DESCRIPTION

FIELD OF APPLICATION

[0001] The subj ect of the present invention is a propulsion device with a paddlewheel impeller for a vessel .

[0002] The present invention therefore refers to the field of propulsion systems for vessels .

PRIOR ART

[0003] To date , a variety of propulsion devices for vessels are known .

[0004] In particular, so-called hel ical devices , which are equipped with a hydraulic impeller with paddles proj ecting radially with respect to the rotation axis and having a helical profile , are in common use . The thrust direction of these helical devices is parallel to the axis of rotation of said helix .

[0005] Paddlewheel propulsion systems are also known .

[0006] These propulsion systems have a plurality of flat paddles arranged in a radial pattern relative to the rotation axis and extend along radial planes relative thereto . The thrust direction of these paddlewheel devices is perpendicular to the rotation axis of the wheel .

[0007] In these propulsion systems the paddles are mounted fixed relative to the structure of the impeller . This makes the propulsion system mechanically stronger and more reliable .

[0008] The fixed paddle configuration, however, involves a signi ficant operational limit . In the rotational movement of the impeller, the paddles that exceed the point of maximum immersion and rise towards the surface do not generate propulsive thrust and oppose the rotational motion of the wheel , taking power away from the motor . This signi ficantly reduces the efficiency of the propulsion system .

[0009] This behavior also imposes limits on the si ze of the paddles . The paddles , in fact , may not exceed certain dimensions in order not to further accentuate this dissipative phenomenon .

[0010] The limits to the surface extension of the paddles , however, inevitably translate into a limitation of the motor power trans formed by the paddles into propulsive thrust . The reduction of the dischargeable power may be partially compensated for by increasing the number of paddles . However, this entails design complications , linked to the si ze limits of the impellers .

[0011] These limits have been partially overcome by propulsion systems with orientable paddles . In this type of propulsion system, the paddles are all connected to a single eccentric rotation system which, depending on the angular position of the paddle , determines a di f ferent orientation thereof .

[0012] This solution, while improving propulsion ef ficiency, is however not altogether satis factory, since , in addition to being mechanically complex, it requires the paddles to continuously vary their orientation . This never allows for the paddles to be exploited in the active propulsion phase , nor for the friction of the paddles to be minimi zed in the passive propulsion phase .

[0013] Therefore , the need to have propulsion systems with paddlewheel impellers that have an increased propulsion ef ficiency and are at the same time easy to construct is still very much felt in the field of propulsion systems for vessels .

DISCLOSURE OF THE INVENTION

[0014] Therefore , the main obj ect of the present invention is to eliminate , or at least mitigate , the drawbacks of the aforementioned prior art , by providing a propulsion device with a paddlewheel impeller for a vessel that allows the propulsion ef ficiency to be increased signi ficantly .

[0015] A further obj ect of the present invention is to provide a propulsion device with a paddlewheel impeller for a vessel which is at the same time mechanically reliable .

[0016] A further obj ect of the present invention is to provide a propulsion device with a paddlewheel impeller for a vessel which is at the same time constructionally simple to produce .

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The technical features of the invention, according to the aforesaid obj ects , may be clearly seen in the contents of the claims below, and its advantages will become more readily apparent in the detailed description that follows , made with reference to the accompanying drawings , which represent one or more purely exempli fying and non-limiting embodiments thereof , wherein :

[0018] - Fig . 1 is a side orthogonal view of a paddlewheel propulsion device for a vessel according to a preferred embodiment of the invention;

[0019] - Fig . 2 is a perspective view from above of the propulsion device in Fig . 1 ;

[0020] - Fig . 3a, 3b, 3c and 3d show in sequence the operation of the device in Fig . 1 , schematically illustrated with a single pair of paddles to better highlight its functionality;

[0021] - Fig . 4a and 4b are , respectively, a perspective view and an orthogonal view of the propulsion device of Fig. 3 with a pair of paddles in which a first paddle is in an active (open) position and a second paddle is in a passive (closed) position; and

[0022] - Fig. 5a and 5b are, respectively, a perspective view and an orthogonal view of the propulsion device of Fig. 4a and 4b in which the two paddles of the pair are in inverted positions; and

[0023] - Fig. 6 is a detail of Fig. 4b relating to a paddle in the active (open) position;

[0024] - Fig. 7 is the same detail as Fig. 6 in which the paddle is in the passive (closed) position;

[0025] - Fig. 8 is an exploded view of a motorized impeller of a propulsion device according to a preferred embodiment of the invention, for illustrative reasons the impeller being shown without paddles;

[0026] - Fig. 9 is an orthogonal view of the impeller of Fig. 8, according to the arrow IX shown therein;

[0027] - Fig. 10 and 11 are two different orthogonal views of the motorized impeller of Fig. 8 in cross-section;

[0028] - Fig. 12 is a detailed perspective view of a propulsion device according to the invention illustrated with two paddles in a passive position; and

[0029] - Fig. 13 is a perspective view of the propulsion device of Fig. 12, illustrated with a paddle in an active position . [0030] Elements or parts of elements common to the embodiments described hereinafter will be indicated with the same numerical references .

DETAILED DESCRIPTION

[0031] The present invention relates to a propulsion device with a paddlewheel impeller for a ves sel .

[0032] The propulsion device with a paddlewheel impeller for a vessel according to the invention has been indicated collectively as 1 in the attached figures .

[0033] Here and in the fol lowing description and claims , reference will be made to the propulsion device 1 in the condition of use , i . e . , arranged in water . Therefore , any references to a lower or upper position or to a hori zontal or vertical orientation should be interpreted in this sense .

[0034] According to a general embodiment of the invention, the propulsion device 1 comprises a support frame 10 , which may be attached to a hull of a vessel , and a motori zed paddlewheel impeller 20 supported by said frame 10 .

[0035] The frame 10 may have any shape as long as it allows it to support the impeller in rotation . In Fig . 1 and 2 , the support frame 10 is shown schematically, for example , as a fork body, which supports the impeller 20 at its two axial ends between the two arms of the fork and is intended to be connected to a vessel at the base of the fork .

[0036] In turn, the paddlewheel impeller 20 comprises :

[0037] - an impeller body 21 , rotationally supported by a rotation pin 11 of said frame 10 about a rotation axis X ; and

[0038] - a plurality of orientable paddles 30 ' , 30" .

[0039] Each of said orientable paddles 30 ' , 30" is movably associated with the aforesaid impeller body 21 so as to move in a guided manner during rotation of the impeller between

[0040] - an active position, in which the paddle 30 ' , 30" protrudes relative to the impeller body 21 , and

[0041] - a passive position, in which the paddle protrudes relative to the impeller body 21 less than in the active position .

[0042] As illustrated in the sequence of Fig . 3a, 3b, 3c and 3d, the device 1 is designed to be partially immersed in water in use with a waterline G passing near the rotation axis X . In this way, during the rotation of the impeller, each paddle 30 ' , 30" will alternate between immersion and surfacing .

[0043] Operationally, the rotational motion of the impeller 20 is trans formed into propulsive thrust by the paddles 30 ' , 30" , which periodically during the rotation of the impeller are in the active position and immersed in water . As will be made clear later in the description, each paddle , in the course of rotation of the impeller, periodically moves between the active position (where it may exert propulsive thrust ) and the passive position (where the paddle does not exert propulsive thrust ) .

[0044] According to the invention, the aforesaid impeller body is defined by a cylindrical body 21 with a circular cross-section, extending in length coaxially to said rotation axis X between two bases 21a, 21b connected by a cylindrical lateral surface 21c .

[0045] As illustrated in particular in Fig . 1 and 2 , each paddle 30 ' , 30" is hinged to the impeller body 21 externally thereto near the cylindrical lateral surface 21c of the cylindrical body along a hinge axis Y parallel to the rotation axis X to move between said passive position and said active position .

[0046] The paddles 30 ' , 30" are then configured and associated with the impeller body 21 so that they are always arranged completely outside the cylindrical body that defines the impeller body 21 .

[0047] According to the invention, the aforesaid orientable paddles 30 ' , 30" are even in number and are distributed about the cylindrical lateral surface 21c of the cylindrical body in pairs of paddles hinged in positions diametrically opposite to each other .

[0048] A paddle 30 ' of each pair of paddles is kinematically connected to the diametrically opposite paddle 30" by means of a connecting rod 40 . Functionally, the connecting rod 40 is configured to kinematically synchroni ze the opening movement of one paddle 30 ' from the passive position to the active position with the opposite closing movement of the other paddle 30" from the active position to the passive position .

[0049] Operationally, each paddle may be hinged to the impeller body so as to have two opposite opening rotation directions . I f the impeller 20 is made to rotate about the rotation axis X in the rotation direction corresponding to the opening rotation direction of the paddle , the very rotation of the impeller naturally causes the paddle to open ( switch from the passive position to the active position) upon immersion of the paddle in water due to the pressure of the water infiltrating between the paddle and the cylindrical lateral surface of the cylindrical body . I f it were left free , the paddle , once opened, would tend to remain in that position at least during the entire underwater rotation . In this way, past the point of maximum immersion, it would continue to counteract the rotation of the impeller, but without contributing to the propulsive thrust .

[0050] By virtue of the invention, and particularly by the fact that the paddles are kinematically connected two-by- two by means of at least one connecting rod so that they complete opposite opening and closing movements , thi s phenomenon of ef ficiency loss is signi ficantly reduced . In fact , the opening of one paddle synchronously determines the simultaneous closing of the paddle placed in the diametrically opposite position . Therefore , once the point of maximum immersion has been passed, before surfacing, the paddle is automatically retracted into closure by the opening movement of the opposite paddle that is in the meantime beginning to submerge . Thi s reduces the braking ef fect of immersed paddles that have passed the point of maximum immersion . Therefore , for the same amount of power applied in the rotation of the impeller, there is an increase in the ef ficiency of the propulsion device .

[0051] More speci fically, as illustrated in the sequence of Fig . 3a, 3b, 3c and 3d, with the impeller in rotation, as soon as one paddle begins to submerge in water, due to the pressure exerted by the water between the paddle and the cylindrical lateral surface , the paddle begins to open and generate propulsive thrust ; at the same time the opening motion of this paddle triggers ( due to the action of the connecting rod) an opposite closing motion of the diametrically opposite paddle; said latter paddle, when it is still fully immersed but after it has passed the point of maximum immersion (thus after it has exhausted its thrust capacity, see Fig. 3b) , begins to close, opposing less and less the rotation of the impeller.

[0052] Thus, the propulsion device with a paddlewheel impeller for a vessel according to the invention allows for a significant increase in propulsion efficiency. This increase in efficiency is also achieved in a mechanically simple and reliable way.

[0053] Preferably, as illustrated, for example, in Fig. 4a- b and 5a-b, in the passive position, the paddle 30' , 30" has approached the lateral surface 21c of the cylindrical body forming the impeller body 21 so as to minimize its fluid-dynamic resistance, while in the active position the paddle 30' , 30" has been moved away from the lateral surface 21c of the cylindrical body 21 so as to maximize its fluid-dynamic resistance and thus its thrust capacity .

[0054] Advantageously, each of said orientable paddles 30' , 30" has a curved profile. Preferably, the curved profile of said orientable paddles 30' , 30" corresponds to the outer profile of the cylindrical lateral surface 21c of the cylindrical body 21. Thus, when brought into the passive position, the paddles 30 ' , 30" may better approach the cylindrical lateral surface and thus reduce their fluid dynamic resistance .

[0055] Preferably, each paddle 30 ' , 30" is configured such that :

[0056] - when the paddle is in the active position, there is no clearance between the paddle 30 ' , 30" and the cylindrical lateral surface 21c parallel to the hinge axis Y so as to prevent in use a flow of water between the paddle and the cylindrical lateral surface 21c ;

[0057] - when the paddle 30 ' , 30" is in the passive position or intermediate positions between the active and passive positions , parallel to the hinge axis Y, there is clearance between the paddle 30 ' , 30" and the cylindrical lateral surface 21c so as to allow in use a flow of water between the paddle and cylindrical lateral surface 21c .

[0058] In this way, when the paddle 30 ' , 30" is in the active position and is generating thrust , power losses due to pressure releases are reduced; however, as soon as the paddle leaves the active position to move toward the passive position, the water collected between the open paddle and the impeller body may immediately begin to discharge through the slit that has opened between the paddle and the cylindrical lateral surface . This not only prevents water retained by the paddle from hindering the closing of said paddle , but said flow generated through the slit facilitates its closing movement . This helps to increase the ef ficiency of the system .

[0059] Preferably, each paddle 30 ' , 30" is hinged to the impeller body 21 by means of mechanical transmission means 36 that are adapted to rotate the paddle eccentrically about the hinge axis Y along a rotation edge 32 of said paddle in the transition between said passive position and said active position .

[0060] Speci fically, as illustrated in Fig . 6 and 7 , the aforesaid mechanical transmiss ion means 36 are configured in such a way that in said active position the rotation edge 32 of the paddle 30 ' , 30" is in contact with the cylindrical lateral surface 21c ( see Fig . 6 ) , while in the passive position, or in intermediate positions between said active and passive positions , the rotation edge 32 of the paddle 30 ' , 30" is distanced from the cylindrical lateral surface 21c so as to create a slit 35 between the paddle 30 ' , 30" and lateral surface 21c ( see Fig . 7 ) .

[0061] Advantageously, due to the eccentric rotation about the hinge axis Y, the distance between the paddle and cylindrical lateral surface is variable in the transition between active and passive positions . In this way, the slit 35 that is opened parallel to the hinge axis Y has a variable clearance that gradually increases until it reaches the passive position .

[0062] According to an embodiment shown in Fig . 1 to 7 , the aforesaid mechanical transmission means 36 comprise at least one connecting rod 36 between the paddle 30 ' , 30" and the impeller body 21 .

[0063] According to an alternative embodiment , shown in Fig . 12 and 13 , each paddle 30 ' , 30" may be hinged directly to the impeller body 21 without interposition of mechanical transmission means . Thus , in the transition between said passive position and said active position 36 , the paddle 30 ' , 30" rotates concentrically about the hinge axis Y, without varying the distance between the rotation edge 32 of the paddle and the cylindrical lateral surface 21c .

[0064] Preferably, as shown in Fig . 6 and 7 and Fig . 12 and 13 , each paddle 30 ' , 30" is hinged to the impeller body 21 at portions of the bases 21a and 21b of the cylindrical body that protrude radially from the cylindrical lateral surface 21c .

[0065] Advantageously, each paddle 30 ' , 30" may be equipped with a plurality of through openings 34 suitable for allowing the continuous passage of water regardless of the position assumed by the paddle . These through openings 34 allow for a continuous discharge of water pressure between the paddle and cylindrical lateral surface . These through openings 34 may be made as an alternative to or in combination with the presence of the slit 35 with variable clearance provided between the paddle and cylindrical lateral surface 21c .

[0066] Preferably, as illustrated in the attached figures , each paddle 30 ' , 30" may comprise a plurality of appendages 33 extending from a free edge 31 of said paddle opposite a rotation edge 32 of said paddle and diverging outwardly with respect to said paddle . Functionally, said protruding appendages 33 increase the fluid dynamic resistance of the paddle when it is in the passive position . Operationally, when the paddle is in the passive position and about to submerge ( during rotation of the impeller ) , the first portions of the paddle to enter the water are the protruding appendages 33 . Due to their divergent shape , they create resistance to entering the water by leading to an increase in pressure locally that facilitates the movement of the paddle from the passive position and thus the opening of the paddle . This helps to increase the overall ef ficiency of the system .

[0067] According to a preferred embodiment illustrated in Fig . 1 and 2 , the paddles of a first set of pairs of paddles are oriented to open by rotating in a first direction, and the paddles of a second set of pairs of paddles are oriented to open by rotating in a direction opposite to the first .

[0068] Thus , operationally, depending on the direction of rotation of the impeller body 21 ( clockwise or counterclockwise ) , either the paddles of the first set of pairs of paddles or the paddles of the second set of pairs of paddles are activated (periodically opening and closing) . The paddles that are not activated by the rotation of the impeller body assume an intermediate equilibrium position between the active and passive positions .

[0069] The activation of one set of paddles relative to another results in the reversal of the direction of propulsion . Thus , with this paddle configuration it is possible to reverse the direction of propulsion by reversing the direction of rotation o f the impeller .

[0070] Preferably, as shown in Fig . 1 and 2 , the paddles of said first set are distributed alternately with the paddles of said second set about said lateral surface 21c . Thus , in use the device 1 is able to deliver evenly distributed propulsion during a full rotation of the impeller 20 .

[0071] According to an embodiment illustrated for example in Fig . 12 and 13 , all the paddles may be oriented to open by rotating in the same direction . In this case , the device 1 is able to deliver propulsion only in the direction of rotation of the impeller that causes the paddles to open . The advantage of this embodiment , relative to the embodiment with paddles with a di f ferentiated opening direction, lies in the fact that , for the same number of paddles and for the same applied power, there is greater propulsive thrust since twice as many paddles are active .

[0072] Preferably, the connecting rod 40 that kinematically connects the two paddles 30 ' , 30" of a pair of paddles together is arranged externally to the cylindrical body at one of the two bases 21a and 21b of the cylindrical body 21 .

[0073] Advantageously, as shown in the attached figures , the aforesaid connecting rod 40 defines a radially elongated slot 41 at which the connecting rod 40 rotationally and slidingly engages the rotation pin of said frame 10 . This makes it possible to arrange the connecting rod 40 outside the cylindrical body 21 , thus avoiding, in a mechanically simple way, interference between the connecting rod and the rotation pin .

[0074] Preferably, the two paddles of a pair of paddles are kinematically connected to each other by two connecting rods 40 : a first connecting rod is arranged at a first base 21a of the cylindrical body and connects the two paddles to each other at a first axial end; a second connecting rod is arranged at a second base 21b of the cylindrical body and connects the two paddles to each other at a second axial end, opposite to the first . The two-rod configuration allows for a more balanced distribution of stresses to be obtained when moving the two paddles .

[0075] According to a fully preferred embodiment of the invention, the cylindrical body forming the impeller body 21 delimits an internal watertight cavity 22 . Thus the impeller 20 is a floating body and does not need to be supported in buoyancy by the vessel with which the device 1 is associated .

[0076] Preferably, the device 1 comprises motor means 50 housed inside the aforesaid internal watertight cavity 22 . These motor means 50 are supported by said frame 10 within the watertight cavity and are kinematically connected to said impeller body 21 to bring it into rotation .

[0077] Preferably, said motor means 50 are of the electric type and may be powered by an electric battery and/or a photovoltaic system . Preferably, the battery and photovoltaic system are housed on board the vessel and are electrically connected to the motor means via electric cables that enter the watertight cavity by passing through the rotation pin of the impeller .

[0078] Fig . 8 , 9 , 10 and 11 show an example of connection between the electric motor means 50 and the impeller 20 .

[0079] More speci fically, the impeller body 21 consisting of the hollow cylindrical body is divided into two parts : a fixed part integral with the support frame 10 and the corresponding rotation pin 11 ; and a movable part , rotationally associated with the fixed part and free to rotate about the rotation axis defined by the pin 11 .

[0080] More speci fically, the fixed part is defined by two disks 23 , 24 that each define one of the two bases 21a, 21b of the cylindrical body and are coaxial with the rotation axis X . These two disks 23 , 24 are connected to each other by a plurality of connecting rods 25 . The rotationally movable part consists of a tubular body 26 with a circular cross-section that defines the cylindrical lateral surface 21c of the cylindrical body and is coaxial with the disks 23 , 24 and the axis X . The aforesaid tubular body 26 engages the two fixed disks 23 and 24 rotationally by means of two circular flanges 27 , 28 integral therewith . The motor means 50 comprise an electric motor 51 that is mechanically supported by the fixed part of the impeller body, e . g . , by the connecting rods 25 . The electric motor 50 is connected by means of a transmission system 52 to coupling means 53 adapted to couple to one of the two flanges 28 to impose thereon, and thus on the moving part , a rotational motion about the axis X .

[0081] The subj ect of the present invention is also to provide a vessel comprising a propulsion device with a paddle impeller, in which the aforesaid propulsion device is according to the invention and in particular as described above .

[0082] The invention allows numerous advantages to be obtained which have been explained throughout the description .

[0083] The propulsion device with a paddlewheel impeller for a vessel according to the invention allows for the propulsion ef ficiency to be signi ficantly increased relative to fixed paddle propulsion systems .

[0084] The propulsion device with a paddlewheel impeller for a vessel according to the invention is also both mechanically reliable and constructionally simple to make . In particular, the device according to the invention is easier to implement than traditional propulsion systems with orientable paddles .

[0085] The propulsion device with a paddlewheel impeller for a vessel according to the invention may also be constructed as a floating body, which in particular may contribute to the buoyancy of the vessel with which it is associated .

[0086] Due to the fact that the device according to the invention allows propulsion to be generated in a signi ficantly more ef ficient way, the impeller drive system does not require a great amount of power, and may therefore consist of electric motors powered by electric batteries and/or a photovoltaic system installed on board the vessel , for example .

[0087] The invention thus conceived therefore achieves its intended obj ects .

[0088] Obviously, in practice it may also assume di f ferent forms and configurations from the one illustrated above , without thereby departing from the present scope of protection .

[0089] Furthermore , all details may be replaced with technically equivalent elements , and the dimensions , shapes , and materials used may be any according to the needs .