HYDRAULIC ELEVATOR DRIVE SYSTEM

摘要

HYDRAULIC ELEVATOR DRIVE SYSTEM A hydraulic elevator drive system utilizes an elevator car speed signal and a commanded velocity signal to provide an electrical error signal and controls the operation of a fluid control regulating the fluid flow between a hydraulic actuator which moves the car, a hydraulic pump and a fluid reservoir. The fluid control includes a combined check and lowering valve and a by-pass valve selectively operated by a common control element including a dynamically operated control piston responding to the error signal. Another check valve couples the fluid pump to the fluid control while a pair of manually preset control valves regulate the supply of fluid to the control piston for providing pre-established acceleration limitations to the elevator car.