Abstract: An air pump for use in combination with a household aquarium, the air pump comprising an electromagnet having an inner iron core, a coil arranged around the inner iron core, and a cylindrical outer iron core arranged around the coil; and a bellows unit having a permanent magnet whose magnetic pole is extended toward the inner iron core but spaced therefrom, and a diaphragm operated by the permanent magnet.

Abstract: A proportional pressure control device having a motor with a housing and a reciprocably movable armature oriented in the housing for movement between first and second limit positions. A valve body is secured to the motor housing. A platelike poppet valve member is secured to the armature on at least one end thereof. The valve body has a fluid pressure port thereon and it extends into the interior of the valve body to a chamber. A flow restrictor device is provided in the pressure port to restrict fluid flow from an external pressure source into the pressure port and the chamber. A nozzle outlet structure is provided in the chamber and has an annular flat valve seat thereon directly opposing the poppet valve member. The spacing between the valve seat and the poppet valve member effects a controlling of the magnitude of the fluid pressure developed in the chamber.

Abstract: Solenoid actuators which include a stator assembly comprising a plurality of spaced parallel poles having coplanar end faces and symmetrically spaced side faces. An armature is mounted for attraction to and motion with respect to said stator, at least a component of which is perpendicular to the coplanar stator pole end faces and parallel to the pole side faces. The armature comprises a generally flat plate having a surface in parallel opposition to the pole end faces, and a plurality of integral ribs which extend between adjacent pairs of stator poles and have side faces opposed to and parallel to the pole side faces. Thus, the air gap between the stator and armature has a variable dimension component between the pole end faces and the opposing armature, and a fixed dimension component between the rib and pole side faces. The resulting output power versus stroke characteristic exhibits high output power at the beginning of the stroke, followed by a substantially constant power versus stroke function.

Abstract: An electromagnetic pump comprising a housing having fluid receiving and pumping chambers in communication with an inlet and an outlet, respectively, an electromagnet carried by the housing external to the fluid chambers, and a barrier in the form of a thin diaphragm of fluid impermeable material which hermetically isolates the electromagnet from the fluid chamber. An armature in the housing is movable within a body of magnetically permeable material and has a pole portion located for magnetic attraction by the electromagnet and has a plunger portion in the pumping chamber for forcing fluid out of the chamber through the outlet. The armature is moved from a rest position through a forward pumping stroke when attracted by the electromagnet to force fluid out of the pumping chamber through the outlet, and the armature is moved by biasing spring in an opposite direction through a return stroke back to the rest position.

Abstract: A holder arrangement for the reciprocating rod of an electromagnetic reciprocator includes a reciprocating rod capable of reciprocating axially by magnetic action or the alternate combination of magnetic and spring actions, thereby effecting movement of a working member or members mounted at one end or both ends of said rod over a given stroke. In this arrangement, a flexible rod holder is disposed at a suitable position of a base to which an electromagnet is attached, said holder being provided with a flexible tongue piece for holding said reciprocating rod.

Abstract: A permanent magnet type stepping motor is provided. The rotor is made of a cylindrical laminated iron core whose outer periphery is toothed at an equal pitch, and the number of teeth is Nr. The stator is made of a laminated iron core whose inner periphery is formed so as to face the rotor at an air gap between the rotor and the stator. Thin plate permanent magnets are attached on the surface of the stator teeth facing the air gap. The permanent magnets are disposed at an equal pitch and polarized such that the polarities of adjacent pole pieces differ from each other. The number of pole pieces is Ns, and has a relation Ns=2(Nr.+-.Np), where Np is an integer more than 1. The stator grooves are half opened or closed and have multiphase 2 Np pole distributed windings.

Abstract: A reciprocating electric motor employs plural motor stator modules each including a group of coils selectively energized in subgroups to produce a magnetic field sweeping from one end of the group to the other and then repetitively from the same one end to the other always in the same direction until a number of ferromagnetic non-ferromagnetic armature sections each equal in length to the length of the stator modules and equal in number to the stroke of the motor divided by the length of each section has passed the stator module and thereafter the sequence of energization is reversed to move the armature a like distance in the opposite direction, the several coils of each group being electrically connected in a set each of which has its own power supply, the power supplies being collectively controlled by a microprocessor.

Abstract: A solenoid assembly comprising a magnetic plunger, an electric coil for generating a magnetic flux in a direction along an axis of the magnetic plunger, a main yoke composed of at least two separate members for defining a magnetic flux passage around the electric coil, and a pair of yoke end members held in engagement respectively with opposite ends of the main yoke, an outer casing. The yoke end members have recesses extending substantially normally to the axis of the magnetic plunger, and the main yoke has projections fitted respectively in the recesses to maintain the main yoke and the yoke end members in engaging relationship. The outer casing has an inner wall keeping the main yoke held in engagement with the yoke end members. A leaf spring acts on the main yoke to hold the latter securely in place in the outer casing. The yoke end members have cylindrical projections supporting thereon the electric coil between the projections of the main yoke.

Abstract: An electromagnet hammer of the type described in U.S. Pat. No. 4,215,297 is autosynchronized by triggering the discharge thyristor in response to the detection of the position of the armature by a proximity detector, or by direct detection of the zero passage of the negative amplitude of the discharge current, or at a reference point representing the position of the armature, with a delay equal to at least half the period of the natural period of oscillation of the armature/plunger and its elastic suspension.

Abstract: A linear stepper motor comprising a stator bar having stator teeth and a slider having slider teeth. The slider is positioned under the stator bar. The surface of the stator bar opposed to the slider has a pair of flat portions with a predetermined width between the edges and the teeth. The flat portions serve as rail portions for the rollers mounted on the slider. On the surface of the stator bar extending between the pair of flat portions are formed a plurality of parallel grooves to provide a plurality of stator teeth. The surface of thes stator bar is hardened by plating with a metallic material.

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 multistage resonant reciprocating compressor having opposed cylinders that are driven by a plunger unit. The plunger unit is suspended between a pair of spaced apart flexure springs and is electrically coupled to a linear motor mounted between the springs. The forces acting on the cylinder piston located on one side of the plunger unit are balanced against the piston forces acting on the other side of the unit and the stiffness of the flexure springs arranged so that the natural frequency of the plunger is at or near the exciting frequency of the motor.

Abstract: A bistable actuator comprising a permanent magnet assembly secured to an armature shaft and a pair of core elements axially disposed on either side of the permanent magnet assembly. The cores have axially opposed inner and outer annular extensions defined in each core by a central axial opening which supports the armature shaft and an annular recess in which is received an electrical coil. The permanent magnet assembly comprises inner and outer annular axially magnetized permanent magnets radially spaced by a ferromagnetic ring so as to be aligned with the inner and outer core extensions.

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 electro-magnetic stapling tool having a mechanism for adjusting the power with which the solenoid-operated plunger and the staple driver drive the staples. In its preferred embodiment, the power adjusting a mechanism includes a manually adjustable selector knob having a cam element, and includes a cam follower mounted in association with the upper end of the solenoid core. Rotation of the selector knob adjusts the length of the solenoid power stroke and the resulting driving power of the stapling tool.

Abstract: A two-directional percussion implement selectively adaptable both for driving in and for extracting, e.g. piles, from the ground, includes two coaxial electromagnetic coils whose movable armatures are represented by extremities of a reciprocable ram. Opposite anvils, one of which is adapted to be coupled with a driven element, are interlinked by a non-magnetic shaft traversing the ram. When the implement is intended for drilling operations, a rotary drive imparts rotation to one of the anvils via a connection permitting independent rotation and reciprocation. The shaft in this case has a central channel for taking samples or for conducting drilling fluids. When adapted only for axial percussions, the implement is vertically suspended on a cable via a shock absorber.

Abstract: Apparatus for producing linear motion comprising a coil defining an electromagnetic field across a gap; and a permanent magnet disposed within the magnetic field in the gap and arranged to be driven in motion by the magnetic field, the permanent magnet being configured such that its axis of magnetization lies along its smallest dimension.

Abstract: Apparatus for providing movement includes an electromagnet. The time required to attain a given value of current flow in a magnet coil is shortened by initially providing a higher voltage to attain quickly the desired current flow, and then providing a lower voltage.

Abstract: An electrically driven linear vibrator has swing drive for vibrating troughs, jarring tables or the like comprises a stator with an exciter winding, an armature guided for linear movement in a direction transverse to the field produced by the stator and a pair of oppositely acting return springs forming together a swing drive, the vibration of which may be used to drive a device connected to the vibrator. The return springs may be constituted by metal springs, gas springs or a combination of both. The swing drive may be constructed as single-acting or double-acting drives. A diode may be connected with the electrical conductors leading to exciter winding so that at a line frequency of 50 Hz, an oscillation frequency of 100 Hz, 50 Hz or 25 Hz may be obtained. The vibrator may also be provided with a piston blower for cooling the windings of the stator.

Abstract: A reciprocating electromagnetic pump, particularly but not exclusively for non viscous fluids, adapted to considerably reduce hum and heat loss, at the same time decreasing the electrical input, wherein the trunk piston of magnetic material, subjected to the unidirectional electromagnetic force produced by an AC-fed coil enclosing said piston, consists of a set of coaxial overlapping liners instead of a single piece. The higher is the number of these overlapping liners and the more considerable is the effect, which may be further improved if they are covered with an insulating adhesive before assembly and the cylinder for the piston is also made of magnetic material instead of the conventional non magnetic material.

Abstract: An AC or DC solenoid for operating a hydraulic or air valve, or another machine comprises a means provided at one end of an armature for reducing the effective cross-sectional area of a magnetic path extending through the armature and a yoke when the armature and a stationary core have a distance therebetween which is smaller than a predetermined fraction of the full stroke of movement of the armature. The solenoid is further provided between the armature and the stationary core with a means permitting them to be brought into axially overlapping relation to form a section of leakage flux therebetween. According to another aspect of the invention, there is provided novel means for securing a solenoid of the armature in tube type to a valve body. The improved solenoid has a small size, a long life, and superior performance without causing any excessive attraction over a given small stroke and generating any large noise.

Abstract: An electromagnetic device includes a stator having axially spaced pole pieces and windings which when energized cause adjacent pole pieces to have opposite magnetic polarity. An armature surrounds the stator and is of tubular form having a smooth internal surface. The exterior surface of the armature is machined such that at least at one end of the pole pitch distance of the stator the thickness of the armature is such that magnetic saturation of the material forming the armature occurs so that the lines of force between the armature and the pole piece extend in a direction inclined to the axis of the armature thereby resulting in a force acting to cause axial movement of the armature.

Abstract: A linear motor which utilizes the magnetic attraction between a washer formed from a ferrous material, e.g., steel, and a magnetic pole of an armature for automatically returning the armature to its original position upon the deenergization of a field coil. The washer is originally located in alignment with and in surrounding relation to one of the effective poles of the armature. The stroke of the armature is limited to a distance which insures that at the end of the stroke the one effective pole will be located closer to the washer than any other effective pole. Upon deenergizing the field coil, the magnet attraction between the one effective pole and the washer will cause the armature to return to its original position.

Abstract: A solenoid-actuated hydraulic fluid pump having a reciprocable armature operable by a magnetic circuit and with dashpot structure to limit movement of the armature beyond a predetermined position to avoid noise-creating contact with another part of the pump.

Abstract: A linear electrodynamic machine is disclosed having permanent magnet excitation and an end flux leakage control. A flux carrying body having a plurality of annular magnets of alternating radially oriented polarities is disposed concentrically with respect to a stator having a plurality of annular wound coils. Relative axial reciprocation of the body and stator causes a reversal of the flux linking the coils while the flux in the body remains substantially constant. Focusing magnets provided on each end of the body and axial extensions provided on the stator insure uniformity of the alternating flux linking the coils and a constant flux intensity in the body to achieve high efficiencies.

Abstract: Apparatus for producing linear motion comprising a coil defining an electromagnetic field across a gap; and a permanent magnet disposed within the magnetic field in the gap and arranged to be driven in motion by the magnetic field, the permanent magnet being configured such that its axis of magnetization lies along its smallest dimension.

Abstract: Photographic camera light controlling apparatus for driving a light admitting system, comprisingfour stator electromagnetic poles defining therebetween an intervening field space containing a linear path, including first and second transversely opposed poles at one path end and third and fourth transversely opposed poles at the other path end, with said first and third poles on one path side and second and fourth poles on the opposite path side,a field coil mechanism energizable alternately in opposite current flow directions and coordinated to energize said first and fourth poles with one polarity and said second and third poles with the opposite polarity, and alternately vice versa, thereby providing in such field space oppositely polarized electromagnetic fields,a permanent magnet for driving such system, having its permanent poles arranged transversely of the path and forming a surface magnetized permanent magnet with one permanent pole facing said first and third poles and the opposite permanent pole fac

Abstract: An electromagnetic device comprises a stator structure and an armature surrounding the stator structure. The stator structure is provided with axially spaced pole pieces which are of annular form and between which are located electrical windings connected so that adjacent pole pieces have opposite magnetic polarity. The armature has complementary pole pieces and when the windings are energized the armature will move relative to the stator structure. In order to facilitate construction of the device the stator structure is formed as a plurality of portions each of which has a cylindrical portion and a rim portion. The armature is formed as a stack of annular portions each of which includes an inwardly extending pole piece. The device is constructed by assembling the armature and stator structure alternately and in sequence.

Abstract: A solenoid-actuated fluid pump having reciprocable armature operable by a magnetic circuit and with structure in the flux path at the upper and lower air gaps to substantially change the reluctance across the air gaps as the armature moves beyond a predetermined location. The armature has slots for passage of fluid therethrough and which have a C-shaped cross-section to minimize the air gaps.

Abstract: A variable reluctance type firing sensor is mounted on an air gun for providing an electrical signal indicative of the instant of firing of the air gun. The firing sensor has a magnetic circuit which includes a permanent magnet, a pair of pole pieces and an armature including magnetically permeable material and which is free of mechanical restraint in its normal operating position, being held by magnetic attraction in position in the magnetic circuit. The armature freely "floats" on its "magnetic springs" within a thin walled chamber in which it is housed between the pole pieces, assuming a predetermined position of least magnetic reluctance. The armature which is acceleration-responsive is suddenly displaced from its predetermined position upon the firing of the air gun, and thus the reluctance of the magnetic circuit abruptly increases at the instant of firing.

Abstract: An electromagnetic actuator comprising a housing of magnetizable material defining a stationary pole, a bobbin supported by the housing and having an interior bore, an armature comprising a permanent magnet provided with a pair of magnetic poles and movably supported by the bobbin, a pair of coils circumposing the armature and having wire end portions and means securing the wire end portions to the bobbin. The bobbin comprises a pair of bobbin sections and means connecting the bobbin sections, each bobbin section having an inner and an outer rim and supporting one of the coils between the rims. A collar section integrally connects each of the bobbin sections and comprises a keeper for securing the wire end portions and a radially extending vent bore.

Abstract: A spring-less linear actuator, especially useful as a print wire drive. A permanent magnet armature is driven from a rest position on a pole piece by magnetic repulsion upon energization of a solenoid by a D.C. pulse. The armature is fixed to a print wire which rebounds from a printing medium, thereby returning the permanent magnet toward the rest position, where it is held, without bouncing, by the magnetic attraction between the armature and the pole piece of the solenoid, which is now de-energized.

Abstract: An electromagnetic device comprises an outer annular member and an inner member, the two members each having a helical rib on their presented surfaces. Two presented side faces of the ribs define working surfaces and on one of the working surfaces is defined a groove which extends the length of the rib and the groove accommodates an electrical winding which when energized creates a pair of magnetic poles on the one working surface. The magnetic circuit of the poles includes the other working surface and the two surfaces move towards each other to reduce the magnetic reluctance thereby causing relative movement of the members.

Abstract: The present invention relates to a dynamo-electric machine which includes a plurality of permanent magnets arranged sequentially with like poles adjacent and spaced from each other by a plurality of spacers of magnetically soft material. Motive coils are located generally adjacent to the permanent magnets so that when energized one pole of the induced magnetic field will provide attractive forces toward one of the permanent magnets while the opposite pole of the induced magnetic field will produce repulsion forces from the like pole of the adjacent permanent magnet. A commutator device is provided for properly energizing selected ones of the motive coils in proper polarity. A plurality of generator coils are located adjacent to the permanent magnets for cutting the magnetic lines of flux emanating therefrom so as to generate an induced voltage at an output thereof responsive to the relative motion between the generator coils and the permanent magnets.

Abstract: A linear motor construction in which a plurality of parallelpiped shaped permanent magnets are retained within an easily molded spool having an axial bore formed through the axis thereof. A coil which may be electrically excited is wound about the spool and produces a magnetic field when excited, which reacts with the field produced by the permanent magnets to cause linear motion in a ferro-magnetic, cylindrical armature which is slidably contained within the axial bore.

Abstract: An electromagnetic hammer has a coil coacting with an axially reciprocable armature including a ferromagnetic core traversed by an elongate nonmagnetic ram which carries at one end a spring-loaded piston head forming part of a pneumatic damping device, its other end co-operating with a working tool. The coil is intermittently energizable by a control system including a capacitor chargeable from an electric power supply by way of a first thyristor and dischargeable through the coil by way of a second thyristor, the two thyristors being sequentially triggered in response to a control pulse applied to a transformer with two secondaries generating staggered firing pulses with the aid of a delay network in the output circuit of one of these secondaries.

Abstract: A method for forming a magnetic core for the magnetic circuit of a linear-motor compressor suitable for use in a refrigerant system. The compressor includes a conical armature which reciprocates in a complementary air-gap under the influence of an electromagnetic circuit and a pair of linear complementary return springs connected to the armature between the compressor piston and outboard bearing. The electromagnetic circuit includes a pair of abutting convoluted loops of spirally wound magnetic strip material with a conical air-gap fabricated in the area of abutment. The magnetic core is formed by forming a pair of stacks of magnetic strips having diverse lengths, bending each stack to form a generally C-shaped core section having a generally semi-circular air-gap space defined by the ends of the strips, fastening the C-shaped stacks in opposed abutment to form a generally cylindrical air-gap, and then machining the air-gap into the desired conical shape.

Abstract: An energy conversion apparatus is disclosed in which a stator, fixed relative to a watertight housing, is coupled to a rotor by a helical spring which suspends the rotor from the housing. Natural turbulence of a fluid, such as water or air, causes acceleration of the housing, and hence, acceleration of the stator. Inertia of the rotor, coupled to the stator through the helical spring and the housing, causes relative motion, both longitudinal and rotational, between the stator and the rotor, the rotational motion between the rotor, and the stator being used to generate electrical current.

Abstract: A moving-iron, linear-motor compressor suitable for use in a refrigerant system, wherein a conical armature reciprocates in a complementary air-gap under the influence of an electromagnetic circuit and a pair of linear (constant rate) complementary return springs connected to the armature between the compressor piston and an outboard bearing. The armature rod is made of magnetically permeable material. The electromagnetic circuit includes a pair of abutting convoluted loops of spirally wound magnetic strip material with a conical air-gap fabricated in the area of abutment. The motor has a layered construction which cooperates with the conical armature and air-gap such that the motor is self-aligning at the assembly stage.

Abstract: An axially polarized bar magnet is slidably disposed in a non-conductive, non-magnetic tube on which two serially connected oppositely wound induction coils are disposed, the coils being spaced apart by a distance less than the effective length of the magnet.

Abstract: A mechanical vibrator or tapper is shown in which a high intensity permanent magnet armature moves within the field of a coil of wire wound about the magnet. The magnet is guided for reciprocal motion within a spool containing the winding and strikes impact pads at opposite ends of the central spool opening. The magnet consists of two permanent magnets bonded to one another with like poles facing one another and is freely movable within the spool opening and is guided therein. A permanent magnet is fixed at one end of the spool opening and forces the permanent magnet assembly to reverse its motion after the magnet field of the winding drives the armature magnet against the impact pad at that end of the spool opening, and the magnetic field of the coil goes to zero. An oscillator circuit for driving the system is contained on printed circuit boards mounted within the housing which encloses the vibrator structure. The housing is crimped together in its final assembly.

Abstract: A vibratory feeder system includes a track having a linear, circular or helical configuration upon which articles that are to be transported are positioned. The vibratory feeder system further includes a support structure for supporting the track. The track and support structure are joined by resilient members of a configuration and dimension such that the track may move in a generally linear, reciprocative path relative to the support structure. The vibratory feeder further includes one or more self-contained, inertial drive elements wherein each drive element includes a rigid, nonmagnetic, cylindrical housing having end covers. Two iron stator cores are rigidly mounted within the housing and to the interior of one end cover thereof. Two resilient members having mounted at one end thereof a reciprocating armature are secured to the one end of the housing. A laminated iron armature core positioned so as to be spaced from the stator cores by an air gap is mounted on the armature.

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 compact electric generator that is powered by a tensioned spring and adapted to serve as an integral and permanent source of electric energy for a photographic camera or other apparatus. The generator includes a permanent magnet, a pole piece and a reciprocally-movable armature that define a magnetic circuit. The permanent magnet is also movable with respect to the pole piece and armature and is so oriented, when the generator is cocked, that the field strength of the magnetic circuit is sufficient to permit the pole piece to magnetically "capture" the armature and hold it in a predetermined position against the action of the tensioned spring. The generator is tripped by displacing the permanent magnet and thus weakening the field strength of the magnetic circuit. This permits the tensioned spring to overcome the magnetic "lock" on the armature and rapidly propel the latter away from the pole piece.

Abstract: An electromagnetic device comprises a pair of a plurality of pairs of helical coils the turns of the coils being alternatively arranged. Each of the coils is formed from a length of tubular magnetizable material and within each coil is an electrical conductor. The conductors in the turns of adjacent coils carry electrical current in opposite directions and the walls of the coils which are adjacent each other are of reduced section so that when the conductors carry electrical current, magnetic flux leakage occurs and the turns of the coils separate thereby producing an extension of the coils which is transmitted to a pair of members.

Abstract: An hydraulic plunger for cleaning a clogged drain composed of a casing with a piston movable therein and being open at one end. A fitting is provided on the open end that fits against the drain inlet. A water inlet is provided in the casing to permit water to fill the casing on the side of the piston that is open to the drain pipe and the drain pipe to the stoppage therein. An electromagnetic unit is carried within the casing and has a driven member that strikes the piston to create a relatively large impact force against the water and stoppage in the drain.

Abstract: A linear actuator comprises a toothed magnetic motor bar and a motor element having a pair of E-cores on opposite sides of the motor bar. Rollers attached directly to the E-cores ride on the motor bar to maintain a fixed air gap between the motor bar and the pole faces of the E-cores. The E-cores are connected by I-shaped connector plates to hold the tooth relationship between E-cores. The connector plates also are flexible to compensate for variations in thickness of the motor bar.

Abstract: A collision detecting system is mounted on the front part of an automobile to detect collisions thereof and comprises a permanent magnet, a generating coil and a plunger as its principal component elements. In the system, the plunger in bar form is composed of a magnetic material and it is extended through and displaced within a space which is defined by the cylindrical permanent magnet and disk pole pieces provided at each end of the permanent magnet and having central openings, and the generating coil is mounted in the space to provide a magnetic circuit along with the plunger and the permanent magnet.

Abstract: An electromagnetic actuator having a plunger core and a stationary ferromagnetic core, both surrounded by an electrical winding, is provided with means for adjusting the axial position of the stationary core in relation to the winding, said means being operable from outside the actuator.

Abstract: A linear signal generator, that is one operating axially as opposed to a rotating generator comprises a housing, an annular electric coil mounted about the longitudinal axis of the housing, a permanent magnet resiliently mounted for movement along the longitudinal axis of the housing through the annular coil, and means for removably latching the magnet at one end of the housing. The magnet is preferably resiliently mounted to a plunger which is depressible a sufficient amount to cause the magnet to pass into the coil and latch at the opposite end of the housing, such as by a magnetic latch. When the latching force is overcome, such as by release of the biased plunger having a biasing force in excess of the magnetic latching force, the magnet is rapidly axially propelled through the electric coil to a rest position at the opposite end of the housing where the cycle may again be repeated.