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: An electronic door control system is disclosed having a d.c. motor rotatable in one direction for opening a door and in the opposite direction for closing the door. One or more semiconductor devices (preferably SCR's) supply d.c. power to the motor from an a.c. power source when rendered conductive. A polarity selecting circuit controls the polarity of d.c. power supplied to the motor and thus its rotational direction. A sensor (e.g. floor mat) senses body pressure near the door to enable conduction of the semiconductor device and provide a first d.c. power polarity for a predetermined period to open the door. A circuit reverses the polarity after the door is opened, thereby closing the door. A speed control circuit responsive to counterelectromotive force developed by the motor effectively controllably varies the conductivity of the semiconductor device in a sense tending normally to cause motor rotation, and thereby door movement, at a predetermined speed.

Abstract: A control circuit for an electrically driven vehicle has a switch with a central off position, and operative positions in which the motor of the vehicle drives the vehicle forwardly and rearwardly. Delay means is provided operable when the switch is in its central off position for maintaining energisation of the control circuit for a predetermined period of time, so that loads are not deenergised as the switch is moved through its off position to change the direction of operation of the truck. In the preferred form, movement of the switch to its off position reduces the demanded armature current to zero.

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.