US2378759A - Manufacture of airplane frames, etc. - Google Patents

Description

Jqne 19, 1945. A. FENER 2,378,759

MANUFACTURE OF AIRPLANE FRAMES, ETC

Filed Marsh 2., 1943 INVENTOR ATTORNEY Patented Julie 19, 1945 2,378,759 MANUFACTURE og i mrmnn FRAMES,

UNITED STATES PATENT OFFICE.

Abe Fener, Bronx, N. Y., assignor to Clara Fener, New York, N. Y.

Application March 2, 1943, Serial No. 477,701

3 Claims. (Cl. 153-32) This invention relates to the fabrication of airplane structural parts. More particularly my invention is directed to an improved process for shaping and fitting a finished frame unitin accordance with a template or jig.

The process for fabricating airplane frame units generally includes heat-treating such units by dipping them into a chemical bath for toughening purposes, or by treating them in other suitable well known ways, with the result that these frame units become distorted from their normal desired shape and cannot be properly assembled. It is therefore necessary to restore these distorted frame units to their desired shape in accordance with a template or jig. The method heretofore employed for shaping th distorted frame units consisted in hammering' the unit to thereby force it into shape. 'lhisformer method contained many inherent disadvantages among which were the following: Since these airplane frame units generally comprised flanges along the longitudinal edges thereof and cut out or notched edge portions which are known as stringer rests designed to accommodate the stringers used in the assembly of the frames into the airplane, in a large proportion of the cases processed by the old method the frame units would split or crack in the area of these stringer rests mer since it was the weakest parts of the frame unit structure. As a result the cracked frame unit had to be scrapped. This represented a great loss of time and material and retarded the speed of production so vitally necessary in war times. The applicant is aware of one plant, in which the above described hammering method of restoring the frame units was employed, where out of twenty frame units completed by one man in one day, as much as fifteen frame units were rejected by the inspector and junked as cracked .or broken.

Another-disadvantage of the frame fitting or shape restoring process as heretofore practiced was that due to the fact that by repeated hammer blows on the material, certain areas thereof became thinner than others, thereby greatly weakening the frame and rendering it unsafe for use.

It is therefore one of the principal objects of my invention to provide a highly improved, yet simple, process for restoring or otherwise shaping airplane frame units so as to eliminate the above described disadvantages and which shall at the same time be attended with additional advantages as will hereinafter become apparent.

when struck with a hamduring such treatment the frame units become unit the said frame This application is a continuation-in-part of my copending application Serial No. 444,154, filed May 22, 1942, for Manufacture of airplane frames, etc. Y

In the accompanying drawing in which is shown an embodiment of my invention:

Fig. ,1 is a side elevational view of one type of airplane frame unit upon which the: process of my invention is practiced;

Fig. 2 is an edge elevational view thereof;

a Fig. 3 is a side elevational view of the frame shown in Fig. 1, but illustrating the same supported in accordance with my invention;

Fig. 4 is a top plan view thereof;

Fig. 5 is a view similar to Fig. 3, but illustrating a further step in my improved process;

Fig. 6 is an enlarged cross-sectional view taken substantially along the line 6-6 of Fig. 5; and

Fig. 7 is an enlarged cross-sectional view taken substantially along the line 1-1 of Fig. 5.

Referring now in detail to the drawing I have shown therein for the purposes of illustration 8. frame unit I!) of the type employed in the fabrication of airplane frames, but which may be of any customary shape or design. The frame unit, is generally proyided with continuous nanges ll along the longitudinal edges thereof with the exception of certain'areas, such as for example at l2 to 20 where there is an interruption in the continuity of a portion of the flanges II. It is also noted that adjacent these said areas I2 to 20, the frame unit is notched inwardly from the edge thereof to provide rests for the stringers ultimately used in the assembly of the frames. These stringer rests may be of any shape consistent with the design of the airplane.

As explained above, these frame units II) are heat treated or otherwise treated for toughening the frames or for any other desired reasons, and

misshapen or distorted.

In accordance with the following process for restoring or otherwise shaping the distorted frame units without spoiling or otherwise rendering the frame unit unfit or unsafe for use.

I first position a pair of blocks 26 and 21 on opposite sides of the frame unit In and between the flanges II, which may be disposed as to overlie the stringer rest l2, and rigidly secure unit and blocks in a suitable such as, for example, between vise 20. The frame unit I0 is holding means, the laws of a my invention, I provide outwardly.

made of wood, but

preferably supported in thevise 20 at a point approximately near the center thereof with opposite ends of the said unit I!) freely projecting I then position a second pair of members '32 and 33 on opposite sides of the frame unit I, adjacent the flange and in the vicinity of and overlying opposite sides of another one of the notched areas, such as for example the area l3. These blocks 32 and 33 are maintained in position by suitable clamping means such as, for example, the clamp 35, as shown in Fig. 6 of the draw.

relatively rigid block ing. I then position a third pair of blocks 31, 38

on opposite sides of the frame [and overlying the stringer rest 14. A clamp 35 holds these blocks 31 and 38 in position. I now correct or restore that portion of the frame unit l in the area where the pairs of blocks 26, 21, 32, 33 and 31, 38 ar positioned, by bending, pulling, pushing or twisting the frame, manually if desired, to conform to a desired template or jig. The said clamped pairs of blocks prevent cracking or breaking of the frame unit at its vulnerable points adjacent the said notched areas l2, l3 and M by preventing too sudden or sharp a bend and by distributing the bending, pushing or twisting forces applied. It is particularly noted that this restoring process has been accomplished without resorting to violent hammer blows. I have found that good results are obtained when the said block members are longer than the notches which they overlie.

In accordance with my invention, I have found that when three sets of block members are clamped in position covering three adjacently disposed notches or stringerrests, I obtain excellent results when working in the general area of the said three stringer rests. But it is understood, however, that any other desired number of pairsof .blocks may be employed and disposed in any other desired arrangement.

I have found that I obtain good results when the block members 26, 21; 32, 33 and 31, 38 are it is understood that they may be made of any other known material suitable for the purposes set forth. p

In accordance with the provisions of the patent Y and practice of my outlined, and the invention extends to described the principle invention, together with the best apparatus or steps which I now consider to represent the best embodiments thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can .be practiced by other apparatus, also, while it is designed to use the various features and steps in the combination and relation described, some of these may be altered'and others omitted without interfering with the more general results statutes, I have herein Having described my invention, what I claim and desire to secure by Letters Patent is:

1. In the process frames for fuselage or wing construction wherein a finished frame unit, having certain areas thereof weakened by notched spaced stringer rest portions, is treated for toughening Or for other purposes and in which the said treatment causes distortion of the said frame unit from its desired shape-that improvement for restoring the said distorted frame unit to its desired shape which comprises the steps of positioning a pair of blocks on opposite sides of said frame unit and clamping the said blocks and frame unit in a vise member to support the same with opposite ends thereof projecting freely beyond raid vise, positioning one or more pairs of rigid members on opposite sides of said frame unit and substantially bridging said notched stringer rest portions, supporting said rigid members solely by said freely projecting portions by clamping said pairs of rigid members in position and then exerting a pushing, pulling or twisting force on said frame, in the area of said two adjacent stringer rest portions to restore its shape in accordance with a template or jig.

2. A process for manufacturing airplane frames or the like according to claim 1 in which the said rigid members preferably have a degree of rigidity on the nature of wooden blocks.

3. The process of manufacturing airplane claim 1- in which twisting force is ABE FENER.

such use.

of manufacturing airplane

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