Ships – Boats – boat component – or attachment – Inflatable
Reexamination Certificate
2000-06-16
2001-04-03
Sotelo, Jesus D. (Department: 3617)
Ships
Boats, boat component, or attachment
Inflatable
C441S040000
Reexamination Certificate
active
06209476
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to improvements made to pneumatic boats comprising a generally U-shaped float open towards the rear and formed by at least one pneumatically inflatable tube, the rear ends of which are braced by a rear board, a rigid floor being disposed at least transversely inside the float, and a V-shaped hull made from a flexible canvas fixed to the float and to the rear board and held taut by a longitudinal inflatable keel inserted between said floor and said canvas.
DESCRIPTION OF THE PRIOR ART
So designed pneumatic boats are already known for example from documents FR 1 155 376, FR 2 510 064 and FR 2 734 234.
Using an inflatable keel offers an advantage over solid keels (made from wood for example) because of the light weight and the ease with which the deflated, folded pneumatic boat can be stored and transported.
However, the inflatable keels currently used have an inherent disadvantage in the way they are made. Inflatable keels are made in the form of an inflatable tube with an approximately circular cross section of a changing diameter which imparts a required specific longitudinal shape to the keel (see
FIGS. 7 and 7
a
of document FR 1 155 376).
The disadvantages resulting from this design are as follows:
a) a bow height (determined by the front part of the keel) which is necessarily reduced in order to avoid having to use a keel with a tube of too large a diameter which would require a large volume of gas for inflation purposes, and
b) a bow which is increasingly less streamlined the larger is the diameter of the tube used for the keel.
In practice, therefore, it is necessary to find a compromise when determining the diameter of the inflatable tube used for the inflatable keel whereby the diameter must be large enough to carry a high enough bow to impart a satisfactory heading hold to the craft but which at the same time must be as small as possible so that the bow remains sufficiently streamlined to fulfil its navigation function satisfactorily when contending with waves and so that the volume of gas needed to inflate it is not excessive.
Finally, there is another disadvantage inherent in the relatively low inflation pressure of the tube forming the keel (this pressure generally being the same as that used for buoyancy tube) which does not make the keel rigid enough, relatively speaking.
It should be pointed out at this point that solid keels, made from wood for example, do not have any of the disadvantages mentioned above in connection with inflatable keels since they can be designed to produce the requisite height and bow streamlining and are intrinsically rigid. On the other hand, they have the particular disadvantage of being heavy and cumbersome: they are generally made in a single piece of an elongate shape which makes storage difficult when the boat is deflated and folded ready for transportation or storage.
SUMMARY OF THE INVENTION
Accordingly, an object of the invention is substantially to propose an original technical solution which will combine the respective advantages of solid and inflatable keels whilst avoiding their respective disadvantages and to do so without incurring excessive additional cost.
With this aim in view, the invention proposes a pneumatic boat as above mentioned in the preamble, which is characterised in that the inflatable keel is made from an elongate enclosure delimited by two approximately parallel main walls extending longitudinally and approximately perpendicular to the floor, these walls being braced by a plurality of flexible links, and in that this enclosure is inflated to a relatively high pressure.
Advantageously, the inflatable enclosure is of a flat, plate-type shape, its thickness being very much smaller than its height and its length.
The bottom edge of the inflatable enclosure can be arranged so that it is curved, and in particular that the height of said enclosure increases very rapidly from the front end so as to define a bow, after which it decreases gradually towards the rear end, and the maximum height of the enclosure in the vicinity of the front end is relatively big so as to impart to the tautened canvas the shape of a streamlined bow with a relatively closed V-shape so that the hull is of a shape which is suitable for handling optimum conditions of navigability.
As a result of the features proposed by the invention, a pneumatic keel is provided which offers the advantages of a conventional inflatable keel (lightness, small volume and low space requirement in the non-inflated state, and is easy to fold up with the rest of the boat) whilst at the same time, because it is inflated to a high pressure, having the advantages of a conventional solid keel, made from wood for example (rigidity, streamlining, height at the front end, optimum bow design).
In some types of pneumatic boats, the floor may be provided as a pneumatic floor in the form of a flat pocket delimited by two approximately parallel main walls braced by a plurality of flexible links, this pocket being inflated to a relatively high pressure, whilst the inflatable enclosure forming the keel is joined longitudinally and axially to the bottom face of said floor so as to form a single piece with a T-shaped cross section.
It would also be conceivable for the hull to be formed, at least in the vicinity of the tip of the V, by at least one flat pocket with a flat V-shaped cross section, inflated to a relatively high pressure, and to join the inflatable enclosure forming the keel longitudinally and axially to the top face of said V-shaped pocket so as to form a single unit.
In either case, it is of advantage if there is a pneumatic communication between the inflatable floor and/or the V-shaped pocket of the hull on the one hand and the inflatable enclosure forming the keel on the other, and if the single unit is fitted with a single valve so that the floor and/or the V-shaped pocket of the hull can be inflated at the same time as the keel.
In one specific embodiment, which is preferred because of the easy steps by which the component parts can be manufactured, in which the inflatable enclosure defining the keel has a longitudinal pinched portion delimiting two communicating chambers located on either side of said pinched portion, this enclosure can be folded along this pinched portion so that the two chambers extend at approximately 90° relative to one another in the inflated state; in such a case stiffening means are provided to join the external walls of these two folded chambers so that they are held more or less perpendicular to one another in the inflated state, one of these chambers forming a base, being joined to the top face of the rubber floor, whilst the other chamber extends substantially perpendicular thereto, forming said keel, which is inflated to a relatively high pressure; advantageously in such a case, a permanent communication is provided between the rubber floor and said chamber forming a base joined thereto.
REFERENCES:
patent: 2698020 (1954-12-01), Phane
patent: 5152018 (1992-10-01), Lea
patent: 5642685 (1997-07-01), Garnier
patent: 5868095 (1999-02-01), Zeromski et al.
patent: 3205512 (1982-10-01), None
patent: 3603538 (1986-02-01), None
patent: 0693429 (1996-01-01), None
patent: 1155376 (1958-04-01), None
patent: 2230814 (1974-12-01), None
patent: 2463046 (1981-02-01), None
patent: 2760717 (1998-09-01), None
patent: 2765855 (1999-01-01), None
patent: 2168932 (1986-07-01), None
Maurel Didier
Zeromski Dominique
Kirkpatrick & Stockton LLP
Russell Dean W.
Sotelo Jesus D.
Zodiac International
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