GB1593247A - Methods and apparatus for inflating inflatable structures - Google Patents

Description

(54) METHODS AND APPARATUS FOR INFLATING INFLATABLE STRUCTURES (71) I, PETER SEATON, of British Nationality, of 3, Trinity Street, Dorchester, Dorset, do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed to be particularly dewcribed in and by the following statement: This invention relates to inflatable structures, and in particular the present invention is concerned with the inflation and deflation of 'inflatable' boats or other structures which comprise as a major part of their construction one or more gas tight containers made of a flexible material which is able to contain gas at a pressure above atmosphere.

In the case of boats which are used as tenders or the like for yachts or other light craft it is usually highly desirable to be able to inflate the inflatable boats rapidly and without a great deal of difficulty.

In relation to the boats mentioned above it is the usual practice to form the boats from one or more tubular gas tight members of a suitable cross section. This cross section usually being round or oval. Such tubes are usually inflated by using a supply of compressed air, in view of the large amount of air necessary to achieve the required degree of inflation. However, such supplies of compressed air are not normally available to the yachtsman, particularly whilst his yacht is in use.

This is because such compressed air supplies involve the use of an air compressor unit which is not the type of unit likely to be sufficiently light in weight for carrying on board a yacht or relatively heavy bottles of the compressed air which are also not particularly for carrying on board a yacht. In view of the difficulties in relation to compressed air supplies it is the usual practice to pump-up the tubular members of an inflatible boat by means of a manually operable pump. Such pumps must be capable of supplying the final 'fully inflated' air pressure without undue difficulty. Furthermore, the effort involved in the pumping action must not be excessive. In view of such factors it follows that the volume of air delivered by a suitable pump is relatively small so that the inflation process is slow and tedious.

Furthermore, in practice, the connector arrangements provided for coupling the pump to the tubular elements to be inflated tend to be of a relatively small diameter so that the normally provided inlet valve offers resistance to escape of air during the deflation of the previously inflated elements.

Consequently the deflation operation is a slow process.

It is an object of the present invention to provide a method of and apparatus for inflating inflatable structures which avoids at least some of the difficulties mentioned above.

According to the present invention there is provided an air inflatable structure comprising a main body which is required to be air pressurised and which is collapsible or otherwise foldable from its inflated shape to a stowed configuration; an elongate tubular auxiliary body connected at one end to the main body, the auxiliary body being pressurisable by air and collapsible or otherwise foldable from an extended shape for the purposes of stowage or the like: an air flow path between the two bodies: an air inlet arrangement permitting admission of air into the structure; and means for driving air from the auxiliary body in a direction from the free end thereof, the arrangement being such that on displacing both said main and said auxiliary bodies from their collapsed or stowed condition respectively into their inflated form and elongated condition air is inducted into both said bodies, and such that on operating the air driving means so as to reduce the internal volume of the elongate auxiliary body in a direction from the free end thereof towards the end connecting with the main body the air inlet arrangement closes against air flow into the structure and following such closure further reduction of said internal volume produces a corresponding increase in the pressure within the main body.

Preferably, the structure includes valve means in said air flow path whereby air can be retained in the main body to allow further induction of air into the auxiliary thereby to enable further pressurisation of the main body by further driving of air from the auxiliary body.

Preferably, the volume of the inflated auxiliary body is reduced by winding or rolling the free end thereof onto a shaft or spindle, the arrangement being such that the pressure increase produced in the main body is related to the amount of the auxiliary body wound or rolled onto the shaft or spindle.

In a preferred construction the inflatable structure is in the form of a boat.

Conveneiently, the main body includes means for providing a self supporting facility during the inflation thereof, the arrangement being such as to enable the main body to assume its desired shape during the unfolding or expansion.

For a better understanding of the invention and to show how to carry the same into effect reference will now be made to the accompanying drawings in which Figure 1 is a schematic representation in longitudinal cross section of an inflatable elongate structure of simple tubular form and which incorporates features of the invention, the Figure illustrating the structure when inflated sufficiently to demonstrate the final shape of the structure, Figure 2 is a plan view of Figure 1, Figure 3 is a schematic representation in longitudinal cross section of the structure of Figures 1 and 2 when in a very early stage of the inflation process, Figure 4 is a plan view of Figure 3, Figure 5 is a view similar to that of Figure 1 but illustrating the structure when fully inflated Figure 6 is a plan view of Figure 5, Figure 7 is an elevation of a modified detail of the structure shown in the previous Figures, Figure 8 is a longitudinal section of the modified detail of Figure 7, Figure 9 is a longitudinal view of the detail of Figures 7 and 8, when in an operational setting corresponding to the fully inflated condition of the structure of the invention.

Figure 10 is sectional side view of a modification of a detail of the arrangements provided for pressurising the structures of the present invention, Figure 11 is a plan view of the arrangements of Figure 10, Figure 12 is a schematic plan view of a first construction of a boat incorporating features of the invention, Figure 13 is a schematic plan view of a second construction of a boat incorporating features of the invention Figure 14 is a schematic plan view of a pump construction utilising features of the invention.

Figure 15 is a transverse section of the arrangement of Figure 14, the section being taken on the line A-A of Figure 14.

Referring now to the drawings and more particularly to Figures 1 through 6. In Figures 1 and 2 an inflatable structure includes a main tubular body 1 formed from a flexible material such as a rubberised fabric or a fabric like material or plastics material which has a relatively low elasticity in the sense that it will form a 'tight' or drum-like wall when the body is subjected to an internal pressurisation. The tubular body 1 can be reinforced by a plurality of spaced hoops or rings formed of metal or a plastics material. Alternatively rubber or other elastomer rings could be used. In the Figures the rings include end rings 2 and 3 and intermediate rings 4, of which only one of the latter is shown. It will be understood that the total number of rings and the material from which the rings are made will be related to the load that the rings are required to support when in use.Furthermore, the rings can be other than circular according to the cross section of the body.

A second tubular body 5 is attached to the end 6 of the body 1, this body 5 being of a lesser diameter than that of the body 1. The other end 7 of the body 5 is attached to a spindle 8 in such manner that the end 7 is sealed against the spindle in an air tight manner, and such that the body 5 can be rolled onto the spindle.

The shaft or spindle 8 is suitably journalled in a frame or other means 9. The spindle is provided with a handle 10 which is either removable or foldable when not required for use.

An air inlet valve 11 is provided in the wall of the body 1, the valve being only very schematically indicated in the Figures. The valve 11 is such that it opens or can be readily opened to admit air into the interior of the body 1 if the pressure outside the body exceeds that inside the body and such that it automatically closes or is otherwise closed when the air pressure is in the vicinity of atmospheric pressure.

The other end of the body 1 is closed by a cap or the like 12 which is preferably integral with the body 1 and of the same material as the body.

Figures 1 and 2 depict the structure in its opened or 'full shape' condition after it has been initially filled with air but before it has been pressurised to a pressure above atmospheric pressure.

When the structure is in its deflated condi tion for the purposes of stowage or the like the material of the body 1 is readily foldable into a relatively small volume and in fact the mode of folding is normally chosen so as to reduce the folded volume as much as possible.

One convenient way of folding the body and at the same time assist in driving out air from the body is to push the rings 2, 3 and 4 towards each other. Similarly the secondary or auxiliary body 5 is rolled-up or otherwise reduced in volume. The body 5 need not be of the same cross section as the body 1 and can thus have any cross section thought desirable. Furthermore, the material of the body 5 can differ from that of the body 1.

The inflation of the structure as so far described will now be considered. The free end of the body 5 is anchored by means of the support structure for the spindle 8 or by any other convenient means. The other end of the body 1 i.e., the end with the cap 12, is then pulled in such direction as to extend the length of the two bodies 1 and 5. The application of the pulling tension will progressively extend the length of the two bodies from the above mentioned folded position and in so doing will increase the internal volume of the bodies 1 and 5. This volumetric increase will produce a reduction in the internal air pressure so that air is drawn into the interior of the bodies by way of the valve 11. The induction of the air continues until the bodies have been extended to the positions shown in Figures 1 and 2.

Figures 3 and 4 schematically illustrate the structure at an early stage in the pulling-out process which terminates when the structure has been fully extended in the longitudinal direction or lengthwise of the bodies 1 and 5.

In relation to Figures 3 and 4 it will be noted that the structures are both partially inflated and that the material of the body 1 between the rings 2 and 4 and between the rings 4 and 3 is still sagging. These portions of the body are referenced 13 and 14.

Since, in practice, the resistance to air flow is proportional to the air flow area it follows that it is desirable to provide an air inlet area which is as large as possible in relation to the diameter of the body 1. As is schematically shown in the Figures the area of the valve is approximately equal to that of the cross sectional area of the body. In the Figure 4 the air flow path is indicated by the arrow A.

By the time the end 12 has been pulled sufficiently to extend the bodies 1 and 5 they will have assumed the shape that they have when pressurised to a suitable pressure above atmospheric pressure. This condition is shown in Figures 1 and 2.

As will be seen from these Figures the rings 2, 3 and 4 are at their maximum separation and the body 1 is generally cylindrical, whilst the body 5 has a cross section which progressively changes from a circular form adjacent to the end 6 of the body 1 to a flat tighly coosed linear shape at the spindle 8.

In addition, the mode of closing the valve 11 will depend upon the construction of the valve. That is to say the operation of the valve can be manual or automatic.

The particular stage of the inflation of the structure as shown in the Figures 1 and 2 can be regarded as the completion of a first phase of the inflation of the structure and, in practice, is the one which involves the induction of the greater part of the air required to inflate the structure. Thus at this point the bodies 1 and 2 will have been inflated to a pressure at or just below atmospheric pressure.

In the event that the internal air pressure at the end of the first phase is not sufficient for the intended use of the structure it will be necessary further to pressurise the structure.

Conveniently, this additional pressurisation of the structure can be produced by reducing the internal volume of the structure. If thought necessary such volume reduction effect can be augmented 1 by pumping, by connecting a pressurised air supply or by reducing the internal volume of the structure. It will be understood that suitable nipples, not shown, would be provided for the attachment of pumps or pressurised air supplies.

In the embodiment illustrated in the Figures 1 to 6, this pressurisation of the structure is effected by reducing the volume of the structure, and is carried out by rolling the body 5 onto the spindle 8. Other arrangements could be used such as pulling the body 5 through the nip between two rollers, or by pads or the like pressing upon the wall of the body 5.

Figures 5 and 6 depict the condition when the pressure inside the body 1 is above atmospheric and is at a value sufficient to produce the desired degree of rigidity in the body 1. It will be understood that since the material of the body is, for example, a rubberised fabric the body does not bell outwardly between the adjacent pairs of support rings 2,3 and 4. When the structure has been inflated to this condition the structure is regarded as being fully inflated.

Since a part of the body 5 is rolled onto the spindle 8 to reduce the volume the pressure levels produced within the overall structure of the bodies 1 and 5 will be related to the amount of the body 5 rolled onto the spindle.

Means, not shown, are provided for locking the spindle in the required position. After the rolling-up process the handle 10 will be removed or folded according to the construction thereof.

It will be realised that so far the description has been concerned with the inflation of a tubular structure and that in practice more complex structures would be involved in connection with articles such as boats. However, for the purposes of understanding and considering the possibilities of the features of the invention it is proposed to discuss various modifications of and extensions to the simple tubular structure shown in Figures 1 to 6, and then to discuss the application of the features of the invention to more complex articles such as boats.

In a first variation of the air inlet valve, the latter is located in the secondary body 5.

With this arrangement the early stages in the inflation are arranged to open the valve and the early stages in the subsequent volume reduction are arranged to close the valve against further admission of air.

A particular embodiment of this form of inlet valve arrangement is schematically illustrated in Figures 7,8 and 9. From these Figures it will be seen that the body 5 is provided with an end section 15 having a smaller cross section than the remainder of the body 5. The free end of the section 15 is connected to the spindle 8. A bar 16 is secured to the section 15, the bar can be conveniently regarded as defining the transition between the section 15 and the remainder of the body 5. An air opening 17 is formed in the wall of the section 15, this opening 17 being of any desired shape.

The inflation of the body 5 and of course the main body 1 is effected in the manner previously described.

Thus after reaching the end of the first phase, i.e., the fully open condition has been attained, the rolling-up process of the body 5 is commenced. Since the air inlet 17 is located near to the spindle 8 the air inlet is, at a very early state in the rolling-up process rolled onto the spindle. When the section 15 is fully rolled the bar 16 will have been rolled into the layers of rolled-up body section 15.

It will be apparent that the pressure of the air in the bodies 1 and 5 will be exerting a pressure which tends to act in the nip of the body 5 in the immediate location of the rolled-up portion. This pressure, in practice, exerts a force on the bar 16 which tends to push the bar 16 firmly against the layer of the body section 15 previously rolled onto the spindle.

It thus follows that the narrowest part, namely the section 15 is squeezed between the bar 16 and the spindle 8. This is because the force exerted on the outer faces or aspect of the bar, apart from any forces arising from the nature of the material of the section 15, is proportional to the surface area of the relevent faces of the bar 16 and the pressure within the body 5. This force is balanced by the force exerted on the inner faces or aspect of the bar 16 by the rolled-up parts of the body section 15 and the body 5. However, since the length of the bar 16 pressing against the smaller cross section of the body section 15 is shorter than the length of the bar subjected to pressure from the body 5 the pressure tending to keep the narrow section 15 collapsed is greater then the forces tending to unroll the tube section 15.Thus the resultant forces tend to maintain the air inlet 17 closed after the bar has been rolled into the position shown in Figure 9 in which the bar is wrapped in the rolled-up layers of the section 15.

Whilst, in practice, it is convenient for the material forming the body 5 or its extension 15 in the vicinity of the valve orifice or opening to be suitable for making a gas tight joint such material can be located at any other location of the body 5 and so arranged that when the section is rolled up air is prevented from flowing along the section 15 towards the valve opening 17. In other words, the material in question forms a seal when in a rolled-up condition as prevails in the section 15.

In a variation of the above described arrangement in which the valve 11 is located in the body 5, the valve need not actually be sited in the body but may be partly or wholly located in the spindle 8 or in an extension, not shown, of the spindle.

A further variation of the construction and mode of use of the secondary body 5 is shown in Figures 10 and 11. In this variation a short portion 18 of the body 5 adjacent to the spindle 8 is composed of a material different from that used for the remainder of the body.

The material is chosen for its particular suitability as an air valve material and for making an air tight seal. For this reason the material of the length 18 is a fairly soft elastomer such as rubber or plastics materials.

A valve opening 19 is formed in the portion 18. Conveniently the marginal edges of the opening 19 are thickened. In addition the end 20 of the portion 18 that is to be attached to the spindle 8 is thickened or provided with a beaded edge 21 which is engageable in a groove 22 provided in the spindle 8. Side flanges 23 provided at each end of the spindle serve to guide the portion 18 during the early stages of the rolling-up process.

A guide ring 24 loosely circumscribes the portion 18. This guide ring is carried from arms 25 pivotally supported from stub shafts 26 arranged co-axially with the axis of the spindle 8.

A handle 27 is connected to rotate the spindle. The handle can be pivotally connected to the spindle so as to be foldable between a stowed position and an operational position, which is shown in the Figures 10 and 11. Alternatively the handle can be readily removable for stowage purposes.

A ratchet like mechanism 28 is provided between the arm 23 and its associated stub shaft to allow rotation in a required direction and to stop rotation in the reverse direction.

The mechanism is such as to allow for reverse rotation of the handle so as to enable both the rolling-up of the body 5 and the unwinding thereof.

A ring 29 is provided for enabling connection of a line attachment clip, not shown, provided at the end of a line, not shown, for enabling the positional anchoring of the winding mechanism when in operation.

To wind the portion 18 onto the spindle the handle 27 is rotated in the appropriate direction. During this operation the assembly of the arms 23 and the ring 24 serve to guide the portion 18 uniformly onto the spindle. As has been previously discussed the valve opening is automatically wound into the rolled-up portion during the winding or rolling operation. At the end of this operation the mechanism 28 is set so as to lock the spindle against further rotation.

Furthermore, by providing the mechanism with a free-wheel action the winding or rolling-up process can be assisted by allowing the operator to employ a back-and-forth operation of the handle at the later stages of the pressurisation. If desired, reduction gearing arrangements, not shown, can be provided for facilitating the turning of the spindle against the resistance of the pressure being produced within the body 1.

If thought convenient a variable gear arrangement can be provided to permit selection of a suitable ratio according to the stage of inflation of the body 1 being inflated.

In practice, it is not necessary for the secondary or excess volume bodies of the various embodiments so far discussed to have a constant diameter. If desired, the diameter thereof can be arranged to decrease progressively to avoid undue increase in the force necessary to maintain the rolling-up of the secondary body so as to reduce the volume thereof as the internal pressure increases during inflation.

If desired, pressure relief valves, not shown, can be provided in the main body 1 or in the excess volume body 5 so as to avoid over pressurisation as a result of winding too much of the body 5 onto the spindle. This facility also allows the body 5 to be fully wound or rolled-up so as to avoid surplus excess volume body from excessively hanging from the main body.

The use of the pressure relief valve or valves provides for various possibilities in reducing the amount of work necessary to adequately inflate the body 1. Thus the pressure relief valve can be set to release air when the internal air is at a required pressure so that the excess volume body 5 can be fully rolled-up.

If desired a predetermined amount of the body 5 can be left unrolled so as to provide a means of supplying make-up air from the main body to accomodate any losses through leakage or seepage through the walls of the body.

So far the description has been concerned with the inflation of an inflatable structure comprising a simple tubular body 1 and associated excess body 5. In practice, most inflatable articles to which the features of the invention would be applied would be of a more complex form and construction. For example, the structures would more than likely include two or more main bodies or a single body of other than cylindrical form.

The inflation of such multiple body structures can be by individually inflating each body by providing each main body with its own secondary or excess volume body.

Alternatively a single secondary or excess volume body can be connected to pressurise more than one main body. The use of a single excess volume body to pressurise more than one main body enables the pressure in the main bodies associated therewith to be balanced pressurewise relatively easily. However, an important factor to be taken into account is the need to be able to prevent air flow from one main body to another so that in the event of leakage in one main body the others would not automatically deflate.

To avoid this difficulty the air derived from the excess volume body can be retained in a separate air tight compartment which remains deflated throughout the first stage of the inflation and into which compartment air is forced during the roll-up operation on the excess volume body. It will be understood that as the excess volume body does not connect directly with the interior of the associated main bodies separate air inlet valves would have to be provided for all of the main bodies and the excess volume body.

An alternative possibility in preventing air flow from one main body to another is to provide one-way valve means between the associated excess volume body to each of the associated main bodies which allow passage of air into the main bodies but not in the reverse direction.

The embodiments of the main body structures so far described have all been concerned with rectilinear arrangements. However in practical applications of structures incorporating features of the invention nonlinear shapes are likely to be required.

Furthermore, it may not be possible to arrange the excess volume bodies in line with their associated main bodies so that the excess volume bodies may be set at an suitable angle to the aixs of the associated main body.

Referring now to Figure 12 this illustrates an inflatable structure in the form of a boat which has non-linear main bodies and also non-inline excess volume bodies.

As will be seen the structure of Figure 12 includes two main bodies 31 and 32 respectively including a cylindrical side wall form ing portion 31A and 32A, a curved prow forming portion 31 B and 32B and a conically terminated end providing a stern part 31C and32C.

The curved end portions 31A and 32A are joined together and combine to form the prow of the boat. The connection can either be so that the two bodies 31 and 32 are pneumatically separate or such that they are pneumatically connected.

The stern forming end portions are interconnected by a flexible transom 33. A floor 34 of flexible material forms the bottom of the boat.

A plurality of support rings or hoops 35 are provided inside the main bodies 31 and 32 at the places indicated. These rings serve to set the tubular form of the main bodies throughout the first phase of the inflation. It will be appreciated that the Figure illustrates the boat at the end of the first phase of the inflation. These rings can be formed of metalorplastics, or can be in the formed of elastomeric solid annuli. Line attachment rings 36 and 37 are provided at the prow and the conical ends 31 C and 32C.

A secondary or excess volume body 38 connects with the main body 31 and a similar body 39 connects with the body 32. Inlet valves for the inflation air are provided.

These valves are not shown in the Figure 12.

The free ends of the bodies 38 and 39 are provided with line attachment rings 40. It will be understood that, in practice, arrangements will be provided for rolling-up the bodies 38 and 39.

A line 41 is secured to the ring 36. Lines 42 are secured to the rings 37 and lines 43 are secured to the rings 40. The lines 42 and 43 are connected in pairs, and the pairs of lines are joined to a common line 44. The arrangement of the lines 42, 43 and 44 provides a bridling system for enabling simultaneous connection of the main and secondary bodies to an anchorage for inflation purposes.

To inflate the boat the line 44 or 41 is anchored and the other line 41 and 44 is pulled so as to exert tension upon the various bodies 31, 32, 38 and 39, in the longitudinal direction thereof. It will be understood that the boat would have been suitably folded at the end of a previous deflation. This pulling out results in the first stage of the inflation process and it is this particular stage that has been shown in Figure 12.

The rear end of the boat can be braced, if desired, by a transom board, not shown, which is located adjacent to the flexible transom 33. The transom 33 could be adapted to provide location means for a rigid board.

It should be noted that since during the pulling on the line 44 or 41 transverse forces have not been employed it is likely that the boat may not have assumed its operational shape in that the stern ends 31C and 32C may have been pulled close together and the prow distorted. However, this condition is rectified during the pressurisation operation.

This operation is carried out by reducing the volume of the secondary bodies 38 and 39 in the manner previously described in relation to previous Figures.

Instead of providing two separate main bodies in order to produce a boat like shape a single main body can be so shaped as to form the periphery of the boat. It will be realised that the extension of such a structure could, during the first stage of the inflation create some difficulties since the pulling out action instead of opening out the main body could act is such a way as to produce folds or creases which prevent the opening out of the main body. It, therefore, follows that to pull out some structures whilst maintaining or establishing the transverse body shape it may be necessary to exert transverse tension forces as well as the longitudinal pulling forces. However, it would be difficult for one person to exert the required forces.

As a means of overcoming this difficulty it is proposed to provide the main body with struts which engage with suitable positioned pockets provided on the wall owl the main body. These pockets could be spaced around the periphery of the main body i.e., in the vicinity of the support rings and thus allow the main body to be pulled out section by section and struts to be fitted to the sections as they are extended to provide the required support.

A further possibility is to provide foldable strut assemblies which are arranged to be able to exert in a direction transverse to the longitudinal direction of the associated main body. The assemblies are interconnected with tension lines which are used for the pulling the structure during the first phase of inflation so that the strut assemblies are automatically opened out to produce the required transverse forces.

A practical embodiment incorporating the various features of the invention namely, the main bodies, the excess volume bodies, the winding mechanisms, and the strut assemblies will be considered in relation to Figure 13. In this Figure the structure to be described is an inflatable boat and is shown in the Figure when at the end of the first phase of the inflation process.

The boat is essentially formed from a single main body 46 which includes two side wall sections 47 and 48, two prow forming sections 49 and 50 and a stern section 51.

Two secondary or excess volume bodies 52 and 53 operationally connect with the main body wall sections 47 and 48.

It will be apparent that the pulling-out of the boat as so far described would have the effect of pulling the side walls together and thus deforming the prow and stern to such an extent that the amount of air induced during the first phase of the inflation operation would not necessarily be sufficient to achieve the required degree of inflation at the end of the first phase so that the secondary bodies would not be capable of producing the desired degree of pressurisation. This effect is due to the absense of the above mentioned transverse forces.

To overcome this difficulty it is proposed to provide pivoted strut assemblies 54 and 55 at the prow and stern respectively of the boat. The strut assembly 54 includes two struts 54A and 54B pivotally connected together in end to end relationship by a hinge arrangement 54C.

The assembly 54 is located inside the prow forming sections 49 and 50 and is mounted such that the free ends of the struts 54A and 54B engage in sockets or the like 56.

The assembly 55 likewise comprises two struts 55A and 55B pivotally connected in end to end relationship by a hinge arrangement 55C. The struts have their free ends engaged in sockets 57.

The hinge arrangement 54C is connected by a line 58 to the hinge arrangement 55C and the latter is connected by the line 58 to an external tensioning line 59. The prow of the boat is connected by lines 60 to a line 61.

To inflate the boat as so far described to the end of the above mentioned first phase of inflation which is shown in the Figure one of the lines 59 or 61 is anchored and pull is exerted on the other line 61 or 59. In view of the connection between the lines 58, 59 and 61 and the hinge assemblies the pulling out of the main body 46 will simultaneously exert tension on the strut assemblies in such manner as to pull the struts thereof into their in-line position and thus exert transverse pressure to the side wall sections 47 and 48 to move them into their correct positions.

At the end of the first phase of the inflation the main body 46 will be pressurised by any of the previously dicussed methods. In the Figure 13 the winding handles for the bodies 52 and 53 are schematically shown at 62 and 63 respectively.

A floor 64 of flexible material bridges the main body.

Stiffening rings 65 are provided at convenient locations inside the main body. In the Figure 13 only those rings 65 located at discontinuity points of the main body are shown. Further rings, not shown, can be provided at suitable locations along the length of the main body side wall, prow and stern sections.

A seat forming main body 66 and associated secondary or excess volume body 67 together with the associated winding mechanism 68 extends transversely of the main body 46. The end regions of the body 66 and the free end of the body 67 are anchored to the main body 46 so that the first phase of the seat inflation occurs with that of the main body 46. The seat body 66 is provided with a pivoted strut assembly 69 including struts 69A and 69B connected in end-to-end relationship by a hinge arrangement 66C. The free ends of the struts engage in pockets or the like in a manner similar to the struts of the assemblies 54 and 55. The hinge arrangement 69C is connected to the tensioning line 58 so that all three strut assemblies are constrained to move together.

Air inlet valves 70, 71 and 72 are respectively provided in the main bodies 47,48 and 67.

When it is desired to deflate the boat the various winding mechanisms of the bodies are operated to unwind the rolled-up portions of the secondary bodies and the valves 70, 71 and 72 are opened to release air. The bodies are progressively flattened to drive out the air. Since the air flow paths are relatively large for the reasons previously considered the air within the main bodies is able readily to escape. The three strut assemblies are folded so that the struts thereof lie sideby-side. The support rings 65 are suitable displaced to facilitate the deflation operation.

The boat is then folded lengthwise so that the strut assemblies are one above the other.

Afterwhich the folded boat can be retained in the folded position by means of straps or the like.

To inflate the boat of Figure 13 the boat is unfolded and one of the lines 59 or 61 is anchored. Tension is applied to the other line 61 or 59 so as to pull the boat in said first phase condition. The bodies are then pressurised by reducing the volumes of the bodies 52 and 53. Similarly the seat body is pressurised by reducing the volume of the body 67.

It will be appreciated that with the boat structure of Figure 13 the boat is capable of floating as soon as the first phase of the inflation has been completed so that the pressurisation can be effected whilst the boat is afloat. This feature is of advantage when the boat is required in an emergency.

Although the Figure has illustrated a construction in which the main body 46 is a continuous structure it is possible to divide the interior into separate compartments by suitable baffles or valves. In this case the secondary bodies would each be associated with the inflation of a part of the main body 46.

In those constructions incorporating support rings or hoops which assist in shaping an inflatable body at right angles to its longitudinal axis the support rings can be provided with a vertically arranged support or reinforcing bar. Such reinforcing bars can be of a telescopic construction which defines a minimum length suitable for the first inflation phase conditions and an extended length to accord with the degree of pressurisation.

In a further arrangement additional longitudinally directed struts could be used to assist the opening out operation. The struts could be of such construction as to allow folding in the longitudinal direction but which provide support to the material of the associated main body to prevent sagging of the material during the pulling-out phase.

The struts can be permanently fitted or selectively mountable in sockets provided on the bodies to allow attachment as and when required.

Although the inflatable structures incorporating the features of the invention are intended to be inflatable and pressurisable with out the need for external pressurised air supplies it is apparent that means can be provided for enabling connection or pressurised gas supplies to be connected to the main bodies. Furthermore, suitable pump connection nipples or the like can likewise be provided.

In relation to the roll-up form of valve discussed above it has been found that an adequate seal can be obtained just by the rolling-up of the fabric in cases where the bar has been omitted. Thus the inclusion of the bar can be a matter of empirical selection.

When commencing the winding-up of the auxiliary bodies it may be found convenient to give the body a pull prior to the windingup process is commenced. This action will remove any creasing or the like which could impair the efficiency of the sealing producing by the winding-up process and also lead to a smoother winding-up process, particularly in connection with the use of the winding handle assemblies.

In a modified construction of the apparatus of the invention the structures to be inflated can be formed such that the associated auxiliary bodies provide a pumping facility in addition to their hitherto described function of pressurising the associated main body. Alternatively the inflatable structures can be provided with one or more additional auxiliary bodies providing the pumping facility.

This modified construction is schemati cally shown in Figures 14 and 15. In these Figures for convenience the modified arrangement is shown in conjunction with a main body arrangement.

Thus in these Figures a main body 75 has a auxiliary body 76 which connects therewith in the manner shown. An aperture 77 is formed in the wall so as to provide an air communication path between the bodies 75 and 76. A first valve 78, which can be a flap valve, allows air to pass from the body 76 to the body 75.

The free end of the auxiliary body 76 is provided with a rolling or winding-up arrangement 79 which is conveniently similar to those previously described.

An air inlet orifice 80 is provided in the body 76 near the free end thereof. A second valve 81 operationally co-operates with the orifice 80.

The above described construction including the auxiliary body 76 and the valves 78 and 81 provides an air pump arrangement whose pump chamber is formed by the body 76 and the inlet and outlet valves by the valves 81 and 78 respectively.

The main body 75 is suitable reinforced by the support rings or other elements mentioned hereinafter these supports are schematically indicated at 82.

It will be understood that the valve 78 will differ in several important aspects from the air inlet to the main body. These differences include 1. There is no limitation to the size of the valve opening which may be used. This allows substantially unrestricted inlet air flow.

2. The valve is only required to be able to withstand a low pressure. It will not have to be able to prevent the escape of air after pressurisation or when the air pressure starts to rise appreciably above atmospheric.

3. Thereis no absolute requirement for the valve to be fully airtight when closed. A small amount of leakage would be acceptable.

4. Preferably, the action of the valve should be such as not to restrict the flow of air. From the above it will be apparent that the valve 78 can be of simple construction thus a lightweight flap valve can be used.

In the case of the formation of the valve 81 it is convenient to consider the form of this valve in relation to the operational conditions likely to be met. The conditions can be conveniently considered in two stages.

Stage 1. Initially while the interior of the main body to be inflated is being filled by air as a result of the expansion thereof from the stowed or folded state and before pressure begins to rise the valve criteria are very similar to those mentioned in relation to the valve 78.

Stage 2. As pressure within the main body increases the valve must be able to withstand the increased pressure. Furthermore the sealing effect produced has to be able to air tight as no leakage is acceptable at this stage.

With a view to avoiding complicated constructions for such a valve the valve is essentially in the form of a two part construction.

The first being of a simple form for dealing with the first stage. This form can be a simple flap valve as suggested above. The second part can comprise an arrangement for her metically sealing the flap valve such as a cap or other sealing means or use may be made of the winding or rolling-up technique discussed above. In the particular pump construction disclosed the rolling-up technique is used.

In Figure 15 the mounting of the flap valves is shown in some detail in schematic form. The valve 78 includes a rectangular piece of material whose upper edge 83 is secured to the main body 75 and whose lower edge 84 is suitably stiffened to assist in retaining the shape of the flap valve 78.

Similarly, the valve 81 includes a rectangular piece of material. One edge 85 is secured to the auxiliry body and the other edge 86 is stiffened.

The main body is inflated in the following manner. The main body is unfolded and pulled out in the manner previously discussed in relation to the main bodies of the various constructions described above.

The degree of filling of the main body at the end of this phase will depend on how closely its shape corresponds to its fully inflated shape. This initial inflow of air may be achieved very rapidly because of the low resistance to air flow of the valves 78 and 81.

The opening tension can now be released from the bodies any loss of air will be resisted by the action of the valves. The auxiliary body 76 may now be alternately squeezed and expanded in order to force air which it contains into the main body 75. During this pumping action large volumes of air at low pressure are being introduced into the main body 75.

When the main body 75 has reached its proper full shape and pressure it begins to rise (or slightly earlier if desired) the auxiliary body is rolled-up by the arrangement 79.

This has the following effects.

1. The inlet valve orifice 80 is closed and sealed.

2. Pressure within the main body begins to rise. The extent of the pressure increase is dependent on the relative size of the auxiliary body 76. The ease of operation depends upon its mechanical advantage.

When the auxiliary body has been rolledup it can be secured to the side of the main dboy by any convenient means.

It may be desirable in some embodiments to design the auxiliary body to be of such construction that when it is fully rolled-up adequate pressure within the main body has not been reached. Alternatively, this may happen in the case of a user without adequte physical strength fully to roll-up the auxiliary body under pressure. In such a situation the inflation may be completed by means of a conventional pump or source of pressurised gas.

Deflation of the above described arrangement can be achieved in the following way. The auxiliary body is unrolled. The stiffened edges of the flaps 78 and 81 are each pulled through the associated orifice 77 and 80 thus rendering the valves inoperative and thus allowing unhindered passage of air in either direction.

In the various embodiments described above the reinforcements of the main bodies have been shown as rings or complete hoops.

In practice, it may be convenient to provide partial hoops which extend only part way around the wall of the main body.

To assist stowage the rings may be constructed as to be foldable across a diameter.

That is to say they can be formed from two separate arcuate parts suitable pivotally connected to form a ring when in the extended positions. Clearly, more that two arcuate parts can be similarly arranged.

The reinforcing rings can be made from any suitable material for example, metal, plastics, those with a rubber-like characteristic such as a solid rubber ring, rings with a sorbo-rubber formation which tend always to assume a predetermined shape.

In a variety of the reinforcement the main body can be provided with an internal framework which includes a plurality of main elements e.g., rings or hoops which are arranged transversely of the direction of extentsion of the main body and which are interconnected with foldable structs or the like which allow the framework to concertina or otherwise collapse to allow stowage. With such an arrangement the pulling-out of the main body into shape is assisted by the internal framework.

The frameworks can be arranged to strech the materail or fabric into a required shape.

In a complex main body formation the frameworks can be such as to provide support for the main bodies interconnecting two or more other main bodies directed transversely thereto. Thus the frameworks contemplated are capable where required of expansion in transverse directions.

The mechanical forms of framework can be replaced by or supplemented by pneumatically or hydraulically erectable arrangements. Such arrangements can include a 'framework' of inflatable tubes which can be air inflated by for example a conventional pump or an air supply which can be of relatively small volumetric content, to erect the 'framework' and thus expand and support the fabric of the associated main body and thus assist in establishing its erected shape.

In a further modification the rings of hoops can be provided with radially directed support elements such as radially directed arms connecting with arcuate sections which combine to provide the required shape of reinforcement.

WHAT I CLAIM IS: 1. An air inflatable structure comprising

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (25)

**WARNING** start of CLMS field may overlap end of DESC **. metically sealing the flap valve such as a cap or other sealing means or use may be made of the winding or rolling-up technique discussed above. In the particular pump construction disclosed the rolling-up technique is used. In Figure 15 the mounting of the flap valves is shown in some detail in schematic form. The valve 78 includes a rectangular piece of material whose upper edge 83 is secured to the main body 75 and whose lower edge 84 is suitably stiffened to assist in retaining the shape of the flap valve 78. Similarly, the valve 81 includes a rectangular piece of material. One edge 85 is secured to the auxiliry body and the other edge 86 is stiffened. The main body is inflated in the following manner. The main body is unfolded and pulled out in the manner previously discussed in relation to the main bodies of the various constructions described above. The degree of filling of the main body at the end of this phase will depend on how closely its shape corresponds to its fully inflated shape. This initial inflow of air may be achieved very rapidly because of the low resistance to air flow of the valves 78 and 81. The opening tension can now be released from the bodies any loss of air will be resisted by the action of the valves. The auxiliary body 76 may now be alternately squeezed and expanded in order to force air which it contains into the main body 75. During this pumping action large volumes of air at low pressure are being introduced into the main body 75. When the main body 75 has reached its proper full shape and pressure it begins to rise (or slightly earlier if desired) the auxiliary body is rolled-up by the arrangement 79. This has the following effects. 1. The inlet valve orifice 80 is closed and sealed. 2. Pressure within the main body begins to rise. The extent of the pressure increase is dependent on the relative size of the auxiliary body 76. The ease of operation depends upon its mechanical advantage. When the auxiliary body has been rolledup it can be secured to the side of the main dboy by any convenient means. It may be desirable in some embodiments to design the auxiliary body to be of such construction that when it is fully rolled-up adequate pressure within the main body has not been reached. Alternatively, this may happen in the case of a user without adequte physical strength fully to roll-up the auxiliary body under pressure. In such a situation the inflation may be completed by means of a conventional pump or source of pressurised gas. Deflation of the above described arrangement can be achieved in the following way. The auxiliary body is unrolled. The stiffened edges of the flaps 78 and 81 are each pulled through the associated orifice 77 and 80 thus rendering the valves inoperative and thus allowing unhindered passage of air in either direction. In the various embodiments described above the reinforcements of the main bodies have been shown as rings or complete hoops. In practice, it may be convenient to provide partial hoops which extend only part way around the wall of the main body. To assist stowage the rings may be constructed as to be foldable across a diameter. That is to say they can be formed from two separate arcuate parts suitable pivotally connected to form a ring when in the extended positions. Clearly, more that two arcuate parts can be similarly arranged. The reinforcing rings can be made from any suitable material for example, metal, plastics, those with a rubber-like characteristic such as a solid rubber ring, rings with a sorbo-rubber formation which tend always to assume a predetermined shape. In a variety of the reinforcement the main body can be provided with an internal framework which includes a plurality of main elements e.g., rings or hoops which are arranged transversely of the direction of extentsion of the main body and which are interconnected with foldable structs or the like which allow the framework to concertina or otherwise collapse to allow stowage. With such an arrangement the pulling-out of the main body into shape is assisted by the internal framework. The frameworks can be arranged to strech the materail or fabric into a required shape. In a complex main body formation the frameworks can be such as to provide support for the main bodies interconnecting two or more other main bodies directed transversely thereto. Thus the frameworks contemplated are capable where required of expansion in transverse directions. The mechanical forms of framework can be replaced by or supplemented by pneumatically or hydraulically erectable arrangements. Such arrangements can include a 'framework' of inflatable tubes which can be air inflated by for example a conventional pump or an air supply which can be of relatively small volumetric content, to erect the 'framework' and thus expand and support the fabric of the associated main body and thus assist in establishing its erected shape. In a further modification the rings of hoops can be provided with radially directed support elements such as radially directed arms connecting with arcuate sections which combine to provide the required shape of reinforcement. WHAT I CLAIM IS:

1. An air inflatable structure comprising

a main body which is required to be air pressurised and which is collapsible or otherwise foldable from its inflated shape to a stowed configuration; an elongate tubular auxiliary body connected at one end to the main body, the auxiliary body being pressurisable by air and collapsible or otherwise foldable from an extended shape for the purposes of stowage or the like; an air flow path between the two bodies; an air inlet arrangement permitting admission of air into the structure, and means for driving air from the auxiliary body in a direction from the free end thereof, the arrangement being such that on displacing both said main and said auxiliary bodies from their collapsed or stowed condition respectively into their inflated form and elongated condition air is inducted into both said bodies, and such that on operating the air driving means so as to reduce the internal volume of the elongate auxiliary body in a direction from the free end thereof towards the end connecting with the main body the air inlet arrangement closes against air flow into the structure and following such closure further reduction of said internal volume produces a corresponding increase in the pressure within the main body.

2. An air inflatable structure as claimed in claim 1, and including valve means in said air flow path whereby air can be retained in the main body to allow further induction of air into the auxiliary body thereby to enable further pressurisation of the main body by further driving of air from the auxiliary body.

3. An air inflatable structure as claimed in claim 1 or 2, wherein the free end of the auxiliary body is wound or rolled-up from the free end thereof thereby to reduce the volume thereof, the arrangement being such that the degree of pressurisation of the main body is related to the amount of auxiliary body wound or rolled-up.

4. An air inflatable structure as claimed in claim 3, wherein the auxiliary body is wound or rolled onto a spindle, the latter being adapted to receive rotational drive from a handle or the like.

5. An air inflatable structure as claimed in claim 4, and including gear drive arrangements for facilitating the rotational of the handle or the like.

6. An air inflatable structure as claimed in claim 3 or 4, including means for allowing a back and forth action for the operation of the handle or the like.

7. An air inflatable structure as claimed in any one of claims 3 to 6, in which the air inlet means for the inducted air is provided in the auxiliary body, the arrangement being such that the air inlet means is closed to air flow shortly after commencing the winding or rolling of the auxiliary body.

8. An air inflatable structure as claimed in any one of claims 1 to 7, and wherein relief valve means is provided in the main body to allow release of air when the pressure of the air in the main body has attained a predetermined value, the arrangement being such that the auxiliary body can be wound or rolled-up to a required size with out overpressurising the main body.

9. An air inflatable structure as claimed in any one of claims 1 to 8, and including means for providing a self-supporting facility for the main body during the inflation thereof, the arrangement being such as to enable the main body to assume its shape during said expansion or unfolding.

10. An air inflatable structure as claimed in any one of claims 1 to 9, wherein the main body is of elongate form, and wherein the body is shaped so as to provide a non-linear form.

11. An air inflatable structure as claimed in any one of claims 1 to 10, and including at least two main bodies and an auxiliary body for each of said main bodies.

12. An air inflatable structure as claimed in any one of claims 1 to 9, wherein the main body defines the outline of a boat.

13. An air inflatable structure as claimed in any one of claims 1 to 9, wherein the main body defines the prow and side walls of a boat, and wherein spacer means are provided for setting the separation of the stern ends of the side walls.

14. An air inflatable structure as claimed in claim 13, wherein each side wall has an auxiliary body associated therewith.

15. An air inflatable structure as claimed in any one of claims 1 to 9, wherein the main body defines the prow, the two side walls and the stern of a boat.

16. An air inflatable structure as claimed in claim 15, wherein each side wall has an auxiliary body associated therewith.

17. An air inflatable structure as claimed in claim 10, 13 and 16, and including means for exerting forces upon the main body in a direction transverse to the principal direction of any forces used to expand or unfold the main body from its collapsed or folded condition.

18. An air inflatable structure as claimed in claim 17, wherein said means includes foldable strut assemblies provided at those regions of the main body at which it is necessary to exert said transverse forces during the inflation of the main body.

19. An air inflatable structure as claimed in claim 18, and including means for linking the actuation of the strut assemblies with the expansion or unfolding of the main body.

20. An air inflatable structure as claimed in any one of claims 1 to 17, and including a readily foldable mechanical framework adapted for extension from a folded position to a main body wall supporting relationship.

21. An air inflatable structure as claimed in any one of claims 1 to 17, and including a pneumatically or hydraulically erectable fromework for supporting the walls of the main body.

22. An air inflatable structure as claimed in any one of claims 1 to 21, wherein one or more auxiliary bodies is provided with valve mens at the join thereof with the associated main body, the arrangement being such as to convert the auxiliary body into a pump arrangement.

23. An air inflatable structure constructed and arranged to operate, substantially as hereinbefore described with reference to Figures 1 to 6, Figures 7 to 9, Figures 10 and 11, Figure 12, Figure 13 or Figures 14 and 15 of the accompanying drawings.

24. An inflatable boat structure when including an inflatable structure as claimed in any one of claims 1 to 23.

25. A method of inflating an inflatable structure substantially as hereinbefore described.