Coating apparatus – Immersion or work-confined pool type – Work-confined pool
Reexamination Certificate
1998-12-04
2001-10-02
Lamb, Brenda A. (Department: 1734)
Coating apparatus
Immersion or work-confined pool type
Work-confined pool
C118S419000, C118S325000, C118S123000, C254S0930HP
Reexamination Certificate
active
06296703
ABSTRACT:
FIELD OF THE INVENTION
My present invention relates to a pneumatic actuator, especially for controlling the transverse profile of a coating device in an apparatus for coating of paper or cardboard webs having elements spaced across the width of the web and which can be adjusted to regulate that transverse profile or coating cross section.
BACKGROUND OF THE INVENTION
For the coating of paper or cardboard webs with viscous coating materials or coating materials which are applied by doctoring or jet coating, especially pigmented materials, sizings and the like, it is important to provide the coating apparatus with the ability to control the cross section of the coating applied, i.e. the transverse profile, both in terms of the basis weight (weight per unit area of the coating) or the thickness thereof. For that purpose a row of adjusting elements may be provided across the width of the web which can control the local basis weight or thickness so that the result of effective positioning of these elements individually is control of the transverse profile. Usually the goal is to eliminate variations in the transverse profile which may result in the production of the coated web and the goal is to insure a uniform coating.
In the coating of paper or cardboard webs, so-called doctor blade apparatuses may be provided in which an excess of the coating material, for example a coloring matter, in a viscous form is applied and the excess is doctored off by an elastic doctoring blade which can also be referred to as a shaving or scraping blade and which removes that excess, leaving a uniform coating. The level of the basis weight of the coating remaining on the web can be adjusted by locally varying the pressing force of the blade against the coating on the web. The blade can thus be backed by a bendable bar upon which the setting elements act.
Such a doctor blade arrangement is described in WO 93/17795 and here the flexible bar is provided with a row of setting elements for adjusting locally varying pressing forces. Each setting element comprises an axially-shiftable rod or pin guided in a holder and positionable by a set screw against the force of a compression spring. The compression spring, the screw and the rod act axially.
In DE-OS 44 32 177, a so-called free jet nozzle applicator is disclosed which utilizes a slit nozzle formed between two lips from which a free jet of the coating material is directed against the web or an applicator roller which applies film of coating material formed on that roller to the web. To adjust a certain transverse profile of the coating of the two lips of the slit nozzle may be yieldable and can be adjusted differently in different zones over its length relative to the other lip. The adjusting elements are adjusting screws spaced apart across the width of the web, prestressed by spring elements. The actuation of the adjusting screws is effected either manually or by means of servomotors or the like.
OBJECTS OF THE INVENTION
It is the principal object of the present invention to provide n improved actuator for a setting element utilizable in a coating apparatus whereby drawbacks of earlier systems are avoided.
Another object of the invention is to provide a system for controlling the transverse profile of a coating, in a coating apparatus, which utilizes structurally simple, reliable and accurately controllable actuators and wherein the actuators have highly reproducible effects with minimum hysteresis.
It is also an object of the invention to provide an improved actuator for use in a coating profile controlled arrangement of the latter type.
SUMMARY OF THE INVENTION
These objects and others which will become apparent hereinafter are attained, in accordance with the invention in a pneumatically-operated actuator which can comprise:
a frame;
a pair of generally parallel, mutually spaced apart sheet-metal spring plates in the frame and secured to the frame at one side of the plates;
a pin longitudinally shiftable in the frame and secured to an opposite side of the pair of plates;
a pneumatic cushion formed between the plates and connectable to a source of compressed air whereby pressurization of the cushion deflects the plates transversely, thereby longitudinally shifting the pin; and
a spring on the frame yieldably counteracting transverse deflection of the plates.
Preferably the pin is guided through a seat for the spring which, advantageously is a coil compression spring braced between these seats and a plate on the pin so that the spring biases the pin axially outwardly with respect to the frame.
To minimize friction between the cushion and the spring plates, a low friction foil may be interposed between the cushion and each plate.
The displacement of the pin can be measured by a displacement-measuring device which directly monitors the axial stroke of the pin or by a measuring device which is a response to deflection of one of the plates
The actuator is preferably used as one of a multiplicity of such actuators in an apparatus for coating a web, especially of paper or cardboard, which has a corresponding number of control elements disposed across the path of the web and positionable to vary the basis weight or profile of the coating applied to the web. The device may include a doctor blade which removes excess material from the coating and which is backed by a bendable member upon which the control elements act, the control elements being spaced apart along this bendable member. The bendable member in turn, acts upon the doctor blade. Alternatively, the control element can act upon a flexible lip of a slit nozzle of the type described.
REFERENCES:
patent: 3800569 (1974-04-01), Wilcox
patent: 4665859 (1987-05-01), Dunlap
patent: 32 20 075 (1983-12-01), None
patent: 38 34 719 (1990-04-01), None
patent: 43 34 556 (1995-04-01), None
patent: 44 33 048 (1996-03-01), None
patent: 295 20 686 U (1996-05-01), None
patent: 296 10 773 U (1996-10-01), None
patent: 195 32 920 (1997-03-01), None
patent: 195 38 861 (1997-04-01), None
patent: 196 17 458 (1997-06-01), None
patent: 296 22 365 U (1997-07-01), None
Dubno Herbert
Jagenberg Papiertechnik GmbH
Lamb Brenda A.
LandOfFree
Pneumatic actuator, especially for controlling a basis... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pneumatic actuator, especially for controlling a basis..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pneumatic actuator, especially for controlling a basis... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2616350