EP1970302B1

EP1970302B1 - Oscillating hydrofoil propulsion and steering system

Info

Publication number: EP1970302B1
Application number: EP20080075013
Authority: EP
Inventors: Paul Grima
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-03-13
Filing date: 2008-01-07
Publication date: 2012-11-21
Anticipated expiration: 2028-01-07
Also published as: EP1970302A1

Description

The present invention relates to an oscillating hydrofoil propulsion and steering system, which is provided in general for waterborne crafts.
Current propeller and cycloidal propulsion systems have many known drawbacks. Many propellers, indeed, lose efficiency at speed and, if not properly designed, can be damaged by cavitation. Moreover propellers have limits since they produce propeller walk, especially when reversing, and propeller slip, which diminishes their efficiency. Propellers are very noisy and cause a lot of vibrations, especially at speed, and can be heard at great distances under water. It is also known that, on motorized sailing vessels, propellers cause undesired drag when the vessel is sailing, even if they are feathered. On the other hand, cycloidal propulsion systems can reach very limited speed.
Further propeller and cycloidal propulsion systems, provided on different waterborne crafts, can be lethal to swimmers and aquatic life due to the blade rotation under water. It is therefore imperative to switch their engines off, for example, during rescue operations. Propeller and cycloidal propulsion systems are also very vulnerable to hitting hard objects.
These drawbacks force some waterborne military vessels to a limited speed in stealth missions, and makes it hard to study some forms of marine life closely without disturbing the same.
Document US 2004/195440 A1 discloses an invention which imitates the thuniform movement of a fish's tail in which two hydrofoil blades are fitted into each pod (if so equipped). The said hydrofoil blades are made to converge and diverge in a linear motion for propulsion. The pod (if so equipped) is used solely for steering only. The inventor only suggest how the motor transmits drive to the hydrofoil blades.
Document US 2,085,307 A discloses an invention in which a reed valve mechanism is reciprocated in the water in order to propel, and rotated so as to steer the vessel. Such mechanism has a very limited speed and maneuverability, can be quite bulky, moves in pulses, and generates noise every time the reed valves snap closed.
Document FR 2 306 874 A discloses an invention in which vanes are made to rotate in a dedicated duct to provide forward or reverse thrust depending on the direction of rotation of the propeller shaft. This invention can be quite bulky, produces many noises and vibration by way of the vanes hitting the duct sides, and can be lethal to swimmers and aquatic life. The said invention cannot perform steering unless the whole duct is rotated or is fitted with an additional rudder. Such mechanism has a very limited speed and maneuverability.
Document FR 2 470 875 A discloses an invention in which two hydrofoil blades are fitted into a duct and made to oscillate. The said invention cannot perform steering or reverse thrust unless the whole duct is rotated or is fitted with an additional rudder. This invention can be quite bulky, produces many noises and vibrations by way of the hydrofoil blades hitting each other and the duct sides, and can be lethal to swimmers and aquatic life. Such mechanism has a very limited speed and maneuverability.
Document GB 541 775 A discloses an invention in which hydrofoil blades imitate the thuniform movement of a fish's tail, in which hydrofoil blades are made to oscillate in different embodiments. The angle of attack of said hydrofoil blades and the rate of oscillation cannot be varied. Not all embodiments of said invention are designed to neutralize torque, and no flap damping mechanism is shown, resulting in an uncomfortable pulsed ride. The said invention cannot perform steering or reverse thrust in most of the embodiments unless it is fitted with an additional rudder.
Document FR 1 330 218 A discloses an invention in which hydrofoil blades imitate the thuniform movement of a fish's tail. Said hydrofoil blades are slideably fitted into a channel and made to oscillate. The thuniform movement is achieved by connecting the said hydrofoil blades to a crank. The angle of attack of said hydrofoil blades and the rate of oscillation cannot be varied. No flap mechanism damping is designed. The said invention cannot perform steering unless it is fitted with an additional rudder. Such mechanism has a very limited speed and maneuverability.
Document WO 02/055381 A discloses an invention in which one or more hydrofoil blades imitate the thuniform movement of a fish's tail. Said hydrofoil blades are oscillated by pedal power to propel the vessel. In some of the embodiments only the down stroke produces thrust since the hydrofoil blade trails idly on the up stroke. The angle of attack of said hydrofoil blades cannot be varied on some of the embodiments. The said invention cannot perform steering unless it is fitted with an additional rudder. The said invention has a very limited speed and maneuverability. Not all said embodiments are designed to neutralize torque, resulting in an uncomfortable pulsed ride.
The present invention also imitates the thuniform movement of a fish's tail. The present invention, however, invariably necessitates at least two casing. All casings perform both propulsion and steering. The casings can house at least one or more hydrofoil blades. Each two casings rotate synchronously in the same direction to steer the vessel to an angle from 0 to 360 degrees. Each two casings partially rotate in opposite directions synchronously in order to make the hydrofoil blades converge and diverge for propulsion. The hydrofoil blades are made to converge and diverge in a semicircular motion. The flap mechanism damping resistance and the angle of attack of the hydrofoil blades can both be variable. Power transmission and steering mechanisms in all embodiments are disclosed in detail. Power is transmitted directly to the connecting rods, arms, or casings by reciprocating driven rods. The present invention can be fitted in different embodiments to all kinds of craft, including pedal boats, stealth vessels, hydrofoil boats, submarines, and outboard motors. Most of the embodiments of this invention are simpler and more economically manufactured and maintained than prior art. The present invention is more efficient, smooth, virtually silent, more robust, can attain high speeds, and is fully maneuverable.
Main object of the present invention is, therefore, to provide a propulsion and steering system which makes vessels faster and more fuel-efficient than either cycloidal-driven vessels or most propeller vessel.
Further object of the present invention is to provide a propulsion and steering system which makes vessels much more maneuverable than either cycloidal vessels or propeller vessels, without need of any bow or stern thruster, since it is able to make a vessel turn 360 degrees on the same spot or even move sideways and backwards or in any other direction. Thus a submarine equipped with the propulsion and steering system according to the present invention can move sideways and/or up and down without any forward motion, even without its ballast tank operation, staying level, and always in quite complete silence, since it should be free from propeller noise and vibrations. For motorized sailing vessels the propulsion and steering system according to the present invention may serve, while sailing under wind power, as a keel and/or rudder system.
Further object of the present invention is to provide a propulsion and steering system which is much safer for swimmers and aquatic life than propeller and cycloidal system, thus allowing for studying aquatic life closely without disturbing the same since there is no propeller noise and vibrations.
Further object of the present invention is to provide a propulsion and steering system which is much more stealthy than prior art.
Further object of the present invention is to provide a propulsion and steering system which is much more robust than prior art.
Further object of the present invention is to provide a propulsion and steering system which does not result as vulnerable as propeller and cycloidal systems to hitting hard objects.
Further object of the present invention is to provide a propulsion and steering system which can be made weedless and/or tangle-free, by which a vessel can avoid being entangled in submerged weeds, ropes or nets.
The oscillating hydrofoil propulsion and steering system according to some embodiments of the present invention, contrary to prior art, can be used to manufacture fast and stealthy hydrofoil boats.
The oscillating hydrofoil propulsion and steering system according to the present invention, contrary to prior art, can be applied in different embodiments suitably on all kind of waterborne craft.
A detailed description of the oscillating hydrofoil propulsion and steering system according to some embodiments of the present invention will be now provided with reference of the annexed drawings in which:

fig. 1 is a top view of the oscillating hydrofoil propulsion and steering system according to a first embodiment of the present invention;
fig. 2 is a top view of the oscillating hydrofoil propulsion and steering system according to a second embodiment of the present invention;
fig. 2a is an exploded view of the oscillating hydrofoil propulsion and steering system in fig. 2;
fig. 3 is a top view of the oscillating hydrofoil propulsion and steering system according to a third embodiment of the present invention;
fig. 3a is a top view of the oscillating hydrofoil propulsion and steering system according to the embodiment in fig. 3 showing a first member displacement;
fig. 3b is a top view of the oscillating hydrofoil propulsion and steering system according to the embodiment in fig. 3 showing a second member displacement;
fig. 3c is a top view of the oscillating hydrofoil propulsion and steering system according to the embodiment in fig. 3 showing a third member displacement;
fig. 3d is a top view of the oscillating hydrofoil propulsion and steering system according to the embodiment in fig. 3 showing a fourth member displacement;
fig. 3e is a top view of the oscillating hydrofoil propulsion and steering system according to the embodiment in fig. 3 showing a fifth member displacement;
fig. 3f is a side view of the oscillating hydrofoil propulsion and steering system according to the embodiment in fig. 3;
fig. 3g is an exploded view of the oscillating hydrofoil propulsion and steering system in fig. 3;
fig. 4 is a top view of the oscillating hydrofoil propulsion and steering system according to a fourth embodiment of the present invention;
fig. 5 is a top view of the oscillating hydrofoil propulsion and steering system according to a fifth embodiment of the present invention;
fig. 5a is a top view of the oscillating hydrofoil propulsion and steering system according to the embodiment in fig. 5 showing the alternative member displacement;
fig. 6 is a top view of the oscillating hydrofoil propulsion and steering system according to a sixth embodiment of the present invention;
fig. 7 is a top view of the oscillating hydrofoil propulsion and steering system according to a seventh embodiment of the present invention;
fig. 8 is a perspective view of the oscillating hydrofoil propulsion and steering system according to the strut mounted embodiment of the present invention;
fig. 8a is an exploded view of the oscillating hydrofoil propulsion and steering system according to the embodiment in fig. 8;
fig. 8b is a side view of the oscillating hydrofoil propulsion and steering system according to the embodiment in fig. 8 showing a first member displacement;
fig. 8c is a side view of the oscillating hydrofoil propulsion and steering system according to the embodiment in fig. 8 showing a second member displacement;
fig. 8d is a side view of the oscillating hydrofoil propulsion and steering system according to the embodiment in fig. 8 showing a third member displacement;
fig. 8e is a side view of the oscillating hydrofoil propulsion and steering system according to the embodiment in fig. 8 showing a fourth member displacement;
figs. 9 to 9b show an arrangement of the strut mounted oscillating hydrofoil propulsion and steering system according to the embodiment in fig. 8 preferable for a hydrofoil boat;
figs. 10 to 10b show an arrangement of the oscillating hydrofoil propulsion and steering system according to the embodiment in fig. 8 preferable for a sailboat;
figs. 11 to 11b show an arrangement of the oscillating hydrofoil propulsion and steering system according to the embodiment in fig. 8 preferable for a submarine.

Referring now to fig. 1, a main drive unit (16) is shown, operatively connected to a pair of transmission housings (15), each gearing a casing (4). Each casing (4), in turn, has arranged thereon an hydrofoil blade (1) movably attached to a flap mechanism (3). Said casings (4) are preferably mounted flush to any submerged or submersible portion of the outer surface of vessel (see fig. 3f). In such embodiment both the propulsion transmission and the steering mechanism are combined into each housing (15), governed by said drive unit (16), that generates a motion of the pinion (4a), gearing the crown wheel (4b), oscillating whilst synchronously converging and diverging the hydrofoil blades (1) as they partially rotate for propulsion, and rotate synchronously in the same direction for steering, respectively.
In fig. 2 there is illustrated a second embodiment in which the propulsion transmission and the steering operation are realized by two different mechanisms. The mechanism for the propulsion transmission comprises a pair of connecting rods (7) and a pair of arms (5) gearing each other. Each connecting rod (7) is hinged to the corresponding arms (5) that, in turn, is hinged to a casing (4). The connecting rods (7) are preferably a hydraulic or pneumatic rams and provide synchronous reciprocating motion to the casings (4) by said pair of arms (5) through the endless screw (12) which gear the crown wheels (4b) on the said casings (4). The mechanism for steering, instead, comprises a shaft (11), a steering gearbox (8), a pair of telescopic shafts (9) and a pair of endless screws (12), each gearing the corresponding above described casing (4). The rotation of the shaft (11) is transmitted, through said steering box 8, to each telescopic shaft 9 that, in turn, rotates each endless screw 12, thus rotating the corresponding casing 4 synchronously in the same direction.
Further embodiment is illustrated in fig. 3 that shows a propulsion transmission system different in respect of the previous embodiment. Each of said arms 5 is hinged to a connecting rod 7, hinged, in turn, at the opposite end to a rod 13, by which the reciprocating motion is provided in order to generate the propulsion needed. Figs. 3a to 3f show different configurations of the propulsion and steering system assured by the above described embodiment. Fig. 3a shows the hydrofoil blades 1 flapping and rotating around their axis and the operation of the flap mechanism 3 that acts as damper. Fig. 3b shows the rotation of the hydrofoil blades 1 thus diverging, when the rod 13 moves towards the casings 4, whilst fig. 3c shows the rotation of the hydrofoil blades 1 thus converging, when the rod 13 moves in the opposite direction. This reciprocating motion assures the oscillation of the hydrofoil blades 1 and therefore the propulsion of the vessel. Figs. 3d and 3e, instead, show two similar configurations, each of them corresponding to two different steering angles, 90 and 180 degrees respectively. The hydrofoil blades 1 reach said steering angles by rotating the shaft 11 that, through the steering box 8 and the telescopic shafts 9, rotates the endless screws 12, each, as previously shown, gears a crown wheel 4b on casing 4.
Fig. 4 shows a further embodiment according to the present invention in which a single outer casing 4c, housing a pair of inner casings 4 and hydrofoil blades 1, is used. Such embodiment employs a parallel motion linkage. Each hydrofoil blade 1 is mounted onto an arm 5, which is connected to a rod 13 by at least four parallel motion connecting rods 7. Said connecting rods 7 are, indeed, hinged at their opposite ends between the rod 13 and the arm 5. On said arm 5 is also arranged the flap mechanism 3 which even acts as a damper. The reciprocating motion of the rod 13 provides for the vessel propulsion, whilst the previously described endless screw mechanism provides for steering operation by the rotation of the shaft 11.
In yet another embodiment, illustrated in figs. 5 and 5a, the hydrofoil blades 1 may be movably attached directly to the outer surface of a vessel by hinges 20, without the use of any casing, the reciprocating motion is transmitted from rod 13 to the said hydrofoil blades 1 by connecting rods 7, and providing the steering operation by the actuation of the steering mechanism 11 acting on the same rod 13 as shown in fig. 5a. Such embodiment, if preferred, can be a much lighter, simpler, and less expensive variant which can be used also on pedal powered pleasure craft.
Finally in figs. 6 and 7 multiple hydrofoil blades 1 are arranged on the same casing 4, using one of the previously described systems both for propulsion motion and steering operation.
Fig. 8 illustrates, in a perspective view, a strut mounted embodiment according to the present invention. Such embodiment differs from previously described embodiments by the fact that the casings 4 are formed on a strut 18 and back-to-back arranged and are hinged directly to the connecting rods 7. Said strut is rotatable in order to assure the steering operation of the vessel on which it is mounted. The embodiment in fig. 8 offers the further advantage of keeping vortices, generated during the propulsion motion of the hydrofoil blades 1, away from the surface of said vessel. It can be adapted to any displacement or planing hull, or to an outboard motor. The embodiment in fig. 8 can be used to propel and steer hydrofoil boats, lifting the hull clear of the water surface, and giving the said boats unlimited maneuverability. A given vessel can also be equipped by one or more such struts 18 each of which incorporating one or more oscillating hydrofoil systems according to the present invention. The height of the vessel's hull from the water can be controlled and adjusted, as desired, by changing the angle of attack of the hydrofoil blades 1, depending on the weight of the same vessel and the desired speed. In order to assure the aforementioned features and advantages of the embodiment on fig. 8, a separate mechanisms are provided for propulsion motion and steering operation. With reference to figs. 8a and 8b, the strut 18 is provided with a pair of housings 21 for the casings 4 each, in turn, provided with a hole 4' and a hinge 4". The hole 4' houses the hydrofoil blade axle 1' which is also connected to the flap mechanism 3, whilst the hinge 4" is connected to a first end of a rod 7, the other end of which is hinged with an end of a yoke 6. Said yoke 6 is also hinged to a rod 13 which has a reciprocating motion thus delivering the necessary oscillation to the hydrofoil blades 1. A pitch controller 17, or any similar mechanism, which is fixed to said rod 13 and can be remotely actuated, is hinged to one end of the yoke 6 in order to adjust the attack angle of the blades 1. Figs. 8c to 8e illustrate different displacements reachable by the hydrofoil blades 1 driven by the just described propulsion mechanism and pitch controller. Finally, the steering operation is assured by an actuator 8 which controls a crown wheel, or any similar mechanism, on the strut upper perimeter, provided with a gearing profile.
In all the above described embodiments according to the present invention the hydrofoil blades 1 can be rigid or flexible, or any combination of both, as preferred, for optimum efficiency at any moment and in any condition as need be. The flap mechanism 3, can be preset, or remotely actively controllable or variable, as preferred. Said flap mechanism 3 can also be lockable or not lockable as preferred.

Claims

A system for propulsion and steering of waterborne craft, comprising:
(i) at least two of hydrofoil blades (1), with at least one hydrofoil blade (I) rotatably connected to each of at least two casings (4),

(ii) at least one flap mechanism (3) hinged on each hydrofoil blade (1), which can be either a preset or a remotely actuated damping mechanism, and

(iii) at least two casings (4), each rotatably connected to at least one hydrofoil blade (1) each, and to the tlap mechanism (3), and to each other,

(iv) at least two arms (5) hinged to and gearing said casings (4), through at least two endless screws (12), or gearing each other as in figs.2, and 2a, and

(v) at least two connecting rods (7) hinged to said arms (5), and

(vi) at least one transmission rod (13) hinged to said connecting rods (7)

(vii) at least one gearbox (8), connected to said at least two casings (4) by at least two telescopic shafts (9), and each gearing the casings (4) by at least two endless screws (12),

(viii) at least two endless screws (12) on said two arms (5), gearing said casings (4),
characterized by the fact that said at least two casings (4) on said waterborne craft can be rotated by an angle between 0 and 360 degrees around their own axis synchronously in the same direction to steer die same waterborne craft by the rotation of the shaft (11), which is transmitted through said gearbox (8), to each telescopic shaft (9) that, in turn, rotates each endless screw (12), thus rotating the corresponding casing (4) synchronously in the same direction, and partially rotated, by transmitting power through the reciprocation of the transmission rod (13) to the connecting rods (7), to the arms (5) through the endless screws (12), to the casings (4), and thus to the hydrofoil blades (1) so as to rotate antisymmetrically said casings (4) and oscillate said hydrofoil blades (1) in unison antisymmetrically for a selected angle with respect to the direction of their neutral position, to propel the craft.
The system for propulsion and steering of waterborne craft according to claim 1, in which said casings (4) are arranged on a rotatable strut of said waferborne craft, are connected by slideable rods (7), hinged at both ends to a driven yoke (6), slideable and rotatable on the lying plane of said casings (4).
The system for propulsion and steering of waterborne craft according to claim 2, in which said yoke (6) can be remotely actuated in order to adjust the angle of attack of the hydrofoil blades (1), and power-driven in order to propel the same waterborne craft.
A system for propulsion and steering of waterborne craft, according to claim 1, excluding the casings, comprising at least a pair of hydrofoil blades (1) each rotatably fixed directly to a submerged or submersible part of said waterborne craft and hinged to connecting rods which, in turn, are hinged to at least one slideable transmission rod (13) which can reciprocate longitudinally to make the hydrofoil blades (1) oscillate in unison antisymmetrically for a selected angle with respect to the direction of their neutral position, to propel the craft, and which can also slide sideways on the lying plane of said hydrofoil blades (1) when actuated by steering mechanism (11) to achieve steering.
A system for propulsion and steering of waterborne craft, according to claim 1 , comprising at least a pair of hydrofoil blades (1) in which both the propulsion transmission and the steering mechanism, are combined into at least one housing (15) on each casing (4), each governed by at least one main drive unit (16), so that said casings (4) rotate antisymmetrically and oscillate said hydrofoil blades (1) in unison antisymmetrically for a selected angle with respect to the direction of their neutral position, to propel the craft, and said at least two casings (4) can be rotated by an angle between 0 and 360 degrees around their own axis synchronously in the same direction to steer the same waterborne craft,
The system for propulsion and steering of waterborne craft according to claim 1, in which the connecting rods (7), and the arms (5) are set up in parallel motion on a single casing (4) with a separate steering mechanism.