Winding – tensioning – or guiding – Unwinding – With attachment to preceding material
Reexamination Certificate
2001-12-07
2003-10-07
Jillions, John M. (Department: 3654)
Winding, tensioning, or guiding
Unwinding
With attachment to preceding material
C242S552000, C242S555500, C242S554400
Reexamination Certificate
active
06629664
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a flying reel-changer in a web-fed rotary printing machine, with which a reel change can be carried out during standstill operation or during crawl operation of the web-fed rotary printing machine.
Flying reel changers are known in the prior art and are used in web-fed rotary printing machines—that is to say in printing machines in which the paper web to be printed is unrolled from a feed reel and is supplied to the printing units for the printing operation. In a web-fed rotary printing machine, a flying reel changer is used for connecting the web start of a new paper reel to the outgoing reel during the continuous printing operation of the printing machine, without interrupting the running paper web, when the paper supply on the outgoing old paper reel approaches its end.
The disadvantage in the flying reel changers disclosed by the prior art is that a flying reel change can be carried out only during the continuous printing operation of the printing machine, but not during standstill or crawl operation, at which the printing material web is moved at only a few centimeters per second.
However, such a change from the outgoing old paper reel to a new paper reel can be desirable in the case of specific print jobs. For example, if a preceding print job has been completed and only a small quantity of paper still remains on the old paper reel, the next reel change would be required soon. In such a case, there is the risk that when the printing machine at is run up again at the start of the new print job, web breaks can easily occur because of web tension fluctuations associated with a reel change and arising from the complicated dynamic control operations.
In addition, an early change from the old paper reel to a new paper reel during standstill operation or during crawl operation of the printing machine can be required if different paper grades or web formats are processed during the preceding print job and the following print job.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a flying reel changer and a method of joining the start of a paper web of a new reel to an old paper web which overcomes the above-mentioned disadvantages of the prior art apparatus and methods of this general type. In particular, it is an object of the invention to provide a flying reel changer in a web-fed rotary printing machine, in particular in a web-fed rotary offset printing machine for newspaper printing, with which a reel change can be carried out even during standstill operation of the printing machine, with high reliability and in the shortest possible time.
With the foregoing and other objects in view there is provided, in accordance with the invention, a flying reel changer for joining the beginning of a new paper web of a new paper reel to an outgoing old paper web of an old paper reel that is led over a dancer roll. The flying reel changer has first drive means that, during the standstill of the printing machine or during the crawl operation of the same, rotates the new paper reel at a minimum splice speed. The device further includes second drive means which accelerates the old paper reel, which is at a standstill or moving at crawl speed, that is to say at a circumferential speed in the range of 0.1 m/s, for example, to a speed which substantially corresponds to the minimum splice speed. In order to accommodate the sag in the paper web which occurs in this case, the dancer roll is moved or moves in the corresponding direction, preferably at the same time that the old paper reel is accelerated to the splice speed, in such a way that a substantially uniform tension is maintained in the old paper web in the region of the reel changer. The actuating means can advantageously be formed by a pneumatic cylinder, which is fed from a compressed air source with a preferably large capacity, and which inserts a constant and preferably substantially position-independent force on the old paper web. The device according to the invention further includes joining means, which joins the old paper web and the new paper web to each other while the paper webs are moving at the minimum splice speed and while the dancer roll is being moved by the actuating means.
The flying reel changer provides the advantage that the splicing operation, that is to say sticking the beginning of the web of the new paper reel to the old paper reel, can be carried out during standstill or during the very slow crawl operation of the printing machine, at which the printing machine is generally moved only centimeter by centimeter. In this way, after a print job has been completed, as early as the preparation phase for the new print job, that is to say, for example, while changing the printing plates, the old paper reels can be replaced at the same time, without having to put the printing machine into a printing operation at a high continuous printing speed in order to replace the old paper reel. This is particularly advantageous when there is only a small supply of paper on the old outgoing paper reel which, when the printing machine is run up again for a print job, would lead to a flying reel change as the machine was being run up. Numerous control parameters, which change dynamically, have to be monitored by the central open-loop and closed-loop control device, in particular when the printing machine is being run up.
A further advantage is that, in the event of a format change between a preceding print job and a new job, the new paper reel or reels for the other format can be changed automatically at a standstill, while, for example, the printing units are being fitted with new printing plates.
In accordance with an added feature of the invention, the first paper reel is first accelerated by the first drive means, which can be, for example a controlled-position and/or a controlled-speed electric motor, to a minimum synchronization speed, and is then rotated, preferably for a certain time, for example, a few seconds, at this minimum synchronization speed. Then, the new paper reel is braked down, for example by braking means, for example, a known disc brake, or else by means of suitably energizing the first drive means, from the minimum synchronization speed to the minimum splice speed. This results in the advantage that the minimum splice speed can be reached and regulated with increased accuracy and in a comparatively shorter time than is possible in the case of accelerating the new paper reel directly up from a standstill.
In order to keep the travel of the dancer roll as small as possible, which has preferably been moved into its zero position at the start of the reel change, that is to say at the end of the preceding print job, in accordance with a further embodiment of the invention, the second accelerating means can accelerate the old paper reel only when the new paper reel has reached the minimum splice speed. In the same way as the first accelerating means, the second accelerating means can preferably be driven by a controlled-position and/or a controlled-speed electric motor.
The joining means preferably includes a pressure roll, which presses the old paper web onto the new paper roll after the old paper reel and the new paper reel have been moving for a certain time, for example, for one to two seconds, at the minimum splice speed. The new paper roll is provided with an adhesive section, for example, a double-sided adhesive tape to adhere to the old paper web.
In accordance with an additional feature of the invention, the joining means includes a pressing device formed as a pressure roll, a brush roll, or a brush strip.
Pressing the old paper web onto the new paper reel, which is provided with an adhesive section at the beginning of the paper web is advantageously carried out as a function of the position of the new paper reel. The position of the new paper reel is determined using one or more sensors, which detect markings applied to the new paper reel. The markings can be, for example, metal strips or colored marki
Heidelberger Druckmaschinen AG
Jillions John M.
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