GB2171962A

GB2171962A - Inflatable lifejacket

Info

Publication number: GB2171962A
Application number: GB08605456A
Authority: GB
Inventors: David Vernon Edwards
Original assignee: RFD Ltd
Current assignee: RFD Ltd
Priority date: 1985-03-06
Filing date: 1986-03-05
Publication date: 1986-09-10
Also published as: GB8605456D0; GB2171962B; DK101086D0; FR2578508A1; DE3607126C2; DK101086A; US4685890A; DE3607126A1

Description

1 GB 2 171 962 A 1

SPECIFICATION

Inflatable lifejacket The present invention relates to inflatable lifejackets 70 and is particularly although not exclusively con cerned with inflatable lifejackets for installing in passenger aircraft.

Airline safety regulations require the provision in a passenger aircraft of a lifejacketfor each passenger and each member of the crew, which can be used in an emergency when an aircraft is forced to land in water. In such emergencies no time is available for giving last minute instruction to passengers in regard to the use of the lifejacket and the lifejacket therefore requires to be of a design which will rule out as far as is possible incorrect use of it by a passenger in an emergency. In particular, the life jacket requires to be so constructed that it is reversible, that is to say, that it can be donned by a passenger so as to overlie the chest either way round, with all the facilities on it being equally accessible and duplicated where necessary to achieve this end. At the same time, a lifejacket for use on passenger airlines should be made as lightweight as possible to reduce the weight penalty arising from the large number required for each aircraft and consideration of this requirement needs to be taken into account in the design of an acceptable lifejacket.

Lifejackets hitherto proposed have included an inflatable buoyancy envelope and an inflation unit for supplying gas to the envelope from a small storage cylinder under the control of an actuating device operated by the wearer. In an emergency landing on water, airline passengers are instructed to inflate their lifejackets after leaving the aircraft and the action required of the passenger to inflate the lifejacket must be a simple and natural one to take. It has long been considered that pulling on a cord to initiate inflation of the lifejacket best fulfils this requirement.

In a lifejacket in common use the inflation unit for supplying inflation gas to the buoyancy envelope is mounted on the outside of the envelope. It compris, 110 es a storage cylinder formed with a neck sealed by a metal closure diaphragm sufficient to withstand the pressure of the gas within the cylinder but at the same time capable of being pierced. A piercing device is provided for piercing the diaphragm and comprises a body portion into which the neck of the cylinder is screwed and an operating arm which is mounted on the body portion and which when actuated causes a piercing element to pierce the closure diaphragm. Inflation gas released from the cylinder upon actuation of the piercing device passes through the body portion of the device and into the envelope through an inlet tube which is secured in the wall of the envelope and which serves to provide support for the device and the cylinder. The operating arm is arranged to be actuated by the wearer of the jacket by pulling on a tab depending from the arm. While this arrangement has the advantage that a pulling action results in inflation of the envelope, it has the disadvantage that the inlet tube needs to pass through an opening in the envelope and to be sealed therein by welding. In another form of lifejacket hitherto proposed, the inflation unit is housed entirely within the inflatable buoyancy envelope and comprises a storage cylinder which stores inflation gas under high pressure and which is openable by an operating arm which extends alongside the cylinder and which when pressed toward the cylinder is operative to release gas from the cylinder into the envelope. The inflation unit is housed in a location pocket formed within the envelope so that it is confined to a specific location within the envelope. The lifejacket is inflated by the wearer first locating the inflation unit by searching with his hand, then grasping the unit through the jacket and squeezing it so as to move the arm toward the cylinder. This action on the part of the wearer requires previous instruction as to the inflation procedure and is considered to be unsuitable for a lifejacket required in the special circumstances of an aircraft being forced to land on waterwhere the evacuation of the aircraft needs to be carried out at high speed and no time is available for last minute instruction as to procedure. Furthermore, an addi- tional pocket needs to be provided on the inside of the lifejacket envelope to locate the inflation unit.

It is an object of the present invention to provide an inflatable lifejacket which does not suffer from the disadvantages of the hitherto proposed lifejackets, which is economical to manufacture and which is particularly suitable for use in passenger aircraft.

According to the present invention, there is provided an inflatable lifejacket for providing buoyancy in water to a wearer of the lifejacket, comprising an inflatable buoyancy envelope and inflation means mounted within the envelopefor inflation thereof, the inflation means comprising an inflation unit having a storage cylinder which stores inflation gas and which is openable by an operating arm which in an inoperative disposition extends alongside the cylinder in spaced relation thereto and which when pulled away f rorn the cylinder in an operating stroke is operative to release gas from the cylinder and the envelope including a projecting tongue portion which receives the arm and which is so positioned in relation to an adjacent support portion of the envelope that, when the unit is assembled in a mounted disposition in the envelope with the arm located in the tongue portion, the cylinder is aligned with the adjacent support portion and is supported thereby when the arm is pulled to release gas from the cylinder.

In accordance with the embodiment of the invention hereinafter to be described, the envelope in- cludes first and second sheet portions of a flexible material which overlie each other and which are joined together at their edges to form an envelope outer edge and the tongue portion and the adjacent support portion of the envelope are formed at the envelope outer edge. Preferably, the tongue portion of the envelope is so shaped and dimensioned that with the inflation unit in the mounted disposition in the envelope the tongue portion resists withdrawal of the arm therefrom. It is sometimes necessary to meet a requirement by an authority to provide a dual 2 GB 2 171 962 A - 2 1 buoyancy chamber lifejacket in which two buoyancy envelopes are formed, each with its inflation unit. In useithe wearer actuates both inflation units for inflation of the two envelopes, which together provide the required buoyancy for the jacket. In the event that one of the envelopes is damaged or its inflation unit fails, inflation of the other envelope maintains the wearer adequately supported with his head above water. Topping up of the inflated envelope by means of an oral inflation tube may then be carried out to bring the lifejacketto the required buoyancy.

A lifejacket according to the present invention may readily be constructed to provide this dual inflation facility and in accordance with a preferred embodiment of the invention hereinafterto be described a further envelope is provided which overlies the first-mentioned envelope to form a dual inflation envelope assembly, together with a further inflation unit identical to the first mentioned inflation unitfor inflation of thefurther envelope. The further envelope then includes a tongue portion which receives the operating arm of the further inflation unit and which is so positioned in relation to an adjacent support portion of the further envelope that, when the further unit as assembled in a mounted disposition in the further envelope with the arm located in the tongue portion, the cylinder of the further unit is aligned with the adjacent support portion and is supported thereby when the arm of the further unit is pulled to release gas from the cylinder of the further unit. Preferably, the further envelope is formed by a third sheet portion of a flexible material which overlies the second sheet portion of the first-mentioned envelope and which is joined at its edges to the edges of the second sheet portion to form an outer edge of the further envelope and the tongue portion of the further envelope and the adjacent support portion are formed at the outer edge of the further envelope.

In accordance with the embodiments of the invention hereinafter to be described, the lifejacket is of a form which is donned by a wearerwho passes his head through an opening in the lifejacletto bring a main body portion of the lifejacket to overlie the chest with a neck portion passing round the sides and back of the neck and resting on the shoulders. The lifejacket may comprise an outer cover within which the envelope or envelope assembly is remov- ably fitted or the envelope or envelope assembly itself may form the lifejacket.

Inflation units in common use for supplying gas for inflation of an inflatable lifejacket utilise a storage cylinderfor storing just sufficient gas under high pressure for fully inflating a buoyancy chamber of the lifejacket. The storage cylinder employed is provided with a metal closure diaphragm sufficient to withstand the pressure of the gaswithin the cylinder but atthe same time capable of being pierced. A piercing device is provided for piercing the diaphragm and comprises a support portion into which the cylinder is screwed and an operating arm which is mounted on the body portion and which when actuated causes a piercing elemeritto pierce the closure diaphragm.

It has long been appreciated that where the piercing element remains within the opening it has produced in the diaphragm, the element needs to be so constructed as to allow the escape of gas from the cylinder.Numerous proposals have been made for achieving this end. For example, the piercing element may take the form of a solid pin with a circumferential groove at a location such that when the pin is at the end of its piercing stroke the groove provides a passage at the opening in the diaphragm for the escape of gas from the cylinder. In another proposal the piercing element is a hollow piercing pin through which gas from the cylinder escapes. In yet another arrangement, the piercing element is formed with an enlarged head, portion and a shank portion of smaller cross section than the head portion so that when the element is at the end of its piercing stroke gas from the cylinder can escape through the annular space between the opening formed in the diaphragm and the shank portion of the element. Such proposals however require a piercing element of complex construction and the inflation unit is costly to manufacture.

A piercing device of less complex construction as proposed in prior British Specification No. 1060094 comprises a pivotally mounted operating arm which extends firstly over the end of the cylinderclosed by the diaphragm and then downwardly from the neck alongside the cylinder. A piercing element is pro- vided on the operating arm in the region where the arm passes overthe end of the cylinder and the construction of the device is such that when the operator grasps the unit in his hand and squeezes it so thatthe arm is moved toward the cylinderthe pivotal movement of the arm causes the piercing element to pierce the closure diaphragm on the end of the cylinder. The construction of the piercing device has howeverthe disadvantage that the opening produced in the diaphragm by the piercing element is completely filled by the element while the arm is maintained in the operating disposition. As.a result, very rapid inflation of a lifejacket may not be achieved in circumstances where the wearer of the lifejacket maintains his grasp on the operating arm.

With the object of overcoming the drawbacks of the above-mentioned prior proposals, the inflation unit in accordance with a preferred embodiment of the invention includes a piercing device for piercing a closure element on the storage cylinder to effect release of gas from the cylinder, the piercing device comprising an attachment portion which is attached to the cylinder and a piercing element which is caused in response to movement of the operating arm through its operating stroke to move in relation to the attachment portion between an inoperative disposition in which thepiercing element is clear of the closure element and a piercing disposition in which it pierces the closure element in a piercing stroke in which it moves downwardly into and across the closure element to produce an opening which is larger than that taken up by the piercing element in the piercing disposition.

In the preferred embodiment of the invention herinafter to be described, the operating arm of the inflation unit is pivotally mounted atone end on the 3 GB 2 171 962 A 3 attachment portion and extends at its other end alongside the cylinder, and the piercing element is mounted on the operating arm.

Embodiment of the invention will now be de- scribed by way of example with reference to the accompanying drawings in which:- Figure 1 is a front elevation of a lifejacket according to a first embodiment of the invention; Figure 2 is a front elevation of a dual buoyancy envelope forming part of the lifejacket shown in Figure 1; - Figure3 is a frontelevation of part of the lifejacket shown in Figure 1, drawn to an enlarged scale and with part of the lifejacket cut away; Figure 4 is a schematic section on the live IV-1V in Figure 3; Figure 5 is a schematic section of the lifejacket shown in Figure 1, taken on the line V-V in Figure 3, and drawn to an enlarged scale; Figure 6 is a section of the lifejacket shown in Figure 1 taken on the line VI-V1 in Figure 11; Figure 7 is a side elevation of a pressurised-gas inflation unit for use in inflating the inflatable lifejacket shown-in Figure 1; and Figure 8 is an end elevation of the unit shown in Figure 7.

Referring first to Figure 1, the lifejacket shown is of a type which is donned by a wearer who passes his head through an opening 11, bringing a main body portion 12 of the lifejacket to overlie the chest with a neck portion 13 passing round the sides and back of the neck and resting on the shoulders and who then secures the jacket in place by extending and passing tapes 14 and 15 first round his back at waist level and then bringing the ends to the front where he securely 100 ties them together. The lifejacket has accessories, such as those conventionally provided, including a topping up tube 16 which can be brought to the mouth of the wearer for oral topping up of the lifejacket, and identical further topping up tube (not shown) provided on the other side of the lifejacket for use if the lifejacket is donned the other way round, and a lamp 17 mounted at the edge of the lifejacket on a strap 18 and supplied from a battery 19 also secured to the edge of the lifejacket by a strap 20 which also holds a whistle 9 additionally held captive by a cord (not shown).

The lifejacket shown in Figure 1 includes an inner inflatable double envelope of the form shown in Figure 2. The double envelope, which is not seen in Figure 1, but which is indicated by the reference numeral 21 in the other figures, serves to inflate the main body portion 12, the neck portion 13 and a collar 26. The envelope 21 is formed from three air impermeable sheets of a plastics material which overlie each other and which are joined together along their edges by welding in a single hit operation to form an envelope outer edge 22 having the contour shown in Figure 2. The envelope 21 is left unsealed in a region 23 which allows for insertion of inflation units during assembly of the jacket and which is subsequently sealed in a separate single welding operation. As will be seen from Figure 2, the outer edge 22 of the envelope 21 is contoured to form two tongue.portions 24 and 25 located at the base of the envelope. As best seen in Figure 4 the three sheets forming the envelope 21 comprise a front sheet 27, an intermediate sheet 28 and a back sheet 29 which are joined together at their edges to form the envelope outer edge 22. As best seen in Figure 3 two inflation units 30 and 30' are provided. The units are of identical construction each comprising a cylinder 31,31' containing gas under high pressure and an operating arm 32,32' pivotally mounted on the head of the cylinder 31,3Vand operative to release gas from the cylinder by perforation of a closure diaphragm upon movement of the arm 32,32'away from the cylinder 31,3V.

Referring now to Figures 2,3 and 4, the inflation units 30,30'are assembled in the envelope 21 in the positions shown in Figure 3 by inserting the unit 30 between the sheets 28 and 29 in the unsealed region 23 of the envelope and manipulating the unit into a position in which the arm 32 is located within the tongue portion 24 of the envelope, with the cylinder 31 aligned with the adjacent portion 33 of the sealed edge 22. The unit 30' is then inserted between the sheets 27 and 28 in the unsealed region 23 of the envelope and manipulated to a position in which the arm 32' is located within the tongue portion 25 of the envelope with the cylinder 31' aligned with the adjacent edge portion 33' of the sealed edge 22. With the two units 30 and 30' so assembled, the region 23 is sealed by welding to form the double envelope 21, with a front inflatable compartment 34 housing the inflation unit 30' and a rear inflatable compartment 35 housing the inflation unit 30. Additionally, the topping up tubes 16 are mounted in the front and back sheets 27 and 29 in conventional manner. The sealed envelope 21 with its assembled inflation units 30 and 30' is then assembled within an outer cover of the lifejacket.

Referring again to Figure 3 the outer cover of the lifejacket is formed by front and rear fabric sheets 36 and 37 which are sewn together at their edges, except in the lower region of the jacket, where the rear sheet 37 is formed with a depending flap portion 39. An internal flap 40 of the same fabric as the sheets 36 and 37 is secured by sewing to the rear sheet 37 along the outer side edges of the sheet 37 and along a seam line 41 which extends across the lifejacket but is interrupted on each side to provide passageways 42 and 42' between the rear sheet 37 and the flap 40. As will be seen, the flap 40 extends upwardly between the sheets 36 and 37 and downwardly so as to be co- terminus with the flap portion 39 of the rear sheet 37. The edges of the sheets 36 and 37 are for the most part protected by an edge tape 38.

The sealed double envelope 21 with its inflation units 30 and 30' assembled as described is introduced into the lifejacket outer cover by passing it through the opening between the front sheet 36 and the flap 40. The lower end of the envelope is then placed behind the flap 40 and the tongue portions 24 and 25 carrying the operating arms 32 and 32' are passed through the passageways 42 and 42' so that they take up the dispositions shown in Figure 3. The two tongue portions 24 and 25 together with the operating arms 32 and 32' lie between the lower 4 GB 2 171 962 A 4 extension of the flap 40 and the flap portion 39 of the sheet 37. Pull cords 43 and 43' are tied at their upper ends to the arms 32 and 32' in regions where the arms are notched to provide secure attachment of the cords and are provided with pull tabs 44 and 44' at their lower ends.

As best seen in Figure 1,the front sheet 36 of the outer cover is cut away to form the opening 11 and provides an edge 45 to which the front edge of the collar 26 is sewn. Likewise thd rear sheet 37 is cut away for the opening 11 and provides an edge to which the rear of the collar is sewn. While it is intended that the collar inflates with the rest of the lifejacket, it has been found necessaryto restrictthe degree of inflation atthe front of the neck, whilst at the same time providing an inflatable support for the chin of the wearer. To provide for such inflation the edge 45 of the sheet 36 in the region of the chin of the wearer is, as best seen in Figure 6, connected by an inextensible bridge portion 46 to the corresponding edge of the rear sheet 37, thereby limiting the amount by which the lifejacket distends in this region. It is however necessary to provide for limited inflation of the collar 26 in the chin region.

As will be seen from Figure 2, the upper end of the envelope 21 is contoured to form two neck exten sions 47 and 47' partially enclosing a balloon portion 48. Upon assembly of the envelope 21 within the jacket cover the neck extensions 47 and 47' are pushed into the neck regions 13 of the jacket cover and connected together by snap fasteners 49,49'.

The bridge portion 46 bridging the sheets 36 and 37 in the region of the front of the neck is formed with a central opening 50 and the balloon portion 48 of the envelope 21 is pushed through the opening to 100 provide for inflation of the collar 26 in the chin region. In this way, the envelope 21, which can be produced by simple welding operations, provides for inflation of the neck region 13 of the lifejacket as well as for controlled inflation of the collar 26 in the chin region.

- As will be seen from Figure 3, the flap 40 is provided with a velcro pad 51 which, following assembly of the envelope 21 within the outer covers 36 and 37, is brought into contact with a correspond- 110 ing velcro pad provided on the front outer sheet 36. Furthermore, a velcro pad 52 provided on the flap portion 39 mates with a corresponding pad on the depending end of the flap 40 so that the two are held together, with the two cords 43 and 43' passing 115 through openings on either side of the pad 52.

In use, the wearer dons the lifejacket as hereinbefore described. At an appropriate time, he then proceeds to inflate it by pulling down hard on the tabs 44 and 44'. When the tab 44 is pulled, the operating arm 32 is pivoted downwardly away from the cylinder 31. which is held by the adjacent portion of the edge 22 of the envelope and by the stitching along the seam line 41.joining the flap 40 to the rear outer cover sheet 37. In a preferred form of inflation un it as hereinafter to be described with reference to Figures 7 and 8 pivoting of the arm 32 results first in shearing of a shear pin and then piercing of a closure diaphragm on the cylinder31, whereupon gas under high pressure is released from the cylinder 31 to fill the envelope compartment 35. In the same manner, when the other tab 44' is pulled gas from the - cylinder 31' is released to fill the envelope compart-_ ment 34. If, say, the inflation unit 30 fails to operate or if the rear inflation compartment 35 is ruptured and loses inflation the intermediate sheet 28 of the envelope 21 is pushed by the inflation gas in the compartment 34 into contact with the front sheet 27. The wearer of the jacket is nevertheless adequately supported - in the water as inflation of either of the compartments 34 and 35 is arranged to be sufficient to support a wearer of the lifejacket with his head above water. Subsequent topping up of the compart ment 34 by means of the oral inflation tube will,then completely fill out the lifejacket to its designed shape and provide the required additional buoyancy.

It will be apparent that in the lifejacket hereinbefore described with reference to the drawings the inner envelope,21- is of simple form and comprises simply three sheets of a plastics material welded together by simple single hit welding operations. the contour of the envelope provides the tongue portions 24 and 25 which serve to locate the inflation units 30 and 3or within the envelope and the arrangement of the assembled inflation, units within the envelope facilitates operation of them by pulling on the arms 32 and 32' using the tabs 44 and 44.

An inflation unit now to be described with reference to Figures 7 and 8 is particularl y suitable for use in the inflation of the lifejacket hereinbefore described with reference to Figures 1 to 6.

Referring now to Figures 7 and 8, an inflation unit 100 is shown which includes a storage cylinder 101 containing an inflation gas, such as carbon dioxide, under high pressure. The cylinder 101 is formed with an externally screw-threaded neck 102, the end of which is closed by a-metal closure diaphragm 103. A piercing device 104 is provided for piercing the diaphragm 103 to effect release of gas from the container 101. The device 104 includes a body portion 105 formed with a screw-threaded.axial bore 106 into which is screwed the neck 102 of the cylinder 101. The body portion 105 is formed with shoulders 107 and 108 and an operating arm 109 is pivotally mounted. between the shoulders 107 and 108 on a pivot pin 110 supported by the shoulders 107 and 108 and passing through a head portion 111 of the operating arm 109. The head portion 11 - 1 is formed with an inclined face 112 in which is mounted a piercing element 113. The operating arm 109 extends from the head portion 111 firstly away from the body portion 105 and then alongside the cylinder 1 01--as shown. A shearpin 115 supported bV the shoulders 107 and 108 passes through the head portion 111 of theoperating arm 109 to hold it in the position shown in Figure 7.

Itwill be seen from Figure 7 thatwith the operatinj arm 109 in the position shown, the piercing element 113 is in proximity to but spaced from the closure diaphragm 103. The operating arm 109 is held in thi, position bythe shear pin 115 which prevents inadvertent operation. To effect release of gas from the cylinder 101 the arm 109 is pulled away from thE cylinder 101 to shear the pin 115 and cause the heac 111 to pivot on the pivot pin 110 from the inoperativ GB 2 171 962 A 5 position shown in Figure 7 to a position in which the end of the face 112 of the head 111 bears on an end face 116 of the body portion 105. During this movement of the head 111, the piercing element 113 moves through a piercing stroke, determined by its disposition in relation to the pivot pin 110, in which it moves into and across the diaphragm 103 producing an opening in the diaphragm 103 which is larger than that taken up by the piercing element 113 at the end of its piercing stroke. The gas under pressure in the cylinder 101 is thereby rapidly released through the opening cut by the piercing element 113 without the need for withdrawing it from the opening by returning the operating arm 109 to the position shown in Figure 7.

In the embodiment of the invention hereinbefore described with reference to the drawings the envelope 21 is housed within an outer cover formed by cover sheets 36 and 37, collar 26 and flap 40. It will however be appreciated that for some purposes the envelope 21 may itself form the lifejacket and no provision made for an outer cover. In this event, depending flaps may be formed on the envelope to shield the projecting tongue portions 24 and 25 and the operating arms 32 and 32' located within them.

Claims

1. An inflatable lifejacket for providing buoyancy in water to a wearer of the lifejacket, comprising an inflatable buoyancy envelope and inflation means mounted within the envelope for inflation thereof, the inflation means comprising an inflation unit having a storage cylinder which stores inflation gas and which is openable by an operating arm which in an inoperative disposition extends alongside the cylinder in spaced relation thereto and which when pulled away from the cylinder in an operating stroke is operative to release gas from the cylinder and the envelope including a projecting tongue portion which receives the arm and which is so positioned in relation to an adjacent support portion of the envelope that, when the unit is assembled in a mounted disposition in the envelope with the arm located in the tongue portion, the cylinder is aligned with the adjacent support portion and is supported thereby when the arm is pulled to release gas from the cylinder.

2. A lifejacket according to claim 1, wherein the envelope includes first and second sheet portions of a flexible material which overlie each other and which are joined together at their edges to form an envelope outer edge and wherein the tongue portion and the adjacent support portion of the envelope are formed at the envelope outer edge.

3. A lifejacket according to clairii 2, wherein the tongue portion of the envelope is so shaped and dimensioned that the inflation unit in the mounted disposition in the envelope the tongue portion resists withdrawal of the arm therefrom.

4. A lifejacket according to claim 2 or 3, wherein the lifejacket is provided with a further envelope which overlies the first-mentioned envelope to form a dual inflation envelope assembly and a further inflation unit identical to the first mentioned inflation 130 unit for inflation of the further envelope and wherein - the further envelope includes a tongue portion which receives the operating arm of the further inflation unit and which is so positioned in relation to an adjacent support portion of the further envelope that, when the further unit is assembled in a mounted disposition in the further envelope with the arm located in the tongue portion, the cylinder of the further unit is aligned with the adjacent support portion and is supported thereby when the arm of the further unit is pulled to release gas from the cylinder of the further unit.

5. A lifejacket according to claim 4, wherein the further envelope is formed by a third sheet portion of a flexible material which overlies the second sheet portion of the first- mentioned envelope and which is joined at its edges to the edges of the second sheet portion to form an outer edge of the further envelope and wherein the tongue portion of the further envelope and the adjacent support portion are formed at the outer edge of the further envelope.

6. A lifejacket according to claim 2,3 or4, wherein the envelope outer edge is contoured to form the or each tongue portion.

7. A lifejacket according to any of claims 1 to 6, wherein the lifejacket comprises an outer cover within which the envelope or envelope assembly is removably fitted.

8. A lifejacket according to claim 7, wherein the lifejacket is of a form which is donned by a wearer who passes his head through an opening in the lifejacket to bring a main body portion of the lifejacketto overlie the chest with a neck portion passing round the sides and back of the neck and resting on the shoulders, and wherein the envelope or envelopeassembly is contoured to provide inflation of the main body portion and the neck portion of the outer cover.

9. A lifejacket according to claim 8, wherein the outer cover is contoured to form the opening and to define the body portion and the neck portion of the lifejacket.and wherein the envelope or envelope assembly is contoured to form a body portion and two neck extension swhich define an opening cor- responding to the opening in the outer cover and wherein the two neck extensions are inserted into the neck portion of the outer cover and their ends connected together to provide for inflation of the neck portion of the outer cover.

10. A lifejacket: according to claim 9, wherein the envelope or envelope assembly is contoured to provide within the outer cover in the region of the front of the neck of the wearer of the lifejacket a balloon portion which upon inflation of the lifejacket provides support for the chin for the wearer.

11. A lifejacket according to claim 10, wherein the outer cover of the lifejacket is formed with a distensible collar portion at the opening and an inextensible bridge portion in the region of the chin of the wearer to limit the amount by which the collar portion distends in the chin region, and wherein the bridge portion is formed with an opening through which the balloon portion is passed for location within the collar portion of the outer cover in the region of the chin of the wearer.

6 GB 2 171 962 A 6

12. A lifejacket according to any of claims 1 to 6, wherein the envelope or envelope assembly forms the lifejacket and is donned by a wearer who passes his head through an opening in the envelope or envelope assembly to bring a main body portion of the envelope to overlie the chest with a neck portion passing round the sides and back of the neck and resting on the shoulders.

13. A lifejacket according to any of claims 8 to 12 wherein the or each tongue portion is located at the base of the body portion of the or each envelope.

14. A lifejacket according to any of claims 1 to 13, wherein the contour of the envelope or envelope assembly is substantially as illustrated in Figure 2 of the accompanying drawings.

15. A lifejacket according to any of claims 1 to 14, wherein the sheet portions of the envelope or envelope assembly are of a plastics material welded together along the envelope or envelope assembly outer edge.

16. A lifejacket according to any of claims 1 to 15, wherein the or each inflation unit includes a piercing device for piercing a closure element on the storage cylinder to effect release of gas from the cylinder,the piercing device comprising an attachment portion which is attached to the cylinder and a piercing element which is caused in response to movement of the operating arm through its operating stroke to move in relation to the attachment portion between an inoperative disposition in which the piercing element is clear of the closure element and a piercing disposition in which it pierces the closure element in a piercing stroke in which it moves downwardly into and across the closure element to produce an opening which is larger than thattaken up by the piercing element in the piercing disposition.

17. A lifejacket according to claim 16, wherein the operating arm is pivotally mounted at one end on the attachment portion and extend at its other end alongside the cylinder, and wherein the piercing element is mounted on the operating arm.

18. An inflatable lifejacket substantially as hereinbefore described with reference to Figures 1 to 6 of the accompanying drawings.

19. An inflatable lifejacket according to claim 1 wherein the inflation unit is substantially as hereinbefore described with reference to Figures 7 and 8 of the accompanying drawings.

20. A inflatable lifejacket substantially as hereinbefore described with reference to Figure 9 of the accompanying drawings.

Printed in the UKfor HMSO, D8818935,7186,7102. Published by The Patent Office,25 Southampton Buildings, London, WC2A lAY, from which copies maybe obtamed.