DESCRIPTION This invention concerns a device for protection of a submerged element from marine vegetation, particularly for protection of a piston-cylinder assembly.

More in detail, this invention concerns a device to remarkably reduce the amount of marine vegetation, which can be encrusted in mechanical and/or hydraulic moving means of a craft, after a long standing for example in a port.

In the following the description will concern the protection of hydraulic means of a boat, but it is obvious that it have not to be considered limited to this specific employment.

It is known that if a craft is stood for example in a port, a layer of marine vegetation could grow on the surface of the stern assembly or on the screw, which tends to be encrusted. In case of the layer is very thick it can block the use of said mechanic means, which need to be descaled.

Moreover, the stern assemblies are characterised by hydraulic means, as the piston-cylinder assemblies. Inside them, between the piston and the cylinder, there are some oil gaskets, which are subject to pressure during the normal working. Following the growth of the marine vegetation on the piston, when it is activated after a long stop, said vegetation accumulates all around the gasket.

This implies a rapid wear of said gasket, and a following leak of oil.

Eliminating said encrustation layer manually is possible, for example by means of high pressure water nozzles, but this implies an high cost for the haulage and the launch of the boat. Moreover this procedure is very laborious and does not allow a careful cleaning.

Actually there are also in the market"anti-vegetative"liquid substances. Those ones have the advantage to be very affective, but they are not 100% biodegradable and thus can be polluting. Moreover, those substances does not adhere to secular surfaces, as the hydraulic piston rods.

It is an other solution, protecting said inner gaskets by means of rings provided with a blade placed at the entrance of the cylinder which scrape the surface of the moving piston. This solution has the main problem that the blade does not allow to clean the surface at a microscopic level, as can be obtained by means of the "anti-vegetative"substances. The wearing process of the gasket is only slowed down but not avoided. Thus the encrusted material accumulates around the gasket.

In view of the above, it is evident the necessity to have a system which does not allow, or at least slows down very much, the growth of marine vegetation on the mechanical parts of the boats, and particularly on the hydraulic devices submerged in the water, as the one proposed in this invention.

The solution according to this invention takes place in this context.

The object of the present invention is to avoid the growth of the marine vegetation on the mechanical and hydraulic parts of a craft, even following long standing for example in a port.

It is specific subject matter of this invention a device for protection of a submerged element from marine vegetation characterised in that said protection device protects the surface of said submerged element from the ambient light preventing the proliferation of marine vegetation and/or marine fauna.

Preferably according to the invention, said submerged element could be a piston-cylinder assembly, which could be of the type comprising at least a cylinder coupled to at least a piston and to oil pumping means, said cylinder comprising an entrance in which said piston can enter and at least a gasket placed inside said entrance, said gasket being in contact with the surface of said piston.

Always according to the invention, said protection device could be placed outside said entrance of said cylinder.

Preferably according to the invention, said device could be a sleeve preferably with a cylindrical shape and could cover only the maximum portion of said piston, which enters inside said cylinder.

Further according to the invention, said cylinder could comprise a cavity concentric to said entrance, such that it could be telescopic and it could comprise a hooking mean of its end to said

piston, said device being able to come in and/or out from said concentric cavity when the piston comes in and/or comes out from said cylinder.

Preferably according to the invention, said device could be realised by rubber and or by fiberglass and/or any stainless metal.

Still according to the invention, said cylinder could comprise hooking means of said piston-cylinder assembly to the hull of a boat which could comprise at least a cavity and/or holes for bolts.

Always according to the invention, said oil pumping means could comprise an electric motor and/or a combustion engine.

This invention will be now described, by way of explanation and not by way of limitation, according to its preferred embodiments, by particularly referring to the attached drawings, in which: figure 1 shows a perspective view of a hydraulic piston- cylinder assembly according to the present invention; figure 2 shows a side view of the hydraulic piston-cylinder assembly of figure 1; figure 3 shows a side section of the hydraulic piston-cylinder assembly of figure 1; and figure 4 shows a side section of a further embodiment of the hydraulic piston-cylinder assembly according to the present invention.

To understand better the present invention it is described in the following the functioning ways of the preferred embodiment of the piston-cylinder assembly according the present invention.

Referring to figures 1 and 2 it is possible to examine a piston-cylinder assembly 1, which comprises a cylinder 2 and a piston 3. On the cylinder 2 there are also coupling means 4 to couple said piston-cylinder assembly 1 to the hull of a boat.

At the end of the cylinder 2, where the piston 3 enters in the cylinder 2, there is a sleeve 5, which allows to cover a part of the length of the piston 3. The sleeve 5 is not watertight. It allows only the protection from light preferably of the maximum portion of the piston 3, which enters inside the cylinder 2.

It is observed that the marine vegetation does not grow, or anyway, much less without light. This happens even if the mechanic means are stood for very long periods. By means of the sleeve 5 the marine vegetation is prevented to grow in the part of the piston 3 that

enters in the cylinder 2, and that can thus be in contact with a gasket 6. Thus it is not necessary that the sleeve is watertight. It is only necessary that it allows the maximum covering of the light.

It is possible to see a further embodiment of a piston- cylinder assembly 1 according to the present invention in figure 4.

More in detail it is possible to see that at the ends of the sleeve 5, there are two rings 7 and 7', which show some blades, which scrape the surface of the piston 3. This allows protecting further the gasket 6. Indeed, if, in spite of the sleeve 5, some encrustations form on the surface of the piston 3, the blades 7 and 7'make a scraping during any movement of the piston 3, entering in the cylinder 2.

The sleeve 5 can be realised by different materials as rubber, aluminium, stainless steel.

On the basis of the previous description, the most important characteristic of the present invention is creating suitable devices, which allow protecting mechanical parts from light, to avoid the encrustations due to the growth of marine flora and/or marine vegetation in general.

An advantage of the present invention is that it is particularly favourable from the economic point of view.

Another advantage of the present invention is that it allows reducing a lot the maintenance of the hydraulic means and the replacement of the gaskets.

This invention have been above described by way of illustration, but not by way of limitation according to its preferred embodiments and it should be understood that those skilled in the art can make other modifications and changes without departing from the scope of the invention as defined in the following claims.