DEVICE FOR CONVERTING A BIDIRECTIONAL ROTATION MOTION AROUND TWO ROTATION AXES INTO AN UNIDIRECTIONAL ROTATION MOTION AROUND A SINGLE ROTATION AXIS, AND POWER PRODUCTION SYSTEM USING SAID DEVICE

The present invention relates to the field of motion transmission, and to the field of energy production. In particular, the present invention relates to a device for converting a bidirectional rotation motion around two shafts or on two rotation axes into a unidirectional rotation motion around a single axis, and to a power production system using said device.

US 6 247 308, in the name of Yedidia Sollel Tel Aviv, discloses a transmission device for converting a rotation motion around a first shaft into a rotation motion around a second shaft, perpendicular to the first shaft.

The present invention provides a device for converting a bidirectional rotation motion around two shafts into a unidirectional rotation motion around a single axis.

Compared to the prior art, the present invention allows, from two input rotation motions on two perpendicular shafts, to have a rotation motion on an output rotation axis, in a single direction of rotation, the direction of rotation of the output rotation axis being set by the construction of the device.

Whatever the direction of the input rotation motion, the direction of rotation of the output rotation axis is set and is always the same.

This device can thereafter be used in a power production system.

Indeed, means introducing an instability can be provided on at least one of the two input shafts, that

drive at least one of the input shafts into rotation, whether in a clockwise or anticlockwise direction.

If the means introducing instability, together with the device, are appropriately disposed into a suitable environment acting on said means, a continuous rotation of the output axis, in a single direction of rotation, can be obtained.

The instability introducing means can take the form, for instance, of a shape having several faces, each face being in a different plane. The shape is thereafter attached to at least one of the two input shafts of the rotation motion converting device, and as stated earlier, the assembly is arranged into an environment, e.g. a fluid flow, acting on at least one of said faces of the shape. The action of the environment on at least one of said faces of the shape will result in the three-dimensional motion of the shape, and as a consequence a rotation motion, whether clockwise or anticlockwise, of at least one of the input shafts of the rotation motion converting device, which in turn will result in a rotation motion, in a single direction of rotation, on the output rotation axis.

A power production device, such as an alternator, can be arranged on the output shaft, in order to be able to produce power with the motion of the output shaft.

An application of such a device can be, for example, a power production device using water streams. As the instability introducing means move with the stream of water, such a system is friendly for the environment, as it will cause no harm to aquatic wildlife, contrary to current power production devices, such as turbines, whose blades can damage the wildlife. The system can be used in the sea, whether offshore or close to the coast, and in rivers.

The rotation motion converting device of the invention can have different sizes (from centimetres to several meters), according to the application. When used in the sea, the size (several meters) of the power production system, rotation motion converting device and instability introducing means, is such that it can collect an important quantity of energy from the streams.

The only part of the system that needs to be into contact with water is the instability introducing means, therefore the rotation motion converting device and its various mechanisms do not need to be immersed, thereby diminishing the corrosion of mechanical parts with respect to, for example, a turbine, a good part of which needs to be immerged to operate properly. The ease of maintenance of the different parts of the system is also improved. The whole system could also be arranged in a sealed unit, totally immersed, according to the application.

The power production system can also have a slightly inferior size (~m) , to be adapted to fit in a any kind of vessel, such as sailboats. The system can be used to produce power for the sailboat to load batteries, for example, the system being immersed and electrically connected to the boat. The immersed part of the system can collect energy from the water streams or from the tide, or from any kind of wave, and, with an alternator on the output axis, produces power from the movement on the input shafts. This can be useful, especially as vessels are equipped nowadays with many electronic devices that need to be powered. The power production system of the invention allows to have less batteries on-board, leaving more space for other loads, and also allows more time spent without the need to go in a port to load the batteries.

The power production system can also be used with air streams, to produce power in remote environments, where water streams cannot be used and where power is necessary.

The power production system of the invention can also have a small size (cm) to be able to be carried upon by a human or an animal, whose motion creates sufficient instability on the input shafts to result in a rotation of the output shaft. Small quantities of energy can thereby be produced to power low-power electronic or electrical devices, such as GPS markers, to track wild animals, or cell phones, whose batteries could be powered by such a system.

Another implementation of the device could be to use it under a surface on which people are walking. The vibration caused on the surface by people steps can be the source of instability, thereafter used as input to one or several power production system in series according to the invention, to produce power from the vibrations produced by people walking on the surface. This can be used in places where a lot of people are walking, such as in stations, airports, etc.

The amount of produced power can be varied, by mechanical transmission means, between the input shafts and the output rotation axis, according to the gear ratios between the input shafts and the output rotation axis.

The device according to the invention can be used in various situations, where instability can be used as input to produce power.

For example, the device could be used in kitchen or other areas in homes, where the rotation motion at the end of the shaft is used.

The device according to the invention can also be used, for example in factories, where a user has to produce

a rotation motion. The invention could then be used, avoiding the risk of RSI (repetitive strain injury) for the user .

The device of the invention could also be used in toys, such as skateboards or the like, where the user, by a three-dimensional motion on the board, produces a rotation motion .

The disabled could also easily use the device, instability at one end of the device producing a rotation motion of the output shaft. Many applications could be found for this particular use, such as acting on a mechanical device to help the disabled in their everyday life.

The dimensions, the gear ratios as well as the transmission means between the input shafts and the output shaft can be adapted for a particular use of the device to create a power source.

In the application, unless stated otherwise, bidirectional, when applied to a rotation motion around a rotation axis, designates a rotation motion around the shaft that can be both clockwise and anti-clockwise.

Similarly, unless stated otherwise, unidirectional, when applied to a rotation motion around a rotation axis, designates a rotation motion around the shaft that can be either clockwise or anticlockwise.

An object of the invention is therefore a device producing unidirectional rotation motion as output from any bidirectional rotation motion as input, comprising:

- a first input rotation axis;

- a second input rotation axis, orthogonal to the first input rotation axis;

- an output rotation axis;

transmission means provided between the first input rotation axis and the output rotation axis and between the second input rotation axis and the output rotation axis, in order to convert a clockwise or anti-clockwise rotation motion on the first input rotation axis and/or on the second input rotation axis into a unidirectional rotation motion on the output rotation axis, characterized in that one of the first input rotation axes is the same as the output rotation axis.

Preferably, the transmission means between the first input rotation axis and the output rotation axis and the transmission means between the second input rotation axis and the output rotation axis each comprise at least a pair of unidirectional members, wherein for each pair, one member is activated by a first rotation direction on the corresponding input rotation axis, the other member of the pair being activated by a second rotation direction on the corresponding input rotation axis, opposite to the first rotation direction.

The unidirectional members can be one-way clutches, unidirectional hydraulic turbines, hydraulic pumps, hydraulic drives, etc.

Preferably, the transmission means from the first input rotation axis to the output rotation axis and the transmission means from the second input rotation axis to the output rotation axis are independent.

The transmission from the first input rotation axis is therefore directly transmitted on the output rotation axis, and the transmission from the second input rotation axis is directly transmitted on the output rotation axis

Preferably, the transmissions means between the input rotation axes and the output rotation axis are any of

toothed gears, chains and cogs, belts and pulley wheels, hydraulic drives and any combination thereof.

For example, the transmission of rotation between the input axes and the output axis can be through mechanical transmission means, or through fluids.

Preferably, the shafts are mounted in alignment with the two input rotation axes to provide the bidirectional input rotation motion on the two input rotation axes.

Preferably, a shaft is mounted in alignment with the output rotation axes, the unidirectional rotation output motion being transferred to the shaft by the transmission means.

Preferably, the gear ratios between the first input rotation axis and the output shaft, and between the second input rotation axis and the output shaft are identical .

Preferably, the gear ratios between the first input rotation axis and the output shaft, and between the second input rotation axis and the output shaft are different .

Preferably, the transmission means for the input rotation axes are hydraulic drives, any bidirectional rotation movement on the input rotation axis producing an output fluid flow, the output unidirectional rotation motion of the device being produced by an unidirectional hydraulic turbine driven by the fluid flow.

Another object of the invention is a power production system, characterized in that it comprises:

- the device as defined above;

- input means cooperating with an outer environment of the system, to create any bidirectional rotation motion on any of the input rotation axes;

- power production means provided on the output rotation axis to create power from the unidirectional rotation motion created on the output rotation axis.

Preferably, said power production means is an alternator .

Preferably, the outer environment is a fluid flow .

Preferably, that the outer environment is the sea and in that input means consist in a spherical buoy, into which are formed two parallel beams, both beams forming in use a chord of the sphere in the same substantially horizontal plane, the device being pivotally mounted between these two parallel beams, the pivoting axis of the device with respect to said beams constituting the first input rotation axis of the device, a weight being pivotally suspended to the device, the pivoting axis of the suspended weight being perpendicular to the first input rotation axis and constituting the second input rotation axis of the device, a second weight being centrally fixed to the base of the buoy, and the buoy having an offset anchorage producing a non stable movement of the buoy and therefore a rotation of the device on its two input rotation axes to provide bidirectional rotation movements on the input rotation axes of the device.

Preferably, the two parallel beams are formed in the central horizontal plane of the sphere.

The present invention will now be described further, with reference to the accompanying drawings, on which:

- Figure 1 is a perspective view of a rotation motion converting device according to a first embodiment of the invention, for converting a bidirectional rotation

motion around two input shafts into a unidirectional rotation motion around one output shaft;

- Figure 2 is an view in elevation of the device of Figure 1;

Figure 3 is a side view of the device of Figure 1 ;

Figure 4 is a perspective view of the device according to the invention in another embodiment of the invention;

Figure 5 is a view through section AA of Figure 4;

Figure 6 is a view through section BB of Figure 4;

Figure 7 is an view in elevation of the detail D of Figure 5;

- Figures 8A to 8C are views through sections EE, FF and GG of Figure 7, respectively;

Figure 9 is a view through section CC of Figure 4;

Figure 10 is a view similar to the view of Figure 9, with a third rotation motion conversion embodiment between the input shafts and the output shaft;

Figure 11 is a cut-away side view of the device according to the invention in another embodiment of the invention;

Figure 12 is a cut-away view in elevation of the device in the embodiment of Figure 11;

- Figures 13A, 13B, 13C are top, front and side views of a power production system according to an embodiment of the invention;

- Figure 14 is an top view of a fifth embodiment of a device according to the invention; and

Figure 15 shows an hydraulic pump used in the device of Figure 14.

Referring now to Figures 1-3, a first embodiment of the device for converting a bidirectional rotation motion around two perpendicular input rotation axes into a unidirectional rotation motion around a single output rotation axis is depicted, the gear ratio between the input rotation axes and the output rotation axis being of 1:1 in this embodiment.

In this embodiment, an output shaft 1 is rotatably mounted on the output rotation axis, also referenced with the reference numeral 1.

A rotatable housing 5, more fully described thereafter, is rotatably mounted on said shaft 1, in a manner more fully described thereafter, the rotation axis of said rotatable housing 5 being the same as the output rotation axis 1, and constituting the first input rotation axis, also referenced 1.

A shaft 2, more fully described thereafter, is rotatably mounted at one end IB of the output shaft 1, perpendicularly to the output shaft 1, and constitute the second input rotation axis, perpendicular to the first input rotation axis and to the output rotation axis.

The shaft 1 is supported at one end IA by two bearings 2A, 2B mounted at the respective centres of two parallel, spaced-apart, vertical walls 3A, 3B disposed on an horizontal support member 4.

A housing 5, on the other end IB of the shaft 1, is formed with two hollow cylindrical parts 5A, 5B, whose longitudinal directions are orthogonal, and of different lengths, the cylindrical part 5A being in the direction of the output rotation axis 1.

The cylindrical part 5A is connected at one of its ends to the centre of the cylindrical part 5B, thereby forming a T-shaped housing 5. The other end of the cylindrical part 5A supports a bearing 2D to support the shaft 1, whose end IB is inside the cylindrical part 5A.

The housing 5 can be driven into rotation around shaft 1, clockwise or anticlockwise when viewed from the left-hand side of Figure 2.

In the following description, unless stated otherwise, the directions of rotation will be considered as viewed from the left-hand side of Figure 2.

A gearing mechanism, mounted intermediate the ends IA, IB of shaft 1 comprises three bevel gears 6A, 6B, 6C, two bevel gears 6A, 6B being mounted on shaft 1, and meshing through a third bevel gear 6C, supported by a third bearing 2C mounted at the centre of a third vertical wall 3C, mounted on the horizontal support member 4, orthogonal to the first two walls 3A and 3B.

A first one-way clutch 7A supported by the bearing 2D, locking on shaft 1 when the cylindrical part 5A of the housing 5 is rotated clockwise, is disposed between the housing 5 and the first bevel gear 6A.

A second one-way clutch 7B is mounted with the bevel gear 6B, the one-way clutch locking on shaft 1 when the bevel gear 6B rotates clockwise.

Thus, a clockwise motion of the cylindrical part 5A of housing 5 will result in the one-way clutch 7A locking on shaft 1 at its end IA. The clockwise rotation motion of the bevel gear 6A results in the bevel gear 6C rotating clockwise, with reference to Figure 2, which in turn results in the bevel gear 6B rotating anti-clockwise, thereby not locking the one-way clutch 7B on shaft 1. The clockwise rotation motion of the cylindrical part 5A of housing 5 therefore results in output shaft 1 rotating clockwise through the one-way clutch 7A.

Similarly, when the cylindrical part 5A of housing 5 is rotated anti-clockwise, the one-way clutch 7A does not lock on shaft 1, and the rotation motion of the cylindrical part 5A of the housing 5 is transmitted via bevel gears 6A, 6C to the bevel gear 6B . The anti-clockwise rotation motion of the bevel gear 6A results in the bevel gear 6C rotating anti-clockwise, with reference to Figure 2, which in turn results in the bevel gear 6B rotating clockwise, thereby locking the one-way clutch 7B on shaft 1. The anti-clockwise rotation motion of the cylindrical part 5A of housing 5 therefore results in shaft 1 rotating clockwise through the one-way clutch 7B.

The gearing mechanism formed by the bevel gears 6A, 6B, 6C and the one-way clutches 7A and 7B thereby ensures that any rotation, whether clockwise or anticlockwise of the first cylindrical part 5A results in the output shaft 1 rotating clockwise.

The second input shaft 2 has two halves 2A, 2B, respectively.

These two halves are supported by two bearings 8A, 8B, at each end of the second cylindrical part 5B of housing 5.

Each half 2A, 2B is partially introduced in the cylindrical part 5B of housing 5, the ends 2Al, 2Bl of the two-halves 2A, 2B of shaft 2 introduced in the cylindrical part 5B of the housing 5 bearing a bevel gear 9A, 9B, respectively, the two other ends 2A2, 2B2 of the two halves 2A, 2B of input shaft 2 projecting from each side of the cylindrical part 5B of housing 5.

The bevel gears 9A, 9B of the two halves 2A, 2B mesh with a third bevel gear 9C at the end IB of shaft 1, where the two cylindrical parts 5A, 5B of housing 5 are connected.

An part 10 is formed with two parallel walls HA, HB connected to an third wall 12, perpendicular to the two walls HA, HB. Each wall HA, HB, has at its centre a one-way clutch, 13A, 13B, respectively.

The ends 2A2, 2B2 of the two halves 2A, 2B respectively engage with one-way clutches 13A, 13B supported by the walls HA, HB.

When viewed from the front of Figure 3, the oneway clutch 13A locks when rotated anti-clockwise, and the one-way clutch 13B locks when rotated clockwise.

If we refer in particular to Figure 3, a rotation from top to bottom of the part 10 results in the one-way clutch 13A locking of the half 2A of shaft 2, to rotate the half 2A anti-clockwise, when viewed from the front of Figure 3, the one-way clutch 13B remaining unlocked.

The anti-clockwise rotation of half 2A of shaft 2 results in bevel gear 9A rotating anti-clockwise, when viewed from the front of Figure 3 and therefore results in the bevel gear 9C rotating clockwise.

Similarly, a rotation from bottom to top of the part 10 results in the one-way clutch 13B locking of the half 2B of shaft 2, to rotate the half 2B anti-clockwise, when viewed from the front of Figure 3, the one-way clutch 13A remaining unlocked.

The anti-clockwise rotation of half 2B of shaft 2 results in bevel gear 9B rotating anti-clockwise, when viewed from the front of Figure 3 and therefore results in the bevel gear 9C rotating clockwise.

Therefore, any rotation around shaft 2, whether clockwise or anti-clockwise, results in the clockwise rotation of shaft 1.

Any rotation of the housing 5 around rotation axis 1 also results in a clockwise rotation of shaft 1.

In the latter embodiment described with reference to Figure 1-3, the gear ratio between the input shafts and the output shaft is 1:1.

A torque appears at the end IB of shaft 1 with this gear ratio of 1:1. This torque, which increases with the gear ratio, can be reduced using other transmission means between the input shafts and the output shaft, as explained with reference to the second embodiment of the invention .

The Figures 4-9 describe another embodiment of the present invention, where the transmission between the input gears and the output gears is by means of pulleys and belts, which suppresses the torque at the shaft end IB.

As can be seen from Figure 4, the device according to the second embodiment of the invention is formed with a mobile housing 50, supported by a bearing 51 in a hollow disc 52, said disc being mounted on a vertical wall 30 of an horizontal support member 40, as shown in Figure 4.

The mobile housing 50 is formed with two cylindrical orthogonal parts, 5OA and 5OB respectively, whose longitudinal directions respectively match the directions of the two input rotation axis 1 and 2. The longitudinal direction of the cylindrical part 5OA corresponds to the direction of the output shaft S, and the longitudinal direction of the cylindrical part 5OB corresponds to the direction orthogonal to the output shaft S, the direction of the output shaft S constituting the output rotation axis.

The housing 50 is rotatable clockwise or anticlockwise around output shaft S.

Each end of the cylindrical part 5OB is a vertical wall, IIOA and HOB respectively, the vertical wall HOA only in this embodiment being provided at its centre with a bearing, respectively 130A.

These bearings 130A, similarly to the bearings of Figure 2, support two halves (only half 2A shown on Figures) of an input shaft 2, whose ends inside the housing 50 bear an element similar to the part 10 of Figure 2 and 3, not shown in this embodiment. As for the prior Figures 2 and 3, the part is rotatable clockwise or anti-clockwise around two halves 2A of the input shaft 2, when viewed from the left-hand side of Figure 4.

In the following, and unless states otherwise, the directions of rotation will be those viewed from the left-hand side of Figure 4.

If we refer more particularly to Figure 5A, we can see in more detail the transmission from the input shaft 2 to the output shaft S, explained with reference to wall HOA of the cylindrical part 50B of housing 50 in Figure 4.

As can be seen from Figure 5, the input half shaft 2A is hollow. An intermediary shaft I is supported by bearings inside the half input shaft 2A.

The half input shaft 2A bears at its distal end 2Al a flat rectangular bar 9OA, whose surfaces are parallel to the wall 11 OA.

As can be seen from Figure 7, the distal end of this rectangular bar is formed with two holes, respectively Tl and T2, both being through holes in the flat rectangular bar 9OA in the direction of the half input shaft 2A, the two holes Tl, T2 being radially spaced at the distal end of the vertical bar 9OA.

The first hole Tl bears a first axis 91, which protrudes from the two sides of the bar 9OA, and the second hole bears a second axis 92, protruding only from the surface of the flat rectangular bar 9OA facing the inside of the cylindrical part 5OB, and not protruding from the surface of the flat rectangular bar 9OA facing the inner surface of the wall HOA.

The end of the axis 91 protruding from the rectangular bar 9OA towards the inner face of the wall IIOA bears a wheel 93, rotatable with the axis 91, that runs on an inner annular ring 94, whose thickness on the inner cylindrical wall of the cylindrical part 50B corresponds to the thickness of the wheel 93, the annular ring 94 being disposed on the inner side of the wall HOA.

The other end of the axis 91, towards the inside of the cylindrical part 50B bears in this order, from the surface of the flat rectangular bar 9OA: a gear 95 and a pulley 96, both being rotatable around the axis 91, the pulley 96 incorporating a one-way clutch.

The axis 92 bears in this order, from the surface of the flat rectangular bar 9OA a gear 95' , meshing with

the gear 95 on the axis 91, and a pulley 96', the gear 95' and the pulley 96' both being rotatable around the axis, and the pulley 96' incorporating a one-way clutch, the oneway clutches of the pulleys 96 and 96' locking in the same direction of rotation, clockwise when viewed from the front of Figure 8C.

The intermediate axis I also bears a pulley 97, located immediately below the pulleys 96 and 96' in the vertical direction.

A belt 98 connects the pulleys 96, 96' and 97, as shown in Figure 9, where the belt 98 is driven by the pulleys 96 and 96' incorporating one-way clutches of the flat rectangular bar 9OA, in order to rotate the intermediate axis I using the pulley 97.

When the input half axis 2A rotates clockwise, the flat rectangular bar 9OA is rotated clockwise around the half axis 2A, resulting in the wheel 93 running on the inner annular ring 94, the wheel rotating anti-clockwise, as viewed from Figure 8A. As a consequence, the axis 91 will be rotated anti-clockwise by the wheel 93, as will be the gear 95. The one-way clutch of the pulley 96 does not lock, therefore the pulley 96 is freewheeling.

The anti-clockwise rotation of the gear 95 results in a clockwise rotation of the gear 95' on the axis 92. As a consequence, the axis 92 rotating clockwise, so will the pulley 96' , as a consequence of the locking of the one-way clutch incorporated in said pulley 96' .

The belt 98 is therefore driven by the pulley 96', and the belt itself rotates clockwise the pulley 97.

The clockwise rotation of the pulley thereafter results in the intermediate axis I rotating clockwise

Similarly, when the half input shaft 2A rotates anti-clockwise, as viewed from Figure 9, the flat

rectangular bar 9OA is rotated anti-clockwise around the half input shaft, resulting in the wheel 93 running on the inner annular ring 94, the wheel 93 rotating clockwise, as viewed from Figure 8A. As a consequence, the axis 91 will be rotated clockwise by the clockwise rotation of the wheel 93, so will be the first gear 95 of the axis 91. The pulley 96 of the axis 91 will be rotated clockwise, its incorporated one-way clutch locking in this direction of rotation .

The clockwise rotation of the first gear 95 of the axis 91 results in the anti-clockwise rotation of the second gear 95' of the axis 92. The axis 92 rotating anti- clock-wise, the incorporated one-way clutch of the pulley 96' will not lock, and the pulley 96' will freewheel.

The pulley 96, rotating clockwise when viewed from Figure 8C, drives the belt 98, so that it turns clockwise, as viewed from Figure 9. As previously seen, the belt 98 rotates the pulley 97 on the intermediate axis I, thereby rotating the intermediate axis clockwise.

A clockwise rotation or an anti-clockwise rotation of the half axis 2A of the shaft 2 therefore results in a clockwise rotation of the intermediate shaft I.

The rotation of the intermediate axis I is thereafter transmitted to the output shaft S by gear means similar to the gear means 9A, 9B depicted in Figure 3, and not shown in this embodiment.

Figure 6 illustrates the way a rotation motion of the cylindrical part 5OA of housing 50 of Figure 4 is transmitted to the output shaft S.

A bearing 51 mounted on the hollow disc 52 of the wall 30 supports the cylindrical part 5OA.

The end wall of the cylindrical part 5OA of the housing 50 which contacts the hollow disc 52 has at its centre an opening 53, which is connected to a hollow cylinder 54. The output shaft S passes through the opening 53 and the cylinder 54, towards the inside of the hollow disc 52, as shown in Figure 6.

Still referring to Figure 6, the cylinder 54 has at its end located inside the hollow disc 52, a flat rectangular bar 9OB, whose construction is similar to the construction of flat rectangular bar 9OA of Figures 5, 8, 8A-8C and 9.

An assembly similar to the one detailed with reference to Figures 5, 8, 8A-8C and 9 is used to drive into rotation the output shaft S, unidirectionally, by means of a pulley 99 disposed on the output shaft S, similarly to the pulley 97 on the intermediate shaft I, connected to the gears and pulleys incorporating one-way clutches on the flat rectangular bar 9OB, by means of a belt, as detailed above with reference to Figures 5, 8, 8A- 8C and 9.

Figure 10 shows a third embodiment, very similar to the embodiment detailed above, where the belt and pulleys are replaced by gears. Toothed gears 196, 196' and 197 replace the pulleys 96, 96' and 97, whereas a toothed gear 198 replaces the belt 98. The construction of the housing is otherwise similar.

The Figures 11 and 12 show a fourth embodiment.

The outer structure of the housing is the same as in Figure 4, the inner mechanical transmission changing.

Only the transmission from the input shaft in the cylindrical part 5OB, transverse to the output shaft is shown for more clarity, the transmission from the input

shaft parallel with the output shaft being the same as previously described, with reference to Figure 6.

In this fourth embodiment, an input shaft 2 is supported by two bearings 230A and 230B, at each end of the cylindrical part 5OB. Inside the cylindrical part 5OB of the housing 50, the shaft 2 supports a large gear 294. The radius of the gear 294 is slightly inferior to the radius of the inner part of the cylindrical part 5OB.

The gear 294 is rotated clockwise and anticlockwise with the input shaft 2.

Two plates 290A and 290B, parallel to each other, are provided inside the cylindrical part 50A of the housing 50, extending vertically from the bottom of the housing to the top of the housing, the plates 290A and 290B, as shown in Figure 12 being shifted from the central part of the cylindrical part 50A of the housing 50. The surfaces of the plates 290A and 290B are parallel to the direction of the output shaft S .

Two axis 291 and 292 extend between the two plates 290A and 290B, the two axis being supported on each plate into through holes, respectively T21, T22 and T23, T24 formed on the plates 290A and 290B, respectively at a distance above the output shaft S.

The first axis bears on the side of the plate 290A opposite to the output shaft S a small gear 293, meshing with the large gear 294, and rotating with the first axis 291 clockwise or anticlockwise. Between the two plates 290A and 290B, the first axis 291 bears, similarly to the system described in relation to Figure 7, in this order, an interlocking gear 295 and a first worm gear 296.

The second axis 292 does not protrude outside the space between the two plates 290A and 290B, and supports in this order a second interlocking gear 295', meshing with

the first interlocking gear 295, and a second worm gear 296' .

The worm gears 296 and 296' each include a oneway clutch, both one-way clutches locking in the same direction of rotation, and both engage with the output axis S to drive it into rotation when they are activated (one way clutch incorporated locks) .

Similarly to the system described in relation to Figure 7, when the input shaft rotates clockwise, as seen from Figure 11, so does the large gear 294.

The large gear drives into rotation the small gear 293 anticlockwise. Supposing the one-way clutch incorporated in the first worm gear 296 locks when the axis 291 rotates clockwise, the anticlockwise rotation of the small gear does not lock the worm gear 296.

The anticlockwise rotation of the axis 291 implies, through the interlocking gears 295 and 295', a clockwise rotation of the second axis 292.

The clockwise rotation of the second axis 292 in turn locks the one-way clutch incorporated in the second worm gear 296', resulting in the clockwise rotation of the output shaft S .

Similarly, when the input shaft 2 rotates anticlockwise, the worm gear 296 will lock (the worm gear 296' remaining unlocked), resulting in the clockwise rotation of the output shaft S.

The second and third embodiments allow a higher ratio between the input shafts and the output shaft, without a torque on the output shaft.

The fourth embodiment shows that the transmission of the rotation can also be off-centred, contrary to the first to third embodiments.

Figures 14 and 15 show an hydraulic embodiment of the invention, particularly adapted to large size devices, where the torques on mechanical transmission means is too important .

In this fifth embodiment, two independent hydraulic pumps are used to transmit the input rotation motion of each input axis to the output rotation axis.

The device 400 according to the fifth embodiment comprises a generally rectangular housing 401. A bearing 402A, 402B, 402C and 402D is mounted at the centre of each wall of the housing 401.

Each bearing 402A, 402B, 402C and 402D support a shaft, respectively 403A, 403B, 403C and 403D, so that one end of each shaft 403A, 403B, 403C and 403D protrudes inside the housing 401, the other end of each shaft 403A, 403B, 403C and 403D protruding outside the bearing. The shafts 403A, 403B, 403C and 403D are aligned in pairs, so that shafts 403A, 403B are aligned, and their rotation axis constitute the second input rotation axis, and shafts 403C, 403D are aligned, and their rotation axis constitute the first input rotation axis.

A shaft from each pair, respectively 403B, 403D, has its end inside the housing 401 sealingly connected to an hydraulic pump, respectively 404B, 404D.

The hydraulic pumps 404B, 404D are more fully described with respect to Figure 15.

Each hydraulic pump 404B, 404D (pump 404B depicted on Figure 15) generally has a half-sphere shape, whose inside is sealingly separated by a pivoting paddle 405 into two chambers 406A, 406B of equal dimensions in the steady state position. The input shaft 403B is sealingly connected to the paddle 405, and drives into rotation the

paddle 405 when a rotation motion is exerted on the end of the shaft 403B protruding outside the housing 401.

Each chamber 406A, 406B is provided at its lower end with a pair of one-way valves, respectively 407 and 408 for chamber 406A, and 409 and 410 for chamber 406B, the one-way valves 407 and 408, and 409 and 410 in a chamber operating in opposite directions, the one-way valves 407 and 410 being inlet one-way valves, the one-way valves 408 and 409 being outlet one-way valves.

The inlet one-way valves 407 and 410 are both connected to the same inlet pipe 411, and the outlet oneway valves are both connected to the same outlet pipe 412.

Each pair 407, 408 and 409, 410 therefore comprise a inlet valve 407, 410, opening when the pressure in the inlet pipe 411 is greater than the pressure in the related chamber, and an outlet valve 408, 409 opening when the pressure in the related chamber is greater than the pressure in the outlet pipe 412.

As stated above, the lower end of the paddle 405 is linked to the related input rotation axis 403B, and the movement of the related input rotation axis 403B moves the paddle 405 and creates pressure differentials in the chambers 406A, 406B, that open the corresponding one-way valves 407, 408, 409, 410.

The outlet pipe 412 is connected to an output pipe 413, whose direction is the same as the input rotation axis 403D, and whose distal end features a unidirectional hydraulic turbine (not shown on the drawings) , that creates the unidirectional rotation motion on the output rotation axis, the output pipe being aligned with the input rotation axis 403D. The output pipe 413 is then looped back on the inlet pipe 411, so that the hydraulic circuit (411, 412, 413) is closed.

Any bidirectional rotation movement on the input shafts 403B, 403D therefore creates a unidirectional movement on the output rotation axis.

Figures 13A, 13B, 13C show a power production system 500, according to an embodiment of the invention, to be used to produce power in the sea. It consists in a spherical buoy 501, into which are formed two parallel beams 502, 503, both beams 502, 503 forming in use a chord of the sphere 501 in the same substantially horizontal plane, a device 504 according to the invention being pivotally mounted between these two parallel beams 502,

503, the pivoting axis of the device 504 with respect to said beams 503, 504 constituting the first input rotation axis of the device 504.

A weight in the form of a pendulum 505 fixed to a U-shaped part 508, is pivotally suspended to the device

504, the pivoting axis of the pendulum 505 being perpendicular to the first input rotation axis and in the same plane, and constituting the second input rotation axis of the device 504.

A second weight 506 is centrally and symmetrically fixed to the base of the buoy 501, inside the buoy 501, so that the second weight 506 is uniformly provided on the base of the buoy 501 in the steady state position of the pendulum 505.

The buoy 501 has an anchorage 507, offset from the steady state position of the pendulum 505, thereby producing a non stable movement of the system 500 when the tide moves the system 500, as the pendulum 505 and the offset anchorage 507 both impart to the system a different steady state position. This non-stable movement produces a movement of the device 504 with respect to the first and second input rotation axes, and therefore provides

bidirectional rotation movements on the input rotation axes of the device 504, to create power with the device, as stated above.

Other constructions working on this very same principle of the invention can be readily found, as various means exist to effect the transmission between the rotation axes shafts and the output rotation axis.

Drives using gears or pulley and belt assemblies have been described, yet any mechanical transmission means, such as toothed gears, chains and cogs, belts and pulley wheels, hydraulic drives and any combination thereof are thought to fall within the scope of the invention.

Similarly, embodiments have been described where the transmission means are inside the device. The man skilled in the art will readily find embodiments with off- centred drives, which are all to fall within the scope of the invention.