Showing papers on "Rotation published in 1974"

Series redundant drive system

Abstract: Disclosed is a plurality of motors mechanically connected in series so as to provide operational redundancy. The shaft of a given motor is rigidly attached to the housing of the next motor in the series, so that rotation of the first shaft will cause the second motor and its shaft to rotate. Means are provided to prevent relative rotation of the rotors of the redundant motor(s). Other means are provided to detect failure of the operating motor and to activate another motor in the series when this occurs.

Hydromechanics of low-Reynolds-number flow. Part 1. Rotation of axisymmetric prolate bodies

Abstract: The present series of studies is concerned with low-Reynolds-number flow in general; the main objective is to develop an effective method of solution for arbitrary body shapes. In this first part, consideration is given to the viscous flow generated by pure rotation of an axisymmetric body having an arbitrary prolate form, the inertia forces being assumed to have a negligible effect on the flow. The method of solution explored here is based on a spatial distribution of singular torques, called rotlets, by which the rotational motion of a given body can be represented. Exact solutions are determined in closed form for a number of body shapes, including the dumbbell profile, elongated rods and some prolate forms. In the special case of prolate spheroids, the present exact solution agrees with that of Jeffery (1922), this being one of very few cases where previous exact solutions are available for comparison. The velocity field and the total torque are derived, and their salient features discussed for several representative and limiting cases. The moment coefficient C[sub]M = M/(8[pi][mu][omega sub 0]ab^2) (M being the torque of an axisymmetric body of length 2a and maximum radius b rotating at angular velocity [omega], about its axis in a fluid of viscosity [mu]) of various body shapes so far investigated is found to lie between 2/3 and 1, usually very near unity for not extremely slender bodies. For slender bodies, an asymptotic relationship is found between the nose curvature and the rotlet strength near the end of its axial distribution. It is also found that the theory, when applied to slender bodies, remains valid at higher Reynolds numbers than was originally intended, so long as they are small compared with the (large) aspect ratio of the body, before the inertia effects become significant.

A Note on Modifications to the Givens Plane Rotation

Abstract: It has recently been shown how to perform plane rotations without square roots and with a saving in multiplications. (See for example, Gentleman, 1973). The purpose of this note is to present the method in a simple but general manner which also suggests other modifications. c = cos 6 and s = sin 6. The standard Givens plane rotation is of the form X = X' where putting d={xl+y\\)i (1.1) we have c = xjd, s = yjd (1.2) and xi = d (1.3) Yi =-i Since each column of X' requires four multiplications this is referred to as a four multiplication transformation. If we denote the computed x-and y\\ by x[ and y' t respectively then Wilkinson (1965) has shown that for f-digit floating point arithmetic 2 2 2 Ji\\ (i.5) where |a,| < 5. 2~',j = 1, 2, 3,4. Since \\c\\, \\s\\ < 1 this means that the transformation is stable.

Apparatus for making non-woven fibrous sheet

Abstract: An improved apparatus for use in making nonwoven fibrous sheets of organic synthetic polymers includes a spinneret orifice through which a polymer solution is flash spun to form a plexifilamentary strand directed in a generally horizontal direction toward a rotating baffle whose axis of rotation is generally parallel to but spaced from the axis of the extrusion orifice and whose surface is contoured so as to simultaneously spread said strand into a planar web, direct the web into a generally vertical plane downward toward a collecting surface, and cause said web to oscillate in the plane as the baffle rotates. The improvement consists of an aerodynamic shield of specified configuration. The shield terminates at an edge which lies substantially along an arc of a circle whose center lies on the axis of rotation of the baffle. Since the plexifilamentary strand impinges on the baffle at a point near its axis of rotation and is deflected as a web which therefore oscillates through various radial directions within the plane substantially perpendicular to the rotation axis, only the specified shield configuration will provide flow paths of approximately equal impedance, independent of the instantaneous radial direction at which the web leaves the baffle.

Tire inspection apparatus

Abstract: There is disclosed a method and apparatus for rapid and convenient dimensional inspection of a tire. The method involves mounting the tire for rotation and impinging on its tread surface, a laser beam, analyzing the backscattered radiation to determine the position in space of the point of impingement and selectably scanning or positioning the laser to measure various positions on the tire surface. The apparatus includes the laser device, a mounting unit for the tire to be inspected and another mounting unit for the laser gauge. The first mounting unit permits rotation or angular indexing of the tire. The second mounting unit permits four separate gauge motions: radial or circular scan across the tread surface, lateral scan across the tread surface, rotation of the plane containing the laser beam and the backscattered beam and spacing normal to the axis of tire rotation. The former two motions are motor controlled, the latter two are manually controlled.

Fluid Forces on a Body in Shear-Flow; Experimental Use of 'Stationary Flow'

Abstract: The lift and drag forces have been measured on a sphere and a transverse cylinder immersed in an open liquid shear-flow and situated close to the lower, frictional, boundary (the bed). Two conditions were investigated: ( a ) that of zero drag, when the body was drifting with the flow, and ( b ) that when it was held against the flow. In condition ( a ) the body could be either allowed to rotate about a transverse axis subject to unavoidable pivot friction, or prevented from rotating. Marked difference was found in the magnitude of the lift force according to the applied resistance to rotation. The lift force was a maximum when rotation was prevented and small or undetectable when free rotation was allowed. In the conditions ( a ) and ( b ) the lift force decreased with increasing clearance between body and boundary, to zero when the clearance exceeded approximately one body diameter. In condition ( b ) lift, i. e. normally repulsive, forces of approximately equal magnitudes to those below were exerted as the body approached the upper free liquid surface. In the drifting condition ( a ) the considerable difficulties of observation and force measurement when a body is moving with the flow were removed by the use of a backward-moving bed boundary. By thus superimposing a reverse velocity on the whole system, the mean fluid velocity at any desired distance from the boundary can be made zero relative to the observer without appreciably affecting the internal dynamics of the flow. This device also permitted the repetition of the measurements made by using liquids of greater viscosity than water available in limited quantities. The results are interpreted with an explanation in mind of certain aspects of the motions of unsuspended solids in saltation over a stream bed.

Electric rotating machine

Abstract: An electric rotating machine including a rotor-stator device having a permanent magnet symmetrical rotor and a stator structure. The stator is in capsule form and has a pair of pole pieces and a magnetic flux transmitting structure for transmitting flux to the pair of pole pieces. The flux transmitting structure includes a pair of support members between which the rotor and stator structure are supported. The rotor is journaled for rotation in the support members. A rotatable gear assembly is supported on at least one of the support members and spaced from the rotor and stator structure to provide selective speeds in response to the rotation of the rotor. In one described embodiment the magnetic flux transmitting structure may comprise a generally U-shaped structure.

A method for the separation of true polar wander and continental drift, including results for the last 55 m.y.

Abstract: Continental drift and true polar wander are distinguished. If any true polar wander has occurred, it would appear as a rigid rotation of the lithosphere relative to a fixed spin axis. A mathematical method is proposed to decompose a general displacement field on a sphere into two parts: a part due to a rigid rotation and a remaining part of random motions. The rigid rotation found is the one that best fits the observed displacement field in a least squares sense over the surface of the earth. The random motions, which are separated from the rigid rotation, are then ascribed to continental drift. Formulas are developed that give the Euler angles of the best-fitting rotation in terms of the observed plate displacements for the case of small displacements. These formulas for the Euler angles are also expressed in terms of the first-order spherical harmonic coefficients of the potential generating the displacement field. The proposed method is applied to three theoretical displacement fields having an analytic expression to illustrate the decomposition of specific fields. The displacement field of the plates is constructed for the time period since the early Tertiary, and the method is applied to determine the amount, if any, of true polar wander. The best-fitting rotation, or true polar wandering, was found to be only 2°, an amount less than the uncertainty (4°) of the mean paleomagnetic pole used.

Area distortion in narrow beam rotation radiography.

Abstract: The distortion of morphologic object elements, for distortion, at the exposure of a panoramic image has been determined mathematically and experimentally. As models the square, the circle, the rhomb, and the equilateral triangle were used. The general characteristics of the form distortion in narrow beam rotation radiography are analysed and described.

Rigid and differential rotation of the solar corona

Abstract: The rotation of the solar corona has been studied using recurrence properties of the green coronal line (5303 A) for the interval 1947–1970. Short-lived coronal activity is found to show the same differential rotation as short-lived photospheric magnetic field features. Long-lived recurrences show rigid rotation in the latitude interval ±57°.5. It is proposed that at least part of the variability of rotational properties of the solar atmosphere may be understood as a consequence of coexistence of differential and rigid solar rotation.

A Mathematical Model of Narrow Beam Rotation Methods

Abstract: The first suggestions that a rotating narrow beam might be used to obtain special radiologic projections were put forward by VALLEBONA (1930) and HECKMANN (1939). A method for exposing panoramic images of the jaws, using a rotating beam, was developed from the works presented by PAATERO (1949, 1954), and is today in wide use in odontologic roentgen examinations. PAATERO'S method, 'pantomography', was presented as a modified form of tomography adapted for application to a curved layer, and the mathematical analyses of the method presented up to now have been based on this premise (HUDSON et colI. 1957, DUHAMEL 1954, 1957, SOILA 1961, TAMMISALO 1964, T AMMISALO & NIEMINEN 1964). DUHAMEL (1957) maintained that the image is composed of a series of tomograms whose widths correspond to the width of the beam. The principle underlying the methods based on a rotating narrow beam differs fundamentally from that of true tomography however. WELANDER & NYSTROM (1971) have demonstrated empirically that the rotating slit methods create an imaginary focus at the rotation centre of the beam; this 'rotation focus' constitutes the source of the rays in a central projection. The blurring and

Automatic welding apparatus

Abstract: An automatic welding apparatus comprising a workpiece fixture carried by a moving member for rotation about a horizontal axis extending in a back and forth direction, said moving member being provided on a carriage for sliding movement in a lateral direction, said carriage being provided for sliding movement in said back and forth direction, and a torch fixture carried by an arm for rotation about a vertical axis, said arm being provided for sliding movement in the vertical direction. In another embodiment, the workpiece fixture is provided only for rotation about a horizontal axis extending in the back and forth direction, and the torch fixture is carried by the arm for rotation about the vertical axis, which arm is provided at the end of a column for sliding movement in said lateral direction, which column is provided on a sliding member for sliding movement in the vertical direction, which sliding member is provided on a guide for sliding movement in said back and forth direction. The movement of these components is controlled in an electronic manner in accordance with a preset, i.e. predetermined data. The degree of freedom of the movement of the workpiece and torch is thus divided into both workpiece and torch fixtures and as a result welding a workpiece of complicated shape is possible in a better attitude of the torch and the workpiece.

Apparatus for facilitating trailer hitch element alignment

Abstract: Apparatus for facilitating the substantially vertical alignment of a trailer hitch element carried by a moving draft vehicle with a trailer hitch element carried by a stationary trailer vehicle, including a device for linearly interconnecting, within the limits thereof, such trailer vehicle and such draft vehicle having a portion connected at an extremity thereof to the rear of such draft vehicle on the centerline thereof and having another portion thereof positioned above such trailer vehicle carried trailer hitch element interconnected with such trailer vehicle for rotation with respect to a substantially vertically disposed axis passing substantially centrally through such trailer vehicle carried trailer hitch element. The apparatus also includes a mirror positioned above such device for linearly interconnecting, within the limits thereof, such trailer vehicle and such draft vehicle and similarly rotatable therewith about such substantially vertically disposed axis, such mirror facing towards the rear of such moving draft vehicle to afford the operator thereof a reflected view of at least a portion of such trailer vehicle carried trailer hitch element as well as with a reflected view of at least a portion of such device for linearly interconnecting, within the limits thereof, such trailer vehicle and such draft vehicle. The apparatus further includes an indicator element positioned above such mirror and viewable thereover under certain circumstances although preferably facing in a direction opposite the direction in which such mirror faces; such indicator element also being similarly rotatable with respect to such substantially vertically disposed axis together with such mirror and with such device for linearly interconnecting, within the limits thereof, such trailer vehicle and such draft vehicle.

The compensation for movement-produced changes of object orientation*

Abstract: When one moves forward, one views objects to the side of one’s path successively from different directions. In the mover’s visual field, such objects change their orientation; relative to him they undergo a partial rotation. Although this rotation is given in several ways, it is hardly ever perceived. This is due to a compensating process that takes O’s change in position relative to the object into account. We demonstrated the existence of this compensating process and measured the accuracy with which it operates by means of a device that made an object turn in response to O’s position change so that the normal rotation of a stationary object relative to the moving O could be augmented or diminished to various degrees.

Panoramic photographic methods

Abstract: A panoramic photographic process which employs a photographic instrument having an objective lens with an optical axis, an aperture in front of the lens, and a film guide in back of the lens for travel of film therealong. The method comprises advancing the film along the guide at a predetermined rate of speed, while rotating the instrument about an axis passing through the lens and extending at an angle to the optical axis, the direction and speed of rotation of the instrument being such that the net velocity of travel of the film is substantially zero so that it serves as an instantaneous center of rotation thereby enabling the photographing of the panorama situated above the natural or artificial horizon.

Tightening method and system

Abstract: A tightening method and system for practicing same are disclosed herein for tightening a fastener to a desired axial load. According to the method, torque is applied to the fastener until it is tightened to its yield point and either the torque applied at the yield point or the angular rotation of the fastener at the yield point are determined and are used to determine the axial load acting on the joint assembly and these determined characteristics are used to determine either the torque or angular rotation required to tighten the fastener to the desired load. Thereafter, torque is again applied to the fastener and when the actual torque being applied or actual angular rotation of the fastener substantially equals that required to tighten the fastener to the desired load, the application of torque is discontinued. The tightening system disclosed for practicing the method includes a wrench for applying torque to a fastener and including means for developing a signal representative of the torque applied to or angular rotation of the fastener and means for developing an actuating signal when the fastener has been tightened to its yield point. The actuating signal shuts off the wrench and feeds the signal representative of torque or angular rotation at the yield point to a memory device including predetermined load-torque relationships or a predetermined load-angular rotation relationship for the fastener. From these relationships the torque or angular rotation required to tighten the fastener to the desired load can be determined and a signal representative thereof is developed and stored for comparison with a signal representative of the actual torque or angular displacement of the fastener as the wrench again applies torque to the fastener. When the compared signals are substantially equal, a control signal is developed for shutting off the wrench.

Reciprocating pedal drive mechanism for a vehicle

Abstract: A pedal drive mechanism for a are vehicle. In a preferred bicycle version, pedal lever arms Additional pivotally attached to each side of the frame near the rear wheel hub for reciprocal rotation within a limited angular sector. Downward forces exerted by a rider on the pedals are transmitted through flexible tension members on each side of the bicycle anchored either to first attachment points intermediate the ends of the lever arms or to second attachment points on the frame above the lever arms and leading around pulleys mounted at the other of the first and second points. From the pulleys each tension member leads over and around a corresponding rotary driving member that is connected through an overrunning clutch to the rear wheel. Means interconnecting the lever arms return one arm to the upper starting position while the other arm is in the downward power stroke. Manually operable control means vary the location of the first attachment points on the lever arms to change the torque delivered to the driving members for a given driving force on the pedals. Additional idler pulleys mounted at the tension member anchor points may be used to "gear up" the mechanism for higher speeds and lower output torque. Disconnect means disengage the overrunning clutches from the rear wheel hub to prevent damage to the mechanism when the bicycle is backed up.

Electronic run-out compensator and method of electronically compensating for wobble run-out in a rotating body

Abstract: Electronic means for compensating for the wobble run-out in a rotating body to determine the true plane of rotation which is perpendicular to the axis of rotation, whereby angular deviation between the axis of rotation and a reference axis may be determined. The electronic means operates on a method which electronically measures the amount of wobble between positions of the body 180* of rotation apart and performs the calculations for any one or a plurality of reference axes at the same time so as to compensate the readings for the run-out error.

Safety belt retractor locking device

Abstract: A vehicle acceleration sensitive locking device is disclosed for use with a conventional safety belt retractor having a shaft mounted ratchet. The locking device includes a pivotally mounted pawl normally spaced from the ratchet by a preselected distance and an inertial mass pivotally mounted to sense change in vehicle velocity above a level predetermined to be dangerous. Movement of the inertial mass displaces the pawl to its operate position to block rotation of the ratchet and the safety belt retractor shaft and, thereby, prevent protraction of the safety belt when the change in vehicle velocity exceeds the predetermined level. The device further includes adjustment means operative to limit movement of the pawl away from the ratchet when the pawl is in its inoperative position to determine the normal spacing between said pawl and ratchet.

Rotary piston mechanism

Abstract: A rotary piston mechanism for internal combustion engines, fluid motors, pumps and the like has an outer body enclosing a chamber that is defined by three equal curvilinear walls that circumscribe the chamber axis and define an equilateral triangle in a plane perpendicular to the chamber axis, the walls being convex with respect to the axis, and a generally elongated rotor confined in the chamber of length equal to the span of the chamber along a bisector of any of the angles of the equilateral triangle defined by the chamber walls, the rotor being pivotally supported to rotate about a rotor axis which is parallel to the chamber axis and moves around the chamber axis over a closed path, the sense of rotation of the rotor on the rotor axis being opposite to the sense of rotation of the rotor axis around the chamber axis.

Door opening and closing apparatus for tumbling barrel

Abstract: A rotatable barrel for the surface treatment of particulate matter enclosed therein including a generally round perforated barrel with end elements. An opening is provided in the side for the insertion and discharge of particulate matter and a door for opening and closing said opening is mounted on lever arms to swing in an arc between open and closed positions. The lever arms are mounted on hubs extending from the ends of the barrel along its axis of rotation and are mechanically, rigidly attached to gears spaced from the ends of the barrel. A limitation is placed on the arc through which the door may swing relative to the barrel; stop means are provided both adjacent one edge of the opening and remote from the other edge of the opening whereby the door may swing into closed position in abutment with the one stop means adjacent the opening and may swing completely out of the opening into engagement with the other stop means. The door serves as the driving mechanism for turning the barrel in response to the direction of gear rotation.

Self-propelled vehicle

Abstract: A self-propelled vehicle includes a vehicle body mounted on a frame and rollably supported by front and rear wheel assemblies, driving means, such as an engine, mounted on the frame for powering the vehicle, a mechanism for drivingly connecting the output of the drive means to at least one of the wheel assemblies, a mounting device for connecting rotatably the driven wheel assembly to the body to permit the driven wheel assembly to rotate freely about an axis in a 360 degree circle of rotation, and a manually operable steering control device rotatably mounted on the frame for rotating the driven wheel assembly about its axis in the 360 degree circle of rotation, whereby the vehicle may be driven in a reverse direction by simply turning the driven wheel assembly through 180 degrees and then applying the power to drive the vehicle in reverse. A ramp is hingedly mounted on the body to serve as a loading ramp when in its down position and to serve as a closure when disposed in its upper position, and a latching mechanism maintains the ramp in its upper position and serves as a wheel brake when the ramp is in its lower position. A flexible coupling is provided between the steering control device and the driven wheel assembly to enable the steering control device to extend upwardly and rearwardly to terminate in a convenient position for manipulation by the operator.

Sub-sea pipe cleaning apparatus and method

Abstract: Apparatus and method for cleaning the exterior surface of a pipe such as a pipe located in a sub-sea location having a coating of concrete or the like thereabout. The apparatus includes a generally longitudinal frame which supports a carriage for longitudinal traverse therealong. The carriage supports a high-pressure fluid nozzle which is arranged to direct the discharge thereof against the pipe coating which is to be removed. The carriage is arranged for longitudinal traverse along the frame, to thereby direct a high-pressure fluid stream into contact with the surface of the pipe. The frame is also arranged for rotation about the pipe, whereby a section of the pipe can be cleaned about its full circumference by a number of generally longitudinal runs along the pipe section being cleaned. The carriage may also support a wire cutter for cutting any re-enforcing wire after the concrete has been dislodged by the fluid nozzle. A pipe-cutter may also be attached to the apparatus for making a circumferential cut or cuts to remove a damaged section of pipe. The apparatus may be raised and lowered in a body of water to and from the cutting or cleaning position by a buoyancy tank attached thereto which is arranged to either raise or lower in a body of water in response to changes in the buoyancy factor of the tank, which may be controlled from the surface, for example.