Abstract: Method and apparatus for bending metal tubes such as for furnace heat exchangers. After the bend die is rotated 180.degree. to make a bend, an upper section of the bend die is split from a lower section, and the upper section is then rotated approximately 90.degree.. In such manner, a portion of the upper section is displaced laterally to vacate a region directly above the lower section. Therefore, in moving the tube forwardly to a new location for a subsequent bend operation, a portion of a previous bend passes through the vacated region thereby enabling sequential bend angles that are less restricted than without rotating the upper section of the split die.

Abstract: A cathode of a crossed field device includes a first electrode and a second electrode disposed about and dielectrically spaced from the first electrode. In a preferred embodiment the electrode comprises a pair of electrodes, a first one of the pair being a masking electrode disposed about and dielectrically spaced from the first electrode and a second one of the pair being an emitter electrode disposed about and dielectrically spaced from the masking electrode.

Abstract: Method and apparatus for removing radon decay products wherein a fan directs air through a conductive cylinder that is grounded. Positioned axially within the cylinder is one or more cylindrical brushes, each having a shaft and radially extending conductive bristles with distal ends spaced from the cylinder. The shaft is connected to the fan so that the bristles rotate. Also, a static electric potential is applied to the bristles. The relative motion of the air and bristles is particularly effective at enhancing molecular diffusion to cause small unattached radon decay products to plate out on the bristles. In contrast, the electrostatic charging of the bristles and the resulting diffusion charging is particularly effective at exerting a force on larger particles to which radon decay products are attached thus causing the particles to migrate and plate out on the cylinder.

Abstract: A circuit for compensating for GaAs FET amplifier gain variations over a frequency band as a function of temperature. The circuit includes a passive equalizer circuit having a fixed gain over the frequency band and an active equalizer circuit having a gain which varies over the frequency band as a function of temperature. The passive and active equalizers are coupled in series. The active equalizer circuit comprises varactor diodes in a low pass filter arrangement with the bias voltage of the varactor being provided by an external driver controlled by a temperature sensitive thermistor. As the value of the varactor's junction capacitance is increased (as a function of the temperature controlled bias voltage), the cutoff frequency of the low pass filter decreases.

Abstract: A microwave oven having microwave absorbing material disposed in a top portion of the microwave oven cooking cavity above a grease shield. By absorbing reflected microwave radiation, this feature reduces the tendency of overcooked edges, particularly in low profile foods such as pizza. An additional feature includes a cylindrical member disposed around the microwave antenna to provide a directive pattern of microwave energy in the cooking cavity. The microwave oven provides improved cooking uniformity for foods such as pizzas or pies.

Abstract: An improved dual polarized antenna element for use in planar array antennas. The antenna element includes a conductive sheet having a forwardly positioned notch and a pair of spaced rearwardly extending slot portions formed therein. The notch is adapted for coupling radio frequency energy between free space and the antenna element and the pair of slot portions are electrically coupled to the notch. A power divider/combiner is provided and is preferably interconnected with a power combiner/divider through branches of equal phase length. With this arrangement, reactive power divider induced off-axis scan blindness caused by an odd mode coupled field is prevented. Additionally, an antenna module comprising a pair of such antenna elements disposed in intersecting relationship is provided with a coincident phase center.

Abstract: A bulkhead for a tumbler clothes dryer wherein the bulkhead panel is stamped as a unitary part from a single metal blank on a progressive die. The bulkhead panel includes a cylindrical plug portion which fits inside the tumbler drum, and four mounting brackets each extending from a respective one of the four quadrants of the plug portion. Each mounting bracket includes a face portion, a leg portion, and a foot mounting portion. Drum bearings are connected to the bulkhead panel to form the bulkhead. The rear bulkhead mounts to the back panel of the cabinet, and the front bulkhead mounts to the front edges of the two cabinet side panels.

Abstract: A washing machine having the cabinet decoupled from the suspension system in order to eliminate undesirable resonance mode walking conditions. The cabinet is frictionally attached to the washer supporting feet. With this arrangement, the effect of the cabinet on the washer/floor natural frequency is eliminated, thereby increasing such natural frequency above the spin speed of the washer. In this way, walking typically occurring at the natural frequency (i.e. when the spin speed matches the natural frequency of the washer and floor system) is prevented. This arrangement further provides decreased cabinet vibration and noise during operation at typical spin speeds.

Abstract: A washing machine having improved resistance toward frictional walking. The washer comprises a cabinet, a tub assembly disposed in the cabinet for processing a wash load and a suspension including a truss-like pedestal for supporting the tub assembly and for permitting the tub assembly to pivot. The supporting feet of the washer are rotatably coupled to the suspension. Preferably, the number of members comprising the suspension is greater than or equal to three times the number of joints comprising the suspension minus eight. With this arrangement, a statically determinant suspension is provided. The substantially continuous contact between the supporting feet and the floor (i.e. the feet automatically conform to the floor surface) increases the frictional resistance, thereby decreasing the probability of frictional walking.

Abstract: An apparatus for fault detection and coupled between a power supply line and a circuit to be powered. When a fault develops in the circuit that causes voltage in the power supply lines to decrease, the power being provided is interrupted from the circuit. Once the fault is removed, power is automatically returned to the circuit.

Abstract: A technique for removing unwanted portions of a metallization layer in a semiconductor structure, without damage to underlying protective layers of silicon dioxide. The metallization layer is formed with an underlying etch stop layer of titanium-tungsten, the removal of which is effected by a very thin layer of aluminum formed beneath the titanium-tungsten. After removal of unwanted portions of the metallization layer, using a plasma etch to which the titanium-tungsten is resistant, corresponding portions of the titanium tungsten layer are removed using a plasma-etch to which aluminum is resistant. The thin aluminum layer functions as a highly effective etch stop in the removal of titanium-tungsten, but is so thin that there is negligible penetration of aluminum into underlying contact regions.

Abstract: A ground fault interrupt circuit with an improved current window detector. The current window detector works by first rectifying the input current in a pair of current mirrors connected in back to back fashion in the feedback path of the input amplifier. The rectified current triggers an output when the rectified current exceeds a predetermined threshold.

Abstract: The method of bending relatively thin wall tubing to form a tubular heat exchanger that has relatively tight bends with controlled wrinkles. For example, 1.75-inch outer diameter stainless steel tube may have a wall thickness of 0.035 inches and be bent using a controlled-wrinkle bend die to a 180.degree. bend having a centerline radius of 2.5 inches. The relatively high tube collapse that results from bending in such manner without the use of a ball mandrel does not detract from performance of the heat exchanger in a relatively low flow rate furnace application.

Abstract: Method and apparatus for determining moisture content of materials by irradiating a sample of unknown moisture content with a narrow frequency band of light at a first wavelength during a first time period and a narrow frequency band of light of a second wavelength during a second time period. The two wavelengths of light have different water absorptive characteristics, and therefore are reflected by varying degrees depending on the surface moisture on the material. The respective reflections are measured by a single common detector, and a value corresponding to the ambient light is subtracted from each measurement. A ratio of the resultant values is then correlated with data derived from precalibration measurements of samples of known moisture content.

Abstract: A refrigerator door hinge including a bracket connected to and extending forwardly from the face of the cabinet on the side to which the door opens. The bracket includes an upper horizontal plate supporting the door, and a lower horizontal plate with a threaded aperture which captures a threaded post of a foot. The bottom of the foot has a pad and during installation, the foot is rotated to lower the foot until the pad contacts the floor thereby providing adjustable height hinge support directly to the floor.

Abstract: A package for electronic components, especially MMIC components, is disclosed. The package is constructed from layers of ceramic cofired to form an annular piece. Metal pieces are brazed onto the top and bottom of the annular piece to hermetically seal the package. Certain of the ceramic pieces are coated with patterns of conductive material before cofiring. The conductive material forms DC power distribution lines to electronic components within the package and low loss RF feedthroughs into the package.

Abstract: A controller for a washing machine with an alternately reversing drive motor wherein an electromechanical timer interfaces in conventional manner to electrical devices, and also switches line voltage to predetermined ones of a plurality of control lines to provide an encoded signal corresponding to the selected agitator stroke profile. The line voltage on the control lines is shifted to a DC voltage level compatible with a microprocessor that decodes the encoded signal, and then provides high rate control signals that gate high power solid state switches that switch line voltage to the respective stator windings of a permanent split capacitor motor. In such manner, the motor is driven in alternately reversing directions and, by way of a speed reducer, drives the agitator of the washing machine according to the selected stroke profile.

Abstract: A microwave oven with a power supply including a transformer having primary and secondary windings, with the primary winding having a plurality of input connections and a secondary winding being coupled to a magnetron. The microwave oven includes a circuit the magnitude of a line voltage supplied to the microwave oven and, in response thereto, for coupling the line voltage to a corresponding one of the input connections to regulate the voltage provided across the secondary winding to the same voltage level regardless of the magnitude of the line voltage.

Abstract: A small volume, broad beam antenna is disclosed. The antenna has four cavity backed elements. Each of the elements is triangular shaped and is mounted such that the narrow portions of the triangular elements are over the center of the cavity.

Abstract: A gas convection oven having a radiant burner and fuel feeding apparatus which enables the single burner to be operated in either a broil mode or a bake mode. In the broil mode, the radiant burner is operated in conventional manner with the flame being held by an inner screen to heat the outer screen to a radiant luminous temperature. In the bake mode, forced air is injected into the burner by a fan thereby providing a leaner fuel-air mixture with higher velocity. As a result, the flame burns outside the outer screen of the burner with the outer screen serving as a flame holder. Therefore, hot combustion gases as produced while the outer screen remains non-luminous.