Patent GB-823479-A (GB)
Title: Improvements in and relating to windmills
IPC: F03D7/02
Filed: 1957-08-26
Abstract: 823,479. Wind motors. MONO PUMPS Ltd. Aug. 26, 1957, No. 26898/57. Class 110 (3). A windmill comprising a plurality of radial vanes of curved cross-sectional shape mounted on a substantially horizontally disposed shaft, has each vane pivotally mounted in a longitudinal sense on a radial spoke with resilient means against the action of which the pitch or angle of incidence is automatically varied in response to wind speed and each vane formed with a concave face which varies progressively from maximum depths at the inner ends to minimum depths at the outer ends while the mean angle of incidence increase progressively from the inner to the outer ends. A substantially horizontal shaft 10, which is preferably at 3 degrees to the horizontal and points in the rearward direction, carries a flange 12 having a forwardly pointing extension 13. The flange 12 forms a hub for a number of radial spokes 14 stabilized by oblique spokes 15. The spokes 15 may be arranged forward of or in the rear of the spokes 14. The weight of the rotor may be balanced by a counterweight on the other side of the vertical shaft on which the windmill may rotate into the wind. Tie rods 20 ensure the proper spacing of the spokes 14. Each blade or vane 23a is mounted on a spoke 14 by means of a tubular sleeve 22 attached to the vane preferably by transverse bars 24. Fixed collar 25 on the spokes 14 prevent axial movement of the sleeve 22. Helical springs 44 restrain the pivoting action of each vane. The vanes are mounted asymmetrically on the spokes 14 so that the pitch or angle of incidence varies with the wind pressure. A weight 26, Fig. 11, mounted on a lever 27 pivoted on a spoke 14, moves outwards under the action of centrifugal force and by means of a link 28 changes the angle of incidence of the vane. Alternatively, the link 28 may extend to an adjacent vane. All the vanes 23 are connected to move simultaneously by links 29. A weight 26 is provided on at least one spoke but preferably at least two weights on opposing spokes are employed. In a modified form of construction, Fig. 9 (not shown), the or each centrifugally controlled weight is slidable inside a tubular casing mounted on the outer end of a spoke 14 or spoke stay 15. The weight is connected by a rod to a vane synchronizing unit 34, Fig. 13, comprising a flange 36 supporting tubular elements 37 connected by L-shaped elements 38 to sleeves 39 attached to the vanes. The governor weights may be attached to the connecting rods the ends of which will then slide in locating elements attached to the spokes. If desired, each tubular sleeve 22 may move axially on the spokes 14 against the action of a helical torsion spring 44. The weight of the sleeve and vane then may form the governor weight. Stop means may be provided on the hub flange 12 to limit the pitch variation of the vanes. The vanes may converge in the outward or inward direction. Each vane is shaped with the longitudinal leading edge 46 well concaved at the end nearest the wheel hub while the trailing edge 47 at this point is almost flat. Towards the outer end 48, the concavity becomes progressively less leading almost to a straight edge at the periphery. The mean angles of incidence at the opposite ends of the vanes increase progressively from the inner to the outer ends.