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‘ Dec. 10, 1946. ' 'c. B. LUNDSTROM 2,412,523 METHOD OF PRODUCING WOODEN ARTICLES OF CIRCULAR CROSS SECTION AND VARYING DIAMETER AND THE RESULTING ARTICLE Filed Nov. 28, 1944 7 Fiel FiG.3 3nventor attorneys Patented Dec. 19, 194-6 2,412,523 UNITED STATES PATENT OFFICE 2,412,523 METHOD OF PRODUCING VJOODEN ARTI CLES OF CIRCULAR CROSS SECTION AND VARYING DIAMETER, AND THE RESULT IN G ARTICLE Carl Brynolf Lundstrom, Little Falls, N. Y. Application November 28, 1944, Serial No. 565,542 2 Claims. (Cl. 20-—0.5) 1 2 This invention relates to a method of producing vertically in the corresponding end frames 5 and slender wooden articles and the resulting article. The conventional way of producing slender i5. Thus the two lower ones of the rolls 1 turn on ?xed axes and the third roll ‘I is moved toward and from the other two. Each of these rolls has wooden articles which are circular in cross sec ) tion and which have varying diameters through out their length is to turn them in a lathe. Typ ical examples are the spindles used in chairs and other pieces of furniture. As a consequence, an article so turned is weakest in its small section. The invention produces a similar article which is 10 knurled end portions 8. Any or all of the three rolls may be driven, but it is more convenient to drive one or both of the lower two. The con ?guration of all the rolls is the same. Assume that it is desired to produce a spindle such as that shown in Figure 3 which has a cen nearly indistinguishable from a similar turned tral enlargement A and end portions B of ap article and which nevertheless is quite strong in proximately the same diameter as said central its slender sections, at any rate, very much enlargement and intermediate slenderer portions stronger than a similar turned article would be. ‘C. In such case the rolls would all be formed as The following invention is vintended particu~ 15 is the top roll, clearly visible in Figure 2. larly for the manufacture of furniture compo To produce the densi?ed spindle a cylindrical nents. It may be used in the manufacture of blank whose outline is indicated in dotted lines at any wooden article which is circular in cross sec 13 in Figure 3 is plasticized and then placed be tion and of varying diameter. It affords particu tween the rolls with the top roll in its elevated larly desirable results under conditions requiring 20 position. The plasticizing operation may, if de good mechanical strength. sired, include the step of heating the blank. The It is well known that wood may be plasticized rolls are suitably heated, and while they are be by impregnating it with urea or thio-urea or a ing rotated, the top roll is slowly moved down mixture thereof and may then be densi?ed by ward The e?ect is to densify the wood of the compressing it transversely to the grain in heated 25 blank in varying degrees according to the con dies (see the patents to Loughborough 2,298,017, ?guration oi the three forming rolls. The October 6, 1942, and 2,313,953 March 6, 1943). knurled portions 8 on the rolls will serve to drive With certain woods, water if present in proper the blank from the driven roll or rolls and will quantity will serve as a plasticizer. The present invention produces slender compo nents by plasticizing a suitably dimensioned slender blank and then variably densifying the blank by transverse compression to produce the 30 ensure rotation of any idle roll. Since the invention is concerned with the gen eral principle or method, and the resulting article, no attempt has been made to elaborate the de tails of the roll stand. Axial rolling is a known desired varying cross section. In consequence procedure in other arts and the roll stand itself the slenderest sections are the most densi?ed and 35 is not claimed in the present application. hence the strongest, a novel and valuable at What is claimed is: tribute. If the variations in dimension of the v1. The method of producing a wooden article ?nished spindle exceed what can be attained by of the type described which comprises plasticizing varying the densi?cation, the blank may be a slender Wooden blank in which the grain of the formed to relieve the excess. 40 wood runs longitudinally, and then axially rolling The invention will now be described as used in said blank between heated forming rolls which the formation of a spindle, reference being made are of similarly varying longitudinal contour, to the accompanying drawing, in which— and are caused to approach each other gradually Figure 1 is an end elevation of the roll struc during the rolling operation whereby the blank ture. 45 is densi?ed in varying degrees at di?erent points Figure 2 is a section on the line 2-2 of Fig ure 1. in its length and becomes set as a solid of revolu tion of varying, cross section in which the degree of densi?cation varies in inverse relation to the Figure 3 is a view of the ?nished spindle made in the rolls of Figures 1 and 2, the outline of the cross section. blank from which it was formed being indicated 50 2. A densi?ed wood article of the type de in dotted lines. scribed, in which the article is a slender solid of The spindle is formed by axial rolling and a revolution of varying cross section, the wood typical roll stand is indicated in Figures 1 and 2. grain runs longitudinally, and the densi?cation This stand has two end frames 5 and 6 in which is evidenced by radial condensation of the grain, are journaled two of three identical forming rolls 55 said densi?cation varying in inverse relation to 1. The third of the three rolls 1 is journaled at the cross section. its ends in two frames I l and [2 which are guided CARL' BRYNOLF LUNDSTROM.