Rotary kinetic fluid motors or pumps – With means for controlling casing or flow guiding means in... – Natural fluid current force responsive
Reexamination Certificate
2002-09-25
2004-06-15
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
With means for controlling casing or flow guiding means in...
Natural fluid current force responsive
C415S044000, C415S140000, C415S907000
Reexamination Certificate
active
06749394
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates generally to displays for decorative, advertising, and other promotional purposes, and more particularly to a rotating display apparatus powered by the wind for rotation about a vertical axis.
2. Description of Related Art
A rotating display apparatus (RDA) displays decorative objects, advertising, or other information as it rotates. An RDA that rotates about a vertical axis falls under the general description of a vertical axis wind turbine (VAWT), and a VAWT fits into one of two categories: either it has a fixed or rigid rotor structure, or it has movable members, reactive elements, airfoils, vanes, or the like. Many VAWTs in the first category, those with a fixed or rigid rotor structure, are derivations of the roof ventilator. Others of that category are adaptations of the basic “S” shape with typically two or three, but potentially up to six, sides or facets.
VAWTs in the second category, those with movable members and so forth, are either proactive or reactive. The airfoils or elements of a proactive VAWT are positioned in relationship to the wind via gears, cams, cables, pulleys, rods, or any number of other means in order to produce lift and turn the rotor. To accomplish this, the system must be aware of the wind direction, which is usually accomplished by means of a weathervane-type mechanism. One characteristic of this design type is the typically symmetrical angle of attack profile of the elements, usually configured for crosswind lift on the windward and leeward portions of the cycle, and faired on both the downwind and upwind legs. Pros and cons of this approach are described in U.S. patent application Ser. No. 10/178,209.
In a reactive VAWT, the airfoils or elements position themselves in response to fluid pressures experienced locally. These forces are produced by a combination of the true wind and the relative wind created by rotation. Some existing RDAs are this type. U.S. Pat. No. 482,178, for example, describes an advertising device that uses weights on a curved horizontal member, like a tightrope walker uses a balance bar. At each end of the horizontal member is a “package” (e.g., a medicine bottle) and support for a vane, hinged on its edge by a thin vertical support, which allows the down-wind vane to swing outward and catch the airflow, and the upwind vane to swing back to reduce friction. The patent illustrates the large supporting base of the unit echoing the “package.” This is a simple mechanism, but it is probably as effective as some more complicated versions. This device appears to be intended to support specific products as the “packages” and base structure would be uniquely shaped in manufacturing. No accommodation for a generic version capable of supporting a range of “packages” is suggested.
U.S. Pat. No. 704,002 describes a wind actuated advertising device that is a bit more complicated, but basically a version of the advertising device discussed above. The vanes are hinged near the one-third point, but no mention is made of balancing them around the pivot point. A single-function spring dampener is attached to each radial arm, allowing the vanes to rotate freely until contacting the dampener finger along the radial position of the hub arm, on either side of the element. Functionality of the vanes is such that the downwind vanes will swing out to catch the airflow and the upwind vanes will fare into the wind. The spring mechanism would be called upon to dampen the potentially violent transitional movements of the vanes.
U.S. Pat. No. 1,232,895 describes a revolving sign. The airfoil-shaped elements are not damped or constrained in any manner, and movement is produced in a rather random and haphazard way by independent movement of the elements in reaction to changes in wind direction and speed. Being unconstrained, all the elements will align simultaneously with the wind. The description suggests that the device be put near a window with an electric fan blowing on it—perhaps in order for the interference between the fan and the outside wind to cause the device to move. The intent is obviously for the display of advertising as opposed to a continuously rotating mechanism.
U.S. Pat. No. 1,511,965 describes an advertising device that uses simple flat elements that swing broadside to the wind in the downwind phase and swing outward to streamline into the wind on the upwind leg. Several armature configurations a represented. The most obvious feature of this design is its unbalanced nature. A great deal of strain will be encountered in the main pivot point and support structure, and the elements that swing outward will momentarily flail wildly in the wind. Centrifugal force will also take a toll in swinging the panels into the wind—acting as an effective brake. This type of system would tend to run very sporadically, in fits and starts.
U.S. Pat. Nos. 1,534,634 and 1,534,635 describe a wind sign that is similar to the revolving sign described in U.S. Pat. No. 1,232,895 in that the elements rotate freely and independently. Based upon the description (i.e., “. . . it has been found by actual use of the device that all of the vanes will point in substantially the same direction when subjected to the wind, and the pressure of the wind upon the vanes causes the rotatable frame to rotate slowly . . . ”), if all the vanes point simultaneously into the wind, there is no imbalance of forces to produce rotation. The patent presents information on the panels, without considering the aerodynamic principles that would permit the unit to revolve consistently.
U.S. Pat. No. 2,030,769 describes an advertising device that uses drag downwind and fairing upwind and is closely similar to the advertising device described in U.S. Pat. No. 1,511,965 discussed above. Because of the way the figures are illustrated, and the fact that the units are shown rotating in opposite directions, this is not immediately obvious. It will be subject to the same balance issues and performance shortcomings of the earlier design.
U.S. Pat. No. 2,076,784 describes a display device, of the “roof ventilator” type, that is mentioned here because it shows the presentation of a three-dimensional object. U.S. Pat. No. 3,292,319 describes a sea gull guard, with a different intended use, but one version shown gives an example of reactive elements being used to produce crosswind lift exclusively.
FIG. 4
in that patent shows a rotating apparatus with reactive elements (vanes) constrained between a ninety degree free movement range, with the downwind drag phase (startup power) being inefficient due to the forty-five offset of the vane. However, since the unit is intended to be used in areas of steady wind (e.g., marinas) and given its long moment arm, lightweight mass, and low wind resistance mounting radial, self-starting issues should not be a concern.
The foregoing illustrates that none of the prior art device reviewed above explore the concept of accommodating shaped, two-dimensional or three-dimensional reactive elements and the use of standardized mounting features for easy interchangeability. In addition, none address mechanisms for avoiding storm damage and most appear vulnerable to high winds. Furthermore, none of the devices address means of adjusting element position or optimizing efficiency. Although not a top priority, higher efficiency translates into better performance at lower wind speeds. Moreover, none of the devices use the five-phase movement described in U.S. patent application Ser. No. 10/178,209.
The two most common approaches in the prior art reviewed above are (a) drag 180 degrees, fair 180 degrees, and (b) crosswind lift only. For the first approach, the elements in the above designs rotate 180 degrees on their axes, create drag thrust on the downwind phase, and use some strategy to reduce the drag on the upwind leg. Units using this approach tend to turn more slowly, but start more easily, than lift-only designs. For the second approach, the reactive elements in the above designs typically rotate 90 degre
Hanson Loyal McKinley
Look Edward K.
White Dwayne J.
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