Field of the invention

The invention relates to a vertical axis power turbine comprising a plurality of support arms and a blade hinged on each of the support arms.

Background of the invention

Vertical axis wind turbines are usually used as power generating turbines and have the advantage that the main rotor shaft is oriented transverse to the wind direction, i.e. vertical. By doing so, electrical components such as a generator and gears need not be arranged in a nacelle at the top of a supporting construction in that the rotor shaft may extend down to the ground so that these components may be connected thereto from ground level. In order to function, the blades are arranged on radial arms such that they are perpendicular to the wind direction on one side of the turbine and parallel in relation to the wind direction on the other side of the turbine such that a pressure/force acting on the blades on one side of the turbine is larger in relation to the pressure/force acting on the blades on the other side of the turbine. This causes the turbine to rotate so that power may be generated e.g. by driving a generator. A problem with such wind turbines is that, when the wind speed is low, it is difficult to sustain the rotation as the blades may not be positioned properly. Thus, from WO 2018/109776 A1 a self- alignment mechanism is provided wherein stoppers are provided to aid in the self- alignment of the blades.

However, self-aligning mechanisms according to the prior art do not function if the wind is not blowing or if the velocity is so small so that the rotation cannot be sustained. Therefore, such a vertical axis wind turbine may not re-start if the turbine has stopped.

It is therefore an object of the present invention to provide for a more efficient self- aligning mechanism for a vertical axis turbine. The invention

The invention provides for a vertical axis power turbine comprising a plurality of support arms extending radially outwards from a hub where each of the support arms comprises a blade connected to a front side of the support arm through hinge means. This allows the blade to rotate in relation to the support arm in a horizontal plane. The hinge means is tilted in a tilt angle so that an upper end of the hinge means is arranged to be closer to the hub than a lower end of the hinge means. It is advantageous to provide the vertical axis power turbine with hinge means tilted in a tilt angle so that an upper end of the hinge means is arranged to be closer to the hub than a lower end of the hinge means in that the blade connected to the hinge means is also tilted in the tilt angle whereby the centre of gravity of the blade is off-set in relation to the hinge point. This is advantageous in that a turning moment around the hinge means is always present whereby the blade may always“close” or self-align again, i.e. move back so that the blade is substantially parallel with a longitudinal direction of the support arm if the flow of fluid has stopped or the fluid velocity is so small so that the wind turbine rotation is not sustained. And this is advantageous in that all the blades may move to a closed position regardless of their instantaneous position at the moment the turbine rotation stopped. And when all blades have moved back to a closed position, the turbine rotation may resume once the fluid flow is sufficiently strong again because none of the blades are left in a functionally inappropriate position so that the fluid force acting on the blades is not counter-acting the initialization of the rotation.

It should be noted that the“closed” position may be understood as the position at which force equilibrium is obtained when no fluid flows over the blade or the fluid velocity is negligible. In other words, the tilt angle of the hinge means is such that the force of gravity acting through the centre of mass of the blade is off-set in relation to the hinge means rotation axis so that the blade equilibrium position is the“closed” position. In this context, the term“hinge means” should be understood as a pin and socket hinge a hinge joint, ball joint, gate hinge, knuckle joint or any other type of hinge for connecting the blade to a front side of the support so that the blade may rotate in relation to the support arm in a horizontal plane, and which may be tilted in a tilt angle.

The“tilt angle” is to be understood as the angle between a center axis of the hinge means and a vertical plane. In an aspect of the invention, the tilt angle is between 0.2 and 30 degrees, preferably between 0.6 and 20 degrees, and most preferred between 1 and 10 degrees.

If the tilt angle is too small, the centre of gravity of the blade may not be sufficiently off-set whereby a weak“closing” effect is achieved, and if the tilt angle is too large, the centre of gravity of the blade may be too off-set whereby a strong“closing” effect is achieved so that a high velocity fluid flow is required to open the blade which limits the usability of the power turbine to such high velocity fluid flow which may not be advantageous as such a high velocity fluid flow may also result in large stresses on the vertical axis power turbine components. Thus, the above tilt angle ranges provide for an advantageous relationship between“closing” strength and material strength of the power turbine.

In an aspect of the invention, the vertical axis power turbine further comprises shock absorbing means arranged between the blade and the support arm of each support arm.

When the blade opens and closes repeatedly, any impact forces between the blade and support arm may be so large that they exceed the yield- or ultimate tensile strength of the material whereby the blade and/or support arm may be subject to premature failure. The repeated open and closing action may also initiate microcracks in the blade and/or support arm which may propagate to a critical size due to fatigue loads - again, resulting in a premature failure of the turbine. Thus, it is advantageous if the power turbine comprises shock absorbing means arranged between the blade and the support arm in that any impact forces between the blade and support arm are absorbed by such shock absorbing means whereby the blade and/or support arm are better protected from premature failure caused by high impact loads or cycling loading (fatigue).

In this context, the term“shock absorbing means” should be understood as foam material, an air cushion, a spring-damper mechanism, magnets, a hydraulic shock absorber or any other kind of shock absorber.

In an aspect of the invention the shock absorbing means comprises a blade magnet arranged on the blade and an arm magnet arranged on the support arm and wherein said blade magnet is arranged to face the arm magnet so that the polarity of the facing magnets is the same.

It is advantageous to provide a blade magnet arranged on the blade and with the same polarity as an arm magnet arranged on the support arm in that such a shock absorber is less likely to, over time, be worn down due to the repeated impacts between blade/ support arm and shock absorber. Furthermore, it is advantageous to use magnets in that the repelling magnetic force increases as the distance between the arm magnet and blade magnet decreases so that the deceleration of the blade, and thereby shock absorption, is smoother and more gradual. This is further advantageous in that the mechanical stresses on the components is reduced.

In an aspect of the invention, each of the support arms comprise a stop means for limiting the rotational movement of the blade.

It is advantageous to provide each of the support arms with stop means for limiting the rotational movement of the blade in that large mechanical loads on the hinge at too large rotational position of the blade is avoided. Furthermore, it is advantageous in that the blade may not rotate to an inappropriate position, e.g. a back side of the support arm where the principle of the vertical axis power turbine according to the invention would cease to work.

It should be emphasized, that the term“stop means” should be understood as a fixed post, a wire, a folding mechanism or any other type of stopper for limiting the rotational movement of the blade.

In an aspect of the invention, the hinge means is also tilted so that the upper end of said hinge means is tilted away from the front side of the support arm.

It is advantageous to tilt the upper end of the hinge means away from the front side of the support arm in that the blade thereby leans“backwards” so that the closing effect is enhanced in that the gravitational force acting through the centre of mass further aids in moving the blade to the closed position.

It should be noted that the direction, in which the upper end of the hinge means is tilted, is such that an upper end of the blade is tilted towards the direction in which it moves during normal operation.

In an aspect of the invention, each of the support arms comprise a telescopic mechanism for adjusting the length of the support arms.

During operation, the blades follow a circular path around the vertical axis of the power turbine. The circumference of this circular path is determined by the support arm length (i.e. the radius of the circular path). For a given angular velocity of the hub (i.e. rate of rotation), the blades spend a given amount of time in moving from one point to another point located 180 degrees on the other side of the circular path. During this movement, the blade position changes from a perpendicular/parallel position (in relation to the fluid) to a parallel/perpendicular position. If the support arm is long, the time distance between the two points is increased (larger circle) and if the support arm is short, the time distance between the two points is decreased. The consequence of a short time distance between the two points is that the blade must quickly alternate between one position to the other and thereby large accelerations on the power turbine components (blade, support arm, hub and other components) are present which in turn result in large stresses. Thus, it is advantageous if the support arms comprise a telescopic mechanism in that the length of the support arms, and thereby the time available to switch between parallel/perpendicular position of the blade may be adjusted by the telescopic mechanism.

Furthermore, adjusting the length of the support arm is advantageous in that the rotational speed of the hub may be controlled. And since the hub may be connected to a generator, it is advantageous to be able to control the hub rotation speed so that it is adjusted to a specific range of rotation speed where the efficiency of the generator is largest.

In in aspect of the invention, each of the support arms comprise rotation means.

It is advantageous if the support arms comprise rotation means in that it enables for the support arm to rotate so that the blade is rotated to a position in which it is horizontal whereby the blades are not driven by the flow so that it is out of operation. This functionality is advantageous in situations where the fluid velocity is so large that the risk of damage being inflicted on the turbine is so high that the turbine should be stopped or if the operator simply does not desire to operate the power turbine (e.g. during service, use of alternate power sources, shut-down or other reasons).

In this context, the term“rotation means” should be understood as a revolute joint, a bearing construction, a bushing, a gear mechanism, a pulley system, a wire system, a cam mechanism, a spring actuated mechanism or any other type of rotator. In an aspect of the invention, the support arms are slanted upwards in an angle of between 1 and 5 degrees in relation to horizontal.

If the support arms are slanted too much upwards, the added self-aligning“closing” effect of the blades may be so strong that it requires a strong fluid flow to“open” the blades again (i.e. the turbine only sustains the rotation in high velocity fluid flow) and if the support arms are only slightly slanted upwards, the added self-aligning“closing” effect may not be sufficiently strong. Thus, the above-mentioned range reflects an advantageous relationship between functionality and usability.

In an aspect of the invention, the vertical axis power turbine further comprises a locking mechanism for locking the movement the blade in relation to the support arm.

If the vertical axis power turbine is stopped, e.g. for service, it may not be desirable that the blades are freely hinged so that the blade may flutter back and forth on the support arm. Such fluttering may damage the blade itself or induce vibrations on the entire turbine so that other parts are damaged. Therefore, it is advantageous to be able to lock the position of the blades so that the blades and/or other parts of the turbine are not damaged.

In an aspect of the invention, the blade comprises guide vanes protruding from a front side of said blade.

It is advantageous to provide the blade with vanes protruding from a front side of the blade in that the fluid flow is directed more efficiently over the blades.

In an aspect of the invention, the blade is hinged on said hinge means so that the centre of mass of said blade is closer to said hub than said hinge means when a blade back side is facing said support arm front side. It is advantageous to hinge the blade on the hinge means so that the centre of mass of the blade is closer to the hub than the hinge means in that it is ensured that the“closing” effect is always present, i.e. the blade will always have a tendency to move back to the closing position where the blade back side is facing the support arm front side.

In an aspect of the invention, the vertical axis power turbine further comprises a generator directly coupled to the hub.

It is advantageous to couple the generator directly to the hub in that no energy is lost in a transmission between the generator and the hub.

In an aspect of the invention, the tilt angle is determined based on a mass distribution and/or dimensions of the blade.

Analysing the blade design using engineering mechanics, one may realize that the tilt angle influences the self-aligning“closing” effect of the blade. More specifically, the tilt angle is related to and therefore determined based on the position of the centre of mass and therefore the mass distribution and/or dimensions of the blade. Using first moment of area provides for an easy method for determining the centroid of an area (i.e. it is based purely on the spatial distribution of the shape) and if the blade mass distribution is homogenous (i.e. the blade mass is evenly distributed over the spatial extension of the blade), the centre of mass also corresponds to the centroid. Thus, in a simple body with evenly distributed mass, the centre of mass (and therefore the tilt angle) may be determined solely based on the first moment of area, i.e. the blade dimensions. However, if the mass is not uniformly distributed across the blade, the centre of mass does not correspond to the centroid. In such a body, the centre of mass is offset in relation to the centroid and therefore the mass distribution must be used to determine the ideal tilt angle for such a blade. Hence, it is advantageous to use the mass distribution and/or the dimensions of the blade to determine the tilt angle in that the exact tilt angle for providing the optimal self-aligning“closing” effect may be determined so that the closing effect is not“too strong” or“too weak” which it could be by mistake if the tilt angle is erroneously calculated based on, for example, only the dimensions of a blade.

The sources to the non-uniform mass distribution across the blade could be manufacturing imperfections, varying thickness across the blade, external components or parts attached to the blade or other.

In an aspect of the invention, the blade comprises slide means on the back side of the blade for sliding the blade in relation to the hinge means.

It is advantageous to provide the blade back side with slide means so that the blade may slide in relation to the hinge means in that the position of the centre of gravity in relation to the hinge means may be adjusted without dismantling the blade from the support arm.

It should be noted that the term“slide means” should be understood as a slit, telescopic mechanism, piston, or other type of slider for allowing the blade to slide in relation to the support arm.

In an aspect of the invention, the vertical axis power turbine according any of the previously discussed vertical axis power turbines is used for generating power.

It is advantageous to use a vertical axis power turbine according to any of the previously discussed power turbines for generating power in that such a vertical axis power turbine is well-suited for efficiently generating power and that its rotation is self-sustained even if the flow of fluid has temporarily stopped. Figures

The invention will be described in the following with reference to the figures in which fig. 1 illustrates a vertical axis power turbine as seen in perspective, fig. 2 illustrates a vertical axis power turbine as seen from above, fig. 3 illustrates a vertical axis power turbine as seen from the side, fig. 4 illustrates a close-up view of the hinge means as seen in perspective, and fig. 5 illustrates a close-up view of the hinge means as seen from above.

Detailed description

Fig. 1-3 illustrates a vertical axis power turbine 1 as seen in perspective, from above and from the side, respectively.

In fluid mechanics it is known that a large surface moving through a fluid (or a stationary object acted upon by a fluid) results in drag force, also called air resistance, fluid resistance, fluid friction or other. Although it is oftentimes desired to lower the drag force (race cars, aircrafts, rockets and other), in some applications it can be beneficial to increase the drag force such as in parachutes, water mills and also in the blades 4 of a vertical axis power turbine 1 as shown in fig. 1. The drag on such an object may be (roughly) calculated by using the drag equation, which is given by: Where p is the density of the surround fluid (e.g. air or water), v ² is the square of the fluid velocity, A is the cross-sectional area of the object (as measured perpendicular to the direction of movement/fluid direction) and C _D is the dimensionless drag coefficient. As is evident from the above equation for constant fluid velocity and density, the area and drag coefficient may be adjusted to increase or decrease the air resistance.

In this embodiment, the blades 4 are of rectangular shape. However, in another embodiment, the blades 4 could be triangular, circular, polynomial or other kind of shape. In another embodiment, the blades 4 could also be of more complex shapes such as a half-sphere, bucket, shovel or a cone or other shape which could be used as a surface for providing large fluid resistance when a fluid flows over the blade 4. The blade could also comprise surface reduction means, e.g. in the form of a folding structure which may be adjusted so that the cross sectional area (i.e. the area perpendicular to the fluid flow and which provides for the fluid resistance) may be adjusted. This could be performed e.g. by a series of lamellas which may be pivoted so that more or less fluid flow may flow through such a blade. The blade could also comprise an aperture which may be adjusted so that the fluid resistance is reduced or increased according to the size of the aperture. The surface reduction means could comprise pivot arms, cords, wires, rods or other type of mechanical structure which interacts so that the blade area may be adjusted e.g. by folding or unfolding. The fluid resistance could also be adjusted by adjusting the overall size of the blade. This could be performed by a structure which may bend and fold according to the fluid resistance or remote input.

Thus, in an embodiment of the invention, the blade cross sectional size may change according to the fluid speed. This is advantageous in that the blade may be designed so that the fluid resistance does not exceed an upper limit which may damage the blade, or which may result in a large rotation speed of the power turbine which may damage other components. Also, in this embodiment, the material of the blade 4 is steel. However, in another embodiment, the construction material of the blade could be aluminum, titanium, a polymer material, a carbon fiber material, a glass fiber material, cloth material, or any other type of material.

As shown on fig. 1, the blades 4 on the right side of fig. 1 are perpendicular to the wind direction (indicated by the arrows W). In this configuration, the area and the drag coefficient are larger than if the blades 4 are arranged parallel to the wind direction as is the case for the blades 4 on the left side of fig. 1. Hence, according to the above formula, the air force/pressure acting on the right-side blades 4 is larger than the air force/pressure acting on the left-side blades 4 which in turn causes the wind turbine to rotate in a (in this illustration) in a counter-clockwise direction (as seen from above). As the hub 3 rotates in a counter clock-wise direction, the blades 4 will start to rotate around the end of the support arm 2 such that it“swings out” due to the hinge point and centrifugal force and thereby move towards a position in which it is parallel to the wind W as shown on the left side of the vertical axis power turbine 1. This alternating position of the blade 4 sustains the rotation of the vertical axis power turbine 1 as long as there is a flow of water/air and thereby production of power by driving the generator 14.

However, if the wind ceases to blow, the blades 4 will automatically“close” due to the way the hinge means 6 are arranged on the support arm 2. More specifically, the upper end 6a of the hinge means 6 is arranged closer to the hub 3 than the lower end 6b. The effect of this is that the center of gravity is offset so that the gravity force acting through the center of gravity results in a turning moment so that the blade 4 moves to a“closed” position in which the blade 4 is substantially parallel to the longitudinal direction of the support arm 2 (also the position in which the blade 4 is regarded as perpendicular to the wind direction). If the wind starts to blow again, the blades 4 on the left side (as seen from above and in relation to the wind direction) will start to“open” while the blades 4 on the right side will remain perpendicular to the wind direction (see fig. 2 where the vertical axis power turbine is shown from above). This is possible because the blade 4 is hinged on the hinge means 6 slightly offset to the center (as seen from above) whereby, when the wind blows, a turning moment is obtained around the hinge means 6 such that the blade 4 may“open”. Since the blades 4 are hinged on a front side 2a of the support arm 2 the support arm 2 prevents the blades 4 on the right side from“opening” because the blade 4 is pushed against the front side 2a of the support arm 2. In this way, the rotating motion may be re-started after the wind turbine rotation has completely halted due to lack of wind.

In this embodiment, the support arms 2 are rectangular bars. However, in another embodiment, the support arms 2 could be rods, I-beams, lattice construction, circular beams or other type of support structure which can withstand the bending and shear loads from the wind acting on the blades 4 as well as the weight of the blades.

In this embodiment, the telescopic mechanism comprises of at least two parts of the support arm 2 arranged to slide in relation to each other so that the total length may be adjusted. The at least two parts may be interlocked with a locking pin, carabiner, pull pin, bent arm pin, cotters, spring biased locking mechanism or other type of locker for locking the mutual position of the at least two parts of the support arm when the length has been adjusted. In another embodiment, the telescopic mechanism may also comprise a hydraulic cylinder, hydraulic/pneumatic actuator, piston, telescopic joint or other type of mechanism for adjusting the length of the support arm(s) 2.

In this embodiment vertical axis power turbine 1 is positioned on the roof of a private property (not shown). However, in another embodiment, the vertical axis power turbine 1 could be positioned on a tall hill, open terrain or under water. For example, the vertical axis power turbine 1 could be placed in a river, stream or in the ocean. The advantage of placing the vertical axis power turbine 1 in such places is that the flow of fluid is substantially steady as the direction of flow is substantially constant If the wind is blowing hard, the blades 4 may swing back and forth with such force that the blades 4 and/or the support arms 2 may be damaged due to the impact force. Therefore, in this embodiment a shock absorbing means 7 is arranged between the blade 4 and the support arm 2. In this embodiment, the shock absorbing means comprises a blade magnet 8a arranged on the back side 4b of the blade and an arm magnet 8b arranged on the support arm 2. However, in another embodiment, the shock absorbing means 7 could be a piece of foam material attached to the support arm 2 and/or the blade 4, an air cushion, a spring-damper mechanism, a hydraulic shock absorber or other type of shock absorber for limiting the impact force between the blade 4 and support arm 2. Furthermore, in this embodiment the shock absorbing means 7 is arranged on the support arm 2 instead of the blade 4 to reduce the inertia of the blade 4. In another embodiment, the shock absorbing means 7 could be connecting the support arm 2 and blade 4, for example if a hydraulic shock absorber were used. In such an arrangement one end of the shock absorber could be attached to the support arm 2 and the other could be attached to the blade 4 whereby the shock absorber may dampen the blade 4 if necessary.

In an embodiment, the shock absorbing means 7 could be arranged on the stop means 9 as this would provide a point of impact and therefore a reasonable position to arrange the shock absorbing means 7.

Furthermore, in another aspect of the invention the vertical axis power turbine 1 may be provided with rotation means 11 on the support arms 2 or hinge means 6 for rotating the blade 4 around a longitudinal axis of the support arm 2 so that the blade 4 is rotated to a position in which it is horizontal. In this embodiment, the rotation means 11 is a rotating actuator. However, in another embodiment, the rotating means 11 could comprise a revolute joint, a bearing construction, a bushing, a gear mechanism, a pulley system, a wire system, a cam mechanism, a spring actuated mechanism, or any other type of rotation means 11 for rotating the support arms 2 so that the blades 4 are rotated to a horizontal position. Also, in this embodiment, the rotating means 11 are coupled so that the support arms 2 are rotated simultaneously. However, in another embodiment the support arms 2 could be rotated independently from each other. The rotating means 11 could be remote actuated e.g. from a user using a smartphone, computer, remote control or other kind of device for remote controlling the rotating means 11. The rotating means 11 could also be controlled automatically (individually or simultaneously adjusting all at the same time) e.g. by automatic adjustment to power demand, to mechanical loads (e.g. to prevent the turbine from overloading), to weather forecast information supplied to the power turbine 1 (e.g. from a network of sensors on the turbine, database, internet communication with external weather forecast source) or other kind of information which could be used to automatically control the rotation means 11.

The rotation means 11 could also be arranged on the hinge means 6 so that the blades 4 could be rotated on the hinge means 6 without rotating the support arms 2.

To further aid in controlling the blade 4 movement, stop means 9 are, in this embodiment, arranged on the support arm 2. And in this embodiment, the stop means 9 is a simple pin protruding from the support arm 2 at a specified angle and length so that the opening of the blade 4 is limited to a certain opening angle b (angle between blade back side 4b and support arm front side 2a), e.g. 100 degrees, but could also be 95, 120 or 130 degrees. In another embodiment, the stop means could be a wire of a certain length connecting the blade 4 and the support arm 2 so that the wire length naturally limits the opening of the blade 4. It could also be a folding structure (e.g. similar to a folding ruler), which folds upon opening of the blade 4 so that the final folded-out form stops the blade 4 from further opening. In yet another embodiment, the stop means 9 could be a spring connecting the blade 4 and the support arm 2, the spring being dimensioned such that the spring force at a certain spring extension (which would be an unavoidable consequence of connecting the blade and arm) is so large that the blade 4 is restricted from further opening. An elastic cable or rubber band could also be used in similar way so as to function as a stop means to limit the position of the blade 4 to a certain opening angle b.

For locking the position of the blade 4 in relation to the support arm 2 the turbine 1 may comprise a locking mechanism 12 which in this embodiment comprises a bolt 12. However, in another embodiment, the locking mechanism 12 could be a hook and pawl mechanism, spring biased locking mechanism, actuator, gear mechanism or other type of locking mechanism for locking the position of the blade 4 in relation to the support arm 2.

To further improve the efficiency of the vertical axis power turbine 1, the blades 4 may comprise guide vanes 13, which in this embodiment are static, horizontal plates protruding from the blade front side 4a. However, in another embodiment, the guide vanes 13 could be tilt able so that the fluid dynamic influence may be adjusted. The guide vanes 13 may also be automatically adjustable to the wind/water flow direction W. This could be achieved by a control algorithm calculating the optimum position of the guide vanes 13 depending on the position, size and shape of the blade 4 and the instantaneous flow direction.

Fig. 4 and 5 illustrates a close-up view of the hinge means 6 as seen in perspective and from above, respectively.

The blade 4 is connected to the support arm 2 via the hinge means 6, which in this embodiment comprises a pin and socket hinge where the sockets are arranged on the back side of the blade 4 and the pin is arranged on the support arm 2, but could also be inverted so that the blade 4 comprises the pin and the support arm 2 comprises the socket for receiving the pin. In another embodiment, the blade 4 could be connected to the support arm 2 by means of a hinge joint, ball joint, gate hinge, knuckle joint or other type of hinge. In an embodiment, the hinge means could comprise a fluid bearing, i.e. a bearing wherein the fluid provides for a damping effect which in turn results in an increased resistance as the rate of rotation of the bearing increases (examples of such a fluid bearing is a hydrostatic or hydrodynamic bearing). The fluid in the fluid bearing could be a Newtonian fluid, a non-Newtonian fluid, shear thickening fluid (also referred to as a shear-thickening fluid) or other type of fluid so that the rotation resistance increases with viscosity of the fluid, shearing, rotation speed, temperature, pressure or other parameter. By using such a fluid bearing, the shock absorbing means may also be integrated in the bearing which is advantageous in that a separate shock absorbing means is redundant so that the power turbine is simpler and cheaper.

The sliding means 15, which in this embodiment is a hollow rectangular bar with a track in which the hinge means may slide along is arranged so that the horizontal position of the blade 4 in relation to the support arm 2 may be adjusted. However, in another embodiment, the sliding means may comprise a slit arranged in the blade for receiving e.g. a bearing, or any other sliding mechanism. The sliding means 15 may also be arranged to adjust the vertical position of the blade 4 in relation to the support arm. This could be implemented in a similar way as previously mentioned.

As shown in fig. 4 the hinge 6 is slightly tilted so that the upper part 6a is closer to the hub (not visible in this figure) so that the hinge means forms a tilt angle a between the hinge axis of rotation (indicated by that dash-dotted line) and a vertical plane.

In an embodiment, a remote control may be used to e.g. control the tilt angle a and length of each of the support arms 2.

The invention has been exemplified above with reference to specific examples of support arm 2, blade 4, shock absorbing means 7 or other. However, it should be understood that the invention is not limited to the particular examples described above but may be designed and altered in a multitude of varieties within the scope of the invention as specified in the claims. List

1. Vertical axis power turbine

2. Support arm

2a. Support arm front side 3. Hub

4. Blade

4a. Blade front side

4b. Blade back side

6. Hinge means

6a. Upper end of hinge means

6b. Lower end of hinge means

7. Shock absorbing means 8a. Blade magnet

8b. Arm magnet

9. Stop means

10. Telescopic mechanism

11. Rotation means

12. Locking mechanism

13. Guide vanes

14. Generator

15. Slide means

a. Tilt angle

b. Blade opening angle HP. Horizontal Plane

W. Wind direction