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Patent 2371694 Summary

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Claims and Abstract availability

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(12) Patent: (11) CA 2371694
(54) English Title: POWERTRAIN FOR POWER GENERATOR
(54) French Title: ENSEMBLE DE TRANSMISSION POUR GENERATEUR DE COURANT
Status: Deemed expired
Bibliographic Data
(51) International Patent Classification (IPC):
  • H02K 16/00 (2006.01)
  • F04C 29/00 (2006.01)
  • H02K 7/116 (2006.01)
  • H02K 7/18 (2006.01)
  • F03D 11/02 (2006.01)
(72) Inventors :
  • DEHLSEN, JAMES G. P. (United States of America)
  • DEANE, GEOFFREY F. (United States of America)
(73) Owners :
  • CLIPPER WINDPOWER, INC. (Not Available)
(71) Applicants :
  • DEHLSEN ASSOCIATES,L.L.C. (United States of America)
(74) Agent: MARKS & CLERK
(74) Associate agent:
(45) Issued: 2012-01-03
(86) PCT Filing Date: 2000-04-27
(87) Open to Public Inspection: 2000-11-02
Examination requested: 2005-04-07
Availability of licence: N/A
(25) Language of filing: English

Patent Cooperation Treaty (PCT): Yes
(86) PCT Filing Number: PCT/US2000/011303
(87) International Publication Number: WO2000/065708
(85) National Entry: 2001-10-26

(30) Application Priority Data:
Application No. Country/Territory Date
60/131,296 United States of America 1999-04-27
09/552,577 United States of America 2000-04-19

Abstracts

English Abstract




Powertrains for high torque, low RPM wind turbines and ocean current turbines.
The turbine consists of a large, input power shaft-mounted, rotating sun-gear
with stationary powertrains mounted around its periphery. The gear teeth on
the sun gear rotate past the teeth on the pinions, causing the pinions to turn
and delivering power to each smaller powertrain. Alternatively, the
powertrains are attached in a spindle around the perimeter of a main power
input drive shaft, and rotate as the shaft rotates. Each input drive shaft to
smaller powertrain gearboxes is fitted with a pinion. As the main power input
shaft turns, the generators, gearboxes and pinions rotate, moving the pinions
around the interior of a stationary ring gear. Reduction and distribution of
torque is similar to the sun-gear embodiment of the powertrain. In the sun-
gear configuration, each smaller powertrain is stationary, reducing stress
caused by rotation.


French Abstract

L'invention concerne des ensembles de transmission pour turbines de centrales éoliennes et marémotrices à couple élevé et à faible vitesse de rotation. Ce type de turbine comprend une grande roue solaire rotative montée sur un arbre d'entrée, dont la périphérie est équipée d'ensembles de transmission fixes. Les dents d'engrenage de la roue solaire s'engrènent par rotation dans les dents des les pignons, provoquant ainsi leur rotation et transmettant de la puissance à chacun des sous-ensembles de transmission. Dans une variante, les ensembles de transmission, montés sur broche sur tout le pourtour d'un arbre d'entrée principal, tournent en même temps que ledit arbre. Chaque arbre d'entrée reliant les boîtes d'engrenage des sous-ensembles est pourvu d'un pignon. A mesure que l'arbre d'entrée principal tourne, les générateurs, les boîtes d'engrenage et les pignons tournent, provoquant ainsi le déplacement des pignons à l'intérieur d'une couronne dentée fixe. La réduction et la répartition du couple est similaire à celle obtenue dans la variante à roue solaire. Dans ladite configuration en roue solaire, chacun des sous-ensembles de transmission est fixe, ce qui permet de réduire les contraintes causées par la rotation.

Claims

Note: Claims are shown in the official language in which they were submitted.




The embodiments of the invention in which an exclusive property or privilege
is
claimed are defined as follows:


1. An electric power generating device that converts fluid flow of wind or
water to
electricity, comprising:
a rotor having blades that rotate in response to fluid flow;
a main power input shaft coupled to said rotor;
a single-stage torque-dividing gearbox consisting of a gear coupled to said
main power
input shaft and a plurality of pinions having teeth which directly engage
teeth on said
gear; and
a plurality of torque-reducing gearboxes each having an input shaft connected
to one of
said pinions, said plurality of torque-reducing gearboxes being located around
a
perimeter of said main power input shaft.

2. The electric power generating device according to claim 1, wherein the
rotor
revolves in response to said fluid flow; and wherein at least one torque-
reducing gearbox is
included in a sub-powertrain including a generator driven by said torque-
reducing
gearbox.

3. The electric power generating device according to claim 1 or 2, wherein
said
torque-dividing gearbox includes a stationary ring gear having ring gear teeth
around an
inner circumference of said ring gear; wherein each one of said torque-
reducing gearbox
input shafts is connected to one of said plurality of pinions that engages
said ring gear
teeth.

4. The electric power generating device according to claim 1 or 2, wherein
said
torque-dividing gearbox includes a stationary sun gear, about which said
plurality of
torque reducing gearboxes rotate.

5. The electric power generating device according to claim 1 or 2, wherein
said
plurality of torque-reducing gearboxes are stationary and said torque-dividing
gearbox
includes a driving gear having teeth, each one of said torque-reducing gearbox
input
shafts being connected to a gear that engages the teeth of said driving gear.





6. The electric power generating device according to claim 1 or 2, wherein
said
plurality of torque-reducing gearboxes are stationary and said torque-dividing
gearbox
includes a ring gear which rotates around said perimeter of said main power
input shaft.
7. The electric power generating device according to claim 3, wherein, as said
main
power input shaft turns, said torque-reducing gearboxes and said gears
connected to the
torque-reducing gearbox input shafts rotate with said main power input shaft.

8. The electric power generating device according to claim 5, wherein, as said
main
power input shaft turns, said driving gear rotates, causing said gears
connected to the
torque-reducing gearbox input shafts to turn, and driving said torque-reducing
gearboxes.
9. The electric power generating device according to claim 3 or 7, wherein
said
plurality of torque-reducing gearboxes are connected by a spindle to said main
power
input shaft such that as said main power input shaft turns, said spindle
rotates.

10. The electric power generating device according to any one of claims 3, 7
or 9,
wherein said torque-dividing gearbox is housed in a nacelle and said ring gear
is fixed
around an inner perimeter of said nacelle.

11. The electric power generating device according to claim 5 or 8, wherein
said
torque-dividing gearbox is housed in a nacelle that provides a portion of a
structural
casing for said driving gear.

12. The electric power generating device according to any one of claims 1 to
11,
wherein the torque-reducing gearboxes have a torque reducing ratio different
from 1:1.
13. The electric power generating device according to any one of claims 2 to
12,
wherein at least one torque-reducing gearbox of the sub-powertrain is coupled
in series
between a torque-dividing gearbox output shaft and the generator.


11

Description

Note: Descriptions are shown in the official language in which they were submitted.



CA 02371694 2009-10-22

POWERTRAIN FOR POWER GENERATOR
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to electric power-generating devices such as wind
turbines
and ocean current turbines, and more particularly to a method and apparatus
for
distributing to various gearboxes the input torque characteristic of low
rotational velocity
high-torque operation of wind or water turbine blades.

BACKGROUND
Many electric power-generating devices, such as wind turbines and ocean
current
turbines, benefit from economies of scale, yielding lower costs for generated
electricity
with larger power generation per unit- This increase in power is often
accompanied by a
reduction in rotational velocity of the power input shaft, resulting in a
large increase in
torque. Because electric generators require rotational velocities tens to
hundreds of times
greater than the rotational velocity of the input shaft, a speed increasing
gearbox is often
applied between the power input shaft and the generator. Generally, torque (z)
delivered
by the power input shaft to the speed-increasing gearbox for such applications
is given by

P/w (1)
where P is the power and co is the rotational velocity of the power input
shaft. Costs of
conventional gearboxes (planetary, helical, etc.) increase exponentially with
increased
torque, diminishing the beneficial effects of increased scale. In addition,
such high torque
gearboxes must generally be custom designed and manufactured for specific
application,
further increasing their costs.

It is desirable to provide a way of reducing the torque on gearboxes resulting
from
slow moving turbine blades.

1


CA 02371694 2007-06-27

Prior art shows several inventions with multiple motors driving a single power
output shaft, an application significantly different than the present
application. Electric
generating systems have been shown in the art to use multiple generators
powered by a
single gearbox. In each invention, the division of this power generating
capacity to the
multiple generators is done for power quality considerations. Division of
gearboxes is
becoming rare in recent commercial applications, largely because the cost of
many small
generators often exceeds the cost of a single large generator with the same
capacity.

In addition, as turbines grow in size, the size and weight of individual
components
grow as well. Wind turbines place these components on top of a tower,
presently
stretching to over 60m above the ground, while ocean current turbines are
located at sea,'
where they can only be accessed by boat. The size of the components
necessitates very,
large lifting equipment, making both the land-based cranes and ocean lifting
equipment
extremely costly. It is desirable to provide a way of reducing the weight and
size of
individual components of electricity generating equipment.

By dividing the powertrain into smaller components, generating systems receive
an element of redundancy. For example, when ten small gearboxes and generators
split
the system's load, if one gearbox or generator experiences a fault, the
system's capacity
may only be reduced by 10%, allowing the system to remain active. A single set
of
components loses all of its capacity when a single component experiences a
fault. It is
desirable to provide a way of establishing reliability through redundancy in
generating
systems.

SUMMARY OF THE INVENTION
Briefly, in accordance with the invention, an electric power-generating device
comprises a rotor which revolves in response to an external source of
mechanical energy
to which is coupled a main power input shaft. A torque-dividing gearbox is
coupled to the
main power input shaft and a plurality of torque-reducing gearboxes, each
driving a
generator and each having an input shaft, are connected to the torque-dividing
gearbox.
The plurality of torque-reducing gearboxes are located around a perimeter of
the main
power input drive shaft.

2


CA 02371694 2008-07-03

In accordance with an embodiment of the present invention, a powertrain for
wind turbines and ocean current turbines consists of a large, input power
shaft-mounted,
rotating driving-gear, or sun gear with stationary smaller powertrains mounted
around its
periphery. The gear teeth on the sun gear rotate past the teeth on the
pinions, causing the
pinions to turn and deliver power to each smaller powertrain. Alternatively,
powertrains
are attached in a spindle around the perimeter of a main power input drive
shaft, and
rotate as the shaft rotates. The input drive shaft to each of the smaller
powertrain
gearboxes is fitted with a pinion. As the main power input shaft turns, the
generators,
gearboxes and pinions rotate, moving the pinions around the interior of a
stationary ring
gear. Reduction and distribution of torque is similar to the rotating sun-gear
powertrain.
In the sun-gear configuration, each smaller powertrain is stationary, reducing
stress
caused by rotation.
Another embodiment of the present invention provides an electric power
generating device that converts fluid flow of wind or water to electricity,
comprising:
a rotor having blades that rotate in response to fluid flow;
a main power input shaft coupled to said rotor;
a single-stage torque-dividing gearbox consisting of a gear coupled to said
main power
input shaft and a plurality of pinions having teeth which directly engage
teeth on said
gear; and
a plurality of torque-reducing gearboxes each having an input shaft connected
to one of
said pinions, said plurality of torque-reducing gearboxes being located around
a
perimeter of said main power input shaft.
Another embodiment of the present invention provides an electric power-
generating device that converts fluid flow of wind or water to electricity
comprising:
a rotor having blades that rotate in response to fluid flow;
a main power input shaft coupled to said rotor;
a single-stage torque-dividing gearbox coupled to said main power input shaft;
said
torque-dividing gearbox having a plurality of output shafts located around a
perimeter of
said main power input shaft; and
a plurality of sub-powertrains, each one of said sub-powertrains including a
generator
coupled to a respective one of said torque-dividing gearbox output shafts;
wherein at
least one of said sub-powertrains includes a torque-reducing gearbox coupled
in series
between a torque-dividing gearbox output shaft and a generator.

3


CA 02371694 2008-07-03

Yet another embodiment of the present invention provides an electric power-
generating device that converts fluid flow of wind or water to electricity
comprising:
a rotor having blades that rotate in response to fluid flow;
a main power input shaft coupled to said rotor;
a single-stage torque-dividing gearbox coupled to said main power input shaft;
and
a plurality of sub-powertrains, each including a generator having an input
shaft
connected to said torque-dividing gearbox, said plurality of sub-powertrains
being
located around a perimeter of said main power input shaft; wherein at least
one of said
sub-powertrains includes a torque-reducing gearbox driving a generator.

BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described in detail with reference to the drawings in
which:
FIGURE 1 is a cut-away view of a preferred embodiment of the distributed
powertrain of the invention;
FIGURE 2 is a close-up view of the components of the preferred embodiment
shown in FIGURE 1;
FIGURE 3 is an isometric view of the preferred embodiment shown in FIGURE
1;
FIGURE 4 shows a side view of a single sub-powertrain in an alternate
embodiment of the invention;
FIGURE 5 is a schematic diagram of prior art US Patent 4,691,119, illustrating
the placement of a torque-splitting mechanism relative to a reducer;
FIGURE 6 is a schematic diagram of the present invention for comparison with
FIGURE 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGURE 1 is a cut-away view of the preferred embodiment of the distributed
powertrain. Power, supplied by the flow-driven rotation of the rotors, is
transmitted into
the nacelle by the rotating main shaft 10. A torque-dividing gearbox,
comprising a sun
gear 20, pressure-mounted on the perimeter of the main shaft and rotating with
the shaft,
interacts with five pinions 30 mounted around its perimeter, causing them to
turn at a
rotational rate greater than that of the sun-gear. The chamber 40 in which the
sun-gear
and pinions rotate is flooded with oil or contains an oil distribution system
for

3a


CA 02371694 2007-06-27

lubrication. Each pinion is coupled-to the input end of a small torque-
reducing gearbox,
which increases the rotational speed of the output shaft relative to the
pinion. The output
shaft of each gearbox is connected by a coupling 60 to a generator 70. Each
sub-
powertrain consisting of a gearbox 50 and generator 70 is mounted to a
circular plate 100
comprising one wall of the oil-filled pinion chamber 40. Each gearbox 50 is
held within a
plate-mounted gearbox flange 110, to which is mounted a generator flange 120.
The
generator 70 is then mounted to the generator flange 120. The smaller size of
the sub-
powertrains relative to conventional larger powertrains allows for easy
component
handling through a nacelle hatch 130.

FIGURE 2 is a close-up view of the components of the preferred embodiment
shown in Figure 1. A seal 200 prevents water leakage, in the case of a current
turbine, or
fouling, in the case of a wind turbine, of the roller bearings 210 supporting
and allowing
rotation of the main shaft. The pinions are held in place by bearings 230,
240. Gussets
220, 250 in the nacelle structure support the loads transferred from the main
shaft to the
bearings.

FIGURE 3 is an isometric view of the preferred embodiment shown in Figure 1.
This view more clearly illustrates the interaction between the sun-gear 20 and
the pinions
30 within the oil-filled chamber 40. The generator, generator flange 110, and
gearbox
flange 120 are seen to be mounted to the circular plate 100. The pinion
bearings 230 are
mounted to the walls of the oil-filled chamber 40, which is fortified by
structural gussets
250.

FIGURE 4 shows the side view of a single sub-powertrain in an alternate
embodiment of the present invention in which each of the sub-powertrains is
mounted on
a cylinder 300 that is mounted on the main shaft 310. A torque-dividing
gearbox, ring
gear 320, is fixed around the inner perimeter of the nacelle. Each of the sub-
powertrains
is joined via a coupling 370 to a pinion 330. Fluid motion causes the rotors
to turn,
turning the main shaft and the sub-powertrains mounted to the main shaft. As
the sub-
powertrain

4


CA 02371694 2007-06-27

spindle rotates, the pinions move past the ring gear within an oil-filled
chamber 340,
causing the pinions to rotate faster than the main shaft and supplying input
power to the
sub-powertrains' gearboxes 350. Each gearbox serves to increase the rotational
speed of
its output shaft relative to its input shaft. The gearbox output shaft is then
joined by a
coupling 380 to a generator 360. Conduits carrying electricity generated by
the sub-
powertrains' generators are gathered within the main shaft and transferred to
a non-
rotating conductor via a slip-ring 390.

The present invention via a torque-dividing gearbox distributes a high input
torque of the rotor 116 between multiple powertrains, each consisting of a
smaller
conventional torque-reducing gearbox 200 and generator 202. The sum of the
power
producing capacities of the generators is equal to the maximum power delivered
by the
power input shaft, and is equivalent to the power produced by a single
generator in a
conventional system.

If the spindle consists of a number, n, of smaller powertrains, and the gear
ratio
between the ring gear and the pinion is m, then the torque, z', delivered to
each of the
gearboxes is given by

z'=(P/n)/mw
(2)

where P is the total system input power and co is the rotational velocity of
the spindle. It
can bee seen that the gearbox input torque, as given in Eq. 1, is reduced by a
factor of (m
x n)-'. In a system consisting of 6 powertrains, with a ring to pinion gear
ratio of 15,
torque delivered to each gearbox is reduced to 1.1 1% (1/90'h) of the torque
of the power
input shaft alone.

FIGURE 5 is a schematic diagram illustrating prior art (US Patent 4,691,119).
This invention couples multiple generators 430 coupled 428 to shafts 426
having pinions
425 around a high-speed (low torque) sun gear 420 within the gearbox's second
stage.
The principal function of this invention is to "create an efficient power
supply with a



CA 02371694 2007-06-27

controllable output frequency" to improve the quality of generated electricity
for use in
avionics. The power input is at high RPM, greatly reducing the need for first
stage 410
step-up and torque reduction, and therefore reducing the loads applied to the
gearbox. A
somewhat similar design is used in the invention shown in US Patent 4,585,950,
wherein
multiple generators are coupled to the high-speed shaft 415 of a wind turbine
gearbox for
power quality reasons.

Both of the above prior art designs split the input power at the high-speed
end of
the gearbox 415, where the input torque applied to each pinion or belt drive
is greatly
reduced. Instead, the driving shaft upon which the sun gear or belt drive is
located could
be simply attached to an external gearbox stage or to a single generator.
Present
understanding of gearbox and generator pricing teaches that high input speed
gearboxes
are relatively inexpensive, and that multiple generators cost more than a
single large
generator. In addition, power electronics have been developed to for the
functions for
which the above inventions have been designed. Therefore, present teaching
leads away
from use of multiple generators divided at the low-speed shaft of a multi-
stage gearbox.

In comparison, FIGURE 6 is a schematic diagram of the present invention, which
first divides the input torque at the low speed shaft 500 by turning pinions
502 around an
input shaft-mounted sun gear 501 before translating it through shafts 504 and
couplings
506 into multiple independent smaller gearboxes 510, which are then coupled
516 via a
shaft 514 to small generators 520. The sun gear 510 and pinions '502 form an
effective
first stage to the gearbox, while each of the sub-powertrains' gearboxes 510
are self-
contained second stages. The first stage need not be a torque-reducing stage.
Instead, it
may serve as only a torque-splitter, dividing the load between the separate
pinions and
distributing the contact load between the teeth on the pinions. The diameter
of the sun
gear could be the same as the diameter of each pinion, resulting in more of
the torque
reduction occurring in the individual second stages. The ability to limit the
step-up
required in the first stage while still resulting in dramatically reduced
torque delivered to
the second stage results in significant material and associated cost savings.

6


CA 02371694 2007-06-27

This invention offers a number of solutions not native to conventional
powertrains
having a single gearbox and generator:

1. The high torque is split between multiple gearboxes, with the input speed
to
each benefiting from the 5 to 20:1 step up between the ring gear and the
pinions. This enables each of the powertrains to consist of commercially
available components, with much higher gearbox input speed. This higher
input speed and lower power per powertrain results in greatly reduced input
torque- The summed cost of these higher speed, lower torque gearboxes is
significantly less than the cost of a single low speed, high torque gearbox.
In
addition, the summed weight of these smaller gearboxes is significantly less
than the weight of a single low speed, high torque gearbox.
2. The parallel powertrains in each nacelle offer an aspect of redundancy that
would not be present with a single powertrain, eliminating the single point
failure of an individual gearbox and generator. Should one powertrain suffer a
fault, it may be taken off line, and the device may continue to generate
electricity at a reduced capacity until maintenance is possible.
3. Efficiency may be boosted by taking powertrains off line when they are not
required in lower input power periods. Because generators typically suffer
.greater efficiency reductions when operating below nominal power input,
taking several powertrains off line may allow the remaining powertrains to
operate nearer to their optimal efficiency. For instance, if a 750 kW turbine
consisted of ten 75 kW systems, then two systems (opposite each other in the
ring of powertrains for load balancing) could be taken off line when power
production dips below 80%, allowing the remaining generating systems to
remain nearer optimal generating efficiency. Typical efficiency gains may be
from I to 5%, or 20 to 80% reduction in generator losses.
4. Generator and gearbox cooling may benefit from the reduced mass of
individual components and from the spacing of components yielding
additional air circulation.

7


CA 02371694 2007-06-27

5. Many of the smaller generating systems available are robustly designed and
have very strong performance records, which may help to reduce powertrain
faults and expensive maintenance time.
6. Each powertrain is significantly less massive than a single large
powertrain,
and may therefore be handled more easily. A significant portion of O&M
costs for wind and current turbines come from rental of heavy lifting
equipment such as cranes. Because the size of individual components is
reduced, the size of the required equipment and the associated costs may be
reduced.
7. Access for maintenance, removal, or replacement is facilitated by the
revolving spindle of powertrains. The spindle may be rotated a fraction of a
revolution, exposing each powertrain to a single access hatch in the device
casing.
8. The main sun or ring gear and the pinions may be installed to rotate in
either
direction. This allows for manufacturing and grinding of one set of gearing
regardless of the direction of rotation of the main shaft. For some
applications
it may be advantageous for turbines to rotate in one direction or the other.
Because conventional gearboxes are typically designed to rotate in one
direction only, two separately designed and manufactured gearboxes would
otherwise be required to allow selection of operating direction.
9. The present invention may be used in conjunction with a fixed pitch,
variable
speed wind turbine concept. Torque control on the generator may be
combined with power electronics to modulate speed. To apply this
successfully, a low contact stress gearbox design, such as the present
invention, is required in order to handle the associated load excursions.
10. The present invention may allow maximizing of aerodynamic efficiency in
wind turbines. Given the high gear ratios achievable with the present
invention in a relatively light and compact configuration, the wind turbine
rotor can be operated at lower rotational speeds, which allows for reduction
in
the blades' tip speed ratio. Operating at a reduced tip speed ratio allows for
reduction in blade noise, for reduction in blade surface erosion, and for
increases in aerodynamic efficiency due to reduced drag and tip losses.

8


CA 02371694 2007-06-27

While the invention has been particularly shown and described with reference
to
preferred embodiments thereof, it will be understood by those skilled in the
art that the
foregoing and other changes in form and detail may be made therein without
departing
from the scope of the invention.

All of the numerical and quantitative measurements set forth in this
application
(including in the claims) are approximations. The invention illustratively
disclosed
herein suitably may be practiced in the absence of any element which is not
specifically
disclosed herein.

9

Representative Drawing
A single figure which represents the drawing illustrating the invention.
Administrative Status

For a clearer understanding of the status of the application/patent presented on this page, the site Disclaimer , as well as the definitions for Patent , Administrative Status , Maintenance Fee  and Payment History  should be consulted.

Administrative Status

Title Date
Forecasted Issue Date 2012-01-03
(86) PCT Filing Date 2000-04-27
(87) PCT Publication Date 2000-11-02
(85) National Entry 2001-10-26
Examination Requested 2005-04-07
(45) Issued 2012-01-03
Deemed Expired 2014-04-29

Abandonment History

Abandonment Date Reason Reinstatement Date
2004-04-27 FAILURE TO PAY APPLICATION MAINTENANCE FEE 2004-05-05

Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Application Fee $300.00 2001-10-26
Maintenance Fee - Application - New Act 2 2002-04-29 $100.00 2001-10-26
Registration of a document - section 124 $100.00 2002-08-06
Maintenance Fee - Application - New Act 3 2003-04-28 $100.00 2003-03-19
Reinstatement: Failure to Pay Application Maintenance Fees $200.00 2004-05-05
Maintenance Fee - Application - New Act 4 2004-04-27 $100.00 2004-05-05
Request for Examination $800.00 2005-04-07
Maintenance Fee - Application - New Act 5 2005-04-27 $200.00 2005-04-11
Maintenance Fee - Application - New Act 6 2006-04-27 $200.00 2006-04-10
Maintenance Fee - Application - New Act 7 2007-04-27 $200.00 2007-04-04
Maintenance Fee - Application - New Act 8 2008-04-28 $200.00 2008-04-01
Registration of a document - section 124 $100.00 2008-05-06
Registration of a document - section 124 $100.00 2008-07-25
Registration of a document - section 124 $100.00 2008-07-30
Maintenance Fee - Application - New Act 9 2009-04-27 $200.00 2009-03-09
Maintenance Fee - Application - New Act 10 2010-04-27 $250.00 2010-02-25
Registration of a document - section 124 $100.00 2010-05-10
Maintenance Fee - Application - New Act 11 2011-04-27 $250.00 2011-03-03
Final Fee $300.00 2011-10-12
Maintenance Fee - Patent - New Act 12 2012-04-27 $250.00 2012-04-19
Owners on Record

Note: Records showing the ownership history in alphabetical order.

Current Owners on Record
CLIPPER WINDPOWER, INC.
Past Owners on Record
CLIPPER WINDPOWER TECHNOLOGY, INC.
DEANE, GEOFFREY F.
DEHLSEN ASSOCIATES,L.L.C.
DEHLSEN, JAMES G. P.
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.
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Document
Description 
Date
(yyyy-mm-dd) 
Number of pages   Size of Image (KB) 
Abstract 2001-10-26 1 71
Representative Drawing 2002-04-17 1 17
Claims 2001-10-26 3 91
Drawings 2001-10-26 5 96
Description 2001-10-26 9 407
Cover Page 2002-04-18 1 54
Description 2007-06-27 10 421
Claims 2007-06-27 4 154
Description 2008-07-03 10 437
Claims 2008-07-03 2 89
Description 2009-10-22 10 437
Claims 2009-10-22 2 86
Representative Drawing 2011-11-28 1 18
Cover Page 2011-11-28 2 61
Prosecution-Amendment 2006-04-19 1 28
Prosecution-Amendment 2006-04-19 1 28
Assignment 2008-10-23 2 70
PCT 2001-10-26 8 367
Assignment 2001-10-26 2 107
Correspondence 2002-04-12 1 30
Assignment 2002-08-06 5 285
Prosecution-Amendment 2005-04-07 1 44
Prosecution-Amendment 2006-12-27 3 99
Prosecution-Amendment 2007-06-27 20 857
Prosecution-Amendment 2008-01-03 3 110
Assignment 2008-05-06 15 607
Prosecution-Amendment 2008-07-03 9 414
Assignment 2008-07-25 5 257
Assignment 2008-07-30 2 84
Correspondence 2008-08-11 1 23
Prosecution-Amendment 2009-04-22 2 75
Prosecution-Amendment 2009-10-22 7 285
Assignment 2010-05-10 16 365
Prosecution-Amendment 2010-06-11 1 33
Correspondence 2011-10-12 1 32