Abstract:
A telescopic gangway ( 10 ) for boats ( 12 ) with a simplified construction, of the type comprising at least two portions ( 30, 50 ) telescopically foldable, in which a second portion ( 50 ) slides inside at least a first portion ( 30 ) of the gangway ( 10 ), in a longitudinal direction thereto, wherein said second portion ( 50 ) is equipped with a central supporting structure ( 52 ), which slides on another central supporting structure ( 32 ) of the first portion ( 30 ); these two central structures ( 30, 50 ) are equipped with reciprocal sliding guides ( 60 ) and longitudinal appendages ( 40 ) complementary to these.

Description:
The present invention relates to a telescopic gangway for boats with a simplified construction. 
     Landing gangways occupy an important position among nautical accessories. 
     They are used to allow easy passage between boats and piers. 
     FIELD OF THE INVENTION 
     They generally have a rectangular flat surface, wide enough to allow a person to cross and long enough to allow the boat to be moored to the pier at a safe distance. 
     BACKGROUND OF THE INVENTION 
     There are numerous types of construction and materials used. 
     There are manual and automatic gangways, depending on whether they are positioned between the boat and pier manually or with movements obtained by hydraulic cylinders. 
     The choice of materials derives from technical and aesthetic considerations, respecting functional demands. Polished AISI 316 stainless steel, stainless steel painted with epoxy products, light corrosion-resistant alloys with various degrees of surface finishing, temperate crystals, teak and technological polymers, are therefore used. 
     To complete the gangway, vertical rods, called stanchions in nautical terminology, connected by ropes, which help and support people crossing the gangway, can also be included on at least one side of the gangway. 
     Furthermore there may also be a swivel joint at one end of the gangway, connected to the boat, to allow the gangway to be lifted or rotated for positioning it on the boat when sailing. 
     Telescopically foldable gangways, generally automatic, are particularly used, especially due to the fact that they require minimum space on the boat. 
     These gangways are formed by subdividing the total walking length into two or more pre-established length portions. These portions are so formed that one or more of them can be inserted into another portion or into other nearby portions. 
     In this way, in the case of a telescopic gangway with two portions, the possibility of overlaping the two elements considerably reduces the amount of space during sailing. 
     In some cases, they are completely foldable which means that, when telescopically inserted, they can be fitted into appropriate housings built into the boats. 
     The known construction technique is to include, on each portion of the gangway, on each side, a tubular element which can be telescopically inserted into that of the adjacent portion. 
     Furthermore, these elements also have a supporting function as they sustain a central footboard which can be crossed by a person. 
     This system, however, makes the telescopic gangway rather heavy and this creates various disadvantages. 
     For example, as the gangway is generally carried by the boat during sailing, its weight is added to the total weight of the boat. 
     In addition, as the moving of the gangway requires the use of cylinders whose size depends on its weight, these cylinders will have characteristics and costs of a certain significance. 
     An objective of the present invention is therefore to overcome the above drawbacks and in particular to produce a telescopic gangway for boats with a simplified construction and limited weight. 
     Another objective of the present invention is to produce a telescopic gangway for boats, having an essentially light structure and an opening mechanism which is easy to use. 
     SUMMARY OF THE INVENTION 
     Yet another objective of the present invention is to create a telescopic gangway for boats with a simplified construction, which is particularly reliable, simple, functional and at relatively low costs. 
     These and other objectives according to the present invention are achieved by the production of a telescopic gangway for boats with a simplified construction as described in claim  1 . 
     Further characteristics are illustrated in the subsequent claims. 
     The characteristics and advantages of a telescopic gangway for boats with a simplified construction, according to the present invention, can be clearly understood from the following illustrative and non-limiting description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an axonometric view of a telescopic gangway for boats with a simplified construction, according to the present invention, connected to a boat; 
     FIG. 2 is an axonometric view of the telescopic gangway alone of FIG. 1, where the two telescopic portions are clearly visible; 
     FIG. 3 is a transversal section of the gangway of FIG. 2; 
     FIG. 4 is a partial enlargement of the transversal section of FIG. 3, showing the relative sliding elements between the two telescopic portions; 
     FIG. 4 a  is an axonometric view, which shows the same relative sliding elements between the two telescopic portions of which a section is already shown in FIG. 4; 
     FIG. 5 is a blow-up of the section of FIG.  4 . 
    
    
     With reference to the figures, these show a telescopic gangway for boats with a simplified construction, indicated as a whole with  10 , which can be used for the mooring of a boat  12  to a quay or jetty for disembarkation or boarding, and/or the haulage of tenders or water-scooters. 
     This connection is such that the gangway  10  can be rotated into a rest position, by means of a cylindrical pin  14  which runs through a hole  16 , situated at the end of the gangway  10 , and whose fulcrum is in correspondence with a “U”-shaped clamp  20 , fixed to the boat  12 . 
     DETAILED DESCRIPTION OF THE INVENTION 
     The rotation of the gangway  10  around the axis of the pin  14 , enabling it to be arranged in a rest or functioning position respectively, is effected by means of a hydraulic cylinder  22 , rotatingly fixed at its first end  24  to the boat  12 , under the clamp  20 , and at its second end  26 , opposite to the first, to the gangway  10 . 
     The gangway  10  in the example illustrated, according to the present invention, essentially comprises a first portion  30  and a second portion  50 , telescopically foldable, in the sense that it can slide along one of its longitudinal axes and can be inserted into this first portion  30 . 
     As can be clearly seen in FIG. 5, the first portion  30  has a first central structure  32 , effected by means of an overturned “U”-shaped draw piece, with an upper rectangular base  34  and two lateral portions  36 , symmetrical to each other and perpendicular to the base  34 . 
     Along each lateral portion  36 , close to a lower free end  37 , the central structure  32  has an extension  38 , orthogonal to the lateral portion  36  itself, and outside the central structure  32 . 
     This extension  38  is then refolded at the free end towards the base  34  of the structure  32 , creating a longitudinal channel  39 . 
     At the side of each portion  36 , and outside the structure  32 , there is a longitudinal appendage  40 , with three identical semicircular housings  41 ,  42  and  43 . More specifically, there is a lateral housing  41 , an upper housing  42  and a housing  43 , opposite to the housing  42 . 
     From FIG. 5 it can also be deduced that the second portion  50  of the gangway  10  has a second central structure  52 , effected by means of an overturned “U”-shaped draw piece, with an upper rectangular base  54  and two lateral portions  56 , symmetrical to each other and perpendicular to the base  54 . 
     Along each lateral portion  56 , close to a lower free end  57 , the central structure  52  has an extension  58 , orthogonal to the lateral portion  56  itself, and inside the central structure  52 . 
     This extension  58  thus forms, with the lateral portion  56  and the base  54 , a longitudinal guide  60 . 
     As can be seen in FIGS. 4 and 4 a , this guide  60  is complementary to the longitudinal appendage  40  of the first portion  30 , after the insertion of three reciprocal sliding cylinders or bearings or rods or plugs or bushings  62 , for example made of Delrin®, nylon, Teflon® or plastic material in general. 
     Along each lateral portion  56 , close to a lower free end  57 , the central structure  52  has an extension  59 , orthogonal to the lateral portion  56  itself, and outside the central structure  52 . 
     Furthermore, above the base  54  there is a series of “T”-shaped anchorages. 
     As can be seen in particular from FIG. 3, the walking area of the gangway  10  is produced by lining the second central structure  52  with a covering  66 , preferably made of fiberglass or plastic material, and lining the first central structure  32  with a covering  46 , again preferably made of fiberglass or plastic material; this assembly allows adequate insertion of the covering  66  inside the structure  46 , when the central portion  52  slides outside the structure  32  during the telescopic opening/closing movement of the gangway  10 . 
     More specifically, as the covering  66  has an essentially rectangular sectional structure and is open in a lower central zone where it ends in correspondence with the extensions  59 , it covers the top of the base  54  of the structure  52 , internally enveloping the anchorages  64 , which allow a firm hold between the structure  52  and covering  66 . 
     The covering  46  also has an essentially rectangular sectional structure, open in a central lower zone terminating in correspondence with the longitudinal channels  39  of the portion  32 ; its size is such as to encircle the covering  66  and the structure  52 , when this is inserted outside the structure  32 . 
     The functioning of the telescopic gangway for boats with a simplified construction according to the invention is clear from the description and is basically as follows. 
     During sailing, the second portion  50  of the gangway is telescopically inserted into the first portion  30 . Furthermore, the gangway  10  is kept in a raised position generally by means of the extension of the cylinder  22 . 
     When the boat  12  has been moored, the cylinder  22 , whose end  26  is fixed to the first portion  30  of the gangway  10 , is withdrawn until it is correctly inclined with respect to the mooring quay or jetty. 
     At this stage, the second portion  50  of the gangway  10  is extracted, also partially, as required, generally using another hydraulic cylinder, positioned according to a longitudinal axis of the gangway  10 . The purpose of this other cylinder is to ensure the reciprocal sliding of the two portions  30  and  50  of the gangway  10 . 
     This reciprocal sliding is effected thanks to the presence of the cylinders  62 , for example made of nylon, of which there are three in the non-limiting example shown in FIG.  3 . They are fixed to the housings  41 ,  42  and  43  of the longitudinal appendage  40 , against opposite walls of the guide  60 . 
     It should be pointed out that the number of cylinders  62 , and correspondingly the number of housings  41 ,  42  and  43 , may vary as required. 
     The characteristics of the telescopic gangway for boats, with a simplified construction, object of the present invention, are evident from the description, as also the relative advantages, among which: 
     simple and reliable use; 
     limited weight, consequently also with movement-activating devices having reduced weights and costs; 
     simplified construction, with reduced costs with respect to the known art, using materials such as fiberglass for the coverings and draw-pieces made of light alloy for the supporting structures. 
     Finally, numerous modifications and variations can obviously be applied to the telescopic gangway for boats, with a simplified construction, thus conceived, all included in the invention; furthermore all the details can be substituted by technically equivalent elements. In practice, the materials used, as well as the forms and dimensions, can vary according to technical demands. 
     The scope of protection of the invention is therefore defined by the enclosed claims.