US 2401542 A
Description (OCR text may contain errors)
June 4, 1946. c. BOOTH PROCESS FOR MAKING TUBING Filed April 3, 1.944
- INVEN'EFOR. 59m. Cifloonr,
Patented June 4; 1946 UNITED. 1 STATES PATENTTOFFICE PRocEss FOR-"MAKING TUBING Earl C. Booth, Columbus, Ind; assignor to Noblitt-Spark's Industries, Inc., -I nd., a corporation of Indiana Columbus,
, Application April 3, 1944, Serial No. 529,348
This invention relates to tubularmetallicarti cles and more particularly to a process for producing them. My object is toreduce the cost of manufacture of such articles and to increase about its axisthat the load will be applied in the plane of the web; and if, the tubingis bent in forming the finished article, the bendingis preferably done in the plane of the web.
The accompanying drawing illustrates my invention. Fig. 1 is a side elevation ofa chair embodying tubular supporting elements formed in accordance withmy invention; Fig. 2 is a transverse section on the line 22 of Fig, 1; Fig.3 is a transverse section of an extruded strip suitable for use in forming the tube shown in Fig, 2; ,Fig.
" 4 is a transverse section through a modifiedform of tube; Figs. 5 and 6 are .transversesections of alternative strips suitable for use in forming the tube of Fig.4; Fig. 7 is a section similar to Fig, 2 illustrating a further modification; Figs, 8 and 9 are transverse sections illustrating alternative strips suitable for use in forming the tube of Fig. 7; and Fig. 10 is a transverse section similar to Fig. 2 showing a tube formed of flat strip stock.
The chair illustrated in Fig. 1 is shown merely to illustrate one use for m invention and embodies supporting members [5 formed of metal tubing and located at opposite sides of the chair. The tubing of which the member I5 is formed is circular in section and embodies interiorly a diametrically extending web.
The tube shown in Fig. 2 is conveniently formed from a metal strip having the cross-sectional shape illustrated in Fig. 3. Such strip has a central portion l6, which may be approximately plane, side or intermediate portions l1; and edge portions l8. The portions H are desirably curved on a radius equal to the radius of curvature of. the cylindrical wall in the finished tube. The edge portions l8 are plane. Desirably, the interior of the junction between each curved portion I! and the adjacent plane portion 18 is 4 Claims. (Cl. 29-156) a r 2 r formed. with arather generous fillet 20, while exteriorly such junction is characterized by a well-defined edge 'Zl representing the intersection of the mutually perpendicular outer surfaces of the portions I .1 and I8. The strip of Fig. 3 is desirab ly formed of aluminum, aluminum alloy, or similarmetal by extrusion.
In forming a tube from astrip of the crosssectionillustrated in Fig. 3, the center portion of th strip is curved transversely, to bring theedges 2I -2l together with the opposedfaces of the edge'portions l8 in contact with each other to form a diametrically extending web, as shown in Fig. 2. To complete the tubing, the edge 2l-2| are welded together, and thefree edge of the Web formed by the portions l8l8 is welded to the center portion It at the point indicated at 22 in Fig. 2. 1 Such welding need not be continuous,, and is desirably carried out by the condenser-type process.
In the tubin illustrated in .Fig. 4, the center web 25. is, of single thickness. be formed of an extruded strip having a generall T-shaped cross-section similar to those illustrated in Figs. 5 and 6.. In Fig. 5, the center web 25 is united along one edge with two oppositely projecting. flanges. Adjacent the web '25, the flanges are curved in cross-section as indicated at 26, desirably to thecurvature of the cylindrical wall of the. tubing in Fig. 4; while beyond such curved portions the flanges are approximately plane, as indicated at 21. The junction of the web 25 with each curved flange-portion 26 is characterized by an interior fillet 28.
In forming a tube of the strip shown in Fig. 5, the relatively plane flange-portions 21 ar curved to abut each other over the free edge of the web 25, as will be clear from Fig. 4; and the abutting flange-edges are then welded together and to the adjacent edge of the web 25.
The strip illustrated in Fig. 6 is similar to that shown in Fig. 5 except that the flanges have their relatively plane portions 30 located near their junctions with the flange 25 and their outer edges curved as indicated at 3|. In forming a tube of the strip of Fig. 6, the flange-portions 30 are curved to bring the free edges of the portions 3| together above the free edge of the web 25, and all such edges are then welded together.
The tube illustrated in Fig. 7 resembles that shown in Fig. 4 except that the flanges forming the cylindrical tubewal1 are united respectively with opposite edges of the center web 25. Such a tubing may be formed of a strip having the general Z-shaped cross-section illustrated in Fig. 8;
This tubing may I In that strip, the two flanges are joined respec- 4 ing embodies but one joint or seam visible'irom' the exterior, as is the case in the tubes of Figs. 3 and 10, the joint is desirably disposed on the inside of the bend where it will be least conspicuous.
I claim as my invention: 1. A process of forming metal tubing having a. transversely extending, interior web, which comprises extruding metal to produce an integral to the strip shown in Fig. 8 except thatthe plane v portions 38 of the flanges are located adjacent the web while the edge portions are curved as indicated at 39.
The extrusion process, v I in producing the strip of which my tubing is formed, has the advantage that it produces a strip admirably suited to the production of tu'b-' ing of attractive appearance. Desirably, a large.
part of the transverse extent of the strip-portions which are to constitute thecylindrical tube-wall are formedin the extrusion process to have a curvature corresponding to the curvature of that wall. This ,reduces the amount of transverse bending whic'h niust be performed in convertin the stripinto a tube. Further, strip-portions whose form"cannot be readily changed in the operation of converting the strip into a. tube may be forrned' byfthe extrusion process to have a curvature corresponding to that of the outer surface of the finishedtube. Examples'of such'stripportions are those'adjacent the edges 2| in Fig. 2 and those adjacentthe bases of the webs and indicated at 32 inFigs. 6, 8,-and 9. Again, the extrusion process permits the formation of relatively sharp edges on portions which are to be joined to others in the'finished tube and thus aids in making the'jointrelatively inconspicuous. 'The tube shown-*in Fig. 10' is made of flat strip-stock having a center portion .4! transversely curvedto form the'cylindrical tube wall and edge portions "bent in'war'dlyand lying in juxtaposed'relation to fori'n the reinforcing web. The edges of the central portion are secured toat the'point 44. I
In formingthe chair-supporting element I? from any of the tubes described; the tube is converted into the desired shape by bending it in the plane ot the interior web. In such bending, the web is prevented from buckling by reason of thefact that both its longitudinal edges are s'e-- cured to the tube-wall, and the web adds greatly to the strength of the element. Where the tub- 'which I prefer to use elongated strip having wall-forming and webforming portions, parts of each wall-forming portion and the junction of the-.:.web-forming and wall-forming portions being shaped in the ex-- trusion to the cross-sectional form they are to .possess in the finished tubing, curving the other partorparts of each wall-forming portion to form a closed tube across the interior of which theweb-forming portion extends diametrically with its edge in contact with a, wall-forming portion, and then welding such web-edge and wallforming portion together.
2. A process of forming metal tubing having a transversely extending, interior web, which comprises extruding metal to produce an integral elongated strip having a central, Plane, 'webforming portion and symmetrical wall-forming portions extending in opposite directions from one edge of said,'web-forming portions, a, part of each wall-forming portionjand the junction of the web-forming 'and wall-forming portions bemgsna ed inthe extrusion to the cross-sectional shape they areto'have in the finished tubing,
I curving the other part of each wall-forming portion to form a closed tube with the free edges of the wall-forming portions meeting at the free edge of the web-forming portion, and then welding such free edges together.
3. A process of forming metal tubing having a gether by welding at the point 43,"and theffree edge of'the webis welded to'the cylindrical wall prises'extruding metal to produce an integral elongated, strip having a central, plane, webformi'ng portion and symmetrical wall-forming portions extending in opposite directions from one edge of said web-forming portions, the junction of the web-forming and wall-forming portions being shaped in the extrusion to the crosssectional shape they are to have in the finished tubing, curving each wall-forming portion to form a'closedtube with the free edges of the wall forming-portions meeting at the free edge of the web-forming portion, and then welding such free edges together.
'4. The process set forth in claim 1' with the further step of bending the tubing. in the plane EARL C. BOOTH.