Waterwheels have long been used to convert some of the kinetic energy of flowing water into mechanical power via a turning axle. Originally, this rotation of the axle would often be used to directly drive adjacent machinery, but more recently waterwheels have also been used to generate electricity, and once installed, they do not produce any pollutants.

However, rivers and riverbanks are themselves sensitive habitats, and it is important that the installation has minimal impact on the immediate environment, as well as providing a waterwheel that efficiently utilises the flowing water of the river.

The present invention seeks to provide a folding structure that addresses these problems.

According to the present invention, there is provided a waterwheel assembly according to the independent claims. The invention will now be described, by way of example, with reference to the drawings, of which Figure 1 is a perspective view of the waterwheel;

Figure 2 is a side elevation of the waterwheel;

Figure 3 is a front elevation of the waterwheel;

Figure 4 is a perspective view of the waterwheel with a surrounding protective structure;

Figure 5 is a plan view of the waterwheel with a part of the surrounding protective structure;

Figure 6 is a front elevation of the waterwheel with a part of the surrounding protective structure; and

Figure 7 is a side elevation of the waterwheel with a part of the surrounding protective structure. Referring to figure 1, the waterwheel assembly 20 is supported by a concrete base 22 which is disposed on the top of a river bank (not shown). Two parallel spaced support beams 23, 24 extend from the concrete base 22 transversely to the river bank. The support beams 23, 24 may be formed from lengths of standard RSJ (rolled steel joist) I-beam. Two spaced parallel stringer beams 25, 26 extend perpendicularly between the support beams 23, 24. Two vertical posts 27, 28 extend upwards from the two stringer beams 25, 26, and these vertical posts 27, 28 are connected at their upper ends by a brace 32.

The waterwheel 35 is supported on an axle 30 that extends between the vertical posts 27, 28, supported by journal bearings (not shown) that allow the axle to turn. Two sets of radial spokes 42 are formed on the axle 30, each set of spokes 42 being reinforced by a circular rim 44. Where the ends of each spoke meets the rim, paddles 40 are set extending between the two rims. However, it will be realised that other forms of waterwheel could be used.

Two floats 37, 38 depend from the axle 30, each of the floats 37, 38 being secured by two arms 36 which are arranged triangularly, each arm secured to one end of the elongate form of each floats 37, 38, the two arms 36 meeting where they are secured to the axle, the axle being mounted in a bearing where it passes through the arms 38 so that the axle can freely rotate relative to the arms.

Each of the vertical posts 27, 28 includes a vertical channel 33, 34, these channels 33, 34 mnning most of the length of the vertical posts 27, 28. The axle and its journal bearing (and hence the waterwheel 35) are free to move up and down.

The axle 30 extends through the vertical post 28 nearest the river bank, and is torsionally attached to a power transfer means which in leads to a gearbox and generator 48; the power transfer means 63 may being flexible or articulated to accommodate vertical movement of the axle 30, as shown in figure . The waterwheel assembly 20 and concrete base 22 are located so that the flow of water of the river or waterway is perpendicular to the paddles 40 of the waterwheel 35. The weight of the waterwheel 35 is supported by an upward force from the floats 37, 38, which float partially submerged on the surface of the river. Since the axle 30 of the waterwheel 35 is free to move up and down the channels 33, 34 of the vertical posts 27, 28, the waterwheel rises and falls with any variation in height of the river. The waterwheel 35 and floats 37, 38 are arranged so that paddles 40 of the waterwheel 35 are optimally positioned to be efficiently extract kinetic energy from the flowing water.

By deposing this self-regulating waterwheel arrangement on in a cantilevered manner from the bank, the waterwheel can be quickly and efficiently installed in position, with no impact on the riverbed, and little impact on the river bank. Damning or modification of the river to create a race are entirely avoided.

Referring to figure 4, the waterwheel assembly 20 is surrounded by a protective structure 50 comprising slats 52 and cage 54, which also incorporates a walkway 56. The gearbox and generator 48 is enclosed within a gearing house 58. The protective structure 50 projects from the gearing house 58, and , a referring to figure 5, in plan view, the protective structure 50 forms three sides of a rectangle, so that the gearing house 58 and protective structure 50 completely encompass the waterwheel assembly 20. The walkway 56 is situated well above the normal water level of the river. Referring both to figure 4 and figure 7, the slats 52 extend vertically downwards from the edge of the walkway 56, to a depth beneath the lowest extent of the waterwheel 35. The slats 52 comprise a screen having vertical slots that allows water to pass through relatively unimpeded, but prevents branches and other debris that may be washed down the river and may otherwise becoming entangled with or damage the waterwheel 35. The cage 54 extends upwards from the edge of the walkway, the inner cage 62 projecting upwards from the inside edge of the walkway 56 and the outer cage 61 projecting upwards from the outside edge of the walkway 56. The outer cage 61 prevents unauthorised persons accessing the waterwheel assembly 20 from outside of the structure. The walkway 56 allows access via the gearing house 58 for authorised persons to walk around and inspect the waterwheel assembly 20. If necessary, the waterwheel 35 can be raised on lifting gear 59 in order to carry out maintenance. If required, the outer cage 61 could be extended higher, and even form a cage structure above the waterwheel assembly 20 to completely prevent unauthorised persons from climbing into the waterwheel assembly 20.

Figure 6 shows a view of the waterwheel assembly 20 and cage 54, without the slats 52. The articulated power transfer means 63 can be seen clearly here.