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:
May. 05, 1987
Filed:
Jun. 11, 1985
Hideo Uchino, Aichi, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
In an apparatus for automatic floor arrival at the time of service interruption in an A. C. elevator which is operated by an A. C. variable-voltage and variable-frequency control; when a slip frequency value during acceleration is at least a predetermined value, a burden raising mode is decided to switch running directions. Thus, in case of performing a rescue operation at the time of the service interruption, a load torque can be simply and reliably detected from the slip frequency value, and the elevator can be operated in a burden lowering direction. Another construction is such that slip frequency values during acceleration are integrated, and when the slip frequency integration value is at least a predetermined value, a burden raising mode is decided to switch the running directions. In the rescue operation at the time of the service interruption, whereby the possibility of an erroneous control ascribable to the influence of a ripple component included in the slip frequency during the acceleration can be reduced to the greatest extent.