Note: Descriptions are shown in the official language in which they were submitted.
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OSCILLATING PROPULSOR
1. TECHNICAL FIELD
The present invention relates to propulsion systems and, more particularly, to
devices that propel
fluids and crafts in oscillation mode.
2. BACKGROUND ART
Over time, man has developed tools to help him propel and navigate his crafts
over land and in
bodies of fluid, be they lakes, rivers, oceans or the atmosphere. These tools
have evolved from
sticks, paddles, oars, hot air balloons and bird-like wings to today's state
of the art wings and
propeller screws. The propeller screw and its many modifications form the
basis of most current
propulsion systems. Design and manufacture of the propeller screw requires
mastery of foil
dynamics in which profile, shape, area, angle, number of blades, and speed are
important
parameters. Moreover, the phenomena of cavitation and stall limit the
performance of the
majority of propeller screws. Propeller screws are also sometimes lethal to
wildlife.
There is an effort to develop alternative propulsion systems in the form of
reciprocating wings,
with a promise of greater efficiency. Most engines in use today are of the
reciprocating type, yet
they are invariably used in rotary mode; the mechanical simplification
afforded by direct drive of
oscillating propulsion systems would be a major advantage. Reciprocating
propulsion systems
may also be better suited to harnessing wave power for propulsion, further
increasing efficiency
and helping to preserve the environment through reduced hydrocarbon use.
However, current
reciprocating propulsion systems are still based mostly on the airfoil or
hydrofoil concept and
can be expected to suffer from some of the limitations of the propeller screw,
as already
outlined.
A different approach to fluid propulsion involves imparting energy to a
contained volume of
fluid before discharge; other than enclosed propellers it appears that piston
and diaphragm
pumps, and the likes are the existing alternatives, with limited market
success in craft
propulsion. A submersible buoyant cup with transverse opening is disclosed in
US pat. No.
3,236,203 to Bramson (1966): this design is based on raising a volume of water
in the cup from
a body of water to a height above the body of water for release under the
influence of gravity.
Drainage of water from the cup imparts a reaction force to the cup. Thrust
from Bramson (1966)
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device is limited by the gravity of the Earth, a relatively constant force.
The potential power of
this design is also limited by the diameter of the cup, since discharge of
water at a height greater
than the diameter of the cup may not add substantially to propulsion; the cup
would start
discharging its content as soon as it emerges from the water body and would be
completing its
discharge by the time the whole cup is out of the water body, depending off
course on the
dimensions of the cup. On the other hand, the time required to fill the cup
under water would
also be similarly limited by the cup dimensions and the potential for air
entrapment within the
cup. The above limitations imply a maximum stroke rate and speed for the
device, governed by
cup dimensions, geometry, gravity, and fluid dynamics considerations. Bramson
(1966)
propulsion device must surface to produce thrust. To this end the geometry and
buoyancy of the
cup are for water retention and conveyance to the surface and not for
submerged operation. The
need to surface also reduces efficiency since thrust would be produced mostly
at the end of the
upward stroke, as water egresses from the cup.
The novel oscillating propulsor of the present disclosure can operate fully
submerged. The
unique geometry and operation of the oscillating propulsor provide for cyclic
acceleration and
ejection of a volume of fluid to enable displacement and produce thrust. Other
objects and
advantages of my invention will become apparent from the detailed description
that follows and
upon reference to the drawings.
3. BRIEF DESCRIPTION OF THE DRAWINGS
A complete understanding of the present invention may be obtained by reference
to the
accompanying drawings, when considered in conjunction with the subsequent,
detailed
description, in which:
Figure 1 is a perspective view of one embodiment of the oscillating propulsor;
Figure 2 is a perspective view of a spherical body with flat end caps showing
alternative
attachments of the actuating member;
Figure 3 is a perspective view of a spherical body with spherical end caps;
Figure 4 is a perspective view of the embodiment of FIG. 3 at minimum length
limit;
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Figure 5 is a chart view of the influence of size and geometry on thrust in
water for a spherical
body of 38 mm radius, oscillated at 30 strokes/sec and a stroke length of 19
mm;
Figure 6 is a perspective view of an oscillating propulsor fitted with a drag
reduction member;
Figure 7 is a perspective view of an oscillating propulsor with an intake
opening across the
leading and trailing surfaces of the spherical body;
Figure 8 is a perspective view of an oscillating propulsor fitted with fore
and aft fins;
Figure 9 is a section view of an oscillating propulsor fitted with lubricant
inlet and outlet for
provision of a lubricant cavity over the apparatus;
Figure 10 is a section view of an oscillating propulsor showing a pressure
chamber with
apertures, lubricant outlet and drag reduction member;
Figure 11 is a section view of an oscillating propulsor showing lubricant
delivery to pressure
chamber and egress to leading surface through the apertures shown in FIG. 10;
Figure 12 is a perspective view of a stylized catamaran watercraft propelled
by the oscillating
propulsor;
Figure 13 is a perspective view of an oscillating propulsor with a levered
actuating member;
Figure 14 is a perspective view of a stylized watercraft propelled by
swivelling actuation of the
oscillating propulsor of FIG. 3;
Figure 15 is a perspective view of a watercraft propelled by the action of and
the reaction to a
reciprocating motive power source on the oscillating propulsor;
Figure 16 is a perspective view of a muscle powered watercraft propelled by
the action of and
the reaction to the reciprocating motive force of an operator;
Figure 17 is a perspective view of a thrust vectoring embodiment of the
oscillating propulsor;
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Figure 18 is perspective view of a stylized aircraft propelled by the
oscillating propulsor in air
d water; and
Figure 19 is a perspective view of a muscle powered aircraft propelled by the
oscillating
propulsor.
OSCILLATING PROPULSOR
4. DISCLOSURE OF INVENTION
Structure and operation
A vessel with a spherical surface, a part sphere, can be made out of metal,
polymer, composite
materials or a combination therefrom. Any other material suitable and
appropriate for the
application cirmcumstances of use can also be utilized: corrosion resistant
stainless steel
sheeting, for marine applications, is one example. Tubing, canisters and
spheres available on the
market can be modified and joined to make the vessel. The apparatus may also
be made by any
of or a combination of stamping, rolling, extrusion, moulding, casting,
forging or machining of
metals, sheeting, or polymers. Any other suitable fabrication method can be
used. Joining can
be done by welding or other fastening methods, for example, rivets. However, a
streamlined
fluid dynamic profile, hydrodynamic or aerodynamic, is advantageous for low
drag.
Neutral or positive buoyancy of the apparatus in the ambient fluid can be used
to eliminate the
gravitational load associated with the mass of the apparatus during
oscillation; this can be
achieved by double walled, cored construction enclosing a medium whose density
is lower than
that of the ambient fluid; helium or hydrogen could be used for operation in
an atmosphere for
example. Expanded polymer foams such as polystyrene and polyurethane are
examples of
coring that can be used to achieve a desired buoyancy level in water. When not
in use, a
buoyant oscillating propulsor could automatically reposition to the shortest
distance from its
craft, at the top of stroke position; this would lessen the risk of
oscillating propulsor damage by
collision with obstacles in the ambient fluid, be it in water or the
atmosphere, for examples.
Materials and methods for fabrication of metals, polymers and composites
products are known to
those skilled in the art and can be applied to the manufacture of the
apparatus. A cylinder with a
longitudinal cut out or opening is positioned over a water body, in a
longitudinally parallel
attitude to the surface of the water, with the opening at about 90 degrees
angle to the surface of
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the water. Upon submersion, water is admitted into the cylinder. Vertical
acceleration of the
cylinder in the position described, followed by a sudden stop causes the
accelerated water to be
ejected from the longitudinal opening, along the curvature of the inner
concave surface; reversal
of the actuation stroke causes a similar ejection stream; the direction of the
cyclical ejection
5 streams thus created is influenced by the size of the longitudinal
opening; the wider the opening
the more parallel the cyclical ejection streams become and the greater the
thrust; at an opening
width about the size of the sphere diameter, the ejection streams become
parallel and thrust nears
maximum value; cutting the opening width past cylinder diameter size or the
middle of the
sphere shape, results in diverging ejection streams. The volume of fluid
enclosed and ejected is
also reduced as the segment of sphere is reduced. The size reduction and
divergent ejection angle
result in reduced thrust. The geometry dynamics disclosed provide efficient
conversion of fluid
power into thrust, within the rules of fluid dynamics pertinent to each
context. It would be
obvious to one skilled in the art to provide a variety of geometrical shapes
without departing
significantly from the spirit of the present invention.
The apparatus can be held and actuated by hand motion or placed in a guide for
actuation; it may
also be actuated by the rocking and rolling motion of a ship to which it is
attached. A handling
stick for reciprocating actuation can also be joined to the cylinder at about
the mid-points of the
length and the diameter, for example. This construction allows a balanced
movement when the
assembly is stroked up and down or swiveled from side to side. Alternatively,
handling sticks
may be joined to the ends of the cylinder or to any cylinder location
convenient and effective for
operation. The sticks can be made out of tubing or bar of metal, polymer or
composites; any
other material suitable for the context of use can be utilized for
construction of the apparatus of
this disclosure. Examples of criteria for suitable materials include fatigue
and corrosion
resistance, durability, ease of fabrication and other characteristics
pertinent to the fluid and
context of use.
5. MODES FOR CARRYING OUT THE INVENTION
For purposes of clarity and brevity, features whose function is the same or
basically the same
will be identified in each figure or embodiment by a prefix of the figure
number the variant
feature appears in, followed by the feature number, the feature number being
the same for all
variants. Examples of embodiments of the oscillating propulsor will be
described first, followed
by examples of embodiments making use of drag reduction attachments and thrust
vectoring
features; industrial applications of the oscillating propulsor will complete
the description.
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Basic embodiments ¨ FIGS. 1 - 4
FIG. 1 illustrates one embodiment of the oscillating propulsor of this
disclosure: a spherical
body 130, having a convex leading surface, and a concave trailing surface.
This embodiment is
designed for hand operation to propel fluids and produce thrust upon
reciprocating animation or
actuation, as shown in phantom lines; ambient fluids are accelerated and
ejected from the
spherical body 130 at the end of each stroke, as indicated by arrows.
Apparatus diameter can be
advantageously designed to fit the operator's hands. A strap or handle may be
installed for ease
of handling. The spherical body 130 can also be guided by a sliding mechanism
or by an
engaging channel, for ease of manual operation. This embodiment can be used as
a fluid mixer;
it can also be used as a thruster in boating and swimming, where buoyancy is
an additional
embodiment.
In another embodiment of the oscillating propulsor the spherical body 130 is
secured to an
actuating member 132. The actuating member 132 may be fitted with an aperture
134 for
fastening to a motive power source such as a reciprocating engine (not shown).
For example, the
apparatus can be animated by bolting the actuating member 132 to the conrod or
an extension
thereof of a reciprocating engine. The actuating member 132 can be
mechanically coupled to a
motive power source by any other safe and suitable means. Where animation of
the apparatus is
provided by muscle power, such as in leisure or sport crafts, the actuating
member 132 can be
made to a length ergonomically efficient for the operator, as dictated by
mechanical advantage
leverage requirements. The actuating member 132 is attached to the spherical
body 130 in a
position suitable for animating the spherical body 130; examples of attachment
to the leading
surface and alternatively to the trailing surface and the ends are shown in
FIG. 2, alternatives
being indicated by phantom lines. FIG. 3 illustrates another alternative
attachment of the
actuating member 332 across the spherical body 330. Movement of the actuating
member 32 can
be guided by an embracing sleeve or bushing, secured to a supporting base or
craft: a square
embrace can be used to fix thrust orientation whereas a round, rotatable
embrace can be used
where change of thrust direction is required, for steering and maneuvering,
for examples.
As illustrated in FIG. 2 the spherical body 230 may be reinforced with a flat
end cap 236. The
flat end cap 236 provides an alternative attachment structure for the
actuating member 232. The
flat end cap 236 can also be used to attach the apparatus to a base or craft.
As illustrated in FIG. 3 the spherical body 330 may also be reinforced with a
spherical end cap
338. The spherical end cap 338 maximizes thrust generation from fluid leaving
the apparatus
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with a longitudinally directed momentum, as would happen when the oscillating
propulsor is
swiveled end to end. A swivel mechanism, affixed to a craft, can be a hinge
type joint, for
example. If fixed to a ship, the rolling movement of the ship at sea would
provide a similar
motion to generate thrust from wave action. The heaving motion of a ship at
sea would also
generate thrust from the apparatus by reciprocating, up and down movement.
When reduced to minimum length, the oscillating propulsor shown in FIG. 3
becomes a portion
or segment of a sphere, as illustrated in FIG. 4.
Embodiment dynamic geometry - FIG. 5
The geometry of the spherical body 30 shows a remarkable influence on the
thrust generated
upon oscillation in water (FIG. 5). Whilst an optimum size in the range 0.5-
0.6 diameter fraction
is indicated in FIG. 5, it would be obvious to one skilled in the art that the
optimum value may
change with changes in fluid properties and dynamics; for example it is known
that the speed of
fluid flow over a sphere affects the location of flow separation and start of
turbulence on the
sphere, the location migrating down flow as speed increases; these factors in
turn influence drag
and thus would also influence the efficiency of propulsion generated. Thus,
whilst a half sphere
may clearly demonstrate the principle of the apparatus herein disclosed, the
optimum geometry
or portion of a sphere may be dependent on the nature of the fluid and the
context of use. It
would be obvious to one skilled in the art to provide a variety of geometrical
shapes to vector
fluid flow over and out of the apparatus without departing significantly from
the scope of the
present invention.
Embodiments with drag reduction attachments and features- FIGS. 6-11
Embodiment making use of hydrophobic materials
To reduce resistance to movement or drag, the oscillating propulsor surfaces
may be coated with
or made out of fluid phobic materials. Examples of materials suitable for
water applications
include polymers, silicon coating, waxes and oils. Advances in nanotechnology
have ushered
the era of superhydrophobic materials with promises of drag reduction in
marine propulsion
applications; coating the oscillating propulsor with these superhydrophobic
materials could
reduce drag and increase efficiency of propulsion.
Embodiments making use of fluid dynamic shape - FIGS. 6 ¨ 8
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A fluid dynamic profile may be provided to the oscillating propulsor (FIG. 6)
by attaching a drag
duction member 640. The drag reduction member 640 may also be built in
integrally to the
oscillating propulsor. For the embodiment disclosed in FIG. 4, the drag
reduction member is
essentially a cone. Aero and hydrodynamic profiles and their characteristics
are known to one
skilled in the art. As illustrated in FIG. 7, oscillating propulsor drag may
also be reduced by
cutting an intake opening 742 across the leading and trailing surfaces of the
spherical body 730.
This embodiment provides the advantage of reduced drag at higher travel speeds
as the incoming
rush of fluid provides a dynamic seal against loss of thrust through forwards
leakage.
As shown in FIG. 8 drag reduction may also be provided by securely connecting
a fore fin 844
to the spherical body 830; the fore fin 844 has a rigid cylindrical head and a
resilient sheet or
mat attached thereto, as shown in FIG. 8. The fore fin 844 is designed to
deflect the frontal
stagnant pressure zone associated with sphere fluid dynamics. A fin installed
on a craft, fore of
the spherical body 30 would function in a similar way, within the constraints
of applicable fluid
dynamics. An aft fm 846, having a rigid cylindrical head and a resilient sheet
or mat attached
thereto, may also be attached to the spherical body 830, as shown in FIG. 8.
The fore fin 844
and the aft fm 846 also provide the advantage of additional thrust,
particularly at low speeds.
Embodiments making use of lubricant cavity - FIGS. 9-11
Cavitation over the oscillating propulsor is anticipated at high oscillation
frequencies and travel
velocity. Alternatively, a lower density fluid or fast moving fluid may be
coated over the
oscillating propulsor's surfaces to reduce drag in the ambient fluids; FIG. 9
shows a sectionned
oscillating propulsor fitted with the actuating member 932 fluidly connected
to a lubricant inlet
948 and a lubricant outlet 950. A pressurized fluid such as air or water is
conveyed, as depicted
by arrows, to lubricant outlet 950 from lubricant inlet 948 and through
actuating member 932.
The pressurized fluid exits lubricant outlet 950 radially to coat the leading
surface of the
spherical body 930 and thus lubricate movement of the apparatus in ambient
fluids. Supply of
pressurized fluid to the lubricant inlet 948 has to allow for the
reciprocating movement of the
oscillating propulsor; this can be achieved, for example, by way of a flexible
hose or moveable
seals. Alternatively the lubricant supply system could be installed in a fixed
position, on a low
drag frame for example, to coat the oscillating propulsor with lubricant. As
shown in FIG. 10
the lubricant cavity may also be provided by way of a double walled pressure
chamber 1052
integrally built to the spherical body 1030. The pressure chamber 1052 is
perforated with at least
one aperture 1034, for delivery of pressurized fluids from the actuating
member 1032 to the
leading surface of the spherical body 1030. FIG. 11 illustrates movement and
delivery of
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pressurized fluid, indicated by arrows, from the actuating member 1132, to the
pressure chamber
1152 and onto the leading surface of the spherical body 1130, through
apertures 1034.
Alternatively the pressurized fluid may be supplied through lubricant outlet
1050, fore of the
spherical body 1030, as shown in FIG. 10; in this embodiment the pressurized
fluid is directed in
a cone shape over the leading surface of the spherical body 1030, as indicated
by arrows. In
embodiments with a drag reduction member 1040, as previously exemplified in
FIG. 6, the
pressurized fluid can be directed over the surface of the drag reduction
member 1040. The
actuating member 32 may also be lubricated similarly, with or without a double
wall pressure
chamber 52.
Promotion of formation of lubricant cavity
The surface of the oscillating propulsor may be configured or constructed to
promote natural
formation of a reduced viscosity boundary layer of the ambient fluid as
provided, for example,
by cavitation phenomena in water; examples of surface construction include
sandblasting,
dimpling and microstructures that reduce surface friction with ambient fluids.
The surface of
golf balls and at least one soccer ball, known as the Jabulani, are engineered
to reduce drag by
means of surface structures like dimples, nibs and ridges. Mechanical
vibrations from the motive
power source could also promote cavitation for drag reduction over the
oscillating propulsor and
attachments thereto. It is anticipated that the oscillating propulsor could
continue to function
under supercavitation conditions because admission and acceleration of a high
speed volume of
fluid before ejection could enable temporary compression of affiliated gases
before ejection of
same in a forceful expansion.
Operation - FIGS. 1, 12-14, 15-19
The apparatus of this disclosure can be operated manually like oars or paddles
with the
additional advantages of reactive propulsion from up and down stroking as well
as swiveling
action. Reciprocating displacements of the apparatus accelerate fluid admitted
therein before
ejecting the same from the trailing concave surface at the end of each stroke.
The ejection of
fluid imparts a reactive propulsive momentum to the oscillating propulsor and
attachments
thereto. Ejection of fluid from the apparatus causes admission of ambient
fluid for the next
stroke and so on as long as the apparatus is oscillated or reciprocated.
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From a static position, thrust may be generated mostly by reaction of the
oscillating propulsor to
the mass and velocity of fluid ejected; as fluid flow over the oscillating
propulsor increases, the
momentum of the fluid may also be transmitted to the oscillating propulsor,
upon fluid
admission. Thus, as displacement or travel speed increases so should thrust
increase; however,
5 the increase in speed is limited by the drag of the oscillating
propulsor. Embodiments with drag
reduction attachments and features, as previously disclosed, can be used to
mitigate this
limitation.
For any given fluid and embodiment of the apparatus, the thrust generated is
influenced mostly
10 by fluid capacity of the oscillating propulsor, oscillation or stroke
frequency, stroke length and
displacement velocity. The apparatus may be attached to a craft to provide
propulsion for travel.
Oscillation of the apparatus can be effected in linear mode, up and down
strokes, as depicted in
FIGS. 1, 12; operation can also be effected in radial mode, side to side or
swivel action, as
shown in the levers of FIGS. 13, 14 and as illustrated further under
industrial applicability. In
these figures, the extreme position of the oscillating propulsor is shown in
phantom lines.
Arrows indicate direction of ejection of fluid from the oscillating propulsor.
Reaction movement
of the oscillating propulsor is in opposite direction to the direction of
fluid ejection. A
reciprocating engine can be coupled directly to the oscillating propulsor;
this would require
connection to the conrod or an extension thereof, eliminating thus the
flywheel, crankshaft and
other components normally associated with a rotary engine. Such a simplified
and lighter engine
could boost efficiency and fitness of the present invention in the propulsion
market.
Alternatively, rotary to reciprocating motion converters can be used with
current motors or
engines to drive the oscillating propulsor. Examples of useable motion
converters include crank
mechanisms and Scotch Yoke devices. Electric, fluid driven and wind mechanical
oscillators
may also be used to drive the oscillating propulsor. For leisure, sports and
in general utility
applications, motive power can be provided by an operator's muscles (FIGS. 16,
19), as further
described below.
6. INDUSTRIAL APPLICABILITY
Fluid pumps, crafts- watercrafts, aircrafts
A general application of the oscillating propulsor is in displacement of
fluids, be it in enclosed
casings as used for pumps or in the open as used for mixing, aeration of
fluids, and ventilation,
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for examples. Attached to a craft, the apparatus can provide propulsion means
for the craft's
displacement, travel or transportation, by wave power or motive power on
board.
Watercrafts
An example of a watercraft propelled by the apparatus is illustrated in FIG.
12. The oscillating
propulsor 1220, driven by motor M reciprocates up and down, taking in water,
accelerating it
and ejecting the same rearwards of the watercraft; this water ejection imparts
a reaction
propulsive momentum to the oscillating propulsor 1220 and the craft to which
it is attached. The
direction of water ejection is shown by the bottom arrows; the craft's
direction of travel is
opposite that of water ejection, as shown by the top wow.
FIG. 13 illustrates an oscillating propulsor fitted with the actuating member
1332 levered about
the fulcrum 1354, for manual or powered operation. The fulcrum 1354 can be
attached to the
craft or device to be propelled. Reciprocating displacements of the lever's
input arm, as shown
by the top arrows, causes reciprocating strokes of the spherical body 1330 at
the output arm;
when reciprocated, the spherical body 1330 admits ambient fluid, accelerating
it and ejecting the
same as depicted by the bottom arrows. Fluid ejection imparts a reaction
propulsive momentum
to the oscillating propulsor and attachments thereto. The oscillating
propulsor and attachments
thereto are urged in a direction opposite that of fluid ejection.
FIG. 14 shows a stylized watercraft fitted with a high mechanical advantage
lever provided by
the actuating member 1432, about the fulcrum 1454. Animation of the
oscillating propulsor 1420
by motor M oscillates the apparatus in swivel mode, as shown in phantom lines.
The oscillating
propulsor 1420 takes in water, accelerates and ejects the same rearwards of
the watercraft, as
indicated by bottom arrows; this water ejection imparts a reaction propulsive
momentum to the
oscillating propulsor 1420 and the craft to which it is attached. Direction of
travel of the craft is
opposite that of water ejection, as shown by the top arrow.
Novel craft concepts, propelled by the oscillating propulsor, are illustrated
in FIGS. 15-19.
Whilst for illustration purposes these embodiments will be described with
reference to
watercrafts and aircrafts, the concepts relate generally to fluids and
fluidized substances and can
be adapted accordingly. In FIG. 15, a buoyant base B is fitted with
oscillating propulsor 1520a at
the front, in a horizontal rearwards thrusting position and similarly fitted
with oscillating
propulsor 1520b at the rear, cooperatively secured to the base B. Motor M1 is
supported on base
B and drives oscillating propulsor 1520c. Motor M2 is rotatably attached to
base B and drives
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oscillating propulsor 1520d, in a vertical position. Upon operation,
oscillating propulsor 1520c
thrusts.water rearwards, along indication arrow, urging the craft forward. The
reciprocating
motion of oscillating propulsor 1520c by motor M1 causes a reactive up and
down motion of the
base B thus animating front and rear oscillating propulsors 1520a and 1520b,
as shown in
phantom lines and thrust indication arrows. Propulsion efficiency is maximized
by using both
the action of and reaction to the reciprocating motive force. Steering and
additional thrust is
provided by oscillating propulsor 1520d, reciprocated by motor M2 in a radial
swivel, as shown
by the arc with two arrows. Alternatively, oscillating propulsor 1520c can be
installed rotatable
to the base B or a conventional rudder can be installed on the craft, for
steering. Recovery of
reaction momentum and its application to propulsion is an advantage of this
embodiment.
The craft disclosed in FIG. 15 could be supported entirely by the oscillating
propulsors to
provide a hydrofoil type watercraft; in that case oscillating propulsors
become propulsive
hydrofoils, adaptable with adjustable thrust angle akin to current hydrofoil
angle adjustment
systems. Alternatively, oscillating propulsors with some buoyancy would
provide a surface
skimming craft. Buoyancy can be provided by coring, as previously described;
in addition, the
fore fin 44 and the aft fin 46 depicted in FIG. 8 could also be made out of
buoyant materials like
hydrophobic polymer sheets and mats.
A muscle-powered or man-powered watercraft propelled by means of the apparatus
is
exemplified in FIG. 16. A buoyant base B is fitted with oscillating propulsor
1620a at the front,
in a horizontal rearwards thrusting position and similarly oscillating
propulsor 1620b at the rear,
cooperatively secured to the base B. At least one pedal 1666 is levered to the
base B through the
fulcrum 1654, to drive oscillating propulsor 1620c donwnward when depressed by
foot, for
example. Oscillating propulsor 1620c is slideably secured to the base by way
of a square sleeve,
embracing to the actuating member 1632. At least one handle 1668, hingedly
connected to the
pedal 1666 can be pulled by hand, for example, to power the upward stroke of
the oscillating
propulsor 1620c. Alternatively, the upward stroke can be returned by a spring
1670, urging the
pedal 1666 upwards. The reciprocating motion of oscillating propulsor 1620c by
pedal 1666 and
handle 1668 causes a reactive up and down motion of the base B, thus animating
front and rear
oscillating propulsors 1620a and 1620b. Operation of the oscillating
propulsors thrusts water, as
indicated by arrows to propel the craft in the opposite direction. Steering
can be effected with a
conventional rudder or by differential thrusting of twinned oscillating
propulsors, as illustrated
in FIG. 16. Propulsion efficiency is maximized by using both the action of and
the reaction to
the reciprocating motive force of the operator. Other actuation systems can be
used to operate
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this embodiment; examples of alternative actuation systems are described in US
pat. No
2,979,018 to Birdsall (1961) and in US pat. No. 3,236,203 to Bramson (1966).
Embodiment with thrust vectoring or directional control - FIGS. 15, 17.
In FIG. 15, motor M2 can swivel about the base B to provide a directed or
vectored thrust from
oscillating propulsor 1520d, as needed, to control the direction of travel of
the craft. A
conventional rudder can also be used to steer the craft. An alternative
embodiment for thrust
vectoring, particularly advantageous where motors are fixed on a craft C, is
shown in FIG. 17.
The actuating member 1732 of oscillating propulsor 1720 is rotatively coupled
to a motion
transmitter 1760 of motor M through an advantageously lightweight, bearing
1756. A control
arm 1758 is cooperatively secured at a first end to the actuating member 1732
and is straddled at
the second end by the U-shaped guide or slot 1762 of a steering member 1764.
The steering
member 1764 is secured to bearing 1756a for advantageous rotation about the
vertical axis of the
actuating member 1732. Bearing 1756a is secured to the craft C and is
slideably engaged to the
actuating member 1732. Alternatively, bearing 1756a can be fixed to the base
of motor M to
provide a propulsion cum steering assembly, detachable from the craft. This
embodiment allows
for rotation or steering of the oscillating propulsor 1720 while oscillating,
as shown in phantom
lines. One or more magnets (not shown) may be attached to the second end of
the control arm
1758, opposite similar pole magnets on the guide 1762; this embodiment
essentially provides a
magnetic bearing that allows operation of the apparatus with reduced
mechanical interference
and associated noises; the control arm 1758 would be centralized in the U-
shaped guide 1762 by
mutual repulsion of the opposing magnets. Other vibration dampening mitigation
systems may
be applied, for example rubber polymers. Steering can be effected by manual
displacement of
the steering member 1764 or by electric means like servo motors. Conventional
steering
devices, for example a steering wheel, can also be coupled to the steering
member 1764. The
thrust vectoring system thus described can be used with embodiments of the
present disclosure,
as required; it can also be used generally for maneuvering and direction
control in other
oscillating systems and as active braking means when thrust is applied against
the direction of
travel to slow down or bring a craft to a halt. The control arm 1758 may be
consolidated with
the lubricant inlet 948 of the embodiment in FIG. 9 to provide a dual purpose
conduit for
lubricant delivery and steering control.
Aircraft
Propulsion of an aircraft could be achieved by mounting and operating the
apparatus on a craft
as illustrated in FIG. 18. The oscillating propulsor 1820 can be installed for
propelling air or can
CA 02821427 2013-07-11
14
be fitted for submerged operation in water, as shown in phantom lines. The
oscillating propulsor
1820 is actuated by motor M to thrust air rearwards as shown by top arrow; for
submerged
operation, shown in phantom lines, water is ejected rearwards, as shown by
bottom arrow, to
propel and lift the craft out of water; the oscillating propulsor remains
submerged while the craft
flies in air. This hybrid aircraft-in-water, propelled by water, provides the
advantage of high
thrust in water with some of the craft's weight supported by water. The lower
drag of the craft
in the air, compared to a similar size watercraft, is another advantage of
this embodiment. The
craft would also benefit from Wing-In-Ground effect, a phenomenon known to
increase
efficiency of lift. The craft of this embodiment could have some autonomy in
full airborne flight
when sufficient speed is attained to leave water and allow momentary flight by
inertia of
movement. Alternatively, both air and water propulsion systems could be
installed and used as
needed to provide a versatile hybrid water and air craft.
FIG. 19 illustrates an embodiment of a muscle or man-powered aircraft
propelled by the
apparatus. At least one lever system, having a pedal 1966 and a handle 1968
input arms, is
secured at the fulcrum to base B through bearing 1956. At least one
oscillating propulsor 1920
is cooperatively connected to the output arm of the lever. Actuation of the
pedal 1966 and the
handle 1968, by foot and hand for example, rocks the oscillating propulsor
1920 in an arc, as
shown by top arrows. Air is thrust downward from the oscillating propulsor
1920 to exert lift on
the craft, as indicated by bottom arrows. Size and number of the oscillating
propulsor 1920,
stroke rate and length would have to be sufficient to lift the total weight of
the craft, including
contents. A twin lever system, as illustrated in FIG. 19 would be advantageous
for balance of a
human operator. A harness for the operator, secured to a safety bracket A,
would be required
(not shown). Harnesses used in parachuting, skydiving and like activities can
be attached to the
craft to secure the operator to the craft.
Whilst the example depicted in FIG. 19 shows direct drive of a plurality of
oscillating
propulsors, it should be understood that indirect drive with stroke rate
multiplication can be
utilized as required to generate the effective thrust for any given
construction of this
embodiment. For example, a leg and foot bicycle type drive system can be
coupled to a Scotch
Yoke mechanism to oscillate the apparatus at the effective stroke length and
frequency.
Other uses
When operated in reverse the apparatus should work as an energy harvester like
propellers do.
CA 02821427 2013-07-11
Since other modifications and changes varied to fit particular operating
requirements and
environments will be apparent to those skilled in the art, the invention is
not considered limited
to the example chosen for purposes of disclosure, and covers all changes and
modifications
which do not constitute departures from the true spirit and scope of this
invention.
5
Having thus described the invention, what is desired to be protected is
presented in the
subsequently appended claims.
10
15
35
CA 02821427 2013-07-11
16
7. List of Reference signs
20 oscillating propulsor
30 spherical body
32 actuating member
34 aperture
36 flat end cap
38 spherical end cap
40 drag reduction member
42 intake opening
44 fore fin
46 aft fin
48 lubricant inlet
50 lubricant outlet
52 pressure chamber
54 fulcrum
56 bearing
58 control arm
60 motion transmitter
62 guide
64 steering member
66 pedal
68 handle
70 spring
30
