Patent Application
20070102564
The present invention is directed to roll changers and to methods for performing a flying roll change A roll changer for supplying a web of material has at least two receivers. One of these supports an unwinding web of material. The other supports a fresh roll for use in a flying roll change.
Roll changers are typically employed in printing presses and are used for supplying the web of material used as the material which is to be imprinted. In this case, paper webs are typically used as the material. The web of material is initially wound on a roll of material and rolls off this roll of material.
So that upon the depletion of a roll of material, the entire printing press need not be stopped, it is generally known to perform a so-called flying roll change. For this purpose, a new roll of material, on whose outer layer of material appropriate gluing spots, for use in accomplishing a connection with the web of the roll of material which is running out, have, for example, been prepared, is placed into the roll changer. During of the flying roll change, the fresh web of material is then accelerated to a circumferential speed corresponding to the web speed of the established roll of material. In the course of the actual web change, the start of the web of the fresh roll of material is connected with the web of material on the roll of material which is running out, and the web of material on the roll of material which is running out is cut at substantially the same time. In this way, the start of the web of the fresh web of material is drawn into the printing press by the old web of material and a stoppage of the press is avoided.
Depending on the remaining thickness of the web of material on the roll of material which is running out, and in particular depending on the web's width and the tube core diameter, the web of material running out has a continuously changing inherently critical resonating number of revolutions.
With relatively large web widths, and in particular, with web widths of, for example, >3,600 mm, and with very high web draw-off speeds, such as, for example, with web draw-off speeds of 15 m/s, critical vibration conditions can arise in the web of material which is running off when the remaining web gets below a defined remaining thickness, because of vibration excitations in the range of the inherently critical resonating number of revolutions. To prevent these critical vibrating conditions, it is often necessary to reduce the web speed when the remaining thickness of the web falls below a minimum. Such application cases result in that either the web of material cannot be completely used, in order to prevent such critical vibrating conditions, or that the web draw-off speed must be reduced during the roll change. Printing costs are increased in an undesired way by both steps.
FR 2 076 474 shows a single receiver for rolls of material. Two rows of clamping jaws are arranged one behind the other.
DE 36 27 533 A1 describes a roll carrier. A support is placed against an unwound roll.
DE 100 56 274 A1 discloses a mandrel with two rows of clamping jaws which are arranged one behind the other. The diameter of the one row can be changed from 150 to 160 mm, and the diameter of the other row can be changed from 70 to 80 mm.
Devices for unwinding rolls are known from EP 0 441 152 A2, EP 0 708 047 A1 and EP 0 413 890 A1. Each of these has support journals with movable clamping jaws.
U.S. Pat. No. 3,891,158, U.S. Pat. No. 5,360,502, U.S. Pat. No. 5,316,230, U.S. Pat. No. 3,836,089 and U.S. Pat. No. 4,100,012 describe methods for roll changing.
The object of the present invention is directed to providing roll changers and to providing methods for performing a flying roll change.
In accordance with the present invention, the object is attained by the provision of a roll changer for supplying a web of material. The roll changer includes receivers which support at least one unwinding web of material and at least one fresh web of material. The fresh web of material is in a roll that has been prepared for a flying roll change. Both rolls of the webs of material are rotatably supported in the roll changer. Each roll is held by two receivers. Each such receiver has a support journal with clamping jaws.
The present invention is based on the basic premise of reducing the freely vibrating length of the unwinding roll of material. This is done in order to influence the inherently critical resonating number of revolutions of the unwinding roll of material in the desired way.
In the course of the employment of the roll changer in accordance with the present invention, a reduction of the freely vibrating length between the clamping points of the web of material being unwound at the roll changer takes place. A support device is provided, which support device is brought into engagement with the circumferential surface of the unwinding roll of material. It is possible, in accordance with the present invention, to considerably reduce the freely vibrating length by the use of this additional support of the roll of material between the clamping points. If, for example, the support device is brought into engagement with the circumferential surface of the unwinding roll of material exactly in the center of the roll between the clamping points, the vibrating length is halved in this way, and the inherently critical resonating number of revolutions is correspondingly displaced upwardly. In this case, the support device is arranged in such a way that it can be brought to rest against the circumferential surface of the unwinding roll of material when the unwinding roll of material is arranged in the position which is provided for the flying roll change. The critical vibrating conditions of the unwinding roll of material occur, in particular, shortly before the depletion of the web of material with the depleting roll having a relatively small thickness of web material remaining. A support of the unwinding roll is thus required, in particular, in the phase of the unwinding operation which immediately precedes the roll change.
The specific way in which the support device is configured is somewhat arbitrary, as long as a sufficient support of the unwinding roll of material is assured, for use in reducing the vibrating length. In accordance with a preferred embodiment of the present invention, the support device has at least one revolving support belt, which belt can be pressed against the circumferential surface of the unwinding roll of material. This support belt can be seated on rollers, for example, and will rotate at a speed which corresponds to the circumferential speed of the unwinding roll of material.
Depending on the type of application to which the roll changer is subjected, it can be useful to greatly reduce the freely vibrating length. This can be achieved because several of these support devices can be provided, and which several support devices come to rest against the circumferential surface of the unwinding roll of material side-by-side and spaced apart from each other. In that case, the freely vibrating length corresponds only to the respective distance between two adjoining ones of the support devices, or to the distance of the first support device, or of the last support device, from the clamping points of the unwinding roll of material. As a result, it is thus possible to change the freely vibrating length of the unwinding roll of material in any arbitrary manner.
The support device can be provided in a manner which is particularly simply if the support device does not have its own drive mechanism. In this case, the support device can itself be driven by the unwinding roll of material by the transfer of frictional forces. To the extent that such frictional forces are employed for driving the support device, the support device should preferably be produced from a wear-resistant material with a large coefficient of friction in the area of a contact face of the support device with the roll of material.
Alternatively, it is also within the scope of the present invention for a drive mechanism to be provided on the support device, by the use of which drive mechanism, the support device is being driven. For example, an electric motor can be provided for this usage, by the use of which electric motor one of the bearing rollers for seating the support belt is driven. By an appropriate control of the drive mechanism, it becomes possible, prior to bringing the support into contact with the roll of material, to accelerate the support to a speed which is synchronized with the circumferential speed of the roll of material. In this case, it is possible to avoid the occurance of an undesired slippage between the support device and the circumferential surface of the unwinding roll of material, or to avoid the formation of breaks in the material web, when the support belt is placed against the roll of material.
In many cases, the employment of the support device is desired only during defined phases of the operation of the roll changer, and in particular during the phase directly prior to the flying roll change. For this reason, it is particularly advantageous if the support device is seated so that it is movable between at least two functional positions. The first functional position corresponds to the actual position of employment or use, in which the support roller comes into contact with the circumferential surface of the unwinding roll of material and appropriately supports the roll of material. The second functional position corresponds to a position of rest, in which the support device is not in contact with the unwinding roll of material.
The specific manner in which the support device is attached or is supported, in relation to the roll changer, can basically be accomplished in any arbitrary manner. In accordance with a first embodiment of the present invention, the support device is fastened on the roll stand of the roll changer. This has the advantage that the support device will be moved along when the roll stand is pivoted. There is thus no relative movement between the support device and the appropriately assigned roll of material when the roll support is pivoted. With this embodiment, it is, in particular, possible that the support device can be brought to rest against the unwinding roll of material prior to the roll of material being arranged in the position that is required for a flying roll change. The unwinding roll of material is thereby also supported by the support device in the course of the pivoting of the roll stand, and is also preferably supported prior to the web of material being accelerated from a stop. Contact with the support belt takes place simultaneously.
To accomplish this preferred embodiment of the present invention, the support device can be fastened between two support arms of the roll stand. The two support arms also support the appropriately assigned roll of material.
Alternatively to this first preferred embodiment, the support device can also be fastened on a base that is located underneath the position of the unwinding roll of material which is intended for a flying roll change. As a result, the support device is not an integral component of the roll changer. This embodiment is of particular advantage if the support device is able to be lowered into the base. In its position of rest, in which the support device has been lowered into the base, the support device does not constitute an obstacle.
In order to be able, if necessary, to control or to regulate the support process of the unwinding roll of material by the employment of the support device, at least one sensor which is usable for measuring a support parameter, such as, for example, the actually expended support force, or the belt tension of the support belt, can be provided. A cooperatively provided control device, or a correspondingly employed control circuit, can process the results of the measurement provided by the sensor and can control, or can regulate, the support device in accordance with a predetermined desired value.
The employment of the support device in accordance with the present invention offers particularly significant advantages in connection with its use with roll changers in which rolls of material of a width of greater than or equal to 3,600 mm are processed. Webs of material of such widths are used, in particular, in connection with rotogravure imprinting in rotary rotogravure printing presses. The high printing speeds used in such rotogravure printing lead to the previously mentioned problems with inherently critical resonating numbers of revolutions.
In accordance with the method of the present invention, for operating the novel roll changer, the support device is brought to rest against the unwinding roll of material prior to the arrangement of the unwinding roll of material into a position that is suitable for a flying roll change. In the course of a pivoting of the roll stand, for arranging the unwinding roll of material in a position that is suitable for a flying roll change, the support device remains in engagement with the unwinding roll of material. This assures that the unwinding roll of material is also supported during the pivoting process of the roll stand. As soon as the roll stand has reached an end position, in which the unwinding roll of material takes up a position that is suitable for a flying roll change, the support device will remain in engagement with the unwinding roll of material until the flying roll change has been completed and the old roll of material can then be appropriately braked.
A support device can be provided for usage other than for the reduction of the freely vibrating length, or preferably in connection with it. The prevention of inherently critical resonating numbers of revolutions can also be improved because the freely vibrating length of the unwinding roll of material can be reduced by the use of longer mandrels.
To allow the longer mandrels to provide a sufficient clamping force on a contact face with the interior circumference of the core of the unwinding roll of material, it is proposed that at least two clamping jaws be arranged, one behind the other, on the mandrel and extending parallel with the axis of rotation of the support journal. Because of this increase in the number of the clamping jaws it is possible to apply a great clamping force. Accordingly, in addition to the reduction of the clamping length, the quality of the clamping is also increased by increasing the clamping rigidity such as by an increase of the clamping factor, or the chuck factor.
In the absence of a central support, paper widths of more than 4,000 mm, and in particular of 4,300 mm, and cores/sleeves of a diameter of 150 mm, do not allow the accomplishment of a dependable roll change at speeds of webs of material of more than 15 m/s when using the cores which presently are customary in the industry. Without the use of a support, and with such long sleeves it is possible to attain speeds of the web of material of maximally 12 m/s.
In the present invention, several clamping jaws, which adjoin each other in a row of clamping jaws, and which are, in particular, evenly spaced from each other, are preferably distributed over the circumference of the support journal. In a preferred embodiment of the present invention, two rows of clamping jaws are arranged on the mandrel in the axial direction of the mandrel, each row having eight clamping jaws which are arranged in the circumferential direction. This results in highly secure clamping of the roll of material on the mandrel.
Preferred embodiments of the present invention are represented in the drawings and will be described in greater detail in what follows.
Shown are in:
A first preferred embodiment of a roll changer 01 for use in feeding in a web 02 of material, and in particular for use in feeding a paper web, to a printing press, which is not specifically represented, is schematically represented in
In the process state represented in
As soon as the roll stand 04 has been moved into the position represented in
The freely vibrating length of the unwinding roll 06 of material, which is the distance between the receivers 05, is shortened because of the contact pressure of the support belt 12 against the circumference of the unwinding roll 06 of material. The inherently critical resonating number of revolutions of the roll 06 of material is displaced into a non-critical range of the number of revolutions by this length shortening.
A second preferred embodiment of a roll changer 16, in accordance with the present invention, is represented in
In contrast to the first embodiment of the roll changer 01 depicted in
Support belts 22 are provided on the respective support devices 17 and 18. These support belts 22 can be brought into contact with the circumference of the roll 06, 07 of material to be supported. Pneumatic actuating cylinders 21 are provided for use in bringing the support belts 22 into and out of contact. By extension and retraction of these pneumatic actuating cylinders, the seating structure of the support belts 22 can be moved or pivoted.
The following actions are taken prior to a flying roll change being performed by the roll changer 16 shown in
As soon as the unwinding roll 06 of material has been unwound down to a remaining thickness, which makes a roll change inevitable, the unwinding roll 06 of material is pivoted into the position where it is located to the left of the pivot shaft 03. This is done by pivoting the roll stand 04 and results in the orientation represented in
After the unwinding roll 06 of material has reached the gluing position, or loading position, to the left of the pivot shaft 03, as represented in
The support device 17, 18 can be placed against the fresh roll 07 of material, while it is still stopped, and therefore rests against it during acceleration. Accordingly the support device 17, 18 can be embodied without a drive motor.
A support journal 24 of a mandrel 05 is represented in cross section in
A length l10 of the core 10 of the roll 06, 07 of material, which is resting on, and which is held by the clamping jaws 26 of the support journal 24, is more than 4000 mm, and in particular is more than 4200 mm. A wall thickness b10 of the core 10 is more than 10 mm, and in particular, it is greater than 15 mm. A core wall thickness b10 of more than 17 mm, and in particular one which is greater than 20 mm, is particularly advantageous. An interior diameter d10 of the core 10 is 150.2±0.2 mm.
Alternatively to, or in concert with the steps for reducing the free clamping length of the roll of material, a determination of the web speed and/or of the diameter of the leftover roll during a flying roll change can take place for performing the flying roll change.
As previously described, a first web of material 02 of an unwinding roll of material 06 to be changed, which runs at a first web speed, is connected with a second web 29 of material of a fresh roll 07 of material, which second web 29 runs at a second web speed, during the flying roll change. Prior to connecting the first web 02 of material with the second web 29 of material, the first web speed is reduced to a second web speed, so that during the connecting process, the first web 02 of material has the second web speed.
It is also possible, prior to the connection of the webs 02, 29 of material, to determine a minimum diameter of the unwinding, soon to be leftover roll 06, as a function of a width b02 of the web 02, 29 of material, which determines at what time the two webs 02, 29 of material must be connected with each other at the latest.
In another preferred embodiment of the present invention, the second web speed, which is set during the connection, is determined as a function of the properties of the material of the core 10 of a roll 06, 07 of material.
In other preferred embodiments, geometric dimensions regarding the core 10 of the roll 06 of material, such as, for example, the size of the interior diameter d10 of the core 10, or the wall thickness b10 of the core 10, determine the reduced web speed of the first roll 02 of material during the connection.
In a further preferred embodiment, the second web speed, which is preset for the connecting process, is fixed by the geometric dimensions of the receiver 05, and in particular by the geometric dimensions of the support journal 24. It is also possible to fix the reduced web speed as a function of the length l26 of the clamping jaws 26 of the support journal 26.
The reduction of the web speed, together with the connecting process, is controlled by a program.
Equipping the roll stand 04 with the fresh roll 07 of material, and removing the depleting roll 06, takes place with the aid of a pushcart 31, such as, for example, a scissors-type lifting platform 31, as represented in
The new roll 07 of material is transported to the roll changer 01 by a transport cart 32 that is pulled by a chain. There, the transport cart 32 with the roll 06 of material stored on it, enters the lifting platform 31 on the level ground. Wheels 34 have been attached to the transport cart 32, by the use of which wheels 34, a movement of the transport cart 32 inside the scissors-type lifting platform 31 is made possible. The scissors-type lifting platform 31 moves into a centered position and lifts the new roll 07 of material to approximately 1600 mm above ground level. Thereafter, the center roll 07 of material is brought into the position in which it is placed on the shaft of the roll stand 04. When the position for placement on the shaft has been reached, the signal “advance sleeve” is issued to the roll stand 04. The receivers 05 with the support journals 24 are moved into the new roll 07 of material. Once the receivers 05 with the support journals 24 have been inserted into the new roll 07 of material and the clamping jaws 26 have been spread open, the scissors-type lifting platform 31 is lowered by issuing the signal “roll placed on shaft” and is moved into its base position.
In the course of the roll change, following the roll revolution, the support device 11 moves against the unwinding, depleted roll 06 of material and stabilizes it in its center. In response to the command “advance cutter” the unwinding web 02 of material is cut off the depleted roll 06 of material and is stopped by means of the shaft motor of the roll stand 04. As already previously described, the stopping process of the depleted roll 06 of material is aided by the support device 11 of the scissors-type lifting platform 31. The support belt 12 is pivoted away, and the scissors-type lifting platform 31 moves into its loading position for loading a fresh roll 07 of material.
In the meantime, as seen in
A schematic plan view of the roll changer, with various stages of roll supply, is represented in
While preferred embodiments of a roll changer and a method for carrying out a flying roll change, in accordance with the present invention are set forth fully and completely hereinabove, it will be apparent to one of skill in the art that various changes in, for example, the specific type of web of material, the drive motors and the like could be made without departing from the true spirit and scope of the present invention which is accordingly to be limited only by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 103 56 028.9 | Dec 2003 | DE | national |
| 20 2004 005 645.3 | Apr 2004 | DE | national |
This patent application is the U.S. National Phase, under 35 USC 371, of PCT/EP 2004/052176, filed Sep. 15, 2004; published as WO 2005/054101 A2 on Jun. 16, 2005, and claiming priority to DE 103 56 028.9, filed Dec. 1, 2003 and to DE 20 2004 005 645.3 filed Apr. 8, 2004, the disclosures of which are expressly incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP04/52176 | 9/15/2004 | WO | 5/31/2006 |
