Abstract: A replacement for cylindrical dowel nuts is provided and is a hollow cylindrical nut with a threaded hole on top and an unthreaded hole at the bottom which is for the threaded shank to enter. This hollow dowel nut elastically compresses during tightening to act like a lock-washer to prevent loosening. Several solutions are provided to make the top of the nut thicker to fit more thread coils than what wall thickness would otherwise permit. To improve loosening prevention further and also provide overtightening prevention a hollow nut with flatter bottom and a narrow gap bisecting the lower hole are used which during tightening cause right and left edges of said gap to be pushed towards the bolt strongly gripping it which prevents overtightening and loosening. “C” shaped nuts also provided which cause misalignment and jamming in the thread when compressed thereby also preventing loosening and overtightening.

Abstract: A blade for cycloidal rotor or propeller is provided with means to dynamically change within each revolution: its relative pivot point location along chord, extend or retract trailing edge, make actuated or passive turns of trailing edge flap, dynamically control stiffness of at least the flexible trailing edge, open or close strips covering much of blade surface area to allow flow through the blade. These features will enable the control system to continually adjust each blade to its immediate operating environment along the orbit.

Abstract: A cycloidal rotor is provided having a flexible by actuators or self-flexing blade-positioning tack, which can be brought into shape corresponding to currently desired blade orbit. This rotor can also be provided with frontal shielding or partial enclosure to assure that rotor operates at any speed as if in hovering flight; rotor track can be inclined to produce forward thrust or external thrusters can be used. Optionally in other embodiments blade orbit shape is determined by a variable cam mechanism or the inclination of blade positioning track of fixed shape to produce a change of its projected shape onto blades' plane of operation thus changing blades elliptic orbit. Blade centrifugal force countervailing mechanism is also proposed.

Abstract: In a number of embodiment the washers of this invention have been provided with the narrowing central hole wherein the washer is being compressed during tightening thereby gripping the bolt and preventing its further turning whereas the nut and the washer are immobilized relative to each other. In another embodiments when the washer is compressed, wedges and preventing its further turning and thus preventing any increase in tightening level.

Abstract: In one embodiment of this invention the washers have been provided with the bottom teeth, which sink into the wood surface during nut tightening thus immobilizing the washer, and a turnable upward flap which when bent upward and pressing against the nut facet is preventing its loosening. In another similar embodiment the washer is provided with turnable upward bracket which has a tip entering the screw top's socket or slit, thereby immobilizing the screw and preventing its loosening. As a replacement for cylindrical nuts, a number of types of elongated nuts with open “C”-like cross-sections which elastically compress with their threaded hole becoming misaligned with the screw thereby jamming it. Said misalignment prevents overtightening and contributes to prevention of loosening, while the elastic compression of this nut acts in a way similar to a spring lock-washer preventing loosening.

Abstract: A blade is provided for the cycloidal marine propellers or cycloidal aerial rotors. Said blade is provided with the capabilities, in response to the control system commands to dynamically and in real time; vary its relative pivot point position, change its planform by extending or retracting a trailing edge extension, differentially if needed on the right and left, turn the flap along the trailing edge in either direction or allow it to be turned by the flows. Said blade is also optionally provided with one or more elastic trailing edges whose stiffness is dynamically, and possibly differentially along the blade span, variable by the control system. For the reversal of the leading and trailing edges for operation in reverse airflow and other conditions the blades are provided with edges that can be made rigid when functioning as the leading edge and flexible if needed when functioning as the trailing edge.

Abstract: A blade for the cycloidal marine propellers or cycloidal aerial rotors operative, in response to control system commands, to dynamically; flex along its chord, vary its relative pivot point position, change its planform by extending or retracting a trailing edge extension, differentially, turn the flap along the trailing edge in either direction or allow it to be turned by the flows. For the reversal of the leading and trailing edges for operation in reverse airflow and other conditions the blades are provided with edges that can be made rigid when functioning as the leading edge and flexible if needed when functioning as the trailing edge. Also, the blades are configured to vary and reshape their cross-sectional profile thickness. Finally, the blades are given on command flow permeability along much of their surface.

Abstract: To eliminate stability issues in forward flight due to oncoming flow interfering with the flows produced inside the rotor, rotor shielding or enclosure are used giving it the ability to operate steadily at various forward speeds. Furthermore to improve performance and flows cycloidal rotor/propeller has blades travelling along generally non-circular and elongated track and is able to transition to a variety of other track shapes having corresponding blade orbit shapes. Track shape variation designs similar to such track designs for blade trajectory determination are used for the purpose of changing the blades pitch and their cross-sectional shape. One embodiment uses fixed elliptic shape track upon which run carriages connected to blade shafts. Said track can be inclined about its major axis thereby changing its shape projection onto the plane in which blades travel thus changing the elliptic shape of their orbit.

Abstract: Springs of different types are provided with the ability to dynamically change stiffness. A number of embodiments feature hollow tubing wherein stiffness change is accomplished due to the pressure change inside the tubing which affects the stresses in tubing walls. In other embodiments inside pressure change causes variability in tubing's cross-section shape and size leading to large changes in stiffness. A number of embodiments feature spring coil diameter variability achieved by a variety of means and resulting in highly substantial changes in stiffness and for some embodiments spring length variability thus providing them with actuation capability in addition to stiffness variability.

Abstract: A lock-washer of conical, annular or other shapes capable of elastic flattening when the threaded connection, of which it is a part, is tightened and having tabs along the perimeter of the central hole. For most embodiments the tabs' tips form a circle of a diameter slightly larger than that of a threaded part which is to pass through the central hole. When during tightening the axial force acting on the lock-washer reaches a pre-determined level and the lock-washer flattens, its central hole diameter decreases and the tab tips enter the thread channel, which will cause the thread to jam, thus preventing further tightening, thereby limiting the axial load in the threaded connection to a pre-determined level. Another embodiment provides a lock-washer which compresses and expands radially during tightening providing a visual and/or audible signal for the worker when said expansion and a corresponding axial load reach the designated level.

Abstract: The bolts of this invention have been provided with the various means for preventing torque transmission to the bolt head when the nut is being tightened, thereby eliminating the need to hold it by a wrench while the nut is being tightened. A nut with a helical or similar cut is provided in order to assure more even distribution of stress among its thread coils. A few different flexible bolts are provided for assembling misaligned flanges and other misaligned connections. Lastly fasteners comprising very strong and light synthetic fiber string with a simple hoist-like assembly on one end and a round stopper-head on the other have been provided, not using the thread at all, to replace the heaviest, longest and most expensive bolts and nuts used on large pipes and pressure vessels or in applications where weight reduction is important.

Abstract: A system and a method for tracking items stored in a refrigerator which includes the identifying unit comprising a few known devices such as bar code reader or voice command processor for identifying the incoming and outgoing items also including an olfactory sensor. Said sensor in addition to identification is to be used also for assessing the items' degree of freshness for the purpose of determination of its actual expected maximum storage time—this determination will be made by the computer processor accessing the pertinent database(s) while using the digital smell signature for said access, when necessary. Said database will contain the storage data for opened or unpacked or cooked items for which the storage time data on the package is not applicable as well as possibly the items ingredients and the nutritional content.

Abstract: A blade is provided for the cycloidal marine propellers or cycloidal aerial rotors. Said blade is provided with the capabilities, in response to the control system commands to dynamically and in real time; flex itself along its chord in any required way, vary its relative pivot point position, change its planform by extending or retracting a trailing edge extension, differentially if needed on the right and left, turn the flap along the trailing edge in either direction or allow it to be turned by the flows. Said blade is also optionally provided with one or more elastic trailing edges whose stiffness is dynamically, and possibly differentially along the blade span, variable by the control system. For the reversal of the leading and trailing edges for operation in reverse airflow and other conditions the blades are provided with edges that can be made rigid when functioning as the leading edge and flexible if needed when functioning as the trailing edge.

Abstract: Springs of different types are provided with the ability to dynamically change stiffness. For one embodiment turning the elastic beams with elongated cross-section inside a leaf spring's housing plate, leaf springs stiffness is varied. Friction forces between plates are also controlled by using a thin layer of electro-rheological fluid between plates whose viscosity is greatly varied by application of voltage. Second embodiment springs made of hollow tubing filled with oil wherein inside pressure is changed by an actuated membrane or piston whose movement drastically increases the hydrostatic pressure inside the tubing and thus increases tensile stress in the tubing's wall and expands the diameter of tubing which may be of cross-section purposely suited for expansion, thereby increasing its stiffness or decreasing it with any desired frequency or changing the stiffness possibly in milliseconds for a period of time.

Abstract: A cycloidal rotor system having airfoil blades travelling along a generally non-circular, elongated and, in most embodiments, dynamically variable orbit. Such non-circular orbit provides a greater period in each revolution and an optimized relative wind along the trajectory for each blade to efficiently maximize lift when orbits are elongated horizontally, or thrust/propulsion when orbits are vertically elongated. Most embodiments, in addition to having the computer system controlled actuators to dynamically vary the blade trajectory and the angle of attack, can also have the computer system controlled actuators for dynamically varying the spatial orientation of the blades; enabling their slanting motion upward/downward and/or backsweep/forwardsweep positioning to produce and precisely control a variety of aerodynamic effects suited for providing optimum performance for various operating regimes, counter wind gusts and enable the craft to move sideways.

Abstract: A cycloidal rotor system having airfoil blades travelling along a generally non-circular, elongated and, in most embodiments, dynamically variable orbit. Such non-circular orbit provides a greater period in each revolution and an optimized relative wind along the trajectory for each blade to efficiently maximise lift when orbits are elongated horizontally, or thrust/propulsion when orbits are vertically elongated. Most embodiments, in addition to having the computer system controlled actuators to dynamically vary the blade trajectory and the angle of attack, can also have the computer system controlled actuators for dynamically varying the spatial orientation of the blades; enabling their slanting motion upward/downward and/or backsweep/forwardsweep positioning to produce and precisely control a variety of aerodynamic effects suited for providing optimum performance for various operating regimes, counter wind gusts and enable the craft to move sideways.