The Scott-fetzer Company

Clopay Corporation

Maw H Lee

Barry V Prehodka

John E Keim

Chun F Chen

Carl A Gedeon

Eugene V Erjavec

Timothy R Louis

A data totalizer for use with a fluid flow chart recorder is disclosed. The chart recorder may be for a gas well to record the flow of gas into a collection pipe and such chart recorder has a movable chart, usually a circular chart, with a first marker pen to record on the chart a static pressure within the pipe collection system and a second marker pen to record on the chart a fluid flow signal in accordance with a differential pressure across an orifice in the gas well pipe, and with first and second fluid pressure motors in the chart recorder to move the first and second marker pens. The data totalizer includes first and second linear variable displacement transformers, with linkage connected directly in the chart recorder to move in accordance with movements of the pens and connected to move the linearly displaceable elements in the two transformers. An electronic multiplier is provided to multiply together the electrical outputs of the first and second transformers to obtain a product. An electronic circuit is provided to calculate the square root of such product to obtain an electrical signal proportional to the rate of fluid flow. This signal may be multiplied by a time signal to obtain the total quantity of fluid flow, such as in cubic feet.

Fluid flow totalizer

A door operator includes a motor-driven mechanism to move a door between an open position and a closed position in response to activation of an improved control circuit. The improved control circuit includes circuitry to initialize the sequence of operation of the motor upon connection of power after installation of the door operator or upon restoration of power after a power outage. Obstruction detection circuitry is also included in the control circuit to stop or reverse the motor if the door encounters an obstacle during movement between the open and closed positions. Time delay circuitry cooperates with the obstruction detection circuitry so as to prevent stopping or reversing the motor due to the inertia of the door and of the drive mechanism as the door starts to open or close upon activation of the control circuit. During the time delay period, however, further manual activation of the control circuit is operative to stop and/or reverse movement of the door. As the door moves in one direction, movement can be stopped and restarted in the opposite direction upon consecutive manual activations of the control circuit. When the door nears the closed position, timer circuitry is activatd to energize the motor for a predetermined time or until sufficient resistance to door movement is met to activate the obstruction detection circuitry whereupon the motor is stopped. Maximum run-time circuitry is also included to set the maximum time allowable for energization of the motor to move the door in either direction between the open and closed positions.

Control circuit for a motor-driven door operator

Power factor controller for induction motor

First and second input currents to a three-phase AC induction motor of either delta or wye winding configuration are directly regulated by a pair of phase-triggered, gate-controlled, semiconductor switches series-inserted between the motor and two phases of its three-phase AC power source, the third input current being the Kirchoff resultant of the two regulated input currents. The half-cycle firing points or firing angles of the gate-controlled switches are varied together to apply more or less power to the motor as a function of mechanical load to optimize the power factor of the motor. Voltage imbalances in the motor windings caused by directly regulating only two of three input currents are tolerable due to the current limiting effect of the gate-controlled switches when the induction motor is at less than full mechanical load, such current limiting minimizing heat losses (I.sup.2 R) caused by the voltage imbalance condition.

Power factor control of a three-phase induction motor

A phase-triggered, gate-controlled AC semiconductor switch, in series with an induction motor and its AC supply, optimizes power flow to the motor under changing mechanical load conditions by varying the amount of supply voltage applied to the motor over each half-cycle of the AC supply. Such power flow optimization is effected by utilization of a control voltage generated by the freewheeling induction motor during nonconduction periods of the switch. The triggering point of the switch relative to the preceding zero crossing point of the supply voltage, that is, the switch firing angle or delay angle, is varied by the control voltage augmenting to a varying degree the charging rate of a capacitor that triggers the semiconductor switch into conduction. Under increasing mechanical load conditions, the control voltage decreases, the decreased control voltage accelerating the charging rate of the capacitor to trigger the switch into conduction at a reduced firing angle, wherein power flow to the motor is increased. Conversely, under decreasing mechanical load conditions, the control voltage increases, the increased control voltage decelerating the charging rate of the capacitor to trigger the switch into conduction at an increased firing angle, wherein losses caused by reactive current in the less-than-fully loaded induction motor are reduced with a resultant optimization of power factor.

Simplified power factor controller for induction motor

Electrically parallel but positionally serial, helically wound segments of heating wire in a cable are each controlled by a chip (thermistor) and are connected to the cable proper by wrapping around notches formed in the insulation of the cable proper at first one side and then the other of the cable. The inner and outer-faces of each chip are connected into each segment by direct contact or by leads at spaced points between which the heating wire is severed. An extruded casing is shrunk-fit over the other parts.

Method for forming self-regulating heat trace cable

A phase-triggered, gate-controlled AC semiconductor switch of the thyrister type in series with an induction motor and its AC supply, optimizes power flow to the motor under changing mechanical load conditions by varying the amount of supply voltage applied to the motor over each half-cycle of the AC supply. The triggering point of the semiconductor switch relative to the preceding zero crossing point of the supply voltage, that is, the switch firing angle or delay angle, is varied as a function of mechanical loading on the motor by means of a load current induced feedback voltage which varies the breakdown or triggering voltage of a two-transistor switch functioning as a variable trigger diode between the gate of the semiconductor switch and a turn-on capacitor charged by the AC supply voltage during non-conducting periods of the semiconductor switch. Under increasing mechanical load conditions, the feedback voltage increases in proportion to increasing load current, the increasing feedback voltage lowering the breakdown voltage of the two-transistor switch to trigger the semiconductor switch into conduction at a reduced firing angle, wherein power flow to the motor is increased. Conversely, under decreasing mechanical load conditions, the feedback voltage decreases in proportion to decreasing load current, the decreasing feedback voltage raising the breakdown voltage of the two-transistor switch to trigger the semiconductor switch into conduction at an increased firing angle, wherein losses caused by reactive current in the less-than-fully-loaded induction motor are reduced with a resultant optimization of power factor.

Power factor controller for an induction motor using transistor switch

A phase-triggered, gate-controlled AC semiconductor switch, in series with an induction motor and its AC supply, optimizes power flow to the motor under changing mechanical load conditions by varying the amount of supply voltage applied to the motor over each half-cycle of the AC supply. The triggering point of the switch relative to the preceding zero crossing point of the supply voltage, that is, the switch firing angle or delay angle, is varied as a function of mechanical loading on the motor by means of a load current-induced feedback voltage augmenting to a varying degree the charging rate of a capacitor which triggers the semiconductor switch into conduction. Under increasing mechanical load conditions, the feedback voltage increases in proportion to the increasing load current, the increasing feedback voltage accelerating the charging rate of the capacitor to trigger the switch into conduction at a reduced firing angle, wherein power flow to the motor is increased. Conversely, under decreasing mechanical load conditions, the feedback voltage decreases in proportion to the decreasing load current, the decreasing feedback voltage decelerating the charge rate of the capacitor to trigger the switch into conduction at an increased firing angle, wherein losses caused by reactive current in the less-than-fully-loaded induction motor are reduced with a resultant optimization of power factor.

A door operator includes a motor-driven mechanism to move a door between an open position and a closed position in response to activation of an improved control circuit. The improved control circuit includes circuitry to initialize the sequence of operation of the motor upon connection of power after installation of the door operator or upon restoration of power after a power outage. Obstruction detection circuitry is also included in the control circuit to stop or reverse the motor if the door encounters an obstacle during movement between the open and closed positions. Time delay circuitry cooperates with the obstruction detection circuitry so as to prevent stopping or reversing the motor due to the inertia of the door and of the drive mechanism as the door starts to open or close upon activation of the control circuit. During the time delay period, however, further manual activation of the control circuit is operative to stop and/or reverse movement of the door. As the door moves in one direction, movement can be stopped and restarted in the opposite direction upon consecutive manual activations of the control circuit. When the door nears the closed position, timer circuitry is activated to energize the motor for a predetermined time or until sufficient resistance to door movement is met to activate the obstruction detection circuitry whereupon the motor is stopped. Maximum run-time circuitry is also included to set the maximum time allowable for energization of the motor to move the door in either direction between the open and closed positions.

Flexible temperature self regulating heating cable

A radio receiver equipped central control unit continuously monitors at least one battery-powered remote transmitter activated in response to predetermined alarm conditions, such as open doors and windows, fire, smoke, low transmitter battery voltage, and the like. In its activated condition, the transmitter is cycled to radiate a one-second duration radio frequency signal every 30 seconds, such cycling being established by transmitter timer circuitry series-inserted between the transmitter and its battery power source. The transmitted signal is received by the central control unit which, in response to the received signal, selects and activates one or more alarm indicators for a predetermined time period. Such selection and activation of particular alarm indicators and the duration of their activation are determined by switching and timing circuitry series-inserted between the central control unit's radio frequency receiver and the various alarm indicators.

Wireless alarm system

Improved traveler and guide rail apparatus for use with a garage door operator includes an elongated guide rail having a longitudinal screw channel and outwardly extending integral flanges disposed along the screw channel. An elongated T-shaped flange extends upwardly from the screw channel. An improved traveler apparatus for use with the guide rail includes a screw-driven traveler and a coupling traveler, each mounted on respective tracks formed by separate outside surfaces of the guide rail. The screw-driven traveler carries a nut engaging a screw in the screw channel through a slot between the flanges and further includes opposed U-shaped channels slidably mounted over the exterior surfaces of the guide rail flanges for slidable movement along the guide rail. The coupling traveler surrounds the screw-driven traveler and a substantial portion of the guide rail and includes a bore in an upper portion thereof, the bore having an interior surface slidably engaging the exterior surface of the screw channel for slidable movement along the guide rail. Upper shoulders of the coupling traveler above the bore are sufficiently close to the T-shaped flange to be guided thereby to prevent undesirable vertical or horizontal movement of the coupling traveler. Also, the coupling traveler is sufficiently relieved in the flange area to accommodate the screw-driven traveler therein. The coupling traveler is further provided with means for connecting it to a garage door, and carries a manually actuable bistable latch for selectively engaging and disengaging the coupling traveler with the screw-driven traveler for respective cooperative and independent slidable movement along the guide rail.

Traveler and guide rail apparatus for screw drive closure operator

An improved traveler apparatus includes a screw-driven traveler and a coupling traveler which are both slidably mounted within a track that is formed by the interior surfaces of opposed U-shaped channels of a guide rail. The guide rail also includes a screw channel which communicates through a longitudinal slot with the track. The screw-driven traveler includes a nut that engages a screw in the screw channel through the slot. The coupling traveler includes a manually actuable, bistable latch to selectively engage and disengage the coupling traveler and the screw-driven traveler for cooperative and independent slidable movement within the track, respectively, and the coupling traveler is adapted for connection to a closure, such as a garage door, to open or close same as the coupling traveler is moved along the track.

Traveler apparatus for screw drive closure operator

An improved position control apparatus is disclosed to control a motor-driven door operator to halt movement of a door at an open position and a closed position. The position control apparatus includes a control screw means in the form of a threaded shaft extension of the motor shaft or a threaded rod coupled to the motor shaft which is rotated when the motor is energized. A travel nut is threadedly engaged with the control screw means and is constrained against rotational motion so as to reciprocate along the control screw means. Position detection means, such as switches, are disposed near the control screw means for actuation by the travel nut to control the motor as the door approaches the open position and the closed position. In another embodiment, a toggle switch is mounted on the travel nut, and the switches are replaced by stops for actuation of the toggle switch to control the motor. An improved obstruction detector apparatus is also provided to control the motor if an obstruction is encountered as the door moves between the open position and the closed position. The obstruction detector apparatus includes a safety switch which is actuable by rotation of the motor casing due to reaction torque, if an obstruction is encountered as the door moves in one direction, and a lever that is actuable by rotation of the motor casing, if an obstruction is encountered as the door moves in an opposite direction, to actuate the safety switch.

Position control and obstruction detector apparatus for a motor-driven

A garage door operator includes a drive screw, rotationally and longitudinally movable in a shuttle track or guide rail, and a screw-driven shuttle mounted on the track and connected to the door. A lever arm is attached to the screw at a rearward end thereof and is pivoted to the operator at one side of the screw. Another end of the lever arm, adjacent an opposite side of the screw, is operatively disposed with respect to control switches and is spring-loaded, whereby door engaged obstructions cause the rotating screw to move longitudinally, against the spring bias, and to actuate, through the lever arm, a switch for stopping or for reversing the operator motor. A sleeve coupling permits longitudinal screw movement with respect to the operator's motor, and is provided with means to permit continued motor operation, drivingly disengaged from the screw, upon control malfunction, in order to prevent damage or injury.

Growing community of inventors

Broadview Heights, OH, United States of America

Maw H Lee