Hydraulic motor with buoyant tubular members
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a hydraulic motor, and more particularly, to a novel motor in which variable volume floats are used in a piston-like manner to transmit power to a shaft or the like for remote use thereof. 
     2. Description of the Prior Art 
     Patents pertaining to this art date back to early in the century. U.S. Pat. Nos. 921,637, 1909, Vanderslice, and 1,557,290, 1925, Ippolito, both disclose a hydraulic motor in which the bouyant forces of water are used to alternately raise a pair of floats thereby imparting a rocking movement to a beam connected therebetween. U.S. Pat. No. 989,873, 1911, Rates et al, discloses a water motor in which both the buoyant forces of the water and the gravity forces thereof are alternatively used to impart a rocking movement to a beam. 
     Variations reside in the designs of the channeling control means for alternatively admitting the input water into the various compartments of the motors as well as the valve and control means for alternatively discharging the water from the compartments. 
     Such hydraulic motors are impractical. Only in water-rich, under-developed countries and perhaps in remote areas can such hydraulic motors be of use. All of the above patents disclose motors producing a power output directly proportional to the amount of water used as the various receptacles must be completely filled with water to generate forces that result in power being developed. However, the present aforementioned areas of use for hydraulic motors are normally characterized by water scarceness. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an aim of the present invention to provide an improved hydraulic motor characterized by a simple structure wherein a minimum amount of water is used to produce power. 
     It is also an aim of the present invention to use air as a replacement for a maximum amount of water. 
     It is a further aim of the present invention to alternately transfer air from one float to another, thereby providing the hydraulic motor with floats of variable volume and constant air pressure. 
     A construction in accordance with the present invention comprises a hydraulic motor including at least first and second tank means each having a bottom wall and a peripheral upstanding side wall for containing water. An upstanding first tubular member which is open-ended at the top extends upwardly from the bottm wall and is spaced inwardly from the side wall of the tank means and defines a space therewith. A second tubular member has a top wall and a peripheral side wall transversely dimensioned for telescoping onto the first tubular member and within the tank means. Guide means guides the telescopic reciprocating movement of the second tubular member relative to the first tubular member. Means supply water from a water supply source to the space between the side wall of the first tubular member and the side wall of the tank means. The water is effective to float the second tubular member and move it along the guide means to an upper limit in the tank means from a lower limit therein, i.e., to a telescopic extended position relative to the first tubular member from a telescopic compressed position. A gaseous fluid is provided within the variable volume chambers each defined by the first and second telescopic tubular members arrangement and within a conduit means communicating between the chambers, in order to maintain a constant pressure therein. Means are provided for alternately supplying to and exhausting water from the first and second tank means, whereby the telescopic first and second tubular arrangements in the respective tank means are alternately extended and compressed by means of the water rising or lowering in the space in the respective tank means. Means are coupled to the second tubular members in each of the first and second tank means for extracting the mechanical energy derived from the reciprocating movement thereof. 
     A further construction in accordance with the present invention comprises a hydraulic motor including at least a tubing means used for connecting, in a substantially horizontal way, openings defined on the side wall of each tank means. The openings are defined thereon at a level for allowing gravity transfer of substantially half the water required for moving the second tubular member from the compressed position thereof to the extended position thereof from the tank means associated with the second tubular member in the extended position thereof to the tank means associated with the second tubular member in the compressed position thereof. Each stroke of the second tubular members thus requires only substantially half the water therefor from the water supply source, as the remainder of the water required is transferred between the tank means by way of the tubing means. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
     FIG. 1 is a front elevation partly in cross-section of a hydraulic motor showing the pistons at the end of a stroke thereof; 
     FIG. 2 is a right-side elevation of the hydraulic motor, also showing the storage basin and the water supply means; 
     FIG. 3 is a top plan view of the hydraulic motor; 
     FIG. 4 is a fragmentary enlarged cross-section of the left-side elevation of FIG. 1, showing the rack and the ratchet-type gear (pinion) meshing; 
     FIGS. 5 through 9 schematically illustrate both tanks through at least a full cycle; and 
     FIG. 10 is a view, similar to FIG. 1, illustrating a modified embodiment, and more specifically, wherein an alternate means is shown for allowing the air to transfer between the pistons. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring mainly to FIG. 1, a hydraulic motor M includes first and second cylindrical tanks 10 and 11 that are open-ended at respective top ends 12 and 13 thereof for respectively receiving in a longitudinal and concentrical way first and second pistons 14 and 15 comprising respective top walls 18 and 19 and side walls 16 and 17. The pistons 14 and 15 are also of cylindrical shape and are open-ended at respective bottom ends 20 and 21 thereof. The tanks 10 and 11 have twice the height dimension of the respective pistons 14 and 15. 
     First and second racks 22 and 23 are fixedly mounted at respective bottom ends 24 and 25 thereof to respective top walls 18 and 19. Guides 26 and 27 respectively prevent the racks 22 and 23 from any lateral deviation while allowing vertical movement thereof. The racks 22 and 23 respectively mesh with first and second pinions 28 and 29 which are fixedly mounted to a shaft 30. The shaft 30 is rotatably mounted to anchored shaft supports 32. Each pinion 28 and 29 is provided with ratchet-type gear means so as to rotate only and, thus, power the shaft 30 on an upward movement of one of the respective racks 22 and 23. A detailed description of the movements involved will follow the description of the structure of the hydraulic motor M. 
     First and second elongated open cylinders 34 and 36 are mounted at a lower end thereof to a respective bottom wall of the tanks 10 and 11. The open cylinders 34 and 36, concentrically located within the tanks 10 and 11, have substantially the same height dimension as that of the pistons 14 and 15, but are of smaller diameter. The first and second open cylinders 34 and 36 communicate by way of a large diameter pipe 38 connecting a pair of openings 40 and 42 respectively defined on bottom walls 44 and 46 of the tanks 10 and 11 and within the open cylinders 34 and 36, as best seen in FIG. 1. 
     The pistons 14 and 15 and the open cylinders 34 and 36 respectively associated therewith form a pair of variable volume air chambers as the pistons 14 and 15 described a reciprocating movement onto the respective open cylinders 34 and 36 and within the tanks 10 and 11. The pipe 38 allows air to transfer from the air chamber associated with the piston 14 or 15 moving downwardly to the air chamber associated with the other piston 14 or 15 which is moving upwardly. The two variable volume air chambers and the pipe 38 thus form a constant volume air chamber, wherein, obviously, the air pressure remains substantially constant. 
     The tanks 10 and 11 contain enough water W to surround the pistons 14 and 15. The pistons 14 and 15, the open cylinders 34 and 36, and the tubing 38 are filled with air A, the pressure of which dictates the difference in the water levels on each side of the side walls of the pistons 14 and 15. 
     As the pressure of the air A remains constant throughout the reciprocating movements of the pistons 14 and 15, the water levels on each side of the side walls 16 and 17 thus remain immobile relative to the pistons 14 and 15 and, therefore, the water is unable to leak into the open cylinders 34 and 36. The water W required in the tanks 10 and 11 must surround the pistons 14 and 15 to allow the same to float under the buoyancy phenomenon. 
     To supply water to the tanks 10 and 11, a water storage basin 48 is used as well as a main supply pipe 50 (see FIG. 2). As best seen in FIG. 3, the main pipe 50 splits at a lower end thereof into a first and a second pipe 52 and 54 for respectively supplying water to the tanks 10 and 11 through a first pair of openings each being defined on a side wall of one of the tanks 10 and 11 and near the bottom wall thereof. The first and second pipes 52 and 54 open up into tanks 10 and 11 near the bottom wall thereof and are always immersed in water thereat. Because the water level in the storage basin 48 is higher than the maximum level attainable in the tanks 10 and 11, the pipes 50, 52, and 54 act as siphons to supply water to the tanks 10 and 11. 
     The evacuation of the tanks 10 and 11 is ensured by way of a second pair of openings defined on the side walls of the tanks 10 and 11, opposite the first pair of openings and low enough for the evacuation to be carried out by gravity. 
     A third and fourth pipe 56 and 58 are connected at a first end thereof to the second pair of openings. The third and fourth pipes 56 and 58 join at a second end thereof for forming a main evacuation pipe 60. 
     An increase of the amount of water W in one of the tanks 10 or 11 coupled with a corresponding reduction in the other tank results in an upward movement of the piston 14 or 15 associated with the tank 10 or 11 being filled up and in a downward movement of the other piston. Air contained in the piston 14 or 15 moving downwardly transfers to the other piston by way of the tubing 38 and the open cylinders 34 and 36. 
     Water supply and evacuation could be respectively assumed entirely by the supply pipes 50, 52, and 54 and by the evacuation pipes 56, 58, and 60. But since for every water increase in one of the tanks 10 or 11, there is a corresponding decrease in the other, a transfer pipe 62 is added, in this preferred embodiment, to connect the tanks 10 and 11. The transfer pipe 62 is located substantially midway between the maximum and the minimum level of water in the tanks 10 and 11 inside the pistons 14 and 15, as can be seen in FIG. 1, for substantially allowing half the water contained in the full tank 10 or 11 to be transferred by gravity to the other tank, thus requiring about 50% less water from the storage basin 48. 
     Solenoid valves 64, 66, 68, 70, and 72 respectively control the water flow through the first and second supply pipes 52 and 54, the first and second evacuation pipes 56 and 58, and the transfer pipe 62. 
     Mechanical-electrical switches 74, 76, 78, and 80 control the valves 64, 66, 68, 70, and 72 through relays (not shown) in a way further described hereinafter. The switches 74, 76, 78, and 80 respectively comprise a movable part 82, 84, 86, and 88. The switches 74 and 76 are fixedly mounted on a first mounting means 90, and the switches 78 and 80 are similarly mounted to a second mounting means 92 (see FIG. 1). 
     First and second actuating means 94 and 96 are respectively mounted at top ends 98 and 100 of the racks 22 and 23, extending towards the switches 74, 76, 78, and 80 (see FIG. 1). The pistons 14 and 15 each have a lower and an upper end stroke position within respective tanks 10 and 11. The piston 14, on an upward movement thereof starting at the lower end stroke position thereof, first produces an upwardly pivoting movement of the movable part 84 of the switch 76. Concurrently, the piston 15, moving downwardly from the upper end stroke position thereof, produces the downwardly pivoting movement of the movable part 86 of the switch 78. The upwardly pivoting movement of each of the movable parts 82, 84, 86, and 88 triggers a different valve response, whereas the downward movements of the same are without effect on the values 64, 66, 68, 70, and 72, in this embodiment. Therefore, for a full cylce of the motor M, starting with the piston 14 being at the lower end stroke position thereof, different signals to the valves 64, 66, 68, 70, and 72 will be alternately produced by the switches 76, 74, 80, and 78. 
     Each switch 74, 76, 78, and 80, following the upward movement of the movable parts 82, 84, 86, and 88 respectively connected thereto, release a signal for energizing the coil of one or more relays so as to produce a different and appropriate motor response from the valves 64, 66, 68, 70, and 72. 
     Switches 74 and 78 are vertically located for being substantially triggered by actuating means 94 and 96 at the end of the upward stroke of the respective pistons 14 and 15. Switches 76 and 80 are positioned for releasing a signal on the upward movement of the respective pistons 14 and 15 substantially at half stroke thereof, i.e. when the quantity of water W in each of the tanks 10 and 11 is equal. 
     FIGS. 5 through 9 illustrate the successive filling and emptying of the tanks 10 and 11 with the use, where applicable, of the transfer pipe 62. The arrows show the water level directions. FIGS. 6 through 9 show a full cycle of the motor M, each illustrating a water level for which one of the switches 74, 76, 78, and 80 releases a signal. FIG. 5 shows an intermediate level for which no signal is given to the valves. 
     In FIG. 5, the water level in the first tank 10 increases as a result of water from the storage basin 48 flowing through the pipes 50 and 52 and the open valve 64 into the tank 10. Simultaneously, water flows out of the second tank 11 by way of the pipes 58 and 60 and the open valve 70. The valves 66, 68, and 72 are in the closed position thereof. Through the pipe 38, the air A transfers from the second pistion 15 to the first piston 14 which are following the water levels and keeping the air presssure constant. The first actuating means 94 of the first rack 22 moves upwardly towards the movable part 82 of the switch 74. The actuating means 94 causes the movable part 82 to pivot upwardly as the water in the tank 10 reaches the maximum level thereof and the water in the tank 11, the minimum level thereof (see FIG. 6). The switch 74 sends a signal to close valves 64 and 70 and to open the valve 72 which controls the water flow through the transfer pipe 62. 
     From FIG. 6 to FIG. 7, water transfers by gravity from the first tank 10 to the second tank 11 through the transfer pipe 62. Air transfers from the first piston 14 to the second piston 15, the pistons 14 and 15 respectively moving downwardly and upwardly. When the water is substantially level with the transfer pipe 62, the water levels in both tanks 10 and 11 are similar and the transfer by gravity is no longer possible (see FIG. 7). However, at that level, the second actuating means 96 of the second rack 23 which is moving upwardly causes the movable part 88 of the switch 80 to pivot upwardly, thus sending a signal for opening the admission valve 66 for the tank 11 and the evacuation valve 68 for the tank 10 and for closing the valve 72 of the transfer pipe 62. 
     Therefore, from FIG. 7 to FIG. 8, water is admitted to the tank 11 and evacuated from the tank 10 respectively by way of the open valves 66--and the pipes 50 and 54--and 68--and the pipes 58 and 60. Air continues to transfer from the downwardly moving first piston 14 to the upwardly moving second piston 15 through the pipe 38. When the water in the tank 11 reaches the maximum level thereof (see FIG. 8), the second actuating means 96 causes the movable part 86 of the switch 78 to pivot upwardly, thus sending a signal for closing the valves 66 and 68 and for opening the valve 72 on the transfer pipe 62. 
     From FIG. 8 to FIG. 9, water transfers by gravity from the second tank 11 to the first tank 10 through the transfer pipe 62 and the valve 72 mounted thereon, as all other valves are in the closed position thereof. The pistons 14 and 15 follow the water levels of the respective tanks 10 and 11 as air transfers from the second piston 15 to the first piston 14. When the water levels coincide (see FIG. 9), the transfer of water by gravity is replaced by the storage basin 48 supplying water to the first tank 10 through the admission valve 64 and by water drainage of the second tank 11 through the evacuation valve 70. The valves 64 and 70 are opened while the valve 72 on the transfer pipe 62 is closed following the signal released by the switch 76 which resulted from the upward movement of the rack 22. As the water levels reach that seen in FIG. 6, the cycle hereinabove described (FIGS. 6 through 9) starts over and is repeated so as to rotatably drive the shaft 30, allowing the power developed by the hydraulic motor M to be available in a simple way for use thereof. 
     As previously mentioned, the tanks 10 and 11 have substantially twice the height dimension as the pistons 14 and 15 and of the open cylinders 34 and 36. The downward stroke of the pistons 14 and 15 is limited by the top walls 18 and 19 thereof nearing respective top ends 106 and 108 of the open cylinders 34 and 36. Thus, the pistons 14 and 15 and the open cylinders 34 and 36 require substantially the same height dimension. For the water W not to leak into the open cylinders 34 and 36 through the top ends 106 and 108 thereof, the bottom ends 20 and 21 must always cover at least part of the open cylinders 34 and 36. Thus, the height dimension of the tanks 10 and 11 need not exceed substantially twice that of the pistons 14 and 15. 
     The amount of water W required is that needed to surround the pistons 14 and 15, thus avoiding air A leaking from the previously defined cnstant volume air chamber and allowing pistons 14 and 15 to float. Therefore, the differences between the diameters of the tanks 10 and 11, the pistons 14 and 15, and the open cylinders 34 and 36, are determined by the requirement of having enough water W to surround the pistons 14 and 15 to provide buoyance and by the precision of the construction of the motor M. The differences between the aforementioned diameters tend to be minimal within those limits so that the motor M requires a minimum amount of water per cycle. 
     The limits pertaining to the construction of the motor M are determined by the verticality of the side walls of the tanks 10 and 11, the pistons 14 and 15, and the open cylinders 34 and 36, and also on the verticality, stability, and consistency of the reciprocating movement of each of the pistons 14 and 15, and thus on the guides 25 and 26 and on the proper meshing of the pinions 28 and 29 with respective racks 22 and 23. 
     In a specific example, the tanks 10 and 11 each have a diameter of 2.0 m. and a height jof 2.0 m. The pistons 14 and 15 each have a diameter of 1.80 m. and a height of 1.0 m. The open cylinders 34 and 36 each have a diameter of 1.60 m. and a height of 1.0 m. These dimensions provide a distance of 10 cm. between the adjacent side walls of the tanks 10 and 11, the pistons 14 and 15, and the open cylinders 34 and 36. 
     In another embodiment, seen in FIG. 10, the air A transfers alternately between the first and second pistons 14 and 15 by way of a flexible tube 138 connecting a pair of openings 102 and 104, defined respectively on the top walls 18 and 19 thereof, thus replacing the openings 40 and 42 defined on the respective bottom walls 44 and 46 of each of the tanks 10 and 11 and the pipe 38 connected thereto, which are best seen in FIG. 1. 
     To summarize, the present hydraulic motor, when compared with the prior art, replaces a large amount of the water needed by air contained in a pair of coupled variable volume floats. Basically, the amount of water used is that which is needed to surround the floats. A large quantity of water is, therefore, economized. The transfer pipe 62 saves approximately an additional 50% of water. The high fluidity of the air results in minimum energy losses. The air A transfers from one float to the other in a closed cycle, the pressure thereof thus remaining constant. The air pressure inside the floats accounts for the difference in the water levels on each side of the side walls of the pistons. The alternate reciprocating movement of the pistons imparts, through rack and ratchet-type pinion means, a rotating motion to a shaft to provide a power output.