Abstract: An objective lens driving device used in an optical recording and/or reproduction apparatus comprises a lens holder, elastic supporting members, a coil bobbin and a yoke. An objective lens is mounted in the lens holder. The elastic supporting members have one end attached to the lens holder and the other end attached to a mounting part. The elastic supporting members support the lens holder movably in a direction parallel to the optical axis of the objective lens and in a plane perpendicular to the optical axis. A coil for focusing and coils for tracking are wound on the coil bobbin. A magnet is mounted on the yoke, and the width of this magnet is selected so that flux from the magnet acts only on effective portions of the coils for tracking.

Abstract: A linear motor of the type used to control the radial position of a write/read transducer relative to a rotating data storage disk comprises an elongated tubular-shaped permanent magnet which concentrically surrounds and is spaced, by an air gap, from an elongated pole piece of highly permeable material (e.g. steel). A selectively energizable coil, concentrically arranged between the magnet and pole piece, is adapted to move axially in response to an applied current. According to the invention, the pole piece supports a plurality of "shorting rings" made of high conductivity, low permeability material. The shorting rings are embedded in the pole piece so as to be coextensive with the surface thereof. The spaced shorting rings function as a "shorted turn" which operates to reduce the rise time of current applied to the coil without significantly reducing the magnetic flux in the air gap through which the coil is linearly driven.

Abstract: An internal combustion unit having a cylinder with at least one power piston with thermal means for reciprocating the power piston in the cylinder, the power piston and cylinder defining a combustion chamber, and a generator unit having a linear inductor piston coupled to the power piston for reciprocation together with the power piston and a stationary coil stator constructed in the configuration of an annulus, wherein the inductor piston reciprocates in the annulus of the coil stator and electrical current is generated in the stator.

Abstract: A linear motor having a magnetic circuit and a moving coil, the magnetic circuit comprising a linear yoke provided at the center of the circuit and a pair of linear magnets, the linear yoke and the pair of linear magnets forming a pair of linear gaps with the linear yoke interposed therebetween, the magnetic circuit applying a magnetic field to the linear gaps, the movable coil mounted on the linear yoke of the magnetic circuit being moved along the linear yoke by an electromagnetic action to the magnetic circuit when the movable coil is powered, wherein the linear magnet has a larger magnetic force at opposite end portions in the longitudinal direction of the linear magnet than at an intermediate area, the magnetic reluctance of the magnetic circuit is made large to obtain a driving current of the movable coil corresponding to the magnetic reluctance when the moving coil moves at the intermediate area of the linear magnet, or the magnetic circuit is mounted on a plate made of material having the same magneti

Abstract: A precision linear actuator (10, 120, 140) is provided particularly adapted for accurately controlling the positioning of a lens element in the optical system of a guided vehicle such as a missile. The actuator includes a frame (12, 130, 142) rigidly affixed to the missile structure which includes a pair of bearing supports (30, 32) and a pair of separated guide pockets (24, 26). A lever (14, 122, 150) is installed within the frame (12, 130, 142) and is fixed to the frame by bearings (44, 46) which enable the lever to undergo slight rotation with respect to the frame. An actuator mechanism in the form of a voice coil (56), drive motor or other device is employed to drive the lever (14, 122, 150) to undergo its rotational motion. A lens holder (16) is installed within an open area inside the lever (14, 122, 150) and defines separated guide rails (76, 78, 80, 82) which enable it to be moved linearly with respect to the frame (12, 130, 142).

Abstract: A voice coil motor is disclosed which comprises a yoke member composed of a central portion forming magnetic path, left/right fringes and upper/lower fringes, a moving coil wound movably around the central portion of the yoke member, and permanent magnets being adhered on the upper/lower fringes of the yoke member and applying magnetic field to the moving coil, wherein the yoke member is formed by overlapping at least two members of different permeabilities so as to uniform each reluctance of lines of magnetic force being generated from the permanent magnets and flowing through the yoke member.

Abstract: An improved device for generating an alternating electrical current is disclosed, employing a stationary electrical exciter coil and inductive ouptut coil, and a pair of reciprocating elements to selectively alternate between a plurality of magnetic flux field paths. The reciprocating elements each have relatively staggered magnetically permeable portions for alternatingly establishing one of the magnetic flux field paths. The alternating flux field paths, each passing through the center axis of the inductive output coil, cause the reversal of the direction of magnetic flux flow through the center axis, inducing the inductive coil to generate an alternating output current.

Abstract: The moving coil actuator of a pressure regulator has two threaded adjustment screws each mounted parallel to the actuator's path and which project through a limit surface of a carrier for the moving oil actuator. Both adjusting screws can be rotated by means of a tool, but their mounting prevents them from being moved longitudinally. Each of the adjustment screws carries a limit element, one on each side of the carrier's limit surface. The position of each of the limit elements on its adjustment screw is adjustable by means of an internal thread. In the preferred embodiment, each adjustment screw is partly enveloped by a projection on the limit element carried by the other adjustment screw, by which each limit element is secured against rotation during adjustment. The limit elements independently limit the stroke of the moving coil at each end by blocking movement of the limit surface when the actuator reaches its desired limit.

Abstract: A linear alternator/motor which is capable of translating the energy of linear mechanical motion into electrical energy, and/or also transforming electrical energy into linear mechanical motion. There is an inner pole member and an outer circumferential pole member defining first and second annular gaps. An armature component comprising first and second coil sections, positioned in the gaps, reciprocates relative to the the pole members. The coil sections have current flowing therein so that field portions of these coils coupled into the main magnetic field substantially cancel each other as the coil selections move between end positions.

Abstract: The apparatus includes a driver (86). The driver (86) includes a front portion (90) which is adapted to receive a riveting die (92), and a rear portion (88) which is a copper plate. The copper plate (88) is receptive to the establishment of magnetic field currents therein. The actuator further includes a coil (72) which is positionable in close proximity to the copper plate (88) of the driver (86). The apparatus further includes a bank of capacitors having a stored charge so as to produce a current pulse through the coil (72) when the capacitors are connected to the coil (72). Still further, the apparatus includes a control means for selectively connecting the stored charge from the capacitors to the coil. The copper plate (88) is relatively thick compared to that used in high voltage electromagnetic actuators, such that the present apparatus requires only a relatively low voltage in order to produce the required high forces to accomplish the desired riveting.

Abstract: An actuator has a stepping motion function with a high stopping accuracy and resolution. The actuator includes a fixed portion and a movable portion constructed in combination so as to be movable relative to each other, a coil for imparting a moving force to the movable portion, a magnetic recording medium mounted on one of the fixed portion and the movable portion and recording magnetic signals, and a plurality of magnetic sensors mounted on the other thereof for detecting said magnetic signals in said magnetic recording medium, and wherein signals different in phase and output from said respective sensors are used by themselves, or signals inversely converted from the former signals are additionally used, and the coil is supplied with a driving force command by sequentially selecting and changing those signals.

Abstract: An electromechanical linear motor incorporating a number of electrically conductive drive coils arranged axially and embedded in a composite matrix so as to form a hollow cylinder within which a piston or pistons are placed. Permanent magnets or conductive coils arranged around the circumference of the pistons interact through magnetic coupling with the drive coils so as to cause the piston to move in accordance with the currents applied to the drive coils. These currents are supplied through logic control circuitry which receives inputs from a number of sensors including piston position sensors, thermostats, pressure transducers and timers. Based on the information received from these sensors, a microprocessor controlled power circuit provides electrical pulses of a frequency, amplitude and duration designed to produce piston motion appropriate to the specific application.

Abstract: A rotary actuator includes a case, a shaft rotatably supported in the case, a moving coil with conductors extending radially from the shaft as a center, a support which supports the moving coil on the shaft, facing magnets set with facing unlike poles arranged alternately in the direction of motion of the moving coil on either side of it and generating a magnetic flux which crosses the moving coil conductors, a device for restricting rotation of the shaft such that the conductors of the moving coil do not move outside the magnetic flux generated by the magnet set, and a drive unit for sending electric current through the moving coil. The rotary actuator may further include an assisting device for assisting shaft rotation which includes moving magnets on the side edges of the support and fixed magnets installed in the case facing the moving magnets, either the moving or fixed magnets being electromagnets.

Abstract: A method for repositioning garter springs around the pressure tubes of Candu-type nuclear reactors. A primary coil having a high permeability core is inserted into the pressure tube. The coil is energized by an alternating current of a frequency and amplitude sufficient to produce a primary alternating electromagnetic field that penetrates the wall and induces an eddy current in the garter spring. A secondary alternating electromagnetic field is also produced and is reactive with the primary field to produce a travelling electromagnetic field of sufficient intensity and of such direction that the resultant of the electromagnetic forces acting on the garter spring causes the spring to move along the tube.

Abstract: The apparatus includes a driver (86). The driver (86) includes a front portion (90) which is adapted to receive a riveting die (92), and a rear portion (88) which is a copper plate. The copper plate (88) is receptive to the establishment of magnetic field currents therein. The actuator further includes a coil (72) which is positionable in close proximity to the copper plate (88) of the drive (86). The apparatus further includes a bank of capacitors having a stored charge so as to produce a current pulse through the coil (72) when the capacitors are connected to the coil (72). Still further, the apparatus includes a control means for selectively connecting the stored charge from the capacitors to the coil. The copper plate (88) is relatively thick compared to that used in high voltage electromagnetic actuators, such that the present apparatus requires only a relatively low voltage in order to produce the required high forces to accomplish the desired riveting.

Abstract: An improved voice coil actuator for a head arm assembly. The portions of the voice coil which do not pass between the permanent magnets, and thus form a return path for the current, are bent substantially perpendicular to the remainder of the coil. One of these perpendicular portions is fixed to the head arm assembly by bonding or otherwise. The perpendicular arrangement of the return portion of the coil does not effect the coil's performance because this portion does not pass between the permanent magnets and thus is not involved in generating the force which moves the head arm assembly. Such an arrangement causes the voice coil to take up less room, allowing it to be placed closer the edge of the disk drive housing.

Abstract: Solenoid actuators comprising an armature mounted along its planar edge by ball bearing elements within a stator frame assembly. The armature and stator frame include opposing grooves at the plane of the armature in which the ball bearing elements are captured. The stator comprises multiple pole pieces having conductive ribbon stock wound therearound for connection to a source of electrical power to move the armature on the ball bearing elements within the frame. Fixed axis, variable position linear actuators, variable axis linear actuators and rotary actuators are disclosed as preferred embodiments. Modified embodiments include a stator assembly wherein opposed stator poles are staggered laterally of the actuator centerline so as to be positioned between adjacent pairs of opposed poles. The armature may be flat or may comprise a juxtaposed spaced pair of armature plates which have internested undulations which project between adjacent pairs of the opposing stator poles.

Abstract: A linear actuator assembly for linearly the reciprocatingly moving magnetic heads in a magnetic disk storage apparatus. This linear actuator has a carriage for supporting magnetic heads, and a voice coil for moving the carriage. The sectional configurations of the carriage and the voice coil are equalized, thereby enabling the transmission of the driving force from the voice coil to the carriage without any eccentricity. This linear actuator also has a vibration absorbing mechanism for absorbing vibrations caused when the linear actuator operates, and a runaway prevention mechanism for limiting the movable range of the carriage.

Abstract: An electromagnetic linear motor having a variable length stroke and providing a substantially large force in both its power stroke and return stroke includes concentric inner and outer magnetic circuits arranged coaxially for movement relative to one another in a rectilinear path with reciprocating motion in response to the interaction of magnetic fields produced by the inner and outer magnetic circuits, respectively. The length of the stroke and the rate of reciprocation are directly proportional to the magnitude of the voltage used to excite primary and secondary coils which generate the respective magnetic fields and the rate at which the polarity of the voltage applied to the secondary coil is changed between negative and positive polarities.

Abstract: A nonlinear control system adapted to drive and control the speed, stroke, phase and center position of a reciprocating linear motor by means of phase locked loop techniques and the electromechanical filtering properties of linear motors. The control system comprises a tri-state switching amplifier in conjunction with 3 distinct feedback control loops to accurately determine the amplitude, center position and phase of the motor. The first feedback control loop includes a low pass averaging circuit and compares the motor position with a reference signal to achieve the desired motor position. The second feedback control loop includes a peak detector and determines the stroke of the reciprocating motor. The third feedback control loop operates as a phase locked loop to control the phase of the motor. The control system provides high efficiency, high reliability and low cost.

Abstract: A transducer in the form of a long cable for producing electrical signals in response to mechanical vibration of the cable. The cable comprises an elongate magnetic member and an electrical conductor extending alongside the magnetic member, the electrical conductor being loosely mounted in the magnetic field of the magnetic member so that mechanical vibration of the cable causes the electrical conductor to move relative to the magnetic field whereby an e.m.f. and hence an electrical signal is induced in the conductor. The transducer may be used in monitoring or security apparatus.

Abstract: A linear motor of moving-coil type is disclosed, in which a multi-phase moving coil includes a plurality of flat coil units each not wider than the longitudinal length of a permanent magnet making up a stationary part divided by the number of coil phases, the flat coil units being arranged successively in the same plane with central parts not adjacently overlaid one on the other. The central parts of the moving flat coil units have a thickness equivalent to a single phase in spite of the multiple phases of the moving coil. Thus a great electromagnetic force is generated, and at the same time a high propulsive force is obtained with the magnetic flux density not reduced in the gap accomodating one phase of coils alone.

Abstract: A non-linear electromagnetic vibration device including a first vibration part and a second vibration part. A non-linear bellows plate spring set is connected between the first and second vibrating parts. Each spring set is composed of sequentially coupled bellows plate springs, and each plate spring is elastic according to a predetermined particular waveform and has a plate structure of a predetermined shape. The waveform is selectable among many including portions of an exponential curve. The plate structure of each spring is rectangular with an edge which is straight, convex, or concave in contour. The first vibration part of the device is rigidly connected to a corresponding section of each spring set and the second vibration part of the device is coupled to a different or second area of each spring set.

Abstract: This invention provides a structure for damping longitudinal vibrations in an apparatus which moves longitudinally.It employs, in a longitudinally moveable body, a structural element, slotted in the longitudinal direction, so that said structural element has relatively rigid upper and lower portions and relatively flexible flextures at the slot ends. A layer of elastomeric material covers a side of said element and a stiffening plate covers said elastomeric layer.

Abstract: A controlled electric drive (CED) device comprises a pair of rectangular magnetic poles of different polarity arranged adjacent, parallel, and congruent to each other with a relatively narrow gap therebetween, providing an essentially uniform magnetic field between the pole faces. The device further comprises a driver conductor arranged to move freely between the magnetic pole faces in such a manner that an electric current running through the driver conductor will tend to move the conductor out of the magnetic field at right angles to the conductor and to the direction of the magnetic lines of force defining the magnetic field. The device further comprises a controller conductor wound in a flat, essentially rectangular spiral fixed adjacent to, and insulated from, the driver conductor. The controller conductor is so arranged that its longitudinal direction is parallel to the driver conductor, and has first and second portions, with direct current flowing in opposite directions in each of the portions.

Abstract: A nonlinear control system adapted to drive and control the speed, stroke, phase and center position of a reciprocating linear motor by means of phase locked loop techniques and the electromechanical filtering properties of linear motors. The control system comprises a tri-state switching amplifier in conjunction with 3 distinct feedback control loops to accurately determine the amplitude, center position and phase of the motor. The first feedback control loop includes a low pass averaging circuit and compares the motor position with a reference signal to achieve the desired motor position. The second feedback control loop includes a peak detector and determines the stroke of the reciprocating motor. The third feedback control loop operates as a phase locked loop to control the phase of the motor. The control system provides high efficiency, high reliability and low cost.

Abstract: The invention relates to a method for controlling a closed loop linear position servo-motor having an armature including a first group of excitation windings and a second group of excitation windings, and a stator including field magnets disposed radially opposite the first winding group, and feedback windings disposed radially opposite the second winding group.

Abstract: A winding method for winding the coils of a stator structure which has one or more intermediate coils and a pair of end coils having a reduced number of turns. The coil or coils may be directly connected to supply terminals and the coils are connected in series. The method involves using a dummy connector to form a connection point between the two end coils, all the coils being wound from a single length of wire with the dummy connector forming the start and finish point for the winding operation.

Abstract: A construction for actuator assemblies is disclosed using a material of low permeance as a structural element, included normal to the axis of coil movement to lower coil inductance by reducing reactance flux in support structures and providing a channel for eddy currents set up in response to coil reactance. The net result is enhanced coil responsiveness to energization.

Abstract: An armature structure for an electrodynamic shaker comprises an armature support and an armature coil assembly mounted on the support. The coil assembly includes a cladding, or alternatively a spine, of a carbon fibre material. Preferably the carbon fibres extend generally longitudinally of the armature, that is to say in its direction of motion.

Abstract: A moving coil type linear motor comprises a rail of generally U-shaped cross section, permanent magnets of flat plate-shape and magnetized in the direction of thickness and provided on an inner side of the rails with varied polarities of magnetic poles next to each other. A pair of coils whose length is 1.5 times that of the magnetic pole and has a space of 0.5 times the length of the magnetic pole in the center thereof, are disposed opposingly with the permanent magnets and travel along the permanent magnets within the rail. Brushes are provided with the respective coils, and a feeder pattern arranged on an inner side of the rail, feeds electric power to the coils through the brushes, only when respective active coil parts of the coils are fully in the magnetic flux of the same direction. The linear motor also comprises sensing means for detecting signals regarding the traveling of the coils, and controlling means for controlling the travel of the coils on the ground of the signals from the sensing means.

Abstract: A vibrating compressor comprising an external iron core, a permanent magnet, an internal iron core, and an electrocmagnetic coil vibratably supported by a mechanical vibrating system in a magnetic gap between the two iron cores to drive a piston connected thereto; the permanent magnet being composed of a high residual (remanence) magnetic flux density magnet, as represented by an alnico magnet, and a high coercive force magnet, as represented by ferrite magnet, and disposed separately.

Abstract: A linear motor having improved magnetic characteristics in driving a coil and in preventing flux leakage which is particularly useful with a magnetic disc memory. The motor includes a magnetic housing having top and bottom surfaces, side surfaces and one end surface with the end surface including integral first and second magnetic center pieces. An end plate mates with the magnetic housing with the end plate having integral first and second magnetic center pieces which mate with the first and second magnetic center pieces of the housing. First, second, and third magnets are mounted to the top and bottom surfaces and one side surface of the magnetic housing in cooperative relationship with the first center piece. Fourth, fifth, and sixth magnets are mounted to the top and bottom surfaces and the other side surface of the housing in cooperative relationship with the second magnetic center piece. A coil is coupled to the first and second magnetic center pieces and drives a carriage assembly.

Abstract: A linear motor of the type having an elongated stator contained in a U-shaped channel includes a linearly moving element connected to its load by a connecting beam which passes out of the U-shaped channel. A flexible seal on each arm of the U-shaped channel seals against the sides of the beam where it passes out of the U-shaped channel and opposed elements of the seal abut each other to provide a barrier in other areas. In one embodiment of the invention, a positive pressure of a clean gas is maintained within the sealed U-shaped channel to prevent entry of atmospheric contaminants. In another embodiment of the invention, the seal in the vicinity of the beam is purposely made less than perfect so that the cooling gas is encouraged to flow toward, and exit in the vicinity of, the region where maximum cooling is required.

Abstract: A reversible vibratory motor includes a driving member responsive to a first frequency of vibration for driving a driven member in a first direction, and responsive to a second frequency of vibration for driving the driven member in the opposite direction.

Abstract: A linear motor for the high-speed reciprocating movement of a mass-possessing rotor slide component and particularly of a radiation filter, with parallel flat stator plates with permanent magnets which are fitted to the facing sides of the stator plates and set up a magnetic field across the air gap between them. Fitted to the slide is a coil which can be slid in the permanent magnetic field. The coil consists of an aluminium foil provided at its surface with an insulating layer, which foil is wound to form an air-cored coil, and the slide is supported on gas bearings which extend through the aluminium bridges between the stator plates. To avoid impacts during acceleration and braking linear motors working reciprocally are provided.

Abstract: There is disclosed a closed-loop, linear position servomotor. The servomotor includes a tubular armature disposed within a tubular stator in which the stator includes, radially disposed throughout the shell thereof, a plurality of magnetically symmetric field magnets, each having its magnetic axis directed to the radial center of the stator and armature. The stator further includes a plurality of symmetric, longitudinally disposed alternating current excitation windings, the longitudinal extent of such windings corresponding to the extent of change in linear position of the servomotor. The armature of the servomotor has a non-magnetic substrate upon which is longitudinally wound high current, direct current windings, these windings comprising the primary windings of the servomotor, with the excitation windings of the stator comprising the secondary windings of the motor.

Abstract: A stator comprising a cylindrical permanent magnet and a helical charging coil wound thereon and embedded inside a cylindrical plastic casing, and a reciprocator comprising two cylindrical electromagnets with helical charging coils wound thereon and a helical charging coil embedded inside a hollow cylindrical plastic casing enclosing the stator. The two electromagnets are mounted at opposite ends of the permanent magnet and are axially aligned therewith, with an intervening space to allow for longitudinal movement of the electromagnets. The helical charging coil occupies the electromagnetic field of the permanent magnet.The helical charging coils of the electromagnets are wound in opposite directions so that when one electromagnet attracts one end of the permanent magnet, the other electromagnet repels the opposite end.

Abstract: An arrangement for a linear motor which uses a shorted turn as a shield for the magnet of the motor to thus provide a substantial reduction in the introduction of particulate matter into the Head Disk Assembly environment associated with the linear motor, without substantially increasing the reluctance of the magnetic circuit of the motor.

Abstract: A coil for a voice coil actuator employed in a transducer positioning system of a disk file is disclosed in which the coil is constructed to minimize vibrations in a direction parallel to the coil axis which tend to occur as a result of rapidly energizing the coil during the seek and track following modes of the positioning system. The coil is characterized by a composite layer of viscoelastic material and aluminum foil disposed between the coil bobbin and the coil winding where the aluminum foil functions to increase the shear deformation of the viscoelastic material and its modulus of rigidity.

Abstract: A two axis linear motor for carrying the objective lens for optical focusing and optical tracking in an optical recording system has a stationary structure for providing a magnetic field and a moving armature structure. The stationary structure may have two permanent magnets and several pole pieces to properly shape the field with respect to the armature. In one embodiment, a central elongated pole piece and two parallel adjacent elongated pole pieces which are associated with two permanent magnets to form flux gaps with the central pole piece. Flux returns to the magnets through a lower pole piece to which the central pole piece is attached. The central and lower pole pieces have an aperture through which the laser beam may pass on its way to and from the objective lens.

Abstract: An electromagnetic device includes a stator structure defining spaced circumferential grooves in which are wound windings. Pole pieces are disposed between adjacent grooves and each pole piece has an axial slot in its periphery and a tangential slot formed in one side face, the tangential slot extending from the axial slot to adjacent the base wall of the groove. The slots accommodate the interconnection between the windings in adjacent grooves.

Abstract: A pump includes a pair of circular metal bellows rigidly secured to the pump housing at the perimeter of their accordion-like ring structures and interconnected at their centers so as to be capable of flexing in phase. An electrical coil is attached to the interconnected bellows and is axially movable with the bellows. The coil is surrounded by a permanent magnet structure secured to the pump housing. Each bellows communicates with an associated fluid chamber which has a valve structure for the inlet and outlet of fluid. The coil is electrically connected to an alternating current power supply, the connection being made through the electrically conductive bellows. The bellows flex in phase in the presence of the alternating current to the coil and thus alternately pull fluid in and force fluid out of the respective fluid chambers. Since the fluid chambers are connected to a common fluid output and since the bellows axially flex in phase, there are two pressure pulses per pump cycle.

Abstract: A magnetic drive unit includes a magnetic circuit composed of a yoke and a magnet which define a magnetic gap therebetween, and a voice coil movably disposed in the magnetic gap for moving a driven member, the voice coil comprising turns formed by helically cutting a tubular conductive body, the turns being spaced at pitches which are larger within the magnetic gap and become progressively smaller in directions away from the magnetic gap. The turns are of a rectangular cross section and insulated by a mass of resin coated on their surfaces.

Abstract: A linear motor comprising a moveable coil, a stationary core in which the coil moves, and a drive member including a shaft and a bearing, the shaft moveable in the bearing and passing through the core. In the preferred embodiment, the drive member includes a pair of circular plates connected by three shafts that slide in bearings passing through the motor core, with the coil attached to the periphery of one of the plates. Springs having varying coil spacing are seated between the plates and the motor core to damp the motor's motion, with the strongest damping at the ends of its reciprocating stroke.

Abstract: A linear motor (10) for use with a read/write head of computer disk storage or the like includes a rectangular housing (12) having a central bore (14) extending axially therethrough. A cantilevered pole piece (16) extends concentrically through the bore (14). Elongated and radially polarized bar magnets (20) are secured to the housing (12) on the bore surface or to the pole piece (16) and positioned so that radial axes extending diagonally from the center of the bore (14) to each of the housing corners (22) biscet the magnets (20). An armature (25) having a coil wire (30) is concentrically positioned within the central bore (14) between the pole piece (16) and the magnets (20) (or between the magnets (20) and the housing (12)). Forces are exerted on the coil wire (30) in response to application of electric current through the coil wire (30) in the presence of magnetic flux produced by the magnets (20).

Abstract: A linear stroke reciprocating electric machine provides both high efficiency and linearity. A cylindrical air gap is defined between outer and inner gap defining surfaces, at least one of which has a length equal to the length of an electric coil plus the length of the stroke. A flux focusing ring, having a length in the direction of movement equal to the length of the coil in the same direction, concentrates substantially all the field flux and all of the electric coil turns to interact over the entire stroke.

Abstract: A generator for generating seismic pulses comprises an armature and a sta coaxially arranged relative one another. The magnet cores of both the stator and the armature have on their active surfaces alternately disposed annular projections and annular slots. The winding sections are laid into and flush with said slots. The windings of the armature and of the stator are arranged to face one another. The generator is provided with means for fixing it in a vertical and a horizontal planes. In case the armature is made two times shorter than the stator the sections of the winding of said armature are arranged in groups. The number of the sections in each group of the stator equals the number of the sections of the armature. Such arrangement of the component parts enables the armature to reciprocate and to thereby provide formation of lateral seismic waves.

Abstract: An electromagnetic apparatus comprises a magnetic assembly having an annular air gap, a wire coil, and an arrangement for energizing the coil only in the air gap, the magnetic assembly being disposed coaxially of the coil so that the coil is movable in the air gap relative to the magnetic assembly. The preferred coil is formed of a plurality of narrow segments axially adjacent and electrically connected in series, successive segments abutting one another, each segment being spirally wound from radially overlapping and abutting turns of wire, the abutting segments being alternately wound inwardly and outwardly such that adjacent sections spiral radially in opposite directions and being electrically connected so that current will flow in the same circumferential direction throughout the coil.

Abstract: An improved coil construction for the voice coil motor of a transducer positioning system of a magnetic disk drive results in increased coil strength while eliminating the tendency of volatile materials associated with either the assembly process or the coil insulation to be entrapped between turns. Insulated aluminum ribbon wire having a rectangular cross-section is edge wound on a mandrel with adjacent turns being bonded together and then subjected to a curing process. By subjecting the ribbon wire to a knurling process prior to winding, the flat surfaces of the ribbon wire are provided with a plurality of knurl prints on each side which extend between opposite edges of the wire in a direction transverse to the lengthwise dimension of the ribbon wire. After winding, the knurl prints serve as interturn vents to prevent entrapment of any volatile materials generated during the curing process. The construction substantially doubles the tensile strength of the coil.