Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1998-04-02
2002-06-25
Mayes, Curtis (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S205000, C156S210000, C156S356000, C156S358000, C118S258000
Reexamination Certificate
active
06409857
ABSTRACT:
RELATED APPLICATIONS
This application depends for priority on German Application No.: 197 15 174.4, filed Apr. 11, 1997
FEDERALLY FUNDED RESEARCH
N/A
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is in the field of corrugated composite sheet manufacture.
2. Background Art
The invention concerns a device for manufacturing a composite sheet comprising at least one corrugated sheet and at least one flat sheet that is glued to the wave peaks of the corrugated sheet, said device comprising at least one fluted roller for shaping and/or maintaining the shape of the corrugated sheet, said roller being covered with the corrugated sheet around a portion of its circumference during operation, and a gluing unit for applying a liquid glue used to attach the corrugated sheet to the flat sheet, with said gluing unit having a gluing roller whose outer surface is continuously coated with a glue film and whose axis is essentially parallel to that of the fluted roller, said gluing roller being driven at approximately the same peripheral speed as that of the fluted roller, and with it being possible, using means for moving the rollers closer together, to move said gluing roller, with its outer surface against the portion of the circumference of the fluted roller that is covered with the corrugated sheet, into a close-up position that allows the glue to be transmitted to the wave peaks of the corrugated sheet, thus forming a gluing gap.
For example, this type of device is used for the manufacturing of corrugated cardboard, particularly one-sided corrugated cardboard. In this case, a cardboard or paper sheet is moved between a pair of fluted rollers and stamped into a corrugated sheet. After the corrugated sheet passes through the stamping gap formed between the two fluted rollers, it is pressed against the fluted roller that comes after the stamping gap in the direction of the corrugated sheet using appropriate means, e.g., by creating excess pressure in the space surrounding the fluted rollers and the gluing roller, and moved past the gluing roller, at which point glue is transmitted from the gluing roller to the wave peaks of the corrugated sheet.
In conventional devices, the width of the gluing gap between the gluing roller and the fluted roller opposite it is adjusted so that the wave peaks of the corrugated sheet are immersed in the glue film applied to the gluing roller without coming into contact with or being pressed flat against the surface of the gluing roller. Thus, there is always a gap between the wave peaks of the corrugated sheet and the outer surface of the gluing roller. Ordinarily, the thickness of the glue film is in the range of 0.15-0.40 mm. Accordingly, in the case of conventional devices for the manufacturing of corrugated cardboard, the gluing gap between the gluing roller and the fluted roller must be precisely adjusted. Specifically, on the one hand, the gluing gap must not be too wide in order to ensure that the wave peaks of the corrugated sheet are actually immersed in the glue film. On the other hand, in the case of conventional devices for manufacturing corrugated cardboard, an excessively narrow gluing gap should be avoided in order to prevent the wave peaks of the corrugated sheet from being pressed against the outer surface of the gluing roller.
One possibility for precise adjustment of the width of the gluing gap lies in having an operator hold a test band of a known preset thickness (such as 0.07 mm) between the fluted roller covered with the corrugated sheet and the gluing roller.
The gluing roller is then gradually moved closer to the fluted roller. This operation is carried out with both the fluted roller and the gluing roller rotating. The gluing gap is made smaller and smaller until the operator feels tugging on the test band. In this manner, the actual gap between the gluing roller and the wave peaks of the corrugated sheet lying on the fluted roller is adjusted to the thickness of the test band (for example, 0.07 mm). However, such adjustment of the gluing roller has the disadvantage that it is only possible to adjust the gap width of the gluing gap once before the corrugated cardboard manufacturing device is actually put into operation, and it is not possible to verify or readjust this width during operation. In addition, it is dangerous for the operator to hold the test band between the rotating gluing roller and the running corrugated sheet. As soon as the operator feels tugging on the test band, he/she must immediately let go of the test band to avoid getting his/her fingers caught in the gluing gap. In the case of so-called one-sided machines for the manufacturing of one-sided corrugated cardboard, in which the corrugated sheet is held against the fluted roller by excess pressure, this kind of adjustment of the gluing gap is not possible. As the gluing unit with the gluing roller is located inside a pressure chamber in such one-sided machines, with said chamber necessarily being under excess pressure during operation of the machine so as to hold the corrugated sheet against the fluted roller, the operator can only gain access the gluing gap when the pressure chamber is opened and therefore not under pressure. In this case, however, the corrugated sheet does not remain against the fluted roller, thus making it impossible to adjust the gluing gap using a test band.
In addition, the method is known of adjusting the width of the gluing gap by means of sensory positional measurement. In one method, a non-contact distance sensor is attached to the frame of the gluing unit immediately next to the gluing roller, with said sensor measuring the distance to a target point on a bearing support of the fluted roller. The measurement value given by the distance sensor thus indicates the width of the gap between the frame of the gluing unit and the bearing support of the fluted roller in the area of the distance sensor. Another method consists of attaching a distance sensor to the frame of the gluing unit in the same manner, but with a smooth band attached outside the fluted area of the fluted roller being taken as the target point for distance measurement.
In a third method, the position of an adjustable stop, against which the gluing unit is pressed for specified adjustment of the width of the gluing gap, is determined by means of an appropriate sensor, such as a rotation angle indicator or a position sensor. Any displacement of the stop and thus the width of the gluing gap manifests itself in a corresponding change in the measurement signal emitted by the sensor. Thus the position of the stop is an indicator of the width of the gluing gap.
What the above three measurement methods have in common is that direct measurement of the gluing gap, whose width is the actual parameter of interest, does not take place. Rather, in all cases, distance or positional measurement takes place outside of the gluing gap. It has been found that the distance or positional measurement values obtained by such methods to not provide sufficient data on the actual width of the gluing gap. On the one hand, the measurement conditions at the various measurement sites may differ from conditions in the area of the gluing gap. On the other hand, under the prevailing operating conditions in a corrugated cardboard manufacturing machine, the available distance or position sensors operate relatively inaccurately, with the result that it is necessary to check the measurement device at regular intervals, and in some cases, to recalibrate it.
The above problems in measuring the gluing gap are further aggravated by the temperature conditions prevailing in the environment of this gap. In a corrugated cardboard manufacturing machine, the fluted roller and the press roller, which is used to press the glued corrugated sheet together with a flat sheet, are heated by steam. The heat is absorbed by the paper sheets, i.e., the corrugated sheet and the flat sheet. The flow of heat depends on various parameters, including the thickness of the paper, the amount of glue, the running speed of
Pallas Dieter
Schulz Jens
Vonderheiden Jorg
Friedman Allen N.
Mayes Curtis
McCarter & English LLP
Peters Machinenfabrik GmbH
Purvis Sue A.
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