An amplifier includes a first input terminal, a second input terminal, a TIA, and a compensation circuit. The TIA includes a first transistor, a second transistor, a first current source connected to the first input terminal and an emitter of the first transistor, a second current source connected to the second input terminal and an emitter of the second transistor, a first load resistor connected to a collector of the first transistor, and a second load resistor connected to a collector of the second transistor. A bias voltage is supplied to bases of the first and second transistors, the compensation circuit adjusts a first load current and a second load current based on voltage signals, and the TIA outputs the voltage signals based on collector voltages of the first and second transistors.

Split amplifiers with configurable gain and linearization circuitry are disclosed. In an exemplary design, an apparatus includes first and second amplifier circuits and a linearization circuit, which may be part of an amplifier. The first and second amplifier circuits are coupled in parallel and to an amplifier input. The linearization circuit is also coupled to the amplifier input. The first and second amplifier circuits are enabled in a high-gain mode. One of the first and second amplifier circuits is enabled in a low-gain mode. The linearization circuit is enabled in the second mode and disabled in the first mode. The amplifier is split into multiple sections. Each section includes an amplifier circuit and is a fraction of the amplifier. High linearly may be obtained using one amplifier circuit and the linearization circuit in the low-gain mode.

Embodiments include systems and methods for accurately controlling gain of a high-speed variable-gain amplifier (VGA) without adversely impacting bandwidth performance. Embodiments include a VGA with a variable resistor, for which resistance is a function of a control level. A gain calibration system controls the control level by using a gain control feedback subsystem to sample outputs of a duplicate VGA, which includes a duplicate variable resistor. The sampled duplicate outputs are compared to a target gain generated by a reference generator. The control level can be fed back to control the gain of the duplicate VGA until the target gain is reached. The control level can also be fed to the actual VGA to control its gain. By performing gain control on the duplicate VGA without interfering with the output signal path of the actual VGA, the actual VGA's gain can be accurately controlled without impacting its bandwidth.

Exemplary embodiments are directed to operating a multi-stage amplifier with low-voltage supply voltages. A multi-stage amplifier may include a first path of an amplifier output stage configured to convey an output signal if a first supply voltage is greater than a threshold voltage. The multi-stage amplifier may also include a second path of the amplifier output stage configured to convey the output signal if the first supply voltage is less than or equal to the threshold voltage.

A variable gain amplifier (100) includes a transistor (110), an FB impedance section (120), a source impedance section (130), a drain impedance section (140), a gain controller (150), and a frequency characteristic controller (160). The gain controller (150) varies impedance of one of the FB impedance section (140), the source impedance section (130), and the drain impedance section (140), and outputs a gain control signal. The frequency characteristic controller (160) varies the impedance of different impedance section, based on the gain control signal.

This disclosure relates generally to radio frequency (RF) amplification devices and methods of limiting an RF signal current. Embodiments of the RF amplification device include an RF amplification circuit and a feedback circuit. The RF amplification circuit is configured to amplify an RF input signal so as to generate an amplified RF signal that provides an RF signal current with a current magnitude. The feedback circuit is used to limit the RF signal current. In particular, a thermal sense element in the feedback circuit is configured to generate a sense current, and thermal conduction from the RF amplification circuit sets a sense current level of the sense current as being indicative of the current magnitude of the RF signal current. To limit the RF signal current, the feedback circuit decreases the current magnitude of the RF signal current in response to the sense current level reaching a trigger current level.

A microwave semiconductor amplifier includes a semiconductor amplifier element, an input matching circuit and an output matching circuit. The semiconductor amplifying element includes an input electrode and an output electrode and has a capacitive output impedance. The input matching circuit is connected to the input electrode. The output matching circuit includes a bonding wire and a first transmission line. The bonding wire includes first and second end portions. The first end portion is connected to the output electrode. The second end portion is connected to one end portion of the first transmission line. A fundamental impedance and a second harmonic impedance seen toward the external load change toward the one end portion. The second harmonic impedance at the one end portion has an inductive reactance. The output matching circuit matches the capacitive output impedance of the semiconductor amplifying element to the fundamental impedance of the external load.

A tunable wide band driver amplifier is disclosed. In an exemplary embodiment, an apparatus includes a first band selection circuit selectively connected between an output terminal of an amplifier and a circuit ground. The first band selection circuit configured to adjust an amplification band from a first frequency band to a second frequency band. The apparatus also includes a first harmonic reduction circuit selectively connected between the first band selection circuit and the circuit ground and configured to reduce 2nd harmonic frequencies associated with the first frequency band when the amplification band is set to the first frequency band.

A light emitting apparatus including: a plurality of light emitting elements; a drive circuit including a transistor and a capacitor having one end connected to a gate of the transistor; and a signal supply circuit for receiving a digital gradation signal and outputting an analog voltage signal to the drive circuit, including a computation circuit configured to correct the input digital gradation signal to generate a corrected digital gradation signal, in which the drive circuit is configured to conduct an auto-zero operation which reduce the gate-source voltage of the transistor to a threshold voltage by flowing the drain current to the capacitor, and the computation circuit is configured to generate the corrected digital gradation signal by multiplying a correction coefficient to the input digital gradation signal subtracted by a particular signal common to the plurality of light emitting elements.

An apparatus is described that includes an audio power amplifier having an input and an output. An alternating-current to direct-current power converter is coupled to the audio power amplifier in a single package to supply power to the audio power amplifier.

Disclosed is a technique for reducing noise superimposed on an output signal while keeping loop gain constant without increasing the circuit scale and without changing the transfer function of the amplifier apparatus (frequency characteristics of gain and phase). According to the technique, there are included a power-supply voltage control unit 7 for detecting the amplitude level S9 of an input audio signal S1 and outputting power with a voltage value indicated by target set voltage value information Vs corresponding to this amplitude level S9, and a PWM modulation unit 2 including a PWM converter 23 for converting the pulse width of the input audio signal S1 and a correction unit for correcting the signal modulated by the PWM converter 23. The PWM modulation unit 2 corrects the pulse width of a PWM signal S5 modulated by the PWM converter 23 so that the correction unit will cancel out a change in amplification gain of a power amplification unit 4 according to the target set voltage value information Vs.

A pop-free single-ended output class-D amplifier includes: an input signal generator for generating an input signal; a power supply for supplying input power; a reference voltage generator for generating a reference voltage; a gain-adjustable stage for generating an amplified signal according to the reference voltage and adjusting a gain of the single-ended output class-D amplifier; a pulse width modulation module for outputting a pulse width modulation signal according to the reference voltage, the amplified signal, and the input power; a low-pass filter for low-pass filtering the pulse width modulation signal to generate an output voltage; and a logic controller for generating at least one control signal to control the reference voltage generator, the gain-adjustable stage, and the pulse width modulation module according to the input power, the reference voltage, and the pulse width modulation signal.

An electronic circuit, including, a power amplifier adapted to amplify an RF signal and provide it as output from the integrated circuit; a power source that is adapted to provide an unregulated voltage to the power amplifier; a regulator adapted to provide a regulated bias voltage; a subtracter that is adapted to accept a voltage proportional to the unregulated voltage and subtract it from the bias voltage to provide a reference voltage to the power amplifier; wherein the power amplifier is adapted to use the reference voltage to adjust the output from the power amplifier so that it will provide a stable power output.

Differential amplifier circuits for LDMOS-based amplifiers are disclosed. The differential amplifier circuits comprise a high resistivity substrate and separate DC and AC ground connections. Such amplifier circuits may not require thru-substrate vias for ground connection.

Differential power amplifier circuitry includes a differential transistor pair, an input transformer, and biasing circuitry. The base contact of each transistor in the differential transistor pair may be coupled to the input transformer through a coupling capacitor. The coupling capacitors may be designed to resonate with the input transformer about a desired frequency range, thereby passing desirable signals to the differential transistor pair while blocking undesirable signals. The biasing circuitry may include a pair of emitter follower transistors, each coupled at the emitter to the base contact of each one of the transistors in the differential transistor pair and adapted to bias the differential transistor pair to maximize efficiency and stability.

An amplifier circuit amplifies a signal for wireless transmission. A feedback circuit, including a capacitor, is coupled to the amplifier circuit. Components of the feedback circuit are selected based on a feedback factor such that an input impedance to the amplifier circuit has a same impedance characteristic as a feedback circuit impedance of the feedback circuit.

A semiconductor package device comprises a radio frequency power transistor having an output port operably coupled to a single de-coupling capacitance located within the semiconductor package device. The single de-coupling capacitance is arranged to provide both high frequency decoupling and low frequency decoupling of signals output from the radio frequency power transistor.

A power amplifier module includes a power amplifier including a GaAs bipolar transistor having a collector, a base abutting the collector, and an emitter, the collector having a doping concentration of at least about 3×1016 cm−3 at a junction with the base, the collector also having at least a first grading in which doping concentration increases away from the base; and an RF transmission line driven by the power amplifier, the RF transmission line including a conductive layer and finish plating on the conductive layer, the finish plating including a gold layer, a palladium layer proximate the gold layer, and a diffusion barrier layer proximate the palladium layer, the diffusion barrier layer including nickel and having a thickness that is less than about the skin depth of nickel at 0.9 GHz. Other embodiments of the module are provided along with related methods and components thereof.

A power amplifier includes: first and second bias terminals to which bias voltages are respectively supplied; a first transistor having a first control terminal connected to the first bias terminal, a first terminal that is grounded, and a second terminal; a second transistor having a second control terminal connected to the second bias terminal, a third terminal connected to the second terminal, and a fourth terminal; a capacitor connected between the second control terminal and a grounding point; and a variable resistor connected in series with the capacitor, between the second control terminal and the grounding point.

Systems and methods are provided for generating an amplitude modulation signal to a switchmode power amplifier. A DC to DC switch is configured to receive a DC input voltage and to provide a DC output voltage. A low dropout regulator is configured to provide the amplitude modulation signal according to a modulation control signal received by the low dropout regulator. A control circuit is configured to establish a nominal operating power level for the power amplifier via the amplitude modulation signal and to maintain a minimum voltage difference between the DC output voltage and the low dropout regulator output. A modulator control circuit is configured to provide the modulation control signal to the low dropout regulator. The modulator control circuit provides the transition from a high amplitude to a low amplitude and a transition from the low amplitude to the high amplitude at configurable first and second slopes, respectively.

Apparatus and methods disclosed herein perform gain, clipping, and phase compensation in the presence of I/Q mismatch in quadrature RF receivers. Gain and phase mismatch are exacerbated by differences in clipping between I & Q signals in low resolution ADCs. Signals in the stronger channel arm are clipped differentially more than weaker signals in the other channel arm. Embodiments herein perform clipping operations during iterations of gain mismatch calculations in order to balance clipping between the I and Q channel arms. Gain compensation coefficients are iteratively converged, clipping levels are established, and data flowing through the network is gain and clipping compensated. A compensation phase angle and phase compensation coefficients are then determined from gain and clipping compensated sample data. The resulting phase compensation coefficients are applied to the gain and clipping corrected receiver data to yield a gain, clipping, and phase compensated data stream.

A transceiver includes: a power amplifying circuit arranged to generate differential output signals during a transmitting mode of the transceiver; a balance-unbalance circuit arranged to convert the differential output signals into a single-ended output signal; a switchable matching circuit arranged to receive the single-ended output signal on a signal port of the transceiver during the transmitting mode, and to convert a single-ended receiving signal on the signal port into a single-ended input signal during a receiving mode of the transceiver; and a low-noise amplifying circuit arranged to convert the single-ended input signal into a low-noise input signal during the receiving mode. The power amplifying circuit, the Balun, the switchable matching circuit, and the low-noise amplifying circuit are configured as a single chip.

Systems and methods are provided for amplifying multiple input signals to generate multiple output signals. An example system includes a first channel, a second channel, and a third channel. The first channel is configured to receive one or more first input signals, process information associated with the one or more first input signals and a first ramp signal, and generate one or more first output signals. The second channel is configured to receive one or more second input signals, process information associated with the one or more second input signals and a second ramp signal, and generate one or more second output signals. The first ramp signal corresponds to a first phase. The second ramp signal corresponds to a second phase. The first phase and the second phase are different.

An amplifier includes a signal processing circuit configured to generate an orthogonal signal orthogonal to an input signal; a first D/A converter configured to convert the orthogonal signal into a first analog signal; a second D/A converter configured to convert the input signal into a second analog signal; and an analog computing circuit configured to generate a constant envelope signal based on the first analog signal from the first D/A converter and the second analog signal from the second D/A converter.

An apparatus for amplifying power is provided. The apparatus includes a supply modulator for generating a supply voltage based on an amplitude component of a transmission signal, and a power amplify module for amplifying power of the transmission signal using the supply voltage, wherein the power amplify module includes a first power amplifier and a second power amplifier, and when an output power of the transmission signal is greater than a reference power, the first power amplifier amplifies the power of the transmission signal using the supply voltage, and when the output power of the transmission signal is equal to or less than the reference power, the second power amplifier amplifies the power of the transmission signal using the supply voltage.

A damping tool holder, such as a boring head, a chuck, or a milling cutting arbor, integrates a damping device (2), in the form of an elongated body. The damping device (2) is housed in a mounting body (3), connected by one end to the tool-holder body (1) and having at its other end an end fitting (4) for mounting a tool, whereby the mounting body (3) is equipped with at least one lubricant feed pipe (32), emptying at its front end into the end fitting (4) for mounting a tool and connected at its other end to a circular groove (102) for distributing lubricant that is provided on the front surface of the tool holder (1).

A surgical milling cutter includes a milling cutter bracket, a locking device and a bottom electric motor connected successively. The milling cutter bracket includes a fixing seat with a through hole. A finger guide apparatus with an L-type first bracket at the top end thereof is provided on the upper part of the fixing seat. The end of the L-type first bracket's short side is provided with a downward projection. The lowest point of the projection is lower than that of the milling cutter's cylindrical head when the milling cutter is working normally. The surgical milling cutter utilizes the projection to prevent the possibility of an object contacting with the cylindrical head, thus avoiding an object being cut unevenly. Meanwhile, the L-type bracket can be driven by the finger guide apparatus to rotate so as to change the running direction of the milling cutter, thus facilitating surgical procedures.

An internal adapter for use in torque-limiting handles for interchangeable orthopedic tools contains a slidable collar component, house component, retaining ring, spring, driver component, cover and cam which engages a torque-limiting mechanism. A plurality of securing ball mechanisms releasably secure an orthopedic tool in the adapter, while a configuration of chamfered surfaces centrally stabilize the tool. A plurality of guiding chamfers located in a driver component rotationally secures the orthopedic tool.

A holding jig (1, 2, 3) for a thin cylindrical work (W) includes a holding member (10, 10A, 10B) which holds the work (W) from an inner peripheral side and a diameter changing unit (25, 27) which changes a diameter of the holding member (10, 10A, 10B). The holding member (10, 10A, 10B) is made of metal and has a cylindrical shape and an elastically expandable or contractible diameter. The holding member (10, 10A, 10B) is configured with an outside diameter of the holding member (10, 10A, 10B) being held smaller than an inside diameter of the work (W) at the time of insertion into an inner periphery of the work (W) and being expanded after inserted into the inner periphery of the work (W) to hold the work (W) from an inner peripheral side of the work (W) with an outer peripheral surface in close contact with an entire inner peripheral surface of the work (W). The diameter changing unit (25, 27) applies at least one of an axial external force in a compressing direction or an axial external force in a tensile direction to both ends of the holding member (10. 10A, 10B) to change the diameter of the holding member (10, 10A, 10B).

Device for cooling a rotating tool mounted on a machine, including elements for generating a continually renewed first flow of air, external to the tool and around the tool, at a high flow rate, produced via a Coanda-effect flow amplifier device realized in a housing fixed on the machine around the tool holder connected to a source of pressurized air.

A machine and method for knurling an end portion of a cylindrical workpiece including a hypodermic needle or biopsy needle. The machine includes a base to which a reciprocating mechanism and a serrated block are attached. A pressure bar is positioned above the base and has a second serrated block attached thereto. The pressure bar is reciprocated back and forth, each movement comprising a stroke. A pair of lobes are attached to the top surface of the pressure bar. A pair of roller blocks are also attached to the base, each roller block having a rectangular opening and a roller located therein. The pressure bar passes through the rectangular openings. As the pressure bar is reciprocated back and forth and the lobes come into contact with the rollers, the pressure bar is biased toward the base whereby a knurl is formed in a workpiece placed between the two serrated blocks. A method for knurling an end portion of a cylindrical workpiece is also disclosed.

A method and an apparatus is disclosed for forming a one-piece introducer needle having a member portion and a needle portion by introducing a photoresist on a substrate. The temperature of the substrate is increased and then decreased. A photomask is deposited onto a substrate.

A method of stress relieving drilled surgical needles is disclosed. At least the metal about a drilled bore hole is heat treated to relieve stress without annealing.

A radial piston pump has a plurality of cylinders within which pistons reciprocally move. Each cylinder is connected to a first port by an inlet passage that has an inlet check valve, and is connected to a second port by an outlet passage that has an outlet check valve. A throttling plate extends across the inlet passages and has a separate aperture associated with each inlet passage. Rotation of the throttling plate varies the degree of alignment of each aperture with the associated inlet passage, thereby forming variable orifices for altering displacement of the pump. Uniquely shaped apertures specifically affect the rate at which the variable orifices close with throttle plate movement, so that the closure rate decreases with increased closure of the variable orifices.

A liquid flow rate control valve is provided in which since a total area of overlapping sections of a communication hole group (38c, 38d) of a distributor (38) and an outlet opening (37a, 37b) of a sleeve (37) changes when the distributor (38) is rotated by a first electric motor (46), if a rotor (42) is rotated by means of a second electric motor (47), an input port (31e) communicates with an output port (31f) through an inlet opening (42c, 42d) of the rotor (42), the communication hole group (38c, 38d) of the distributor (38), and the outlet opening (37a, 37b) of the sleeve (37) when the inlet opening (42c, 42d) of the rotor (42) passes through the overlapping sections, thereby making it possible to carry out PWM control of a flow rate of liquid. Since a thrust load in an axis (L) direction does not act on the distributor (38) and the rotor (42), supporting the distributor (38) and the rotor (42) becomes easy, thereby enabling the cost and weight to be cut.

The present invention relates to an implement, in particular an excavator or machine for material handling, with an element movable via at least one working drive, wherein at least one energy recovery cylinder is provided for energy recovery from the movement of the movable element, which includes a chamber filled with gas, wherein the actuation of the implement is effected in dependence on the directly or indirectly determined temperature of the gas in the chamber filled with gas.

Method of indicating the position of a hydraulically actuated armature, comprising an adjust cylinder for actuating the armature, connected by at least one pressure medium line to an adjustment valve through which the pressure medium line can be switched between pressure-causing forward flow and pressure-less backward flow, wherein the flow through the pressure medium line is converted into a number of electric pulses and the number of pulses reflecting the flow is processed in a program in an indicator unit such that the number of pulses occurring in a predetermined adjustment travel when the flow in the pressure medium line is pressure-less is calculated as being the same adjustment travel as when the pressure medium line is switched to be the pressure line.

The invention relates to a method for constructing a gas-filled double-acting hydraulic cylinder (1) with gas spring action, comprising: —a cylinder sleeve (3) with a cylinder bottom (3a) and cylinder head (3b) —a piston/piston rod assembly (5) a hydraulic fluid seal on the piston (9) —a connection for the head-side chamber (13) to a hydraulic line; —a connection for the bottom-side chamber (15) to a hydraulic line, —a gland (20) with a bore, the gland being attached between the cylinder bottom (3a) and the piston (9), the piston rod (7) extending over the entire stroke of the piston rod through the bore, wherein the gland comprises two seals —(25), one for providing a seal with the cylinder sleeve (3) and one for providing a seal with the piston rod.

A system comprises a first piston comprising a first piston shaft and a first drive pin. A first piston cylinder comprises a first body and a first groove, wherein the first groove defines a first aperture, the first aperture oriented axially along the first body and configured to receive the first drive pin. The first body encloses the first piston and allows the first piston to travel axially within the first piston cylinder. A drive shaft comprises an axis, a drive groove, and a surface, wherein the drive groove forms a continuous channel along the surface and receives the first drive pin. In one embodiment, a first distribution wheel comprises a first face, a second face, a first inlet aperture, and a first outlet aperture. The first distribution wheel couples to the first piston cylinder and to the drive shaft at a first end of the drive shaft, and rotates axially with the drive shaft along the axis of the drive shaft. The first inlet aperture allows hydraulic fluid to pass through the first face and the second face and the first outlet aperture defines a groove on the second face.

The invention relates to a neutral setting apparatus for adjustable hydraulic machines, in particular the adjustment of the neutral position of a servo valve. In particular, the invention relates to servo adjustment devices with mechanically adjustable control pistons, wherein the forces necessary for this can be applied mechanically, electro-magnetically, pneumatically or hydraulically. The invention relates to a neutral setting apparatus of an adjustable hydraulic machine, with a housing in which a mounted input shaft is arranged, to one end of which a torque can be applied for rotating the input shaft about an axis. Thus providing a robust and cost-effective setting mechanism for the neutral position of a servo valve.

The disclosed invention introduces an efficient lifting mechanism for reciprocating vertically a load system, the load consisting of the aggregate weights of a cargo payload in conjunction with “dead weights” of moving parts of the lifting apparatus. The disclosed invention uses a hydro-pneumatic linear actuator to lift the load and a pressurized accumulator, acting as a force intensifier. The pressurized accumulator, acting as a self-contained stored energy source, provides to the actuator adequate power to lift the “dead weights” plus part of the cargo payload. An external power source provides to the actuator adequate power to lift the remainder of the cargo payload. The disclosed invention saves significant amounts of power and energy in applications in which the “dead weights” are sizable compared to the cargo load. The disclosed invention provides also exceptional means for accurate motion control of the cargo payload.

A method and apparatus for a fluid damper comprising a first fluid-filled chamber, a second chamber filled with a fluid having variable flow characteristics and at least partially displaceable by the first fluid, and a gas chamber, the gas chamber compressible due to the displacement of the second chamber. In one embodiment, the fluid in the second chamber is a variable rheology fluid.

The present invention relates to devices and systems that alter intracranial compliance, cerebral blood flow and/or intracranial pressure pulsatility/waveform by oscillating the contraction and expansion of a compressible composition within the cranial or spinal cavities such that they increase intracranial capacity. The contraction and expansion of the compressible composition in the oscillating compliance devices can be due to an individual's intracranial pressure, the result of the expansion and compression of a reservoir which is mediated by the contractility of the heart or driven by a pump gaited to a biorhythm. The invention also relates to methods for protecting an individual's brain from abnormal arterial pulsations and for altering an individual's cerebral blood flow using the devices and systems of the invention. The oscillating compliance devices can be used to treat several diseases and/or conditions characterized by altered/abnormal intracranial compliance, cerebral blood flow and/or intracranial pressure pulsatility/waveform, including hydrocephalus, stroke, dementia and migraine headaches, vasospasms, congestive heart failure, cardiopulmonary bypass or carotid endarterectomy.

A sensor coupler adapted to operatively connect a sensor to a piston-cylinder assembly. The sensor coupler includes a first end member and a second end member. The first end member is disposed on a port of the piston-cylinder assembly, in communication with the sensor, and the second end member is disposed in a cylinder chamber of the piston-cylinder assembly. Further, one or more cables are extending between the first end member and the second end member. The one or more cables are configured to transmit signals indicative of a position of a piston in the piston-cylinder assembly to the sensor. The sensor coupler further includes a biasing member to connect the first end member and the second end member.

A hydraulic control system is disclosed for use with a machine. The hydraulic control system may have a pump, a tank, and an actuator. The hydraulic control system may also have at least a first valve configured to control fluid flow between the pump, the tank, a first chamber of the actuator, and a second chamber of the actuator; a second valve fluidly disposed between the second chamber and the tank; and a third valve fluidly disposed between the first and second chambers. The hydraulic control system may further have a controller configured to selectively cause the second valve to block fluid flow from the second chamber of the actuator to the tank, and to selectively cause the third valve to fluidly communicate the first and second chambers of the actuator when the second valve blocks fluid flow from the second chamber of the actuator to the tank.

A hydraulic feed-rate control apparatus pushes out a fluid by a main piston to a reservoir chamber via feed-rate adjustment mechanisms and flow passages and adjusts a feed rate of a reciprocating body; the adjustment mechanisms comprises first and second throttle valves arranged at front ends of a cylinder and adjusting flow rates of the fluid flowing into the flow passages; the main piston comprises an auxiliary piston integrally moving, and opening and closing the second throttle valve; and the auxiliary piston comprises an outer peripheral portion fitted in the second throttle valve and closed, a concave portion formed between a front portion and rear portion of the outer peripheral portion, a circulation hole formed in an inner peripheral portion of the auxiliary piston, rear-portion escape holes communicating the rear portion and the circulation hole, and concave-portion escape holes communicating the concave portion with the circulation hole.

A manual release valve is provided for a electro-hydraulic actuator of the type including a piston movable in a cylinder and defining a piston side chamber and a rod side chamber, the valve threadedly attached to the housing of the actuator and extending at least partially within the fluid housing conduits, the valve moveable from a closed position fully seated in the housing to an open position for fluidly connecting both the piston side chamber and the rod side chamber to the reservoir, the valve further including a pressure relief portion that is operable when the valve is in the closed position for relieving pressure from at least one of the piston side chamber or the rod side chamber.

This disclosure provides for pressure limiting a hydraulic system to a desired pressure value by a particular circuit by controlling and closing the compensator when the desired pressure setting is achieved. Closing the compensator will reduced the pressure head and flow in the circuit resulting in improved efficiency. One illustrated embodiment of the disclosure provides a relief valve in the pilot signal for a compensator. The method relates to limiting the pressure on an open side of the compensator, such that the pressure on the other side closes the compensator thereby limiting the pressure and also flow in the hydraulic circuit. In other words, the pressure on the open side is limited by the relief valve. Thus, the pressure on the other side increases thereby regulating the flow and pressure through the compensator. In another embodiment of the disclosure, instead of reducing the pressure on the open side, the pressure on the closed side is increased, thereby controlling the flow and pressure of the hydraulic circuit. The pressure can be increased by a pump or any other suitable mode.

A hydraulic motor assembly capable of precise control having a housing, a hydraulic mounting surface located in the housing, a cylinder block rotatably disposed on the hydraulic mounting surface, a motor shaft engaged to the cylinder block and supported proximate to a first end, a plurality of cooperating gears located in the housing and rotationally engaged to a second end of the motor shaft, an output shaft rotationally engaged to the plurality of cooperating gears, a speed sensor located proximate to one of the plurality of cooperating gears, wherein the speed sensor transmits a signal indicative of the rotational speed of the one of the plurality of cooperating gears.

In a reciprocating piston compressor with delivery rate control, the electromagnetic actuating device (3) of the valve lifter (2) has a separate positioning drive (10) for adjusting the working stroke range of the magnetic actuator (5) used, whereby this can be chosen to be small and highly dynamic and only low power losses occur.