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:
Dec. 15, 1992
Filed:
Nov. 19, 1990
Masamoto Mizuno, Inazawa, JP;
Terumi Hirabayashi, Inazawa, JP;
Masanori Tawada, Inazawa, JP;
Toshiyuki Kodera, Inazawa, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
An apparatus for controlling an elevator door comprises a motor which closes and opens the door of an elevator and applies to the door torque necessary for maintaining a closed state of the door, an inverter apparatus for controlling the driving of the motor, a polarity deciding device for deciding the polarity of a slip frequency signal output from the inverter apparatus, and a driving stop device for causing the inverter apparatus to stop the driving of the motor when the polarity deciding device detects the inversion of the polarity of the slip frequency signal during the time that a closed state of the door is maintained by the motor.