TURBINE DEVICE FOR DRIVING GENERATORS ON SAILING BOATS

Abstract: A turbine device for driving a generator on sailing boats, consisting of a housing (10) with a turbine wheel (11, 20, 21) at one end, a tubular rigid member (17) fixable to the hull of the boat and supporting the housing (10) below the surface of the water, a bevel (16) disposed in the housing (10) and having an input shaft (12) which supports the turbine wheel (11, 20, 21), and an output shaft (19) mounted in the tubular member (17) and connected to a generator. A ring (21) which is coaxial with the centre axis of the housing (10) is mounted around the blades (20) of the turbine wheel (11, 20, 21) and has the general shape of a truncated hollow cone, preferably with a wall which in section has the profile of an airfoil, to maximize the flow through the turbine wheel.

Description: TURBINE DEVICE FOR DRIVING GENERATORS ON SAILING BOATS The present invention relates to a turbine device for driving generators on sailing boats. In smaller sailing boats, for instance of a length of 7-10 m, it is necessary to install either batteries or a motor-driven generator to produce the energy required for instance for lanterns, lamps on instrument panels etc. The batteries are disadvantageous because it is necessary constantly to check the charge of the batteries and, also, the required minimum capacity means that they are heavy and expensive. A motor-driven installation is noisy and requires maintenance. Thus, sailors have long felt a need for a simple device for generating the energy absolutely necessary, preferably with the aid of a battery, and the object of this invention is to provide such a device which is silent, easy to mount and relatively inexpensive. According to the invention, this object is achieved by means of a turbine device which consists of a housing with a turbine wheel at one endt a tubular elongate rigid member which is detachably fixable to the hull of the boat and which, at one end, supports the housing with the turbine wheel below the water surface; a bevel gear enclosed in the housing dnd having an input shaft which supports the turbine wheel, and an output shaft which is connected to a transmission shaft mounted in the tubular member and connected to the generator; and a ring substantially with the general shape of a truncated hollow cone which is mounted around the blades of the turbine wheel coaxially with the centre axis of the housing with its larger diameter closest to the housing to maximize the flow through the turbine wheel. The invention will be described in greater detail hereinbelow with reference to the accompanying drawings which show an embodiment of the invention. Fig. 1 is a side view partly in section of a turbine device according to the invention. Fig. 2 shows the device of Fig. 1 from above. Fig. 3 shows the device of Figs. 1 and 2 from in front, and Fig. 4 shows the section and pitch of the turbine blades at different distances from the centre axis of the turbine hub. In Fig. 1, there is shown a housing 10 which is made of a suitable plastic material and tapers towards both ends. At a distance from the left-hand end in the drawing, the housing 10 is squarely cut off and its forward portion forming a turbine wheel hub 11 is non-rotatably mounted on a shaft 12 which extends into a cavity in the housing 10. Fixing plates 14 are connected to the inner walls of the cavity 13. Two of the plates 14 have registering openings which are coaxial with the longitudinal centre axis of the housing 10 and are provided with ball bearings 15, by means of which the shaft 12 of the turbine wheel is rotatably mounted in the housing 10. As appears from the figure, further ball bearings may be provided, if so required. A gear wheel which is part of a bevel gear generally designated 16 is non-rotatably mounted on the shaft 12 in the cavity 13. This gear wheel meshes with the other gear wheel of the bevel gear through an oblique toothing. Said other gear wheel is mounted at the end of a shaft 19 which is the output shaft of the bevel gear-and which is disposed at right angles to the shaft 12. The shaft 19 extends through a tube 18 which is disposed in a streamlined elongate casing or member 17. The shaft 19 rises to a generator (not shown). The elongate member 17 constitutes the supporting structure of the turbine device and is intended to be secured to a suitable part of the sailing boat, preferably the stern. As appears from Fig. 1, the hub 11 carries the turbine wheel which consists of four blades whose angle of pitch with respect to the longitudinal direction of the hub changes according to Fig. 4 illustrating the blades in cylinder section. It appears that the pitch of the blades decreases with increasing diameter and also that the thickness of the blades decreases with increasing diameter. Of decisive importance is the ring 21 which is connected to the ends of the blades 20 facing away from the hub 11. The ring 21 is in the form of a truncated hollow cone with its larger diameter facing rearwardly towards the housing 10. In cross-section, the ring 21 has the profile of an airfoil. According to Fig. 3, the free ends of the turbine blades are inserted in the ring 21. This method of connecting. the ring 21 with the blades has proved advantageous in actual practice, but it is of course possible to mould the hub, the blades and the ring as an integral piece. To connect the device according to the invention to the boat, this can have a fixing device which consists of a plate with four bolt holes and a tubular sleeve with two clamping screws, and of a tube with a tubular sleeve with two clamping screws.The latter tubular sleeve is placed around the tube 18 surrounding the output shaft 19 of the bevel gear. With a fixing device of this type, the device according to the invention can be applied to the stern of most ships' hulls independently of the inclination of the stern or freeboard height. As appears from the above, the main object of the invention is to drive a generator for-generating electric current, but by equipping e.g. the shaft 19 between the bevel gear 16 and the generator with a transducer and providing a suitable electric or mecanical sensing device for the transducer, the turbine can also be used as a patent log for indicating speed and the distance sailed. The major part of the device according to the invention is made of a plastic material, preferably reinforced plastic, but certain parts may consist of metal, for instance the fixing plates and ball bearings. In a practical embodiment, the elongate member 17 has a length of 1,000 mm and the turbine wheel a diameter of 140 mm. A useful power is obtained within a speed range of from 4 to 7 knots. For instance, at a speed of 6 knots, a power of 41 W at 15 V and 2.7 amp delivered from the generator has been measured. Maximum efficiency should be about 70 %, which means a power output from the generator of 55-60 W at a speed of about 6 knots. This power is clearly sufficient for charging a battery which, in turn, supplies lanterns, lamps on instrument panels etc with current. By the simple measure of mounting the device according to the invention on the hull of the boat in the manner indicated above and connecting the output of the generator to the battery circuit, the battery will always be kept charged.

Claims: CLAIMS 1. A turbine device for driving generators on sailing boats, c h a r a c t e r i z e d by a housing (10) with a turbine wheel (11, 20, 21) at one end; a tubular elongate rigid member (17) which is detachably fixable to the hull of the boat and which, at one end, supports the housing (10) with the turbine wheel (11, 20, 21) below the water surface; a bevel gear (16) enclosed in the housing (10) and having an input shaft (12) which supports the turbine wheel (11, 20, 21), and an output shaft (19) which is connected to a transmisson shaft mounted in the tubular member (17) and connected to the generator; and a ring (21) with the general shape of a truncated hollow cone which is mounted around the blades (20) of the turbine wheel coaxially with the centre axis of the housing (10) with its larger diameter closest to the housing (10) to maximize the flow through the turbine wheel. 2. Turbine device as claimed in claim 1, c h a r a c t e r i z e d in that the housing (10) and a turbine wheel hub (11) mounted on the input shaft of the bevel gear, together form a smooth body tapering towards its opposite ends. 3. Turbine device as claimed in claim 1 or 2, c h a r a c t e r i z e d in that the wall (21) of the ring, in sectional view, has the profile of an airfoil. 4. Turbine device as claimed in claim 1, 2 or 3, c h a r a c t e r i z e d in that a device consisting of a transducer on the output shaft (19) of the bevel gear, a mecanical or electric sensor and a converter is adapted to indicate the speed of the boat and the distance sailed.

Inventors: HARDESTAM, BROR GUSTAV HERMAN, Härdestam, Bror Gustav Herman, NILSSON, JOHN ERIK VALTER
Applicants: HARDESTAM BROR GUSTAV H, NILSSON JOHN ERIK VALTER
Application year: 1984
Main classification: B63J3
IPC codes: B63J3