Abstract: A high-speed constant-horsepower motor includes a rotor and a stator having a plurality of groups of windings which are separately driven. In one mode of operation, the polarity of the voltage applied to each winding is such that the windings behave as distinct electromagnets, each defining a separate magnetic pole. In another mode of operation, the polarity of voltage applied to some of the windings is reversed, such that pairs of adjacent windings behave as single electromagnets. In the latter mode, the effective number of magnetic poles is reduced by a factor of two. Thus, the effective number of magnetic poles of the motor can be varied electronically, even while the motor is operating. The invention makes it possible, in one example, to operate the motor as an eight-pole motor at low speeds, and as a four-pole motor at high speeds. The effective motor constants are changed appropriately from eight-pole to four-pole modes.

Abstract: A security electrical power interrupt apparatus prevents usage of an electrical appliance such as an electric stove, or other electrically operated device. The apparatus includes a relay controlled by a micro-processor based programmable controller. The device includes a detachable component through which data is input. Data is input to the detachable component through a key pad. A software computer program operates in the controller and causes the relay to disconnect the supply power from the device if any attempt is made to operate the appliance or device in a manner which draws electrical current exceeding a preset limit while the controller is in an interrupt mode.

Abstract: An apparatus for controlling the speed of an induction motor includes a first winding and a second winding. The first winding and second winding are adapted to be coupled to an AC source for supplying an AC input signal. A first switching device is coupled to the first winding and a second switching device is coupled to the second winding. Each of the switching devices is operative in a low impedance state enabling current to flow through the associated winding of each switching device and a high impedance state preventing significant current flow through the associated winding of each switching device. A controller switches each of the switching devices from the high impedance state to the low impedance state in a sequence for controlling the current in the windings, which induces a phase shift between the AC voltages across the windings.

Abstract: A fastener including a body, a shroud rotatably mounted on the body, and a resilient retaining ring located in opposed grooves between the shroud and the body, one end of the body extending outwardly beyond the shroud, and a frustoconical outer surface on the shroud which has its larger side proximate the end of the body which extends beyond the shroud.

Abstract: A fail-safe closed damper for installation in a system of ducts. The damper includes at least one damper blade connected to a spring-loaded shaft. A power-actuated unit is employed to disengage a coupling which interconnects the spring-loaded shaft to an operating linkage. The use of the power-actuated unit ensures that the damper will be tripped at the appropriate predetermined temperature and will not be affected by the large frictional forces imparted on the components of the damper by the biasing spring or by such external factors as dust, humidity and dirt. The damper employs a sensor having dual sensing devices and which is centrally disposed in the duct to ensure receipt of a representative sample of airflow. The damper further includes a damper blade position indicator for sensing whether the damper blade is open or closed.

Abstract: An orientation sensor especially suitable for use in an underground device is disclosed herein. This orientation sensor includes a sensor housing defining a closed internal chamber, an arrangement of electrically conductive members in a predetermined positional relationship to one another within the chamber and a flowable material contained within the housing chamber and through which electrical connections between the electrically conductive members are made such that a comparison between an electrical property, specifically voltage, of a first combination of conductive members to the corresponding electrical property of a second combination of conductive members can be used to determine a particular orientation parameter, specifically pitch or roll of the sensor.

Abstract: A novel digital servo valve system for use in controlling a displaceable actuator includes a valve body with ports, a valve spool displaceable within the valve body to regulate fluid flow through the ports, and a motor having a drive shaft which displaces the valve spool. The system is characterized by a null adjustment mechanism which makes a null rotational position of the drive shaft coincide with a null position of the valve spool, at which positions the valve spool cuts off fluid flow through the ports. The null adjustment mechanism provided in accordance with the present invention permits the null positions of the valve spool and stepper motor to be adjusted without having to disassemble the servo valve.

Abstract: A high-voltage switching circuit is formed of a series combination of switches, each of which is rated for use at a voltage lower than that of the power supply. The switches are connected in series with inductors, the inductors being magnetically coupled, in an anti-phase manner. A pair of capacitors, having substantially equal values of capacitance, are connected, respectively, in parallel with each series combination of a switch and inductor. The inductors and capacitors together insure that no more than one-half the total voltage of the power supply will ever appear across either switch. The series combination of switches can be used in place of a single switch, and permits the use of switches rated at low voltage to be combined to form an overall switch which works reliably at a higher voltage.

Abstract: An improved system for recovering and charging refrigerant of a refrigeration system. The system includes a series arrangement of two gas compressors that boost the pressure of the recovered refrigerant to a high enough level for storage in a DOT-3AA type cylinder. The recovered refrigerant is not condensed to the liquid state during recovery, nor is the cylinder chilled. The second high-pressure compressor includes a free-floating piston within a cylinder. The piston is hydraulically actuated. The system includes microprocessor control. The system is well suited for recovery of refrigerants such as R-13, R-23, R-503, and SUVA-95.

Abstract: An inverter by pass safety switch for rerouting electrical power either through or around AC variable frequency inverter drives during electrical disturbances, thus allowing a motor to continue operation. The switch works in a mechanical fashion, and comprises a contact block containing electrical contacts and cams operably connected to the contacts and mounted on a shaft that can be turned by an operator. The cams are shaped and mounted on the shaft in such a way to provide a desired switching pattern when the shaft is manually rotated.

Abstract: A power regulator system provides power to an electrical load. A power level selector generates a reference signal which indicates a desired power level for the electrical load, and a control circuit connected with a AC power source interrupts flow of the AC current for periods of time responsive to a reference system from the power selector. A filtering circuit filters the output of the control circuit and generates therefrom a second output AC circuit which is smooth relative to this interrupted AC circuit. This smooth AC output is applied to the load. A relay is provided to prevent overload conditions from forming adjacent the load in the circuit. Various types of sensors may be used as the power level indicator, such sensors including the light detector as movement detectors, and other electrical sensors.

Abstract: Railway car indexers are disclosed that include a high dog engaging member for engaging a bogey frame behind a railway axle. The high dog is pivotally attached to a dog carriage which is slidably inserted in an indexer track juxtaposed to the railroad track. The high dog is actuated between a raised and a lowered position by a lever arm which is pivotally attached to the dog carriage and a spring-piston cylinder connected to the high dog and the lever arm. The dog carriage is moved back and forth in the indexer track to engage the lever arm and high dog with the bogey frame to move the railway cars. In a reversing indexer, the dog carriage includes opposing high dogs for engaging the bogey frame behind either axle for moving the railway cars in either direction. The single direction or reversing direction indexers include a dog carriage on one or both sides of the railroad track.

Abstract: A method of installing a groundwater containment system is provided utilizing a powered trenching apparatus. The apparatus includes a boom at an end thereof; a trenching tool coupled to the boom; and frame structure mounted with respect to the boom. The frame structure is separated into at least first and second adjacent compartments. Each compartment has an inlet opening and an exit opening. The method includes advancing the trenching apparatus to create a single trench with the frame structure being disposed within the trench. Filter material is fed through the inlet opening of the second compartment. A first, impermeable wall panel is inserted through the inlet opening of the first compartment.

Abstract: An intrinsically safe power supply unit is provided for conditioning power supplied by a power source. An input power converter connected to the power source receives current from the power source. A direct output crowbar and discrete impedance elements dissipate and limit the energy in the power supply unit that would otherwise be delivered to an external fault. In addition, the direct output crowbar extracts energy from any external storage elements. An adaptive shut down circuit distinguishes nominal load conditions including load changes from an external fault. A multistage LC power filter is used to minimize the stored energy that would be deliverable to an external fault or dissipated by the direct output crowbar and discrete impedance elements. The combination of the direct output crowbar, discrete impedance elements, adaptive shut down detection circuitry and multistage LC power filter significantly improves the level and quality of intrinsically safe power delivered by the power supply unit.

Abstract: Apparatus is are disclosed for selective alteration and control of door movement modes, the apparatus being primarily non-hydraulic and incorporated with a known mechanism which is functional independently from the apparatus in one mode of operation and which includes a piston for controlling door closing characteristics by selected fluid flow within the mechanism. The apparatus includes a motor driven lead screw having a linearly movable shuttle unit mounted thereon, the shuttle unit being positioned relative to the piston of the mechanism to accommodate nonattached contact with the piston to urge the piston, when the shuttle unit is moved, in a direction that will at least provide selective assistance with door opening in another mode of operation.

Abstract: A gearhead with an axially-extending input shaft connected to a motor shaft. A pinion gear and bearing assembly is adapted to connect to the motor shaft. The pinion gear is rotatably and sealably mounted to a recessed mounting surface of the housing to reduce noise, prevent entry of dirt and dust and provide a floating connection. The mounting is achieved with a double-sealed bearing which is configured to float with respect to the housing so that a high tolerance connection is maintained between the pinion gear and the gearhead while accommodating motor shaft misalignment. The invention also relates to a method for mounting the motor shaft onto the gearhead by inserting the motor shaft into the input pinion gear, securing the gearhead to the motor and clamping the input pinion gear to the motor shaft.

Abstract: A nonadjustable shock absorber that can accommodate for variations in weight, and propelling force, and to provide a specific deceleration or reaction force. The shock absorber provides dual function metering that combines soft contact dampening with the self compensating ability to decelerate a wide range of weights.

Abstract: A reader for machine reading a symbol printed on a document. The light source shines light through a form at the location of a symbol printed on the form, and onto an array of light sensitive cells. This casts an image of light and shadow on the array. The array generates a signal in response to that image, which signal is processed to determine the information carried by the symbol. A writer such as a computer printer may also write to the document, and the information written to the document can be stored in a computer in conjunction with the information (such as an identification number) read from the symbol. Also, the method of encoding an identification number in a symbol, and decode it with the reader.