The present invention relates to a method according to the preamble of claim 1 for transferring rolls of paper, board and cellulosic web in a roll packaging system during wrapper winding, label attachment and header placement.
The invention also relates to an assembly for implementing the method.
The papermaking industry generally uses a packaging method wherein inner headers are first placed on the ends of a roll to be packaged, whereupon a wrapper is wound about the roll and finally the outer headers are placed on the roll ends. The packaging cycle and system themselves can be implemented in different ways and, typically, the packaging system is tailored to the needs of the mill. Inasmuch as the roll widths vary in a wide range, the wrapping method of the roll wrapper must be selected to meet the wrapping capacity needs. If an extremely high packaging capacity is required, wrapping stations can be used equipped with plural wrapper rolls of different widths of which a suitable wrapper can be selected for any roll to be packaged. However, this kind of wrapping station is very costly, whereby within the capacity limits of the station it may be more cost-advantageous to use, e.g., wrapping by overlapping layers, whereby two or more parallel wrapper courses are wound about the perimeter of the web roll. This kind of wrapping technique can be implemented using one or two wrapper widths thus allowing a very simple station layout. A disadvantage herein, however, is that either the roll being wrapped or the wrapping station itself must be moved during wrapping so as to allow the parallel wrapper courses to be wound.
In the above-mentioned overlap wrapping, the paper, board or cellulosic web rolls to be packaged are wrapped using a wrapper narrower than the roll to be wrapped. As the wrapper width is not sufficient to cover the entire perimeter width of the web roll, the roll is packaged by winding plural parallel wrapper turns thereabout. For such parallel overlap wrapping on a web roll, either the roll or the wrapper car or both must be moved parallel to the longitudinal axis of the roll. One technique of implementing the roll transfer is to move the roll being packaged on the cars of an intermittent-motion indexing conveyor. The indexing conveyor has separate stations for each packaging step: roll entry, buffer, wrapping, labeling and placement of outer headers, whereby one indexing conveyor car is located at each one of the stations. The car or cars are reciprocatingly moved between the stations so that after a car has moved a roll to the next station, the car is returned to its “home” position to be ready to receive a new roll to be transferred. To move the rolls forward, the indexing conveyor of the car(s) is moved upward, whereby the rolls thereon are elevated from the support rollers or support means of the station. As the car of the conveyor system has a fixed construction or, alternatively, the indexing car conveyor is comprised of cars connected together and moving in synchronism, all rolls are moved simultaneously. A roll transferred in this kind of system to the wrapping station is positioned by the movements of the indexing conveyor. Such a positioning of the web rolls at the wrapping station is unproblematic provided that the wrapper rolls with their feed assemblies are adapted movable at the wrapping station. However, if the wrapping station structures are stationary, lateral transfer of the roll at the wrapping station causes substantial time loss in overlap wrapping. Namely, the roll must be moved laterally in the direction of its longitudinal axis for winding the adjacent wrapper courses. Herein, an indexing conveyor is obviously problematic, because it forces all of the web rolls to move at the transfer of web roll being wrapped. Hence, after the completion of overlap wrapping of a roll, all the other rolls must be relocated back to their center positions at their respective stations by the movements of the indexing conveyor, which is a retarding step in the cycle time. While this may not necessarily drawback if only a small number of rolls are to be overlap wrapped, the roll sizes vary widely in modern papermaking mills, whereby the transfer movements of the indexing conveyor may give rise to a substantial reduction of available packaging capacity.
It is an object of the present invention to provide a method offering an improvement to the operating speed of a packaging system using an indexing conveyor.
The goal of the invention is attained by arranging the loading surface of at least one car at a given station, e.g., the car positioned at the wrapping station, to rise to a level above the loading surface elevations of the other cars and, further, adapting the indexing conveyor to operate using at least four different elevations, or vertical positions of the conveyor.
More specifically, the method according to the invention is characterized by what is stated in the characterizing part of appended claim 1.
Furthermore, the assembly according to the invention is characterized by what is stated in the characterizing part of appended claim 7.
The invention provides significant benefits.
By virtue of the invention, the operating speed of a packaging system in the overlap wrapping of rolls can be increased with extremely simple arrangements. A separate center positioning of rolls after the completion of the overlap wrapping step of a roll becomes redundant, whereby the overlap-wrapping-related lengthening of cycle time remains as minimal as the cumulative wrapping time due to the winding of the two or three adjacent wrappers. Inasmuch as the positions of rolls at other stations than the wrapping station remains stationary, the positioning of the other rolls remains accurately at the set coordinates. The mechanical constructions needed in the implementation of the invention are uncomplicated and require only actuators controllable to at least four different elevation levels. With the help of the lowermost elevation level, the transfer of the indexing conveyor car back to the receiving station can be accomplished even when a roll already resides on the station. The lowermost elevation level is set such that at all stations the rolls are situated higher than the top surface of the indexing conveyor car at each respective station when the conveyor car has been driven to the lowermost elevation level. In addition to this lowermost elevation level, the conveyor may have three, four or even a greater number of elevation levels. In conventional packaging systems, however, it appears that generally maximally four elevation levels are needed. The transfer of rolls to the receiving station is more secure when a deeper space is provided between the support rollers.
In the following, the invention is examined in more detail with the help of the appended drawings in which
Referring to
At the receiving station 5, a roll to be placed on the conveyor is positioned differently depending on whether the roll shall be wrapped into a single wrapper or whether it needs overlap wrapping, whereby plural adjacent wrapper courses must be wound thereon. For this position operation, the receiving station 5 is provided with a parallelogram mechanism suited to elevate and lower the roll in regard to the indexing conveyor car 4. Respectively, the wrapping station 7 must have equivalent means for moving one roll without simultaneously causing uncontrolled movement of other rolls. To this end, the top level of the car 4 is elevated at the wrapping station to a higher position in regard to the car top level elevation at the other stations. Additionally, each station is provided with support rollers or support means on which the rolls can be lowered in situations requiring the indexing conveyor car 4 to be moved, e.g., during the return movement of car 4, without disturbing the positions of the other rolls. The positioning of the rolls at the stations can be performed in either a centered or offset fashion. In the present text, centered positioning refers to a roll position having its center point in the lateral dimension of the roll being aligned with the centerline of the station, while offset positioning refers to any roll position having the roll center point shifted into an offset position from the centered position.
Next, the invention is discussed in greater detail with the help of
Next, the indexing conveyor car is raised by two steps to the second elevation level 2, whereby all rolls 1013 located at stations 58 are elevated upward with the exception of roll 14 situated at the pressing station 9 for attachment of roll headers. At this moment, the roll 14 residing at the pressing station must be ejected or the pressing station must already be empty. Next, the indexing conveyor car is transferred forward, whereby all the rolls resting on the indexing conveyor are transferred forward. After the transfer step, rolls 1013 are lowered onto their support means and the indexing conveyor car is moved backward. At this moment, the roll 10 to be overlap wrapped is situated in an offset position at the buffer station 6 and the other rolls 11-13 are in centered positions at their respective stations. This sequence leaves the conveyor in the situation of
The above-described cycle is reinitiated when a roll to be overlap wrapped enters the receiving station 5.
The receiving station can be equipped with a loading/elevating apparatus based on a parallelogram mechanism such as is disclosed in Canadian patent no. 2,003,605. If the capacity need is not excessively high requiring the maximally fast operating speed, the arrangement shown in
In the above text, a system has been described comprising five separate roll handling stations. Obviously, the number of roll handling stations can be varied according to the number of roll packaging and handling stages required in the system. However, the minimum system layout capable of implementing the method according to the invention comprises at least a receiving station, some other station and a wrapping station. The number of stations following the wrapping station is unessential to the implementation of the invention inasmuch as the rolls leave the wrapping station in a centered position. If the number of stations is only two, the arrangement according to the invention is unnecessary. While the offsetting transfer of rolls required at the stations may be carried out at any station preceding the wrapping station, in practice this step is most advantageously carried out at the receiving station. The car of the wrapping station can be a single, contiguous car or, alternatively, it may comprise a number of connected and thus jointly moving separate cars. A roll to be overlap wrapped may be offset positioned already at the centering station 18 preceding the receiving station. Then, no offset movement is needed at the buffer station, but instead, the roll can be loaded at the base level 0 directly onto the car and no movement of the car is required for offset positioning of the roll. However, offset prepositioning of the roll can be carried out at any station when the conveyor is operating at its base level 0. Alternatively, the roll may be taken to the wrapping station ready centered, whereby the roll end is positioned at the wrapping station for the first wrapping stage before starting wrapping. The operating strategy is selected so that the system gives sufficient and optimal packaging capacity in a particular operating environment. The elevated portion of the car may also be situated elsewhere than at the wrapping station if a need arises at some other station to move the rolls in their longitudinal direction. In certain cases, narrow rolls must be transferred during labeling if multiple labels must be attached at their center line. In the case that transfer operations between the stations are substantially different from each other, it may be necessary to use a greater number of four in the elevation levels, e.g., five or six. However, the lowermost elevation must always be such that allows the indexing conveyor car to move freely at each one of the stations whether rolls are loaded thereon or not. The next elevation level to the lowermost one is such that allows the transfer of a roll resting on at least one station without the need for moving at least one other roll. The need for other elevation levels is dictated by the local roll transfer criteria.
Number | Date | Country | Kind |
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20051040 | Oct 2005 | FI | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/FI2006/050442 | 10/13/2006 | WO | 00 | 4/11/2008 |