Parachutes

Information

  • Patent Grant
  • 6769650
  • Patent Number
    6,769,650
  • Date Filed
    Thursday, April 3, 2003
    21 years ago
  • Date Issued
    Tuesday, August 3, 2004
    20 years ago
Abstract
A parachute has a canopy and rigging lines with skirt assist lines connected between a point on each rigging line adjacent a lower edge of the canopy and a point on the interior of the canopy spaced from the lower edge. The arrangement is such that a portion of the canopy between the point and the lower edge is relieved of tension as the canopy is deployed to assist the opening of the canopy. The skirt assist lines are frangible. This prevents rapid deployment of the canopy to lower g-forces on the load in high speed opening.
Description




BACKGROUND TO THE INVENTION




1. Field of the Invention




The invention relates to parachutes.




2. Brief Review of the Prior Art




The term “parachutes” is intended to cover any type of parachute provided with a canopy with rigging lines connecting the canopy to a load. When such a parachute is deployed, air enters the canopy of the parachute and inflates the canopy. When the canopy is deployed at low speeds and at low levels, the inflation may not be sufficiently rapid to ensure satisfactory opening. In order to improve the opening, it is known to provide a plurality of skirt assist lines. Each skirt assist line extends between a respective rigging line and a respective point on the interior of the canopy such that a portion of the canopy between the point and the lower edge of the canopy is relieved of tension as the canopy is deployed. As a result, this portion of the canopy spreads very rapidly and assists in rapid opening of the remainder of the canopy.




It is a problem with such skirt assist lines that, at higher speeds, the rapid deployment of the portion of the canopy between the connection points of the skirt assist lines and the lower edge of the canopy can induce g-forces on a load which are undesirable. The load may be a parachutist or cargo. This is particularly true where the load is a person and can occur, for example, where the parachute forms part of an ejection seat which may be deployed at high or low levels and at high or low speeds.




SUMMARY OF THE INVENTION




According to the invention, there is provided a parachute comprising a canopy having a lower edge, rigging lines connecting the canopy to a load, and a plurality of skirt assist lines, each skirt assist line extending between a respective rigging line and a respective point on the interior of the canopy such that a portion of the canopy between the point and the lower edge is relieved of tension as the canopy is deployed to assist the opening of the canopy, the skirt assist lines being frangible.




By making the skirt assist lines frangible, the skirt assist lines can be rendered inoperative in circumstances where their operation would cause undesirable g-forces.




The following is a more detailed description of an embodiment of the invention, by way of example, reference being made to the accompanying drawings in which:—











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a schematic view of a parachute showing a canopy of the parachute in a first stage of deployment and rigging lines for connection to a load with skirt assist lines extending between the rigging lines and the canopy,





FIG. 2

is a similar view to

FIG. 1

but showing the skirt assist lines broken.











DESCRIPTION OF THE PREFERRED EMBODIMENTS




Referring first to

FIG. 1

, the parachute comprises a canopy indicated diagrammatically at


10


by rigging lines, some of which are shown at


11


, attached to a parachutist or cargo shown schematically at


18


. The canopy


10


has a lower edge


12


and an apex


13


and may be of any suitable construction. In general, the canopy will be formed by gores (not shown) interconnected by seams.




The canopy


10


may be of any known shape and be for any intended purpose. For example, the canopy may be generally conical and may be deployed by static line or used in free fall. The canopy may be provided as part of an aircraft ejection seat.




The parachute is provided with skirt assist lines


15


. Each skirt assist line


15


is connected between a rigging line


11


and the canopy


10


. The connection is between a point


16


on the rigging line


11


adjacent the lower edge


12


of the canopy and a point


17


on the interior of the canopy


10


spaced from the lower edge


12


. The length of each skirt assist line


15


is less than the distance between the points


16


,


17


along the associated rigging line


11


and along the canopy


10


. In general, the connection point


17


on the canopy will be along a main seam between two adjacent gores of the canopy


10


. There may be a skirt assist line


15


between every rigging line


11


and the canopy


10


or only between some rigging lines


11


and the canopy.




In use, the canopy


10


and the rigging lines


11


are packed in a deployment bag or container (not shown) from which the canopy


10


is deployed. As indicated above, this deployment may be manual or automatic. On deployment, the canopy


10


streams from the deployment bag or container and adopts the uninflated disposition shown in FIG.


1


. The effect of the skirt assist lines


15


is to relieve from tension the portion of the canopy


10


between the lower edge


12


and the points


17


of connection of the skirt assist lines


15


on the canopy


10


. This allows this portion of the canopy


10


to move outwardly rapidly in the air flow to promote fast inflation of the canopy. This is particularly advantageous when deployment is at low level and/or low speed.




The skirt assist lines


15


are frangible. The purpose of this is to prevent the portion of the canopy


10


between the lower edge


12


and the points


17


of connection of the skirt assist lines


15


on the canopy


10


from moving outwardly on deployment of the canopy


10


. This is desirable when the canopy


10


is deployed at high speeds in order to prevent the parachutist or other load


18


, being subjected to undesirably high g-forces. Under such circumstances, the higher speed of deployment is sufficient to ensure satisfactory inflation of the canopy


10


.




The skirt assist lines


15


may be made frangible and or severable in a number of ways and at any point.




First, each skirt assist line


15


may be provided with a weak point designed to break under a predetermined load equivalent to that experienced by the rigging line


11


when the canopy


10


opens at high speed. Accordingly, on such high speed opening of the canopy


10


, the skirt assist lines


15


break at the weak points to prevent rapid outward opening of the portion of the canopy


10


between the lower edge


12


and the points


17


of connection of the skirt assist lines


15


on the canopy


10


. The g-forces on the load are thus reduced.




As an alternative to weak points, each skirt assist line


15


may be provided with a device that severs the skirt assist line


15


when high speed opening loads are sensed. This achieves the same effect as the weak points.




Additionally or alternatively, the skirt assist lines


15


may be able to be broken prior to deployment of the canopy


10


. For example, the skirt assist lines


15


may be severable at any time before deployment.



Claims
  • 1. A parachute comprising a single canopy having a lower edge, rigging lines connecting the canopy to a load and a plurality of skirt assist lines, each skirt assist line extending between a respective rigging line and a respective point on an interior of the canopy such that a portion of the canopy between the point and the lower edge is relieved of tension as the canopy is deployed to assist the opening of the canopy, the skirt assist lines being frangible such that, upon breaking of said skirt assist line, said canopy portion is prevented from moving outwardly on deployment, thereby slowing an initial rate of canopy inflation.
  • 2. The parachute according to claim 1 wherein the skirt assist lines are broken prior to deployment of the canopy to prevent rapid outward opening of said portion of the canopy between the point and the lower edge.
  • 3. The parachute according to claim 1 wherein the skirt assist lines are broken during deployment of the canopy only if the load in the skirt assist lines exceeds a predetermined maximum and otherwise remain unbroken throughout canopy deployment.
  • 4. The parachute according to claim 1 wherein each skirt assist line includes a weak point designed to break the associated skirt assist line if the load in the skirt assist line exceeds a predetermined maximum.
  • 5. The parachute according to claim 2 wherein each skirt assist line is severed.
  • 6. The parachute according to claim 3 wherein means are associated with each skirt assist line for severing the skirt assist line when high speed opening loads are sensed.
  • 7. A parachute comprising a canopy having a lower edge, rigging lines connected to the canopy at first points along said lower edge to support a load, and a plurality of skirt assist lines each extending between a second point on a respective rigging line spaced from its lower edge first point and a respective third point on an interior of the canopy spaced from said lower edge first point such that a portion of the canopy between said third point and the lower edge is relieved of tension as the canopy is deployed to assist opening of the canopy lower edge, said skirt assist lines being frangible such that, upon breaking of said skirt assist lines, said canopy portion is prevented from moving outwardly on deployment, thereby slowing an initial rate of canopy inflation preventing the load from being subjected to undesirably high g-forces.
  • 8. The parachute according to claim 7 wherein the skirt assist lines are broken prior to deployment of the canopy to prevent rapid outward opening of said portion of the canopy between the third point and the lower edge.
  • 9. The parachute according to claim 7 wherein the skirt assist lines are broken during deployment of the canopy if the load in the skirt assist lines exceeds a predetermined maximum.
  • 10. The parachute according to claim 7 wherein the skirt assist lines are broken during deployment of the canopy only it the load in the skirt assist lines exceeds a predetermined maximum and otherwise remain unbroken throughout canopy deployment.
Priority Claims (1)
Number Date Country Kind
0030396 Dec 2000 GB
Parent Case Info

This application is a continuation of Ser. No. 10/013,834 filed Dec. 13, 2001 now abandoned.

US Referenced Citations (12)
Number Name Date Kind
1872705 Elliott Aug 1932 A
2523276 Buhler Sep 1950 A
3110459 Heinrich Nov 1963 A
3385539 Ewing et al. May 1968 A
3420478 Ferguson Jan 1969 A
3586269 Hensley Jun 1971 A
4586685 Kostelezky May 1986 A
4955563 Lee et al. Sep 1990 A
5248117 Hennings Sep 1993 A
5388787 Webb et al. Feb 1995 A
6003815 Parker et al. Dec 1999 A
6276638 Parker et al. Aug 2001 B1
Foreign Referenced Citations (7)
Number Date Country
0 861 783 Sep 1998 EP
266345 Jul 1927 GB
552895 Apr 1943 GB
776296 Jun 1957 GB
2 102 357 Feb 1983 GB
2 220 626 Jan 1990 GB
9961315 Dec 1999 WO
Continuations (1)
Number Date Country
Parent 10/013834 Dec 2001 US
Child 10/406005 US