Abstract: A piezo-electrically actuated fluid control valve has a nozzle type seat, a magnet opposite from the seat, and a piezoelectric actuator in sheet form between the seat and magnet. The actuator includes a piezo-ceramic layer laminated to an electrode sheet, so that the composite is parallel to the seat and a surface of the magnet. The electrode sheet has opposite edges which extend beyond the piezo-ceramic layer and are clamped by the housing of the valve so that the center of the actuator is positioned between the seat and magnet. When an electric field is applied to the piezo-ceramic layer, the actuator bows or dishes so as to displace from the seat toward the magnet, and the magnetic field of the magnet draws the actuator further away from the seat, to increase the valve opening between the actuator and the seat.

Abstract: The spool of a fluid pressure control valve has an axial through-bore of a larger diameter at one end and a smaller diameter at the opposite end. A larger diameter pin is slidably received in the larger diameter end of the bore and a smaller diameter pin is slidably received in the smaller diameter end of the bore, and the pins are biased apart by a compression spring so as to be in abutment with the housing at both ends of the spool. Pressure from the outlet port is admitted into the through-bore of the spool between the pins so as to produce a feedback pressure force on the spool which is proportional to the value of the outlet pressure and the difference in area between the two pins.

Abstract: The invention relates to a hydraulic pumping unit for feeding the hydraulic tilting cylinder(s) of a vehicle having a tilting cab, having a housing (1), a displacement body mounted for movement in a pumping chamber within the housing (1), a control valve having a bore in connection with the pumping chamber and a control valve body (2) within the bore, the control valve body (2) being provided, at an end (3) projecting beyond said housing (1), with a handle by means of which the control valve body (2) may be turned between at least two positions operative to tilt the cab from the drive position and to tilt the cab back into the drive position of the vehicle respectively. In accordance with the invention, the handle has an inner part (A) that is fixedly connected with the control valve body, and an outer part (B) which encloses the inner part (A) in a free rotating manner and is mounted to be coupled with the inner part by means of a key-operated lock cylinder (24), the outer part (B) forming the handle.

Abstract: A hydraulic coupler has two halves connected together and identical bores in the halves which together promote laminar flow through the coupler. After entering the poppet in one half, flow through the coupler is directed to an enlarged flow section, through the central portion of the coupler to the enlarged flow section in the other half and then through crossbores in the poppet in the other half and out through that poppet. The flow section of each half is between a seating section and an outward section, and the seating section has a cylindrical portion with a diameter which is equal to the diameter of the outward section.

Abstract: A variable assist power steering system for a motor vehicle has an electronically controlled working pressure valve which normally maintains a working pressure at a relief pressure but increases it in response to steering of the vehicle and according to vehicle status, such as vehicle speed. The system also has electronically controlled direction control valves which are actuated to selectively reduce the working pressure to one side or the other of the steering gear piston so as to match a measured handwheel torque with a value which is desired for the vehicle status.

Abstract: Pump assembly, comprising a radial plunger pump for hydraulic fluid, having a pump housing with radial cylinders formed therein, in each of which cylinders a plunger is reciprocable by means of an eccentric rotor, an electric motor with a rotary output shaft which is connected for driving purposes to the rotor of the radial plunger pump, and a reservoir body for forming a reservoir for hydraulic fluid, the radial plunger pump, the electric motor and the reservoir body being interconnected to form a unit. The reservoir body and the electric motor are fitted at the same side of the pump housing, the reservoir body being adjacent to the pump housing at one side and at the opposite side having a recess. The electric motor preferably projects over a part of its length into the recess of the reservoir body. The reservoir body is preferably designed for fixing the pump assembly to a support.

Abstract: An electro-magnetically operated bidirectional two-way air valve capable of changing state at high pressure differentials or high flow rates in either direction has a body which defines a main bore in which an armature is slidably received. The body has a first port and a second port with a seat between them formed at the end of the main bore and a plastic valve element is secured to a neck portion of the armature to seat against the seat when the valve is closed. Frusto-conical surfaces are formed on the valve element and on the neck portion and a transversely extending pin across the main bore retains the armature in the main bore. In a second embodiment, an end of the armature tapers so as to reduce drag, a powder metal flow restrictor is provided in an axial bore in the armature to reduce shift speed and an elastomer bumper is provided to reduce operating noise.

Abstract: A double latching hydraulic valve of the type that either stays open or stays closed at high pressures and only changes state (between open or closed) at low pressures has three ports, with a main valve between the first and second ports which is opened or closed by a poppet. The first port is always in communication with a pressure chamber which biases the poppet against the main valve seat, and the pressure chamber is placed in communication with the third port, which can be connected to tank pressure, only in the open position of the poppet. Thus, a high pressure is provided in the pressure chamber to keep the poppet closed at high pressures, and a low pressure is provided in the pressure chamber to keep the poppet open at high pressures, without excessive leakage through the valve when it is closed.

Abstract: A proportional pressure control valve has a poppet including a control pin for seating against the seat and which is pressed into a generally tubular armature. One end of the armature proximal to the seat has an enlarged diameter and fits into a cup shaped recess of the housing in an extreme position of the poppet. A smaller diameter of the armature is journaled in a magnetic sleeve bearing at a distal end of the poppet and the control pin is journaled in a sleeve bearing at the proximal end of the popper. A plastic plug covers the distal end of the armature and an annular gap is created at the distal end of the armature bearing between the armature and the housing.

Abstract: The magnetic interface between the housing and armature of a poppet type electromagnetically actuated fluid control valve creates a magnetic flux path through opposing axially and radially facing surfaces of the housing and armature to reduce the pull-in voltage of the valve at large axial gaps between the armature and housing.

Abstract: A high efficiency heat transfer system includes a power circuit (350) and heat pump circuit (352). Each circuit having a working fluid flowing therein. In the power circuit, a heater (354) vaporizes the working fluid which is periodically delivered and exhausted through a valve assembly (358) to a power unit (362). The power unit is also a compressor for the working fluid in the heat pump circuit. Fluid exhausted from the driven section of the power unit is passed to a four-way valve (406) which selectively delivers the working fluid to an interior coil (416) or an exterior coil (408) to heat or cool an area. In extremely cold ambient temperatures, the area is heated directly from the power circuit using a by-pass exchanger (428).

Abstract: A radial piston pump of the type, in which an excentric rotor (7) is adapted to cause the pistons (4) to perform a reciprocating movement within radial cylinders (3) in the pump body (1), the radial inner ends of the pistons (4) being each provided with a broadened foot (6), said broadened feet (65) being kept in contact with the rotor (7) also during the suction strokes of the respective pistons (4) by means of a coupling ring (26) of a substantially L-shaped cross section, the axial ring portion (26a) of which engages the radial outer end faces of the broadened feet (6) and the radial portion (26b) of which keeps said ring (26) axially in place.

Abstract: Disclosed is a process for growing living cellular material in a reaction zone having a membrane in contact with an aqueous medium. The concentration of nutrient in samples from the process is measured using a spectrometric instrument to obtain spectral data characteristic of nutrient components. This spectral data is analyzed using a chi-squared mathematical technique to determine the unknown concentration of nutrient components in said samples. Then the rate at which nutrient is fed to the reaction zone is altered based on the determination of concentration of nutrient components as required to optimize the process.

Abstract: A pump having a reciprocating piston/plunger unit adapted to be actuated by a railway wheel rolling over it has a unitary plunger and piston, with the piston double-acting so that when the outlet pressure exceeds a certain value, the plunger remains retracted. An accumulator is provided in fluid communication with the outlet so as to store accumulated hydraulic pressure.

Abstract: A liquid tank cap incorporates a two-way relief valve in which an annular valve disc has one side sealed against a seal adjacent to its inner diameter and the other side sealed against a seal adjacent to its outside diameter. When subjected to a pressure differential in either direction, the disc deflects so as to increase its concavity and allow air passage by one or the other seal, depending upon whether the pressure in the tank is subatmospheric or superatmospheric.

Abstract: A caster has a stationary hub with a bearing between the hub and a floor engaging wheel ring which allows the wheel ring to rotate relative to the hub. Torsional elastomeric elements mount the hub between spaced support arms radially inward of the bearing and are positioned eccentrically relative to the axis of rotation of the wheel ring so as to suspend the hub resiliently between the arms. In an alternate embodiment, the hub is cantilevered from a single support arm.

Abstract: A self-contained rotary actuator assembly has a pump assembly, a precharged hydraulic circuit, and a rotary vane actuator in a single unit. The pump assembly is a bi-directional electric motor driven gerotor pump which is manifolded to a module assembly in which the control elements of the hydraulic circuit are housed. Upon the application of the pressure for driving the rotary actuator in either direction, a pilot operated hydraulic valve is shifted so as to communicate the rotary actuator with the pump. After the pump is turned off, an orifice for the pilot chamber of the valve bleeds the pilot chamber slowly so as to provide a delay in which the rotary actuator holds the convertible top extended or retracted to give the vehicle operator time to latch the top in its closed or open position. In addition, a gas charged precharge chamber in the hydraulic circuit maintains a precharge through a broad range of temperatures.

Abstract: A hydraulic fluid reservoir contains an extensible bladder which has its exterior exposed to the fluid and its interior vented to the exterior of the reservoir. The interior of the bladder is sealed from the hydraulic fluid in the reservoir. Depletion of the fluid from the reservoir results in distension of the bladder and replenishing the fluid to the reservoir collapses the bladder. The bladder is pleated and a tie-rod which holds the reservoir together extends through the bladder.

Abstract: A two stage pump has coaxial first and second stage reciprocating pumps with the second stage piston reciprocably driven by the first stage piston. Multiple sets of first and second stage pumps are provided, and the second stage pistons can be returned by supercharge pressure, a loose connection between the first and second stage pistons, or a spring. An accumulator which is charged on a compression stroke and discharged on an intake stroke may also be provided in communication with a pumping chamber to improve the efficiency of a pump.

Abstract: A hydraulic circuit comprising at least two double acting hydraulic piston-cylinder devices, for opening and closing a folding roof of a vehicle, with both ends of each piston-cylinder device each connected to a conduit supplied with pressurized fluid by a common hydraulic pump and to a return conduit leading to a source of hydraulic fluid, via 3/2 electrically activated valves. The 3/2 valves include a main ball (22) and seat (22a), with a check valve (32) of the ball seat type upstream of the main ball seat in a connection to the conduit supplied with pressurized fluid.