WO1999037535A1

WO1999037535A1 - A buoyancy device

Info

Publication number: WO1999037535A1
Application number: PCT/NZ1999/000008
Authority: WO
Inventors: Thomas Rex Haskell; Christopher James Connell
Original assignee: Rhumbline Limited
Priority date: 1998-01-23
Filing date: 1999-01-22
Publication date: 1999-07-29
Also published as: AU2079199A

Abstract

A buoyancy device (10, 30) has an external surface (32) and a plurality of radar reflective materials (25, 27, 29, 38) provided internally of the external surface.

Description

A BUOYANCY DEVICE Field of the Invention

The present invention relates to a buoyancy device. In particular, although not exclusively, the invention relates to radar detectable life saving devices such as life rafts and life vests. However, the invention is not restricted in its use to lifesaving apparatus and may be applied to any buoyant device used in connection with waterborne craft.

Background to the Invention

Life saving and signalling devices incorporating radar reflective material are already known. US Patent No. 5,421,287 discloses a signalling device for attachment to a life- vest. The device comprises a streamer made from flat, flexible, inherently buoyant material which is normally rolled up into a water-release container secured to the life vest. While the streamer can be made of radar reflective material, an inherent disadvantage of this device is that it presents a reflective surface in substantially only one plane. The effectiveness of the radar reflective material and hence the signalling device is therefore not great which minimises the chances of locating the missing person. The device may also suffer from deployment problems, especially in rough seas or if the user is not in a fully conscious state.

UK Patent Application No. 2039120 discloses a marking device in the form of a balloon used to indicate the position of persons in distress. The balloon is stored in a container together with a gas cartridge used to inflate the balloon. The outside of the balloon is provided with metal strips which reflect radar beams. While the radar reflective material is located on a spherical surface, this device still does not achieve maximum effectiveness for reflecting radar as the surface area of the reflective material is small in comparison to the overall size of the balloon.

It is therefore an object of the present invention to provide a buoyancy device which overcomes or ameliorates at least some of the above-mentioned disadvantages or provides the public with a useful choice.

Summary of the Invention

In accordance with an aspect of the present invention there is provided a buoyancy device having an external surface and a plurality of radar reflective surfaces provided internally of the external surface.

SUBSTITUE SHEET Rule 26 The buoyancy device may comprise any object associated with waterborne craft which will remain buoyant in the event of a marine accident or a person otherwise becoming lost at sea. As such, the buoyancy device may comprise a float or a boat fender. The invention may also be embodied in a navigational buoy.

The invention may also be realised in small recreational craft such as surfboards, windsurfers or kayaks.

At present, the preferred application of the invention is in a life saving device such as a life raft or a life vest.

Suitably, the buoyancy device will be inherently buoyant or is one which may be inflated whereupon the device is buoyant. The buoyancy device may be made up of solid buoyancy material which basically defines the external surface of the device although an outer cover may be provided. Alternatively, the buoyancy device may be permanently inflated, for example, having a rigid sealed casing.

In another embodiment of the invention the buoyancy device is inflatable and as such may be stowed in a collapsed configuration. Advantageously, a gas supply may be provided together with automatic inflation means. Supplementary manual inflation means may also be provided to ensure that the user can reinflate the device should any leakage occur during use.

The external surface of an inherently buoyant device will define a three dimensional body. The external surface, i.e. the case of an inflatable buoyancy device will also define a three dimensional body upon inflation. The plurality of radar reflective surfaces may be distributed/arranged/dispersed throughout the body in an ordered or an irregular manner. An ordered manner may be achieved by arranging the reflective material into an array or a three dimensional lattice arrangement.

Alternatively, the surfaces may be arranged/dispersed at random.

The reflective surfaces may be uniformly spaced, for example arranged in a regular array. Alternatively, the reflective surfaces may be dispersed in concentrated parts or regions, for example in the uppermost portions of the buoyancy device.

Preferably, there are a very large number of radar reflective surfaces and/or the combined surface area of the radar reflective surfaces is large. It will be appreciated that a large surface area of radar reflective material relative to the external surface area or the overall size of the device will result in good radar locatability, given the size of the device. It is also preferred that the radar reflective surfaces are oriented in a plurality of different directions to maximise the effective radar reflectivity. In a most preferred form of the invention the device will include a multiplicity of radar reflective surfaces each extending in a differently oriented plane.

In one preferred form of the invention, the radar reflective surfaces are defined by a dispersion of relatively small reflective particles such as metal shavings. Such a dispersion of small particles is particularly appropriate for buoyancy devices comprised of solid buoyancy material as the small particles may be held in suspension in the solid buoyancy material. For example, the buoyancy device may include expanded polystyrene foam with aluminium shavings set into the foam.

The radar reflective surfaces may comprise a number of large substantially planar surfaces. For example, the substantially planar surfaces may be provided by sheets of radar reflective materials such as metal foil. Preferably, the substantially planar surfaces extend transversely to at least one major surface of the device. These reflective surfaces may be provided by way of baffles or partitions extending internally of the body. For example, the device may include a series of spaced longitudinal baffles with web portions extending between adjacent baffles.

The substantially planar surfaces may be substantially flat or provided with a three dimensional surface pattern. For example, the sheet material comprising the planar surfaces may be striated, pressed, crimpled or punctured.

In the form of the invention comprising relatively large planar surfaces, solid buoyant material may be disposed between the sheet members defining the planar surfaces. However, this form of the invention is preferably used in connection with inflatable buoyancy devices such as life vests or life rafts. As with the material defining the inflatable buoyancy devices, the internal members defining the reflective surfaces should be foldable or collapsable to facilitate stowage of the buoyancy devices. In one form of the invention, the reflective material may be foldable in a concertina fashion. In an alternative form of the invention, sheets of the reflective material may contain an arrangement of slits enabling each sheet to be extended generally in the plane of the sheet. In a most preferred form of the invention, the radar reflective material is compactable in the manner of expandable festoonery. This is comprised of multiple sheets e.g. foil, whereby adjacent sheets are connected to each other to from an assembly which is expandable from a collapsed to an expanded three-dimensional configuration, with adjacent sheets lying next to each other in the collapsed configuration. Preferably, the expansion of the assembly of foil sheets occurs automatically as the inflatable life jacket/life raft is deployed.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

Brief Summary of the Drawings

In order that the invention may be fully understood, some embodiment will now be described by way of example with reference to the drawings in which :

Figure 1 is a perspective, partially cut-away view of a preferred inflatable life jacket made in accordance with the present invention;

Figure 2 is a perspective, partially cut-away view of a preferred float made in accordance with the present invention; and Figure 3 is a plan view of a sheet of radar reflective material shown in collapsed configuration (a) and expanded configuration (b)

Best Mode(s) for Carrying out the Invention

The figure illustrates a life vest (10) having a conventional shape including right and left- hand chest pads (12, 14) interconnected by a neck portion (16). The life vest (10) has two front ties (18) which ensure that the right-hand and left-hand pads (12, 14) remain together during use. A waist strap (20) is provided to extend around the user's waist (not shown) to retain the life jacket (10) firmly in place during use.

The life jacket (10) may be stowed in a permanently inflated condition. Alternatively, automatic inflation means (not shown) may be provided. It can be seen that the life jacket (10) includes a manual inflation means (22) to supplement the gaseous content of the life jacket (10) in the event that any leakage occurs.

The invention resides in the internal structure of the life jacket (10). It can be seen to comprise of a number of longitudinally extending baffles (25) which are oriented perpendicularly to the front surface of the life jacket (10). The baffles (25) are substantially evenly spaced across the breadth of the life jacket. The internal structure also includes web portions (27) extending between adjacent longitudinal baffles. Web portions (29) are also arranged to extend between the outermost longitudinal baffles and the side edges of the life j acket (10).

Each of the baffles and webs is comprised of metal foil or laminate including a metal or otherwise radar reflective layer. It can be seen that the large number of baffles and webs present a multiplicity of radar reflective surfaces which in use of the life vest are oriented in a multiplicity of different planes which extend in a number of different directions. Suitably, the outer casing of the life jacket (10) should be comprised of a fabric which is transparent to radio waves used in radar so as not to impede the effectiveness of the radar reflective surfaces. The life jacket (10) may also include a radar resonating reflection wire (not shown) which is centrally located on the inside of the life jacket, to enhance the overall radar reflective effectiveness of the life jacket (10).

Figure 2 illustrates an alternative form of the invention being an inherently buoyant float 30. The float 30 has a relatively rigid plastic casing 32. The casing 32 may be provided in two halves and sealed by way of a flange 34 about the periphery of each half of the casing 32. The interior of the casing includes polystyrene foam 36. Dispersed throughout the polystyrene foam 36 are aluminium shavings 38.

Figure 3 illustrates a sheet of radar reflective material 40 which may be incorporated into inflatable buoyancy devices such as an inflatable life raft (not shown). The radar reflected material 40 has an array of short slits 42. The slits 42 enable the sheet 40 to be extended in the general plane of the sheet to produce the lattice configuration illustrated in Figure 3(b). Such sheets 40 may be incorporated internally in inflatable buoyancy devices whereby they are in the unexpanded configuration shown in Figure 3 a when the buoyancy device is uninflated. Upon inflation of the buoyancy device the sheets 40 may then extend in the manner illustrated in Figure 2. A large number of such sheets arranged internally will provide a reasonably large combined reflective surface in comparison with the size of the buoyancy device. The foregoing describes only one embodiment of the present invention and modifications can be made thereto without departing from the scope of the present invention.

Claims

CLAIMS:

1. A buoyancy device having an external surface and a plurality of radar reflective surfaces provided internally of the external surface.

2. The buoyancy device as claimed in claim 1 wherein the buoyancy device is inflatable and the external surface defines a three-dimensional body upon inflation.

3. The buoyancy device as claimed in claim 1 wherein the buoyancy device is inherently buoyant and the external periphery defines a three-dimensional body.

4. The buoyancy device as claimed in claim 2 or claim 3 wherein the plurality of radar reflective surfaces are distributed in an ordered arrangement in the body.

5. The buoyancy device as claimed in claim 4 wherein the plurality of radar reflective surfaces are arranged in an array or a three-dimensional lattice arrangement.

6. The buoyancy device as claimed in claim 4 or claim 5 wherein the plurality of radar reflective surfaces are distributed throughout the body.

7. The buoyancy device as claimed in claim 2 or claim 3 wherein the plurality of radar reflective surfaces are distributed in a random arrangement in the body.

8. The buoyancy device as claimed in claim 7 wherein the plurality of radar reflective surfaces are concentrated in the uppermost parts of the buoyancy device relative to the buoyant orientation of the device.

9. The buoyancy device as claimed in any one of the preceding claims wherein plurality of radar reflective surfaces are oriented in a plurality of different planes.

10. The buoyancy device as claimed in any one of the preceding claims wherein the plurality of radar reflective surfaces are defined by reflective particles.

11. The buoyancy device as claimed in claim 10 further including solid buoyancy material wherein the plurality of radar reflective surfaces are held in suspension in the solid buoyancy material.

12. The buoyancy device as claimed in claim 11 or claim 12 wherein the plurality of radar reflective surfaces include metal shavings dispersed in expanded polystyrene.

13. The buoyancy device as claimed in any one of the preceding claims wherein the plurality of radar reflective surfaces are defined by sheets or strips of radar reflective material.

14. The buoyancy device as claimed in claim 13 wherein the sheets or strips are arranged such that they are expandable from a collapsed configuration into an expanded configuration.

15. The buoyancy device as claimed in claim 13 or claim 14 wherein the sheets or strips are arranged as baffles or partitions extending internally of the body.

16. The buoyancy device as claimed in any one of claims 13 to 15 wherein the sheets or strips are arranged as longitudinal baffles and web portions extending between adjacent baffles.

17. The buoyancy device as claimed in claim 14 wherein the radar reflective material includes a plurality of sheets, adjacent ones of which are connected to each other to form an assembly which is expandable from a collapsed configuration into an expanded configuration with adjacent sheets lying next to each other in the collapsed configuration.

18. The buoyancy device as claimed in any one of the preceding claims wherein the buoyancy device comprises a float.

19. The buoyancy device as claimed in any one of the preceding claims wherein the buoyancy device comprises a boat fender.

20. The buoyancy device as claimed in any one of claims 1 to 17 wherein the buoyancy device comprises a one-man water craft.

21. The buoyancy device as claimed in any one of claims 1 to 17 wherein the buoyancy device comprises a small water craft.

22. The buoyancy device as claimed in any one of claims 1 to 17 wherein the buoyancy device comprises a life saving device.

23. The buoyancy device as claimed in claim 22 wherein the buoyancy device comprises a life vest.

24. A life vest incorporating radar reflective material.

25. A buoyancy device substantially as hereinbefore described with reference to the accompanying figures.

26. A life vest substantially as hereinbefore described with reference to the accompanying figures.