Abstract: A rotary wing system with a troublesome motion when rotating about a rotation axis, including a fluid tubular damper with a damper fluid for controlling the troublesome motion. The damper has an inboard and an outboard end, the inboard end attached to a rotary wing system inboard member proximate the rotation axis and the outboard end attached to a rotary wing system outboard member. The damper is terminated with a nonelastomeric end cap and contains damper fluid in at least an inboard and an outboard variable volume nonelastomeric working chamber which is worked by a nonelastomeric damper piston and a relative motion between the rotary wing system members. The damper includes a dynamically variable elastomeric volume compensator chamber in fluid communication with the working chambers, with the communication a controlled communication with the fluid flowed through control valves towards the working chambers.

Abstract: A fluid and elastomer device for isolating dynamic loading between members connected to the device, the fluid and elastomer device comprising: an inner member that defines a compliance chamber; an outer member that defines an outer housing chamber; an elastomeric element flexibly interconnecting said inner member relative to said outer member; a passageway located in the compliance chamber and flow connecting the compliance chamber with a primary working chamber; a secondary compliance member joined to the passageway in the compliance chamber; a volume compensator located in the housing chamber the volume compensator comprising spring means, piston member at one spring end and a diaphragm member that overlies the piston; a member located between the compliance and housing chambers, the member being moveable with the outer housing, the moveable member in combination with the diaphragm defining a compensator chamber; and a volume of working fluid in said chambers and passageway.

Abstract: A fluid isolator apparatus (20) for isolating vibration between a vibrating member, such as a helicopter transmission or pylon and another structure, such as a helicopter fuselage. In one aspect, the fluid and elastomer apparatus (20) includes an inner member (24), an outer member (22), and an elastomer element (26) flexibly interconnecting them. First (30) and second (34) operating chambers are interconnected by a passageway (36). Fluid (37) oscillates between the operating chambers (32, 34) through passageway (36). A spring (42) flexibly suspends the piston (40) such that dynamic motion between said inner and outer member (24, 22) displaces piston (40) and spring (42). Preferably the a hollow cavity (28) houses both the piston (40) and a metal coil spring (42). The stiffness of the coil spring (42) may be interchanged to adjust a resonant parameter. Optionally, the piston mass itself or an additional tuning mass (58) mounted on the piston (40) may be used to accomplish tuning.

Abstract: A fluid isolator apparatus (20) for isolating vibration between a vibrating member, such as a helicopter transmission or pylon and another structure, such as a helicopter fuselage. In one aspect, the fluid and elastomer apparatus (20) includes an inner member (24), an outer member (22), and an elastomer element (26) flexibly interconnecting them. First (30) and second (34) operating chambers are interconnected by a passageway (36). Fluid (37) oscillates between the operating chambers (32, 34) through passageway (36). A spring (42) flexibly suspends the piston (40) such that dynamic motion between said inner and outer member (24, 22) displaces piston (40) and spring (42). Preferably the a hollow cavity (28) houses both the piston (40) and a metal coil spring (42). The stiffness of the coil spring (42) may be interchanged to adjust a resonant parameter. Optionally, the piston mass itself or an additional tuning mass (58) mounted on the piston (40) may be used to accomplish tuning.

Abstract: A fluid damper to damp unwanted vibration between a first member (21) and a second member (23, 23'), such as between a rotor blade and hub within a helicopter rotor system. According to a first aspect, the fluid damper (20) includes an outer member (22), first and second inner members (24, 24'), first and second elastomeric elements (26, 26'), a hollow (28), a divider (30) subdividing hollow (28) into first (32) and second (32') operating chambers, a connector (34) interconnecting first (24) and second (24') inner members, a fluid passageway (36) interconnecting operating chambers (32, 32'), a fluid (38) contained within said passageway (36) and operating chambers (32, 32'), and a volume compensator (40) including a compensator chamber (42) housed within one of first (24) and second (24') inner members. In another aspect, an annular bubble trap (58) is formed in a wall portion (62) of the operating chamber (32) to focus any air bubbles into a fill port (54) during fill.

Abstract: A method and apparatus is described for limiting transient motions between an aircraft power member and aircraft structure. The apparatus incorporates a coupler (20) for use with inertial-type mounts and includes a body portion (21) having a coupler piston (32) telescopically received therein. Upon exceeding a transient relative motion which causes a fluid flow velocity to be exceeded, seat (38) formed on coupler piston (32) interacts with lip (39) on body portion (21) to cause a fluid flow restriction. This method and apparatus restricts and limits transient motions, i.e., acts as a snuffer, to limit further relative motion between an aircraft power member (54) and an aircraft structural member (52). The coupler piston (32) preferably includes a flexible seal (38) formed thereon and orifice (40) therethrough for providing additional throttle-type damping upon snubbing.

Abstract: A method is described for identifying the primary load path of a particular engine. An elastomeric mount may then be made laterally soft in a first (in the disclosed case, the tangential) direction and more rigid in the direction of the primary load path. Efforts can then be directed to dynamically softening the mount in the primary load path. Specific apparatus may include passive fluid devices, active fluid devices, passive non-fluid devices and active non-fluid devices. In the case of a fluid mount, another feature of the invention is to have an auxiliary fill port of the volume compensator in alignment with at least one and, preferably both, of the primary fill port for the mount and the inertia track to facilitate filling.

Abstract: The invention relates to a fluid device for providing high load carrying capacity in an one direction and which provides a high level of damping along a substantially perpendicular direction. This is achieved by a device which includes an inner member and an outer member and a flexible section causing a connection therebetween, said flexible section exhibiting a substantially higher stiffness along one axis, a fluid cavity formed within said device, a piston attached to one of said inner member and said outer member, said piston being substantially surrounded by, and submersed in said fluid. In one embodiment, the piston includes a piston area A.sub.p which is substantially greater than 1/2 the fluid cavity area A.sub.c. Movement of the piston within the fluid cavity causes a damping force comprising a throttling component as well as a viscous shear component. Means are disclosed for substantially increasing the viscous shear component and throttling component including novel piston concepts.

Abstract: A hybrid fluid and elastomer damper. A damper, which may be utilized as a lead-lag damper for a helicopter rotor application, reduces vibratory motion transmitted axially, torsionally and angularly between a pair of components such as a rotor and a blade by hysteresis of the elastomer and throttling and shearing of the fluid through a narrow annular passageway. The hybrid damper captures the best features of both the elastomer and fluid dampers while avoiding many of the disadvantages of each.

Abstract: A damping device which provides superior damping stiffness K", has linear damping characteristics as a function of amplitude and for which the temperature sensitivities of stiffnesses K*, K", K' have been minimized. The device includes a first second fluid-filled chambers which are interconnected by a passageway. The length and diameter of the passageway, as well as the fluid viscosity, are chosen to give the optimum damping characteristics. Further, a plurality of spring loaded pressure relief valves are integrated into the assembly to allow more flow area to open when a threshold pressure is encountered, thereby reducing the internal pressures and dynamic stiffness K* at cold temperatures.

Abstract: A torque-restraint mounting system for connecting an aircraft engine to a structure including at least two hydraulic mountings and at least one other resilient mounting. At least two of the hydraulic mountings are fluidicly interconnected via a fluid filled conduit. This allows for the torque to be reacted between the aircraft engine and the structure by placing the fluid in compression. The relative torque-induced displacement occurring between the aircraft engine and the structure for any specific operating copndition is counteracted by tuning the amount or volume of fluid within the torque-restraint system, or by tuning the coefficient of thermal expansion of the fluid. Thus, as the torque-restraint mounting system heats up, the aircraft engine will change rotational position such that its room temperature untorqued orientation can be maintained. This can have significant benefits in terms of increasing service life of the engine mounting system.

Abstract: A reversible endless belt rotary coupling particularly suited for use in connecting a drive shaft and driven shaft permitting the driven shaft to rotate in either, rotational direction and to rotate about an axis that may be angularly misaligned with respect to the rotational axis of the drive shaft. The coupling includes a series of preloaded endless belts embedded in an elastomer matrix material, arranged tangentially with respect to the connected shafts and connected thereto by bobbin-like spools at the ends of the belts. The endless belts are axially stiff to accommodate tensile and compression loads and are flexibly and torsionally soft to accommodate the motion while transferring torque between the drive and driven shaft.

Abstract: A lightweight, flexible coupling suitable for transmitting torque and accommodating axial and angular misalignment between drive and driven members. The coupling includes at least one reinforcing rim disposed between a pair of hubs having a plurality of projecting pins about which are secured filaments that are coated with a flexible matrix material. The filaments are geodesically wrapped from the hub one side of the reinforcing ring and then to the hub on the opposite side of the reinforcing ring. The driven and driven members are respectively attached to the projecting pins.

Abstract: A mount capable of being pressed into an installed position in a hole in a plate. The mount has inner and outer concentric annular elements connected together by an intermediate flexible thermoplastic elastomeric web. The outer annular element has a peripheral groove which receives the plate and a deflectable wall with a chamfered outer surface and a series of slots. The flexible web permits the inner element to vibrate with respect to the plate and thereby isolate an item from the plate.

Abstract: The damper assembly has improved valve means that includes at least one annular movable valve member of the voice-coil type. Such valve member is formed at least in part of composite material that increases the strength and stiffness of the member, while reducing its coefficient of thermal expansion and its weight. In a preferred embodiment of the invention, the assembly includes two movable annular valve members which are driven in unison with each other such that when one occupies a flow-permitting position the other occupies a flow-inhibiting position. Check valves utilized in the assembly preferably are of a resilient split-ring type.

Abstract: A rotary energy storage device comprises a rotor and a hub for mounting the rotor on a shaft. The rotor is joined to the hub by an interlayer disposed between the rotor and hub. One surface of the interlayer is bonded to a mounting surface of the hub. A second surface of the interlayer, which is opposite the first surface, is bonded to a surface of the rotor which is opposite and spaced from the mounting surface of the hub. Due to differences in their constructions, such as their relative dimensions, the rotor and the hub experience different strains due to the centrifugal forces exerted during rotation of the energy storage device. The difference between the strain at the mounting surface of the hub and the strain at the opposed surface of the rotor induces a shear stress in the interlayer. To accommodate the induced shear stress, the interlayer has a thickness and a shear modulus which permit the interlayer to deflect in response to the difference in strains without structural or bond failure.

Abstract: A rotor blade retention system connects an elongated rotor blade to a rotor hub that is rotatable about its central axis. The connected rotor blade normally extends generally radially from the hub and is rotatable with the hub. The retention system includes a pair of bearings that are interconnected in parallel load transmitting relationship. Both bearings are connected in serial load transmitting relationship with a flap hinge. One bearing is relatively stiff along the longitudinal axis of the rotor blade and is less stiff in directions transverse to the longitudinal blade axis. The other bearing is most stiff in directions transverse to the rotor blade axis and is less stiff along the axis. Both bearings define effective elastic centers which are located along the longitudinal blade axis, but the two elastic centers are spaced from each other. The two bearings accommodate lead-lag motions of the rotor blade.

Abstract: A propeller assembly comprises a rotatable drive shaft and two separate blade subassemblies resiliently coupled to and driven by the shaft. Each blade subassembly has a pair of interconnected propeller blades extending in opposite directions radially of the shaft. The blade subassemblies are disposed in parallel planes with the blades of one subassembly oriented transversely of the blades of the other subassembly. Rotational movement of the shaft is transmitted to the blade subassemblies through viscoelastic material which is torsionally loaded and stressed in shear. The viscoelastic material resiliently permits and damps in plane or lead-lag movement of each blade subassembly relative to the drive shaft. The subassemblies are also interconnected so that the viscoelastic material resiliently permits and damps relative in-plane movement between the subassemblies.