Patent Publication Number: US-6705216-B2

Title: Calender

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority under 35 U.S.C. §119 of German Patent Application No. 101 29 102.7, filed on Jun. 16, 2001, the disclosure of which is expressly incorporated by reference herein in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a calender with at least one roll stack having a maximum of three rolls arranged to form at least one nip limited by two rolls, and with a stand arrangement featuring a stand at each axial end of the roll stack. The rolls are supported on the stand with the aid of antifriction bearings. 
     Such a calender, which is also called a “soft calender,” is used mainly in paper production. Since it features only one or two nips per roll stack, it is particularly suitable as a machine calender which can be used in-line, i.e., directly following a paper machine. 
     2. Discussion of Background Information 
     A known calender of the type mentioned at the outset features an essentially perpendicular (vertical) standing roll stack with two rolls, with both rolls being arranged in an L-shaped stand. This embodiment has the advantage that both rolls can be dismantled and installed with the aid of a crane, thus also the lower roll. 
     However, it has been shown that the L-stand is not suitable for higher operating speeds and larger widths. Experience shows that there is a risk of vibration problems at speeds of over about 1200 m/min and widths of over about 7 m. 
     In order to take higher speeds into account, a U-shaped stand has been used in which there are stand columns both on the front and on the back of the roll stack. This stand construction is not open at the front or at the back of the roll stack, so that dismantling the bottom roll is possible only by extending the bottom roll out via the face, i.e., axially. Since this procedure requires that an assembly space be kept free next to the calender, i.e., an assembly space that corresponds at least to the length of the roll, considerable space is required. 
     SUMMARY OF THE INVENTION 
     The present invention provides a soft calender which can be operated at a high speed and with which a roll change is easily possible. 
     According to the instant invention, the stand of the calender of the type mentioned at the outset includes a bearing edge on which the antifriction bearings are arranged and which is tilted at an angle to a vertical reference in a range of about 30° to 60°, a contact edge on which the stand stands on a mounting surface and which extends beneath the bearing edge, and a connecting edge forming a connection between the bearing edge and the contact edge. Further, the bearing edge, the contact edge and the connecting edge are connected by a plate. 
     The instant invention contemplates a roll stack tilted at an angle, i.e., inclined to the vertical. A preferred angle of tilt is about 45° which, however, can be changed within the scope of the values given above. As a result of the instant structural arrangement, a partial load alleviation, i.e., the specific weight of the upper roll no longer acts on the line load in the nip to the full extent. However, there is still a vertical roll weight component that leads to a minimum load on the antifriction bearings, so that its play does not lead to increased vibration behavior of the rolls. Due to the tilt, the rolls of the roll stack can again be handled by a crane, i.e., to be dismantled and/or installed. Despite these easy possibilities for changing a roll, a high operating speed and a large working width are rendered possible by the special construction of the stands. The stands have a very wide bearing surface that is the result of the contact edge supporting the bearing edge over its entire length. This support is implemented by a plate so that no hinge points or other connection points are formed between the contact edge and the bearing edge that could be distorted in a critical way. Thus, the plate provides the stand with an extraordinarily high degree of rigidity. Although the stand extends further in the flat (horizontal) direction due to the tilt of the bearing edge relative to the vertical, the total height is reduced. 
     The plate can include openings as needed for assembly or maintenance purposes. However, as a whole, it may be preferable that the plate be formed as an essentially flat form which accordingly provides a high mechanical stability. The rolls can be supported in a leverless manner, i.e., they can either be displaced parallel to the bearing surface or they can be rolls with jacket lift. 
     The plate preferably includes a thickness of at least about 150 mm, and more preferably of at least about 200 mm. The choice of a relatively “thick” plate has several advantages: high mechanical stability results, and a sufficiently large area is available in the bearing edge to provide mounting openings for the antifriction bearings or to other attachment parts. A stand embodied or formed in this way is considerably more rigid than previously known stands, which utilized columns and tie-bars to form a box-frame construction, i.e., by welding together in box form comparatively thin metal sheets with a thickness in the range of about 20 mm. 
     The plate is preferably formed by a sheet metal that essentially includes a triangular shape. The term “sheet metal” is intended to also cover metal plates with the above-mentioned thickness range according to the invention. Such a triangle is easy to produce, since only a few cuts are necessary to determine the triangular shape. Furthermore, it results in a pleasing appearance. 
     Here it is particularly preferred for the triangle to feature capped points, so as to keep the required construction space small, while also saving other material. In this regard, it is assumed that the points of a triangle do not contribute much to the stability of the stand, but instead represent a risk of forming oscillatory parts. 
     The triangle is preferably embodied or formed, e.g., as a right-angled triangle, in which the hypotenuse forms the bearing edge. In this manner, the construction space required for the stand can be kept as small as possible. Further, the contact edge is shorter than the bearing edge. In the illustrated embodiment, the connecting edge is vertically oriented so that it can be used as an orientation surface or edge for attachment parts requiring a vertical orientation. 
     Two roll stacks are preferably provided, and each stack includes a plate-like stand with an essentially triangular shape with connecting edges substantially vertically oriented at each axial end. Moreover, the two roll stacks may preferably be positioned adjacent to one another. This arrangement of two roll stacks is known per se, and makes it possible for the material web to first rest with its first side on a hard roll and with its opposite second side on a soft roll, i.e., a roll with an elastic or resilient surface, while in the next roll stack the conditions are exactly reversed, i.e. the second side rests on the soft roll and the first side on the hard roll. Of course, it is also possible to use only rolls with the same type of surface in each roll stack. If the connecting edges are substantially vertically oriented and the stands placed mirror-inverted or mirror-symmetrical to each other, the stands can be positioned with a relatively small distance between them, thereby keeping the required construction space small. 
     The present invention is directed to a calender including at least one roll stack having a plurality of rolls arranged to form at least one nip, a stand arrangement having a stand located at each axial end of the at least one roll stack, and antifriction bearings arranged to support the plurality of rolls on the stand arrangement. Each stand includes a bearing edge on which the antifriction bearings are arranged, a contact edge structured and arranged to contact a mounting surface, and a connecting edge forming a connection between the bearing edge and the contact edge. Each stand further includes a plate structured and arranged to include the bearing edge, the contact edge and the connecting edge to one another. 
     In accordance with a feature of the instant invention, the bearing edge can be tilted at an angle between about 30° to 60° from a vertical reference, and the bearing edge can be arranged to extend under an entire extent of the bearing edge. 
     According to another feature of the invention, the plurality of rolls may include a maximum of three rolls. Further, the plurality of rolls can include two rolls. 
     The plate can have a thickness of at least about 150 mm, and preferably has a thickness of at least about 200 mm. 
     Moreover, the plate can be composed of a metal sheet. The metal sheet may be formed in a triangular shape, and the bearing edge can be oriented at an angle between about 30° and 60° with respect to a vertical reference. The triangular shape may have at least one truncated point. Further, the triangular shape can include an right-angled triangle, and the hypotenuse of the right-angled triangle may form the bearing edge. Still further, the right-angled triangle may include an isoscolese right-angled triangle. 
     The plate can be formed in a triangular shape, and the bearing edge may be oriented at an angle between about 30° and 60° with respect to a vertical reference, and the triangular shape can include a right-angled triangle, and the hypotenuse of the right-angled triangle can be arranged to form the bearing edge. 
     In accordance with a further feature of the invention, the plate can be composed of a right-angled triangular metal sheet arranged such that the hypotenuse of the right-angled triangular element forms the bearing edge. 
     Each the plate can be formed with a thickness sufficient stand on the contact edge and to support the plurality of rolls without additional support elements. 
     Further, the at least one roll stack can include two roll stacks and each roll stack may be is supported on a separate stand arrangement. Each the plate of each stand arrangement may be triangularly shaped and the connecting edges of each stand arrangement can be substantially vertically oriented and positioned adjacent the connecting edges of the other stand arrangement. Each roll stack may include a hard roll and a soft roll, and the roll stacks can be arranged such that a hard roll will contact each surface of the web and a soft roll will contact each surface of the web. 
     In accordance with a still further feature of the invention, attachment parts for guiding the web may be coupled to the plate. 
     The present invention is directed to a calender including at least one roll stack having a plurality of rolls arranged to form at least one nip, a stand arrangement including stands located at each axial end of the at least one roll stack, and antifriction bearings arranged to support the plurality of rolls on the stand arrangement. The stands include a plate formed with a bearing edge on which the antifriction bearings are arranged, a contact edge structured and arranged to contact a mounting surface, and a connecting edge forming a connection between the bearing edge and the contact edge. 
     According to a feature of the instant invention, the plate may include a triangular metal sheet arranged as a right-angled triangle such that the bearing edge can be oriented at an angle between about 30° and 60° from a vertical reference. 
     The present invention is directed to a calender including at least two roll stacks, in which each roll stack includes a plurality of rolls arranged to form at least one nip, a stand arrangement for each roll stack, in which each stand arrangement includes a stand located at each axial end of each roll stack, and antifriction bearings arranged to support the plurality of rolls on each the stand arrangement. Each stand includes a plate structured and arranged to form a bearing edge on which the antifriction bearings are arranged, a contact edge structured and arranged to contact a mounting surface, and a connecting edge forming a connection between the bearing edge and the contact edge. 
     In accordance with yet another feature of the present invention, the plate may include a triangular metal sheet arranged as a right-angled triangle such that the bearing edge can be oriented at an angle between about 30° and 60° from a vertical reference. The stand arrangements may be positioned adjacent each other and the connecting edges of each stand arrangement can be substantially vertically oriented, and the connecting edges of opposing stand arrangements may be positioned to face each other. 
     Other exemplary embodiments and advantages of the present invention may be ascertained by reviewing the present disclosure and the accompanying drawing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is further described in the detailed description which follows, in reference to the noted plurality of drawings by way of non-limiting examples of exemplary embodiments of the present invention, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein: 
     FIG. 1 illustrates a calender in accordance with the features of the invention; and 
     FIG. 2 illustrates the bearing edge of the triangular shaped plate. 
    
    
     DETAILED DESCRIPTION OF THE PRESENT INVENTION 
     The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the present invention may be embodied in practice. 
     A calender  1  is arranged at an outlet of a paper machine  2  (shown only in diagrammatic form) to glaze a web  3  coming out of paper machine  2 . 
     To this end, calender  1  includes a first roll stack  4  with a hard roll  5  and a soft roll  6 . The hard roll  5  is made of metal and features a hard, but very smooth surface. Soft roll  6  includes an elastic coating, so that the surface of soft roll  6  is elastic, and hard roll  5  and soft roll  6  are arranged to form a nip to process web  3 . In the exemplary example, the nip is sometimes referred to as a “soft” nip. However, it is noted that the invention is not limited to a formed by a hard and a soft roll, and that the nip can also be formed by two rolls of similar type and/or construction. Rolls  5  and  6  are rotatably supported in antifriction bearings  8  and  9 . Antifriction bearings  8  and  9  are fixed in a stand  10 . It is to be understood that a corresponding stand  10  is positioned at both axial ends of rolls  5  and  6 . Further, various attachment parts, e.g., a deflection roll  11 , doctor blades  12  or a variable speed drive  13 , can be installed on stand  10 . The listing of these various elements is provided for illustration and example and should not in any way be considered as limiting. 
     Stand  10  is essentially formed of a right-angled, equal-sided (isoscolese) triangle, with points  14  and  15  of the triangular shape being capped (truncated) at sharp angles. For ease of discussion, points  14  and  15  are depicted in dotted lines. 
     The hypotenuse of the triangularly shaped element forms a bearing edge  16 , while a lower cathetus (leg) forms a contact edge  17  and the other cathetus (leg) forms a connecting edge  18 . Contact edge  17  is arranged to stands on floor  19  or; if necessary, on an interlayer of a base plate  20 , which is placed on floor  19 . 
     Stand  10  is formed by a metal sheet having a thickness of about 200 mm or more. Accordingly, surfaces of a corresponding width result at the individual edges  16 - 18  of the triangularly shaped element. Thus, stand  10  can stand by itself in a stable manner on contact edge  17  without any further measures. An assembly surface then exists on bearing edge  16 , on which antifriction bearings  8  and  9  can be attached. To this end, it is possible, e.g., to make tapholes (or mounting openings)  22  in the surface on bearing edge  16  (see FIG.  2 ). 
     In the exemplary embodiment, it is shown that the triangle is not only right-angled but also equal-sided (isosceles). However, this is not a requirement of the invention, and is shown as such merely for ease of description and discussion. For example, in lieu of the depicted orientation of the tilt of the roll stack of about 45° to vertical, a tilt in the range of about 30° to 60° is also possible. However, it is advantageous if contact edge  17  is positioned to support bearing edge  16  over its entire length, as shown. Further, it is noted that the relatively high rigidity of stand  10  results from individual edges  16 - 18  being connected by the plate of stand  10 . 
     Also illustrated in the exemplary embodiment, calender  1  includes a second roll stack  4 ′ is arranged on stand  10 ′ and oriented in a mirror-symmetrical manner to stand  10 . For ease of explanation, corresponding parts of each stand are provided with same reference numerals additionally marked with a prime sign (′). 
     Roll stack  4 ′ includes soft roll  6 ′ in the upper position and hard roll  5 ′ in the lower position. In this manner, each side (upper and lower) of web  3  is conducted past one of hard rolls  5  and  5 ′, as well as past one of soft rolls  6  and  6 ′, such that both sides of web  3  are similarly processed in calender  1 , e.g., in the first nip, the hard roll contacts the upper surface and the soft roll contacts the lower surface and, in the second nip, the soft roll contacts the upper surface and the hard roll contacts the lower surface. Accordingly once with its upper side and once with its lower side, while it is next conducted past the soft roll  6  with its under side and then past the soft roll  6 ′ with its upper side. 
     The two connecting edges  18  and  18 ′ stand substantially vertically (or perpendicular) with respect to the floor  19  and/or base plate  20 , and they are arranged adjacent to one another, so that, overall, a relatively small construction space is adequate. An accessible platform  21  is arranged between stands  10  and  10 ′, which can be constructed as a vertically adjustable platform, if necessary. This platform can be used, e.g., for maintenance purposes. 
     Roll stacks  4  and  4 ′ can also include three rolls instead of the two rolls shown in the exemplary illustration. 
     It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to an exemplary embodiment, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.