Abstract: The present invention relates to an electronic circuit that interrupts the application of electrical power to a motor after a predetermined period of time. The electronic circuit is disposed between a motor which drives a device from an initial position to a final position and a switch movable from a first position to a second position. A battery which supplies the electrical power for the motor is engaged with the switch. The control circuit includes at least two energy storage devices. Depending on the position of the switch, one of the energy storage devices will be fully charged by the battery source. Altering the position of the switch will cause the fully charged energy storage device to begin its discharge and the alternate energy storage device will be “instantly” charged. During the time that both energy storage devices have a significant charge on them, a control signal is generated.

Abstract: Soiled and/or contaminated objects often have to be collected before they are specifically disposed of. According to the invention, in order to prevent blockages in toilets and sewers, a contactlessly operating container (1) is used which has a lid (2) which opens when a hand or an object approaches a proximity detector (50). The container (1) is suspendable from a supporting housing (12) accommodating the entire control means, the drive and the power supply. A preferred use of the device is the disposal of sanitary towels (14) which are immersed in a gel (15). The container (1) is periodically replaced by a clean container so that satisfactory hygiene conditions can also be maintained in frequently used toilet areas.

Abstract: An automatic gate operator includes an electric drive motor coupled by a drive train to a movable gate, and includes provisions for sensing an actual or impending obstruction or blockage of the movement of the gate by a human, object, or animal, for example. In response to such an actual or impending blocking of the gate's movement, the drive motor is shut off and the gate is braked to a stop. Then the gate is reversed to move a short distance away from the actual or impending blockage or obstruction, and is braked again to a stop. Next, the gate is freed from its connection with the drive motor, allowing manual movement of the gate to allow clearance of the actual or impending blockage or obstruction from the path of the gate. This stop-reverse-stop-release sequence of movements for the gate may release any entrapped person or object which may have been contacted by the moving gate. Also, after the gate is released for free movement it can be moved manually.

Abstract: A screen wiping apparatus, in particular for an opening window of a motor vehicle, comprises an electric motor which drives at least one screen wiper in oscillating motion between two reversal positions, namely a fixed inner stop position and a fixed outer stop position. In addition, the blade is able to be retracted into a parked position which lies away from the window, when the window is to be opened. The apparatus includes a control system whereby the power supply voltage to the motor is variable by adjustment between a zero voltage and a maximum or full power voltage. The control system includes means for reducing the power supply voltage to the motor when the screen wiper passes from the fixed inner stop position to the off-window parked position.

Abstract: A windscreen wiper device includes at least one wiper arm (10) that is driven by an electric motor (11), whose rotary direction is variable at least in the respective extreme position. Upon the change of rotary direction, the electrical power made available to the electric motor (11) is reduced. The rated power is not made available until either a specified time has elapsed or a specified position of the wiper arm (10) has been reached. For specifying a reduced electrical power, a reduction in the current flowing through the electric motor (11) is especially well-suited. The windscreen wiper device according to the invention makes for a slight thermal load on both the electric motor (11) and the drive stage (19).

Abstract: A control method is disclosed that is applicable to a washing machine having an apparatus for automatically opening/closing a washer door using a motor. The control method comprises the steps of operating the motor in a direction to transition the door between open and closed states. When a command to transition the door is entered, door motor operation is stopped if the door is successfully transitioned between states within a predetermined time interval (t1) that is started at the time of the beginning of the operation of the door motor. The door is returned to an original position (e.g., closed) if the door does not transition to a position opposite (e.g., open) the original position by the time interval (t1) elapses.

Abstract: A laundry washing machine in which the period of each agitation stroke (comprising "ramp", "plateau" and "coast" phases) is controlled by adjusting the "coast" phase of each stroke in order to maintain consistent washing performance. The "coast" phase is initiated (after a predetermined period has elapsed in the "plateau" phase) by starting a timer and allow the motor to coast until the motor velocity drops to a predetermined reversal velocity at which point the motor is reversed to begin the next agitation stroke. The value of the timer when the velocity reaches the reversal velocity is compared to a desired value or range of values. The predetermined value of the reversal velocity is increased if the timer value is greater than the desired value or range of values. Alternately, the value of the reversal velocity is decreased if the timer value is less than the desired value or range of values. The period of the coast phase of the next agitation stroke should then be closer to the desired period.

Abstract: An opening/closing control apparatus detects an overload placed on a movable member of a vehicle such as a sunroof and a power window while it is sliding. Further, it prevents overload detecting operation (reversing motion) from being made by a cause other than an overload. A control processor circuit compares a driving current value of a motor detected at predetermined intervals with a preset current value and corrects an overload threshold value to a threshold value of higher value when the driving current value detected when a first predetermined time period has passed after the start of the motor does not exceed the preset current value. Thereafter, the control processor circuit determines that an overload has occurred when a change in the driving current value has exceeded the overload threshold value.

Abstract: This invention relates to a skew motor driving circuit of satellite video receiver for eliminating a remaining voltage of ripple form generated at skew motor in a satellite video receiver such as SVR and the like. The invention is an apparatus for receiving a satellite video, a third transistor Q3 for executing on/off operation in response to control signal controlling a skew motor, a first transistor Q1 for supplying/cutting a skew motor input power 1 in conjunction with the operation of the third transistor, a fourth transistor Q4 for eliminating a remaining voltage remaining upon cutting a driving voltage supplied to said skew motor by an operation being contrary to the operation of said first and third transistors, and a second transistor Q2 for supplying skew pulses to the skew motor in response to the skew pulse signal.

Abstract: A tape cutting mechanism uses a bi-directional motor and a clutch arrangement. However, with the use of such a clutch in an inexpensive open loop control system, the dynamic energy stored in the motor armature at the initiation of the cutting sequence is greater than the maximum energy required and the maximum cutting energy requirements vary considerably. Leftover energy is removed from the system in order to prevent a large impact at the end of its stroke which may damage the clutch mechanism and to decrease the noise by controlling the bi-directional motor for oscillating a member for cutting a tape and for feeding the cut tape.

Abstract: In order to improve a method for monitoring movable elements, in particular windows and sunroofs in motor vehicles, such that an object clamped between the movable parts and the part at rest is detected in a reliable fashion, the force acting upon such objects is maintained at the lowest possible value and the direction of the window is inverted as rapidly as possible. In order to ensure a reliable protection, a cutoff threshold consists of a constant component and a variable component, with the size of the difference (Dn) between the cutoff threshold and the instantaneous value of the rotation time (tu) influencing the switching signal.

Abstract: In an apparatus for driving and controlling a power window according to the present invention, a blanking period is provided to stop the comparison between a variation amount of motor current and a threshold value, during a predetermined period of time T after the drive of the motor has been started. The catching of a foreign object is detected based on the motor current value in the latter half Tm of the blanking period, and is detected based on the variation amount of the motor current after the blanking period. Erroneous operation due to noise at the beginning of the drive of the motor is prevented, and the catching of a foreign object is reliably detected.

Abstract: A drive motor for a motor vehicle screen wiping apparatus operates with repeated reversals of its direction of rotation, and is controlled by a control circuit which is connected to a transistor arranged in the power supply path for the motor, in series with it. The transistor is put into conduction at a time, and in a manner, such as to reduce the audible noise caused by the repeated reversals.

Abstract: A motor control device which prevents runaway reverse rotation arising from failure of detection of a rotational speed drop of a motor to a preset value when reverse torque braking is applied. In the first invention, rotation drop detection section 5 detects, from rotational pulses P1 generated by rotational pulse generation section 4, a rotational speed drop to the preset value and outputs rotation drop detection pulse P2. Timer section 6 is activated by rotation stopping signal S1 and outputs pulse P3 upon lapse of the maximum rotation stopping required time of the motor. Control section 1 delivers, upon reception of rotation stopping signal S1 from the outside, a signal to apply reverse torque to motor drive section 2 and then delivers, upon reception of rotation drop detection pulse P2 or pulse P3, an instruction to stop reverse torque. In the second invention, timer section 7 is additionally provided.

Abstract: An improved window operator has an electrically controlled drive for moving a window between opened and closed positions in response to a command. A plurality of switches are provided for manually or remotely commanding movement of the drive to move the window to a select desired position between the opened and closed positions. A position sensing routine senses actual position of the window between the open and closed positions. The position sensing routine includes a timer for storing a value representing actual position. The value is selectively incremented or decremented at a select rate in response to duration of operation of the drive to move the window between the open and closed positions. The control senses electrical power supplied to the drive. An adjustment routine adjusts the select rate of the timer in response to electric power deviating from a select desired power level.

Abstract: A safety device for a power window which, if one's hand or neck is caught between the window glass and the sash, detects such state instantaneously and accurately to perform a safety control operation. Respective detectors detect the absolute and relative speeds of a power window opening or closing operation to determine whether or not a foreign object is caught in the window. When at least one of the detectors detects a foreign object being caught in the window, a safety control operation is carried out, for instance, stopping the movement of the window glass. Since the absolute speed and the relative speed are utilized in combination, a dangerous state can be detected instantaneously and accurately. Also, backlash in the drive mechanism for the window can be detected, and the safety control operation inhibited during such times to prevent erroneously effecting a safety control operation.

Abstract: The improvement of a remotely controlled ceiling fan is achieved mainly by means of a function control IC communicating with TRIAC Q.sub.8, TRIAC Q.sub.9 and TRIAC Q.sub.10 of the speed-changing device via lines Q.sub.5, Q.sub.6 and Q.sub.7 connecting respectively with points 11, 12 and 13 of the function control IC, so as to transmit a command from the function control to the speed-changing device which in turn controls the speed of motor. The function control IC is additionally provided at point 16 thereof with a delay device, which in turn is connected to a relay via line Q.sub.11. The primary line coil of the motor communicates with the relay intended to initiate a change in the polarity of the primary line coil of motor at the time when the function control IC receives a command to put the operation of motor in reverse and the speed-changing device is halted temporarily.

Abstract: Apparatus for inhibiting high torque created by the application of reverse voltage to a conventional motor with a field coil and armature operating in the opposite direction comprising a pair of drive resistors in series with the motor, a corresponding normally open contact connected in parallel to each respective drive resistor, an energizing coil corresponding to each contact, a timing circuit and an inhibitor circuit. During high speed forward operation, both coils are energized, closing both contacts, shorting out both drive resistors and maximizing motor voltage. When reverse operation is desired, a reverse voltage is applied across the armature, resetting the timing circuit and activating the inhibitor circuit. The inhibitor circuit will deenergize the coils, opening the contacts and remove the short across the drive resistors and thus reduce the reverse voltage being applied and permit gradual deacceleration.

Abstract: A control circuit for connecting a load to a voltage source includes an electronic holding circuit having latched and unlatched states. When latched, the electronic holding circuit connects the load to the voltage source. A thermal device responsive to excessive current demand by the load automatically places the holding circuit in its unlatched state, and disconnects the load from the voltage source. The circuit may also be placed in its unlatched state by sensing a current in a resistor to unlatch the circuit without requiring a current sufficient to cause the thermal device to respond.

Abstract: A garbage container is disclosed, which will open automatically when a user is present in front of the container and will close after a predetermined time of the departure of the user. This garbage container comprises an infrared ray transmitter and an infrared ray receiver to detect the presence of a user.

Abstract: In a motorized automobile antenna control device for an antenna system wherein an antenna is raised when power supply of a radio receiver is switched on and lowered when the power supply is switched off, the antenna is prevented from being lowered for a predetermined period of time, for example two to ten seconds, after the power supply of the radio receiver is turned off by a timer so that unnecessary raising and lowering motions of the antenna are prevented when an ignition switch of an automobile is turned on.

Abstract: Motor control apparatus comprised of a drive circuit for supplying drive current to a motor, an overload detector coupled to the motor for detecting the magnitude of the motor current to produce an output signal if that current exceeds a predetermined threshold level caused by motor overload, and a control circuit coupled to the drive circuit and responsive to the output signal for controlling the drive current supplied to the motor, thereby controlling motor operation.

Abstract: A passive seat belt system comprises a seat belt adapted to reciprocate between a fasten end and a release end so as to be fastened and released to and from a rider, a motor for driving the seat belt, and a controller for controlling the motor so as to fasten and release the seat belt to and from the rider as he enters and exits the vehicle. The controller controls the motor in such a manner that the motor is stopped and then reversely rotated after the lapse of a predetermined period when the motor is to be reversely rotated during rotation thereof.

Abstract: Garage door controllers are improved by means to automatically close the doors after a preselected delay time, once they have been opened.

Abstract: Apparatus for inhibiting high torque created by the application of reverse voltage to a conventional motor with a field coil and armature operating in the opposite direction comprising a pair of drive resistors in series with the motor, a corresponding normally open contact connected in parallel to each respective drive resistor, an energizing coil corresponding to each contact, a timing circuit and an inhibitor circuit. During high speed forward operation, both coils are energized, closing both contacts, shorting out both drive resistors and maximizing motor voltage. When reverse operation is desired, a reverse voltage is applied across the armature, resetting the timing circuit and activating the inhibitor circuit. The inhibitor circuit will deenergize the coils, opening the contacts and remove the short across the drive resistors and thus reduce the reverse voltage being applied and permit gradual deacceleration.

Abstract: A field installable motor operator for a circuit breaker includes a bidirectionally controllable motor that is coupled through a torque limited module to a circuit breaker operating mechanism. The motor is bidirectionally driven by a transistor switching bridge that supplies output current in reversible flow directions through one of the windings of the motor to the input of a rectifier bridge that supplies the other winding with currents that flow in the same direction. The torque limited module includes a centering and spacing ring which precisely confines the clutch elements to provide consistent torque. The motor is supplied with a current pulse of 250 milliseconds duration that is longer than the time required to fully operate the breaker. The clutch slips when breaker operation is completed and permits the motor to overrun without damage.

Abstract: A field installable motor operator for a circuit breaker includes a bidirectionally controllable motor that is coupled through a torque limited module to a circuit breaker operating mechanism. The motor is bidirectionally driven by a transistor switching bridge that supplies output current in reversible flow directions through one of the windings of the motor to the input of a rectifier bridge that supplies the other winding with currents that flow in the same direction. The torque limited module includes a centering and spacing ring which precisely confines the clutch elements to provide consistent torque. The motor is supplied with a current pulse of 250 milliseconds duration that is longer than the time required to fully operate the breaker. The clutch slips when breaker operation is completed and permits the motor to overrun without damage.

Abstract: A reversible electric motor is operatively arranged to drive an air circulating fan. Circuitry is provided to reverse the direction of rotation of electric motor periodically to provide alternating direction of air movement. Timing and reversal is provided by either a timing clock, a microprocessor, a thermal relay or a rotating disc which carries a pair of touch stops therein.

Abstract: A safety circuit for a window lift driven by an electric motor is described which causes a reversal in the direction of rotation of the drive motor when the window pane impinges on an impedance in its upward motion. The reversal criterion used is the motor current surge familiar to the state of the art. The circuit of the invention is characterized in that upon actuation of the "close" window key, the drive motor first rotates briefly in the direction of opening and thereby displaces the window pane downwardly, whereupon it is automatically reversed and only then does the pane motion toward the closed position begin. Consequently, the motor start-up peak current decays in that range of displacement of the window pane which is below its initial position, whereby an increase in current (di/dt) after resuming the initial position of the window pane at once causes motor reversal.

Abstract: A control device for a reversible D.C. electric motor to protect it against damage upon reversal has a input switch circuit for reversing the flow of current through the motor's armature for reversing the direction of rotation of the motor, a first control circuit for preventing flow of current via the input switch circuit to the armature initially upon current reversing and a second control circuit for periodically interrupting the flow of current while the motor gains rotational speed after being reversed in relation to the magnitude of the flow of current through the armature. The first control circuit includes a detector circuit for determining the voltage drop existing across the armature and an automatic switch unit for (1) blocking flow of current from the input switch means to the armature until the voltage drop is determined by the detector circuit to be in a predetermined range and (2) allowing flow of the current while the voltage drop is determined to be within the range.

Abstract: A window wiper control system provides accurate regulation and/or profiling of wiper speed. A desired interval corresponding with the preselected speed or speed profile is stored; a reference signal is provided to indicate a reference position of the wiper and is used to measure the actual interval of a wiper stroke or cycle. The actual interval is compared with the desired interval and an appropriate adjustment is made in a pulse-width modulation signal for effecting a desired speed and interval. The pulse-width modulation signal preferably has a relatively-low repetition rate. The wiper speed may be profiled to include acceleration and deceleration, and the intervals of acceleration and deceleration may be lengthened substantially to provide an apparent dwell.

Abstract: An electric drill safety device is provided for dynamically braking a drill when there is contact between the drill bit and an electrically conductive material. A first direction voltage is applied to the motor winding to turn the motor forward. When contact is detected between the drill bit and an electrically conductive material, voltage to the windings is discontinued momentarily and thereafter a reverse direction voltage is provided to the motor windings for a predetermined time.

Abstract: This invention is a variable automatic forward/reverse control device for an unattended baby cart which is particularly designed for the housewife who is too busy at home to take care of her baby in the cart. Placing the baby in this cart equipped with this control device and taking advantage of the device may make this cart automatically advance a preset distance and then automatically back a preset distance, without worrying about this cart ramming against a room wall or some stationary objects indoors. Thus, the baby will feel quite safe and not cry. In addition, this cart may be provided with music to let the housewife use her spare time to do some handicraft or other chores. Furthermore, the timing equipment or rang-finding computer in the control device may be adjusted to close to zero time so that this cart can slightly vibrate to-and-from in situ so that in such circumstances, the baby will not cry.

Abstract: A control for a vehicle window driving motor in an H-switch semiconductor bridge with an SCR and a FET in each opposite armature current path includes control logic circuitry enabling one-touch actuation of window movement in either direction with stoppage by actuating either actuation device and with flip-flop control of the bridge elements to prevent shorting out the power supply. A variation provides automatic stoppage in the up direction by stall current sensing with automatic reverse after a time delay to allow the SCR conducting during upward movement to turn off.

Abstract: A security timer for a powered overhead garage door causes the garage door to close after it has been opened for a selected time interval. The security timer includes an oscillator that provides pulses. A counter counts the pulses and provides a binary output. A timer switch is engaged by the door when the door is fully open. Engagement of the timer switch signals the oscillator and counter to begin. When the desired number of pulses has been counted, a relay switch is closed for signaling the operator unit of the door to close the door.

Abstract: An electric starting system for cranking an internal combustion engine by an electric cranking motor. The system prevents energization of the cranking motor following initial energization and subsequent deenergization by sensing the voltage generated by the cranking motor when it is deenergized and preventing reenergization of the cranking motor until this voltage drops to some value indicative of a low cranking motor speed.

Abstract: A circuit for controlling an electrically operated garage door comprising a manually operated switch disposed within the garage. By actuating the manually operated switch twice within a prescribed period of time, the garage door is either opened or closed depending on its state. For automatically closing the garage door, a tape switch is disposed on the garage floor in the vicinity of a garage door. The tape switch extends across the garage floor in a direction to be actuated by the front and rear wheels of the vehicle. When a vehicle leaves the garage or has entered the garage, the successive actuations of the tape switch by two sets of wheels complete an operating circuit to close the garage door. The garage door is also opened by the manual operation of a digit selecting switch and a digit sequencing switch which are located outside of the garage. A preselected code is stored in a code circuit by a set of presettable mechanical switches representing the respective digits of the code.

Abstract: A control system for the stroke limitation of a machine tool element in which the element is connected with the slider of a potentiometer so that the voltage on the potentiometer slider varies in a respective direction with each direction of movement of the tool element. A pair of adjustable resistors are provided which form voltage sources with voltages conforming substantially to that of the potentiometer slider at the desired points of reversal of the tool element. The slider voltage is compared with the voltage at the adjustable resistors and the tool element is reversed when the slider voltage bears a predetermined relation to the voltage with which it is compared. A selectively adjustable delay could also be provided to delay the reversing of the tool element at at least one of the limits of travel thereof.

Abstract: Control device responding to current changes in a load circuit including a supervisory circuit carrying a current proportional to the current in the load circuit, a transformer coupling the supervisory circuit to the load circuit, and an overcurrent sensor and an overcurrent relay electrically connected in series in the supervisory circuit. The overcurrent sensor being set to deliver a signal when a given first current value is reached after a response delay, the overcurrent relay being able to interrupt the load circuit if a given second current value is reached after an adjustable response delay, and a method of operating the control device in a waste crushing machine.

Abstract: A D.C. motor directional control in which relays switch the polarity of the D.C. voltage applied to the motor armature in order to obtain forward or reverse operation of the D.C. motor. A SCR is connected in the armature circuit to control the current of the armature circuit. A control circuit which includes a triggering circuit for the SCR is responsible for the sequential operation of the armature relay contacts and the firing of the SCR. Contacts on forward and reverse relays actuate a common relay, which in turn actuates the SCR triggering circuit. Either the forward or reverse relay must be actuated before the common relay will be actuated, therefore, the forward or reverse relay contacts in the armature circuit close before the common relay actuates the SCR triggering circuit. A delay circuit includes a capacitor connected in parallel with the forward and reverse relays.

Abstract: A control system for an induction electric motor utilized to drive a top loading agitator washing machine obviates the need for a mechanical transmission between the motor and the agitator of the washing machine. An integrated circuit module in the control system provides a nearly infinitely adjustable rate of output reversal. A plurality of phase shift capacitors enable a variety of output torques to be obtained from the motor.

Abstract: A variable speed motor control system for controlling the vertical speed of a hoist. An electro-mechanical brake means locks the hoist load in place when the system is off or when the motor speed is set at a zero speed setting. A quick response circuit is connected into the system for a predetermined time duration after the system is switched from a zero speed to any speed setting (high or low speed), to enable the motor to quickly gain control over the load and prevent the load from slipping as the motor accelerates to the set speed after the brake is released. An initial delay timer is turned on when electrical power is first connected into the system, to prevent transfer of electrical power to the motor and to prevent release of the brake, for a predetermined period of time. A hoist (up-down) electro-mechanical contactor connects electrical power from a source to a thyristor static switch.

Abstract: A control means for the wire wrapping machine comprising a lead wire wrapping spindle and an outer fixed sleeve for rotatably supporting the spindle in which after completion of the wire wrapping operation an inverse current is supplied to a motor for the short period to allow the spindle to rotate reversely so that a slot provided in the spindle always comes to a position in alignment with a recess provided in the outer sleeve.

Abstract: Lift trucks (10) have many hand control levers which are manipulated to hoist a load, propel the lift truck (10) forward and rearward, and steer the lift truck (10). Some operations must be performed sequentially rather than simultaneously which increases loading time. An electronic directional control circuit (34) includes apparatus (36) for producing first and second command signals, apparatus (38) for producing first and second outputs in response to the first and second command signals, and apparatus (40) for delaying production of a preselected one of the first and second outputs a preselected time sufficient for the selected output to decrease to a preselected magnitude prior to the production of the other of the first and second outputs. The electronic directional control circuit (34) is useable with vehicles (10) which initiate the command signals with a foot operated pedal (12) while leaving the hands free for simultaneously operating other controls.

Abstract: A machine for applying twine to a package, tying and severing the twine embodies a continuously operating electric drive motor and a mechanical clutch which is intermittently engaged by a machine operator utilizing a foot treadle. The mechanical clutch disengages following an operational cycle of the tying machine. Should the clutch be engaged when the machine is idle and should the motor subsequently be turned on, the tying mechanism is instantly activated creating a dangerous condition for the machine operator. The invention renders the machine safe under all conditions through the provision of a simplified electrical motor control device which assures a short duration reversal of the electric drive motor and associated mechanism sufficient to release the mechanical clutch and eliminate the safety hazard before the motor begins its normal continuous forward drive.

Abstract: A pocket door is moved between open and closed positions by an electric motor unit mounted on the studs framing the rough opening in which the door is installed. The rotary motion of the motor is translated into linear motion by a cable and pulley arrangement with one of the pulleys being a drive pulley on the shaft of the motor unit and the other being an idler pulley mounted on the track on which the door slides. The cable is attached to the door through a coil-type tension spring. Hence, the door will move when the motor is energized and should the door encounter an impediment upon closing the spring will expand and permit the pulley to slip within the loop of the cable. The motor is controlled by a timer which when activated causes the motor to run for sufficient time to open the door, then hold to enable one to pass through the door opening, and then run in the opposite direction for sufficient time to close the door.

Abstract: An add-on device for automatically adjusting the setting of a control mechanism, such as, a thermostat, which includes a separate, independent timer which is mounted adjacent the existing control mechanism and controls the same by means of a mechanically driven member which engages the manual adjuster of the control mechanism; the device further including a suitable coupler for coupling the driven member to the timer for moving the driven member at selected times to change the position of the adjuster.

Abstract: The disclosure relates to a safety device for use in a garage door opening and closing system of the type which includes an impulse actuated reversible motor which opens and closes the garage door and wherein the safety device automatically actuates the motor for closing the door should the door be inadvertantly opened or accidentally remained open. The safety device includes a detector for detecting the open or closed condition of the door, a counter for keeping time responsive to the detector detecting that the door is open, and a logic circuit for providing repetitive impulses to the motor to actuate the motor for closing the door. The counter terminates keeping time and is reset by the detector when the detector detects that the door is closed. The safety device additionally includes an indicator responsive to the repetitive impulses for indicating that the logic circuits have actuated the motor for closing the door.

Abstract: A control device for an electric fan comprising a power supply, a control means, a trigger pulse generator and a switch means, all connected in circuit with the motor of the electric fan, wherein the trigger pulse output of said trigger pulse generator is connected to trigger said switch means and is controlled through said control means to thereby achieve a stepless, variable speed control for the electric fan. Other forms of the device may further comprise a delay means, and/or delay reverse means, and/or wave generator means and/or any combination thereof, connected in the above circuit to accomplish stepless speed reduction and/or delay speed-down reverse and/or various kinds of imitative natural wind rotational speeds for the electric fan.