Device for stabilizing an inflatable structure

The device comprises at least one pair of flexible ballasts which extend laterally along the length of the inflatable structure and each comprise an orifice, acting as a vent, situated at the front, and a scoop system situated at the rear. Between the ballasts, at least one pipe connects the cavities of said ballasts to equalize their level of fill and the stagnation pressure of the water obtaining in said cavities when the inflatable structure is pulled along in the inflated state. This scoop system consists of a component moulded in a rigid or semirigid thermoplastic or is made of an assembly of cutouts from a flexible material of watertight fabric. This scoop system is bonded and/or welded to the ballast.

RELATED APPLICATIONS

The present application is a National Phase entry of PCT Application No. PCT/FR2011/050227, filed Feb. 4, 2011, which claims priority from FR Application No. 10 58956 filed Oct. 29, 2010, which applications are incorporated by reference herein in their entirety.

FIELD OF THE INVENTION

The present invention relates to a device for stabilizing an inflatable structure and in particular an inflatable structure intended to be pulled along in the inflated state by a motor boat.

BACKGROUND OF THE INVENTION

A floating inflated structure of cylindrical or similar shape does not have an inherent stability. It requires some sort of ballast in order to be able to take and hold its position, either in a static situation or even in a dynamic situation, during its movement over the water.

In certain conditions of use outside the water such as during periods of transport, for example, the ballast can constitute an inconvenience owing to its bulk and weight.

This problem can equally be found again on classic motor boats such as that described in the document FR 2 633 581. In this document the motor boat comprises a longitudinal keel which is mounted beneath and in the centre of the hull, the said keel being provided in the form of a cylindrical pocket formed with a deformable watertight flexible material which comprises at one of its ends an orifice acting as a vent, and at its other end a fitment in the form of a scoop in order to allow automatic refilling of this pocket with water and this as soon as the boat starts to move.

SUMMARY OF THE INVENTION

The present invention proposes a fitment of this type, but for an elongated inflatable structure in the form of a large cylinder which is intended to be pulled along, in the inflated state, by a boat. The inflated structure having a diameter in the order of 2 meters or more, for example, and it has to be stabilised on the water, notably when it is moved, pulled along by a motor boat.

The present invention proposes a simple efficient means enabling ballasting of this inflatable structure so as to rapidly obtain sufficient stability which enables it to follow a safe trajectory, corresponding to that of a more classic type of motor boat, for example as described in the aforementioned French document.

The stabilizing device according to the invention is linked to an inflatable structure of a generally substantially elongated cylindrical shape, capable of being inflated with a view to its displacement and pulled along by a motorised engine. It comprises at least one pair of flexible ballasts which extend laterally along the length of the said inflatable structure and which are mounted on the structure in such a way as to be able to sink in the water simultaneously. The ballasts each comprise an orifice acting as a vent, located at the front, and a scoop system, located at the rear, with, between the rear ends of these ballasts, at the rear of the said scoop system, a pipe which links the cavities of the said ballasts in order to equalize the load and/or the total pressure of the water which reigns in the said cavities when the structure is pulled along. The cavities, when filling with water, act the role of a keel and are able to play the part of a hull in the manner of a catamaran or other, without necessarily playing the part of floats, which remains in any case with the said inflatable structure.

The ballasts are provided in the form of elongated fenders which are integral with the inflatable structure, over at least a part of their length. The ballasts are made of a flexible watertight fabric having, for example, a diameter in the order of 30 to 40 cm, in relation with that of the inflatable structure. Each fender can comprise one or more compartments, the compartments being each provided with their own scoop system. The cavities of each pair of compartments are located at the same level over the length of the said structure and are connected by a pipe to equalize the pressure and the refilling level.

According to the present invention, the junction between each equalizing pipe and the compartment of the corresponding ballast comprises a non-return valve in such a way as to place, at the level of the said equalizing pipes, elements which are capable of maintaining a geometrical shape which is adapted to their function.

According to a first embodiment of the invention, the scoop system is comprised of a scoop moulded from a rigid or semi-rigid thermoplastic material. The scoop is bonded and/or welded at the level of an orifice formed in the fabric of each ballast or each compartment, at its rear part.

According to the invention, the scoop which is made of thermoplastic material is provided in the form of a bent part which may comprise a non-return valve located at its inlet, for example.

According to another embodiment of the invention, the scoop system is comprised of an assembly of cut-outs made from a flexible material of the watertight fabric type, and more particularly several cut-out templates which are firstly assembled together by bonding and/or by welding;a first template which makes it possible to form three layers of fabric in order to produce the part corresponding to the sides of the scoop proper, one of the layers being placed head to tail between the other two;a second cut-out template which forms a fourth layer of fabric for the sides of the scoop and which partially caps the three preceding layers, anda third cut-out template which forms a reinforcement to cover the downstream part of the first cut-out template which is not covered by the second cut-out template.

Still according to the invention, the first cut-out template comprises three parts:a central part which corresponds to the two sides of the scoop proper, the sides are of triangular shape and they are connected to one another by a common web,a lateral part which forms a large sill, which large sill extends upstream and downstream of the web which links it to the said side of the scoop,another lateral part which forms a small sill, set opposite the large sill in relation to the sides of the scoop, the said small sill extends solely upstream of the web which connects it to the other side of the scoop.

The second cut-out template comprises three parts;a central part which corresponds to the two sides of the scoop proper, the sides are of triangular shape and they are connected to one another by a common web,two identical lateral parts placed either side of the central part and which each form a sill, the sill extends upstream of the web which connects it to the corresponding side of the scoop, and the surface of the sills of this second cut-out template is substantially higher than that of the small sill of the first cut-out template.

According to another design of the invention, the third cut-out template, of substantially rectangular shape, has a surface area which corresponds to twice the surface area of the downstream part of the large sill of the first cut-out template.

According to the invention, the scoop system comprises, in the ballast, covering the orifice of the scoop proper, a non-return valve comprised of a flexible member which is fixed on the interior surface of the wall of the said ballast, the flexible member, of fabric, is fitted at the level of the orifice, welded or bonded just upstream of this orifice.

The invention equally relates to the process of producing this scoop system, of flexible material as detailed above. The process consisting of:arranging the three pieces which make up the first cut-out template, one above the other, of which one is placed head to tail between the other two,overlapping the said three pieces with a piece which corresponds to the second cut-out template,bonding and/or welding the four pieces by separating the downstream parts which form part of the first cut-out template,increasing the volume of the said scoop proper,assembling by bonding and/or welding the upstream part of the sills of the pieces corresponding to the first cut-out template and to the second cut-out template,assembling by bonding and/or welding the piece which corresponds to the third cut-out template, on the downstream part of the sills of the pieces which make up the first cut-out template.

Still according to the invention, the process consists in:creating in the fabric of the ballast an opening of triangular shape with its tip turned towards the downstream part of the said ballast,bonding and/or welding the scoop system on the internal face of the fabric which makes up the ballast.

DETAILED DESCRIPTION OF THE FIGURES

FIG. 1shows an inflatable structure1which in the inflated state is pulled along by a motor-type boat2. This inflatable structure1, with compressed air, for example, is provided in the form of a large elongated cylinder whose diameter can be for example in the order of 2 meters or more. This cylinder is made by means of a flexible watertight fabric and it can comprise, as shown in the drawing, several compartments, for example three compartments.

In order to stabilize this inflatable structure1on water, there are ballasts3which extend over all or part of the length of the cylinder and in particular along the generatrices of this cylinder. The ballasts3are for example two in number and they are spaced out transversally.

The ballasts3may have a fender-type shape whose cover is equally formed from a watertight flexible fabric, preferably from the same fabric as that used to make the inflatable structure.

The ballasts3may be fitted on the wall of the cylinder forming the inflatable structure1by bonding or the like. These ballasts3are for example installed on the inflatable structure1according to the generatrices whose angular position a, in relation to the centre of the cylinder, is in the order of 90°, as shown inFIG. 2where the said inflatable structure1is shown face on.

In this embodiment, the two ballasts3are in fact placed on the external surface of the inflatable structure1in such a way that they can both sink simultaneously in the water.

As shown inFIG. 2, the ballasts3hang down laterally beneath the inflatable structure1when this inflatable structure1is for example suspended out of water.

FIG. 3shows the two ballasts3, without the inflatable structure1. The ballasts3extend parallel over the entire length of the cylinder which makes up the inflatable structure1and they form a type of catamaran with a twin hull, but with the difference that this twin hull does not float and that rather it plays the part of a ballasted keel.

The connection between the ballasts3and the inflatable structure1is formed by bonding or by any other suitable assembly means.

In order to fulfil their function of ballast and stabilization, the ballasts3comprise, as shown inFIG. 4, and in more detail inFIGS. 5 to 9, a scoop system4which allows water to be introduced automatically when the inflatable structure1is pulled along, in the inflated state, by a motor boat2.

FIG. 5shows the ballasts3viewed from below, with each scoop system4at their rear part which corresponds to the prow of the inflatable structure1.

The cavities of the two ballasts3can preferably be connected to one another at their rear end by a pipe5. This pipe5allows in particular their level of fill to be equalized as well as the total pressure of the water which prevails in the cavities of the ballasts3in order to stabilize the inflatable structure1on the water when it is being moved, pulled along by the motorboat2.

As illustrated inFIGS. 1 and 3, in order to enable their integral filling, the ballasts3comprise at their front part, level with the prow, an orifice6having a small diameter and acting as a vent. The orifice6enables the evacuation of any air which may be contained in the ballast3.

FIG. 5also shows, represented by dotted lines, an embodiment for providing compartments in each ballast3. As shown inFIG. 5, each ballast3comprises two compartments7and8; each pair of compartments placed at the front, or at the rear, is connected by a pipe for equalizing the pressures. The pair of compartments7, located at the front, is connected by a pipe5′ which is located substantially at the rear of the scoop systems4′ set at the rear end of this front pair of compartments.

Still in the case ofFIG. 5, the front part of the pair of compartments8located at the rear comprises a vent6′, shown inFIG. 1. This vent6′ is comprised of a single small orifice which enables an automatic escape of the air contained in the cavity of the ballast3gradually in proportion to the filling of the corresponding compartment with the scooped water.

The equalizing pipes5,5′ which connect the ballasts3can be of different shapes, as detailed later on in conjunction withFIGS. 10 to 14.

FIG. 6shows the protruding part of a first scoop system4. The scoop system is comprised of a scoop9which appears projecting over the lower exterior surface of the wall of a ballast3. This scoop9is positioned in an orifice10having a triangular shape which is mounted in the flexible wall of the ballast3, in an area which allows the scoop9to submerge as soon as the inflatable structure1is placed on the water.

FIG. 7shows the internal face of the flexible wall of the ballast3with, bonded on its internal surface. The scoop9is comprised, as detailed later on inFIGS. 15 to 23, of an assembly of cut-outs formed in a flexible watertight fabric, of the type which makes up the said ballasts3.

FIG. 8shows a particular embodiment of the scoop system which is fitted with a non-return valve. This scoop system comprises a flexible piece11fixed on the interior surface of the wall of the ballast3. The piece being installed level with the orifice10, welded or bonded just upstream of the opening, coming to cover this opening of the scoop in the said ballast3.

FIG. 9shows a variation of the embodiment of the scoop system4. This scoop system is comprised of a rigid scoop12, formed of a thermoplastics material, for example. It has the shape of a crank and it is fixed to the ballast3level with a cut-out10′ by any suitable means. This scoop12comprises a non-return valve13which is placed level with its inlet, for example; this valve13allows the water to be retained in the corresponding ballast3, as in the case of the scoop9fitted with the flap11, shown inFIG. 8.

FIGS. 10 to 14show an alternative embodiment of the equalizing pipes5and5′ which become the true structural elements, under pressure, to support the load1of the inflatable structure1. These equalizing pipes5and5′ can maintain a geometrical shape adapted to their function, in the form of girders, if they are fitted with anti-return valves level with their connection to each ballast3.

FIG. 12shows a valve14, of the non-return valve type, installed level with the connection between a ballast3and an equalizing pipe5, or5′, the said valve14enabling the passage in the travel sense of the said ballast3towards the interior of the pipe5, or5′.

The stabilizing device shown inFIGS. 10 and 11is similar to a catamaran. It can equally have the form of a trimaran in order to carry and support more significant inflatable structures, as shown inFIGS. 13 and 14. Three ballasts3are connected to one another by the equalizing pipes5,5′ and one inflatable structure1rests in the inflated state on the said pipes5,5′, lashed by suitable means.

The scoop system4which is comprised of the scoop9, as detailed in the followingFIGS. 15 to 23, is made from several pieces which are cut out in the flexible watertight fabric of the type used for making the ballasts3.

FIG. 15shows a first cut-out template15andFIG. 16shows an identical template15′ which has merely been presented in the way that it is assembled with two templates15, that is head to tail between these two templates15, in order to provide the method of making the scoop system4.

FIG. 17shows another piece of the scoop system4, which piece constitutes a second cut-out template16.FIG. 20shows also another piece which corresponds to a third cut-out template17.

In order to make this scoop system4, the three pieces of the first cut-out template15,15′ as shown inFIG. 18, are gathered to which is added the second cut-out template16which is shown inFIG. 17which gives a first regrouping of four pieces as shown inFIG. 19.

The first cut-out template15,15′ comprises two triangular zones which correspond respectively to the sides20and21of the scoop9proper, the said sides20and21being connected to one another by a common web22. A large sill23extends along the side20with a common web24and a small sill25extends along the side21with a common web26. The large sill23extends upstream and downstream of the side20whilst the sill25extends solely upstream of the side21, that is to say upstream of that which corresponds to the inlet of the scoop9.

The second cut-out template16, shown inFIG. 17, itself also comprises the sides20and21which make up the scoop9proper, and it equally comprises the sills27which have an identical shape, connected by the webs24and26to the sides20and21respectively.

The sills27of this second cut-out template16extend solely upstream of the sides20and21and their surface area is substantially greater than that of the small sills25of the first cut-out template15,15′.

The first cut-out templates15,15′ are assembled together flat as shown inFIG. 18, by using three pieces: two templates15and one template15′ installed head to tail between the other two.

In this configuration,FIG. 18, the scoop system4corresponds to a regrouping and to an assembly, by bonding and/or welding, of the three pieces taking care to separate the large sills23and in particular their downstream part in order to avoid their welding.

This first regrouping of the first cut-out templates15and15′ is then completed with the second cut-out template16, as shown inFIG. 19and the assembly is again bonded and/or welded in order to form the scoop system4, still flat.

The volumizing of this regrouping of the first and second cut-out templates, as shown inFIG. 21, has the effect of producing the scoop9proper, that is to say closing up the angle formed by the webs24and26of the sides20and21and bringing closer the upstream sills of the pieces corresponding to the first cut-out template15,15′ and of the piece corresponding to the second cut-out template16.

The third cut-out template17is bonded over the downstream parts of the large sills23of the first cut-out templates15,15′ in order to reinforce this part which is located at the rear of the scoop9.

At the front of the scoop9, the upstream parts of the sills23,24and27can be bonded and/or welded to fix the shape of the scoop9proper.

By being made from cut-outs of a flexible and watertight fabric of the type which makes up the ballasts3, the scoop system4is relatively flexible which enables the said ballasts3likewise to maintain a certain flexibility, particularly when they are totally inactive away from the water.

Various modifications to the invention may be apparent to one of skill in the art upon reading this disclosure. For example, persons of ordinary skill in the relevant art will recognize that the various features described for the different embodiments of the invention can be suitably combined, un-combined, and re-combined with other features, alone, or in different combinations, within the spirit of the invention. Likewise, the various features described above should all be regarded as example embodiments, rather than limitations to the scope or spirit of the invention. Therefore, the above is not contemplated to limit the scope of the present invention.