GB2222121A - Improvements relating to parachutes - Google Patents

Abstract

A parachute having a canopy which has inherent drive means which provides lateral thrust in use and which supports a load or parachutist through rigging lines has means 10 for causing the canopy to descend to ground or sea level when the load/parachutist lands with the initial orientation of the canopy such that the drive means acts to urge the canopy upwardly. This may be achieved in several ways by for example causing the canopy to rotate about the rigging lines, e.g. by a non- symmetrical slot 12, so that the thrust from the drive means no longer acts to urge the canopy upwardly. It is also possible to reduce or remove the drive thrust upon landing by suitable means to allow the canopy to descend. <IMAGE>

Description

Improvements relating to parachutes This invention relates to the field of parachutes.

More particularly this invention relates to parachutes with inherent drive.

It is well known in the art to provide parachutes with inherent drive whereby a component of lateral thrust is produced by the parachute in a direction generally perpendicular to the direction of descent.

There are a large number of known different configurations of parachute which may possess inherent drive, e.g. vents or blow holes may be provided in a lower part of the canopy. Such parachutes have the significant advantage of being steerable and allow a parachutist an improved degree of control over the path of descent. This may for example allow the parachutist to steer a path avoiding dangers such as power lines and roads.

It is desired with all parachutes that when the parachutist/load has landed either on the ground or in the water then the canopy should be collapsed as auickly as possible so as to avoid the parachutist/ load being dragged by the parachute. In normal circumstances the parachute tends to be blown away from the parachutist/load in a downwind direction by any wind. The canopy will then, under the influence of the wind and the tension in the rigging lines, swing downwards and foul the ground or contact the water and thus be collapsed. This collapse on contacting the ground or water may be assisted by the provision of devices such as water pockets and the like. Water pockets are disposed around the edge of the canopy and have openings facing the apex of the canopy.

When the edge of the parachute touches the water the water pockets fill with water and act as an anchor at that point serving to weigh down the rim, thereby more rapidly collapsing the parachute.

It has however now been recognised that under certain circumstances problems can arise with the collapse of a parachute with inherent drive. The thrust produced by the parachute to give it drive can, depending on the orientation of the parachute, act to hold the canopy clear of the water or ground when the parachutist/load lands. The parachute may then act like a kite and drag the parachutist/load through the water or across the ground which is clearly undesirable and dangerous. The problem is particularly significant in the case of emergency escape parachutes in which case the parachutist may be unconscious or injured and unable to assist himself. If the parachute deployment is above water then the problem is also compounded since the lack of any fixed objects means the parachutist has nothing to hold on to and the canopy will not be fouled and thereby caused to collapse.In such circumstances an injured parachutist or load could be dragged for hundreds of meters through the water.

In accordance with the present invention there is provided, a parachute comprising a canopy with inherent drive means adapted to provide a degree of lateral thrust in use, rigging lines for coupling a parachutist/load to said canopy and means associated with said canopy and/or rigging lines for automatically causing or allowing said canopy to descend to ground or sea level when, in use, the parachutist/load lands with the initial orientation of said canopy being such that said inherent drive means initially acts to urge said canopy upwardly.

It is envisaged that the means for causing or allowing the parachute to descend may take a number of different forms. In one preferred embodiment means are provided to automatically rotate the parachute canopy about the rigging lines so that the direction of the thrust produced by the canopy is no longer acting to hold the canopy clear of the ground/water. This provides a simple and effective arrangement in which the drive means is automatically utilised to provide a downward force for assisting the canopy to descend.

In one possible arrangement the means for automatically rotating the canopy can be operative to provide a permanent rotational thrust to the canopy. Upon landing therefore, the canopy rotates until the drive means acts downwardly whereupon the canopy is brought down to land or sea level.

The canopy can for example be provided with an open slit between gores, the length of one side of the slit being greater than the length of the other side of the slit so that the air escapes through the slit in a direction which causes the canopy to rotate. Such an arrangement is simple to construct being only a slight modification to a standard canopy and yet is a most effective and inherently reliable method of assisting the canopy to descend to the ground/water on landing. Such an arrangement will of course cause the parachute to rotate whilst descending as well as upon landing and if the parachutist did not intervene then the parachute would have a helical path of descent.

If the parachutist so wished, the parachute could be manually steered to counter this inherent rotation and the parachute could be made to behave as a normal steerable parachute.

Another possible arrangement of the means for automatically rotating the canopy is to provide the canopy with drive slots configured such that the thrust produced by air escaping from the canopy gives the canopy a degree of rotation upon landing.

Once again this feature can be provided with only a slight modification to a standard parachute and as the modification is built into the canopy itself the modification is both inexpensive and reliable.

A further arrangement for automatically rotatinq the canopy which is particularly suitable as an add-on modification to standard inherent drive parachutes is to provide an anchor means for coupling to a steering line of the parachute so that upon landing the anchor means produces a tension in the steering line which is operative to rotate the canopy to an orientation in which the drive means acts downwardly. It can be seen that such a modification could easily and inexpensively be carried out to existing parachutes.

Preferred embodiments of the anchor means are of the form of an auxiliary parachute/sea anchor.

These would be particularly effective if the landing is in water in which case the auxiliary parachute/sea anchor fills with water and provides a strong pull on the steering line as the parachutist/load starts to be dragged through the water.

Alternative embodiments of the invention in which a canopy of a parachute with inherent drive means is caused to descend upon landing include means for automatically reducing or removing the driving thrust produced by the drive means of the parachute upon landing. Such a means is intended to result in the thrust thereafter being insufficient to hold the canopy clear of the ground/water so that it is then allowed to descend by swinging downwardly under the influence of wind and tension in the rigging lines.

In a preferred arrangement the means may comprise an anchor means coupled by a tie line to the drive vents or blow holes in the canopy in such a way that upon landing the anchor means produces a tension in the tie line which is operative to at least partially close the drive vents or blow holes. An advantage of this arrangement is that it is again possible to modify an existing canopy to have this feature in a relatively simple and inexpensive manner.

In a particularly preferred arrangement, the tie line is divided into two branching lines at its end distal to the anchor means and each of the ends of the branching lines is attached to a different point on the canopy such that tension in the tie line draws these points together and serves to at least partially close the drive vents/blow holes of the canopy.

Other preferred features are that the branch lines should be slidably attached to at least one other point on the canopy along their length.

This arrangement increases the collapsing effect produced by the tension in the tie line and is referred to as a purse string arrangement. A particularly effective purse string arrangement is one in which the ends of the branch lines are attached to points at the periphery of the canopy and the sliding attachments are also at the periphery of the canopy. The anchor means may have any of the forms previously discussed.

A further means in accordance with the invention whereby the canopy of an inherent drive parachute can be caused to descend is to couple an anchor means via a tie line to the canopy or rigging lines such that tension in the tie line produced upon landing pulls the canopy downwards.

One such arrangement would be to have an additional auxiliary parachute coupled to the periphery of the canopy. Such a modification could again be simply and inexpensively made to an existing inherent drive parachute.

Another possible arrangement is to make use of the auxiliary parachute which is provided in traditional parachutes to extend the canopy and rigging lines during deployment. For maximum effectiveness such auxiliary parachutes are usually attached by relatively short lines to the apex of the canopy.

Unmodified such auxiliary parachutes would not therefore assist the canopy to descend because the line joining it to the canopy is too short to allow it to fill with water or foul the ground.

However, by providing means for automatically extending the line joining the auxiliary parachute to the canopy after the auxiliary parachute has fulfilled its function during deployment then the auxiliary parachute will reach the water or ground on landing and will be potentially effective to cause the canopy to descend. The line joining the auxiliary parachute to the canopy may be of a length sufficient to allow the auxiliary parachute to reach the water/ ground but can be provided with a frangible element coupling two spaced parts of the line together so as to reduce the effective length of the line, the frangible element being adapted to be broken once the auxiliary parachute has performed its function during deployment.

The various means discussed above for causing the parachute to descend may be provided in addition to pockets adapted to collapse the parachute more quickly once it has reached water level in the case of deployment over the sea.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 illustrates the action of a non-driven standard parachute upon landing.

Fig. 2 illutrates the problem which can arise with parachutes with inherent drive upon landing.

Fig. 3 illustrates a first embodiment of a parachute modified to overcome the problem illustrated in Fig. 2 by virtue of an open slot in the canopy imparting rotation to the canopy.

Fig. 4 illustrates a second embodiment of a parachute modified to overcome the problem illustrated in Fig. 2 by virtue of assymetric driving vents imparting rotation to the canopy.

Fig. 5 illustrates a third embodiment of a parachute modified to overcome the problem illustrated in Fig. 2 by virtue of an anchor attached to a steering line of the parachute to impart rotation to the canopy upon landing.

Figs. 6a and 6b illustrate a fourth embodiment of a parachute modified to overcome the problem illustrated in Fig. 2 by virtue of an anchor coupled to the driving vents of the parachute in a manner which partially blocks the driving vents upon landing.

Fig. 7 illustrates a fifth embodiment of a parachute modified to overcome the problem illustrated in Fig. 2 by virtue of an anchor coupled to the periphery of the canopy which pulls the canopy down upon landing.

Figs. 8a, 8b and 8c illustrate a sixth embodiment of a parachute modified to overcome the problem illustrated in Fig. 2 by virtue of a modification to the line coupling the auxiliary parachute which aids deployment of the main canopy, whereby the auxiliary parachute is made able to pull the canopy downwards upon landing.

Throughout the figures and the description which follows the same reference numerals have been used to designate the same elements in each of the different parachutes.

Fig. 1 illustrates the action of an undriven parachute upon landing in the sea. The canopy 2 is pulled away from the parachutist 4 by the action of any wind. The combined action of the wind, the tension in the rigging lines 8 and gravity then causes the canopy 2 to decend towards the water. Water pockets 6 disposed around the periphery of the canopy 2 have open slots facing the apex of the canopy 2 and are filled with water when they touch the water surface. The weight of the water in these water pockets 6 then serves to hold the canopy 2 in contact with the water and rapidly collapses the canopy 2.

Fig. 2 illustrates the problem which can occur with parachutes with inherent drive means upon landing. The parachutist 4 has landed in the water and under the influence of the wind, the tension in the rigging lines 8 and gravity the canopy has started to decend towards the water.

When the canopy reaches the position shown in Fig. 2, the driving thrust produced by the driving vents 10 has a component which acts to hold the canopy 2 up against the combined forces of the crosswind, the tension in the rigging lines 8 and gravity.

Whilst the parachute is in this disposition the parachutist 4 is subject to the tension in the rigging line 8 which drags him through the water.

The parachute may maintain the disposition illustrated in Fig. 2 for some time resulting in the parachutist 4 being dragged for a considerable distance through the water. It is highly undesirable that the parachutist 4 should be dragged through the water in this way.

Fig. 3 illustrates a first embodiment of a parachute modified to overcome the problem illustrated in Fig. 2. The canopy 2 has an open slot 12 between adjacent gores forming the canopy 2. One side of the open slot 12 is longer than the other side which means that the air escaping through the open slot 12 will have a component of its motion in a direction parallel to the plane of the periphery of the canopy 2. The thrust produced by the air escaping through the open slot 12 wfll impart a slow rotation to the canopy 2. Thus, when the parachutist 4 lands in the water the canopy 2 will slowly rotate and the thrust produced by the driving vents 10 will not permanently be acting in a direction holding the canopy 2 above the water. Once the drive vents act downwardly the canopy 2 will descend to the water and be collapsed by the water pockets 6.

Fig. 4 illustrates a second embodiment of a parachute modified to overcome the problem illustrated in Fig. 2. The canopy 2 has been modifved by the provision of assymetric drive slots 10. The assymetric drive slots 10 mean that the air escaping through the drive slots produces a resultant total thrust which acts to rotate the canopy 2 when the parachutist 4 has landed in the water. As explained in connection with Fig. 3 the rotation of the canopy 2 ensures that the canopy 2 descends to the water and is rapidly collapsed. The assymetry in the driving slots 10 in Fig. 4 is of the form that the area of one of the driving slots is larger than the area of the other driving slots. This is only one possibility for the assymetry.One way of viewing the required assymetry is to consider the plane 12 passing through the parachutist 4, the apex of the canopy 2 and the highest part of the periphery of the canopy 2 when the parachutist 4 has landed in the water. If the amount of thrust produced by the driving slots on either side of plane 12 is unequal then the canopy 2 will be caused to rotate in the desired manner. It will be apparent to those skilled in the art that there are many possible ways in which the thrust on either side of the plane 12 could be made unequal.

Fig. 5 illustrates a third embodiment of a parachute modified to overcome the problem illustrated in Fig. 2. An anchor 14 in the form of an auxiliary parachute is coupled to a steering line 16 by a tie line 18. When the anchor 14 fills with water it produces a tension in the tie line 18 which acts upon the steering line 16 and causes the canopy 2 to rotate by virtue of the standard steering method for such parachutes with inherent drive. The canopy 2 will then be collapsed in accordance with the process described in relation to Fig. 3.

Figs. 6a and 6b illustrate a fourth embodiment of a parachute modified to overcome the problem illustrated in Fig. 2. An anchor 14 is attached to a tie line 20 which splits into two branching lines 22. The ends 24 of the branching lines 22 are attached to spaced points on the periphery of the canopy 2. The driving vents 10 are positioned between the spaced points 24. The branching lines 22 slidingly pass through a number of loops 26 secured to points along the periphery of the canopy 2 between the spaced points 24. During the normal descent illustrated in Fig. 6 there is no tension in the tie line 20 and the driving vents 10 are fully opened imparting a driving thrust to the parachute.

When the parachutist lands as is illustrated in Fig. 6b the anchor 14, in this case an auxiliary parachute, fills with water and exerts a tension on tie line 20. The resulting tension in the branching lines 22 pulls the spaced ends 26 of the branching lines 22 together thereby partially blocking the driving vents 10. The driving thrust produced by the driving vents 10 is thus reduced and is insufficient to hold the canopy 2 clear of the water. The canopy 2 therefore descends and touches the water where it is rapidly collapsed by the action of the water pockets 6.

Fig. 7 illustrates a fifth embodiment of a parachute modified to overcome the problem illustrated in Fig. 2. An anchor 14, in this case in the form of an auxiliary parachute, is coupled to the periphery of the canopy 2 by a tie line 28. When the parachu tist 4 lands in the water the anchor 14 fills with water and exerts a tension in tie line 28 which pulls the canopy 2 downwards to touch the water in opposition to the thrust being produced by the driving vents 10 in a direction tending to hold the parachute up. The water pockets 6 then act to rapidly collapse the canopy 2.

Figs. 8a, 8b and 8c illustrate a sixth embodiment of a parachute modified to overcome the problem illustrated in Fig. 2. An auxiliary parachute 30 is disposed to aid deployment of the canopy 2 in the usual manner by pulling the canopy 2 and the rigging lines 8 clear of the parachutist 4 upon deployment. The auxiliary parachute 30 is coupled to the canopy 2 by a modified tie line 32. A frangible element 34 initially join two spaced points on the tie line 32 to thereby reduce the effective length of the tie line 32 to that usually used with a deployment assisting auxiliary parachute to produce the best effect. As illustrated in Fig. 8a the auxiliary parachute 30 acts on the canopy 2 and the rigging lines 8 via the shortened tie line 32 to assist in the deployment of the canopy 2. A predetermined time after deployment the frangible element 34 is caused to break by, for example, a cutter. The tie line 32 is thus extended to a length well in excess of that usually used with deployment assisting auxiliary parachutes as is illustrated in Fig. 8b. When the parachutist 4 lands in the water, as is illustrated in Fig. 8c, the auxiliary parachute 30 fills with water which produces a tension in the tie line 32 which acts to pull the canopy 2 downwards towards the water in opposition to the upward lifting thrust produced by the driving vents 10. When the canopy 2 touches the water it is rapidly collapsed by the water pockets 6.

Claims (20)

CLAIMS:

1. A parachute comprising a canopy with inherent drive means adapted to provide a degree of lateral thrust in use, rigging lines for coupling a parachutist/load to said canopy and means associated with said canopy and/or rigging lines for automatically causing or allowing said canopy to descend to ground or sea level when, in use, the parachutist/load lands with the initial orientation of said canopy being such that said inherent drive means initially acts to urge said canopy upwardly.

2. A parachute as claimed in claim 1 wherein said means for causing or allowing the parachute to descent comprises means which automatically rotate the parachute canopy about the rigging lines.

3. A parachute as claimed in claim 2 wherein said means for automatically rotating the parachute canopy provide a permanent rotational thrust to the canopy.

4. A parachute as claimed in claim 3, wherein said canopy is provided with an open slit between gores, the length of one side of the slit being greater than the length of the other side of the slit so that the air escapes through the slit in a direction which causes the canopy to rotate.

5. A parachute as claimed in claim 2 wherein the canopy is provided with drive slots configured such that the thrust produced by air escaping from the canopy gives the canopy a degree of rotation upon landing.

6. A parachute as claimed in claim 2 wherein an anchor means is provided for coupling to a steering line of the parachute so that upon landing the anchor means produces a tension in the steering line which is operative to rotate the canopy to an orientation in which the drive means acts downwardly.

7. A parachute as claimed in claim 6 wherein said anchor means comprises an auxiliary parachute/sea anchor.

8. A parachute as claimed in claim 1 comprising means for automatically reducing or removing the driving thrust produced by the drive means of the parachute upon landing.

9. A parachute as claimed in claim 8 wherein said means for automatically reducing or removing the driving thrust comprises an anchor means coupled by a tie line to the drive vents or blow holes in the canopy in such a way that upon landing the anchor means produces a tension in the tie line which is operative to at least partially close the drive vents or blow holes.

10. A parachute as claimed in claim 9. wherein said tie line is divided into two branching lines at its end distal to the anchor means and each of the ends of the branching lines is attached to a different point on the canopy such that tension in the tie line draws these points together and serves to at least partially close the drive vents/blow holes of the canopy.

11. A parachute as claimed in claim 10 wherein said branch lines are slidably attached to at least one other point on the canopy along their length.

12. A parachute as claimed in claim 11 wherein the ends of the branch lines are attached to points at the periphery of the canopy and the sliding attachments are also at the periphery of the canopy.

13. A parachute as claimed in claim 1 wherein an anchor means is coupled via a tie line to the canopy or rigging lines such that tension in the tie line produced upon landing pulls the canopy downwards.

14. A parachute as claimed in claim 13 wherein an additional auxiliary parachute is coupled to the periphery of the canopy.

15. A parachute as claimed in claim 13 comprising an auxiliary parachute for extending the canopy and rigging lines during deployment wherein means is provided for automatically extending the line joining the auxiliary parachute to the canopy after the auxiliary parachute has fulfilled its function during deployment.

16. A parachute as claimed in claim 15 wherein the line joining the auxiliary parachute to the canopy is of a length sufficient to allow the auxiliary parachute to reach the water/ground and is provided with a frangible element coupling two spaced parts of the line together so as to reduce the effective length of the line, the frangible element being adapted to be broken once the auxiliary parachute has performed its function during deployment.

17. A parachute as claimed in any preceding claim further comprising pockets adapted to collapse the parachute more quickly once it has reached water level in the case of deployment over the sea.

18. A parachute substantially as hereinbefore described with reference to Figure 3 of the accompanying drawings.

19. A parachute substantially as hereinbefore described with reference to Figure 4 of the accompanying drawings.

20. A parachute substantially as hereinbefore described with reference to Figures 8a, 8b and Sc of the accompanying drawings.

20. A parachute substantially as hereinbefore described with reference to Figure 5 of the accompanying drawings.

21. A parachute substantially as hereinbefore described with reference to Figures 6a and 6b of the accompanying drawings.

22. A parachute substantially as hereinbefore described with reference to Figure 7 of the accompanying drawings.