The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 13, 1988
Filed:
Apr. 06, 1987
Michael H McGee, Los Angeles, CA (US);
Other;
Abstract
A garage door opener with solenoid latches is provided with a circuit for energizing the coils of the solenoid latches with power from a 24-volt step-down transformer, either as 120 volt power is applied to a motor to move the door in response to detection of an initial surge of current or as a manual or radio controlled command switch is actuated. In either case, current at a higher level is applied initially to pull in the armature locking pins of the solenoid latches, and thereafter at a lower hold-in level. A transformer with a single turn primary winding or a Hall-effect device may be used to detect the initial surge of current to the motor and in response thereto pull in the locking pins. Thereafter, hold-in current is applied as long as current to the motor is sensed. In the case of sensing actuation of a command switch, a first one-shot triggered by the command switch times the total period (16 seconds) during which the solenoid latches are provided with at least hold-in current, and a second one-shot triggered by the first one-shot at the beginning of its timing period, times a short (100 ms) period during which high, pull-in current is applied. The second one-shot may also be used to inhibit application of power to the motor during the pull-in time. Still other embodiments utilize a mechanical means for sensing when power has been applied to the motor by the door opener.