Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
The present invention relates to a windmill structure and
more particularly to a windmill used primarily for converting wind
energy to mechanical and/or electrical energy.
The wind energy has hardly been utilized effectively
nowadays although the same is one of the greatest source of energy
obtainable on the earth. This is due to the fact that it is quite difficult
to utilize the wind energy mainly because the wind changes so often both
in wind direction and wind velocity. It is apparant that the wind con-
tributes to a mankind as a clean and indefinite energy source if it could
be effectively converted to other energies such as an electrical power.
In order to utilize a wind energy as a stable energy source,
it is material to provide a windmill power generator device, which con-
verts the wind energy to a mechanical or rotational energy and then to
an electrical energy, and a device for storing the thus obtained electri-
cal energy. One of the greatest problems inherent to the windmill power
generation is a structure of a windmill, because an output of a wind-
mill varies in a square ratio of an diameter oP sails, or wind-engaging
blades, of the windmill and in a cubic ratio of the wind velocity. Thus,
the windmill which is constructed for the purpose of utilizing a general
wind velocity of about 4-5 m/sec. will generate a hundred times of the
output in case of the strong wind such as a typhoon or the like . On the
other hand, a windmill manufactured solid enough to withstand a strong
wind will hardly operate in a general case of the wind velocity of about
4-5 m/sec. or less.
An attenpt has been made to solve these probelms by pro-
viding a windmill in which a pitch or twist of the sails is varied in
accordanced with a wind pressure received by the sails of the windmill.
However, such a adjustable pitch type windmill is extraordinarily
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complex in structure, and therefore it does not meet with
economic requirements. Further, it is likely that the sails are
broken or damaged due to a "flutter" which is a vibration
generated at a change of the wind direction.
SU~r~ARY OF THE INVENTION
Accordingly, the present invention provides a windmill
structure comprising: a vertically extending tower; a horizontal
structure rotatably supported on an upper portion of said tower
; and extending transversely thereof so that said horizontal
structure is rotatable about an axis of said tower in accordance
with a change of wind direction; pivot members having horizontal
axes connected to said horizontal member at predetermined
positions thereof so that said horizontal member is balanced
with respect to the axis of said tower, said pivot members having
lower portions positioned below the axes and upper portions
positioned above the axes; electric generators mounted to the
lower portions of each of said pivot members; sails rotationally
connected to each of said electric generators; and weight members
connected to upper portions of each of said pivot members, said
weight members being mounted opposite to said sails relative to
vertical planes which pass through the axes of said pivot members.
The applicant has arrived, after trials and errors for
more than 40 years, at a conclusion that a windmill should have
a structure
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so that a constant wind pressure is received by sails of the wind-
mill regardless of the wind velocity. The present invention is
; based upon the above viewpoint and has been completed.
The windmill of the present invention is simple in
struct;ure, and the applicant believe that simplicity is the soul
of the windmill. One of the most difficult problems to be solved
in the field of a wind energy utilization system is an economic
aspect. In order to obtain the same output from a windmill as
from a watermill, the windmill should be about 800 times larger
than the size of the watermill since an air density is about 1/800
of a water density. Accordingly, a special attention should be
taken to a windmill structure so that a minimum manufacturing
material may be able to provide a maximum effect of the wind
energy.
Other objects and features of the present invention
will become apparent from the detailed description of preferred
embodiments thereof, which will be read with the accompanying
drawings.
DESCRIPTION OF THE DRAWINGS
Fig. 1 is a perspective view of a windmill structure
' helpful in understanding the present invention;
Figs. 2A, 2B, and 2C are side views of a principal por-
tion of the windmill, showing that a combined structure of an
electrical generator device and sails is pivoted in accordance
with the wind velocity;
-~ Figs. 3A and;3B which appear on the same sheet as Fig.
1, are circuit diagrams applicable to the windmill structure of
the invention;
Fig. 4 is a perspective view of a windmill structure
in accordance with an embodiment of the present invention; and
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Figs. 5 and 6 are explanatory side views of a principal
portion of the windmill shown in Fig. 4 (Fig. 5 appears on the
same sheet as Figs. 2A, 2B, 2C).
DETAILED DESCRIPTION OF THE PREFERRED EMBODI~IENTS
Referring first to Fig. 1 which shows a simplified
structure of the windmill of the present invention, a tower 1
is constructed in such a manner as illustrated. Extending
vertically upwardly from the tower 1 is a tubular shaft 2 from
which extends rotatably a rotating collar 3. Extending hori-
zontally from the collar is a T-shaped body 4 which is designed
in a skeletal manner and has a tail body 6. Connected to
opposite sides of the collar 3 are arms 5a, 5b which extend sub-
stantially horizontally from the collar 3. Thus, arms 5a, 5b
are rotatable together with collar 3 about an axis of the
tubular shaft 2. The tail body 6 is connected to the collar
3 and to the arms 5a, 5b such that the tail body 6 extends from
the collar 3 with right angles to the lengthwise direction of
the arms, as illustrated. The tail body 6 has a vertical planar
vane 7 at the end thereof, which is disposed so as to capture
wind and rotates the collar 3, thereby rotates the posision
of the windmill and allows an immediate pivotal movement of the
arms 5a, 5b about the tubular shaft in accordance with the
direction of the wind.
At the end of the arms 5a, 5b which is indicated by
reference numeral 8a and 8b, are swingably or pivotably disposed
members which are referred to as pivot members 9a, 9b. The pivot
members 9a, 9b are connected to electrical generator devices 10a,
10b respectively, so that the electrical generator devices are
firmly secured to the pivot members 9a, 9b. The electrical gen-
erator devices 10a, 10b will not be described in detail since theknown devices can be utilized. Connected to rotary shafts lla,
llb of the electrical generator devices 10a, 10b are sails12a,
12b which are formed like an airplane propeller
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as illustrated. Thus, the combined structure of the sails 12a, 12b
and the electrical generator devices 10a, 10b are swin~ably or pivotally
connected to the ends of the arms 5a, 5b so that the combined structure
i9 pivoted in the rearward direction. In the illustrated embodiment
the number of sails is two, but it will be understood that any suitable
number of sails may be utilized. Furthermore, the illustrated embodi-
ment shows the sails as being substantially airplane propeller shaped,
but other configurations may be utilized without departing from the
spirit and scope of the invention.
Extending rearwardlyhorizontally from the end portions 8a,
8b of the arms 5a, 5b are members 13a, 13b which have guide rings
14a, 14b at the ends thereof. Guide members 16a, 16b, which are in
the shape of a quarter circular arc and have hooks or stoppers 15a, 15b
at the ends thereof, are extended from the pivot members 9a, 9b.
The g-uide members 16a, 16b are slidably held by the guide rings 14a,
14b of the members 13a, 13b so that the guide members may move
through the guide rings 14a, 14b. The circular arc shaped guide mem-
bers 16a, 16b in the illustrated embodiment are quadrant arcs. Thus,
a pivotal or swinging movement of the electrical generator devices 10a,
10b with the sails 12a, 12b is limited to an extent of about 90, that
is from the position of Fig. 2A to the position of Fig. 2C. However,
the elements for limiting the swinging movement is not prerequisite to
the present invention. Outputs of the electrical generator devices are
obtained through lead wires (not shown) which are disposed along the
arms 5a, 5b and within the tubular shaft 2 for connection to any suitable
electrical utilization source such as a battery to be charged. The
electrical generator devices 10a, 10b are electrically connected whether
in series or parellel as shown in Figs. 3A and 3B in accordance with
various requirements/conditions of electrical generation of the wind-
mill. Further, a gear box ~not shown) may be provided between the
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sails 12a, 12b and the generator devices 10a,10b.
An operation of the windmill structure shown in Fig. 1 is
described with reference to Figs. 1, 2A, 2B and 2C. When the wind
ric~es, the T-shaped body 4 is horizontally rotated or povoted about
the tubular shaft 2 by an effect of the vane 7 so that the sails 12a, 12b
face against, or encounter, the wind. The sails 12a, 12b, which are
connected to the electric generator devices 10a, 10b through the rotary
shafts 11a, 11b, are rotated adainst the wind direction in case of a
weak wind or breaze, as illustrated in Fig. 2A. In case that the wind
is stronger, the combined structure of the sails 12a, 12b and the gener-
ator devices 10a, 10b is pivoted rearwardly by the wind as illustrated
in Fig. 2B, and a rotation of the sails is maintained at the position
where the wind pressure is balanced with the weight of the combined
structure of sails and generator devices. In a case that the wind is
much stronger such as gale or storm, the position of the combined
structure of sails 12a, 12b and generator devices 10a, 10b isfurther
shifted upwardly from the position of Fi8. 2B to a position where the
sails are rotated with the rotary shafts being vertical as illustrated
in Fig. 2C while the sails are being rotated. Thus, the area of the
sails 12a, 12b which receive the wind is increased or decreased
automatically in accordance with the wind velocity, and receives sub-
stantially a constant wind pressure. Therefore, the rotation of the
sails are maintained as being constant.
Since the axis of the pivotal movement of the combined stru-
cture i5 positioned above the pivot members 9a, 9b, the electrical
generator devices 10a, 10b are not affected by a reaction of gyromoment
induced by the rotation of the sails 12a, 12b. This structure allows
prevention of damage or break at the rotary shafts of the electrical
generator devices. Further, the structure in which two sails and
generator devices are pivotally suspended in a symmetrical relation
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allows an economical manufacture of the tower 1. In addition, the
wind pressure received by the pivotable sails is maintained constant
regardless of the wind velocity, and therefore simple structure of the
tower can be utilized. Furthermore, since the T- shaped body 4 is
pivoted immediately about the collar 3 when the wind shifts to another
direction, fluttering due to a reaction of gyromoment in case of a change
of the wind direction can be prevented.
It may be possible to remove the tail body 6 and the planar
vane 7 because a moment of force is naturally produced and affected
to the arms 5a, 5b to urge the sails 12a, 12b to face against the wind
direction. However, it was found that the vane 7 facilitated an immed-
iate pivotal movement of the T- shaped body 4 particularly at the initial
stage of the wind blowing.
Referrin8 now to Fig. 4 which shows another embodiment of
the present invention, a T-shaped body which is generally indicated at
24 is rotatably engaged, by means of a collar 23, with a tubular shaft
22 which is tightly secured in a vertical posture by a tower (not illus-
trated). The T-shaped body 24 comprises arms 25a, 25b and a tail
body 26 having a vane 27. The T- shaped body 24 may be replaced by
the T- shaped body 4 of the first embodiment shown in Fig. 1, or may
be designed to any other configurations. On top of the collar 23 is
provided a protrusion 33 for reinforcing and maintaing the balanced and
horizontal position of the arms 25a, 25b by means of a reinforcing mem-
ber 34.
The vane 27 has two panels symmetrically disposed at the
rear end portion of the tail body 26. The vane is pivotally connected
with the tail body 26, which is formed in the shape of a bar in this
embodiment, by means of a bearing device (not shown) at the upper por-
tion of the vane 27. The applicant has found it desirable to form the
two panels curved outwardly at the rear end thereof as illustrated.
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.This structure has proved that less fluttering was produced when the
wind direction changed and that the structure facilitated an immediate
pivotal or rotational movement when the wind direction changed. The
vane 27 is pivotable and permits an immediate directional change of
the T-shaped body 24, namely a rotation about the tubular shaft 22,
even when there undergoes an abrupt and sudden change of the wind
direction, because the vane 27 receives a violent sidewise or whirl
wind and immediatelu pivots about the axis of the tail body 26 tow rd
a horizontal position illustrated by phantom lines in Fig. 4 to avoid
the full and direct pressure of the violent sidewise or whirl wind and
then retracts to the original vertical posture. Therefore, the pivotable
structure of the vane 27 facilitates an immediate and smooth directional
;change of the windmill.
Pivotal members 29a, 29b in this embodiment are formed in
the shape of a plate in a U-shape whereas the first embodiment of Fig. 1
shows skeletal design. The pivot members are pivotally connected to
the ends 28a, 28b of the arms 25a, 25b. Electrical generator devices
30a, 30b which have sails 32a, 32b are connected to the lower end of the
pivotal members 29a, 29b, and counter balance weights 42a, 42b are con-
nected to the upper portion of the pivotal members, respectively. The
counterbalance weights are disposed at the rearward position with
respect to the axis (28a, 28b) of the pivotal members 29a, 29b. The
position of the counter balance weights 42a, 42b is adjusted by means
of screws (not shown) and adjustment plates 41a, 41b each having a plu-
rality of holes for securing the counter balance weights. Provision
of the balancing weights is based upon the finding that the counter
balance weights permit an immediate rotation, namely rotary shift, of
; the pivotal members between 30 and 90 , which are angular degrees
from the initial stage of the operation, when the wind becomes stronger
but not so strong as a gale or storm. In other words, it was found
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that the pivotal members 29a, 29b do not move any further beyond
the position of about 30 to an extent of 90 until an extraordinarily
strong wind blows. Thus, it is not likely that a stable output can be
obtained particularly when the wind velocity is of an order of inter-
mediate scale, for example, 10-15 m/sec.
The adjustable counter balance weights 29a, 29b, which
are adjustably positioned at the rearward position with respect to
the axis of the pivotal members 29a, 29b, allow substantially a con-
stant electrical generation because the combined structure of elec-
trical generator devices 30a, 30b and sails 32a, 32b can be shifted
to a suitable position in accordance with the wind velocity. To be
more specific, when the sails 32a, 32b are in the position within about
30 from the position of normal or windless condition as illustrated
by phantom lines in Fig. 5, the counter balance weighs 42a, 42b are
positioned at the back (namely, left hand side of the drawing) of a
vertical line ~e) of axis 28a, 28b, and therefore urge the combined
structure or generator devices and sails to retract to the original
position of windless condition, and prevent an excessive shift of the
combined structure when the wind is weak, whereas the combined
structure without counterbalance weights is likely to be shifted exces-
sively, namely to an extent of about 30, even when the wind is rather
weak. Thus the sails are maintained in adjacent to the original posi-
tion when the wind is rather weak, and therefore stronger output can
: be effectively obtained in case of the weak wind. When the wind is
strong enough to urge the combined structure to shift more than about
30, the counterbalance weights are shifted to the forward position
of the vertical line cQ) of axis 28a, 28b as illustrated by phantom lines
of ~ig. 6. Thus, the combined structure of generator devices and
sails is pivoted rearwardly as illustrated by phantom lines. According-
ly an excessive increase of wind pressure onto the sails can be
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effectively and automatically prevented. Thus, the windmill structure
with counterbalance weights presents a constant electrical output no
matter what the velocity of the wind is.
As described above, in the windmill structure of the second
embodiment shown in Figs. 4, 5 and 6 position of the sails is adjusted
by changing the position of the weights, or by replacing the weights
by other heavier or lighter weights. Accordingly, an output to be
obtained can be adjusted. Further, the windmill is immediately posi-
tioned against the wind no matter what the wind direction is and even
when the wind direction is uncertain, by means of the pivotable vane 27.
According to the present invention, the combined structure of
electrical generator devices and sails is pivotably secured by the pivot
members without any complex mechanism of a sail rotation adjustment
device. Therefore, the windmill structure may be manufactured in a
simpler fashion, and substantially a constant output can be obtained
regardless of the wind velocity. In other words, sails area which
receives the wind is automatically adjusted, namely increased or
decreased, and always receives a constant pressure of the wind no
matter what the velocity of the wind is, resulting in a constant rotation
of the sails. Further, since the pivotal axis of the combined structure
of electrical generator devices and sails is positioned away from the
rotary shaft of the electrical generator devices, the rotary shaft is
not influenced by a reaction of gyromoment which is due to the rata-
tion of the sails, and there is no risk of any damage on to the rotary
shaft of the electrical generator devices.
Although the present invention has been described with
reference to the preferred embodiments thereof, many modifications
and alterations maybe made within the spirit of the present invention.
For instance, the sails and the T- shaped body may be modified into any
other configurations, and additional electrical generator devices and
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sails may be provided so as to obtain larger power. Further, it is
possible to provide a suitable device for relieving a rapid pivotal
movement of the combined structure of electrical generator devides
. and sails.
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