US1711824A - Tapered drawn structural element - Google Patents

Description

May 7, 1929. e. E. BARNHART TAPERED DRAWN STRUCTURAL ELEMENT Filed July 12, 1926 yv 7-02 earye f fawn/1 arZ' Patented May 7, 1929.

UNITED STATES enonen arena-near, or resume, amounts. 7

I 'rArEnEn DRAWN STRUCTURAL ELEMENT.

Application filed. July 12,

My present invention relates particularly to tubular'units designed for use in an upstanding or projecting position, as for the support of loads or the resistance or application of pressures; and it is a particular object of my invention to provide for the production, at small cost and by operations which are favorable to the production of so-called fiber therein, of masts, posts, 10 levers, beams and the like, in which the dis tribution of metal and fiber is favorable ,to a maximum strength in proportion to the weight thereof. Posts, beams, and the like, have heretofore been formed 1 from cast, drawn or rolled stock; but the cross sections of units provided for the indicated uses have commonly been uniform throughout the length thereof.

In published calculations and formulas 2o relating to metallic masts, beams, and the like, for the support of particular loads, a uniformity of cross section or a stepped construction has commonly been assumed,v

doubtless for the reason, among others, that the quantity production of drawn tapered elements, in a manner favorable to a desired uniform or non-uniform distribution of.

metal therein, has appeared impracticable;

- but, as set forth in my recent application Serial No. 101,656, filed April 13, 1926, method of drawing elongated metal articles, I have devised practical means for the production of tapered drawn tubular shapes; and it is to the protection of certain especially advantageous shapes, obtainable by the means and methods set forth in my mentioned application, or by equivalent means, that the present application is primarily directed.

Cal

bers, and including the optional provision of drawn base members or units for use in conjunction with masts or posts of the described character, or of any preferred char- It is an object of this invention to providev 1926. Serial m3. 121,781.

acter,such base members or units being optionally tapered but provided with .walls which are thickest inQtheregions. of their least diameter, and including also the provision of cantilever or other beams or mem bers having a non-circularoutline, and/or the provision of stocks suitable for use in the production of tapered levers or other machine parts, may be best appreciated from the following description of alternative embodiments of myinvention taken in connection with the appended claims and the accompanying drawings, in which Fig. 1 may be regarded as a vertical section througha mast or post organization comprising a main tubular unitand a base unit,both units being formedby drawing a tubular stock in such manner as to produce a maximum proportion of fiber in the narrowest regions thereof. Figs. 2, 3 and 4 may be regarded respectively-as cross'sections in the planes indicated-by the lines 22, 3-3 and 44 of Fig. 1, theratio of fiber to cross sectional area therein being diagramatically suggested by the use of Xs.

Fig. 5 illustrates a portion of a post within the scope of my'invention, but disclosing walls which, though tapered, are of uniform thickness.

Fig. 6 may be regarded as a vertical section through a lever, such as a gear shift lever, formed from a tubular unit illustrative of my invention, but bent and provided with terminal members immaterial to my invention.

Fig. 7 is a diagrammatic view of a cantilever beam illustrating an embodiment of my invention in which a tubular element is provided with a non-circular outline and with non-uniform walls.

Fig. 8v may be regarded as a vertical sectfi on, taken as indicated by the line 8-8 of Fig. 9 is a'view showing, on an enlarged scale, an optional cross sectional outline of a part of, for example, the lever illustrated in Fig. 6.

It has heretofore been possible to provide tapered posts of the general form illustrated in Fig. 5 by casting or by the'elaborat'i'on ofsheet metal; but it is possible to provide tubular units of this form by drawing operations such as are described in my 'men- .tioned application; and a great advantage of the drawn products, as compared with cast products or products formed from sheet metal, lies in the longitudinal arrangement and concentration of so-called fiber,- which results from the drawing operation; and, although I may provide drawn units either with uniform walls 11, or with walls which diminish in thickness in the direction of diminishing outside diameter or with walls which increase in thickness in the direction of diminishing diameter, fpr most purposes I prefer to maintain a substantially constant ratio of metallic wall to diameter, substantially as indicated in Figs. 14 inclusive. g

Referring to the details of that specific embodiment of my invention illustrated in Figs. 14 inclusive, the tubular unit 12 is shown as upwardly tapering, except as it is interrupted by an expansion 13 (suitable for the support of a cross arm 14, or the like) and by a constriction l5 (suitable for the support of a split or other ring 16, as for the attachment of an insulator, a guy wire, a pulley, or the like) at a substantially uniform rate.

In order to adapt a post or mast or other unit of the general character described for alternative uses, optionally leavlng a lower or intermediate portion thereof, as the portion 17, in its original state, (the comparatively thick'walls in the region referred to being adapted to resist corrosion, in case the unit is to be inserted in the ground) I may optionally provide the same with additional enlargements or constrictions, as the 'constriction shown at 18, to provide for a split or other ring 19 (adapted to carry a pulley,

or the like, notshown and, if desired, the

unit may be downwar ly tapered, in a manner suitable to its use alternatively in direct contact with the soil, or in conjunction with a base member or unit 20,-the; latter being shown as provided not only with a downwardly expanded portion 21, but with a short upwardly expanded portion 22, adapted to cooperate with a downwardly tapered portion 23 of the said unit 12.

When units 12 are set directly in the ground, whether by tamping within a hole or by driving, or otherwise, a thickest wall portion, such'as the mentioned widest part 17 (presumably representing the original stock) may be disposed at the ground level,any excess metal at this point being utilized in the withstanding of corrosion and/or resistanceto any shearing or other local. force; and the harmonious and/or outward taper of a mast or beam constructed' in the general manner suggested is then entirely suitable to the support of a uniformly distributed load, or to the resistance of unlateral pressures such as those produced by a relative movement of air or waterboth the distribution of metal and the character of the metal, including longitudinal fiber (concentrated in the general manner suggested by the diagrammatic showing of Xs in Figs. 2, 3 and 4) being especially favorable; but, although the unit 12 is shown asprovided with upwardly tapered ends, it is not always desirable that a lower section 23 be provided, or that, when provided, the walls of such a lower section shall diminish in thickness in the manner illustrated in Figs. 2, 3 and 4. For example, the wall 24 of the lower section 23 of a unit 12 may be kept ractically uniform inthickness, even thoug this section be tapered, in order the better to adapt the same to a considerable variety of alternative uses.

Even when a unit 12 (assumed to be comp'leted'by drawing operations executed with requisite variations in rate of relative movement and in pressure, and otherwise as described in my mentioned copending application, or in any other manner suitable to the results herein described) is intended to have its lower section 23 disposed below ground level, I may associate therewith, as indicated, a base unit such as the unit 20,- shown as having its walls thickest in an intermediate region 25, of maximum constriction,a tapered seat 26, above the level 25 being providedby the upper section 22 of the unit 20, a'nd,adapted exactly or ap roximately to interlit with a correspondingly tapered section 23 of the unit 12;

The outwardly flared walls of the lower section 21 of the unit 20 may downwardly diminish in thickness as they expand within the soil or within any mass in which the unit 20 may be embedded; but I may nevertheless qualify the sections 20- for various uses,adapting them, for example, to serve either as bells, embedded in the indicated manner (the downward diminution in the thickness of the walls being then entirely appropriate) or to serve alternatively as exposed base members, suitable to be directlyor indirectly attached to a deck, pavement, or the like,as by means comprising an interfitting plate 27 and a centering or ancho r ing plate 28. The plates 27 and 28 are shown as respectivelyv engaging section 21' of the base unit 20 and section 23 of the mast unit 12, and as being held to a foundation and in adjusted relationship to one another by means of bolts 19, carrying nuts 30.

Forthe purpose of providing access to nuts 30, or for the insertion of any desired filling, or for the disposition of instruments and/or connectionsand/or fittings of any desired character within a bell or base member of the general character described (a cylindrical portion 30*, at,the lower end of the downwardly flared walls 21 bein indicative of the character of the stock rom which the unit 20 is formed, in case the same is produced by my mentioned processyany desired openings may be provided in any of the mentioned units,an opening inthe section 21 being shown as provided with a threaded plug 30, and the unit 12 being provided at 31 and 32 with openings suitable for use in wiring.

As shown in connection with the last-mentioned openings, theowalls 33 through which they are cut may be suitably thickened to obviate aweakening of the same below a proportionate strength characterizing all parts of the unit or characterizing an organization formed by the conjoint use of a plurality of units; and,-if desired, any of my units may be provided with threads (preferably formed byv pressing, or b another operation involving no removal vo metal) a thread at the top of the illustrated post or mastbeing optionally used-for the attachment of a weather-excluding cap 34, and a coarser thread 85, at the opposite (bottom) end being shown as engaging a corresponding thread in a boss 35 upon the centering or anchoring plate 28. It will be obvious that the unit 12 and plate 28 might be used without unit20; and that by suitably adjusting" the plate 28 relatively to the plate 27, and suitably rotating the unit 12, the latter may be brought to a vertical position notwithstanding a slight inclination of the plate 27 ,any necessary wedges or washers (not shown) being interposed between the plates 27 and 28. Y

vIn Fig. 6 I suggest the use of a structural unit 37, whose walls diminish in thickness consistently with the taper thereof, fiber being naturally concentrated in. the

narrow portion 38 thereof, to which a knob 39 may be secured in any preferred way;

and, assuming that the unit 37 is to be used as a gear shift lever of that type in which a bend is provided, the change in direction indicated at 40 may be effected either during a drawing operation or subsequently thereto, in a known manner. a

In the case of a cantilever beam, supported at one end only, such as the beam 41 of Figs.

7 and 8, the desirable rate of increase in diameter and/or in wall thickness being obviously dependent upon the material used and the distribution of the load, I may, for

example, prefer a triangular cross section,- giving to a .web 42 on the upper or tension side thereof a thickness substantially less than that .of downwardly convergent side walls-43, 43' and any planks or other'units of a supported platform, or the like, may be secured in-a suitable way, as by means of counter-sunk screws-44. De ending upon the materials andconditions 0 use,- the inner end of the beam 41, orits equivalent, may be plugged or filled, as at 45', in a manner adapting it to withstand compressive or,

shearing stresses when built into any wall,- as a masonry wall 46, or otherwise secured,

Data regarding the properties of homo geneous beams (including formulas pertinent to moment'of inertia, to sectiona'lmodulus, to radius of gyration, and also bending-moment formulas and'deflection formulas, and comparisons of the properties of cast and drawn structural units respectively assumed to be homogeneous, may be so readily found that I make no effort to include the, same, even for purposes of compari-. son,-an essential fact being that, by reason of-the mentioned concentration of fiber. in

the constricted. portions of my structural units, the published formulas are by no meansjadequately descriptive thereof,--one marked effect of the mentioned concentration of fiber being a notable relative in crease in the toughness or strength thereof relatively to the cross sectional area of constricted portions thereof; but I may mention, in conclusion, that ,the drawing operations referred to are entirely suitable for use not only upon steel tubes, but upon a great variety of other metallic tubes, includ ing aluminum, nickel, brass or alloy tubes;

"and that, although the resultant distribution of metal depends, as set forth in'my mentioned copending application, upon pressures applied and rates of relative movement, the mentioned operations-need involve no application or but little application of artificial heat.

As to the-field of usefulness of my novel units, quoting from a discussion contained in the Elements of Machine Work, copyrighted in 1910 by Robert H. Smith of the Massachusetts Institute of Technology, I

call attention to the fact that structural forks, handle bars, saddle posts, pumps, sulkies, hydraulic and pneumatic tubes,

rings in ring spinning and twisting frames, spindles, rolls, bolsters, shafting, piston rods, piston chucks, bushings, sleeves, diestock handles, pneumatic tools, washers, printing-press rolls, agricultural harvesting and ice machinery, laundry mangle/rolls, mandrels for rubber tires and hose, cream separator bowls, frames of surgical operating tables, dental engines, instrument cases,

bookcases, chairs, tables, fishing1- and um-;

brellja reds, canes, display" frames, magazine 3 30 rifles, air guns, toy pistols, masts, signal and trolley poles and flagstaffs, hand railings,

etc.

They are obtained in three; anneals,- hard, stiff (cannot be bent) medium, tough I (can be bent slightly) soft, ductile and Phable (suitable for bending or forming into special shapes).

Small'machine parts can be readily made by using tubing slightly over-size, then.

grinding or machining to size. The parts .may or. may not be case-hardened. Joints are made by brazing, threading, fianging, expanding, heading, and by shrink, force, drive, sliding, or push fits.

- Sign posts, mail box sup orts and lamp supports (as well as automo ile body members and many additional items) might naturally have been included within the plane longrons,

above somewhat random enumeration, in viewof the fact that uniform seamless drawn tubes up to twenty inches in diameter are said to have been on the market for many years; but the omission of mention of aerowing frame members and/0r struts, and also the omission of mention of especially rugged and weight-economizing masts required by submarines (these 'being among the uses to which my structural units are very advantageously applicable) may doubtless be attributed to the 3 recentness of the notable advances made in aerial and submarine navigation.

Although I have herein described several alternative embodiments of my invention, it

should be understood not. .only that various features thereof might be independently employed, but also that numerous modifications additional to those suggested, might easily be devised by those skilled in the art to which this case relates, without involving the slightest departure from the spirit and scope of my invention, as the same is indi cate'd above and in the following claims.

The term drawing is herein usedto include not only operations of the type heretofore commonly so called but also such combinations of rolling and drawing-as are described in my mentioned application, these combination operations being applicable as well to highcarbon steels. that some of my results are obtainable even by rolling, without drawing; but one of the important results of my preferred mode of production which includes drawing is the mentioned increase in longitudinal fiber,-- this effect being so notable as to improve the resistance of some of my structural elements to transverse bending strains by or more (tensile strength and compressive strength being also increased, parallel to the grain) as compared with elements of identical weight produced (in case they can be so I have found' and in which the thickness of wall increases f in' the direction of diminishing diameter.

2. In means of the general character described: a seamless drawn and tapered tubular structural unit which varies in diameter and whose walls are thickest in a region where the outside diameter is least.

3. In means of the general character de scribed: a seamless drawn and tapered tubular structural unit WlllCh varles in diameter, .and whose walls are thickest in a region where the outside diameter is least, said unit expanding inopposite directions from said region.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 1st dayof July, 1926.

GEORGE E. BARNHART.

V CERTIFICATE or CORRECTION.

Patent No... "1,711,824.

cricket's; BARNHAR'I..

la .iu ihcrcby certified that error appears in, the'pr'inted sfpccificationrof.the

an nimibered patent requiring correction as follows: lafeili l-ine 30, for

'No! 101,656" road "No; 101,6511'; and that mend Lctters'Patent should be read with this. correction therci'n that. the "sa ine may conform to the record of the cu'e'in" the Patent Office.

Signed and sealed mama (layof- ;Joly, n." pli 1929.

(see f- M. J. Moore, I I Actingfiommissioner of'Patente.

CERTIFICATE OF CORRECTIQN.

Patent No. 1,711,824. Granted May 7, 1929, to

GEORGE E. BARNHART.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, line 30, for "No. 101,656" read "No. 101,651"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 2nd day of July, A. D. 1929.

M. J. Moore, (Seal) Acting Commissioner of Patents.

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