Abstract: A magnetic interference prevention system in a printer comprising a plurality of print hammers whose hammering surfaces are disposed in a straight line and a plurality of printing magnets arranged adjacent one another to drive each of the print hammers respectively. In this system when a signal to drive a first printing magnet for a column is provided the driving of at least one of two printing magnets adjacent to the first printing magnet is inhibited for a predetermined period of time. This will prevent three adjacent printing magnets from being driven substantially at the same time.

Abstract: A rapper plunger displacement indicator for an electrostatic rapper control system of the type which supplies a pulse of controlled energy to the rapper coils. Means are provided for sensing current supplied to each rapper coil during the controlled energy pulse. The resultant sensed current is integrated with respect to time over the period of the pulse of controlled energy, and the result of the integration indicates plunger displacement. In a system where a short boost pulse of full lift energy is supplied immediately prior to the lift pulse of controlled energy for enhanced control accuracy, the integration is performed only during the controlled energy pulse, thus ignoring the boost pulse.

Abstract: A printing device having a plurality of print hammers having striking surfaces arranged along a print line and print magnets provided adjacent to one another for driving the printing hammers. A magnetic interference preventing device comprises a memory for storing for each column the excitation lapse time information of the print magnets. A reader which, when exciting each print magnet is started, reads the excitation lapse time information of both print magnets adjacent to each print magnet out of the memory. The reader outputs a signal only when the excitation lapse times of both print magnets are in a predetermined range of time. An inhibitor is used for inhibiting the excitation of each print magnet when the excitation lapse times of both print magnets are within the predetermined range of time.

Abstract: A circuit for selectively controlling bidirectional energization of a plurality of latching solenoid coils and incorporating electrical failure detection means therein. The coils are connected in a series chain and a plurality of independently actuable switching means are provided for connecting a positive voltage potential, a negative voltage potential, or no voltage potential to any of a plurality of terminals defined by the ends of the chain and the junctions between two adjacent coils of the chain. The solenoid coils are energized by a momentary current pulse, and the switching means are selectively actuated to control the direction of the energizing current through any of the coils. A voltage divider establishes voltage potentials at the ends of the chain which vary from a predetermined value during a failure mode of operation of the circuit.

Abstract: A magnetic flip-flop circuit, predominantly used for hydrophone preamplifs, which allows switching capabilities at a remote location while minimizing the number of conductors. In particular, the circuitry is a magnetic flip-flop system which has a multiple-pole, double-throw latching magnetic relay in combination with a single-pole, nonlatching magnetic relay. The combination is coupled to allow a switching of the magnetic latching relay by merely removing the voltage from a single conductor.

Abstract: A comprehensive multiple rapper control system controls rapping intensity with enhanced accuracy, controls a large number of rappers in any desired sequence with intensity control for each individual rapper, and includes alarm circuitry for reliably indicating open circuited and short circuited conditions in the rapper coils or in the electrical connections to the rapper coils. For enhanced accuracy, a short boost pulse of full lift energy is applied immediately prior to a lift pulse of controlled energy. The boost pulse overcomes initial rapper plunger sticking forces so that total rapper plunger lift accurately reflects the electrical energy supplied during the subsequent controlled pulse. Advantage is taken of the relatively constant boost pulse which is supplied to every rapper in the system regardless of the energy supplied during the control pulse to provide an alarm circuit. Current through each rapper plunger lift coil is sensed during at least a portion of the boost pulse.

Abstract: A system for automatically selecting operations in a random sequential manner having at least three electrical channel circuits, each channel circuit including primarily a trigger circuit, a switch circuit and an output circuit. Each trigger circuit includes an electrical conductor component exhibiting a negative resistance characteristic, such as a DIAC, adapted to turn on at a relatively high voltage and turn off at a lower voltage, each trigger circuit including a timer circuit for turning on and off the respective electrical conductor components, but all of the timer circuits having different time constants. The different switch circuits are adapted to be turned on by the signals from the corresponding trigger circuits and are adapted to be turned off by corresponding switch timer circuits, also preferably having time constants with different values.

Abstract: A switch mode driver for a wire matrix printer employs a single power switch circuit to connect one or more solenoids across a DC source or power and to disconnect those solenoids from that source. Enable signals are provided to select any one or all of the solenoids, such enable signals remaining for a predetermined time during which a slewing period, followed by a chopping period, occur and after which energy remaining in the selected solenoids is returned to the DC power source. The initial ramping of current through the selected solenoids occurs when the power switch circuit is closed for a time period determined by an RC circuit, such time period defining the slewing period. Then the power switch opens and the chopping period begins. The charge on the capacitor of the RC circuit is discharged and at a certain voltage point, the power switch is again closed until the charge on the capacitor of the RC circuit again reaches a predetermined voltage at which time the power switch opens.

Abstract: A circuit for the protection of devices from power line transients and accidental shut-down requiring operator performance for restart including a push button switch for resetting holding relays to operate the apparatus.

Abstract: A grounding arrangement is disclosed for microelectronic control of operating devices such as solenoid operated sprinkler valves in an a-c sprinkler system wherein one a-c power line connecting the several valve solenoids is earth-grounded and d-c microelectronic control circuits use the voltage level of the non-grounded a-c power line as a common voltage reference to operate switch means which interruptively supply a-c power to the valve solenoids.

Abstract: The remote control of electrical power through a number of outlets at selected locations in the walls and ceiling of a building structure is disclosed herein. This is accomplished by applying the electrical power from a source through the walls and ceiling of a building structure to the selected locations. At the same time a clock signal of predetermined frequency and amplitude is generated and carried by a cable to a number of encoders which are located at respective control stations remote from the outlets and also to a number of decoders which are located at and associated with the various outlets. Each of these encoders, when actuated, generates a distinct code signal which is carried to all of the decoders on a common line and in synchronism with the clock signal which is provided for coordinating operation of the encoders and decoders. A preselected one of the decoders responds to this coded signal and accompanying clock signal for automatically applying the electrical power to its associated outlet.

Abstract: A relay control circuit for controlling the operation of various electrically actuated devices in a washing appliance such as a dishwasher is disclosed. The circuit employs four relays to provide eight operating functions, including filling, draining, dispensing of additives, water circulation, water circulation with heat, and drying.

Abstract: In a preferred embodiment, a plurality of interconnected demand controllers of the invention, each demand controller being connected to and controllable of one or more different machines (loads) controlled thereby a plurality of the interconnected demand controllers being controlled by others of the interconnected demand controllers whereby a priority of running of particular machines and of non-running of other machines may be predetermined and maintained automatically, and also there being safeguards against intermittent inconsequential variations in activating currents and/or short-term cessations thereof not ordinarily intended to change the sequence or preference, each controller being basically inclusive of a transformer with the load-switch on the high-voltage side as controlled by switch coils thereof of a relay-type located on the low-voltage side in electrical flow series with a normally-closed low-voltage switch of a relay type controlled by other relay switch coils in another different electrical

Abstract: Device for controlling by means of a current program a plurality of solenoid valves operating independently. Each solenoid is provided with a current flow control circuit having two inputs. The first input receives a first control signal which determines the duration of each actuation of the corresponding solenoid valve. The second input receives a second control signal derived from the first signal and of lesser duration. The current flow control circuit then provides a pull current to actuate the solenoid in response to these input signals.

Abstract: A control circuit including at least one switch and a plurality of rectifiers for selectively applying a-c utility power to either or both of two remote electrically-powered apparatus at respective first and second states of rectification by means of a conventional two-wire interconnection cable. Where one of the apparatus is of a type, such as a motor, adapted to be powered by a full-wave a-c, the control circuit includes a relay and relay switch responsive to switch-selectable half-wave a-c for connecting the motor to receive full-wave power. In one disclosed embodiment, the two apparatus comprise a composite smoke detector and lamp fixture, and the control circuit provides continuous power at a first state of rectification to the smoke detector portion of the fixture and switch-selectable power at a second state of rectification to the fixture lamp.

Abstract: A transfer trip circuit has a first station which contains a circuit breaker and a source of control current in which the control current is increased from a first value to a second value in response to the operation of the circuit breaker. A second station is connected to the first station by a pair of pilot wires which carry the control current. The second station contains a circuit breaker which is to be operated in response to the operation of the circuit breaker in the first station, and also contains two relay coils which carry the control current produced in the first station. The first relay coil operates an annunciator when the control current is below its first value to indicate a fault in the pilot wires. The second relay coil operates the trip circuit of the circuit breaker in the second station when the control current in said pilot wires is increased to said second value.

Abstract: A time-proportioning control system is disclosed for controlling an on-off solenoid valve of an earth-working machine, the system having a sensor responsive to an external reference for producing an error signal, an amplifier switch for switching on and off the on-off solenoid valve in response to the error signal and a capacitive feedback circuit connected from the output to the input of the amplifier switch for controlling the on and off times of the solenoid valve dependent upon the magnitude of the error signal.

Abstract: A fail-safe time delay circuit is provided to produce an output a predetermined time, and no less than a predetermined time after an input stimulus. The circuit includes a driving circuit for a pair of relays which are operated at slightly greater than 50% duty cycle and out of phase such that, except when the circuit is de-energized, at least one of the relays is always energized. The contacts of the two relays are employed in a balanced voltage amplifier to produce a bi-polar signal, with the magnitude of both polarities increasing, with the time required for the increase to a defined threshold establishing the time delay. A pair of threshold circuits are coupled to the output of the balanced voltage amplifier such that each threshold circuit (one responding to the positive portion, and the other the negative portion of the bi-polar output) is energized when the respective portion of the bi-polar signal is detected to reach the associated threshold.

Abstract: A light barrier system for monitoring the presence or absence of an obstacle in the monitored area and for simultaneously monitoring itself to detect contamination of the system. A photo-converter emits signals indicative of the light intensity of a light barrier beam and the signal is applied to a first, obstacle switch which is normally open but which closes at a relatively high level of darkness, i.e. when an obstacle is present. A converter signal is also applied to a second, contamination switch which is normally open but which closes at a lesser degree of darkness than the first switch so that both switches can be simultaneously closed. The outputs of the switches when closed are applied to relays to switch the relays between alternative position to indicate (a) the presence of an obstacle in the light curtain area and (b) the contamination of the light curtain system irrespective of whether or not an obstacle is present.

Abstract: A two wire switching system is intended for use in a hostile environment such as a nuclear reactor where temperatures are in excess of 250.degree. or 300.degree. C. and where the use of a switch with a permanent magnet component or a component intended to have remanence is not desirable. The system uses eight reed switches each having three similar windings. No magnetized components are used. The switches are normally closed in the absence of a magnetic field and are opened when a net magnetic field results from current flowing through at least one winding. A pair of conductors interconnects the windings so that each conductor connects certain windings in a series arrangement to ground, giving a unique interconnection for each switch. A control current may be caused to flow in either conductor arrangement at a value of zero or plus or minus A or 2A amperes where A amperes is at least sufficient to cause actuation of a switch when it flows through one winding.

Abstract: A control switch has a switch shaft carrying radially positioned contacts and mounted for reciprocal rotational movement about its axis. A cam profile is fixed to the shaft and has first and second opposed cam surfaces. A driver is mounted to selectively engage the first or second cam surface to drive the switch shaft into a first clockwise position or a second counterclockwise position by remote actuation. The driver is connected to a rotary solenoid and a linear solenoid which allow uni-directional drive translated into two directional drive by the driver.One form of control circuit operates a rotary solenoid and a linear solenoid through a trip and close switch. A first relay is responsive to actuation of the trip switch means or close switch means to energize the rotary solenoid and index the switch shaft to a preselected position holding that position for a preselected time after which the shaft returns to its original position regardless of whether or not the trip switch or close switch are deactuated.

Abstract: A control switch has a switch shaft mounted for reciprocal rotational movement about its axis. A cam profile is fixed to the shaft and has first and second opposed cam surfaces. A driver is mounted to selectively engage the first or second cam surface to drive the switch shaft into a first clockwise position or a second counterclockwise position by remote actuation. The driver is connected to a rotary solenoid which allows uni-directional drive translated into two directional drive by the driver.A control circuit provides rapid actuation and slow release of the rotary solenoid along with operation of a linear solenoid when desired to select between first and second directional movement of the cam profile. The control circuit permits charging a capacitor while rapidly actuating a relay to actuate the rotary solenoid. A resistor provides for slow discharge of the capacitor to maintain the relay actuated over a slow release period after disruption of the charging circuit.

Abstract: Thermostat control of separate heating and cooling apparatus is achieved with a system that requires only a two-conductor connection between the thermostat and the apparatus. A pair of oppositely-poled diodes is employed at each end of one of the conductors of the connection so that when the control system is established, by a selector switch, in the heating mode the half cycles of one polarity of an AC voltage effect the operation of the heating apparatus, whereas when the system is switched to the cooling mode the opposite polarity half cycles cause operation of the cooling apparatus. The invention is especially advantageous when a central air-conditioning system is added to a building where only a two-wire cable connects the thermostat to the existing heating system. Rewiring of the thermostat cable is unnecessary.

Abstract: A control unit is connected, via a data bus, to a plurality of remote field controllers, each of which is in turn connected to a motor starter and status contacts of a respective valve or pump. Binary codes are communicated between the control unit and field controllers to convey status information, regarding a valve or pump, to the control unit. Likewise, command codes are conveyed from the control unit to a pump or valve to effect a selected operation.

Abstract: The invention provides a system for transmitting operational command signals to one or more remote unit ventilator units from a master control panel. A number of selected command signals corresponding to operational modes such as occupied day, night setback, morning ready and load shedding modes may be transmitted over a two-wire electrical transmission line to which the remote units are parallelly connected. The remote units receive and respond to the command signals by initiating the commanded mode.

Abstract: An accessory for a garage door opener which includes a circuit which is energized when the garage door operator is actuated and which can be used to energize a power circuit as, for example, a lamp so as to provide illumination upon energization of the garage door operator. The lamp automatically turns off after a pre-set time and can also be manually controlled by an on-off switch.

Abstract: A driver circuit for limiting the magnitude of current flowing through a solenoid wherein the level of the current flowing through the solenoid is sensed and fed back to a driving switch. A level of current above a set level cuts off the drive voltage allowing the current in the solenoid to decay. A timing means fixes the time that the driving switch is off. During off times a conserving voltage is applied to the solenoid to prevent the rapid decay of the solenoid current.

Abstract: The output of a first monostable multivibrator controls output-driving dees to provide an operating current and voltage to latch each magnetic latching relay in a first position. The first multivibrator then triggers a second monostable multivibrator whose output in conjunction with logic means controls output-driving devices to provide an operating current and voltage to latch selected relays in a second position.

Abstract: A magnetic device comprising two permanent magnets, armature members forming with said magnets a closed magnetic circuit and an external air gap, and means for reversing the direction of magnetization of one of the magnets, whereby the flux is prevented to close along the magnetic circuit and caused to close through the air gap, or caused to close along the magnetic circuit, the flux in the air gap then being suppressed. The said means consist of two distinct coils wound about the magnets. One of the coils is energized for establishing the flux in the air gap, while the other coil is energized for suppressing the flux in the air gap.

Abstract: A control system for controlling the operation of an air conditioning system having a heating mode capability, a cooling mode capability, and a common air distribution fan motor including a thermostatically operated heat switch; a thermostatically operated cool switch; a common fan motor control relay for operating the system fan motor; a cool control relay for operating the system in the cool mode energized upon closure of the cool switch; a heat control relay for operating the system in the heat mode energized upon closure of the heat switch; and, a diode network connecting the coil of the fan control relay to the cool switch and to the heat switch to energize the common fan control relay when either the heat switch or the cool switch is closed while preventing feedback from the heat control relay through the cool switch when the cool switch is closed and while preventing feedback from the cool control relay through the heat switch when said heat switch is closed.