FI62966C - SAETT ATT FRAMSTAELLA EN RINGFORMAD CELLKONSTRUKTION - Google Patents

Description

I rRl ADVERTISEMENT, OQ // ^ <11) UTLÄGGNI NGSSKRIFT 6 2 9 6 6 C (45) ΓΛΐ.-ntti. : - ··: v 11 04 1983 ^ ^ (51) Kv.ik.3 / Int.ci.3 B 21 D 47/00, B 21 C 37/12 FINLAND —FINLAND (21) PMenttlhikamus— lh * «n <aMMutln | 3019/72 (22) HakamlspUvi — Aiw5knln | * dt | 31.10.72 (23) Initial Cloud — ClWghattd · * 31.10.72 (41) Interpreters JwlklMkal - WivK offmtllf 06.05.73

Patent and Registration Office (44) Date of NihtivUuiptnon j »ku« L | ulltti * in. -

Patent · och regitterrtyrelten AraOkan utltgd ed »utLskrifun publicarad 31.12.82 (32) (33) (31) ryytaqr μ · οΚμμ- ·· | Μ priori ** 05.11.71 USA (US) 19607 ^ (71) Improved Machinery Inc. , Burke Street, Nashua, New Hampshire, USA (72) Lawrence A. Carlsmith, Amherst, New Hampshire, USA (74) Berggren Oy Ab (5 ^) Method of manufacturing an annular cell structure - Sätt att framställa en ringformad cellkonstruktion

The present invention relates to the manufacture of an annular honeycomb structure, such as the manufacture of honeycomb drums for use in the pulp and paper industry.

As described in U.S. Patent No. 3,320,399, these types of annular cell or lattice structures are usually fabricated according to methods in which the strip material is made helical and welded into axial components that are at least generally unsupported against torsion. However, in the manufacture of structures by means of such known methods, difficulties have been encountered in preventing the tilting of steel strips and the radial distortion of lattice structures caused by the shrinkage of welded joints.

The main object of the present invention is to provide a new and improved method for manufacturing an annular honeycomb or lattice structure, such as a cell drum used in the pulp and paper industry, the method being particularly suitable for preventing the structure from distorting during its manufacture.

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Another object of the invention is to provide a new and improved method as described, which is particularly suitable for the relatively economical and rapid production of such a cell structure.

More particularly, the invention relates to a method of manufacturing an annular honeycomb structure from a separate flat strip and a separate connecting strip, the method comprising the steps of continuously forming an axial structure by winding the flat strip into helical turns on a spindle the turns are connected by a connecting strip to its opposite sides. The essential features of the invention appear from claim 1.

The invention is illustrated below with reference to the accompanying drawing:

Figures 1-4 schematically show one embodiment of the method according to the invention, and Figure 5 is a fragmentary perspective view of a cell structure made according to such a method.

In the drawing, the same reference numerals denote corresponding parts in different figures. The method according to the invention can be used to produce an annular, cylindrical cell or lattice structure 10 from a flat strip 12 and a separate corrugated connecting strip 14. Both strips 12, 14 are made of stainless steel or other flexible metal. As shown in Figure 5, the corrugated or connecting strip 14 may include connecting blocks 18 connecting the entire length of the alternating diagonal blocks 16, with adjacent connecting blocks 18 on opposite sides of the longitudinal median plane 20 of the corrugated strip 14 and the diagonal blocks 16 extending beyond this median plane. However, the corrugated strip 14 may alternatively be corrugated in some other suitable manner to provide openings 22 in the lattice structure 10 with the strips 12 and 14 joined together in a vertical parallel position to form the lattice structure.

According to an embodiment of the invention, a cylindrical mandrel 24 is preferably used, which is preferably made of cast iron or steel and 3 62966 has a circumferential annular outer surface 26 having the same diameter as the inner diameter of the cylindrical lattice structure 10 to be manufactured. The spindle is set on the rotary table, which is rotated by the arrow shown in Figure 1 to indicate the direction of rotation. The strips 12, 14 may first be joined together at their initial or conductive ends and then, when the turntable 28 and its mandrel 24 are rotated, are wound on coils alternately on the outer surface 26 of the mandrel to gradually form an axial honeycomb structure 10 comprising strips 12, 14 along its entire length. alternating coils.

During this rotation of the strips 12, 14, its parallel helices are continuously joined together by successively connecting each block 18 of the corrugated strip 14 with the corresponding adjacent helical part 12a of the planar strip. Such joining is performed at a point (denoted by 30 in Figure 1) where the strips 12, 14 rest on the spindle surface 26 and which, after joining the part 12a, is substantially heated locally. As shown in Figure 1, these joints between the blocks 18 and the portions 12a are preferably formed by welding by means of a conventional welding tool 30a, which in itself provides substantial local heating of the portions 12a during their joining. However, the connections between the parts 12a and the blocks 18 may alternatively be made in another way, such as by riveting, whereby the parts 12a can be heated locally in sequential order by a burner or other suitable means immediately before connecting them to the blocks 18. Exact temperature to which the parts 12a are thus heated , is not critical. However, this temperature should be high enough that subsequent cooling of the portions 12a would cause significant shrinkage in the flat strip 12 in the absence of the mandrel 24.

. The substantially locally heated connected portions 12a are each cooled while the corresponding coil of the flat strip 12 is located on the spindle surface 26 so that the spindle 24 prevents this cooling from causing permanent shrinkage of the flat strip 12 which would otherwise result. Thus, when the coils of the flat strip 12 do not shrink during cooling of the parts 12a, the inherent flexibility of the flat strip 12 allows these coils to stretch beyond the elastic yield strength of the material to counteract shrinkage, and this which would otherwise cause distortion in the cylindrical shape of the lattice structure 10 after removal of the mandrel 24.

In this way, the strips 12, 14 are continuously wound and gradually joined to form an axial lattice structure 10 throughout its desired length, while the heated previously joined portions -12a of the planar strip 12 are cooling on the outer surface 26 of the mandrel. , a lattice structure 10 of the desired length, the rear ends of the strips 12, 14 can be connected to each other, and the spindle 24 and the surrounding lattice structure 10 are removed from the turntable 28. The removed lattice structure 10 and spindle 24 are schematically shown in Figure 2 of the drawing.

If the lattice structure 10 is made of stainless steel and the mandrel 24 is made of steel with a lower coefficient of thermal expansion, this separation can be readily accomplished, as schematically shown in Figure 3, by heating the lattice structure 10 and mandrel 24 in furnace 32 to at least about 370 ° C and at most about 649 ° C. for about five minutes, i.e. until a different thermal expansion detaches the lattice structure 10 from the mandrel 24 to allow it to be removed. The heated lattice structure 10 is then simply removed from the mandrel 24, as schematically shown in Figure 4, so that after cooling it can be used as a filter drum, an air drying drum or for any other suitable purpose. Although this method of separating the lattice structure 10 from the mandrel 24 is particularly advantageous in that it results in the desired reduction in stresses in the lattice structure 10, it may alternatively be detached from the mandrel 24 by any other suitable means. For example, the mandrel 24 may be disassembled when formed as a block structure, or various temperature methods may be used to detach the lattice structure 10 from the mandrel 24. Such methods include rapidly heating the lattice structure 10 above the mandrel 24 and / or cooling the mandrel 24 with a liquid circulating in the mandrel. internally along coolant passageways.

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The dimensional accuracy of the cell or lattice structure produced by the method according to the invention has been found to be considerably higher than it has been possible to achieve with any previous method. Due to the accuracy of this lattice structure 10, considerably less grinding or other machining of the lattice structure 10 is required for final tolerances. In many cases, the accuracy of the lattice structure produced by the method according to the invention is high enough to completely eliminate the need to machine its circumference. The benefit of this reduction or possible elimination of machining helps to produce more economical lattice structures than was previously possible. The method of the present invention also allows, as can be seen, the production of non-distorted lattice structures 10 at a relatively high speed, thus further aiding in the economical production of the lattice structure 10.

Although only one embodiment of the method according to the invention has been schematically described and explained above, the invention is not limited to this single application, but also encompasses other applications within the scope of the following claims.

Claims (9)

A method of manufacturing an annular honeycomb structure (10) from a separate planar strip (12) and a separate connecting strip (14), comprising the steps of continuously forming an axial structure of the cellular structure by winding the planar strip (12) into helical turns on the spindle (24) ) adhering to and between the wound turns of the flat strip (12), and that the wound turns of the flat strip (12) are connected by a connecting strip (14) to opposite sides thereof, characterized in that the connection of the strips (12, 14) is effected ) and the wound turns of the planar strip (12) when locally substantially heated at the interconnections to a temperature large enough for cooling the planar strip (12) from this temperature in the absence of the strip from the mandrel (24) to cause substantial shrinkage of the planar strip (12); 12) locally relevant The heated windings are allowed to cool while in the mandrel (24) to a temperature low enough for the mandrel (24) to prevent permanent shrinkage due to cooling of the planar strip (12) and for the planar strip (12) to stretch as a result. Method according to Claim 1, characterized in that the axially formed cell structure (10) is detached from the mandrel (24). A method according to claim 2, characterized in that the cell structure (10) is detached from the mandrel (24) by heating the cell structure (10) and the mandrel (24) to the extent necessary to cause different thermal expansion and allow the cell structure (10) to be removed from the mandrel (24). the cell structure (10) is removed from the mandrel (24). A method according to claim 2, wherein the mandrel (24) is made of several parts, characterized in that the cell structure (10) is detached from the mandrel (24) by disassembling the latter into its parts. A method according to claim 2, characterized in that the cell structure (10) is detached from the mandrel (24) by providing a temperature difference between the cell structure (10) and the mandrel (24), which causes the cell structure (10) to expand and / or the mandrel (24) shrinkage. Method according to one of Claims 1 to 5, characterized in that the heating of the flat strip (12) is the result of joining. 6 62 9 6 6 Method according to one of Claims 1 to 6, characterized in that the planar strip (12) and the connecting strip (14) are connected to one another at the spindle entry point (30). Method according to one of Claims 1 to 6, characterized in that the interconnection is achieved by welding. Method according to one of Claims 1 to 8, characterized in that the connecting strip consists of a corrugated strip (14) comprising alternating diagonal blocks (16) and connecting strips (18) to be connected to the planar strip (12) on both sides of the central plane of the corrugated strip (14). , and that the joining of the strips (12, 14) takes place by welding the connecting blocks (18) of the corrugated strip (14) to opposite sides of the planar strip (12), whereby these parts are locally substantially heated as a result of welding.