GB2197627A

GB2197627A - Life jacket

Info

Publication number: GB2197627A
Application number: GB08725209A
Authority: GB
Inventors: David John Parker; Angela Margaret Parker; Martin John Parker
Original assignee: A P VALVES
Current assignee: A P VALVES
Priority date: 1986-11-22
Filing date: 1987-10-28
Publication date: 1988-05-25
Anticipated expiration: 2007-10-28
Also published as: GB2197627A8; GB8627991D0; GB2197627B; GB8725209D0

Abstract

A life jacket (11) has at least one buoyant chamber (12, 13) defined at least in part by two opposite gas impermeable panels 29, 30 in which inflation pressure tending to deform the chamber out of the desired shape is resisted by a plurality of retainers (26) which "quilt" the panel, the retainers (26) passing through both of the opposite panels (29, 30) and acting to seal the openings in the panels (29, 30) through which they pass, or to reinforce a welded seal forming a bead (50). The retainers have large flanges to ensure that the forces exerted on the panel material are spread over a sufficiently wide area as not to cause rupturing stress. <IMAGE>

Description

AN IMPROVED LIFE JACKET The present invention relates to an improved life jacket.

Life jackets usable as buoyancy aids in an emergency normally have a shape based on a collar which fits around the neck of a wearer and includes an inflatable gas chamber positioned in the vicinity of the upper chest so that the wearer is maintained in a buoyant position face uppermost. Life jackets for other purposes are also known, particularly for divers where the life jacket also serves as a flotation chamber usable in obtaining a state of neutral buoyancy. Life jackets for divers are also formed on the basic collar-type configuration, but include side chambers rather than a chest chamber, the side chambers being linked by a retaining strap passing across the front of the wearer. The tubular collar-type configuration has been used in the past in order to obtain the maximum internal volume for the minimum external surface area.It will be appreciated that, upon inflation, any gas-impermeable chamber will tend to adopt a spherical configuration, or a configuration as nearly spherical as the shape of the panels will permit, in order to seek to maximise the internal volume for the given surface area in accordance with well known actual physical principles. This, however, has restricted the design since it has not been possible to produce a life jacket having relatively flat side or front panels over an extended area due to this tendency, upon inflation, to adopt a spherical or near spherical shape. This is particularly significant in the case of life jackets for divers in which the inflation is generally effected from the compressed air bottle carried by the diver so that the life jacket has to be able to resist very considerable internal forces..

Indeed, prior attempts to design life jackets having relatively flat panels as part of their design have incorporated transverse partitions welded across opposite major faces of the panel, but such welds have been found to fail in service, under the forces exerted upon inflation. It need hardly be stated that an essential and unavoidable requirement of life jackets is that they should be adequately robust to withstand very rigorous conditions and to have built in "redundancies" that is, a capability of withstanding stresses in excess of those normally expected in service, since considerable reliance is placed on their operation in times of emergency.

The present invention seeks to provide a life jacket construction which will give the designer greater freedom in determining the precise shape and configuration to be adopted by enabling relatively flat panels to be utilised, whilst resisting any tendency of the gas-impermeable chambers defined thereby to adopt a spherical or near-spherical configuration upon inflation.

According to the present invention, therefore, a life jacket having at least one buoyant chamber defined at least in part by two opposite gas-impermeable panels, in which inflation pressure tending to deform the chamber out of the desired shape is resisted by at least one retainer which passes through both of the said opposite panels and acts on the panels from the outside thereof, the retainer acting also to press together the rims of the openings in the panels through which it passes by contact therewith.

It will be appreciated that the present invention also comprehends a retainer for holding together two opposite wall panels of an inflatable chamber, such as on a life jacket, comprising two interfitting retainer parts adapted to pass through respective aligned openings in the opposite wall panels and to interengage one another, the retainer parts having enlarged heads shaped to press the panels together, when so interengaged, whereby to form an annular seal around the openings through which the parts pass.

The inner faces of the wall panels may be held together around the rims of the openings by the retainer, or may be held at a pre-determined spacing from one another by such retainer.

Conveniently, the retainer comprises two opposite interfitting parts which can be introduced into openings in the wall panels from the exterior thereof. In one embodiment a spacer member is provided through which the said two opposite interfitting retainer parts of the retainer may pass, such spacer acting to determine the minimum separation of the wall panels in the vicinity of the retainer. A suitable technique for engaging such a spacer upon assembly of a buoyant chamber comprises threading the spacer on a flexible line or cord passing through the openings, which cord can be drawn tight to align the spacer with the openings when it is desired to introduce the interfitting parts of the retainer therein.

The openings in the opposite wall panels may be sealed by a clamping force exerted between the opposite interfitting retainer parts or between the spacer and an associated retainer part.

Preferably, however, in order to obtain complete security against leakage, the opposite wall panels are sealed together by welding of the material thereof around the rim of the opening through which the retainer passes. This has the beneficial effect of creating an enlarged annular bead around the opening against which the retainer can engage more securely to hold the opposite wall panels of the life jacket together.

A first part of the retainer may have a screw threaded shank and a second part of the retainer a threaded opening engageable by the screw threaded shank to secure the two parts together.

Alternatively, however, the two parts of the retainer may be snap engageable together or may be welded together upon assembly.

At least one of the said interfitting parts of the retainer may have a boss which engages the rim of the opening in the panel through which the retainer projects for pressing the rim of the opening against a cooperating part of the retainer to effect sealing of the chamber at this opening.

The said one interfitting part of the retainer may further include a radial flange portion acting to relieve the pressure on the panel due to the sealing clamping action of the boss whereby to spread the sealing load over a wider area. This is an important consideration when it is understood that the inflation of the life jacket may be effected by utilising compressed gas from the breathable gas bottle carried by a diver, in which case the stresses exerted on the panels may be very considerable. By spreading the area at which the retainer acts the load at any one point on the fabric can be reduced to acceptable limits.

The material from which the life jacket is made will, in any event, by a very resistant material having a high tensile strength and resistance to tearing. Preferably, such wall panels are composed of two layers of gas-impermeable material, namely an inner resilient layer (for example, polyurethane) and an outer flexible abrasion-resistant layer (for example, woven nylon). The said inner layer may not be bonded or otherwise fixed to the outer layer except at the points where the retainers pass through both opposite panels defining a chamber.

Although preferable, such a construction is not essential, and the invention can be applied to a life jacket having all panels composed of a single layer of gas-impermeable abrasion-resistant material. The use of a separate inner gas-impermeable layer, however, adds to the safety and durability of the life jacket by making it possible for the inner layer to move away from the outer layer in the event of a rupturing force being exerted thereon, thereby increasing the possibility that abrasion or tearing of the outer cover will not lead immediately to the escape of gas from the life jacket, which would make it unserviceable.

One embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic perspective view of a life jacket incorporating the principles of the present invention; Figure 2 is a section taken through the life jacket of Figure 1 on the line II-II thereon; Figure 3 is a section similar to that of Figure 2, illustrating a further embodiment of the invention; and Figure 4 is a section through a prior art life jacket construction; and Figure 5 is a sectional view similar to that of Figure 2, illustrating a further embodiment of the invention.

Referring now to the drawings, the life jacket shown in Figure 1 is particularly adapted for use by a diver. It will be appreciated that life jackets for emergency use and/or other purposes such as for surface water sports including sailing, wind surfing and the like, may be constructed using the principles of the present invention and the specific description herein below with reference to a life jacket for a diver is provided without any loss of generality in the application of the invention.

Previous life jackets for divers have unavoidably incorporated a collar which passes around the neck of a wearer and includes two main tubular buoyancy chambers extending over the front portion of the shoulders and down to the sides of the wearer. Such a configuration, although it provides adequate buoyancy in an appropriately balancing configuration, that is one which does not apply an excessive buoyancy to the front or back of the diver leading to unwanted turning moments which have to be overcome in obtaining equilibrium in a selected orientation, do in fact present a certain degree of encumbrance to the diver obstructing or hindering free movement of the arms due to the presence of these tubular buoyancy chambers.The life jacket illustrated in Figure 1, and generally indicated with the reference numeral 11 overcomes this problem by providing two main lateral buoyancy chambers 12, 13 communicating with generally tubular buoyancy chambers 14,15 which are positioned behind the diver when the life jacket is fitted.

Indeed, the life jacket illustrated in Figure 1 also serves as a harness for mounting a gas bottle 15 (usually air) for which purpose the life jacket incorporates a main dorsal member 17 which forms a rigid base on which the fabric panels defining the chambers referred to above are held. Attached to this dorsal member 17, and to the buoyancy chambers are attachment straps 18,19 of a fixing harness, by which the life jacket can be fitted to a wearer.

Attached to the upper part of one of the tubular chambers 15, and in communication with the interior thereof, is a flexible tube 20 which carries at its free end a mouth piece 21 incorporating an emergency demand valve 21a by means of which it is possible for the diver to breath the air contained within the life jacket in an emergency, such as failure or exhaustion of the primary gas bottle 16 A tube 22 interconnects a gas bottle control valve 23 of the main gas bottle 15 with a manually controllable feed valve 24 which allows gas to be drawn from the gas bottle 16 and introduced into the tube 20, and therefore into the interior of the life jacket 11 to increase its buoyancy as desired.A release valve, controllable by a knob 25 allows the escape of gas from the life jacket so that, by means of these two controls, the diver's buoyancy can be adjusted by increasing or decreasing the amount of air inflating the life jacket.

The main lateral gas chambers 12, 13 have a rather elongate flattened configuration and are prevented from adopting a spherical or near spherical shape upon inflation by the use of retainers 26 which act to "quilt" the chambers 12, 13 retaining them in the desired approximately planar shape so that they do not restrict the arms of a wearer. It will be appreciated, moreover, that by providing forwardly projecting approximately planar chambers 12,13 the requirement for tubular chambers passing over the shoulders of the wearer can be avoided so that the upper arms of the wearer are left entirely free and unobstructed. The life jacket of the present invention is therefore able to perform its essential functions without adding to the encumbrance of the equipment necessarily carried by a diver.

Referring now to Figure 2, the configuration of the retainers 26 is illustrated in more detail. It will be appreciated, in this respect, that the life jacket illustrated is one in which each wall panel has a double-skin structure, namely, one incorporating an outer layer 27 of abrasion-resistant flexible gas-impermeable material such as woven nylon with a coating on its inner face rendering it entirely gas-impermeable, and an inner layer 28 which is not attached to the outer layer 27, and is composed, for example, of polyurethane having a thickness in the region of 400 p.

Two opposite panels 29,30 having the double-skin structure discussed above are shown, with the inner and outer layers of the panel 29 being identified with the reference numerals 28a,27a respectively. The panels are held together at an appropriate point by a retainer 26 which is formed in two parts, namely, a first part 10 having a threaded shank 31 and a mushroom head 32 with a generally dished radial flange 33, and a socket part 34 having a hollow threaded boss 35 and a dished flange 35 similar in shape to the flange 33 of the part 10.The length of the boss 35 is such that it presses the two panels 27,28 firmly against the underface of the mushroom head 32 when the threaded shank 31 is screwed tightly into the boss 35, and the radially outermost rims of the flanges 33,36 also press together the two opposite panels 29,30, whereby to spread the clamping load over the area of the mushroom heads. It will be appreciated that the holes formed in the panels 29,30 to receive the retainer 26 will be in the region of 3/8 in.

(0.93 cm) diameter, whereas the diameter of the flanges 33,36 are in the region of 3/4 in. (1.87 cm)to 1 in. (2.5 cm). The load exerted on the retainer 25 by the tension in the panels 29,30 when inflated is thus spread around the whole of the perimeter of the flanges 33,35 and thus constitutes a relatively low point loading well within the tear-resistant capabilities of the materials used.

In the embodiment of Figure 2 the opposite panels 29,30 are brought together in contact with one another by the retainer 26. This results in relatively deep hollows in the surface of the chambers 12,13. If it is desired to reduce the depth of these hollows the retainer 26 may be formed as in the embodiment of Figure 3 with a spacer 40 fitted between the panels 29,30, and to which the rims of the openings in the panels 29,30 through which the shank 31 of the retainer part 30 passes.

Turning now to Figure 4, a prior art structure will be briefly described. Here, opposite panels 41,42 are held approximately in shape by transverse webs or partitions 43,44 which are attached to the inside faces of the panels 41, 42 by welding at points 45,46,47 and 48. It will be appreciated that the forces exerted at such weld points upon inflation of the chamber is very considerable and, particularly when inflation is effected by means of a gas bottle such as the gas bottle 16 in the embodiment of Figure 1, can lead to rupture of the panels at the weld points.By contrast, the retainer 26 of the present invention, whether it draws the panels 29,30 directly together as in the embodiment of Figure 2, or spaced as in the embodiment of Figure 3, very strongly resists any tendency to tear the layers 29,30 of the panels and securely holds these in the required position. The very considerable strength of the retainer 26 as well as the fact that it exerts the retaining force effectively from the outside of the layers 29,30, ensures a safe, durable and reliable structure.

Finally, the embodiment of Figure 5 is similar to that of Figure 2, and the same reference numerals have been used to identify corresponding components. In this embodiment, however, the aperture in the inner layers 28,28a is welded together around its rim to form a bead 50 which is thicker than the combined thickness of the layers 28,28a. This creates an enlarged annular region around the opening over which the rims of the flanges 33,36 engage to provide complete security against mechanical separation. The security of the seal formed by welding the bead 50 is also increased by the mechanical reinforcement of the retainer flanges 33,36.

In this embodiment the boss 35 which, in the embodiment of Figure 2, pressed against the material within the retainer, is very much shorter and tapered so that it does not exert any substantial force on the panels 29,30 when the retainer 26 is secured over the bead 50.

Claims

1. A life jacket having at least one buoyant chamber defined at least in part by two opposite gas-impermeable panels, in which inflation pressure tending to deform the chamber out of the desired shape is resisted by at least one retainer which passes through both of the said opposite panels and acts on the panels from the outside thereof, the retainer acting also to press together the rims of the openings in the panels through which it passes by contact therewith.

2. A life jacket as claimed in Claim 1, in which the inner faces of the wall panels are held together around the rims of the openings though which the retainer passes.

3. A life jacket as claimed in Claim 2, in which the retainer comprises two opposite interfitting retainer parts which can be introduced into the openings from opposite sides of the panel.

4. A life jacket as claimed in any of Claims 1 to 3, in which the openings in the wall panels are sealed by a clamping force exerted between the opposite interfitting retainer parts or between a spacer and an associated retainer part.

5. A life jacket as claimed in Claim 3 or Claim 4, in which a first retainer part has a screw threaded shank and a second retainer part has a threaded opening engageable by the screw threaded shank to secure the two parts together.

6. A life jacket as claimed in any of Claims 3 to 5, in which at least one of the said interfitting parts of the retainer has a boss which engages the rim of the opening in the panel through which he other part projects, for pressing the rim of the opening against a face of the said other part to seal the two panels together around this opening.

7. A life jacket as claimed in any of Claims 3 to 6, in which the said two opposite interfitting parts of the retainer each have a radial flange portion so shaped as to cooperate to press the panels together around an annular region surrounding and spaced from the opening through which the retainer passes.

8. A life jacket as claimed in Claim 7, in which at least one of the said radial flanges is dished with a rim axially spaced from a central boss portion thereof for cooperation with the rim of the opposite retainer part to clamp an annular portion of the two wall panels between them.

9. A life jacket as claimed in Claim 8, in which both retainer parts have respective dished radial flanges.

10. A life jacket as claimed in any of Claims S to 9, in which the said boss has an axial length less than the distance between the central portions of the retainer parts when the opposite rims are in contact with one another.

11. A life jacket as claimed in any preceding Claim, in which the wall panels are composed of two layers at least one of which is made of gas-impermeable material, namely an inner resilient layer and an outer flexible abrasion resistant layer.

12. A life jacket as claimed in Claim 11, in which the said inner layer is not bonded or otherwise fixed to the outer layer except at the points where the retainers pass right through both oppposite panels defining a chamber.

13. A life jacket as claimed in Claim 11 or Claim 12, in which the outer layer is a woven fabric with an internal coating of gas-impermeable material.

14. A life jacket as claimed in any of Claims 11 to 13, in which the inner layer is a polyurethane film in the region of 400 r thick.

15. A life jacket as claimed in any of Claims 11 to 14 in which the inner layer is formed with an annular bead surrounding the opening against which the radial flanges of the two retainer parts engage.

15. A life jacket as claimed in Claim 15, in which the said annular bead is formed by welding the two inner layers together.

17. A life jacket as claimed in any of Claims 1 to 10, in which the wall panels are composed of a single layer of gas impermeable abrasion-resistant material.

18. A life jacket as claimed in any preceding Claim, in which the retainer parts are held together by welding.

19. A life jacket as claimed in any preceding Claim in which the retainer parts are snap-engageable together.

20. A life jacket substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

21. A retainer for holding together two opposite wall panels of an inflatable chamber, such as on a life jacket, comprising two interfitting retainer parts adapted to pass through respective aligned openings in the opposite wall panels and to interengage one another, the retainer parts having enlarged heads shaped to press the panels together, when so interengaged, whereby to form an annular seal around the openings through which the parts pass.