PATENT ABSTRACT
A buoyant kinetic energy apparatus, used for solving the problem that the kinetic energy generation efficiency of an existing buoyant kinetic energy apparatus is low, comprises: a base ( 1 ), provided with a liquid tank ( 11 ); a rotor ( 2 ), provided with a rotary body ( 21 ) and a shaft part ( 22 ), the shaft part ( 22 ) combining the rotary body ( 21 ) and the liquid tank ( 11 ), and the rotary body ( 21 ) being rotatably arranged in the liquid tank ( 11 ) by means of the shaft part ( 22 ); a float ( 3 ), telescopically arranged on the rotary body ( 21 ); and a telescoping control module ( 4 ), arranged in the liquid tank ( 11 ) and controlling the float ( 3 ) to telescope relative to the rotary body ( 21 ) when the rotary body ( 21 ) rotates.

PATENT DESCRIPTION
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an apparatus for generating kinetic energy and, more particularly, to a buoyancy-driven kinetic energy generating apparatus and method for generating kinetic energy by using the buoyancy-driven kinetic energy generating apparatus. 
         [0003]    2. Description of the Related Art 
         [0004]    In the developing history of human civilization, many kinetic energy generating apparatuses capable of generating kinetic energy have been proposed to drive a device or to covert the kinetic energy into electric energy for wider applications, improving the life quality of human. These kinetic energy generating apparatuses are generally of two types: one of them uses natural energy as the power for generating kinetic energy, such as wind power generation, solar power generation, hydro-power generation, etc., and the other consumes natural resources to generate the power for generating kinetic energy, such as nuclear power generation, coal-fired power generation, etc. However, these kinetic energy generating apparatuses still have disadvantages. 
         [0005]    Firstly, although the kinetic energy generating apparatuses using natural energy is cheap, abundant, and pollutionless, the occurrences of the natural energy and its intensity can not be controlled such that maintaining a stable energy generating efficiency of the kinetic energy generating apparatuses using natural energy is difficult. 
         [0006]    Secondly, although the kinetic energy generating apparatuses consuming natural resources can easily be controlled, the natural resources are not exhaustless. The natural resources will exhaust someday under large-scale mining by the human. Furthermore, operation of the kinetic energy generating apparatuses consuming natural resources not only have safety risks but generates waste (such as nuclear waste) causing severe environmental pollution. Treatment of the waste further incurs tricky and costly problems. 
         [0007]    To solve the above problems, a buoyancy-driven kinetic energy generating device utilizing buoyancy has been developed. With reference to  FIG. 1 , a conventional buoyancy-driven kinetic energy generating device  9  includes a tower  91  receiving a conveyor  92 . The conveyor  92  is connected to and drives a rotary shaft  93  to rotate. The rotary shaft  93  is connected to a generator  94  outside of the tower  91 . A plurality of buckets  921  is mounted to the conveyor  92 . An opening of each bucket  921  faces downward when it is adjacent to a bottom of the tower  91 . A bubble supply means  95  fills gas bubbles into the bucket  921  reaching a lower portion of a side of the conveyor  92  to generate buoyancy. When the bucket  921  with bubbles moves upward to a position above the water surface, the gas in the bucket  921  is discharged, and the bucket  921  sinks into the water with the opening of the bucket  921  facing upward to receive water for smooth sinking. An example of such a buoyancy-driven kinetic energy generating device is disclosed in U.S. Pat. No. 7,216,483 entitled “POWER GENERATING SYSTEM UTILIZING BUOYANCY”. 
         [0008]    However, operation of the buoyancy-driven kinetic energy generating device  9  requires additional power to actuate the bubble supply means  95  for generating bubbles and filling the bubbles into the buckets  921  so as to continuously drive the conveyor  92  by buoyancy to thereby drive the generator  94  to generate electric energy. Furthermore, since the buoyancy-driven kinetic energy generating device can only use the buoyancy of less than half of the buckets  921  to drive the conveyor  92  while each bucket  921  has a limited capacity, it is difficult to increase the total buoyancy, resulting in inefficient operation of the conveyor  92 . 
         [0009]    Furthermore, the buoyancy-driven kinetic energy generating device  9  has many components leading to high costs in manufacture, assembly, and maintenance. During operation, the conveyor  92  and the rotary shaft  93  are connected by a chain and gears moving in the water. These mechanical components have high friction therebetween and, thus, can not move smoothly without sufficient lubrication. Operation in the water causes difficult lubrication and increases the resistance to meshing. All of these increase the resistance during operation of the buoyancy-driven kinetic energy generating device  9 . Furthermore, when each bucket  921  is moved above the water surface and is about to sink into water again, a resistance occurs during sinking of the bucket  921 . Furthermore, after each bucket  921  is in the water, the residual air in the bucket  921  generates buoyancy while the water is filling the bucket  921 , causing further resistance to operation of the conveyor  92 . In view of these factors, the buoyancy-driven kinetic energy generating device  9  not only consumes energy but must use a high-resistance mechanical structure with a resistance not larger than the total buoyancy. Thus, the buoyancy-driven kinetic energy generating  9  is in inefficient in generating kinetic energy. 
         [0010]    In view of the above reasons, an improvement to the conventional buoyancy-driven kinetic energy generating device is necessary. 
         [0011]    Besides, U.S. Pat. No. 4,363,212 discloses a buoyancy prime mover, U.S. Pat. No. 4,363,212 discloses a buoyancy prime mover with pressure control means, and U.S. Pat. No. 6,305,165 discloses methods and apparatus for acquiring free energy using buoyancy technology. Taiwan (province of China) Patent Publication No. 200408766 discloses a buoyancy kinetic energy machine. Taiwan Patent Publication No. 200632212 discloses hydraulic power generation apparatus using alternating gravity and buoyancy forces. Taiwan Patent Publication No. 200714801 discloses a generator of constant power energy. Taiwan Patent Publication No. 201217638 discloses a buoyancy power generator, and a buoy device and a transmission device of the buoyancy power generator. Taiwan Patent Publication No. 201319385 discloses a simple underwater power generation device. China Patent Publication No. 1508423 discloses a buoyancy kinetic energy machine. China Patent Publication No. 101201040 discloses a circulating gas-bag buoyancy power arrangement, China Patent No. 102112740 discloses a power generation, apparatus. China Patent No. 102374108 discloses a buoyancy and gravity circulating electricity generation method. China Patent No. 102852706 discloses a buoyancy power machine. China Patent No. 103291533 discloses a buoyancy engine. China Patent No. 103511174 discloses an earth gravity and liquid buoyancy power generation device. China Patent No. 103511209 discloses a density difference engine. Japan Patent Publication Nos. 56-113066, 2007-132214 and 2013-113293 also disclose similar buoyancy-driven kinetic energy generating devices. The above buoyancy-driven apparatuses also use buoyancy force to generate kinetic power. However, these buoyancy-driven apparatuses have disadvantages such as complex structure and low kinetic energy generation efficiency. 
         [0012]    In light of this, it is necessary to improve the conventional buoyancy-driven apparatuses. 
       SUMMARY OF THE INVENTION 
       [0013]    An objective of the present invention is to provide a buoyancy-driven kinetic energy generating apparatus having increased total buoyancy while having a lower resistance during operation, allowing smooth operation of the buoyancy-driven kinetic energy generating apparatus to enhance the kinetic energy generating efficiency. 
         [0014]    Another objective of the present invention is to provide a buoyancy-driven kinetic energy generating apparatus having a simple structure to reduce the costs of manufacture, assembly, and maintenance. 
         [0015]    To achieve the above objectives, the invention utilizes the following techniques. 
         [0016]    A buoyancy-driven kinetic energy generating apparatus includes a base including a tank, a rotor, at least one float and a telescopic movement control module. The rotor includes a rotor body and a shaft portion. The shaft portion is coupled to the rotor body and the tank. The rotor body is rotatably received in the tank about a rotating axis defined by the shaft portion. The at least one float is telescopically mounted to the rotor body. The telescopic movement control module is mounted in the tank and controls the at least one float to telescope relative to the rotor body while the rotor body rotates. 
         [0017]    The tank is adapted to receive a liquid. The rotor body has an interior. The interior of the rotor body is hollow and adapted to receive a mass having a density smaller than a density of the liquid to create buoyancy to float the rotor body on the liquid in the tank. Alternatively, the rotor body has a density smaller than a density of the liquid to create buoyancy to float the rotor body on the liquid in the tank. 
         [0018]    The shaft portion of the rotor body may be connected to a speed regulating device. 
         [0019]    The at least one float is telescopically mounted to an outer surface of the rotor body. Furthermore, the outer surface of the rotor body includes first and second end faces and a peripheral face connected between the first and second end faces. The first and second end faces oppose to each other. The at least one float telescopically is mounted to the peripheral face of the rotor body and telescopically moving in a radial direction relative to the rotor body. 
         [0020]    The base includes two shaft fixing portions. The two shaft fixing portions are respectively mounted to two opposite outer sides of the tank respectively of two lateral walls of the tank and coaxial to each other. The shaft portion of the rotor body includes two shafts. Each of the two shafts includes a shaft hole. Each of the two shafts includes an end mounted to a respective one of the first and second end faces of the rotor body, as well as another end extending through the tank and connected to a respective one of the two shaft fixing portions. The shaft holes of the two shafts intercommunicate an interior of the rotor body with an outside of the tank. 
         [0021]    The telescopic movement control module may include a guiding track and at least one slidewheel unit. The at least one slidewheel unit has a same quantity as the at least one float. Each of the at least one slidewheel unit is mounted to the rotor body and connected to a respective one of the at least one float. The guiding track is mounted in the tank and guides the at least one slidewheel unit to move, thereby controlling the telescopic movement of the respective one of the at least one float. 
         [0022]    The guiding track includes an abutment face facing the peripheral face of the rotor body. 
         [0023]    The guiding track includes a movement control section and a maintaining section arranged in sequence in a rotating direction of the rotor. The movement control section and the maintaining section are connected to each other. A spacing between the movement control section and a rotating center of the rotor decreases from a point of the movement control section toward the maintaining section. The abutment face and the peripheral face of the rotor body are concentric in the maintaining section. 
         [0024]    A telescopic movement end line is at an angle of 45° to a horizontal line. The telescopic movement end line passes through a rotating center of the rotor body and the maintaining section of the guiding track. The telescopic movement end line passes through a location at an upper portion of the rotor body. The location defines a maximal level. The horizontal line passes through the rotating center of the rotor body and defines a minimal level. A level of the liquid is between the maximal level and the minimal level. 
         [0025]    The at least one float includes a first float. The peripheral face of the rotor body includes a first slot. The first float includes a housing and an isolating member. The housing has an open end and is received in the first slot. The open end faces the interior of the rotor body. The isolating member connects the housing of the first float to the rotor body. The isolating member seals the first slot. 
         [0026]    Alternatively, the at least one float may further include a second float opposite to the first float in a diametric direction of the rotor body. The peripheral face of the rotor body further includes a second slot. The second float includes a housing. The housing of the second float has an open end and is received in the second slot. The open end of the housing of the second float faces the interior of the rotor body. The second float further includes an isolating member connecting the housing of the second float to the rotor body. The isolating member of the second float seals the second slot. 
         [0027]    A connecting module may be connected between the first and second floats. The connecting module includes two fixing members respectively fixed to inner walls of the housings of the first and second floats. The connecting module further includes a connecting rod having two ends respectively fixed to the two fixing members. 
         [0028]    The peripheral face of the rotor body may further include a third slot and a fourth slot. The at least one float further includes a third float and a fourth float opposed to the third float in a diametric direction of the rotor body. Each of the third and fourth floats is located between the first and second floats. The third float includes a housing. The housing of the third float has an open end and is received in the third slot. The open end of the housing of the third float faces the interior of the rotor body. The third float further includes an isolating member connecting the housing of the third float to the rotor body. The isolating member of the third float seals the third slot. The fourth float includes a housing. The housing of the fourth float has an open end and is received in the fourth slot. The open end of the housing of the fourth float faces the interior of the rotor body. The fourth float further includes an isolating member connecting the housing of the fourth float to the rotor body. The isolating member of the fourth float seals the fourth slot. 
         [0029]    A connecting module may be connected between the third and fourth floats. The connecting module includes two fixing members respectively fixed to inner walls of the housings of the third and fourth floats. The connecting module further includes a connecting rod having two ends respectively fixed to the two fixing members. 
         [0030]    Each of the at least one slidewheel unit may include a first slidewheel unit, a positioning unit and a pivoting unit. The first slidewheel unit is mounted to an outer surface of the housing of the respective one of the at least one float. The positioning unit is connected to the rotor body and includes a second slidewheel unit. The pivoting unit is connected to the rotor body. A connecting rope is wound around the first and second slidewheel units and connected to the pivoting unit. The pivoting unit starts to pivot when making contact with the guiding track. The pivoting unit pulls the connecting rope to control the telescopic movement of the respective one of the at least one float. 
         [0031]    The housing may include a liquid breaking portion in a front end of the housing in a rotating direction of the rotor. The liquid breaking portion has an protruding edge. The protruding edge has two side faces meeting each other at a center of the protruding edge and respectively connecting to two lateral edges of the housing. 
         [0032]    The rotor may further include a plurality of outer tracks respectively mounted to the first and second end faces of the rotor body. The outer surface of the housing of the float has two sides provided with a plurality of limiting members. Each of the plurality of limiting members is movably mounted in a corresponding one of the plurality of outer tracks. Furthermore, the positioning unit may include a positioning support having two ends respectively fixed to two adjacent ones of the plurality of outer tracks, permitting the positioning support to stretch over the peripheral face of the rotor body. Moreover, the plurality of outer tracks includes a plurality of first outer tracks connected to the first end face of the rotor body, as well as a plurality of second outer tracks connected to the second end face of the rotor body. The plurality of first outer tracks is connected by a ring, and the plurality of second outer tracks is connected by another ring. 
         [0033]    The second slidewheel unit is mounted to the positioning support and may be diametrically opposed to the first slidewheel unit. 
         [0034]    The positioning unit may further include a third slidewheel unit. The connecting rope that passes through the second slidewheel unit is connected to the third slidewheel unit and is diverted to a lateral side of the respective one of the at least one float by the third slidewheel unit. 
         [0035]    The pivoting unit may include a rocking arm and a fourth slidewheel unit. The rocking arm is pivotally connected to the peripheral face of the rotor body. The fourth slidewheel unit is mounted to the rocking arm. The connecting rope is wound around and passes through the first slidewheel unit, the second slidewheel unit, the third slidewheel unit and the fourth slidewheel unit in sequence. The connecting rope is fixed to the rotor. 
         [0036]    The pivoting unit may include a rolling member rotatably mounted to a free end of the rocking arm. The rolling member moves along the guiding track. 
         [0037]    Alternatively, the pivoting unit may include a pivoting frame, a rocking arm and a rolling member. The pivoting frame is pivotally connected to the peripheral face of the rotor body. The connecting rope is wound around and passes through the first slidewheel unit and the second slidewheel unit in sequence. The connecting rope is fixed to the pivoting frame. The rocking arm is fixed to the pivoting frame. The rolling member is rotatably mounted to a free end of the rocking arm and moves along the guiding track. 
         [0038]    The isolating member is made of an elastic leakproof material. An end of the isolating member is fixed to the peripheral face of the rotor body, and another end of the isolating member is fixed to an outer face of the housing. 
         [0039]    The outer surface of the housing is arcuate and has a curvature corresponding to a curvature of the peripheral face of the rotor body. The outer surface of the housing and the peripheral face of the rotor body form a continuous arcuate face when the housing retracts into the interior of the rotor body in a maximal extension magnitude. 
         [0040]    The invention further provides a method for generating kinetic energy using the buoyancy-driven kinetic energy generating apparatus, which comprises filling a liquid into the tank to provide the rotor body with a pre-buoyancy, and controlling the at least one float to telescope relative to the rotor body, causing a change in local buoyancy of the rotor body to imbalance the rotor body and to cause rotation of the rotor body about the rotating axis. Each of the at least one float completes a telescopic cycle while the float rotates a turn together with the rotor body about the rotating axis. The telescopic cycle includes a float hidden stroke, a float gradual extending stroke, a float completely exposed stroke and a float gradual retracting stroke in sequence. The tank includes a float hidden section, a float gradual extending section, a float completely exposed section and a float gradual retracting section in sequence in a rotating direction of the rotor. The float hidden section corresponds to the float hidden stroke. Each of the at least one float maintains in a maximal retraction state having a maximal retraction magnitude when located in the float hidden section. When each of the at least one float is driven by the rotating rotor body to move from the float hidden section into the float gradual extending section, the float undergoes the float gradual extending stroke, and the extension magnitude of the float increases gradually until the float enters the float completely exposed section where the extension magnitude of the float is maximal. The float completely exposed section corresponds to the float completely exposed stroke. Each of the at least one float undergoes the float completely exposed stroke in the float completely exposed section and maintains a maximal extension magnitude to drive the rotor body to rotate. Each of the at least one float is driven by the rotating rotor body to move from the float completely exposed section into the float gradual retracting section. When the float undergoes the float gradual retracting stroke, the extension magnitude of the float decreases gradually in the float gradual retracting section until the float enters the float hidden section and then undergoes the float hidden stroke in the maximal retraction state. 
         [0041]    The float gradual extending section is located below a level of the liquid, and the float gradual retracting section is located above the level of the liquid. 
         [0042]    The float gradual extending section may be located between a vertical line and a horizontal line. Each of the vertical and horizontal lines passes through the rotating center of the rotor body. 
         [0043]    The float hidden section may be opposite to the float completely exposed section in a diametric direction of the rotor body, and the float gradual extending section may be opposite to the float gradual retracting section in a diametric direction of the rotor body. Furthermore, the float hidden section, the float gradual extending section, the float completely exposed section and the float gradual retracting section extend through a same angle. 
         [0044]    The at least one float may include a first float and a second float opposed to the first float in a diametric direction of the rotor body. One of the first and second floats undergoes the float hidden stroke while another of the first and second floats undergoes the float completely exposed stroke. One of the first and second floats undergoes the float gradual extending stroke while the other of the first and second floats undergoes the float gradual retracting stroke. 
         [0045]    The extension magnitude of the at least one float forms an arcuate path during the float gradual extending stroke, the float completely exposed stroke and the float gradual retracting stroke. The extension magnitude of the at least one float forms an arcuate path having increasing radiuses of curvature along with rotational movement of the rotor body about the rotating axis during the float gradual extending stroke. The extension magnitude of the at least one float forms an arcuate path having a uniform radius of curvature along with the rotational movement of the rotor body during the float completely exposed stroke. The extension magnitude of the at least one float forms an arcuate path having decreasing radiuses of curvature along with the rotational movement of the rotor body during the float gradual retracting stroke. 
         [0046]    Thus, the buoyancy-driven kinetic energy generating apparatus of the invention has increased total buoyancy and has a lower resistance during operation, allowing smooth operation of the buoyancy-driven kinetic energy generating apparatus to enhance the kinetic energy generating efficiency. Furthermore, the buoyancy-driven kinetic energy generating apparatus has a simple structure to reduce the costs of manufacture, assembly, and maintenance. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0047]      FIG. 1  is a schematic view of a conventional buoyancy-driven kinetic energy generating device. 
           [0048]      FIG. 2  is a perspective view of a buoyancy-driven kinetic energy generating apparatus of a first embodiment according to the present invention, with a portion of the buoyancy-driven kinetic energy generating apparatus cut away. 
           [0049]      FIG. 3  is a cross sectional view of the buoyancy-driven kinetic energy generating apparatus of the first embodiment according to the present invention. 
           [0050]      FIG. 4  is a partial, exploded perspective view of a float of the first embodiment according to the present invention. 
           [0051]      FIG. 5  is an enlarged view of a portion of the float according to the present invention, with the float in an extended position, and with an isolating member unstretched. 
           [0052]      FIG. 6  is an enlarged view of the portion of the float according to the present invention, with the float in a retracted position, and with the isolating member stretched. 
           [0053]      FIG. 7  is a schematic diagram illustrating the extension magnitude of the float when a rotor according to the present invention rotates in a clockwise direction. 
           [0054]      FIG. 8  is a first operational state of the first embodiment according to the present invention having a single float. 
           [0055]      FIG. 9  is a second operational state of the first embodiment according to the present invention having a single float. 
           [0056]      FIG. 10  is a third operational state of the first embodiment according to the present invention having a single float. 
           [0057]      FIG. 11  is a fourth operational state of the first embodiment according to the present invention having a single float. 
           [0058]      FIG. 12  is a first operational state of the first embodiment according to the present invention having three floats. 
           [0059]      FIG. 13  is a second operational state of the first embodiment according to the present invention having three floats. 
           [0060]      FIG. 14  is a third operational state of the first embodiment according to the present invention having three floats. 
           [0061]      FIG. 15  is a partial, exploded, perspective view of a buoyancy-driven kinetic energy generating apparatus of a second embodiment according to the present invention. 
           [0062]      FIG. 16  is a first operational state of the second embodiment according to the present invention having two floats. 
           [0063]      FIG. 17  is a partial, side view of one of the floats of the second embodiment according to the present invention, with the float extending and retracting under guidance of two tracks. 
           [0064]      FIG. 18  is a second operational state of the second embodiment according to the present invention having two floats. 
           [0065]      FIG. 19  is a third operational state of the second embodiment according to the present invention having two floats. 
           [0066]      FIG. 20  is a fourth operational state of the second embodiment according to the present invention having two floats. 
           [0067]      FIG. 21  is a first operational state of a buoyancy-driven kinetic energy generating apparatus of a third embodiment according to the present invention having two floats. 
           [0068]      FIG. 22  is a first operational state of a buoyancy-driven kinetic energy generating apparatus of a fourth embodiment according to the present invention having four floats. 
           [0069]      FIG. 23  is a second operational state of the fourth embodiment according to the present invention having four floats. 
           [0070]      FIG. 24  is an operational state of a buoyancy-driven kinetic energy generating apparatus of a fifth embodiment according to the present invention having four floats. 
           [0071]      FIG. 25  is a schematic diagram illustrating the extension magnitude of the float when a rotor according to the present invention rotates in a counterclockwise direction. 
           [0072]      FIG. 26  is an operational state of a sixth embodiment according to the present invention having four floats. 
           [0073]      FIG. 27  is a perspective view of a buoyancy-driven kinetic energy generating apparatus of the sixth embodiment according to the present invention, with a portion of the buoyancy-driven kinetic energy generating apparatus cut away. 
           [0074]      FIG. 28  is a perspective view of the buoyancy-driven kinetic energy generating apparatus according to the present invention, with the omission of the auxiliary positioning unit. 
           [0075]      FIG. 29  is a perspective view of the buoyancy-driven kinetic energy generating apparatus of the sixth embodiment according to the present invention, which shows an operational state before the rolling member enters the movement control section of the guiding track. 
           [0076]      FIG. 30  is a perspective view of the buoyancy-driven kinetic energy generating apparatus of the sixth embodiment according to the present invention, which shows an operational state after the rolling member enters the movement control section of the guiding track. 
           [0077]      FIG. 31  is a perspective view of the buoyancy-driven kinetic energy generating apparatus of the sixth embodiment according to the present invention, which shows an operational state after the rolling member enters the maintaining section of the guiding track. 
           [0078]      FIG. 32  is an operational state of a seventh embodiment according to the present invention having four floats. 
           [0079]      FIG. 33  is a perspective view of a buoyancy-driven kinetic energy generating apparatus of the seventh embodiment according to the present invention, with a portion of the buoyancy-driven kinetic energy generating apparatus cut away. 
           [0080]      FIG. 34  is a perspective view of the buoyancy-driven kinetic energy generating apparatus of the seventh embodiment according to the present invention, which shows an operational state before the rocking arm makes contact with the guiding track. 
           [0081]      FIG. 35  is a perspective view of the buoyancy-driven kinetic energy generating apparatus of the seventh embodiment according to the present invention, which shows an operational state when the rocking arm makes contact with the guiding track. 
           [0082]      FIG. 36  is a perspective view of the buoyancy-driven kinetic energy generating apparatus of the seventh embodiment according to the present invention, which shows an operational state after the rolling member enters the movement control section of the guiding track. 
           [0083]      FIG. 37  is a perspective view of the buoyancy-driven kinetic energy generating apparatus of the seventh embodiment according to the present invention, which shows an operational state when the rolling member enters the maintaining section of the guiding track. 
           [0084]      FIG. 38  is a schematic diagram illustrating the extension magnitude of the float when a rotor according to the seventh embodiment of the present invention rotates in a counterclockwise direction. 
           [0000]    
         
           
                 
               
                 
                 
                 
                 
               
                 
               
                 
                 
                 
                 
               
             
                 
                     
                 
               
               
                 
                   (the present invention) 
                 
               
            
             
                 
                   1 
                   base 
                   11 
                   tank 
                 
                 
                   111 
                   support 
                   12 
                   shaft fixing portion 
                 
                 
                   2 
                   rotor 
                   21 
                   rotor body 
                 
                 
                   21a 
                   end face 
                   21b 
                   peripheral face 
                 
                 
                   211 
                   slot 
                   211a 
                   first slot 
                 
                 
                   211b 
                   second slot 
                   211c 
                   third slot 
                 
                 
                   211d 
                   fourth slot 
                   22 
                   shaft portion 
                 
                 
                   22a 
                   shaft 
                   22b 
                   shaft 
                 
                 
                   221 
                   shaft hole 
                   23 
                   outer track 
                 
                 
                   24 
                   ring 
                   3a, 3p 
                   first float 
                 
                 
                   3 
                   float 
                   3r 
                   third float 
                 
                 
                   3b, 3c, 3q 
                   second float 
                   31 
                   housing 
                 
                 
                   3s 
                   fourth float 
                   32 
                   isolating member 
                 
                 
                   311 
                   liquid breaking portion 
                   331 
                   roller 
                 
                 
                   33 
                   guiding member 
                   35 
                   connecting module 
                 
                 
                   34 
                   limiting member 
                   352 
                   connecting rod 
                 
                 
                   351 
                   fixing member 
                   411 
                   positioning member 
                 
                 
                   4 
                   telescopic movement control  
                   42a 
                   first balancing unit 
                 
                 
                     
                   module 
                   421 
                   first support seat 
                 
                 
                   41 
                   control guiding member 
                   422 
                   second support seat 
                 
                 
                   412 
                   first maintaining section 
                   423 
                   elastic returning  
                 
                 
                   413 
                   first movement control section 
                     
                   member 
                 
                 
                   414 
                   second maintaining section 
                   52 
                   rail 
                 
                 
                   415 
                   second movement control  
                   52b 
                   terminal end 
                 
                 
                     
                   section 
                   522 
                   maintaining section 
                 
                 
                   42 
                   balancing unit 
                   61a 
                   start end 
                 
                 
                   42b 
                   second balancing unit 
                   611 
                   movement control  
                 
                 
                   4211 
                   sleeve 
                     
                   section 
                 
                 
                   4221 
                   axle 
                   62 
                   fastener 
                 
                 
                   5 
                   telescopic movement control  
                   71a 
                   start end 
                 
                 
                     
                   module 
                   711 
                   abutment face 
                 
                 
                   51 
                   bracket 
                   713 
                   maintaining section 
                 
                 
                   52a 
                   start end 
                   721 
                   first slidewheel unit 
                 
                 
                   521 
                   movement control section 
                   7221 
                   positioning support 
                 
                 
                   53 
                   passage 
                   723 
                   pivoting unit 
                 
                 
                   6 
                   telescopic movement control  
                   7232 
                   rocking arm 
                 
                 
                     
                   module 
                   724 
                   auxiliary positioning  
                 
                 
                   61 
                   pressing board 
                     
                   unit 
                 
                 
                   61b 
                   terminal end 
                   7242 
                   tension wheel 
                 
                 
                   612 
                   maintaining section 
                   81a 
                   start end 
                 
                 
                   7 
                   telescopic movement control  
                   811 
                   abutment face 
                 
                 
                     
                   module 
                   813 
                   maintaining section 
                 
                 
                   71 
                   guiding track 
                   821 
                   first slidewheel unit 
                 
                 
                   71b 
                   terminal end 
                   8221 
                   positioning support 
                 
                 
                   712 
                   movement control section 
                   8223 
                   third slidewheel unit 
                 
                 
                   72 
                   slidewheel unit 
                   8231 
                   rocking arm 
                 
                 
                   722 
                   positioning unit 
                   8233 
                   rolling member 
                 
                 
                   7222 
                   second slidewheel unit 
                   F1 
                   maximal level 
                 
                 
                   7231 
                   pivoting frame 
                   F3 
                   middle level 
                 
                 
                   7233 
                   rolling member 
                   R 
                   connecting rope 
                 
                 
                   7241 
                   auxiliary positioning support 
                   Z1 
                   float hidden section 
                 
                 
                   73 
                   bracket 
                     
                     
                 
                 
                   8 
                   telescopic movement control  
                     
                     
                 
                 
                     
                   module 
                     
                     
                 
                 
                   81 
                   guiding track 
                     
                     
                 
                 
                   81b 
                   terminal end 
                     
                     
                 
                 
                   812 
                   movement control section 
                     
                     
                 
                 
                   82 
                   slidewheel unit 
                     
                     
                 
                 
                   822 
                   positioning unit 
                     
                     
                 
                 
                   8222 
                   second slidewheel unit 
                     
                     
                 
                 
                   823 
                   pivoting unit 
                     
                     
                 
                 
                   8232 
                   fourth slidewheel unit 
                     
                     
                 
                 
                   F 
                   level 
                     
                     
                 
                 
                   F2 
                   minimal level 
                     
                     
                 
                 
                   L1, L1′,  
                   telescopic movement end line 
                     
                     
                 
                 
                   L1″ 
                     
                     
                     
                 
                 
                   L2, L2′,  
                   telescopic movement start line 
                     
                     
                 
                 
                   L2″ 
                     
                     
                     
                 
                 
                   L3 
                   telescopic movement end line 
                     
                     
                 
                 
                   L4 
                   telescopic movement start line 
                     
                     
                 
                 
                   P1 , P2,  
                   connection 
                     
                     
                 
                 
                   P3, P4 
                     
                     
                     
                 
                 
                   V 
                   vertical line 
                     
                     
                 
                 
                   Z2 
                   float gradual extending section 
                     
                     
                 
                 
                   Z3 
                   float completely exposed  
                     
                     
                 
                 
                     
                   section 
                     
                     
                 
                 
                   Z4 
                   float gradual retracting section 
                     
                     
                 
               
            
             
                 
                   (Prior Art) 
                 
               
            
             
                 
                   9 
                   buoyancy-driven kinetic  
                   92 
                   conveyor 
                 
                 
                     
                   energy generating device 
                   93 
                   rotary shaft 
                 
                 
                   91 
                   tower 
                   95 
                   bubble supply  
                 
                 
                   921 
                   bucket 
                     
                   means 
                 
                 
                   94 
                   generator 
                 
                 
                     
                 
               
            
           
         
       
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0085]    The above objectives and other objectives, features and advantages of the present invention will become clearer in light of the following detailed description of illustrative embodiments of this invention described in connection with the drawings. 
         [0086]      FIG. 2  shows a buoyancy-driven kinetic energy generating apparatus of a first embodiment according to the present invention. The buoyancy-driven kinetic energy generating apparatus generally includes a base  1 , a rotor  2 , at least one float  3 , and a telescopic movement control module  4 . The rotor  2  is rotatably mounted to the base  1 . The at least one float  3  is telescopically mounted to the rotor  2 . The telescopic movement control module  4  is mounted to the base  1  to control telescopic movement of the at least one float  3  relative to the rotor  2 . In the first embodiment of the present invention, the quantity of the at least one float  3  may be 1, and is labeled as “first float  3   a.”   
         [0087]    The base  1  is adapted to receive a flowable working medium, such as a liquid. The base  1  also provides assembling and positioning for the rotor  2  and the telescopic movement control module  4 . Specifically, the base  1  includes a tank  11  and two shaft fixing portions  12 . The tank  11  may receive the liquid. The shaft fixing portions  12  are respectively mounted to two opposite outer sides of the tank  11  respectively of two lateral walls of the tank  11 . The shaft fixing portions  12  are coaxial with each other. In this embodiment, each shaft fixing portion  12  is a board with a bearing. Furthermore, a support  111  is mounted to each outer side of the tank  11 , and a shaft fixing portion  12  is assembled and fixed to one of the outer sides of the tank  11  via one of the supports  111 . Leakage-proof gaskets (not shown) can be mounted between the tank  11  and the shaft fixing portions  12  to prevent leakage of the liquid, such that a portion of the rotor  2  can extend through the lateral walls of the tank  11  without liquid leakage. 
         [0088]    With reference to  FIGS. 2 and 3 , the rotor  2  is rotatably mounted to the base  1 . Specifically, the rotor  2  includes a rotor body  21  and a shaft portion  22 . The rotor body  21  includes a hollow interior for receiving a mass having a density smaller than a density of the liquid received in the tank  11 . The mass can be a gas or a solid (such as expandable polystyrene or low-density wood). Alternatively, the rotor body  21  can be directly made of a low-density solid, and the liquid received in the tank  11  can provide sufficiency buoyancy to make the rotor body  21  float. In this embodiment, the rotor body  21  is in the form of a cylindrical housing having a hollow interior such that the easiest-to-obtain air can directly be contained in the interior of the rotor body  21  to reduce the costs. The rotor body  21  includes two opposite end faces  21   a  and a peripheral face  21   b  connected between the end faces  21   a . A plurality of slots  211  is defined in the peripheral face  21   b . The number of the slots  211  corresponds to that of the floats  3 . For example, there is only one float  3  in this embodiment. Thus, only a first slot  211   a  is defined in the peripheral face  21   b.    
         [0089]    The shaft portion  22  of the rotor  2  extends through the end faces  21   a  of the rotor body  21  to connect the shaft fixing portions  12  of the base  1 , allowing the rotor body  21  to be received in the tank  11  and to rotate in the tank  11  about a rotating axis defined by the shaft portion  22  and passing a rotating center of the rotor body  21 . In this embodiment, the shaft portion  22  includes two coaxially located shafts  22   a  and  22   b , with each shaft  22   a ,  22   b  having a shaft hole  221 . Each shaft  22   a ,  22   b  includes an end mounted to one of the end faces  21   a  of the rotor body  21 . The other end of each shaft  22   a ,  22   b  extends through the tank  11  and is connected to one of the shaft fixing portions  12 . Thus, the interior of the rotor body  21  intercommunicates with the outside of the tank  11  via the shaft holes  221 . By such an arrangement, the rotor body  21  of the rotor  2  can rotate in the tank  11  relative to the base  1  while the interior of the rotor body  21  is empty for receiving other components to reduce limitation to the spatial arrangement of the components. Furthermore, the overall weight of the rotor  2  can be reduced to increase convenience during assembly. Furthermore, the shaft portion  22  can be in the form of a single shaft extending through the rotor body  21  while allowing the rotor body  21  to rotate in the tank  11  relative to the base  1 , which can be appreciated and can be modified by one having ordinary skill in the art. The present invention is not limited to the embodiment shown. Furthermore, the rotor  2  can include a plurality of outer tracks  23  respectively mounted to the end faces  21   a  of the rotor body  21  (namely, the plurality of outer tracks  23  is connected to the rotor body  21 ) to guide the telescopic movement of the first float  3   a.    
         [0090]    The first float  3   a  is telescopically mounted to the rotor body  21 . In the embodiment shown in  FIGS. 2 and 3 , the first float  3   a  is mounted to the peripheral face  21   b  of the rotor body  21  to telescopically move in a radial direction of the rotor body  21  perpendicular to the rotating axis of the rotor body  21 . Specifically, with reference to  FIGS. 3 and 4 , the first float  3   a  includes a housing  31  and an isolating member  32 . An interior of the housing  31  provides a space with a predetermined volume. The housing  31  has an open end. When the housing  31  is mounted in the first slot  211   a  of the rotor body  21 , the open end of the housing  31  faces the interior of the rotor body  21 . Furthermore, the housing  31  is connected to the rotor body  21  via the isolating member  32  to assure that the interior space of the rotor body  21  is isolated from the liquid in the tank  11 . 
         [0091]    In this embodiment, the isolating member  32  is made of an elastic leakproof material. An end of the isolating member  32  is fixed to the peripheral face  21   b  of the rotor body  21 . The other end of the isolating member  32  is fixed to an outer face of the housing  31  such that the liquid in the tank  11  will not leak into the housing  31  and the rotor body  21 . Furthermore, the connection between the isolating member  32  and the rotor body  21  is gapless and can be achieved by, for example, gluing, and several fasteners (not shown) can be provided tighten the isolating member  32  and the rotor body  21  to increase the engagement reliability. By such an arrangement, with reference to  FIG. 5 , when the first float  3   a  is in an unretracted state (or is extending) relative to the peripheral face  21   b  of the rotor body  21 , the isolating member  32  is in an unstretched state (or gradually returns to the unstretched state). On the other hand, with reference to  FIG. 6 , when the first float  3   a  retracts relative to the peripheral face  21   b  of the rotor body  21 , the isolating member  32  can be continuously stretched and undergo elastic deformation. Thus, the magnitude of the telescopic movement of the housing  31  of the first float  3   a  relative to the rotor body  21  can be increased by the isolating member  32 . 
         [0092]    Still referring to  FIGS. 3 and 4 , the outer surface of the housing  31  can be arcuate and preferably has a curvature corresponding to a curvature of the peripheral face  21   b  of the rotor body  21 . Thus, when the housing  31  retracts into the interior of the rotor body  21 , the outer surface of the housing  31  and the peripheral face  21   b  of the rotor body  21  can form a continuous arcuate face to reduce the resistance while entering the liquid. The housing  31  further includes a liquid breaking portion  311  in a front end of the housing  31  in the rotating direction. The liquid breaking portion  311  has an protruding edge. The protruding edge have two side faces meeting each other at a center of the protruding edge and respectively connect to two lateral edges of the housing  31 . The liquid breaking portion  311  reduces the resistance when the first float  3   a  floats upward and increases the floating speed. Furthermore, the first float  3   a  further includes a guiding member  33  and a plurality of limiting member  34  on the outer surface of the housing  31 . Optionally, the guiding member  33  may be mounted on a center of the outer surface of the housing  31 . Preferably, the length of the guiding member  33  is adjustable. A roller  331  is mounted to a free end of the guiding member  33 . When the guiding member  33  contacts the telescopic movement control module  4 , the roller  331  smoothly and continuously moves on the telescopic movement control module  4 . The limiting members  34  can be located adjacent to two lateral edges of the outer surface of the housing  31  and are respectively restrained in the outer tracks  23 , such that the housing  31  are restricted and can only move along a guiding direction provided by the outer tracks  23 . 
         [0093]    With reference to  FIGS. 2, 3, and 4 , the telescopic movement control module  4  is mounted in the tank  11  of the base  1  to control the telescopic movement of the first float  3   a  relative to the rotor body  21  during rotation of the rotor body  21 . In this embodiment, the telescopic movement control module  4  includes a control guiding member  41  and a first balancing unit  42   a . The control guiding member  41  is mounted to an inner wall of the tank  11 . The first balancing unit  42   a  is mounted between the first float  3   a  and the rotor body  21  to actuate the first float  3   a . The first balancing unit  42   a  balances forces imparted to the inner and outer sides of the first float  3   a , maintaining contact between the first float  3   a  and the control guiding member  41 . 
         [0094]    Specifically, the control guiding member  41  is substantially a ring and includes a plurality of positioning members  411  fixed to the inner wall of the tank  11  such that the control guiding member  41  is received in the tank  11  and surrounds the rotor body  21 . To increase the assembling convenience, the control guiding member  41  can be comprised of a plurality of arcuate boards coupled to each other, with the arcuate boards having the same or different lengths, which can be modified by one having ordinary skill in the art according to needs. The present invention is not limited to the embodiment shown. 
         [0095]    The control guiding member  41  includes a first maintaining section  412 , a first movement control section  413 , a second maintaining section  414 , and a second movement control section  415 , with the first maintaining section  412 , the first movement control section  413 , the second maintaining section  414 , and the second movement control section  415  connected to each other in sequence. The second movement control section  415  is connected to the first maintaining section  412 , such that the control guiding member  41  includes a continuous, closed, annular inner surface. The inner surface of the first maintaining section  412  and the inner surface of the second maintaining section  414  are concentric to the peripheral face  21   b  of the rotor body  21 . A radius of curvature of the first maintaining section  412  is smaller than a radius of curvature of the second maintaining section  414 . A spacing between the inner surface of the first movement control section  413  and the rotating center of the rotor body  21  increases from a connection end of the first movement control section  413  connected to the first maintaining section  412  towards another connection end of the first movement control section  413  connected to the second maintaining section  414 . A spacing between the inner surface of the second movement control section  415  and the rotating center of the rotor body  21  decreases from a connection end of the second movement control section  415  connected to the second maintaining section  414  towards another connection end of the second movement control section  415  connected to the first maintaining section  412 . 
         [0096]    The first maintaining section  412  is connected to the second movement control section  415  at a connection P 1 . The first movement control section  413  is connected to the second maintaining section  414  at a connection P 2 . A line section passing through the connection P 1  and the rotating center of the rotor body  21  and another line section passing through the connection P 2  and the rotating center of rotor body  21  together define a telescopic movement end line L 1 . Preferably, the connections P 1  and P 2  are opposed to each other in a diametric direction of the rotor body  21  such that the telescopic movement end line L 1  is rectilinear. Furthermore, the first maintaining section  412  is connected to the first movement control section  413  at a connection P 3 . The second maintaining section  414  is connected to the second movement control section  415  at a connection P 4 . A line section passing through the connection P 3  and the rotating center of the rotor body  21  and another line section passing through the connection P 4  and the rotating center of rotor body  21  together define a telescopic movement start line L 2 . Preferably, the connections P 3  and P 4  are opposed to each other in a diametric direction of the rotor body  21  such that the telescopic movement start line L 2  is rectilinear. Furthermore, the telescopic movement end line L 1  is orthogonal to the telescopic movement start line L 2 . 
         [0097]    With reference to  FIGS. 3 and 4 , the first balancing unit  42   a  includes a first support seat  421 , a second support seat  422 , and an elastic returning member  423 . The first support seat  421  is fixed to an inner wall of the rotor body  21 . The second support seat  422  is fixed to an inner wall of the housing  31  of the first float  3   a . Furthermore, the second support seat  422  is movable relative to the first support seat  421  in a radial direction of the rotor body  21 . As an example, the first support seat  421  includes a sleeve  4211 . The second support seat  422  includes an axle  4221  movably received in the sleeve  4211 . Alternatively, the axle can be provided on the first support seat  421 , and the sleeve can be provided on the second support seat  422 . 
         [0098]    The elastic returning member  423  is a member with elastic deforming capacity, such as a spring or a resilient plate. Two ends of the elastic returning member  423  respectively press against the first support seat  421  and the second support seat  422  to balance the forces exerted on the inner and outer sides of the first float  3   a . When the first float  3   a  is pushed by the control guiding member  41 , the elastic returning member  423  presses against the second support seat  422  such that the first float  3   a  keeps contacting the control guiding member  41 . On the other hand, when the first float  3   a  is pulled by the control guiding member  41 , the elastic returning member  423  pulls the second support seat  422  such that the first float  3   a  keeps contacting the control guiding member  41 . In this embodiment, the elastic returning member  423  is in the form of a compression spring mounted around the sleeve  4211 . The sleeve  4211  assures that the elastic returning member  423  merely has axial deformation. In other embodiments, the first balancing unit  42   a  can include electrically controlled components or hydraulic or pneumatic cylinder components for actuating the first float  3   a.    
         [0099]    Please refer reference to  FIG. 3  and  FIG. 7 .  FIG. 7  is a schematic diagram illustrating the extension magnitude of the first float  3   a  when the rotor  2  according to the present invention rotates in a clockwise direction. The hatching area in  FIG. 7  indicates the extension magnitude of the first float  3   a  in the tank  11 . When the buoyancy-driven kinetic energy generating apparatus operates, the first float  3   a  completes a telescopic cycle relative to the peripheral face  21   b  of the rotor body  21  while the first float  3   a  rotates a round together with the rotor body  21 . Each telescopic cycle includes four strokes: a float hidden stroke, a float gradual extending stroke, a float completely exposed stroke, and a float gradual retracting stroke. The first float  3   a  maintains in a state having the maximal retraction magnitude (i.e., the extension magnitude is minimal) during the float hidden stroke. The extension magnitude of the first float  3   a  increases gradually during the float gradual extending stroke. The first float  3   a  maintains in a state having the maximal extension magnitude during the float completely exposed stroke. The extension magnitude of the first float  3   a  gradually decreases during the float gradual retracting stroke. The first float  3   a  has the maximal retraction magnitude when the first float  3   a  returns to the float hidden stroke. 
         [0100]    The telescopic movement end line L 1  and the telescopic movement start line L 2  divide the movement plane into four sections (starting from the telescopic movement end line L 1  in the rotating direction of the rotor  2 ): a float hidden section Z 1 , a float gradual extending section Z 2 , a float completely exposed section Z 3 , and a float gradual retracting section Z 4 . The float hidden section Z 1 , the float gradual extending section Z 2 , the float completely exposed section Z 3 , and the float gradual retracting section Z 4  respectively correspond to the float hidden stroke, the float gradual extending stroke, the float completely exposed stroke, and the float gradual retracting stroke. Namely, the float hidden section Z 1 , the float gradual extending section Z 2 , the float completely exposed section Z 3 , and the float gradual retracting section Z 4  respectively correspond to the first maintaining section  412 , the first movement control section  413 , the second maintaining section  414 , and the second movement control section  415  of the control guiding member  41 , such that the first float  3   a  can undergo the float hidden stroke, the float gradual extending stroke, the float completely exposed stroke, and the float gradual retracting stroke. Furthermore, the liquid contained in the tank  11  preferably has a level F at the upper portion of the rotor body  21  where the telescopic movement end line L 1  passes the rotor body  21  (see point C in  FIG. 7 ), such that the float gradual extending section Z 2  is located below the level F and such that the float gradual retracting section Z 4  is located above the level F. This assures that when the first float  3   a  enters the float gradual retracting section Z 4 , the first float  3   a  can smoothly retract into the interior of the rotor body  21  in the air without resistance caused by the liquid and can enter the liquid in the maximal retraction state. The resistance to the rotation of the rotor body  21  at the moment the first float  3   a  entering the liquid and affected by the liquid resistance can be reduced, enhancing the overall kinetic energy generating efficiency of the buoyancy-driven kinetic energy generating apparatus. 
         [0101]    By such an arrangement, the float hidden stroke of the first float  3   a  corresponds to the float hidden section Z 1  and maintains the maximal retraction magnitude (i.e., the minimal extension magnitude). When the first float  3   a  is driven by the rotating rotor body  21  to move from the float hidden section Z 1  into the float gradual extending section Z 2 , the first float  3   a  undergoes the float gradual extending stroke, and the extension magnitude of the first float  3   a  increases gradually until the first float  3   a  enters the float completely exposed section Z 3  where the extension magnitude of the first float  3   a  is maximal. The first float  3   a  undergoes the float completely exposed stroke in the float completely exposed section and maintains its maximal extension magnitude to drive the rotor body  21  to rotate. The first float  3   a  is driven by the rotating rotor body  21  to move from the float completely exposed section Z 3  into the float gradual retracting section Z 4 . Next, the first float  3   a  undergoes the float gradual retracting stroke, and the extension magnitude of the float decreases gradually in the float gradual retracting section Z 4  until the first float  3   a  enters the float hidden section Z 1  and then undergoes the float hidden stroke in its maximal retraction state. 
         [0102]    Accordingly, the extension magnitude of the first float  3   a  (the travel of the roller  331 ) of the present invention forms an arcuate path during the float gradual extending stroke, the float completely exposed stroke, and the float gradual retracting stroke. The arcuate path effectively reduces the rotational resistance to the rotor body  21  and maintains smooth rotation of the rotor body  21 . In this embodiment, during the float gradual extending stroke of the first float  3   a , the extension magnitude of the first float  3   a  (the travel of the roller  331 ) forms an arcuate path having increasing radiuses of curvature along with the rotational movement of the rotor body  21 . During the float completely exposed stroke of the first float  3   a , the extension magnitude of the first float  3   a  (the travel of the roller  331 ) forms an arcuate path having a uniform radius of curvature along with the rotational movement of the rotor body  21 . During the float gradual retracting stroke of the first float  3   a , the extension magnitude of the first float  3   a  (the travel of the roller  331 ) forms an arcuate path having decreasing radiuses of curvature along with the rotational movement of the rotor body  21 . 
         [0103]    With reference to  FIG. 3 , in the buoyancy-driven kinetic energy generating apparatus of the first embodiment according to the present invention, when the tank  11  has not been filled with a sufficient amount of liquid, the first float  3   a  can be set to be located in the float completely exposed section Z 3 , and the first balancing unit  42   a  presses against the housing  31 , such that the roller  331  of the guiding member  33  of the first float  3   a  contacts the second maintaining section  414  of the control guiding member  41 , with the first float  3   a  in the maximal extension state. With reference to  FIG. 8 , when the tank  11  is filled with a sufficient amount of liquid, the rotor body  21  can create a great pre-buoyancy in the liquid. At the same time, since the density of the air in the interior space of the housing  31  is smaller than the density of the liquid in the tank  11 , the first float  3   a  in the float completely exposed section Z 3  and having the maximal extension magnitude additionally and locally increases the buoyancy of the rotor body  21  to imbalance the rotor body  21 . As a result, the rotor body  21  starts to rotate. 
         [0104]    With reference to  FIG. 9 , after the first float  3   a  rotates jointly with the rotor body  21  and passes through the connection P 4  between the second maintaining section  414  and the second movement control section  415 , the control guiding member  41  starts to push the first float  3   a  by the second movement control section  415  to make the first float  3   a  undergo the float gradual retracting stroke, gradually reducing the extension magnitude of the first float  3   a  and gradually retracting the first float  3   a  into the interior of the rotor body  21 . The rotor body  21  continues its rotation, and the first float  3   a  emerges from the liquid to a position above the level F while the float enters the float gradual retracting section Z 4  in which the first float  3   a  continuously retracts into the interior of the rotor body  21 . The liquid breaking portion  311  of the first float  3   a  assists in reducing the resistance of the housing  31  moving in the liquid, increasing the rotational movement of the rotor body  21  carrying the first float  3   a  while reducing unnecessary loss of the kinetic energy to enhance the efficacy of the buoyancy-driven kinetic energy generating apparatus. 
         [0105]    With reference to  FIG. 10 , the first float  3   a  rotates jointly with the rotor body  21  and is gradually compressed to reduce the extension magnitude until the first float  3   a  moves to the connection P 1  between the second movement control section  415  and the first maintaining section  412 . Since the first float  3   a  at the connection P 1  has the maximal retraction magnitude, the first float  3   a  reenters the liquid with the minimal resistance and enters the float hidden section Z 1 . In the float hidden section Z 1 , the control guiding member  41  stops pushing the first float  3   a , and the first maintaining section  412  of the control guiding member  41  keeps the first float  3   a  in the state having the maximal retraction magnitude. 
         [0106]    After the first float  3   a  rotates jointly with the rotor body  21  and passes the connection P 3  between the first maintaining section  412  and the first movement control section  413 , the first balancing unit  42   a  presses against the housing  31  of the first float  3   a  to keep the roller  331  of the guiding member  33  of the first float  3   a  contacting the first movement control section  413  of the control guiding member  41 . Then, the first float  3   a  undergoes the float gradual extending stroke, and the extension magnitude of the first float  3   a  beyond the outer surface of the rotor body  21  increases gradually in the float gradual extending section Z 2 . Thus, the buoyancy is gradually increased to assist in rotation of the rotor body  21 . 
         [0107]    With reference to  FIG. 11 , finally, the first float  3   a  rotates jointly with the rotor body  21  and passes through the connection P 2  between the first control movement section  413  and the second maintaining section  414 . Then, the first float  3   a  reenters the float completely exposed section Z 3 , completing a telescopic cycle. 
         [0108]    In brief, in the buoyancy-driven kinetic energy generating apparatus of the first embodiment according to the present invention, the first balancing unit  42   a  keeps the first float  3   a  contacting the control guiding member  41 , and the first float  3   a  telescopes relative to the rotor body  21  under the guidance by the first maintaining section  412 , the first movement control section  413 , the second maintaining section  414 , and the second movement control section  415  to finish the float hidden stroke, the float gradual extending stroke, the float completely exposed stroke, and the float gradual retracting stroke in a telescopic cycle, providing assistance in rotation of the rotor body  21 . By such arrangement, when the shaft portion  22  of the rotor body  21  is connected to a generator or a device directly driven by shaft work, the buoyancy-driven kinetic energy generating apparatus according to the present invention can use buoyancy to generate kinetic energy, and the shaft portion  22  of the rotor body  21  drives the generator to generate electricity or directly actuates the shaft work-driven device, meeting the development trend of green energy. 
         [0109]    With reference to  FIG. 5 , note that the extension magnitude of the housing  31  of the first float  3   a  relative to the rotor body  21  is increased by the isolating member  32 . With reference to  FIG. 10 , during the float hidden stroke of the first float  3   a , the housing  31  of the first float  3   a  retracts to a position in which the outer surface of the housing  31  is flush with the outer surface of the rotor body  21  to form a continuous arcuate surface, reducing the resistance while entering the liquid. With reference to  FIG. 8 , during the float completely exposed stroke of the first float  3   a , the housing  31  of the first float  3   a  fully extends beyond the outer surface of the rotor body  21 , and the bottom end of the housing  31  of the first float  3   a  is also located outside of the outer surface of the rotor body  21  such that the housing  31  is merely connected to the rotor body  21  by the isolating member  32 . This increases the buoyancy of the first float  3   a  and, thus, enhances the operational efficiency of the buoyancy-driven kinetic energy generating apparatus. Furthermore, in a case that the buoyancy-driven kinetic energy generating apparatus includes only one first float  3   a  and it is difficult to reduce the friction between the components, to assure that the kinetic energy generated by the buoyancy-driven kinetic energy generating apparatus meets the expectation, a plurality of the buoyancy-driven kinetic energy generating apparatuses can be connected in series, and the first floats  3   a  of the buoyancy-driven kinetic energy generating apparatuses are located in different phase positions (i.e., the first floats  3   a  of the buoyancy-driven kinetic energy generating apparatuses are alternately disposed). The buoyancy-driven kinetic energy generating apparatuses can operate simultaneously to continuously provide assistance in rotation, increasing the operational efficiency of each buoyancy-driven kinetic energy generating apparatus. 
         [0110]    In other embodiments, the buoyancy-driven kinetic energy generating apparatus can include a plurality of floats  3  (odd-numbered or even-numbered floats  3 ) to continuously provide assistance in rotation of the rotor body  21 , increasing the operational efficiency of the buoyancy-driven kinetic energy generating apparatus. Preferably, the floats are provided on the peripheral face  21   b  of the rotor body  21  at regular intervals to further increase the stability during rotation of the rotor body  21 . 
         [0111]    In a non-restricting embodiment shown in  FIGS. 12-14 , the buoyancy-driven kinetic energy generating apparatus includes three floats (a first float  3   a  and two second floats  3   b  and  3   c ). The peripheral face  21   b  further includes two second slots  211   b  for receiving the two second floats  3   b  and  3   c . The telescopic movement control module  4  further includes a plurality of second balancing units  42   b . The second balancing units  42   b  are mounted in the interior of the rotor body  21  to respectively actuate the two second floats  3   b  and  3   c , maintaining the contact between the two second floats  3   a  and  3   b  and the control guiding member  41 . Thus, each of the first float  3   a  and the second floats  3   b  and  3   c  can complete a telescopic cycle relative to the peripheral face  21   b  of the rotor body  21  while the first and second floats  3   a ,  3   b  and  3   c  rotate a turn together with the rotor body  21 . In the state shown in  FIG. 12 , the first float  3   a  is at the connection P 2  between the first control movement section  413  and the second maintaining section  414 . Namely, the first float  3   a  has finished the float gradual extending stroke and is about to undergo the float completely exposed stroke (the first float  3   a  is about to move from the float gradual extending section Z 2  into the float completely exposed section Z 3 ). In this state, the extension magnitude of the first float  3   a  is maximal to provide assistance in rotation of the rotor  2 . At the same time, the second float  3   b  is in the float hidden section Z 1  and undergoes the float hidden stroke, with the second float  3   b  maintaining the maximal retraction magnitude to avoid resistance to rotation of the rotor  2 . The other second float  3   c  is located in the float gradual retracting section Z 4  and undergoes the float gradual retracting stroke during which the second float  3   c  gradually retracts into the interior of the rotor body  21 . By such an arrangement, the first float  3   a  can smoothly drive the rotor  2  to rotate. 
         [0112]    With reference to  FIG. 13 , next, the first float  3   a  leaves the float completely exposed section Z 3  and enters the float gradual retracting section Z 4 . At the same time, the second float  3   b  enters the float gradual extending section Z 2  and then the float completely exposed section Z 3  to take over assistance in rotation of the rotor  2 . With reference to  FIG. 14 , when the first float  3   a  leaves the float gradual retracting section Z 4  and enters the float hidden section Z 1 , the second float  3   c  enters the float gradual extending section Z 2  and then the float completely exposed section Z 3  to take over assistance in rotation of the rotor  2 . Thus, by sequential assistance in rotation of the rotor  2  from the first float  3   a , the second float  3   b , and the second float  3   c , the rotor  2  can easily overcome the friction between the components and maintains smooth rotation, enhancing the operational efficiency of the buoyancy-driven kinetic energy generating apparatus. 
         [0113]    With reference to  FIGS. 5 and 12 , note that the length of each float  3  (the first float  3   a , the second float  3   b , the second float  3   c ) can be reduced by provision of the isolating member  32 . Furthermore, during the float completely exposed stroke of each float  3 , the bottom of the housing  31  of the float  3  can extend beyond the outer surface of the rotor body  21 , and the housing  31  is still connected to the rotor body  21  by the isolating member  32 . Thus, the float  3  can generate buoyancy corresponding to the total area of the housing  31  and the isolating member  32  beyond the outer surface of the rotor body  21 . On the other hand, during the float hidden stroke of each float  3 , the housing  31  of the float  3  completely retracts into the rotor body  21  without occupying a large space. Thus, in the embodiment shown in  FIGS. 12-14 , the bottoms of the second support seats  422  of the balancing units  42  does not have to be close to the rotating center of the rotor body  21 , avoiding interference between the balancing units  42  to increase assembling convenience. 
         [0114]    With reference to  FIGS. 15 and 16 , a buoyancy-driven kinetic energy generating apparatus of a second embodiment according to the present invention generally includes a base  1 , a rotor  2 , two floats  3 , and a telescopic movement control module  5 . The second embodiment is substantially the same as the first embodiment. The main differences between the first and second embodiments are that the number of floats  3  in the second embodiment is two (i.e. the first float  3   p  and the second float  3   q ), and the first and second floats  3   p  and  3   q  are opposite to each other in a diametric direction of the rotor body  21  and can move synchronously in a radial direction relative to the rotor body  21 . The telescopic movement control module  5  may be different from the telescopic movement control module  4  in the first embodiment ( FIG. 2 ). 
         [0115]    Specifically, the buoyancy-driven kinetic energy generating apparatus of this embodiment includes the first float  3   p  and the second float  3   q . Thus, each end face  21   a  of the rotor body  21  includes a plurality of outer tracks  23  for respectively guiding the corresponding float  3 . Furthermore, the outer tracks  23  on the same end face  21   a  are connected by a ring  24  to reinforce the structural strength of the outer tracks  23 , reducing swaying or wobbling of the outer tracks  23  to enhance the stability of the telescopic movement of each float  3 . 
         [0116]    In the embodiment shown in  FIGS. 15 and 16 , the buoyancy-driven kinetic energy generating apparatus includes a connecting module  35  connecting the housing  31  of the first float  3   p  to the housing  31  of the second float  3   q . Thus, the first float  3   p  and the second float  3   q  can synchronously move in the radial direction relative to the rotor body  21 . In this embodiment, the guiding member  33  of each of the first float  3   p  and the second float  3   q  is substantially T-shaped. The connecting module  35  includes two fixing member  351  and a connecting rod  352 . The fixing members  351  are respectively mounted to the inner side of the first float  3   p  and the inner side of the second float  3   q . Two ends of the connecting rod  352  are mounted to the fixing members  351 . Preferably, the connecting rod  352  is connected to centers of the fixing members  351  to uniformly actuate the housings  31 . 
         [0117]    With reference to  FIGS. 16 and 17 , the telescopic movement control module  5  faces a portion of the peripheral face  21   b  of the rotor body  21 . As a non-restrictive example, the telescopic movement control module  5  in this embodiment is substantially aligned with a lower portion of the rotor body  21 . The telescopic movement control module  5  includes a bracket  51  and two rails  52 . The bracket  51  is mounted to the inner wall of the tank  11 . Each rail  52  is substantially arcuate. The rails  52  are mounted to the bracket  51  and are parallel to and spaced from each other to form a passage  53  therebetween. By such an arrangement, when the rotor body  21  rotates to make the guiding member  33  of the first float  3   p  or the second float  3   q  contact the rails  52 , the substantially T-shaped guiding member  33  can extend through the passage  53 , and the roller  331  of the guiding member  33  abutting outer surfaces of the rails  52 . The rails  52  control the movement of the guiding member  33  to control the first float  3   p  or the second float  3   q  to telescope relative to the peripheral face  21   b  of the rotor body  21  and to make the first float  3   p  and the second float  3   q  synchronously move relative to the rotor body  21  in the radial direction. 
         [0118]    With reference to  FIGS. 7 and 16 , when the buoyancy-driven kinetic energy generating apparatus operates, each of the first float  3   p  and the second float  3   q  rotates jointly with the rotor body  21   a  turn while completing a telescopic cycle relative to the peripheral face  21   b  of the rotor body  21 . Each telescopic cycle includes a float hidden stroke, a float gradual extending stroke, a float completely exposed stroke, and a float gradual retracting stroke. In this embodiment, the float hidden stroke, the float gradual extending stroke, the float completely exposed stroke, and the float gradual retracting stroke of each of the first float  3   p  and the second float  3   q  are preferably spaced from each other in a circumferential direction at regular intervals. The float hidden stroke of the first float  3   p  corresponds to the float completely exposed stroke of the second float  3   q . The float gradual extending stroke of the first float  3   p  corresponds to the float gradual retracting stroke of the second float  3   q . The float completely exposed stroke of the first float  3   p  corresponds to the float hidden stroke of the second float  3   q . The float gradual retracting stroke of the first float  3   p  corresponds to the float gradual extending stroke of the second float  3   q.    
         [0119]    Furthermore, each rail  52  includes a start end  52   a  and a terminal end  52   b . The extending direction from the start end  52   a  to the terminal end  52   b  of each rail  52  is substantially the rotating direction of the rotor  2 . Thus, the first float  3   p  and the second float  3   q  can enter the rails  52  via the start ends  52   a  of the rails  52  and can leave the rails  52  via the terminal ends  52   b  of the rails  52 . Each rail  52  includes a movement control section  521  and a maintaining section  522  following the movement control section  521  in the rotating direction of the rotor  2 . The spacing between the outer surface of the movement control section  521  to the rotating center of the rotor body  21  increases from a point of the movement control section  521  toward a connection between the movement control section  521  and the maintaining section  522 . The outer surface of the maintaining section  522  and the peripheral face  21   b  of the rotor body  21  are concentric. 
         [0120]    A telescopic movement end line L 1 ′ passes through the connection between the movement control section  521  and the maintaining section  522  and the rotating center of the rotor body  21  and is preferably at an angle of 45° to a horizontal line. A telescopic movement start line L 2 ′ passes through the rotating center of the rotor body  21  and is orthogonal to the telescopic movement end line L 1 ′. The telescopic movement end line L 1 ′ and the telescopic movement start line L 2 ′ divide the space of the tank  11  into four sections (starting from the telescopic movement end line L 1 ′ in the rotating direction of the rotor  2 ): a float hidden section Z 1 , a float gradual extending section Z 2 , a float completely exposed section Z 3 , and a float gradual retracting section Z 4 . Thus, the float hidden section Z 1  is opposite to the float completely exposed section Z 3  in a diametric direction of the rotor body  21 , and the float gradual extending section Z 2  is opposite to the float gradual retracting section Z 4  in a diametric direction of the rotor body  21 . Each of the first float  3   p  and the second float  3   q  can undergo the float hidden stroke, the float gradual extending stroke, the float completely exposed stroke, and the float gradual retracting stroke. 
         [0121]    Furthermore, the liquid contained in the tank  11  preferably has a level F at the upper portion of the rotor body  21  where the telescopic movement end line L 1 ′ passes the rotor body  21  (see point C′ in  FIG. 16 ), such that the float gradual extending section Z 2  is located below the level F and the float gradual retracting section Z 4  is located above the level F. This assures that when the first float  3   p  or the second float  3   q  enters the float gradual retracting section Z 4 , the first float  3   p  or the second float  3   q  can smoothly retract into the interior of the rotor body  21  in the air without resistance caused by the liquid and can enter the liquid at a state having the maximal retraction magnitude. The resistance to the rotation of the rotor body  21  at the moment the first float  3   p  or the second float  3   q  entering the liquid and affected by the liquid resistance can be reduced, enhancing the overall kinetic energy generating efficiency of the buoyancy-driven kinetic energy generating apparatus. 
         [0122]    With reference to  FIG. 16 , in the buoyancy-driven kinetic energy generating apparatus of the second embodiment according to the present invention, when the tank  11  has not been filled with a sufficient amount of liquid, the first float  3   p  is located in the float completely exposed section Z 3 , and the roller  331  keeps contacting the maintaining sections  522  of the rails  52  such that the extension magnitude of the first float  3   p  is maximal. At the same time, the second float  3   q  is in the float hidden section Z 1  and has the maximal retraction magnitude. When the tank  11  is filled with a sufficient amount of liquid, the rotor body  21  can create a relatively great pre-buoyancy in the liquid. Furthermore, due to the space in the housing  31  of the first float  3   p , the first float  3   p  in the float completely exposed section Z 3  additionally and locally increases the buoyancy of the rotor body  21  to imbalance the rotor body  21  such that the rotor body  21  starts to rotate. Thus, the guiding member  33  of the first float  3   p  can keep contacting the outer surfaces of the maintaining sections  522  of the rails  52  in the float completely exposed section Z 3  until the guiding member  33  disengages from the terminal ends  52   b  of the rails  52 . 
         [0123]    With reference to  FIG. 18 , after the first float  3   p  disengages from the maintaining sections  522  of the rails  52 , the roller  331  of the guiding member  33  of the second float  3   q  contacts the outer surfaces of the movement control sections  521  of the rails  52  (i.e., the second float  3   q  is aligned with the telescopic movement start line L 2 ′). The rails  52  start to pull the second float  3   q  into the float gradually extending stroke, and the second float  3   q  gradually extends out of the interior of the rotor body  21 . Thus, the first float  3   p  and the second float  3   q  move in the diametrical direction relative to the rotor body  21 , and the first float  3   p  is synchronously moved into the float gradual retracting stroke and gradually retracts into the interior of the rotor body  21 . 
         [0124]    At this time, the extension magnitude of the second float  3   q  increases gradually in the float gradual extending section Z 2 . Thus, the buoyancy of the buoyancy-driven kinetic energy generating apparatus is gradually increased to take over assistance in rotation of the rotor body  21 . Likewise, the first float  3   p  can emerge from the liquid to a position above the level F after passing through the telescopic movement start line L 2 ′. Thus, the first float  3   p  can move synchronously with the second float  3   q  without resistance caused by the liquid, gradually retracting the housing  31  of the first float  3   p  into the interior of the rotor body  21 . 
         [0125]    With reference to  FIG. 19 , when the second float  3   q  is aligned with the maintaining sections  522  of the rails  52  (i.e., the second float  3   q  is aligned with the telescopic movement end line L 1 ′), the second float  3   q  is pulled and has the maximal extension magnitude. Thus, the rotor body  21  is driven to rotate under the maximal buoyancy. At the same time, the first float  3   p  above the level F is actuated to a state having the maximal retraction magnitude, such that the first float  3   p  can reenter the liquid and the float hidden section Z 1  with the minimal resistance. 
         [0126]    While the second float  3   q  is aligned with the maintaining sections  522  of the rails  52 , the rails  52  stop pulling the second float  3   q , and the maintaining sections  522  of the rails  52  keep the second float  3   q  in the state having the maximal extension magnitude until the second float  3   q  disengages from the terminal ends  52   b  of the rails  52  (see  FIG. 20 ). On the other hand, the first float  3   p  reentering the liquid will rotate jointly with the rotor body  21  to a position aligned with the rails  52 , and the guiding member  33  of the first float  3   p  contact the outer surfaces of the movement control sections  521  of the rails  52  such that the first float  3   p  gradually extends out of the interior of the rotor body  21  to its maximal extension magnitude (see  FIG. 16 ), completing a telescopic cycle. 
         [0127]      FIG. 21  shows a buoyancy-driven kinetic energy generating apparatus of a third embodiment according to the present invention. The third embodiment is substantially the same as the second embodiment except that the telescopic movement control module is different in shape and location. Namely, in contrast to the second embodiment in which the first float  3   p  and the second float  3   q  are actuated by pulling, the floats  3   p  and  3   q  in this embodiment are actuated by pressing. 
         [0128]    Specifically, the telescopic movement control module  6  of this embodiment is mounted in the tank  11 . As a non-restrictive example, the telescopic movement control module  6  is in the upper portion of the rotor body  21 . The telescopic movement control module  6  includes a pressing board  61  and a plurality of fasteners  62 . The pressing board  61  is a substantially arcuate board and includes a start end  61   a  and a terminal end  61   b . The extending direction of the pressing board  61  from the start end  61   a  to the terminal end  61   b  is the rotating direction of the rotor  2 , such that each of the first float  3   p  and the second float  3   q  enters the range of the pressing board  61  via the start end  61   a  and leaves the range of the pressing board  61  via the terminal end  61   b . The pressing board  61  includes a movement control section  611  and a maintaining section  612  following the movement control section  611  in the rotating direction of the rotor  2 . A spacing between the movement control section  611  and the rotating center of the rotor  2  decreases from a point of the movement control section  611  toward the maintaining section  612 . The inner surface of the maintaining section  612  is concentric to the peripheral face  21   b  of the rotor body  21 . 
         [0129]    A telescopic movement end line L 1  passes through the connection between the movement control section  611  and the maintaining section  612  and the rotating center of the rotor body  21  and is preferably at an angle of 45° to a horizontal line. A telescopic movement start line L 2 ′ passes through the rotating center of the rotor body  21  and is orthogonal to the telescopic movement end line L 1 ′. The telescopic movement end line L 1 ′ and the telescopic movement start line L 2 ′ divide the space of the tank  11  into four sections (starting from the telescopic movement end line L 1 ′ in the rotating direction of the rotor  2 ): a float hidden section Z 1 , a float gradual extending section Z 2 , a float completely exposed section Z 3 , and a float gradual retracting section Z 4 . The float hidden section Z 1  is opposite to the float completely exposed section Z 3  in a diametric direction of the rotor body  21 . The float gradual extending section Z 2  is opposite to the float gradual retracting section Z 4  in a diametric direction of the rotor body  21 . Each of the first float  3   p  and the second float  3   q  can undergo the float hidden stroke, the float gradual extending stroke, the float completely exposed stroke, and the float gradual retracting stroke. 
         [0130]    By such an arrangement, in operation of the buoyancy-driven kinetic energy generating apparatus of the third embodiment according to the present invention, the first float  3   p  and the second float  3   q  can separately undergo the float hidden stroke, the float gradual extending stroke, the float completely exposed stroke, and the float gradual retracting stroke in the float hidden section Z 1 , the float gradual extending section Z 2 , the float completely exposed section Z 3 , and the float gradual retracting section Z 4  (c.f.  FIG. 7 ), providing alternate assistance in rotation of the rotor body  21  to maintain smooth rotation of the rotor body  21 . 
         [0131]    Based on the structure, when the buoyancy-driven kinetic energy generating apparatus of the third embodiment according to the present invention operates, the first float  3   p  and the second float  3   q  can undergo the float hidden stroke, the float gradual extending stroke, the float completely exposed stroke, and the float gradual retracting stroke in the float hidden section Z 1 , the float gradual extending section Z 2 , the float completely exposed section Z 3 , and the float gradual retracting section Z 4 , respectively. As such, the first float  3   p  and the second float  3   q  can alternately provide assistance in rotation of the rotor body  21 , maintaining smooth rotation of the rotor body  21 . When the roller  331  of the guiding member  33  of the first float  3   p  (or the second float  3   q ) contacts the inner surface of the movement control section  611  of the pressing board  61  (i.e., the roller  331  is aligned with the telescopic movement start line L 2 ′), the pressing board  61  starts to push the first float  3   p  (or the second float  3   q ) into the float gradually retracting stroke, so that the first float  3   p  (or the second float  3   q ) gradually retracts into the interior of the rotor body  21 . In this regard, the second float  3   q  (or the first float  3   p ) enters the float gradually extending stroke, and gradually extends out of the interior of the rotor body  21  under actuation by the connecting module  35 . Thus, the first float  3   p  and the second float  3   q  telescope in the radial directions relative to the rotor body  21 . The gradually increased buoyancy of the second float  3   q  (or the first float  3   p ) alternately assists in rotation of the rotor body  21 . When the roller  331  of the guiding member  33  of the first float  3   p  (or the second float  3   q ) contacts the inner surface of the maintaining section  612  of the pressing board  61  (i.e., the roller  311  is aligned with the telescopic movement end line L 1 ′), the first float  3   p  (or the second float  3   q ) is pressed to the maximal retraction magnitude, and the pressing board  61  stops pressing the first float  3   p  (or the second float  3   q ) such that the first float  3   p  (or the second float  3   q ) undergoes the float hidden stroke. At the same time, the second float  3   q  (or the first float  3   p ) is actuated by the connecting module  35  to the maximal extension magnitude and undergoes the float completely exposed stroke. Thus, the buoyancy-driven kinetic energy generating apparatus of the third embodiment according to the present invention can achieve the same effect of enhancing the kinetic energy generating effect as the first and second embodiments. 
         [0132]      FIGS. 22 and 23  show a buoyancy-driven kinetic energy generating apparatus of a fourth embodiment according to the present invention. The fourth embodiment is substantially the same as the second embodiment except for the number of the floats to further enhance the kinetic energy generating effect. 
         [0133]    Specifically, the buoyancy-driven kinetic energy generating apparatus includes four floats  3  in the embodiment shown in  FIGS. 22 and 23 . The four floats  3  include a first float  3   p , a second float  3   q , a third float  3   r , and a fourth float  3   s . The peripheral face  21   b  further includes a third slot  211   c  and a fourth slot  211   d . As such, the first float  3   p , the second float  3   q , the third float  3   r  and the fourth slot  3   s  are mounted in the first slot  211   a , the second slot  211   b , the third slot  211   c  and the fourth slot  211   d , respectively. The housing  31  of the first float  3   p  and the housing  31  of the second float  3   q  are opposite to each other in a diametric direction of the rotor body  21  and are connected by a connecting module  35 , such that the first float  3   p  and the second float  3   q  synchronously move relative to the rotor body  21  in the corresponding radial direction. Likewise, the housing  31  of the third float  3   r  and the housing  31  of the fourth float  3   s  are opposite to each other in a diametric direction of the rotor body  21  and are connected by another connecting module  35 , such that the third float  3   r  and the fourth float  3   s  synchronously move relative to the rotor body  21  in the corresponding radial direction. Furthermore, the first float  3   p , the second float  3   q , the third float  3   r , and the fourth float  3   s  are preferably mounted to the peripheral face  21   b  of the rotor body  21  and are spaced from each other at regular intervals to further enhance the rotational stability of the rotor body  21 . 
         [0134]    When the buoyancy-driven kinetic energy generating apparatus of the fourth embodiment according to the present invention operates, if the first float  3   p  is in a position shown in  FIG. 22 , the first float  3   p  is in the float completely exposed section Z 3 , and the roller  331  of the guiding member  33  of the first float  3   p  keeps contacting the outer surfaces of the maintaining sections  522  of the rails  52  such that the first float  3   p  has the maximal extension magnitude to provide the maximal buoyancy to drive the rotor body  21  to rotate. The second float  3   q  corresponding to the first float  3   p  is located in the float hidden section Z 1  and maintains the state having the maximal retraction magnitude. Thus, first float  3   p  and the second float  3   q  will not move temporarily in the corresponding radial direction relative to the rotor body  21 . At the same time, the third float  3   r  is in the float gradual extending section Z 2 , and the fourth float  3   s  is in the float gradual retracting section Z 4 . The roller  331  of the guiding member  33  of the third float  3   r  contacts the outer surfaces of the movement control sections  521  of the rails  52 . The rails  52  provide the third float  3   r  with a pulling force to gradually increase the extension magnitude of the third float  3   r  out of the rotor body  21 , gradually increasing the buoyancy to assist in rotation of the rotor body  21 . Furthermore, the third float  3   r  and the fourth float  3   s  move relative to the rotor body  21  in the corresponding radial direction such that the fourth float  3   s  is actuated to gradually retract into the interior of the rotor body  21  in the float hidden section Z 1 . 
         [0135]    With reference to  FIG. 23 , after the roller  331  of the guiding member  33  of the first float  3   p  disengages from the terminal ends  52   b  of the rails  52 , the roller  331  of the guiding member  33  of the corresponding second float  3   q  immediately contacts the outer surfaces of the movement control sections  521  of the rails  52  (i.e., the second float  3   q  is aligned with the telescopic movement start line L 2 ′). Thus, the second float  3   q  is pulled by the rails  52  and undergoes the float gradually extending stroke and gradually extends out of the rotor body  21  to gradually increase the buoyancy assisting in rotation of the rotor body  21 . Furthermore, the first float  3   p  and the second float  3   q  are about to move relative to the rotor body  21  in the corresponding radial direction for synchronously moving the first float  3   p  into the float gradually retracting stroke and gradually retracting the first float  3   p  into the interior of the rotor body  21 . On the other hand, while the second float  3   q  passes through the telescopic movement start line L 2 ′, the third float  3   r  passes through the telescopic movement end line L 1 ′ to undergo the float completely exposed stroke such that the third float  3   r  maintains the maximal extension magnitude in the float completely exposed section Z 3  to drive the rotor body  21  to rotate with the maximal buoyancy. The corresponding fourth float  3   s  undergoes the float hidden stroke and maintains the maximal retraction magnitude in the float hidden section Z 1 . Thus, the third float  3   r  and the fourth float  3   s  do not move temporarily in the corresponding radial direction relative to the rotor body  21 . 
         [0136]    By such an arrangement, in operation of the buoyancy-driven kinetic energy generating apparatus of the fourth embodiment according to the present invention, the first float  3   p , the second float  3   q , the third float  3   r , and the fourth float  3   s  can separately undergo the float hidden stroke, the float gradual extending stroke, the float completely′ exposed stroke, and the float gradual retracting stroke in the float hidden section Z 1 , the float gradual extending section Z 2 , the float completely exposed section Z 3 , and the float gradual retracting section Z 4  (c.f.  FIG. 7 ), providing alternate assistance in rotation of the rotor body  21  to maintain smooth rotation of the rotor body  21 . Compared to the first, second, and third embodiments, the fourth embodiment further enhances the kinetic energy generating efficiency. 
         [0137]      FIG. 24  shows a buoyancy-driven kinetic energy generating apparatus of a fifth embodiment according to the present invention substantially the same as the fourth embodiment. The fifth embodiment is substantially the same as the fourth embodiment except that the telescopic movement control module is different in shape and location. Namely, similar to the third embodiment, the telescopic movement control module of this embodiment actuates the first float  3   p  and the second float  3   q  (or third float  3   r  and the fourth float  3   s ) by pressing. Thus, the buoyancy-driven kinetic energy generating apparatus of the fifth embodiment according to the present invention can also achieve the same effect of the fourth embodiment in enhancing the kinetic energy generating efficiency. The operational principles of the buoyancy-driven kinetic energy generating apparatus of the fifth embodiment are substantially the same as those mentioned above and are not set forth again to avoid redundancy. 
         [0138]      FIG. 25  is a schematic diagram illustrating the extension magnitude of the float  3  when the rotor  2  according to the present invention rotates in a counterclockwise direction. The hatching area in  FIG. 25  indicates the extension magnitude of the float  3  in the tank  11 . Namely, the rotor body  21  can also rotate in the tank  11  in the counterclockwise direction. When the buoyancy-driven kinetic energy generating apparatus operates, the float  3  completes a telescopic cycle relative to the peripheral face  21   b  of the rotor body  21  while the float  3  rotates a round together with the rotor body  21 . Each telescopic cycle includes four strokes: a float hidden stroke, a float gradual extending stroke, a float completely exposed stroke, and a float gradual retracting stroke. The float  3  maintains its maximal retraction magnitude (i.e., the extension magnitude is minimal) during the float hidden stroke. The extension magnitude of the float  3  increases gradually during the float gradual extending stroke. The float  3  maintains its maximal extension magnitude during the float completely exposed stroke. The extension magnitude of the float  3  decreases gradually during the float gradual retracting stroke, and the float  3  has the maximal retraction magnitude when the float  3  returns to the float hidden stroke. 
         [0139]    The number of the floats  3  ranges from 1 to 4 in the embodiments shown. However, the number of the floats  3  can be larger than four and can be adjusted and modified according to needs, which can be appreciated by one having ordinary skill in the art. The present invention is not restricted by the embodiments shown. Furthermore, when the number of the floats  3  is more than one, the floats  3  do not have to be spaced from each other at regular intervals. The spacing between two adjacent floats  3  can be adjusted to control the speed change of the rotor  2 . Furthermore, the floats  3  of the buoyancy-driven kinetic energy generating apparatus according to the present invention can telescope on the opposite end faces  21   a  of the rotor body  21 . In another example, the float  3  in the extended state can be flush with the outer surface of the rotor body  21  (the end faces  21   a  or the peripheral face  21   b ), and the float  3  in the retracted state can be in a recess in the outer surface of the rotor body  21 , which also can imbalance the rotor body  21  and cause rotation of the rotor body  21 . 
         [0140]      FIG. 26  shows a buoyancy-driven kinetic energy generating apparatus of a sixth embodiment according to the present invention substantially the same as the fourth embodiment. The buoyancy-driven kinetic energy generating apparatus in this embodiment also includes four floats  3  (i.e. the first float  3   p , the second float  3   q , the third float  3   r  and the fourth float  3   s ). When the four floats  3  enter the float gradual extending section Z 2  in turn during the rotation, the extension magnitude of each float  3  increases gradually. In the embodiment, the connecting module  35  is also used to provide synchronous movement between the first float  3   p  and the second float  3   q  and between the third float  3   r  and the fourth float  3   s . The main differences between the sixth embodiment and the fourth embodiment are the rotating direction of the rotor body  21  (the rotor body  21  rotates in the counterclockwise direction in the embodiment) and the structure of the telescopic movement control module  7  that is used to control the telescopic movement of the floats  3 . 
         [0141]    Specifically, referring to  FIGS. 26 and 27 , the telescopic movement control module  7  includes a guiding track  71  and a plurality of slidewheel units  72 . The plurality of slidewheel units  72  has the same quantity as the floats  3 . In the embodiment, since four floats  3  are used, therefore four slidewheel units  72  are included. The four slidewheel units  72  are mounted to the rotor body  21  and respectively connected to the four floats  3 . The guiding track  71  is mounted in the tank  11 . The guiding track  71  guides the four slidewheel units  72  to move, thereby controlling the telescopic movement of a corresponding float  3 . 
         [0142]    In the embodiment, the telescopic movement control module  7  further includes a bracket  73 . The bracket  73  is mounted to the inner wall of the tank  11 , and the guiding track  71  is mounted to the bracket  73 . As such, the guiding track  71  faces a part of the peripheral face  21   b  of the rotor body  21 . In a preferred and non-limiting case, the guiding track  71  is arranged to face substantially the lower portion of the peripheral face  21   b.    
         [0143]    The guiding track  71  includes a start end  71   a  and a terminal end  71   b . The guiding track  71  extends from the start end  71   a  to the terminal end  71   b  in a direction substantially the same as the rotating direction of the rotor body  21 . Each float  3  enters the guiding track  71  at the start end  71   a  and departs from the guiding track  71  at the terminal end  71   b . The guiding track  71  includes an abutment face  711  facing the peripheral face  21   b  of the rotor body  21  and is substantially in an arcuate form. The guiding track  71  may include a movement control section  712  and a maintaining section  713  connected to the movement control section  712 . In the movement control section  712 , a spacing between the abutment face  711  and the rotating center of the rotor  2  decreases from the start end  71   a  towards a connection end of the movement control section  712  connected to the maintaining section  713 . In the maintaining section  713 , the abutment face  711  and the peripheral face  21   b  of the rotor body  21  may be concentric. 
         [0144]    A telescopic movement end line L 1 ″ is at an angle of 45° to a horizontal line, and passes through the rotating center of the rotor body  21  and the movement control section  712  of the guiding track  71 . A telescopic movement start line L 2 ″ passes through the rotating center of the rotor body  21  and the maintaining section  713  of the guiding track  71 , and is orthogonal to the telescopic movement end line L 1 ″. The telescopic movement end line L 1 ″ and the telescopic movement start line L 2 ″ divide the space of the tank  11  into four sections (starting from the telescopic movement end line L 1 ″ in the rotating direction of the rotor  2 ): a float hidden section Z 1 , a float gradual extending section Z 2 , a float completely exposed section Z 3 , and a float gradual retracting section Z 4 . The float hidden section Z 1  is opposite to the float completely exposed section Z 3  in a diametric direction of the rotor body  21 . The float gradual extending section Z 2  is opposite to the float gradual retracting section Z 4  in a diametric direction of the rotor body  21 . Each of the floats  3  can undergo the float hidden stroke, the float gradual extending stroke, the float completely exposed stroke, and the float gradual retracting stroke. 
         [0145]    Each slidewheel unit  72  includes a first slidewheel unit  721  mounted to the outer surface of the housing  31 . Preferably, the first slidewheel unit  721  may be mounted to the center of the outer surface of the housing  31 . 
         [0146]    Each slidewheel unit  72  further includes a positioning unit  722  and a pivoting unit  723 . Both the positioning unit  722  and the pivoting unit  723  are directly or indirectly connected to the rotor body  21  in order to synchronously rotate with the rotor body  21 . In the embodiment, the positioning unit  722  is more adjacent to the liquid breaking portion  311  than the pivoting unit  723  is to the liquid breaking portion  311 . The positioning unit  722  includes a positioning support  7221  having two ends respectively fixed to two opposing outer tracks  23  of the rotor  2 . In this arrangement, the positioning support  7221  can stretch over the peripheral face  21   b  of the rotor body  21 . The positioning support  7221  can also connect to the free ends of the two outer tracks  23  to prevent the positioning support  7221  from hindering the telescopic movement of the float  3 . 
         [0147]    The positioning unit  722  further includes a second slidewheel unit  7222  mounted to the positioning support  7221 . The second slidewheel unit  7222  has an axis that may be parallel to an axis of the first slidewheel unit  721 . A connecting rope R (such as a steel rope) has an end fixed to the housing  31  or the positioning support  7221  and wound around the first slidewheel unit  721  and the second slidewheel unit  7222 . In this arrangement, the first slidewheel unit  721  forms a “moving slidewheel” with respect to the positioning unit  722 . 
         [0148]    The pivoting unit  723  includes a pivoting frame  7231  pivotally connected to the peripheral face  21   b  of the rotor body  21 . The pivoting frame  7231  pivots about an axis that may be parallel to the axis of the first slidewheel unit  721 . The connecting rope R has another end that may be fixed to the pivoting frame  7231 . The connecting rope R is preferably nonelastic to maintain the connecting rope R in a constant length. The first slidewheel unit  721 , the second slidewheel unit  7222  and two end of the connecting rope R can be located on the same plane, permitting the connecting rope R to connect between the first slidewheel unit  721  and the second slidewheel unit  7222  in a 2-D manner. Thus, generation of the branch force during the synchronous movement can be reduced. Particularly, the connecting rope R may distribute along a plane orthogonal to the axis of the first slidewheel unit  721 , attaining improved dragging effect of the connecting rope R. 
         [0149]    The pivoting unit  723  further includes a rocking arm  7232  and a rolling member  7233 . The rocking arm  7232  is fixed to the pivoting frame  7231 . The rocking arm  7232  may extend in a direction parallel to the end face  21   a  of the rotor body  21 . The length of the rocking arm  7232  is preferably adjustable. The rolling member  7233  is rotatably mounted to the rocking arm  7232  (preferably mounted to the free end of the rocking arm  7232 ). Therefore, when the rolling member  7233  keeps in contact with the guiding track  71 , the rolling member  7233  can smoothly move along the abutment face  711  of the guiding track  71 , driving the rocking arm  7232  and the pivoting frame  7231  to pivot synchronously. 
         [0150]    Besides, each slidewheel unit  72  may include an auxiliary positioning unit  724  which is also directly or indirectly connected to the rotor body  21  to rotate synchronously with the rotor body  21 . The auxiliary positioning unit  724  is also positioned between the positioning unit  722  and the pivoting unit  723 . In the embodiment, the auxiliary positioning unit  724  includes an auxiliary positioning support  7241  having two ends respectively fixed to another two opposing outer tracks  23  of the rotor  2 . In this arrangement, the auxiliary positioning support  7241  can also stretch over the peripheral face  21   b  of the rotor body  21 . Also, the auxiliary positioning support  7241  can connect to the free ends of said the other two outer tracks  23  to prevent the auxiliary positioning support  7241  from hindering the telescopic movement of the float  3 . Moreover, the auxiliary positioning unit  724  includes a rotatable tension wheel  7242  whose axis may be parallel to the axis of the first slidewheel unit  721 . The connecting rope R is wound around the first slidewheel unit  721 , the second slidewheel unit  7222  and the tension wheel  7242 , and is finally fixed to the pivoting frame  7231 . The arrangement of the pivoting frame  7231  can maintain the connecting rope R in a tensed state to prevent the connecting rope R from hindering the float  3  when the float  3  is extending. 
         [0151]    Referring to  FIG. 28 , in another embodiment, if it can be ensured that the float  3  is not hindered by the connecting rope R when the float  3  is extending, the auxiliary positioning unit  724  (shown in  FIG. 27 ) can be omitted to simplify the structural complexity of the buoyancy-driven kinetic energy generating apparatus. 
         [0152]    Referring to  FIGS. 29 and 30 , during the rotation of the rotor body  21 , when the rocking arm  7232  of the pivoting unit  723  of a corresponding float  3  makes contact with the guiding track  71  at the start end  71   a , the rocking arm  7232  can drive the pivoting frame  7231  to rotate. As a result, the rolling member  7233  abuts with and rolls upon the abutment face  711  of the guiding track  71 . As the rotor body  21  continues to rotate, when the rolling member  7233  is in the movement control section  712 , the dragged rocking arm  7232  can constantly pivot the pivoting frame  7231  relative to the rotor body  21 . Thus, the connecting rope R can be pulled (see the change from  FIG. 29  to  FIG. 30 ) to gradually increase the length of the connecting rope R between the positioning unit  722  and the pivoting unit  723 . This gradually reduces the length of the connecting rope R between the positioning unit  722  and the first slidewheel unit  721 . As a result, the float  3  (such as float  3   p ) can be gradually pulled outwards while the opposing float  3  (such as float  3   q ) is gradually retracted to the rotor body  21  at the same time. 
         [0153]    Referring to  FIG. 31 , when the rolling member  7233  reaches the maintaining section  713  of the guiding track  71 , the dragged rocking arm  7232  can stop pivoting the pivoting frame  7231 . Thus, pulling of the connecting rope R is stopped. As such, the float  3  can remain in a state having the maximal extension magnitude without the telescopic movement relative to the rotor body  21 . 
         [0154]    Referring to  FIGS. 26 and 30 , it is noted that since the first slidewheel unit  721  forms a “moving slidewheel” with respect to the positioning unit  722 , the connecting rope R requires significantly less effort to pull the float  3 . In addition, since the rocking arm  7232  of the pivoting unit  723  can provide the pulling force with a larger arm of force, the connecting rope R requires even a less effort to pull the float  3 . Thus, the buoyancy-driven kinetic energy generating apparatus in the embodiment consumes less energy during the operation, providing a smooth operation of the buoyancy-driven kinetic energy generating apparatus and enhancing the efficiency in generating the kinetic energy. 
         [0155]    Furthermore, consider that the connecting rope R pulls the first slidewheel unit  721  with a force. In this regard, only the radial component of the force in the radial direction of the rotor body  21  is effective in pulling the float  3 . Therefore, in this embodiment, the second slidewheel unit  7222  of the positioning unit  722  is arranged to be diametrically opposing to the first slidewheel unit  721 , such that a majority of the pulling force of the connecting rope R can be effective in pulling the float  3 . Thus, smooth pulling operation of the float  3  can be attained. 
         [0156]    Although the buoyancy-driven kinetic energy generating apparatus of the sixth embodiment according to the present invention is designed with the structure for counterclockwise rotation, a mirror structure of the illustrated structure can be used for clockwise rotation of the buoyancy-driven kinetic energy generating apparatus, as it can be readily appreciated by the skilled person in the art. Also, the structure of the buoyancy-driven kinetic energy generating apparatus can be modified according to the user&#39;s requirement, and therefore is not limited to the drawing. 
         [0157]      FIG. 32  shows a buoyancy-driven kinetic energy generating apparatus of a seventh embodiment according to the present invention. Similar to the sixth embodiment, the buoyancy-driven kinetic energy generating apparatus in this embodiment also uses a telescopic movement control module  8  which drives the floats  3  to move telescopically via a plurality of slidewheel units. 
         [0158]    Specifically, referring to  FIGS. 32 and 33 , the telescopic movement control module  8  includes a guiding track  81  and a plurality of slidewheel units  82 . The plurality of slidewheel units  82  has the same quantity as the floats  3 . In the embodiment, since four floats  3  are used, therefore four slidewheel units  82  are included. The four slidewheel units  82  are mounted to the rotor body  21  and connected to the four floats  3 , respectively. The guiding track  81  is mounted in the tank  11 . The guiding track  81  actuates the four slidewheel units  82  to control the telescopic movement of the floats  3 . 
         [0159]    In the embodiment, the guiding track  81  can be mounted to the support  111  of the tank  11  (see  FIG. 2 ) such that the guiding track  81  faces a part of the peripheral face  21   b  of the rotor body  21 . In another option, similar to the sixth embodiment, the tank  11  may receive a bracket mounted to the guiding track  81 . The invention is not limited to either option. 
         [0160]    The guiding track  81  includes a start end  81   a  and a terminal end  81   b . The guiding track  81  extends from the start end  81   a  to the terminal end  81   b  in a direction substantially the same as the rotating direction of the rotor body  21 . Each float  3  can enter the guiding track  81  at the start end  81   a  and depart from the guiding track  81  at the terminal end  81   b . The guiding track  81  includes an abutment face  811  facing the peripheral face  21   b  of the rotor body  21  and is substantially in an arcuate form. The guiding track  81  may include a movement control section  812  and a maintaining section  813  connected to the movement control section  812 . In the movement control section  812 , a spacing between the abutment face  811  and the rotating center of the rotor  2  decreases from the start end  81   a  towards a connection end of the movement control section  812  connected to the maintaining section  813 . In the maintaining section  813 , the abutment face  811  and the peripheral face  21   b  of the rotor body  21  may be concentric. 
         [0161]    A telescopic movement end line L 3  is at an angle of 45° to a horizontal line, and passes through the rotating center of the rotor body  21  and the maintaining section  813  of the guiding track  81 . A telescopic movement start line L 4  passes through the rotating center of the rotor body  21  and the maintaining section  813  of the guiding track  81 . The telescopic movement start line L 4  may be a vertical line V orthogonal to the horizontal line. Alternatively, the telescopic movement start line L 4  may be at an angle of less than 10° to the vertical line V. Thus, each float  3  passes through the vertical line V and the telescopic movement start line L 4  in sequence according to the rotating direction. The telescopic movement end line L 3  and the telescopic movement start line L 4  divide the space of the tank  11  into four sections (starting from the telescopic movement end line L 3  in the rotating direction of the rotor  2 ): a float hidden section Z 1 , a float gradual extending section Z 2 , a float completely exposed section Z 3 , and a float gradual retracting section Z 4 . The float hidden section Z 1  is opposite to the float completely exposed section Z 3  in a diametric direction of the rotor body  21 . The float gradual extending section Z 2  is opposite to the float gradual retracting section Z 4  in a diametric direction of the rotor body  21 . Each of the floats  3  can undergo the float hidden stroke, the float gradual extending stroke, the float completely exposed stroke, and the float gradual retracting stroke. 
         [0162]    Each slidewheel unit  82  includes a first slidewheel unit  821  mounted to the outer surface of the housing  31 . Preferably, the first slidewheel unit  821  may be mounted to the center of the outer surface of the housing  31 . 
         [0163]    Each slidewheel unit  82  includes a first slidewheel unit  821  mounted to the outer face of the housing  31  of a corresponding float  3 . The first slidewheel unit  821  is preferably mounted to the center of the outer face of the housing  31 . 
         [0164]    Each slidewheel unit  82  further includes a positioning unit  822  and a pivoting unit  823 . Both the positioning unit  822  and the pivoting unit  823  are directly or indirectly connected to the rotor body  21  for synchronous rotation with the rotor body  21 . In the embodiment, the positioning unit  822  is more adjacent to the liquid breaking portion  311  than the pivoting unit  823  is to the liquid breaking portion  311 . The positioning unit  822  includes a positioning support  8221  and a second slidewheel unit  8222 . The positioning support  8221  includes two ends respectively fixed to two opposing outer tracks  23  of the rotor  2 . In this arrangement, the positioning support  8221  can stretch over the peripheral face  21   b  of the rotor body  21 . The positioning support  8221  can also connect to the free ends of the two outer tracks  23  to prevent the positioning support  8221  from hindering the telescopic movement of the float  3 . 
         [0165]    The second slidewheel unit  8222  is mounted to the positioning support  8221 . The second slidewheel unit  8222  has an axis that may be parallel to an axis of the first slidewheel unit  821 . The second slidewheel unit  8222  may be opposing to the first slidewheel unit  821  in a radial direction of the rotor body  21 . A connecting rope R (such as a steel rope) has an end fixed to the housing  31  or the positioning support  8221  and wound through the first slidewheel unit  821  and the second slidewheel unit  8222 . In this arrangement, the first slidewheel unit  821  forms a “moving slidewheel” with respect to the positioning unit  822 . The connecting rope R is preferably nonelastic to maintain the connecting rope R in a constant length. Furthermore, in the embodiment, the first slidewheel unit  821  or the second slidewheel unit  8222  can include two or more slidewheels to enhance the mechanical performance of the slidewheel units  82 . 
         [0166]    The positioning unit  822  may further include a third slidewheel unit  8223 . The third slidewheel unit  8223  may be mounted to the outer track  23  or the ring  24  of the rotor  2 . In this regard, the connecting rope R can be wound around the third slidewheel unit  8223  and then diverted to the lateral side of the float  3 . 
         [0167]    The pivoting unit  823  includes a rocking arm  8231 , a fourth slidewheel unit  8232  and a rolling member  8233 . The rocking arm  8231  is pivotally connected to the peripheral face  21   b  of the rotor body  21 . The rocking arm  8231  pivots about an axis that may be parallel to the axis of the rotor body  21 . The rocking arm  8231  may extend in a direction parallel to the end face  21   a  of the rotor body  21 . The fourth slidewheel unit  8232  and the rolling member  8233  are mounted to the rocking arm  8231 . After the connecting rope R passes through the third slidewheel unit  8223 , the connecting rope R can be wound around the fourth slidewheel unit  8232 , and one end of the connecting rope R can be fixed to the ring  24 . The rolling member  8233  is rotatably mounted to the rocking arm  8231  (preferably to the free end of the rocking arm  8231 ). Therefore, when the rolling member  8233  keeps in contact with the guiding track  81 , the rolling member  8233  can smoothly move along the abutment face  811  of the guiding track  81 , driving the rocking arm  8231  to pivot. 
         [0168]    Referring to  FIG. 34 , during the rotation of the rotor body  21 , the float  3  that undergoes the float hidden stroke can maintain in a state having the maximal retraction magnitude (i.e., the extension magnitude is minimal) before the rocking arm  8231  of the corresponding pivoting unit  823  makes contact with the start end  81   a  of the guiding track  81 . 
         [0169]    Referring to  FIGS. 35 and 36 , as the rotor body  21  continues to rotate, the rocking arm  8231  can be pushed by the guiding track  81  to pivot when the rocking arm  8231  makes contact with the start end  81   a  of the guiding track  81 . At this time, the fourth slidewheel unit  8232  pulls the connecting rope R to gradually increase the length of the connecting rope R between the positioning unit  822  and the pivoting unit  823 . This gradually reduces the length of the connecting rope R between the positioning unit  822  and the first slidewheel unit  821 . As a result, the float  3  can be gradually pulled outwards (the float gradually extending stroke) while the opposing float  3  is gradually retracted to the rotor body  21  (the float gradual retracting stroke). When the pivoting angle of the rocking arm  8231  is larger than a predetermined angle, the rolling member  8233  of the pivoting unit  823  can enter the movement control section  812  of the guiding track  81 , and roll upon the abutment face  811  of the guiding track  81 . As such, the rocking arm  8231  can continue to pivot, thereby continuously pulling the float  3  outwards. 
         [0170]    Referring to  FIG. 37 , as the rotor body  21  continues to rotate, the float  3  can remain in a state having a maximal extension magnitude (the float completely exposed stroke) when the rolling member  8233  moves from the movement control section  812  to the maintaining section  813 . At this time, the rocking arm  8231  stops pivoting, and pulling of the connecting rope R is stopped. The float  3  can remain in the state having the maximal extension magnitude without the telescopic movement. 
         [0171]      FIG. 38  is a schematic diagram illustrating the extension magnitude of the float  3  when the rotor  2  according to a seventh embodiment of present invention rotates in a counterclockwise direction. The hatching area in  FIG. 38  indicates the extension magnitude of the float  3  in the tank  11 . 
         [0172]    Since the telescopic movement start line L 4  is used as the vertical line V (or the telescopic movement start line L 4  is at an angle of less than 10° to the vertical line V) in this embodiment, it can be ensured that the float gradual extending section Z 2  is located between the vertical line V and the horizontal line, with the vertical line V passing through the rotating center of the rotor body  21 . This ensures that the float  3  extends out of the interior of the rotor body  21  only after passing through the vertical line V. Thus, the buoyancy energy generated by the float  3  can assist the rotation of the rotor  2 , providing smooth rotation of the rotor  2 . 
         [0173]    Furthermore, at the upper portion of the rotor body  21 , the telescopic movement end line L 3  passes through a location (point C in  FIG. 38 ) which defines a maximal level F 1 . The horizontal line passing through the rotating center of the rotor body  21  defines a minimal level F 2 . If the liquid in the tank  11  exceeds the maximal level F 1 , the float  3  cannot fully retract into the interior of the rotor body  21  before the float  3  sinks into the liquid. As a disadvantage, the float  3  encounters a larger resistance when sinking into the liquid, lowering the smoothness in the rotation of the rotor  2 . Likewise, if the liquid in the tank  11  is lower than the minimal level F 2 , the period of time for which the float  3  undergoes the float completely exposed stroke will be too short. Therefore, there is insufficient power to assist in the rotation of the rotor  2 , which also lowers the smoothness in the rotation of the rotor  2 . Thus, the liquid level in the tank  11  is preferably between the maximal level F 1  and the minimal level F 2 . 
         [0174]    Note that when the guiding tracks  71  and  81  in the sixth and seventh embodiments are designed in a circular form, the guiding tracks  71  and  81  can also guide the floats  3  to move telescopically as it is the case of the first embodiment. Therefore, there can be only one float  3 . Synchronous movement mechanism is not required between the floats  3 . In addition, the float hidden stroke, the float gradual extending stroke, the float completely exposed stroke, and the float gradual retracting stroke can be controlled by the guiding tracks  71  and  81 , so that the float hidden section Z 1 , the float gradual extending section Z 2 , the float completely exposed section Z 3 , and the float gradual retracting section Z 4  may have different ranges. In other words, the float hidden section Z 1  does not necessarily have to be opposing to the float completely exposed section Z 3  in a diametric direction of the rotor body  21 , and the float gradual extending section Z 2  does not necessarily have to be opposing to the float gradual retracting section Z 4  in a diametric direction of the rotor body  21 . 
         [0175]    Besides, the buoyancy-driven kinetic energy generating apparatus according to the present invention may further include a speed regulator (such as a constant speed motor) connected to the shaft portion  22  of the rotor  2 . The speed regulator maintains the rotor body  21  of the rotor  2  in a constant rotating speed, such that the buoyancy-driven kinetic energy generating apparatus can stably generate the kinetic energy. In a case where the tank  11  is filled with a sufficient amount of liquid and the rotor body  21  keeps rotating under imbalance, the speed regulator consumes less energy. The energy of the speed regulator can be provided by a generator connected to the shaft portion  22 . In addition, the speed regulator consumes more energy to assist the rotor body  21  in achieving or restoring an expected rotating speed only when the rotation of the rotor body  21  is not yet stable or when the buoyancy-driven kinetic energy generating apparatus is suddenly added with an extra load during the generation of the kinetic energy. Therefore, the speed regulator can further include a switching unit, such that the speed regulator can be switched to mains electricity or other power supply to obtain the required power when a larger amount of energy consumption takes place. 
         [0176]    In view of the foregoing, in the buoyancy-driven kinetic energy generating apparatus according to the present invention, a rotor body  21  containing a mass is received in a tank  11  containing a liquid having a density larger than that of the mass (or a rotor body  21  having a density smaller than that of the liquid is received in the tank  11 ), such that a great pre-buoyancy is exerted to the rotor body  21  due to the density difference and the gravitational force, greatly increasing the total buoyancy. Furthermore, local buoyancy on the rotor body  21  is changed by controlling the float  3  to telescope relative to the rotor body  21 , causing imbalance of the rotor body  21  and, hence, causing rotation of the rotor body  21 . Thus, the input kinetic energy required to maintain the rotation of the rotor body  21  can effectively be reduced, effectively reducing the costs for generating kinetic energy. Furthermore, by cooperation of the inertia generated by the rotor body  21  of a large volume and the arcuate telescopic path of the float  3  rotating jointly with the rotor body  21 , the rotational resistance of the rotor body  21  is reduced, such that the buoyancy-driven kinetic energy generating apparatus can operate smoothly to stably and continuously generate kinetic energy, enhancing the kinetic energy generating efficiency. 
         [0177]    The buoyancy-driven kinetic energy generating apparatus according to the present invention has a simple structure, such that the costs of manufacturing, assembly and maintenance can be reduced.