Abstract:
In a wave powered electric generator system, multiple floatation devices are interconnected by torque arms arranged to convert pivotal movement of the torque arms due to up and down movement of the floatation devices, into one-way rotational movement of electric generator shafts, the torque arms being configured to permit expansion and contraction of their lengths when exposed to sudden, severe axial forces.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of the Provisional Patent Application No. 61/163,574 filed in Mar. 26, 2009 and entitled TWIN POWER WAVE ENERGY CONVERSION and is incorporated herein in its entirety. 
     
    
     FIELD OF INVENTION 
       [0002]    This invention relates to a renewable energy sources. In particular, it relates to devices extracting power from water waves, particularly ocean waves, and producing electric power. 
       BACKGROUND OF INVENTION 
       [0003]    Wave energy is one of the renewal energy resources that deserves attention. Blowing wind and pressure fluctuations below the sea surface are the main reasons for causing waves. This wave motion could be harnessed to generate usable, energy that is clean and green. 
       SUMMARY OF THE INVENTION 
       [0004]    According to the invention, there is provided a wave powered electric generator system, comprising at least three floatation devices arranged serially to each other to define outer floatation devices and at least one inner floatation device, a torque arm connected between each pair of adjacent floatation devices, wherein the at least one inner floatation device includes at least one rotatable shaft, each rotatable shaft being secured to one of the torque arms to convert pivotal motion of the torque arm to rotational movement of the shaft, a one-way transmission system that provides one way rotation of a generator shaft in response to pivotal motion of the torque arm in either direction, and an electrical generator connected to the generator shaft. 
         [0005]    The at least one inner floatation device includes at least one floatation member, e.g., a single floatation member with a first and a second rotatable shaft, the first and second rotatable shafts being secured to torque arms extending to the floatation member from opposite sides, or two floatation members connected to each other, each floatation member including a rotatable shaft secured to a torque arm. 
         [0006]    Each torque arm preferably includes two sections connected by an axial force buffer that allows the two sections to move axially relative to each other. The axial force buffer may comprise a housing in which adjacent ends of the two sections of the torque arm are spaced apart in the housing and connected to at least one spring for buffering the axial movement of the two sections relative to each other. 
         [0007]    The one-way transmission system may include at least one one-way clutch gear arranged to transmit rotary motion in one direction only, or may include a first one-way clutch gear arranged to transmit rotary motion only in a clockwise direction in response to a clockwise rotation imposed on said first one-way clutch gear and transmit no rotary motion in response to a counter-clockwise rotation imposed on said first one-way clutch gear, and a second one-way clutch gear arranged to transmit rotary motion in a counter-clockwise direction in response to a counter-clockwise rotation imposed on said second one-way clutch gear and transmit no rotary motion in response to a clockwise rotation imposed on said second one-way clutch gear. The first and second one-way clutch gears may be connected to the generator shaft through a gearing arrangement in which one of said first and second one-way clutch gears is connected to the generator shaft via one more gear than the other of said first and second one-way clutch gears, to ensure that the direction of rotation of the generator shaft is the same for the rotation provided by both of the clutch gears. 
         [0008]    The outer floatation devices may include shafts for pivotally connecting to torque arms extending between the outer floatation devices and the at least one inner floatation device. 
         [0009]    Each floatation device may comprise a first and a second housing secured next to each other to define inwardly facing surfaces and outwardly facing surfaces with the shafts extending between the inwardly facing surfaces of said first and second housings, the torque arms being secured to the shafts at locations between said housings. For example, the housings may have a cylindrical configuration and the first and second housings of each floatation device are arranged axially next to each other with brackets securing the first and second cylindrical housings to each other. 
         [0010]    For stability, the system may include stabilizer bars inter-connecting the floatation devices along their outwardly facing surfaces so as to be pivotable relative to at least the inner floatation devices. Preferably each stabilizer bar includes two sections connected by an axial force buffer that allows the two sections to move axially relative to each other. The axial force buffer may comprise a housing in which adjacent ends of the two sections of the stabilizer bars are spaced apart in the housing and connected to at least one spring for buffering the axial movement of the two sections relative to each other. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1A  is perspective view of a floating generator system, according to an embodiment of the present invention; 
           [0012]      FIG. 1B  is a side view of an outer portion of the system of  FIG. 1A ; 
           [0013]      FIG. 1C  is a side view of an inner portion of the system of  FIG. 1A ; 
           [0014]      FIG. 1D  is a cutaway view of the inner portion shown in  FIG. 1C ; 
           [0015]      FIG. 2  is a cutaway view of one embodiment of a cylinder forming part of the system of the invention; 
           [0016]      FIG. 3A  is a perspective view of an alternative embodiment of a system of the invention; 
           [0017]      FIG. 3B  is a cutaway view of inner portions of the alternative embodiment of  FIG. 3A ; 
           [0018]      FIGS. 4A  and B illustrate the movements of the torque arm of the system in response to the effects of the waves on the inner portions of the device of  FIG. 1A , and 
           [0019]      FIG. 5  illustrates a transmission system which converts the rotary motion of the driven axle of one embodiment of the invention into usable energy. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    The exemplary embodiments described herein are for illustrative purposes only. The present invention is not limited to the particular floating wave power electric generating device as shown and described. It is understood that various omissions, substitutions or equivalents are contemplated, depending on the circumstances or requirements, and these are intended to be covered by the invention described herein without departing from the spirit or scope of the claims of the present invention. 
         [0021]    The terms “first,” “second,” and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another, and the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. 
         [0022]    The device of the present invention uses the up and down motion of the wave (e.g. ocean wave) to capture energy from that motion and convert it into useful energy (e.g. electricity). 
         [0023]      FIG. 1A  illustrates an embodiment of a floating generator system  100  capable of generating energy. The system  100  comprises a plurality of floatation units. The floatation units are organized into two outer sets  10 , and at least one inner set  20  placed between these two outer sets  10 . In the embodiment of  FIG. 1  two inner sets  20  are included. As shown in  FIGS. 1B , C and D, each set, regardless of inner or outer, is formed by securely attaching one end of a floatation unit  12 ,  22  to another by a pair of brackets  50 . However, only the floatation units of the inner sets  20  contain within them the transmission system and the electric generator  90  connected thereto. Further differences between the inner and outer sets include the presence of an outer axle  11  in each of the outer sets  10  (as shown in  FIG. 1B ), and of two driven axles  60  in each of the inner sets (as shown in  FIGS. 1  C and D). In  FIGS. 1C  and D, each driven axle  60  can interact directly with the transmission system to convert the motion of the waves into usable energy. While the floatation units shown in this embodiment are cylindrical in configuration, it will be appreciated that other shapes could be used, e.g., spherical floatation units. 
         [0024]    In  FIG. 1A , on both sides of the floating system  100 , the side interconnectors or stabilizer bars  30  are configured to pivotally attach all sets together. It will be appreciated, however, that pivotal movement need only be provided between the stabilizer bars and the inner sets  20  On the other hand, as shown in  FIG. 1B , the torque arm  40  is configured to rigidly attach at its one end to a rotatable shaft that defines a driven axle  60  of the inner set  20 , and insofar as the other end of the torque arm  40  is connected to an outer set  10  of floatation units  12 , it is connected in this embodiment to a free-wheeling shaft rotatably mounted to the floatation units  12 . In another embodiment the shaft may be non-rotatably secured to the floatation units  12  and the torque arm can be rotatably mounted relative to such non-rotatable shaft. Insofar as the other end of the torque arm is connected to another inner set  20  of floatation units  22 , it is securely attached to a rotatable shaft that defines the driven axle  60  of said other inner set  20 . As illustrated by  FIG. 1D , for any inner set  20 , the torque arm  40  coming in from the left is configured to securely attach to the driven axle  60  on the left and the torque arm  40  coming out from the right is configured to securely attach to a driven axle  60  on the right. Thus, up and down pivoting of the torque arms will produce rotary motion in the driven axle  60  as will become clearer from the discussion below. 
         [0025]    As illustrated in  FIGS. 1A-D , between each set of adjacent side interconnectors  30  and torque arms  40 , there is an axial force buffer in the form of a cylinder  15  that allows the lengths of the torque arms  40  and interconnectors  30  to change when an axial force is exerted on them. By being able to expand and contract the length between adjacent side interconnectors  30  and torque arms  40  automatically, the cylinder  15  insures the integrity and the survival of the floating system  100  during storm or bad weather which can cause rough waves, and allows for the maximum production of usable energy by being usable in any weather conditions.  FIG. 2  illustrates the inner working of the cylinder  15 . Within cylinder  15 , side interconnector  30  or torque arm  40  does not extend straight through, but two separate rods are defined by the interconnectors or torque arms extending into the cylinder from opposite ends with a gap between the rods. A spring  33  is placed over each rod. For each rod a spring stopper  35  attaches to the end of the rod and prevents the spring  33  from sliding off the rod allowing the rod to slide freely back and forth and turn in cylinder  15 . A cap  34  mounts at each end of the cylinder  15  to keep the spring  33  and the rod inside the cylinder. Whenever the waves cause the adjacent side interconnectors  30  or torque arms  40  to be pulled in different directions abruptly or violently, the rods in cylinder  15  can compress the springs  33  allowing the overall distance between the outer ends of the interconnectors  30  or torque arms  40  to increase, thereby accommodating the sudden changes. As soon as there is no more force pulling on the rods, the springs  33  snap back and retract the rods to their former positions in the cylinder. Typically the springs are chosen with a compressive force capability that takes account of the severity of the wave conditions in which the system is to be used. While the above embodiment had the axial force buffer mounted between two sections of the torque arms  40  and between two sections of the interconnectors  30 , it will be appreciated that the torque arms and interconnectors could instead be defined by a single elongate member with a force buffer mounted at one of the ends. Also, since the purpose of the axial force buffer is to accommodate axial forces acting on the torque arms and interconnectors during rough sea conditions, any arrangement that allows the length of these members to change (either contract or extend) would work and need not require a pair of springs. A piston arrangement could be used instead or a single spring connected between the torque arm or interconnector sections or connected between one end of the torque arm or interconnector and the shaft to which it is connected could be used in other embodiments. 
         [0026]      FIGS. 3A  and B show another embodiment of this invention, in which two inner sets are attached to each other ( 20   a ). As such there is no torque arm  40  between them. In this embodiment, because there is only one driven axle  60  attached to each inner set, each floatation unit of the inner set can only carry a maximum of one transmission system and one electric generator  90  within it. In contrast, in the embodiment as shown in  FIGS. 1A-D , because there are two driven axles  60  attached to each inner set, each floatation unit of the inner set can carry two transmission systems and two electric generators within it. It is desirable to distribute the weight of the floating system  100  evenly so that it is more stable floating on water. For example, if one were to use the embodiment as shown in  FIGS. 3A  and B the two electric generators should preferably be placed in the two floatation units of the inner sets located diagonally to each other in order to create a balanced distribution of weight. 
         [0027]      FIGS. 4A  and B show the movements of the torque arm  40  and the driven axle  60  in response to the effects of the waves on the inner sets  20 . If the wave causes the inner set  20  to be swung down to the valley of the wave (wave trough), the driven axle  60  on its left will rotate clockwise, while the driven axle  60  on its right will rotate counterclockwise. On the other hand, if the wave causes the inner set  20  to be swung up to the top of the wave (wave crest), the driven axle  60  on its left will rotate counterclockwise, while the driven axle  60  on its right will rotate clockwise. Each rotation, whether clockwise or counterclockwise, will engage the transmission system and in turn, will produce electricity through the electric generator  90 . 
         [0028]    The one-way transmission system is shown in detail in  FIG. 5 . A primary gear  72  is mounted on one end of the driven axle  60  and configured to integrally rotate with it. The double gear  73  contains a small gear affixed to a big gear. The primary gear  72  is capable of meshing with the small gear in such a way that when the primary gear  72  is rotated, it, in turn, rotates the small gear of the double gear  73 . The small gear will transmit the rotary motion it receives into a higher speed rotation through the rotation of the big gear of the double gear  73 . The direction of the rotation of the big gear of the double gear  73  will dictate what other gears in the transmission system will rotate in turn. For example, when the big gear of the double gear  73  rotates clockwise, it will only engage the first one-way clutch gear  77  on shaft  75  and thus, shaft  75  will rotate counter-clockwise. The rotation of shaft  75  causes the first large gear  79  mounted on shaft  75  to rotate. The first large gear  79  on shaft  75  is capable of meshing with the second large gear  78  on shaft  74  to transmit the rotary motion in such a manner that the rotation of shaft  75  is always opposite to the rotation of shaft  74 . The rotation of the second large gear  78  on shaft  74  is therefore clockwise and, in turn, rotates the torque limiting clutch gear  81  located on the flywheel shaft  80  in a counter-clockwise direction. The torque limiting clutch gear  81  interacts with the flywheel shaft  80  in such a way that when the torque on the torque limiting clutch gear  81  reaches a certain limit, the torque limiting clutch gear  81  slips or disengages the flywheel shaft  80  to prevent it from over-rotating and thereby cause damage to the electric generator  90 . Also, mounted on the flywheel shaft  80  is the flywheel  82  designed to improve energy production, and the driving mechanism  83  for transmitting the rotary motion of the flywheel shaft to the electric generator  90 . When the flywheel shaft  80  rotates, the driving mechanism  83  will engage the electric generator  90  and produce electricity. 
         [0029]    On the other hand, if the big gear of the double gear  73  rotates counterclockwise, it will only engage the second one-way clutch gear  76  on shaft  74 , and thus shaft  74  will rotate clockwise. The rotation of shaft  74  will cause the rotation of the second large gear  78  in a clockwise direction, and thus again produce counter-clockwise rotation of the torque limiting clutch gear  81 , the flywheel shaft  80 , the flywheel  82 , and the driving mechanism  83 , and produce electricity through the electric generator  90 . 
         [0030]    While the invention was discussed with reference to two specific examples, as mentioned above, the invention is not so limited and includes other embodiments as defined by the claims without departing from the scope of the invention.