Abstract: A system for controlling the movement of a movable member with respect to a stationary member, such as is found in a vibration welding apparatus. The system may include a force controller that converts desired force command signals into desired flux command signals and a flux controller that controls the flux in a magnetic core of the stationary assembly to effect the desired movement of the movable member. The stationary assembly may include a plurality of magnetically uncoupled E-cores of paramagnetic material.

Abstract: The present invention relates to a method for switching over the current between successive stators of a railway system comprising a track and a vehicle and with a long-stator linear motor. The method according to the present invention proceeds from a conventional double-infeed step-change method. During the switching over of the current from one stator section of a long-stator winding phase to the following one, the section cable, which is assigned to the stator sections to be changed over and is supplied with power from two substations by double infeed, is split up. In this way, the sections to be changed over can be supplied by single infeed by a single substation in each case. It is possible thereby to avoid the unilateral loss of thrust which occurs in the case of conventional step-change methods.

Abstract: In a linear-motor-driven transport installation, in particular a linear-motor-driven simultaneous stretching installation, the tenter-clip carriage return section (10) is divided into at least three zones, namely a first speed-changing zone (17), a following transporting zone (19) and a subsequent braking zone (21). The length of the speed-changing zone (17) and the braking zone (21) is together less than 40% of the overall length of the return section (10). Only in the speed-changing zone (17) and/or braking zone (21) are more powerful drive devices provided than in the other part of the return section (10), in order to subject the carriages there to a more intense change in speed.

Abstract: An electromagnetic drive system having an integrated position signal generation for use by the drive windings for the movement and power generation and as a measuring system for determining the position of the movable partial system of the drive with respect to the stationary system, so that separate measuring systems are generated. The drive system including a stationary drive coil system of a direct current linear motor, having at least two identical partial coils which are serially connected with each other induced with a pulse length modulated control signal with a constant pulse frequency and a constant circuit voltage. For the position measurement, the impedance change in the partial coils of the coil system is picked up in accordance with the principle of an inductive voltage splitter by establishing the slopes of the electric voltage paths on the partial coils at a constant point in time after switching over the pulse length modulated control signal.

Abstract: A linear motor includes a single-phase coil, a plurality of polyphase coils each of which is shorter than the single-phase coil and wound to be parallel to the single-phase coil, a first permanent magnet movable relative to the single-phase coil and the plurality of polyphase coils in an axial direction of the single-phase coil, a first yoke consisting of a ferromagnetic substance and extending through the single-phase coil in the axial direction, a second yoke consisting of a ferromagnetic substance and having, outside the single-phase coil, a portion arranged to be parallel to the first yoke, to form a closed magnetic circuit together with the first yoke and the first permanent magnet such that the closed magnetic circuit circulates magnetic fluxes from the first permanent magnet across a winding of the single-phase coil, and a second permanent magnet for connecting the first and second yokes.

Abstract: A positioning apparatus includes a movable stage, a first linear motor for moving the stage in a predetermined direction, a platform for supporting the first linear motor, and an inertial force application mechanism for applying a force for canceling a force acting on the platform, which is generated when the stage is moved by the first linear motor. The inertial force application mechanism includes amass body, a guide for supporting and guiding the mass body, a second linear motor for moving the mass body, and a controller for controlling the second linear motor. Since the inertial force application mechanism of the positioning apparatus prevents transmission of vibration generated by an increase in an exciting force of the stage, rapid and precise positioning can be performed.

Abstract: An improved control device for linear-motor-driven equipment, in particular for the drive of tenters of a film stretching plant, has a central control device (1) and a multiplicity of converters (11) that are activated thereby, at least indirectly. An improvement is achieved by a phase profile, which describes a relationship between the phase angle, the current amplitude and a clock pulse, for activating the stator winding (7) in a relevant zone (5), being able to be predefined for the converters (11), and by the corresponding phase-profile data for the activation of the stator winding (7) being able to be calculated and/or generated in the converters (11). In addition, a synchronization device, via which the time signals in the converters can be synchronized with one another during operation, is provided.

Abstract: A linear actuator is used to push a spring-loaded ram The loading force of the spring against a stationary workpiece is calibrated with the displacement of the ram once the load exceeds the spring preset value. At a preset loading position, an electrical contact opens, indicating that the spring load has reached or exceeded the preset value. A mechanical stop, acting in conjunction with the stall characteristics of the linear actuator, prevents the operating range from being exceeded. This device has applications where precise standoff from a surface, the application of a precise force to that surface, and a controlled rate of the application of the force is needed.

Abstract: A linear motor path forms a closed figure. Contactless power control and position feedback permit a linear motor stage to traverse the closed figure without interference from trailing wires. One embodiment of the closed figure includes a racetrack pattern with straight runs joined by curved ends. Axes of armature windings are skewed to lie across the path in the curved ends to maintain force on the linear motor stage. Other embodiments of the invention includes multilevel paths wherein one portion of the path crosses over another portion of the path. Disclosure is made of a linear motor stage supported below the path by magnetic attraction between permanent magnets on the stage and magnetic material in the path.

Abstract: A linear motor having motor magnets on a movable stage, also includes non-interleaved armature windings on a path. The magnets are arranged m along the span A of the movable stage. The armature windings are arranged with n windings occupying a distance equal to the span S. A switching device automatically switches power on to the armature windings entering the span, and switches power off to the windings leaving the span. The switching is done when the a magnet is aligned with the coil whose power is being switched on or off in order to minimizes switching noise. Switching is conveniently done using Hall effect devices controlling the switches, and a switching magnet, movable with the stage, having a length equal to the span. As the switching magnet comes within magnetic interaction distance of a Hall effect device, the Hall effect device closes its associated switch.

Abstract: A linear motor apparatus includes a mover, a stator, a detector, and a driver. The mover is adapted to be shifted along a shifting direction, and has a predetermined magnetic flux distribution. The stator has a plurality of coils aligned along the shifting direction of the mover. The detector detects the relative position of the mover with respect to the stator. The driver excites two or more coils simultaneously based on a predetermined target value and the output of the detector.

Abstract: A motor controller produces independent first and second drive power signals for independent application to first and second linear motor stages movable on the same path. Each armature winding in the path is connected to a first switch receiving the first drive power and to a second switch receiving the second drive power. A first switch control device associated with the first linear motor stage actuates the first switches in its vicinity, while leaving the remaining first switches unactuated. A second switch control device associated with the second linear motor stage actuates the second switches in its vicinity, while leaving the remaining second switches unactuated. Each linear motor stage has an encoder associated with it to inform the motor controller of its position and/or motion.

Abstract: A linear motor comprising a DC magnetic field of alternating polarity arranged in a longitudinal axis, a coil assembly located substantially in a plane parallel to and immersed in the alternating magnetic field, said coil assembly containing individual coil loops of essentially rectangular shape and having end turn areas arranged parallel to said longitudinal axis of the magnet field and coil side areas being perpendicular to said longitudinal axis of the magnetic field with each coil side having a coil side width CSW) and each coil loop having a coil outside width (COW) and coil inside width (CIW) such that COW=CIW+(2.times.CSW) wherein the coils have a coil outside length (COL), forming a coil assembly area (CAA) approximately equal to COW.times.COL and said coil assembly has a coil assembly thickness (CAT) in a direction creating a coil assembly volume (CAV) approximately equal to the coil assembly area (CAA) times the coil assembly thickness (CAT) pursuant to the following equation: CAV.apprxeq.CAT.times.

Abstract: A linear motor includes a coil unit, and a movement unit including a magnetic planar body facing against the coil unit, wherein a changeable clearance .delta. is formed between the magnetic planar body and a plurality of lamination core protrusions in the coil unit, and a nonmagnetic planar body attached onto an upper surface of the magnetic planar body. The linear motor enables a speed control without an electrical current in its applied system such as an elevator, thereby excluding an additional current control system.

Abstract: An electromagnetic actuator includes an actuator rod having a plurality of magnetic assemblies disposed about a longitudinal axis of the actuator rod. Each plurality of magnetic assemblies develops alternating magnetic flux along the longitudinal axis. The electromagnetic actuator further includes a plurality of stator windings secured to a support structure and disposed about the longitudinal axis. Each stator winding has a pole facing a portion of one of the plurality of magnetic assemblies and the longitudinal axis.

Abstract: A linear drive device comprising a shaft extending in a predetermined direction and provided with a field magnet having N- and S-type magnetic poles; and a movable piece having an armature coil fitted around the shaft and opposed to the field magnet for generating a thrust when energized, being reciprocatable along the shaft, and connected to one end of a driven object, wherein thrusts generated by the armature coil at opposite sides of the shaft are determined such that the thrust generated at the side near the driven object is larger than the thrust generated at the side remote from the driven object. A linear drive device comprising a guide member; a movable piece engaged with the guide member for reciprocation along the guide member; and a sensor arranged on the movable piece for reading information on the guide member, wherein the sensor arranged on the movable piece is located substantially at a center of a yawing or pitching motion of the movable piece.

Abstract: This linear motion rolling guide unit is able to detect the relative positions and so forth of a track rail and slider by forming narrow grooves 21e in track rail 21 and arranging extremely narrow, linear scales 31 and 32 in those grooves. Thus, it is easy to reduce the size of this linear motion rolling guide unit, it is able to flexibly accommodate the particular conditions of use, and it is also inexpensive.

Abstract: A linear motor having motor magnets on a movable stage, also includes non-interleaved armature windings on a path. The magnets are arranged m along the span A of the movable stage. The armature windings are arranged with n windings occupying a distance equal to the span S. A switching device automatically switches power on to the armature windings entering the span, and switches power off to the windings leaving the span. The switching is done when the a magnet is aligned with the coil whose power is being switched on or off in order to minimizes switching noise. Switching is conveniently done using Hall effect devices controlling the switches, and a switching magnet, movable with the stage, having a length equal to the span. As the switching magnet comes within magnetic interaction distance of a Hall effect device, the Hall effect device closes its associated switch.

Abstract: A method is disclosed of temporarily speeding up delayed carriages on a return side of an endless loop of driven carriages in a linear motor web tenter.

Abstract: A linear motor employs motor permanent magnets in a movable stage interacting with armature windings in a path of the movable stage. Drive power to each individual armature winding is through a magnetically controlled switch. A switching magnet affixed to and moving with the stage actuates only those magnetically controlled switches that control power to armature windings that are within a magnetic influence of the motor permanent magnets. All other armature windings remain cut off. An encoder magnet, having alternating magnetic polarities, is affixed to and moving with the stage. The encoder magnet passes within a magnetic influence of a stationary encoder sensor which applies a stage position signal to a motor controller. The combination of motor permanent magnets, switching magnet and encoder magnet provides a wireless system that does not require active elements on the stage.

Abstract: A path module for a linear motor, for use with a linear motor stage, includes switching sensors and encoder sensors. The switching sensors energize only those armature windings that are within the magnetic influence of the linear motor stage. The stage carries an encoder magnet having magnetic zones of alternating polarity. The encoder magnet has a length D. An encoder sensor in one path module is separated from its nearest counterpart in an adjacent path module by no more than the distance D. In the preferred embodiment, each path module has three encoder sensors spaced D/2 apart, and the outer ones of the three encoder sensors are spaced D/4 from their mating ends, whereby, when adjacent path modules are assembled, closest encoder sensors in adjacent modules are spaced D/2 apart.

Abstract: The stage construction of the present invention includes a fixed stage and a magnetically levitated movable stage which is driven in mutually perpendicular X, Y, and Z axis directions with respect to the fixed stage by magnetic action between itself and the fixed stage. The fixed stage includes a magnet and a closed plenum in which the magnet is sealed. The movable stage includes a magnetic material which is opposed to the magnet and which experiences an attractive or repulsive magnetic force with respect to the magnet.

Abstract: A linear encoder system includes an encoder magnet having alternating magnetic zones. The end ones of the magnetic zones are tapered. A distance between the centers of the tapered magnetic zones defines a span. First and second encoder sensors, sensitive to the alternating magnetic zones, are spaced apart a distance equal to the span. As the encoder magnet moves into alignment with one tapered magnetic zone, and out of alignment with the other magnetic zone, the decrease in signal from one magnetic zone is approximately equal to the increase in signal from the other magnetic zone. In one embodiment of the invention, a third encoder sensor is positioned midway between the first and second encoder sensors.

Abstract: A DC machine having a primary and a secondary for generating electromagnetic movement of the secondary. The primary incorporates a plurality of parallel conductive segments arranged side-by-side along the direction of secondary movement. As the secondary moves with respect to the primary, commutating strips mounted on the secondary commutate the conductive segments of the primary according to a sequence in which successive groups of the conductive segments are interconnected to form series or parallel excitation windings. The succession of excitation windings serves to induce continuous electromotive force between the secondary. The arrangement is especially suited for a linear motor having non-returning armature windings, but may be in rotary machines as well.

Abstract: It is an object to provide a compact, lightweight, and inexpensive stage apparatus. A stage apparatus for moving a stage in a predetermined direction includes a stage accelerating/decelerating thrust generation unit arranged along the moving direction, a stage speed control thrust generation unit arranged to be parallel to the stage accelerating/decelerating thrust generation unit, an accelerating unit for generating a stage accelerating thrust at a portion corresponding to the stage accelerating interval of the accelerating/decelerating thrust generation unit, a decelerating unit for generating a stage decelerating thrust at a portion corresponding to the stage decelerating interval of the accelerating/decelerating thrust generation unit, and a speed control unit for controlling the stage thrust generated by the speed control thrust generation unit at least within a predetermined range between the accelerating interval and the decelerating interval.

Abstract: An electrical linear actuator includes a stator assembly and a piston structure. The stator assembly includes a casing having a bore extending therethrough and about a longitudinal axis, a winding structure disposed within the bore and in contact with the casing and a plurality of stator elements connected to the winding structure and arranged circumferentially in a plurality of rows extending parallel to the longitudinal axis within the bore and disposed apart from one another to form longitudinally extending channels between adjacent ones of the rows. Each of the stator elements extends radially inwardly from the winding structure toward the longitudinal axis. The piston structure includes a shaft extending along the longitudinal axis and has an outer cylindrical surface and a plurality of piston elements arranged circumferentially in a plurality of rows extending parallel to the longitudinal axis.

Abstract: A threading device for a machine for processing web-shaped material, having a guide rail extending at least sectionwise through the machine, includes a pulling device movable along the guide rail for pulling a web behind it, and an electric linear drive for activating the pulling device; and a method of threading the web through the processing machine.

Abstract: The present invention comprises an improvement of a known bi-directional linear motor and is applicable to other linear motors. The linear motor comprises a plurality of pole pieces arranged as a closed frame having three horizontal pole pieces and two vertical end pieces with permanent magnets mounted therein to form a closed stator core having a symmetrical permanent magnetic flux field path in the stator. A force coil is mounted over the center pole piece of the three horizontal pole pieces. When force current is applied to the force coil a reaction flux is generated in the stator core which creates an unbalanced flux field in the stator core. At least one air gap is provided in at least one of the pole pieces through which the reaction flux passes to increase the magnetic inductance which in turn increase the force on the force coil for a given force current.

Abstract: The invention is directed to a linear motor and a image reading apparatus. The motor comprises a rod-like stator formed of a magnetizable rod-like member provided by magnetization with a drive field magnet and a plurality of magnet portions providing multiple kinds of position information; a movable piece being movable along said stator and having an armature coil opposed to said field magnet; and a sensor reading the position information from the plurality of magnet portions. The apparatus includes motors such as the foregoing linear motors as drive source for sliders to be driven for scanning a document image.

Abstract: An XY drive apparatus is described that is thin and enables the performing of both high-precision and high-speed work. The above advantages are achieved by using flat linear electromagnetic actuators for the driving source that perform high-speed work. In addition, these linear electromagnetic actuators are arranged on both sides of the apparatus, thereby preventing deviations in operation between both sides to achieve highly accurate positioning.

Abstract: An apparatus is disclosed which detects the residual quantity of bobbin thread on a sewing machine bobbin when the shuttle containing the bobbin is located at a specific phase position. The apparatus includes a detection rod driven by a solenoid so that one end contacts the outer periphery of the residual bobbin thread. A sensor signals when the amount of residual thread is less than a predetermined quantity.

Abstract: A linear actuating apparatus includes a shaft moved by a linear actuator means to slide along a center axis. A vertical position detector are provide for detecting the current position of the shaft to produce position signals indicative of detected positions. An actuation controller controls the movement of the shaft based on the position signals from the position detector.

Abstract: An Electromagnetic Levitation Catapult for preliminary acceleration of a heavy individual payload includes a Magnetodynamic Levitation and Stabilizing Self-Regulating System providing stable flight of the payload along a pre-determined trajectory, a rotor with changeable size of the pole pitch, a stator extended along the trajectory of flight and a synchronizing mechanism. The stator is divided into three distinct sections: a start section where the winding turns have the same length, an acceleration section where the length of the turns increases in the direction from the start section, and a deceleration section. The payload is supported by a chassis carrying the rotor, so that when the rotor engages the stator, a propulsion force is created and propulses the payload along the trajectory. The rotor includes immovable long magnets and short magnets capable of being moved in the vertical direction. The synchronizing mechanism co-ordinates the pole pitch of the rotor with the turn length of the stator winding.

Abstract: An X-Y positioning machine has a forcer, with armature coils, that moves around on a platen, supported by an air bearing. Magnets embedded in the motor platen generate a fixed magnetic field with which the armature coils interact. Perpendicular elongated coils interact with the fields of magnets in columns and rows. When a traditional rectangular pattern of the magnets is provided, a packing density and average peak magnetic flux intercepted by the coils are limited to 50%. The present invention provides magnet configurations that provide greater than 50% maximum peak flux density and up to 100% packing density. Several magnet arrangements are provided: a first in which round magnets are used instead of square, and a second in which diamond-shaped magnets are used. The latter can be used at 100% packing density arrangement. In addition to high peak flux density for a narrow coil, these embodiments exhibit low cogging forces. A method of making the magnet is also provided.

Abstract: A dual guide beam stage mechanism for accurate X-Y positioning for use e.g. in semiconductor processing equipment provides accurate planar motion and yaw control. Over-constraint between components in their relative motion is minimized by utilizing flexibly mounted air bearings at the connection between at least one of the moveable guide beams and its corresponding stationary guide, and between at least one of the guide beams and the adjacent stage itself. Thus stage yaw motion is provided by allowing yaw motion of one of the guide beams. Preloading provides enough constraint through the air bearings without over-constraining the moving components, thereby improving accuracy and also reducing the need for close manufacturing tolerances.

Abstract: A target state quantity generating unit generates a target state quantity for a stage, and a laser interferometer detects the current state quantity (position) of the stage. Based on the target state quantity and the detected state quantity (position), a compensation system constituted by a variable phase compensator and a PID compensator controls the driving operation of the stage. A memory unit stores forward and reverse gain tables, and provides adjustment information for adjusting the compensation system in correspondence with the state quantity of the stage. The corresponding gain table is selected on the basis of the driving direction of the stage, and the adjustment information is read out from the selected gain table on the basis of the position of the stage. The corner frequency of the variable phase compensator is changed on the basis of the readout adjustment information.

Abstract: A linear motor apparatus includes a stator extending in a predetermined direction and having a field magnet for driving; a movable piece having an armature coil opposed to the field magnet, and being reciprocatable along the stator; a Hall element disposed at a portion on the movable piece opposed to the field magnet for outputting a voltage signal depending on an intensity and a direction of a magnetic field formed by the field magnet as well as a Hall element reference input voltage supplied thereto; a correction circuit for producing an output signal by correcting an output signal issued from the Hall element to have a cycle equal to that of the Hall element output signal and a constant maximum amplitude depending on the Hall element reference input voltage; and a current supply circuit for supplying a current, depending on the output voltage issued from the correction circuit, to the armature coil for producing a driving force of the movable piece.

Abstract: A linear motor drive system which is substantially not influenced by deviations in shape of slits, uneveness of distribution of light, and high order high harmonic components of a sensor signal, and which comprises a linear optical encoder having high sensor accuracy and which enhances the position detecting resolution of the encoder without use of high frequency clock generator.The system comprises means for detecting the movement of the slider of the linear pulse motor by use of a linear optical encoder and means for feedback control of the motor based on the sensor signal, wherein a photodiode array is extended over a plurality of rows of slits on a scale plate; a diffuser is mounted between a light source and the scale plate, and n photodiodes are provided within one pitch of the slit, the width of one photodiode in the direction of the array is set at p.sub.0 /(n+1), and the width of a gap between the photodiodes is set at p.sub.0 .multidot.n(n+1).

Abstract: There is provided a position control drive system having first and second drive units linked together and travelling on parallel running rails. A passive unit riding on a third parallel running rail is pivotally linked to one of the drive units. The pivoting link allows movement of the drive units longitudinally along the rails, but prevents movement in other directions. The pivot compensates for positional differences between the electronic positional control of the drive units and the mechanical linkage preventing the inefficiency in the electronic system, stresses in the mechanical system and, in severe cases, binding of the drive units to the rails.

Abstract: Position apparatus for controlling the movement of a table, on which a semiconductor work is carried along a unidirectional path in rectangular coordinate system. The table is driven in a single plane by x and y coordinate drive control means. The position apparatus includes guide means for supporting the table on the base; first drive means for driving the table in a first direction, a second drive means for driving the table in a second direction opposite to the first direction and controller means for controlling the first and second drive means to cause the table to stop without causing table vibration and without overshoot.

Abstract: A linear magnetic actuator has a pair of stator windings (14, 15) of opposite polarity formed inside a cylindrical soft iron shell (16) providing a slotless back iron piece. The axially movable shuffle comprises a soft iron shaft (11) with a pair of radially magnetised annular permanent magnets (12 and 13). The arrangement has cylindrical symmetry and the stator windings are as thin as possible to minimise the air gap between the cylindrical pole faces of the annular magnets and the back iron.

Abstract: A Linear Synchronous Motor for a high-speed, ground transportation vehicle includes a linear extended guideway stator assembly containing two extended symmetrical three-phase stator windings supported on the guideway and a rotor installed on the vehicle chassis and having an even number of identical units. When the winding is powered by three-phase sinusoidal current of constant frequency, the traveling wave of the sinusoidal current arises and runs along the stator. By varying the length of the turns of the stator windings, the velocity of the traveling wave is variable on different sections of the guideway, which include acceleration section, constant velocity section and deceleration section. Each of the rotor units includes vertically magnetized permanent magnets and two "C"-shaped steel cores which close the magnetic lines through two parallel air gaps. The permanent magnets move downward and upward within the "C"-shaped steel cores.

Abstract: A system and method for supplying power to stator sections of a long-stator magnetic levitation railway system, where the stator winding is subdivided into several stator sections that can be controlled individually along a route for a magnetically levitated vehicle, where the stator sections can be connected to at least one feeder cable system running along the stator sections via at least one section switch, and at least one converter is provided for each feeder cable system, where one or more converters are provided in at least one substation along the stator sections, and each converter creates a voltage supply system for the stator sections, where the operating voltage in the feeder cable systems is not the same as the operating voltage of the stator sections, and at least one matching transformer is connected between the feeder cable systems and the stator sections so the operating voltage of the feeder cable systems can be transformed to the operating voltage of the stator sections.

Abstract: A weight supporting apparatus supports the weight of a structure required to have very high surface precision, without affecting the surface precision of the structure. The weight support apparatus includes a driving unit for moving a driven body in the direction of gravity with respect to a base, and a supporting unit for supporting the weight of the driven body at a position after being driven, wherein the driving unit and supporting unit are so arranged that the drive force of the driving unit and the support force of the supporting unit are on the same axis.

Abstract: The linear direct current motor is described that is able to maintain stable thrust at all times regardless of changes in the relative positions of the primary and secondary sides.The endmost magnetic poles of a field magnet are used as non-detected magnetic poles with respect to magnetic pole discrimination elements, while these non-detected magnetic poles are used only as driving magnets for generation of thrust, thereby reducing the range of variation in the number of conductors of armature coils that actually generate thrust. In addition, since the drive current supplied to the armature coils is in the form of a constant current, changes in thrust can be further reduced.

Abstract: A core made of a soft magnetic material is supported to be movable, and a permanent magnet is mounted to move with the core. At least one electrically conductive drive coil is located adjacent the core and one pole of the permanent magnet. A casing, made of a soft magnetic material, is located adjacent to the drive. An electrically conductive sense coil is located adjacent one end of the core, such that when electrical current is passed through the drive coil in a first direction, the core is moved in a first direction and an electrical property associated with the sense coil is altered, thereby indicating the position of the core, and when electrical current is passed through the drive coil in a second direction, the core is moved in a second direction and an electrical property associated with the sense coil is altered, thereby indicating the position of the core.

Abstract: A rocking motor comprises a coil wound around a hollow coil bobbin. A rotor is rotatably mounted at a position close to an end portion of the coil bobbin. The rotor has a center shaft and a permanent magnet and is magnetized with two poles such that the positions of the poles are located close to the coil and the magnetization angle is greater than 90 degrees but less than 180 degrees. The positions of the poles of the rotor and the coil are adjacent to one another so that a rotary torque can be efficiently obtained by a magnetic force generated by the coil. The rocking motor can generate a high power output with a relatively low power supply and its operational performance is not adversely affected by an external magnetic field.

Abstract: In one embodiment described in the specification, a surgically implantable reciprocating pump employs a check valve as the piston, which is driven by a permanent magnet linear electric motor to assist either side of the natural heart. The pump is implanted in the aorta or pulmonary artery using vascular attachment cuffs such as flexible cuffs for suturing at each end with the pump output directly in line with the artery. The pump is powered by surgically implanted rechargeable batteries. In another embodiment, pairs of pumps are provided to replace or assist the natural heart or to provide temporary blood flow throughout the body, for example, during operations to correct problems with the natural heart.

Abstract: An electromagnetic actuator includes an actuator rod having a plurality of magnetic assemblies disposed about a longitudinal axis of the actuator rod. Each plurality of magnetic assemblies develops alternating magnetic flux along the longitudinal axis. The electromagnetic actuator further includes a plurality of stator windings secured to a support structure and disposed about the longitudinal axis. Each stator winding has a pole facing a portion of one of the plurality of magnetic assemblies and the longitudinal axis.

Abstract: A moving coil linear actuator including an elongated permanent magnet having a cross-sectional width substantially greater than its edge height and having an elongated length of soft magnetic material disposed along one or both edges of the permanent magnet to enhance the magnetic field strength in the gap through which the moving coil translates.