US3032072A - Parachute fabric containing stretchand non-stretch-type ripstops - Google Patents

Description

May 1, 1962 1.. 1. WEINER ET AL 3,032,072

PARACHUTE FABRIC CONTAINING STRETCH AND NON-STRETCH TYPE RIPSTOPS Filed April 26, 1960 Fig). 5.

INVENTORJ LOUIS Wainw- Harold H Brandt ATTORNEY United States Patent Ofifice Fatented May 1, 1962 3,032,072 PARACHUTE FABRIC CQNTAINING STRETCH- AND NGN-SIRETCH-TYPE RIPSTUES.

Louis I. Weiuer, West Newton, and" Harold. H. Erandt,

Natick, Mass assignorsrtothe United States of America as represented by the Secretary of the Army Filed Apr-.26, 1960, Ser. No. 24,857 6 Claims. (Cl. 13422) (Granted under Title 35, U.S. Code (1952), see. 266) The invention described herein, if patented, may be manufactured and used by or for the Government for governmental purposes, without the payment to us of any royalty thereon.

The invention relates to parachutes and has for one of its objects to provide a parachute in which the initial shock at the time of opening is very materially reduced.

More specifically, it is an object of the invention to provide a parachute fabric having incorporated therein a plurality of symmetrically arranged ripstops of elastic material which not only limit the extent of a possible rip in the fabric but also provide for an instantaneous stretch of the fabric upon first opening of the parachute so as to permit the passage of an extra amount of air through its interstices to modify the extent of the initial shock to the person or cargo associated with the parachute.

Other'objects and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawings, in which,

FIGURE 1 is a plan view of a rectangular section of the parachute material on a greatly enlarged scale.

FIGURE 2 is a greatly enlarged sectional view taken on the line 2-2 of FIGURE 1, and

FIGURES 3 and 4 are plan views on a smaller scale of Sections of modified constructions of parachute material in which the ripstops are arranged somewhat differently from those of FIGURE 1.

Referring to the drawings in greater detail and by reference characters, the three slightly different multifilament nylon fabrics shown in FIGURES 1 to 4, inclusive, are indicated by the letters A, B and C, respectively, and each of them is so designed as to not only prevent excessive ripping of the fabric while in use, but also to increase its air permeability over that of present standard fabrics when the pressure differential across the fabric is high Without increasing it when the pressure differential is low. In other words, each of these fabrics provides for high air permeability only momentarily, i.e., when it is first subjected to the shock created when the parachute opens. Thereafter the fabric returns to its normal degree of air permeability, which is that of the present standard parachute fabric. This novel functioning of the parachute fabric is accomplished by reason of the elastic or stretch type threads which are used to replace certain of the conventional rip-stop threads as will now be described.

In fabric A, which may be of Dacron, nylon, or the like, each pair of double rip-stop filling threads is indicated by the numeral 1-1, while the pairs of double ripstop warp threads are indicated by the numeral 2-2. In this form of the invention, the rip-stop threads 1 are of the stretch type, while the warp rip-stop threads 2 are of the non-stretch type. Threads 3 are intersticial threads between the rip-stop threads.

In the modified form of the invention shown in FIG- URE 3, only the rip-stop threads themselves are shown, and the fabric B of this illustration is provided with pairs of elastic double rip-stop filling threads 1-1. In this illustration, each third rip-stop filling thread is shown as of the elastic type, but it will be understood this number may be varied in accordance with the degree of temporarily increased air permeability that is desired. The conventional rip-stop threads, both' warp and filling, are indicated by the numeral 22.

In the modifiedform of theinvention shown in FIG- URE 4, the fabric C is substantially the same as that shown in FIGURE 3 except that in addition to the elastic ripstop filling threads 1-1, every tenth warp rip-stop consists of the double elastic threads 1-1, and the spacing of these elastic threads may be varied 'in accordance with'the desired increase or decreasein air permeability.

The elastic stretch-type threads employed for the pairs of double rip-stops may be of the general type shown in Billion Patent No. 2,564,245 in which synthetic yarns or threads are processed so as to be permanently twisted and crimped and thereby provide a stretch-type thread.

In the operation of these novel fabrics when employed as canopies in parachutes, the stretch-type threads will elongate more than the multifilament threads (particularly where it cosses the rip-stops which are at an angle of as the pressure differential across the fabric increases, and return to its original length as the pressure differential across the fabric decreases. The increased size of the openings resulting from this temporary elongation will result in increasing the air permeability when desired, i.e., at the higher pressure differentials. Experimentation has shown that incorporation of a stretch-type thread in every third filling rip-stop (fabric B) resulted in an increase of approximately 9 percent in the air permeability of the fabric over that of a similar fabric without the stretchtype threads when a determined at 20 inches of water. Thus, whether the threads forming every filling rip-stop, or every second, third, fourth, etc., filling rip-stop should be of a stretch-type will depend upon the increase in air permeability desired and upon the degree of stretch in the thread.

It is apparent from the foregoing description and the attached drawings that we have devised and exceedingly simple construction of Woven fabrics which incorporates within itself the means for substantially reducing the initial shock to the cargo or person using the parachute while automatically permitting the material to return to its normal condition within a matter of seconds so that it may otherwise perform its retarding functions in the identical manner as parachutes in which the canopies are formed of conventional parachute material.

In accordance with the patent statutes, we have described what we consider to be the preferred forms of the invention, but inasmuch as various minor changes may be made in structural details without departing from the spirit of the invention, it is intended that all such changes be included within the scope of the appended claims.

We claim:

1. A woven parachute fabric having both stretch type and non-stretch type rip-stop threads incorporated therein, and intersticial threads between said rip-stop threads, at least some of the rip-stop threads in one direction being of the stretch type, and at least some of the rip-stop threads in the other direction being of the non-stretch type; whereby the air permeability of said parachute fabric is temporarily increased upon the opening of a parachute made therefrom, so as to reduce the initial shock to the parachute load.

2. A woven parachute fabric having both stretch type and non-stretch type rip-stop threads incorporated therein, and intersticial threads between said rip-stop threads, all of the rip-stop threads in the filling being of the stretch type, and all of the rip-stop threads in the warp being of the non-stretch type; whereby the air permeability of said parachute fabric is temporarily increased upon the opening of a parachute made therefrom, so as to reduce the initial shock to the parachute load.

3. A woven parachute fabric having both stretch type and non-stretch type rip-stop threads incorporated therein, and intersticial threads between said rip-stop threads, some of the rip-stop threads in the filling being of the stretch type, the remainder of the rip-stop threads in the filling and all of the rip-stop threads in the warp being of the non-stretch type; whereby the air permeability of said parachute fabric is temporarily increased upon the opening of a parachute made therefrom, so as to reduce the initial shock to the parachute load.

4. A woven parachute fabric having both stretch type and non-stretch type rip-stop threads incorporated therein, and intersticial threads between said rip-stop threads, every third rip-stop thread in the filling being of the stretch type, the remainder of the rip-stop threads in the filling and all of the rip-stop threads in the warp being of the non-stretch type; whereby the air permeability of said parachute fabric is temporarily increased upon the opening of a parachute made therefrom, so as to reduce the initial shock to the parachute load.

5. A woven parachute fabric having both stretch type and non-stretch type rip-stop threads incorporated therein, and intersticial threads between said rip-stop threads, every third rip-stop thread in the filling and every tenth ripstop thread in the warp being of the stretch type, the remainder of the rip-stop threads in the filling and warp being of the non-stretch type; whereby the air permeability of said parachute fabric is temporarily increased upon the opening of a parachute made therefrom, so as to reduce the initial shock to the parachute load.

6. A woven parachute fabric according to claim 1, wherein said rip-stop threads are woven in pairs.

References Cited in the file of this patent UNITED STATES PATENTS 1,786,838 Fisher Dec. 30, 1930 2,254,339 Wylde et al. Sept. 2, 1941 2,384,187 Manson et a1 Sept. 4, 1945 2,574,029 Foster Nov. 6, 1951

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