind rolls.

  To press the pressure roll with a controlled pressure on a plurality of rewinding rollers R, the core supports 30 can slide along a base 240, without causing vibrations relative to

to this one.

  In this embodiment, as shown in FIG. 9, there is provided means 260 for controlling the contact pressure between the rewinding rollers R and the press roll 226, and means 262 for controlling the movement of the press fit member 226.

distance 42.

  In practice, the control signal of the control means 260 is applied to a pressure control means 238, so as to support the core supports 30 on the pressing roll 226 at a prescribed pressure. As the rewinding roller R is formed, the distance adjusting means 42 is actuated by the control means 262 so that it moves to the position corresponding to the position of the supports

of core on the base 240.

  In the third embodiment of the present invention, it is possible to place the conveying devices between the front part and the rear part. -20-

Claims (4)

  A web-dividing and rewinding machine comprising a plurality of guide rollers (16) for guiding a wide feed belt (W) to a cutter (18) which divides the web (W) into narrow longitudinal subbands (CW1, CW2, ..., CWn), a front portion (12) and a rear portion (14) disposed facing each other for winding said narrow sub-strips as rewind rolls (R). ) on cores (28) for each of them, and means for alternately feeding said subbands to said front portion (12) and said rear portion (14), characterized in that it comprises: - supports core members (30) provided in each of the front and rear portions (12, 14), pressure rollers (26, 226) mounted such that they press the rewinding rollers (R) to a prescribed pressure, - distance adjusting elements (42) arranged parallel to the longitudinal axes of said rewind rolls t (R), on which said core supports (30) are mounted, - drive means for moving said core supports (30) with said distance adjusting elements (42), only in the longitudinal direction of said sub-bands, and - means for controlling said drive means according to the increases in   diameter of said rewinding rollers (R).   2) Dividing and rewinding machine according to claim 1, characterized in that a plurality of pressing rollers (26) are each associated with a rewinding roller of each sub-band (CW1, CW2, ..., CWn) , the contact pressure between each pressing cylinder (26) and the corresponding rewinding roller being controlled.   -21- 3) A machine dividing and rewinding machine according to claim 1, characterized in that said pressure rollers (226) are fixed, the contact pressure between said pressing rollers (226) and said rewinding rollers (R) being controlled by small   displacing said core supports (30).   4) A dividing and rewinding machine according to claim 1, characterized in that the upper parts of said core supports (30) have inward extensions on which are mounted   said rewinding roll cores (28).   A dividing and rewinding machine according to claim 1, characterized in that means (150) for pulling out the rewinding rollers are placed in the space between said front portion (12) and said rear portion (14).