Abstract: An electromagnetic friction brake in which a friction pad on an electromagnet frictionally engages a rotating armature disc when the electromagnet is excited. The electromagnet is attached to a fixed mounting member by a pair of pins which project into holes in the electromagnet. The pins and holes are arranged such that one pin sustains all of the angular thrust which is imposed on the electromagnet by the armature while the other pin sustains no angular thrust and serves to retain the electromagnet radially of the armature. Such an arrangement of the pins serves to reduce accelerated wear which otherwise occurs at the leading edge portion of the friction pad.

Abstract: A direct current linear drive actuator including first and second electromagnets, each having a cup-shaped ferromagnetic stator core with an axially extending concentric annular main pole member on the centerline thereof. First and second independent stator coils are recieved within the annular recesses of the stator cores. The open ends of the stator cores face one another with a washer-shaped ferromagnetic common pole member, positioned intermediate the open ends in perpendicular relation to the stator main poles. The armature is spring biased to a neutral position and includes a disc-shaped permanent magnet configured for being received within the inner opening of the common pole and is sandwiched between first and second disc-shaped pole members, each having an overall configuration sufficient to overlap the perimeter of the common pole in the radial direction. Air gaps are formed between the stator poles and the armature poles.

Abstract: A preferred embodiment of a wire matrix print head assembly 10 is described having a housing 16 supporting a plurality of print wires 22 that are capable of moving between retracted nonprint positions and extended print positions for printing indicia onto a print medium. The assembly has a plurality of electromagnetic actuators associated with corresponding print wires 22 for rapidly driving a selected wire upon energization of corresponding electromagnetic actuator. Each electromagnetic actuator has a yoke 76 with five magnetically interconnected poles 84, 86, 88, 92 and 96 and two electrically interconnected coils 100 and 102 surrounding poles 86 and 92 respectively. Each electromagnetic actuator includes an armature 74 biased against and pivoting about an outer pole 88 to move an inner end against a print wire when the coils 100 and 102 are concurrently energized with the same directional polarity. Coils 100 and 102 are separated by the center pole 84.

Abstract: An electromagnetic acutator device for selecting needles in a knitting machine comprises two windings (3,4) positioned on opposite sides relative to an armature (5) in a support structure (2) made from a ferromagnetic material. The armature (5), which is also made from a ferromagnetic material, is hinged onto the structure (2), according to an axis substantially perpendicular to the axis of the windings (3,4) and is subject to the action of the magnetic filed generated by the windings (3,4) in order to be moved between two angular positions. The armature is hinged at one end engages a selection lever (11) at its other end, and has a configuration with two transversal portions (19, 20) protruding from opposite sides, and penetrating inside the interior of the windings (3,4).

Abstract: Disclosed is a dual working airgap force motor. A centrally located stator includes two toroidally shaped electromagnets wherein the axis of the stator coincides with the axis of the toroids, each toroidal coil is separated from the other toroidal coil by an axial distance. Toroidal permanent magnets are also mounted preferably inside the toroidal electromagnet coils and also spaced apart in an axil direction. The permanent magnets generate a flux flow in opposite axial directions whereas, upon energization, the toroidal coils generate flux flow in the same axial direction at a given radial position. Two armatures are located on an output shaft, in a preferred embodiment at either end of the stator, and each armature is spaced apart from the stator by inner and outer axial airgaps.

Abstract: The mechanism includes one member which may occupy one of two fixed positions and can be caused to change over from one position to the other at will. In order to accomplish rapid change over with minimum energy input and minimum impact, an elastic suspension of this member is provided and so arranged that the changeover process is substantially a half cycle of oscillation in which the moving member starts and ends with no or little speed of motion. The moving member is captured in the vicinity of, and held at the fixed positions, against the force exerted by the elastic suspension by mechanisms exerting short range forces upon it.

Abstract: An improved actuator assembly for an electromagnetically-actuated spring-loaded positioning system in displacement machines, such as for lifting valves in internal combustion engines. The positioning mechanism has a spring system and two electrically-operated, opposed actuating solenoids, by means of which the actuator may be moved between, and held at, two discrete, mutually-opposite operating positions. The improved actuator assembly of the invention comprises an actuator anchor plate secured to a guide rod which reciprocatingly engages a guide sleeve. The guide rod is moved back and forth by solenoids acting on the anchor plate, and comes into contact with a separate valve stem, by means of which the valve is opened and closed. The required tolerances for (a) the guideway for the valve stem, and (b) the guideway for the guide rod operating inside the electromagnetic unit, may thus be separately evaluated and selected.

Abstract: Apparatus and method for control of actuator anchor plate release time in spring-biased electromagnetically-actuated positioning systems for gas exchange valves in internal combustion engines in which a ferromagnetic actuator anchor plate is moved back and forth between two actuating solenoids. Pursuant to the invention, the poles of the solenoid core and the anchor plate are separated by a member which may be formed of an electrically-nonconductive, paramagnetic or diamagnetic layer, or an air gap. This provides magnetic resistance in the magnetic circuit which reduces generation and propagation of eddy currents in the anchor plate. The magnetic field can decay more rapidly upon cut-off of current to the solenoid coil. The release time of the anchor plate from the actuating solenoid is thereby diminished, and more accurate valve dwell timing is achieved for improved engine performance.

Abstract: An electromagnetic actuator includes a core structure defining a central pole piece and an annular pole piece surrounding the central pole piece in spaced relationship. A winding is provided which when energized causes the pole faces of the pole pieces to assume opposite magnetic polarity to draw an armature towards the pole faces. A further winding is located about the annular pole piece and an annular core component surrounds the annular pole piece in spaced relationship and extends beyond the pole faces to form a radial air gap 23 with the armature.

Abstract: An electromagnetically-actuated positioning mechanism for opposed spring-biased reciprocating valve actuators in displacement machines, having an electromagnetically-actuated adjusting solenoid device for shifting the locus of equilibrium of the actuators' spring systems at startup. While the position of equilibrium is predetermined when the adjusting solenoid is in the energized state, it is unnecessary for valves to be in the fully closed position when the adjusting solenoid is in the non-energized state. In the position of equilibrium as shifted by adjusting device, the distance of a gas exchange valve from one of the two operating positions is approximately 10% to 40% of the total distance between the two operating positions, and is at least partly open. The invention is particularly applicable to lifting valves and sliding gate valves, and for valves in internal combustion engines.

Abstract: A solenoid insulation system for an electromagnetic positioning mechanism for reciprocating valve actuators which are shifted between two positions by means of actuating solenoids and are maintained under load between their operating positions by a spring system. In the operational state, the locus of equilibrium of the spring system is determined by an adjusting solenoid which may be integral with or closely adjacent to the actuating solenoid(s). Pursuant to the invention, the adjusting solenoid's magnetic field is decoupled to the greatest possible degree from that of the actuating solenoids. In this manner, uncontrolled operating states of the actuating solenoid are avoided. Decoupling insulation is provided by suitable air gap(s), diamagnetic or paramagnetic material, or constructing the core of the adjusting solenoid from material different than the actuating solenoid, e.g., transformer sheet and sintered ferrite core material respectively.

Abstract: An electromagnetically actuable fuel injection valve, which serves to supply fuel to mixture-compressing internal combustion engines having externally supplied ignition. The fuel injection valve includes a base plate into which pole pieces having bent poles are inserted. Magnetic coils are fitted onto the pole pieces. A first permanent magnet is inserted between the poles and a second permanent magnet is disposed between the magnetic conductor elements disposed on the other end of the pole pieces. Beginning at the base plate, the magnetic coils and the pole pieces are provided with a sprayed-on plastic jacket. The plastic jacket is inserted together with the base plate into an internal housing bore of a valve housing.

Abstract: An electromagnetic linearly indexing actuator in which a shaft is mounted for linear motion in the direction of its axis. A pair of electromagnetic stator assemblies are carried in fixed position coaxially spaced from each other in the direction of the shaft axis. Each stator assembly has an associated armature which is slidably carried by the shaft, and a spring for urging each armature away from its associated stator. A latch is pivotally mounted at one end to each armature eccentrically of the shaft axis and has a central aperture which embraces the shaft. The stator assemblies are sequentially and alternately energized, so that the latches alternately grip and move the shaft during motion of the associated armatures. The shaft is returned to its initial position by a return spring, or by an opposing pair of armature and stator assemblies.

Abstract: An electromagnetic positioning system in displacement machines such as internal combustion engines in which spring-loaded valve actuators are shifted between two operating positions. Upon startup, the locus of equilibrium of the spring system is shifted by means of an adjusting solenoid which moves one of the spring system supporting seat members. The support seat member for the spring system is secured to and guided by a sleeve which, upon startup, is guided along the actuator rod. When the device is in its operating position, the actuator rod is guided in the sleeve. The working surface of the adjusting solenoid core has a beveled surface which assists in centering the sleeve in its operating position. The invention is particularly applicable to lifting valves and sliding gate valves, e.g., intake and exhaust valve actuators.

Abstract: A solenoid having a high degree of proportionality. A stationary pole is disposed within an electromagnetic coil and forms part of a flux path. An armature slides into and out of a bore of the pole and forms another part of the flux path. The armature has walls which define an axial recess formed in the armature face adjacent the pole. The armature walls have a cross-sectional thickness which decreases in a direction toward the bore. The walls of the pole bore have a cross-sectional thickness which decreases in a direction toward the armature. An air gap is formed between the decreasing thickness pole bore walls and armature walls which air gap remains substantially constant in the radial dimension as the armature slides.

Abstract: A transducer converts the amount of mechanical displacement of a member into an electrical signal by magnetic induction. Two fixed coils different in winding direction from each other are spaced apart from each other by a suitable distance and connected in series. Inside the fixed coils, a movable coil is disposed which moves in cooperative association with the member whose amount of movement is to be detected. With the movable coil supplied with an a.c. current, the fixed coils produce an induction current whose amplitude varies with the relative position of the movable coil. A signal processing circuit generates a pulse having a duty ratio corresponding to the amplitude of the induction current. This pulse is converted into a d.c. current in a smoothing circuit to obtain a d.c. voltage corresponding to the amount of mechanical displacement.

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: An electromagnet is proposed which serves in particular to actuate a fuel injection valve for fuel injection systems in internal combustion engines. The electromagnet includes a first pole piece disposed at one side of a first permanent magnet and a second pole piece disposed at the other side of the first permanent magnet. The pole pieces each have one conduction section bent at an angle, which sections are oriented toward one another and define a gap therebetween. Divided from the first permanent magnet by the conduction sections, a magnet coil is disposed on each pole piece. The first pole piece has a pole oriented toward the armature, and the second pole piece has a pole. When the magnet coils are not excited, the armature is drawn in the direction toward the poles by one component (.phi..sub.p2) of the permanent magnetic flux. If the magnet coils experience a flow through them of a current (i) in such a manner that an electromagnetic flux (.phi..sub.

Abstract: A magnetic flux-shifting or magnetic latch valve includes a first flux path including a first permanent magnet having a large coercive force so that its polarity cannot readily be altered. It further includes a second flux path including a second permanent magnet having a small coercive force so that its polarity can be altered. A valve according to this invention further includes a d-c source and a winding energized by said d-c source for altering the polarity of said second magnet.The fluid valve includes a valve element and a valve seat cooperating with the valve element. The valve has two limit positions, i.e. fully open and fully closed. In the fully closed position the pole surfaces of magnetic flux paths have the same magnetic polarity and hence do not attract each other permitting gravity, spring or hydrostatic means to form a gap therebetween.

Abstract: A solenoid having one or more windings, a plurality of alternate windings of which are connected in electromagnetic field bucking relationship. An alternative construction utilizes layers of bifilar windings. A first winding of each bifilar winding pair in a first layer is adapted to procduce a field to buck the field of a second winding in the same bifilar winding pair.

Abstract: An electromagnetic actuator is provided by a single armature plunger that reciprocally shuttles between two magnetic paths provided by a pair of coils. Undesired retarding-flux is cancelled in overlapping linkage paths through the plunger, yielding increased net magnetic force in the intended direction of movement and faster plunger operation. When either coil is energized, a primary flux path is created around that coil through the plunger, and a secondary flux path is created around both coils through the plunger. The primary path attracts the plunger to close a magnetic air gap. The secondary path holds the plunger in place. Current to the ON coil is also supplied through a limiting resistor to the OFF coil to generate reverse polarity flux in the latter cancelling secondary flux from the ON coil.

Abstract: An electromagnetically operating actuator for control elements capable of making oscillatory movements in displacement machines, more particularly for flat slide shut-off valves and lift valves, includes a spring system and a pair of electrically operating switching elements, over which the control element is movable in two discrete opposite operating positions and is retained thereat by either switching magnet, the locus of the position of equilibrium of the spring system lying between the two operating positions. The invention is characterized by the provision of a compression device in engagement with the spring system for relocating the locus of the position of equilibrium of the spring system upon actuation of the compression device.

Abstract: An actuator driven by D.C. power suitable for use in actuating automobile door locking device. The actuator has a yoke apparatus defining a space, two annular solenoid coils supported and received by the yoke apparatus and adapted to be energized simultaneously such that poles of the same polarity appear at the adjacent ends of the coils, and moving means reciprocatably disposed in the space of the yoke apparatus. The moving means includes an axially magnetized permanent magnet carried by a shaft and a pair of magnetic members attached to both axial ends of the permanent magnet.

Abstract: An electromagnet consists of two essentially symmetrically designed magnetizable E-shaped yoke halves each embraced by a coil. The facing pole ends of the yoke halves form three aligned operating gaps. Between the operating gaps a tongue-shaped ram is arranged which is shiftable in the direction of the line of alignment of the operating gaps. The cross-section of the ram is adapted to the area of the operating gaps. The ram comprises cuboid-shaped armature bars of magnetizable material. The armature bars are geometrically designed in such a manner that their volume is on the order of magnitude of the operating gap volume. In the original position of the ram the armature bars are essentially positioned in front of the operating gaps of the electromagnet. Upon excitation of the electromagnet, the armature bars are pulled into its operating gaps, being accelerated in the process.The windings of the coils exciting the yoke halves are essentially positioned between the E-legs of the yoke halves.

Abstract: A magnetic flux-shifting or magnetic latch valve includes a first flux path including a first permanent magnet having a large coercive force so that its polarity cannot readily be altered. It further includes a second flux path including a second permanent magnet having a small coercive force so that its polarity can be altered. A valve according to this invention further includes a d-c source and a winding energized by said d-c source for altering the polarity of said second magnet.The fluid valve includes a valve element and a valve seat cooperating with the valve element. The valve has two limit positions, i.e. fully open and fully closed. In the fully closed position the pole surfaces of magnetic flux paths have the same magnetic polarity and hence do not attract each other permitting gravity, spring or hydrostatic means to form a gap therebetween.

Abstract: This specification discloses a solenoid actuator which combines a fast response with a high force capability. A multitude of magnetic poles act in parallel to create a traction force which is a function of the number of magnetic poles and with fast dynamic response which is independent of the magnitude of the force and the size of the solenoid.

Abstract: A printing hammer as a movable member holds a magnet integrally therewith, yokes having coils wound thereon are disposed substantially at right angles with the direction of movement of the movable member and in opposed relationship with the magnet, and a printing member is disposed in the direction of movement of the printing hammer.

Abstract: The present invention relates to a control unit comprising a series of electromagnets for actuating juxtaposed or superposed mobile armature members. A cover locked in an frame contains a series of cores maintained in position by abutment of coil supports and by a plate. The latter supports a printed circuit connected to the coils and to a cable. The frame cover assembly is filled with a mass of injected resin. The invention is particularly applicable to textile equipment (dobbies).

Abstract: An electrical relay is provided with bifilar windings defining a first coil and a single winding defining a second coil. Each of the bifilar windings is connected in series with an RC network and this circuit is connected in parallel with the transmission line. When an AC current flows in the transmission line and through the bifilar windings and single winding, this does not cause the armature to move. When a DC current flows in the transmission line, it flows through the bifilar windings but is blocked by the RC network from flowing through the single winding which causes the leg of the armature to be attracted to the bifilar windings coil thereby operating the relay.

Abstract: The friction face of an electromagnet is formed by a relatively thin sheet of friction material and by magnetic inserts which are secured to the friction material and which define the pole faces of the magnet. The friction face is adapted to be easily removed from the magnet and replaced with a new friction face when the friction face becomes worn.

Abstract: A high efficiency bistable tractive solenoid device includes a magnetic housing having an interior cylindrical wall supporting stacked electromagnetic parts including a pair of coils and plural end pole pieces having inner diameters which are concentrically arranged to define a center bore. A double-acting plunger has an armature which is received by the center bore and is terminated by shaft ends having reduced diameters and being journalled for sliding movement in end plates also assembled within the housing interior wall with one of the shaft ends carrying a cam having a detent for latching the plunger in place.

Abstract: A linear magnetic motor/generator (10) is disclosed which uses magnetic flux to provide mechanical motion or electrical energy. The linear magnetic motor/generator (10) includes an axially movable actuator mechanism (12). A permanent magnet mechanism (14) defines a first magnetic flux path (16) which passes through a first end portion (18) of actuator mechanism (12). Another permanent magnet mechanism (20) defines a second magnetic flux path (22) which passes through a second end portion (24) of actuator mechanism (12). A drive coil (26) defines a third magnetic flux path (28) passing through a third central portion (30) of actuator mechanism (12). Drive coil (26) selectively adds magnetic flux to and subtracts magnetic flux from magnetic flux flowing in the first and second magnetic flux paths (16) and (22), respectively, for supplying an axial force to the actuator mechanism (12).

Abstract: Disclosed is a magnetically latching solenoid including a pull-in coil and a delatching coil. Each of the coils is constructed with a combination of wire materials, including material of low temperature coefficient of resistivity to enable the solenoid to be operated at cryogenic temperatures while maintaining sufficient coil resistance. An armature is spring-biased toward a first position, that may extend beyond the field of force of a permanent magnet. When voltage is temporarily applied across the pull-in magnet, the induced electromagnetic forces overcomes the spring force and pulls the armature to a second position within the field of the permanent magnet, which latches the armature in the pulled-in position. Application of voltage across the delatching coil induces electromagnetic force which at least partially temporarily nullifies the field of the permanent magnet at the armature, thereby delatching the armature and allowing the spring to move the armature to the first position.

Abstract: An electromagnetic device includes a stator having first and second closed flux-carrying paths defined by first and second cores, each having a plurality of concentric cylindrical pole surfaces and each defining an air gap opening between the outermost of the pole surfaces and the second outermost of the pole surfaces, with each core having at least one further pole surface. Coils are provided for generating electromagnetic flux in the first and second closed flux-carrying paths with the direction of flux flow across the air gaps being substantially radial with respect to the cylindrical pole surfaces. An armature defines a first and a second plurality of concentric cylindrical armature surfaces. The armature is mounted to be movable in a direction substantially parallel to the pole surfaces with each of the first and second cylindrical armature surfaces overlapping a corresponding one of the concentric cylindrical pole surfaces by an area dependent upon the position of the armature.

Abstract: An electromagnetic positioner for positioning the drive arm of an electrohydraulic servo valve or the like, comprising a mounting plate, a flexure tube secured to the mounting plate, a drive arm secured to the flexure tube, a top plate secured in parallel spaced apart relation to the mounting plate having a central opening therethrough, permanent magnets extending between the mounting plate and too plate, pole pieces secured to the mounting plate and extending toward the top plate on opposite sides of the flexure tube, control coils surrounding the pole pieces, and an armature positioned within the opening through the top plate in peripheral spaced relation thereto and secured to the flexure tube in spaced relation thereto and secured to the flexure tube in spaced relation to the pole pieces. Said electromagnetic positioner further including balance adjust structure, null adjust structure, and gain adjust structure.

Abstract: A bistable actuator comprising a magnetic member moveably mounted, in a housing of magnetic material, for movement between two positions. In each position such member is positively located adjacent a respective permanent magnet. Pole piece means is centrally located between the permanent magnets and extending from said housing to adjacent the moveably mounted member preferably extending to within a slot formed in the member. A separate coil is located within the housing between the pole piece means and each permanent magnet for energization to at least counteract the magnetic flux produced by the adjacent permanent magnet and allow movement of the member.

Abstract: Subject of the present invention is a compensating means for the mechanical losses and, or spring stresses in a universal impedance apparatus of electric power transmission and distribution use, the apparatus having a field and an armature coupled through a spring, with one or the other functioning as a mechanical oscillator. The means consists of a compensating winding deployed on the armature in tandem with the main winding and carrying an a.c. current in phase with the velocity of the oscillation, or a current additively proportional to both the velocity and the displacement of the oscillation.

Abstract: A conventional control valve hydraulically powered by a double acting cylinder and controlled electrically through a double acting solenoid supplied by a variable D.C. supply. The solenoid transmits varying forces to a four-way pilot valve which in turn controls the positioning of the double acting cylinder. The de-energized solenoid, control valve spool and pilot spool are neutrally balanced between two springs equally loaded with differing spring rates so that a small movement of the solenoid core will cause a proportionally larger movement of the main control valve spool proportioned to the different spring rates.

Abstract: A control mechanism for providing four separate linear control positions. Included is a lever having two ends, one end being free to register the four linear positions. First and second stationary solenoids both being located on one side of the lever are provided and the first solenoid plunger is pivotally secured to the lever at the end opposite the free end. The plunger of the second solenoid is pivotally secured to the lever between the ends of the lever. A stationary assembly including a spring is positioned and arranged to exert force on the lever between the first and second solenoids in a direction opposite the direction of solenoid plunger movement upon solenoid actuation. The spring force exerted on the lever is less than the combined force of the plungers of the first and second solenoids upon their common actuation. Separate spring force is exerted on the lever so that the lever is perpendicular to the plungers of the solenoids when both the first and second solenoids are deactuated.

Abstract: An electromechanical force motor including an elongate magnetic casing which coaxially enhouses a magnetic armature. An annular electromagnetic coil surrounds the armature and is axially positioned between a pair of permanent magnets having axially directed poles. A magnetic pole is positioned at each end of the armature in a posture juxtaposed to but spaced from the ends of the armature to provide a magnetic flux gap between the armature and poles. A pushrod is connected to one end of the armature and projects outwardly from the casing to produce work upon excitation of the electromagnetic coil.

Abstract: A high speed printer is provided having a plurality of aligned hammer assemblies for directing hammers at a moving character band for printing characters responsive to the hammer's driving against the character band. The hammer assembly has a striker arm pivotly mounted to a striker assembly frame and which acts as an armature when driven by a pair of magnets. The magnets are attached to the striker assembly frame on opposite sides of the striker arm and on opposite sides of the pivot point for the striker arm so that simultaneously actuating both magnets pulls the striker arm for actuating the hammer. Each magnet has a single coil, with one of the magnets having a reverse polarity from each adjacent magnet on an adjacent assembly, while the other magnet has the same polarity to avoid cross-talk and to increase the speed of the printer.

Abstract: An electromagnetic device comprises first and second relatively movable support members having surfaces presented to each other, electrical conductors mounted on the surfaces respectively, each of said conductors defining a portion disposed in side by side relationship with the portion defined by the other conductor whereby when electric current is passed through the conductors the magnetic fields generated will cause attraction or repulsion of said portions thereby imparting movement to said members.

Abstract: An electromagnetic device includes a stator having a first closed flux carrying path including a core and an air gap opening in the core. Flux is generated in the flux carrying path by a coil, with the direction of flux flow across the air gap being perpendicular to pole surfaces defining the air gap. An armature is mounted to be movable between the pole surfaces and to overlap varying areas of the pole surfaces in dependence upon the position of the armature. The overlap areas are directly proportional to the position of the armature. In one embodiment a bi-directional device having two such closed flux carrying path simultaneously acts on a single armature. The equilibrium position of the armature is dependent on the relative flux flow through the two flux carrying paths. A further embodiment is disclosed in which an air gap opening is inclined to the direction of flux flow in the core of the flux path. The area of each pole surface defining the inclined air gap exceeds the cross-sectional area of the core.

Abstract: An electromagnetic device comprises an annular member and a core member the latter having formed in its slots and the annular member having projections located in said slots. The projections and the adjacent wall of the slot define attraction faces which when a winding located in the slot is energized, are attracted towards each other thereby to produce relative movement between the members. The other faces of the projection are provided in accordance with the invention, with a coating of an electrically conductive material so that when the windings are energized eddy currents flow in the conductive material which act to assist the relative movement of the members.

Abstract: A pair of pancake-like coils have a coil axis substantially colinear with one coil mounted to a framework and the other coil mounted on a movable member. The coils are wound such that when electrically energized simultaneously the resulting magnetic fields are in opposition, thereby producing a repelling force therebetween. A spring is disposed between the framework and the movable member to urge the movable member in a sense opposite to the repelling force. A power supply is connected to the coil pair providing for a high initial energy transfer and a lower sustaining energy transfer. A shock absorber is mounted on the framework to arrest the moving member which is set in motion by the repelling force. An armature is attached to the moving member which enters the field of a holding coil as the moving member is displaced by the repelling force. When the holding coil is energized with the armature situated therein, the moving member is held against the spring force.

Abstract: Electromagnetic actuator, especially for actuating a hydraulic servo-control valve, which comprises a magnetic shell constituting a body of revolution and a concentric armature-forming permanent magnet, at least one annular field coil, the field coil and the armature being adapted to move axially in relation to each other. The movable member (field coil or armature) is caused to move by the resultant electromagnetic force resulting from the energization of the field coil to which a control direct current is applied and by the antagonistic force of a repulsion member incorporated in the magnetic shell. The field coil is longer than the armature so that the electromagnetic force is independent of the movement of the movable member and proportional to the control direct current. The movable member is caused to perform simultaneously a cyclic motion superposed to the axial movement in order to eliminate the friction hysteresis of the hydraulic valve.

Abstract: An electro magnetic device comprises a pair of relatively movable magnetizable members which have surfaces disposed in face to face relationship. One of the members is provided with spaced projections which locate in spaced slots formed in the other member, the projections having a smaller width than the slots so as to permit limited relative movement between the members. Some or all of the slots accommodate an electrical winding, the connection of the winding or windings being such that any two slots in which the flow of current in the windings therein is in the same direction are separated by a slot with either no winding or with a winding in which the flow of current is in the opposite direction. When the winding or windings are energized and when the projections are not centrally disposed in the slots, the members will be urged relative to each other to reduce the size of the smaller gap between each projection and the side face of the associated slot.

Abstract: A burglar alarm has a sound generating circuit which is actuated when the two magnets are moved away from each other. The sound generating circuit includes two coils of wire wound on a common core, and a permanent magnet hammering device which is actuated by the coils for sounding. When the two magnets are moved away from each other, a switch closes so that intermittent current can flow through one of the coils which repels the hammering device for sounding and releases it under the action of the other coil.

Abstract: An apparatus utilizing a flat plate type rotary transformer which has a rotary member with a collar fixed thereon, a stationary member provided with a bearing, the rotary member being mounted on the stationary member through the collar and the bearing, a first magnet core which is securely held on the rotary member and a second magnet core which is securely held on the stationary member. The magnet cores respectively of the rotary member and the stationary member are securely set by using the surface between the rotary member and the stationary member at which the members touch as the reference level in securing the desired gap between them.

Abstract: A solenoid includes a base formed with an external taper and an adjacent hub sleeve also formed with an external taper, the base and hub being joined by an alignment piece of non-magnetic material formed with a pair of internal tapers which are proportioned to mate with the external tapers of the hub and the base. The alignment insert assures and maintains a predetermined concentric coaxial alignment of the hub and base with respect to a common movable armature.