Elevator system monitoring cold oil
US4785915A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 19, 1987 |
| Grant date | Nov 22, 1988 |
| Priority date | — |
| Expiry date | Jun 19, 2007 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB66B1/24
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A hydraulic elevator system for monitoring a cold oil thermostat mounted on a hydraulic oil reservoir to prewarm the oil prior to passenger service by recirculating the oil in the reservoir through a pumping path which goes past up and down valves, thus bypassing the hydraulic jack. A control circuit including a microprocessor generally controls all car and corridor functions and is photo-coupled to the thermostat for an input signal which interacts with a program module in a random access memory which is run in sequence by the microprocessor. The program module provides a minimum timer phase for pump motor energization which is short but normally adequate to circulate the oil to standard minimum operating temperature before the sequencing activates a maximum timer phase which is cumulative in time for continuous bypassing until shutdown. The tiered total timer counting thus prevents overtemperature problems to avoid damage to the pump motor windings if the thermostat fails and also prevents recycling.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.