System for position loss recovery for an elevator car

• US 5,631,452 A
• Filed: 08/18/1994
• Issued: 05/20/1997
• Est. Priority Date: 08/18/1994
• Status: Expired due to Term

• Current Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Original Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Inventors: Izard, Jeffrey M., Jamieson, Eric K., Pietrzykowski, Christopher S.
• Primary Examiner(s): NAPPI, ROBERT E
• Application Number:
  US08/292,645
• Time in Patent Office: 1,006 Days
• Field of Search: 187/391, 187/394, 187/393
• US Class Current: 187/394
• CPC Class Codes: B66B 1/3492 Position or motion detectors or driving means for the detector B66B1/40, B66B1/50 take precedence; length measuring G01B; speed measuring G01P
• CPC Class Codes: G05B 19/4067 Restoring data or position after power failure or other interruption

Abstract

A system for position loss recovery for an elevator car includes a plurality of pairs of encoded floor magnets that uniquely identify each floor. Upon restoration of power, the encoded floor magnets are sensed by an encoded floor sensor and the precise floor location of the elevator car is determined.

Claims

1. A system for position loss recovery for an elevator car;

said system comprising;

signal generating means for generating signals indicative of the distance travelled by an elevator car within a hoistway;

floor location means, disposed within said hoistway, for indicating each floor location;

floor identifying means, disposed within said hoistway, for uniquely identifying each floor location, said floor identifying means including identification means having a length that is uniquely associated with a respective floor;

sensing means, affixed to said elevator car, for separately sensing said floor location means and said floor identifying means; and

processing means for processing signals from said signal generating means and signals from said sensing means to determine an exact floor location of said elevator car.

2. The system as claimed in claim 1 wherein said identification means includes a plurality of pairs of encoded floor magnets disposed within said hoistway, each said pair of said plurality of pairs of encoded floor magnets having a length that is uniquely associated with a landing number of said respective floor with which said pair is associated for uniquely identifying each said floor.

3. The system as claimed in claim 2 wherein said length of each said pair of encoded floor magnets is related to said floor by the formula:

L=(n)(UL);

wherein L is the length of each member of said pair of magnets;

n is an integer representing said landing number; and

UL is a predetermined unit length.

4. The system as claimed in claim 3 wherein said floor location means includes a plurality of door zone magnets, each said door zone magnet being associated with an elevator landing and precisely disposed along said hoistway with respect to said elevator landing.

5. The system as claimed in claim 4 wherein said system further comprises:

a vertically extending tape.

6. The system as claimed in claim 5 wherein said plurality of door zone magnets are disposed along a first edge of said tape.

7. The system as claimed in claim 6 wherein said plurality of pairs of encoded floor magnets are disposed along a second edge of said tape.

8. The system as claimed in claim 7 wherein the members of each said pair of encoded floor magnets are disposed on opposite sides of one of said door zone magnets.

9. The system as claimed in claim 8 wherein said sensing means includes means for guiding said sensing means along said tape such that said tape is maintained at a predetermined position with respect to said sensing means.

10. The system as claimed in claim 9 wherein said sensing means includes;

a leveling up sensor, a leveling down sensor, a door zone sensor, and an encoded floor sensor.

11. The system as claimed in claim 10 wherein said leveling up sensor, said leveling down sensor, said door zone sensor and said encoded floor sensor are Hall effect devices.

12. The system as claimed in claim 10 wherein said leveling up sensor, said leveling down sensor, and said door zone sensor are disposed proximate said first edge of said tape.

13. The system as claimed in claim 9 wherein said processing means includes an encoded floor counter for receiving pulses from said generating means and a microprocessor having a non-volatile memory associated therewith and accessible thereto.

14. The system as claimed in claim 13 wherein said encoded floor counter is gated by signals from said encoded floor sensor and said microprocessor receives the output from said encoded floor counter.

15. The system as claimed in claim 14 wherein said microprocessor receives inputs from said encoded floor sensor, said leveling up sensor, said leveling down sensor and said door zone sensor.

16. The system as claimed in claim 15 wherein said microprocessor includes a software program for calculating the floor number of said encoded floor magnets such that the position of said elevator car is known.

17. The system as claimed in claim 16 wherein said calculation is carried out in accordance with the formula:

n=(EFcounts)/(SF*UL);

wherein EFcounts is the number of gated counts from said encoded floor counter;

SF is a predetermined primary position counts/unit length scale factor and UL is the unit length of said encoded floor magnets.

18. A method for position loss recovery for an elevator car;

said method comprising the steps of;

generating distance signals indicative of the distance travelled by an elevator car within a hoistway;

generating floor location signals indicative of each floor location;

generating floor identifying signals that uniquely identify each floor location by sensing the length of floor identification means disposed within said hoistway, each said floor identification means having a length that is uniquely associated with a respective floor;

separately sensing said floor location signals and said floor identifying signals; and

processing said distance signals, floor location signals and said floor identifying signals to determine an exact floor location of said elevator car.

19. The method as claimed in claim 18 wherein said step of generating floor identifying signals includes the step of providing said floor identification means as a plurality of pairs of encoded floor magnets disposed within said hoistway, each said pair of said plurality of pairs of encoded floor magnets uniquely identifying each said floor.

20. The method as claimed in claim 19 wherein said step of processing includes the step of determining said length of said encoded floor magnets in accordance with the formula:

L=(n)(UL);

wherein L is the length of each member of said pair of magnets;

n is an integer representing said landing number; and

UL is a predetermined unit length.

21. The method as claimed in claim 20 wherein said step of processing includes the step of calculating a floor number in accordance with the formula:

n=(EFcounts)/(SF*UL);

wherein EF counts is a number of gated counts from an encoded floor counter and SF is a predetermined primary position counts/unit length scale factor.