Showing papers on "Rotation published in 1977"

Passive ring resonator laser gyroscope

Abstract: A new method of measuring inertial rotation is presented. It is based on the use of a passive ring resonator as the rotation sensing element and an external laser for measuring the difference between the clockwise and counterclockwise lengths of the resonator. Preliminary performance data is included.

Theory of the rotation of the rigid earth

Abstract: An analytical theory is developed for the three axes of the triaxial rigid earth (the angular-momentum axis, the figure axis, and the rotational axis) A theory on rigid earth rotation will be important to one on a nonrigid earth, since the latter gives only the ratios between the amplitudes of rigid nutation and those of nonrigid nutation The present theory is characterized by the use of Andoyer variables, Hori’s averaging method, and a moving reference plane A comparison with Woolard’s theory shows that 1) the maximum difference in nutation of the angular-momentum axis, calculated from the same constants as Woolard adopted, reaches 00017; 2) the maximum discrepancy in Oppolzer terms is 0V0012: and 3) the present theory has no secular term either in the first power of time in the obliquity referred to the fixed ecliptic or in the angle between the figure axis and the rotational axis; both these secular terms appeared in Woolard’s theory and have an effect on the establishment of a reference system Nutation amplitudes as large as OOOOl are calculated for all three axes Use is made of Brown’s theory of the moon as improved by Eckert and of numerical values recommended at the working meeting of the International Astronomical Union held in Washington in September 1974 Any future revision of the lunar theory will not alter the values of the amplitudes of the nutational terms derived here

Satellite tracking antenna apparatus

Abstract: Satellite tracking apparatus for use on board ship as part of a maritime communications satellite terminal is disclosed. A directional antenna which is adapted to be trained in the direction of the satellite so as to be in communication therewith is mounted so as to be positioned about three axes, namely train, elevation, and cross-level axes. The mount also has a fourth axis which is parallel to or collinear with one of the other axes. This fourth axis may be a level axis which is movable with the antenna. A stable platform is movable with and rotatable about the level axis. Sensors on this platform provide outputs to servo controllers which rotate the antenna about the elevation and cross-level axes to maintain the platform stable. An azimuth sensor such as a gyro compass and sensors responsive to angular motion with respect to the train axis may also be mounted on the platform and provide outputs to a servo controller which controls the bearing or azimuth position of the antenna. An open loop control is provided for the level axis which establishes an equivalent angle between the stable platform and the true elevation line of sight (an angle equal to but opposite from the true elevation angle to the satellite). A mislevel is thereby created and sensed by the sensor for the elevation axis which provides an output that activates the elevation axis servo controller to reduce the mislevel to zero and null, thereby achieving the desired elevation of the antenna. The antenna is stabilized and decoupled from the motions (roll, pitch and yaw) of the ship and changes in the ship's heading, in that the sensors are mounted on the stable platform which moves with the antenna. The need for coordinate conversion computers responsive to sensors strapped down to the deck or other ship structure and for alignment of the antenna axes with the pitch or roll axis of the ship is also eliminated. The rotation of the antenna about its boresight axis is eliminated; thus avoiding misalignment between the polarization of the antenna and the satellite signals.

Apparatus for cutting vegetation

Abstract: An improved apparatus for cutting vegetation which is especially adapted to be employed with units having a top mounted gasoline motor interconnected by a drive tube to a lower rotating cutting head. An accessory handle is carried adjacent the motor. A housing carried on the lowermost drive tube encloses bearings and provides a journal for the cutting head. An actuator housing bolts to the housing and interfits for rigid support. A mechanical line feeder on the cutting head is operated by an actuating lever carried on the accessory handle through an interconnecting control cable. Reciprocation of the control lever operates the mechanical line feeder so that a predetermined length of cutting line is extended from the cutting head during rotation without interrupting cutting.

Rotation histories of the natural satellites

Abstract: Recent advances in the theory of rotation are combined with traditional approaches to study the rotational evolution of the 33 known natural satellites. A calculation similar to that reported by Burns and Safronov (1973) is applied to each satellite to obtain the characteristic time of decay of any wobble motion to smooth rotation about the principal axis of maximum moment of inertia. Stability criteria and capture probabilities are calculated for the 3/2 spin resonance. Results show that only the regular satellites and Iapetus, Hyperion, Triton, and the moon are tidally evolved. Of these, 13 have confirmed synchronous rotation periods; capture probabilities into the 3/2 resonance indicate that none of the remaining 10 should be captured in nonsynchronous, commensurate spin states. For the most part, the irregular satellites retain their original spins except for a relaxation to principal axis rotation. Tidal evolution of the obliquities of the satellites is evaluated in the framework of the generalization of Cassini's laws for the moon. Nearly resonant, forced librations in longitude of 4.8 and 0.5 deg are calculated on the basis of the observed shapes of Phobos and Deimos, respectively.

The effects of differential rotation on the splitting of nonradial modes of stellar oscillation

Abstract: The problem of the splitting of adiabatic nonradial modes of stellar oscillation owing to slow differential rotation is examined. Integral expressions for the frequency splitting are derived for the case of cylindrically symmetric rotation, and, for a particular rotation ''law,'' the results are applied to cooling white dwarfs and upper-main-sequence stars.

System for the obtainment and the regulation of energy starting from air, sea and river currents

Abstract: A system for obtaining and regulating energy from the air or sea and river currents includes a cyclone converter formed by three concentric rotating bodies, either on shafts or cylindrical rails or the like. Fixed rollers or other electromagnetic systems permit the rotation of the group around an imaginary or actual geometrical shaft. The outside body is self-orientating with its main components and deflectors on rotating components or a base sliding rail. The intermediate concentric body or turbine is formed by rings and vanes and a system of rollers or electro-magnetic supports which are inside or outside the turbine. The inside body or diffuser rotates concentrically in a reverse direction to the turbine and has vanes of opposite complementary angles.

Centrifugal blood processing system

Abstract: A centrifugal blood processing system is disclosed having a rotor drive assembly that is rotatably mounted to a stationary base for rotation along a predetermined axis. A rotor assembly, which includes a blood processing chamber, is rotatably mounted with respect to the base for rotation about the axis. A flexible umbilical cable segment is provided for establishing fluid communication with the blood processing chamber. One end of the cable segment is fixed with respect to the base along the axis at one side of the rotor assembly while the other end of the cable segment is attached on the axis in rotationally locked engagement to the rotor assembly. Guide means are provided for causing the umbilical cable to rotate about the axis with the motor drive assembly. Means are provided for rotating the rotor assembly and the rotor drive assembly in the same direction with a speed ratio of 2:1 to prevent the umbilical cable from becoming completely twisted during rotation of the rotor.

Method and apparatus for fastener tensioning

Abstract: A fastener tensioning method and apparatus for obtaining a desired degree of tension in a fastener. The apparatus includes a means for applying rotation to a fastener, a means for measuring the torque applied by the means for rotating the fastener, a means for determining a rate of change of torque applied to the fastener with respect to the rotation applied to the fastener, a means for detecting when the rate of change of torque with respect to rotation becomes a constant, a means for accomplishing a desired amount of rotation of the fastener beyond the rotation required to achieve the constant rate of change of torque with respect to rotation, and a means for shutting off the means for applying rotation to the fastener in response to the total desired rotation being achieved. The embodiment herein described improves the well-known "turn of the nut" method for fastener tensioning by providing that method with a well determined starting point.

Step assembly for vehicle

Abstract: A power operated step assembly providing an auxiliary step adjacent the doorway of a vehicle. A box frame is secured to vehicle support structure below a doorway open to the interior of the vehicle. A step unit is movably connected to the box frame with two pair of parallel links. A transverse rod mounted on the frame is secured to one link of each pair of links so that the links are rotated in response to rotation of the rod. A power unit comprising a reversible electric motor and a lead screw carrying a nut is attached to the frame and crank arms connected to the rod. A step unit having a transverse platform pivoted to the lower ends of the links is selectively moved to an out step position and an in upper storage position in response to operation of the reversible electric motor.

Tomographic apparatus for producing transverse layer images

Abstract: In an illustrated embodiment a plurality of x-ray sources are arranged at equal angles about a rotating frame. Each source and detector arrangement may provide the desired number of measurements such as 240, so that the required angular movement for scanning is reduced by a factor corresponding to the number of sources. In one embodiment with three sources and 240 detectors for each source, the desired number of measured values may be obtained by rotation through 120 degrees instead of 360 degrees. In another illustrative embodiment, the narrow beam from the x-ray source covers about 30 detectors, the beam and detectors being linearly scanned so as to generate about 240 measurements, there being three source-detector arrangements separated by 60 degrees, so that scanning is carried out by rotation through 60 degrees rather than 180 degrees.

Cartridge and flexible magnetic disk assembly

Abstract: A thin flexible magnetic disk rotatably disposed in a cartridge of rigid material and protected thereby. The disk is loosely mounted on a driving hub assembly and has an arrow shaped center hole surrounding a central round hub portion of the hub assembly. A drive pin is carried by the hub assembly and extends loosely through a corresponding hole located in the disk and spaced from the center of the hub assembly and located on a radial line preferably of about 90 degrees with respect to a radial line passing through the apex of the straight hole edges forming the arrow so that the disk is automatically centered on the hub assembly due to any restraint on the disk during its rotation.

Streamline Curvature Effects on Turbulent Boundary Layers

Abstract: A theoretical tool has been developed for predicting, in a nonempirical manner, effects of streamline curvature and coordinate-system rotation on turbulent boundary layers. The second-order closure scheme developed by Wilcox and Traci has been generalized for curved streamline flow and for flow in a rotating coordinate system. A physically based straightforward argument shows that curvature/rotation primarily affects the turbulent mixing energy; the argument yields suitable curvature/rotation terms which are added to the mixing-energy equation. Singular-perturbation solutions valid in the wall layer of a curved-wall boundary layer and a fully developed rotating channel flow demonstrate that, with the curvature/rotation terms, the model predicts the curved-wall and the rotating coordinate system laws of the wall. Results of numerical computations of curved-wall boundary layers and of rotating channel flow show that curvature/rotation effects can be computed accurately with second-order closure.

Entry control device

Abstract: An entry control device is provided for controlling the entry of a preselected document, such as a coded credit card into a dispensing machine wherein various checking and dispensing functions are performed as a result of the information obtained from the coded card. The control device includes a housing having an entry passage therein for receiving and orienting the preselected document for transport into the dispensing system. A gate is pivotally mounted to the housing for pivotal movement between a closed position for barring entry of the document into the dispensing system and is rotatable to an open position by insertion of the document into the entry passage of the housing. A trigger is pivotally mounted to the housing for movement between first and second positions. The trigger extends into the entry passage and is disposed adjacent the gate. The device further includes a locking lever pivotally mounted to the housing and the trigger for movement between a locked position and an unlocked position corresponding to the trigger first and second positions. Engagement of the document with the trigger rotates the locking lever from the locked position to the unlocked position to cause the trigger to rotate from the first position to the second position, thereby causing rotation of the gate from the closed position to the open position to allow entry of the document into the dispensing system. Disengagement of the document with the trigger causes rotation of the gate from the open position to the closed position.

Friction heat space heater

Abstract: A furnace or space heater is operable at low cost by a small electric motor which rotates an elongated cylindrical drum on a vertical axis, within an elongated cylindrical casing at a clearance of about one eighth of an inch in the annular chamber formed therebetween A supply of light lubricant normally occupies the lower portion of the annular chamber but rises to fill the chamber during rotation of the drum The casing is enclosed in a housing, having a fan chamber containing an electric motor and fan or blower The motor shaft may rotate both the fan and the drum

Variable camber trailing edge for airfoil

Abstract: An airfoil having a support frame, a trailing edge end section, and upper and lower variable camber skin sections extending rearwardly from the support frame to the trailing edge end section. A walking beam is positioned between the upper and lower variable camber skin sections, and comprises a forward positioning section and a rearwardly extending locating arm. The positioning section is connected to the lower swing ends of two pivot links which extend upwardly and convergently toward one another to connect to the pivot frame at spaced locations so that forward or rearward movement of the positioning section causes the locating arm of the walking beam to rotate, respectively, downwardly or upwardly. A trailing edge beam is connected by its forward end to the support frame and by its rear end to the trailing edge end section, with the trailing edge beam being connected at an intermediate portion thereof to the rear end of the locating arm of the walking beam. Thus, downward or upward rotational movement of the locating arm of the walking beam causes a corresponding downward or upward rotational movement of the trailing edge end section of a correspondingly greater degree of rotation, relative to the locating arm.

Moving‐load stability of a circular plate on a floating central collar

Abstract: The eigenvalue problem and transverse response of a circular plate, that is free at the periphery and that slides freely along the axis of symmetry without bending rotation, are theoretically analyzed. The occurance of eigenvalues in the boundary conditions is accounted for with an extended operator definition in the equation of transverse motion. The stability of these plates under concentrated loads moving at uniform speed is analyzed for (i) harmonic transverse loading and (ii) loading proportional to transverse displacement and velocity. The harmonic loading case leads to a classical, critical‐speed analysis. The proportional loading case represents the excitation of the plate by transverse position guides. The number, orientation, and mechanical properties of the guides determine the transverse stability of the plate‐guide dynamic system.

Limited rotation motor

Abstract: A limited rotation motor has a stator and a rotor mounted for limited rotation relative to the stator. The stator is constructed to conduct bias flux through magnetic circuits that extend across air gaps between the stator and the rotor and a drive system produces drive flux which is conducted through magnetic circuits that extend across air gaps between the stator and rotor to drive the rotor. The stability of radial rotor position in its support bearings is enhanced by an imbalance in the bias flux magnetic circuits which continually produces a resultant radial force on the rotor so that a well defined radial position of the rotor is maintained over the range of limited rotation that the rotor moves in response to the drive system.

Tape cassette holder

Abstract: A holder for the storage, handling, and filing of sound recording magnetic tape cassettes which is an integral tray-shaped frame, includes a support beam disposed along its upper edge and an index bar extends upwardly of the beam and serves as a handle for the holder. A rectangular base or back panel depends from the lower edge of the support beam and side walls extend outwardly of the marginal edges of the base panel. Spaced posts extend upwardly of the base panel and are adapted to engage and prevent rotation of the reels of said cassette. A resilient retaining flange or tab extends from one of the side walls in spaced parallel relationship to the base panel for releasably gripping a cassette. The base panel is provided with an aperture disposed opposite the retainer tab to accommodate therein a raised land portion of the tape cassette.

Combination work table and vise

Abstract: A combination work table and vise. The work table is vertically adjustable and has a tiltable work platform which is tiltable about a longitudinal axis so as to provide a sloped working surface. The tiltable work platform also reduces the dimensions of the work table for transportation and storage. The work platform includes at least two leaves, at least one of which can be moved laterally relative to the other to provide a vise action between the leaves. Lateral leaf movement is accomplished by means of a hand crank and screw combination. The hand crank is rotatably mounted to a first leaf while the screw is threadedly engaged in a swivel block mounted to a second leaf. Rotation of the hand crank moves at least one leaf relative to the other and thereby accommodates clamping a workpiece between the two leaves in an action similar to the jaws of a vise. The swivel accommodates asymetrical, lateral movement of the second leaf thereby accommodating clamping of a nonsymetrical object between the two leaves. The hand crank may also be interconnected to a second swivel to provide both leaves with asymetrical lateral movement.

Counterweighted blade damper

Abstract: A segmented damper is provided with a lower dovetail portion which is insertable into a dovetail slot for radial retention and which is engageable on its face by a blade retainer for axial retention, such that the damper is pivotable in an axial plane. The damper upper portion has on its one side a flange for engaging the blade shank rail and on its other side a flange for shifting the damper center of gravity axially outward from the lower pivot point. Centrifugal force, occasioned by rotation of the disk and damper, then causes the damper to pivot and impart an axial force against the blade to thereby dampen vibrations.

Vertical blind controls

Abstract: Vertical blinds having commonly housed and traversely movable controls for controlling the traverse and rotation of the vanes are disclosed. In a disclosed embodiment, the vanes are supported by carrier members, and a rotation rod extends through the carrier members. The carrier members are slideable along the rotation rod. A control assembly is mounted to slide along and also rotate the rotation rod. Sliding of the control assembly along the rotation rod slides the carrier members to thereby traverse the vanes, and actuation of the control assembly rotates the rotation rod and the vanes. The control assembly includes meshing bevel gears, one of which is coupled to an actuating rod or wand and the other to the rotation rod whereby rotation of the wand causes rotation of the vanes. The control assembly is slid by means of the wand which is universally connected to the control assembly. The wand is thus a unitary control for actuating both traverse and rotation of the vanes.