Brushing – scrubbing – and general cleaning – Attachments – Moving surface scraper – wiper – or brush
Reexamination Certificate
1999-06-03
2001-03-20
Till, Terrence R. (Department: 1744)
Brushing, scrubbing, and general cleaning
Attachments
Moving surface scraper, wiper, or brush
C101S169000, C162S281000
Reexamination Certificate
active
06202252
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a doctoring apparatus of the type employed in the processing of paper, textiles and other industrial products.
BACKGROUND OF THE INVENTION
In known doctoring apparatus, a doctor blade has a working edge that is applied to a rotating surface of an elongated cylinder. The working edge of the doctor blade removes materials from the rotating surface of the cylinder. The doctored materials to be removed may consist of a sheet or web being processed in a papermaking machine, or the doctored material may consist of contaminates accumulating on the surface of the cylinder.
Doctoring apparatus typically comprise a blade carrier assembly which is adapted to hold the doctor blade in operative engagement with the surface of the rotating cylinder to be doctored. The blade carrier assembly is mounted about a pivoting axis where the angle of the blade and pressure associated with the blade contacting the surface is controlled by two flexible walled tubes located on either side of the pivoting axis. The blade carrier assembly is mounted directly to a doctor back and the doctor back is positioned within the papermaking machine across the width of the cylindrical surface to be doctored. In some instances, the doctoring apparatus extends from 3 to 8 meters in width across a cylindrical roll.
The doctor blade is removably mounted in the blade carrier assembly. This permits the removal of the doctor blade for cleaning. However, maintenance of the blade carrier assembly is not as simple because it is not possible to remove the blade carrier assembly from the doctor back. Thus maintenance of the blade carrier assembly requires having to maintain the blade carrier assembly from within the machine which is difficult and cumbersome.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a doctoring apparatus where the blade carrier assembly is removable from the doctor back to permit for easier maintenance of the doctor blade assembly.
The present invention relates to a doctoring apparatus for doctoring a cylindrical rotating surface. The doctoring apparatus has a doctor blade for doctoring the cylindrical surface. The doctor blade is carried by a blade carrier assembly that holds the doctor blade. The blade carrier assembly further has at least one moveable tenon suspended from the assembly. The apparatus further includes a doctor back having a supporting surface over which the blade carrier assembly is adapted to slide. The supporting surface has at least one mortise. The mortise is sized to loosely receive the tenon to permit the tenon to slide along the mortise as the blade carrier assembly is slid over the supporting surface so as to couple the blade carrier assembly with the doctor back. The doctoring apparatus has an adjustment mechanism which is carried by the blade carrier for moving the tenon into a locking engagement with the mortise so as to releasably secure the blade carrier assembly to the doctor back. Thus, the present invention provides the novel aspect of allowing the blade carrier assembly to slide relative to the doctor back and for the adjustment mechanism to lock the blade carrier assembly relative to the doctor back.
In the preferred aspect of the present invention, the tenon is carried by the blade carrier assembly and the mortise is carried by the doctor back. It is within the realm of the present invention to have the tenon carried by the doctor back and the mortise located in the blade carrier assembly.
Preferably, one mortise extends laterally across the doctor along a longitudinal axis that is parallel to the axis of the cylindrical rotating surface. This structure allows the blade carrier assembly to be slid across the doctor back and located in place. Alternatively, more than one such mortise and tenon combination can be located on each of the respective doctor back and blade carrier assembly. Also, the mortise may be located extending in from the sidewall of the doctor back and not necessarily extending completely across the width of the doctor back. It is envisaged that the mortise can extend in the doctor back orthogonally of the axis of rotation of the cylindrical surface. Further, the tenon preferably comprises one bar suspended from the blade carrier assembly and alternatively may comprise a series of spaced apart blocks in the shape of a tenon suspended in spaced apart locations along the blade carrier assembly.
In the preferred construction, the blade carrier assembly includes outer and inner spaced apart plates that are adapted to support the doctor blade. The inner plate is adapted to slide over the supporting surface of the doctor back and at least one tenon is supported from the inner plate. The adjustment mechanism is carried by the blade carrier assembly and includes at least one bracket having a bearing secured to the inner plate. A pivoting rod is secured to the outer plate and is journalled in the bearing of the bracket. A pair of flexible walled tubes are positioned between the spaced apart plates on either side of the bracket to form part of the adjustment mechanism. The tubes, once pressurized, further separate the plates to adjust the relative position of the doctor blade with respect to the cylindrical rotating surface. In so doing, the bracket is pulled away from the supporting surface to cause local deflection of the lower plate away from the doctor back. This results in the tenon moving into a locking engagement with the mortise.
In accordance with an aspect of the present invention there is provided a doctoring apparatus for doctoring a cylindrical rotating surface. The apparatus comprises a doctor blade for doctoring the cylindrical surface and a blade carrier assembly for holding the doctor blade. The blade carrier assembly includes one of at least one moveable tenon and at least one mortise. The apparatus further comprises a doctor back having a supporting surface to which the blade carrier assembly is adapted to be mounted. The supporting surface includes one of the other of the at least moveable tenon and the at least one mortise. The at least one mortise is sized to loosely receive the tenon to permit the tenon to slide into the mortise as the blade carrier assembly mounted onto the supporting surface so as to couple the blade carrier assembly with the doctor back. The apparatus further includes an adjustment mechanism carried by a selected one of the doctor back and blade carrier assembly for moving the tenon into locking engagement with the mortise to releasably secure the blade carrier assembly to the doctor back.
REFERENCES:
patent: 4367120 (1983-01-01), Hendrikz
patent: 4665859 (1987-05-01), Dunlap et al.
patent: 4906335 (1990-03-01), Goodnow et al.
patent: 5178731 (1993-01-01), Kivimaa et al.
patent: 5269846 (1993-12-01), Eskelinen et al.
patent: 5279710 (1994-01-01), Aikawa
patent: 5417761 (1995-05-01), Bernert
patent: 5980692 (1999-11-01), Goodnow et al.
patent: 2043842 (1995-06-01), None
Till Terrence R.
Valmet Ltd.
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