US1710350A - Constructional element - Google Patents

Description

April 23,1929- 7 E.- J. DEWOITINE 1,710,350

CONSTRUCTIONAL ELEMENT Filed March '7, 1925 2 Sheets-Sheet i 2M -m Dwm April23, 1929. E. J. DEWO ITINE I CONSTRUCTIONAL ELEMENT Filed 'uarn v, 1925 2 Sheets- Sheet Patented A r. as, 1929.

' nane EMILE JULIEN DEvVfillIll'E, OE QHATILLQH, FRANCE.

I COEiiTRUCTEONAL lELl F'llifEi l il T.

lippli'uzation. filed March 7,1925, Serial No. 1 5,749, and in Belgium April 18, 19:24.

relates to a simple and imsoars or lone'rons mients oit aeroa designated they are formed are utilized to greater ad vantage than has hitherto been vthe'c'ase.

The constructional elements. or beams are oithe kind in whiehthe resisting moment is caused to vary in a continuous manner by soproportioninp; height oi"? the beam' that at any sectionthe total moment of resistan'ceis as near as possible to the moment of fiexion due to the load. I r l The esssential feature of the invention consists intermingthe beams with plates -which are thinned away or diminished, in

. the direction of their'thiclrnessl The invention includes various constructional embodiments or arrangements which will be more fully described hereafter, and as. new industrial products special parts suitable for their manufaetureas well as devices, especially aeroplanes provided with beams or spars of theclass in'question;

In order that the invention may lJG'lllOl'G clearly understood, it will now be described with r ference to the accompanying drawings, but it is to be observed that the de scription and drawings are way of example.

Figs. 1, 2, 3, .4- and 5,'inclnded in the drawings are all partperspective views of beams or spars adapted to be fitted inposigiven merely by tion and to worlr under flexion, and constructed according to as many method-sot carrying'out the invention.

In formi g work under flex-ion, and especially suitable for use as a spar in the Wing of an aeroplane, or a longron, the procedure 18 substantially as follows.

It is known. that at each right section of a beam under transverse stress, the material utilized must resist in particular a shearing strain, a torsional strain'and especially a force of fiexion, the predominant compo-.

nents of which correspond to the. flexion in the direction ofthe length, as for example 1n the case oi the longron orfspar'o'f. the

pendsfupon the section oi 1' ninimum. we rht; ally s;

ficient.

the beam or spar' intended. to

For this purpose the ment or beam may with advantage comprise,

wing of an aeroplanm the liexion due to thewidth oithe wing. v V

The resistance to the she; term he serial-devoted to the work. This condition-is usu- L istied by the dimensions imposed by the other-forces, at any "ate to a certain t e i n the junction of the beam.

es upon tne polar momen ofinertia of .L L are section, which is also generally sut- It is 1n the predominant directionwhich'must 'n ive the principal factors in the. structure jot inertia. lirom what has just been state 1, be seen that thebeam. must be constructed in such a way tiat whilst the material is judiciously' utilized both as regards price Y and weight, the res stingnioment of the whole shall vary in a continuous manner from the port of attachment to the other extrei'nity', ant so that the strain on thewmaterial shall to the for e ottorsion do the resistance to the force of fle'Xion it will I in all cases be as near as possible to thead- LiSSllOlG limit, V i 7 It is also known that with equality of the modulus of section or the same rectangular frame, it is desirable to distribute the mass as. far as possible from the neutral line, but inorder to avoid buckling of a plate it is important that the'breadth shall have t the thickness ished by the addition of? one or a plurality of plates or extra thickness' an appropriate minimum ratio; In nractlce the tendency tobuekle is dimin- In what follows a simple construction. is

described permittingg'platesor the like to be utilized the thickness of WlllCll can be lessened at will and having a variable moment of inertia.

constructional eleand as shown atl igs. 1 and 2 which illustrate ainethod of manufacture especially suitable for relatively small spars'a: soliddrawn plate at having in the neighbourhood this case also comprise ribs Z) for the purposes already described. The structures may be formed from plates 0 in e si l piece as indicated at Fig. 3 when 'ltcllltl'crj for making such plates are available, but preferably the practical COllSti'llQilOil is that indicated atlligs. l and 5 where each constructional. element comprises two parts (Z and a, one superposed above the othu and attached to gether by means of rivets f. When. actually titted together longitudinal spaces are "formed bounded laterally by a certain num- 301' of inner ribs These different l"' .ds ot elem nts are uniform in width and are reduced in tra'isveri-io thickness by sawing; or pla ng as e case may be so that their sections diminish regularly in the desired me iiier from the point of attachment to the tree extremity oi the beam as shown at Figs. 1 and 3. This reduction in thickness is elleeteo on the opposite to that carrying the. reinforcing webs or ribs and also necessary at the extremities ot the said rib. Hence the Wing fiercurc members may have substantially the same width throughout, but their transverse thicknes decreases, so that the portion of the member directl' adjacent the point of attachment to the frame of the aeroplane has the greatest moment of inertia. As show u in the drawings, the WlCltllO'f a memher is greater than its thickness. As previously stated, the diminis iing thickness of the tlexure member may besecured by shaping the main portion thereof, or the ribs, or both.

In some cases the element may comprise, whatever may be the arrangement adopted and shown atFigs. 2 and 5, between the ribs 5, a certain number of extra ribs h In the foregoing manner 0.. constructional element is obtained adapted to be applied Whenever a beam or spar is required intended to work either under flexion as in the case for instance with the spar of thewingr ot an aeroplane projecting outwards; or. under l'lexion and compression as in the case wing with several. suppm'ts and the constructional element is found tulliii ments as already stated.

it is to be understood tl not limited to "c part eimir application or the constructl embodimei which have been moi-s particularly described, but thet 1 modifications are included lia ling witl the claims.

*7 the inve. tion a interpretation w l fhatl claim and desire to secure by ters latent of the United Stwtes of linerica l. A structural element for aeroplane wi gs comprising a hollow rigid member de creasing in transverse tl-iicliness irom the point of attachment thereof to the freeend thereof, the he" of .said' rigid .-.ow port r member ravine; rem'rorcmg web means of l rig-1d member hav a plurality of loi dinsl external l'GiZ orcinp; ribs.

wing tleXure said element decreasing in thickness from one extremity to the other, said member hav ing reent'orcing ribs ass elated therewith and extending externally thereof in the direction of its thickness. r 7' In testimony whereotl have hereunto set my hand.

EMILE JULIEN DltWOlllllll.

requiremember for aeroplanes do two body portions having conlongitudinal ribs adapted to'hold"

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