Apparatus for generating rotary motion from rise and fall motion of waves

An apparatus for generating rotary motion from rise and fall motion of waves includes an outer hollow sleeve, a float sealably attached across the upper end of the outer sleeve to define an interior cavity, prevent entry of water into the cavity and provide the outer sleeve with sufficient buoyancy to floatably follow up and down motion of waves, an inner hollow sleeve fitted telescopically within the outer sleeve, and an anchoring arrangement attached to the inner sleeve for restraining it from following up and down motion of waves with the outer sleeve and float. The outer sleeve will slidably move up and down relative to the inner sleeve as the outer sleeve and float floatably follow up and down motion of waves and correspondingly will draw a flow of water upwardly and force a flow of water downwardly through the inner sleeve. The apparatus also includes a single rotary motion-producing mechanism mounted within the inner sleeve intersecting and engaging the flow of water through the inner sleeve. The rotary mechanism includes a rotary shaft and a turbine rotor mounted on the shaft for rotation therewith. The rotor has a set of hinged blades being pivotally reversable in their deflected positions in response to change in direction of the flow of water upwardly and downwardly through the inner sleeve for continuously rotating the shaft in a single direction.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention generally relates to wave energy conversion and, more 
particularly, is concerned with an apparatus for generating rotary motion 
from rise and fall motion of waves. 
2. Description of the Prior Art 
One of the more promising renewable sources of energy is ocean waves. Many 
devices have been proposed in prior art patents and literature for 
converting the energy of waves into a mechanical motion for performing 
work, such as generating electricity. In an article appearing in the 
September 1979 issue of IEEE Spectrum magazine entitled "Exploiting Wave 
Power", B. M. Count states that the first recorded patent was granted in 
1799 to a Frenchman, M. Girard. Count goes on to state that all wave-power 
inventions to date have been conceptually simple--floats, flaps, sloping 
ramps or other "wave traps," or stationary air-pressure chambers and 
similar devices. He cites the emergence of two major categories of 
devices: dynamically active devices and passive devices. In the active 
device, the structural elements move in response to the wave, with power 
being extracted through the relative motion of the elements. A passive 
arrangement captures the wave energy with a relatively large, immovable 
structure. Being both bulky and relatively inefficient, passive devices 
are the least promising among suggested wave-power conversion schemes. 
In a paper given in 1988 in Honolulu, Hawaii, entitled "Wave Energy: A 
Survey of Twelve Near-Term Technologies", investigators George Hagerman 
and Ted Heller grouped the major technologies for wave power conversion 
into five categories: heaving devices, heaving and pitching devices, 
pitching devices, oscillating water columns, and surge devices. Heaving 
devices use only the vertical motion of floats on waves to stroke various 
types of pumps. Combined heaving and pitching devices absorb energy from 
two or more motions of the waves, such as heave, pitch and roll. Pitching 
devices can be either floating or fixed. An oscillating water column 
device employs wave-induced motion of an entrained column of seawater as 
the driving force. Surge devices make use of a wave's forward horizontal 
force. 
Notwithstanding the many different kinds of devices and approaches proposed 
in the prior art for capturing and converting wave energy to a form of 
motion for performing useful work, many technical problems still remain in 
harnessing wave energy. An optimal device has not yet appeared on the 
horizon. 
SUMMARY OF THE INVENTION 
The present invention provides an apparatus for generating rotary motion 
from rise and fall motion of waves, such as in ocean tides. The apparatus 
employs a pair of relatively slidable inner and outer cylinders or sleeves 
being telescoped together, and a rotary motion-producing mechanism mounted 
to the inner sleeve and responsive to flow of water therethrough in each 
of two opposite directions for generating rotary motion continuously in 
only a single direction. 
A prior art U.S. Pat. No. 4,284,901 to Giguere discloses an apparatus 
composed of a floating island installed on a column stationarily mounted 
to the ocean floor. The floating island moves vertically in telescoping 
fashion relative to the fixed column in response to rise and fall of ocean 
waves. The apparatus of the Giguere patent has separate water flow 
circuits through the top portion of the column which are used alternately 
for rotatably driving separate turbines mounted on the same shaft. One 
circuit is used when the island floats upward causing flow of water 
upwardly therethrough, whereas the other circuit is used when the island 
floats downward causing flow of water downwardly therethrough. Check 
valves are interposed in the circuits to prevent reversal of the direction 
of water flow through the circuits. 
In contrast thereto, the apparatus of the present invention employs a 
single rotary motion-producing mechanism that will be rotated in only one 
direction by flow of water in either direction through the inner sleeve 
and the rotary mechanism. In one exemplary embodiment, the mechanism is a 
turbine rotor having a set of radial pivotally reversable hinged blades. 
Accordingly, the present invention is directed to an apparatus for 
generating rotary motion from rise and fall motion of waves, comprising: 
(a) a first hollow tubular member having upper and lower opposite open 
ends; (b) a float sealably attached across the upper end of the first 
tubular member so as to define an interior cavity therewith and prevent 
entry of water through the upper end of the first tubular member into the 
cavity, the float also providing the first tubular member with sufficient 
buoyancy to floatably follow up and down motion of waves with the float 
when the float and first tubular member are disposed in a body of water; 
(c) a second hollow tubular member having top and bottom opposite open 
ends and fitted telescopically with the first tubular member, the second 
tubular member defining a flow path for water from the bottom open end of 
the second tubular member to the cavity of the first tubular member and 
float; (d) means attached to the second tubular member for restraining the 
second tubular member from following up and down motion of waves with the 
first tubular member so as to cause the first tubular member to slidably 
move up and down relative to the second tubular member as the first 
tubular member and float floatably follow up and down motion of waves and 
correspondingly draw a flow of water upwardly into the cavity from along 
the flow path through the second tubular member and force a flow of water 
downwardly from the cavity along the flow path through the second tubular 
member; and (e) a single rotary motion-producing mechanism mounted within 
the second tubular member in engagement with the flow of water through the 
second tubular member, the rotary mechanism being capable of rotating in a 
single direction in response to flow of water both upwardly and downwardly 
through the second tubular member and against the rotary mechanism. 
The rotary motion-producing mechanism includes a shaft having an axis of 
rotation, and means for rotatably mounting the shaft to the second tubular 
member so as to extend through the second tubular member for rotation of 
the shaft about the axis. Also, the rotary mechanism includes a driving 
member having a hub mounted to the shaft for rotation therewith, a 
plurality of spokes mounted to the hub and displaced about and extending 
radially from the hub, and a set of blades each being hingedly mounted to 
one of the spokes so as to permit pivoting of the blade about the 
respective spoke between a pair of angularly displaced positions in 
response to a change in the direction of flow of water through the second 
tubular member. The blade in each of the respective positions opposes the 
flow of water in the particular direction along the flow path through the 
second tubular member so as to produce revolution of the blade and 
continuous rotation of the shaft in the one direction about the axis of 
the second tubular member in response to flow of water in each of the 
opposite directions through the second tubular member. 
More particularly, the second tubular member is an inner cylinder or sleeve 
and the first tubular member is an outer cylinder or sleeve telescopically 
inserted over the inner sleeve and reciprocally movable along the inner 
sleeve. The second tubular member also includes an interior annular body 
portion attached to the inner sleeve and forming a central passage through 
the inner sleeve which defines the water flow path. The interior annular 
body portion of the inner sleeve defines a flotation cell which provides 
buoyancy to the second tubular member. The driving member of the rotary 
mechanism is mounted by the rotary shaft within the interior annular body 
portion of the inner sleeve with the set of blades extending radially 
outward across the central passage. The restraining means includes an 
anchor resting stationarily within the body of water and a tether 
interconnecting the anchor and the second tubular member for permitting 
the second tubular member and rotary mechanism to sway horizontally to 
accommodate the driving force of a passing wave while restraining the 
second tubular member from moving up with the motion of the passing wave. 
These and other features and advantages of the present invention will 
become apparent to those skilled in the art upon a reading of the 
following detailed description when taken in conjunction with the drawings 
wherein there is shown and described an illustrative embodiment of the 
invention.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to the drawings, and particularly to FIG. 1, there is shown an 
apparatus, generally designated 10, for generating rotary motion from rise 
and fall motion of waves W in accordance with the principles of the 
present invention. In its basic components, the rotary motion generating 
apparatus 10 includes a pair of hollow tubular members 12 and 14, a float 
16 mounted to the upper portion of the one tubular member 12, and a single 
rotary motion-producing mechanism 18 mounted within the other tubular 
member 14. 
Preferably, the tubular members 12 and 14 of the apparatus 10 are in the 
form of outer and inner cylinders or sleeves, which each have upper and 
lower opposite open end portions 12A, 12B and 14A, 14B. The outer sleeve 
12 fits telescopically over the inner sleeve 14. The internal diameter of 
the outer sleeve 12 is slightly greater than the external diameter of the 
inner sleeve 14 so that the outer sleeve 12 can slide in a reciporatory 
manner along the outside surface of the inner sleeve 14. 
The float 16 is in the form of an annular body of larger diameter than the 
outer sleeve 12 and having a generally conical-shaped upper surface 16A 
and annular conical-shaped lower surface 16B. The float body 16 can be 
hollow and filled with air or be solid and composed of a material less 
dense than water. The float body 16 has a central opening 17 at its lower 
surface 16B through which extends the upper open end portion 12A of the 
outer sleeve 12. The float body 16 is sealably attached at the interior 
side of its upper surface 16A to the upper end portion 12A of the outer 
sleeve 12 so as to define an interior cavity 20 therewith and prevent 
entry of water through the upper end 12A of the outer sleeve 12 into the 
cavity 20. The float 16 is sufficiently lightweight compared to the volume 
of water it displaces so as to provide itself and the outer sleeve 12 with 
sufficient buoyancy to floatably follow the up and down motion of waves W 
in a body of water. 
The inner sleeve 14 has an interior annular body portion 22 attached to the 
interior cylindrical surface 14C of the inner sleeve 14 intermediately 
between its opposite upper and lower ends 14A, 14B. The interior annular 
body portion 22 defines a central passage 24 through the inner sleeve 14. 
The annular body portion 22 has upper and lower annular surfaces 22A and 
22B of conical shapes converging toward one another to the central passage 
24 which function to funnel the flow of water to the passage. Also, the 
interior annular body portion 22 of the inner sleeve 14 can be solid and 
composed of a material less dense than water, or can be hollow forming a 
sealed annular cavity filled with air. In either case, the annular body 
portion 22 defines a flotation cell which provides a certain amount of 
buoyancy to the inner sleeve 14. 
In order to ensure relative motion between the outer and inner sleeves 12 
and 14 in response to the rise and fall motion of the waves W, the inner 
sleeve 14 is held generally stationary in the body of water with respect 
to the vertical direction. To achieve this, the apparatus 10 also includes 
means in the form of an anchoring or mooring arrangement 26 attached to 
the inner sleeve 14 which restrains it from following the up and down 
motion of the outer sleeve 12 and float 16 as caused by the corresponding 
motion of the waves. In one exemplary form, the anchoring arrangement 26 
is a platform or anchor 28 resting stationarily within the body of water, 
and a tether or rod 30 interconnecting the anchor 28 and the lower end 14B 
of the inner sleeve 14. The inner sleeve 14 is permitted by the anchoring 
arrangement 26 to sway from side-to-side horizontally to accommodate the 
driving force of a passing wave while, at the same time, being restrained 
by the arrangement 26 from moving upward with the motion of the passing 
wave. With the inner sleeve 14 so restrained, the outer sleeve 12 will 
slidably reciprocate or move up and down relative to the inner sleeve 14 
as the outer sleeve 12 and float 16 floatably follow and are carried up 
and down between crest and trough elevations of the wave by the motion of 
wave. 
Upward movement of the outer sleeve 12 and float 16 relative to the 
stationary inner sleeve 14 from the position of FIG. 1, as the outer 
sleeve 12 and float 16 are carried with the ascending crest of a wave, 
expands the volume of the interior cavity 20 defined by the outer sleeve 
12 and float 16 generally above the level L of the water within the inner 
sleeve 14. Expansion of the volume of the cavity 20 creates a partial 
vacuum condition within the expanded volume which draws or sucks a flow of 
water upwardly through the central passage 24 of the annular body portion 
22 of the inner sleeve 14. The creation of the partial vacuum condition 
between the float 16 and outer sleeve 12 and the water level L in the 
inner sleeve 14 limits the amount of ascent of the outer sleeve 12 and 
float 16 relative to the inner sleeve 14 so as to prevent the outer sleeve 
12 from slipping off the inner sleeve 14. 
Downward movement of the outer sleeve 12 and float 16 relative to the 
stationary inner sleeve 14 from the position of FIG. 1, as the outer 
sleeve 12 and float 16 are carried with the descending trough of the wave, 
contracts the volume of the cavity 20 defined by the outer sleeve 12 and 
float 16 above the level L of the water within the inner sleeve 14. This 
forces a flow of water downwardly through the passage 24 of the annular 
body portion 22 of the inner sleeve 14 and from the open lower end 14B 
thereof. The buoyancy of the inner sleeve 14 tends to maintain its 
stability in the water and limit the maximum amount the outer sleeve 12 
and float 16 can descend in the water. 
Referring to FIGS. 2 and 3, there is illustrated the rotary 
motion-producing mechanism 18 of the apparatus 10 which is mounted within 
the central passage 24 of the interior annular body portion 22 of the 
inner sleeve 14, as seen in FIG. 1. In such location, it intersects the 
flow of water through the central passage 24 of the inner sleeve 14. The 
rotary mechanism 18 is capable of rotating in a single direction in 
response to flow of water both upwardly and downwardly through the central 
passage 24 of the inner sleeve 14. 
More particularly, the rotary mechanism 18 includes an enlongated shaft 32 
having an axis A of rotation, and a pair of spider-like structures 34 
which rotatably mount the shaft 32 through the passage 24 of the inner 
sleeve 14. Each structure 34 includes a bearing 36 and a plurality of 
streamlined struts 38 connected to the bearing 36. The struts 38 of each 
structure 34 extend radially from the bearing 36 and are connected to the 
annular body portion 22 so as to stationarily mount the bearings 36 in 
axial alignment with one another, positioning the rotary shaft 32 
coaxially through the passage 24. 
Also, the rotary mechanism 14 includes a driving member 40 in the form of a 
propeller of rotor. The rotor 40 has a central hub 42 mounted to the 
rotary shaft 32 for rotation therewith, a plurality of spokes 44 mounted 
to the hub 42 and displaced circumferentially about and extending radially 
from the hub 42 and with respect to axis A of the shaft 32. A set of 
blades 46 are hingedly mounted to the respective spokes 44 so as to pivot 
about the spokes between a pair of angularly displaced positions shown 
respectively in FIGS. 2 and 3, and in solid and dashed lines in FIG. 4, in 
response to a change in the direction of flow of water through the central 
passage 22 of the inner sleeve 14. A pair of stops 48 having generally 
C-shaped configurations are fixedly mounted at the opposite ends of the 
spokes 44 and overlie opposite edges of the hinge portions 46A of the 
blades 46 so as to limit the blades 46 to about a 30.degree. deflection in 
either direction away from the horizontal position shown in FIG. 1. 
FIG. 2 illustrates an upwardly deflected position of the blades 46 when 
water flows upwardly through the central passage 22. FIG. 3 illustrates a 
downwardly deflected position of the blades 46 when water is flowing 
downwardly through the central passage 22. The blades 46 change deflected 
positions in response to the change in direction of the flow of water 
through the passage 22 but only deflect about 30.degree. due to the 
presence of the stops 48 so that in each of the respective positions the 
blades 46 are engaged by and oppose the flow of water in the given 
direction through the inner sleeve central passage 22. Opposition to the 
flow of water by the blades 46 causes the flowing water to drive the 
blades 46 and produce revolution of the blades 46 and rotation of the 
shaft 32 continuously in the one direction about the axis A of the central 
passage 22 of the inner sleeve 14 irrespective of the particular direction 
of flow of water through the inner sleeve 14. In the illustrated example, 
the rotor 40 has eight flat blades 46, each defining a 45.degree. arc at 
the outer edge 46B thereof. 
Although not part of the present invention, the rotary shaft 32 can be 
coupled to any suitable mechanism for converting the rotary motion of the 
shaft 32 into another motion for use in producing work. In FIG. 1, the 
rotary shaft 32 is shown coupled by a vertical extension shaft 50 to an 
electrical generator 52 mounted on the platform or anchor 28. 
In summary, passing crests and troughs of waves make the float 16 rise and 
fall (go up and down) with the wave which, in turn, causes the outer 
sleeve 12 to slidably move vertically and cyclically up and down relative 
to the more or less stationarily-held inner sleeve 14. The up and down 
reciprocal movement of the outer sleeve 12 alternately draws water 
upwardly through the inner sleeve 14 by creation of suction forces in the 
cavity 20 and forces water downwardly through the inner sleeve 14. The 
blades 46 are deflected between their up and down positions in response to 
change in direction of the water flow through the passage 24. Irregardless 
of the deflected position of the blades 46 and the direction of water flow 
through the inner sleeve 14, the blades 46 continue to rotary the shaft 32 
in the same direction. 
It is thought that the present invention and its advantages will be 
understood from the foregoing description and it will be apparent that 
various changes may be made thereto without departing from its spirit and 
scope of the invention or sacrificing all of its material advantages, the 
form hereinbefore described being merely preferred or exemplary embodiment 
thereof.