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:
Feb. 10, 1981
Filed:
Nov. 14, 1978
Applicant:
Inventors:
Mitsuaki Takenoshita, Katsuta, JP;
Masayuki Shigeta, Katsuta, JP;
Assignee:
Hitachi, Ltd., , JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B66B / ;
U.S. Cl.
CPC ...
187 / ; 318 84 ;
Abstract
A speed control system for a hydraulic elevator, in which, actuating a hydraulic pump by driving an induction motor in forward direction, oil is supplied to a hydraulic cylinder for upward travel of an elevator cage, while the hydraulic pump is driven to discharge the oil from the hydraulic cylinder by driving the induction in reverse direction for downward travel of the cage. The induction motor is a single two-speed motor, which is switched to drive the hydraulic pump in one of the two speeds as desired, thus subjecting the elevator cage to two-speed control.