Normal thermal stopping device with non-critical vane spacing
US6082498A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 22, 1999 |
| Grant date | Jul 4, 2000 |
| Priority date | — |
| Expiry date | Jan 22, 2019 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB66B1/40
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A normal terminal stopping device (NTSD) using terminal zone position checkpoint detection with a binary coding method to identify a checkpoint within a terminal zone, and a digital shaft encoder mounted on the shaft of the hoist motor to determine a car position relative to a target stopping point. A microprocessor-based controller is used to compare a velocity command signal to a velocity limit reference. If the velocity command exceeds the velocity limit, the NTSD functions will take over to cause the elevator car to decelerate at the NTSD rate. In particular, the velocity limit reference is computed according to lead compensation and curve shaping techniques to attain better drive tracking characteristics of the motion controller. Binary coded checkpoints are used to eliminate error introduced in a car position derived from a motor shaft digital encoder. The normal terminal stopping device and method according to the present invention is less sensitive to the vane spacing as compared to the conventional NTSD designs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.