Abstract: A reciprocating compressor includes an electric motor having fixed and moveable components within a housing for reciprocating a moveable assembly, to compress a working fluid within a variable volume compression chamber within the housing. An integrated flexure spring and circuit connected between the housing and the moveable assembly axially and radially centers the moveable assembly within the housing, and additionally, supplies an electric current to a moveable current coil of the electric motor associated with the moveable assembly. The moveable assembly is axially reciprocated against a restoring force of the integrated flexure spring and circuit responsive to an axial force exerted on the moveable assembly by the electric motor when the electric current is supplied to the moveable current coil via the integrated flexure spring and circuit.

Abstract: A rotary torque-to-axial force energy conversion apparatus employs a rotatable member, a translatable member, and a magnetic coupling therebetween. The magnetic coupling converts a rotary torque on the rotatable member to an axial force on the translatable member, and includes a first permanent magnet comprising part of the rotatable member and a second permanent magnet comprising part of the translatable member. By way of example, the first permanent magnet and the second permanent magnet may each comprise interleaved, helical magnet sections of alternating polarities. A significant application of the energy conversion apparatus comprises an actuator apparatus for a ventricle assist device (VAD) or a total artificial heart (TAH). By oscillating the drive motor energizing the rotatable member, an oscillating rotary torque is achieved that is converted by the magnetic coupling to a reciprocating axial motion on the translatable member.

Abstract: An electric pump including a linear motor consisting of a stator and a moving element driven by the electromagnetic field generated by the stator, and a pump piston driven by the linear motor, is disclosed. The piston is arranged inside the stator of the electric pump and forms the moving element of the linear motor. An oil well facility provided with such an electric pump is also disclosed.

Abstract: A vacuum pump contains two rotary displacement rotor (8) that engage each other, in particular in a convoluted manner, inside in expansion chamber through which flows a stream in the axial direction. The rotors are mounted in cantilever at the delivery side and are linked each to a driving motor (35, 36). Each rotor (8) forms together with its shaft (20), a stationary bearing body (7) and a bearing (21, 22) delimited by the shaft (20) and the bearing body (7) a module that may be removed as a single unit from the housing (3). The rotor (35) of the driving motor is preferably also part of said module.

Abstract: A positive displacement inductive pump which includes a pair of steel cylinders or sleeves having a non-magnetic corrosion resistant inner surface and non-magnetic alloy rings disposed at each cylinder end. Three ferromagnetic pole pieces having an axial opening are provided with each cylinder disposed between a respective pair of the pole pieces and connected to the pole pieces with the alloy rings. A pair of oppositely disposed steel plates connected to the pole pieces forms a magnetically conductive circuit between the pole pieces. A piston positioned within the bore defining a displacement chamber adjacent to each end of the bore. The piston includes a rod formed of magnetic material with a corrosion resistant lining encapsulating the rod. The pistons outer lining surface forms a seal with the material on the inner surface of the cylinders.

Abstract: The invention relates to an apparatus for generating signal pulses with a gear arrangement, which has at least two meshing gears and with a sensor means for detecting a gear rotation and for emitting signal pulses as a function on the detected gear rotation. According to the invention a sensor of the sensor means is located in the vicinity of the gear arrangement at a point where the sensor detects the rotation of both gears.

Abstract: A diaphragm pump including a reciprocating piston engaging at opposite ends a pair of diaphragms which close opposite ends of a cylinder is disclosed. The piston ends engage the respective diaphragms across the entire dimension of the cylinder so that the membranes act as seals between the piston and the cylinder, thereby preventing unequal distortion of the diaphragm and enabling the pump to generate high pressure.

Abstract: A magnetically-powered linear displacement device is disclosed which can be used as the highly efficient pollution-free prime mover. The linear displacement device utilizes a permanent magnet whose flux density can be readily shifted from one of two parallel magnetic paths within the displacement device. A pair of pole pieces made of magnetically soft material abuts portions of the permanent magnet and conducts the magnetic flux in two different magnetic circuit pathways such that the permanent magnet's flux can flow in either direction, and if the magnetic flux is travelling along a first of these parallel paths through a movable armature, that armature will be attracted toward the ends of the pole pieces. If the magnetic flux is then shifted to the second path of these two parallel paths, then that movable armature will not be attracted to the pole pieces, and a compression spring can be used to push that movable armature away from the pole pieces.

Abstract: The modular linear motor includes at least a pair of like stator modules and at least a pair of like mover modules. A stator module coupler interconnects the like stator module and has an axial length of sufficient dimension to maintain a given three phase stator pole pitch between the interconnected stator modules. A mover module coupler interconnects the like mover modules, and has another axial length of sufficient dimension to maintain a given mover pole pitch between the interconnected mover modules.

Abstract: The device permits the precise guiding and centering of machine elements, for example of a piston rod (7) or a piston (3,4) in a cylinder (5,6). Therein two guides (11,12) are disposed at approximately right angles to the longitudinal axis (2) of the piston rod (7) and at a distance from each other. Each guide (11,12) comprises several spring elements (15) which extend radially from the axis (2). The spring elements (15) comprise long main spring parts (16) and short auxiliary spring (17). The spring parts (16,17) are rigidly connected one with the other via connection parts (18). The guides (11,12) have with respect to the axis (2) high transverse rigidity and permit precisely guided oscillating motions of the machine elements (3,4,5,6,7) along the longitudinal axis (2). These guides (11,12) permit for example the contact-free relative motions between piston (3,4) and cylinder (5,6) and have a high service life and operational reliability.

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

Abstract: An apparatus powered by solar cell photon energy having a motor for rotating a drive shaft by the use of compressed air. The motor comprising: a housing having a circular cross section with a drive shaft extending therethrough; a rotor having concave cups on its exterior surface mounted on the drive shaft within the housing; ports extending through the housing to cause rotation of the rotor; a plurality of sources of compressed air positioned adjacent to the housing. The apparatus further includes an alternator and/or a system for converting solar energy into mechanical energy comprising a battery chargeable through solar panels to generate power for reciprocating pistons to thereby generate the compressed air.

Abstract: A positive displacement inductive pump includes a housing having first and second ends, and a bore extending from the first end to the second end. A piston is positioned entirely within the bore and defines at least one substantially enclosed displacement chamber. The piston includes a metal rod, and a corrosion resistant lining that completely encapsulates the metal rod. First and second inductive coils are each wrapped around an outer circumference of the housing and are each alternatingly energizable to produce respective first and second induced magnetic fields causing metal piston to move to oppositely located first and second positions within the bore. At least one check valve assembly is attached to one of the first and second ends and is in communication with the at least one displacement chamber.

Abstract: A hydraulic pump has a magnetic tube and two floating pistons within the tube, adapted to be moved in an axial direction within the tube as a result of magnetic flux generated by an electric coil surrounding the tube. Each piston has a valve for allowing fluid flow in one direction through the tube, and spring means acts on the pistons to control their positions. The arrangement allows operation with reduced vibration and pressure fluctuation, less heat and impact during dry running operation, and less heat and impact during high pressure shut-off.

Abstract: A micro-pump having a cross-sectional area of not more than 5 mm.sup.2 and usable as a drive source for the operation of a micro-machine and as the controlled flow of a fluid and a method for the production of this micro-pump are provided. The micro-pump is characterized by comprising a comb-shaped stationary electrodes, a fluid chamber, a piston formed in the fluid chamber, comb-shaped movable electrodes formed integrally with the piston, a conductive film for imparting a grounding potential to the piston and the comb-shaped movable electrodes, and check valves and consequently having a drive source integrally formed therein.

Abstract: This invention relates to linear motor compressors which operate without the use of oil and a gas bearing while providing a flexible suspension for such a compressor. Such structures of this type, generally, provide a highly reliable oil-free compressor for use with cryogenic refrigeration equipment so as to attain unattended, continuous operation without maintenance over extended periods of time.

Abstract: An electrohydraulic apparatus (1) transmitting motion from one location to another utilizes a pair of linear motor assemblies (111, 113) to impart motion to respective hydraulic means (115, 117) providing continuous fluid flow performing work at a work station (119), hereby providing an improved electrohydraulic apparatus and method for performing work.

Abstract: This invention relates to balanced linear motor compressors which operate without the use of oil and externally tuned resonant balancers. Such structures of this type, generally, provide a highly reliable oil-free compressor which is internally balanced for use with cryogenic refrigeration equipment so as to attain unattended, continuous operation without maintenance over extended periods of time.

Abstract: This invention relates to linear motor compressors which operate without the use of oil. Such structures of this type, generally, provide a highly reliable oil-free compressor for use with cryogenic refrigeration equipment so as to attain unattended, continuous operation without maintenance over extended periods of time.

Abstract: A new and improved linear motor-pump assembly and method of using it for downhole use. The assembly includes a cartridge unit with a linear motor attached threadably between a discharge housing assembly adapted to be secured removably to a cable for hoisting the cartridge unit through the production tubing of a well and a suction housing assembly for facilitating the pumping of well fluids from a downhole well. The linear motor includes a mover adapted to engage threadably a stop valve for permitting one-way flow of fluid through the mover and into the discharge housing for discharge into the production tubing. For increased pumping efficiency, the suction housing and check valve are replaceable with a lifting pump and piston respectively. Thus, the assembly is usable in both shallow and deep wells.

Abstract: A hydraulic engine apparatus and method that converts pulsed electromagnetic energy into mechanical force and motion. The engine apparatus produces usable mechanical power by pumping action made possible by a reciprocating piston in a cylinder acting on a fluid that is responsive to the pulsed electromagnetic energy. The cylinder is provided with check-valved input and output ports at both ends of the cylinder, which output ports are hydraulically coupled to a hydraulic motor for delivering mechanical power from the hydraulic motor's output drive shaft. The piston has embedded permanent magnets that coact with the pulsating electromagnets to produce the reciprocating action. The piston permanent magnet has prodruding ends which are received within central bore portions of core members of the electromagnets for producing increased magnetic pull.

Abstract: An electromagnetic reciprocating pump which maintains the outlet pressure at a preset value comprising a pressure sensor for detecting the actual outlet pressure of the electromagnetic reciprocating pump and means to feedback control the frequency of the reciprocating motion and, if necessary, its stroke of the electromagnetic drive means based on the deviation from the preset outlet pressure of the actual outlet pressure. The reciprocating motion frequency control of the electromagnetic drive means may be done by modulating the frequency and amplitude of the half-wave AC current supplied to the electromagnetic drive means. With this, the control of the number of times of the reciprocating motion of the electromagnetic drive means can be carried out without changing the reciprocating motion stroke of the electromagnetic drive means.

Abstract: A high-pressure hermetic compressor suitable for use in a zero-gravity environment. The compressor includes a solenoid, driven by a power supply, which causes a plunger to reciprocate in an internal space filled with hydraulic fluid. Such motion pressurizes the hydraulic fluid causing a diaphragm to distort. The deformation of the diaphragm compresses fluid in a compression chamber.

Abstract: An electromagnetic reciprocating pump having a piston electromagnetically moved at least in one direction is comprised of a frame having attached thereto an electromagnet which operates the piston, an inner cylinder whose one end side in the axial direction is secured to the frame and the other side thereof is closed and having the piston accommodated therein such that the piston can be reciprocated therein, an outer cylinder whose one end in the axial direction being secured to the frame and coaxially encircling the inner cylinder so as to form a working chamber between it and the inner cylinder, an outer piston accommodated within the working chamber so as to freely reciprocate and varying a capacity of working chamber, spring means being contracted and expanded in accordance with the movement of the outer piston, and magnetic coupling means for magnetically coupling the inner piston and the outer piston.

Abstract: A solenoid-operated reciprocating pump includes a casing having a cylinder with a central axis. A main shaft is disposed in and secured at one end to the casing in alignment with the central axis of the cylinder. A piston having a piston head is slidably fitted over the main shaft such that the piston head is disposed within the cylinder for axial motion. A coil spring extends between the piston and casing to bias the piston in a first axial direction and an armature radially extends from the outer periphery of the piston for interaction with an electromagnet disposed around the longitudinal periphery of the piston. The electromagnet attracts the armature and hence the piston in a second axial direction opposite from the first direction.

Abstract: A pump unit comprises a pump piston driven by a linear electric motor having induction and reaction members with closely adjacent flat surfaces. A reaction member can be sandwiched between two induction members. Co-operating induction and reaction members extend radially from a rod connected to the piston or to two axially spaced pistons or are grouped tangentially around it. The piston or pistons are driven synchronously and so that constant force is applied by way of a control system which includes a trajectory generator and a controller responsive to selected inputs relating to pump performance characteristics and feedback signals derived from measured current flow and piston position.

Abstract: A motor has a plurality of pistons each of which has a ceramic magnet mounted thereon. The ceramic magnets are permanently polarized, and each piston is mounted in a cylinder to reciprocate within that cylinder. An electromagnet is located at each end of each cylinder, and is energized to alternately attract and repel the ceramic magnet so that the piston is caused to reciprocate in the cylinder under the influence of the electromagnets. Hydraulic fluid is drawn into the cylinder and is forced out of that cylinder as the piston reciprocates and this fluid is used to drive a turbine which in turn is used to generate mechanical power.

Abstract: The invention relates to a pressure actuated lift valve in a rotary screw machine mounted in one of the end walls of the machine, e.g. for the purpose of controlling the built-in volume ratio of the machine. The valve contains a cylindrical valve member 11 displaceable in an axial boring 13 and an actuating piston 12 in a cylinder 14. The boring 13 extends between the working space 24 of the machine and said cylinder 14. Through channels 20, 21, 22 pressure fluid is supplied to the cylinder 14 whereby the actuating piston 12 affects the valve member 11 to take an open or a closed position.By making the actuating means as a unit separate from the valve member 11 the manufacture is facilitated.

Abstract: An electromagnetic diaphragm pump, the mounts for positioning and mounting the field cores on the housing and the fitting portions for fitting the peripheral portions of the diaphragms are integrally formed with the housing so that the attaching positions of the field cores never shift after they are attached. Screw holes are formed through the mounts for attaching the field cores to make the attaching and fixing of the field cores easier.

Abstract: A long life, very low friction pump for use in a heat pipe pump or the like is disclosed. A first pump uses magnetically confined ferrofluid rings as both sealer and lubricant for a sliding pump piston in a two sided piston pump that minimizes the seal pressures on both sides of the ferrofluid seals. A second pump uses a magnetically confined ferrofluid slug as a self-sealing and self-repairing pump piston.

Abstract: A magnet holder for an electromagnetic diaphragm pump comprising a reinforcing member having at least in part thereof a width smaller than the distance between a pair of magnets placed in the predetermined positions in magnet insertion windows is provided integrally with the magnet holder between the pair of magnet insertion windows for juxtaposing and holding a pair of flat plate-shaped magnets in the same plane, so that the mechanical strength of the magnet holder is prevented from decreasing. And positioning members may be formed in the reinforcing member for pressing the pair of magnets inserted into the magnet insertion windows toward the diaphragms attached to opposite ends of the magnet holder, thereby positioning the magnets with enough accuracy and determining the distance between the magnets.

Abstract: A vibrator for diaphragm pump and magnet holder for the vibrator wherein a stopper is formed on the inner perimeter of the side wall of the magnet insertion window in the vicinity of one main plane of the magnet holder, and that the supporting surface of the stopper for the magnet is fixed at the distance of 1/2 of the difference between the thicknesses of the magnet holder and the magnet to be inserted into the magnet insertion window, from the one main plane. A plurality of said stoppers are formed partially along the inner periphery of the magnet insertion window. Recesses are formed in appropriate portions of the perimeter of the magnet insertion window, into which the bonding agent is made to flow.

Abstract: A long life, very low friction pump for use in a heat pipe pump or the like s disclosed. A first pump uses magnetically confined ferrofluid rings are both sealer and lubricant for a sliding pump piston in a two sided piston pump that minimizes the seal pressures on both sides of the ferrofluid seals. A second pump uses a magnetically confined ferrofluid slug as a self-sealing and self-repairing pump piston.

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

Abstract: In subsea production of oil and gas, a pressurized fluid is needed for operation of valves for the production system. To be able to supply a hydraulic actuator with pressure medium for valve operation without arranging any pressurization from a platform-based pump, a liquid pump has been produced which is driven by rods of a giant magnetostriction material and which may be connected to operating devices and valves at the bottom of the sea. The liquid pump has a high efficiency and has few movable parts. By utilizing the giant magnetostrictive in two alternately operating rods (11) which are arranged in pairs and are surrounded by coils (15) supplied with current, the first rod imparting a movement when magnetic energy is transformed into mechanical energy in the form of a deformation and the second rod dynamically prestressing the first rod together with a load, a piston (12) in a cylinder space (17) of a pump housing (16) may be caused to oscillate for transporting liquid.

Abstract: An electromagnetic pump comprising fluid operation chambers for discharging fluid to the outside; and electromagnet connected to an AC power source device for polarity switching for every half cycle of AC when energized; a permanent magent which moves together with the electromagnets; and a reciprocative shaft holding the permanent magnet, which reciprocates in the shaft direction when the electromagnet is energized. The width of a securement portion for the permanent magnet of the reciprocative shaft is relatively narrow compared to the other portions, and the permanent magnet consists of a pair of permanent magnet pieces bonded together by sandwiching the securement portion therebetween. The electromagnetic pump further comprises a fluid operation member for expanding or contracting the volume in the fluid operation chamber by the reciprocation movement of the reciprocative shaft so as to guide fluid out.

Abstract: An air pump includes a housing body containing an electromagnetic drive mechanism for oscillating a pair of diaphragms. The diaphragms define variable volume chambers, the chambers communicating with suction and discharge ports for establishing an air flow in response to diaphragm oscillation. The drive mechanism comprises coils defining an air gap and a permanent magnet type actuator reciprocably mounted in the air gap. The top of the housing body is open to enable the actuator to be visually inspected for proper alignment within the air gap. A cover is installed over the open top of the housing body with the actuator properly installed in the air gap. The cover contains air passages communicating with the suction and discharge ports. The weight of the diaphragm can be altered to achieve a desired resonance frequency tuned to the frequency of the electrical current.

Abstract: A three-stage compressor wherein the housing proper has a central bore with two adjacent bores that are co-axial therewith. A first piston is cooperative with the central bore to define a first stage compression chamber. A second piston smaller than the first piston but integral therewith is received by one of the adjacent bores to define a second stage compression chamber that receives its pressurized air from the first chamber. A third piston smaller than the second piston is received by the remaining one of the adjacent bores to define a third stage compression chamber that receives its pressurized air from the second chamber for further compression.

Abstract: In a high pressure pump (1) for liquids or gases with a drive unit (2) and a pair of pump units (3) which are connected by a drive element (4) to a drive shaft driven by a motor (6), a considerable simplification in the sense of large scale production with the lowest possible costs is achieved in that each pump unit (3) exhibits its own closed casing, separate from the drive unit (2), the casing has an inlet (8), an outlet (9), and a tight duct through which a portion of a piston, e.g., at least its piston rod, extends, the piston rods of the pump's pistons are connected to one another by a power transmission element (5) of the drive unit (2), and a solid, inherently stable supporting plate is provided, by way of which at least the casings of the pump units (3) and the drive unit (2) are fixed relative to one another.

Abstract: An electrodynamic motor having a flat plunger core arrangement formed out of alternating layers of magnetic and insulating strips clamped together and maintained on respective bearing sleeves which reciprocate on guide members with the gap between stator members.

Abstract: A free-piston Stirling machine has a piston which can reciprocate and also rotate within a cylinder and which is supported and centered in the cylinder by a grooved dynamic bearing, the piston having two end faces which are acted upon during operation by different fluid pressures. The piston includes at least one sealing part having a circular-cylindrical smooth sealing surfaces and at least one bearing part which is provided in its peripheral surface with a groove pattern. The length of the sealing surface and the size of the gap between the sealing surface and the cylinder wall are selected such that the pressure difference across the bearing surface is reduced so that the piston remains free of radial dynamic instability during operation.

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

Abstract: Pump apparatus (10; 110) for the controlled ingress and egress of a fluid comprising, a generally cylindrical housing (11; 111), flexible septum (55; 155) disposed within the housing and attached to the housing substantially axially medially thereof, an electromagnet assembly (65; 165, 165') affixed to the septum, a pair of inlet ports (25, 25; 125, 125) in the housing with one disposed to either side of the septum, valves (35; 135) in the inlet ports permitting only ingress of fluid to said housing, a pair of outlet ports (26, 26; 126, 126) in the housing with one disposed to either side of the septum, valves (35; 135) in the outlet ports permitting only the egress of fluid from the housing, permanent magnets (45, 46; 145, 146) disposed proximate the axial extremities of the housing, and a controller (70; 170) for selectively energizing the electromagnet assembly for the controlled displacement of the septum axially of the housing to alternately effect the ingress and egress of fluid from the inlet and outle

Abstract: A resonant reciprocating compressor wherein a reciprocating assembly comprising the movable armature of an electric reciprocating motor and a piston means coupled to the armature is driven cyclically when the electric motor is energized from an alternating current source to compress a working fluid, and including means operatively associated with the reciprocating assembly for producing a stabilizing force gradient in a direction to maintain or restore the reciprocating assembly to a centered operating position.

Abstract: A piezoelectric fluid pumping apparatus includes pumping means for supplying a fluid under pressure and an energizer arranged in driving relationship therewith. The energizer includes a generally planar flexure member having first and second piezoelectric laminates supported thereon. The flexure member includes a first edge and a second edge, the edges being resiliently constrained for substantially preventing longitudinal movement thereof when an electrical signal is applied to the laminates. Preferred embodiments of the flexure member include bimorphous, biunimorphous and quadrimorphous piezoelectric structures.

Abstract: A pump is constructed using a magnetic piston in a cylinder having an oil feed thereto, for pumping oil to either pressure chamber of a steering servomotor. The pump cylinder has a chamber on each side of the pump piston which chambers discharge pressure oil into a respective servomotor chamber. The magnetic piston is actuated by an electromagnetic system under control of a manually operated steering wheel. The pump construction is such that the length of traverse of the pump piston on a pressure movement is shorter than the piston traverse of a servomotor chamber being pressurized. The pump chambers discharge directly into respective servomotor chambers without the need for steering control valving.

Abstract: A metering pump including adjacent valve and pump chambers, the valve chamber having inlet and outlet connections and a valve plug angularly shiftable in the valve chamber to communicate said connections with opposite sides of the plug upon angular shifting of the plug, and a reciprocatory piston in the pump chamber, there being fluid communication between opposite ends of the pump chamber and the valve chamber on opposite sides of the valve plug, so that piston reciprocation in both directions moves fluid in the inlet connection and out the outlet connection upon shifting of the valve plug.

Abstract: A magnetic pump having a housing or block with three compartments and a port for supplying fluid into the center compartment. A pair of receivers are mounted in the center compartment and have check valves to allow fluid to flow into the receivers and outlets for conducting fluid out of the receivers. A sliding sleeve is mounted near each receiver and is reciprocal between two positions in which fluid is enclosed on one side of the receiver or the other. A piston assembly, mounted within each sleeve, is reciprocal to force the enclosed fluid from within the sleeve through the check valves into the receiver. The sleeves and the pistons are reciprocated electromagnetically. The cycle of the sleeves slightly preceeds the cycle of the pistons.

Abstract: In a free piston type oscillating compressor, closed spaces separate from gas springs are provided, and pressures of the closed spaces are regulated, whereby the amplitude, and central position of the stroke, of a free piston can be precisely controlled.

Abstract: A marine propulsion system is provided with a valve (2) for automatically mixing fuel and oil for a two cycle crankcase compression internal combustion engine. The valve operates on a pressure differential, such as that supplied from the suction intake vacuum side of a fuel pump. Fuel is alternately and cyclicly directed by a transitioning shuttle spool valve (50) through respective transfer passages (34, 38) to opposite sides of a diaphragm (24) to drive the diaphragm in reciprocal movement such that in a first half cycle the diaphragm is driven in one direction and expels fuel from its one side, and in the second half cycle the diaphragm is driven in the other direction and expels fuel from its other side. A plunger (48) operatively couples the diaphragm to the directional shuttle spool valve through spring biased lost motion detent means (52). The directional shuttle spool valve is actuated between its alternate positions near the end of the plunger travel stroke in each direction.