Abstract: The present invention concerns improvements in the use of polyester materials in arc quenching applications, particularly in the cutout fuse tube industry. In one embodiment of the present invention a fuse tube is disclosed as comprising a laminate two-layered structure including as its inner layer, (or liner), a heat-treated polyester filament winding supported in a cured cyclo-aliphatic epoxy resin matrix. The outer layer includes wound glass filaments supported within a cured epoxy resin matrix. The heat treatment of the polyester filament substantially improves the mechanical and electrical character of the fuse tube.

Abstract: The method includes aligning a first plurality of cylindrical workpieces of a first diameter such that the longitudinal axes thereof are substantially coincident and welding the workpieces together end-to-end to form a cylindrical member of a desired length. The welding step includes rotating the workpieces about their longitudinal axes while maintaining a welding electrode at a fixed position along the workpieces and at a fixed distance from the outer circumference of the workpieces. The method includes cutting openings in the cylindrical member wherein the cylindrical member is rotated about its longitudinal axis while causing a cutting means to move linearly along the length of the cylindrical member. In one embodiment, the method is repeated with a second plurality of cylindrical workpieces of a greater diameter with some of the steps in processing the first and second plurality of workpieces being carried out at substantially the same time. Other forms of the apparatus and method are disclosed.

Abstract: The present invention provides a dielectric paper frame structure suitable for use in a shell-type housing for supporting a small number of discrete electronic components in spaced-apart, non-contacting and electrically insulating relation from the walls of the housing. The frame structure comprises a thin elongated unitary piece of dielectric paper having two opposing major surfaces and two edges in contact with opposing walls of the housing. Along the edges of the frame structure there are provided substantially V-shaped slots which receive non-insulated leads of the electrical components such that the electrical components are located between the edges of the frame structure. The novel paper frame structure replaces a printed circuit board.

Abstract: The self-adjusting limit switch assembly of this invention has two switches mounted on a slide for sliding movement on a bracket. A transverse slot in the slide has two facing surfaces. The switches are mounted on each side of the slot with their operating members extending slightly past the slot. The actuator is positioned to extend into the slot. When the brakes are first moved to the brake released position the actuator engages not only the operating member of the switch on that side, but also a wall of the slot and moves the slide to a brake released position thereby correctly adjusting the position of the switches. When the brakes require adjustment due to wear, the actuator engages the operating member of the second switch, as before, causing an indicator to function.

Abstract: A chuteless rotary scything mulching lawn mower is described which is particularly adapted to be powered by an electric motor including sealed motors. The cutting chamber includes a toroidal portion bounded by concentric skirt walls wherein the cross sectional area of the toroid increases towards the inner skirt. The inner skirt slopes downwardly towards the axis of the cutting blade, and terminates close thereto so as to reduce air leakage from the toroid. Air passage openings are provided into the housing on the axial side of the inner skirt through which cooling air is drawn for the motor. This air stream combines with air from the toroidal chamber which is redirected by the inner skirt wall to distribute grass cuttings over a comminuting portion of the blade. The blade is sharpened to a chisel edge along the upper surface thereof, the bevelled surface of the chisel edge functioning as an air propelling surface.

Abstract: Nuclear fuel for use in nuclear reactors is provided in the form of a nuclear fuel element with an interior barrier layer interposed between the sheath and the fuel. The barrier layer incorporates particles of copper in finely divided form to provide by combination with cadmium, which is released during irradiation of the fuel, a stabilized copper-cadmium compound localized intermediate the fuel and the sheath, thus impeding attack on the sheath by the released cadmium. There is further provided a simple, low cost method for applying the barrier layer in a nuclear fuel element.

Abstract: A reservoir for an electric kettle is defined by a dome shaped shell and a planar inner bottom, which are fastened together mechanically having a room temperature vulcanized silicone rubber filler located therebetween to act as a seal. The shell is skirted by an inwardly projecting annular lip and has an inwardly projecting annular shoulder parallel with and spaced from the lip. The inner bottom is bounded by a downwardly extending annular flange, the top edge of which abuts the bead and the bottom edge of which engages the lip. The form of the kettle components permits the interior of the shell to be coated between the lip and shoulder with an annular coating of the silicone rubber whereat the inner bottom is readily snapped into position in the shell during assembly of the kettle.

Abstract: An interface apparatus, for remotely controlling a plurality of solenoid actuated switching relays having first and second energizing coils, is capable of providing momentary first and second electrical signals respectively in response to an interruption of an input signal to the apparatus and the initiation of the input signal. The interface apparatus includes a first comparator sensing a change in the input signal, a second comparator sensing a change in the output of the first comparator so as to maintain the second comparator output 180 degrees out of phase with the first comparator output, and first and second monostable multivibrators that each have a trigger input connected to the output of a corresponding comparator so as to generate a momentary electrical signal when the trigger input senses a negative excursion in a change of state at the output of the corresponding comparator.

Abstract: An electric lawn mower having a permanent magnet motor and a dynamic braking feature includes a rectifier which is assembled in a switch-box. The novel arrangement of the rectifier in the switch-box assembly is attached to an upper portion of the handle of the mower to permit use of standard three wire cord for connection between the switch-box and the motor.

Abstract: In the processes of nuclear fuel manufacture, scrap material such as uncontaminated reject powder and reject pellets, which would previously have been reprocessed chemially in conversion of the uranium values by dissolution into liquid form, is now mechanically reduced by crushing in a substantially inert atmosphere and converted to a slurry having between about 70 to 85 weight per cent solids, and then attrition milled utilizing scrap sintered UO.sub.2 pellets as the reducing medium. Grinding swarf generated during the centerless grinding of UO.sub.2 pellets may also be recycled provided it is sufficiently pure.

Abstract: A remote control wiring system is provided with a transformer that supplies a low voltage signal to a low voltage sub-system. The sub-system includes a diode circuit comprising four diodes which permit energization of a first set of relays on a positive portion of a sinusoidal signal and of a second set of relays on the negative portion of the signal. A pair of triacs are provided that move the relays of both sets either in a first direction to open their higher voltage load circuits or in a second direction to close their load circuits. Previous wiring systems did not include the 4-diode circuit and were limited in capacity to control only a single gang of relays. By virtue of the improved system the capacity of the system is reliably doubled, by utilizing the whole of the low voltage control signal.

Abstract: This invention relates to a system for protecting an amortisseur winding during the starting of a synchronous motor. The system compares the actual slip frequency of the accelerating motor with predetermined slip frequencies. These predetermined slip frequencies are each associated with a timer which measures successive time segments. Each timer is stopped when the actual slip frequency, which decreases as rotor speed increases, is less than the associated predetermined slip frequency. When the timer is stopped a successive timer is started. In this manner the acceleration of the motor is broken up into time segments. The initial timer is started when the motor starts. The final timer is stopped when the rotor field current is applied to bring the motor into synchronism. Should any timer be permitted to have its timed segment expire before being stopped, the motor is shut down. There is also provided a thermal memory which receives information from the expired timer as to its associated slip frequency.

Abstract: In a percussive rock bit or similar tool wherein cemented carbide cutting inserts are retained in open radial slots in the head of the tool, an improved method of mechanically retaining the inserts. The inserts are provided with a plurality of elongated radially aligned serrulations along each flank thereof, the thickness of the insert as measured between the crests of opposing serrulations being such as to provide a substantial interference with the slot wall. The inserts may be cold fitted by sliding along the slot, following which body material is peened so as to overlay a small chamfer at the base of the outwardly facing wall of the inserts. The inwardly facing walls of the inserts may be inclined so as to retain the center plug of the rock bit mechanically.

Abstract: A rotary blade lawn mower has a grass collecting bin secured to the deck thereof, preferably wholly within the wheelbase of the lawn mower. A squirrel tail duct transfers grass cuttings from the cutting chamber to the bin. The elbow portion of the duct hinges aside to provide access for emptying the bin. Automatic means is provided for closing the duct as the elbow portion is moved to its non-obstructing position. The arrangement is particularly suitable for relatively lightweight electrically powered walk-behind lawn mowers.

Abstract: A corona discharge monitor system for a dynamoelectric machine, particularly for large salient pole generators, has an antenna mounted on a rotor pole. The antenna sweeps over the stator slots and picks up radio frequency signals produced by corona activity occurring in the structure of the stator bars. A rotary coupler, having a rotating portion fixed to the shaft of the machine and a fixed portion adjacent to the rotating portion, couples the signal to a signal conditioner. A trigger signal synchronized with the rotor rotation and with a known reference to antenna position and derived from the power system line frequency, is used as one input to a storage device such as a variable persistence oscilloscope. A first output of the signal conditioner represents the peak amplitude of the corona discharge and a second output represents the number of corona occurrences and these are applied to the storage device.

Abstract: A control circuit for an electrical precipitator having a high voltage transformer with a bridge rectifier between the secondary of the transformer and the high voltage precipitator electrodes. The control circuit includes a pair of oppositely poled main thyristors in the primary circuit with a firing arrangement to trigger the main thyristors to maintain desired conditions at the electrodes. The primary circuit does not require a current limiting reactor to limit primary current when a spark discharge takes place at the electrodes. A pair of auxiliary thyristors are each connected in series with a capacitor. Each capacitor and the respective auxiliary thyristor form a branch and these two branches are each connected in parallel with the main thyristors. A rectifier is connected to keep the capacitors charged in opposing directions.

Abstract: In a power circuit breaker a trip mechanism is provided normally to oppose the large opening forces associated with the separable contacts of the breaker and to hold the contacts closed. The trip mechanism in response to overload current conditions collapses and trips open the breaker contacts. Forces related to the opening force of the breaker contacts are present throughout the trip mechanism when the contacts are closed. The trip mechanism provides two eccentric latch mechanisms in series each of which reduce the magnitude of the forces acting in the trip mechanism that are related to the opening force. The two latch mechanisms are each mounted to a pivot for rotation therewith. A force related to the opening force is applied against each latch mechanism. Because the pivot for each latch mechanism is eccentric to the line of force acting against the latch mechanism, the force translates into a rotational force that tends to rotate the latch mechanism and pivot.

Abstract: An automobile engine coolant heater for connection to hoses of the engine coolant systems has a elongated cylindrical jacket portion defining a coolant flow path from an inlet at one end to an outlet at the other end. A metal sheathed heating element is located within the flow path and includes elongated heat generating leg portions. A thermostat for regulating operation of the heating element is mounted in heat conductive relationship on a flattened exterior portion of the jacket. An elongated, open ended metallic heat transfer tube provides a thermal bridge between the heating element leg portions and the interior surface of the flattened portion of the jacket. The heat transfer tube and heating element legs are in axial alignment with the longitudinal axis of the jacket to minimize flow resistance through the flow path. The heat transfer tube is brazed to the leg portions and to the flattened portion.

Abstract: A cooling system for an axial air gap dynamoelectric machine having a discoidal rotor provides liquid cooling to the stator or rotor or both. The cooling system is arranged so that removal of a few parts will either expose the length of the liquid conducting passages or expose the end of a straight liquid conducting portion of a passage so that the cooling passages may be easily cleaned. In one form for stator cooling there are grooves in the outer wall of the stator with a cover plate over the grooves to form passages. An inlet and an outlet are provided in the cover plate. Removal of the cover plate exposes the groove for cleaning. In another form for rotor cooling the discoidal rotor has a metallic hub with pairs of straight holes extending through the hub generally parallel to the axis of rotation. A hub ring on one side of the hub has short grooves, forming with the hub, passages connecting each pair of straight holes. An end plate on the other side of the hub has two radially extending holes.

Abstract: Ducting particularly suited for placement over an existing cable run comprises a tubular duct, for example glass filament wound epoxy duct, the wall of which is slit along the length thereof. Opposed to the slit the wall is weakened e.g. by perforating to form integral hinges upon which the duct may be hinged open for the introduction of the cable therein.