Abstract:
An energy conversion system includes a first mechanical system for converting reciprocating motion to rotary motion, a second system formed of belts and pulleys connected to said first system and driven by said rotary motion to lift a weight in response to said rotary motion from a first position to a second position and allow the weight to return to said first position under the influence of gravity. A rotary electrical is driven by the second system through a transmission means connected to the second system to create electricity only while the weight is returning from its second to its first position.

Description:
BACKGROUND OF THE INVENTION 
     This application is based on and claims the benefit of Provisional Application No. 60/874,956 filed Dec. 15, 2006 and is a divisional of U.S. patent application Ser. No. 11/955,469 filed Dec. 13, 2007, the disclosures of each of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the development of electrical power from mechanical energy produced from waves or other sources of motion. 
     The conversion of mechanical energy into electrical power is of great interest today given the costs of petrochemical fuels and the recent dramatic increase in energy demands by developing nations. One particular source of such alternative energy which has attracted substantial interest is the conversion of ocean wave energy into electrical power. 
     Many different forms of wave energy conversion devices have been proposed, which involve direct conversion of vertical wave motion to electrical energy using turbines, mechanical connections and even metal coil windings as disclosed for example in U.S. Pat. Nos. 4,389,843; 4,914,915; 6,857,266; 3,546,473; and 6,864,592. 
     Most of the prior art wave conversion devices are designed to require persistent high amplitude wave energy. However it is difficult to find areas in which there is a prevalence of high ocean wave activity with sufficient energy to allow most such devices to operate efficiently. And, such areas often are located in the remotest portions of the oceans. 
     Other of such systems use direct coupled generators that suffer reduced efficiencies due to speed variations at the generator during wave cycles. Still others operate at subsurface levels using the head differential of waves to generate power or complex pumping or pressurization of secondary fluids to turn generators. 
     Accordingly there has been a long need for a system that can be effective through a wide range of energy conditions, including those for which existing systems are inefficient. 
     OBJECTS OF THE INVENTION 
     It is an object of the invention to convert energy from moving water, i.e., wave energy and energy from water surges to electrical energy through direct mechanical conversion. 
     Another object of the invention is to convert wave energy to electrical energy through a mechanical conversion system which applies constant torque and shaft speed to an electrical generator during the power stroke. 
     Another object of the invention is to reduce power losses in the conversion of wave energy to electrical energy by first converting wave energy to potential energy and then recovering that energy by mechanically driving a generator at a constant speed. 
     Yet another object of the invention is to extract energy from sea waves at the water surface where the energy density is the greatest. 
     A further object of the present invention is to utilize a mechanically simple device to convert wave action into electrical energy without the use of linear generators or complex control systems. 
     A still further object of the present invention is to convert wave energy into electrical energy using a mechanical conversion system which is simple and inexpensive to manufacture, assemble and maintain. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the present invention a device for converting wave energy to electrical energy includes a first vertically arrayed continuous belt or chain moving about upper and lower pulleys or sprockets and having one or more heavy weights secured thereto. One of the pulleys or sprockets is driven in one predetermined direction by a second belt or chain which is engaged with a series of one way gear sprockets or pulleys that are moved relative to the second belt by a mechanical linkage arranged to reciprocate in response to wave motions. 
     The first belt or chain is also engaged through a transmission system to an electrical generator so that movement of the first belt drives the generator. By this arrangement when the weights on the first belt are moving downwardly under the influence of gravity the falling weights deliver a constant torque and speed at constant load to the generator. 
     The one way gears or pulleys connected to the second chain consist of at least one pair of oppositely acting one way sprockets each being engaged with different sides of the belt or chain and arranged to drive the belt in the same direction. These sprockets are mounted on a carriage which can be moved relative to the second belt by a mechanical arm connected at one end to the carriage and at its other to a float on the surface of the body of water on which the system is deployed. 
     By this arrangement one of the one way gear sprockets engages the chain belt to drive it when the sprocket carriage is moved upwardly and the other one way gear sprocket will move the second chain belt in the same direction when the carriage is moved downwardly. In this way the first chain belt carrying the weights is always driven in the same direction, regardless of the direction of motion of the carriage. The gearing of these one way sprockets is such that the chain belt is moved even in low wave or water surge heights which produce only limited vertical travel or amplitude of movement of the carriage. 
     The above and other features, objects and advantages of the present invention will be apparent to those skilled in the art from the following detailed description of the illustrative embodiments thereof when read in connection with the accompanying drawing wherein: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an elevational view of a Marine Wave Energy Conversion System constructed in accordance with the present invention; 
         FIG. 2  is a side sectional view of the device shown in  FIG. 1 , taken along lines  2 - 2  of  FIG. 1 , with the internal mechanism shown schematically; 
         FIG. 3  is a sectional view taken along line  3 - 3  of  FIG. 2 , again with the internal mechanism shown schematically; 
         FIG. 4  is an enlarged schematic view of a portion of the energy conversion system shown in  FIG. 2 ; 
         FIG. 5  is an enlarged perspective view of mechanical conversion system and power take off mechanism shown in  FIG. 5 ; 
         FIG. 6  is a further enlarged perspective and more detailed view of a portion of the power take off mechanism shown in  FIG. 5 ; 
         FIG. 7  is a front perspective view of the apparatus of  FIG. 1  showing one embodiment of the float arrangement; 
         FIG. 8  is a top view taken along line  8 - 8  of  FIG. 1 ; 
         FIG. 9  is a perspective view of a preferred form of drive belt used in the system shown in  FIGS. 1-8 ; and 
         FIG. 10  is a view similar to  FIG. 2  of another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings in detail, and initially to  FIGS. 1 and 2  a marine wave conversion system  10  is illustrated which is adapted to convert ocean wave energy to electrical power. However, the conversion mechanism itself can be used with sources of power or movement other than ocean waves for the same purpose of converting motion to electrical power. 
     In the illustrative embodiment the system  10  includes a pair of submersible towers  12  which enter into and support an upper housing  14 . The towers  12  are of substantially identical construction, being hollow members, connected at their bottoms  16  to a base  18  which may include a plurality of ballast chambers (not shown). 
     The system  10  is illustrated in place in a body of water, like an ocean or large lake. It is secured to the sea bed  19  by anchors  22  and cables  24  in any convenient or known manner so that, with the appropriate ballast the tower  12  and the housing  14  mounted thereon can heave and pitch relative to the surface float  26  described hereinafter. By proper tuning using ballast and the like as would be apparent to those skilled in the art, the tower and housing assembly can have a different frequency in the wave spectrum as compared to float  26  to provide an increased response over a broader frequency band. 
     Although the illustrative embodiment utilizes two towers and their associated internal conversion systems described below, it is to be understood that the invention contemplates the use of either one tower or more than two towers as well. 
     The system  10  includes a water surface float  26  connected to a pair of pivot arms  28  (see  FIG. 7 ) pivotally mounted on housing  14  as described hereinafter. Wave motion causes the float  26  to rise and fall on the waves relative to housing  14  and towers  12 . (Cf. the water lines  30  of  FIGS. 1 and 2 , which causes the arms  28  to pivot on housing  14 .) An inner arm or extension  32  of arm  28  shown schematically in  FIG. 3  is therefore also caused to pivot on the housing, moving its free end  34  up and down with the passage of the waves. 
     The inner end  34  of arm  32  is connected as described hereinafter to a transmission system  36  which converts the up and down movement of arm  32  to rotary motion to drive an electric generator for the production of electricity. 
     Transmission system  36  is shown in greater detail in  FIGS. 5 and 6 . The systems in each tower  12  are identical so only one is described. As shown in  FIG. 2  the two systems  36  are illustrated in mirror image positions, but they could be positioned in the same relative positions if desired. 
     Transmission system  36  consists of two main subsystems. The first is a carriage system and clutch assembly  38  for converting the reciprocal movement of arms  32  to linear movement of a drive belt. The second is a generator drive transmission  40 . Both the carriage assembly  38  and transmission  40  utilize chain and sprocket or belt and pulley systems drives as desired. While the systems shown in the drawings are belts and pulleys they could be chains and sprockets. Accordingly applicant refers herein to these elements as belt/chain, pulley/sprocket, belt or chain, pulley or sprocket interchangeably. 
     Generator drive system  40  is driven by the carriage system  38  as described hereinafter to drive the input shaft  42  of a rotary electric power generator  44 . The system includes a central support tube  46  which is supported within its associated tower  12  by a plurality of flanges  48  which extend radially outwardly. The outer ends of these flanges are secured, by welding or the like, to the inner surface of the tower  12 . Other structures for supporting the weights and carriage can also be used. 
     A pair of pulleys/sprockets  50  are supported at the upper end  52  of tube  46  on a shaft  54  mounted in bearing blocks  56 . Those bearing blocks are mounted in the tower  12  in any conventional manner as would be apparent to one skilled in the art. 
     A lower pair of pulleys/sprockets  58  are mounted for rotation on the lower end  60  of tube  46 , again in any convenient manner, below and in vertical alignment with pulley/sprockets  50 . A pair of belts/chains  62  are engaged over the pairs of aligned pulleys/sprocket  50 ,  58 , as shown. These belts support one or more relatively heavy weights  64 . These weights are shown in the illustrative embodiment as cylindrical members having end shafts  66  mounted in bearing blocks  68  secured in any convenient manner to the belts  62 . For example in the case where the belt/chain is a belt, the bearing blocks may be secured to a flexible strip  67  secured to the belt by appropriate adhesives, stitchings or the like. 
     As described hereinafter the reciprocation of carriage  38  drives the belts/chains  62  of transmission  40  in the counterclockwise direction as shown in  FIGS. 5 and 6 , lifting the weights to and over the top of tube  46 , at that point the weights  64  drive the belts  62  as they “fall” downwardly under the influence of gravity. This motion is transmitted through a subtransmission  65  to drive generator  44 . 
     In a preferred embodiment the various belts used in the system of the present invention are so-called duplex belts as shown in  FIG. 9  which have molded teeth on both sides for mating with corresponding teeth on their associated pulleys. 
     Carriage system and clutch assembly  38  consists of a frame  74  rigidly connected to a yoke or other means of suspension  76  whose upper end is connected to the end  34  of arm extension  32 . Frame  74  has sides  77  on which a plurality of guide rollers  78  are mounted in pairs at 90° to each other. These guide rollers engage right angle guide tracks  80  (See  FIG. 8 ) mounted on the walls of the upper housing  14 , so that as the carriage reciprocates in the vertical direction in response to wave action it is guided in a fixed vertical plane in order to ensure that the various belt/pulley contact points described below remain in alignment. This structure also is simply illustrative of a particular embodiment for guiding the carriage. 
     In the illustrative embodiment of the invention three pairs of pulley/sprockets  82  that include one way clutches, e.g., sprag clutches, are mounted on carriage  74  so that the pulley/sprockets can engage and drive an associated belt  84  in one direction and free wheel in the opposite direction. As shown by the arrows in  FIG. 4 , the upper and lower pairs of one way pulley/sprockets  82  are set to drive the belt  84  when they rotate in the clockwise direction and free wheel when they rotate in the counter clockwise direction. The middle pair of one way pulleys/sprockets are set to drive belt/chain  84  when they rotate counterclockwise and free wheel when they rotate clockwise. 
     Belt  84  is trained through one way pulleys/sprockets  82  on frame  74  as shown and also engages upper and lower pulley/sprockets  86 ,  87 . Sprocket  86  is mounted for rotation on a shaft  88  which is supported on bearing blocks  90  mounted in a fixed position in housing  14  in any convenient manner above pulley/sprockets  82 . Lower sprocket  87  is similarly rotatably mounted on a shaft  54  supported in one of the bearing blocks  56 . Sprocket  87  is fixed to an overrunning clutch  87 ′ secured to shaft  54  so that movement of belt  84  will drive sprocket  87  and clutch  87 ′. The latter is connected to a pulley/sprocket  89  which is fixed to the adjacent pulley sprocket  50 . As a result reciprocal movement of carriage  74  relative to belt  84  will cause the belt always to be driven in a counterclockwise direction, thereby driving pulley/sprockets  50  and belts  62  until the weights  62  pass over the top of pulleys/sprockets  50  at which point the overrunning clutch releases under the force of the weights so the clutch free wheels and the weights can “fall,” continuing to drive belts  62  until they reach the bottom pulley  58  and clutch  87 ′ reengages. 
     As will be apparent from  FIG. 4  when carriage  74  is moved upwardly as a result of downward movement of float  26  belt  84  will move in the direction of arrow A since the middle pair of one way pulley/sprockets are engaged thereby driving the belt in the direction while the upper and lower pairs of one way pulley/sprockets free wheel. 
     Conversely when carriage  74  moves downwardly as a result of upward movement of float  26  the upper and lower pair of sprockets  82  as seen in  FIG. 4  engage to continue to drive belt  84  in the same direction, while the middle pair of pulley sprockets freewheel. As a result pulley/sprocket  87  is continuously driven to rotate pulley/sprockets  50 . 
     Preferably the belt  84  can be a called “duplex” belt  55  as seen in  FIG. 9  having teeth molded therein on both sides to engage corresponding teeth on the sprockets/pulleys  82 . 
     A third belt/chain  92  drivingly connects system  40  to transmission system  65 . Belt/chain  92  is trained about the pulley/sprocket  89  secured to the adjacent pulley/sprocket  50  for rotation therewith. The belt  92  is also trained over a pulley/sprocket  94  mounted on a shaft  96  supported in bearing blocks  98 . A second larger pulley/sprocket  100  is also secured to shaft  96  to drive a belt/chain  102  which is trained over a smaller pulley/sprocket  104  fixed to a shaft  106  supported in bearing blocks  108 . 
     Shaft  106  is connected to a large pulley/sprocket  112  and a belt/chain  114  is trained over pulley/sprocket  112  and a drive pulley/sprocket  116 . The belts/chains  102 ,  114  have tensioning rollers or sprockets  115  associated with them and mounted in housing  14  in any convenient manner. A centrifugal clutch  110  is engaged between sprocket  116  and generator  44  on generator shaft  42 . The clutch is preferably located in the position where the highest shaft speeds are developed but could be located elsewhere in the drive train. 
     As a result of this construction when the weights  62  begin to free fall after passing over the tops of pulleys  50  the overrun clutch  87 ′ disengages and the centrifugal clutch  110  engages once a predetermined shaft speed is achieved in pulley  116 . At that point transmission  65  acts as a step up transmission driving the shaft of generator  44  at the desired efficient speed to produce electricity which is transmitted to a grid or storage facility through power lines (not shown). 
     While the weights are falling movement of carriage  74  has no effect on the belts/chains  62  because of the overrunning clutch  87 ′. Electricity therefore is produced only on descent of the weights. While the weights fall solely under the influence of gravity (thereby using the potential energy stored in them from the wave activity which raised them) they fall at a constant speed related to the torque and shaft speed required by the generator. The amount of torque developed by the weights is a function of the various pulley/sprocket diameters, step up rates of the transmission and the generator&#39;s requirements. 
       FIG. 7  shows one embodiment for connecting the float to the pivot arms  28  and yokes  76 . In the illustrative embodiment a pair of arms  28  is provided which are pivotally mounted on pins  120  supported between pairs of flanges  122  on housing  14 . The arms  28  have extensions  32  as noted above which extend between flanges  122  in each pair and are pivotally connected to the top of yoke  76 . Yoke  76  may be pivotally connected to carriage  74  so that its two pivotal connections accommodate the arcuate movement of extension  32  while the carriage is restrained to vertical movement. Alternatively other flexible connections known in the art to accommodate such movements may be used. 
     As seen in  FIG. 7  the float  26  can be connected to arms  28  at various points to adjust the amount of movement of the arm created by wave action. In the illustrated embodiment three sets of pivot holes  130  are provided in each arm, only two of which are seen in the drawing. The third set in this case is located within float  26  to pivotally connect the arms to the float in the intermediate of the three positions. 
     It is a significant characteristic of the disclosed embodiment of the invention that only relatively small vertical motion of the frame or carriage  74  is necessary to cause motion in belts/chains  62 ; thus wave motion or water surges sufficient to cause the pulley/chain to move by only one tooth on the one way or sprag clutches will be enough to cause the chains  62  to move to lift weights  64  and store potential energy. This characteristic is particularly important in circumstances in which there is wide variation in amplitude of the motion of the lever arm  28 . However, significant power generation occurs when the weights  64  fall and release their potential energy to drive belt/chains  62  and operate the generator. 
     It must be noted that the illustrations of the invention herein are not to scale and that, for example, the height to width of the carriage  74  would be much greater than represented in the drawing in order to maximize the length of vertical travel of the one way pulley/sprockets  82 . 
       FIG. 10  illustrates another embodiment of the invention wherein the carriage assemblies associated with towers  12 ′ are enclosed within separate housing  14 ′. A single float  26 ′ is provided between towers  12 ′ and connected to arms  28 ′ which are fixed to a shaft  130 . That shaft is rotatably mounted in bearings  132  in the respective housings  14 ′ and has extension arms (not shown) fixed to it and secured to yokes  78 ′ to reciprocate carriage assembly  38 . 
     In addition, in this embodiment, instead of using the additional pulley/sprocket  90  and belt  92 , the belt/chains  62  are shown to be extended to engage the pulley/sprocket  94  and drive it directly. Of course where two belt chains  62  are used as in the embodiment of  FIG. 6 , they would be two pulley/sprockets  94 , one for each belt/chain  62  mounted on shaft  96  to drive pulley/sprocket  100 . 
     In addition, using the arrangement shown in  FIG. 10 , more than one energy conversion system  36  can be located on each tower  12 ′ and housing  14 ′. 
     While the above described embodiment is particularly adapted to the use of ocean waves to drive the carriage  74 , those skilled in the art would appreciate that the system could be readily adapted to other sources of power input. One such example would be a windmill used to drive a cranking mechanism to raise and lower the carriage assembly, or even a manually operated cranking assembly for emergency power. 
     Although the invention has been described herein with reference to the specific embodiments shown in the drawings it is to be understood that the invention is not limited to such embodiments and that various changes and modifications may be effected therein without departing from the scope or spirit of the invention.