Paper making and fiber liberation – Apparatus – Running or indefinite length product forming and/or treating...
Reexamination Certificate
2001-11-20
2004-06-08
Chin, Peter (Department: 1731)
Paper making and fiber liberation
Apparatus
Running or indefinite length product forming and/or treating...
C162S374000
Reexamination Certificate
active
06746576
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for attaching at least one shaped part, together with a wear part onto a support piece and to an arrangement for mounting at least one shaped part which is equipped with a wear part, onto a support piece.
2. Description of the Related Art
An arrangement of this type is known from the German prior art document DE-OS 1 761 174, which discloses the mounting of an oxide ceramic strip (shaped part/wear part) to a strip shaped support (support piece). The support piece may be manufactured from metal or a hydrophobic, deformation resistant synthetic material such as sintered low-pressure polyethylene. The oxide ceramic strip is longitudinally movable and flexible for expansion and is equipped for this purpose with a longitudinal groove extending along the entire length thereof. The groove enlarges toward the inside to a T-shaped cross section. The support is provided with several longitudinal slots distributed along its length, whose orientation is in a longitudinal direction. The longitudinal slots intersperse the support from its flat cover surface on which the floor area of the oxide ceramic strip rests, through to a longitudinal groove on the floor area of the support. A screw intended for securing the oxide ceramic strip on the support can slide in each longitudinal slot. The oxide ceramic strip has profile flanges which point toward the inside. A shim facilitates the screw head resting on such profile flanges. A nut is fastened onto the screw, whereby the nut with the help of springy shims, for example two Belleville washers, supports itself on a shim which rests on the oxide ceramic strip. If the oxide ceramic strip expands differently than the support, then the screws glide in the longitudinal slots, a process further facilitated by the springy shims. Since the fastening elements which secure the oxide ceramic strip on the support engage the oxide ceramic strip from the bottom, the surface of the oxide ceramic strip interacting with the wire and felts remains completely smooth, thereby neither increasing the friction resistance nor causing countersink holes for the fastening screws in the surface in which stock particles could accumulate.
A disadvantage of this arrangement including fastening elements (for example, screws) is, that the fastening elements may loosen during operation and, in a worst case scenario, may independently detach themselves. A detached fastening element may get into the processing zones of the paper, cardboard or tissue machine and may cause considerable damage, resulting in a forced shut-down of the machine and possibly in expensive repairs.
Further, such replacement of the wear part together with the shaped part results in longer down times because of the multitude of fastening elements which would normally require unscrewing, tightening and securing. Furthermore, an easy change-over of the wear part, together with the shaped part, is not possible from the machine side since the fasteners are mounted at more or less equal distances in the CD (cross-machine direction) direction and must be actuated at their installation locations.
Existing arrangements are already known from the PCT document WO 93/00473 and the two German documents DE 43 19 311 A1 and DE 37 17 532 A1 in which the shaped part is held and fastened by a dovetail connection, a T-groove connection or a cross connection in the support piece.
Because of the required manufacturing tolerances on the one hand, and the required clearances between the shaped part and the support piece on the other hand various problems can occur. A fit which is too tight makes the mounting of the shaped part more difficult and makes it impossible to slide the long shaped part onto the support piece. Many times, disassembly of a shaped part with too tight a clearance is not possible without destroying the wear piece mounted on it. On the other hand, too much clearance between the shaped part and the support piece leads to wobbling of the shaped part on the support piece, resulting in that no defined dewatering geometry (e.g., foil angle) can be adhered to. Furthermore, too large a clearance may cause vibration of the parts which, in the area of the former, may lead to formation problems in the material web which is to be formed.
SUMMARY OF THE INVENTION
It is therefore the objective of the invention to improve a method and an arrangement of mounting at least one shaped part, which is equipped with a wear part, onto a support piece in such a way that the aforementioned disadvantages of the state of the art are avoided. A prime aspect is the realization of an improved cost-effectiveness ratio. With respect to the method of the present invention, two parts are clamped to each other by a clamping device so that an operating tolerance is vastly or preferably totally eliminated based on manufacturing tolerances; and a quick and non-destructive change-over of the shaped part is possible; and a common sealing of the two parts (support piece and shaped part) by the clamping device on the one hand and a positive locking of the two parts on the other hand provides that neither fiber-loaded nor dirt-loaded processing water can penetrate between them. This type of clamping provides an excellent way of realizing the advantages of increased effective operating time, a defined and constant dewatering geometry and low change-over times.
Furthermore, clamping is achieved by the clamping device in a manner whereby vibrations are eliminated and the clamping becomes oscillation damping, whereby a “softer” and low-noise machine operation is achieved.
A defined and constant dewatering geometry is also facilitated if clamping by the clamping device is achieved in a manner whereby the foil angle during clamping is not changed.
From a statistical point of view, it is advantageous if clamping is achieved so that, in addition to the clamping device's clamping line, at least two additional defined support lines ensure clear positioning between support piece and shaped part.
With respect to the apparatus of the present invention, the shaped part displays a contour, specifically an inside contour extending along the entire length of the under side thereof, this contour is essentially complimentary to the outside contour extending along the entire length on the top of the support piece, and a preferably operable clamping device is provided in the area of the two complimentary contours.
The clamping device provides that the two parts are definitively and permanently clamped to each other, whereas the complementing contours provide that, even in the event of a clamping device malfunction, the basic operation thereof is maintained, so that there is no increased danger of wire and/or felt destruction.
In a first embodiment of the invention, on the first side, the shaped part has a 2-part T-groove as an inside contour and on the second side has a 2-part dovetail groove as an inside contour; and on the first side the support piece has a 2-part T-rib as an outside contour and on the second side has a 2-part dovetail rib as an outside contour; and the clamping device is located in the area of the angled 2-part dovetail contour.
In a second embodiment of the invention, the shaped part has a T-groove as an inside contour, preferably with a recess in the groove bottom; the support piece has a T-rib as an outside contour; and the clamping device is mounted preferably in the center in the area of the grooved bottom.
In a third embodiment of the invention, the shaped part has a T-groove as an inside contour, preferably with a recess at the groove bottom; the support part has a T-rib as an outside contour; and the clamping device is mounted preferably centered on the T-rib and will act upon the T-groove, preferably in the area of the groove bottom.
In a fourth embodiment of the invention, the shaped part has a dovetailed groove, equipped with a parallel base as an inside contour, preferably with a recess in the grooved bottom; the support piece has a dovetaile
Haase Christoph
Halmschlager Günter
Keinberger Rüdiger
Leitner Johann
Simmel Rudolf
Chin Peter
Taylor & Aust P.C.
Voith Paper Patent GmbH
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