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:
Oct. 14, 1986
Filed:
Nov. 26, 1984
Toshiaki Ishii, Inazawa, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
Collision impacts between meshing gears in a speed reduction mechanism 11 of an elevator system due to backlash during transitions between power/driving and regenerative/driven modes of operation are reduced by detecting the actual or approaching separation of the gear teeth, and in response thereto temporarily reducing the motor torque to correspondingly reduce the equalized relative speed difference between the input and output shafts of the mechanism. Tooth separation may be detected by sensing a difference in amplitude between signals proportional to the input and output shaft speeds, equalized in accordance with the gear ratio, or by sensing a polarity change in the motor drive current. The motor torque may be reduced by the relay controlled switching of resistors 40, 43 in a speed controller to thereby convert the function of an operational amplifier 45 therein from a first order time lag circuit to an integrator.