BACKGROUND ART As representative methods for generating electricity necessary to a human life, thermoelectric power generation uses fossil fuels, nuclear power generation uses a radioactive isotope, and hydroelectric power generation uses flowing water as an energy source, respectively. In addition, there are wind power generation, tidal power generation, solar power generation, and the like.

An illustrative electric generating apparatus using a fluid flow like wind or water is disclosed in U. S.

Patent No. 6,153,944 (Clark, issued on November 28,2000), and another illustrative apparatus using solar energy is disclosed in U. S. Patent No. 5,005,360' (McMurtry, issued on April 9,1991).

However, the facilities for the thermoelectric power generation and the nuclear power generation have complex structures, cost a great amount in generating the electricity due to a large amount of power consumption,

and affect an ecosystem. The hydroelectric power generation is unable to generate sufficient electricity because of limited water sources. Also, the power generation capacity using wind or solar energy is considerably influenced by change of weather.

DISCLOSURE OF INVENTION It is an object of the present invention to provide an electricity generating apparatus using gravity and buoyancy which can curtail costs of power generation and prevent environmental pollution and destruction of an ecosystem.

In order to achieve the above object, the present invention provides an electricity generating apparatus using gravity and buoyancy comprising a case; a water tub which is located in the case and contains water thereinside; a plurality of buoyant bodies which are stored in the water tub and subject to floating on the water by buoyancy ; a drop guiding device which is mounted laterally apart from the water tub at a predetermined distance while being aligned with the tub, the drop guiding device loading the buoyant bodies discharged from the tub and guiding the drop of the buoyant bodies due to their own weights; an entering device which is disposed under the drop guiding device, the entering device interlocking with the drop guiding device to push the buoyant bodies dropped separately from the drop guiding device into the water tub ; and a generator which interlocks with the drop guiding device to generate electricity.

The drop guiding device includes a first driving shaft the both ends of which are rotatably mounted to an inner surface of the case, a second driving shaft which is disposed directly below the first shaft at a predetermined distance and the both ends of which are rotatably mounted to the inner surface of the case, and a conveyor, the both ends of which are caught by the first and second shafts and which has a plurality of supporting bars protrudingly fixed on a surface of the conveyor for loading the buoyant bodies thereon.

One surface of the conveyor is moved downward by the weights of the buoyant bodies which are disposed on the supporting bars, and the opposite surface is moved upward.

The first and second driving shafts rotate by the movement of the conveyor.

A plurality of coupling protrusions are formed radially on the first and second driving shafts, and the conveyor is formed with a plurality of slots in a longitudinal direction, through which the protrusions of the shafts are inserted respectively.

The water tub is formed in a substantially hexahedral shape, a length of the tub being slightly larger than the length of the buoyant body, and a width of the tub being smaller than the length of the body, to thereby maintain the bodies to be disposed parallel in a longitudinal direction without swinging in the tub.

Preferably, the buoyant body is formed in an empty cylindrical shape of a stainless material.

A water supply pipe for supplying the water into the water tub is mounted to an upper side wall of the tub. A water discharging pipe is mounted to a lower side wall of the tub. The upper portion of the water supply pipe-

mounted side wall of the water tub slants outwardly to form an enlarged portion having a relatively larger sectional area. A floater which is cooperatively connected to the water supply pipe is provided on the water in the enlarged portion so as to control the water supply pipe for maintaining the water level uniformly.

Between the drop guiding device and the water tub is mounted a lifting means which picks up the buoyant bodies floating on the water by the buoyancy and feeds the bodies toward the drop guiding device.

The lifting means includes a driven shaft, both ends of which are rotatably mounted to the side walls of the water tub and which interlocks with the first driving shaft, and a plurality of lifters which are protrudingly fixed on a surface of the driven shaft for picking up the buoyant bodies one by one.

The driven shaft of the lifting means is located higher than the first driving shaft of the drop guiding device. Between the lifting means and the drop guiding means is provided a feeding plate which slants down from the lifting means to the drop guiding device so that the buoyant bodies picked up by the lifters move toward the drop guiding device.

The second driving shaft of the drop guiding device is connected to the generator and the entering device, the generator generating electricity by the rotational force of the second driving shaft. The entering device includes a decelerator which receives the rotational force of the second driving shaft and decelerates it to a desired velocity, a motion converting means which is mounted to a shaft of the decelerator to convert the rotating motion of the shaft into the rectilinear motion,

and a piston which is coupled to the motion converting means and performs a rectilinear reciprocating motion.

The motion converting means includes a circular rotating plate, the center of which is fixed to the shaft of the decelerator, a protrusion which is formed on a border of the rotating plate, a link which is coupled to the protrusion at its end, and a hinge piece, one end of which is hingedly coupled to the link and the other end of which is hingedly coupled to the front end of a shaft of the piston.

A put-in pipe, which contains the piston therein and guides the rectilinear movement of the piston, is formed integrally at the lower portion of the front wall of the water tub so that the buoyant bodies dropped separately from the drop guiding device enter the put-in pipe and are put into the water tub by the rectilinear reciprocating movement of the piston. The put-in pipe is located lower than the second driving shaft of the drop guiding device and has a predetermined length such that the pipe is extended outward and inward from the front wall of the water tub. On the outer circumferential surface of the outwardly extended put-in pipe is formed a cut portion through which the buoyant bodies separated from the drop guiding device enter the put-in pipe. And, around the inner circumferential surface of the inwardly extended put-in pipe are provided a plurality of 0-rings.

Between the second driving shaft and the put-in pipe is mounted a sliding plate along which the buoyant bodies roll toward the cut portion of the put-in pipe. The sliding plate slants downward while deviating at a predetermined angle, so as to move the buoyant bodies toward the put-in pipe disposed in front of the front

wall of the water tub from the drop guiding device disposed laterally apart from the water tub.

A braking device for stopping the rotating motion of the second driving shaft of the drop guiding device is mounted on the outer circumferential surface of the second shaft.

BRIEF DESCRIPTION OF DRAWINGS This invention will be better understood and its various objects and advantages will be more fully appreciated from the following description taken in conjunction with the accompanying drawings, in which: FIG. 1 is a perspective view of an electricity generating apparatus using gravity and buoyancy according to the present invention ; and FIG. 2 is a front view of an electricity generating apparatus using gravity and buoyancy according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, this invention will be described in detail with reference to the drawings.

FIGs. 1 and 2 are a perspective view and a front view of an electricity generating apparatus using gravity and buoyancy according to the present invention, respectively.

As shown in the drawings, an electricity generating apparatus 10 using gravity and buoyancy of the present invention comprises a case 11 forming an outer appearance, a water tub 20 which is located in the case 11 and

contains water 20a thereinside, a plurality of buoyant bodies 12 which are stored in the water tub 20 and subject to floating on the water due to the buoyancy, a drop guiding device 30 which loads the buoyant bodies 12 discharged from the tub 20 and guides the drop of the bodies 12 due to their own weights, and an entering device 40 which is disposed under the guiding device 30 and pushes the bodies 12 dropped separately from the device 30 into the tub 20.

Describing more in detail, each buoyant body 12 is preferably formed in an empty cylindrical shape and made from a stainless material, so as to easily float on the water by the buoyancy and not to rust.

The water tub 20 containing the water and the buoyant bodies 12 therein is formed in a substantially hexahedral shape having a predetermined width (w), length (1) and height (h). The length (1) of the tub 20 is slightly larger than the length (d) of the buoyant body 12, and the width (w) is smaller than the length (d) of the body 12, to thereby enable the bodies 12 to be disposed parallel in a longitudinal direction without swinging in the tub 20, as shown in FIGs. 1 and 2.

A water supply pipe 21 for supplying the water into the tub 20 is mounted to an upper side wall of the tub 20 (FIG. 2 is defined as a front view of the inventive apparatus), and a water discharging pipe 22 is mounted to a lower side wall thereof. The upper portion of the water supply pipe-mounted side wall of the water tub 20 slants outwardly to form an enlarged portion 24 having a relatively larger sectional area. A floater 23 which is cooperatively connected to the water supply pipe 21 is provided on the water 20a in the enlarged portion 24. The

floater 23 controls the water supply pipe 21 to maintain the water level uniformly. For this, a partition wall 25 for defining the enlarged portion 24 is mounted in the water tub 20. A plurality of holes 25a are perforated at the partition wall 25, through which the water flows in the enlarged portion 24. The floater 23 may be implemented as a floater which is well known to those skilled in the art.

The drop guiding device 30 is mounted laterally apart from the water tub 20 at a predetermined distance while being aligned with the tub 20. The device 30 comprises a first driving shaft 31, a second driving shaft 32 which is disposed directly below the first shaft 31 at a predetermined distance, and a conveyor 33 which is operated by the first and second shafts 31 and 32. The both ends of the respective first and second shafts 31 and 32 are rotatably mounted to the inner surfaces of the front and rear walls of the case 11 by means of a rotation supporting means like a bearing, etc. The conveyor 33, the both ends of which are caught by the shafts 31 and 32, moves continually downward and upward, as shown in the directions of arrows A and B in Fig. 2.

A plurality of supporting bars 34 for loading the buoyant bodies 12 thereon are protrudingly fixed on a surface of the conveyor 33 while being perpendicular thereto. Two supporting bars 34, which are disposed laterally in alignment with each other, are paired to support one buoyant body 12. The respective paired supporting bars 34 are spaced vertically apart from others at a regular distance. A plurality of coupling protrusions 31a and 32a are formed radially on the first and second driving shafts 31 and 32, respectively. The

conveyor 33 is formed with a plurality of slots 33a in a longitudinal direction, through which the protrusions 31a and 32a of the shafts 31 and 32 are inserted respectively.

That is, the protrusions 31a and 32a of the driving shafts 31 and 32 are inserted in the slots 33a of the conveyor 33 one by one, so the shafts 31 and 32 are accurately engaged with the conveyor 33.

Between the drop guiding device 30 and the water tub 20 is mounted a lifting means which picks up the buoyant bodies 12 floating on the water by the buoyancy and feeds them toward the drop guiding device 30. The lifting means includes a driven shaft 51, both ends of which are rotatably mounted to the front and rear walls of the tub 20, and a plurality of lifters 52 which are protrudingly fixed on a surface of the driven shaft 51 while being perpendicular thereto for loading the buoyant bodies 12.

Two lifters 52, as shown in FIG. 1, are disposed laterally in alignment with each other and are paired to support one buoyant body 12. This driven shaft 51 of the lifting means is rotated by the rotational force of the first driving shaft 31 of the drop guiding device 30. For this, pulleys 31b and 51a are fixedly mounted to the respective ends of the first driving shaft 31 and the driven shaft 51, and these pulleys 31b and 51a are connected to each other by means of a power transmitting member 81 like a belt. Further, the pulleys 31b and 51a are set such that one buoyant body 12 is separated from the conveyor 33, and another body 12 is loaded on the conveyor 33 simultaneously. This can be achieved by one of the mechanisms which are well known to those skilled in the art.

For a smooth feed of the buoyant body 12, the driven shaft 51 of the lifting means is located higher than the first driving shaft 31 of the drop guiding device 30. The buoyant body 12 picked up by the lifters 52 moves on a feeding plate 53 which is mounted over the lifting means and the drop guiding device 30 while slanting down toward the device 30, and is loaded on the supporting bars 34 of the conveyor 33.

At the both end portions of the second driving shaft 32 of the drop guiding device 30 are mounted pulleys 32b and 32c, respectively. One pulley 32b is connected to a pulley mounted to a shaft of a generator 60, which is located in a predetermined position, by a power transmitting member 82 like a belt. Thus, the rotational force of the second driving shaft 32 activates the generator 60 to generate electricity. The other pulley 32c is connected to the entering device 40 by a belt 83, which will be described in detail hereinafter.

The entering device 40 includes a decelerator 41 which receives the rotational force of the second driving shaft 32 of the drop guiding device 30 through the pulley 32c and the belt 83 and decelerates it to a desired velocity, a motion converting means which is mounted to the shaft of the decelerator 41 to convert the rotating motion of the shaft into the rectilinear motion, and a piston 42 which is coupled to the motion converting means and performs a rectilinear reciprocating motion.

Describing more in detail, the motion converting means includes a circular rotating plate 43, the center of which is fixed to the shaft of the decelerator 41, a protrusion 44 which is formed on a border of the rotating plate 43, a link 48 which is coupled to the protrusion 44

at its end, and a hinge piece 45, one end of which is hingedly coupled to the link 48 and the other end of which is hingedly coupled to the front end of a shaft 42a of a piston 42.

Furthermore, a put-in pipe 47, which contains the piston 42 therein and guides the rectilinear movement of the piston 42, is formed integrally at the lower portion of the front wall of the water tub 20. The buoyant body 12 dropped separately from the drop guiding device 30 is introduced into the put-in pipe 47 and put into the water tub 20 by the rectilinear reciprocating movement of the piston 42. The put-in pipe 47 should be located lower than the second driving shaft 32 of the drop guiding device 30 and has a predetermined length such that the pipe 47 is extended outward and inward from the front wall of the water tub 20. On the outer circumferential surface of the outwardly extended put-in pipe 47 is formed a cut portion 47a through which the buoyant body 12 separated from the drop guiding device 30 enters the put-in pipe 47. Between the second driving shaft 32 of the device 30 and the put-in pipe 47 is mounted a sliding plate 46 along which the buoyant body 12 rolls toward the cut portion 47a of the pipe 47. The sliding plate 46 slants downward while deviating at a predetermined angle, so as to move the buoyant bodies 12 toward the put-in pipe 47 disposed in front of the front wall of the water tub 20 from the drop guiding device 30 disposed laterally apart from the tub 20. Side walls 46a are formed vertically on the both side ends of the sliding plate 46 to prevent the buoyant bodies 12 from being dropped separately from the sliding plate 46.

And, around the inner circumferential surface of the inwardly extended put-in pipe 47 are provided a plurality of 0-rings 49. The water in the tub 20 is prevented from leaking outside through the pipe 47 by the contact between the buoyant body 12 and the 0-rings 49, as shown as a dotted line in FIG. 1, when the buoyant body 12 is located at the opened end of the pipe 47 inside the water tub 20.

A braking device 70 for stopping the rotating motion of the second driving shaft 32 of the drop guiding device 30 is mounted on the outer circumferential surface of the shaft 32.

The operation and effect of the electricity generating apparatus using the gravity and buoyancy according to the present invention will now be described hereinafter.

First, a user loads the buoyant bodies 12 one by one on the supporting bars 34 which are mounted to the drop surface of the conveyor 33. Of course, in this initial installation, the rotating motion of the second driving shaft 32, i. e., the drop motion of the drop guiding device 30, is not performed by the braking device 70 mounted to the second driving shaft 32.

After the completion of the initial installation work for the buoyant bodies 12, when the braking device 70 is released, the buoyant bodies 12 move down by their own weights while being guided by the drop guiding device 30.

As shown in the directions of the arrows A and B in FIG. 2, the conveyor 33 moves downward and upward, and at the same time the first and second driving shafts 31 and 32 rotate. At this time, since the protrusions 31a and

32a of the driving shafts 31 and 32 are inserted in the slots 33a of the conveyor 33 one by one, the shafts 31 and 32 are accurately engaged with the conveyor 33.

As the first shaft 31 rotates as described above, the driven shaft 51 of the lifting means connected to the shaft 31 by means of the belt 81 also rotates, so the buoyant bodies 12 floating on the water by the buoyancy are picked up by the lifters 52 of the lifting means and fed toward the drop guiding device 30 along the feeding plate 53.

Also, the rotating motion of the second shaft 32 activates the generator 60 connected to the shaft 32 by means of the belt 82, to generate electricity.

The buoyant bodies 12 dropped separately from the lower end of the drop guiding device 30 move along the sliding plate 46 and enter the put-in pipe 47 through the cut portion 47a. Then, the rotating motion of the second shaft 32 is converted into the rectilinear motion of the piston 42 via the rotating plate 43 coupled to the decelerator 41, the link 48, and the hinge piece 45, as described above. By such a reciprocating rectilinear motion of the piston 42, the bodies 12 in the put-in pipe 47 are put in the water tub 20 repeatedly.

The buoyant bodies 12 put in the water tub 20 by the piston 42 float to the water surface by the buoyancy in order, and continually circulate around the inventive electricity generating apparatus 10 by the lifting means, the drop guiding device 30, and the entering device 40, to thereby activate the generator 60 to generate the electricity.

As an example of operating the inventive electricity generating apparatus 10, the applicant of the present

invention forms each buoyant body 12 as an empty cylinder which is made from a stainless material having a diameter of 10cm, length of 30cm, thickness of 0.2cm and weight of 2.2kg, and loads the fifty buoyant bodies 12 one by one on the supporting bars 34 which are mounted to the drop surface of the conveyor 33 in the initial installation work. As a result, the electric power in the range of 700 to 1000 watts is generated from the generator 60.

Of course, the user can acquire his desired electric power by various methods of modifying the shape characteristics of the buoyant bodies 12 or the number of supporting bars 34 of the conveyor 33, or installing one or more inventive electricity generating apparatus 10 together.

When the user intends to stop the current operation of the inventive apparatus 10, the user puts the brake on the second driving shaft 32 by using the braking device 70 mounted to that shaft 32.

As described above in detail, the electricity generating apparatus of the present invention easily generates the electricity by using the gravity and the buoyancy applied to the buoyant bodies as energy sources for driving the generator. Also, since the structure of the apparatus is simple, it is convenient to install, operate and manage the apparatus. In addition, since the apparatus generates the electricity by using the nonpolluting energy sources, it contributes to the protection of environment.

While this invention has been particularly shown and described with reference to particular embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be effected therein without departing from the spirit and scope of the invention as defined by the appended claims.