US2412392A - Parachute - Google Patents

Description

W. S. FINKEN Dec. 10, 1946.

PARACHUTE Fild Feb. 25, 1942 S Sheets-Sheet 1 Dec. 10, 1946. w. s. FINKENI PARACHUTE 5 Sheets-Sheet 5 I Filed Feb. 25. 1942 r INVENTOR. WALTER 6. F/N/l'E/V I i ATTORNEY.

Dec. 10, 1946. w, s, FlNKEN 2,412,392

PARACHUTE Filed Fb. 25, 1942 5 Sheets-Sheet 4 FIG.1 3,

FIG.14.

INVENTOR. MALTE/F a. F/lV/IE/V ATTORNEY.

Dec. 10, 1946. I I w. s FINKEN 21,412,392

PARACHUTE Filed Feb. 25. 1942 5 Sheets- Sheet s INVENTOR. WALTER 6'. FIN/(EN H W rm I ATTORNEY.

l atentecl Dec. 10, 1946 UNITED STATES PATENT OFFICE 2,412,392 PARACHUTE Walter S. Finken, Brooklyn, N. Y., assignor t6 Leonard P. Friedei, New York, N. Y. Application February 25, 1942, Serial No. 432,309

12 Claims. 1

This invention relates generally to parachutes and has particular reference to improvements in the construction of what is usually referred to herein as the canopy of parachutes. The term canopy is used mainly as a matter of convenience in referring to that part of a parachute which acts to support or retard the descent of various loads when discharged or released in the air.

A main object of the invention is to provide a canopy which can be produced at a low cost so that if the parachute is not recovered after use the loss from a cost standpoint will be relatively unimportant; this being effected by a novel construction which incidentally makes the new canopies stronger and more efficient, and the parachutes as a whole more satisfactory in use, than comparable prior parachutes. These features have particular importance when the parachutes are used for such purposes as supporting flares and signals and to retard bombs and similar things when dropped or released. The new canopy is substantially hemispherical in shape when expanded and is composed of sections of woven fabric or sheets of suitable flexible material. Except for heavy duty parachutes a suitable material is a long fiber paper. These sections of material are secured together at their edges by seams. While these seams may be bonded ones, it is preferred to sew them as a matter of manufacturing convenience and because well sewed seams will not open up in packing or in service. However, sewed seams involve making rows of needle punctures and an important feature of the invention resides in the construction of the sections in such a way that they may be joined together with a minimum number of seams in assembling the canopy. The low number of seams is a desirable thing because of the saving in material and weight as compared with prior parachutes, and because it facilitates packing the parachutes in packs or containers of various kinds.

An important incidental advantage is that the paper or corresponding material may be cut with a minimum of waste of the material, the shape of the sections being such that scrap or waste cuttings is reduced to a minimum.

Further, the construction of the sections is such that none of the seams are located along truly radial lines or, in the case of the hemispherical canopy, along lines truly corresponding to lines of longitude on a hemispherical shape. When a parachute opens, particularly when released from an airplane traveling at high speed or when it is discharged by an explosive in any of the usual ways, the opening shock or bursting stress is mainly at right angles to such radial or longitudinal lines and is greatest in a zone around the canopy, the center line of that zone being parallel to the edge or bottom of the canopy and usually located at a distance from the edge equal to about one-third of the total distance from the edge to the center of the canopy. While the seams, because of their construction and location, are not likely to fail under ordinary conditions, seams crossing or located in the zone referred to are protected in a novel Way by shaping the edges of the sec-v tions meeting in that zone to provide excess material at the edges so that when the edges have been sewn together there will be a fullness at each side of each seam which will expand outward under air pressure and thereby relieve the seams from damaging shocks and strains.

Another object is the provision of a novel construction for further protecting the canopy from damage by the opening shock, this being associated with the hem or edge of the canopy. This feature will be hereinafter described in detail, it being sufiicient for present purposes to say that it involves a way of attaching the shroud lines of the parachute which provides a yielding or slipping connection permitting a shock absorbing movement of the shroud lines and the load thereon relative to the canopy when the load is assumed by the canopy, an incidental feature being that the hem is strengthened and reinforced against damage.

With the foregoing objects and advantages in view as well as others which will become apparent later on, the invention consists in a novel construction and relation of parts as hereinafter described, with references to the drawings which accompany and form a part of this specification; the novel features being pointed out in the claims appended hereto.

In the drawings:

Fig. 1 is a diagram illustrating the cutting of sections for subsequent assembling.

Fig. 2 is a diagram showing how the sections of the canopy are related for the final assembly.

Figs. 3 and 4 illustrate steps in the assembly of the sections into the final canopy.

Fig. 5 is a perspective View of a completed canopy. v

Fig. 6 is a section along the line 6-43 of Fi 5 from one edge through the center to the opposite edge of the canopy.

Fig. 7 is a section on the line 1--l of Fig. 5 from one edge to the opposite edge and through the center of the canopy.

Fig. 8 illustrates how the shroud lines are attached to the canopy.

Fig. 9 illustrates the construction of the seams joining the sections of the canopy together.

Fig. 1G is a detail on a larger scale than Figure 8 illustrating the way of attaching the shroud lines to the canopy.

Fig. 11 is a section on the line i| of Fig. 10.

Fig. 12 is a section on the line i 2|2 of Fig. 10.

Figs. 13 and 14 illustrate diagrammatically the construction of a canopy of large diameter for supporting heavy loads. a

Fig. 15 is in part the same as Fig. 10 and illus trates the operation of the shock absorbing connection between the shroud lines and the canopy.

Fig. 16 illustrates a modified way of connecting the shroud lines to the canopy.

The parachute canopies shown in the drawings have, when inflated or expanded under load, substantially a hemispherical shape. The advantages of this shape are set forth at length in Leonard P. Frieder and Walter S. Finken U. S. application Serial No. 422,570, filed December Parachutes for service under conditions where they may not be recovered for re-use, may be made of paper which is strong and light and they may vary in details of construction according to the service for which they are intended.

In the simplest form, the canopy when completed has an appearance resembling half of the cover of a baseball so far as the shapes of the sections and the seams are concerned. This simplest form involves the use of only three pieces of the material as hereinafter explained. The canopy which is illustrated in Figs. 1 to 12, inelusive, employs five sections of the material as shown particularly in Figs. 2 and 4.

In cutting the material, one section is laid out and cut as illustrated at A in Fig. 1. This section is then out along the line 26 to divide it into two parts, 2| and 22. This operation is repeated to provide another pair of parts 2| and 22. Inthe construction shown in Fig. 5, there is another section '23 which is separately cut to provide a seamless center for the canopy. This is animprovement of importance, as, among other advantages, it does away withthe prior merging of seams at the center and lightens the construction without weakening the canopy. In assembling the sections the parts are first put in the relations illustrated in Fig. 2 and the sections are then brought together as illustrated diagrammatically in Figs. 3 and 4 and the parts joined by seams, the ends 'of sections 22 first being joined by seams to the central section 23' and the sections 2| thenbeing joined by seams'to the edges of the section 23 and to the edges of the sections 2|, thereby giving a circumferential shape to the assemblage. The seams between the central section 23 and the sections 2| and 22 are all along curved lines, none of which cross through the center of the canopy.

In the simplest form of construction mentioned above, instead of the three parts 22, 22 and 23 a section is cut as a continuous unit extending from edge to edge'of the canopy, the sections 2|, of course, being cut off from the main or original section A along the line 20. The three pieces are thenjoined together by two long seams.

While no'particular sequence o f'making the 1 sphere.

4 in Fig. 3, leaving only the continuous long seams along the edges of the three parts for joining the parts 2| in position. This long continuous seam is a desirable thing for many reasons, including the advantage it gives in manufacturing the canopies.

As will be seen from Fig. 5, there are no seams in the canopy which lie along truly radial lines or, more properly speaking, along lines corresponding to the lines of longitude on a hemi- However, the long main seams do cross a zone which receives the initial or intermittent shock when the parachute opens under load and seams is of vital importance, it is preferred to g 7 join the sections 22, 22 and 23 first as illustrated this shock may be quite a severe one, particularly Where the parachute is released from a highspeed airplane. This shock zone is illustrated diagrammatically in Fig. 6 of the drawings. The line of maximum stress or the center line of the zone is at a distance from the edge of the canopy equal to approximately one-third of the distance from the edge tothe center of the canopy. The shock stress will, of course, come upon the seams as well as upon the material of the sections and means are provided for relieving or releasing the pressure on the seams within that zone.

Before describing this feature it will be well to explain the construction of the seams joining the sections together. They are all substantially like the one illustrated diagrammatically at 25 in Fig. 9. The seam consists in folds of the material, the plies of material in the fold being secured by a double row of stitches. This gives a strong seam, but nevertheless the sewing involves making two rows of needle punctures which have to be taken into consideration. This is one reason for the seam protecting construction shown in Fig. 6 and referred to above. That protecting construction involves cutting the edges of sections 2| and 22 in such a way as to leave excess material at the points which will fall within the stress zone above mentioned so that when the seams joining sections 2| and 22 are sewed there will be a fullness at each side of the seam and a slackness of the seam within that zone. This is illustrated more or less diagrammatically at 2 in Fig. 6, the greatest amount of fullnessbeing in the Vicinity of the maximum stress line of the zone and running off to a point at either end;

When the canopy assumes its load these fullnesses will be inflated after or as an incident to the opening of the canopies so that the shock of opening is both distributed and absorbedwhich appreciably relieves strain upon the seams. In-

addition, the inflated fuilnesses lie outside of the main configuration of the canopy, therebyaifording what are somewhat'i-n the nature of air pockets which further protect the seams when the canopy is expanded under load. y

The edge of the canopy is folded to give plies of material at the edge of the canopy, one way of folding being as illustrated in Frigpll. The folded material'is then stitched by one or more parallel rows of stitches 27 to hold the foldedJIn'aterial-in place. In making the folds and sewing there is left a space 28 within the hem extending around the canopy to receive a cord 29 which is of about the length of the edge circumference of the can- 01 3. This cord reinforces-the hem to give greater strength and forms apart ofa shock absorbing.

connection between the canopy and the shroud lines of theparachute; 5 a

One form of this shock absorbing feature is ll} lustrated in detail in Figs IO, 11 and 15. It com-- prises a tape 3| which is folded over the edge of the canopy in such a way that the ends diverge .of the section 36.

a d h e iv r in .endsare then secured .by stitches to the material of thefcanopy. These stitches do not include or hold the cord 29 leaving that cord free for endwise movement.

The canopy material and the tape are cut away as shown at 32 in Fig. o as to expose the cord 29. The upper ends of the shroud lines 33 are secured to the cord 29 by any suitable form of knot or fastening. When the canopy takes the shock due to openin and assuming the load on the shroud lines 33 the cord 29 hasa limited endwise movement within the hem of the canopy as the cord is pulled out slightly by-the strain on the shroud lines 33 as shown inFig. '15. The cord, therefore, will have a, slipping, frictional movement relative to the hem and this will be sufficient to provide a yielding connection between the load on the shroud lines and the canopy whichwill relieve the canopy from harmful strain. This movement is of limited extent as the cord is secured to the hem at the points where the canopy seams meet the hem, this being illustrated at 84 in Fig. 15. However, these movements are sufficient to constrict the edge or the canopy to some extent forming what might be termed puckers in the hem and the material which will distribute the strains from the shroud lines along upwardly diverging lines to the material of the canopy.

Instead of using a single tape 31 two tapes may be used as illustrated at 35 in Figs. 10 and 12. This latter construction hassome advantages as the two tapes provide a reinforcement from both sides which will serve to prevent the threads from cutting the canopy material.

In constructing parachutes according to the present invention for use when the service requirements are not severe, the tapes 3| or 35 may be omitted. The shroud lines 33 are each simply passed through a hole pierced through the plies of the hem material above the cord 29 and. then tied or otherwise secured as illustrated generally at 50 in Fig, 16. In this form the folds of the hem are maintained by parallel rows of stitches 5 l The construction illustrated in Figs. 13 and 14 is, as before stated, one which may be used to advantage in constructing large parachutes, the construction shown in those figures being one which has been employed in constructing relatively large parachutes. In this construction there is one long section 36 which extends from edge to edge across the center of the canopy and two sections 3'! and 38 which are in large part the same in shape as the corresponding parts Four sections of the material designated 41, 42, 4.3 and M are all alike, having arcuate edges which cooperate with the edges of the parts 36, 37 and 38 in such a way that when the sections are seamed together the result will be a canopy which is substantially hemispherical when expanded under load, the completed structure being illustrated diagrammatically in Fig. 14 of the drawings. In respects other than the ones just stated, the larger canopies of Figs. 13 and 14 are like the ones previously mentioned.

Parachutes constructed accordin to this invention have been used hundreds of times, many of them under much more severe conditions than are likely to be encountered in normal service.

. They opened almost instantly when freed in the air and with no failures of the canopies. Quick and certain opening is a very desirable characteristic of the new parachutes. In addition, the construction of the canopy is a strong one and economical to make and has all of the other advantages hereinabove specified.

While specific constructions have been described hereinabove in considerable detail, it is apparent that those constructions are illustrative of the invention and it is not the desire to .be limited by anything herein contained, except to the extent indicated by the claims which follow.

What is claimed is:

1. A parachute comprising a load retarding canopy constructed in such manner as to assume a hemispherical shape when expanded by air resistance, a hem around the bottom of the canopy, a continuous cord within the hem free to move endwise within the hem and exposed at spaced apart openings made in the material of the hem, and shroud lines having their upper ends secured solely to said cord at the points where it is exposed at said openings.

2. A parachute comprising a load retarding canopy constructed in such manner as to assume hemispherical shape when expanded by air resistance, a hem around the bottom of the canopy consisting of a plurality of folds of the canopy material secured in folded relation by stitches, a cord within the foldssecured at spaced apart points to the hem and free to move endwise within the hem between said points and exposed at spaced apart openings made through the folds of the hem intermediate the points where the cord is secured in hem folds, and a plurality of shroud lines inserted through said openings and tied at their upper ends around said cord.

3. A parachute comprising a load retarding canopy constructed in such manner as to assume a hemispherical shape when expanded by air resistance, a hem around the canopy consisting of folded material of the canopy held in folded relation by stitches, reinforcing tapes spanning the edge of the hem and secured to the canopy at spaced apart points around said hem, an endless cord within the hem attached to the hem at points removed from the tapes and .free to move endwise relative to the hem and said tapes, the cord being exposed at spaced apart points through openings through the hem and the tapes, and shroud lines secured at their upper ends to the cord at said openings.

4. In a parachute, a substantially hemispherical load retarding canopy composed solely of secrtions of fabric joined directly together at their edges by seams, said sections being so constructed that when joined together a single pressure relieving fullness in the material is provided along both sides of each seam progressively increasing from both directions to a maximum at those parts of said seams which cross an imaginary line around the canopy at a distance from the edge of the canopy of about one-third of the total circumferential distance from the edge of the cancpy and the center of the canopy.

5. Ina parachute, a load retarding canopy composed solely of sections of fabric joined directly together by seams, the edges of said sections being so constructed that when joined together a pressure relieving fullness in the fabric is provided along both sides of each seam, said fullnesses being confined to a zone around the canopy starting about one-third of the distance from the center of the canopy to the edge of the canopy and extending toward the outer edge of the canopy, said fullnesses expanding to relieve the seams from damaging strains within said zone :vhgn the canopy opens to retard descent of its 6. In a parachute, a load retarding canopy composed solely of sections offibrous material having their edges secured directly together-by sewed seams, said sections being so constructed that when the edges are joined together a pressure relieving fullness is provided along both sides of those parts of each seam which lie within a; zone which extends around the canopy and has its longitudinal center line substantially parallel to and at a distance from the edge of the canopy of about one-third of the total distance between the edge and the center of the canopy, said fullnesses each tapering off at the margins of said zone. i

'7. In a parachute, a hemispherical load retarding canopy consisting of a main section extending from edge to edge over the center of the canopy and two side sections each less than one half of the length of the main section, the edges of said main section and said side sections being curved in such manner that they may be joined together by only two seams extending from edge to edge up over the canopy and at a distance from the center of the canopy "sufiicie'n't to leave a's'eamless area around said center.

8. A parachute, comprising 'a substantially hemispherical load-retarding canopy made up of one portion including at least one piece of parasides of the centerwith'the'partsat the edges substantially wider than that part aerossthe cen- V ter of the canopy, aiida pairof similar "side por tions connected to the first named portion"by seams extending continuously from edgeto edge 7 of the canopy-each of said side portions containing' at least one' piece or material and being wholly separate fro'mlthe material of thefirst named portion, and'said side portions being so formed that the seams thereof with the-first named pontioii'ar'e the form of the seams or a baseball cover and are disposed. uniformly inrespect to the center of the top of the canopy and spaced from said center.

9. A parachute canopy in accordance with claim 11. A parachute canopy 'in accordance 'With' claim 8, whereineach ofsaid side portions is cont posed of three pieces of material-seamed together,

and each of said side portions is silnilarftothe other. 1 a

'12. A parachute canopy m'attor'dancetvitn k I 7 claim 8, wherein the first named portion is 'oi ri posed or three separate pieces of-"matria11,m-* J eluding a center piece'and similar side pieces, seamed theretol t WALTER s. mmmit;

Images