Abstract:
A wind energy converter includes a support arm or post rotatably mounted on a base and having an upper free end; a pivot arm is pivotally mounted on the free end and has an end remote from the support arm; a pair of vanes are mounted on a pivot rod carried at the end of the pivot arm so that the vanes are free to rotate about the pivot rod; abutment arms are provided on the end of the pivot arm to limit the arc through which the vanes may rotate; at the other end of the pivot arm a linkage structure is provided to connect the other end of the pivot arm to an electrical generator.

Description:
This application claims the benefit of Provisional Application No. 60/279,773, filed Mar. 30, 2001. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to wind energy converters and, more specifically, to a greatly simplified wind driven converter for use with an electrical generator of conventional construction. The present invention is more particularly characterized by a low initial cost and good efficiency over a greater range of wind velocity. The device is also distinguished in the simplicity of its structure and its reliability over an extended interval before requiring servicing. 
     BACKGROUND OF THE INVENTION 
     With the increasingly stringent regulations governing the use of fossil fuels to generate power, alternative sources of electrical power such as solar and wind power are becoming increasingly economical and attractive to the marketplace. In addition, in many remote areas in this and other countries, alternative sources of electrical power are becoming a necessity with increasing population density in such remote locations. However, as is frequently the case, the more remote the location, the more destitute are the inhabitants likely to be thus making an investment in alternative power generation on a scale so as to make it profitable or sufficient to meet the anticipated needs very improbable. 
     The prior art has proposed a large number of different structures for making use of a wind energy to generate electrical power. The structures have generally been complicated to install and difficult and expensive to maintain over long periods of time in view of the large number of moving parts that are required. In other arrangements, efficient operation could only be achieved where the velocity of the wind current averaged at a relatively large magnitude. This made the structures useful in only a relatively few locations. Typically, the designs of the prior art involved the construction of a windmill mounted at a selected height above the ground or structure on which it is supported. The rotary output of the windmill is usually connected to a crankshaft adapted to rotate a conductive coil or primary windings in a magnetic field in order to generate current in the secondary windings of the generator. Windmill structures typically are balanced annulus shapes thereby offering little if any mechanical advantage to overcome the weight of the primary windings of the generator together with the weight of the connecting linkages. As a consequence, it has frequently been necessary to construct the windmill with relatively large surface area vanes. As a consequence, the expense of construction has often been adversely affected. 
     SUMMARY OF THE INVENTION 
     The structure of the present invention greatly simplifies the operation of the surfaces interacting with the wind current thereby substantially reducing the cost of construction and greatly simplifying the maintenance required for the apparatus. In one embodiment, a post is mounted on a table about which the post is free to rotate to enable the apparatus to align itself favorably with the prevailing wind direction. The post supports adjacent one end a pivot arm pivotally mounted adjacent one end of the pivot arm. The remote end of the pivot arm supports at least one and preferably a pair of airfoil shaped vanes, which are mounted on a pin or rod extending through the pivot arm so that the pin will be at right angles or perpendicular to a plane in which the pivot arm will move in operation. Preferably, the vanes are eccentrically mounted on the pin or rod in a manner to favor movement into the wind. 
     The opposite end of the pivot arm is connected through a linkage to an input shaft of an electrical generator of conventional construction. In addition, motion limiting structure is carried by the pivot arm to limit the degree of pivoting that the vane or vanes are permitted. This will assure that the vanes assume an angular position relative to the wind flow that will cause the pivot arm to move from one limit position through an arc to an opposite limit position whereupon the position of the vanes changes to move the pivot arm back to its original position to repeat the cycle. With this arrangement, reliable operation over an extended period will be far less expensively achieved compared with the windmill structures common to the prior art. 
     The forgoing and other advantages will become apparent as consideration is given to the following description taken in conjunction with the accompanying drawings, in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view in elevation of one embodiment of the present invention illustrating various dispositions of the pivot arm in operation; 
     FIG. 2 is a top plan view of the apparatus of FIG. 1; 
     FIG. 3 is in view similar to FIG. 1 but showing a different embodiment of the present invention; 
     FIG. 4 is a detailed schematic view of a crank connection to an electrical generator useful with the present invention; and 
     FIG. 5 is alternate embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings, wherein like numerals designate corresponding parts throughout the several views, there is shown in FIG. 1 a schematic illustration of the apparatus of the present invention generally designated at  10 . The apparatus  10  includes an upright post or arm  12  which is rotatably mounted on a table  14  which may rest on a building roof or the ground. It is not essential that the post  12  extend vertically as will be apparent from the following description. At the top uppermost point  20  of the post  12 , a pivot pin or rod  18  is provided and, for this purpose, the upper end  20  of the post  12  is bifurcated as shown more clearly in FIG.  2 . The pivot arm  16  extends beyond the pivot pin or rod  18  to an opposite end  28 . The other end of the pivot arm  16  is provided with a pin or rod  24  which extends through the arm  16  preferably using a tubular bearing and, in a preferred embodiment, the pin  24  is attached fixedly to two airfoil shaped vanes  22  and  23 . In this embodiment, the vanes  22  and  23  will rotate in unison by virtue of the rigid connection to the pivot pin  24 . In another embodiment, the connection to the pivot can  24  need not be rigid so that the vanes  22  and  23  will be free to rotate about the pin  24  independently. In a preferred form, the vanes  22  and  23  are mounted so that length a as shown in FIG. 3 is greater than length b on the opposite side of the pivot pin  24  or  24 ′. It is also preferable from an efficiency standpoint that the weight distribution of the pivot arm  16  be balanced about the pivot axis  18  and  18 ′ and for this purpose, weight may be attached to the opposite end  28  so that the pivot arm  16  in the absence of any wind current will extend substantially horizontally to the ground. 
     As thus far described, it will be understood that the pivot arm  16  is preferably constrained to pivot through an arc generally designated  26  and the operation of the vanes  22 ,  23  will be effective to cause oscillating motion of the pivot arm  16  between the two extreme positions as shown in FIG. 1 in broken lines. A number of alternative mechanical devices may be employed to restrain rotational motion of the vanes  22 ,  23  in use and one such arrangement is shown in the FIG. 3 embodiment, as described below. 
     In FIG. 3, a side view in elevation of another embodiment of the present invention is shown where, as in the above embodiment, the post  12 ′ is rotatably supported on a platform base  14 ′ and includes a pin  18 ′ that supports the pivot arm  16 ′. The pivot arm  16 ′ differs from the arrangement of the previous embodiment in that the end  28 ′ is enlarged to more readily accommodate a linkage array comprising link arms  32 ,  36  and  39  and the pivot joints  34 ,  38  and  40 . A wind speed detector  42  of conventional construction is provided on the end of arm  16 ′ and includes a link to arm  32  to shift arm  32  to the right as viewed in FIG. 3 when low wind velocities are detected and to the left when high wind velocities are detected. Thus, in a light wind, more vane area will be exposed to increase the lift while at a high wind speed, less vane will be exposed to reduce the lift and thereby the stress placed on the vanes and pivot arm  16 ′. The detector  42  may be a mechanical device as well as an electronic one as both types will be capable of shifting the arm  32  to effect the angular position of the vanes  22  and  23 . The opposite end of the pivot arm  16 ′ is provided with a pivot rod or pin  24 ′ on which are mounted two vanes only one of which,  23 , is shown in FIG.  3 . It will be understood that the vanes arrangement will be the same as that shown in FIGS. 1 and 2. 
     The link arm  32  is mounted in a suitable manner on the pivot arm  16 ′ and terminates in a joint  46  which is also located between the vanes  22  and  23  and includes link arm  30  which also extends between the vanes  22  and  23  without interfering with the movement of the vanes. Each of the link arms  30  terminates in a rod,  42  in the upper position and  44  in the lower position. These rods extend into the path of the vanes and as shown in FIG. 3, rod  42  is abutting the upper side of the vane  23  and will also be abutting the same side of the vane  22  although this is not shown in FIG.  3 . This will prevent further rotation in a clockwise direction about the pivot axis  24 ′. With the assembly and vanes positioned as shown in FIG. 3, a net lifting force will be imparted to the assembly to lift the vanes and the pivot arm  16 ′ in a counter clockwise direction about the pivot pin  18 ′ as viewed in FIG.  3 . As the pivot arm  16 ′ moves about a neutral position, that is, one where the vanes  22  and  23  extend parallel to the wind direction, the weight of the pivot arm  16 ′ combined with the lift afforded by the wind current will tilt the vanes either upwardly or downwardly to cause movement of the pivot arm. As movement commences, the leading edges of the vanes  22  and  23  will move into the wind direction due to the balance of the vanes about the pivot axis  24  and  24 ′ in each embodiment. This movement will tend to shift the vanes  22  and  23  to expose the opposite side to the wind current so that the pivot arm  16  and  16 ′ will commence movement in the opposite direction. Thus, the combination of the eccentric mounting of the vanes about the pivot pins  24  and  24 ′ in each embodiment will cause the oscillating movement of the respective pivot arms  16  and  16 ′. Also, by restricting the angular movement of the vanes  22  and  23  about the pivot pins  24  and  24 ′, the magnitude of the pivot arc of the pivot arm  16  and  16 ′ will be restricted. To this end, the vane stops  42  and  44  may be employed in the FIG. 1 form as shown at  60  and  62  and also are preferably adjustable. For example, as shown in FIG. 5, the pivot angle of the vanes  22 ,  23  is restricted to correspond to a high speed wind condition, one vane being shown in its upper and lower pivot positions. As in the FIG. 3 form, by moving the stops  60 ,  62  away from the post  12  and toward the end  24  of the arm  16 , pivoting through a greater angle will be permitted to accommodate low wind speeds. 
     The oscillating movement of the pivot arms  16 ,  16 ′ through an arc designated α in FIG. 3 and 26 in FIG. 1 can be utilized in a number of ways to generate current. With reference to FIG. 4, one manner of utilizing this motion is illustrated where a crank arm  36  is connected to a crankshaft  40  to a coupling  52  and an electrical generator  54  of conventional construction. Bearing supports  50  would normally be employed to support the crankshaft  40  and a coupling sleeve  38  mounts the crankshaft  36  to the shaft  40 . The height of the portion  56  in the crankshaft  40  will define the stroke U of the apparatus. 
     A number of modifications to the disclosed apparatus will be apparent to those skilled in this technology and such modifications will be understood to constitute a part of the present invention.