Abstract: The invention relates to a hydraulic shock absorber with two-way action, in which two pistons (18, 19), one for each direction of motion, act in a housing (1). The pistons (18, 19) are movable relative to each other in, or with, a pressure tube (6). Equalizing elements (4, 5) are provided at the ends. The pistons (18, 19) are each provided with a piston rod. The piston rods are provided with seals (38, 39) which are nearly completely relieved of pressure.

Abstract: A sealing structure to couple an irrigation valve through a rectangular opening in the side of a pipe includes a rectangular conduit portion and a rectangular gasket of elastomeric material. The gasket has a side wall which is wider than the other walls and flange portions which extend outwardly against the inner and outer surfaces of the pipe around the rectangular opening. The conduit includes a laterally extending flange which, upon assembly, encompasses the wider wall. Compression of the wider wall permits insertion of the other side of the conduit through the central opening in the gasket, forming a watertight seal with the rectangular opening.

Abstract: A microprocessor control system includes a bit/byte memory array to enhance the performance characteristics of a microprocessor. The bit/byte memory array selectively allows the microprocessor to manipulate individual bits in the memory thereby reducing both execution time and program size. In addition, the bit/byte memory array allows the microprocessor to address data bytes in the memory array to quickly enable the transferring of large amounts of data.

Abstract: A circuit for monitoring the load current supplied by an uninterruptable power supply for transferring the load to a secondary source when the load current exceeds the capability of the uninterruptable power system. A signal representing the load current is simultaneously, continuously compared to a first reference level and a second reference level. The second reference level has a greater effective magnitude than the first reference level and whenever it is exceeded by the instantaneous signal the transfer is initiated. The transfer is also initiated whenever the signal uninterruptably exceeds the first reference level for a selected period of time.

Abstract: The invention contemplates a quick-opening valve for release of pressurized gas to suppress a hydrocarbon or the like fire and/or explosion. A piston or poppet-valve member is retained by mechanical-latch mechanism in its readiness condition, normally closing off pressurized liquified suppressant gas against release for fast discharge via a discharge port. Latch release is via short low-friction, low-inertia direct action which is independent of the pressure differential across the valve member.

Abstract: A helicopter weight measuring system for detecting the loaded weight of a helicopter operating under partial or full hover conditions while the wheels of the helicopter are contacting the ground includes means for sensing loading on the landing gear of the helicopter and means for determining the lift produced by a rotating wing of the helicopter. The sensed loading on the landing gear is added to the calculated lift to produce an indication of total helicopter loading.

Abstract: An arc welding control system wherein the welding current is held to a very low value during the time a welding electrode is coupled with a workpiece. When the welding electrode is disengaged from the workpiece, a very low current pilot arc is established. Then, arc voltage monitors effect, first, an increase in the current of the pilot arc and then the closing of a welding current contactor. Both shielded metal arc welding and gas tungsten arc welding modes are accommodated; and, in the latter, when a too low arc voltage condition is detected, arc voltage monitors effect the opening of the welding current contactor for such time as the too low arc voltage condition exists. While the welding current contactor is open, a low current pilot arc is maintained until the too low arc voltage condition is corrected.

Abstract: A hollow probe which is adapted to respond to the degree to which a pipe is filled with fluid includes the use of a tubular conductive probe measuring electrode and a pair of tubular conductive guard electrodes axially displaced from the probe electrode. The tubular electrodes are hollow and are adapted to form a fluid conducting portion of the fluid-carrying pipe. The probe electrode and guard electrodes are separated by solid insulation. The guard electrodes are separated from sections of the pipe on either side of the hollow probe by solid insulation. The guard electrodes are exposed to the contents of the pipe and, by driving the guard electrodes at substantially the same potential as the probe electrode, the adverse effects of a coating of fluid adhering to the probe are substantially eliminated.

Abstract: In order to reduce nuisance warnings and to increase the effectiveness of real warnings produced by a ground proximity warning system, the criteria for generating a warning is varied for certain airport areas to take into account the terrain in those areas. Along with position data, certain flight parameters such as heading, altitude, glideslope and localizer deviation are checked by the system in order to ensure that the aircraft is located in the desired warning modification area. In addition, the ground proximity warning system includes a mechanism for ensuring that the corrected barometric altitude of the aircraft is within acceptable limits.

Abstract: Compact centrifugal fan and filter assemblies for use in providing laminar flow clean air to a work space environment such as those within clean rooms and clean air work stations or cabinets wherein the fan and filter element are mounted in a close physical relationship with respect to one another and within a common plenum chamber and wherein the fan creates an airflow which is initially generally parallel with respect to the filter element and which is thereafter channeled by baffle members so as to provide uniform air pressure and airflow across the filter element while reducing vibration and increasing the air flow rate from the fan and filter assemblies to such clean air environments.

Abstract: A transducer assembly includes first and second stators which are axially aligned with, and bear upon opposite sides of a proof mass. The stators and proof mass are clamped together by means of a sleeve having a side portion with spaced apart upper and lower flanges extending therefrom. The flanges bear against receiving surfaces on the stators with the sleeve under elastic deformation such that a compression force tending to reduce the spacing between the flanges is transmitted to the stators and proof mass as a controlled compressive axial preload.

Abstract: A transducer assembly includes first and second stators which are axially aligned with, and bear upon opposite sides of a proof mass. The stators and proof mass are clamped together by means of a sleeve having a side portion with upper and lower flanges projecting therefrom. An inner sleeve element, formed from a material having a different coefficient of thermal expansion than the side portion, is disposed between the flanges. The temperature of the sleeve is controlled such that the inner sleeve element produces a tensile stress on said flanges, increasing the spacing therebetween. The flanges are then joined to the stators. Thereafter, the temperature of the sleeve is controlled such that the tensile stress produced by the inner sleeve element on the flanges is reduced producing a compression force tending to reduce the flange spacing. This compression force is transmitted to the stators and proof mass as a controlled compressive axial preload.

Abstract: A machine forms tortillas into cooked taco shells using a conveyor with a plurality of complementary, vertically extending forming elements which shift from a nested to an open condition as the conveyor sprockets are traversed for feeding and discharging the product. On the lower conveyor run the forming elements pass through a channel of cooking oil and then on to a station where cooked taco shells are discharged. A loading conveyor feeds tortillas in a spaced column towards the forming elements and an acceleration conveyor operates between the loading conveyor and forming conveyor for positioning the tortilla for engagement with a forming element.

Abstract: A warning system for providing an aural warning to the pilot of a rotary wing aircraft monitors the altitude above ground and barometric descent rate of the aircraft and generates the warning if the descent rate of the aircraft is excessive for the altitude at which the aircraft is flying. The system provides two distinct warnings, one being an early warning advising the pilot of a hazardous condition, and the other being a warning alerting the pilot of imminent danger. The system also includes tactical and non-tactical modes of operation, wherein the warning criteria are adjusted to meet tactical and non-tactical flight conditions.

Abstract: A dynamic low tire pressure detection system for detecting the presence of a low tire mounted on a structural member of an aircraft, such as a bogie beam or nose axle, includes a pair of inclinometers mounted on the structural member and adapted to sense the bend therein. The signals from the inclinometers are combined to generate signals representing the weight carried by the structural member. When the aircraft is moving, the weight signal is analyzed to determine whether particular frequency components are present therein. The amplitude of these frequency components are modified by a gain factor dependent upon a reference amplitude and are added to develop a tire pressure signal. The tire pressure signal is compared against a trip setting to determine whether the tire pressure is within acceptable limits. If the tire pressure is outside of the range of acceptable tire pressures, a signal is generated to warn of a potentially dangerous condition to the aircraft operating personnel.

Abstract: A rotor valve has a set of sealing members or inserts positioned in longitudinal channels formed on the outer surface of a cylindrical rotor. A resilient O-ring snuggly engaged in a groove in the rear surface of each insert urges it against a surrounding rotor chamber formed in a valve body. Due to the resilience of the O-ring, the fluid seal between the rotor and the rotor chamber does not bind due to contaminants or extreme variations in temperature. The sealing inserts are formed of a deformable material. Fluid pressure acting on the inserts deforms them to produce a lateral squeezing force on the O-ring. The interaction between the inserts and the O-ring enhances the integrity of both the seal between the inserts and the surrounding rotor chamber and the seal established by the O-ring itself between the rotor and the insert.

Abstract: A valve is mountable in an opening in a gated pipe to control water flow, particularly in a cablegation system. A gasket is mountable in the irrigation pipe opening and a hollow leg of a T-shaped valve housing is inserted into the mounting member. The housing has a hollow, open-ended tubular portion which receives a hollow valve member. The valve member has an enlarged cap and a side opening alignable with the housing leg, the degree of alignment controlling the amount of flow. The valve member can also include a check valve.

Abstract: In order to improve the accuracy of borehole survey systems utilizing probes with inertial components including inclinometers, two ring laser gyro units are included to provide rotation information to the system. When the probe is moving in a borehole, inclinometer iformation is used to produce a synthetic rotation signal to take the piece of a third gyro and the earth's rotation is used for a similar purpose in combination with signals from the two ring laser gyros when the probe is stopped. Wire line velocity is used in combination with the inclinometer and gyro information to provide signals representing the probe velocity and position. Coordinate transformations are provided in the probe to transform the inertial signals and wire line velocity signals into earth reference coordinate system. Kalman filtering incorporates noninertial velocity data to reduce the effect of errors inherent in the generation of various input signals to the system.

Abstract: An apparatus and method for counting the number of cycles of a sensor signal and of a reference signal that occur during respective time intervals associated with a sampling interval defined by a sample signal. Sensor and reference gate signals are produced and respectively define sensor and reference intervals. The sensor interval begins and ends synchronously with respect to the sensor signal, and the reference interval begins and ends synchronously with respect to the reference signal. The sensor, reference and sampling intervals are approximately coextensive with one another. Cycles of the sensor and reference signals are counted during the sensor and reference intervals, respectively. The process may be repeated for a plurality of successive sampling intervals.

Abstract: A conveyor belt cleaner having at least one blade mounted on a blade carrying member for scraping an endless conveyor belt. The blade carrying member substantially encloses and is telescopically received on a vertically adjustable elongate support member. A plurality of rollers are located between the blade carrying member and support member for rolling the blade carrying member on and off the support member to service the conveyor belt cleaner. An adjustment mechanism is provided for shifting the support member to change the amount of pressure with which the blade engages the endless belt. The tubular support may be segmented to facilitate removal in confined areas and to permit repair or replacement of individual segments.