Abstract: A belt material handling system including conveyor belts supported on a belt conveyor idler support frame. Brackets are provided for supporting one or multiple idler rollers on such a frame. One form of such brackets has a tab for retaining the shafts in the end bracket that can be precisely bent over the shaft end by providing a cut that extends generally at right angles from a slot. The adjacent ends of a center and an outer roller shaft in a center combined bracket are retained by a single tab that can be bent into locking position over adjacent ends of the shafts. A conveyor return bracket can be utilized either as a left- or right-hand bracket or it can be used as a simple rise bracket. This return bracket uses novel shaped flanges which act to position the shaft in an enlarged portion of the slot, then the slotted portion of the shaft is pressed into holding engagement in the narrow portion of the slot.

Abstract: In a power factor corrected AC-to-DC power supply system, a DC-to-DC power converter is coupled to the output of an AC-to-DC power converter in order to produce a regulated DC output signal from a rectified AC input signal. The AC-to-DC power converter and the DC-to-DC power converter each includes a switch for controlling the operation of their respective power converter. The AC-to-DC converter includes an inductor. The system provides power factor correction for minimizing harmonic distortion by including a controller that receives the regulated DC output voltage as a feedback signal, and in response, produces a series of drive pulses having predetermined constant duty cycle. These pulses are simultaneously fed to each switch, to operate the respective converters alternately between ON and OFF states.

Abstract: A grizzly screen apparatus has a screen of grizzly bars having first ends mounted in a transverse end member and second ends placed in a slotted comb member having alternating shallow and deep bed slots. The screen is rotatable about a transverse axis whereby the second ends of secondary grizzly bars in the deep bed slots are lowered relative to the second ends of grizzly bars in the shallow bed slots, resulting in simultaneous steepening of the screen and an increase of the interbar distance, to remove obstructing oversize objects from the screen. Each grizzly bar has a transverse lock bar at the first end which retains the grizzly bar within an aperture in the transverse end member without bolts or other fasteners. Obstructions on the grizzly screen may be cleared without the use of manually operated tools, and if desired, may be cleared by remote control.

Abstract: A forward converter incorporating a low loss snubber and transformer reset circuit is disclosed. The transformer core of the forward converter is reset by the exchange of magnetizing energy between the transformer secondary winding and an appropriately sized capacitor of the reset circuit during the off period of the power switch. The exchange of magnetizing energy from the capacitor to the transformer secondary winding is independent of power switch operation.

Abstract: A paving machine employs an electrically heated screed assembly to uniformly heat a screed plate of the machine. Uniform heating is achieved by inserting a thermally conductive plate between electrical heating elements and the screed plate. An insulation layer may be provided above the heating elements to direct the heat downward into the thermally conductive plate. The heat spreads relatively uniformly throughout the thermally conductive plate, thereby uniformly heating the screed plate. A clamping mechanism is also provided that, when tightened, provides a compressive force, thereby holding the assembly in place. When released, the pressure is alleviated, thus permitting a heating element to be removed for repair or replacement without the need to remove the screed plate.

Abstract: A combination DC/data connector for connecting electrical equipment stacked in a rack to a continuous vertical combined DC/data bus includes a data connector which cooperates with a slot in the DC/data bus assembly to align the DC/data connector with the bus assembly and make contact with data buses on the walls of the slot. The DC/data connector also includes a pair of DC connectors which slide into channels in the DC bus bars of the DC/data bus assembly after the DC/data connector has been aligned with the bus assembly by the data connector. The data contacts of the DC/data connector are mounted on both sides of a printed circuit card which can be slid into the data connector, and which provides the interconnections between the data contacts and the equipment data interface.

Abstract: A connector module for overcurrent protection devices uses a printed circuit board substrate as a support surface for line and load busbar members and auxiliary signal clip connectors disposed on one side of the substrate. Passageways in the substrate enable male current plugs to extend through the substrate to mate with sockets disposed in the busbars. Additional passageways enable auxiliary contact terminals to extend through the substrate. Clip connectors disposed on the substrate are used to make electrical contact to the auxiliary terminals. In a preferred embodiment, the sockets and clips are shaped and dimensioned to mate with the current and alarm contact terminals of a plug-in circuit breaker.

Abstract: In a redundant power supply system, N+1 power supply modules are operated in parallel to provide power to a single load which may be connected via a DC bus and may employ a remote voltage sensing circuit. Each power supply module includes an ORing element that isolates a corresponding AC power supply from delivering power to the load in various conditions representing a fault occurring in the system. Each ORing element and power supply module is coupled to a control circuit that drives the operations of the ORing element. The control circuit includes three comparators and associated circuitry each for detecting one of the following conditions of system failure representing by: the presence of reverse current flowing across the ORing element caused by short circuit in the system, a selective overvoltage condition caused by a power supply delivering too much voltage to the load; and a failure in an AC power supply giving rise to an undervoltage condition.

Abstract: A fold linkage is provided that is usable in combination with a conveyor assembly having a foldable conveyor section and a main conveyor section. The fold linkage includes linkage members and hinge sections that are rotatably attached to each other and that are connectable to the conveyor sections without interference with the conveyor assembly truss members. The fold linkage further includes a pressure operated cylinder that is extendable and retractable so as to fold and unfold the conveyor assembly.

Abstract: In a power converter whose power is supplied by an input power source, a circuit is disclosed for efficiently clamping the peak reset voltage across a primary switch of the power converter and for recycling the energy stored in the clamp during the OFF period of the switch back to the input power source via a second converter through the operation of a plurality of switching transistors in the second converter. The reset energy of the power transformer in the power converter can also be coupled to an auxiliary power circuit via a winding of a transformer in the second converter. The second converter can thus provide auxiliary or stand-by power to maintain the operation of critical system circuits, when the power converter is turned off, e.g., to conserve power, such as in the sleep mode of a portable PC.

Abstract: A telecommunications power system according to the invention includes a power bus and a plurality of batteries that are connected to the power bus. A distribution module is connected to the power bus. A plurality of loads are connected to the distribution module. A plurality of rectifier modules are connected to the power bus and at least one AC power source. A generator provides backup AC power to the rectifier modules when the AC power source is interrupted. A controller is connected to the rectifier modules and the generator. A controller includes a battery recharging control module that allows the user to select a first mode of operation that allows the generator to recharge the battery when the generator provides the backup AC power. A second mode of operation prevents the batteries from recharging when the generator provides the backup AC power.

Abstract: A current management system for a telecommunications power system includes a power bus, a communications bus, and a distribution module connected to the power bus and the communications bus. A plurality of loads are connected to the distribution module. A plurality of rectifier modules are connected to the power bus, the communications bus and to at least one alternating current source. Each of the rectifier modules includes a neuron that generates a rectifier current signal for the rectifier module. A master controller that is connected to the communications generates an average current signal from the rectifier current signals. The neurons generate a first rectifier control signal that slightly modifies current that is output by the rectifier modules based upon the average current signal and the rectifier current signal. A temperature sensor senses a temperature of each of the rectifier modules. The master controller generates an average temperature signal from the rectifier temperature signals.

Abstract: A forward converter circuit that includes elements capable of generating a zero volt switching (ZVS) signal across the power switch. The ZVS generating elements include a series combination of a switch and shunt inductance, which are connected in parallel across the primary winding of the power transformer. An offset capacitor is placed in series with the shunt inductance and is operated in conjunction with a control circuit to couple the magnetizing current from the primary winding of the power transformer and use it to charge the offset capacitor. This provides zero volt switching of the power switch at turn-on and turn-off, and reset of the core of the power transformer without the use of a tertiary winding. The circuit also achieves added protection of the power switch without the use of an active clamp.

Abstract: The use of synchronous rectifier MOSFETs in the secondary circuit of AC/DC converters is made possible in synchronous rectifier unfriendly topologies such as flyback converters by sensing the onset of forward current in the MOSFET drain-source circuit, optionally converting that current information into logic level signals, and using the information or signals to drive the gate of the synchronous rectifier MOSFET.

Abstract: A boost converter topology is disclosed. The boost converter includes a resonant network comprising a saturable element, coupled to three series interconnected resonant diodes. In operation, the first of the three interconnected resonant diodes is a fast recovery type diode such that it stops conducting before the remaining resonant diodes. Due to the fast recovery of the first resonant diode and the configuration of the resonant network, the voltage across the auxiliary control switch of the boost converter does not drop before being turned on, thereby eliminating power losses associated with turning on the control switch.

Abstract: A method and an apparatus are disclosed for cutting rumble strips in the surface of a roadway. The apparatus is a self-propelled machine which includes a frame and a drive mechanism mounted to the frame and adapted for advancing the machine across the surface of the roadway. The machine also includes a generally cylindrical cutting drum that is mounted on the frame for rotation about an axis that is disposed generally parallel to the surface of the roadway. A plurality of cutting teeth are mounted on the outer surface of the drum in a predetermined pattern, and a mechanism is provided for rotating the cutting drum about its axis. The drum is maintained at a predetermined position with respect to the surface of the roadway so that the cutting teeth will cut into said surface a relatively constant, predetermined depth as the drum is rotated about its axis while the machine is advanced along the surface of the roadway.

Abstract: The dead space at the top or bottom of a power converter bay or cabinet is used for the interconnection of the DC buses of adjacent bays by securing to the DC buses a pair of brackets which between them form a channel into which a linking bus having two conductor bars laminated together and separated by an insulating layer can be longitudinally slipped and fastened. The structure of the invention makes use of the dead space in a power converter bay and also permits interconnection of DC buses while the circuit is live.

Abstract: An apparatus for making asphalt paving material includes a dust collection and distribution system by which aggregate dust that is collected during the heating and drying of aggregate may be introduced into the mixing chamber and distributed over a substantial portion of the area of the mixing chamber. By distributing the aggregate dust over a broader area of the mixing chamber than has been previously known, the mixing effort required to achieve a thorough blending of the dust into the mixture is reduced, and the quality of the asphalt paving composition is improved.

Abstract: A resonant reset forward converter including a gate drive mechanism for controlling the conduction periods of a free-wheeling rectifier on the secondary side of the converter is disclosed. The gate drive mechanism is operative to turn on the free-wheeling rectifier at the beginning of the forward power cycle, maintain the free-wheeling rectifier in the on state during the transformer core reset and dead periods, and provide for rapid discharging of the freewheeling rectifier at the beginning of a subsequent forward power cycle.

Abstract: A combined handle-guard and grip protects the actuator-handle of a circuit breaker from being inadvertently displaced during normal circuit breaker operation while also positioning a user's fingers to automatically trip the circuit breaker into a non-conducting state whenever the user grasps the grip surfaces of the handle-guard to remove or install the circuit breaker. In a preferred embodiment, the shield surfaces form a slot dimensioned to permit the unrestricted movement of the circuit breaker handle. A first grip surface is disposed at one of the slot. A second grip surface is disposed at the other end of the slot. A passageway in the second grip surface is shaped and positioned so that a distal portion of the circuit breaker actuator-handle extends through the passageway when the circuit breaker is in an on-position.