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Results for “PIVOT”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 181 records · Page 10

All sources NASA NTRS DOE OSTI

NASA NTRS1993

Supersonic aeroelastic instability results for a NASP-like wing model

Two wing-alone wind-tunnel models were tested in the NASA Langley Unitary Plan Wind Tunnel facility to study the static divergence behavior of such configurations and to provide a data base for correlation with supersonic analytical predictions. One model had a four percent maximum thickness airfoil and the other had an eight-percent maximum thickness airfoil. The wing models had low aspect ratios and highly swept leading edges. Results show that decreasing airfoil thickness, moving the wing-pivot location upstream, or increasing the pitch-pivot stiffness have the beneficial effect of increasing the divergence dynamic pressures. The calculations accurately predicted the trend of experimental divergence dynamic pressure with Mach number.

Cole, Stanley R.↗

NASA NTRS1942

The Porpoising Characteristics of a Planing Surface Representing the Forebody of a Flying-Boat Hull

Porpoising characteristics were observed on V-body fitted with tail surfaces for different combinations of load, speed, moment of inertia, location of pivot, elevator setting, and tail area. A critical trim was found which was unaltered by elevator setting or tail area. Critical trim was lowered by moving pivot either forward or down or increasing radius or gyration. Increase in mass and moment of inertia increased amplitude of oscillations. Complete results are tabulated and shown graphically.

HULL BOTTOMS, VEE↗

NASA NTRS1993

Bladder operated robotic joint

This invention is a robotic joint which is operated by inflatable bladders and which can be used in applications where it is desired to move or hold an object. A support block supports an elongated plate to which is pivotally attached a finger. A tension strip passes over a lever attached to the finger and is attached at its ends to the support block on opposite sides of the plate. Bladders positioned between the plate and the tension strip on opposite sides of the plate can be inflated by pumps to pivot the finger, with one of the bladders being inflated while the other is being deflated.

Robertson, Glen A.↗

NASA NTRS1994

High precision moving magnet chopper for variable operation conditions

In the context of an ESTEC technology contract, a Chopping Mechanism was developed and built with the Far Infrared and Submillimeter Telescope (FIRST) astronomy mission as a reference. The task of the mechanism is to tilt the subreflector of the telescope with an assumed mass of 2.5 kg about one chopping axis at nominal frequencies of up to 5 Hz and chopping angles of up to +/- 11.25 mrad with high efficiency (minimum time for position change). The chopping axis is required to run through the subreflector vertex. After performing a concept trade-off also considering the low operational temperatures in the 130 K range, a design using moving magnet actuators was found to be the favorite one. In addition, a bearing concept using flexible pivots was chosen to meet the high chopping accuracy required. With this approach, a very reliable design could be realized, since the actuators work without any mechanical contact between its moving and fixed parts, and the only bearings used are two flexible pivots supporting the subreflector mounting interface. The mechanism was completely built in titanium in a lightweight and stiff design. The moving magnet actuators were designed to meet the stringent requirements for minimum risetime (time necessary to move from one angular position to a new one) in the 20 msec range. The angular position and the corresponding chopping frequency as well can be arbitrarily selected by the user.

Aicher, Winfried↗

NASA NTRS1995

Automatic locking knee brace joint

This invention is an apparatus for controlling the pivotal movement of a knee brace comprising a tang-and-clevis joint that has been uniquely modified. Both the tang and the clevis have a set of teeth that, when engaged, can lock the tang and the clevis together. In addition, the tang is biased away from the clevis. Consequently, when there is no axial force (i.e., body weight) on the tang, the tang is free to pivot within the clevis. However, when an axial force is exerted on the tang, the tang is pushed into the clevis, both sets of teeth engage, and the tang and the clevis lock together.

Weddendorf, Bruce↗

NASA NTRS1995

Apparatus and method for cold welding thin wafers to hard substrates

An apparatus for coating and bonding parts in a vacuum that includes a floating mount assembly holding one part and applying a bonding load to the parts is discussed. A pivoting mount assembly holds one part and is pivoted between a coating position and a bonding position. At least one coating source is provided for depositing a thin film of a metal onto a surface of each of the parts to improve the cold weld between the two parts. A restraining lever controls the application of the bonding load to the parts. The coating and bonding process occurs in a vacuum chamber with a single set-up.

Oeftering, Richard↗

NASA NTRS1996

Large capacity oblique all-wing transport aircraft

Dr. R. T. Jones first developed the theory for oblique wing aircraft in 1952, and in subsequent years numerous analytical and experimental projects conducted at NASA Ames and elsewhere have established that the Jones' oblique wing theory is correct. Until the late 1980's all proposed oblique wing configurations were wing/body aircraft with the wing mounted on a pivot. With the emerging requirement for commercial transports with very large payloads, 450-800 passengers, Jones proposed a supersonic oblique flying wing in 1988. For such an aircraft all payload, fuel, and systems are carried within the wing, and the wing is designed with a variable sweep to maintain a fixed subsonic normal Mach number. Engines and vertical tails are mounted on pivots supported from the primary structure of the wing. The oblique flying wing transport has come to be known as the Oblique All-Wing (OAW) transport. This presentation gives the highlights of the OAW project that was to study the total concept of the OAW as a commercial transport.

Galloway, Thomas L.↗

NASA NTRS1996

Apparatus and Method for Cold Welding Thin Wafers to Hard Substrates

An apparatus for coating and bonding parts in a vacuum includes a floating mount assembly holding one part and applying a bonding load to the parts. A pivoting mount assembly holds one part and is pivoted between a coating position and a bonding position. At least one coating source is provided for depositing a thin film of a metal onto a surface of each of the parts to improve the cold weld between the two parts. A restraining lever controls the application of the bonding load to the parts. The coating and bonding process occurs in a vacuum chamber with a single set-up.

Oeftering, Richard C.↗

NASA NTRS2001

Compact Dexterous Robotic Hand

A compact robotic hand includes a palm housing, a wrist section, and a forearm section. The palm housing supports a plurality of fingers and one or more movable palm members that cooperate with the fingers to grasp and/or release an object. Each flexible finger comprises a plurality of hingedly connected segments, including a proximal segment pivotally connected to the palm housing. The proximal finger segment includes at least one groove defining first and second cam surfaces for engagement with a cable. A plurality of lead screw assemblies each carried by the palm housing are supplied with power from a flexible shaft rotated by an actuator and output linear motion to a cable move a finger. The cable is secured within a respective groove and enables each finger to move between an opened and closed position. A decoupling assembly pivotally connected to a proximal finger segment enables a cable connected thereto to control movement of an intermediate and distal finger segment independent of movement of the proximal finger segment. The dexterous robotic hand closely resembles the function of a human hand yet is light weight and capable of grasping both heavy and light objects with a high degree of precision.

Lovchik, Christopher Scott↗

NASA NTRS1961

Low-Speed Investigation of the Effects of Large Wing-Sideslip Angles on the Aerodynamic Characteristics of Two Arrow-Wing-Fuselage Arrangements

A wind-tunnel investigation has been made of two methods proposed to reduce the high sinking speeds and improve the landing characteristics of low-aspect-ratio hypersonic airplanes by placing the wing at large angles of sideslip to increase its effective aspect ratio. The models investigated had conical fuselages and arrow wings, with a leading-edge sweep-back of 77.4deg, an aspect ratio of 1.23, and a 4-percent-thick straight-wedge section. For one model, the wing was pivoted on the fuselage to angles of wing sideslip from 0 to 90deg. For the other model, the wing was fixed to the fuselage, and the wing and fuselage were yawed together to sideslip angles from 0 to 90deg. The investigation was made in the Langley 300-MPH 7- by 10-foot tunnel for an angle-of-attack range from -8 to above 28deg. Longitudinal stability and control through the use of horizontal tails with elevators was studied on the pivoted-wing configuration. The roll control for both configurations was studied with deflection of the apex portion of the wing about an axis along the wing center line. The use of flaps with the wing at large sideslip angles was also investigated.

Thomas G Gainer↗

NASA NTRS2006

Thrust Stand for Electric Propulsion Performance Evaluation

An electric propulsion thrust stand capable of supporting testing of thrusters having a total mass of up to 125 kg and producing thrust levels between 100 microN to 1 N has been developed and tested. The design features a conventional hanging pendulum arm attached to a balance mechanism that converts horizontal deflections produced by the operating thruster into amplified vertical motion of a secondary arm. The level of amplification is changed through adjustment of the location of one of the pivot points linking the system. Response of the system depends on the relative magnitudes of the restoring moments applied by the displaced thruster mass and the twisting torsional pivots connecting the members of the balance mechanism. Displacement is measured using a non-contact, optical linear gap displacement transducer and balance oscillatory motion is attenuated using a passive, eddy-current damper. The thrust stand employs an automated leveling and thermal control system. Pools of liquid gallium are used to deliver power to the thruster without using solid wire connections, which can exert undesirable time-varying forces on the balance. These systems serve to eliminate sources of zero-drift that can occur as the stand thermally or mechanically shifts during the course of an experiment. An in-situ calibration rig allows for steady-state calibration before, during and after thruster operation. Thrust measurements were carried out on a cylindrical Hall thruster that produces mN-level thrust. The measurements were very repeatable, producing results that compare favorably with previously published performance data, but with considerably smaller uncertainty.

Polzin, Kurt A.↗

NASA NTRS1988

Orbital maneuvering vehicle end effectors

An end effector device (A) for grasping and holding an article such as a handle (18) of a space telescope is disclosed. The device includes a V-shaped capture window (74) defined as inclined surfaces (76, 78) in parallel face plates (22, 24) which converge toward a retainer recess (54) in which the handle is retained. A pivotal finger (30) meshes with a pair of pivoted fingers (26, 28) which rotate in counterrotation. The fingers rotate to pull a handle within the capture window into recess (54) where latches (50) lock handle (18) in the recess. To align the capture window, plates (22, 24) may be cocked plus or minus five degrees on base (64).

Myers, W. Neill↗

NASA NTRS1991

Blade tip clearance control apparatus using bellcrank mechanism

A clearance control apparatus has a positioning mechanism for controlling clearance between rotor blade tips and a shroud segment of a gas turbine engine casing. The positioning mechanism is supported by the casing, coupled to the shroud segment, and actuatable for moving the shroud segment toward and away from the rotor blade tips to reach a position at which a desired clearance is established. The mechanism includes a shaft and a bellcrank actuating assembly. The shaft is mounted through a passage defined by a mounting structure on the casing for radial movement along a longitudinal axis of the shaft toward and away from the rotor axis and is coupled at its inner end to the shroud segment. The bellcrank actuating assembly is coupled to an outer end of the shaft and mounted to the casing adjacent the shaft for pivotal movement about an axis spaced from and extending transverse to the longitudinal axis of the shaft. The pivotal movement of the bellcrank actuating assembly produces radial movement of the shaft and shroud segment therewith toward and away from the rotor blade tips.

Corsmeier, Robert J.↗

NASA NTRS1993

Multi-access laser communications transceiver system

A satellite system for optical communications such as a multi-access laser transceiver system. Up to six low Earth orbiting satellites send satellite data to a geosynchronous satellite. The data is relayed to a ground station at the Earth's surface. The earth pointing geosynchronous satellite terminal has no gimbal but has a separate tracking mechanism for tracking each low Earth orbiting satellite. The tracking mechanism has a ring assembly rotatable about an axis coaxial with the axis of the field of view of the geosynchronous satellite and a pivotable arm mounted for pivotal movement on the ring assembly. An optical pickup mechanism at the end of each arm is positioned for optical communication with one of the orbiting satellites by rotation of the ring.

Ross, Monte↗

NASA NTRS1997

Deployment hinge

A hinge (20) includes two hinge plates (22, 24) and a connecting hinge pin (32). A coil spring (48) supported on a bushing (44) overlies the hinge pin (32), which is free to move along its longitudinal axis (30). A cam follower (42) on the hinge pin (32) engages a cam (32) mounted to one of the hinge plates (22), so that the hinge pin (32) slides longitudinally as the hinge plates (22, 24) pivot relative to each other about the hinge pin (32). As the hinge pin (32) slides longitudinally, it axially compresses or decompresses the spring (48). The cam (32) is oriented such that pivoting of the hinge plates (22, 24) in either direction from an open position compresses the spring (48), providing a restoring force which tends to retain the hinge plates (22, 24) in the open position.

Tourville, Thomas↗

NASA NTRS2004

Seal ring installation tool

A seal ring tool that allows an installer to position a primary seal ring between hub ends of pipe flanges that are being assembled together. The tool includes a pivoting handle member and extension arms attached to the pivoting handle member. The ends of the arms have side indentation type longitudinal grooves angled toward one another for holding the primary seal ring in place between the hubs of respective pipes that are to be attached together. The arms of the tool can also have flat sides that can be used to abut against an optional second larger seal that is supported within a groove in one of the hub ends so that the second hub end can then be moved against the other side of the primary seal ring. Once the seal ring is positioned between the pipe hubs, the pipe hubs can be moved about the seal ring due to the flat sides of the arms of the tool. The tool eliminates the chances of damaging and contaminating seal rings being installed within pipe hubs that are being attached to one another.

Haselmaier, L. Haynes↗

NASA NTRS1979

Manual compactor

A manual compactor having two handles each pivoted at one end for movement through adjacent arcs toward and away from each other, such reciprocating activation motion being translated into rotary motion in a single direction by means of ratchet and pawl arrangements about the pivot shaft of each handle, and thenceforth to rotary motion of opposing screws one each of which is driven by each handle, which in turn act through ball nut structures to forcibly draw together plates with force sufficient for compacting, the handles also having provisions for actuating push rod within the handles for the purpose of disengaging the pawls from the ratchets thereby allowing retraction through spring loading of the plates and repositioning of the apparatus for subsequent compacting.

Stevenson, Grant E.↗

NASA NTRS1989

Space station wardroom table

A table top for use in constricted areas has a plurality of support arms abutting at one end to form a hub. The support arms are arranged in equidistant, spaced-apart relation to each other at the ends distal to the hub. A plurality of work surface leaf sections mounted between the support arms are individually pivotable through 360 degrees about their longitudinal axes. The table top additionally has a plurality of distal leaves, each distal leaf being attached to the distal end of one of the arms. The distal leaves are pivotable between an upright position level with the support arms and a stored position below the support arms.

Cohen, Marc M.↗