GB2250961A

GB2250961A - Personal flotation device

Info

Publication number: GB2250961A
Application number: GB9126625A
Authority: GB
Inventors: Colin James Mccabe
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-12-18
Filing date: 1991-12-16
Publication date: 1992-06-24
Anticipated expiration: 2011-12-16
Also published as: GB9027447D0; GB9126625D0; GB2250961B

Abstract

A personal flotation device comprises first second and third buoyancy zones 12, 14, 16 having respective first, second and third centres of buoyancy. The first buoyancy zone 12 is adapted to be arranged in use in front of the centre of gravity of the chest of the wearer. The second zone 14 is adapted to be arranged in use on the wearer such that the second centre of buoyancy is below the first centre of buoyancy, and is displaced laterally therefrom in a first direction. The third zone 16 is adapted to be arranged in use on the wearer such that the third centre of buoyancy is above the first centre of buoyancy and is displaced laterally therefrom in a second direction opposite the first direction. A fourth buoyancy zone 18 may be provided which in use is arranged behind the wearers neck. The zones may be formed as single or dual chambers inflated by a compressed gas container 34. <IMAGE>

Description

Improvements in or relating to Personal Flotation Devices This invention relates to personal flotation devices.

Flotation devices in the form of, for example, life jackets are well known and many are provided with self righting capabilities, i.e. to ensure that the wearer is always lying face up in the water even if he or she is unconscious.

When a wearer of a standard life jacket is lying face down, the lower part of the torso must sink below the surface and then the wearer has to twist to the left or right before the jacket will perform its self righting function.

Two life jackets are disclosed in British Patent Specification No. 1560786. The first of these comprises a halter type stole having a collar portion and left and right chest lobes. The stole extends symmetrically about the wearerIs neck and chest, and one of the chest lobes has greater buoyancy than the other.

The other example comprises a stole having a collar and a single chest lode which extends down the front of the chest. In this embodiment one side of the single chest lobe has a greater buoyancy than the other. The disadvantage of such stoles is that it cannot be guaranteed that they will cause the wearer to self right when lying face down.

It is an object of this invention to obviate and/or mitigate this and other disadvantages of the prior art.

According to this invention, there is provided a personal floation device comprising: a first buoyancy zone having a first centre of buoyancy, and adapted to be arranged in use on the torso of a wearer, such that the first centre of buoyancy is arranged in front of the centre of gravity of the torso of the wearer; a second buoyancy zone having a second centre of buoyancy, and adapted to be arranged in use on the wearer such that the second centre of buoyancy is below said first centre of buoyancy of the first buoyancy zone, and is displaced laterally therefrom in a first direction; and a third buoyancy having a third centre of buoyancy, and adapted to be arranged in use on the wearer, such that the third centre of buoyancy is above the first centre of buoyancy and is displaced laterally therefrom in a second direction opposite the first direction.

Preferably the first, second and third buoyancy zones define a buoyancy member which is adapted to be arranged in use substantially diagonally across the chest of the wearer.

For the avoidance of any doubt, the floation device preferably comprises a fourth buoyancy zone adapted to be arranged in use behind the neck of the wearer to support the heard of the wearer.

The expression "front", "below", "above" and "behind" as used herein, are intended to refer to those positions as they would be when the wearer is standing upright.

In a preferred embodiment, the second centre of buoyancy is adapted to be arranged in use in the region of the abdomen of the wearer. Preferably, the third centre of buoyancy is adapted to be arranged in use in the region of the left or right shoulder of the wearer.

In a preferred embodiment, the buoyancy zones are integral and may be in the form of a single or dual inflatable chamber.

Inflation means may be provided to inflate the zones. The inflation means may be attached to the device and may be actuated automatically on contact with the water. Alternatively, the inflation means may be provided separately from the ddevice to be attached thereto at an appropriate time for inflation. The inflation means may comprises at least one compressed gas container.

Securing means may be provided to secure the device to the wearer. Preferably, the securing means comprises straps. The flotation device may form part of, or be worn in addition to, an immersion suit.

An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a personal floation device; Figs. 2 and 2a are respectively front and top plan views of a person showing the positions of first, second and third buoyancy zones of the flotation device shown in Fig. 1; Figs 3 and 3a show respectively side and front views of the person shown in Fig. 2a lying face down in the water; Figs 4 and 4a are respectively schemmatic side and front views of a person lying face down in the water and showing the forces on the person; Fig. 5 is a view similar to Fig. 4a but showing the person being twisted in the water; Fig. 6 is a Fig similar to Fig. 5 but showing the force applied to the person by the third buoyancy zone;; Fig. 7 is a view similar to Fig. 6 but showing the person after the device has perfomed its self-righting function; and Fig. 8 is a side view of a person showing a fourth buoyancy zone supporting the person's head.

Referring to the drawings, Fig. 1 shows a personal flotation device generally designated 10 which comprises a first buoyancy zone 12, a second buoyancy zone 14 and a third buoyancy zone 16. As can be seen from Figs. 2 and 2a, the first buoyancy zone 12 is adapted to be arranged on the chest of the wearer, the second buoyancy zone 14 is adapted to be arranged below the first buoyancy zone 12 and displaced laterally from the first buoyancy zone to the left side of the wearer, and a third buoyancy zone adapted to be arranged on the wearer above the first buoyancy zone and displaced laterally from the first buoyancy zone to the right side of the wearer. The personal flotation device 10 also comprises a fourth buoyancy zone 18 which is adapted to be arranged behind the neck of the wearer (see Fig. 8).

The first buoyancy zone 12 is adapted to be arranged on the torso of the wearer such that the first centre of buoyancy of the first buoyancy zone 12 is directly in front of the centre of gravity of the torso of the wearer. In this respect, reference is made to Fig. 4 which shows, schematically, the wearer lying face down in the water and the arrow 20 represents the upward buoyancy force from the first buoyancy zone 12 which passes through the centre of buoyancy of the first buoyancy zone 12. The centre of gravity of the torso of the wearer is designated 22 and the arrow designated 24 represents the downward force from the centre of gravity 22. The arrow 26 represents the upward buoyancy force from the second buoyancy zone 14 which passes through the centre of buoyancy thereof.

In view of the fact that, when the wearer is lying face down in the water, the centre of gravity of the torso is above the first centre of buoyancy of the first buoyancy zone, the body is thus in unstable equilibrium.

In view of this, the force represented by the arrow 26 from the second buoyancy zone 14 will cause the body to twist in the direction indicated by the arrow 28, which turns the body onto its right side, as shown in Fig. 5.

Referring to Fig. 6, the arrow 30 designates the upward buoyancy force from the third buoyancy zone 16 which passes through the centre of buoyancy thereof.

Thus, an upward force is provided while the body is on its right-hand side which turns the body in the direction indicated by the arrow 32 and then passes through the position shown in Fig. 7 until the body is turned completely onto its back. There is thus a continual rolling movement of the body from the position shown in Figs 3, 3a, 4 and 4a to the position where it is lying on its back. In effect, the personal flotation device 10 is able to perform its function by providing an area of buoyancy (first buoyancy zone 12) directly beneath the centre of gravity of the torso of the wearer, when the wearer is lying face down in the water. This makes the body unstable in the water and liable to tips to one side or the other. The additional areas of buoyancy namely the second and third buoyancy zones 14, 16 ensure that the body tip in one direction only, thus resulting in a continuous turning motion of the body.

Fig. 8 shows the wearer lying face up in the water with his head being supported by the fourth bouyancy zone 18.

Figs. 2 to 8 show the respective first, second, third and fourth buoyancy zones 12, 14, 16 and 18 as being separate from each other. However, it will be appreciated that, as shown in Fig. 1 the zones are all part of a single unit and may all be defined by a single or dual inflatable chamber or chambers which are inflatable by inflation means in the form of a compressed gas container 34, operated by a pull-tab which, when pulled in the direction indicated by the arrow 38 releases the gas to inflate the jacket 10. In certain situations, it may be desirable to provide to more than one bottle of compressed gas 34. A water activated fuse (not shown) may be contained in a water-tight compartment near the tab 36. When this fuse comes in contact with the water, it releases the gas in one of the bottles 34 to inflate the jacket.This has the advantage that the jacket will inflate automatically if the wearer should be unconscious on contact with the water.

The embodiment described has the advantage that it is able to self right an unconscious person who is floating face down in the water, and is able to self right a person who has been turned over by wave action.

A further advantage is that the first buoyancy zone 12 is shaped such that it diverts waves and spray away from the face of the wearer. Also, the design of the front part is such that it does not allow water to be channelled up the chest and into the wearer's face.

In order to secure the floatation device 10 to the wearer, a suitable harness is provided. The construction of such a harness would be readily appreciated by the skilled person.

Various modifications may be made without departing from the scope of the invention. For example, the second buoyancy zone 14 could be adapted to be arranged on the right side of the wearer and the third buoyancy zone 16 could be adapted to be arranged on the left side of the wearer.

Claims

Claims:

1. A personal floatation device comprising: a first buoyancy zone having a first centre of buoyancy, and adapted to be arranged in use on the torso of the wearer such that said first centre of buoyancy is arranged in front of the centre of gravity of the torso of the wearer; a second buoyancy zone having a second centre of buoyancy, and adapted to be arranged in use on the wearer such that said second centre of buoyancy is below said first centre of buoyancy, and is displaced laterally therefrom in a first direction; and a third buoyancy zone having a third centre of buoyancy adapted to be arranged in use on the wearer such that said third centre of buoyancy is above said first centre of buoyancy and is displaced laterally therefrom in a second direction opposite the first direction.

2. A personal floatation device according to Claim 1 and including a fourth buoyancy zone adapted to be arranged in use behind the neck of the wearer to support the head of the wearer.

3. A personal floatation device according to Claim 1 or 2 wherein the second centre of buoyancy is adapted to be arranged in use in the region of the abdomen of the wearer.

4. A personal flotation device according to Claim 1, 2 or 3 wherein the third centre of buoyancy is adapted in use to be arranged in the region of the left or right shoulder of the wearer.

5. A personal flotation device according to any preceding Claim wherein the zones are in the form of a single or dual inflatable chamber.

6. A personal floatation device according to any preceding claim wherein inflation means is provided to inflate the zones.

7. A personal flotation device according to Claim 6 wherein the inflation means comprises at least one compressed gas container.

8. A personal floation device substantially as herein described with reference to and as shown in the accomanying drawings.

9. Any novel subject matter or combination including novel subject matter disclosed in the foregoing specification or claims and/or shown in the drawings, whether or not within the scope of or relating to the same invention as any of the preceding claims.