Abstract: A solenoid includes a ferrofluid in gaps between the moving and stationary elements which ferrofluid reduces noise caused by activating a plunger positioned within the solenoid. A permanent magnet can be included as a solenoid element to increase magnetic field strength within the solenoid to retain the ferrofluid within the solenoid.

Abstract: A switch device including an inner yoke and an outer yoke are arranged around the winding of an electromagnetic block, and a plate-shaped permanent magnet is inserted between the two yokes. A highly efficient actuation of the switching device is achieved by the assistance of the permanent magnet.

Abstract: A solenoid includes a ferrofluid in gaps between the moving and stationary elements which ferrofluid reduces noise caused by activating a plunger positioned within the solenoid. A permanent magnet can be included as a solenoid element to increase magnetic field strength within the solenoid to retain the ferrofluid within the solenoid. A cushion located between the plunger and a butt toward which it moves also reduces the noise, while the ferrofluid maintains a relatively high solenoid force relative to a solenoid with air gaps.

Abstract: An electromagnetic contactor includes an iron core members formed of a first core bent in a U-shape, and a second L-shaped core contacting the first core. A coil is wound around a spool disposed on an upper arm of the first core and the second core to form a main leg while a lower arm of the first core constitutes a yoke. Thus, the iron core members can be processed by a press machine operating at a normal cutting speed, and welding and polishing operations can be eliminated to thereby reduce the number of processing steps required.

Abstract: An electromagnetic actuator and an automatic recloser incorporating such actuator are disclosed. The actuator is shown to include a housing, a permanent magnet member, a coil, an armature, mounted to move axially within the housing between first and second positions, and a non-magnetic spacer. The armature, when in the second position, is spaced a distance from the housing by the spacer. The spacer is mounted to stop movement of the armature in the second position. In the preferred embodiment, the permanent magnet member includes a core and a number of magnet segments attached thereto. It is especially preferred for each of the permanent magnet segments to be arcuate shaped and that each segment be polarized substantially radially or in a direction parallel to the center radius of each segment.

Abstract: An electromagnetic active vibration actuator configuration combines two modes of operation to obtain the advantages of long stroke and linearity of voice coil type actuators and high efficiency of dual-gap solenoid type actuators. A coaxial stator shell surrounds an axially vibratable armature. Either the stator or the armature can carry one or more coils and/or permanent magnets, however usually the magnets are located on the armature for their contribution to vibrating mass. Alternate coils and alternate magnets are made opposite in polarity, the stator armature pole pieces being held symmetrically staggered relative to the stator pole pieces by end springs or flexures that allow axial vibration when AC is applied to the coils.

Abstract: A magnetically latching solenoid apparatus is characterized by a non-magnetic armature carrying a permanent magnet having poles aligned with the throw axis of the device. The poles of the magnet are substantially aligned with corresponding pole pieces and define respective variable air gaps therebetween. The apparatus assumes one of two bistable magnetically latched states according to the one of the air gaps across which the magnetic attractive force exceeds the magnetic attractive force across the other of the air gaps. Single or dual winding coils temporally excitable unidirectionally or bidirectionally and, in the case of dual winding coils mutually exclusively or contemporaneously, to cause the latch state to change.

Abstract: A magneto-mechanical power system including a cylindrical soft-iron vessel with permanent magnets arranged to form a shunt-magnetic gap with the inside wall the soft-iron vessel. The neck of the flux conducting disk is surrounded by a current winding. A magnetically attractable pole disk lies on the neck of the soft-iron vessel. An electrically conducting ring is fastened to the pole disk. The pole disk activates mechanical and/or electrical safety devices. The system is activated by a current impulse sent to the current winding. Current in the current winding creates a field that displaces the magnetic flux path of the permanent magnet.

Abstract: A microceramic linear actuator includes a unitary ceramic body which has been formed with an internal cavity; a piston mounted for linear movement within the internal cavity and having a micromagnet with first and second poles of opposite polarity, and at least one shaft attached to the micromagnet; a conductive coil embedded in the unitary ceramic body and having a first portion wound in a clockwise direction and disposed in operative relationship to the first pole of the micromagnet, and a second portion wound in a counterclockwise direction and disposed in operative relationship to the second pole of the micromagnet.

Abstract: A switching field for electromechanically switching electrical signal lines with crosspoints. The parts forming the crosspoints comprising membranes, at and between which further parts of the circuit are disposed. The switching field is particularly for communication and data transfer applications. The cross points are disposed matrix-shaped manner and signal lines assigned to the individual crosspoints. The crosspoints are composed of at least two contact surfaces which are movable relative to each other, to the one contact surface, a permanent magnet, and to the other contact surface, a ferromagnetic material with a coil assigned thereto.

Abstract: A control valve the controls the flow of a fluid. The valve has a housing with an inlet port, a cylinder port and a reservoir port. The inlet port is typically connected to a source of pressurized fluid. The cylinder port is connected to an actuator chamber and the reservoir port is connected to a fluid reservoir. The control valve has a solenoid that moves an internal valve between a first position and a second position. When the internal valve is in the first position, fluid can flow from the inlet port through the cylinder port. When the valve is in the second position, the inlet port is closed and the cylinder port is in fluid communication with the reservoir port. The housing has an internal channel that allows the supply fluid to apply a pressure on both sides of the internal valve. The fluid forces on the internal valve are opposite and offsetting, such that the solenoid force required to move the internal valve is independent of the pressure of the fluid.

Abstract: A self-holding type solenoid valve has an exciting coil 1 and an exciting circuit that switches the direction of flow of exciting current passing through the coil. When a positive exciting current flows through the coil, a movable iron core is attracted to a stationary iron core and held in the attracted position by a self-contained permanent magnet. When a reversed current flows through the coil, a return spring releases the movable iron core away from the stationary iron core.

Abstract: A bistable electromagnet is moved from one operating position into the other by a short direct-current pulse, the next pulse following in each case having the opposite current direction. The essential factor in this is a permanent magnet which is arranged in the core area and which holds the armature against the action of an armature spring in one operating position. An electromagnet constructed in this manner can be produced without tolerance calibration and requires less control power when the permanent magnet is carried freely movably between two end positions in the direction of armature movement in a hollow space of the coil core. The coil core can be constructed as a pot, at the bottom of which the permanent magnet is magnetically held whilst the permanent magnet is held in the other end position by a stop in such a manner that its side facing the armature is approximately flush with the edge of the pot.

Abstract: This invention discloses a D.C. magnetic latching solenoid that retains a moving armature in a first or second position by means of a pair of magnets, thereby having a zero-power requirement after actuation. The first or second position is selected by reversing the polarity of the D.C. voltage which is enough to overcome the holding power of either magnet and transfer the armature to an opposite position. The coil is then de-energized.

Abstract: An apparatus for dispensing viscous fluids, such as adhesives, sealants, caulks is actuated by an electromagnetic coil assembly (42,136) in conjunction with a magnet (38,126) mounted to a plunger (26,118). Energizing the coil assembly produces an electromagnetic field which cooperates with the magnetic field to cause the plunger to open. Closing results from reversing the electromagnetic field.

Abstract: The invention concerns a bistable magnetic drive with an assembled armature 3, 4 consisting of a high-grade, disk-shaped permanent magnet 3 with two appropriately shaped pole pieces 4,4' and displaceable sideways off the coil 1 transversely to its axis inside an electromagnetic annular pole-piece Rp between two electromagnetic stop pole-pieces 5, 5'. The invention describes illustrative embodiments and applications of this drive as an excursion and oscillating magnet, further a circuit for DC operation. A capacitor circuit furthermore allows mono-stable operation. The advantages are a lightweight armature, high efficiency, bilateral operation, versatility and simplicity.

Abstract: The solenoid (1) is of the type having a magnetic circuit (2, 3, 13) on which a permanent magnet (6) and an electric winding (7) would induce respective magnetic fields; the magnetic circuit has a stationary portion including a squared annular shroud (2) divided theta-like by a partition (3) which encloses, between itself and the shroud (2), the permanent magnet (6), on the one side, and the electric winding (7), on the other side, and a moving portion including a plunger (13) slidable axially within the winding (7) and being guided through an opening (12) in the shroud (2). The plunger (13) is movable between a retracted position and an extended position dependent on the magnetic field induced by the winding (7). The partition (3) comprises a flat plate on which the plunger (13) bears directly in its retracted position.

Abstract: An electromagnetic energy converter comprises a frame-like magnet core, a closed magnetic path being formed along the sides of the magnetic core, a winding wound around the magnet core and connected to a power supply or a load, an armature conductor having a frame-like body forming a closed electric circuit and having a portion of the magnet core passed therethrough, and a field magnet disposed so that the magnetic flux generated thereby passes through the magnet core and armature conductor. One of the winding, armature conductor and field magnet is movable with respect to the magnet core. Electric power is transmitted between the winding and armature conductor by electromagnetic induction, and conversion of electromagnetic energy takes place between the magnetic flux generated by the field magnet and the armature conductor through the displacement of the movable part.

Abstract: A latching solenoid device comprising an encasement, a portion of which is manually translatable in order to vary reluctance in a magnetic circuit which extends through the encasement, thereby providing the device with manual override capability.

Abstract: An actuator is provided with a position sensing system which comprises a permanent magnet, a saddle plate, a sole plate and the magnetically sensitive component. The magnet and the magnetically sensitive component are disposed between the saddle plate and the sole plate which are spaced apart for these purposes. A moveable plunger is arranged to move along an axis relative to a stationary stop member. A first magnetic circuit is provide which comprises the permanent magnet, the saddle plate, the sole plate, the stop member and the moveable plunger. A second magnetic circuit is provided which comprises the magnet, the saddle plate, the sole plate and a magnetically sensitive component such as a Hall effect element. In addition, an adjustment means can be provided within the second magnetic circuit to change the reluctance of that circuit for adjustment purposes.

Abstract: A bistable solenoid for use with a knitting machine. The bistable solenoid includes an enclosure made of magnetic material which includes bearing surfaces at opposite ends. A plunger having a central region made of magnetic material and outer end regions made of non-magnetic material is movable within the enclosure for operation of a cam of a knitting machine. The movable plunger is controlled by axially aligned permanent magnets which are spaced from each other by a yoke. The permanent magnets are sandwiched between magnetizable coils which move the plunger toward the coil that is excited. The plunger is spaced radially from the coil's magnets and bearing so that very little wear is brought about during use in operating the cam of the knitting machine.

Abstract: An apparatus for storing, feeding and measuring a weft yarn of a jet weaving machine is provided with an annular housing containing at least one weft yarn-stopping device. In said stopping device a stop member is arranged for a displacement between a passive position and a stop position. Said stop member is actuated by a current-energizable solenoid coil. Said stopping device is provided with a bistable and self-holding mounting arrangement for the stop member. Said stop member is connected with a polarized permanent magnet. For an actuation of the stop member in order to displace it away from its initial end position said current-energizable solenoid coil is electrically connected with a current-direction-reversing-circuit.

Abstract: The relay of the present invention is economically adapted for nuclear and commercial applications. The reliability of the relay is enhanced by utilizing a split coil and a permanent magnet located therebetween. The so-called split coil/permanent magnet configuration supplements the upward forces generated by a kickout spring by positioning a permanent magnet so as to assist in holding the armature and contacts rigidly in the off position. The design of the present invention assures that the armature stays in the desired position even when the relay is subjected to shock and vibration forces present in the environment.

Abstract: A solenoid actuator comprising a coil or coils of electrical wire and a plugnut and movable core within the coil(s). A magnetic yoke surrounds the coil(s), the axis of the latter extending across the magnetic circuit defined by the yoke. Relatively large and small permanent magnets are associated with the yoke on opposite sides of the axis, the magnets producing flux in opposite directions. A flux sensor, closer to the small magnet, senses changes in direction of the flux. When the core and plugnut are separated, the large magnet flux predominates throughout the yoke. When the core engages the plugnut, the small magnet flux predominates in its portion of the yoke, this change in flux direction being detected by the sensor. Thus, the sensor can be used to indicate the position of the core with respect to the plugnut.

Abstract: A control device for textile machines, in particular dobbies, has two magnet yokes with associated permanent magnets and an electromagnet, as well as an appropriately built magnet armature held in a first or second end position by the permanent magnet flux. When a current control pulse is applied to the electromagnet, however, the armature suddenly moves to the opposite end position, where it is again held until the next current control pulse moves it to the other end position. Only a very short current pulse is necessary to make the magnet armature change position. The resulting energy impulse is very intense and allows the holding and switching mechanical elements of dobbies to be directly controlled.

Abstract: A bi-stable electromagnet operator having an armature plate which is held in a first position by a permanent magnet and in a second position by a spring. An electromagnet is provided to enable the armature plate to move from the first position to the second position. The magnet has high coercivity and therefore the permanent magnet and core of the electromagnet can be in close magnetic contact both when the armature is in the first position and in the second position. The high coercivity of the permanent magnet provides for sufficient flux flow to maintain magnetization when the armature plate is in the second position away from the permanent magnet. Typically, the permanent magnet comprises neodymium.

Abstract: A latching solenoid which effects latching through a magnetic flux arrangement rather than a electromechanical latching mechanism. An electro-magnetic arrangement is used to move the solenoid from one latched position to the other.

Abstract: Bistable magnet, in particular for the actuation of valves and the like, with a movable piston that has a pole face and that is held by a permanent magnet in one of its two stable positions, wherein this piston has a stop face that is provided with a damping plate and that with an opposing face that is built stationary into the housing defines an end position of the piston. To avoid switching noises without decreasing the holding forces it is provided that, in addition to the stop face on the piston, a pole face is provided that interacts with a stationary pole face and that a device that guides the magnetic flux and bridges the air gap between these pole faces is provided between these pole faces.

Abstract: A bistable electromechanical transducer is disclosed having an armature reciprocable between first and second positions, a permanent magnet latching arrangement for maintaining the armature in the respective positions, and an electromagnetic repulsion arrangement operable when energized to dislodge the armature from the position in which the armature was maintained and causing it to move to the other of the positions. In a preferred embodiment, the transducer takes the form of an electronically controllable valve mechanism for use in an internal combustion engine and has an engine valve with an elongated valve stem along with the electromagnetic repulsion arrangement for causing the valve to move in the direction of stem elongation between valve-open and valve-closed positions.

Abstract: A bistable electronically controlled transducer having an armature reciprocable between first and second positions is disclosed including either a stressed spring or compressed air within a closed chamber in the transducer for causing the armature to move, and a permanent magnet latching arrangement for holding the armature in either one of the positions. An electromagnetic arrangement for temporarily neutralizing the effect of the permanent magnet latching arrangement releases the armature to move from one to the other of the positions. The transducer finds particular utility as an actuator mechanism for moving internal combustion engine valves.

Abstract: Relay drive for a polarized relay having an armature that can be moved in at least one working air gap provided between two pole faces of a split yoke and at least one permanent magnet, as well as a coil permeated with parts of the yoke, or a core directly connected therewith, wherein at least one pole face cooperating with the armature or located thereon is formed from one pole face of the permanent magnet and another pole face cooperating with the armature or disposed thereon is formed either by a pole face of another permanent magnet or of a soft-iron part, said soft-iron part being interchangeable with a permanent magnet of the same size.

Abstract: A head/arm lock mechanism includes a pawl mounted to the armature of a bistable solenoid, the armature being stable in either of two rotary positions. The armature and pawl are limited to move through an angle less than that defined by the stable positions of the armature, so that the armature is biased by the magnetic circuit of the solenoid to one or the other limit positions. When the head/arm is in position to be locked, the solenoid is energized to lock against a spacer on the head/arm and the magnetic circuit continues to hold the pawl in a lock-engaging position upon de-energization of the solenoid. When the head/arm is to be unlocked, the solenoid is again energized to unlock the pawl from the spacer and the magnetic circuit continues to hold the pawl in an unlock position upon de-energization of the solenoid.

Abstract: In the disclosed device, a pair of magnets supported in the ends of a C-shaped yoke bias an armature into one of the two rotary positions. A short pulse to a coil about the center of the yoke induces a short term magnetic field that supplements the polarity at one end of the yoke so as to either maintain the armature in its biased position or swing the armature to its other biased position. A subsequent pulse, producing a field in the opposite direction, returns the armature to its first position. In each case, the magnets retain the armature in its biased position even after the pulse stops. The armature pivots between portions of the yoke magnetized by the same magnet.

Abstract: The present invention relates to an improvement in an electromagnetic actuator which is composed of a yoke, a stationary core fixed to the yoke, a movable core capable of reciprocally moving with respect to the stationary core, a coil wound around the movable core for applying the first magnetic flux thereto when the coil is energized, and a permanent magnet fixed to the yoke or the movable core so as to apply the second magnetic flux which dividingly flows to the first magnetic flux in parallel thereto. This improved electromagnetic actuator is characterized that it satisfies the condition (a);(a) 0.5>R.sub.1 /R.sub.0 >0wherein,R.sub.1 represents the magnetic reluctance of the magnetic pass of one divided magnetic flux generated by the permanent magnet, including the magnetic reluctance of the gap d.sub.1 between one pole face of the movable core and one pole face of the yoke;R.sub.

Abstract: A polarized electromagnet with improved response sensitivity includes an axially movable core 63 extending through an excitation coil 61 to be movable between two positions upon energization and deenergization of the coil 61. The core 63 is formed at its opposite ends respectively with pole plates 69 extending transversely of the core axis. Inner and outer yokes 64 and 65 are arranged in parallel to the core 63 and are magnetized to the opposite polarities by a permanent magnet 65. Inner and outer yokes 64 and 65 have at respective ends inner and outer pole ends 67 and 68 which are spaced axially to each other so as to form therebetween magnetic gaps in each of which the adjacent one of the pole plates 69 is located.

Abstract: A magnetic actuator is disclosed in which a member formed of a magnetic material is movable relative to a frame along a predetermined path. Magnets are located on the frame at opposite ends of the path. In order to keep the mass of the movable member as small as possible, no magnetic elements are located on the member. Permanent magnets function with the magnets at opposite ends of the path to move the member, support the member along one degree of freedom, and hold the member in a rest position.

Abstract: A bistable electronically controlled transducer having an armature reciprocable between first and second positions is disclosed including either a stressed spring or compresed air within a closed chamber in the transducer for causing the armature to move, and a permanent magnet latching arrangement for holding the armature in either one of the positions. An electromagnetic repulsion motor overpowers the effect of the permanent magnet latching arrangement releasing the armature to move from one to the other of the positions. The transducer finds particular utility as an actuator mechanism for moving internal combustion engine valves.

Abstract: A valve actuating device for an internal combustion engine is operated with partial valve lift. The valve is spring biased toward a neutral central position but held in full open or closed positions by permanent magnets having associated coils. Normal activation of the valve between full open and closed positions is by activation of a coil to fully cancel the field of the associated magnet with a spring moving the valve to the other position. Partial lift operation comprises providing, with the valve in its closed position, a valve opening current to the valve opening coil to reduce the closing magnetic field but stopping the current before the valve reaches its full open position and providing a valve closing current to one of the coils to cause the return of the valve to its closed position.

Abstract: A magnetic latching actuator is disclosed having an arrangement of components which cooperate to minimize internal friction, while ensuring smooth and efficient operation. The invention uses a core having at least one electrical coil. In communication with the core is a permanent magnet. The magnet is positioned against a U-shaped magnetic flux connector having two parallel plates. The plates are sufficiently spaced from each other to permit the passage of a U-shaped armature therebetween. The armature is movable between the plates of the flux connector, enabling the transfer of magnetic flux to the armature while avoiding frictional engagement between the armature and flux connector. The armature further includes two end portions each designed to alternately engage the core at opposite ends.

Abstract: A bistable polarized electromagnet is provided having a mobile armature with a permanent magnet and pole pieces which cooperate with a fixed yoke through two pairs of air gaps for each of which one is variable whereas the other is substantially constant. This electromagnet may further have asymmetric or symmetric forms of revolution for easy replacement of the excitation coil.

Abstract: A valve member is latched into open or closed positions by permanent magnetic poles against the force of compressed springs. A coil associated with each position, when activated with a current, cancels the magnetic field of the permanent magnetic pole holding the valve member and allows the compressed spring to move the member quickly through a central neutral position toward the other position, whereupon it is attracted by the other magnetic pole to compress the other spring and latch into the other position. Variations on the basic invention include different structures for single valves, the inclusion of two valves within a single pair of coils with different opening current levels, and the use of the coil opposite the activating coil as a valve member movement sensing device.

Abstract: The magnetic drive of an electromagnetic contactor comprises two spaced coils (10,11) having a coaxial bore in which an armature (14) is mounted for reciprocal movement between two end positions. A control slider (21) is disposed between the coils (10,11) with its two sides forming stops for the armature (14). When the armature (14) is changed over from one to the other end position, the slider is also changed over and limits, at the mid-position, the return movement of the armature (14) from the respective end position. In a contactor designed for tri-stable operation, undesired movement of the armature beyond the mid-position is avoided, which could otherwise lead to an inadvertent change-over of the armature (14) to the other end position. If the contactor is designed for monostable mid-position operation, oscillation of the armature (14) about the mid-position is prevented, so that this mid-position is stabilized.

Abstract: A bistable actuating solenoid device having an axially translatable armature which is stable at either a first or a second position. The device employs a solenoid winding wrapped around a bobbin having an internal bore with the armature disposed in the bore. A permanent magnet is located at one end of the bobbin for holding the armature in the first position and a spring urges the armature toward the second position. When it is desired to move the armature from the first to the second position, a current is passed through the winding such that a magnetic field is generated which opposes the field presented by the permanent magnet to allow the armature to move to the second position under the influence of the spring. When it is desired to return the armature to the first position, a current is passed through the winding in a direction which generates a field which combines with that of the permanent magnet to attract the armature to the first position against the biasing force of the spring.

Abstract: According to the present invention, an electromagnetic actuator comprises a closed magnetic circuit consisting of a magnetic stationary member in a closed loop shape; an electric coil for energizing the closed magnetic circuit; and a movable member made of a permanent magnet, which member is bridgingly connected between a pair of restricted sections, facing each other, of the closed magnetic circuit through gaps so as to apply magnetomotive force to the closed magnetic circuit.

Abstract: A solenoid which is driven positively in both directions by reversal of coil current and held in place at either end by flux from a permanent magnet located at the center of the frame. The permanent magnet is formed of two opposed sections fitting tightly between the plunger tube and frame, and is located in a space between two coils. In one form the two magnet sections are formed of compressible material and are recessed to fit closely around the plunger tube.

Abstract: An electromagnetic actuator according to the present invention comprises(a) a casing mainly consisting of a stationary iron core (1) or a combination of a stationary iron core (1) and a yoke, (1b), the casing being formed with at least one of opening;(b) one or a pair of movable iron core (2) as an actuating member, capable of reciprocally moving through the opening of the casing;(c) an electric winding element (4) arranged in the casing for applying a first magnetomotive force to the movable iron core (2) when an electric current is flowed through the winding element (4);(d) a permanent magnet (5) being so arranged in the casing as to apply the second magnetomotive force to the movable iron core; and(e) a bias force generating means (3) for applying a mechanical force or the first magnetomotive force to the movable iron core (2), wherein the improvement is characterized that a permanent magnet (5) is so arranged in the casing as to apply the second magnetomotive force in parallel to the first magnetomotive f

Abstract: A polarized electromagnet device is constructed with a magnetic block movable within a specially designed yoke in response to the attraction forces of permanent magnets and an electromagnetic coil. The movable block and yoke designs form magnetic circuits which result in a relatively large permanent magnet attraction forces on the attraction side of the device and relatively small permanent magnet attraction force on the return side such that a spring load on the return side is not required.

Abstract: What is disclosed is an electromagnetic linear motion device having a pair of electromagnetic units mounted in spaced parallel position with a permanent magnetic armature between them. A gap is maintained between the units which is sufficiently small to permit most of the magnetic lines of flux generated by the units to pass along upper and lower plates forming each unit. The gap is sufficiently small, however, to prevent the magnetic cores of each unit from saturating and reducing the force generated by the device. The novel arrangement of the electric coils within each unit permits additional turns to be added for increasing the force generated by the device without increasing overall thickness.

Abstract: A bistable type of electromagnetic relay has a movable block including a pair of permanent magnet units. Each of the magnet units has a permanent magnet and a pair of generally U-shaped magnetic plates attached to its opposite poles. A rotation of the movable body actuates relay contact members. A yoke has opposite ends, each formed by a pair of opposing end pieces, the end of the magnetic plates being arranged in spaces defined by the opposing end pieces. A coil supporting a spool has a through-hole for receiving a core which is inserted therein. Flanges are formed at opposite ends and at a center portion of the spool, with a plurality of protrusions protruding outwardly on both sides of each flange. A pair of base members have grooves and recesses for receiving the protrusions on the flanges of the spool, for rotatably supporting the movable block.

Abstract: An electro-mechanical actuator has a ferrous alloy armature movably mounted within a body chamber. Two axially-spaced permanent magnets are arranged radially inwardly of the chamber and partially define the chamber at the ends thereof. A coil surrounds the chamber. The body is formed of a magnetically-permeable material. Because of the high reluctance of the magnets, each magnet forms a short magnetic loop which passes through the adjacent air gap, and forms a long magnetic loop which encircles the coil and passes through the distant air gap. The armature has a bistable toggle-like movement, and may be latched proximate either end wall. If springs are added between the armature and the body, the improved actuator may be used as a proportional position of force transducer within an operating range of armature movement.